N. H. Wong, E. Tan & S. K. Jusuf
Bibliographic info:
Proceedings of the 34th AIVC - 3rd TightVent - 2nd Cool Roofs' - 1st venticool Conference , 25-26 September, Athens 2013

Public residential buildings in Singapore are designed as naturally ventilated. As climate changes, the indoor thermal comfort becomes critical as it depends greatly on the outdoor weather condition. The Predicted Mean Vote (PMV) model developed for Singapore (Givoni, et al., 2006) which depends on indoor air temperature and air speed is used to predict the indoor thermal comfort. The objectives are to determine the current level of PMV and the future level of PMV due to climate change, and to simulate whether proposed mitigation method on the building envelope can bring back the future PMV level back to current level.

The paper discusses the changes in the indoor air temperature, the indoor air movement and the subsequent thermal comfort due to the climate change by simulating two main typologies of typical public housing, i.e. point block (model Point) and slab block (model Slab), at three different heights of the building (level 2, mid-level and top-level), and under current (reference) and projected weather conditions (future). The 24-hour indoor air temperature is simulated in IES-VE, while the indoor air movement is simulated in CFD Fluent under four external wind scenarios, i.e. Northeast (NE) and Southwest monsoon (SW), ambient prevailing wind (Generic set) and a simulated wind in an estate (Local set).

The changes in indoor air temperature, indoor air speed and the compilation of PMV results are presented in the paper.

The simulation study shows that there is increase of the indoor air temperature, but no significant difference of the indoor air speed due to the climate change. The resulting PMV index shows that climate change causes longer duration of warm thermal discomfort throughout the day. Implementing a mitigation method proposed from other study on cooling load e.g. a combination of lower solar absorption for wall and roof surface, lower u-value of wall and lower shading coefficient of glass, the thermal comfort level on the Top level in each model in the future can be brought back to current level.