Calculating Cost-Optimal Energy Efficiency Levels for Opening Elements on an Exemplar Residential Building

Abstract

This study presents a comprehensive approach to enhance the energy performance of a multi-story residential apartment in a temperate region of Turkey. The strategy focuses on cost optimization in compliance with EPBD Directives and CEN EN 15459-1:2017 standard. It addresses energy consumption and environmental impact associated with glazed building components and openings, considering key factors like primary energy use, energy costs, CO2 emissions, and annual heating, cooling, and lighting energy consumption throughout the year. The building energy simulation (BES)-based optimization process involves the design variables that exert a significant impact on energy efficiency. These variables encompass window size, window-to-wall ratio, solar shading systems, glazing material properties, window frame composition, and profile dimensions. EnergyPlus and DesignBuilder with genetic algorithms facilitate this process. The study explores trade-offs among design alternatives and identifies building envelope configurations that improve energy performance and reduce costs compared to the reference building. Compared to the reference case, the energy-efficient cost-optimum solution achieved savings of 23.7% in primary energy (29.1 kWh/m2), 21.4% in global costs (44.4 €/m2), and a 24.4% reduction in carbon emissions (above 8 kg/m2). These results emphasize the benefits of using simulation-driven optimization in early design stages to meet energy efficiency and environmental goals.