Heatcraft Refrigeration Products LLC

Hill Phoenix, Inc.

Other

Lennox Industries Inc.

Shitong Zha

Xi Sun

Augusto Zimmermann

David K Hinde

Douglas Cole

Fardis Najafifard

Michael Hollister

John D Bittner

J Scott Martin

Lin Lan

Nicole Z Martin

Mike Hollister

Joe T Wilkerson, Jr

John M Gallaher

Robert B Uselton

Jeffrey E Newel

Masood Ali

Robert B “Dutch” Uselton

Joseph R Poland

Janakiraman Kuppuswamy

Timothy E Lukes

Willis L McCullough

Sun Xi

A refrigeration system includes a low side heat exchanger configured to receive a first portion of a working fluid from a flash tank. The refrigeration system further includes a header positioned downstream of the low side heat exchanger, wherein the header has one or more inlets configured to receive the working fluid from the low side heat exchanger, a first outlet, and a second outlet. The refrigeration system further includes a check valve positioned downstream of the first outlet, a compressor positioned downstream of the check valve, and an oil drain conduit. The oil drain conduit has an inlet in fluid communication with the second outlet of the header. The drain conduit has an outlet configured to discharge at least a portion of the working fluid to a position downstream of the check valve and upstream of the compressor.

Refrigeration system with an oil drain conduit and methods of use

The disclosure provides a method of operating a refrigeration system. The method includes operating a first low-temperature evaporator in a refrigeration mode, where the first low-temperature evaporator receives refrigerant from a flash tank. The method includes operating a second low-temperature evaporator in a refrigeration mode, where the first low-temperature evaporator receives refrigerant from the flash tank. The method includes causing the first low-temperature evaporator to operate in the defrost mode by: closing a first controllable valve in a refrigerant conduit that couples the first low-temperature evaporator to a low-temperature compressor of the refrigeration system, and directing the refrigerant exiting the first low-temperature evaporator to be received by the second low-temperature evaporator.

Refrigeration system and method of defrosting the same

A refrigeration system includes evaporators, one or more medium temperature compressors, and a three-way valve positioned downstream from the one or more medium temperature compressors. The three-way valve receives the compressed refrigerant from the medium temperature compressors and directs flow of the received compressed refrigerant to (i) a gas cooler and/or (ii) one or more of the evaporators based on an operation mode of the evaporators. A controller determines that operation of a first evaporator in a defrost mode is indicated and causes the first evaporator to operate in the defrost mode by adjusting the three-way valve to direct a portion of the received compressed refrigerant to the first evaporator.

Hot gas defrost using medium temperature discharge gas

An apparatus includes a high side heat exchanger, a flash tank, a load, a compressor, and a heat exchanger. The high side heat exchanger removes heat from a refrigerant. The flash tank stores the refrigerant from the high side heat exchanger and to discharge a flash gas. The load uses the refrigerant from the cool a space proximate the load. The compressor compresses the refrigerant from the load. The heat exchanger transfers heat from the refrigerant from the compressor to the flash gas before the refrigerant from the compressor reaches the high side heat exchanger. The heat exchanger directs the flash gas to the compressor after heat from the refrigerant from the compressor is transferred to the flash gas and directs the refrigerant from the compressor to the high side heat exchanger after heat from the refrigerant from the compressor is transferred to the flash gas.

Cooling system

A cooling system drains oil from low side heat exchangers to vessels and then uses compressed refrigerant to push the oil in the vessels back towards a compressor. Generally, the cooling system operates in three different modes of operation: a normal mode, an oil drain mode, and an oil return mode. During the normal mode, a primary refrigerant is cycled to cool one or more secondary refrigerants. As the primary refrigerant is cycled, oil from a compressor may mix with the primary refrigerant and become stuck in a low side heat exchanger. During the oil drain mode, the oil in the low side heat exchanger is allowed to drain into a vessel. During the oil return mode, compressed refrigerant is directed to the vessel to push the oil in the vessel back towards a compressor.

