Modelling of a High Efficiency Refrigeration System with Heat Storage for Reverse Cycle Hot Gas Defrost

  • Ardiyansyah, Ardiyansyah (Graduate School, Chonnam National University) ;
  • Choi, Kwang-Il (Graduate School, Chonnam National University) ;
  • Oh, Jong-Taek (Dept. of Refrigeration and Air Conditioning Eng., Chonnam National University) ;
  • Oh, Hoo-Kyu (Dept. of Refrigeration and Air Conditioning Eng., Pukyong National University)
  • Published : 2007.12.30


A computer model of a high efficiency refrigeration system equipped with heat storage for reverse cycle-hot gas defrost (the stored heat is used during defrost cycle of the system) is presented. The model was developed based on both theoretical and empirical equations for the compressor, evaporator, condenser and the heat storage equipment. Simulations of the prototype system were carried out to investigate refrigeration system performance under various operating conditions during refrigeration cycles. The simulations of the evaporator during defrost cycles at 30 and $40^{\circ}C$ hot gas refrigerant temperature were also performed which resulted on shorter defrost time but only slight increase in defrost efficiency. These information on energy efficiency and the defrost time required are important in order to avoid excessive parasitic load and temperature rise of the refrigerated room.



  1. Hoffenbecker, N., Klein, S.A., Reindl, D.T., 2005, Hot Gas Defrost Model Development and Validation, Int. J. Refrig. 28: 605-615
  2. D.J. Swider, M.W. Browne, P.K. Bansal, V. Kecman, 2001. 'Modeling of Vapor- Compression Liquid Chillers with Neural Networks', App. Thermal Eng. 21: 311-329
  3. Jolly, P.G., Tso, C.P., Wong, Y.W. and Ng, A.M., 2000, Simulation and Measurement on the Full Load Performance of Refrigeration System in a Shipping Container, Int. J. Refrig. 23: 112-126
  4. Koury, R.N.N., L. Machado and K.A.R. Ismail, 2001, 'Numerical Simulation of A Variable Speed Refrigeration System', Int. J. Refrig. 24: 192-200
  5. O'Neal, D.L., Peterson K.T., Anand N.K., Schliesing J.S., 1989. 'Refrigeration System Dynamics During the reverse Cycle Defrost', ASHRAE Trans. 95: 689-698
  6. Browne, M.W., P.K. Bansal, 2002. 'Transient Simulation of Vapor-Compression Package Liquid Chillers' Int. J. Refrig. 25: 597-610
  7. Incropera, Frank. P. and David P. DeWitt 1990, Fundamental of Heat and Mass Transfer 3rd ed., Wiley and Son, Singapore
  8. Boeis A.M., K.O. Homan, J.H. Davidson, Wei Liu, 2005. 'A Variable Effectiveness Model for Indirect Thermal Storage Devices' Proc. of ASME Summer Heat Trans. Conference' HT2005-72711 Research 25: 859-880
  9. Wang, Chi-Chuan, Kuan-Yu Chi, Chun-Jung Chang, 2000, Heat Trasfer and Friction Characteristics of Plain fin-and-tube Heat Exchangers, part II: Correlation, Int. J. of Heat and Mass Trans. 43: 2693-2700
  10. Gungor, K.E., & Winterton, R.H.S., 1987, Simplified General Correlation for Saturated Flow Boiling and Comparisons of Correlations with Data, Chem. Eng. Research and Design 65: 148-156
  11. Krakow, K.I., S.Lin, L. Yan, 1992, A Model of Hot-Gas Defrosting of Evaporators, ASHRAE Trans. 98(1): 451-474
  12. Cole, R.A., 1989, Refrigeration Loads in a Freezer Due to Hot Gas Defrost and Their Associated Costs, ASHRAE Trans. 95(2): 1149-1154