proceedings of the 4 renewable energy sources - research ......economy (gs-rb-s-re-de), warsaw,...

4th Renewable Energy Sources - Research and Business RESRB 2019 conference

Proceedings of the 4th Renewable Energy Sources - Research and Business RESRB 2019 conference July 8-9, 2019, Wrocław, Poland

http://resrb.budzianowski.eu

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Proceedings of the 4th Renewable Energy Sources - Research and Business conference

July 8 - 9, 2019, Wrocław, Poland




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EXECUTIVE ORGANISERS

InnovateWise

Wojciech Budzianowski Consulting Services

PATRONS

Global Society for Research and Business in Sustainability, Renewable Energy and Digital Economy (GS-RB-S-RE-DE), Warsaw, Poland




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International Scientific Committee (ISC) Wojciech Budzianowski - Chair (Wojciech Budzianowski Consulting Services, Wrocław, Poland) Wei-Hsin Chen (National Cheng Kung University, Tainan, Taiwan) Patrick Hendrick (Université Libre de Bruxelles, Brussels, Belgium)

József Popp (University of Debrecen, Debrecen, Hungary) Rainer Hinrichs-Rahlwes (European Renewable Energies Federation, Brussels, Belgium)

Abdellatif Zerga (Pan African University, Tlemcen, Algeria)

Scientific Advisory Board (SAB) Nicolas Abatzoglou (Université de Sherbrooke,

Sherbrooke, Canada) Hafez Abdo (Nottingham Business School, Nottingham, UK) Saleh Abujarad (Universiti Teknologi Malaysia, Johor

Baharu, Malaysia) Mustafa Acaroğlu (Selçuk University, Konya, Turkey) Frank Adam (University of Rostock, Rostock, Germany) Masoud Aghajani (Petroleum University of Technology,

Ahwaz, Iran) Ali Al-Waeli (The National University of Malaysia, Seri

Kembangan, Malaysia) Sofiane Amara (Université Abou Bekr Belkaid, Tlemcen,

Algeria) Oluwamayowa O. Amusat (University College London,

London, UK) Venkata R. Ancha (Jimma University, Jimma, Ethiopia) Sudá de Andrade (Federal University of Rio de Janeiro,

Rio de Janeiro, Brazil) Ahmed Aly (Aarhus University, Roskilde, Denmark) Rafael de Arce (Universidad Autónoma de Madrid,

Madrid, Spain) Akram Avami (Sharif University of Technology, Tehran,

Iran) Adrián Mota Babiloni (Jaume I University, Castelló de la

Plana, Spain) Yadira Bajon Fernandez (Cranfield University, Bedford,

UK) Nagaraj Banapurmath (KLE Technological University,

Vidyanagar, India) Alireaz Banisharif (Petroleum University of Technology,

Ahwaz, Iran) Róbert Barthos (Institute of Materials and Environmental

Chemistry, Hungarian Academy of Sciences, Budapest, Hungary) Andrea Bassi (KnowlEdge Srl, Rome, Italy) Smruti Ranjan Behera (Indian Institute of Technology

Ropar, Rupnagar, India) Belkacem Belabes (Centre de Développement des

Energies Renouvelables (CDER), Algiers, Algeria) Mohamed Sélmene Ben Yahia (Tunis-El Manar

University, Tunis, Tunisia) Naima Benbouza (University Kasdi Merbah, Ouargla,

Algeria) Mohamed Benchagra (University Hassan 1, Khouribga,

Morocco)

Abdelmajid Berdai (Ecole Nationale Supérieure

d’Electricité et de Mécanique, Casablanca, Morocco) Asfaw Beyene (San Diego State University, San Diego, USA) Shailendra Singh Bhadauria (National Institute of

Technology, Jalandhar, India) Abdul Rauf Bhatti (Government College University

Faisalabad, Faisalabad, Pakistan) Andrzej Białowiec (Wrocław University of Environmental

and Life Sciences, Wrocław, Poland) Melike Bildirici (Yildiz Technical University, Istanbul,

Turkey) Faik Bilgili (Erciyes University, Kayseri, Turkey) Hasan Huseyin Bilgic (Iskenderun Technical University,

Iskenderun, Turkey) Nicu Bizon (University of Pitesti, Pitesti, Romania) Juris Blūms (Riga Technical University, Riga, Latvia) Antonio Bogado (Federal University of Rio de Janeiro, Rio

de Janeiro, Brazil) Alex Van den Bossche (Ghent University, Ghent,

Belgium) Mohammed Bou-Rabee (College of Technological

Studies Kuwait, Surra, Kuwait) Amine Boudghene Stambouli (University of Sciences

and Technology of Oran, Oran, Algeria) Kestutis Buinevicius (Kaunas University of Technology,

Kaunas, Lithuania) Melda O. Çarpınlıoğlu (University of Gaziantep,

Gaziantep, Turkey) Foued Chabane (University of Biskra, Biskra, Algeria) Ricardo Chacartegui (University of Seville, Seville, Spain) Luís Dias Carlos (University of Aveiro, Aveiro, Portugal) Bin Chen (Beijing Normal University, Beijing, China) Gianfranco Chicco (Politechnico di Torino, Torino, Italy) David Chinarro Vadillo (Universidad San Jorge,

Zaragoza, Spain) Lackson Chisanu (University of Malawi, Zomba, Malawi) Isaac Chitedze (Mzuzu University, Mzuzu, Malawi) Tai-Shung Neal Chung (National University of

Singapore, Singapore City, Singapore) Frans Coenen (University of Twente, Enschede, The

Netherlands) Caglar Conker (Iskenderun Technical University,

Iskenderun, Turkey)




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Sandra Correia (University of Aveiro, Aveiro, Portugal) Youssef Dabaki (University of Tunis, Tunis, Tunisia) Devi Prasad Dash (Indian Institute of Technology Ropar,

Rupnagar, India) Yulin Deng (Georgia Institute of Technology, Atlanta, USA) Zaynah Dhunny (University of Maritius, Mauritius,

Mauritius) Nadjib Drouiche (Centre de Recherche en Technologie

des Semi-conducteurs pour l’Energétique (CRTSE), Algiers, Algeria) Magdalena Dudek (AGH, Kraków, Poland) Arkadiusz Dyjakon (Wrocław University of Environmental

and Life Sciences, Wrocław, Poland) El Mehdi El Khattabi (University Sidi Mohamed ben

Abdellah, Fez, Morocco) José María Encinar (Extremadura University, Badajoz,

Spain) Maohong Fan (University of Wyoming, Laramie, USA) Mustapha Faraji (Hassan II University, Casablanca,

Morocco) Yee-Chang Feng (BSME of National Cheng Kung

University, Tainan, Taiwan) Mario Luigi Ferrari (University of Genoa, Genoa, Italy) Marco Ferrarotti (Université Libre de Bruxelles, Brussels,

Belgium) Alberto Fichera (University of Catania, Catania, Italy) Mirko Filipponi (University of Perugia, Perugia, Italy) Risto Filkoski (University Ss Cyril and Methodius, Skopje,

Macedonia) Maria B. Forleo (University of Molise, Campobasso, Italy) Jagruti Gandhi (Texas A&M University, College Station,

USA) Fausto Pedro Garcia Marquez (University Castilla La

Mancha, Ciudad Real, Spain) Marla T.B. Geller (Federal University of Western Pará,

Santarém, Brazil) M. Serdar Genç (Erciyes University, Talas, Turkey) Simone Giorgetti (Université Libre de Bruxelles, Brussels,

Belgium) Celina Gonzalez (Universidad Politécnica de Madrid,

Madrid, Spain) Juan Félix González (Extremadura University, Badajoz,

Spain) Belkacem Gouasmi (University of Blida, Blida, Algeria) Inmaculada Guaita-Pradas (Polytechnic University of

València, València, Spain) Arvi Hamburg (Tallinn University of Technology, Tallinn,

Estonia) Hafida Hanine (University of Sultan Moulay Slimane, Beni

Mellal, Morocco) Arif Hepbasli (Yaşar University, Izmir, Turkey) Nadia Hidar (Cadi Ayyad University, Marrakesh, Morocco) Hikmat S. Hilal (An-Najah National University, Nablus,

Palestine) Ioan Cristian Hoarcă (National R&D Institute for

Cryogenics and Isotopic Technologies (ICIT), Rm. Valcea, Romania)

Michel Huart (Université Libre de Bruxelles, Brussels,

Belgium) K.S. Hui (University of East Anglia, Norwich, UK) Masayuki Ichinose (Tokyo Metropolitan University,

Tokyo, Japan) Ali Idlimam (Cadi Ayyad University, Marrakesh, Morocco) Ioana Ionel (Universitatea Politehnica Timisoara, Timisoara,

Romania) Dejan Ivezić (University of Belgrade, Belgrade, Serbia) Thorsten Jänisch (Fraunhofer ICT, Pfinztal, Germany) Sonia Jerez (University of Murcia, Murcia, Spain) Hervé Jeanmart (Université Catholique de Louvain,

Louvain-la-Neuve, Belgium) Titilayo Jinadu (World Hope Foundation, Abeokuta,

Nigeria) Ana Jung (Physee, Delft, Netherlands) Abbes Kaabi (University of Tunis, Tunis, Tunisia) Arunachala M. Kannan (Arizona State University, Mesa,

USA) Azharul Karim (Queensland University of Technology,

Queensland, Australia) Tomaž Katrašnik (University of Ljubljana, Ljubljana,

Slovenia) Dariusz Kardaś (Institute of Fluid Flow Machinery Polish

Academy of Sciences, Gdańsk, Poland) Hlalefang Khobai (Nelson Mandela Metropolitan

University, Port Elizabeth, South Africa) Fydess Khundi-Mkomba (University of Rwanda, Kigali,

Rwanda) Jacek Kluska (Institute of Fluid Flow Machinery Polish

Academy of Sciences, Gdańsk, Poland) Sunisa Kongprasit (Thaksin University, Phatthalung,

Thailand) Mounir Kouhila (Cadi Ayyad University, Marrakech,

Morocco) Christophis Koroneos (National Technical University of

Athens, Athens, Greece) Jaroslav Kultan (Bratislava University of Economics,

Bratislava, Slovakia) Jakub Kupecki (Institute of Power Engineering - Research

Institute, Warsaw, Poland) Jarosław Krzywański (Jan Długosz University,

Częstochowa, Poland) Benahmed Lamia (University of Tlemcen, Tlemcen,

Algeria) Hamza Lamsyehe (Higher Normal School, Marrakech,

Morocco) Roman Le Goff Latimier (Ecole Normale Supérieure

Rennes, Rennes, France) Pierre Le Roux (Nelson Mandela Metropolitan University,

Port Elizabeth, South Africa) Philippe Laval-Gilly (University of Lorraine, Nancy,

France) Hai-Wen Li (Kyushu University, Fukuoka, Japan) Mooktzeng Lim (University of Canterbury, Christchurch,

New Zealand) Ana Lazarevska (Ss Cyril and Methodius University,

Skopje, Macedonia)




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Mateusz Lisowski (Enetech Sp. z o.o., Kraków, Poland) Eva Loukogeorgaki (Aristotle University of Thessaloniki,

Thessaloniki, Greece) Fengji Luo (University of Sydney, Sydney, Australia) Martin Lyambai (Pan African University, Tlemcen, Algeria) Kimberly Magrini-Bair (National Renewable Energy

Laboratory, Golden, USA) Abdelafattah Mahmoud (University of Liège, Liège,

Belgium) Mostafa Mahrouz (Cadi Ayyad University, Marrakesh,

Morocco) Hasmat Malik (Netaji Subhas Institute of Technology,

Delhi, India) Inmaculada Marqués-Pérez (Polytechnic University of

València, Valencia, Spain) Thibault Martinelle (Université Catholique de Louvain,

Louvain, Belgium) J. Birgitta Martinkauppi (University of Vaasa, Vaasa,

Finland) Claudia Masselli (University of Salerno, Salerno, Italy) Ali Mehmanparast (Cranfield University, Bedford, UK) Rui Melício (University of Évora, Évora, Portugal) Amar Merouani (Mohamed el Bachir el Ibrahimi

University, Bordj Bou Arreridj, Algeria) Antonio Messineo (University of Enna Kore, Enna, Italy) Ana Milanović Pešić (Serbian Academy of Sciences and

Arts, Belgrade, Serbia) Jarosław Milewski (Warsaw University of Technology,

Warsaw, Poland) Alina A. Minea (Technical University “Gh. Asachi”, Iasi,

Romania) Safa Mghazli (Cadi Ayyad University, Marrakesh, Morocco) Daniela Mladenovska (JSC Macedonian Power Plants,

Skopje, Macedonia) David Moreno Rangel (University of Seville, Seville,

Spain) Cinzia Mortarino (University of Padova, Padova, Italy) Zineb Mostefaoui (Université Abou Bekr Belkaid,

Tlemcen, Algeria) Omar Mounkachi (Institute of Nanomaterials and

Nanotechnology (MAScIR), Rabat, Morocco) Haytem Moussaoui (Cadi Ayyad University, Marrakesh,

Morocco) Peteer Muiste (Estonian University of Life Sciences, Tartu,

Estonia) Taib Mustapha (Ecole Superieur en Genie Electrique et

Energetique, Oran, Algeria) Bouchra Nabil (Cadi Ayyad University, Marrakesh,

Morocco) Irene Nantongo (Pan African University, Tlemcen, Algeria) Gregory Neubourg (APERe, Brussels, Belgium) Abdul-Sattar Nizami (Center of Excellence in

Environmental Studies (CEES), Jeddah, Saudi Arabia) Ambe J. Njoh (University of South Florida, Tampa, USA) Cirilo Nolasco-Hipolito (University of Malaysia,

Sarawak, Malaysia) Chukwuemeka Obiakor (Covenant University, Ota,

Nigeria)

Michael S. Okundamiya (Ambrose Alli University,

Ekpoma, Nigeria) Judit Oláh (University of Debrecen, Debrecen, Hungary) Eduardo de Oliveira Fernandes (University of Porto,

Porto, Portugal) Noshin Omar (Vrije Universiteit Brussel, Brussels, Belgium) Salvador Ordóñez (University of Oviedo, Oviedo, Spain) Rachida Ouaabou (Cadi Ayyad University, Marrakesh,

Morocco) Ahmet N. Özsezen (Kocaeli University, Izmit, Turkey) María Pablo-Romero Gil-Delgado (University of

Seville, Seville, Spain) Rodrigo Palacios Saldaña (Monterrey Institute of

Technology and Higher Education, Monterrey, Mexico) Mukesh Pandey (State Technological University of MP,

Bhopal, India) Deepak Pant (Flemish Institute for Technological Research

(VITO), Mol, Belgium) Davide Papurello (Politecnico di Torino, Torino, Italy) Florentina Paraschiv (NTNU, Trondheim, Norway) Linnar Pärn (Estonian University of Life Sciences, Tartu,

Estonia) Anélie Pétrissans (University of Lorraine, Vandoeuvre-lès-

Nancy, France) Jan Pieter (Solar Monkey, Delft, Netherlands) Andreas Poullikkas (Cyprus Energy Regulatory Authority,

Nicosia, Cyprus) Cristina Prieto Ríos (Abengoa, Seville, Spain) Lydia Rachbauer (Bioenergy 2020+, Graz, Austria) Bijan Rahmani (Industrial Park of Innovation, Xiangtan,

China) P. Raja (National Institute of Technology, Tiruchirappalli,

India) K. Kalyan Ray (TKR College of Engineering, Hyderabad,

India) Arbo Reino (Tallinn University of Technology, Tallinn,

Estonia) Luis M. Romeo (University of Zaragoza, Zaragoza, Spain) Marco Rosa-Clot (Koine Multimedia, Pisa, Italy) Michel Rwema (Pan African University, Tlemcen, Algeria) Jacinto Sá (Uppsala University, Uppsala, Sweden; Peacock

Solar Power, Uppsala, Sweden) Zafar Said (University of Sharjah, Sharjah, UAE) Ramani Sankaranarayanan (CTx GREEN, Kitchener,

Canada) Antonio Santos Sánchez (Federal University of Ouro

Preto, Ouro Preto, Brazil) Saqib Sajjad (ADNOC Gas Processing, Abu Dhabi, UAE) Mohamed Salah (Université de Tunis, Tunis, Tunisia) Mohammad Salim Zahangir (University of Padova,

Padova, Italy) Tine Seljak (University of Ljubljana, Ljubljana, Slovenia) Mohammed M. Shabat (Islamic University of Gaza,

Gaza, Palestine) Muhammad Shahzad (King Abdullah University of

Science and Technology, Thuwal, Saudi Arabia)




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Ram Vinoy Sharma (National Institute of Technology

Jamshedpur, Jamshedpur, India) Ki-Yeol Shin (Yeungnam University, Gyeongbuk, South

Korea) Pierluigi Siano (University of Salerno, Salerno, Italy) Jean Paul Sibomana (Pan African University, Tlemcen,

Algeria) Mikhail Simonov (Instituto Superiore Mario Boella, Turin,

Italy) Bhaskar Singh (Central University of Jharkhand, Ranchi-

Jharkhand, India) Sunil K. Singal (Indian Institute of Technology Roorkee,

Roorkee, India) Saeed Solaymani (Arak University, Arak, Iran) Vipan Kumar Sohpal (Beant College of Engineering &

Technology, Gurdaspur, India) Michael Sony (Namibia University of Science and

Technology, Windhoek, Namibia) José Fernandes De Sousa (Universidade Federal do

Tocantins, Palmas, Brazil) K.J. Sreekanth (Kuwait Institute for Scientific Research

(KISR), Safat, Kuwait) Aryasomayajula Subrahmanyam (Indian Institute of

Technology Madras, Chennai, India) Maciej Świerczynski (Aalborg University, Aalborg,

Denmark) M. Reza Tabar (University of Oldenburg, Oldenburg,

Germany) Fouzi Tabet (DBFZ, Leipzig, Germany) Mohamed Tawfik (Cranfield University, Bedford, UK) Stella Tsani (Athens University of Economics and Business,

Athens, Greece)

Panagiotis Tsiakaras (University of Thessaly, Thessaly,

Greece) Dimitra G. Vagiona (Aristotle University of Thessaloniki,

Thessaloniki, Greece) Geeta Vaidyanathan (CTx GREEN, Kitchener, Canada) Amir Valibeygi (University of California, San Diego, USA) François Vallée (University of Mons, Mons, Belgium) Stefan P.P. Vanbeveren (University of Antwerp,

Antwerp, Belgium) Gennady Varlamov (National Technical University of

Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine) Alberto Varone (CRS4, Sardegna, Italy) Gláucia E.G. Vieira (Federal University of Tocantis,

Palmas, Brazil) Rosaria Volpe (University of Catania, Catania, Italy) Tadeusz Uhl (AGH, Kraków, Poland) Magdalena Walczak (Pontificia Universidad Católica de

Chile, Santiago, Chile) Xavier A. Walter (University of the West of England,

Bristol, UK) Bingqing Wei (University of Delaware, Newark, USA) Sebastian Werle (Silesian University of Technology,

Gliwice, Poland) Jun Xu (Nanjing University, Nanjing, China) Hakan Yavuz (Çukurova University, Adana, Turkey) Timothy M. Young (The University of Tennessee,

Knoxville, USA) Talal Yusaf (University of Southern Queensland,

Toowoomba, Australia) Sebastian Zapata Ramirez (Universidad Nacional de

Colombia, Colombia) Ahmed Zobaa (Brunel University London, London, UK)




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Organising Committee Wojciech Budzianowski - Chair Witold Surmanek Julia Peterson

Publisher Wojciech Budzianowski Consulting Services

Editors Wojciech Budzianowski

ISBN 978-83-948507-6-0

Copyright ©2019 by Wojciech Budzianowski Consulting Services. All rights reserved. The material is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction in any physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Permission of the publisher is required for photocopying, derivative works and electronic storage or usage. The publisher, the editors and the authors are safe to assume that the advice and information in this material are believed to be true and accurate at the date of publication. Neither the publisher nor the editors or the authors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made.




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Scope

The Renewable Energy Sources - Research and Business (RESRB) conference is designed as a platform for reporting, discussing, improving and disseminating recent developments in renewable energy science, technology, business and policy. Participants from various organisations such as universities, institutes, NGOs, associations, industries etc. are invited. It is an international event with ambitions to share leading research expertise and facilitate business development and thus to be one of the most influential renewable energy knowledge transfer channels. The conference is a must for research groups at the cutting edge of renewable energy science, technology, policy and business development. The conference through its unique research & business model will facilitate synergies between academia and commercial sectors. Delegates from enterprises seeking innovations and expanding to new markets may benefit from sponsoring, exhibiting and networking thus improving their business environment. RESRB is particularly focused on countries applying green growth policies and plays the role in informing policymaking processes. The participation mode can be either in-person or virtual. Publication will be on Book of Abstracts, Proceedings, journals, edited books and books.




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Themes

The 4th RESRB 2019 conference focuses on five key renewable energy areas: (1) bioenergy, (2) wind, (3) solar, (4) hydro and their (5) business development. The special theme for the 4th RESRB 2019 is: • Innovation Driven Renewable Energy Development Other main themes are: • Renewable Energy Harvesting Technologies • Renewable Energy Economics, Business, Policy and Management • Innovation in Renewable Energy Projects Additional RESRB themes include: Solar photovoltaics Wind Hydro Solar thermal Concentrated solar power Geothermal energy Wave, tide and other marine

energies Biofuels Heat pumps Renewable heating and cooling Renewables in transport Renewables in buildings Agricultural and land use issues Biomass production Agronomy Biorefineries Renewables in industrial

symbiosis Energy systems Road maps Hydrogen and fuel cells Power system, power

electronics, smart grid Technologies involving

renewable energy: e.g. food drying, irrigation, desalination

Software tools Environmental impact Life cycle assessment

Decarbonisation and synergies with fossil fuels

Sustainability Standards Infrastructure Materials Resources Power system, power

electronics, smart grid Micro scale renewables Power grids, requirements,

international connections Grid stability, power generation

flexibility Electric vehicles Energy storage Renewables in developed,

developing and underdeveloped countries

Business models and strategies Planning Renewable energy policy Renewable energy economics Renewable energy business

development Innovations, intellectual property

rights Financing, project finance and

management Accounting




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Venture capital, entrepreneurial finance, corporate finance

Intellectual property, start-ups, licensing

Merger and acquisitions, capital markets, outsourcing, consumer behaviour

Incentives, legislation Energy markets Risks and risk management Costs and revenues

Legislative and ethical considerations for research, business and policy interactions

Societal issues, consumer access, social benefits

Organisations Other topics of critical

importance for the development of renewable energy science, technology, policy and business




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Preface

The 4th RESRB 2019 conference aims at disseminating the recent progress in most important areas of renewable energy research, business and policy. This fourth edition brings together participants delivering 46 abstracts published on Book of Abstracts. Renewable energy sources (RESs) are enormous and widely available in the world. Harvesting renewable energy (RE) and providing it to the society has the potential to accelerate sustainable economic growth and reduce poverty. In recent years several RE technologies became competitive in energy markets and can be implement without or with insignificant subsidies. This created market pull that will accelerate energy transition. In recent years major investments in RESs took place in countries where capital was available and not in countries which had potential towards RESs. However, investments in developing countries now also accelerate emphasising that transition to RESs has a truly global character. The characteristic feature of RESs that contrasts with fossil fuels is that the RES cannot be easily economically controlled, because it is in a distributed way available in nature. This fact immensely affects the economics of RESs. Renewable energy business is therefore very specific and this conference attempts to explore it from different angles. Renewable energy economics is more inclusive, compared to fossil fuel economics. Given that RESs are evenly distributed across developed and underdeveloped regions, they are essential for achieving sustainable economic development in all regions. Renewables can mitigate atmospheric greenhouse effect and global warming and be a catalyst for economic growth, thereby achieving energy, economic and environmental sustainability. Since RESs are evenly distributed and thus strongly interact with societies, not only technology is essential for its harvesting, but also social aspects are extremely relevant. Consequently, interdisciplinary character of RESRB helps to explore how to optimally use solar, wind, biomass and hydro energies within technical and social contexts. Research in academia and in companies can play an important role in order to develop innovative technological solutions, that deepen the reduction of costs observed in recent years. Research is required to improve project technical, economic and environmental performance as well as provide societal skills to maximise benefits and impacts. Business development directed at capturing the value of RESs is also essential. Businesses relying on RESs require dedicated innovative business models catalysing cute-edge technologies created inside academia into the real world. It is therefore a lot of space for scientific progress for RESRB conferences.




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Given the rising share of RESs, mostly solar and wind, and the ambition of the EU to reach 100% of RES in energy consumption by 2050, an increasing mismatch appears between supply and demand. One of the keys to unlock the massive adoption of RESs is energy storage. It prevents curtailment of overcapacity and compensates the lack of production due to intermittent character of RESs. Although many studies focus on energy storage, the paradigm needs to be shifted towards a versatile and robust energy generation and storage. Overall, we need smart energy systems that enable to maximise the benfits of RESs and this conference is a platform where technology, business and policy perspectives can meet and interact facilitating the creation of optimal energy systems. Two RESRB 2019 presentations were highlighted as keynote lectures. The keynote lectures addressed some of the essential research, business and policy aspects of RESs. In addition, many interesting oral lectures and short communications were presented and well received by the RESRB audience. The ISC and SAB meeting informed on conference publication models such as internal reviews, journals, edited books and books as well as discussed possible improvements in the organisation of future editions of RESRB conferences such as enabling access to slides and video materials via the conference website. Panel discussion was dedicated to commercialisation of innovative renewable energy technologies. Discussions related to various important commercialisation issues. For instance, technology demonstration in operational environment (large-scale, close to market conditions, etc.) was stressed as one of major issues capable of attracting investors. It was suggested that a large private investor always selects only best options available to him while another investor may at the same time select different options which means that for successful commercialisation investment options need to be considered by many potential investors. Effectiveness of patenting as a route to commercialisation was addressed. Also commercialisation by means of capital investment, organic growth and seeding grants were compared. Finally, benefits arising from advertising at thematic events and conferences facilitating networking and closer interactions especially between inventors and investors were emphasised. Award Committee decided to announce the following Awards at RESRB 2019: (1) Best conference oral lecture - (2) Best conference lecture by student - The winners are invited as keynote lecturers to one of future editions of RESRB conference. W. Budzianowski




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CONTENTS A comprehensive valuation framework for grid-scale storage technologies Kourosh Malek, Jatin Nathwani A new form of decentralized energy: lessons from the WiseGRID project Rafael Leal-Arcas Impact of renewable energy on the environmental efficiency of electric vehicles Rosen Ivanov, Ivan Evtimov, Donka Ivanova, Gergana Staneva, Georgi Kadikyanov, Milen Sapundjiev Ni/CexKIT-6, Ru/CexKIT-6 and Ni-Ru/CexKIT-6 catalysts for the dry reforming of methane: a comparative study Rita Mahfouz, Samer Aouad, Cedric Gennequin, Jane Estephane, Antoine Aboukaïs, Edmond Abi-Aad Modelling biogas production from a closed solid waste landfill in Jordan Hani Abu Qdais, Fayez Abdulla, Rasha Qdaisat An expert-based technology evaluation for assessing the potential contribution of energy technologies to Italy’s decarbonisation path Elena De Luca, Alessandro Zini, Oscar Amerighi, Gaetano Coletta, Maria Grazia Oteri, Laura Gaetana Giuffrida New empirical production models for poplar plantations on farmland - a toolbox for improved management and planning operations Birger Hjelm, Tord Johansson Infrastructure assessment through solar energy harvesting K. Wayne Lee, Austin DeCotis, David Schumacher, Sze Yang Assessing social acceptance of wind energy through policy comparative analysis Cecilia Nardi, Marina Penna, Laura Gaetana Giuffrida, Elena De Luca Energetic, exergetic, environmental and economic comparison between series and parallel schemes of hybrid solar gas turbines Sofía Rodríguez Pita, Javier Rodríguez Martin, Celina González Fernández, Susana Sánchez-Orgaz, Ignacio López Paniagua Time-dependent model of solar thermoelectric generators for enhancing conversion efficiency An-Chi Wei, Mu-Wen Lin, Jyh-Rou Sze Modelling of automatic generation control for multi-area integrated power system equipment including renewable energy systems M. Furkan Yılmaz, Haluk Gözde, M. Cengiz Taplamacıoğlu, Mehmet Karakaya Energetic and economic comparison of agricultural biogas plants feed with silage and food waste Jacek Dach, Wojciech Czekała, Patrycja Pochwatka, Isaias Emilio Paulino do Carmo, Alina Kowalczyk-Juśko, Jakub Pulka Evaluation of the influence of three microbial strains in the composition of the biol obtained from the treatment of textile industry waste Villavicencio-Muñoz N, Barreda-Del-Carpio J, Cárdenas-Herrera L, Garate-Manrique R, Moscoso- Apaza G, Villanueva-Salas J Kinetics of biomethane formation during multi-co-fermentation of organic waste from food industry Sylwia Stegenta-Dąbrowska, Paula Żak, Hubert Prask, Małgorzata Fugol, Agnieszka Medyńska-Juraszek, Bogusław Dulian, Andrzej Białowiec Increased energy efficiency and renewable energy use for high temperature heating Danijela Urbancl, Jurij Krope, Darko Goričanec Photovoltaics design and synergy with landscape: multifunctional land use nexus between renewable energy production and water supply




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Teodoro Semeraro, Alessandro Pomes, Amilcare Barca, Cecilia Del Giudice, Marcello Lenucci, Roberta Aretano, Alessandra Scognamiglio Experimental research and simulation of computer processes of heat exchange in a heat exchanger working on the basis of the principle of heat pipes for the purpose of heat transfer from the ground Łukasz Adrian, Szymon Szufa, Piotr Piersa, Krystian Kurowski Real biogas analysis and energetic valorisation by catalytic reforming Muriel Chaghouri, Sara Hany, Cédric Gennequin, Fabrice Cazier, Catherine Rafin, Etienne Veignie, Edmond Abi Aad The possibility of gaining profit on a rational management of digestate Wojciech Czekała, Patrycja Pochwatka, Jakub Pulka, Jakub Mazurkiewicz, Damian Janczak, Mo Zhou Comparison of the spatial distribution of agricultural biogas plants in relation to generated power Patrycja Pochwatka, Jacek Dach, Jakub Pulka, Wojciech Czekała Determination of the optimal water intake locations for a salinity gradient energy plant on a stratified river mouth using hydrodynamic modelling Jacobo M. Salamanca, Oscar Álvarez-Silva, Aldemar Higgins, Fernando Tadeo Co-gasification of coal and municipal sewage sludge to produce methanol Danijela Urbancl, Marko Agrež, Jurij Krope, Darko Goričanec Production of biogas in a dry anaerobic digestion reactor of residues generated in the processing of sheep and alpaca wool Salamanca-Valdivia M, Cardenas-Herrera L, Barreda-Del-Carpio J, Munive-Talavera C, Garate-Manrique R, Moscoso-Apaza G, Villanueva-Salas J The impact of biowaste pasteurization on the methane yield in the fermentation process Jakub Pulka, Jakub Mazurkiewicz, Wojciech Czekała, Patrycja Pochwatka, Marta Cieślik, Filip Tarkowski, Jacek Dach Zero Waste Egg Production: modeling of valorization of poultry manure Andrzej Białowiec, Ewa Syguła, Piotr Manczarski, Jacek A. Koziel Alternative designs on liquid-flow window technology Tin-Tai Chow, Wenjie Liu Renewable energy resources for better economics and sustainable living in rural and desert areas Karl Gatterer, Salah Arafa Efficiency modelling of a complex planetary mechanical transmission used in renewable energy systems Mircea Neagoe, Radu Saulescu, Codruta Jaliu A study of the reliability of Medina date palm parts as thermal insulator in buildings Khaled S. AlQdah, Raed Alahmdi, Abdurrahman Almoghamisi, Abdurrahman Alanssari, Mohanad Abualkhair, Abdullmajeed Alhazmy, Nasser Alnuman Low carbon Arctic smart community: the ultimate case study of an Arctic renewable energy perspective Gisele M. Arruda A logistic regression approach to model the willingness of homeowners to adopt sustainable energy technologies in different countries Diana Londoño-Pulgarin, Gabriel Agudelo-Viana, Francisco Muñoz-Leiva, Esmeralda Crespo Construction and evaluation of a dry anaerobic digestion reactor for the degradation of solid waste from the textile industry with the use of fungal keratinolytic strains Munive-Talavera C, Barreda-Del-Carpio J, Salamanca-Valdivia M, Cardenas-Herrera L, Garate-Manrique R, Moscoso-Apaza G, Villanueva-Salas J




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SELECTED PAPERS

A comprehensive valuation framework for grid-scale storage technologies Kourosh Malek1,*, Jatin Nathwani1 1Waterloo Institute of Sustainable Energy (WISE), University of Waterloo, Waterloo, ON, Canada N2L 3G1; *corresponding author email: [email protected] Abstract The complexity of adopting grid-scale energy storage (ES) can be attributed to the wide variety of technology choices, diverse application services along the electricity value chain, lack of understanding business models at utility and end user side, and complicated ownership or revenue structures which make the choice of appropriate storage technology difficult. Building upon existing valuation tools and a novel typology of business models for adopting grid-scale storage technologies, this article introduces a practical framework that supports cost-effectiveness of ES use cases by performing detailed cost-benefit and business model analyses. Specifically, we assess the value of ES for a range of grid services under different electricity market structures. A generalized cost-benefit approach for evaluating ES technologies is used to assess storage requirements and value originating from the location-specific needs of grid operators and planners. Moreover, the valuation model identifies monetization and cost-benefit ratios of relevant grid services, where various business models such as utility-side and service contracted models are examined in detail. Keywords Energy storage; business model; techno-economics; renewable energy; value analysis Introduction One of the main road-blocks for wide adoption of renewables in electricity grid operation is associated with their intermittency of providing primary energy sources. As versatile technological solutions, energy storage technologies can provide valuable flexibility to the grid by increasing the utilization of renewable-based electricity assets. Best-practices and reliable business models are essential to enhance storage asset utilization, sustained monetization, and overall reliability of the power systems. The latter is particularly critical for the long-term regional energy policies of implementing renewable sources (Rao and Rubin, 2002; IEA, 2014). Despite significant research, development and demonstration of grid-scale storage technologies in the recent years, there is still a lack of practical frameworks to quantify their economic benefits from planning, technology

valuation, installation, demonstration, and full commercial operation.

This article introduces a practical framework that is ultimately able to evaluate and map suitable business models to the financial benefit of a given storage technology by considering the asset ownership, electricity market structure, and physical location of the storage asset in the electrical grid. Overview of business models All significant cost and revenue streams should be accounted for in the design of the appropriate market and business models. Business models are evaluated in terms of scale and storage type. The business model is defined as a strategies guideline that constructs the “organizational and financial architecture of the firm”. It is the way that firms deliver value and create profit from any purchases. The latter concept of business




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models is fully appropriate for deployment and commercialization of renewable energy sources. The opportunities and barriers of business model innovation are of vital importance for clean energy industry due to the extensive presence of disruptive innovations. The gap illustrated in Figure 1 implies the lack of suitable business models for distributed electricity generations such as energy storage technologies.

Figure 1. Two generic utility business models and their position along value chain, adapted from (Richter, 2012). Business models for energy storage systems In a recent study (He et al., 2011), a new business model that aggregates multiple revenue streams of storage. The model, also referred to as “Benefits-stacking”, consists of multiple ways to utilize the storage unit at different time intervals. A suitable business model framework contains three main attributes, based on which each business model is characterized. The attributes include ownership which describes who takes the risk of construction and operation for the installation of large-scale storage systems; commercial operation which identifies the entity who is managing the risk of monetizing and capturing the value of storage; and market which describes the relevant market structure to which the operator or owner provides storage services. Typology of business models for grid-scale storage Based on the above arguments, we have proposed four types of business models namely utility-side, service contracted, IPP-side, and end-user side models. These groups are characterized by storage asset maturity level and risk profile. These four groups of

business models have distinct characteristics that are impacted by ownership, commercial operation, application, revenue value stream, market structure, asset maturity level, and the flexibility of business models to adapt to various locations or market structures.

As an example, the service contracted model requires high capital investment and is generally viable in the long-term. The success with this business model is relying on rigorous partnership with private technology vendors, utilities, and Independent Power Producers (IPPs). This model implies the involvement of energy storage operator as a project partner and divides the risk and return between the asset operator, public, and private partners equally. This model can be well adopted by regional storage asset operators for future project opportunities within most regions in North America or beyond. Conclusions In order to create profits from storage assets, practical business models can be classified in one of the two categories (i) those which are adopted from general business models for utilities, smart grids, or renewables; and (ii) those which are specific to storage systems with particular considerations for operation, ownership and revenue streams. The existing business models suggest monetization paths based on maturity and suitability of the storage technology for specific market and use cases. Our business model framework and a test case study indicated that the most viable business model for adopting storage technologies on the utility-side could be based on a “service contracted” model, which include both “technology enabling” and “operation” services. The core business model consists of contracts with private and public partners. Acknowledgments Support from Waterloo Institute of Sustainable Energy (WISE) is gratefully acknowledged. References Rao A. B., Rubin E. S., A Technical, Economic, and Environmental Assessment of Amine-




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Based CO2 Capture Technology for Power Plant Greenhouse Gas Control, Environ. Sci. Technol., 2002, 36 (20), pp 4467–4475 IEA, 2014. Technology Roadmap: Energy storage, Available from http://www.iea.org/publications/freepublications/publication/TechnologyRoadmapEnergystorage.pdf (accessed 10.05.14)

Richter M. Utilities’ business models for renewable energy: a review. Renewable and Sustainable Energy Reviews 2012, 16, 248-393. He X.; Delarue E.; D’haeseleer W.; Glachant J.M. A novel business model for aggregating the values of electricity storage, Energy Policy, 2011, 39, 1575-1585.




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A new form of decentralized energy: lessons from the WiseGRID project Rafael Leal-Arcas1,* 1Queen Mary University of London, UK; *corresponding author email: [email protected] Abstract This article provides an analysis of smart grids in the European Union (EU) as a way forward to reach de-centralized sustainable energy. It does so by assessing the energy security, regulatory, as well as social and ethical aspects of smart grids in the EU. The article represents a significant milestone in the up-scaling of the various aspects of smart-grid technology across the EU. It deals with smart-grids deployment and their impact on energy security with a view to a stronger role of prosumers in the energy market. It also analyzes smart grids regulation. The article also assesses the extent to which the existing legal frameworks facilitate the development of smart grids and proposes areas of further regulatory consideration. The article then explores the social and ethical dimension of smart grids in the context of the collaborative economy, the circular economy, and digital technology. Keywords Energy decentralization; energy democratization; digitalization; decarbonization; de-regulation; Introduction This article examines progress on decentralization in several European Union (EU) jurisdictions. It focuses on specific outcomes of decentralization. The article also examines regulation that has helped towards the goal of decentralization in each country, which could perhaps be adopted in other countries seeking to transition to more liberalized energy markets. For the purposes of this article, we focus mainly on electricity markets. Progress on decentralization Europe has been working towards liberalized energy markets since the 1990s, with a series of Directives to this effect (Europarl, 2009). Many member states have made significant progress in this regard, with increased competition amongst energy suppliers, better services, and lower energy prices. Decentralization seems to be the next logical step, as it will further help achieve a more democratic and participative energy market. Belgium started to liberalize electricity at the beginning of the 2000s, in keeping with EU direction. By 2007, the country’s three regions

(the Brussels-Capital region, the Flemish region and the Walloon region) had legally opened their electricity markets. Thereafter, an amendment to the Law of 29 April 1999 was passed. This amendment, the Law of 8 January 2012, strengthened the role of the federal authority (CREG), and made it a separate entity from the Directorate-General for Energy. Additionally, the Constitutional Court decided on 7 August 2013 that the federal level would have sole competence over the application, determination, and exemption of tariffs.

However, the Special Law of 6 January 2014 changed things so that the central government would set transmission tariffs, but regional authorities could establish distribution tariffs. So, Brugel, the VREG and CWaPE are the deciding authorities for setting distribution tariffs in the Brussels-Capital region, the Flemish region and Walloon region, respectively (IEA, 2016). Another shift occurred with the Law of 8 January 2012, which added to regional regulator competences and called for opening competition by unbundling electricity markets (IEA, 2016). In keeping with the new regulation, Belgium’s electricity transmission system operator (TSO), Elia, along with the various distribution system operators (DSOs), unbundled completely from utilities.




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In general, central government regulators handle electricity transmission for systems that have a voltage higher than 72kV, while the regional level has competence over the local distribution and transmission of electricity for systems that have a voltage equal to or less than 70kV. With the exception of offshore wind energy, regional authorities also have competence over renewable energy and over the rational use of energy. Each region has its own regulatory framework for the management of its electricity market: The Ordinance of 19 July 2001 regarding the organization of the electricity market in the Brussels-Capital region; the Decree of 8 May 2009 on energy policy (also known as the Energy Decree) for the Flemish region; and the Decree of 12 April 2001 regarding the organization of the regional electricity market for the Walloon region (Elia Group, 2018).

Reaching a cohesive energy strategy is a key challenge for the country. While currently, Belgium’s central government and its three regions share competence for energy and climate change, in reality the regions enjoy jurisdiction over policy related to these issues. The situation sometimes results in lack of clarity when it comes to dividing competences between the federal and regional levels. Further, the system as it stands leads to a lack of coordination amongst the entities managing energy and climate policies. For effective energy governance, the various state players need to work together in a cohesive and integrated way. To this end, it was decided in 2015, to create an energy pact for the country that would encompass a long-term outlook and to identify tangible steps to achieve energy and climate goals both within Belgium and at the EU level. However, political disagreements got in the way of the project fulfilling its ambitions. In Spain, a process of decentralization has been ongoing since the 1978 Constitution, which officially sealed the country’s shift to a democracy. The Constitution facilitated this decentralization by establishing autonomous regions or “Comunidades Autónomas.” These regions have gained increasing competence, demonstrated by their growing share in total public spending, a fact not necessarily beneficial to the central government. The Constitution allocates some competences

exclusively to the state but the rest are left to the autonomous regions, and most bask in an equal level of political autonomy. The central government has sole competence to authorize electricity networks when their usage impacts another autonomous region or when electricity transmission lines extend further than the relegated territorial allotment. Moreover, the state has the authority to confirm and establish groundwork for mining and energy sectors, which, of course, ties in with the government’s role of planning overall economic activity, in which energy plays a key part. Lastly, the government has the authority to lay down regulation for environmental protection, with autonomous regions having competence to establish accompanying regulations.

Autonomous regions have been claiming authority in residual areas related to energy by making sure to not impinge on the central government’s prerogative. The regions must ensure that any energy policy only affects their region and not any of the others. Furthermore, autonomous regions have sole authority over industry in their regions while complying with overall government frameworks for economic initiatives. Overall, the competences of the autonomous regions must fit within the framework of the central government’s authority on matters related to national security, health or the military, along with sectors confined by regulations on mining, hydrocarbons and nuclear energy.

Overall, autonomous regions play an important part in the country’s energy policy. They have the authority to decide a host of matters connected to national energy policy. For example, they may confirm power plant operations as long as capacity is below 50 megawatts (MW), which applies to the majority of solar and wind plants. Further, autonomous regions can authorize electricity and gas distribution networks within their geographical scope. And they play a key role in deciding and executing policy related to climate change, energy efficiency and renewable energy on the regional front. It is worth exploring links between Spain’s deeply embedded decentralization and the principle of subsidiarity within EU law.

