Distributed intelligence control for commercial refrigeration

• US 20020020175A1
• Filed: 05/04/2001
• Published: 02/21/2002
• Est. Priority Date: 03/14/2000
• Status: Active Grant

• Current Assignee: Hussmann Corporation (Panasonic Holdings Corporation)
• Original Assignee: Hussmann Corporation (Panasonic Holdings Corporation)
• Inventors: Thomas, Charles D., Street, Norman E., Sunderland, Ted W., Shapiro, Doron, Doerr, Dennis, DʼAnna, Michael J.
• Granted Patent: US 6,647,735 B2
• Time in Patent Office: Days
• US Class Current: 62/132
• CPC Class Codes: F25B 2400/075 with parallel compressors
• CPC Class Codes: F25B 2400/22 Refrigeration systems for supermarkets
• CPC Class Codes: F25B 25/005 using primary and secondary systems
• CPC Class Codes: F25B 2500/06 Damage
• CPC Class Codes: F25B 2600/07 Remote controls
• CPC Class Codes: F25B 2600/111 of condenser fans
• CPC Class Codes: F25B 2700/03 Oil level
• CPC Class Codes: F25B 2700/1931 Discharge pressures
• CPC Class Codes: F25B 2700/1933 Suction pressures
• CPC Class Codes: F25B 2700/21151 at the suction side of the compressor
• CPC Class Codes: F25B 2700/21152 at the discharge side of the compressor
• CPC Class Codes: F25B 2700/21157 at the coil or rotor
• CPC Class Codes: F25B 41/22 between evaporator and compressor
• CPC Class Codes: F25B 49/02 for compression type machines, plants or systems
• CPC Class Codes: F25B 49/022 Compressor control arrangements
• CPC Class Codes: F25B 5/02 arranged in parallel
• CPC Class Codes: F25B 6/04 arranged in series
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A commercial refrigeration system has a control system which distributes intelligence to increase granularity of the control and simplify wiring, assembly and installation. Compressors of the refrigeration system each have a bus compatible compressor safety and control module including a processor and sensors. All control and safety modules communicate over a single power and communications line with the controller, providing digital transmissions to the controller of measurements taken by the sensors. The information provided may include that the compressor is outside of a specific safety parameter, so that the controller knows not only that a safety parameter has been traversed, but exactly which one. The control and safety modules are capable of executing commands from the controller to cycle the compressors. The control and safety modules preferably contain sufficient intelligence to continue system operation upon failure of the controller. A compressor is also disclosed which has an intelligent control and safety module. The compressor also houses control and safety devices within a hermetically or semi-hermetically sealed shell. A condenser controller is also disclosed that is capable of communicating with the controller to affect intelligent control of one or more compressor fans. A valve controller is disclosed that is capable of communicating with the controller to facilitate distributed control of a system control valve with minimal wiring. A branch controller also communicates with the controller, resulting in distributed control of a refrigeration branch with minimal wiring required. Display/fixture control is achieved using display and control modules that collect data from a plurality of sensors on a common wiring harness. Wiring is also reduced by providing for wireless communication interfaces.

Claims

1. A commercial refrigeration system suitable for use in a supermarket, said system comprising:

an evaporator constructed and arranged to perform a cooling function;

a compressor in fluid communication with the evaporator for drawing refrigerant away from the evaporator;

a condenser in fluid communication with the compressor for receiving refrigerant from the compressor, the condenser being constructed and arranged for removing heat from the refrigerant;

an expansion valve in fluid communication with the condenser for receiving refrigerant from the condenser, the expansion valve being constructed and arranged for delivering refrigerant into the evaporator;

a master controller;

a compressor operating unit associated with the compressor, the operating unit being constructed and arranged for monitoring at least one operating parameter of the compressor and determining whether the operating parameter is within specification;

a first power and communication line extending from the master controller to the compressor operating unit and providing electrical power for the compressor operating unit, wherein the master controller and compressor operating unit are constructed and arranged for digital communication over the power and communication line such that no separate power line for the operating unit must be wired upon installation of the system;

