JP3044305B1 - Heat storage device - Google Patents

Abstract

An object of the present invention is to provide a heat storage device having a small heat loss to the outside. SOLUTION: A heat storage tank 2 filled with a heat storage material 1 for storing heat given from the outside, and heat injection / extraction between the inside and outside of the heat storage tank by heat exchange between the heat storage material and a heat medium. And a heat exchanger 3. The heat exchanger 3 is piped so that heat is exchanged between the central portion 2a of the heat storage tank 2 and the outside, and the polymer absorbent 5 is dispersed in the peripheral portion 2b of the heat storage tank 2, for example. The natural convection of the heat storage material in the surrounding area is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage device for temporarily storing heat.

[0002]

2. Description of the Related Art The basic structure of a conventional heat storage device is shown in FIG.
1 to 13 are sectional views. The heat storage device shown in FIG. 11 has a heat storage tank 32 filled with a heat storage material 31 for storing heat, and a heat storage tank 3.
2 is provided with a heat exchanger 33 for exchanging heat with the outside. Water is often used for the heat storage material 31. There are various shapes of the heat storage tank 32 such as a rectangular parallelepiped and a column, but the operation as the heat storage device is the same. For example, in order to store the heat of the temperature Tx, the heat exchanger 3
3 is heated to Tx or more, and the temperature of the heat storage material 31 is set to Tx.
Increase to x. When the heat injection is completed, the heat storage device is allowed to stand still. If time elapses and heat is required outside, heat of temperature Tx is extracted from the heat storage material 31 to the outside by using the heat exchanger 33. Even when a substance that melts and solidifies during the heat injection / extraction process, such as paraffin, is used for the heat storage material 31, the basic operation of the heat storage device is the same as described above.

The heat storage device shown in FIG. 12 has heat storage tanks 42a and 42b filled with a heat medium 47 also serving as a heat storage material for storing heat.
The heat storage tank 42a is provided with a communication pipe 44a for connecting the heat storage tank 42a to the outside, the heat storage tank 42a and the heat storage tank 42b are connected by the communication pipe 44b, and the heat storage tank 42b is connected to the outside. Is provided. In many cases, water is used for the heat medium 47 which also serves as a heat medium for transferring heat between the outside and the heat storage material. The heat storage tank 42a and the heat storage tank 42b are appropriately formed. Although the case where the heat storage tank is composed of two tanks is shown here, the basic operation is performed in the following two tanks regardless of whether the heat storage tank is a single tank or a multi-tank of three or more tanks. Is the same as

[0004] In the operation of the heat storage device, for example, in order to store heat having a temperature of Tx, the heat medium 4 is connected through the communication pipe 44c.
7, and heat is externally applied to the heat medium 47 to reduce the temperature to T.
x or more, and inject into the heat storage tank 42a from the communication pipe 44a. The heat medium 47 removed from the heat storage tank 42a by this injection passes through the communication pipe 44b, reaches the heat storage tank 42b, is eventually sucked out of the communication pipe 44c, performs heat transport with the outside, and communicates again. Thermal storage tank 42 through pipe 44a
A cycle of returning to a is achieved. When the injection of heat into the heat storage tank is completed, the heat storage device is left standing. Time passes,
If heat is needed externally, the opposite direction to the heat injection process,
That is, the heat medium 47 is sucked out from the communication pipe 44a, and the heat is absorbed and used outside, and the heat medium 47 whose temperature has been reduced by the heat is returned from the communication pipe 44c to the heat storage tank 42b.
The heat medium 47 removed from the heat storage tank 42b by this return
Flows through the communication pipe 44b into the heat storage tank 42a, whereby the circulation of the heat medium 47 is achieved.

[0005] As described above, the reason for appropriately dividing the heat storage tank is to suppress the formation of a dead water area in which the flow tends to be stagnant inside the heat storage tank, and to circulate the heat medium 47 at the time of injecting and extracting heat. This is to ensure that the process is performed uniformly. When storing heat at a temperature lower than room temperature, the flow direction of the heat medium 47 in the heat injection / extraction process is reversed, but the basic operation is the same as described above.

On the other hand, in the heat storage device shown in FIG. 13, a heat storage material 51 mainly utilizing transition heat is filled in a small container 56, the small container 56 is stored in a heat storage tank 52, and the small container 56 is connected to the outside of the heat storage tank 52. The communication pipes 55a and 55b to be communicated are provided, and the heat medium circulating through the communication pipes 55a and 55b and the heat storage tank constitutes a heat exchange unit for performing heat exchange with the outside. In this case, the heat is mainly stored by the heat storage material 51 using the transition heat, and the heat medium 57 functions as a heat transport means, but is not necessarily not involved in the heat storage. The shape of the small container 56 is often spherical.

In this heat storage device, for example, when the temperature is T
To store the heat of x, the temperature becomes T through the communication pipe 55a.
The heat medium 57 above x is injected into the heat storage tank 52 from outside. The heat storage material 51 is connected to the heat medium 5 through the wall of the small container 56.
7 is heated by the heat released. Heat medium 5 injected
7 returns to the outside through the communication pipe 55b, is heated again to a temperature equal to or higher than Tx, and repeats the same circulation. When the heat injection is completed, the heat storage device is allowed to stand still. If heat is required externally, the direction of the heat injection process is reversed, that is,
The heat medium 57 is injected from the outside into the heat storage tank 52 from 5b.
The injected heat medium 57 is heated by the heat released from the heat storage material 51 via the wall of the small container 56. The heated heat medium 57 passes through the communication pipe 55a and returns to the outside, is used outside and has a temperature lower than Tx, and is again used as the communication pipe 55b.
And the same circulation is repeated.

[0008] When storing heat lower than room temperature,
In the heat injection / extraction process, the flow direction of the heat medium 57 injected from the outside is reversed, but the basic operation is the same as described above. In this configuration example, since the heat medium 57 injected and extracted from the outside passes through the gap between the small containers 56, the heat transfer area with respect to the heat storage material 51 increases, and the heat storage material 51 can be easily handled. It is often used for a heat storage device that uses transition heat such as paraffin as the heat storage material 51.

In the heat storage device shown in FIGS. 11 to 13, in the heat storage state, the temperature between the heat storage materials 31 and 51 and the heat medium 47 also serving as the heat storage material and the external environment surrounding the heat storage tanks 32, 42 and 52. If there is a difference, heat storage tanks 32, 42, 5
Heat transfer always occurs with the external environment through the second wall. Since the influence of heat radiation is usually small, if it is neglected, the heat loss Q of the heat storage material and the heat medium serving as the heat storage material (hereinafter referred to as the heat storage material) is

(Equation 1) It is represented by

Here, k is a heat transmittance determined by the material and structure of the heat storage tank, the surrounding wind speed, etc., and A is a contact area between the heat storage tank and a surrounding fluid (for example, air). To is the temperature of the environment outside the heat storage device, and Tx 'is the temperature at the surface where the heat storage material contacts the heat storage tank (the surface of the heat storage material). t is the elapsed time. k
Since A and A can usually be regarded as constant regardless of time, equation (1) can be approximated as follows.

(Equation 2)

The heat storage method mainly uses the sensible heat of the heat storage material 31 and the heat medium 47 as shown in FIGS. 11 and 12, and the heat storage method mainly uses the heat storage material as shown in FIG. Lumber 5
In some cases, in which either sensible heat or transition heat is used, for example, in order to store heat at the temperature Tx, the temperature Tx 'of the surface of the heat storage material is set to a temperature equal to or higher than Tx. Need to be kept. However, as the temperature difference between the surface temperature Tx 'of the heat storage material and the external environmental temperature To becomes larger and the storage time becomes longer, the heat loss represented by the formula (2) increases, and the heat storage efficiency drops remarkably. Cause. Therefore, to reduce the heat loss from the heat storage tank in equation (2), the heat transfer rate k and the surface area A are reduced,
It is necessary to shorten the time t or reduce the difference between the surface temperature Tx 'of the heat storage material and the environmental temperature To. Heat transmission rate k
Attempts have been made to attach a heat insulating material around the heat storage tank as a method of reducing the temperature. As a method for reducing the surface area, attempts have been made to make the heat storage tank into a shape having a small surface area per unit volume, such as a cube or a sphere.
As a method for reducing the time t, attempts have been made to optimize system control of the heat utilization system after re-extraction of heat, but the time term and the temperature term are the original purposes of heat storage. It is not of the nature that can be changed significantly.

