American Standard Inc.

American Standard International Inc.

Trane International Inc.

James W Larson

Shane A Moeykens

Jon Phillip Hartfield

Benjamin Elias Dingel

Michael Carl Boehde

James C Tischer

Harry Kenneth Ring

James C Wendschlag

A falling film evaporator includes a flow distributor for uniformly distributing a two-phase refrigerant mixture across a tube bundle. The flow distributor includes a stack of at least three perforated plates each of which are separated by nearly full-width, full-length gaps or chambers. The flow distributor may also include a suction baffle and/or a distributor baffle. The distributor baffle extends downward to provide a hairpin turn past which refrigerant travels before exiting the evaporator. This directional change helps separate liquid from a primarily gaseous refrigerant stream. The suction baffle has various size openings to ensure that the flow rate of refrigerant through the hairpin turn is generally uniform and is maintained low enough to ensure liquid disentrainment over and along the length of the tube bundle within the evaporator.

Flow distributor and baffle system for a falling film evaporator

A falling film evaporator for use in a vapor compression refrigeration chiller preferably employs a two-phase refrigerant distributor that overlies the tube bundle in the evaporator shell. The tube bundle defines at least one vapor lane which facilitates the conduct of refrigerant vapor from the interior of the tube bundle to the exterior thereof in a manner which does not substantially affect the vertically downward flow of liquid refrigerant through the tube bundle and across the vapor lane.

Falling film evaporator for a vapor compression refrigeration chiller

Efficient two-phase refrigerant mixture distribution is accomplished in a falling film evaporator by use of a refrigerant distributor disposed internal of the evaporator shell which overlies the evaporator tube bundle and which internally causes said two-phase refrigerant mixture to be made available along essentially the entire length and across essentially the entire width of the tube bundle prior to the delivery of the refrigerant out of the distributor.

Falling film evaporator having two-phase distribution system

Oil cooling is accomplished in a refrigeration chiller by flowing hot oil into heat exchange contact with liquid refrigerant which is sourced from the chiller's condenser and returned thereto. The rejection of heat from the oil to the refrigerant in an oil-cooling heat exchanger causes vaporization of the refrigerant and, in turn, creates a density difference in the refrigerant flowing from the condenser and refrigerant in and downstream of the oil-cooling heat exchanger. This density difference is responsible for inducing and maintaining refrigerant flow through the heat exchanger for oil cooling purposes.

Thermosiphonic oil cooler for refrigeration chiller

Compressor lubricant in a screw compressor-based refrigeration system is cooled by directing the lubricant from the system oil separator to an oil-cooling heat exchanger disposed in the lower portion of the system condenser where it is bathed in condensed system refrigerant. Parasitic capacity losses with respect to the compressor lubricant cooling process are thereby avoided.

Cooling of compressor lubricant in a refrigeration system

Cooling of compressor lubricant in a refrigeration system condenser

A liquid/gas bypass line bypasses an expansion device of a refrigeration apparatus. An inlet of the bypass line is connected slightly above the bottom of a condenser so that it can pass either liquid refrigerant or vaporous refrigerant, depending on the level of liquid refrigerant in the condenser. The other end of the bypass line is connected to discharge into the evaporator, bypassing the expansion device. The bypass line functions as a conventional hot gas bypass during low load conditions when the level of liquid refrigerant is below the line's inlet. When the level rises above the inlet, often occurring when the condenser coolant temperature is low and the compressor is fully loaded, the bypass line returns excess accumulated liquid refrigerant to the evaporator. Maintaining the proper levels of liquid refrigerant in both the condenser and the evaporator not only provides the most effective use of their heat transfer surfaces, but also promotes the proper return of oil to the compressor.

Liquid/gas bypass

Liquid refrigerant produced in the condenser of a refrigeration system is directed into an expansion device. The expansion device throttles the high pressure liquid refrigerant into the compressor drive motor housing of the compressor assembly within the refrigeration system. Upon entering the motor housing a first portion of the liquid refrigerant flashes into gas at a pressure intermediate compressor suction and discharge pressure. The portion of refrigerant which remains in the liquid state is directed into a jacket surrounding the stator of the compressor drive motor. As the jacket fills with liquid refrigerant, a portion of the refrigerant is directed through passages in the motor stator into contact with the motor rotor. Liquid refrigerant overflowing the jacket and flowing out the ends of the motor through the gap between the rotor and stator drains to the lowermost portion of the motor housing from where it is directed to a second expansion device. Flash gas within the drive motor housing, together with gas generated by motor cooling, is directed out of the motor housing and into the compression chamber of the compressor assembly in order to increase the capacity and efficiency of the refrigeration system.

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La Crosse, WI, United States of America

James W Larson