JP6057819B2 - Fuel cell power generation system - Google Patents

Description

  The present invention relates to a fuel cell power generation system that controls a fuel cell that supplies power to a building.

  A solid oxide fuel cell (SOFC) has high power generation efficiency among fuel cells, but the operating temperature of the fuel cell needs to reach 700 to 1000 ° C. in order to generate power stably. Therefore, when the fuel cell is restarted after the fuel cell is stopped and the temperature is lowered, it takes time to reach a region where power generation with a stable operating temperature is possible.

  Due to the characteristics of SOFC, in ENE-FARM (registered trademark), which enables private power generation and hot water supply by SOFC, once the device is operated, the device will continue as long as the supply of city gas or LPG (liquefied petroleum gas) as fuel continues It is common to continue the operation.

  However, when a gas meter that controls the gas supplied to the building detects a continuous gas supply for a predetermined time or longer, the gas meter controls the gas supply to the building because there is a possibility of an abnormal situation such as a gas leak. . Since the SOFC operating at high temperature may cause a failure such as a failure of the apparatus when the gas supply is suddenly cut off, it is necessary to avoid interruption of the gas supply by the gas meter.

  For example, in the prior art described in Patent Document 1, a fuel buffer that stores in advance a gas that can operate the fuel cell for a predetermined time is provided, and the fuel valve of the fuel cell system is used to prevent the gas meter from stopping the gas supply. Cell for 2 seconds to change the gas flow rate to reset the gas leak detection of the gas meter and continue the operation of the fuel cell with the gas stored in the fuel buffer while the fuel valve is shut off A power generation system has been proposed.

JP 2010-170913 A

  However, the technique described in Patent Document 1 corresponds to the case where the gas meter stops supplying the gas when the gas supply continues for 10 hours and the flow rate does not vary by 3% or more. In the technology described in Patent Document 1, when the gas supply is stopped when the gas supply cannot be detected continuously for 30 days and the flow rate is not detected for one hour or more, a fuel cell is used with a timer. Is automatically stopped for one day, but gas consumption and power consumption in the time period for stopping are not considered. Therefore, the SOFC power generation is stopped during a time period when the electricity charge is high, and the amount of power purchased from the system power increases, which causes a problem that the electricity charge is increased for the user.

  The reason why the fuel cell as described above is automatically stopped for one day is that it is very unlikely that a gas device other than the fuel cell (such as a water heater or a gas stove) will be operated continuously for more than 24 hours. If it is stopped for one day (24 hours), the gas equipment will not be used during that time, and the gas supply can be in a state where there is no flow for one hour or more, and the gas leak detection of the gas meter can be reset. is there. The present invention has been made in consideration of the above-described facts, and an object of the present invention is to provide a fuel cell power generation system that avoids stopping of the fuel cell in a time zone when the electricity rate is high.

The invention of claim 1 for solving the above-described problems is a fuel cell installed in a building to which system power is supplied and using a combustible gas supplied to the building as fuel, and power consumed in the building And a detecting means for detecting gas, a storage means for accumulatively storing the power and gas consumption detected by the detecting means together with the date of consumption of the power and gas, and the fuel cell has started operation. In order to set the fuel cell stop time to the date and time when the electricity bill and gas bill within a predetermined period from the time are set low , if the setting of the electricity bill of the building is a metered lamp, the storage means is cumulative A time zone in which the electricity bill and the gas bill are the cheapest is extracted based on the consumption amount of electricity and gas and the date and time when the electricity and gas are consumed, and the fuel cell in the extracted time zone. Set the stop time When a predetermined time has elapsed from the stop time is set to return time operating the fuel cell together with the stopping of the fuel cell to stop time, and a control means for operating the fuel cell in the recovery time, Is provided.

According to the first aspect of the present invention, the control means cumulatively sets the time during which the fuel cell is stopped before the supply of gas is interrupted to a time zone when the electricity rate and the gas rate are low. The stop time of the fuel cell can be set in a time zone in which the electricity bill and gas bill extracted from the stored consumption amount of electricity and gas and the date of consumption of the electricity and gas are the lowest.

