JPH0784966B2 - Heat pump using metal hydride and control method thereof - Google Patents

Description

The present invention relates to a heat pump using a metal hydride and a control method thereof.

(B) Conventional Technology As a conventional heat pump using a metal hydride, there is, for example, one disclosed in Japanese Patent Publication No. 58-19955. The cooling and heating apparatus shown therein is provided with two sets of cooling and heating blocks, each of which is a set of two heat exchangeable containers each containing two kinds of metal hydrides having different hydrogen equilibrium pressures, which are connected to each other. Are alternately heated and cooled, and heat and heat are alternately absorbed and radiated in the other container of each set, and the other container is alternately used as a cooling and heating source for continuous cooling or heating. In the case of this air conditioner, if one container is viewed, the process of feeding hydrogen gas and the process of feeding hydrogen gas are repeated alternately. The temperature of the metal hydride rises in the first step, and the temperature decreases in the second step. In the other container, the same steps as above are repeated with the phases shifted.

(C) Problems to be solved by the invention In such a conventional heat pump using a metal hydride, immediately after the heating / cooling of one container is reversed to reverse the flow direction of hydrogen gas, Since the high temperature side container is cooled and the low temperature side container is heated, there is a problem that the heat loss is very large. Immediately after the reversal of heating / cooling, for example, a high-temperature heat medium is temporarily supplied during cooling, and smooth continuous cooling / heating cannot be performed. The present invention aims to solve such problems.

(D) Means for Solving the Problems The present invention uses five heat exchangers for metal hydrides to store the heat remaining in the heat exchangers for metal hydrides after completion of the hydrogen storage reaction into hydrogen storage. The above-mentioned problems are solved by using it for heating another heat exchanger for metal hydride during the reaction. That is, the heat pump using the metal hydride according to the present invention comprises three heat exchangers (11, 12 and 13) for the first heat medium for the metal hydride and two heat exchangers for the second heat medium. Hydrogen heat exchanger (114 and 115) and hydrogen gas passage switching device (41, 42, 43, 44) capable of switching the moving state of hydrogen gas between these five metal hydride heat exchangers in total. , 45, 4
6, 147, 148, 149 and 150), the heat medium passages (21, 22 and 23) of the three heat exchangers for metal hydride and the first heat medium low temperature side heat exchange unit (15) and Heat medium passages (25 and 26) of the first heat medium high temperature side heat exchange unit (16)
First heat medium passage switching device (5
1, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 6
3, 64 and 65) and a first heat medium pump (17 and 1) for circulating the first heat medium through the first heat medium passage switching device.
8), the heat medium passages (124 and 125) of the two heat exchangers for metal hydride, the second heat medium low temperature side heat exchange unit (130), and the second heat medium high temperature side heat exchange unit (13
4) A second heat medium passage switching device (151, 152, 153, 154) for switching the connection state with the heat medium passages (132 and 136).
155, 156, 157 and 158) and a second heat medium pump (170 and 172) for circulating the second heat medium through the second heat medium passage switching device. The reference numerals in parentheses indicate the corresponding members in the embodiments described later.

