Experimental analysis and performance of an asymmetric inverted absorber compound parabolic concentrating solar collector at various absorber gap configurations

The performance of an asymmetric inverted absorber line axis compound parabolic concentrating collector (IACPC) was evaluated under a solar simulator. The IACPC had a concentration ratio of 2 and a maximum length-to-width ratio of 2.5 with provision to adapt from an untruncated collector to a half height truncated version. The selectively surfaced absorber/receiver was copper sheeting onto which was reverse-bonded tubing along the long axis of the IACPC. High reflectance film covered the aluminium substrate of the collector. Water was the heat transfer fluid flowing in the system. Stagnation and efficiency tests were undertaken for the full and truncated versions of the IACPC at various absorber gap heights to determine the optimum performance and absorber gap configuration. Overall performance is marginally better for the higher gap height absorber configurations than for the lower at the range of collector water inlet temperatures of 20 – 70 °C.