JP7526067B2 - Fuel Cell Systems - Google Patents

Description

This disclosure relates to a fuel cell system.

There is a known fuel cell system that supplies hot water by using the electricity generated by a fuel cell module and the exhaust heat generated by the fuel cell module. The exhaust heat from the fuel cell module is utilized via a heat medium that exchanges heat with the high-temperature exhaust gas generated when the fuel cell module generates electricity (see Patent Document 1).

JP 2018-195452 A

The heat transfer medium that has undergone heat exchange is temporarily stored in a heat storage tank, and the heat stored in the heat transfer medium is extracted at the desired time, such as when a user needs to supply hot water. Therefore, it is necessary to maintain the temperature of the heat transfer medium stored in the heat storage tank at or above the design temperature.

Therefore, the purpose of this disclosure, which has been made in consideration of the problems with the conventional technology described above, is to provide a fuel cell system that suppresses the temperature drop of the heat transfer medium in the heat storage tank.

In order to solve the above-mentioned problems, a fuel cell system according to a first aspect of the present invention comprises:
A fuel cell module;
A water heater capable of supplying hot water;
and a heat storage tank located above the fuel cell module for storing a heat transfer medium that exchanges heat with exhaust gas discharged from the fuel cell module and is supplied directly to the water heater, or a heat transfer medium that exchanges heat with water supplied directly or indirectly to the water heater .

The fuel cell system according to the present disclosure configured as described above suppresses the temperature drop of the heat transfer medium in the heat storage tank.

1 is a schematic configuration diagram of a fuel cell system according to an embodiment of the present invention. 2 is a cross-sectional view taken along the vertical direction of the support portion, showing the arrangement of the fuel cell module, the heat storage tank, and the water heater 13 in FIG. 1 .

Below, an embodiment of a fuel cell system to which the present disclosure is applied is described with reference to the drawings.

As shown in FIG. 1, a fuel cell system 10 according to an embodiment of the present disclosure includes a fuel cell module 11, a heat storage tank 12, and a water heater 13. The fuel cell system 10 may further include a heat medium circulation path 14, a radiator 15, a heat medium pump 16, a gas supply path 17, a water supply path 18, and an exhaust port 19. As shown in FIG. 2, the fuel cell system 10 may further include a support portion 20.

The fuel cell module 11 may have a reformer and a cell stack. The reformer generates fuel such as hydrogen by causing a steam reforming reaction between gas supplied as raw fuel and water. The cell stack generates electricity through an electrochemical reaction using an oxidant such as oxygen contained in the air and the fuel generated by the reformer. The cell stack also generates water through an electrochemical reaction. Unreacted fuel and unreacted oxidant discharged from the cell stack are combusted to provide energy for the steam reforming reaction in the reformer. The water discharged from the cell stack is discharged from the fuel cell module 11 in a high-temperature gaseous state together with the combustion gas resulting from the combustion of the unreacted fuel and unreacted oxidant.

The exhaust gas discharged from the fuel cell module 11 may contain combustion gas and gaseous water. As shown in FIG. 1, the exhaust gas discharged from the fuel cell module 11 may be heat exchanged with a heat medium using a heat exchanger 21. The exhaust gas cooled by the heat exchange may be separated into gaseous exhaust gas and condensed liquid water by a gas-liquid separator 22. The separated exhaust gas may be discharged to the outside of the fuel cell system 10 via the exhaust port 19. The separated water may be temporarily stored in a water tank 23 and then sent to the fuel cell module 11 as water to be used in the steam reforming reaction.

The heat storage tank 12 stores a heat medium. The heat medium is used for heat exchange with the exhaust gas discharged from the fuel cell module 11. The heat medium is, for example, a fluid with a large specific heat, such as water or antifreeze. In this embodiment, the heat medium is water. The heat medium stored in the heat storage tank 12 may be circulated between the heat storage tank 12 and the heat exchanger 21.

