JPS634111B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal energy acquisition method and apparatus.

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 methods and devices for obtaining cold or hot heat using the characteristics of metal hydrides have been proposed, but the efficiency is generally low, so improvements are required.

Figure 1a is a cycle diagram of a conventional thermal energy acquisition method using two metal hydrides M ₁ H and M ₂ H with different equilibrium decomposition pressure characteristics, where the horizontal axis is the reciprocal of the absolute temperature T and the vertical axis is represents the logarithm of the equilibrium decomposition pressure P. Using this cycle diagram, we will calculate the Carnot coefficient of performance COP when obtaining hot or cold heat. Initially, M ₁ H had sufficient hydrogen storage;
Assuming that M ₂ H has released all hydrogen, 1 mole of hydrogen is occluded or released during the cycle, and the reaction heats at this time are ΔH ₁ and ΔH ₂ , respectively.
Heat of ΔH 1 is applied to M ₁ H from a high temperature heating medium at temperature _{T H} to release hydrogen (point A), and this hydrogen is
When M ₂ H is occluded at T _M (< _TH ), M ₂ H generates heat of ΔH ₂ (point B).

Next, when M ₁ H is cooled to a temperature T _M using a medium-temperature heating medium and M ₂ H is cooled to a temperature T _L (<T _M ) using a low-temperature heating medium, M ₂ H is reduced due to the decomposition equilibrium pressure difference. is ΔH ₂
It absorbs heat and releases hydrogen (point C), and this hydrogen is absorbed by M ₁ H, generating heat of ΔH ₁ (point D).
Therefore, one cycle is completed by heating M ₁ H to temperature T _H again and heating M ₂ H to temperature T _M.

In the above cycle, the high temperature heating medium is used as the high temperature driving heat source, cooling water is used as the medium temperature heating medium, the low temperature heating medium is connected to the cooling load, and heat of ΔH ₁ is input to point A, and at points B and C. Cold heat ΔH 2 can be obtained at point D by discharging the heat _generated ΔH ₂ and ΔH ₁ from the system. As is clear from the above explanation, the Carnot coefficient of performance in this cooling/heating cycle is calculated as follows, considering that the slope of the straight line representing the equilibrium decomposition pressure characteristics is equal to the heat of reaction, that is, ΔH ₁ ΔH _2.As is clear from the above explanation, COP _c = ΔH ₂ /ΔH ₁ 1 ...(1).

On the other hand, if the high-temperature heating medium is used as a high-temperature driving heat source and cooling water is used as the low-temperature heating medium, heat can be obtained at points B and D from the medium-temperature heating medium.
In order to distinguish such a heat acquisition cycle from another heat acquisition cycle described later, it will be referred to as a first type heat acquisition cycle here. The Carnot coefficient of performance in this first-class heat acquisition cycle is to input heat of ΔH ₁ to point A, and from points B and D to ΔH ₁ +ΔH ₂
Since the thermal energy of is obtained as output, COP _H1 = ΔH ₁ + ΔH ₂ /ΔH ₁ = 1 + COP _c = 2...(2).

Note that in an actual cycle, heat loss due to heating and cooling between points A and D and between points B and C is unavoidable, so the actual coefficient of performance is considerably smaller than the above value.

Next, FIG. 1b shows a second type heat acquisition cycle. In this cycle, initially, M ₂ H has absorbed enough hydrogen, and M ₁ H has completely released hydrogen, and the temperature is increased by a medium-temperature driving heat source.
At T _M, heat of ΔH ₂ is applied to M ₂ H to release hydrogen (point A), and this hydrogen is heated to a temperature using the equilibrium decomposition pressure difference.
It is occluded by M ₁ H at T _H (>T _M ) (point B). At this time, since M ₁ H generates heat of ΔH ₁ , this is obtained as thermal output. Next, by using a low-temperature heating medium,
M ₂ H is cooled to a temperature T _L (<T _M ), while M ₁ H is cooled to a temperature T _M , and due to the equilibrium decomposition pressure difference between the two,
Hydrogen is released from M ₁ H (point C) and absorbed into M ₂ H (point D). At this time, heat of ΔH ₁ is applied to M ₁ H from the driving heat source, and heat ΔH ₂ generated by M ₂ H is discharged to the low-temperature heat medium. Therefore, the coefficient of performance COP _H2 of this second type thermal cycle is COP _H2 = ΔH ₁ /ΔH ₁ +ΔH ₂ =0.5 (3).

ΔH ₂ ≦ΔH ₁ for most metal hydrides
Therefore, in principle, it is almost impossible for COP _c to exceed 1, and therefore, it is almost impossible for COP _H1 to exceed 2. No, cold or heat
Considering the heat loss due to heating and cooling between points A and D and between points B and C in the seed temperature heat acquisition cycle, the coefficient of performance generally tends to decrease when T _H exceeds a certain limit. The second type thermal cycle uses a medium-temperature driving heat source to obtain high-temperature thermal energy, but its coefficient of performance is originally very small.

As described above, all conventional methods have low coefficients of performance. The present invention was made to solve such problems, and an object of the present invention is to provide a thermal energy acquisition method with an improved coefficient of performance and an apparatus therefor.

The present invention uses a first metal hydride (M ₁ H) with a low equilibrium decomposition pressure and a second metal hydride (M ₂ H) with a high equilibrium decomposition pressure in the operating temperature range. Release hydrogen endothermically from
A cycle in which this hydrogen is exothermically occluded in a second metal hydride, then hydrogen is endothermically released from the second metal hydride, and this hydrogen is exothermically occluded in the first metal hydride. In the thermal energy acquisition method, in which the heat generated due to hydrogen storage of the metal hydride is acquired as thermal heat, or the storage due to hydrogen release of the metal hydride is acquired as cold heat, the hydrogen storage of the second metal hydride is The heat thus generated is applied to a first metal hydride that occludes hydrogen to release hydrogen from the first metal hydride, and the hydrogen is occluded in a second metal hydride. That is.

