Research Progress of Small-scale CO2 Two-phase Expanders
With the increased awareness in the international community, the problems of ozone depletion and greenhouse effect have received extensive attention, more and more scholars are focusing on environmental-friendly refrigerants. CO2 demonstrated its value in terms of simplicity, availability, safety, r...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Journal of Refrigeration Magazines Agency Co., Ltd.
2023-01-01
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| Series: | Zhileng xuebao |
| Subjects: | |
| Online Access: | http://www.zhilengxuebao.com/thesisDetails#10.3969/j.issn.0253-4339.2023.01.024 |
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| Summary: | With the increased awareness in the international community, the problems of ozone depletion and greenhouse effect have received extensive attention, more and more scholars are focusing on environmental-friendly refrigerants. CO2 demonstrated its value in terms of simplicity, availability, safety, reliability, and good heat transfer performance. This paper analyzes and summarizes the research progress of small-scale CO2 gas-liquid two-phase expanders. It is found that replacing the throttle valve with a CO2 expander in the cycle can effectively improve refrigeration efficiency. The cooling and heating efficiency of the cycle is 6.9% and 4.6% higher than that of the R134a cycle, and 25.76% and 16.17% higher than that of the cycle with a throttle valve, respectively. The higher the isentropic efficiency of the CO2 expander, the greater the system efficiency. As long as the isentropic efficiency of the expander is greater than 32%, the performance of the system with a CO2 expander is better than that with a regenerator. Different CO2 expanders have different efficiency, leakage, and friction loss due to their different structures. Piston type, rotor type, and other expanders have simple structures, while their leakage loss is relatively large. The efficiency of the sliding vane type, rotary vane type, and scroll type expander has been greatly improved, but their structure is more complicated, leading to more complicated manufacturing and increased production costs. The compression work is supplied to the compressor, increasing the flow rate during the expansion process, which requires designing a CO2 expander with an adjustable expansion ratio. At present, the research of CO2 expanders is basically concentrated in the laboratory, and this technology has not been commercialized yet. Therefore, the future development direction should combine experiments and theory to further study the efficiency improvement of CO2 expanders and the development of key components technology. |
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| ISSN: | 0253-4339 |