Further, in the method for manufacturing a heat pump using metal hydride according to the present invention, the second heat medium passage switching device and the hydrogen gas passage switching device are controlled so as to control the third metal hydride heat exchanger (13). From the fourth to the fifth metal hydride heat exchanger (114 and 115) to move the hydrogen gas and from the other of the fourth and fifth metal hydride heat exchangers to the first metal hydride The hydrogen gas is moved to the heat exchanger (11), the movement of hydrogen in the second metal hydride heat exchanger (12) is stopped, and the heat for the second metal hydride is changed by the first heat medium passage switching device. The first heat medium circulates in the order of the exchanger → the heat exchanger for the first metal hydride → the high temperature side heat exchange unit for the first heat medium → the heat exchanger for the second metal hydride
A first heat medium is circulated in the order of a heat medium passage and a third metal hydride heat exchanger → a first heat medium low temperature side heat exchange unit → a third metal hydride heat exchanger. By controlling the first step of forming the heat medium passage, the second heat medium passage switching device, and the hydrogen gas passage switching device,
The hydrogen gas is moved from the heat exchanger for the second metal hydride to one of the heat exchangers for the fourth and fifth metal hydrides and the third to the third heat exchangers for the fourth and fifth metal hydrides. The hydrogen gas is moved to the heat exchanger for metal hydride, the movement of hydrogen in the heat exchanger for first metal hydride is stopped, and the heat exchanger for first metal hydride is changed by the first heat medium passage switching device. → The heat exchanger for the third metal hydride → The high temperature side heat exchange unit for the first heat medium → The first heat medium passage through which the first heat medium circulates is formed in the order of the heat exchanger for the first metal hydride,
A first heat medium passage through which the first heat medium circulates is formed in the order of the second metal hydride heat exchanger → the first heat medium low temperature side heat exchange unit → the second metal hydride heat exchanger. By controlling the second step, the second heat medium passage switching device, and the hydrogen gas passage switching device, either one of the first metal hydride heat exchanger to the fourth and fifth metal hydride heat exchangers is controlled. The hydrogen gas in the heat exchanger for the third metal hydride and the hydrogen gas in the heat exchanger for the second metal hydride from the other of the heat exchangers for the fourth and fifth metal hydrides to the heat exchanger for the second metal hydride. The movement is stopped, and by the first heat medium passage switching device, the third metal hydride heat exchanger → the second metal hydride heat exchanger → the first heat medium high temperature side heat exchange unit →
A first heat medium passage through which the first heat medium circulates is formed in the order of the third metal hydride heat exchanger, and the first metal hydride heat exchanger → the first heat medium low temperature side heat exchange unit → The gist is to sequentially repeat the above first to third steps of the third step of forming the first heat medium passage through which the first heat medium circulates in the order of the first metal hydride heat exchanger.

(E) Action Regarding the heat exchanger for the first metal hydride, the temperature rises in the first step, and then the first heat exchanger enters the heat-generating third metal hydride heat exchanger in the second step. Since the heat medium flows, heat is taken out from the first metal hydride heat exchanger. In the third step, heat absorption is started and the temperature of the first metal hydride heat exchanger is rapidly lowered. As described above, in the second step, the heat of the heat exchanger for the first metal hydride is absorbed and the amount of heat acquired increases. While the heat exchanger for the first metal hydride is absorbing heat in the second step, heat is generated in the heat exchanger for the third metal hydride, so that the temperature rising characteristic does not deteriorate. . This effect is 1 / even in the other two metal hydride heat exchangers.
It is performed by shifting the phase by 3. As a result, the amount of heat acquired can be increased without deteriorating the temperature rise characteristics.

(F) Embodiment An embodiment of the present invention is shown in FIG. First metal hydride heat exchanger 11 for first heat medium, second metal hydride heat exchanger
The heat exchanger 13 for 12 and the third metal hydride, the heat exchanger 114 for the fourth metal hydride and the heat exchanger 115 for the fifth metal hydride for the second heat medium are hydrogen gas passage switching devices. Some valves 41, 42, 43, 44, 45, 46, 147, 148, 149 and 150
Are connected by the valve 4 as shown in FIG.
1, 42, 43, 44, 45, 46, 147, 148, 149 and 150 by controlling the opening and closing of the metal hydride heat exchanger 11, 12,
Hydrogen gas can be moved between 13, 114 and 115. The metal hydride heat exchangers 11, 12, 13, 114 and 115 are filled with metal hydride. The heat medium passages 21, 22 and 22 in the metal hydride heat exchangers 11, 12 and 13, respectively.
23 is a low temperature side heat exchange unit 15 for the first heat medium (for example, a heat source side heat exchange unit when used as a heating device,
Alternatively, when used as a refrigerating apparatus, the heat medium passage 25 of the freezing compartment side heat exchange unit, and the first heat medium high temperature side heat exchange unit 16 (for example, when used as a heating apparatus, indoor heat exchange unit) Further, when it is used as a refrigerating apparatus, it is connected to the heat medium passage 26 of the heat source side heat exchange unit) as shown in FIG. In the middle of the piping, as shown, valves 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, which are first heat medium passage switching devices,
63, 64 and 65, and first heat medium pumps 17 and 18 are provided. The heat medium passages 124 and 125 in the metal hydride heat exchangers 114 and 115 are the heat medium passages 132 of the second heat medium low temperature side heat exchange unit 130 and the second heat medium high temperature side heat exchange, respectively. It is connected to the heat medium passage 136 of the unit 134 as shown in FIG. In the middle of the pipe, as shown in the figure, a valve 15 which is a second heat medium passage switching device is provided.
1, 152, 153, 154, 155, 156, 157 and 158, and second heat medium pumps 170 and 172 are provided. Valve 41,
Opening and closing 42, 43, 44, 45, 46, 147, 148, 149 and 150, valves 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 6
Opening and closing 2, 63, 64 and 65 and valves 151, 152, 153, 15
Opening / closing of 4, 155, 156, 157 and 158 is performed by a command from a control device (not shown).

