JP2006214606A - Cogeneration system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cogeneration system and its operating method capable of properly suppressing the deterioration of energy-saving due to extra heat by properly lowering the output of a cogeneration device at such a timing that extra heat is predicted. <P>SOLUTION: When the operating efficiency of an operation control means in the partial output of the cogeneration device is higher than an operating efficiency when an mainly electrical operation control is performed, an operation control means performs, as an output lowering operation, a partial output operation for setting the output of the cogeneration device to a partial output. When the operating efficiency in the partial output of the cogeneration device is equal to or lower than the operating efficiency when the mainly electrical operation control is performed, the operation control means performs, as the output lowering operation, a suppressing mainly electrical output operation for setting the output of the cogeneration device to a suppressing mainly electrical output smaller by a prescribed suppressing width than a power load. Also, in suppressing mainly electrical output operation, the suppressing width is calculated by a surplus power lead-out means or adjusted based on a measured surplus power. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a combined heat and power device that generates heat and electric power, a hot water storage tank that collects heat generated by the combined heat and power device and stores it as hot water, and the combined heat and power device when the combined heat and power device is in operation. The present invention relates to a cogeneration system provided with operation control means for executing main operation control for causing a set output to follow a power load, and an operation method thereof.

In such a cogeneration system, a combined heat and power supply device such as an engine-driven generator and a fuel cell is provided, and the generated power of the combined heat and power supply device is supplied to a power consuming unit such as an electric device, and the generated heat of the combined heat and power device is, for example, The hot water heated by the heat is temporarily stored in a hot water storage tank and supplied to a heat consuming unit such as a hot water supply unit or a heating device.
And by providing such a cogeneration system in each home, etc., at least part of the power consumed in that home can be supplemented with the power generated by the combined heat and power supply device, so that the power received from the commercial power source is reduced. Moreover, since the heat generated at that time can be used as hot water, it is effective in terms of energy saving and economical efficiency.

  In such a cogeneration system, for example, the operation control means makes it possible to follow the power load in the power consumption unit with the set output of the combined heat and power unit in a relatively short output adjustment period such as several minutes (for example, one minute). May be configured to perform main operational control.

  In a cogeneration system that performs main operation control, the current power load can be covered by generated power by executing the main operation control, but it does not support the current heat load that is currently required. However, a surplus heat state in which heat remains with respect to the current heat load may occur, and the energy saving performance may deteriorate.

Therefore, when it is predicted that the heat load will be relatively small with respect to the amount of heat generated by the combined heat and power unit when the main operation control is performed, the operation control means will output the output of the combined heat and power unit. In some cases, the heat surplus state is suppressed by reducing the heat generation of the combined heat and power supply device (see, for example, Patent Document 1).
In addition, as a form of reducing the output of the combined heat and power device when a surplus heat state is predicted as described above, the output of the combined heat and power device is set to a partial output such as a minimum output, or the output of the combined heat and power device Is set to a suppressed main output smaller than the power load by a predetermined suppression width.

In a cogeneration system that performs electric main operation control, the output of the combined heat and power supply device cannot follow the sudden decrease in the power load sensitively, and the generated power of the combined heat and power supply device exceeds the power load. There is a case where surplus power that is a surplus with respect to the power load of the generated power of the co-feeding device is generated.
And this surplus electric power can be converted into heat stored in the hot water storage tank by an electric heater and used effectively.

JP 2004-286008 A

  In the cogeneration system, when a heat surplus state is predicted, the configuration in which the output of the cogeneration device is set to partial output as described above, the generated heat of the cogeneration device is greatly reduced. The state can be surely canceled, and the deterioration of energy saving due to the excessive heat state can be greatly suppressed. However, when the operation efficiency at the partial output of the combined heat and power device is low, there is a concern about the deterioration of energy saving due to setting the output of the combined heat and power device to a partial output with low operation efficiency. Furthermore, the combined heat and power device Unlike the prediction, a heat shortage state with a relatively large heat load is likely to occur, which is unlikely to be predicted. There is concern about the deterioration.

  On the other hand, in the cogeneration system, when a surplus heat state is predicted, in the configuration in which the output of the combined heat and power device is set to the suppressed main output as described above, the decrease in the generated heat of the combined heat and power device is small. Unlike the prediction, it becomes difficult to generate a heat shortage state for a heat load that is actually relatively large, and it is possible to suppress deterioration of energy saving due to the heat shortage state. However, by setting the output of the combined heat and power device to a relatively large suppressed power output, the reduction in the heat generated by the combined heat and power device is small, so the excess heat state cannot be resolved and the excess heat state is saved. It is not possible to suppress much of the deterioration of energy.

  The present invention has been made in view of the above problems, and its purpose is to save energy associated with the excess heat state by appropriately reducing the output of the combined heat and power device at the time when the excess heat state is predicted. It is in the point of providing the cogeneration which can suppress sexual deterioration appropriately.

