Heat engine

• US 7,062,913 B2
• Filed: 12/15/2000
• Issued: 06/20/2006
• Est. Priority Date: 12/17/1999
• Status: Expired due to Term

• Current Assignee: Ohio State Innovation Foundation (Ohio State University)
• Original Assignee: Ohio State University
• Inventors: Christensen, Richard N., Cao, Jiming, Henkel, E. Thomas
• Primary Examiner(s): Nguyen, Hoang
• Application Number:
  US10/168,169
• Publication Number:
  US 20030000213A1
• Time in Patent Office: 2,013 Days
• Field of Search: 606/53, 606/79, 606/80, 606/81, 606/51, 606/71, 606/18, 110/245, 110/345
• US Class Current: 60/651
• CPC Class Codes: F01K 25/08 using special vapours
• CPC Class Codes: F02C 1/05 characterised by the type or source of heat, e.g. using nuclear or solar energy
• 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: F25B 15/008 with multi-stage operation F25B15/006 takes precedence
• CPC Class Codes: F25B 15/02 without inert gas F25B15/004, F25B15/006, F25B15/008, F25B15/12, F25B15/14, F25B15/16 take precedence
• CPC Class Codes: F25B 15/04 the refrigerant being ammonia evaporated from aqueous solution F25B15/025 takes precedence
• CPC Class Codes: F25B 15/06 the refrigerant being water vapour evaporated from a salt solution, e.g. lithium bromide F25B15/025 takes precedence
• CPC Class Codes: F25B 2315/002 Generator absorber heat exchanger [GAX]
• CPC Class Codes: F25B 2333/003 the generator or boiler is heated by combustion gas
• CPC Class Codes: F25B 27/00 Machines, plants or systems, using particular sources of energy F25B30/06 takes precedence
• CPC Class Codes: F25B 27/02 using waste heat, e.g. from internal-combustion engines
• CPC Class Codes: F25B 33/00 Boilers; Analysers; Rectifiers boiler-absorbers F25B35/00
• CPC Class Codes: F25B 6/04 arranged in series
• CPC Class Codes: F28F 1/08 Tubular elements crimped or corrugated in longitudinal section
• CPC Class Codes: F28F 9/22 Arrangements for directing heat-exchange media into successive compartments, e.g. arrangements of guide plates
• CPC Class Codes: Y02A 30/274 using waste energy, e.g. from internal combustion engine
• CPC Class Codes: Y02B 30/625 combined with heat or power generation [CHP], e.g. trigeneration
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

A heat engine (10) achieves operational efficiencies by: 1) recovering waste heat from heat engine expander (14) to preheat heat-engine working fluid, 2) using super-heated working fluid from compressor (402) to pre-heat heat-engine working fluid, and 3) using reject heat from condenser (93) and absorber (95) to heat the heat-engine boiler (12). A dual heat-exchange generator (72) affords continuous operation by using gas-fired heat exchanger (212) to heat generator (72) when intermittent heat source (40), e.g., solar, is incapable of heating generator (72). The combination of heat engine (10) and absorption and compression heat transfer devices (60, 410) allows use of low-temperature heat sources such as solar, bio-mass, and waste heat to provide refrigeration, heating, work output including pumping and heating of subterranean water and electrical generation.

Claims

1. A heat engine comprising:

a) a boiler having an inlet and an outlet and connected to receive a working fluid in a liquid state and vaporizing said working fluid to a vapor on input of heat from a boiler, heat-source input heat exchanger;

b) a positive displacement rotating expander with an inlet and outlet and adapted for receiving and expanding said vapor from said boiler outlet at high pressure to produce a work output and providing said vapor at low pressure at said outlet;

c) a condenser having an inlet for receiving said vapor from said expander outlet and condensing said vapor to said working fluid liquid;

d) a pump with an inlet and outlet for taking said working fluid liquid from said condenser at low pressure and providing said working fluid to said boiler inlet at high pressure; and

e) at least one of the following;

