Co-generator utilizing micro gas turbine engine

• US 20020095939A1
• Filed: 12/18/2000
• Published: 07/25/2002
• Est. Priority Date: 09/14/1998
• Status: Active Grant

• Current Assignee: JetHeat LLC
• Original Assignee: Fairlane Tool Company
• Inventors: Chute, Richard, Gordon, Richard W.
• Granted Patent: US 6,679,433 B2
• Time in Patent Office: Days
• US Class Current: 60/784
• CPC Class Codes: F02C 3/14 characterised by the arrangement of the combustion chamber in the plant combustion chambers per se F23R; F02C3/205 takes precedence
• CPC Class Codes: F02C 6/18 using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants using waste heat as source of energy for refrigeration plants F25B27/02; using the waste heat of a gasturbine for steam generation or in a steam cycle see F01K23/10
• CPC Class Codes: F05D 2250/82 Micromachines
• CPC Class Codes: F24H 2240/02 with combustion engines
• CPC Class Codes: Y02E 20/14 Combined heat and power generation [CHP]

Abstract

The present invention provides a turbo heater which utilizes a gas turbine engine and a heat exchanger assembly. The gas turbine engine is adapted to efficiently operate over a prolonged period of time and at varying power outputs without adverse or detrimental effects to the components thereof. For example, the gas turbine engine includes bearing assemblies and a fuel delivery systems which are uniquely designed for the demands of repeated cycling (i.e. starting and stopping), as well as operation at various power outputs without damage to the gas turbine engine. In addition, the use of exhaust gas from the gas turbine engine eliminates direct impingement of combustion on the heat exchanger element, thereby significantly increasing the durability and life span of the turbo heater.

Claims

1. A turbo heater for providing heated air comprising:

a gas turbine engine including;

an engine housing;

a shaft assembly rotatably supported within said engine housing on a first bearing assembly and a second bearing assembly;

a compressor operably disposed on a first end of said shaft assembly for drawing air into said gas turbine engine and generating compressed air;

a combustor in fluid communication with said compressor such that said compressed air is directed from said compressor into said combustor;

a fuel system for mixing a combustion fuel with said compressed air to form an air-fuel mixture, and for injecting said air-fuel mixture into said combustor such that said air-fuel mixture is ignited and burned in said combustor to generate an exhaust gas; and

a turbine operably disposed on a second end of said shaft assembly for concurrent rotation with said compressor, said combustor being in fluid communication with said turbine such that said exhaust gas are expanded in said turbine, thereby drivingly rotating said shaft assembly;

a heat exchanger assembly including;

a heat exchanger housing; and

a fan operably coupled to said shaft assembly for propelling an ambient air into said heat exchanger housing such that said exhaust gas interacts with said ambient air to generate a heated ambient air which is discharged from said heat exchanger housing.

2. The turbo heater of claim 1 wherein said heat exchanger assembly further comprises a tube bundle disposed in said heat exchanger housing to define a fresh air volume in fluid communication with said fan for propelling said ambient air therethrough, and an exhaust gas volume in fluid communication with said gas turbine engine for passing said exhaust gas therethrough, whereby said tube bundle transfers heat from said exhaust gas to said ambient air for generating said heated ambient air.

3. The turbo heater of claim 2 wherein said heat exchanger assembly further comprises a liquid coil disposed within said heat exchanger housing to define a liquid volume in fluid communication with a liquid pump for pumping a liquid therethrough and an exhaust gas volume in fluid communication with said gas turbine engine for passing said exhaust gas therethrough, whereby said liquid coil transfers heat from said exhaust gas to said liquid for generating a heated liquid.

4. The turbo heater of claim 1 wherein said heat exchanger assembly further comprises a liquid coil disposed within said heat exchanger housing to define a liquid volume in fluid communication with a liquid pump for pumping a liquid therethrough and an exhaust gas volume in fluid communication with said gas turbine engine for passing said exhaust gas therethrough, whereby said liquid coil transfers heat from said exhaust gas to said liquid for generating a heated liquid.

5. The turbo heater of claim 1 wherein said heat exchanger assembly further comprises a catalytic convertor disposed within said heat exchanger housing and in fluid communication with said gas turbine engine for passing said exhaust gas therethrough to generate a catalytically-treated exhaust gas which is exhausted into said heat exchanger housing for mixing with said ambient air.

