Solar thermal energy is the instantaneous transformation of the energy of solar rays into thermal energy. This transformation can be used directly, for example the heating of sanitary water using solar collectors, or indirectly in the case of the production of electricity in a solar thermodynamic plant. The solar thermal is based on the use of heat transmitted by radiation that is different from that of photovoltaic where electricity is generated by the energy of photons. With the help of technological advances, the techniques of direct capture of some of the solar energy are significantly improved in order to make the solar systems more reliable, efficient and profitable 1. The easiest way to utilize solar energy for heating applications is to convert it into thermal energy by using solar collectors. Solar air heater is one such method to convert solar energy to thermal energy.