| Green roof has good thermal insulation performance,which can effectively alleviate urban heat island effect,building energy consumption and atmospheric carbon dioxide concentration.In this paper,the thermal performance of green roof and its influence on building energy consumption are studied in Nanchang,a typical city in hot summer and cold winter area.The details are as follows:(1)According to the conclusions of previous researchers,the heat transfer models of the green roof are divided into three parts to describe.The heat transfer equations of green roof leaf layer,soil layer and roof layer suitable for hot summer and cold winter areas are derived.The calculation of relevant parameters in the green roof model is introduced.(2)The heat transfer models of green roof are solved with the energy consumption simulation software Energy Plus.An experimental platform is built to monitor the temperature of each layer of planting roof in real time.Finally,the accuracy of the established models are verified by comparing the measured data and the simulated data.(3)The green roof and the conventional roof are tested by setting up an experimental platform.The actual thermal insulation performance of the green roof is analyzed.The test results show that the green roof has better thermal insulation in both kinds of weather conditions in winter,especially at night.The green roof has better heat insulation in both kinds of weather conditions in summer.The green roof has greater thermal inertness in both seasons.(4)The influence of three parameters of soil thickness,soil density and LAI in the envelope structure on the internal surface temperature and energy consumption of the building is analyzed.The results showed that:1)In the simulation with soil thickness as a variable,the increase of soil thickness has a greater positive effect on the heat insulation effect in summer and winter.In the simulation with soil density as variable,the increase of soil thickness has a positive effect on the heat insulation effect in summer.In the simulation with LAI as the variable,the increase of LAI has a significant positive impact on the heat insulation effect in summer and autumn.2)Energy consumption simulation results show that the optimal configuration of green roof is that soil thickness is 150mm,soil density is 1700kg/m~3,and LAI is 4.Under this configuration,the total energy consumption of the building is 34.64k W·h/m~2,which can reduce the total energy consumption by 9.72%compared to the conventional roof building. |
