JPS6329182B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method of operating a heat pump device,
More specifically, the present invention relates to a method of operating a heat pump device using metal hydrides.

It is known that certain metals and alloys exothermically absorb hydrogen 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 metal hydrides.
As shown in Figure 1, the conventional heat pump device
A first metal hydride M ₁ H is filled in the first closed container 1, and a second metal hydride M ₂ H having a higher equilibrium decomposition pressure P than M ₁ H in the operating temperature range is filled in the second closed container 2. At the same time, the first and second
The first sealed container has a high temperature heating medium 5 at a temperature T _H , and the second sealed container has a temperature T _L.
A low temperature heat medium 6 is connected to the first and second closed containers, and a medium temperature heat medium 7 having a temperature T _M is switchably connected to the first and second closed containers.

The operation of this device will be explained using the cycle diagram shown in FIG. For example, when obtaining cold output,
Connect M ₂ H to a medium-temperature heating medium at temperature T _M , such as the atmosphere (point B), and connect M ₁ H to a high-temperature heating medium, which is a driving heat source, to heat it to temperature T _H , and bring M ₁ H into equilibrium. Decomposition pressure _M2H
(point A), hydrogen is endothermically released from M ₁ H using the difference in equilibrium decomposition pressure, and this hydrogen is exothermically occluded by M ₂ H. Then M ₁ H
is connected to a medium-temperature heating medium and cooled to a temperature T _M to make its equilibrium decomposition pressure lower than that of M ₂ H (point D),
Using the difference in equilibrium decomposition pressure, hydrogen is endothermically released from M ₂ H, and this hydrogen is exothermically stored in M ₁ H. The endothermic reaction of M ₂ H in this hydrogen transfer process is obtained as cold heat at a temperature T _L from the low-temperature refrigerant connected to M ₂ H (point C), and the cycle is completed.
To obtain thermal output, in the above cycle, a high temperature heating medium and a low temperature heating medium are used as driving heat sources, and M ₂ H
The exothermic reactions in the hydrogen absorption reaction of (point B) and the hydrogen absorption reaction of M ₁ H (point D) are utilized.

However, in the above-described heat pump device, when the heat source temperature fluctuates easily, such as solar heat or waste heat, the device does not operate when the heat source does not reach a predetermined temperature. For example, when obtaining the cold output described above, the temperature of the driving heat source decreases to T _E as shown in Figure 2, and as a result, the equilibrium decomposition pressure of M ₁ H becomes equal to the decomposition equilibrium of M ₂ H at point B. When the pressure is less than the pressure, hydrogen transfer from M ₁ H to M ₂ H cannot occur. Similarly, when obtaining thermal output, for example, when the temperature of the low-temperature driven heat source changes to T _F and the equilibrium decomposition pressure of M ₂ H becomes lower than the equilibrium decomposition pressure of _{M 1} H at point D, the Hydrogen transfer to M ₁ H cannot occur. Further, the above-described heat pump device requires a high temperature heat medium, a low temperature heat medium, or a plurality of drive heat sources as a driving heat source, and in general, the temperature and supply of the heat medium are unstable.

Furthermore, in conventional heat pump devices, the third
For example, when obtaining thermal output from the cycle shown in the figure, the following problems arise. That is, M ₁ H is heated to a temperature T _M by a medium-temperature heating medium such as solar heat, and M ₂ H
While cooling M 1 H to a temperature T _L with a low-temperature heating medium such as the atmosphere, hydrogen is released from M ₁ H (point A).
M ₂ H is occluded (point B), then hydrogen is released from M ₂ H by heating M ₂ H to temperature T _M with a medium temperature heating medium (point C), and hydrogen is occluded by M ₁ H. (point D), when obtaining a thermal output at a temperature T _H from the heat generated by M ₁ H, if the temperature of the medium-temperature heating medium serving as the driving heat source is low, hydrogen transfer will not occur and a thermal output at a temperature T _H will be obtained. I can't. Moreover, in order to obtain thermal output, a contradictory condition is required: the temperature of the low-temperature heating medium, which is the low-temperature drive heat source, must be lower, and the heat loss during heating and cooling of the metal hydride must be large. There are some unavoidable drawbacks.

