Suitability of heat wave event definitions for assessing indoor overheating in current and future climate: A case study in China

As one of the biggest threats to building environment, heat wave events (HWEs) are the main external conditions that need to be considered when evaluating building overheating performance. However, there is no uniform definition of HWEs and most of them are not necessarily suitable for indoor overheating assessment. Therefore, an investigation is undertaken to explore the suitability of different definition of HWEs when assessing the extent of overheating in buildings. In this study, four HWE definitions are used to detect the HWEs in the three future scenarios for the three cities in different climate zones in China. The difference of the HWE characteristics is compared with the different definitions, and a definition of indoor HWEs is proposed. The relationship between indoor HWEs in prototype buildings and HWEs detected by different definitions is analyzed in specific scenarios. The results show that the relative HWE definition is more applicable than the absolute HWE definition. It is preferred to obtain a more continuous HWEs by using the average temperature to determine the threshold of HWEs than by using the maximum temperature. Relative temperature thresholds are more effective than absolute thresholds for synchronizing HWE and indoor overheating. Moreover, most severity HWE pose the greatest threat to indoor thermal condition, which can be used as the basis for selecting extreme hot year. As a result, the study shows that there may be 1–2 months of indoor overheating in passive buildings for these cities in the end of this century.