JP2021068543A - Fuel cell system - Google Patents

Abstract

To provide a fuel cell system that can prevent a reduction in merit of operating a fuel cell.SOLUTION: A fuel cell system 100 of the present disclosure comprises: a fuel cell 11 that generates electric power supplied to a user; and a control unit 30 that controls the operation of the fuel cell 11. The control unit 30 includes: a calculation unit 31 that calculates a demanded power amount that is demanded by the user; a demanded power arithmetic unit 32 that calculates the average demanded power amount that is the average value of the demanded power amounts in a first period; and an operation determination unit 33 that determines whether the fuel cell 11 can be operated. The demanded power arithmetic unit 32 calculates the average demanded power amount by using a period, of the first period, during which the fuel cell 11 is continuously operated until the calculation of the average demanded power amount. The operation determination unit 33 executes first determination of comparing the average demanded power amount with a preset determination value and determining whether the fuel cell 11 can be operated.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a fuel cell system.

A solid oxide fuel cell that generates electricity using air and fuel gas generated by steam reforming raw fuel gas is known. When the power consumption of the fuel cell is small for the consumer, it may be more advantageous to stop the operation of the fuel cell than to operate the fuel cell from the viewpoint of running cost and the like.

For example, Patent Document 1 has an advantage by determining whether to continue or stop the operation of a fuel cell based on an alternative value derived from an average calculated value of load measurement values measured over a predetermined period and a determination threshold value. It discloses a fuel cell system that suppresses the decrease in fuel cell.

Japanese Unexamined Patent Publication No. 2017-174750

In the conventional fuel cell system, the alternative value does not reflect the actual power consumption of the consumer, and it may not be possible to accurately determine whether to continue or stop the operation of the fuel cell.

The fuel cell system of the present disclosure includes a fuel cell that generates electric power to be supplied to a consumer, and a control unit that controls the operation of the fuel cell. The control unit includes a calculation unit that calculates the required power amount required by the consumer, a required power calculation unit that calculates an average required power amount that is an average value of the required power amount in the first period, and the above. It is provided with an operation determination unit for determining whether or not the fuel cell can be operated. The required power calculation unit calculates the average required power amount by using the period during which the fuel cell is continuously operated until the time when the average required power amount is calculated. The operation determination unit performs a first determination to determine whether or not the fuel cell can be operated by comparing the average required electric energy with a preset determination value.

According to the fuel cell system of the present disclosure, it is possible to accurately determine whether to continue or stop the operation of the fuel cell based on the actual power consumption of the consumer.

It is a figure which shows the schematic structure of the fuel cell system which concerns on embodiment. It is a flowchart explaining the merit reduction suppression control. It is a flowchart explaining the merit reduction suppression control.

Hereinafter, the fuel cell system according to the embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a fuel cell system according to an embodiment.

The fuel cell system 100 of the embodiment includes a fuel cell 11 that generates electricity using a fuel gas and an oxygen-containing gas. The fuel cell 11 may have a cell stack structure including a plurality of fuel cell cells. The fuel cell may be a solid oxide fuel cell.

The fuel cell system 100 includes a reformer 12 that produces a fuel gas to be supplied to the fuel cell 11. The reformer 12 reforms raw fuel gas such as natural gas and LP gas to generate fuel gas.

The fuel cell system 100 includes a module 1 including a fuel cell 11 and a reformer 12 housed in a storage container 10. Further, the fuel cell system 100 includes a first heat exchanger 2 that exchanges heat between the exhaust heat of the module 1 and the heat medium, and a heat storage tank 3 that stores the heat medium. The exhaust gas (exhaust heat) discharged from the module 1 exchanges heat with the heat medium flowing in the first heat exchanger 2 in the first heat exchanger 2. At this time, the water contained in the exhaust gas condenses to generate condensed water. The generated condensed water is supplied to the reformer 12 via the condensed water flow path C, and is used as the reforming water in the steam reforming reaction in the reformer 12. The condensed water flow path C may be provided with a reformed water tank for storing condensed water. The exhaust gas from which the water has been removed is exhausted to the outside through the exhaust gas flow path E.

The fuel cell system 100 includes a first circulation path HC. The first circulation path HC is a path through which the heat medium circulates between the heat storage tank 3 and the first heat exchanger 2. The first circulation path HC has a pipe that connects the heat storage tank 3 and the first heat exchanger 2 and allows the heat medium to flow through. The first circulation path HC may be provided with a circulation pump for circulating the heat medium and a radiator for cooling the heat medium.

