JP4087301B2 - Cogeneration system and its operation plan creation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cogeneration system (a combined heat and electricity system). In particular, it generates power according to power demand, stores the heat generated during power generation, and supplies the stored thermal energy when necessary, that is, the power generation amount of the cogeneration system following the power demand. It relates to a system that increases or decreases. Specifically, the cogeneration system is started and stopped by learning the changes in power demand per unit time and the fluctuation pattern of thermal energy supply per unit time, and controlling the start and end of the cogeneration system according to the learning results. The present invention relates to a technology for effectively utilizing the advantages of a generation system.
[0002]
[Prior art]
The cogeneration system includes a power generation unit that generates electric power and generated heat, a hot water storage tank, and a power generation heat recovery medium circulation path that sends the water in the hot water storage tank to the power generation unit, heats it with the generated heat, and returns it to the hot water storage tank. Water is heated using the generated heat generated with power generation, and the heated hot water is stored in a hot water storage tank. The hot water in the hot water tank is adjusted to an appropriate temperature, and hot water is supplied to a hot water use location (for example, a floor heating system, a bathtub, a shower, or a hot water tap). If hot water hotter than the hot water temperature required at the hot water use location is stored in the hot water storage tank, the hot water in the hot water storage tank can be adjusted to the required hot water temperature by mixing it with tap water. If hot water at a temperature lower than the hot water temperature required at the hot water use location is stored, it is necessary to further heat with an auxiliary heat source device arranged for temperature control. Since heating may be performed, a necessary amount of heat can be reduced as compared to heating tap water. Therefore, the cogeneration system has a high overall thermal efficiency.
[0003]
The cogeneration system can increase or decrease the amount of power generation or generated heat energy per unit time. Since the power demand per unit time and the thermal energy demand per unit time do not necessarily match, there is an operation method that adjusts the power generation amount of the cogeneration system following the power demand, and An operation method for adjusting the amount of heat energy generated by the generation system can be considered. Since it is more efficient to store thermal energy than to store electricity, a method of increasing or decreasing the amount of power generated by a cogeneration system following power demand is considered promising.
It is predicted that the cogeneration system is often used in combination with commercial power supplied by an electric power company, rather than being used alone. In this case, even if the power generation amount of the cogeneration system is increased or decreased following the power demand, it is desirable to use the commercial power when it is more efficient to use the commercial power. Considering only the power generated by the cogeneration system, the commercial power is more efficient, and the total efficiency of the cogeneration system exceeds the commercial power only after the generated heat is effectively used. Even if the method of increasing or decreasing the power generation amount of the cogeneration system following the power demand is not to follow the power demand regardless of the use of thermal energy, it follows the power demand within the limit where the generated heat is effectively used. If the generated heat cannot be used effectively, it is more efficient to stop the operation of the cogeneration system and use commercial power.
[0004]
In order to effectively use the cogeneration system, a technique for accurately controlling the start and end of operation of the cogeneration system, in other words, a technique for accurately controlling whether or not to use commercial power is required.
For the above control, it is necessary to know the power demand per unit time and the thermal energy demand per unit time. Since these differ depending on the installation environment of the cogeneration system, the cogeneration system learns the power demand and thermal energy demand per unit time in the installed environment, and the cogeneration system A technology for controlling start and end of operation is required.
[0005]
In Patent Literature 1, an electric power load and a thermal load at a planning target time are predicted from past electric power load results and heat load results. Then, the amount of heat generation energy obtained when the operation output of the cogeneration system is adjusted to follow the power demand is calculated. Then, the operation start time of the cogeneration system is determined by comparing the predicted heat load with the calorific value to be calculated. Use cogeneration systems to the extent that heat generation can be used without waste, and use commercial power when heat generation is not possible.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 15-61245
[0007]
[Problems to be solved by the invention]
In the above technique, the operation end time of the cogeneration system is set in advance. Specifically, the operation of the cogeneration system is stopped at 24:00. A large electric power load ends at 24:00, and the operation is ended at 24:00.
