JPS634112B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to metal hydride devices. It is known that certain metals and alloys absorb hydrogen exothermically to form metal hydrides, and that these metal hydrides reversibly release hydrogen.
In recent years, various metal hydride devices such as heat pumps that utilize the characteristics of metal hydrides have been proposed. Conventionally, a first metal hydride MH1 and a second metal hydride having different equilibrium decomposition pressures are used.
In the case of a so-called four-cylinder metal hydride device, MH2 is filled in a closed container that can exchange heat with a heating medium, and the containers are communicated so that hydrogen can move between them to form a working pair. constitutes a metal hydride device by providing two pairs of the above working pairs. The operation of such a metal hydride device will be explained based on the cycle diagram shown in FIG. 1, with respect to the case where the cold output is obtained through a so-called clockwise cycle. In the drawing, the horizontal axis shows the reciprocal of absolute temperature,
The vertical axis shows the logarithm of the equilibrium decomposition pressure of the metal hydride.
Initially, it is assumed that MH1 is in a state in which it has sufficiently absorbed hydrogen (point D), and MH2 is in a state in which it has sufficiently released hydrogen (point C). First, MH1, which has a high equilibrium decomposition pressure in the operating temperature range, is heated by a high-temperature driven heat source at temperature TH, and MH1, which has a low equilibrium decomposition pressure,
When 2 is connected to a medium-temperature heating medium at a temperature TM, such as the outside air, MH1 endothermically releases hydrogen (point A), and MH2 exothermically occludes this hydrogen (B). After the hydrogen transfer is completed, MH1 is switched to a medium-temperature heating medium and connected, and MH2 is switched to and connected to a low-temperature heating medium of temperature TL for cooling loads, such as chilled water, and MH2 endothermically releases hydrogen. (Point C),
MH1 absorbs this hydrogen exothermically (point D).
Here, a cold output can be obtained in the low-temperature heating medium (point C), and a thermal output can be obtained in the medium-temperature heating medium (points B and D) as required. Once again, connect MH1 to the high temperature driving heat source and connect MH2 to the medium temperature heat transfer medium to start a new cycle. Therefore, by causing another working pair to perform the same cycle as above with a half-cycle delay, the cooling output associated with hydrogen release from MH2 can be obtained alternately from each working pair, and can be used, for example, for cooling. Also,
The thermal output can be used, for example, to heat hot water. However, in conventional metal hydride equipment that uses multiple pairs of the same working pairs consisting of two types of metal hydrides with different equilibrium decomposition pressures,
The temperature of the driving heat source is fixed in advance depending on the type of MH1 and MH2, so for example, an expensive first high-temperature heat source such as city gas, and an inexpensive or free second heat source such as solar heat or waste heat. Even if two or more types of heat sources with different temperatures can be used, such as a high-temperature heat source, only one of the heat sources must be used as the driving heat source depending on the preset operating temperature. In particular, when a low-cost or free heat source cannot be used as a high-temperature heat source, the coefficient of performance of the device is low and the thermal economy is poor. The present invention was made to solve these problems, and it uses a plurality of heat sources at different temperatures as driving heat sources at the same time, and outputs by varying the amount of metal hydride used depending on the working pair. The object of the present invention is to provide a metal hydride device that is highly economical in heat source utilization and has a high coefficient of performance. The first metal hydride device according to the present invention uses three types of metal hydrides that have different equilibrium decomposition pressures in the operating temperature range, and has two sealed containers filled with two types of metal hydrides that have different equilibrium decomposition pressures. They communicate with each other to form a working pair so that hydrogen can move, and at least two working pairs are provided, the first having a lower equilibrium decomposition pressure.
