JP7393141B2 - fuel cell device - Google Patents

Description

The present disclosure relates to a fuel cell device.

Equipped with a fuel cell that generates electricity and an exhaust heat recovery system that collects and stores waste heat from the fuel cell in a heat medium, it combines the power output from the fuel cell with the power supplied from the grid power source and generates an external power source. Fuel cell devices that supply a load are known. Furthermore, there is also known a fuel cell device that performs self-sustaining operation in which only the power generated by the fuel cell is supplied to an external load when the power supply from the grid power supply is stopped due to a power outage (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2017-098153

In conventional fuel cell devices, the temperature of the heat medium increases during self-sustaining operation, which may reduce the durability and reliability of the fuel cell device.

A fuel cell device of the present disclosure includes a fuel cell that generates electricity,
a heat storage tank that stores a heat medium that has been heat exchanged with the exhaust heat of the fuel cell;
a control device that controls the operation of the fuel cell;
A hot water tapping device that taps hot water using the heat stored in the heat storage tank,
The control device is capable of executing a power generation suppressing operation in which power generation is performed at a lower output than the rated power when a power generation suppressing condition is satisfied during the self-sustaining operation, and when an operation instruction for the hot water tapping device is given during the self-sustaining operation. , a hot water tap control that executes the operation of the hot water tap device.

According to the fuel cell device of the present disclosure, during self-sustaining operation, the temperature of the heat medium can be suppressed from increasing, and the durability and reliability of the fuel cell device can be improved.

1 is a schematic configuration diagram of a fuel cell device according to an embodiment. FIG. 2 is a perspective view showing the configuration of the fuel cell device inside the outer case. 7 is a flowchart illustrating an example of control according to the embodiment. It is a flow chart which shows another example of control of an embodiment. It is a flow chart which shows heating medium high temperature suppression control. It is a flow chart which shows another example of control of an embodiment. 3 is a flowchart showing fuel cell high temperature suppression control. It is a flowchart which shows continuation determination control.

Hereinafter, a fuel cell device according to an embodiment of the present disclosure will be described using the drawings. FIG. 1 is a schematic configuration diagram of a fuel cell device according to an embodiment, and FIG. 2 is a perspective view showing the configuration of the fuel cell device inside an outer case.

The fuel cell device 100 of the embodiment includes a fuel cell 11, a heat storage tank 3, a control device 30, and a hot water tapping device 60.

The fuel cell 11 generates power using fuel gas and air. The fuel cell 11 may have a cell stack structure including a plurality of fuel cells. The fuel cell may be a solid oxide fuel cell. The fuel cell device 100 includes a fuel cell module (also referred to as a module) 1 that stores a fuel cell 11 and a reformer 12 in a storage container 10 .

Air used for power generation is introduced into the fuel cell 11 via an air supply device 14 that includes an air blower B2, an air flow meter AM1, and a pipe A that is an air flow path. As the air flow meter AM1, a known flow meter such as an air flow meter can be used. The fuel gas used for power generation is supplied to the reformer together with reformed water for reforming the fuel gas via a fuel gas supply device 15 that includes a fuel gas pump B1 and a pipe G that is a raw fuel gas flow path. introduced in 12.

The fuel cell device 100 includes a first temperature measuring section TM1 that measures the temperature of the fuel cell 11. As the first temperature measuring section TM1, a known temperature measuring device such as a thermocouple can be used. In this embodiment, the temperature at the center position of the fuel cell 11 is measured by the first temperature measuring section TM1 as a representative value of the temperature of the fuel cell 11.

The fuel cell device 100 includes a first heat exchanger 2, a heat storage tank 3 that stores a heat medium such as water, a heater 4, a heat medium pump P1 that circulates the heat medium from the heat storage tank 3, and flow path piping that connects these. It is equipped with a first heat circulation system HC1 which is an exhaust heat recovery system. For example, as shown in FIG. 1, the first heat exchanger 2, heater 4, and heat storage tank 3 are provided in this order in the direction of circulation of the heat medium in the first thermal circulation system HC1.

