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Analysis of Building Energy Consumption in a Hospital in the Hot Summer and Cold Winter Area
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Energy Procedia 158 Energy Procedia 00(2019) (2017)3735–3740 000–000 www.elsevier.com/locate/procedia
10th International Conference on Applied Energy (ICAE2018), 22-25 August 2018, Hong Kong, 10th International Conference on Applied Energy China(ICAE2018), 22-25 August 2018, Hong Kong, China
Analysis of Building Energy Consumption in a Hospital The 15th International Energy SymposiumConsumption on District Heatingin and Analysis of Building a Cooling Hospital in the Hot Summer and Cold Winter Area in the Hot Summer and Cold Winter Area Assessing the feasibility of using the heat demand-outdoor Chenyao Shenaa, Kang Zhaoaa*, Jian Geaa, Qingli Zhoubb Chenyao Shen Zhao *, Jian Ge , Qingli temperature function for, Kang a long-term district heatZhou demand forecast College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China. a ab
College of Civil Engineering Architecture, Zhejiang University, Hangzhou The Fourth Affiliated Hospitaland Zhejiang University School of Medicine, Jinhua 310058, 322000, China.
a,b,c a a b c Fourth Zhejiang University School of Medicine, Jinhua 322000,,China. I. AndrićThe *, A.Affiliated PinaHospital , P. Ferrão , J. Fournier ., B. Lacarrière O. Le Correc b
a
IN+ Center for Innovation, Technology and Policy Research - Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal b
Veolia Recherche & Innovation, 291 Avenue Dreyfous Daniel, 78520 Limay, France Abstract c Département Systèmes Énergétiques et Environnement - IMT Atlantique, 4 rue Alfred Kastler, 44300 Nantes, France Abstract A hospital building features a number of different functional areas. The equipment and systems that serve the building and its A hospital building features and a number different functional areas. The equipment andgas, systems its medical needs are complex requireofvarious forms of energy, including electricity, steam,that hotserve waterthe andbuilding chilled and water. medical needs are complex anddata require of consumption energy, including electricity, gas, steam, hot water and that chilled water. Domestic and foreign research showvarious that theforms energy per unit area of hospital buildings is twice of general Abstractand foreign research data show that the energy consumption per unit area of hospital buildings is twice that of general Domestic public buildings. This article selects a typical comprehensive hospital in the hot summer and cold winter area as a case, analyzes public buildings. article a typical comprehensive hospital in thedata, hot and summer cold winter area suggestions as a case, analyzes the actual energyThis demand of selects the hospital building through the measured putsand forward reasonable on the District heating commonly addressed in thethe literature as one theputs mostforward effective solutionssuggestions for decreasing the the actual energy networks demand ofarethe hospital building through measured data,ofand reasonable on the energy consumption mode and system improvement plan of the hospital in combination with the operating conditions. greenhouse gas emissions from the building sector.plan These systems require high investments which are returned through the heat energy consumption mode and system improvement of the hospital in combination with the operating conditions. sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, Copyright © 2018 Elsevier Ltd. All rights reserved. © 2019 The Published by Elsevier Ltd. prolonging the investment return Copyright ©Authors. 2018 Elsevier Ltd. Allperiod. rights reserved. Selection and peer-review under responsibility of the scientific committee of the 10th International Conference on Applied This ismain an open access article under the CCthe BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) The scope of this paper is to assess feasibility using the heat demand – outdoor temperature Conference function for on heatApplied demand Selection and peer-review under responsibility of the of scientific committee of the 10th International Energy (ICAE2018). Peer-review under responsibility of the scientific committee of ICAE2018 The as 10th Conference forecast. The district of Alvalade, located in Lisbon (Portugal), was –used a International case study. The district on is Applied consistedEnergy. of 665 Energy (ICAE2018). buildingsHot thatsummer vary in construction periodBuilding and typology. Keywords: andboth cold winter area; Hospital; energy Three weather scenarios (low, medium, high) and three district renovation were intermediate, Keywords: Hotscenarios summer and colddeveloped winter area;(shallow, Hospital; Building energy deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications 1. Introduction error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation 1.(the Introduction scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). Hospital are energy-intensive buildings their all-weather high-cost operation, sophisticated The value ofbuildings slope coefficient increased on average withindue the to range of 3.8% up to 8% per decade, that corresponds to the Hospital buildings are energy-intensive buildings due toenvironmental their all-weather high-cost operation, sophisticated medical equipment as well as strict cleaning procedures and parameters. Compared with types decrease in the number of heating hours of 22-139h during the heating season (depending on the combination ofother weather and medical equipment as well as strict cleaning procedures environmental parameters. Compared types of buildings, hospital buildings have a other particularly large and impact onincreased the full cycle of the environment. In other the United renovation scenarios considered). On the hand, function intercept for 7.8-12.7% per decade with (depending on the ofcoupled buildings, hospital buildings have a energy-intensive particularly large impactthe on function the full parameters cycle of energy the In the States, hospitals areThe the secondsuggested largest commercial buildings, with per United square scenarios). values could be used to modify forenvironment. theconsumption scenarios considered, and States, hospitals are the second largest energy-intensive commercial buildings, with energy consumption per square improve the accuracy of heat demand estimations.
