JP3961198B2 - Waste heat fuel cell - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a waste heat utilization fuel cell, and more specifically, efficiently utilizes heat dissipated from the fuel cell itself and various energy contained in the fuel electrode exhaust, air electrode exhaust, and the like as hot water. The present invention relates to a waste heat utilization fuel cell.
[0002]
[Prior art]
A fuel cell is a device that directly converts the chemical energy of a fuel into electrical energy through an electrochemical reaction between the fuel and an oxidant, and the theoretical conversion rate from fuel to DC power reaches over 80%. . However, in practice, the conversion efficiency is generally about 50% or less due to the influence of various resistances, that is, polarization. Energy that is not converted into electric power is released as exhaust heat. Effective use of this energy is also effective for effective use of energy and, in turn, reduction of carbon dioxide emissions.
[0003]
In particular, in order to effectively use the exhaust heat, it is necessary to recover the exhaust heat at a temperature level as close as possible to the temperature of the exhaust heat source, that is, the fuel cell. Further, since a relatively small amount of heat is usually emitted from a surrounding fuel cell, it is necessary to suppress this as much as possible and to transmit heat to a heat medium (water, air, etc.) for exhaust heat recovery without waste. . The exhaust heat of the fuel cell is usually transmitted to a heat medium such as cooling water or cooling air, and the heat medium is guided to the outside of the fuel cell and directly or indirectly utilizes heat contained in the heat medium. For example, when the heat medium is water, the battery cooling water coming out of the fuel cell is directly used as hot water, or the hot water is generated by directing it to a heat exchanger for generating hot water or a hot water storage tank containing it. Is used.
[0004]
The heat radiation from the outer surface of the fuel cell is larger than the amount of exhaust heat, particularly in the case of a small-capacity fuel cell, and the amount of heat that can be used is substantially reduced. In addition, when using indirectly, there is a problem of lowering the available temperature level in addition to heat loss due to heat radiation in the piping route to the use place where the heat exchanger is arranged. . Furthermore, a large installation space is required by providing a fuel cell body and a hot water tank.
[0005]
Although there are various types of fuel cells, FIG. 9 is a schematic diagram illustrating an example of a water-cooled polymer electrolyte fuel cell (PEFC) as an example. In FIG. 9, 1 is a polymer electrolyte membrane, 2 is a cathode electrode (positive electrode = air electrode or oxygen electrode), 3 is an anode electrode (negative electrode = fuel electrode or hydrogen electrode), and the polymer electrolyte membrane 1 is opposed to this. The positive and negative electrodes 2 and 3 are disposed in contact with each other. Reference numeral 4 denotes a cathode electrode side current collector, and 5 denotes an anode electrode side current collector, which are in contact with the positive and negative electrodes 2 and 3, respectively.
[0006]
A groove for supplying oxygen or air is provided on the electrode 2 side of the cathode electrode side current collector 4, and a fuel supply groove is provided on the electrode 3 side of the anode electrode side current collector 5. The groove of the body 4 communicates with the oxygen or air supply pipe 6, and the groove of the negative current collector 5 communicates with the fuel supply pipe 7. 8 is a cathode terminal plate provided in contact with the positive current collector 4, and 9 is an anode terminal plate provided in contact with the negative current collector 5. Power is passed through these terminal plates during operation of the battery. Is taken out.
[0007]
Reference numeral 10 denotes a left frame, and 11 a right frame, and these frames 10 and 11 cover and fix the polymer electrolyte membrane 1 to the cathode terminal plate 8 and the anode terminal plate 9. A packing 12 is provided between the frame bodies 10 and 11 so as to surround the peripheral edge from the polymer electrolyte membrane 1 to the cathode terminal plate 8 and the anode terminal plate 9. The above is a case where a single battery is used, but it can be configured by stacking two or more batteries, but is basically the same as the case of the single battery described above.
