energy efficiency assessment of a newly ......50. međunarodni kongres i izložba o kgh, beograd,...

ENERGY EFFICIENCY ASSESSMENT OF A NEWLY BUILT HOSPITAL BUILDING IN ROMANIA

Ioan Silviu DOBOȘI, DOSETIMPEX SRL, Romania

Cristina TĂNASĂ, Daro Proiect SRL, Politehnica University Timisoara, Romania

Silviana BRATA, Politehnica University Timisoara, Romania

Nicoleta KABA, Romanian Association of Building Services Engineers (AIIR), Romania

50. Međunarodni kongres i izložba o KGH, Beograd, 4–6.12.201950th International HVAC&R Congress and Exhibition, Belgrade, 4–6 Dec. 2019

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INTRODUCTION

▪ Energy consumption from fossil fuels has become a significant problem of today's society. TheEuropean Union (EU) has made ongoing attempts over the previous decade to combat thephenomenon of climate change by setting clear objectives for reducing and controlling pollutionconcentrations.

▪ The long-term goals of the EU are aimed at reducing greenhouse gas emissions up to 80- 95%by 2050. The building industry can make a major contribution on reducing greenhouse gasemissions from fossil fuels as it accounts for about 40 % of total energy consumption.

▪ To this end, the European Union (EU) has launched the 2010/31/EU Energy Performance ofBuildings Directive (EPBD), lately modified by Directive 2018/844/EU as a result of the EU'sambitious long-term strategy.

▪ The new directive emphasizes that improving the energy efficiency of buildings would contributepositively to the EU's energy independence.


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INTRODUCTION

▪ Hospital buildings are a unique category of constructions they have very rigorous design criteriafrom various angles such as structural, architectural, HVAC and quality of the indoorenvironment.

▪ Therefore, addressing energy efficiency in hospitals can be a greater challenge than for othercategories of buildings.

▪ Of the total non-residential building stock in the European Union, hospitals representapproximately 7% and are responsible for 10% of the total energy use in this sector.

▪ A German institution has conducted a survey that shows that for some hospitals, theconsumption of electricity and heating energy per bed of a hospital construction is almostequal to that of two households


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INTRODUCTION

▪ An overview on the energy in the European healthcare institution shows that: 41% to 87.5 %from the total energy consumption is related to heating, 2% to 17% corresponds to cooling and15% to 40% is occupied by electricity for lighting and equipment.

▪ The interest in enhancing the energy efficiency of hospital structures has gradually risen overtime and in recent years scientists or government institutions have conducted several studiesand papers on this subject.

▪ The European Healthcare Climate Council (EHCC) - Europe’s leading coalition of hospitals andhealth systems committed to taking action to address climate change policies.

▪ Most of the hospitals in Europe are supplied with energy from non-renewable sources. Duringthe San Francisco Global Climate Action Summit, several healthcare organizations around theworld committed to 100% use of renewable energy, which implies a decrease in greenhouse gasemissions equal to the annual emissions of over two hundred thousand vehicles.


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INTRODUCTION

▪ The energy performance and efficiency of a building is related to the building envelope andsystems but also depends greatly on the user behavior and management of the buildingoperation.

▪ Hospital buildings have special requirements for ensuring a clean air, disease control andwaste management. The design values for microclimate parameters can vary from a room toanother, depending on the activity specific to each room.

▪ Literature review states that the opportunities for energy saving in hospitals operating roomsare: airflow control based on particle concentrations; variable indoor temperature with theoutdoor weather; system shut down for the night, removing humidification and increase aircirculation.

▪ This paper presents the case study of the Mioveni City Hospital, recently built in southernRomania. The study is focused on the energy modeling for hourly simulation of the wholehospital building with the purpose of assessing the energy demand of the building and also theindoor air parameters.


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CASE STUDY AND METHODSDDD

Description of the building

▪ The case study building was recentlyconstructed in southern Romania, in Miovenicity.

