Liquid vapor separation in transcritical refrigerant cycle

Abstract

A refrigerant vapor compression system includes a flash tank disposed in the refrigerant circuit intermediate a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger. The flash tank has a shell defining an interior volume having an upper chamber, a lower chamber and a middle chamber. A first fluid passage establishes fluid communication between the middle chamber and the upper chamber and a second fluid passage establishing fluid communication between the middle chamber and the lower chamber. An inlet port opens to the middle chamber. A first outlet port opens to the upper chamber and a second outlet port opens to the lower chamber.

Description

FIELD OF THE INVENTION[0001]This invention relates generally to refrigerant vapor compression systems and, more particularly, to improving the separation of a two-phase refrigeration flow into a liquid portion and a vapor portion in a refrigerant vapor compression system having a flash tank economizer and operating in a transcritical cycle.BACKGROUND OF THE INVENTION[0002]Refrigerant vapor compression systems are well known in the art and commonly used in transport refrigeration systems for refrigerating air or other gaseous fluid supplied to a temperature controlled cargo space of a truck, trailer, container or the like for transporting perishable / frozen items by truck, rail, ship or intermodal. Refrigerant vapor compression systems used in connection with transport refrigeration systems are generally subject to stringent operating conditions due to the wide range of operating load conditions and the wide range of outdoor ambient conditions over which the refrigerant vapor compress...

AI Technical Summary

Problems solved by technology

Refrigerant vapor compression systems used in connection with transport refrigeration systems are generally subject to stringent operating conditions due to the wide range of operating load conditions and the wide range of outdoor ambient conditions over which the refrigerant vapor compression system must operate to maintain product within the cargo space at a desired temperature.

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

Transport refrigeration systems are also subject to size restrictions due to limitations on available space not generally associated with stationary refrigerant vapor compression systems, such as air conditioners and heat pumps.

However, because carbon dioxide has a low critical temperature and a low liquid phase density to vapor phase density ratio, most refrigerant vapor compression systems charged with carbon dioxide as the refrigerant are designed for operation in the transcritical pressure regime.

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