[0008]
Since PEFC needs to be maintained at a temperature of about 80 to 100 ° C. during operation, it is cooled by battery cooling water. The cooling water communicates with the grooves (closed passages) provided on the inner surfaces of the left frame body 10 and the right frame body 11 and indirectly cools from the back surfaces of the cathode terminal plate 8 and the anode terminal plate 9. Warmed and discharged. The discharged cooling water is cooled to an appropriate temperature by a heat exchanger and circulated and supplied to the fuel cell. In FIG. 9, P is the circulation pump. In general, the fuel cell has an optimum operating temperature range depending on the type of the fuel cell, and heat generated by the power generation must be removed. For this reason, it is necessary to cool with cooling water, cooling air, or the like, and it is conceivable to make effective use of heat via the cooling water, cooling air, or the like.
[0009]
FIG. 10 shows an example in which the heat of battery cooling water is used for hot water by a heat exchanger. In this case, when the heat for hot water is insufficient, the heat from the boiler is also used and hot water is supplied from the hot water storage tank. In this way, when exhaust heat utilization equipment such as heat exchangers, boilers, pumps, etc. are arranged independently of the fuel cell main body, each equipment and various pipes will be exposed to the surrounding environment. Even so, there is an energy loss due to heat dissipation according to the surface temperature and surface area. In addition, with the increase in the number of components, there is a problem that the disadvantage in terms of initial cost due to the increase in the installation area and the cost of the equipment itself offset the cost reduction due to the effective use of exhaust heat to some extent.
[0010]
By the way, in the fuel cell, it is difficult to use 100% of the gas serving as the fuel. For example, even when the fuel is high-purity hydrogen, trace impurities accumulate in the fuel electrode gas as power generation continues, and a trace purge is required. However, in this case, only a very small amount of surplus fuel is dissipated. However, when using a gas containing a gas other than hydrogen to some extent, for example, a gas containing hydrogen (reformed gas) obtained by reforming a fuel containing carbon such as city gas, LPG, or methanol, the hydrogen content in the fuel electrode In order to prevent the pressure from dropping more than necessary, it is necessary to constantly discharge excess fuel from the fuel electrode. If this surplus fuel is dissipated without using it, there will be a significant energy loss. Also in the embodiment of FIG. 10, when the fuel utilization rate has to be lowered, an energy loss accompanying fuel discharge occurs.
[0011]
FIG. 11 shows an example in which the fuel electrode exhaust is recycled to the fuel electrode inlet side by a recycle pump in order to reduce the energy loss caused by the fuel discharge. Although it is possible to reduce the amount of surplus fuel discharged by this measure, a certain amount of surplus fuel must be discharged because gas other than hydrogen accumulates in the fuel system with energy loss for recycling. Furthermore, facilities such as piping and pumps for recycling surplus fuel are also required, which is disadvantageous in terms of cost, particularly when the fuel cell (FC) is a small capacity machine.
[0012]
An example of effectively using surplus hydrogen is shown in FIG. In other words, surplus fuel is recycled to a reformer (reforming city gas or the like into reformed gas containing hydrogen), burned, and effectively used by supplying heat necessary for the reforming reaction, preventing energy loss. It is out. However, in this aspect, it can be applied only when the reformer is attached to the fuel cell body, and even if it is attached, the reformer is not an external heating type like a steam reformer, but a partial combustion modification. It cannot be applied when external heating is not required, such as in a pouch. 11 and 12, there are problems similar to those of the embodiment of FIG. 10, that is, problems such as energy loss due to heat radiation from each device and piping for use of exhaust heat, and equipment cost increase.
[0013]
As the exhaust heat of the fuel cell, in addition to the fuel electrode exhaust, the air electrode exhaust also has heat at the operating temperature level of the fuel cell, and this exhaust heat is often recovered. Specifically, a separate heat exchanger from the fuel cell is used. However, in this case as well, there are the same problems of heat dissipation loss and equipment cost increase as when exhaust heat recovery is performed from battery cooling water, cooling air, or the like. Furthermore, in the case of a fuel cell that is operated at a low temperature, such as PEFC, the heat exchanger is intended for low-temperature gas, so installation space associated with a decrease in the heat recovery temperature or an increase in the size of the heat exchanger There are also problems in terms of equipment costs.
[0014]
[Problems to be solved by the invention]
The present invention eliminates the above-mentioned various disadvantages considered in the case of using heat of fuel electrode exhaust, air electrode exhaust, surplus hydrogen in fuel electrode exhaust, or cell cooling water in a fuel cell, It is an object of the present invention to provide an exhaust heat utilization fuel cell that can be taken out as warm water (hot water) without substantially reducing the temperature level of the exhaust heat of the exhaust gas and that enhances the energy utilization efficiency of those.
