JP2014185833A - Heat storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat storage device including a heat medium circulation system with less heat exchange loss.SOLUTION: A heat exchange device includes: a heat utilization device that performs a heat generating operation and a heat absorbing operation; a heat storage tank including a heat storage material that stores therein waste heat generated when the heat utilization device performs the heat generating operation and that supplies the heat stored in the heat storage material during the heat absorbing operation; a heat medium circulation path passing through the heat utilization device and the heat storage tank and circulating a heat medium that performs heat exchange with each of the heat utilization device and the heat storage tank; a heat exchanger provided in the heat medium circulation path; and a circulation device circulating the heat medium in the heat medium circulation path. The heat medium circulation path includes a plurality of heat exchange channels passing through the heat utilization device and the heat storage tank, and the heat exchange channels are connected in series in a consecutive manner.

Description

  Embodiments of the present invention relate to a heat storage device used in a hydrogen power storage device or the like.

  Development of the use of renewable energy is being promoted as a countermeasure against global warming, and some have been put into practical use. As one of them, renewable energy such as wind power and solar power generation is rapidly spreading as a safe energy source without fear of depletion. One of the important problems in this renewable energy is the problem that the output fluctuates greatly due to climate factors. As a method for leveling the output, hydrogen power storage technology is being studied along with a method using pumped-storage power generation and a method using a storage battery.

  In particular, in hydrogen power storage using a solid oxide fuel cell / high-temperature steam electrolysis cell (SOFC / SOEC cell), conversion efficiency is expected to be high. As hydrogen power storage using SOFC / SOEC cells, the applicant of the present application has already been proposed as a power storage system and its operation method.

  The conventional power storage system has a configuration schematically shown in FIGS. FIG. 7 shows a configuration when the SOFC / SOEC cell 1 is used as the SOFC cell 1a (solid oxide fuel cell). FIG. 8 shows a configuration when the SOFC / SOEC cell 1 is used as the SOEC cell 1b (high temperature steam electrolysis cell).

  First, the SOFC cell 1a will be described with reference to FIG. Hydrogen gas stored in the hydrogen tank 9 flows through the flow paths 20a to 20f. That is, the hydrogen gas in the hydrogen tank 9 is supplied to the heat exchanger 4a through the flow paths 20a and 20b. The hydrogen gas heated by the heat exchanger 4a is supplied to the anode electrode 16a of the SOFC cell 1a through the flow path 20c.

Air is supplied to the cathode electrode 16b of the SOFC cell 1a, and oxygen atoms that have received electrons at the cathode electrode 16b become oxygen ions (O ₂₋ ions). The oxygen ions are carried to the electrolyte 17 disposed between the anode electrode 16a and the cathode electrode 16b, and reach the anode electrode 16a while undergoing an exchange reaction with the electrolyte material. Here, in combination with hydrogen gas, electrons are emitted and water is created. The emitted electrons are taken out as electric power.
The anode electrode 16a and the cathode electrode 16b are configured as, for example, porous electrodes, and the electrolyte 17 is configured as, for example, a solid oxide electrolyte.

  The produced hydrogen gas that is not bonded to water and oxygen ions is supplied to the heat exchanger 4a through the flow path 20d, and the heat of the water and hydrogen gas passes through the heat exchanger 4a. This is used to warm the hydrogen gas supplied to the SOFC cell 1a.

  The water and hydrogen gas exiting the heat exchanger 4a obtain a driving force from the blower 5a provided in the flow path 20e, and are supplied to the hydrogen separator 11 through the flow path 20f. The hydrogen gas separated by the hydrogen separator 11 is stored in the hydrogen tank 9 through the flow paths 21b and 20a or used for resupply to the SOFC cell 1a. The water separated by the hydrogen separator 11 is discharged to the outside through the flow path 21a.

  The air supplied to the cathode electrode 16b of the SOFC cell 1a obtains a propulsive force from the blower 5b provided in the flow path 25a and is supplied to the heat exchanger 4b. After being heated by the heat exchanger 4b, it is supplied to the SOFC cell 1a through the flow path 25b. Oxygen, nitrogen, and the like that have not become oxygen ions at the cathode electrode 16b of the SOFC cell 1a are supplied to the heat exchanger 4b through the flow path 25c, and the oxygen, nitrogen, etc. supplied to the heat exchanger 4b have The heat that is used is used to heat the air supplied to the cathode electrode 16b of the SOFC cell 1a by the heat exchanger 4b. Oxygen and nitrogen exiting the heat exchanger 4b will be released into the atmosphere.

