Space cooling in buildings in hot and humid climates: A review of the effect of humidity on the applicability of existing cooling techniques

The building sector is one of the biggest consumers of energy in many countries and in South East Asian region it accounts for around 30% of primary energy demand. This is mainly dominated by the use of air conditioning systems to provide space cooling for the building’s occupants. Energy intensive vapour compression systems consume over 50% of total energy used in buildings, increasing to 80% at peak times. In addition, air dehumidification is achieved by reducing the ambient air temperature below its dew point, which is far lower than the required comfort conditions in buildings, causing more energy waste for air reheating. In this paper various cooling techniques will be reviewed and their suitability to provide comfort cooling in the context of hot and humid climates discussed. Compared to vapour-compression system which offer good reliability and comfort control level, passive cooling techniques have also been developed as viable low carbon alternatives. Commonly, passive cooling technologies such as radiant cooling, ground cooling, evaporative cooling, etc. have been mainly used in dry and hot climate, however their adoption in humid climate poses a problem as ambient air moisture content is high. Techniques for water vapour removal from air using desiccant materials will be discussed as well the use of solar energy to reduce energy consumption.