Cascade refrigeration system with fluoroolefin refrigerant

Abstract

The present invention relates to a cascade refrigeration system which circulates a refrigerant comprising a fluoroolefin therethrough. The cascade refrigeration system includes a low temperature refrigeration loop and a medium temperature refrigeration loop. The fluoroolefin circulates through either loop, or both. In a particular embodiment, the fluoroolefin circulates through the medium temperature loop. In a particular embodiment, where the cascade refrigeration system includes a first and a second cascade heat exchanger, and a secondary heat transfer loop which extends between the first and second cascade heat exchangers, either the first and / or second refrigerant may be, but need not necessarily be, a fluoroolefin.

Description

BACKGROUND[0001]1. Field of the Disclosure[0002]The present disclosure relates to a cascade refrigeration system which circulates a refrigerant comprising a fluoroolefin therethrough. In particular, such a cascade system includes a medium temperature loop and a low temperature loop, and a fluoroolefin refrigerant may be used in either loop, or both.[0003]2. Description of Related Art[0004]Cascade refrigeration systems are known in the art, see for example, ICR07-B2-358, “CO2-DX Systems for Medium-and Low-Temperature Refrigeration in Supermarket Applications”, T. Sienel, O. Finckh, International Congress of Refrigeration, 2007, Beijing. Such a system typically uses a refrigerant such as 1,1,1,2-tetrafluoroethane (R134a) or blends thereof with HFC-125 and HFC-143a (i.e., R404A) in the medium temperature loop and carbon dioxide (CO2) in the low temperature loop to provide cooling to display cases, for instance, in supermarkets.[0005]The refrigeration industry has been working for the p...

AI Technical Summary

Benefits of technology

[0008]The object of the present disclosure is to provide cascade refrigeration systems which use refrigerant compositions which have unique characteristics to meet the demands of low or zero ozone depletion potential and lower global warming potential as compared to current refrigerants.

[0009]In addition to lower global warming potential advantages, the cascade refrigeration systems of the present invention may have higher energy efficiency and capacity than currently used cascade refrigeration systems.

[0013](c) a first compressor having an inlet and an outlet, wherein the first refrigerant vapor from the evaporator circulates to the inlet of the first compressor and is compressed, thereby increasing the pressure and the temperature of the first refrigerant vapor, and the compressed first refrigerant vapor circulates to the outlet of the first compressor;

[0017](e) a second compressor having an inlet and an outlet, wherein the second refrigerant vapor from the cascade heat exchanger system is drawn into the compressor and is compressed, thereby increasing the pressure and temperature of the second refrigerant vapor;

[0019](g) a second expansion device which reduces the pressure and temperature of the second refrigerant liquid exiting the condenser and entering the second inlet of the cascade heat exchanger system.

Problems solved by technology

Further environmental regulations may ultimately cause global phase out of certain HFC refrigerants.

Many of these suggested replacements are toxic, flammable, and / or have low energy efficiency.

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