This paper investigates the thermal performance of the recompression supercritical carbon dioxide power cycle integrated with a direct air-cooled heat exchanger. The desirable attributes for economical concentrated solar power plants are their integration ability with thermal energy storage and to accommodate dry cooling. The expressively influencing parameters such as compressor inlet temperature, pressure, and split mass fraction have been investigated for cycle maximum efficiency under arid climatic conditions. The cooling process of supercritical carbon dioxide, unlike steam condensation, is sensible heat transfer with the non-linear variation of thermophysical properties. Effective, efficient, and affordable heat exchanger technology is crucial for the deployment of supercritical carbon dioxide Brayton power cycles in concentrated solar power plants. A MATLAB code has been developed for an air-cooled heat exchanger with multi-pass sub heat exchanger approach to overcome the inevitable temperature variations at the extreme end of the gas cooler. A two dimensional discretization methodology is used to model the heat exchanger to accommodate the rapidly varying isobaric heat capacity in the critical temperature region. The heat transfer and pressure drop performance are calculated using empirical correlations for the Nusselt number and friction factor for each sub-heat exchanger. With the increased contact time of cooling and process fluid, the desired gas cooler outlet temperature of 33.5 °C is achieved by rejecting 823.76 kW, 359.5 kW, and 219.46 kW amount of heat from each sub-heat exchanger, respectively. The results of this work are of significance for the design of the air-cooled heat exchanger for the supercritical carbon dioxide power generation system.

本文研究了与直接风冷热交换器集成的再压缩超临界二氧化碳功率循环的热性能。经济的集中式太阳能发电厂的理想属性是它们与热能存储的集成能力以及适应干冷的能力。为了研究在干旱气候条件下的循环最大效率，已经研究了具有影响力的参数，例如压缩机入口温度，压力和分流质量分数。与蒸汽冷凝不同，超临界二氧化碳的冷却过程是显着的热传递，具有热物理性质的非线性变化。有效，高效，廉价的热交换器技术对于在集中式太阳能发电厂中部署超临界二氧化碳布雷顿功率循环至关重要。已经为具有多程子热交换器方法的风冷热交换器开发了MATLAB代码，以克服气体冷却器极端温度下不可避免的温度变化。使用二维离散化方法对热交换器进行建模，以适应临界温度区域中快速变化的等压热容量。使用每个子热交换器的努塞尔数和摩擦系数的经验相关性来计算传热和压降性能。随着冷却液和过程流体接触时间的增加，通过剔除823.76 kW，359.5 kW，每个子热交换器的热量分别为219.46 kW和。这项工作的结果对于超临界二氧化碳发电系统的风冷热交换器的设计具有重要意义。