Thermoelectric energy storage system with an intermediate storage tank and method for storing thermoelectric energy

• US 8,904,793 B2
• Filed: 12/14/2011
• Issued: 12/09/2014
• Est. Priority Date: 06/18/2009
• Status: Active Grant

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: ABB Research Ltd. (ABB Ltd.)
• Inventors: Hemrle, Jaroslav, Kaufmann, Lilian, Mercangoez, Mehmet
• Primary Examiner(s): Denion, Thomas
• Assistant Examiner(s): STANEK, KELSEY L
• Application Number:
  US13/325,706
• Publication Number:
  US 20120080168A1
• Time in Patent Office: 1,091 Days
• Field of Search: 606/59, 606/43, 165/4
• US Class Current: 60/659
• CPC Class Codes: F01K 1/08 Charging or discharging of accumulators with steam peculiar to multiple accumulators F01K1/12
• CPC Class Codes: F01K 3/08 Use of accumulators and the plant being specially adapted for a specific use
• CPC Class Codes: F01K 3/12 having two or more accumulators
• CPC Class Codes: F01K 3/14 having both steam accumulator and heater, e.g. superheating accumulator steam superheaters per se F22G
• CPC Class Codes: F22B 1/028 Steam generation using heat accumulators F22B27/14 takes precedence
• CPC Class Codes: F24S 60/00 Arrangements for storing heat collected by solar heat collectors working fluids forming pools or ponds F24S10/10
• CPC Class Codes: F24S 60/30 storing heat in liquids
• CPC Class Codes: F28D 17/04 Distributing arrangements for the heat-exchange media
• 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 20/0034 using liquid heat storage material
• CPC Class Codes: F28D 20/0056 using solid heat storage material F28D20/0052 takes precedence
• CPC Class Codes: F28D 20/02 using latent heat
• CPC Class Codes: F28D 20/021 the latent heat storage material and the heat-exchanging means being enclosed in one container F28D20/023 - F28D20/028 take precedence
• CPC Class Codes: F28D 2020/0047 using molten salts or liquid metals
• CPC Class Codes: F28D 2020/0069 Distributing arrangements; Fluid deflecting means
• CPC Class Codes: F28D 2020/0082 Multiple tanks arrangements, e.g. adjacent tanks, tank in tank
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers
• 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
• CPC Class Codes: Y10S 165/902 Heat storage

Abstract

A system and method are provided for storing electric energy in the form of thermal energy. A thermoelectric energy storage system includes a working fluid circuit for circulating a working fluid through a heat exchanger, and a thermal storage medium circuit for circulating a thermal storage medium. The thermal storage medium circuit includes at least one hot storage tank, an intermediate temperature storage tank, and a cold storage tank connected together via the heat exchanger. A proportion of the storage medium is redirected to or from the intermediate storage tank from or to the hot or cold storage tank, joining another proportion which flows directly between the cold and hot storage tank.

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 heat exchanger;

a working fluid circuit for circulating a working fluid through the heat exchanger, the working fluid undergoing a transcritical process during heat transfer in the 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, an intermediate temperature storage tank and a cold storage tank connected together via the heat exchanger; and

means for modifying a rate of flow of the thermal storage medium in the heat exchanger, the means for modifying including an internal stream splitter configured to vary an input rate of flow of the thermal storage medium to the intermediate storage tank, and to vary an output rate of flow of the thermal storage medium from the intermediate storage tank,

wherein the means for modifying modifies the rate of flow of the thermal storage medium to minimize a temperature difference between the working fluid and the thermal storage medium during the charging and discharging cycles, and

wherein the internal stream splitter is comprised in the heat exchanger, and the internal stream splitter is configured to one of divide and join the stream of the thermal storage medium from the intermediate storage tank.

4. The system according to claim 1, comprising:

at least one further intermediate storage tank connected in the thermal storage medium circuit,

wherein the heat exchanger has a further internal stream splitter for each further intermediate storage tank.

5. The system according to claim 1, wherein both the charging and discharging cycle run transcritically.

9. The system according to claim 1, wherein:

the heat exchanger is divided into a first section and a second section, and the heat exchanger is configured for the thermal storage medium to flow through both the first section and the second section; and

the stream splitter is arranged between the first section and second section of the heat exchanger.

