JP4148419B2 - Cogeneration system and control method - Google Patents

Description

  The present invention relates to a cogeneration system using a fuel cell, a gas engine, or the like. More specifically, the present invention relates to control of a cogeneration system that can be used in a general household.

The cogeneration system is a system intended for energy saving and environmental performance (such as low carbon dioxide emissions), and various operation control methods have been proposed so as to maximize the energy saving effect and environmental performance.
In particular, in a cogeneration system having a hot water generating means such as a fuel cell or a gas engine and a hot water storage tank that uses the exhaust heat, setting the operation / start-up time within a day is necessary for energy saving operation. It has become one of the most important items.

  That is, when starting or stopping a fuel cell (FC) once or multiple times a day, when the fuel cell is started (starts operation) and when the fuel cell is stopped It is necessary to decide whether to become an efficient system.

  In other words, at an inappropriate start / stop time, the hot water in the hot water storage tank is not sufficiently stored when the bath is filled, and many auxiliary heat source machines are working, or power is generated during a time when power consumption is low. Since the state of low efficiency continues for a long time and the like leads to a reduction in energy saving and environmental performance, it is important to appropriately determine the operation time zone.

  Here, a technology for predicting the time when the hot water tank is filled with hot water from the predicted power value and hot water supply prediction value of the installation destination home and determining the optimum start time and power generation output has been proposed ( For example, see Patent Document 1).

  However, these technologies are designed to drive once a day for bathing (generally around 7:00 to 9:00), and use a lot of hot water at other times. Home (for example, when the bathing time is different from “around 7 pm to 9 pm”, when bathing many times a day, or during the time when a lot of hot water is used in addition to the bath Etc.) and the correspondence to such a home (or case) is not considered.

For example, as shown in the “electricity and hot water supply demand characteristic diagram” of FIG. 6, shampoo and shower are frequently used in households where hot water is washed every morning or in the morning time zone (hot water supply hot water demand graph Q of FIG. 6 (Qx portion in hot water supply) At home, the cogeneration system stops before the bathing time the night before (hot water storage rate = 100% in hot water tank hot water storage rate diagram T in FIG. 5; fuel cell in hot water tank full (Stopped state), then the hot water is used up in the bath, and the hot water tank becomes nearly empty. The next morning, the hot water in the hot water storage tank will not be able to cover the demand for hot water required for washing, shampooing, and showering, and many auxiliary heat source units will operate, reducing energy conservation and environmental performance. .
That is, if this consumption (hot water consumption in the morning) is covered with hot water in the hot water tank, the fuel cell must be started in the middle of the night when the power consumption is considerably small (around 3 am in FIG. 6). It is not a good idea because it generates power with low efficiency and is inferior in energy saving.
In FIG. 6, a characteristic line We indicates a characteristic line indicating an instantaneous power generation output of the fuel cell.

  Unlike commercial use, cogeneration equipment for home use has various demand patterns depending on the home and house, and it is required that these various patterns can be operated without problems. In other words, the basic performance required for home appliances is to make it compatible with any user (there is “universality”).

In order to build a cogeneration system that can handle any user as described above, calculate all startup / shutdown / output patterns from the household power demand and hot water supply demand patterns and compare them. Then, it may be configured to select the optimum one. However, in order to calculate all start / stop / output patterns and compare them to select the most suitable one, the amount of processing required for calculation, comparison and selection becomes enormous, so-called `` microcomputer '' for home use Cannot be processed.
In other words, the optimum start time, operation end time, and power generation output of the fuel cell are different in each household, and a huge number of patterns must be calculated to cover the optimum operation pattern for each household. Therefore, the calculation amount becomes enormous, and a normal microcomputer requires a long time for processing, which is practically impossible.
JP 2003-45460 A

  The present invention has been proposed in view of the above-mentioned problems of the prior art, and can cope with a wide variety of demand patterns such as ordinary homes, and with a sufficient processing amount with a general microcomputer. An object of the present invention is to provide a cogeneration system that is controllable and does not require the use of a high-performance and expensive processing speed and control means, and a control method therefor.

  According to the cogeneration system of the present invention, in the cogeneration system having hot water generating means (fuel cell 1, gas engine, etc.), control means (control panel 40) and hot water tank (2), the control means (control panel) 40) determines the stop time of the demand prediction means (demand prediction unit 41), the start time determination means (start time determination unit 42) for determining the start time of the hot water generation means (1), and the hot water generation means (1). Stop time determining means (stop time determining unit 43) and time measuring means (time measuring unit 44), and the control means (4) has a bathing time predicted by the demand predicting means (41). The hot water generation means (1) Is temporarily set to the stop time, and the start time of the hot water generating means (1) is set appropriately (for example, by changing the predetermined time by one hour) (S4, 5), and the demand predicted by the demand predicting means (41) is set. Based on the parameters of energy consumption (primary energy consumption), utility costs, and carbon dioxide emissions, the calculated parameters (energy consumption, utility costs, carbon dioxide emissions) The start time at which the parameter) is minimum is selected and determined by the start time determining means (42) as the start time of the hot water generating means (1), the hot water generating means (1) is started at the start time, and after the start The operation pattern is calculated while correcting the power generation output value, and the stop time of the hot water generating means (1) is changed by a predetermined time after the current time to change the energy consumption (primary energy consumption), the utility cost, and the diacid Calculate any parameter of carbon emissions (S14), and select hot water generation by selecting the stop time at which the calculated parameters (parameters of energy consumption, utility costs, carbon dioxide emissions) are minimized It is characterized by having a function of determining the stop time of the means (1) by the stop time determining means (43) (S19).

  According to the present invention, the start time determining means (42) sets the stop time of the hot water generating means (1) by the stop time determining means (43), and then sets the start time of the hot water generating means (1). Energy consumption by changing the start time of the hot water generating means (1) by a predetermined time (for example, 1 hour) every predetermined time (for example, 1 hour). (Primary energy consumption), utilities costs, and carbon dioxide emissions are calculated, and the calculated parameters (energy consumption, utilities costs, and carbon dioxide emissions parameters) are minimum. The process of selecting the starting time to be determined and determining the starting time of the hot water generating means (1) is repeated.

