# US 2018/0320987 A1 · Thermal storage units, components thereof, and methods of making and using them > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0320987 A1 - Document ID: US20180320987A1 - Status: Published application - Kind: A1 - Application number: 16/030,160 - Filed: 2018-07-09 - Published: 2018-11-08 - Earliest claimed: 2013-08-29 - Assignees: Board of Regents, The University of Texas System - Applicants: Board of Regents, the University of Texas System - Inventors: Alexandre K. Da Silva; Evan Fleming; Li Shi; Christopher W. Bielawski; Rodney S. Ruoff; Shaoyi Wen; Hengxing Ji; Michael Pettes; Abhijit Paul; Eunsu Paek; Alexander J. Pak; Daniel P. Sellan - Web page: https://patentgrep.com/patent/US20180320987A1 ## CPC - F28D 20/021: {the latent heat storage material and the heat-exchanging means being enclosed in one container (F28D20/023 - F28D20/028 take precedence)} - B60L 53/38: specially adapted for charging by inductive energy transfer - C01B 32/16: Preparation - C09K 5/063: {Materials absorbing or liberating heat during crystallisation; Heat storage materials} - C23C 16/44: characterised by the method of coating (C23C16/04 takes precedence) - F28D 7/082: {with serpentine or zig-zag configuration} - F28D 20/023: {the latent heat storage material being enclosed in granular particles or dispersed in a porous, fibrous or cellular structure} - F28F 13/003: {by using permeable mass, perforated or porous materials (F28F13/18 takes precedence)} - B60L 2270/44: Heat storages, e.g. for cabin heating - C01B 2202/24: Thermal properties - C01B 2202/34: Length - C01B 2202/36: Diameter - H01M 4/625: {Carbon or graphite} - Y02E 60/10: Energy storage using batteries - Y02E 60/14: Thermal energy storage - Y02T 10/70: Energy storage systems for electromobility, e.g. batteries - Y02T 10/7072: Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors - Y02T 90/12: Electric charging stations - Y02T 90/14: Plug-in electric vehicles - 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) - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16) - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract Sugar alcohol blends of galactitol and mannitol and compositions comprising such blends are disclosed as phase change materials (PCMs). A method of forming carbon nanotubes on a carbon substrate is described. Carbon substrates with carbon nanotubes, in particular, conformal layers of carbon nanotubes on carbon substrates, are also disclosed, as are methods of making and using these materials. Thermal storage units are also provided. The thermal storage units can comprise a heat exchange path through which a heat exchange medium flows, and a thermal storage medium in thermal contact with the heat exchange path. ## Claims ### Claim 1 A composition comprising galactitol and mannitol in a weight ratio of from about 9:1 to about 1:9. ### Claim 2 (depends on 1) The composition of claim 1, wherein the weight ratio of galactitol to mannitol is from about 2.5:1 to about 1:1.5. ### Claim 3 (depends on 1, 2) The composition of any of claims 1-2, wherein the weight ratio of galactitol to mannitol is about 1:1. ### Claim 4 (depends on 1, 2, 3) The composition of any of claims 1-3, wherein the amount of galactitol and mannitol is at least about 75 wt. % of the total composition. ### Claim 5 (depends on 1, 2, 3, 4) The composition of any of claims 1-4, wherein the amount of galactitol and mannitol is at least about 90 wt. % of the total composition. ### Claim 6 (depends on 1, 2, 3, 4, 5) The composition of any of claims 1-5, wherein the amount of galactitol and mannitol is at least about 98 wt. % of the total composition. ### Claim 7 (depends on 1, 2, 3, 4, 5, 6) The composition of any of claims 1-6, wherein the composition has a melting point of from about 150° C. to about 160° C. ### Claim 8 (depends on 1, 2, 3, 4, 5, 6, 7) The composition of any of claims 1-7, wherein the composition has a melting point of from about 151° C. to about 153° C. ### Claim 9 (depends on 1, 2, 3, 4, 5, 6, 7, 8) The composition of any of claims 1-8, wherein the composition has a latent heat of fusion of from about 280 J/g to about 315 J/g. ### Claim 10 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9) The composition of any of claims 1-9, wherein the composition has a melting point of from about 300 J/g to about 310 J/g. ### Claim 11 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10) The composition of any of claims 1-10, wherein the galactitol and/or mannitol is oxidized, reduced, or functionalized with an alkyl, amino, amido, cyano, thio, or ester group at one or more positions. ### Claim 12 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11) The composition of any of claims 1-11, further comprising one or more of a viscosity modifier, an antimicrobial material, a fire retardant, an agent to prevent supercooling, a thickener, an antioxidant, or a corrosion