# US 11,306,237 B2 · Latent-heat storage material composition and latent-heat storage tank

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- Number: US 11,306,237 B2
- Document ID: US11306237B2
- Status: Granted
- Kind: B2
- Application number: 16/487,871
- Filed: 2018-02-19
- Published: 2020-07-30
- Granted: 2022-04-19
- Earliest claimed: 2017-03-13
- Assignees: Toho Gas Co., Ltd.
- Applicants: Toho Gas Co., Ltd.
- Inventors: Kohei Nakamura; Takashi Ina
- Web page: https://patentgrep.com/patent/US11306237B2

## CPC

- C09K 5/063: {Materials absorbing or liberating heat during crystallisation; Heat storage materials}
- C09K 5/06: the change of state being from liquid to solid or vice versa
- F28D 20/00: Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
- F28D 20/02: using latent heat
- F28F 23/02: Arrangements for obtaining or maintaining same in a liquid state
- Y02E 60/14: Thermal energy storage
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- 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)
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A latent-heat storage material composition includes: a latent-heat storage material for storing or releasing heat by utilizing absorption or release of latent heat in association with phase change; and additives mixed with the latent-heat storage material. The additives can adjust a property of the latent-heat storage material. The additives include a first additive, which is a water-soluble substance belonging to polysaccharides and is gellan gum, which is also a thickener for increasing the viscosity of a melt of the latent-heat storage material composition in a liquid phase state, based on interaction of the thickener with water contained in the latent-heat storage material composition and cations. The content of the gellan gum is 1 wt % or less of the weight of the whole latent-heat storage material composition.

## Claims

### Claim 1

A latent-heat storage material composition in which a latent-heat storage material capable of storing heat or releasing heat utilizing absorption or release of latent heat in association with phase change is mixed with an additive capable of adjusting a property of the latent-heat storage material, the latent-heat storage material composition comprising the latent-heat storage material, water, and the additive,
wherein the additive comprises at least a first additive that is a water-soluble substance belonging to a polysaccharide and is a thickener to increase viscosity of a melt of the latent-heat storage material composition in a state of a liquid phase based on interaction of the thickener with water and a cation included in the latent-heat storage material composition,
wherein the first additive is dissolved in the water included in the latent-heat storage material composition to have a random coil structure when the latent-heat storage material composition is in a temperature range of a state of a liquid phase, while, when the latent-heat storage material composition is in a temperature range before changing from the state of a liquid phase to a state of a complete solid phase, the structure of the first additive changes into a double spiral structure reversible from the random coil structure and also the first additive has a property to cause gelation by assembly of the double spiral structures next to each other based on presence of the cation in the latent-heat storage material composition, and
wherein a mixing amount of the first additive relative to a whole weight of the latent-heat storage material composition is 1 wt % or less.

### Claim 2 (depends on 1)

The latent-heat storage material composition according to claim 1,
wherein the latent-heat storage material composition is packed in a container, and is used by repeating a heat storage and release cycle several times by phase change between a liquid phase and a solid phase with the latent-heat storage material composition packed in the container.

### Claim 3 (depends on 1)

The latent-heat storage material composition according to claim 1, wherein a main component of the latent-heat storage material is alum hydrate.

### Claim 4 (depends on 3)

The latent-heat storage material composition according to claim 3, wherein the alum hydrate is either ammonia alum dodecahydrate (AlNH4(SO4)2·12H2O) or potassium alum dodecahydrate (AlK(SO4)2·12H2O).

### Claim 5 (depends on 4)

The latent-heat storage material composition according to claim 4, wherein the additive further comprises a second additive, different from the first additive, wherein the second additive is a melting point modifier to adjust a melting point of the latent-heat storage material and is a substance having a property to generate negative dissolution heat upon being dissolved in the latent-heat storage material.

### Claim 6 (depends on 3)

The latent-heat storage material composition according to claim 3, wherein the cation in the latent-heat storage material composition is a positive ion provided by the alum hydrate.

### Claim 7 (depends on 6)

The latent-heat storage material composition according to claim 6, wherein the additive further comprises a second additive, different from the first additive, wherein the second additive is a melting point modifier to adjust a melting point of the latent-heat storage material and is a substance having a property to generate negative dissolution heat upon being dissolved in the latent-heat storage material.

### Claim 8 (depends on 3)

The latent-heat storage material composition according to claim 3, wherein the additive further comprises a second additive, different from the first additive, wherein the second additive is a melting point modifier to adjust a melting point of the latent-heat storage material and is a substance having a property to generate negative dissolution heat upon being dissolved in the latent-heat storage material.

### Claim 9 (depends on 1)

The latent-heat storage material composition according to claim 1, wherein the additive further comprises a second additive, different from the first additive, wherein the second additive is a melting point modifier to adjust a melting point of the latent-heat storage material and is a substance having a property to generate negative dissolution heat upon being dissolved in the latent-heat storage material.

### Claim 10 (depends on 1)

The latent-heat storage material composition according to claim 1, wherein the latent-heat storage material composition is formed in a state in which separation of components of the latent-heat storage material composition due to a difference in density is prevented by the first additive.

### Claim 11 (depends on 1)

The latent-heat storage material composition according to claim 1, wherein the first additive is gellan gum.

### Claim 12 (depends on 1)

The latent-heat storage material composition according to claim 1, wherein the first additive is a polymer compound formed by linking a plurality of monosaccharide molecules, which may be the same or different, and includes at least one hydrophilic group.

### Claim 13 (depends on 12)

The latent-heat storage material composition according to claim 12, wherein the at least one hydrophilic group is a carboxy group.

### Claim 14 (depends on 1)

A latent-heat storage tank equipped with a latent-heat storage material composition in which a latent-heat storage material capable of storing heat or releasing heat utilizing absorption or release of latent heat in association with phase change is mixed with an additive capable of adjusting a property of the latent-heat storage material, a heat medium which is a medium to transfer heat from/to the latent-heat storage material composition, and a dividing member to divide the latent-heat storage material composition and the heat medium in the inner part thereof,
wherein the latent-heat storage material composition is a latent-heat storage material composition according to claim 1.