  According to a second aspect of the present invention, in the first aspect of the present invention, when the setting of the electricity charge of the building is a light by time zone in which the unit price of the electricity charge differs depending on the time zone, the control means The stop time is set in a time zone in which the unit price of the electricity bill is the lowest in the separate lamp.

  According to the second aspect of the present invention, the control means can set the stop time of the fuel cell in the time zone in which the unit price of the electricity bill is the lowest with the hourly lamp.

As described above, according to the first aspect of the present invention, the control means determines the time during which the fuel cell is stopped before the gas supply is interrupted , the cumulatively stored power, gas consumption, and power. In addition, by setting the electricity bill and gas bill extracted from the date and time when the gas was consumed to the lowest time zone, there is an effect of avoiding the stop of the fuel cell in the time zone when the electricity bill is high.

  According to the second aspect of the present invention, by setting the stop time of the fuel cell in the time zone in which the unit price of the electric charge is the lowest with the hourly electric lamp, the fuel cell is stopped in the time zone in which the electric charge is high. It has the effect of avoiding.

It is the schematic which shows an example of the fuel cell power generation system which concerns on embodiment of this invention. It is a block diagram which shows schematic structure of HEMS in the fuel cell power generation system which concerns on embodiment of this invention. It is a flowchart which shows an example of the process of HEMS in the fuel cell power generation system which concerns on embodiment of this invention. It is a figure which shows an example of a display of the next scheduled automatic stop date in the fuel cell power generation system which concerns on embodiment of this invention. It is a figure which shows an example of the display which inputs the scheduled stop date in the fuel cell power generation system which concerns on embodiment of this invention. It is a figure which shows an example of the lamp according to time slot | zone in embodiment of this invention. It is a flowchart which shows an example of the process which extracts the time slot | zone with the least total of the electricity bill and the gas bill in the fuel cell power generation system which concerns on embodiment of this invention. In the fuel cell power generation system concerning an embodiment of the invention, it is an example of the graph which plotted the amount of money on the horizontal axis, and the number of cases on the vertical axis about the electricity bill and gas bill of the same time slot in a predetermined period.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an example of a fuel cell power generation system according to an embodiment of the present invention.

  In the present embodiment, power from the grid power 12 is supplied to the distribution board 14 of the building 10 through the main breaker 100. The building 10 is, for example, a commercial facility such as a retail store including a convenience store or a house.

  On the system power side of the main breaker 100, a main breaker current sensor 120 that detects the current value of the power supplied from the system power 12 is provided.

  In addition, the power generated by the SOFC 70 is supplied to the distribution board 14 via the fuel cell breaker 104. The current value of the electric power supplied from the SOFC 70 to the distribution board 14 can be detected by the fuel cell current sensor 124.

  The SOFC 70 is provided with conversion means (not shown) such as an inverter that can convert the direct current generated by the SOFC 70 into alternating current (for example, 100 V, 50 Hz) supplied from the distribution board 14 to the home appliance 34.

  The SOFC 70 is supplied with combustible gas as fuel. In addition, when the SOFC 70 is ENE-FARM (registered trademark) that heats tap water with the waste heat of power generation, tap water is also supplied. The supplied tap water is heated by the heat generated when the SOFC 70 is operated and stored in the hot water storage tank 72. The gas is also supplied to a gas appliance 78 such as a cooking appliance, and the HEMS 30 can also control the gas appliance 78.

  The power supplied from the grid power 12 and the SOFC 70 to the distribution board 14 is supplied via the branch circuits 20C and 20B to the housing equipment 32 and the home appliance 34 that are power load means. The branch circuit 20A is for supplying power for starting the SOFC 70.

  The branch circuits 20A to 20C are provided with current sensors 22A to 22C for measuring the current values of the branch circuits 20A to 20C, respectively. The information lines from the current sensors 22A to 22C are connected to the HEMS 30 together with the information lines from the main breaker current sensor 120 and the fuel cell current sensor 124 and the information lines for the HEMS 30 to control the distribution board 14.

  In FIG. 1, the broken line is an information line through which measurement data or control information flows.

