Integration of vegetation layer with lightweight foam concrete roof and active moving-air-cavity for attic temperature reduction

Abstract

The roof is the primary heat source for landed buildings since it is exposed to the sun. This will lead to significant heat gain in the attic, causing thermal discomfort for the indoor dwellers and increasing cooling loads. An ideal cool roof system plays an important role in inhibiting excessive heat gain and lowering the cooling load for attic temperature reduction. The experiment was conducted indoors by projecting two 500 W halogen spotlights at each roof model to replace the sunlight. The temperature of roof surface, attic, and moving-air-cavity (MAC) were measured using K-type thermocouples. The variation of temperature versus time for each roof model was compared against the predecessor design and base model. Significantly, with the cool roof model integrating vegetation layer, lightweight foam concrete roof tile, and active MAC with solar-powered fans, the attic temperature remained cool at 26.9 °C with a rate of 0.003 °C/min, 96.77% lower than the based model with reinforced concrete roof. The outstanding performance is due to the inventive cool roof system comprising the ability to minimize the heat gain while circulating the hot air efficiently in keeping the attic cool.