In Italy, there has been a steady move towards liberalization in the country’s




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electricity market since the EU issued its first electricity-related directive (96/92/EC). The EU directive followed the Bersani Decree, which delineated the way forward for liberalizing the market and identified basic tenets for future steps in this direction. Thus far, liberalizing wholesale and retail markets has met with much success. Decentralizing electricity generation and using micro-grids for distribution would be the next major steps. Before the electricity market was liberalized, it was organized as a vertically integrated monopoly, with Enel S.p.A. the main actor in charge. But legislation was passed to promote competition, in order to benefit end consumers. This was achieved by establishing a vertical distinction among companies in a way that distinguishes free activities from competitive ones. In the liberalization process, demand is addressed incrementally, with customers placed into two categories: suitable and eligible. Eligible customers refer to those who signed contracts with particular producers or distributors. The rest are obliged to sign contracts with those producers or distributers servicing their location. Directive 2003/54/EC was the final step in the market being opened completely, from 1 July 2004 for non-residential customers and from 1 July 2007 for residential.

Overall, liberalizing the country’s electricity market has been a legal obligation, in keeping with EU directives and taking place in two phases, broadly speaking: opening markets at a national level and integration of national markets. The grid operator role emerged from the Bersani decree. It is a limited company whose shares are owned by the Ministry of Treasury, Budget and Economic Planning (Enel S.p.A having handed them over for free). The grid operator must provide a public utility service by transmitting and dispatching electricity and managing, in a streamlined way, the high and very high voltage grids. Law No 290/2003 of 27 October 2003 was passed to protect public interests, through unifying the ownership and operation of the network, with the goal of maximizing efficiency and safety. The law delineates the steps for unifying the network’s operation and ownership.

Greece started to liberalize its electricity market in 2001, and the process was finalized in July 2013. However, the state-owned Public Power Corporation (PPC) still has a high level of control over electricity production. Entering the market is challenging due to high levels of capital investment along with licensing processes being plagued by red tape.

Consumers in Greece’s interconnected system have been able to choose their energy supplier since 2004, and residential consumers have been able to do so since July 2007. Since 2016, consumers based in Crete and Rhodes have also had the ability to choose their supplier. However, this right does not extend to consumers based in the smaller, non-interconnected islands, since the PPC is the only available supplier in those isolated microsystems. In this sense, 2007 represents a large step forward for the country’s energy market in terms of being the starting point for its liberalization. The year 2011 stands out as a large amount of supplier changing took place on the retail market. While PPC still held its ground as the main energy provider, a sizeable number of consumers transitioned to alternate providers, demonstrating that there is room for competition to evolve in the retail market.

According to a 2017 report by the Hellenic Electricity Market Operator (LAGIE)—which is in charge of operating and maintaining the country’s energy market—20 companies are registered as energy suppliers and 25 as energy traders, in addition to PPC. However, the majority of suppliers play a greater role in energy trade than in supply. Additionally, seven companies are registered as producers and are recorded in LAGIE’s archives, while some of the producers are also active as suppliers and traders. There is potential for energy retailers and local communities and cooperatives to avail of the WiseGRID application WiseCOOP to more efficiently manage their customers and assets, and also help domestic and small businesses, consumers and prosumers to attain better energy deals. WiseCOOP could help them provide their member or customers with better services and prices, especially in conjunction with demand response programs.

Greece’s natural gas market is also undergoing a process of liberalization, but




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more gradually than the electricity market. In 2011, Law 4001 was established, which provided for separating networks from supply and production activities. The law has undergone numerous modifications since its establishment.

According to Law 4336, passed in 2015, the process of liberalizing the gas market derived from the need to trigger strong competition and lower energy costs. New provisions have since followed, largely related to updating natural gas infrastructure in Greece, the need to legally separate distribution and supply activities, and broadening the eligible customer qualification, which includes electricity customers and several industrial customers. Restrictions related to the supply and monopoly of the Public Gas Corporation of Greece (DEPA) were removed so that public service commissions and large industrial consumers and generators received the right to purchase gas directly from international suppliers.

The opening of the retail market, which started with the industrial sector, continued in 2017 for professional customers, and is to be completed by integrating domestic customers in addition. Many have displayed a keen interest, and by the end of 2016, more than 40 companies had applied for a license to supply gas with the aim of reaching the earliest eligible customers. Opening up the natural gas market can lead to more profitable conditions for the use of CHP. The combination of the WiseGRID STaaS/VPP and WiseCORP applications could be help to integrate CHP systems in the tertiary sector and in industries, to provide a greater incentive to taking part in the energy market, resulting in more services and lowering their overall energy expenses.

Conclusions

Technological advancement is key for a successful decarbonization process, with the aim to provide the highest quality of life with the lowest footprint. The winners of this process are consumers, the environment, and our future. However, technology alone is not enough; we also need the right public policies to reach our decarbonization goals. Smart grids are clearly part of the EU’s future economic, social, and environmental policy landscape. Key strategies on the economy, the environment, and technology provide opportunities for the radical transformation in Europe’s energy infrastructure to take place through smart grids. Acknowledgements This Article has been written with the financial support of the WiseGRID project (grant agreement number 731205), funded by the EU’s Horizon 2020 research and innovation program. The financial help from the Erasmus+ Program of the European Union (EU) is also gratefully acknowledged, which funded my Jean Monnet Chair in EU International Economic Law (project number 575061-EPP-1-2016-1-UK-EPPJMO-CHAIR). References Europarl, 2009; First Energy Package, electricity (1996) and gas (1998); Second Energy Package 2003, and Third Energy Package (2009). See http://www.europarl.europa.eu/factsheets/en/sheet/45/internal-energy-market. IEA, 2016; International Energy Agency, “Energy Policies of IEA Countries. Belgium. 2016 Review,” International Energy Agency, Paris, 2016. Elia Group, 2018; “Legal Framework,” Elia Group, [Online]. Available: http://www.elia.be/en/aboutelia/legal-framework.




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Impact of renewable energy on the environmental efficiency of electric vehicles

Rosen Ivanov1,*, Ivan Evtimov1, Donka Ivanova1, Gergana Staneva1, Georgi Kadikyanov1, Milen Sapundjiev1 1University of Ruse, Ruse, Bulgaria; *corresponding author email: [email protected] Abstract In this paper, an evaluation of the environmental impact of the electric vehicles using energy, produced from different types of power stations is done. The evaluation takes into account the emission factor (CO2 g/kWh) of production of electric energy from renewable energy sources and fossil fuels using existing standards for the life cycle of the vehicles. The original mathematical models and graphical information present the influence of renewable energy on the ecological impact at separate stages of life cycle of the electric vehicles. The use of the renewable energy sources can reduce the emissions from electric vehicles with 20 to 140%, compared to the coal based (lignite) electricity production. Keywords CO2 emissions; BEV Life-Cycle Analysis; electricity; fossil fuels; renewable energy sources Introduction The exploitation of battery electric vehicles (BEV) is related to the use of electrical energy to charge their batteries. This energy is produced in different types of power plants that determine the energy mix of a country. As an alternative to reducing dependence on fossil fuels, the impact of vehicles on the emission of air pollution and their impact on global warming, it is the replacement of the car fleet with electric cars. A large number of studies [1, 2, 3, 4], regarding electric vehicle ecologically efficiency compared to a conventional vehicle (CV), concerning carbon dioxide emissions, have been published. Some studies are focused on the efficiency of primary energy use for life cycle and CO2 emissions associated with the operation of electric vehicles. The researches are incomplete and in a number of cases, contradictory.

The present article regards the contribution of renewable energy to increasing the efficiency of electric vehicles in terms of energy used and CO2 emissions during their entire life cycle for EU-28 countries.

Energy mix and emission factor for EU-28 countries

The energy mix of the member states of the EU-28 and Norway is given in [7, 8, 13]. For the different countries, the share of generated electricity from the main types of power plants such as thermal power plants using coal, nuclear, and renewable energy (RES) is different. Therefore, as an assessment of the impact of the country's energy mix on CO2 emissions in the production of 1 kWh of electricity, the so-called ”emission factor” is used [6] . If the data is analyzed, it can be established that a significant influence on the emission factor has produced energy from NPP and RES. The share of electricity from RES in the final electricity consumption for the E-28 countries in 2017 is shown in [14]. For the means of transport, the share of energy from renewable energy sources is of ecological importance. Тhis share for the EU-28 countries, for 2017 is given on Fig.1 [15]. Effect of the res energy on the CO2 emissions in the production and recycling of electric vehicles The CO2 emissions emitted in the production and recycling of the electric vehicle, excluding




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the battery, can be described with the following relation

(1)

where c is the emission factor in the production of electricity, g/kWh; EPE - the energy required to produce the electric vehicle, kWh; L – life cycle range of the vehicle, km.

Using renewable energy can significantly reduce CO2 emissions from vehicle production and recycling. For example, in Norway with an emission factor of 17 g/kWh, CO2 emissions during the production and recycling of electric vehicles would be reduced by approximately 26 times the EU-28 average emission factor.

Figure 1. Percentage of the used electricity from RES in transport for the E-28 countries in 2017.

Effect of renewable energy on CO2 emissions in the production of BEV’s batteries The performance of electric cars depends mainly on the type of traction battery [3,9]. The air pollution, as equivalent of CO2 emissions, due to the production, transportation, recycling of battery etc., can be represented by the following mathematical model

(2)

where EPB is the specific energy in kWh for the production of a battery with 1 kWh capacity; CB - battery capacity, kWh.

Based on our research, the following average values of energy costs for life cycle of the batteries can be adopted: for Li-ion (Ni-Co) battery - 420 kWh/kWh; for Li-ion (Mn) - 410 kWh/kWh; for Ni-MH-450 and Lead-acid-240 kWh/kWh.

The apparent effect of the electricity source on CO2 air pollution in the manufacture

of rechargeable batteries with a capacity of up to 100 kWh for the whole life cycle of an electric car (290 000 km) is shown in Fig. 2. There is a significantly lower air pollution in battery production using energy from HPP, compared to the production using energy from fossil fuels (lignite) - about 140 times, 65 times in the case of electricity production from wind power plants and 19 times in the case of electricity production from PV plants. For example, to produce 75 kWh Li-ion (Ni-Co) battery, the needed electricity is 30.75 MWh. If this energy is produced from a lignite-fueled TPP, 33.8 tons of CO2 emissions would be generated, which corresponds to 117 g/km emissions during life cycle of the electric car. If renewable energy is used, CO2 emission would be from 0.85 to 6.00 g/km depending on the energy source (HPP, wind or PV power plant). Effect of renewable energy on co2 emissions during the exploitation of electric vehicles The use of renewable energy during the exploitation of electric vehicles influences the CO2 emissions through the electrical energy needed to charge their batteries.

Figure 2. Determination of CO2 emissions from the production of different types of batteries depending on their capacity and the source of electric energy for the life cycle of the electric vehicle.

Emissions of CO2 can be expressed by the equation

kmgEcCO /,10 32

(3)

where E is the specific energy consumption of the BEV, Wh/km.

Fig. 3 shows the possibility of reducing the CO2 emissions during the exploitation of

kmgL

EcCO PE /,1

2

kmgL

CEcCO BPB /,1

2




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the electric vehicle using the energy from RES. For example, at an energy consumption of 210 Wh/km, if we charge the battery only with electricity from a TPP with lignite fuel, CO2 emissions will be 231.0 g/km. If the electricity only from hydro power plants is used, the emissions will be 1.65 g/km. Respectively, use only the electricity from wind power plants generates 57 g/km emissions and electricity from PV plants generates 12.18 g/km.

Figure 3. Determination of CO2 emissions depending on the electric energy consumption of the electric vehicle using different sources of electric energy for charging of its batteries: 1 – hydro power plant; 2 – wind power plant; 3 – PV power plants; 4 – thermal power plants (NG); 5 – thermal power plants (lignite).

Effect of renewable energy on CO2 emissions during the life cycle of BEV Based on (1), (2) and (3), the CO2 emissions can be determined for the whole life cycle of BEV as

kmgEL

CEEcCO BPBPE /,101 3

2

(4)

To determine effectiveness of the use of BEV in comparison with conventional cars, a realistic assessment of the primary energy consumption and the CO2 emission, during life cycle was made. The following assumptions are accepted for the assessment: the same mass of the BEV and the CV; energy consumption of BEV – 0.210 kWh/km; fuel consumption of the CV – 7.6l/100 km gasoline; capacity of the electric car battery - 40 kWh; vehicles life cycle range – 290 000 km; needed energy for manufacturing the vehicle (equal for BEV and

CV), excluding battery – 11 900 kWh [2]; efficiency of NPP – 29.5% [9]; efficiency of TPP (coal) - 26% [10]; efficiency TPP (natural gas fuel) - 40% [11]; efficiency of HPP - 60% [12]; efficiency of WPP - 40%; average efficiency of power plants using RES energy - 50%; losses in transmission and distribution of electricity - 5% [1]; the fuel production– efficiency of process of 79.6% [5].

The results obtained for the primary energy consumed for the life cycle of the BEV and the CV are shown in Fig. 4a. The results represent 4 typical examples – 3 countries and EU, which have very different energy mixes.

a

b

– for production and recycling of the vehicles

– for production and recycling of the battery

– for driving of the vehicles

Figure 4. Life cycle of primary energy (a) and life cycle of СО2 emission (b): BEV-1 – production and driving in Bulgaria; BEV-2 – production and driving with data for EU-28; BEV-3 – production and driving in Norway; BEV-4 – production and driving in Poland; CV – production and driving in Bulgaria.

The generated CO2 emissions for the

life cycle of above-mentioned vehicles are shown in Fig. 4b. The BEV-1 has 59 940 kg of CO2 emissions. It is almost as good as the petrol car CV – 59 750 kg. But the advantage has to be given to an electric car, because it don’t generates harmful emissions where operates – the emissions are emitted where the electricity is produced. The electric vehicle BEV-2 has lower emissions (40 050 kg) compared to BEV-1 by 31%. The minimal value of the CO2




27

emissions has life cycle of the BEV-3 – 1 530 kg, or 39 times less than BEV-1 (as much as CV), 26 times less than BEV-2 and nearly 59 times less than BEV- 4. Compared to a CV produced in the same country, CO2 emissions of BEV-3 are approximately 34 times less (due to lower emissions at the vehicle production stage).

Including new RES to generate electricity, the energy mix of the country and the emission factor respectively change. The effect of this change on CO2 emissions from electric cars can be determined by the equation

(5)

Conclusion From the obtained results, for the effects of replacing the conventional gasoline car fleet with electric vehicles, some conclusions can be drawn.

Using RES to produce electricity can reduce life cycle CO2 emissions of the BEV up to 40 times than the respective of a gasoline CV.

At an emission factor of less than 669 g/kWh, according to the accepted conditions in this study, electric vehicles pollute the environment less than conventional cars. The most effective way to decrease the energy needs and CO2 emissions for life cycle of the BEV is to change the energy mix by using more energy produced by RES and NPP. References 1. D. Bakker. Battery electric vehicles. Performance, CO2 emissions, lifecycle costs and advanced battery technology development. Master thesis Sustainable Development, Energy and Resources, Copernicus institute University of Utrecht, 75 (2010). 2. Aguirre K., L. Eisenhardt, C. Lim, B. Nelson, A. Norring, P. Slowik, N.Tu. Lifecycle Analysis Comparison of a Battery Electric Vehicle and a Conventional Gasoline Vehicle. California Air Resources Board, 33 (2012). 3. J. Brennan, T. Barder, Battery electric vehicles vs. internal combustion engine vehicles. A United States-Based

Comprehensive Assessment, Arthur D. Little, 48 (2016). 4. I. Evtimov, R. Ivanov, G. Kadikyanov. A comparative analysis of the vehicles energy performance, BulTrans-2016, Sozopol (2016). 5. I. Palou-Rivera, J. Han, M. Wang. Updates to petroleum refining and upstream emissions, Center for Transportation Research Argonne National Laboratory, CTR/Argonne, 12 (2011). 6. A. Moro, L. Lonza. Electricity carbon intensity in European Member States: Impacts on GHG emissions of electric vehicles. European Commission, Joint Research Centre (JRC), Italy, Transportation Research Part D (Elsevier, 2017). 7. R. Fischer, E. Elfgren, A. Toffolo. Energy supply potentials in the northern counties of Finland, Norway and Sweden towards sustainable Nordic electricity and heating sectors, Energy Engineering, Luleå University of Technology, Sweden, 31 (2018). 8. S. Skaalbones. Electricity disclosure 2015. Available at: https://www.nve.no/energy-market-andregulation/ retail-market/electricity-disclosure-2015/ 9. O. Eriksson. Nuclear power and resource efficiency – A proposal for a revised primary energy factor, Department of Building, Energy and Environmental Engineering, Faculty of Engineering and Sustainable Development, University of Gävle (2017). 10. A. Scott, R. Wedmaier. The assessment and control of coal damage and loss, Project Number C3017University of Queensland, Available at: www.acarp.com.au/abstracts.aspx?repId=C3017 11. Steam-gas power stations. Energy Review, 3 (2010). 12. Real world hydro power calculation. The Renewable Energy Website. Available at: http://www.reuk.co.uk/wordpress/hydro/calculation-of-hydro-power/ 13. Energy production, 2005 and 2015. Available at: https://ec.europa.eu/eurostat/statistics-explained/index.php?title=File:Energy_production,_2005_and_2015_(million_tonnes_of_oil_equivalent)_YB17.png 14. Share of energy from renewable sources in gross final consumption of energy, 2004-2017 (%).png. Available at:

kgcCO ,00060896862




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https://ec.europa.eu/eurostat/statistics-explained/index.php?title=File:Share_of_energy_from_renewable_sources_in_gross_final_consumption_of_energy,_2004-2017_(%25).png

15. 5-Share of renewable energy sources in transport 2004-2017.png. Available at: https://ec.europa.eu/eurostat/statistics-explained/images/9/9a/Table_5-Share_of_renewable_energy_sources_in_transport_2004-2017.png




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Ni/CexKIT-6, Ru/CexKIT-6 and Ni-Ru/CexKIT-6 catalysts for the dry reforming of methane: a comparative study

Rita Mahfouz1,2,3, Samer Aouad2,*, Cedric Gennequin1, Jane Estephane3, Antoine Aboukaïs1, Edmond Abi-Aad1 1UCEIV, E.A. 4492, Université du Littoral Côte d’Opale, F-59140 Dunkerque, France; 2Department of Chemistry, University of Balamand, Tripoli, Lebanon; 3Department of Chemical Engineering, University of Balamand, Tripoli, Lebanon; *corresponding author email: [email protected] Abstract Dry reforming of methane was studied over the 3 catalysts Ni/CexKIT-6, Ru/CexKIT-6 and bimetallic Ni-Ru/CexKIT-6 (x=0 or 60%) synthesized using the wet impregnation technique. To our knowledge, no studies have considered the usage of such catalytic materials in the DRM reaction. The percent of nickel and ruthenium in all catalysts was fixed at 15 wt% and 1 wt% respectively. All catalysts showed high CH4 conversions comparable to the thermodynamic theoretical values. Ru based catalysts inhibited carbon deposition and favoured DRM. Keywords DRM; KIT-6; cerium; nickel; ruthenium Introduction Nowadays, hydrogen is considered as the most promising energy vector of the future as it is readily available, less polluting, and can be efficiently converted to electricity in fuel cells [1] . Among all chemical processes used to produce hydrogen, the transformation of CO2 with CH4 (Eq. (1)) , which is known as the dry reforming of methane (DRM) attracts attention due to the abundance of these reactants and the feasibility of their transformation towards H2 and/or synthesis gas (syngas) [2].

Moreover, the DRM process is cheaper than other methods as it does not require the complicated gas separation of end products[3].DRM requires a significant amount of energy to operate (endothermic reaction). This is why, for it to be economically feasible, the DRM reaction should be performed in the presence of a catalyst.

CH4 (g)+ CO2(g) ↔ 2H2(g)+ 2CO(g) (1) The presence of both CO2 and H2

generates the simultaneous reverse water gas shift reaction (RWGSR) especially at high reaction temperatures [4] (Eq.(2)).

CO2 (g) + H2 (g) ↔ CO (g) + H2O (g) (2)

In addition to the RWGSR, production of syngas by DRM is also affected by competing side reactions which assist carbon formation and deposition on the surface of the catalyst, for instance methane decomposition (Eq.(3)) and Boudouard reaction (Eq. (4)) [5].

CH4(g) ⇌ C(s) + 2H2(g) (3) 2CO (g) ⇌ C(s) + CO2(g) (4)

Catalyst’s activity and stability is affected by the nature of the support as well as the active phases used. In this work, KIT-6 ordered mesoporous silica was chosen as a catalytic support due to its high specific surface area and very precise pore size distribution [6]. Having its name from the KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY, KIT-6 (molecular formula: SiO2) is famous for providing easy and direct access to the active sites, which facilitates the insertion or diffusion of species in its interior. It was doped with cerium oxide in order to improve its redox properties which in turn improve the interaction of the support with the active phase. Noble metals, such as Rh, Pt, Pd, and Ru are successfully used in DRM ; however, due to their high costs and limited availability, researches has also focused on other cheaper yet more prone to deactivation non noble based metals such as Ni and Co [7] .




30

This work emphasizes the use of the 2 active phases Ni and Ru supported on KIT-6 and on 60 wt% Ce/KIT-6 and compares their performance and resistance to carbon formation in the dry reforming of methane. Methods Catalysts preparation - synthesis of mesoporous KIT-6 silica template and Cerium Oxide-KIT-6 The synthesis of the support KIT-6 was done according to Liu et al [8]. For the synthesis of the mesoporous cerium oxide, siliceous KIT-6 has been used as a template. Therefore, an appropriate amount of Ce(NO3)3•6H2O (Sigma–Aldrich) was dissolved in 20 mL of absolute ethanol. 0.5 g KIT-6 was added to this solution and heated at 60 °C under vigorous stirring. After the ethanol had completely evaporated, the solid was calcined at 450 °C for 4h to remove the nitrate species. Another Ce(NO3)3•6H2O dissolved in ethanol solution was added to the solid in order to achieve higher metal loadings. The powder was dried at 110 °C overnight and calcined at 550 °C (1oC/min) in synthetic air for 4h. Catalysts preparation - synthesis of Ni and Ru based catalysts The wet impregnation technique was used in order to synthesize the following catalysts: Ni/KIT-6, Ru/KIT-6, Ni-Ru/KIT-6, Ni/Ce60KIT-6, Ru/Ce60KIT-6, and Ni-Ru/Ce60KIT-6. DRM Catalytic Test During each test, 100 mg of the catalyst was introduced into a U-shaped fixed-bed quartz reactor. The latter is fed with a gaseous mixture of CH4 / CO2 / Ar (20% / 20%/ 60%) under atmospheric pressure and a CH4 / CO2 molar ratio equal to 1. Before any catalytic reforming test, each catalyst must undergo an activation step which consists of treating it with a reducing mixture of 5% H2 / Ar at 800 ° C for 2 h. The reactor is then cooled to 500 ° C under a stream of argon. The test is then conducted in a temperature range of 500° C to 800 ° C in a

lab-scale set up. Micro-GC analyses of the outlet gases are made every five minutes. Characterization after test Simultaneous thermogravimetry analysis and differential thermal analysis (DTA/TGA) were performed on an SDT Q 600 Instruments. The spent catalysts were heated to 900oC under an air flow of 50 mL/min at a heating rate of 5oC/min. Results Figure 1 and Figure 2 show the methane conversions of the prepared catalysts as a function of temperature. To elaborate more on the carbon deposition phenomena and determine the type of carbon deposited, thermal analysis was performed on the catalysts after DRM. Figure 3 (A and B) shows the simultaneous DTA/TGA curves of the spent catalysts. Discussions According to Figure 1, at all temperature ranges the catalyst Ru/KIT-6 is the catalyst with the minimal CH₄ conversion; however, the catalysts Ni/KIT-6, and Ni-Ru/KIT-6 reveal higher comparable activity that becomes more significant for the bi-metallic catalyst at temperatures greater than 600oC. From Figure 2, we can infer that promoting the catalysts Ru/KIT-6 and Ni/KIT-6 with Ce ameliorated their CH₄ conversions

500 550 600 650 700 750 800

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20

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CH

4 C

on

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ion

(%)

Temperature (oC)

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Ni-Ru/KIT-6

Figure 1. CH₄ conversions of KIT-6 supported catalyst during DRM.




31

500 550 600 650 700 750 800

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Theoretical Conversion

Ru/Ce60KIT-6

Ni/Ce60KIT-6

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(%

)

Temperature (oC)

Figure 2. CH₄ conversions of KIT-6 promoted with Ce supported catalysts during DRM.

On the other hand, Ce addition had no remarkable effect on the catalyst Ni-Ru/KIT-6. This enhanced reactivity is probably attributed to the fact that the incorporation of cerium ions into the walls of KIT-6 allows the creation of acid sites that create a greater flexible network of interaction [9].

From Figure 3 (A and B), both Ru based catalysts (Ru/KIT-6 and Ru/Ce60KIT-6) showed no weight loss attributed to the combustion of carbon which suggests that both catalysts were resistant to carbon formation during the DRM process. On the other hand, the largest weight loss was observed for Ni/Ce60KIT-6 catalyst (∆m=55%). The addition of Ru to Ni slightly decreased carbon formation for the latter (∆m=52%), whereas, in the absence of Ce, the addition of Ru had a more remarkable effect on carbon deposition (decrease by 35%).

100 200 300 400 500 600 700 800

A Ru/KIT-6

Ni/KIT-6

Ni-Ru/KIT-6

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Flo

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mW

)

m

=5%

m

=40%

Weig

ht

Lo

ss (

%)

Temperature (oC)

100 200 300 400 500 600 700 800

m

=55%

B

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mW

)

m

=52%

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ht

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ss (

%)

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Ru/Ce60KIT-6

Ni/Ce60KIT-6

Ni-Ru/Ce60KIT-6

Figure 3. (A): DTA/TGA curves of KIT-6 supported catalysts after DRM. (B): DTA/TGA curves of KIT-6 promoted with Ce supported catalysts after DRM.

Several studies [3], [10] in the

literature report that the role of ruthenium in contact with the active nickel is to keep the surface reduced and decrease the diffusion rate of carbon into the metallic nickel particle. Moreover, it can be inferred from the DTA/TGA curves that Ni/KIT-6 ,Ni/Ce60KIT-6, Ni-Ru/KIT-6, and Ni-Ru/Ce60KIT-6 show a common exothermic peak at around 620℃ which can be attributed to the oxidation of graphitic carbon species [2] . Conclusions • NiCex/KIT-6, RuCex/KIT-6 and Ni-Ru/CexKIT-6 (X=0 or 60%) catalysts were tested in the DRM reaction. • The addition of Ce into KIT-6 increased CH₄ conversions for the monometallic catalysts. • Ru based catalysts showed no carbon formation.




32

• Addition of Ru to Ni inhibited carbon deposition especially in the absence of Ce. • The development of novel catalysts that were able to induce high conversions and inhibit carbon deposition in DRM was successful. Acknowledgments The authors would like to thank the ULCO, the AUF and the Lebanese CNRS for financial supports. References [1] J. Estephane et al., “CO2 reforming of methane over Ni–Co/ZSM5 catalysts. Aging and carbon deposition study,” Int. J. Hydrog. Energy, vol. 40, no. 30, pp. 9201–9208, Aug. 2015. [2] S. S. Itkulova, Y. Y. Nurmakanov, S. K. Kussanova, and Y. A. Boleubayev, “Production of a hydrogen-enriched syngas by combined CO2-steam reforming of methane over Co-based catalysts supported on alumina modified with zirconia,” Catal. Today, vol. 299, pp. 272–279, Jan. 2018. [3] B. Abdullah, N. A. Abd Ghani, and D.-V. N. Vo, “Recent advances in dry reforming of methane over Ni-based catalysts,” J. Clean. Prod., vol. 162, pp. 170–185, Sep. 2017. [4] R.-Y. Chein and W.-H. Hsu, “Thermodynamic analysis of syngas production via chemical looping dry reforming of methane,” Energy, vol. 180, pp. 535–547, Aug. 2019.

[5] D. G. Araiza, D. G. Arcos, A. Gómez-Cortés, and G. Díaz, “Dry reforming of methane over Pt-Ni/CeO2 catalysts: Effect of the metal composition on the stability,” Catal. Today, Jun. 2019. [6] Z. Taherian, M. Yousefpour, M. Tajally, and B. Khoshandam, “Catalytic performance of Samaria-promoted Ni and Co/SBA-15 catalysts for dry reforming of methane,” Int. J. Hydrog. Energy, vol. 42, no. 39, pp. 24811–24822, Sep. 2017. [7] Z. Taherian, M. Yousefpour, M. Tajally, and B. Khoshandam, “A comparative study of ZrO2, Y2O3 and Sm2O3 promoted Ni/SBA-15 catalysts for evaluation of CO2/methane reforming performance,” Int. J. Hydrog. Energy, vol. 42, no. 26, pp. 16408–16420, Jun. 2017. [8] S. Liu et al., “Studies on toluene adsorption performance and hydrophobic property in phenyl functionalized KIT-6,” Chem. Eng. J., vol. 334, pp. 191–197, Feb. 2018. [9] A. Prabhu, L. Kumaresan, M. Palanichamy, and V. Murugesan, “Cerium-incorporated cage-type mesoporous KIT-6 materials: Synthesis, characterization and catalytic applications,” Appl. Catal. Gen., vol. 374, no. 1, pp. 11–17, Feb. 2010. [10] A. D. D. Kaynar, D. Dogu, and N. Yasyerli, “Hydrogen production and coke minimization through reforming of kerosene over bi-metallic ceria–alumina supported Ru–Ni catalysts,” Fuel Process. Technol., vol. 140, pp. 96–103, Dec. 2015.




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Modelling biogas production from a closed solid waste landfill in Jordan Hani Abu Qdais1,*, Fayez Abdulla1, Rasha Qdaisat1 1Jordan University of Science and Technology, Irbid, Jordan; *corresponding author email: [email protected] Abstract The objective of this paper is to assess the amount of biogas generated from the closed landfill of Russaifah (Jordan) using two modelling approaches. The models used in the assessment of biogas are Gasim and LandGem. According to both models, the maximum amount of biogas was reached in the year 2004, one year after the landfill closure. Gasim model gave a maximum landfill gas (LFG) generation amount of about 4204.8 x 103 m3/year, while LandGem model resulted in an amount of 4055.9 x 103 m3/year. The results were validated by comparing with data of methane extraction from the landfill. Results show that GasSim capability to predict the amount of biogas generated is little bit higher than that of LandGem, where coefficient of determination R2 = 0.72 and 0.678 for GasSim and LandGim, respectively. Global warming analysis revealed that until the year 2014, as a result of methane recovery, the landfill has a climate change mitigation potential of 763,000 tons of CO2 Equivalent. Keywords biogas modelling; closed landfill; Russaifah; Jordan; global warming potential Introduction Integrated solid waste management strategies, like waste to energy and composting play a significant role in reducing greenhouse gas (GHG) emissions by recovering energy and materials from the mixed municipal solid waste stream (ISWA, 2009). landfills have been and will continue to be one of the most applied disposal options of municipal solid waste (Abu Qdais et al. 2012). Landfilling process are usually associated with byproducts including landfill biogas. Biogas is generated as a result of anaerobic biodegradation of the organic fraction inside the landfill. Landfill biogas is typically composed of methane (50–60%) and carbon dioxide (40–50%) with some trace gases (Tchobanoglous et al., 1993). It is well known that methane and carbon dioxide are greenhouse gases (GHGs) that cause global warming which leads to climate change phenomena. According to the third national communication report (TNC,2014), the waste sector in Jordan is the second largest contributor of GHGs emissions after the energy

sector. The waste sector is responsible for 10.6% of the total country’s emitted GHGs, where 98.6% of these emissions are caused by the disposal of domestic solid waste. This is a relatively high percentage as compared with the GHGs contribution of the waste sector on the global level of 5% of the total emissions (Abu Qdais et al., 2019). In a country like Jordan, where the energy sources are limited, and the country depending mainly on costly and unsteady supply of imported oil and gas, utilizing the renewable energy sources, such as energy recovery from solid waste is gaining a special importance (Abdulla et al, 2004). In principle models are structured to describe the trend that landfill gas is generated and produced. They are quantitative summaries of the important processes which occur in the system. The LFG are developed either for forecasting the yield and production rate of biogas generated, or to evaluate the potential gas migration and related problems (Abu Qdais et al., 2012). Abu Qdais et al. (2012) modeled the biogas generated from an unsanitary landfill in Jordan using Gassim model. The modeling results were compared




34

with the results of pumping test of methane emissions from two biogas extraction wells excavated on the landfill site. The main objective of this paper is to assess the amount of biogas generated from the closed landfill of Russaifah (Jordan) using Gasim, and LandGem models and comparing the results with the actual methane extraction. Another objective is to assess the climate change mitigation potential through the recovery of methane. Methodology Russaifah landfill used to serve the capital city of Jordan, Amman and some other nearby cities. The landfill designed as an unsanitary one that lacks biogas and leachate management systems. Because of its adverse environmental impacts, Greater Amman Municipality (GAM) decided in 2003 to close it and move to a new sanitary landfill that is located away from urbanized areas. However, the landfill continued to emit gases and unpleasant odors to the nearby residential areas. Therefore, it was decided to build a biogas plant that will extract the biogas from 20 biogas wells excavated on the landfill (first stage) and utilize it for energy production.

Data collected on the amounts and composition of the solid waste disposed in the landfill, as well as the climatic conditions of the site was collected. The data were introduced into the models to compute the amounts of biogas that will be generated. The estimated methane amounts by the models were compared with the actual amounts of methane that extracted from the excavated wells. Models used in the study For the purpose of this study, two models were used. These are Gassim and LandGem models. 1. Gas Simulation Model (Gassim) is a probabilistic multi-phase model that considers the landfill as one unit. The model governing equations are: Ct = C0-(C0,1 e(-k1t) + C0,2e(-k2t)+C0,3e(-k3t))

(1) Cx = Ct - Ct-1 (2) where,

C0, Ct = masses of degradable carbon degraded at the beginning (t = 0) and up to time t (Mg) C0,I = mass of degradable carbon at time t=0 in each fraction (1,2,3,rapidly, moderately and slowly degradable fractions) Cx = Mass of carbon degraded in year t (Mg) t = Time between waste emplacement and LFG generation (yrs) ki = Degradation rate constant for each fraction of degradable carbon (per year) Landfill Generation Energy Model (LandGim) Developed by US EPA as a first order model that determines the mass of methane generated using the methane generation capacity and the mass of carbon deposited.

Qt = 2L0 m0 (ekta – 1)e-kt (3) where Qt = Expected gas generation rate in the tth year, (m3 /yr) L0 = Methane generation potential (m3 /yr) m0 = Constant or average annual solid waste acceptance rate, Mg/yr k = Methane generation rate constant, (per year) t = Age of the landfill (yr) ta = Total active period of the landfill ( yr) Results and discussion Biogas from the closed landfill of Russaifah was assessed using modelling techniques and compared to the real methane amounts that were extracted from the landfill. Figures 1 and 2 show the amount of methane generated using Gassim and Landgim, models respectively. The figures also show the cumulative amounts of solid waste disposed in the landfill until its closure. It can be observed that Gasim model predicts a maximum biogas generation amount of about 4204.8 x 103 m3/year, while modelling using LandGem has resulted in an amount of 4055.9 x 103 m3/year. This indicates that GasSim estimation is greater than LanGim.




35

Figure 1. Landfill gas amount prediction using GasSim.

Figure 2. Landfill gas amount prediction using LandGem.

Models validation was conducted using landfill methane extraction records. Figures 3 and 4 show the simulated versus measured methane amounts for both models. The validation results as judged by the coefficient of determination (R2) show that GasSim capability to predict the amount of biogas generated is little bit higher than that of LandGim, where R2 equals to 0.702 and 0.678 for GasSim and LandGem, respectively. This may be attributed to the fact that GAsSim is a multiphase model that considers the availability of slow, medium and rapidly biodegradable matter within the waste stream, which is not the case with LandGem that does not consider the variability in materials' biodegradability.

Both GasSim and LandGem models developed for sanitary landfills in developed countries (i.e. UK and USA). Applying them to unsanitary landfills like the ones in developing countries which were designed without the provision of biogas system and where the composition of the solid waste is different, involves higher level of uncertainty. In order to minimize the uncertainty level, such models should be tuned to the landfills mode of operation and solid waste composition in developing countries by reflecting that in the models parameters (Sil et al., 2014). Alternatively, new models should be

developed specially for landfills in developing countries, where the local circumstances are all accounted for.

Figure 3. Measured versus simulated methane using GasSim.

Figure 4. Measured versus simulated methane using LandGem.

Greenhouse gas emissions from the landfill were estimated and presented in units of tons of CO2 equivalent. Table 1, shows the amount of methane recovery and its global worming potential. It can be observed that by the year 2002 just before the landfill closure, methane recovery had contributed to mitigate about 57,000 tons of CO2 equivalent, after which the amount has declined and reached in 2014 to about 44,800 tons of CO2 equivalent. Conclusions In this study, methane generation from Russaifah closed landfill were estimated using two models. The following has been concluded: • With better management, landfills can be converted from a source of public nuisance to a source of clean energy. In addition, methane recovery will lead to climate change mitigation, which is the case with Russaifah landfill.

0

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0

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1989 1999 2009 2019 2029 2039

Was

te in

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t

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00

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e (1

00

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3 /Ye

ar)

YearGasSim CH4 Generation (m3/yr)

0

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3500

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4500

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year

)

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36

• GasSim model seems to be of better accuracy than LandGem in predicting methane amounts, as it is a multiphase one that takes into account variations in organic matter biodegradability. • Models are useful tools in assessing the amount of biogas generated from landfills. However, most models emerged from developed countries that do not consider the circumstances in developing countries. This indicates the need to develop new models that accounts for landfills and solid waste characteristics in developing countries. Table 1 Methane recovery from the landfill and its global warming potential.

Year CH4 Reduction 1000 tone/yr

CO2 Equivalent

1000 ton/yr

2000 2.37 49.85

2001 2.55 53.49

2002 2.72 57.05

2003 2.66 55.92

2004 2.61 54.82

2005 2.56 53.73

2006 2.51 52.67

2007 2.46 51.62

2008 2.41 50.6

2009 2.36 49.6

2010 2.32 48.62

2011 2.27 47.65

2012 2.22 46.71

2013 2.18 45.79

2014 2.14 44.88

References

Abdulla F., Widyan M., Ziad Al-Ghazawi Z., Kiwan S., Abu-Qdais H., Hayajneh M., Harb A. and Al-Nimr M. (2004) Status of Jordan renewable energy sector: problems, needs and challenges, Regional Workshop on Renewable Energy, Beirut, Lebanon. Abu Qdais H. A. , Maqableh A. M., Al Nwayseh L.M. and Al Jammal N. (2012) Energetic and methane emission reduction potential from an unsanitary landfill, Energy Sources, Part A, 34: 360–369. Abu Qdais H., Wuensh C., Dornack C. and Nassour A. (2019), The role of solid waste composting in mitigating climate change in Jordan, Waste Management and Research, doi.org/10.1177/0734242X19855. ISWA (2009) International Solid Waste Association (2009) Waste and climate change, ISWA white paper. Available at: https://www.iswa.org/fileadmin/user_upload/_temp_/WEB_ISWA_White_paper.pdf (accessed 25 August 2018) Sil, A., Kumar, S. and Kumar, R. (2014) ‘Formulating LandGem model for estimation of landfill gas under Indian scenario’, Int. J. Environmental Technology and Management, 17: 2 pp.293–299. Tchobanoglous, G., Theisen, H., and Vigil, S. A. (1993) Integrated Solid Waste Management, Engineering Principles and Management Issues. New York: McGraw-Hill. TNC (2014). Ministry of Environment, Third National Jordanian Communication Report to United Nations Framework Convention on Climate Change (UNFCCC), Amman Jordan




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An expert-based technology evaluation for assessing the potential contribution of energy technologies to Italy’s decarbonisation path

Elena De Luca1,*, Alessandro Zini1, Oscar Amerighi1, Gaetano Coletta1, Maria Grazia Oteri1, Laura Gaetana Giuffrida1 1Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA); *corresponding author email: [email protected] Abstract A reference Catalogue on the energy technologies was realised within the framework of the ‘Technical Board on Decarbonisation of the economy’, established by the Italian Presidency of the Council of Ministers. The Catalogue is a tool to support policy makers addressing the issues related to the decarbonisation of the economy, from the viewpoint of balancing the three pillars of a sustainable energy system: environmental sustainability, energy security and energy costs. A standard datasheet containing quantitative and qualitative information on Technology Readiness Level (TRL), efficiency, environmental and economic impact and policy aspects was compiled to provide an evaluation of each technology by the experts involved in each research field. This paper describes the methodological approach and gives a footprint of the development potential in Italy. Keywords Technology Evaluation; Decarbonisation; TRL; Energy Trilemma Introduction The energy sector can contribute to the achievement of the expected objectives of the energy transition through the development of innovative technologies characterised by ecological and economic sustainability.

An accurate technology evaluation should be addressed to the three conditions posed by the so-called energy ‘trilemma’. The concept of energy ‘trilemma’, introduced in 2003 [1], brings out the complexity of balancing the three pillars of a sustainable energy system: decarbonisation, energy security and energy costs [2]. Technology evaluation is an issue widely recognized both in the research and industrial sectors. Actually different indicators and models are currently proposed to technology assessment at different level [3,4]. To this purpose, the Italian Presidency of the Council of Ministers set up in June 2016 a "Technical Board on the Decarbonisation of the Economy" to analyse the energy system from the point of view of various stakeholders and start a technical assessment aimed at shaping Italian policies in the energy-environmental field within the framework of EU regulation.

The Technical Board was attended by representatives of national and local administrations, universities, research institutions and the private sector.

Four Working Groups (WGs) have been established to achieve synergistic and complementary objectives. The Figure 1 captures the relationships between each WG. WGs 1 and 2 have provided the technological and non-technological input used by WG 3 to develop the Baseline National Scenario 2012-2030 [5]. WG 4 has performed cost-benefit analysis of the several decarbonisation scenarios. Decarbonisation cannot be achieved without a careful techno-economic analysis of energy technologies. Such technologies may significantly contribute to the environment protection standards; thus, their development should be accelerated by adequate incentives.

Figure 1. Working Groups (WGs) of the Technical Panel for Decarbonisation of the Economy. WG1: Non




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technological input; WG2: Technological Input; WG3: Scenarios; WG4: Evaluation Board

The “Catalogue of Energy Technologies” [6], realised within the framework of WG2 activities, is aimed to provide information that is reliable, well documented and replicable, on the status of the technologies and their potential penetration in the energy market. This paper describes the methodological approach followed to provide an evaluation scheme for each technology considering different parameters. In order to give a footprint of the development potential in Italy, some relevant data contained in the Catalogue were analysed and elaborated by a statistical approach. The analysis highlights peculiarities and issues related to the Italian energy sector and suggests strategies to support research and/or the domestic production chain. Methods Technology evaluation The Catalogue is a result of a dialogue among 70 experts who have set up a standard datasheet for technology evaluation. Technologies with different Technology Readiness Level (TRL) are described considering the wide range of industrial configurations with potential of decarbonisation starting from those available in the market (TRL=9) up to the emerging technologies characterised by low TRL (TRL =2). 36 technologies have been identified and grouped into six different categories: Generation Technologies with fossil sources, Co-Generation Systems, Renewable Energy Technologies, Energy Storage Systems, Energy Efficient Technologies and Crosscutting Technologies. Analysis tools and assessments In order to draw the potential development of the energy technologies in Italy, some quantitative analyses have been carried out. The data matrices of TRL, CO2/MWh avoided emissions, the number of Italian companies involved in development of technology and Research Excellence Units have been

elaborated by statistical tools. Cluster Analysis was performed by R software [7,8] to find relations between TRL and the number companies involved in energy technologies, thus highlighting emerging groups of technologies. The relation between TRL (medium value and range) and CO2 avoided emissions has been displayed by a Scatter Plot diagram. The mapping of the distribution of Local Units of Italian companies involved in development of technology and Research Excellence Units by region has been realised by the Free Open Source Software (FOSS) QGIS [9]. Results and discussion The range between the minimum and maximum values of TRL detected was recorded for each technology. Such information should be considered as a proxy of the potential development of technologies. In the case of a narrow range between 8 and 9, further innovation will be very limited. Instead, in the case of a wide range of TRL (2 to 9), even if some products are already available on the market, the technologies involved have a substantial margin of innovation, especially in component development, which may lead to increase efficiency and/or economic/environmental sustainability. In the case of low TRL, with a very narrow range, the involved technologies need additional efforts in research in order to enter the market. Cluster analysis on the values of the TRL range and the number of entities involved in production and use of technologies, shows the potential for development and the participation of the Italian Industries. Although the number of companies involved in a given technology depends on specific sectoral characteristics, such as capital intensity and the consequent barriers to entry, the representation that returns seems rather congruent on the technological and commercial level. Three clusters are identified (Figure 2): • Cluster A groups technologies with product innovation content; • Cluster B groups technologies with process innovation;




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• Cluster C groups innovative technologies with high degree of diffusion.

