System and method for warm air space heating with electrical power generation

• US 7,040,544 B2
• Filed: 11/07/2003
• Issued: 05/09/2006
• Est. Priority Date: 11/07/2003
• Status: Active Grant

• Current Assignee: Climate Energy LLC
• Original Assignee: Climate Energy LLC
• Inventors: Guyer, Eric C.
• Primary Examiner(s): Boles, Derek S.
• Application Number:
  US10/704,358
• Publication Number:
  US 20050098643A1
• Time in Patent Office: 914 Days
• Field of Search: 237/12.1, 237/12.3 B, 237/2.A, 60/391.82, 606/14, 606/60
• US Class Current: 237/12.1
• CPC Class Codes: F24D 18/00 Small-scale combined heat and power [CHP] generation systems specially adapted for domestic heating, space heating or domestic hot-water supply
• CPC Class Codes: F24D 2101/30 Fuel cells
• CPC Class Codes: F24D 2101/70 Electric generators driven by internal combustion engines [ICE]
• CPC Class Codes: F24D 2101/80 Electric generators driven by external combustion engines, e.g. Stirling engines
• CPC Class Codes: F24D 2103/13 characterised by their heat exchangers
• CPC Class Codes: F24D 2103/17 Storage tanks
• CPC Class Codes: F24D 2105/00 Constructional aspects of small-scale CHP systems
• CPC Class Codes: F24D 2105/10 Sound insulation
• CPC Class Codes: F24D 3/08 in combination with systems for domestic hot-water supply
• CPC Class Codes: F24D 5/02 operating with discharge of hot air into the space or area to be heated
• CPC Class Codes: Y02E 20/14 Combined heat and power generation [CHP]

Abstract

This invention provides a system and method for cogeneration of building heat and electric power and that efficiently interfaces a warm air heating system with a liquid-cooled electric power generator. The system and method utilizes an electric generator that is rated at near the time-averaged electric power consumption for the building. This generator is operated as the priority source of heat for the building, but normally only when there is a demand for heat in building. In this manner, the generator can run to generate a significant part of the building'"'"'s electric power but in a manner that is typically supplemented in variable quantities by power from a public power grid. The heat output is directed via a liquid coolant circuit on the generator, as needed, to the warm air heating unit for the building. The warm air heating unit blows return air through a cabinet and out to the supply duct(s). The warm liquid coolant is directed through a primary heat exchanger in the cabinet. The air is passed over this primary heat exchanger to provide heat to the building. When heat from primary heat exchanger is insufficient to heat the building fully, an auxiliary heater, operated typically by burning fuel, supplements the heat through one or more auxiliary heat exchangers arranged in line along the airflow path with the primary heat exchanger. The blower that directs the airflow is controlled variably in speed to create the most efficient use of electric power by the blower and a desirable heated air delivery temperature.

Claims

1. A system for the space-heating of a building to a desired temperature and generation of electrical power comprising:

a fuel-burning electric power generator being electrically connected to the building electrical service in conjunction with an electrical connection from an external electrical power source, the electric power generator being constructed and arranged to transfer heat produced by the generator therefrom to a first circulating liquid stream;

an air blower through which airflow is driven for heating the building;

a primary heat exchanger mounted inline with the air blower so as to transfer heat to the airflow, the primary heat exchanger receiving heat from the first circulating liquid stream;

an auxiliary heater, fueled by combustible fuel, located in line with the blower so as to transfer additional heat to the airflow, the auxiliary heater being heated by an auxiliary heat source separate from and not thermally connected to the electric generator; and

a control module that operates the primary heat exchanger, the auxiliary heater, is the blower and the electric power generator to maintain the desired temperature while optimizing utilization of electric power generator.

3. The system as set forth in claim 1 wherein the blower is constructed and arranged to operate at a plurality of different speed levels to produce different levels of airflow, each of the speed levels being controlled by the control module.

4. The system as set forth in claim 1 wherein the auxiliary heater includes a heat exchanger that receives heat from a second circulated liquid stream that is heated by an auxiliary liquid heater.