Next, the operation of this embodiment will be described.

First, in the first step, the valves 45 and 150 are opened so as to send hydrogen gas from the third metal hydride heat exchanger 13 to the fifth metal hydride heat exchanger 115, and the fourth metal hydride heat exchanger 115 is opened. The valves 42 and 14 are arranged so that the hydrogen gas moves from the heat exchanger 114 to the first metal hydride heat exchanger 11.
7 open and other valves 41, 43, 44, 46, 148 and 14
9 is closed. Further, the valves 60, 56, 53, 64 and 62 are opened to open the valves 51, 52, 54, 55, 57, 58, 59, 61, 63 and 65.
Is closed. Further, the valves 156, 158, 151 and 153 are opened and the valves 155, 157, 152 and 154 are closed. The flow of hydrogen gas and heat medium in this state is shown in FIG. The heat medium includes the first heat medium high temperature side heat exchange unit 16 → the second metal hydride heat exchanger 12 → the first metal hydride heat exchanger 11 → the first heat medium high temperature side heat exchange unit 16. It will cycle in order. Further, the heat medium flows between the first heat medium low temperature side heat exchange unit 15 and the third metal hydride heat exchanger 13. Further, between the fifth metal hydride heat exchanger 115 and the second heat medium low temperature side heat exchange unit 130, and between the fourth metal hydride heat exchanger 114 and the second heat medium high temperature side heat exchange. The second heat medium flows to and from the unit 134. In this state, hydrogen gas is released in the third metal hydride heat exchanger 13, and heat is taken from the first heat medium in the heat medium passage 23. As a result, the cooled first heat medium is supplied to the heat medium passage 25.
Further, hydrogen gas is stored in the first metal hydride heat exchanger 11, and heat is released to the heat medium passage 21. As a result, the heated first heat medium is supplied to the heat medium passage 26. That is, the low temperature side heat exchange unit 15 for the first heat medium
The heat is absorbed by the first heat medium high temperature side heat exchange unit 16, and the heat is released.

When the hydrogen gas pressure in the first metal hydride heat exchanger 11 reaches a predetermined value (or after a predetermined time elapses), the first step is switched to the first intermediate step. That is, the valves 151, 15
2, 153, 154, 155, 156, 157 and 158 are closed and valves 41, 42, 43, 44, 45, 46, 147, 148, 149 and 150 are closed.
Is closed. However, the open state of the valves 60, 56, 53, 64 and 62 and the valves 51, 52, 54, 55, 57, 58, 59, 61, 63.
The closed states of 65 and 65 are maintained as in the first step. This state is shown in FIG. Immediately after the first intermediate step is started, the metal hydride in the third metal hydride heat exchanger 13 is in a low temperature state, and the metal hydride in the first metal hydride heat exchanger 11 is in a high temperature state. . First metal hydride heat exchanger 11
The heat is absorbed by the first heat medium flowing through the heat medium passage 21 and the temperature of the metal hydride in the first metal hydride heat exchanger 11 gradually decreases. In this state, when a predetermined time has passed, the second step is started.