The present invention has been made in view of the above, and includes:
It is an object of the present invention to provide a method for operating a metal hydride heat pump device that prevents heat loss due to heating and cooling of metal hydride without relying on an unstable driving heat source.

The method of operating a heat pump device of the present invention includes the first
a second sealed container filled with a second metal hydride having a higher equilibrium decomposition pressure than the first metal hydride in the operating temperature range; Hydrogen can be transferred from the second closed container to the first closed container by the pressure difference between the equilibrium decomposition pressure of the second metal hydride and the second metal hydride, and
A communication pipe having a drive controllable compressor capable of forcibly transferring hydrogen from the first closed container to the second closed container against the opposite pressure of the equilibrium decomposition pressure of the first and second metal hydrides. In a heat pump device configured by connecting a medium-temperature or low-temperature heat medium to the first and second closed containers in a switchable manner for heat exchange, the second closed container is connected to the low-temperature heat medium. The first closed container is connected to a medium temperature heating medium, and the second metal hydride is endothermically released from hydrogen by the difference in the equilibrium decomposition pressures of the first and second metal hydrides. Hydrogen is exothermically occluded in a first metal hydride, then the first metal hydride is connected to a low temperature heating medium, the second metal hydride is connected to an intermediate temperature heating medium, and a second metal hydride is connected to a medium temperature heating medium. Hydrogen is forcibly released endothermically from the first metal hydride against the opposite pressure of the equilibrium decomposition pressure of the first metal hydride and the second metal hydride, and this hydrogen is exothermically released into the second metal hydride. It is characterized by being occluded.

The present invention will be described below based on drawings showing examples.

FIG. 4 shows an embodiment of the heat pump device used in the present invention, in which the first sealed container 1 and the second sealed container 2 are filled with M ₁ H and M ₂ H, respectively, and the space between the containers is The first valve is equipped with _{a valve 3 such as a solenoid valve that can be opened and closed so as to move hydrogen from the second closed container to the first closed container based on the pressure difference between the equilibrium decomposition pressures of M 1 H} and M 2 H. a communicating pipe 4,
A compressor 8 equipped with a compressor 8 that can be driven and controlled to forcibly move hydrogen from the first closed container to the second closed container against the reverse pressure of the equilibrium decomposition pressure of M ₁ H and M ₂ H. They are communicated with each other by two communication pipes 9. Note that the valve 3 and the compressor 8 may be provided in the same communication pipe. Further, both containers are connected to a medium-temperature heat medium 6 and a low-temperature heat medium 7 in a switchable manner so as to exchange heat with each other.

Next, the operation of the above device will be explained with reference to the cycle diagram shown in FIG. First, by connecting M ₁ H to a medium temperature heating medium and connecting M ₂ H to a low temperature heating medium, the equilibrium decomposition pressure of M ₂ H is made higher than that of M ₁ H.
A pressure difference of the equilibrium decomposition pressure is created between M ₁ H and M ₂ H, and _{the valve is opened to release hydrogen endothermically from M 2 H} (point A). (Point B). The valves are then closed and M ₁ H is connected to the low temperature heating medium (point C) and M ₂ H is connected to the medium temperature heating medium (point D). In this case, the equilibrium decomposition pressure of M ₁ H is lower than that of M ₂ H, so drive the compressor and force
Hydrogen is released endothermically from M ₁ H, and this hydrogen is
It is exothermically occluded by M ₂ H. Next, the cycle is completed by again connecting M ₁ H to the medium temperature heating medium and M ₂ H to the low temperature heating medium.

In the above cycle, if air is used as the medium-temperature heating medium and formed in the air cooler, cold heat is given to the low-temperature heating medium at points A and C, and air is used as the low-temperature heating medium and formed in the air heater. Heat is applied to the medium-temperature heating medium at points B and D, so that cold or heat output can be obtained twice during one cycle. Furthermore, it is also possible to obtain cold output at points A and C, and at the same time obtain thermal output at points B and D by the cycle of FIG.