© 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. * Corresponding author. Tel.: 0571-88206396; fax: 0571-88206264. * E-mail Corresponding Tel.: 0571-88206396; fax: 0571-88206264. address:author. [email protected] Keywords: Heat demand; Forecast; Climate change E-mail address: [email protected]
1876-6102 Copyright © 2018 Elsevier Ltd. All rights reserved. 1876-6102 Copyright © 2018 Elsevier Ltd. All of rights reserved. committee of the 10th International Conference on Applied Energy (ICAE2018). Selection and peer-review under responsibility the scientific Selection and peer-review under responsibility of the scientific committee of the 10th International Conference on Applied Energy (ICAE2018). 1876-6102 © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. 1876-6102 © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of ICAE2018 – The 10th International Conference on Applied Energy. 10.1016/j.egypro.2019.01.883
Chenyao Shen et al. / Energy Procedia 158 (2019) 3735–3740 Chenyao Shen/ Energy Procedia 00 (2018) 000–000
3736 2
foot twice that of office buildings [1]. In Brazil, hospital buildings energy consumption accounts for 10.6% of total energy consumption in the country [2]. Hospital buildings have great potential for energy conservation. The energy consumption structure of hospital buildings is also more complex than that of ordinary public buildings. Its daily energy consumption is chiefly electricity, used for lighting, elevators, air conditioning and ventilation equipment. Gas or fuel oil is used as the main source of energy for steam, hot water, disinfection, washing, kitchens, etc. In addition, different types of medical equipment feature various operating requirements as well as long operating hours, and require flexible control. The energy consumption of hospital buildings presents both intermittent and continuous characteristics with the unit energy load changing vastly, resulting in a lot of waste. According to statistics, in the past five years, the average energy expenditure of hospital buildings in China has increased by 53.4%, accounting for more than 10% of the total operating costs of hospitals [3]. Energy-saving in hospital buildings is imminent. In summer and winter cold areas, buildings need to be cooled and dehumidified in summer and provided heat in winter. Based on the analysis of measured data, this paper discusses the energy consumption mode and energy-saving approach of a hospital building in the hot summer and cold winter area. 2. Construction and System Information 2.1. Construction information The comprehensive hospital is located in the hot summer and cold winter area of Zhejiang, China and was put into operation in October 2014. The total construction area of the hospital is 110,000 ㎡, among which outpatient service (including the emergency room) and operation area is 64,300 ㎡, hospitalization area 29,300 ㎡ (the area for designed beds is 920 ㎡), logistics area (including the cafeteria, laundry rooms and equipment rooms) is 4,700 ㎡, and the area of apartments for the use of doctors and nurses 11,700 ㎡. At present, the actual used area accounts for 70% of the total area, of which the area of wards in use makes up half of the total area of wards. The outpatient amount is 1,200 people per day. 2.2. Energy for construction and medical use With reference to ISO 12655 standard [4], the energy required for the construction of hospital buildings and medical equipment is summarized in Figure 1.
Processing conversion
Electricity
10kV
Distribution delivery
Transformer
Natural gas
Steam boiler
HVAC
380V
Domestic hot water Lighting and plug-in
Solar water heater Hot water boiler
Terminal use
Elevators
Hot water
Building auxiliary devices
Steam
Devices in data center
Natural gas
Cooking Laundry Medical equipment
Fig.1. Energy use of the building at each stage
Chenyao Shen et al. / Energy Procedia 158 (2019) 3735–3740 Author name / Energy Procedia 00 (2018) 000–000
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The main energy sources for the hospital are electricity and natural gas. Its daily energy consumption is mainly electric power. The power feeding is realized via three 10kV high-voltage cables and the power distributions uses 8 transformers with a diesel generator set for equipment use. Electrical energy is mainly used for heating, air conditioning, ventilation, elevators, lighting, in-patient departments, kitchens, logistics, and special power supply in medical buildings. The hospital also uses natural gas as its main energy source. Some of it directly burns to supply the energy for the open flame, steam, and hot-water in the kitchen; some goes to hospital boiler systems, including hot-water boilers and steam boilers. Hot-water boilers usually produce domestic hot water (for patient departments, kitchens, logistics, and laundry rooms), which in winter also supplies for heating. Steam boilers mainly provide steam in the laundry room, operating room and supply room. 2.3. The main energy consumption system The main energy consumption system of the hospital comprises the central air conditioning system, clean air conditioning system, ventilation system, lighting system, domestic hot water system, steam system, water supply and drainage system and kitchen system. 