the 4rd international conference on heating, ventilating

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The book of abstracts of

The 4rd International Conference on Heating, Ventilating and Air Conditioning

12-14 June 2012, Olympic Hotel Tehran-Iran

(400-word Abstracts)

www.hvac-conference.ir

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Organized by: Building and Housing Research Center Iranian Society of HVAC Engineers The Iranian Construction Engineering Organization The Iranian e-Community of Mechanical Engineers In partnership with: United Nations Environment Program (UNEP) Turkish Society of HVAC & Sanitary Engineers (TTMD) Pakistan HVAC&R Society

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In Cooperation with: Institute of Standard and industrial Research of Iran The Iranian Society of Consulting Engineers The Iranian Syndicate of M&E and Industrial Contractors The Iranian Combustion Institute National Iranian Gas Company Safe Communities Association Sponsored by: Iran Radiator Industrial Group Butane Industrial Group LG Air Conditioning

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Iran Industrial Vibrations Co. Tabadol Kar Co. Tehran Construction Engineering Organization Iran Energy Efficiency Organization Media Sponsors: Air Conditiong Magazine Tose’e Magazine

ecasb web portal Event manager: Aria Group

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Scientific Committee:

Prof. Abbas Abbasi (Amirkabir University of Technology – Iran) Mr. Ayub Adeli (Iranian Combustion Institute) Dr. Cyrus Aghanajafi (K N Toosi University – Iran) Dr. Abolfazl Ahmadi (Iranian University of Science and Technology – Iran) Prof. Mohammad A. Akhavan (University of Tehran – Iran) Dr. Ali Akbar Alam Rajabi (Esfahan University of Technology-Iran) Dr. Majid Amidpour (K N Toosi University – Iran) Dr. Mohammad Reza Ansari (Tarbiat Modares University – Iran) Prof. Mahmoud Arab Yaghoubi (University of Shiraz – Iran) Prof. Mehdi Ashjaei (University of Tehran – Iran) Prof. Mehdi Bahadorinejad (Sharif University of Technology – Iran) Dr. Farzad Bazdidi Tehrani (Iranian University of Science and Technology – Iran) Dr. Mehdi Bidabadi (Iranian University of Science and Technology – Iran) Dr. Shahram Delfani (Building and Housing research Center – Iran) Mrs. Parichehr Ghezelbash (The Institute of Standards & Industrial Research of Iran) Mr. Asghar Haj Saghati (Iranian Solar Energy Society) Prof. Ghassem Heidarinejad (Tarbiat Modares University – Iran) Dr. Mostafa Hosseinalipour (Iranian University of Science and Technology – Iran) Prof. Mohammad Hosni (Kansas State University – USA) Dr. Mansour Jadidi (Shahid Rajai University – Iran) Dr. Ali Jafarian Dehkordi (Tarbiat Modares University – Iran) Dr. Vali Kalantar (Yazd University-Iran) Mr. Babak Kamkari (University of Tehran-Iran) Dr. Farzad Jafarkazemi (Islamic Azad University – Iran) Dr. Abdol Razagh Kabinejadian (Iranian Society of HVAC Engineers -Iran) Dr. Hossein Khorasanizadeh (Kashan University-Iran) Prof. Farshad Kosari (University of Tehran-Iran) Dr. Mostafa Mafi (University of Qazvin-Iran) Dr. Mehdi Maerefat (Tarbiat Modares University – Iran) Prof. Kiumars Mazaheri (Tarbiat Modares University – Iran) Prof. Mozafar Ali Mehrabian (Bahonar University of Kerman – Iran) Mr. Mohammad Mirzaei (Iranian Fuel Conservation Company) Prof. Mohamamd Moghiman (Ferdowsi University of Mashad – Iran) Mr. Heshamatolah Monsef (Piraz Consultants Co. – Iran) Mr. Manuchehr Motamedi (Jarvand Co. - Iran) Prof. Mojtaba Mousavi Nainian (K N Toosi University – Iran) Mr. Ali Norouzimanesh (Iranian Fuel Conservation Company) Dr. Amir Omidvar (Shiraz University of Technology-Iran) Mr. Hadi Pasdarshahri (Tarbiat Modares University – Iran)

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Dr. Majid Sabzpoushani (Kashan University-Iran) Prof. Majid Saffar Aval (Amirkabir University of Technology – Iran) Prof. M. H. Saidi (Sharif University of Technology – Iran) Dr. Sorena Sattari (Sharif University of Technology – Iran) Dr. Mohammad Behashd Shafie (Sharif University of Technology – Iran) Dr. Ghanbar Ali Sheykhzadeh (Kashan University-Iran) Dr. Asghar Shirazpour (Iranian Construction Engineering Organization – Iran) Prof. Hossein Shokouhmand (University of Tehran – Iran) Dr. Alireza Zolfaghari (Bojnourd University) Dr. Saeid Zeinali Heris (University of Mashad)

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Abstract Index

Title Page

A new sky temperature calculating method used for designing the nocturnal cooling systems 3

Under-Floor Heating Systems: Computational prediction of Optimum Convection Heat Transfer Coefficient

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Analyzing the possibility of increasing air speed in double skin façade to prevent over heating 6

The study of flow in a common chimney for multi-storey buildings 7

Experimental Study of Combined Convection and Radiation from a Radiator into a Heating Enclosure 8

Experimental investigation of natural convection heat transfer of Turbine oil in a square enclosure 9

Optimization of a Solar Double-Effect Absorption Chiller Using Multi-objective Genetic Algorithm 10

Experimental investigation on heat transfer and pressure drop enhancement in laminar and low Reynolds numbers turbulent flow regimes inside horizontal coiled wire inserted tubes

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Investigation of the role of contaminant source location on removal efficiency and inhaled air quality for a room with stratum ventilation

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An Experimental Investigation on the Effect of Density and length of Longitudinal Flexible Filaments on Heat Transfer and Pressure Drop in the Internal Flow

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Development of an intelligent method for determining temperature setpoint trajectories for Sharif Energy Research Institute

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Adaptive optimal control of a VRF system by using fuzzy logic and utilizing genetic algorithm for optimization of controller’s gains

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Study of air infiltration through straight crack 16

A review on Control systems for energy management and provide comfort in the buildings 17

Experimental and semi-analytical study on natural ventilation performance of different geometry of one-sided wind catchers

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Behavioral comparison between the single and the multi pressure traditional wind catchers caused by variations in outdoor wind directions

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Analyzing the impact of openings’ number and outdoor flow direction on the indoor vertical flow velocity in traditional wind catchers’ channels

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A Review on Chapters 17 and 19 of the National Regulations on Buildings,Emphasis on Fresh Air and Air Combustion for Gas Feeding Systems

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Ventilation Network Design for Stope 3 Mine 1 Parvadeh Tabas 27

Experimental Analysis of Aircraft Individual Air Distribution System Design 28

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Design Of Ventilation System For The Niayesh Roadway tunnel 29

Criteria of Effectiveness Evaluation of centrifugal pumps in district heating systems 30

Energy and Exergy Analysis of Different Cogeneration Heat and Power Systems in buildings 33

Numerical study of the effects of water-Al2O3 nanofluid on underfloor heating system 34

Thermodynamic Analysis of Combined Power and Refrigeration Cycle with HCCI Engine Prime Mover 35

Modeling of Micro Combined Heat and Power Systems (MCHP) for Residential Applications Using the Gas Internal Combustion Engine

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An Empirical Study on the Effects of Horizontal Corrugated Tubes on Heat Transfer and Pressure Drop of Nanofluid Flows

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Experimental Investigation on Heat Transfer of Nanofluid Laminar Flow in U-bend tubes with different bend radiuses

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Applications of phase change materials in air conditioning and methods of heat transfer enhancement: A Review

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Augmentation of heat transfer of MWCNT/heat transfer oil nanofluid laminar flow Inside helically coiled tubes 40

Applications of phase change materials in air conditioning and methods of heat transfer enhancement: A Review 41

Design combined cooling, heating and power system for residential building in hot climates in Iran 42

Experimental Approach to Enhance Solar Water Heater using Phase Change Materials 43

The Trials and Tribulations of Creating an HFC/HCFC Free Food Processing Plant by Installing a Two Stage Transcritical CO2 Refrigeration Plant

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The Energy Efficiency in Office Buildings and Hospitals Using Total Energy NH3 and CO2 Systems Separately and Combined for Heating and Cooling

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Optimization In Nitrogen Liquefier With Mixed Refrigerant 49 Investigation of leaked air into cycle and its purging effects on air cooling chiller cycle of cryogenic nitrogen generation unit

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Elevation analysis of potential requirements for heating and cooling from viewpoint of climate according to humidity & temperature

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Three Dimensional Modeling of Laminar Air Flow Conditioning System with Air Curtain in Surgery Room

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Experimental Study of Thermal Comfort of an Automobile Driver’s Hands with Ventilated Steering Wheel 55

Investigation of the role of outlet position and sitting location on thermal comfort and inhaled air quality for a room with stratum ventilation

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Novel Energy Demand Side Management Practices and Cooling Load Reduction in Office Buildings Case Study: National Iranian Drilling Company New Building Complex

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Experimental Investigation of Resulted Energy Saving in an Hybrid Air Conditioning System, Using of Desiccant Filter and Heat Pipe Heat Exchangers in Series

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The effectiveness of Intelligent Controlling Chilling System and Controlling System of Radio Frequency of Fan Coil in optimization of electric energy consumption and separation of time from the load of electric network in peak time of consumption

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Methodologies for Optimization the Energy Consumption in Design and Construction Process and Experimental test in the Sample Building

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Three-dimensional simulation of cooling system using solar chimney and underground wet channels 65

Theoretical & Experimental Analysis of a Flat Plate Solar Collector 66

Design and Simulation of Solar Assisted Single Effect Absorption Chiller For Tehran 67

Simulation And Exergy Analysis Of Solar Lithium Bromide Single Effect Absorption Chiller 68

Exergy Analysis of GSHP with Low Temperature Source 69

Exergy analysis of a solar ejector refrigeration system during a day 70

Analytical and numerical investigation of influence of the absorber plate position in a solar chimney 71

Experimental Study on Compatibility of Heating Application of Geothermal energy in Ardabil City 72

Parametric study of an indirect solid oxide fuel cell-gas turbine hybrid system performance from exergy viewpoint

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3D Numerical simulation of a flat plate solar collector and investigation of effective parameters on collector operation in dry climate

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Transient simulation of a solar stratified storage tank for using in solar cooling system 75

Design of a solar cooling system based on Adsorption for an office building in Tehran 76

Financial analysis of using a solar cooling system based on Adsorption for an office building in Tehran 77

Modeling the Performance of a Solar Heat Pump and Comparison with Conventional Heat Pumps 78

Performance Analysis of a solar Li-Br absorption systems 79

Integration of Ground and Capillary Heat Exchangers for Cooling Greenhouse Food Production in Areas around the Persian Gulf

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Technical and economical analysis of using solar energy in North Khorasan gas company’s buildings 81

Refrigerant Inventory Prediction in Refrigeration Equipment 85

Effect of pollutions on the performance of Squirrel cage fan of the kitchen hood and introducing the DOSG filter

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Software Preparation of Mechanical Design of Fire Tube Boilers 87

Increasing Outlet Temperature of Radiation Super Heater at Wet Back Fired Tube Boilers 88

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The 4th International Conference on

Heating, Ventilating and Air conditioning

New Design Criteria in HVAC&R

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A New Sky Temperature Calculating Method Used For Designing the Nocturnal Cooling Systems

Maryam Karami1, Moien Farmahini-Farahani2, Shahram Delfani3

1Department of Mechanical Engineering, Faculty of Engineering, University of Tehran, [email protected]

2School of Aerospace and Mechanical Engineering, University of Oklahoma, USA. 3Department of Installation, Building and Housing Research Center (BHRC), Tehran, Iran.

ABSTRACT

he sky temperature affects performance of solar heating and nocturnal cooling systems. Nocturnal cooling systems are categorized in Passive cooling system. Passive cooling resources, the sky,

atmosphere, and earth, are the natural heat sinks of the planet earth. The dissipation of heat carried out by long-wave radiation from a building to the sky that is called radiative cooling. In this system, the water in a storage tank is cooled by means of circulating the water through a flat-plate radiator throughout a night (nocturnal radiative cooling). During the next day, the cold water in the storage tank is used for cooling the hot outdoor air. This system can be also used as a hybrid system with direct evaporative cooling. Since sky temperature is a function of the ambient temperature, it is obvious using climatic design conditions result in more accurate sky temperature calculations, leading to estimate the potential of the nocturnal cooling more precisely. In this study, the Bin method has been used to analysis climatic data and reach design values that occur more frequently. This method is the most important steady-state model used to calculate the design condition. In order to analysis by this method, bin weather data should be evaluated with long-term measured data. Hourly DBT and WBT from the Islamic republic of Iran Meteorological Organization (IRIMO) were used for the calculation of design conditions. Bin data for dry-bulb and wet-bulb temperatures were calculated in eight daily three-hour shifts (1–3, 4–6, 7–9, 10–12, 13–15, 15–17, 18-21, 22-24 h) for the important cities of Iran showed in Figure 1. The most cities are capital of 30 states of Iran. Using bin method causes the outdoor design condition and sky temperatures are evaluated more accurately. Then the difference of the ambient and sky temperature, sky temperature depression can be determined precisely. These are used in solar heating and nocturnal cooling in urban buildings. In this research, at first, the new climatic design conditions were calculated for important cities of Iran; then these new dry-bulb (DBT) and wet-bulb temperatures (WBT) were used to calculate the sky temperature. Then, monthly clear sky temperature contours of a multi-climate country, Iran, have been depicted. As the results, Iran cities based on the local clear sky temperature variation are categorized in four regions

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Study of Heat Transfer in Phase Change Materials (PCM) and Its Application in Cooling, Heating and Air Conditioning Equipment Using Network/Boltzmann Method

Arman Marufi1, Cyrus Aghanajafi2

1Faculty Of Mechanical Engineering K.N.Toosi University Of Technology; [email protected]

2Associate Professor, Faculty of Mechanical Engineering K.N.Toosi University of Technology; [email protected]

ABSTRACT

owadays, using fossil energy causes global warming, melting polar ice caps, and occurrence of destructive hurricanes, which is jeopardizing human beings life. In addition, because of the

increasing demand of energy, and decreasing of fossil fuels sources, using renewable source of energy has become inevitable. One of these sources is using the latent heat capacity during phase change processes. In phase change materials (PCMs) the mentioned fact is the basic principle of energy storage. Because of huge amount of energy which stored in this way, PCM's have many applications in electronics, telecommunications, aerospace, thermal systems, commercial and residential buildings. PCM phase change temperature according to the temperature, PCM’s divided into three groups of hydrated salts, organic materials and eutectics. PCM’s which their melting temperature are below 15°C are used for cooling and air conditioning. Using this technology, especially for cooling of Canada and America houses in summer, is saving 50 percent of energy consumption. This transfers electrical energy consumption from high-load hours into low-load hours which lead to a great amount of financial saving. This paper investigates the heat transfer in phase change materials and their usage in heating, cooling and energy saving processes. We used Lattice Boltzmann Method (LBM) in this paper. LBM is of the new techniques which has many applications in Computational Fluid Dynamics. It can simulate heat transfer problems with complex geometries quickly and precisely .We used D2Q9 Lattices. To calculate the particle collisions, the BGK approximation is used and the Temperature distribution, and the interface location and speed have been studied.

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Under-Floor Heating Systems: Computational Prediction of Optimum Convection Heat Transfer Coefficient

Amin Engarnevis1, Hadi Jafari2, Majid Amidpour3

1,2Faculty of Mechanical Engineering, KNT University of Technology;

[email protected], [email protected] 3Energy systems Engineering Department, Faculty of Mechanical Engineering, KNT University of Technology;

[email protected]

ABSTRACT

n this study, in a floor heated room, optimum natural convection heat transfer over the floor is analyzed numerically for constant specific conditions such as; Temperature of supply water, design

temperature, outside temperature, thickness of concrete on water tubes, distance among water tubes and, etc. In this condition, an optimum heat transfer coefficient of air always exists for which maximum heat transfer from the floor takes place. In this paper, above parameters are introduced and the effect of thickness of concrete on heat transfer is investigated. Subsequently, the effect of different amounts of convection heat transfer coefficient of moving ambient air on the obtained heat transfer from the surface of the concrete is studied. Results showed that thickness of concrete has a great effect on fluxes of energy obtained from the coverage, ex. marble. And by using less thickness of concrete, more fluxes of energy is obtained. Also, consequences are noted that by different amounts of mentioned parameter, various amounts of thermal energy from the surface of the concrete are available. This optimum convection heat transfer coefficient can be obtained through an electrical fan to get a more economical thermal power from the surface. Keywords: Under-Floor Heating, Wirsbo Model, Optimum Convection Heat Transfer Coefficient Industrial/Professional Applications • Results of the paper can be applied for designing optimum under-floor heating systems. • Results are shown if concrete be used as coverage on water tube, with increasing thickness and distance of tubes, heat flux in floor increases and reduces respectively. This note can be applied in installation and design of these systems and using various overages can be studied. • Utilization Electric fan can be useful to reach optimum heat transfer coefficient of room air. • Using Wirsbo Model because considering symmetric line as adiabatic boundary conditions makes it easier analyzing under-floor heating systems.

