Experimental investigation of parabolic trough solar collector thermal efficiency enhanced with different absorber coatings

Abstract

The objective of this work is to investigate the thermal efficiency of a compound parabolic trough solar collector (PTSC) by using different absorber tube coatings. Two identical PTSCs were used to compare the different absorber coatings: one with matte coating (MC) and the other with nanocoating (NC) by adding Fe3O4 and graphene nanoparticles to the MC. In the beginning, similarity tests of the two collectors were carried out using the matte coating of the absorber tube under the same conditions and a mass flow rate of 120 L/h. The test results show the average thermal efficiency of collectors did not reach 0.11%. Then, the PTSC was compared with various mass flow rates: 30, 60, 90, and 120 L/h. The results show the maximum heat removal factor of PTSC for both nanocoating and matte acrylic coating at 120 L/h was 52.72% and 50.33%, respectively. And the maximum thermal efficiency of PTSC for both nanocoating and matte acrylic coating at 120 L/h was 41.58% and 40.37%, respectively. Finally, adding iron oxide and graphene nanoparticles to the matte acrylic coating has increased the amount of radiation absorption. As a result, PTSC's optical and thermal efficiency improved.

Keywords

• Parabolic trough solar collector
• Matte coating
• Nanocoating
• Thermal efficiency
• Experimental