“…Many investigations have been carried out to improve a performance of flat-plate collectors by concentrating solar radiation using reflector. A small part of those investigations has focused on a system of the flat-plate solar collector and flat-plate reflector (McDaniels et al, 1975;Larson, , 1980Hussein et al, 1999;Taha and Eldighidy, 1980;Tanaka, 2011Tanaka, , 2015Ekechukwu and Ugwuoke, 2003;Farooqui, 2015;Grassie and Sheridan, 1977;Bollentin and Wilk, 1995; http://dx.doi.org/10.1016/j.solener.2015.06.038 0038-092X/Ó 2015 Elsevier Ltd. All rights reserved. Hellstrom et al, 2003;Armenta et al, 2011;Kostić and Pavlović, 2012;Kumar et al, 1995;Pavlović and Kostić, 2015).…”