JP2002134143A - Fuel cell cogeneration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell cogeneration system, capable of stably supplying hot water at a high temperature in a short time and readily coping with fluctuation in the thermal output of the fuel cell. SOLUTION: This fuel cell cogeneration system is equipped with a fuel gas generation part 1 for generating hydrogen rich fuel gas by steam reforming, a fuel cell 2 for generation electricity with the use of the fuel gas and oxidizer gas, a fuel gas humidifier 3 and an oxidizer gas humidifier 4 for humidifying the fuel gas and the oxidizer gas, an inverter 5 for inverting direct current electricity to alternating current electricity, a cooling water circulating pump 6, a cooling water circulating passage 7 and a passage interchanging valve 9 for circulating the cooling water, a heat exchanger 21 for cooling the cooling water by heat exchange with stored hot water, a stored hot water circulating passage 22 for circulating the stored hot water, a storage hot water tank 8 for storing the stored hot water, and a radiator 11 for cooling the cooling water by heat radiation. The stored hot water is returned to the storage hot water tank 8 through a stored hot water circulating passage exhaust port 23 provided in the middle part of the storage hot water tank 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell cogeneration system for generating electric power and heat.

[0002]

2. Description of the Related Art A fuel cell generates power by reacting a fuel gas such as hydrogen with an oxidizing gas such as oxygen. In this reaction, heat is generated at the same time as electric power. The fuel cell cogeneration system supplies this power and heat to an external load.

FIG. 4 shows a conventional fuel cell cogeneration system.

[0004] The fuel gas generator 1 heats a raw material such as natural gas supplied from the outside in a steam atmosphere to generate a hydrogen-rich fuel gas.

The fuel cell 2 is supplied with a fuel gas and an oxidizing gas such as air humidified by a fuel gas humidifier 3 and an oxidizing gas humidifier 4, respectively.

[0006] The DC current generated in the fuel cell 2 is converted into an AC current by an inverter 5 and then supplied to an external power load in a system link with a commercial power supply.

On the other hand, the heat generated in the fuel cell 2 is supplied to an external heat load such as hot water supply or heating as follows.

[0008] The cooling water circulation pump 6 circulates cooling water to the fuel cell 2 through a cooling water circulation path 7 in order to recover heat generated in the fuel cell 2.

City water is stored in the hot water storage tank 8.
During operation, the flow path switching valve 9 normally has an A-
The cooling water that has been connected between B and passed through the fuel cell 2 radiates heat in a heat exchanger 10 arranged at the bottom of the hot water storage tank 8. Thereby, the water inside the hot water storage tank 8 is heated. The water thus obtained is used for external heat loads such as hot water supply and heating.

Hot water cooled by supplying heat to the external heating load returns to the lower part of the hot water storage tank 8.

On the other hand, the cooling water whose temperature has been reduced by the heat radiation by the heat exchanger 10 returns to the fuel cell 2 again through the cooling water circulation path 7 by the cooling water circulation pump 6.

When the temperature of the hot water in the hot water storage tank 8 rises sufficiently,
The connection between A and C of the flow path switching valve 9 is connected, and the heat of the cooling water passing through the fuel cell 2 is discharged outside the system by the radiator 11.

[0013]

In the above-described conventional fuel cell cogeneration system, since the bottom layer of hot water is entirely heated by the heat exchanger 10 on the bottom side of the hot water storage tank 8, it is necessary to supply hot water. Low-temperature hot and cold water is generated for hot and cold water, and convection is formed in the entire hot and cold water inside the hot-water storage tank 8. As a result, the temperature difference between the hot and cold water in the hot water storage tank 8 is corrected, but it takes a long time from the start of operation to supply hot water and hot water.

That is, it takes a long time from the start of operation to supply high-temperature water to an external load.
Challenges).

Further, since a steady convection is formed inside the hot water storage tank 8, when the heat output of the fuel cell 2 fluctuates, the temperature of the hot water heated by the heat exchanger 10 becomes uneven.
Therefore, it is difficult to stably supply hot water in response to fluctuations in the heat output of the fuel cell 2.

