Baffled Thermoclines in Thermodynamic Cycle Systems

• US 20180179955A1
• 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: Apte, Raj, Larochelle, Philippe
• Granted Patent: US 11,053,847 B2
• Time in Patent Office: Days
• CPC Class Codes: F02C 1/04 the working fluid being heated indirectly in a fluidised-bed combustor F02C3/205
• 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: F28D 20/0056 using solid heat storage material F28D20/0052 takes precedence
• CPC Class Codes: F28D 2020/0086 Partitions
• CPC Class Codes: F28F 13/14 by endowing the walls of conduits with zones of different degrees of conduction of heat
• CPC Class Codes: Y02E 60/14 Thermal energy storage

Abstract

Solid-state thermoclines with internal baffle structures are in used in place of heat exchangers in a closed thermodynamic cycle power generation or energy storage system, such as a closed Brayton cycle system. The baffles limit the conductive and/or radiative transfer of heat between a solid thermal medium within different zones defined by the baffle structures.

Claims

1. A thermocline vessel comprising:

an insulated pressure vessel;

an inlet for receiving a working fluid at non-atmospheric pressure;

an outlet for dispatching the working fluid at non-atmospheric pressure;

a solid thermal medium within the insulated pressure vessel and having porosity sufficient to allow the working fluid to flow through the solid thermal medium;

a plurality of baffle structures defining a plurality of zones within the insulated pressure vessel, wherein the solid thermal medium is located within the plurality of zones, wherein each baffle structure is configured to limit direct transfer of heat between the solid thermal medium in different zones; and

one or more fluid channels configured to channel the working fluid past the baffles and in contact with the solid thermal medium.

2. The thermocline vessel of claim 1, wherein the inlet receives the working fluid at the working pressure from a Brayton cycle system, and wherein the outlet dispatches the working fluid to the Brayton cycle system.

3. The thermocline vessel of claim 1, wherein the solid thermal medium is selected from the group consisting of rock, sand, dirt, gravel, clay, minerals, metal, metal oxide, ceramic, cermet, alumina, silica, refractory materials, and combinations thereof.

4. The thermocline vessel of claim 1, wherein the solid thermal medium has a form selected from the group consisting of slab, brick, platonic solid, sphere, cylinder, fabric, mesh, and combinations thereof.

5. The thermocline vessel of claim 1, wherein the working fluid within the thermocline vessel is at a pressure greater than 3 bar.

6. The thermocline vessel of claim 1, wherein the working fluid within the thermocline vessel is at a pressure less than atmospheric pressure.

7. The thermocline vessel of claim 1, wherein the working fluid is selected from the group consisting of air, argon, helium, carbon dioxide, and combinations thereof.

8. The thermocline vessel of claim 1, wherein the plurality of zones comprise an inlet zone proximate to the inlet, an outlet zone proximate to the outlet, and one or more intermediate zones disposed between the inlet zone and the outlet zone.

9. The thermocline vessel of claim 7, wherein the solid thermal medium in the inlet zone is at a first temperature, wherein the solid thermal medium in the outlet zone is at a second temperature, and wherein the solid thermal medium in each of the one or more intermediate zones is at a temperature between the first temperature and second temperature.

10. The thermocline vessel of claim 8, wherein the magnitude of the difference between the first temperature and the second temperature is greater than 200°

C.

11. The thermocline vessel of claim 1, wherein at least one of the plurality of baffle structures comprises an insulating wall extending completely across the pressure vessel, wherein the one or more fluid channels comprise a plurality of apertures through the wall.

12. The thermocline vessel of claim 1, wherein at least one of the baffle structures of the plurality of baffle structures comprises an insulating wall extending partially across an interior space of the thermocline vessel, wherein at least one of the fluid channels of the one or more fluid channels comprise a space between an end of the insulating wall and an interior wall of the pressure vessel.

13. The thermocline vessel of claim 1, wherein at least one of the baffle structures of the plurality of baffle structures comprises a perforated material extending completely across the pressure vessel, wherein the one or more fluid channels comprise perforations in the perforated material.

14. The thermocline vessel of claim 1, wherein at least one of the baffle structures of the plurality of baffle structures comprises an insulated chamber within the pressure vessel, wherein the one or more fluid channels comprise a plurality of apertures through one or more walls of the insulated chamber.

