Predictive maintenance and equipment monitoring for a refrigeration system

• US 20040261431A1
• Filed: 04/27/2004
• Published: 12/30/2004
• 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: Singh, Abtar, Mathews, Thomas J., Woodworth, Stephen T.
• Granted Patent: US 7,490,477 B2
• Time in Patent Office: Days
• US Class Current: 62/125
• 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 for monitoring a remote refrigeration system includes a plurality of sensors that monitor parameters of components of the refrigeration system and a communication network that transfers signals generated by each of the plurality of sensors. A management center receives the signals from the communication network and processes the signals to determine an operating condition of at least one of the components. The management center generates an alarm based on the operating condition.

Claims

1. A system for monitoring a remote refrigeration system, the system comprising:

a plurality of sensors that monitor parameters of components of said refrigeration system;

a communication network that transfers signals generated by each of said plurality of sensors; and

a management center that receives said signals from said communication network, said management center processing said signals to determine an operating condition of at least one of said components and generating an alarm based on said operating condition.

2. The system of claim 1, wherein said management center evaluates each of said signals to determine whether each of said signals is within a useful range, to determine whether each of said signals is dynamic and to determine whether each of said signals is valid.

3. The system of claim 1, further comprising a temperature sensor that monitors a temperature of a refrigerant flowing through said refrigeration system and that generates a temperature signal.

4. The system of claim 3, wherein said management center calculates a pressure, a density and an enthalpy of said refrigerant based on said temperature and based on whether said refrigerant is in one of a saturated liquid phase and a saturated vapor phase.

5. The system of claim 1, further comprising a pressure sensor that monitors a pressure of a refrigerant flowing through said refrigeration system and that generates a pressure signal.

6. The system of claim 5, wherein said management center calculates a temperature, a density and an enthalpy of said refrigerant based on said pressure and based on whether said refrigerant is in one of a saturated liquid phase and a saturated vapor phase.

7. The system of claim 1, further comprising:

a temperature sensor that monitors a temperature of a refrigerant at a suction side of a compressor of said refrigeration system and that generates a temperature signal; and

a pressure sensor that monitors a pressure of a refrigerant at said suction side of said compressor and that generates a pressure signal;

wherein said management center determines an occurrence of a floodback event based on said temperature signal and said pressure signal.

8. The system of claim 7, wherein said management center determines a superheat temperature of said refrigerant based on said temperature signal and said pressure signal and observes a pattern of said superheat over a time period to determine whether said floodback event has occurred.

9. The system of claim 1, further comprising:

a temperature sensor that monitors a temperature of a refrigerant at a discharge side of a compressor of said refrigeration system and that generates a temperature signal; and

a pressure sensor that monitors a pressure of a refrigerant at said discharge side of said compressor and that generates a pressure signal;

wherein said management center determines an occurrence of a floodback event based on said temperature signal and said pressure signal.

10. The system of claim 9, wherein said management center determines a superheat temperature of said refrigerant based on said temperature signal and said pressure signal observes a pattern of said superheat over a time period to determine whether said floodback event has occurred.

11. The system of claim 1, further comprising a contactor associated with one of said components and that is cycled between an open position and a closed position to selectively operate said component.

12. The system of claim 11, wherein said management center monitors cycling of said contactor and generates an alarm when one of a cycling rate is exceeded and a maximum number of cycles is exceeded.

13. The system of claim 1, further comprising:

an ambient condenser temperature sensor that generates an ambient temperature signal;

a condenser pressure sensor that generates a pressure signal;

a compressor current sensor that generates a compressor current signal; and

a condenser current sensor that generates a condenser current signal;

wherein said management center determines an operating condition of said condenser based on said ambient temperature signal, said pressure signal, said compressor current signal and said condenser current signal.

14. The system of claim 13, wherein said management center determines a power consumption of said condenser, observes said power consumption over a period of time and selectively generates an alarm based on a pattern of said power consumption.

15. A method monitoring a refrigeration system at a remote location, comprising the steps of:

generating signals from a plurality of sensors that monitor parameters of components of said refrigeration system;

transferring signals generated by each of said plurality of sensors over a communication network;

processing said signals to determine an operating condition of at least one of said components; and

generating an alarm based on said operating condition.

16. The method of claim 15, further comprising evaluating each of said signals to determine whether each of said signals is within a useful range, to determine whether each of said signals is dynamic and to determine whether each of said signals is valid.