Generally, the peak of the heat load and the peak of the power load are both around 21:00. The heat load peaks during the bathing hours, when the bath is filled with water. When the bathing time period passes, hot water is hardly used after that, so the heat load decreases. On the other hand, the demand for power load is continued even after taking a bath, and continues to operate even after the bathing time period, because it is active and uses an air conditioner or the like. That is, the duration of the peak time zone of the thermal load and the power load is different, and the peak time zone of the thermal load ends earlier than the peak time zone of the power load. Therefore, when the cogeneration system is operated until the time when the peak of the power load ends, the power generation operation is performed even during a time period when no heat load is required, and heat is generated. Since the amount of heat generated during a time period when there is no thermal load request is not used, it is stored in the hot water tank and used the next day. In the technique of Japanese Patent Laid-Open No. 15-61245, since the operation of the cogeneration system is started by calculating the time when the necessary heat amount and the heat generation amount become equal, it is not stored excessively and is used the next day. Since the stored hot water is carried over and used the next day, the temperature of the hot water in the hot water is cooled, and the cooled hot water is used. In the conventional technology, since hot water is carried over to the next day, the efficiency is lowered, and the advantages of the cogeneration system cannot be fully utilized.
[0008]
An object of the present invention is to provide a cogeneration system that can obtain the necessary heat quantity and can use up the hot water in the hot water tank when the operation is stopped. Also provided is a method for creating a plan for operating such a cogeneration system.
[0009]
[Means, actions and effects for solving problems]
  The cogeneration system of the present invention basically generates power according to electric power demand, stores heat generated during power generation, and supplies the stored thermal energy when necessary. The system of the present inventionSimpleMeans for storing the amount of heat energy supplied per unit time;From past heat energy supply per unit timeMeans for determining the last heat energy supply time for each unit period in units of 24 hours;Per unit periodIdentifies the average time of the last heat energy supply timeAnd set to the scheduled end time of operation.Means,At the scheduled end timeMeans for terminating the operation of the cogeneration system;
  The present invention can also be referred to as a method for creating an operation plan for a cogeneration system. in this way,PastStoring the amount of heat energy supplied per unit time;From past heat energy supply per unit timeDetermining the last heat energy supply time for each unit period in units of 24 hours;Per unit periodIdentifies the average time of the last heat energy supply timeAnd set to the scheduled end time of operation.Process,At the scheduled end timeA step of creating an operation plan for terminating the operation of the cogeneration system.
In addition, when it is called the last heat energy supply time, it is preferable not to include using a small amount of warm water for a short time. It is preferable that the last heat energy supply time be the end time of a phenomenon in which a predetermined amount or more of hot water is continuously used for a predetermined time or more.
[0010]
According to the cogeneration system and the operation planning method of the present invention, the last heat energy supply time for each unit period in units of 24 hours in the past period is specified. The 24 hours have an initial period and an end period within a period mainly for sleeping. For example, a household that takes a bath at 10:00 on average and sleeps at 11:00 will be supplied with the last thermal energy at 10:00. You can see that
In the cogeneration system of the present invention, since the operation of the cogeneration system is stopped at the time when the heat energy is last supplied, and no heat is generated thereafter, it is minimal to carry over the generated heat on the next day. It can be suppressed to the limit. In this case, the operation of the cogeneration system may be stopped in spite of the power demand. In this case, the use of commercial power corresponds to the case where the efficiency is high, and this is more reasonable. By using the present invention, the advantages of the cogeneration system can be fully utilized.
[0011]
  In the cogeneration system of the present invention, when the average time of the last heat energy supply time for each unit period is specified, it is preferable to average the last heat energy supply time for each unit period on the same day in the past.
  Since life patterns are often determined for each day of the week, it is highly possible to calculate a time close to the last heat energy supply time of the operation implementation date by using the average of the data on the operation implementation date and the same day of the week.
[0012]
  In the cogeneration system of the present invention, it is preferable to determine the scheduled operation start time as follows. That is, in the above cogeneration system, means for storing the power supply amount for each past unit time, and means for calculating the total heat energy supply amount for each unit period from the past heat energy supply amount for each unit time And means for specifying the average amount of the total heat energy supply for each unit period, and the time retroactive from the scheduled operation end time, calculated from the total power supply amount from the retroactive time to the scheduled operation end time. A means for specifying the time when the total heat storage energy amount is equal to the average amount of the total heat energy supply amount for each unit period and setting it as the scheduled operation start time, and a means for starting the operation of the cogeneration system at the scheduled operation start time It is preferable to further have.