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Analyzing the Possibility of Increasing Air Speed in Double Skin Façade to Prevent Over Heating

Majid Salehi1, Nazanin Nasrollahi2, Jamal Khodakarami3, Jafar Mamizade4

1M.A.Student of Architecture, Ilam University; [email protected] 2Department of Architecture, Ilam University; [email protected] 3Department of Architecture, Ilam University; [email protected]

4Department of Water Engineering, Ilam University; [email protected]

ABSTRACT

uildings’ shell spaces act as a separator between the inside and outside. It plays an effective role in reducing energy consumption while creating an efficient shield of thermal wall in buildings

alongside a sustainable technology in order to minimize the disposal of heat in winter as well as gain of heat in summer. The double-skin facades designs are the suitable solution as a strategy for achieving the thermal savings mindset. In addition to increasing the thermal and visual comfort of the designs, energy consumption is also significantly reduced as a result. This strategy is not considerably efficient for hot and dry climates as the temperature of the cavity between the shells increases. Using CFD simulation process, this paper aims to improve DSF application for overheating condition in the cavity between two layers in the shell. The simulation results show that if DSF placed windward, the bottom openings play an effective role to increase air speed in the cavity. Keywords: Double skin facades, CFD, Hot and dry climate, Thermal comfort.

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The Study of Flow in A Common Chimney For Multi-Storey Buildings

M. Rahimi1, J.K. Kaleji2, H. Azad3

1Associate Professor, University of Mohaghegh Ardabili; [email protected] 2Msc Student, University of Mohaghegh Ardabili; [email protected]

3Msc Student, University of Mohaghegh Ardabili; [email protected]

ABSTRACT

pplication of gas heaters has been developed in our country for residential and official buildings due to its simplicity and other advantages. In multi floor buildings, using of separate chimneys

gives rise to some practical difficulties, while using a common chimney with reliable exclusivity the problems could be retrieved. In this study, a cubical cavity was designed and made to measure the air flow rate passing through a gas heater installing the heater within the cavity. The results of a preliminary test indicated that the cavity had a negligible effect on the air flow rate passing through the heater but a significant effect on the heat transferred from the heater to the surroundings. In the next step, this cavity was used for testing in a model of a two floor building with two identical gas heaters each installed in a floor. The flue of gas heaters was directed into a common chimney having about 6 m length and 10, 12 and 15 cm diameter. Based on the results, the air flow passing through each heater increased as the length and diameter of the chimney above the heater were enlarged. The pressure inside the common chimney decreased on the vertical direction approaching to the surrounding pressure at the exit section. Among the tested diameters, the combustion products from two heaters were efficiently discharged using the common chimney of 15 cm diameter, while the common chimney of 10 cm diameter was not sufficient for discharging the flue satisfactorily. Keywords: Gas heater, common chimney

Industrial/Professional Applications The air flow passing through each heater increases as the length and diameter of the chimney above the heater are enlarged The pressure inside the common chimney decreases on the vertical direction approaching to the surrounding pressure at the exit section. The common chimney of 10 cm diameter is not sufficient even for discharging the flue gases of two small gas heaters.

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Experimental Study of Combined Convection and Radiation from a Radiator into a Heating Enclosure

M. Rahimi1, H. azad2, A. Najafzadeh Khosroshahi3

1Associate Professor, University of Mohaghegh Ardabili; [email protected]

2Msc Student, University of Mohaghegh Ardabili; [email protected] 3Msc ; [email protected]

ABSTRACT

ree convection and Radiation contribution in heat transferred from external surfaces of a radiator to the internal surfaces of an enclosure has been investigated at the present study. A common

radiator was installed within an enclosure located at a large test room. Several surface elements were specified on both internal and external surfaces of the enclosure and also on the external surfaces of the radiator. Under steady state condition, temperature distribution was measured using an infrared thermometer on both sides of the enclosure sidewalls, the ceiling and the external surfaces of the radiator. Also temperature was measured at eight points of the upper and lower surfaces of a plywood sheet located under the floor surfacing. Other data including the voltage and current passing through the electrical resistor of the radiator, surrounding temperature and temperature distribution inside the enclosure were also measured and recorded using a data acquisition system. Heat conduction rate through the elements considered on the sidewalls and the ceiling was calculated using temperature distribution on both sides of the compartments. Heat loss rate from the floor was also calculated assuming one-dimensional heat conduction through the plywood sheet. Heat transfer rate by radiation among all the elements specified on the internal surfaces of the enclosure and the external surfaces of the radiator was calculated using net radiation method. Being specified conductive and radiative heat transfer rate for each surface element, convective heat transfer rate of the element was also calculated. Based on the results, only about 1/3 of the heat is transferred by radiation from the radiator into the enclosure internal surfaces and the output heat rate of the radiator has a negligible influence on this contribution. Meanwhile, radiation is the predominant mechanism in heat transferred to the floor but convection to the ceiling of the enclosure. Keywords: Radiator, Heating, combined convection and radiation

Industrial/Professional Applications Heat is mainly transferred by radiation from a radiator to the floor of a heating space. Heat transfer from a radiator to the ceiling of a heating space is mainly accomplished by convection. Contribution of the radiation in heat transferred from a radiator to the internal surfaces of an enclosure is only about 1/3.

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Experimental Investigation of Natural Convection Heat Transfer of Turbine Oil in A Square Enclosure

M. Borhanipour1, S. Zeinali Heris2, S.H. Noie Baghban3

1Msc student of Chemical Engineering, Ferdowsi University of Mashhad; [email protected]

2Assistant Professor, Department of Chemical Engineering, Ferdowsi University of Mashhad; [email protected]

3Professor, Department of Chemical Engineering, Ferdowsi University of Mashhad; [email protected]

ABSTRACT

atural convection has an important role in many engineering applications and naturally occurring processes, such as energy conservation and energy efficient design in building, home heating and

cooling, cooling of heat source, electronic components, and cooling systems. This paper reports an experimental study on the natural convection heat transfer of turbine oil in a square enclosure with dimensions, length × width × height (cm), 10 × 10 × 10. One of the walls is cooled at a constant temperature bath (water) and the opposite wall of that is heated by a constant flux heat source, while the remaining walls of the enclosure is adiabatic. The cooled and heated walls were located vertically and horizontally each time and then compared their natural convection heat transfer coefficient. The results are presented in terms of the Nusselt number as a function of Rayleigh numbers. Over the entire range of the Rayleigh number, natural convection heat transfer coefficient and Nusselt number, increased and where the cooled and heated walls are horizontal, especially at low Ra, are higher than the vertically walls, about 15 percentage. At low Ra, conduction is dominant heat transfer mechanism inside the enclosure. With increasing Rayleigh number, movement of the fluid inside the enclosure increases. The higher Ra lead to entrance more heat, and as a result, more heat is added to the fluid, increases the fluid convection. The natural convective heat transfer coefficient depends not only on the thermo physical properties of the fluid and geometry under study, but also on other factors such as method of heating, configuration and orientation of the heater, and the properties of the heating and cooling surfaces. As a Conclusion locating the cooled and heated walls horizontally, can save energy and time. That is in agreement with the previously published work. For these two states, temperature distribution and Local Nusselt number versus distance from hot wall are plotted. Volumetric thermal expansion coefficient of turbine oil at the different temperature has determined too. The thermal expansion characteristic is one of physical property, which plays an important role in many heat removal systems involving natural convection. Keywords: natural convection heat transfer, Turbine oil, square enclosure, volumetric thermal expansion coefficient Industrial/Professional Applications The mentioned approach in this manuscript will be increase efficiency in the cooling systems. Results of this study can be applied in the cooling system of turbine, for 15% energy and time saving. The mentioned approach in this study can be used in the industrial units for cooling of heat source, electronic components and cooling systems.

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Optimization of a Solar Double-Effect Absorption Chiller Using Multi-objective Genetic Algorithm

A. Iranmanesh1, M. A. Mehrabian 2, M. Salmanzadeh 3

1Master of Science, Shahid Bahoner University of Kerman; [email protected]

2Professor, Shahid Bahoner University of Kerman; [email protected] 3Assistant Professor, Shahid Bahoner University of Kerman; [email protected]

ABSTRACT

owadays due to increase in energy consumption, high price of fuel, and depleting the ozone layer, absorption chillers are of more interest. Unlike the compression chillers, the input energy to the

absorption chillers is in the form of heat. As a result, solar energy, energy discharged from industrial processes, and geothermal energy can be applied in absorption chillers. In this research, sensitivity analysis is carried out for a double-effect absorption chiller with 100 tons of cooling capacity. The input parameters namely the volume of storage tank, the area of evacuated tube collector, and the mass flow rates of water passing through the collector and generator are optimized using genetic algorithm. The evacuated tube collector is arranged at the optimum angle to get the highest solar radiation. To obtain the optimum value of the collector area, an economical analysis is required. The following assumptions are made to complete the optimization process: 1. Steady-state conditions apply. 2. Pressure and energy losses are ignored (except for the storage tank). 3. The expansion valves are adiabatic. 4. The refrigerant leaving the condenser is at the state of saturated liquid. 5. The refrigerant leaving the evaporator is at the state of saturated steam. 6. The refrigerant leaving the generator is at the state of superheated steam. 7. The effectiveness of solution heat exchangers is considered constant. 8. The solutions leaving generators and the absorber are at the state of saturated liquid. The storage tank is simulated using the stratification method. In this method, the storage tank is divided into three nodes and temperature in each node at the next step is evaluated by solving three simultaneous differential equations. The fourth order Runge-kutta method is used to accomplish this objective. The results obtained in this research are listed below: 1. Selection of each point on the Pareto chart depends on initial costs and investment return period. 2. The efficiency of the evacuated tube collector becomes maximum when the solar radiation intensity is maximum. 3. The optimum amounts of mass flow rates of hot water passing through the generator and collector have an important role in reducing the required energy. 4. The solution has the same concentration at the outlet of absorber, and the inlet of high-pressure pump. 5. The solution has the same concentration at the outlet of high-pressure generator, and the inlet of low-pressure heat exchanger. Keywords: Absorption Chiller, Evacuated Tube Collector, Genetic Algorithm, H2O-LiBr,Optimization

Industrial/Professional Applications

The results obtained in this research can be applied to the industrial HVAC systems. The optimum values of mass flow rates of water passing through the collector and generator can reduce the amount of auxiliary energy dramatically. Since the auxiliary source provides input heat to the generator most of the time, utilizing a double-effect absorption chiller without auxiliary source will be impractical. Using an evacuated tube collector can be very effective in reducing the rate of energy consumption.

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Experimental Investigation On Heat Transfer And Pressure Drop Enhancement In Laminar And Low Reynolds Numbers Turbulent Flow Regimes Inside Horizontal

Coiled Wire Inserted Tubes

Ali Akbar Shamshiri1, Mohammad Ali Akhavan2, Ahmad Sedaghat3

1 School of Mechanical Engineering, Graduated M.Sc, Isfahan University Technology , Isfahan, Iran; [email protected]

2School of Mechanical Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran; [email protected]

3School of Mechanical Engineering, Faculty of Engineering, Isfahan University Technology, Isfahan, Iran; [email protected]

ABSTRACT

n this work, an experimental study is carried out to investigate the pressure drop and heat transfer enhancement by means of a smooth tube with wire coils inserted in laminar, transition and low

Reynolds numbers turbulent flow regimes. Wire coils show several advantages in relation to other enhancement techniques such as Low cost and Easy installation and removal. By using heat transfer oil HT-B as the test fluid at different temperatures and flow rates, a wide range of flow conditions have been covered: Reynolds numbers from 100 to 4300 and Prandtl numbers from 150 to 430. The wall temperature was maintained constant throughout this study and to provide constant wall temperature, the entire test section is surrounded by saturated water vapor. The fluid flow in the tubes is considered hydrodynamically developed, but thermally is in developing stage. The experimental study was carried out on six test sections including a circular tube with 1500 mm length, 14.5 mm inner diameter and 15.6 mm outer diameter and five wire coils fitted in the plain tube that made of carbon steel, within a geometrical range of helical pitch 1.12 < p/d < 2.79 and wire diameter 0.069 < e/d < 0.097. The smooth tube results have shown a good agreement with the available data. Wire coils inserted friction factor experimental results showed that in the fully laminar region, at Reynolds numbers below 400, the friction factor increases lie between 18% and 80%. When Reynolds number exceeds 400, friction factor stays close to a constant value that depends to geometry of wire coils and for Reynolds number above 2000 reduces again. The transition from laminar flow to turbulent flow is continuous, without the instabilities and the pressure drop fluctuations that a smooth tube presents and in this region. Heat transfer experimental data at Reynolds number below 400 illustrated that wire coils enhanced heat transfer up to only 25%. For Reynolds numbers between 400 and 2000, wire coils remarkably increase heat transfer. At Reynolds numbers above Re = 900–1200, transition from laminar to turbulent flow takes place. At Reynolds number around 2000, wire inserts increase the heat transfer coefficient up to six times with respect to the smooth tube. The performance evaluation applied to estimate the heat transfer enhancement and pressure drop increase simultaneously. The results showed that heat transfer rate can be increased up to 280% keeping pumping power constant. Keywords: heat transfer, pressure drop, constant temperature and wire coil inserts.

Industrial/Professional Applications Wire coils can be used when it is required to increase the heat transfer rate of an existing heat exchanger. By using wire coils heat transfer rate can be increased up to 280% keeping pumping power constant. Wire coils reinforce strength of tubes.

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Investigation of the Role of Contaminant Source Location on Removal Efficiency and Inhaled Air Quality for a Room with Stratum Ventilation

G.R. Molaeimanesh1

1 Ph.D. Candidate, Mechanical Engineering School, Shiraz University

ABSTRACT

tratum ventilation is a new ventilation method which can assist reducing energy consumption and also result in cost saving. In fact applying stratum ventilation method is the main option for

reducing energy consumption of ventilation systems in near future. In this method, ventilation of only a stratum of indoor space in which occupants’ head and chest is located is pursued. This is realized by positioning supply terminal(s) at the side-walls or columns slightly above the height of occupants. Although the supply air temperature for stratum ventilation is higher than that of conventional ventilations, the distance between the occupants and the air terminal is shorter, which results in reverse temperature gradient in the occupied zone, higher air speed for the same air supply rate, energy saving by avoiding over-cooling of the lower zone of a room and higher coefficient of performance (COP) for the associated refrigerating plant. In this study 48 stratum ventilated cases with a manikin sited behind a desk and with different contaminant Source locations and outlet positions are numerically modeled. Two evaluation indexes are computed for each case to investigate the effects of contaminant source locations and outlet position on contaminant removal efficiency and inhaled air quality. The results show the great influence of source location and outlet position. In fact selecting outlet position is greatly dependent on source location. When the source is located behind the manikin it would be better to position outlet at the left wall near source location. Also when the source is located at higher elevations, it would be better to position outlet at the ceiling. Keywords: Stratum ventilation, contaminant removal efficiency, inhaled air quality, contaminant source location, outlet position.

Industrial/Professional Applications Applying stratum ventilation method is the main option for reducing energy consumption of ventilation systems in near future. It has been demonstrated that stratum ventilation is able to provide good indoor air quality in breathing zone and to achieve good thermal comfort measured by PDD and PMV. The results of this study show that when the contaminant source is located in the inlet jet domain the inhaled air quality will be the worst. When the source is located behind the manikin, it would be better to position outlet at the left wall near source location. When the source is located at higher elevations, it would be better to position outlet at the ceiling.

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An Experimental Investigation on the Effect of Density and length of Longitudinal Flexible Filaments on Heat Transfer and Pressure Drop in the Internal Flow

Omid Nematollahi1, S. Amin Feghhi2, Ali Akbar Alemrajabi3, Mahdi Nili AhmadAbadi4

1M.S. Student, Mech. Eng. Dept, Isfahan University of Technology; [email protected]

2PhD Candidate, Mech. Eng. Dept, Isfahan University of Technology; [email protected] 3Associate Professor, Mech. Eng. Dept, Isfahan University of Technology; [email protected] 4Assistant Professor, Mech. Eng. Dept, Isfahan University of Technology; [email protected]

ABSTRACT

eat transfer enhancement has been widely used in recent years. Heat exchangers with enhanced heat transfer work at a lower velocity or reduced driving force temperature and/or smaller size.

Many ways exist to achieve these goals. In this study, the effect of flexible filaments on enhancement of heat transfer and pressure drop is investigated. Also a Performance Evaluation Criterion has been defined and applied to evaluate the economic benefit of these filaments. In this study, the effect of Density and length of filaments on heat transfer and pressure drop in a tube of uniform wall temperature is investigated. The range of Reynolds number for turbulent flow is from 3000 to 10000. The results of our experimental tests have shown that use of these flexible filaments leads to enhanced heat transfer and pressure drop, whose extents depend on the type of filament, array type and length of filament in the tube. It was found that filaments with higher density have greater effect on heat transfer and pressure drop. Also, filaments of shorter length are more effective. Furthermore, in turbulent flow, the Nusselt number increases by 46%. The Performance Evaluation Criterion (P.E.C) of 0.61 was achieved. Keywords: Internal flow, Flexible filaments, enhancement of heat transfer, Inserts.

Industrial/Professional Applications Results of the article can be applied for heat transfer enhancement in the heat exchangers. With using mentioned method, lower pressure drop can be achieved. The best Performance Evaluation Criterion (P.E.C) of 0.61 was achieved. That showing this method is beneficial.