  The branch circuits 20A to 20C of the distribution board 14 are respectively provided with branch breakers 24A to 24C for switching the branch circuits 20A to 20C to an on state or an off state, and the branch breakers 24A to 24C are controlled by the HEMS 30. .

  In FIG. 1, only three systems of branch circuits are shown for simplification of description, but in this embodiment, three or more systems or three systems or less may be used, and the number of branch circuits is not particularly limited. .

  The HEMS 30 is connected to a gas meter 132 that measures the flow rate of the gas supplied to the SOFC 70 and the like and a water meter 130 that measures the flow rate of the water supply, and can acquire information on the gas flow rate and the water supply flow rate. Further, an electromagnetic valve 134 that can be opened and closed by a command from the gas meter 132 is provided in the gas supply path downstream from the gas meter 132. The gas meter 132 controls the electromagnetic valve 134 to interrupt the supply of the gas to the SOFC 70 and the gas appliance 78 when the gas has been used for a long time.

  FIG. 2 is a block diagram showing a schematic configuration of the HEMS 30 according to the fuel cell power generation system according to the present embodiment.

  As shown in FIG. 2, the HEMS 30 includes a CPU 36, a ROM 38, a RAM 40, and an input / output port 42. These include a bus 44 such as an address bus, a data bus, and a control bus. Are connected to each other.

  A display unit 46, an operation unit 48, and a memory 50 are connected to the input / output port 42 as various input / output devices. The display unit 46 and the operation unit 48 are integrally configured, and a touch panel provided on the display unit 46 can be applied to the operation unit 48.

  The display unit 46 can display the amount of power consumed by the power load means such as the home appliance 34, the amount of tap water detected by the water meter 130, the amount of gas detected by the gas meter 132, the amount of power generated by the SOFC 70, and the like. is there.

  The power consumption of the home appliance 34 can be calculated from the current value detected by the current sensor 22B, and the power consumption of the residential equipment 32 can be calculated from the current value detected by the current sensor 22C. Further, the power generation amount of the SOFC 70 can be calculated based on the current value detected by the fuel cell current sensor 124.

  Since the voltage of the power supplied from the distribution board 14 to the power load means and the power supplied from the SOFC 70 is approximately 100 V, in this embodiment, the current value detected by each current sensor is multiplied by 100 to obtain the amount of power. Can be calculated. However, in a branch circuit with a large voltage fluctuation, a means for measuring the voltage may be provided separately.

  The memory 50 stores a program for controlling the branch breakers 24A to 24C, a program for controlling the SOFC 70, and various information for executing these programs.

  The HEMS 30 performs various types of control such as control of power supplied to the building 10 by developing a program stored in the memory 50 in the RAM 40 and executing it by the CPU 36.

  Further, the distribution board 14, the SOFC 70, the gas appliance 78, the water meter 130 and the gas meter 132 are connected to the input / output port 42.

  In the present embodiment, the HEMS 30 may cumulatively store in the memory 50 not only the electric power but also the water flow rate and the gas flow rate detected by the water meter 130 and the gas meter 132 in association with the detected date. Is possible.

  Subsequently, control of the HEMS 30 according to the present embodiment will be described. FIG. 3 is a flowchart showing an example of HEMS processing in the fuel cell power generation system according to the present embodiment.

  In step 300, the scheduled date when the SOFC 70 automatically stops next is displayed on the display unit 46 of the HEMS 30. FIG. 4 is a diagram illustrating an example of a display of the next scheduled automatic stop date in the fuel cell power generation system according to the present embodiment. In the present embodiment, when the gas meter 132 senses that the gas is continuously supplied for 30 days or more, the gas supply is stopped for at least one hour. Stop automatically. When the predetermined time has elapsed after stopping, the SOFC 70 is automatically returned (restarted).

  If the gas meter 132 detects that the gas has been continuously supplied for 30 days or more during the predetermined period from the automatic return to the next automatic stop, the SOFC 70 automatically returns, etc. Within 30 days from the start of operation. In this embodiment, it is 26 days as an example. In addition, when the gas meter 132 stops supply of gas in a period different from 30 days, the predetermined period may be changed as appropriate.

