International Journal of Frontiers in Engineering Technology, 2023, 5(12); doi: 10.25236/IJFET.2023.051208.
Kai Kang1, Yixin Li2
1School of Mechanical and Equipment Engineering, Hebei University of Engineering, Hebei, Handan, 056038, China
2School of Management Engineering and Business, Hebei University of Engineering, Hebei, Handan, 056038, China
With the development concept of green and environmental protection deeply rooted in people's hearts, the heliostat field has moved from theoretical knowledge to production practice with its high utilization of solar energy. In order to accurately calculate the optical efficiency of the heliostat field, it is necessary to construct the mirror field coordinate system[1] and the heliostat coordinate system, and determine the information of the sun's declination angle, sun's hour angle, sun's altitude angle, and sun's azimuth angle. Based on these angles, the direction vector of incoming and outgoing rays and the direction vector of reflected rays are calculated, and the cosine loss model is used to solve the cosine loss efficiency. When calculating shadow occlusion loss, a theoretical model of shadow occlusion efficiency was established. Coordinate transformation was used to determine whether the light in heliostat A can enter heliostat B. The occlusion efficiency of heliostat was determined by the ratio of the shadow area formed by the light entering B to the area of heliostat B. At the same time, the average optical efficiency of the heliostat field is obtained by combining the optical efficiency formula, and on this basis, the average output thermal power per unit area of the heliostat field is obtained. Through the above analysis, it was calculated that the annual average optical efficiency of a circular heliostat field which is located at 98.5 degrees east longitude, 39.4 degrees north latitude, an altitude of 3000 meters, and is a circle with a radius of 350 meters is 0.647. Its the annual average thermal output power is 36.273MW and the annual average thermal output power per unit mirror area is 0.096MW/m2. Finally, a more accurate optical efficiency calculation method was proposed, which can be used to calculate the optical efficiency of different scale heliostat fields.
Optical Efficiency, Cosine Loss, Light Blocking Efficiency Model, Optimize and Design
Kai Kang, Yixin Li. Research on optical efficiency of heliostat field based on cosine loss model and shadow light blocking efficiency model. International Journal of Frontiers in Engineering Technology (2023), Vol. 5, Issue 12: 40-49. https://doi.org/10.25236/IJFET.2023.051208.
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