An Estimation of Air-Conditioning Energy-Saving Effects Through Urban Thermal Mitigation

This chapter introduces the evaluation cases of the urban heat island (UHI) countermeasures that we conducted in Tokyo. As Tokyo is hot and humid compared to many European and North American cities, measures to mitigate the severe thermal environment have been considered. We evaluated UHI countermeasures on the urban/city block scale and have thus far reported the results in mainly domestic journals. The countermeasures include general-purpose methods that can be used in other areas. We therefore present our evaluation as a case study. First, we propose a method for quantifying energy consumption by taking into consideration the spatial and temporal distributions of both air temperature and human activities. Next, we propose an estimation method for fractional vegetation cover (FVC) and an urban climate simulation method using FVC data. We then quantified the UHI mitigation and energy reduction effects of urban greening. Since the results are only valid for Tokyo, it is important to carry out similar evaluations in cities where urbanization is progressing rapidly, using the methods proposed in this study.