[0016]
[Means for Solving the Problems]
  The present invention,(one)A fuel cell that heats feed water by exhaust heat of a fuel cell and uses it as hot water for recovering exhaust heat from the fuel cell bodyWith a recessHot water storage container or hot water distribution containerRecess inThe exhaust heat utilization fuel cell is characterized in that the hot water is generated by passing the battery cooling water of the fuel cell through a heat exchanger disposed in the water in the hot water storage container or the hot water circulation container. I will provide a.
[0017]
  The present invention,(two)A fuel cell that heats feed water by exhaust heat of a fuel cell and uses it as hot water for recovering exhaust heat from the fuel cell bodyWith a recessHot water storage container or hot water distribution containerRecess inAnd housed in(1)Combustion gas obtained by combusting the exhaust of the fuel electrode of the fuel cell with a combustor,(2)The fuel cell is cooled by air, warm air discharged after the fuel cell is cooled, and(3)Provided is an exhaust heat utilization fuel cell characterized in that at least one of exhaust gases from an air electrode is directly blown into water in a hot water storage container or a hot water circulation container.
[0019]
  The present invention,(three)A fuel cell that heats feed water by exhaust heat of a fuel cell and uses it as hot water for recovering exhaust heat from the fuel cell bodyWith a recessHot water storage container or hot water distribution containerRecess inAnd a mechanism for humidifying at least one of the fuel supplied to the fuel electrode and the air supplied to the air electrode with the hot water in the container in the hot water storage container or the hot water circulation container. An exhaust heat utilizing fuel cell is provided.
[0020]
  The present invention, (Four)A fuel cell that heats feed water by exhaust heat of a fuel cell and uses it as hot water for recovering exhaust heat from the fuel cell bodyWith a recessHot water storage container or hot water distribution containerRecess inAnd spraying the water supply to the hot water storage container or hot water distribution container into the hot water storage container or hot water distribution container,(1)Combustion gas that burns the exhaust of the fuel electrode of the fuel cell,(2)The fuel cell is cooled by air, warm air discharged after the fuel cell is cooled, and(3)Provided is an exhaust heat utilization fuel cell characterized by being in direct contact with at least one of exhaust gases from an air electrode.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
In a fuel cell, an exothermic reaction (H₂+ 1 / 2O₂= H₂O) generates heat. The present invention prevents the heat generated in the fuel cell from being dissipated as much as possible by housing the fuel cell main body in a container for storing warm water or a container for circulating warm water, and heats the water supply with the heat. This is a waste heat utilization fuel cell that is used as hot water. As the fuel, hydrogen obtained by various production methods or a gas containing hydrogen (reformed gas or the like) is used. In addition to air, oxygen-enriched air or the like is used as the oxidant, but in this specification, these are referred to as air.
[0024]
Moreover, in this specification, the container which stores warm water is designated as a warm water storage container, and the container for circulating warm water is designated as a warm water circulation container. Here, the hot water storage container means a container that discharges hot water as needed, such as a hot water storage tank, and water is supplied to the container through a conduit, heated there, and hot water is supplied through the conduit. The hot water distribution container means a container that is arranged in the middle of a conduit such as a water pipe and always uses the hot water obtained there (may be temporarily stopped). Hereinafter, the hot water storage container is described except when particularly necessary, but the same applies to the hot water circulation container.
[0025]
A warm water storage container is comprised by the double wall structure of an inner wall and an outer wall. The same applies to the bottom. A lid is sealed between the upper end of the inner wall and the upper end of the outer wall. A heat insulating material or the like is disposed on the outer surface of the outer wall, the bottom, and the lid to be insulated. Water such as tap water is supplied between the inner and outer walls. A space is provided in the inner wall, and the fuel cell main body is disposed in the space. The upper part in the inner wall is insulated by arranging a heat insulating material after arranging the fuel cell main body. In the present invention, heat from the fuel cell main body is thereby transmitted to the water supplied between the two walls through the inner wall, and the water supply is heated to warm water (hot water). The fuel to be supplied to the fuel cell, the air conduits, the fuel cell exhaust from the fuel cell, the air electrode exhaust conduits, the power extraction lead, etc. are preferably extended from the upper part of the inner wall. However, it may be arranged in any other appropriate manner.
