Intervention to control cooling energy of west facing buildings: simulations from Colombo, Sri Lanka

Abstract

Optimum building influences to decrease the energy demand and enhance the indoor thermal comfort. Buildings facing west in tropics contribute to overheating and subsequently increase the energy demand. This may create a problem of energy oversupply difficulties due to rapid growth of construction, and exhaustion of energy resources and environmental aspects. This study was designed to assess the impacts of the outdoor shadings in order to control heat gain and indoor thermal comfort of west facing front façade buildings, in accordance with the fixed north-south orientation of street and a representative building typology in Colombo. Building namely, building orientation, façade direction, window to wall ratio (WWR), floor to floor height, room depth, were modeled for shade, and cooling load and comfort hours were simulated using the Ecotect software. Buildings were mainly considered into WWR>50% , WWR=50% and WWR<50%. Results suggested that 34.3%, 19.7% and 12.0% reduction of cooling load can expect in WWR>50%, WWR=50% and WWR<50% respectively, with outdoor shading. Optimum angle was found to be 45⁰ for tropics that has minimum cooling load. Outdoor shading with 45⁰ shading angle has a great potential to reduce the cooling demand independent to the different WWR of west facing front façade buildings.