JPH0120346B2 - - 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 rapidly and exothermically absorb hydrogen to form metal hydrides, and that these metal hydrides reversibly and endothermically release hydrogen. The equilibrium decomposition pressure P of such a metal hydride is generally a function of temperature, and as shown in FIG. 1, the higher the temperature T, the greater the equilibrium decomposition pressure. Therefore, for example, if a metal hydride is built into two heat exchangers connected so that hydrogen can flow between them, and one is kept at a high temperature T _H and the other at a low temperature T _L , the heat exchange on the high temperature side is The metal hydride in the vessel emits hydrogen endothermically at the equilibrium decomposition pressure P _H.
Since the equilibrium decomposition pressure of the metal hydride in the heat exchanger on the low temperature side is P _L (<P _H ), the above hydrogen moves to the heat exchanger on the low temperature side due to this difference in equilibrium decomposition pressure, and this The metal hydride in the heat exchanger absorbs hydrogen exothermically. That is, heat is transported from the heat exchanger on the high temperature side to the heat exchanger on the low temperature side.

In addition, if the two heat exchangers mentioned above are connected so that hydrogen flows through a compressor, and one heat exchanger is depressurized while the other heat exchanger is pressurized with hydrogen, the metal hydride on the depressurized side can be Hydrogen is released endothermically, and the metal hydride on the pressurized side absorbs hydrogen exothermically. That is, heat is transported from the reduced pressure side to the increased pressure side. Therefore, for example, if the pressure reduction side is set to a lower temperature T _L
The pressure side is connected to a cooling load of high temperature T _H (＞
When connected to T _L ), heat is transported from the low temperature side to the high temperature side, so it functions as a heat pump.

However, in any of the above heat transport devices or heat pump devices, heat transport stops when all the hydrogen is released from one metal hydride, so in order to continue heat transport, the former device requires two Two heat exchangers must be alternately heated and cooled, and in the latter device two heat exchangers must be alternately pressurized and depressurized. That is, since heat transport is essentially a batch system, when the heat generated or absorbed by the metal hydride is extracted as output, the output is not stationary. If four or more heat exchangers are used, a phase difference is created between each heat exchanger, hydrogen is released and absorbed, and the output is taken out from each heat exchanger in sequence, it appears to be continuous. However, it requires a complicated control mechanism. Furthermore, in conventional devices, the calorific value or endothermic value of the metal hydride is consumed for heating or cooling the heat exchanger itself, or extra thermal energy is required.
They cannot escape various disadvantages. Furthermore, since the thermal conductivity of metal hydrides is generally low, a tube group with fins is often used as a heat exchanger, and as a result, the heat exchanger itself has a large heat capacity and poor heat transport efficiency.

The present invention was made in order to solve the various problems described above in conventional heat pump devices, and is a heat pump that eliminates the need for heating and cooling cycles of a heat exchanger and can continuously extract stable output. The purpose is to provide instructions on how to operate the device.

The method of operating the heat pump device of the present invention is to carry a high-pressure chamber and a low-pressure chamber partitioned by partition walls in a closed container, carry a metal hydride, and continuously reciprocate between the high-pressure chamber and the low-pressure chamber in the form of a rotating belt. It has a tape to be run, and a high-temperature heat medium and a low-temperature heat medium that can exchange heat with the tape in a high-pressure chamber and a low-pressure chamber, respectively, and hydrogen is supplied at high pressure to the high-pressure chamber to exothermically inject hydrogen into the metal hydride. At the same time, hydrogen is removed from the low pressure chamber, placed under low hydrogen pressure, hydrogen is released endothermically from the metal hydride, and heat is transferred from the low temperature heat medium to the high temperature heat medium. be.

The present invention will be explained below with reference to drawings showing examples.

FIG. 2 shows a very basic embodiment of the heat pump device used in the present invention, in which a closed container 1 is divided by a partition wall 2 into a low pressure chamber 3 and a high pressure chamber 4, and hydrogen is removed from the low pressure chamber. Meanwhile, hydrogen is supplied under pressure to the high pressure chamber. For example, as shown in the figure, two chambers are connected by a connecting pipe 5, and a compressor 6 is disposed in this pipe, and the compressor removes hydrogen from the low pressure chamber and supplies it under pressure to the high pressure chamber. Enter. Further, a heating roll 7 is disposed in the low pressure chamber, and a cooling roll 8 is disposed in the high pressure chamber, and these are thermally connected to a low temperature heat medium 9 and a high temperature heat medium 10 so as to be able to exchange heat, respectively. A tape carrying a metal hydride MH (hereinafter simply referred to as tape) is wound like an endless rotating belt between the heating roll and the cooling roll, and the tape is sealed airtight by an appropriate sealing means provided on the partition wall. It penetrates the partition wall and is driven to travel in a fixed direction while substantially maintaining the same.