Figure 2. Cluster analysis performed on TRL data and number of companies involved in production and use of technologies

The impact on climate is an important

issue in evaluating technology. In order to assess the potential of innovation as a function of technology readiness and reduction of greenhouse emissions, the data on TRL and the quantity of avoided CO2 are compared. In the scatter plot (not shown), four quadrants sort the various technologies into four categories. Quadrant II groups technologies that look interesting in terms of their high potential to reduce CO2 emissions and that are also characterized by a large development potential. Renewable Energy Sources (RES) technologies and Energy Storage Systems are well represented in this quadrant. The maximum effort of technological development at the national level should be made in these sectors. In particular, Solar Thermodynamic seems the most promising technology, due to its growth potential and its good decarbonisation level. Photovoltaic technologies, both traditional and solar concentration based, belong to this quadrant

too. Geothermal and Anaerobic Biomass Digestion seem close to the other RES technologies of this quadrant, but with a slightly smaller margin of growth. As expected, all Cogeneration and Energy Storage system fall in Quadrant III, characterized by medium capacity of CO2 emissions reduction and high potential development. As in the previous case, (i.e. Quadrant II), these technologies could be implemented through a support strategy for research and development. Conversely, Quadrant I groups technologies with a medium-high degree of TRL and a high potential of CO2 reduction with a narrow range of TRL which seem the result of a longer technological-commercial process. For two technologies belonging to the group Generation Technologies with fossil sources this process is still uncompleted (Oxifuels plant of coal with Carbon Capture System and Integrated Gasification Combined Cycle of coal with carbon capture system). Finally, Quadrant IV, including high maturity and relatively lower decarbonisation impact technologies, seems the most composite, since it groups RES, Generation Technologies with fossil sources and Energy Efficient technologies. As for the mature technologies of Quadrant I, these technologies show a narrow range of TRL; as such, efforts at the national level should be oriented to sustain the market penetration of these technologies by supporting the domestic production chain.

The maps of the Local Units of Italian companies involved in development of technology and the Research Excellence Units show a territorial distribution that is not completely homogeneous. Companies are located mainly in the North side of the country (Figure 3a). The Regions with the highest number of local units of companies involved in development of technology are Piedmont, Lombardy, Veneto, and Emilia Romagna, typically the most industrialized Regions of Italy. Tuscany, Latium, Apulia and Sicily show medium-high number of units (41-62).




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Figure 3. Mapping of the number of local units of Local Units of Italian companies involved in development of technology (a) and Research Excellence Units (b)

Liguria, Marche, Abruzzo and Campania have a medium number of units (21-40). Friuli Venezia Giulia, Trentino Alto Adige, Sardinia and Calabria have medium-low number of units (16-20), while Val d’Aosta, Umbria, Molise and Basilicata have the lower number of units (2-15). Research Excellence Units are more widespread (Figure 3b). Latium, Campania, Sardinia, Umbria and Basilicata show a class of distribution of Research Excellence Units higher than for Local Units of companies that could be due to scarce technology transfer at local level.

Conclusions • Among energy technologies, RES and Energy Storage Systems have a high potential of development in Italy. • Research has facilitated the market penetration of some specific technologies. • A steady dialogue between research institutions and industry is necessary to achieve decarbonisation targets and economic growth. • Greater support to research on technology transfer will enhance local industrial development. • The proposed methodology has replicability characteristics in other territorial contexts. References [1] E.ON. Carbon, Cost and Consequences 2008. E.ON UK publication [2] Boston A. Delivering a secure electricity supply on a low carbon pathway 2013. Energy Policy; 52: 55-59. [3] Noh H, Seob J, Yoob H. S, Leea S. How to improve a technology evaluation model: A data-driven approach 2018. Technovation; 72–73: 1– 12. [4] Saaty T. S. Decision making with the analytic hierarchy process 2008. Int. J. Services Sciences; 1: 83-98. [5]http://www.dsctm.cnr.it/images/Eventi_img/de_carbonizzazione_3_ottobre_2017/RSE%20Decarbonizzazione_WEB.PDF [6]http://www.enea.it/it/seguici/pubblicazioni/pdf-volumi/v2017_catalogo-tecnologie-energetiche.pdf [7] https://www.r-project.org/ [8] Galili T. dendextend: an R package for visualizing, adjusting and comparing trees of hierarchical clustering 2015. Bioinformatics; 31, 22: 3718–3720. [9] https://www.qgis.org/it/site/




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New empirical production models for poplar plantations on farmland - a toolbox for improved management and planning operations

Birger Hjelm1,*, Tord Johansson2 1Swedish University of Agricultural Sciences, Department of Crop Production Ecology; 2Swedish University of Agricultural Sciences, Department of Energy and Technology; *corresponding author email: [email protected] Abstract This work presents a new empirical production model for poplar plantations on farmland. It describes a toolbox for improved management and planning operations. Keywords bioenergy; farmland, poplar Introduction The interest in the cultivation of fast-growing tree species and hybrids of deciduous trees on abandoned cropland increases. Interest in utilizing trees for bioenergy production has increased drastically in recent decades. Poplars (Populus spp.) are an exotic group of species in Sweden. Hybrid poplar plantations with short rotation (≤ 20 years) established on farmland in south and central Sweden, have shown promising production figures and been in focus as a future potential bio-fuel feedstock. A study [1] financed by the Swedish Energy Agency emphasized hybrid poplars plantations as a potential future bioenergy resource. A major effort began to establish tree plantations, including poplar, on farmland in the late 1980s. To date, the area of mature poplar plantations in Sweden is less than 1 000 ha [2]. This area can be expected to grow due to increased demand of bioenergy derived from national and international climatic goals of reduction of fossil energy dependency. Several studies have considered ecological and environmental aspects of poplar plantations in Sweden and not at least in the world [3, 4] of which two are exemplified here. The advantages of growing poplars in short rotation forestry have been discussed from a production perspective in Sweden [5-7]. In an overview, Rytter [8] reported biomass amounts of 3.2-13.6 tons ha-

1 year-1 for different poplar clones and species. In a study on commercial plantations from late

1980s hybrid poplar produced an average volume close to 19 m3 ha-1 year-1 compared to plantations of hybrid aspen with a production of 13 m3 ha-1 year-1 [9]. It is essential for landowners, forest- and energy companies and other actors who are interested in establishing poplar plantations with short rotations that there are tools available to calculate and predict the outcome in volume and biomass. In recent years, we have developed models for estimating yield and volume of individual poplar trees [10-12] which in addition also present production studies of poplars root and stump biomass [13] and second generation poplar sprouts [14]. We have finally also studied the properties of false heartwood of poplar stems growing at 22 sites in Sweden [15]. Equations for predictions of the stem volume and commercial volume for specified minimum diameters are the most used in Scandinavian forest management. Most of them depend on two independent variables, the total height (H) and diameter at breast height (DBH). Some equations are functions of DBH alone [16, 17]. Other researchers have proposed equations that use a broader range of independent variables, such as the diameter at a specified upper height [18, 19] the height at the crown base, the bark thickness, and site indicator variables such as altitude, soil type, and vegetation type, etc. The models usage is non-destructive and can be applied on standing trees in growing plantations.




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Models and Research Outcomes 1) Volume models for individual Poplar trees: One equation with dbh (D) and total height (H) as independent variables were constructed for stem volume estimation (V) and compared with a number of published equations (Tab 1). Table 1. The three best ranked stem volume equations

2) Taper model for individual Poplar trees: Taper models estimate diameter (d) using DBH, corresponding height (h) and total height (H) as independent variables, some advance and complex models also includes inflexion points (ip) where one form section of the tree (neiloid, paraboloid and cone) shifts into another (Fig 2). Taper models are useful for various purpose, among others estimating properties of different assortments with mini diameter restrictions. The objective was to develop a simple taper equation with good ability to predict diameter at a given height and compare it with common published taper equations (Tab 2).

Figure 2. Variables in taper equations.

Table 2. The six best ranked taper equations

3) Biomass models for Poplar stumps and 2nd generation coppices: There are two ways to manage the remaining stumps after harvest: 1) Excavation (Fig 3 a-b), or 2) Management of sprouts established on stumps (Fig 3 c-d). Models for estimation of individual stumps and coppice biomass were developed. Biomass production of 1000 excavated stumps could be 45-50 t d.w. ha-1. The stump was 74% on average of the total stump-root biomass. Roots (>50 mm) made up the remaining 24%. Biomass of 7-year-old coppices on 1000 stumps could be 30-35 t d.w. ha-1.

Figure 3 a. Excavated Poplar stump

Figure 3 b. Stump biomass by (dry kg) by dbh (total & roots)

Figure 3 c. Stump with established sprouts four months after harvest.

050

100150200250300

0 100 200 300 400 500 600 700

dbh (mm)

Stu

mp

we

igh

tkg

d. w

.

Tot Stump (• )roots(x )

Equation

Expression Absolut

Bias

(dm3)

Abs

Bias

%

1) (Hjelm &

Johansson

2011)

V = b1 (2+(D/H)) + b2H 2 + b3DH2 25.13 3.8

2) Fowler & Hussain

(1987)

V= b1 +b2D b3Hb4 25.07 3.8

3) Opdahl

(1992)

V= b1 + b2D - b3D 2 + b4D

2H 26.86 4.1




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Figure 3 d. Sprout biomass (dry kg) by dbh (by the fractions) 4) Models for prediction of false heartwood properties in Poplar stems: All of the sampled stems contained false heartwood. At 0 – 50 % of stem height, all sampled trees were discolored and at 90 % of stem height, 33 % were discolored. The percentage of false heartwood area by stem area was highest at 1 % and 10 % of stem height (26.6 % and 24.7 % respectively). Equations were constructed describing the correlation between diameter at breast height and the diameter of false heartwood at different stem heights (Fig 4 a-c) aimed for stems to be used for construction. However, most of the fast-growing poplars in Sweden is expected to be harvested as biofuel.

Figure 4 a. Properties of stem- and false heartwood volume by DBH

Figure 4 b. Properties of false heartwood diameter at different stem heights by DBH

Figure 4 c. Tree discs with false heartwood from six different stem heights

References 1. Rytter, L. Johansson, T. Karačić, A. Weih, M. 2011. Orienterande studie om ett svenskt forsknings-program för poppel. Summary: Investigation for a Swedish research program on the genus Populus. Skogforsk. Arbetsrapport nr 733, 165 pp. (In Swedish). 2. Nordh, N.E. Norberg, I. Paulrud, S. 2014. JTI-INFORMERAR JTI:s skriftserie 2014:1. Inför plantering av energiskog Lokalisering, samrådoch investeringsstöd. In Swedish. 16pp. 3. Christersson, L and Verwijst, T. 2006. Poppel. Sammanfattningar från ett seminarium vid Institutionen för Lövträdsodling, SLU, Uppsala 15 mars, 2005. In: Proceedings from a Poplar seminar at the Department of Short Rotation Forestry, SLU, Uppsala, Sweden. 4. Isebrands, J. G and Richardson, J. (Eds.). 2014. Poplars and Willows: Trees for Society and the Environment. CAB International and FAO, Rome. 634pp. 5. Christersson, L. 2010. Wood production potential in poplar plantations in Sweden. Biomass & Bioenergy, 34(9): 1289−1299. 6. Eriksson, H. 1984. Yield of aspen and poplars in Sweden. Ecology and management of forest biomass production systems. Department of Ecology and Environment, Swedish University of Agricultural Science. Report, 15, 393_419. 7. Persson, PO. Rytter, L. Johansson, T. Hjelm, B. Handbok för odlare av poppel och

05

10152025303540

0 30 60 90 120 150 180

Spro

utw

eigh

tkg

d. w

.

Diameter 10 cm above ground(mm)

Total (•), Stem (o)

Leaves (x), Branches (-)




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hybridasp. Manual for poplar and hybrid aspen management. Swedish Board of Agriculture, 2015, In Swedish. 8. Rytter, L. 2004. Production potentials of aspen, birch and alder a review on possibilities and consequences of harvest of biomass and merchantable timber. Skogforsk Redogo¨ relse nr 4, 64 pp. (In Swedish with English summary). 9. Johansson, T. 2010. Survival and growth of 20 -50 year old forest tree plantations growing on abandoned farmland. Department of Energy and Technology. Uppsala: Swedish University of Agricultural Sciences (SLU). Report 27, pp. 126 (In Swedish with English summary). 10. Hjelm, B. 2013. Stem taper equations for poplars growing on farmland in Sweden. Journal of Forestry Research 24(1): 15−22 11. Hjelm, B and Johansson, T. 2012. Volume equations for poplars growing on farmland in Sweden, Scandinavian Journal of Forest Research, 27:6, 561-566 12. Hjelm, B. Empirical Models for Estimating Volume and Biomass of Poplars on Farmland in Sweden. Doctoral diss. Dept of Crop Production ecology, SLU, Uppsala, Sweden. Acta Universitatis Agriculturae Sueciae, No. 2015:1. 13. Johansson, T and Hjelm, B. 2012. Stump and Root Biomass of Poplar Stands. Forests, 3, 166-178.

14. Johansson, T and Hjelm, B. 2012. The Sprouting Capacity of 8–21-Year-Old Poplars and Some Practical Implications. Forests, 3, 528-545. 15. Johansson, T and Hjelm, B. 2013. Frequency of False Heartwood of Stems of Poplar Growing on Farmland in Sweden. Forests, 4, 28-42. 16. Case, B and Hall, R. 2008. Assessing prediction errors of generalized tree biomass and volume equations for the boreal forest region of west-central Canada. Canadian Journal of Forest Research, 38(4), 878_889. 17. Gautam, S and Thapa, H. 2009. Volume equation for Populus deltoides plantation in western Terai of Nepal. Banko Janakari, 17(2), 70_73. 18. Brandel, G. 1990. Volume functions for individual trees, Scots pine (Pinus sylvestris), Norway spruce (Picea abies) and birch (Betula pendula and Betula pubescens). Department of Forest Yield Research. Report, 26, Garpenberg: Swedish University of Agricultural Sciences. 19. Burk, T. E. Hans, R. P. Wharton, E. H. 1989. Individual tree volume equations for the Northeastern United States: Evaluation and new form quotient board foot equations. Northern Journal of Applied Forestry, 6(1), 27_31.




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Infrastructure assessment through solar energy harvesting K. Wayne Lee1,*, Austin DeCotis1, David Schumacher1, Sze Yang2 1University of Rhode Island, Department of Civil Engineering, West Kingston, RI 02892 USA; 2University of Rhode Island, Department of Chemistry, Kingston, RI 02881, USA *corresponding author email: [email protected] Abstract The University of Rhode Island (URI) Transportation Research Center (TRC) is working to create a solar energy harvesting system for asphalt pavement. The objective behind this is to effectively cool the pavement on hot days, which will therefore increase the service life of the pavement. This will lead to fewer repairs that will save time, money and energy. The second and more important idea of this study will be harvesting as much solar energy as possible to create a more sustainable pavement. This energy could be used for a wide variety of uses including powering streetlights, ice melting, traffic signals and structural health monitoring system. The solar energy harvesting methods include embedding conductive piping and a temperature differential to generate power. Keywords Solar energy; asphalt pavement; energy harvesting; photovoltaic; Seebeck effect Introduction As the population continues to expand, natural resources become less available and the growing need for renewable energy intensifies. Renewable energies are clean and inexhaustible. Fossil fuels are currently the largest energy source utilized but the impacts caused by them are real and devastating. The greenhouse gasses created by the burning of fossil fuels continues to escalate the impacts of global warming. If the current trends of warming continue there will be catastrophic effects on the planet (Akbari 2005). Renewable energy sources which are very diverse and don’t produce greenhouse gasses are needed for the future.

Of this diverse group of renewable energy, one of the most important is solar energy. Every day the sun shines heating up the earth and the potential for this solar energy harvesting is unlimited. It is a clean and safe energy source that can replace fossil fuels. Solar energy is harvested through solar panels, which can be placed in almost any location if it receives sunshine. The more surface area a solar collector has, the more energy it collects.

Many homeowners are starting to install solar panels on their roofs to power their own homes in the US and around world. Panels are also installed in fields, on industrial buildings and even floating on water. The only negative to panels is that they take up a lot of space. To further increase the harvesting of solar energy more surface area for solar harvesting needs to be utilized. In the United States there are millions of miles of roadways and parking lots. The sun’s ultraviolet rays penetrate these roadways every day. These roadways provide such a large amount of surface area and would be ideal for solar harvesting if the unit can withstand the reoccurring loads of daily truck traffic. If all the surface area of the roadways in the U.S. were utilized for solar harvesting, fossil fuel consumption would plummet which would lead to a cleaner and healthier society.

On hot and sunny days, the roadways in the U.S reach up to 60oC (140OF). This high temperature is perfect for solar energy harvesting yet it is extremely detrimental to the roadway structure. The increased heat in pavement leads to the phenomenon called heat island effect. The pavement absorbs the sun's heat and traps the heat so urban and city




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areas with lots of paved roadways tend to stay warmer. This is turn leads to higher air conditioning costs in cities during the summer and a possible contribution to climate change. The high temperatures in the asphalt pavement also lead to rutting. This greatly decreases the life of pavement, which leads to expensive, and energy intensive repairs. The University of Rhode Island (URI) Transportation Research Center (TRC) is working to create a solar energy harvesting system for asphalt pavement. The idea behind this is to effectively cool the pavement on hot days, which will therefore increase the service life of the pavement. This will lead to fewer repairs, saving money and energy. The second and more essential idea of this study will be harvesting as much solar energy as possible to create a more sustainable pavement. This energy could be used for a wide variety of uses including powering streetlights, ice melting, traffic signals and structural health monitoring systems. Objective The objective is to develop a perpetual pavement system with an embedded solar harvesting unit for transportation infrastructures. Methods Embedded Conductive Piping URI TRC previously conducted a study on harvesting solar energy in asphalt pavement by embedding conductive piping in asphalt pavements in 2012. The objectives were to review literatures and existing practices to investigate novel methods to harvest solar energy from asphalt, generate different approaches to capture solar energy from asphalt, formulate conceptual design of systems to generate electricity and to determine the feasibility of the studied novel methods.

A prototype system was developed utilizing a 25 cm (10 in.) diameter by 60 cm (24 in.) tall clear schedule 40 PVC cylinder to simulate the pavement structure used in most roadways in Rhode Island (RI). This cylinder had 12.5 cm (5 in.) of subgrade soils, a 30 cm (12

in.) granular sub-base, 7.5 cm (3 in.) asphalt base, 5 cm (2 in.) asphalt binder course and a 5 cm (2 in.) asphalt surface course. This was the minimum thickness with RI Department of Transportation (DOT) standard specifications at the time. To accurately measure the temperature of the pavement structure 10 thermocouples were embedded in the pavement at varying depths. Cross-linked polyethylene (PEX) tubing was embedded 10 cm (4 in.) below the asphalt surface. This piping was chosen due to characteristics such as cost effective, flexible, melt resistant, and freeze cracking resistant.

Since this experiment was to be performed in a laboratory, the field conditions of the pavement had to be simulated. To replicate the heat of the sun a light bulb was used. Originally it was placed 15 cm (6 in.) above the pavement and ran for 8 hours to simulate a day of sunshine, the following 8 hours where the light was turned off were also recorded to determine how fast the pavement cools. After analyzing the temperatures, it was clear that the pavement was getting absurdly hot as it was reaching temperatures more than 104oC (220oF). To more closely simulate in-situ conditions the light bulb was placed 30 cm (1 foot) above the asphalt surface and control testing was ran. The results of this change were desirable as the pavement peaked at 60oC (140oF), which accurately portrays the surface temperatures of roadways in the summer. Three consecutive days of control testing were performed to ensure the results were accurate. For the next phase of testing the same experiment was performed however, after the light was on for 4 hours, the water was pumped through the pipes for a total of 8 hours. This was performed during the last four hours of the light being on and during the first 4 hours of the light being off. Three days of this testing was carried out to get an average result. The asphalt samples that had water run through the embedded pipes reached lower peak temperatures at every layer in the asphalt sample other than in the subgrade soils and cooled down faster compared to the testing that was performed without water. The temperature of the water increased 19oC (67oF) to 33oC (91oF) over the period of 8 hours while the system was run (Figure 1). This




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indicates that energy can be harvested from the pavement using embedded piping. However, recent testing done by the URI team observed that nearly 50% of this heat was inputted to the water from the pump. Although this was only a very small-scale experiment, only 20cm (8 in.) of piping were embedded in the pavement. Heat was also lost through the pipe as it travels from the asphalt sample to the holding tank. If this experiment was done on a larger scale with miles of roadway there is potential to harvest a massive amount of heat (Lee and Correia 2010). B. Seebeck Effect

The URI research team is performing experiments utilizing the Seebeck Effect. The Seebeck principle comprises of two dissimilar electrical conductors or semiconductors that have a difference in temperature to produce a voltage difference between the two substances. An experiment using the Seebeck principle was performed at Texas A&M University. The study was to develop a self-powered battery-less structural health monitoring system for transportation infrastructure. Recently an experiment using the Seebeck principle was performed to develop a self-powered battery-less structural health monitoring (SHM) system for transportation infrastructure (Karsilaya et al. 2018). The system would be capable of processing analog voltage input from a variety of sensors, such as strain gauges, traffic counters and piezoelectric weighing strips. An energy harvester driven by thermoelectric generators (TEGs) powered their system. TEGs function on the Seebeck/Peltier principle, allowing to translate the thermal differences between the upper and lower layers of asphalt concrete into electrical energy. The surface heat of the pavement will be transferred from the surface to the lower layers through insulated copper plates and the lower part of the harvester is kept cool through a heat sink. Thermoelectric generators can power SHM systems with enough temperature differential to power the TEGs. This SHM system developed by the Texas A&M University team appeared to be successful. The system accepts analog voltage input from a variety of sensors, is readily programmable, functions without a storage

battery, and can continuous retrieve wireless data. The URI research team has been conducting similar studies. Results Figure 1 shows the average monitored temperature at different depths in a pavement structure. This is during the common day while a pumping system is engaged, including water temperature.

Figure 1. Average Temperatures of Asphalt Layers.

Discussions The URI research team will continue to validate this system utilizing the Seebeck principle using thermoelectric generators and embedded conductive piping. Research will also be continued to create an efficient asphalt pavement solar collector. URI TRC is currently performing similar experiments with hopes to optimize this method for widespread use. Conclusions With more industries concentrating on greener technologies these different methods can help utilize and untapped source of energy that is ignored every day. RITRC Researchers of URI have been exploring solar energy harvesting from asphalt pavement, as we believe it has a strong potential to be utilized among all roadways and contribute to a more sustainable world. With the current need to switch to more sustainable energy it’s best to look at all possible alternatives. Although these ideas are still new yet with research and development, they can hopefully be optimized for widespread future use. Acknowledgments




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This research project was sponsored by USDOT Region 1 University Transportation Center (UTC) – Transportation Infrastructure Durability Center (TIDC). The authors would like to express sincere appreciation to TIDC and University of Rhode Island (URI). References Akbari, Hashem. (2005). Energy Saving Potentials and Air Quality Benefits of Urban Heat Island Mitigation (PDF) (19 pp, 251K). Lawrence Berkeley National Laboratory. Feng, J. and Ellis, T.W. (2003). ‘Feasibility study of conjugated polymer nanocomposites for thermoelectric”, Synthetic Metals, 135-136, pp 55-56 Karsilaya, A., Dessouky, S., and Papagiannakis, A. (2018). "Development of a Self-Powered Structural Health Monitoring System for Transportation Infrastructure" Publications. 27. Lee, K.W. and Correia, A. (2010). “A Pilot Study for Investigation of Novel methods to Harvest Solar Energy from Asphalt Pavements,” Final Report to Korea Institute of Civil Engineering and Building Technology (KICT). Lee, K.W., Craver, V., Kohm, S. and Chango, H. (2010). “Cool Pavements as a Sustainable Approach to Green Streets and Highways, Proc. of the 1st ASCE T&DI Green Streets and Highways Conference, Denver, CO. Lee, K. W. and Correia, A. (2011). “Investigation of Novel Methods to Harvest Solar Energy from Asphalt Pavements,” Proc. of the 7th International Conference on Road and Airfield

Pavement Technology (ICPT), Bangkok, Thailand, pp 1001-1008. Lee. K. W., Correia A. and Park, K. (2012a). “Solar Energy Harvesting from Asphalt Pavement to Reduce Dependence on Finite Fossil Fuel Supplies” Final Research Report to Expressway & Transportation Research Institute, Korea Expressway Corporation. Lee, K. W., Yang, S. and Correia, A. (2012b). “Investigation of Novel Methods to Harvest Solar Energy from Asphalt Pavements,” Proc. The ISAP International Symposium on Heavy Duty Asphalt Pavements and Bridge Deck Pavements, Nanjing, China. Lee, K.W. and Kohm, S. (2014). “Cool Pavements,” Chap. 16, Springer's Book on Climate Change, Energy, Sustainability and Pavements, Springer-Verlag, Inc., ISBN: 978-3-662-44719-2 _16. McCarthy, P., Li, W., and Yang, S.C. (2000). “New water-borne electroactive polymers for coating applications.” Polymeric Materials Science and Engineering, 83-315-316 Purohit, K., Yang, S. and Lee, K.W. (2013). “Polymer Thermoelectric Material for Energy Harvesting,” Proc. US-Korea Conference (UKC), East Rutherford, NJ. Racicot, R., Brown, R., and Yang, S.C. (1997). “Corrosion protection of aluminum allows by double-strand polyaniline” Syn. Met. 85, 1263. Visy, C., Fekete, D., Lian, J., Makra, P., Berkesi, O. and Patzko, A. (2007). Journal of Physical Chemistry. Yang, S.C., Brown, R., and Sinko, J. (2005). “Anticorrosive coatings based on novel conductive polymers”, European Coating Journal, 11, 48.




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Assessing social acceptance of wind energy through policy comparative analysis

Cecilia Nardi1,2,*, Marina Penna1, Laura Gaetana Giuffrida1, Elena De Luca1,* 1Italian National Agency for New Technology, Energy and Sustainable Development (ENEA), Rome, Italy; 2University of Roma Tre, Rome, Italy; *corresponding author email: [email protected], [email protected] Abstract The present study aims at assessing social acceptability of wind energy, through a policy comparative analysis that involved six different EU countries. A survey, focused on three main subjects (wind power plant siting, authorization procedures and support schemes) was submitted to experts and the information on the related public involvement arrangements were collected. The presence of three levels of public involvement - information, consultation, participation - was analysed. The results suggest that concrete paths to social acceptance of wind energy pass through designing appropriate institutional spaces for public engagement. Keywords Wind energy; social acceptance; decision-making; public involvement; participation. Introduction This study aims to assess, through a policy comparative analysis of six different countries, the presence and the quality of the public involvement within the regulations and legislative procedures related to wind energy and to give political insights to deal with its social acceptance. The study undertaken is part of the EU H2020 WinWind project, aiming at enhancing the socially inclusive and the environmentally sound market for wind energy. A description of the different concept dimensions was carried out to fix a common framework in which contextualize the analysis. To give a complete description of the context, the current status of public involvement and engagement in the legislative procedures for wind energy is detailed as well as the main issues related to the expression of public dissent. Through a comparative analysis the study investigated and confronted different policies and the related tools provided from the six countries by filling a dedicated survey. To conclude, policy implications were introduced aiming at suggesting two general considerations to strengthen one of the basic

components of social acceptance: trust in the relationship between government and citizens. Methods Definition and dimensions of social acceptance Social acceptance is an often used term in the practical policy literature, but clear definitions are rarely given. According to the majority of the literature (Wustenhagen et al., 2007) there are three dimensions of social acceptance: socio-political, market and community acceptance. Socio-political acceptance is the broadest and most general level, to which can be subjected both policy and technologies. This dimension of acceptance concerns key stakeholders and policy-makers. In the market dimension, which can be expressed as the availability of the market to adopt an innovation, the main actors are consumers and investors, that, in the case of renewable energy acceptance, are the main responsible for fostering the “switch” towards a more sustainable system (Bird et al., 2002). The third dimension is the community acceptance and it is the dimension on which the research is focused. It refers, indeed, to the specific




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acceptance of siting decisions and renewable energy projects by local stakeholders, namely residents and local authorities. Moreover, in this context, procedural and distributional justice are fundamental. The only concept on which this research focuses on is the procedural justice, which measures the fairness of the decision making processes and whether the processes are giving all stakeholders an opportunity to participate (Gross, 2007). Context and issues In many countries there are several indicators showing that public acceptance is high, even where the government is not strongly supporting renewable energy (Wustenhagen et al., 2007). At the same time, it is also quite common to see that expressions of dissent and disagreement swell where they are the only concrete way the public finds to give voice to its needs and opinions. It is especially true at local level where the place-identity implications come into play: the more spaces for public expression are neglected by decision making processes focused on simplifying and streamlining the authorisation procedures, the more the wind farm projects are perceived as a threat rather than an opportunity (Firestone et al., 2018). That is why the change geared towards social acceptance has to be pursued at community level and the expression of dissent should be investigated in the light of the presence and quality of spaces for public participation. Expert - based survey The comparative analysis was based on an expert-based survey, delivered to six countries: Germany, Italy, Latvia, Norway, Poland and Spain. The survey, through qualitative data collection, aims at investigating the legislative framework and the regulatory measures, according to 4 main stages (WinWind, 2019): wind power plant siting, authorization procedures, support schemes for wind energy and financial participation. Only the first three stages are here considered. Moreover, in the survey public involvement was assessed according to a multilevel analysis, based on the

following order: information, consultation and participation. The absence of tools is the lower level found: it requires the citizens active themselves to look for information and ways to express their own opinion. Information tools allow the citizens to hear and the consultation makes they to have a voice. However under these conditions they lack the power to insure that their views will be heeded and they cannot rely on the possibility to influence the decisions. Participation represents the highest degree of public involvement, since it can be considered as the possibility to be directly engaged in the decision making process .

Referring to the first stage of the survey the main question is about the existence of a national spatial plan for wind power plant siting and then, in case of existence, the section is dedicated to the public involvement assessment. The second stage, after a detailed description of the existing authorization procedures, focuses more on the different levels public involvement before and after the approval. The third stage, dedicated to the financial support schemes analysis, is not here addressed. Results From the comparison of the surveys outputs, as far as the first stage is concerned, it is possible to see as Germany, Norway and Poland have wind farm siting spatial plans as well as public involvement tools. Germany has a spatial plan at national level strongly supported by regional and local plans. Similarly, Norway does have regional and local spatial plans with binding nature, but the plan at the national level is still on the hearing stage. In Poland there are spatial plans at regional and local level. Norway and Poland have institutional designed tools for all levels of involvement, while Germany provides only for information and consultation tools. Italy, Latvia and Spain do not have any plan for wind power plant siting, either at national or at regional/local level. Secondly, the output analysis had been devoted to assess the different levels of public involvement within the authorization procedures. In this case, Germany lacks of participation tools while Italy and Spain miss all levels tools. Generally, public consultation is performed




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only within the Environmental Impact Assessments (EIA) procedures. There are different thresholds in terms of number and capacity of wind turbines, as well as other particular conditions, determining when EIA is mandatory. The arrangements for informing and consulting the public concerned are also determined by each country. Besides the analysis of the specific countries situations, the surveys outputs indicated positive results in terms of general consensus for participate initiatives. On the other hand, negative repercussions was observed in countries without siting spatial plan, mainly in three fields: ● relationship with the communities living in the areas affected by the power plants siting; ● national electricity transmission network development; ● cooperation among institutions responsible for different policies (i.e. industrial and energetic development, local development, environment, cultural heritage). Concerning the first aspect, the absence of a plan can prevent the establishment of a suitable environment for wide participation by stakeholders and by the citizens to a general renewable energy development. As far as the development of a national electricity transmission network is concerned, the lack of a plan prevented the efficient planning of the network development, generating inefficiencies within the systems and additional costs.

Referring to the third issue the absence of a plan hindered reaching a general agreement upon a reference framework, which would have facilitated agreements within the wind power plants authorization processes. A plan, indeed, would have acted as the right alternative, instead of constraining administrative procedures and timing. In particular in Italy, the wind power plant siting has been, for long time, matter of widespread disputes between the national government and the regions or municipalities.

It was also observed that the limited or even non-existing space for public involvement within the authorization procedures prevented the creation of any other form of public

participation except for the manifestation of dissent and disagreement. Discussions Summarising the results two main considerations particularly significant respect to the wind power plant acceptance emerged. The first one is related to the planning for wind power plant siting. Planning at the national, regional or at least at the local level seems to be a key factor in the management of wind - and more in general renewables - energy development because it can improve relationship with the communities living in the areas, which are affected by the power plants siting, and can drive the suitable developing of the electricity transmission network and strength the cooperation among public institutions responsible for different policy sectors.

The second consideration refers to the spaces for public involvement in the decision-making processes for wind farm siting and construction. Initiatives growing within the local communities meet large consensus. On the contrary, where public involvement is increasingly confined and limited in time and space, the probability to face resistance from local communities grows. If suitable public space for debate is denied, citizens will look for other way to express their own opinion and concerns, often motivated by mistrust and animosity. Such scenario is, indeed, dangerous because it negatively affects the whole relationships between the institutional arrangement and citizens and can trigger a vicious circle that further increases opposition. Lack of public participation can negatively influence other public policies for renewable energy developing. It is, for instance, the case of the extended timing of the authorization procedures. Institutional disputes, appeals to the decisions of the competent authority and other forms of dissent extend the length of decision-making processes and undermine the efforts to simplify the authorisation procedures. Conclusions




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This research is aiming at assessing social acceptance within the regulatory framework of wind energy of six different countries, by comparing their policies. After a short literature review of the concept of social acceptance and its dimensions and having detailed the current situation of public engagement or involvement, the methodology and the results are presented. Through a policy comparative analysis based on a survey filled by experts from the six countries, the two main results in terms of public involvement assessment are: ● Absence of a spatial plan for wind power plant siting negatively affects social acceptance, both in terms of practical issues, such as timing and heritage safeguard, and in terms of expression of public dissent ● Lack of institutionally defined spaces dedicated to public involvement within authorization procedures and support schemes are damaging not only the procedures themselves but also the relationship between citizens and institutions.

Thus, from the preliminary results it is possible to conclude that the path towards social acceptance necessarily passes through an effective and institutionally regulated public engagement, form which directly benefits both processes and relationship between citizens and institutions. Acknowledgments This article is an output of the research projects WinWind, funded within the Horizon 2020

Research and Innovation Programme of the European Union (Grant Agreement No 764717). References Bird L., Wustenhagen R., Aabakken J., A review on international green power market: recent experience, trends and market drivers. Renewable and Sustainable Energy reviews, 2002; 6:513-536 Firestone J., Hoen B., Rand J., Elliott D., Hübner G., Pohl J., (2018) Reconsidering barriers to wind power projects: community engagement, developer transparency and place, Journal of Environmental Policy & Planning, 20:3, 370-386, DOI: 10.1080/1523908X.2017.1418656 Groos C., Community perspectives of wind energy in Australia. The application of a justice and community fairness framework to increase social acceptance, Energy Policy; 2007, 35 Winwind, Deliverable 6.1. Screening of technical and non-technical regulations, guidelines and recommendations, 2019; EU H2020 Wolskin M., Planning for renewable schemes. Deliberative and fair decision making on landscape issues instead of reproachful accusations of non-cooperation, Energy Policy, 2007; 35 Wustenhagen R., Wolsink M., Burer M.J., Social acceptance of renewable energy innovation. An introduction to the context. Energy Policy, 2007; 35:2683-2691




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Energetic, exergetic, environmental and economic comparison between series and parallel schemes of hybrid solar gas turbines

Sofía Rodríguez Pita1, Javier Rodríguez Martin1,*, Celina González Fernández1, Susana Sánchez-Orgaz1, Ignacio López Paniagua1 1Department of Energy Engineering, ETSI Industriales, Universidad Politécnica de Madrid, Madrid, Spain; *corresponding author e-mail: [email protected] Abstract In this study, a comparison of two different configurations of solar-fossil hybrid plants is made. The difference between them is in the solar tower position, and the aim is to determine which of them performs better. The first configuration studied has the solar tower placed in series with the combustion chamber, and is based on the existing Solugas plant. The second configuration has the solar tower in parallel with the combustion chamber, this has not yet been implemented, and could be an attractive alternative for future hybrid plants. A 4E analysis was made, resulting in a better energetic, exergetic and economic performance of the series configuration. The environmental analysis showed an advantage of the parallel configuration. However, should the plant be constrained to work predominantly without the solar tower, the series configuration would have a better environmental performance. It can be concluded that the optimal configuration depends on site conditions. Keywords Solarized gas turbine; solar tower; energy analysis; exergy analysis; environmental analysis; Levelized Cost of Electricity Introduction Hybridization of fossil plants with Concentrating Solar Power (CSP) technologies is becoming increasingly important, as these hybrid plants offer the possibility of a lower fuel consumption and CO2 emissions.

The combination of both technologies means that the advantages of the two can be had. The solar part provides renewable energy, and the fossil part ensures energy generation. The influence of the solar part position inside the plant is evaluated in this study. Subject of the study Among the different CSP technologies, in this study a solar tower is used, and to assess the influence of its placement, two configurations are studied.

The first is the existing Solugas plant in Sevilla (Spain), a modified gas turbine that incorporates a solar tower to preheat the air

entering the combustion chamber; this scheme will be referred to as series configuration. In the second scheme, the solar tower is placed in parallel with the combustion chamber, so the air passes through either one of them; this will be denoted as parallel configuration. This parallel configuration could be an interesting alternative for future hybrid plants. Methods In order to compare both schemes, a 4E (energetic, exergetic, economic and environmental) analysis is carried out. Thermoflex and Engineering Equation Solver models are developed to provide detailed calculations, considering that the solar tower is working or out of service, thus setting four different scenarios.

Additionally, an annual simulation is carried out with a working solar tower. The equinoxes and solstices are used as representative days of the year to take into




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account the variation of solar irradiance, and obtain more accurate results. Throughout the calculations, clear skies are always considered. The design point used is the summer solstice, 22nd June, at noon, and the ambient conditions are set according to ISO 2533 (1.013 bar and 15º). A solar multiple of 1.2 is used. Efficiencies and temperatures are taken from data available about Solugas. According to Korzynietz et al., the plant has an output of 4600 kW, a Turbine Inlet Temperature of 1150º and a solar tower outlet temperature of 800º. The efficiencies of both compressor and turbine are adjusted using the outlet temperatures provided by Korzynietz et al. The parallel configuration retained most of Solugas parameters, but needed a slight adjustment of the combustion chamber and solar tower outlet temperatures in order to provide 1150º as TIT when working in the Design Point conditions. These temperatures are set as 1000º for the solar tower and 1425º for the combustion chamber. Other parameters such as the latitude and type of receiver (cavity), are maintained for both. Energetic Analysis The efficiency calculated, η, takes into account the solar energy provided. The equation used is η= W/(m_fuel ∙LHV+ Q_solar ) Where Qsolar is the energy provided by the heliostat field, calculated as Qsolar = DNI • total reflective surface Exergetic Analysis The exergetic efficiency is calculated with the formula ξ= W/(E_fuel+E_solar ) Where the exergy introduced by the solar field (Esolar) is calculated using the equation formulated by Petela, E_solar=Q_solar [1+ 1/3 (T_0/T_i )^4- 4/3 (T_0/T_i )] with T0 being the ambient temperature and Ti that of the solar surface (5800 K). To calculate the exergetic destruction, the formula I=m T_0 (s_out- s_in) is used Economic Analysis

The Levelized Cost Of Electricity (LCOE) is calculated for the two configurations using the formula LCOE= (C_i ∙CRF+C_(O&M)+C_F)/Eg Ci (initial investment costs), and CO&M (annual operation and maintenance cost), are calculated with data provided by Pitz-Paal et al. The heliostat price in Ci is of 150 €/m2, this parameter is modified in a sensitivity analysis carried out. The Capital Recovery Factor (CRF) is obtained with an interest rate of 4%, and the lifespan of the plant is taken as 25 years (Rovira et al., 2016). CF (annual fuel cost) is calculated knowing the annual fuel consumption and the Lower Heating Value. The fuel price considered is 23.2 €/MWh (Rovira et al., 2016), with this value a sensitivity analysis is also carried out. Eg, annual electricity generation, is obtained knowing the plant provides 4600 kW, and supposing it operates non-stop during the year. Environmental Analysis The annual simulations carried out are used to obtain much more precise results regarding fuel consumption and CO2 emissions. Results Outside of the 4E analysis, the resulting solar tower and heliostat field have the following characteristics, in the series configuration, the solar tower calculated had a height of 79 m, and 93 heliostats. In the parallel scheme, a 88 m tower and 193 heliostat field were obtained. Energetic Analysis The efficiency of both configurations diminishes when the solar tower is used, as shown in Table 1. Table 1 Results of the energetic analysis

Efficiency Series Config. Parallel Conf.

With solar tower

23% 21%

Without solar tower

29% 28%

Exergetic Analysis




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The exergetic destruction obtained is significantly higher when using the solar tower, it increases from 6.4 MW to 9.5 MW when the solar tower is used in the series scheme, and from 5.8 MW to 11.3 MW in the parallel scheme. The exergetic efficiencies can be seen in Table 2. Table 2 Results of the exergetic analysis

Efficiency Series Config. Parallel Conf.

With solar tower

23% 22%

Without solar tower

28% 27%

Economic Analysis The LCOE of the plants operating with the solar tower is lower than that of the fossil ones, as can be seen in Table 3. Table 3 Results of the economic analysis

LCOE (€/MWh) Series Config. Parallel Conf.

With solar tower

86.87 86.94

Without solar tower

88.09 91.30

The sensitivity analysis carried out shows an improvement of the parallel configuration’s LCOE when the heliostat price diminishes. As regards the fuel price, a reduction would favour plants without solar tower. Environmental Analysis The results of the environmental analysis are shown in Table 4. Table 4 Results of the environmental analysis

Fuel Consumption (ton/year)

Series Config. Parallel Conf.

With solar tower

8802 8495

Without solar tower

9932 10332

CO2 emissions (ton/year)

Series Config. Parallel Conf.