a condenser fan associated with the condenser and providing air cooling to remove heat from the refrigerant;

a condenser controller in digital communication with the master controller and being capable of providing a fan control signal, said condenser controller being constructed and arranged for monitoring at least one operating parameter of the condenser;

a fan control unit associated with the condenser fan for controlling an operation of the condenser fan in response to the fan control signal;

a second power and communication line extending from the condenser controller to the fan control unit and providing electrical power for the fan control unit;

an electronically controlled valve;

a valve controller in digital communication with the master controller, said valve controller being constructed and arranged for providing a valve control signal to the electronically controlled valve to position said electronically controlled valve at a desired setting in response to a valve control signal from the master controller;

at least one branch control switch constructed and arranged for controlling a flow of refrigerant; and

a branch controller in digital communication with the master controller, said branch controller being constructed and arranged for providing at least one branch control signal to the at least one branch control switch in response to a branch control command from the master controller.

2. The commercial refrigeration system of claim 1 wherein the first power and communication line extends from the master controller to the valve controller and provides electrical power for the valve controller such that the master controller and valve controller communicate digitally over the first power and communication line and no separate power line for the valve controller must be wired upon installation of the system.

3. The commercial refrigeration system of claim 1 wherein the first power and communication line extends from the master controller to the branch controller and provides electrical power for the branch controller such that the master controller and branch controller communicate digitally over the first power and communication line and no separate power line for the branch controller must be wired upon installation of the system.

4. The commercial refrigeration system of claim 1 further comprising a communication channel extending from the master controller to the valve controller wherein the master controller and the valve controller communicate digitally over the communication channel.

5. The commercial refrigeration system of claim 4 wherein the communication channel comprises a wireless communication channel.

6. The commercial refrigeration system of claim 1 further comprising a communication channel extending from the master controller to the branch controller wherein the master controller and the branch controller communicate digitally over the communication channel.

7. The commercial refrigeration system of claim 6 wherein the communication channel comprises a wireless communication.

8. The commercial refrigeration system of claim 1 further comprising:

a fixture associated with the evaporator, said fixture storing food to be cooled by the evaporator;

at least one fixture sensor associated with the fixture;

the at least on fixture sensor being constructed and arranged to provide a fixture status signal having a parameter representative of an operating condition associated with the fixture;

a communication channel extending from the master controller;

a fixture controller in digital communication with the master controller over the communication channel; and

the fixture controller being constructed and arranged for receiving the fixture status signal and supplying the fixture status signal to the master controller.

9. The commercial refrigeration system of claim 8 wherein the communication channel comprises a wireless communication channel.

10. The commercial refrigeration system of claim 8 wherein the fixture controller comprises:

a fixture control unit, said fixture control unit communicating digitally with the master controller over the communication channel;

a fixture display unit receiving the fixture status signal and supplying said fixture status signal to the fixture control unit for transmission to the master controller;

the fixture display unit providing a fixture control signal for controlling a control function associated with the fixture;

a switching unit associated with the fixture display unit; and

the switching unit receiving the fixture control signal from the fixture display unit and initiating the fixture control function in response thereto.

11. The commercial refrigeration system of claim 10 wherein the fixture control signal comprises at least one of an anti-sweat control signal controlling an anti-sweat function associated with the fixture, a defrost signal controlling a defrost cycle associated with the fixture, and a light control signal controlling a light associated with the fixture.

12. The commercial refrigeration system of claim 8 wherein the operating condition comprises at least one of a system pressure and a system temperature.

13. The commercial refrigeration system of claim 8 further comprising a fixture data bus extending between the fixture controller and the at least one fixture sensor, and wherein the at least one fixture sensor comprises a plurality of sensors, each of said plurality of sensors providing digital data to the fixture controller over the fixture data bus.

14. The commercial refrigeration system of claim 13 wherein at least one of said plurality of sensors comprises a temperature sensor constructed and arranged to provide a digital representation of a temperature condition associated with the fixture.

15. The commercial refrigeration system of claim 13 wherein the fixture data bus comprises a single twisted pair data bus such that only one data bus is required to facilitate communication between the fixture controller and the plurality of temperature sensors.

