Optimal strategy for transition into net-zero energy in educational buildings: A case study in El-Shorouk City, Egypt

Abstract

This paper presents a conversion strategy from the conventional educational building to a net-zero energy building (NZEB) as a promising solution to be utilized in solving the energy problems. To implement such a methodology of retrofitting strategies, an educational building, located in Egypt, is selected as a case study. Different strategies are applied to reduce energy consumptions. The first strategy is lighting retrofitting through replacing conventional fluorescent lamps with more efficient LED lamps. The second strategy is cooling retrofitting through replacing the traditional split units of air conditioners (ACs) into solar ACs. The third strategy is involving a photovoltaic (PV) system and is integrated into the grid. To choose the most economical and friendly environmental renewable energy system (RES) to be incorporated into the building to transit into NZEB, a software tool called a hybrid optimization model for electric renewables (HOMER) is employed for this study. The optimal sizes obtained with the capital cost of the PV system and inverter, integrated into the building after improving its energy efficiency, are 140 kW, 120 kW with a capital cost of $98,000 and $30,399 for the PV kit and inverter, respectively. Also, the renewable fraction gained from the system is approximately 82%. Furthermore, the PV/grid system for the new load (after employing the retrofitting process) will take 24 years to pay back all costs of the system.