Further, the temperature of the stored hot water cooled by the external heating load varies as the return water depending on the initial operation of the heating load and the steady operation. For this reason, temperature fluctuations and new convection are generated in the tank, and it is difficult to stably generate and supply hot and cold water.

That is, there is a problem (second problem) that it is difficult to stably supply hot and cold water to an external load.

An object of the present invention is to provide a fuel cell cogeneration system capable of supplying high-temperature hot water to an external load in a short time from the start of operation in consideration of the first problem. .

Another object of the present invention is to provide a fuel cell cogeneration system capable of stably supplying hot water to an external load in consideration of the second problem.

[0020]

According to a first aspect of the present invention, there is provided a fuel cell for generating electric power and heat using a fuel gas and an oxidizing gas. And a hot water storage tank for storing heat generated by the fuel cell as hot water, the hot water storage tank having a hot water supply port for supplying hot water to an external hot water supply load and / or an external heating load at an upper portion thereof, and The fuel cell cogeneration system is characterized in that the tank stores the hot water so that hot water located above is hotter than hot water located below.

The second invention (corresponding to claim 2)
A heat transport medium circulation path for circulating a heat transport medium for recovering the generated heat, a heat exchanger for transferring the heat recovered by the heat transport medium to the hot and cold water in the hot water tank, and A hot-water storage circuit that circulates hot water through the heat exchanger, wherein the hot-water storage tank is provided with a first storage-water circulation path for supplying hot water of the hot-water storage tank to the hot-water storage circuit, and A hot water circulation path second supply port for supplying the returned hot water to the hot water storage tank, and the hot water circulation path second supply port is provided above the hot water circulation path first supply port; And a fuel cell cogeneration system according to the first aspect of the present invention, which is provided below the hot water supply port.

Further, the third invention (corresponding to claim 3)
The hot water storage tank has a hot water supply port for supplying hot water to the hot water storage tank, and the hot water supply port is provided below the hot water circulation path second supply port. A fuel cell cogeneration system according to a second aspect of the present invention.

Further, a fourth aspect of the present invention (corresponding to claim 4)
The hot water tank supplies hot water to the external heating load, and the hot water tank has a return hot water supply port for returning hot water discharged from the external heating load to the hot water tank. Having at a predetermined height position, the predetermined height position is the temperature of the hot water stored in the hot water tank at the predetermined height position and the temperature of the hot water supplied from the return hot water supply port. The fuel cell cogeneration system according to any one of the first to third inventions, wherein the height positions are substantially the same.

The fifth invention (corresponding to claim 5)
A pump for circulating water in the hot water circulation circuit,
A temperature detector for detecting a temperature of water passing through the heat exchanger in the hot water circulation path downstream of the heat exchanger; and a hot water circulation path based on the detected temperature by increasing or decreasing the capacity of the pump. The fuel cell cogeneration system according to any one of claims 1 to 4, further comprising a pump capacity control means for adjusting a water flow rate.

The sixth invention (corresponding to claim 6)
The fifth aspect of the present invention is the fuel cell cogeneration system according to the fifth aspect, wherein the pump capacity control means adjusts the water flow rate such that the detected temperature becomes constant.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) First, Embodiment 1 will be described with reference to FIG.

FIG. 1 is a configuration diagram showing a fuel cell cogeneration system according to Embodiment 1 of the present invention.

In the fuel cell cogeneration system according to the present embodiment, the raw material supplied from the outside
In the fuel gas generator 1, the fuel gas is reformed in a steam atmosphere to generate a hydrogen-rich fuel gas.

The fuel cell 2 which generates power using the fuel gas and the oxidizing gas is supplied with the fuel gas and the oxidizing gas such as air humidified by the fuel gas humidifier 3 and the oxidizing gas humidifier 4, respectively. You.

The fuel cell 2 generates electric power and heat using a fuel gas containing hydrogen and an oxidizing gas such as air.

