Mike Carrell wrote: > Fresnel lenses can indeed be manufactured in large sizes and cheaply. The > tradeoff problem is that solar concentrators have to be sun trackers to some > degree, and that requires structure and mechanism of some kind, which is > expensive. Also, the collectors have to be kept clean or lose effciency. > Therefore, one solution is to increase the efficiency of the PV device so > that fewer are made, or make it so cheap it can be used as building wrap. > The former is costly, the latter inefficient.
This translates into more opportunities for the business of window washing. Harry