On the other hand, in the examples shown in FIGS. 11 and 12, the temperature of the heat storage material gradually approaches the temperature of the external environment from a portion closer to the wall surfaces of the heat storage tanks 32 and 42, so that a temperature difference occurs in the heat storage material. I do. Normally, a substance expands or contracts when the temperature changes, so if a temperature difference is created in the heat storage material, a density difference will occur there, causing a gravity difference, and as a result, natural convection will occur in the heat storage material. A movement called evoked. Therefore, natural convection occurs from the vicinity of the wall surfaces of the heat storage tanks 32 and 42 having the largest temperature difference from the external environment, that is, from the outside of the heat storage material, and the natural convection spreads throughout the heat storage material. At the same time as the heat storage material that is closer to the external environment temperature than the stored heat flows in from the surface side, the stored heat moves to the surface of the heat storage material, whereby the heat is constantly transferred to the external environment through the wall surface of the heat storage tank. Due to the movement, a large heat loss occurs in the heat storage material.

In the heat storage device shown in FIG. 13, the natural convection of the heat storage material 51 in the heat storage tank 52 is suppressed by the small container 56 in the heat storage process.
Since natural convection is generated in the heat medium 57 staying in the heat storage medium 2, the heat medium 57 can be said to be the same as the heat storage materials 31 and 41 of the heat storage device in FIGS. In this way, the temperature changes from the heat storage material closer to the wall surface of the heat storage tank to the temperature close to the external environment, so that the heat transfer process is performed outside and inside the heat storage material (when the heat storage tank is a sphere, (In the radial direction), a natural convection occurs in the heat storage material, so that heat is always transferred between the heat storage material and the external environment through the wall surface of the heat storage tank. Will result in heat loss.

In any of the conventional heat storage devices shown in FIGS. 11 to 13, since the heat storage material easily flows in any case, the temperature difference due to heat exchange is caused not only in the heat preservation process but also in the heat injection / extraction process in particular. As a result, natural convection over the entire heat storage material is likely to occur, and as a result, the heat transfer rate k in Equation (2) increases, heat loss from the heat storage material to the outside increases, and one of the factors that lowers the heat recovery rate is as follows. Had one.

It is known that the heat balance at a certain position inside the heat storage material is expressed by the following equation.

(Equation 3) Here, x, y, and z are rectangular coordinates, t is time, u, v, and w are x, y, and z-direction components of speed, e is the internal energy of the heat storage material, λ is the thermal conductivity of the heat storage material, p Is the pressure of the heat storage material, qi is the internal heat generation of the heat storage material, ρ is the density of the heat storage material, and η is the viscosity function of the heat storage material.

Equation (3) indicates that the change in the internal energy of the heat storage material per unit time / volume is caused by the heat flowing from the surroundings due to the movement of the heat storage material, the heat flowing from the surroundings due to the heat conduction of the heat storage material, and the heat storage material itself. , Heat generated by a change in pressure of the heat storage material, and heat generated by viscous friction of the heat storage material. It is generally known that heat transfer due to natural convection is more intense than heat transfer due to heat conduction or the like. The heat transfer inside the heat storage material will also increase. Therefore, in the heat storage device, in order to suppress the heat loss of the heat storage material, the temperature difference between the surface of the heat storage material and the external environment, and at least the surface of the heat storage material and the heat storage material for injecting and extracting heat with the outside. It is necessary to consider the suppression of heat transfer to and from the inner part.

[0017]

SUMMARY OF THE INVENTION The present invention has been made to improve the heat loss from the heat storage material as described above, and has reduced the temperature difference between the surface of the heat storage material and the external environment; By suppressing the heat transfer between the surface of the heat storage material and the inside of the heat storage material for injecting / extracting heat with the outside, the influence of the external environment on the inside of the heat storage tank is reduced. It is another object of the present invention to provide a heat storage device capable of suppressing heat loss to the outside.

[0018]

According to a first aspect of the present invention, there is provided a heat storage device, comprising: a heat storage tank filled with a heat storage material for storing heat applied from the outside; Heat exchange between the inside and outside of the heat storage tank
Heat exchange means for performing extraction, the heat exchange means to perform heat exchange between the central part of the heat storage tank and the outside, or, sequentially to the central part and the peripheral part of the heat storage tank It is characterized in that heat exchange is performed with the outside or heat exchange is individually performed, and a means for suppressing natural convection of the heat storage material is provided around the heat storage tank. . Further, a second heat storage device of the present invention for solving the above-mentioned problem is characterized in that a heat storage tank filled with a heat medium also serving as a heat storage material for storing heat given from the outside, Heat transfer means for injecting and extracting heat between the inside and outside of the heat storage tank, wherein the heat transfer means is arranged to perform heat transfer between a central portion of the heat storage tank and the outside. The heat storage tank further includes a suppression means for suppressing natural convection of the heat medium around the heat storage tank.

In the above heat storage device, the suppressing means can be constituted by dispersing the liquid absorbing material in the heat storage material or the heat medium in the peripheral portion of the heat storage tank. In addition, the suppressing means gives the heat storage material or the heat medium in the peripheral portion of the heat storage tank a property of increasing the viscosity by applying a voltage, and arranges the electrodes to face each other so as to sandwich the peripheral portion of the heat storage tank. Means for supplying electricity between the electrodes shall be provided, or a magnet that gives the heat storage material or heat medium in the peripheral portion of the heat storage tank a property of increasing viscosity by magnetic force and acts on the peripheral portion of the heat storage tank with a magnetic force. In addition, a barrier may be provided around the heat storage tank to prevent natural convection of the heat storage material or the heat medium. In the heat storage device, a means for promoting heat transfer may be provided between the central portion and the peripheral portion in the heat storage tank.

In the heat storage device having the above-mentioned structure, the heat exchange means for exchanging heat with the central portion of the heat storage tank or the heat transport means for transporting heat to the central portion stores heat at a temperature higher than the temperature required for heat extraction. The heat is transmitted to and stored in a heat storage material or a heat medium mainly stored in a peripheral portion of the heat storage tank, and the stored heat is extracted from a central portion of the heat storage tank as needed. When heat is injected or extracted, heat is exchanged mainly in the central part of the heat storage tank where convection is easy, so that large heat transfer due to natural convection heat transfer is added to heat transfer due to heat conduction. Exchange is performed efficiently. In addition, when storing heat, since heat transfer usually occurs between the surrounding portion of the heat storage tank and the external environment, the temperature of the heat storage material or the heat medium gradually increases from a position closer to the heat storage tank. Attempts to approach the temperature of the external environment. Therefore, in this heat storage tank, a temperature difference occurs due to heat transfer, and natural convection tends to be generated from a heat storage material or a heat medium closer to the heat storage tank.

At this time, the natural convection tends to expand its movement to the heat storage material located at the entire peripheral portion and the central portion of the heat storage tank, thereby causing a large heat transfer. Suppression means provided in the peripheral portion of the heat storage tank for suppressing natural convection makes it difficult to transfer large heat in the peripheral portion due to natural convection.

As shown in the above equation (2), the heat loss Q of the heat storage material increases as the difference (Tx'-To) between the temperature of the surface of the heat storage material and the temperature of the external environment surrounding the heat storage tank increases. Also, the heat transfer rate (k) increases as the heat transfer rate (k) increases. As described above, in the present invention, natural convection is suppressed in the peripheral portion of the heat storage tank, and natural convection generated on the surface of the thermal storage material in the peripheral portion of the thermal storage tank is entirely generated in the thermal storage material in the peripheral portion of the thermal storage tank. Since the expansion is prevented, the heat transfer and heat transfer rate (k) due to convection between the surrounding portion of the heat storage tank and the external environment are reduced, and the heat in the heat storage material in the surrounding portion of the heat storage tank is reduced. Since movement to the surface of the heat storage material is suppressed, a large temperature gradient is formed in the heat storage material in the surrounding portion, and the temperature difference between the surface of the heat storage material and the external environment gradually decreases. Therefore, the heat loss from the inside of the heat storage tank to the outside environment can be suppressed while keeping the temperature inside the heat storage tank substantially.