5. The system as set forth in claim 1 wherein the auxiliary heater comprises a second circulated liquid stream that is heated by an auxiliary liquid heater and the second circulated liquid stream is directed to the primary heat exchanger in combination with the first circulated liquid stream.

6. The system as set forth in claim 1 wherein the control module is constructed and arranged to control a rate of heat transfer from the auxiliary heater to the airflow by controlling a rate at which fuel is burned by the auxiliary heater.

7. The system as set forth in claim 6 wherein the control module is constructed and arranged to vary the blower speed in response to a total amount of heat transferred to the airflow from both the primary heat exchanger and the auxiliary heater, whereby a higher airflow rate is provided at a higher amount of heat transfer from both the primary heat exchanger and the auxiliary heat exchanger.

8. The system as set forth in claim 1 wherein the control module is constructed and arranged to:

a) first exclusively operate the primary heat exchanger to transfer heat to the airflow, and

b) if space heat demand cannot be satisfied by (a), then operate the auxiliary heater in combination with the primary heat exchanger to transfer the additional heat to the airflow.

12. The system as set forth in claim 1 wherein the control module is constructed and arranged to direct electrical power to a plurality of components of the system so as to maintain operation of the primary heat exchanger, air blower and auxiliary heater to provide space heat to the building at a desired temperature.

15. The system as set forth in claim 1 wherein the first circulated liquid stream is directed to a heat exchanger that transfers heat to domestic water for the building.

17. The system as set forth in claim 1 wherein the control module and the blower are constructed and arranged to operate the blower at a plurality of airflow speeds and herein the control module is adapted to operate the blower at a predetermined low speed when heat is transferred to the airflow only from the primary heat exchanger and at a higher speed than the predetermined low speed when heat is transferred to the airflow from both the primary heat exchanger and the auxiliary heater.

18. The system as set forth in claim 1 wherein the control module is operatively connected to each of an indoor thermostat and a remote control panel that displays system operating status and that enables control of system component operation by a user.

19. The system as set forth in claim 18 further comprising an outdoor temperature sensor operatively connected with the control module so as to enable the module to adjust system performance based upon the outdoor temperature.

20. The system as set forth in claim 1 further comprising a cabinet that encloses together the air blower, the primary heat exchanger and the auxiliary heater.

21. The system as set forth in claim 20 further comprising an air-cooling unit located in line with the air blower.

22. The system as set forth in claim 1 wherein the control module includes an interconnection that can be accessed remotely to operate the electric power generator including enabling operation of the electric power generator when the external power source is unavailable.

23. The system as set forth in claim 1 wherein the electric power generator includes an engine that is one of a (a) liquid-cooled internal combustion engine, (b) liquid-cooled Stirling engine, (c) steam engine, and (d) liquid-cooled fuel cell.

24. The system as set forth in claim 1 wherein at least one of the first circulated liquid stream and the auxiliary heater transfer heat to at least one heat-using device in the building.

41. The system of claim 1 wherein the first liquid circulating stream includes an automatic temperature-operated valve that bypasses all or part of the first circulating liquid stream around the primary heat exchanger during a condition of operation that produces a temperature below a desired minimum value in the first liquid circulating stream as the first circulating liquid stream enters the electric power generator.

2. A system for the space-heating of a building to a desired temperature and generation of electrical power comprising:

a fuel-burning electric power generator being electrically connected to the building electrical service in conjunction with an electrical connection from an external electrical power source, the electric power generator being constructed and arranged to transfer heat produced by the generator therefrom to a first circulating liquid stream;

an air blower through which airflow is driven for heating the building;

a primary heat exchanger mounted inline with the air blower so as to transfer heat to the airflow, the primary heat exchanger receiving heat from the first circulating liquid stream;

an auxiliary heater located in line with the blower so as to transfer additional heat to the airflow, the auxiliary heater being heated by an auxiliary heat source separate from and not thermally connected to the electric generator;

a control module that operates the primary heat exchanger, the auxiliary heater, the blower and the electric power generator to maintain the desired temperature while optimizing utilization of electric power generator; and

wherein the auxiliary heater includes a non-condensing combustion gas type heat exchanger located downstream in the airflow of the primary heat exchanger and a condensing combustion gas type heat exchanger located upstream of the primary heat exchanger and being interconnected by a bridge around the primary heat exchanger to the condensing combustion gas type heat exchanger.

