Employing the spray system to alleviate the thermal action of air-conditioning in summer

Widespread adoption of air-conditioning significantly enhances indoor thermal comfort in summer, but the heat dissipation from these outdoor units contributes to an increase in ambient air temperature, exacerbating urban heat island effects. Consequently, as outdoor thermal conditions worsen, the energy consumption associated with air-conditioning is likely to escalate. The spray system becomes a suitable choice due to the obvious advantage of heat absorption through the droplet evaporation. To assess the effectiveness of the spray system in reducing heat release, a comparative study was conducted between two identical buildings with the same air-conditioning system, but only one of which incorporated the spray system. Three installed locations are considered with the spray location in inlet (Case 1), outlet (Case 2) and both inlet & outlet (Case 3) of outdoor units. The results demonstrated the average temperatures of air outlet were reduced by 4.0 °C, 6.3 °C, and 7.9 °C for Cases 1–3, respectively, accompanied by a reduction in energy consumption of the air-conditioning system by 18.8%, 13.9%, and 37.3% respectively. The most significant benefits were observed when the spray location was installed in both outdoor unit inlet and outlet (Case 3). The spray system established a virtuous cycle in heat dissipation improvement, evaporation enhancement, and air temperature reduction.