JP6906432B2 - Heat storage system - Google Patents

Description

The present invention relates to a heat storage system including a fuel cell device, a thermoacoustic refrigeration device, and a heat storage tank capable of storing heat using a heat storage medium.

A cogeneration system equipped with a fuel cell device realizes high overall efficiency of the entire system by effectively utilizing the exhaust heat (heat) generated during power generation by the fuel cell device. At this time, there is a system in which the heat discharged from the fuel cell device is stored in a heat storage tank and the stored heat is consumed by a heating device or the like.
However, since the heat demand in other seasons, especially in summer, is smaller than the heat demand in winter, it is possible that the heat stored in the heat storage tank is not consumed so much. In that case, the exhaust heat of the fuel cell device cannot be effectively used.

Patent Document 1 describes a system capable of converting hot heat discharged from a fuel cell device into cold heat and supplying it in a season such as summer when there is a large demand for cold heat. Specifically, a system that converts hot heat discharged from a fuel cell device into cold heat using a thermoacoustic refrigeration device that utilizes a thermoacoustic phenomenon is described.

Japanese Patent No. 6133998

In the system described in Patent Document 1, since the heat discharged from the fuel cell device can be stored in the heat storage tank, sufficient heat can be supplied for the heat application even at the timing when the heat demand becomes large. However, since cold heat cannot be stored, there is a possibility that sufficient cold heat cannot be supplied from the fuel cell device for cooling applications or the like at the timing when the cold heat demand increases.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a heat storage system capable of storing heat discharged from a fuel cell device in both hot and cold states.

The characteristic configuration of the heat storage system according to the present invention for achieving the above object includes a fuel cell device, a thermoacoustic refrigeration device, and a heat storage tank capable of storing heat using a heat storage medium.
The thermoacoustic refrigeration apparatus has a loop tube formed in an annular shape and filled with an operating medium inside, and exhaust heat that is provided in the middle of the loop tube and retains heat discharged from the low temperature side and the fuel cell apparatus. A first conversion unit that generates acoustic energy by a temperature gradient between the heat energy of the medium and the high temperature side to which the heat energy is supplied, and a first conversion unit that is provided in the middle of the loop tube and propagates from the first conversion unit through the loop tube. A heat storage system having a second conversion unit that can discharge cold heat from the low temperature side to the outside by utilizing the temperature gradient generated between the low temperature side and the high temperature side by converting the generated acoustic energy into heat energy. There,
The heat storage tank can store the heat storage medium inside in a state of forming a temperature stratification in which the upper part is relatively high temperature and the lower part is relatively low temperature, and the heat storage tank is provided with an upper port provided on the upper side of the heat storage tank. The heat storage medium is configured to flow inside and outside the heat storage tank via a lower port provided on the lower side.
When performing a heat storage operation for newly storing the heat storage medium having a relatively high temperature in the heat storage tank, the heat storage medium taken out from the lower port of the heat storage tank is heated by the exhaust medium, and then the heat storage medium is stored. Flowing so that it returns to the upper port of the heat storage tank,
When performing a cold heat storage operation in which the heat storage medium having a relatively low temperature is newly stored in the heat storage tank, the heat storage medium taken out from the upper port of the heat storage tank is cooled by the second conversion unit of the thermoacoustic refrigeration apparatus. After that, the heat storage medium is flowed so as to return to the lower port of the heat storage tank .
A fluid circulation path through which a fluid can circulate between the first conversion unit and the second conversion unit is provided.
When performing the cold heat storage operation
A fluid is circulated between the first conversion unit and the second conversion unit through the fluid circulation path.
By supplying the exhaust heat medium to the first high temperature side heat exchange unit constituting the high temperature side of the first conversion unit, the first high temperature side heat exchange unit is made relatively hot, and the first conversion unit By supplying the fluid circulating in the fluid circulation path to the first low temperature side heat exchange section constituting the low temperature side, the first low temperature side heat exchange section is relatively cooled, and the first high temperature side heat exchange section is used. And the acoustic energy is generated by the temperature gradient generated by the first low temperature side heat exchange unit.
In a state where the acoustic energy is propagated from the first conversion unit to the second conversion unit through the loop tube, the fluid circulation to the second high temperature side heat exchange unit constituting the high temperature side of the second conversion unit. The fluid circulating in the path is supplied, and the heat storage medium taken out from the upper port of the heat storage tank is supplied to the second low temperature side heat exchange section constituting the low temperature side of the second conversion section to supply the working medium. The point is that the heat storage medium taken out from the upper port of the heat storage tank is cooled by the second low temperature side heat exchange section due to the temperature gradient generated by converting the acoustic energy into heat energy .

