Cool Roofs

Cool Roof Demonstration Project: This is an experimental monitoring project that has been conducted by IIIT Hyderabad in collaboration with Lawrence Berkley National Laboratory, US. On a macro level, the major goal of this complete project was to understand the benefits from extensive application of cool roofs, through a micro level field experiment. This was achieved through field evaluations, model simulations, and knowledge transfer. LBNL earlier has a monitored the impact of reflective roofs on energy use of commercial and residential building in the United States. In this experiment a field study has been performed to monitor and demonstrate the effect of cool roofs in two buildings in Satyam Learning Centre, Hyderabad, India. Hyderabad being a composite climate with hot summers has a large potential for cool roofs. 2)Cool roof demonstration project at Nainital & Pantnagar The intent of cool roof demonstration project is to observe the effect of cool roof on indoor air temperature through reduction in heat flux. Institutional building located at Pantnagar and Nainital in different climatic zones are considered for this study. Parameters such as heat flux, roof surface temperatures and air temperature are monitored. This report summarizes the installation, initial data analysis and problems faced on-site during installation. Installations at both the sites were completed in three phases. Installation at Pantnagar site was done during first phase and Nainital site was completed during second phase. During the third phase, some problems detected at Pantnagar site were rectified. Findings reveal that cool roof helps in reduction of heat flux and surface temperature, thereby reducing indoor air temperature. 3) Effect of Cool Roof on Requirement of Roof Insulation in Office Buildings in India Introduction to the project: An analysis has been performed to understand the relevance and effect of roof insulation on HVAC energy consumption in top floors of buildings with varying roof surface reflectivity. Simulations were performed for varying roof insulation thickness, and roof Solar Reflectance (SR), over a simple perimeter and core block, with a typical day time office schedule, for various climates in India, using EnergyPlus. From the simulation results it was observed that the savings achieved by adding insulation had diminishing returns, and the insulation has negligible effect on cooling energy consumption in case of high SR roofs. In some cases, when the roofs are highly reflective (SR of 0.7 and 0.8), adding insulation led to increase in cooling energy consumption. Further, based on these results, this work also suggested that the Energy Conservation Building Code recommendations for the prescriptive method are to be revisited.

Faculty

1. Vishal Garg (Head)
2. Vishal Garg (Head)