Research and analysis based on a discretised model of fixed heliographs

This article proposes a concrete method for calculating truncation efficiency, called the sampling method, and applies it to the field of solar thermal power. The method employs a discrete mirror model to calculate performance metrics within a tower type heliostat field, taking into account factors that affect the heliostat's optical efficiency, such as cosine efficiency, shadow-blocking efficiency, atmospheric transmittance, and truncation efficiency. Experiments have shown that cosine efficiency is the primary factor affecting optical efficiency. The annual average value of cosine efficiency is 0.7544, while the average atmospheric transmittance is 0.9652. Additionally, the annual average shadow-blocking efficiency is 0.8471, and the annual average truncation efficiency is 0.8127. Therefore, the comprehensive annual average optical efficiency is calculated to be 0.4627. The annual average thermal power output is determined to be 28MW by utilizing the average optical efficiency of each heliostat and the locality's average normal direct radiation. The average output per unit area of mirror surface is 0.4504kw/m² .