Application of Passive Cooling Techniques in Vernacular Houses to Modern Urban Houses: A Case Study of Malaysia

Abstract

The main purpose of this paper is to determine potential vernacular passive cooling strategies for improving thermal comfort of modern urban houses in hot-humid climate of Malaysia. Field measurements were carried out in two traditional timber Malay houses and two traditional masonry Chinese shophouses to investigate their indoor thermal environments and passive cooling techniques. The results of the former showed that the indoor air temperatures were higher than the outdoor air temperatures by 1°C during daytime under open window conditions and 2°C at night under closed window conditions on average. The results of the latter revealed that indoor air temperatures adjacent to small courtyards were lower than immediate outdoors by up to 5-6°C during daytime; at night, the indoor air temperatures maintained values similar to the outdoors. The small courtyards were effective to enhance night ventilation and nocturnal radiant cooling in the high mass shophouses. When assessed using an adaptive thermal comfort equation for hot-humid climates, the periods of indoor operative temperatures exceeding the 80% comfort upper limit in the Malay houses, Chinese shophouses, daytime ventilated and night ventilated terraced houses were 47%, 7-8%, 91% and 42%, respectively on fair weather days. By comparing these evaluations and relationships between indoor and outdoor thermal conditions of all houses, potential passive cooling strategies for the existing terraced houses including night ventilation, roof/ceiling insulation, window/wall shading, courtyard/forced ventilation, and microclimate and urban heat island mitigation were discussed.