US4637888A
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Reversible phase change composition for storing energy
Assignee: Dow Chemical Co
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Filing: 1985-06-11
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Granted: 1987-01-20
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Expires: 2005-06-11
Abstract
Abstract A reversible liquid/solid phase change composition for the storage of energy comprising a mixture of hydrated calcium bromide/calcium chloride and a modifier selected from KBr, KCl, or mixtures thereof, for modifying the semicongruent melting of the mixture to reduce the formation of crystalline CaBr 2 and CaCl 2 hydrate phases other than the hexahydrate phase. The composition is useful over a temperature range of from about 5° to about 50° C. and can be employed for the storage of coolness or heat, or as a buffer or heat sink to modulate diurnal swings in ambient temperature.
Inventors
- 👤 George A. Lane
- 👤 Harold E. Rossow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:30
CPC Classifications
C; C09; C09K; C09K5/00; C09K5/02; C09K5/06; C09K5/063
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
128 words
A reversible liquid/solid phase change composition having a melting temperature of from about 5° to about 50° C., said composition comprising a hydrated mixture of from about 20 to about 67 weight percent CaBr 2 , from greater than zero to about 38 weight percent CaCl 2 , from about 28 to about 50 weight percent water, and a modifier selected from the group consisting of KBr, and mixtures of KBr and KCl, said modifier being present in an amount greater than zero to less than about 10 weight percent and sufficient to modify the semicongruent melting behavior of the CaBr 2 /CaCl 2 mixture to reduce, during freezing of the composition, the formation of crystalline CaBr 2 and CaCl 2 hydrate phases other than the hexahydrate phase.
Claim 2
Dependent Claim
128 words
A reversible liquid/solid phase change composition having a melting temperature of from about 5° to about 50° C., said composition comprising a hydrated mixture of from about 20 to about 67 weight percent CaBr 2 , from greater than zero to about 38 weight percent CaCl 2 , from about 28 to about 50 weight percent water, and a modifier selected from the group consisting of KBr, and mixtures of KBr and KCl, said modifier being present in an amount greater than zero to less than about 10 weight percent and sufficient to modify the semicongruent melting behavior of the CaBr 2 /CaCl 2 mixture to reduce, during freezing of the composition, the formation of crystalline CaBr 2 and CaCl 2 hydrate phases other than the hexahydrate phase.
Claim 3
Dependent Claim
41 words
The composition of claim 1, wherein said mixture comprises from about 28 to about 43 weight percent CaBr 2 , from about 14 to about 31 weight percent CaCl 2 , and from about 34 to about 48 weight percent water.
Claim 4
Dependent Claim
59 words
The composition of claim 2, wherein said mixture comprises from about 30 to about 41 weight percent CaBr 2 , from about 18 to about 26 weight percent CaCl 2 , from about 2 to about 5 weight percent of the modifier, with the remainder being water in an amount of up to 100 weight percent of the composition.
Claim 5
Dependent Claim
59 words
The composition of claim 2, wherein said admixture comprises from about 32 to about 37 weight percent CaBr 2 ; from about 20 to about 24 weight percent CaCl 2 , from about 3 to about 4 weight percent of the modifier, with the remainder being water in an amount of up to 100 weight percent of the composition.
Claim 6
Dependent Claim
41 words
The composition of claim 1, wherein said mixture comprises from about 38 to about 55 weight percent CaBr 2 , from about 10 to about 25 weight percent CaCl 2 , and from about 29 to about 43 weight percent water.
Claim 7
Dependent Claim
57 words
The composition of claim 5, wherein said mixture comprises from about 42 to about 55 weight percent CaBr 2 , from about 10 to about 17 weight percent CaCl 2 , and from about 36 to about 40 weight percent water, said modifier being present in an amount of from about 2 to about 5 weight percent.
Claim 8
Dependent Claim
58 words
The composition of claim 5, wherein said mixture comprises from about 46 to about 52 weight percent CaBr 2 , from greater than 10 to about 15 weight percent CaCl 2 , and from about 37 to about 39 weight percent water, said modifier being present in an amount of from about 3 to about 4 weight percent.