6. The turbo heater of claim 1 wherein said combustor is an annular combustor concentrically disposed about said shaft assembly between said compressor and said turbine.

7. The turbo heater of claim 6 wherein said tube bundle is generally annularly configured such that said gas turbine engine is at least partially disposed within said annular tube bundle.

8. The turbo heater of claim 1 further comprising a gear reduction assembly having an input shaft operably coupled to said shaft assembly and an output shaft operably coupled to said fan, and a gear set operably coupled between said input shaft and said output shaft to provide a gear ratio therebetween.

9. The turbo heater of claim 8 wherein said gear reduction assembly further comprises a pinion gear disposed on an end of said shaft assembly and a pair of counter-rotating reduction gear sets operably coupled between said pinion gear and said output shaft.

10. The turbo heater of claim 9 wherein said first bearing assembly rotatably supports said pinion gear and is elastically-supported within said engine housing to provide load sharing between said pair of counter-rotating reduction gear sets.

11. The turbo heater of claim 8 further comprising an electrical generator operably coupled to said output shaft of said gear reduction assembly.

12. The turbo heater of claim 11 wherein said electrical generator comprises a first electrical generator for producing electrical power for said turbo heater and a second electrical generator for producing surplus electrical power.

13. The turbo heater of claim 8 further comprising a starter motor operably coupled to said output shaft of said gear reduction assembly for initiating rotation of said shaft assembly for starting said gas turbine engine.

14. The turbo heater of claim 13 further comprising a one-way over-running clutch interdisposed between said output shaft and said starter motor.

15. The turbo heater of claim 13 further comprising a battery electrically connected to said starter motor by a soft start circuit, said soft start circuit including a first circuit having a resistance element interdisposed between said battery and said starter motor for limiting the current drawn from the battery, a second circuit directly connecting said battery to said starter motor, and a controller for selectively switching between said first circuit and said second circuit.

16. The turbo heater of claim 15 wherein said resistance element is disposed in a housing and wherein said combustion fuel is delivered to said housing for heating said combustion fuel prior to injection into said combustor.

17. The turbo heater of claim 1 wherein said fuel system modulates a fuel flow rate to maintain a substantially constant pressure in said combustor, thereby controlling the heat generated by said gas turbine engine.

19. The gas turbine engine of claim 18 wherein said bearing cage has an annular groove formed on a surface thereof and in fluid communication with said plurality of radial holes formed in said bearing cage.

20. The gas turbine engine of claim 18 further comprising a rub ring interdisposed between said inner and outer races adjacent said bearing cage for providing a low friction, dry lubricating material.

21. The gas turbine engine of claim 20 further comprising a graphite rub ring.

22. The gas turbine engine of claim 18 wherein said bearing assembly is elastically supported within said bearing holder such that said shaft assembly is allowed to rotated about a center of mass.

23. The gas turbine engine of claim 22 further comprising a plurality of radial beam springs interdisposed between said outer race and said bearing holder for elastically supporting said bearing assembly.

24. The gas turbine engine of claim 18 further comprising a spring member applying an axial load to said bearing assembly for defining a characteristic natural frequency of said shaft assembly which is greater than an operational frequency of the shaft assembly.

25. The gas turbine engine of claim 24 further comprising a belville spring operably disposed between said bearing holder and said outer bearing race.

26. The gas turbine engine of claim 24 further comprising a compression spring operably disposed between said engine housing and said bearing holder.

27. The gas turbine engine of claim 24 wherein said spring member comprises a compression spring operably disposed between said engine housing and said bearing holder, and a belville spring operably disposed between said bearing holder and said outer bearing race.

29. The gas turbine engine of claim 28 wherein said fuel shield has a plurality of fins formed on a side thereof proximate said scavenger blower and extending radially inwardly.

30. The gas turbine engine of claim 28 wherein said scavenger blower assembly further comprises a pick-up plate disposed in said annulus adjacent said scavenger blower cover.

31. The gas turbine engine of claim 28 further comprising a fuel deflector disposed in said annulus on a side of said bearing assembly opposite said scavenger blower assembly.

32. The gas turbine engine of claim 31 wherein said nozzle hub has at least one radial hole formed therethrough adjacent said fuel deflector for propelling said air-fuel mixture through said bearing assembly.

33. The gas turbine engine of claim 28 wherein said bearing assembly comprises:

an inner bearing race, an outer bearing race and a plurality of bearings interdisposed therebetween; and

a bearing holder disposed in said annulus between said bearing outer race and said nozzle hub, said second fuel passageway formed through said bearing holder.