In order to achieve the above object, a cogeneration system operating method according to the present invention includes a cogeneration device that generates heat and electric power together, and a hot water storage that collects the heat generated by the cogeneration device and stores it as hot water. An operation method of a cogeneration system provided with a tank and an operation control means for executing an electric main operation control for following a power load with a set output of the combined heat and power device when the combined heat and power device is operated, A characteristic configuration is a time when occurrence of a surplus heat state is predicted or a time when a surplus heat state occurs when it is assumed that the operation control unit has executed the main operation control for a predicted power load. It is configured to execute an output reduction operation for reducing the output of the fuel cell at a certain heat surplus handling period,
When the operation efficiency at the partial output of the combined heat and power device is higher than the operation efficiency when the main operation control is executed, the output of the combined heat and power device is partially output to the operation control means as the output reduction operation. The partial output operation set to the output is executed, and the operation efficiency at the partial output of the cogeneration device is lower than or equivalent to the operation efficiency when the electric main operation control is executed. In the case where the output is reduced, the output of the combined heat and power unit is reduced by a predetermined amount of suppression than the power load. It is in the point which performs the suppression electric main output driving | operation set to the main output.

  A cogeneration system according to the present invention for achieving the above object includes a combined heat and power device that generates heat and electric power, a hot water storage tank that collects the heat generated by the combined heat and power device and stores it as hot water, The cogeneration system is provided with operation control means for executing electric main operation control for causing the set output of the cogeneration device to follow a power load during operation of the cogeneration device, and the first characteristic configuration thereof is: When the operation control means assumes that the main operation control has been executed for the predicted power load, the heat surplus countermeasure is the time when the occurrence of the heat surplus state is predicted or the time when the heat surplus state occurs. When the output reduction operation for reducing the output of the fuel cell is executed at the time, and the operation efficiency at the partial output of the combined heat and power supply apparatus executes the main operation control If the operation efficiency is higher than the operation efficiency, the partial output operation is performed to set the output of the combined heat and power device to a partial output as the output reduction operation, and the operation efficiency at the partial output of the combined heat and power supply device is the main operation. When the operation efficiency is lower or equivalent to the operation efficiency when the control is executed, the output of the combined heat and power supply device is set to a suppressed main output that is smaller than the power load by a predetermined suppression width as the output reduction operation. It is in the point which performs the suppression electric main output driving | operation.

  That is, according to the characteristic configuration of the operation method of the cogeneration system and the first characteristic configuration of the cogeneration system, it is assumed that the main operation control is performed on the predicted power load predicted from the past power load. In such a case, the time when the occurrence of a heat surplus state is predicted for the predicted heat load predicted from the past heat load in the future, or the time when the heat surplus state is generated for the current current heat load. Since the operation control means executes the output reduction operation and reduces the output of the combined heat and power supply device at the time of coping with excess heat, the excess heat state can be suppressed.

Further, when the operation efficiency at the partial output of the combined heat and power device is higher than the operation efficiency when the main operation control is executed, the operation control means sets the output of the combined heat and power device to the partial output. Judging that the energy saving performance will not deteriorate so much, the partial output operation that sets the output of the combined heat and power unit to the partial output is executed as the above output reduction operation, and the generated heat of the combined heat and power unit is suppressed to the minimum. In addition, it is possible to efficiently and surely suppress the excess heat state, and to significantly suppress the deterioration of energy saving due to the excess heat state.
On the other hand, when the operation efficiency at the partial output of the combined heat and power device is smaller than the operation efficiency when the electric main operation control is executed, the operation control means sets the output of the combined heat and power device to the partial output. It is judged that energy saving is deteriorated, and the suppression power main that follows the power load in the form of setting the suppressed power output that is slightly smaller than the power load as the power reduction operation rather than the partial power operation. Execute the output operation, suppress the generated heat of the combined heat and power unit and the surplus power converted into heat by the electric heater, suppress the deterioration of energy saving due to the excess heat state, Can suppress the occurrence of a heat shortage state with respect to a relatively large heat load, and can also suppress the deterioration of energy saving due to such a heat shortage state.
The partial output can be set, for example, as a minimum output or an output that exhibits the highest operating efficiency among the outputs lower than the power load, while the suppressed power output is the power load. On the other hand, it can be set as an output that is smaller by a suppression width that is set to such an extent that it is possible to suppress the generation of excess heat and surplus power.

The second characteristic configuration of the cogeneration system according to the present invention is an electric heater that converts surplus power that is a surplus with respect to the power load of the generated power of the cogeneration apparatus into heat that is stored in the hot water storage tank,
Surplus power deriving means for calculating or measuring the surplus power,
In the suppression power main output operation in which the operation control means sets the output of the cogeneration device to a suppressed power main output that is smaller than the power load by a predetermined suppression width, the suppression width is calculated by the surplus power deriving means or The adjustment is based on the measured surplus power.