[0026]
Although there are various types of fuel cells, each fuel cell is operated within a predetermined temperature range. For example, it is maintained in a temperature range of about 80 to 100 ° C. for PEFC and about 190 to 200 ° C. for a phosphoric acid fuel cell. For this reason, it is necessary to cool the fuel cell during operation with cooling water, cooling air, or the like, and to maintain such a temperature range. In the present invention, the battery cooling water or the like is circulated to the heat exchanger provided between the inner wall and the outer wall of the hot water storage container, so that the heat of the battery cooling water or the like is used for heating the water in the hot water storage container.
[0027]
Fuel electrode exhaust is discharged from the fuel electrode of the fuel cell. Since the anode exhaust itself has heat, the heat is used for heating water in the present invention. Further, since surplus hydrogen is contained in the fuel electrode exhaust, in the present invention, the surplus hydrogen is combusted, and the generated combustion gas is blown directly into the water between the inner wall and the outer wall of the hot water storage container, thereby generating the heat. Is used for water heating. Although air is necessary for combustion of surplus hydrogen, air from the outside may be used as the air. However, when air is used for exhausting the air electrode or cooling the fuel cell, the air can be used. In addition, a catalytic combustor can be preferably used for the combustion. As the catalyst, for example, a noble metal catalyst such as platinum or palladium is used.
[0028]
The exhaust from the air electrode of the fuel cell also holds heat. In the present invention, the exhaust from the air electrode is directly blown into the water in the hot water storage container to be used for heating the water. In some cases, the fuel cell uses air instead of the battery cooling water for cooling. In this case, the battery cooling air itself is heated. Therefore, in the present invention, the air emitted from the fuel cell is directly blown into the water in the hot water storage container to be used for heating the water. In this case, the air may be blown into the water in the hot water storage container together with the air electrode exhaust.
[0029]
It is efficient for the fuel cell to preheat the fuel supplied to the fuel cell. In the present invention, the fuel is heated with hot water in a hot water storage container and supplied to the fuel cell. As a result, the heat in the fuel cell system can be effectively used. The fuel can be heated by a heat exchange mechanism disposed in the hot water storage container, and a finned tube or other appropriate type of heat exchanger can be used as the heat exchange mechanism.
[0030]
In the case of PEFC or the like, one or both of the supplied fuel and the supplied air are usually humidified in order to prevent deterioration of the characteristics of the electrolyte membrane. In the present invention, the humidification can be performed by passing through a water-permeable humidifier made of a polymer film, porous ceramics, or the like disposed in the hot water storage container. As described above, the hot water in the hot water storage container can be used for humidifying at least one of the supply fuel and the supply air, that is, one or both of them. The humidification can be applied as a modified embodiment even when the fuel cell main body is not accommodated in the hot water storage container.
[0031]
Furthermore, in the present invention, the battery in the case where the supply water is sprayed in the hot water storage container, that is, between the inner wall and the outer wall thereof, and air is used instead of the combustion gas of the fuel electrode exhaust, the air electrode exhaust, or the battery cooling water. By making it contact with cooling air directly, the heat which these gases hold | maintain can be utilized still more effectively. In this case, the contact efficiency between the water supply and these gases can be increased by arranging a Raschig ring or the like in the hot water storage container.
[0032]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated in more detail based on an Example, of course, this invention is not limited to these Examples. 1 to 8 correspond to Embodiments 1 to 8, respectively, and the same reference numerals are used for common portions in the drawings.
[0033]
Example 1
FIG. 1 is a diagram illustrating a first embodiment. The hot water storage container has a double wall structure of an inner wall K and an outer wall L. The same applies to the bottom. A space S is provided in the inner wall K, and the fuel cell main body is disposed in the space S. In FIG. 1, the fuel cell main body is shown in a relatively reduced size. Water is supplied between the inner wall K and the outer wall L, heat from the fuel cell body is transmitted to the water through the inner wall K, and the water is heated to warm water. In order to make the heat from the inner wall K available as much as possible, it is desirable that the water surface in the double wall structure be at a high position. These points are the same as in Examples 2 to 7. In the case of Example 8 which will be described later, since the direct contact type heat exchange mechanism with the air electrode exhaust or the like is provided, the water surface is lowered accordingly.
