Receiver optimization for an etendue conserving compact linear fresnel

Abstract

Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.

A Compact Linear Fresnel model can be optically optimized at two critical stages; the collector stage and the receiver stage. On the collector side, the mirror field can be designed according to the nonimaging optics principle of Etendue Conservation. The position and size of the mirror field is varied in order to create a system with minimal optical losses. This substantially increases the incident radiation and concentration of the receiver cavity, however the final absorbed radiation of the receiver pipes is dependent on the internal geometry of the receiver itself. Therefore, an optimization study was conducted on the internal geometry of a receiver paired with an enhanced mirror field. The receiver geometry included a parabolic secondary concentrator at the back of the receiver in order to reflect any missed rays. The optimization consisted of two objective functions; namely to maximize absorbed radiation on the receiver pipes and minimize standard deviations on the pipe surface. The results aligned well with theoretical optic calculations in terms of the expected focal point of the collector field and secondaries.