  That is, according to the second characteristic configuration of the cogeneration system, the surplus power deriving means calculates or measures the surplus power supplied to the electric heater, and the operation control means slightly suppresses the power load. In the case of executing the suppressed main output operation that follows the power load in the form of setting the suppressed main output as small as the width, the suppression width is adjusted based on the surplus power calculated or measured by the surplus power deriving means. By supplementing as much of the power load as possible with the power generated by the combined heat and power unit, the surplus power converted into heat by the electric heater can be reduced as much as possible to further suppress the occurrence of the excess heat state, As a result, it is possible to further suppress the deterioration of energy saving due to the excess heat state.

  According to a third characteristic configuration of the cogeneration system according to the present invention, the operation control unit calculates an average value or an integrated value of the surplus power calculated or measured by the surplus power deriving unit, and the suppression width is set to the average value. Or it is in the point set according to an integrated value.

  That is, according to the third characteristic configuration of the cogeneration system, the operation control means adjusts the suppression width based on the calculation or measurement result of the surplus power deriving means in the suppressed power main output operation. By setting according to the average value or integrated value of surplus power that fluctuates relatively slowly, not the instantaneous value of surplus power that fluctuates frequently, the output of the combined heat and power supply device becomes relatively stable, It is possible to suppress damage to the combined heat and power supply apparatus and a decrease in efficiency due to various fluctuations. In addition, as the average value or integrated value, a moving average value or moving integrated value that is repeatedly calculated while shifting the period, an average value by period or an integrated value by period that is calculated every predetermined period such as every day, etc. Can be used.

  The 4th characteristic structure of the cogeneration system which concerns on this invention sets the upper limit of the suppression width | variety on the conditions that a heat shortage state is not estimated when it is assumed that the said operation control means performed the said suppression electric main output driving | operation. In the point.

  That is, according to the fourth characteristic configuration of the cogeneration system, the operation control unit adjusts the suppression width based on the calculation or measurement result of the surplus power deriving unit in the suppression power main output operation. The upper limit value of the suppression width is set in such a way that a heat shortage state is not predicted when the operation is performed, in other words, a suppression power that is not predicted to have a heat shortage when it is assumed that the suppression main output operation is performed. When the suppression width for the lowest limit of the main output range is determined as the upper limit value and the suppression width is limited to be equal to or lower than the upper limit value, when performing the suppression power main output operation for avoiding the excess heat state, Occurrence of a heat shortage state after the time when the excess heat state is predicted can be suppressed, and as a result, deterioration of energy saving can be avoided.

A cogeneration system according to the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the cogeneration system recovers the fuel cell 1 as a combined heat and power generation device that generates electric power and heat, and the heat generated by the fuel cell 1 with cooling water. A hot water storage unit 4 for storing hot water in the hot water tank 2 and supplying a heat medium to the heat consuming terminal 3 using the cooling water, and an operation control unit as operation control means for controlling the operation of the fuel cell 1 and the hot water storage unit 4. 5 or the like.

The output of the fuel cell 1 is adjustable, and an inverter 6 for system linkage is provided on the power output side of the fuel cell 1, and the inverter 6 uses the generated power of the fuel cell 1 for commercial use. It is configured to have the same voltage and the same frequency as the received power received from the power supply 7.
The commercial power source 7 is, for example, a single-phase three-wire system 100/200 V, and is electrically connected to a power load 9 such as a television, a refrigerator, or a washing machine via a received power supply line 8.
The inverter 6 is electrically connected to the received power supply line 8 via the generated power supply line 10, and the generated power from the fuel cell 1 is supplied to the power load 9 via the inverter 6 and the generated power supply line 10. Is configured to do.

The received power supply line 8 is provided with power load measuring means 11 for measuring the load power of the power load 9, and this power load measuring means 11 is a so-called so-called current flowing to the commercial power supply 7 side in the received power supply line 8. It is also configured to detect whether or not a reverse power flow occurs.
The electric power supplied from the fuel cell 1 to the received power supply line 8 is controlled by the inverter 6 so that a reverse power flow does not occur, and the surplus power of the generated power is recovered by replacing the surplus power with heat. 12 is configured to be supplied.

The electric heater 12 is composed of a plurality of electric heaters, and is provided so as to heat the cooling water of the fuel cell 1 flowing through the cooling water circulation path 13 by the operation of the cooling water circulation pump 15, and is connected to the output side of the inverter 6. ON / OFF is switched by the actuated switch 14.
The operation switch 14 is configured to adjust the power consumption of the electric heater 12 according to the amount of surplus power so that the power consumption of the electric heater 12 increases as the amount of surplus power increases. Yes.
The surplus power can be calculated as a power value obtained by subtracting the power load measured by the power load measuring means 11 from the generated power of the fuel cell 1 measured as the output of the inverter 6. The measuring means 11 and the inverter 6 also function as surplus power deriving means X for calculating or measuring surplus power.
Incidentally, the surplus power is calculated as described above, and ON / OFF is switched by the operation switch 14 so that the power consumption of the electric heater 12 becomes equal to or greater than the surplus power. The amount of power obtained by drawing the generated power of the fuel cell 1 from the power load and adding the power consumed by the electric heater 12 is covered by the received power received from the commercial power source 7. This surplus power may be calculated or measured by another method, for example, by providing surplus power measuring means capable of measuring the power supplied to the electric heater 12 as surplus power.