Between the SOFC cell 1a and the heat storage tank 2, there is a circulation path 3 for circulating nitrogen gas (N ₂ gas), which is a heat medium, and the heat generated in the SOFC cell 1a during power generation is waste heat. However, it can be taken out from the SOFC cell 1a by warming the nitrogen gas with the waste heat at this time. The extracted heat can be stored in the heat storage tank 2. That is, the nitrogen gas can flow out in the heat exchange flow path 3a passing through the SOFC cell 1a and the heat storage tank 2, thereby taking out waste heat from the SOFC cell 1a and storing it in the heat storage tank 2.
In addition, a blower 5 that gives propulsive force to the nitrogen gas is disposed in the circulation path 3.

  Since the heat storage temperature in the heat storage tank 2 is as high as 800 ° C., for example, it is better to use the blower 5 operating at a temperature of about 300 ° C. instead of using the blower 5 operating at a high temperature of 800 ° C. Is realistic. Therefore, the nitrogen gas emitted from the heat storage tank 2 is configured by arranging the heat exchanger 4 between the heat storage tank 2 and the upstream side of the blower 5 and between the SOFC cell 1a and the downstream side of the blower 5. This temperature can be taken out by the heat exchanger 4 and lowered to nearly 300 ° C., and the heat taken out by the heat exchanger 4 can be used to heat the nitrogen gas supplied to the SOFC cell 1a.

  Next, the SOEC cell 1b will be described with reference to FIG. In FIG. 8, the SOFC / SOEC cell 1 shown in FIG. 7 is used as the SOEC cell 1b. The positions of the anode electrode 18b and the cathode electrode 18a in the SOEC cell 1b and the heat exchanger 4 and the blower 5 are arranged. The other configuration is the same as that of FIG. 7 except that the piping configuration is different.

  That is, in the SOEC cell 1b, electric power is supplied from the outside in order to electrolyze water vapor, and the heat stored in the heat storage tank 2 is used for the heat necessary for electrolysis. be able to. In the SOFC cell 1a and the SOEC cell 1b, the arrangement relationship between the anode electrodes (16a, 18b) and the cathode electrodes (16b, 18a) is reversed.

  The water supplied to the heating regenerator 10 through the flow path 22a is heated by the heating regenerator 10 to become water vapor and supplied from the flow path 22b to the flow path 20b. The water vapor supplied to the flow path 20b is further heated by the heat exchanger 4a, and then supplied to the cathode electrode 18a of the SOEC cell 1b through the flow path 20c.

In the cathode electrode 18a, water vapor receives electrons by the supplied electric power, and electrolysis is performed to generate hydrogen and oxygen ions (O ₂ − ions). Part of the generated hydrogen gas and the water vapor that did not generate hydrogen gas is supplied to the heat exchanger 4a through the flow path 20d. The generated oxygen ions are carried to the electrolyte 17 disposed between the cathode electrode 18a and the anode electrode 18b, and reach the anode electrode 18b while undergoing an exchange reaction with the electrolyte material. Here, oxygen ions are converted into oxygen and emit electrons. The generated oxygen is supplied to the heat exchanger 4b through the flow path 25c. The emitted electrons are supplied to the cathode electrode 18a and used for electrolysis of water vapor.

  Although heat is required for the electrolysis of water vapor in the SOEC cell 1b, the heat of the heat storage tank 2 storing the waste heat generated during power generation of the SOFC cell 1a can be used. In the heat exchanger 4a, the heat of the hydrogen gas and the water vapor emitted from the SOEC cell 1b is used to heat the water vapor supplied to the cathode electrode 18a of the SOEC cell 1b via the heat exchanger 4a. The

  The hydrogen gas and water vapor from which heat is extracted in the heat exchanger 4a obtains a propulsive force from the blower 5a provided in the flow path 20e, passes through the heating regenerator 10, and is supplied to the hydrogen separator 11 from the flow path 20f. The In the heating regenerator 10, heat obtained from the hydrogen gas and water vapor supplied through the flow path 20e can be used as a heat source for evaporating water. The hydrogen gas separated by the hydrogen separator 11 passes through the flow path 21b and is stored in the hydrogen tank 9. The water separated by the hydrogen separator 11 is discharged to the outside through the flow path 21a.

