JP2017129323A - Co-generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a co-generation system that enhances a utilization rate of an electrothermal cogeneration device with high efficiency to increase an energy conservation amount, furthermore, to properly conduct demand response by a simple control configuration.SOLUTION: In the co-generation system, operation control means 5B for controlling operation of the electrothermal cogeneration device controls a power generation amount of the electrothermal cogeneration device at the current time up to a rated power generation amount of the electrothermal cogeneration device, as an upper limit, in a demand response time zone, while up to an upper limit value of a controlling electric power generation amount, as an upper limit, in a time zone other than a demand response time zone.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a cogeneration system including a combined heat and power supply device that generates electric power and heat and a hot water storage tank.

Such a cogeneration system can supply electric power and heat on-site, and thus well meets the current social demand for energy saving.
As an example of a cogeneration system equipped with a combined heat and power supply device and a hot water storage tank, there is a household cogeneration system equipped with a combined heat and power supply device such as a fuel cell or an engine-driven generator that is becoming popular in today's homes. Can do. In this system, the electric power generated by the combined heat and power supply device is consumed in each household, and the exhaust heat further covers the heat demand of each household (for example, a hot water supply load or a heating load).

  As a conventional example of this type of cogeneration system, the operation control means that controls the operation of the combined heat and power unit operates the combined heat and power unit in a main operation mode that adjusts the amount of power generated according to fluctuations in power demand (electric power load). In addition, there is one configured to store the exhaust heat generated with the operation of the combined heat and power supply device as hot water in a hot water storage tank and supply hot water from the hot water storage tank when hot water is required (for example, Patent Document 1).

That is, for example, fuel cells and engine-driven generators are capable of so-called partial load operation. Therefore, when the power load is lower than the rated output (substantially maximum output), the amount of power generation corresponding to the power load is generated. In a situation where the power load exceeds the rated output, operation at the rated output is performed.
Looking at the power generation status from the amount of hot water stored in the hot water storage tank, in the partial load situation, the hot water volume increases in proportion to the load, but when the power load exceeds the rated load, the hot water volume increases at the maximum increase. Will be.

  Although not described in Patent Document 1, as a system operation mode, in general, when the hot water storage amount of the hot water storage tank reaches a set upper limit amount (full tank) while operating in the above-described main power configuration, The operation is stopped (for example, see Patent Document 2 (see paragraph [0003]), and the amount of hot water stored in the hot water storage tank is reduced below a predetermined amount (for example, about 30% of the set upper limit amount). In this state, a form in which the cogeneration apparatus is operated again is adopted.

  As another conventional example, the power demand (power load) and heat demand (heat load) for the past several weeks are stored, and the heat demand and power demand for the actual operation day and the following two days are stored. , Based on the stored power demand and heat demand, and based on the predicted power demand and heat demand, as the operation mode of the combined heat and power unit, an operation mode that can obtain the highest merit such as energy saving and economic efficiency is sought. Thus, the applicant has proposed a technique for performing operation on the operation day in the obtained operation mode (see, for example, Patent Document 3).

  The driving mode that provides the highest merit is the load-following continuous driving mode that follows the power load on the operating day, and the continuous suppression mode that operates with a smaller amount of power generation than the power load on the operating day in some time zones on the operating day. Operation mode, forced continuous operation mode that operates with a larger amount of power generation than the power load on the operation day in a part of the operation day, operation stopped in a part of the operation day, and operation in the remaining time period Intermittent operation mode that follows the power load of the day, suppressed intermittent operation mode that stops operation in a part of the time zone of the operation day and operates with a power generation amount smaller than the power load of the operation day in the remaining time zone, and Select from multiple types of operation modes such as forced intermittent operation mode that stops operation in some time zone on the operating day and operates with power generation amount larger than the power load on the operating day in the remaining time zone Is will be.

  By the way, for example, in the suppression continuous operation mode, the time zone for operation with a power generation amount smaller than the power load on the operation day is set to the optimal time zone of the day while changing the start time and the end time. The optimum driving mode is set for each time zone of the day while changing the starting time and the ending time among a plurality of types of driving modes.

JP 2001-258293 A Japanese Patent Laid-Open No. 2004-263942 JP 2008-185317 A

  In the cogeneration system of Patent Document 1, the operation of the combined heat and power unit is set as the main operation, and the operation of the combined heat and power unit is stopped when the amount of hot water stored in the hot water storage tank reaches the set upper limit (full tank). Driving is performed in a driving mode in which the driving is restarted when the value becomes equal to or less than the predetermined amount. In the operation mode, since the cogeneration device is operated in a form that follows the power demand (power load), the power demand (power load) is near noon or in the time zone at night when the power demand (power load) tends to be small. In many cases, the combined heat and power unit is operated with a partial load with low efficiency, and it cannot be said that sufficient energy-saving effects are achieved.

  Moreover, since the technique disclosed in Patent Document 3 evaluates energy saving performance, economic efficiency, and the like for each of a plurality of types of driving modes, and selects a driving mode having a high merit, so the driving mode is determined. The control configuration becomes complicated due to the necessity of performing a large amount of computations in order to perform the operation, and the time zone and power generation that are operated on the operation day based on the past power demand and heat demand. Since the amount of electricity is determined, the power demand and heat demand on the operating day are changed to the past power demand and heat demand (in other words, the power demand and heat demand predicted based on the past power demand and heat demand). On the other hand, if it is significantly different, it cannot be said that it can appropriately respond to the power demand and heat demand on the operating day.

Also, in recent years, in response to demands for suppressing power consumption peaks based on incentives and electricity charges, the customer side sets the supply power peak on the supplier side (the maximum value of the total power consumption of the total consumers in the supply range on the supplier side). Various power supply companies are working on demonstration projects for demand response, that is, demand response, in which power consumption is changed for each time period so as to suppress.
However, with a relatively simple control configuration, while maintaining the hot water storage state of the hot water storage tank in a suitable state, the power coverage ratio that covers the power consumption with the power generation amount of the combined heat and power supply device is increased, and the demand response is increased. There has been no known cogeneration system that can be performed properly.

  The present invention has been made in view of the above circumstances, and its purpose is to maintain the hot water storage state of the hot water storage tank in a suitable state with a simple control configuration, and to reduce the power consumption by the amount of power generated by the combined heat and power supply device. The power coverage ratio can be increased, and even when the power demand and heat demand on the operating day differ from the predicted power demand and heat demand, it is possible to respond appropriately and efficiently. It is to provide a cogeneration system capable of increasing the energy saving amount by increasing the utilization rate of the co-feeding device and further appropriately performing demand response.

The cogeneration system to achieve the above objective is
It is a cogeneration system equipped with a heat and power cogeneration device that generates electric power and heat and a hot water storage tank, and its characteristic configuration is
An evaluation target period setting unit that repeatedly sets a future evaluation target period over time,
A demand prediction unit that predicts power demand and heat demand for each target time period within the evaluation target period;
A demand response time zone setting unit for setting a demand response time zone within the evaluation target period;
A power generation amount upper limit provisional setting unit for temporarily setting an upper limit value of the power generation amount of the cogeneration device;
From the predicted electric power demand and the power generation amount upper limit value that is temporarily set, an exhaust heat amount prediction unit that obtains an estimated exhaust heat amount for each target time zone of the cogeneration device,
A hot water storage amount prediction unit for obtaining a predicted hot water storage amount of the hot water storage tank for each target time zone from a current hot water storage amount of the hot water storage tank and a predicted heat demand and an estimated waste heat amount;
The maximum power generation that satisfies the condition that the predicted hot water storage amount is less than the set maximum hot water storage amount of the hot water tank by operating the power generation amount upper limit temporary setting unit, the exhaust heat amount prediction unit, and the hot water storage amount prediction unit. A power generation amount upper limit setting unit for control that repeatedly searches the amount upper limit value and sets the searched maximum power generation amount upper limit value as a control power generation amount upper limit value as time elapses,
The operation control means for controlling the operation of the combined heat and power supply unit is configured to use the combined heat and power supply with the rated power generation amount of the combined heat and power supply unit as an upper limit during a demand response time period and with the upper limit value of the power generation amount for control other than the demand response time period as an upper limit. The point is to control the power generation amount of the device at the current time.

In other words, when the evaluation target period setting unit repeatedly sets the future evaluation target period as time elapses, the power demand and heat demand for each target time zone within the evaluation target period are determined according to the setting. It is predicted by the prediction unit.
In the present application, the terms “electric power demand” and “heat demand” simply mean “electric power demand” and “heat demand” on the customer side equipped with the cogeneration system according to the present application.

  Then, the control power generation amount upper limit setting unit operates the power generation amount upper limit temporary setting unit, the exhaust heat amount prediction unit, and the hot water storage amount prediction unit, and the predicted hot water storage amount is less than the set maximum hot water storage amount of the hot water storage tank. Searching for the maximum power generation amount upper limit value that satisfies the above conditions and setting the found maximum power generation amount upper limit value as the control power generation amount upper limit value is repeated as time passes.