35. The system as set forth in claim 2 wherein the blower is constructed and arranged to operate at a plurality of different speed levels to produce different levels of airflow, each of the speed levels being controlled by the control module.

9. A system for the space-heating of a building to a desired temperature and generation of electrical power comprising:

a fuel-burning electric power generator being electrically connected to the building electrical service in conjunction with an electrical connection from an external electrical power source, the electric power generator being constructed and arranged to transfer heat produced by the generator therefrom to a first circulating liquid stream;

an air blower through which airflow is driven for heating the building;

a primary heat exchanger mounted inline with the air blower so as to transfer heat to the airflow, the primary heat exchanger receiving heat from the first circulating liquid stream;

an auxiliary heater located in line with the blower so as to transfer additional heat to the airflow, the auxiliary heater being heated by an auxiliary heat source separate from and not thermally connected to the electric generator;

a control module that operates the primary heat exchanger, the auxiliary heater, the blower and the electric power generator to maintain the desired temperature while optimizing utilization of electric power generator; and

wherein the electric power generator includes a vent pipe for generator combustion gasses interconnected with a vent pipe from the auxiliary heater for auxiliary heater combustion gasses.

10. The system as set forth in claim 9 wherein the electric power generator is located in an interior space of the building.

11. The system as set forth in claim 9 wherein the electric power generator is located outside the building with an insulated cover enclosing conduits for carrying the first circulating liquid stream and a line for draining condensate from the electric power generator.

13. A system for the space-heating of a building to a desired temperature and generation of electrical power comprising:

a fuel-burning electric power generator being electrically connected to the building electrical service in conjunction with an electrical connection from an external electrical power source, the electric power generator being constructed and arranged to transfer heat produced by the generator therefrom to a first circulating liquid stream;

an air blower through which airflow is driven for heating the building;

a primary heat exchanger mounted inline with the air blower so as to transfer heat to the airflow, the primary heat exchanger receiving heat from the first circulating liquid stream;

an auxiliary heater located in line with the blower so as to transfer additional heat to the airflow, the auxiliary heater being heated by an auxiliary heat source separate from and not thermally connected to the electric generator;

a control module that operates the primary heat exchanger, the auxiliary heater, the blower and the electric power generator to maintain the desired temperature while optimizing utilization of electric power generator;

wherein the control module is constructed and arranged to direct electrical power to a plurality of components of the system so as to maintain operation of the primary heat exchanger, air blower and auxiliary heater to provide space heat to the building at a desired temperature; and

wherein the control module and the electric power generator are each constructed and arranged to operate the electric power generator at an electric power output level greater than a continuous running electric power output level when power is unavailable from the external electric power source, the electric power generator being operable while power is unavailable from the external electric power source with or without a request for space heat.

14. The system as set forth in claim 13 further comprising

a heat dissipater interconnected with the first circulated liquid stream, to dissipate heat to an outdoor location when a request for space heat is not present.

16. A system for the space-heating of a building to a desired temperature and generation of electrical power comprising:

a fuel-burning electric power generator being electrically connected to the building electrical service in conjunction with an electrical connection from an external electrical power source, the electric power generator being constructed and arranged to transfer heat produced by the generator therefrom to a first circulating liquid stream;

an air blower through which airflow is driven for heating the building;

a primary heat exchanger mounted inline with the air blower so as to transfer heat to the airflow, the primary heat exchanger receiving heat from the first circulating liquid stream;

an auxiliary heater located in line with the blower so as to transfer additional heat to the airflow, the auxiliary heater being heated by an auxiliary heat source separate from and not thermally connected to the electric generator;

a control module that operates the primary heat exchanger, the auxiliary heater, the blower and the electric power generator to maintain the desired temperature while optimizing utilization of electric power generator;

wherein the first circulated liquid stream is directed to a heat exchanger that transfers heat to domestic water for the building; and

a valve assembly for controlling the first circulated liquid stream between the primary heat exchanger and the heat exchanger that produces warmed domestic water so that priority can be given to transferring heat to the domestic water over transferring heat to the primary heat exchanger.