The operation of this device will be explained based on FIG.
The tape exothermically absorbs hydrogen while being cooled to a temperature T _H by a high-temperature heating medium in a high-pressure chamber to which high-pressure hydrogen is supplied. That is, the exothermic reaction heat at this time is supplied to the high temperature heating medium via the cooling roll. The hydrogen-absorbed tape then enters an evacuated low-pressure chamber, where it is heated to a temperature T _L and endothermically releases hydrogen under a small metal hydride equilibrium decomposition pressure. The endothermic reaction heat at this time is supplied from a heating roll connected to a low-temperature heating medium. In this way, as the tape runs, heat is continuously transported from the low-temperature heat medium to the high-temperature heat medium, functioning as a heat pump.

To use this device for air conditioning, the low-temperature heat medium can be used as the heat source, that is, the indoor cooling load, and the high-temperature heat medium can be used as a cooler at atmospheric temperature. The indoor heating load may be used as a low-temperature heat source such as the atmosphere, groundwater, or waste heat.

Any method may be used to support the metal hydride on the tape as long as it does not inhibit the absorption and desorption of hydrogen from the metal hydride. or dispersed in a silicone rubber film.

The metal hydride used is not particularly limited, but for example, a hydride of LaNi ₅ is preferably used. In this case, if the low-temperature heating roll is 20°C in the low-pressure chamber, the metal hydride will release hydrogen when the hydrogen atmospheric pressure is lower than 1 atm, so if the hydrogen pressure is set at 7 atm or higher in the high-pressure chamber, Even if the high-temperature cooling roll is at 50°C, LaNi ₅ still absorbs hydrogen, so the heat generated at this time can be given to the high-temperature heating medium.

According to the method of operating a heat pump device of the present invention, as described above, the metal hydride is supported on the rotating belt-like tape and is continuously moved back and forth between the high pressure chamber and the low pressure chamber. Continuous operation provides continuous and stable heat output. Therefore, unlike conventional equipment using a heat exchanger filled with metal hydride, which requires switching the heat source to alternately heat and cool the heat exchanger, it is necessary to keep the heat source or heat medium constant at all times. Since it is only necessary to maintain the temperature at , there is no need for a complicated heat medium circuit or a control device for this, and the device configuration is significantly simplified.

In the present invention, tapes carrying metal hydrides having different equilibrium decomposition pressure characteristics can be arranged in parallel in multiple stages. FIG. 3 shows an embodiment in which the tapes are arranged in two stages. Similar to the embodiment shown in FIG. 2, the sealed container 1 is divided into a low pressure chamber 3 and a high pressure chamber 4 by a partition wall 2, and both chambers are connected by a connecting pipe 5. 6, the low pressure chamber is depressurized and hydrogen is supplied under pressure to the high pressure chamber. Inside the sealed container, two types of tapes carrying metal hydrides M ₁ H and M ₂ H with different equilibrium decomposition pressure characteristics were run in parallel, each passing through the partition wall between the high-pressure chamber and the low-pressure chamber. Go back and forth. The first tape carrying M ₁ H is placed in a low pressure chamber at a temperature T _L
The second tape is thermally connected to a high temperature heat transfer medium 10 at a temperature T _H in a high pressure chamber. Medium-temperature roll 11 that supports the first tape in the high-pressure chamber and medium-temperature roll 1 that supports the second tape in the low-pressure chamber.
2 are preferably thermally connected to enable heat exchange using a heat pump 13 or the like, and are maintained at approximately the same temperature T _M . Here, as shown in Figure 4, the equilibrium decomposition pressure characteristics of the metal hydrides are as follows: M ₂ H is higher than M ₁ H
The above temperature relationship is T _L < T _M < T _H .

This device will be explained based on FIG. For simplicity, it is assumed above that the medium temperature rolls 11 and 12 are at the same temperature, but there is no problem even if they are at different temperatures. Moreover, each medium temperature roll 11 and 12 may be connected to medium temperature heating medium 14 and 15, respectively.