In the second step, the valves 43, 148, 149 and 46 are opened and the valves 41, 42, 44, 45, 147 and 150 are closed. Further, the valves 155, 157, 152 and 154 are opened, and the valves 151, 15
3, 156 and 158 are closed. Valves 55, 51, 6 at the same time
3, 59 and 57 are opened and valves 52, 53, 54, 56, 58, 6
0, 61, 62, 64 and 65 are closed. This state is shown in FIG. Hydrogen moves from the metal hydride heat exchanger 12 to the fourth metal hydride heat exchanger 114, and from the fifth metal hydride heat exchanger 115 to the third metal hydride heat exchanger 13. The heat exchanger 12 for metal hydride absorbs heat, and the heat exchanger 13 for third metal hydride generates heat. The first heat medium is the high temperature side heat exchange unit 16 for the first heat medium → the heat exchanger 11 for the first metal hydride → the heat exchanger 13 for the third metal hydride
→ The first heat medium high temperature side heat exchange unit 16 is circulated in this order. Also, the low temperature side heat exchange unit for the first heat medium
The first heat medium flows between 15 and the second metal hydride heat exchanger 12. Although hydrogen is not transferred in the heat exchanger 11 for the first metal hydride, the heat held up to the second step is generated by the first heat medium before entering the heat exchanger 13 for the third metal hydride. Be absorbed. The first heat medium is further heated in the third metal hydride heat exchanger 13. When a predetermined time elapses in the state of the second step, the second intermediate step is started.

In the second intermediate step, the valves 41, 42, 43, 44, 45 and 46 are closed, and the valves 151, 152, 153, 154, 155, 156,
157 and 158 are closed. However, valves 55, 51, 63,
59 and 57 are left open, valves 52, 53, 54, 56, 5
8, 60, 61, 62, 64 and 65 are kept closed, and the first heat medium passage is held in the same state as in the second step. In this state, the temperature of the metal hydride in the third metal hydride heat exchanger 13 gradually decreases, and the temperature of the metal hydride in the second metal hydride heat exchanger 12 gradually increases. During this time, the heat quantity remaining in the first metal hydride heat exchanger 11 is absorbed by the first heat medium flowing through the heat medium passage 21 of the first metal hydride heat exchanger 11. When a predetermined time has elapsed, the second intermediate process is switched to the third process.

In the third step, the valves 41, 150, 147 and the valve 44 are opened and the valves 42, 43, 45, 46, 148 and 149 are closed.
Valves 156, 158, 151 and 153 are opened and valves 152, 1
54, 155 and 157 are closed. At the same time, the valves 65, 61, 58, 54 and 52 are opened and the valves 51, 53, 5 are opened.
5, 56, 57, 59, 60, 62, 63 and 64 are closed. This state is shown in FIG. Hydrogen moves from the first metal hydride heat exchanger 11 to the fifth metal hydride heat exchanger 115, and from the fourth metal hydride heat exchanger 114 to the second metal hydride heat exchanger 12. After moving, the first metal hydride heat exchanger absorbs heat, and the second metal hydride heat exchanger 12 generates heat. The first heat medium is the high temperature side heat exchange unit for the first heat medium 16 → the third metal hydride heat exchanger 13 → the second metal hydride heat exchanger 12 → the first heat medium high temperature side heat exchange unit 16 Cycle in order. A heat exchanger for the first metal hydride
11 between the first heat medium low temperature side heat exchange unit 15 and the first heat medium
The heat carrier circulates. The first heat medium that has absorbed the heat remaining in the third metal hydride heat exchanger 13 enters the second metal hydride heat exchanger 12 and is further heated. Next, when a predetermined time elapses, the process is switched to the third intermediate process.

In the third intermediate step, valves 41, 42, 43, 44, 45, 46, 14
7, 148, 149 and 150 are closed. Also, valves 151, 1
52, 153, 154, 155, 156, 157 and 158 are closed. However, valves 65, 61, 58, 54 and 52 are left open,
Also valves 51, 53, 55, 56, 57, 59, 60, 62, 63 and 64
Is kept closed and the same state as in the third step is maintained. This state is shown in FIG. Even in this state, the first heat medium enters the second metal hydride heat exchanger 12 after absorbing the residual heat quantity of the third metal hydride heat exchanger 13. When a predetermined time has passed in the third intermediate step, the process returns to the first step again,
The same operation is repeated thereafter. However, since the hydrogen gas is moved in a predetermined combination between the three metal hydride heat exchangers 11, 12 and 13 and the two metal hydride heat exchangers 114 and 115, it is the same every two cycles. The combination of the metal hydride heat exchangers for exchanging hydrogen gas with each other is not the same even in the same process in adjacent cycles.

