Multi-Objective Optimization of Building Design Parameters for Cost Reduction and CO2 Emission Control Using Four Different Algorithms

Thermal insulation applications on the exterior facades of buildings have been the subject of numerous studies from the past to the present. Some of these studies focus on the cost reduction effect of insulation, while others emphasize its ecological benefits. In this study, multi-objective optimization, the objectives of which are minimum cost and minimum CO2 emission, has been carried out with the NSGA-II method. In emission calculations, in addition to fuel-related emissions, the carbon footprint of all materials comprising the wall has also been included. The multi-objective optimization study examined four design variables: wall thickness, wall material (light concrete, reinforced concrete, and brick), insulation material (expanded polystyrene, extruded polystyrene, mineral wool, and polyurethane foam), and heating source (natural gas, electricity, fuel oil). Analyses have been carried out for four cities (Osmaniye, Bursa, Isparta, and Erzurum), which are located in different climatic regions, and considering solar radiation effects. An existing building has been taken as the base case scenario, and the study has determined the improvements in the total cost and the amount of CO2 released into the environment when the appropriate insulation material, insulation thickness, wall material, and heating source identified in the multi-objective optimization study have been used. At the cost-oriented optimum point in the study, the most suitable insulation material was found to be expanded polystyrene, the most suitable wall material was brick, and the most suitable heating source was natural gas. In the CO2-oriented optimum, in contrast to the cost-oriented approach, optimal results have been obtained when light concrete was selected as the wall material.