In addition, when the upper limit value of the power generation amount of the combined heat and power unit is temporarily set within the adjustment range of the power generation amount of the combined heat and power unit, the power predicted by the demand prediction unit Based on the demand and the power generation amount upper limit value temporarily set, a predicted exhaust heat amount for each target time zone of the combined heat and power supply apparatus is obtained by the exhaust heat amount prediction unit.
Then, the hot water storage amount prediction unit determines the target time in the evaluation target period based on the current hot water storage amount of the hot water storage tank, the heat demand predicted by the demand prediction unit, and the predicted exhaust heat amount obtained by the exhaust heat amount prediction unit. The predicted hot water storage amount of the hot water storage tank for each belt is obtained, and it is determined whether or not all of the calculated predicted hot water storage amounts for each target time zone are less than the set maximum hot water storage amount of the hot water storage tank.

  In other words, while taking into account the current hot water storage capacity of the hot water storage tank, the predicted hot water storage capacity of the hot water storage tank for each target time period in the evaluation target period is obtained, and all the calculated predicted hot water storage capacity for each target time period is set in the hot water storage tank. It is determined whether or not it is less than the maximum hot water storage amount.

  In this way, the predicted hot water storage amount of the hot water storage tank for each target time zone in the evaluation target period is obtained, and whether or not all of the calculated predicted hot water storage amount for each target time zone is less than the set maximum hot water storage amount of the hot water storage tank. Is determined for each of the power generation amount upper limit values temporarily set while changing within the adjustment range of the power generation amount of the combined heat and power device, and the predicted hot water storage amount predicted among the power generation amount upper limit values to be temporarily set Is searched for the maximum power generation amount upper limit value while satisfying the condition that the hot water storage tank is less than the set maximum hot water storage amount, and the searched maximum power generation amount upper limit value is set as the control power generation amount upper limit value.

As described above, in the present invention, the operation control means for controlling the operation of the cogeneration device controls the power generation amount at the current time of the cogeneration device with the upper limit value of the power generation amount for control other than the demand response time period as the upper limit. Will be.
Furthermore, in the present invention, in order to appropriately execute the demand response, the demand response time zone setting unit sets a time zone in which the demand response is executed within the evaluation target period described above. Here, the demand response time zone is, for example, set by the power supply company or the like as a time zone in which the amount of supplied power is maximum in order to suppress the supply power peak on the power supplier side of the power supply company or the like. Suppose it is a thing.
The operation control means for controlling the operation of the cogeneration device controls the power generation amount at the current time of the cogeneration device with the rated power generation amount of the cogeneration device as the upper limit in the demand response time zone.

  Note that the exhaust heat amount prediction unit obtains the predicted exhaust heat amount for each target time zone of the combined heat and power supply device from the predicted power demand and the power generation amount upper limit value that is provisionally set. In order to set the time zone, the exhaust heat amount prediction unit obtains the predicted exhaust heat amount assuming that the combined heat and power device operates with the rated power generation amount as the upper limit in the demand response time zone.

  As described above, according to the cogeneration system of the present invention, while setting the future evaluation target period, the condition that the predicted hot water storage amount is less than the set maximum hot water storage amount of the hot water storage tank is set for the set evaluation target period. Since the maximum power generation amount upper limit value that satisfies the maximum is searched and the found maximum power generation amount upper limit value is set as the control power generation amount upper limit value, the hot water storage capacity of the hot water storage tank will be set to the maximum hot water storage capacity in the future. Exceeding the amount can be avoided, and further, the combined heat and power device can be operated in a state where the energy saving amount is increased by increasing the utilization rate of the highly efficient combined heat and power device.

  In this way, the combined heat and power unit can be operated with a power generation amount that can prevent the hot water storage amount of the hot water storage tank from exceeding the set maximum hot water storage amount in the future, so that the hot water storage amount of the hot water storage tank does not exceed the set maximum hot water storage amount. Therefore, it is possible to avoid stopping the operation of the combined heat and power supply device, so that it is possible to increase the power coverage ratio that covers the power consumption with the power generation amount of the combined heat and power supply device while maintaining the hot water storage state of the hot water storage tank in a suitable state. It is.

  In addition, the period to be evaluated in the future is repeatedly set as time passes, and the maximum power generation amount that satisfies the condition that the predicted hot water storage amount is less than the maximum hot water storage amount set for the hot water storage tank is searched. Then, since the searched maximum power generation amount upper limit value is set as the control power generation amount upper limit value repeatedly with time, the power demand and heat demand on the operation day are Even if it differs from the predicted power demand and heat demand, the current hot water storage amount is updated from the exhaust heat amount and heat demand according to the power demand on the operating day, so set an appropriate upper limit value for power generation for control Will be able to.

  Further, in order to search for the maximum power generation amount upper limit value set as the control power generation amount upper limit value, according to the temporarily set power generation amount upper limit value, the predicted exhaust heat amount for each target time zone and each target time zone Although the predicted hot water storage amount of the hot water storage tank is calculated, the amount of calculation for determining the predicted exhaust heat amount for each target time zone of the combined heat and power unit from the predicted power demand and the power generation amount upper limit value temporarily set, and the hot water storage tank For the amount of calculation for obtaining the predicted hot water storage capacity of the hot water storage tank for each target time zone from the current hot water storage amount, predicted heat demand, and predicted exhaust heat amount, select an operation mode with a large merit from the conventional multiple operation modes Compared with the amount of calculation to do this, it is much less, so the control configuration can be simplified.

  In short, according to the cogeneration system of the present invention, with a simple control configuration, while maintaining the hot water storage state of the hot water storage tank in a suitable state, the power coverage ratio that covers the power consumption with the power generation amount of the combined heat and power supply device is increased. In addition, even when the power demand and heat demand on the operating day differ from the predicted power demand and heat demand, the utilization rate of the high-efficiency combined heat and power supply device will be increased appropriately. Therefore, it is possible to provide a cogeneration system that can increase the energy saving amount and can appropriately perform demand response.

Further features of the cogeneration system
The exhaust heat quantity prediction unit is an operation mode for generating the rated power generation amount of the combined heat and power device during the demand response time zone, and the power demand is less than the power generation amount upper limit value except for the demand response time zone. A point that is configured to predict the predicted exhaust heat amount in an operation mode of generating electric power that satisfies demand and generating electric power of the upper limit of power generation amount when the power demand is equal to or higher than the upper limit of power generation amount. It is in.

That is, when the exhaust heat amount prediction unit predicts the predicted exhaust heat amount, the demand response time zone is an operation mode in which the rated power generation amount of the combined heat and power generation device is generated. When the power demand is less than the upper limit value, power that satisfies the power demand is generated, and when the power demand is equal to or greater than the power generation amount upper limit value, the predicted exhaust heat amount is predicted in an operation mode that generates power at the power generation amount upper limit value.
In particular, as described above, in the demand response time zone, by operating in the operation mode that generates the rated power generation amount of the combined heat and power supply device, while contributing well to the peak cut in the power supply company, the incentives and electricity associated therewith Customers will be able to enjoy the benefits based on the charges.
When the above control is executed, the power demand may be lower than the rated power generation amount in the demand response time zone. However, in the demand response time zone, since the demand for power is high in the commercial power system, It is assumed that it will be possible, and for the amount of power exceeding the power demand, the economic advantage of the reverse tide can be enjoyed by the reverse tide.

  Thus, since the predicted exhaust heat amount is predicted, the predicted hot water storage amount of the hot water storage tank for each target time zone is in a state suitable for the operation mode in which the combined heat and power supply device is actually operated by the operation control means. The state where the maximum power generation amount upper limit value that is obtained and set as the control power generation amount upper limit value conforms to the actual operation mode including the demand response when the combined heat and power unit is capable of reverse tide by the operation control means. Will be required.

Further features of the cogeneration system
In the demand response time zone, the exhaust heat amount prediction unit generates power that satisfies the power demand when the power demand is less than the rated power generation amount, and the rated power when the power demand is equal to or greater than the rated power generation amount. In an operation mode for generating power of the amount of power generation, except the demand response time zone, when the power demand is less than the power generation amount upper limit value, power that satisfies the power demand is generated, and the power demand is the power generation amount upper limit. If the value is equal to or greater than the value, the predicted exhaust heat quantity is configured to be predicted in an operation mode in which the power of the power generation amount upper limit value is generated.