16. The commercial refrigeration system of claim 1 further comprising an input/output device in digital communication with the master controller, said input/output device providing access to a system condition parameter associated with the commercial refrigeration system.

17. The commercial refrigeration system of claim 16 further comprising a communication channel constructed and arranged to provide digital communication between the master controller and the input/output device over the communication channel.

18. The commercial refrigeration system of claim 17 wherein the communication channel comprises a wireless communication channel.

20. The commercial refrigeration system of claim 19 further comprising a suction stop switch, said suction stop switch being responsive to a suction control signal from the branch controller to selectively prevent the compressor from drawing refrigerant away from the evaporator such that refrigerant ceases to flow through the evaporator.

21. The commercial refrigeration system of claim 19 further comprising:

a fixture associated with the evaporator, said fixture being constructed and arranged for to hold food to be cooled by the evaporator;

a liquid line control switch, said liquid line control switch being responsive to a refrigeration control signal from the branch controller to prevent the refrigerant from flowing into the evaporator whereby the branch controller selectively cycles the liquid line control switch to affect a temperature of the fixture.

22. The commercial refrigeration system of claim 19 further comprising a defrost control switch, said defrost control switch being responsive to a defrost control signal from the branch controller to enable a defrosting gas to flow through the evaporator for defrosting the evaporator.

23. The commercial refrigeration system of claim 19 further comprising a pressure regulator valve, said pressure regulator valve being responsive to a valve position signal from the branch controller to control a pressure of the refrigerant flowing through the evaporator.

25. The commercial refrigeration system of claim 24 further comprising a subsystem control device having at least two operating states and wherein the determined branch control action comprises generating a separate control signal for driving the subsystem control device to one of the at least two operating states.

26. The commercial refrigeration system of claim 25 wherein the subsystem control device comprises at least one of a suction stop switch, a liquid line switch, a defrost control switch, and a pressure regulator valve.

28. The commercial refrigeration system of claim 27 wherein the communication channel comprises a power and communication line extending from the master controller to the valve controller such that no separate power line must be wired for the branch controller upon installation of the system.

29. The commercial refrigeration system of claim 27 wherein the communication channel comprises a wireless communication channel.

30. The commercial refrigeration system of claim 27 further comprising:

an evaporator having a temperature;

a refrigeration line in fluid communication with the evaporator, said refrigeration line supplying a refrigerant to the evaporator; and

wherein the electronically controlled valve comprises a pressure regulator valve having a plurality of valve positions, said pressure regulator valve being constructed and arranged for controlling the supply of the refrigerant to the evaporator through the refrigeration line such that the temperature of the evaporator is a function of the plurality of valve positions.

19. A commercial refrigeration system suitable for use in a supermarket, said system comprising:

an evaporator having a refrigerant selectively flowing therethrough to cool the evaporator;

a compressor in fluid communication with the evaporator, said compressor drawing refrigerant away from the evaporator;

a master controller selectively supplying a branch control signal;

a power and communication line extending from the master controller; and

a refrigeration branch comprising;

the evaporator;

a refrigeration line for supplying the refrigerant to the evaporator; and

a branch controller for controlling an operation of the refrigeration branch in response to the branch control signal, said master controller and branch controller being constructed and arranged for digital communication over the power and communication line such that no separate power line for the branch controller must be wired upon installation of the system.

24. A commercial refrigeration system suitable for use in a supermarket, said system comprising:

an evaporator having a refrigerant selectively flowing therethrough cooling the evaporator;

a refrigeration line supplying the refrigerant to the evaporator;

the evaporator and refrigeration line comprising a refrigeration branch;

a compressor in fluid communication with the evaporator, said compressor drawing refrigerant away from the evaporator;

a master controller selectively supplying a branch set point signal having a parameter representative of a desired characteristic of the refrigeration branch;

a communication line extending from the master controller; and

a subsystem controller in digital communication with the master controller over the communication line, said subsystem controller receiving the branch set point signal and determining a branch control action in response thereto.