  Similarly,In the operation plan creation method of the cogeneration system of the present invention, a process of storing the power supply amount for each past unit time, and the total heat energy supply for each unit period from the past heat energy supply amount for each unit time The process of calculating the amount, the process of specifying the average amount of total heat energy supply per unit period, and the time retroactive from the scheduled operation end time, and the total power supply from the retroactive time to the scheduled operation end time The time when the total heat storage energy amount calculated from the amount is equal to the average amount of the total heat energy supply amount per unit period is specified, and the operation start scheduled time is set. It is preferable to further include a step of creating an operation plan for starting operation.
[0013]
  In the cogeneration system and the operation planning method of the present invention, the amount of heat generation energy per unit time is calculated from the past power supply amount per unit time. Moreover, the average amount of the total heat energy supply amount within the unit period in units of 24 hours is calculated from the past actual value. The operation start time is specified from these two types of information. As the operation start time, the time at which the accumulated heat energy amount when the heat energy amount per unit time after that time is accumulated until the end of the operation becomes equal to the total heat energy supply amount required in 24 hours is specified.
  As a result, if the power is generated following the power demand after the operation start time and the stored thermal energy is supplied as necessary, the stored thermal energy is used at the end of the operation, and the operation does not carry the stored energy the next day. Realized and fully exploits the benefits of cogeneration systems.
[0014]
  In the cogeneration system of the present invention,Unit periodeveryAverage amount of total heat energy supplyWhen identifying, pastUnit period on the same dayeveryAverage total heat energy supplyIt is preferable to do.
  As above,LivingThe live pattern is approximateSameThe day of the weekPer unit periodTotal heat energy supplyQuantityIf the average value is used, there is a high possibility that a value close to the total heat energy supply amount on the operation implementation date and the power supply amount per unit time on the operation implementation date can be calculated.
[0015]
  In the case of a cogeneration system, it may be preferable to use an upper limit time for the operation continuation time per time. For example, it may be preferable to set an upper limit time in order to ensure a certain service life or secure a maintenance time.
  For this reason, when the time from the scheduled operation start time set above to the scheduled operation end time exceeds the operation continuation upper limit time, means for delaying the operation start scheduled time is added so as not to exceed the upper limit time. Preferably it is.
  A method of delaying the scheduled operation start time rather than advancing the scheduled operation end time is extremely preferable because the upper limit time can be observed while the operation is centered on a period when the efficiency of the cogeneration system is high.
[0016]
  When the total amount of heat energy that can be stored in the heat storage means is stored, it becomes possible to specify the time when the next heat storage is possible from the past heat energy supply amount per unit time. In preparation for the case where the total amount of heat energy that can be stored is stored, means for specifying the next time when the heat can be stored, the balance when the operation of the cogeneration system is continued until the specified time, and cogeneration It is preferable to add means for comparing the balance when restarting the cogeneration system at the specified time after stopping the operation of the system and determining whether to continue or stop the operation..
[0017]
  If the total amount of heat energy that can be stored is stored, then the generated heat energy cannot be used effectively, and it is preferable that the operation of the cogeneration system is stopped and commercial power is used.
  However, starting operation of the cogeneration system requires preparation time and energy consumption for preparation, and if the operation of the cogeneration system is stopped for a short time, it is more efficient to continue the operation as it is Sometimes. The cogeneration system has a built-in function to operate while releasing heat energy into the atmosphere without storing it.
  If the amount of heat energy supplied per unit time is stored, when the entire amount of heat energy that can be stored has been stored, the next time that the heat can be stored can be specified, and until that time cogeneration It is possible to compare the balance when the system operation is continued with the balance when the cogeneration system operation is temporarily stopped and the cogeneration system operation is resumed at a specified time. The former is energy obtained by multiplying the heat generation amount per unit time of the cogeneration system by time, and the latter is energy required for preparation for starting the operation of the cogeneration system. By comparing the two and adopting the more advantageous one, the advantages of the cogeneration system can be more fully utilized.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
(Embodiment 1) The temperature detection means, water amount detection means, timing means and storage means necessary for efficient operation are composed of means necessary for operation control of the cogeneration system, and only for efficient operation Necessary measuring means are not added.
(Mode 2) The power generation unit includes a fuel cell, and generates electric power and generated heat.
(Mode 3) When the total amount of heat energy that can be stored in the heat storage means is stored, and it is more advantageous to continue the operation than to temporarily stop and restart the operation, the heat is dissipated by the radiator disposed in the power generation unit. While continuing the operation of the cogeneration system.
