Study On The Thermal Insulation And Cooling Performance Of The Enclosed Cavity Evaporative Cooling Roof

The air conditioning cooling load of the room on the top floor of the building is greatly affected by the roof.At the same time,when the indoor air temperature decreases in summer,the energy consumption of the air conditioning in the room can be reduced,and the thermal comfort of the human body can be greatly improved.In this paper,a novel enclosed evaporative cooling roof is studied.Through wind tunnel experiment,the thermal insulation and evaporative cooling performance of the enclosed cavity evaporative cooling roof module and the open evaporative cooling roof module in typical summer weather days in Guangzhou and Yinchuan are compared.And the heat flux distribution characteristics of the two modules in different regions are discussed and analyzed.The equivalent thermal resistance is obtained to evaluate the thermal insulation performance quantitatively,which provides experimental basis for the structural optimization and engineering application of water storage roof thermal insulation module.The results show:compared with the open evaporative cooling roof module,the enclosed cavity evaporative cooling roof module has better thermal insulation,while the bottom temperature of the enclosed cavity evaporative cooling roof module in Guangzhou is 4.9?lower in the period of 2:00-20:30.And the bottom temperature of the enclosed cavity evaporative cooling roof module in Guangzhou is 4.9?lower in the period of 2:00-20:30.In Yinchuan,the bottom temperature of the enclosed cavity evaporative cooling roof module is5.32?lower during 9:15-9:00(+1).The maximum delay time of the enclosed cavity evaporative cooling roof module is 268 minutes in Guangzhou,while the minimum delay time of the open evaporative cooling roof module is 9 minutes in Yinchuan.Based on the correlation analysis between the bottom temperature of the module and the outdoor meteorological parameters,it has been found that the bottom temperature of the open evaporative cooling roof module is significantly affected by the outdoor meteorological parameters.Among the different modules in various regions,the heat flux of the open evaporation cooling roof module in Guangzhou is the largest,which is 7.98W/m~2.The equivalent thermal resistance of each module are:the open evaporative cooling roof module was 0.09(m~2.K)/W in Guangzhou,the enclosed cavity evaporative cooling roof module came to 1.90(m~2.K)/W in Guangzhou,the open evaporative cooling roof module came to 0.01(m~2.K)/W in Yinchuan,the enclosed cavity evaporative cooling roof module came to 1.76(m~2.K)/W in Yinchuan.The equivalent thermal resistance of enclosed cavity evaporative cooling roof module is greater than that of the open evaporative cooling roof module,and the enclosed cavity evaporative cooling roof module has better thermal insulation in Guangzhou.