Study On Energy Consumption Features And Real Performance Of Public Buildings

Along with China’s urbanization and the development of tertiary industry, gross area and energy consumption of buildings are increasing rapidly, under which background, green building was and will continue to be significant measurement in building energy conservation and mitigation. Limited studies on energy consumption level and quota of public buildings, espacially for different climate zones and building types, have prevented building energy efficiency (BEE) management from beening more efficient. Studies on real performance of green public buildings are much rarer.Under the circumstance, this study firstly depicted Chinese public buildings’ electricity use intensity (EUI) excluding district heating of 10 categories in three climate zones, following by comparison with developed countries of the U.S., UK and Japan. Secondly, energy consumption of green public buildings in China and the U.S. was summarized according to literature survey. Suzhou Industrial Park (SIP) and the University of California, Santa Barbara (UCSB) campus were chose as study cases to dissected the real performance and performance gap of green public buildings from several perspectives of sub-meter energy system, operation and management and indoor environment.From building type aspect, mall & market with EUI of 65-191 kWh/m2, hotel & food service building with EUI of 80-150 kWh/m2, health care building with EUI of 62-132 kWh/m2 and other building type with EUI of 37-162 kWh/m2, are energy-intensive constructions, and should be taken seriously on BEE regulation. For different climate zones, public buildings in Hot Summer and Cold Winter Zone consume more electricity than those in Cold Winter Zone. For government office buildings, their EUIs increase with building areas, and those in developed large cities have higher EUI than those in less developed small and medium-sized cities; buildings built in last century consume more energy than those built after 2000. In the whole, Chinese public buildings consume far less energy than developed countries, and show special distribution of "left-skewed & double peaks", namely most public buildings have low EUI while still a small fraction have high EUI.Green public buildings are more energy efficient than non-green public buildings in the whole, but show different EUI from each other. Case study results show that, one project in SIP shows performance gap of 50%, and all three projects in UCSB have performance gap of 18%-94%. Factors contributing to gap include underestimation and deviation of modeling for real operation conditions, and condensed occupancy and office equipment. Indoor lighting and thermal environment of case green public buildings were much satisfied, while ventilation was perceived as poor. From the aspect of occupants behavior, most occupants behave energy-efficiently, some improper behavior exist still. Besides, missing information between building managers and occupants can also prevent occupants from being more environmental friendly. Thus, green building development will still be effective routine to achieve sustainable development for public buildings, and they need green occupants and green managers.Policies of improving BEE for public buildings were provided, which include strengthening building energy design code for new construction, retrofit of existing buildings, building energy monitoring and report for government office buildings and large-scale public buildings, promoting green buildings and their operation performance.