Monitoring refrigerant in a refrigeration system

• US 7,594,407 B2
• Filed: 10/21/2005
• Issued: 09/29/2009
• Est. Priority Date: 10/21/2005
• Status: Active Grant

• Current Assignee: Copeland Cold Chain LP
• Original Assignee: Emerson Climate Technologies Incorporated (Emerson Electric Company)
• Inventors: Singh, Abtar, Mitchell, James R.
• Primary Examiner(s): JIANG, CHEN WEN
• Application Number:
  US11/256,641
• Publication Number:
  US 20070089438A1
• Time in Patent Office: 1,439 Days
• Field of Search: 621/29, 621/49, 622/92, 623/244
• US Class Current: 62/129
• CPC Class Codes: F25B 2700/04 Refrigerant level
• CPC Class Codes: F25B 2700/1931 Discharge pressures
• CPC Class Codes: F25B 2700/21152 at the discharge side of the compressor
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence

Abstract

A method for monitoring refrigerant in a refrigeration system includes calculating a saturation temperature of refrigerant in a refrigeration system based on at least one of a discharge pressure and a discharge temperature of the refrigeration system; calculating an expected refrigerant level based on the saturation temperature; comparing the refrigerant level with the refrigerant level threshold; and generating a leak notification when the receiver refrigerant level is less than the refrigerant level threshold. The method may be executed by a controller or stored in a computer-readable medium.

Claims

1. A method comprising:

receiving a refrigerant level signal that corresponds to a refrigerant level in a refrigeration system;

receiving at least one of a discharge pressure signal that corresponds to a discharge pressure of a compressor of the refrigeration system and a discharge temperature signal that corresponds to a discharge temperature of the compressor;

receiving an ambient temperature signal that corresponds to an ambient temperature;

calculating a saturation temperature of refrigerant in said refrigeration system based on at least one of said discharge pressure and said discharge temperature of said compressor;

calculating a temperature difference between said saturation temperature and said ambient temperature;

calculating an expected refrigerant level based on said temperature difference;

comparing said refrigerant level of said refrigeration system with said expected refrigerant level; and

generating a leak notification when said refrigerant level is less than said expected refrigerant level.

2. The method of claim 1, further comprising receiving said refrigerant level signal from a refrigerant level sensor that generates said refrigerant level signal.

3. A controller that executes the method of claim 2.

4. A computer-readable medium having computer-executable instructions for performing the method of claim 2.

5. The method of claim 1, further comprising receiving said discharge pressure signal from a discharge pressure sensor that generates said discharge pressure signal.

6. A controller that executes the method of claim 5.

7. A computer-readable medium having computer-executable instructions for performing the method of claim 5.

8. The method of claim 1, further comprising receiving said discharge temperature signal from a discharge temperature sensor that generates said discharge temperature signal.

9. A controller that executes the method of claim 8.

10. A computer-readable medium having computer-executable instructions for performing the method of claim 8.

11. The method of claim 1, further comprising:

receiving said ambient temperature signal from an ambient temperature sensor that generates said ambient temperature signal.

12. A controller that executes the method of claim 11.

13. A computer-readable medium having computer-executable instructions for performing the method of claim 11.

14. The method of claim 1, further comprising receiving refrigerant type data, wherein said calculating said saturation temperature is based on said refrigerant type data.

15. A controller that executes the method of claim 14.

16. A computer-readable medium having computer-executable instructions for performing the method of claim 14.

17. The method of claim 1, further comprising:

monitoring said refrigerant level for a predetermined initial period;

generating a refrigerant level model based on said monitoring;

calculating said expected refrigerant level based on said refrigerant level model;

calculating a refrigerant level average over a predetermined period;

comparing said refrigerant level average to said expected refrigerant level; and

generating said leak notification when a difference between said refrigerant level average and said expected refrigerant level is greater than a predetermined refrigerant level difference threshold.

18. A controller that executes the method of claim 17.

19. The method of claim 17, further comprising:

monitoring said difference between said refrigerant level average and said expected refrigerant level;

wherein said generating said leak notification occurs when said difference between said refrigerant level average and said expected refrigerant level increases over said predetermined period.

20. A controller that executes the method of claim 19.

21. A computer-readable medium having computer-executable instructions for performing the method of claim 19.

22. A computer-readable medium having computer-executable instructions for performing the method of claim 17.

23. A controller that executes the method of claim 1.

24. A computer-readable medium having computer-executable instructions for performing the method of claim 1.