JP2695615B2 - Heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exothermic reaction when hydrogen is absorbed by a hydrogen-storing metal material and the hydrogen-storing metal material is converted into a metal hydride. The present invention relates to a heat exchanger that performs heat exchange by utilizing an endothermic reaction when returning to a hydrogen storage metal material, in which the hydrogen storage metal material is accommodated in a pressure vessel, and hydrogen is supplied into the pressure vessel by hydrogen supply / discharge means. And a heat exchanger for discharging hydrogen from the inside of the pressure vessel.

[0002]

2. Description of the Related Art In recent years, the destruction of the ozone layer due to Freon gas or the like has become a problem, and the use of compressor type heat exchangers using Freon gas or the like has been gradually restricted from the standpoint of global environmental protection. Therefore, in recent years, various types of heat exchangers different from those described above have been developed.

[0003] As one of such heat exchangers, an exothermic reaction occurs when hydrogen is absorbed by a hydrogen storage metal material and the hydrogen storage metal material becomes a metal hydride, and hydrogen is released from the metal hydride. A heat exchanger containing a hydrogen storage metal material has been developed in which heat exchange is performed by utilizing an endothermic reaction when the metal hydride returns to the hydrogen storage metal material.

[0004] Further, in order to perform sufficient heat exchange in such a heat exchanger, various studies have been made on a hydrogen storage metal material to be used. Here, such a hydrogen storage metal material should have an appropriate equilibrium hydrogen pressure in accordance with the operating temperature level, have a small inclination and hysteresis in the plateau region, have excellent reversibility, and have an effective hydrogen absorption amount. It is preferable to use a hydrogen storage alloy containing a rare earth element as a hydrogen storage metal material having such characteristics as being large, having a high reaction rate, and having an excellent cycle life of hydrogen absorption and desorption. Was developed.

Conventionally, as a heat exchanger using the above-described hydrogen storage metal material, as shown in FIG. 1, a powder of the hydrogen storage metal material M is stored in a pressure vessel 10, The pressure vessel 10 is supplied by the supply / discharge means 20.
The hydrogen storage metal material M absorbs hydrogen to form a metal hydride MH by supplying hydrogen into the pressure vessel 10 or releasing hydrogen from the pressure vessel 10, or generates a hydrogen hydride from the metal hydride MH. The pressure vessel 10 itself is heated or cooled by utilizing an endothermic reaction when hydrogen is released and returns to the hydrogen storage metal material M. As shown in FIG. There is a medium pipe 30 through which a heat exchange medium for performing heat exchange with the hydrogen storage metal material M is provided, and the medium for heat exchange flowing in the medium pipe 30 is heated or cooled. .

Here, as described above, the hydrogen storage metal material M
When hydrogen is absorbed into the metal hydride, the volume expands. On the other hand, when the hydrogen is released from the metal hydride MH that has absorbed the hydrogen, the volume contracts. When releasing, the hydrogen storage metal material M
The hydrogen-absorbing metal material M thus pulverized was biased toward the bottom of the pressure vessel 1, and the density of the hydrogen-absorbing metal material M at the bottom of the pressure vessel 1 was gradually increased.

For this reason, in the above-described heat exchanger, when hydrogen is repeatedly absorbed and released from the hydrogen storage metal material M, the hydrogen storage metal material M absorbs the hydrogen and the metal hydrogen is absorbed. The volume expansion at the time of becoming the compound MH becomes large at the bottom of the pressure vessel 1 in which the density of the hydrogen storage metal material M is increased, the internal stress at the bottom of the pressure vessel 1 increases, and the bottom of the pressure vessel 1 gradually increases. Deformed,
In an extreme case, there is a problem that the pressure vessel 1 is broken.

In order to prevent the pressure vessel 10 from changing as described above, it has been considered that the filling rate of the hydrogen storage metal material M to be filled in the pressure vessel 10 is reduced. If the filling rate of the resin is low, there is a problem that efficient and sufficient heat exchange cannot be performed.

Further, as described above, the hydrogen storage metal material M
Is stored in the pressure vessel 10 as it is to generate or absorb heat, the pressure vessel 10 itself is heated or cooled,
As shown in the heat exchanger shown in FIG. 2, a medium pipe 30 for passing a heat exchange medium is provided in the pressure vessel 10, and the heat exchange medium flowing in the medium pipe 30 is heated or heated by a hydrogen storage metal material M. In the case of cooling, the heat is transmitted to the pressure vessel 1 and lost, and the pressure vessel 1 is switched every time the hydrogen absorbing metal material M in the pressure vessel 1 switches between heat absorption and heat generation.
There is also a problem that heat loss due to sensible heat of 0 also occurs, and heat exchange efficiency is deteriorated.

