JP2012207829A - Cogeneration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cogeneration system that can secure a desired heat storage amount without increasing a size of, for example, a hot water storage unit.SOLUTION: In a fuel cell system 1, an electric heater 9 is controlled on the basis of an estimated value of the heat storage amount in the hot water storage unit 3 by an operation control device 20. Thus, a temperature of hot water can be increased by the electric heater 9 when it is determined that the estimated value of heat storage amount in the hot water storage unit 3 does not reach the desired heat storage amount.

Description

  The present invention relates to a cogeneration system.

  Conventionally, as a kind of cogeneration system, a fuel cell generator that generates electricity with the generation of heat, a hot water storage unit that stores hot water recovered from the exhaust heat of the fuel cell, and hot water is heated using surplus power from the fuel cell There is known a fuel cell system including a heater for performing the above operation. For example, in the fuel cell system described in Patent Document 1 below, in order to prevent the reverse power flow of surplus power, based on the heat storage amount of hot water stored in the hot water storage unit and the predicted value of the demand heat amount in the hot water utilization device. The surplus power of the fuel cell is controlled to be consumed by either the heater or the power consuming device for consuming surplus power.

  By performing such control, for example, when the amount of hot water used is small in summer, it is possible to prevent surplus power from being supplied to the heater, resulting in useless heat energy that is not used.

JP 2007-330009 A

  However, in the fuel cell system described above, the heater is only operated in response to the generation of surplus power. For example, when the amount of hot water used increases in winter, the amount of hot water used is the exhaust heat of the fuel cell. There are cases where the amount of heat recovered and the amount of heat heated by the heater operation when surplus power is generated may be exceeded, and the amount of heat stored in the hot water storage unit may be insufficient.

  FIG. 9 shows an example of time-series changes in the amount of heat demand and the amount of heat storage in the prior art. The horizontal axis indicates time. Here, it is assumed that the operation schedule of the fuel cell system is determined so that the operation of the fuel cell system starts at 6 o'clock and ends at 23:00. The vertical axis | shaft of FIG. 9 shows calorie | heat amount (demand heat amount and heat storage amount). When the amount of stored heat reaches the upper limit (10 MJ in the example of FIG. 9), no more heat can be stored in the hot water storage tank, so the fuel cell system stops generating power or dissipates heat from the radiator to operate the fuel cell system. Will continue. A bar graph shows the predicted value of the amount of heat demand from the facility at each time. The slanted line portion on the lower left indicates that an unscheduled heat demand that is not included in the predicted value of the demand heat amount has occurred. Although the slanted line portion on the right side is included in the predicted value of the demand heat quantity, it indicates that no demand actually occurred.

  The solid line graph in FIG. 9 represents a change in the predicted value of the heat storage amount at the current time of 0:00. According to this, it is predicted that a shortage of heat storage will occur from 19:00 to 21:00. However, when there is an unplanned demand for heat, such as the slanted area at the left of the 11 o'clock and 12 o'clock, or the slanted area at the right of the 13 o'clock or 17 o'clock However, the actual amount of heat storage changes like a chain line because there may be a case where the heat demand that is scheduled for is not generated. In addition, when unscheduled heat demand occurs at 11:00 and 12:00, and when heat demand occurs as planned at 13:00 and 17:00, the amount of heat stored in the 13:00 range as shown by the one-dot chain line graph. Insufficiency occurs, and a shortage of heat storage occurs again from 18:00 to 21:00.

  As described above, it has been difficult to secure a desired heat storage amount with the prior art.

  Then, an object of this invention is to provide the cogeneration system which can ensure desired heat storage amount, for example, without enlarging a hot water storage unit.

  In order to achieve the above object, a cogeneration system according to the present invention is a cogeneration system that supplies electric power and hot water to a predetermined facility, and includes a power generation unit that generates electric power and heat, and heat generated by the power generation unit. A hot water storage unit for storing hot water warmed by the heater, a heater for increasing the temperature of the hot water stored in the hot water storage unit, and a control means for controlling the heater based on a predicted value of the heat storage amount in the hot water storage unit. Features.

  According to this cogeneration system, the heater is controlled by the control means based on the predicted value of the heat storage amount in the hot water storage unit. Therefore, when it is determined that the predicted value of the heat storage amount in the hot water storage unit does not reach the desired heat storage amount, the temperature of the hot water can be raised by the heater. This makes it possible to secure a desired amount of heat storage without increasing the size of the hot water storage unit, for example.

  The heater operates at least by the electric power generated by the power generation unit, and raises the temperature of the hot water by supplying the amount of heat generated by the operation as an auxiliary heat amount to the hot water storage unit. Actual measured value of heat storage amount, predicted value of demand heat amount in facility, operation schedule of heater, predicted value of auxiliary heat amount stored in hot water storage unit by operating heater, hot water storage by operating power generation unit Calculate and store the predicted value of the recovered heat amount recovered by the unit, and calculate the predicted value of the heat storage amount within a predetermined time from the current time by calculation every unit time, and predict the demand heat amount from the predicted value of the heat storage amount If the value obtained by subtracting the value is smaller than the predetermined lower limit heat storage amount, it is determined that there is a possibility that the heat storage amount may be insufficient. Before time heat storage shortage is expected to occur may be aspects of updating the operation schedule of the heater to heat accumulation auxiliary heat to the hot water storage unit driving a pre-heater.

  According to this, when the predicted value of the heat storage amount of the hot water storage unit within a predetermined time from the current time is calculated by the control means, and the value obtained by subtracting the predicted value of the demand heat amount from the predicted value of this heat storage amount is smaller than the lower limit heat storage amount Before the time when the heat storage amount is expected to be insufficient, the heater is operated in advance, and the auxiliary heat amount is stored in the hot water storage unit. Therefore, the prediction accuracy of the heat storage amount in the hot water storage unit can be increased, and as a result, the occurrence of insufficient heat storage can be suppressed. Here, the lower limit heat storage amount is zero or a positive value.

  The control means further stores the operation schedule of the cogeneration system, and according to the operation schedule, when the cogeneration system is scheduled to stop at the time when the heater should be operated, the operation start time of the cogeneration system It is good also as a mode which updates the driving schedule of a cogeneration system.

  According to this, since the heat storage opportunity to the hot water storage unit by a heater can be ensured for a long time, generation | occurrence | production of insufficient heat storage can be suppressed.

  Further, the heater can further operate by receiving power supply from a commercial power source, and the control means further stores the operation schedule of the cogeneration system, and operates the heater according to the operation schedule. In the case where the cogeneration system is scheduled to stop at a power time, it is possible to operate the heater by supplying power from the commercial power source to the heater while the cogeneration system is stopped.

  According to this, since the heat storage opportunity to the hot water storage unit by a heater can be ensured for a long time, generation | occurrence | production of insufficient heat storage can be suppressed.

  Further, the control means may compare the predicted value of the heat storage amount per unit time obtained by calculation with the predicted value of the demand heat amount after the next unit time to predict whether the heat storage amount is insufficient or not. .

  According to this, before the heat demand is generated, it is possible to reliably secure the expected amount of heat demand, so that it is possible to suppress the occurrence of insufficient heat storage.

