Systems and methods for providing cooling in compressed air storage power supply systems

• US 20060059937A1
• Filed: 09/17/2004
• Published: 03/23/2006
• Est. Priority Date: 09/17/2004
• Status: Abandoned Application

• Current Assignee: Active Power Incorporated
• Original Assignee: Active Power Incorporated
• Inventors: Perkins, David E., Pinkerton, Joseph F., Radke, Robert E., Andrews, James A., Logan, Scott D.
• Application Number:
  US10/943,291
• Publication Number:
  US 20060059937A1
• Time in Patent Office: Days
• US Class Current: 62/259.200
• CPC Class Codes: F02C 6/16 for storing compressed air
• CPC Class Codes: F02C 7/18 the medium being gaseous, e.g. air F02C7/125 takes precedence
• CPC Class Codes: F05D 2260/234 of the generator by compressor inlet air
• CPC Class Codes: H02J 15/006 in the form of pneumatic energy, e.g. compressed air energy storage [CAES] accumulators for supplying fluid under pressure F15B1/04
• CPC Class Codes: H02K 11/05 Rectifiers associated with casings, enclosures or brackets
• CPC Class Codes: H02K 5/20 with channels or ducts for flow of cooling medium
• CPC Class Codes: H02K 5/207 with openings in the casing specially adapted for ambient air
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids

Abstract

A system and method for cooling electrical machines (e.g., generators), sub-systems (e.g., power electronics), and components (e.g., bearings) in an electrical generation system such as a compressed air storage (CAS) energy system or a thermal and compressed air storage (TACAS) energy system is provided. Cooling is derived from the thermal expansion of a compressed gas, which may be the same gas used to drive a turbine-generator of CAS or TACAS energy system.

Claims

1. A method for cooling components and/or subsystems of an electrical generation system, comprising:

providing a source of compressed gas;

decompressing said compressed gas, the decompression of which causes the temperature of said compressed gas to drop to a predetermined temperature; and

cooling at least one component and/or subsystem with said decompressed gas.

2. The method defined in claim 1, further comprising:

regulating said decompressing such that said compressed gas is decompressed to a predetermined pressure.

3. The method defined in claim 1, further comprising:

using said compressed gas to generate electrical power.

4. The method defined in claim 1, further comprising:

maintaining the temperature of said at least one component and/or subsystem at a predetermined temperature with said decompressed gas.

5. The method defined in claim 1, wherein said cooling comprises routing said decompressed gas to, or proximal to, an electrical machine.

6. The method defined in claim 1, wherein said cooling comprises routing said decompressed gas to, or proximal to, at least one bearing that supports a rotor of a turbine-generator.

7. The method defined in claim 1, wherein said cooling comprises routing said decompressed gas to, or proximal to, power electronics.

8. The method defined in claim 1, further comprising:

routing said decompressed gas from said at least one component and/or subsystem to at least one other component and/or subsystem.

9. The method defined in claim 1, further comprising:

distributing heat retained by said decompressed gas while cooling said at least one component and/or subsystem to another component and/or subsystem.

10. A system for cooling components and/or subsystems of an electrical generation system, comprising:

a source of compressed gas;

a valve coupled to said source of compressed gas and operative to control the decompression of said compressed gas, the decompression of which causes the temperature of said compressed gas to drop to a predetermined temperature; and

at least one component and/or subsystem connected downstream of said valve and is cooled by said decompressed gas.

11. The system defined in claim 10, wherein said valve is a pressure regulator.

12. The system defined in claim 10, wherein said at least one component and/or subsystem comprises an electrical machine.

13. The system defined in claim 10, wherein said at least one component and/or subsystem comprises at least one bearing.

14. The system defined in claim 10, wherein said at least one component and/or subsystem comprises power electronics.

15. The system defined in claim 10, further comprising:

a housing that receives said decompressed gas, said housing constructed to route said decompressed gas to, or proximal to, said at least one component and/or subsystem.

16. The system defined in claim 10, further comprising:

a turbine-generator connected to receive decompressed gas used to cool said at least one component and/or subsystem, said turbine-generator being driven by said decompressed gas to generate power.

17. The system defined in claim 16, wherein said turbine generator if further connected to receive said decompressed gas substantially directly from said valve.

18. The system defined in claim 16, further comprising:

a thermal storage unit connected to receive decompressed gas used to cool said at least one component and/or system, said thermal storage unit heats said decompressed gas to a predetermined temperature, and said thermal storage unit is connected to provide said heated decompressed gas to said turbine-generator.

