IL256626A - Compositions of phase change materials for energy storage - Google Patents
Compositions of phase change materials for energy storageInfo
- Publication number
- IL256626A IL256626A IL256626A IL25662617A IL256626A IL 256626 A IL256626 A IL 256626A IL 256626 A IL256626 A IL 256626A IL 25662617 A IL25662617 A IL 25662617A IL 256626 A IL256626 A IL 256626A
- Authority
- IL
- Israel
- Prior art keywords
- weight
- content
- k2so4
- caso4
- na2so4
- Prior art date
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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
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- Thermal Sciences (AREA)
- Inorganic Chemistry (AREA)
- Soil Conditioners And Soil-Stabilizing Materials (AREA)
Description
1
13/09/2018 256626/3
PCM Mixtures With Two Melting Points
For Cooling And Heating
Field of The Invention
The present invention relates to energy storage, in particular to compositions of
Phase Change Materials (PCMs).
Background of the Invention
A PCM is a substance with a high heat of fusion thus being capable of storing and
releasing large amounts of energy. Heat is absorbed or released when the material changes
from solid to liquid and vice versa.
Electricity rates in many countries vary during the day in such a way that during
hours of high consumption of electricity, the tariff is high while during hours low
consumption the tariff is low, (e.g., at night).
Three technological concepts are in common use today to reduce costs of electricity
demands for cooling purposes. These methods involve cooling of reservoirs of water, ice,
or salts solutions during low tariff hours while during high tariff hours those reservoirs
function as heat sink. The disadvantage of using water reservoirs is due to the need for
large volumes of water that require considerable space. The use of ice is ineffective (about
% of energy loss), and requires undesirable use of cooling with ethylene glycol. Using
solutions of eutectic salts as described in a US Patent 5,650,090 is accompanied with
problematic use of hazardous substances such as paraffins and ammonia. Ammonia is used
to prevent irreversible solidification of eutectic solutions as result of a formation of
hydrates. However there are suggestions attempting to obviate the hazardous use of 2
13/09/2018 256626/3
ammonia. JPH02248491 discloses composition which comprises a crosslinked polyacrylic
acid salt. CN104232024 discloses an energy-storage material which comprises the
following raw materials in percentage by weight of: 80%-96% of CaC12.mH2O, 1%-5% of
potassium salt, 1%-15% of heat conducting material, and 2%-3% of SrCl2.6H2O with the
particle size of not less than 0.9cm. CN10366638 discloses a composition that contains in
addition to an energy storage main body material, also thickening agent, nucleating agent,
and reinforcing material. The thickening agent comprises one or more of an inorganic
thickening agent, fibers, polyacrylates, polyurethanes and a natural polymer thickening
agent. The reinforcing material comprises one or more of metal and metal oxide powder,
carbon materials, nanoparticles and foam materials. Nucleating agent content is up to 8%
by weight.
However producing and using compositions as suggested above may be found
complicate and/or expensive. Therefore, there exists a need to find compositions enabling
to overcome the above disadvantages while efficient use and relative simplicity in their
production.3
13/09/2018 256626/3
Brief description of the Drawing
FIG. 1 is a Differential Scanning Calorimetry (DSC) thermogram of the PCM.
Summary of the Invention
The inventor of the present invention has surprisingly found a composition which
is efficient for use in cooling systems while being relatively simple for production and
based on available and inexpensive materials.
According to some aspects of the present invention there is provided a PCM
composition that includes a mixture of water and three sulfate salts, of Ca, K, and Na which
according to some embodiments of the above aspect the PCM composition may include 8
% CaSO4, 5-7% K2SO4, and 20-35% Na2SO4 by weight. According to particular
embodiment the PCM composition includes 14.2% CaSO4, 6.7% K2SO4, and 24% Na2SO4
by weight. According to another embodiment of the above aspect, the PCM composition
includes 8.3% CaSO4, 5.8% K2SO4, and 29% Na2SO4 by weight. According to some
embodiments of the above aspect, the PCM composition includes only water and three
sulfate salts: CaSO4, K2SO4, and Na2SO4. According to some embodiments of the above
aspect the melting point of the PCM is 4 to 8 0C or around 6 0C. According to some
embodiments the PCM composition may include 9% CaSO4, 6.4% K2SO4, and 32%
Na2SO4 by weight with a melting point of 8 0C.