1) a heat-transfer device for recovering waste heat from said heat engine and using said heat to improve said heat engine efficiency and wherein said heat-transfer device comprises one or more heat exchangers whereby at least one of the following heat transfers occurs;

a) heat from said working fluid leaving said expander outlet is exchanged to said working fluid to preheat said working fluid prior to entering said boiler; and

b) work heat from said pump is exchanged to said working fluid to preheat said working fluid prior to entering said boiler;

2) a compression heat-transfer device comprising the following interconnected components;

a) an evaporator;

b) a compression device condenser;

c) a throttling valve; and

d) a compressor for compressing a compression device working fluid circulating through said interconnected components of said compression heat-transfer device; and

e) said compression heat-transfer device providing heat to said working fluid of said heat engine; and

3) an absorption heat transfer device comprising the following interconnected absorption, heat-transfer device components;

a) a generator,

b) an absorber;

c) a condenser;

4) an evaporator; and

e) a working solution comprising an absorbent and refrigerant; and

f) said absorption heat transfer device transferring heat to or from said working fluid of said heat engine.

2. The heat engine according to claim 1 wherein said heat-transfer device is one or more heat exchangers whereby at least one of the following heat transfers occurs:

a) heat from said working fluid leaving said expander outlet is exchanged to said working fluid to preheat said working fluid prior to entering said boiler; and

b) work heat from said pump is exchanged to said working fluid to preheat said working fluid prior to entering said boiler.

3. The heat engine according to claim 1 with said compression heat-transfer device comprising the following interconnected components:

a) an evaporator;

b) a compression device condenser;

c) a throttling valve; and

d) a compressor for compressing a compression device working fluid circulating through said interconnected components of said compression heat-transfer device; and

e) a common shaft driven by said heat engine expander and driving said compression heat-transfer device compressor; and

f) wherein at least one of the following heat transfers occurs;

1) a compressor heat exchanger transfers work heat from said compressor to said heat-engine working fluid coming from said heat-engine condenser; and

2) a pre-heater heat exchanger containing super-heated working fluid from said compressor transfers heat to said heat-engine working fluid to pre-heat said heat-engine working fluid prior to entering said boiler.

4. The heat engine according to claim 3 further comprising:

a) a heat-source loop with interconnected heat-source loop components comprising;

1) a heat-source input heat exchanger for receiving heat;

2) a heat-source loop pump circulating a heat-transfer fluid through said heat-source loop components;

3) said boiler, heat-source input heat exchanger for transferring heat to said boiler; and

4) a compression heat-transfer device evaporator heat exchanger for transferring heat to said compression heat-transfer device evaporator; and

b) a heating loop with interconnected heating-loop components comprising;

1) a heating-loop pump circulating a heat-transfer fluid through said heating-loop components;

2) a heat-engine condenser heat exchanger for receiving heat from said heat-engine condenser;

3) a compression heat-transfer device condenser heat exchanger for receiving heat from said compression heat-transfer device condenser; and

4) a load heat exchanger for transferring heat to a load to be heated.

5. The heat engine according to claim 3 further comprising:

a) a heat-source loop with interconnected heat-source loop components comprising;

1) a heat-source input heat exchanger for receiving heat;

2) a heat-source loop pump circulating a heat-transfer fluid through said heat-source loop components; and

3) said boiler, heat-source input heat exchanger for transferring heat to said boiler;

b) a heat-removal loop with interconnected heat-removal loop components comprising;

1) a heat-removal loop pump circulating a heat-transfer fluid through said heating loop components;

2) a heat-engine condenser heat exchanger for receiving heat from said heat-engine condenser;

3) a compression heat-transfer device condenser heat exchanger for receiving heat from said compression heat-transfer device condenser; and

4) a heat exchanger for dissipating heat to the environment; and

c) a cooling loop with interconnected cooling-loop components comprising;

1) an evaporator heat exchanger for transferring heat to said evaporator;

2) a cooling heat-exchanger for receiving heat from a load to be cooled; and

3) a cooling-loop pump for circulating a heat-transfer fluid through said cooling-loop components.

