International Journal of Air-Conditioning and Refrigeration

The Society of Air-Conditioning and Refrigerating Engineers of Korea (대한설비공학회)
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The Control of Superheat and Capacity for a Variable Speed Refrigeration System Based on PI Control Logic

  • Hua, Li (Department of Refrigeration and Air-conditioning Engineering, Graduate School, Pukyong National University) ;
  • Jeong, Seok-Kwon (School of Mechanical Engineering, Pukyong National University)
  • Published : 2007.06.30
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Abstract

In this paper, we suggest the high efficient control method based on general PI control law for a variable speed refrigeration system. In the variable speed refrigeration system, the capacity and the superheat are mainly controlled by an inverter and an electronic expansion valve, respectively, for saving energy and improving coefficient of performance. Thus, we proposed a decoupling model to eliminate the interfering loop between the capacity and superheat at first. Next, we designed PI controller to control the capacity and superheat independently and simultaneously. Finally, the control performance was investigated through some experiments. The experimental results showed that the proposed PI controller based on the decoupling model can obtain good control performance under the various control references and thermal load.

Keywords

References

  1. Koury, R. N. N., Machado, L., and Ismail, K. A. R., 2001, Numerical simulation of a variable speed refrigeration system, Int. J. Refrig. Vol. 24, pp.192-200 https://doi.org/10.1016/S0140-7007(00)00014-1
  2. Willatzen, M., Pettit, N. B. O. L., and Ploug Sorensen, L., 1998, A general dynamic simulation model for evaporators and condensers in refrigeration, Part I : moving-boundary formulation of two-phase flows with heat exchange, Int. J. Refrig., Vol. 21, No. 5, pp. 398-403 https://doi.org/10.1016/S0140-7007(97)00091-1
  3. Willatzen, M., Pettit, N. B. O. L., and Ploug Sorensen, L., 1998, A general dynamic simulation model for evaporators and condensers in refrigeration, Part II : simulation and control of an evaporator, Int. J. Refrig., Vol. 21, No. 5, pp, 404-414 https://doi.org/10.1016/S0140-7007(97)00092-3
  4. Choi, J. M., Kim, Y. C., and Ha, J. H., 2001, Experimental study on superheat control of a variable speed heat pump, SAREK, Vol. 13, No. 4, pp. 233-241(in Korean)
  5. Outtagarts, A., Haberschill, P., and Lallemand, M., 1997, The transient response of an evaporator fed through an electronic expansion valve, International Journal of Energy Research, Vol. 21, pp.793-807 https://doi.org/10.1002/(SICI)1099-114X(199707)21:9<793::AID-ER297>3.0.CO;2-P
  6. Yoon, S. H. and Chang, H. W., 2001, Empirical modeling and control performance simulation of an inverter heat pump system, Proceedings of the SAREK, pp.725-730(in Korean)
  7. Hua, L. and Jeong, S. K, 2006, An experimental model for decoupling control of a variable speed refrigeration system, KSPSE, Vol. 10, No.3, pp.81-87(in Korean)
  8. Hua, L., Jeong, S. K, and Yoon, J I., 2006, Decoupling control desing for variable speed refrigeration system of a ship, Journal of the Korean Society of Marine Engineering, Vol. 30, No.7, pp.808-815
  9. Hua, Li, Lee, D. W., and Jeong, S. K, 2006, The superheat and capacity control of a variable speed refrigeration system with PI control logic, Proceedings of the SAREK, pp. 21-26(in Korean)