A metal hydride is filled into one sealed container of the first working pair, and a second metal hydride, which has the next lowest equilibrium decomposition pressure, is filled into one sealed container of the second working pair, and the equilibrium decomposition pressure is A third metal hydride with a higher temperature is charged into the remaining closed containers of the first and second working pairs, and the metal hydride charge of the working pairs driven by the higher temperature driving heat source is replaced by a lower temperature driving heat source. It is characterized in that the amount of metal hydride charged is greater than that of the working pair driven by a heat source. EMBODIMENT OF THE INVENTION The 1st metal hydride apparatus of this invention is demonstrated based on the drawing which shows an Example below. Figure 2 shows three types of metal hydrides, MH1, MH2, and
An example of the first metal hydride apparatus of the present invention using MH3 is shown, in which MH1 with the lowest equilibrium decomposition pressure and MH2 with the next lowest equilibrium decomposition pressure are respectively filled in closed containers 1 and 3 forming a heat exchanger. MH3 having a high decomposition pressure is filled in closed containers 2 and 4 forming a heat exchanger, and the containers 1 and 2 are communicated with each other through a communication pipe 9 so that hydrogen can move, forming a first working pair. Similarly, containers 3 and 4 are also communicated by a communication tube 10 to form a second working pair. Each communication pipe is provided with control valves 11 and 12 such as electromagnetic valves, and each communication pipe is opened and closed according to a cycle described later. Further, the container 1 is a first driving heat source 5 with a high temperature TH1.
and temperature TM are connected to a medium-temperature heating medium 6 through pipes 13 and 14, respectively, in a heat exchangeable and switchable manner, and the container 3 is connected to a medium-temperature heating medium 6 with a temperature TM, which is different from the first driving heat source.
It is connected to the second driving heat source 7 of TH2 (<TH1) and the intermediate temperature heat medium 6 through pipes 15 and 16, respectively, so that heat exchange and switching is possible. On the other hand, the first
In the working pair, the container 2 filled with MH3 having a high equilibrium decomposition pressure is connected via pipes 17 and 18 to a low-temperature heat medium 8 and a medium-temperature heat medium 6, respectively, at a temperature TL in a heat exchangeable and switchable manner. In the second working pair, the container 4 filled with MH3 is also connected via lines 19 and 20 to the low-temperature heating medium 8 and the medium-temperature heating medium 6, respectively, in a heat exchangeable and switchable manner. The connection between each container and the heat source or heating medium is switched by a control valve such as a solenoid valve (not shown). The device is a four-cylinder device with two working pairs. The operation of the above device will be explained with reference to the cycle diagram shown in FIG. In addition, in FIG. 2, a single medium-temperature heating medium 6 is shown, and the containers 1, 2, 3, and 4 are all connected to this single medium-temperature heating medium,
There is no need for a single intermediate temperature heating medium; for example,
In the first working pair, vessel 1 is connected to a medium-temperature heating medium at temperature TM1 and vessel 2 is connected to a temperature different from TM1.
It is connected to the intermediate temperature heating medium of TM2, and the second
In the working pair, vessels 3 and 4 are both at temperature TM2.
It may be connected to a medium temperature heating medium. FIG. 3 shows a cycle diagram in which each vessel is thus connected to a respective intermediate temperature heating medium. First, in the first working pair, vessel 1 is connected to a first high-temperature driving heat source to heat MH1 to temperature TH1, and vessel 2 is connected to a medium-temperature heating medium to heat MH3 to temperature TH1.
When maintained at TM2, MH1 emits hydrogen endothermically (point A), this hydrogen reaches vessel 2 via communicating pipe 9, and MH3 absorbs it exothermically (point B).
At the same time, in the second working pair, the container 3 is
TM2 is connected to a medium-temperature heating medium, and the container 4 is connected to a low-temperature heating medium at a temperature TL, and hydrogen is endothermically released from MH3 (point C), which reaches the container 3 through the communication pipe 10. If the temperature is increased and MH2 is exothermically occluded (point H), cold output can be obtained in the low temperature heat medium (point C). This cold output can be used for cooling, for example. Further, the thermal output due to hydrogen storage in MH3 (point B) and the thermal output due to hydrogen storage in MH2 (point H) can be used, for example, for hot water supply, as needed. Then, after the hydrogen transfer is completed in each working pair, in the first working pair, the vessel 1 is heated to a temperature TM1.
