Multi objective planning for sustainable retrofit of educational buildings

Abstract

The sustainable retrofit options may significantly improve the energy consumption and the environmental impacts of the existing buildings. This paper presents a multi objective optimization framework to reach the minimum economic costs and Global Warming Potential (GWP) impact of existing buildings. New energy-efficient technologies for the supply side of the energy system are considered which may minimize life cycle environmental impacts of buildings. Two educational buildings in the campus of Sharif University of Technology are studied. The results show that utilizing reciprocating engine and exhaust-fired absorption chiller reduce the GWP to 133 tons (17.79% of reduction) and 190 tones (20.8% of reduction) of CO2 eq. for the first and second case studies, respectively. The results show that the existing energy systems in both cases are economically optimal. Moreover, the result of Pareto optimal frontier for both case studies describe the trades off between economic and environmental objectives. The findings of present work will guide the energy managers to minimize the environmental effects of educational buildings. This study implies the need for policy measures to retrofit the buildings based on a whole life cycle point of view, instead of the usual ways of giving sole importance to the operational impacts of buildings. With buildings becoming more energy-efficient during their operational stage, there is an urgent need for an increased focus on operational optimization considering the life cycle impacts of solutions including energy efficiency technologies and utilization of renewable energies.