In the first heat exchanger 2, the exhaust gas (also referred to as exhaust heat) of the fuel cell 11 and the heat medium exchange heat, and moisture contained in the exhaust gas condenses to produce condensed water. The generated condensed water is collected via the condensed water channel C and stored in the reformed water tank 6. The exhaust gas from which moisture has been removed is exhausted to the outside of the device via the exhaust gas flow path E. The reformed water stored in the reformed water tank 6 is supplied to the reformer 12 via the reformed water flow path R and the reformed water pump P3, and is used for steam reforming of the fuel gas. The heat storage tank 3 stores a heat medium that has undergone heat exchange with the exhaust heat of the fuel cell 11 . The heater 4 provides heat to the heating medium circulating in the first thermal circulation system HC1. For example, as shown in FIG. 1, the heater 4 is located downstream of the first heat exchanger 2 and upstream of the heat storage tank 3 in the heat medium circulation direction.

The fuel cell device 100 includes a second temperature measurement section TM2 that measures the temperature of the heat medium stored in the heat storage tank 3. As the second temperature measuring section TM2, a known temperature measuring device such as a thermistor can be used. In this embodiment, the temperature of the heat medium at the bottom of the heat storage tank 3 is measured by the second temperature measuring section TM2.

The fuel cell device 100 includes a third temperature measurement section TM3 and a fourth temperature measurement section TM4 that measure the temperature of the heat medium circulating in the first thermal circulation system HC1. As the third temperature measuring section TM3 and the fourth temperature measuring section TM4, known temperature measuring devices such as a thermistor can be used. In this embodiment, the temperature of the heating medium at the outlet of the heater 4, that is, downstream of the heater 4 and upstream of the heat storage tank 3 in the heating medium circulation direction, is measured by the third temperature measuring section TM3. Further, in this embodiment, the temperature of the heat medium downstream of the heat storage tank 3 and upstream of the first heat exchanger 2 in the circulation direction of the heat medium is measured by the fourth temperature measuring section TM4.

The fuel cell device 100 includes a second heat circulation system HC2, which is an exhaust heat recovery system including a second heat exchanger 5, a heating pump P2 that circulates a heat medium from a heat storage tank 3, and flow pipes connecting these. We are prepared. In the second heat exchanger 5, the high temperature heat medium stored in the heat storage tank 3 and the low temperature tap water supplied from the water supply via the supply channel Kin exchange heat. The tap water (also referred to as hot water) heated by the second heat exchanger 5 is supplied to the hot water tapping device 60 via the supply channel Kout. The supply flow path Kin has a fifth temperature measurement section TM5 that measures the temperature of tap water supplied from the water supply. As the fifth temperature measuring section TM5, a known temperature measuring device such as a thermistor can be used.

The hot water tapping device 60 taps hot water using the heat stored in the heat storage tank 3. The hot water dispenser 60 dispenses hot water supplied via the supply channel Kout to, for example, a bath, kitchen, washstand, etc. in the home. The hot water is used for domestic purposes.

The fuel cell device 100 may further include various configurations necessary for generating electricity, tapping hot water, and the like. Each of the configurations shown above is an example, and any configurations other than those required for various controls described below are arbitrary.

In addition to the fuel cell module 1, the fuel cell device 100 includes a power conditioner 20, a control device 30, an operation board 40 including a display device and an operation panel, etc. as auxiliary equipment that assists the power generation operation. The power conditioner 20 connects the power generated by the fuel cell 11 with a grid power source and supplies it to an external load. The power conditioner 20 can detect when the power supply from the grid power source has stopped. The fuel cell device 100 is disposed in a case 50 including frames 51 and exterior panels 52, as shown in FIG. 2, for example.

The fuel cell device 100 includes a control device 30 that includes at least one processor, a storage device, and the like to provide control and processing capabilities to perform various functions, as described in detail below.

According to various embodiments, at least one processor may be implemented as a single integrated circuit or as multiple communicatively connected integrated and/or discrete circuits. The at least one processor can be implemented according to a variety of known techniques.

In one embodiment, a processor includes one or more circuits or units configured to perform one or more data calculation procedures or processes, for example, by executing instructions stored in an associated memory. In other embodiments, the processor may be a firmware, such as a discrete logic component, configured to perform one or more data calculation procedures or processes.

According to various embodiments, the processor includes one or more processors, controllers, microprocessors, microcontrollers, application specific integrated circuits, digital signal processing units, programmable logic devices, field programmable gate arrays, or any of these devices or Any combination of configurations or other known devices and configurations may be included to perform the functions described below.