According to the above characteristic configuration, in the heat storage system, the heat discharged from the fuel cell device can be stored in the heat storage tank in a hot state by the heat storage operation, and the cold heat is stored by the cold heat storage operation using the thermoacoustic refrigeration device. It can be stored in the heat storage tank in the state.
Therefore, it is possible to provide a heat storage system capable of storing the heat discharged from the fuel cell device in both hot and cold states.
Further, according to the above-mentioned feature configuration, when the cold heat storage operation is performed, the first conversion unit supplies the exhaust heat medium to the first high temperature side heat exchange unit constituting the high temperature side, thereby exchanging the first high temperature side heat. The first low temperature side heat exchange section is made relatively low temperature by supplying the fluid circulating in the fluid circulation path to the first low temperature side heat exchange section constituting the low temperature side. The acoustic energy is generated by the temperature gradient generated by the first high temperature side heat exchange section and the first low temperature side heat exchange section. That is, in the first conversion unit, thermal energy can be converted into acoustic energy.
Further, when the cold heat storage operation is performed, in the second conversion unit, the acoustic energy is propagated from the first conversion unit to the second conversion unit through the loop tube, and the second high temperature side constituting the high temperature side thereof is formed. A fluid circulating in the fluid circulation path is supplied to the heat exchange section, and a heat storage medium taken out from the upper port of the heat storage tank is supplied to the second low temperature side heat exchange section constituting the low temperature side, so that the acoustic energy of the working medium is generated. Due to the temperature gradient generated by the conversion into heat energy, the heat storage medium taken out from the upper port of the heat storage tank can be cooled by the second low temperature side heat exchange section, and the cold heat can be stored in the heat storage tank.
That is, in the second conversion unit, acoustic energy can be converted into thermal energy.

Another characteristic configuration of the heat storage system according to the present invention is that the fuel cell device is supplied with a reforming unit that steam-reforms raw fuel to generate fuel gas and the fuel gas generated by the reforming unit. Combustion that burns the fuel component in the exhaust fuel gas discharged from the anode after being used in the power generation reaction in the fuel cell section and the fuel cell section having the anode and the cathode to which the oxygen gas is supplied. Has a part and
When the heat storage operation is performed, the combustion exhaust gas discharged from the combustion unit is used as the heat exhaust medium, and the heat energy of the heat storage medium is used to heat the heat storage medium taken out from the lower port of the heat storage tank. Consume and
When the cold heat storage operation is performed, the combustion exhaust gas discharged from the combustion unit is used as the exhaust heat medium, and the heat energy of the exhaust heat medium is consumed to heat the high temperature side of the first conversion unit.
The point is that condensed water is recovered from the combustion exhaust gas whose temperature has decreased due to heat energy consumption, and the condensed water is used for steam reforming of raw fuel in the reforming section.

According to the above characteristic configuration, when the heat storage operation is performed, the heat energy possessed by the combustion exhaust gas discharged from the combustion part of the fuel cell device is consumed to heat the heat storage medium taken out from the heat storage tank. Further, when the cold heat storage operation is performed, the thermal energy possessed by the combustion exhaust gas discharged from the combustion portion of the fuel cell apparatus is consumed to heat the high temperature side of the first conversion portion of the thermoacoustic refrigeration apparatus. That is, in both the hot storage operation and the cold storage operation, the combustion exhaust gas is cooled by depriving the combustion exhaust gas of heat energy, and the water contained in the combustion exhaust gas is condensed. As a result, the condensed water can be recovered as water that can be used for steam reforming of the raw material and fuel in the reforming section.

Yet another characteristic configuration of the heat storage system according to the present invention is that a radiator capable of adjusting the amount of heat radiated from the fluid per unit time is provided in the middle of the fluid circulation path.

According to the above characteristic configuration, the amount of heat radiated from the fluid flowing through the fluid circulation path can be adjusted to lower the temperature of the fluid. That is, by lowering the temperature of the first low temperature side heat exchange section to which the fluid flowing through the fluid circulation path is supplied, it is possible to sufficiently secure the temperature difference between the low temperature side and the high temperature side of the first conversion section. Further, by lowering the temperature of the second high temperature side heat exchange section to which the fluid flowing through the fluid circulation path is supplied, the temperature of the high temperature side of the second conversion section is lowered, and the low temperature side of the second conversion section is configured. The heat storage medium taken out from the upper port of the heat storage tank supplied to the second low temperature side heat exchange unit can be cooled to a low temperature.

Yet another characteristic configuration of the heat storage system according to the present invention is that when the cold heat storage operation is performed, the radiator is used so that the temperature of the second low temperature side heat exchange unit becomes 0 ° C. or higher. The point is to adjust the amount of heat released per unit time from the fluid flowing through the fluid circulation path.

According to the above characteristic configuration, the amount of heat radiated from the fluid flowing through the fluid circulation path is adjusted by the radiator, and the temperatures of the first low temperature side heat exchange section and the second high temperature side heat exchange section to which the fluid is supplied are adjusted. can do. That is, the temperature of the second low temperature side heat exchange unit, which changes according to those temperatures, can also be adjusted by the operation of the radiator. Therefore, by adjusting the amount of heat radiated from the fluid flowing through the fluid circulation path per unit time so that the temperature of the second low temperature side heat exchange section becomes 0 ° C. or higher, the water content in the second low temperature side heat exchange section is reduced. It is possible to avoid freezing.

Yet another characteristic configuration of the heat storage system according to the present invention includes a flow velocity regulator capable of adjusting the flow velocity of the fluid flowing through the fluid circulation path.
When the cold heat storage operation is being performed, the flow velocity regulator adjusts the flow velocity of the fluid flowing through the fluid circulation path so that the temperature of the second low temperature side heat exchange section becomes 0 ° C. or higher. be.

According to the above characteristic configuration, the flow velocity of the fluid flowing through the fluid circulation path can be adjusted by the flow velocity controller, and the temperatures of the first low temperature side heat exchange section and the second high temperature side heat exchange section to which the fluid is supplied can also be adjusted. .. Therefore, by adjusting the operation of the flow velocity regulator so that the second low temperature side heat exchange section becomes 0 ° C. or higher, it is possible to prevent the water from freezing in the second low temperature side heat exchange section.