  Further, the control means may compare the predicted value of the heat storage amount per unit time obtained by calculation with the predicted value of the demand heat amount at the same time to predict whether or not the heat storage amount is insufficient.

  According to this, since the operation schedule of the heater is determined based on the heat storage amount of the hot water storage unit at the current time, the operation frequency of the heater can be minimized.

  In addition, when the heater is operated, the control means performs heating so that the predicted value of the heat storage amount is expected to exceed an arbitrarily determined upper limit heat storage amount so that the heater is stopped during the time zone. The operation schedule of the vessel may be updated.

  Even if the heater is operated in a state in which the hot water storage unit cannot store heat any more, heat cannot be stored. Thus, it is possible to prevent the heater from being operated in vain. Here, the upper limit heat storage amount is a value that is larger than the lower limit heat storage amount and equal to or less than the maximum heat storage amount that the hot water storage unit can store.

  Moreover, a control means is good also as an aspect which controls a heater so that the heat storage amount in a hot water storage unit may increase, when it is judged that the predicted value of a heat storage amount becomes below a predetermined heat storage amount.

  According to this, it is possible to prevent the heat storage amount from being insufficient such that the heat storage amount in the hot water storage unit is equal to or less than the predetermined heat storage amount.

  According to the present invention, for example, a desired amount of heat storage can be ensured without increasing the size of the hot water storage unit.

1 is a block diagram schematically showing a first embodiment of a cogeneration system according to the present invention. FIG. It is a figure which shows the example of the time series change of the predicted value of demand electric energy, the predicted value of generated electric power according to the demand electric energy, and the predicted value of heat storage amount. It is a flowchart which shows the process sequence in the cogeneration system shown by FIG. 4 is a flowchart showing details of a processing procedure in FIG. 3. It is a figure which shows the example of the time-sequential change of the demand heat amount and heat storage amount in 1st Embodiment. It is a flowchart which shows the detail about the process sequence of 2nd Embodiment. It is a flowchart which shows a part of processing procedure of FIG. It is a figure which shows the example of the time series change of the demand heat amount and heat storage amount in 2nd Embodiment. It is a figure which shows the example of the time-sequential change of the demand heat amount and heat storage amount in a prior art.

  Hereinafter, an embodiment of a cogeneration system according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a fuel cell system 1 as a cogeneration system is installed for home use and supplies electric power and hot water to a home, for example, a fuel cell unit (power generation unit) 2, a hot water storage unit 3 and an operation control device (control means) 20.

  The fuel cell unit 2 generates electric power and heat by using raw fuel. The fuel cell unit 2 includes a reformer 6 and a solid polymer cell stack 7. The reformer 6 contains a reforming catalyst therein, and reforms the raw fuel and water with the reforming catalyst to generate a reformed gas containing hydrogen. As the raw fuel, hydrocarbon gas fuels such as natural gas, LPG (liquefied petroleum gas) and city gas, and hydrocarbon liquid fuels such as kerosene can be used. The reformer 6 is provided with a vaporizer for vaporizing water supplied from the outside, a burner for heating the reforming catalyst to a temperature necessary for the reforming reaction (none of which is shown). It is done.

  The cell stack 7 is formed by laminating a plurality of cells called PEFC (Polymer Electrolyte Fuel Cell). Each cell is configured by disposing an electrolyte, which is a polymer film, between a fuel electrode and an air electrode. In the cell stack 7, the reformed gas generated by the reformer 6 is introduced to the fuel electrode side, and air is introduced to the air electrode side. As described above, the cell stack 7 generates power using the reformed gas and air (oxygen). The electric power generated by the cell stack 7 is output to electric appliances in the home via the power line. The off gas of the reformed gas introduced to the fuel electrode side of the cell stack 7 is supplied to the burner of the cell stack 7 and reused.

  Further, the fuel cell unit 2 is provided with a heat exchanging unit 8 and an electric heater (heater) 9. The heat exchanging unit 8 has a flow path of water disposed between the cells of the cell stack 7, collects heat generated in the cell stack 7, and is connected between the heat exchanging unit 8 and the hot water storage unit 3. Heat is transferred to the water in the heat recovery pipes L1 and L2 for circulating water. The hot water heated by the heat exchanging unit 8 (for example, about 65 ° C.) is stored in the hot water storage tank 11 of the hot water storage unit 3.

  The electric heater 9 is a temperature raising means that is provided in the heat recovery pipe L <b> 2 and further raises the temperature of the hot water heated by the heat exchange unit 8. The electric heater 9 is connected to the power line from the cell stack 7 and is also connected to the system power supply, and can be operated by both the power generated by the cell stack 7 and the power from the system power supply. Yes. More specifically, the electric heater 9 is controlled by the operation control device 20 to heat the hot water in the heat recovery pipe L2, thereby raising the temperature of the hot water stored in the hot water tank 11 (for example, to about 80 ° C.). . In addition, this electric heater 9 heats the hot water in the heat recovery pipe L2 by using the surplus when the surplus that is not used at home is generated in the electric power generated by the cell stack 7. Also serves as a surplus power heater.

  The hot water storage unit 3 has a hot water storage tank 11 and a backup boiler 12. The hot water storage tank 11 is a container having a substantially cylindrical shape, and stores hot water warmed by the heat exchanging unit 8. The hot water storage tank 11 is connected to the heat recovery pipe L2 in the upper part, and is configured such that the hot water transferred by the heat exchanging unit 8 can flow in through the heat recovery pipe L2. The hot water storage tank 11 is connected to the heat recovery pipe L1 in the lower part, and the hot water stored in the lower part of the hot water storage tank 11 flows out to the heat exchange unit 8 by the pump 13 provided in the heat recovery pipe L1. It is configured to be able to send water. In addition, a thermometer T that detects the temperature of hot water stored in the hot water tank 11 is provided in the hot water tank 11. The thermometer T detects the temperature of the hot water stored in the hot water tank 11 and outputs temperature information indicating the detected temperature to the operation control device 20. A plurality of thermometers T may be arranged on the inner wall of the hot water tank 11 so as to be spaced apart at an arbitrary interval in the vertical direction. As the thermometer T, a thermocouple, a thermistor, or the like is used, but is not limited to this.

  The three-way valve 14 can cause the hot water transferred from the heat exchanging unit 8 to flow into the hot water storage tank 11, or can repeatedly introduce the hot water into the heat exchanging part 8 without flowing into the hot water storage tank 11.

  The temperature of the hot water stored in the hot water storage tank 11 is, for example, about 65 ° C. in the case of only heat transfer in the heat exchanging unit 8, but when the electric heater 9 is activated by being controlled by the operation control device 20, That is, it can rise to 70 ° C to 80 ° C.

  Furthermore, the hot water tank 11 is connected to the water supply pipe L3 on the lower side, and clean water is supplied to the lower side of the hot water tank 11 via the water supply pipe L3. The hot water storage tank 11 is connected to the hot water supply pipe L4 on the upper side, and hot water can be discharged from the upper side of the hot water storage tank 11 through the hot water supply pipe L4. A flow meter F1 and a flow meter F2 are provided in the water supply pipe L3 and the hot water supply pipe L4, respectively. The flow meter F1 and the flow meter F2 respectively measure the flow rate of water flowing through the pipes L3 and L4 and the hot water discharged from the hot water storage tank 11, and output the measured flow rate information to the operation control device 20.

