Abstract:
Solar energy can be used for substitution of the depleting fossil fuels in thermal applications and electricity
generation through thermal route. For medium and high temperature applications, a system for collecting solar energy
at high temperatures was developed and built in this research work. The system, built at the center of development of
renewable energy of the Algiers, consists of a 2 60° included angle, R0 = 0.90 m diameter spherical reflector
with a cylindrical receiver filled with water, tracking reflector which moves into the focus following the sun's
movement. The system is capable of heating water or other fluids to temperatures above 350°C, thus making it
possible to obtain process heat for domestic use and to store solar energy in a compact and economical way. An
analysis of the system's optical characteristics was performed to aid in the design of the spherical reflector and
cylindrical receiver. The thermal performance of the system was analyzed. The effects of mirror reflection,
concentration ratio, heat transfer to the fluid (water), incidence angle, size and form of the cylindrical receiver,
environmental conditions (wind, ambient temperature), have been studied by means of thermal model.
The performance of the spherical reflector was tested by the temperature of the water. Total efficiencies (solar to
thermal) of 60%-70% were obtained for a wide range of temperatures up to 350°C. The results of the present
study show that it is possible to use the spherical reflector for systems requiring process heat and make possible
substantial utilization of solar energy and considerable savings relative to fossil energy in the sunny countries of the
world
