Retrofit of renewable energy systems in existing community for positive energy community

The decarbonization of buildings and communities has become a requirement for sustainability. In this regard, South Korea has set a target of net-zero-energy buildings, wherein all public buildings with a floor area exceeding 500 m2 must cover 80% of the primary energy consumption using renewable energy systems by 2030. This study investigated the improvement and maximization of energy from renewable energy systems through energy sharing between buildings by retrofitting an existing community. The feasibility of achieving a positive energy balance was investigated via simulations. The existing community is comprised of two residential houses and two office buildings. Through the retrofit design planning of the existing community, the total capacity of renewable energy could be applied at 75.4 kW after renovation. Through simulation, power generation rates of the building integrated photovoltaic (BIPV) and photovoltaic and thermal (PVT) systems were analyzed. The renewable energy generation rates were 2.48 times higher when using BIPV and PVT systems. Therefore, the analysis of the annual energy balance of the community indicated that 46.2% of the surplus energy can be generated via renewable energy systems, compared with that of conventional community. Thus, the retrofit community can be renovated into a positive energy community.