Experimental Investigation of Parabolic Trough Solar Collector Thermal Efficiency Enhanced by Different Reflective Materials

This experimental study presents the thermal efficiency enhancement of a parabolic trough solar collector (PTSC) system using different refractive surfaces and various mass flow rates. Two PTSC models were used to compare the aluminium sheet (AS) and silver chrome film (SCF) under the weather conditions of Hungary. Initially, similarity tests of the two collectors were carried out using the aluminium reflective surfaces with a mass flow rate of 90 L/h. According to the test results, the average thermal efficiency between collectors did not exceed 0.3%. Afterwards, the PTSC was compared with an evacuated U-shaped glass tube at different mass flow rates, namely 30, 60, 90, and 120 L/h. According to the experimental results, the maximum heat removal factor of PTSC for both SCF and AS at 120 L/h was 58.59% and 46.02%, respectively. Moreover, the maximum thermal efficiency with AS obtained for 120, 90, 60, and 30 L/h mass flow rates reached 27%, 22.84%, 18.9%, and 14.86%, respectively. Likewise, the maximum thermal efficiency with SCF at these mass flow rates attained 46.84%, 39.73%, 37.47%, and 33.68%, respectively. Conclusively, the PTSC thermal performance using SCF is superior to that of AS regardless of mass flow rate.