38. Comparative Study on the Insulation Performance of a Lightweight Planted Roof Module Based on Outdoor Guarded Hot-box Testing Method

Green roof has the advantages of energy-saving and ecological environmental protection effects with, however, insufficient investigations quantitatively, which will keep it from practical engineering projects. In this paper, based on the guarded hot-box testing method, the energy-saving and thermal insulation properties of two lightweight roofing insulation modules with Sedum lineare and light planting soil will be studied and compared in the outdoor climate. The experiments involved two operating conditions, i.e., with the air conditioning on and off, that both maintained the moisture content of the two modules the same. It was found that the air temperature within the guarded hot-box was lower than the outdoor air temperature by 5.4 °C for the roof module with S. lineare, and the temperature drop of 5.4 °C was 0.8 °C lower than that of the roof module with lightweight planting soil. The average cumulative power consumption of the module with S. lineare was about 0.27 kWh/m², which was 0.05 kWh/m² lower than that of the module with lightweight planting soil. The electrical saving rate of the module with S. lineare was at 15.6 % compared with that of the module with the lightweight planting soil.