JP2001317887A - Thermal storage capsule - Google Patents

Abstract

PROBLEM TO BE SOLVED: To early release a supercooling degree of a latent heat thermal storage substance in a capsule by preventing a phase separation of the substance in the capsule by improving a heat transfer and thermal storage performance at a low cost. SOLUTION: The thermal storage capsule 1 seals the latent heat thermal storage substance therein and stores a heat exchanged with a heat conveying fluid 2 flowing in a circumference. The capsules 1 are easily uniformly dispersed in the fluid 2 by setting its specific gravity equal to that of the fluid 2. Thus, the capsules 1 are easily distributed in the fluid 2 without deviation. A wide heat transfer area is assured to easily efficiently heat exchange with the fluid. A capsule shape which flows, rotates and vibrates by flowing of the fluid 2 is formed. Thereby, a turbulence is generated in both the flows of the latent heat thermal storage substance liquid inside the capsule and the heat conveying fluid out of the capsule. The phase separation of the thermal storage substance is prevented, the supercooling degree is lowered, a heat transfer coefficient between the inner wall surface of the capsule and the thermal storage substance liquid is improved and a heat transfer coefficient between the outer wall surface of the capsule and the conveying fluid can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a heat storage capsule. More specifically, the present invention provides heat transfer performance and heat storage of a heat storage capsule that is provided in a heat storage tank or the like, exchanges heat by convection with a heat transfer fluid such as brine, and stores heat using a heat storage latent heat substance inside. Improving performance.

[0002]

2. Description of the Related Art (1) Prevention of phase separation A multi-component or hydrated salt latent heat storage material is a solid component of a substance having a different hydration number or a partial component precipitated in a cold storage (or heat release) mode. However, a phenomenon called "phase separation" which is likely to remain in a solid state even in the cooling heat (or heat storage heat) mode is likely to occur. When “phase separation” occurs, the solid-liquid phase change temperature (=
(Solidification / melting temperature) is different from the expected value, or a predetermined latent heat of fusion cannot be obtained.

[0003] In order to prevent phase separation, it is only necessary to agitate a part of the precipitated component or a solid of a substance having a different hydration number in a heat storage substance liquid.

(2) Reduction of degree of supercooling Many kinds of latent heat storage materials tend to cause a phenomenon called "supercooling" in which solids do not precipitate (= do not solidify) even when the temperature falls below the melting point during cold storage heat or heat release heat. . In particular, as the volume of the container enclosing the latent heat storage material is smaller, “supercooling” is more likely to occur. In order to perform cold storage heat or heat release by the precipitation and growth of a solid of a latent heat storage material, the “maximum supercooling degree” is a temperature difference between the melting point and the temperature at which the solid actually precipitates (= solidification start temperature = freezing start temperature). Is larger, the cooling with a lower temperature heat carrier fluid must be performed, so that the efficiency of the refrigerator for cooling the heat carrier fluid decreases.

Therefore, in order to reduce the degree of supercooling, at present, a foreign substance which is likely to be a nucleus for crystal formation of a latent heat storage material is added, or an impact is given by an electromagnetic field or ultrasonic waves.

[0006]

However, (1)
For phase separation, it is common to use a latent heat storage material enclosed in a heat storage capsule and to use the heat storage capsule stationary in the heat storage tank. near. At present, in order to reduce the influence of phase separation, the contact area between the remaining liquid and some of the precipitated components or substances with different hydration numbers can be increased by adding a gelling agent. Although the diffusion distance is reduced, the convection of the liquid is suppressed, and the heat transfer performance is reduced.

[0007] The method (2) is more reliable at a lower cost than the method of adding a foreign substance or giving an impact by an electromagnetic field or an ultrasonic wave as described above. A new method is desired.

Accordingly, the present invention provides a heat storage capsule capable of preventing phase separation by improving heat transfer and heat storage performance at low cost and quickly releasing the degree of supercooling of the latent heat storage material in the capsule. The purpose is to:

[0009]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a heat storage capsule for enclosing a latent heat storage material therein and storing heat exchanged with a heat carrier fluid flowing around. In the above, the specific gravity of the capsule is made equal to that of the heat transfer fluid so that the capsule is easily dispersed uniformly in the heat transfer fluid.