[0010]

According to the present invention, a hydrogen storage metal material is accommodated in a pressure vessel, hydrogen is supplied into the pressure vessel through a hydrogen supply / discharge means, and the hydrogen is absorbed by the hydrogen storage metal material. Heat exchange using the exothermic reaction when converting to metal hydride by heat and the endothermic reaction when releasing hydrogen from the supplied metal hydride and returning it to the hydrogen storage metal material It is an object of the present invention to solve the above-mentioned problems in a vessel.

That is, according to the present invention, in the above-described heat exchanger, the operation of absorbing and releasing hydrogen in the hydrogen-absorbing metal material is repeated many times. Even in the case of pulverization, the pressure vessel does not deform due to volume expansion when the hydrogen storage metal material absorbs hydrogen to become metal hydride, so that the heat exchanger can be used stably for a long time. In addition, the pressure vessel is sufficiently filled with the hydrogen storage metal material so that efficient heat exchange can be performed,
Further, a medium pipe for passing a heat exchange medium is provided in the pressure vessel,
It is an object of the present invention to reduce the heat loss in a pressure vessel and perform efficient heat exchange when heating or cooling a heat exchange medium flowing in the medium pipe with a hydrogen storage metal material. .

[0012]

According to the present invention, in order to solve the above-mentioned problems, a pressure vessel containing a hydrogen storage metal material, a method for supplying hydrogen into the pressure vessel, and a method for supplying hydrogen to the pressure vessel. In a heat exchanger having a hydrogen supply / discharge means for discharging hydrogen from a hydrogen storage metal material, the hydrogen storage metal material is accommodated in an upper side of the pressure vessel, and a buffer section is provided in a lower side of the pressure vessel. is there.

Here, when the hydrogen storage metal material is accommodated in the upper part of the pressure vessel and the buffer is provided in the lower part of the pressure vessel as described above, the buffer may be a space, In order to further reduce the heat loss due to the sensible heat of the pressure vessel in this heat exchanger and increase the heat exchange efficiency, it is preferable to provide a cushioning heat insulating material having high cushioning and heat insulating properties in this buffer portion.

[0014]

In the heat exchanger according to the present invention, the hydrogen storage metal material is accommodated in the upper portion of the pressure vessel as described above, and the buffer portion is provided in the lower portion of the pressure vessel. When the metal material absorbs hydrogen and becomes a metal hydride, even if its volume expands, this volume expansion is absorbed by the buffer provided on the lower side of the pressure vessel and acts on the pressure vessel. And the pressure vessel is not deformed or destroyed.

Further, since the pressure vessel is not deformed by the volume expansion of the hydrogen storage metal material as described above, the filling rate of the hydrogen storage metal material can be increased on the upper side in the pressure vessel, which is efficient. Heat exchange can be performed.

Further, in the heat exchanger of the present invention, since the buffer is provided on the lower side of the pressure vessel as described above, the heat of the hydrogen storage metal material is transmitted to the pressure vessel through the buffer. At least, a medium pipe for passing a heat exchange medium is provided in the pressure vessel as described above, and when the heat exchange medium flowing in the medium pipe is heated or cooled by a hydrogen absorbing metal material, the heat passing through the pressure vessel is reduced. The loss is reduced, and the heat loss due to the sensible heat is also reduced.

Further, in the heat exchanger of the present invention, since the buffer portion is provided only on the lower side in the pressure vessel which is likely to be deformed when the hydrogen storage metal material absorbs hydrogen and expands in volume, the pressure is reduced. The container never gets too large.

Further, as described above, when a cushioning heat insulating material having a high cushioning property is provided in the buffering portion on the lower side in the pressure vessel, the deformation of the pressure vessel is suppressed by the buffering heat insulating material, and the buffering portion is formed. The heat transmitted to the pressure vessel through the pressure vessel is also reduced, and the heat loss in the pressure vessel is further suppressed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A heat exchanger according to an embodiment of the present invention will be specifically described below with reference to the accompanying drawings.

In the heat exchanger in this embodiment,
As shown in FIG. 3, as a pressure vessel 10, a vessel body 11 having a cylindrical shape provided with a flange 11 a at one open end and having the other end closed is provided.
1 and a lid 12 for closing the opened end, and the lid 12 is attached to the flange 11a of the opened end of the container body 11 with bolts, nuts (not shown) or the like. The pressure vessel 10 was hermetically sealed.