The present invention will be described below based on drawings showing examples. In the method of the present invention, M ₁ H and M ₂ H
The sets are provided in multiple stages. FIG. 2a shows a cold or hot heat acquisition cycle with two stages and two coarses of M ₁ H and M ₂ H, and the hydrogen transfer within one set of M ₁ H and M ₂ H is represented by a solid line, The simple movement of hydrogen between pairs is shown by a broken line.

In the first set, M ₁ H is the temperature in the high temperature heating medium.
Heating to T ₁ and applying heat of ΔH ₁ to release hydrogen (point A), and absorbing this hydrogen into M ₂ H at temperature T _2h (point B) are the same as in the conventional cycle described above. , in the present invention, the second set of
The temperature is chosen so that M ₁ H is kept at temperature T ₂ l (< T ₂ h) and the equilibrium decomposition pressure is lower than that of M ₁ H.
Keeping M ₂ H at T ₃ l, in this way the first set of
The heat of ΔH ₂ generated by M ₂ H (hereinafter referred to as (M ₂ H) _1. The same applies to other metal hydrides) is given to (M ₁ H) ₂ at a temperature of T ₂ l, and ΔH ₂ /ΔH _One mole of hydrogen is released (point C) and this hydrogen is stored in (M ₂ H) ₂ at a temperature T ₃ l (point D). At this time,
(M ₂ H) ₂ generates heat of (ΔH ₂ /ΔH ₁ )ΔH ₂ , which is discharged to an intermediate temperature heating medium at a temperature of T ₃ l.

Next, both (M ₂ H) ₁ at a temperature of T ₂ h and (M ₂ H) ₂ at a temperature of T ₃ l are cooled to a temperature of T ₄ using a low-temperature heating medium, and (M ₁ H) ₁ at a temperature of T ₁ is and temperature T ₂ l (M ₁ H) ₂ together with temperature
After cooling to T ₃ h, hydrogen is transferred from (M ₂ H) ₁ and (M ₂ H) ₂ to M ₁ H in the same set (point E).
Therefore, the temperature T ₃ h is chosen such that M ₁ H at this temperature has a lower equilibrium decomposition pressure than M ₂ H at temperature T ₄ . At this time, (M ₂ H) ₁ is the temperature
It takes away the heat of ΔH ₂ from the low temperature heat source of T ₄ , and (M ₂ H) ₂ takes away the heat of ΔH ₂ ² /ΔH ₁ . (M ₁ H) ₁ generates heat of ΔH ₁ as it absorbs hydrogen, and (M ₁ H) ₂ generates heat of (ΔH ₂ /
ΔH ₁ ) generates heat of ΔH ₁ (=ΔH ₂ ). This heat is discharged to a heating medium at a temperature T ₃ h.

Therefore, the heat input to the cycle is ΔH ₁ at point A, and the cold heat output is ΔH ₂ +ΔH ₂ ² /ΔH ₁ at point E, so the coefficient of performance of the cold heat acquisition cycle is COP _c = ΔH ₂ +ΔH ₂ ² /ΔH ₁ /ΔH ₁ =ΔH ₂ (ΔH ₁ +ΔH ₂ )/ΔH ₁ ² , and as ΔH ₁ ΔH ₂ , COP _c 2 ...(4).

In addition, the coefficient of performance of the first type thermal cycle that obtains thermal output with miscellaneous D and F is that the heat input to the cycle is ΔH ₁ at point A, so COP _H1 = ΔH ₁ +ΔH ₂ +ΔH ₂ ² /ΔH ₁ /ΔH ₁ =ΔH ₁ ² +ΔH ₁ ΔH ₂ +ΔH ₂ ² /ΔH ₂ 2Here, since ΔH ₁ ΔH ² , COP _H1 3 ( ₅ ) is obtained.

As is clear from comparing these coefficients of performance with Equations (1) and (2) above, the present invention significantly improves the coefficient of performance.

The same is true when three or more pairs of M ₁ H and M ₂ H are provided, and the heat generated by (M ₂ H) ₂ at point D is further applied to (M ₁ H) ₃ to generate hydrogen, and this Hydrogen is absorbed into (M ₂ H) ₃ , and theoretically, as the number of pairs of M ₁ H and M ₂ H increases, the Carnot coefficient of performance also improves.

In the above example, for simplicity, M ₁ H and
I explained an example using two sets of M ₂ H, but M ₁ H
and M ₂ H, and M ₁ H′ which approximates the operating temperature.
Of course, it is also possible to use a set of M ₂ H′.

FIG. 2b shows a second type heat acquisition cycle according to the present invention. In this cycle, heat of ΔH ₁ is applied to (M ₁ H) ₁ at temperature T ₂ to generate hydrogen (point A), and this hydrogen is occluded in (M ₂ H) ₁ at temperature T ₃ h ( Point B). At this time, the heat generated by (M ₂ H) ₁ ΔH ₂
is given to (M ₁ H) ₂ at temperature T ₃ l (< T ₃ h), and ΔH ₂ /
ΔH ₁ mole of hydrogen is generated (point C) and this hydrogen is occluded in (M ₂ H) ₂ at temperature T ₄ (point D). At this time, (M ₂ H) ₂ generates heat of ΔH ₂ ² /ΔH ₁ ,
This heat is discharged to a low temperature heat transfer medium.

Then, (M ₂ H) ₁ and (M ₂ H) ₂ are heated to a temperature T ₂ ,
Heat of ΔH ₂ and ΔH ₂ ² /ΔH ₁ is applied to each to release hydrogen, and (M ₁ H) ₁ and (M ₁ H) ₂ are caused to absorb this hydrogen at a temperature T ₁ . At this time, (M ₁ H) ₁ generates heat of ΔH ₁ , and (M ₁ H) ₂ generates heat of ΔH ₂ . This heat is obtained as thermal heat.