6. The heat engine according to claim 1 with:

a) said absorption heat transfer device comprising the following interconnected absorption, heat-transfer device components;

1) a generator,

2) an absorber;

3) a condenser;

4) an evaporator; and

5) a working solution comprising an absorbent and refrigerant; and

b) wherein heat is provided to said boiler, heat-source input heat exchanger from at least one of the following;

1) said absorber;

2) said absorption heat-transfer device condenser;

3) said generator; and

4) heat available for input to said generator.

7. The heat engine according to claim 6 wherein said boiler is one or more heat exchangers located in at least one of said absorber and said absorption heat-transfer device condenser.

8. The heat engine according to claim 6 wherein a portion of said generator and a portion of said absorber are in heat-exchange relation with each other.

9. The heat engine according to claim 6 with said generator comprising a generator, heat-source input heat exchanger connected with said boiler, heat-source input heat exchanger for selected delivery of heat to:

1) said boiler;

     2) said generator; and

     3) both said boiler and said generator.

10. The heat engine according to claim 6 further comprising:

a) a high-temperature heat-exchange loop with interconnected high-temperature loop components comprising;

1) a heat-source input heat exchanger for receiving heat;

2) a high-temperature pump circulating a heat-transfer medium in said high-temperature loop;

3) said boiler, heat-source input heat exchanger for transferring heat to said boiler;

4) a high-temperature loop heat exchanger;

b) an intermediate-temperature heat exchange loop with interconnected intermediate temperature loop components comprising;

1) a heat-engine condenser heat exchanger for receiving heat from said heat-engine condenser;

2) a recuperator;

3) a first intermediate-temperature loop heat exchanger for receiving heat from said high-temperature loop heat exchanger;

4) a generator, heat source input heat exchanger for transferring heat to said generator;

5) a recuperator heat exchanger for transferring heat to said recuperator;

6) a second intermediate-temperature loop heat exchanger; and

7) an intermediate-temperature pump for circulating an intermediate heat-transfer fluid in said intermediate-temperature heat exchange loop;

c) a low-temperature heat-exchange loop with interconnected low-temperature loop components comprising;

1) an absorption heat-transfer device condenser heat exchanger for receiving heat from said absorption heat-transfer device condenser;

2) an absorber heat exchanger for receiving heat from said absorber;

3) a low-temperature loop heat exchanger for receiving heat from said second intermediate-temperature loop heat exchanger;

4) a heat-sink heat exchanger for transferring heat to a heat sink; and

5) a low-temperature pump for circulating a low-temperature heat transfer fluid in said low temperature loop.

11. The heat engine according to claim 6 comprising:

a) a high-temperature heat-exchange loop with interconnected high-temperature loop components comprising;

1) a heat-source input heat exchanger for receiving heat;

2) a first generator, heat-source input heat exchanger transferring heat to said generator; and

3) a high-temperature pump circulating a heat-transfer medium in said high-temperature loop;

b) a second generator, heat-source input heat exchanger transferring heat to said generator; and

c) a low temperature heat-exchange loop comprising the following interconnected components;

1) an absorption heat-transfer device condenser heat exchanger receiving heat from said absorption heat-transfer device condenser;

2) an absorber heat exchanger receiving heat from said absorber;

3) said boiler, heat-source input heat exchanger transferring heat to said boiler;

4) a low-temperature pump for circulating a heat-transfer medium in said low-temperature loop.

12. The heat engine according to claim 6 comprising:

a) a high-temperature heat-exchange loop with interconnected high-temperature loop components comprising;

1) a heat-source input heat exchanger for receiving heat;

2) a first generator, heat-source input heat exchanger transferring heat to said generator;

3) said boiler, heat-source input heat exchanger transferring heat to said boiler; and

4) a high-temperature pump circulating a heat-transfer medium in said high-temperature loop; and

b) a second generator, heat-source input heat exchanger transferring heat to said generator.

13. The heat engine according to claim 12 wherein said interconnected high-temperature loop components further comprise a heat-engine condenser heat exchanger for receiving heat from said heat-engine condenser.

