REGENERATIVE BRAKING FOR GAS TURBINE SYSTEMS

• US 20100021284A1
• Filed: 03/17/2009
• Published: 01/28/2010
• Est. Priority Date: 03/17/2008
• Status: Active Grant

• Current Assignee: Turbocell LLC
• Original Assignee: ICR Turbine Engine Corporation
• Inventors: Donnelly, Frank, Watson, John D.
• Granted Patent: US 8,215,437 B2
• Time in Patent Office: Days
• US Class Current: 415/123
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2220/18 Reluctance machines
• CPC Class Codes: B60L 7/10 Dynamic electric regenerative braking B60L7/22 takes precedence
• CPC Class Codes: F02C 3/36 Open cycles
• CPC Class Codes: F02C 6/14 Gas-turbine plants having means for storing energy, e.g. for meeting peak loads
• CPC Class Codes: F02C 6/16 for storing compressed air
• CPC Class Codes: F02C 7/10 by means of regenerative heat-exchangers
• CPC Class Codes: F02C 9/56 with power transmission control
• CPC Class Codes: F05D 2220/76 an electrical generator
• CPC Class Codes: F05D 2240/40 Use of a multiplicity of similar components
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

The present invention is directed to an energy storage system comprised of a heat block having a relatively high specific energy capacity. The heat block can be used, for example, with a regenerative braking system for gas turbine powered vehicles to improve fuel efficiency.

Claims

1. An energy storage system, comprising:

(a) at least one heat block in thermal communication with at least one energy source, wherein the at least one heat block is configured to store thermal energy;

(b) a thermally insulative enclosure surrounding the at least one heat block; and

(c) at least one heat exchanger in thermal communication with the at least one heat block to transfer heat from the at least one heat block to a working fluid.

2. The energy storage system of claim 1, wherein the at least one energy source is at least one of a plug-in to a power grid, an electrical generator and a braking system, wherein the at least one heat block is at least one of carbon, graphite, boron nitride, boron carbide, silicon carbide, silicon dioxide, magnesium oxide, tungsten carbide and alumina, and wherein the at least one heat exchanger is in thermal communication with the at least one heat block by means of a heat transfer fluid.

3. The energy storage system of claim 1, wherein the working fluid is used in an open-cycle gas turbine.

4. The energy storage system of claim 1, wherein the working fluid is used in a closed-cycle gas turbine.

5. The energy storage system of claim 1, further comprising at least one intermediate storage block in thermal communication with the at least one heat block, wherein the at least one intermediate storage block is configured to store thermal energy, wherein the at least one heat block is at least one of carbon, graphite, boron nitride, boron carbide, silicon carbide, silicon dioxide, magnesium oxide, tungsten carbide and alumina, and wherein the at least one intermediate storage block is at least one of carbon, graphite, boron nitride, boron carbide, silicon carbide, silicon dioxide, magnesium oxide, tungsten carbide and alumina, and wherein the at least one heat exchanger is in thermal communication with the at least one intermediate storage block, whereby thermal energy flows from the at least one heat block to the at least one intermediate storage block and then from the at least one intermediate storage block to the at least one heat exchanger.

6. The energy storage system of claim 1, wherein the at least one energy source is one or more motors each associated with an axle, wherein, in a first mode, the vehicle is moving but not braking and the one or more motors are disengaged from its axle and, in a second mode, the vehicle is moving and braking and the one or more motors are engaged with its axle, and wherein the one or more motors, in the second mode, provide braking action by generating an electrical output, the electrical output being directed to a resistive grid in thermal contact with the heat block.

7. The energy storage system of claim 1, wherein the at least one energy source is one or more motors, wherein, in a first mode, the one or more motors are disengaged from a shaft of an engine and produce substantially no electrical output and, in a second mode, the one or more motors are engaged with the shaft of the engine when the shaft of the engine is disengaged from a transmission and generate an electrical output, the electrical output being directed to a resistive grid in thermal contact with the heat block.

8. The energy storage system of claim 1, wherein the at least one energy source is one or more traction motors, wherein the one or more traction motors receive, in a driven mode, electrical energy from a mechanical-to-electrical energy conversion device, and, in a braking mode, the one or more traction motors generate an electrical output, the electrical output being directed to a resistive grid in thermal contact with the heat block.

9. An energy storage system, comprising:

(a) at least one heat block, having a first energy storage capacity and a first storage temperature, in thermal communication with at least one energy source, wherein the at least one heat block is configured to store thermal energy;

(b) at least one intermediate storage block, having a second energy storage capacity and a second storage temperature, in thermal communication with the at least one heat block, wherein at least one of the following is true;

(B1) the first energy storage capacity is equal to or greater than the second energy storage capacity;

(B2) the first storage temperature is greater than the second storage temperature; and

(B3) a melting point of the heat block is equal to or greater than a melting point of the intermediate storage block; and

(c) a thermally insulative enclosure surrounding the at least one heat block and the at least one intermediate storage block.