Comparing such a cycle with the cycle in Figure 2a, it is clear that hydrogen transfers from point A to B and from point C to D in Figure 2b, as well as from point B
The donation of the heat of reaction from to C corresponds to the hydrogen transfer from point A to B and from point C to D in FIG. 2a, and the donation of the heat of reaction from point B to C, respectively,
Furthermore, hydrogen transfer from point E to F in FIG. 2b also corresponds to hydrogen transfer from point E to F in FIG. 2a. That is, the cycles in FIGS. 2a and 2b consist of the cycle elements of points A→B→C→D and the points E→
It can be understood that they have in common that they consist of F cycle elements, and the only difference is that the temperature levels at which these two cycle elements are operated are mutually reversed.

Therefore, the Carnot coefficient of performance indicates that the input to the cycle is ΔH ₁ +ΔH ₂ +ΔH ₂ ² / at points A and E.
ΔH ₁ , the output from the cycle is ΔH ₁ at point F
+ΔH ₂ , so COP _H2 = ΔH ₁ (ΔH ₁ +ΔH ₂ )/ΔH ₁ ² +ΔH ₁ ΔH ₂ +ΔH ₂
^2Here , assuming ΔH ₁ ΔH ₂ , COP _H2 = 2/3 (6). The coefficient of performance is improved compared to the above formula (5).

In addition, in FIG. 2b, the temperatures T ₂ at points E and A do not necessarily have to be the same. Also, the second
It will be clear that in figures a and b, the temperatures T ₂ l and T ₃ l need only be lower than the temperatures T ₂ h and T ₃ h, respectively, to the extent that temperature transfer from point B to point C takes place.

In addition, as in the example explained so far, the heat generated by the hydrogen storage of the second metal hydride of the first group is given to the first metal hydride of the second group, and the first metal hydride of the second group is heated. Hydrogen may be released from the second metal hydride of the first set simultaneously.
It is also possible to temporarily store the heat generated in the first metal hydride in another lid heat tank, take it out one after another in a discontinuous manner, and give it to the first metal hydride in the second set.
Furthermore, rather than exchanging the heat of formation between multiple sets of metal hydrides, the heat generated from M 2 H in the set of M ₁ H and M ₂ H is transferred to a heat storage tank at point B in _Figure 2a. The stored heat is given to M ₁ H, which has completed the E→F reaction, and the same M ₁ H and M ₂ H undergo C→D.
It is also possible to carry out the following reaction.

Next, an apparatus for carrying out the method of the present invention will be described.

The device according to the present invention uses a first metal hydride with a low equilibrium decomposition pressure and a second metal hydride with a high equilibrium decomposition pressure in the operating temperature range, and causes the first metal hydride to endothermically release hydrogen. , this hydrogen is exothermically occluded in a second metal hydride, and then,
having a cycle in which hydrogen is endothermically released from the second metal hydride and exothermically absorbed in the first metal hydride, and the heat generated by the hydrogen absorption of the metal hydride is obtained as thermal heat; Alternatively, in a thermal energy acquisition device that acquires heat absorption accompanying hydrogen release from a metal hydride as cold heat, each set is connected to a first reaction vessel containing a first metal hydride so that hydrogen can communicate with the first reaction vessel. a first set and a second set consisting of a second reaction vessel containing a second metal hydride; a second reaction vessel of the first set and a first reaction vessel of the second set; a heat exchanger for exchanging heat between the first metal hydride and the second metal hydride; The heat thus generated is applied to the first metal hydride of the second set to release hydrogen from the first metal hydride and absorb this hydrogen into the second metal hydride of the second set. This feature is characterized in that it allows the user to

Furthermore, the apparatus of the present invention uses a first metal hydride with a low equilibrium decomposition pressure and a second metal hydride with a high equilibrium decomposition pressure in the operating temperature range, and
causing hydrogen to be released endothermically from a second metal hydride, and exothermically occluding this hydrogen in a second metal hydride;
Next, it has a cycle in which hydrogen is endothermically released from the second metal hydride and this hydrogen is exothermically absorbed into the first metal hydride, and the heat generated by hydrogen absorption in the metal hydride is converted into heat. In a thermal energy acquisition device that acquires hydrogen from a metal hydride or acquires heat absorption accompanying hydrogen release from a metal hydride as cold energy, each set is
a first reaction vessel containing a metal hydride and a second reaction vessel containing a second metal hydride connected to the first reaction vessel so that hydrogen can communicate therewith; and a second reaction vessel containing a second metal hydride. and a heat exchanger for exchanging heat between the second reaction vessel of the first set and the first reaction vessel of the second set, and in the first set, hydrogen is added to the first metal hydride. is released, the hydrogen is exothermically stored in a second metal hydride, and the heat generated by the hydrogen storage is imparted to the first metal hydride of the second set to absorb the hydrogen into the first metal hydride. releasing hydrogen from a hydride and occluding the hydrogen in a second metal hydride of a second set, and having third and fourth sets symmetrically to the first and second sets, and , a heat exchanger for mutually exchanging heat between the first reaction vessels and a heat exchanger for mutually exchanging heat between the second reaction vessels in the corresponding first and third sets and the second and fourth sets. and in each corresponding set, when one set finishes releasing and storing hydrogen in a high temperature range and the other set finishes releasing and storing hydrogen in a low temperature range, the corresponding reaction vessel The feature is that heat is exchanged between the two.

FIG. 3 shows an embodiment of the apparatus of the present invention.

This device is a batch type thermal energy acquisition device that performs a two-stage cycle. 1, 3, 5, 7 are
Reaction vessels containing M ₁ H, 2, 4, 6, 8 are
It is a reaction vessel containing M ₂ H, in which 1 and 2 form a first set, and 3 and 4 form a second set. Similarly, 5 and 6 form the third set, 7 and 8 form the fourth set, and 5
The reaction vessels 1 to 8 are arranged symmetrically with respect to the reaction vessels 1 to 4, and perform the same operation half a cycle later than the cycle performed by the reaction vessels 1 to 4.

