Surface construction and optical performance analysis of compound parabolic concentrator with concentrating surface separated from absorber

For the S-CPC (Standard Compound Parabolic Concentrator, S-CPC) based on plane structure, the concentrating surface is connected to the absorber, and the temperature of the concentrating surface and the absorber is significant different during working. The local concentrated thermal stress can easily cause thermal deformation of the concentrating surface. The conventional solution is to form a gap between the concentrating surface and the absorber, which can effectively interdict the thermal stress. However, this would cause the light leakage from the gap, resulting the reduction of the optical efficiency of S-CPC. Therefore, the SCSA-CPC (Separation of Concentrator Surface and Absorber CPC, SCSA-CPC) without gap loss is studied in present research. The mathematical model of SCSA-CPC without gap loss is constructed by using non-imaging optical theory, the concentrating performance and working characteristics of SCSA-CPC are verified through experiments. The research also shows that the optical efficiency of SCSA-CPC is better than S-CPC, and the energy flux distribution on the absorber surface is more uniform. When the annual radiation collection amount of S-CPC is 2008.02 MJ/m2, the value of SCSA-CPC is 2009.00 MJ/m2. SCSA-CPC not only achieves the separation of the concentrating surface and absorber, but also slightly improves the collection capacity of solar radiation. •A Separation of Concentrating surface and Absorber CPC without gap loss is constructed.•Concentrating properties of SCSA-CPC are verified by a laser experiment.•SCSA-CPC has better optical efficiency compared with S-CPC.•SCSA-CPC has a lower peak energy flux and better uniformity.•SCSA-CPC could collect more solar radiation.