Development and test of an end reflector for parabolic trough collectors

Within the DLR-Project PAREX (<(PA)under bar>rabol (R) under bar innen <(EX )under bar>periment) it could be shown by experiments and calculations, tha t collector efficiencies of parabolic troughs can be increased by up to 2% by means of the use of an end reflector, which is placed at the north end o f each trough (in case of a north-south oriented plant at the northern hemi sphere). Calculations show that the intensity of the incident concentrated radiation on the surface of the absorber increases by a factor of two. A fi rst prototype of a 0,7 m(2) end reflector was tested at the DLR in the PARM ESAN (<(PA)under bar>arbol (R) under bar innen<(MES)under bar>s<(AN)under b ar>lage) test facility. The radiation profile around the absorber was measu red and compared to the calculated results. A second 6,4 m(2) end reflector was designed and built up at the LS-3 test loop at the Plataforma Solar de Almeria (PSA).