With solar tower

24368 23485

Without solar tower

27467 28503

Discussions The tower height and number of heliostats in the series configuration are slightly higher than the Solugas plant data, but when constraining the power given by the tower to Solugas values, the resulting tower fitted Solugas parameters. Seeing that the power provided by the taller solar tower was significantly bigger, 5 MW compared to 4 MW, the following calculations were made with the 79 m tower. Exergetic destruction is highest in the solar tower, alternatively, for the non-working solar tower (or fossil mode), exergetic destruction is highest in the combustion chamber. Because of this high irreversibility introduced by the solar tower, the efficiency of the solar modes is lower than that of their fossil counterparts. In the economic study, the sensitivity analysis carried out with the fuel price, showed a reduction of the LCOE of the fossil modes when fuel price was reduced. In the case of the series configuration, the LCOE of the fossil mode became lower than that of both solar modes when fuel price dropped below 20 €/MWh. Above a price of approximately 23 €/MWh, the LCOE of the solar modes was lower, but rather similar between the series and parallel schemes. The variation of the heliostat price revealed an improvement of the parallel configuration when the price is lower than 141.4 €/m2, this scheme has more heliostats and they are the biggest contribution to the initial investment costs. The environmental analysis showed an improvement when the solar tower is used. This was more predominant in the parallel configuration. Conclusions The hybrid solar gas turbines are an intermediate step between fossil technologies and standalone solar thermal plants. Two different arrangements are possible: serial and parallel. The series configuration presents a




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better, energetic, exergetic, and economic performance. From an environmental point of view, the parallel configuration offers lower fuel consumption and CO2 emissions. Seeing the results obtained, locations where the irradiation is high, and the sky is usually clear, could benefit from the reduction in fuel consumption and emissions observed for the parallel scheme. Locations with low irradiation and/or intermittent solar resource would be forced to rely more on the fossil part, making the series scheme preferable from all 4 points of view. Acknowledgments This research was supported by a collaboration grant 2018-2019 (Sofía Rodríguez Pita) of Spanish Ministry of Education, Culture, and Sports

References Korzynietz R, et al. Solugas–Comprehensive analysis of the solar hybrid Brayton plant. Solar Energy 135 (2016): 578-589. Petela R. Exergy of Heat Radiation. Journal of Heat Transfer 1964; 86:187. Pitz-Paal R, Dersch J. and Milow B. European Concentrated Solar Thermal Road Mapping. ECOSTAR, SES6 - CT - 2003 - 502578, 2005. Rovira A. et al. Analysis and comparison of Integrated Solar Combined Cycles using parabolic troughs and linear Fresnel reflectors as concentrating systems. Applied Energy 162 (2016): 990-1000. Thermoflex(2019) Software: THERMOFLOW.INC. Available at: https:// www.thermoflow.com




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Time-dependent model of solar thermoelectric generators for enhancing conversion efficiency

An-Chi Wei1,*, Mu-Wen Lin1, Jyh-Rou Sze2 1Graduate Institute of Energy Engineering, National Central University, Taoyuan, Taiwan, R.O.C.; 2Instrument Technology Research Center, NNational Applied Research Laboratories, Hsinchu, Taiwan, R.O.C.; *corresponding author email: [email protected] Abstract In this study, the model of solar thermoelectric generators (STEGs) has been constructed to investigate the performance of STEGs via the finite-element method. For enhancing the conversion efficiency of STEGs, the effects of solar-selective coating and parallel-stacking arrangement have been modelled. The simulation results show that the higher the absorption and the lower the emittance of solar selective coating, the higher the voltage generated by STEGs. Meanwhile, the simulated conversion efficiency of 11 stacked STEGs with the designed solar-selective coating reached 8.4%, which was 4.9 times of that of the single STEG. Keywords Solar thermoelectric generator; modelling of thermoelectric generator; Solar-selective coating; thermally parallel stacking Introduction Due to overuse of fossil fuel and excessive emission of greenhouse gases, global warming and extreme weather have become significant global issues, prompting the development of green-energy technique, such as solar-energy technology. Being an energy source, solar power can be used to generate electricity through photovoltaic panels, thermoelectric materials, and so on, or thermal energy through solar collectors (G. Boyle, 2012; M. Ortega et al., 2013; P. Sundarraj, et al., 2014). Among solar-thermal techniques, the thermoelectric (TE) approach has drawn attentions owing to its ability of conversing solar heat and waste heat into electricity. However, the conversion efficiency of such a solar TE generator (STEG) is not high enough. To enhancing the conversion efficiency, one fundamental approach is improving the quality of TE materials. Generally, the material performance is depicted by its figure of merit, ZT:

ZT = S2σT / k, (1) where S, σ, T and k are the Seebeck coefficient, the electrical conductivity, the temperature of the TE material, and the thermal conductivity,

respectively. Generally, the TE material is chosen according to the operating temperature of the system. On the other hand, utilization of a concentrator can enhance the solar irradiance onto the STEG and then increase its temperature, leading to higher conversion efficiency. Further, with the assistance of the selective coatings and the thermally parallel stacking, the conversion efficiency has been reported to be enhanced more (N. Selvakumar and H.C. Barshilia, 2012). Since the conversion efficiency of STEG is affected by various parameters, it is worthy to analyze and optimize the parameters of a STEG in advance for its high conversion efficiency. In this study, a three-dimensional time dependent model of STEG is proposed for investigating the concentration, the selective coating, and the thermally parallel stacking of a STEG. The absorption and emittance of selective coatings were labelled as α and ε, respectively. These two parameters were analyzed first to explore their influences on the temperature difference and the power generation as well as the conversion efficiency of a STEG. The simulation results show that increasing the parameter of absorption brought about the better conversion efficiency.




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Then, the number of stacked modules was studied. It shows that the increment of stack modules contributes to the increased conversion efficiency, agreeing with the results in the literature. Meanwhile, the concentration effect was also investigated during the above-mentioned analyses. Principles Since a STEG is operated outdoors, solar irradiance is a key influencing factor. When the irradiance becomes larger, the radiant heat flux through the TE generator of STEG also increases. Then, the temperatures difference between the hot and the cold sides of the STEG is increased, and the power density caused by the thermal conduction, qd, can be derived from the heat balance:

qd = -k(TH-TC)/L , (2) where k and L are the thermal conductivity and the thickness of the TE generator, respectively. TH and TC are temperatures of the hot and the cold sides of the TE generator, respectively. In addition, the ambient temperature and the thermal convection cause the heat loss as well. If ambient temperature is low, and wind is strong, equivalent to a high convective coefficient, the operating temperature of the STEG system will be lowered, resulting in the lowered TE efficiency. The power density from such convention follows the formula:

qv = h (Ts-Ta), (3) where h is the convective coefficient, and Ts and Ta are the surface temperature and the ambient temperature, respectively. Meanwhile, the temperature difference between the surface and the ambiance results in the heat dissipation due to the radiation. The power density from the radiation follows the formula:

qr=ϵs(Ts4Ta

4) (4) Based on the mentioned equations, a model for thermal analyses was then constructed. Models A commercial TE generator was utilized for evaluating the proposed model. In such a TE generator, the materials of its hot and cold sides were ceramics, and the TE material was Bi2Te3. The constructed model in COMSOL

Multiphysics and the detailed geometric parameters of the TE generator are presented in Fig. 1 and Table 1, respectively. The thermal conductivity of alumina ceramic substrate was set as 29.2 W/ mK, and the hot side of the TE generator was treated with the solar selective coating. The simulation was based on the time-dependent flux density of solar radiation at the

convection coefficient and the ambient temperature were set as 10 W/(K•m2) and

were the absorption coefficient and the emittance of the solar selective coating. After calculating the heat losses due to the conduction, convection, and radiation, the proposed model obtained the temperature difference between the hot and the cold sides of TE generator, the output voltage and the output power in turn.

Figure 1 STEG includes TE module and heat sink. Table 1 Parameters of TE module

Geometric parameter Value

Top area of TE module 4040 mm3

Thickness of substrate 0.8 mm

For investigating the effects of the solar selective-coating materials, the proposed model explores such materials by their absorptance and emittance. According to the records in the literatures, these parameters of the solar selective materials in simulation are listed in Table 2. Table 2 Parameters of TE module




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Material ɑ (absorptance) 𝝐(emittance)

Al-Ge-SiO 0.79 0.01

Ni-Ge-SiO 0.85 0.03

Cr-Cr2O3 0.89 0.05

Co-Al2O3 0.95 0.07

Results According to the modelling results, when the temperature difference between the hot and

voltage increases 0.15 V. Meanwhile, the experimental results show that when the temperature difference between the hot and

discrepancy between the simulated and experimental results is within 0.08 V. Because of the low discrepancy, the model is considered as acceptable.

Figure 2 Simulated and measured output voltage for varied temperature difference between the hot and the cold sides.

Based on such an acceptable model, the characteristics of solar-selective coating was investigated. The variables were the different coating materials with the different absorptance and emittance. The results show that the material with the higher acceptance contributes more temperature difference between the hot and the cold sides, as illustrated in Figure 3.

Figure 3. Simulated temperature difference between the hot and the cold sides.

Figure 3 shows that the materials with different acceptance and emittance contribute more Conclusions A short summary of this paper is listed as follows: A time-dependent 3D model for a solar TE generator (STEG) gas has been developed to analyze the thermal-electric performance. The simulated results agreed with the experimental ones. From the modelling results, the selective-coating material with the higher absorptance brings about the higher conversion efficiency. Acknowledgments The authors appreciate financially supported by the Ministry of Science and Technology, Taiwan, R.O.C. under the contracts: MOST 107-2221-E-008-093 and 107-2221-E-492-026-MY3, and Academia Sinica, Taiwan, R.O.C. under the contract: AS-SS-108-04-02. References G. Boyle, Renewable Energy: Power for a Sustainable Future, 3rd edition 2012; Oxford University Press, Oxford. M. Ortega, P. del Río, E. A. Montero, Assessing the benefits and costs of renewable electricity, Renew. Sustain. Energy Rev. 2013; 27:294-304.




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N. Selvakumar and H.C. Barshilia, “Review of physical vapor deposited spectrally selective coatings for mid- and high-temperature solar thermal applications”, Sol. Energy Mater. Sol. Cells 2012;98:1-23.

P. Sundarraj, D. Maity, S. Sinha Roy, and Robert A. Taylor, Recent advances in thermoelectric materials and solar thermoelectric generators, RSC Adv. 2014;4:46860-46874.




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Modelling of automatic generation control for multi-area integrated power system equipment including renewable energy systems

M. Furkan Yılmaz1, Haluk Gözde2, M. Cengiz Taplamacıoğlu3,*, Mehmet Karakaya3 1Turkey Electricity Transmission Company, Ankara, Turkey; 2National Defence University, Electronics and Communication Eng. Dept., Ankara, Turkey; 3Gazi University, Engineering Faculty, Electrical and Electronics Eng. Dept., Ankara, Turkey; *corresponding author email: [email protected] Abstract Nowadays, increasing demand is mostly providing with different fossil sources, hydroelectric and even with the nuclear energy plants. Therefore, the importance of renewable energy sources increases day by day for cleaner environment and less emission for human being. As a result of this different energy sources, the new integration and cooperation problems emerge. In this study, a multi area model of Automatic Generation Control (AGC) system including both classic thermal power plants and also renewable power plants including solar and wind farms are established in MATLAB/Simulink simulation programme. These power plants in entire system are weighted according to their participation. After that, the effects to the frequency stability of the power system according to their participation to the either primary or secondary control loops are investigated as different cases. Controlling the secondary loop of AGC for different participation cases is provided by using proportional-plus-integral (PI) controller which is optimized with Particle Swarm Optimization (PSO) algorithm. At the end of the study, the dynamic response of the model presented and interpreted in detail. Keywords Automatic Generation Control; Renewable Energy Systems; Solar Farm; Wind Farm; Particle Swarm Optimization Introduction Different imbalances have occurred due to the growth of the power systems, the continued expansion of the connection network, the use of different control methods as a result of the development of technology, and the increasing operations. This has led to a review of system stability and stability classifications in power systems [1].

The balanced operation of the frequency depends on the continuity of generation and consumption. If the generation is more than consumption, the frequency of the system increases. When the consumption is higher than generation, the frequency of the system decreases, i.e. the frequency decreases if the generation cannot compensate the consumption. The adaptation of the speed regulator must be ensured by an appropriate and specific control strategy to ensure better frequency stability [4]. For this purpose PI (proportional-integral) controller has been

used. The controller must adjust the gain to correct errors in the frequency. However, due to the complexity of power systems, it is not appropriate to adjust the gain of the PI-controllers by conventional methods. New adaptive methods are used to adjust the gain of the PI-controller [5, 6]. The use of the Particle Swarm Optimization (PSO) algorithm, which is suitable for these methods, is one of the most common.

The aim of this study is to use models that added renewable energy sources with new combinations for automatic generation control which are different from the above literature and also to adjust the gain of PI-controllers for new models. For the models whose generation elements are different to the load frequency control, the most appropriate PI-controller gains are adjusted by PSO algorithm. Methods Modelling




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In this study, the multi-area interconnected electrical energy system model has been used. Hydraulic, thermal, natural gas, solar, wind and nuclear generation units are take into account in the models. Five different models are established. The participation generation units are given in the tables below. Table 1 Participation status of power plants in load-frequency control

Thermal Hydraulic N. Gas Wind Sun Nuclear

P S P S P S P S P S P S

Model-1 x x X x x x x x

Model-2 x x X x x x x x x x

Model-3 x x X x x x x x x

Model-4 x x X x x x x x x x

Model-5 x x X x x x x x x x x x

Figure 1 shows the Model-2, where all generators participate in the secondary frequency control.

Figure 1. Model-2 built interconnected

Five scenarios are applied for each model. In the models, the participation of the plants in frequency control is different. Table 2 Participation rates of power plants

Thermal Hydraulic N. Gas Wind Sun Nuclear

Model-1 20% 30% 30% 12% 8% 0%

Model-2 20% 30% 30% 12% 8% 0%

Model-3 20% 25% 25% 12% 8% 10%

Model-4 20% 25% 25% 12% 8% 10%

Model-5 20% 25% 25% 12% 8% 10%

In the models, the participation rates of the plants are different. In these models, the parameters of the PI controller controlling the secondary frequency are optimized by the PSO algorithm. Particle Swarm Algorithm PSO is an iterative method used for optimization in linear or non-linear systems similar to other genetic algorithms. PSO is inspired by the movement of birds and fishes. In general, it is an algorithm based on swarm behaviours [2]. The PSO optimization process is as follows: Lower and upper limits are determined for the values to be calculated. The initial position and velocities of the particle space set are evaluated. As a result of the particle calculation, the best values of the entire local swarm should be calculated. Each particle is compared to the previous conformity values and it is assigned to the local best value if it is better than the actual values up to that point. The local best suited values are compared to the conformity values of the global best position. If the location of the local best value is better, this value is transferred to the new global best position and conformity value of the particle. The position and speed of the particle are changed for a new operation. The process continues until the best conformity values are found or the iteration number ends. This loop has the best global position value [3]. Results The PSO is operated for each model and the optimal values are determined. PI-controller gain values of the fastest and most effective response to system failure in all models are given in Table 3 . Table 3 Gain values of PI-controller Plants Model-1 Model-2 Model-3 Model-4 Model-5

Thermal P -5,00 -5,00 -5,00 -5,00 -5,00

I -4,67 -5,00 -5,00 -5,00 -5,00

Hydraulic P -3,33 -1,10 -0,03 -5,00 -5,00

I -1,52 -0,86 -0,06 -0,27 0,29

N. Gas P -1,75 -5,00 -2,80 -0,27 -1,03

I 0,42 -4,89 -4,20 -0,28 -5,00

Wind P - -5,00 - - -5,00




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I - 0,87 - - -5,00

Sun P - -0,86 - - -0,46

I - -5,00 - - -0,01

Nuclear P - - - -3,98 -5,00

I - - - -0,27 -3,45

The Table 4 shows the optimal minimum undershoot, maximum overshoot and the settling time for each model. Table 4 System Response Values

Model-1 Model-2 Model-3 Model-4 Model-5

Minimum

Undershoot -2,331.10-3 -2,370.10-3 -2,734.10-3 -0,332.10-3 -2,338.10-3

Settling Time 10,31s 15,80s 8,16s 8,35s 13,24s

Maximum

Overshoot 1,563.10-3 0,492.10-3 0,302.10-3 1,065.10-3 0,953.10-3

Figure 2. Response Oscillations of All Models

The Figure 2 shows system response oscillations. As a result of the optimization, it is observed that Model-1 has the lowest minimum peak time in frequency deviation. It is observed that Model-3 has the highest minimum peak time. Model-1, Model-2, Model-4 and Model-5's minimum peak times are observed to be very close to each other. In Model-3, the maximum number of zones are interpreted as the decrease in the number of zones in the frequency domain despite the increase of Model-1 and ,Model-2. Conclusions In this study, it is examined the efficiency of the load frequency control system of the multi-area interconnected system. The reaction of the system is analysed under equal load exchange. The PI-controller, which controls the secondary frequency in the models, has been optimized with the Particle Swarm Optimization algorithm. For the optimization, the best parameters of the controllers are

used. The load frequency control efficiency of the models are compared with each other. Finally, the obtained results showed that Particle Swarm Optimization is a sufficient algorithm to obtain PI-controller parameters. As a result, renewable energy sources, which are increasingly present in the interconnected system, should contribute to load frequency control. In order to operate the system more safely, it should be ensured that conventional generators continue production in the system. Conventional generators and renewable energy sources should be operated in a mixed structure. References [1] Kundur, P., Paserba, J., Ajjarapu,V., Andersson, G., Bose,A., Canizares, C., Hatziargyriou, N., Hill, D., Stankovic, A., Taylor,C., Cutsem, T.V., Vittal, V. (2004). Definition and Classification of Power System Stability. IEEE Transactions VOL. 19, NO. 2 [2]Kennedy, J., Eberhart, R. (1995). Particle Swarm Optimization, Proceedings of IEEE International Conference on Neural Networks, 1942-1948, WA, USA. [3]Gözde, H., Taplamacıoğlu, M. C., Kocaarslan. İ., Şenol. M. A. (2010). Particle swarm optimization based PI-controller design to load-frequency control of a two area reheat thermal power system, Journal of Thermal Science and Technology, 30(1): 13-21. [4]Elgerd, O.I., Fosha, C.E. (1970). Optimum megawatt-frequency control of multi-area electric energy systems, IEEE Transactions on Power Apparatus and Systems, 89(4): 556-563. [5]Kumar, I.P., Kothari, D.P. (2005). Recent philosophies of automatic generation control strategies in power systems, IEEE Transactions on Power Systems, 20(1): 346- 357. [6]Gözde, H., Taplamacıoğlu, M.C.,Kocaarslan İ. (2009). A Swarm Optimization Based Load Frequency Control Application In A Two Area Thermal Power System, International Conference on Electrical and Electronics Engineering - ELECO 2009, Bursa, Turkey.




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Energetic and economic comparison of agricultural biogas plants feed with silage and food waste

Jacek Dach1,*, Wojciech Czekała1, Patrycja Pochwatka2, Isaias Emilio Paulino do Carmo1, Alina Kowalczyk-Juśko2, Jakub Pulka1 1Poznan University of Life Sciences, Institute of Biosystems Engineering, Poznan, Poland; 2University of Life Sciences in Lublin, Department of Environmental Engineering and Geodesy, Lublin, Poland; *corresponding author email: [email protected] Abstract Substrates used in agricultural biogas plants play a dominant role in their energetic and economic balance. In typical biogas plant of the 1st generation (NaWaRo or its clones) working mainly with silages, the costs of substrates usually reach 35-50% of the profit from electric energy sold. The aim of the work was to compare different scenarios for feeding the biogas plant of the new generation which is going to be run in Autumn 2019 at Przybroda experimental farm. The experiments and calculations have shown that substrates play essential role in the economic balance of biogas plants. Yearly profit of 500 kW plant working with biowaste (re-food) is 498 kEUR higher comparing to maize silage scenario (typical for European biogas plant). In order to increase profitability, new generation biogas plants must necessarily be equipped with the possibility of using a wide range of waste substrates. Keywords biogas production; substrate; biowaste; economic balance Introduction Substrates used in agricultural biogas plants play a dominant role in their energetic and economic balance (Dach et al., 2014; Wandera et al., 2018). In typical biogas plant of the 1st generation (NaWaRo or its clones) working mainly with silages, the costs of substrates usually reach 35-50% of the profit from electric energy sold (Lewicki et al., 2013; Monforti et al., 2013). This is quite independent of the financial support system in EU countries (Germany, Czechia, Italy, France, Austria, Poland, etc.). However, Poland is a specific country where the financial support system collapsed in 2012 because of extremally fast grow of co-incineration of biomass imported from the almost whole world. That is Polish biogas sector tries to find (after 2012) the feeding strategies far from expensive maize silage scenario. Many owners of biogas plants in Poland started to look for different biowaste used as a substrate in order to decrease the exploitation costs of installations (Czekała 2017; Czekała et al., 2018).

The paper presents the comparison of different scenarios for feeding the biogas plant of the new generation which is going to be run in Autumn 2019 at Przybroda experimental farm (fig. 1).

Figure 1. Biogas plant in Przybroda in the final state of construction

This installation (500 kW of electric

power) was planned initially as a typical biogas plant using agricultural substrates like maize silage and cow manure. However, new technological solutions installed in this biogas plant (i.e., biotechnological accelerator) has




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increase wildly the spectrum of substrates which can be used for feeding fermentation process. That is why new scenarios were taken into account in order to decrease the costs of feeding and even reach a situation where profits from biowaste acquisition will increase the total profit of the biogas plant. The aim of the work was to compare different scenarios for feeding the biogas plant of the new generation which is going to be run in Autumn 2019 at Przybroda experimental farm. Methods During the research, 2 different feeding scenarios for Przybroda biogas plant were analyzed: 1. Conventional feeding (maize silage + cow manure), in this scenario substrates create costs for biogas plant. 2. Biowaste-based feeding (re-food + cow manure), biowaste substrates generate profit. All substrates were tested for methane production efficiency in Ecotechnologies Laboratory – the biggest Polish biogas laboratory placed at Institute of Biosystems Engineering, Poznan University of Life Sciences. The methodology of methane production test was based on German norms DIN 38414/S8 and VDI 4630. The physical and chemical parameters like pH, dry matter, organic dry matter, conductivity were also tested (Wolna-Maruwka and Dach, 2009; Janczak et al., 2013; Waszkielis et al., 2013, Janczak et al., 2017). It has to be underline that Ecotechnologies Laboratory has received (as the first Polish biogas laboratory) the prestigious certificate of the research quality from KTBL. The costs of substrates which has to be paid by biogas plant were: 28 EUR/Mg for maize silage, 10 EUR/Mg for cow manure. However, for re-food situation is inverse: each 1 Mg of this material received by biogas plant is the profit od 23 EUR/Mg. Simply, in this case biowaste owners have to pay to biogas plant owners to treat their organic waste. Analyzed biogas plant has 500 kW of electric power and 600 kW of heat. In both described scenarios whole produced electric energy is sold to the grid in Feed in Tariff (FiT) system with the price 147 EUR/MWh. Additionally,

80% of heat from co-generation can be sold to local network (5 EUR/GJ). Described biogas plant works in Dynamic Biogas technology which is characterized by very high performance, usually reach 8500 MWh/MW installed. That is why we fix working time of cogeneration unit (CHP) on 8500 workhours per year. Results In order to reach the CHP unit (500 kW of electric power) working 8500 h/a, it is necessary to produce 1,085,742 m3 of methane (content inside produced biogas). The substrates used in all scenarios had following production: - Cow manure: 38 m3 CH4/Mg; - Maize silage: 124 m3 CH4/Mg; - Re-food: 78 m3 CH4/Mg. Based on these efficiencies, the amounts of substrates needed for production 1,058,742 m3 of CH4 are as follow: - 1st scenario: 7800 Mg of maize silage and 2409 Mg of cow manure; - 2nd scenario: 12400 Mg of re-food and 2409 Mg of cow manure. ` It has to be underlined that the same amount of cow manure (2409 Mg per year) in both scenarios is simply related with real production of manure by milking cows in Przybroda experimental farm. The energetic calculations for 1st scenarios of feeding biogas plant is present in table 1, for the 2nd scenario in table 2. Table 1 The energetic calculations for 1st and 2nd scenario.

Parameter Value Unit

Working time of CHP 8500 hours/a

Electric efficiency of CHP 40 %

Thermal efficiency of CHP 48 %

Electric energy production 4221 MWh

Heat production 18237 GJ

Electric power 0.497 MW

Thermal power 0.596 MW

Table 2 The economic calculations for 1st and 2st scenario of different biogas plant feeding.

Analyzed parameter 1st 2nd Unit




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Cost of substrates

Maize silage -187 0 kEUR/a

Cow manure -78 -78 kEUR/a

Re-food 0 285 kEUR/a

Total costs -265 207 kEUR/a

Energy production

Electric energy price 147 147 EUR/MWh

Heat price 5 5 EUR/GJ

Electric energy profit 618 618 kEUR/a

Profit from heat sold 73 73 kEUR/a

Total profit 691 691 kEUR/a

Profit from digestates

Mass of digestates 9392 13624 Mg/a

Digestate price 6 6 EUR/Mg

Profit from digestate: 56 82 kEUR/a

Total economic balance: 483 980 kEUR/a

Economic analysis presented in table 2 is showing strongly advantage of biowaste feeding scenarios (with dominating re-food usage) over traditional maize silage based feeding. This is related mainly with completely different economic situations: for agricultural products like maize silage (also cow manure) the owner of biogas plant has to pay, however for receiving organic waste he can gain some money. In analyzed situation, the graphic visualization of both scenarios explains better the main differences (Fig. 2).

Figure 2. Profits and costs in both analyzed scenarios

The economic analysis has shown that for Przybroda biogas plant, the scenario with re-food (out of date food from one of the biggest Polish market network) can generate the profit 498 kEUR bigger than initially planned maize silage as the main substrate. This calculations clearly show that biowaste-based scenario can be strongly more economic for biogas plant owners that the most common scenario (maize

silage as main substrate) which is predominant in Europe. Conclusions On the base of research made in this paper, several conclusions were made: • Substrates play essential role in the economic balance of biogas plants. • Yearly profit of 500 kW plant working with biowaste (re-food) is 498 kEUR higher comparing to maize silage scenario (typical for European biogas plant). • In order to increase profitability, new generation biogas plants must necessarily be equipped with the possibility of using a wide range of waste substrates. Acknowledgments This study was performed as part of the statutory research no. 506.105.06.00 in the discipline of Environmental Engineering, Mining and Energetics, entitled "Energetic use of waste as a method of improving the environment". References Czekała W. Concept of IN-OIL project based on bioconversion of by-products from food processing industry. Journal of Ecological Engineering 2017;18(5):180–185. Czekała W, Cieślik M, Janczak D, Czekała A, Wojcieszak D. Fruit and vegetable waste from markets as a substrate for biogas plant. 18th International Multidisciplinary Scientific Geoconference SGEM 2018. Conference Proceedings vol. 18 Energy and Clean Technologies 2018;4.3:473-478. Dach J, Czekała W, Boniecki P, Lewicki A, Piechota T. Specialised internet tool for biogas plant modelling and marked analyzing. Advanced Materials Research 2014;909:305-310. Janczak D, Malińska K, Czekała W, Cáceres R, Lewicki A, Dach J. Biochar to reduce ammonia emissions in gaseous and liquid phase during composting of poultry manure with wheat straw. Waste Management 2017;66:36-45. Janczak D, Marciniak M, Lewicki A, Czekała W, Witaszek K, Rodríguez Carmona PC, Cieślik M,




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Dach J. Bioreactor Internet System for Experimental Data Monitoring and Measurement. Procedia Technology 2013;8: 209-214. Lewicki A, Dach J, Janczak D, Czekała W. The Experimental Macro Photoreactor for Microalgae Production. Procedia Technology 2013;8,:622-627. Monforti F, Bódis K, Scarlat N, Dallemand JF. The possible contribution of agricultural crop residues to renewable energy targets in Europe: a spatially explicit study. Renewable Sustainable Energy Reviews 2013;19:666-677. Wandera SM, Qiao W, Algapani DE, Bi S, Dongmin Y, Qi X, Liu Y, Dach J, Dong R.

Searching for possibilities to improve the performance of full scale agricultural biogas plants. Renewable Energy 2018;116:720-727. Waszkielis KM, Wronowski R, Chlebus W, Białobrzewski I, Dach J, Pilarski K, Janczak D. The effect of temperature, composition and phase of the composting process on the thermal conductivity of the substrate. Ecological Engineering 2013;61:354-357. Wolna-Maruwka A, Dach J. Effect of type and proportion of different structure-creating additions on the inactivation rate of pathogenic bacteria in sewage sludge composting in a cybernetic bioreactor. Archives of Environmental Protection 2009; 35(3):87-100.




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Evaluation of the influence of three microbial strains in the composition of the biol obtained from the treatment of textile industry waste

Villavicencio-Muñoz N1, Barreda-Del-Carpio J1, Cárdenas-Herrera L2,*, Garate-Manrique R3, Moscoso- Apaza G3, Villanueva-Salas J1 1Universidad Catolica de Santa Maria, School of Pharmaceutical, Biochemical and Biotechnology Sciences, Arequipa, Peru; 2Universidad Nacional de Santa Agustin, School of Medicine, Arequipa, Peru; 3Instituto de Investigación y Desarrollo para el Sur, Arequipa, Peru; *corresponding author email: [email protected] Abstract The objective of this research is to evaluate the use of different microbial consortia in the composition of the biol obtained from the treatment of textile industry waste in an anaerobic reactor. Three native strains of alpaca and sheep fiber were isolated: Psedomonas aeruginosa, Alcaligenes sp. and Proteus vulgaris, as well as 8 native strains of cow rumen: Fusarium sp., (4) Fusarium oxysporum (different varieties), Aspergillus sp., Monascus sp. and Aspergillus flavus. As a result, the biol obtained from the bioreactors has more N-P-K (Nitrogen-Phosphorus-Potassium), which helps vegetative growth and development. The amount of Ca (Calcium) and Mg (Magnesium) is similar to organic fertilizers and can be used in hydroponic crops. Textile waste is highly keratinous and causes environmental pollution in Peru. This justifies the implementation of new technology for processing residual fiber, obtaining bioproducts and taking care of the environment. Keywords Biol; anaerobic reactor; microbial consortia Introduction Peru is the world's largest producer of alpaca fiber. As it is known, the textile industry has grown considerably in the country. Therefore, also the waste generated by this industry during the weaving process increased. These wastes (sheep and alpaca’s wool) are keratinous materials that are difficult to degrade. For this reason, they are considered negative to the activities of their generators and not as a possible source of income. Wastes are usually disposed of by throwing them in dumps (Sedesol, 2004) or sanitary landfills, generating an additional cost to companies in our country and pollution of soil, air and water. This project seeks to evaluate the composition of biol using microbial consortia from the treatment of solid waste and obtain biol with the best characteristics for use it as fertilizer. An exploratory research was carried out as it investigates a little studied topic from an innovative perspective. In addition, the

approach is quantitative, as it represents a set of sequential processes where a series of data are collected for hypothesis approval. This research was carried out in Arequipa, Peru through an agreement with the Peruvian state with INNOVATE Peru, Universidad Catolica de Santa Maria, Inca Tops (textile company) and IiDS (institute), from March 2016 to April 2018. Methods Isolation, characterization and identification of micro-organisms from fiber of alpaca, sheep and cow rumen The collection of solid waste samples of alpaca and sheep fiber from the textile company Inca Tops located in the sector of Zamacola - Arequipa was carried out. The samples were taken from five different points within the facilities of the plant. The samples were labeled with letters A, T, L, S, C and M referring to each of the sampling points. Blood agar culture medium was prepared for 20 mL plates. Each




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sample was sown by striae. The plates were placed into the jar for anaerobes incubation for 15 days at 37°C. Then, the growth of the bacteria was observed, and it was repeated until pure strains were obtained. Fungi were isolated from the cow rumen, which was obtained from Don Goyo slaughterhouse located in Zamacola-Arequipa. The samples were taken from the different parts of the rumen folds and were labeled with letters P, MA, MB, MC. Sabouraud dextrose agar culture medium supplemented with Chloramphenicol and Gentamicin was prepared for 20 mL plates, using the streaking technique in each sample. Finally, the plates were placed into the jar for anaerobes incubation for 15 days at 37°C. Then, the growth of the bacteria was observed, and it was repeated until pure strains were obtained. The strains were taken to a certified laboratory for molecular identification. Configuration and construction of a bioreactor for the biological treatment of textile waste Three bioreactors were set up for the experimental tests, considering an effective volume of 11 L and a capacity of 20 L in total. The reactors have a spraying and recirculating system of the effluent inside. This system works with a pump and sensors that facilitate the water levels so it can be recirculated. It also has a grid at the bottom to prevent the passage of large particles. The bioreactors were inoculated as follows: bioreactor 1 with a bacteria consortium, bioreactor 2 with a fungi consortium and bioreactor 3 with a microbial consortium (bacteria and fungi). These worked for 45 days. Evaluation of biol composition The biol was analyzed after 45 days considering Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca) and Magnesium (Mg) as the most important parameters since they help the vegetative growth and development of the plants. These results were compared with biol of different biomasses as the biol of Don Goyo slaughterhouse, which was taken as reference in the city of Arequipa. Results

Three native strains of alpaca and sheep fiber were isolated, which were identified molecularly: Psedomonas aeruginosa, Alcaligenes sp. and Proteus vulgaris; and 8 native strains of cow rumen, which were identified molecularly: Fusarium sp., (4) Fusarium oxysporum (distintas variedades), Aspergillus sp., Monascus sp. and Aspergillus flavus.

Table 1 is a comparative table. It shows 3 biol produced with organic waste and 3 biol produced from textile solid waste (alpaca fiber and sheep wool, among others such as soil), which are the biol of the bioreactors. The pH must range between 6.5 - 8.5 to be considered boil (Seldesol, 2004). Discussion Bacteria isolated from the residual fiber resulted in Gram+. In anaerobic bioreactors, large numbers of Gram+ bacteria were found, mentioned by (Kröber et al. 2009), which would indicate that T-1, A-0 and A-3 could increase the efficiency of the process. Rumen is a very favorable environment for the growth of some microorganisms and could be considered as a continuous culture medium of great value for the development of anaerobic microorganisms (Grajales, 2014). This would indicate that the isolated strains of the rumen are anaerobic and could be developed in an anaerobic reactor. Conclusions • Three native strains of alpaca and sheep fiber were isolated, which were molecularly identified as Psedomonas aeruginosa, Alcaligenes sp. and Proteus vulgaris. Eight native strains were isolated from cow rumen, which have anaerobic capacity. These were identified molecularly and the strains are Fusarium sp., (4) Fusarium oxysporum (different varieties), Aspergillus sp., Monascus sp. and Aspergillus flavus. • After different experiments and analysis of parameters, it was concluded that the biol obtained from bioreactors 1 and 2 had a good amount of N-P-K. This indicates that it could be used as a liquid fertilizer. The amount




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of Ca and Mg found in biol resembles the amount of organic fertilizers. Therefore, it can be used in hydroponic crops. Acknowledgments I thank my parents for their unconditional support. I thank all the professors who supported me; and Dr. Villanueva for his trust and support. Finally, I thank INNOVATE Peru for the opportunity to be part of the team. References Alvarez Fernando. Preparación y uso de biol. Lima: Soluciones Prácticas, 2010.

Garzón Grajales, N. Caracterización e identificación molecular de hongos de suelo aislados de los páramos de Guasca y Cruz Verde, Cundinamarca-Colombia (Bachelor's thesis, Facultad de Ciencias).2014 Kröber, M., Bekel, T., Diaz, N., Goesmann, A., Jaenicke, S., Krause, L., Schlüter, A. Phylogenetic characterization of a biogas plant microbial community integrating clone library 16S-rDNA sequences and metagenome sequence data obtained by 454-pyrosequencing. Journal of Biotechnology. 2009 June; 142 (1): 38– 49. Sedesol, Ine. Informe de la situación general en material de equilibrio ecológico y protección al ambiente. México; 2004. página 220.

Table 1 Comparison of parameters

Parameter Source 1 Manual of biol preparation

Source 2 Cow dung

Source 3 Don Goyo slaughterhouse’s biol

Source 4 Reactor 1 biol (bacteria)

Source 5 Reactor 2 biol (fungus)

Source 6 Reactor 3 biol (consortium)

pH 5.6 7 7.2 8.38 8.37 8.96

Ca 112.10mg/L 1132.0mg/L _ 144.55mg/L 129.69mg/L _

K 860.40mg/L 2892.4mg/L _ 150.484mg/L 124.776mg/L _

Mg 54.77mg/L 544.4mg/L 20.76 mg/L 36.105mg/L 26.461mg/L 19.369mg/L

N 0.092 % 46 % 4.095 % 0.17% 0.18% 5.307%

P 112.80mg/L 57% ˂0.1 mg/L 4.242% 4.786% 0.002%




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Kinetics of biomethane formation during multi-co-fermentation of organic waste from food industry

Sylwia Stegenta-Dąbrowska1, Paula Żak1, Hubert Prask1, Małgorzata Fugol1, Agnieszka Medyńska-Juraszek2, Bogusław Dulian3, Andrzej Białowiec1,4* 1Wrocław University of Environmental and Life Sciences, The Faculty of Life Sciences and Technology, Institute of Agricultural Engineering, Wrocław, Poland; 2Wrocław University of Environmental and Life Sciences, The Faculty of Life Sciences and Technology, Institute of Soil Science and Environmental Protection, Wrocław, Poland; 3Varitex spółka z ograniczoną odpowiedzialnością spółka komandytowa, Łódź, Poland, 4Iowa State University, Department of Agricultural and Biosystems Engineering, Ames, USA; *corresponding author email: [email protected] Abstract Biochar (BC) addition is a novel and promising method for biogas yield increase. Organic waste from the food industry (OWFI) including waste from the slaughterhouse (WS) is an abundant easily biodegradable organic matter with a large potential for biogas production. Up to now, research on pyrolytic BC application for methane fermentation showed a positive influence on the increase of both biogas and biomethane yields. Another source of BC, besides the pyrolysis, maybe BC produced under torrefaction conditions (low-temperature pyrolysis). As a feedstock for torrefaction, the digestate from biogas plant may be used. In this research, for the first time, we tested the feasibility of increasing biogas yield and rate from OWFI digestion by adding BC, which was produced from biogas plant digestate via torrefaction. The proposed proof-of-the concept refers to an approach of biogas plant waste transformation to BC and its recirculation gaining the higher biogas production, and waste recycling. OWFI was fermented in the presence of BC with BC/(OWFI+BC) weight ratio from 0 to 10 % d.m. Multi-co-fermentation of OWFI consisted of waste from the slaughterhouse (30 % w.m.), waste from vegetables and fruits processing (30 % w.m.), pulp from sugar production (20 % w.m.), waste from milk processing (10 % w.m.), and waste from potatoes processing (10 % w.m.) was investigated. The study was conducted during 21 days under mesophilic conditions in n = 3 trials. The content of dry mass 5 % in all variants was constant. First order kinetics parameters of biogas production were estimated. Conceptual mass and energy balances of the biogas plant for OWFI utilization with BC recirculation were done. Keywords food waste; biochar; biogas; fermentation; torrefaction

Introduction Organic waste from the food industry (OWFI) including waste from the slaughterhouse (WS) is an abundant easily biodegradable organic matter with a large potential for biogas production. Biochar (BC) addition is a novel and promising method for biogas yield increase. Up to now, research on pyrolytic BC application for methane fermentation showed a positive influence on the increase of both biogas and biomethane yields. Another source of BC, besides the pyrolysis, maybe BC produced under torrefaction conditions (low-

temperature pyrolysis) (Dudek et al. 2019). As a feedstock for torrefaction, the digestate from biogas plant may be used. In this research, for the first time, we tested the feasibility of increasing biogas yield and rate from OWFI digestion by adding BC, which was produced from biogas plant digestate via torrefaction. The proposed proof-of-the concept refers to an approach of biogas plant waste transformation to BC and its recirculation gaining the higher biogas production, and waste recycling (Figure 1).




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Figure 1. Synergy of the waste to carbon with waste to energy concept

Materials and methods Multi-co-fermentation of OWFI consisted of:

• waste from the slaughterhouse (30 % w.m.),

• waste from vegetables and fruits processing (30 % w.m.),

• pulp from sugar production (20 % w.m.),

• waste from milk processing (10 % w.m.),

• waste from potatoes processing (10 % w.m.).

OWFI was fermented in the presence of BC with BC/(OWFI+BC) weight ratio:

• 0 % d.m., • 1.25 % d.m., • 2.5 % d.m., • 5 % d.m. , • 10 % d.m.

Biochar was produced from digestate from biogas plant in Świdnica, Poland. Torrefaction under 300oC for 60 minutes was applied. The process of anaerobic digestion was carried out in mesophilic conditions (38oC) in accordance with the German standard DIN 38414-S8.

Figure 2. Eudiometers used for biogas potential determination.

The research stand consisted of a set of 30 stationary fermenters, so-called eudiometers immersed in a water bath (Figure 2). Each of the fermenters had the same amount of solution- approx. 400 g. The quantity of substrates and BC was designed in such a way that the dry mass of the feed in the fermenter was always 5%. The following analyses were carried out in the OWFI samples:

• dry matter content in accordance with PN-EN 14346: 2011,

• loss on ignition and ash content in accordance with PN-EN 15169: 2011.

The amount of biogas produced in the initial phase of the anaerobic digestion process was recorded several times a day, along with the decreasing intensity of biogas production in the later days’ readings were made once a day. The biogas composition (content of CH4, CO2, O2, H2S, NH3) was measured using GA 5000 analyzer. The temperature and air pressure in the lab were recorded for further conversion of the biogas production results under normal conditions. The biogas kinetics were evaluated according to first order formula:

𝐺 = 𝐺0 ∙ (1 − 𝑒−𝑘 ∙𝑡) G - yield of biogas from the substrate at time t, Nm3∙Mg-1VS Go - the potential of biogas production from the substrate, Nm3∙Mg-1VS k - a constant rate of biogas production, d-1 t - time, d. Results The results of the feedstock properties before and after fermentation are given in table 1. Results of biogas production kinetics are given in table 2 and figure 2. The conducted experiment showed that applied mixture of OWFI had a high potential for methane fermentation. The biogas yield from OWFI without the addition of BC was 699.6 Nm3.Mg-1 VS, with the methane content 62.9 % v/v. The highest biogas production potential 721.5 Nm3.Mg-1 VS was found for variant with the addition of 2.5 % BC. Simulations, indicated that the addition of 2,5% of BC, may increase the power of the biogas

OWFI Biogas Plant

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o B

C

pro

du

ctio

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BC

Animal

feedstock

Composting

Cogeneration

Electricity

Heat?

Heat to biochar production

Cogeneration

Electricity

GR

IDG

RID

GR

IDG

RID

GR

ID

Biogas yield

Biogas yield




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plant with capacity of 30000 Mg OWFI per year by 2%. Moreover, this approach, with BC produced from digestate for recirculation to fermentation bioreactor, may high potential for application, as it utilizes the digestate itself and increases the degree of heat recovery from biogas cogeneration units. Table 1 The basic properties of feedstocks before and after the fermentation process

Variant

Before the experiment

After the experiment

DM, %

VS, %DM

DM, %

VS, %DM

OWFI 5.25 80.83 6.92 68.94

OWFI+BC1.25% 5.11 79.78 5.12 68.85

OWFI+BC2.5% 5.16 79.83 5.81 69.18

OWFI+BC5% 5.22 79.40 5.30 68.85

OWFI+BC10% 5.18 78.94 5.54 69.13

Inoculum 3.36 70.32 5.90 68.02

Figure 3. The cumulative curves of biogas production

Based on the experiments carried out and the results obtained, modeling was carried out, the purpose of which was to simulate the efficiency of the biogas plant with a capacity of 30000 Mg per year (Tab. 3). Table 4 The kinetic parameters of the OWFI fermentation process, k – constant rate, G0 – biogas potential production

Variant Biogas production

kinetics

k, d-1 G0, Nm3.Mg-1VS

OWFI 0.239 715.6

OWFI+BC1.25% 0.212 701.3

OWFI+BC2.5% 0.227 727.3

OWFI+BC5% 0.229 700.5

OWFI+BC10% 0.235 721.8

Table 3 The results of biogas plant simulation

Variant Biogas flow, m3.h-1

Electric power, MWe

CH4 content, %

OWFI 403.8 1.01 62.9

OWFI+BC1.25% 395.8 1.00 63.4

OWFI+BC2.5% 410.4 1.03 63.1

OWFI+BC5% 395.3 0.99 62.9

OWFI+BC10% 407.3 1.01 62.2

Conclusions The addition of small amount of biochar (BC, produced via torrefaction of digestate) to OWFI improves the biogas production efficiency. However, no proportional dose-effect dependence or an optimal BC dose at this stage of research was found. Still, this proof-of-the-concept research on the effect of the BC addition to determining the biogas production with the GB21 method allowed to conclude that:

• The addition of BC reduced the biogas production constant rate, which for OWFI variant were 0.239 d-1, respectively. The highest biogas production constant rate (k) resulted due to the 10% BC addition, and it was 0.235 d-1.

