Research On the Heat Output of Heliostat Field Based on Microelement Method

Abstract

The optimal arrangement of heliostat field is of great significance to energy utilization, and the rational arrangement of heliostat field is firstly to accurately calculate the heat output  of heliostat field. To calculate the heat output of the heliostat field, first calculate the optical efficiency of the heliostat. After geometrical optical analysis, the micro-element method and the cross-product method can be used to determine whether the incident or reflected light on each area of the micro-element is occluded by the shadow of the tower or other heliostats, so that the shadow occlusion efficiency can be calculated. Then using the transformation of the optical cone coordinate system and the mirror field coordinate system and the symmetry of the incident light and reflected light with respect to the normal vector of the heliostat, so as to determine whether the reflected ray falls into the receiving range of the collector. So the truncation efficiency of the collector is solved. Then the optical efficiency of the heliostat is obtained by the formulas of specular reflectance, atmospheric transmittance and cosine efficiency. Finally, using the normal radiation irradiance formula, the heat output of the heliostat field is obtained. The annual average heatoutput obtained by the formula is 38.5MW.