The DC current obtained by the fuel cell 2 is
After being converted into an alternating current in the inverter 5, it is supplied to an external power load in system interconnection with a commercial power supply.

On the other hand, the heat generated together with the electric power is stored as hot water and then supplied to the hot water supply load as described below.

That is, for example, when the fuel cell 2 is of a solid polymer type, the operating fuel cell 2 is maintained at about 80 ° C. by circulating cooling water through a cooling water circulation path 7 provided therein. . The cooling water circulation pump 6 circulates the cooling water through the cooling water circulation path 7.

The cooling water that has passed through the fuel cell 2 is usually about 70
℃ or more. At the time of heat supply such as hot water supply, the flow path switching valve 9 is connected between A and B, and the cooling water that has passed through the fuel cell 2 is supplied to the heat exchanger 21. Heat exchanger 21
The cooling water radiated through the cooling water is supplied to the fuel cell 2 again by the cooling water circulation pump 6.

On the other hand, the low temperature side of the heat exchanger 21 is connected to the hot water storage tank 8 filled with city water. Hot water storage tank 8
Hot water near the bottom is supplied to the heat exchanger 21 through the hot water circulation circuit 22 from the suction port of the hot water circulation circuit 22. Hot water that has passed through the heat exchanger 21 and has become hot is stored in the hot water storage tank 8.
The hot water enters the hot water storage tank 8 from the hot water circulation path discharge port 23 provided in the middle.

The high-temperature hot water stored in the hot-water storage tank 8 is separated from the low-temperature hot water stored in the hot-water storage tank 8 by a temperature difference between the low-temperature hot water and the low-temperature hot water. It moves upward and is stored from above the hot water storage tank 8.

City water is supplied to the hot water storage tank 8 from a supply port provided on the bottom side thereof, and hot water is supplied to an external hot water supply load such as a water heater or heating from a hot water supply port provided on the top side.

In the present embodiment, the hot water circulation path 22
Has a configuration in which hot water flows by natural convection, but a pump (not shown) for supplying hot water to the heat exchanger 21.
Is also effective in the hot water circulation path 22.

When the high-temperature hot water is sufficiently stored in the hot-water storage tank 8, the cooling water passing through the fuel cell 2 is circulated to the radiator 11 by operating the flow path switching valve 9, and the cooling water is cooled. Of heat from the system.

According to the present embodiment, for example, the operating temperature of a polymer electrolyte fuel cell is generally about 80 ° C.,
The temperature of the cooling water is 70 ° C. or more. Therefore, the temperature of the water passing through the heat exchanger 21 and returning to the hot water storage tank 8 becomes a high temperature of 60 ° C. or more. The temperature of the hot water stored in the hot water storage tank 8 filled with city water is about 20 ° C. The high-temperature hot water flowing into the hot-water storage tank 8 from the hot-water storage-circulation passage discharge port 23 provided in the middle of the hot-water storage tank 8 has a density difference caused by a temperature difference between the hot-water storage water inside the hot-water storage tank 8 and the hot water storage tank
The hot water is stored from above the hot water storage tank 8 according to the temperature distribution inside the hot water storage tank 8. Further, even when the temperature of the hot water stored in the hot water storage tank 8 fluctuates,
The inflowing hot water is stored at an appropriate hot water temperature range according to the temperature distribution inside the hot water tank 8 due to a density difference caused by a temperature difference with the hot water inside the hot water storage tank 8.

Thus, even when the fuel cell cogeneration system according to the present embodiment is operated at a partial load operation, when the low-temperature hot water which may occur when the calorific value is small flows in, the low-temperature hot water storage Due to the density difference caused by the temperature difference between the hot water and the hot water inside the hot water storage tank 8, the hot water is stored in the same temperature range inside the hot water storage tank 8, and the high temperature hot water above the hot water storage tank 8 is stirred. There is no. Therefore, the high-temperature hot water stored above the hot water storage tank 8 is not used for hot water supply.
Hot water can be stored without stirring at high temperature.