The fuel cell system 100 may include a second circulation path and a second heat exchanger provided in the second circulation path. The second circulation path is connected to the heat storage tank 3 and may not be connected to the first circulation path HC. For example, the second circulation path is a path through which the heat medium circulates, has a pipe through which the heat medium flows, and heats water such as tap water supplied from the outside with a second heat exchanger to heat the water. It may be configured to deliver warm water to the outside. The fuel cell system 100 may be a so-called monogeneration system that does not supply hot water to the outside.

The fuel cell system 100 further includes a water supply flow path W for supplying a heat medium to the heat storage tank 3. The water supply flow path W includes a pipe connecting a water supply source that supplies a heat medium from the outside and a heat storage tank 3. When the fuel cell system 100 is started, the heat medium is supplied from the water supply source to the heat storage tank 3 via the water supply flow path W. The water supply source is, for example, water supply, and the heat medium supplied from the water supply source is tap water.

The fuel cell system 100 performs a power generation operation of the fuel cell 11 including an oxygen-containing gas supply device 14 that supplies oxygen-containing gas to the fuel cell 11, a raw fuel gas supply device 15 that supplies raw fuel gas to the reformer, and the like. Equipped with auxiliary equipment to assist.

The fuel cell system 100 further includes a power conditioner 20, a control unit 30, a remote controller 40, and the like as auxiliary machines for assisting the power generation operation of the fuel cell 11.

The power conditioner 20 has an inverter 21 that converts the DC power generated by the fuel cell 11 into AC power and outputs it. The output of the inverter 21 is connected to the breaker 51 provided in the distribution board 50 installed in the customer. A current sensor (not shown) is attached to the breaker 51.

The control unit 30 includes at least one processor, a storage device, and the like, and provides control and processing power for performing various functions, as described in detail below.

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

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

According to various embodiments, the processor is one or more processors, controllers, microprocessors, microcontrollers, application-specific integrated circuits, digital signal processors, programmable logic devices, field programmable gate arrays, or devices thereof or Any combination of configurations, or other known device and configuration combinations, may be included to perform the functions described below.

The control unit 30 is connected to a storage device and a display device (both not shown), various components and various sensors constituting the fuel cell system 100, and includes each of these functional units and the entire fuel cell system 100. Control and manage. The control unit 30 acquires a program stored in a storage device attached to the control unit 30 and executes this program to realize various functions related to each part of the fuel cell system 100.

When the control unit 30 transmits a control signal or various kinds of information to another function unit or device, the control unit 30 and the other function unit may be connected by wire or wirelessly. The control characteristic of the embodiment performed by the control unit 30 will be described later. In the embodiment, the control unit 30 controls various auxiliary machines based on the instructions and commands of the external device connected to the fuel cell, and the instructions and measured values of the various sensors described above. In the figure, the connection line connecting the control unit 30, each device constituting the fuel cell, and each sensor 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 the processing result. The storage device includes a recording medium. The recording medium may include any non-transitory storage medium such as a semiconductor storage medium and a magnetic storage medium. Further, the storage device may include a plurality of 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).

The control unit 30 and the storage device of the fuel cell system 100 can also be realized as a configuration provided outside the fuel cell system 100. Further, it can be realized as a control method including a characteristic control step in the control unit 30 according to the present disclosure, or as a control program for causing a computer to execute the above steps.

The remote controller 40 is provided in the customer's house and has a display device and an operation panel. By operating the remote controller 40, the consumer can transmit various instructions relating to the operation of the fuel cell 11 to the control unit 30. Further, the consumer can change the date and time setting of the fuel cell system 100 by operating the remote controller 40.

Hereinafter, the merit reduction suppression control executed by the control unit 30 in the fuel cell system 100 will be described.

The control unit 30 has a calculation unit 31, a required power calculation unit 32, and an operation determination unit 33, and determines the operating merit of the fuel cell system 100 based on the power consumption of the consumer (hereinafter, the required power amount). ..

The required power amount is the sum of the power purchase amount Q from the power company and the power generation amount R of the fuel cell 11. The calculation unit 31 can calculate the power purchase amount Q from the electric power company, for example, based on the measured value of the current sensor attached to the breaker 51 of the distribution board 50. Further, the calculation unit 31 can calculate the power generation amount R of the fuel cell 11 based on the output of the inverter 21 mounted on the power conditioner 20, for example. If the consumer is equipped with a power generation device other than the fuel cell 11, the amount of power generated by the power generation device may be taken into consideration.