[0034]
The inner wall K can have an appropriate shape such as a quadrilateral or other polygonal shape, a circular shape, or a deformed shape thereof. Since it is necessary to transmit heat from the fuel cell main body more effectively through the inner wall K, the cross-sectional shape thereof is the same as the shape of the outer peripheral side of the fuel cell main body or a shape that matches the outer peripheral side shape as much as possible. It is preferable to do this. Although the outer wall L is also configured in a shape corresponding to this, in the case where a heat exchange mechanism or a humidifying mechanism is disposed between the inner wall K and the outer wall L as in Example 6 (see FIG. 6) described later, the location is The necessary width may be given to this part.
[0035]
A lid is provided between the upper end of the inner wall K and the upper end of the outer wall L and sealed as necessary. A heat insulating material or the like is arranged on the outer wall L, the bottom, and the outer surface of the lid for heat insulation. The upper part in the inner wall K is thermally insulated by disposing a heat insulating material or the like after the fuel cell main body is disposed in the space S. In addition, you may arrange | position the same lid | cover including the upper end of the inner wall K, the upper end of the outer wall L, and the upper end in the inner wall K. FIG. These points are the same in the following embodiments.
[0036]
In addition to housing the fuel cell main body in the inner wall K as described above, the battery cooling water may be circulated through a heat exchanger disposed in the water between the inner wall K and the outer wall L. In FIG. 1, P is a pump for the circulation. Thereby, in addition to the heat transmitted from the fuel cell main body through the inner wall K, the heat of the battery cooling water is used for heating the water. With these configurations, heat from the fuel cell can be effectively used for heating water, and heat radiation to the surrounding environment can be further effectively suppressed.
[0037]
Example 2
FIG. 2 is a diagram schematically showing an example in which the double wall structure of the inner wall K and the outer wall L is a jacket. In this example, the jacket surrounds the fuel cell body. As a result, heat generated during operation of the fuel cell is given to the water flowing in the jacket through the inner wall K. Although this type of container is suitable as a hot water distribution container, it can also be applied as a hot water storage container by increasing the distance between the inner wall K and the outer wall L. As shown in FIG. 2, the fuel cell body has a rectangular cross section on the outer peripheral side, and the inner wall K of the jacket housing the fuel cell main body is configured to have a slightly rounded shape on the four sides of the quadrangular cross section. ing.
[0038]
Although the bottom part may be constituted by a single wall, it may be constituted in a jacket shape. In this case, a heat exchanger may be disposed between the double walls of the bottom jacket so that the battery cooling water is circulated. The upper part of the jacket is covered, and the cover is provided with fuel to the fuel cell body, air conduits, fuel electrode exhaust from the fuel cell body, air electrode exhaust conduits, power leads, etc. The In addition, you may arrange | position these conduits etc. in an appropriate manner, such as arrange | positioning between the upper end part of a double wall structure, and a lid | cover.
As described above, as in Examples 1 and 2, the points such as the container having a double wall structure of the inner wall K and the outer wall L, and the double wall structure having a jacket shape are described in Examples 3 to 7 described below. The same applies to.
[0039]
Example 3
FIG. 3 is a diagram showing a third embodiment. Exhaust gas from the anode of the fuel cell contains heat in addition to unused hydrogen in the fuel cell. For this reason, in this example, the fuel electrode exhaust is combusted by a combustor (fuel electrode exhaust combustor), and the generated combustion gas is directly blown into the feed water in the hot water storage container and used for heating the feed water. The gas blowing is performed by arranging a porous tube or the like in the water in the container. As the combustor, a combustor in which a catalyst such as a noble metal catalyst is filled, that is, a catalytic combustor is used.