A high temperature heat medium 23 at a temperature T ₁ is connected to the reaction vessel 1 by a pump 9 for heat exchange, and
A medium-temperature heat medium (for example, cooling water) 24 at a temperature of T ₃ is connected to the reaction vessels 1, 3, and 4 for heat exchange by pumps 10, 11, and a low-temperature heat medium 25 at a temperature of T ₄ is connected to the reaction vessels 1, 3, and 4 for heat exchange. Pump 13,1 to 2 and 4
4 for heat exchange. Also,
A heat exchanger 31 is provided so that heat can be exchanged between reaction vessels 2 and 3. The heat exchanger 31 is, for example, a heat medium circulation pipe equipped with a pump 17. M ₁ H
To allow hydrogen transfer between and M ₂ H,
Hydrogen communication pipes 41 and 42 provided with control valves 26 and 27 between reaction vessels 1 and 2 and between reaction vessels 3 and 4, respectively.
is installed.

As mentioned above, the reaction vessels 5 to 8 were symmetrical to the reaction vessels 1 to 4, respectively, and were similarly connected to high temperature, medium temperature, and low temperature heating medium, and a pump 18 was provided between reaction vessels 6 and 7. A heat exchanger 32 is provided between reaction vessels 5 and 6 and between reaction vessel 7.
and 8, hydrogen communication pipes 43 and 44 are provided with control valves 28 and 29, respectively.

Furthermore, in the apparatus of the present invention shown in FIG. 3, in order to reduce heat loss due to heating and cooling of the reaction vessels themselves, a reaction vessel 5 is arranged symmetrically with reaction vessels 1 to 4.
Heat medium circulation pipes each having pumps 19 to 22 are disposed between the heat exchangers 33 to 8 and the heat exchangers 33 to 36, respectively. Heat exchange between the reaction vessel and the heat medium, heat exchange between the reaction vessels, and opening/closing of the hydrogen communication pipe are performed by temporally controlling pumps, control valves, and switching valves (not shown) provided in the heat medium flow path. complete the cycle.

Figure 4 shows the hydride of LaNi _4.7 Al _0.3 as M ₁ H,
The cold heat and first type heat acquisition cycles are shown when LaNi ₅ hydride is used as M ₂ H, and FIG. 5 shows a timing chart of the operation of the device.

As the starting point of the cycle, the first set of reaction vessels 1 and 2 are at points A and F, respectively;
The hydrogen transfer from (M ₂ H) ₁ to (M ₁ H) ₁ is completed and the second set of reaction vessels 3 and 4 are also at points A and F respectively.
In this case, hydrogen transfer from (M ₂ H) ₂ to (M ₁ H) ₂ is completed, and reaction vessels 5, which correspond to reaction vessels 1 to 4 and operate with a half-cycle delay,
For 8 to 8, the third set of reaction vessels 5 and 6
are at points C and D, respectively, the hydrogen transfer from (M ₁ H) ₁ to (M ₂ H) ₁ is completed, and the fourth set of reaction vessels 7 and 8 are at points B and E, respectively. , the reaction vessel 7 releases hydrogen by supplying heat from the reaction vessel 6, and the reaction vessel 8 stores this hydrogen. The operating positions of these reaction vessels are shown in FIGS. 4 and 5.

Step 1 in the cycle is heat exchange between corresponding reaction vessels arranged symmetrically, with heat exchanger 33 between reaction vessels 1 and 5, 2 and 6, 3 and 7, and 4 and 8, respectively. , 34, 35, and 36 to reduce the amount of hot or cold heat required for the next step of heating or cooling each reaction vessel. The position of each reaction vessel on the cycle diagram after the completion of this heat exchange step is shown at the right end of the step 1 column in FIG.

Step 2 is to remove the reaction vessels 1 and 5 after the heat exchange is completed.
and 7 to a predetermined temperature by heat exchange with a heating medium.
is heated to the position of point C by high-temperature heating medium 23,
On the other hand, both reaction vessels 5 and 7 are cooled to point A by the low-temperature heating medium 25. Other reaction vessels are left alone without being heated or cooled.

Next, as step 3, the control valves 26, 27,
28 and 29, all hydrogen communication pipes are opened, and hydrogen is transferred from reaction vessels 1 to 2, 3 to 4, 6 to 5, and 8 to 7. Hydrogen transfer from reaction vessel 1 to 2 is hydrogen transfer from point C to D in the cycle diagram, and similarly hydrogen transfer from reaction vessel 3 to 4, 6 to 5, and 8 to 7 is at point B, respectively. to E, from point F to A, and from point F to A. In this step, reaction vessels 6 and 8 remove heat from low-temperature heat source 25 as hydrogen is released from M ₂ H, and reaction vessels 4, 5 and 7 transfer heat to medium-temperature heat medium 24 as hydrogen is absorbed. give. Therefore, if the high temperature heat medium 23 is used as a driving heat source, the medium temperature heat medium 24 is used as cooling water, and the low temperature heat medium 25 is connected to a cooling load, a cooling function can be obtained, while the high temperature and low temperature heat medium 25 are used as a driving heat source. year,
A heating function can be obtained by connecting the medium temperature heat medium 24 to a heating load. In this way, the half cycle ends at step 3.

At the end of step 3, reaction vessels 1 to 8 are at points C, D, B, E, A, F, A and F, respectively, and the positions of reaction vessels 1 to 4 are the same as those of reaction vessels 5 to 8 at the start of the step. Corresponds to the hour position. Therefore, in the latter half cycle consisting of steps 4 to 6, the operation of reaction vessels 1 to 4 and the operation of reaction vessels 5 to 8 are only alternated, and the explanation thereof will be omitted.

