Monitoring refrigerant in a refrigeration system

• US 7,752,853 B2
• Filed: 10/21/2005
• Issued: 07/13/2010
• Est. Priority Date: 10/21/2005
• Status: Active Grant

• Current Assignee: Copeland Cold Chain LP
• Original Assignee: Emerson Retail Services, Inc. (Emerson Electric Company)
• Inventors: Churiwal, Pawan K., Singh, Abtar, Gurkan, Ozgur Y., Mathews, Thomas J., Mitchell, James R., Woodworth, Stephen T.
• Primary Examiner(s): JIANG, CHEN WEN
• Application Number:
  US11/256,637
• Publication Number:
  US 20070089434A1
• Time in Patent Office: 1,726 Days
• Field of Search: 621/25, 621/26, 621/27, 621/29, 621/49, 622/82, 623/241
• US Class Current: 62/129
• CPC Class Codes: F25B 2500/19 Calculation of parameters
• CPC Class Codes: F25B 2700/19 Pressures
• CPC Class Codes: F25B 2700/1931 Discharge pressures
• CPC Class Codes: F25B 2700/1933 Suction pressures
• CPC Class Codes: F25B 49/02 for compression type machines, plants or systems
• CPC Class Codes: G01M 3/3227 for radiators

Abstract

A method for monitoring refrigerant in a refrigeration system includes sensing, a refrigerant pressure of a refrigeration system, averaging the refrigerant pressure over a time period, determining an expected pressure based on said time period, comparing the average to the expected pressure, and determining a system condition based on said comparison. The method may be executed by a controller or stored in a computer-readable medium.

Claims

1. A method comprising:

sensing refrigerant pressure in a refrigeration system;

calculating a first refrigerant pressure parameter based on sensing said refrigerant pressure over a first time period;

calculating a second refrigerant pressure parameter based on sensing said refrigerant pressure over a second time period, said second time period occurring after said first time period;

calculating a difference between said first refrigerant pressure parameter and said second refrigerant pressure parameter;

comparing said difference between said first and second refrigerant pressure parameters and a predetermined threshold; and

determining a system condition based on said comparison.

2. The method of claim 1, wherein said refrigerant pressure is at least one of a suction pressure and a discharge pressure.

3. A controller configured with programming stored in a computer readable medium to execute the method of claim 2.

4. A computer-readable medium having computer-executable instructions for execution by a controller to perform the method of claim 2.

5. The method of claim 1, wherein said system condition includes at least one of a refrigeration system malfunction and a set-point change.

6. The method of claim 5, wherein said refrigerator system malfunction comprises a sensor malfunction.

7. A controller configured with programming stored in a computer readable medium to execute the method of claim 6.

8. A computer-readable medium having computer-executable instructions for execution by a controller to perform the method of claim 6.

9. A controller configured with programming stored in a computer readable medium to execute the method of claim 5.

10. A computer-readable medium having computer-executable instructions for execution by a controller to perform the method of claim 5.

11. The method of claim 1, further comprising generating a notification based on said determining.

12. A controller configured with programming stored in a computer readable medium to execute the method of claim 11.

13. A computer-readable medium having computer-executable instructions for execution by a controller to perform the method of claim 11.

14. A controller configured with programming stored in a computer readable medium to execute the method of claim 1.

15. A computer-readable medium having computer-executable instructions for execution by a controller to perform the method of claim 1.

16. The method of claim 1, wherein said calculating said first refrigerant pressure parameter includes averaging said refrigerant pressure over said first time period and said calculating said second refrigerant pressure parameter includes averaging said refrigerant pressure over said second time period.

17. A controller configured with programming stored in a computer readable medium to execute the method of claim 16.

18. A computer-readable medium having computer-executable instructions for execution by a controller to perform the method of claim 16.

19. The method of claim 1, wherein said first time period is a first day and said second time period is a second day.

20. A controller configured with programming stored in a computer readable medium to execute the method of claim 19.

21. A computer-readable medium having computer-executable instructions for execution by a controller to perform the method of claim 19.

22. The method of claim 1, wherein said second time period is a current day and said first time period is a previous day.

23. The method of claim 1, wherein said comparing includes determining whether an absolute value of said difference is greater than said predetermined threshold.

24. A controller configured with programming stored in a computer readable medium to execute the method of claim 23.

25. A computer-readable medium having computer-executable instructions for execution by a controller to perform the method of claim 23.

26. A method comprising:

sensing suction pressure and discharge pressure in a refrigeration system;

calculating a first suction pressure parameter based on sensing said suction pressure over a first time period;

calculating a second suction pressure parameter based on sensing said suction pressure over a second time period, said second time period occurring after said first time period;

calculating a second discharge pressure parameter based on sensing said discharge pressure over said second time period;

comparing a difference between said first and second suction pressure parameters to a predetermined suction pressure threshold;

issuing a first system notification when said difference between said first and second suction pressure parameters is greater than said predetermined suction pressure threshold; and

when said difference between said first and second suction pressure parameters is less than said predetermined suction pressure threshold, comparing a difference between said first discharge pressure parameter and said second discharge pressure parameter to a predetermined discharge pressure threshold and issuing a second system notification when said difference between said first and second pressure parameters is greater than said predetermined discharge pressure threshold.

27. The method of claim 26 wherein at least one of said first system notification and said second system notification includes a notification of at least one of a refrigeration system malfunction and a set-point change.

28. The method of claim 27, wherein said refrigeration system malfunction comprises a sensor malfunction.

29. A controller configured with programming stored in a computer readable medium to execute the method of claim 27.

30. A computer-readable medium having computer-executable instructions for execution by a controller to perform the method of claim 27.

31. A controller configured with programming stored in a computer readable medium to execute the method of claim 26.

32. A computer-readable medium having computer-executable instructions for execution by a controller to perform the method of claim 26.