In the present invention, the means for suppressing natural convection can be constituted by dispersing a liquid-absorbing substance in a heat storage material or a heat medium in a peripheral portion of the heat storage tank. The volatile substance absorbs a part of the heat storage material or the heat medium and expands, so that it stays in a three-dimensional mesh shape around the heat storage tank. In other words, the heat storage material or the like fills the gap between the liquid-absorbing substances and becomes difficult to move. Heat loss can be reduced.

As the above-mentioned suppressing means, the heat storage material or the heat medium in the peripheral portion of the heat storage tank is made to have a property of increasing the viscosity by applying a voltage, and electrodes are arranged so as to sandwich the peripheral portion of the heat storage tank. When a voltage is applied to the electrodes, an electric field is generated in the surrounding area and the viscosity of the heat storage material increases, so that the free movement of the heat storage material is hindered. Natural convection in a part can be suppressed. Further, as the suppression means, a heat storage material or a heat medium in a peripheral portion of the heat storage tank,
In addition to having the property of increasing the viscosity due to the magnetic force, if a magnet is provided around the heat storage tank to apply a magnetic force, the action of the magnetic field by the magnet increases the viscosity of the heat storage material or the heat medium, Since free movement of the heat storage material is hindered, natural convection in the surrounding portion can be suppressed.

Further, the suppression means may be a barrier provided around the heat storage tank and hindering natural convection of the heat storage material or the heat medium. In this case, the barrier may move the heat storage material or the heat medium. By properly arranging this barrier, the speed of movement of the heat storage material can be much slower than without obstacles, and consequently natural convection can be suppressed. Can be. Further, in the present invention, a means for promoting heat transfer is provided between the central part and the peripheral part in the heat storage tank, and when the heat is quickly injected or extracted into the heat storage tank, the center is required. The heat transfer between the portion and the surrounding portion where the heat transfer from the central portion is difficult due to the natural convection suppressing means can be quickly performed.

The heat exchanging means in the present invention can be arranged so that heat is exchanged between the central portion and the peripheral portion of the heat storage tank in order between the outside and the outside. With the residual heat after heating or cooling the central part of the heat storage tank, the surrounding part can be further heated or cooled.On the contrary, at the time of heat extraction, after preheating or precooling the heat exchange means in the peripheral part of the heat storage tank, Heating or cooling can be further performed at the central portion, so that heat exchange between the heat storage device and the external environment can be performed quickly and efficiently. Further, the heat exchange means may be arranged so as to individually perform heat exchange between the central portion and the peripheral portion of the heat storage tank between the outside and the heat storage tank. Depending on the temperature of the heat to be injected into the central part or the surrounding part, whichever is appropriate, heat or cool, and conversely, when extracting heat, according to the temperature of the heat required from the outside,
Heat can be exchanged in the central portion or the peripheral portion of the heat storage tank, whichever is appropriate. This makes it possible to efficiently exchange heat between the heat storage device and the outside in a wider range.

[0027]

[First Embodiment] FIG. 1 is an example of a sectional view of a heat storage device according to the present invention. The heat storage device includes a heat storage material 1 for storing heat in a heat storage tank 2 and a heat exchanger 3 as a means for performing heat exchange between the heat storage tank 2 and the outside.
Is provided. Various materials can be used as the heat storage material 1 according to the required heat storage temperature, and may be a material that changes phase during the heat injection / extraction process.
In the drawings, the heat storage tank 2 is represented as a rectangular parallelepiped. However, the material and shape of the heat storage tank 2 are not limited as long as the heat storage tank 2 is stable with respect to the heat storage material 1. It can be shaped. In the heat storage tank 2, the inner space is divided into two parts by a net 4 into a central part 2a and a peripheral part 2b around the central part 2a, that is, in the heat storage tank 2, the central part 2a and the peripheral part 2b are separated. A net 4 is stretched around the boundary, and the central portion 2a is surrounded by the peripheral portion 2b through the net 4.
Surrounded by The polymer liquid-absorbing substance 5 is dispersed only in the heat storage material 1 in the surrounding portion 2b.

The net 4 comprises a heat storage material 1 and a liquid absorbing material 5
And the liquid-absorbing substance 5 is
The material and the structure are not limited as long as the material and the structure are prevented from being mixed into a. For example, when the diameter of the liquid-absorbing substance 5 to be dispersed in the surrounding portion 2b is larger than 0.5 mm, a mesh having a finer eye interval, that is, a mesh of about 50 to 100 mesh or more may be used. Thereby, it is possible to maintain the liquid absorbing substance 5 so as not to enter the central portion 2a. The heat exchanger 3 is provided as a means for performing heat exchange between the outside of the heat storage device and the heat storage material 1 in the central portion 2a. The material and structure are not limited. The liquid absorbing substance 5 is chemically and thermally stable with respect to the heat storage tank 2 and the net 4, and increases the viscosity of the heat storage material 1 in the surrounding portion 2b, thereby constituting a natural convection suppressing means. The material and the shape are not limited as long as it is possible. For example, various substances such as highly water-absorbing polymer material particles such as a starch-acrylonitrile graft polymer hydrolyzate and fibers such as absorbent cotton can be applied.

Next, the operation of the heat storage device shown in FIG. 1 in the case where the temperature is stored higher than the environment outside the heat storage device will be described. In the heat injection process, the heat storage material 1 filled in the heat storage tank 2 using the heat exchanger 3 is used to heat the heat storage material 1 located in the central portion 2a to increase the temperature. When the temperature of the heat storage material 1 in the central portion 2a rises, the temperature difference between the central portion 2a and the peripheral portion 2b increases, so that heat moves from the central portion 2a toward the peripheral portion 2b and is located in the peripheral portion 2b. The heat storage material 1 is gradually heated. In the process of injecting and extracting heat, the surrounding portion 2b passes through the wall of the heat storage tank 2
Although heat transfers to the external environment surrounding the heat storage tank 2, for the sake of simplicity, heat loss to the outside will be described only in the following storage process.

In the process of storing heat, heat moves from the central portion 2a to the external environment surrounding the heat storage tank 2 through the peripheral portion 2b and the heat storage tank 2, so that the temperature of the heat storage material 1 gradually decreases. As described above, since the temperature of the heat storage material 1 changes from the peripheral portion closer to the heat storage tank 2, a temperature difference is generated in the heat storage material 1 in the direction from the center to the periphery in the heat transfer process, When the heat storage material 1 flows freely, natural convection is induced inside the heat storage material 1. It is well known that the strength of this natural convection is governed by the Grashof number Gr defined by the following equation.

[0031]

(Equation 4) l is a typical length (for example, the height of the vertical wall surface of the heat storage tank 2) g is a gravitational acceleration β is a coefficient of body expansion of the heat storage material 1 ΔT is a temperature difference formed in the heat storage material 1 ν is a dynamic of the heat storage material 1 Viscosity coefficient

If there is no transfer of the substance in the heat storage material 1, the heat transfer between the heat storage material 1 and the heat storage tank 2 is caused by the difference between the constituent molecules / atoms in the heat storage material 1 and the heat storage tank 2 which are adjacent to each other. Although it depends only on direct heat transfer, that is, heat conduction, when there is natural convection in the heat storage material 1 as described above, in addition to heat conduction, natural convection, that is, rapid and large heat transfer due to material movement ( Heat transfer) and free and active heat transfer occurs. It is well known that the strength of heat transfer between the fluid and the solid wall is governed by the Nusselt number Nu defined by the following equation:

[0033]

(Equation 5) h is the heat transfer coefficient between the heat storage material 1 and the heat storage tank 2 x is the distance from below the vertical wall surface of the heat storage tank 2 λ is the heat conductivity of the heat storage material 1 Pr is the Prandtl number of the heat storage material 1 Pr = ν / α (Α is the thermal diffusivity of the heat storage material 1) C and m are constants determined by the state of the wall surface

The right side of equation (5) indicates that the Nusselt number Nu is a function of the Prandtl number Pr and the Grashof number Gr. From equations (4) and (5), the heat transfer coefficient between the heat storage material 1 and the heat storage tank 2 is:

(Equation 6) It can be seen that

Equation (6) indicates that the heat transfer coefficient h increases as the thermal conductivity and coefficient of thermal expansion of the heat storage material 1, the length of the heat storage tank 2 in the vertical direction, or the temperature difference between the heat storage material 1 and the heat storage tank 2 increase. The heat transfer between the heat storage material 1 and the heat storage tank 2 increases as the heat transfer between the heat storage material 1 and the heat storage tank 2 increases, and conversely, as the thermal diffusivity and the kinematic viscosity coefficient of the heat storage material 1 increase. This shows that heat transfer is reduced. The amount of heat transfer from the heat storage material 1 to the outside follows the equation (2). However, as the heat transfer coefficient h between the heat storage material 1 and the heat storage tank 2 increases, the heat transfer rate k sharply reacts and increases. Accordingly, heat loss from the heat storage material 1 to the external environment increases.