The control unit 30 determines the operating merit of the fuel cell system 100 based on the required electric energy of the first period T1 set in advance. The first period T1 may be a period represented by the number of days, for example, the number of days in one month. Further, the control unit 30 acquires the current date and time information at the start of this control, and sets a determination date for determining the driving merit based on the date and time information and the first period T1. The determination date may be set as a due date, for example, at the end of the month, and in this case, the period from the start of this control to the determination date may be set as the first period T1. That is, the first period T1 changes depending on the setting of the start date and the determination date of this control. However, in this case, the determination date may be set in advance so that the first period T1 is longer than the second period T2.

Here, the second period T2 is, for example, a period of 1 to 5 days. When the fuel cell 11 is continuously operated for a short period of time, it may be difficult to calculate the amount of electric power that reflects the actual amount of electric power consumed by the consumer. Therefore, by setting the determination date in advance so that the first period T1 is longer than the second period T2, the determination can be made using the electric energy that reflects the actual power consumption of the consumer. As a result, the convenience of consumers can be improved.

The calculation unit 31 calculates the first required electric energy P1 for each preset calculation cycle U1. The calculation cycle U1 can be set as appropriate, and is, for example, 0.1 to 60 seconds. Further, the demand power calculation unit 32 calculates the second demand power amount P2 by integrating the first demand power amount P1 calculated for each calculation cycle U1 over the preset integration cycle U2. The integration cycle U2 is set to a period longer than the calculation cycle U1 and shorter than the first period T1. The integration cycle U2 can be appropriately set, and may be, for example, 24 hours, 12 hours, or 8 hours.

In the first period T1, the required power calculation unit 32 integrates the integration cycle U2 for which the second required power amount P2 is calculated to calculate the integration calculation period UA. When the second required electric energy P2 is integrated over the first period T1, the integrated calculation period UA is the same number of days as the first period T1.

The control unit 30 determines the continuous operation of the fuel cell system 100 based on the continuous operation flag. The continuous operation flag is turned off when the operation of the fuel cell system 100 over time cannot be confirmed, for example, when the breaker 51 is switched from ON to OFF, or when the date and time setting of the remote controller 40 is changed. In this control, it is assumed that the operation is performed even when the breaker 51 is turned on but the power is not generated, that is, in the so-called standby state. When the continuous operation flag is turned off, the demand power calculation unit 32 considers the possibility that the integrated values of the first demand power amount P1 and the second demand power amount P2 in the first period T1 may be missing, and the first 1 The integrated required power amount P1 and the second required electric energy P2 and the integrated calculation period UA are reset.

When the date and time when the breaker 51 is returned from OFF to ON or the date and time reset by the remote controller 40 is a date and time before the date and time when this control is started, or a date and time after the determination date. In some cases, the judgment date is reset because accurate merit judgment cannot be performed.

Required power calculating section 32 calculates the sum and a required power amount accumulated value P _I of the second power requirements P2 integration calculation period UA in the first period T1. Further, the required power calculating section 32, by dividing the required power amount accumulated value P _I in days integration calculation period UA, calculates the average power requirements P _AVG. The average required electric energy _PAVG is the average value of the required electric energy per day in the first period T1. Required power amount accumulated value P _I and the average power requirements P _AVG calculation, of the integration cycle U2 included in the first period T1, may be performed at the end of the integration cycle U2.

The required power calculation unit 32 adds and divides the second required power amount P2 calculated for each integration cycle U2 in the first period T1, so that the average required power amount P for each integration cycle U2 elapses. _{The average required electric energy P AVG} in the first period T1 may be calculated by calculating the _AVG and executing the calculation of the average required electric energy P AVG until the final integration cycle U2.

In the fuel cell system 100, the required power calculation unit 32 receives the required power integrated value P in the integrated calculation period UA in _{which the fuel cell 11 is continuously operated until the calculation of the average required electric energy P AVG in the first period T1.} using _I, it calculates the average power requirements _{P AVG. As a result, in the first period T1, the average required power amount PAVG} is calculated excluding the integration period in which the second required power amount P2 may be missing because continuous operation has not been confirmed. The electric energy _PAVG can reflect the actual electric energy consumption of the consumer. As a result, it is possible to accurately determine whether or not there is a merit in continuing the power generation operation of the fuel cell 11.

Operation determination unit 33 compares the average power requirements P _AVG and preset determination value P _C, performing the first determination determining whether the operation of the fuel cell 11. Operation determination unit 33 determines if the average power requirements P _AVG is preset determination value less than P _C, and better to stop operation of the fuel cell 11 is advantageous. Operation determination unit 33 determines if the average power requirements P _AVG is the determination value P _C or more, and better to continue the operation of the fuel cell 11 is advantageous.