Cooling system with oil return to accumulator

A cooling system partially floods the low temperature low side heat exchangers (e.g., freezers) in the system. An accumulator is positioned between the low temperature low side heat exchangers and the low temperature compressor. The accumulator collects the refrigerant (both liquid and vapor) from the flooded low temperature low side heat exchangers. Refrigerant discharged by the low temperature compressor is fed through the accumulator so that heat can be transferred to the refrigerant collected in the accumulator. As a result, the temperature of the refrigerant discharged by the low temperature compressor drops before that refrigerant reaches the medium temperature compressor.

Cooling system with flooded low side heat exchangers

A refrigeration system includes pressure-regulating valve positioned between two flash tanks and a heat exchanger is positioned downstream from a medium temperature compressor. After determining that operation of an evaporator in a defrost mode is indicated, the system causes the evaporator to operate in the defrost mode by adjusting the pressure-regulating valve to increase a pressure of a first flash tank relative to a pressure of a second flash tank, allowing flow of refrigerant from the first flash tank to the heat exchanger, and allowing refrigerant heated by the heat exchanger to flow to the first evaporator.

Hot gas defrost using fluid from high pressure tank

A cooling system drains oil from low side heat exchangers to vessels and then uses compressed refrigerant to push the oil in the vessels back towards a compressor. Generally, the cooling system can operate in any number and combination of three different modes of operation: a normal mode, an oil drain mode, and an oil return mode. During the normal mode, a primary refrigerant is cycled to cool one or more secondary refrigerants. As the primary refrigerant is cycled, oil from a compressor may mix with the primary refrigerant and become stuck in a low side heat exchanger. During the oil drain mode, the oil in the low side heat exchanger is allowed to drain into a vessel. During the oil return mode, compressed refrigerant is directed to the vessel to push the oil in the vessel back towards a compressor.

A cooling system drains oil from low side heat exchangers to vessels and then uses compressed refrigerant to push the oil in the vessels back towards a compressor. Generally, the cooling system operates any number and combination of three different modes of operation: a normal mode, an oil drain mode, and an oil return mode. During the normal mode, a primary refrigerant is cycled to cool one or more secondary refrigerants. As the primary refrigerant is cycled, oil from a compressor may mix with the primary refrigerant and become stuck in a low side heat exchanger. During the oil drain mode, the oil in the low side heat exchanger is allowed to drain into a vessel. During the oil return mode, compressed refrigerant is directed to the vessel to push the oil in the vessel back towards a compressor.

Cooling system with oil return to oil reservoir

A refrigeration system includes a controllable valve positioned downstream from one or more low-temperature compressors. The controllable valve receives compressed refrigerant from the low-temperature compressors and directs flow of the refrigerant to one or both of (i) medium-temperature compressors downstream from the controllable valve and (ii) one or more evaporators based on an operation mode of the evaporators. A pressure-regulating valve is disposed in refrigerant conduit coupling a first flash tank to a second flash tank. After determining to operate a first evaporator in a defrost mode, a controller adjusts the controllable valve to direct a portion of refrigerant to the first evaporator and adjusts the pressure-regulating valve to increase a pressure of the first flash tank relative to that of the second flash tank.

Hot gas defrost using low temperature compressor discharge gas and auxiliary flash tank

An apparatus includes a high side heat exchanger, a heat exchanger, a flash tank, a first expansion valve, a second expansion valve, a load, a first compressor, and a second compressor. During a first mode of operation, the second expansion valve directs refrigerant from the flash tank to the load. The refrigerant from the load bypasses the first compressor. The heat exchanger transfers heat from the refrigerant from the high side heat exchanger to the refrigerant from the load. The second compressor compresses the refrigerant from the heat exchanger. During a second mode of operation, the first expansion valve directs refrigerant from the flash tank to the load. The first compressor compresses the refrigerant from the load and the second compressor compresses the refrigerant from the first compressor before the refrigerant from the first compressor reaches the high side heat exchanger.

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Snellville, GA, United States of America

Shitong Zha