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A study of high efficiency CO2 refrigerant VRF air conditioning system adopting multi-stage compression cycle.

Number: pap. 2138

Author(s) : OKAMOTO T., FURUSHO K., IWATA I., et al.

Summary

CO2 refrigerant is expected to be used for air conditioners due to its environmental property of GWP = 1, nonflammability and low toxicity and has already been applied to hot water supply system, refrigerators and freezers. However, since theoretical cycle COP of CO2 is poorer than that of conventional HFC in applying to air conditioners, it cannot be expected to improve the performance significantly by improving the efficiency of components adopted in the conventional single-stage CO2 cycle. Therefore, it is important to consider efficient refrigerant cycle, especially in the performance of cooling which is a weak point of CO2. Challenges also lie in reducing weight of components such as compressor and heat exchangers which have relatively heavy weight to resist high pressure and to achieve high efficiency in the system. In this study, a prototype of CO2 refrigerant VRF air conditioning system is constructed and evaluated the performance. The system is adopting the four-stage compression cycle applying a new type compressor and heat exchangers and so on aimed for high efficiency cycle and reducing weight. As a result of the evaluation, it is confirmed that CO2 cycle performance can be improved in similar extent to that of HFC refrigerant cycle. On the other hand, this high efficiency cycle consists of a lot of components and becomes more complex than HFC refrigerant cycle; therefore the size and weight of outdoor unit increases to settle these components. Further technical development will be necessary to overcome these weaknesses.

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Pages: 10 p.

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Details

  • Original title: A study of high efficiency CO2 refrigerant VRF air conditioning system adopting multi-stage compression cycle.
  • Record ID : 30019011
  • Languages: English
  • Source: 2016 Purdue Conferences. 16th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Publication date: 2016/07/11

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