JPH0220911B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a heat pump device using metal hydrides.

(Prior Art) It is known that certain metals and alloys absorb hydrogen exothermically to form metal hydrides, and that these metal hydrides reversibly and endothermically release hydrogen. In recent years, various heat pump devices have been proposed that utilize the characteristics of such metal hydrides.

Most of these heat pump devices, in principle, use a pair of heat exchangers, each serving as a reaction vessel, for treating metal hydrides with different equilibrium hydrogen decomposition pressures, as described in Japanese Patent Publication No. 55-35616, for example. At the same time, these reaction vessels are connected with a hydrogen flow pipe to form a working pair, and the metal hydride in each reaction vessel is heated or cooled with a heating medium at a predetermined temperature for a certain period of time. , hydrogen is endothermically released from the metal hydride in one reaction vessel of the working pair, this hydrogen is guided to the other reaction vessel via the hydrogen flow pipe, and is exothermically occluded in the metal hydride in this reaction vessel. In this way, heat or cold at a predetermined temperature is extracted as output by utilizing the exothermic or endothermic reaction associated with absorption or release of hydrogen in the metal hydride.

Figure 1 is an example of a cycle diagram showing the operation of the heat pump device as described above. (point A), MH2 is heated to medium temperature TM with a heating medium at a predetermined temperature.
(point B), a pressure difference is created between the hydrogen equilibrium decomposition pressures of MH1 and MH2, hydrogen is released endothermically from MH1, and this hydrogen is exothermically stored in MH2, and then MH1 is heated at a medium temperature. TM (point F) and MH2 at a predetermined temperature TL (point E), a pressure difference of hydrogen equilibrium decomposition pressure is created between MH2 and MH1, hydrogen is released from MH2, and this hydrogen is It is stored in MH1 and uses the endothermic reaction of MH2 to obtain a cold output at a temperature TL. After this, MH1 is heated again to high temperature TH,
Holding MH2 at medium temperature TM completes the cycle.

In addition, instead of heating and cooling the metal hydride in each reaction vessel alternately as described above, hydrogen is supplied under pressure into the reaction vessel to absorb hydrogen, and then the pressure inside the reaction vessel is reduced to absorb hydrogen. By causing each reaction vessel to alternately absorb and release hydrogen,
It is also possible to obtain thermal or cold output, for example
This is already well known as described in Japanese Patent No. 51-82942.

In such conventional heat pump devices, hydrogen transfer between reaction vessels due to absorption and desorption of hydrogen by metal hydrides is, for example, described in the above-mentioned Japanese Patent Application Laid-Open No.
As described in Publication No. 82942, it is usually regulated by a solenoid valve.

Therefore, a typical conventional two-cylinder heat pump device has a first reaction vessel 11 filled with MH1 and a second reaction vessel 11 filled with MH2, as shown in FIG.
The reaction vessel 12 is connected to the first hydrogen flow pipe 13 and the second hydrogen flow pipe 13.
Each hydrogen flow pipe is equipped with control valves 15 and 16 that can control opening and closing, and the first hydrogen flow pipe 13 is connected to the hydrogen flow pipe 14 from MH1.
The second hydrogen flow pipe 14 is equipped with check valves 17 and 18 that allow only hydrogen transfer to MH2, and check valves 17 and 18 that allow only hydrogen transfer from MH2 to MH1. The hydrogen transfer between containers is controlled by opening and closing.