27. A commercial refrigeration system suitable for use in a supermarket, said system comprising:

an electronically controlled valve;

a master controller selectively supplying a valve control signal having a parameter representative of a desired position of the electronically controlled valve;

a valve controller responsive to the valve control signal for selectively supplying a valve drive signal to the electronically controlled valve;

a communication channel extending from the master controller to the valve controller, said master controller supplying the valve control signal to the valve controller over the communication channel; and

wherein the master controller and the valve controller are constructed and arranged such that no separate power line must be wired from the master controller to the valve controller upon installation of the system.

31. A commercial refrigeration system suitable for use in a supermarket, said system comprising:

an electronically controlled valve having a plurality of valve positions;

a master controller selectively supplying a set point signal having a parameter representative of a desired operating condition of the refrigeration system;

a communication channel extending from the master controller;

a valve controller in digital communication with the master controller over the communication channel, said valve controller receiving the set point signal over the communication channel and determining a valve drive signal as a function of the set point signal; and

the valve controller supplying the determined valve drive signal to the electronically controlled valve such that the desired refrigeration system operating condition is substantially achieved.

32. A commercial refrigeration system suitable for use in a supermarket, said system comprising:

at least one fixture;

an evaporator constructed and arranged for cooling the at least one fixture;

a refrigerant supply line supplying a pressurized refrigerant to the evaporator;

a master controller selectively supplying a fixture control signal having a parameter indicative of a desired fixture control action for the at least one fixture;

at least one fixture sensor associated with the at least one fixture;

the at least one fixture sensor being constructed and arranged to provide a fixture status signal having a parameter representative of an operating condition associated with the at least one fixture;

a communication channel extending from the master controller;

a fixture controller in digital communication with the master controller over the communication channel such that no separate power line must be wired from the master controller to the fixture controller upon installation of the system;

the fixture controller receiving the fixture control signal over the communication channel; and

the fixture controller being constructed and arranged for receiving the fixture status signal from the at least one fixture sensor and supplying the fixture status signal to the master controller over the communication channel.

33. The commercial refrigeration system of claim 32 wherein the communication channel comprises a wireless communication channel.

34. The commercial refrigeration system of claim 32 wherein the fixture controller comprises:

a fixture control module, said fixture control module communicating digitally with the master controller over the communication channel;

a fixture display module receiving the fixture status signal from the at least one fixture sensor, said fixture display module supplying the fixture status signal to the control module for transmission to the master controller over the communication channel;

the fixture display module providing a switch control signal for selectively operating a control function associated with the at least one fixture;

a switch associated with the fixture display module; and

the switch receiving the switch control signal from the fixture display module and initiating the control function associated with the at least one fixture in response thereto.

35. The commercial refrigeration system of claim 34 wherein the switch control signal comprises at least one of an anti-sweat control signal selectively controlling an anti- sweat switch associated with the at least one fixture, a defrost signal controlling a defrost switch associated with the at least one fixture, and a light control signal controlling a light switch associated with the at least one fixture.

36. The commercial refrigeration system of claim 34 further comprising a fixture digital data bus extending between the display module and the at least one fixture sensor, wherein the at least one fixture sensor comprises a plurality of temperature sensors, each of said plurality of temperature sensors providing digital temperature data to the display module over the fixture digital data bus.

37. The commercial refrigeration system of claim 36 wherein the fixture data bus comprises a single twisted pair data bus such that only one data bus is required to facilitate communication between the fixture controller and the plurality of temperature sensors.

38. The commercial refrigeration system of claim 32 wherein the fixture controller selectively supplies a pressure control signal having a parameter indicative of a desired pressure setting for the pressurized refrigerant, and wherein the commercial refrigeration system further comprises an evaporator pressure regulator valve responsive to the pressure control signal for controlling a pressure of the pressurized refrigerant.

39. The commercial refrigeration system of claim 38 wherein the fixture controller determines the desired pressure setting as a function of the fixture status signal.

40. The commercial refrigeration system of claim 38 wherein the master controller determines the desired pressure setting as a function of the fixture status signal.