▪ The investor wanted to create a new hospital toaccommodate the existing sections in the oldhospital as well as new sections in order toaccommodate diverse and complex medicalservices for the benefit of the population ofMioveni City.

Situation plan of the whole investment


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Architectural features

➢ Total built area of the hospital main building – 17448.54

m2

a) Ground floor a) First floor plan a) 3D Architectural model


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Functional features

➢ Total built area of the hospital main building – 17448.54

m2Floor Functionality Useful floor area [m2]

Basement Morgue, Kitchen, Laboratory, Laundry Room 2448.63

Ground floor Emergency Unit, Investigations, Ambulatory 2020.44

1st Floor Operating Block, Sterilization, Cardiology, Intensive Care 1936.50

2nd Floor Maternity, Operating Block and Neonatology 1721.87

3rd Floor Gynecology, Pediatrics 1721.91

4th Floor Internal medicine 1719.75

5th Floor Cardiology, Surgery and Neurology 1715.93

6th Floor Pharmacy, Administrative spaces 1788.46


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Structural system and thermal insulation

➢ Reinforced concreteframes and diaphragms

➢ Reinforced concretefloors

➢ Floor above the 6th floorthis is made of metalbeams from laminatedprofiles and mortarscreed above.

➢ The building enclosure ismade of concrete andbrick masonry walls.

Building structural system

➢ Ventilated façade system with thermal insulation of 10 cm thickbasaltic mineral wool;

➢ Ground floor insulated with 10 cm extruded polystyrene;

➢ Triple-glazed windows

➢ Roof insulated with 20 cm extruded polystyrene

Thermal insulation

Exterior wall (concrete)

Exterior wall (masonry)

Ground floorRoof

terraceExterior

fenestration

Thermal transfer resistance[m2K/W]

3.33 4.41 4.57 8.22 0.80


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HVAC and renewable energy

▪ The ventilation and air-conditioning of the entire hospital is carried out with the help of 18 airhandling units (AHU), out of which 5 AHU correspond to the five operating rooms.

▪ The sizing of the AHUs was made so as to provide the number of air exchanges required in therooms that each AHU is connected. The number of air exchanges for each room was madeaccording to the destination of the room and the classification in the purity class.

▪ The air changes range from 2 air changes h-1 for offices, corridors and cabinets to 20 airchanges h-1 for surgery rooms. Due to the very strict air quality requirements for the surgeryrooms, AHU 1 to 5 are equipped with heating and reheating coil, cooling coil, steamhumidification and intermediate heat recovery system.


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HVAC and renewable energyAir handling unit Served spaces Air flow [m3/h] Heat recovery

AHU 1 – 4 4 operating rooms in 1st floor 3000 (for each AHU) yes

AHU 5 1 operating room in 2nd floor 3000 yes

AHU 6 2nd floor 17750 yes

AHU 7 3rd floor 12400 yes

AHU 8 4th floor 10800 yes



AHU 11 Ground floor 17000 yes

AHU 13 Laboratories (basement) 5100 yes

AHU 14 Laundry rooms and morgue (basement) 7500 yes

AHU 15 Kitchen (basement) 10000 yes

AHU 16 Electric panels rooms (basement) 4500 no

AHU 17 UPS (basement) 12750 no

AHU 18 1st floor – sterilization and operating block 17500 yes

AHU 19 1st floor - cardiology and intensive care 18000 yes


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HVAC and renewable energy

▪ The heating plant is composed of three steel boilers of 900 kW each (2700 kW total), out of whichone is a reserve. The heating plant is equipped with dual burners with gas (modulating) and dieselfuel (in two stages). The main fuel is methane gas, while diesel fuel is used as an alternative whenproblems with methane gas supply are encountered.

▪ The cooling is provided by 3 air-cooled chillers (2400 kW total), out of which one is a reserve.Room terminals consist in radiators, fan convectors and chilled beams.

