Performance of Building Roofs on Energy Efficiency-A Review

The steep increase in energy demand mainly during the summer season for tropical humid climates has gained significant importance in this scarce condition of fossil fuels. This paper presents a review on different roof technologies performed with an aim to reduce the cooling loads during summer thus helping in energy conservation. Firstly it deals with green vegetated roof carried out in regions of hot humid climates. The green roof performance was explored by evaluating its effect on temperature fluctuations and heat fluxes during summer. The results showed that the presence of plants led to a decrease in temperature in the presence of green roof. The water usage and tolerance to stress at times of prolonged drought were also assessed for several types of plants suitable for extensive green roof systems. Other cooling strategies are use of reflective paints also called cool paints. The impacts of the application of reflective paint on a standard bare roof were analyzed by mainly monitoring reduction of roof surface temperature at different case study locations. Further performance of three kinds of cool paints and even cool black paints are studied for going deeper into the facts of cool paint potentials and limitations. Eventually comparative analysis between these two solutions is assessed by taking into account the several parameters that affect the final energy performances. (C) 2016 The Authors. Published by Elsevier Ltd.