Although the determination value P _C in the fuel cell system 100 is set in advance, customer can operate the remote controller 40, to change the decision value P _C to an arbitrary value. Decision value P _C is the power rate of the system power source, the raw material costs to become gas rates for operation of the fuel cell 11, based on the water charge, etc., and charges per unit electric power in the fuel cell 11, per unit electric power of the system power source It is set by comparing with the electricity rate. If various preferential treatments are received, the electricity rate per unit power of the grid power source may be set in consideration of the preferential treatment.

Further, the consumer can operate the remote controller 40 to set so that the operation determination unit 33 does not execute the first determination. The setting that does not execute the first determination means that the average required electric energy P _AVG is not compared with the determination value P _C , and that this control is not executed and the average required electric energy P _AVG is not calculated. Including.

When the determination date is set in a period shorter than the second period T2 in the determination date setting, in other words, the integrated calculation which is the calculation period of the _{average required electric energy PAVG calculated by the required power calculation unit 32.} When the period UA is shorter than the second period T2 set shorter than the first period T1, the operation determination unit 33 may be configured not to execute the first determination.

The control unit 30 may start or stop the fuel cell 11 based on the result of the first determination after the third period T3 after executing the first determination has elapsed. As a result, the control unit 30 can receive an instruction from the consumer to continue or stop the operation of the fuel cell 11 within the third period T3 after executing the first determination. As a result, the convenience of consumers can be improved. In the case of the determination to operate the fuel cell 11 in the first determination, the operation may be started immediately after the determination without waiting for the elapse of the third period T3.

When the result of the first determination is the determination result of stopping the operation of the fuel cell 11, the control unit 30 may display the determination result on the remote controller 40. By notifying the consumer of the determination result of the first determination before stopping the operation of the fuel cell 11 based on the result of the first determination, the convenience of the consumer can be improved. The determination result may also be displayed when the fuel cell 11 is operated.

Further, when the instruction from the remote controller 40 by the consumer is received, the control unit 30 may preferentially execute the instruction by the consumer regardless of the determination result of the first determination. As a result, the convenience of the consumer can be improved.

When the operation of the fuel cell 11 is stopped based on the result of the first determination, the control unit 30 gives an instruction by the consumer when the instruction to start the operation of the fuel cell 11 by the consumer is received by the remote controller 40. May be prioritized and the operation of the fuel cell 11 may be started. As a result, the convenience of the consumer can be improved.

Hereinafter, the merit reduction suppression control executed by the control unit 30 will be described with reference to the flowchart. 2 and 3 are flowcharts for explaining the merit reduction suppression control. In the flowchart, "step" is abbreviated as "S", and in the chart, "positive" (computer flag = 1) in judgment control is [Yes], and "no" (computer flag = 0 zero) is [ No]. The flowchart starts at a preset date and time. In the following, it will be explained that the control starts at the beginning of the month.

The control unit 30 acquires the current date and time information in [S21], and further sets a determination date for performing the merit determination in [S22] based on the acquired date and time information and the preset first period T1. .. As for the setting of the determination date, as described above, the first period T1 is set to be longer than the second period T2.

Next, in [S23], it is determined whether or not the continuous operation flag is ON. When the continuous operation flag is OFF [No], it will be described later. If the continuous operation flag is ON [Yes], the process proceeds to the determination of [S24].

In [S24], it is determined whether or not the calculation cycle U1 has elapsed. If [No] does not pass the calculation cycle U1, the process returns to [S23]. In the case of [Yes] after the calculation cycle U1, the first required electric energy P1 is calculated in [S25], and the calculated first required electric energy P1 is further integrated in [S26]. If [No] does not pass the calculation cycle U1, [S24] may be repeated.

Next, in [S27], it is determined whether or not the integration cycle U2 has elapsed. If [No] does not pass the integration cycle U2, the process returns to [S23]. In the case of [Yes] after the integration cycle U2 has elapsed, the second required electric energy P2 is calculated in [S28], and the calculated second required electric energy P2 is integrated in [S29]. Further, in [S30], the integration calculation period UA is integrated.

Next, in [S31], it is determined whether or not the determination date has been reached. If it is not the determination date [No], the process returns to [S23]. If it is the determination date [Yes], the process proceeds to [S41] in FIG. 3 to evaluate the merit.

Here, in [S23], when the continuous operation flag is OFF [No], there is a possibility that the integration of the required electric energy is missing. Therefore, the process proceeds to [S33] and the integration of the first required electric energy P1 is performed. Reset. Further, in [S34], the integration of the second required electric energy P2 is reset, and in [S35], the integration of the integration calculation period UA is reset.

