فهرست نشریات علمی دسترسی آزاد ایران

This study investigates the combined impact of roofing materials and solar thermal collector systems on the energy performance of a mid-rise residential/office building located in Beijing, China. The thermal properties of roofing materials, specifically thermal emittance and solar reflectance, critically influence the building's thermal balance and thus its heating and cooling energy demands. Solar thermal collectors contribute actively by harnessing solar energy for domestic hot water and space heating, reducing reliance on conventional energy sources. Using detailed thermophysical properties of building components and a comprehensive HVAC and solar system model, the energy consumption patterns are simulated over the summer months. Results indicate that variations in roof thermal resistance (R-value) moderately reduce heat conduction and lower cooling loads. Solar collectors demonstrate a stable efficiency pattern driven mainly by radiation and load demand, largely unaffected by changes in roof R-values. The integration of high-reflectance roofing with solar collectors provides complementary benefits, reducing overall electrical consumption and peak loads. Collector performance fluctuates with variations in solar input and hot water usage, highlighting opportunities for control strategy optimization, such as setpoint management and pump flow regulation. The present results indicate that increasing roof insulation R-value from 1.8 to 2.4 m²K/W can reduce daily cooling energy use by approximately 15–20%, contributing to seasonal savings of up to 18%. When combined with high solar reflectance roofing materials and optimized solar thermal systems, total cooling load reductions exceed 25%, while peak electric demand decreases substantially. This research highlights the importance of integrating roofs and solar systems in enhancing building energy efficiency, providing guidelines for design and operational improvements in similar climatic zones.