Computational comparison of a novel cavity absorber for parabolic trough solar concentrators

Abstract

Parabolic trough mirror plants are a popular design for the conversion of solar energy to electricity via thermal processes. The absorber of concentrated solar radiation can reach high temperatures (> 500 degrees Celsius) and is responsible for efficiency losses mainly via thermal radiation. We build on our previous work on hot mirrors to study an absorber with a mirrored cavity. The cavity absorber for the parabolic trough receiver is designed to trap solar and thermal radiations by reflecting them back onto the absorber very efficiently, which would otherwise be lost. This paper shows simulation results indicating that the proposed design can exceed the heat transfer fluid temperature compared to existing alternatives. Using a theoretical model we developed, we can infer the temperature profile for the receiver unit, from which efficiency parameters can be derived.