  A backup boiler 12 is provided in the hot water supply piping L4 of the hot water storage unit 3. The backup boiler 12 has a burner part that combusts the raw fuel, and heats the hot water when the temperature of the hot water discharged through the hot water piping L4 does not reach a desired temperature.

  The operation control device 20 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, and the like. Further, when the fuel cell unit 2 or the hot water storage unit 3 is provided with a CPU, ROM, RAM, etc., it may operate by using the hardware resources. The operation control device 20 includes a calculation unit 21, a standard data storage unit 22, and an update data storage unit 23.

  The calculation unit 21 controls the entire system of the fuel cell system 1. More specifically, the calculation unit 21 controls power generation in the cell stack 7 according to the amount of power demand at home, and controls the electric heater 9 according to demand power or amount of heat demand at home. Moreover, the calculating part 21 calculates the amount of electric power demand and amount of heat in a home, the amount of electric power generated in the cell stack 7 based on the amount of electric power demand, and the amount of heat stored in the hot water storage unit 3 based on the amount of electric power generated and the amount of heat demand. It has a function.

  The calculation unit 21 is based on information output from, for example, an ammeter connected to the system power supply, an ammeter connected to the fuel cell unit 2, the thermometer T of the hot water storage unit 3, the flow meters F1 and F2, and the like. The amount of electric power, the amount of heat demand, the amount of generated power, and the amount of stored heat are calculated. Further, the calculation unit 21 calculates the operation schedule of the electric heater 9 and the amount of recovered heat stored in the hot water storage unit 3 by operating the fuel cell unit 2. When calculating the demand power amount, the demand heat amount, the generated power amount, the heat storage amount, the operation schedule, and the recovered heat amount, the calculation unit 21 sequentially stores the calculated data in the standard data storage unit 22 corresponding to the date and time. The calculation unit 21 calculates a standard demand power amount, a standard demand heat amount, a standard generated power amount, a standard heat storage amount, a standard recovery heat amount, and the like based on them, determines a standard power generation schedule of the cogeneration system, and updates it each time. Go. Moreover, the calculating part 21 extracts the information corresponding to an operation date from the information memorize | stored in the standard data memory | storage part 22, and performs what is called a learning driving | operation based on the extracted information.

  Furthermore, in the operation control device 20 of the present embodiment, the calculation unit 21 controls the electric heater 9 based on the heat storage amount and the demand heat amount stored in the standard data storage unit 22 and the update data storage unit 23. To do.

  The standard data storage unit 22 is a database that stores history information such as a demand power amount, a demand heat amount, a generated power amount, and a heat storage amount corresponding to the date and time. For example, as shown in the example of FIG. 2, the standard data storage unit 22 stores the daily power demand corresponding to the time (see the broken line in FIG. 2). This amount of power demand may be stored in a single type or a plurality of, for example, every season or every day of the week. An average value of the amount of power demand for the day is calculated and stored in the standard data storage unit 22.

  The standard data storage unit 22 stores heat in the hot water storage tank 11 as the amount of power generated in the fuel cell unit 2 based on the amount of power demand (see the one-dot chain line in FIG. 2) and power generation in the fuel cell unit 2. The amount of stored heat (see the solid line in FIG. 2) is stored. The generated power amount and the heat storage amount may be, for example, one type, or may be stored for each season or for each day of the week. The calculation unit 21 calculates an average value of the generated power amount and the heat storage amount on different days that satisfy certain conditions such as the season and the day of the week, and stores the average value in the standard data storage unit 22. Here, the heat storage amount stored in the standard data storage unit 22 does not include the increase in the heat storage amount due to the operation of the electric heater 9 described above. In FIG. 2, the unit in the demand power amount and the generated power amount is kW (× 0.1), and the unit in the heat storage amount is MJ.

  Further, the standard data storage unit 22 stores the daily demand heat quantity corresponding to the time (see the two-dot chain line in FIG. 2). This demand heat quantity may also be one type, for example, and may be stored for each season or for each day of the week. The calculation unit 21 calculates the average value of the demand heat quantity on a plurality of different days that satisfy certain conditions such as the season and the day of the week, and stores them in the standard data storage unit 22.

  The demand power amount, the demand heat amount, the generated power amount, and the heat storage amount stored in the standard data storage unit 22 as described above are the predicted value of demand power, the predicted value of demand heat amount, the predicted value of generated power amount, respectively. It corresponds to the predicted value of heat storage amount.

  The amount of power demand, the amount of heat demand, the amount of generated power, and the amount of heat storage stored in the standard data storage unit 22 are not limited to a database obtained based on actual operation history. Alternatively, typical numerical data may be given according to the scale of the fuel cell unit 2 or the hot water storage unit 3 installed.

  The update data storage unit 23 stores each data updated by the calculation unit 21.

  Next, the operation in the fuel cell system 1 will be described with reference to FIGS. Each process shown in FIG. 3 is repeatedly executed by the operation control device 20 while the fuel cell system 1 is activated. The day when the fuel cell system 1 is operated and the following processing is executed is referred to as “operation day”.

Here, a processing procedure in the fuel cell system 1 will be described with reference to FIG. First, the calculation unit 21 _reads from the standard data storage unit 22 the standard power generation schedules Sgp _{(X_std) to} Sgp _{(X + Y_std)} of the fuel cell system 1 from the current time X to Y hours later, and the standard demand heat quantity Qdp _{( X_std) to} Qdp _{(X + Y_std)} and standard recovered heat Qgp _{(X_std) to} Qgp _{(X + Y_std)} recovered by operating the fuel cell system 1 are acquired from the standard data storage unit 22.

Then, the calculation unit 21 converts the acquired data into the updated power generation schedules Sgp _{(X) to} Sgp _{(X + Y)} of the fuel cell system 1 in the update data storage unit 23, the predicted value Qdp _(X) of the demand heat amount from the facility, Qdp _{(X + Y)} and stored as update data of predicted values Qgp _{(X) to} Qgp _{(X + Y)} of the recovered heat amount recovered by operating the fuel cell system 1 (more specifically, the fuel cell unit 2) ( S100). At this time, the operation schedules Shp _{(X) to} Shp _{(X + Y)} of the electric heater 9 are all temporarily stopped, and the auxiliary heat quantity Qhp _{(X) to} Shp _{(X + Y)} stored in the hot water storage unit by operating the electric heater 9. Are temporarily set to 0.

Next, the calculating part 21 acquires measured value Qsa _(x-1) of the heat storage amount of the hot water tank 11 at the end of the previous time (S200). And the calculating part 21 starts the driving | operation of the fuel cell system 1 with reference to the update data memorize | stored by step S100 (S300).

Next, the calculation unit 21 updates the various update data stored in the update data storage unit 23 again based on the update data acquired in S100 and the actually measured heat storage amount Qsa _(x-1) acquired in Step S200. (S400). Accordingly, the fuel cell system 1 is operated by the operation control device 20 based on the update data updated in step S400.