  The hot water storage unit 4 supplies hot water for hot water through a hot water tank 2 for storing hot water in a state where temperature stratification is formed, a hot water circulation pump 17 for circulating hot water in the hot water tank 2 through the hot water circulation path 16, and a heat source circulation path 20. A heat source circulation pump 21 to be circulated, a heat medium circulation pump 23 to circulate and supply the heat medium to the heat consuming terminal 3 through the heat medium circulation path 22, a hot water storage heat exchanger 24 to heat the hot water flowing through the hot water circulation path 16, The heat source heat exchanger 25 for heating the hot water for heat source flowing through the heat source circulation path 20, the heat exchanger for heat medium heating 26 for heating the heat medium flowing through the heat medium circulation path 22, and the fan 27 are operated. In this state, an auxiliary heating heat exchanger 29 for heating the hot water taken out from the hot water storage tank 2 by the combustion of the burner 28 and the heat source hot water flowing through the heat source circulation path 20 is provided.

The hot water circulation path 16 is branched and connected so that a part thereof is in parallel, a three-way valve 18 is provided at the connection location, and a radiator 19 is provided in the branched flow path. Yes.
Then, by switching the three-way valve 18, the hot water taken out from the lower part of the hot water tank 2 is circulated so as to pass through the radiator 19, and the hot water taken out from the lower part of the hot water tank 2 is circulated so as to bypass the radiator 19. It is comprised so that it may switch to the state to be made to.

The hot water storage heat exchanger 24 is configured to heat the hot water flowing through the hot water circulation path 16 by passing the cooling water of the cooling water circulation path 13 that has recovered the heat output from the fuel cell 1. Has been.
In the heat source heat exchanger 25, the hot water for the heat source flowing through the heat source circulation path 20 is heated by flowing the cooling water in the cooling water circulation path 13 that has recovered the heat generated by the fuel cell 1. It is configured.
The auxiliary heating means M includes a fan 27, a burner 28, and an auxiliary heating heat exchanger 29.
Further, the heat source circulation path 20 is provided with a heat source intermittent valve 40 for intermittently flowing the heat source hot water.

The cooling water circulation path 13 is branched into a hot water storage heat exchanger 24 side and a heat source heat exchanger 25 side, and the flow rate of the cooling water to be passed to the hot water storage heat exchanger 24 side and the heat source use are branched at the branch points. A diversion valve 30 is provided for adjusting the ratio of the flow rate of the cooling water to be passed to the heat exchanger 25 side.
The diverter valve 30 allows the entire amount of cooling water in the cooling water circulation path 13 to flow to the hot water storage heat exchanger 24 side, or allows the entire amount of cooling water in the cooling water circulation path 13 to flow to the heat source heat exchanger 25 side. It is comprised so that it can also be made.

In the heat exchanger for heat medium heating 26, the hot water for the heat source heated by the heat exchanger for heat source 25 and the heat exchanger for auxiliary heating 29 is allowed to flow, thereby flowing through the heat medium circulation path 22. The heating medium is configured to be heated.
The said heat consumption terminal 3 is comprised by heating terminals, such as a floor heating apparatus and a bathroom heating apparatus.

  Further, a hot water supply load measuring means 31 for measuring the hot water supply heat load when supplying hot water taken out from the hot water tank 2 is provided, and a terminal thermal load measuring means 32 for measuring the terminal heat load at the heat consuming terminal 3 is also provided. ing.

  The operation control unit 5 controls the operation of the fuel cell 1 and the operation state of the cooling water circulation pump 15 while operating the cooling water circulation pump 15 during the operation of the fuel cell 1, as well as the hot water circulation pump 17 and the heat source. By controlling the operating state of the circulation pump 21 and the heat medium circulation pump 23, a hot water storage operation for storing hot water in the hot water storage tank 2 and a heat medium supply operation for supplying the heat medium to the heat consuming terminal 3 are performed. Has been.

By the way, when hot water is supplied, the hot water taken out from the hot water tank 2 with the heat source intermittent valve 40 closed is configured to supply hot water, and the hot water taken out from the hot water tank 2 is heated by the auxiliary heating means M, Water is mixed with hot water taken out from the hot water storage tank 2, and hot water at a hot water supply set temperature set by a remote controller (not shown) is supplied.
Therefore, in the hot water storage tank 2, hot water is stored within the capacity of the hot water storage tank 2 by subtracting the hot water extracted for hot water supply from the hot water added according to the output of the fuel cell 1. become.

First, the operation control of the fuel cell 1 by the operation control unit 5 will be described.
The operation control unit 5 executes main operation control for setting the output of the fuel cell 1 to the main output that follows the current power load currently requested when the fuel cell 1 is in operation.

Specifically, the operation control unit 5 obtains the current power load for each relatively short predetermined output adjustment period such as one minute in the main operation control, and from the minimum output (for example, 250 W) to the maximum output (for example, 1000 W). 3), the main output following the current power load is continuously determined as shown in FIG. 3A, and the output of the fuel cell 1 is set to the determined main output.
The minimum output may be set to 0 W or an extremely small output close to it within an allowable range.