As the above-mentioned control valves, solenoid valves are widely used because they are smaller, simpler, and cheaper than conventional ones.However, as is well known, ordinary solenoid valves are generally used in pipes. It only has the function of opening and closing the flow of fluid in one direction in the channel, and therefore requires the provision of a check valve to block the flow in the opposite direction. Therefore, even in the simple so-called two-cylinder type heat pump device described above, in order to regulate the hydrogen transfer between the containers according to the reaction of the metal hydride in each reaction container, it is necessary to install an electromagnetic device in each hydrogen flow pipe. Since one valve and one check valve are required, in a practical three-cylinder type or more multi-cylinder type heat pump device,
The number of electromagnetic valves and check valves required to regulate hydrogen transfer between reaction vessels becomes extremely large, which complicates the equipment configuration and significantly reduces the reliability of the equipment. Increased risk of leakage. On the other hand, if a high-grade control valve, such as an electric valve, is used, the risk of failure or hydrogen leakage may be eliminated to some extent, but the control system will be complicated and the device will be expensive.

(Object of the Invention) The present invention has been made in order to solve the above-mentioned problems in conventional heat pump devices. The purpose is to provide a heat pump device with high performance.

(Summary of the Invention) The heat pump device of the present invention is characterized in that the (m+
1) Connect each metal hydride in the reaction vessel with a hydrogen flow pipe so that the hydrogen equilibrium decomposition pressure of the metal hydride in the m-th reaction vessel (1≦m≦n) is higher than that of the metal hydride in the m-th reaction vessel. , in a heat pump device in which an nth reaction vessel and a first reaction vessel are connected by a hydrogen flow pipe, (a) each hydrogen flow pipe is connected to an mth to (m+1)th reaction vessel; (b) Prohibit hydrogen from moving from the (m+1)th reaction vessel to the mth reaction vessel by providing a check valve that allows hydrogen to flow only in the direction of the (m+1)th reaction vessel; A control valve capable of controlling opening and closing of at least one of a hydrogen flow pipe connecting the reaction container and the first reaction container, and a hydrogen flow pipe connecting the first reaction container and the second reaction container. (c) Sequentially release hydrogen from the metal hydride in the m-th reaction vessel, guide this hydrogen to the (m+1)-th reaction vessel through a check valve, and release the metal hydrogen in this vessel. In this way, hydrogen is released from the metal hydride in the n-th reaction vessel, and this hydrogen is introduced into the first reaction vessel through the hydrogen flow pipe, and the metal hydride in this vessel is It is characterized in that cold heat is obtained from the n-th reaction vessel or warm heat is obtained from the first reaction vessel.

(Structure of the Invention) The heat pump device of the present invention will be described below based on the drawings. In the following, as mentioned above, the m-th metal hydride is represented by MHm, which is represented by m in the drawings, and MH (m+1 )
is chosen to have a hydrogen equilibrium decomposition pressure higher than MHm in the operating temperature range of the device.

FIG. 3 shows an embodiment of the three-cylinder heat pump device of the present invention, which is suitable for obtaining cold output.

The first reaction vessel 21 filled with MH1 and the MH1
The second reaction vessel 22 filled with MH3 is connected to the second reaction vessel 22 by a hydrogen flow pipe 25 equipped with a check valve 24 that allows hydrogen to move only in the direction from the former to the latter. The third reaction vessel 23 filled with hydrogen is also connected by a hydrogen flow pipe 27 equipped with a check valve 26 that only allows hydrogen to move from the former to the latter.
Further, the third reaction vessel 23 and the first reaction vessel 21 are connected by a hydrogen flow pipe 29 equipped with a control valve, for example, a solenoid valve 28.

The operation of this device will be explained based on the cycle diagram shown in FIG. First, the hydrogen flow pipe 29 connecting the first reaction container 21 and the third reaction container 23 is
The solenoid valve 28 provided above is closed, and the first
MH1 in the second reaction vessel 21 is heated to a predetermined high temperature TH (point A), MH2 in the second reaction vessel 22 is maintained at a predetermined medium temperature (point B), and the hydrogen equilibrium decomposition pressure of MH3 is raised to MH2. In order to keep it higher than that, for example, by also keeping MH3 in the third reaction vessel 23 at medium temperature TM (point D), MH1 and
A pressure difference occurs in the hydrogen equilibrium decomposition pressure between MH2 and
MH1 endothermically releases hydrogen, this hydrogen is fed into the second reaction vessel through hydrogen flow pipe 25 and check valve 24, and MH2 exothermically stores this hydrogen. In this reaction, as mentioned above, MH3
is kept at a medium temperature, and therefore the hydrogen equilibrium decomposition pressure is kept higher than that of MH2, so MH2
Hydrogen migration from MH3 toward MH3 does not occur. Also, since the solenoid valve 28 is closed, during this time,
MH1 to MH3 regardless of the temperature of MH3
No hydrogen transfer occurs. After this hydrogen transfer from A to B is completed, MH1 is cooled to intermediate temperature TM (point F).