The control device 30 is connected to a storage device, a display device (both not shown), various components and various sensors that constitute the fuel cell device 100, and controls the entire fuel cell device 100, including each of these functional parts. Control and manage. The control device 30 obtains a program stored in a storage device attached to the control device 30, and executes this program to realize various functions related to each part of the fuel cell device 100.

When transmitting control signals or various information from the control device 30 to other functional units or devices, the control device 30 and the other functional units may be connected by wire or wirelessly. The control performed by the control device 30 that is characteristic of this embodiment will be described later. In this embodiment, the control device 30 controls various auxiliary devices such as the fuel gas pump B1 based on instructions and commands from external devices connected to the fuel cell device, and instructions and measured values from the various sensors described above. Control. In the figures, illustration of connection lines connecting the control device 30 and each device and each sensor that constitute the fuel cell may be omitted.

A storage device (not shown) can store programs and data. The storage device may also be used as a work area for temporarily storing processing results, and stores flags used in heat medium high temperature suppression control and fuel cell high temperature suppression control, which will be described later. The storage device includes a recording medium. The recording medium may include any non-transitory storage medium, such as semiconductor storage media and magnetic storage media. Further, the storage device may include multiple types of storage media. The storage device may include a combination of a portable storage medium, such as a memory card, an optical disk, or a magneto-optical disk, and a storage reader. The storage device may include a storage device used as a temporary storage area, such as a RAM (Random Access Memory).

Note that the control device 30 and storage device of the fuel cell device can also be realized as a configuration provided outside the fuel cell device 100. Furthermore, it is also possible to realize it as a control method including characteristic control steps in the control device 30 according to the present disclosure, or to realize it as a control program for causing a computer to execute the above steps.

The control device 30 controls the power generation operation of the fuel cell 11 by appropriately switching between a plurality of operation modes. The plurality of operation modes include a normal operation mode and a self-sustaining operation mode.

In the normal operation mode, the power generation operation of the fuel cell 11 is controlled when power supply from the grid power source continues. Normal operating modes include rated operating modes and part load operating modes. The rated operation mode is an operation mode in which the power generation operation is performed at the rated power generation power (also referred to as the first output) W1, and the fuel cell is 11 is supplied with fuel gas and air, and is operated to produce the first output W1. The partial load operation mode is an operation mode in which the output is varied according to changes in the external load.

The self-sustaining mode controls the self-sustaining operation of the fuel cell 11 when power supply from the grid power supply is stopped due to a power outage or the like. When the power conditioner 20 detects that the power supply from the grid power supply has stopped, the control device 30 temporarily stops the output to the external load, but changes the power generation operation of the fuel cell 11 from the normal operation mode. By switching to the self-sustaining mode, it is possible to resume output to the external load.

When the self-sustaining operation is started, the control device 30 increases the flow rate of the fuel gas supplied to the module 1 in order to restore the output of the fuel cell device, and performs power generation operation at the first output W1 using the internal load. The fuel cell 11 is controlled accordingly. The heater 4 of the first thermal circulation system HC1 is used as the internal load. After confirming that power generation operation can be performed at the first output W1, the control device 30 restarts output to the external load. When outputting to an external load, priority is given to outputting to the hot water tapping device 60.

In this manner, during self-sustaining operation, the control device 30 increases the flow rate of the fuel gas supplied to the module 1. Therefore, surplus fuel gas that is not used for power generation is likely to be generated, and the amount of heat flowing into the first heat exchanger 2 increases. Furthermore, since the heater 4 is used as an internal load, the heat medium is heated by the heat generated by the heater 4, and the temperature of the heat medium tends to increase. Moreover, since excess fuel gas is burned in the combustion section between the fuel cell 11 and the reformer 12, the temperature of the fuel cell 11 also tends to increase.

Therefore, the control device 30 can perform a power generation suppression operation that suppresses the output in order to lower the temperature of the fuel cell device during the self-sustaining operation. The power generation suppression operation is executed when a predetermined power generation suppression condition is satisfied.

