Thermal Performance of Green Roof and Conventional Roof in the Warm Humid Climate of India

Abstract

The main source of heat gain is through the roof of the building due to the prolonged hours of direct solar radiation. Many studies suggest that green roof is an effective cooling strategy. The studies conducted in Europe, U.S., China and other parts of India yield different performance results due to the diverse geographical location and climatic conditions, which are quite different from that in the warm humid zone of India, and cannot be used as an effective reference. The goal of this study is to establish the thermal comfort characteristics and efficiency of green roof in comparison to a typical concrete roof in the climate of Trivandrum, through simulation and validate it with a scaled model for the months of March, April and May. For this study two cases were considered—a room with conventional roof and green roof. The methodology involves simulation and measurements from a fabricated prototype to find the indoor ambient air temperature and indoor surface temperature of the roofs and its validation. The indoor surface temperature of green roof is on an average 19% less than that of Conventional roof at peak hours. The annual simulation data for Trivandrum, Mumbai and Trichy were crossed compared and the results showed a substantial difference throughout the year which reconfirms that, the green roof is effective in a warm humid climate in terms of indoor comfort, reduction of indoor ambient air temperature during summers and keeping consistent temperature throughout the year.