Transcritical refrigerant vapor compression system with charge management

Abstract

A refrigerant vapor compression system includes a refrigerant-to-refrigerant heat exchanger economizer and a flash tank disposed in series refrigerant flow relationship in the refrigerant circuit intermediate a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger. A primary expansion valve is interdisposed in the refrigerant circuit upstream of the refrigerant heat absorption heat exchanger and a secondary expansion valve is interdisposed in the refrigerant circuit upstream of the flash tank. The flash tank functions as a refrigerant charge storage reservoir wherein refrigerant expanded from a supercritical pressure to subcritical pressure separates into liquid and vapor phases. A refrigerant vapor bypass line is provided to return refrigerant vapor from the flash tank to the refrigerant circuit downstream of the refrigerant heat absorption heat exchanger. The primary expansion valve and a flow control valve interdisposed in the refrigerant vapor bypass provide refrigerant charge management.

Description

FIELD OF THE INVENTION [0001]This invention relates generally to refrigerant vapor compression systems and, more particularly, to refrigerant charge management in a refrigerant vapor compression system operating in a transcritical cycle.BACKGROUND OF THE INVENTION[0002]Refrigerant vapor compression systems are well known in the art and commonly used for conditioning air to be supplied to a climate controlled comfort zone within a residence, office building, hospital, school, restaurant or other facility. Refrigerant vapor compression systems are also commonly used in refrigerating air supplied to display cases, merchandisers, freezer cabinets, cold rooms or other perishable / frozen product storage area in commercial establishments.[0003]Refrigerant vapor compression systems are also commonly used in transport refrigeration systems for refrigerating air supplied to a temperature controlled cargo space of a truck, trailer, container or the like for transporting perishable / frozen items ...

AI Technical Summary

Benefits of technology

[0008]A transcritical refrigerant vapor compression system having improved refrigerant charge management includes a compression device, a refrigerant heat rejection heat exchanger, a refrigerant heat absorption heat exchanger, and a refrigerant-to-refrigerant heat exchanger economizer and a flash tank disposed in a primary refrigerant circuit in series refrigerant flow relationship intermediate a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger. A primary expansion valve interdisposed in the refrigerant circuit in operative association with and upstream of the refrigerant heat absorption heat exchanger and a secondary expansion valve interdisposed in the refrigerant circuit in operative association and upstream of the flash tank. A refrigerant vapor bypass line establishes refrigerant vapor flow communication between the flash tank and a suction pressure portion of the primary refrigerant circuit downstream of the refrigerant heat absorption heat exchanger. A bypass flow control valve having an open position and a closed position is interdisposed in the refrigerant vapor bypass line for controlling the flow of refrigerant vapor through the refrigerant vapor bypass line.

Problems solved by technology

Additionally, transport refrigerant vapor compression systems are subject to vibration and movements not experienced by stationary refrigerant vapor compression systems.

Thus, the use of a conventional refrigerant accumulator in the suction line upstream of the compressor suction inlet to store excess refrigerant liquid would be subject to sloshing during movement that could result in refrigerant liquid being undesirably carried through the suction line into the compressor via the suction inlet thereto.

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