In the heat storage device of this embodiment, the surrounding portion 2b
Surrounding part 2b by the polymer absorbent material 5 dispersed in
Is subjected to the same action as increasing the viscosity ν, and natural convection becomes difficult as shown by the equation (4). As a result, the heat storage material 1 is shown by the equation (6). Thus, the heat transfer between the heat storage material 1 and the heat storage tank 2 in the surrounding portion 2b is reduced, and the heat loss to the outside is also reduced.

In the heat extraction process, heat corresponding to the temperature of the heat storage material 1 can be extracted from the heat storage tank 2 using the heat exchanger 3. Central part 2 with heat extraction
a, the temperature difference between the central portion 2a and the peripheral portion 2b increases.
b moves toward the central portion 2a,
The heat storage material 1 in b is gradually cooled. In the case of storing heat at a lower temperature than the external environment of the heat storage device, the basic operation is the same as described above, except that the direction of the flow of heat and the level of the temperature are reversed.

Embodiment 2 FIG. 2 is a cross-sectional view of another embodiment of the heat storage device according to the present invention. This heat storage device accommodates a heat storage material 1 for storing heat in a heat storage tank 2, but unlike the case of FIG. 1, a central portion 2 a surrounded by a net 4 of the heat storage tank 2 and the outside of the heat storage device. Are connected by two communication pipes 6a and 6b through which the heat medium 8 also serving as a heat storage material flows in and out. The materials and structures of these communication tubes 6a and 6b are not limited as long as they are stable with respect to the heat medium 8. Other configurations are the same as those in the embodiment of FIG.

Next, the operation in the case where the heat storage device of FIG. 2 stores a higher temperature than the external environment will be described.
In the heat injection process, the heat medium 8 is sucked from the communication pipe 6b and heated by an external heat source. Heat medium 8 heated outside
Is returned to the heat storage tank 2 using the communication pipe 6a. By repeating the circulation of the heat medium 8 between the heat storage tank 2 and the outside of the heat storage device as necessary, the temperature of the heat medium 8 in the central portion 2a increases, that is, heat is stored in the heat storage tank 2. Will be injected. When the temperature of the heat medium 8 in the central portion 2a increases, the temperature difference between the central portion 2a and the peripheral portion 2b increases, so that heat moves from the central portion 2a toward the peripheral portion 2b, and the peripheral portion 2b Is gradually heated. In the process of injecting and extracting heat, the surrounding portion 2b passes through the wall of the heat storage tank 2
Although heat transfers to the external environment surrounding the heat storage tank 2, for the sake of simplicity, heat loss to the outside will be described only in the following storage process.

In the process of storing heat, heat moves from the central portion 2a through the peripheral portion 2b and the heat storage tank 2 to the external environment surrounding the heat storage tank 2, so that the temperature of the heat medium 8 gradually decreases. However, as in the operation of FIG.
Around the surrounding part 2 by the polymer liquid absorbing substance 5 dispersed in
The heat medium 8 at b is subjected to the same action as increasing the viscosity ν, and natural convection becomes difficult as shown in the equation (4). As a result, as shown in the equation (6), The heat transfer between the heat medium 8 in the surrounding portion 2b and the heat storage tank 2 is reduced, and the heat loss to the outside is also reduced.

In the process of extracting heat, the heat medium 8 contained in the heat storage tank 2 is sucked out through the communication pipe 6a and used outside as a heat source at the temperature of the heat medium 8. The heat medium 8 cooled outside by using heat is returned to the heat storage tank 2 through the communication pipe 6b. When the temperature of the heat medium 8 in the central portion 2a decreases with the extraction of heat, the temperature difference between the central portion 2a and the peripheral portion 2b increases, so that heat moves from the peripheral portion 2b toward the central portion 2a. The heat medium 8 in the surrounding portion 2b is gradually cooled. In addition, when storing heat at a temperature lower than the environment outside the heat storage device, the basic operation is the same as that of the temperature, the flow of heat, and the direction of extracting and injecting the heat medium 8 are reversed. Same as above.

Embodiment 3 FIG. 3 is a sectional view of another embodiment of the heat storage device according to the present invention. In this heat storage device, in a heat storage tank 2 having the same configuration as the embodiment of FIG. 2, two communication pipes 6a and 6b are provided between a central portion 2a of the heat storage tank 2 surrounded by a net 4 and the outside of the heat storage device. The heat storage materials 1a, 1b housed in the central portion 2a and the peripheral portion 2b of the heat storage tank 2 are housed in small containers 7a, 7b, respectively, and heat is stored between the small containers 7a in the center portion 2a. The heat medium 8 is circulated between the heat storage material and the outside by circulating the heat medium 8 between the outside of the device and the communication pipes 6a and 6b. Various materials can be used as the heat storage materials 1a and 1b according to the required heat storage temperature, and may be a material that changes phase during the heat injection / extraction process. Also, the central portion 2 of the heat storage tank 2
The heat storage materials 1a and 1b of the a and the surrounding portion 2b may be the same material or different materials.

In the drawings, the small containers 7a, 7a of this embodiment are shown.
b is a sphere, but the material and shape are not limited as long as it is stable against the heat storage materials 1a and 1b and the heat medium 8, and the central portion 2a and the peripheral portion 2b are small containers. May be different or the same.
The material of the heat medium 8 is not limited as long as it is stable in the temperature range used.

Next, the operation of the heat storage device shown in FIG. 3 when the heat storage device stores a higher temperature than the external environment will be described. In the heat injection process, first, the communication pipe 6b
The heat medium 8 staying in the heat storage tank 2 is sucked out and heated by an external heat source. The heat medium 8 heated outside is returned to the heat storage tank 2 through the communication pipe 6a. By repeating such circulation of the heat medium 8 between the heat storage tank 2 and the external environment as necessary, heat is stored from the heat medium 8 through the wall of each small container 7a housed in the central portion 2a of the heat storage tank 2. Heat moves to the material 1a, and the temperature of the heat storage material 1a increases. That is,
Heat is injected into the heat storage tank 2.

When the temperature of the heat storage material 1a in the central portion 2a rises, the temperature difference between the central portion 2a and the peripheral portion 2b increases, so that heat moves from the central portion 2a toward the peripheral portion 2b, The heat storage material 1b in 2b is gradually heated. In the heat injection / extraction process, heat is transferred from the surrounding portion 2b through the wall of the heat storage tank 2 to the external environment surrounding the heat storage tank 2. To simplify the explanation, the heat loss to the outside is described below. Only the preservation process will be described.

In the process of storing heat, heat moves from the central portion 2a to the external environment surrounding the heat storage tank 2 through the peripheral portion 2b and the heat storage tank 2, so that the temperatures of the heat storage materials 1a and 1b gradually decrease. However, as in the operation of FIG. 1, the heat absorbing medium 5 in the surrounding portion 2b is subjected to the same action as the increase in the viscosity ν by the polymer liquid-absorbing substance 5 dispersed in the surrounding portion 2b. 4), natural convection becomes difficult, and as a result, as shown in equation (6), heat transfer between the heat medium 8 in the surrounding portion 2b and the heat storage tank 2 decreases. Therefore, heat loss to the outside is also reduced.

In the process of extracting heat, the heat medium 8 contained in the heat storage tank 2 is sucked out using the communication pipe 6a, and is used as a heat source at the temperature of the heat storage material 1a outside, and is cooled outside by utilizing heat. The heated heat medium 8 is returned to the heat storage tank 2 through the communication pipe 6b. When the temperature of the heat storage material 1a in the central portion 2a decreases with the extraction of heat, the temperature difference between the central portion 2a and the peripheral portion 2b increases, so that heat moves from the peripheral portion 2b toward the central portion 2a. Then, the heat storage material 1b in the surrounding portion 2b is gradually cooled. In addition, even when storing heat at a temperature lower than that of the external environment of the heat storage device, the basic operation is the same as described above, except that the direction of the heat flow is reversed with the temperature.

