| 摘要: |
| 为解决常规CO2系统供暖效率低的问题，本文建立了常规CO2系统、R410A喷气增焓系统、复叠系统、间接过冷CO2系统、直接过冷CO2系统的热力学模型，对采用不同供热末端的系统性能进行优化和分析。结果表明:当供/回水温度为65 ℃/40 ℃（供热末端为暖气片）、环境温度为-20~20 ℃时，直接过冷系统的COP较常规CO2系统提升3.8%~20.9%。直接过冷系统的CO2循环占主导地位，间接过冷系统在大多数工况下辅助系统对热水生产占主导。仅需通过为直接过冷系统配置相对较小的蒸气压缩制冷循环装置，即可实现系统效率的显著提升。对于不同的CO2热泵系统，环境温度高于-15 ℃时，直接过冷系统?效率均高于其它系统，较常规CO2系统?效率提高19.3%~28.2%；环境温度低于-15 ℃时，CO2/R1234yf复叠系统的?效率最高。 |
| 关键词: 空气源热泵 CO2 复叠 间接过冷系统 直接过冷系统 喷气增焓 |
| DOI： |
| 投稿时间：2019-05-20 修订日期：2019-10-07
|
| 基金项目:国家自然科学基金(51806151)资助项目 |
|
| Performance Analysis of CO2 Air-source Heat Pump Heating System |
| Qi Haifeng,Dai Baomin,Liu Shengchun,Zhang Peng,Wang Jiahao,Qi Le |
| (Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce) |
| Abstract: |
| The energy efficiency of conventional CO2 systems used for heating is low. Therefore, cascade and subcooling systems can be adopted to improve the performance of CO2 systems. In this study, the thermodynamic models of a baseline CO2 system (BASE), R410A vapor injection system, cascade system, indirect dedicated mechanical subcooling CO2 system (IDMS), and direct dedicated mechanical subcooling CO2 system (DDMS) are established. The performances of the system with different heating terminals are optimized and analyzed. The results show that when the supply and return water temperatures are 65 ℃ and 40 ℃, respectively (the heating terminal is the traditional designed radiator) and the ambient temperature is -20–20 ℃, the COP of the DDMS system is improved by 3.8–20.9% compared with that of the baseline CO2 system. The CO2 subsystem plays a dominant role in the DDMS system. In contrast, for the IDMS system, the subcooling subsystem is more important for most cases concerning hot water production. A significant increase in system efficiency can be achieved by adding a relatively small vapor compression refrigeration cycle for the DDMS system. In the CO2 heat pump system, when the ambient temperature is above -15 ℃, the exergy efficiency of the DDMS system is higher than that of other systems. Compared to the baseline CO2 system, the exergy efficiency is improved by 19.3%–28.2%. For the cases with ambient temperature below -15 ℃, the CO2/R1234yf cascade system shows the highest exergy efficiency. |
| Key words: air-source heat pump (ASHP) CO2 cascade indirect dedicated mechanical subcooling system direct dedicated mechanical subcooling system vapor injection system |
