GB2179135A - Heat storage - Google Patents

Heat storage Download PDF

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Publication number
GB2179135A
GB2179135A GB08520407A GB8520407A GB2179135A GB 2179135 A GB2179135 A GB 2179135A GB 08520407 A GB08520407 A GB 08520407A GB 8520407 A GB8520407 A GB 8520407A GB 2179135 A GB2179135 A GB 2179135A
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GB
United Kingdom
Prior art keywords
heat
heat storage
medium
water
fusion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB08520407A
Other versions
GB8520407D0 (en
Inventor
Michael Allen Gilbey
Paul Halewood
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STEETLEY CHEMICALS Ltd
Original Assignee
STEETLEY CHEMICALS Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by STEETLEY CHEMICALS Ltd filed Critical STEETLEY CHEMICALS Ltd
Priority to GB08520407A priority Critical patent/GB2179135A/en
Publication of GB8520407D0 publication Critical patent/GB8520407D0/en
Publication of GB2179135A publication Critical patent/GB2179135A/en
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
    • C09K5/02—Materials undergoing a change of physical state when used
    • C09K5/06—Materials undergoing a change of physical state when used the change of state being from liquid to solid or vice versa
    • C09K5/063—Materials absorbing or liberating heat during crystallisation; Heat storage materials

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Thermal Sciences (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Central Heating Systems (AREA)
  • Thermotherapy And Cooling Therapy Devices (AREA)

Abstract

A heat storage medium consisting essentially of from 70% to 98% of magnesium nitrate hexahydrate and from 30% to 2% of calcium nitrate tetrahydrate is provided. The heat storage medium may be contained within a sealed container to form a heat storage product which may be used to store heat produced by the use of off-peak electricity.