Embodiment 4 FIG. 4 is a sectional view of another embodiment of the heat storage device according to the present invention. This heat storage device is shown in FIG.
And a heat insulating layer 9 is provided outside the heat storage tank 2. The material and structure of the heat insulating layer 9 are not limited as long as the inner surface has stability with respect to the heat storage tank 2 and the outer surface has stability with respect to the external environment. Note that the same reference numerals in FIG. 4 denote the same parts as in the embodiment of FIG. 1, and a description thereof will be omitted.

Next, the operation of the heat storage device shown in FIG. 4 when the heat storage device stores a higher temperature than the external environment will be described. The operation in the heat injection process is basically the same as in the first embodiment. In the process of storing heat, the central part 2a
Then, the heat moves to the external environment surrounding the heat storage tank 2 through the surrounding portion 2b and the heat storage tank 2, so that the temperature of the heat storage material 1 gradually decreases. However, similarly to the operation of FIG. 1, the polymer dispersed in the peripheral portion 2b causes the heat medium 8 in the peripheral portion 2b to undergo the same operation as increasing the viscosity ν, and as shown in Expression (4). Natural convection becomes difficult,
As a result, as shown in the equation (6), heat transfer between the heat storage material 1 and the heat storage tank 2 in the surrounding portion 2b is reduced, and accordingly, heat loss to the outside is also reduced. that time,
Since the heat conductivity of the heat insulating layer 9 is smaller than that of the heat storage tank 2, the heat transmittance k in the equation (2) can be reduced, and a heat storage device with a small heat loss can be provided.

The operation of the heat extraction process is basically the same as that of the first embodiment.
Is the same as In the case of storing heat at a temperature lower than the environment outside the heat storage device, the basic operation is the same as described above, except that the direction of heat flow is opposite to the temperature. In this embodiment, the case where the heat storage tank and the like are the same as in the first embodiment is shown. However, the present invention can be similarly applied to the structures described in the second and third embodiments.

Embodiment 5 FIG. 5 is a cross-sectional view of another embodiment of the heat storage device according to the present invention. This heat storage device is shown in FIG.
Is provided with a heat storage tank 2 and a heat exchanger 3 similar to those of the first embodiment, except that an electrode 4a is provided instead of the net 4 extending around the boundary between the central part 2a and the peripheral part 2b of the heat storage tank 2. I have. That is, the electrode 4a is provided so that the central portion 2a and the peripheral portion 2b are spatially separated. In addition, an electrode 4b extends around the inner surface of the heat storage tank 2. These electrodes 4a and 4b are arranged facing each other so as to sandwich the peripheral portion 2b, and are connected to the power supply 11 respectively.
Is filled with an electrorheological fluid 10 acting as a heat storage material. The electrorheological fluid 10 has a property of increasing the viscosity when a voltage is applied.

The materials and structures of the electrodes 4a and 4b are not limited as long as a uniform electric field can be generated in the peripheral portion 2b by applying a voltage to the power supply 11, and may be, for example, a mesh. The material and composition of the electrorheological fluid 10 are not limited as long as it is stable with respect to the heat storage tank 2, the heat exchanger 3, and the electrodes 4a and 4b. For example, various substances can be applied depending on the required heat storage temperature, such as a liquid in which carbon powder is suspended.

Next, the operation of the heat storage device shown in FIG. 5 when storing a temperature higher than the environment outside the heat storage device will be described. In the process of injecting heat, the heat exchanger 3 heats the electrorheological fluid 10 contained in the heat storage tank 2 at the central portion 2a to increase the temperature. When the temperature of the electrorheological fluid (heat storage material) 10 in the central portion 2a increases, the temperature difference between the central portion 2a and the peripheral portion 2b increases, so that heat moves from the central portion 2a to the peripheral portion 2b, The electrorheological fluid 10 in the surrounding portion 2b is gradually heated.

When the amount of heat supplied from the outside to the heat storage device is less than the amount of heat diffused from the central portion 2a to the peripheral portion 2b, a voltage is applied between the electrodes 4a and 4b by the power supply 11. When this voltage is applied, an electric field is generated between the electrodes 4a and 4b, and the viscosity of the electrorheological fluid 10 in the surrounding portion 2b sandwiched between the electrodes 4a and 4b increases. ), Natural convection becomes difficult, as a result, as shown in equation (6), the heat transfer between the electrorheological fluid 10 in the surrounding portion 2b and the heat storage tank 2 is reduced, and therefore External heat loss is also reduced. The amount of heat supplied to the heat storage device from the outside is
When the amount of heat is larger than the amount of heat diffused from a to the surrounding portion 2b, no voltage is applied between the electrodes 4a and 4b,
It is also possible to make the heat storage tank 2 efficiently absorb heat injected from the outside by reducing the viscosity of the peripheral portion 2b and allowing heat to freely move from the central portion 2a to the peripheral portion 2b.

In the process of storing heat, a voltage is applied to the electrodes 4a and 4b by the power supply 11. By applying the voltage, the heat loss from the heat storage device to the outside is reduced for the above-described reason.
In the heat extraction process, the heat storage tank 2 is passed through the heat exchanger 3.
, Heat corresponding to the temperature of the electrorheological fluid 10 can be extracted. When the temperature of the electrorheological fluid 10 in the central portion 2a decreases with the extraction of heat, the temperature difference between the central portion 2a and the peripheral portion 2b increases, so that the peripheral portion 2a
b moves toward the central portion 2a,
The electrorheological fluid 10 in b is gradually cooled.

If the amount of heat required for the heat storage device from the outside is sufficient with the heat stored in the central portion 2a, the power supply 11
A voltage is applied between the electrodes 4a and 4b. By applying the voltage, the heat loss from the heat storage device to the outside is reduced for the above-described reason. If the amount of heat required for the heat storage device from the outside is insufficient with only the heat stored in the central portion 2a,
By not applying a voltage between the electrodes 4a and 4b, the viscosity of the peripheral portion 2b is reduced, and heat is freely transferred from the peripheral portion 2b to the central portion 2a, so that heat required outside can be efficiently removed. Extraction from the heat storage tank 2 is also possible. In the case of storing heat at a temperature lower than the environment outside the heat storage device, the basic operation is the same as described above, except that the direction of heat flow is opposite to the temperature. Also,
By covering the outer surface of the heat storage tank 2 with the heat insulating layer 9 as in the fourth embodiment, a heat storage device with lower heat loss can be provided.

Embodiment 6 FIG. 6 is a sectional view of another embodiment of the heat storage device according to the present invention. This heat storage device is shown in FIG.
A heat storage tank 2 and a heat exchanger 3 similar to those of the embodiment are provided, but a magnetic fluid 1 serving as a heat storage material is provided in the heat storage tank 2.
2 is filled. This magnetic fluid has a property of increasing the viscosity when a magnetic field is applied. A boundary between the central portion 2a and the peripheral portion 2b in the heat storage tank 2,
A large number of electromagnets 13 a, 1 that generate a magnetic force by applying a voltage from an external power source 11 are provided outside the heat storage tank 2.
3b is provided. Their number can be set arbitrarily. In the figure, the electromagnets 13a and 13b and the power supply 1
The wiring between them is omitted.

The electromagnet 13a is provided such that the magnetic poles face away from the center portion 2a, and the electromagnet 13b is provided such that the magnetic poles face away from the outside of the heat storage device. The materials and structures of the electromagnets 13a and 13b are not limited as long as a magnetic field can be generated only in the surrounding portion 2b. For example, permanent magnets can be used instead of the electromagnets 13a and 13b, and the basic function is not changed in such a case. The magnetic fluid 12 includes the heat storage tank 2, the heat exchanger 3, the electromagnet 1
The material and composition are not limited as long as they are stable with respect to 3a and 13b. For example, various substances can be used depending on the required heat storage temperature, such as a liquid in which ferrite powder is suspended.

Next, the operation of the heat storage device shown in FIG. 6 when storing a higher temperature than the environment outside the heat storage device will be described. In the heat injection process, the central portion 2 of the magnetic fluid 12 filled in the heat storage tank 2 using the heat exchanger 3 is used.
The material in a is heated to increase the temperature. Center part 2
a when the temperature of the magnetic fluid 12 in the center part 2 rises.
Since the temperature difference between a and the peripheral portion 2b increases, heat moves from the central portion 2a toward the peripheral portion 2b, and the magnetic fluid 12 in the peripheral portion 2b is gradually heated.

