An Optimization Study on the Concept and Evaluation Methods of Residential Areas’ Building Shadow Ratio

Building shadow ratio is an essential indicator in the design of the thermal environment of residential areas in hot and humid regions, and a reasonable quantification of building shadows can accurately assess the shading status of the residential areas. The study analysed the relationship between building shadow ratio (gBSR), sky view factor (SVF), temperature (ground surface, air, and mean radiant temperatures), and thermal comfort index (UTCI). The results show that (1) there is a strong negative correlation between gBSR and SVF; (2) there is also a strong correlation between gBSR, SVF, and temperature and thermal comfort, but gBSR is stronger explanatory for UTCI than SVF; and (3) as SVF increases, or gBSR decreases, AT rises almost throughout the daytime, whereas GST, mRT, and UTCI are all on the rise during the daytime and then will gradually decrease. The study provides new methods for optimising the thermal environment of settlements from the perspective of building shadow.