Experimental analysis on heat mitigation potential of stacked coir fiber mat and perlite as an alternative for green roof

Depleting non-renewable resources and global warming motivated researchers to focus on passive cooling solutions to minimize the internal temperature of buildings. The benefits of using stacked coir mat and perlite in wet and dry conditions are tested for their cooling capacity compared to green roofs are explored in this research work. The benefits are quantified in terms of heat flow and temperature variations in a field experiment, and they are compared to a conventional bare roof in a tropical region in the Indian subcontinent (8.9142 ^o N, 76.632 ^o E). The heat transfer to the inside of the roof for dry coir mat paved, stacked coir mat and perlite bed, stacked wet coir mat and wet perlite bed, and extensive green roof system with coir mat as retaining layer are reduced by 38.43%, 63.21%, 55.3% and 56.97% respectively. This study evaluated the evaporative cooling capacity of wet coir mat and wet perlite, which have given almost near cooling capacity of green roof for 24 h. Considering its low maintenance and low initial cost, the usage of the stacked coir fibre mat with perlite shows a compatible reduction in heat transfer through the roof slab as that of the green roof. The coir insulation with perlite will undoubtedly reduce the energy requirement for heating ventilation and air conditioning (HVAC) systems to a greater extent.