Multi-Objective optimization of energy consumption pattern in order to provide thermal comfort and reduce costs in a residential building

Buildings, especially residential buildings, are the main energy consumers worldwide. Therefore, it is necessary to target existing buildings for intervention in this industry so that the adverse effects of buildings on the environment and economy can be significantly reduced. Considering the complexity of building energy calculations and energy pricing conditions in Iran, retrofitting buildings in terms of energy is a big challenge for designers and investors in this sector. In this research, to deal with time-consuming and complex calculations, MATLAB and Energy Plus software coupling is used to connect the optimization space to the modeling space. Also, to create a favorable trade-off between the project's economic conditions and technical and environmental factors, the three objective functions of energy consumption, thermal comfort, and net present value are simultaneously optimized by the NSGA-II optimization algorithm. HVAC systems, set temperature, roof and wall insulation, and window types are decision variables in this optimization problem. In the following, considering the energy subsidy in Iran, the effect of energy inflation on the objective functions was also investigated. The results showed that according to the current conditions of energy pricing in Iran, many optimal solutions are not profitable and the highest profitability of the project will be equal to 14,320 dollars. In this situation, the geothermal heat pump system with a performance factor of 2.3 and the split system had the highest number among the optimal responses. In the second scenario, all solutions are profitable and the highest profit of the project is equal to 31,846 dollars and energy consumption has reached 53,471 kWh. At the end and in the third scenario, the profitability of the project reached 83,117 and the reduction of energy consumption was reported as 27535. The geothermal heat pump system with a minimum share of 32% and the air-cooled chiller system were identified as the most used HVAC system.