When an arbitrary predetermined time (for example, 1 hour) elapses from the current time X (S500), the calculation unit 21 acquires the heat storage amount Qsa _(X) of the hot water storage unit at the end of the current time X (S600).

Then, the calculation unit 21 increments the current time X (S700), and from the standard data storage unit 22, the power generation schedule Sgp _{(X + Ystd)} and the standard demand heat quantity Qdp _{(X + Y_std )} of the fuel cell system 1 after Y hours from the current time X. _{) And} the standard recovery heat quantity Qgp _{(X + Y_std)} are newly acquired, and each acquired data is stored in the update data storage unit 23 (S800). And it returns to step S400 again and repeats step S400-S800.

  Here, detailed processing in step S400 of FIG. 3 will be described with reference to FIG.

First, the calculation unit 21 initializes a character t for increment processing used for calculation (S401). Next, the calculation unit 21 predicts the heat storage amount Qsp _{(X) to} Qsp from the current time _{X to X} + Y based on the actual measurement value of the heat storage amount Qsa _(X-1) of the hot water tank 11 acquired in step S400. _{(X + Y)} is updated (S402). Specifically, for example, the predicted value of the heat storage amount can be obtained by the following equation (1).

Next, the computing unit 21 compares the predicted value Qsp _{(X + t) of} the heat storage amount updated in step S402 with the predicted value Qdp _{(X + t + 1) of} the demand heat amount (S403). That is, the computing unit 21 compares the predicted value of the heat storage amount per unit time with the predicted value of the demand heat amount after the next unit time. Moreover, the predicted value Qdp _{(X + t + 1)} of the demand heat quantity corresponds to a predetermined heat storage amount and also corresponds to a predetermined lower limit heat storage amount.

When the predicted value Qs _{(X + t)} of the heat storage amount is smaller than the predicted value Qd _{(X + t + 1)} of the demand heat amount, the predicted value Qd _{(X + t + 1)} of the demand heat amount cannot be covered only by the heat storage amount Qs _{(X + t)} in the hot water tank 11. is expected. Therefore, the calculation unit 21 calculates the operation time Z ₀ required to supplement the heat quantity ΔQ (= Qd _{(X + t + 1)} −Qs _{(X + t)} ), which is expected to be insufficient, as an auxiliary heat quantity in the operation of the electric heater 9 (S404). ). Specifically, for example, the necessary operation time may be obtained by dividing the heat amount ΔQ that is expected to be insufficient by the heat storage amount Qh that the electric heater 9 generates per unit time. In that case, the operation time Z ₀ can be obtained by the following equation (2).

Then, the arithmetic unit 21, when the Z = Z ₀ when the quantity of thermal storage operation time required to compensate for Z is less than t, operating time Z required to compensate for the heat storage amount is larger than t is , Z = t (S405).

Then, the calculation unit 21 updates the operation schedules Sh _{(X) to} Sh _{(X + t)} of the electric heater 9 so that the electric heater 9 is operated for Z hours between the current time X and the current time X + t (S406). For example, the updated schedule is a schedule in which the operation of the electric heater 9 is started from a time that is Z hours earlier than the time X + t at which the occurrence of a shortage of heat is predicted, and the operation is stopped after Z hours, or The schedule which starts operation of a heater and stops it after Z time may be sufficient.

And the calculating part 21 adds auxiliary heat amount Qhp _(X) -Qhp _{(X + 1)} in the case of operating the electric heater 9, and predicts Qsp _(X) -Qsp _{(X + Y )} of the heat storage amount of the hot water storage tank 11. FIG. ₎ Is recalculated, and various update data in the update data storage unit 23 are updated to the recalculation results (S407). Specifically, for example, Formula (1) can be used.

  Thereafter, if t + 1 is smaller than Y in step S408, the calculation unit 21 increments t (S409) and returns to S403. On the other hand, if t + 1 is not smaller than Y in step S408, the process proceeds to S600 in FIG.

In addition, when Qs _(X) is larger than Qd _{(X + t)} in step S403, it is expected that the predicted value Qd _{(X + t)} of the demand heat storage amount can be covered only by the heat storage amount Qs _{(X + t)} in the hot water tank 11. The process proceeds to step S408 without updating the operation schedule of the heater 9.

An example of the time-series change of the demand heat amount and the heat storage amount when the above processing is performed will be described with reference to FIG. FIG. 5 shows an example of time-series changes in the demand heat amount and the heat storage amount in the present embodiment. The horizontal axis indicates time. Here, it is assumed that the operation schedule Sg of the fuel cell system is determined so that the operation of the fuel cell system 1 starts at 6 o'clock and ends at 23:00. The vertical axis | shaft of FIG. 5 shows calorie | heat amount (demand heat amount and heat storage amount). When the amount of heat stored cannot be stored any more, so-called full storage (10 MJ in the example of FIG. 5), the power generation of the fuel cell system is stopped or the heat is dissipated by a radiator (not shown). Driving will continue. The bar graph indicates the predicted value Qsp _(X) of the demand heat quantity from the facility at each time. The slanted line portion on the lower left indicates that an unscheduled heat demand that is not included in the predicted value Qsp of the demand heat quantity has occurred. Although the slanting line part to the lower right is included in the predicted value Qsp of the demand heat quantity, it indicates that no demand actually occurred.

For example, control for performing the process of predicting the predicted value Qsa _(X) of the heat storage amount of the hot water tank 11 at each time from the current time to 6 hours later will be described. The recovered heat amount Qg stored in the hot water storage tank 11 by power generation is 1 J / hour, and the auxiliary heat amount Qh stored in the hot water storage tank 11 by operating the electric heater 9 is 0.5 / hour. Let the lower limit heat storage amount be 0 MJ.

(Current time X = 0 o'clock)
Assuming that the current time is 0 o'clock, the heat storage amount Qsa ₍₂₃₎ at the end of the 23 o'clock the previous day is 4 MJ. The predicted values Qdp _{(0) to} Qdp ₍₅₎ of the demand heat quantity from the current time to the 5 o'clock range, which is the sixth hour, are ₀ MJ. Moreover, since the operation start time of the fuel cell system 1 is 6 o'clock, the recovered heat amounts Qgp _{(0) to} Qgp ₍₅₎ due to the operation of the fuel cell system 1 are also ₀ MJ. Similarly, since the operation of the electric heater 9 is not performed, the auxiliary heat amounts Qhp _{(0) to} Qhp ₍₅₎ due to the operation of the electric heater 9 are also ₀ MJ. Therefore, the predicted values Qsp _{(0) to} Qsp ₍₅₎ of the heat storage amount in the hot water storage tank 11 are 4 MJ.

(Current time X = 1 o'clock)
When the current time is 1 o'clock without any unscheduled demand for heat, the measured value Qsa ₍₀₎ of the heat storage amount at the end of the 0 o'clock range is 4 MJ. The predicted value Qdp ₍₆₎ of the demand heat quantity at 6 o'clock, which is the sixth hour from the current time, is 1 MJ, and the predicted value Qsp ₍₅₎ of the heat storage quantity at the end of the 5 o'clock is 4 MJ. Further, at 6 o'clock, the recovered heat amount 1 MJ obtained by operating the fuel cell system 1 is stored. As a result, the predicted value of the heat storage amount of the hot water storage tank 11 at the end of the 6 o'clock range is 4 MJ.