Moreover, the power generation suppression operation is to operate the fuel cell 11 at a second output W2 lower than the first output W1. In this embodiment, the second output W2 is set lower than the power consumption of the hot water tapping device 60. Since the second output W2 is lower than the power consumption of the hot water tapping device 60, the hot water tapping device 60 may not be able to perform the hot water tapping operation (also simply referred to as operation) during the power generation suppression operation. In other embodiments, even when the second output W2 is higher than the power consumption of the hot water tap device 60, the amount of power that can be supplied to other external loads is reduced by the amount of power output to the hot water tap device 60. . Therefore, when operating the hot water tap device 60, it is necessary to cancel the power generation suppression operation and restore the output of the fuel cell 11 to at least the output at which the hot water tap device 60 can operate, preferably to the first output W1. Note that the second output W2 only needs to be a lower output than the first output W1, and can be appropriately set depending on the size of the fuel cell device and the like. In this embodiment, when the power generation suppression operation is canceled, the output of the fuel cell 11 is controlled to recover from the second output W2 to the first output W1.

The power generation suppression conditions include a first condition regarding the temperature of the heat medium, and the control device 30 executes heat medium high temperature determination control to determine whether the first condition is satisfied. The first condition is, for example, that the temperature hTM3 of the heating medium measured by the third temperature measuring section TM3 is equal to or higher than the third predetermined temperature H3, or that the temperature hTM4 of the heating medium measured by the fourth temperature measuring section TM4 is higher than or equal to the third predetermined temperature H3. The third predetermined temperature H3 is higher than the third predetermined temperature H3. For example, H3 is at 70°C and H4 is at 50°C.

The first condition may be any condition related to the heat medium temperature, and may include temperature conditions other than those described above. For example, the temperature of a heat storage tank in which a large amount of heat medium is stored in the fuel cell device may be measured by the second temperature measuring section TM2, and may be added to the temperature conditions as the fifth predetermined temperature H5. Alternatively, a temperature condition may be added in which the temperature of the water entering the second heat exchanger 5 is measured by the fifth temperature measuring section TM5 and compared with the heat storage tank temperature measured by the second temperature measuring section TM2. For example, the fifth predetermined temperature H5 is 50°C.

When the control device 30 receives an instruction to operate the hot water tapping device 60 while executing the power generation suppressing operation in the self-sustaining operation, the control device 30 executes hot water tapping control according to the content of the operation instruction for the hot water tapping device 60.

When the hot water tapping conditions are met, the control device 30 cancels the power generation suppression operation, restores the output of the fuel cell 11 to the first output W1, and then operates the hot water tapping device 60. Thereby, the heat medium can be cooled by replacing the heat medium with tap water or by exchanging heat with the tap water. As a result, the durability and reliability of the fuel cell device 100 can be improved. Further, by operating the hot water tapping device 60, the convenience of the fuel cell device 100 can be improved.

In the present embodiment, when the control device 30 is performing the power generation suppression operation in a state where the first condition is satisfied, the control device 30 is configured to forcibly discharge (discharge) hot water into the bath in order to cool the heat medium. is configured to allow. Hereinafter, forced access to the bath will be referred to as forced access to the bath. In this embodiment, this forced hot water tapping is also included in the execution of the operation of the hot water tapping device 60. Note that instructions regarding forced hot water dispensing may be set in advance using a remote control or the like, or may be made to be selected by the user each time. For example, if the user is to make a selection each time, the operation board 40 executes a notification to make the user select whether or not to forcefully dispense hot water. When the user wants to permit forced hot water dispensing, he turns on the forced hot water dispensing permission setting on the operation board 40, and when he does not want to permit forced hot water dispensing, he turns off the forced hot water dispensing permission setting. Note that if the user does not operate the forced hot water tap permission setting for a certain period of time, the forced hot water tap setting can be considered to be off.

When the user allows forced hot water supply, the high-temperature heat medium stored in the heat storage tank 3 and the low-temperature tap water supplied from the water supply via the supply flow path Kin are forced into the second heat exchanger 5. heat exchanged. Therefore, since the heat medium can be cooled, the durability and reliability of the fuel cell device 100 can be improved. Further, the power generation suppression operation due to the high temperature of the heat medium can be canceled, and the fuel cell 11 can be operated at the first output W1, so the convenience of the fuel cell device 100 can be improved.

