THERMOELECTRIC ENERGY STORAGE SYSTEM HAVING TWO THERMAL BATHS AND METHOD FOR STORING THERMOELECTRIC ENERGY

• US 20120060501A1
• Filed: 10/14/2011
• Published: 03/15/2012
• Est. Priority Date: 04/14/2009
• Status: Active Grant

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: ABB Research Ltd. (ABB Ltd.)
• Inventors: HEMRLE, Jaroslav, Kaufmann, Lilian, Mercangoez, Mehmet
• Granted Patent: US 8,584,463 B2
• Time in Patent Office: Days
• US Class Current: 60/645
• 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: F02C 6/18 using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants using waste heat as source of energy for refrigeration plants F25B27/02; using the waste heat of a gasturbine for steam generation or in a steam cycle see F01K23/10
• CPC Class Codes: F03D 9/18 storing heat
• CPC Class Codes: F03D 9/22 the apparatus producing heat
• CPC Class Codes: F03D 9/25 the apparatus being an electrical generator F03D9/22 takes precedence
• CPC Class Codes: F03G 7/04 using pressure differences or thermal differences occurring in nature F03G7/06 takes precedence
• CPC Class Codes: F05B 2220/604 for domestic central heating or production of electricity
• CPC Class Codes: F05D 2220/64 for domestic central heating or production of electricity
• 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: Y02E 10/72 Wind turbines with rotation axis in wind direction
• CPC Class Codes: Y02E 60/14 Thermal energy storage
• CPC Class Codes: Y02E 70/30 Systems combining energy storage with energy generation of non-fossil origin

Abstract

An exemplary system and method for storing and retrieving energy in a thermoelectric energy storage system is disclosed. The thermoelectric energy storage system includes a working fluid that is circulated through a first and second heat exchanger, and a thermal storage medium that is circulated through the first heat exchanger. The second heat exchanger is in connection with a first thermal bath during a charging cycle and with a second thermal bath during a discharging cycle. In this way roundtrip efficiency is improved through minimizing the temperature difference between the first thermal bath and the hot storage tank during charging, and maximizing the temperature difference between the second thermal bath and the hot storage tank during discharging.

Claims

1. A thermoelectric energy storage system having a charging cycle for providing thermal energy to a thermal storage, and a discharging cycle for generating electricity by retrieving the thermal energy from the thermal storage, the thermoelectric energy storage system comprising;

a working fluid circuit for circulating a working fluid through a first heat exchanger and a second heat exchanger;

a thermal storage medium circuit for circulating a thermal storage medium, the thermal storage medium circuit having at least one hot storage tank coupled to a cold storage tank via the first heat exchanger;

wherein, during a charging cycle, the second heat exchanger is connected to a first thermal bath and a temperature difference between the first thermal bath and a hot storage tank is minimized, and

wherein, during a discharging cycle, the second heat exchanger is connected to a second thermal bath and a temperature difference between the second thermal bath and the hot storage tank is maximized.

2. The system according to claim 1, wherein a cooling device connected to the cold storage tank during a charging cycle.

3. The system according to claim 1, wherein a heating device is connected to the cold storage tank during a discharging cycle.

4. The system according to claim 1, wherein at least one section of a charging cycle or a discharging cycle runs transcritically.

5. The system according to claim 2, wherein in a heating device is connected to the cold storage tank during a discharging cycle.

6. The system according to claim 2, wherein at least one section of a charging cycle or a discharging cycle runs transcritically.

7. The system according to claim 3, wherein at least one section of a charging cycle or a discharging cycle runs transcritically.

8. A method for storing and retrieving energy in a thermoelectric energy storage system, comprising:

charging the system by heating a thermal storage medium, wherein the thermal storage medium circulates between at least one hot storage tank coupled to a cold storage tank;

discharging the system by heating a working fluid in a working fluid circuit with heat from the thermal storage medium and expanding the working fluid through a thermodynamic machine;

connecting a first thermal bath to the working fluid circuit during charging to minimize a temperature difference between the first thermal bath and a hot storage tank; and

connecting a second thermal bath to the working fluid circuit during discharging to maximize a temperature difference between the second thermal bath and the hot storage tank.

9. The method according to claim 8, further comprising:

connecting a cooling device to the cold storage tank during a charging cycle.

10. The method according to claim 8, further comprising:

connecting a heating device to the cold storage tank during a discharging cycle.

11. The method according to claim 8, wherein at least one section of a charging cycle or a discharging cycle is performed transcritically.

12. The method according to claim 9, further comprising:

connecting a heating device to the cold storage tank during a discharging cycle.

13. The method according to claim 9, wherein at least one section of a charging cycle or a discharging cycle is performed transcritically.

14. The method according to claim 10, wherein at least one section of a charging cycle or a discharging cycle is performed transcritically.

15. A thermoelectric energy storage system having a charging cycle and a discharging cycle, comprising:

a working fluid circuit for circulating a working fluid through a first heat exchanger and a second heat exchanger;

a thermal storage medium circuit having at least one hot storage tank coupled to a cold storage tank via the first heat exchanger,

wherein the second heat exchanger is switchably connected to a first thermal bath during the charging cycle and to a second thermal bath during the discharging cycle.

16. The system according to claim 15, wherein second heat exchanger minimizes a temperature difference between the first thermal bath and a hot storage tank.

17. The system according to claim 15, wherein second heat exchanger maximizes a temperature difference between the second thermal bath and the hot storage tank.

18. The system according to claim 15, wherein a cooling device connected to the cold storage tank during a charging cycle.

19. The system according to claim 15, wherein a heating device is connected to the cold storage tank during a discharging cycle.

20. The system according to claim 15, wherein at least one section of a charging cycle or a discharging cycle runs transcritically.