Abstract:
A multi-area coating optimization method of selective absorbing coating is proposed to reduce the radiation heat loss which increases exponentially at high temperatures. Based on the spatial inhomogeneous characteristics of solar heat flux around the receiver,the optimal cutoff wavelength optimization of selective coatings to different areas on the external surfaces of the receiver is conducted.Heat loss performance analysis,all-day adaptability analysis and annual performance analysis are performed in comparison with traditional gray body coatings and uniform selective absorbing coatings. The results show that on December 21,a typical day in Pagri,when the HTF inlet temperature is 290 ℃ and outlet temperature is 800 ℃,compared with the traditional gray body coating receiver and the uniform selective coating receiver,the radiation heat loss of the multi-area coating receiver can be reduced by 89.8% and 75.7%,respectively,and the total heat loss can be reduced by 63.9% and 38.5%,respectively. And the annual photothermal conversion efficiency of the multi-area coating receiver can be improved by 8.1% and 2.4%,respectively.