Note that the forced hot water dispensing can be stopped when a predetermined amount of hot water is dispensed. Further, as another method of stopping, it is also possible to stop based on the fact that the first condition is no longer satisfied. In this case, one or more temperature measuring sections may be selected from the second temperature measuring section TM2, the third temperature measuring section TM3, the fourth temperature measuring section TM4, and the fifth temperature measuring section TM5, and separate temperature conditions may be provided. You can also stop it with . The hot water supply device 60 includes a hot water supply pipe to the bath and a solenoid valve (both not shown) provided in the hot water supply pipe, and the control device 30 outputs an electric signal to open and close this solenoid valve. Starts or stops forced hot water dispensing.

After stopping the operation of the hot water tapping device 60, the control device 30 may determine whether or not the power generation suppression condition is satisfied, and may execute (restart) the power generation suppression operation when the first condition is satisfied. Thereby, it is possible to suppress the temperature of the heat medium from increasing, and in turn, it is possible to improve the durability and reliability of the fuel cell device 100.

Further, if the power generation suppression condition is canceled while the hot water tap device 60 is in operation, the control device 30 determines whether to continue or stop the operation of the hot water tap device 60, depending on the type of operation instruction for the hot water tap device 60. Continuation determination control may be executed to In the continuation determination control, the control device 30 stops the operation of the hot water tap device 60 when the operation of the hot water tap device 60 is forced hot water tap. Thereby, unnecessary discharge of hot water can be suppressed. The control device 30 continues the operation of the hot water tapping device 60 when the operation of the hot water tapping device 60 is based on an instruction from the user. Thereby, the convenience of the fuel cell device 100 can be improved.

Further, the power generation suppression condition can also include a second condition regarding the temperature of the fuel cell 11. In this case, the control device 30 executes fuel cell high temperature determination control and determines whether the second condition is satisfied. The second condition is, for example, that the center temperature hTM1 of the fuel cell 11 measured by the first temperature measuring section TM1 is equal to or higher than the first predetermined temperature H1. For example, the first predetermined temperature H1 is 720°C.

Note that a second predetermined temperature H2 may be provided as a temperature condition for determining that the second condition is no longer satisfied after the second condition is satisfied. For example, the second predetermined temperature H2 is 700°C.

The second condition may be any condition related to the temperature of the fuel cell 11, and may include a plurality of conditions. For example, the condition may further include that the control device 30 is executing the air increase control and the air utilization rate Ua has reached its lower limit value Uamin. The air increase control is to increase the amount of air supplied to the fuel cell 11 and reduce the air utilization rate Ua of the fuel cell 11, thereby decreasing the temperature of the fuel cell 11. The lower limit value Uamin of the air utilization rate Ua is determined, for example, by the maximum flow rate according to the specifications of the air blower B2. If the air utilization rate Ua has not reached the lower limit value Uamin, the temperature of the fuel cell 11 can be lowered by lowering the air utilization rate Ua.

In the present embodiment, if the second condition is not satisfied, the control device 30 executes the power generation suppression operation and does not accept an operation instruction for the hot water tapping device 60. If the second condition is not met, by executing the power generation suppression operation without accepting an operation instruction for the hot water tapping device 60, it is possible to suppress the fuel cell 11 from becoming high temperature, thereby improving the durability of the fuel cell device 100. Reliability can be improved.

Therefore, the determination as to whether the second condition is satisfied can be performed before the determination as to whether the first condition is satisfied. For example, when determining whether the second condition is satisfied before determining whether the first condition is satisfied, the control device 30 determines whether the second condition is satisfied and the first condition is satisfied. In this case, an operation instruction for the hot water tapping device 60 can be accepted. Note that the operation of the hot water tapping device 60 is the same as that described above.

The power generation suppression operation control and hot water tapping control of this embodiment will be described below with reference to FIGS. 3 to 7.

FIG. 3 is a flowchart showing an example of this embodiment, and FIG. 4 is a flowchart showing another example of this embodiment. Note that in the flowcharts shown in FIGS. 3 and 4, the same control will be explained using FIG. 3. This flowchart starts when the power supply to the external load that was once stopped in the self-sustaining mode is restarted, and is continuously executed (loop) during the self-sustaining operation.