[0040]
Although air is required for combustion of the anode exhaust, the illustration of the air conduit to the combustor is omitted in FIG. The air may be air from the outside, but when air is used for exhausting the air electrode or for cooling the fuel cell, the air (air that is cooled and discharged by heating the fuel cell) is used. Is preferred. As a result, the exhaust heat can be used by combining with the combustion gas, so that the apparatus can be simplified, and it is not necessary to recover exhaust heat from each of the fuel electrode exhaust, air electrode exhaust, and battery cooling air. There is also an advantage that only exhaust heat recovery is required. The combustor is preferably provided with a backflow prevention mechanism such as a backflow prevention valve and a shutoff valve. Thereby, it is possible to prevent the warm water in the warm water storage container from flowing back into the fuel cell main body when the operation of the fuel cell is stopped.
[0041]
Example 4
FIG. 4 is a diagram showing a fourth embodiment. As in the case of the above embodiment, the fuel cell main body is arranged in the space S formed by the inner wall K. In this example, the fuel cell is cooled by air, and the hot air discharged from the fuel cell is directly blown into the water in the hot water storage container and used for heating the water. Further, the exhaust from the air electrode is directly blown into the hot water storage container, that is, the water between the inner wall K and the outer wall L, and used for heating the water. In this case, the battery cooling air and the air electrode exhaust may be combined and directly blown into the water in the hot water storage container. FIG. 4 shows this case. In addition, it is preferable to provide a backflow prevention mechanism such as a backflow prevention valve and a shutoff valve in the blowing conduit. Thereby, it is possible to prevent the warm water in the warm water storage container from flowing back into the fuel cell main body when the operation of the fuel cell is stopped.
[0042]
Example 5
FIG. 5 shows an example in which Embodiments 3 and 4 are used in combination. As in the case of the above embodiment, the fuel cell main body is disposed in the space S formed by the inner wall K. In this example, the exhaust gas from the fuel electrode is combusted by a combustor, and the generated combustion gas is directly blown into the hot water storage container, that is, the water between the inner wall K and the outer wall L to be used for heating the water. The air is cooled by air, and the warm air discharged from it is blown directly into the water in the hot water storage container to be used for heating the water. Further, the exhaust from the air electrode is directly blown into the water in the hot water storage container and used for heating the water. In this case, the battery cooling air and the air electrode exhaust may be combined and directly blown into the water in the hot water storage container. FIG. 5 shows this case.
[0043]
Example 6
FIG. 6 is a diagram showing a sixth embodiment. As in the case of the above embodiment, the fuel cell main body is disposed in the space S formed by the inner wall K. In this example, a heat exchange mechanism is provided for heating or cooling the fuel supplied to the fuel cell with the hot water in the hot water storage container. When the fuel is at a low temperature, for example, ambient temperature, it is heated with hot water, and when the fuel is a high-temperature reformed gas, it is cooled with hot water. In addition, a mechanism for humidifying the fuel supplied to the fuel cell is provided in the hot water between the inner wall K and the outer wall L. One of these mechanisms may be installed alone, or both may be juxtaposed. FIG. 6 shows a case where they are juxtaposed. The fuel is heated or cooled by a heat exchange mechanism, and then humidified by a humidification mechanism, and then supplied to the fuel cell. The fuel supplied to the fuel cell is preferably maintained at a temperature within a certain range, but in this example, the hot water in the hot water storage container can be used to adjust the temperature of the fuel. It can be used more effectively.
[0044]
In this example, a heat exchange mechanism is provided for heating the air supplied to the fuel cell with hot water in the hot water storage container. A mechanism for humidifying the air supplied to the fuel cell is provided in the hot water between the inner wall K and the outer wall L. One of these mechanisms may be installed alone, or both may be juxtaposed. FIG. 6 shows a case where they are juxtaposed. The air is heated by a heat exchange mechanism, then humidified by a humidification mechanism, and then supplied to the fuel cell. The air supplied to the fuel cell is preferably maintained at a temperature within a certain range, but in this example, the hot water in the hot water storage container can be used to adjust the temperature of the air. It can be used more effectively.
[0045]
Conventionally, humidification of fuel and air supplied to a fuel cell has been accomplished by a system in which the supply gas is blown into water controlled at a predetermined temperature by a heater or the like, and a mechanism in which a humidification mechanism is provided inside the cell stack via a membrane or the like. Has been. The former requires a large amount of energy for humidification, requires a space for the humidification container, and has a cost problem. Regarding the latter, since it is humidified using the exhaust heat of the fuel cell, there is little energy loss, but the humidification mechanism (cooling water used for humidification and the supply gas are brought into contact with each other through the humidification membrane for humidification. Etc.), the structure of the cell stack becomes complicated and the cost increases.