1) The heating and air conditioning system The outpatient, surgical and inpatient areas employ water-circulated central air-conditioning, whose designed cooling load for summer is 9,303 kW and designed heating load for winter 5,582 kW. The cold source is provided by a set of three 750-standard ton centrifugal units and a set of one 360-standard ton screw conveyor, with a rated COP of 5.8. The heat source is provided by a set of three 2,791 kW vacuum hot-water boilers. For the operating room area, an air-cooled heat pump unit is installed at the top of the podium as a cleanroom air-conditioner facilitating the cold and heating sources. In local areas (such as the cafeteria), heat exchangers are installed to recover heat from exhaust air. The air conditioners at the exits of the outpatient department and ward area employs independently turnable fan coils, clean rooms such as the operating room adopts cleanroom air conditioners, and the local areas such as the emergency room use interconnected air-conditioning units. In other non-essential areas such as logistics complexes, duty quarters, control centers, elevator rooms, etc., interconnected or split air conditioning units are separately installed. 2) The domestic hot water system Domestic hot water in the hospital comprises water used in the cafeteria and bathing water. A part of the heat source comes from solar hot water, and part of it comes from the hot water boiler shared with the heating system. The area of solar collector plates is approximately 750㎡, which is designed to provide 39.3 tons of hot water per day, accounting for 13.3% of domestic hot water consumption. 3) The energy consumption for lighting and sockets The fluorescent lamps are used in consulting rooms, wards and garages, and energy-saving fluorescent lamps are used in public areas such as entrance halls, walkways, and elevator halls. According to the needs of use and natural lighting conditions, the artificial lighting adopts section control. However, due to the complex structure of the functional areas of the hospital, the schedules are not unified, and the artificial lighting is currently controlled by the personnel in each region. 4) The steam system The operating room, supply room and laundry room of the hospital need steam for disinfection, heating and humidification, etc. Therefore, a steam system has been set up to provide steam from two gas-fired steam boilers with an evaporation capacity of 1.5 tons per hour. 5) The cafeteria energy consumption system The open flames, steam and hot water energy used in hospital kitchens are all supplied by burning natural gas. The chief equipment such as electric and steam rice cookers, electric and steam steamers, and electric and steam heating sandwich pots are all independent and can be heated via electricity directly. 3. Building Energy Consumption Analysis 3.1. Comprehensive energy consumption analysis 3.1.1 Annual Energy Consumption Statistics
Chenyao Shen et al. / Energy Procedia 158 (2019) 3735–3740 Chenyao Shen/ Energy Procedia 00 (2018) 000–000
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From April 2015 to March 2016, the hospital used a total of 8,156 MWh of electricity, 582,154 m³ of natural gas, and the annual total energy consumption adds up to 9.06 million yuan [5]. Considering the utilization rate, the actual use area is calculated as 70% of the total construction area, that is, the hospital's energy consumption area is 77,000 ㎡. The annual unit area energy consumption index is thus shown in Table 1. It will be of convenience to convert each type of energy consumption into standard coal in the analysis. [6] Table 1. Annual energy consumption index of the hospital per unit area Items
Annual energy consumption
Annual consumption per unit area
Standard coal consumption
Ratio of energy consumption
Ratio of energy consumption cost
(2015.4 ~2016.3)
(Energy consumption area of 77,000 ㎡)
Electricity
8156140 kWh
105.9 kWh/m²
33.9
66%
76%
Natural gas
582154 m³
7.6 m³/m²
10.1
34%
24%
44.0
-
-
Total
(kgce/m²)
* Among them, the conversion coefficient of standard coal consumption for electricity and for natural gas is 0.320 kgce/kWh and 1.330 kgce/m³, respectively.
According to the 12th Five-Year Survey of National Hundred Hospitals [8], the median annual power consumption per unit area in the hot summer and cold winter areas is 104.8 kWh/(㎡∙a), which is higher than the national median power consumption of 96.1 kWh/( ㎡ ∙a). At the same time, with reference to the energy consumption survey data of 30 general hospitals in Zhejiang Province [9], the comprehensive energy consumption per unit building area of tertiary hospitals is in the range of 28.28 to 150.14 kgce/kWh per year, with an average of 63.36 kgce/kWh. It can be seen that the energy consumption per unit area of the hospital in question is lower than the average level and is more energy-efficient than that of a hospital of the same climate zone (in the hot summer and cold winter area) and also that of a hospital of the same scale (a tertiary general hospital). However, consideration should also be given to operational conditions (high-energy-consuming departments such as obstetrics, neonatology, and emergency ICU have not yet been established, and the infected building has not been activated). 3.2. Energy Analysis by Item The hospital's major energy consumption is concentrated in the outpatient, surgical and inpatient areas. Therefore, during analysis, the energy consumption of the auxiliary logistics area and apartments is deducted from the total (the annual energy consumption of the hospital's logistics area is 436563 kWh, on duty; the annual energy consumption of the apartments is 457182 kWh).