▪ The preparation of domestic hot water (DHW) is made in semi-instantaneous regime with 3 heatexchanger of 300 kW each and 5 storage tanks of 1000 l each. The main source of thermalenergy is a circuit from the heating plant.

▪ The secondary source for DHW is the solar energy which consists in 80 solar panels of 2.3 m2each. The solar panels are installed on the roof of the building with a distance of 2.5 m betweenpanels and inclination angle of 45⁰. The building is equipped with LED lighting.


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Energy simulation tool

▪ For this paper, the Building Simulation module from Vabi Elements software was used. This modulesimulates hourly energy flows and temperatures for a whole year, providing results of the building’sperformance.

▪ The simulation is performed based on the selected building characteristics such as HVAC systems,internal heat gains (occupancy, lighting and equipment), thermal performance of the buildingenvelope and climate.

▪ Building simulation is performed for each defined room of the building and for the entire building,providing hourly temperatures and the heating and cooling energy demand for each room.The mainadvantage of the software is that the calculation parameters and input data are entered for thewhole building and are customizable for different rooms within the building.


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Building energy modelling

▪ The geometrical model of the building was slightly simplified,obtaining a total number of 181 of rooms.

▪ The simplification comes from the fact that adjacent spaces thathave the same temperature set-point and number of airchanges, similar occupancy and lighting were defined as asingle room. The building was divided into 18 zones, one foreach AHU.

▪ To have an estimation of the energy demand required by thecase study building, the simulation takes into account scheduleof occupancy and lighting. Daily occupancy profiles were set foreach room, as well as lighting power and schedules.


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▪ The average number of persons perbuilding floor area is approximately0.07 persons/m2.

▪ The schedules for occupancy wereset as a percentage of the maximumnumber of occupants in the room,depending on the type of room.

0%

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Offices/cabinets/surgery rooms Nursing rooms

Surgery rooms Hallways, corridors

Patient rooms

Room occupancy schedules


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▪ Input data for lighting was alsodefined individually for each room,depending on the lightingrequirements established in thedesign phase .

Room type Specific lighting power [W/m2]

Patient rooms 1.5

Surgery rooms 7.5

Corridors 3

Offices, cabinets 7.5

Laboratories 15

Sterilizing room 4.5

Morgue 11.25

Bathrooms 3

Kitchen 7.5

Laundry room 4.5

specific lightingpower for each typeof space


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▪ The building mechanical ventilation is alwayson and the ventilation number of air changesfor each room was determined depending onthe room destination in accordance with theRomanian standards, as presented in theprevious chapter.

▪ The building energy model accounts for airleakage of exterior building enclosure area.The number of air changes due to infiltrationrate was set to 0.15 h-1 for thermal zones incontact with outdoor air,

Room typeNumber of air changes

[h-1]

Air temperature for heating [⁰C]

Offices, cabinets, waiting rooms,

corridors2 22

Investigation and treatment rooms,

laboratories5 24

Surgery rooms 20 24Other rooms and

corridors of surgery sector

15 24

Patients rooms 3 24Laundry room, morgue,

sterilizing room7 18


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▪ The AHUs, boilers and chillers characteristics were defined using the parameters from the technicaldocuments of each equipment.

▪ The parameters for DHW energy need calculation were set to 240 users with 55 l of hot waterdemand daily. It was not possible to define the solar system in the calculation software, thereforethe DHW produced with solar energy was calculated with the help of the online solar calculatorprovided by Hoval.


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▪ The simulation was performed using climate data for Bucharest, which is the closest location toMioveni for which we had available climate data. The annual highest temperature is 35⁰C in Julyand the lowest is -15⁰C in January.

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-15

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3Tem

per

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⁰C]

Hours of the year

Hourly temperature distribution in Bucharest


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RESULTS AND DISCUSSIONSDDD

energy consumption analysis

▪ The solar collectors cover approximately39% of the total energy consumption forDHW. As we can see, the consumption forfans, pumps and control has close valuesfor all the months of the year.