When the amount of heat supplied from the outside to the heat storage device is equal to or less than the amount of heat diffused from the central portion 2a to the peripheral portion 2b, the power supply 11 supplies electricity to the electromagnets 13a and 13b. Due to this energization, the electromagnets 13a and 13b are arranged so that the magnetic poles are directed toward the peripheral portion 2b, so that the magnetic field does not act on the central portion 2a where the magnetic poles face backward, and are sandwiched between the electromagnets 13a and 13b. A magnetic field is generated in the surrounding portion 2b. Therefore, the magnetic fluid 12 in the central portion 2a
Is not affected by the magnetic field, but the magnetic fluid 12 in the surrounding portion 2b is affected by the magnetic field, and the apparent viscosity increases. Due to the increase in viscosity, the equation (4)
As a result, natural convection becomes difficult, and as a result, as shown in the equation (6), heat transfer between the magnetic fluid 12 in the surrounding portion 2b and the heat storage tank 2 is reduced, and Heat loss is also reduced.

When the amount of heat supplied to the heat storage device from the outside is larger than the amount of heat diffused from the central portion 2a to the peripheral portion 2b, the energization of the electromagnets 13a and 13b is stopped to reduce the viscosity of the peripheral portion 2b. Make it smaller, center part 2a
It is also possible to make the heat storage tank 2 efficiently absorb the heat injected from the outside by allowing the heat to freely move from the air to the surrounding portion 2b.

In the process of storing heat, the power supply 11
By energizing 3a and 13b, heat loss from the heat storage device to the outside can be reduced for the above-described reason. In the heat extraction process, heat corresponding to the temperature of the magnetic fluid 12 can be extracted from the heat storage tank 2 by the heat exchanger 3. When the temperature of the magnetic fluid 12 in the central portion 2a decreases with the extraction of heat, the central portion 2a and the peripheral portion 2b
Since the temperature difference between the peripheral portion 2b and the central portion 2a increases, the magnetic fluid 12 in the peripheral portion 2b is gradually cooled. When the amount of heat required for the heat storage device from the outside is sufficient with the heat stored in the central portion 2a, the power supply 11 supplies power to the electromagnets 13a and 13b, and the power supply supplies the electromagnets 13a and 13b to the heat storage device for the same reason as described above. Heat loss is reduced. If the amount of heat required for the heat storage device from the outside is insufficient with only the heat stored in the central portion 2a, the energization of the electromagnets 13a and 13b is stopped to reduce the viscosity of the peripheral portion 2b and reduce the viscosity of the peripheral portion 2b. The heat transfer from the heat storage tank 2 to the central portion 2a can be freely performed, and the heat required outside can be efficiently extracted from the heat storage tank 2.

The operation when the electromagnets 13a and 13b are replaced by permanent magnets is the same as when the electromagnets 13a and 13b are energized. In the case of storing heat at a temperature lower than the environment outside the heat storage device, the basic operation is the same as described above, except that the direction of heat flow is opposite to the temperature. Further, by covering the outer surface of the heat storage tank 2 with the heat insulating layer 9 as in the fourth embodiment, a heat storage device with smaller heat loss can be provided.

[Embodiment 7] FIG. 7 is a sectional view of another embodiment of the heat storage device according to the present invention. This heat storage device is shown in FIG.
As in the embodiment of the present invention, the heat storage material 1 for storing heat is stored in the heat storage tank 2 and the heat storage tank 2 is provided with a heat exchanger 3 for performing heat exchange with the outside. A large number of barriers 14 are provided in a peripheral portion 2 b partitioned by the net 4. The material and structure of the barrier 14 are not limited as long as it is stable with respect to the heat storage material 1 and prevents the heat storage material 1 from moving straight. For example, a net-like material can be used. In this embodiment, the liquid absorbing material 5 used in the embodiment of FIG. 1 is not used, but it can be used. Other configurations are the same as those in the embodiment shown in FIG. 1, and thus description thereof is omitted.

Next, the operation of the heat storage device shown in FIG. 7 when storing a temperature higher than the environment outside the heat storage device will be described. The operation in the heat injection process is basically the same as in the first embodiment. In the heat preservation process, heat is transferred from the central portion 2a to the external environment surrounding the heat storage tank 2 through the peripheral portion 2b and the heat storage tank 2, so that the temperature of the heat storage material 1 gradually decreases. However, there is a finely intricate barrier 14 in the peripheral part 2b, and even if the heat storage material 1 in the peripheral part 2b tries to move to the center part 2a side, it cannot keep going straight, and the collision is repeated at the barrier 14. . Thereby, the moving speed of the heat storage material 1 becomes smaller than the case where the barrier 14 is not provided, and apparently the heat storage material 1 in the surrounding portion 2b is provided.
Has the same effect as increasing the viscosity ν of
As a result, natural convection becomes difficult, and as a result, as shown in equation (6), heat transfer between the heat storage material 1 and the heat storage tank 2 in the surrounding portion 2b decreases, and Heat loss is also reduced.

The operation of the heat extraction process is basically the same as that of the first embodiment.
Is the same as In the case of storing heat at a temperature lower than the environment outside the heat storage device, the basic operation is the same as described above, except that the direction of heat flow is opposite to the temperature. Further, as in Embodiment 4, the outer surface of the heat storage tank 2 is
, It is also possible to make a heat storage device with smaller heat loss.

[Embodiment 8] FIG. 8 is a sectional view of another embodiment of the heat storage device according to the present invention. This heat storage device is shown in FIG.
In the same manner as in the embodiment, the heat storage material 1 for storing heat is stored in the heat storage tank 2, and the heat storage tank 2 is provided with a heat exchanger 3 for exchanging heat with the outside. Further, in the heat storage material 1, the polymer liquid-absorbing substance 5 is dispersed in a peripheral portion 2 b defined by the net 4 in the heat storage tank 2. A heat transfer element 15 capable of arbitrarily promoting the transfer of heat is provided between the central portion 2a and the peripheral portion 2b in the heat storage tank. The material, structure, mechanism, and the like of the heat transfer element 15 are not limited as long as the heat transfer element 15 is stable with respect to the heat storage material 1. For example, even if a thermoelectric element is capable of transporting an arbitrary amount of heat in an arbitrary direction by applying an external voltage, the heat transfer resistance changes significantly with temperature, as in a heat pipe. You may do.

Next, the operation of the heat storage device shown in FIG. 8 when storing a temperature higher than the environment outside the heat storage device will be described. The operation in the heat injection process is basically the same as in the first embodiment. However, if the amount of heat supplied from the outside to the heat storage device is too much to heat the heat storage material 1 in the central portion 2a, in addition to the procedure of the first embodiment, the heat transfer element 15 causes the heat transfer element 15 to move from the central portion 2a to the peripheral portion. By promoting the heat transfer to the central portion 2b and transferring the excess heat in the central portion 2a to the peripheral portion 2b, the heat supplied from the outside can be stored in the thermal storage device as quickly as possible with no excess. .
The operation in the process of storing heat is also the same as in the first embodiment, and the heat loss from the heat storage device is smaller than in the conventional example. The operation of the heat extraction process is basically the same as in the first embodiment. However, the amount of heat required from the outside to the heat storage device depends on the central part 2
In the case where it is not enough to simply use the heat stored in the heat storage material 1 in FIG.
Promotes the heat transfer from the peripheral portion 2b to the central portion 2a, and transfers the heat that is insufficient in the central portion 2a from the peripheral portion 2b, so that the heat required from the outside can be quickly removed from the heat storage device as short as possible. Can be extracted. In the case of storing heat at a temperature lower than the environment outside the heat storage device, the basic operation is the same as described above, except that the direction of heat flow is opposite to the temperature. Further, in the present embodiment, the case where the heat storage tank and the like are the same as in the first embodiment is shown, but the same operation can be obtained also in the case where the structure is as described in the second to seventh embodiments. .

[Embodiment 9] FIG. 9 is a sectional view of another embodiment of the heat storage device according to the present invention. This heat storage device is shown in FIG.
As in the embodiment, the heat storage material 1 for storing heat is stored in the heat storage tank 2, and the heat storage tank 2 is provided with a heat exchanger 16 for exchanging heat with the outside. In the heat storage material 1, the polymer liquid-absorbing substance 5 is dispersed in a peripheral portion 2 b partitioned by the net 4 in the heat storage tank 2. The heat exchanger 16 has a central portion 2a.
And the surrounding portion 2b are sequentially arranged, and the structure such as the material, the cross-sectional shape, and the presence or absence of the fin is not limited as long as the material has stability with respect to the heat storage material 1.

