Research on Analysis Method of Shading and Blocking of LFR Field

¹ National Engineering Research Center for Technology and Equipment of Environmental Deposition, Lanzhou Jiaotong University, Lanzhou, Gansu 730070, China
² Key Laboratory of Opto-Technology and Intelligent Control of Ministry Education, Lanzhou Jiaotong University, Lanzhou, Gansu 730070, China

^* Corresponding author: clwang@mail.lzjtu.cn

Abstract

Shading and blocking problem is the main element restricting efficiency of a LFR system. The traditional analysis methods often need to build the models by using SolTrace, which results in the low efficiency. According to characteristics of single axis tracking of the LFR field, a plane right-angle coordinate system was established, and coordinate equations of reflectors at any time were deduced. Lengths of shading and blocking were got by tracking sun rays which fell on the reflectors and reflected the receiver passing through the adjacent reflector endpoints at any time. Offset caused by the solar azimuth in the shading and blocking area was got by geometrical optics. And then, the shading and blocking efficiency could be calculated. For the Puerto Errado 1 solar thermal plant, the shading and blocking efficiencies on vernal equinox hardly changed; on summer solstice, they were smaller at sunrise and sunset, and gradually stable and close to the value of spring equinox with the increase of solar altitude angle; they were smaller on winter solstice and the change with time were larger. The results of the calculations were good agreement with the simulation dates of SolTrace, and validity of the method was proved.