Methodology Of Climatic Urban Design For Buildings' Energy Efficiency In Hot-summer And Cold-winter Area

Urban development without environmental consideration is bringing the deterioration of microclimate conditions (air temperature, wind, solar radiation...), which leads to highly increase building energy consumption especially for air-conditioning. Since the 1973-1974 world oil crises, it taught a big lesson to the whole world on energy supply. Nearly half of the world energy consumption is used to control the indoor environment.In our research, we are searching for and trying to specify the urban design strategies to mitigate the urbanization effect on building energy consumption. But there is little cooperation between urban design and urban climatology in either the theoretical or practical aspect, as a result, there is no systematic and efficient theory or strategies which take the microclimate conditions into account, especially in hot-summer and cold-winter area.Above all, we suppose that there are efficient urban design strategies in hot-summer and cold-winter area, which can be explored and extended for controlling and ameliorating microclimate conditions for buildings' energy efficiency.Above all, our research summarizes the significant findings in three aspects:urban microclimate investigation from urban morphology, urban morphology research based on urban climatology, urban design depending on urban climatology. The analysis of urban morphology is taken as a highlight in the literature review. It not only sets up the theoretical foundation for the methodology of urban forms, but also guides us to find the cooperation mode of urban climatology and urban design.For the methodology, we employ two numerical models:SOLENE from CERMA laboratory in France and Coupled simulation of convection, radiation and conduction from Kato & Ooka Laboratory, Institute of Industrial Science, University of Tokyo. To better understand the performance of the models, we have done the comparison study in two ways:filed measurement and numerical simulation. The different positions of these two models have been set:the thermal-radiative model of SOLENE is employed as a diagnostic tool to calculation the morphological indicators, the radiation calculation model of Coupled simulation of convection, radiation and conduction is employed to calculate solar energy performance and the cooling and heating load of buildings. Moreover, to understand how urban forms affect wind environment, and then affect buildings' energy consumption, we employ star CD for the simulation of wind environment, finally to obtain the modified convection heat transfer coefficient on each facet of urban district. At the urban district scale, through the cooperation of the two numerical models and simplifying the calculation method, we establish an integral analysis method from urban form diagnosis to cooling and heating load calculation. For the establishment of case studies, we take hot-summer and cold-winter areas as the research object, and then we develop two methods of urban morphology:urban form typology and morphological indicators. We study respectively the impact of different urban form factors on buildings' solar energy performance and cooling/heating load. These urban form factors are organized in three parts:1. basic urban form patterns in uniform layout (slabs, pavilions and courts),2. basic morphological indicators in uniform layout (plot ratio, main orientation, street width in X-axis/street width in Y-axis),3. urban form layout (horizontal non-uniform layout, vertical non-uniform layout). Finally, we employ the case studies of staggered rows pattern to analyze how urban forms affect wind environment, and then affect buildings' cooling and heating load through modifying convection heat transfer coefficient on the urban surface.For the results analysis, on the one hand, we study the impacts of urban form factors on buildings' solar energy performance and cooling/heating load, and then find the regulation of these impacts. On the other hand, we explore the differences and relevance on buildings' solar energy performance and cooling/heating load of each group of cases studies. Through the results analysis, we understand the impact of the basic urban forms patterns, the basic morphological indicators and the urban form layout on buildings' cooling/heating load, and find sensibility of cooling/heating load on the variation of these morphological indicators.Except pointing out the contribution of the results on climatic urban design, we also indicate the limitation of the results. Although the tendencies that have been found in the results are interesting, they are analyzed under the relevant conditions that are set up just for the case studies. Therefore, these regulations could be transmitted into urban design strategies under the limited conditions; they are not absolute regulation in all the cases. To treat numerous case studies of urban forms and to find the regulations in the results, we employ separated simulation method. The analysis of the impact of microclimate on buildings' energy consumption is just limited to the direct effect of urban morphology on available sunlight and wind.The research methods on the analysis of urban morphology are as worthy as the research results. Especially some derivative morpho-climatic indicators could be good diagnostic tool before complete simulation work. These methods of urban form typology and morphological indicators can be employed in the primary evaluation of environment in hot-summer and cold-winter area. They can help urban designers to better understand the climatic performance of urban forms, and guide them to find adaptive strategies for climatic urban design.