14. The heat engine according to claim 6 with said generator comprising:

a) a substantially first vertical surface separating a first fluid space from a second fluid space;

b) a substantially second vertical surface separating said first fluid space from a third fluid space;

c) said first fluid space containing;

1) said working solution in downward flow; and

2) said refrigerant in vapor form at least partially in upward flow within said downward flowing working solution;

3) substantially horizontal, spaced-apart, fluid distribution plates, each plate having an aperture formed therein;

4) said aperture providing;

(a) downward passage and distribution of said downward flowing working solution; and

(b) upward passage and distribution of said upward flowing refrigerant vapor;

d) said second fluid space containing a first heat-transfer fluid heating said first fluid space; and

e) said third fluid space containing a second heat-transfer fluid transferring heat with respect to said first fluid space.

15. The heat engine according to claim 14 wherein said vertical surface separating said first fluid space from said second fluid space is an open inner cylinder with the center of said cylinder forming said second fluid space and said first fluid space is an annular space formed by an enclosure comprising:

a) an center portion of said inner cylinder outer surface;

b) a center portion of an outer cylinder inner surface;

c) an upper separation plate; and

d) a lower separation plate.

16. The heat engine according to claim 15 wherein said aperture of each successive spaced-apart fluid distribution plate is located on opposite sides of said annular first fluid space.

17. The heat engine according to claim 14 with said vertical surface separating said first fluid space from said third fluid space comprising a plurality of vertical tubes.

18. The heat engine according to claim 17 wherein said third fluid space formed by interiors of said plurality of vertical tubes opens to:

a) an annular upper manifold comprising;

1) an upper portion of an outer cylinder;

2) an upper portion of an inner cylinder;

3) a top; and

4) an upper separation plate; and

5) a first fluid passage; and

b) an annular lower manifold comprising;

1) a lower portion of said outer cylinder;

2) a lower portion of said inner cylinder;

3) a lower separation plate;

4) a bottom; and

5) a second fluid passage.

19. The heat engine according to claim 1 further comprising a water pump driven by said expander work output and used to pump ground water.

20. The heat engine according to claim 1 further comprising a condenser heat exchanger for exchanging heat from said condenser to ground water.

21. The heat engine according to claim 4 further comprising a heat source for providing heat to said heat-source input heat exchanger.

22. The heat engine according to claim 21 further comprising a backup heat source for said heat source.

23. The heat engine according to claim 22 wherein said heat source or said backup heat source is selected as one of the following:

a) solar heat, b) geothermal heat, c) industrial waste heat, d) biomass combustion heat, e) fossil fuel combustion device heat, and f) fossil fuel combustion exhaust heat.

24. The heat engine according to claim 11 further comprising a second heat source for providing heat to said second generator heat-source input heat exchanger wherein said second heat source is a gas burner.

25. The heat engine according to claim 24 wherein said second generator heat source input heat exchanger is a annular tube with an interior side contacting hot combustion products from said gas burner and an exterior side contacting said generator.

26. The heat engine according to claim 11 wherein both said first generator heat-source input heat exchanger and said second generator heat-source input heat exchanger simultaneously transfer heat to said generator.

27. The heat engine according to claim 11 wherein said heat-source input heat exchanger is inoperative and said generator is heated by said second generator heat-source input heat exchanger, said generator transferring heat to said heat transfer medium in said first generator heat-source input heat exchanger which in turn transfers heat to said boiler heat-source input heat exchanger thereby heating said boiler.

28. The heat engine according to claim 1 wherein said working fluid is an organic refrigerant with operating pressures and temperatures lower than operating pressures and temperatures of a water working fluid.

29. The heat engine according to claim 1 wherein said expander is a scroll expander or a gerotor expander.

30. The heat engine according to claim 3 wherein said working fluid circulating in said heat engine components is the same as the working fluid circulating in said compression heat-transfer device components.

31. The heat engine according to claim 30 wherein said working fluid in said heat-engine components and in said compression heat-transfer device components is ammonia.