inhibitor. ### Claim 13 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) The composition of any of claims 1-12, further comprising one or more thermal storage materials selected from the group consisting of fatty acid, paraffin, polyethylene glycol, polyvinyl alcohol, glycerin, polyethylene, and crosslinked polyethylene. ### Claim 14 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13) A microcapsule comprising the composition of any of claims 1-13. ### Claim 15 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13) A thermal composite comprising the composition of any of claims 1-13 and a thermal conductivity modulator. ### Claim 16 (depends on 15) The thermal composite of claim 15, wherein the thermal conductivity modulator comprises a metal or metal oxide. ### Claim 17 (depends on 15) The thermal composite of claim 15, wherein the thermal conductivity modulator comprises a graphitic foam. ### Claim 18 (depends on 15) The thermal composite of claim 15, wherein the graphitic foam is a hybrid ultrathin graphitic foam comprising nanotubes. ### Claim 19 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18) A thermal storage device comprising the composition of any of claims 1-13, the microcapsule of claim 14, or the thermal composite of any of claims 15-18. ### Claim 20 (depends on 19) The thermal storage device of claim 19, wherein the device is a shell tube device. ### Claim 21 A method of forming carbon nanotubes on a carbon substrate, comprising: a. depositing a buffer layer on the carbon substrate by atomic layer deposition; b. depositing a catalyst on the carbon substrate and/or buffer layer; and c. contacting the carbon substrate with a working gas at an elevated temperature to thereby form carbon nanotubes on the carbon substrate. ### Claim 22 (depends on 21) The method of claim 21, wherein step a) is performed before step b). ### Claim 23 (depends on 21) The method of claim 21, wherein step b) is performed before step a). ### Claim 24 (depends on 21, 22, 23) The method of any of claims 21-23, wherein the carbon substrate is a carbon foam. ### Claim 25 (depends on 21, 22, 23, 24) The method of any of claims 21-24, wherein the carbon substrate is a graphite foam. ### Claim 26 (depends on 21, 22, 23, 24, 25) The method of any of claims 21-25, wherein the carbon substrate is a graphite foam formed by chemical vapor deposition of graphene on a nickel foam, and the nickel is removed by electrolytic etching. ### Claim 27 (depends on 21, 22, 23, 24, 25, 26) The method of any of claims 21-26, wherein the carbon substrate is a 3D printed graphite foam. ### Claim 28 (depends on 21, 22, 23, 24, 25, 26, 27) The method of any of claims 21-27, wherein the buffer layer is about 1 to about 10 nm thick. ### Claim 29 (depends on 21, 22, 23, 24, 25, 26, 27, 28) The method of any of claims 21-28, wherein the buffer layer is about 5 nm thick. ### Claim 30 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29) The method of any of claims 21-29, wherein the buffer layer comprises a metal oxide. ### Claim 31 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30) The method of any of claims 21-30, wherein the buffer layer comprises aluminum oxide, zinc oxide, silicon oxide, or combinations thereof. ### Claim 32 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31) The method of any of claims 21-31, wherein the buffer layer comprises aluminum oxide. ### Claim 33 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32) The method of any of claims 21-32, wherein the buffer layer comprises a layer of aluminum oxide from about 2 to about 10 nm thick. ### Claim 34 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33) The method of any of claims 21-33, wherein the buffer layer comprises a layer of aluminum oxide about 5 nm thick. ### Claim 35 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34) The method of any of claims 21-34, wherein the catalyst is an iron catalyst. ### Claim 36 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35) The method of any of claims 21-35, wherein the catalyst is formed from ferrocene. ### Claim 37 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36) The method of any of claims 21-36, wherein the catalyst is deposited as a layer. ### Claim 38 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37) The method of any of claims 21-37, wherein the catalyst is deposited as a layer from about 2 to about 20 nm thick. ### Claim 39 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38) The method of any of claims 21-38, wherein the catalyst is deposited as particles. ### Claim 40 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39) The method of any of claims 21-39, wherein the catalyst is deposited as particles from about 2 to about 20 nm in size. ### Claim 41 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40) The method of any of claims 21-40, wherein the catalyst is deposited using atomic layer