41. The commercial refrigeration system of claim 32 wherein the operating condition comprises a system pressure.

42. The commercial refrigeration system of claim 32 wherein the operating condition comprises a system temperature.

43. A commercial refrigeration system suitable for use in a supermarket, said system comprising:

at least one fixture;

an evaporator constructed and arranged for cooling the at least one fixture;

a refrigerant supply line supplying a pressurized refrigerant to the evaporator;

a master controller;

a fixture controller;

at least one fixture sensor associated with the at least one fixture;

the at least one fixture sensor being constructed and arranged to provide a fixture status signal to the fixture controller, said fixture status signal having a parameter representative of an actual operating condition associated with the at least one fixture;

a communication channel extending from the master controller to the fixture controller;

the master controller selectively supplying a fixture set point signal to the fixture controller over the communication channel, said fixture set point signal having a parameter indicative of a desired operating set point for the at least one fixture; and

the fixture controller being responsive to the fixture set point signal for determining a fixture control action.

44. The commercial refrigeration system of claim 43 further comprising a pressure regulator valve having a plurality of valve positions, wherein the fixture controller selectively supplies a pressure valve control signal to the pressure regulator valve, said pressure valve control signal having a parameter representative of a desired valve position for the pressure regulator valve and wherein the determined fixture control action comprises determining the desired valve position as a function of the fixture set point signal.

45. The commercial refrigeration system of claim 43 further comprising a switching module, the fixture controller selectively providing a switch control signal to the switching module for operating a switch controlled function associated with the at least one fixture wherein the determined fixture control action comprises determining the switch controlled function as a function of the fixture set point signal.

46. The commercial refrigeration system of claim 45 wherein switch control function comprises at least one of controlling an anti-sweat heater associated with the at least one fixture, controlling a defrost cycle associated with the at least one fixture, and controlling a light associated with the at least one fixture.

47. The commercial refrigeration system of claim 43 wherein the communication channel comprises a wireless communication channel such that no wiring is required between the fixture controller and the master controller.

50. The commercial refrigeration system of claim 49 wherein the second communication channel comprises a single twisted wiring pair such that each of the plurality of fixture sensors communicates with the fixture controller over the single twisted wiring pair.

48. A commercial refrigeration system suitable for use in a supermarket, said system comprising:

at least one fixture;

an evaporator constructed and arranged for cooling the at least one fixture;

a refrigerant supply line supplying a pressurized refrigerant to the evaporator;

a master controller;

at least one fixture sensor associated with the at least one fixture;

the at least one fixture sensor being constructed and arranged to provide a fixture status signal having a parameter representative of an operating condition associated with the at least one fixture;

a communication channel extending from the master controller;

a fixture controller in digital communication with the master controller over the communication channel such that no separate power line must be wired from the master controller to the fixture controller upon installation of the system; and

the fixture controller being constructed and arranged for receiving the fixture status signal from the at least one fixture sensor and supplying the fixture status signal to the master controller over the communication channel.

49. A commercial refrigeration system suitable for use in a supermarket, said system comprising:

at least one fixture;

an evaporator constructed and arranged for cooling the at least one fixture;

a refrigerant supply line supplying a pressurized refrigerant to the evaporator;

a master controller;

a plurality fixture sensors associated with the at least one fixture;

the plurality of fixture sensors being constructed and arranged to provide a plurality of fixture status signals, each of said plurality of fixture status signals having a parameter representative of an operating condition associated with the at least one fixture;

a first communication channel extending from the master controller;

a fixture controller in digital communication with the master controller over the communication channel such that no separate power line must be wired from the master controller to the fixture controller upon installation of the system;

a second communication channel extending from the plurality of fixture sensors to the fixture controller; and

the fixture controller being constructed and arranged for receiving the plurality of fixture status signals from the plurality of fixture sensors over the second communication channel and supplying the plurality of fixture status signals to the master controller over the first communication channel.

51. A method of installing a commercial refrigeration control system including a refrigeration subsystem, and a master controller providing a refrigeration set point control command to a subsystem controller controlling the refrigeration subsystem, the method comprising:

installing the master controller at a first location;

installing the subsystem controller at a second location;

supplying a source of electrical power to the master controller; and

installing a power and communication line between the master controller and the subsystem controller whereby the refrigeration set point control command is provided over the power and communication line and no separate power line for the subsystem controller must be wired upon installation of the commercial refrigeration system.