10. The system according to claim 9, wherein both the charging and discharging cycle run transcritically.

13. The system according to claim 4, wherein both the charging and discharging cycle run transcritically.

2. 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 heat exchanger;

a working fluid circuit for circulating a working fluid through the heat exchanger, the working fluid undergoing a transcritical process during heat transfer in the 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, an intermediate temperature storage tank and a cold storage tank connected together via the heat exchanger; and

means for modifying a rate of flow of the thermal storage medium in the heat exchanger, the means for modifying including an internal stream splitter configured to vary an input rate of flow of the thermal storage medium to the intermediate storage tank, and to vary an output rate of flow of the thermal storage medium from the intermediate storage tank, wherein;

the means for modifying modifies the rate of flow of the thermal storage medium to minimize a temperature difference between the working fluid and the thermal storage medium during the charging and discharging cycles;

the heat exchanger is divided into a first section and a second section, and the heat exchanger is configured for the thermal storage medium to flow through both the first section and the second section;

the internal stream splitter is arranged between the first section and second section of the heat exchanger; and

the internal stream splitter is configured to one of divide and join the stream of the thermal storage medium from the intermediate storage tank.

11. The system according to claim 2, wherein both the charging and discharging cycle run transcritically.

3. 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 heat exchanger;

a working fluid circuit for circulating a working fluid through the heat exchanger, the working fluid undergoing a transcritical process during heat transfer in the 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, an intermediate temperature storage tank and a cold storage tank connected together via the heat exchanger; and

means for modifying a rate of flow of the thermal storage medium in the heat exchanger, the means for modifying including an internal stream splitter configured to vary an input rate of flow of the thermal storage medium to the intermediate storage tank, and to vary an output rate of flow of the thermal storage medium from the intermediate storage tank,

wherein the means for modifying modifies the rate of flow of the thermal storage medium to minimize a temperature difference between the working fluid and the thermal storage medium during the charging and discharging cycles, and

wherein the heat exchanger is divided into a first section and a second section, and the heat exchanger is configured for the thermal storage medium to flow through both the first section and the second section via the intermediate storage tank.

12. The system according to claim 3, wherein both the charging and discharging cycle run transcritically.

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

circulating a thermal storage medium between a hot storage tank, an intermediate storage tank and a cold storage tank connected together via a heat exchanger;

charging the system by heating the thermal storage medium;

discharging the system by heating a working fluid in a working fluid circuit with heat from the thermal storage medium, the working fluid undergoing a transcritical process during heat transfer in the heat exchanger, and expanding the working fluid through a thermodynamic machine; and

modifying a rate of flow of the thermal storage medium through the heat exchanger by varying the input rate of flow of thermal storage medium to the intermediate storage tank, and by varying the output rate of flow of thermal storage medium from the intermediate storage tank,

wherein the step of modifying the rate of flow comprises minimizing the temperature difference between the working fluid and the thermal storage medium during the charging and discharging cycles, and

wherein the method comprises one of dividing and joining the stream of the thermal storage medium from the intermediate storage tank.

7. The method according to claim 6, comprising:

connecting at least one further intermediate storage tank via the heat exchanger; and

further one of dividing and joining the stream of the thermal storage medium for each further intermediate storage tank.

8. The method according to claim 6, wherein both the charging and the discharging cycle are performed transcritically.

15. The method according to claim 7, wherein both the charging and the discharging cycle are performed transcritically.

14. 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 heat exchanger;

a working fluid circuit for circulating a working fluid through the heat exchanger, the working fluid undergoing a transcritical process during heat transfer in the 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, an intermediate temperature storage tank and a cold storage tank connected together via the heat exchanger; and

means for modifying a rate of flow of the thermal storage medium in the heat exchanger, the means for modifying including an internal stream splitter configured to vary an input rate of flow of the thermal storage medium to the intermediate storage tank, and to vary an output rate of flow of the thermal storage medium from the intermediate storage tank, and

wherein the thermoelectric energy storage system comprises at least one of;

a plurality of intermediate storage tanks; and

a plurality of cold storage tanks.

16. The system according to claim 14, wherein both the charging and discharging cycle run transcritically.