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Development of an Intelligent Method for Determining Temperature Setpoint Trajectories for Sharif Energy Research Institute

Amin Joudzadeh1, Abbas Rajabi Ghahnavieh2

1M.Sc. student, Sharif University of Technology; [email protected]

2Faculty member, Sharif University of Technology; [email protected]

ABSTRACT

ue to the significant portion that buildings possess in total energy consumption, aside from the government’s attempts to reduce the consumption peaks by taking up on strategies such as

increasing the fees in the peak hours, highlights the importance of consumption management in this section. Economic gains of this method have been boosted within the increase of energy carriers after the so-called “Economic Transition” bill came to be realized. A quick look at the energy consumption statistics of Iran, allocates a portion of 35 percentages to the building section amongst all the others. Regarding the Heating and Ventilation section to take up 15 to 20% of the total consumption of the buildings, the prominence of a Building Management System with focus on this section is evident. Focusing the researches to this field could result in brand new conservatory methods for the buildings, efficacious around the clock as well as in the peak hours. Therefore, this work deals with the development of a control algorithm to determine the optimal indoor temperature setpoint, with respect to varying energy carrier fees. The objective of the optimization through the developed algorithm is to minimize the energy consumption costs, in the heating and ventilation section. After providing a parametric model for the problem, required quantities based on a typical setup in the Sharif Energy Research Institute Building, were fed to the model. By solving the problem with different conditions, a database was built from the results, which in turn was utilized to train an Artificial Neural Network. The BMS algorithm was enhanced to be capable of online performance and pattern recognition through the implementation of the available database and the trained ANN. What could be observed in the results was a clearly visible reduction in the daily energy consumption, manifesting itself as an approximate 10% decrease in the energy costs in the warm seasons, as well as a reduction of 6% on average in the peak consumption by means of the proffered algorithm. Other results of the modeling show conservation potential of 3% if the corridors’ temperatures were to be optimized. Keywords: Intelligent systems, Comfort temperature, Optimization, Artificial Neural Network, Building management Industrial/Professional Applications Setting the corridors setpoint on an optimum temperature can reduce energy consumption in offices up to 3%. In this case, 9% thermal peak reduction is achieved by building management system. Building owners will be able to decrease HVAC system cost up to 20% by using building management systems.

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Adaptive Optimal Control of a VRF System by Using Fuzzy Logic and Utilizing Genetic Algorithm for Optimization of Controller’s Gains

Pouria Naeemi Amini1, Mohammad Bagher Naghibi2

1PhD Candidate, Ferdowsi University of Mashhad, Mechanical Engineering Department

2Assistant professor, Ferdowsi University of Mashhad, Electrical Engineering Department

ABSTRACT

VAC systems should maintain the desirable environmental condition in buildings. In these systems controller must be adaptable to variations of environmental parameters and should have

an optimal behavior in maintaining the desirable condition. Nowadays, most of HVAC systems are on/off type controller or in more advanced cases are PID controllers. Such systems due to the variation of environmental conditions are not optimal and moreover, cannot maintain the desirable environmental condition in acceptable range. Besides, controlling of intelligent air conditioning systems and variable refrigerant flow (VRF) systems becomes more complicated because of increasing controlling parameters. In this paper an optimal adaptive fuzzy controller for a single zone HVAC is presented. This type of controller allows smooth variation of the controller parameters to fit the nonlinearities of the system under control. The proposed controller consists of two layer fuzzy controller. First, controller’s gains are calculated using sugino fuzzy model, and then, input variables are evaluated using a mamdani fuzzy model and control actions are computed. HVAC systems can be controlled by optimal and non-optimal control actions, so identification of optimal and non-optimal situations in these systems are difficult. In this paper, by definition of an objective function, controller’s gains are optimized by genetic algorithm. Performance of proposed controller in tracking of reference variable is shown. It is shown without a notable change in controller’s performance; energy consumption can be decreased by 30 percent. Keywords: adaptive optimal control, VRF systems, sugino fuzzy control, optimal control, optimization of energy consumption.

Industrial/Professional Applications Control of large HVAC systems with fuzzy control is applicable and easier in comparison with other controllers. Increasing number of input and output variables can be done easily. Although, most of the HVAC systems have a good output ranges, they works in non-optimal condition and this increased energy consumption.

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Study of Air Infiltration through Straight Crack

H. Rasouli1, M. Maerefat2, B. Kari3

1M. Sc., Student, Tarbiat Modares University; [email protected] 2Assoc. Prof., Tarbiat Modares University; [email protected] 3Assis. Prof. Building & Housing Research Center

ABSTRACT

ir infiltration has significant effects on energy consumption. Therefore, for determining capacity of HVAC systems the air infiltration through straight crack (a common crack in door lower gaps)

was simulated using FLUENT software. Effect of crack length on air infiltration due to pressure difference in crack sides was investigated. Results showed that, in straight cracks, relationship between rate of air infiltration and crack length is almost linear; thus, rate of air infiltration per unit length ( )Q w is constant and slope of line on the air infiltration rate-crack length chart increase by pressure difference increasing. Keywords: Air infiltration, straight crack, door.

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A Review on Control Systems for Energy Management and Provide Comfort in the Buildings

Faegheh Irannezhad1, Mehdi Moallem2

1Master Student of electrical engineering (Power), AmirKabir University of Technology;

[email protected] 2Proffesor, Isfahan University of Technology; [email protected]

ABSTRACT

ne of the most important challenges in the world that is highly regarded is providing energy and consuming it with high efficiency to supply the future of prosperity human. The aim of the

energy management with providing comfort in buildings is reducing greenhouse gas and allaying many concerns that there is about energy sources and supplying it in the life. In order to achieve this, there are two ways: 1- The making culture of public, 2– Executing engineering plans and development control systems. In this paper, the control systems used to electrical energy management in buildings are utilized, and their advantages and disadvantages are compared with each other. Studies show that using advanced control systems can be caused to supply a high level of comfort and energy savings. These systems are comprised two levels; First level: a feedback control with low levels of indoor conditions for its region, Second level: a surveillance program with a high level (intelligent controller). This high level of management supports the proper functioning strategies for maintaining energy and provides comfortable. Therefore, an advanced control system offers a basic structural unit in an environment complex and energy management system. Keywords: Energy conservation, comfort, Building energy management control systems, Multi-agent intelligent control systems.

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Experimental and Semi-Analytical Study On Natural Ventilation Performance of Different Geometry of One-Sided Wind Catchers

Mohamad Kazemi Esfeh1, Ali Akbar Dehghan2, Mojtaba Dehghan Manshadi3

1MSc of Mechanical Engineering, Yazd University; [email protected]

2Associate Professor of Mechanical Engineering, Yazd University; [email protected] 3Assistant Professor of Aerospace Engineering, Malek Ashtar University of Technology;

[email protected]

ABSTRACT

ne of the most important requirements in designing and constructing the buildings is the proper selection of the air condition systems. Nowadays, due to the technological developments and also

easy access to the fossil fuel resources, air conditioning of the buildings is done by using the active methods. However the brief review of the passive methods used in the lack of mechanical or electrical ventilation systems, clearly shows the art and creativity of our ancestors in utilizing the natural energies to properly air-conditioning their living environments. Wind catchers are very common in natural air conditioning systems. They receive the outer suitable air and induce it into the building. Their function is dependent on the wind flow direction and therefore one of their major defects is that by changing the wind direction, the inlet air flow decreases consequently. In order to overcome this problem, some researchers have suggested wind catchers with circular cross sections, but the problem is that their ventilation capacity is less than the rectangular cross section ones. In this research, detailed investigation has been done on the determination of the structure of flow field within and around the three types of one-sided wind catchers. Furthermore the geometry of a wind catcher which has less sensitivity against the wind direction is introduced in this study. This geometry can also be used in designing more complicated wind catchers. To achieve this particular aim, the ventilation performance of several one-sided wind catcher models is evaluated by experimental investigations. These wind catcher models are: wind catcher with flat roof, wind catcher with steep roof and wind catcher with curved roof. In order to determine the behavior of air flow in and around the wind catcher models, various smoke visualization tests were carried out. The achieved results from smoke visualization tests indicate that the structure of flow within and around the wind catcher is dependent on the geometry of wind catcher roof. To investigate the wind catcher’s ventilation performance at different air incident angle, the induced air flow rate and pressure coefficients around internal surfaces of wind catcher channels are measured. The results show that the wind catcher with steep roof has elevated performance at large wind incident angles in comparison with the other two types selected in the present study. Keywords: Natural ventilation, One-sided wind catcher, Smoke visualization

Industrial/Professional Applications For wind catcher with flat roof, wind catcher with steep roof and wind catcher with curved roof the air flow rate fluctuates by 62%, 37% and 53% respectively as wind angle varies between 0o and 60o. At 60o air incident angle the induced flow rate by wind catcher with steep roof is 66% more than the one for wind catcher with flat roof. The percentage of error between the semi-analytical results and experiments is in the range of 1% and 10%.

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Behavioral Comparison between the Single and the Multi Pressure Traditional Wind Catchers Caused by Variations in Outdoor Wind Directions

M. Aboosaba1, J. Khodakarami2, N. Nasrollahi3, J. Mamizadeh4

1M.A. of Architecture, Ilam University; [email protected] 2Assistant Professor, Ilam University; [email protected]

3Assistant Professor, Ilam University; [email protected] 4Assistant Professor, Ilam University; [email protected]

Abstract

ind flow is the main parameter which generates the indoor flows of wind catcher’s channels. But the impact of alterations in outdoor wind direction still not defined. Therefore in this paper

a comparison between the behavior of single pressure and multi pressure traditional wind catchers have been done, to compare the impact of outdoor wind direction alterations on such structures. CFD modeling used to simulate both types of wind catchers. In this study an outdoor wind speed of 3 m/s in alterations of 0°, 45°, 90°, 135° and 180° was used. Results showed that the type of high pressure area in front of the wind collectors in the wind catcher’s cage impacts on the indoor flow direction in wind catcher’s channel. However in the single pressure wind catchers the flow happens just in one direction, where in the multi pressure wind catchers the flow happens in both upside and downside directions. Simulation showed that in the single pressure type of wind catchers just one high pressure area which was in the front of the wind collector actively was used, where in the multi pressure type all high pressure areas around the cage were used. Key words: wind catchers, vertical flow, CFD.

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Analyzing the Impact of Openings’ Number and Outdoor Flow Direction on the Indoor Vertical Flow Velocity in Traditional Wind Catchers’ Channels

M. Aboosaba1, J. Khodakarami2, N. Nasrollahi3, J. Mamizadeh4

1M.A. of Architecture, Ilam University; [email protected] 2Assistant Professor, Ilam University; [email protected]

3Assistant Professor, Ilam University; [email protected] 4Assistant Professor, Ilam University; [email protected]

Abstract

t has been improved that the behavior of both single and multi pressure types of traditional wind catchers are related to the conditions of lower openings. But still the quantity and the quality of such

relation is not recognized. So this paper aims to indicate the impact of varieties in changing the conditions of such openings and the outdoor wind direction on the velocity of indoor flow in both types of traditional wind catchers. Therefore both types of traditional wind catchers simulated using models in CFD. In this research variations of different border conditions such as lower space without and with opening have been simulated. Also in case of outdoor wind direction, different angles including 0°, 45°, 90°, 135° and 180° tested. Results of this research showed that in different conditions, the multi pressure traditional wind catchers show more stable indoor flow, more predictable behavior and finally more efficiency; compared to the single pressure traditional wind catchers. Key words: wind catchers, natural ventilation, CFD.

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National Codes and Standards in HVAC&R

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A Review on Chapters 17 and 19 of the National Regulations on Buildings, Emphasis on Fresh Air and Air Combustion for Gas Feeding Systems

H. Salarian1, M. Amidpor2, B.Gorbani3, Gh.Salehi4

1Department of Mechanical Engineering, Islamic Azad University Branch of Nour, [email protected]

2Department of Energy system, K.N. Toosi University of Technology, [email protected] 3Department of Energy system, K.N. Toosi University of Technology, [email protected]

4Department of Energy system, K.N. Toosi University of Technology, [email protected]

ABSTRACT

ccording to the article 33 of the state engineering regulatory organization, the Ministry of Housing and Urban Development is the highest authority to supervise and approve the design and

implementation of all construction activities. Compliant with this article the above-mentioned authority has published national standards for constructions in 20 chapters of which chapter 19 concerns with energy conservation, chapter 17 deals with the natural gas piping in buildings and chapter 14 describes heat, air circulation and ventilation. The clauses of chapter 19 have been revised in many occasions and the latest revision has been in 1381 which has been offered to all firms and companies nationwide. The revision of chapter 17 also dates back to 1387. As the national standards of buildings and constructions include, technical, executional and legal aspects which must be unavoidably considered in all construction activities and provides the safety, health, convenience and efficiency of all the citizens, the entirety and flawlessness of these regulations are strongly recommended. Despite modifications which have been applied to the chapter 19, there are still rooms for improvement. In this paper we will review the latest regulations and some important notes to be remembered for fresh air and combustion. Keywords: Fresh Air, Combustion Air, National Regulations on Buildings.

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Industrial HVAC&R

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Ventilation Network Design for Stope 3 Mine 1 Parvadeh Tabas

Mohammad Amin Zareie darmian1, Mohammad Javanshir Giv2, Farhang Sereshki3

1 MSc Student Mining Engineering Department, University of Birjand . Birjand . Iran.

2 Assistant Professor, Mining Engineering Department, University of Birjand. Birjand.Iran . 3 Associated Professor, Mining Engineering Department, Shahrood University, of Technology. Shahrood . Iran.

ABSTRACT

n mine designing issue, the proper ventilation system is a vital factor. There are a various type of gases and dust in mines atmosphere. These contaminations must be removed from working area. So that

fresh air supply for underground miners. In Parvadeh coal field , coal seams are very gaseous According to clean- air act, In this mine maximum grade of methane gas is 1.25 percent. In Parvadeh coal mine the main ventilation is through suction. In mine No 1 , tunnel 1,2,3 are intake pass for fresh air and contaminated air return from ventilation shaft . In this paper ventilation calculations performed and result compared with Ventsim software. The results show that two methods were consistent with together. Keywords: Methane gas - Mine ventilation - Parvadeh – advance Tunnel – Exhaust fan.

Industrial/Professional Applications The Air requirements for advancing Stope 3. The Air requirements for extraction Stope 3. The Air requirements for total Stope 3 and selection Exhaust fan. Offer the use of methane gas in the air to fuel power plants and mines in the area of electrical energy. Prevention of environmental problems of methane gas.

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Experimental Analysis of Aircraft Individual Air Distribution System Design

Mohammad Hadi Esteki1, Sayed Mohammad Reza Afghari2, Sattar Shahbaz3

1Air Condition System Expert, Aeronautical Design Center of Iran Aircraft Manufacturing Industries Co.; [email protected]

2Air Distribution System Expert, Aeronautical Design Center of Iran Aircraft Manufacturing Industries Co.; [email protected]

3 Life Support Systems Dep. Manager, Aeronautical Design Center of Iran Aircraft Manufacturing Industries Co.; [email protected]

ABSTRACT

n environmental control system (ECS) is used to protect passengers and crew members in an aircraft from different pressure, moisture and temperature of ambient environment. The air distribution system is an

important component of the environmental control system since it is used to distribute conditioned air properly to the cabin, providing a healthy and comfortable cabin environment. So it is very challenging to design or develop a comfortable and healthy cabin environment for aircrafts with special mission. In order to add air gasper system as an individual air distribution system to an air distribution system of an aircraft with special mission, simple calculations and experimental validation will be help to achieve design criteria in the best way. The passenger air gasper system is installed in addition to cabin main air supply. The gasper supplies the same conditioned air from the air conditioning pack. The air gaspers are supplied by existing cabin main duct having series of outlet holes/perforations for cabin cooling. The ducting system pressure loss analysis contains a performance calculation based on geometric construction of the upper duct and gasper configuration. The ducting system is assumed has two types of outlets, gasper outlets and upper duct slot outlets. Results show that the minimum velocity of the air at duct perforation holes of 1.87 m/s decreases to 0.98 m/s in the outlet (slot) and the maximum velocity of the air at perforation holes of 12.68 m/s decreases to 3.8 m/s. With all in open position the air flow extracted by gaspers from the duct is 2.29% (4.67 cfm from total ECS supply of 202.95 cfm). Throw distance for duct is calculated about 17 inches. In according to the ECS supply, the air outlet velocity of perforations was measured by velocity gage equipment. The average of each section has been compared with theoretical results. The most different is about 28% that has happened at third section of perforation holes because of flow turbulence intensity and reality condition of air flow throw the duct. Finally design results show good agreement between air flow throw gaspers and gasper to passenger distance that makes comfortable air feeling conditions. Also the experimental analysis on the mockup validates results of outlet velocity of gaspers and perforations calculations. Therefore adding of gasper system to available distribution system was designed in according to least modifications, suitable location and good air flow throw gaspers. It was found the upper duct air distribution among gaspers is relatively uniform. In addition, the agreement between the air velocity calculations results and the experimental data is reasonably good.

Keywords: Air distribution system, Aircraft, Gasper, Environmental control system, Pressure Loss. Industrial/Professional Applications

Results of the article can be applied for aircraft air distribution systems design. Simple calculations and experimental validation will be help to achieve design criteria in the best way. Validating by air distribution mockup in operational condition decrease design risk instead of simulating by some assumptions.