17. The method of claim 15, further comprising:

monitoring a temperature of a refrigerant flowing through said refrigeration system; and

generating a temperature signal based on said temperature.

18. The method of claim 17, further comprising calculating a pressure, a density and an enthalpy of said refrigerant based on said temperature and based on whether said refrigerant is in one of a saturated liquid phase and a saturated vapor phase.

19. The method of claim 15, further comprising:

monitoring a pressure of a refrigerant flowing through said refrigeration system; and

generating a pressure signal based on said pressure.

20. The method of claim 19, further comprising calculating a temperature, a density and an enthalpy of said refrigerant based on said pressure and based on whether said refrigerant is in one of a saturated liquid phase and a saturated vapor phase.

21. The method of claim 15, further comprising:

monitoring a temperature of a refrigerant at a suction side of a compressor of said refrigeration system;

generating a temperature signal based on said temperature;

monitoring a pressure of a refrigerant at said suction side of said compressor;

generating a pressure signal based on said pressure; and

determining an occurrence of a floodback event based on said temperature signal and said pressure signal.

22. The method of claim 21, further comprising:

determining a superheat temperature of said refrigerant based on said temperature signal and said pressure signal; and

observing a pattern of said superheat over a time period to determine whether said floodback event has occurred.

23. The system of claim 15, further comprising:

monitoring a temperature of a refrigerant at a discharge side of a compressor of said refrigeration system;

generating a temperature signal based on said temperature; and

monitoring a pressure of a refrigerant at said discharge side of said compressor;

generating a pressure signal based on said pressure; and

determining an occurrence of a floodback event based on said temperature signal and said pressure signal.

24. The method of claim 23, further comprising:

determining a superheat temperature of said refrigerant based on said temperature signal and said pressure signal; and

observing a pattern of said superheat over a time period to determine whether said floodback event has occurred.

25. The method of claim 15, further comprising a cycling a contactor associated with one of said components between an open position and a closed position to selectively operate said component.

26. The method of claim 25, further comprising:

monitoring said cycling of said contactor; and

generating an alarm when one of a cycling rate is exceeded and a maximum number of cycles is exceeded.

27. The method of claim 15, further comprising:

generating an ambient temperature signal based on an ambient air temperature of a condenser;

generating a pressure signal based on a condenser pressure;

generating a compressor current signal based on a compressor current;

generating a condenser current signal based on a condenser current; and

determining an operating condition of said condenser based on said ambient temperature signal, said pressure signal, said compressor current signal and said condenser current signal.

28. The method of claim 27, further comprising:

determining a power consumption of said condenser;

observing said power consumption over a period of time; and

selectively generating an alarm based on a pattern of said power consumption.

29. A system for monitoring a remote refrigeration system, the system comprising:

a plurality of sensors that monitor parameters of components of said refrigeration system;

a communication network that transfers signals generated by each of said plurality of sensors; and

a management center that receives said signals from said communication network, said management center processing said signals to determine an operating condition of at least one of said components, monitoring a pattern of said signals over time and selectively generating an alarm based on said pattern.

30. The system of claim 29, wherein said management center 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 a defined time period.

31. The system of claim 30, wherein an alarm is generated when a population of a particular band exceeds a threshold associated with said particular band.

32. The system of claim 29, wherein said management center evaluates each of said signals to determine whether each of said signals is within a useful range, to determine whether each of said signals is dynamic and to determine whether each of said signals is valid.

33. The system of claim 29, further comprising a temperature sensor that monitors a temperature of a refrigerant flowing through said refrigeration system and that generates a temperature signal.

34. The system of claim 33, wherein said management center calculates a pressure, a density and an enthalpy of said refrigerant based on said temperature and based on whether said refrigerant is in one of a saturated liquid phase and a saturated vapor phase.

35. The system of claim 29, further comprising a pressure sensor that monitors a pressure of a refrigerant flowing through said refrigeration system and that generates a pressure signal.

36. The system of claim 35, wherein said management center calculates a temperature, a density and an enthalpy of said refrigerant based on said pressure and based on whether said refrigerant is in one of a saturated liquid phase and a saturated vapor phase.

37. The system of claim 29, further comprising:

a temperature sensor that monitors a temperature of a refrigerant at a suction side of a compressor of said refrigeration system and that generates a temperature signal; and

a pressure sensor that monitors a pressure of a refrigerant at said suction side of said compressor and that generates a pressure signal;

wherein said management center determines an occurrence of a floodback event based on said temperature signal and said pressure signal.