FIG. 8 shows the temperatures of the first heat medium at the outlets of the heat exchangers 11, 12 and 13 for metal hydrides in the above respective steps.
For example, the temperature change of the first metal hydride heat exchanger 11 is as follows. First, in the first step, hydrogen is fed in, and the temperature rises due to the hydrogen storage reaction, reaching the point a _{0 to the} point a ₁ . Then, when the first intermediate step starts, the hydrogen storage reaction slows or stops, and the temperature gradually decreases to the temperature at point a ₂ . Then, during the second step and the second intermediate step, the temperature further decreases (a ₂ → a ₃ → a ₄ ) and becomes almost equal to the inlet temperature of the heat medium on the high temperature side. When the third step starts, the temperature further decreases due to the hydrogen releasing reaction and reaches the point a ₅ . Then the third
Hydrogen releasing reaction when the intermediate step is started is or stopped slowly, the temperature gradually rises, the temperature of a _6-point. Regarding the heat exchanger 11 for the first metal hydride, the temperature change as described above is repeated. The second metal hydride heat exchanger 12 and the third metal hydride heat exchanger 13 show similar changes in a state where the phases are shifted by 1/3. By the above operation,
For example, the high-temperature side heat medium enters the heat exchanger 11 for the first metal hydride that was at a high temperature in the first intermediate step in the second step and the second intermediate step, and remains in the heat exchanger 11 for the first metal hydride. Heat is recovered and then the heat exchanger for the third metal hydride 13
Therefore, the heat remaining in the first metal hydride heat exchanger 11 can be recovered without lowering the high temperature side heat medium inlet temperature. That is, the amount of acquired heat can be increased without deteriorating the temperature rise characteristics.

In the embodiment described above, after the first step, the second step, and the third step, the first intermediate step, the second intermediate step, and
Although the third intermediate step is provided, the same effect can be obtained by omitting them and repeating the order of the first step → second step → third step → first step. However, it is more advantageous to provide the intermediate step in terms of the efficiency of the amount of heat acquired. Further, the terms “first heat medium” and “second heat medium” are used to indicate that the systems of the heat medium are different, but these are the same,
Of course, it may be water, for example.

(G) Effect of the Invention As described above, according to the present invention, one heat exchanger for metal hydride heat exchange is performed while two heat exchangers for metal hydride heat release and absorption are performed. Since the heat remaining in the vessel is recovered, it is possible to increase the amount of heat to be obtained without lowering the temperature raising capability, and the thermal efficiency is greatly improved.

[Brief description of drawings]

FIG. 1 shows a heat pump according to the present invention, FIG. 2 shows a first step of the heat pump, FIG. 3 shows a first intermediate step of the heat pump, and FIG. 4 shows a second step of the heat pump. Fig. 5 is a diagram showing a second intermediate step of the heat pump, Fig. 6 is a diagram showing a third step of the heat pump,
FIG. 7 is a diagram showing a third intermediate step of the heat pump, and FIG. 8 is a diagram showing temperature changes in the heat exchanger for metal hydride according to the present invention. 11 ... Heat exchanger for first metal hydride, 12 ... Heat exchanger for second metal hydride, 13 ... Heat exchanger for third metal hydride, 114 ... Heat exchange for fourth metal hydride Bowl, 115 ... Fifth
Heat exchanger for metal hydride, 15 ... First heat medium low temperature side heat exchange unit, 16 ... First heat medium high temperature side heat exchange unit, 130 ... Second heat medium low temperature side heat exchange unit, 134 ...
… Second heat medium high-temperature side heat exchange unit, 21,22,23 …… heat medium passage, 25,26 …… heat medium passage, 132,136 …… heat medium passage, 41,42,43,44, 45,46,147,148,149,150 ... Valve, 51,52,53,54,55,56,57,58,59,60,61,62,63,64,65
...... Valve, 151,152,153,154,155,156,157,158 …… Valve, 17,18 …… First heat medium pump, 170,172 …… Second
Pump for heat medium.

