# US 12,111,115 B2 · Thermal energy storage system and media

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- Number: US 12,111,115 B2
- Document ID: US12111115B2
- Status: Granted
- Kind: B2
- Application number: 17/740,073
- Filed: 2022-05-09
- Published: 2022-11-24
- Granted: 2024-10-08
- Earliest claimed: 2021-05-07
- Assignees: Cratus LLC; Andrew J. Sherman
- Applicants: Cratus LLC
- Inventors: Andrew J. Sherman
- Web page: https://patentgrep.com/patent/US12111115B2

## CPC

- F28D 20/025: {the latent heat storage material being in direct contact with a heat-exchange medium or with another heat storage material (F28D20/003 takes precedence)}
- F28D 20/0043: {specially adapted for long-term heat storage; Underground tanks; Floating reservoirs; Pools; Ponds (F28D20/0052 takes precedence)}
- F28D 20/02: using latent heat
- F28D 2020/0047: {using molten salts or liquid metals}
- Y02E 60/14: Thermal energy storage
- F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The present disclosure is directed to materials that can be used in a heat storage and transfer, and an improved method for storing thermal energy which includes a high heat capacity thermal energy storage system using pumped or flowing metallic phase change materials (MPCs). Heat is added by pumping a cold fluid of MPCs mixed with a fluid media such as a molten glass and/or salt from a tank through a heat exchanger, solar receiver, or electrical heater cell and returning the heated fluid to a tank, or solid MPCs can be transported physically, or via gas transport such as entrained flow or a circulating fluid bed. In the heat exchanger, heat can optionally be transferred directly to a counterflowing gas or other fluid, or indirectly through heat exchanger walls to a working fluid, which can be steam, CO2 or sCO2, He, H2, process gas, and/or heat transfer fluid. The MPCs (encapsulated MPCs, non-coated MPCs) are solid-liquid and/or solid-solid phase change particles, salts, metals, or other compounds with a melting point between the hot and cold fluid temperatures, and can optionally include high heat capacity, and/or energy absorbing (IR and divisible) nanoparticles.

## Claims

### Claim 1

A thermal energy storage system which includes:
a. a storage tank;
b. a thermal fluid; said thermal fluid includes i) glass and/or salt; and ii) a metallic phase change material (MPC); said MPC is mixed with said thermal fluid to form a thermal mixture; said MPC includes an encapsulated metallic mixture having a melting temperature or range that falls within a temperature range of 400-1500° C.; wherein the MPC includes a core and coating; said core is formulated to have a liquidus temperature of 550-750° C.; said MPC is formulated to be reusable to a temperature of at least 700° C.

### Claim 2 (depends on 1)

The thermal energy storage system as defined in claim 1, wherein the MPC has a particle size of 20-2000 microns.

### Claim 3 (depends on 1)

The thermal energy storage system as defined in claim 1, wherein said MPC includes a core and coating; said MPC formulated to be reusable to a temperature of 800-1200° C.

### Claim 4 (depends on 1)

The thermal energy storage system as defined in claim 1, wherein said thermal fluid includes a eutectic salt or near eutectic salt, or a eutectic glass or near eutectic glass.

### Claim 5 (depends on 1)

The thermal energy storage system as defined in claim 1, wherein the salt includes one or more of a) sodium nitrate/potassium nitrate, b) a ternary salt mixture of NaNO3/KNO3/NaNO2, c) carbonate and fluoride salts, d) LiNaK fluorides, e) ZnNaK chlorides, f) MgNaK chlorides, g) AlCl3—NaCl—KCl, h) ZnCl2—NaCl—KCl, i) FeCl3—NaCl—KCl, j) NaCl—CaCl2—MgCl2, and/or k) KCl—NaCl—CaCl2—MgCl2; the glass is a phosphate or borate low melting point glass.

### Claim 6 (depends on 1)

The thermal energy storage system as defined in claim 1, wherein said thermal mixture includes 5-80 vol. % MPC and 20-95 vol. % salt and/or glass.

### Claim 7 (depends on 1)

The thermal energy storage system as defined in claim 1, wherein said MPC has a size having at least one dimension that is from 20-5000 microns.

### Claim 8

A thermal energy storage system which includes:
a. a storage tank;
b. a thermal fluid; said thermal fluid includes i) glass and/or salt; and ii) a metallic phase change material (MPC); said MPC is mixed with said thermal fluid to form a thermal mixture; said MPC includes an encapsulated metallic mixture having a melting temperature or range that falls within a temperature range of 400-1500° C.; said MPC is formulated to be reusable in a temperature environment of at least 400° C.; said thermal mixture further includes 0.5-10 vol. % colloidal nanoparticles.

