Research On Evaporative Cooling Characteristics Of The Roofed Heat-insulation Module Under The Experimental Condition Of Wind Tunnel

With rapid economic development, China has become the world’s largest construction market. And among all building energy consumption, energy consumption of air conditioning accounts for about50%. Building roof is most heavily affected by the external environment. In summers, the incoming heat of buildings through roofs accounts for about36.7%of the total heat transfer of building. With the help of roof evaporative cooling technology, the incoming heat through roofs can be reduced, improving indoor thermal environment, reducing energy consumption, which possesses a good environmental ecological benefit and an economic benefit of energy conservation.This thesis purports to investigate evaporative cooling characteristics of light planting soil modules through a small-scale indoor analog experiment furniture of wind tunnel and find out the heat-insulation properties of sedum lineare modules and light planting soil modules through a comparative experimental study, which provides a scientific basis for the heat-insulation mechanism analysis and the engineering application of the roofed passive evaporation cooling.The analysis of evaporation characteristics:evaporation characteristics of modules are mainly influenced by external environment and the internal conditions of modules. External environment mainly includes ambient temperature, relative humidity, intensity of solar radiation, wind speed, etc. And the internal conditions of modules include construction and moisture content of modules. Through the experiment in this thesis, the mathematical model of the relationship can be presented as:W=A+Bt1/2between the cumulative evaporation of modules under the condition of no radiation and time. and the mathematical model of relationship can be understood as:W=A+BLn(t) between the cumulative evaporation of modules under the condition of radiation and time. Through the first derivative of cumulative evaporation, the mathematical model of the relation is deduced as:E=AeBTt-1/2between the environment temperature and the average evaporation rate with regard to time. The mathematical model of the relation between the environmental humidity and the average evaporation rate is deduced as:E=AeBSt-1/2The mathematical model of the relation between the radiation intensity and the average evaporation rate is deduced as:E=AeBFt-1. The mathematical model of the relation between the moisture content of modules and the average evaporation rate is deduced as:E=AeBω.The analysis of the heat-insulation property:In this paper, it can be presented that, under the condition of the same environmental, the moisture content of the light planting soil thermal modules is higher, the temperature amplitude of internal surface of the module is smaller. This shows that, with the external environment changing, the moisture content of the modules is higher, the temperature amplitude of the internal surface of module is smaller. Under the condition of the same environmental, compared to the same moisture content of sedum lineare and light planting soil thermal module, the temperature amplitude of the internal surface of sedum lineare thermal module is smaller. The last, by analyzing, the association of between the temperature of the internal and outer surface of module and the average rate of evaporation can be presented that the moisture content of the modules is higher, The influence of the heat insulation properties of the module is smaller by the evaporation.