[0021]
【Example】
An embodiment embodying the present invention will be described with reference to the drawings. First, the configuration of the cogeneration system will be described. FIG. 1 is a schematic configuration diagram of a cogeneration system according to the present embodiment. As shown in FIG. 1, the cogeneration system 10 includes a power generation unit 20 that generates electric power and generated heat, a heat storage unit 15 that stores heat by storing warm water heated by the generated heat, and uses the warm water. The The heat storage unit 15 includes a hot water storage tank 44 that stores hot water heated by the generated heat, a mixing unit 72 that mixes hot water discharged from the hot water storage tank 44 and tap water, an auxiliary heat source machine for hot water supply and heating (hereinafter referred to as an auxiliary heat source machine). It is composed of 50 etc. The auxiliary heat source unit 50 heats and regulates the hot water that has passed through the mixing unit 72 and supplies the hot water to the hot water use location 40 and the bathtub 90, and also warms the hot water in the bathtub 90 and warms the heating medium. Heat to 92,96.
[0022]
The power generation unit 20 includes a fuel cell 22, a reformer 30 and the like, and is housed in a power generation unit housing 21. The reformer 30 generates hydrogen gas from hydrocarbon-based raw fuel gas. Since a high temperature is required to efficiently generate hydrogen gas, the reformer 30 has a burner 32 incorporated therein. Further, a combustion gas exhaust pipe 34 is connected to the reformer 30, and the combustion gas exhaust pipe 34 passes through the heat exchanger 70 and heats the water, and then is discharged out of the power generation unit housing 21 (in the drawing). Arrow).
The fuel cell 22 is composed of a plurality of cells. A pipe (not shown) communicating with the reformer 30 is connected to the fuel cell 22. Hydrogen gas generated by the reformer 30 is supplied to the fuel cell 22 through this pipe. The fuel cell 22 takes in oxygen in the air, and reacts the taken-in oxygen with hydrogen gas supplied from the reformer 30 to generate power.
[0023]
The fuel cell 22 generates heat during power generation. A heat medium circulation pipe 24 is connected to the fuel cell 22, and the heat medium flowing in the heat medium circulation pipe 24 collects generated heat generated during power generation. A heat medium circulation pump 8 is disposed in the heat medium circulation pipe 24. Pure water is used as the heat medium, and the pure water is obtained by passing tap water through a pure water generator (not shown).
The heat medium circulation pipe 24 is disposed so as to pass through the heat exchanger 74. The heat generated by the fuel cell 22 recovered by the heat medium is transferred to the heat exchanger 74.
A three-way valve 36 is disposed in the heat medium circulation pipe 24. The three-way valve 36 has one inlet and two outlets. The heat medium circulation pipe 24 is bifurcated by the three-way valve 36. Of the branched heat medium circulation pipe 24, a pipe connected to one outlet of the three-way valve 36 is disposed via the radiator 28, and a pipe connected to the other outlet is the radiator 28. It is arrange | positioned so that it may not be interposed. Which outlet of the three-way valve 36 is opened is controlled by a power generation unit controller (not shown). As a result, it is switched whether the heat medium circulates via the radiator 28 or circulates without passing through the radiator 28. Specifically, when the temperature of the heat medium measured by a thermistor (not shown) is abnormally high, the outlet of the three-way valve 36 is switched so that the heat medium circulates through the radiator 28. The radiator 28 cools the heat medium by blowing air. In addition, illustration 25 is a cis turn.
[0024]
The heat storage unit 15 includes a hot water storage tank 44, a mixing unit 72, an auxiliary heat source device 50, a control unit 60, and the like, and is housed in the heat storage unit housing 16.
The cogeneration system 10 is provided with a water supply pipe 64 for supplying tap water. The water supply pipe 64 branches into two hands, a first water supply pipe 64a and a second water supply pipe 64b. The first water supply pipe 64 a is connected to the lower part of the hot water storage tank 44. The second water supply pipe 64 b is connected to the cold water inlet 72 b of the mixing unit 72. A water supply thermistor T1 is disposed in the second water supply pipe 64b in the mixing unit 72, and is used to detect the temperature of the supplied tap water.