10. The energy storage system of claim 9, wherein (B1) is true.

11. The energy storage system of claim 9, wherein (B2) is true.

12. The energy storage system of claim 9, wherein (B3) is true.

13. The energy storage system of claim 9, wherein the at least one energy source is at least one of a plug-in to a power grid, an electrical generator and a braking system, wherein the at least one heat block is at least one of carbon, graphite, boron nitride, boron carbide, silicon carbide, silicon dioxide, magnesium oxide, tungsten carbide and alumina, and wherein the at least one intermediate storage block is at least one of carbon, graphite, boron nitride, boron carbide, silicon carbide, silicon dioxide, magnesium oxide, tungsten carbide and alumina.

14. The energy storage system of claim 9, wherein a first maximum storage temperature is at least about 1,500 degrees kelvin and a second maximum storage temperature is at least about 750 degrees kelvin.

15. The energy storage system of claim 9, wherein at least most of the heat block is separated from at least most of the intermediate storage block by a space, the space including at least one of an inert and reducing fluid, the at least one of an inert and reducing fluid being substantially free of oxidants.

16. The energy storage system of claim 9, further comprising at least one heat exchanger in thermal communication with the at least one intermediate storage block to use heat from the at least one intermediate storage block for heating a working fluid, the working fluid being used by at least one gas turbine, whereby thermal energy flows from the at least one heat block to the at least one intermediate storage block and then from the at least one intermediate storage block to the at least one heat exchanger and then from the at least one heat exchanger to the working fluid of the at least one gas turbine.

17. A vehicle system, comprising:

(a) at least one gas turbine engine;

(b) at least one of a plug-in to a power grid, an electrical generator and a braking system, the a plug-in to a power grid generating electrical energy when the at least one gas turbine engine is not operating, the electrical generator generating electrical energy when the at least one gas turbine engine is idling and the braking system generating electrical energy when braking;

(c) a resistive grid to transform the electrical energy into thermal energy by resistive dissipation; and

(d) at least one heat block in thermal communication with the resistive grid to absorb the thermal energy, wherein the at least one heat block is in thermal communication with the at least one gas turbine engine.

18. The system of claim 17, wherein the electrical energy is generated by a motor connected to a shaft in mechanical communication with a transmission which is in mechanical communication with the at least one gas turbine engine, and wherein, in a first mode, the motor is disengaged from the shaft and produces substantially no electrical energy and, in a second mode, the transmission is disengaged and the motor is engaged with the shaft and generates the electrical energy in response to braking.

19. The system of claim 17 wherein the electrical energy is generated by:

(a) a first motor connected to a first shaft in mechanical communication with a transmission which is in mechanical communication with the at least one gas turbine engine; and

(b) a second motor connected to a second shaft in mechanical communication with both the at least one gas turbine engine and the transmission; and

(c) wherein, in a first mode, the first and second motors are disengaged from the shafts and produce substantially no electrical energy and, in a second mode, the second motor is engaged with the second shaft and generates the electrical energy when the vehicle is stopped and idling and, in a third mode, the first motor is engaged with the first shaft and generates the electrical energy in response to braking.

20. The system of claim 17, wherein the electrical energy is generated by one or more motors each connected to an axle in mechanical communication with the vehicle, and wherein, in a first mode, the one or more motors are disengaged from the axles and produce substantially no electrical energy and, in a second mode, the one or more motors are engaged with the axles and generate the electrical energy in response to braking.

21. The system of claim 17 wherein the at least one gas turbine is in communication with a mechanical-to-electrical conversion device which is in electrical communication with an electrical bus which is electrical communication with one or more traction motors which are in mechanical communication with one or more axles and wherein the electrical energy is generated by at least one of the mechanical-to-electrical conversion device and one or more of the traction motors, wherein, in a first mode, the one or more traction motors produce substantially no electrical energy and, in a second mode, the one or more traction motors are operated as retarder generators to generate the electrical energy in response to braking, and, in a third mode, the mechanical-to-electrical conversion device generates the electrical energy.

22. The system of claim 17, wherein a heat exchanger is in thermal communication with the heat block and transfers thermal energy from the heat block to a working fluid and wherein the heated working fluid provides substantially all the power for a gas turbine engine.

23. The system of claim 17, wherein the gas turbine engine comprises:

a first low pressure compressor to compress an input fluid to form a first input fluid at a first pressure;

an intercooler apparatus to cool the first input fluid to a lower first temperature;

a first high pressure compressor to compress the cooled first input fluid to form a second fluid at a second pressure higher than the first pressure;

a recuperator to heat the second input fluid to a higher second temperature;

a heat exchanger in thermal communication with the heat block wherein the second input fluid passes through the cold side of the heat exchanger;

a combustor to heat the second input fluid to form a third input fluid having a third temperature higher than the first and second temperatures;

a second high pressure turbine to power the first high pressure compressor in response to expansion of the third input fluid;

a second low pressure turbine to power the first low pressure compressor in response to further expansion of the third input fluid; and

a free power turbine to power an output shaft in response to further expansion of the third input fluid, wherein the working fluid is the second input fluid.

24. The system of claim 23, wherein fuel is supplied to the combustor when the second input fluid is at a temperature less than the third temperature.