How is Building Energy Use Related to Occupant Behaviors and Building Usage Modes?

Wednesday, September 21, 2011, Noon
Building 50 Auditorium
Lawrence Berkeley National Laboratory

YouTube Video | Presentation (PDF, 1.2 MB)

Building energy data around the world have been provided based on statistical data combined with some case studies for both office and residential buildings. Very large differences in energy use have been found for buildings with same functions between different countries. Studies have been made to understand the reasons for these differences. It was shown that the differences are not due to the difference in technologies used in these buildings, but rather are caused by different usage modes and behaviors of occupants. A simulation model has been developed to model the building energy performance under different usages.

The results show how the large difference in energy use can be caused by occupant behaviors. According to the total energy that the earth can provide us to operate buildings for whole human settlement, we need both energy savings technologies and energy savings usage modes. However, further studies have discovered that most energy savings technologies are heavily reliant on actual occupant behaviors and building usage modes. Some technologies may show great savings with high-energy usage modes but cannot make any change when operated at low-energy usage modes. Some measures work very well when a building operates at low-energy mode but may raise energy use when operated at high-energy mode. What should be the reference usage mode when we evaluate building energy performance at the design stage or when we evaluate energy savings technologies? It is very important to correctly set up the reference usage mode according to real possible usage modes.

Yi Jiang

Yi Jiang

Professor, Tsinghua University, Beijing

Prof. Yi Jiang graduated from the Building Engineering Department, Tsinghua University, Beijing in 1977. After working two years at a Chinese nuclear base, he studied in Tsinghua University as a Master and then PhD student in the Department of Thermal Energy. He obtained PhD in thermal physics in 1985. Since 1985, he has been a faculty member of Tsinghua University. He worked at the Building Research Establishment of the UK for one year as an attached researcher in 1988. He has been involved in a number of international collaboration projects such as IEA ECBCS (Energy Conservation in Building and Community System) Annex 21, 25, 34, and 53. He is currently a voting member of the IEA ECBCS executive Committee and co-chair of the Annex 53. Yi is a professor of Tsinghua University, head of the Building Energy Research Center, and an academician of Chinese Academy of Engineering. He is also a member of the China energy consultant committee under the State Council, and a member of the China climate change consultant committee. His major research field is building energy efficiency. He is the chief editor of the annual report of building energy efficiency in China. He received four national science awards for controls of district heating system, liquid desiccant air-process, indirect evaporative cooling, and building energy simulation (DeST).