Research On Receiver Optimization Based On Linear Fresnel Reflective Condensation

Receiver is the important component of a solar concentrating system. The main function is to collect solar radiation and convert the sunlight into heat. Good or bad performance of a receiver will directly affects the temperature and efficiency of the system. Compared with some common solar receivers, such as a receiver with vacuum tube pipe and a cavity receiver, it was found that the receiver with a vacuum tube has higher temperature rise and efficiency of the system. But the cavity receiver and tube receiver are simpler in structure.Cavity absorber is simple in manufacturing and is also relatively easy in making and maintaining. Investigations showed that the cavity absorber in low temperature application has also good thermal efficiency and economic benefits. In this paper, the optical and thermal properties of the receivers with four different cavity structures, including isosceles triangle, square, isosceles trapezoid, semicircular absorber, were comparatively analyzed and verified through the Trace Pro optical simulation software. By comparing kinds of structure parameter, the triangular cavity absorber which has better performance in four cavity receiver was selected for optimizing its parameters. The performance of the triangular cavity absorber with different apex angles was discussed. For the cases the surfaces of the cavity are diffuse and specular reflection respectively, the triangle cavity with 56.7° of the apex angle has a relatively optimal performance. Through simulating the four absorbers under the same ray tracing condition, it was shown that semicircular cavity has highest flow density on the surface, triangle cavity has the highest total radiation, and heat flux distribution is the most uniform on the surfaces of the triangle cavity absorber.(1) By setting a Fresnel concentrator model with four mirror strip modules, the maximum flux density, the average flux density, total flux and the incident flux of the cavity receivers were simulated under the different solar irradiation. It was concluded that the optical efficiencies were the highest under the 90 degrees of incidence angle of the reflector mirror field.(2) The performances of the four cavity absorbers with the same opening width were simulated and analyzed, and the triangular cavity is has the best thermal performance.(3) By simulating and studying the average flux density on the inner surfaces, the total radiation flux and optical performance of the triangular cavity receivers with 150 mm opening width and different apex angles, it is concluded that the triangle cavity absorber with the apex angle 56.7 ° has the best performance.