Effectiveness of a discretely supported slab insulation system in terms of thermal performance

Abstract

One of the main issues of the thermal discomfort inside buildings is heat gain from building envelope. As a remedy, active cooling solutions such as air conditioners are commonly used. But that can never be admired owing to the contribution of excessive energy usage and environmental pollution. Hence, passive cooling solutions such as building thermal insulation can be taken as a fruitful solution. Since about 70% of heat gain of buildings occur through roofs, thermal insulation of roofs takes a prominent place in the aforesaid matter. As a result of rapid urbanization and population growth, the amount of usable land for building constructions is very low and the constructions have to be done on a very limited space. There, flat concrete roofs provide additional working spaces and the possibility of future vertical developments with other benefits such as extra robustness and the cyclonic resistance to the structures. Anyhow, utilization of flat concrete roofs is unpopular due to the thermal discomfort in the immediate space beneath. Addressing this drawback of ordinary flat concrete roofs, a new roof slab insulation system introduced having the capability of achieving more than 75% of heat gain reduction. Thermal performance comparison between the novel system and existing roof slabs confirmed the effectiveness of the new system. Further, 50mm thick vegetation was added on top of the novel slab system and thermal performance was compared. Results showed 20% of peak cooling load reduction from new slab system and 21% of peak cooling load reduction in a summer day under tropical conditions when it was vegetated.