Geometric analysis and optimization of a parabolic concentrator for production at both thermal receivers at its focal point

Abstract

The exploitation of solar energy for the production of electricity through a thermodynamic cycle is done according to several methods. The parabolic concentration method remains the best because of its high thermal efficiency (about 68%) but the least used because of difficulties related to the storage of its energy. Our work concerns a parabolic reflector with two receivers at its focal point. These two receivers are a boiler and a Stirling engine. The boiler and the Stirling engine receive the energy concentrated by the reflector. In the presence of the Sun it is the Stirling engine that produces the electricity. During the periods when the solar energy is insufficient or absent it is the thermal tank that will send the heat to the fluid that will turn the blades of a turbine to produce electricity. To meet the thermal needs of these two receivers, the efficiency of the reflector's heat production must be improved. To this end, we have studied the possibilities of optimizing the geometric parameters of the parabolic concentrator. For a surface of 12.56 m2 of the reflector, the use of standard geometric parameters allowed us to obtain a daily energy of 824.474 kWh when the solar power is 1104.938 kWh. For the same surface, using the optimized parameters, the production increased to 975.937kWh; a gain of 13.7%. This study allowed us to discover that the geometric and optical parameters strongly influence the thermal production of a reflector.