Next, in [S36], it is determined whether or not it is necessary to reset the determination date. If it is necessary to reset the determination date [Yes], the process returns to [S21], the current date and time is acquired again, and the determination date is reset. If it is not necessary to reset the determination date [No], the process returns to [S23] and the integration of the required power is started again.

Required power calculating section 32 calculates the required power amount accumulated value P _I in [S41], in [S42], by dividing the required power amount accumulated value P _I in days integration calculation period UA, average power requirements P _AVG is calculated, and the process proceeds to [S43].

Operation determination unit 33, in [S43], determines the determination value _{P C} is whether the average request power _P or _AVG greater. Decision value _{P C} is greater than the average required power _{P AVG} [Yes] If, in [S44], the benefits determined and stop priority, the process proceeds to [S45]. The merit determination represents a determination result in which at least the operation of the fuel cell 11 is stopped. The determination result may be expressed even when it is advantageous to continue the operation of the fuel cell 11. When the merit determination gives priority to stop, it indicates a determination result that it is more advantageous to stop the operation of the fuel cell 11. Further, when the merit determination is prioritized for operation, the determination result that it is more advantageous to continue the operation of the fuel cell 11 may be expressed. For the determination value _{P C} is the average required power _{P AVG} following [No], in [S49], and the power generation priority benefit determination.

Next, in [S45], the determination result of the merit determination is displayed on the remote controller 40, and the process proceeds to the determination in [S46].

In [S46], it is determined whether or not there is an instruction from the consumer to execute the power generation of the fuel cell 11. When the consumer is notified of the merit determination, the remote controller 40 can give an instruction regarding the operation of the fuel cell 11. If there is no instruction from the consumer to execute the power generation of the fuel cell 11 [Yes], the process proceeds to the determination of [S47].

In [S47], it is determined whether or not the third period T3 has elapsed. In the case of [Yes] after the third period T3 has passed, in [S48], if the fuel cell system 100 is operating, the operation is stopped, and if the operation is already stopped, the operation is continued and the flowchart is continued. To finish. If [No] has not passed the third period T3, the process returns to [S46].

When there is an instruction in [S46] to execute power generation of the fuel cell 11 by the consumer, the merit determination is prioritized in [S49] as in the case where [S43] is [No].

Next, in [S50], it is determined whether or not the third period T3 has elapsed. When the third period T3 has elapsed [Yes], in [S51], if the fuel cell system 100 is operating, the operation is continued, and if the operation is stopped, the operation is started and the flowchart is terminated. If [No] has not passed the third period T3, the process returns to [S46]. In addition, when the power generation of the fuel cell 11 is executed, [S50] may be omitted.

11 Fuel cell 30 Control unit 31 Calculation unit 32 Required power calculation unit 33 Operation judgment unit 100 Fuel cell system

Claims (6)

Fuel cells that generate electricity to supply customers and
A control unit that controls the operation of the fuel cell is provided.
The control unit
A calculation unit that calculates the required electric energy required by the consumer,
The required power calculation unit that calculates the average required power amount, which is the average value of the required power amount in the first period,
It is provided with an operation determination unit for determining whether or not the fuel cell can be operated.
The required power calculation unit calculates the average required power amount by using the period during which the fuel cell is continuously operated until the calculation of the average required power amount in the first period.
The operation determination unit executes a first determination to determine whether or not the fuel cell can be operated by comparing the average required electric energy with a preset determination value.
Fuel cell system. The operation determination unit executes the first determination when the calculation period of the average required power amount calculated by the required power calculation unit is shorter than the second period set shorter than the first period. No, the fuel cell system according to claim 1. The fuel cell system according to claim 1, wherein the control unit executes operation or stop of the fuel cell based on the result of the first determination after the lapse of a third period after the execution of the first determination. It is equipped with a remote controller that receives instructions regarding the operation of the fuel cell from the customer, and also has a remote controller.
The fuel cell system according to claim 1 or 3, wherein the control unit displays the determination result on the remote controller when the first determination is a determination result of stopping the operation of the fuel cell. The fuel cell system according to claim 4, wherein the control unit preferentially executes an instruction by the consumer when an instruction by the consumer is received by the remote controller. It is equipped with a remote controller that receives instructions regarding the operation of the fuel cell from the customer, and also has a remote controller.
When the operation of the fuel cell is stopped according to the result of the first determination,
The control unit
The fuel cell system according to claim 1, wherein when the customer's instruction to start operation of the fuel cell is received by the remote controller, the operation of the fuel cell is started with priority given to the instruction by the customer.

Images