Storage of Excess Heat in Cold Side of Heat Engine

• US 20180179916A1
• Filed: 12/28/2016
• Published: 06/28/2018
• Est. Priority Date: 12/28/2016
• Status: Active Grant

• Current Assignee: Malta, Inc.
• Original Assignee: X Development LLC (Alphabet Inc.)
• Inventors: Larochelle, Philippe, Apte, Raj
• Granted Patent: US 10,233,787 B2
• Time in Patent Office: Days
• CPC Class Codes: F01K 13/02 Controlling, e.g. stopping or starting
• CPC Class Codes: F01K 25/06 using mixtures of different fluids plants using mixtures of steam and gas F01K21/04
• CPC Class Codes: F01K 25/103 Carbon dioxide F01K25/065 takes precedence
• CPC Class Codes: F01K 3/02 Use of accumulators and specific engine types; Control thereof
• CPC Class Codes: F01K 3/06 the engine being of extraction or non-condensing type F01K3/004 takes precedence
• CPC Class Codes: F01K 3/12 having two or more accumulators
• CPC Class Codes: F01K 3/18 having heaters having both steam accumulator and heater F01K3/14; steam heaters per se F22
• CPC Class Codes: F01K 7/16 the engines being only of turbine type the engines using steam of critical or overcritical pressure F01K7/32; the engines being of extraction or non-condensing type F01K7/34
• CPC Class Codes: F01K 7/38 the engines being of turbine type
• CPC Class Codes: F02C 1/10 Closed cycles
• CPC Class Codes: F02C 7/143 before or between the compressor stages
• CPC Class Codes: F22B 1/006 using solar heat solar heat collectors per se F24S; devices for producing mechanical power from solar energy F03G6/00
• CPC Class Codes: F25B 13/00 Compression machines, plants or systems, with reversible cycle defrosting cycles F25B47/02
• CPC Class Codes: F25B 2400/14 Power generation using energy from the expansion of the refrigerant
• CPC Class Codes: F25B 25/005 using primary and secondary systems
• CPC Class Codes: F25B 9/00 Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
• CPC Class Codes: F25B 9/06 using expanders F25B9/10 takes precedence
• CPC Class Codes: Y02E 60/14 Thermal energy storage

Abstract

Extra heat in a closed cycle power generation system, such as a reversible closed Brayton cycle system, may be dissipated between discharge and charge cycles. An extra cooling heat exchanger may be added on the discharge cycle and disposed between a cold side heat exchanger and a compressor inlet. Additionally or alternatively, a cold thermal storage medium passing through the cold side heat exchanger may be allowed to heat up to a higher temperature during the discharge cycle than is needed on input to the charge cycle and the excess heat then dissipated to the atmosphere.

Claims

1. A system comprising:

a compressor;

a recuperator;

a hot side heat exchanger;

a turbine;

a cold side heat exchanger;

a cooling heat exchanger; and

a working fluid circulating in a closed cycle path through, in sequence, the compressor, the recuperator, the hot side heat exchanger, the turbine, the recuperator, the cooling heat exchanger, and the cold side heat exchanger, wherein the cooling heat exchanger is configured to remove heat from the working fluid.

2. The system of claim 1 further comprising:

a first cold side thermal storage (“

CTS”

) tank;

a second CTS tank; and

a CTS medium flowing from the first CTS tank, through the cold side heat exchanger, and to the second CTS tank.

3. The system of claim 2, wherein the CTS medium is hexane.

4. The system of claim 2 further comprising:

a first hot side thermal storage (“

HTS”

) tank;

a second HTS tank; and

an HTS medium flowing from the first HTS tank, through the hot side heat exchanger, and to the second HTS tank.

5. The system of claim 4, wherein the HTS medium is molten salt.

6. The system of claim 1, wherein the cooling heat exchanger is a radiator, wherein the working fluid circulating through the cooling heat exchanger expels heat to air.

7. The system of claim 1, wherein the cooling heat exchanger circulates a thermal fluid in thermal contact with a heat sink.

8. The system of claim 7, wherein the heat sink is a cooling tower.

9. A system comprising:

a compressor;

a recuperator;

a hot side heat exchanger;

a turbine;

a cold side heat exchanger;

a working fluid circulating in a closed cycle path through, in sequence, the compressor, the recuperator, the hot side heat exchanger, the turbine, the recuperator, and the cold side heat exchanger;

a cold side thermal storage (“

CTS”

) medium;

a first CTS tank;

an intermediate CTS tank;

a CTS heat exchanger, wherein the CTS heat exchanger is configured to remove heat from the CTS medium;

a second CTS tank;

a first flow path configured to flow CTS medium from the first CTS tank, through the cold side heat exchanger, and to the intermediate CTS tank; and

a second flow path configured to flow CTS medium from the intermediate CTS tank, through the CTS heat exchanger, and to the second CTS tank.

10. The system of claim 9, wherein the CTS medium is hexane.

11. The system of claim 9 further comprising:

a first hot side thermal storage (“

HTS”

) tank;

a second HTS tank; and

an HTS medium flowing from the first HTS tank, through the hot side heat exchanger, and to the second HTS tank.

12. The system of claim 11, wherein the CTS heat exchanger is a cooling tower.

13. The system of claim 11, wherein the CTS heat exchanger is a radiator, wherein the CTS medium flowing through the CTS heat exchanger expels heat to air.

14. The system of claim 11, further comprising a third flow path configured to flow CTS medium from the second CTS tank to the first flow path and inject CTS medium from the second CTS tank into the first flow path.

15. The system of claim 14, wherein the third flow path intersects the first flow path at a location intermediate to the first flow path entering the cold side heat exchanger and the first flow path exiting the heat exchanger.

16. A method comprising:

in a closed cycle system operating in a power generation mode, circulating a working fluid through a closed cycle fluid path including, in sequence, a compressor, a recuperator, a hot side heat exchanger, a turbine, the recuperator, and a cold side heat exchanger;

flowing a cold side thermal storage (“

CTS”

) medium at a first variable flow rate from a first CTS tank, through the cold side heat exchanger and in thermal contact with the working fluid, and to an intermediate CTS tank; and

flowing the CTS medium from the intermediate CTS tank, through a CTS heat exchanger, and to a second CTS tank, wherein the CTS heat exchanger is configured to remove heat from the CTS medium.

17. The method of claim 16, wherein the closed cycle system is a closed Brayton cycle system.

18. The method of claim 16, further comprising varying the first variable flow rate based on a temperature of the CTS medium.

19. The method of claim 18, further comprising flowing the CTS medium at a second variable flow rate from the second tank to the cold side heat exchanger.

20. The method of claim 19, further comprising varying the second variable flow rate based on a temperature of the CTS medium.