CIBSE Technical Symposium 2016 Deep energy retrofit An Analysis of Energy Efficient Retrofit Strategies for Office Buildings in China Miss Xinyi Li, Chongqing University Professor Runming Yao, University of Reading Edinburgh, UK
Acknowledgments Other Co-authors: Shiyu Han, University of Reading; Baizhan Li, Chongqing University; Changqing Lin, Chongqing University.
Outline Introduction Modelling method - Scenarios setting - Core technology bundle - Climate conditions - Building classification - Building model Results and analysis Summaries
Rapid development Introduction 1981 Urbanization rate: 20.2% 2013 Urbanization rate: 53.7% Average GDP growth rate 9.9% Reference: NBS 2014
1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 Million squaer meters Introduction Building stocks and energy usage The annual building floor area completed 4,000 3,500 3,000 2,500 2,000 1,500 Total non-residential building floor space completed Total residential building floor space completed Total building floor space completed 27.5% 1,000 500 0 Reference: NBS 1997, NBS 2014, THUBERC 2014, MOHURD 2014
Introduction Building retrofitting achievement Building retrofitting during Chinese 11th Five Year Plan(FYP)(2005-2010) were mainly focused on residential buildings in northern central heating area, 1820 million m 2 of total building area were achieved at that period. 510 million m 2 of existing buildings had been planned to be retrofitted during the 12 th FYP (2011 to 2015),including 60 million m 2 of public buildings, 50 million m 2 of southern residential buildings and 400 million m 2 of northern residential buildings. During the first three years of the 12 th FYP(2011 to 2013), 620 million m 2 of existing buildings were retrofitted to improve building energy efficiency. Reference: MOHURD 2012, Wang 2014, NPC 2014
Introduction Building retrofit technologies Building envelope Insulation (wall, roof, slab et al.) Window updating (multiple glazing, Lowe coating, shading system) Air tightness Building services Lighting upgrade Energy efficient equipment Control upgrade Heat recovery Human factors Comfort requirement Occupant activities Access to controls Management and maintenance
Introduction Building retrofit types in China Envelope retrofit External window retrofit Internal heating and metering system retrofit External heating supply system retrofit Retrofit on ground source heat pump Reference: Shui & Li, 2012
Introduction Building age band 2011-2013 17.3% Pre 1981 2.7% 1981-1990 15.2% 2000-2010 39.3% 1991-2000 25.5%
Scenarios setting Scenario 1: Baseline Case. The baseline scenario is based on the typical 1980s building envelope construction and system performance. Scenario 2: Current Standard Case. This scenario describes the 1980s building that been retrofitted using the core technology bundle to meet all the current standards. Scenario 3: Deeper Retrofit Case. This scenario is about deep retrofitting of the 1980s building by introducing advanced technologies to further reduce energy consumption.
Core technology bundle Enhancement of the building insulation (roof, slab, external wall and external window) and air tightness. Improvement of the efficiency of lighting systems and equipment (lamp type, equipment power efficiency). Improvement of HVAC system efficiency (boiler and chillier). Application of advanced technologies including daylighting control and heat recovery (for Scenario 3 only).