Claims (3)

[Claims] 1. A heat exchanger for three metal hydrides for a first heat medium, two heat exchangers for a metal hydride for a second heat medium, and a total of five metal hydrides. Gas passage switching device capable of switching the moving state of hydrogen gas between heat exchangers for heat, heat medium passages of the three heat exchangers for metal hydride and low temperature side heat exchange unit for first heat medium And a first heat medium passage switching device that switches a connection state with the heat medium passage of the first heat medium high temperature side heat exchange unit, and a first heat medium that circulates through the first heat medium passage switching device. A heat medium pump, a heat medium passage of the two metal hydride heat exchangers, a heat medium passage of the second heat medium low temperature side heat exchange unit, and a second heat medium high temperature side heat exchange unit A second heat medium passage switching device and a second heat medium passage switching device for switching connection states of Heat pump utilizing a metal hydride having a second heat medium pump for circulating the second heat medium by. 2. A first, a second and a third heat exchanger for metal hydride for the heat medium, and a fourth and a fifth heat exchanger for metal hydride for the second heat medium, A hydrogen gas passage switching device capable of switching the moving state of hydrogen gas among the first, second, third, fourth, and fifth heat exchangers for metal hydrides;
A connection state between the heat medium passages of the second and third metal hydride heat exchangers and the heat medium passages of the first heat medium low temperature side heat exchange unit and the first heat medium high temperature side heat exchange unit is shown. A first heat medium passage switching device for switching, a first heat medium pump for circulating the first heat medium through the first heat medium passage switching device, and the fourth and fifth metal hydride heat exchangers. A second heat medium passage switching device for switching a connection state between the heat medium passage and the heat medium passages of the second heat medium low temperature side heat exchange unit and the second heat medium high temperature side heat exchange unit, and a second heat medium. A heat pump control method using a metal hydride, comprising: a second heat medium pump that circulates the second heat medium through the medium passage switching device; and a second heat medium passage switching device and a hydrogen gas passage switching device. By controlling the third gold The hydrogen gas is moved from the group hydride heat exchanger to one of the fourth and fifth metal hydride heat exchangers, and the first and second metal hydrogen is fed from the other of the fourth and fifth metal hydride heat exchangers. The hydrogen gas is moved to the heat exchanger for hydride, the movement of hydrogen in the heat exchanger for second metal hydride is stopped, and the heat exchanger for second metal hydride is changed to → 1 metal hydride heat exchanger → 1st heat medium high temperature side heat exchange unit → 2nd
A first heat medium passage through which the first heat medium circulates is formed in the order of the metal hydride heat exchanger, and a third metal hydride heat exchanger → first heat medium low temperature side heat exchange unit → third By controlling the first step of forming the first heat medium passage through which the first heat medium circulates in the order of the metal hydride heat exchanger, the second heat medium passage switching device, and the hydrogen gas passage switching device, The hydrogen gas is moved from the heat exchanger for the second metal hydride to one of the heat exchangers for the fourth and fifth metal hydrides and the third to the third heat exchangers for the fourth and fifth metal hydrides. The hydrogen gas is moved to the heat exchanger for metal hydride, the movement of hydrogen in the heat exchanger for first metal hydride is stopped, and the heat exchanger for first metal hydride is changed by the first heat medium passage switching device. → Heat exchanger for third metal hydride → High temperature side heat exchange unit for first heat medium Knit → 1st
A first heat medium passage through which the first heat medium circulates is formed in the order of the metal hydride heat exchanger, and the second metal hydride heat exchanger → first heat medium low temperature side heat exchange unit → second By controlling the second step of forming the first heat medium passage in which the first heat medium circulates in the order of the metal hydride heat exchanger, the second heat medium passage switching device, and the hydrogen gas passage switching device, The hydrogen gas is moved from the heat exchanger for the first metal hydride to one of the heat exchangers for the fourth and fifth metal hydrides, and the second heat is transferred to the second heat exchanger for the fourth and fifth metal hydrides. The hydrogen gas is moved to the heat exchanger for metal hydride, the movement of hydrogen in the heat exchanger for third metal hydride is stopped, and the heat exchanger for third metal hydride is changed by the passage switching device for the first heat medium. Heat exchanger for second metal hydride → High temperature side heat exchange unit for first heat medium First heat medium is circulated in the order of the heat exchanger for the third metal hydride
A first heat medium is circulated in the order of a heat medium passage, a first metal hydride heat exchanger, a first heat medium low temperature side heat exchange unit, and a first metal hydride heat exchanger. A method for controlling a heat pump using a metal hydride, characterized in that the above first to third steps of the third step of forming a heat medium passage are sequentially repeated. 3. The transfer of hydrogen gas between the heat exchangers for metal hydrides is stopped between the first step, the second step, and the third step, and the passage for the first heat medium is The heat pump control method using a metal hydride according to claim 2, further comprising an intermediate step of holding the previous step as it is.