The solar power tower (SPT) is regarded as the most promising technology used for the next-generation concentrated solar-thermal power (CSP) plant. However, the degraded solar-thermal conversion performance of the solar tower receiver in the SPT system significantly reduces its power generation efficiency and capacity. In the previous study carried out by the authors, an unperceived negative thermal-flux phenomenon was discovered in the tower receiver, which is one of the main reasons for the degradation of the tower receiverâ€™s thermal performance. Aiming to eliminate the negative thermal-flux phenomenon, this study proposes a novel optimization method by depositing the unique solar selective-absorbing coatings on the negative thermal-flux regions to improve the solar-thermal conversion performance of these regions. Four kinds of solar selective-absorbing coatings (SSCs) with different spectral selectivities, namely, silver coating, black chrome coating, and ideal coatings with cutoff wavelengths of 2.5 Î¼m and 1.5 Î¼m, are employed to investigate the effects on the heat transfer characteristics of the negative thermal-flux region and overall thermal performance of the tower receiver. Besides, the economic metrics of the above four kinds of novel tower receivers with different solar selective coatings are also evaluated in this study. The results show that the optimization method by SSC substitution at negative thermal-flux regions exerts an excellent role in eliminating the adverse effects of the negative thermal-flux region. The efficiency of the novel tower receiver with an ideal coating could be significantly improved by 12.03 %. In addition, the annual power output of an SPT plant with the novel receiver is effectively improved by 5.0 %, and the levelized cost of energy is reduced by 4.9 %.
Keywords Solar energy, Concentrated solar power, solar selective coating, tower receiver, techno-economic