Thus, for example, when the city water temperature is 20 ° C., the upper part of the hot water storage tank 8 is at 60 ° C. and the lower part thereof is at 20 ° C. Under such conditions, the temperature gradient of the water inside the hot water storage tank 8 is maintained because the density of the high-temperature hot water in the upper portion is lower than the density of the low-temperature hot water in the lower portion.

Therefore, while the fuel cell 2 is operating, the water inside the hot water storage tank 8 forms a layer structure of the high-temperature hot water heated via the heat exchanger 21 and the low-temperature hot water before heating. Therefore, when no hot water is supplied, the high-temperature layer located above gradually increases.

Therefore, hot hot water can be stored above the hot water storage tank 8 in a short time. Further, at the time of hot water supply, water is supplied from the upper high temperature layer to the hot water supply load, so that high-temperature hot water can be constantly supplied.

(Embodiment 2) FIG. 2 is a configuration diagram showing a fuel cell cogeneration system according to Embodiment 2 of the present invention.

In the fuel cell cogeneration system according to the present embodiment, the raw material supplied from the outside
In the fuel gas generator 1, the fuel gas is reformed in a steam atmosphere to generate a hydrogen-rich fuel gas.

The fuel cell 2 which generates power using the fuel gas and the oxidizing gas is supplied with the fuel gas and the oxidizing gas such as air humidified by the fuel gas humidifier 3 and the oxidizing gas humidifier 4, respectively. You.

The fuel cell 2 generates electric power and heat using a fuel gas containing hydrogen and an oxidizing gas such as air. The DC current obtained by the fuel cell 2 is converted into an AC current by the inverter 5 and then supplied to an external power load in system interconnection with a commercial power supply.

On the other hand, the heat generated together with the electric power is stored as hot water and then supplied to the hot water supply load as described below.

For example, when the fuel cell 2 is of a solid polymer type, the operating fuel cell 2 is maintained at about 80 ° C. by circulating cooling water through a cooling water circulation path 7 provided therein.

The cooling water circulation pump 6 circulates cooling water through the cooling water circulation path 7. The cooling water that has passed through the fuel cell 2 usually reaches about 70 ° C. or higher. When supplying heat such as hot water,
The flow path switching valve 9 is connected between AB and the fuel cell 2.
Is supplied to the heat exchanger 21. The cooling water radiated through the heat exchanger 21 is supplied to the fuel cell 2 again by the cooling water circulation pump 6.

On the other hand, the low temperature side of the heat exchanger 21 is connected to the hot water storage tank 8 filled with city water. Hot water storage tank 8
The water near the inner bottom surface is sucked by the hot water circulation pump 24, and the hot water circulation
To the heat exchanger 21. The hot water stored in the hot water and having passed through the heat exchanger 21 enters the hot water storage tank 8 through a hot water circulation path discharge port 23 provided in the middle of the hot water storage tank 8.

The high-temperature hot water stored in the hot-water storage tank 8 has a density difference caused by a temperature difference between the low-temperature hot water stored in the hot-water storage tank 8 and the low-temperature hot water. It moves upward and is stored from above the hot water storage tank 8.

City water is supplied to the hot water storage tank 8 from a supply port provided on the bottom side thereof, and hot water is supplied to an external hot water supply load such as a water heater or heating from a hot water supply port provided on the top side. The thermistor 2 disposed downstream of the heat exchanger 21
5 detects the temperature of water heated by passing through the heat exchanger 21. The control unit 26 controls the hot water circulation pump 24 so that the water temperature detected by the thermistor 25 becomes constant.

When the hot water is sufficiently stored in the hot water storage tank 8, the controller 26 operates the flow path switching valve 9 to circulate the cooling water passing through the fuel cell 2 to the radiator 11. And the heat of the cooling water is discharged out of the system.

