The Optimizing Design Of High Temperature Solar Thermal Receiver

The solar thermal receiver is the most important parts in the solar thermal electricity generation, which takes charge of the conversion of solar radiation to fluid heat energy, which will affect the system temperature and the efficiency. The solar thermal receiver was analyzed and summarized in this paper, so as to get the parameters which affect the receiver performance. The straight tube receiver and helix tube receiver were simulated by numerical method, it was found that two of the receivers could reach 900K, efficiency was about 52%. The cavity receiver had some advantageous characteristics, such as supplying hot gas at exit temperature of up to 1500K and the 80% efficiency, which was very suitable for a high temperature thermal application.In view of the difficulty in machining, setting and high flow resistance of the porcupine structure, in this paper the layer high-temperature ceramic bubbles was substituted for porcupine structure, which was simpler in installing, examining, repairing, clearing and fixing. This structure could make an effective convection heat transfer with strong three-dimensional flow mixing. In addition, the structure still could enhance surface coarseness and spread over a large heat transfer area. The results indicated that the heat transfer of receiver with high-temperature ceramic bubbles layer was better than that with the porcupine structure, its efficiency was about 81.8%. The porosity had great effect on the wall temperature, exit gas temperature and electricity, the porosity 0.75 was good enough by simulating.The insulating layer material, vacuum cavity and the coating were introduced in order to solve the heat loss of the high temperature receiver. The foil coating for vacuum inside wall and the silicon coating for the vacuum outside wall were chosen for increasing the absorber coefficients and reducing heat loss. It was useful by adding the vacuum cavity to reduce the wall temperature. The system efficiency of numerical simulation could be enhanced 1%. Moreover, the variety of inlet diameter, L/D, cavity diameter, length, lean angle were simulated for optimizing the receiver.