19. A method for cooling equipment in a backup energy system, comprising:

providing a source of compressed gas;

selectively decompressing said compressed gas, the decompression of which causes the temperature of said compressed gas to drop to a predetermined temperature; and

routing said decompressed gas to, or proximal to, an electrical machine to remove heat from said electrical machine while said backup energy system is operating in an emergency mode of operation.

20. The method defined in claim 19 further comprising:

maintaining an operating temperature of said electrical machine at a desired operating temperature.

21. The method defined in claim 19, wherein said desired operating temperature is a sub-ambient temperature.

22. The method defined in claim 19 further comprising:

driving a turbine with said selectively decompressed gas; and

powering said electrical machine when said turbine is being driven.

23. The method defined in claim 19 further comprising:

routing a first portion of said decompressed gas to a turbine;

routing a second portion of said decompressed gas to, or proximal to, said electrical machine; and

re-routing said second portion to said turbine after said second portion has been routed to said electrical machine.

24. The method defined in claim 23, wherein said re-routing comprises heating said second portion prior to providing said re-routed second portion to said turbine.

25. The method defined in claim 24, wherein said heating comprises recovering heat from said electrical machine.

26. The method defined in claim 25, wherein said heating is performed by an exhaustless heater.

27. The method according to claim 23 further comprising:

routing a third portion of said decompressed gas directly to at least one bearing.

28. A method for providing backup power to a critical load in the event of a disturbance in the supply of power from a primary power source, comprising:

providing a compressed gas;

driving a turbine with said compressed gas;

powering an electrical machine with said turbine to provide backup power; and

cooling at least said electrical machine with said compressed gas.

29. The method defined in claim 28, wherein said cooling comprises:

decompressing said compressed gas to provide a cool gas; and

routing said cool gas to, or proximal to, said electrical machine.

30. The method defined in claim 29, wherein said routing comprises:

providing said cool gas to a stator housing of said electrical machine.

31. The method defined in claim 29, wherein said routing comprises:

providing said cool gas to a bearing that supports a shaft being driven by said turbine.

32. The method defined in claim 28, wherein said cooling comprises maintaining said electrical machine at a desired operating temperature.

33. A method for maintaining a desired operating temperature of an electrical generator being driven by a turbine in an electrical generation system, comprising:

providing a compressed gas;

regulating the expansion of said compressed gas, the expansion of which causes said compressed gas to cool;

routing said cool gas to a stator housing of said electrical generator; and

removing heat from said electrical generator as said cool gas passes through said stator housing.

34. The method defined in claim 33 further comprising:

driving a turbine with said compressed gas; and

powering said electrical machine with said turbine to provide power.

35. A backup energy system, comprising:

a source of compressed gas;

a valve connected to said source and operative to decompress said compressed gas, the decompression of which causes the temperature of said compressed gas to drop to a predetermined temperature; and

a path connected to said valve that routes said decompressed gas to, or proximal to, an electrical machine to remove heat from said electrical machine while said backup energy system is operating in an emergency mode of operation.

36. The system defined in claim 35, further comprising:

a turbine connected to the portion of said path exiting said electrical machine, said turbine powers said electrical machine as said decompressed gas being routed through said path drives the turbine blades of said turbine.

37. The system defined in claim 36, wherein said path is a first path and said turbine comprises at least one bearing for supporting a shaft, said system further comprising:

a second path connected to said valve that routes said decompressed gas to, or proximal to, said at least one bearing.

38. The system defined in claim 35, further comprising:

an exhaustless heater connected to the portion of said path exiting said electrical machine, said heater heats said decompressed gas to a predetermined temperature; and

a turbine connected to the output of said exhaustless heater, said turbine powers said electrical machine as said heated decompressed gas drives the turbine blades of said turbine.

39. The system defined in claim 38, wherein said exhaustless heater is a thermal storage unit.

40. The system defined in claim 35, further comprising:

a stator housing connected to said path and to said electrical machine, said stator housing enables said decompressed gas to absorb heat generated by said electrical machine.

41. The system defined in claim 35, wherein said path is a first path and said electrical machine comprises at least one bearing for supporting a shaft, said system further comprising:

a second path connected to said valve and routes said decompressed gas to, or proximal to, said at least one bearing to remove heat from said at least one bearing while said backup energy system is operating in an emergency mode of operation.

