Pressure spike reduction for refrigerant systems incorporating a microchannel heat exchanger

Patent metadata

Field	Value
Publication number	US-2018372384-A1
Application number	US-201816118511-A
Country	US
Kind code	A1
Filing date	Aug 31, 2018
Priority date	Nov 3, 2009
Publication date	Dec 27, 2018
Grant date	—

Abstract

A refrigerant system includes at least one compressor that compresses refrigerant and delivers it downstream to a heat rejection heat exchanger. The heat rejection heat exchanger is a microchannel heat exchanger. Refrigerant passes from the heat rejection heat exchanger downstream to an expansion device, from the expansion device through an evaporator, and from the evaporator back to the at least one compressor. A control operates at least one compressor and the expansion device to reduce pressure spikes at transient conditions.

First claim

What is claimed is:

1 . A refrigerant system comprising:
at least one compressor, said compressor compressing refrigerant and delivering it downstream to a heat rejection heat exchanger, said heat rejection heat exchanger being a microchannel heat exchanger, said microchannel heat exchanger includes a plurality of parallel flow channels having a hydraulic diameter of less than 3 mm, an expansion device downstream of said heat rejection heat exchanger, and an evaporator downstream of said expansion device; a control programmed for operating at least one of said at least one compressor and said expansion device to reduce pressure spikes at transient conditions; wherein said control operates said at least one compressor to reduce pressure spikes at transient conditions using at least one of the these following control steps; said at least one compressor being operated with a series of on and off cycles at the transient conditions; or wherein said at least one compressor can operate in an unloaded fashion, and said control operates said at least one compressor to be at least partially unloaded at the transient conditions; or wherein said at least one compressor includes at least two compressors, and the operation at transient conditions includes turning off at least one of said at least two compressors.

2 . The refrigerant system as set forth in claim 1 , wherein said compressor is operated with a series of on and off cycles at the transient conditions.

3 . The refrigerant system as set forth in claim 1 , wherein said at least one compressor can operate in an unloaded fashion, and said control operates said at least one compressor to be at least partially unloaded at the transient conditions.

4 . The refrigerant system as set forth in claim 1 , wherein said at least one compressor includes at least two compressors, and the operation at transient conditions includes turning off at least one of said at least two compressors.

5 . The refrigerant system as set forth in claim 1 , wherein a sensor senses a condition within the refrigerant system, and is operable in combination with said control to stop operation of said refrigerant system should said condition be indicative of an undesirable condition.

6 . The refrigerant system as set forth in claim 1 , wherein feedback from the refrigerant system is provided to the control, and said control using the feedback to change the way it operates the refrigerant system at the transient conditions.

7 . The refrigerant system as set forth in claim 6 , wherein said control utilizes the feedback to learn parameters for future operation of the control, to achieve better reduction of the pressure spikes.

8 . A refrigerant system comprising:
at least one compressor, said compressor compressing refrigerant and delivering it downstream to a heat rejection heat exchanger, said heat rejection heat exchanger being a microchannel heat exchanger, said microchannel heat exchanger includes a plurality of parallel flow channels having a hydraulic diameter of less than 3 mm, an expansion device downstream of said heat rejection heat exchanger, and an evaporator downstream of said expansion device; a control programmed for operating at least one of said at least one compressor and said expansion device to reduce pressure spikes at the transient conditions; wherein said control operates said at least one compressor to reduce pressure spikes at the transient conditions; and wherein said expansion device is also operated by said control to be in a more open condition during the transient conditions.

9 . The refrigerant system as set forth in claim 8 , wherein said expansion device is an electronic expansion device, and is controlled to be in a more open condition during at least part of the transient condition.

10 . The refrigerant system as set forth in claim 8 , wherein said expansion device is a thermostatic expansion device, and a heater is associated with a bulb for said thermostatic expansion device, and is operated at the transient condition to apply heat to the bulb.

11 . The refrigerant system as set forth in claim 8 , wherein said transient conditions includes refrigerant system start-up.

12 . The refrigerant system as set forth in claim 8 , wherein a sensor senses a condition within the refrigerant system, and is operable in combination with said control to stop operation of said refrigerant system should said condition be indicative of an undesirable condition.

13 . The refrigerant system as set forth in claim 8 , wherein feedback from the refrigerant system is provided to the control, and said control using the feedback to change the way it operates the refrigerant system at the transient conditions.

14 . The refrigerant system as set forth in claim 13 , wherein said control utilizes the feedback to learn parameters for future operation of the control, to achieve better reduction of the pressure spikes.

15 . A refrigerant system comprising:
at least one compressor, said compressor compressing refrigerant and delivering it downstream to a heat rejection heat exchanger, said heat rejection heat exchanger being a microchannel heat exchanger, said microchannel heat exchanger includes a plurality of parallel flow channels having a hydraulic diameter of less than 3 mm, an expansion device downstream of said heat rejection heat exchanger, and an evaporator downstream of said expansion device; a control programmed for operating at least one of said at least one compressor and said expansion device to reduce pressure spikes at transient conditions; wherein said control operates said at least one compressor to reduce pressure spikes at the transient conditions; wherein said at least one compressor includes at least two compressors, and the operation at transient conditions includes turning off at least one of said at least two compressors; and wherein a sensor senses a condition within the refrigerant system, and is operable in combination with said control to stop operation of said refrigerant system should said condition be indicative of an undesirable condition.

16 . The refrigerant system as set forth in claim 15 , wherein a bypass line is provided for a refrigerant bypass around said expansion device during transient conditions, and a valve is provided on said bypass line, and said valve being opened during said transient condition.

17 . The refrigerant system as set forth in claim 16 , wherein feedback from the refrigerant system is provided to the control, and said control using the feedback to change the way it operates the refrigerant system at the transient conditions.

18 . The refrigerant system as set forth in claim 17 , wherein said control utilizes the feedback to learn parameters for future operation of the control, to achieve better reduction of the pressure spikes.

19 . The refrigerant system as set forth in claim 15 , wherein feedback from the refrigerant system is provided to the control, and said control using the feedback to change the way it operates the refrigerant system at the transient conditions.

20 . The refrigerant system as set forth in claim 19 , wherein said control utilizes the feedback to learn parameters for future operation of the control, to achieve better reduction of the pressure spikes.

Assignees

• Carrier Corp

Inventors

• Taras Michael F
• Lifson Alexander

Classifications

• F25B2600/0253

  with variable speed · CPC title

• F25B2500/07

  Exceeding a certain pressure value in a refrigeration component or cycle · CPC title

• F25B2400/075

  with parallel compressors · CPC title

• Y02B30/741

  Cross-Sectional Technologies · mapped topic

• F25B2700/1931

  Discharge pressures · CPC title