Optimizing cooling and ventilation strategies for energy efficiency and thermal comfort in air-conditioned mosques under hot-humid climates

Air-conditioned mosques, which have large volumes and are used intermittently five times daily, face significant energy consumption challenges. This study investigated air-conditioning (AC) operation and ventilation strategies in a typical large-scale air-conditioned mosque in the hot-humid climate of Malaysia. Simulations were conducted to evaluate the impact of various AC operational scenarios and ventilation strategies on energy efficiency and thermal comfort. The findings emphasize that strategic modifications can yield significant energy savings without compromising worshipers’ comfort. A pre-cooling period of 10 min before prayers, except for dawn prayers, which require 20 min, demonstrates a 5% reduction in energy consumption. In an advanced scenario that integrates natural ventilation of lower (doors) and upper (clerestory windows) openings during dawn prayers, a 10-min pre-cooling period for other prayers, and an optimized adaptive setpoint temperature, energy savings of up to 15% can be achieved. Thermal comfort analysis shows that the mosque maintains thermal comfort during dawn prayer ventilation, with the upper opening, at an indoor temperature of 26–27°C and an air exchange rate of 3 h⁻¹. The results highlight the need to maintain indoor temperatures within optimal ranges to enhance occupant comfort while minimizing energy demand. This study has underscored the importance of integrating passive and active cooling strategies to improve energy efficiency in religious buildings with intermittent occupancy patterns.