[0010] In this case, the heat storage capsules are evenly distributed in the heat transfer fluid, and a wide heat transfer area can be secured to efficiently exchange heat with the heat transfer fluid. For this reason, the heat transfer performance / heat storage performance of each heat storage capsule is prevented from lowering, and the heat transfer / heat storage performance as a whole is improved.

Therefore, according to the heat storage capsule, it is not necessary to suppress the convection of the heat transfer fluid, and the heat transfer performance between the capsule and the heat transfer fluid can be improved.

According to a second aspect of the present invention, there is provided a heat storage capsule for enclosing a latent heat storage material therein and storing heat exchanged with a surrounding heat transfer fluid, wherein the heat transfer fluid flows, rotates and vibrates due to the flow of the heat transfer fluid. It is formed in a capsule shape.

In this case, the heat storage capsule can flow and rotate only by the flow of the heat transfer fluid. For this reason, both the flow of the latent heat storage material liquid inside the capsule and the flow of the heat transfer fluid outside the capsule are disturbed, and the phase separation of the latent heat storage material inside the capsule can be prevented. In addition, the degree of subcooling of the latent heat storage material in the capsule is reduced, and the degree of supercooling can be released early by bringing the solidification start temperature close to the melting point. Furthermore, the heat transfer coefficient between the capsule inner wall surface and the latent heat storage material liquid and the heat transfer coefficient between the capsule outer wall surface and the heat transfer fluid can be improved.

According to a third aspect of the present invention, there is provided the first or second aspect.
In the heat storage capsule described above, the capsule shape is a non-spherical shape. Therefore, the heat storage capsule easily flows and rotates due to the flow of the heat transfer fluid, and easily agitates the internal latent heat storage material. For this reason, prevention of phase separation, reduction of the degree of supercooling, and improvement of the heat transfer coefficient facilitate the improvement of the heat transfer / heat storage performance. In addition, by making the capsules different in shape, it is possible to cause individual movement, and the turbulence of the flow is generated, so that the heat transfer / heat storage performance can be further improved.

The invention according to claim 4 is the first or second invention.
The heat storage capsule described above is formed in a columnar shape, and blades for causing the capsule to rotate axially by the flow of the heat transfer fluid are provided on the peripheral surface. In this case, the heat storage capsule rotates by the flow, causing turbulence in the flow of both the latent heat storage material liquid inside the capsule and the heat transfer fluid outside the capsule, preventing phase separation of the latent heat storage material inside the capsule and overcooling. The heat transfer coefficient between the capsule inner wall surface and the heat transfer fluid can be improved, and the heat transfer coefficient between the capsule outer wall surface and the heat transfer fluid can be improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on an example of an embodiment shown in the drawings.

FIG. 1 shows an embodiment of the present invention. The heat storage capsule 1 of the present invention has a known or new latent heat storage material sealed therein, and a plurality of heat storage capsules 1 are provided in a heat storage tank 4 through which a heat transfer fluid (brine) 2 as a heat medium flows as shown in FIG. The heat is exchanged with the heat transfer fluid 2 flowing around and the heat is stored inside.

The heat storage capsule 1 has a specific gravity equal to that of the heat transfer fluid 2 so that the heat storage capsule 1 can be easily dispersed uniformly in the heat transfer fluid 2. The capsule specific gravity in this case includes not only a case where the heat storage fluid 1 is exactly equal to the heat transfer fluid 2 but also a case where the heat storage capsule 1 has a specific gravity similar to the degree of uniform dispersion in the heat transfer fluid 2.

Specifically, the specific gravity of the general heat transfer fluid 2 is larger than 1, while the specific gravity of the general capsule material (for example, plastic such as polyethylene) is smaller than 1. Further, in order to prevent the capsule from being destroyed due to a change in the volume of the latent heat storage material during solidification and melting, air of several percent to ten and several percent (volume ratio) may be enclosed in the capsule.