Yet another characteristic configuration of the heat storage system according to the present invention is that the heat storage medium taken out from the heat storage tank does not pass through the second low temperature side heat exchange section, but instead of the first high temperature side heat exchange section. The heat recovery flow path that flows after passing through and before returning to the heat storage tank,
The heat storage medium taken out from the heat storage tank does not pass through the first high temperature side heat exchange section, but flows through the second low temperature side heat exchange section until it returns to the heat storage tank. The point is that it is provided with a flow path for cold heat recovery.

According to the above characteristic configuration, when the heat storage operation is performed, the heat storage medium taken out from the heat storage tank is flowed through the heat recovery flow path, so that the heat storage medium is heated in the first high temperature side heat exchange section in the middle. can.
Further, when the cold heat storage operation is performed, the heat storage medium taken out from the heat storage tank is allowed to flow through the cold heat recovery flow path, so that the heat storage medium can be cooled in the second low temperature side heat exchange section on the way.

Yet another characteristic configuration of the heat storage system according to the present invention includes a fluid circulation path through which a fluid can circulate between the first conversion unit and the second conversion unit.
When the heat storage operation is performed, the heat storage medium taken out from the lower port of the heat storage tank is heated by the exhaust medium in the first high temperature side heat exchange unit constituting the high temperature side of the first conversion unit. The point is to allow the heat storage medium to flow so as to return to the upper port of the heat storage tank.

According to the above characteristic configuration, when the heat storage operation is performed, the heat storage medium taken out from the lower port of the heat storage tank is heated by the exhaust heat medium in the first high temperature side heat exchange unit constituting the high temperature side of the first conversion unit. After that, the heat storage medium can be flowed so as to return to the upper port of the heat storage tank, so that the heat can be stored in the heat storage tank.

Yet another characteristic configuration of the heat storage system according to the present invention is that the heat exhaust medium after heat exchange is performed in the first high temperature side heat exchange section and the fluid circulation path flow in the middle of the fluid circulation path. The point is that it is provided with a heat exchange unit that exchanges heat with a fluid.

According to the above-mentioned characteristic configuration, further heat can be taken from the heat exhaust medium holding the heat discharged from the fuel cell device by using the heat exchange unit. That is, the heat exhaust medium can be further cooled by using this heat exchange unit. Therefore, when the exhaust heat medium is a combustion exhaust gas, the water contained in the combustion exhaust gas can be sufficiently recovered.

It is the schematic which shows the structure of the heat storage system. It is a figure which shows the structure of the heat storage system of 1st Embodiment. It is a figure explaining the thermal storage operation. It is a figure explaining the cold heat storage operation. It is a figure which shows the structure of the heat storage system of 2nd Embodiment. It is a figure explaining the thermal storage operation in the heat storage system of a reference form. It is a figure explaining the cold heat storage operation in the heat storage system of a reference form. It is a figure which shows the thermoacoustic refrigerating apparatus of another structure.

<First Embodiment>
The heat storage system according to the first embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic view showing the configuration of a heat storage system. FIG. 2 is a diagram showing the configuration of the heat storage system of the first embodiment. As shown in FIG. 1, the heat storage system includes a fuel cell device 20, a thermoacoustic refrigerating device 30, and a heat storage tank 1 capable of storing heat using a heat storage medium.

The fuel cell device 20 is not only a power supply device that generates electric power but also a heat source device that generates heat. The fuel cell device 20 shown in FIG. 2 has a reforming unit 23, a fuel cell unit 50 having an anode 24 and a cathode 25, and a combustion unit 27. In the fuel cell unit 50, an electrolyte unit 26 is provided between the anode 24 and the cathode 25. For example, the fuel cell unit 50 is a solid oxide fuel cell. In the example shown in FIG. 2, a raw material fuel gas containing a hydrocarbon such as city gas is supplied to the reforming unit 23 through the raw material fuel supply path 21. Further, the reforming unit 23 is supplied with reforming water from the water tank 3 for storing condensed water through the water supply path 22. The raw fuel gas is steam reformed in the reforming section 23, and the generated hydrogen-based fuel gas is supplied to the anode 24 of the fuel cell section 50. Further, oxygen (air) is supplied to the cathode 25 of the fuel cell unit 50 through the air supply path 28. In the power generation reaction in the fuel cell unit 50, not all hydrogen is consumed, and the fuel component remains in the discharged anode gas discharged from the anode 24. After that, the combustion unit 27 burns the fuel component in the exhaust fuel gas discharged from the anode 24. Then, the combustion heat generated in the combustion unit 27 is supplied to, for example, the reforming unit 23. When the fuel cell device 20 includes the solid oxide fuel cell unit 50, the temperature of the combustion exhaust gas is, for example, 160 ° C. As will be described later, in the present embodiment, condensed water is recovered from the combustion exhaust gas by cooling the combustion exhaust gas discharged from the combustion unit 27 (recovering heat energy), and the condensed water is collected by the reforming unit 23. Used for steam reforming of raw materials and fuels. In the example shown in FIG. 2, the condensed water flows into the water tank 3 through the water recovery path 2 connected so as to branch from the combustion exhaust gas path 29.
The operation of the fuel cell device 20 is controlled by the control device C.

