# US 5,347,828 A · Organic hydride/metal hydride heat pump

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,347,828 A
- Document ID: US5347828A
- Status: Granted
- Kind: A
- Application number: 08/083,824
- Filed: 1993-06-25
- Granted: 1994-09-20
- Earliest claimed: 1993-03-23
- Assignees: United Technologies Corporation
- Inventors: Arthur S. Kesten
- Web page: https://patentgrep.com/patent/US5347828A

## CPC

- F25B 17/12: using desorption of hydrogen from a hydride
- F17C 11/005: {for hydrogen}
- F28D 20/003: {using thermochemical reactions}
- Y02E 60/14: Thermal energy storage
- Y02E 60/32: Hydrogen storage
- Y02P 20/129: Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
- F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F17C: VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES (storing fluids in natural or artificial cavities or chambers in the earth B65G5/00; construction or assembling of bulk storage containers employing civil-engineering techniques E04H7/00; variable-capacity gas-holders F17B; liquefaction or refrigeration machines, plants, or systems F25)
- 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
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A heat pump that includes organic hydride (12) and metal hydride (2) systems cools a conditioned space (6) by transferring heat from the conditioned space to a metal hydride bed (4), thereby decomposing a metal hydride in the bed to form H.sub.2. The H.sub.2 flows to a vapor space (14) in the liquid hydride system (12) and reacts with a dehydrogenation product at a catalytic surface (32) in the vapor space to form an organic hydride and an exothermic heat of reaction. The heat pump also may be used to upgrade waste heat by transferring heat from a relatively low temperature heat source to decompose the metal hydride. The exothermic heat of reaction may then be removed from the vapor space and used for space heating. In both embodiments, the metal hydride bed (4) may be regenerated by supplying an endothermic heat of reaction to the catalytic surface (32), thereby dehydrogenating the organic hydride to form H.sub.2. The H.sub.2 flows to the metal hydride bed (4) and reacts with the metal hydride bed to regenerate the metal hydride. Alternately, the metal hydride bed (4) may be regenerated by flowing a liquid mixture that includes the organic hydride into a reaction zone (38) having a dehydrogenation catalyst (42) and supplying an endothermic heat of reaction to the reaction zone, thereby dehydrogenating the organic hydride to form H.sub.2. As before, the H.sub.2 flows to the metal hydride bed (4) where it regenerates the metal hydride.

## Claims

### Claim 1

A heat pump, comprising:
(a) an organic hydride system that comprises:
(i) a vessel having a liquid space and a vapor space,
(ii) a catalytic surface disposed in the vapor space, wherein the catalytic surface promotes dehydrogenation of an organic hydride to form H.sub.2 and hydrogenation of an organic dehydrogenation product to form the organic hydride,
(iii) means for heating the catalytic surface when the catalytic surface promotes dehydrogenation, and
(iv) means for cooling the catalytic surface when the catalytic surface promotes hydrogenation,
(b) a metal hydride system that comprises:
(i) a metal hydride bed,
(ii) means for transferring heat from a heat source to the metal hydride bed, and
(c) a duct connecting the vapor space of the organic hydride system with the metal hydride system.

### Claim 2 (depends on 1)

The device of claim 1, further comprising means for circulating a liquid mixture that comprises the organic hydride through the metal hydride system to remove heat from the metal hydride bed.

### Claim 3 (depends on 1)

The device of claim 1, wherein the catalytic surface comprises Ni, Cr, Co, Pt, Ru, Rh, Re, Ir, or Pd.

### Claim 4 (depends on 1)

The device of claim 1, wherein the organic hydride comprises a hydrocarbon or alcohol.

### Claim 5 (depends on 4)

The device of claim 4, wherein the organic hydride comprises up to about 14 carbon atoms.

### Claim 6 (depends on 5)

The device of claim 5, wherein the organic hydride comprises methylcyclohexane or 2-propanol.

### Claim 7 (depends on 1)

The device of claim 1, wherein the metal hydride dissociates to hydrogen at a temperature above about 10.degree. C.

### Claim 8 (depends on 7)

The device of claim 7, wherein the metal hydride comprises La or Ni.

### Claim 9

A heat pump, comprising:
(a) an organic hydride system that comprises:
(i) a vessel having a liquid space and a vapor space,
(ii) a catalytic surface disposed in the vapor space, wherein the catalytic surface promotes hydrogenation of an organic dehydrogenation product to form an organic hydride,
(iii) means for cooling the catalytic surface when the catalytic surface promotes hydrogenation,
(iv) a liquid-phase reaction zone in fluid communication with the liquid space,
(v) a dehydrogenation catalyst disposed in the reaction zone, wherein the dehydrogenation catalyst promotes dehydrogenation of the organic hydride to form H.sub.2,
(vi) means for providing an endothermic heat of reaction to the reaction zone, and
(vii) means for transporting H.sub.2 from the reaction zone to the vapor space,
(b) a metal hydride system that comprises:
(i) a metal hydride bed,
(ii) means for transferring heat from a heat source to the metal hydride bed,
(iii) means for circulating a liquid mixture that comprises the organic hydride through the metal hydride system to remove heat from the metal hydride bed, and
(c) a duct connecting the vapor space of the organic hydride system with the metal hydride system.