In [S1], it is determined whether the first condition determined based on the heat medium high temperature suppression control is satisfied.

In [S1], if the first condition is not satisfied (No), this flowchart ends. On the other hand, in [S1], if the first condition is satisfied [Yes], power generation suppression operation is executed in [S2], and the fuel cell 11 is operated at a second output W2 lower than the first output W1. Next, the process advances to [S3], and it is determined again whether the first condition is satisfied. If the first condition is not met, in other words, it means that the high temperature of the heat medium has been resolved, so the process proceeds to [S4], where the power generation suppression operation is canceled and the output of the fuel cell 11 is returned to the first output W1. After that, this flowchart ends. On the other hand, in [S3], if the first condition is satisfied again, the process then proceeds to [S5]. Note that the flow after [S5] is the part related to hot water tap control.

In [S5], the control device 30 determines whether or not forced hot water taping is permitted. If the forced hot water tap is set in advance and the conditions are met in [S3] and the forced hot water tap is permitted [Yes], proceed to [S6], cancel the power generation suppression operation, and then set the forced hot water tap ( (bathroom drain). When the predetermined forced hot water tapping is completed, this flowchart ends. In this embodiment, after the forced hot water tap is completed, the process may be returned to [S1] to determine whether the first condition is satisfied.

In [S5], if there is no permission for forced hot water supply [No], the process proceeds to [S7], and it is confirmed whether there is a hot water supply request from the user. If there is no hot water supply request from the user [No], the process returns to [S3] while continuing the power generation suppression operation, and it is again determined whether the first condition is satisfied.

On the other hand, in [S7], if there is a hot water supply request from the user [Yes], the process proceeds to [S8], cancels the power generation suppression operation, returns the output of the fuel cell 11 to the first output W1, and then Then, the process advances to [S9] and hot water is tapped. When the hot water supply based on the hot water supply request is completed, the process returns to [S1] again and it is determined whether the heat medium satisfies the first condition. This is because there are variations in the amount of hot water dispensed based on hot water supply requests from users, and it is not possible to determine whether the high temperature of the heating medium has been resolved, so the first condition is determined again.

Although the flowchart shown in FIG. 3 describes the flow when forced hot water is set in advance, it is also possible to confirm the forced hot water with the user each time. In the flowchart shown in FIG. 4, a user notification of forced hot water dispensing is provided as [S10] between [S3] and [S5]. After the notification in [S10], the flow proceeds to [S5] based on the user's selection result. The subsequent steps are the same as the flowchart shown in FIG.

FIG. 5 is a flowchart of heat medium high temperature determination control for determining whether the first condition, which is a condition for suppressing power generation, is satisfied. This flowchart starts when the power supply to the external load that was once stopped in the self-sustaining mode is restarted, and is continuously executed (loop) during the self-sustaining operation.

When the control is started, first in [S21], it is determined whether the flag F1 is 0 (off). The flag F1 is a flag indicating whether or not the first condition is satisfied. When the flag F1 is 0 (off), it indicates that the first condition is not satisfied. When the flag F1 is 1 (on), it indicates that the first condition is not satisfied. Indicates that the first condition is satisfied. Further, at the start of control, the flag F1 is 0 (off).

If the flag F1 is 0 (off) (Yes) in [S21], a determination is made to switch the flag F1 to 1 (on) in [S22] to [S23]. Further, if the flag F1 is 1 (on) or [No] in [S21], a determination is made in [S25] to [S27] to switch the flag F1 to 0 (off).

In [S21], if the flag F1 is 0 (off) [Yes], in [S22] it is determined whether the temperature hTM3 of the heat medium measured by the third temperature measurement unit TM3 is equal to or higher than the third predetermined temperature H3. Determine whether or not. In [S22], if hTM3 is equal to or higher than H3 (Yes), the process proceeds to [S24], switches the flag F1 to 1 (on), and ends the heat medium high temperature suppression control.

In [S22], if hTM3 is less than H3 (No), the process proceeds to [S23] and determines whether the temperature hTM4 of the heat medium measured by the fourth temperature measurement unit TM4 is equal to or higher than the fourth predetermined temperature H4. Determine. If hTM4 is equal to or higher than H4 (Yes) in [S23], the process proceeds to [S24], switches the flag F1 to 1 (on), and ends the heat medium high temperature suppression control. If hTM4 is less than H4 (No), the heating medium high temperature determination control is ended with the flag F1 being 0 (off).