As shown in FIGS. 1 and 2, the thermoacoustic refrigerating apparatus 30A (30) is provided in a loop tube 39 formed in an annular shape and filled with an operating medium, and a low temperature side provided in the middle of the loop tube 39. A first conversion unit 34 that generates acoustic energy by a temperature gradient between the heat energy of the exhaust heat medium holding the heat discharged from the fuel cell device 20 and the high temperature side to which the heat energy is supplied is provided in the middle of the loop pipe 39. Then, the acoustic energy propagated from the first conversion unit 34 through the loop tube 39 is converted into heat energy, and the temperature gradient generated between the low temperature side and the high temperature side is used to from the low temperature side to the outside. It has a second conversion unit 38 capable of discharging cold heat. In the present embodiment, the combustion exhaust gas discharged from the combustion unit 27 of the fuel cell device 20 serves as a heat exhaust medium. The loop tube 39 is filled with an inert gas such as nitrogen or helium.

The first conversion unit 34 includes a first high temperature side heat exchange unit 31 constituting a high temperature side, a first low temperature side heat exchange unit 33 constituting a low temperature side, a first high temperature side heat exchange unit 31 and a first low temperature. It has a first stack 32 provided between the side heat exchange portions 33. The second conversion unit 38 includes a second high temperature side heat exchange unit 35 constituting a high temperature side, a second low temperature side heat exchange unit 37 constituting a low temperature side, a second high temperature side heat exchange unit 35, and a second low temperature. It has a second stack 36 provided between the side heat exchange portions 37. In the first stack 32 and the second stack 36, a plurality of thin plates made of stainless steel or the like are provided in a loop pipe 39 at minute intervals in a lattice shape or a honeycomb shape, so that a plurality of minute passages are parallel to each other. It has a formed structure.

The heat storage tank 1 can store the heat storage medium inside in a state of forming a temperature stratification in which the upper part is relatively high temperature and the lower part is relatively low temperature, and the heat storage tank 1 is provided with an upper port 40 provided on the upper side of the heat storage tank 1. It is configured so that the heat storage medium can flow inside and outside the heat storage tank 1 through the lower ports 41 and 42 provided on the lower side. For example, water as a heat storage medium is stored in the heat storage tank 1.

As shown in FIG. 2, the heat storage system includes a fluid circulation path 44 through which a fluid can circulate between the first conversion unit 34 and the second conversion unit 38. In this embodiment, water is used as the fluid. In addition, a radiator 45 capable of adjusting the amount of heat radiated from the fluid per unit time is provided in the middle of the fluid circulation path 44. A pump P3 is provided as a flow velocity adjuster capable of adjusting the flow velocity of the fluid flowing through the fluid circulation path 44. The radiator 45 includes a heat radiating fan 45a, and by adjusting the rotation speed of the heat radiating fan 45a, the amount of heat radiated from the fluid per unit time can be adjusted.
The operation of the pump P3 and the radiator 45 is controlled by the control device C.

In the heat storage system of the present embodiment, the heat storage medium stored in the heat storage tank 1 can be circulated through the heat storage medium flow path 43. The heat storage medium flow path 43 has a heat recovery flow path 43a, a cold heat recovery flow path 43b, and a common flow path 43c. Then, the heat storage medium stored in the heat storage tank 1 can be switched between a flow state in which the heat storage medium is taken out from the upper port 40 and returned to the lower port 42 and a flow state in which the heat storage medium is taken out from the lower port 41 and returned to the upper port 40. can.

When the heat storage medium stored in the heat storage tank 1 is taken out from the upper port 40 and returned to the lower port 42, the three-way valve V1 is switched so that it can be circulated through BC, and the pump P1 operates. Will be done. As a result, the heat storage medium taken out from the upper port 40 of the heat storage tank 1 to the common flow path 43c reaches the cold heat recovery flow path 43b through the three-way valve V1 and passes through the second low temperature side heat exchange section 37. Then, it returns to the lower port 42 of the heat storage tank 1. On the other hand, when the heat storage medium stored in the heat storage tank 1 is taken out from the lower port 41 and returned to the upper port 40 in a flowing state, the three-way valve V1 is switched so that it can be distributed by AC and is also available. Pump P2 is activated. As a result, the heat storage medium taken out from the lower port 41 of the heat storage tank 1 to the heat recovery flow path 43a passes through the first high temperature side heat exchange section 31 and the three-way valve V1 and the common flow path 43c to store heat. Return to the upper port 40 of the tank 1.
The operation of the pump P1, the pump P2, and the three-way valve V1 is controlled by the control device C.

As described above, in the present embodiment, the heat storage medium taken out from the heat storage tank 1 does not pass through the second low temperature side heat exchange unit 37, but passes through the first high temperature side heat exchange unit 31, and then the heat storage tank. The heat recovery flow path 43a that flows before returning to 1 and the heat storage medium taken out from the heat storage tank 1 do not pass through the first high temperature side heat exchange unit 31, but the second low temperature side heat exchange unit 37. A cold heat recovery flow path 43b that flows before returning to the heat storage tank 1 after passing through the above is provided separately.

The heat storage tank 1 can store hot and cold heat as described later, and the hot and cold heat can be output to the outside of the heat storage system. In the present embodiment, the upper connecting path 6 is connected to the upper side of the heat storage tank 1, and the lower connecting path 7 is connected to the lower side. Further, the upper connecting path 6 and the lower connecting path 7 are both connected to the water supply path 4 and the heat output path 5. Specifically, the upper connecting passage 6 is connected to the water supply passage 4b and the heat output passage 5a, and the lower connecting passage 7 is connected to the water supply passage 4a and the heat output passage 5b.

