A model for hot mirror coating on solar parabolic trough receivers.

Parabolic solar troughs are amongst the most widely studied solar thermal technologies available today. Methods for improving efficiency include the use of selective coatings on the absorber which reduces dominant thermal radiation losses. In this paper, we model a different approach of reducing radiation losses: the glass cover around the absorber can be coated with a hot mirror film, which reflects infrared radiation back onto the absorber. In order to describe such a mechanism, it becomes necessary to model theoretically the long range thermal radiation interactions inside the receiver unit. Our model uses discretization of the active surfaces to account for all the dominant radiation interactions, and can be used in a simulation to establish a temperature profile for the receiver unit, from which thermal properties can be inferred. The results of the simulation are compared to existing simulations and experimental data, wherever possible. [ABSTRACT FROM AUTHOR]