  The current power load is obtained based on the measured value of the power load measuring means 11, and the current power load is obtained as an average value of the power load in the previous output adjustment period. Further, the current power load may be determined to be smaller by a predetermined margin than the actual power load.

In the electric main operation control as described above, there is a slight time delay from when the operation control unit 5 measures the current power load until the output of the fuel cell 1 is set to the electric main output.
That is, as shown in FIG. 3B, the actual generated power of the fuel cell 1 changes slightly with respect to the change state of the current power load. Then, the generated power of the fuel cell 1 cannot sensitively follow the sudden decrease in the current power load, the generated power of the fuel cell 1 exceeds the current power load, and surplus power is generated. Electric power is supplied to the electric heater 12 described above.

  Further, in the above main operation control, the operation control unit 5 reduces the surplus power, suppresses the heat generated by the electric heater 12, and suppresses the generation of the excess heat state. It is comprised so that driving | running | working may be performed. Hereinafter, this electric power output operation will be described.

  Incidentally, the excess heat state means, for example, that hot water stored in the hot water tank 2 is full and the radiator 19 is operated, or the heat output from the fuel cell 1 during the heat medium supply operation is consumed. It is larger than the terminal heat load and hot water supply load required at the terminal 3, the hot water stored in the hot water tank 2 is full, and the radiator 19 is in operation.

(Main output operation)
In the main output operation, the operation control unit 5 is configured to set the output of the fuel cell 1 to a main output that is smaller than the current power load by a certain amount or percentage.
That is, as shown in FIG. 4 (a), in the main output operation, the main output that is smaller by a certain amount from the current power load within the range from the minimum output to the maximum output is determined, and the output of the fuel cell 1 is changed to the main output. Set to the determined main output.
In other words, if the output that is smaller by a certain amount from the current power load is within the range from the minimum output to the maximum output, that output becomes the main output, and the output that is smaller by a certain amount from the current power load is larger than the maximum output. In such a case, the maximum output is determined as the main output, and when the output smaller than the current power load by a certain width is smaller than the minimum output, the minimum output is determined as the main output.

  Then, even when the actual power output of the fuel cell 1 changes slightly with respect to the change state of the current power load, as shown in FIG. Surplus power can be suppressed.

  In the main operation control, the main output is set as a smaller output than the main output set to follow the current power load within the range from the minimum output to the maximum output. be able to. Also, in this case, in order to prevent the main output from becoming less than the minimum output, when the output smaller than the predetermined width from the main output is smaller than the minimum output, the minimum output is determined as the main output.

  And the operation control part 5 is the time when generation | occurrence | production of a surplus heat state is estimated when it assumes that the said main operation control was performed with respect to the prediction electric power load, or the time when the surplus heat state has generate | occur | produced. It is configured to execute an output reduction operation for reducing the output of the fuel cell 1 at the excessive timing. Hereinafter, the output reduction operation will be described.

  The operation control unit 5 is configured to be able to execute the following partial output operation or suppressed main output operation as the output reduction operation.

(Partial output operation)
The operation control unit 5 is configured to set the output of the fuel cell 1 to a partial output in the partial output operation. And the surplus electric power mentioned above can be suppressed significantly by performing this partial output driving | operation.
The partial output can be set as a minimum output or an output that exhibits the highest operating efficiency among the outputs lower than the power load.

(Suppressed main output operation)
The operation control unit 5 is configured to set the output of the fuel cell 1 to a suppressed power output that is smaller than the current power load by a predetermined amount or ratio in the suppressed power main output operation. . Therefore, even when the actual generated power of the fuel cell 1 changes slightly with respect to the change state of the current power load, surplus power can be suppressed.
In addition, the suppression width | variety with respect to the present electric power load of the output of the fuel cell 1 in this suppression electric main output driving | operation is set larger than the fall width | variety (constant width) with respect to the present electric power load of the output of the fuel cell 1 mentioned above. Is done.

  Furthermore, the operation control unit 5 uses the surplus power that is calculated or measured by the surplus power deriving means X to reduce the suppression width, which is a width that reduces the output of the fuel cell 1 with respect to the current power load. Can be configured to adjust based on

  That is, as shown in FIG. 6, the operation control unit 5 first calculates or measures the surplus power Eo by the surplus power deriving means X in the suppressed power main output operation, and the current surplus power Eo and the past constant. The moving average value Ave (Eo) of the surplus power Eo is calculated from the surplus power Eo of the period (step # 2).

Next, it is determined whether or not the moving average value Ave (Eo) of the surplus power Eo is larger than a predetermined upper limit value e1 (for example, 50 W) (step # 3).
When the moving average value Ave (Eo) of the surplus power Eo is equal to or less than a predetermined upper limit value e1 (for example, 50 W), the suppression width Ed is set to the moving average value Ave (Eo).
Thus, in the suppression power main output operation, by setting the suppression width Ed to the moving average value Ave (Eo) of the surplus power calculated or measured by the surplus power deriving means X, the generated power of the fuel cell 1 can be reduced. While making it as large as possible, the surplus power converted into heat by the electric heater 12 can be reduced as much as possible.
The suppression width Ed may be set not to the moving average value Ave (Eo) but to, for example, the surplus power Eo that is an instantaneous value.