Claim 9
Dependent Claim
41 words
The composition of claim 1, wherein said mixture comprises from about 20 to about 28 weight percent CaBr 2 , from about 21 to about 38 weight percent CaCl 2 , and from about 33 to about 50 weight percent water.
Claim 10
Dependent Claim
57 words
The composition of claim 8, wherein said mixture comprises from about 20 to about 28 weight percent CaBr 2 , from about 25 to about 36 weight percent CaCl 2 , and from about 40 to about 48 weight percent water, said modifier being present in an amount of from about 2 to about 5 weight percent.
Claim 11
Dependent Claim
57 words
The composition of claim 8, wherein said mixture comprises from about 20 to about 28 weight percent CaBr 2 , from about 28 to about 35 weight percent CaCl 2 , and from about 43 to about 46 weight percent water, said modifier being present in an amount of from about 3 to about 4 weight percent.
Claim 12
Dependent Claim
44 words
The composition of claim 1, wherein said mixture comprises from about 47 to about 67 weight percent CaBr 2 , from greater than zero to less than about 10 weight percent CaCl 2 , and from about 29 to about 43 weight percent water.
Claim 13
Dependent Claim
58 words
The composition of claim 11, wherein said mixture comprises from about 50 to about 66 weight percent CaBr 2 , from greater than zero to about 10 weight percent CaCl 2 , and from about 31 to about 40 weight percent water, said modifier being present in an amount of from about 2 to about 5 weight percent.
Claim 14
Dependent Claim
58 words
The composition of claim 11, wherein said mixture comprises from about 52 to about 65 weight percent CaBr 2 , from greater than zero to about 10 weight percent CaCl 2 , and from about 33 to about 36 weight percent water, said modifier being present in an amount of from about 3 to about 4 weight percent.
Claim 15
Dependent Claim
37 words
The composition of claim 1, including one or more nucleating agents in the composition in an amount sufficient to reduce supercooling of the composition to less than 3° C. during retrieval of the stored energy by crystallization.
Claim 16
Dependent Claim
24 words
The composition of claim 14, wherein the nucleating agent is added in an amount of from greater than zero to about 5.0 weight percent.
Claim 17
Dependent Claim
43 words
The composition of claim 14, wherein the nucleating agent is selected from the group consisting of SrCl 2 , Ba(OH) 2 , SrBr 2 , Sr(OH) 2 , SrI 2 , BaI 2 , BaO, BaCO 3 , SrCO 3 and mixtures thereof.
Claim 18
Dependent Claim
138 words
A reversible liquid/solid phase change composition having a melting temperature of from about 5° C. to about 50° C., said composition comprising a hydrated mixture of from about 20 to about 67 weight percent CaBr 2 , from greater than zero to about 38 weight percent CaCl 2 , from about 28 weight percent water up to about 6.0 moles of water per mole of calcium salt and from greater than 6.14 moles of water per mole of calcium salt up to about 50 weight percent water and from greater than zero to less than about 10 weight pecent KCl but sufficient to modify the semicongruent melting behavior of the CaBr 2 /CaCl 2 mixture to reduce, during freezing of the composition, the formation of crystalline CaBr 2 and CaCl 2 hydrate phases other than the hexahydrate phase.
Claim 19
Dependent Claim
138 words
A reversible liquid/solid phase change composition having a melting temperature of from about 5° C. to about 50° C., said composition comprising a hydrated mixture of from about 20 to about 67 weight percent CaBr 2 , from greater than zero to about 38 weight percent CaCl 2 , from about 28 weight percent water up to about 6.0 moles of water per mole of calcium salt and from greater than 6.14 moles of water per mole of calcium salt up to about 50 weight percent water and from greater than zero to less than about 10 weight pecent KCl but sufficient to modify the semicongruent melting behavior of the CaBr 2 /CaCl 2 mixture to reduce, during freezing of the composition, the formation of crystalline CaBr 2 and CaCl 2 hydrate phases other than the hexahydrate phase.
Claim 20
Dependent Claim
31 words
The composition of claim 17, wherein said mixture comprises from about 28 to about 43 weight percent CaBr 2 , from about 14 to about 31 weight percent CaCl 2 .