Next, the operation of each step in the case of storing a higher temperature than the environment outside the heat storage device in the heat storage device of FIG. 9 will be described. The operation in each process is basically the same as in the first embodiment. In the heat injection process, first, the heat exchanger 16 is used to heat the material in the central portion 2a of the heat storage material 1 filled in the heat storage tank 2 to increase the temperature.
Next, the heat storage material 1 in the surrounding portion 2b is heated by the residual heat. In the first embodiment, the heat storage material 1 in the peripheral portion 2b is gradually heated by the heat transfer due to the temperature rise of the heat storage material 1 in the central portion 2a, but the peripheral portion 2b is apparent as described in the first embodiment. Is so viscous that heat transfer is difficult,
By using the heat exchanger 16, heat can be injected more quickly than in the first embodiment.

In the heat preservation process, as in the first embodiment, since the apparent viscosity of the heat storage material 1 in the surrounding portion 2b is large, the heat transfer between the heat storage material 1 in the surrounding portion 2b and the heat storage tank 2 is performed. And therefore the heat loss to the outside is also reduced. In the heat extraction process, the heat exchanger 16 first heats the heat medium that exchanges heat with the outside with the heat in the surrounding part 2b of the heat storage material 1 filled in the heat storage tank 2, and heats the heat medium. Preheat. Next, the heat medium is heated by the heat of the heat storage material 1 in the central portion 2a. In the first embodiment, the heat storage material 1 in the peripheral portion 2b is gradually cooled by heat transfer due to a temperature drop of the heat storage material 1 in the central portion 2a. Also in this embodiment, the peripheral portion 2b has a large apparent viscosity and is difficult to transfer heat.
It becomes possible to cause heat extraction to be performed more quickly. In the case of storing heat at a temperature lower than the environment outside the heat storage device, the basic operation is the same as described above, except that the direction of heat flow is opposite to the temperature. Further, in this embodiment, the case where the heat storage tank and the like are the same as in the first embodiment is shown. However, the same operation can be obtained by applying to the structures described in the second to eighth embodiments. It is.

[Embodiment 10] FIG. 10 is a sectional view of another embodiment of the heat storage device according to the present invention. This heat storage device
Instead of the heat exchanger 16 in the embodiment of FIG.
The heat exchangers 17a and 17b that can separately heat or cool the central portion 2a and the peripheral portion 2b are provided. As long as the heat exchangers 17a and 17b are stable with respect to the heat storage material 1, the structure such as the material, the cross-sectional shape, and the presence or absence of the fin is not limited. Note that other configurations are the same as those in the embodiment of FIG. 9, and thus description thereof will be omitted.

Next, the operation of the heat storage device shown in FIG. 10 when the temperature is higher than the environment outside the heat storage device will be described. The operation in each process is basically the same as in the first embodiment. In the heat injection process, the procedure is different in the following three cases. The first procedure is adopted when the temperature of the heat source from the outside is higher than the temperature of the heat storage material 1 in the central portion 2a, and there is a sufficient amount of heat to heat the central portion 2a. At this time, the heat medium for exchanging heat with the outside is first supplied from the heat source to the heat exchanger 17a.
And heats the heat storage material 1 in the central portion 2a and returns the same to the outside.
b is higher than the temperature of the heat storage material 1 in the surrounding portion 2b, the heat medium is then sent to the heat exchanger 17b.
Is heated and then returned to the heat source. By sending the heat medium returned from the heat exchanger 17a to the heat exchanger 17b, the heat storage material 1 in the surrounding portion 2b can be quickly heated, and the efficiency of heat exchange in the heat source can be improved. become. This is because the temperature of the heat medium sent from the heat source decreases and is sent back to the heat source as compared with the case where only the heat storage material 1 in the central portion 2a is heated, so that the heat exchange temperature difference in the heat source increases.

The second procedure in the heat injection process is performed when the temperature of the heat source from the outside is higher than the temperature of the heat storage material 1 in the central portion 2a, but the amount of heat is sufficient to heat the central portion 2a. Can be At this time, the heat medium from the heat source is sent to the heat exchanger 17a, heats the heat storage material 1 in the central portion 2a, and is returned to the heat source again. Although the temperature of the heat medium returned from the heat exchanger 17a is higher than the temperature of the heat storage material 1 in the surrounding portion 2b, the heat medium cannot be further sent to the heat exchanger 17b as in the first procedure. Because, in this case, the heat amount of the heat source is not sufficient, the heat medium whose temperature has been further reduced by using the heat exchanger 17b is again heated to a higher temperature than the heat storage material 1 in the central portion 2a by the heat source. The heat exchanger 17a and the heat exchanger 1 cannot be
This is because the circulation returning to the heat source via 7b is not thermally established.

The third procedure in the heat injection process is performed when the temperature of the external heat source is lower than the temperature of the heat storage material 1 in the central portion 2a and higher than the temperature of the heat storage material 1 in the peripheral portion 2b. Can be In this case, when the heat medium from the heat source is sent to the heat exchanger 17a, the temperature of the heat storage material 1 in the central portion 2a is lowered.
7b to heat the heat storage material 1 in the surrounding portion 2b,
It is returned to the heat source again. Since the temperature of the surrounding portion 2b is between the temperature of the central portion 2a and the temperature of the environment outside the heat storage device, the use of the heat exchanger 17b alone enables the heat source 17b to operate even if the temperature of the heat source is not sufficiently high. In addition, the energy of the heat source can be effectively stored in the heat storage device. In the heat preservation process, as in the first embodiment, since the apparent viscosity of the heat storage material 1 in the surrounding portion 2b is large, the heat transfer between the heat storage material 1 in the surrounding portion 2b and the heat storage tank 2 is reduced. Therefore, heat loss to the outside is also reduced.

In the process of extracting heat, the procedure is different in the following three cases. The first procedure is adopted when the temperature of heat required outside is close to the temperature of the heat storage material 1 in the central portion 2a and the heat of the central portion 2a alone is insufficient. At this time,
The heat medium for exchanging heat with the outside is first sent from the heat source to the heat exchanger 17b, is preheated by the heat storage material 1 in the surrounding portion 2b, and is once returned to the outside. Since the temperature of the heat medium returned from the heat exchanger 17b is lower than the temperature of the heat storage material 1 at the central portion 2a, the heat medium is then sent to the heat exchanger 17a, where the heat medium is transferred to the heat storage material 1 at the central portion 2a. It is heated and then returned to the outside. Before heating the heat medium with the heat exchanger 17a,
By preheating the heat medium in the heat exchanger 17b, the heat of the heat storage material 1 in the surrounding portion 2b can be quickly extracted, and the central portion 2 due to a large external load can be extracted.
Also, it is possible to suppress a rapid temperature drop of a.

The second procedure in the heat extraction process is adopted when the temperature of the heat required outside is close to the temperature of the heat storage material 1 in the central portion 2a and the amount extracted from the central portion 2a is sufficient. . At this time, the heat medium from the outside is the heat exchanger 1
It is sent to 7a, heated by the heat storage material 1 in the central portion 2a, and returned to the outside again for use.

The third procedure in the process of extracting heat is that the temperature of the heat required outside is lower than the temperature of the heat storage material 1 in the central portion 2a but higher than the temperature of the heat storage material 1 in the peripheral portion 2b. Taken. In this case, the heat medium from the outside is heated by the heat exchanger 17b and returned to the outside for use. If the heat medium from the outside is sent to the heat exchanger 17a, even if the amount of heat extracted from the heat storage device to the outside is the same, the central portion 2 at a higher temperature than the surrounding portion 2b.
This is not good because the temperature of the heat storage material 1 of a is lowered and the effective energy (exergy) of the heat storage device is further reduced.

