Multi-objective Optimization of the Thickness of the Thermal Insulation and the Windows Area of a House in Benguerir, Morocco

This paper is dealing with a multi-objective optimization of the envelope parameters of a residential building located at the UM6P campus in Benguerir, Morocco. Precisely, the walls and the roof insulation thicknesses as well as the windows glazing areas are considered. The study's target is to check whether these parameters are well designed and, if not, to suggest better design for the ongoing houses similar to the studied one. To this end, three objective functions are considered, namely the heating and the cooling demands as well as the investment cost. The optimization methodology combines a well validated TRNSYS model of the house and the genetic algorithm NSGA-II of the multi-objective optimization tool MOBO. More than 2000 simulations were run, which allowed for identification of three optimal solutions. The best solution was that minimized the cooling energy needs. The corresponding insulation thickness is respectively 4 cm and 5 cm for the walls and the roof, which are almost half of the actual thicknesses (reference case); while the overall Windows-to-Wall Ratio is 11% instead of 17.4% in the real house. This solution reduced nearly half the cost of the investment related to thermal insulation and glass surfaces compared to a real home.