On the other hand, when the moving average value Ave (Eo) of the surplus power Eo is larger than a predetermined upper limit value e1 (for example, 50 W), the deterioration of energy saving due to an excessive increase in the received power from the commercial power supply 7 is suppressed. Therefore, the suppression width Ed is set to the upper limit e1 (step # 4).
Note that step # 3 and step # 4 may be omitted, and the suppression width Ed may always be set to the moving average value Ave (Eo). Moreover, you may adjust a suppression width | variety according to the average value according to a period calculated as an average value of the surplus electric power for every predetermined periods, such as every day, instead of the above-mentioned moving average value. In addition, instead of the above moving average value, the amount of suppression is adjusted according to the cumulative integrated value of surplus power for a certain period in the past and the integrated value by period calculated as the integrated value of surplus power for each predetermined period such as every day. It doesn't matter.

  Furthermore, the operation control unit 5 can set the upper limit value e1 of the suppression width Ed in a form in which a heat shortage state to be described later is not predicted when it is assumed that the suppression power main output operation is executed.

  Note that the heat shortage state means, for example, that the hot water stored in the hot water tank 2 is empty and the auxiliary heating means M is operated, or the heat output from the fuel cell 1 during the heating medium supply operation. The hot water stored in the hot water tank 2 is smaller than the terminal heat load and hot water supply load required by the heat consuming terminal 3, and the auxiliary heating means M is activated. Then, for example, as shown in FIG. 5, when it is assumed that the predicted power load and the predicted heat load in the determination target period such as one day are obtained and the suppressed power main output operation is executed for the predicted power load, the fuel cell It can be determined whether or not a heat shortage state occurs in which the generated heat of 1 is insufficient with respect to the predicted heat load.

In other words, by determining whether or not the above heat shortage state occurs while changing the suppressed main output, it is possible to prevent the heat shortage from being predicted when it is assumed that the suppressed main output operation has been executed. The main output range can be obtained, and the suppression range for the current power load at the lowest limit of the suppression main output range is determined as the upper limit e1.
And by restrict | limiting so that the suppression width | variety Ed may become the upper limit e1 or less, generation | occurrence | production of the heat shortage state by performing suppression electric main output driving | operation can be suppressed, As a result, deterioration of energy-saving property is reduced. It can be avoided.

  Furthermore, as shown in FIG. 7, the operation control unit 5 determines whether or not it is a heat surplus countermeasure timing described later (step # 11). Or it is comprised so that one output fall operation may be performed among the suppression electric main output operations (step # 12).

Next, description will be added regarding the determination of the excess heat handling time in step # 11.
For example, as illustrated in FIG. 5, the operation control unit 5 obtains a predicted power load and a predicted heat load in a determination target period such as one day, and assumes that the main operation control is performed on the predicted power load. In this case, it is determined whether or not a surplus heat state is generated in which the generated heat of the fuel cell 1 is excessive with respect to the predicted heat load, and the occurrence of the surplus heat state is predicted in a time zone before the surplus heat state occurs. Ask as a time.
In addition, the operation control unit 5 integrates the amount of heat released when the radiator 19 is activated to start heat dissipation, or the time when the integrated value is equal to or greater than the set value causes a heat surplus state. Ask as the time when.
And the time when generation | occurrence | production of the above heat surplus state is estimated or the time when the heat surplus state has generate | occur | produced is determined as the said heat surplus handling time.

  Further, the operation control unit 5 determines whether to execute the partial output operation or the suppressed main output operation as the output reduction operation based on the operation efficiency at the partial output of the fuel cell 1. It is configured.

That is, as shown in FIG. 8, is the operation efficiency A at the partial output of the fuel cell 1 higher than the operation efficiency when the main operation control is executed (that is, the operation efficiency at the main output of the fuel cell 1) a1? It is determined whether or not (step # 21).
When the operation efficiency A at the partial output of the fuel cell 1 is higher than the operation efficiency a1 when the main operation control is executed, the energy saving is not much by setting the output of the fuel cell 1 to the partial output. Judging that it does not deteriorate, the operation control unit 5 is caused to execute the partial output operation as the output reduction operation (step # 22).
On the other hand, when the operation efficiency A at the partial output of the fuel cell 1 is lower than or equal to the operation efficiency a1 when the main operation control is executed, the output of the combined heat and power supply device is set to the partial output. It is determined that the energy is deteriorated, and the operation control unit 5 is caused to perform the suppressed power main output operation as the output reduction operation (step # 23).

  The operating efficiency A and a1 are the following power generation merits that are merits of supplementing the power supplied to the power load 9 with the power generated by the fuel cell 1 rather than the power received from the commercial power supply 7. It can be obtained by the equation shown in 1.