After this hydrogen transfer from A to B is completed, the MH2 in the second reaction vessel 22 is heated to a high temperature TH (point C), and is maintained at a medium temperature TM as described above.
When a pressure difference of hydrogen equilibrium decomposition pressure is created between MH3 (point D), MH2 releases hydrogen endothermically,
This hydrogen is led to the third reaction vessel through the hydrogen flow pipe 27 and the check valve 26, and MH3 absorbs this hydrogen endothermically. During this hydrogen transfer, the solenoid valve 2
Since 8 is closed, hydrogen transfer from MH3 to MH1 does not occur.

After this hydrogen transfer reaction from C to D is completed, when the solenoid valve 28 is opened, MH1 is at a medium temperature as described above.
Since it is kept at TM (point F), MH3 and MH
1, a pressure difference of hydrogen equilibrium decomposition pressure occurs between MH
3 emits hydrogen endothermically at low temperature TL (point E), and leads this hydrogen flow pipe 29 to the first reaction vessel via a solenoid valve 28, where MH1 absorbs this hydrogen exothermically ( Point F).

Then, MH1 is brought to temperature TH, MH2 and MH
The cycle is completed by returning 3 to temperature TM, respectively.

Therefore, the above heat pump device uses a high temperature TH heat source to obtain low temperature TL cold heat as output, and can be used for air conditioning, for example, but in the case of a conventional two-cylinder type device, A→ B→
In contrast to the cycle E'→F, the apparatus of the present invention performs the cycle A→B→C→D→E→F, so it is possible to obtain cold output at a lower temperature. .

FIG. 5 shows a multi-cylinder heat pump device consisting of n cylinders instead of the three-cylinder type described above,
The m-th reaction vessel and the (m+1)-th reaction vessel are connected by a hydrogen flow pipe 32 equipped with a check valve 31 that allows hydrogen to move only from the former toward the latter reaction vessel. The n-th reaction vessel and the first reaction vessel are connected through a hydrogen flow pipe 34 equipped with a solenoid valve 33.

The operation of such a multi-cylinder heat pump device is similar to that described above, and as shown in the cycle diagram in Figure 6, hydrogen is transferred from MH1 to the next stage metal having a higher hydrogen equilibrium decomposition pressure. is transferred sequentially to the hydride, from MH(n-1) to MHn
After hydrogen transfer to
Hydrogen transfer to MH1 completes the cycle, and cold output is obtained from the hydrogen storage reaction of MHn. Incidentally, the more stages the metal hydride is used, the lower the temperature of the cold output can be obtained.

FIG. 7 shows an embodiment of the three-cylinder heat pump device of the present invention, which is suitable for obtaining thermal output. a first reaction vessel 41 filled with MH1;
A second reaction vessel 42 filled with MH2 is connected to the second reaction vessel 42 by a hydrogen flow pipe 46 equipped with a check valve 44 and a solenoid valve 45 that only allow hydrogen to move from the former to the latter. and the third filled with MH3
The third reaction vessel 43 is connected to the third reaction vessel 43 by a hydrogen flow pipe 48 equipped with a check valve 47 that only allows hydrogen to move from the former to the latter.
A hydrogen flow pipe 49 without a valve is connected to the reaction vessel.