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Design of Ventilation System for the Niayesh Roadway Tunnel

S.Shahbazi1, M.Amjadi2, G.Heidarinejad3

1M.S student, Tarbiat Modares University; [email protected] 2M.S student, Tarbiat Modares University; [email protected]

3Proffesor, Tarbiat Modares University; [email protected]

ABSTRACT

n this paper, the design of normal and emergency ventilation system for Niayesh tunnel has been offered. The whole length of the tunnel is totally 6190 meters. Niayesh tunnel includes two separate

one-way tunnels. Kurdestan tunnel is a part of north tunnel and its length is 1053 meters. There are two different methods for designing the ventilation system for tunnel. In the first method, computational fluid dynamics and in second method semi-empirical data is used. In this paper the design is done based on semi-empirical methods using PIRAC standards. CO and NOx are the two Pollutants which are studied in this paper. The amount of air flows required for ventilation of north, south, and Kurdestan tunnel are calculated 841, 621, and 202 cubic meters per second respectively. Considering the length of tunnel, use of forced ventilation system is essential. Due to special conditions of the structure the longitudinal ventilation system is used. Longitudinal ventilation can be done using five different methods and the appropriate method is selected considering the range of air speed in the tunnel. While the maximum air flow speed has not been exceeded the limited speed, (10 meters per second) longitudinal ventilation with jet fans can be used. The number of required jet fans, considering the allowable concentration for CO, in north, south, and Kurdestan tunnel is calculated 101, 46, and 4 respectively. It is important that ventilation system must be accountable in critical situations such as fire. Our main goal in dealing with fire is to conduct heat and combustion products to one side and preventing return flow. The critical velocity is the minimum air flow velocity that prevents any return flow. In this situation the combustion products be conducted to one side and individuals can be approached from the other side of the fire and take off the fire. Regarding the calculations, the amount of air flow required for the emergency state was less than normal state (Due to the excessive length of the tunnel, this was predictable). So the ventilation for normal state will respond to emergencies. During the fire it is recommended to turn off the jet fans located near the fire center. Keywords: tunnel ventilation, semi-empirical method, Niayesh tunnel


Results of the article can be applied for design of ventilation system for Niayesh roadway tunnel. Advantages of semi-empirical methods were studied to use in design of any tunnel ventilation system. Results can be applied for choice of ventilation equipment in roadway tunnel.

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Criteria of Effectiveness Evaluation of Centrifugal Pumps in District Heating Systems

Egils Dzelzitis1, Deniss Pilscikovs2

1Riga Technical University/Institute of Heat, Gas and Water Technology; [email protected] 2Riga Technical University/Institute of Heat, Gas and Water Technology; [email protected]

ABSTRACT

he goal of this research is the derivation of criteria of effectiveness evaluation of variable speed centrifugal pumps in district heating systems.

For this purpose, the efficiency level of centrifugal pumps of various designs has been analyzed at certain head and flow range. There is also the change of the efficiency level of circulators has been investigated in the article. It has been done at different deviations from the nominal pump head. As a criterion, the effectiveness of the proportional pressure control mode has also been analyzed for centrifugal pumps with variable speed motors. It has been done if the proportional pressure control mode is used in comparison with the constant pressure control mode. For these reasons, a great number of energy analyses have been realized for different pumps and the regression equations with the coefficients of determination have been derived. As the result, the three criteria of effectiveness evaluation of centrifugal pumps have been derived. These criteria are design of centrifugal pumps; duty point location comparatively the nominal pump head; use of the proportional pressure. The trend of the reduction of energy consumption has been determined. In this connection the regression equations have been derived. The conclusions are as follow: • Vertical in-line single-stage pumps are less efficient in comparison with horizontal end-suction single-stage pumps, when the flow rate varies from 20 to 220 m3/h at the definite range of the head (from 10 to 72 m). The difference in the efficiency level of the centrifugal pumps is from 3% up to 6% at the definite range of flow and head. • The reduction of annual energy consumption can be achieved up to 33%, if the proportional pressure is applied and the deviations from the head value of duty point at zero flow declines up to 60%. • The efficiency level drops up to 3% if the deviation of the head value of the best efficiency point is up to 30% from its nominal value. • A slight decrease of the efficiency level is observed if the deviation from the nominal head value is up to 30%. If the head deviation is above 30%, then the efficiency level drops rapidly. Keywords: centrifugal pump, control mode, efficiency

Industrial/Professional Applications Results of the article can be applied for pump audit in low and medium-scale HVAC systems. Results allow increasing the level of efficiency in HVAC systems, thus contributing to energy saving in the world. Results of the article can be used as a guide for designers with a focus on pumping systems.

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New Emerging Technologies in HVAC&R

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Energy and Exergy Analysis of Different Cogeneration Heat and Power Systems in Buildings

Mohsen Fallah

Assistant Lecturer, Azarbijan University of Tarbiat Moallem; [email protected]

ABSTRACT

n this Paper, performance of different heat and power cogeneration systems used in buildings (residential, commercial and administrative applications) is evaluated based on energy and exergy

efficiency. In this paper four cogeneration systems including; prime mover steam turbine, gas turbine, diesel engine and geothermal are investigated/studied. After power generation, remained energy is recovered by a heat exchanger for space heating. Output product (heat and power) for all systems, except for diesel system are considered the same due to have a simpler comparison. Results Show that Diesel engine and geothermal systems have higher efficiency than steam turbine and gas turbine systems. Using of cogeneration systems with high energy consumption is more useful and has a peripheral role in the fuel consumption and reduction of environmental pollution. Keywords: Cogeneration, Turbine, Geothermal, Exergy Industrial/Professional Applications • Diesel engine and geothermal systems for heating buildings have higher exergy efficiency (47.8 and 44.2, respectively) compared with the steam turbine and gas turbine (23.2 and 22.5, respectively. • The exergy efficiency for systems with fossil fuels such as steam turbine and gas turbine is slightly less than half of energy efficiency. • Cogeneration heat and power through the geothermal systems is 2.1 times more profitable of production of heat and power distinctly.

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Numerical Study of the Effects of Water-Al2O3 Nanofluid on Underfloor Heating System

Shaban Alyari1, Kamran Mobini2, Mahmood Ranai3

Assistant professor and faculty of Mechanical, Shahid Rajaee teacher training university; [email protected] 1 Assistant professor and faculty of Mechanical, Shahid Rajaee teacher training universit; [email protected] 2

[email protected] MSc student of mechanics, Shahid Rajaee teacher training university; 3

ABSTRACT

n this work, the effects of water-Al2O3 nanofluid on the performance of an underfloor heating system are numerically investigated. At first, Flow field and heat transfer were simulated in an

underfloor heating system using water as the working fluid. The Fluent mixture model was used for a three dimensional flow at both steady and transient conditions. To validate the numerical results, they were compared with some experimental results. This showed the acceptable accuracy of the numerical results. Then the same method was applied to simulate the flow of water-Al2O3 nanofluid as the working fluid. The inlet temperature was taken to be 36 degrees and the nano-particle volume fractions of 1 to 5 percent were used. The results showed that the floor temperature was increased for one degree when nanofluid with concentration of %5 relative to pure water. In addition, effect of concrete, ceramic and wooden flooring have been studied on the system performance and floor temperature. Ceramic floor showed an increase of 2.31 degrees in floor temperature relative to wood flooring. A uniform floor temperature was found when nanofluid was used as the working fluid on the floor with ceramic cover. This is a good sign for the human comfort in underfloor heating system. Keywords: nanofluid, two phase flow, mixture model, underfloor heating Industrial/Professional Applications Using water-AL O nanofluid in underfloor heating system decreases energy consumption by 10 percent. Using concrete floor with high thermal conductivity decreases the starting time of the heating system.

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Thermodynamic Analysis of Combined Power and Refrigeration Cycle with HCCI Engine Prime Mover

N. Sarabchi1, R. Khoshbakhti Saray2, S.M. Seyyed Mahmoudi3

1M.Sc. of Mech. Eng., Tabriz University; [email protected]

2 Associate Prof. of Mech. Eng., Sahand University of Technology; [email protected] 3 Associate Prof. of Mech. Eng., Tabriz University; [email protected]

ABSTRACT

n recent years, Homogeneous Charge Compression Ignition (HCCI) has been introduced as a new and practical technique in both moving and stationary internal combustion engines. HCCI engines offer a new alternative for cogeneration that provides a combination of low cost, high efficiency and low emissions. On the other hand flexibility in using alternative fuels is the main advantage of this kind of combustion system.

In Homogeneous Charge Compression Ignition (HCCI) combustion, a lean premixed charge combusts simultaneously in multiple sites. In this type of engines, combustion is faster than typical SI and CI engines. In this paper, a homogeneous charge compression ignition engine and an ammonia-water absorption cogeneration cycle were combined. The combination was in such a way that the energy of exhaust gases was utilized to power the absorption cogeneration cycle and the waste heat of the cooling water of the HCCI engine was recovered to produce heat. The developed thermodynamic model for HCCI engine was a single zone model with capability to consider chemical kinetics calculations which is homemade software in Fortan environment. The time dependent values of temperature, pressure and the concentrations of the chemical species involved in the reactions can thus be calculated. The predicted results for engine combustion and performance characteristics are in good agreement with the corresponding experimental data. The bottom cycle was modeled in EES software. Then by linking these two programs, a parametric analysis was conducted to evaluate the effects of each major thermodynamic parameter on the performance of the combined power- refrigeration cycle such as pressure ratio of the pump, basic solution ammonia concentration, refrigeration temperature and turbine inlet temperature. The results obtained from parametric analysis show that, increasing the pressure ratio causes a decrease in refrigeration output and an increase in first law efficiency. Also second law efficiency reaches to an optimum value then decreases as the pressure ratio increases. By calculating the exergy destruction ratio, the exergy destruction in the engine has the maximum amount among those occur in other components and absorption cogeneration cycle has less effect in exergy destruction. In the condition of basic solution ammonia concentration of 0.4 and ambient temperature of 25oC, maximum exergy efficiency occurs when pressure ratio is 8.727. In the mentioned condition, the second law efficiency of the combined cycle is 6.63% higher than the second law efficiency of the HCCI engine and the fuel energy saving ratio is 28.83%. Keywords: HCCI, Absorption refrigeration, Exergy

Industrial/Professional Applications HCCI engines are a new alternative for cogeneration systems because of having advantages such as: low cost, high efficiency, low emissions and flexibility in using alternative fuels. Small-scale tri-generation systems with HCCI engine prime mover can be used in residential and commercial regions in order to produce power, heat and cold simultaneously. The combined cycle proposed in this paper has the fuel energy saving ratio of 28.83%. The second law efficiency of the combined cycle is 6.63% higher than the second law efficiency of the HCCI engine.

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Modeling of Micro Combined Heat and Power Systems (MCHP) for Residential Applications Using the Gas Internal Combustion Engine

Seyed Hashem Samadi1, Barat Ghobadian2, Gholamhassan Najafi 3, Saied Faal4

1Master of Science Student, Tarbiat Modares University; [email protected]

2Associate Professor; Tarbiat Modares University; Corresponding author: [email protected] 3Assistant Professor; Tarbiat Modares University; [email protected]

4Master of Science Student, Tarbiat Modares University; [email protected]

ABSTRACT

sing of new method and technology of energy production that does not have the disadvantages of classical methods has been common in the world. One of these new technologies is combined

heat and power. Recent progress in technology has made possible the development of micro combined heat and power (MCHP) for dwellings and small buildings. These systems, which produce electricity, heat and hot water, might soon replace the traditional boilers. Internal combustion engines are already available, and more efficient technology will be available in the near future. In this paper, combined heat and power systems using the gas internal combustion engine has been modeled. Also, technical potential of its production in micro scale for residential applications has been investigated. The results indicated that 29920 kJ/h was the amount of heat energy that was generated by combustion in a single cylinder internal combustion engine with a power 4.9 kW that works with natural gas fuel was. Also, results show average heat energy from engine exhaust is about 4019/89 kJ/h. According to calculations, product of total heat transfer coefficient and heat transfer area for heat exchanger 226.72 W/K was obtained. Considering 14 percent of waste energy from the exhaust gases, daily consumption of heat energy a 4 or 5 person households can be supplied by selecting a suitable heat exchanger, which is about 34635.684-38089.746 kJ. Also according to the electrical needs in a 4 or 5-person households, this engine - generator will be able to resolve electric charge for residential application. Keywords: Combined Heat and Power, Combustion Engine, Energy, Modeling. Industrial/Professional Applications Considering 14 percent of waste energy from the exhaust gases, using the gas engine - generator exhaust heat is suitable option for heat production requirements in the residential application. Combined heat and power systems introduced in this article will be able to provide electricity and heat to 4 or 5 person households. The introduce technology in study is a more efficient compared to generators that only produce electricity due to makes maximum use of exhaust gases that would be lost.

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An Empirical Study on the Effects of Horizontal Corrugated Tubes on Heat Transfer and Pressure Drop of Nanofluid Flows

M.Karami1, M.A. Akhavan-Behabadi1, M. Jamali2

1School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran

2Building and Housing Research Center, Tehran, Iran

ABSTRACT

he forced convective heat transfer and pressure drop in horizontal corrugated tube have been experimentally investigated. The main aim was to examine combined passive techniques based on

wall corrugation and adding nano-particles. Heat transfer oid and carbon nano-tubes1 were used to make nano-fluids. 3 mass concentrations of 0.05, 0.1 and 0.2 percent were applied. Physical characteristics of these nano-fluids have been measured and reported in present note. Flow is considered fully developed hydrodynamically, but it is located in thermal entry length. Range of Reynolds number is from 100 to 4000, thus this investigation includes laminar and turbulent regimes. 3 tubes corrugated from 4sides, with hydraulic diameters of 11.89, 13.2, and 15.51 millimeters were used. The depths of corrugations are 0.9, 1.1 and 1.3 millimeters which make 2 depth ratios of 0.07 and 0.1. The pitch of corrugation is 14 millimeters which make 3 pitch ratios of 0.9, 1.06 and 1.18. Length of the tubes is 1200 millimeters. Boundary condition of constant temperature has been investigated. Nano-fluid was flowing inside the tubes while the tubes were located inside a vapor bath with temperature of 95 °C. In this note, results obtained by experiments on corrugated tube are presented and are compared with those of straight tubes. Results may be categorized in 3 main types: first one is concerning heat transfer, second one concerning pressure drop and third one concerning transferred heat vs. required energy for this transference. Results showed adding nano-particles augments Nusselt number from 4 to 40 percent, while it increases pressure drop from 6 to 40 percent. Corrugating the tubes also enhances Nusselt number from 99 to 137 percent; on the other hand it makes f (Darcy’s friction factor) to rise 3 times. Keywords: nano-fluid, heat transfer, pressure drop, constant temperature boundary condition, corrugated tubes.

Industrial/Professional Applications In this paper it is shown that corrugating the tubes, enhances the heat transfer coefficients Also adding nano-particles to base fluid augments Nusselt numbers from 4 to 40 percent.

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Experimental Investigation on Heat Transfer of Nanofluid Laminar Flow in U-Bend Tubes with Different Bend Radiuses

M.Saadati1, M.A. Akhavan-Behabadi1, M. Jamali2



ABSTRACT

n this paper, an experimental study has been carried out to investigate the effect of adding Multi Wall Carbon Nano Tubes (MWCNT) to the Heat Transfer Oil on heat transfer and pressure drop

characteristics of U-bend tube with different bend radiuses. The experiments have been done for pure heat transfer oil and nanofluid with different mass concentration inside U-bend tubes under uniform wall temperature condition. Test sections were in a steam chamber to be compatible with the uniform wall temperature condition. Heat transfer oil (HT-B) and MWCNT- Heat transfer nanofluids with weight fraction of 0.1%, 0.2% and 0.4% have been considered as the working fluids. The rheological characteristics of nanofluids including density, thermal conductivity, viscosity and specific heat have been measured experimentally. Based on these measurements, some correlations have been proposed to predict the rheological properties of nanofluids with different weight fractions. The results of the experimental measurements showed that adding nano-particles to the base fluid would lead to an increase in density, thermal conductivity and viscosity of the nanofluid and may decrease specific heat of the base fluid. The results obtained for convective heat transfer of flow inside U-bend tubes indicated that by decreasing U-bend diameter, the convective heat transfer coefficient increases. Also, it was observed that utilizing nanofluids instead of base oil may enhance the convective heat transfer coefficient remarkably. Keywords: Heat transfer, nano fluid, uniform wall temperature, U-bend tube.

Industrial/Professional Applications In this paper it is shown that by decreasing the U-bend radius, the convective heat transfer coefficient increases. Also, it was observed that utilizing nanofluids instead of base oil may enhance the convective heat transfer coefficient remarkably.

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Experimental Study of Charging Process in Thermal Energy Storage System Using Phase Change Material

Hamid Jahedi Amlashi1, Hossein Shokouhmand2, Babak Kamkari3

1M.Sc Mechanical Engineering, Department of Mechanical and Aerospace Engineering, Science and Research

Branch, Islamic Azad University, Tehran, Iran; [email protected] 2Professor, School of Mechanical Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran;

[email protected] 3Ph.D Student, School of Mechanical Engineering, Faculty of Engineering, University of Tehran, Tehran, Iran;

[email protected]

ABSTRACT

hermal energy storage (TES) systems have played an important role in energy management, and have been used extensively in refrigeration and air conditioning systems. In addition, these

systems can reduce the mismatch between energy supply and energy demand. The use of a latent heat storage system using phase change materials (PCMs) is an attractive way of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. In this work, the effect of increasing temperature of charging process was studied experimentally in a thermal energy storage system containing a phase change material. Result indicated that the maximum amount of stored energy was 240 kJ/kg in the charging process. Furthermore, the charging processing time was reduced 42%, the storage energy was increased 7% and heat transfer rate was increased 84% when the temperature of heat exchanger was increased 10°C. Keywords: Energy Storage, PCM, Thermal energy storage systems.