  Further, according to the present invention, the stop time determination means (43) is configured to determine the stop time after the stop time of the warm water generation means (1) (after the warm water generation means (1) is activated) until the stop time is reached. By changing the stop time of the hot water generating means (1) every predetermined time (for example, 1 hour) by a predetermined time (for example, 1 hour), the energy consumption (primary energy consumption), the utility cost, and the carbon dioxide emission amount are changed. Any parameter is calculated, and the stop time at which the calculated parameter (energy consumption, utility cost, carbon dioxide emission parameter) is minimized is determined again as the stop time of the hot water generating means (1). It is comprised so that the process to repeat may be repeated.

  Furthermore, according to the present invention, when a predetermined time (for example, 1 hour) has passed after the hot water generating means (1) is stopped, the predetermined time (for example, 24 hours) when the warm water generating means (1) is started at that time. ) One of the parameters of energy consumption, utility costs, and carbon dioxide emission until the passage of time is calculated based on the demand predicted by the demand prediction means (41), and at that time, the hot water generation means (1) Based on the demand predicted by the demand forecasting means (41), the parameter (any parameter of energy consumption, utility cost, carbon dioxide emission) until a predetermined time (for example, 24 hours) elapses without starting When the warm water generating means (1) is activated at that time, the parameters (until the predetermined time elapses) (energy consumption) , Utility bills, and a restart determining means for determining to restart any parameter) is smaller if the hot water generator of carbon dioxide emissions (1) (restart determination unit 45).

  Here, when it is determined that the warm water generating means (1) is activated (when it is restarted), the stop time of the warm water generating means (1) is changed by a predetermined time (for example, 1 hour) to change the energy consumption (1 Secondary energy consumption), utility costs, carbon dioxide emissions, and stop time when the calculated parameters (energy consumption, utilities costs, carbon dioxide emissions) are minimized Is preferably configured to repeat the process of determining as the stop time of the hot water generating means (1).

  According to the control method of the cogeneration system of the present invention, the control of the cogeneration system (A) having hot water generating means (fuel cell 1, gas engine, etc.), control means (control panel 40) and hot water tank (2). In the method, the hot water generation means (1) stop time is calculated by using the bathing time predicted by the demand prediction means (41) (the bathing occurrence time) or the time predicted to reach the peak of hot water supply demand (hot water supply demand peak prediction time). Is set temporarily (S4, 5), the activation time of the hot water generating means (1) is set appropriately (for example, by changing the predetermined time by one hour) (S6) to the demand predicted by the demand prediction means (41) On the basis of this, one of the parameters of energy consumption (primary energy consumption), utility cost, and carbon dioxide emission is calculated (S7), and the calculated parameter ( A step (S10) of selecting a start-up time that minimizes the energy consumption, utility costs, and carbon dioxide emission parameters (S10), and hot water at the start-up time. A step (S12) of starting the generating means (1) and an operation pattern are calculated while correcting the power generation output value after starting the hot water generating means (1) (S14), and the stop time of the hot water generating means (1) is set to the present time. The parameter is changed by a predetermined time after the time to calculate any parameter of energy consumption (primary energy consumption), utility cost, and carbon dioxide emission (S18), and the calculated parameters (energy consumption, And (S19) a step of selecting a stop time that minimizes the utility cost and the carbon dioxide emission amount) and determining the stop time of the hot water generating means (1). It is.

  And according to this invention, after setting the stop time of a warm water generation means (1) (S4, 5), until it reaches the starting time of a warm water generation means (1), every predetermined time (for example, 1 hour) The set stop time is set to a fixed value and the startup time of the hot water generating means (1) is changed by a predetermined time (for example, 1 hour) to change energy consumption (primary energy consumption), utility cost, and dioxide Calculate any parameter of the carbon emission amount (S7), and select the start-up time that minimizes the calculated parameter (any parameter of energy consumption, utility cost, carbon dioxide emission amount) and generate hot water The process of determining the activation time (1) (S10) is repeated.

  Further, according to the present invention, after the stop time of the hot water generating means (1) is determined, the stop time of the hot water generating means (1) is set to a predetermined time every predetermined time (for example, 1 hour) until the stop time is reached. By changing time (for example, 1 hour), any one parameter of energy consumption (primary energy consumption), utility cost, and carbon dioxide emission is calculated, and the calculated parameters (energy consumption, utility cost) , Any one parameter of carbon dioxide emission amount) is selected, and the process of re-determining the stop time of the hot water generating means (1) is repeated.

  Further, according to the present invention, when the predetermined time (for example, 1 hour) has elapsed (S23) after the hot water generating means (1) is stopped (S21), the hot water generating means (1) is activated at that time. Based on the demand predicted by the demand forecasting means (41), any parameter of energy consumption, utility cost, and carbon dioxide emission until a predetermined time (for example, 24 hours) elapses is calculated (S25). Further, the parameter (any parameter of energy consumption, utility cost, carbon dioxide emission) until a predetermined time (for example, 24 hours) elapses when the hot water generating means (1) is not started at that time is demand prediction means. (41) is calculated based on the demand predicted by (41) (S26), both are compared (S27), and the hot water generating means (1) is started at that time (place Up to) the parameters elapsed time (energy consumption, energy costs, any of the parameters of the carbon dioxide emissions) has the step of restarting the hot water generating means (1) the less (S28).

  Here, when the step of starting the hot water generating means (1) is executed (when restarting; S28), the stop time of the hot water generating means (1) is changed by a predetermined time (for example, 1 hour) to consume energy. Calculate any one of the parameters (primary energy consumption), utility costs, carbon dioxide emissions, and the calculated parameters (energy consumption, utilities costs, carbon dioxide emissions parameters) are the smallest It is preferable to repeat the process of determining the stop time as the stop time of the hot water generating means (1).

According to the present invention having the above-described configuration, the bathing time predicted by the demand prediction means (41) (the bathing occurrence time) or the time when hot water supply demand is predicted to peak (the hot water demand peak predicted time) is calculated. Set the hot water generation means (1) as the stop time, change the start time by a predetermined time (for example, 1 hour), and start the time when any of the parameters of energy consumption, utility cost, and carbon dioxide emission is minimum The time is determined. Therefore, the number of calculations necessary to determine the start time is the time from the prediction time (for example, 3 am) to the set stop time (for example, 18:00), the predetermined time (for example, 1 hour). ) (For example, (18 o'clock-3 o'clock) ÷ 1 hour = 15 times), which is much smaller than the method of calculating all combinations of start time and stop time.
Although the gas engine can start power generation immediately after startup, a fuel cell with a built-in reformer that produces hydrogen from city gas requires about one hour to raise the temperature of the reformer. Therefore, in the above example, when starting at 17:00 and stopping at 18:00, it is stopped only by starting and not generating electricity, so at least 2 hours before is set as the lower limit of starting time. Therefore, in the above example, ((18: 00-2) -3 o'clock) / one hour = 13 times).

