Theoretical and experimental study on the heat collection of solar dish system based on adjustable receiver

Abstract

Based on the cascade utilization of solar energy at different DNI levels, the establishment of a solar dish Stirling cogeneration system is one of the effective solutions both from the current Stirling engine technology level and from the perspective of overall system efficiency optimization. In this paper, a model of solar dish concentrating and receiving based on the position adjustable receiver is proposed, which provides a theoretical basis for the application of the solar dish system in cogeneration. The accuracy and reliability of the model are verified by the multi working condition heat collection experiment, and the change rule and value range of the key parameters in the model are determined. The results show that by adjusting the value of the excess heat removal factor in the model according to a certain rule within a certain range, the calculated results of the theoretical model can be well matched with the experimental results, and the average relative error can be controlled within 10% or even 5%. However, compared with the experimental results, the theoretical model results are more volatile, especially on a shorter time scale. In addition, with the increase of heat transfer oil temperature, the excess heat removal factor shows an increasing trend, and the overall value range is 0.45–0.95. The cases below 0.5 and above 0.9 usually occur at the beginning and end of the experiment. As the experiment goes on, when the oil temperature reaches about 80–100 ℃, the value of the excess heat removal factor begins to fluctuate, which intuitively shows that the overall trend is still subject to increase with the increase of the oil temperature, but the corresponding oil temperature range starts to overlap.