15. A system comprising:

a compressor;

a first thermocline vessel comprising a plurality of zones of a solid thermal medium defined by baffle structures in the interior of the first thermocline vessel, wherein each baffle structure is configured to limit direct transfer of heat between the solid thermal medium in different zones;

a turbine; and

a working fluid circulating, in order, through (i) the compressor, (ii) the first thermocline vessel and the solid thermal medium in the interior of the first thermocline vessel, and (iii) the turbine,

wherein the solid thermal medium within a first zone proximate to an inlet of the working fluid to the first thermocline vessel is at a first temperature, and wherein the solid thermal medium within a second zone proximate to an outlet of the working fluid from the first thermocline vessel is at a second temperature higher than the first temperature.

16. The system of claim 15, wherein the working fluid within the first thermocline vessel is at a pressure greater than atmospheric pressure.

17. The system of claim 15 further comprising:

a second thermocline vessel comprising a plurality of zones of a solid thermal medium defined by baffle structures in the interior of the second thermocline vessel, wherein each baffle structure is configured to limit direct transfer of heat between the solid thermal medium in different zones,

wherein the working fluid circulates, in order, through (i) the compressor, (ii) the first thermocline vessel and the solid thermal medium in the interior of the first thermocline vessel, (iii) the turbine, and (iv) the second thermocline vessel and the solid thermal medium in the interior of the second thermocline vessel, and

wherein the solid thermal medium within a third zone proximate to an inlet of the working fluid to the second thermocline vessel is at a third temperature, and wherein the solid thermal medium within a fourth zone proximate to an outlet of the working fluid from the second thermocline vessel is at a fourth temperature lower than the third temperature.

18. The system of claim 17 further comprising a recuperative heat exchanger configured to thermally contact the working fluid exiting the compressor with the working fluid exiting the turbine, wherein the working fluid circulates, in order, through (i) the compressor, (ii) the recuperative heat exchanger, (iii) the first thermocline vessel and the solid thermal medium in the interior of the first thermocline vessel, (iv) the turbine, (v) the recuperative heat exchanger, and (vi) the second thermocline vessel and the solid thermal medium in the interior of the second thermocline vessel.

19. The system of claim 18 further comprising a heat rejection device configured to eject from the system heat carried by the working fluid, wherein the working fluid circulates, in order, through (i) the compressor, (ii) the recuperative heat exchanger, (iii) the first thermocline vessel and the solid thermal medium in the interior of the first thermocline vessel, (iv) the turbine, (v) the recuperative heat exchanger, (vi) the heat rejection device, and (vii) the second thermocline vessel and the solid thermal medium in the interior of the second thermocline vessel.

20. An energy generation system, comprising:

a generator configured to receive mechanical energy and generate electrical energy;

a working fluid;

a compressor configured to compress the working fluid;

a turbine configured to convert expansion of the working fluid within the turbine into mechanical energy, wherein the turbine is mechanically coupled to the compressor and is configured to transmit a portion of the mechanical energy through the mechanical coupling to drive the compressor;

a recuperative heat exchanger configured to thermally contact working fluid exiting the compressor with working fluid exiting the turbine;

a cooling tower configured to eject to the atmosphere heat carried by the working fluid;

a hot-side thermocline vessel comprising a plurality of zones of a first solid thermal medium defined by baffle structures in the interior of the first thermocline vessel, wherein each baffle structure is configured to limit direct transfer of heat between the first solid thermal medium in different zones; and

a cold-side thermocline vessel comprising a plurality of zones of a second solid thermal medium defined by baffle structures in the interior of the first thermocline vessel, wherein each baffle structure is configured to limit direct transfer of heat between the second solid thermal medium in different zones,

wherein the working fluid circulates, in order, through (i) the compressor, (ii) the recuperative heat exchanger, (iii) the hot-side thermocline vessel and the first solid thermal medium in the interior of the hot-side thermocline vessel, (iv) the turbine, (v) the recuperative heat exchanger, (vi) the cooling tower, and (vii) the cold-side thermocline vessel and the second solid thermal medium in the interior of the cold-side thermocline vessel.