A PCM composition according to some aspect of the present invention is obtainable
by mixing CaSO4, K2SO4, and Na2SO4, adding water (preferably filtered), and mixing until
obtaining a thickening uniform blend characterized with an increasing viscosity over time
and with a brittle however flowing texture.4
13/09/2018 256626/3
An advantageous feature of the compositions disclosed herein is that they typically
have two melting points- high and low. This allows for simultaneous use in the same
composition, for both heating and cooling. According to some embodiments of the
invention, a first lower melting point is utilized for cooling while a second higher melting
temperature is utilized to store heat for heating. Typically the second melting point is above
degrees Celsius.5
13/09/2018 256626/3
Detailed Description
Thermal energy storage (TES), also commonly referred to as heat and cold storage,
provides for the storage of heat or cold. To be able to use the heat or cold after some time,
their storage needs to be reversible. Thermal energy storage can be implemented by storage
of Sensible Heat or Latent Heat. The most common way of thermal energy storage is as
sensible heat. Heat transferred to the storage medium leads to a temperature increase of the
storage medium. The phase change solid-liquid by melting and solidification can store
large amounts of heat or cold. Melting is characterized by a small volume change, usually
less than 10%. Upon melting, while heat is transferred to the storage material, the material
still keeps its temperature constant at the melting temperature, also called phase change
temperature. If the melting is completed, further transfer of heat results again in sensible
heat storage. The heat supplied upon melting is called latent heat, and the process latent
heat storage.
Organic PCM are naturally existing petroleum products that have their unique
phase-change temperature. They can be toxic, flammable and expensive. However they are
characterized by infinite life cycles.
Existing inorganic PCM are engineered hydrated salt solution made from natural
salts with water. The chemical composition of salts is varied in the mixture to achieve
required phase-change temperature. Special nucleating agents are added to the mixture to
minimize phase-change salt separation and to minimize super cooling, that are otherwise
characteristic of hydrated salt PCM. Salt Hydrates are characteristic of being non-toxic,
nonflammable and economical.
Some of the advantages of PCM usage are:6
13/09/2018 256626/3
- Stored thermal energy is portable and rechargeable.
- Stored thermal energy as latent heat which allows higher thermal energy storage
capacity per unit of weight at constant temperature.
- Thermal energy storage at the temperature of process application.
- Separation between accumulating energy and its use allows benefiting from the
ability to accumulate energy when the costs are low.
- Store thermal energy during off demand hours and use during peak demand to save
on energy cost and help stabilize grid load.
- Allow sizing HVAC equipment for average load rather than peak load.
Three major PCM that are widespread in use today for energy storage for cooling
applications are utilizing reservoirs of water, ice, or salts solutions. The disadvantage of
using water reservoirs is due to the need for large volumes of water that require
considerable space. The use of ice is ineffective (about 30% of energy loss), and requires
undesirable use of ethylene glycol. Using solutions of eutectic salts as described in a US
Patent 5,650,090 is accompanied with problematic use of hazardous substances such as
paraffins and ammonia. Ammonia is used to prevent irreversible solidification of eutectic
solutions as result of a formation of hydrates, however there are suggestions attempting to
obviate the hazardous use of ammonia. Unfortunately until now, the production and the
use of the existing suggested compositions were found to be relatively complicated and
costly. Therefore, there exists a need to find compositions which enabling relative
simplicity in their production and an efficient use.
The inventor of the present invention has surprisingly found a composition which
is efficient for use in cooling systems while being relatively simple for production.
According to some aspects of the present invention there is provided a PCM
composition that includes mixtures of water and three sulfate salts of Ca, K, and Na.7
13/09/2018 256626/3
According to some embodiments of the above aspect the PCM composition includes 8
% CaSO4, 5-7% K2SO4, and 20-30% Na2SO4 by weight. According to particular
embodiment the PCM composition includes 14.2% CaSO4, 6.7% K2SO4, and 24% Na2SO4
by weight. According to another embodiment of the above aspect, the PCM composition
includes 8.3% CaSO4, 5.8% K2SO4, and 29% Na2SO4 by weight. According to some
embodiments of the above aspect, the PCM composition includes only water and three
sulfate salts: CaSO4, K2SO4, and Na2SO4. According to some embodiments of the above
aspect the melting point of the PCM is 4 to 8 0C or around 6 0C. According to some
embodiments the PCM composition may be 9% CaSO4, 6.4% K2SO4, and 32% Na2SO4 by
weight with a melting point of 8 0C.
A PCM composition according to an aspect of the present invention is obtainable
by mixing CaSO4, K2SO4, and Na2SO4, adding water (preferably filtered), and mixing until
obtaining a thickening uniform blend characterized with an increasing viscosity over time
and with a brittle however flowing texture.