32. The heat engine according to claim 1 wherein at least one working fluid pump, working solution pump or heat-exchange medium circulating pump is driven by said expander work output.

66. The heat engine according to claim 2 further comprising a water pump driven by said expander work output and used to pump ground water.

67. The heat engine according to claim 6 further comprising a water pump driven by said expander work output and used to pump ground water.

68. The heat engine according to claim 8 further comprising a water pump driven by said expander work output and used to pump ground water.

69. The heat engine according to claim 2 further comprising a condenser heat exchanger for exchanging heat from said condenser to ground water.

70. The heat engine according to claim 6 further comprising a condenser heat exchanger for exchanging heat from said condenser to ground water.

71. The heat engine according to claim 8 further comprising a condenser heat exchanger for exchanging heat from said condenser to ground water.

72. The heat engine according to claim 5 further comprising a heat source for providing heat to said heat-source input heat exchanger.

73. The heat engine according to claim 72 further comprising a backup heat source for said heat source.

74. The heat engine according to claim 6 further comprising a heat source for providing heat to said heat-source input heat exchanger.

75. The heat engine according to claim 74 further comprising a backup heat source for said heat source.

76. The heat engine according to claim 8 further comprising a heat source for providing heat to said heat-source input heat exchanger.

77. The heat engine according to claim 76 further comprising a backup heat source for said heat source.

78. The heat engine according to claim 10 further comprising a heat source for providing heat to said heat-source input heat exchanger.

79. The heat engine according to claim 78 further comprising a backup heat source for said heat source.

80. The heat engine according to claim 11 further comprising a heat source for providing heat to said heat-source input heat exchanger.

81. The heat engine according to claim 80 further comprising a backup heat source for said heat source.

82. The heat engine according to claim 12 further comprising a second heat source for providing heat to said second generator heat-source input heat exchanger wherein said second heat source is a gas burner.

83. The heat engine according to claim 82 wherein said second generator heat source input heat exchanger is a annular tube with an interior side contacting hot combustion products from said gas burner and an exterior side contacting said generator.

84. The heat engine according to claim 13 further comprising a second heat source for providing heat to said second generator heat-source input heat exchanger wherein said second heat source is a gas burner.

85. The heat engine according to claim 12 wherein both said first generator heat-source input heat exchanger and said second generator heat-source input heat exchanger simultaneously transfer heat to said generator.

86. The heat engine according to claim 12 wherein said heat-source input heat exchanger is inoperative and said generator is heated by said second generator heat-source input heat exchanger, said generator transferring heat to said heat transfer medium in said first generator heat-source input heat exchanger which in turn transfers heat to said boiler heat-source input heat exchanger thereby heating said boiler.

87. The heat engine according to claim 2 wherein said working fluid is an organic refrigerant with operating pressures and temperatures lower than operating pressures and temperatures of a water working fluid.

88. The heat engine according to claim 3 herein said working fluid is an organic refrigerant with operating pressures and temperatures lower than operating pressures and temperatures of a water working fluid.

89. The heat engine according to claim 6 wherein said working fluid is an organic refrigerant with operating pressures and temperatures lower than operating pressures and temperatures of a water working fluid.

90. The heat engine according to claim 2 wherein said expander is a scroll expander or a gerotor expander.

91. The heat engine according to claim 3 wherein said expander is a scroll expander or a gerotor expander.

92. The heat engine according to claim 6 wherein said expander is a scroll expander or a gerotor expander.

93. The heat engine according to claim 4 wherein said working fluid circulating in said heat engine components is the same as the working fluid circulating in said compression heat-transfer device components.

94. The heat engine according to claim 93 wherein said working fluid in said heat-engine components and in said compression heat-transfer device components is ammonia.

95. The heat engine according to claim 5 wherein said working fluid circulating in said heat engine components is the same as the working fluid circulating in said compression heat-transfer device components.

96. The heat engine according to claim 95 wherein said working fluid in said heat-engine components and in said compression heat-transfer device components is ammonia.

97. The heat engine according to claim 2 wherein at least one working fluid pump, working solution pump or heat-exchange medium circulating pump is driven by said expander work output.