Industrial/Professional Applications Energy Management Control the difference between demand and supply of thermal energy. Reduce the amount of load on the network usage at the peak hours. Energy Conservation & Optimization.

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Augmentation of Heat Transfer of MWCNT/Heat Transfer Oil Nanofluid Laminar Flow inside Helically Coiled Tubes

M. Fakour-Pakdaman1, M.A. Akhavan-Behabadi1, M. Jamali2



ABSTRACT

n this study, heat transfer enhancement of nanofluid flow inside inclined helically coiled tubes has been investigated experimentally in the thermal entrance region. The temperature of the tube wall

was maintained uniformly to be compatible with isothermal boundary condition, at nearly 100oC Experiments were conducted for fluid flow inside straight tubes and helical ones. A wide range of different parameters has been considered. Reynolds (Re) varied between 10 and 1900 and Dean (De) from 5 to 400. In addition, pitch to tube-diameter ratio (P/d) ranged between 1.6 and 6.1 and coil-to-tube diameter ratio (Dc/d) varied from 14.1 to 20.5. In order to investigate the effect of the fluid type on the heat transfer, pure heat transfer oil and nanofluids with weight concentrations of 0.1, 0.2 and 0.4% were utilized as the working fluid. Based on the experimental data, heat transfer goes up with nanoparticle concentration and pitch ratio. However, larger coil-to-tube diameters lead to lower heat transfer rates. It is also shown that applying helical coils instead of straight tubes results in a remarkable heat transfer enhancement. Keywords: Nanofluid; Heat transfer; helical coiled tubes; MWCNT

Industrial/Professional Applications It is shown that geometric parameters have been very effective on heat transfer results. Regardless of the type of fluid, at high Reynolds numbers, reducing the coil diameter and increasing the coil pitch, increase the heat transfer rate, dramatically. The use of both helical tubes and Nanofluides may increase the rate of heat transfer as much as 10 times.

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Applications of Phase Change Materials in Air Conditioning and Methods of Heat Transfer Enhancement: A Review

Hamid Jahedi Amlashi1, Morteza Khayat2

1M.Sc Mechanical Engineering, Department of Mechanical and Aerospace Engineering, Science and Research

Branch, Islamic Azad University, Tehran, Iran; [email protected] 2Department of Mechanical and Aerospace Engineering, Science and Research Branch, Islamic Azad University,

Tehran, Iran

ABSTRACT

nergy storage plays an important role in improving application, performance and reliability of wide range of energy systems. There is a general consensus that the energy storage system enables

us to lower the difference between the demand and supply of energy. Thermal energy storage systems can store an excessive amount of energy from hot or cold sources while demands are low, and use it at the peak hours of energy usage. The advantages of these novel systems, in addition to energy conservation and optimization, is reduce the amount of load on the network usage at the peak hours and enabling smaller systems to be used with less initial investment. The use of a latent heat storage system using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. Keywords: PCM, Thermal energy storage systems, Heat transfer.

Industrial/Professional Applications Control the difference between demand and supply of thermal energy. Store an excessive amount of energy that generated by facilities systems when demands are low, and use it at the peak hours of energy usage. Reduce the amount of load on the network usage at the peak hours. Energy Conservation & Optimization. Reduction environmental pollution.

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Design Combined Cooling, Heating and Power System for Residential Building in Hot Climates in Iran

Hasan Ghasemzadeh1, Mehdi Maerefat2, Aziz Azimi3

1M.S student, tarbiat Modares University; [email protected]

2Department of mechanical engineering, Tarbiat Modares University; [email protected] 3Department of mechanical engineering, Shahid Chamran university of Ahvaz; [email protected]

ABSTRACT

ombined cooling, heating and power (CCHP) systems use waste heat from on-site electricity generation to meet the thermal demand and the cooling demand by absorption chiller. This paper

presents a mathematical analysis of CCHP system in comparison to separate system. The cchp system following 1- maximum electrical demand management (MEDM), 2- maximum thermal demand management (MTDM), 3- maximum rectangle electrical demand management (MREDM), 4- maximum rectangle thermal demand management (MRTDM). two relative criteria, primary energy saving (PES), carbon dioxide emission reduction (CDER) are employed to evaluate the performances of cchp systems, for a hypothetical residential building with five floor in hot climate zones in Bandarabbs. Finally payback period is calculated. Two methods were investigated for supply cooling demand: 1-only absorption chiller, 2-absorption chiller with auxiliary electric chiller. The results indicate that CCHP system in all strategies in hot climate achieves more benefit over separate system and in all these strategies, cooling demand supply by absorption chiller with auxiliary electric chiller. MEDM is the best strategy. In this strategy PES and CDER are 20% and 14%, respectively. Keywords: Combined cooling, heating and power, Primary energy saving, Carbon dioxide emission reduction, Absorption chiller

Industrial/Professional Applications If cooling demand supply by absorption chiller with auxiliary electric chiller, MEDM is the best strategy, in this strategy PES and CDER are 20% and 14%, respectively. If cooling demand supply only by absorption chiller, cchp system is not appropriate for residential building in Bandarabbas. Payback period is five years.

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Experimental Approach to Enhance Solar Water Heater using Phase Change Materials

Mohammad Ali Fazilati1, Ali Akbar Alemrajabi2

1PHD student, Mechanical department, Isfahan University of Technology; [email protected] 2Assistant professor, Mechanical department, Isfahan University of Technology; [email protected]

ABSTRACT

n this research, the effects of using Phase Change Materials (PCM) as storage medium on the performance of a solar water heater have been experimentally investigated. A type of paraffin with

special thermodynamic properties is used as PCM in spherical capsules in conjunction with water as storage material in the tank of solar water heater. The solar radiation modeled as weak, mean and strong by circulating water with three temperature levels of 40, 60 and 80oC in jacket of tank. The energy and exergy efficiencies of solar water heater and the time the heater can supply hot water have been compared before and after use of PCM in tank. It is observed that using PCM in the tank the energy storage density is increased in the tank up to 39% and the exergy efficiency is enhanced up to 16%. Also, it is observed that solar water heater with PCM, can supply hot water with specified temperature at 25% larger time compared to pure water tank. Improvement in thermal stratification has been observed by examining temperature histories of different water layers in the tank. Keywords: solar water heater, PCM, Enhancement, energy and exergy efficiency

Industrial/Professional Applications Industrial application that can be inferred as a result of this work is technical justification of using PCM, especially paraffin wax, as a storage material in solar water heaters. Keeping in mind the relative low cost of paraffin as a PCM against other such materials, this work focus on enhancing a solar water heater from exergy and energy aspects as a result of employing paraffin in our model as proceeded: The time period of supplying water heater is increased up to 25% The heat storage energy density of tank is increased up to 39% and thus decreases the overall weight of system. Exergy recovery of heater improves and consequently the outlet water from heater equipped with PCM has a relatively higher temperature, at the same conditions.

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Environmentally Friendly Air-Conditioning,

Cooling and Refrigeration Techniques

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The Trials and Tribulations of Creating an HFC/HCFC Free Food Processing Plant by Installing a Two Stage Transcritical CO2 Refrigeration Plant

K. Visser

KAV Consulting Pty Ltd, P O Box 1146, Kangaroo Flat, Vic, 3555, Australia

Tel: (03) 5447 9436 Fax: (03) 5447 9805, [email protected]

ABSTRACT

he two stage transcritical CO2 refrigeration plant replaces twenty two independent systems comprising air cooled HFC and HCFC cooling systems for blast freezing, cold and chill storage,

office AC, factory cooling, process water chilling and water heating by gas and R134a heat pumps, and electric defrost, freezer door fascias and under floor heating. Nine compressors are used comprising three high stage compressors and two AC compressors with one common standby plus three boosters including one standby. Operating conditions are +5°C SST for office AC, –5°C SST for high stage and chilling duties and –40°C SST for the cold store and blast freezer. The AC compressors also serve as parallel economizer compressors to reduce the flash gas flow to the rest of the system for chilling and freezing accounting for 75% of the system’s high stage capacity. This produces a high COP for the high stage compressors. The AC and high stage compressors may discharge either to the two stage gas cooler or two water heaters in series to heat water to 80°C. In subcritical mode, the significantly oversized adiabatically assisted gas cooler will allow condensing at 5 K temperature difference between air entry dry bulb and condensing temperatures. Keywords: Transcritical, CO2 refrigeration, water heating, parallel compression, economizer.

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The Energy Efficiency in Office Buildings and Hospitals Using Total Energy NH3 and CO2 Systems Separately and Combined for Heating and Cooling

K. Visser

KAV Consulting Pty Ltd, P O Box 1146, Kangaroo Flat, Vic, 3555, Australia

Tel: (03) 5447 9436 Fax: (03) 5447 9805, [email protected]

ABSTRACT

t is becoming increasingly clear that HFC refrigerants are offering a solution to the problem of Ozone Depletion Potential (ODP) associated with CFC’s and HCFC’s, but have done very little, if

anything at all, about the Global Warming Potential (GWP) associated with the use of CFC and HCFC chemical refrigerants. The GWP of the new HFC family of refrigerants is now becoming an increasing concern. The other major issue is the specific energy consumption per square metre of occupied building area for both heating and cooling as shown in a USA Department of Energy report dealing with Thermal Distribution, Auxiliary Equipment and Ventilation and the Energy Consumption Characteristics of Commercial Building HVAC systems in the USA comprising 3,345 million m2 of cooled building floor space plus 4,459 million m2 of heated building floor space. A solution to both these problems is possible by using the natural refrigerants Ammonia (NH3) and Carbon Dioxide (CO2), both of which were used extensively in building cooling before the advent of chemical refrigerants in the early 1930’s. It is shown, that NH3 has already made a significant return in the cooling of buildings because of its thermodynamic efficiency and because its GWP = 0. The high potential of NH3 systems to be used for both cooling and heating of large buildings is demonstrated in terms of energy efficiency and 0 GWP. When retrofitting NH3chillers and heat pumps into buildings for heating and cooling, the primary energy consumption, electrical energy consumption and attendant emissions per m2 of office building would reduce by 14%, 35% and 30% respectively. In the case of retrofitting CO2chillers with heat recovery, the reductions per m2 would be 18%, 52% and 33% for electrical energy consumption, primary energy consumption and emissions respectively. Purpose designed and built CO2 heating and cooling plants for office buildings would yield estimated reductions per m2 of48% in electrical energy, 59% in primary energy and 57% in emissions, whilst in the case of similar NH3 plants these reductions are estimated at39%, 54% and 50% respectively. In the case of hospitals the percentage reductions in electrical energy, primary energy and emissions per m2are generally greater when comparing these reductions to those estimated for office buildings for both retrofitting and purpose designed natural refrigerant systems. This is most likely caused by the fact that hospitals operate 24 hours/day, 365 day/year.

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Optimization in Nitrogen Liquefier with Mixed Refrigerant

Ehsan Soltani1, Mostafa Mafi 2, Majid Amidpour 3

1Department of Energy Research Engineering, Olom Tahghighat, Azad University, Tehran, Iran

2Departments of Mechanical Engineering, I.K. International University, Qazvin, Iran 3Departments of Mechanical Engineering, K.N.Toosi University of Technology, Tehran, Iran

ABSTRACT

owadays there are a lot of processes which need the low temperature (sub ambient). Minimizing the work consumed of these systems is the most effective measure to reduce the cost of products

in sub ambient chemical processes such as nitrogen liquefaction plants. One of these ways is using the mixed refrigerant cycle (MRCs).Numerous mixed refrigerant cycles were developed in the past several decades in different applications. In this paper, first of all, one nitrogen liquefaction system with pure working fluids has been studied, and then two sets of low temperature MRCs are developed and simulated for a typical nitrogen liquefaction plant utilizing a mixture of methane, ethane, propane and nitrogen as cycle working fluid to replace the pure nitrogen refrigeration cycle .The key parameters of the cycles including mixture compositions and operating pressure levels are optimized to meet the objective of minimum shaft work in compressor. The results show that a different mixture composition has different optimal working consumption. Also the simulation results show that MRCs can improve the thermodynamic performance of refrigeration system using the optimal working fluid mixture composition, optimal high and low operating pressures, and then the effect of changing the key parameter has been studied in this study. Keywords: Liquid Nitrogen, Mixed refrigerant, Cryogenic, Optimization

Industrial/Professional Applications Using the mixed refrigerant instead of pure refrigerant to finding the best efficiency. New simulation method minimizing the power consumption with finding the best mixture composition. At last the result is compared together, and the study shows that using the mix refrigerant is more efficient with comparing to pure refrigerant.

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Investigation of Leaked Air Into Cycle and Its Purging Effects on Air Cooling Chiller Cycle of Cryogenic Nitrogen Generation Unit

Esmaeil Bahmyari1, Hamidreza Miri2, Mostafa Jahankhah3

1Ms in Mechanical Engineering, SPGC; [email protected] 2Bs in Electrical Engineering, SPGC; [email protected]

3Bs in Mechanical Engineering, SPGC; [email protected]

ABSTRACT

n air cooling refrigerant cycles when air pressure is higher than refrigerant pressure, air can leak through evaporator tubing to the cycle. In this paper first, effects of leaked air into refrigeration

cycle is investigated and then amount of air in system is estimated. After that, effects of manual purging of air on the cycle performance are investigated. Results and observations show the air in the cycle severely decreases heat transfer efficiency of the cycle and life of mechanical elements. Also manual purging of air from the cycle causes refrigerant losses that contribute both directly and indirectly to global warming through inefficient system operation, increased power consumption and greenhouse gas emissions and higher maintenance costs. Keywords: Air purging; manual purging; air leakage; refrigerant

Industrial/Professional Applications Using water with 2 bars as medium fluid for exchanging heat between refrigerant and air can prevent leaking air. Air in the cycle increase power consumption and consequently lower cycle performance. Manual purging of air causes refrigerant losses that contribute to global warming and cycle performance. Using automatic purger can prevent refrigerant loss and lower maintenance costs in these cases

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Indoor Air Quality and Comfort Conditions

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Elevation Analysis of Potential Requirements for Heating and Cooling From Viewpoint of Climate According To Humidity & Temperature

Zahra Kazemnezhad1, Bahman Ramezani2

1M.A in climatology in environmental planning, Islamic Azad University, Rasht branch;

[email protected] 2Associate professor in Physical Geography, Islamic Azad University, Rasht branch; ir.ac.iaurasht@Bahman

ABSTRACT

oday has proved the necessity of attention to climatic conditions in design and construct of buildings and it is very important in two reasons: for one thing climatic design for building can

prepare a thermal comfort conditions for man and in the other hand it will reduce the energy consumption costs. Recognition of climatic conditions and study of requirements of heating and cooling in the every region is a very important section for programming for access to comfort conditions and weather quality in the closed spaces. The deviations of mean daily temperature from man comfort temperature (truncation temperature) are called degree-day. On this research with use of average temperature and humidity statistics stations in Anzali, Rasht and Masouleh (3 topographical units of the coast, plain and mountain) and degree-days model (for requirements to heating and cooling) has paid to estimate amount requirements for the thermal environment in warm and cold months of the year. The result of paper has shown that from coastal zone to mountainous area has changed from 1397 to 2345 degree - days and requirements for cooling in this cross elevation is 1019 to 453 degree – days. Keywords: temperature, humidity, comfort, climatic design.


The results of statistical studies show that solidarity coefficient between elevation of sea level and amount of requirements for heating and cooling is significant 99%. Anzali and Rasht stations H3C2R4 have a climate to cold relatively winters with thermal requirements 1000 - 1500 degree-day and temperate summer with cooling requirements 100 - 500 degree - day, while Masouleh station H5C1R4 have a cold climate with thermal requirements 2000 - 3000 degree - day and mild summer with cooling requirements 0 – 100 degree - day. The comparison of HDD and CDD in this stations show that must has paid to necessary operations for combating to cold more than heat. And most energy consumption in region is for heat supplying. Presentation of a climatic classification system on the basis this parameters that separate the regions to different thermal requirements.

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Three Dimensional Modeling of Laminar Air Flow Conditioning System with Air Curtain in Surgery Room

Mohammad Mehdi Keshtkar 1, Aslan Ashtiani 2

1 Assistant Professor , Mechanic Engineering Faculty , Islamic Azad University , Kerman branch ;

[email protected] 2 Bachelor’s degree student , Mechanic Engineering Faculty , Islamic Azad University , Kerman branch ;

[email protected]

ABSTRACT

he most important risks in surgery room environment which can be indicated are the contact of contaminants and floating particles with patient body and entrance of anesthesia gasses to the

outside of surgery environment. These can be reduced to least by creating a proper air conditioning system. In this article, the laminar air flow conditioning system with air curtain in surgery room and its advantageous compared with customary systems and without air curtain were investigated. The Computational Fluid Dynamic was applied for modeling and investigating the efficiency of this air conditioning system. In the preformed three dimensional simulations, the air entered the room with definite velocity and temperature, and the modeling was performed by flowing the air from ceiling to floor and creating positive pressure which is the necessity of a proper air conditioning system to prevent gathering of contamination concentration of surgery room. The air flow distribution, in two different ways, was compared by Fluent software. Using air curtain makes the surgery room air conditions close to safe and desired conditions and plays important role in reducing surgery room contamination. Keywords: Surgery room air conditioning, Computational Fluid Dynamic, Laminar flow, Air curtain, Three dimensional.