A first hot water discharge pipe 52 is connected to the upper part of the hot water storage tank 44, and the first hot water discharge pipe 52 is connected to a hot water inlet 72 a of the mixing unit 72. A first hot water thermistor T <b> 2 is disposed in the first hot water discharge pipe 52 in the mixing unit 72 and is used to detect the temperature of hot water discharged from the hot water storage tank 44.
[0025]
A pressure reducing valve 42 is disposed upstream of the branch portion 64 c of the water supply pipe 64. The pressure reducing valve 42 adjusts the pressure of tap water supplied to the hot water tank 44 and the mixing unit 72. When the hot water in the hot water storage tank 44 is used, or when the cold water inlet 72b of the mixing unit 72 is opened and the downstream pressure of the pressure reducing valve 42 becomes equal to or lower than the pressure regulation value, the pressure reducing valve 42 is opened and the hot water storage tank 44 and the mixing unit are opened. 72 is supplied with water. The pressure in the hot water tank 44 is maintained at a pressure lower than the tap water pressure.
[0026]
The mixing unit 72 has a hot water inlet 72a, a cold water inlet 72b, and a mixed water outlet 72c. Hot water in the hot water storage tank 44 flows into the hot water inlet 72a via the first hot water outlet pipe 52, and tap water flows into the cold water inlet 72b via the second water supply pipe 64b. The opening degree of the two inlets 72a and 72b is variable. That is, the inflow ratio of warm water and tap water is variable. These opening degrees are controlled by the control unit 60. By controlling the opening degree, for example, it is possible to shut off the tap water (close the cold water inlet 72b) and send only hot water from the outlet 72c, and conversely, shut off the hot water (hot water inlet 72a). It is also possible to send out only tap water from the outlet 72c. Also, for example, it is possible to mix 70% warm water and 30% tap water and send it out from the outlet 72c, adjust the mixing ratio of warm water and tap water, and discharge the mixed water adjusted to the required temperature to the outlet 72c can be sent out.
[0027]
The mixed water that has been mixed and adjusted in the mixing unit 72 is discharged from the outlet 72c. A second hot water discharge pipe 76 is connected to the outlet 72c. The second hot water outlet pipe 76 is connected to the hot water supply pipe 94 in the auxiliary heat source machine 50, and connects the mixing unit 72 and the auxiliary heat source machine 50. The pressure reduced by the pressure reducing valve 42 is applied to the two inlets 72 a and 72 b of the mixing unit 72. Therefore, the pressure of the mixed water discharged from the outlet 72 c of the mixing unit 72 is also equal to the pressure adjusted by the pressure reducing valve 42. A second hot water thermistor T3 is provided in the second hot water discharge pipe 76 in the mixing unit 72, and detects the temperature of the mixed water discharged from the mixing unit 72. A mixed water flow rate sensor F3 is disposed on the second hot water discharge pipe 76 in the mixing unit 72, and detects the flow rate of the mixed water discharged from the mixing unit 72.
[0028]
Between the heat storage unit 15 and the power generation unit 20, a pipe 4 for recovering the generated heat is disposed.
The forward pipe 4 a of the power generation heat recovery pipe 4 is connected to the bottom of the hot water tank 44, and the return pipe 4 b of the power generation heat recovery pipe 4 is connected to the top of the hot water tank 44. It passes through the heat exchanger 74 with the generated heat and the heat exchanger 70 with the reformer 30 disposed in the power generation unit 20, and becomes the return pipe 4 b of the power generation heat recovery pipe 4. The hot water heated by the two heat exchangers 70 and 74 in the power generation unit 20 is injected from the upper part of the hot water storage tank 44 through the return pipe 4b of the power generation heat recovery pipe 4 and stored, and is stored at the bottom of the hot water storage tank 44. Hot water is sent to the power generation unit 20 through the forward pipe 4 a of the power generation heat recovery pipe 4. Hot water and cold water stored in the hot water storage tank 44 form a temperature stratification and do not mix.
A power generation heat recovery pump 6 is disposed in the forward pipe 4 a of the power generation heat recovery pipe 4. When the power generation heat recovery pump 6 is driven, the hot water in the power generation heat recovery pipe 4 circulates (circulates in the direction of the arrow in the figure). The power generation heat recovery pump 6 is driven and controlled by the control unit 60.
