Comment on: “Experimental and numerical investigation on solar concentrating characteristics of a sixteen dish concentrator”. By Xia et al., International Journal of Hydrogen Energy 2012; 37(24):18694–18703

For the sake of discussion to concentrating characteristics of multi dish concentrator, a simple calculation method of layout is given. By comparative study, the key of designing identical multi dish solar concentrator is confocal is deduced. In confocal and suitable f/D ratio conditions the smaller receiving aperture could be ensured, and the compound paraboloid receiver is not necessary.