Effects of Bottom-Overhead Design Variables on Pedestrian-Level Thermal Comfort during Summertime in Different High-Rise Residential Buildings: A Case Study in Chongqing, China

Abstract

The design of bottom-overhead (or lift-up) buildings is advantageous in improving the thermal environment of high-density cities and enhancing the comfort level of occupants’ activity space on the ground floor. This study aims to investigate the impact of multiple architectural design variables on the ground floor overhead area of slab-like and tower high-rise residential buildings from the perspective of pedestrian-level thermal comfort with ENVI-met simulations and Standard Effective Temperature (SET*) evaluation. The design variables of the 25 tested models include the number of continuously arranged buildings, aspect ratio, overhead form, overhead space height, positions of overhead space enclosures, and openness degree, derived from existing overhead buildings in Chongqing. The results demonstrate that when the number of continuously arranged buildings and the aspect ratio increase, the overhead area has a more comfortable environmental state, while the overhead height is negatively correlated. In addition, when the enclosures are on opposite sides and their openness degree is 0.75–0.5, the area tends to be more comfortable. For slab-like buildings, the thermal comfort of the partial-overhead form is the worst while the semi-overhead form is relatively better. However, the overhead form has no significant impact on the thermal comfort of tower buildings. These findings can provide some suggestions and inspiration for the design of overhead buildings to create a more sustainable and livable microenvironment.