As described above, when the specific gravity of the latent heat storage substance is smaller than that of the heat transfer fluid 2 (for example, ice), it is necessary to add a substance having a higher specific gravity to the heat storage capsule 1 or to attach the substance to the capsule surface. , Whereby the heat transfer fluid 2
It is also possible to obtain the effect of disrupting the flow of air. Conversely, when the specific gravity of the latent heat storage substance is larger than that of the heat transfer fluid 2 (for example, various hydrated salts), it is necessary to add a substance having a small specific gravity. In this case, however, the effect of disturbing the flow can be obtained. is there.

In the case of the present embodiment in which the capsule specific gravity is equal to that of the heat transfer fluid 2, the heat storage capsules 1 are distributed evenly in the heat transfer fluid 2 and a wide heat transfer area is secured to improve the efficiency between the heat storage capsule 1 and the heat transfer fluid. It becomes possible to exchange heat well. Therefore, a decrease in the heat transfer performance and heat storage performance of each heat storage capsule 1 is prevented, and the overall heat transfer and heat storage performance is improved. Therefore, according to the heat storage capsule 1, the convection of the heat transfer fluid is not suppressed, and the heat transfer performance between the capsule and the heat transfer fluid 2 can be improved.

Further, in the present embodiment, the heat storage capsule 1 is caused to flow by the heat carrier fluid 2 flowing around it.
It is formed in a non-spherical shape so as to rotate and vibrate. Thereby, the heat storage capsule 1 is connected to the heat transfer fluid 2 as shown in FIG.
In response to the flow, the fluid flows, rotates, vibrates, and the like, causing turbulence in the flow of both the latent heat storage material liquid inside the capsule and the heat transfer fluid 2 outside the capsule. Therefore, the phase separation of the latent heat storage material in the capsule can be prevented, the degree of supercooling of the latent heat storage material in the capsule is reduced, and the degree of supercooling is quickly increased by bringing the solidification start temperature close to the melting point. It is also possible to cancel. Further, the heat transfer coefficient between the capsule inner wall surface and the latent heat storage material liquid and the heat transfer coefficient between the capsule outer wall surface and the heat transfer fluid can be improved.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, in the present embodiment, the heat storage capsule 1 is made to have a substantially spherical shape but a non-spherical shape to cause flow, rotation, and vibration. However, the shape is not particularly limited to a spherical shape. As shown in FIG.

Here, both ends 1 a of the substantially cylindrical heat storage capsule 1 are rotatably and movably supported by the flow path wall 5 of the heat transfer fluid 2. In the present embodiment, both ends 1a, 1a of the heat storage capsule 1 are concave and convex, respectively.
The support is provided by engaging with the convex portion 5a and the concave portion 5b provided on the opposing surface of the flow path wall 5. In this case, as shown in the figure, a gap is provided between both end portions 1a, 1a and the convex portion 5a and the concave portion 5b to form a loosely engaged state so that the flow operation, the rotation operation, the vibration operation, etc. of the heat storage capsule 1 can be performed. I try not to disturb. Therefore, the heat storage capsule 1 can flow, rotate, vibrate, etc. within the movable range.

Further, on the peripheral surface of the heat storage capsule 1, there are provided blades 3 for causing a rotation operation by the flow of the heat carrier fluid 2. The blades 3 are preferably formed in an axially symmetrical shape capable of generating a rotating action in a certain direction, but may be non-axially symmetrical. In the present embodiment, as shown in the figure, a pair of spiral blades 3 whose diameter increases in the circumferential direction are provided on the peripheral surface of each heat storage capsule 1. In addition, the form shown here is only an example of the blade 3, and the shape and the number are not limited to such. Further, the capsule shape of the heat storage capsule 1 is not limited to a cylindrical or cylindrical shape.