In operation of this device, as shown in the cycle diagram shown in FIG. 8, first, the solenoid valve 45 is opened, MH1 is heated to a predetermined medium temperature TM (point A),
When MH2 and MH3 are kept at a predetermined low temperature TL (points B and D, respectively), MH1 releases hydrogen endothermically due to the difference in hydrogen equilibrium decomposition pressure between MH1 and MH2, and this Hydrogen is led to the second reaction vessel 42 through the hydrogen flow pipe 46 through the electromagnetic valve 45 and the check valve 44, and MH2 exothermically occludes this hydrogen. During this reaction, as mentioned above, MH3 is also kept at a low temperature TL, and therefore the hydrogen equilibrium decomposition pressure is kept higher than that of MH2, so MH2
No hydrogen transfer occurs from to MH3. Also, during this period, MH3 has a higher hydrogen equilibrium decomposition pressure than MH1 and is in a state after hydrogen has been released, so MH3
3 and MH1 are connected by a hydrogen flow pipe 49 that does not have a valve, but no hydrogen transfer occurs through this hydrogen flow pipe. After the completion of this reaction, MH
1 is heated to a high temperature TH.

After this hydrogen transfer from A to B is completed, MH2 is heated to medium temperature TM (point C) and then heated to low temperature as described above.
When a pressure difference is created in the hydrogen equilibrium decomposition pressure between MH3 (point D) maintained at TL, MH2 endothermically releases hydrogen, and this hydrogen passes through the hydrogen flow pipe 48 and the check valve 47. The hydrogen is then led to a third reaction vessel, where the hydrogen is absorbed endothermically by MH3. This C
During hydrogen transfer from to D, regardless of the temperature of MH1, the check valve 44 on the hydrogen flow pipe 44 allows
Hydrogen transfer from MH2 to MH1 is blocked. Further, since MH1 is kept at a temperature TH higher than that of MH3, and the hydrogen equilibrium decomposition pressure is kept higher than that of MH3, no hydrogen transfer from MH3 to MH1 occurs.

After this reaction is completed, the solenoid valve 45 is closed and MH3
is heated to medium temperature TM, and the temperature after releasing MH3 and hydrogen is
When a pressure difference is created in the hydrogen equilibrium decomposition pressure between TH and MH1, MH3 endothermically releases hydrogen, which is supplied to MH1 through the hydrogen flow pipe 49, and MH1
absorbs this hydrogen exothermically. During this time, MH3
Hydrogen movement from to MH1 is prohibited by the check valve 47, and since the solenoid valve 45 is closed,
No hydrogen transfer occurs from MH1 to MH2. After this, MH1 is returned to the temperature TM, and MH2 and MH3
The cycle is completed by returning the temperature to TL.

Therefore, according to the heat pump device described above,
By using a medium-temperature heating medium as a driving heat source, it is possible to obtain thermal heat at a predetermined temperature TH as an output, but in particular, in the case of a conventional two-cylinder heat pump device, C→
In contrast to the cycle D→E→F', according to the apparatus of the present invention, the cycle A→B→C→D→E→F
Since this cycle is performed, higher temperature thermal output can be obtained.

FIG. 9 shows a multi-cylinder heat pump device consisting of n cylinders instead of the three-cylinder type described above,
The (m-1)th reaction vessel and the mth reaction vessel are connected by a hydrogen flow pipe 52 equipped with a check valve 51 that allows hydrogen to flow from the former toward the latter reaction vessel. The n-th reaction vessel and the first reaction vessel are connected by a hydrogen flow pipe 53 that does not have a valve, and the first and second reaction vessels are connected to the check valve 44. In addition, a hydrogen flow pipe 46 equipped with a solenoid valve 45 is connected.

The operation of such a multi-cylinder heat pump device is similar to that described above, and as shown in the cycle diagram of FIG. After hydrogen transfer from MH(n-1) to MHn, hydrogen transfer from MHn to MH1 completes the cycle.