Here, when the hydrogen storage metal material M is accommodated in the pressure vessel 10, in the heat exchanger of this embodiment, as shown in FIGS.
A large number of disc-shaped heat exchange fins 13 are arranged along the axial direction within 0, and around the heat exchange fins 13 provided along the axial direction of the pressure vessel 10 as described above. The holding member 14 made of an aluminum sheet or the like is provided.

Then, in a state where the holding members 14 are arranged around the heat exchange fins 13 provided in large numbers as described above, the powdery hydrogen-absorbing metal material M is put into each heat exchange fin 1.
3 and filled in the upper part of the pressure vessel 10,
A buffer portion 15 which is a space is formed at a lower portion thereof, and as shown in FIG. 5, the buffer portion 15 has a cushioning and heat insulating property and a ceramic fiber type buffer heat insulating material having excellent heat resistance. No. 16 was charged.

In the heat exchanger of this embodiment,
In providing the hydrogen supply / discharge means 20 for supplying hydrogen into the pressure vessel 10 or discharging hydrogen from the pressure vessel 10, the hydrogen supply / discharge pipe 21 is connected to the pressure vessel 10 through the lid 12 of the pressure vessel 10. Lead into 10,
In the pressure vessel 10, the hydrogen supply / discharge pipe 21
Is branched into a plurality of filter-type hydrogen ventilation pipes 22, and the branched filter-type hydrogen ventilation pipes 22 are arranged in the pressure vessel 10 through the heat exchange fins 13. In addition, as this filter type hydrogen ventilation pipe 22,
The periphery thereof was formed in a very fine mesh shape and used to allow passage of hydrogen but not passage of the powder of the hydrogen storage metal material M.

Further, in this embodiment, a medium pipe 30 is passed through the lid 12 of the pressure vessel 10 to allow a heat exchange medium for performing heat exchange with the hydrogen storage metal material M to pass through the pressure vessel 10. Is introduced into the pressure vessel 10, and the medium tube 30 is arranged so as to be folded many times in the pressure vessel 10 through the heat exchange fins 13, and then the pressure vessel 10 is passed through the lid 12. Derived from inside.

Next, when performing heat exchange using the heat exchanger of this embodiment, hydrogen is introduced into the pressure vessel 10 from the hydrogen supply / discharge pipe 21 and the hydrogen is passed through each of the filter-type hydrogen vent pipes 22. To the hydrogen-storing metal material M contained in the pressure vessel 10 through the hydrogen-absorbing metal material M. The hydrogen thus supplied is absorbed by the hydrogen-storing metal material M to form a metal hydride MH, or The hydrogen is released from the metal hydride MH having absorbed therein and returned to the hydrogen storage metal material M, and the hydrogen thus released is discharged from the pressure vessel 10 through the hydrogen supply / discharge pipe 21.

Then, as described above, the hydrogen storage metal material M
Utilizes the heat generated by supplying hydrogen to the metal hydride MH, and transfers this heat to the heat exchange medium flowing through the medium pipe 30 through the heat exchange fins 13 to transfer the heat exchange medium. The heat exchange fins 13 are heated and used as a heat source. Conversely, the heat absorption when hydrogen is released from the metal hydride MH and returned to the hydrogen storage metal material M is used.
Then, the heat of the heat exchange medium flowing through the medium pipe 30 is absorbed by the heat exchange medium, and the heat exchange medium is cooled to perform cooling.

Here, as described above, the hydrogen storage metal material M
To absorb hydrogen and convert it to metal hydride MH,
By repeatedly performing the operation of releasing hydrogen from the metal hydride MH and returning it to the hydrogen storage metal material M, the hydrogen storage metal material M is pulverized as described above, and the hydrogen storage metal material M thus pulverized as described above. Of the pressure vessel 10 held by the holding member 14 and shifted toward the bottom on the upper side, thereby increasing the density.

For this reason, when the hydrogen storage metal material M absorbs hydrogen and becomes the metal hydride MH, the volume expansion is large at the bottom on the upper side of the pressure vessel 10.
Such a volume expansion is absorbed by the cushioning heat insulating material 16 provided on the lower side in the pressure vessel 10 and the pressure vessel 10
There was no deformation itself.