• The OWFI has high biogas production potential 715.6 m3∙Mg-1VS.

• The 2,5% BC dose resulted in the increase of the maximum production of biogas from the substrate (G0) of 727,3 m3∙Mg-1VS.

• Simulations, indicated that the addition of 2,5% of BC, may increase the power of the biogas plant with




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capacity of 30000 Mg OWFI per year by 2%.

• It is recommended to continue the research focused on other types of biochar especially those produced under higher temperatures.

• It is also recommended to investigate the mechanism of biochar addition on methane fermentation process, influence on microbial activity, and biogas net yield due to chemical-physical interactions with biogas components.

Acknowledgments

The research was done under financial support of the project titled ‘The development of an innovative, effective method of biomass biological treatment under an anaerobic condition’ implemented under the Bon for Innovations program. Project number: POIR.02.03.02-10-0024/18. References Dudek M, Świechowski K, Manczarski P, Koziel J.A, Białowiec A. The effect of biochar addition on the biogas production kinetics from the anaerobic digestion of brewers’ spent grain. Energies, 2019;12,1518.




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Increased energy efficiency and renewable energy use for high temperature heating

Danijela Urbancl1,*, Jurij Krope1, Darko Goričanec1 1University of Maribor, Faculty of Chemistry and Chemical Engineering, Maribor, Slovenia; *corresponding author email: [email protected] Abstract High-temperature heating is identified as one of the most challenges issues at regional and local level due to the high use of non-renewable energy sources and a very low share of renewable energy sources. In order to improve energy efficiency and the use of renewable energy sources for high-temperature heating, innovative technical solutions are needed. The aim of the research is to increase the fuel efficiency (natural gas, diesel, LPG, etc.) using renewable energy sources for high-temperature heating. The increase in fuel efficiency depends on the efficiency of CHP (cogeneration, combined heat and power system) and HP (heat pump) and can reach up to 220% in relation to LHV (low heating value) of fuel and with that equivalent CO2 emission reduction into the environment. The new heating system use low-temperature renewable energy sources (groundwater or any other waste heat) with a heat pump (HP). The produced heat is used for preheating the return water of the high temperature heating system to a maximum of 60°C and then water reheating at the required temperature with cogeneration system (CHP). The use of electricity produced by CHP is predicted for the HP compressor operation. The implementation of new heating system will reduce the dependency on the import of primary energy and will have positive effects on better air quality. Keywords renewable energy sources; high temperature heating; cogeneration; heat pump; energy efficiency Introduction

Controlling Europe's energy consumption and increasing energy consumption from renewable sources, including energy savings and increased energy efficiency, are an important part of the package of measures needed to reduce greenhouse gas emissions in accordance with the Kyoto Protocol, the United Nations Convention on Climate Change and the continued commitment of the Community and international commitments to reduce greenhouse gas emissions after 2012 (Urbancl at.al, 2015, Trop at.al. 2016, Urbancl at. al 2016).

High-temperature heating of buildings is identified as one of the most challenges issues at regional and local level due to the use of non-renewable energy sources and a very low share of the use of renewable energy sources.

Nowadays hot-water boilers and cogeneration devices are mainly used for high-temperature heating in buildings, which mostly use energy from non-renewable energy sources.

High-temperature heat pumps can also be used for high-temperature heating of buildings, which, in the case of exploiting a low-temperature heat source due to the high electricity cost of electricity from the electricity grid and the low COP, are not economically efficient.

In order to increase energy efficiency, a patented (Goricanec, 2017) innovative technical solution was developed to increase energy efficiency and the use of renewable energy sources for high-temperature heating of buildings. The solution consist of gas cogeneration units with an integrated additional heat exchanger for the production of waste heat by condensation of moisture present in flue gases and a low temperature




76

heat pump which will use heat of groundwater or surface water. New heating system

The innovation (Figure 1) envisages the

use of low-temperature renewable energy sources (groundwater) with a heat pump (HP) type water / water used for preheating the return water of the high temperature heating system to a maximum of 60°C and then water reheating at the required temperature with mini cogeneration system (CHP). For the HP compressor operation, the use of electricity produced by mini CHP is foreseen.

Figure 1. Schematic presentation of an innovative technical solution for high-temperature heating of buildings.

Legend: F- Fuel E- Environment P – Pipe Mini CHP – Mini Combined Heat and Power EC- Electric Cable HP – Heat Pump HA – Heat Accumulator HC – Heat Consumer

Single-Stage compression heat pump

Single-stage heat pumps are suitable for lower temperature differences between heat source and the required temperature of the heating medium.

We distinguish different types of heat pumps by source and heated medium (water-water, air-water), where the first place is always a source of heat on the other being a heated medium.

The compression heat pump (Figure 2) consists of a compressor, an expansion valve and two heat exchangers, where one evaporator is the other being a condenser. In the heat pump there is a coolant.

Figure 2. Schematic presentation of single – stage compression heat pump

The compressor serves to raise the

pressure of refrigeration vapour. In the condenser refrigerant vapours condensed. The expansion valve regulates the pressure in the evaporator and thus the temperature of the evaporating coolant.

With the circular process the heat source is cooled into the evaporator, heating medium, which is usually water heated by means of condensation cooled in the condenser. As a source of heat, waste heat, geothermal water, air, and groundwater, soil etc.

Fourth - generation refrigerant In heat pumps, more than 100 different refrigerants have been used, but there are only a few of them that produce satisfactory results and are not dangerous to use and the environment.

Ever since halogenated hydrocarbons have been banned in the field of refrigerants, there have been very high research towards the search for alternative environmentally friendly refrigerants that have low ODP (ozone depletion potential) and GWP (Global warming factor) .

In 2011, the European directive adopted the removal of fluorinated coolant from GWP greater than 150 in cars manufactured after 1. 1.2017




77

A lot of water/water low temperature heat pumps are on the market. They use unfriendly refrigeration substances R134a (GWP = 1430) or R407c (GWP = 1610)

In the developed process new and environmentally friendly refrigerant of fourth generation is used 1, 3, 3, 3-Tetrafluoropropane (HFO-1234ze), having GWP = 4 or 2, 3, 3, 3-Tetrafluoropropane (HFO-1234YF) with GWP < 1.

A heat pump with a fourth-generation coolant can also be used in the summertime to produce cold water for the needs of cooling spaces through the climates.

Table 1 presents values of GWP and ODP and some other physical properties of the proposed refrigerants. It is due to the low value of GWP and similar physical characteristics as it has cooled R134a

Table 1 Refrigerants properties

Refrigerant R134a R1234yf

R1234ze

ODP 0 0 0

GWP 1300 <1 4

Period of decomposition in atmosphere (years)

13,8 0,03 0,03

Boiling temperature(°C) -26,07 -29,45 -18,95

Critical temperature (°C) 101,1 94,7 109,4

Critical pressure(bar) 40,5 33,8 36,4

Use of fourth – generation coolant There is a problem by using the fourth generation refrigerant, because refrigerant vapours could condense in compressor. The solution to this problem is schematically shown in Figure 2.

Figure 3. Schematic presentation of single – stage compression heat pump with new refrigerant

Before entering the compressor the

vapours must be overheated. The vapours of R1234yf must be overheated for 2°C and R1234ze vapours must be overheated for 4°C.

The impact of the vapour overheating on the heating number and heat flow heat pump has been recalculated by computer simulation. From the results of the computer simulations, it was found that heating number (COP) increased by approximately 0.4, with a very small increase in the necessary energy to drive the compressor.

MINI CHP Mini CHP devices are used for cogeneration of heat and high-efficiency power. Natural gas is usually used as fuel.

The mini CHP of the TEDOM producer is used in the presented heating system. Technical data are given in Table 3.

Table 3 Technical data of MINI CHP

Modifications Standard Condensed

Electric power (kW) 6,5 6,5

Heat flow (kW) 16,0 18,4

Fuel consumption (kW) 24,1 24,1

Electric efficiency (%) 27,0 27,0

Heat efficiency (%) 66,3 76,4

Entire fuel efficiency (%) 93,3 103,4(2)

Heat accumulator

Standard commercially available heat accumulator is integrated in the process. At a




78

temperature difference of 1°C, 1 m3

accumulates 1,1 kWh / m3 of heat. The predicted temperature difference

between the inlet (70 ° C) and the return (35 ° C) of the heating system is ΔT = 35 ° C. The heat accumulator type CAS 5002 has a volume of 5 m3, which means that it can accumulate 192.5 kWh of heat.

Conclusions

New technology composed of a cogeneration plant and a low temperature heat pump for increasing the energy efficiency of primary fuel and the use of low-temperature renewable energy sources for high-temperature heating of buildings is developed.

The entire plant increases the total utilization of primary fuel used to drive the cogeneration system by more than 70%, depending on the efficiency of the primary fuel with the gas condensing boiler, and the same percentage reduces the CO2 emissions into the environment

New developed heat pump, which, will use a new and environmentally-friendly coolant of the fourth generation 1,3,3,3-dimethyl-4-fluorocarbon instead of the classical environmentally unfavourable refrigerants R134a (GWP = 1430) or R407c (GWP = 1610) is integrated in the process.

References Urbancl D, Zlak J, Anicic B, Trop P, Goricanec D. The evaluation of heat production using municipal biomass co-incineration within a thermal power plant. Energy 2015. doi:http://dx.doi.org/10.1016/j.energy.2015.07.064. Trop P, Agrez M, Urbancl D, Goricanec D. Co-gasification of torrefied wood biomass and sewage sludge. Comput. Aided Chem. Eng., vol. 38, 2016, p. 2229–34. doi:10.1016/B978-0-444-63428-3.50376-3. Urbancl D, Trop P, Goricanec D. Geothermal heat potential - the source for heating greenhouses in Southestern Europe. Therm Sci 2016;20:1061–71. doi:10.2298/TSCI151129155U. GORIČANEC, Darko. Method and apparatus for increasing the efficiency of the cogeneration power plant by the heat pump principle utilization for increasing the coolant inlet temperature: SI 25205 (A), 2017-11-30. Ljubljana: Urad Republike Slovenije za intelektualno lastnino, 2017. patentna družina: Patentna prijava št. P-201600123, 2016-05-05; WO2017191505 (A1), 2017-11-09; WO2017191505 (A4), 2018-02-22; PCT/IB2017/000574, 2017-05-05; CA3023380 (A1); CN109477642 (A); EP3452758 (A1); SI20160000155, 2016-06-20




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Photovoltaics design and synergy with landscape: multifunctional land use nexus between renewable energy production and water supply

Teodoro Semeraro1,*, Alessandro Pomes2, Amilcare Barca1, Cecilia Del Giudice3, Marcello Lenucci1,

Roberta Aretano4, Alessandra Scognamiglio5

1University of Salento, Department of Biological and Environmental Sciences and Technologies,

Ecotekne, Lecce, Italy; 2Technital SpA, Verona, Italy, Via Carlo Cattaneo 20, 37121; 3Global Solar Fund

Engineering Italy s.r.l., Brindisi, Italy, Viale Regina Margherita 13, 72100; 4Environmental consultant,

via S. Leucio 15, 72100 Brindisi Italy; 5ENEA, Italian National Agency for New Technologies, Energy and

Sustainable Economic Development, Energy Technologies Department, Portici Research centre, Portici

(NA), Italy, largo Enrico Fermi 1, 80055; *corresponding author email: [email protected]

Abstract The design of ground photovoltaic systems (GPV) mainly considers the engineering aspects. This is due to a design gap between engineering solutions for production of renewable energy and ecological or landscape issues. In this perspective, we propose to apply the design approach of PV in association with the multifunctional land use creating a nexus between renewable energy production and enhancement of ecosystem services. In this case, we redesign two PVs in Apulia Region to combine renewable energy production with an ecosystem able to support fresh water, treat wastewater, CO2 adsorption and biodiversity. Keywords green infrastructure; constructed treatment wetland; water reuse; ecosystem services; ground

photovoltaic systems

Introduction The need to make energy production not linked to fossil fuels to counteract climate change has led to the development of energy policies that encourage the use of renewable sources. However, many renewable energy projects have been developed with the only vision on energy. Many times, similar projects have been implemented in different areas. This has created a paradox, because policies designed to combat climate change have produced land-use change with negative effects on human well-being (Semeraro et al., 2018; Semeraro et al., 2017).

In recent years, there has been a competition between land use for agriculture and land use for the installation of ground photovoltaic systems (GPVs) with a loss of ecological functions that support the human benefits, defined as ecosystem services.

Currently, the design of GPVs is majorly focused on the management of the full spaces, that is where the panels are positioned, without giving importance at the design of the “pore” space, that is “the space around” or “the space in between” the modules (Scognamiglio et al., 2016). This is due to a design gap between engineering solutions for the production of renewable energy and ecological or landscape issues.

Our aim is to imagine and propose ground photovoltaic systems as green infrastructures able to create greater socio-economic and ecological harmony in the land use transition. This is important for developing strategies for multifunctional use of the land and improving the ecological performance of ground base photovoltaic systems. Main body




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As well as energy policies have an effect on

climate change, climate change affects the

availability of water resources. Recently, the

first real water crisis occurred in a metropolis

like Cape Town in early 2018. The population

lived daily with 50 litres of water per day. The

inhabitants had to adapt their daily habits. The

main security problem was the water theft.

In Apulia region, in south Italy, in

recent years there is a problem of availability of

water resources. There is a strong water crisis

especially in the summer period when the

demand for water increases for tourism and

the wastewater treatment plants are unable to

dispose of the quantity of wastewater

received.

So, the question we need to ask

ourselves is: how much will water cost after a

water crisis? How will our habits change?

Some experts consider the wastewater

reuse an important strategy for improved

water sector management.

In this perspective, we propose to

apply the design of GPVs with a multifunctional

land use approach creating a nexus between

renewable energy production and

enhancement of ecosystem services able to

support water reuse. This is done through a

study of a new pattern for GPVs, in which

energy generation is coupled with other

ecological functions.

Methods The main type of vegetation growing in the ground photovoltaic systems in the Apulia region is reuderal and nitrophilous flora, which has no significant ecological value. Its presence is encouraged by human disturbance. Companies spend about € 3,300 / MWp per year to remove it.

The idea is simple and consists in replacing the vegetation that grows spontaneously in PVs with vegetation capable of supporting specific ecological functions and, therefore, ecosystem services like fresh water, waste treatment and climate regulation

We try to apply our idea of design in two existing PVs in Apulia Region, maintaining

the same existing a) technology, b) energy production capacity and c) surface of the ground base photovoltaic systems. GPVs are made with solar tracking technologies and the panels are raised off the ground.

The projects have been developed adopting a transdisciplinary approach in order to involve a management system for taking into account the main economic, ecological and social aspects while avoiding trade-off among them. Results Figure 1 is the conceptual model of constructed treatment wetland that we have designed to build in existing photovoltaic systems.

Figure 1. Figure 1. Conceptual scheme of a high-efficiency constructed treatment wetland. SFS-h is Subsurface Flow System – horizontal; SFS-V is Subsurface Flow System – vertical and FWS is Free Water Surface (Salvati et al., 2012)

In the first case we were able to realize

the constructed treatment wetland by positioning the SFS-h and the SFS-v in the free space of the GPV. Here we have no specific limits in the choice of vegetation. Commercial

SFS-h (A)

SFS-v (B)

FWS (C)

A BC




81

species such as cannabis light or other varieties for specific aim could also be used. While the FWS is realized integrated with the solar panels, FWS also acts as a collection basin for purified water that can be used for various purposes (Figure 2 [1]).

In the second example, all the components of the constructed treatment wetland are integrated with the solar panels. In particular, by repositioning the panel rows it is possible to use vegetation about 1 mt in height. in this case it would also be possible to use vegetation with commercial value (Figure 2 [2]).

The economic costs for the construction of the different components that make up the wastewater treatment can be paid off through greater energy production, due to the capacity of the photovoltaic panels to use sun rays reflected from the water bodies. Then, direct and indirect ecological and social benefits have to be considered to which an economic gain can correspond: cost savings for water treatment compared to industrial plants; the capacity of these plants to absorb carbon dioxide; the possibility of providing clean water that can be used for human purposes. There are other indirect advantages that cannot be evaluated economically but that are important, for example, to support for biodiversity. In fact, a study conducted in a constructed treatment wetland has demonstrated the ability of these plants to support local and migratory birds (Semeraro et al., 2015). Indirectly, this plant can support other economic activities such as the production of starch from the Lemna minor (it is up to five times higher than corn) useful for bioethanol production and food production (Lee et al., 2016) or even the breeding of small fish for the purpose of environmental monitoring and aquaculture twchnologies.

This type of system can be modulated for different needs: from civil water treatment to industrial water treatment. This approach design can be used in countries characterized by a strong water crisis and poor accessibility to energy, in fact there are many populations that cannot regularly use electricity.

Figure 2. Example of two projects that integrate a photovoltaic system and constructed treatment wetland

Discussions We think that the philosophy of green infrastructure, through the input of renewable energy production, can push private individuals to indirectly invest in public services and

A

A

B

C

C

1

A

A

B

C

C

2




82

strategies that public administrations are not capable of realizing due to the economic crisis. Photovoltaic systems, made as green infrastructures, can represent a functional element of the landscape that can encourage sustainable development. In this way, PVs can be a "sink" of biodiversity: biodiversity spreads from the outside to the inside the PVs; at the same time, a source of biodiversity: biodiversity spreads from the inside the PV to the outside. This is an important aspect because it involves energy policies with policies for the development of biodiversity at european level (Figure 3).

Figure 3. Ground based photovoltaic systems thought like green infrastructures can represent an ecological functional element of the Landscape.

Conclusions We hope for a cultural transition in the design of renewable energy plants from a mono or interdisciplinary approach, that many times has led to a copy-and-paste in the plant design, i.e. using the same project in different places, to a transdisciplinary approach where every contribution is used to produce a holistic vision in the project, and involving both the private and the public sector. Innovation in this case consist in doing the same things but in a different way.

Green infrastructures are strategies able to produce new energy economy through Increasing the carrying capacity and reducing

the ecological footprint of urban systems by developing ecological functions that support the well-being of the population and that we can define as ecosystem services. Moreover, this type of vision of photovoltaic systems can also produce ecological and economic benefits not directly programmed but useful for increasing the multi-functionality of land use. References Salvati S, Bianco A, Bardasi G, Mirella C, De Mattia MC, Giovinelli L, Canepel R, Natalia MC. Guida tecnica per la progettazione e gestione dei sistemi di fitodepurazione per il trattamento delle acque reflue urbane (Technical guide for the design and management of phytodepuration systems for urban wastewater treatment), ISPRA 2012. http://www.isprambiente.gov.it/it/pubblicazioni/manuali-e-linee-guida/files/manuale [accessed 21 March 2018]. Scognamiglio A. ‘Photovoltaic landscapes': design and assessment. A critical review for a new transdisciplinary design vision. Renew Sustain Energy Rev 2016; 55:629–661. Semeraro T, Aretano R, Pomes A. Green Infrastructure to Improve Ecosystem Services in the Landscape Urban Regeneration. IOP Conf. Series: Materials Science and Engineering 2017; 245:082044 Semeraro T, Pomes A, Del Giudice C, Negro D, Aretano R. Planning ground based utility scale solar energy as green infrastructure to enhance ecosystem services. Energ Policy 2018; 117:218-227, 2018. Semeraro T, Giannuzzi C, Beccarisi L, Aretano R, De Marco A, Pasimeni MR, Zurlini G, Petrosillo I. A constructed treatment wetland as an opportunity to enhance biodiversity and ecosystem services. Ecol Eng 2015; 82:517-526. Lee CJ, Yangcheng H, Cheng JJ, Jay-Lin Jane. Starch characterization and ethanol production of duckweed and corn kernel. Starch/Stärke 2016; 68: 348-354.

Arable

land

PV

PV

PV

PV

PV

Olive

groves

source

sink

Photovoltaic systems can become an island of biodiversity in an mono-

agricultural landscape

biodiversityflow

Agriculturalfield

PhotovoltaicSystem (PV)




83

Experimental research and simulation of computer processes of heat exchange in a heat exchanger working on the basis of the principle of heat

pipes for the purpose of heat transfer from the ground

Łukasz Adrian1,*, Szymon Szufa2, Piotr Piersa3, Krystian Kurowski4 1Cardinal Stefan Wyszyński University in Warsaw, Faculty of Biology and Environmental Sciences, Warsaw, Poland; *corresponding author email: [email protected] address: Lokajskiego 1A, 98-200 Sieradz, Poland; 2Lodz University of Technology, Faculty of Process and Environmental Engineering, Lodz, Poland; 3Lodz University of Technology, Faculty of Process and Environmental Engineering, Lodz, Poland; 4Cardinal Stefan Wyszyński University in Warsaw, Faculty of Biology and Environmental Sciences, Warsaw, Poland Abstract The article presents the results of experimental research and simulation of computer processes of heat exchange in a heat exchanger working on the basis of the principle of heat pipes for the purpose of heat transfer from the ground. The article presents the results of experimental tests at the experimental stand and computer simulations of the effects of heat exchange and phase transformations, both on the heat supply side and on the heat pickup side in order to build them from above. a heat source heat exchanger that allows efficient transport of heat from the ground. The final result of the conducted tests are the results of measurements and characteristics of heat exchange processes and the actual efficiency of analyzed heat exchangers, such as heat pipes made of copper, 1780 mm long and 18 mm in diameter. One of the main assumptions was the analysis and evaluation of the heat pump's efficiency for various working factors and related phase transitions as well as in different temperatures in the range of 5-50 ⁰C both on the heat supply side and heat reception. The heat streams collected and given off by the heat pipe during the operation were examined, which in the selection of the optimization criterion in the form of type and amount of working medium resulted in the efficiency of the heat pipe exceeding 90% with heat streams reaching 200 W. The article presents research issues necessary for the analysis of the efficiency and usefulness of heat pipes as heat exchangers mounted in the lower heat sources of the central heating installation, including in air conditioning and construction engineering because the temperature range at the time of testing was 5-50 ⁰C, which coincides with the scope of work of heat exchangers working in the above-mentioned environments. Obtained satisfactory results of experimental tests in the size of heat streams collected and given by the heat pipe at the level of 200 W and its efficiency in heat transfer exceeding 90% on the one hand enable reduction of operating costs of central heating and cogeneration devices for heat and electricity production, on the other hand they enable their ecological work, which in turn will contribute to the reduction of CO2 emissions to the atmosphere. Keywords heat exchange; heat exchanger; heat pipe; renewable sources of energy; heat pump; heat from the ground; thermal efficiency Introduction One of the most popular devices using renewable energy sources are ground-source heat pumps. Geothermal pumps extract heat from the ground through a system of horizontal or vertical exchangers. In previously used ground heat pumps, the heat carrier is usually

a mixture of glycol with water, which in a positive temperature reaches the evaporator. In the glycolic concept presented in this article, the ground heat exchanger has been replaced with a highly efficient heat exchanger like a heat pipe. Heat Pipes are heat exchangers that were created as a result of efforts to intensify heat exchange processes. One of the main




84

advantages of heat pipes is their high efficiency, allowing the transfer of significant amounts of heat, even at a small temperature difference [3], [4].

The results presented in this paper will enable wider use of heat pipes to reduce primary energy consumption by reducing energy dissipation in heat exchange processes and through their intensification. The above-mentioned advantages of using heat pipes will significantly increase the efficiency of ground-source heat pumps, which perfectly fits into the activities limiting primary energy consumption and increasing energy efficiency [5].

The research results will contribute to the construction of ground heat exchangers with higher efficiency and efficiency than previously used, which in turn will contribute to a lower demand for electricity and heat, making heat pumps even less energy-intensive. Benefits resulting from the implementation of work results will consist in intensification of heat exchange processes and reduction of heat losses in heating buildings.

In this work, for the needs of ground heat exchangers, we will deal with gravity heat pipes. Gravitational Heat pipes consist of three separate areas: an evaporator, that is, a heat supply area, a condenser, i.e. a heat receiving area and an adiabatic area between them. The heat delivered to the evaporator area causes the working fluid in the evaporator to evaporate. The high temperature and correspondingly high pressure in this area creates a steam stream towards the opposite, cooler end of the vessel, whereupon the vapor condenses, giving off its latent heat of vaporization. Then, as a result of gravity, they transport the liquid back to the evaporator. As part of this work, a single heat tube test was carried out using working mediums such as R134A, R404A and R407C. These factors were chosen because of their thermodynamic properties in the studied temperature range, as well as the availability and affordable price of their use in construction engineering and air conditioning. Experimental tests were carried out under conditions corresponding to natural work, i.e. under temperature conditions of ground heat exchangers. The effects of phase transformations for the already mentioned

working factors and their number, as well as their influence on the work and efficiency of the heat pipe were examined. One of the main goals was to analyze and evaluate the heat pump's work efficiency for various operating factors at different temperatures on the heat supply side to the heat pipe. The experimental tests were carried out on a real copper heat exchanger, 1769 mm long, 18 mm outside diameter and 1 mm wall thickness. [1][6]. Methods The first tests were carried out for a tube with a vacuum inside and then filled with air to confirm the thesis of negligible heat conduction through the wall of the tube along its length. The research consisted in placing both the place of heat supply (ie evaporator) and the place of heat collection (ie condenser) in the flow exchanger, which supplies and receives heat from the heat pipe on the basis of a tube-type heat exchanger in the pipe. Modeling and numerical simulations of the work of heat exchangers like heat pipes constituted a correlation of experimental research results. Experimental tests and numerical simulations were carried out for heat-conducting working agents such as: R134A, R404A, R407C and for vacuum and air inside the heat tube under test. The heat pipe was filled in volume for subsequent measurements in an amount of: 2.5%; 5%; 10%; 20%; 30% and 40% of its entire volume. [2] Results Table 1 presents a comparison of the most favorable fillings of all examined operating factors. Figure 1 presents comparative graphs of heat streams collected and given up by the heat pipe and heat pipe efficiency for the best filling of all tested operating factors. Table 1 Comparison of the most favourable fillings of all tested operating factors

Tg1 [oC]

R134A 10% R404A 10% R407C 5%

Qg [W]

Qz [W]

ɳ [%]

Qg [W]

Qz [W]

ɳ [%]

Qg [W]

Qz [W]

ɳ [%]




85

15 30,76 27,73 90 24,17 20,03 83 0,44 0,00 0

20 39,48 35,65 90 37,29 31,70 85 0,88 0,00 0

25 63,48 57,88 91 59,11 51,72 88 13,13 1,76 13

30 83,05 78,33 94 78,68 71,85 91 34,93 11,23 32

35 104,6 99,04 95 109,0 100,7 92 54,47 34,12 63

40 134,9 127,6 95 135,1 124,2 92 84,84 61,64 73

45 160,7 151,8 94 154,5 140,7 91 128,1 97,97 76

50 199,3 184,8 93 176,0 150,8 86 162,5 126,6 78

Figure 1. Comparative graphs of heat streams collected and given up by a heat pipe and heat pipe efficiency for the best filling of all tested operating factors.

The CFD 2-D analysis presented in this

study was terminated using the ANSYS FLUENT ™ program. The CFD package was used for gas-liquid modeling and phase changes during evaporation and condensation. The 2-D geometry was provided with densification at the walls of the heat pipe, which enabled the modeling of the flow and heat transfer in the heat pipe. In the fluid area 60690 nodes and 29118 elements were created, while in the area of the solid body (walls) 9816 nodes of 3636 elements were used.

The results of computer simulations based on the numerical model of a heat pipe presented above are presented below. The results show graphical temperature distributions inside the heat pipe during its operation for the assumed boundary conditions. The simulations were carried out for the heat tube geometry indicated in the work and for the experimentally tested working factors.

Figure 2. Temperature distribution in the heat pipe a. - total heat pipe b. - evaporator section; c. - condenser section, d. - isothermal section

Discussions Based on the analysis of experimental studies, it can be concluded that the most effective working medium for the heat tube in the tested temperature range is R134A refrigerant with 10% filling of the heat pipe. With a water flow rate of 15 l / h for measured temperature differences, the heat flux drawn by the heat pipe reaches the value of 199.3W, while the heat flux transmitted through the heat pipe reaches the value of 184.8W. In this case, the evaporator is washed with water at 50 ° C. When working in the remaining temperature range, the R134A refrigerant in the 10% filling was also best placed. In addition to the largest heat streams passed through the heat pipe, this factor in the said filling achieved the best heat exchange efficiency of up to 95%. The R404A factor, also with 10% filling, proved to have a quite good influence on the effectiveness of the examined heat source, although it achieved worse results than the R134A factor. The worst factor was the R407C

0

20

40

60

80

100

120

140

160

180

200

15 25 35 45

Qg

[W]

tg1 [°C]

R134A 10% R404A 10% R407C 5%




86

factor, both in terms of transmitted heat flows and heat transfer efficiency through the heat pipe. Conclusions In most of the cases analyzed, the most effective working medium is R134A with a 10% filling of the heat pipe, followed by R404A also with a 10% filling. R407C turned out to be the least effective among the examined. The heat tube working with the R407C refrigerant is characterized by low efficiency of heat transport, low efficiency and the highest pressure values prevailing inside it during operation in a given temperature range. The results of computer simulations and calculations of the theoretical model correlated the results on the research stand.

The temperature distributions obtained as a result of computer simulations confirm the obtained experimental results. References

1. Łukasz Adrian, Szymon Szufa, Piotr

Piersa, Zdzisława Romanowska-Duda,

Mieczysław Grzesik, Artur Cebula,

Sebastian Kowalczyk, Joanna

Ratajczyk-Szufa, "Thermographic

analysis and experimentl work using

laboratory installation of heat transfer

processes in a heat pipe heat

exchanger utilizing as a working fluid

R404A and R407A" - Springer Nature

Switzerland AG 2019, M. Wróbel et al.

(eds.), Renewable Energy Sources:

Engineering, Technology, Innovation,

Springer Proceedings in Energy, pp.

799-807,

2. Łukasz Adrian, Szymon Szufa, Piotr

Piersa, Zdzisława Romanowska-Duda,

Mieczysław Grzesik, Artur Cebula,

Sebastian Kowalczyk, "Experimental

research and thermographic analysis

of heat transfer processes in a heat

pipe heat exchanger utilizing as a

working fluid R134A", Renewable

Energy Sources: Engineering,

Technology, Innovation, Springer

Proceedings in Energy

3. Zhangyuan Wang, Haopeng Zhang

Fucheng Chen, Siming Zheng, Zicong

Huang, Xudong Zhao. Heat Pipe and

Loop Heat Pipe Technologies and Their

Applications in Solar Systems,

Advanced Energy Efficiency

Technologies for Solar Heating, Cooling

and Power Generation

4. Benne K.S., K.O. Homan, Dynamics of

closed-loop thermosyphon

incorporating thermal storage,

Numerical Heat Transfer. Part A,

Applications 54 (3) (2008) 235–254.

5. Cioncolini A. and Thome J. R..

Algebraic turbulence modeling in

adiabatic and evaporating annular

two-phase flow, „International Journal

Of Heat And Fluid Flow”, vol. 32, p.

805-817, 2011

6. Grover, G.M., Cotter T. P., and Erickson G.

F. (1964). Structures of Very High Thermal

Conductance. „Journal of Applied Physics

35” (6): 1990–1991.

https://www.researchgate.net/scientific-contributions/72404625_Xudong_Zhao




87

The possibility of gaining profit on a rational management of digestate

Wojciech Czekała1,*, Patrycja Pochwatka2, Jakub Pulka1, Jakub Mazurkiewicz1, Damian Janczak1, Mo

Zhou3 1Poznań University of Life Sciences, Poznań, Poland; 2University of Life Sciences in Lublin, Lublin, Poland; 3Poznań University of Technology, Poznań, Poland; *corresponding author email: [email protected] Abstract Biomass is the most popular renewable energy source (RES) on all world, making an alternative for nuclear energy and fossil fuels. One of RES which is biogas production as an aerobic digestion process result. As a result of the process, the following products are created: biogas and digestate (digested pulp). Digestate has a liquid form and is usually used as a fertilizer directly. However, it should be remembered that there are other possibilities of its use. The work aims to determine the possibility of gaining profit from raw digestate from agricultural biogas plant and products based on it. The possibilities and profitability for sales of raw digestate and compost based on digestate solid fraction were analyzed. It can be concluded that the sale of raw digestate and fertilizers based on a solid fraction of digested pulp can bring additional income to the owners of a biogas plant. Keywords biogas production, renewable energy sources, digestate, fertilizer, environmental engineering

Introduction Renewable energy production and environmental protection are one of the most significant challenges at the moment (Wolna-Maruwka and Dach, 2009; Quek et al., 2018; Jóźwiakowski et al., 2017). One of the RES is biogas production as a result of the anaerobic digestion process (Dach et al., 2014; Czekała, 2017). The most important product of the anaerobic digestion that takes place in biogas plants is biogas (Waliszewska et al., 2018). It is a mixture of gases with a dominance of methane (Wandera et al., 2018). It should be remembered about the second product – digestate (digested pulp), which should be properly managed (Szymańska et al., 2019). The amount of produced digestate is related to the amount and type of substrates used for the production of biogas.

The most commonly used solution for the management of digestate is direct use as fertilizer (Czekała, 2018). The popularity of this direction is primarily due to the fact that no additional works such as separation or drying are required. This significantly affects the economic balance of the chosen method

(Czekała et al., 2018). The main disadvantage of this solution is usually the lack of sufficient areas for distribution of digestate. Therefore, other directions for digestate utilization are used (Czekała et al., 2017; Czekała et., 2018)

The key to using digestate in other ways is the separation process (Guilayn et al., 2019). After raw digestate separation, two significantly differentiated fractions are obtained. The liquid fraction is used like raw digestate as a fertilizer or for the hydration of new substrates. The solid fraction can be used, a.o. as a substrate for composting. Another way of digestate use as a fertilizer is the production of fertilizer granules in pellets form. However, this solution is not very popular, which results, a.o. at high costs associated with the separation, drying and forming of the product.

Apart from fertilization using digestate, there are also other directions, including mainly the production of pellets and briquettes, and then their use for energy purposes (Nagy et al., 2018).

The work aims to determine the possibility of gaining profit from raw digestate




88

from agricultural biogas plant and products based on it.

Methods For the purposes of this article, the results of digestate from agricultural biogas plants operating in Poland research were used. The main substrates used for biogas production in anaerobic digestion were maize silage, cow manure, cow slurry and agri-food industry waste. Selected physical and chemical properties were determined using the procedures in a certified laboratory.

The economic analysis of the digestate was based on the unit prices of selected mineral fertilizers according to methodology (Czekała et al., 2018). The NPK fertilizer prices have been used to calculate the cost of one kilogram of pure component (N, P2O5, K2O). Based on the calculations, the value of digestate from the biogas plant in an alternative approach to mineral fertilizers was estimated. For calculation purposes, a conversion rate has been adopted 1 PLN = 0,2330 EUR [July 31, 2019]. Results and discussions Organic and natural fertilizers such as digestate, compost, manure, or slurry are an alternative to mineral fertilizers. Their positive properties and lower price of acquisition are increasingly perceived. The analyzed digestate was characterized by proper fertilizing properties, which is confirmed by the data contained in Table 1. Table 1 The content of selected parameters in digestate [fresh matter].

Parameter Content

Dry matter [%] 6.2 pH [H2O] 8.2

Nog [kg/Mg FM] 4.0 P2O5 [kg/Mg FM] 1.0 K2O [kg/Mg FM] 4.0

The dry matter content in the examined digestate was 6.2%. The pH was 8.2 and was typical for digestate from agricultural biogas plants (Nkoa, 2014). The nitrogen

content was 4.0 kg∙Mg-1. The same amount

was for potassium based on K2O kg∙Mg-1. Of

the three most important macroelements, the lowest content was characterized by phosphorus. Calculated on the P2O5 oxide

form, the value was 1.0 kg∙Mg-1. The digestate is characterized by a

varied content of macroelements, which depends mainly on the type of substrates used for the production of biogas. There is a necessity to calculate prices in relation to 1 kg of pure component (N, P2O5 and K2O). These values were presented in table 2.

Table 2. Selected fertilizers for analysis together with their prices.

Fertilizer N, P, K

content

Fertilizer Mg price

Price per 1 kg of

comp-onent

[PLN]

Urea

46% N 1280 2.78

Single Superphosphate

19% P2O5

835 4.39

Potassium chloride

60% K2O 1290 2.15

On the basis of these results, the value

of particular macroelements was calculated. This allowed to estimate the value of the digestate. These values were presented in table 3. Table 3 The value of the analyzed digestate.

Price per 1 kg of component

[PLN]

Component content

[g·kg-1 FM]

Component price [PLN]

2.78 4.0 11.12 4.39 1.0 4.39 2.15 4.0 8.60

Total 24.11

Based on a simple calculation, the value of the analyzed digestate was estimated at PLN 24.11. Due to its physical and chemical properties, the digestate can be used in many ways, including directly as a fertilizer, which is related to the circular economy.

The use of digestate as a fertilizer is the most frequently practiced solution that allows its management (Timonen et al., 2019). The raw digestate is a liquid with a low content of dry matter, which rarely exceeds 10%. A common feature of digestate is also alkaline,




89

most often with a pH between 7.3-9 (Nkoa, 2014).

Own research (Czekała et al., 2017) and other authors (Torres-Climent et al., 2015) also confirm the possibility of using digestate for the production of compost. However, it is necessary to separate raw digestate. The obtained solid fraction, which is a bulk material not only improves the structure of the composted mixture. It is also a carbon source that has not decomposed under aerobic conditions.

The digestate being a waste or by-product of the anaerobic digestion process is a valuable substrate used primarily for agricultural purposes (Czekała et al., 2018). The price of the digestate should be conditioned mainly on the content of nutrients. In some countries, for example China or Vietnam, the sales revenues of fertilizer can reach a value similar to those obtained from biogas. A certain problem may be the prices of its sales determined by the local or national market. This is the case, a.o. in Poland, where the digestate is often not appreciated despite many studies and publications confirming its usefulness (Sogn et al., 2018). Bearing in mind the low fertility of soils in many countries of the world, it is recommended that the digestate is used primarily as a fertilizer. Such action, according to the circular economy principle, will help to improve the state of the environment and reduce financial outlay on mineral fertilizers. Conclusions The advantage of a biogas plant is the possibility of using both biomass and waste, which is important, for local production plants and processing plants. According to the authors, the research on the use and value of digestate is innovative, because its processing before its use is a relatively new issue and rarely practiced by biogas plant owners.

It can be concluded that the sale of raw digestate and fertilizers based on a solid fraction of digested pulp can bring additional income to the owners of a biogas plant. Based on the own research, scientific publications, considerations, talks with the owners of the biogas plant and fertilizer manufacturers

should expect a systematic development not only the biogas sector but also the digestate market. According to the authors, ganging a profit from the sale of digestate would be one of the factors allowing to increase the profitability of the building of a biogas plant.

Acknowledgments This study was performed as part of the statutory research no. 506.105.06.00 in the discipline of Environmental Engineering, Mining and Energetics, entitled "Energetic use of waste as a method of improving the environment". References Czekała W, Smurzyńska A, Cieślik M, Boniecki P, Kozłowski K. Biogas efficiency of selected fresh fruit covered by the Russian embargo. Energy And Clean Technologies Conference Proceedings, SGEM 2016;VOL III:227-233. Czekała W. Concept of IN-OIL project based on bioconversion of by-products from food processing industry. Journal of Ecological Engineering 2017;18(5):180-185. Czekała W, Dach J, Dong R, Janczak D, Malińska K, Jóźwiakowski K, Smurzyńska A, Cieślik M. Composting potential of the solid fraction of digested pulp produced by a biogas plant. Biosystems Engineering 2017;160:25-29. Czekała W., Bartnikowska S., Dach J., Janczak D., Smurzyńska A., Kozłowski K., Bugała A., Lewicki A., Cieślik M., Typańska D., Mazurkiewicz J. The energy value and economic efficiency of solid biofuels produced from digestate and sawdust. Energy 2018; 159: 1118-1122. Czekała W. Agricultural Biogas Plants as a Chance for the Development of the Agri-Food Sector. Journal of Ecological Engineering 2018;19(2):179-183. Czekała W, Janczak D, Wojcieszak D, Waliszewska H, Lewicki A, Smurzyńska A. Nutrient value of digestate from agricultural biogas plant in Poland. Proceedings of 2018 2nd International Conference on Green Energy and Applications ICGEA 2018 March 24-26, 2018 Singapore,10-13. Dach J., Czekała W., Boniecki P., Lewicki A., Piechota T. Specialised internet tool for biogas




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plant modelling and marked analyzing. Advanced Materials Research 2014;909:305-310. Guilayn F, Jimenez J, Rouezb M, Crest M, Patureau D. Digestate mechanical separation: Efficiency profiles based on anaerobic digestion feedstock and equipment choice. Bioresource Technology 2019;274:180-189. Jóźwiakowski K, Podbrożna D, Kopczacka K, Marzec M, Kowalczyk-Juśko A, Pochwatka P, Listosz A, Malik A. The state of water and wastewater management in the municipalities of the Polesie National Park. Journal of Ecological Engineering 2017;16(6):192-199. Nagy D, Balogh P, Gabnai Z, Popp J, Oláh J, Bai A. Economic Analysis of Pellet Production in Co-Digestion Biogas Plants. Energies 2018;11(5):1135:1-21. Nkoa R, Agricultural benefits and environmental risks of soil fertilization with anaerobic digestates: a review. Agronomy for Sustainable Development 2014;34(2):473-492. Quek A, Ee A, Ng A, Wah TY. Challenges in Environmental Sustainability of renewable energy options in Singapore. Energy Policy 2018;122:388-394. Sogn TA, Dragicevic I, Linjordet R, Krogstad T, Eijsink VGH, EichGreatorex S. Recycling of biogas digestates in plant production: NPK fertilizer value and risk of leaching. International Journal of Recycling of Organic Waste in Agriculture 2018;7:49-58. Szymańska M, Szara E, Wąs A, Sosulski T, Pruissen GWP, Cornelissen RL. Struvite—An Innovative Fertilizer from Anaerobic Digestate Produced in a Bio-Refinery. Energies 2019;12(2),296:1-9.

Timonen K, Sinkko T, Luostarinen S, Tampio E, Joensuu K. LCA of anaerobic digestion: Emission allocation for energy and digestate. Journal of Cleaner Production 2019;235:1567-1579. Torres-Climent A, Martin-Mata J, Marhuenda-Egea F, Moral R, Barber X, Perez-Murcia MD, Paredes C. Composting of the Solid Phase of Digestate from Biogas Production: Optimization of the Moisture, C/N Ratio, and pH Conditions. Journal Communications in Soil Science and Plant Analysis 2015;46(1):197-2017.Special Issue on the 13th International Symposium on Soil and Plant Analysis. Waliszewska H, Zborowska M, Waliszewska B, Borysiak S, Antczak A, Czekała W. Transformation of Miscanthus and Sorghum cellulose during methane fermentation. Cellulose 2018;25(2):1207-1216. Walsh JJ, Jones DL, Edwards‐Jones G, Williams AP. Replacing inorganic fertilizer with anaerobic digestate may maintain agricultural productivity at less environmental cost. Journal of Plant Nutrition and Soil Science 2012;175(6):840-845. Wandera SM, Qiao W, Algapani DE, Bi S, Dongmin Y, Qi X, Liu Y, Dach J, Dong R. Searching for possibilities to improve the performance of full scale agricultural biogas plants. Renewable Energy 2018;116:720-727. Wolna-Maruwka A., Dach J. Effect of type and proportion of different structure-creating additions on the inactivation rate of pathogenic bacteria in sewage sludge composting in a cybernetic bioreactor. Archives of Environmental Protection 2009; 35(3):87-100.