For example, the average temperature of the heat storage material 1 in the central portion 2a is 60 ° C., and the heat storage material 1 in the peripheral portion 2b is
Is 50 ° C., the temperature of the external heat carrier is 30 ° C., and the required heat temperature is 40 ° C. Further, by using the heat exchanger 17b, the heat medium of 30 ° C. is heated by the heat of the heat storage material 1 in the surrounding portion 2b, and
When the temperature is set to 0 ° C., the average temperature of the surrounding portion 2b is assumed to be 42 ° C. Similarly, using the heat exchanger 17a, the heat medium of 30 ° C. is heated by the heat of the heat storage material 1 in the central portion 2a to 40 ° C.
In this case, it is assumed that the average temperature of the central portion 2a becomes 56 ° C. In this case, it seems at first glance that the use of the heat exchanger 17a is more effective because the decrease in temperature is small, but, for example, when the next heat of 58 ° C. is required, the former uses the heat storage material 1 Although the temperature of the peripheral portion 2b has dropped to 42 ° C., the temperature of the central portion remains at 60 ° C. Therefore, this time, the heat medium of the heat storage material 1 in the central portion 2a is heated using the heat exchanger 17a. Can be heated to extract 58 ° C. heat. On the other hand, in the latter, the temperature of the heat storage material 1 in the surrounding portion 2b remains at 50 ° C., but the temperature of the central portion 2a has dropped to 56 ° C., so that it is impossible to extract the heat of 58 ° C. It is. That is, the effectiveness of the heat storage device is reduced.

As described above, the third procedure is to reduce the effectiveness of the heat storage device as much as possible by extracting heat from an appropriate portion of the heat storage material 1 corresponding to the temperature of heat required from the outside. It is to prevent it from being done. This makes it possible to provide a heat storage device that operates efficiently with respect to a wide fluctuation range of the heat supply amount and the demand amount. In the case of storing heat at a temperature lower than the environment outside the heat storage device, the basic operation is the same as described above, except that the direction of heat flow is opposite to the temperature. Further, in the present embodiment, the case where the heat storage tank and the like are the same as in the first embodiment is shown.
The same operation can be obtained for the structure described in (1).

[0081]

According to the heat storage device of the present invention described above, the convection of the heat storage material or the heat medium that is movable inside the heat storage tank is partially different, so that heat from the outside to the heat storage material can be obtained. Injection and extraction operations are performed in the central area where convection is likely to occur, and heat storage is mainly performed in the surrounding area where convection does not easily occur, so not only in the heat preservation process but also in the heat injection / extraction process Also, natural convection generated inside the heat storage material due to a temperature difference generated by heat exchange with the outside occurs in the central portion of the heat storage tank and hardly occurs in the surrounding portion. The heat transmission coefficient k becomes smaller than before. Therefore, it is possible to provide a heat storage device having a small heat loss from the heat storage material to the outside.

Further, a mechanism for forming an electric field or a magnetic field is provided, and a fluid whose viscosity increases or decreases depending on the intensity of the electric field or the magnetic field is used as a heat storage material, so that a convection state in the heat storage tank can be controlled. It is possible to provide a heat storage device having a small heat loss as described above while efficiently operating the heat storage tank according to the above. Further, by providing the heat transfer element in the central portion and the peripheral portion, the heat transfer between the peripheral portion and the central portion having basically small heat transfer can be temporarily promoted as necessary, so that the heat It is possible to provide a heat storage device with a small heat loss as described above, while efficiently operating the heat storage tank according to the demand and supply of the heat.

Further, by arranging the heat exchanger so as to go around the central portion and the peripheral portion of the heat storage tank, it is possible to directly perform heat exchange with the peripheral portion where heat transfer is basically small. In addition, since heat can be injected or extracted into the central portion and the peripheral portion in sequence, heat exchange between the heat storage device and the outside can be performed quickly and in large quantities, and heat loss to the outside can be reduced as described above. It is possible to provide a small heat storage device. By separately arranging the heat exchangers in the central portion and the peripheral portion of the heat storage tank, respectively, the central portion and the peripheral portion at different temperatures, or both can be selectively used. As described above, it is possible to provide a heat storage device with small heat loss to the outside while efficiently exchanging heat with the outside according to the demand and supply of heat.

[Brief description of the drawings]

FIG. 1 is a sectional view of one embodiment of a heat storage device according to the present invention.

FIG. 2 is a sectional view of another embodiment of the heat storage device according to the present invention.

FIG. 3 is a sectional view of another embodiment of the heat storage device according to the present invention.

FIG. 4 is a sectional view of another embodiment of the heat storage device according to the present invention.

FIG. 5 is a sectional view of another embodiment of the heat storage device according to the present invention.

FIG. 6 is a sectional view of another embodiment of the heat storage device according to the present invention.

FIG. 7 is a sectional view of another embodiment of the heat storage device according to the present invention.

FIG. 8 is a sectional view of another embodiment of the heat storage device according to the present invention.

FIG. 9 is a sectional view of another embodiment of the heat storage device according to the present invention.

FIG. 10 is a sectional view of another embodiment of the heat storage device according to the present invention.

FIG. 11 is a cross-sectional view showing an example of a conventional heat storage device.

FIG. 12 is a cross-sectional view showing another example of the conventional heat storage device.

FIG. 13 is a cross-sectional view showing another example of the conventional heat storage device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a, 1b Heat storage material 2 Heat storage tank 2a Central part 2b Peripheral part 3 Heat exchanger 4a, 4b Electrode 4 Net 5 Polymer liquid-absorbing substance 6a, 6b Communication pipe 7a, 7b Small container 8 Heat medium 9 Heat insulation layer 10 Electrorheological fluid 11 Power supply 12 Magnetic fluid 13a, 13b Electromagnet 14 Barrier 15 Heat transfer element 16, 17a, 17b Heat exchanger

Claims (9)

(57) [Claims] 1. A heat storage tank filled with a heat storage material for storing heat given from outside, and heat is injected / extracted between the inside and outside of the heat storage tank by heat exchange between the heat storage material and a heat medium. Heat exchange means, wherein the heat exchange means is disposed so as to perform heat exchange between a central portion of the heat storage tank and the outside, and suppresses natural convection of the heat storage material in a peripheral portion of the heat storage tank. A heat storage device comprising means. 2. A heat storage tank filled with a heat storage material for storing heat given from the outside, and heat is injected and extracted between the inside and outside of the heat storage tank by heat exchange between the heat storage material and a heat medium. A heat exchange means, wherein the heat exchange means is arranged so as to sequentially perform heat exchange with the outside with respect to a central portion and a peripheral portion of the heat storage tank, and a heat storage material is provided in a peripheral portion of the heat storage tank. A heat storage device comprising a suppression means for suppressing natural convection. 3. A heat storage tank filled with a heat storage material for storing heat given from outside, and heat is injected and extracted between the inside and outside of the heat storage tank by heat exchange between the heat storage material and a heat medium. A heat exchange means, wherein the heat exchange means is disposed so as to individually perform heat exchange with the outside with respect to a central portion and a peripheral portion of the heat storage tank, and a heat storage material is provided in a peripheral portion of the heat storage tank. A heat storage device, comprising: means for suppressing natural convection. 4. A heat storage tank filled with a heat medium also serving as a heat storage material for storing heat given from the outside, and heat inflow / injection between the inside and outside of the heat storage tank by flowing in and out of the heat medium. Heat transport means for performing extraction, the heat transport means is arranged to perform heat transport between the central portion of the heat storage tank and the outside,
A heat storage device, comprising: a means for suppressing natural convection of a heat medium around a heat storage tank. 5. The heat storage device according to claim 1, wherein the suppressing means is configured by dispersing a liquid absorbing material in a heat storage material or a heat medium in a peripheral portion of the heat storage tank. Characteristic heat storage device. 6. The heat storage device according to claim 1, wherein the heat storage material or the heat medium around the heat storage tank has a property of increasing viscosity by applying a voltage, as the suppression means. A heat storage device, comprising: electrodes arranged so as to sandwich a peripheral portion of a heat storage tank, and means for supplying electricity between the electrodes. 7. The heat storage device according to claim 1, wherein the heat storage material or the heat medium in the peripheral portion of the heat storage tank has a property of increasing viscosity by a magnetic force, and the heat storage tank as a suppressing means. A heat storage device characterized in that a magnet for applying a magnetic force is provided on a peripheral portion of the heat storage device. 8. The heat storage device according to claim 1, wherein a barrier for preventing natural convection of the heat storage material or the heat medium is provided as a suppressing means in a peripheral portion of the heat storage tank. apparatus. 9. The heat storage device according to claim 1, wherein the heat storage tank is provided between a central portion and a peripheral portion in the heat storage tank.
A heat storage device comprising means for promoting heat transfer.