  The air supplied to the anode electrode 18b of the SOEC cell 1b obtains a propulsive force from the blower 5b provided in the flow path 25a and is supplied to the heat exchanger 4b. After being heated by the heat exchanger 4b, it is supplied to the SOEC cell 1b through the flow path 25b. Oxygen generated at the cathode electrode 18a of the SOEC cell 1b is supplied to the heat exchanger 4b through the flow path 25c together with air, and the heat of the oxygen and air supplied to the heat exchanger 4b is heat exchange. It is used to warm the air supplied to the anode electrode 18b of the SOEC cell 1b by the vessel 4b. Thereafter, the oxygen and air that have exited the heat exchanger 4b are released into the atmosphere. Alternatively, oxygen can be stored in an oxygen tank (not shown). The oxygen gas stored in the oxygen tank can be configured to be supplied to the cathode electrode 16b of the SOFC cell 1a.

Between the SOEC cell 1b and the heat storage tank 2, a circulation path 3 that circulates nitrogen gas as a heat medium is configured, and the heat stored in the heat storage tank 2 is circulated by circulating the nitrogen gas. Used for electrolysis of water vapor in cell 1b. The nitrogen gas discharged through the SOEC cell 1b is used for heating the nitrogen gas supplied to the heat storage tank 2 via the heat exchanger 4. A blower 5 for circulating nitrogen gas in the circulation path 3 is disposed in the circulation path 3.
In addition, the heat stored in the heat storage tank 2 can be used as a heat source for the heating regenerator 10 as necessary.

  As described above, in order to achieve high conversion efficiency, it is assumed that the heat generated in the SOFC cell 1a is used in the SOEC cell 1b. For this purpose, a heat storage device (heat storage tank 2) is used. Is needed.

  As a heat storage device, a method utilizing the latent heat of molten salt is considered, and nitrogen as a heat medium is placed between a heat storage tank in which capsules containing molten salt are arranged and a stack in which SOFC / SOEC cell 1 is laminated. By circulating gas, heat is transferred between the heat storage tank (heat storage tank 2) and the SOFC / SOEC cell 1.

JP 2010-176939 A

  As described above, in the power storage system, in order to exchange heat between the heat storage tank 2 and the SOFC / SOEC cell 1, it is necessary to circulate nitrogen gas through the circulation path 3. Moreover, the temperature of the nitrogen gas when it comes out of the heat storage tank 2 is as high as about 800 ° C., for example. As described in the background art section above, when a blower operating at 800 ° C. is used as the blower 5 used for circulating nitrogen gas, an expensive blower must be used.

  Therefore, using a blower 5 that operates at about 300 ° C, the temperature of the nitrogen gas supplied to the blower 5 using the heat exchanger 4 at 300 ° C to 800 ° C is lowered to 300 ° C, and the nitrogen gas is circulated. Employment is more realistic. In this case, there is a problem that the loss in the heat exchanger increases and the heat storage efficiency in the heat storage tank 2 decreases.

  This will be described with reference to FIG. 9 showing the configuration of the circulation path 3. The heat exchanger 4 is a heat exchanger of 300 ° C.-800 ° C., and its thermal efficiency is 95%. At this time, assuming that the temperature of the nitrogen gas exiting the heat storage tank 2 and entering the heat exchanger 4 is 800 ° C., the heat exchanger 4 has 95 %, That is, heat of 475 ° C. can be taken out through heat exchange. As a result, the temperature of the nitrogen gas when supplied to the blower 5 is 325 ° C.

  When 300 ° C. nitrogen gas is discharged from the blower 5, 300 ° C. nitrogen gas is supplied to the heat exchanger 4. In the heat exchanger 4, the heat of 475 ° C. that has been taken out by heat exchange is supplied, and the nitrogen gas heated to 775 ° C. is supplied to the SOFC cell 1a.

  As a result, the nitrogen gas temperature on the inlet side of the SOFC cell 1a is 25 ° C. lower than 800 ° C., which is the nitrogen gas temperature when leaving the heat storage tank 2 and entering the heat exchanger 4. Therefore, for example, even when there is a temperature difference of 40 ° C. between the inlet and outlet of the SOFC cell 1a, that is, the SOFC cell 1a in a state where the nitrogen gas is raised by 40 ° C. due to the waste heat of the SOFC cell 1a. Will come out of. Therefore, nitrogen gas comes out of the SOFC cell 1a at a temperature of 815 ° C., which is 40 ° C. higher than the temperature when the SOFC cell 1a is supplied at 775 ° C., and enters the heat storage tank 2 at a temperature of 815 ° C. Will be supplied.