[Equation 1]
Operation efficiency (power generation merit) = output of fuel cell 1 × (1 / power generation efficiency of commercial power source 7−1 / power generation efficiency of fuel cell 1)

  The operation control unit 5 itself may determine whether or not the operation efficiency A at the partial output of the fuel cell 1 in step # 21 is higher than the operation efficiency a1 when the main operation control is executed. However, separately, a cogeneration system designer or user determines that the operation control unit 5 is configured to execute the partial output operation as the output reduction operation, or the suppressed main output operation is performed. It may be determined whether to configure to execute.

  When the operation control unit 5 executes the determination in step # 21, the operation efficiency A at the partial output is calculated from the fuel consumption, generated power, and generated heat at the past partial output of the fuel cell 1. It can be configured to be calculated and updated at any time. With this configuration, whether the partial output operation is executed as an output reduction operation in accordance with a change in the state of the fuel cell 1 over time. It is possible to switch whether to execute the suppressed power main output operation.

  When the partial output is set to the minimum output, only the operation efficiency A at the minimum output can be updated at any time. On the other hand, when the partial output is an output that exhibits the highest operation efficiency among the outputs lower than the power load, the operation efficiency at each output of the fuel cell 1 that may be set as the partial output. A can be configured to update at any time as described above.

The time series power load and the time series heat load are managed by the operation control unit 5 as shown below.
That is, the operation control unit 5 uses, for example, a heat load as a hot water supply heat load and a terminal heat load, and converts each of an actual power load per unit time, an actual hot water supply heat load, and an actual terminal heat load into the power load measuring unit 11. And the output value of the inverter 6, the hot water supply thermal load measuring means 31, and the terminal thermal load measuring means 32.
And the operation control part 5 memorize | stores the value measured in the output value of the electric power load measurement means 11 and the inverter 6, the hot water supply heat load measurement means 31, and the terminal thermal load measurement means 32, and is time-sequentially. Power load and time-series heat load are managed every unit time such as one hour.
In addition, when the operation control unit 5 updates the time-series power load and the time-series heat load according to the actual use situation, the output values of the power load measuring means 11 and the inverter 6, the hot water supply heat load, The value measured by the measuring means 31 and the terminal thermal load measuring means 32 and the value already stored are added together at a predetermined ratio, and the added value is stored.

  Hereinafter, first to third examples will be described as examples of the determination of the partial output operation and the suppressed power main output operation based on the operation efficiency in the heat surplus handling timing and the setting method of the partial output in the partial output operation.

[First embodiment]
As the first embodiment, it is assumed that the operation efficiency at each output of the fuel cell 1 obtained as the power generation merit obtained by the equation shown in Equation 1 described above increases as the output increases as shown in Table 1 below. The embodiment will be described. In the equation shown in the above equation 1, the power generation efficiency of the commercial power source 7 is 0.366.

  When the main output following the current power load is 1000 W, 750 W or 500 W, the operation efficiency of the partial output smaller than the main output of the fuel cell 1 is the main output of the fuel cell 1. Since it is lower than the operation efficiency, the operation control unit 5 does not perform partial output operation in which the output of the fuel cell 1 is set to partial output as output reduction operation, but the output of the fuel cell 1 is less than the main output of the main output. Suppressed main output operation that is set to a small suppressed main output is executed.

[Second Embodiment]
As a second embodiment, it is assumed that the operation efficiency at each output of the fuel cell 1 obtained as the power generation merit obtained by the equation shown in the above equation 1 becomes lower as the output becomes larger as shown in Table 2 below. The embodiment will be described. In the equation shown in the above equation 1, the power generation efficiency of the commercial power source 7 is 0.366.

  When the main output following the current power load is 1000 W, 750 W, or 500 W, the operation efficiency of the partial output (300 W) of the fuel cell 1 smaller than the main output of the fuel cell 1 is Since it is higher than the operation efficiency at the main output, the output of the fuel cell 1 is not the suppressed power main output operation in which the output of the fuel cell 1 is set to the suppressed power output that is smaller than the main output by the suppression width. The partial output operation set to 300 W) is executed.

[Third embodiment]
As the third embodiment, the operation efficiency at each output of the fuel cell 1 obtained as the power generation merit obtained by the equation shown in the above equation 1 is maximum when the output is 750 W as shown in Table 3 below. Example which assumes the case of decreasing in the order of 500 W, 300 W, and 1000 W will be described. In the equation shown in the above equation 1, the power generation efficiency of the commercial power source 7 is 0.366.

When the main output following the current power load is 1000 W, the operation efficiency of the partial output (750 W) smaller than that main output of the fuel cell 1 is the operation efficiency at the main output of the fuel cell 1. Since the output is higher than the efficiency, the output of the fuel cell 1 is set to the partial output (750 W) instead of the suppressed main output operation in which the output of the fuel cell 1 is set to the suppressed main output that is smaller than the main output by the suppression width. The partial output operation is performed.
When the main output following the current power load is 750 W or 500 W, the operating efficiency of the partial output smaller than the main output of the fuel cell 1 is the operating efficiency of the main output of the fuel cell 1. Therefore, the output of the fuel cell 1 is suppressed by a suppression width smaller than the main output, rather than the partial output operation in which the output of the fuel cell 1 is set to the partial output as the output reduction operation in the operation control unit 5. The restraining main output operation to be set to the main output is executed.