34. The gas turbine engine of claim 33 wherein said bearing holder has an annular ring formed thereon, said annular ring disposed between said fuel shield and said outer bearing race and extending radially inwardly.

36. The gas turbine engine of claim 35 wherein the longitudinal position of said at least one fuel hole is varied among said plurality of passageways.

37. The gas turbine engine of claim 35 wherein said at least one fuel hole further comprises a first fuel hole and a second fuel hole.

38. The gas turbine engine of claim 37 wherein said first fuel hole is a radial hole disposed along a centerline of said axial bore and said second fuel hole is a semi-radial hole disposed slightly offset from said centerline.

39. The gas turbine engine of claim 38 wherein each of said radial hole and said semi-radial hole are arranged in one of a first longitudinal position and a second longitudinal position to define a pattern such that said pattern is varied among said plurality of passageways.

40. The gas turbine engine of claim 35 wherein said at least one fuel hole further comprises a radial hole disposed along a centerline of said axial bore and a first semi-radial hole disposed slightly offset from said centerline and a second semi-radial hole disposed slightly offset of said centerline on a side opposite said first semi-radial hole.

41. The gas turbine engine of claim 40 wherein each of said radial hole, said first semi-radial hole and said second semi-radial hole are arranged in one of a first longitudinal position, a second longitudinal position and a third longitudinal position to define a pattern such that said pattern is varied among said plurality of passageways.

42. The gas turbine engine of claim 35 wherein each of said plurality of passageways extends axially and radially outwardly from said inner cavity relative to a longitudinal axis of said fuel slinger.

43. The gas turbine engine of claim 35 wherein said fuel slinger further comprises a dam ring disposed in said fuel slinger adjacent said inner cavity.

44. The gas turbine engine of claim 35 further comprising a retainer disposed on said nozzle hub adjacent an outer surface of said fuel slinger opposite said inner cavity.

45. The gas turbine engine of claim 44 wherein said nozzle hub has at least one radial hole formed therethrough adjacent said retainer.

47. The turbo heater of claim 46 wherein said heat exchanger assembly further comprises a tube bundle disposed in said heat exchanger housing to define a fresh air volume in fluid communication with said fan for propelling said ambient air therethrough, and an exhaust gas volume in fluid communication with said gas turbine engine for passing said exhaust gas therethrough, whereby said tube bundle transfers heat from said exhaust gas to said ambient air for generating said heated ambient air.

48. The turbo heater of claim 46 wherein said heat exchanger assembly further comprises a liquid coil disposed within said heat exchanger housing to define a liquid volume in fluid communication with a liquid pump for pumping a liquid therethrough and an exhaust gas volume in fluid communication with said gas turbine engine for passing said exhaust gas therethrough, whereby said liquid coil transfers heat from said exhaust gas to said liquid for generating a heated liquid.

49. The turbo heater of claim 46 wherein said heat exchanger assembly further comprises a catalytic convertor disposed within said heat exchanger housing and in fluid communication with said gas turbine engine for passing said exhaust gas therethrough to generate a catalytically-treated exhaust gas which is exhausted into said heat exchanger housing for mixing with said ambient air.

18. A gas turbine engine for use in a turbo heater comprising:

an engine housing;

a compressor and a turbine disposed on a shaft assembly;

a combustor in fluid communication with said compressor and said turbine; and

a bearing assembly rotatably supporting said shaft assembly within an engine housing, the bearing assembly including;

an inner race formed on the shaft assembly;

an outer race supported within a bearing holder;

a plurality of bearings interdisposed between said inner race and said outer race for rotatably supporting said shaft assembly about a center of rotation; and

a bearing cage interdisposed between said inner race and said outer race for retaining said plurality of bearings, said bearing cage having a plurality of radial holes formed therethrough to provide fluid communication between said inner race and said outer race such that a bearing lubricant issuing from said plurality of radial holes generates a force which centers said bearing cage about said center of rotation.