(Effects of the Invention) As described above, in the heat pump device of the present invention, metal hydrides having different hydrogen equilibrium decomposition pressures in a predetermined operating temperature range are arranged such that the hydrogen equilibrium decomposition pressures of the metal hydrides are successively increased. The hydrogen is released from the metal hydride in the first reaction vessel, and this hydrogen is sequentially transferred to the metal hydride in the next stage where the hydrogen equilibrium decomposition pressure is higher, and finally from the final stage reaction vessel. Since hydrogen is transferred to the first reaction vessel, it is possible to obtain a lower or higher temperature output compared to a two-cylinder heat pump device, and the number of valves included in the device can be reduced by reducing the number of valves included in the device. Since the reaction characteristics are minimized, the device configuration can be simplified, the device can be made inexpensive, and the reliability of the device can be significantly improved. Also, the risk of hydrogen leakage is greatly reduced.

[Brief explanation of drawings]

Figure 1 is a cycle diagram to explain the operation of a conventional two-cylinder heat pump device, and Figure 2 is a cycle diagram for explaining the operation of a conventional two-cylinder heat pump device.
FIG. 3 is a device configuration diagram showing a typical example of a cylinder type heat pump device, FIG. 3 is a device configuration diagram showing an embodiment of the heat pump device of the present invention, and FIG. 4 is a cycle line for explaining the operation of the device in FIG. 3. 5 is a device configuration diagram showing a multi-cylinder heat pump device corresponding to FIG. 3, FIG. 6 is a cycle diagram showing its operation, and FIG. 7 is another embodiment of the heat pump device of the present invention. 8 is a cycle diagram for explaining the operation of the device in FIG. 7, FIG. 9 is a device configuration diagram showing a multi-cylinder heat pump device corresponding to FIG. 6, and FIG. 10 is a cycle diagram showing its operation. 21, 22, 23... reaction container, 24, 26...
...Check valve, 25, 27, 29...Hydrogen flow pipe, 2
8... Solenoid valve, 31... Check valve, 32, 34...
Hydrogen flow pipe, 33... Solenoid valve, 41, 42, 43
... Reaction container, 44, 47 ... Check valve, 45 ...
Solenoid valve, 48, 49...Hydrogen flow pipe, 51, 54
...Check valve, 52, 53...Hydrogen flow pipe, 55...
…solenoid valve.

Claims (1)

[Claims] 1 n types of hydrogen equilibrium decomposition pressures different from each other (n≧
3), the hydrogen equilibrium decomposition pressure of the metal hydride in the (m+1)th (1≦m≦n) reaction vessel is the mth
A heat pump formed by connecting each of the n-th reaction vessels with a hydrogen flow pipe so that the metal hydride in the first reaction vessel is larger than the metal hydride in the second reaction vessel, and connecting the n-th reaction vessel and the first reaction vessel with a hydrogen flow pipe. In the apparatus, (a) each hydrogen flow pipe is provided with a check valve that allows hydrogen to flow only in the direction from the m-th reaction vessel to the (m+1)-th reaction vessel; (b) a hydrogen flow pipe connecting the n-th reaction vessel and the first reaction vessel; A control valve capable of opening and closing is provided on at least one side of the hydrogen flow pipe connecting the m-th reaction vessel, and (c) hydrogen is sequentially released from the metal hydride in the m-th reaction vessel; is introduced into the (m+1)th reaction vessel through a check valve, and is occluded by the metal hydride in this vessel, and in this way, hydrogen is released from the metal hydride in the nth reaction vessel, This hydrogen is introduced into the first reaction vessel through the hydrogen flow pipe, and is absorbed by the metal hydride in this vessel, and cold heat is obtained from the nth reaction vessel or warm heat is obtained from the first reaction vessel. A heat pump device characterized by: