Effect of highly reflective building envelopes on outdoor environment temperature and indoor thermal loads using CFD and numerical analysis

Abstract

In recent years, the climate change (CC) and urban heat island (UHI) effects are becoming serious problems, affecting people’s life and health, especially in hot summer. For large cities such as Tokyo and Osaka in Japan, the UHI effect is particularly intense. It is known that about 40% of urban anthropogenic heat comes from buildings in large cities. To reduce the anthropogenic heat of buildings is an important countermeasure to this problem. Strategies for UHI mitigation include urban ventilation, urban greening, green roof, highly reflective (HR) roads, and HR building envelopes, etc. Among these mitigation strategies, the research on HR building envelopes has been carried out globally. However, it is not clear that how the HR building envelopes affect the urban outdoor environment temperature and indoor thermal loads of urban buildings which is directly related to the selection of heating, ventilation and air conditioning (HVAC) system. Thus, this study aims to evaluate the effect of solar reflectivity of building envelopes varied from 0.1 to 0.9, on the outdoor environment temperature and indoor thermal loads of buildings located on Osaka University Suita Campus, Japan, using Computational Fluid Dynamics (CFD) and numerical analysis.

The Future of Climate-Resilient and Climate-Neutral City in the Temperate Climate Zone

“…Japanese researchers believe about 40% of anthropogenic heat comes from buildings [ 247 ]. This contributes to UHI intensity and the thermal comfort deterioration at the pedestrian level, and extends the duration of the elevated temperature [ 135 ].…”

“…Increasing the buildings’ energy efficiency and reducing their thermal emissions is necessary [ 197 , 247 ]. For this purpose, one can use location-related, orientation, greenery, building covering materials, and cooling or heating solutions.…”