Experimental Study on Optimal Layout and Design Parameters of Spray Cooling Ventilated Roof in Hot Climate Region

Abstract

Ventilated roof and spray water cooling are effective technical measures to control indoor air temperature and reduce building energy consumption in hot climate region. While, the cooling effect of the spray water cooling system in the ventilated roof is not very clear. In this study, a novel spray cooling ventilated roof consisted of a horizontal ventilated roof and a spray water cooling system is presented in this paper to control indoor air temperature and reduce building energy consumption. The influences of spray water flow rate, spray nozzle layout, spray direction, air inlet and outlet, and appropriate operation mode on the cooling effect of the spray water cooling system have been experimentally investigated by using a experimental spray cooling ventilated roof model. The experimental research results show that cooling effect of spray cooling ventilated roof first reduces and then fluctuates within a small range with an increase in the spray water flow rate. Spray nozzle layout has important influence on the cooling effect of spray cooling ventilated roof. Spray from bottom to top has the best cooling effect of spray cooling ventilated roof. Air inlet and outlet can enhance the cooling effect of spray cooling ventilated roof. The recommended spray water flow rate and spray interval is 0.3 L/min and 30 min in the practical application of the spray water cooling system in the concerned ventilated roof model, respectively. The research findings in this paper can provide beneficial suggestions for optimization design of the spray cooling ventilated roofs in real buildings.

Keywords: Ventilated roof, Spray water cooling, heat transfer, Nozzle, Thermal performance