[0029]
Next, the auxiliary heat source device 50 that performs the hot water supply operation and the heating operation will be described. The auxiliary heat source unit 50 is provided with two burners 38 and 56, a heating system 51, a plurality of pipes for guiding hot water, and the like, and is housed in an auxiliary heat source unit housing 49.
First, the hot water supply operation will be described. The hot water supply pipe 94 connected to the second hot water discharge pipe 76 is branched into two pipes, a pipe 94a and a pipe 94b. The end of the pipe 94a is connected to a hot water use location such as a kitchen faucet or a hot water tap of a bath, and the end of the pipe 94b is placed in the upper part of the heating system 51.
The hot water supply set temperature at the hot water use location is set by operating a remote controller (not shown). The pipe 94a is arranged so that the hot water in the pipe 94a is heated by the burner 38. The burner 38 is driven and controlled by the control unit 60. The pipe 94a is provided with a water amount sensor F1 and a hot water supply thermistor T4, which are used to detect the flow rate of hot water in the pipe 94a and the temperature of hot water to be supplied.
[0030]
A hot water supply path 80 branches off from the burner 38 of the pipe 94a. The hot water supply path 80 is connected to a bathtub water circulation path 98 described later. A hot water supply valve 82 is disposed in the hot water supply path 80, and when the hot water supply valve 82 is opened, the hot water is guided to the bathtub water circulation path 98 through the hot water supply path 80 and is filled in the bathtub 90. The The hot water supply valve 82 is controlled to be opened and closed by the control unit 60. The hot water supply path 80 is provided with a hot water filling amount sensor F2, and is used to detect the amount of hot water filled in the bathtub 90. A bathtub water thermistor T <b> 5 is disposed in the bathtub water circulation path 98, and is used to detect the temperature of hot water in the bathtub water circulation path 98.
[0031]
Next, the heating operation will be described. A heating replenishing valve 95 is disposed on a pipe 94 b branched from the hot water supply pipe 94. When the heating replenishing valve 95 is opened, hot water is guided to the heating system 51 through the pipe 94b.
[0032]
A heating circuit is connected to the heating system 51. Specifically, the common pipe 2 is connected to the heating systern 51, and the heating pump 3 is disposed in the common pipe 2. The common pipe 2 is bifurcated to form a high temperature circuit 84 and a low temperature circuit 86. Hereinafter, a general term for the common pipe 2, the high-temperature circuit 84, and the low-temperature circuit 86 is a heating circuit.
The high-temperature circuit 84 includes a pipe 84 a that passes through a high-temperature load 92 (for example, a heater or a bathroom dryer) and a pipe 84 b that bypasses the high-temperature load 92. The pipe 84a sends the hot water in the heating cistern 51 to the high temperature load 92, and returns the used hot water to the heating cistern 51 (in the direction of the arrow in the figure). The return pipe of the pipe 84a merges with the return pipe of the low-temperature circuit 86 described later. A thermal valve 85 is disposed on the pipe 84a. The thermal valve 85 is opened when the operation switch of the high temperature load 92 is operated and closed when it is turned off.
On the other hand, the pipe 84b is a pipe branched from the upstream side of the thermal valve 85, and merges with a return pipe of a low-temperature circulation path 86 described later. A heating bypass valve 83 is disposed on the pipe 84 b that bypasses the high temperature load 92. The heating bypass valve 83 is controlled to be opened and closed by the control unit 60.
[0033]
In order to heat the hot water in the high-temperature circuit 84, a burner 56 is disposed in the high-temperature circuit 84. The burner 56 is driven and controlled by the control unit 60. The temperature of the hot water in the high-temperature circuit 84 is normally controlled to be about 80 ° C. The hot water in the high-temperature circulation path 84 circulates when the heating pump 3 is driven (circulates in the arrow direction in the figure). The heating pump 3 is driven and controlled by the control unit 60.
[0034]
A recirculation circuit 88 is connected to the high temperature circuit 84. A heat exchanger 91 is disposed in the tracking circulation path 88 and merges with a return pipe of a low-temperature circulation path 86 described later. A thermal valve 89 is disposed in the tracking circulation path 88. When the thermal valve 89 is opened, hot water is guided from the high-temperature circulation path 84, and the heat of the hot water is transferred to the heat exchanger 91. . The thermal valve 89 is controlled to open and close by the control unit 60.