As shown in FIG. 2, the heat storage tank 12 is located above the fuel cell module 11. Above in the fuel cell system 10 means the same direction as vertically above the ground when the fuel cell system 10 is installed in a predetermined ideal posture. Above the fuel cell module 11 means that the position in the up-down direction is limited to the upper side, and the position in a plane perpendicular to the up-down direction is arbitrary. Furthermore, the heat storage tank 12 may be located above the fuel cell module 11. Above the fuel cell module 11 means that the position in the up-down direction is the upper side, and that the positions in the plane perpendicular to the up-down direction overlap.

As shown in FIG. 1, the water heater 13 can supply hot water by using the heat medium stored in the heat storage tank 12. The water heater 13 can supply hot water by, for example, heating water by heat exchange with the heat medium. Alternatively, in a configuration in which the heat medium is water, the heat medium may be directly supplied as hot water. The water heater 13 may have a burner that burns gas, and may be capable of heating using the burner when the heat medium alone is insufficient. The burner may heat the water by burning gas supplied as fuel. Exhaust gas from the combustion may be discharged from the water heater 13.

As shown in FIG. 2, the water heater 13 may be positioned so as to be aligned with the heat storage tank 12 in a direction perpendicular to the up-down direction. The water heater 13 may be positioned close to the heat storage tank 12.

As shown in FIG. 1, the heat medium circulation path 14 may circulate the heat medium between the heat storage tank 12 and the heat exchanger 21. A part of the heat medium circulation path 14 may be connected to the heat exchanger 21 via the radiator 15 and the heat medium pump 16. The heat medium circulation path 14 may have a first part 24 and a second part 25 between the heat medium pump 16 and the heat exchanger 21. The first part 24 may extend upward from the discharge port of the heat medium pump 16. The upward direction may include not only a vertical upward direction but also an oblique upward direction. The second part 25 may extend downward from the first part 24. The downward direction may include not only a vertical downward direction but also an oblique downward direction. The extension is not limited to a linear extension, and may be a curved extension.

The radiator 15 may cool the heat medium extracted from the heat storage tank 12, in other words, the heat medium before heat exchange with the exhaust gas of the fuel cell module 11. The radiator 15 may have, for example, a fan with an adjustable rotation speed. The radiator 15 may be capable of adjusting the cooling of the heat medium by adjusting the rotation speed of the fan.

The heat medium pump 16 may supply the heat medium to the heat exchanger 21 by increasing the pressure of the heat medium.

The gas supply path 17 may have a single or multiple gas intake ports 26. The gas intake port 26 may branch into at least two branches. The branched gas supply path 17 may be connected to the fuel cell module 11 and the water heater 13. The gas supply path 17 may supply gas to the fuel cell module 11 and the water heater 13 via the gas intake port 26.

The water supply path 18 may have a single or multiple water intake ports 27. The water intake port 27 may be branched into at least two branches. The branched water supply path 18 may be directly or indirectly connected to the fuel cell module 11 and the water heater 13. Specifically, the water supply path 18 may be indirectly connected to the fuel cell module 11 via a water tank 23. Furthermore, the water supply path 18 may be connected to the water tank 23 via a purification device that purifies the water. Furthermore, the water supply path 18 may be directly connected to the water heater 13. The water supply path 18 may supply water to the fuel cell module 11 and the water heater 13 via the water intake port 27.

As shown in FIG. 2, the gas intake port 26 and the water intake port 27 may be located at a different position in the vertical direction from the hot water supply port 28 from the water heater 13. More specifically, the gas intake port 26 and the water intake port 27 may be located below the fuel cell module 11. Also, the hot water supply port 28 may be located below the water heater 13 and above the fuel cell module 11.

As shown in FIG. 1, the exhaust port 19 may be directly or indirectly connected to the fuel cell module 11 and the water heater 13. Specifically, the exhaust port 19 may be indirectly connected to the fuel cell module 11 via the gas-liquid separator 22. The exhaust port 19 may also be directly connected to the water heater 13. The exhaust port 19 may exhaust exhaust gas discharged from the fuel cell module 11 and exhaust gas discharged from the water heater 13 from the fuel cell system 10. The exhaust port 19 may exhaust exhaust air, which is air heated by the radiator 15 through heat exchange for cooling the heat medium.

