Evaluation of Convection Suppressor for Concentrating Solar Collectors with a Parabolic Trough

Sammanfattning: Absolicon Solar Collector AB in Härnösand, Sweden, develops concentrating solar collectors with a parabolic trough. In the solar collector trough, there is thermal loss due to convection. A convection suppressor was made and used as a method to reduce thermal loss due to convection in the trough. The objective of the project was to evaluate the convection suppressor for solar collectors with a parabolic trough and its impact on the performance (thermal loss characteristics) in two different orientations of the trough, horizontal and inclined. The performance of the solar collector was first measured without the convection suppressor; these results were compared to two previous quasi-dynamical tests of the solar collector performance made by two different institutes, Research Institute of Sweden and SPF Institut für Solartechnik (Switzerland). The comparison was made to validate the test results from the tests without the convection suppressor, which matched. Secondly, when the convection suppressor was made and tested in the two different orientations, the results of the performance with and without the convection suppressor was evaluated as well as the convection suppressor itself. The results showed a significant improvement of the solar collector performance in the aspect of reduced thermal loss when the convection suppressor was used, hence higher efficiency.