Further, if the flag F1 is 1 (ON) in [S21] (No), the temperature hTM3 of the heating medium measured by the third temperature measuring section TM3 is lower than the third predetermined temperature H3 in [S25]. Determine whether it exists or not. If hTM3 is less than H3 [Yes], proceed to [S26]. If hTM3 is H3 or higher (No), the heating medium high temperature determination control is ended with the flag F1 being 1 (on).

Subsequently, in [S26], it is determined whether the temperature hTM4 of the heat medium measured by the fourth temperature measuring section TM4 is lower than the fourth predetermined temperature H4. If hTM4 is less than H4 [Yes], proceed to [S27]. If hTM4 is H4 or higher (No), the heating medium high temperature determination control is ended with the flag F1 being 1 (on).

Subsequently, in [S27], it is determined whether the temperature hTM of the heating medium measured by the second temperature measuring section TM2 is less than the fifth predetermined temperature H5. If hTM2 is less than H5 (Yes), the process proceeds to [S28], the flag F1 is switched to 0 (off), and the heating medium high temperature suppression control is ended. If hTM2 is H5 or higher (No), the heating medium high temperature determination control is ended with the flag F1 being 1 (on).

FIG. 6 is a flowchart showing another example of this embodiment. The flowchart is the same as the flowchart shown in FIG. 3, except that a determination as to whether the second condition is satisfied is added before determining whether the first condition is satisfied, and a description thereof will be omitted. This flowchart [starts] after the start of self-sustaining operation.

In [S11], it is determined whether a second condition determined based on fuel cell high temperature suppression control is satisfied.

In [S11], if the second condition is not satisfied [No], the process proceeds to [S1] and the first condition determined based on the heat medium high temperature suppression control described above is determined.

In [S11], if the second condition is satisfied [Yes], in [S12], a power generation suppression operation is executed in order to give priority to lowering the temperature of the fuel cell. In addition, access to hot springs will not be permitted. Note that the denial of permission may be either not executing the hot water tap even if the hot water tap request is accepted, or not accepting the hot water tap request itself. In [S12], after executing the power generation suppression operation and disabling hot water output, the process returns to [S11] again and the determination as to whether or not the second condition is satisfied is repeated. The subsequent flowchart is the same as FIG. 3. Note that "performing power generation suppressing operation" can also be read as "continuing power generation suppressing operation" as appropriate. Further, after hot water is tapped in [S9], the process returns to [S11] to determine whether or not the second condition is satisfied. Note that after the hot water is tapped in [S9], the process may return to [S1].

Note that if [S7] is [No], the process returns to [S3], but before returning to [S3], it may be determined again whether or not the second condition is satisfied. That is, the same determination as in [S11] may be added before returning to [S3]. Note that if the same judgment as this [S11] is added, if this judgment is [Yes], the power generation suppression operation has already been executed, so hot water is only disallowed, and the process returns to this judgment again. On the other hand, if the answer is [No], the process proceeds to [S3].

FIG. 7 is a flowchart of fuel cell high temperature suppression determination control for determining whether the second condition, which is a condition for suppressing power generation, is satisfied. This flowchart starts when the power supply to the external load that was once stopped in the self-sustaining mode is restarted, and is continuously executed (loop) during the self-sustaining operation.

When the control is started, first in [S31] it is determined whether the flag F2 is 0 (off). Flag F2 is a flag indicating whether or not the second condition is satisfied. When flag F2 is 0 (off), it indicates that the second condition is not satisfied, and when flag F2 is 1 (on), it indicates that the second condition is not satisfied. Indicates that the second condition is satisfied. Further, at the start of control, the flag F2 is 0 (off).

If the flag F2 is 0 (off) (Yes) in [S31], a determination is made to switch the flag F2 to 1 (on) in [S32] to [S33]. Further, if the flag F2 is 1 (on) [No] in [S31], a determination is made to switch the flag F2 to 0 (off) in [S35].

