Numerical and experimental heat transfer analyses of a novel concentric tube absorber under non-uniform solar flux condition

The thermal performance of a novel concentric tube absorber for a conical solar collector (CSC) under forced convection was investigated by numerical and experimental analyses. In this system, the CSC assembly is mounted on dual axis tracking platform that can accurately track the sun position to get maximum concentrated solar radiation over the entire circumference of the absorber. Due to conical-shape reflector, the non-uniformity of the solar flux distribution along the absorber length is high; therefore, the non-uniform concentrated solar flux was applied to the absorber surface as boundary condition in Fluent software. To evaluate the heat transfer characteristics and performance of the system, heat loss and gain factors were derived from the novel concentric tube absorber while varying the flow rate. The concentric tube absorber of the CSC system was developed and analyzed with different operational parameters. The double-tube design provides the uniformly distributed flow and temperature symmetricity along the absorber length. The predicted results of the CSC system were in good agreement with the measured results.