Modelling the impact of ground temperature and ground insulation on cooling energy use in a tropical house constructed to the Passivhaus Standard

Abstract

In tropical climates ventilation introduces high levels of moisture into dwellings, leading to raised values of indoor relative humidity and air temperatures, creating occupant thermal discomfort. The Passivhaus standard, by creating a super insulated and air-tight envelope, reduces heat losses and provides low energy comfort. This approach in tropical housing might be effective but could potentially increase mechanical cooling demand. This research investigated the effect of ground temperatures on thermal comfort and energy-saving in a tropical dwelling. Terraced houses in Jakarta, Indonesia were chosen as this a popular house type. IES VE software was used to study building energy use, and the Passivhaus software PHPP examined the application of Passivhaus criteria. Field measurements of air temperature and relative humidity were used to validate the software model. Analysis revealed that the building’s predicted air temperatures were affected by the assumed ground temperature models in IES. Good agreement between the measured and modelled values was achieved only when a particular ground model was chosen. Having validated the IES model, dwelling insulation and air-tightness levels were incrementally changed until they met the Passivhaus standard. Finally, the feasibility of meeting the Passivhaus energy standard for cooling in the modified tropical house was tested.