  As a result, the heat storage tank 2 that can store up to 800 ° C can store heat for 15 ° C, which is the difference from 800 ° C, even though the nitrogen gas rose by 40 ° C in the SOFC cell 1a. As a result, only 37.5% of the increased 40 ° C will be used effectively. The remaining 62.5% will be discarded as heat exchanger loss.

For this reason, the heat storage efficiency is lowered, and there is a problem that the efficiency of the system is also lowered.
The above numerical values are exemplary numerical values used for explanation.

  The problem to be solved by the present invention is to provide a heat storage device having a heat medium circulation system with little heat exchange loss.

  The heat storage device according to the present embodiment includes a heat utilization device that performs a heat generation operation and a heat absorption operation, a heat storage tank that has a heat storage material that stores waste heat generated during the heat generation operation of the heat utilization device, the heat utilization device, and the heat utilization device. A heat medium circulation path that circulates a heat medium that passes through the heat storage tank and performs heat exchange between the heat utilization device and the heat storage tank, a heat exchanger provided in the heat medium circulation path, and the heat A heat storage device that circulates a medium in the heat medium circuit, wherein the heat medium circuit has a plurality of heat exchange channels that pass through the heat utilization device and the heat storage tank, The main feature is that the heat exchange channels are connected in series continuously.

  According to the embodiment of the present invention, a heat medium circulation system with little heat exchange loss can be obtained.

It is a whole arrangement block diagram of a thermal storage device. Example 1 It is a general arrangement configuration diagram of another heat storage device. (Example 2) It is explanatory drawing which shows the effect about the structure which made the heat insulating material common. (Example 2) It is a block diagram which shows a heat utilization apparatus, a thermal storage tank, and a flow path. (Example 2) It is a whole arrangement block diagram of another heat storage device. (Example 3) It is the whole arrangement block diagram of another heat storage device. Example 4 It is a whole block diagram in the electric power generation mode of a hydrogen power storage system. (Conventional example) It is a whole block diagram in the electrolysis mode of a hydrogen power storage system. (Conventional example) It is a figure explaining the heat loss of a heat exchanger. (Explanation) It is a whole arrangement block diagram which shows the modification of a heat carrier circuit. Example 1 It is a perspective view which shows the stack | stuck of a SOFC / SOEC cell. (Example 2)

Embodiments of the present invention will be specifically described below with reference to the accompanying drawings.
Examples 1 to 4 will be described with reference to FIGS. 1 to 6, 10, and 11. In each example, SOFC / SOEC cell 1 (solid oxide fuel cell / high temperature steam) An example of a configuration in the case where an electrolysis cell) is used as a SOFC cell 1a (solid oxide fuel cell) is shown. The overall system configuration using the SOFC cell 1a is the same as that described with reference to FIG.

  Therefore, about the structure similar to the structure demonstrated in FIG. 7, the overlapping description is abbreviate | omitted by using the member code | symbol used in FIG. Further, as the temperature of the heat medium before and after the heat exchanger 4, the temperature described in FIG. 9 is used.

In addition, the description will be made with a configuration using nitrogen gas (N ₂ gas) as a heat medium and a blower 5 operating at a temperature of about 300 ° C. as a circulation device. However, the heat medium is limited to nitrogen gas. However, carbon dioxide gas (CO ₂ gas), helium gas (He gas), or the like can also be used. The blower 5 is not limited to one that operates at a temperature of about 300 ° C. In this embodiment, it can be configured using an appropriate heat medium and blower that can be suitably applied.

  In the following, the case where the SOFC / SOEC cell 1 is used as the SOFC cell 1a will be described, but the present embodiment is preferably applied even when the SOFC / SOEC cell 1 is used as the SOEC cell 1b. be able to. In this case, the flow direction of nitrogen gas is reversed. Moreover, the piping of the flow path between the heat exchanger 4 and the blower 5 has the piping configuration shown in FIG.