That is, when the exhaust heat amount prediction unit predicts the predicted exhaust heat amount, the demand response time zone generates power that satisfies the power demand if the power demand is less than the rated power generation amount. If the power demand is less than the power generation limit upper limit, the power that satisfies the power demand is generated, and the power demand is the power generation upper limit. In the above case, the predicted exhaust heat amount is predicted in the operation mode in which the power of the power generation amount upper limit value is generated.
As a result, in the demand response time zone, the combined heat and power unit does not generate power exceeding the power demand, so for example, it is possible to operate the combined heat and power unit in a form that is suitable for situations where reverse power flow is not possible. This makes it possible for consumers to enjoy the benefits based on the incentives and electricity charges associated therewith, while making good contributions to peak cuts in power supply companies.

  Thus, since the predicted exhaust heat amount is predicted, the predicted hot water storage amount of the hot water storage tank for each target time zone is in a state suitable for the operation mode in which the combined heat and power supply device is actually operated by the operation control means. The power generation amount upper limit value that is obtained and set as the control power generation amount upper limit value is in a state that conforms to the actual operation mode including the demand response in the case where the combined heat and power unit cannot reverse power flow with the operation control means. It will be required.

Further features of the cogeneration system
Outside the demand response time zone set by the demand response time zone setting unit, when the control power generation amount upper limit value at the current time is the minimum power generation amount, it is configured to stop the operation of the cogeneration device. There is in point.

According to the above characteristic configuration, when the hot water storage capacity of the hot water storage tank is close to the set maximum hot water storage amount and the combined heat and power unit is operated with the minimum power generation amount, the operation is stopped outside the demand response time zone, By operating in the response time zone, the customer can enjoy the benefits based on the incentives associated with demand response and electricity charges. In addition, the operation time of the combined heat and power supply device with the minimum power generation amount with relatively low overall efficiency can be shortened, and further energy saving effect can be expected.
Here, the minimum power generation amount means the lower limit value of the adjustment range of the power generation amount of the cogeneration device.

Further features of the cogeneration system
The demand response time zone setting unit is configured to set a time zone in which the power purchase unit price for each time zone is higher than a predetermined lower limit set power purchase price as the demand response time zone.

  According to the above characteristic configuration, the power purchase unit price for each time zone is higher than the predetermined lower limit set power purchase price, that is, the time zone in which the advantage received by the customer based on the incentive and the electricity rate associated with demand response is large, Economic efficiency can be improved by setting a demand response time zone.

Diagram showing the overall configuration of the cogeneration system Block diagram showing control configuration The figure which shows the functional block of the operation control device Flow chart showing control contents of operation control device A table showing power demand, power generation amount, hot water storage amount, etc. when setting the control power generation amount upper limit value when operating without back tide by demand response (demand response) during demand response time zone A table showing power demand, power generation amount, hot water storage amount, etc. when setting the control power generation amount upper limit value when operating with reverse tide by demand response (demand response) during demand response time zone Table showing power demand, power generation amount, hot water storage amount, etc. when setting the control power generation amount upper limit value when operating without reverse tide without demand response (demand response) Graph showing power demand and power generation when operating without back tide with demand response (demand response) during demand response time Graph showing power demand and power generation when operating with reverse tide by demand response (demand response) during demand response time zone Graph showing power demand and power generation when operating without reverse tide without demand response

  Below, the cogeneration system of this invention and its operating method are demonstrated. Preferred embodiments will be described below, but these embodiments are described in order to more specifically illustrate the present invention, and various modifications can be made without departing from the spirit of the present invention. The present invention is not limited to the following description.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Configuration of cogeneration system]
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 as hot water storage means for storing hot water into the hot water storage tank 2 and supplying a heat medium to the heat consuming terminal 3 using water, an operation control device 5 for controlling the operation of the fuel cell 1 and the hot water storage unit 4, etc. It is composed of

Since the fuel cell 1 is well known, the detailed description and illustration thereof will be omitted. Briefly, the fuel cell 1 includes a cell stack that generates power by being supplied with a fuel gas containing hydrogen and an oxygen-containing gas. A fuel gas generation unit that generates fuel gas to be supplied to the stack, a blower that supplies air as an oxygen-containing gas to the cell stack, and the like are provided.
The fuel gas generation unit is separate from a desulfurizer that desulfurizes hydrocarbon-based raw fuel gas such as city gas (for example, natural gas-based city gas) supplied, and desulfurized raw fuel gas supplied from the desulfurizer. A reformer that generates a reformed gas mainly composed of hydrogen by reforming the supplied steam, and carbon monoxide in the reformed gas supplied from the reformer is converted into carbon dioxide with steam. It is composed of a transformer for transformation treatment, a carbon monoxide remover that selectively oxidizes carbon monoxide in the reformed gas supplied from the transformer with selective oxidation air supplied separately, and transforms carbon monoxide. The reformed gas reduced by the treatment and the selective oxidation treatment is supplied to the cell stack as a fuel gas.

And it is comprised so that the electric power generation amount of the fuel cell 1 may be adjusted by adjusting the supply amount of the raw fuel gas to a fuel gas production | generation part.
Incidentally, in the present embodiment, the power generation amount of the fuel cell 1 is configured to increase or decrease between 300 to 700 Wh with 10 Wh as a unit amount.

A grid interconnection inverter 6 is provided on the power output side of the fuel cell 1, and the inverter 6 sets the generated power of the fuel cell 1 to the same voltage and the same frequency as the received power received from the commercial power supply 7. It is configured as follows.
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 a power purchase amount measuring means 11a and a power generation amount measurement means 11b for measuring the load power of the power load 9, and the value of the load power is obtained by adding the power purchase amount and the power generation amount.

  The hot water storage unit 4 includes a hot water circulation pump 17 that circulates hot water in the hot water storage tank 2 through the hot water circulation path 16 and a heat source circulation pump 21 that circulates hot water for heat source through the heat source circulation path 20 in addition to the hot water storage tank 2 described above. A heat medium circulating pump 23 that circulates and supplies the heat medium to the heat consuming terminal 3 through the heat medium circulation path 22, a hot water storage heat exchanger 24 that heats hot water flowing through the hot water circulation path 16, and a heat source circulation path 20. The heat source heat exchanger 25 for heating the flowing hot water for the heat source, the heat exchanger for heat medium heating 26 for heating the heat medium flowing through the heat medium circulation path 22, and the hot water supply path 27 taken out from the hot water storage tank 2. An auxiliary heater 28 for heating the hot water flowing through and the heat source hot water flowing through the heat source circulation path 20 is provided.

A hot water circulation path 16 is provided to connect the bottom and top of the hot water storage tank 2, and hot water extracted from the bottom of the hot water storage tank 2 is returned to the top of the hot water storage tank 2 by the operation of the hot water circulation pump 17. The hot water in the hot water storage tank 2 is circulated through the hot water circulation path 16.
The hot water circulated through the hot water circulation path 16 is heated by the hot water storage heat exchanger 24 so that the hot water is stored in a state where a temperature stratification is formed in the hot water storage tank 2.

  The hot water supply path 27 is connected to the hot water storage tank 2 via a flow path portion downstream of the hot water storage heat exchanger 24 in the hot water circulation path 16, and hot water in the hot water storage tank 2 passes through the hot water supply path 27 and passes through the bathtub. The hot water tank is configured to be supplied to a hot water supply destination such as a hot water tap and a shower. In addition, the hot water storage tank 2 is configured to supply water to the hot water storage tank 2 through a water supply passage 29 connected to the bottom of the hot water storage tank 2. ing.

  The heat source circulation path 20 is provided so as to form a circulation path in a state where a part of the hot water supply path 27 is shared, and the heat source circulation path 20 is provided with an intermittent valve for heat source for intermittently flowing the hot water for the heat source. 33 is provided.

  The auxiliary heater 28 combusts in the auxiliary heating heat exchanger 28a provided in the hot water supply passage 27 shared with the heat source circulation path 20, the burner 28b for heating the auxiliary heating heat exchanger 28a, and the burner 28b. And a combustion control section (not shown) for controlling the operation of the auxiliary heater 28. The combustion control section supplies hot water supplied to the auxiliary heating heat exchanger 28a. The amount of gas fuel supplied to the burner 28b is adjusted so that the hot water is heated to the target hot water temperature and discharged.

The cooling water circulation path 13 is provided in a form that branches into the hot water storage heat exchanger 24 side and the heat source heat exchanger 25 side, and the flow rate of the cooling water that flows to the hot water storage heat exchanger 24 side at the branch point And a flow dividing valve 30 for adjusting the ratio of the flow rate of the cooling water to be flowed to the heat source heat exchanger 25 side.
Incidentally, the diverter valve 30 passes the whole amount of the cooling water in the cooling water circulation path 13 to the hot water storage heat exchanger 24 side or the whole amount of the cooling water in the cooling water circulation path 13 to the heat source heat exchanger 25 side. It is configured so that it can be adjusted to the flow state.