Then, when the three-way valve V2 is switched so that it can be circulated through AC and the three-way valve V3 is switched so that it can be circulated through AC, the water supplied through the water supply channel 4 is the three-way valve V3. It reaches the water supply channel 4a via the above, and then flows into the inside of the heat storage tank 1 from below the heat storage tank 1 through the lower connecting path 7. Further, the water inside the heat storage tank 1 is taken out through the upper connecting path 6, and is directed from the heat output path 5 toward the heat load device (not shown) via the heat output path 5a and the three-way valve V2. Be supplied.
On the other hand, when the three-way valve V2 is switched so that it can be circulated through BC and the three-way valve V2 is switched so that it can be circulated through BC, the water supplied through the water supply channel 4 is three-way. It reaches the water supply channel 4b via the valve V3, and then flows into the inside of the heat storage tank 1 from above the heat storage tank 1 through the upper connecting path 6. Further, the water inside the heat storage tank 1 is taken out through the lower connecting path 7, and is directed from the heat output path 5 to the heat load device (not shown) via the heat output path 5b and the three-way valve V2. Is supplied.
The operation of the three-way valve V2 and the three-way valve V3 is controlled by the control device C.

[Heat accumulation operation]
FIG. 3 is a diagram for explaining the thermal storage operation, and the flow of gas and each medium is highlighted with a thick line. When performing a heat storage operation in which a relatively high temperature heat storage medium is newly stored in the heat storage tank 1, the heat storage medium taken out from the lower port 41 of the heat storage tank 1 is heated by the exhaust heat medium, and then the heat storage medium is stored in the heat storage tank 1. It is made to flow so as to return to the upper port 40 of.
That is, when performing the heat storage operation, the combustion exhaust gas discharged from the combustion unit 27 is used as an exhaust heat medium, and the heat energy of the exhaust heat medium is used to heat the heat storage medium taken out from the lower port 41 of the heat storage tank 1. Consume. Specifically, during the heat storage operation, the lower port of the heat storage tank 1 is the first high temperature side heat exchange unit 31 that does not circulate the fluid in the fluid circulation path 44 and constitutes the high temperature side of the first conversion unit 34. After the heat storage medium taken out from 41 is heated by the exhaust heat medium (combustion exhaust gas), the heat storage medium is fluidized so as to return to the upper port 40 of the heat storage tank 1. In this way, in the first high temperature side heat exchange unit 31, the heat storage medium is heated by using the exhaust heat medium (combustion exhaust gas). As a result, the temperature of the combustion exhaust gas, which is the exhaust heat medium, decreases, and the water contained in the combustion exhaust gas becomes condensed water. Then, the condensed water flows into the water tank 3 through the water recovery path 2 connected so as to branch off from the combustion exhaust gas path 29.

[Cold heat storage operation]
FIG. 4 is a diagram for explaining the cold heat storage operation, and the flow of gas and each medium is highlighted with a thick line. When performing a cold heat storage operation in which a relatively low temperature heat storage medium is newly stored in the heat storage tank 1, the heat storage medium taken out from the upper port 40 of the heat storage tank 1 is taken out from the second conversion unit 38 (second low temperature) of the thermoacoustic refrigeration apparatus 30A. After cooling by the side heat exchange unit 37), the heat storage medium is flowed so as to return to the lower port 42 of the heat storage tank 1. That is, when the cold heat storage operation is performed, the combustion exhaust gas discharged from the combustion unit 27 is used as an exhaust heat medium, and the heat energy of the exhaust heat medium is consumed to heat the high temperature side of the first conversion unit 34. Specifically, when the cold heat storage operation is performed, the fluid is circulated between the first conversion unit 34 and the second conversion unit 38 through the fluid circulation path 44 to form the high temperature side of the first conversion unit 34. By supplying the exhaust heat medium to the first high temperature side heat exchange unit 31, the first high temperature side heat exchange unit 31 is made relatively hot, and the first low temperature side heat exchange constituting the low temperature side of the first conversion unit 34 By supplying the fluid circulating in the fluid circulation path 44 to the unit 33, the first low temperature side heat exchange unit 33 is made relatively low temperature, and the first high temperature side heat exchange unit 31 and the first low temperature side heat exchange unit 33 are made. Acoustic energy is generated by the temperature gradient generated by the above, and the acoustic energy is propagated from the first conversion unit 34 to the second conversion unit 38 through the loop tube 39, and constitutes the high temperature side of the second conversion unit 38. The fluid circulating in the fluid circulation path 44 is supplied to the second high temperature side heat exchange unit 35, and the second low temperature side heat exchange unit 37 constituting the low temperature side of the second conversion unit 38 is taken out from the upper port 40 of the heat storage tank 1. The heat storage medium taken out from the upper port 40 of the heat storage tank 1 is cooled by the second low temperature side heat exchange unit 37 due to the temperature gradient generated by supplying the heat storage medium and converting the acoustic energy of the working medium into heat energy. do.