(Current time X = 3 o'clock)
When the current time is 3 o'clock without any unscheduled demand for heat, the measured value Qsa ₍₂₎ of the heat storage amount at the end of 2 o'clock is 4 MJ. Predicted value Qdp ₍₈₎ = ₈ MJ of demand heat quantity at 6 o'clock from the current time, and predicted value Qsp ₍₇₎ = 2 MJ at the end of 7 o'clock. It is expected that a 1MJ heat storage shortage will occur. Therefore, the arithmetic unit 21, 7 o'clock in the heat storage amount of the predicted value _{Qsp (7)} is, operation schedule _Sh (3) of the electric heater 9 to exceed the 8 o'clock demand heat _{Qdp (8) ~Sh (8 )} . Since the amount of heat that can be supplemented by operating the electric heater 9 is 0.5 MJ / hour, when supplementing 1 MJ, it is necessary to operate the electric heater 9 for only two hours. In the control of FIG. 5, the calculation unit 21 operates the operation schedules Sh _{(3) to} Sh _{(8 )} so that the electric heater 9 is operated for 2 hours (from 6 o'clock and 7 o'clock) from the operation start time of the fuel cell system 1. ₎ .

(Current time X = 6 o'clock)
When the current time is 6 o'clock without any unscheduled demand for heat, the measured value Qsa ₍₅₎ of the heat storage amount at the 5 o'clock end is 4 MJ. Since the operation of the electric heater 9 starts at 6 o'clock, the predicted value Qsp ₍₆₎ of the heat storage amount at the end of the 6 o'clock range is the actual heat storage amount Qsa ₍₅₎ = 4 MJ in the hot water storage tank 11. Qdp ₍₆₎ = 1 MJ is subtracted, and the recovered heat amount Qg ₍₆₎ = 1 MJ by operating the fuel cell system 1 and the auxiliary heat amount Qh ₍₆₎ = 0.5 MJ by operating the electric heater 9 By adding, it is calculated as 4.5 MJ.

(Current time X = 12: 00)
When an unscheduled heat demand of 1 MJ occurs at 11:00 and the current time is 12:00, the measured value Qsa ₍₁₁₎ of the heat storage amount at the end of the 11:00 is 2 MJ. Accordingly, the calculation unit 21 recalculates and updates Qsa _{(12) to} Qsa ₍₁₇₎ .

(Current time X = 13: 00)
When an unscheduled heat demand of 1 MJ further occurs at 12:00 and the current time is 13:00, the measured value Qsa ₍₁₂₎ of the heat storage amount at the end of the 12:00 is 1 MJ. Predicted value Qdp ₍₁₈₎ = ₁₈ MJ of demand heat quantity at 18:00, which is the sixth hour from the current time, and predicted value Qsp ₍₁₇₎ = 4 MJ at the end of 17:00 It is expected that a shortage of heat storage of 1 MJ will occur again. Therefore, the calculation unit 21 operates the operation schedules Sh _{(13) to} Sh _{( 18)} of the electric heater 9 so that the predicted value Qsp ₍₁₇₎ of the heat storage amount at 17:00 exceeds the demand heat amount Qdp ₍₁₈₎ at _{18:00. )} . In the control of FIG. 5, the calculation unit 21 sets the operation schedules Sh _{(13) to} Sh ₍₁₈₎ so that the electric heater 9 is operated for 2 hours (13:00 and 14:00) from the current time of 13:00. Update.

(Current time X = 14: 00)
When the current time is 14:00 without an unscheduled demand for heat after 13:00, the measured value Qsa ₍₁₃₎ of the heat storage amount at the end of _13:00 is 2MJ. Predicted value Qdp ₍₁₉₎ = ₁₉ MJ for 19:00, which is the sixth hour from the current time, and predicted value Qsp ₍₁₈₎ = 2 MJ for the amount of stored heat at the end of 18 o'clock. It is expected that a shortage of heat storage of 1 MJ will occur again. Therefore, the calculation unit 21 operates the operation schedules Sh _{(14) to} Sh _{( 19)} of the electric heater 9 so that the predicted value Qsp ₍₁₈₎ of the heat storage amount at 18:00 exceeds the demand heat amount Qdp ₍₁₉₎ at _{19:00. )} . In the control of FIG. 5, since the electric heater 9 is scheduled to be operated at 14:00 with the update at 13:00, the calculation unit 21 performs the electric heater only for 2 hours (15:00 and 16:00) from 15:00. The operation schedules Sh _{(14) to} Sh ₍₁₉₎ are updated so as to drive 9.

(Current time X = 15: 00)
When the current time is 15:00 without an unscheduled demand for heat after 14:00, the measured value Qsa ₍₁₄₎ of the heat storage amount at the end of the 14:00 range is 4 MJ. Predicted value Qdp ₍₂₀₎ = 2MJ of demand heat quantity at 20:00, which is the sixth hour from the current time, and predicted value Qsp ₍₁₉₎ = 1 MJ at the end of _19:00 It is expected that a shortage of heat storage of 1 MJ will occur again. Therefore, the calculation unit 21 operates the operation schedules Sh _{(15) to} Sh _{( 20)} of the electric heater 9 so that the predicted value Qsp ₍₁₉₎ of the heat storage amount at _19:00 exceeds the demand heat amount Qdp ₍₂₀₎ at _{20:00. )} . In the control of FIG. 5, since the electric heater 9 is scheduled to be operated at 15:00 and 16:00 with the update at 13:00 and 14:00, the calculation unit 21 operates for 2 hours (from 17:00 and 17:00). The operation schedules Sh _{(15) to} Sh ₍₂₀₎ are updated so that the electric heater 9 is operated only at 18:00.

(Current time X = 18: 00)
When the demand for heat of 1 MJ scheduled for the 17:00 range does not occur and the current time is 18:00, the measured value Qsa ₍₁₇₎ of the heat storage amount at the end of the 17:00 range is 8.5 MJ. Accordingly, Qsa _{(18) to} Qsa ₍₂₃₎ are recalculated and updated. Then, in the update at 15:00, it was predicted that the heat storage amount of 1MJ would be insufficient at 20:00, but due to the absence of 1MJ heat demand scheduled at 17:00, Therefore, it is predicted that a shortage of heat storage will not occur even if the electric heater 9 is not operated. Therefore, the calculation unit 21 updates the operation schedules Sh _{(18) to} Sh ₍₂₃₎ of the electric heater 9 so as to cancel the operation of the electric heater 9 scheduled at about 18:00.

Thereafter, similarly, the calculation unit 21 repeats the acquisition and measurement of the measured value Qsa _(X) of the heat storage amount, the calculation value Qsp _{(X) of} the heat storage amount, and the operation schedule Sh _(X) of the electric heater 9.