  In step 302, it is determined whether or not the user has selected “Yes” or “No” within a predetermined time in the display shown in FIG. 4, and in the case of an affirmative determination, “Yes” in FIG. It is determined whether or not is selected. The predetermined time can be arbitrarily set, but is set to about 10 to 30 minutes as an example.

  If the determination in step 304 is affirmative, the SOFC is stopped on the scheduled date displayed in step 306 and automatically returned in step 314.

  If a negative determination is made in step 304, a screen for designating a scheduled stop date is displayed in step 308. FIG. 5 is a diagram showing an example of a display for inputting a scheduled stop date in the fuel cell power generation system according to the present embodiment. Note that the scheduled stop date can be set not only for the year / month / day but also for the minute / second.

  In step 310, it is determined whether or not the scheduled stop date is set within a predetermined time. If the determination is affirmative, the SOFC 70 is stopped on the scheduled date displayed in step 312 and automatically returned in step 314. Note that the predetermined time in step 310 can be set arbitrarily, but as an example, it is about 10 to 30 minutes.

  If a negative determination is made in step 302 and a negative determination is made in step 310, it is determined in step 316 whether or not the electricity bill of the building 10 is a time-specific lamp whose unit price of the electricity bill differs depending on the time zone. FIG. 6 is a diagram showing an example of a time-specific lamp according to the embodiment of the present invention. In FIG. 6, the electricity charges are set to be low at night and high during the day.

  If the determination in step 316 is affirmative, in step 318, a time zone in which the electricity rate is low is set as the stop time of the SOFC 70, and the SOFC 70 is stopped at the stop time, and is automatically returned in step 314.

  If a negative determination is made in step 316, that is, if the electricity rate is set to a metered lamp, the SOFC 70 is stopped in a time zone in which the total of the electricity bill and gas bill calculated from the past use history in step 320 is the smallest, step 314 To restore automatically. In the present embodiment, the SOFC 70 is stopped in a time zone in which the sum of the electricity bill and the gas bill is the cheapest. However, the SOFC 70 may be stopped in a time zone in which either the electricity bill or the gas bill is the cheapest. .

  The time for stopping the SOFC 70 in steps 306, 318, and 320 is 1 hour in the present embodiment, although it depends on the specifications of the gas meter 132. Further, the time until the operation is started after the SOFC 70 is stopped is set to 10 to 24 hours. Depending on the specifications of the SOFC 70, there is a case where the temperature of the device is returned to room temperature and then the temperature of the device is gradually raised to operate. In such a case, the SOFC 70 is restarted after 10 hours from 24 hours until it is restarted. It takes time. The HEMS 30 sets the return time for automatically returning the SOFC 70 when the time required for the SOFC 70 to restart from the set stop time, and automatically returns the SOFC 70 at the return time.

  FIG. 7 is a flowchart showing an example of processing for extracting a time zone in which the sum of the electricity bill and the gas bill is the smallest in the fuel cell power generation system according to the present embodiment. In this embodiment, since the SOFC 70 is stopped in the time zone in which the total of the electricity bill and the gas bill is the smallest in Step 320 of FIG. 3, the sum of the electricity bill and the gas bill is calculated from the past electricity and gas usage history. Processing to extract the least time zone is required.

  First, in step 700, the electricity and gas usage history in a predetermined period is stored in the memory 50 cumulatively together with the date and time of use of electricity and gas consumption. The predetermined period may be a period during which the tendency of consumption of electricity and gas in the building 10 can be grasped. For example, the predetermined period may be three months, one month, or one week. The electricity consumption is calculated from the amount of power based on the detection results by the current sensors 22A to 22C, and the gas consumption is based on the result detected by the gas meter 132.

  Step 702 calculates an electricity bill and a gas bill for each time period from the usage history stored in the memory 50 for a predetermined period. The electricity bill and gas bill are calculated by multiplying the consumption by the unit price. The time zone may be each time zone when one day is divided in units of three hours, or each time zone when one day is divided in units of two hours. Each time zone when is divided in units of one hour. Note that the unit price of the electricity charge and the unit price of the gas charge are stored in the memory 50 in advance.

