JPS59134494A - Heat accumulator - Google Patents

Abstract

PURPOSE:To accelerate transfer of heat of a fluid heat-accumulating substance sealed in capsules, by rotating and vibrating the capsules, in a capsule-type heat accumulator. CONSTITUTION:In each of capsules 2, round rods 4 of shape-stabilized polyethylene having a diameter of 2-5mm. are sealed as a fluid heat-accumulating substance together with a fluid 5 hardly compatible with polyethylene such as a silicone oil or water containing an anti-deterioration agent. When a hot heat- transmitting medium is introduced through an inflow port 1a of a tank 1 and is passed through the gaps between the capsules 2, it exchanges heat with the capsules 2, and when the temperature of the fluid 5 is raised to 135 deg.C, the round rods 4 are completely melted, and heat of melting is accumulated as latent heat in the capsules 2. In this heat accumulator, each of the capsules 2 is rotated in the interior of the tank 1 by a shaft 3, so that transfer of heat in the capsules 2 is accelerated, and heat-accumulating speed is increased.

Description

[Detailed Description of the Invention] This relates to a heat storage device for storing energy.
, 4) Heat storage using latent heat makes it possible to create a heat storage device that has a large heat storage density and releases high-quality thermal energy at a constant temperature of 1,000 degrees.

However, sufficient heat output cannot be obtained because heat transfer is inhibited due to phase change and solid phase precipitation during heat dissipation, or because reversible phase change becomes difficult to occur due to segregation, etc. The temperature decreases during heat dissipation.

This results in the loss of the active component of thermal energy, namely exergy and null.

In addition, when using the reaction heat of a reversible reaction, heat can be stored at a high density, but in general, when the reaction between powder and gas is used, heat transfer within the powder is insufficient. For this reason, a reversible reaction within a liquid is used, but since an organic substance with a large reaction entropy change is used, there is still a problem with heat transfer.

Therefore, in order to solve such problems, we aim to increase the total heat transfer area by micro-encapsulating the latent heat storage material, or use pentaerythritol, which does not fluidize, or stabilize the shape, which does not fluidize even when melted, by crosslinking, etc. Some inventions have been made in which polyethylene is used as a latent heat storage material and brought into direct contact with the heat medium, but in these heat storage devices, the heat medium is circulated to the outside of the heat storage tank to perform heat exchange, so it is necessary to use polyethylene as a latent heat storage material after the heat storage tank is installed. However, there are problems in that the heating medium needs to be filled on-site, the productivity is poor, and a large amount of expensive heating medium is required.

This invention was made in view of the current state of thermal storage technology, and provides a capsule type thermal storage device in which vibration, 1A rotation, etc. are applied to the capsule to promote heat transfer. be.

For organic latent heat storage materials such as polyethylene and pentaerythritol, nitrogen purging or sealing under vacuum is preferable to prevent oxidative deterioration. Similarly, for latent heat storage materials made of inorganic salts, contamination with moisture may deteriorate the properties. Many also require dry sealing.

By the way, a large heat storage tank is filled with these latent heat storage materials, and a shell/shell system that exchanges heat with a heat medium passing through heat transfer tubes is available.
The tube type latent heat storage device and the direct contact type heat storage device described above can be easily filled on-site.

Productivity is reduced because nitrogen substitution, depressurization, and drying are required.

Poor workability and seals break during use! , there is a risk of being exposed.

On the other hand, with capsule heat storage devices, filling the capsule, nitrogen replacement, depressurization, and drying can be done in one factory.
Productivity 2: It has good workability, and furthermore, it is possible to interchangeably produce a large number of capsules of the same specification and adjust the heat storage capacity by the number of capsules, and does not require a large amount of heat medium unlike the above-mentioned direct contact heat storage device.

However, there were difficulties in promoting heat transfer within the capsule.

FIG. 1 shows an outline of a capsule-type heat storage device showing an embodiment of the present invention, which was made to promote heat transfer.
1 is a tank for heat exchange, 1a is a heat medium inlet, 1b
is its outlet. Inside the tank 1, several capsules 2, 2, .

Inside the capsules 2, 2, there are shape-stabilized polyethylene round rods 4, 4 with a diameter of 2 to 5 mm, as shown in FIG.
. . . is cut into a length of 75 to 80% of the length of the capsule 2 and arranged so that the volume ratio is about 50 = 60%, and the anti-deterioration agent 2.6 Ethylene glycol, water, or silicone containing creol, etc.
It is sealed with fluid 5 such as oil.

