Variable Pressure Turbine

• US 20180187595A1
• Filed: 12/30/2016
• Published: 07/05/2018
• Est. Priority Date: 12/30/2016
• Status: Active Grant

• Current Assignee: Malta, Inc.
• Original Assignee: X Development LLC (Alphabet Inc.)
• Granted Patent: US 10,801,404 B2
• Time in Patent Office: Days
• 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 1/105 construction; details
• CPC Class Codes: F02C 6/14 Gas-turbine plants having means for storing energy, e.g. for meeting peak loads
• CPC Class Codes: F02C 9/24 Control of the pressure level in closed cycles
• CPC Class Codes: F05D 2240/35 Combustors or associated equipment
• CPC Class Codes: H02K 7/1823 structurally associated with turbines or similar engines
• CPC Class Codes: Y02E 20/14 Combined heat and power generation [CHP]

Abstract

Systems and methods relating to variable pressure turbines are disclosed. A power generation system may include a closed cycle system configured to generate power, a combustor, and a control system. The closed cycle system may include a working fluid circulating in a closed cycle path. The combustor may provide thermal energy to the working fluid. Further, the control system may be configured to determine to increase an amount of power generated by the closed cycle system, and in response to the determination to increase the amount of power generated by the closed cycle system, cause an increase in pressure of the working fluid in the closed cycle path.

Claims

1. A power generation system comprising:

a closed cycle system configured to generate power, the closed cycle system comprising a working fluid circulating in a closed cycle path through, in sequence, a compressor, a hot side heat exchanger, a turbine, and a cold side heat exchanger, wherein the closed cycle path comprises a high pressure leg and a low pressure leg;

a combustor, wherein the combustor provides thermal energy to the working fluid via the hot side heat exchanger; and

a control system configured to;

determine to increase an amount of power generated by the closed cycle system,

and in response to the determination to increase the amount of power generated by the closed cycle system, cause an increase in pressure of the working fluid in the closed cycle path.

2. The power generation system of claim 1, wherein the closed cycle system comprises a closed Brayton cycle system.

3. The power generation system of claim 1, wherein the control system is further configured to:

determine to decrease an amount of power generated by the closed cycle system, and

in response to the determination to decrease the amount of power generated by the closed cycle system, cause a decrease in pressure of the working fluid in the closed cycle path.

4. The power generation system of claim 3 further comprising:

a piston reservoir comprising a reservoir with a variable volume for holding working fluid and a piston configured to change the volume of the reservoir, wherein the piston reservoir is in fluid communication with the closed cycle path and the reservoir constitutes a portion of a volume of the closed cycle path,

wherein the control system is configured to cause an increase in pressure of the working fluid in the closed cycle path by directing the piston to reduce the volume of the reservoir, thereby reducing the volume of the closed cycle path, and

wherein the control system is configured to cause a decrease in pressure of the working fluid in the closed cycle path by directing the piston to increase the volume of the reservoir, thereby increasing the volume of the closed cycle path.

5. The power generation system of claim 3 further comprising:

a pump in fluid communication with the closed cycle path,

wherein the control system is configured to cause an increase in pressure of the working fluid in the closed cycle path by directing the pump to pump working fluid into the closed cycle path, and

wherein the control system is configured to cause a decrease in pressure of the working fluid in the closed cycle path by directing the pump to pump working fluid out of the closed cycle path.

6. The power generation system of claim 3 further comprising:

a storage tank containing working fluid at an intermediate pressure between a pressure of the working fluid in the high pressure leg and a pressure of the working fluid in the low pressure leg, wherein the storage tank is coupled to the high pressure leg and the low pressure leg by a first valve and a second valve, respectively,

wherein the control system is configured to cause an increase in pressure of the working fluid in the closed cycle path by directing the first valve to be closed and the second valve to be open, thereby allowing working fluid in the storage tank to enter the low pressure leg, and

wherein the control system is configured to cause a decrease in pressure of the working fluid in the closed cycle path by directing the first valve to be open and the second valve to be closed, thereby allowing working fluid in the high pressure leg to enter the storage tank.

7. The power generation system of claim 1 wherein the combustor provides thermal energy to the working fluid via an intermediate fluid that is in thermal contact with the combustor and flows through the hot side heat exchanger.

8. The power generation system of claim 1 wherein the combustor provides thermal energy to the working fluid via flue gas that flows through the hot side heat exchanger.

9. The power generation system of claim 8 wherein the flue gas is exhausted to the atmosphere after exiting the hot side heat exchanger.

10. The power generation system of claim 1 wherein the working fluid further circulates through a recuperator.

11. The power generation system of claim 1 further comprising an electrical generator coupled to the turbine and configured to provide electrical power to an external electrical system.

12. The power generation system of claim 1 further comprising a drivetrain coupled to the turbine and configured to provide mechanical power to an external drive system.

13. A method comprising:

in a closed cycle power generation system comprising a working fluid circulating in a closed cycle path through, in sequence, a compressor, a hot side heat exchanger, a turbine, and a cold side heat exchanger, wherein a combustor provides thermal energy to the working fluid via the hot side heat exchanger, determining to increase a power output level; and

in response to the determination to increase the power output level, increasing pressure of the working fluid circulating in the closed cycle path.

14. The method of claim 13, wherein the closed cycle path has a variable volume, and wherein increasing a pressure of the working fluid circulating in the closed cycle path comprises reducing the volume of the closed cycle flow path.

15. The method of claim 14, wherein reducing the volume of the closed cycle flow path comprises reducing a volume of a piston reservoir in fluid communication with the closed cycle flow path.

16. The method of claim 13, wherein increasing a pressure of the working fluid circulating in the closed cycle path comprises adding additional working fluid to the closed cycle path.

17. The method of claim 16, wherein adding additional working fluid to the closed cycle path comprises adding working fluid from a storage tank to a low pressure leg of the closed cycle path, wherein working fluid in the tank is at a pressure greater than working fluid in the low pressure leg of the closed cycle.

18. The method of claim 16, wherein adding additional working fluid to the closed cycle path comprises pumping working fluid into the closed cycle path.

19. A method comprising:

in a closed cycle power generation system comprising a working fluid circulating in a closed cycle path through, in sequence, a compressor, a hot side heat exchanger, a turbine, and a cold side heat exchanger, wherein a combustor provides thermal energy to the working fluid via the hot side heat exchanger, determining to decrease a power output level; and

in response to the determination to decrease the power output level, decreasing pressure of the working fluid circulating in the closed cycle path.

20. The method of claim 19, wherein the closed cycle path has a variable volume, and wherein decreasing a pressure of the working fluid circulating in the closed cycle path comprises increasing the volume of the closed cycle flow path.