跨临界CO2循环中过冷强化技术的发展综述

近年来,由于良好的环境效益和高温出水能力,跨临界CO2循环在制冷热泵领域得到了广泛应用。但较高的回水温度会限制系统的整体性能,因此有必要进行技术改善,提升跨临界CO2循环系统性能。其中,在气体冷却器出口对工质进行过冷就是一种良好的办法。过冷的形式包含多种,如添加回热器、经济器、闪蒸罐及双系统过冷等,其中双系统又分成热电模块、辅助循环以及其他新型组合方式。研究结果表明,以上方式均可以提高跨临界循环系统性能。回热器可使系统获得10%以上的COP增量,而双系统过冷则可以达到20%以上。本文详细讨论了3种过冷方法的应用特点,为学术研究及工程应用提供了参考。

Review of the development of subcooling enhancement technology in transcritical CO_2 cycle

In recent years,due to good environmental benefits and high-temperature water output capacity,transcritical CO_2 circulation has been widely used in the field of refrigeration heat pumps.However,higher temperature of the recycled water will limit the overall performance of the system,so it is necessary to use the technology to improve the performance of the transcritical CO_2 cycle system.Among them,subcooling the working fluid at the outlet of the gas cooler is a good way.There are many types of subcooling,such as adding an internal heat exchanger,economizer,flash tank,and dual system subcooling.The dual system is divided into thermoelectric modules,auxiliary cycles,and other new combinations.The research results show that the above methods all can improve the performance of transcritical cycle systems and increase COP of the system.The internal heat exchanger can make the system obtain more than 10% COP increment,and the double system subcooling can reach more than 20%.The application characteristics of the three subcooling methods in detail was discussed,which provides a reference for academic research and engineering applications.