deposition. ### Claim 42 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41) The method of any of claims 21-41, wherein the catalyst is deposited using chemical vapor deposition. ### Claim 43 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42) The method of any of claims 21-42, wherein the catalyst is deposited by a vapor phase metal source. ### Claim 44 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43) The method of any of claims 21-43, wherein the carbon nanotubes are from 1 about to about 500 micrometers in length. ### Claim 45 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44) The method of any of claims 21-44, wherein the carbon nanotubes are from about 250 to about 500 micrometers in length. ### Claim 46 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45) The method of any of claims 21-45, wherein the carbon nanotubes are from about 1 to about 50 nm in diameter. ### Claim 47 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46) The method of any of claims 21-46, wherein the carbon nanotubes are about 10 nm in diameter. ### Claim 48 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47) The method of any of claims 21-47, wherein the carbon nanotubes comprise single walled nanotubes, double walled nanotubes, multi walled nanotubes, or a combination thereof. ### Claim 49 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48) The method of any of claims 21-48, wherein the carbon substrate is plasma treated prior to atomic layer deposition. ### Claim 50 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49) The method of any of claims 21-49, wherein the carbon substrate is oxygen-plasma treated prior to atomic layer deposition. ### Claim 51 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50) The method of any of claims 21-50, wherein the carbon substrate is oxygen-plasma treated for from about 1 to about 5 minutes prior to atomic layer deposition. ### Claim 52 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51) The method of any of claims 21-51, wherein the working gas comprises a hydrocarbon gas. ### Claim 53 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52) The method of any of claims 21-52, wherein the working gas comprises ethylene, acetylene, methane, benzene, toluene or a combination thereof. ### Claim 54 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53) The method of any of claims 21-53, where in the working gas is flowed at a rate of about 1 to about 1000 sccm over the carbon substrate. ### Claim 55 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54) The method of any of claims 21-54, wherein the temperature remains elevated and the working gas is flowed for from about 1 to about 60 minutes. ### Claim 56 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55) The method of any of claims 21-55, wherein the elevated temperature is from about 400° C. to about 1100° C. ### Claim 57 A composition comprising: a conformal layer of carbon nanotubes on a porous substrate. ### Claim 58 (depends on 57) The composition of claim 57, wherein the porous substrate is a metal foam. ### Claim 59 (depends on 57, 58) The composition of any of the claims 57-58, wherein the porous substrate is a carbon foam. ### Claim 60 (depends on 57, 58, 59) The composition of any of the claims 57-59, wherein the porous substrate is a graphite foam. ### Claim 61 (depends on 57, 58, 59, 60) The composition of any of the claims 57-60, wherein the porous substrate is a 3D printed graphite foam. ### Claim 62 (depends on 57, 58, 59, 60, 61) The composition of any of the claims 57-61, wherein the carbon nanotubes are from about 1 to about 500 micrometers in length. ### Claim 63 (depends on 57, 58, 59, 60, 61, 62) The composition of any of the claims 57-62, wherein the carbon nanotubes are from about 250 to about 500 micrometers in length. ### Claim 64 (depends on 57, 58, 59, 60, 61, 62, 63) The composition of any of the claims 57-63, wherein the carbon nanotubes are from about 1 to about 50 nm in diameter. ### Claim 65 (depends on 57, 58, 59, 60, 61, 62, 63, 64) The composition of any of the claims 57-64, wherein the carbon nanotubes comprise single walled nanotubes, double walled nanotubes, multi walled nanotubes, or a combination thereof. ### Claim 66 A composition comprising: a layer of carbon nanotubes on a carbon substrate and a phase change material. ### Claim 67 A method for contacting a phase change material with a composition comprising a layer of carbon nanotubes on a carbon substrate, comprising plasma treating the layer of carbon nanotubes on a carbon substrate. ### Claim 68 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66) A method of use of the material from any of claims 21-66 as a thermal conductivity substrate for flexible graphene electronic devices. ### Claim 69 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66) A method of use of the material from any of claims 21-66 as an electrode