91

Comparison of the spatial distribution of agricultural biogas plants in relation to generated power

Patrycja Pochwatka1,*, Jacek Dach2, Jakub Pulka2, Wojciech Czekała2

1University of Life Sciences in Lublin, Department of Environmental Engineering and Geodesy, Lublin, Poland; 2Poznan University of Life Sciences, Institute of Biosystems Engineering, Poznan, Poland; *corresponding author email: [email protected] Abstract The paper aimed to compare different technologies of biogas production in order to find the most effective technologies in term of generated power related with surface taken by installation and whole terrain, which can be expressed in kW per m2 of biogas plant or per entire parcel. The results showed that this new parameter created for estimation of biogas plant efficiency estimation has proven its usefulness during comparison of different technologies and real objects. The results of coefficient power per surface have shown very high differences between analyzed technologies and installations. The worst results in the 3rd criterion of power surface coefficient were for the installations working on the NaWaRo technologies. This means that new technologies having better performance in this area will be more often choose by investors. Keywords biogas plant; power generation; spatial distribution Introduction Poland has one of the biggest potential for

biogas production in Europe (Dach et al., 2014;

Czekała et al., 2018). The analyses made by the

scientists from the Institute of Biosystem

Engineering, Poznan University of Life Sciences

have shown that amount of biowaste and

agricultural waste can reach yearly almost 130

million tons, which is the equivalent of 6000

MW of electric power or over 8 billion m3 of

biomethane. In consequence, the potential of

biogas sector is estimated between 4000 to

6000 installations with the electric power

between 0.5 to 2.5 MW. The most common

facilities are the 1 MW and 0.5 MW biogas

plants. Probably during the next years, also the

installations with those power scales will

dominate the Polish market.

There are several technologies actually

installed in Poland. The differences between

biogas (and methane) production efficiency,

used substrates, reliability and investment

costs were analyzed by many investors, bancs,

scientists and specialists (Wandera et al., 2018;

Waszkielis et al., 2013; Kowalczyk-Juśko et al.,

2015; Kozłowski et al., 2018). However, there is

very few information about spatial distribution

of agricultural biogas plants in relation to

generated power (Thompson et al., 2013).

Typically, the 1 MW biogas plant of electric

power needs the area between 2-3.5 ha. But so

large area influences on the investment costs

grow. So modern technologies have much

compact technical solutions and need less

space for the investment.

The aim of this paper was to compare

different technologies of biogas production in

order to find the most effective technologies in

term of generated power related with surface

taken by installation and whole terrain, which

can be expressed in kW per m2 of biogas plant

or per entire parcel (this second parameter

seems to be not so much valuable).

Materials and methods Chosen objects The Ecotechnologies Laboratory (EL) at Poznan University of Life Sciences is the biggest biogas




92

laboratory in Poland. With over 250 different-size fermenters, the EL has tested almost 2500 different substrates for biogas efficiency. The EL offers also technological support for planned to build as well as existing Polish biogas plant working in different technologies. This support contains continuous technological care as well as incidental help in case of fermentation problems. That is why EL has large knowledge about different Polish biogas plant and have also access to real production data from working installations.

In order to analyze the spatial distribution of agricultural biogas plants in relation to generated power, the list of seventeen biogas plants were taken from the register of the agriculture biogas producer.

The Authors have chosen biogas plants with additional data about real energy production in order to compare the energetic efficiency by square meter based also on real data.

The analyzed installations work are in different sizes (0.400-2.199 MW of electric power) in different technologies, as follow:

- NaWaRo and its clones (12

installations);

- DynamicBiogas (4 plants, including 1

installation of 3rd generation);

- ProBioGas (1 installation).

Spatial analysis In order to reach the aim of the work, it was necessary to measure the biogas parcels, fermenters and other objects which are placed there. Using the data from geoportal.gov.pl it was possible to determine:

- area of the total parcels;

- location of objects on parcels;

- surface of objects on parcels.

Analyzing the biogas plants and all buildings and installation parts, we have distinguished three groups of objects: a) Elements of installation responsible for fermentation and energy production: - F – fermenters - C – co-generator for electric energy and heat production. b) Objects supported the exploitation of installation:

- SP – a storage place for substrates (i.e., silage); - DT – digestate tanks; - TLS – tanks for liquid substrates; - TB – technical buildings. c) Other objects (not directly connected with biogas production): - OB – other objects. In order to calculate exact surface of parcels and all objects, different geodetic data were used, like follow:

- satellite images (orthophotomaps);

- data register of land and buildings;

- basic map elements – geodetic

records of public utilities.

Figure 1. Elements of biogas plant identified on the satellite image

Geoportals allow to display publicly

available data and with adequate knowledge to perform the necessary analysis (De Longueville, 2010). Preliminary identification of infrastructure elements (Fig. 1) and subsequent measurements made on the map (Fig. 2) allowed to obtain approximate dimensions and surfaces of the analyzed elements.

Figure 2. Measurements of biogas plant elements – technical building and digestate tank

The installed electric power was divided by:




93

- total parcel surface of analyzed

biogas plant;

- the surface of indispensable and

supported objects of installations;

- the surface of installation elements

indispensable for fermentation

and energy production

(fermenters and co-generators).

The Authors want to underline, that

this 3rd parameter (kW/m2) of the surface of installation elements indispensable for fermentation and energy production is the most important parameter to estimate the biogas plant efficiency for all analyzed technologies and objects. Results It has to be underlined that the analyzed biogas plants have different installed power, used different substrates and in consequences some of them have additional storage areas (silos, concrete platforms or tanks for liquid substrates).

In table 1, the lists of all analyzed biogas plants is shown.

Table 1 The list of analyzed biogas plants with its power.

Biogas plant No.

Technology used

Installed electric power [MW]

1 NaWaRo 0.999

2 Dynamic Biogas 0.999

3 NaWaRo 2.126

4 NaWaRo 0.999

5 NaWaRo 2.126

6 ProBioGas 2.199

7 NaWaRo 0.999


9 NaWaRo 1.897

10 NaWaRo 0.999

11 NaWaRo 0.999

12 NaWaRo 1.560


14 NaWaRo 0.999

15 NaWaRo 0.999

16 NaWaRo 0.999


The analysis have shown that the differences between analyzed objects were very high (table 2). The most common parcel surface

taken by 1 MW of electric power installation was around 3 hectares (+/- 1 ha). Table 2 Results obtained depending on the criterion set.

Biogas plant No.

1st

criterion [kW/m2]

2nd

criterion [kW/m2]

3rd

criterion [kW/m2]

1 0.07 0.25 0.86

2 0.03 0.16 1.86

3 0.02 0.08 0.68

4 0.04 0.13 0.88

5 0.27 1.27 1.98

6 0.11 0.27 1.39

7 0.04 0.18 1.02

8 0.15 0.60 1.76

9 0.08 0.34 1.35

10 0.03 0.12 0.95

11 0.02 0.11 1.06

12 0.04 0.10 1.02

13 0.04 0.46 1.92

14 0.03 0.10 0.85

15 0.04 0.15 0.82

16 0.05 0.18 1.26

17 0.06 0.22 1.75

Surface taken by the installation itself

(fermenters, tanks for digestate, technical buildings) take between 350 to 400 m2. This an equivalent of 2.2 – 2.9 kW per m2. However, new generations biogas plant can reach much higher parameter up to 6.4 kW per m2 (case of Przybroda biogas plant). Discussions From an energetic point of view, Polish biogas sector has huge development potential within the next decade. This is related to biomass and biowaste availability from the biogas plant, which is estimated at almost 130 mln Mg/a. Thus, it is equivalent of several thousand installations with power 0.5-1 MW. However, one of the limits for sector grow is relatively small availability of industrial parcels which can be used for building biogas plant. Additionally, the square meter cost of parcels for industrial purposes is several times more expensive than typical agriculture ground. Taking into account the high ground prices, the investors should look for the biogas technologies which can be run on parcels with smaller size. The technologies analyzed in this paper clearly show the huge differences in the energetic




94

efficiency of installations related to the surface. For the future, the development of “peak installations” (working i.e., 15 h/day) instead of working continuously (24 h/day) seems to be especially attractive for investors. In their case, peak installations will reach coefficient power per surface even several dozen percent better than best linear installations. Conclusions

Based on the performed research, the followed conclusions were created:

New parameter (“power per surface”,

kW/m2) created for estimation of biogas

plant efficiency has proven its usefulness

for comparison of different technologies

and objects working in real scale.

The results of coefficient power per surface

have shown very high differences between

analyzed technologies and installations.

The worst results in the 3rd criterion of

power surface coefficient were for the

installations working on the NaWaRo

technologies. This means that new

technologies having better performance in

this area should be more often chosen by

investors.

Future development of biogas plant

working in “peak mode” will increase the

coefficient power per surface by several

dozen percents.

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Advanced Materials Research 2014;909:305-310. Czekała W, Bartnikowska S, Dach J, Janczak D, Smurzyńska A, Kozłowski K, Bugała A, Lewicki A, Cieślik M, Typańska D., Mazurkiewicz J. The energy value and economic efficiency of solid biofuels produced from digestate and sawdust. Energy 2018; 159: 1118-1122. Kowalczyk-Juśko A, Kościk B, Jóźwiakowski K, Marczuk A, Zarajczyk J, Kowalczuk J, Szmigielski M, Sagan A. Effects of biochemical and thermochemical conversion of sorghum biomass to usable energy. Przemysł Chemiczny 2015;94(10):1000-1002. Kozłowski K, Mazurkiewicz J, Chełkowski D, Jezowska A, Cieślik M, Brzoski M, Smurzyńska A, Dongmin Y, Qiao W. The effect of mixing during laboratory fermentation of maize straw with thermophilic technology. Journal of Ecological Engineering 2018;19(5):93-98. De Longueville B. Community-based geoportals: The next generation? Concepts and methods for the geospatial Web 2.0. Computers, Environment and Urban Systems 2010;4:299-308. Thompson E, Wang Q, Li M. Anaerobic digester systems (ADS) for multiple dairy farms: a GIS analysis for optimal site selection. Energy Policy, 2013;61:114-124. Wandera SM, Qiao W. Algapani DE, Bi S, Dongmin Y, Qi X, Liu Y, Dach J, Dong R. Searching for possibilities to improve the performance of full scale agricultural biogas plants. Renewable Energy 2018;116:720-727. Waszkielis KM, Wronowski R, Chlebus W,

Białobrzewski I, Dach J, Pilarski K, Janczak D.

The effect of temperature, composition and

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Determination of the optimal water intake locations for a salinity gradient energy plant on a stratified river mouth using hydrodynamic modelling

Jacobo M. Salamanca1,*, Oscar Álvarez-Silva2, Aldemar Higgins2, Fernando Tadeo1 1University of Valladolid, Valladolid, Spain; 2Universidad del Norte, Barranquilla, Colombia; *corresponding author email: [email protected] Abstract Stratified river mouths are one of the most promising candidates for exploiting salinity gradient energy, the best locations for water intake are studied. Temperature salinity and water discharge data have been gathered at the Magdalena river mouth to elaborate a hydrodynamic model that represents the salinity profile along the river channel. The hypothetical power production of a pressure retarded osmosis salinity gradient plant has been estimated considering different locations of the saltwater and freshwater provided by the model, and possible locations of such power plant, deducting from it the energy spent on pumping the water streams. Optimal locations have been found by compromising power production and pumping distance. Keywords osmotic energy; pressure retarded osmosis; River mouths; renewable energies; estuary dynamics Introduction In the current context of global warming and increasing worldwide energy demands, the development of renewable energies is essential to reduce carbon emissions to the atmosphere. Sustainable and prosperous societies can only be possible through a major utilization of clean energies.

Aside from the well-established wind and solar energies, there are additional renewable sources of energy whose viability needs to be further explored. One of these is salinity gradient energy (SGE), also known as blue energy or osmotic energy. SGE technologies are based on the chemical potential difference found between water sources with different salinity. The purpose is to transform this potential energy into electricity. In order to do this, several strategies can be followed. The most studied technologies are reverse electrodialysis (RED), which uses a configuration similar to galvanic and fuel cells to generate electricity from the salinity gradient, and pressure-retarded osmosis (PRO), which pursues to convert the salinity gradient into hydraulic work, with the help of a semipermeable membrane. One of

the main advantages of these relatively young technologies is that the energy produced could be available on demand and invariably throughout the day or the seasons, unlike solar and wind energy, which are strongly time and seasonally dependent.

Salinity gradients are found naturally at river mouths, although not every river mouth is suitable for a SGE facility (Álvarez-Silva, 2016). A central requirement is that the river and seawater are available at a short distance, in order to reduce the energy requirements for water transport. The best candidates are stratified river mouths, where salinity gradients can be found in the vertical direction due to a seawater intrusion close to the bottom in the estuarine zone. producing a two layered flow with different densities that will remain unmixed in regions where the tidal range is small (less than 2 m).

The best place for locating the freshwater and saltwater intakes would be in the area of highest stratification of the estuary; at these places, the feed water could be taken close to the surface while the draw water would be taken at a nearby coordinate but closer to the bottom. This configuration would minimize the distance between both intake




96

points and, therefore, the required transport energy However, it is not straightforward to stablish the location in this zone of maximum stratification for a preliminary design of a SGE power plant. It is at this point when a hydrodynamic model of the river mouth is useful.

This work takes the Magdalena river mouth in Colombia as case study, which is the river with the biggest discharge in the Caribbean region and one of the top-ten river mouths with the highest SGE potential worldwide (Álvarez-Silva, 2014). The estuary of Magdalena River is highly stratified and presents salt wedge intrusion into the river channel during low freshwater discharges and a migration of the stratification towards the sea during high discharges has been reported (Restrepo, 2018). Experimental data has been acquired at different locations and depths through the length of the river channel, together with comprehensive information of river flow rates and climatic conditions, and is used to elaborate a model that is able to estimate the salinity structure of the river mouth. The model was used to predict the salinity along the estuary, and this data allowed assessing the potential power production of a hypothetical PRO plant fed from these sources of water. Methods This section describes first the hydrodynamic model implemented for the Magdalena River river mouth. Afterwards, guidelines for calculating the power produced at the hypothetical osmotic plant are established, and the pumping costs associated with it are estimated.

Hydrodynamic model In order to analyse the thermohaline field in the Magdalena river estuary, the numeric model MOHID was employed, based on discretization by finite volumes approximation. A configuration nested on two levels was selected. On the first level the fluid was assumed to be barotropic and considering tidal and daily-average flowrates, with a mesh of

x=y=160 m. On a more detailed second

level, the fluid was treated as baroclinic, a

x=y=80 m mesh and vertical discretization on 35 layers. Advection was estimated through TDV-Superbee method, vertical turbulence followed GOTM model and Canuto stability function, whereas horizontal turbulence was described by Smagorinsky parametrization (Canuto 2001).

Estimation of the PRO power and pumping In a PRO process, freshwater (feed solution)

and seawater (draw solution) are separated by

a semi-permeable membrane that allows the

water flow from the feed side towards the

draw side. This water flow (expressed per unit

of surface) JW multiplied by the

transmembrane pressure gradient P gives the

power produced WPRO:

WPRO = JW·P (1)

In order to determine the water flux through the membrane, a rigorous mathematic model is necessary. In this work, Touati’s general mass transport model is employed, because it considers concentration polarization on both sides of the membrane (Touati, 2015). The parameters necessary are the membrane water permeability A and salt permeability B, transfer coefficients on feed side 𝒌𝑭 and in draw 𝒌𝑫, the solute resistivity K, and osmotic pressures on each feed and draw side 𝝅𝑫 and 𝝅𝑭, respectively.

𝑱𝑾 = 𝑨 [(𝝅𝑫 + 𝜸)∙exp (−𝑱𝑾

𝒌𝑫) −

−(𝝅𝑭 + 𝜸)exp(𝑱𝑾 · 𝑲) · exp (𝑱𝑾

𝒌𝑭) − ∆𝑷] (2)

Where 𝜸 represents:

𝜸 =𝑩

𝑨(𝟏 +

𝑨∆𝑷

𝑱𝑾) (3)

Osmotic pressures are dependent on the salinity, however, the salinities, and therefore πD and πF, do not remain constant throughout the process, they vary along the membrane, because a material exchange is taking place. To correct this situation, several




97

stages are considered using concentrations at intermediate locations of the membrane (Salamanca 2019).

The salinity values of feed and draw side are taken from the salinity profile obtained with the hydrodynamic model described previously on section 2.1.

The energy required for pumping water from the intake locations to the power plant is estimated using Darcy’s equation, the most important variable being the distance. Pumping and PRO turbine efficiencies have been considered.

Results and discussion The calculations and procedures described previously render the results presented on this section.

Hydrodynamic model Figure 1 shows the mean salinity along the estuary near the surface and at 10 m depth, during the dry season of an average climatic year. The horizontal axis indicates distance in km from the end of the river’s channel, with positive distances upstream of the river and negative distances seaward. In can be seen that near the surface the salinity remains close to zero until the end of the river mouth, where salinity increases rapidly as fresh water mixes with the ocean, reaching ocean salinities about 2 km seaward. On the other hand, at 10 m depth the water conserve oceanic salinities up to 300 m inside the river channel, showing salt wedge intrusion and stratification. Further inside the river, close to the bottom, seawater start mixing until reaching uniform freshwater conditions in the vertical profile about 4 km inside the river.

Figure 1. Salinity profile estimated by the hydrodynamic model for the final stretch of the Magdalena river Power production and pumping costs The calculation method described in subsection 2.2 can be applied to any two sources of water. For instance, for the wet season on a normal year, considering the superficial salinity data as the feed and the data close to the bottom as the draw, several curves can be obtained to represent the different possible outcomes for the power production.

In Figure 2, a location for the feed is selected at 1.8 km, and all possible intake points at all distances and their corresponding salinities are used to calculate the power that a PRO plant would present if water were to be taken from all those locations. Figure 3 shows the pumping energy required for each pair of data selected as in for Figure 2.

Figure 2. Power production dependence with the location of the draw water for a given feed location at 1.8km




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Figure 3. Pumping energy required for draw water taken from different locations

This procedure has been repeated for all locations, in order to find the combination of locations that lead to a better overall efficiency, that is, highest power after deducting pumping costs. A higher power production often implies further distance between intake points, therefore a compromise must be reached to optimize the net power production.

Table 1 presents the best results for both gross and net power and their locations, showing an improvement of 7% on the net power.

Table 1 Comparison between the locations leading to highest power production and highest efficiency (net power)

Highest power Best efficiency

Feed intake (km) 6 0.58

Draw intake (km) -2 0.15

Distance (km) 8 0.43

Feed salinity (g/L) 0.11 0.28

Draw salinity (g/L) 34.8 34.3

Gross power production (kW/m3)

627 610

Pumping (kW/m3) 107 51

Net power (kW/m3) 423 468

Conclusions

A hydrodynamic tridimensional model of a

stratified river mouth has been developed

using experimental and historic data.

Hydrodynamic modelling has been showed

to be an effective way to obtain valuable

information of the salinity structure on a

river mouth. This information is used to

determine the power production of a PRO

plant and its dependency on the possible

water intake locations.

The results show the need for a

compromise between the desired lower

intake distances and higher salinity

gradient, for achieving higher power

production. This is why it is important to

find optimal locations in the planification

and design of a potential power plant. The

analysis proposed here found that the

optimal locations provide 7% higher net

power productivity.

References Álvarez-Silva A., Osorio A.F., Winter C. Practical global salinity gradient energy potential. Renewable and Sustainable Energy Reviews 2016;60:1387-1395. Álvarez-Silva A., Winter C., Osorio A.F. Salinity gradeint energy at river mouths. Environmental Science Journal and Technology Letters. 2014;1:410-415. Canuto V.M., Howard A., Cheng Y., Dubovikov M.S. Ocean Turbulence. Part I: One-point closure model momentum and heat vertical diffusivities. Journal of Physical Oceanography. 2001;31:1413-1426. Restrepo J.C., Ortiz J.C. Pierini J. et al. Freshwater discharge into teh Caribbean Sea fromn the rivers of Northwestern South America (Colombia): Magnitude, variability and recent changes. Journal of Hydrology. 2014;509:266-281. Salamanca J.M., Álvarez-Silva O., Tadeo F. Potential and analysis of an osmotic power plant in the Magdalena River using experimental field-data. Energy. 2019;180:548-555. Touati K., Hänel C., Tadeo F., Schiestel T. Effect

of the feed and draw solution temperatures

on PRO performance: Theoretical and

experimental study. Desalination.

2015;365:182-195.




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Co-gasification of coal and municipal sewage sludge to produce methanol Danijela Urbancl1,*, Marko Agrež2, Jurij Krope1, Darko Goričanec1 1University of Maribor, Faculty of Chemistry and Chemical Engineering, Maribor, Slovenia; 2Energetika Ljubljana d.o.o., Ljubljana, Slovenia;*corresponding author email: [email protected] Abstract Municipal sewage sludge is a renewable resource that can be used to produce synthetic fuels. Simulations regarding the co-gasification of coal and municipal sewage sludge within entrained-flow slagging gasifiers (two 500 MWth) were performed using AspenPlus software. This study presents a comparison between the gasification of coal and the co-gasification of coal and municipal sewage sludge. The percentage of sewage sludge used during the co-gasification process varied between 10% and 30%. Methanol was produced from the synthesis gas in all cases. The comparison was based on net present values. The results showed that co-gasification cases outperformed coal-only case in terms of net present value, while the production of methanol was slightly decreased with the increased percentage of sewage sludge in the co-gasification cases. Keywords gasification; municipal sewage sludge; coal; simulation; methanol production

Introduction The gasification of coal and municipal sewage sludge has already been investigated by some researchers. Co-gasification of mixtures of sewage sludge with two types of coal (bituminous and lignite) were performed in a laboratory-scale fluidised bed reactor, where the influence of the feedstock composition was determined on key parameters of the gasification (Garcia at. al., 2013). The gasification of sewage sludge was investigated within near and super-critical water in a batch reactor and the results showed that the formation of gaseous products could be affected by temperature (Chen at al., 2013). The sewage sludge gasification process was investigated in a bubbling fluidised bed gasifier and they studied the influences of different operating variables on the synthesis gas' properties. The variables studied were the equivalence ratio, steam to biomass ratio, and the temperature (De Andres at. al., 2011).

This paper presents a comparison between coal gasification and the co-gasification of coal and municipal biomass within an entrained-flow gasifier. The percentage of sewage sludge, which was calculated on the basis of LHW (lower heating

value) and used during the simulations, varied from 10% to 30%, resulting in three simulations of the co-gasification case (10%, 20%, and 30%). The comparisons are based on the simulations of gasification and methanol productions. Methanol was chosen because it is a key raw material for the syntheses of many different chemicals and is a global commodity with a large and liquid market. Methanol is used for the production of formaldehyde, acetic acid, MTBE (Methyl tert-butyl ether), propylene, DME (Dimethyl ether) etc. Furthermore, methanol can be used as fuel within internal combustion engines and gasoline can also be produced. Methods Simulation of co-gasification within an entrained flow gasifier was performed using Aspen Plus software. Table 1 states the proximate and ultimate analyses of coal and sewage sludge that were used in the model. Table 1 Properties of coal and sewage sludge

Coal Sewage sludge

Pro

x

imat e

anal

ysis

(%

) Moisture 14.2 60.0

Fixed C 34.7 9.0




100

Volatiles 40.5 20.0

Ash 10.6 11.0 U

ltim

ate

anal

ysis

(%)

Carbon 56.4 52.5

Hydrogen 4.4 6.4

Nitrogen 0.8 9.2

Sulphur 1.2 0.8

Oxygen 12.5 31.1

Heating value (MJ/kg) 23.02 7.16

Met

als

con

ten

t

(mg/

kgd

ry)

Ca 11.9 70.9

Mg 1.1 9.2

Cr 0.1 43.3

Hg ND 1.0

Cd ND 1.1

Pb ND 53.8

Simulation Figure 1 presents a simplified flowsheet of the model, which includes the drying of biomass and coal, gasification, a two-stage Rectisol process with WGS reaction and the production of methanol. It was assumed that coal and biomass would be dried in a mill drier to moisture contents of 1.5%, and 3% respectively. CO2 was assumed as the conveyance-gas for transporting the dried pulverised coal and sewage sludge to the gasifier.

Figure 2. A schematic illustration of methanol production from coal and sewage sludge

A two stage Rectisol process was chosen during this study. In the first stage sulphur compounds were removed from the synthesis gas. A certain percentage of the synthesis gas without sulphur was sent directly

to the methanol synthesis section and the remainder to the WGS section for the production of H2 from CO by the following equation:

2 2 2CO + H O CO + H (1)

The WGS reaction was necessary for

obtaining synthesis gas with a suitable ratio between H2, CO, and CO2 for the production of methanol (Trop at. al, 2014). A two-stage WGS process was used. It was assumed that the concentration of CO would be 4% after the high temperature WGS reactor, and 0.03% after the low temperature WGS reactor.

Economic analysis Economic analysis was based on NPV (Net present value). NPV values were calculated covering a 30 year period with an annual discount rate of 5%, and 8400 working hours per year.

The prices for raw materials, methanol and electricity that were assumed for the estimation of revenues and operating costs are listed in Table 2.

Table 2 Estimated prices

Coal price (TET, 2015) 15 €/MWh

SS price (-20) €/t

Methanol price (Methanex, 2015) 365 €/t

Electricity price (TET, 2015) 54 €/MWh

Carbon tax (Ministry, 2015) 14 €/t

Investment cost was calculated by the

following equation:

0 0/ ( )feC n C S n S (2)

where C is the cost of a process unit, n is the number of equally-sized units, C0 is the cost of a reference unit, S is the capacity of a process unit, S0 is the capacity of a reference process unit, e is the cost scaling exponent for different numbers of equally-sized units, and f is the cost- scaling factor (Martelli, 2009). All the prices of equipment were converted to values in 2017 using CEPCI (Chemical Engineering Plant Cost Index). It was assumed that the same




101

type of dryer would be used in the coal-only case and co-gasification case. Results and discussion The molar flows of the main components in the synthesis gas before the compression in compressor C2 are listed in Table 3.

Table 3 Composition of synthesis gas before the compression in C2

2H

n

[kmol/h]

COn

[kmol/h]

2COn

[koml/h]

2Nn

[kmol/h]

Coal only 3793 1684 179 114

Sludge 10% 3799 1690 179 142

Sludge 20% 3808 1694 180 169

Sludge 30% 3818 1697 180 196

It can be seen that the molar flows of

hydrogen and carbon monoxide slightly increased with the increased percentage of sewage sludge.

On the other hand the molar flow of nitrogen, which is an inert material in the synthesis gas, increased substantially with the increased percentage of sewage sludge. The main reason for this results from the higher nitrogen content in the sewage sludge (9.2wt%) compared to coal (0.8wt%).

It is for this reason that the production of methanol slightly decreased with the increased percentage of sewage sludge used in the process.

Consequently the heating value of the purge gas increased with the increased usage of sewage sludge; therefore more electricity can be produced in the gas turbine, as shown in Figure 2.

Figure 2. Electrical power produced in the gas turbine and triple-stage steam turbine

In all the calculations of net present value, Figure 3, it was assumed that all prices for raw materials and products, and also the annual discount rate would be constant during the 30 year-long period. This assumption was slightly unrealistic but was used for simplicity. It can be seen that the co-gasification cases performed better than the coal-only case. If 30 % sewage sludge were to be used instead of coal the net present value would amount to 2,901M€, after a 30 year period, whilst the coal-only case’s net present value would amount to 1,961M€. This result was expected because the assumed price of sewage sludge was negative. It is also considered as a carbon neutral material; therefore carbon tax was lower in the case of co-gasification.

Conclusions Co-gasification of sewage sludge in entrained-flow slagging gasifiers with pneumatic feeding was presented in this work and compared to a coal to methanol process in terms of net present values.

High moisture content in sewage sludge presents a disadvantage, which results in a higher consumption of steam for the drying of sewage sludge and consequently lower generation of electricity.

However, the major advantages of sewage sludge are its negative price and carbon neutrality. Those advantages outweigh the disadvantages, resulting in the higher net present values of all co-gasification cases.

0

10

20

30

40

50

60

70

80

Coal only Sludge 10% Sludge 20% Sludge 30%

PO

WER

[M

W]

Gas turbine Steam turbine




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It can be concluded that the application of sewage sludge as a resource for partial replacement for coal would present a better route for the synthesis of methanol from renewable resources, which would be economically feasible and environmentally-friendly. References Y. Chen, L. Guo, H. Jin, J. Yin, Y. Lu, and X. Zhang, “An experimental investigation of sewage sludge gasification in near and super-critical water using a batch reactor,” International Journal of Hydrogen Energy, vol. 38, no. 29, pp. 12912–12920, Sep. 2013. J. M. de Andrés, A. Narros, and M. E. Rodríguez, “Air-steam gasification of sewage sludge in a bubbling bed reactor: Effect of alumina as a primary catalyst,” Fuel Processing Technology, vol. 92, no. 3, pp. 433–440, Mar. 2011 G. García, J. Arauzo, A. Gonzalo, J. L. Sánchez, and J. Ábrego, “Influence of feedstock composition in fluidised bed co-gasification of

mixtures of lignite, bituminous coal and sewage sludge,” Chemical Engineering Journal, vol. 222, no. 0, pp. 345–352, Apr. 2013. P. Trop, B. Anicic, and D. Goricanec, “Production of methanol from a mixture of torrefied biomass and coal,” Energy, vol. 77, pp. 125–132, Dec. 2014. E. Martelli, T. Kreutz, and S. Consonni, “Comparison of coal IGCC with and without CO2 capture and storage: Shell gasification with standard vs. partial water quench,” Energy Procedia, vol. 1, no. 1, pp. 607–614, Feb. 2009. “Proizvodni proces - Termoelektrarna Trbovlje.” [Online]. Available: http://www.tet.si/si/elektricna-energija/proizvodni-proces/. [Accessed: 14-Feb-2015]. “Pricing | Methanex Corporation.” [Online]. Available: https://www.methanex.com/our-business/pricing. [Accessed: 01-Jul-2015]. Ministry of Finance, “Environmental Taxes,”

May-2015.




103

Production of biogas in a dry anaerobic digestion reactor of residues generated in the processing of sheep and alpaca wool

Salamanca-Valdivia, M1; Cardenas-Herrera, L2; Barreda-Del-Carpio, J1,*; Munive-Talavera, C1; Garate-Manrique, R3; Moscoso-Apaza, G3; Villanueva-Salas, J1 1Universidad Catolica de Santa Maria, Facultad de Ciencias Farmaceuticas, Bioquimicas y Biotecnologicas, Arequipa, Peru; 2Universidad Nacional de San Agustin, Facultad de Medicina, Arequipa, Peru; 3Instituto de Investigacion y Desarrollo para el Sur, Arequipa, Peru; *corresponding author email: [email protected] Abstract The aim of the current research was the isolation, characterization and identification of native microbial strains from waste generated in the processing of sheep wool and alpaca fiber, for the production of biogas inside a dry anaerobic digestion (DAD) reactor in order to degrade solid waste coming from the textile industry. In total 52 bacterial strains and 15 fungal strains were isolated in anaerobic conditions from samples taken from solid waste produced in the processing of alpaca fiber and sheep wool by the Inca Tops textile company. Both the biogas composition and production were evaluated in 3 DAD reactors with different inocula: bacteria, fungi and microbial consortia; with the consortium inoculated reactor having the best production rate and best biogas attributes obtaining 33.38 %, 6 %, 1.44 % and 0.89 ppm methane, carbon dioxide, oxygen, and hydrogen sulfide respectively. Keywords solid waste; dry anaerobic digestion; reactor; fungal; biogas Introduction Solid waste treatment with anaerobic digestion can solve the environmental issues associated to their production, as well as provide biogas as renewable energy for a sustainable development (Chattopadhyay, 2009).

Industry-wise, the most common process is biogas production from high water content waste; however, the use of municipal and industrial waste as well as solid waste coming from agricultural activities, is rising in importance. Solid waste usually has solid content between 15% to 50%, thus requiring great quantities of water when using traditional treatments. For this reason, using dry anaerobic digestion (DAD) technology for waste treatment and biogas production is a better alternative that allows disposing of low water content waste (Renewables, 2017).

Biogas production with the use of DAD technology has progressed significantly through the years and is now focusing in the

usage of easy-access raw material for a better output. In this respect and because of the availability and abundance of some raw materials, biogas production has great potential when using agricultural waste, cattle waste, municipal waste, food waste, aquatic biomass, keratin residues and lignocellulosic raw materials (Patinvoh, 2017).

The treatment of solid waste through anaerobic digestion can solve the environmental problems caused by these ones and also supply biogas as renewable energy for sustainable development. In addition, the biogas produced for the generation of energy and the residue of the digestion can be used as a biofertilizer.

In industry, the most common process is the production of biogas from waste with high water content; however, using DAD technology is a better option for managing waste streams with low moisture content.

Main body

mailto:[email protected]




104

Anaerobic digestion Anaerobic digestion results in biogas production, a natural process that involves the biological conversion of organic Carbon into CO2 and CH4. Anaerobic digestion is an incredible, selective, natural process that allows to reduce a great variety of organic substrates into methane, a very useful molecule. This process has been observed in nature in wetlands, paddy fields and inside several animals’ intestines as well (Chynoweth, 1996) Microbiology of the anaerobic processes. Understanding of the complex interactions between the microorganisms involved in DAD is key to improve the process management. Depending on the substrate consumed, microorganisms can be classified into autotrophic and heterotrophic. Heterotrophic microorganisms use organic matter as an energy and carbon source in order to synthesize new microorganisms; in contrast, autotrophic ones oxidize inorganic compounds to obtain energy while using CO2 as a carbon source (Del Real, 2007). Methods Isolation of native microorganisms from waste generated in the processing of sheep wool and alpaca fiber. Two culture media were prepared: blood agar for bacteria and Sabouraud agar for fungi. These were later sterilized in autoclave for 15 minutes at 120°C and 1.5 atm, to be then distributed in 20 mL plates and, after having solidified and being sealed, be stored in an incubator for 24 hours in order to verify the environment’s safety.

Thioglycollate broth was prepared and poured in 20mL tubes for bacterial isolation. The medium was sterilized in autoclave for 15 minutes at 120°C and 1.5 atm and then stored in an incubator for 24 hours in order to verify the environment’s safety. Finally, the previously treated samples were cultured in

thioglycollate broth and stored in an incubator for 72 hours.

A small portion of the sample was taken with a Kolle handle and cultured by streaking in Petri dishes containing blood agar. Lastly, the plates were preserved in an anaerobic jar and stored in an incubation chamber at 37°C.

Sabouraud agar was prepared to isolate fungi. A small sample was taken and cultured to be later preserved in an anaerobic jar and stored in an incubation chamber at 37°C.

Succesive culturing was performed from the main plates into new blood agar and Sabouraud agar plates to obtain pure strains.

3.2. Characterization and molecular identification of selected bacterial and fungal species with gas producing capacity.

DNA from native strains was isolated and then amplified through Polymerase Chain Reaction (PCR) technology. The PCR product was separated in an agarose gel (1.5%), and the band corresponding to the RNAr 16s and ITS genes was cut for further purification.

RNAr 16s gene sequences from the native strains obtained by sequencing were individually analized and compared with sequences stored in the GenBank database using the BLAST algorithm (www.ncbi.nlm.nih.gov/BLAST). Then, phylogenetic trees were built to determine genetic distances and similarity percentage. Moreover, multiple alignment and phylogeny tests were performed with the CLUSTAL Omega program.

Production and gas composition evaluation of different inocula using a dry anaerobic digestion reactor. In order for the reactors to work 5 Kg of textile solid waste were first placed. Solid waste was previously hydrated with the textile company’s residual water to improve recirculation. The first reactor was then inoculated with bacteria while the second reactor was inoculated with fungi, and the third reactor with a microbial consortium. Finally, the reactors were hermetically closed creating an anaerobic environment ideal to the process

http://www.ncbi.nlm.nih.gov/BLAST




105

development. The working time for the reactors was 60 days of which the first 15 there was no influent recirculation (adaptation phase), and the remaining 45 days the system worked with influent recirculation.

The gas production ratio of each reactor was determined along with the gas composition using the gas meter unit MultitecR 540 that measures CH4, CO2, H2S and O2.

Results The strains isolated from the textile solid waste have, on top of being anaerobic, the capacity to produce biogas. For this reason Sabouraud agar and thioglycollate broth with agar are used in tubes. These, being solid media, allow the detection of biogas by the media rupture or displacement inside the test tube.

Taking this into account each of the isolated strains was evaluated. The bacterial strains were cultured in thioglycollate medium and the fungal strains were cultured in Sabouraud medium, the results showing that only 3 bacterial strains and 3 fungal strains have the ability to produce biogas as shown in Table 1.

Table 1 Bacterial and fungal species with gas production capacity.

Bacteria Fungal

Pseudomona auruginosa Fusarium sp

Proteus vulgaris Fusarium oxyporum

Alcaligenes sp Monascus ruber

Biogas composition was evaluated in 3

DAD reactors with different inocula: bacterial inoculum for Reactor 1, fungal inoculum for Reactor 2, and a fungal and bacterial consortium inoculum for Reactor 3; as shown in Figure 1.

Figure 1. Gas composition comparison.

Finally fungal and bacterial consortium inoculum for Reactor 3; as shown in Figure 2, has the best biogas production.

Figure 2. Gas production comparison

Discussions A high percentage of methane can be observed, however it is not between the reported values of 40 to 70 % in biogas (Porpatham, 2008). The low percentages of carbon dioxide are almost in the range for values obtained after the application of different treatments for removing biogas. These values are between 0-4% (Souza , 2013) (Barik, 2013) and therefore a biogas removing treatment is not necessary. For the O2 values a mean percentage of 1.44% is reported. It is important to highlight the low levels of hydrogen sulfide (2ppm) since the reported values are in the range of 10 000 to 20 000ppm (Ryan, 2014). This is a very relevant characteristic since sulfuric acid is considered a contaminant in biogas production and requires treatment in order to eliminate it. Conclusions

0,00%

10,00%

20,00%

30,00%

40,00%

Methane Carbondioxide

Oxygen Hydrogensulfide

Biogas Composition: Fungal and bacterial consortium




106

In total 52 bacterial strains and 15 fungal

strains were isolated from textile solid waste

produced by the Inca Tops company.

Three fungal strains and three bacterial

strains were selected due to their gas

production capacity.

Selected strains with gas production capacity

were characterized and molecularly

identified as Pseudomona auruginosa,

Proteus vulgaris, Alcaligene ssp., Fusarium

sp., Fusarium oxyporumy, and Monascus

ruber.

Gas production and gas composition were

evaluated comparing 3 different inocula:

bacteria, fungi and a consortium. The reactor

inoculated with the bacterial-fungal

consortium has a good gas production ratio,

and a good gas composition.

Acknowledgments This research was supported by the project PITEI-3-P-343-105-15 Innovate Peru. References Chynoweth DP. Environmental impact of biomethanogenesis. Environ Monit Assess 1996;42(1):3-18.

Del Real, J. Evaluación y modelado de la cinética de depuración anaerobia de vinazas de la industria alcoholera. [México]; 2007. Chattopadhyay S, Dutta A, Ray S. Municipal solid waste management in Kolkata, India – A review. Waste Management. 2009;29(4):1449-58. Renewables 2017: Global Status Report. [Internet]. 2017. Available at: https://apps.uqo.ca/LoginSigparb/LoginPourRessources.aspx?url=http://www.deslibris.ca/ID/10091341 Patinvoh R.J., Osadolor O.A., Chandolias K., Sárvári Horváth I., Taherzadeh MJ. Innovative pretreatment strategies for biogas production. Bioresource Technologye 2017;224:13-24. Porpatham E, Ramesh A, Nagalingam B. Investigation on the effect of concentration of methane in biogas when used as a fuel for a spark ignition engine. Fuel. e 2008;87(8):1651-9. Souza J, Schaeffer L. Sistema de compresión de biogás y biometano. Información tecnológica. 2013;24(6):03-8. Barik D SS, Murugan S. Biogas production and storage for fueling internal combustion engines. 2013. Ryan KJ. Sherris medical microbiology

[Internet]. Sexta edicion. 2014, p 617-627

Available at:

http://accessmedicine.mhmedical.com/book.a

spx?bookid=2268

https://apps.uqo.ca/LoginSigparb/LoginPourRessources.aspx?url=http://www.deslibris.ca/ID/10091341






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The impact of biowaste pasteurization on the methane yield in the fermentation process

Jakub Pulka1,*, Jakub Mazurkiewicz1, Wojciech Czekała1, Patrycja Pochwatka2, Marta Cieślik3, Filip Tarkowski1, Jacek Dach1 1Poznan University of Life Sciences, Institute of Biosystems Engineering, Poznan, Poland; 2University of Life Sciences in Lublin, Department of Environmental Engineering and Geodesy, Lublin, Poland; 3Poznan University of Life Sciences, Faculty of Food Science and Nutrition, Poznan, Poland *corresponding author email: [email protected] Abstract Analyzing Polish statistical data on the amount of generated municipal waste and its morphological composition, it can be estimated that the potential stream of bio-waste will be approximately 3.5 million Mg per year. Kitchen waste stream can consist animal by-product, hence pasteurization is required as a fermentation pretreatment. This potentially high content of proteins creates a problem with increased ammonia nitrogen level which can be strong inhibition factor sharply decreasing methane production. That is why the preliminary tests of urban biowaste fermentation are essential for creating its fermentation technology for real-scale investments. This paper presents initial study on pasteurization influence on methane, biogas yield, chemical oxygen demand (COD) and ammonium nitrogen concentration in waste eluates. Biowaste pasteurization had positive influence on fermentation process causing a 3% increase in cumulated methane production, and a 1% increase in biogas yield. COD and ammonium nitrogen concentration in eluate after pasteurization increased 44% and 86% respectively. Keywords kitchen and urban waste; biogas production; ammonia content Introduction According to Regulation of the Minister of Environment of December 29 2016, on the detailed method of selective collection of selected waste fractions, selective collection of biowaste is mandatory. Biowaste stream con consists of both kitchen waste and biodegradable waste from gardens and parks. Kitchen waste and “green waste” can be selected separately or collectively. Due to the organic origin of this waste stream fermentation and composting are main treatment methods according to legislators (The Act of 14 December 2012 on waste).

Kitchen waste stream can consist animal by-product, hence pasteurization is required as a fermentation pretreatment (Regulation (EC) No 1069/2009 of the European Parliament and of the Council of 21 October 2009). Based on the general

assumption, several scientists have tried to determine how this type of pre-treatment affects the fermentation process, methane production, and biogas yield. This is not a simple task, because the economic and energetic output strongly depends on the biodegradability of organic matter in bio-waste and the purity and freshness of the mixture.

In the case of energy production, anaerobic digestion combined with biogas combustion in mixed cycle installations for electricity and heat is not the most efficient method of (Chartier et al., 1996). Additionally, the pasteurization is a way to solve the hygiene problem but is associated with high energy demand (Liu et al., 2018).

Nevertheless, this form of thermal hygienisation is often carried out before the fermentation process. It is a kind of pre-treatment with an additional goal, which is to increase methane production (Liu et al., 2018).




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The cited publication shows results from different countries and on different waste, i.e. agricultural waste (AW) municipal solid wastes (MSW), animal by-products (ABP), waste activated sludge (WAS).

