System and method for monitoring a compressor of a refrigeration system

• US 7,845,179 B2
• Filed: 12/03/2008
• Issued: 12/07/2010
• Est. Priority Date: 04/30/2003
• Status: Active Grant

• Current Assignee: Copeland Cold Chain LP
• Original Assignee: Emerson Retail Services, Inc. (Emerson Electric Company)
• Inventors: Matthews, Thomas J., Singh, Abtar, Woodworth, Stephen T.
• Primary Examiner(s): Norman; Marc E
• Application Number:
  US12/327,273
• Publication Number:
  US 20090077983A1
• Time in Patent Office: 734 Days
• Field of Search: 621/26, 621/29, 621/57, 622/17, 622/25, 621/25, 622/283
• US Class Current: 62/129
• CPC Class Codes: F25B 2400/075 with parallel compressors
• CPC Class Codes: F25B 2400/22 Refrigeration systems for supermarkets
• CPC Class Codes: F25B 2500/19 Calculation of parameters
• CPC Class Codes: F25B 2600/07 Remote controls
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence

Abstract

A system includes a compressor temperature sensor that generates a compressor discharge temperature signal corresponding to a compressor of a refrigeration system, a compressor pressure sensor that generates a compressor discharge pressure signal corresponding to the compressor, and a controller processing the signals over a predetermined time period. The processing includes calculating a discharge saturation temperature based on the compressor discharge pressure signal, calculating compressor superheat data based on the compressor discharge temperature signal and the discharge saturation temperature, accumulating the compressor superheat data over the predetermined time period, and comparing the accumulated compressor superheat data to a predetermined threshold. The controller generates an alarm indicating a compressor fault based on the comparing.

Claims

1. A system comprising:

a compressor temperature sensor that generates a compressor discharge temperature signal corresponding to a compressor of a refrigeration system;

a compressor pressure sensor that generates a compressor discharge pressure signal corresponding to said compressor;

a controller processing said signals over a predetermined time period, said processing including receiving a refrigerant type indicating a particular type of refrigerant in the refrigeration system, determining a discharge saturation temperature based on said compressor discharge pressure signal and said refrigerant type using a lookup table linking refrigerant types and discharge pressures to predetermined discharge saturation suction temperatures, calculating compressor superheat data based on said compressor discharge temperature signal and said discharge saturation temperature, accumulating said compressor superheat data over said predetermined time period, and comparing said accumulated compressor superheat data to a predetermined threshold,

said controller generating an alarm indicating a compressor fault based on said comparing.

2. The system of claim 1, wherein said processing of said signals includes determining whether each of said signals is within a useful range, determining whether each of said signals is dynamic and determining whether each of said signals is valid.

3. The system of claim 1, wherein said controller communicates said alarm over a communication network to a remote processing center.

4. The system of claim 1, wherein said controller observes a pattern of said compressor superheat data to determine whether a floodback event has occurred.

5. The system of claim 1, wherein said controller accumulates compressor superheat data for each compressor of a plurality of compressors positioned within a compressor rack, compares said accumulated compressor superheat data for said each compressor, and generates an alarm indicating a compressor fault for each compressor positioned within said compressor rack based on said comparing.

6. The system of claim 1, wherein said controller determines a plurality of bands that define ranges associated with each of said signals and populates each band based on values of said signals that are observed over said predetermined time period.

7. The system of claim 6, wherein said alarm is generated when a population of a particular band exceeds a threshold associated with said particular band.

8. A non-transitory computer readable medium having machine executable instructions stored thereon for execution by a processor to perform a method comprising:

receiving a compressor discharge temperature signal from a compressor temperature sensor corresponding to a compressor of a refrigeration system;

receiving a compressor discharge pressure signal from a compressor pressure sensor corresponding to said compressor;

processing said signals over a predetermined time period, said processing including receiving a refrigerant type indicating a particular type of refrigerant in the refrigeration system, determining a discharge saturation temperature based on said compressor discharge pressure signal and said refrigerant type using a lookup table linking refrigerant types and discharge pressures to predetermined discharge saturation suction temperature, calculating compressor superheat data based on said compressor discharge temperature signal and said discharge saturation temperature, accumulating said compressor superheat data over said predetermined time period, and comparing said accumulated compressor superheat data to a predetermined threshold;

generating an alarm indicating a compressor fault based on said comparing.

9. The non-transitory computer readable medium recited by claim 8, the method further comprising determining whether each of said signals is within a useful range, determining whether each of said signals is dynamic and determining whether each of said signals is valid.

10. The non-transitory computer readable medium recited by claim 8, the method further comprising communicating said alarm over a communication network to a remote processing center.

11. The non-transitory computer readable medium recited by claim 8, the method further comprising observing a pattern of said compressor superheat data to determine whether a floodback event has occurred.

12. The non-transitory computer readable medium recited by claim 8, the method further comprising accumulating compressor superheat data for each compressor of a plurality of compressors positioned within a compressor rack, comparing said accumulated compressor superheat data for said each compressor, and generating an alarm indicating a compressor fault for each compressor positioned within said compressor rack based on said comparing.

13. The non-transitory computer readable medium recited by claim 8, the method further comprising:

determining a plurality of bands that define ranges associated with each of said signals; and

populating each band based on values of said signals that are observed over said predetermined time period.

14. The non-transitory computer readable medium recited by claim 13, the method further comprising generating said alarm when a population of a particular band exceeds a threshold associated with said particular band.