The Design and Performance Analysis of a Solar Collecting System Based on Reflecting, Refracting and Reconcentrating Technics

A new type of solar collecting system has been designed with the advantages of low cost, less weight, compact volume and modularization. When beam of light reaches the surface of this modularized system, it will be reflected, refracted or reconcentrated by the different optical elements of system – Fresnel lens, mirror and secondary reflector. A vacuumed-pipe is used as receiver by placing at the focus of reflector to absorb concentrated solar energy and transfer it to heat transfer fluid. In addition, the secondary reflector is a key component that is newly-designed for corresponding to the new system, and its outline is compounded by a part of involute of circle and a part of parabolic, and is symmetrical on the left and right. In the course of design of reflector, some optical simulations are made besides theoretical design to make sure higher optical efficiency and lower solar tracking accuracy. In this study, a solar collecting system with lens, mirror and secondary reflector is presented and its performance is investigated. The optical efficiency is obtained under different incidental angles. Discuss the losses of system and find out the relation of efficiency and dimension parameters. It has been found that about 70% of the incident lights can still be gathered by absorber when the error of tracking is 2 degrees. Optical efficiency measurements have been carried out on a practical system of 4 meters long, 2 meters wide, 2 meters high, and the system is driven to real-time tracking. The result of experiment fundamentally agrees with the result of the simulation.