Monitoring a condenser in a refrigeration system

• US 7,752,854 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: Mitchell, James R., Woodworth, Stephen T., Singh, Abtar
• Primary Examiner(s): JIANG, CHEN WEN
• Application Number:
  US11/256,659
• Publication Number:
  US 20070089439A1
• Time in Patent Office: 1,726 Days
• Field of Search: 621/29, 622/08, 622/09, 622/30, 621/25, 621/26, 621/27, 702/182, 702/183, 702/184, 165/11.1, 236/94
• US Class Current: 62/129
• CPC Class Codes: F25B 2500/19 Calculation of parameters
• CPC Class Codes: F25B 2600/111 of condenser fans
• 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 49/02 for compression type machines, plants or systems

Abstract

A method for monitoring a condenser in a refrigeration system includes calculating a thermal efficiency of the condenser based on operation of the condenser and averaging the thermal efficiency over a predetermined period. Further, the method comprises comparing the average to an efficiency threshold and generating a notification based on the comparison. The method may be executed by a controller or stored in a computer-readable medium.

Claims

1. A method comprising:

receiving a condenser signal including at least one of a condenser current signal corresponding to an electrical current of a condenser fan of a condenser of a refrigeration system, a condenser fan power signal corresponding to an electrical power of said condenser fan, and a condenser fan control signal for controlling said condenser fan;

receiving a compressor signal including at least one of a compressor current signal corresponding to an electrical current of a compressor of said refrigeration system, a compressor power signal corresponding to an electrical power of said compressor, and a compressor control signal for controlling said compressor;

receiving a discharge signal corresponding to at least one of a discharge pressure of said compressor and a discharge temperature of said compressor;

calculating a saturation temperature based on said discharge signal;

calculating a thermal efficiency of said condenser of said refrigeration system based on said condenser signal, said compressor signal, and said saturation temperature;

comparing said thermal efficiency to an efficiency threshold; and

generating a notification based on said comparison.

2. The method of claim 1, further comprising calculating said efficiency threshold based on a predetermined percentage of a benchmark thermal efficiency of said condenser.

3. The method of claim 2, wherein said benchmark thermal efficiency corresponds to said thermal efficiency of said condenser when at least one of said condenser is clean and said condenser is initialized.

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

5. A computer-readable medium having computer-executable instructions for execution by a controller to perform the method of claim 3.

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

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

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

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

10. The method of claim 1, further comprising:

receiving an ambient temperature signal corresponding to an ambient temperature; and

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

wherein said calculating said thermal efficiency of said condenser of said refrigeration system is based on said difference.

11. A controller configured with programming stored in a computer readable medium to execute the method of claim 10.

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

13. The method of claim 10, said condenser signal including said condenser current signal, said method further comprising calculating a product of said electrical current of said condenser fan, wherein said calculating said thermal efficiency of said condenser of said refrigeration system is based on said product.

14. A controller configured with programming stored in a computer readable medium to execute the method of claim 13.

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

16. The method of claim 13, said compressor signal including said compressor current signal, said method further comprising calculating a ratio of said electrical current of said compressor to said product, wherein said calculating said thermal efficiency of said condenser of said refrigeration system is based on said ratio.

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, further comprising calculating an average of said thermal efficiency over a predetermined time period, wherein said comparing said thermal efficiency includes comparing said average to said efficiency threshold.

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, further comprising receiving a reset signal and calculating said efficiency threshold based on averaging said thermal efficiency of said condenser over an initial time period after receiving said reset signal.

23. A controller configured with programming stored in a computer readable medium to execute the method of claim 22.

24. A computer-readable medium having computer-executable instructions for execution by a controller to perform the method of claim 22.

25. The method of claim 22 wherein said reset signal is received when said condenser is cleaned.

26. A controller configured with programming stored in a computer readable medium to execute the method of claim 25.

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

28. A system comprising:

a first input for receiving a condenser signal including at least one of a condenser current signal corresponding to an electrical current of a condenser fan of a condenser of a refrigeration system, a condenser fan power signal corresponding to an electrical power of said condenser fan, and a condenser fan control signal for controlling said condenser fan;

a second input for receiving a compressor signal including at least one of a compressor current signal corresponding to an electrical current of a compressor of said refrigeration system, a compressor power signal corresponding to an electrical power of said compressor, and a compressor control signal for controlling said compressor;

a third input for receiving a discharge pressure signal corresponding to a discharge pressure of said compressor;

a fourth input for receiving an ambient temperature signal corresponding to an ambient temperature;

a controller, in communication with said first, second, third, and fourth inputs, that calculates a condenser performance factor corresponding to a thermal efficiency of said condenser based on said condenser signal, said compressor signal, said discharge pressure signal, and said ambient temperature signal, that calculates an average of said condenser performance factor over a predetermined time period, that compares said average to a benchmark factor, and that generates a notification based on said comparison.

29. The system of claim 28 further comprising a fifth input for receiving a reset signal, said controller in communication with said fifth input and calculating said benchmark factor by averaging said condenser performance factor over an initial time period after receiving said reset signal.

30. The system of claim 29 wherein said reset signal is received when said condenser is cleaned.

31. The system of claim 28 wherein said controller calculates a saturation temperature based on said discharge pressure, calculates a difference between said saturation temperature and said ambient temperature, and calculates said condenser performance factor based on said difference.

32. The system of claim 31 wherein said first input includes said condenser current signal, said second input includes said compressor current signal, and wherein said controller calculates a product of said electrical current of said condenser fan and said difference and calculates said condenser performance factor based on said electrical current of said compressor and said product.

33. The system of claim 32 wherein said controller calculates said condenser performance factor as a ratio of said electrical current of said compressor to said product.

34. The system of claim 28 wherein said notification indicates degraded condenser performance.