### Claim 9 (depends on 8)

The thermal energy storage system as defined in claim 8, wherein said colloidal nanoparticles include one or more metals, metal oxides, and/or non-metal oxides; said colloidal nanoparticles have at least one dimension that is no more than 200 nm.

### Claim 10 (depends on 8)

The thermal energy storage system as defined in claim 8, wherein said colloidal nanoparticles include one or more materials selected from the group consisting of SiO2, ZnO, Al2O3, TiO2, MgO, Fe2O3, BaTiO3, Ce2O3, ZrO2, CaO, Ni, Mo, Si, Re, Nb, Ta, W, Au, and Ag.

### Claim 11

A thermal energy storage system which includes:
a. a storage tank;
b. a thermal fluid; said thermal fluid includes i) glass and/or salt; and ii) a metallic phase change material (MPC); said MPC is mixed with said thermal fluid to form a thermal mixture; said MPC includes an encapsulated metallic mixture having a melting temperature or range that falls within a temperature range of 400-1500° C.; said MPC includes a core and coating; said core is formulated to have a liquidus temperature above 400° C.; said MPC is formulated to be reusable in a temperature environment of at least 800° C.; said MPC includes at least 50 wt. % Si metal.

### Claim 12

A thermal energy storage system which includes:
a. a storage tank;
b. a thermal fluid; said thermal fluid includes i) glass and/or salt; and ii) a metallic phase change material (MPC); said MPC is mixed with said thermal fluid to form a thermal mixture; said MPC includes an encapsulated metallic mixture having a melting temperature or range that falls within a temperature range of 400-1500° C.; said MPC is formulated to be reusable in a temperature environment of at least 400° C.; said MPC has a latent heat of at least 300 J/g.

### Claim 13

A thermal energy storage system which includes:
a. a storage tank;
b. a thermal fluid; said thermal fluid includes i) glass and/or salt; and ii) a metallic phase change material (MPC); said MPC is mixed with said thermal fluid to form a thermal mixture; said MPC includes an encapsulated metallic mixture having a melting temperature or range that falls within a temperature range of 400-1500° C.; said MPC is formulated to be reusable in a temperature environment of at least 400° C.; said MPC has a latent heat that falls within the range of 300-2000 J/g.

### Claim 14

A thermal energy storage system which includes:
a. a storage tank;
b. a thermal fluid; said thermal fluid includes i) glass and/or salt; and ii) a metallic phase change material (MPC); said MPC is mixed with said thermal fluid to form a thermal mixture; said MPC includes an encapsulated metallic mixture having a melting temperature or range that falls within a temperature range of 400-1500° C.; said MPC is formulated to be reusable in a temperature environment of at least 400° C.; said MPC includes a) Si-(A and/or B) MPC; b) Si-(A and/or B)-(X) MPC; and/or c) Si-(A and/or B)-(X and Y); said A, B, X and Y are elements; said elements for A and B are selected from the group consisting of aluminum, copper, boron, germanium, and magnesium; said elements for X and Y are selected from the group consisting of aluminum, calcium, chromium, cobalt, copper, iron, magnesium, manganese, and nickel.

### Claim 15

A thermal energy storage system which includes:
a. a storage tank;
b. a thermal fluid; said thermal fluid includes i) glass and/or salt; and ii) a metallic phase change material (MPC); said MPC is mixed with said thermal fluid to form a thermal mixture; said MPC includes an encapsulated metallic mixture having a melting temperature or range that falls within a temperature range of 400-1500° C.; said MPC is formulated to be reusable in a temperature environment of at least 400° C.; said MPC includes one or more materials selected from the group consisting of Si—Al, Si—Mg—Cu, Si—Mg, Si—Al—Ca, Si—Cu—Ca, Si—Ge, Si—B, Si—Ge—B, Si—Ge—Fe, Si—Ge—Mn, Si—Ge—Fe—Mn, Si—Ge—Cu, Si—Ge—Ni, Si—Ge—Cr, Si—Ge—Cu—Fe, Si—Ge—Ni—Fe, and Si—Ge—Cr—Fe.

### Claim 16

A thermal energy storage system which includes:
a. a storage tank;
b. a thermal fluid; said thermal fluid includes i) glass and/or salt; and ii) a metallic phase change material (MPC); said MPC is mixed with said thermal fluid to form a thermal mixture; said MPC includes an encapsulated metallic mixture having a melting temperature or range that falls within a temperature range of 400-1500° C.; said MPC is formulated to be reusable in a temperature environment of at least 400° C.; said MPC includes at least 10 wt. % Si; and one or more of a) at least 10 wt. % Al, b) at least 10 wt. % B; c) at least 10 wt. % Cu, d) at least 10 wt. % Ge, and e) at least 10 wt. % Mg.