  The solid line graph in FIG. 5 represents the change in the predicted value of the heat storage amount at the current time of 0:00. The broken line graph in FIG. 5 shows the amount of heat storage when unscheduled heat demand occurs at 11:00 and 12:00, and the planned heat demand does not occur at 13:00 and 17:00. Represents change. The one-dot chain line graph of FIG. 5 shows the change in the amount of stored heat when unscheduled heat demand occurs at 11:00 and 12:00, and otherwise, heat demand occurs as expected. If these are compared with each graph of FIG. 9, it turns out that the frequency of occurrence of insufficient heat storage is reduced in any case.

  According to the fuel cell system 1 of the present embodiment, the electric heater 9 is controlled by the operation control device 20 based on the predicted value of the heat storage amount in the hot water storage unit 3. Therefore, when it is determined that the predicted value of the heat storage amount in the hot water storage unit 3 does not reach the desired heat storage amount, the temperature of the hot water can be increased by the electric heater 9. In particular, it is possible to secure a desired amount of stored heat without increasing the size of the hot water storage unit 3, for example, because the amount of stored heat can be ensured in preparation for a time zone in which a large amount of heat demand is expected. The supply stability of heat energy by the unit 3 can be improved.

  Furthermore, when the value obtained by subtracting the predicted value of the demand heat amount from the predicted value of the heat storage amount is smaller than the lower limit heat storage amount, the electric heater 9 is operated in advance before the time when the shortage of the heat storage amount is expected to occur. The auxiliary heat quantity is stored in the unit 3. Therefore, the prediction accuracy of the heat storage amount in the hot water storage unit 3 is increased, and as a result, the occurrence of insufficient heat storage is reduced.

  Further, the operation control device 20 compares the predicted value of the heat storage amount per unit time with the predicted value of the demand heat amount after the next unit time, and predicts whether or not the heat storage amount is insufficient. As a result, it is possible to reliably secure the expected amount of heat demand before heat demand is generated, so that the occurrence of insufficient heat storage can be suppressed.

  Moreover, it is possible to prevent the heat storage amount from being insufficient such that the heat storage amount in the hot water storage unit 3 is equal to or less than the predetermined heat storage amount.

Next, a processing procedure in the fuel cell system according to the second embodiment will be described with reference to FIGS. 6 and 7. The fuel cell system according to the second embodiment is different from the fuel cell system 1 according to the first embodiment shown in FIG. Specifically, the processing procedure shown in FIG. 3 is the same, but the detailed processing after obtaining the actually measured heat storage amount Qp _(X) at the current time X in S400 of FIG. 3 is different. In the following description, the description of the same steps as those in FIG. 4 is omitted.

As shown in FIG. 6, after calculating the operation time Z ₀ necessary for supplementing the insufficient heat quantity ΔQ (= Qd _{(X + t + 1)} −Qs _{(X + t)} ) as an auxiliary heat quantity in the operation of the electric heater 9, The unit 21 updates the operation schedule of the electric heater 9 (S420). In step S420, the process shown in FIG. 7 is executed. The electric heater 9 operates using the power generated by the fuel cell system, but the fuel cell system may not be in an operating state at a time when the electric heater 9 is desired to be operated. Therefore, as shown in FIG. 7, the calculation unit 21 acquires the time W when the fuel cell system is scheduled to be operated and the operation of the electric heater 9 is not scheduled at the current time X to X + t (S410). .

The arithmetic unit 21 includes a driving time Z ₀ required assuming that compensate for the lack of heat only in the operation of the electric heater 9 is compared with the time W (S411).

When the operation time Z ₀ required to compensate for the shortage of heat in the operation of the electric heater 9 is larger than the time W, the shortage of heat cannot be compensated for by the operation of the electric heater 9 alone. Request advance time _{Z 1} of the operation start time (S412). Specifically, for example, the advance time can be obtained by the following equation (3).

Further, the arithmetic unit 21 is determined by initially scheduled time Z ₂ to operate the electric heater 9 to the operation start time later have the fuel cell system following equation (4).

The arithmetic unit 21 determines the operation time of the electric heater _{9 Z (= Z 1 + Z} 2) (S414).

Based on the above calculation results, the calculation unit 21 determines the operation schedule Sg _(X) + Sg _{(X + t)} so that the operation start time of the fuel cell system is advanced by Z ₁ . The arithmetic unit 21 operates the electric heater 9 by Z ₁ hour first time zone advance operation of the fuel cell system, then further operating schedule Sh so as to operate the electric heater 9 by Z ₂ hours _{(X ) To} Sh _{(X + t)} are determined (S415).

Note that, in step S411, the operation time Z ₀ required assuming that compensate for the lack of heat only in the operation of the electric heater 9, the fuel cell system is the scheduled driving and operation of the electric heater 9 is planned If there is time W or less, it is determined that there is no need to advance the starting time of the fuel cell system, similarly to the first embodiment, the operation time Z = Z ₀ of the electric heater 9 (S405) .

An example of time-series changes in the demand heat amount and the heat storage amount when the above processing is performed will be described using FIG. 8 as an example. FIG. 8 shows an example of time-series changes in the demand heat amount and the heat storage amount in the second embodiment. The horizontal axis indicates time. Here, it is assumed that the operation schedule Sg of the fuel cell system is determined so that the operation of the fuel cell system starts at 6 o'clock and ends at 23:00. The vertical axis | shaft of FIG. 8 shows calorie | heat amount (demand heat amount and heat storage amount). The upper limit heat storage amount is 8 MJ lower than full storage, and the lower limit heat storage amount is 1 MJ higher than 0 MJ. The bar graph indicates the predicted value Qsp _(X) of the demand heat quantity from the facility at each time. The slanted line portion on the lower left indicates that an unscheduled heat demand that is not included in the predicted value Qsp of the demand heat quantity has occurred. Although the slanting line part to the lower right is included in the predicted value Qsp of the demand heat quantity, it indicates that no demand actually occurred.

For example, control for performing the process of predicting the predicted value Qsa _(X) of the heat storage amount of the hot water tank 11 at each time from the current time to 6 hours later will be described. The recovered heat amount Qg stored in the hot water storage tank 11 by power generation is 1 J / hour, and the auxiliary heat amount Qh stored in the hot water storage tank 11 by operating the electric heater 9 is 0.5 / hour. Let the lower limit heat storage amount be 0 MJ.

(Current time X = 0 o'clock)
Assuming that the current time is 0 o'clock, the heat storage amount Qsa ₍₂₃₎ at the end of the 23 o'clock the previous day is 4 MJ. The predicted values Qdp _{(0) to} Qdp ₍₅₎ of the demand heat quantity from the current time to the 5 o'clock range, which is the sixth hour, are ₀ MJ. Further, since the operation start time of the fuel cell system is 6 o'clock, the recovered heat amounts Qgp _{(0) to} Qgp ₍₅₎ due to the operation of the fuel cell system are also ₀ MJ. Similarly, since the operation of the electric heater 9 is not performed, the auxiliary heat amounts Qhp _{(0) to} Qhp ₍₅₎ due to the operation of the electric heater 9 are also ₀ MJ. Therefore, the predicted values Qsp _{(0) to} Qsp ₍₅₎ of the heat storage amount in the hot water storage tank 11 are 4 MJ.