As shown in FIG. 2, the support unit 20 may support the heat storage tank 12 at a fixed position relative to the fuel cell module 11. The support unit 20 may be, for example, a part of a housing that houses the fuel cell module 11, the heat storage tank 12, and the water heater 13. The support unit 20 is not limited to a housing, and may be a framework, a fixing bracket, a plate, or the like that can support the heat storage tank 12 at a fixed position relative to the fuel cell module 11. The fuel cell system 10 may be installed in a pipe shaft of an apartment building or the like, and the support unit 20 may support at least the heat storage tank 12 at the above-mentioned position within the pipe shaft.

The support portion 20 may be provided with rails. The rails allow at least a portion of the fuel cell module 11, the heat storage tank 12, and the water heater 13 to be pulled out in one direction perpendicular to the up-down direction, either separately or together.

The support portion 20 may have a spacer at its lower end in the vertical direction. The spacer may be, for example, three or more legs. The vertical length of the spacer may be longer than the height of the gas meter and water meter used in the facility in which the fuel cell system 10 is expected to be installed.

In the fuel cell system 10 of this embodiment configured as described above, the heat storage tank 12 is located above the fuel cell module 11. With this configuration, in the fuel cell system 10, the heat dissipated from the fuel cell module 11, which operates at high temperatures, is easily conducted upward by convection, so that the heat storage tank 12 can be heated. Therefore, the fuel cell system 10 can suppress the temperature drop of the heat medium in the heat storage tank 12. Also, with the above configuration, in the fuel cell system 10, outside the facility where it is installed, the outlet for the heat medium from the heat storage tank 12 can be located away from the ground or floor by at least the height of the fuel cell module 11. Therefore, in the fuel cell system 10, it is easy to directly extract and use the heat medium in the heat storage tank 12.

In addition, in the fuel cell system 10 of this embodiment, the heat storage tank 12 is located above the fuel cell module 11. With this configuration, the fuel cell system 10 can further suppress the temperature drop of the heat medium in the heat storage tank 12.

In addition, in the fuel cell system 10 of this embodiment, the water heater 13 is positioned so as to be aligned with the heat storage tank 12 in a direction perpendicular to the up-down direction. With this configuration, in the fuel cell system 10, the heat storage tank 12 can be heated by heat released from the water heater 13 when the water heater 13 is operating. Therefore, the fuel cell system 10 can further suppress the temperature drop of the heat medium in the heat storage tank 12.

The fuel cell system 10 of this embodiment also includes a common exhaust port 19 for exhausting the exhaust gas discharged from the fuel cell module 11 and the exhaust gas discharged from the water heater 13. With this configuration, the fuel cell system 10 can be made smaller than a configuration in which separate exhaust ports are provided. With the above-described configuration, the fuel cell system 10 mixes the high-temperature exhaust gas discharged from the water heater 13 with the exhaust gas cooled by the heat transfer medium in the fuel cell module 11. Therefore, the fuel cell system 10 exhausts low-temperature exhaust gas, suppressing the generation of white smoke when the surroundings are at low temperatures and improving safety near the exhaust port 19.

In addition, in the fuel cell system 10 of this embodiment, the exhaust port 19 discharges the exhaust gas from the radiator 15. The exhaust temperature of the radiator 15 is generally lower than the temperature of the exhaust gas from the water heater 13. Therefore, with the above-mentioned configuration, the fuel cell system 10 can further lower the temperature of the high-temperature exhaust gas discharged from the water heater 13 before discharging it.

In addition, in the fuel cell system 10 of this embodiment, the gas supply path 17 branches off from the gas intake port 26 to supply gas to the fuel cell module 11 and the water heater 13, and the water supply path 18 branches off from the water intake port 27 to supply water to the fuel cell module 11 and the water heater 13. With this configuration, the fuel cell system 10 can be simplified in configuration and manufacturing costs can be reduced.