### Claim 10 (depends on 9)

The device of claim 9, wherein the catalytic surface comprises Ni, Cr, Co, Pt, Ru, Rh, Re, Ir, or Pd.

### Claim 11 (depends on 9)

The device of claim 9, wherein the dehydrogenation catalyst comprises a carbon support and at least one of Pt, Ru, Rh, Re, Ir, or Pd disposed on the carbon support.

### Claim 12 (depends on 9)

The device of claim 9, wherein the organic hydride comprises a hydrocarbon or alcohol.

### Claim 13 (depends on 12)

The device of claim 12, wherein the organic hydride comprises up to about 14 carbon atoms.

### Claim 14 (depends on 13)

The device of claim 13, wherein the organic hydride comprises methylcyclohexane or 2-propanol.

### Claim 15 (depends on 9)

The device of claim 9, wherein the metal hydride dissociates to hydrogen at a temperature above about 10.degree. C.

### Claim 16 (depends on 15)

The device of claim 15, wherein the metal hydride comprises La or Ni.

### Claim 17

A method of cooling a heat source with a heat pump that includes a metal hydride system and an organic hydride system, comprising the step of:
(a) operating the device in a primary mode that comprises:
(i) transferring heat from a heat source to a metal hydride bed, thereby cooling the heat source and decomposing a metal hydride in the bed to form H.sub.2,
(ii) flowing the H.sub.2 to a vapor space in a liquid hydride system, and
(iii) reacting the H.sub.2 with a dehydrogenation product at a catalytic surface in the vapor space to form an organic hydride and an exothermic heat of reaction.

### Claim 18 (depends on 17)

The method of claim 17, wherein the heat source is a conditioned space.

### Claim 19 (depends on 17)

The method of claim 17, wherein the exothermic heat of reaction is removed from the vapor space and used for space heating.

### Claim 20 (depends on 17)

The method of claim 17, wherein the metal hydride dissociates to hydrogen at a temperature above about 10.degree. C.

### Claim 21 (depends on 20)

The method of claim 20, wherein the metal hydride comprises La or Ni.

### Claim 22 (depends on 17)

The method of claim 17, wherein the dehydrogenation product comprises a dehydrogenation product of a hydrocarbon or alcohol.

### Claim 23 (depends on 22)

The method of claim 22, wherein the dehydrogenation product comprises up to about 14 carbon atoms.

### Claim 24 (depends on 23)

The method of claim 23, wherein the dehydrogenation product comprises toluene or acetone.

### Claim 25 (depends on 17)

The method of claim 17, wherein the catalytic surface comprises Ni, Cr, Co, Pt, Ru, Rh, Re, Ir, or Pd.

### Claim 26 (depends on 17)

The method of claim 17, further comprising the step of:
(b) operating the device in a regeneration mode that comprises:
(i) supplying an endothermic heat of reaction to the catalytic surface, thereby dehydrogenating the organic hydride to form H.sub.2 ,
(ii) flowing the H.sub.2 to the metal hydride bed, and
(iii) reacting the H.sub.2 with the metal hydride bed to regenerate the metal hydride and produce an exothermic heat of reaction.

### Claim 27 (depends on 26)

The method of claim 26 wherein the organic hydride is dehydrogenated at a temperature between about 100.degree. C. and about 500.degree. C.

### Claim 28 (depends on 26)

The method of claim 26, wherein the exothermic heat of reaction is removed from the metal hydride bed with liquid organic hydride.

### Claim 29 (depends on 17)

The method of claim 17, further comprising the step of:
(b) operating the device in a regeneration mode that comprises:
(i) flowing a liquid mixture that comprises the organic hydride into a reaction zone that includes a dehydrogenation catalyst,
(ii) supplying an endothermic heat of reaction to the reaction zone, thereby dehydrogenating the organic hydride to form H.sub.2,
(iii) flowing the H.sub.2 to the metal hydride bed, and
(iv) reacting the H.sub.2 with the metal hydride bed to regenerate the metal hydride and produce an exothermic heat of reaction.

### Claim 30 (depends on 29)

The method of claim 29, wherein the dehydrogenation catalyst comprises a carbon support and at least one of Pt, Ru, Rh, Re, Ir, or Pd disposed on the carbon support.

### Claim 31 (depends on 29)

The method of claim 29, where in the organic hydride is dehydrogenated at a temperature of about the boiling point of the organic hydride.