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Experimental Study of Thermal Comfort of an Automobile Driver’s Hands with Ventilated Steering Wheel

Babak Rafie Nia1, Mehdi Zare2, Gholamreza Karimi3

1B.S of Chemical Engineering, Shiraz University; [email protected]

2B.s of Chemical Engineering, Shiraz University; [email protected] 3Associated Professor of Chemical Engineering, Shiraz University; [email protected]

ABSTRACT This paper investigates the thermal comfort condition of driver’s hands in contact with a ventilated steering wheel, under hot summer conditions. A perforated steering wheel was designed and manufactured and ergonomic study was conducted with the help of a group of 10 participants. The new simulation method optimized the effects of passing air through steering wheel and convection heat transfer to reduce the time needed for approaching a stable and comfort conditions for driver’s hands. Air at different flow rates and temperatures was blown through the steering wheel and the participant’s thermal comfort was recorded using a questioner. Experimental results have indicated that air temperatures of below 10 ̊C to 5 ̊C and air flow rate of above 45 l/min to 50 l/min provide an appropriate thermal comfort. Keywords: Thermal Comfort, Ventilated Steering Wheel, Ergonomic Study, Air Temperature, Air Flow Rate

Industrial/Professional Applications Results of the article and the design of ventilated steering wheel can be applied in vehicles under hot summer and cold winter conditions to prepare suitable conditions in long period driving for the driver. Base on the high effectiveness of the new mentioned technology in this article on driving conditions and comfort of driver, this technology can increase the enthusiasm of customers intensely. Because of the special design of this steering wheel, using and applying this technology does not need to change in assembly line in car factories and this system can use the previous air condition system of the vehicle.

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Investigation of the Role of Outlet Position and Sitting Location on Thermal Comfort and Inhaled Air Quality for a Room with Stratum Ventilation

G.R. Molaeimanesh1

1 Ph.D. Candidate, Mechanical Engineering School, Shiraz University

ABSTRACT

tratum ventilation is a new ventilation method which can assist reducing energy consumption and also result in cost saving. In fact applying stratum ventilation method is the main option for

reducing energy consumption of ventilation systems in near future. In this method, ventilation of only a stratum of indoor space in which occupants’ head and chest is located is pursued. This is realized by positioning supply terminal(s) at the side-walls or columns slightly above the height of occupants. Although the supply air temperature for stratum ventilation is higher than that of conventional ventilations, the distance between the occupants and the air terminal is shorter, which results in reverse temperature gradient in the occupied zone, higher air speed for the same air supply rate, energy saving by avoiding over-cooling of the lower zone of a room and higher coefficient of performance (COP) for the associated refrigerating plant. In this study 9 stratum ventilated cases with a manikin sited behind a desk and with different manikin’s sitting locations and outlet positions are numerically modeled. For investigating the effects of sitting location and outlet position on thermal comfort and inhaled air quality, four evaluation indexes are computed for each case which are mean effective draft temperature, ventilation effectiveness, relative efficiency and NSIAQ. The results show the great influence of these parameters. Some important results which can help improving design and performance of stratum ventilation systems are as below: (a) When the outlet is positioned at the right wall and the manikin sited near inlet the mean EDTS is the worst. (b) When the outlet is positioned at the ceiling the ventilation effectiveness is more than others because the lamps at the ceiling can be cooled more effectively. (c) When the manikin is sited near inlet, the inhaled air quality is better because the age of the air is less. (d) When the outlet is positioned at the left wall the relative efficiency is more than others because the air has more chance to sweep

2CO out of office.

Keywords: stratum ventilation, thermal comfort, inhaled air quality, outlet position, sitting location.

Industrial/Professional Applications Applying stratum ventilation method is the main option for reducing energy consumption of ventilation systems in near future. It has been demonstrated that stratum ventilation is able to provide good indoor air quality in breathing zone and to achieve good thermal comfort measured by PDD and PMV. The results of this study show that when the outlet is positioned at the ceiling the ventilation effectiveness is more than others because the lamps at the ceiling can be cooled more effectively. When the outlet is positioned at the left wall the relative efficiency is more than others because the air has more chance to sweep

2CO out of office.

When the manikin is sited near inlet, the inhaled air quality is better because the age of the air is less.

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Energy Optimization

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Novel Energy Demand Side Management Practices and Cooling Load Reduction in Office Buildings Case Study: National Iranian Drilling Company New Building

Complex

M. Afshar1, S. M. H. Nabavi2

1 Petroleum University of Technology; [email protected] 2 Senior Expert; Tahvieh Nia Company, [email protected]

ABSTRACT

n this paper, novel energy Demand Side Management practices in an office building complex are investigated and the results obtained for a typical complex are presented. These DSM practices,

without interrupting the favorable building conditions, reduce the demand, and as a result will decrease the cooling load and running and maintaining related equipment costs; therefore it is vital to identify, design and implement these practices. Considering that the building complex investigated is relatively new, and the known DSM practices are already implemented, it is a good opportunity to investigate advanced DSM practices, here. Specifically, four new novel DSM methods in building complexes, namely: hybrid absorption-compression refrigeration systems, development and implementation of cooling schedule, green roof and walls, and smart control of chiller room facilities are investigated with the use of real climate, environment, architecture and equipment data and software simulation calculations. Related costs and return on investment period from reduction of demand and cooling costs are determined. The results indicate a 50% decrease in cooling demand is feasible. Keywords: Building Complex, Energy Demand Side Management, Renewable Energy, Cooling

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Experimental Investigation of Resulted Energy Saving in an Hybrid Air Conditioning System, Using of Desiccant Filter and Heat Pipe Heat Exchangers in Series

S. Khayami1, S.M. Nowee2, N. Monirimanesh3, A. Okhovat4

1M.Sc student, Ferdowsi University of Mashhad; [email protected] 2Asistant Professor, Ferdowsi University of Mashhad; [email protected]

3M.Sc student, Ferdowsi University of Mashhad; [email protected] 4M.Sc student, Ferdowsi University of Mashhad; [email protected]

ABSTRACT

owadays, energy consumption for the purpose of air conditioning in buildings is increasing and this issue caused that the air conditioning industry encountered with different problems, such as:

more need to increase energy consumption efficiency, the air quality improvement of conditioned space, the cost increasing of electricity consumption in peak times etc. New methods are being defined for solving these environmental and economical problems. Among the best methods are desiccant cooling and dehumidification. Another means is the use of heat pipe heat exchangers (HPHX) due to lack of need to any moving part or other energy resources for heat transfer from a heat source to a heat sink. An apparatus used in this study was designed and constructed for the purpose of decreasing energy consumption in air conditioning system to be used in hot and humid climates. This apparatus includes two HPHXs (in series) with two rows and the staggered arrangement of thermosyphones and methanol as the operating fluid, desiccant filter (with 3A molecular sieve as desiccant) and a split type of vapor compression system. The experiments were performed for investigation of system capability for using in hot and humid climate. For this purpose, 4 types of hot and humid climate, A (35oC, 90% RH), B (40oC, 80% RH), C (45 oC, 75% RH) and D (50 oC, 65%RH) were studied. Because of an increase in inlet air latent heat and a released adsorption heat due to increased moisture adsorption for case A to D, the total energy saving ratio decreased from 0.35 to 0.25. Also due to an increase in driving force of moisture adsorption from A to D, the energy saving ratio increased from 0.08 to 0.24. In addition, for the case without desiccant filter in this system caused improvement in HPHXs performance with respect to the case with no use of desiccant filter. Keywords: Air conditioning system, Hot and humid climate, Heat pipe heat exchanger, Desiccant filter, Energy saving.


Results analysis of this study indicates that the above system, have the capability for usage in different types of hot and humid climate. This study presents an acceptable energy saving ratio for all mentioned cases. The new mentioned technology could be used as an economizing air conditioner.

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The Effectiveness of Intelligent Controlling Chilling System and Controlling System of Radio Frequency of Fan Coil in Optimization of Electric Energy Consumption and Separation of Time

from the Load of Electric Network in Peak Time of Consumption

Touraj Bat’hayi, Seyed Mahdi Taherie

Expert of Fluid Mechanics, Pishrun Energy Company

ABSTRACT In buildings where chilling system is compression and thermal terminal is blower, these equipments are allocated a major rule of electric energy consumption which a significant part of, goes to waste in form of energy losses. Although there are different factors in waste of electric energy in working time of these equipments but the most important factor in intensification of this situation, is the kind of regnant controlling system on these equipments. As we know the most common used controlling system of compression chillers in our country is the thermostat kind that at the beginning of warm period of the year is arranged by an operator on a constant number even lower than norm, and in during of this period controls turning off/on of compressors with a constant process. This kind of controlling method has bugs even from the view of 19th subject of National Building Regulation and in most times causes in ineffective function of compressors and waste of electric energy in building. Thermostat controlling system not only doesn’t have the ability of automatic changing of capacity of chiller according to changes of temperature of weather but also in buildings which have terminated usage there’s no ability to define a time schedule according to work hours of the building in each and every day of week. The most effective solution to achieve these goals is using intelligent controlling chilling system. This system leads off all the equipments of chilling engine room according to the changes of the temperature of weather till the comfort condition is reached. Also in buildings equipped with fan coils, weaknesses of control existing in these equipments have caused in to let the control to be completely in user’s hands and to be according to his/her taste and also after finishing work hours because of lack of attention of the user, these equipments will be staying on and while ineffective usage of electricity cause in forcing an extra amount of load to chiller or hitter engine room and extra waste of energy in building. So, in order to correct this situation and optimization of electric energy consumption, the best solution is the usage of Radio Frequency controlling system. This system is installed in an appropriate place in building and with sending radio information with an exclusive code for receiver serried in the way of the electricity of the fan coil, controls the fan coils separately and according to prearranged time and temperature schedule. Keywords: optimization of electric energy consumption, Central cooling intelligent controller, Radio Frequency controller of Fan Coil

Industrial/Professional Applications The intelligent controlling chiller system has Persian menu, solar calendar and is adaptable to thermal physics of the available buildings in the country and the quality of designed chiller engine room. The intelligent controlling chiller system leads off all the electric equipments in chiller engine room like compressors (in all kinds and powers), chilled water pumps and pumps and the fans of cooling tower with an adaptable logic. The intelligent controlling chiller system reduces 25% of the consumption of electric energy and consumption of chilling tower water, in full time buildings and 50% in terminated used buildings. Radio controlling system has the ability to control 500 electric equipments in building such as fan coils, Split cooler, lights and other electric equipments without the need of cabling and through sending frequency and separately.

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Methodologies for Optimization the Energy Consumption in Design and Construction Process and Experimental Test in the Sample Building

Seyyed Javad Mohammadi Baygi, Saeed Rajabinasab, Robabeh Jazayee

1 Assistant professor, Damghan Branch, Islamic Azad University, Damghan, Iran; [email protected]

2 B.S.C student, [email protected] 3 M.S.C., [email protected]

ABSTRACT

eating and cooling account for about 56% of the energy use in a typical home; making it the largest energy expense for most homes. A wide variety of technologies are available for heating

and cooling the home, and they achieve a wide range of efficiencies in converting the energy sources into useful heat or cool air for the home. When looking for ways to save energy in the home, be sure to think about not only improving the existing heating and cooling system, but also consider the energy efficiency of the supporting equipment and the possibility of either adding supplementary sources of heating or cooling such as design construction and climate. Different strategies for optimizing the energy consumption in the buildings and the successful approaches for the use of heating and cooling systems to reduce the energy consumption in the building without loss of thermal efficiency are discussed at this paper. These approaches are categorized in to different instructions. The ground selection process, the inside and outside building design and architecture, the methodologies to reduce the windows contribution in energy consumption, the local climate condition, use and effects of natural vegetation, the wall and roof and floor insulation, the methodologies to reduce the energy consumption in the heating and cooling system etc. Then the solution of practical systems, the infloor heating system and double glazing windows in the building, has been assessed. At first the energy consumption in the sample building in the condition of normal windows and normal heating and without the infloor heating system has been studied. In the different strategy, the infloor heating system is operated and the energy consumption in the building has been recorded. Then, in the other strategy, the double glazing windows are replaced and the energy consumption in the building has been recorded in the condition of heating with and without the infloor heating system. The results show that, the energy consumption in the sample building, with the infloor heating system and the normal windows is 36 percent lower than the energy consumption with the normal heating and the normal windows. The results also demonstrated that the energy consumption in the sample building with the infloor heating and the double glazing windows is 52 percent lower than the energy consumption in the building with the normal heating and the normal windows. Keywords: optimization, conditioning system, infloor heating, double glazing windows

Industrial/Professional Applications The infloor heating system reduces the heat consumption in the building. The double glazing windows reduce the heat consumption in the building. The use of both technology in this article (the infloor heating and the double glazing windows) reduce the energy consumption in the building at about 52 %. The insulation of the building will reduce the energy consumption.

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Application of Renewable Energies

in HVAC&R

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Three-Dimensional Simulation of Cooling System Using Solar Chimney and Underground Wet Channels

Ramin rabani1, Vali kalantar2, Mehrdad rabani3, Mehran rabani4

1 M.S. student, Yazd University; [email protected]

2 Assistant of professor, Yazd University; [email protected] 3 M.S. student, Yazd University; [email protected]

4 Ph.D. student, Yazd University; [email protected]

ABSTRACT

n this paper, the natural cooling of a room by using solar chimney, underground wet channels and the absorbent walls with radiation and water injection system simulated. The turbulence model and

radiation model is used to calculate the buoyancy forces and radiation respectively. This way for the sun-rich and hot and dry towns (Yazd) is very effective. Using water spray system in inlet vents is cause to adequate humidity and temperature requirements for interior space of room. Current study includes evaluation of system performance in steady state and effect of parameters such as temperature of entrance air, the amount of injected water and heat flux on the flow field, temperature and relative humidity. Results obtained in the form of graphs of temperature, relative humidity and velocity in the different sections; also amount of the ACH in the room and contour of temperature and relative humidity are presented. Keywords: Solar chimney, Underground wet channels, Radiation model. Industrial/Professional Applications • The use of solar and evaporative cooling system is an effective cooling way of residential space in warm and dry regions. • Use of cooling system with underground wet channels reduces water consumption about 55% and power consumption about 80%. • Because of passive system performance, solar cooling system is without any noise and is appropriate to use for quiet environments such as hotels, educational and residential places. • Depreciation of this system is low and cost of maintenance is low and affordable.

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Theoretical & Experimental Analysis of a Flat Plate Solar Collector

A. Asadzadeh Zargar1, F. Jafarkazemi2

1M.Sc. in Energy Conversion, Mehrtab Energy Co.; [email protected]

2Assistant Professor, Islamic Azad University, South Tehran Branch; [email protected]

ABSTRACT

egarding to limitation in fossil fuel resources and also caused damage in the case of non-normative use of them to the environment, researches on use of renewable energy are of great

importance. Since solar energy is clean and free from contamination and solar energy potential is high in Iran, it is extremely important. There have been many different ways to use this clean energy. But water heating by solar heaters has been known as an easiest and the most economic way. We can easily and effectively use solar energy to heat water at home or even in industry if we have gained adequate knowledge about solar radiation. The purpose of this article is to compare between theoretical analysis and practical results of the test on a flat plate solar collector. In order to do this, firstly a collector has been theoretically modeled with using heat transfer relations, and then it has been practically tested with the assistance of equipments existing in Solar Energy Research Center in Islamic Azad University, South Tehran branch based on ISO 9806-1. The result of the experimental test and theoretical model were compared. Regarding to the tests done, it can be said there has been an appropriate adaptation between theoretical and experimental models. These experiments were all done at different flows. It is concluded that any decrease in fluid flow through collector has caused increase in efficiency and useful energy gained. According to experiments done, the maximum efficiency for a flat plate solar collector could be achieved when the collector inlet water temperature is close to the ambient air temperature. Keywords: flat plate collector, test, efficiency

Industrial/Professional Applications Constructing a Solar Energy Research Center and weather station in order to record the climate condition of Tehran in Islamic Azad University, South Tehran branch. Regarding to the tests done, it can be said there has been an appropriate adaptation between theoretical and experimental models and this site can be used to test other sorts of solar collectors. To access the maximum efficiency for a flat plate solar collector, the collector inlet water temperature should be as close as the ambient temperature.

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Design and Simulation of Solar Assisted Single Effect Absorption Chiller for Tehran

Mohammad Reza Majdabadi1, Cyrus Aghanajafi2

1M.Sc.Student, Islamic Azad University-South Tehran Branch; [email protected] 2Associate Professor, Faculty of Mechanical Engineering K.N.Toosi University of Technology;

[email protected]

ABSTRACT

aying attention to increase of consumption and also price of energy in Iran and of course environmental pollution caused by traditional fuels, results in using renewable energies beside the

fossil fuels, seems to be more necessary in these days. One of the high potential of these sources of energy in Iran is solar energy and can be used as a clean and available source in cooling systems. According to need of the temperature of hot water as low as 85 to 90ºC, single – effect absorption chiller can be a good choice for this application. In this article, solar radiation conditions of Tehran were the base of design and simulations. If a 5 ton of refrigeration single effect absorption chiller coupled by 48 m2 flat plate solar collector in south direction With a tilt of 20 degrees and a 1400 liters reservoir, 55% energy saving and 70% economical benefit Can be achieved in summer for Tehran. Keywords: Solar Cooling, Solar Chiller, Simulation

Industrial/Professional Applications Solar absorption systems have many advantages when compared to vapour compression systems (conventional electrical systems). On the other hand, incidence of solar energy and cooling demand are approximately in phase. Solar single- effect absorption chiller due to the use of low temperature hot water is the best solar cooling technology for temperate climate region such as Tehran. If a 5 ton of refrigeration single effect absorption chiller coupled by 48 m2 flat plate solar collector in south direction With a tilt of 20 degrees and a 1400 liters reservoir, 55% energy saving and 70% economical benefit Can be achieved in summer for Tehran.

