Energy prices are increasing all the time. Further worldwide supplies of fossil fuels are decreased. These supplies will be exhausted in the future. Therefore, it is necessary to find new energy sources. The direct transformation of solar energy into electrical energy through the use of photovoltaic cells is one of the possibilities. The aim of this paper is to illustrate the working principle of the photovoltaic system FVS 2001E that is located on an external wall of a building of Tomas Bata University in Zlín.
We introduce a new method of solution of the light curves of eclipsing binaries based on the Wilson and Devinney ((1971) Roche model. We performed an interesting application of the procedure to the binary system TT Her.