Claim 21
Dependent Claim
43 words
The composition of claim 18, wherein said mixture comprises from about 30 to about 41 weight percent CaBr 2 , from about 18 to about 26 weight percent CaCl 2 , and from about 2 to about 5 weight percent of the modifier.
Claim 22
Dependent Claim
43 words
The composition of claim 18 wherein said admixture comprises from about 32 to about 37 weight percent CaBr 2 , from about 20 to about 24 weight percent CaCl 2 , and from about 3 to about 4 weight percent of the modifier.
Claim 23
Dependent Claim
31 words
The composition of claim 17, wherein said mixture comprises from about 38 to about 55 weight percent CaBr 2 , from about 10 to about 25 weight percent CaCl 2 .
Claim 24
Dependent Claim
48 words
The composition of claim 21, wherein said mixture comprises from about 42 to about 55 weight percent CaBr 2 , from about 10 to about 17 weight percent CaCl 2 , and said modifier being present in an amount of from about 2 to about 5 weight percent.
Claim 25
Dependent Claim
48 words
The composition of claim 21, wherein said mixture comprises from about 46 to about 52 weight percent CaBr 2 , from about 10 to about 15 weight percent CaCl 2 , and said modifier being present in an amount of from about 3 to about 4 weight percent.
Claim 26
Dependent Claim
32 words
The composition of claim 17, wherein said mixture comprises from about 20 to about 28 weight percent CaBr 2 , and from about 21 to about 38 weight percent CaCl 2 .
Claim 27
Dependent Claim
48 words
The composition of claim 24, wherein said mixture comprises from about 20 to about 28 weight percent CaBr 2 , from about 25 to about 36 weight percent CaCl 2 , and said modifier being present in an amount of from about 2 to about 5 weight percent.
Claim 28
Dependent Claim
48 words
The composition of claim 24, wherein said mixture comprises from about 20 to about 28 weight percent CaBr 2 , from about 28 to about 35 weight percent CaCl 2 , and said modifier being present in an amount of from about 3 to about 4 weight percent.
Claim 29
Dependent Claim
33 words
The composition of claim 17, wherein said mixture comprises from about 47 to about 67 weight percent CaBr 2 , and from greater than zero to about 10 weight percent CaCl 2 .
Claim 30
Dependent Claim
49 words
The composition of claim 27, wherein said mixture comprises from about 50 to about 66 weight percent CaBr 2 , from greater than zero to about 10 weight percent CaCl 2 , and said modifier being present in an amount of from about 2 to about 5 weight percent.
Claim 31
Dependent Claim
49 words
The composition of claim 27, wherein said mixture comprises from about 52 to about 65 weight percent CaBr 2 , from greater than zero to about 10 weight percent CaCl 2 , and said modifier being present in an amount of from about 3 to about 4 weight percent.
Claim 32
Dependent Claim
34 words
The composition of claim 17, including one or more nucleating agents in an amount sufficient to reduce supercooling of the composition to less than 3° C. during retrieval of the stored energy by crystallization.
Claim 33
Dependent Claim
24 words
The composition of claim 30, wherein the nucleating agent is present in an amount of from greater than zero to about 5.0 weight percent.
Claim 34
Dependent Claim
44 words
The composition of claim 30, wherein the nucleating agent is selected from the group consisting of SrCl 2 , Ba(OH) 2 , SrBr 2 , Sr(OH) 2 , SrI 2 , BaI 2 , BaO, BaCO 3 , SrCO 3 , and mixtures thereof.
Claim 35
Dependent Claim
43 words
An energy storage device comprising an encapsulating means containing the reversible liquid/solid phase change composition of claim 1 or 17, wherein said phase change composition is hermetically sealed in said encapsulating means to prevent the evaporation of water from the phase change composition.