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Simulation and Exergy Analysis of Solar Lithium Bromide Single Effect Absorption Chiller

Mohammad Reza Majdabadi1, Cyrus Aghanajafi2

1M.Sc.Student, Islamic Azad University-South Tehran Branch; [email protected]

2Associate Professor, Faculty of Mechanical Engineering K.N.Toosi University of Technology; [email protected]

ABSTRACT

ccording to the high Solar radiation potential of the country, using an appropriate solar sorption cooling system can cause energy and economical preservation. In the present work, a solar single

effect absorption LiBr chiller with the capacity of 17.5 kW simulated for using in Tehran and then first and second law of thermodynamics were analyzed by programming in EES. By this analysis, operating power of cycle in different conditions and parameters can be evaluated and optimum temperature of importing hot water, irreversibilities, system thermal ratio and first law and exergy efficiencies in various hours can be calculated. On the basis of results, solar collectors, absorber and generator of chiller have a portion about 53%, 19% and 6% of whole exergy destruction, respectively, which the most losses of the system occur in them. Keywords: Absorption Chiller, Solar Cooling, Exergy Analysis

Industrial/Professional Applications Using solar lithium bromide absorption chiller in regions with temperate climate can be a good alternative to electrical conventional systems According to first and second law of thermodynamic analysis, the optimum input hot water temperature for the desire system is 85°C.Cofficient of performance in this state is 0.7 Solar collector, absorber and generator of chiller have most losses of the system and should be more careful in designing them to increase exergy efficiency

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Exergy Analysis of GSHP with Low Temperature Source

Seyed Mehdi Monsef Rad1, Kourosh Javaherdeh2

1 faculty of mechanical engineering, Islamic Azad University, Takestan branch, Takestan, Iran, [email protected]

2Faculty of mechanical engineering, University of Guilan, Rasht, Iran, [email protected]

Abstract

his article presents a comprehensive exergy analysis of every single partition and the whole system of two GSHP systems using low temperature resources. First pump uses geothermal health

resort centers and the second uses heat from depth in the ground as recourse. It presents analytic formulas for indexes exergy loss, exergy efficiency, exergy loss ratio, exergy loss coefficient and thermodynamic perfect degree for every single partition and the whole systems in the heating mode. The results indicate that for a comprehensive exergy analysis these indexes must be used integratively. In addition, the final results indicate that in the whole system of both GSHP systems compressor is the location of maximum exergy loss, exery loss ratio and exergy loss coefficient and minimum of exergy efficiency and thermodynamic perfect degree. Therefore, compressor is the first partition which must be improved. Finally it has shown that exergy efficiency for the whole GSHP system is obviously smaller than it’s every single partition.

Key words: Geothermal heat pump (GSHP), Exergy indexes, Heating, R-22


Using low temperature resources results in saving of Fossil fuels. Using geothermal health resort centers results in better efficiency and prevents destruction of natural resources. Choosing a better compressor could be a device to obtain a better efficiency from a GSHP. The results of this article could be used for design a new residential space heating way.

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Exergy Analysis of a Solar Ejector Refrigeration System during a Day

Hesamodin Salarian1, Hooman Golchoobian2, Bahram Ghhorbani2, Majid Amidpour2

1Department of Mechanical Engineering, Islamic Azad University, Nour, Iran 2Department of Mechanical Engineering, K.N. Toosi University of Technology, Tehran, Iran

ABSTRACT

jector refrigeration system is a thermally driven technology that has been used for cooling applications for many years. In their present state of development they have a lower COP than

vapour compression systems but offer advantages of simplicity and no moving parts. Their greatest advantage is their capability to produce refrigeration using waste heat or solar energy as a heat source at temperatures above 80°C. In present work, a dynamic model is proposed for use in investigating the exergy analysis of a solar ejector refrigeration system using R134a, for office air conditioning application in Tehran. Classical hourly outdoor temperature and solar radiation model in a typical summer day were used to provide basic data for analysis. The exergy analysis of the solar-driven ejector refrigeration system was performed assuming the following conditions. Evacuated tubular solar collector is used. R134a is used as the refrigerant for the refrigeration cycle. Water is used as the heating medium between the solar collector and the generator. The cooling capacity is 5 kW. The generating temperature is 85°C. The condensing temperature is 35°C. The evaporation temperature is 8°C. The pump efficiency is assumed to be 25%. The total efficiency of the ejector is assumed to be 70%. The results show that dynamic analysis is confidently more useful than analysis in a constant condition. This method is more completed because it can present the efficiency of the components of the system at each time. As the results present components have different efficiency at different time. The most irreversibilities in the system occur in solar collector with 52% and ejector is in the next step. Moreover during the office working-time, i.e., from 8:00 to 16:00 and irreversibilities in components change considerably. The first and the last hours of working time have greater irreversibilities. At the end, some suggestions are presented to increase the efficiency of the system. Using self adjusting solar collectors can help to reduce high irreversibilities in collector. In addition using storage tank can save solar energy for the evening hours and let us eliminate some panels of collectors from circuit to decrease irreversibilities and increase exergy efficiency of the system. Keywords: dynamic exergy analysis, solar ejector refrigeration system, irreversibilities

Industrial/Professional Applications Solar ejector refrigeration system will be increase the use of renewable energy in HVAC&R. Ejector refrigeration system offer advantages of simplicity and no moving parts and using waste heat or solar energy as a heat source. Dynamic exergy analysis is confidently more useful to show irreversibilities than analysis in a constant condition.

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Analytical and Numerical Investigation of Influence of the Absorber Plate Position in a Solar Chimney

F. Shamsizadeh1, V. Kalantar2, A. Dehghan3

1MA Student, Yazd University; [email protected]

2 Assistant Professor, Yazd University; [email protected] 3 Associate Professor, Yazd University; [email protected]

ABSTRACT

he solar chimney concept used for improving room natural ventilation is analytically and numerically studied in steady state condition. The study investigates the effect of changing

absorber plate position, on ACH and flow pattern, in both single and double pass solar chimneys with specified geometry. Moreover, performance of the chimney is studied in Yazd weather. Flow is first studied analytically; Then boundary conditions for numerical solution is set according to the analytical solution results. The steady, laminar, incompressible and two-dimensional form of the equations of continuity, momentum and energy is solved for the fluid flow in the solar chimney using the Boussinesq approximation. Non-dimensional form of the equations is solved by finite volume method. SIMPLER algorithm is adopted for pressure-velocity coupling and pseudo-transient approach is used. It is also assumed that viscous dissipation is neglect able. The governing equations have been solved analytically and numerically by setting two Fortran codes. Finally, it is found that air change per hour (ACH) for double pass solar chimney is higher than that of the single pass one by at least 40.9% and at most 76.2%. Results show that ACH first increases and then decreases while absorber distance from glass wall increases. It is observed that for investigated chimney, maximum ACH occurs when distance of absorber plate from the glass reaches to 0.12 m, when created eddies and wall dissipations become at least. Moreover, results show that air temperature increases while increases height from the bottom of chimney, especially near the absorber plate, glass and insolated (just in double pass chimney) walls. Air velocity is also increased near those walls. Keywords: solar chimney, natural ventilation, double pass chimney

Industrial/Professional Applications Researches show that about 30% of energy consumption is relevant to town buildings and about half of it, is used for environment heating and cooling; so solar chimney usage causes significant decrease in energy consumption, in hot and dry zones of the country. According to the investigations, solar chimney performance in double pass one is much better than single pass. ACH for chimney with investigated geometry, in double pass one is increased at least 40/9% and at most 76/2% respect to single pass chimney.

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Experimental Study on Compatibility of Heating Application of Geothermal Energy in Ardabil City

M. Rahimi1, H. Gholami Sormoli2

1Associate Professor, University of Mohaghegh Ardabili; [email protected]

2Msc Student, University of Mohaghegh Ardabili; [email protected]

ABSTRACT

he compatibility of using geothermal energy in heating of different spaces in Ardabil city, where has an excessive geothermal potential, was examined at the present study. Flexible Water pipe of

100 m length and 16 mm diameter in helical form was buried at the depth of 4 m under the ground surface within a conduit having 8 m length and 0.7 m wide. Water at a very low temperature (almost 0˚C) was pumped into the pipe. Returning flow from the pipe was cooled again and re-circulated through the pipe for extracting geothermal energy. Inlet and outlet temperature of the water as well as underground temperature at different depths were measured and recorded using a temperature data logging system. Mass flow rate of the flow was also specified using a graded vessel and a chronometer. Based on the results of the study, underground temperature of the experimented area at 4 m depth was about 12˚C which remained fairly constant. Underground temperature close to the ground surface was strongly affected by the environmental parameters such as wind velocity and sun radiation. The temperature was raised as the depth under the ground surface was increased but the slope of the temperature increment became very low for depths greater than 2 m. Under steady condition, geothermal energy of about 1700 W was extracted using the specified uncomplicated system from a small enough region of the ground. It should be mentioned that the extracted energy could not be directly used in heating of spaces due to the low temperature of the geothermal energy source and a heat pump would be applied in transferring the energy into the heating space. Keywords: Geothermal energy, Heating


Underground temperature is not affected by the environmental parameters at depths greater than 1 m. Temperature increment slope becomes very low for depths greater than 2 m. Water pipe of 100 m length and 16 mm diameter buried at 4 m underground at a small area could extract about 1700 W geothermal energy under experimented circumstances.

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Parametric Study of an Indirect Solid Oxide Fuel Cell-Gas Turbine Hybrid System Performance from Exergy Viewpoint

Jamasb Pirkandi1, Majid Ghassemi2, Mohammad Hossein Hamedi3

1Faculty of Mechanical Engineering; K.N. Toosi University of Technology; [email protected]

2Faculty of Mechanical Engineering; K.N. Toosi University of Technology; [email protected] 3Faculty of Mechanical Engineering; K.N. Toosi University of Technology; [email protected]

ABSTRACT

he objective of this research is to present a thermodynamic model for an indirect hybrid system of gas turbine and fuel cell, and to analyze it from the energy, and then exergy, viewpoint. The

modeling of each component of the cycle is such that the input and output flow conditions in them are specified and the interactions of these cycle components on one another are also considered. In this research, the flow rates of air and fuel entering the system as well as the compressor working pressure ratio have been considered as the three major parameters that affect the performance of the said hybrid system. An examination of the hybrid system’s performance indicates that with the increase of the working pressure and rate of air flow into the system, due to the reduction of cell temperature, the efficiency of the system diminish, and irreversibility rate in the system are increased. Keywords: indirect hybrid system; irreversibility; exergy; gas turbine; solid oxide fuel cell Industrial/Professional Applications The ability of the solid oxide fuel cells in being combined with different power generating systems has made the resulting hybrid systems to be regarded as new energy producing sources. The high quality of SOFC in heat generation makes it very suitable for using in the CHP systems. One of the most frequent applications of solid oxide fuel cells in power generating systems is their combination with various types of gas turbines Generally, the gas turbine cycle can be combined with a solid oxide fuel cell through the direct method (D-SOFC-GT) or the indirect method (IND-SOFC-GT) The increase of the system working pressure leads to the decrease of electrical efficiency and increase in the irreversibility rate of the system. The increase of the flow rate of air passing through the system, due to its cooling effects, weakens the performance of the system. The increase of the fuel flow rate into the system, due to increasing fuel cell temperature, cause to growth of electrical efficiency and irreversibility rate of the system.

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3D Numerical Simulation of a Flat Plate Solar Collector and Investigation of Effective Parameters on Collector Operation in Dry Climate

Fateme erfani1, vali kalantar2

1 M.Sc. Student, Mech. Eng., Yazd University; [email protected]

2 Prof. of Mech. Eng., Yazd University; [email protected]

ABSTRACT

he objective of this work is to simulate a flat plate solar collector in 3d and unsteady mode. Numerical analysis is modeled solar radiation on the collector and internal radiation model from 9:00 a.m. To

4:00 p.m. Also heat transfer is simulated in the water and air flow for warm/dry climate of Yazd city. Water heating system is designed in one tube scale and water circulation is modeled between collector and storage tank. The considered case includes the CFD modeling of solar irradiation and the modes of mixed convection and radiation heat transfer between tube surface, glass cover, side walls and insulating base of the collector as well as the mixed convective heat transfer in the circulating water inside the tube and conduction between the base and tube material. After 3D unsteady numerical simulation, temperature distribution over the collector was studied. According to the Ra number, flow regime is laminar. Calculations with CFD model elucidate the flow and temperature distribution in the collector. As a result, temperature distribution is investigated in the outlet of collector. The purpose is increasing in the temperature of working fluid. It is shown that, temperature of working fluid in the outlet of collector is increased 28 degrees and temperature of storage tank was 45°C. The influences of different condition such as collector tilt angle and working fluid are shown. Also double glazing cover is studied in this work. It is shown that double glazing cover increases temperature of working fluid and efficiency of collector. Also using of cooper absorber plate is increased efficiency of the collector. It is shown that the collector panel with a tilt angle of 30 degree is the best choice for climate condition of Yazd city. Then it can be seen that water and propylene glycol as a working fluid, almost have the same temperature at the end. Finally numerical calculations are compared to the experimental data and there is a good agreement between numerical and experimental results. All the research in this article will be increase the use of solar energy and so saving more electric energy and oil consumption. Keywords: flat plate solar collector, water heating system, natural convection, radiation model.


A solar water heating system is designed for warm/dry climate and it is shown that using of cooper absorber plate increases efficiency of the collector. It is shown that the collector panel with a tilt angle of 30 degree is the best choice for climate condition of Yazd city Solar water heaters are not only environmental friend they can be cost efficient over the life of the unit with the savings made from the conservative use of power.

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Transient Simulation of a Solar Stratified Storage Tank for Using in Solar Cooling System

Mohammad Rezai Firozjaei 1, Majid Bazargan 2, Majid Amidpour 3

1MSc student of K. N. Toosi University of Technology; [email protected]

2Associated professor of K. .N. Toosi University of Technology; [email protected] 3Associated professor of K. N. Toosi University of Technology; [email protected]

ABSTRACT

olar storage tank is one of the most important parts in solar HVAC systems. The efficiency of these systems is strongly influenced by the performance of the tanks. However, in solar heating

and solar domestic water heating systems, tank is used to store energy for increasing the systems efficiency otherwise, in solar cooling system, due to the effect of water temperature on the coefficient of performance (COP) and adaptation between solar energy variation and building cooling demands, the tank is used for damping temperature fluctuation and supplying high temperature water for solar cooling system. In this study, the thermal behavior of a solar stratified storage tank with coil heat exchanger is modeled. The tank performance for application in Karaj city has been simulated and the temperature profile has been calculated by solving the governing equations under transient conditions. The results have been used to propose the best configuration of coil heat exchanger in the tank in order to achieve maximum system COP. Keywords: energy storage, solar stratified storage tank, solar cooling.

Industrial/Professional Applications Results of the article can be applied in design of new optimum and cost effective solar storage tank for solar cooling systems. A computer code which is developed for this article can be used for analyzing of solar HVAC systems performance and calculating of system efficiency. A computer code is developed for calculation of hourly solar radiation data for different climates and regions.

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Design of a Solar Cooling System Based on Adsorption for an Office Building in Tehran

Farzad Rezvani1, Amir Farhad Najafi2

1Master Student, Power and water University of Technology; [email protected] 2Associated professor, Power and water University of Technology; [email protected]

ABSTRACT

n this research, primarily, needs and energy consumption of an office building with 927 m2 conditioned area simulated and for meeting cooling needs, adsorption cooling system has used

which was modeled with TRNSYS software. The reason for applying adsorption cooling compared with other solar cooling technologies is the low driven temperature (50-85 ). To enhance the economic feasibility of solar cooling system, assuming no simultaneous heating and cooling, parts of heating needs has been supplied through this solar system. According to calculations, for saving 47% annual cooling and heating energy (49231 kWh), this building needs 99.6 m2 flat plate collectors witch the average solar fraction (the ratio of solar energy used in the whole system divided by the total energy requirement of the solar cooling plant) will be 0.62. Finally the Hourly temperatures for different parts of the solar cycle investigated that results showed the proper performance of adsorption cooling for meeting the requirement of the 80 kW adsorption chiller. Keywords: Solar cooling, Adsorption chiller, flat plate collector

Industrial/Professional Applications With changing tilt of collector in 3 angles of 20, 35 and 50° in different times of year for Tehran (for example 20° for cooling purpose), the received irradiation on the collector plane can be enhanced about 10% and as a result we will need less collector area for producing energy to drive the adsorption chiller. Solar adsorption cooling systems need lower driven temperature compared with other solar cooling technology. In our case we reached to COP of 0.6 for silica-gel/water as the adsorbent/adsorbate with driven temperature of 70 . Because of low driven temperature in adsorption cooling (in our case 70 ) it is possible to use less expensive flat plate collectors instead of for example evacuated tube collector and as a result we can achieve reduction of overall cost. In this case with using 99.6 m2 flat plate collector, we saved about 47% of primary energy consumption. Using Adsorption solar cooling system are a proper choice for meeting the cooling needs of office buildings with daily work hours. In our case, we saved about 49231 kWh of yearly primary Energy use with average annual solar fraction of 0.62.