  In step 704, an electricity bill and a gas bill for the same time period in a predetermined period are extracted as samples. In the sample extraction, an electricity bill and a gas bill are extracted for each time zone that is the same time zone in a predetermined period. In addition, sample extraction is performed for all the time zones that divide the day.

  In step 706, in each sample extracted for the same time period in a predetermined period, the electricity bill and the gas bill are added together, and digits less than the predetermined amount are rounded off. For example, when the time zone is one hour, the predetermined amount may be 10 yen.

  In step 708, each sample obtained by adding the electricity bill and gas bill in step 706 is plotted on a graph in which the horizontal axis indicates the amount of money and the vertical axis indicates the number of samples. FIG. 8 is an example of a graph plotting the amount of money on the horizontal axis and the number of samples on the vertical axis for the electricity and gas charges in the same time period in a predetermined period in the fuel cell power generation system according to the present embodiment. In general, if the number of samples is sufficiently large, the graph draws a convex curve centered on the mode as shown in FIG. Note that the processing in steps 706 and 708 is performed for all the time zones dividing one day.

  In step 710, a sample in a predetermined range centering on the mode value on the graph is extracted. This is a process for excluding samples that deviate significantly from the mode value. As an example, the predetermined range may be 70% centered on the mode value.

  In step 712, the amount of each sample extracted in step 710 is summed to calculate a total amount centered on the mode value in each time zone. In step 714, the calculated total amount is compared, and the amount is low. Each time zone is ranked from the order, and the process is terminated.

  With the above processing, it is possible to determine a time zone in which the total of the electricity bill and the gas bill is the smallest. In the present embodiment, samples that deviate significantly from the mode value are excluded by extracting a sample in a predetermined range centered on the mode value in step 710 without distinguishing between weekdays and holidays. Although the calculation is complicated, the electricity bill and gas bill for each time zone are divided into weekdays and holidays, and samples centered on the mode are each extracted within a predetermined range, and the sum of electricity bill and gas bill is the most. Decide on a small time zone for weekdays and holidays. Furthermore, the time zone with the least electricity bill and gas bill is determined from the amount of money with the least electricity bill and gas bill on weekdays and the amount of money with the least electricity bill and gas bill on holidays. In step 320, the SOFC 70 may be stopped at the determined time zone.

  As described above, according to this embodiment, the SOFC 70 is automatically stopped at the time when the electricity bill and the gas bill are the lowest, thereby avoiding the stoppage of the fuel cell at the time when the electricity bill is high. can do.

DESCRIPTION OF SYMBOLS 10 Building 12 System electric power 14 Distribution board 22A, 22B, 22C Current sensor 32 Housing equipment 34 Home appliance 36 CPU
38 ROM
40 RAM
46 Display unit 48 Operation unit 50 Memory 70 SOFC
132 gas meter

Claims (2)

A fuel cell installed in a building to which system power is supplied and fueled with a combustible gas supplied to the building;
Detection means for detecting power and gas consumed in the building;
Storage means for cumulatively storing the consumption of power and gas detected by the detection means together with the date and time when the power and gas were consumed;
In the case where the electricity rate of the building is a metered lamp in order to set the fuel cell stop time to the date and time when the electricity bill and gas bill become cheap within a predetermined period from when the fuel cell starts operation Extracts the time zone in which the electricity and gas costs are the lowest based on the consumption of electricity and gas stored in the storage means and the date and time when the electricity and gas are consumed. Set a stop time of the fuel cell in the time zone and set a return time for operating the fuel cell when a predetermined time has elapsed from the stop time, stop the fuel cell at the stop time, Control means for operating the fuel cell at a return time;
Fuel cell power generation system equipped with.   In the case where the setting of the electricity charge of the building is a light by time zone in which the unit price of the electricity charge differs depending on the time zone, the control means is configured to perform the operation in the time zone in which the unit price of the electricity rate is the lowest. The fuel cell power generation system according to claim 1, wherein a stop time is set.

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