Experimental evaluation of freezing processes in horizontal plate freezers using CO2 as refrigerant

Abstract This paper deals with an experimental analysis of freezing processes using a horizontal plate freezer with CO 2 as refrigerant. The CO 2 is supplied from an experimental CO 2 /NH 3 cascade refrigeration system facility with a 9 kW of refrigeration capacity at −50 °C. The experimental facility, the data acquisition system and the experimental methodology are described. The experimental results include the temperature evolution in the product to be frozen, the CO 2 evaporating temperature and freezing times. Results show a clear link between the freezing time and CO 2 average evaporating temperature. The observed trend showed that a temperature reduction of 1 °C causes a reduction of approximately 2 min in the freezing time. The experimental results also include the refrigeration capacity of the facility, the electric power of the compressors and the cascade system COP. In addition, a numerical model of the freezing process using a commercial software was developed and validated. The results obtained would confirm that the use of CO 2 as refrigerant in plate freezers represents a viable alternative to the refrigerants currently in use.

[1]  G. Lorentzen.  Revival of carbon dioxide as a refrigerant , 1994 .

[2]  Björn Palm,et al.  Ammonia in low capacity refrigeration and heat pump systems , 2008 .

[3]  John R. Thome,et al.  State-of-the-art of two-phase flow and flow boiling heat transfer and pressure drop of CO2 in macro- and micro-channels. , 2005 .

[4]  Tao Yang,et al.  An improvement to the simulation of phase-change heat-transfer during soil freezing and thawing , 2009 .

[5]  Luisa F. Cabeza,et al.  Review on thermal energy storage with phase change: materials, heat transfer analysis and applications , 2003 .

[6]  Clark W. Bullard,et al.  Experimental results of transcritical CO2 heat pump for residential application , 2003 .

[7]  S. Fukusako,et al.  Recent advances in research on water-freezing and ice-melting problems , 1993 .

[8]  Clark W. Bullard,et al.  Development of a microchannel evaporator model for a CO2 air-conditioning system , 2001 .

[9]  Y. B. Tao,et al.  Experimental study on the performance of CO2 residential air-conditioning system with an internal heat exchanger , 2010 .

[10]  José Fernández-Seara,et al.  Experimental evaluation of a cascade refrigeration system prototype with CO2 and NH3 for freezing process applications , 2011 .

[11]  Petter Nekså,et al.  Commercial refrigeration system using CO2 as the refrigerant , 2004 .

[12]  Andy Pearson.  New developments in industrial refrigeration , 2001 .

[13]  Eckehard Specht,et al.  Computational aspects of temperature-based finite element technique for the phase-change heat conduction problem , 2009 .

[14]  Andy Pearson,et al.  ICR0021 CARBON DIOXIDE - NEW USES FOR AN OLD REFRIGERANT , 2005 .