98. The heat engine according to claim 3 wherein at least one working fluid pump, working solution pump or heat-exchange medium circulating pump is driven by said expander work output.

99. The heat engine according to claim 6 wherein at least one working fluid pump, working solution pump or heat-exchange medium circulating pump is driven by said expander work output.

33. A dual heat-exchange generator for an absorption heat-transfer device comprising:

a) a first fluid space containing a working solution comprising an absorbent and refrigerant;

b) a second fluid space in heat exchange relation with said first fluid space and containing a first heat exchange fluid; and

c) a third fluid space in heat exchange relation with said first fluid space and containing a second heat exchange fluid; and

d) wherein at least one of said first heat exchange fluid and said second heat exchange fluid or both said first heat exchange fluid and said second heat exchange fluid are used to heat said working solution in said first fluid space.

34. The dual heat-exchange generator according to claim 33 wherein said first fluid space is an annular space formed from an outer cylinder and an inner cylinder with a working solution inlet and a working solution outlet.

35. The dual heat-exchange generator according to claim 34 further comprising a plurality of spaced-part annular baffle plates contained in said first fluid space.

36. The dual heat-exchange generator according to claim 35 with said annular baffle plates formed as open annular sector baffle plates.

37. The dual heat-exchange generator according to claim 36 with successive alternating spaced-apart, open annular sector baffle plates facing in opposite directions.

38. The dual heat-exchange generator according to claim 36 with an interior edge of said open annular sector baffle plates attached to an exterior surface of said inner cylinder and an exterior edge of said open annular sector baffle plates attached to an interior surface of said outer cylinder.

39. The dual heat-exchange generator according to claim 38 wherein said open annular sector baffle plates are oriented in an essentially horizontal direction.

40. The dual heat-exchange generator according to claim 36 with said baffle plates having apertures formed therein for receiving tubular members forming said second fluid space.

41. The dual heat-exchange generator according to claim 40 wherein said apertures are formed as two sets of apertures with a first set of said apertures located near an outer edge of said open, annular sector baffle plates and a second set of said apertures located near an inner edge of said open, annular sector baffle plates.

42. The dual heat-exchange generator according to claim 41 wherein said working solution inlet is located in a lower portion of said first fluid space and said working solution outlet is located in an upper portion of said first fluid space.

43. The dual heat-exchange generator according to claim 42 wherein said working solution enters said working solution inlet, flows between and among said tubular members in an upwardly biased horizontal first direction within an annular space below the first open, annular sector baffle plate, then flows generally upward in the open portion of said first open, annular sector baffle plate;

then flows between and among said tubular members in an upwardly biased horizontal second direction between said first, open, annular sector baffle plate and a second open, annular sector baffle plate, in a direction substantially opposite said horizontal first direction, and then flows generally upward in the open portion of said second open, annular sector baffle plate, and then between and among said tubular members in an upwardly biased horizontal direction parallel to said horizontal first direction between said second open, annular sector baffle plate and a third open, annular sector baffle plate, repeating said reversal of said direction between adjacent sets of open, annular sector baffle plates until said working solution emerges from said first fluid space through said working solution outlet.

44. The dual heat-exchange generator according to claim 33 wherein said second fluid space is an interior tubular space formed by the interiors of tubular members.

45. The dual heat-exchange generator according to claim 44 wherein said tubular members are thin-walled, twisted fluted tube having formed therein spiraling crests and flutes on an outer tubular surface and corresponding and respective flutes and crests formed on a respective inner tubular surface.

46. The dual heat-exchange generator according to claim 45 wherein said second fluid space further comprising an upper annular fluid distribution manifold formed by:

a) an outer cylinder,

b) an inner cylinder,

c) an upper end cap,

d) an upper header plate having apertures formed therein for receiving said tubular members with said tubular members sealed to said header plate said interiors of said tubular members opening into said upper annular distribution manifold; and

e) said upper annular fluid distribution manifold having a first heat exchange fluid passage.

