فهرست نشریات علمی دسترسی آزاد ایران

This paper presents an experimental investigation of the thermal performance, energy-storage capability, environmental impact, and financial feasibility of a dual solar air heater using paraffin wax as a phase change material (PCM) and a perforated absorber plate. The system was tested under actual winter weather conditions at airflow rates ranging from minimum 0.017 kg/s to maximum 0.032 kg/s to evaluate the useful thermal energy gain, heat loss, outlet air temperature, and overall thermal efficiency. The results show that at the optimal airflow rate 0.026 - 0.032 kg/s, the system produced approximately 32.36 MJ/day of net useful thermal energy—sufficient to raise the temperature of an indoor space of 2,677 m³ by 10 °C. A maximum thermal efficiency of 78% was achieved with a relatively low total heat loss of 205 W. In contrast, the maximum outlet temperature of 64 °C occurred at the lower airflow rate of 0.017 kg/s, which resulted in higher heat losses due to convection and radiative of 296 W. These increased losses caused a 10% reduction in thermal efficiency. Based on Iraq’s national thermal-energy emission factor of 0.95 kg CO₂/kWh, the system has the potential to reduce annual carbon dioxide emissions by approximately 1.86 metric tons.