Claim 36
Independent Claim
160 words
A method of storing energy, comprising the steps of preparing a reversible liquid/solid phase change composition which melts at a temperature of from about 5° to about 50° C., by admixing from about 20 to about 67 weight percent CaBr 2 , from greater than zero to about 38 weight percent CaCl 2 , from about 28 to about 50 weight percent water, and a modifier in an amount greater than zero but less than about 10 weight percent and in an amount sufficient to modify the semicongruent melting behavior of the CaBr/CaCl 2 mixture to reduce, during freezing of the composition, the formation of crystalline hydrate phases other than the hexahydrate phase, said modifier being selected from the group consisting of KBr, and mixtures of KBr and KCl, introducing the composition into an encapsulating means for use as an energy storage device, and hermetically sealing the encapsulating means to prevent the escape of water vapors from the encapsulating means.
Claim 37
Independent Claim
160 words
A method of storing energy, comprising the steps of preparing a reversible liquid/solid phase change composition which melts at a temperature of from about 5° to about 50° C., by admixing from about 20 to about 67 weight percent CaBr 2 , from greater than zero to about 38 weight percent CaCl 2 , from about 28 to about 50 weight percent water, and a modifier in an amount greater than zero but less than about 10 weight percent and in an amount sufficient to modify the semicongruent melting behavior of the CaBr/CaCl 2 mixture to reduce, during freezing of the composition, the formation of crystalline hydrate phases other than the hexahydrate phase, said modifier being selected from the group consisting of KBr, and mixtures of KBr and KCl, introducing the composition into an encapsulating means for use as an energy storage device, and hermetically sealing the encapsulating means to prevent the escape of water vapors from the encapsulating means.
Claim 38
Dependent Claim
90 words
The method of claim 34, including the step of adding a nucleating agent in an amount sufficient to reduce supercooling of the composition to less than 3° C. during retrieval of the stored energy by crystallization, said nucleating agent being selected from the group consisting of SrCl 2 , Ba(OH) 2 , BaO, SrCo 3 , SrBr 2 , Sr(OH) 2 , SrI 2 , BaI, BaCO 3 , and mixtures thereof, said nucleating agent being added in an amount of from greater than zero to about 5.0 weight percent.
Claim 39
Independent Claim
177 words
A method of storing energy, comprising the steps of preparing a reversible liquid/solid phase change composition which melts at a temperature of from about 5° to about 50° C., by admixing from about 20 to about 67 weight percent CaBr 2 , from greater than zero to about 38 weight percent CaCl 2 , and from about 28 weight percent water up to about 6.0 moles of water per mole of calcium salt and an amount greater than 6.14 moles of water per mole of calcium salt up to about 50 weight percent water, and KCl as a modifier in an amount greater than zero but less than about 10 weight percent but in an amount sufficient to modify the semicongruent melting behavior of the CaBr/CaCl 2 mixture to reduce, during freezing of the composition, the formation of crystalline hydrate phases other than the hexahydrate phase, introducing the composition into an encapsulating means for use as an energy storage device, and hermetically sealing the encapsulating means to prevent the escape of water vapors from the encapsulating means.
Claim 40
Independent Claim
177 words
A method of storing energy, comprising the steps of preparing a reversible liquid/solid phase change composition which melts at a temperature of from about 5° to about 50° C., by admixing from about 20 to about 67 weight percent CaBr 2 , from greater than zero to about 38 weight percent CaCl 2 , and from about 28 weight percent water up to about 6.0 moles of water per mole of calcium salt and an amount greater than 6.14 moles of water per mole of calcium salt up to about 50 weight percent water, and KCl as a modifier in an amount greater than zero but less than about 10 weight percent but in an amount sufficient to modify the semicongruent melting behavior of the CaBr/CaCl 2 mixture to reduce, during freezing of the composition, the formation of crystalline hydrate phases other than the hexahydrate phase, introducing the composition into an encapsulating means for use as an energy storage device, and hermetically sealing the encapsulating means to prevent the escape of water vapors from the encapsulating means.
Claim 41
Dependent Claim
90 words
The method of claim 36, including the step of adding a nucleating agent in an amount sufficient to reduce supercooling of the composition to less than 3° C. during retrieval of the stored energy by crystallization, said nucleating agent being selected from the group consisting of SrCl 2 , Ba(OH) 2 , BaO, SrBr 2 , Sr(OH) 2 , SrCO 3 , SrI 2 , BaI, BaCO 3 , and mixtures thereof, said nucleating agent being added in an amount of from greater than zero to about 5.0 weight percent.
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