| 摘要: |
| 本文提出采用非共沸工质的机械过冷跨临界CO2热泵供暖系统，并建立系统热力学模型，与采用纯质的机械过冷跨临界CO2热泵系统进行对比。结果表明：在环境温度为-12 ℃、用户供回水温度为65/40 ℃条件下，采用大温度滑移非共沸工质R1234ze(E)/R601(60/40)时，系统COP高达2.45，相对采用纯质最高提升13.82%。采用非共沸工质可有效降低系统排气压力并获得较大过冷度，减小节流不可逆损失。使用R290/R601(70/30)时，最优排气压力可降低27.85%。非共沸工质的使用可有效改善过冷过程的温度匹配，使用R1234ze(E)/R601(60/40)时系统?效率相对纯质最高提升14.09%。较大的温度滑移及合理的温焓曲线凹凸性是机械过冷CO2热泵系统非共沸工质选取的两个重要原则，推荐选用R1234ze(E)/R601(60/40)。 |
| 关键词: 供暖 热泵 机械过冷 温度匹配 非共沸工质 CO2 |
| DOI： |
| 投稿时间：2021-03-06 修订日期：2021-06-09
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| 基金项目:国家自然科学基金（No. 51806151）资助项目,天津市自然科学基金项目（20JCQNJC00600）、天津市研究生科研创新项目（2020YJSS060）和大学生创新创业训练项目（202110069067）资助。 |
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| Performance of Transcritical CO2 Air-source Heat Pump Heating System with Mechanical Subcooling Using Zeotropic Refrigerant |
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| Abstract: |
| In this study, a mechanical subcooling transcritical CO2 heat pump heating system using a zeotropic refrigerant is proposed. A thermodynamic model is developed for this system and compared with that using a pure refrigerant. The results indicate that the coefficient of performance employing R1234ze(E)/R601(60/40) with a large temperature glide is up to 2.45, which is 13.82% higher than that of the pure component, at an ambient temperature of -12 ℃ and supply/return water temperatures of 65°C/40°C. The discharge pressure of the CO2 system can be efficiently reduced, and a higher subcooling degree is achieved using a zeotropic refrigerant; hence, the throttling irreversible loss decreases. The optimal discharge pressure is reduced by 27.85% using R290/R601(70/30). The temperature match in the subcooling process can be efficiently improved, and the exergy efficiency is up to 14.09% higher than that of the pure refrigerant component when using R1234ze(E)/R601(60/40). The relatively large temperature glide and suitable concave-convex characteristic of the temperature-enthalpy curve are the two key principles for zeotropic refrigerant selection used for CO2 heat pump systems with mechanical subcooling. Finally, the utilization of R1234ze(E)/R601(60/40) is recommended. |
| Key words: heating heat pump mechanical subcooling temperature matching zeotropic refrigerant CO2 |