(Current time X = 3 o'clock)
When the current time is 3 o'clock without any unscheduled demand for heat, the measured value Qsa ₍₂₎ of the heat storage amount at the end of 2 o'clock is 4 MJ. Predicted value Qdp ₍₈₎ = ₈ MJ of demand heat quantity at 6 o'clock from the current time, and predicted value Qsp ₍₇₎ = 2 MJ at the end of 7 o'clock. In order to maintain 1 MJ which is the lower limit heat storage amount, it is expected that a heat storage amount shortage of 2 MJ will occur. Therefore, the arithmetic unit 21, 7 o'clock in the heat storage amount of the predicted value _{Qsp (7)} is, operation schedule _Sh (3) of the electric heater 9 to exceed the 8 o'clock demand heat _{Qdp (8) ~Sh (8 )} . When supplementing the amount of heat of 2 MJ by operating the electric heater 9, it is necessary to operate the electric heater 9 for only 4 hours, but since the operation start time of the fuel cell system is 6 o'clock, the operation time of the electric heater 9 is Only one hour is missing.

Accordingly, the calculation unit 21 increases the operation start time of the fuel cell system by one hour, and further operates the fuel cell system so that the electric heater 9 is operated from 5 o'clock to 2 hours (5 o'clock and 7 o'clock). Schedule _{Sg (3) ~Sg (8)} , and updates the operation schedule _Sh of the electric heater _{9 (3) ~Sh (8)} .

(Current time X = 12: 00)
When an unscheduled heat demand of 1 MJ occurs at 11:00 and the current time is 12:00, the measured value Qsa ₍₁₁₎ of the heat storage amount at the end of the 11:00 is 2 MJ. Accordingly, the calculation unit 21 recalculates and updates Qsa _{(12) to} Qsa ₍₁₇₎ .

(Current time X = 13: 00)
When an unscheduled heat demand of 1 MJ further occurs at 12 o'clock, and the current time is 13:00, the measured value Qsa ₍₁₂₎ of the heat storage amount at the end of 12 o'clock is 2 MJ. Predicted value Qdp ₍₁₈₎ of demand heat quantity at 18:00, which is the sixth hour from the current time, is 5 MJ, and predicted value Qsp ₍₁₇₎ = 5 MJ at the end of 17:00, so It is expected that a shortage of heat storage of 1 MJ will occur again. Therefore, the calculation unit 21 sets the operation schedule Sh ₍ of the electric heater 9 so that the predicted value Qsp ₍₁₇₎ of the heat storage amount at 17:00 is greater than the demand heat amount Qdp _{(18) at} 18:00 by 1 MJ or more. _{13) to} Sh ₍₁₈₎ are determined. In the control of FIG. 5, the calculation unit 21 sets the operation schedules Sh _{(13) to} Sh ₍₁₈₎ so that the electric heater 9 is operated for 2 hours (13:00 and 14:00) from the current time of 13:00. Update.

(Current time X = 14: 00)
When the current time is 14:00 without an unscheduled demand for heat after 13:00, the measured value Qsa ₍₁₃₎ of the heat storage amount at the end of 13:00 is 3.5 MJ. Predicted value Qdp ₍₁₉₎ = ₁₉ MJ of demand heat quantity at 19:00, which is the sixth hour from the current time, and predicted value Qsp ₍₁₈₎ = 3 MJ at the end of 18:00 It is expected that a shortage of heat storage of 1 MJ will occur again. Therefore, the calculation unit 21 sets the operation schedule Sh _{( )} of the electric heater 9 so that the predicted value Qsp ₍₁₈₎ of the heat storage amount at _18:00 is 1 MJ or more larger than the demand heat amount Qdp _{(19) at} 19:00. _{14) to} Sh ₍₁₉₎ are determined. In the control of FIG. 5, since the electric heater 9 is scheduled to be operated at 14:00 with the update at 13:00, the calculation unit 21 operates only for 2 hours (15:00 and 16:00) from 15:00. The operation schedules Sh _{(14) to} Sh ₍₁₉₎ are updated so that the heater 9 is operated.

(Current time X = 15: 00)
When the current time is 15:00 without an unscheduled demand for heat after 14:00, the measured value Qsa ₍₁₄₎ of the heat storage amount at the end of 14:00 is 5 MJ. Predicted value Qdp ₍₂₀₎ = 2MJ of demand heat quantity at 20:00, which is the sixth hour from the current time, and predicted value Qsp ₍₁₉₎ = 2MJ at the end of _19:00 It is expected that a shortage of heat storage of 1 MJ will occur again. Therefore, the calculation unit 21 sets the operation schedule Sh ₍ of the electric heater 9 so that the predicted value Qsp ₍₁₉₎ of the heat storage amount at _19:00 is 1 MJ or more larger than the demand heat amount Qdp _{(20) at} 20:00. ₁₅₎ -Sh ₍₂₀₎ is determined. In the control of FIG. 5, the electric heater 9 is scheduled to be operated at 15:00 and 16:00 with updates at 13:00 and 14:00, and when the electric heater 9 is operated at around 17:00, the upper limit heat storage amount 8MJ is set. Therefore, the calculation unit 21 updates the operation schedules Sh _{(15) to} Sh ₍₂₀₎ so that the electric heater 9 is operated only for 2 hours from 18:00 (18:00 and 19:00).

(Current time X = 18: 00)
When the demand for heat of 1 MJ, which was scheduled for 17:00, does not occur and the current time is 18:00, the measured value Qsa ₍₁₇₎ of the heat storage amount at the end of _17:00 is 9 MJ. Accordingly, Qsa _{(18) to} Qsa ₍₂₃₎ are recalculated and updated. Then, in the update at 15:00, it was predicted that the heat storage amount of 1MJ would be insufficient at 20:00, but due to the absence of 1MJ heat demand scheduled at 17:00, And even if the electric heater 9 is not operated at around 19:00, it is predicted that there will be no shortage of heat storage. Therefore, the calculation unit 21 updates the operation schedules Sh _{(18) to} Sh ₍₂₃₎ of the electric heater 9 so as to cancel the operation of the electric heater 9 scheduled for the 18:00 and 19:00 hours.

Thereafter, similarly, the calculation unit 21 acquires the actual measurement value Qsa _(X) of the heat storage amount, determines the operation schedule Sh _(X) of the electric heater 9 so as not to fall below the lower limit heat storage amount, and predicts the heat storage amount Qsp. Repeat the calculation and update of _(X) .

  The solid line graph of FIG. 8 represents the change in the predicted value of the heat storage amount at the current time of 0:00. The broken line graph in FIG. 8 shows the amount of heat stored when unscheduled heat demand occurs at 11 o'clock and 12 o'clock, and the heat demand scheduled at 13 o'clock and 17 o'clock does not occur. Represents change. The one-dot chain line graph of FIG. 8 shows changes in the amount of heat storage when unscheduled heat demand occurs at 11:00 and 12:00, and otherwise, heat demand occurs as expected. If these are compared with each graph of FIG. 9, it turns out that the frequency of occurrence of insufficient heat storage is reduced in any case. Moreover, even if compared with each graph of FIG. 5, since the calorie | heat amount more than a lower limit heat storage amount is always ensured, it turns out that the response | compatibility to the demand of unscheduled heat is also improved.