▪ The heating energy consumption is thehighest in January. A very low value ofenergy consumption for heating isregistered for the summer months. Also, alow value of energy consumption isregistered for cooling during the wintermonths

Monthly energy use by usage type

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5

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15

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25

30

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Sp

ecif

ic e

ner

gy c

on

sum

pti

on

[kW

h/m

2]

Lighting FansHumidification Domestic hot water - SOLARDomestic hot water - GAS Cooling Heating


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energy consumption analysis

▪ the energy for ventilation has the largestshare (38%) of the total energyconsumption.

▪ Due to the very strict indoor air purityrequirements, the ventilation system iscontinuously functioning throughout theyear, with number of air changes varyingfrom 2 to 20 h-1.

Percentage by usage type of total energy consumption

27%

8%

5%3%13%

37%

7%Heating

Cooling

Domestic hot water - GAS

Domestic hot water - SOLAR

Humidification

Fans

Lighting

▪ The annual energy consumption of the building is divided as follows: fans and pumps 91 kWh/m2,heating 65 kWh/m2, cooling 20 kWh/m2, domestic hot water 12 kWh/m2, humidification 33kWh/m2, lighting 18 kWh/m2. It is worth mentioning that the humidification energy consumption isrelated to the surgery rooms, since only AHU 1 to 5 are equipped with steam-based electrichumidifiers.


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Indoor air parameters evaluation

▪ For the indoor air parameters evaluation, fourrooms with various temperature requirementswere selected so as to see if the heating andcooling systems manage to maintain the desiredair temperature.

▪ The two figures show the hourly temperaturevariation for the day with the highest respectivelylowest outdoor temperature (21st of July and 13th

January). In both situations, the indoortemperature is maintained at the required valuesthroughout the day.

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Outdoor Morgue Operating room

Patient rooms Cabinet

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Hours (27th July)

Outdoor Morgue Operating roomPatient rooms Cabinet


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Indoor air parameters evaluation▪ Current research and practice suggest that Indoor

Air Quality (IAQ) can be divided into fourcategories according to CO2 concentrationsabove outdoor CO2 levels.

▪ The first category corresponds to a high quality ofindoor air and the CO2 concentration should notbe 400 ppm above the outdoor air levels.

▪ The CO2 concentration in the outdoor air for asmall city like Mioveni can be considered 375ppm.

▪ As seen in the figure, the CO2 levels remain belowthe maximum admissible CO2 concentration forspaces in category I.

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Cabinet Patients room Surgery room

CO2 level for category I - 775 ppm

Hourly CO2 for various room categories (random day)


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▪ This paper presents the building energy modelling and simulation of Mioveni hospital building, recentlycon-structed in Romania.

▪ The building combines highly insulated envelope with efficient HVAC, heat recovery, efficient lightingand integrates renewable energy as a secondary source for domestic hot water. This kind of buildingis defined by complexity due to the large variety of undertaken activities and very strict indoorenvironment requirements.

▪ The energy modelling and simulation can be a challenge, especially due to the complexity of the HVACsystem and various use patterns of the building.

▪ The simulation results show that the highest energy consumption is related to the ventilation systemas the hospital has special ventilation requirements for continuously ensuring a clean air and diseasecontrol.

▪ Approximately 39% of the energy consumption for domestic hot water is covered from renewableenergy.


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▪ The hourly indoor air temperature shows that the HVAC system assures the design requirements.

▪ The CO2 concentration levels investigated for a random day of the year show that the hospitalprovides high quality of indoor air.

▪ The limitations of this study come from the fact that the results and data are only theoretical, sincefield measurements are not yet available.

▪ However, the building is currently in the commissioning phase which means that in a short while,data about the real behavior and energetic performance of the building will be available.


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Thank you for your attention!

Ph.D. Eng. Cristina-Mariana TĂNASĂ

Daro Proiect SRL

Politehnica University Timisoara

energy efficiency assessment of a newly ......50. međunarodni kongres i izložba o kgh, beograd,...

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