Montes María José, Linares José Ignacio, Barbero Rubén, Moratilla Beatriz Yolanda
E.T.S. Ingenieros Industriales-UNED, C/Juan del Rosal 12, 28040 Madrid, Spain.
Rafael Mariño Chair in New Energy Technologies-COMILLAS-ICAI, C/Alberto Aguilera 25, 28015 Madrid, Spain.
Entropy (Basel). 2020 Aug 12;22(8):883. doi: 10.3390/e22080883.
One of the ways to make cost-competitive electricity, from concentrated solar thermal energy, is increasing the thermoelectric conversion efficiency. To achieve this objective, the most promising scheme is a molten salt central receiver, coupled to a supercritical carbon dioxide cycle. A key element to be developed in this scheme is the molten salt-to-CO heat exchanger. This paper presents a heat exchanger design that avoids the molten salt plugging and the mechanical stress due to the high pressure of the CO, while improving the heat transfer of the supercritical phase, due to its compactness with a high heat transfer area. This design is based on a honeycomb-like configuration, in which a thermal unit consists of a circular channel for the molten salt surrounded by six smaller trapezoidal ducts for the CO. Further, an optimization based on the exergy destruction minimization has been accomplished, obtained the best working conditions of this heat exchanger: a temperature approach of 50 °C between both streams and a CO pressure drop of 2.7 bar.
从聚光太阳能热能中获取具有成本竞争力电力的方法之一是提高热电转换效率。为实现这一目标，最有前景的方案是将熔盐中央接收器与超临界二氧化碳循环相结合。该方案中有待开发的一个关键部件是熔盐与二氧化碳热交换器。本文提出了一种热交换器设计，该设计避免了熔盐堵塞以及由于二氧化碳高压产生的机械应力，同时由于其紧凑的结构和高传热面积提高了超临界相的传热性能。这种设计基于蜂窝状结构，其中一个热单元由一个用于熔盐的圆形通道和围绕该通道的六个较小的用于二氧化碳的梯形管道组成。此外，基于火用损失最小化进行了优化，得出了该热交换器的最佳工作条件：两股流体之间的温度接近度为50℃，二氧化碳的压降为2.7巴。