Fig. 2-a. Energy breakdown structure diagram
Chenyao Shen/ Energy et al. / Energy Procedia 158000–000 (2019) 3735–3740 Author name Procedia 00 (2018)
Fig. 2-b. Energy structure diagram with the electricity breakdown
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Fig. 2-c. Energy structure diagram with the natural gas breakdown
According to Fig. 2-a, it can be seen that the energy consumption of the medical building's comfortable air conditioning (31%) and the cleanroom air-conditioning (9%) accounts for 40% of the total annual energy consumption. The boiler system (12% for steam boilers and 7% for hot-water boilers) can consume nearly one-fifth of energy, and the lighting energy consumption also accounts for 15%. Therefore, the air-conditioning, boilers, and lighting systems in medical buildings are the main directions for energy-saving transformation in hospitals. According to the statistics of electricity consumption of the hospital, the breakdown comprises subitems such as electricity for air-conditioning systems, lighting outlets, power systems, medical equipment, logistics areas, elevators, power and other electricity uses. According to Fig. 2-b, the electricity consumption of the air-conditioning system accounts for about 34% of the total power consumption; the lighting system and outlets account for about 21% of the total power consumption; and the power system accounts for 13% of the total power consumption; other systems account for 32% of total power consumption. Air conditioning and lighting power consumption makes up more than half. The boilers of the hospital are mainly divided into hot water boilers and steam boilers. Hot water boilers usually produce hot water for domestic use, and in the winter, they also supply hot water for heating. Steam boilers mainly supply steam in laundry rooms, operating rooms, and supply rooms. Both hot water boilers and steam boilers use natural gas as a fuel. In addition, the cafeteria is also the main user of natural gas. When the amount of natural gas consumption is calculated based on the division of subitems of domestic water, heating for winter and kitchens, the proportion of the main movement distribution of natural gas in the hospital is obtained. According to Figure 2-c, the gas consumption of the hospitals for the heating system in winter accounts for about 45% of the total gas consumption; the gas consumption of domestic hot water accounts for 17%; and that of steam boilers accounts for 31%. The management of energy-saving operation of hot-water boilers and steam boilers will be the priority. 4. Energy Saving Suggestions According to the analysis of energy consumption data, air conditioning, boilers, and lighting systems in medical buildings are the main directions for energy-saving transformation in hospitals. This section proposes feasible energy-saving suggestions for these three key energy-saving items. 1) Air conditioning system The fresh air volume of the central air-conditioning system is constant, and it is not possible to adjust the fresh air volume according to the actual flow of people. It is recommended to adjust the amount of air supply according to the indoor CO2 level so as to save energy consumption for fresh air treatment. There is no distinction between 24-hour operation and operating time-only operation in the air-conditioning hot and cold water transmission and distribution system. Therefore, the hot and cold water in the main pipe requires 24 hours of continuous circulation, resulting in the waste of water pump energy. It is recommended that reasonable divisions should be made according to usage conditions, such as outpatient service, office work, etc., which only operate during working hours. 2) Boiler equipment
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Chenyao Shen et al. / Energy Procedia 158 (2019) 3735–3740 Chenyao Shen/ Energy Procedia 00 (2018) 000–000
There is a need for domestic hot water all year round in the hospital's cafeteria and bathing room, but the capacity is only about 20% of a single boiler. In the non-heating season, the boiler operates at a low load rate and is thus less efficient. It is recommended to set up a air source heat pump unit that serves domestic hot water according to actual needs so as to improve energy supply efficiency. 3) Lighting system At present, the lighting of the medical building is mainly controlled by the personnel in each functional area, and the lighting control circuit in the public area is integrated. It can not be adjusted according to the needs of the subregions. It is recommended to use multiple channels to independently control the lighting in each public area, to rearrange the lighting in the well-lighted area, and to use the light sensor to automatically control the daylight switches to achieve energy savings. In addition, it is found that the garage lighting is always on for 24 hours even if in the period in which no car enters the garage. Besides, in the open area, the lights are turned on during the day, resulting in the waste of energy. It is recommended to use microwave induction system. Light sensing system is applied to the outdoor lighting of the garage, and the lighting is automatically powered off in the daytime. 5. Summary Energy-saving in hospital buildings is imminent. This article selects a typical comprehensive hospital in the hot summer and cold winter area as a case, analyzes the actual energy demand of the hospital building through the measured data, and puts forward reasonable suggestions on the energy consumption mode and the system improvement plan of the hospital based on the operating conditions. Compared with the climate zone (the hot summer and cold winter areas) and hospitals of the same scale (tertiary general hospitals), the hospital's energy consumption per unit area is lower than average. Its daily energy consumption is dominated by electricity, which accounts for 66% of energy consumption and is used in lighting, elevators, air conditioning and ventilation equipment; followed by gas (oil), etc. as the main energy source for steam, hot water, disinfection and washing, kitchens, etc. Among them, the medical building comfortable air-conditioning and cleanroom air-conditioning energy consumption account for more than one-third of the annual total energy consumption; the boiler system uses close to nearly one-fifth of the energy, lighting energy consumption also accounts for more than 14%. Therefore, air-conditioning, boilers, and lighting systems are the main directions for energy efficiency in hospital buildings. Combined with the actual operation situation, this article discusses feasible energy-saving suggestions. Acknowledgements The authors appreciate the support from the China National Key R&D Program (No. 2016YFC0700100) and the Zhejiang Provincial Natural Science Foundation of China (No. LQ17E080009). References [1] Barb Kaiser, Patrick D. Eagan, Hollie Shaner. Solutions to Health Care Waste: Life-Cycle Thinking and "Green" Purchasing[J]. Environmental Health Perspectives, 2001, 109(3):205. [2] Pinzone M, Lettieri E, Masella C. Proactive Environmental Strategies in Healthcare Organisations: Drivers and Barriers in Italy[J]. Journal of Business Ethics, 2015, 131(1):1-15. [3] Shen Jinming, Yan Mingming, Lu Wen. The Characteristics of Hospital Energy Consumption and the Disadvantages of Traditional Cold and Heat Sources[J]. Chinese Hospital Architecture and Equipment, 2008, 9(11):8-13. [4] ISO 12655:2013 Energy Performance of Buildings - Presentation of measured energy use of buildings [5] Energy Diagnosis Report of the Fourth Affiliated Hospital, Zhejiang University School of Medicine [6] "General Principles for Comprehensive Energy Consumption Calculation" (GB/T2589-2008) [7] Jiang Yi, Yang Xiu. Equivalent Power Method in Energy Analysis[J]. Energy of China, 2010, 32(5):5-11. [8] Zhao Wei, Di Yanqiang. Technical Guide for Green Transformation of Hospital Buildings[M]. China Building Industry Press, 2015. [9] Lu Wei, Chang Yanxin. Investigation on Energy Consumption and Its Influencing Factors of Hospital Buildings in Zhejiang Province[J]. Building Science, 2010, 26(4):48-51.