In one of his works, Liu (Liu et al., 2019) indicates sources according to which the initial heat treatment increases methane production up to 50% in the case of secondary sewage sludge and food processing waste subjected to pre-treatment at 70°C, the particularly beneficial effect relates to the potential of bio-methane or kinetics of methane production. The same scientists (Liu et al., 2019) note at the same time that in some cases such a significant impact on mixed pork waste, animal droppings and the mixture of MSW and ABP was not observed. These contradictory results can be explained by the physicochemical reactions of substrates during thermal pretreatment, including particle size reduction, formation of complex compounds and inhibition processes, such as the accumulation of NH3 derived from proteins, volatile fatty acids (VFA) degraded from long-chain fatty acids (LCFA) and competition of H2/sulfate-consuming bacteria with methanogenic bacteria (Liu et al. 2019). Other researchers (Ware et al., 2015) argue how specific methane yields (SMY) and the overall bioavailability of offal taken from slaughter cattle, pigs and chicken changed after pasteurization - obtaining high SMY, i.e. 465-650 mLCH4/gVS, however, without a statistically significant increase in methane production compared to the sample without heat treatment. However, they noticed that the kinetics of biogas transformation processes highlighted the increased bioavailability of organic compounds due to pasteurization.

It turns out that in some cases appropriate addition of green waste favorably affects the entire technological process (and economically associated with the need to separate green waste from kitchen waste), although the energy potential of this waste is much lower than kitchen waste. The addition of easily degradable substrates, such as short-lived herbaceous plants, will improve the availability of carbon sources for the metabolism of methane (Tayyab et al., 2019; Lovarelli et al., 2019). In addition, increasing the abundance of anaerobic bacteria will

increase the capacity and efficiency of processes. These techniques have the potential to solve contemporary problems of successful operation and are an economically viable option for the fermentation process. This is particularly important when considering the management of different waste streams.

Taking that into account preliminary tests of urban biowaste fermentation were conducted, and the influence of pasteurization on the fermentation process was investigated. Materials and methods Biowaste used in this research consists of 40 % green waste, 50 % food waste, and 10 % meat waste. Waste fraction originated from Municipal Solid Waste Installation. Waste properties Waste properties were characterized by 35.76% of dry mass and 73.69% organic dry mass content..

Pasteurization was performed in enclosed reactor in 70°C for 1h. Before pasteurization material were shredded ensuring particle size below 12 mm (Regulation (EC) No 1069/2009 of the European Parliament and of the Council of 21 October 2009) Methane fermentation was conducted in 37° in batch reactor using DIN 38 414/S8 standard. Material analysis were conducted according to:

Water extracts were prepared using

PN-Z-15009 standard.

Chemical oxygen demand was

conducted on COD Vario Tube Test HR

Moisture content was conducted using

PN-EN 14346:2011

Loss on ignition was conducted using

PN-EN 15169:2011

Results and discussion Biowaste after pasteurization cumulative methane production amounted for 104.88 m3∙Mg-1 which is a 3 % increase compared to biowaste without pasteurization (Table 1). Whereas cumulated biogas production increased by only 1 % after pasteurization. This is related to a 2 % increase in methane content for samples after pasteurization.

Table 1




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Methane content, cumulated methane and cumulated biogas in fresh matter.

Sample CH4 [%]

Cum. CH4,

[m3·Mg-1]

Cum. biogas,

[m3·Mg-1]

Biowaste 58.59±2.00

102.04±0.81 174.17±0.82

Biowaste + Pasteurization

59.82±1.65

104.88±0.67 175.32±0.91

A similar distribution is visible when

analyzing biogas and methane yield in dry matter, and in volatile solids (Table 2 and 3). Compeering methane yield for biowaste sample in relation to a fresh matter obtained results were much higher than fruits (Czekała et al., 2016), whey (Kozłowski et al., 2019), and similar to maze straw silage (Cieślik et al., 2016).

Table 3 Methane content, cumulated methane and cumulated biogas in dry matter.

Sample CH4 [%]

Cum. CH4,

[m3·Mg-1]

Cum. biogas,

[m3·Mg-1]


285.33±2.28 487.02±2.28


59.82±1.65

293.23±1.87 490.22±2.56

On the other hand methane yield of

maze straw silage and whey in relation to total solids and volatile solids was significantly lower than biowaste, whereas fruits yielded similar results (Czekała et al., 2016; Kozłowski et al., 2019; Cieślik et al., 2016). It’s worth pointing out that methane and biogas yield increase was significantly lower than 50 to 70 % described in (Liu et al., 2019).

Table 3 Methane content, cumulated methane and cumulated biogas in Volatile solids.

Sample CH4 [%]

Cum. CH4,

[m3·Mg-1]

Cum. biogas,

[m3·Mg-1]


387.22±3.09 660.93±3.09


59.82±1.65

397.94±2.53 665.28±3.47

From literature data (Liu et al., 2018), it can be concluded that hygienisation at the EU level requires more caution than those proposed by its own members and other

countries in the world. In additions, some researchers questioned this consideration in terms of efficacy and accuracy of the pathogen dynamics of the treatment (Goden et al., 2017). Worldwide legislation on the hygienisation of bio-waste focuses on the gentle heat treatment before the fermentation process. The EU submit the strictest sanitary rules (70° C for 1 hour) compared with other countries. This thermal hygienisation accounts for ca. 6 - 25% of total energy production in European biogas installations (Liu et al., 2019).

Table 4 Chemical oxygen demand and ammonium content in eluted from biowaste.

Sample COD,

g·dm-3 NH4,

mg·dm-3

Biowaste 62.3 412


89.6 766

Preliminary analysis of pasteurization

influence on hydrolyzation regarded as COD and NH4 are shown in Table 4. It’s worth mentioning that pasteurization increased COD content in eluate by 44 % and NH4 content 86%. It’s worth noticing that faster hydrolyzation should increase fermentation kinetics and biogas yield. Therefore this phenomenon should be truthfully investigated on both batch and continuous fermentation in order to fully investigate the role of hydrolyzation as a way to increase waste fermentation potential. Conclusions

• Biowaste after pasteurization

exhibited slight increase in cumulative

methane yield in relations to f.m., d.m.,

v.s.

• Pasteurization increased significantly

COD and ammonia content in eluate.

• Influence of pasteurization should be

thoroughly investigated

Acknowledgments The work has been presented at the 4th Renewable Energy Sources - Research and




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Business (RESRB) conference held on 8-9 July 2019 in Wrocław (Poland). This study was performed as part of the statutory research no. 506.105.06.00 in the discipline of Environmental Engineering, Mining and Energetics, entitled "Energetic use of waste as a method of improving the environment". References

Regulation of the Minister of Environment of

December 29, 2016 on the detailed method of

selective collection of selected waste fractions.

The Act of 14 December 2012 on waste Regulation (EC) No 1069/2009 of the European Parliment and of the Council of 21 October 2009. Chartier P, Ferrero GL, Henius UM, Hultberg S, Sachau J, Wiinblad M. Biomass for Energy and the Environment. 1996. Liu X, Lendormi T, Lanoisellé JL. A Review of Hygienization Technology of Biowastes for Anaerobic Digestion: Effect on Pathogen Inactivation and Methane Production. Chemical Engineering Transactions 2018; 70:529-534. Liu X, Lendormi T, Lanoisellé JL. Overview of hygienization pretreatment for pasteurization and methane potential enhancement of biowaste: Challenges, state of the art and alternative technologies. Journal of Cleaner Production 2019;236:117525. Goden JJ, Wery N, Bernet N. Pathogen decay or growth in anaerobic digestion: a question with no possible answer? Elements of

understanding for non-microbiologists, Presented at the 15th IWA International Conference on Anaerobic Digestion (Poster No D2), 2017, Beijing, China Ware A, Power N. What is the effect of mandatory pasteurisation on the biogas transformation of solid slaughterhouse wastes? Waste management 2015;48:503-512. Tayyab A, Ahmad Z, Mahmood T, Khalid A, Qadeer S, Mahmood S, Andleeb S, Anjum, M. Anaerobic co-digestion of catering food waste utilizing Parthenium hysterophorus as co-substrate for biogas production. Biomass and Bioenergy 2019;124:74-82. Lovarelli D, Falcone G, Orsi L, Bacenetti, J. Agricultural small anaerobic digestion plants: Combining economic and environmental assessment. Biomass and Bioenergy 2019; 128:105302. Cieślik M, Dach J, Lewicki A, Smurzyńska A, Janczak D, Pawlicka-Kaczorowska J, Boniecki P, Cyplika P, Czekała W, Jóźwiakowski K. Methane fermentation of the maize straw silage under meso- and thermophilic conditions, Energy 2016, 115(2):1495-1502. Kozłowski K, Pietrzykowski M, Czekała W, Dach J, Kowalczyk-Juśko A, Józwiakowski K, Brzoski M. Energetic and economic analysis of biogas plant with using the dairy industry waste. Energy 2019;183:1023-1031. Czekała W, Smurzyńska A, Cieślik M, Boniecki

P, Kozłowski K. Biogas efficiency of selected

fresh fruit covered by the Russian embargo,

Energy and clean technologies conference

proceedings, 2-5 November, 2016 Extended

Scientific Sessions Vienna, Austria.




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Zero Waste Egg Production: modeling of valorization of poultry manure Andrzej Białowiec1,3*, Ewa Syguła1, Piotr Manczarski2, Jacek A. Koziel3 1Faculty of Life Sciences and Technology, Institute of Agricultural Engineering, Wrocław University of Environmental and Life Sciences, Wrocław, Poland; 2Warsaw University of Technology, Warszawa, Poland; 3Iowa State University, Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA 50011, USA; *corresponding author email: [email protected] Abstract Egg and poultry industry need continued efforts improving sustainability and effective energy management. Proposed research addresses both specific areas. Specific research questions arise: What monetary profits and operational cost reductions could be expected from valorizing manure as a source of marketable renewable energy? What environmental benefits could be expected from valorizing manure? We have developed a techno-economic model for comprehensive valorization of manure as a source of marketable and on-farm energy. We evaluated the reduction of environmental footprint associated with the introduction of comprehensive on-farm valorization of poultry manure. Executed modeling indicated that due to manure torrefaction the valorized biochar may be produced and used as a source of energy for poultry farm. Zero waste and circular economy principles may be achieved when the poultry manure torrefaction, with the recirculation of biochar as a solid fuel is applied. Keywords torrefaction; poultry manure; zero waste; egg production; energy recovery Introduction

Poultry manure (PM) production is one of the main sectors in the food industry. The characteristics of poultry production have a growing tendency. Poland is a leader in the production of poultry in Europe (Utnik-Banaś, Krawczyk 2016). Poultry farms in Poland produce around 2,5 million tons of chicken manure per year (Gornowicz et al. 2017). The difficulty is the usage of chicken manure for agricultural purposes. Farms with 100 000 chickens require 350-600 ha of land depending on the concentration of N in the droppings Sobczak (2008). The waste from the poultry industry is a natural by-product. Controlling of it is challenging due to the variable properties of the chicken manure. An important element to eliminate in PM are so called - pathogens - such as: Staphylococcus, Clostridium, yeast and antibiotics (Sánchez-García et al. 2015). The most popular way of managing poultry manure is composting. However, problem become with NH3 and odors emission

(Mondini et al. 1996). The costs of poultry manure composting escalate the costs of buying already prepared agricultural fertilizer (Bernal et al. 2009). This is due to the composting process control because PM is a complex substrate for biological processes. PM is characterized by high humidity and high NH3 concentration as well as a low C/N ratio (Ihnat, Fernandes 1996). The process of fermentation of chicken manure allows to obtain a high biogas production (250 to 450 m3∙Mg d.o.m.-1), and 60% (volume) of methane content in biogas (Fugol, Prask 2011). The poultry manure creates operational problems in biogas factories. This is related to an unfavourable C/N ratio of 2:1 to 14:1 and a high concentration of ammonium nitrogen. The problem with waste from poultry production also occurs because of antibiotics which are not completely metabolized by animals. However, biological processes are not able to properly stabilize the PM itself. It is necessary to add components supporting the process (Wei et al. 2014). The complicated process of monitoring biological methods of PM management and high financial




112

costs forced to look for other methods of utilization. The torrefaction process could be an alternative. During this practice chicken manure is roasted. Main body Proposed model research addresses both sustainability and energy recovery during egg production leading to the achievement of zero waste and circular economy approach (Figure 1). Specific research questions arise: What monetary profits and operational cost reductions could be expected from valorizing manure as a source of marketable renewable energy? What environmental benefits could be expected from valorizing manure? Methods Preparation of material for testing The poultry manure sample, at the begging, was dried for 24 hours in a WAMED laboratory dryer, model KBC-65W (Warsaw, Poland) at 105 °C. Subsequently, the dry PM sample was pulverized on a mill through a 0.1 mm sieve (grinder model: TESTCHEM laboratory mill, model LMN-100 (Pszów, Poland)). Unprocessed waste from poultry farms and biochar produced from PM were characterized by the determination of humidity, ash content, calorific value.

The PM torrefaction and biochar generation

The torrefaction of poultry manure was carried out in accordance with the procedure described by Syguła et. (2019) in a muffle furnace (Snol 8.1/1100, Utena, Lithuania). The carbon dioxide was used as an inert gas with a flow of 10 dm3∙h-1. The process was carried out under 240 °C and a duration of 45 minutes.

Economic analysis

It was assumed that the capacity of the installation should allow to process 200 Mg of wet manure per day, which corresponds to 75000 Mg of wet manure per year. It was also assumed that the manure is produced 365 days a year. In the economic analysis, the prices of individual fuels were assumed: price per tonne

of biochar 50 PLN (12 EUR·Mg-1) and pellet made of straw biomass 350 PLN·Mg-1 (84 EUR·Mg-1). Below are three tested variants of economic analysis: Variant 1 - with extensive technical infrastructure related to heat recuperation from the torrefaction process, condensation of water vapor. In the variant, it is anticipated that all torgas and a part of the biochar will be used to supply the boiler. Variant 2 - recuperation is provided only for the recovery of heat from the torrefaction process. In the variant, it is anticipated that all torgas and a part of the biochar will be used to supply the boiler. Variant 3 - recuperation is provided only for the recovery of heat from the torrefaction process. The variant foresees that all torgas and the remaining heat demand will be covered with the burning of straw pellets in the boiler.

Results Table 1 presents the initial properties of the poultry manure and the biochar. Table 1 The properties of raw PM and biochar.

Detailed results regarding economic analysis are presented in table 2. Table 2 Mass and economical balance of the torrefaction process depending on the adopted technological configuration.

Parameter Unit Poultry manure

Biochar from poultry manure

Moisture % 64.0 1.7

HHV MJ∙kg d.m.-1

13.295 13.428

Ash % d.m. 29.6 34.8




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Conclusions The process of poultry manure torrefaction results in a hydrophobic product, with calorific value of 13.5 MJ/kg, which makes the biochar a relatively suitable product for energy generation purposes. Due to the source of the biomass, which is poultry manure, the biochar is characterized by high ash content. Application of torrefaction for poultry manure treatment may be profitable when efficient recuperation systems and biochar recirculation for covering energy demand is used.

The increase of the heat recuperation efficiency decreases the demand for biochar for recirculation and increases profits. Using a low efficient system with covering the energy demand from external sources makes that poultry manure torrefaction is not profitable. References 1. Bernal M.P., Alburquerque J.A., Moral R.

Composting of animal manures and

chemical criteria for compost maturity

assessment. A review. Bioresource

Technology 2009;100;5444–5453.

2. Fugol M., Prask, H.. Porównanie uzysku

biogazu z trzech rodzajów kiszonek: z

kukurydzy, lucerny i trawy. Inżynieria

Rolnicza 2011;9(134); 31-38.

3. Gornowicz E., Pietrzak M., Stanisławski D.,

Steppa R., Lewko L., Kryza A.

Charakterystyka jakości mięsa kurcząt

rzeźnych odchowywanych ekologicznie i

intensywnie. Roczniki Naukowe Polskiego

Towarzystwa Zootechnicznego 2017; 34.

4. Ihnat M., Fernandes L. Trace elemental

characterization of composted poultry

manure. Bioresource Technology

1996;57;143-156.

5. Mondini C., Chiumenti R., da Borso F., Leita

L., De Nobili M. Changes during processing

in the organic matter of composted and air-

dried poultry manure. Bioresource

Technology 1996;55;243-249.

6. Sánchez-García M., Alburquerque J.A.,

Sánchez-Monedero M.A., Roig A., Cayuela

M.L. Biochar accelerates organic matter

degradation and enhances N mineralisation

during composting of poultry manure

without a relevant impact on gas emissions.

Bioresource Technology 2015;192; 272–

279.

7. Syguła, E.; A. Koziel, J.; Białowiec, A. Waste

to Carbon: Preliminary Research on

Mushroom Spent Compost Torrefaction.

Preprints 2019.

8. Utnik – Banaś K., Krawczyk J. Produkcja

drobiarska w aspekcie podstawowych

założeń biogospodarki. Stowarzyszenie

ekonomistów rolnictwa i agrobiznesu 2016;

tom XVIII; zeszyt 2.

9. Wei L., Shutao W., Jin Z., Tong X. Biochar

influences the microbial community

structure during tomato stalk composting

with chicken manure. Bioresource

Technology 2014;154; 148–154.

Parameter Unit Variant

1 Variant

2 Variant

3

Feedstock mass

Mg∙h-1 9.125 9.125 9,125

Mg∙y-1 75 000 75 000 75 000

Mass of biochar as fertilizer

Mg∙h-1 2.173 1.115 2.691

Mg∙y-1 17 382 8 924 21 524

Mass of biochar for

recirculation

Mg∙h-1 0.518 1.575 0

Mg∙y-1 4 142 12 600 0

Share of biochar for

recirculation % 19.2 58.5 0.0

Mass of pellet to be purchased

Mg∙h-1 0 0 1.513

Mg∙y-1 0 0 12 102

Mass of wastewater

Mg∙h-1 4.995 0.790 0.790

Mg∙y-1 39 961 6 317 6 317

Mass of ash Mg∙h-1 0.181 0.550 0.076

Mg∙y-1 1 446 4398 605

Costs of pellets

purchasing

EUR∙ year-1 0 0

1 008 500

Income from biochar selling

UER∙ year-1

206 928

106 238

256 238

Revenue EUR∙ year-1

206 928

106 238

-752 262




114

Figure 1. Zero waste egg production concept by application of poultry manure torrefaction and incineration of produced

biochar




115

Alternative designs on liquid-flow window technology

Tin-Tai Chow1,*, Wenjie Liu1 1City University of Hong Kong, Hong Kong SAR, China; *corresponding author email: [email protected] Abstract Liquid-flow window is a novel multi-glazing design concept to deal with the thermal weakness of building glazed facade. A flowing liquid layer within the cavity of a multi-pane window is able to reduce the space air-conditioning load and at the same time, to reduce the services hot water energy consumption. Such a liquid circulation can be on either mechanical-flow or buoyant-flow basis. In recent years, different system designs and applications have been suggested and with their energy-saving potential evaluated. This paper firstly discusses the current design and application trends. Then a novel alternative design - the liquid-bath type - is introduced. This new approach carries the advantage of the buoyant flow concept in better water pressure control, but with substantial improvement in heat removal capability and simplified window frame structure. Keywords solar energy; window glazing; building-integrated thermal system; water heating; zero-energy building Introduction Urbanization in modern cities leads to the increase in suspended particulates in the atmosphere, and thus a decrease in visibility. At the same time, anthropogenic heat like those rejected from air-cooling plants leads to urban heat island effect, resulting in higher temperature at the city centre than the suburb areas. The effect is intensified by the daytime heat absorption by the building materials, which is later on released at night. One solution for these global problems is to go for a low-carbon urban environment with the introduction of green buildings [Floyd and Bilka 2012], which carry practicing sustainable measures like: • Optimized use of energy, water, and other resources; • Reducing waste and pollution; • Improved occupant/neighbourhood health, comfort, safety, and productivity; and • Planning throughout the life-cycle of a building, from siting to design, construction, operation, maintenance, renovation and demolition. Development trend in window glazing

Extensively-glazed building is a world-wide architectural trend. The advantages come from its natural brightness, transparency, modernity, and indoor-outdoor interaction. Nevertheless, the disadvantages are the weak thermal performance that results in energy wastage. For warm climate applications where space cooling is generally required, there are three basic principles in modern window design:

i. To filter out infrared of the solar spectrum, but not visible light in solar transmission;

ii. To utilize incident solar radiation as a renewable energy source; and

iii. To optimize the design and shorten the economical and energy payback time. For green building or zero-energy building applications, the above lead to the invention of photovoltaic (PV) glazing, which directly converts solar radiation into electricity through embedded solar cells. In PV ventilated glazing, the vented air cavity between the front PV-glass and the clear glass at the back conveys the absorbed solar heat to the outdoor space by natural airflow. The limitations are the trade-off between visibility against electricity output, and the intensification of the urban heat island




116

effect, as well as the unfavourable cost payback time. The better solution can be the use of liquid water rather than moist air as the solar heat-conveying medium in multi-pane windows. As a matter of fact, the thermal capacitance of liquid water is much higher than moist air. This also makes possible an active means of solar application, like for services water heating. Different research teams were exploring the related technologies for more than 10 years, and came out with different design options [Chow, Li & Lin 2010; Gil-Lopez & Gimenez-Molina 2013]. Besides the pumped water circulation options that require precise water pressure control, the natural circulation types successfully limit the fluid working pressure to the static head level. Alternative designs Buoyant-flow double-glazing

Figure 1. Buoyant-flow window design.

Fig. 1(a) shows the basic design. Water-

carrying tubing and distribution headers at the window cavity are connected to a double-pipe heat exchanger positioned at the upper window frame. Under sunlight, the thermosyphon-induced water rises slowly in the glazing cavity to the heat exchanger at the top end for hot water preheating purpose. Solar transmission through the glazing is then reduced, and so space-cooling load is lowered. At the same time, the quality of daylight is maintained since the clear water layer affects extremely small the visible light spectrum. The advantages are then the spacing thermal load

reduction, daylight utilization, and useful heat gain for hot water services.

Buoyant-flow without headers An alternative design is the removal of the upper and lower distribution headers, as in Fig. 1(b). The advantages are in three folds: the reduced cavity space and material use, the reduced overall weight, and the reduced flow friction loss [Chow & Lyu 2017]. The computational fluid dynamic (CFD) analysis shows that the removal of the two headers affects very little the laminar liquid flow pattern and also the vertical temperature stratification within the window cavity.

Figure 2. Temperature distribution after the removal of distribution headers.

Water-bath double-glazing To save further the material use and frame size, the external heat exchanger can be replaced by a horizontal bare-tube heat exchanger submerged immediately below the concealed water level, as shown in Fig. 3. This alternative design changes the fluid flow pattern from laminar upward flow to the cellular flow inside the cavity.

(a) (b)

Double-pipes heat exchanger

Buoyance driven

flow

Upper header

Cold feed

water inlet

Cold feed

water inlet Feed water

outlet

Feed water

outlet

Lower header




117

Figure 3. With submerged heat exchanger.

Fig. 4 shows the CFD results of the steady flow pattern when the outside temperature is higher than the room temperature. In this case, the water flows upward very slowly at positions close to the outer glazing, and downward at the opposite side close to the inner glazing. Because of the direct and effective heat transfer at the horizontal feed water tubing, the water temperature variation at the water bath is less than 0.5oC.

Figure 4. Sectional view of the fluid flow pattern.

Heat exchange performance

The heat flow performance can be evaluated by thermal simulation making use of typical weather data. Explicit dynamic simulation models of the window designs were developed through the controlled volume finite difference method. In our nodal scheme, a single node is used to represent individual glass, liquid and tube layer. This results in a five-node model representation. The computations were done through a self-developed FORTRAN program. The centre of glass performances in typical summer and winter weeks of the ‘buoyant-flow’ and the ‘water-bath’ absorptive double-glazing design were determined respectively. Table 1 Comparison of heat flow and heat gain efficiency

Unit in MJ/m2

Typical week

Water-bath double glazing

Buoyant-flow double glazing

Daily accumulated solar radiation

Summer 71.4 71.4

Winter 68.7 68.7

Water heat gain

Summer 27.5 10.3

Winter 24.3 8.7

Water heat gain efficiency

Summer 38.6% 14.5%

Winter 35.4% 12.7%

Room heat gain

Summer 24.3 25.5

Winter 16.1 16.7

Room heat loss

Summer 0.0 0.0

Winter 8.0 1.4

The result comparisons as listed in Table 1, including the water heat gain and the room heat gain performances using the typical meteorological year (TMY) weather data set (8760-hour) of Hong Kong, a sub-tropical Asian city at 22.3oN and 114.2oE. It can be seen that the water heat gain of the water-bath design is much better than the buoyant-flow design, i.e. 27.5 vs 10.3 MJ/m2 in summer and 24.3 vs 8.7 MJ/m2 in winter. These figures reflect the improvements of 267% and 279% respectively. The improvements in water heat gain efficiency are of the similar level of magnitude. The changes in room heat gain are found relatively small, indicating the space cooling loads are more or less the same. Discussions

Copper tubing

Water-bath double glazing




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Besides the substantial improvements in water heating performance, this innovative water-bath approach carries the advantage of reduced working pressure by eliminating the external heat exchanger at the top. Also the frame structure is much simplified. This makes easy the factory assembly and site installation works. Together with the substantial increase in the useful water heat gain over the entire year, the cost payback period will be much shortened. In fact, the water heating process may take place even at night when either the outdoor or the indoor temperature is higher than the feed water temperature. It is estimated that, based on developed manufacturing processes, the cost payback period of this water-bath type is around 3 years making reference to the normal air-sealed double-glazing type.

More glass panes can be added to the window at places with extreme weather conditions, like cities with hot summer and cold winter. Glycol solution can be used as the working fluid when the outdoor temperature occasionally falls below the freezing point. Alternatively, the water can be emptied in cold winter. The potential of achieving the zero-energy building target is much higher. There can be a range of commercial products in meeting the needs of different building types from commercial to residential in different climate zones. Conclusions Liquid-flow window is a novel multi-glazing designed to deal with the façade thermal weakness problem. A flowing liquid layer within the window cavity is able to reduce the space air-conditioning load and the hot water energy consumption. Such liquid flow can be on either mechanical-flow or buoyant-flow basis. The alternative designs and applications of the buoyant flow types were discussed, together with the introduction of a novel alternative design - the liquid-bath type. The improvements in solar water heating performance of the new novel type is found around 270% for subtropical climate application, like Hong Kong as an illustrating example. The cost payback period is found attractive.

Acknowledgments The work described in this article was financially supported by the Shenzhen Science and Technology Funding Project JCYJ20160229165305551 on fundamental research.

References Chow TT, Li C, Lin Z. Innovative solar windows for cooling-demand climate, Solar Energy Materials & Solar Cells 2010;94:212–220. Chow TT, Lyu YL. Effect of design configurations on water flow window performance. Solar Energy 2017;155:354–362. Floyd AC, Bilka A. Green building: a professional's guide to concepts, codes and innovation, Clifton Park, NY: Delmar Cengage Learning, 2012. Gil-Lopez T, Gimenez-Molina C. Environmental, economic and energy analysis of double glazing with a circulating water chamber in residential buildings. Applied Energy 2013;101:572–581.




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Renewable energy resources for better economics and sustainable living in rural and desert areas

Karl Gatterer1, Salah Arafa2,* 1Graz University of Technology, Graz, Austria; 2The American University in Cairo, Cairo, Egypt; *corresponding author email: [email protected] Abstract Reliable and affordable energy is key for the socio-economic development in rural and desert communities worldwide. While energy can be used for consumption purposes such as lighting, access to information, comfort and entertainment, productive use of renewable energy is the key enabler for SMEs and economy to grow. The paper examines the complex interconnections between Energy - Materials – Water – Food – Building – Employment – Environment. It also discusses the implementation of renewable energy technologies to overcome some of barriers faced by rural villages and desert communities. It shows some of the special applications and approaches used over the past few decades in energy conversion, consumption and conservation to achieve poverty reduction, social justice and sustainable development. Field experiences in Basaisa projects, Egypt, showed that open free dialogues with all stakeholders, site-specific education and training, appropriate local financing systems and access to knowledge are key-elements and essential factors for achieving green economy and sustainable community development. The coming decade will see a continued expansion of knowledge about renewable energy resources and its useful applications as systems friendly to the environment and as tools for economic activities, sustainable living and growth in rural and desert communities.

Keywords renewable energy resources; economic; sustainable living; development; rural and desert

communities; Basaisa; Egypt

Introduction Food, water and energy are three important components of life that we can't live without. Food for example needs water to grow (crops) and with energy you can transport the water to the crops and you can produce energy. It's basically like a cycle made out of three components and each component needs the help of the other two to grow/get produced while it helps the other components back. It's a fact that agriculture uses around 70% of the global water withdrawal, which is a huge amount of water.

Population growth could lead to a shortage in water, which could lead to a shortage in food because the people are more (they need more water and food) but we still have the same amount of water and food that is not enough in some regions. But to prevent that from happening we can use energy to desalinate water and will be able to provide the

water needed. Here again we come to the connection between water, food and energy.

Depletion of fossil fuels is unavoidable because of the existing unbalance between consumption and production of resources. Population increase and demands for development can't be satisfied by the existing resource constraints. The necessity to face the negative impacts of climate change on water, food, and health are the biggest challenges facing humanity. New and renewable energy resources represent our hope to face such impacts and to deal with the present constraints. What is needed is an intelligent mix and some behaviour changes in human activities for a creative balance between consumption and production and for sustainability. Both formal and informal education and training should be employed, and target groups are several: School and university students, politicians and decision makers, media people, business leaders,




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formal and informal leaders, and teachers, to name the most obvious ones. Also appropriate policies and financing approaches are needed to encourage citizens to conserve energies and use renewable energies. The principles for high quality education and training and the roles of the different sectors and groups in the society are shown in the following model.

Figure 0. Model of Education and Training for Sustainable Development. The principles for high quality education and roles of the different sectors and groups in the society.

Field Experimental Work Two case studies (Basaisa village in Sharkiya Governorate) and (New Basaisa community in South Sinai Governorate) exist in Egypt that one of the authors (Arafa) has been engaged in over the past 45 years, as well as on going and present activities [Arafa et al. 1978, 2002 & 2015]. The field work is based on action research and integrated approach. It emphas-izes the importance of high quality community- based education and training, see Figures 1-4.

Figure 1. Dr. Arafa leading one of the weekly arranged community dialogues in the village of Basaisa where all are invited to attend and participate.

Figure 2. A group of Basaisa village children are watching an educational TV program on the communal TV set powered by solar energy (1976).

Figure 3. Solar Energy systems (PV and Solar water heater) installed on the roof top of the common room in the New Basaisa community (1996).




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Figure 4. The computer lab in the technical center of the New Basaisa community. The instructors are volunteers from the university and the attendees are from New Basaisa as well as from other surrounding communities in the area.

Methods The basic interest in doing the field work was a social responsibility towards the development of rural and desert area and to find appropriate approaches in promoting the implementation of renewable energy technologies and to address how community interventions with active citizens participation can improve the human wellbeing and empower poor and illiterate citizens and communities to achieve sustainable development. [El-Simi et al. 1995; El-Tawila et al. 2013 & Prasad et al. 2017]

Important among all the technological specifics were: (a) emphasis on equity; (b) giving priority to community expressed needs; (c) closing the gender gap so females, girls and women, can fully share equal rights and responsibilities; (d) empowering the local NGOs and encourage cooperation between them as well as exchange of experiences and transfer of knowledge; (e) developing appropriate access to finance and soft loans for SME’s; (f) ensure the transparency and social justice in all community meetings and actions.

Emphasis were mainly on the well informed citizens empowered by appropriate community-based education and training to be an active participant and responsible citizen in the process of community development.

Results Experiences showed that well informed and well educated citizens are prerequisite to any sustainable development efforts. Community-based education and training and community-owned systems are key elements in achieving sustainable community development. Discussions Success in the efforts carried in Basaisa have been dependent on the ability of the project leaders and actors to keep the human dimension in all the on-site activities (Arafa,2002) and the delicate balance required for survival between the maintenance of the traditional pattern of values that serves as the basis of cohesion and adaptation to knowledge that requires a revision of the traditional technologies and value system.

It was important to keep our attention firmly focused on the two primary pillars of the community development process: Education and Justice. Both can promote a sense of belonging and commitment and ensure success.

We all know that knowledge is power but half the knowledge is to know where to find it and to get an easy access to it. Conclusions Field experiences showed that open free dialogues with all stakeholders, site-specific education and training, appropriate local financing systems, and access to knowledge are key-elements and essential factors for achieving better economics and sustainable living in rural and desert communities worldwide.

Our shared vision is: Children are the future of our nations, renewables are the future of our planet, education, training, innovation and entrepreneurship are our way towards a sustainable future. Acknowledgments We acknowledge the support of our two University Institutions.




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References Arafa, S., Nelson, C. and Lumsdaine, E. Utilization of Solar Energy and the Development of an Egyptian Village: An Integrated Field Project. A project proposal approved and supported by the US National Science Foundation, Grant No. 78-01127 and sponsored by the American University in Cairo, Egypt (1978) Arafa, S. Sustainable Community Development with Human Dimensions: The Basaisa Experience. Ecological Education in Everyday Life ALPHA 2000, edited by Jean-Paul Hautecoeur, University of Toronto Press, pp. 208-224 (2002). Arafa, S. Renewable energy for sustainable development and poverty reduction: The case of Basaisa, Egypt. TWAS-ARO 11th Annual Meeting “Green Economy: A Road Map for

Sustainable Development and Poverty Reduction in the Arab Region”. December 16-17, (2015), Bibliotheca Alexandrina, Alexandria, Egypt. El-Shimi, S.A. and Arafa, S.M. Biogas Technology for Rural Egypt. Conference on Settling Technology for Industrial and Social Development. Alex. Scientific Committee of the Alexandria Syndicate of Engineers, Jan. 24-26, (1995), Egypt. El-Tawila, S., May, G. and Einas, A. Income Poverty and Inequality in Egypt’s Poorest Villages. The World Bank and Social Contract Center Experts’ Group Meeting, May 27th, (2013), Cairo, Egypt. Prasad, A.R., Singh, S. and Nagar H.

Importance of Solar Energy Technologies for

Development of Rural Area in India. IJSRST

Volume 3, Issue 6 (2017).




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Efficiency modelling of a complex planetary mechanical transmission used in renewable energy systems

Mircea Neagoe 1, Radu Saulescu1,*, Codruta Jaliu1 1Transilvania University of Brasov, Brasov, Romania; *corresponding author email: [email protected] Abstract The wind and hydro systems are two of the most dynamic areas addressed by researchers aiming at increasing their conversion efficiency and at maximizing the use of the available renewable energy potential. In this context, many innovative concepts of wind turbines / hydro systems have been developed, especially of medium and high power, which usually include mechanical transmissions for increasing the speed and transmitting the motion from the input rotors / water turbines to the electric generators. The speed increasers with fixed axes of the component gear mechanisms are typically implemented in practice. But these transmissions have the drawback of larger overall size and lower efficiencies compared to planetary type speed increasers. The paper presents a generalized modelling of the efficiency of complex mechanical transmissions composed by two planetary gear mechanisms intended for integration in wind turbines or hydro systems with two counter-rotating rotors and a fixed-stator electric generator. The kinematic and static modelling of a transmission with single satellite carrier is described, further used to obtain the efficiency analytical expression, along with numerical simulations of the efficiency and output power. Keywords renewable energy system; wind turbine; hydro system; speed increaser; planetary transmission; kinematic modelling; static modelling; efficiency; kinematic ratio Introduction The problem of increasing the efficiency of wind or hydro systems has been addressed by many researchers, who proposed various solutions to optimize their performance by developing new concepts of wind rotors / water turbines, more efficient mechanical transmissions, more compact and more efficient electric generators. A relatively recent research direction addresses the counter-rotating wind systems (Oprina et al. 2016, Climescu et al. 2011), capable of using the wind potential at a higher level, which integrates a wide range of innovative solutions of speed increasers (Hall et al. 2011, Jelaska et al. 2015, Neagoe et al. 2017). Planetary transmissions are well suited for these applications, ensuring high kinematic ratios along with low overall size and high efficiency (Qiu et al. 2017, Saulescu et al. 2016b). Moreover, the counter-rotating wind systems can be developed with various types of speed increasers, as the 2 degrees of

freedom (DOF) gearboxes (Herzog et al. 2010, Saulescu et al. 2016a) and the 1 DOF gearboxes [Neagoe et al. 2019, Saulescu et al. 2018].

Considering the case of the wind turbines with two counter-rotating rotors and a classic generator, the paper presents a generalized algorithm for modelling the efficiency of 1 DOF speed increasers obtained by connection of two 1 DOF planetary gear sets.

Efficiency modelling in a general case The general case of a speed increaser type obtained by connecting two planetary gear sets (PU) I and II, according to Figure 1, is further considered. The transmission has three external links: two inputs connected to the counter-rotating wind rotors R1 and R2, and an output coupled to the shaft of an electric generator G.




124

Figure 1. Block scheme of a complex 1 DOF planetary transmission with two inputs and one output.

This transmission type is a 1 DOF mechanism and thus has the following speeds and torques transmission functions:

1RG a ; 12 RR b (1)

21 RGR BTATT (2)

where ωR1,2 is the angular speed of the wind

rotor R1,2; ωG – the generator angular speed;

TR1,2 – the torque generated by the wind rotor

R1,2; TG – the torque on the generator shaft; a,

b, A and B are constant values.

The transmission efficiency η can be

obtained using (Saulescu et al. 2018):

21

21

2211 RR

RR

RRRR

GG

bTT

BTT

A

a

TT

T

(3)

and considering the input torques ratio:

21 / RRt TTk (4)

the general relation of the efficiency becomes:

bk

Bk

A

a

t

t

(5)

By zeroing one of the two input torques (TR1 or TR2), i.e. the elimination of a wind rotor or by properly adjusting the pitch angle of its blades, the transmission remains with two external links (only one active rotor) and its efficiency has the following particular expressions: a) for kt = 0 (i.e. TR1 = 0, TR2 ≠ 0) the minimum value of the efficiency is obtained:

b

B

A

amin (6)

b) for kt = (i.e. TR2 = 0, TR1 ≠ 0) the maximum value of the efficiency results:

A

amax (7)

The constant parameters a, b, A and B can be obtained according to the specific structure of the speed increaser: the type of planetary gear sets I, II and their connections.

Application of the generalized efficiency model A variant of the planetary speed increaser of the type presented in Figure 1 is depicted in Figure 2, in which the parallel power flows from inputs to output are highlighted. The transmission contains two planetary gear sets I (1-2-3-5-6-H) and II (4-3-5-6-H), in which H is the common satellite carrier of the two satellite gear sets, 1, 4 and 6 are sun gears, and 2, 3 and 5 are satellite gears.

a)

b)

Figure 2. Example of a complex 1 DOF planetary speed increaser: a) structural scheme, b) block scheme

The transmission has two serial satellites (2 and 3-5), a common solution for planetary transmissions with large transmission ratios. The two component planetary gear sets I and II are characterized by the interior kinematic ratios i0I and i0II, and by the interior efficiencies η0I and η0II.

The transmission efficiency is described by Relation (5), in which the expressions of the parameters a, b, A and B are obtained through kinematic and static modelling. Kinematic coefficients

ωG

ωR1

TG

TR1 ωR2

TR2 R2

R1

G

II

I

H

3

2

4

1

ωR1

TR1 R1 G

6≡0

5

ωG

TG

ωR2 TR2 R2

ωG

ωR1

TG

TR1 ωR2

TR2 6 ≡ 0

H 4 1

H

i0II

η0II i0I

η0I




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According to Relation (1), the coefficients a and b are the kinematic ratios:

IH

HRGR

G iiia 06

16611

1

1

(8)

IIH

HRRR

R iiib 06

466412

1

2 1

(9)

where zxyi is the transmission ratio from

element x to y, element z being considered as

reference, xy - the relative angular speed

between elements x and y, and the interior kinematic ratios i0I and i0II are given by:

5

6

1

3

6

1160

z

z

z

zii

H

HHI

(10)

5

6

4

3

6

4460

z

z

z

zii

H

HHII

(11)

Static coefficients

According to Relation (2), the coefficients A and B are obtained by effects superposing, considering the torques TR2 and TG null one at a time. a) case TR2 = 0: the mechanical power is transmitted with friction from R1 ≡ H to G ≡ 1, according to the energetic equilibrum equation considering friction:

061

)(11 GGHG

RR TT (12)

of which, corroborated with Relation (2), it results:

IH

RG

G

GR i

i

T

TA 06

1

1)(

1 1

(13)

where (Saulescu 2018):

I

IG

RR

GGH

i

i

T

T

0

0)(

11

61

1

1

(14)

1

000 III ii ;

HHH

I 5623120 (15)

where )(1G

RT is the torque at the R1 shaft when

all the other external torques are null except

the TG torque, zxy - the efficiency for the power

transmission from element x to y having z as the reference element. b) case TG = 0: the mechanical power is transmitted with friction between the rotors R1 ≡ H and R2 ≡ 4. From the energetic equilibrum equations with friction:

02264

)2(11 RRHR

RR TT (16)

it results:

IIHRRR

RR iiT

TB 0

6412

2

)2(1 1 (17)

where:

II

II

RR

RRR

Hi

i

T

T

0

0

22

)2(116

41

1

(18)

IIIIII ii 000 ; HH

II 56430 (19)

Speed increaser efficiency The general form of the speed increaser efficiency is obtained by replacing the expressions from Relations (8), (9), (13) and (17) in Relation (5):

IIt

IIt

I

I

ik

ik

i

i

0

0

0

0

1

1

1

1 (20)

from which its particular forms derive:

I

II

II

Imin

i

i

i

i

0

0

0

0

1

1

1

1

(21)

I

Imax

i

i

0

0

1

1

(22)

Numerical results and discussions

A numerical application of the planetary speed increaser from Figure 2 is further considered:

90 Ii , 20 IIi , H12 H

23 H43 95.056 H ,

12 R rad/s and 12 RT kNm (i.e. the power

generated by the wind rotor R2 equals 1 kW). A variation of the kt ratio between 0...2 is also considered, which corresponds to the usual situations in practice. Under these conditions, the following values of the main parameters are obtained: a = -8, b = -1, A = 9.5, B = 0.8, ηmin = 0.67, ηmax = 0.84. Because b = -1, the two wind rotors rotate in opposite directions with equal speeds.

The variation with the kt ratio of the efficiency and of the output power are presented in Figure 3. The results show that both the transmission efficiency (Figure 3a) and the output power (Figure 3b) increase with the increase of the kt ratio (i.e. with the increase of the R1 wind rotor torque). For example, for kt = 1, an output power of 1.52 kW is obtained at an efficiency of 0.76, for a cumulative input power of 2kW.




126

a)

b)

Figure 3. Variation in relation with kt of: a) the efficiency, b) the output power

Conclusions The paper presents a generalized algorithm for modelling the efficiency of 1 DOF speed increasers composed by two planetary gear sets, with application for single satellite carrier transmissions. The obtained results highlight the following conclusions:

The wind turbines with counter-rotating

rotors are used for increasing the output

power and thus for a better use of the wind

potential;

The speed increasers with parallel power

flow have higher efficiency than the case of

the serial flow;

The efficiency increases with the increase

of the kt ratio;

The planetary speed increasers are

compact and can ensure high kinematic

ratios and efficiencies.