### Claim 17

A thermal energy storage system which includes:
a. a storage tank;
b. a thermal fluid; said thermal fluid includes i) glass and/or salt; and ii) a metallic phase change material (MPC); said MPC is mixed with said thermal fluid to form a thermal mixture; said MPC includes an encapsulated metallic mixture having a melting temperature or range that falls within a temperature range of 400-1500° C.; said MPC is formulated to be reusable in a temperature environment of at least 400° C.; said MPC includes an outer coating; said outer coating includes one or more materials selected from the group consisting of SiC, SiOCN, SiCN, Si3N4, SiB6, TiO2, and an organic polysilizane preceramic polymer.

### Claim 18 (depends on 17)

The thermal energy storage system as defined in claim 17, wherein said coating includes filler; said filler including one or more materials selected from the group consisting of carbon fibers, boron fibers, ceramic spheres, carbon powders, TiO2, SiC powder, Boron nitride, and B4C.

### Claim 19 (depends on 17)

The thermal energy storage system as defined in claim 17, wherein said coating has a thickness of 1 to 500 microns.

### Claim 20

A thermal energy storage system which includes:
a. a storage tank; and,
b. a thermal fluid; said thermal fluid includes i) glass and/or salt; and ii) a metallic phase change material (MPC); said MPC is mixed with said thermal fluid to form a thermal mixture; said thermal mixture includes 5-80 vol. % MPC and 20-95 vol. % salt and/or glass; said thermal fluid includes a ternary salt, a quaternary salt, and/or a quinary salt; said MPC includes a) Si-(A and/or B) MPC; b) Si-(A and/or B)-(X) MPC; and/or c) Si-(A and/or B)-(X and Y); said A, B, X and Y are elements; said elements for A and B are selected from the group consisting of aluminum, copper, boron, germanium, and magnesium; said elements for X and Y are selected from the group consisting of aluminum, calcium, chromium, cobalt, copper, iron, magnesium, manganese, and nickel; said MPC includes an encapsulated metallic mixture having a melting temperature of 400-1500° C.; said MPC is formulated to be reusable in a temperature environment of at least 400° C.; said MPC has a particle size of 20-5000 microns; said MPC has a latent heat of at least 300 J/g.

### Claim 21 (depends on 20)

The thermal energy storage system as defined in claim 20, wherein said MPC includes a core and a coating; said core is formulated to have a liquidus temperature of greater than 400° C.

### Claim 22 (depends on 21)

The thermal energy storage system as defined in claim 21, wherein said coating; said outer coating includes one or more materials selected from the group consisting of SiC, SiOCN, SiCN, Si3N4, SiB6, TiO2, and an organic polysilizane preceramic polymer; said coating has a thickness of 1 to 500 microns.

### Claim 23 (depends on 21)

The thermal energy storage system as defined in claim 21, wherein said coating includes filler; said filler includes one or more materials selected from the group consisting of carbon fibers, boron fibers, ceramic spheres, carbon powders, TiO2, SiC powder, boron nitride, and B4C.

### Claim 24 (depends on 20)

The thermal energy storage system as defined in claim 20, wherein said thermal fluid includes a eutectic salt or near eutectic salt, or a eutectic glass or near eutectic glass; said eutectic salt or near eutectic salt includes one or more of a) sodium nitrate/potassium nitrate, b) a ternary salt mixture of NaNO3/KNO3/NaNO2, c) carbonate and fluoride salts, d) LiNaK fluorides, e) ZnNaK chlorides, f) MgNaK chlorides, g) AlCl3—NaCl—KCl, h) ZnCl2—NaCl—KCl, i) FeCl3—NaCl—KCl, j) NaCl—CaCl2—MgCl2, and/or k) KCl—NaCl—CaCl2—MgCl2; said eutectic glass or near eutectic glass is a phosphate or borate low melting point glass.

### Claim 25 (depends on 21)

The thermal energy storage system as defined in claim 21, wherein said thermal fluid includes a eutectic salt or near eutectic salt, or a eutectic glass or near eutectic glass; said eutectic salt or near eutectic salt includes one or more of a) sodium nitrate/potassium nitrate, b) a ternary salt mixture of NaNO3/KNO3/NaNO2, c) carbonate and fluoride salts, d) LiNaK fluorides, e) ZnNaK chlorides, f) MgNaK chlorides, g) AlCl3—NaCl—KCl, h) ZnCl2—NaCl—KCl, i) FeCl3—NaCl—KCl, j) NaCl—CaCl2—MgCl2, and/or k) KCl—NaCl-CaCl2—MgCl2; said eutectic glass or near eutectic glass is a phosphate or borate low melting point glass.

