Simulation-based assessment of solar-integrated systems for climate-resilient residential buildings in semi-arid regions

This study presents a climate-responsive framework for integrating solar energy into the cooling and heating systems of residential buildings in Mashhad, Iran-a city with an average solar irradiation of 5-6 kWh/m² per day. We modeled the Nafis 3 residential complex in two energy configurations, Non-Solar (conventional systems) and Solar (photovoltaic-integrated), across four seasonal profiles and four climate scenarios: baseline, + 1 °C, + 2 °C, and + 3 °C temperature increases. The study evaluates system performance across sustainability, environmental, economic, and reliability indicators, with a focus on fluctuations in cooling and heating demand. The results indicate that, compared to the Non-Solar model, the solar-integrated configuration reduces summer energy costs by approximately 20% (e.g. from about $7,500 to $6,000 per season), carbon emissions by 25%, and climate-induced economic losses by up to $30,000 annually under the + 3 °C scenario. However, cooling performance during peak summer hours revealed a 5-10% decrease in Energy Efficiency Index (EEI) and a drop in system reliability due to solar intermittency. This study presents a practical, simulation-based approach to support the integration of solar energy in cooling and heating strategies for climate-resilient residential infrastructure in semi-arid urban regions.