The coefficient of performance of the device is determined based on the above operations. In order to simplify the calculation, the amount of hydrogen transferred between reaction vessels 1 and 2 and between reaction vessels 5 and 6 is assumed to be 1 mole, and the amount of hydrogen transferred per 1 mole of reaction hydrogen of M ₁ H and M ₂ H is calculated as follows. Let the heat of reaction be ΔH ₁ and ΔH ₂ , respectively, and let J be the heat capacity per mole of reaction hydrogen of the metal hydride and the reaction vessel. Furthermore, in heat exchange between reaction vessels, the temperature of the high temperature reaction vessel is
Th, the temperature of the low-temperature reaction vessel is Tc, the temperature corresponding to the midpoint of Th and Tc is Tm, that is, (Th + Tc) / 2
Tm, the temperature of the high temperature reaction vessel after heat exchange is Th′,
Letting the temperature of the low-temperature reaction vessel be Tc', the heat exchange efficiency η is determined as follows.

η=Th-Th'/Th-Tm=Tc-Tc'/Tc-Tm Tm means the temperature of each reaction vessel when heat exchange between the reaction vessels is complete. Using the heat exchange efficiency η, the temperature of the high temperature reaction vessel after heat exchange is given by Th′=Th−η(Th−Tc)/2, and the temperature of the low temperature reaction vessel is given by Tc′=Tc+η(Tc− Th)/2.

In FIG. 4, when the reaction vessels at points C and A are subjected to heat exchange, they reach points M and G, respectively, and when the reaction vessels at points D and F are exchanged heat, they are reached at point N, respectively.
and H, and when the reaction vessels at points B and A are subjected to heat exchange, points K and I are reached respectively, and point E is reached.
Suppose that when the reaction vessels of and F are subjected to heat exchange, they reach points L and J, respectively.

Therefore, in the cycle diagram, points C, D, B,
The temperatures of A(E) and F are T ₁ , T ₂ h, T ₂ l, respectively.
T ₃ and T ₄ , the amount of heat required to heat the reaction vessel 1 from point G to C in step 2 is J
(T ₁ − T ₃ )(1−η/2), and then the amount of heat required to transfer hydrogen from (M ₁ H) ₁ to (M ₂ H) ₁ in step 3 is ΔH ₁ . be. At this time, (M ₂ H) ₁ generates heat of ΔH ₂ as it absorbs hydrogen, but of this, J(T ₂ h−T ₄ )( 1-η/2), so the reaction vessel 3 has ΔH ₂ −J
The quantity (T ₂ h−T ₄ )(1−η/2) is given. This amount of heat contributes to hydrogen transfer from point B to E, i.e. from (M ₁ H) ₂ to (M ₂ H) ₂ , excluding the heat consumed to heat the reaction vessel 3 from point I to B. is,
If the amount of hydrogen transferred by this is x mole, then
The heat required to heat the reaction vessel 3 from point I to B is xJ(T ₂ l−T ₃ )(1−η/2), and the amount of heat provided for hydrogen transfer is xΔH ₁ , therefore, at point E The heat generated by (M ₂ H) ₂ is xΔH ₂ .

Note that x can be obtained from the following equation.

x= _ΔH2 −J( _T2h − _T4 )(1−η/2)−xJ(T
₂ l−T ₃ )(1−η/2)/ΔH ₁ On the other hand, as hydrogen moves from point F to A, that is, from (M ₂ H) ₂ to (M ₁ H) ₂ , the reaction vessel 6 From the low-temperature heating medium 25, ΔH ₂ −J(T ₂ h−T ₄ )(1−η/
2), and the reaction vessel 8 also receives x(ΔH ₂ −
Removes heat from J(T ₃ −T ₄ )(1−η/2).

This completes the first half cycle, and in this half cycle, high temperature heat medium 2 is used to drive the device.
3, the amount of heat input to the device is ΔH ₁ +J(T ₁ −T ₃ )(1−η/2) (7), and the amount of heat obtained from the low-temperature heating medium 25 is ΔH ₂ −J(T ₂ h−T ₄ )(1-η/2)+xΔH2 _- J( _T3 - _T4 )(1-η/2)) (8), and the amount of heat released by the device to the medium temperature heating medium 24 is _ΔH1 -J( T ₁ −T ₃ ) (1−η/2)+ΔH ₂ −J(T ₂ h−T ₄ )(1−η/2)+x(ΔH ₂ −J(T ₃ −T ₄ )(1−η/ 2)) (9).

For the latter half cycle, the above equations (7), (8) and
Since (9) can be obtained in the same way, the cold heat gain coefficient of performance is COP _c = (8)/(7) (10) The first type heat gain coefficient of performance is COP _H1 = (9)/(7) = ( (7)+(8))/(7)=1+COP _c (11).

So for LaNi _4.7 Al _0.3 , ΔH ₁ = 8.1
(Kcal/mole H ₂ ), ΔH ₂ = 7.4 for LaNi ₅
(Kcal/mol _H2 ), and as J, we will omit the calculation process, but choose a reasonable value of 0.04Kcal/mol _H2・℃, T ₁ = 140℃, T ₂ h = 85℃, T ₂ l =80℃, _T3
= 40°C, T ₄ = 10°C, and the change in COP _c with respect to η is shown by the solid line in Figure 6a.

To determine the COP _c in the conventional apparatus, consider the cycle of points B, E, F, and A in Figure 4. J(T ₂ l−T ₃ )(1−η/
2) and ΔH ₁ to make (M ₁ H) ₁ release hydrogen.
Input the heat amount of (M ₂ H) ₂ and the reaction heat ΔH ₂ of reaction vessel 2 after heat exchange between the reaction vessels.
Cold heat J (T ₃ − T ₄ ) for cooling from point H to F
(1-η/2) can be obtained, so COP _c =ΔH ₂ −J(T ₃ −T ₄ )(1−η/2)/ΔH ₁ +J
It is given by (T ₂ l−T ₃ )(1−η/2)(12). The change in COP _c with respect to η is shown in 6th a.
It is indicated by the broken line I in the figure. Normally, η≧0.5 is sufficient, so
It is clear that the present invention improves the coefficient of performance.

