Improving building thermal performance through an integration of Passivhaus envelope and shading in a tropical climate

Abstract

Due to the success of the energy-efficient Passivhaus building envelope and its principles in regulating indoor thermal comfort in European climates, the potential implementation of it in other climates has been subjected to much attention in recent years. In this work, we adopted the hypothesis that slightly higher U-values of walls and floors than Passivhaus suggestion could be sufficient to achieve Passivhaus targets in the tropical context if the synergistic effects between shading and building envelope design were considered in a naturally ventilated condition.Firstly, thermal comfort thresholds were reviewed to establish the boundaries in the tropical context, choosing Myanmar as a case study. Secondly, Passivhaus steady-state calculation for shading design was compared with other dynamic simulation programs to inform the next step. The impacts of other parameters, which were excluded in Passihvuas’s PHPP calculation, were then investigated. Finally, thirty shading scenarios for ten different building envelopes were analysed in free-running modes using typical and future weather scenarios. The results showed that the hypothesis was true and 3.6% of annual overheating hours were reduced by coupling Passivhaus building envelope, thermal mass and shading devices, and also overall extremes of temperature were reduced by more than 2.4 K on the hottest day.