Heat transfer study of green roof in warm and humid climatic conditions

Abstract

Urban Heat Island (UHI) effect has become one of the major issues due to the increase in temperature the urban areas. Green roofs help to increase the thermal comfort of the building as they can reduce the heat flow through a building envelope. Since the vegetation acts as an insulating layer, the plants cover the roof, providing evaporation and transpiration cooling. In this paper, it has been studied the heat transfer through the conventional roof using experimental data and then constructed a numerical model for a green roof and performed simulations on the atmospheric conditions same as the experimental data, and observed that there is a decrease in the inside room temperature of the building installed with green roof in comparison to a conventional roof. From the simulations, concluded that there was a decrease in temperature during the peak hours. The results indicated that the green layer absorbs large amounts of solar radiation and releases it in the form of evapotranspiration (ET) and photosynthesis thus reducing the amount of heat penetrating the roof. With this inference, it is evident that the thermal comfort for the occupants is favorable and the cooling load and peak demand are reduced. This result is supported by the fact that the green layer absorbs large amounts of solar radiation and releases it in the form of evapotranspiration and photosynthesis thus reducing the amount of heat penetrating the roof.