According to the present invention, it is not necessary to install a humidifier independently as in this example, so that the space for the humidification can be saved and the equipment cost can be reduced. Moreover, since it heats using the exhaust heat of a fuel cell, the energy regarding humidification can be decreased.
[0046]
Example 7
FIG. 7 is a diagram showing a seventh embodiment. As in the case of the above embodiment, the fuel cell main body is disposed in the space S formed by the inner wall K. In this example, a hot water storage container, that is, a space on the water surface between the inner wall K and the outer wall L is provided with a direct contact heat exchange mechanism, and water is sprayed into the hot water storage container and blown into the water in the hot water storage container. This is an example of direct gas-liquid contact with combustion gas or the like. Water sprayed between the inner wall K and the outer wall L, and (1) combustion gas obtained by burning the fuel electrode exhaust of the fuel cell, (2) the fuel cell is cooled by air, and the temperature discharged after cooling the fuel cell Direct contact is made with at least one of air and (3) fuel cell cathode exhaust, ie, one or more of these.
[0047]
That is, at least one of the combustion gas (1), the warm air (2), and the exhaust gas from the air electrode (3) is blown into the water in the hot water storage container, and then directly in contact with the sprayed water supply. Let A part or all of (1) to (3) may be brought into direct contact with the sprayed water supply without blowing into the water in the hot water storage container. The water supply is heated by heat from the fuel cell main body transmitted from the wall surface of the inner wall K, and is also heated by heat exchange by contact with those gases.
[0048]
As the direct contact type heat exchange mechanism, a Raschig ring or other member for improving gas-liquid contact is preferably arranged, and water is sprayed from above. For this reason, the water surface in a warm water storage container is set lower than the water surface of Example 1, Examples 3-6 (FIG. 1, FIG. 3-6). If the water surface is set lower than the position of the combustor of the fuel electrode exhaust, an advantage that the backflow prevention mechanism following the combustor can be omitted can be obtained.
[0049]
Furthermore, although the electric heater is arrange | positioned in the water in a warm water storage container in FIG. 7, this is for operating an electric heater according to the demand amount of warm water. The electric heater is an auxiliary heating device when the demand for hot water is large, but it can also be installed in other embodiments. Conventionally, a reheating boiler or the like has been installed outside the hot water storage container as shown in FIGS. 10 to 12. However, in the present invention, an electric heater is disposed in the water in the hot water storage container. Heat from the heater can be used for heating without waste. A gas burner, a catalytic combustor, or the like may be arranged instead of the electric heater.
[0050]
Example 8
FIG. 8 shows the eighth embodiment. This example is a modification of the sixth embodiment and is an example in which a fuel cell main body is not housed in the hot water storage container, and a fuel and air humidification mechanism is provided in the hot water storage container. The fuel cell main body is placed outside the hot water storage container, and a humidification mechanism for fuel and air supplied to the fuel cell is provided in the hot water storage container. Although FIG. 8 shows a case where a humidification mechanism is provided for both fuel and air, it may be provided for only one of them. As shown in FIG. 8, the battery cooling water may be circulated through a heat exchanger for exhaust heat recovery disposed in the hot water storage container and used for heating the feed water. Further, a mechanism for heating at least one of fuel and air may be used in the hot water storage container as in the sixth embodiment (see FIG. 6).
[0051]
【The invention's effect】
  According to the present invention, a fuel cell main body is provided for recovering exhaust heat.With a recessHot water storage container or hot water distribution containerRecess inSince the various energy of the fuel cell can be used in the hot water storage container or the hot water circulation container, the utilization efficiency of the various energy of the fuel cell can be remarkably improved. In addition, according to the present invention, various excellent effects can be obtained, for example, the hot water in the hot water storage container or the hot water circulation container can be used for heating or humidifying the fuel or air supplied to the fuel cell.
[Brief description of the drawings]
FIG. 1 shows a first embodiment of the present invention.