During the cold heat storage operation, frost may form on the second low temperature side heat exchange unit 37, which may cause a failure. Therefore, in the present embodiment, when the cold heat storage operation is being performed, under the control of the control device C, the radiator 45 is set so that the temperature of the second low temperature side heat exchange unit 37 becomes 0 ° C. or higher. The amount of heat released per unit time from the fluid flowing through the fluid circulation path 44 is adjusted. Alternatively, when the cold heat storage operation is being performed, under the control of the control device C, the pump P3 as the flow velocity regulator is fluid so that the temperature of the second low temperature side heat exchange unit 37 becomes 0 ° C. or higher. The flow velocity of the fluid flowing through the circulation path 44 is adjusted. Alternatively, when the cold heat storage operation is being performed, the second low temperature side heat exchange unit 37 controls the second low temperature side heat exchange unit 37 so that the temperature of the second low temperature side heat exchange unit 37 becomes 0 ° C. or higher under the control of the control device C. The flow rate per unit time of the heat storage medium taken out from the upper port 40 of the heat storage tank 1 to be cooled is adjusted. It should be noted that the above-mentioned operation may be performed only for a preset period.

As described above, in the heat storage system of the present embodiment, the heat discharged from the fuel cell device 20 can be stored in the heat storage tank 1 in a hot state by the heat storage operation, and the cold heat using the thermoacoustic refrigeration device 30 can be stored. By the storage operation, it can be stored in the heat storage tank 1 in a cold state. Therefore, it is possible to provide a heat storage system capable of storing the heat discharged from the fuel cell device 20 in both hot and cold states.

<Second Embodiment>
The heat storage system of the second embodiment is different from the above-described embodiment in the mode of heat recovery from the exhaust heat medium holding the heat discharged from the fuel cell device 20. The heat storage system of the second embodiment will be described below, but the description of the same configuration as that of the above embodiment will be omitted.

FIG. 5 is a diagram showing the configuration of the heat storage system of the second embodiment. As shown in the figure, in this heat storage system, in the middle of the fluid circulation path 44, the exhaust heat medium (combustion exhaust gas) after heat exchange is performed by the first high temperature side heat exchange section 31, and the fluid flowing through the fluid circulation path 44. It is provided with a heat exchange unit 47 that exchanges heat with and from. By providing the heat exchange unit 47, the heat storage system can recover more heat from the exhaust heat medium (combustion exhaust gas) than in the first embodiment. That is, since the combustion exhaust gas can be cooled to a lower temperature, more water contained in the combustion exhaust gas can be condensed and recovered in the water tank 3.

< Reference form>
Although not within the scope of rights of the present application, the heat storage system of the reference embodiment differs from the above embodiment in the mode of heat recovery from the exhaust heat medium holding the heat discharged from the fuel cell device 20. The heat storage system of the reference embodiment will be described below, but the description of the same configuration as that of the above embodiment will be omitted.

6 and 7 are diagrams showing the configuration of the heat storage system of the reference form. Specifically, FIG. 6 is a diagram for explaining the heat storage operation, and FIG. 7 is a diagram for explaining the cold heat storage operation. As shown in the figure, in the heat storage system of the present reference embodiment, the heat storage tank 1 includes a heat storage tank 1B for heat recovery and a heat storage tank 1A for cold heat recovery. Further, the heat storage system exchanges heat between the exhaust heat medium (combustion exhaust gas) after heat exchange in the first high temperature side heat exchange unit 31 and the heat storage medium taken out from the heat recovery tank 1B for heat recovery. It is provided with a heat exchange unit 46 for heat recovery. In the heat storage system, the heat storage medium taken out from the heat recovery tank 1B does not pass through the second low temperature side heat exchange unit 37, but passes through the first high temperature side heat exchange unit 31, and then the heat storage medium for heat recovery. The heat recovery flow path 43a flowing before returning to the tank 1B and the heat storage medium taken out from the cold heat recovery heat storage tank 1A do not pass through the first high temperature side heat exchange section 31 and are on the second low temperature side. It is provided with a cold heat recovery flow path 43b that flows after passing through the heat exchange unit 37 and before returning to the cold heat recovery heat storage tank 1A.

[Heat accumulation operation]
FIG. 6 is a diagram for explaining the thermal storage operation, and the flow of gas and each medium is highlighted with a thick line. In this case, the heat storage medium taken out from the heat recovery tank 1B passes through the heat recovery flow path 43a and does not pass through the second low temperature side heat exchange section 37, but instead passes through the heat recovery section 46. After passing through, it returns to the heat storage tank 1B for heat recovery. Then, when the heat storage operation is performed, the heat storage medium taken out from the lower port 41 of the heat recovery heat storage tank 1B by the heat recovery heat exchange unit 46 is heat-exchanged by the first high temperature side heat exchange unit 31. After heating with the exhaust heat medium (combustion exhaust gas) of the above, the heat storage medium is flowed so as to return to the upper port 40 of the heat recovery tank 1B for heat recovery. As a result, heat is stored in the heat storage tank 1B for heat recovery.