  In the said embodiment, in addition to the hot water tank 2, the heat consumption terminal 3 was provided, and the cogeneration system which made the heat load the hot water supply heat load and the terminal heat load was illustrated, However, Hot water supply is not provided without providing the heat consumption terminal 3. It is good also as a cogeneration system which makes a heat load a heat load.

  In the above embodiment, the electric heater 12 is configured to heat the cooling water of the fuel cell 1. However, the electric heater 12 may be configured to heat the hot water in the hot water tank 2. It is.

  In the above embodiment, the fuel cell 1 is exemplified as the combined heat and power device. However, as the combined heat and power device, for example, a combination of an internal combustion engine such as a gas engine and a power generation device, or an external combustion engine such as a Stirling engine and power generation. It is also possible to adapt a combination with a device.

  The cogeneration system according to the present invention includes, for example, a fuel cell as a combined heat and power supply device, and appropriately reduces the output of the combined heat and power supply device at a time when the excess heat state is predicted. It can be applied to a cogeneration system and its operation method for appropriately suppressing the deterioration of the water.

Schematic configuration diagram of cogeneration system Cogeneration system control block diagram Illustration of main operation control Explanatory diagram in main output operation Graph showing predicted power load and predicted heat load The flowchart which shows the adjustment process of the suppression width | variety in suppression electric power main output driving | operation The flowchart which shows the determination process about execution of the suppression electric main output driving | operation The flowchart which shows the determination process about the form of the suppression electric power main output driving | operation

Explanation of symbols

1: Fuel cell (cogeneration device)
2: Hot water storage tank 5: Operation control unit (operation control means)
X: Surplus power deriving means

Claims (5)

A combined heat and power device that generates heat and electric power together, a hot water tank that collects the heat generated by the combined heat and power device and stores it as hot water, and outputs the set output of the combined heat and power device when the combined heat and power device is in operation An operation method of the cogeneration system provided with operation control means for executing electric main operation control to follow the load,
When the operation control means assumes that the main operation control has been executed for the predicted power load, the heat surplus countermeasure is the time when the occurrence of the heat surplus state is predicted or the time when the heat surplus state occurs. A power reduction operation for reducing the output of the fuel cell is performed at a time;
When the operation efficiency at the partial output of the combined heat and power device is higher than the operation efficiency when the main operation control is executed, the output of the combined heat and power device is partially output to the operation control means as the output reduction operation. When the partial output operation set to output is executed, and the operation efficiency at the partial output of the cogeneration device is lower than or equal to the operation efficiency when the electric main operation control is executed, the operation control means The operation method of the cogeneration system which performs the suppression electric main output operation which sets the output of the said combined heat and power supply apparatus to the suppression electric main output smaller by the predetermined | prescribed suppression width than the said electric power load as the said output fall operation. A combined heat and power device that generates heat and electric power together, a hot water tank that collects the heat generated by the combined heat and power device and stores it as hot water, and outputs the set output of the combined heat and power device when the combined heat and power device is in operation A cogeneration system provided with operation control means for executing electric main operation control to follow the load,
When the operation control means assumes that the main operation control has been executed for the predicted power load, the heat surplus countermeasure is the time when the occurrence of the heat surplus state is predicted or the time when the heat surplus state occurs. When the operation is performed to reduce the output of the fuel cell to reduce the output of the fuel cell and the operation efficiency at the partial output of the combined heat and power supply device is higher than the operation efficiency when the electric main operation control is executed, As the output reduction operation, a partial output operation in which the output of the cogeneration device is set to a partial output is executed, and the operation efficiency at the partial output of the cogeneration device is higher than the operation efficiency when the electric main operation control is executed. If the output is reduced or equal, the output reduction operation is performed by setting the output of the combined heat and power device to a suppressed main output that is smaller than the power load by a predetermined suppression width. Cogeneration system to run. An electric heater that converts surplus power that is a surplus with respect to the power load of the generated power of the cogeneration apparatus into heat that is stored in the hot water tank;
Surplus power deriving means for calculating or measuring the surplus power,
The cogeneration system according to claim 2, wherein the operation control unit adjusts the suppression width based on surplus power calculated or measured by the surplus power deriving unit in the suppressed power main output operation.   The said operation control means calculates the average value or integrated value of the surplus power calculated or measured by the said surplus power deriving means, The said suppression width is set according to the said average value or integrated value. Cogeneration system.   The upper limit value of the suppression width is set according to any one of claims 3 and 4, wherein the operation control means sets the upper limit value of the suppression width in a form in which a heat shortage state is not predicted when it is assumed that the suppressed power main output operation has been executed. Cogeneration system.

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