An advantageous aspect of the compositions disclosed herein is that they have two
melting points, namely the compositions have a high melting point and a low melting point.
This allows for simultaneous use in the same composition, for both heating and cooling.
Thus, a first (lower) melting point can be utilized for cooling while a second (higher)
melting temperature can utilized to store heat for heating. The second melting point may
be above 30 0C. In some examples the second melting point is about 40 0C. A DSC
thermogram of a composition such as disclosed herein is shown in Fig. 1 where first
melting point (10) is around 6 0C and second melting point (20) is around 40 0C.19/3/2018 256626/2
1/1
FIGURE 18
13/09/2018 256626/4
Claims (16)
1. A composition of Phase Change Material (PCM), said composition including only a mixture of water and CaSO4, K2SO4 and Na2SO4, wherein said composition having first melting point between 4 to 8 0C, and second melting point above 30 0C.
2. A composition according to claim 1, wherein the content of CaSO4 of is 8%-15% by weight; K2SO4 content is 5-7% by weight; and the content of Na2SO4 is 20-35% by weight.
3. A composition according to claim 2, wherein CaSO4 content is 14.2% by weight; K2SO4 content is 6.7% by weight; and Na2SO4 content is 24% by weight.
4. A composition according to claim 2, wherein CaSO4 content is 8.3% by weight; K2SO4 content is 5.8% by weight; and Na2SO4 content is 29% by weight.
5. A composition according to any one of claims 1-4 having a first melting point of around 6 0C.
6. A composition according to claim 2, wherein CaSO4 content is 9% by weight; K2SO4 content is 6.4% by weight; and Na2SO4 content is 32% by weight.
7. A composition according to claim 1, having a first melting point of 8 0C.
8. A composition according to claim 1, wherein said second melting point is 40 0C.
9. A composition of Phase Change Material (PCM) obtained by the steps of: mixing CaSO4, K2SO4, and Na2SO4; adding water; and mixing until obtaining a thickening uniform blend with an increasing viscosity over time and with a brittle however flowing texture, wherein CaSO4 content is 8%-15% by weight; K2SO4 content is 5-7% by weight; and Na2SO4 content is 20-35% by weight.9 13/09/2018 256626/4
10. The composition of claim 9, having a first melting point between 4 to 8 0C and a second melting point above 30 0C.
11. A method for preparing of Phase Change Material (PCM), said method comprising: mixing CaSO4, K2SO4, and Na2SO4; adding water; and mixing until obtaining a thickening uniform blend with an increasing viscosity over time and with a brittle however flowing texture, wherein CaSO4 content is 8%-15% by weight; K2SO4 content is 5-7% by weight; and Na2SO4 content is 20-35% by weight.
12. A method according to claim 11, wherein said water are filtered.
13. A method according to claim 11, wherein said CaSO4 content is 14.2% by weight; said K2SO4 content is 6.7% by weight; and said Na2SO4 content is 24% by weight.
14. A method according to claim 11, wherein said CaSO4 content is 8.3% by weight; said K2SO4 content is 5.8% by weight; and said Na2SO4 content is 29% by weight.
15. A method according to claim 11, wherein said CaSO4 content is 9% by weight; said K2SO4 content is 6.4% by weight; and said Na2SO4 content is 32% by weight.
16. A method according to claim 11, wherein said PCM having first melting point between 4 to 8 0C and second melting point above 30 0C. For the Applicant Gold - Patents & Financial Services ltd.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IL256626A IL256626B (en) | 2017-12-27 | 2017-12-27 | Compositions of phase change materials for energy storage |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IL256626A IL256626B (en) | 2017-12-27 | 2017-12-27 | Compositions of phase change materials for energy storage |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| IL256626A true IL256626A (en) | 2018-02-28 |
| IL256626B IL256626B (en) | 2022-04-01 |
Family
ID=61274007
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IL256626A IL256626B (en) | 2017-12-27 | 2017-12-27 | Compositions of phase change materials for energy storage |
Country Status (1)
| Country | Link |
|---|---|
| IL (1) | IL256626B (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015085761A1 (en) * | 2013-12-12 | 2015-06-18 | 江苏启能新能源材料有限公司 | Phase change energy storage material |
-
2017
- 2017-12-27 IL IL256626A patent/IL256626B/en unknown
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015085761A1 (en) * | 2013-12-12 | 2015-06-18 | 江苏启能新能源材料有限公司 | Phase change energy storage material |
Also Published As
| Publication number | Publication date |
|---|---|
| IL256626B (en) | 2022-04-01 |
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