Heat Loss Measurements on Parabolic Trough Receivers

Abstract

A measurement set-up to determine the heat losses of single parabolic trough receiver components at steady state conditions has been developed at Schott. This paper describes the functionality of the set-up and a comparative campaign with three Schott receivers of 7.0, 8.9 and 11.1% emittance (400°C) including test stands at German Aerospace Center (DLR) and U.S. National Renewable Energy Laboratory (NREL). This campaign showed generally good agreement with deviations <10%. Additionally, results are compared to heat loss predictions derived from optical measurements of the absorber coating via a one-dimensional simulation. The general trend suggests good accordance with a systematical deviation at lower emissivities. Overall, this non destructive measurement technique provides a good possibility to determine an important receiver specification, its heat loss.