Comprehensive Cost–Energy Evaluation of Wall Insulation for Diverse Orientations and Seasonal Usages

Abstract

An optimization study on thermal insulation applied to building exteriors has been performed in this research. Solar radiation has been considered while obtaining optimum insulation thicknesses for various directions. Analyses have been conducted not only for the cardinal directions (south, north, west, and east) but also for the intermediate directions (southeast, northeast, northwest, and southwest). Solar radiation received by vertical walls and cooling and heating degree day values have been computed according to directions. This research examines the most suitable insulation thicknesses for different seasonal usage scenarios, considering cooling, heating, and annual energy demands. Variations in energy cost savings, savings rates, payback periods, seasonal energy demands, and optimum insulation thicknesses for various wall orientations have been presented. Additionally, correlations providing the total cost based on the applied insulation thickness for each direction and various building usage scenarios have been determined. The results indicate that incoming solar radiation varies from 52.08 W/m2 to 111.82 W/m2 across different wall orientations, while energy cost savings range from 23.48 USD/m2 to 24.56 USD/m2, with savings rates between 69.8% and 70.3%. Payback periods range from 5.94 to 6.05 years. Depending on the wall orientation, optimum insulation thicknesses vary between 4.52 and 5.02 cm for heating, 1.56 and 2.09 cm for cooling, and 5.92 and 6.08 cm for annual energy requirements. The heating energy demands ranged from 54.8 MJ/m2 to 58.38 MJ/m2, while the cooling energy demands varied between 10.91 MJ/m2 and 12.08 MJ/m2, depending on the wall orientation. It has been concluded that the ideal insulation thicknesses for meeting cooling, heating, and annual energy demands vary depending on the wall orientation and the building’s use purpose.