When connected to a medium-temperature heating medium and connecting container 2 to a low-temperature heating medium, MH3 releases hydrogen endothermically (point C) due to the pressure difference between the equilibrium decomposition pressures of MH1 and MH3 in the container. MH1 absorbs hydrogen exothermically (point D). Therefore, cold output can be obtained in the low-temperature heating medium (point C) due to heat absorption due to hydrogen release in MH3, and thermal output can be obtained in the medium-temperature heating medium (point D) due to heat generation due to hydrogen absorption in MH1. Obtainable. The cold output can be used, for example, for cooling, and the thermal output can be used, for example, for heating. At the same time, in the second working pair, the container 3 is
When MH2 is heated to temperature TH2 by connecting it to a high-temperature driving heat source of MH3 is exothermically occluded (point B). If the heat generated by the hydrogen absorption of MH3 is also required, it can be obtained as thermal output in the intermediate temperature heating medium (point B). The clockwise cycle is thus completed and a new cycle begins again by connecting each vessel to its original heat source or medium. As described above, according to the first metal hydride device of the present invention, it is possible to obtain cold output and/or thermal output by using two types of high-temperature heat sources having different temperatures. In addition, in the present invention, hydrogen transfer from MH1 to MH3 (A → B) is completed in the first working pair, and hydrogen transfer from MH3 to MH2 (C → H) is completed in the second working pair. When, temperature TH
Heat exchange is performed by circulating an appropriate heating medium between MH1 at temperature TM2 and MH2 at temperature TM2 through pipe 21,
Preheating MH2 to around the intermediate temperature between TH1 and TM2 is thermoeconomically advantageous because the heat supply from the drive heat source for heating MH2 to temperature TH2 in the next step can be reduced. At the same time, MH1
Since it is also possible to pre-cool the air, the efficiency of acquiring cold output is also increased. Similarly, for metal hydrides with high equilibrium decomposition pressure, MH3 at temperature TM2 and MH3 at temperature TL
It is thermoeconomically advantageous to circulate an appropriate heat medium between the MH3 and the MH3 through the pipe line 22 to perform heat exchange, and to preheat or precool each MH3 in preparation for the next step. Also, in the first working pair, from MH3 to MH1
The hydrogen transfer from MH2 to MH3 (E→D) is completed and the hydrogen transfer from MH2 to MH3 (E→
When B) is completed, heat is exchanged between MH2 at temperature TH2 and MH1 at temperature TM1, and
It is advantageous to preheat or precool the respective metal hydride by exchanging heat between MH3 at temperature TM2 and MH3 at temperature TL. In the device and cycle described above,
LaNi _4.75 Al _0.25 as MH1, as MH2
When using LaNi _4.85 Al _0.15 or LaNi _5.4 as MH3, the temperatures of the heat source and heat medium can be set approximately as follows. Input TH1=100℃ (first high temperature driving heat source) TH2=80℃ (second high temperature driving heat source) Output TL1=10℃ (cold output) TH1=45℃ (thermal output) TH2=30℃ (atmospheric temperature, Therefore, it is possible to obtain a cooling output of about 10°C and a heating output of about 45°C, and it can be suitably used in an air-conditioning hot water supply system. Here, in the device of the present invention, high temperature TH1
The amount of metal hydride charged into the first working pair driven by the first driving heat source of TH2 is
The amount of metal hydride charged into the second working pair driven by the driving heat source of In this way, not only can two types of high-temperature driving heat sources with different temperatures be used effectively, but also the thermal economy of the device can be improved, and at the same time, the coefficient of performance of the device can be increased. The conditions will be set as follows and will be explained with specific numbers. In a 4-cylinder type device, the total amount of metal hydride used in the device is 40 kg, and each working pair performs 3 cycles per hour, and when hydrogen transfer is completed between containers in each working pair, first As explained above, the recovery rate when recovering sensible heat is set to 0.4. In addition, the heat of reaction when 1 mole of hydrogen is released and stored in each metal hydride listed above is as follows: Hydrogen release MH1: 8.2 Kcal MH2: 7.8 MH3: 7.6 Hydrogen storage MH1: 8.0 14 MH2: 7.6 MH3: 7.4, and once Regarding the hydrogen transfer, 1 mole of metal hydride releases or absorbs 4.2 moles of hydrogen. Under these conditions, as a comparative example, the case where the amount of metal hydride filled in each working pair is the same as in the conventional case, and according to the present invention, As an example, the required inputs, the obtained output, and the coefficient of performance are shown in the table, taking as an example the case where the amount of metal hydride charged into the first working pair is larger than that of the other working pairs. Clearly, embodiments of the present invention improve the coefficient of performance of the device. Next, the second metal hydride device of the present invention uses three types of metal hydrides with different equilibrium decomposition pressures in the operating temperature range, and uses two types of metal hydrides filled with two types of metal hydrides with different equilibrium decomposition pressures. Closed containers are communicated so that hydrogen can move to form working pairs, and at least two working pairs are provided, and a first metal hydride having a high equilibrium decomposition pressure is placed in the sealed container of one of the first working pairs.

