Measurement of the Equivalent Thermal Resistance of Rooftop Lawns in a Hot-Climate Wind Tunnel

Abstract

In a very hot summer equivalent to a Guangzhou summer, the reduction of heat coming into rooms is very important with respect to thermal comfort and energy efficiency. The objective of this study is to investigate the evaporation cooling effect on a rooftop lawn. A hot-climate wind tunnel experiment was carried out in order to obtain and analyze the heat and moisture transport in the rooftop lawn. Furthermore, a calculation with the energy conservation equation was carried out using the results of the hot-climate wind tunnel experiment. The calculated equivalent thermal resistance and synthesis exterior surface heat transfer coefficient were in fairly good agreement with that in the design standard for energy efficiency of residential buildings in the hot summer and warm winter zone, while the average velocity in hot-climate wind tunnel equals the summer average outdoor velocity in Guangzhou.