Note that the heating medium is not limited to one type; for example, when obtaining cold output, if a heating medium with a temperature T _{S lower than the temperature T M can} be used as a medium-temperature heating medium,
As shown in Figure 6, M ₂ H is a low-temperature heating medium and a temperature T _S
By switchably connecting to the medium temperature heating medium of
Forced hydrogen transfer from M ₁ H to M ₂ H (point C
The amount of work of the compressor from point D) to point D) can be reduced. In addition, when obtaining thermal output, the temperature
When a heating medium with a temperature T _S higher than the low temperature heating medium T _L can be used as a low temperature heating medium, as shown in Fig. 7,
By connecting M ₁ H switchably to a medium-temperature heating medium and a low-temperature heating medium of temperature T _S , it is possible to convert M ₁ H to
The amount of work of the compressor when forcibly transferring hydrogen to M ₂ H can be reduced. In addition, as shown in Figure 8, if M ₂ H is connected to a medium-temperature heating medium and a low-temperature heating medium with a temperature T _S , it can be used at a higher temperature.
Since hydrogen can be transferred from M ₂ H to M ₁ H (from point A to point B), thermal output can be obtained at a higher temperature in M ₁ H.

In addition, in Fig. 6, the cold output is obtained at points A and C, and the thermal output is obtained at point B.
In the figure, it is also possible to obtain thermal output at points B and D and cold output at point A, or to obtain thermal output at points B and D and cold output at point C in FIG.

As described above, in the operating method of the heat pump device of the present invention, as shown in the cycle diagrams of FIGS. By doing so, it is possible to obtain cold or heat output, and then, in the hydrogen transfer from point A to point B, cold or heat can be obtained without using any heat source.

As described above, according to the operating method of the present invention,
Hydrogen transfer from M ₂ H to M ₁ H is performed by a pressure difference between their equilibrium decomposition pressures, and hydrogen transfer from M ₁ H to M ₂ H is performed by a compressor against the opposite pressure of their equilibrium decomposition pressures. Unlike conventional heat pump devices, the device can be operated without relying on an unstable driving heat source, and furthermore,
Output can be obtained two or more times in succession in one cycle.

[Brief explanation of the drawing]

Fig. 1 shows an example of a conventional metal hydride heat pump device, Figs. 2 and 3 are cycle diagrams for explaining its operation, and Fig. 4 shows an example of the heat pump device used in the present invention. , FIG. 5 is a cycle diagram for explaining its operation, and FIGS. 6 to 8 are cycle diagrams when another heat source is used in combination. DESCRIPTION OF SYMBOLS 1...First airtight container, 2...Second airtight container, 3...Valve, 4...First communication pipe, 5...High temperature heat medium, 6...Medium temperature heat medium, 7...Low temperature Heat medium, 8...
Compressor, 9...second communication pipe.

Claims (1)

[Claims] 1. A first closed container filled with a first metal hydride, and a second closed container filled with a second metal hydride that has a higher equilibrium decomposition pressure than the first metal hydride in the operating temperature range. , hydrogen can be transferred from the second sealed container to the first sealed container by the pressure difference between the equilibrium decomposition pressures of the first and second metal hydrides, and the equilibrium decomposition pressure of the first and second metal hydrides is Forced to move from the first closed container to the second container against the reverse pressure of the decomposition pressure.
a communication pipe having a drive-controllable compressor capable of transferring hydrogen to a closed container of the first and second
In the heat pump device, the second sealed container is connected to the low-temperature heating medium, and the first sealed container is connected to the medium-temperature or low-temperature heating medium for heat exchange. is connected to a heating medium, the second metal hydride is endothermically released hydrogen due to the pressure difference between the equilibrium decomposition pressures of the first and second metal hydrides, and this hydrogen is transferred to the first metal hydride. exothermically occluding the first metal hydride and then connecting the first metal hydride to a low temperature heating medium and connecting the second metal hydride to a medium temperature heating medium so that the first and second metal hydrides are separated. A heat pump device characterized in that hydrogen is forcibly released endothermically from a first metal hydride against the opposite pressure of the equilibrium decomposition pressure, and this hydrogen is exothermically occluded in a second metal hydride. How to drive.