  The configuration of Example 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, in the heat storage device according to the present embodiment, n heat exchange flow paths 3 a are formed between the stack of SOFC cells 1 a and the heat storage tank 2 as the nitrogen gas circulation path 3. . In the heat exchange channel 3a, waste heat generated in the SOFC cell 1a can be taken out using nitrogen gas, and the taken out heat can be stored in the heat storage tank 2.

  The temperature of the nitrogen gas flowing into the SOFC cell 1a from the heat exchanger 4 is 25 ° C. lower than the temperature of, for example, 800 ° C. when leaving the heat storage tank 2 due to heat exchange loss in the heat exchanger 4. It has become. Therefore, the temperature of the nitrogen gas when leaving the SOFC cell 1a is 815 ° C., which is increased by 40 ° C. due to waste heat in the SOFC cell 1a. Then, it flows into the heat storage tank 2 at a temperature of 815 ° C.

  As a result, the heat storage tank 2 that can store up to 800 ° C can store heat for 15 ° C, which is the difference from 800 ° C, even though the nitrogen gas rose by 40 ° C in the SOFC cell 1a. As a result, only 37.5% of the increased 40 ° C will be used effectively. The remaining 62.5% will be discarded as heat exchanger loss.

  In this embodiment, the nitrogen gas having a temperature of 800 ° C. exiting the heat storage tank 2 is guided to the entrance of the SOFC cell 1a through the flow path 3b. By repeating this, the nitrogen gas having a temperature of 800 ° C. exiting the heat storage tank 2 can flow between the SOFC cell 1a and the heat storage tank 2 through the heat exchange channel 3a n−1 times. it can. In addition, at this time, the temperature of the nitrogen gas flowing into the SOFC cell 1a is 800 ° C. from the heat storage tank 2, so that the temperature rises to 840 ° C. when leaving the SOFC cell 1a. Therefore, nitrogen gas can flow into the heat storage tank 2 at a temperature of 840 ° C., and a temperature of 40 ° C. can be stored in the heat storage tank 2.

  Since it is configured in this manner, in the embodiment of the present invention, the temperature at the inlet of the SOFC cell 1a is lowered as the temperature of the nitrogen gas due to the heat exchange loss of the heat exchanger 4 only in the first turn. From the second turn, the heat exchange loss disappears, so the heat exchange loss is reduced to 1 / n. In addition, the heat transfer amount per turn is 1 / n, and the flow rate of nitrogen gas is also 1 / n. Therefore, both the blower 5 and the heat exchanger 4 can be used in a small size, and the cost can be reduced.

  As described above, according to the embodiment of the present invention, the heat exchange loss of the heat exchanger 4 can be greatly reduced, and the blower 5 and the heat exchanger 4 can be reduced in size, and the cost is also reduced. Can be reduced.

  FIG. 1 shows a configuration in which the n heat exchange channels 3a are arranged linearly. However, for example, as shown in FIG. . By configuring in this way, the pipe lengths of the flow paths 3c, 3f connecting the heat exchanger 4, the SOFC cell 1a, and the heat storage tank 2 can be shortened.

The structure of Example 2 which concerns on embodiment of this invention is demonstrated using FIGS. 2-4, FIG. In addition, the same code | symbol is attached | subjected to the structure same as Example 1, and the overlapping description is abbreviate | omitted.
Example 2 has a configuration having a heat storage tank 2 containing a stack of SOFC cells 1a and a heat storage material. The SOFC cell 1a stack and the heat storage tank 2 are each divided into a plurality of parts, and one of the divided stacks and one of the divided heat storage tanks 2 are configured as a unit 30 surrounded by a thick line in FIG. .

Nitrogen gas is circulated through each unit cell 32 in which the circulation path 3 is arranged in series and further connected to the heat exchanger 4 and the blower 5. A plurality of unit cells 32 connected in series are covered with a heat insulating material 6. Further, as shown in FIG. 11, the SOFC / SOEC cell 1 stack has porous electrodes 21a and 21b made of, for example, platinum on both surfaces of a solid oxide electrolyte 22 made of ceramics such as stabilized zirconia, Further, conductive end plates 23a and 23b or a conductive separator plate 24 are arranged on the other surface side of the porous electrodes 21a and 21b.
The end plates 23a and 23b and the separator plate 24 can be made of thick copper plates or the like.

