Obtainment and comparative study of selective surfaces for low cost solar thermal collectors

Abstract

This paper describes the obtainment, deposition and test of selective surfaces based on granite powder and a mixture of granite powder with CRFO, as well as shows a describing of the testing equipment. The compounds to be deposited on the substrate were obtained by adding a binder and a flux to the granite powder. The selective surfaces were tested in a solar collector prototype wood made, with a glass cover, which reduces the convection heat losses. The temperature data was measured by thermocouple type K and stored in a computer. The results shown that this new selective surface technology based on granite powder could be part of the flat-plate collector market in the future, because the temperatures achieved were similar to that reached by commercials surfaces.