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Financial Analysis of Using a Solar Cooling System Based on Adsorption for an Office Building in Tehran

Farzad Rezvani1, Amir Farhad Najafi2

1Master Student, Power and water University of Technology; [email protected]

2Associated professor, Power and water University of Technology; [email protected]

ABSTRACT

n this research, primarily, needs and energy consumption of an office building with 927 m2 conditioned area simulated and for meeting cooling needs, adsorption cooling system has used

witch it was modeled with TRNSYS software. The reason for applying adsorption cooling compared with other solar cooling technologies is the low driven temperature (50-85 ). To enhance the economic feasibility of solar cooling system, assuming no simultaneous heating and cooling, parts of heating needs has been supplied through this solar system. According to calculations, for saving 47% annual cooling and heating energy (49231 kWh), this building needs 99.6 m2 flat plate collectors witch the average solar fraction (the ratio of solar energy used in the whole system divided by the total energy requirement of the solar cooling plant) will be 0.62. Finally the economic futures of system investigated and results showed after about 10 years, future value of money for solar and conventional (vapor compression) cooling system reached together and the payback time of investment will be about 13 years. Keywords: Solar cooling, Adsorption chiller, financial analysis, Payback time, Future value of money

Industrial/Professional Applications With changing tilt of collector in 3 angles of 20, 35 and 50° in different times of year for Tehran, the received irradiation on the collector plane can be enhanced about 10% and as a result we will need less collector area for producing hot water to drive the adsorption chiller and reduce overall cost. In this present time, using solar adsorption cooling systems is not economical but with assigning and adding parts of heating duty to the solar system (in this case 47%), we can enhance the economical points of view. With this method, in our case (office building with 927m2 conditioned area), after about 10 years, future value of money for solar and conventional (vapor compression) cooling system will reach together and the payback time of investment will be about 13 years. Because of low driven temperature in adsorption cooling (in our case 70 ) it is possible to use less expensive flat plate collectors instead of for example evacuated tube collector and as a result we can achieve reduction of overall cost. In this case with using 99.6 m2 flat plate collector with specific cost of 7200000 IRR/m2, we saved about 47% of primary energy consumption.

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Modeling the Performance of a Solar Heat Pump and Comparison with Conventional Heat Pumps

Misagh Moradali1 , Farzad Jafarkazemi2

1Msc in Mechanics; Mehrtab energy Co; [email protected]

2 Assistant Professor; Islamic Azad University; South Tehran Branch; [email protected]

ABSTRACT

t is the aim of this paper to analyze the thermodynamic performance of a direct expansion solar assisted heat pump (DX-SAHP) with flat plate solar collector. The investigated heat pump is intended to be used for water heating in a 150 liter tank by the condenser tubes inserted in the tank. Refrigerant used is

R134a, initial water temperature is assumed to be 20˚C and final water temperature is 45˚C. By thermodynamic modeling, effect of parameters such as solar radiation, and ambient temperature were investigated. Then the results were compared with a conventional heat pump based on catalogue data. One year performance of the solar assisted heat pump also compared with a conventional heat pump. According to the results, different parameters such as solar radiation, ambient temperature, collector area,… can affect the performance of solar assisted heat pumps. Increasing solar radiation, collector area and ambient temperature and decreasing water tank temperature increases the coefficient of performance (COP). COP, based on 45˚C tank temperature and 15˚C ambient temperatures at solar radiation levels of 450W/m2 and 950W/m2 are 3.4 and 5.5, respectively. A comparison between modeling of solar assisted heat pump and conventional heat pump shows that coefficient of performance for the former is higher than the later if there is adequate solar radiation available. Also, there is less variation in solar assisted heat pump COP in comparison to a conventional heat pump during the year. Yearly performance comparison of these two systems shows that the average COP of the solar assisted heat pump is higher than the conventional one. Keywords: heat pump, solar heat pump, solar energy, coefficient of performance


Decreasing the ambient temperature, decreases the COP of conventional air source heat pumps very sharply. There is little variation in solar assisted heat pump COP with variation in ambient temperature. Solar assisted heat pump can decrease energy consumption in cold climates of the country. The average COP of solar assisted heat pump varies between 6.23 and 6.8 during the year. The same values for a conventional air source heat pump are 3.4 to 6. In all cases using solar assisted heat pump is preferred to electric water heaters. Based on available solar radiation in cold climates/seasons, solar assisted heat pump can have the preference to solar water heaters, also.

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Performance Analysis of a Solar Li-Br Absorption System

E. Shokoohian1, M. Ameri2

1Master of Science. Student, University of Shahid Bahonar, [email protected] 2Associate Professor, University of Shahid Bahonar, [email protected]

ABSTRACT

n this paper, to investigate the new energy systems, solar study and analyzing numerical data using the EES software on the governing equations of solar energy systems are discussed. The absorption

performance of the system, the sun regarding the effects of lithium - bromide with flat collector and collector pipes are investigated. By using meteorological data (air, water and Kerman) the heat absorbed by the collector was calculated. The influence of various parameters such as the collector surface, the volume of water storage tanks, changing seasons, changing the angle of collector installed on the system performance is. Thus, this study found increased levels collector storage tank temperature, especially in the early hours of the start that this system will cause the system to start work earlier Keywords: absorption system, flat plat collector, vacuum tube collector

Industrial/Professional Applications The results obtained in this research can be applied to the industrial HVAC systems. Determination of collector and storage tank water volume due to weather conditions and the amount of radiation occurs. increase the water storage tank in a solar absorption system will cause the system stability Absorbed solar vacuum tube collector system with better performers in the same condition of absorbed solar collector system is flat. The vacuum tube collector system with a coefficient of performance will be better and more time can be used for solar energy Absorbed solar system with cooling tower solar absorption system for better performers in the same conditions with air condenser and solar energy can be used more time …

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Integration of Ground and Capillary Heat Exchangers for Cooling Greenhouse Food Production in Areas around the Persian Gulf

Hamid Reza Hooshangi1, Yoness Alizadeh2, Sepide Najafian3

1BSc student, School of mechanical engineering, Amirkabir University of Technology; 424 Hafez Ave Tehran

Iran. [email protected] 2Associate professor, Mechanical Engineering Dept, Amirkabir University of Technology; 424 Hafez Ave

Tehran Iran. [email protected] 3Engineer, Technical Manager of Gostareshan Company; [email protected]

ABSTRACT

he high solar irradiance, temperature and humidity in north of Iran makes the basic problem of cooling and ventilating of greenhouses in this hot and humid area. Because of this climate

condition, the efficiency of evaporative cooling systems is low and natural ventilation is impractical. This paper suggests and models the novel cooling system which transfers the heat of greenhouse to the ground. In north of Iran, the earth temperature in a depth of 4 meters is 18-20 centigrade and it usually insensitive to the diurnal cycle of air temperature and solar radiation. Heat of greenhouse is absorbed by water which circulates through the capillary heat exchanger, which is suspended from the walls of the greenhouse. Water absorbs the heat and then circulates in the depth of 4 meters and rejects the heat to the soil by horizontal ground heat exchanger. The proximity to the sea makes the soil of this region moist so thermal conductivity of soil is adequate for high efficiency heat exchanger (GHE) and eliminates the possibility of heat accumulation around the GHE. Energy consumed for cooling of greenhouse is low and related to the electricity consumption of water pump. This system keeps the air temperature of greenhouse under the 24 centigrade whereas the evaporative cooling systems cannot decrease the air temperature beyond the 31 centigrade. Keywords: Solar greenhouse, Cooling system, Capillary heat exchanger, Ground heat exchanger.

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Technical and Economical Analysis of Using Solar Energy in North Khorasan Gas Company’s Buildings

Pouria Naeemi Amini1, Yoones Bayat1, Mehdi Zamiri2 , Mahmud Hasanpoor Golriz1

1PhD Candidate, Ferdowsi University of Mashhad, Mechanical Engineering Department

2Manager of research department of North Khorasan gas company

ABSTRACT

owadays, using solar energy for heating, cooling or electrical power has become practical and has been used in many countries. In this research, technical and economical study of potentials of

using solar energy in north Khorasan gas company’s buildings has been conducted. First basics of solar energy reviewed. In this step, solar radiation, calculation of the receiving energy and the effect of geographical and geometrical parameters on the receiving energy proposed. Then, important geographical and meteorological parameters like, sun hours studied. For this purpose, meteorological data from NASA site was used. Then, electrical and gas bills of buildings, separately, were investigated. It is assumed electrical power was used for lighting, tools and cooling and gas was used for heating and hot water. In this step, collecting data were finished. Next, different applications of solar energy regard type and amount of consuming energy studied. Most common applications are: solar heating, photovoltaic, and thermoelectric. In the next step, technical and economical calculation of photovoltaic systems and solar heating systems was shown. Calculations of different components like, panel, battery, and collector were reviewed. After that, costs for buying and installation of photovoltaic systems and solar heating systems in each building with regard max, min, and average consumption were calculated. Finally, economical investigations of these systems and present factor value of using solar systems were studied. Keywords: Solar energy, Technical Analysis, Economical Analysis, Photovoltaic System, Solar Heating System.

Industrial/Professional Applications Results of the article can be used for studying of using solar energy in various buildings. Even after increasing of fuels’ prices in Iran, using of solar systems is not economical because of initial investment. Using of solar energy in new buildings is more economical. The first step in using solar power systems is optimal usage of energy, so it should be more emphasize on it.

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Professional Experiences

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Refrigerant Inventory Prediction in Refrigeration Equipment

Mohammad Ansari1, Ali Arianpur2, Farhad Asgharnia3

1 Mechanical Engineer, PHD Student, Sanaye Sarma Afarin Iran co.; [email protected] 2Mechanical engineering M.S., Sanaye Sarma Afarin Iran co.; [email protected]

3Mechanical Engineer, Sanaye Sarma Afarin Iran co.; [email protected]

ABSTRACT

efrigerant inventory, or charge, in refrigeration and air conditioning systems was investigated. Different models of two phase flow and heat transfer were studied. Refrigerant inventory is

essential for designing a new equipment, refrigerant retrofit and operation of existing equipment, methods and data needed to calculate refrigerant inventory are provided. To estimate refrigerant inventory in a system, refrigerant in every individual part must be considered, addition refrigerant in piping must be considered. Density of liquid refrigerant is significantly higher than vapor refrigerant. Therefore parts which contain liquid refrigerant are more important. Due to two phase flow in heat exchangers the prediction of refrigerant inventory is more complicated. To simulate refrigerant quality in length of heat exchanger, two methods are carried out. In first method refrigerant quality is considered to be homogenous and change linearly with heat exchanger length. Second method divided heat exchanger into several specific regions and each region was studied separately. Heat transfer coefficients are calculated for every region and the length of each region is calculated. Inside the phase change region, the quality is considered to vary linearly; therefore quality change is related to heat transfer coefficients of each region. Refrigerant inventory calculated from the first method was 20% more compared to experimental value of refrigerant charge. Second method obtained a more accurate result, and the difference was only 4%. Comparison of experimental data and result of theoretical calculation shows that the proposed method could be used with enough accuracy to calculate refrigerant charge in refrigeration equipment. Key words: refrigerant inventory, refrigerant charge, refrigeration.

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Effect of Pollutions on the Performance of Squirrel Cage Fan of the Kitchen Hood and Introducing the DOSG Filter

Sina Norouzi1, Mehdi Khosh Khabar Khameneh2, Ali Niknami3 , Musa Afrasiabi4

1Electrical Engineering, DORSA Company, [email protected]

2Air conditioning expert, DORSA Company 3Mechanical Engineering, DORSA Company

4Electrical Engineering, DORSA Company

ABSTRACT

ne of the major points in producing kitchen hoods is the reliability of the best performance and having high quality and safety factors. The kitchen hood parts are facing high temperature, moisture and polluted

air, which cause decreasing their lifetime and performance and make them damaged. Squirrel cage fan that consists of motor, blower and spiral gear, is the weakest part of a kitchen hood versus the mentioned damage parameters. Therefore, the optimized designing according to the electromagnetic modeling of the hood motor and its loading, performance qualification experiments for inspecting the effect of moisture and oily gases, makes the facility for performance development and increasing the qualification and lifetime of the hood. In this study, first the destructive effects of the moisture and oily gases on the motor and blower, necessity of the ventilation and weakness of the recent kitchen hoods were studied. The other problem that was investigated in this paper was the problem of secondary blowers and monitoring the condition of spiral gear. The mentioned items cause technical and economical problems, which make the clients un-satisfied. Therefore, in this paper an innovative design was recommended to solve the mentioned problem. In this idea, a special filter, which has new design, was placed in the Squirrel cage fan. This filter prevents any noise and resistance in vacuum power of the fan. In order to proof the paper claims, some experiments were designed to study the mentioned filter and its effect on the destructive parameters and increasing the performance. Therefore, the heat performance test, voltage capacity test, and balance test were done on the kitchen hood. In order to see the destructive effects of the pollutions like oily gases on the hood performance, some samples of the kitchen hood were selected to be faced the pollutions in a certain time. All the mentioned tests were done on these samples after a definite time of making the samples contaminated by the pollutions. Samples were two kinds, i.e., samples with the designed filter and sample, which has no filter. The results of this paper showed that the filter has low cost and is appropriate for home usages. It prevents damage of the hood and causes increasing of efficiency, lifetime and optimized performance of the hood. Keywords: Squirrel cage fan, vacuum power, oily gas, DOSG filter

Industrial/Professional Applications Results of the article can be applied for increasing the performance of the kitchen hoods. The new design of a special filter for kitchen hoods, decrease the cost of energy. The claim of this paper is a low cost solution to make the clients satisfied about the hood lifetime and its efficiency and consumption rate.

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Software Preparation of Mechanical Design of Fire Tube Boilers

Asghar Daneshvar Pashaki1, Mohammad Mirmosavi2, Mehran Khalili3

1Bsc. Of mechanical engineering, Machine Sazi Arak.; [email protected] 2Msc. Of mechanical engineering, Machine Sazi Arak.; [email protected]

3Bsc. Of mechanical engineering, Machine Sazi Arak.; [email protected]

ABSTRACT

echanical manual design of fire tube steam boilers require to take so much time and energy, and this matter result in high design price, delay in project and also many mistakes and errors related

to using some drawing software like AUTOCAD. For mechanical design of these boilers, like all pressure vessels different parts like shell, saddles, nozzles and the other parts should be analyzed, but the most important parts taking so much time are tube plates, which first should fix the arrangement of tubes and stay bars (with considering breathing spaces according to the standard [1]) according to tube plate thickness, design pressure and stay allowable stress. So difficulties and related defects of boiler mechanical design made us so much interested to solve this industrial problem of fired tube boilers. In this soft ware after specifying place of shell, furnace, access tube, normal water level and diameter and thickness of tubes and stays at tube plates (front, rear and wrapper) arrangement of second and third tube passes will be drawn automatically. Then by specifying the place of stays area covered by each stay will be drawn and measured automatically (the most difficult part) which because of doing so much fast (by software), designer have enough time to turn back, if there is any problem, and change the arrangement and run the program repeatedly and reach to the best arrangement at a little time. By hand one try may take some week time but by program many time can try at only some minutes. This program is written at VLISP, DCL and the other benefits of it is fast meshing of tubes, fast derive of area covered by stays , stress derivation and comparing by allowable , reading data from and writing it into another file also, user friendly, shop drawing output in “dwg.” format. Keywords: Fire tube, Software, Mechanical, Nesting, Tube plate Industrial/Professional Applications Extremely reduce design time of boiler. Reduce human error. Preparation of final drawing for construction in AutoCAD. Speed of design by this software is so that you can change your tube arrangement many times and find the best design.

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Increasing Outlet Temperature of Radiation Super Heater at Wet Back Fired Tube Boilers

Mirmoosavi Mohammad1, Daneshvar P. Asghar2, Khalili Mehran3

1Ms. Of mechanical engineering, Machine Sazi Arak; [email protected]

2Bc. Of mechanical engineering, Machine Sazi Arak; [email protected] 3Bc. Of mechanical engineering, Machine Sazi Arak; [email protected]

ABSTRACT

n this paper in order to increase temperature of super heated vapor in wet back fired tube boilers a method is introduced based on dry back fired tube boilers. Because of placing super heater at the

reversal chamber, temperature of saturated steam can be increased from 60 to 100 °C (depending on size of boiler and reversal chamber), with so much saving in material. In convection type super heaters it is difficult and so much expensive to reach this temperature and sometimes not accessible. The method introduces hear as said previously is derived from dry back super heaters with add in a layer of cement with a thickness of 50 to 70 mm at wrapper back tube plate which makes coefficient of radiation double. Keywords: unburned cement, fired tube, super heater, wet back, radiation

Industrial/Professional Applications The new mentioned design can reduces maintenance related to tube changing; refractory destruction of super heater. Construction is so easy in comparison with other types like dry back boilers. Material used will reduce so much in comparison with convective super heater.

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the 4rd international conference on heating, ventilating

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