  Then, by changing the stop time of the hot water generating means (1) by a predetermined time (for example, 1 hour), any one parameter of energy consumption (primary energy consumption), utility cost, carbon dioxide emission is calculated, Since the stop time at which the calculated parameter (any parameter of energy consumption, utility cost, carbon dioxide emission) is minimized is the stop time of the hot water generating means, the number of times of calculation when determining the stop time is also Then, the time until the stop after starting is divided by the predetermined time (for example, 1 hour) (for example, if the start time is 9 o'clock and the stop time is 19 o'clock (19 o'clock to 9 o'clock)) ÷ 1 hour = 10 times ), The number of times is extremely small compared with the conventional method of calculating all combinations.

In the present invention, it is possible to learn and predict the demand pattern of each household by the demand prediction means (41), and therefore it is possible to perform control corresponding to the demand pattern of each household.
Therefore, when used as a household cogeneration system, it is possible to realize optimal control for a demand pattern that differs for each household.

In particular, in the present invention, after determining the stop time of the hot water generating means (1), the process of determining the start time of the hot water generating means (1) every predetermined time (for example, one hour) until the determined start time is reached. (Claim 2), the actual demand of the hot water generating means (1) is different from the demand forecast, for example, the amount of heat stored in the hot water tank (2) in the fuel cell system is predicted. If the amount of heat storage differs greatly from the time when the stop time was previously determined by being different from the transition of the hot water supply demand, the start time of the hot water generating means (1) can be corrected accordingly.
Further, after determining the stop time of the hot water generating means (1) after the hot water generating means (1) generates power, the process of determining the stop time of the hot water generating means (1) is repeated every predetermined time (for example, 1 hour). (Claim 3), even when the power demand or hot water supply demand is different from the predicted demand pattern after power generation, the stop time can be corrected and dealt with.
And, the corrected start time and stop time can be reflected in the optimal operation (= the parameter of any of energy consumption, utility cost, and carbon dioxide emission is small), so it differs for each household. It is possible to deal with demand patterns with large fluctuations more precisely.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  In FIG. 1, the cogeneration system A has a hot water supply system 10 having a hot water tank 2 and a heat source device 3, a fuel cell 1, and a control panel 40 as control means in the hot water supply system 10. .

The control panel 40 has a control unit 4 which is a control means and has a built-in database 46 (each demand amount measurement value stored in a memory) 46.
In addition, although not clearly shown, an operation plan such as the start time of the fuel cell is drawn up, or the power demand measurement wiring is connected from the distribution board in the house to the control unit 4 in order to determine the operation command. It is connected to the. Although not shown, the control unit 4 and the fuel cell 1 are electrically connected by an operation control command signal cable.

  In the fuel cell 1, water stored in the hot water tank 2 due to exhaust heat generated during power generation by the fuel cell 1 circulates in the fuel cell 1 or the gas engine through the circulation line Lw and is warmed for hot water supply. Hot water is made.

The heat source unit 3 includes a hot water supply backup burner 32 that preheats and heats hot water when the hot water temperature that is interposed in the hot water supply line Lh is low, and a heat exchanger that reheats the bath (not shown). Have.
The heat source device 3 has a circuit board (interface) 31, which connects the control unit 4 with measuring means (flow meter, temperature sensor, etc.), which will be described later, and the backup burner 32. It relays the reception of the input signal and relays the control of the operation / non-operation of the backup burner 32.

  The hot-water supply line Lh is provided with a bypass line Lb for short-circuiting the hot-water supply backup burner 32 at the branch point Pb1 and the junction Pg1 of the hot-water supply line Lh. By switching the switching valve interposed at the branch point Pb1 of Lb, the hot water supply is not preheated, that is, bypassed or preheated by the backup burner 32 without being bypassed. Yes.

  A temperature sensor T10 for measuring the temperature of hot water in the bathtub 5 is interposed in the vicinity of the bathtub 5 on the discharge side of the bath reheating line La. (T10 may be installed in the reheating line La in the hot water supply system 10.)

The terminals of the hot water supply line Lh are connected to the hot water supply port 5W for the bath and the hot water supply port 6 for the kitchen via the branch point Pb3.
A branch point Pb2 is formed in a region between the junction points Pg1 and Pb3 of the hot water supply line Lh. The junction point Pb2 and the junction point Pg2 formed on the return side of the reheating line La are communicated by a line Lc. ing.

A first temperature sensor T1 for measuring a hot water supply temperature is provided in a region between the hot water storage tank 2 and the branch point Pb1 of the hot water supply line Lh, and a region between the junction point Pg1 and the branch point Pb2 is arranged in the order of flow. A second temperature sensor T2 and a first flow meter F1 are interposed.
A third temperature sensor T3 and a second flow meter F2 are interposed in the flow-through line La on the upstream side of the junction Pg2 in order of flow.
A third flow meter F3 is interposed in the line Lc connecting the hot water supply line Lh and the reheating line La.
Further, a water level meter Sw for measuring the amount of hot water (water level) in the bathtub 5 is interposed in a region between the junction Pg <b> 2 of the reheating line La and the bathtub 5.

  The hot water storage tank 2 is supplied with clean water by a clean water supply line Lm. In addition, when hot water is too hot in a region between the hot water storage tank 2 and the first temperature sensor T1 of the hot water supply line Lh, cold water is supplied to the water supply line in order to lower the temperature of the hot water supply (adjust temperature). Piped to be added by Ln.

  The water supply line Lm has a fourth temperature sensor T4 for measuring the temperature of the feed water, and the hot water storage tank 2 has fifth to ninth temperature sensors T5 to T9 in five layers in order from the top. The temperature sensors T4 to T9 are once connected to the connector C, and the connector is connected to the control unit 4 in the home B by a signal line Lt.

  The temperature sensors T1 to T3 and the flow meters F1 to F3 are connected to the circuit board 31, and the circuit board (interface) 31 is connected to the home B via a connector 31c provided on the circuit board 31. The control unit 4 is connected by a signal line Ltf. On the other hand, the database 46 built in the control unit 4 stores information from the sensors on the heat source unit 3 side via the circuit board 31 and the sensors connected to the control unit side.