[Cold heat storage operation]
FIG. 7 is a diagram for explaining the cold heat storage operation, and the flow of gas and each medium is highlighted with a thick line. In this case, the heat storage medium taken out from the cold heat recovery heat storage tank 1A passes through the cold heat recovery flow path 43b and does not pass through the first high temperature side heat exchange section 31, but the second low temperature side heat exchange section 37. After passing through, the process returns to the heat storage tank 1A for cold heat recovery. Then, when the cold heat storage operation is performed, the fluid is circulated between the first conversion unit 34 and the second conversion unit 38 through the fluid circulation path 44, and the first high temperature constituting the high temperature side of the first conversion unit 34 is formed. By supplying the exhaust heat medium to the side heat exchange unit 31, the first high temperature side heat exchange unit 31 is heated to a relatively high temperature, and the first low temperature side heat exchange unit 33 constituting the low temperature side of the first conversion unit 34. By supplying the fluid circulating in the fluid circulation path 44, the first low temperature side heat exchange section 33 is made relatively low temperature, and the first high temperature side heat exchange section 31 and the first low temperature side heat exchange section 33 generate the heat exchange section 33. Acoustic energy is generated by the temperature gradient, and the acoustic energy is propagated from the first conversion unit 34 to the second conversion unit 38 through the loop tube 39, and the second conversion unit 38 constitutes the high temperature side. The fluid circulating in the fluid circulation path 44 is supplied to the high temperature side heat exchange section 35, and the second low temperature side heat exchange section 37 constituting the low temperature side of the second conversion section 38 is supplied from the upper port 40 of the cold heat recovery heat storage tank 1A. The heat storage medium taken out from the upper port 40 of the cold heat recovery heat storage tank 1A is exchanged for heat on the second low temperature side due to the temperature gradient generated by supplying the taken out heat storage medium and converting the acoustic energy of the working medium into heat energy. It is cooled by the part 37. As a result, cold heat is stored in the heat storage tank 1A for cold heat recovery.

<Another Embodiment>
<1>
In the above embodiment, the configuration of the heat storage system has been described with specific examples, but the configuration can be changed as appropriate.
For example, as in the thermoacoustic refrigerating apparatus 30B (30) shown in FIG. 8, the loop pipe 51 has a first loop pipe 51a passing through the first conversion unit 34 and a second loop pipe 51b passing through the second conversion unit 38. It may be configured to include.
In addition, although the fluid circulation path 44 is a closed flow path in the above embodiment, the fluid circulation path 44 may be opened to the atmosphere in the middle of the flow path. For example, an expansion tank may be provided in the middle of the fluid circulation path 44, and the expansion tank may be opened on standby.

<2>
In the above embodiment, the type of the heat storage medium stored in the heat storage tank 1 and the fluid flowing through the fluid circulation path 44 is not limited to the above-mentioned specific example, and can be changed as appropriate.

<3>
In the above embodiment, the heat storage operation may be performed at the set timing during the cold heat storage operation. For example, in the heat storage system shown in FIGS. 2 and 5, the heat storage operation may be performed for a predetermined period at the set timing during the cold heat storage operation, and then the cold heat storage operation may be performed again. When such an operation is performed, a heat storage medium having a relatively high temperature is stored in the upper part of the heat storage tank 1 (near the upper port 40) by the heat storage operation. Then, when the cold heat storage operation is started again, the heat storage medium having a relatively high temperature is supplied to the second low temperature side heat exchange unit 37, and the temperature of the second low temperature side heat exchange unit 37 rises. As a result, even if frost is formed on the second low temperature side heat exchange unit 37 during the cold heat storage operation, it can be expected that the frost will melt.
Here, the timing at which the hot storage operation is performed during the cold heat storage operation can be appropriately set. For example, when a predetermined condition is satisfied such that the continuous period of the cold heat storage operation is longer than the predetermined period or the temperature of the second low temperature side heat exchange unit 37 is lower than the predetermined temperature, the heat is heated for a predetermined period. Accumulation operation can be performed.

<4>
The configurations disclosed in the above embodiment (including other embodiments, the same shall apply hereinafter) can be applied in combination with the configurations disclosed in other embodiments as long as there is no contradiction, and are disclosed in the present specification. The embodiment is an example, and the embodiment of the present invention is not limited to this, and can be appropriately modified without departing from the object of the present invention.

The present invention can be used in a heat storage system capable of storing the heat discharged from the fuel cell device in both hot and cold states.

1 Heat storage tank 1A Heat storage tank for cold heat recovery 1B Heat storage tank for hot heat recovery 20 Fuel cell device 23 Remodeling unit 24 Anode 25 Cathode 27 Burning unit 30 Thermal acoustic refrigeration device 30A Thermal acoustic refrigeration device 30B Thermal acoustic refrigeration device 31 First high temperature side Heat exchange unit 33 1st low temperature side heat exchange unit 34 1st conversion unit 35 2nd high temperature side heat exchange unit 37 2nd low temperature side heat exchange unit 38 2nd conversion unit 39 Loop tube 40 Upper port 41 Lower port 42 Lower port 43a Heat recovery channel (heat storage medium channel)
43b Cold heat recovery flow path (heat storage medium flow path)
44 Fluid circulation path 45 Heat sink 46 Heat exchange section for heat recovery 47 Heat exchange section 50 Fuel cell section 51 Loop pipe

Claims (8)