In addition, as for the conventional cycle, point C in Fig. 4,
Considering the cycle of E, F, A, COP _c is expressed as Equation (12)
is obtained by replacing T ₂ l with T ₁ in , and the variation of COP _c with respect to η is shown by the dashed line in Figure 6a, and COP _c
The improvement will be easily understood.

The second type heat acquisition cycle is shown in FIG. 7, as described above, from point C to D, from B to E, and from F to A.
Since the hydrogen transfer to corresponds to the hydrogen transfer between the same symbols in FIG. 4, and the transfer of reaction heat from point B to D also corresponds, a description of the operation of the cycle will be omitted.

In the second type heat acquisition cycle, ΔH ₁ −J(T ₁ −T ₂ )(1−η/2) (13) is input at point C, and ΔH ₂ +I(T ₂ −T ₃ h)( 1−η/2)+x(ΔH ₂ +J(T ₂ −T ₄ )(1−η/2)) (14) is input.

x=ΔH ₂ −J(T ₂ −T ₃ h)(1−η/2)/ΔH ₁ +J
(T ₁ −T ₃ l)(1−η/2).

On the other hand, the thermal output obtained at point A is H ₁ - J (T ₁ - T ₂ ) (1 - η/2) + x (ΔH ₁ - J (T ₁ - T ₃ l) (1 - η/2) ( 15), so COP _H2 = (15)/((13)+(14)) (16).

Here, T ₁ = 120℃, T ₂ = 80℃, T ₃ h = 40℃,
COP _H2 for η, assuming T ₃ l = 35℃, T ₄ = 0℃
The change in is shown in FIG. 8 by a solid line.

Considering the cycle of points C, D, F, and A as a conventional cycle, COP _H2 = ΔH ₁ − J (T ₁ − T ₂ ) (1−η/2)/ΔH ₁ +ΔH
₂ −J(T ₁ −2T ₂ +T ₃ h)(1−η/2), and the change in COP _H2 with respect to η is shown by the broken line I in Figure 8.
Shown in Also, as a conventional cycle, point C,
Considering the cycle of E, F, A, COP _H2 = ΔH ₁ − J (T ₁ − T ₂ ) (1−η/2)/ΔH ₁ + ΔH
₂ −J(T ₁ −T ₂ )(1−η/2)+J(T ₂ −T ₄ )(1−
η/2). The change in COP _H2 with respect to η is shown by the broken line in Figure 8.

In the apparatus of the present invention shown in FIG. 3 above, reaction vessels 1 and 5, 2 and 6, located symmetrically,
Between 3 and 7 and 4 and 8, heat is exchanged between the corresponding reaction vessels when hydrogen release and storage are completed, reducing heat loss and further improving the coefficient of performance of the device. It will be easily understood that the apparatus of the present invention can be implemented even if this heat exchange that does not involve driving the reaction between reaction vessels is omitted.

That is, by omitting heat exchange that does not involve reaction drive between the reaction vessels of the apparatus shown in FIG. 3, the installation of pumps 19 to 22 and heat exchangers 33 to 36 shown in FIG. 3 is unnecessary. The advantage is that no additional equipment or power source is required for its operation. Furthermore, it is also possible to omit the series of reaction vessels 5, 6, 7, 8, except for the disadvantage that the output of the apparatus becomes discontinuous.

Next, another device of the present invention will be explained. The device of the present invention uses a first metal hydride with a low equilibrium decomposition pressure and a second metal hydride with a high equilibrium decomposition pressure in the operating temperature range, and causes the first metal hydride to endothermically release hydrogen. , this hydrogen is exothermically occluded in a second metal hydride, then hydrogen is endothermically released from the second metal hydride, and this hydrogen is exothermically occluded in the first metal hydride. In a thermal energy acquisition device that has a cycle and acquires the heat generated by hydrogen absorption of a metal hydride as thermal heat, or acquires the heat absorbed due to hydrogen release of a metal hydride as cold heat, each set is a first metal hydride. a second reaction vessel containing a second metal hydride connected to the first reaction vessel so that hydrogen can communicate therewith; and a second reaction vessel containing a second metal hydride in the second reaction vessel. It is characterized by comprising a heat storage tank that receives heat generated by hydrogen storage and provides the heat to the first metal hydride in the first reaction vessel.

FIG. 9 shows an embodiment of the inventive device. 1,
3 is a reaction vessel containing M ₁ H, 2 and 4 are reaction vessels containing M ₂ H, and reaction vessels 1 and 2 and reaction vessels 3 and 4 form a set, respectively. temperature
The high temperature heat medium 23 at T ₁ is connected to the reaction vessels 1 and 3 by a pump 9 so as to be able to exchange heat, and the temperature T ₃
A medium-temperature heat medium 24 is connected to the reaction vessels 1, 2, 3, and 4 by pumps 10, 11 in a heat exchangeable and connectable manner, and a low-temperature heat medium 25 at a temperature of _T4 is
are connected to the reaction vessels 2 and 4 by a pump 13.

A heat storage tank 45 is provided between the reaction vessels 1, 2, 3, and 4. The heat storage tank 45 is the heat exchanger 29, 3
0, 31 and 32 respectively indicate reaction vessel 2,
4, 1, and 3, so that the heat generated by the reaction vessels 2 and 4 can be received, and the heat accumulated in the reaction vessels 1 and 3 can be given to the reaction vessels 1 and 3 as appropriate.
The heat exchangers 29, 30, 31, and 32 are equipped with pumps 15, 16, 17, and 18, respectively.