Description

SPECIFICATION Heat storage The present invention relates to heat storage.
It is well known that on fusion materials absorb heat which is released again on solidification. This phenomenon is utilised as a means of storing heat.
In the case where heat is being provided by off-peak electricity for use in central heating it is convenient to use water as a heating medium. One or more electric immersion heaters placed in the water heat the water. Sealed containers into which the fusible material has been filled are placed in the water and the fusible material is heated by the water.
In order that the maximum possible amount of heat be stored by the fusible material, all the fusible material present should undergo fusion during the off-peak period. It is also important that the temperature at which fusion occurs should be as high as possible in relation to the temperature of water, the heating medium. The composition of the present invention provides such a material.
Accordingly the present invention provides a heat storage medium consisting essentially of 70-98% magnesium nitrate hexahydrate and 30-2% calcium nitrate tetrahydrate.
The water in this application is heated by means of the off-peak electricity to the maximum practicable temperature, usually in the range 92-98"C. It has been found that in order to ensure fusion of all the fusible material in the time available the temperature at which fusion occurs in a useful central heating application should be in the range 70-90 C preferably 75-88"C.
There may be a relatively small deficiency or excess in the proportion of water represented by the stated medium. There may also be present functional or adventitious materials provided that they have no significant effect on the crystallisation of the medium.
The present invention is also for a heat storage product which comprises a heat storage medium as described above contained within a suitable container e.g. a sealed metai or plastics package. Desirably the container will be of narrow section fln relation to its length to facilitate the transfer of heat.
Moreover the present invention is for a means for storing off-peak electricity comprising a heat transfer medium such as water contained within the vessel and, immersed in the heat transfer medium, one or more immersion heaters and one or more heat storage products as defined above.
The number and size of the heat storage products will naturally depend on the amount of heat it is wished to store.
During the heat storage stage in the operation of the above means, the water, for example, is heated by the immersion heater(s) and this heat is transferred to the heat storage medium within the container(s). When the medium reaches the temperature at which fusion of the medium takes place, heat is absorbed by the medium at substantially constant temperature until the medium has fused.
During the heat extraction stage, water in the vessel is circulated around a central heating system and, in so doing, loses heat to the system. The cooled water on returning to the vessel extracts heat from the medium which, in the process, gradually crystallises without any significant reduction in temperature.
An example of a composition which has been found useful consists of 88% magnesium nitrate hexahydrate and 12% calcium nitrate tetrahydrate and has a fusion temperature of 85"C.
It is to be understood that the present invention includes, in one of its aspects, the use of the above described heat storage medium consisting essentially of 70-98% magnesium nitrate hexahydrate and 30-2% calcium nitrate tetrahydrate for storing and providing heat. Further the most preferred composition for storing heat consists of 88% magnesium nitrate hexahydrate and 12% calcium nitrate tetrahydrate, although the former compound is particularly useful over the range 84-98% and the latter compound over the range 16-8%.
1. A heat storage medium consisting essentially of from 70% to 98% of magnesium nitrate hexahydrate and from 30% to 2% of calcium nitrate tetrahydrate.
2. A heat storage medium as claimed in claim 1 wherein the percentage of magnesium nitrate hexahydrate is from 84 to 92 and the percentage of calcium nitrate tetrahydrate is from 16 to 8.
3. A heat storage medium as claimed in claim 2 consisting essentially of 88% magnesium nitrate hexahydrate and 12% calcium nitrate tetrahydrate.
4. A heat storage medium as claimed in any one of the preceding claims wherein the fusion of the medium occurs in the temperature range of from 70 to 90".
5. A heat storage medium as claimed in claim 4 wherein the fusion of the medium occurs in the temperature range of from 75 to 88"C.
6. A heat storage medium as claimed in claim 6 wherein the fusion of the medium occurs at a temperature of 85"C.
7. A heat storage product comprising a heat storage medium as claimed in any one of the preceding claims contained within a suitable sealed container.
8. A heat storage product as claimed in claim 7 wherein the sealed container is of narrow section in relation to its length.
9. A heat storage means for storing heat produced by the use of off-peak electricity
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Heat storage The present invention relates to heat storage. It is well known that on fusion materials absorb heat which is released again on solidification. This phenomenon is utilised as a means of storing heat. In the case where heat is being provided by off-peak electricity for use in central heating it is convenient to use water as a heating medium. One or more electric immersion heaters placed in the water heat the water. Sealed containers into which the fusible material has been filled are placed in the water and the fusible material is heated by the water. In order that the maximum possible amount of heat be stored by the fusible material, all the fusible material present should undergo fusion during the off-peak period. It is also important that the temperature at which fusion occurs should be as high as possible in relation to the temperature of water, the heating medium. The composition of the present invention provides such a material. Accordingly the present invention provides a heat storage medium consisting essentially of 70-98% magnesium nitrate hexahydrate and 30-2% calcium nitrate tetrahydrate. The water in this application is heated by means of the off-peak electricity to the maximum practicable temperature, usually in the range 92-98"C. It has been found that in order to ensure fusion of all the fusible material in the time available the temperature at which fusion occurs in a useful central heating application should be in the range 70-90 C preferably 75-88"C. There may be a relatively small deficiency or excess in the proportion of water represented by the stated medium. There may also be present functional or adventitious materials provided that they have no significant effect on the crystallisation of the medium. The present invention is also for a heat storage product which comprises a heat storage medium as described above contained within a suitable container e.g. a sealed metai or plastics package. Desirably the container will be of narrow section fln relation to its length to facilitate the transfer of heat. Moreover the present invention is for a means for storing off-peak electricity comprising a heat transfer medium such as water contained within the vessel and, immersed in the heat transfer medium, one or more immersion heaters and one or more heat storage products as defined above. The number and size of the heat storage products will naturally depend on the amount of heat it is wished to store. During the heat storage stage in the operation of the above means, the water, for example, is heated by the immersion heater(s) and this heat is transferred to the heat storage medium within the container(s). When the medium reaches the temperature at which fusion of the medium takes place, heat is absorbed by the medium at substantially constant temperature until the medium has fused. During the heat extraction stage, water in the vessel is circulated around a central heating system and, in so doing, loses heat to the system. The cooled water on returning to the vessel extracts heat from the medium which, in the process, gradually crystallises without any significant reduction in temperature. An example of a composition which has been found useful consists of 88% magnesium nitrate hexahydrate and 12% calcium nitrate tetrahydrate and has a fusion temperature of 85"C. It is to be understood that the present invention includes, in one of its aspects, the use of the above described heat storage medium consisting essentially of 70-98% magnesium nitrate hexahydrate and 30-2% calcium nitrate tetrahydrate for storing and providing heat. Further the most preferred composition for storing heat consists of 88% magnesium nitrate hexahydrate and 12% calcium nitrate tetrahydrate, although the former compound is particularly useful over the range 84-98% and the latter compound over the range 16-8%. CLAIMS
1. A heat storage medium consisting essentially of from 70% to 98% of magnesium nitrate hexahydrate and from 30% to 2% of calcium nitrate tetrahydrate.
2. A heat storage medium as claimed in claim 1 wherein the percentage of magnesium nitrate hexahydrate is from 84 to 92 and the percentage of calcium nitrate tetrahydrate is from 16 to 8.
3. A heat storage medium as claimed in claim 2 consisting essentially of 88% magnesium nitrate hexahydrate and 12% calcium nitrate tetrahydrate.
4. A heat storage medium as claimed in any one of the preceding claims wherein the fusion of the medium occurs in the temperature range of from 70 to 90".
5. A heat storage medium as claimed in claim 4 wherein the fusion of the medium occurs in the temperature range of from 75 to 88"C.
6. A heat storage medium as claimed in claim 6 wherein the fusion of the medium occurs at a temperature of 85"C.
7. A heat storage product comprising a heat storage medium as claimed in any one of the preceding claims contained within a suitable sealed container.
8. A heat storage product as claimed in claim 7 wherein the sealed container is of narrow section in relation to its length.
9. A heat storage means for storing heat produced by the use of off-peak electricity comprising a heat transfer medium, such as water, contained within a vessel and, immersed in that heat transfer medium one or more immersion heaters to produce said heat and one or more heat storage products as claimed in claim 7 or claim 8.
10. The use of a composition consisting essentially of from 70 to 98% magnesium nitrate hexahydrate and from 30% to 2% of calcium nitrate tetrahydrate as a heat storage medium.
GB08520407A 1985-08-14 1985-08-14 Heat storage Withdrawn GB2179135A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08520407A GB2179135A (en) 1985-08-14 1985-08-14 Heat storage

