Investigation of the Possibility of Intermittent Water Supply in Evaporative Air Coolers

This study investigates the performance of evaporative air coolers equipped with cellulose rigid humidifying panels, specifically focusing on the potential of intermittent humidification. Given the limited research available on intermittent humidification in evaporative air cooling, we establish a custom measurement station to evaluate the effects of panel drying on evaporation efficiency, which is closely linked to the cooling performance of the evaporative cooler. The findings reveal that upon stopping the pump, the evaporation efficiency reaches its maximum within 40–45 min, achieving 66.1%. During the drying process, the cooling capacity decreases significantly, with the total drying time reaching near-zero efficiency after 50 min without pump operation. Subsequent measurements confirm that reactivating the pump restores the evaporation efficiency to 65.2% after 30 min of continuous operation. The results indicate that intermittent operation of the pump can lead to energy savings, because the COPR inverse metric suggests that stopping the pump results in lower energy consumption compared with the additional electrical demand of an alternative cooling system, provided the COPR inverse value remains below that of the alternative system. The study concludes that a systematic approach to intermittent humidification not only sustains the evaporation efficiency but also optimizes energy use, thereby enhancing the operational strategies for evaporative cooling systems.