ScienceDirect ScienceDirect
Energyonline Procedia 00 (2018) 000–000 Available onlineatat www.sciencedirect.com Available www.sciencedirect.com Energy Procedia 00 (2018) 000–000
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www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia
Energy Procedia 158 Energy Procedia 00(2019) (2017)3735–3740 000–000 www.elsevier.com/locate/procedia
10th International Conference on Applied Energy (ICAE2018), 22-25 August 2018, Hong Kong, 10th International Conference on Applied Energy China(ICAE2018), 22-25 August 2018, Hong Kong, China
Analysis of Building Energy Consumption in a Hospital The 15th International Energy SymposiumConsumption on District Heatingin and Analysis of Building a Cooling Hospital in the Hot Summer and Cold Winter Area in the Hot Summer and Cold Winter Area Assessing the feasibility of using the heat demand-outdoor Chenyao Shenaa, Kang Zhaoaa*, Jian Geaa, Qingli Zhoubb Chenyao Shen Zhao *, Jian Ge , Qingli temperature function for, Kang a long-term district heatZhou demand forecast College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China. a ab
College of Civil Engineering Architecture, Zhejiang University, Hangzhou The Fourth Affiliated Hospitaland Zhejiang University School of Medicine, Jinhua 310058, 322000, China.
a,b,c a a b c Fourth Zhejiang University School of Medicine, Jinhua 322000,,China. I. AndrićThe *, A.Affiliated PinaHospital , P. Ferrão , J. Fournier ., B. Lacarrière O. Le Correc b
a
IN+ Center for Innovation, Technology and Policy Research - Instituto Superior Técnico, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal b
Veolia Recherche & Innovation, 291 Avenue Dreyfous Daniel, 78520 Limay, France Abstract c Département Systèmes Énergétiques et Environnement - IMT Atlantique, 4 rue Alfred Kastler, 44300 Nantes, France Abstract A hospital building features a number of different functional areas. The equipment and systems that serve the building and its A hospital building features and a number different functional areas. The equipment andgas, systems its medical needs are complex requireofvarious forms of energy, including electricity, steam,that hotserve waterthe andbuilding chilled and water. medical needs are complex anddata require of consumption energy, including electricity, gas, steam, hot water and that chilled water. Domestic and foreign research showvarious that theforms energy per unit area of hospital buildings is twice of general Abstractand foreign research data show that the energy consumption per unit area of hospital buildings is twice that of general Domestic public buildings. This article selects a typical comprehensive hospital in the hot summer and cold winter area as a case, analyzes public buildings. article a typical comprehensive hospital in thedata, hot and summer cold winter area suggestions as a case, analyzes the actual energyThis demand of selects the hospital building through the measured putsand forward reasonable on the District heating commonly addressed in thethe literature as one theputs mostforward effective solutionssuggestions for decreasing the the actual energy networks demand ofarethe hospital building through measured data,ofand reasonable on the energy consumption mode and system improvement plan of the hospital in combination with the operating conditions. greenhouse gas emissions from the building sector.plan These systems require high investments which are returned through the heat energy consumption mode and system improvement of the hospital in combination with the operating conditions. sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, Copyright © 2018 Elsevier Ltd. All rights reserved. © 2019 The Published by Elsevier Ltd. prolonging the investment return Copyright ©Authors. 2018 Elsevier Ltd. Allperiod. rights reserved. Selection and peer-review under responsibility of the scientific committee of the 10th International Conference on Applied This ismain an open access article under the CCthe BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) The scope of this paper is to assess feasibility using the heat demand – outdoor temperature Conference function for on heatApplied demand Selection and peer-review under responsibility of the of scientific committee of the 10th International Energy (ICAE2018). Peer-review under responsibility of the scientific committee of ICAE2018 The as 10th Conference forecast. The district of Alvalade, located in Lisbon (Portugal), was –used a International case study. The district on is Applied consistedEnergy. of 665 Energy (ICAE2018). buildingsHot thatsummer vary in construction periodBuilding and typology. Keywords: andboth cold winter area; Hospital; energy Three weather scenarios (low, medium, high) and three district renovation were intermediate, Keywords: Hotscenarios summer and colddeveloped winter area;(shallow, Hospital; Building energy deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications 1. Introduction error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation 1.(the Introduction scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). Hospital are energy-intensive buildings their all-weather high-cost operation, sophisticated The value ofbuildings slope coefficient increased on average withindue the to range of 3.8% up to 8% per decade, that corresponds to the Hospital buildings are energy-intensive buildings due toenvironmental their all-weather high-cost operation, sophisticated medical equipment as well as strict cleaning procedures and parameters. Compared with types decrease in the number of heating hours of 22-139h during the heating season (depending on the combination ofother weather and medical equipment as well as strict cleaning procedures environmental parameters. Compared types of buildings, hospital buildings have a other particularly large and impact onincreased the full cycle of the environment. In other the United renovation scenarios considered). On the hand, function intercept for 7.8-12.7% per decade with (depending on the ofcoupled buildings, hospital buildings have a energy-intensive particularly large impactthe on function the full parameters cycle of energy the In the States, hospitals areThe the secondsuggested largest commercial buildings, with per United square scenarios). values could be used to modify forenvironment. theconsumption scenarios considered, and States, hospitals are the second largest energy-intensive commercial buildings, with energy consumption per square improve the accuracy of heat demand estimations.