In addition, in the fuel cell system 10 of this embodiment, the supply path of the heat medium from the heat medium pump 16 to the heat exchanger 21 has a first portion 24 extending upward from the discharge port of the heat medium pump 16 and a second portion 25 extending downward from the first portion 24. With this configuration, the fuel cell system 10 can improve drainage while reducing the possibility of air being mixed in the heat medium pump 16.

Furthermore, in the fuel cell system 10 of this embodiment, rails are provided on the support portion 20. With this configuration, when the fuel cell system 10 is installed in a pipe shaft of an apartment building, the fuel cell module 11, heat storage tank 12, water heater 13, etc. can be easily moved outside the pipe shaft. Therefore, the fuel cell system 10 can facilitate the maintenance and management of the fuel cell module 11, heat storage tank 12, water heater 13, etc.

In addition, in the fuel cell system 10 of this embodiment, the support portion 20 has legs that are longer than the height of the gas meter and water meter. This configuration prevents the components of the fuel cell system 10 from being installed at the same height as the gas meter and water meter. Therefore, the fuel cell system 10 can facilitate the maintenance and management of each component without interfering with the gas meter and water meter, which are difficult to move temporarily.

In addition, in the fuel cell system 10 of this embodiment, the gas intake port 26 and the water intake port 27 are located at a different position in the vertical direction from the hot water supply port 28 from the water heater 13. With this configuration, the fuel cell system 10 can reduce the area in which the gas intake port 26, the water intake port 27, and the hot water supply port 28 are installed in the direction perpendicular to the vertical direction, compared to a configuration in which they are all located at the same position.

Although the present disclosure has been described based on various drawings and examples, it should be noted that a person skilled in the art would easily be able to make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these modifications and corrections are included within the scope of the present invention.

REFERENCE SIGNS LIST 10 fuel cell system 11 fuel cell module 12 heat storage tank 13 water heater 14 heat medium circulation path 15 radiator 16 heat medium pump 17 gas supply path 18 water supply path 19 exhaust port 20 support portion 21 heat exchanger 22 gas-liquid separator 23 water tank 24 first portion 25 second portion 26 gas intake port 27 water intake port 28 hot water port

Claims (9)

A fuel cell module;
A water heater capable of supplying hot water;
a heat storage tank located above the fuel cell module, which exchanges heat with exhaust gas discharged from the fuel cell module and stores a heat medium to be directly supplied to the water heater, or a heat medium to be heat exchanged with water directly or indirectly supplied to the water heater . 2. The fuel cell system according to claim 1,
The heat storage tank is located above the fuel cell module. 3. The fuel cell system according to claim 1,
The water heater is positioned so as to be aligned with the heat storage tank in a direction perpendicular to the up-down direction. 4. The fuel cell system according to claim 1,
The fuel cell system further comprises an exhaust port for discharging exhaust gas discharged from the fuel cell module and exhaust gas discharged from the water heater. 5. The fuel cell system according to claim 4,
a radiator for cooling the heat transfer medium before heat exchange with the exhaust gas of the fuel cell module;
The exhaust port discharges exhaust gas from the radiator. 6. The fuel cell system according to claim 1,
a gas supply path that branches from the gas intake port and supplies gas to the fuel cell module and the water heater;
the fuel cell system further comprising a water supply passage branching from the water intake port to supply water to the fuel cell module and the water heater. 7. The fuel cell system according to claim 1,
The fuel cell system further comprises a support portion for supporting the heat storage tank at a determined position relative to the fuel cell module. 8. The fuel cell system according to claim 7,
A fuel cell system, wherein the support portion is a part of a housing that houses the fuel cell module, the heat storage tank, and the water heater. 9. The fuel cell system according to claim 1,
a heat medium pump that supplies the heat medium to a heat exchanger that exchanges heat with the exhaust gas of the fuel cell module;
a supply passage from the heat medium pump to the heat exchanger having a first portion extending upward from a discharge port of the heat medium pump and a second portion extending downward from the first portion.

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