Thermal comfort in air-conditioned mosques in the dry desert climate

In Kuwait, as in most countries with a typical dry desert climate, the summer season is long with a mean daily maximum temperature of 45 °C. Centralized air-conditioning, which is generally deployed from the beginning of April to the end of October, can have tremendous impact on the amount of electrical energy utilized to mechanically control the internal environment in mosque buildings. The indoor air temperature settings for all types of air-conditioned buildings and mosque buildings in particular, are often calculated based on the analytical model of ASHRAE 55-2004 and ISO 7730. However, a field study was conducted in six air-conditioned mosque buildings during the summers of 2007 to investigate indoor climate and prayers thermal comfort in state of Kuwait. The paper presents statistical data about the indoor environmental conditions in Kuwait mosque buildings, together with an analysis of prayer thermal comfort sensations for a total of 140 subjects providing 140 sets of physical measurements and subjective questionnaires were used to collect data. Results show that the neutral temperature (Tn) of the prayers is found to be 26.1 °C, while that for PMV is 23.3 °C. Discrepancy of these values is in fact about 2.8 °C higher than those predicted by PMV model. Therefore, thermal comfort temperature in Kuwait cannot directly correlate with ISO 7730 and ASHRAE 55-2004 standards. Findings from this study should be considered when designing air conditioning for mosque buildings. This knowledge can contribute towards the development of future energy-related design codes for Kuwait.