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

Ayaz Hosham,Tetsu Kubota

doi:10.3390/buildings9010022

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.

Highlights

The impact of buildings’ energy consumption on global warming is clear and major steps have been taken towards lowering the carbon footprint of residential buildings
Building microclimate is defined as one type of microclimate involving indoor spaces and spaces around the indoor spaces of a particular building, which is considered to be the extension of the indoor climate [7]
Overall, the maximum outdoor air temperatures were 32–34 ◦ C while outdoor relative humidity ranged between 50–80%

Summary

Introduction

The impact of buildings’ energy consumption on global warming is clear and major steps have been taken towards lowering the carbon footprint of residential buildings. Vernacular architecture has developed over time to create comfortable spaces by using passive and low energy techniques. The existence of diverse types of spaces is one of the important features of the building microclimate, distinguishing it from a single indoor climate [7]. A naturally ventilated wooden traditional house, which is commonly seen in the hot-humid climates, often creates building microclimate by utilizing various types and sizes of semi-outdoor spaces such as corridors, courtyards and patios and contributes to provide thermal comfort to the connected indoor spaces

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Conclusion