Case Study on Improving the Energy Performance of Existing Buildings Towards Net Zero or Nearly Zero Energy Building Transition

Abstract

The European Union introduced the concepts of Nearly Zero Energy Building (nZEB) and Net Zero Energy Building (NZEB) in 2010, leading to a shift in energy efficiency efforts in buildings, especially in response to increasing energy consumption. In this study, the current energy usage of an educational building with an approximate usable area of 20,000 m² and an energy consumption of 225 TOE (tons of oil equivalent) was thoroughly examined. Based on this analysis, efficiency recommendations were made. Beyond energy-efficient building applications, potential studies for Nearly Zero Energy Building (nZEB) and Net Zero Energy Building (NZEB) applications were analyzed in terms of emissions and costs.

The benchmarking results showed that the initial investment cost for nZEB applications in existing buildings is twice as much, and for NZEB applications, three times as much, compared to energy-efficient building works. It was observed that energy-efficient building, nZEB, and NZEB applications provide efficiency rates of 35%, 69%, and 100%, respectively. When comparing the costs of emission reduction per ton, the highest cost was calculated for NZEB applications at 107,274 TL, while the lowest cost was for nZEB applications at 96,252 TL.