Envelop insulation for energy efficient smart buildings in India

Abstract

The building sector is amongst the largest energy consuming sector across the world. Within the building sector, about 75 percent of the total energy is consumed by the residential buildings. The energy sector is directly and indirectly associated with greenhouse gas emissions, since majority of energy sector is dependent on fossil fuels, which are primary source of emanation. Building energy requirements are comprised of need for lighting, air conditioning and other home appliances operations. Air conditioning requirement is derived from the climatic condition in which a building exists. The building components such as walls, roof and windows are exposed to solar radiation and outside air temperature. Heat is conducted from exterior environment into the interior of the building envelop through these channels, wherein majority (approx. 60%) is conducted by walls and roof. Envelop insulation is considered as an efficient retrofitting measure to reduce heat gain from walls and roof, thereby need of air conditioning to remove that heat. In this work, envelop insulation has been designed for the Indian residential buildings existing in the three climate zones of India, i.e. warm-humid, hot-dry and composite climate zones. Electricity saving potential in an insulated envelop and associated life cycle cost saving analysis is carried out considering the application of four commercial insulation materials namely, expanded polystyrene, fiberglass, polyurethane foam and extruded polystyrene. It was concluded that at the design temperature 25˚C, annual electricity saving potential in retrofitted wall per unit area varies from 9 kWh to 16 kWh, whereas in case of roof it varies from 18 kWh to 28 kWh per unit area per year. Fiberglass is observed as the most cost effective insulation material, considering life cycle performance of the insulation material for all the climate zones.