Minimizing the Impact of Shading at Oblique Solar Angles in a Fully Enclosed Asymmetric Concentrating PVT Collector

PVT collectors produce both electricity and heat from the same area. PVT collectors with low concentration factor allow both stationary and tracking configurations. For stationary or single axis tracking, the daily variation in the solar incidence angle can cause significant shading in concentrating collectors. Shading has a larger impact on PV than on thermal collectors and thus the evaluations was more focused on the electrical part. Several prototype versions of a novel design for a concentrating asymmetric PVT collector have been tested and compared. One tested improvement was replacing the reflective end gables with transparent end gables. Another improvement was to use different cell sizes. These actions were expected to minimize the impact of the shading at oblique solar incidence angles. The second action was found to be more beneficial than the first. Measurements were also performed in the solar simulator to fully understand the impact of shading in cell strings with 1/6 the size of standard cells. The latest version of the PVT was found to have, at 25oC and 1000w/m, a collector efficiency of 13,7%, a cell area efficiency of 20,3% and an electrical power output of 237W. Lower side of the receiver was producing 58% of the total power. © 2013 The Authors. Published by Elsevier Ltd. Selection and/or peer-review under responsibility of ISES