The hot water storage heat exchanger 24 heats the hot water flowing through the hot water circulation path 16 by collecting the generated heat (exhaust heat) of the fuel cell 1 and flowing the cooling water flowing through the cooling water circulation path 13. Is configured to do.
In the heat source heat exchanger 25, the generated heat (exhaust heat) of the fuel cell 1 is collected and the cooling water flowing through the cooling water circulation path 13 is caused to flow, so that the heat source circulation path 20 flows. It is comprised so that hot water may be heated.

  In the heat exchanger for heat medium heating 26, the heat medium flowing through the heat medium circulation path 22 is heated by passing hot water for the heat source heated by the heat exchanger for heat source 25 and the auxiliary heater 28. Is configured to do. In addition, the heat consumption terminal 3 is comprised by heating terminals, such as a floor heating apparatus and a bathroom heating apparatus.

The hot water supply passage 27 is provided with hot water supply heat load measuring means 31 for measuring the hot water supply heat load when hot water is supplied to the hot water supply destination, and the terminal heat for measuring the terminal heat load corresponding to the heat consuming terminal 3. Load measuring means 32 is provided.
In addition, although illustration is abbreviate | omitted, these hot water supply thermal load measurement means 31 and the terminal thermal load measurement means 32 are the temperature sensor which detects the temperature of the flowing hot water and heat medium, and the flow volume which detects the flow volume of hot water and a heat medium. And a sensor, and configured to detect a thermal load based on a detected temperature of the temperature sensor and a detected flow rate of the flow sensor.

  A hot water storage temperature sensor Sh that detects the temperature of the hot water heated by the hot water storage heat exchanger 24 and supplied to the hot water storage tank 2 is provided at a location downstream of the hot water storage heat exchanger 24 in the hot water circulation path 16. The water supply passage 29 is provided with a water supply temperature sensor Si that detects the temperature of the water supplied to the hot water storage tank 2.

  The hot water storage tank 2 has an upper end temperature sensor S1 for detecting the temperature of hot water at the upper end of the upper layer portion of the hot water storage tank 2 and hot water at the boundary between the upper layer portion and the middle layer portion of the hot water storage tank 2 for detecting the amount of stored hot water. An intermediate upper temperature sensor S2 for detecting the temperature of the hot water tank, an intermediate lower temperature sensor S3 for detecting the temperature of hot water at the boundary between the middle layer and the lower layer of the hot water storage tank 2, and hot water at the lower end of the lower layer of the hot water storage tank 2 A lower end temperature sensor S4 is provided for detecting the temperature.

  The operation controller 5 detects the temperature of the hot water in the hot water storage tank 2 detected by the upper end temperature sensor S1, the intermediate upper temperature sensor S2, the intermediate lower temperature sensor S3, and the lower end temperature sensor S4, and the feed water temperature sensor Si. The hot water storage heat amount (hot water storage amount) of the hot water storage tank 2 is determined based on the supplied water temperature, and the operation control device 5 determines the current hot water storage amount confirmation means 5C for determining the current hot water storage amount of the hot water storage tank 2 (see FIG. 3).

That is, the hot water storage amount confirmation means 5C is configured to obtain the hot water storage amount (hot water storage amount) of the hot water storage tank 2 by the following calculation method.
The hot water temperatures in the hot water storage tank 2 detected by the upper end temperature sensor S1, the intermediate upper temperature sensor S2, the intermediate lower temperature sensor S3, and the lower end temperature sensor S4 are T1, T2, T3, and T4, respectively. The water supply temperature detected by the temperature sensor Si is Ti, and the capacities of the upper layer portion, the middle layer portion, and the lower layer portion are V1, V2, and V3 (liters).

  Further, assuming that the weighting coefficient in the upper layer part is B1, the weighting coefficient in the middle part is B2, and the weighting coefficient in the lower layer part is B3, the hot water storage amount (hot water storage amount) (kcal) is calculated by the following (Equation 1). can do.

Hot water storage heat amount = (B1 × T1 + (1-B1) × T2-Ti) × V1
+ (B2 * T2 + (1-B2) * T3-Ti) * V2
+ (B3 * T3 + (1-B3) * T4-Ti) * V3 (Formula 1)

  The weighting factors B1, B2, and B3 are empirical values that consider past temperature distribution data in each layer of the hot water storage tank 2. Here, as B1, B2, and B3, for example, B1 = B2 = 0.2 and B3 = 0.5. B1 = B2 = 0.2 indicates that the influence of the temperature T2 is larger than the influence of the temperature T1 in the upper layer portion. This indicates that 80% of the upper layer is close to the temperature T2, and 20% is close to the temperature T1. The same applies to the middle layer portion. In the lower layer part, it shows that the influence of temperature T3 and T4 is the same.

[Operation details of the operation control device]
The operation control device 5 controls the operation of the fuel cell 1 while the cooling water circulation pump 15 is operated during the operation of the fuel cell 1.
The operation control device 5 controls the operation of the hot water circulation pump 17, the heat source circulation pump 21, the heat medium circulation pump 23, the flow dividing valve 30, and the heat source intermittent valve 33, thereby supplying hot water into the hot water storage tank 2. A hot water storage operation for storing hot water and a heat medium supply operation for supplying a heat medium to the heat consuming terminal 3 are performed.

  The operation control device 5 performs a hot water storage operation in a state where no operation command is issued from a terminal remote controller (not shown) for the heat consuming terminal 3, and in the hot water storage operation, the diverter valve 30 supplies the entire amount of cooling water to the hot water storage heat. The temperature of the hot water supplied to the hot water storage tank 2 is preset based on the detection information of the hot water storage temperature sensor Sh in a state in which the state is switched to the state of flowing through the exchanger 24 and the heat source intermittent valve 33 is closed. The operation of the hot water circulation pump 17 is controlled so as to adjust the hot water circulation amount so as to reach the target hot water storage temperature (for example, 60 ° C.). By this hot water storage operation, hot water at the target hot water temperature is stored in the hot water storage tank 2.

  When the operation is commanded from the terminal remote controller, the operation control device 5 performs a heat medium supply operation. In the heat medium supply operation, the heat source intermittent valve 33 is opened and the heat source circulation pump 21 is preset. The flow dividing valve 30 is configured to control the amount of cooling water corresponding to the terminal heat load at the heat consuming terminal 3 to flow to the heat source heat exchanger 25 in a state of operating at the set rotational speed. In such a state where the heat medium supply operation is performed, when the diverter valve 30 is controlled so as to allow the cooling water to flow also to the hot water storage heat exchanger 24 side, the operation of the hot water circulation pump 17 is controlled as described above. Thus, the hot water storage operation is executed in parallel with the heat medium supply operation.

  When the operation control device 5 is instructed to stop the operation from the terminal remote controller during the heat medium supply operation, the operation control device 5 switches the diversion valve 30 to a state in which the entire amount of the cooling water is allowed to flow to the hot water storage heat exchanger 24 side. The heat source intermittent valve 33 is closed, the heat source circulation pump 21 is stopped, and the hot water circulation pump 17 is operated to switch from the heat medium supply operation to the hot water storage operation.

  Incidentally, during the hot water supply operation in which hot water in the hot water storage tank 2 is supplied to the hot water supply destination through the hot water supply passage 27 or during the execution of the heat medium supply operation, the combustion control unit of the auxiliary heater 28 performs the heat exchanger for auxiliary heating. When the temperature of hot water supplied to 28a is lower than the target hot water temperature, the amount of gas fuel supplied to the burner 28b is adjusted to heat the hot water supplied to the auxiliary heating heat exchanger 28a to the target hot water temperature. Will do.

[Search / setting configuration for upper limit of power generation for control]
The above is the basic configuration of the cogeneration system according to the present invention. Hereinafter, operation control for operating the fuel cell 1 while controlling the power generation amount will be described.
That is, the operation control of the fuel cell 1 will be described while describing the search for the upper limit value of the power generation amount of the fuel cell 1 having a unique configuration of the present invention and the setting method thereof.
The power generation amount upper limit value is a control index value of the power generation amount at the current time, and in the present invention, the maximum power generation amount upper limit value is referred to as “control power generation amount upper limit value”.

  As shown in FIGS. 2, 3, and 5, the operation control device 5 operates for the purpose of searching and setting the “control power generation amount upper limit value” of the present invention, The operation control means 5B for controlling the power generation amount at the current time of the fuel cell 1 with the “power generation amount upper limit value” as the upper limit value, and the supply on the power supplier side such as a power supplier within the evaluation target period K1, for example In order to suppress the power peak, the power supply provider is configured to function as a demand response time zone setting unit 5D that sets a demand response time zone K2, which is a time zone during which the amount of power supplied by the power supplier increases.