According to this embodiment, for example, the operating temperature of the polymer electrolyte fuel cell is generally about 80 ° C.
The temperature of the cooling water is 70 ° C. or more. The temperature of the hot water stored in the hot water storage tank 8 filled with city water is about 20 ° C. Therefore, when the calorific value from the fuel cell is sufficient, the heat exchanger 2
The temperature of water passing through 1 and returning to the hot water storage tank 8 can be increased to 60 ° C. or higher by control. That is, when the heat generated in the fuel cell 2 fluctuates, the flow rate of the stored hot water is adjusted by control, and the stored hot water at the target predetermined temperature (t1) is returned. The high-temperature hot water flowing into the hot water storage tank 8 from the hot water storage circuit discharge port 23 provided in the middle of the hot water storage tank 8 is located above the hot water storage tank 8 due to a density difference caused by a temperature difference with the hot water stored in the hot water storage tank 8. And the hot water is stored from above the hot water storage tank 8.

Further, when the calorific value from the fuel cell due to the partial load operation of the fuel cell cogeneration system or the like is small, fluctuations in the calorific value during the transition period and uncontrollability due to the lower limit operation of the pump are factors. Even when the incoming hot water changes in temperature or becomes colder than a predetermined temperature, the incoming hot water is subjected to a temperature distribution inside the hot water tank 8 due to a density difference caused by a temperature difference between the hot water and the hot water inside the hot water tank 8. The hot water is stored at an appropriate temperature in the hot water temperature range. That is, the hot water stored above the hot water storage tank 8 is not stirred.

Thus, for example, when the city water temperature is 20 ° C., the upper part of the hot water storage tank 8 is at 60 ° C. and the lower part is at 20 ° C. Under such conditions, the temperature gradient of the water inside the hot water storage tank 8 is maintained because the density of the high-temperature hot water in the upper portion is lower than the density of the low-temperature hot water in the lower portion.

Therefore, while the fuel cell 2 is in operation, the water in the hot water storage tank 8 forms a layered structure of high-temperature hot water heated via the heat exchanger 21 and low-temperature hot water before heating. Is done. Therefore, when there is no hot water supply, the high temperature layer located above gradually increases.

Therefore, even when the heat output of the fuel cell 1 fluctuates, hot water of high temperature and constant temperature can be stored above the hot water storage tank 8 in a short time. Further, at the time of hot water supply, water is supplied to the hot water supply load from the high temperature layer above, so that hot water can be constantly supplied.

(Embodiment 3) FIG. 3 is a configuration diagram showing a fuel cell cogeneration system according to Embodiment 3 of the present invention.

In the fuel cell cogeneration system according to the present embodiment, the raw material supplied from the outside
In the fuel gas generator 1, the fuel gas is reformed in a steam atmosphere to generate a hydrogen-rich fuel gas. An oxidizing gas such as a fuel gas and air humidified by a fuel gas humidifier 3 and an oxidizing gas humidifier 4 are supplied to a fuel cell 2 that generates power using the fuel gas and the oxidizing gas.

The fuel cell 2 generates electric power and heat using a fuel gas containing hydrogen and an oxidizing gas such as air. The DC current obtained by the fuel cell 2 is converted into an AC current by the inverter 5 and then supplied to an external power load in system interconnection with a commercial power supply.

On the other hand, the heat generated together with the electric power is stored as hot water as described below, and then supplied to an external heat load such as hot water supply or heating.

For example, when the fuel cell 2 is of a solid polymer type, the operating fuel cell 2 is maintained at about 80 ° C. by circulating cooling water through a cooling water circulation path 7 provided therein. The cooling water circulation pump 6 circulates the cooling water through the cooling water circulation path 7. The cooling water that has passed through the fuel cell 2 usually reaches about 70 ° C. or higher. When supplying heat such as hot water,
The flow path switching valve 9 is connected between AB and the fuel cell 2.
Is supplied to the heat exchanger 21. The cooling water radiated through the heat exchanger 21 is supplied to the fuel cell 2 again by the cooling water circulation pump 6.

