A Unified Adaptive Fanger's Model for Thermal Comfort in Tropical Countries

Abstract

Thermal comfort, which used to be a luxury in life has transformed into a necessity in modern lives. Tropical country such as Malaysia has hot and humid climate all year round. Much air conditioning is required in tropical countries to provide thermal comfort for indoor occupants. Fangers model is deterministic as it regards the heat fluxes across the boundary between humans and their thermal environment. Fangers model is adopted by ASRHAE Standard 55 in 1992 but it has over-predicted thermal preferences of those living in tropics. Malaysians who are used to hot and humid climates prefer warmer indoor temperature, as hypothesized in adaptive model. Adaptive model is said to predict thermal comfort more accurately than Fangers model as it relates the indoor comfortable temperature to outdoor air temperature. The objective of this research is to integrate the adaptive theories into Fangers model and to synthesize a new thermal comfort model which is expected to accurately predict thermal comfort in tropical countries. As the adaptive theory says that not all peoples thermal preferences are affected by thermal histories and contextual factors, the new model has proposed a broader operation range of PMV for air conditioner. The increment of PMV range from ±1.0 to ±1.17 for 80% satisfaction requirement is proved to applicable in Malaysia.