Study of the energetic, exergetic, and thermal balances of a solar distillation unit in comparison with a conventional system during the distillation of rosemary leaves

Experimental study of the thermal performance of heat storage-integrated solar receiver for parabolic dish collectors

Parabolic dish collectors (PDC) efficiently produce hot fluids for medium-temperature applications. Thermal energy storage employs phase change material (PCM) due to its high energy storage density. This experimental research proposes a solar receiver for the PDC with a circular flow path surrounded by PCM-filled metallic tubes. The selected PCM is a eutectic mixture of KNO₃ and NaNO₃ (60%:40% by wt). At a peak solar radiation of about 950 W/m², the receiver surface reached a maximum of 300 °C. The modified receiver is tested outdoors with water as a heat transfer fluid (HTF). The energy efficiency of the proposed receiver is about 63.6%, 66.8%, and 75.4% for the HTF at 0.111 kg/s, 0.125 kg/s, and 0.138 kg/s, respectively. The receiver's exergy efficiency is recorded at about 8.11% at 0.138 kg/s. The receiver with a maximum reduction of CO₂ emission is about 1.16 tons recorded at 0.138 kg/s. The exergetic sustainability is analyzed using key indicators, like the waste exergy ratio, improvement potential, and sustainability index. The proposed receiver design with PCM effectively produces maximum thermal performance with a PDC.