The current power generation amount setting means 5A sets the “control power generation amount upper limit value” for the current time zone, and the operation control means 5B sets the demand response time zone K2 set by the demand response time zone setting unit 5D in the combined heat and power supply. The power generation amount at the current time of the fuel cell 1 is controlled with the rated power generation amount of the fuel cell 1 as an apparatus as the upper limit and the “control power generation amount upper limit value” as the upper limit except for the demand response time zone K2.
More specifically, the operation control means 5B generates power (so-called main operation) that satisfies the power demand when the power demand is less than the rated power generation amount of the fuel cell 1 during the demand response time zone K2. When the power demand is greater than or equal to the rated power generation amount, the operation mode generates power with the rated power generation amount. Except for the demand response time zone K2, when the power demand is less than the power generation amount upper limit value, power that satisfies the power demand is generated. When the power demand is equal to or greater than the power generation amount upper limit value, power of the power generation amount upper limit value is generated.
The demand response time zone setting unit 5D is configured to set a time zone in which the power purchase unit price for each time zone is higher than a predetermined lower limit set power purchase price as the demand response time zone K2, FIG. In the example shown in FIG. 8, the demand response time zone K2 is set from 10:00 to 16:00 on that day.
Here, the lower limit set power purchase price is appropriately set from the viewpoint of economy based on the fluctuating power purchase unit price.

  As shown in FIG. 3, the current power generation amount setting means 5A includes an evaluation target period setting unit A1 that repeatedly sets a future evaluation target period K1 as time elapses, and power for each target time period within the evaluation target period K1. A demand prediction unit A2 that predicts demand and heat demand, a power generation amount upper limit temporary setting unit A3 that temporarily sets an upper limit value of the power generation amount of the fuel cell 1, and a predicted power demand and a power generation amount upper limit value that is temporarily set From the exhaust heat amount prediction unit A4 for obtaining the predicted exhaust heat amount for each target time zone of the fuel cell 1, and the hot water storage tank 2 for each target time zone from the current hot water storage amount of the hot water storage tank 2, the predicted heat demand and the predicted exhaust heat amount. The hot water storage amount prediction unit A5 for obtaining the predicted hot water storage amount and the control power generation amount upper limit value setting unit A6 are provided.

  Then, the control power generation amount upper limit value setting unit A6 operates the power generation amount upper limit value temporary setting unit A3, the exhaust heat amount prediction unit A4, and the hot water storage amount prediction unit A5, and the predicted predicted hot water storage amount is set in the hot water storage tank 2. Searching for the maximum power generation amount upper limit value that satisfies the condition of less than the maximum hot water storage amount, and repeatedly setting the found maximum power generation amount upper limit value as the control power generation amount upper limit value over time It is configured as follows.

In this embodiment, the evaluation target period setting unit A1 is configured to repeatedly set 24 hours as a future evaluation target period K1 every hour as time elapses.
That is, every time 1 hour elapses, 24 hours as the future evaluation target period K1 is newly set, and the future evaluation target period K1 is repeatedly set as time elapses.
For example, as shown in FIG. 5, when the time changes from 7 o'clock to 8 o'clock, the period from 8 o'clock to 7 o'clock on the next day is set as the future evaluation target period K1, and the time is 8 o'clock. At 9 o'clock from the stand, the future evaluation target period K1 is repeatedly set as time elapses, such as setting the future evaluation target period K1 from 9:00 to the next 8 o'clock.

The demand prediction unit A2 predicts the power demand and the heat demand for each target time zone within the evaluation target period K1, based on the past power demand information and the heat demand information stored in the past information storage unit 34a. become.
That is, the past information storage unit 34 a is configured using the memory 34 (see FIG. 2) connected to the operation control device 5. And in this embodiment, the operation control apparatus 5 memorize | stores in the memory 34, updating the electric power demand for every hour about the past one week sequentially as past electric power demand information, and as past heat demand, The hourly heat demand for the past week is stored in the memory 34 while being sequentially updated.

Then, the demand prediction unit A2 predicts the power demand and the heat demand in the evaluation target period K1 based on the past power demand and the past heat demand corresponding to one week before the evaluation target period K1.
For example, as shown in FIG. 5, a future evaluation target period K1, that is, power demand and heat demand between 8 o'clock and 7 o'clock in the next day are predicted every hour. Become.

Incidentally, in this embodiment, in order to simplify the description, the heat demand will be described assuming that there is only a hot water supply heat load and no terminal heat load. That is, it is assumed that only the hot water storage operation is performed while the fuel cell 1 is in operation, and all the exhaust heat of the fuel cell 1 is used for hot water storage in the hot water storage tank 2.
When the heat medium supply operation is performed during the operation of the fuel cell 1, the amount of heat consumed in the heat medium supply operation is subtracted from the exhaust heat of the fuel cell 1, and the remaining portion is stored as hot water storage. The calculation is performed assuming that the tank 2 is used for hot water storage.

In the present embodiment, the power generation amount upper limit temporary setting unit A3 is configured to temporarily set the upper limit value of the power generation amount of the fuel cell 1 between, for example, 300 to 700 Wh, with 10 Wh as a unit amount. Yes.
By the way, in this embodiment, first, the case where the minimum power generation amount is set to 300 Wh, and then the temporary power generation amount is increased to 10 Wh sequentially, but conversely, first, the maximum power generation amount is illustrated. The form of temporarily setting the upper limit value of the power generation amount of the fuel cell 1 can be changed in various ways, such as setting the amount to 700 Wh and then temporarily setting the power generation amount to 10 Wh.

The exhaust heat amount prediction unit A4 is configured to obtain the predicted exhaust heat amount per hour for the target time zone for each hour in the evaluation target period K1.
And in this embodiment, according to the driving | running form of the operation control means 5B, the waste heat amount prediction part A4 is a demand response time slot | zone K2, when the power demand is less than the rated power generation amount of the fuel cell 1, the power demand is calculated. Generates sufficient power (so-called main operation) and generates power of the rated power generation when the power demand is equal to or greater than the rated power generation. If the power demand is less than the power generation amount, the power generation is generated. If the power demand is equal to or higher than the power generation amount upper limit value, the power generation amount upper limit value is generated. .
When the explanation is added, in the embodiment, it is assumed that the reverse tide is not possible. For this reason, the operation control means 5B has the power demand of the fuel cell 1 in the demand response time zone K2. If it is less than the rated power generation amount, only the electric power that satisfies the electric power demand is generated (so-called electric main operation), and the fuel cell 1 is operated so as not to generate reverse power.

The predicted exhaust heat amount kcal per hour for each target time zone of the evaluation target period K1 is obtained by the following formula based on the power generation amount Wh for the target time zone.
Predicted exhaust heat amount = power generation amount / power generation efficiency × exhaust heat efficiency × 0.86 (kcal / Wh) (Equation 2)

The hot water storage amount prediction unit A5 is configured to obtain the predicted hot water storage amount for the target time zone for each hour in the evaluation target period K1.
That is, the predicted hot water storage amount kcal for the current time corresponding to the start time of the evaluation target period K1 (in other words, the predicted hot water storage amount kcal one hour after the current time) is determined by the current hot water storage amount confirmation means 5C. Current hot water storage amount kcal to be confirmed, heat demand kcal per hour for the target time (current time) predicted by the demand prediction unit A2, and target time (current time) predicted by the exhaust heat amount prediction unit A4 ) On the basis of the predicted exhaust heat quantity kcal per hour.
Predicted hot water storage amount at the current time = Current hot water storage amount + Predicted waste heat amount−Heat demand (Equation 3)

Moreover, the predicted hot water storage amount kcal whose target time is one hour after the current time (in other words, the predicted hot water storage amount kcal two hours after the current time) is stored in the predicted hot water storage amount and demand prediction unit A2 at the current time. Heat demand kcal per hour for the target time predicted at this time (time one hour after the current time) and the target time predicted at the exhaust heat quantity prediction unit A4 (time one hour after the current time) Based on the predicted exhaust heat quantity kcal per hour, the following equation is used.
Predicted hot water storage time 1 hour after the current time = Predicted hot water storage amount of current time + Predicted exhaust heat amount−Heat demand (Equation 4)

Hereinafter, the predicted hot water storage amount kcal after the target time is 2 hours after the current time (in other words, the predicted hot water storage amount kcal after 3 hours from the current time) is also the time when the target time is 1 hour after the current time. It is obtained in the same manner as the predicted hot water storage amount kcal.
That is, the target predicted by the demand prediction unit A2 from the value obtained by adding the predicted amount of hot water stored per hour at the target time predicted by the exhaust heat amount prediction unit A4 to the predicted hot water storage amount one hour before the target time By subtracting the heat demand kcal per hour for the time, the predicted hot water storage amount kcal for each target time can be obtained.

