Heat exposure mitigation in renovated nearly zero-energy dwellings during concurrent heat waves and power outages

Abstract

As heat waves increase in intensity and duration, the risk of heat exposure in dwellings in countries with mixed humid climates is expected to rise. The impact of heat waves on building performance has been extensively researched. However, building performance during concurrent heat waves and power outages needs further investigation to reduce the dependency on active cooling during critical infrastructure failures. This paper presents a simulation-based study of heat exposure risks for a nearly zero dwelling during a concurrent heat wave and power outage in Brussels, Belgium using weather data from field measurements. Combinations of promising passive design strategies like natural ventilation, cool roof, and solar shading were evaluated along key performance indicators like indoor overheating degree, standard effective temperature, exceedance hours, and heat index. The building performance results showed that existing building-level passive cooling renovation strategies like natural ventilation alone would not be sufficient to mitigate heat exposure with an indoor overheating degree of 0.59 °C. Therefore, they will require additional passive measures like solar shading using window louvres to mitigate heat exposure risks and lower indoor overheating to 0.19 °C. The findings provide unique insights that inform building renovation practices, setting the stage for future research on the topic.