On the other hand, the low temperature side of the heat exchanger 21 is connected to the hot water storage tank 8 filled with city water. Water near the bottom is supplied to the heat exchanger 21 through the hot water circulation circuit 22 from the inlet of the hot water circulation circuit 22. The hot water stored at a high temperature after passing through the heat exchanger 21 enters the hot water storage tank 8 through the hot water circulation path discharge port 23. The hot water storage tank 8 is of a stacked type that stores hot water from above.
The high-temperature hot water stored therein is stored above the hot water storage tank 8. Hot water is supplied from a hot water supply port provided on the upper surface side of the hot water storage tank 8 to an external heat load such as a water heater or heating. The hot water stored at a low temperature by supplying heat to the external heating load returns to the inside of the hot water storage tank 8 from the hot water storage heating load return port 27 located at the middle position of the hot water storage tank 8. When the hot water is reduced by hot water supply, city water is supplied from a supply port provided on the bottom side of the hot water storage tank 8.

In this embodiment, the hot water circulation path 22
Has a configuration in which hot water flows by natural convection, but a pump (not shown) for supplying hot water to the heat exchanger 21.
Is also effective in the hot water circulation path 22.

When the hot water is sufficiently stored in the hot water storage tank 8, the cooling water passing through the fuel cell 2 is circulated to the radiator 11 by operating the flow path switching valve 9, and the cooling water is cooled. Of heat from the system.

According to the present embodiment, for example, the operating temperature of a polymer electrolyte fuel cell is generally about 80 ° C., so that the temperature of hot water stored in hot water storage tank 8 is as high as 60 ° C. or higher. The temperature of the hot water stored in the hot water storage tank 8 filled with city water is about 20 ° C. Since the hot water storage tank 8 is of a stacked type, a high-temperature hot water area is formed inside the hot water storage tank 8 and a low-temperature hot water area is formed below the hot water tank 8, and the temperature gradient is maintained. Therefore,
While the fuel cell 2 is operating, the water inside the hot water storage tank 8 contains
A layered structure of high hot water and low hot water is formed, and when no hot water is supplied, the high temperature layer located above gradually increases.

When supplying hot water to the external hot water supply load, the hot water stored from the hot water supply port above the hot water storage tank 8 is supplied to the external hot water supply load, and at the same time, city water is supplied from the bottom side. While the fuel cell 2 is operating, hot water is stored from above the hot water storage tank 8. Water is supplied and discharged from a plurality of locations in the hot water storage tank 8, but the hot water and the low temperature hot water formed by the temperature gradient are maintained in a layered structure, so the hot water is always supplied from above the hot water storage tank 8. can do.

When hot water is supplied to an external heating load, the hot water is generally radiated by heat exchange with the heating load. Therefore, a large amount of heat is required at the time of starting the heating load, and accordingly, the temperature of the hot water returned to the hot water heating load return port 27 decreases. Also, during the steady operation of the heating load, a smaller amount of heat is required than at the time of startup, so that the temperature of the hot water returned to the hot water storage load return port 27 becomes higher than at the time of startup. In addition, the temperature of the stored hot water that returns at both startup and steady times is higher than city water. Even in such a case, the hot water returned to the hot water storage tank 8 from the hot water storage heating load return port 27 provided in the middle of the hot water storage tank 8 has a density difference caused by a temperature difference with the hot water stored in the hot water storage tank 8. Accordingly, hot water is stored at an appropriate hot water temperature range according to the temperature distribution inside the hot water storage tank 8. Thereby, large convection from the bottom of the hot water storage tank 8 as in the conventional example shown in FIG. 4 can be prevented, and the high-temperature hot water stored above the hot water storage tank 8 can be externally stirred without being heated at a high temperature. Can be used for heat load and can store hot water.

As described above, according to the present embodiment, there is provided a fuel cell cogeneration system capable of stably supplying hot water in a short time and easily coping with fluctuations in the heat output of the fuel cell. be able to.