52. The method of claim 51 wherein the subsystem comprises a compressor subsystem and the subsystem controller comprises a compressor operating unit constructed and arranged for monitoring at least one operating parameter of the compressor and determining whether the operating parameter is within a specification limit.

53. The method of claim 51 wherein the subsystem comprises a branch control subsystem controlling a refrigeration branch and the subsystem controller comprises a branch controller constructed and arranged for controlling the flow of a refrigerant flowing in a refrigeration line associated with the refrigeration branch in response to the refrigeration set point control command.

54. The method of claim 51 wherein the subsystem comprises a control valve having a valve position and the subsystem controller comprises a valve controller selectively controlling the position of the control valve in response to the refrigeration set point control command.

55. The method of claim 51 wherein the first location and second location are on a common rack.

57. The method of claim 56 wherein the subsystem comprises a control valve having a valve position and the subsystem controller comprises a valve controller selectively controlling the position of the control valve in response to the refrigeration set point control command.

58. The method of claim 56 wherein the subsystem comprises a condenser subsystem including a fan and the subsystem controller comprises a condenser controller selectively controlling an operation of the fan in response to the refrigeration set point control command.

59. The method of claim 56 wherein the subsystem comprises a display fixture subsystem including a fixture being cooled by an evaporator having a refrigerant flowing therethrough, and wherein the subsystem controller comprises a fixture controller selectively controlling the flow of refrigerant through the evaporator.

56. A method of installing a commercial refrigeration control system including a refrigeration subsystem, and a master controller providing a refrigeration set point control command to a subsystem controller controlling the refrigeration subsystem, the method comprising:

installing the master controller at a first location;

installing the subsystem controller at a second location;

supplying a source of electrical power to the master controller;

installing a communication channel between the master controller and the subsystem controller; and

constructing and arranging said master controller and said subsystem controller for digital communication over the communication channel such that the refrigeration set point control command is provided over the communication channel and no separate power wiring must be wired from the master controller to the subsystem controller upon installation of the commercial refrigeration system.

60. A commercial refrigeration system for use in a food store comprising:

an evaporator constructed and arranged to perform a cooling function;

a compressor in fluid communication with the evaporator for drawing refrigerant vapor from the evaporator;

a condenser in fluid communication with the compressor for receiving refrigerant from the compressor, the condenser being constructed and arranged for removing heat to condense the refrigerant;

an expansion valve in fluid communication with the condenser for receiving liquid refrigerant from the condenser, the expansion valve being constructed and arranged for delivering refrigerant into the evaporator;

a controller for controlling the compressor;

a compressor operating unit associated with the compressor, the operating unit being constructed and arranged for monitoring at least one operating parameter of the compressor and determining whether the operating parameter is within specification;

a power and communication line extending from the controller to the compressor operating unit and providing electrical power for the operating unit;

wherein the controller and compressor operating unit are constructed and arranged for digital communication over the power and communication line such that no separate power line for the operating unit must be wired upon installation of the system;

a fixture for holding food; and

a secondary cooling loop constructed and arranged for cooling the food in the fixture, the evaporator being in heat exchange relationship with the secondary cooling loop for removing heat therefrom.

61. A method of controlling a commercial refrigeration system comprising a master controller selectively supplying a master control signal, at least one subsystem controller selectively supplying a subsystem control signal, a communication channel extending between the master controller and the subsystem controller, a controlled subsystem including a switching device having at least two operating states, said switching device being constructed and arranged to receive the subsystem control signal, said method comprising:

supplying the master control signal from the master controller to the at least one subsystem controller over the communication channel;

receiving the master control signal at the subsystem controller;

determining in the subsystem controller which one of the at least two operating states of the switching device corresponds to the master control signal; and

outputting from the subsystem controller the subsystem control signal in a form that drives the switching device to the desired one of the at least two operating states whereby no separate communication channel exists between the master controller and the switching device.