  A unit cell 32 is formed between the end plates 23a, 23b and the adjacent separator plate 24 or between the adjacent separator plates 24. For example, a stack of SOFC / SOEC cells 1 is formed by stacking a plurality of the unit cells 32. The current A in the SOFC / SOEC cell 1 flows in the unit cell stacking direction.

  The end plates 23a and 23b and the separator plate 24 are formed with an air flow path 25 and a fuel gas flow path 26 so that the fuel gas and air flow in directions orthogonal to each other, and the heat exchange flow path 3a It is provided to form a one-through configuration.

As shown in FIG. 4, the heat storage tank 2 has a configuration in which a plurality of cylindrical capsules containing molten salt are arranged and covered with an airtight container 31. A cylindrical capsule is configured as the heat storage material 8. Nitrogen gas flows between the airtight container 31 and the heat storage material 8. The hermetic container 31 and the heat exchange flow path 3a are hermetically connected to form a nitrogen gas flow path for exchanging heat with the SOFC / SOEC cell 1.
The unit 30 described above will be further described. The unit 30 is configured by combining the unit cell 32 in the SOFC / SOEC cell 1 with the heat storage tank 2.

  As shown in FIG. 2, the nitrogen gas obtained by the blower 5 is heated by the heat exchanger 4, and then the unit cell 32 → the heat storage tank 2 → the unit cell 32 →. , Is returned to the heat exchanger 4 and cooled, and then supplied to the blower 5. Also in this case, as in Example 1, the temperature of nitrogen gas at the inlet of the unit cell 32 is reduced by the heat exchange loss of the heat exchanger only in the first turn, but no heat exchange loss occurs from the second turn. Exchange loss is reduced to 1 / n.

  Further, the flow rate of nitrogen gas is also reduced to 1 / n, and both the blower 5 and the heat exchanger 4 can be accommodated with a small configuration, thereby reducing the cost. Further, in the first embodiment, the pressure loss of the piping in the circulation path 3 is large and the number of turns is limited. However, in the configuration shown in the second embodiment, the increase in pressure loss is small and the number of turns can be increased. Therefore, the flow rate of nitrogen gas can be greatly reduced. In addition, since it is not necessary to route the piping as the circulation path 3, a compact configuration can be achieved.

  Moreover, as shown on the left side of FIG. 3, the heat insulating material 6 for the heat storage tank 2 and the heat insulating material 6 for the SOFC / SOEC cell 1 were separately required, but the heat storage tank 2 and the unit cell 32 were united. By integrally configuring as 30, it is possible to configure the heat insulating material 6 in an integrated state as shown on the right side of FIG.

  In particular, in a hydrogen power storage system using the SOFC / SOEC cell 1, it is necessary to increase the heat storage efficiency in order to maintain high efficiency, and furthermore, since a high temperature of 800 ° C. is stored, the heat insulating layer as the heat insulating material 6 It is necessary to make the thickness of the thicker. In Example 2 of the present invention, since the heat insulating material 6 can be integrated as described above, the entire volume is significantly reduced by integrating the heat insulating material 6. And the area which arrange | positions a hydrogen power storage system can be decreased.

  As shown in FIG. 11, the stack configuration of the SOFC / SOEC cell 1 includes a fuel gas passage 26 to which hydrogen gas and water vapor are supplied, an air passage 25 to which air is supplied, and porous electrodes 21a and 21b. This configuration is a unit cell 32 configuration. A stack of SOFC / SOEC cells 1 is configured by connecting adjacent unit cells 32 to each other.

  Therefore, it is difficult to route the heat exchange flow path 3a around each unit cell 32. In addition, there is a method of cooling from both ends of the SOFC / SOEC cell 1 stack when heat is generated in the SOFC cell 1a, but the temperature gradient in the SOFC / SOEC cell 1 stack is large due to the large amount of heat generated in the unit cell 32. Will occur.

  The characteristics of the stack of the SOFC / SOEC cell 1 are highly temperature dependent, and the characteristics of the unit cells 32 in the stack of the SOFC / SOEC cell 1 will vary.

  According to the configuration of the second embodiment of the present invention, the amount of heat transfer in each of the thick copper plates constituting the end plates 23a and 23b and the separator plate 24 is reduced, and the heat transfer distance is also reduced, thereby reducing temperature variations. And good characteristics can be obtained.