The configuration of the control unit 4 will be described in detail with reference to FIG.
As described above, the control unit 4 belongs to the control panel 40, and includes a demand prediction unit 41, a start time determination unit 42, a stop time determination unit 43, a timer 44 which is a time measuring means, a restart determination unit 45, It comprises a database 46 and a fuel cell control signal transmission unit 47.

  The database 46 receives information from various sensors via the circuit board (interface) 31, the line Ltf, and the line Lt, and stores the information.

The demand prediction unit 41 predicts hot water supply demand and electric power demand from the data stored in the database 46, and predicts the time when the hot water supply occurs or when the hot water supply demand peaks, and transmits the result to the activation time determination unit. To do. Specifically, as shown in Tables 1 and 2, forecasts are made by recording / learning power demand, hot water supply demand, and bathing demand (only when it occurs) every day of the week (for example, every hour). Sometimes, it is possible to predict each demand of the house by extracting past learning data (each demand pattern) of the same day of the week. Here, the demand prediction method may use a known fact (for example, a neural network method).
The hot water supply demand Qkyu to be recorded / learned is obtained by Qkyu = (hot water temperature t2−water temperature t4) × input water flow rate. Here, “hot water temperature t2” is the measured temperature of the temperature sensor T2 in FIG. 1, “water temperature t4” is the measured temperature of the temperature sensor T4, and “incoming water flow rate” is the measured flow rate of the flow meter F1.
The bath filling demand Qb is obtained by Qb = (bath thermistor temperature t3−water temperature t4) × instantaneous hot water flow rate. Here, “bath thermistor temperature t3” is the measured temperature of temperature sensor T3 in FIG. 1, and “instantaneous hot water flow rate” is the measured flow rate of flow meter F3. However, the temperature based on the “bath set temperature” of the remote controller may be used instead of the “bath thermistor temperature t3”.

  When the activation time determination unit 42 obtains a bathing time predicted by the demand prediction unit 41 (a bathing occurrence time) or a time when hot water supply demand is predicted to reach a peak (hot water supply demand peak prediction time), first, the time is determined. When the fuel cell 1 is set at the stop time, the energy consumption (primary energy consumption), the utility cost, and the carbon dioxide emission are set as parameters, the start time of the fuel cell 1 is set for a predetermined time (for example, from the calculation time). 1 hour) and change based on the demand predicted by the demand prediction unit 41. Then, the start time at which the calculated parameter (any one of energy consumption, utility cost, and carbon dioxide emission amount) is minimized is determined as the start time of the fuel cell 1, and the determined start time is stored in the database 46. It is configured to memorize.

  The stop time determination unit 43 determines the stop time every predetermined time (for example, 1 hour) after determining the stop time of the fuel cell 1 after the fuel cell 1 has generated power after the start time determined by the start time determination unit 42 has elapsed. Until the reached stop time is reached, the fuel cell 1 stop time is changed by a predetermined time (for example, 1 hour from the time of calculation) to select one of energy consumption (primary energy consumption), utility costs, and carbon dioxide emissions. And the process of determining the stop time at which the calculated parameter (any one of energy consumption, utility costs, and carbon dioxide emission) is the minimum as the stop time of the fuel cell 1 is repeated and determined. The stop time is stored in the database 46.

  When the fuel cell 1 is stopped, the restart determination unit 45 consumes energy until a predetermined time (for example, 24 hours) elapses when the fuel cell 1 is started at that time. A predetermined time (for example, 24 hours) when the fuel cell 1 is not started at that time, when any parameter of the amount, utility cost, and carbon dioxide emission is calculated based on the demand predicted by the demand prediction unit 41. ) The parameter (any parameter of energy consumption, utility cost, and carbon dioxide emission) until the elapsed time is calculated based on the demand predicted by the demand prediction unit 41. Then, the two parameters are compared, and when the fuel cell 1 is started up at that time, the parameter (any parameter of energy consumption, utility cost, carbon dioxide emission amount) (until a predetermined time elapses) should be small. For example, the fuel cell 1 is determined to be activated, and data relating to the determined restart is stored in the database 46.

The cogeneration system according to the present embodiment saves the start and stop times of the fuel cell 1 based on the predicted values of daily power demand and hot water supply and bathing demand in order to respond to various demands at home. It is set so that it can be operated optimally in consideration of energy / environmental conservation or operation cost.
The control unit 4 constituting the system is about the same as a normal microcomputer in terms of processing capability, and can sufficiently cope with the information amount and calculation amount from each sensor of the system.
The control unit 4 predicts the hot water supply demand, which is the maximum hot water supply demand per day, and calculates from the electric power demand and the hot water supply demand prediction value so that the necessary amount is accumulated in the hot water storage tank 2 at the hot water supply time. It is calculated at what time the fuel cell 1 is to be activated, and the activation time is determined. In addition, after the start-up, the power generation output and the stop time are periodically reviewed and updated to automatically determine the start / output / stop for any demand.

  Next, based on FIG.3 and FIG.4, the operation control method of the said system A is demonstrated with reference also to FIG. 1, FIG.

  FIG. 3 is a control routine relating to the collection of information from each sensor of the system and the prediction of power demand and hot water supply demand for one day (24 hours).

  First, in step S101, the database 46 of the control unit 4 reads various information and temperature data from the temperature sensors T1 to T10, the flow sensors F1 and F2, the power sensor, and the timing unit 44 of the system A.

  In reading the information, for example, data is read every minute, and instantaneous demand (or average demand in a predetermined time span such as one hour) is recorded.

Here, the data for each day of the week and the temperature at a predetermined time for each day of the week may also be recorded and learned. If the learning period is continued for at least one week, it is possible to predict the day (specific day) by referring to the past data on the same day of the week as the prediction day (day of the week). In addition, it may be classified as weekday, Saturday, and Sunday instead of the day of the week (Sun, Mon, Tue, ... Sat).
That is, since the hot water supply demand increases or decreases on the same day of the week depending on the temperature, more accurate prediction can be made by selecting data close to the temperature of the day of the week in addition to the day of the week. Furthermore, if it is stored together with information on special days such as holidays and the year-end and New Year holidays, further accuracy can be expected.