Further, as described above, the heat exchange medium is heated by utilizing the exothermic reaction when the hydrogen storage metal material M supplies hydrogen to become the metal hydride MH, or the metal hydride MH
When the heat exchange medium is cooled by utilizing an endothermic reaction that occurs when hydrogen is released and returns to the hydrogen storage metal material M, heat is generated at the lower side in the pressure vessel 10 by the above-described heat insulating buffer. Insulated by the material 16 and not transmitted to the pressure vessel 10,
Heating or cooling of the pressure vessel 10 itself is reduced, heat loss through the pressure vessel 10 is reduced, and heat loss due to sensible heat of the pressure vessel 10 is also reduced, so that efficient heat exchange can be performed. It became so.

In the heat exchanger of this embodiment,
Although the buffer heat insulating material 16 is arranged in the buffer portion 15 on the lower side in the pressure vessel 10, it is not always necessary to provide the buffer heat insulating material 16 in the buffer portion 15.
Even when the pressure vessel 6 is not provided, the deformation of the pressure vessel 10 is suppressed, the heat loss in the pressure vessel 10 is reduced, and efficient heat exchange can be performed.

[0031]

As described above in detail, in the heat exchanger of the present invention, the hydrogen storage metal material is accommodated in the upper portion of the pressure vessel, and the buffer portion is provided in the lower portion of the pressure vessel. When the hydrogen-absorbing metal material absorbs hydrogen and turns into a metal hydride, even if its volume expands, this volume expansion is absorbed by the buffer provided on the lower side of the pressure vessel, and is absorbed by the pressure vessel. Does not work, and as a result, even if the hydrogen storage metal material is finely divided by the use of this heat exchanger, the volume expansion when the hydrogen storage metal material absorbs hydrogen as in the conventional heat exchanger As a result, the heat exchanger can be stably used for a long time without being deformed or broken.

Further, in the heat exchanger according to the present invention, since the pressure vessel is not deformed by the volume expansion of the hydrogen storage metal material as described above, the hydrogen storage stored in the upper portion of the pressure vessel is performed. By increasing the filling rate of the metal material, efficient heat exchange can be performed.

Further, in the heat exchanger of the present invention, since the buffer is provided on the lower side of the pressure vessel as described above, the heat of the hydrogen storage metal material is transmitted to the pressure vessel through the buffer. When the heat exchange medium flowing through the medium pipe is heated or cooled by the hydrogen storage metal material, the heat loss through the pressure vessel is reduced. Along with
The heat loss due to the sensible heat is reduced, and efficient heat exchange can be performed.

Further, in the heat exchanger of the present invention, since the buffer portion is provided only on the lower side in the pressure vessel where the hydrogen storage metal material tends to be deformed when it absorbs hydrogen and expands in volume, the pressure is reduced. The heat exchanger did not become too large because the container became too large.

Further, in the heat exchanger of the present invention, when a cushioning heat insulating material having a high cushioning property is provided in the buffer portion on the lower side in the pressure vessel, the deformation of the pressure vessel is suppressed by the buffering heat insulating material. Also, the heat transmitted to the pressure vessel through the buffer section is reduced, and the heat loss in the pressure vessel is further suppressed, so that more efficient heat exchange can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a conventional heat exchanger.

FIG. 2 is a schematic cross-sectional view showing a state in which a medium pipe for passing a heat exchange medium is provided in a pressure vessel in a conventional heat exchanger.

FIG. 3 shows a heat exchanger according to one embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view showing a state before a buffer heat insulating material is arranged in a buffer section on a lower side in the pressure vessel.

FIG. 4 shows a heat exchanger according to one embodiment of the present invention.
FIG. 3 is a schematic vertical sectional view showing a state before a buffer heat insulating material is arranged in a buffer section on a lower side in the pressure vessel.

FIG. 5 shows a heat exchanger according to one embodiment of the present invention.
FIG. 4 is a schematic longitudinal sectional view showing a state in which a buffer heat insulating material is arranged in a buffer section on a lower side in the pressure vessel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pressure vessel 14 Holding member 15 Buffer part 16 Buffer heat insulating material 20 Hydrogen supply / discharge means M Hydrogen storage metal material MH Metal hydride

Claims (1)

(57) [Claims] 1. A heat exchanger comprising: a pressure vessel containing a hydrogen storage metal material; and a hydrogen supply / discharge means for supplying hydrogen to the pressure vessel and discharging hydrogen from the pressure vessel. A heat exchanger wherein a metal material is accommodated in an upper portion of the pressure vessel, and a buffer is provided in a lower portion of the pressure vessel.