Research development of indirect evaporative cooling technology: An updated review

Driven by the economic outbreak and the growing demand of thermal comfort, the energy consumption of air conditioning (AC) keeps increasing promptly. Indirect evaporative cooling, as an energy-efficient and ecofriendly AC approach, attracts attention in recent years. However, this traditional technology has some drawbacks associated with its working principles. For instance, the limited output temperature constrains its application scopes. Insufficient evaporation due to the poor wettability on the wet channel surface significantly affects the cooling performance. This study provides an updated review of the research progress for solving these problems. Specifically, lower-temperature air can be produced by dew-point evaporative coolers. Innovative wicks with different materials strengthen the surface wettability as well as promote evaporation. Besides, hybrid systems and system optimizations can ensure cooling performance under hot-arid and hot-humid weather conditions. With the recent developments and foreseeable future opportunities to cope with these problems, IEC is expected to make more contributions to reducing the energy consumption of AC in buildings.