Thermal Environment And Comfort In Public Space Of City With Hot-summer And Cold-winter

Urban public space is considered as an important and limited place for people carrying out outdoor activities. With the growing scarcity of urban land, the issue of how to use the public space effectively has been placed more attention on. The utilization of urban public space is affected by thermal comfort, while human thermal comfort depends on thermal environment. Therefore, the study on thermal environment and thermal comfort is significant for constructing high-quality public space.Thermal environment in public space of the city with hot summer and cold winter varies dramatically during the whole year, leading to human thermal comfort changing significantly. In this paper, according to the difference on the physical structure of public space, typical public spaces such as urban park, street, square and campus of Changsha with hot summer and cold winter were selected for a long-term experiment of thermal environment and thermal comfort. And thermal environment parameters and people’s subjective thermal reaction were collected. Then the method of statistical analysis was used to process the test data for studying thermal environment and comfort of urban public space.Firstly, four significant thermal environment parameters including air temperature, relative humidity, globe temperature and wind speed were analyzed, and found out seasonal characteristics of thermal environment in urban public space. Then the reasons caused the differences in the thermal environment of public spaces were explained. Secondly, the impact of the physical structures such as vegetation, water body, surface material and other factors on the local thermal environment of the public space was further analyzed. Thirdly, the effect of thermal environment on thermal comfort was developed and the relationship between air temperature and thermal sensation vote was discussed. Additionally, physiological equivalent temperature (PET) was used as a physiological basis and neutral PET in different urban public spaces were obtained.The results showed that:Thermal environment characteristics of different urban public spaces differ significantly. Vegetation has a significant impact on the local thermal environment. On the one hand, it reduces the ambient temperature and increases humidity. On the other hand trees block the air flow and reduce wind speed, also significantly reduce solar radiation intensity. Water body has a significant effect on reducing temperature and increasing humidity, and surface material has a significant influence on humidity. Thermal environment has an important effect on the thermal sensation vote. The difference in the characteristics of urban public.spaces causes great discrepancy in thermal sensation vote. The differences on thermal environment characteristics of urban public spaces lead to the significant divergence of neutral air temperature. Neutral PET of test sites in different seasons has discrepancy.The study also showed that to achieve a reasonable regulation on thermal environment in public space, it is necessary for the designer to take full advantages of the appropriate factors (plants, water, buildings etc.)...