Hydrogen communication pipes 41 and 42 equipped with control valves 26 and 27 are provided between reaction vessels 1 and 2 and between 3 and 4. Between reaction vessels 1 and 3, and between 2 and 4
In between is a heat exchanger 3 equipped with pumps 19 and 20.
3 and 34 are arranged. Note that switching valves and the like provided in the heat medium flow path are omitted.

In the device of the present invention shown in FIG. 9, as M ₁ H
The cold heat and type 1 heat acquisition operations when using a hydride of LaNi _4.7 Al _0.3 and a hydride of LaNi ₅ as M ₂ H will be explained using FIG. 4. As the starting point of the cycle, reaction vessels 1 and 2 are at points A and F, respectively.
At this time, the hydrogen transfer from M ₂ H to M ₁ H has been completed, and the reaction vessels 3 and 4 are at points C and D, respectively, and the hydrogen transfer from M ₁ H to M ₂ H has been completed. Think about the situation you are in.

Next, the control valves 26 and 27 are closed, and the heat exchanger 3
3 and 34 between reaction vessels 1 and 3 and 2 and 4, reaction vessels 1, 2, 3, and 4 reach points K, L, M, and N, respectively. Next, the reaction vessel 1 is heated to point C using the high temperature heating medium 23, and the reaction vessel 3 is cooled to point A using the medium temperature heating medium 24. and,
Control valves 26 and 27 are opened, and reaction vessels 1 and 2 transfer hydrogen from M ₁ H to M ₂ H between points C and D, and reaction vessels 3 and 4 transfer hydrogen from M ₂ H to M between points A and F. Performs _1H hydrogen transfer. At point F, heat is taken from the low-temperature heating medium 25 as hydrogen is released from (M ₂ H) ₄ , and at point D, heat is generated as hydrogen is absorbed by (M ₂ H) ₂ .
T ₂ is stored in the heat storage tank 45 by the heat exchanger 29 . Therefore, if the high temperature heat medium 23 is used as the driving heat source, the medium temperature heat medium 24 is used as outside air, and the low temperature heat medium 25 is connected to the cooling load, a cooling function can be obtained. A heating function can be obtained by connecting the medium-temperature heat medium 24 to a heating load as a heat source. Reaction vessels 1, 2, 3, and 4 are for heat exchange and heating;
Proceed to the next step (initial state) by moving through cooling as follows.

Reaction vessel 1; C→M→A Reaction vessel 2; D→N→F Reaction vessel 3; A→K→C Reaction vessel 4; F→L→D Hydrogen storage at point C (M ₂ H) ₂ or ( The heat generated from M ₂ H) ₄ is stored in a heat storage tank 45, and is transferred to the heat exchanger 31 or 3 as appropriate (for example, once per cycle).
2 and give it to (M ₁ H) ₁ or (M ₁ H) ₃ which has sufficiently absorbed hydrogen. (M ₁ H) ₁ or (M ₁ H) ₃ releases hydrogen at point B, and it is stored in (M ₂ H) ₂ or (M ₂ H) ₄ , which is cooled by the intermediate temperature heating medium 24. At this time, (M ₂ H) ₂ or (M ₂ H) ₄ is located at point E.

To reach point B, reaction vessel 1 or 3 moves from A→K→
B, and A→K is transferred by heat exchange with reaction vessel 3 or 1, and the heat provided except for the heat for heating K→B is used for hydrogen release. Point E
The reaction vessel 2 or 4 located at point F moves from E→H→F, and E→H moves by heat exchange with reaction vessel 4 or 2, and in order to release hydrogen at point F, H→F
It is only necessary to cool the reaction vessel 2 or 4 by the amount of time required. Similarly, reaction vessel 3 or 1 at point A moves from A to I to C,
The reaction vessel 4 or 2 at point F moves from F to J to D to proceed to the next step (cycle of A to C to D to F).
to move to.

In this way, the apparatus shown in FIG. 9 can also effectively utilize the driving heat source from the high temperature heat medium 23 in multiple stages. Note that the principle of operation in the second type heat acquisition cycle is the same, so the explanation will be omitted.

In the above example, the metal hydride is charged into an independent reaction vessel and the reaction is carried out in a _batch manner.
It may also be one that encapsulates M ₂ H or one that continuously transfers metal hydrides to different heat sources.

As described above, according to the present invention, when hydrogen is transferred from M ₁ H to M ₂ H in the first set, M ₂ H
The heat generated by the _second
to M ₁ H of the set, thereby transferring hydrogen from M ₁ H to M ₂ H in the second set, and if desired, in turn from the second set to the third set,
Since heat is donated and hydrogen is transferred from M ₁ H to M ₂ H, the driving thermal energy required for hydrogen transfer is saved. In other words, a large amount of hydrogen is transferred with a small amount of driving thermal energy, and from M ₂ H to M ₁ H
The coefficient of performance of the device is significantly improved because cold or hot heat is obtained when hydrogen is transferred to the device.

[Brief explanation of the drawing]

Figure 1a is a conventional cold or type 1 heat acquisition cycle diagram using two types of metal hydrides with different equilibrium decomposition pressure characteristics, Figure 1b is a type 2 heat acquisition cycle diagram, and Figure 2a is a diagram of this type of heat acquisition cycle. Figure 2b is a diagram of a cold or first type heat acquisition cycle according to the method of the invention; Figure 3 is a diagram of a second type heat acquisition cycle; Figure 4 is a cold heat or type 1 heat acquisition cycle diagram using the apparatus shown in Figure 3, Figure 5 is a timing chart showing the operation of the apparatus shown in Figure 3, and Figure 6 is a conventional graph showing the heat exchange efficiency η between reaction vessels. and a graph showing the coefficient of performance of cooling or heating obtained by the cycle of FIG. 4,
Fig. 7 is a second type heat acquisition cycle diagram for the apparatus shown in Fig. 3, Fig. 8 is a graph showing the second type heat acquisition coefficient of performance for conventional and Fig. 7 cycles against η, and Fig. 9 is a graph of the present invention. FIG. 3 is a layout diagram showing different examples of an apparatus for carrying out the method of FIG. 1, 5... A first set of reaction vessels containing M ₁ H, 3, 7... A second set of reaction vessels containing M ₁ H, 2, 6... The first set of reaction vessels containing M ₂ H. 1 set of reaction vessels, 4, 8... Second set of reaction vessels containing M ₂ H, 23... High temperature heat medium, 24... Medium temperature heat medium, 25... Low temperature heat medium, 31, 32 ,33,3
4, 35, 36... Heat exchanger, 41, 42, 4
3, 44...Hydrogen communication pipe, 45...Heat storage tank.