25. The system as set forth in clam 24 further comprising a bypass valve that directs the first circulated liquid stream away from the primary heat exchanger and to a heat exchanger that transfers heat to the at least one heat-using device.

26. A method for space heating a building and generating electric power for the electrical service of the building in conjunction with an external electric power source that is also interconnected with the building electrical service comprising the steps of:

a) operating a liquid-cooled electric power generator at a continuous running rated output level to deliver electricity to the electrical service when a request for space heat is made and while operating the electric power generator circulating coolant from the electric power generator to a primary heat exchanger inline with an air blower so as to transfer heat to an airflow driven by the blower; and

b) operating an auxiliary heater inline, with the air blower when heat transferred from the primary heat exchanger is insufficient to provide desired space heat to the building, wherein each step of operating includes providing a common combustible fuel to each of the electrical power generator and the auxiliary heater.

27. The method as set forth in claim 26 further comprising emergency-operating the electric power generator either when a demand for space heat is made or a demand for space heat is not made when electric power is unavailable from the external power source and, when a demand for space heat is not made, dissipating to an outdoor location heat in the circulated coolant.

28. The method as set forth in claim 27 wherein the step of emergency-operating includes operating the electric power generator at an output level that is higher than the continuous running rated output level.

29. The method as set forth in claim 26 further comprising providing fuel to the electric power generator and the auxiliary heater from a single fuel source.

30. The method as set forth in claim 26 further comprising operating the air blower at a low airflow speed when space heat from only the primary heat exchanger is desired and at a higher airflow speed when heat from the auxiliary heater combined with primary heat exchanger is desired.

31. The method as set forth in claim 26 further comprising controlling operation of the primary heat exchanger and the auxiliary heater to:

c) first exclusively operate the primary heat exchanger to transfer heat to the airflow, and

if space heat demand cannot be satisfied by (a), then operate the auxiliary heater in combination with the primary heat exchanger to transfer the additional heat to the airflow.

32. A system for the space-heating of a building to a desired temperature and generation of electrical power comprising:

a fuel-burning electric power generator being electrically connected to the building electrical service in conjunction with an electrical connection from an external electrical power source, the electric power generator being constructed and arranged to transfer heat produced by the generator therefrom to a first circulating liquid stream;

an air blower through Which airflow is driven for heating the building;

a primary heat exchanger mounted inline with the air blower so as to transfer heat to the airflow, the primary heat exchanger receiving heat from the first circulating liquid stream;

an auxiliary heater located in line with the blower so as to transfer additional heat to the airflow, the auxiliary heater being heated by an auxiliary heat source, being fueled by a combustible fuel, separate from and not thermally connected to the electric generator;

a control module that operates the primary heat exchanger, the auxiliary heater, the blower and the electric power generator to maintain the desired temperature while optimizing utilization of electric power generator; and

wherein the auxiliary heater is a non-condensing combustion gas type heat exchanger located downstream in the airflow of the primary heat exchanger.

36. The system as set forth in claim 32 wherein the blower is constructed and arranged to operate at a plurality of different speed levels to produce different levels of airflow, each of the speed levels being controlled by the control module.

33. A system for the space-heating of a building to a desired temperature and generation of electrical power comprising:

a fuel-burning electric power generator being electrically connected to the building electrical service in conjunction with an electrical connection from an external electrical power source, the electric power generator being constructed and arranged to transfer heat produced by the generator therefrom to a first circulating liquid stream;

an air blower through which airflow is driven for heating the building;

a primary heat exchanger mounted inline with the air blower so as to transfer heat to the airflow, the primary heat exchanger receiving heat from the first circulating liquid stream;

an auxiliary heater located in line with the blower so as to transfer additional heat to the airflow, the auxiliary heater being heated by an auxiliary heat source separate from and not thermally connected to the electric generator;

a control module that operates the primary heat exchanger, the auxiliary heater, the blower and the electric power generator to maintain the desired temperature while optimizing utilization of electric power generator; and

wherein the auxiliary heater includes both a non-condensing combustion gas type heat exchanger and a condensing combustion gas type heat exchanger located upstream of the primary heat exchanger, wherein the non-condensing combustion gas type heat exchanger and the condensing combustion gas type heat exchanger are interconnected by a bridge to a common gas flow stream.