© 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. * Corresponding author. Tel.: 0571-88206396; fax: 0571-88206264. * E-mail Corresponding Tel.: 0571-88206396; fax: 0571-88206264. address:author. [email protected] Keywords: Heat demand; Forecast; Climate change E-mail address: [email protected]
1876-6102 Copyright © 2018 Elsevier Ltd. All rights reserved. 1876-6102 Copyright © 2018 Elsevier Ltd. All of rights reserved. committee of the 10th International Conference on Applied Energy (ICAE2018). Selection and peer-review under responsibility the scientific Selection and peer-review under responsibility of the scientific committee of the 10th International Conference on Applied Energy (ICAE2018). 1876-6102 © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. 1876-6102 © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of ICAE2018 – The 10th International Conference on Applied Energy. 10.1016/j.egypro.2019.01.883
Chenyao Shen et al. / Energy Procedia 158 (2019) 3735–3740 Chenyao Shen/ Energy Procedia 00 (2018) 000–000
3736 2
foot twice that of office buildings [1]. In Brazil, hospital buildings energy consumption accounts for 10.6% of total energy consumption in the country [2]. Hospital buildings have great potential for energy conservation. The energy consumption structure of hospital buildings is also more complex than that of ordinary public buildings. Its daily energy consumption is chiefly electricity, used for lighting, elevators, air conditioning and ventilation equipment. Gas or fuel oil is used as the main source of energy for steam, hot water, disinfection, washing, kitchens, etc. In addition, different types of medical equipment feature various operating requirements as well as long operating hours, and require flexible control. The energy consumption of hospital buildings presents both intermittent and continuous characteristics with the unit energy load changing vastly, resulting in a lot of waste. According to statistics, in the past five years, the average energy expenditure of hospital buildings in China has increased by 53.4%, accounting for more than 10% of the total operating costs of hospitals [3]. Energy-saving in hospital buildings is imminent. In summer and winter cold areas, buildings need to be cooled and dehumidified in summer and provided heat in winter. Based on the analysis of measured data, this paper discusses the energy consumption mode and energy-saving approach of a hospital building in the hot summer and cold winter area. 2. Construction and System Information 2.1. Construction information The comprehensive hospital is located in the hot summer and cold winter area of Zhejiang, China and was put into operation in October 2014. The total construction area of the hospital is 110,000 ㎡, among which outpatient service (including the emergency room) and operation area is 64,300 ㎡, hospitalization area 29,300 ㎡ (the area for designed beds is 920 ㎡), logistics area (including the cafeteria, laundry rooms and equipment rooms) is 4,700 ㎡, and the area of apartments for the use of doctors and nurses 11,700 ㎡. At present, the actual used area accounts for 70% of the total area, of which the area of wards in use makes up half of the total area of wards. The outpatient amount is 1,200 people per day. 2.2. Energy for construction and medical use With reference to ISO 12655 standard [4], the energy required for the construction of hospital buildings and medical equipment is summarized in Figure 1.
Processing conversion
Electricity
10kV
Distribution delivery
Transformer
Natural gas
Steam boiler
HVAC
380V
Domestic hot water Lighting and plug-in
Solar water heater Hot water boiler
Terminal use
Elevators
Hot water
Building auxiliary devices
Steam
Devices in data center
Natural gas
Cooking Laundry Medical equipment
Fig.1. Energy use of the building at each stage
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The main energy sources for the hospital are electricity and natural gas. Its daily energy consumption is mainly electric power. The power feeding is realized via three 10kV high-voltage cables and the power distributions uses 8 transformers with a diesel generator set for equipment use. Electrical energy is mainly used for heating, air conditioning, ventilation, elevators, lighting, in-patient departments, kitchens, logistics, and special power supply in medical buildings. The hospital also uses natural gas as its main energy source. Some of it directly burns to supply the energy for the open flame, steam, and hot-water in the kitchen; some goes to hospital boiler systems, including hot-water boilers and steam boilers. Hot-water boilers usually produce domestic hot water (for patient departments, kitchens, logistics, and laundry rooms), which in winter also supplies for heating. Steam boilers mainly provide steam in the laundry room, operating room and supply room. 2.3. The main energy consumption system The main energy consumption system of the hospital comprises the central air conditioning system, clean air conditioning system, ventilation system, lighting system, domestic hot water system, steam system, water supply and drainage system and kitchen system. 