The outlet of the hot water circulation circuit of the present embodiment is an example of the second supply port of the hot water circulation circuit of the present invention, and the suction port of the hot water circulation circuit of the present embodiment is the first supply port of the hot water circulation circuit of the present invention. This is an example of the supply port, the supply port of the present embodiment is an example of the hot water supply port of the present invention, and the hot water supply heating load return port of the present embodiment is an example of the return hot water supply port of the present invention.

[0075]

As is apparent from the above description, the present invention can provide a fuel cell cogeneration system capable of supplying hot water to an external load in a short time from the start of operation.

Further, the present invention can provide a fuel cell cogeneration system capable of stably supplying hot water to an external load.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a fuel cell cogeneration system according to a first embodiment.

FIG. 2 is a configuration diagram showing a fuel cell cogeneration system according to a second embodiment.

FIG. 3 is a configuration diagram illustrating a fuel cell cogeneration system according to Embodiment 2.

FIG. 4 is a configuration diagram showing a conventional fuel cell cogeneration system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel gas generation part 2 Fuel cell 3 Fuel gas humidifier 4 Oxidant gas humidifier 5 Inverter 6 Cooling water circulation pump 7 Cooling water circulation path 8 Hot water storage tank 9 Flow path switching valve 10 Heat exchanger 11 Radiator 21 Heat exchanger 22 Hot water storage Water circulation channel 23 Hot water circulation channel outlet 24 Hot water circulation pump 25 Thermistor 26 Control unit 27 Hot water heating load return port

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuya Ueda 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 72) Inventor Masataka Ozeki 1006 Kazuma Kadoma, Kazuma, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd.

Claims (6)

[Claims] 1. A fuel cell comprising: a fuel cell for generating electric power and heat using a fuel gas and an oxidizing gas; and a hot water tank for storing heat generated by the fuel cell as hot water, wherein the hot water tank has an external hot water supply load. And / or a hot water supply port for supplying hot water to an external heating load is provided at an upper portion, and the hot water storage tank is configured to supply the hot water so that hot water located above is hotter than hot water located below. A fuel cell cogeneration system characterized by storing. 2. A heat transport medium circulation path for circulating a heat transport medium for recovering the generated heat, a heat exchanger for transferring the heat recovered by the heat transport medium to hot and cold water in the hot water storage tank, A hot-water storage circuit that circulates hot-water from the hot-water storage tank to the heat exchanger, wherein the hot-water storage tank has a first hot-water storage circuit supply port for supplying hot water to the hot-water storage tank to the hot-water storage circuit; A hot water circulation path second supply port for supplying the hot water returned from the water circulation path to the hot water storage tank; and the hot water circulation path second supply port is provided with the hot water circulation path first.
2. The fuel cell cogeneration system according to claim 1, wherein the fuel cell cogeneration system is provided above the supply port and below the hot water supply port. 3. The hot water tank has a hot water supply port for supplying hot water to the hot water tank, and the hot water supply port is provided below the second hot water circulation path supply port. The fuel cell cogeneration system according to claim 2, wherein: 4. The hot water tank supplies hot water to the external heating load, and the hot water tank has a return hot water supply port for returning hot water discharged from the external heating load to the hot water tank. The hot water supplied at a predetermined height position of the hot water storage tank, wherein the predetermined height position is a temperature at which the temperature of the hot water stored in the hot water storage tank at the predetermined height position is supplied from the return hot water supply port. The fuel cell cogeneration system according to any one of claims 1 to 3, wherein the height position is substantially the same as the temperature of the fuel cell. 5. A pump for circulating water in the hot water circulation path, a temperature detector for detecting a temperature of water passing through the heat exchanger in the hot water circulation path downstream of the heat exchanger, 5. A pump capacity control means for adjusting a water flow rate of the hot water circulation circuit based on the detected temperature by increasing or decreasing a capacity of a pump.
The fuel cell cogeneration system according to any one of the above. 6. The fuel cell cogeneration system according to claim 5, wherein the pump capacity control means adjusts the water flow rate so that the detected temperature becomes constant.