Energy optimization of a residential building for electricity, cooling, and heating: A path to Net Zero Energy

This research investigates the feasibility of achieving a zero-energy residential building through the optimization of building design and the integration of a photovoltaic (PV) system. A 50 m² two-bedroom home in Fes, Morocco served as the case study. A sensitivity assessment using BEopt/EnergyPlus software analyzed the impact of materials and utilities on building energy consumption, costs, and savings. Parametric analysis identified closed-cell spray foam as the most effective for insulation and energy reduction. H-Gain low-E double-glazed insulated windows were found to be the most energy-efficient for energy savings. Additionally, a refrigerator with an EF of 19.9 was highlighted as highly efficient, consuming minimal energy relative to its cooling capacity, even in high-demand scenarios. Also, PVsyst was utilized for PV system design and energy generation analysis. The PV system produced 6325 kWh/year, with 5255 kWh used to meet energy demand, and 878 kWh/year excess energy not being used resulting in performance ratio of 68.88 % with a return on investment of 106.1 % and internal rate of return of 15.27 % with a payback period of 7.7 years simulated over 25 years period. The optimization process also contributed to substantial environmental benefits, avoiding 215.59 kg/year of CO2 emissions for the optimized building. This study demonstrates the potential for zero-energy residential buildings in Morocco, combining energy-efficient design with renewable energy solutions.