Therefore, when a high-temperature heat medium is introduced from the inlet 1a and flows through the gaps between the capsules 2, 2...
Heat exchange is performed with the capsule 2, and the fluid 5 and the shape-stabilized polyethylene rods 4, 4, . . . are heated. Then, when the temperature of the fluid 5 rises by 135°CK, the shape-stabilized polyethylene round rods 4, 4... melt 9.
, the heat of fusion is stored in the capsule 2 as latent heat.

In the heat storage device of this invention, each of the capsules 2 (shirt)
3 to rotate within the tank 1, heat transfer within the capsule 2 is promoted and the rate of heat storage and release is increased.

In this embodiment, the capsule 2 is given rotational motion by the shaft 3 to promote heat transfer within the capsule 2. It goes without saying that vibration or rotation in the circumferential direction may be applied as long as the method promotes heat exchange.

The polyethylene sealed inside the capsule 2, especially polyethylene with a high degree of crystallinity, has a large latent heat (200 k
J/kg) No supercooling phenomenon is observed.

Although it is an excellent heat storage material that completely melts at 135°C and crystallizes at 127°C, it is preferable to stabilize its shape so that it does not flow even when melted.

Therefore, the surface or the entire surface can be cross-linked by irradiation with gamma rays, electron beams, or plasma.
(Japanese Patent Application No. 55-151845).

Crosslinking using a chemical crosslinking agent (Japanese Patent Application No. 149877/1983)
.

Silicone graft polymerization using a silane coupling agent, -'
No. 7), surface coating with a copolymer of ethylene and silicone (Japanese Patent Application No. 125312/1984, etc.) has been used to stabilize the shape.

In addition, a second heat storage material was prepared by forming polyethylene into a plate shape and laminating metal plates such as aluminum, which were also formed into a plate shape, and cutting them into pieces several mm thick, 58 m long, and 2 to 3 cm wide.
The capsule 2 may be filled together with a heat medium as shown in the figure.

In this case, there is a large difference in specific gravity between the heat storage material piece and the fluid serving as the heat medium, so when vibration or rotation is applied to the capsule 2, the agitation inside the capsule 2 becomes stronger and more sufficient heat transfer is achieved. It will be realized.

FIG. 3 is a cross-sectional view of an embodiment in which shape-stabilized polyethylene is made into a pellet-like heat storage material 4a and sealed together with a fluid 5 serving as a heat medium in a capsule 2 provided with a stirring plate 2a inside. .

In this case, pentaerythritol, which absorbs and releases heat through solid phase transition, is used as the pellet-shaped heat storage material 4a, and the heat medium is a hydrocarbon heat medium containing a carboxylic acid ester as a deterioration inhibitor (for example, Petroleum (N-Isam Co., Ltd., Nippon Steel Chemical Co., Ltd., Exxon Corporation
Caloria HT (trade name above) may be mixed.

Furthermore, inside the capsule 2, a substance that absorbs and releases heat through transfer and melting is microencapsulated with a polymer as a heat storage material (Japanese Patent Application Laid-open No. 53-93436), and as a heat medium. A fluid heat storage material mixed with a liquid that does not dissolve the microcapsules may be accommodated.

When such a capsule 2 rotates in the circumferential direction, the plates 2a arranged in a spiral pattern on the capsule wall effectively stir the fluid heat storage material made of the heat storage material and the fluid, thereby promoting heat transfer. It will be 4 days.

This embodiment is also effective for encapsulating other flowable heat storage materials. For example, when using a chemical reaction for heat storage in which cyclopentadiene releases reaction heat and becomes synchlopentadiene, and when reaction heat is applied, it reverts back to cyclopentadiene, heat transfer is difficult because it is an organic liquid. bad. However, if it is housed in the capsule 2 shown in FIG. 3 and rotated, heat transfer will be promoted and practical heat storage and release will become possible.

This can also be applied to other similar Teils-Fulder reactions.

Furthermore, in order to solve the problem of poor heat transfer in the solid phase of inorganic latent heat storage materials, a shell-tube heat storage device has been created that coexists with a liquid heat medium and stirs it. When rotation is applied using the capsule 2 shown,
A similar solution can be achieved with a capsule heat storage device.

In this case, Nacl −Kcl − is used as the latent heat storage substance.
A eutectic mixture of Mgc12 may be used and mixed with a eutectic alloy of lead and bismuth (melting point 125°C).

Furthermore, similarly, NaNO2-NaN is used as a latent heat storage material.
A eutectic mixture of O,-KN O3 is used and mixed with Gilotherm (trade name), an organic heat transfer medium.