Claims (1)

[Claims] 1. A first compound having a low equilibrium decomposition pressure in the operating temperature range.
Using a second metal hydride having a high equilibrium decomposition pressure with the metal hydride, hydrogen is endothermically released from the first metal hydride, and this hydrogen is exothermically occluded in the second metal hydride, Next, it has a cycle in which hydrogen is endothermically released from the second metal hydride and this hydrogen is exothermically absorbed into the first metal hydride, and the heat generated by hydrogen absorption in the metal hydride is converted into heat. In the method for acquiring thermal energy in which the heat generated by the hydrogen absorption of the metal hydride is acquired as cold heat, the heat generated by the hydrogen absorption of the second metal hydride is transferred to the first metal occluding hydrogen. 1. A method for obtaining thermal energy, which comprises supplying hydrogen to a hydride to release hydrogen from the first metal hydride, and occluding the hydrogen in a second metal hydride. 2 At least two sets of first and second metal hydrides are provided, and the heat generated by hydrogen absorption of the second metal hydride of the first set is transferred to the first metal hydride of the second set. The heat according to claim 1, characterized in that the heat is applied to a first metal hydride to release hydrogen from the first metal hydride, and to occlude this hydrogen in a second metal hydride of a second set. Energy acquisition method. 3. The first one has a lower equilibrium decomposition pressure in the operating temperature range.
Using a second metal hydride having a high equilibrium decomposition pressure with the metal hydride, hydrogen is endothermically released from the first metal hydride, and this hydrogen is exothermically occluded in the second metal hydride, Next, it has a cycle in which hydrogen is endothermically released from the second metal hydride and this hydrogen is exothermically absorbed into the first metal hydride, and the heat generated by hydrogen absorption in the metal hydride is converted into heat. In a thermal energy acquisition device that acquires hydrogen from a metal hydride or acquires the endothermic energy associated with hydrogen release from a metal hydride as cold heat, each set includes a first reaction vessel containing a first metal hydride so that hydrogen can communicate with the first reaction vessel. a first set and a second set consisting of a second reaction vessel containing a second metal hydride connected to the second set; a heat exchanger for exchanging heat with a reaction vessel, in the first set, the first metal hydride releases hydrogen, the second metal hydride absorbs this hydrogen exothermically, and the second metal hydride absorbs hydrogen. The heat generated by hydrogen storage is applied to the first metal hydride of the second set to release hydrogen from the first metal hydride and transfer the hydrogen to the second set of metal hydrides.
A thermal energy acquisition device characterized in that the second metal hydride of the set is occluded. 4. The first one with the lowest equilibrium decomposition pressure in the operating temperature range.
Using a second metal hydride having a high equilibrium decomposition pressure with the metal hydride, hydrogen is endothermically released from the first metal hydride, and this hydrogen is exothermically occluded in the second metal hydride, Next, it has a cycle in which hydrogen is endothermically released from the second metal hydride and this hydrogen is exothermically absorbed into the first metal hydride, and the heat generated by hydrogen absorption in the metal hydride is converted into heat. In a thermal energy acquisition device that acquires hydrogen from a metal hydride or acquires the endothermic energy associated with hydrogen release from a metal hydride as cold heat, each set includes a first reaction vessel containing a first metal hydride so that hydrogen can communicate with the first reaction vessel. a first set and a second set consisting of a second reaction vessel containing a second metal hydride connected to the second set; a heat exchanger for exchanging heat with a reaction vessel, in the first set, the first metal hydride releases hydrogen, the second metal hydride absorbs this hydrogen exothermically, and the second metal hydride absorbs hydrogen. The heat generated by hydrogen storage is applied to the first metal hydride of the second set to release hydrogen from the first metal hydride and transfer the hydrogen to the second set of metal hydrides.
and occluding it in the second metal hydride of the group,
having a third and fourth set symmetrically of the first and second sets, and mutually connecting the first reaction vessels in the corresponding first and third sets and the second and fourth sets; It has a heat exchanger that exchanges heat with the second reaction vessel and a heat exchanger that exchanges heat with the second reaction vessel, and in each corresponding set, one set finishes releasing and occluding hydrogen in a high temperature range. A thermal energy acquisition device characterized in that when the other set finishes releasing and occluding hydrogen in a low temperature range, heat is exchanged between corresponding reaction vessels. 5. The first one with the lowest equilibrium decomposition pressure in the operating temperature range.
Using a second metal hydride having a high equilibrium decomposition pressure with the metal hydride, hydrogen is endothermically released from the first metal hydride, and this hydrogen is exothermically occluded in the second metal hydride, Next, it has a cycle in which hydrogen is endothermically released from the second metal hydride and this hydrogen is exothermically absorbed into the first metal hydride, and the heat generated by hydrogen absorption in the metal hydride is converted into heat. In a thermal energy acquisition device that acquires hydrogen from a metal hydride or acquires the endothermic heat associated with hydrogen release from a metal hydride as cold heat, each set includes a first reaction vessel containing a first metal hydride so that hydrogen can communicate with the first reaction vessel. a second reaction vessel containing a second metal hydride connected to the second reaction vessel; and a heat storage tank for supplying the first metal hydride in the reaction vessel.