38. The system of claim 37, wherein said management center determines a superheat temperature of said refrigerant based on said temperature signal and said pressure signal and observes a pattern of said superheat over a time period to determine whether said floodback event has occurred.

39. The system of claim 29, further comprising:

a temperature sensor that monitors a temperature of a refrigerant at a discharge side of a compressor of said refrigeration system and that generates a temperature signal; and

a pressure sensor that monitors a pressure of a refrigerant at said discharge side of said compressor and that generates a pressure signal;

wherein said management center determines an occurrence of a floodback event based on said temperature signal and said pressure signal.

40. The system of claim 39, wherein said management center determines a superheat temperature of said refrigerant based on said temperature signal and said pressure signal observes a pattern of said superheat over a time period to determine whether said floodback event has occurred.

41. The system of claim 29, further comprising:

an ambient condenser temperature sensor that generates an ambient temperature signal;

a condenser pressure sensor that generates a pressure signal;

a compressor current sensor that generates a compressor current signal; and

a condenser current sensor that generates a condenser current signal;

wherein said management center determines an operating condition of said condenser based on said ambient temperature signal, said pressure signal, said compressor current signal and said condenser current signal.

42. A method of monitoring a remote refrigeration system, comprising:

generating signals from a plurality of sensors that monitor parameters of components of said refrigeration system;

transferring signals generated by each of said plurality of sensors over a communication network;

processing said signals to determine an operating condition of at least one of said components;

monitoring a pattern of said signals over time; and

selectively generating an alarm based on said pattern.

43. The method of claim 42, 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 a defined time period.

44. The method of claim 43, further comprising generating an alarm when a population of a particular band exceeds a threshold associated with said particular band.

45. The method of claim 42, further comprising evaluating each of said signals to determine whether each of said signals is within a useful range, to determine whether each of said signals is dynamic and to determine whether each of said signals is valid.

46. The method of claim 42, further comprising:

monitoring a temperature of a refrigerant flowing through said refrigeration system; and

generating a temperature signal based on said temperature.

47. The method of claim 46, further comprising calculating a pressure, a density and an enthalpy of said refrigerant based on said temperature and based on whether said refrigerant is in one of a saturated liquid phase and a saturated vapor phase.

48. The method of claim 42, further comprising:

monitoring a pressure of a refrigerant flowing through said refrigeration system; and

generating a pressure signal based on said pressure.

49. The method of claim 48, further comprising calculating a temperature, a density and an enthalpy of said refrigerant based on said pressure and based on whether said refrigerant is in one of a saturated liquid phase and a saturated vapor phase.

50. The method of claim 42, further comprising:

monitoring a temperature of a refrigerant at a suction side of a compressor of said refrigeration system;

generating a temperature signal based on said temperature;

monitoring a pressure of a refrigerant at said suction side of said compressor;

generating a pressure signal based on said pressure; and

determining an occurrence of a floodback event based on said temperature signal and said pressure signal.

51. The method of claim 50, further comprising:

determining a superheat temperature of said refrigerant based on said temperature signal and said pressure signal; and

observing a pattern of said superheat over a time period to determine whether said floodback event has occurred.

52. The system of claim 42, further comprising:

monitoring a temperature of a refrigerant at a discharge side of a compressor of said refrigeration system;

generating a temperature signal based on said temperature; and

monitoring a pressure of a refrigerant at said discharge side of said compressor;

generating a pressure signal based on said pressure; and

determining an occurrence of a floodback event based on said temperature signal and said pressure signal.

53. The method of claim 52, further comprising:

determining a superheat temperature of said refrigerant based on said temperature signal and said pressure signal; and

observing a pattern of said superheat over a time period to determine whether said floodback event has occurred.

54. The method of claim 42, further comprising:

generating an ambient temperature signal based on an ambient air temperature of a condenser;

generating a pressure signal based on a condenser pressure;

generating a compressor current signal based on a compressor current;

generating a condenser current signal based on a condenser current; and

determining an operating condition of said condenser based on said ambient temperature signal, said pressure signal, said compressor current signal and said condenser current signal.

55. The method of claim 54, further comprising:

determining a power consumption of said condenser;

observing said power consumption over a period of time; and

selectively generating an alarm based on a pattern of said power consumption.