Analysis of Energy Conservation Measures for Existing Residential Apartments in a Composite Climate

The residential sector in India is expected to increase over eightfold by 2050, from a 24% overall power consumption in 2016, owing to increased lifestyle, access to electricity and disposable income. This rise in demand makes it pertinent to consider the need to increase the energy efficiency guidelines for upcoming projects and enhance the efficiency of existing buildings. This study aimed to look at the possibility of energy-efficient retrofitting solutions for residential buildings in composite climate zones. A typical residential apartment of 148.6 m2 built-up area in a composite climate of Nagpur was analysed. The building's energy use was examined using Design Builder software, an occupant survey and energy bills for the previous five years. Seasonal climate characteristics of ambient temperature, relative humidity and solar radiation drive high energy demand in composite regions. Summer peak power consumption was 2–3 times higher than winter peak demand. This increased electricity demand raises electrical capacity redundancy, resulting in an uneconomical investment. The current study investigates the possibility of reducing energy usage by using energy-efficient retrofitting solutions in the existing residential building stock. The findings of this study revealed that by considering a combination of the best methods from each category of retrofit strategies, the building's annual energy usage decreased by 42.5%. The results from this study will help existing apartment owners apply retrofit strategies that will help reduce the investment in higher energy demand required during summer.