[Table] The second metal hydride with the next highest equilibrium decomposition pressure is charged into one closed container of the second working pair, and the third metal hydride with the lowest equilibrium decomposition pressure is charged with the second metal hydride having the next highest equilibrium decomposition pressure. and fill the remaining closed container of the second working pair, and fill the metal hydride charge of the working pair driven by the higher temperature driving heat source with the metal hydride charge of the working pair driven by the lower temperature driving heat source. It is characterized by having a larger amount than the hydride filling amount. This device is shown in FIG.
and 4 respectively MH3, MH1, MH3 and
The structure is filled with MH2, and the connections of the heat source and heat medium are the same as in FIG. Figure 4 shows a clockwise cycle of such a metal hydride device, with the first cycle consisting of MH1 and MH3.
The working pair performs a cycle from point A→B→C→D by the high temperature first driving heat source at temperature TH1, and the temperature
Give the cold output of TL (point C) and the thermal output of temperature TM1 (point D). The thermal output of TH1 accompanying the hydrogen transfer from MH3 to MH1 can be effectively used as needed, but it may also be released into the atmosphere at a temperature of TM2 (<TM1), for example. Further, the second working pair consisting of MH3 and MH2 performs a cycle from point E→F→G→H using the high temperature second drive heat source at temperature MH2, and provides a cold output at temperature TL. M.H.
The thermal output (points F and H) at temperature TM2 due to hydrogen absorption in step 3 can be effectively used as needed as described above, but may also be released outside the system. In this way, the cooling output at temperature TL is used for cooling, and the temperature
The thermal output in TM1 can be used for heating and hot water supply. Since the heat balance is the same in this device as in the first device, it is clear that the coefficient of performance of the device is similarly improved. Further, the third device of the present invention uses four types of metal hydrides with different equilibrium decomposition pressures, and uses four types of metal hydrides with different equilibrium decomposition pressures in the operating temperature range, and uses two types of metal hydrides with different equilibrium decomposition pressures. Two sealed containers filled with metal hydride are connected to each other so that hydrogen can move to form a working pair, and at least two pairs of these working pairs are provided, with the first metal hydride having the lowest equilibrium decomposition pressure being the first. One closed container of the first working pair is filled, a second metal hydride having the next lowest equilibrium decomposition pressure is filled into one of the closed containers of the second working pair, and a third metal hydride having the highest equilibrium decomposition pressure is filled. The metal hydride is filled into the remaining closed container of the first or second working pair, and the metal hydride with the next highest equilibrium decomposition pressure is filled into the remaining closed container of the second or first working pair, and at a higher temperature. It is characterized in that the amount of metal hydride filling in the working pair driven by the driving heat source is greater than the amount of metal hydride filling in the working pair driven by the driving heat source at a lower temperature. A cycle diagram as an example of the operation of this device is shown in FIG. The illustrated apparatus has containers 1, 2, 3 and 4 with MH1, MH3 and MH2 in FIG.
and MH4, respectively, and the connections with the heat source and heat medium are the same as those shown in FIG. Also, the cycles of the first and second actuation pairs and the resulting outputs are the same as in FIG. 3, and therefore the coefficient of performance of the device is similarly improved. In addition, in Figure 5, the hydrogen transfer (point C'→D') is shown by the dashed arrow.