  The control power generation amount upper limit value setting unit A6 searches for the maximum power generation amount upper limit value that satisfies the condition that the predicted hot water storage amount is less than the set maximum hot water storage amount of the hot water storage tank 2, and finds the maximum Setting the power generation amount upper limit value as the control power generation amount upper limit value is repeatedly performed as time elapses. That is, the condition that all of the predicted hot water storage amount per hour for the target time zone for each hour in the evaluation target period K1 predicted by the hot water storage amount prediction unit A5 is less than the set maximum hot water storage amount of the hot water storage tank 2. The maximum power generation amount upper limit value that satisfies the above is searched, and the found maximum power generation amount upper limit value is set as the control power generation amount upper limit value.

In the present embodiment, the control power generation amount upper limit setting unit A6 has a time interval (for example, 15 minutes) shorter than the unit time (1 hour in the present embodiment) of the target time zone in the evaluation target period K1. In the interval, the control power generation amount upper limit value is repeatedly set.
That is, the power demand and heat demand for each target time zone predicted by the demand prediction unit A2 do not change during the unit time of the target time zone (1 hour in the present embodiment), but the current hot water storage The amount changes every moment, and the current hot water storage amount confirmation means 5C can check the current hot water storage amount changing every moment, so that the unit time of the target time zone within the evaluation target period K1 (in this embodiment, 1 hour) ), The control power generation amount upper limit value is repeatedly set at a time interval shorter than (for example, every 15 minutes).

Next, the control content of the control power generation amount upper limit setting unit A6 will be described with reference to the case illustrated in FIG. Here, in order to simplify the description, the upper limit value of the power generation amount of the fuel cell 1 is temporarily set between 300 to 700 Wh, with 100 Wh as a unit amount.
That is, when the time changes from 7 o'clock to 8 o'clock, the evaluation target period setting unit A1 sets the period from 8 o'clock to 7 o'clock on the next day as the future evaluation target period K1, and the demand prediction unit A2 The electric power demand DJ and the heat demand NJ in the set future evaluation target period K1, that is, from 8 o'clock to 7 o'clock on the next day, are predicted every hour.
Further, the current hot water storage amount confirmation means 5C confirms that the current hot water storage amount GT is 4500 kcal. As described above, in the present embodiment, the set maximum hot water storage amount MT of the hot water storage tank 2 is 8600 kcal.

Next, when the power generation amount upper limit temporary setting unit A3 first sets the power generation amount upper limit value HM of the fuel cell 1 to 300 Wh, which is the minimum power generation amount, the exhaust heat amount prediction unit A4 sets the power generation amount upper limit value to 300 Wh. In some cases, the predicted amount of exhaust heat per hour for the target time zone for each hour in the evaluation target period K1 is obtained.
That is, in the demand response time period K2, when the power demand is less than the rated power generation amount of the fuel cell 1, power that satisfies the power demand DJ is generated (so-called main operation), and the power demand DJ is equal to or higher than the rated power generation amount. If the power demand DJ is less than the power generation amount upper limit value HM, power that satisfies the power demand DJ is generated and the power demand DJ is generated except for the demand response time zone. When the amount is equal to or higher than the amount upper limit value HM, the predicted exhaust heat amount is predicted in an operation mode of generating electric power of the power generation amount upper limit value HM.

Subsequently, the hot water storage amount prediction unit A5 obtains the predicted hot water storage amount per hour for the hourly target time zone in the evaluation target period K1.
That is, the current hot water storage amount kcal confirmed by the current hot water storage amount confirmation means 5C, the heat demand kcal per hour in the target time zone predicted by the demand prediction unit A2, and the exhaust heat amount prediction unit A4 The predicted hot water storage amount is determined based on the predicted exhaust heat amount kcal per hour in the predicted target time zone.

  In the case illustrated in FIG. 5, the prediction result of the hot water storage amount prediction unit A5, that is, the predicted hot water storage amount per hour for the target time zone for each hour in the evaluation target period K1, is the maximum setting of the hot water storage tank 2. Since there is no case where the hot water storage amount MT is exceeded, the control power generation amount upper limit setting unit A6 does not set the power generation amount upper limit value 300Wh as the control power generation amount upper limit value in this calculation stage.

  When the power generation amount upper limit value 300 Wh is not set as the control power generation amount upper limit value, the power generation amount upper limit value temporary setting unit A3 sets the power generation amount upper limit value HM of the fuel cell 1 to 400 Wh. Similarly to the case where the upper limit value HM is set to 300 Wh, when the heat generation amount prediction unit A4 has the power generation amount upper limit value of 400 Wh, the per hour of the target time zone for each hour in the evaluation target period K1. The predicted waste heat amount is obtained, and subsequently, the hot water storage amount prediction unit A5 obtains the predicted hot water storage amount per hour for the target time zone for each hour in the evaluation target period K1.

  In the case illustrated in FIG. 5, the prediction result of the hot water storage amount prediction unit A5, that is, the predicted hot water storage amount per hour for the target time zone for each hour in the evaluation target period K1, Since there is no case where the hot water storage amount MT is exceeded, the control power generation amount upper limit value setting unit A6 does not set the power generation amount upper limit value 400Wh as the control power generation amount upper limit value in this calculation stage.

  When the power generation amount upper limit value 400 Wh is not set as the control power generation amount upper limit value, the power generation amount upper limit value temporary setting unit A3 sets the power generation amount upper limit value HM of the fuel cell 1 to 500 Wh. Similarly to the case where the upper limit value HM is set to 300 Wh, when the heat generation amount prediction unit A4 has a power generation amount upper limit value of 500 Wh, the per hour of the target time zone for each hour in the evaluation target period K1. The predicted waste heat amount is obtained, and subsequently, the hot water storage amount prediction unit A5 obtains the predicted hot water storage amount per hour for the target time zone for each hour in the evaluation target period K1.

  In the case illustrated in FIG. 5, the prediction result of the hot water storage amount prediction unit A5, that is, the predicted hot water storage amount per hour for the target time zone for each hour in the evaluation target period K1, Since there is no case where the hot water storage amount MT is exceeded, the control power generation amount upper limit value setting unit A6 does not set the power generation amount upper limit value 500Wh as the control power generation amount upper limit value in this calculation stage.

  When the power generation amount upper limit value 500 Wh is not set as the control power generation amount upper limit value, the power generation amount upper limit value temporary setting unit A3 sets the power generation amount upper limit value HM of the fuel cell 1 to 600 Wh. Similarly to the case where the upper limit value HM is set to 300 Wh, when the heat generation amount prediction unit A4 has a power generation amount upper limit value of 600 Wh, per hour for the target time zone for each hour in the evaluation target period K1. The predicted waste heat amount is obtained, and subsequently, the hot water storage amount prediction unit A5 obtains the predicted hot water storage amount per hour for the target time zone for each hour in the evaluation target period K1.

  In the case illustrated in FIG. 5, the prediction result of the hot water storage amount prediction unit A5, that is, the predicted hot water storage amount per hour for the target time zone for each hour in the evaluation target period K1, Since there is a case where the hot water storage amount MT is exceeded, for the first time in this calculation stage, the control power generation amount upper limit value setting unit A6 is set as the maximum power generation amount upper limit value that satisfies the condition of being less than the set maximum hot water storage amount of the hot water storage tank 2. , 500 Wh, which is one step lower than 600 Wh, is selected, and this 500 Wh is set as the control power generation amount upper limit value.

  Incidentally, even if the power generation amount upper limit value is sequentially increased from 300 Wh and set to the maximum 700 Wh, the prediction result of the hot water storage amount prediction unit A5, that is, 1 for the target time zone for each hour in the evaluation target period K. When the predicted hot water storage amount per hour does not exceed the set maximum hot water storage amount MT of the hot water storage tank 2, the control power generation amount upper limit value setting unit A6 sets a condition that the hot water storage tank 2 is less than the set maximum hot water storage amount. As a maximum power generation amount upper limit value that is satisfied, 700 Wh is set as the control power generation amount upper limit value.

  In the present embodiment, the control power generation amount upper limit setting unit A6 has a time interval (for example, 15 minutes) shorter than the unit time (1 hour in the present embodiment) of the target time zone in the evaluation target period K1. Since the control power generation amount upper limit value is repeatedly set at the interval), the timing when the control power generation amount upper limit value is set coincides with the current time corresponding to the start time of the evaluation target period K1, and the evaluation There is a case where the current time corresponding to the start time of the target period K1 is deviated (delayed).

  That is, in the present embodiment, the evaluation target period setting unit A1 is configured to repeatedly set 24 hours as the future evaluation target period K1 every hour as time elapses. When the control power generation amount upper limit setting unit A6 sets the control power generation amount upper limit value every 15 minutes, the timing for setting the control power generation amount upper limit value corresponds to the start time of the evaluation target period K1. 4 times appearing from the time to the next target time one hour later, the time corresponding to the start time, the time delayed by 15 minutes, the time delayed by 30 minutes, and the time delayed by 45 minutes However, in this embodiment, in any case, the hot water storage amount prediction unit A5 is configured to obtain the predicted hot water storage amount in the same calculation form.

