I. Introduction
One of the main concerns today is energy generation, consumption and preservation. Since the reserves of fossil fuels are limited, the use of alternative energy sources need to be encouraged. Large part of the engineering community considers solar energy being one of the most perspective alternative sources, whether directly by using solar heat and light or indirectly by using the wind, tidal changes and similar effects generated by the Sun's emitted energy. Apart from considering sustainable sources, it is also important to improve the efficiency at which the energy is consumed.