First, in the low-pressure chamber, M ₁ H is heated by the low-temperature heating medium 9 at a temperature T _L , and is reduced to a pressure P _L by being depressurized by a compressor, and hydrogen is endothermically released in the state at point A. M ₁ H, which has released this hydrogen, enters the high pressure chamber as the tape runs, and hydrogen is supplied under pressure to this high pressure chamber by a compressor at a pressure of P _H , so M ₁ H is at a temperature of T _M Hydrogen is exothermically occluded in the state of point B while applying heat to the intermediate temperature heating medium 14 or while applying heat to the intermediate temperature roll 12. M ₁ H, which has absorbed hydrogen in this way, is sent to the low pressure chamber again.
Repeat the above cycle.

On the other hand, M ₂ H is heated to a temperature T _M in the low pressure chamber by being given heat from the medium temperature heating medium 15 or the medium temperature roll 12, and endothermically releases hydrogen at point C. This released hydrogen is again sent to the high pressure chamber by the compressor, and is exothermically occluded in M ₂ H at the pressure P _H in the state at point D. This reaction heat is generated by the high temperature roll 8
The high temperature heat medium 10 is extracted from the heat transfer medium 10. After all, according to this device, heat is taken in from the low temperature heat medium 9 at the temperature T _L and released to the high temperature heat medium 10 at the temperature T _H.

This device provides higher temperature heat output or lower temperature cold output with the same compressive power than the single tape arrangement shown in FIG.

The same applies when the tapes are arranged in three or more stages. Generally, as shown in Fig. 5, a number n of tapes supporting metal hydrides M ₁ H, M ₂ H, ..., M _o H, each having different equilibrium decomposition pressure characteristics, are placed in a sealed container 1. The tapes are run in parallel, and the first tape is connected in the low pressure chamber so as to be able to exchange heat with the low temperature heat medium at temperature T _L1 , and the
The ith tape is connected for heat exchange with a high temperature heat transfer medium having a temperature T _Ho , the i th (2 inch) tape has a temperature T Li in the low pressure chamber, and the i th (2 inch) tape has a temperature T _Li in the high pressure chamber. 1in-1)
has a temperature T _Hi , where the temperature relationship is T _Li
<T _Li+1 , T _Hi <T _Hi+1 , and T _Li <T _Hi . In addition, the equilibrium decomposition pressure characteristics of each metal hydride are M _i+1
H is selected so that it is in a higher temperature region than M _i H. However, to avoid the complication of using heating media of various different temperatures, M _i H tape (1in-1) in the high pressure chamber and M _{i +1} in the low pressure chamber are used.
H tape (1in-1) may be thermally connected to a common heating medium so that the temperature is approximately the same, or they may be connected by a heat pipe or the like. In this case, the temperature relationship is roughly T _L < T _H1 (=
T _L2 )＜…＜T _Hi (=T _Li+1 )＜T _Hi+1 (=T _Li+2 )＜…＜
T _Ho-1 (= T _Lo ) < T _H.

M _i H tape (1
FIG. 6 shows a cycle diagram when the M _i+1 H tape (1in-1) and the M i+1 H tape (1in-1) in the low pressure chamber are thermally connected to enable heat exchange. That is, as the number of tape arrays increases, higher temperature heat output can be obtained.

The above embodiment is a pressure-driven type that uses a compressor as a means to reduce the pressure in the low-pressure chamber and supply hydrogen under pressure to the high-pressure chamber, but a heat-driven type that uses a so-called thermal compressor instead of this compressor You can also. A thermally driven embodiment is shown in FIG.

Similarly to the above, in the closed container 1 having the low pressure chamber 3 and the high pressure chamber 4, the medium temperature roll 12 is placed in the low pressure chamber.
However, a high-temperature roll 8 is also disposed in the high-pressure chamber, and the medium-temperature roll 12 is thermally connected to a medium-temperature heating medium 15 and the high-temperature roll 8 is thermally connected to a high-temperature heating medium 10 so as to be able to exchange heat, respectively. A tape carrying a first metal hydride M ₁ H is run between the rolls. Therefore, as shown in Figure 8, by heating M ₁ H in a high pressure chamber with a high temperature heat medium at a temperature T _H ,
In the state at point A, hydrogen can be released endothermically at high pressure. M ₁ H then enters the low pressure chamber and is cooled to temperature T _M by medium temperature heating medium 15.
It stores hydrogen in the state of point D. Therefore, in the heat pump device of the present invention, hydrogen can be supplied under pressure and removed under reduced pressure by reciprocating the tape carrying M ₁ H between different temperatures. That is, it can function as a thermal compressor.