1) The heating and air conditioning system The outpatient, surgical and inpatient areas employ water-circulated central air-conditioning, whose designed cooling load for summer is 9,303 kW and designed heating load for winter 5,582 kW. The cold source is provided by a set of three 750-standard ton centrifugal units and a set of one 360-standard ton screw conveyor, with a rated COP of 5.8. The heat source is provided by a set of three 2,791 kW vacuum hot-water boilers. For the operating room area, an air-cooled heat pump unit is installed at the top of the podium as a cleanroom air-conditioner facilitating the cold and heating sources. In local areas (such as the cafeteria), heat exchangers are installed to recover heat from exhaust air. The air conditioners at the exits of the outpatient department and ward area employs independently turnable fan coils, clean rooms such as the operating room adopts cleanroom air conditioners, and the local areas such as the emergency room use interconnected air-conditioning units. In other non-essential areas such as logistics complexes, duty quarters, control centers, elevator rooms, etc., interconnected or split air conditioning units are separately installed. 2) The domestic hot water system Domestic hot water in the hospital comprises water used in the cafeteria and bathing water. A part of the heat source comes from solar hot water, and part of it comes from the hot water boiler shared with the heating system. The area of solar collector plates is approximately 750㎡, which is designed to provide 39.3 tons of hot water per day, accounting for 13.3% of domestic hot water consumption. 3) The energy consumption for lighting and sockets The fluorescent lamps are used in consulting rooms, wards and garages, and energy-saving fluorescent lamps are used in public areas such as entrance halls, walkways, and elevator halls. According to the needs of use and natural lighting conditions, the artificial lighting adopts section control. However, due to the complex structure of the functional areas of the hospital, the schedules are not unified, and the artificial lighting is currently controlled by the personnel in each region. 4) The steam system The operating room, supply room and laundry room of the hospital need steam for disinfection, heating and humidification, etc. Therefore, a steam system has been set up to provide steam from two gas-fired steam boilers with an evaporation capacity of 1.5 tons per hour. 5) The cafeteria energy consumption system The open flames, steam and hot water energy used in hospital kitchens are all supplied by burning natural gas. The chief equipment such as electric and steam rice cookers, electric and steam steamers, and electric and steam heating sandwich pots are all independent and can be heated via electricity directly. 3. Building Energy Consumption Analysis 3.1. Comprehensive energy consumption analysis 3.1.1 Annual Energy Consumption Statistics
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From April 2015 to March 2016, the hospital used a total of 8,156 MWh of electricity, 582,154 m³ of natural gas, and the annual total energy consumption adds up to 9.06 million yuan [5]. Considering the utilization rate, the actual use area is calculated as 70% of the total construction area, that is, the hospital's energy consumption area is 77,000 ㎡. The annual unit area energy consumption index is thus shown in Table 1. It will be of convenience to convert each type of energy consumption into standard coal in the analysis. [6] Table 1. Annual energy consumption index of the hospital per unit area Items
Annual energy consumption
Annual consumption per unit area
Standard coal consumption
Ratio of energy consumption
Ratio of energy consumption cost
(2015.4 ~2016.3)
(Energy consumption area of 77,000 ㎡)
Electricity
8156140 kWh
105.9 kWh/m²
33.9
66%
76%
Natural gas
582154 m³
7.6 m³/m²
10.1
34%
24%
44.0
-
-
Total
(kgce/m²)
* Among them, the conversion coefficient of standard coal consumption for electricity and for natural gas is 0.320 kgce/kWh and 1.330 kgce/m³, respectively.
According to the 12th Five-Year Survey of National Hundred Hospitals [8], the median annual power consumption per unit area in the hot summer and cold winter areas is 104.8 kWh/(㎡∙a), which is higher than the national median power consumption of 96.1 kWh/( ㎡ ∙a). At the same time, with reference to the energy consumption survey data of 30 general hospitals in Zhejiang Province [9], the comprehensive energy consumption per unit building area of tertiary hospitals is in the range of 28.28 to 150.14 kgce/kWh per year, with an average of 63.36 kgce/kWh. It can be seen that the energy consumption per unit area of the hospital in question is lower than the average level and is more energy-efficient than that of a hospital of the same climate zone (in the hot summer and cold winter area) and also that of a hospital of the same scale (a tertiary general hospital). However, consideration should also be given to operational conditions (high-energy-consuming departments such as obstetrics, neonatology, and emergency ICU have not yet been established, and the infected building has not been activated). 3.2. Energy Analysis by Item The hospital's major energy consumption is concentrated in the outpatient, surgical and inpatient areas. Therefore, during analysis, the energy consumption of the auxiliary logistics area and apartments is deducted from the total (the annual energy consumption of the hospital's logistics area is 436563 kWh, on duty; the annual energy consumption of the apartments is 457182 kWh).