Also, the bathing demand is determined by data from the heat source unit 3 (which can be determined by the status flag of the automatic bathing switch ON of the remote control not shown), etc. Prediction accuracy is improved by learning the generation time and the amount of heat used.

Proceeding to step S102, the demand prediction unit 41 of the control unit 4 starts from the past demand learning data stored in the database 46 for 24 hours (here, the start time is 3:00 am and the end time is 24 hours later the morning of the next day). 3 o'clock) power demand, hot water demand, and bathing time / demand.
And these demand prediction values are taken over by the control routine of FIG.

  The operation control after the demand prediction will be described with reference to FIGS. 1 and 2 based on FIG.

  First, in step S1, the demand prediction unit 41 of the control unit 4 monitors, for example, until 3 am, and if it is 3 am (YES in step S1), the process proceeds to step S2 and is predicted by the routine. From the demand, the demand up to 24 hours later is predicted and the time when the bathing occurs is predicted.

  In the next step S3, it is determined whether the bathing is performed within 24 hours from the predicted value of step S2, that is, whether the bathing is performed within 24 hours. The process proceeds to step S4. On the other hand, if bathing is not performed by taking a shower without taking a bath that day (NO in step S3), the process proceeds to step S5.

In step S4, the activation time determination unit 42 of the control unit 4 sets the bathing occurrence time predicted in step S2 as the stop time of the fuel cell 1, and proceeds to step S6. By setting the bathing occurrence time as the stop time of the fuel cell 1, the calculation process can be simplified. That is, once the bathing time is determined, the calculation amount is reduced by accompanying the calculation by shifting the start time of the fuel cell 1.
Further, in step S5, there is a case where the predicted value does not have a bath, so in this case, the peak predicted time of hot water supply demand is set as the stop time of the fuel cell 1 and the process proceeds to step S6.

In step S6, the fuel cell activation time is set as appropriate (for example, if the current time is 10 o'clock, it is shifted by 1 hour, 10:00, 11:00, 12:00,...), And in step S7, every hour. Each operation pattern is calculated with the bathing time determined in step S4 as the stop time with the startup time shifted and set, and one of the parameters of primary energy consumption, utility cost, and carbon dioxide emission is obtained. In a specific example, if the current time is 10:00 am, the activation time is set every hour until 18:00 am, 11:00 am, 12:00,...
In step S7, the start time (for example, 11:00) set from the current time and the power demand amount and hot water supply demand amount in the stop time period after the stoppage of power generation are integrated as the primary energy consumption amount for the stop time as follows. Ask.
(Electric power demand kWh / 0.36 (power plant efficiency)) + (Hot water supply demand kcal / 0.75 (Water heater efficiency) / 860)
Here, standby energy (power and gas) of the fuel cell system may be added.
The start-up time from start-up to power generation (eg, 1 hour) is ((power demand kWh + power kWh required for start-up) /0.36) + (hot-water supply demand kcal / 0.75) at each time during power generation. ) / 860 + (gas calorie required for startup kcal / 860)
Calculating with the start time.
During power generation, every time,
((Power demand amount kWh−power generation amount kWh (the rated power generation amount is equal to or greater than the rated power generation amount; for example, 1 kW) /0.36) + (power generation amount kWh / power generation efficiency) + (heat amount kcal / 0. 75/860)
Accumulate power generation time with.
Here, the amount of heat for the auxiliary heat source unit is the amount of heat stored in the tank (actually calculated from the measured temperature in the tank; the tank capacity is added to the difference between the average temperature in the tank and the water temperature)
The amount of exhaust heat recovered obtained by the amount of power generation kWh / power generation efficiency × exhaust heat efficiency is added to the tank heat storage amount at each time, and the amount of heat is subtracted when a hot water supply demand forecast is generated, resulting in a negative value.
By calculating the primary energy consumption at the time of stopping, starting, and power generation, and calculating the total for one day, the necessary primary energy consumption for one day can be calculated. In addition, the utility cost and carbon dioxide emission can be calculated based on the electric power and gas charges and the carbon dioxide emission intensity.

  In step S8, it is determined whether or not the absolute value of the value obtained by subtracting the start time from the stop time of the fuel cell is less than one hour. If it is less than one hour (YES in step S8), the process proceeds to step S10. move on. On the other hand, if it is 1 hour or more (NO in step S8), one more hour is added to the activation time previously calculated in step 9, and step S7 and subsequent steps are repeated again.

  In step S10, the fuel cell starting time that minimizes any of the parameters of primary energy consumption, utility costs, and carbon dioxide emission among all the operation patterns calculated in steps S7, S8, and S9 is selected. The value is set as the starting time of the fuel cell 1, and the process proceeds to step S11.

  In step S11, it is determined whether or not the activation time of the fuel cell 1 determined in step S10 has been reached. If the activation time has been reached (YES in step S11), the process proceeds to step S12. On the other hand, if the activation time has not been reached, it is determined in step S13 whether one hour has elapsed since the determined time.

If one hour has elapsed since the determination in step S11 (YES in step S13), the process returns to step S2, and step S2 and subsequent steps are repeated again. Such a loop (YES loop of S13) indicates that there may be a case where the calculation result differs from the predicted value of the heat storage amount at the previous calculation due to the latest measured heat storage amount in the hot water tank 2 (see FIG. 1). In consideration of this, if there is a difference between the predicted value of the amount of heat in the hot water tank 2 and the actual numerical value in such a case, step S2 and subsequent steps are repeated.
On the other hand, if one hour has not elapsed (NO in step S13), the process returns to step S11, and the loop in which step S11 is NO and step S13 is NO is repeated.

In step S12, the fuel cell 1, that is, the cogeneration system A is activated. In step S12 ′, it is determined whether one hour has elapsed after the activation. Then, the process proceeds to step S14, and the step is performed at regular time intervals, that is, at one hour intervals. The operation pattern is recalculated by the same method as S7 to S9. Calculate the power generation output and correct the power generation output.
Specifically, after the start of power generation, for example, the discount level of the power generation output value is calculated at intervals of one hour, and the parameter of any one of the minimum primary energy consumption, utility cost, and carbon dioxide emission among the combinations is calculated. Calculate and correct the output with the power generation output under the condition that the parameter is minimized. Here, the discount of the power generation output value is performed by reducing the output (for example, a predetermined ratio such as 90%, 80%, 70% of the necessary generated power) for the purpose of energy saving and by operating the exhaust heat recovery amount. This is performed to operate the fuel cell 1 for a long time by reducing the amount of heat stored in the tank.