Therefore, a second tape carrying a second metal hydride M ₂ H having equilibrium decomposition pressure characteristics in a higher temperature region than the first metal hydride M ₁ H is run in parallel with the tape in a sealed container. . The second tape is supported by a low-temperature roll 7 in the low-pressure chamber, and by a medium-temperature roll 11 in the high-pressure chamber, and these low-temperature rolls 7 and medium-temperature rolls 11 are connected to a low-temperature heat medium 9 at a temperature T _L and a low-temperature heat medium 9 at a temperature T _M , respectively. It is thermally connected to the medium-temperature heat medium 14 for heat exchange. Here, the temperature relationship is T _L < T _M < T _H. The medium temperature rolls 8 and 7 may be thermally connected by a heat pipe or the like as described above.

According to this device, as shown in Fig. 8, M ₂ H in the high pressure chamber transfers the hydrogen released by M ₁
In this state, M 1 H absorbs heat while applying heat to the medium-temperature heat medium 14, and releases hydrogen while absorbing heat from the low-temperature heat medium 9 in the low-pressure chamber, and this hydrogen is absorbed by M ₁ H in the low-pressure chamber. That is, in this device, heat is transferred to the high temperature heating medium 10.
and the low-temperature heat medium 9 to the medium-temperature heat medium 14 and 15. Therefore, to use this device for air conditioning, use a low-temperature heat medium as the cooling load, use solar heat, boiler heat, or various waste heat sources as the high-temperature heat medium, and use water, air, etc. as the medium-temperature heat medium. good. Note that the second tapes may be arranged in multiple stages as shown in FIG.

To use the above-described heat pump device for heating, if air or water is used as the low-temperature heat source, the heat supplied from the high-temperature heat source and the heat supplied from the low-temperature heat source can be obtained as output from the medium-temperature heat medium.

Preferably, however, the operation of the M ₂ H tape is made to function as a thermal compressor and, by the cycle diagram shown in FIG. 9, as a heating device. In this case, the high-temperature heat medium 10 is used as a heating load for a room or the like, the medium-temperature heat medium is used as a medium-temperature heat source such as solar heat or waste heat, and a cooler such as air is used as a low-temperature heat medium. The flow of hydrogen is opposite to the direction indicated by the arrow in FIG. In the high-pressure chamber, M ₂ H receives heat from the intermediate temperature heating medium 14 and releases hydrogen endothermically, and this high-pressure hydrogen is
M ₁ H is absorbed exothermically. The exothermic reaction heat at this time is applied to the heating load 10 of high temperature T _H. M ₁ H that has stored hydrogen releases hydrogen in a low-pressure chamber, and the endothermic reaction heat at this time is supplied from a medium-temperature heating medium. This hydrogen is absorbed by M ₂ H in the low-pressure chamber, and the exothermic reaction heat at this time is given to the low-temperature heating medium. In this case too
It will be clear that the M ₂ H tapes may be arranged in multiple stages.

Next, for example, in the cooling system,
The tape is heated in a high-pressure chamber and then cooled in a low-pressure chamber. In order to more effectively heat and cool the tape as it runs, a rotating belt-shaped tape is used as shown in Figure 7. For example, the tape in the high-pressure chamber and the tape in the low-pressure chamber can be thermally connected to each other by a heat pipe 16 or the like so that they can exchange heat, and sensible heat can be exchanged. The tapes are preferably thermally connected immediately after entering the high pressure chamber and the low pressure chamber, respectively. Therefore, for simplicity, tape
If M ₁ H enters the low pressure chamber at temperature T _H and enters the high pressure chamber at temperature T _M , the tape entering the low pressure chamber due to the heat exchange between these two tapes will have a temperature between T _H and T _M. At the same time, the tape entering the high pressure chamber is preheated to a temperature intermediate between T _M and T _H. For example, if the tape entering the high-pressure chamber is preheated to temperature T _G (Figure 8), heating the tape in the high-pressure chamber only needs to increase its temperature from T _G to T _H ; The required amount of heat to be supplied can be reduced. Similarly,
If the M ₂ H tape is thermally connected by a heat pipe 17 or the like and the tape entering the low pressure chamber is pre-cooled to a temperature T _K , then the amount of cooling energy required to cool the tape itself from the temperature T _M to T _L is large. Output cold heat can be obtained.

