Analysis of a two-stage linear Fresnel reflector solar concentrator

The two-stage linear Fresnel reflector solar concentrator is analyzed via an in-depth study of an installed, nominally 220 KW{sub t} system. The concentrator includes: a primary linear Fresnel reflector comprised of curved mirrors and a secondary nonimaging CPC-type trough with a tubular receiver. The principal practical design options for the secondary concentrator are evaluated. In this paper, via a computer simulation which includes ray-tracing of the primary reflector, the authors evaluate the sensitivity of energy output to: concentrator optical errors, system geometry, tracking mode, and the option of using flat versus curved primary mirrors. The two-stage Fresnel concentrator can be considerably less expensive than the corresponding parabolic trough collector, but is found to deliver about one-fourth less yearly energy. However much of this difference could be eliminated through the use of higher-quality CPC reflectors.