Thermal Impact Investigation of Shaded Opaque Walls in Bangkok

Abstract

The effectiveness of overhang shading devices in mitigating solar radiation on opaque walls is crucial for passive building design in tropical regions. However, opaque walls commonly are side-lined in shading design due to a preoccupation with insulation properties, appearance, and aesthetics. Unprotected walls exposed to solar radiation maximize heat gain, while shaded walls decrease external heat gain and indoor temperature, resulting in improved indoor thermal comfort and well-being. This research employs EnergyPlus and SPSS to investigate the optimal design of overhang shading devices for opaque walls in Bangkok, Thailand. The investigation is divided into two phases: (1) determination of the optimal depth-to-space ratio of overhang devices based on a parametric study of 12 overhang configurations; (2) an evaluation of the ratio in reducing solar radiation. The findings demonstrate a relationship between the device depths and the wall solar radiation and indoor temperature. The optimum depth-to-space ratio is suggested as 1:1.15, which can lower the annual average indoor temperature by 3.53% (1.18°C) compared to the benchmark design. Deeper shading device depths than the optimum depth-to-space ratio can be applied, with a slight improvement in protective performance (and commensurately increased costs). This research underscores the importance of overhang shading devices as a performance-improving strategy for buildings in the tropical climate of Thailand.