Co2 Refrigeration Compressor Rack Secondary 2 Stage
CFC and HCFC, due to their influence on global warming and damage to the ozone layer, will be gradually weed out. the evaporating temperature of single freezer is currently between -30℃ and -50℃, and thus NH3 and R22 refrigeration systems are not preferable due to such unfavorable factors as negative pressure operation and liquid explosion risks. Therefore, environmental friendly refrigerant CO2 has regained its influence and popularity.
Shenzhou refrigeration has successfully developed the first CO2 refrigerating unit in China after two years’ research and with the substantial support from China Association of Refrigeration. The first CO2 refrigerating unit has already been exported to France in 2011, which proved the strengths of the promising company.
The subcritical refrigeration cycle of CO2 is same as steam compression refrigeration cycle, both the suction and discharge pressure are lower than critical pressure of CO2 and evaporating pressure and condensing pressure are lower than critical temperature. The suction and discharge of heat are under the critical conditions, heat exchange is mainly based on latent heat, and is used to low temperature stage of cascade freezer.
CO2 as low temperature stage has the following advantages:
1、Evaporating temperature of CO2 is below -50C , which has sufficient evaporating pressure. It can reach de demand of food freezing without negative pressure inside evaporator.
2、CO2 refrigerant is characterized by safety, non-toxicity and incombustibility and its molecular mass is bigger than air, so its cycle can refer to Freon refrigeration system
3、CO2 is nature working media, and it has little effect on environment.
4、Compared with other refrigerants, even under low temperature,CO2 has little viscosity and better heat transfer performance. It has larger latent heat of evaporation, large refrigerating capacity per unit of swept volume and high heat emission coefficient;