塔式外置式吸热器多区域涂层优化与性能分析

为减少塔式太阳能吸热器在高温下快速增加的辐射热损,基于聚光太阳辐射的空间分布不均匀特性,提出并优化一种在吸热器表面不同入射能流区域采用不同光谱选择性吸收涂层的多区域涂层设计方法,并与均一选择性吸收涂层和传统灰体涂层吸热器进行热损性能、全天适应性和全年性能的对比分析。结果表明：在中国帕里地区,吸热器进口温度为290 ℃、出口温度为800 ℃的条件下,多区域涂层对比传统灰体涂层和均一选择性吸收涂层吸热器在典型日12月21日中的辐射热损分别降低89.8%和75.7%,总热损分别降低63.9%和38.5%;全年光热转换效率可分别提升8.1%和2.4%。

MULTI-AREA COATING OPTIMIZATION AND PERFORMANCE ANALYSIS OF SOLAR TOWER EXTERNAL RECEIVER

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.