28. A gas turbine engine for use in a turbo heater comprising:

a turbine nozzle assembly disposed within an engine housing and supporting a nozzle hub;

a shaft assembly disposed within said nozzle hub and defining an annulus therebetween;

a bearing assembly disposed within said annulus and rotatably supporting said shaft assembly in said nozzle hub;

a turbine operably disposed on a first end of said shaft assembly;

a compressor operably disposed on a second end of said shaft assembly;

an annular combustor concentrically disposed about the shaft assembly between the compressor and the turbine;

a fuel feed tube for delivering fuel to said annulus through a first fuel passageway formed in said nozzle hub and a second fuel passageway formed in a portion of said bearing assembly;

a scavenger blower assembly disposed within said annulus, said scavenger blower assembly including a scavenger blower coupled to said shaft assembly for rotation therewith and having a plurality of blades, a scavenger blower cover positioned adjacent to said scavanger blower, and a fuel shield positioned adjacent said second fuel passageway; and

said nozzle hub having a compressed air passageway formed therethrough such that said scavenger blower assembly is operable to direct compressed air from said compressor past said second fuel passageway for mixing fuel with said compressed air to form an air-fuel mixture and passing said air-fuel mixture through said bearing assembly for cooling and lubricating said bearing assembly.

35. A gas turbine engine for use in a turbo heater comprising:

a turbine nozzle assembly disposed within an engine housing and supporting a nozzle hub;

a shaft assembly disposed within said nozzle hub and defining an annulus therebetween;

a bearing assembly disposed within said annulus and rotatably supporting said shaft assembly in said nozzle hub;

a turbine operably disposed on a first end of said shaft assembly;

a compressor operably disposed on a second end of said shaft assembly;

an annular combustor concentrically disposed about the shaft assembly between the compressor and the turbine;

a fuel feed tube for delivering fuel to said annulus;

a fuel slinger coupled to said shaft assembly for rotation therewith, said fuel slinger having an inner cavity and a plurality of passageways formed therein to provide fluid communication between said annulus and said annular combustor, each of said plurality of passageways including an axial bore and at least one fuel hole formed therein such that rotation of said fuel slinger causes fuel to be cylindrically distributed into said combustor.

46. A turbo heater for providing heated air comprising:

an engine housing;

a turbine nozzle assembly disposed within said engine housing and supporting a nozzle hub;

a shaft assembly disposed within said nozzle hub and defining an annulus therebetween;

a rear bearing assembly disposed within said annulus and rotatably supporting said shaft assembly in said nozzle hub, the rear bearing assembly including an inner race formed on the shaft assembly, an outer race supported within a bearing holder, a plurality of bearings interdisposed between said inner and outer races for rotatably supporting said shaft assembly about a center of rotation, and a bearing cage interdisposed between said inner and outer races and retaining said plurality of bearings, said bearing cage having a plurality of radial holes formed therethrough for providing fluid communication between said inner race and said outer race;

a front bearing assembly disposed within said engine housing and rotatably supporting said shaft assembly;

a compressor operably disposed on a first end of said shaft assembly for drawing air into said engine housing and generating compressed air;

an annular combustor concentrically disposed about the shaft assembly adjacent said compressor;

a fuel delivery system including a fuel feed tube for delivering a fuel to said annulus through a first fuel passageway formed in said nozzle hub and a second fuel passageway formed in said bearing holder, a scavenger blower assembly disposed within said annulus, and a fuel slinger coupled to said shaft assembly for rotation therewith, said nozzle hub having a compressed air passageway formed therethrough, wherein said scavenger blower assembly is operable to direct compressed air from said compressor past said second fuel passageway for mixing said fuel with said compressed air to form an air-fuel mixture, said air-fuel mixture passing through said bearing cage holes for centering said bearing cage about said center of rotation, through said bearing assembly for cooling and lubricating said bearing assembly and into said fuel slinger such that said air-fuel mixture is injected into said annular combustor and combusted to form a combusted gas;

a turbine operably disposed on a second end of said shaft assembly for concurrent rotation with said compressor, said combusted gas being expanded in said turbine, thereby drivingly rotating said shaft assembly;

a gear reduction assembly including an input shaft operably coupled to said shaft assembly, an output shaft, and a gear set operably coupled between said input shaft and said output shaft;

an electrical generator operably coupled to said output shaft of said gear reduction assembly;

a starter assembly having a starter motor operably coupled to said output shaft of said gear reduction assembly through a clutch member to initiate rotation of said shaft assembly for starting said gas turbine engine;

a heat exchanger assembly including a housing and a heat exchanger element in fluid communication with said gas turbine engine; and

a fan operably coupled to said output shaft for propelling an ambient air into said heat exchanger housing such that said exhaust gas interacts with said ambient air to generate a heated ambient air which is discharged from said heat exchanger housing.