### Claim 26 (depends on 20)

The thermal energy storage system as defined in claim 20, wherein said thermal mixture further includes 0.5-10 vol. % colloidal nanoparticles; said colloidal nanoparticles include one or more metals, metal oxides, and/or non-metal oxides; said colloidal nanoparticles have at least one dimension that is no more than 200 nm.

### Claim 27 (depends on 25)

The thermal energy storage system as defined in claim 25, wherein said thermal mixture further includes 0.5-10 vol. % colloidal nanoparticles; said colloidal nanoparticles include one or more metals, metal oxides, and/or non-metal oxides; said colloidal nanoparticles have at least one dimension that is no more than 200 nm.

### Claim 28 (depends on 26)

The thermal energy storage system as defined in claim 26, wherein said colloidal nanoparticles include one or more materials selected from the group consisting of SiO2, ZnO, Al2O3, TiO2, MgO, Fe2O3, BaTiO3, Ce2O3, ZrO2, CaO, Ni, Mo, Si, Re, Nb, Ta, W, Au, and Ag.

### Claim 29 (depends on 20)

The thermal energy storage system as defined in claim 20, wherein said MPC includes one or more materials selected from the group consisting of Si—Al, Si—Mg—Cu, Si—Mg, Si—Al—Ca, Si—Cu—Ca, Si—Ge, Si—B, Si—Ge—B, Si—Ge—Fe, Si—Ge—Mn, Si—Ge—Fe—Mn, Si—Ge—Cu, Si—Ge—Ni, Si—Ge—Cr, Si—Ge—Cu—Fe, Si—Ge—Ni—Fe, and Si—Ge—Cr—Fe.

### Claim 30 (depends on 27)

The thermal energy storage system as defined in claim 27, wherein said MPC includes one or more materials selected from the group consisting of Si—Al, Si—Mg—Cu, Si—Mg, Si—Al—Ca, Si—Cu—Ca, Si—Ge, Si—B, Si—Ge—B, Si—Ge—Fe, Si—Ge—Mn, Si—Ge—Fe—Mn, Si—Ge—Cu, Si—Ge—Ni, Si—Ge—Cr, Si—Ge—Cu—Fe, Si—Ge—Ni—Fe, and Si—Ge—Cr—Fe.

### Claim 31 (depends on 29)

The thermal energy storage system as defined in claim 29, wherein said MPC includes at least 50 wt. % Si metal.

### Claim 32 (depends on 20)

The thermal energy storage system as defined in claim 20, wherein said MPC includes at least 10 wt. % Si; and one or more of a) at least 10 wt. % Al, b) at least 10 wt. % B; c) at least 10 wt. % Cu, d) at least 10 wt. % Ge, and e) at least 10 wt. % Mg.

### Claim 33 (depends on 30)

The thermal energy storage system as defined in claim 30, wherein said MPC includes at least 10 wt. % Si; and one or more of a) at least 10 wt. % Al, b) at least 10 wt. % B; c) at least 10 wt. % Cu, d) at least 10 wt. % Ge, and e) at least 10 wt. % Mg.

### Claim 34 (depends on 20)

The thermal energy storage system as defined in claim 20, wherein said MPC includes at least 20 wt. % Si and one or more alloying elements selected from the group consisting of Al, Mg, Ge, Fe, Ni, Cu, Mn, and Cr.

### Claim 35 (depends on 30)

The thermal energy storage system as defined in claim 30, wherein said MPC includes at least 20 wt. % Si and one or more alloying elements selected from the group consisting of Al, Mg, Ge, Fe, Ni, Cu, Mn, and Cr.

### Claim 36 (depends on 34)

The thermal energy storage system as defined in claim 34, wherein said MPC includes 20-80 wt. % Si, and 20-80 wt. % of one or more of Al, Mg, Ge, Fe, Ni, Cu, Mn, and Cr.

### Claim 37 (depends on 36)

The thermal energy storage system as defined in claim 36, wherein said MPC two or more of Al, Mg, Ge, Fe, Ni, Cu, Mn, and Cr.

### Claim 38 (depends on 34)

The thermal energy storage system as defined in claim 34, wherein said MPC includes 1-25 wt. % of B.