Heat storage material Na2HPO4・12H20 and heat medium Ther
It can also be used in combination with mino160 (product name).

FIGS. 4(a) and 4(b) show an embodiment of a stirring bar inserted into a cylindrical capsule.

The stirrer 6 is made of metal and is formed into a T-shape with approximately the same dimensions as the inner periphery of the cylindrical capsule.
This is with the addition of a.

The dynamic heat storage material is efficiently stirred.

In the case of this embodiment, it can be applied not only to fluid heat storage materials containing pellet-like heat storage materials, but also to non-flowing latent heat storage materials that precipitate solid phases (e.g., calcium chloride hexahydrate, sodium sulfate). When used in the case of hydroxide hydrate), the solid phase deposited on the inner wall of the capsule tube during heat dissipation can be scraped off and good heat transfer can be maintained. In particular, for inorganic water salts, stirring has the effect of preventing segregation during heat dissipation.

FIGS. 5(a) and 5(b) show modified embodiments of the stirrer shown in FIGS. 4(a) and 4(b). This stirrer 7 is also part 1
Similar effects can be obtained by providing a weight 7a in the section.

FIGS. 6(a), (b), and (c) show three examples of stirrers that move longitudinally inside a cylindrical capsule to effect stirring.

The stirring bar 8 has the same diameter as the inner periphery of the capsule, and when the capsule is rotated in the axial direction as shown in the embodiment of FIG. Exercise and stir.

In this case, the ones shown in FIGS. 6(a) and 6(c) in particular are formed into a screw shape and perform rotational movement as well as longitudinal movement, so they are suitable for stirring fluid heat storage materials, and as described above. In this way, it is also possible to scrape off the solid phase deposited on the inner wall of the tube.

Although not shown, a small metal ball may be sealed inside the capsule as a stirrer, and the capsule may be stirred by applying vibration and rotation to promote heat transfer.

As explained above, in the heat storage device of the present invention, in a capsule-shaped heat storage device, vibration or rotation is applied to the fluid heat storage material sealed inside the capsule, and a stirrer is enclosed as necessary. Heat transfer can be promoted by preventing the phases from sticking together and actively stirring the mixture.

Therefore, according to this invention, the phenomenon in which the heat conduction of the heat transfer surface deteriorates due to the fixation of the same phase, the heat radiation rate decreases, and the extracted thermal energy decreases, is eliminated, and the temperature gradient due to heat transfer within the heat storage material is also eliminated. Since it is smaller, the heat storage/radiation rate increases, and in particular, the heat storage efficiency of latent heat is improved, which is a great effect.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing modification of a capsule-type heat storage device, Fig. 2 is a sectional view showing an example of a capsule M, and Fig. 3 is a sectional view of a cylindrical capsule filled with a movable heat storage material. ,H4
h (a), (b) + 94 s figure (a), (b)
6A is a cross-sectional view and a perspective view showing an example of a stirring bar inserted into a cylindrical capsule, and FIGS. 6(a) to (υ are perspective views showing other rows of stirring bars. tank; 2 is a capsule; 3 is a shaft; 4 is shape-stabilized polyethylene; 5 is a fluid serving as a heat transfer medium;
6.7.8 indicates a stirring bar. Figure 1 Figure 2? Figure 3 Figure 4 (a) (b) a Figure 5 (a) (b) Figure 6 (a) 11') 8

Claims (1)

[Scope of Claims] (1) A capsule-type heat storage device, characterized in that heat transfer of a fluid heat storage material sealed within the capsule is promoted by applying rotation and vibration to the capsule. (2) The heat storage device according to claim (1), characterized in that a stirrer is placed in the capsule. (1) The fluid heat storage material is formed of a mixture of a material that absorbs and releases latent heat through phase change and a fluid that hardly dissolves the material. The heat storage device described. (4) Polyx-tin as a fluid heat storage material,
The heat storage device according to claim 1, characterized in that the heat storage device is a mixture of a fluid that is hardly soluble in the polyethylene. (5) The heat storage device according to claim (1), characterized in that the fluid heat storage material is a mixture of pentaerythritol and a fluid that does not dissolve in pentaerythritol. (6) The heat storage device according to claim (1), wherein a mixture of an inorganic salt and an organic heat medium or a liquid metal is used as the fluid heat storage material. (7) The heat storage device according to claim (1), characterized in that a liquid material that absorbs and releases reaction heat through a reversible reaction is used as the fluid heat storage material.