Reference: MOHURD. 1993 Climate conditions Harbin Beijing Shanghai Kunming Guangzhou
Chinese climate zone Climate conditions Coldest mean monthly temperature Hottest mean monthly temperature Representative city Very cold -10 25 Harbin Cold -10-0 18-28 Beijing Hot summer and cold winter 0-10 25-30 Shanghai Mild 0-13 18-25 Kunming Hot summer and warm winter > 10 25-29 Guangzhou Reference: MOHURD. 1993
Chinese building classification Buildings Civil Buildings Industrial buildings Residential buildings Public buildings Office buildings Reference: Li &Yao. 2012, Li &Shui 2015, MOHURD 2015
Office building classification Office type Typical characteristics Outward appearance 1. Naturally ventilated, cellular (1) A simple building, often (but not always) relatively small. (2) Typical size ranges from 100m 2 to 2. Naturally ventilated, open-plan 3. Airconditioned, standard 4. Airconditioned, prestige 3,000m 2. (1) Largely open-plan but with some cellular offices and special areas. (2) Typical size ranges from 500m 2 to 4,000m 2. (1) Largely purpose-built and often speculatively developed. (2) Typical size ranges from 2,000m 2 to 8,000m 2. (1) A national or regional head office, or technical or administrative centre. (2) Typical size ranges from 4,000m 2 to 20,000m 2. Reference: DETR. 2000
Building Model 24-story prestige air conditioned office building South-north orientation 20mX48mX78m Total floor area: 230,400 m2 (large-scale office building) HVAC system configuration: four-pipe fan coil + dedicated outdoor fresh air system Available from 7am-8pm on weekdays
Annual site energy consumption kwh/m2 450 400 350 300 250 200 150 100 50 0 Results and analysis Annual site energy consumption 62.8% 83.2% 57.0% 76.5% 53.1% 68.8% 45.3% 61.2% 45.1% 59.7% S1 S2 S3 S1 S2 S3 S1 S2 S3 S1 S2 S3 S1 S2 S3 Harbin Beijing Shanghai Kunming Guangzhou Heating Cooling Lighting Equipment Fans, pumps and controls
Annual source energy consumption kwh/m2 Simulation results Annual source energy consumption 450 400 350 300 250 200 150 100 50 0 54.7% 49.0% 45.4% 40.0% 43.3% 73.5% 66.4% 60.6% 55.9% 58.0% S1 S2 S3 S1 S2 S3 S1 S2 S3 S1 S2 S3 S1 S2 S3 Harbin Beijing Shanghai Kunming Guangzhou
Summaries Strategic studies about the feasibility of retrofitting plans by applying the core technology bundle to mitigate the energy consumption in existing air-conditioned buildings to meet the current building standards. Retrofitting by using a single measure can not achieve the current building energy standard. Core technology bundle is the ideal solution for office building retrofitting.
Summaries 1980s AC buildings can achieve 45.1% to 62.8% site energy saving by implementing core technology bundle. Deeper retrofitting can save further energy (59.7%-83.2% site energy). However, deeper retrofit and advanced technologies are also associated with higher initial cost; hence an economic cost analysis should be considered before the final decision is made.
Bibliography (1) NBS. China statistical yearbook. Beijing: China Statistic Press, National bureau of statistics of China; 2014. (2) NBS. China statistical yearbook on investment in fixed assets (1950-1995). Beijing: China Statistic Press, National bureau of statistics of China; 1997. (3) THUBERC. Annual Report on China Building Energy Efficiency. Beijing: China Architecture & Building Press; 2014. (4) MOHURD. Report of Chinese Building Energy Efficiency Development-Existing Building Retrofit. Beijing: China Architecture & Building Press; 2014. (5) Shui, B., Li, J. BUILDING ENERGY EFFICIENCY POLICIES IN CHINA. GBPN, ACEEE, 2012. Global Buildings Performance Network (6) Wang, J. The current development situation and research prediction in Chinese existing green building retrofitting. Retrofitting of Existing Buildings Yearbook. 1. Beijing: China Architecture & Building Press; 2014. p. 179-87. (7) MOHURD. The 12th five year plan - building energy saving special planning.: Ministry of Housing and Urban-Rural Development, People's Republic of China.; 2012. Available from: http://www.mohurd.gov.cn/zcfg/jsbwj_0/jsbwjjskj/201205/w020120531015852.doc. (8) NPC. Report of the State Council on the work of energy saving and emission reduction. The National People's Congress of the People's Republic of China; 2014. Available from: http://www.npc.gov.cn/npc/xinwen/2014-04/21/content_1860424.htm. (9) Ma Z, Cooper P, Daly D, Ledo L. Existing building retrofits: Methodology and state-of-the-art. Energy and Buildings. 2012;55(0):889-902. (10) MOHURD. Thermal design code for civil building GB50176-93.. 1993.Ministry of Housing and Urban-Rural Development, People's Republic of China (11) Li, B., Yao, R. Building energy efficiency for sustainable development in China: challenges and opportunities. Building Research & Information. 2012;40(4):417-31. (12) Li, J., Shui, B. A comprehensive analysis of building energy efficiency policies in China: status quo and development perspective. Journal of Cleaner Production. 2015;90(0):326-44. (13) MOHURD. Design standard for energy efficiency of public buildings GB50189-2015. 2015.Ministry of Housing and Urban- Rural Development, People's Republic of China. (14) DETR. Energy Consumption Guide 19 - Energy use in offices. Department of the Environment, Transport and the Regions, London., 2000.
Thank you for listening! Any questions? Professor Runming Yao r.yao@reading.ac.uk Xinyi Li amylee_lixinyi@163.com