Abstract A novel solar power tower system that integrates with the cascade supercritical carbon dioxide Brayton-steam Rankine cycle is proposed to tackle the challenges of a simple supercritical carbon dioxide system in solar power systems. It provides a large storage capacity and can react to the fluctuation of solar radiation by adjusting the mass flow rate of molten salts in the receiver and heat exchanger. The fundamental is illustrated and comprehensive mathematical models are built. Energy and exergy analysis in the heat collection and power conversion processes is conducted. A comparison between the novel system and simple supercritical carbon dioxide system is made at a design plant output of 10 MW. Results indicated that: (1) the cascade system has a lower receiver inlet temperature, wider temperature difference across the receiver, higher specific work of the thermal energy storage system and lower mass flow rate of the working fluids. The solar-thermal conversion efficiency of the receiver is improved significantly. The heat gain of the tower receiver of the novel system is 53.4 MWh, which is about 7.1 MWh more than that of the simple system. The electricity production of the cascade system is improved by 9.5% at design point; (2) The novel system can generate constant electricity in a wide range of solar radiation and offer flexible control strategy for heat collection and storage. It is a promising option for central solar tower technology with a high efficiency, large storage capacity and short payback period.

中文翻译：

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级联超临界二氧化碳布雷顿-蒸汽朗肯循环太阳能塔系统性能研究

摘要 提出了一种与级联超临界二氧化碳布雷顿-蒸汽朗肯循环相结合的新型太阳能发电塔系统，以解决太阳能发电系统中简单的超临界二氧化碳系统的挑战。它提供了很大的存储容量，并且可以通过调节接收器和热交换器中熔盐的质量流量来对太阳辐射的波动做出反应。说明了基本原理并建立了全面的数学模型。进行热量收集和功率转换过程中的能量和火用分析。在设计工厂输出为 10 MW 的情况下，对新型系统和简单的超临界二氧化碳系统进行了比较。结果表明：（1）级联系统接收器入口温度较低，接收器两端温差较大，热能储存系统的更高比功和更低的工作流体质量流量。接收器的光热转换效率显着提高。新型系统塔式接收器的得热量为53.4 MWh，比简单系统高约7.1 MWh。梯级系统发电量在设计点提高9.5%；(2) 新型系统可以在较宽的太阳辐射范围内产生恒定的电能，并为热量收集和储存提供灵活的控制策略。它具有效率高、存储容量大、投资回收期短等特点，是一种很有前景的中央太阳能塔技术选择。接收器的光热转换效率显着提高。新型系统塔式接收器的得热量为53.4 MWh，比简单系统高约7.1 MWh。梯级系统发电量在设计点提高9.5%；(2) 新型系统可以在较宽的太阳辐射范围内产生恒定的电能，并为热量收集和储存提供灵活的控制策略。它具有效率高、存储容量大、投资回收期短等特点，是一种很有前景的中央太阳能塔技术选择。接收器的光热转换效率显着提高。新型系统塔式接收器的得热量为53.4 MWh，比简单系统高约7.1 MWh。梯级系统发电量在设计点提高9.5%；(2) 新型系统可以在较宽的太阳辐射范围内产生恒定的电能，并为热量收集和储存提供灵活的控制策略。它具有效率高、存储容量大、投资回收期短等特点，是一种很有前景的中央太阳能塔技术选择。(2) 新型系统可以在较宽的太阳辐射范围内产生恒定的电能，并为热量收集和储存提供灵活的控制策略。它具有效率高、存储容量大、投资回收期短等特点，是一种很有前景的中央太阳能塔技术选择。(2) 新型系统可以在较宽的太阳辐射范围内产生恒定的电能，并为热量收集和储存提供灵活的控制策略。它具有效率高、存储容量大、投资回收期短等特点，是一种很有前景的中央太阳能塔技术选择。