Modeling Thermal Losses in a New CLFR “Etendue-Matched” Non-Evacuated Collector Cavity

Abstract

A new CLFR concentrating optics has been proposed [1, 2] and patented [3] and a project is being initiated at the University of Évora, to test the concept on a scale of a collector field with a mirror area of about 530 m2. The goal will be to demonstrate the possibility of a collector instantaneous efficiency above 60 % at 450 °C, extrapolating from tests carried out to at least 400 °C. The present paper addresses the optical and thermal characterization of the second stage non-evacuated concentrator, an asymmetric TERC [4] type cavity optimized simultaneously with the étendue matched primary, after simulation results obtained with an integrated numerical tool designed for such purposes [5]. The presented optical and thermal losses results are a crucial guide for the final design of the proposed CLFR concept, prior to actual prototype production and installation for real performance tests.