In the next step S15, the first stop time of the fuel cell is provisionally set to the current time (automatically), and the stop time is sequentially determined based on each demand forecast for the next one day (24 hours) at one hour intervals. Any parameter of primary energy consumption, utility cost, and carbon dioxide emission for each combination is calculated (loop from step S16 to step S18).
Since it has already started, after the startup, the fuel cell startup time does not have to be shifted every hour.
In this embodiment, even the stop time of the fuel cell 1 has only to be shifted and compared for every hour, so that the amount of calculation processing can be reduced. When determining the stop time, calculation of multiple operation patterns when restarting after the shifted stop time (when restart time is set as the next bathing expected time and the restart time is shifted) Thus, the optimal stop time may be determined by adding and comparing any of the parameters of the primary energy consumption, the utility cost, and the carbon dioxide emission for a total of one day.

  When the fuel cell stop time is calculated by shifting a predetermined time (for example, 24 hours) from the current time (YES in step S17), the process proceeds to step S19, where the primary energy, from the combination of stop times obtained by the above calculation, The fuel cell stop time is determined by selecting the one with the smallest parameter of utility cost or carbon dioxide emission.

  In the next step S20, the control unit 4 determines whether or not the current time has reached the stop time of the fuel cell 1 determined in step S19, and if it is the stop time (YES in step S20). Proceed to step S21. On the other hand, if it is not yet the stop time (NO in step S20), the process proceeds to step S22.

In step S22, it is determined whether one hour has elapsed from the time determined in step S20 whether or not the current time is the fuel cell stop time. If one hour has elapsed (YES in step S22). ), Return to step S14, and repeat step S14 and subsequent steps. On the other hand, if 1 hour has not elapsed (NO in step S22), the process returns to step S20, and step S20 and subsequent steps are repeated.
In the case of YES in step S22, the steps after step S14 are repeated in order to correct the difference between the predicted heat storage amount and the actual heat storage amount when the usage of the hot water in the hot water tank 2 is different from the prediction. It is.
In other words, even if the operating situation is different from what is expected, it is possible to cope with any hot water supply load pattern with large variations by redetermining the power generation output and stop time (same start time) of the fuel cell in a flexible manner. It is.

  In step S21, the fuel cell 1 is stopped, and in the next step S23, the fuel cell is stopped and checked until one hour elapses (the same loop is repeated). If one hour has passed since the fuel cell was stopped (YES in step S23), the process proceeds to step S24.

  In step S24, it is determined whether or not the number of activations of the fuel cell per day is within a specified number (for example, once). If it is within one time (YES in step S24), the process proceeds to step S25. On the other hand, if it is the specified number of times (for example, twice) or more (NO in step S24), the process returns to step S1, and step S1 and subsequent steps are repeated. That is, if the fuel cell is repeatedly started and stopped many times, it may lead to deterioration of the system. Therefore, every time the fuel cell is newly started, the number of start times per day is determined and the control is started from the first step S1. Configured to start over.

  In step S25, the restart determination unit 45 of the control unit 4 determines the primary energy consumption, the utility cost, and the carbon dioxide emission until 24 hours after the fuel cell is stopped and restarted after one hour has elapsed. Calculate any parameter. Here, the stop time is shifted every specified time (for example, every hour), and the parameters (any parameter of the primary energy consumption, the utility cost, and the carbon dioxide emission) are obtained. In the next step S26, the parameter (any parameter of primary energy consumption, utility cost, carbon dioxide emission) up to 24 hours after the restart is calculated.

  In step S27, any of the parameters of the primary energy consumption, the utility cost, and the carbon dioxide emission when the restart time is shifted by shifting the stop time determined in step S25 is the case where the restart is not performed as determined in step S26. The primary energy consumption, utility costs, and carbon dioxide emissions are judged to be less than any of the parameters, and each primary energy consumption and utility costs when restarted. If any of the parameters of carbon dioxide emission is below the value of any of the parameters of primary energy consumption, utility costs, and carbon dioxide emission when not restarting (YES in step S27) If so, the process proceeds to step S28, the fuel cell 1 is restarted, and then the process proceeds to step S30.

  On the other hand, any of the parameters of primary energy consumption, utility costs, and carbon dioxide emissions for all patterns (combinations with shifted stop times) when restarting is a parameter for not restarting (primary energy) When the value of any one of the parameters of consumption, utility costs, and carbon dioxide emission) is exceeded (NO in step S27), the process proceeds to step S29, and the process proceeds to step S29 ′ without restarting the fuel cell. It is determined whether one hour has passed since the determination of the above and the current time is before 3:00 AM. If YES in step S27, it is determined in step S25 whether to restart again. On the other hand, if S27 is NO, the process directly returns to step S1, and step S1 and subsequent steps are repeated.

  In step S30, the stop time determination unit 43 of the control unit 4 temporarily sets the fuel cell stop time to the current time, and sets one of the parameters of primary energy consumption, utility cost, and carbon dioxide emission to each demand predicted value. Calculation is performed from (electric power, hot water supply, bathing) (step S31). Then, the primary energy consumption, the utility cost, the carbon dioxide are sequentially shifted by one hour (step S33), and the stop time is sequentially shifted by one hour from the current time until 24 hours have elapsed. Any parameter of the discharge amount is calculated from each demand prediction value (electric power, hot water supply, bathing) (step S31 to step S33 loop).

When the stop time of the fuel cell 1 is shifted from the current time by a predetermined time (for example, 24 hours) and the primary energy consumption is calculated (YES in step S32), the process proceeds to step S34, and the primary energy consumption is calculated by the above calculation. Select the parameter that minimizes the primary energy consumption, utility cost, or carbon dioxide emission parameter from each of the stop times at which the parameters for energy consumption or carbon dioxide emission were calculated. To determine the stop time of the fuel cell.
Then, it is determined whether or not the current time is the stop time determined in step S34 (step S35). When the determined stop time is reached (YES in step S35), the fuel cell is stopped (step S37). Return to step S1. If the determined stop time has not been reached (NO in step S35), it is determined whether one hour has elapsed from the determination time in step S34 while continuing operation (power generation) of the fuel cell (step S36). If one hour has elapsed from the determination time (YES in step S36), the process returns to step S30, and the routine for determining the stop time is repeated.

