Energy-efficient retrofitting in complex university buildings: energy consumption, exergy loss, entropy generation and life cycle greenhouse gas analyses

Abstract

This study examines the impact of energy-efficient renovation and reinforcement of the building envelope on energy consumption and carbon dioxide emissions in the Faculty of Arts and Sciences building at Balikesir University, a complex structure constructed in 1994. Energy consumption was evaluated through EnergyPlus simulations based on the thermal transmittance values recommended in TS 825:2013, which largely reflects the characteristics of the existing building stock in Turkey. The building includes various functional spaces such as classrooms, offices, laboratories, and storage areas, with window-to-wall ratios ranging from 13.6% to 38.02%, a total external wall area of 15,986 square meters, and a window area of 4,796 square meters. Fifteen renovation scenarios were analysed, involving upgrades to external walls, floors, ceilings, and windows in line with TS 825 standards. Each scenario was assessed for its effect on heating, cooling, and annual energy consumption. In addition, the exergy loss and entropy generation associated with energy consumption were calculated for the building envelope. The building operates with a central system, employing a natural gas boiler for heating and an air-cooled chiller for cooling. Finally, a ten-year life cycle analysis of greenhouse gas emissions was carried out using natural gas and electricity to assess environmental sustainability. The maximum reduction in energy consumption and carbon dioxide emissions, amounting to 45%, was achieved when all building envelope components were upgraded. The difference in exergy loss and entropy generation between the current case and the most efficient scenario was calculated as 58% during the heating period and 52% during the cooling period.