Korean Journal of Air-Conditioning and Refrigeration Engineering (설비공학논문집)

The Society of Air-Conditioning and Refrigerating Engineers of Korea (대한설비공학회)
권호 표지

Solubility Consideration in Performance Analysis of a $CO_2$ Twin Rotary Compressor

오일 용해도를 고려한 $CO_2$ 트윈 로타리 압축기 성능해석

  • Kim, Woo-Young (Department of Mechanical Engineering, Graduate School of Incheon University) ;
  • Ahn, Jong-Min (Department of Mechanical Engineering, Graduate School of Incheon University) ;
  • Kim, Hyun-Jin (Department of Mechanical Engineering, University of Incheon) ;
  • Cho, Sung-Oug (Digital Appliance Network Business, Samsung Electronics Co.)
  • Published : 2007.12.10
Download PDF
⟨ Previous Next ⟩

Abstract

For a $CO_2$ two-stage twin rotary compressor used for heat pump water heater system, changes of $CO_2$ solubility in PAG oil were investigated along the gas passages from the first stage suction to final discharge. Only slight changes in solubility took place in suction chambers for both of the first and second stages, but for compression chambers, solubility variation ranged from 0.115 to 0.136, and from 0.133 to 0.182, respectively for the first and second stages. Calculation of gas flashing in parts of leakage oil flows and of oil contained in control volumes due to solubility changes was conducted and included in gas pressure calculation. For the second stage, gas flashing amounts to around $5%\sim6%$ for most leakage flows. Cooling capacity, compressor input, and COP obtained by calculation were well compared to the experimental results. Effects of operation speed on the compressor performance was also studied: as the shaft speed increased, adiabatic efficiency decreased rapidly due to increased over-compression loss.

Keywords

References

  1. Pearson, A. B., 2003, Carbon dioxide - new uses of an old refrigerant, International Congress of Refrigeration, ICR0021
  2. Lorentzen, G., 1994, The use of natural refrigerant : a complete solution to the CFC/HCFC replacement, International Journal of Refrigeration, Vol. 18, No.3, pp. 190-197 https://doi.org/10.1016/0140-7007(94)00001-E
  3. Seeton, C., Fahl, J. and Henderson, D., 2000, Solubility, viscosity boundary lubrication and miscibility of $CO_2$ and synthetic lubricants, Preliminary Proceedings of the 4th IIR Gustav Lorentzen Conference on Natural Working Fluids, Purdue, pp.417-424
  4. Kim, H. J., An, K. J., Ahn, J. M. and Cho, S.O., 2004, Performance comparison of various types of $CO_2$ compressors for heat pump water heater application, Proceedings of 6th IIR Gustav Lorentzen Natural Working Fluids Conference, 6/A/12.00, Glasgow, UK
  5. Lee, C. 2005, An experimental study on vapor-liquid equilibrium of $CO_2$ and oil mixtures in the range of compressor working pressure, Master Thesis, Kookmin University
  6. Kim, W. Y., Ahn, J. M., Kim, H.J. and Cho, S. O., 2007, Performance analysis of a C02 two-stage twin rotary compressor, Korean Journal of Air-Conditioning and Refrigeration Engineering, Vol. 19, No.1, pp. 19-27
  7. Lee, Y.J., 2006, Workshop on $CO_2$ Heating & A/C System