Effects of Building Microclimate on the Thermal Environment of Traditional Japanese Houses during Hot-Humid Summer

Abstract

The purpose of this study was to investigate the effects of building microclimate on the indoor thermal environment of traditional Japanese houses, focusing especially on the shading effect of trees as well as the cooling effect of spraying water. Basically, the indoor thermal environment was found to follow the outdoor conditions due to the open-plan and lightweight wooden structure. Nevertheless, air temperatures of the living rooms in the two case study houses were lower than the corresponding outdoors by approximately 0.5 °C and 2 °C, respectively. It was found that the semi-outdoor spaces acted as thermal buffers for promoting cross-ventilation as well as pre-cooling to provide “warm but breezy” conditions to the surrounding indoor spaces. The results showed that the surface temperature of semi-outdoor spaces can be reduced by shading and water spraying, among which shading has prolonged effects and water spraying can reduce the surface temperature during peak hours and the following night.

Keywords

• building microclimate
• traditional house
• semi-outdoor space
• courtyard
• thermal comfort
• spraying water