Next, a third embodiment of the heat storage capsule 1 will be described. In the above-described second embodiment, the columnar heat storage capsule 1 is supported so that the axial direction is perpendicular to the flow direction of the heat transfer fluid 2, but in the third embodiment, the axial direction of the heat storage capsule 1 matches the flow direction. It is to let. In this case, a spiral blade 3 is provided on the peripheral surface of the heat storage capsule 1 as shown in FIG. 3, and the heat storage capsule 1 is rotated around the axis by the axial flow of the heat transfer fluid. This allows
As in the second embodiment, the flow of both the latent heat storage material liquid inside the capsule and the heat transfer fluid 2 outside the capsule is disturbed, and the heat transfer coefficient between the inner wall surface of the capsule and the latent heat storage material liquid and the outside of the capsule The heat transfer coefficient between the wall surface and the heat transfer fluid can be improved. In this case, the blade 3
May be a continuous spiral shape or a set of partial blades connected in a spiral shape.

[0027]

As is apparent from the above description, according to the heat storage capsule according to the first aspect, the specific gravity of the capsule is made equal to that of the heat carrier fluid to facilitate uniform dispersion, so that the heat storage capsule is biased in the heat carrier fluid. The heat transfer fluid can be efficiently exchanged with the heat transfer fluid while securing a large heat transfer area. For this reason, the heat transfer performance / heat storage performance of each heat storage capsule is prevented from deteriorating.
The heat storage performance is improved.

Therefore, according to the heat storage capsule, it is not necessary to suppress the convection of the heat transfer fluid, and the heat transfer performance between the capsule and the heat transfer fluid can be improved. In addition, the reliability is low and the heat storage material is not discarded.

According to the second aspect of the present invention, since the heat storage capsule has a capsule shape which flows, rotates and vibrates by the flow of the heat transfer fluid, both the latent heat storage material liquid inside the capsule and the heat transfer fluid outside the capsule are provided. Of the latent heat storage material in the capsule can be prevented from being separated. In addition, the degree of subcooling of the latent heat storage material in the capsule is reduced, and the degree of supercooling can be released early by bringing the solidification start temperature close to the melting point. Further, the heat transfer coefficient between the capsule inner wall surface and the latent heat storage material liquid and the heat transfer coefficient between the capsule outer wall surface and the heat transfer fluid can be improved. Moreover, the reliability is low at low cost, and there is no difference in the disposal of the heat storage material from the conventional one.

According to the third aspect of the present invention, since the shape of the capsule is non-spherical, it is easy to cause the heat transfer fluid to flow, rotate, etc., and to stir the internal latent heat storage material. For this reason, prevention of phase separation, reduction of the degree of supercooling, and improvement of the heat transfer coefficient facilitate the improvement of the heat transfer / heat storage performance.

According to the heat storage capsule of the present invention, the capsule is formed in a columnar shape, and the blade which causes the capsule to rotate axially by the flow of the heat transfer fluid is provided on the peripheral surface. The flow of both the latent heat storage material liquid and the heat transfer fluid outside the capsule can be disrupted. Therefore, prevention of phase separation of the latent heat storage material in the capsule and reduction of the degree of supercooling, improvement of the heat transfer coefficient between the capsule inner wall surface and the latent heat storage material liquid,
Further, the heat transfer coefficient between the capsule outer wall surface and the heat transfer fluid can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing the inside of a heat storage tank showing one embodiment of the present invention.

FIGS. 2A and 2B are views showing a second embodiment of the present invention, in which (A) a column-shaped heat storage capsule is viewed from the axial direction, and (B) a flow path wall and the heat storage capsule are viewed from the side.

FIG. 3 is a perspective view of a heat storage capsule showing a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal storage capsule 2 Heat transfer fluid 3 Blade

Claims (4)

[Claims] 1. A heat storage capsule for enclosing a latent heat storage material therein and storing heat exchanged with a surrounding heat transfer fluid, wherein the specific gravity of the capsule is equal to the heat transfer fluid, and A heat storage capsule characterized in that it is easy to disperse evenly. 2. A heat storage capsule which encloses a latent heat storage material therein and stores heat exchanged with a heat carrier fluid flowing therearound, wherein the capsule has a capsule shape which flows, rotates and vibrates due to the flow of the heat carrier fluid. A heat storage capsule characterized by the following. 3. The heat storage capsule according to claim 1, wherein the capsule shape is a non-true sphere. 4. The heat storage capsule according to claim 1, wherein the capsule has a columnar shape, and blades are provided on a peripheral surface of the capsule to generate axial rotation by the flow of the heat transfer fluid.