  In addition, even if the demand for heat in the 18 o'clock range is delayed in the chain line graph, the operation of the electric heater 9 in the next hour is stopped in that case, so that the operation of the fuel cell system is continued for one hour thereafter. Can do. As a result, the operation of the fuel cell system can be stopped, or the amount of heat stored by operating the electric heater 9 can be reduced by a radiator or the like.

  According to the fuel cell system of the second embodiment, the same operations and effects as the fuel cell system 1 of the first embodiment are exhibited.

  When the fuel cell system is scheduled to stop at the time when the electric heater 9 should be operated, the operation start time of the fuel cell system is advanced by the control means. Therefore, since the heat storage opportunity to the hot water storage unit 3 by the electric heater 9 can be ensured for a longer time, occurrence of insufficient heat storage can be suppressed.

  In addition, even if the electric heater 9 is operated in a state where the hot water storage unit 3 cannot store heat any more, heat cannot be stored, but the predicted value of the heat storage amount is expected to exceed the upper limit heat storage amount. By stopping the electric heater 9, it is possible to prevent unnecessary operation of the electric heater 9.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment.

  For example, in the first embodiment, the fuel cell system 1 has been described as an example of control that starts operation at 6 o'clock and stops operation at 23:00. However, even if control is not repeated between starting and stopping within 24 hours, It is possible to apply the first embodiment.

  In the second embodiment, the control for advancing the operation start time when the fuel cell system is not expected to be in the operating state at the time when the electric heater 9 is desired to be operated has been described. If the fuel cell system is configured to be able to be operated, the time when the fuel cell system is expected not to be in operation may be a control in which only the electric heater 9 is operated by receiving power supply from the system power supply. . In this case, since the heat storage opportunity to the hot water storage unit 3 by the electric heater 9 can be secured for a longer time, the occurrence of insufficient heat storage can be suppressed.

  Furthermore, in 1st Embodiment and 2nd Embodiment, it controlled so that the heat storage by the electric heater 9 might be completed before the time slot | zone where generation | occurrence | production of insufficient heat storage amount is anticipated, but the upper limit heat storage amount is set. If priority is given to stopping the electric heater 9, or if the amount of stored heat cannot be ensured only by the operation of the electric heater 9, the electric heater may be continuously operated even during a time period when the amount of stored heat is insufficient. Of course.

  Moreover, in 1st Embodiment and 2nd Embodiment, the predicted value of the heat storage amount per unit time calculated | required by calculation is compared with the predicted value of the demand heat amount after the following unit time, and the presence or absence of heat storage amount deficiency As an example, the predicted value of the heat storage amount per unit time obtained by calculation is compared with the predicted value of the demand heat amount at the same time to predict whether there is a shortage of heat storage amount. Also good. According to this, it is possible to further suppress the hot water storage unit from being fully stored due to the planned demand for heat not occurring or being delayed. Furthermore, by using together with the embodiment in which the lower limit heat storage amount is set to be greater than 0 MJ, it is possible to achieve both suppression of insufficient heat storage amount of the hot water storage unit and suppression of full storage.

  In the above embodiment, the power generation amount and the recovered heat amount are constant and the auxiliary heat amount obtained by the heater is also constant for easy understanding, but the recovery is performed according to the power generation amount. Of course, the amount of heat may be predicted in detail, and the auxiliary heat amount may be adjusted by changing the operation output of the heater according to the amount of stored heat that is expected to be insufficient.

  The cell stack 7 is not limited to the solid polymer type, and may be an alkaline electrolyte type, a phosphoric acid type, a molten carbonate type, a solid oxide type, or the like.

  Moreover, although the hot water storage unit 3 demonstrated the case where the hot water storage unit 3 had the backup boiler 12 in the said embodiment, by designing and selecting the hot water storage tank of the size suitable for the amount of heat demand of a facility in addition to this invention, the backup boiler 12 itself Can be reduced in size, simplified, or omitted.

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system (cogeneration system), 2 ... Fuel cell unit (power generation unit), 3 ... Hot water storage unit, 9 ... Electric heater (heater), 20 ... Operation control apparatus (control means).

Claims (8)

A cogeneration system that supplies power and hot water to a predetermined facility,
A power generation unit for generating electric power and heat;
A hot water storage unit for storing hot water heated by the heat generated by the power generation unit;
A heater for raising the temperature of the hot water stored in the hot water storage unit;
Control means for controlling the heater based on a predicted value of the amount of heat stored in the hot water storage unit. The heater operates at least by the electric power generated by the power generation unit, and raises the temperature of the hot water by supplying the amount of heat generated by the operation as an auxiliary heat amount to the hot water storage unit,
The control means includes
The measured value of the heat storage amount in the hot water storage unit, the predicted value of the demand heat amount in the facility, the operation schedule of the heater, the predicted value of the auxiliary heat amount stored in the hot water storage unit by operating the heater, and And calculating and storing a predicted value of the recovered heat amount recovered by the hot water storage unit by operating the power generation unit,
Obtain the predicted value of the heat storage amount within a predetermined time from the current time by calculation every unit time,
When the value obtained by subtracting the predicted value of the demand heat amount from the predicted value of the heat storage amount is smaller than a predetermined lower limit heat storage amount, it is determined that there is a possibility that the heat storage amount is insufficient, and the heat storage amount is insufficient. 2. The cogeneration system according to claim 1, wherein the operation schedule of the heater is updated so that the heater is operated in advance and the auxiliary heat quantity is stored in the hot water storage unit before a time when the heater is expected to occur. system. The control means includes
Further storing the operation schedule of the cogeneration system,
According to the operation schedule, when the cogeneration system is scheduled to stop at the time when the heater should be operated, the operation schedule of the cogeneration system is updated so that the operation start time of the cogeneration system is advanced. The cogeneration system according to claim 1 or 2, characterized in that: The heater can be further operated by receiving power supply from a commercial power source,
The control means includes
Further storing the operation schedule of the cogeneration system,
According to the operation schedule, when the cogeneration system is scheduled to be stopped at the time when the heater is to be operated, power is supplied to the heater from a commercial power source while the cogeneration system is stopped. The cogeneration system according to claim 1 or 2, wherein the heater is operated.   The control means predicts whether or not the heat storage amount is insufficient by comparing the predicted value of the heat storage amount per unit time obtained by calculation with the predicted value of the demand heat amount after the next unit time. The cogeneration system according to any one of claims 2 to 4.   The control means compares the predicted value of the heat storage amount per unit time obtained by calculation with the predicted value of the demand heat amount at the same time, and predicts whether or not the heat storage amount is insufficient. Item 5. The cogeneration system according to any one of Items 2 to 4.   When the heater is operated, the control means is configured to stop the heater during the time zone in which the predicted value of the heat storage amount is expected to exceed an arbitrarily determined upper limit heat storage amount. The cogeneration system according to any one of claims 1 to 6, wherein an operation schedule of the heater is updated.   The said control means controls the said heater so that the heat storage amount in the said hot water storage unit may increase, when it is judged that the predicted value of the said heat storage amount becomes below a predetermined heat storage amount. The described cogeneration system.

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