[Brief explanation of drawings]

Fig. 1 is a graph showing the temperature characteristics of the equilibrium decomposition pressure of metal hydrides, Fig. 2 is a schematic diagram showing one embodiment of the heat pump device used in the present invention, and Fig. 3 is a schematic diagram showing another embodiment. Fig. 4 is a cycle diagram showing the operation of the device shown in Fig. 3, Fig. 5 is a schematic diagram showing an embodiment similar to Fig. 3, and Fig. 6 is a cycle diagram showing the operation of the device shown in Fig. 5. FIG. 7 is a schematic diagram showing yet another embodiment, and FIGS. 8 and 9 are cycle diagrams showing the operation of the apparatus of FIG. 7. 1... Sealed container, 2... Partition wall, 3... Low pressure chamber,
4...High pressure chamber, 5...Connecting pipe, 6...Compressor, 7
... low temperature roll, 8 ... high temperature roll, 9 ... low temperature heating medium, 10 ... high temperature heating medium, 11, 12 ... medium temperature roll, 14, 15 ... medium temperature heating medium, MH ... metal hydride.

Claims (1)

[Claims] 1. A high-pressure chamber and a low-pressure chamber defined by partition walls in a closed container, carrying a metal hydride, and continuously reciprocating between the high-pressure chamber and the low-pressure chamber in the form of a rotating belt. It has a tape and a high-temperature heat medium and a low-temperature heat medium that can exchange heat with the tape in a high-pressure chamber and a low-pressure chamber, respectively, and supplies hydrogen at high pressure to the high-pressure chamber to exothermically absorb hydrogen into the metal hydride. In addition, a method for operating a heat pump device, characterized in that hydrogen is removed from a low-pressure chamber, the metal hydride is placed under low hydrogen pressure, hydrogen is endothermically released from a metal hydride, and heat is transferred from a low-temperature heat medium to a high-temperature heat medium. . 2. Claim 1, characterized in that the high pressure chamber and the low pressure chamber are connected by a connecting pipe equipped with a compressor, and the compressor removes hydrogen from the low pressure chamber and supplies it to the high pressure chamber. How to operate the heat pump device described in Section 1. 3. Several n tapes carrying metal hydrides each having different equilibrium decomposition pressure characteristics are run in parallel, and the first tape is connected in a low-pressure chamber so as to be able to exchange heat with a low-temperature heat medium at a temperature T _L , The n-th tape placed in the high-pressure chamber is connected so as to be able to exchange heat with a high-temperature heating medium at a temperature T _H , and the i-th tape (2≦i≦n) in the low-pressure chamber
T _Li and the i-th (1≦i≦
n-1) has a temperature T _Hi , where T _Li <
T _Li+1 , T _Hi <T _Hi+1 , T _Li <T _Hi , and the (i-th
+1) The equilibrium decomposition pressure characteristics of the metal hydride of the tape (1≦i≦n−1) are the same as those of the ith (1≦i≦n
2. The method of operating a heat pump device according to claim 1, wherein the temperature is higher than the equilibrium decomposition pressure characteristic of the metal hydride of the tape in item 1). 4 i-th in hyperbaric chamber (1≦i≦n-1)
tape and the (i+1)th (1)th tape in the low pressure chamber.
4. The method of operating a heat pump device according to claim 3, wherein the heat pump device is thermally connected to the tape of ≦i≦n-1 so as to be able to exchange heat. 5 Running a second tape carrying a second metal hydride having equilibrium decomposition pressure characteristics in a higher temperature region than the first metal hydride in parallel with the first tape carrying the metal hydride; Along with letting
The low pressure chamber of this second tape has a higher temperature than the low temperature heat medium, the high pressure chamber has a higher temperature than the high temperature heat medium, the high pressure chamber has a higher temperature than the low pressure chamber, and the high pressure chamber has a higher temperature than the high temperature heat medium. hydrogen is endothermically released from the first metal hydride, hydrogen is supplied to the first metal hydride at high pressure, hydrogen is exothermically absorbed into the second metal hydride in a low pressure chamber, and the first metal hydride is The method of operating a heat pump device according to claim 1, characterized in that hydrogen is endothermically released from the hydride. 6 Running a second tape carrying a second metal hydride having equilibrium decomposition pressure characteristics in a lower temperature region than the first metal hydride in parallel with the first tape carrying the metal hydride; Along with letting
The second tape has a lower temperature in the low pressure chamber than the low temperature heating medium, a lower temperature in the high pressure chamber than the high temperature heating medium, and a higher temperature in the high pressure chamber than the low pressure chamber. hydrogen is endothermically released from the first metal hydride, hydrogen is supplied to the first metal hydride at high pressure, hydrogen is exothermically absorbed into the second metal hydride in a low pressure chamber, and the first metal hydride is The method of operating a heat pump device according to claim 1, characterized in that hydrogen is endothermically released from the hydride.