  The reason why the control is terminated at 3:00 am in step S1 of the control routine of FIG. 4 is that the recent lifestyle is often awake after bathing until midnight, and the system is judged one day. It depends on what is selected as the appropriate (largest common divisor) time (time to start control) as a delimiter. However, this is not limited to 3 am, and may be 2 am or 4 am.

  FIG. 5 is actual measurement data showing an example of operation of the system in the present embodiment. Among the recorded data, there are power demand (characteristic line W1), power generation output (characteristic line W2) hot water supply prediction value (characteristic line H1), and hot water supply demand (characteristic line H2).

According to the data shown in FIG. 5, the bathing time and the amount of heat are predicted, and the bathing time is set to T2.
In addition, the start time of the fuel cell is shifted backward every hour starting at 4 am, and calculation of any parameter of primary energy consumption, utility cost, carbon dioxide emission in each case is performed. ing. In addition, in order to cope with the case where the hot water in the hot water tank 2 has not decreased from the prediction, the value of the activation time is updated until the actual activation is recalculated at a predetermined interval. As a result, the activation time is determined at 3 pm (T1) in FIG.

  After start-up and power generation, power and hot water demand forecast values for the next day are obtained every hour, and in each operation pattern in which the stop time is shifted from the forecast values, primary energy consumption, utility costs, Any parameter of the carbon emission amount is calculated and compared to determine when to stop the fuel cell 1.

  Further, the power generation amount is reviewed (recalculated) every hour, and the fuel cell is stopped at the determined stop time T4.

In FIG. 5, points P1 and P2 in the predicted hot water supply value indicate points where a hot water supply load is generated (predicted) after the fuel cell operation is stopped.
In the example of the prior art operation control of FIG. 6, there is a demand (prediction) of the hot water supply load similar to Qx. However, in the prior art, driving is performed aiming at bathing, and the tank stops when the tank is full just before bathing. The demand for hot water supply Qx in the next morning is low because the amount of heat stored in the tank is small, and it is not possible to cope with this demand unless gas is burned with an auxiliary heat source machine to produce hot water. In the present invention, the hot water in the hot water storage tank , P1 and P2 can be dealt with. Actually, it can be seen that the hot water supply demand at the time indicated by the symbol H2 in FIG. 5 is covered by the hot water in the tank.

The control in steps S23 to S30 of the routine of FIG. 4 deals with a case where the prediction is greatly deviated and the system is restarted.
For example, unlike a normal life pattern, if the bathing is slow due to a sudden outing or the like, the pattern becomes different from the case where the operation pattern is calculated, the hot water tank 2 becomes full early, and the fuel cell 1 stops. . After that, when bathing is performed, there is room in the hot water storage tank and operation becomes possible.
In some cases, restarting the fuel cell 1 at that time may save energy than not starting the fuel cell until the next day.

From that point on, each of the cases where the engine is started and the stop time is shifted little by little is calculated, and an operation pattern that minimizes any of the parameters of primary energy consumption, utility cost, and carbon dioxide emission is selected. On the other hand, the parameter (any parameter of primary energy consumption, utility cost, carbon dioxide emission) when not restarting at that time is calculated. If the parameters (either primary energy consumption, utility costs, carbon dioxide emissions) are smaller when restarting by comparing the numerical values of the parameters in both, the startup time is This is determined as the start-up time of the fuel cell and is referred to as “restart”.
The control to be performed is the same as steps S10 to S13 and steps S15 to S19. Since it is sufficient to perform the same calculation, the calculation amount is small.

  In the simulation, the number of activations of the fuel cell is set to two or less. If the number of activations performed per day is increased, a burden is imposed on the entire fuel cell device. Therefore, it is assumed that the number of activations is not more than 3 times. However, it is not limited to “within 2 times”.

  Here, the determination as to whether or not to restart is performed, for example, after one hour has elapsed since the fuel cell stopped. If it is selected not to restart, whether or not to restart every hour until a predetermined time (for example, AM 3 o'clock) is determined by the same calculation.

  According to the embodiment of the present invention having the configuration and the control method described above, the predicted bathing time predicted by the demand prediction unit 41 of the control unit 4 or the time when the hot water supply demand is predicted to be at the peak is determined by the fuel cell 1. Since the start time is set to the stop time, the start time is changed one hour at a time, and the time at which any of the parameters of energy consumption, utility costs, and carbon dioxide emissions is minimized is determined as the start time. The required number of calculations is a value obtained by dividing the time from the prediction time (for example, 3:00 am) to the set stop time (for example, 18:00) by a predetermined time ((18:00 to 3:00) ) ÷ 1 hour = 15 times), the number of times is extremely small compared with the conventional method.

  Similarly, after the fuel cell generates electricity, the stop time of the fuel cell 1 is changed, for example, by one hour, and any one of the parameters of primary energy consumption, utility cost, and carbon dioxide emission is calculated. Since the stop time at which the (primary energy consumption amount, utility cost, carbon dioxide emission amount) is minimized is the stop time of the fuel cell 1, the number of calculations when determining the stop time is also started. After that, the time until stopping is divided by a predetermined one hour ((19: 00-9 o'clock) / one hour = 10 times), which is much smaller than the conventional method.

In the illustrated embodiment, since the demand pattern of each household can be learned and predicted by the demand prediction unit 41 of the control unit 4, control corresponding to the demand pattern of each household can be performed.
Therefore, it is possible to realize so-called “universal control” without selecting a user.

  In addition, after the start time of the fuel cell 1 is determined, for example, every hour, the process of re-correcting the start time of the fuel cell 1 is repeated. If, for example, the amount of heat stored in the hot water tank 2 in the cogeneration system A is different from the predicted transition, the optimal start-up time of the fuel cell 1 can be adjusted accordingly.

  In addition, since the fuel cell 1 is configured to repeat the process of determining the stop time of the fuel cell 1 every predetermined hour after the stop time of the fuel cell 1 is determined after the fuel cell 1 generates power, the power demand and the hot water supply demand Even when the demand is different from the predicted demand pattern, it can be dealt with by adjusting the stop time.

It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.
For example, in the illustrated embodiment, the fuel cell cogeneration system is described, but the present invention can be similarly applied to a gas engine cogeneration system.

