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, and + 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. Results indicate that the solar-integrated model reduces summer energy costs by approximately 20%, carbon emissions by 25%, and climate-induced economic losses by up to $30,000. Indoor environmental quality and energy productivity indicators improved by 15–20%, confirming the efficacy of solar-based systems in maintaining comfort under extreme conditions. However, cooling performance during peak summer hours revealed a 5–10% decrease in the 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.