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08520407A GB2179135A (en) 1985-08-14 1985-08-14 Heat storage

Publications (2)

Publication Number Publication Date
GB8520407D0 GB8520407D0 (en) 1985-09-18
GB2179135A true GB2179135A (en) 1987-02-25

Family

ID=10583786

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08520407A Withdrawn GB2179135A (en) 1985-08-14 1985-08-14 Heat storage

Country Status (1)

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GB (1) GB2179135A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993012193A1 (en) * 1991-12-14 1993-06-24 Merck Patent Gmbh Mixtures of salts for storing thermal energy as phase transition heat
CN109609098A (en) * 2018-12-12 2019-04-12 上海交通大学 A kind of composite phase-change heat-storage material and its preparation

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5591374A (en) * 1991-01-10 1997-01-07 Merck Patent Gesellschaft Mit Beschrankter Haftung Salt mixtures for storing thermal energy in the form of heat of phase transformation
US5728316A (en) * 1991-01-10 1998-03-17 Merck Patent Gesellschaft Mit Beschrankter Haftung Salt mixtures for storing thermal energy in the form of that of phase transformation
WO1993012193A1 (en) * 1991-12-14 1993-06-24 Merck Patent Gmbh Mixtures of salts for storing thermal energy as phase transition heat
CN109609098A (en) * 2018-12-12 2019-04-12 上海交通大学 A kind of composite phase-change heat-storage material and its preparation

Also Published As

Publication number Publication date
GB8520407D0 (en) 1985-09-18

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