  Moreover, according to the structure of Example 2 of this invention, the heat exchange loss of a heat exchanger can be reduced significantly. As a result, the blower 5 and the heat exchanger 4 can be reduced in size and the cost can be reduced. In addition, the stack of SOFC / SOEC cell 1 can be operated under good characteristics.

The configuration of Example 3 according to the embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the structure same as Example 1, 2, and the overlapping description is abbreviate | omitted.
In Example 3, the stack of SOFC / SOEC cell 1 is divided into SOFC cell 1a and SOEC cell 1b, and unit 30 is configured in the order of SOFC cell 1a-heat storage tank 2-SOEC cell 1b. It is a configuration connected in series.

  With this configuration, when the required capacities of the SOFC cell 1a and the SOEC cell 1b are different depending on the operating conditions, the required capacities of the respective capacities can be changed.

  For example, the SOEC cell 1b needs to convert a large current in a short time due to short-term fluctuations in wind power generation, but the SOFC cell 1a may output a long time with a small current. Further, the heat flow flows from the SOFC cell 1a to the heat storage tank 2 during power generation, and flows from the heat storage tank 2 to the SOEC cell 1b during electrolysis.

  By configuring as in the third embodiment, the flow direction of nitrogen gas can always be one direction, and there is no need to switch the flow direction. For this reason, the piping configuration of the circulation path 3 is simplified and the cost is reduced. Further, even if a solenoid valve (not shown) for adjusting the flow rate of nitrogen gas is provided in the circulation path 3, the problem of the solenoid valve is eliminated and the reliability is improved.

  Thus, according to the configuration of the third embodiment of the present invention, even when the current capacities during power generation using the SOFC cell 1a and during electrolysis using the SOEC cell 1b are different, they can be efficiently handled. It is possible to simplify the piping configuration of the circulation path 3 for circulating the nitrogen gas, and a highly reliable heat storage device can be obtained.

The configuration of Example 4 according to the embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the structure same as Examples 1-3, and the overlapping description is abbreviate | omitted.
In Example 4, the stack of SOFC / SOEC cell 1 is divided into SOFC cell 1a and SOEC cell 1b, and a plurality of sets of heat storage tank 2-SOEC cell 1b are formed, SOFC cell 1a-heat storage tank 2-SOEC cell 1b-- The unit 35 is configured in the order of the heat storage tank 2-SOEC cell 1b. A plurality of units 35 are connected in series.
FIG. 6A shows the flow of nitrogen gas in the SOFC cell 1a mode with an arrow, and FIG. 6B shows the flow of nitrogen gas in the SOEC cell 1b mode with an arrow.

  With this configuration, as described in the third embodiment, it is possible to share components even when the capacity of the stack of the SOFC cell 1a and the stack of the SOEC cell 1b is ½. Further, since the required flow rate of the nitrogen gas to be circulated can be adjusted at the time of power generation with a low flow rate, the blower 5 and the heat exchanger 4 can be reduced in size and cost.

  In addition, although the structure which repeated the combination of the thermal storage tank 2-SOEC cell 1b twice is shown as a structural example of Example 4, it can also be set as the structure repeated 3 times or more. If the current capacity during power generation is large, the SOFC cell 1a-heat storage tank 2 combination may be arranged multiple times.

  In the embodiment of the present invention, a plurality of heat exchange channels that pass through the heat utilization device and the heat storage tank are provided, and the plurality of heat exchange channels are connected in series in a continuous state. By using the heat exchanger that lowers the temperature of the heat medium supplied to the circulation device and raises the temperature of the heat medium flowing into the heat utilization device, a loss based on the heat efficiency of the heat exchanger occurs as described above. . Due to this loss, the temperature of the heat medium flowing from the heat exchanger into the heat utilization device becomes lower than the temperature when flowing from the heat storage tank to the heat exchanger.

  However, in the embodiment of the present invention, the heat medium that has passed through the heat exchanger and transferred heat in the heat storage tank is configured to continuously flow into the heat utilization device again. Moreover, when the heat medium continues to flow into the heat utilization apparatus again, the heat medium can flow into the heat utilization apparatus at a temperature that has left the heat storage tank.

  Since the heat medium that has flowed out of the heat storage tank can flow again through the heat utilization device a plurality of times, that is, the number of heat exchange channels formed can be reflowed into the heat utilization device, the second turn After that, the temperature of the heat medium flowing into the heat utilization device is always the temperature that is left from the heat storage tank, and no temperature drop occurs.