in a battery. ### Claim 70 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66) A method of use of the material from any of claims 21-66 in a thermal storage device. ### Claim 71 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66) A method of use of the material from any of claims 21-66 in a heat exchange device. ### Claim 72 (depends on 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66) A method of use of the material from any of claims 21-66 with a phase change material in a thermal storage unit. ### Claim 73 A thermal storage unit comprising: a heat exchange path through which a heat exchange medium flows; and a thermal storage medium in thermal contact with the heat exchange path; wherein the thermal storage medium comprises a composite which comprises a porous thermally conductive matrix and a phase change material disposed within the porous thermally conductive matrix. ### Claim 74 (depends on 73) The unit of claim 73, wherein the heat exchange path comprises a tube having a central axis and a tube wall having an inner surface and an outer surface, wherein the tube wall is coaxially disposed about the central axis so as to define a lumen through which the heat exchange medium flows. ### Claim 75 (depends on 74) The unit of claim 74, wherein the thermal storage medium is in physical contact with the outer surface of the tube. ### Claim 76 (depends on 74, 75) The unit of claim 74 or 75, wherein the thermal storage medium surrounds the tube. ### Claim 77 (depends on 73, 74, 75, 76) The unit of any of claims 73-76, wherein the porous thermally conductive matrix comprises an isotropic thermally conductive matrix. ### Claim 78 (depends on 73, 74, 75, 76) The unit of any of claims 73-76, wherein the porous thermally conductive matrix comprises an anisotropic thermally conductive matrix. ### Claim 79 (depends on 78) The unit of claim 78, wherein the anisotropic thermally conductive matrix comprises a thermally conductive matrix configured to exhibit increased thermal conductivity along an axis orthogonal to heat exchange path relative to the thermal conductivity along an axis parallel to heat exchange path. ### Claim 80 (depends on 78, 79) The unit of claim 78 or 79, wherein the anisotropic thermally conductive matrix comprises a thermally conductive matrix configured to exhibit increased thermal conductivity along a plurality of axes radially extending from the heat exchange path relative to the thermal conductivity along an axis parallel to heat exchange path. ### Claim 81 (depends on 73, 74, 75, 76, 77, 78, 79, 80) The unit of any of claims 73-80, wherein the porous thermally conductive matrix comprises a graphite foam, a carbon foam, a 3D-printed graphite matrix, a metal foam, or combinations thereof. ### Claim 82 (depends on 81) The unit of claim 81, wherein the graphite foam, the carbon foam, the 3D-printed graphite matrix, the metal foam, or combinations thereof further comprises a conformal layer of carbon nanotubes disposed on the graphite foam, the carbon foam, the 3D-printed graphite matrix, the metal foam, or combinations thereof. ### Claim 83 (depends on 73, 74, 75, 76, 77, 78, 79, 80, 81, 82) The unit of any of claims 73-82, wherein the phase change material has a melting temperature of from about 50° C. to about 225° C. ### Claim 84 (depends on 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83) The unit of any of claims 73-83, wherein the phase change material has a melting enthalpy of from about 200 MJ/m3 to about 400 MJ/m3. ### Claim 85 (depends on 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84) The unit of any of claims 73-84, wherein the phase change material comprises a sugar alcohol or a blend of sugar alcohols. ### Claim 86 (depends on 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85) The unit of any of claims 73-85, wherein the phase change material comprises a blend of mannitol and galactitol. ### Claim 87 (depends on 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86) The unit of any of claims 73-86, further comprising a plurality of heat exchange paths through which a heat exchange medium flows. ### Claim 88 (depends on 87) The unit of claim 87, wherein each heat exchange path comprises a tube having a central axis and a tube wall having an inner surface and an outer surface, wherein the tube wall is coaxially disposed about the central axis so as to define a lumen through which the heat exchange medium flows, and wherein the central axes of each of the tubes are substantially parallel to each other. ### Claim 89 (depends on 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88) The unit of any of claims 73-88, further comprising a housing enclosing the heat exchange path and the thermal storage medium. ### Claim 90 (depends on 89) The unit of claim 89, further comprising an inlet port and an outlet port for transferring a heat exchange medium to the heat exchange path.