In other words, either when the timing for setting the control power generation amount upper limit value coincides with the current time corresponding to the start time of the evaluation target period K1 or when the timing deviates from the current time corresponding to the start time of the evaluation target period K1. The current hot water storage amount at that time is confirmed by the current hot water storage amount confirmation means 5C.
The current hot water storage amount kcal confirmed by the current hot water storage amount confirmation means 5C, the heat demand kcal per hour for the target time (current time) predicted by the demand prediction unit A2, and the exhaust heat amount prediction unit A4 Based on the predicted exhaust heat quantity kcal per hour of the target time (current time) predicted by (1), the following equation (3) is used.
Predicted hot water storage amount at the current time = Current hot water storage amount + Predicted waste heat amount−Heat demand (Equation 3)

The timing for setting the control power generation amount upper limit value coincides with the current time corresponding to the start time of the evaluation target period K1, and the case where the timing deviates from the current time corresponding to the start time of the evaluation target period K1. The method for obtaining the predicted hot water storage amount by the hot water storage amount prediction unit A5 may be varied.
That is, when the timing for setting the control power generation amount upper limit value coincides with the current time corresponding to the start time of the evaluation target period K1, the predicted hot water storage amount is obtained as described above.

If the timing for setting the control power generation amount upper limit value deviates from the current time corresponding to the start time of the evaluation target period K1, the predicted hot water storage amount kcal from the current time to the next target time is confirmed as the current hot water storage amount confirmation. Current hot water storage amount kcal confirmed by means 5C, heat demand kcal per hour for target time (current time) predicted by demand prediction unit A2, target time predicted by exhaust heat amount prediction unit A4 ( Based on the predicted exhaust heat quantity kcal per hour (current time) and the ratio of the remaining time to one hour from the current time to the next target time, the following equation may be used.
Predicted hot water storage amount at the current time = Current hot water storage amount + (Predicted exhaust heat amount−Heat demand) × Ratio …… (Formula 5)

[Search / setting procedure for upper limit of power generation for control]
The control operation of the current power generation amount setting means 5A will be described based on the flowchart of FIG. Note that the flowchart of FIG. 4 is described as one control process (subroutine) among a plurality of control processes sequentially executed by the operation control device 5.

  First, it is determined whether or not it is the setting timing of the evaluation target period K1 every hour (# 1). If it is determined that it is the setting timing of the evaluation target period K1, a process of setting the evaluation target period is performed. This is executed (# 2), and subsequently, a demand prediction process for predicting power demand and heat demand at each target time within the evaluation target period K1 is executed (# 3).

  When it is determined in the process of # 1 that it is not the set timing of the evaluation target period K1, and after executing the processes of # 2 and # 3, the power purchase unit price for each time zone is a predetermined lower limit set power purchase price A process of setting a higher time zone as the demand response time zone K2 is executed (# 4).

  After executing the process of # 4, it is determined whether or not it is the power generation amount upper limit setting timing determined every 15 minutes (# 5). When it is not the power generation amount upper limit setting timing, the process of # 1 is performed. Will be transferred to.

  When it is determined in the process of # 5 that the set timing is reached, a process of checking the current hot water storage amount (# 6), a process of setting the power generation amount upper limit value to the minimum power generation amount (300 Wh) (# 7), and an evaluation target Exhaust heat amount prediction process (# 8) for obtaining the exhaust heat amount for each target time zone within the period K1 and hot water storage amount prediction process (# 9) for obtaining the predicted hot water storage amount for each target time zone within the evaluation target period K1 Execute.

  Next, based on the result of the hot water storage amount prediction process of # 9, the predicted hot water storage amount for each target time zone within the evaluation target period K1 exceeds the set maximum hot water storage amount (8600 kcal) of the hot water storage tank 2 Is determined, that is, whether or not the predicted hot water storage amount exceeds the set maximum hot water storage amount (8600 kcal) (# 10), and if not, the power generation amount upper limit value is maximum (700 Wh) (# 11), if it is not the maximum, a process for increasing the power generation amount upper limit value by the unit quantity (10 Wh) is executed (# 12), and then the process proceeds to # 8. It will be.

  In the # 8 waste heat amount prediction process, the demand response time zone K2 generates power that satisfies the power demand (so-called main operation) when the power demand is less than the rated power generation amount of the fuel cell 1, If the power demand is greater than or equal to the rated power generation amount, it is an operation mode that generates the power of the rated power generation amount.Other than the demand response time zone, if the power demand is less than the upper limit value of the power generation amount, it generates power that satisfies the power demand, When the power demand is equal to or greater than the power generation amount upper limit value, the predicted exhaust heat amount is predicted in an operation mode in which power of the power generation amount upper limit value is generated.

  In the process of # 10, when it is determined that the predicted hot water storage amount exceeds the set maximum hot water storage amount (8600 kcal), the power generation amount upper limit value before the unit amount increase is set to the control power generation amount upper limit value (# 13), and then the process proceeds to # 1. When the power generation amount upper limit before the unit amount increase is less than the minimum power generation amount, the minimum power generation amount is set as the control power generation amount upper limit value.

  Further, when it is determined in the process of # 11 that the power generation amount upper limit value is the maximum, a process of setting the current power generation amount upper limit value to the control power generation amount upper limit value is executed (# 14). The process proceeds to # 1.

  By the way, in the processes of # 5 to # 14, the process of temporarily setting the power generation amount upper limit value, the process of predicting the amount of exhaust heat, and the process of predicting the amount of stored hot water are repeatedly executed, so that the predicted amount of stored hot water is predicted. The maximum power generation amount upper limit value that satisfies the condition of less than the set maximum heat storage amount of the hot water storage tank 2 is searched, and the searched maximum power generation amount upper limit value is set as the control power generation amount upper limit value. The process for setting the upper limit value is repeatedly executed as time elapses.

  And since the process which sets the electric power generation amount upper limit for control is repeatedly performed at intervals of 15 minutes, at a time interval shorter than the unit time (1 hour) of the target time zone in the evaluation target period K1, It will be executed repeatedly.

[Operation results and evaluation of cogeneration system]
FIG. 8 is a graph showing changes in power demand and power generation over time when the operation control of the cogeneration system is performed by applying the embodiment, and FIG. 10 performs a demand response without performing reverse tide. It is a table | surface and graph figure which show the time-dependent change of the electric power demand at the time of performing operation control of a cogeneration system in the state which applies the control similar to the said embodiment about the other control.
Incidentally, FIG. 7 shows a numerical example for determining the control power generation amount upper limit value in the operation mode shown in FIG. In the example shown in FIG. 7, when the power generation amount upper limit value is sequentially increased from 300 W, there is a case where the set maximum hot water storage amount MT of the hot water storage tank 2 exceeds 700 W, so the power generation amount upper limit value is set to 600 W. Yes.

  8 and 10, the predicted hot water storage amount is controlled so as not to exceed the maximum hot water storage amount, but the graph shown in FIG. 8 and the graph shown in FIG. Are compared, it can be seen that the power generation amount in the demand response time zone indicated by K2 in the graph of FIG. 8 according to this embodiment is higher than the power generation amount in the graph shown in FIG. That is, in the graph shown in FIG. 8 according to the present embodiment, the amount of power purchased from the commercial power system can be reduced in the demand response time zone, and the customer can better benefit from the incentives and electricity charges associated therewith. You can enjoy it.

[Another embodiment]
Next, another embodiment will be listed.
(1) Although the case where the evaluation target period K1 is set to 24 hours is exemplified in the above embodiment, the evaluation target period K1 can be set to various lengths such as 12 hours and 36 hours.
Moreover, although the case where the evaluation target period K1 is repeatedly set every hour is illustrated in the above embodiment, for example, the evaluation target period K1 is repeatedly set as time elapses, such as being repeatedly set every 30 minutes. Various periods can be changed.

(2) In the above embodiment, in the case of predicting the power demand and heat demand for each target time zone of the evaluation target period K1, the case of predicting the power demand and heat demand for each hour is exemplified. The time interval for predicting the electric power demand and the heat demand, such as predicting the electric power demand and the heat demand every 30 minutes, can be variously changed.

(3) In the above-described embodiment, the maximum power generation amount found by searching for the maximum power generation amount upper limit value that satisfies the condition that the predicted hot water storage amount is less than the set maximum heat storage amount of the hot water storage tank 2. Although the case where the upper limit value is set as the control power generation amount upper limit value at a time interval shorter than the unit time of the target time zone in the evaluation target period K1 is exemplified, such setting is performed in the evaluation target period K1. May be performed in the same cycle as the cycle that is repeatedly set as time elapses.

(4) In the above embodiment, the case where the power generation amount of the fuel cell as the combined heat and power supply device is adjusted with 10 Wh as the unit amount is exemplified. However, for example, the power generation of the fuel cell is adjusted with 5 Wh as the unit amount. The unit amount for adjusting the amount can be variously changed.