References

Climescu O, Saulescu R, Jaliu C. Specific featues of a counter-rotating transmission for renewable energy systems. Environmental Engineering and Management Journal 2011; 10:1105-1113. Hall JF, Mecklenborg CA, Chen D, Pratap SB. Wind energy conversion with a variable-ratio gearbox: design and analysis. Renewable Energy 2011; 36:1075-1080. Herzog R, Schaffarczyk AP, Wacinski A, Zürcher O. Performance and stability of a counter–rotating windmill using a planetary gearing: Measurements and Simulation. EWEC 2010; 6(6):4847. Jelaska D, Podrug S, Perkusic M. A novel hybrid transmission for variable speed wind turbines. Renewable Energy 2015; 83:78-84. Neagoe M, Saulescu R, Jaliu C. Design and Simulation of a 1 DOF Planetary Speed Increaser for Counter-Rotating Wind Turbines with Counter-Rotating Electric Generators. Energies 2019; 12:1754. Neagoe M, Saulescu R, Jaliu C, Cretescu N. Novel speed increaser used in counter-rotating wind turbines. Mechanisms and Machine Science 2017; 46:143-151. Oprina G, Chihaia RA, El-Leathey LA, Nicolaie S, Babutanu CA, Voina A. A review on counter-rotating wind turbines development. Journal of Sustainable Energy 2016; 7(3):91-98. Qiu J, Liu B, Dong H, Wang D. Type Synthesis of Gear-box in Wind Turbine. Procedia Computer Science 2017; 109C:809–816. Saulescu R, Jaliu C, Neagoe M. Structural and kinematic features of a 2 DOF speed increaser for renewable energy systems. Applied Mechanics and Materials 2016a; 823:367-372. Saulescu R, Neagoe M, Munteanu O, Cretescu N. Performance analysis of a novel planetary speed increaser used in single-rotor wind turbines with counter-rotating electric generator. Materials Science and Engineering 2016b; 147(1):012090. Saulescu R, Neagoe M, Jaliu C. Conceptual Synthesis of Speed Increasers for Wind Turbine Conversion Systems. Energies 2018; 11:2257.




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A study of the reliability of Medina date palm parts as thermal insulator in buildings

Khaled S. AlQdah1,*, Raed Alahmdi1, Abdurrahman Almoghamisi1, Abdurrahman Alanssari, 1Mohanad

Abualkhair1, Abdullmajeed Alhazmy1, Nasser Alnuman1

1Taibah University, Mechanical Engineering Department, Madinah, KSA Abstract In this work an experimental study on the thermal conductivity of composite material of the date palm mixed with conventional building materials has been carried out in Medina region. The investigation was conducted to study the use of palm’s leaflet and trunk fibers as thermal insulation to replace the conventional thermal insulators that have a negative impact on the optimum utilization of renewable energy sources for heating or cooling the buildings. Three different samples were prepared using suitable molds, these samples consist of different fraction of cement, gypsum, sand, glue in addition to date palm fiber and leaflet. Each sample was tested under certain temperatures, density and time to estimate the thermal conductivity K for the new composite. The thermal conductivity varied with sample density and found to be between 0.048 to 0.162 W/mK for sample 1 where the density varied between 141.97 to 42.6 kg/m3 and for sample 2 between 0.055 to 0.193 W/mK and for sample 3 varied from 0.058 to 0.186 W/mK. Comparison was made between the heat transfer of the best specimen at higher density and between the heat transfer through traditional and common type of concrete that is used in buildings. The reported results show that the new insulation reduced the rate of heat transfer 4 times which means decreasing in energy consumption required to cool or heat the building. This will enhance the building energy performance and safe the renewable energy resources to be utilized efficiently by reducing the greenhouse emission by capturing and sinking the CO2 and other undesirable gases. Keywords Palm fiber; insulation; thermal conductivity; building materials Introduction Medina region was characterized by dry and hot climate in summer and most of the building materials in this region consist of concrete, mortar cement, gypsum board and conventional thermal insulation. This leads to high energy consumption to cool the buildings and to solve this problem, thinking to replace these conventional building materials with low cost composite material is the motivation of this work.

Date palm has been known as long as

recorded history for its important uses as food

and fiber source [1] in addition to that, in 2011,

Kingdom of Saudi Arabia (KSA) ranked top of

the world regarding the number of date palm

trees [2], the total number of palms in KSA

exceeds 25 million palms, covers more than

170 thousand hectares [2]. This is a huge

number of trees, which make a huge number of

leftovers of leaflet of palm and trunk after the

trees dies. This leftover and waste can be used

in different applications such as thermal

insulation when it mixed with the building

materials. The building sector in KSA

represents a large number of the total energy

consumption due to the increasing demand

especially in summer. Thermal insulation is one

of the most important, cost-effective, energy

saving building materials in a home. In fact,

without thermal insulation, some of the other

energy-efficient components in a home won’t

perform as intended. Thermal insulation can be

used as a thermal and acoustical solution in the

walls, ceilings, floors, and attics of a home or

every part of the building envelope and is




128

perhaps the most cost-effective way to lower

energy bills. Most of the thermal insulating

materials used in Medina are made of glass

wool, rock wool, polystyrene and polyurethane

(rigid foam). In spite of these materials have

low thermal conductivity, they are still cost in

addition, these materials can be hazardous to

human health and bad impact on the

environment. Therefore, focusing on new

materials with low thermal conductivity as well

as low cost is the main objective of this work.

Therefore, date palm leaflet and trunk fibers

are a good replacement, since they have been

used as thermal insulator in old buildings and

homes along with soil which potential and

economic benefit instead of waste. Therefore,

this research will conduct and test the thermal

conductivity and the reliability of palm material

to utilize it as thermal insulation in buildings.

This will support the idea of utilizing materials

with low environmental impact. The

performance of using date palms as insulator

mixed with traditional buildings materials

conducted by Al-Juruf, et al, 2018 [3]. El

Ashmawy etal,2018 [4] showed that more than

17 million palms in Egypt, the elements of

these palms can be used as insulation.

Mohamed Ali and Abdullah Alabdulkarem,

2017 [5]. Proposed a new building insulation

material from the palm fiber, the thermal

conductivity for this material found to be

between 0.0457 and 0.0697 at different

densities. Nadia Benmansoura et al 2014 [6] a

new insulating material composed of cement

and palm fiber with different weight has been

investigated. Abu-Jdayil et al, 2019 [7] studied

the thermal and physical characteristics of Date

Pits Powder extracted from UAE University

farm in AlFoah mixed with polystyrene. Clara-

Eugenia et al, 2018 [8] investigated

experimentally the particleboard obtained

from the palm trees. H. Fouli et al, 2014 [9]

conducted an experimental study to evaluate

the use of palm based as insulator for the

overhead water tanks in arid regions. From the

previous literature review, it can be seen none

of these works investigated the potential of

utilizing the date palm parts as insulation

material mixed with conventional and available

building materials which is our main goal in this

work. Therefore, the aims of this work is to

study the date palm parts thermal insulation by

examining the thermal conductivity of this

material.

Materials and method

The main objective of this work is to investigate the potential of date palm parts to be an insulator with low impact on the environment and positive impact on the utilizing of renewable energy resources .

Figure1 shows the date palm and its main components used in this investigation [1]. In this study, three different attempts were made to accomplish this study and three samples constructed from cement, gypsum, saveto glue, sand and palm different leaves and trunk fibers. The collected trunk fibers and leaflet are cleaned using water so that any dust or impurities are removed. The molds were designed and manufactured with different sizes to handle the samples for testing. The percentage of the components of each specimen can be determined by following procedure: To measure the thermal conductivity and other thermophysical properties, the designed and fabricated molds made of steel were used to prepare the samples according to the GUNT WL 376 device and standards. This device was used to measure the thermal conductivity and other thermophysical properties. The weight of each sample was measured as well as the density and dimensions. The temperature on the sample sides were set be as 25 ºC and 60 ºC which is reasonable for buildings in the hot environment of Saudi Arabia and Medina region. Each sample was tested for more than hour.

https://journals.sagepub.com/doi/pdf/10.1177/109719638801100304




129

Figure 3. Date palm and its main parts

All the samples have the same length and width but variable thickness are placed between two hot and cold plates. The hot plate is heated by an electric heater while the cold plate temperature is achieved by cold water circulation. The heat flux between the hot plate and the cold plate passes through the sample was measured by a special heat flux sensor. The measured values are transmitted directly to a PC via USB where they can be analyzed using the software include. The obtained results were tabulated and analyzed in the figures and tables.

Results and discussion

An experimental investigation has been carried out to investigate the possibility use of palm parts as thermal insulation material added to the conventional building materials from the test results for sample 1 at density142.97 kg/m3. The performance of the insulators was evaluated based on the measured values of thermal conductivity under variable density. The results of the experiments indicate that this material is a promising material for building insulation because its cost-effective and safe. Figure 2 display the variation of thermal conductivity with time and temperature as well. After one hour the thermal conductivity remains constant with time and the cold plate temperature will remain constant where the heat flow through

the specimen slightly changed or it can be considered as constant due to small variation.

Figure 2. Thermal conductivity of specimen vs Time in minute

The variation of materials thermal

conductivity with density can be seen clearly in

figure 3. From this figure the low thermal

conductivity measure for sample 1 is 0.048

W/mk at the density of 42.6 kg/m3 and for

sample 2 the best thermal conductivity 0.055

W/mk at the density of 28 kg/m3 and for

sample 3 the best thermal conductivity 0.056

W/mk measured at the density of 50 kg/m3. So,

these values can be considered as promising

insulation materials because the thermal

conductivity for concrete and conventional

block are 0.78 and 0.35 W/mk respectively

[10].

Figure 3. The variation of thermal conductivity with

density for the three samples

-0,02

0

0,02

0,04

0,06

0,08

0,1

0,12

0,14

0,16

0,18

0 20 40 60 80

Ther

mal

co

nd

uct

ivit

y(W

/mK

)

Time (min)

0

0,05

0,1

0,15

0,2

0,25

0 50 100 150 200

Th

erm

al C

on

du

ctiv

ity (

W/m

k)

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Thermal Conductivity Vs Density

Sample 1

Sample 2

Sample 3




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Conclusions Date Palm’s leaflet is considered as waste or leftover after the palm dies, that what makes it almost free material for insulation, which was proven by this investigation. Three different samples of building components were mixed with of the date palm parts either the leaflet or the fibres of the trunk. The thermal conductivity for sample 1 varied between 0.048 and 0.162 for the density ranges between 42.6 to 141.97 kg/m3 and for sample 2 between 0.055 to 0.193W/mK at the densities 28 to 112.8 kg/m3. For sample 3 it was found the best thermal conductivity 0.056 at density of 50 kg/m3. The obtained results were satisfied and showed that this material is temperature and density dependent material. The heat flux through these samples were measured using standard device. Testing the performance of the highest thermal conductivity of sample 1 with specified wall dimensions showed with an approximated heat transfer rate Q of 184.2 𝑊 which reduce the rate of heat transfer from the wall to about 4 times when it compared with using normal concrete that is used in buildings. This will lead to building energy saving and reduce the cost of electricity and energy that can be used for cooling or heating. The cost of the material is almost uncountable, and this material can be considered as an efficient thermal insulator. This material can be consider as promising material and has a potential to replace the traditional building materials by enhancing their thermal performance. Recommendation to study the water absorption as well as strength performance for these materials. References [1] E. I. Hernández, M.T. Ferrer, J. N. Pedreño, I.M. Pastor, and I. G. Ancient sustainability use of 'the palmeral of elche' and the current unsustainabilty: Reasons for a sustainable future. Available from: https://www.researchgate.net/figure/a-Parts-of-a-date-palm-and-b-Date-palm-leaf-characteristics.

[2] Al-Redhaiman, Khalid PY - 2014/07/29SP - T1 - Date Palm Cultivation in Saudi Arabia: Current Status and Future Prospects for Development ER [3] R.S. Al-Juruf, F.A. Ahmed, I.A. Alam, H.H. Abdel-Rahman, Development of Heat Insulating Materials Using Date Palm Leaves, Journal of Thermal Insulation, Volume: 11 issue: 3, 158-164, 1988. [4] El Ashmawy, N. M.; M. F. Zayed and Samera S Kassem, Thermal Properties of Palm Fronds (Krino) for Utilizing as a Thermal Insulation Material, J. Soil Sci. and Agric. Eng., Mansoura Univ., Vol. 9 (12): 859 - 863, 2018. [5] Mohamed E. Ali, Abdullah Alabdulkarem, on thermal characteristics and microstructure of a new insulation material extracted from date palm trees surface fibers. Construction and Building Materials, 138 (2017) 276–284. [6] Nadia Benmansoura, Boudjemaa Agoudjila, Abdelkader Gherablia, Abdelhak Karechea, Aberrahim Boudenne, Thermal and mechanical. performance of natural mortar reinforced with date palm fibers for use as insulating materials in building, Energy and Buildings 81 (2014) 98–104. [7] B. Abu-Jdayil, W. Hittini, and A.H. Mourad, Development of Date Pit–Polystyrene Thermoplastic Heat Insulator Material: Physical and Thermal Properties. International Journal of Polymer Science , 2019, Article ID 1697627. [8] C.E. García, A F.García ,M. F.Villena, J. F. Hidalgo, T.G.-Ortuño and M.T. Ferrández.. Physical and Mechanical Properties of Particleboard Made from Palm Tree Prunings. Forests 2018, 9, 755; doi:10.3390/f9120755. [9] H. Fouli ∙ A. A. Alshaikh ∙ J. Nurdin ∙ S. Alam ∙H. Alnaimat, Evaluating the Use of Palm-Based Insulators for Reducing Peak Water Temperatures During Summer and for Saving Energy During Winter in Existing Overhead Storage Water Tanks. Arab J Sci Eng (2014) 39:4473–4484, DOI 10.1007/s13369-014-1047-1 [10] Holman, J. P. "Heat Transfer" ,10th Edition, McGraw-Hill, Inc, New York, NY 10020. (2011.)









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Low carbon Arctic smart community: the ultimate case study of an Arctic renewable energy perspective

Gisele M. Arruda1,* 1Coventry University London, London, UK; 2Anvivo.org, London, UK; *corresponding author email: [email protected]; [email protected] Abstract The Alaskan smart-grid projects reflect a great effort of local experts and a significant contribution to manage local and regional energy demand flows, optimize energy use, minimize fossil fuels impacts from diesel generators and create a low carbon Arctic smart community based on a decentralized-type of renewable energy system relying on advanced storage and metering systems. The stabilization, efficiency and integration of the Alaskan Renewable Energy smart-grids offer new challenges and opportunities for the years ahead and is the ultimate case study of socio- technical energy systems co-evolving with smart technological solutions, co-management approaches, contemporary energy policies with a perspective of application at global scale. Keywords renewable energy; smart-grids; environmental impacts; socio-technical energy systems; smart communities

Introduction The challenges and risks posed by fossil fuels exploitation ventures and the additional layer of risks posed by climate change served to amplify the understanding of how energy production/use is linked to local social processes and, ultimately, to sustainable development. Main body The importance of a low carbon Arctic energy system has motivated the debate and initiatives related to the latest technological and innovative energy approaches from pioneering and leading stakeholders from different parts of the Arctic. The research focuses on energy integration, infrastructure of communities, investments, and corporations’ projects in energy transition are shaping energy policies and the well-being of Arctic communities. This pioneering case study has relevant implications for enhancing understanding in socio-technical systems.

Methods This paper is the outcome of 10 years of fieldwork in the Arctic which involved visiting urban and remote communities with the aim of understanding and mapping the Arctic energy systems and the opporutnities and challenges of a renewable energy system for the Arctic. Insights from the existent literature were analysed jointly during interviews with scholars, community members and energy professionals ‘ in loco’ which helped create a platform of ideas and strategic cases studies on the paths of a renewable energy future for the Arctic region. Results A broad perspective of Arctic renewable energy resources involves solar, wind, geothermal, hydro and biomass, while the most popular renewable energy sources comprehend three basic types, solar energy (direct solar and wind), tidal energy and geothermal energy. Obviously, the potential and modalities of energy developments vary on a regional scale, but this is the start of a systematic




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transformation based on transition management. Some Arctic nations have taken this invaluable opportunity to address the challenges of current energy transition process and have been promoting effective changes in how the Arctic energy system is viewed by creating a new energy platform based on renewable energy resources. Discussions The new perspective associated to the decentralization of electricity systems as a core component of the Alaskan smart grid energy projects (Arruda and Arruda, 2018) illustrates how co-evolutionary processes of technology and societal issues are. The destabilization of the Arctic systems created a window of opportunity to an incremental change where the local actors (energy professionals, investors, entrepreneurs, communities) decided to coordinate resources available to adapt to real world pressures and needs (Smith et al., 2005) by constructing transition paths and re-aligning to new social-technical systems. This transition path originated what is called the low carbon Arctic smart community base on renewable energy systems. Conclusions The technological and innovative energy approaches from the pioneering Alaskan Renewable Energy smart grids not only have

shifted energy production and use from fossil fuels to a more sustainable path, but also have provided a new horizon of durable energy access to Alaskan remote communities. The stabilization, efficiency and integration of the Alaskan Renewable Energy smart-grids offer

new challenges and opportunities for the years ahead and is the ultimate case study of socio-technical energy systems co-evolving with smart technological solutions, co-management approaches, contemporary energy policies with a perspective of application at global scale. Acknowledgments

Thanks to all the Arctic people (participants in

research and collaborators). All of them are

major contributors to our sustainable future of

knowledge and prosperity.

References

Smith, A., Stirling, A. and Berkhout, F. (2005) ‘The governance of sustainable sociotechnical transitions’, Research Policy, 34, 1491-1510 Arruda, G.M. and Arruda, F.M. (2018) ‘Towards sustainable energy systems through smart grids in the Arctic’ in Arruda, G.M. (ed) (2018) Renewable Energy for the Arctic: New Perspectives. Routledge, Abingdon




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A logistic regression approach to model the willingness of homeowners to adopt sustainable energy technologies in different countries

Diana Londoño-Pulgarin1,*, Gabriel Agudelo-Viana2, Francisco Muñoz-Leiva 3, Esmeralda Crespo4

1,3,4University of Granada, Granada, Spain; 2University of Antioquia, Medellin, Colombia; *corresponding author email: [email protected]; address: Campus Universitario la Cartuja,

s/n. 18071. Granada, Spain.

Abstract This study contributes to previous research on the adoption behaviour of renewable energy used for

residential heating. The results provide a basis for organizational communication strategies of this type

of sustainable technologies in different countries, according to international vision of sustainable

development. A theoretical purchase model is supported by this empirical work based on logistic

regression (Logit) where the influence of different factors and emotional/cognitive pro-environmental

mobilizers were identified and tested; individuals’ environment protection perceptions and beliefs are

triggered whenever the purchase and adoption of sustainable thermal energy technologies occur. To

carry out this research, 898 owners of single-family homes from six different countries (Spain, The

United States, The United Kingdom, Switzerland, France and, South Africa) were surveyed.

Keywords environmental sustainability; clean renewable energies; renewable heating; adoption and diffusion

strategies; consumer behaviour

Introduction The seriousness of global warming and its effects has been universally highlighted. Achieving the UN’s Sustainable Development Goals (SDGs) have led to different strategies, business practices and environmentally-friendly systems, such as the clean energy technologies (CETs). Those goals can be achieved through long-lasting changes in society´s lifestyles, reinforced by the development of global public policy plans linked to an international sustainable vision. Despite the efforts to promote sustainability and the adoption of CETs, their diffusion is still limited however, fossil fuels consumption remains predominant. Literature in the field indicates that, the attitudes of individual play a critical role in the diffusion and adoption of CETs; their final decision will depend on cognitive, affective and behavioural components based on their environmental awareness. Therefore, it is necessary to understand the factors that influence the

purchase and adoption of sustainable energy systems.

The present study contributes to

previous research related to the adoption

behaviour of clean and renewable energy used

for residential heating. A CET purchase model

is supported by this empirical work based on

logistic a regression where the influence of

different factors and emotional/cognitive pro-

environmental mobilizers were identified and

tested in accordance with the international

vision of sustainable development. The results

provide a basis for the diffusion of this type of

domestic systems and contributes to the

accomplishment of the SDGs worldwide.

Research Description Sustainable Energy Technologies Adoption Behavioural Factors Environmental concern has led to the spreading of scientific studies in order to find different alternatives towards its protection




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(Delafrooz et al., 2014). Given this, interest on understanding the factors influencing the purchase of sustainable technologies and the adoption of environmentally-friendly practices has also grown; a variety of behavioural models have been empirically tested as well (Frederiks et al., 2015). Previous research on CETs address the influence of sociocultural and psychological factors (Poortinga et al., 2004). At a demographic level, Mahapatra & Gustavsson (2007) indicated that the installation of new energy systems increase as the owners’ income level rises (p. 85).

Kalafatis et al. (1999) argues that, as psycho-behavioural factors of people get affected, they show different conduct and therefore, they become more receptive to pro-environmental diffusion strategies. Other studies indicate that the success on the CETs adoption depends on the adopters’ degree of satisfaction (Nyrud et al., 2008), their technology´s prior knowledge (van Rijnsoever & Farla 2014) and the level of environmental issues awareness (Kaiser et al. 1999; Laroche et al. 2001; Wesley-Schultz 2001; Tonglet et al. 2004; Tilikidou 2007).

In sum, homeowners compare the different energy systems to find the one that seems most advantageous taking into account the diversity of attributes (Mahapatra & Gustavsson, 2007, p.78). Systems with a greater perceived advantage will be adopted by more owners than systems with smaller ones (Rogers, 2003; Dieperink et al., 2004). Proposed Theoretical Model Since the objective of this work is to study the homeowners’ adoption behaviour of sustainable energy technologies in different countries, a dependent variable (Y) rises, as the homeowner’s willingness to adopt renewable residential heating systems, as a form of clean energy technology. A score of one (1) was given when the consumer i is willing to adopt the CETs in his/her residence; while the score of 0 (zero) was given to the opposite answer. In the set of independent variables (Xj y Zj), Xj’s, variables are categorical (11 in total) and the Zj’s variables are numerical. The model is then as follows:

Y = β0 + β1X1 + β2X2 + β3X3 + β4X4 + β5X5 + β6X6 + β7X7

+ β8X8 + β9X9 + β10z12 + β11z13 + β12z14 + β13z15 +

β14z16 + β15z17 + β16z18 +ε

where β0 is a constant; βj is the regression coefficient (j = 1 … 16); X1 is a dummy variable

for Education Level of the family’s head (0 if homeowner has not completed university studies and 1 in the opposite case); X2 is a

dummy variable for Gender (0 if the homeowner is a female and 0 if male); X3 is a

metric variable for the homeowner’s age in different categories; X4 is a metric variable for

the Number of inhabitants in the residence including homeowners (in different ranges); X5 is a dummy factor that indicates whether the residence has received any Incentive or Subsidy for the purchase or installation of its current heating system; X6 is a dummy

variable that indicates the homeowner´s Environmental Knowledge (0 if homeowner knows and y 1 otherwise); X7 is a factor known

as the Subjective Norm where, through a 5-point Likert scale, the influence of family members or friends on homeowners to adopt heating systems based on renewable energy sources is measured, that is, if they feel encouraged by them to do so; X8 is a factor where, through a 5-point Likert scale, the Perception about the Price of energy technology is measured; X9 is a variable

where, through a 5-point Likert scale, the homeowner Level of Satisfaction with his/her current heating system is measured; dimensions Z12 to Z18 were obtained as

mentioned in the previous paragraph (table 2); and ε is an error term.

Study Descriptive Analysis To carry out this research, 898 owners (over 19 years old) of single-family homes from six different countries (Spain, The United States, the United Kingdom, Switzerland, France and South Africa) were surveyed (sociodemographic descriptions in table 1).

Table 1 Sociodemographic characteristics of respondents.

COUNTRY

US UK FR SP SW SA

Education Level

Unschooled 0 0 1 1 5 0

High school 32 46 59 51 52 27

Lower University Degree 64 51 98 54 53 60

Higher University Degree 64 29 25 22 32 40

Other studies 3 1 5 1 14 8

10 € or less 4 10 12 10 6 13




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Annual Income (Thousand Euros)

11 -30 15 23 57 51 10 34

31 -50 25 39 65 46 14 37

51- 70 29 34 30 13 32 20

71- 100 55 14 17 9 44 15

> 100 35 7 7 0 50 16

Gender Female 93 75 81 72 43 79

Male 70 52 107 57 113 56

Age 20-30 34 20 29 26 6 27

31-40 55 35 56 36 27 42

41-50 21 30 47 28 35 33

51-60 20 12 23 28 41 23

61-65 11 6 10 6 18 7

66-70 12 8 18 3 17 2

> 70 10 16 5 2 12 1

US: The United States; UK: The United Kingdom; FR: France; SP: Spain; SW: Switzerland; SA: South Africa

Likewise, the individuals’ knowledge on renewable energy sources was: about 94% of the respondents were aware of solar energy; about 88% were aware of wind energy, 76.5% of hydropower; 61.1% of geothermal energy, 48.4% of tidal or wave energy and, biomass was the least known (46.8%). Methods The Logistic regression (Logit) was used to analyse and estimate the proposed purchasing behaviour model towards sustainable energy technology in each country. The theoretical model was tested and validated with SPSS v.21 & STATA v.15 software. In order to identify differences in the Likert scales chosen by the surveyed subjects and in some variables of the study, an invariance factorial analysis was carried out using the SEM methodology (Structural equation model) in STATA v.15 based on the chi-square difference (LR test of model vs. saturated: chi2 (4640) = 22252.98, Prob> chi2 =0.0000). According to Young (1981), in order to eliminate the response bias caused by the different cultural perceptions in the 6 countries studied, the answers were standardised via optimal scaling in SPSS v.21, and the dimensions were moved to a new scale of 0 to 100 to make it more interpretable. These already quantified categories went through a Principal Components analysis (PCA) in order to obtain the indicator that allowed to perform another type of traditional multivariate analysis.

The logit transformation is defined for

the logistic model under the following

mathematical concepts, where p is the

probability based on the explanatory variables.

( )log ( ( ) ( )

1 ( )

p xit p x Ln

p x

The model for the logit transformation

on p (x) would be

log𝑖𝑡(𝑝(𝑥) = 𝐿𝑛(𝑝(𝑥)

1 − 𝑝(𝑥)) = 𝛽1𝑋1+. . . 𝛽9𝑋9 + 𝛽10𝑍12+. . . 𝛽16𝑍18

The response variable Y is a dummy

factor that measures the type of CETs adopter

of (current or potential), which in terms of p (x)

𝑝(𝑥) =𝐸𝑥𝑝(𝛽1𝑋1+. . . 𝛽9𝑋9 + 𝛽10𝑍12+. . . 𝛽16𝑍18)

1 + 𝐸𝑥𝑝(𝛽1𝑋1+. . . 𝛽9𝑋9 + 𝛽10𝑍12+. . . 𝛽16𝑍18)

Results and discussions Only five independent variables are statistically significant (Table 2): X5, Z13 & Z17 (which are at the levels of 0,1%) and X2 & X9 (are at the levels of 20%). The model gives the Nagelkerke R2(Nagelkerke,1991) of 0.77 and Cox & Snell R2 of 0.578; both considered as high. It means that the independent variables could explain 77% of the total (100%) variability of the dependent variables. On the other hand, the Hosmer and Lemeshow test (1980) shows that the model is significant: the model has a significance value of 0.350, which is above the significance level of 5%. The logit regression model results indicated 3 highly significant factors (Levels of significance at 0.1%) which will have a considerable influence on the homeowners’ willingness to adopt sustainable energy technologies focused on residential heating systems in users located in the studied countries. Therefore, the residential clean heating systems purchase or their installation’s incentives received by homeowners is one of those determinants (X5). Another relevant variable is the individual’s prior knowledge about renewable energy sources (Z13), and on the third place, the ecological concern about the technological impact measured through the Spatial Impact Construct as an attribute that influences a user to choose a CET´s (Z18). On the other hand, the gender (X2) and the level of satisfaction with current heating system (X9) also influence the adoption of CETs; these variables are admitted as well up to 20%. However, the rest of the variables (Table 2) are not statistically significant. Table 2 Logistic regression result.




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Y Coef Std Err. z P>z [95% Conf. Interval] Exp (b)

X2 -0,36 0,26 -1,37 0,17 -0,87 0,16 0,70

X5 1,14 0,31 3,71 0,00 0,54 1,74 3,12

X9_NDS -0,05 0,69 -0,07 0,95 -1,40 1,31 0,95

X9_S 0,80 0,56 1,43 0,15 -0,30 1,90 2,23

Z13 -0,03 0,01 -3,81 0,00 -0,04 -0,01 0,97

Z17 -0,02 0,01 -2,50 0,01 -0,03 0,00 0,98

X9: Level of Satisfaction with his/her current heating

system (NDS: Neither dissatisfied or satisfied, S:

Satisfied)

Conclusions

In general, the empirical results suggest:

The perceptions and beliefs of CET´s

concerning: subsidies, renewables energy prior

knowledge and environmental concern, play a

very important role in the decision-making

process of homeowners’ adoption for this type

of systems since they generate an impact on

the his/her emotional and cognitive side.

Therefore, these factors should be considered

to model the willingness of homeowner to

adopt sustainable energy technologies in

different countries.

The individual adoption behaviour of

technology is a universe that has many

elements to consider, such as the case of CETs.

Although the model used is sufficient to

represent the dependent variable, this could

be improved including other factors such as the

perceived behavioural control, the

environmental information sources, among

others.

Acknowledgments This study was conducted with the financial support received from the Spanish Ministry of Economy and Competitiveness [Research Project ECO2012–39576]. References Delafrooz, N., Taleghani, M., & Nouri, B. (2014). Effect of green marketing on consumer purchase behavior. QScience Connect, 1–9. https://doi.org/10.5339/connect.2014.5 Dieperink, C., Brand, I. and Vermeulen, W., 2004. Diffusion of energy‐saving innovations in industry and the built environment: Dutch studies as inputs for a more integrated

analytical framework, Energy Policy, 32: 773‐784. Frederiks, E. R., Stenner, K., & Hobman, E. V. (2015). The socio-demographic and psychological predictors of residential energy consumption: A comprehensive review. Energies, 8(1), 573–609. https://doi.org/10.3390/en8010573 Hosmer D W and Lemeshow S. (1980). A goodness-of-fit test for the multiple logistic regression model. Communications in Statistics, A10,1043–1069. Kaiser, F. G., Wolfing, S., & Fuhrer, U. (1999). Environmental attitude and ecological behaviour. Journal of Environmental Psychology, 19, 1–19. https://doi.org/10.1006/jevp.1998.0107 Laroche, M., Bergeron, J., & Barbaro-Forleo, G. (2001). Targeting consumers who are willing to pay more for environmentally friendly products. Journal of Consumer Marketing, 18(6), 503–520. https://doi.org/10.1108/EUM0000000006155 Mahapatra, K., & Gustavsson, L. (2007). Innovative approaches to domestic heating: homeowners’ perceptions and factors influencing their choice of heating system. International Journal of Consumer Studies, 0(0), 071203213649004-??? https://doi.org/10.1111/j.1470-6431.2007.00638.x Nagelkerke N J D. (1991). A note on a general definition of the coefficient of determination. Biometrika, 78, 691–692. Nyrud, A. Q., Roos, A., & Sande, J. B. (2008). Residential bioenergy heating: A study of consumer perceptions of improved woodstoves. Energy Policy, 36(8), 3159–3166. https://doi.org/10.1016/j.enpol.2008.04.019 Poortinga, W., Steg, L., & Vlek, C. (2004). Values, environmental concern, and environmental behavior: A study into household energy use. Environment and Behavior, 36(1), 70–93. https://doi.org/10.1177/0013916503251466 Rogers, E. (2003). Diffusion Of Innovations (The Free P). London, UK. Tilikidou, I. (2007). Pro-Environmental Purchasing Behaviour. Corporate Social Responsibility and Environmental Management, 14, 121–134. https://doi.org/10.1002/csr.123




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Tonglet, M., Phillips, P. S., & Bates, M. P. (2004). Determining the drivers for householder pro-environmental behaviour : waste minimisation compared to recycling. Resources, Conservation and Recycling, 42, 27–48. https://doi.org/10.1016/j.resconrec.2004.02.001 Van Rijnsoever, F. J., & Farla, J. C. M. (2014). Identifying and explaining public preferences for the attributes of energy technologies. Renewable and Sustainable Energy Reviews,

31, 71–82. https://doi.org/10.1016/j.rser.2013.11.048 Wesley-Schultz, P. (2001). The Structure of Environmental Concern : Concern for Self , Other People , and The Biosphere. Journal of Environmental Psychology, 21, 327–339. https://doi.org/10.1006/jevp.2001.0227 Young, F.W. (1981). Quantitative analysis of qualitative data Psychometrika, 46, 357.




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Construction and evaluation of a dry anaerobic digestion reactor for the degradation of solid waste from the textile industry with the use of fungal

keratinolytic strains Munive-Talavera, C1; Barreda-Del-Carpio, J1,*; Salamanca-Valdivia, M1; Cardenas-Herrera, L2; Garate-

Manrique, R3; Moscoso-Apaza, G3; Villanueva-Salas, J1

1Universidad Catolica de Santa Maria, Facultad de Ciencias Farmaceuticas, Bioquimicas y Biotecnologicas, Arequipa, Peru; 2Universidad Nacional de San Agustin, Facultad de Medicina, Arequipa, Peru; 3Instituto de Investigacion y Desarrollo para el Sur, Arequipa, Peru; *corresponding author email: [email protected] Abstract Twenty-three fungal strains were isolated from solid waste generated in the processing of alpaca and sheep wool from the company Inca Tops S. A. in Arequipa-Peru, as well as from cow rumen. Quantitative analyzes were carried out resulting in the selection of 5 microbial strains: Aspergillus sp., Fusarium oxysporum, Aspergillus sp., Fusarium oxysporum, and Fusarium sp. An experimental dry anaerobic digestion (DAD) reactor with 20L capacity was built, the configuration of which was made taking into account a one-stage batch system with feed recirculation and biomass ratio of 2:1 working at room temperature. Evaluation of the dry anaerobic digester was performed comparing the initial and final biomass after 60 days operation time, resulting in a decrease in the percentage of total solids from 37.91% to 28.82%, volatile solids percentage from 19.64% to 15.71%, chemical oxygen demand from 2 080.19 mg/Kg to 1414.63mg/Kg, and pH from 7.35 to 7.15. Keywords solid waste; dry anaerobic digestion; reactor; fungal strains; degradation capacity

Introduction Solid waste treatment has become a political priority in many countries. One of the main problems nowadays is to deal with an increasing amount of primary waste in an environmentally acceptable way. Solid waste production in Peru involves approximately 117.53 thousand tons of textile waste per year.

Solid waste requires a biological treatment that involves contact between microorganisms and the substrate, which in the present case is wastewater and biomass, along with isolated microorganisms with keratinolytic capacity present in the system. This has increased the interest to develop reactors to treat new substrates, resulting in different types of systems such as suspended growth reactors, fixed film reactors, or a combination of both (Bal, 2001).

When solid waste is treated it is usually carried out in wet conditions (raw material with a solids concentration between 0.5% and 15%), but it can also be carried out in dry conditions (raw material with solid concentration more than 20%) (Bolzonella, 2003).

The aim of this research is to construct a dry anaerobic digestion (DAD) reactor based on anaerobic digestion of organic matter from the Inca Tops textile corporation, through the use of anaerobic microorganisms with keratinolytic capacity for the degradation of the generated solid waste. In this way we seek to contribute to regional and national technological development.

Main body Dry anaerobic digestion reactor

mailto:[email protected]




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In order to design a bioreactor certain variables must be taken into account. For instance: high organic load, whether the reactor has reduced hydraulic retention times and if it has high methane production (Veeken, 1999).

Various types of configurations are used for this type of anaerobic digestion, such as single-stage or two-stage digesters; wet, dry and semi-dry digesters (Shah, 2015); batch or continuous digesters (Zhang, 2014), and high-rate digesters.

Anaerobic digestion is a natural process that occurs in anoxic environments found in nature, for example: manure, food processing residues, sediments, intestines of mammals (Ward, 2008).

Anaerobic reactors, better known as biodigesters, are generally used to treat concentrated substrates with high solids content. They can be classified, in the same way as aerobic reactors, in suspended biomass systems and in systems with fixed biomass (Tippayawong, 2010). Anaerobic processes have been applied successfully in the treatment of industrial waste, highlighting the feasibility of anaerobic reactors (El-Mashad, 2010).

Fungal strains in the treatment of biomass Fungi, particularly those that attack lignin, are used mainly in the preliminary treatment of lignocellulosic biomass for the production of biogas. Various kinds of fungi, including brown rot, white rot and fungal soft rot have been used for this preliminary treatment, being the variety of white rot the most effective through the action of lignin-degrading enzymes (Nielfa, 2015). Fiber structure Wool fiber consists of a complex mixture of approximately 170 different proteins. These vary in relative molecular mass from less than 10 000 Da to more than 50,000 Da. The basic structural units of proteins are amino acids. Intact wool contains 20 amino acids which have the general formula NH2CH (R) COOH, where (R) is the side chain of the amino acid. Methods

Solid waste sample collection from the processing of alpaca fiber and sheep wool. Solid waste samples derived from the processing of alpaca fiber and sheep wool were collected from the company Inca Tops S.A. in hermetic storage bags (7x9) duly labelled, and transported to the laboratory in a cooler in order to preserve the samples. Isolation and purification of fungal strains from textile solid waste. Sabouraud agar was prepared and then sterilized using the autoclave for 15 minutes at 120ºC and 1.5 atm. Subsequently, medium was distributed in 20 mL plates, after having solidified and being sealed the plates were taken to the incubator for 24 hours to check the harmlessness of the environment. 3.3. Isolation and purification of fungal strains obtained from cow's rumen.

Cow rumen was purchased and transported hermetically closed to the laboratory where it was opened and samples taken from the internal rumen folds. These were cultured in Sabouraud medium plates supplemented with gentamicin and chloramphenicol. The plates were preserved in an anaerobic jar for 15 days. Molecular identification of selected fungal species with degradation capacity. DNA of the native strains was isolated. The ITS gene sequences from the native strains, which were obtained by sequencing, were analyzed individually and compared with the sequences found in the GenBank database using the BLAST algorithm (www.ncbi.nlm.nih.gov/BLAST). Following this, phylogenetic trees were constructed to determine the genetic distances and percentage of similarity with other species. In addition, multiple alignment and phylogeny tests were performed with the CLUSTAL Omega program.

Design and construction of a DAD reactor for the biological treatment of textile solid waste.




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The DAD reactor was designed based on the behavior of the isolated strains and the study of industrial solid waste from the Inca Tops SA facilities, consisting of sheep wool and alpaca fiber residues as well as stubble (remains of stems, leaves, straws, soil, etc.).

The reactor was made up of 7 parts or elements, which were: vessel or container, outer jacket, headplate, gas accumulation system, biol accumulation system, influent recirculation system, and automatic temperature control system.

Results Fifteen strains were obtained from solid waste and 5 strains were obtained from cow rumen. Separately, 23 strains were analysed by the ninhidrine reaction, in which all the substances that have at least one amino group and one free carboxyl will react with ninhydrin. Figure 1 shows the ninhydrin test data for free amino groups performed at 40 days, in which it is appreciated that strains 1, 2, 3, 16 and 21 show the highest degradation percentage, compared with the other strains that have much lower values.

Figure 1. Biomass degradation at 40 days by quantification of free amino groups

Figure 2 presents the final configuration scheme of the DAD rector. This design shows 6 sections related to each other. Section A: Water heater tank 36 cm wide and 65 cm high with connections to the water pump and to the vessel’s jacket; section B: vessel connected to the sprinkler system and an outlet to the biol accumulation system; Section C: Vessel jacket 31 cm in diameter showing an inlet connection in the lower part coming from the water heater

tank and an outlet in the upper part connected to the water container; Section D: automated temperature control panel that activates the pump that supplies water into the water heater and empties water from the water container; section E: water container, 25 cm in diameter and 36.5 cm high, this presents an input connection from the jacket and an outlet connection connected to a pump; section F: biol container, presents an entrance that connects the outlet of the vessel to the biol container, and an outlet activated by level sensors that are connected to the pipes that carry the influent. All connections shown are 1/2 inch PVC pipe.

Figure 2. Design of the dry anaerobic digestion reactor, front view

Discussion Total solid content is an important factor to be taken into account since the increase in the concentration of this can limit or inhibit degradation by allowing or not a complete mobility of the fungal pool within the substrate, however it favours the development of biofilm on the substrate that, as reported by Di María (2017), would incite degradation and therefore gas production. In order to consider digestion to be dry, it should have a total solid content over 15% but not above 30% since this value represents a critical threshold over which performance is significantly reduced. Conclusions

Five strains with keratinolytic capacity for the

degradation of solid textile residues were

0

500

1000

1500

2000

1 3 5 7 9 11 13 15 17 19 21 23

Ab

s. 5

40

nm

Strains




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selected and molecularly characterized:

Aspergillus sp., Fusarium oxisporum,

Aspergillus sp., Fusarium oxisporum, and

Fusarium sp.

A reactor with 20 liters capacity and 11 L of

effective capacity was configured and

constructed with a one-stage batch system

with influent recirculation; influent and

biomass ratio of 2: 1 and mesophilic-like

temperature.

Biomass degradation was evaluated in the DAD reactor by comparing the initial and final biomass after 60 days working time, resulting in a decrease of total solids (T.S.) percentage, from 37.91% to 28.82%, volatile solids (V.S.) percentage from 19.64% to 15.71%, chemicaloxygen demand (COD) decrease from 2 080.19 mg/Kg to 1 414.63 mg/Kg. Decrease of these values demonstrates that biomass degradation is taking place since the degradation ratio and biomass content are directly proportional. Besides the pH value change from 7.35 to 7.15 guarantees good microorganism development and the correct operation of the reactors. Acknowledgments This research was supported by the project PITEI-3-P-343-105-15 Innovate Peru. References Bal, A. S., & Dhagat, N. N. (2001). Upflow anaerobic sludge blanket reactor a review. Indian journal of environmental health, 43(2), 1-82. Bolzonella D, Innocenti L, Pavan P, Traverso P, Cecchi F. Semi-dry thermophilic anaerobic digestion of the organic fraction of municipal

solid waste: focusing on the start-up phase. Bioresour Technol. 2003 Di Maria F, Barratta M, Bianconi F, Placidi P, Passeri D. Solid anaerobic digestion batch with liquid digestate recirculation and wet anaerobic digestion of organic waste: Comparison of system performances and identification of microbial guilds. Waste Manag. 1 de enero de 2017 El-Mashad HM, Zhang R. Biogas production from co-digestion of dairy manure and food waste. Bioresour Technol. 2010 Lorenzo Acosta, Y, Obaya Abreu, MC. La digestión anaerobia. Aspectos teóricos. Parte I. ICIDCA. Sobre los Derivados de la Caña de Azúcar [Internet]. 2005 Nielfa A, Cano R, Fdz-Polanco M. Theoretical methane production generated by the co-digestion of organic fraction municipal solid waste and biological sludge. Biotechnol Rep. 1 de marzo de 2015 Shah FA, Mahmood Q, Rashid N, Pervez A, Raja IA, Shah MM. Co-digestion, pretreatment and digester design for enhanced methanogenesis. Renew Sustain Energy Rev 2015 Tippayawong N, Thanompongchart P. Biogas quality upgrade by simultaneous removal of CO2 and H2S in a packed column reactor. Energy 2010 Veeken A, Hamelers B. Effect of temperature on hydrolysis rates of selected biowaste components. Bioresour Technol. 1 de septiembre de 1999 Ward AJ, Hobbs PJ, Holliman PJ, Jones DL. Optimisation of the anaerobic digestion of agricultural resources. BioresourTechnol. 1 de noviembre de 2008 Zhang C, Su H, Baeyens J, Tan T. Reviewing the

anaerobic digestion of food waste for biogas

production. Renew Sustain Energy Rev. 1 de

octubre de 2014;




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Full paper acknowledgment Full papers submitted for publication to journals or edited books should acknowledge the conference presentation: Acknowledgments The work has been presented at the 4th Renewable Energy Sources - Research and Business (RESRB) conference held on 8-9 July 2019 in Wrocław (Poland).

Citation format This publication may be cited as: Proceedings of the 4th Renewable Energy Sources - Research and Business RESRB 2019 conference, July 8-9, 2019, Wrocław, Poland.




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