Fig. 2-a. Energy breakdown structure diagram
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Fig. 2-b. Energy structure diagram with the electricity breakdown
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Fig. 2-c. Energy structure diagram with the natural gas breakdown
According to Fig. 2-a, it can be seen that the energy consumption of the medical building's comfortable air conditioning (31%) and the cleanroom air-conditioning (9%) accounts for 40% of the total annual energy consumption. The boiler system (12% for steam boilers and 7% for hot-water boilers) can consume nearly one-fifth of energy, and the lighting energy consumption also accounts for 15%. Therefore, the air-conditioning, boilers, and lighting systems in medical buildings are the main directions for energy-saving transformation in hospitals. According to the statistics of electricity consumption of the hospital, the breakdown comprises subitems such as electricity for air-conditioning systems, lighting outlets, power systems, medical equipment, logistics areas, elevators, power and other electricity uses. According to Fig. 2-b, the electricity consumption of the air-conditioning system accounts for about 34% of the total power consumption; the lighting system and outlets account for about 21% of the total power consumption; and the power system accounts for 13% of the total power consumption; other systems account for 32% of total power consumption. Air conditioning and lighting power consumption makes up more than half. The boilers of the hospital are mainly divided into hot water boilers and steam boilers. Hot water boilers usually produce hot water for domestic use, and in the winter, they also supply hot water for heating. Steam boilers mainly supply steam in laundry rooms, operating rooms, and supply rooms. Both hot water boilers and steam boilers use natural gas as a fuel. In addition, the cafeteria is also the main user of natural gas. When the amount of natural gas consumption is calculated based on the division of subitems of domestic water, heating for winter and kitchens, the proportion of the main movement distribution of natural gas in the hospital is obtained. According to Figure 2-c, the gas consumption of the hospitals for the heating system in winter accounts for about 45% of the total gas consumption; the gas consumption of domestic hot water accounts for 17%; and that of steam boilers accounts for 31%. The management of energy-saving operation of hot-water boilers and steam boilers will be the priority. 4. Energy Saving Suggestions According to the analysis of energy consumption data, air conditioning, boilers, and lighting systems in medical buildings are the main directions for energy-saving transformation in hospitals. This section proposes feasible energy-saving suggestions for these three key energy-saving items. 1) Air conditioning system The fresh air volume of the central air-conditioning system is constant, and it is not possible to adjust the fresh air volume according to the actual flow of people. It is recommended to adjust the amount of air supply according to the indoor CO2 level so as to save energy consumption for fresh air treatment. There is no distinction between 24-hour operation and operating time-only operation in the air-conditioning hot and cold water transmission and distribution system. Therefore, the hot and cold water in the main pipe requires 24 hours of continuous circulation, resulting in the waste of water pump energy. It is recommended that reasonable divisions should be made according to usage conditions, such as outpatient service, office work, etc., which only operate during working hours. 2) Boiler equipment
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There is a need for domestic hot water all year round in the hospital's cafeteria and bathing room, but the capacity is only about 20% of a single boiler. In the non-heating season, the boiler operates at a low load rate and is thus less efficient. It is recommended to set up a air source heat pump unit that serves domestic hot water according to actual needs so as to improve energy supply efficiency. 3) Lighting system At present, the lighting of the medical building is mainly controlled by the personnel in each functional area, and the lighting control circuit in the public area is integrated. It can not be adjusted according to the needs of the subregions. It is recommended to use multiple channels to independently control the lighting in each public area, to rearrange the lighting in the well-lighted area, and to use the light sensor to automatically control the daylight switches to achieve energy savings. In addition, it is found that the garage lighting is always on for 24 hours even if in the period in which no car enters the garage. Besides, in the open area, the lights are turned on during the day, resulting in the waste of energy. It is recommended to use microwave induction system. Light sensing system is applied to the outdoor lighting of the garage, and the lighting is automatically powered off in the daytime. 5. Summary Energy-saving in hospital buildings is imminent. This article selects a typical comprehensive hospital in the hot summer and cold winter area as a case, analyzes the actual energy demand of the hospital building through the measured data, and puts forward reasonable suggestions on the energy consumption mode and the system improvement plan of the hospital based on the operating conditions. Compared with the climate zone (the hot summer and cold winter areas) and hospitals of the same scale (tertiary general hospitals), the hospital's energy consumption per unit area is lower than average. Its daily energy consumption is dominated by electricity, which accounts for 66% of energy consumption and is used in lighting, elevators, air conditioning and ventilation equipment; followed by gas (oil), etc. as the main energy source for steam, hot water, disinfection and washing, kitchens, etc. Among them, the medical building comfortable air-conditioning and cleanroom air-conditioning energy consumption account for more than one-third of the annual total energy consumption; the boiler system uses close to nearly one-fifth of the energy, lighting energy consumption also accounts for more than 14%. Therefore, air-conditioning, boilers, and lighting systems are the main directions for energy efficiency in hospital buildings. Combined with the actual operation situation, this article discusses feasible energy-saving suggestions. Acknowledgements The authors appreciate the support from the China National Key R&D Program (No. 2016YFC0700100) and the Zhejiang Provincial Natural Science Foundation of China (No. LQ17E080009). References [1] Barb Kaiser, Patrick D. Eagan, Hollie Shaner. Solutions to Health Care Waste: Life-Cycle Thinking and "Green" Purchasing[J]. Environmental Health Perspectives, 2001, 109(3):205. [2] Pinzone M, Lettieri E, Masella C. Proactive Environmental Strategies in Healthcare Organisations: Drivers and Barriers in Italy[J]. Journal of Business Ethics, 2015, 131(1):1-15. [3] Shen Jinming, Yan Mingming, Lu Wen. The Characteristics of Hospital Energy Consumption and the Disadvantages of Traditional Cold and Heat Sources[J]. Chinese Hospital Architecture and Equipment, 2008, 9(11):8-13. [4] ISO 12655:2013 Energy Performance of Buildings - Presentation of measured energy use of buildings [5] Energy Diagnosis Report of the Fourth Affiliated Hospital, Zhejiang University School of Medicine [6] "General Principles for Comprehensive Energy Consumption Calculation" (GB/T2589-2008) [7] Jiang Yi, Yang Xiu. Equivalent Power Method in Energy Analysis[J]. Energy of China, 2010, 32(5):5-11. [8] Zhao Wei, Di Yanqiang. Technical Guide for Green Transformation of Hospital Buildings[M]. China Building Industry Press, 2015. [9] Lu Wei, Chang Yanxin. Investigation on Energy Consumption and Its Influencing Factors of Hospital Buildings in Zhejiang Province[J]. Building Science, 2010, 26(4):48-51.