(5) In the above-described embodiment, the fuel cell is exemplified as the combined heat and power supply device. However, various types of combined heat and power supply devices are available, such as using an engine-driven generator instead of the fuel cell. Applicable.

(6) In the embodiment described above, the control power generation amount upper limit value at the current time is the minimum power generation amount (the minimum that can be set in the fuel cell 1) other than the demand response time zone K2 set by the demand response time zone setting unit 5D. It is preferable that the operation of the fuel cell 1 be stopped.
In this case, the time for stopping the operation of the fuel cell 1 may be all or a part other than the demand response time zone K2, but the amount of heat exhausted when the operation of the fuel cell 1 is not stopped It is preferable to set a time that can be covered by operating the fuel cell 1 in the demand response time zone K2.

(7) In the demand response time zone, when the power generated by the combined heat and power supply device 1 of the cogeneration system can be reversed, the cogeneration system according to the present application is realized with the following configuration. Since the basic configuration of the cogeneration system is the same as that of the above-described embodiment, only the configuration and control different from the above-described embodiment will be described below, and the same configuration and control as those of the above-described embodiment will be described. The reference numeral is attached.
When performing a demand response, it is assumed that the reverse power from the cogeneration system of the consumer is permitted because the power demand in the commercial power system is usually large and the power purchase unit price is also high.
Therefore, in the cogeneration system according to the another embodiment, the operation control means 5B is configured so that the demand response time zone K2 is in order to reverse the excess power in the demand response time zone K2 and secure an economic merit. In the operation mode of generating the rated power generation amount of the fuel cell 1, except for the demand response time zone K2, when the power demand is less than the power generation amount upper limit value, power that satisfies the power demand is generated, and the power demand is the power generation amount upper limit value. In the above case, the power of the power generation amount upper limit value is generated.

The exhaust heat amount prediction unit A4 is an operation mode in which the demand response time zone K2 generates the rated power generation amount of the fuel cell 1 in accordance with the operation mode of the operation control means 5B. If the demand is less than the power generation amount upper limit value, power that satisfies the power demand is generated, and if the power demand is greater than or equal to the power generation amount upper limit value, the predicted exhaust heat amount is predicted with an operation mode that generates power at the power generation amount upper limit value. It is configured as follows.
When the power demand is equal to or greater than the rated power generation amount and the surplus power is generated in the demand response time zone K2, the operation control means 5B reversely flows the surplus power.

  Furthermore, regarding the search / setting procedure for the control power generation amount upper limit value, the demand response time zone K2 generates the rated power generation amount of the fuel cell 1 in the exhaust heat amount prediction process of # 8 in the flowchart shown in FIG. In the operation mode, except for the demand response time zone K2, when the power demand is less than the power generation amount upper limit value, power that satisfies the power demand is generated, and when the power demand is greater than the power generation amount upper limit value, the power of the power generation amount upper limit value is generated. The predicted exhaust heat amount is predicted in the operation mode for generating the power.

Next, the operation result and evaluation of the cogeneration system according to the another embodiment will be described.
FIG. 9 is a graph showing changes in power demand and power generation over time when operation control of the cogeneration system is performed by applying the other embodiment (when reverse tide is performed and demand response is performed).
FIG. 6 shows a numerical example for determining the control power generation amount upper limit value in the operation mode shown in FIG. In the example shown in FIG. 6, when the power generation amount upper limit value is sequentially increased from 300 W, there is a case where the set maximum hot water storage amount MT of the hot water storage tank 2 exceeds 500 W. Therefore, the power generation amount upper limit value is set to 400 W. Yes.

  When comparing the graph shown in FIG. 9 with the graph shown in FIG. 8 in the case of performing demand response without performing reverse tide, in any case, the predicted hot water storage amount is controlled not to exceed the maximum hot water storage amount. However, it can be seen that the power generation amount in the demand response time zone K2 indicated by K2 in the graph of FIG. 9 according to the another embodiment is a power generation amount that partially exceeds the power demand. That is, in the graph shown in FIG. 9 according to the another embodiment, surplus power exceeding the power demand in the rated power generation amount of the fuel cell 1 in the demand response time zone K2 is reversed, You can also enjoy the economic benefits of the reverse tide.

(8) In the above embodiment, the demand response time zone setting unit 5D sets a time zone in which the power purchase unit price for each time zone is higher than a predetermined lower limit set power purchase price as the demand response time zone K2. An example is shown. However, the demand response time zone setting unit 5D may set the demand response time zone K2 based on incentives other than the power purchase unit price presented by the power supply company or the like, without being separately based on the power purchase unit price. I do not care.

  The configuration disclosed in the above embodiment (including another embodiment, the same shall apply hereinafter) can be applied in combination with the configuration disclosed in the other embodiment, as long as no contradiction occurs. The embodiment disclosed in this specification is an exemplification, and the embodiment of the present invention is not limited to this. The embodiment can be appropriately modified without departing from the object of the present invention.

  The present invention can achieve an increase in the power coverage ratio that covers power consumption with the amount of power generated by the combined heat and power supply unit while maintaining the hot water storage state of the hot water storage tank in a suitable state by a simple control configuration, and Even if the power demand and heat demand on the operating day differ from the predicted power demand and heat demand, the energy consumption can be increased by increasing the utilization rate of the highly efficient combined heat and power supply equipment, appropriately. Can be suitably used as a cogeneration system capable of appropriately performing demand response.

DESCRIPTION OF SYMBOLS 1 Cogeneration apparatus 2 Hot water storage tank 5B Operation control means 5D Demand response time zone setting part A1 Evaluation object period setting part A2 Demand prediction part A3 Power generation amount upper limit temporary setting part A4 Waste heat amount prediction part A5 Hot water storage amount prediction part A6 Control power generation Volume upper limit setting section

Claims (5)

A cogeneration system comprising a cogeneration device that generates electric power and heat and a hot water storage tank,
An evaluation target period setting unit that repeatedly sets a future evaluation target period over time,
A demand prediction unit that predicts power demand and heat demand for each target time period within the evaluation target period;
A demand response time zone setting unit for setting a demand response time zone within the evaluation target period;
A power generation amount upper limit provisional setting unit for temporarily setting an upper limit value of the power generation amount of the cogeneration device;
From the predicted electric power demand and the power generation amount upper limit value that is temporarily set, an exhaust heat amount prediction unit that obtains an estimated exhaust heat amount for each target time zone of the cogeneration device,
A hot water storage amount prediction unit for obtaining a predicted hot water storage amount of the hot water storage tank for each target time zone from a current hot water storage amount of the hot water storage tank and a predicted heat demand and an estimated waste heat amount;
The maximum power generation that satisfies the condition that the predicted hot water storage amount is less than the set maximum hot water storage amount of the hot water tank by operating the power generation amount upper limit temporary setting unit, the exhaust heat amount prediction unit, and the hot water storage amount prediction unit. A power generation amount upper limit setting unit for control that repeatedly searches the amount upper limit value and sets the searched maximum power generation amount upper limit value as a control power generation amount upper limit value as time elapses,
The operation control means for controlling the operation of the combined heat and power supply unit has the rated power generation amount of the combined heat and power supply unit as an upper limit in a demand response time zone, and the combined heat and power supply as an upper limit of the power generation amount for control other than the demand response time zone. A cogeneration system that controls the power generation amount of the device at the current time.   The exhaust heat quantity prediction unit is an operation mode for generating the rated power generation amount of the combined heat and power device during the demand response time zone, and the power demand is less than the power generation amount upper limit value except for the demand response time zone. The system is configured to generate electric power that satisfies demand, and to predict the predicted exhaust heat amount in an operation mode in which when the electric power demand is greater than or equal to the upper limit value of power generation, the power of the upper limit value of power generation is generated. Item 1. A cogeneration system according to item 1.   In the demand response time zone, the exhaust heat amount prediction unit generates power that satisfies the power demand when the power demand is less than the rated power generation amount, and the rated power when the power demand is equal to or greater than the rated power generation amount. In an operation mode for generating power of the amount of power generation, except the demand response time zone, when the power demand is less than the power generation amount upper limit value, power that satisfies the power demand is generated, and the power demand is the power generation amount upper limit. 2. The cogeneration system according to claim 1, wherein the predicted exhaust heat amount is predicted in an operation mode of generating electric power of the power generation amount upper limit value when the value is equal to or greater than a value.   Outside the demand response time zone set by the demand response time zone setting unit, when the control power generation amount upper limit value at the current time is the minimum power generation amount, it is configured to stop the operation of the cogeneration device. The cogeneration system according to any one of claims 1 to 3.   The demand demand time zone setting unit is configured to set a time zone in which the power purchase unit price for each time zone is higher than a predetermined lower limit set power purchase price as a demand response time zone. A cogeneration system according to claim 1.

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