Study On Thermal Comfort And Passive Design Optimization Of Rural Dwellings In Qinba Mountains

With the development of urbanization and the improvement of rural residents’ lives,the problem of poor indoor thermal comfort in residential buildings is increasingly being paid attention to.At present,Chinese scholars have conducted a large amount of research on human thermal comfort in different regions of China,and established human thermal comfort models in different regions.However,from the existing results,it can be seen that a suitable thermal comfort model has not been established to describe the human thermal neutral temperature and thermal comfort range in the Qinba Mountain area,and a passive design strategy suitable for the Qinba Mountain area and meeting the thermal comfort requirements has been proposed.Taking rural residential areas in the Qinba Mountains as an example,through investigating the thermal comfort feelings and current thermal environment of local residents,it was found that local residents have strong thermal adaptability and a wide range of acceptable temperatures.In terms of indoor thermal environment,there are problems such as hot and humid in summer,cold and humid in winter,and poor indoor thermal comfort.After summarizing and analyzing the characteristics of residential buildings and the performance of their exterior enclosure structures,it was found that there are four types of flat forms of local residential buildings: the "one" type,the "L" type,the "U" type,and the courtyard type,with the "one" type accounting for up to 40%;The maximum proportion of rammed earth wall in the external wall structure is 43.3%,and the heat transfer coefficient is 1.16 W/(㎡· k);In the roof structure,the maximum proportion of "cold tile" roof is 76.7%,and the heat transfer coefficient is 2.74W/(㎡·k).By extracting and simplifying the morphological features of residential buildings to establish a benchmark model,Ladybug Tools were used to conduct single factor simulation analysis on passive designs such as residential orientation,attic height,eaves width,peripheral protective structure construction,and sunlight depth.The simulation results show that to improve the indoor thermal comfort of local residential buildings,the orientation should be kept at-10～15 °,the attic height and cornice width should be increased,the heat transfer coefficient of the exterior envelope should be reduced,and the window wall ratio should be increased.Finally,taking the indoor thermal comfort duration as the standard,the arrangement,combination and simulation analysis of the passive design of residential buildings are carried out by using orthogonal and range experiments,and the optimal scheme suitable for rural residential buildings in Qinling Bashan Mountains is that the heat transfer coefficient of the external wall is 1.05 W/(㎡· K),that is,the external wall structure is: 20 mm straw cement mortar+50mm straw mud+400mm rammed soil+20mm straw cement mortar;The heat transfer coefficient of the roof is 1.49 W/(㎡· K),that is,the roof structure is: 20 mm roof tile+50mm grass mud+30mm wood watchboard+30mm wood roof frame structure;The southbound window to wall ratio is 0.2;Select 6mm single-layer glass window for window structure;The height of the attic is 1.8m;The width of the eaves is 0.9m.Afterwards,the optimized model was compared and analyzed with the benchmark model,and it was verified that it can effectively improve the indoor thermal comfort environment.Based on simulation results and optimization conclusions,this study aims to investigate the relationship between existing passive design technologies and indoor thermal comfort in the region,and provide a solution for improving indoor thermal comfort in rural residential areas of Qinba Mountain from the perspective of passive design optimization.