It will also be readily understood that the thermal output of TM2 is obtained from four points: points B, F, H, and D'. According to the metal hydride device of the present invention, as described above, it is possible to effectively utilize two or more drive heat sources with different temperatures at the same time to obtain thermal output and/or cold output, and also to obtain higher temperature output. By making the metal hydride loading of the working pair driven by the driving heat source higher than the metal hydride loading of the working pair driven by the cooler driving heat source, the coefficient of performance of the device is increased. can be increased.

[Brief explanation of the drawing]

Fig. 1 is a cycle diagram showing the operation of a conventional metal hydride, Fig. 2 is a circuit configuration diagram showing an embodiment of the metal hydride device of the present invention, and Figs. FIG. 3 is a cycle diagram showing an example of the operation of the device of the invention. 1, 2, 3, 4...Airtight container, 5, 6, 7, 8,
23, 24, 25, 26, 27...heating medium or heating medium,
9,10...Communication pipe, 11,12...Control valve, 13,
14, 15, 16, 17, 18, 19, 20, 2
1, 22, 28, 29, 30, 31...Pipeline, MH
1, MH2, MH3, MH4...metal hydride.

Claims (1)

[Claims] 1. 3. Different equilibrium decomposition pressures in the operating temperature range.
Two types of metal hydrides with different equilibrium decomposition pressures were used.
Two sealed containers filled with the metal hydride of the species are communicated so that hydrogen can move to form a working pair, and at least two pairs of the working pairs are provided, and the first metal hydride having a low equilibrium decomposition pressure is used. One sealed container of the first working pair is filled, and the second
A third metal hydride having a higher equilibrium decomposition pressure is filled into the remaining closed containers of the first and second working pairs, and a higher temperature is charged. A metal hydride device characterized in that the metal hydride filling amount of the working pair driven by the driving heat source is greater than the metal hydride filling amount of the working pair driven by the driving heat source of lower temperature. . 2 Different equilibrium decomposition pressures in the operating temperature range 3
Two types of metal hydrides with different equilibrium decomposition pressures were used.
Two sealed containers filled with different metal hydrides are communicated so that hydrogen can move to form a working pair, and at least two pairs of these working pairs are provided, and the first metal hydride having a large equilibrium decomposition pressure is One of the closed containers of the first working pair is filled, and the second
A third metal hydride having a lower equilibrium decomposition pressure is filled into the remaining closed containers of the first and second working pairs, and a higher temperature is charged. A metal hydride device characterized in that the metal hydride filling amount of the working pair driven by the driving heat source is greater than the metal hydride filling amount of the working pair driven by the driving heat source of lower temperature. . 3 Different equilibrium decomposition pressures in the operating temperature range 4
Two types of metal hydrides with different equilibrium decomposition pressures were used.
Two sealed containers filled with the metal hydride of the species are communicated so that hydrogen can move to form a working pair, and at least two pairs of the working pairs are provided, and the first metal hydride having the lowest equilibrium decomposition pressure is provided. is charged into one sealed container of the first working pair, a second metal hydride having the next lowest equilibrium decomposition pressure is filled into one sealed container of the second working pair, and the second metal hydride having the highest equilibrium decomposition pressure is filled with Filling the remaining closed container of the first or second working pair with the metal hydride No. 3, and filling the remaining closed container of the second or first working pair with the metal hydride having the next highest equilibrium decomposition pressure, Metallic hydrogen, characterized in that the amount of metal hydride filling in the working pair driven by a higher temperature driving heat source is greater than the amount of metal hydride filling in the working pair driven by a lower temperature driving heat source. Monster device.