37. The system as set forth in claim 33 wherein the blower is constructed and arranged to operate at a plurality of different speed levels to produce different levels of airflow, each of the speed levels being controlled by the control module.

34. A system for the space-heating of a building to a desired temperature and generation of electrical power comprising:

a fuel-burning electric power generator being electrically connected to the building electrical service in conjunction with an electrical connection from an external electrical power source, the electric power generator being constructed and arranged to transfer heat produced by the generator therefrom to a first circulating liquid stream;

an air blower through which airflow is driven for heating the building;

a primary heat exchanger mounted inline with the air blower so as to transfer heat to the airflow, the primary heat exchanger receiving heat from the first circulating liquid stream;

an auxiliary heater located in line with the blower so as to transfer additional heat to the airflow, the auxiliary heater being heated by an auxiliary heat source, being fueled by a combustible fuel, separate from and not thermally connected to the electric generator;

a control module that operates the primary heat exchanger, the auxiliary heater, the blower and the electric power generator to maintain the desired temperature while optimizing utilization of electric power generator; and

wherein the auxiliary heater is a non-condensing combustion gas type heat exchanger located upstream in the airflow of the primary heat exchanger.

38. The system as set forth in claim 34 wherein the blower is constructed and arranged to operate at a plurality of different speed levels to produce different levels of airflow, each of the speed levels being controlled by the control module.

39. A system for the space-heating of a building to a desired temperature and generation of electrical power comprising:

a fuel-burning electric power generator being electrically connected to the building electrical service in conjunction with an electrical connection from an external electrical power source, the electric power generator being constructed and arranged to transfer heat produced by the generator therefrom to a first circulating liquid stream;

an air blower through which airflow is driven for heating the building;

a primary heat exchanger mounted inline with the air blower so as to transfer heat to the airflow, the primary heat exchanger receiving heat from the first circulating liquid stream;

an auxiliary heater, fueled by combustible fuel, located in line with the blower so as to transfer additional heat to the airflow, the auxiliary heater being heated by an auxiliary heat source separate from and not thermally connected to the electric generator, wherein the auxiliary heater includes a heat exchanger that receives heat from a second circulated liquid stream that is heated by an auxiliary liquid heater; and

a control module that operates the primary heat exchanger, the auxiliary heater, the blower and the electric power generator to maintain the desired temperature while optimizing utilization of electric power generator.

40. The system as set forth in claim 39 wherein the second circulated liquid stream is directed to the primary heat exchanger in combination with the first circulated liquid stream.

42. A system for the space-heating of a building to a desired temperature and generation of electrical power comprising:

a fuel-burning electric power generator being electrically connected to the building electrical service in conjunction with an electrical connection from an external electrical power source, the electric power generator being constructed and arranged to transfer heat produced by the generator therefrom to a first circulating liquid stream;

an air blower through which airflow is driven for heating the building;

a primary heat exchanger mounted inline with the air blower so as to transfer heat to the airflow, the primary heat exchanger receiving heat from the first circulating liquid stream;

an auxiliary heater located in line with the blower so as to transfer additional heat to the airflow, the auxiliary heater being heated by an auxiliary heat source, being fueled by a combustible fuel, separate from and not thermally connected to the electric generator;

a control module that operates the primary heat exchanger, the auxiliary heater, the blower and the electric power generator to maintain the desired temperature while optimizing utilization of electric power generator; and

wherein the auxiliary heater includes both a non-condensing combustion gas type heat exchanger and a condensing combustion gas type heat exchanger located downstream of the primary heat exchanger, wherein the non-condensing combustion gas type heat exchanger and the condensing combustion gas type heat exchanger are interconnected by a bridge to a common gas flow stream.

43. The system as set forth in claim 42 wherein the blower is constructed and arranged to operate at a plurality of different speed levels to produce different levels of airflow, each of the speed levels being controlled by the control module.