A water spraying box and its improving effect on the thermal environment around multi-story residential buildings to reduce released heat from air-conditioning units

The heat released from air-conditioning units is a cause to deteriorate the thermal environment around buildings, which is more serious around multi-story residential buildings. It is most effective to directly reduce the released heat from the air-conditioning unit in the mitigation of the outdoor temperature rise caused by the hot air from the air-conditioning unit. This study proposed a water spraying box as a simple and economic measure to mitigate the released heat from the air-conditioning unit. The cooling effect of the proposed water spraying box was investigated using experimental mock-ups. The experiment shown that the water spraying box installed on the air-conditioning unit can lower the exhaust hot air by about 10 degrees C. Numerical simulations were conducted to analyze the air temperature reduction around the buildings when the proposed spraying boxes were installed in multi-story residential buildings. The simulation results revealed that the average temperature of outdoor air around the building can be lowered by a maximum temperature of 2 degrees C when all air-conditioning units in the building were installed with the proposed water spraying box.