Optimization of passive design measures for residential buildings in different Chinese areas

Passive design, which has strong dependency of climate and areas, is the most economical effective strategy for reducing energy consumption inside residential buildings. A total of 25 representative cities of China were selected for optimum analysis. This paper presents an approach in which the orthogonal method and the listing method are integrated to explore how energy consumption is minimized in residential buildings by optimizing 7 passive design measures for each city: wall thickness (WT), roof insulation thickness (RIT), external wall insulation thickness (EWIT), window orientation (WO), window-wall ratio (WWR), glazing type (GT), and sunroom depth/overhang depth (SD/OD). With the optimization, the passive design could reduce annual thermal load of building considerably, even could replace air-condition systems in winter for the areas with high solar radiation such as Lhasa. The results reveal that neighbor cities have the same optimal combinations and the similar effects of energy-saving measures. A total of 7 passive design zones were summarized in a map. The architect could be guided in his choice of appropriate passive measures directly from the map or handling of exact passive design by the optimal approach proposed in this paper for different areas in China.