42. The system defined in claim 35, wherein said path is a first path, said first path routes said decompressed gas to said electrical machine, a thermal storage unit, and to a turbine.

43. The system defined in claim 42, further comprising a second path connected to said valve that routes said decompressed gas to said turbine.

44. The system defined in claim 35, wherein said predetermined temperature is a temperature lower than the temperature of said compressed gas stored in said air source.

45. The system defined in claim 35, wherein said compressed gas is compressed air.

46. The system defined in claim 35, wherein said valve is a pressure regulator.

47. A system for maintaining a desired operating temperature of an electrical generator being driven by a turbine in a compressed air storage system, comprising:

a source of compressed gas;

a valve that regulates the expansion of said compressed gas, the expansion of which causes said compressed gas to cool; and

a stator housing mounted to said electrical machine and connected to receive said cool gas from said valve, said stator housing constructed to enable said cool gas to remove heat from said electrical generator as said cool gas passes through said stator housing.

48. The system defined in claim 47, further comprising:

an exhaustless heater connected to receive said cool gas exiting said stator housing, said heater heats said cool gas to a predetermined temperature, wherein said turbine is connected to receive said heated gas from said heater.

49. The system defined in claim 47, further comprising:

at least one bearing housing connected to receive said cool gas from said valve, said at least one bearing housing constructed to enable said cool gas to remove heat generated by a bearing housed within said bearing housing.

50. The system defined in claim 48, wherein said at least one bearing housing is coupled to, or within, said electrical machine.

51. The system defined in claim 48, wherein said at least one bearing housing is coupled to, or within, said turbine.

52. The system defined in claim 48, wherein said gas exiting said at least one bearing housing is combined with said gas exiting said stator housing.

53. The system defined in claim 48, wherein said valve is a first valve, said system further comprising:

a second valve connected to said first valve and operative to reduce the pressure of said cool gas provided to said at least one bearing housing, and wherein said gas exiting said at least one bearing is vented to atmosphere.

54. The system defined in claim 47, further comprising control circuitry operative to control the operation of said valve.

55. A stator housing, comprising:

a stator jacket having an inner diameter, an outer diameter, and an annular groove of a predetermined width and depth; and

a stator jacket sleeve having an inlet port and an outlet port and constructed to slide over said stator jacket to provide an airtight seal over said annular groove such that when said sleeve is slid in position over said jacket, an annular channel is formed to permit a fluid to flow from said inlet port through said annular channel to said outlet port.

56. The housing defined in claim 55, wherein said stator jacket sleeve has an inner diameter that is greater than said outer diameter of said stator jacket but only to an extent that yields said airtight seal.

57. The housing defined in claim 55, wherein said stator jacket comprises a plurality of o-ring grooves.

58. The housing defined in claim 57 further comprising an o-ring positioned in each of said plurality of o-ring grooves.

59. The housing defined in claim 55, wherein said inner diameter of said jacket is such that said jacket slides over the stator of an electrical machine.

60. A stator housing, comprising:

an inlet port;

an outlet port;

at least one annular channel that is connected to said inlet and outlet ports to permit flow of fluid from said inlet port through said at least one annular channel to said outlet port; and

a pressure sleeve that is fixed to an inner diameter of said housing to provide pressure containment of fluid flowing through said at least one annular channel.

61. The housing defined in claim 60, wherein said at least one annular channel comprises at least two annular channels, said housing further comprising:

a first axial flow channel connected to said input port and to said at least two annular channels; and

a second axial flow channel connected to said output port and to said at least two annular channels.

62. The housing defined in claim 60, wherein said stator housing is cast.

63. The housing defined in claim 60, wherein said stator housing is machined.

64. An electrical generator assembly, comprising:

a generator comprising a stator having an outer diameter; and

a stator housing having an inner diameter that enables said housing to fit flush against the outer diameter of said stator, said stator housing comprising;

an inlet port;

an outlet port;

at least one annular channel connected to said inlet and outlet ports to permit flow of fluid from said inlet port through said at least one annular channel to said outlet port; and

a pressure sleeve that forms said inner diameter of said housing and provides pressure containment of fluid flowing in said at least one annular channel.

65. The assembly defined in claim 64, wherein said pressure sleeve fits flush against said outer diameter of said stator.

66. The assembly defined in claim 64, wherein said stator fits flush against said pressure sleeve.