The block diagram which showed the structure of the whole cogeneration system in embodiment of invention. The block diagram explaining the internal structure of the control unit of embodiment of this invention. The flowchart which showed the operation control flow of the system after reading various data in embodiment of this invention until it estimates electric power demand and hot water supply demand. The control flowchart which showed the flow of control after the demand prediction in embodiment of this invention. The actual measurement data at the time of a cogeneration system operation by an embodiment of the present invention. Measured data when operating a cogeneration system in the prior art.

Explanation of symbols

A ... Cogeneration system B ... Home (housing)
Lh ... Hot water supply line Lw ... Circulation line La ... Reheating line Lm, Ln ... Water supply line Lt, Ltf ... Signal line Sw ... Bath water level sensors F1, F2, F3 ... Flowmeters T1 to T10 ... Temperature sensor 1 ... Fuel cell 2 ... Hot water storage hot water tank 3 ... Heat source device 4 ... Control unit 5 ... Tub 5w ... Hot water supply for bath Port 6 ... Kitchen hot water supply port 10 ... Hot water supply system 40 ... Control panel 41 ... Demand prediction unit 42 ... Start time determination unit 43 ... Stop time determination unit 44 ... Timekeeping Unit 45... Restart determination unit 46... Database 47... Fuel cell control signal generation unit

Claims (8)

In the cogeneration system having the hot water generating means (1), the control means (40), and the hot water storage tank (2), the control means (40) is a demand prediction means (41) and the activation time of the hot water generating means (1). A start time determining means (42) for determining the stop time, a stop time determining means (43) for determining the stop time of the hot water generating means (1), and a time measuring means (44), and a control means (4) ) Temporarily set the bathing time predicted by the demand prediction means (41) or the peak time of hot water supply demand as the stop time of the hot water generation means (1), and the hot water generation means (1) Based on the demand predicted by the demand forecasting means (41) by appropriately setting the startup time, one of the parameters of energy consumption, utility cost, and carbon dioxide emission is calculated, and the calculated parameter is minimum. The start time is determined by the start time determining means (42) as the start time of the hot water generating means (1), the hot water generating means (1) is started at the start time, and the power generation output value is corrected after the start. While calculating the operation pattern, the stop time of the hot water generating means (1) is changed by a predetermined time after the current time to calculate any of the parameters of energy consumption, utility cost, and carbon dioxide emission, A cogeneration system having a function of selecting a stop time at which the calculated parameter is minimum and determining the stop time of the hot water generating means (1) by the stop time determining means (43). The start time determination means (42) sets the stop time of the hot water generation means (1) in the stop time determination means (43) and then reaches the start time of the hot water generation means (1) every predetermined time. The start time of the hot water generating means (1) is changed by a predetermined time with the set stop time as a fixed value, and any one of the parameters of energy consumption, utility cost, and carbon dioxide emission is calculated and calculated. The cogeneration system according to claim 1, wherein the cogeneration system is configured to repeat a process of selecting a starting time that minimizes the parameter and determining the starting time of the hot water generating means (1). The stop time determining means (43) changes the stop time of the hot water generating means (1) by a predetermined time every predetermined time until the stop time is reached after the stop time of the hot water generating means (1) is determined. A process of calculating one of the parameters of consumption, utility costs, and carbon dioxide emission, selecting a stop time at which the calculated parameter is minimum, and re-determining the stop time of the hot water generating means (1) is repeated. The cogeneration system according to claim 1, which is configured as described above. When a certain period of time has elapsed after the hot water generating means (1) is stopped, the energy consumption, the utility cost, and the carbon dioxide emission amount until the predetermined time elapses when the hot water generating means (1) is started at that time. Any parameter is calculated based on the demand predicted by the demand prediction means (41), and the parameter until the predetermined time elapses when the hot water generation means (1) is not started at that time is calculated as the demand prediction means ( 41) is calculated based on the demand predicted by 41), and both are compared, and when the warm water generating means (1) is started at that time, the determination is made to restart the hot water generating means (1) if the parameter is small. The cogeneration system according to any one of claims 1 to 3, further comprising restart determination means (45). In the control method of the cogeneration system (A) having the hot water generating means (1), the control means (40) and the hot water storage tank (2), the bathing time predicted by the demand prediction means (41) or the peak of hot water supply demand Is temporarily set as the stop time of the hot water generating means (1), the startup time of the hot water generating means (1) is set as appropriate, and the energy is calculated based on the demand predicted by the demand predicting means (41). A step of calculating any of the parameters of consumption, utility cost, and carbon dioxide emission, selecting a startup time that minimizes the calculated parameter, and determining the startup time of the hot water generating means (1) (S10) ), A step (S12) of starting the hot water generating means (1) at the start time, and calculating an operation pattern while correcting the power generation output value after the start of the hot water generating means (1), and the hot water generating means 1) Change the stop time in steps of the current time after the current time to calculate one of the parameters of energy consumption, utility costs, and carbon dioxide emissions, and select the stop time that minimizes the calculated parameter And a step (S19) of determining the stop time of the hot water generating means (1). After setting the stop time of the hot water generating means (1), until the start time of the hot water generating means (1) is reached, the start time of the hot water generating means is set at a fixed value for each predetermined time. The energy consumption amount, the utility cost, and the carbon dioxide emission amount are changed every predetermined time, and the activation time at which the calculated parameter is minimized is selected to activate the hot water generating means (1). The method of controlling a cogeneration system according to claim 5, wherein the process of determining as is repeated. After the stop time of the hot water generating means (1) is determined, until the stop time is reached, the stop time of the hot water generating means (1) is changed by a predetermined time every predetermined time, and energy consumption, utility costs, and carbon dioxide 7. The process according to claim 5, wherein any one of the parameters of the discharge amount is calculated, a stop time at which the calculated parameter is minimum is selected, and the process of redetermining the stop time of the hot water generating means (1) is repeated. A control method of the described cogeneration system. When a certain time has elapsed after the hot water generating means (1) is stopped, the energy consumption, the utility cost, and the carbon dioxide emission amount until the predetermined time elapses when the hot water generating means (1) is started at that time. Is calculated based on the demand predicted by the demand prediction means (41), and further, the parameter until the predetermined time elapses when the hot water generation means (1) is not started at that time is demand prediction. A step of calculating based on the demand predicted by the means (41), comparing the both, and restarting the hot water generating means (1) if the number of the parameters when the hot water generating means (1) is started at that time is small The cogeneration system control method according to any one of claims 5 to 7, comprising (S23 to S28).

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