In [S31], if the flag F2 is 0 (off) [Yes], in [S32], the center temperature hTM1 of the fuel cell 11 measured by the first temperature measurement unit TM1 is equal to or higher than the first predetermined temperature H1. Determine whether or not. If hTM1 is greater than or equal to H1 [Yes], proceed to [S33]. If hTM1 is less than H1 (No), the fuel cell high temperature determination control ends with flag F2 being 0 (off).

Subsequently, in [S33], it is determined whether the air utilization rate Ua is equal to the lower limit value Uamin of the air utilization rate. If the air utilization rate Ua is equal to the lower limit value Uamin [Yes], the process proceeds to [S34], the flag F2 is switched to 1 (on), and the fuel cell high temperature suppression control is ended. If the air utilization rate Ua is not equal to the lower limit value Uamin [No], the fuel cell high temperature determination control is ended with the flag F2 being 0 (off).

Further, if the flag F2 is 1 (on) [No] in [S31], a determination is made to switch the flag F2 to 0 (off) in [S35]. If the center temperature hTM1 of the fuel cell 11 is less than the second predetermined temperature H2 (Yes), the process proceeds to [S36], the flag F2 is switched to 0 (off), and the fuel cell high temperature suppression control is ended. If the center temperature hTM1 of the fuel cell 11 is equal to or higher than the second predetermined temperature H2 [No], the fuel cell high temperature determination control ends with the flag F2 being 1 (on).

FIG. 8 is a flowchart showing a continuation determination control for determining whether to continue the hot water tapping operation, which starts when the hot water tapping operation starts and is continuously executed (in a loop) during the hot water tapping operation.

In [S41], it is determined whether power generation suppression (heat medium high temperature) has been resolved during hot water tapping operation. If the power generation suppression is resolved [Yes], the process advances to [S42] and the type of hot water tap request is determined. If the power generation suppression has not been resolved [No], the continuation determination control is ended.

In [S42], it is determined whether the hot water dispensing operation being executed is a hot water dispensing operation based on a user's hot water dispensing request or a forced hot water dispensing operation. If the hot water tapping operation is forced hot water taping [Yes], hot water taping is stopped in [S43] and the continuation determination control is ended. If the hot water dispensing operation is not a forced hot water dispensing operation but a hot water dispensing operation based on a user's hot water dispensing request [No], the hot water dispensing is not stopped and the continuation determination control is ended in [S44].

100 Fuel cell device 3 Heat storage tank 11 Fuel cell 30 Control device 60 Hot water tapping device

Claims (6)

A fuel cell that generates electricity,
a heat storage tank that stores a heat medium that has been heat exchanged with the exhaust heat of the fuel cell;
a control device that controls the operation of the fuel cell;
A hot water tapping device that taps hot water using the heat stored in the heat storage tank,
The control device is capable of executing a power generation suppressing operation in which power generation is performed at a lower output than the rated power when a power generation suppressing condition is satisfied during the self-sustaining operation, and when an operation instruction for the hot water tapping device is given during the self-sustaining operation. , comprising a hot water tap control that executes the operation of the hot water tap device,
The power generation suppression condition includes a second condition regarding the temperature of the fuel cell,
When the second condition is satisfied, the control device does not execute the hot water tapping control;
If the second condition is satisfied during execution of the hot water tapping control , the fuel cell device stops the hot water tapping control and executes the power generation suppression operation. 2. The fuel cell device according to claim 1, wherein the power generation suppression condition includes a first condition regarding the temperature of the heat medium stored in the heat storage tank. 3. The fuel cell device according to claim 2, wherein when the first condition is satisfied and the power generation suppressed operation is being executed, the control device cancels the power generation suppressed operation and executes the hot water output control. The fuel cell according to claim 3, wherein the control device determines whether the power generation suppression condition is satisfied after stopping the operation of the hot water tapping device, and executes the power generation suppression operation when the first condition is satisfied. Device. The control device determines whether to continue or stop the operation of the hot water tap device, depending on the type of operation instruction for the hot water tap device, when the power generation suppression condition is canceled during the operation of the hot water tap device. 4. The fuel cell device according to claim 3, wherein the fuel cell device executes continuation determination control. Any one of claims 2 to 5, wherein the control device notifies the user to select whether to operate a specific predetermined hot water tap device when the first condition is satisfied and to execute the hot water tap control. The fuel cell device described in .