Pumped Thermal Storage Cycles with Recuperation

• US 20190195571A1
• Filed: 02/28/2019
• Published: 06/27/2019
• Est. Priority Date: 09/27/2012
• Status: Active Grant

• Current Assignee: Malta, Inc.
• Original Assignee: Malta, Inc.
• Inventors: Laughlin, Robert B., Larochelle, Philippe, Cizek, Nicholas
• Granted Patent: US 11,156,385 B2
• Time in Patent Office: Days
• CPC Class Codes: F01K 13/02 Controlling, e.g. stopping or starting
• CPC Class Codes: F01K 3/00 Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein regenerating exhaust steam F01K19/00
• CPC Class Codes: F01K 3/12 having two or more accumulators
• CPC Class Codes: F01K 3/185 using waste heat from outside the plant F02G5/00 takes precedence
• CPC Class Codes: F01K 3/20 with heating by combustion gases of main boiler
• CPC Class Codes: F02C 1/10 Closed cycles
• CPC Class Codes: F02C 6/14 Gas-turbine plants having means for storing energy, e.g. for meeting peak loads
• CPC Class Codes: F05D 2250/90 Variable geometry
• CPC Class Codes: F24S 60/10 using latent heat
• CPC Class Codes: F28D 15/00 Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies F28D17/00, F28D19/00, F28D20/00 take precedence
• CPC Class Codes: F28D 20/00 Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
• CPC Class Codes: F28D 2020/0047 using molten salts or liquid metals
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers
• CPC Class Codes: Y02E 20/14 Combined heat and power generation [CHP]
• CPC Class Codes: Y02E 20/16 Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]
• CPC Class Codes: Y02E 60/14 Thermal energy storage
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids

Abstract

The present disclosure provides pumped thermal energy storage systems that can be used to store electrical energy. A pumped thermal energy storage system of the present disclosure can store energy by operating as a heat pump or refrigerator, whereby net work input can be used to transfer heat from the cold side to the hot side. A working fluid of the system is capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. The system can extract energy by operating as a heat engine transferring heat from the hot side to the cold side, which can result in net work output. Systems of the present disclosure can employ solar heating for improved storage efficiency.

Claims

1. A system comprising:

a compressor;

a hot side heat exchanger;

a turbine;

a cold side heat exchanger;

a working fluid;

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

a pressure tank in fluid communication with the working fluid on the high pressure leg over a fluid connection between the high pressure leg and the pressure tank, wherein the pressure tank is configured for use in removing a quantity of the working fluid from the closed cycle fluid path by opening the fluid connection, such that pressure of the working fluid in the high pressure leg decreases and pressure of the working fluid in the pressure tank increases.

2. The system of claim 1, wherein the fluid connection connects to the high pressure leg at a location subsequent to an outlet of the hot side heat exchanger and before an inlet of the turbine.

3. The system of claim 2, wherein the location is adjacent to the inlet of the turbine.

4. The system of claim 1, wherein the pressure tank is configured to contain working fluid at a pressure intermediate to respective pressures of the high pressure leg and the low pressure leg.

5. The system of claim 1, wherein the fluid connection contains a valve for controlling an amount of working fluid in the pressure tank.

6. The system of claim 1, wherein the system is configured to operate in a heat pump mode and a heat engine mode.

7. The system of claim 1, further comprising:

a cold thermal storage (“

CTS”

) medium;

a hot thermal storage (“

HTS”

) medium,

wherein the working fluid exchanges heat with the HTS medium in the hot side heat exchanger, and

wherein the working fluid exchanges heat with the CTS medium in the cold side heat exchanger.

8. A system comprising:

a compressor;

a hot side heat exchanger;

a turbine;

a cold side heat exchanger;

a working fluid;

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

a pressure tank in fluid communication with the working fluid on the low pressure leg over a fluid connection between the low pressure leg and the pressure tank, wherein the pressure tank is configured for use in adding a quantity of the working fluid to the closed cycle fluid path by opening the fluid connection, such that pressure of the working fluid in the low pressure leg increases and pressure of the working fluid in the pressure tank decreases.

9. The system of claim 8, wherein the fluid connection connects to the low pressure leg at a location subsequent to an outlet of the cold side heat exchanger and before an inlet of the compressor.

10. The system of claim 8, wherein the location is adjacent to the inlet of the compressor.

11. The system of claim 8, wherein the pressure tank is configured to contain working fluid at a pressure intermediate to respective pressures of the high pressure leg and the low pressure leg.

12. The system of claim 8, wherein the fluid connection contains a valve for controlling an amount of working fluid in the pressure tank.

13. The system of claim 8, wherein the system is configured to operate in a heat pump mode and a heat engine mode.

14. The system of claim 8, further comprising:

a cold thermal storage (“

CTS”

) medium;

a hot thermal storage (“

HTS”

) medium,

wherein the working fluid exchanges heat with the HTS medium in the hot side heat exchanger, and

wherein the working fluid exchanges heat with the CTS medium in the cold side heat exchanger.

15. A method comprising:

in a closed cycle fluid path of a pumped thermal system, circulating a working fluid through the closed cycle fluid path including, in sequence, a compressor, a hot side heat exchanger, a turbine, and a cold side heat exchanger, wherein the closed cycle fluid path comprises a high pressure leg and a low pressure leg; and

removing a quantity of the working fluid from the closed cycle fluid path by opening a fluid connection between the high pressure leg and a pressure tank, such that pressure of the working fluid in the high pressure leg decreases and pressure of the working fluid in the pressure tank increases.

16. The method of claim 15, wherein the fluid connection connects to the high pressure leg at a location subsequent to an outlet of the hot side heat exchanger and before an inlet of the turbine.

17. The method of claim 16, wherein the location is adjacent to the inlet of the turbine.

18. The method of claim 15, wherein the pressure tank is configured to contain working fluid at a pressure intermediate to respective pressures of the high pressure leg and the low pressure leg.

19. The method of claim 15, wherein the fluid connection contains a valve for controlling an amount of working fluid in the pressure tank.

20. The method of claim 15, wherein the pumped thermal system is configured to operate in a heat pump mode and a heat engine mode.

21. A method comprising:

in a closed cycle fluid path of a pumped thermal system, circulating a working fluid through the closed cycle fluid path including, in sequence, a compressor, a hot side heat exchanger, a turbine, and a cold side heat exchanger, wherein the closed cycle fluid path comprises a high pressure leg and a low pressure leg; and

adding a quantity of the working fluid to the closed cycle fluid path by opening a fluid connection between the low pressure leg and a pressure tank, such that pressure of the working fluid in the low pressure leg increases and pressure of the working fluid in the pressure tank decreases.

22. The method of claim 21, wherein the fluid connection connects to the low pressure leg at a location subsequent to an outlet of the cold side heat exchanger and before an inlet of the compressor.

23. The method of claim 22, wherein the location is adjacent to the inlet of the compressor.

24. The method of claim 21, wherein the pressure tank is configured to contain working fluid at a pressure intermediate to respective pressures of the high pressure leg and the low pressure leg.

25. The method of claim 21, wherein the fluid connection contains a valve for controlling an amount of working fluid in the pressure tank.

26. The method of claim 21, wherein the pumped thermal system is configured to operate in a heat pump mode and a heat engine mode.