It is equipped with a fuel cell device, a thermoacoustic refrigeration device, and a heat storage tank that can store heat using a heat storage medium.
The thermoacoustic refrigeration apparatus has a loop tube formed in an annular shape and filled with an operating medium inside, and exhaust heat that is provided in the middle of the loop tube and retains heat discharged from the low temperature side and the fuel cell apparatus. A first conversion unit that generates acoustic energy by a temperature gradient between the heat energy of the medium and the high temperature side to which the heat energy is supplied, and a first conversion unit that is provided in the middle of the loop tube and propagates from the first conversion unit through the loop tube. A heat storage system having a second conversion unit that can discharge cold heat from the low temperature side to the outside by utilizing the temperature gradient generated between the low temperature side and the high temperature side by converting the generated acoustic energy into heat energy. There,
The heat storage tank can store the heat storage medium inside in a state of forming a temperature stratification in which the upper part is relatively high temperature and the lower part is relatively low temperature, and the heat storage tank is provided with an upper port provided on the upper side of the heat storage tank. The heat storage medium is configured to flow inside and outside the heat storage tank via a lower port provided on the lower side.
When performing a heat storage operation for newly storing the heat storage medium having a relatively high temperature in the heat storage tank, the heat storage medium taken out from the lower port of the heat storage tank is heated by the exhaust medium, and then the heat storage medium is stored. Flowing so that it returns to the upper port of the heat storage tank,
When performing a cold heat storage operation in which the heat storage medium having a relatively low temperature is newly stored in the heat storage tank, the heat storage medium taken out from the upper port of the heat storage tank is cooled by the second conversion unit of the thermoacoustic refrigeration apparatus. After that, the heat storage medium is flowed so as to return to the lower port of the heat storage tank .
A fluid circulation path through which a fluid can circulate between the first conversion unit and the second conversion unit is provided.
When performing the cold heat storage operation
A fluid is circulated between the first conversion unit and the second conversion unit through the fluid circulation path.
By supplying the exhaust heat medium to the first high temperature side heat exchange unit constituting the high temperature side of the first conversion unit, the first high temperature side heat exchange unit is made relatively hot, and the first conversion unit By supplying the fluid circulating in the fluid circulation path to the first low temperature side heat exchange section constituting the low temperature side, the first low temperature side heat exchange section is relatively cooled, and the first high temperature side heat exchange section is used. And the acoustic energy is generated by the temperature gradient generated by the first low temperature side heat exchange unit.
In a state where the acoustic energy is propagated from the first conversion unit to the second conversion unit through the loop tube, the fluid circulation to the second high temperature side heat exchange unit constituting the high temperature side of the second conversion unit. A fluid circulating in the path is supplied, and the heat storage medium taken out from the upper port of the heat storage tank is supplied to the second low temperature side heat exchange section constituting the low temperature side of the second conversion section to supply the working medium. A heat storage system in which the heat storage medium taken out from the upper port of the heat storage tank is cooled by the second low temperature side heat exchange unit by a temperature gradient generated by converting acoustic energy into heat energy. The fuel cell device includes a reforming unit for steam reforming raw fuel to generate fuel gas, an anode to which the fuel gas generated in the reforming unit is supplied, and a cathode to which oxygen gas is supplied. It has a fuel cell unit having a fuel cell unit, and a combustion unit that burns fuel components in the exhaust fuel gas discharged from the anode after being used in a power generation reaction in the fuel cell unit.
When the heat storage operation is performed, the combustion exhaust gas discharged from the combustion unit is used as the heat exhaust medium, and the heat energy of the heat storage medium is used to heat the heat storage medium taken out from the lower port of the heat storage tank. Consume and
When the cold heat storage operation is performed, the combustion exhaust gas discharged from the combustion unit is used as the exhaust heat medium, and the heat energy of the exhaust heat medium is consumed to heat the high temperature side of the first conversion unit.
The heat storage system according to claim 1, wherein the condensed water is recovered from the combustion exhaust gas whose temperature has been lowered due to heat energy consumption, and the condensed water is used for steam reforming of raw fuel in the reforming section. The heat storage system according to claim 1 or 2, further comprising a radiator capable of adjusting the amount of heat radiated from the fluid per unit time in the middle of the fluid circulation path. When the cold heat storage operation is being performed, the radiator dissipates heat from the fluid flowing through the fluid circulation path per unit time so that the temperature of the second low temperature side heat exchange unit becomes 0 ° C. or higher. The heat storage system according to any one of claims 1 to 3. A flow velocity controller capable of adjusting the flow velocity of the fluid flowing through the fluid circulation path is provided.
The claim that the flow velocity regulator adjusts the flow velocity of the fluid flowing through the fluid circulation path so that the temperature of the second low temperature side heat exchange section becomes 0 ° C. or higher when the cold heat storage operation is performed. The heat storage system according to any one of 1 to 4. The heat storage medium taken out from the heat storage tank does not pass through the second low temperature side heat exchange section, but flows through the first high temperature side heat exchange section until it returns to the heat storage tank. A flow path for heat recovery and
The heat storage medium taken out from the heat storage tank does not pass through the first high temperature side heat exchange section, but flows through the second low temperature side heat exchange section until it returns to the heat storage tank. The heat storage system according to any one of claims 1 to 5, further comprising a flow path for cold heat recovery. A fluid circulation path through which a fluid can circulate between the first conversion unit and the second conversion unit is provided.
When the heat storage operation is performed, the heat storage medium taken out from the lower port of the heat storage tank is heated by the exhaust medium in the first high temperature side heat exchange unit constituting the high temperature side of the first conversion unit. The heat storage system according to any one of claims 1 to 6, wherein the heat storage medium is allowed to flow so as to return to the upper port of the heat storage tank. Claimed to include a heat exchange unit in the middle of the fluid circulation path, which exchanges heat between the exhaust heat medium after heat exchange in the first high temperature side heat exchange unit and the fluid flowing through the fluid circulation path. The heat storage system according to any one of 1 to 7.

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