47. The dual heat-exchange generator according to claim 46 with said upper annular fluid distribution manifold further comprising an annular fluid distribution plate having fluid distribution apertures formed therein.

48. The dual heat-exchange generator according to claim 46 further comprising a lower annular fluid collection manifold formed by:

a) an outer cylinder,

b) an inner cylinder,

c) an lower end cap,

d) a lower header plate having apertures formed therein for receiving said tubular members with said tubular members sealed to said header plate with said interiors of said tubular members opening into said lower annular fluid collection manifold; and

e) said lower annular fluid collection manifold having a first heat exchange fluid passage.

49. The dual heat-exchange generator according to claim 48 wherein said first heat exchange fluid passage of said upper annular fluid distribution manifold is an inlet passage for first heat exchange fluid and first heat exchange fluid passage of said lower annular fluid collection manifold is an outlet passage for said first heat exchange fluid.

50. The dual heat-exchange generator according to claim 33 wherein said third fluid space is an interior cylindrical space formed by the interior of an inner cylinder.

51. The dual heat-exchange generator according to claim 50 wherein said third fluid space is an interior annular tubular space formed by a cylindrical insert placed within said inner cylinder.

52. The dual heat-exchange generator according to claim 51 with said cylindrical insert comprising:

a) a cylindrical base;

b) a plurality of cylindrical rings successively placed on top of said cylindrical base; and

c) a cylinder placed on top of said plurality of cylindrical rings.

53. The dual heat-exchange generator according to claim 50 further comprising strips of fins positioned toward the top of said third fluid space.

54. The dual heat-exchange generator according to claim 53 wherein said strips of fins extend radially from said interior of said inner cylinder into said third fluid space.

55. The dual heat-exchange generator according to claim 50 further comprising a burner located at the base of said third fluid space.

56. The dual heat-exchange generator according to claim 55 wherein said burner is a natural gas burner.

57. The dual heat-exchange generator according to claim 33 with:

a) said first fluid space being an annular space formed from;

1) an outer cylinder; and

2) an inner cylinder;

3) said first space having;

i) a lower working solution inlet;

ii) an upper working solution outlet;

iii) a plurality of horizontal, spaced-apart, open-annular-sector baffle plates with;

(a) an interior edge of said baffle plates attached perpendicularly to said exterior surface of said inner cylinder;

(b) an exterior edge of said baffle plates attached perpendicularly to an interior surface of said outer cylinder;

(c) a first set of radially formed apertures located near said interior edge of said baffle plates with each aperture receiving and aligning a twisted fluted tube;

(d) a second set of radially formed apertures located near said exterior edge of said baffle plates with each aperture receiving and aligning a twisted fluted tube; and

(e) with said apertures from said first and second sets alternating with each other about said sector annular baffle plate; and

4) wherein a working solution

i) enters said working solution inlet;

ii) flows between and among said twisted fluted tubes in an upwardly biased horizontal first direction within an annular space below the first open, annular sector baffle plate;

iii) then flows generally upward in the open portion of said first open, annular sector baffle plate;

iv) then flows between and among said twisted, fluted tubes in an upwardly biased horizontal second direction generally opposite said horizontal first direction between said first, open, annular sector baffle plate and a second open, annular sector baffle plate; and

v) then flows generally upward in the open portion of said second open, annular sector baffle plate, and

vi) then between and among said twisted fluted tubes in an upwardly biased horizontal direction parallel to said horizontal first direction between said second open, annular sector baffle plate and a third open, annular sector baffle plate; and

vii) repeating said reversal of said direction between adjacent sets of open, annular sector baffle plates and between and among said twisted, fluted tubes until said working solution emerges from said first fluid space through said working solution outlet;

b) a second fluid space is an interior tubular space formed by;

1) the interiors of a plurality of said thin-walled, twisted, fluted tubes with spiraling crests on an exterior surface of said tubes and associated flutes on an interior surface of said tubes and with spiraling flutes on said exterior surface of said tubes and associated crests on said interior surface of said tube;

