US 5,839,294 AGranted

Chiller with hybrid falling film evaporator

AssigneeCarrier Corporation

InventorsRobert H. L. Chiang, Jack L. Esformes, Edward A. Huenniger

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Abstract

A vapor compression refrigeration system for cooling a liquid in which there is a spray dispenser for distributing liquid refrigerant over the tubes in a shell-and-tube type evaporator. The differential pressure in the refrigerant flow loop across the evaporator is the sole means of producing a flow through the spray dispenser. The evaporator is operated as a hybrid falling film heat exchanger, that is, in a semi-flooded condition. The lower portion of the evaporator shell is flooded with liquid refrigerant to wet the lower tubes in the tube bundle while the tubes in the upper portion are wetted only by refrigerant spray from the spray dispenser. The system is operated in a steady state condition whereby at least twenty-five percent (25%) of the tubes in the evaporator operate in a flooded heat transfer mode. The system allows a reduction in the amount of refrigerant charge in the system while at the same time avoiding the use of a recirculating system and pump.

Claims17

Dependent claims

A vapor compression refrigeration system for cooling a liquid including a compressor, a condenser, an expansion device, and an evaporator, all of which are connected together in series to form a closed refrigerant flow loop for circulating a refrigerant therethrough, said evaporator comprising:

an outer shell having an upper end and a lower end, said shell having one refrigerant inlet and one refrigerant outlet therein;
a plurality of substantially horizontal heat transfer tubes contained within said outer shell, at least a portion of said tubes being adjacent the upper end of said shell and at least a portion of said tubes being adjacent the lower end of said shell, said tubes being adapted to have a liquid to be cooled flowed therethrough;
and
means for receiving refrigerant passing to said outer shell through said refrigerant inlet and for dispensing refrigerant onto said heat transfer tubes located adjacent said upper end of said outer shell;
and wherein said closed refrigerant flow loop is configured so that the level of liquid refrigerant within said outer shell is maintained at a level such that more than twenty-five percent (25%) of said horizontal tubes are immersed in liquid refrigerant during steady state operation of said refrigeration system.

2 more elements

Dependencies are inferred from the claim text.