  As a result, the heat loss can be reduced to 1 / n in the embodiment of the present invention as compared with the case of flowing through the heat utilization apparatus only once. Moreover, since the heat transfer amount in one turn is 1 / n, the nitrogen gas flow rate can also be reduced to 1 / n. As described above, in the embodiment of the present invention, both the circulation device and the heat exchanger can use small-sized devices, so that the cost can be reduced.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, combinations, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... SOFC / SOEC cell stack, 1a ... SOFC cell stack, 1b ... SOEC cell stack, 2 ... Heat storage tank, 3 ... Circulation path, 3a ... Heat exchange flow path, 3b-3f ... Flow path, 4 ... Heat Exchanger, 5 ... Blower, 6 ... Heat insulation, 7 ... Heat transfer block, 8 ... Heat storage material, 9 ... Hydrogen tank, 10 ... Heat storage, 11 ... Hydrogen separator, 14a, 14b ... Heat exchanger, 15a, 15b ... Blower, 16a, 18b ... Anode electrode, 16b, 18a ... Cathode electrode, 17 ... Electrolyte, 20 ... Heat storage device, 21a, 21b ... Porous electrode, 22 ... Electrolyte, 23a, 23b ... End plate, 24 ... Separator plate , 25 ... air passage, 26 ... fuel gas flow path, 30, 35 ... unit, 31 ... airtight container, 32 ... unit cell.

Claims (8)

A heat storage device having a heat storage device that performs heat generation operation and heat absorption operation; and a heat storage tank that stores waste heat generated during the heat generation operation of the heat utilization device and supplies heat stored in the heat storage material during the heat absorption operation; A heat medium circulation path that circulates a heat medium that exchanges heat between the heat utilization apparatus and the heat storage tank through the heat utilization apparatus and the heat storage tank, and heat exchange provided in the heat medium circulation path In a heat storage device having a storage device, and a circulation device that circulates the heat medium in the heat medium circulation path,
The heat medium circuit has a plurality of heat exchange channels that pass through the heat utilization device and the heat storage tank,
Each said heat exchange flow path is connected in series continuously, The heat storage apparatus characterized by the above-mentioned. A heat storage device having a heat storage device that performs heat generation operation and heat absorption operation; and a heat storage tank that stores waste heat generated during the heat generation operation of the heat utilization device and supplies heat stored in the heat storage material during the heat absorption operation; A heat medium circulation path that circulates a heat medium that exchanges heat between the heat utilization apparatus and the heat storage tank through the heat utilization apparatus and the heat storage tank, and heat exchange provided in the heat medium circulation path In a heat storage device having a storage device, and a circulation device that circulates the heat medium in the heat medium circulation path,
The heat utilization device and the heat storage tank are each composed of a plurality of heat utilization unit parts and a plurality of heat accumulation unit parts,
A heat storage device, characterized in that a heat exchange flow path is formed through a plurality of units in which the heat utilization unit and the heat storage unit are combined in series. The heat utilization unit is composed of a plurality of heat generating portions and a plurality of heat absorbing portions,
The heat storage device according to claim 2, wherein the unit has a configuration in which the heat generation portion, the heat storage unit portion, and the heat absorption portion are combined in series. The heat utilization unit is composed of a plurality of heat generating portions and a plurality of heat absorbing portions,
The heat storage according to claim 2, wherein the unit has a configuration in which the heat generating portion and a plurality of heat storage endothermic sets in which the heat storage unit portion and the heat absorption portion are combined in series are combined in series. apparatus. The heat utilization unit is composed of a plurality of heat generating portions and a plurality of heat absorbing portions,
3. The unit according to claim 2, wherein the unit has a configuration in which a plurality of exothermic heat storage units in which the exothermic part and the heat storage unit are combined in series and the endothermic part are combined in series. Thermal storage device. The heat utilization device is configured by stacking a plurality of flat cells sandwiched between a pair of heat transfer blocks,
The heat storage device according to any one of claims 1 to 5, wherein the heat exchange channel is formed in each of the heat transfer blocks.   The heat storage device according to any one of claims 1 to 6, wherein the heat utilization device and the heat storage tank are covered with an integrally configured heat insulating material.   The heat storage device according to any one of claims 1 to 7, wherein the heat utilization device is a solid oxide fuel cell / high temperature steam electrolysis cell using a solid oxide cell.

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