2) an upper annular fluid distribution manifold comprising;

i) said outer cylinder;

ii) said inner cylinder;

iii) an upper end cap,

iv) an upper header plate having apertures formed therein for receiving said twisted fluted tubes with said twisted fluted tubes sealed to said header plate and with said interior tubular space of said twisted fluted tubes opening into said upper annular distribution manifold;

v) an annular fluid distribution plate having fluid distribution apertures formed therein; and

vi) a heat exchange fluid inlet;

3) a lower annular fluid collection manifold comprising;

i) said outer cylinder,

ii) said inner cylinder,

iii) a lower end cap,

iv) a lower header plate having apertures formed therein for receiving said twisted, fluted tubes with said twisted fluted tubes sealed to said header plate with said interior tubular space of said twisted fluted tubes opening into said lower annular fluid collection manifold; and

v) a first heat exchange outlet;

c) a third annular fluid space formed by;

1) said inner cylinder; and

2) a cylindrical insert placed within said inner cylinder with said cylindrical insert comprising;

i) a cylindrical base;

ii) a plurality of cylindrical rings successively placed on top of said cylindrical base; and

iii) a cylinder placed on top of said plurality of cylindrical rings; and

3) said third annular fluid space having in its lower portion a fossil fuel burner.

58. The dual heat-exchange generator according to claim 33 wherein:

a) said first fluid space is an annular space formed from an exterior of a first cylinder and an interior of a second cylinder, and a portion of base;

with said annular space having an inlet and an outlet;

b) said second fluid space in heat exchange relation with said first fluid space is an annular space formed from an exterior of said second cylinder, an interior of a third cylinder, an annular top and a portion of base and having an inlet and an outlet; and

c) said third fluid space, in heat exchange relation with said first fluid space, is an annular space formed from an interior of said first cylinder, an exterior of a fourth cylinder and a portion of base with a fossil fuel burner located in said base portion of said third fluid space.

59. The dual heat-exchange generator according to claim 58 further comprising a separator with an inlet connection from said first fluid space, a vapor outlet, and a solution outlet.

60. The dual heat-exchange generator according to claim 33 wherein:

a) said first fluid space is an annular space having a horizontal section and a vertical section with said horizontal section formed from an exterior of a horizontal portion of a first cylinder, an interior of a horizontal portion of a second cylinder, and a portion of base and open to a vertical section formed from an exterior of a vertical section of said first cylinder, and an interior of a vertical portion of said second cylinder, with said horizontal section having an inlet formed therein and said vertical section having an outlet;

b) said second fluid space is an annular space comprising a horizontal section and a vertical section with said horizontal and said vertical section formed as the interior tube spiral-wrapped about said exterior of said horizontal cylinder and said vertical cylinder and having an inlet and an outlet for said first heat exchange fluid; and

c) said third fluid space is a cylindrical space comprising a horizontal section and a vertical section and containing a burner in said horizontal section.

61. The dual heat-exchange generator according to claim 60 further comprising a separator with an inlet connection from said first fluid space vertical section, a vapor outlet, and a solution outlet.

62. The dual heat-exchange generator according to claim 60 further comprising an exhaust distributor attached to the interior wall of vertical section of said vertical cylinder.

63. The dual heat-exchange generator according to claim 33 wherein:

a) said first fluid space is a cylindrical space formed from an interior of a first cylinder;

b) said second fluid space in heat exchange relation with said first fluid space is an interior tubular space formed by a plurality of tubular vertical members opening to an upper manifold with an inlet and a lower manifold with an outlet; and

c) said third fluid space, in heat exchange relation with said first fluid space, is an interior tubular space formed from by a plurality of tubular vertical members and having a fossil fuel burner located in a base portion of said third fluid space.

64. The dual heat-exchange generator according to claim 63 further comprising a separator with an inlet connection from said first fluid space, a vapor outlet, and a solution outlet.

65. The dual heat-exchange generator according to claim 63 further comprising a set of alternating sector baffle plates having apertures formed therein for said tubular vertical members forming said second fluid space and said tubular vertical members forming said third fluid space.