Preliminary Determination of Heliostat Field Range and Research of Receiver Depression Angle in Solar Power Tower

In solar power towers, the determination of heliostat field range is the groundwork of heliostat field layout, which is one of the most significant parts in plant design. The objective of this paper is to analyze the relationship between the heliostat field range and the receiver depression angle to obtain the optimal plant design proposal. Considering receivers with different shape apertures, heliostat field ranges were preliminarily determined by calculation based on the geometrical optics theory. Moreover, receiver depression angle, the most important parameter in field range determination, was deduced by a simplified formula with the only independent variable of latitude. Then, the rationality of this formula was demonstrated by comparing the heliostat field data calculated with different receiver depression angles based on the case study. From the simulation results, the layout scheme of heliostat field is relatively optimal when the value of the receiver depression angle is determined according to the formula developed in this paper. Also, once the value of the receiver depression angle was chosen in some reasonable range around the optimal value, the installed capacity of plant is mainly dependent on the tower height, the receiver aperture area, the heliostat dimension and the heliostat placement. The above-drawn conclusions indicate that the formula deduced in this paper may greatly simplify the design work of the heliostat field layout.