Domestic air conditioning in Malaysia : night time thermal comfort and occupants adaptive behaviour

• Main Author: Bin Ja'afar, Mohamad Fakri Zaky
• Published: University College London (University of London) 2008
• Subjects: 693.8
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.674644

This is the first study of night time thermal comfort in Malaysia as well as the first study of sleeping comfort level. The focus of the investigation, the use of air-conditioners in homes clearly indicates a problem. Evidences of overcooling (76% of the cases) and sleep interruptions (45% of cases) to adjust control are found. In around 38% of the cases, the internal thermal profiles never reached a stable condition instead they keep cooling throughout the night until the units are turned off in the morning. The act of putting on a thicker, comforter type blanket, more of a psychological choice than a physiological need, during air-conditioned occupancy, results in people operating their air-conditioners at lower than the optimum temperature level. A thermal comfort field survey was conducted by monitoring 29 air-conditioned bedrooms, investigating the environmental conditions, the corresponding comfort perceptions and occupants' adaptive behaviour. Thermal neutralities and thermal acceptability for night-time occupancy in air-conditioned homes are established. Statistically significant difference is found between the neutral air temperature of normal blanket users (27.5 °C) and that of comforter users (25.2 °C). Thermal acceptability and comfort range for each group have also been established. A simulation study was conducted and it shows that the choice of using a comforter as opposed to a normal blanket results in an increase of up to 52% in the cooling load of a bedroom. This finding suggests that adaptive behaviour does not always result in less energy being used for comfort provision when active cooling is employed.