FIG. 2 is a diagram showing a second embodiment of the present invention (a diagram schematically showing an example in which a container is configured in a jacket-like structure).
FIG. 3 shows a third embodiment of the present invention.
FIG. 4 is a diagram showing a fourth embodiment of the present invention.
FIG. 5 is a diagram showing a fifth embodiment of the present invention.
FIG. 6 is a diagram showing Example 6 of the present invention.
7 shows a seventh embodiment of the present invention. FIG.
FIG. 8 is a diagram showing an eighth embodiment of the present invention.
FIG. 9 is a diagram schematically showing a PEFC as an example of a fuel cell.
FIG. 10 is a diagram showing an example in which the heat of battery cooling water is used for hot water by an indirect heat exchanger (conventional example).
FIG. 11 is a diagram showing an example in which surplus hydrogen of PEFC is recycled to PEFC and used (conventional example).
FIG. 12 is a diagram showing an example in which the fuel cell exhaust electrode is recycled to a reformer that generates hydrogen from city gas or the like (conventional example).
[Explanation of symbols]
1 Polymer electrolyte membrane
2 Cathode electrode (positive electrode = air electrode)
3 Anode electrode (negative electrode = fuel electrode)
4 Current collector on the cathode electrode side
5 Current collector on the anode electrode side
6 Oxygen or air supply pipe
7 Fuel (usually hydrogen) supply pipe
8 Cathode terminal board
9 Anode terminal plate
10 Left frame
11 Right frame
12 Packing
K inner wall
L outer wall
S space

Claims (7)

A fuel cell comprising as utilized as hot water to heat the feed water by exhaust heat of the fuel cell, received in the recess of the hot water reservoir or hot-water flow container having a recess for collecting the waste heat of the fuel cell body In addition, the exhaust-heat-use fuel cell is characterized in that hot water is generated by passing the battery cooling water of the fuel cell through a heat exchanger disposed in the water in the hot water storage container or the hot water circulation container. A fuel cell comprising as utilized as hot water to heat the feed water by exhaust heat of the fuel cell, received in the recess of the hot water reservoir or hot-water flow container having a recess for collecting the waste heat of the fuel cell body (1) Combustion gas obtained by burning exhaust gas from the fuel electrode of the fuel cell with a combustor, (2) Warm air discharged after the fuel cell is cooled by air and cooled, and (3) Air electrode An exhaust heat utilization fuel cell characterized in that at least one of the exhaust gas from is directly blown into water in a hot water storage container or a hot water circulation container. A fuel cell comprising as utilized as hot water to heat the feed water by exhaust heat of the fuel cell, received in the recess of the hot water reservoir or hot-water flow container having a recess for collecting the waste heat of the fuel cell body And a mechanism for humidifying at least one of the fuel supplied to the fuel electrode and the air supplied to the air electrode with the hot water in the container in the hot water storage container or the hot water circulation container. Waste heat utilization fuel cell. A fuel cell comprising as utilized as hot water to heat the feed water by exhaust heat of the fuel cell, received in the recess of the hot water reservoir or hot-water flow container having a recess for collecting the waste heat of the fuel cell body And (1) a combustion gas in which the water supply to the hot water storage container or the hot water distribution container is sprayed into the hot water storage container or the hot water distribution container, and (2) the fuel cell A waste heat utilization fuel cell, wherein the fuel cell is directly contacted with at least one of hot air cooled by air and discharged after cooling the fuel cell, and (3) exhaust from the air electrode. The exhaust heat-use fuel cell according to any one of claims 1 to 4 , wherein the fuel supplied to the fuel electrode of the exhaust heat-use fuel cell is hydrogen or a gas containing hydrogen. In the exhaust heat utilization fuel cells, in water of the hot water reservoir or hot-water flow in the container, place the electric heater motor as an auxiliary heating device for heating the hot water of the hot water reservoir or hot-water flow in the vessel in accordance with the demand of hot water The exhaust-heat-utilizing fuel cell according to any one of claims 1 to 5 , wherein the fuel cell uses exhaust heat. The exhaust heat-use fuel cell according to any one of claims 1 to 6 , wherein the fuel cell of the exhaust heat-use fuel cell is a solid polymer fuel cell.

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