The Possibility of Intermittent Water Spray Implementation in a Non-Porous Indirect Evaporative Cooler

Evaporative cooling is a sustainable and energy-efficient technology based on water evaporation to achieve cooling. It uses air (R-729) and water (R-718) as refrigerants, so its effect on global warming is limited. Recent research focuses development of porous heat exchanger surfaces to be used in evaporative cooling technology with intermittent water spray. However, non-porous surfaces were not investigated. Here, we present the possibility of implementing intermittent water spray in a non-porous indirect evaporative cooler. The experimental results show that it increases the cooling capacity when compared to the constant water spray for chosen outdoor air parameters (20–30 °C and 40–50% relative humidity). Also, the time after the outlet air temperature achieves minimum value (4–6 min) is presented for a certain non-porous heat exchanger. The maximum cooling capacity obtained without spraying is 25–64% higher than the cooling capacity in steady-state conditions under constant water spraying. The regression model approach is employed to describe the observation. The results introduce a new path in evaporative cooling technology development. They also create the possibility of improving the effectiveness of existing systems by modifying only the water system management, without any changes in construction or replacing the heat exchanger.