When pursuing bathtub water, the hot water in the bathtub 90 circulates in the bathtub water circulation path 98. The bathtub water circulation path 98 is disposed so as to pass through the heat exchanger 91 described above. Hot water in the bathtub water circulation path 98 circulates and is heated by the heat exchanger 91, so that the bathtub water is chased. A bathtub water pump 99 is disposed in the bathtub water circulation path 98. The hot water in the bathtub water circulation path 98 is circulated by driving the bathtub water pump 99. The bathtub water circulation pump 99 is driven and controlled by the control unit 60.
[0035]
The low-temperature circuit 86 is disposed so as to pass through a low-temperature load (floor heater or the like) 96. The low-temperature circulation path 86 sends the hot water in the heating cistern 51 to the low-temperature load 96 and returns the used hot water to the heating cistern 51 through two pipes to be described later.
A thermal valve 87 is provided in the forward pipe of the low-temperature circulation path 86. The thermal valve 87 is controlled to open and close by the control unit 60. The hot water in the low-temperature circuit 86 is normally controlled to be about 60 ° C.
[0036]
The return pipe of the low-temperature circulation path 86 includes a pipe 86 a that directly returns to the heating system 51 and a pipe 86 b that passes through the hot water storage tank 44 and returns to the heating system 51. These pipes 86 a and 86 b are switched by the three-way valve 12. The three-way valve 12 has one inlet 12a and two outlets 12b and 12c. The return pipe of the low-temperature circulation path 86 is connected to the inlet 12 a of the three-way valve 12. A pipe 86 a is connected to the outlet 12 b of the three-way valve 12. The other end of the pipe 86 a is connected to the heating systern 51. On the other hand, a pipe 86 b is connected to the outlet 12 c of the three-way valve 12. The pipe 86 b is a pipe that passes through the upper part of the hot water storage tank 44 without being mixed with the hot water in the hot water storage tank 44. After passing through the hot water tank 44, the pipe 86b joins the joining part 86e of the pipe 86a. Switching of the three-way valve 12 is controlled by the control unit 60. The hot water in the low-temperature circulation path 86 also circulates when the heating pump 3 is driven (circulates in the arrow direction in the figure).
[0037]
The heat stored in the hot water tank 44 can be used for the heating operation by the pipe 86b described above. When it is desired to use the heat in the hot water storage tank 44 for the floor heating operation, the outlet of the three-way valve 12 is switched to the outlet 12c. When the hot water in the pipe 86 b passes through the upper part of the hot water tank 44, the hot water is heated by the hot water in the upper part of the hot water tank 44, and the heated hot water returns to the systern 51. By this circulation, the hot water in the low-temperature circuit 86 is heated, and the heat of the hot water is transferred to the floor heater that is the low-temperature load 96. If it does in this way, the heat in hot water storage tank 44 can be used for heating operations, such as floor heating operation.
When the amount of heat stored in the hot water storage tank 44 is released, the outlet of the three-way valve 12 is switched to the outlet 12b, the heating bypass valve 83 is opened, and the pipe 84b that bypasses the high temperature load 92 (in this case, the bathroom dryer) is opened. Let In this case, the high-temperature water heated by the burner 56 is guided to the cistern 51, and the heating operation can be performed using the high-temperature hot water.
[0038]
After the heating operation is finished, when the amount of heat stored in the hot water storage tank 44 is small, the residual heat in the heating circulation path can be stored in the hot water storage tank 44 by the pipe 86b. When the temperature of the upper part of the hot water tank 44 is lower than the temperature of the hot water in the low-temperature circuit 86, the outlet of the three-way valve 12 is switched to the outlet 12c. As a result, the hot water in the low-temperature circuit 86 is guided to the pipe 86b. When the hot water in the pipe 86b passes through the hot water storage tank 44, the hot water in the hot water storage tank 44 is heated. In this way, the residual heat in the heating circuit such as the low-temperature circuit 86 can be stored in the hot water tank 44.
[0039]
Next, the configuration of the control unit 60 of the cogeneration system 10 of this embodiment will be described. FIG. 2 is a block diagram of the control unit 60. FIG. 2 shows only components characteristic of this embodiment. The control unit 60 is accommodated in the heat storage unit 15 and comprehensively controls the operation of the heat storage unit 15 and the operation of the power generation unit 20. As shown in FIG. 2, the control unit 60 includes a CPU 100, and is connected to an operation control unit 102, an operation plan unit 104, a storage unit 106, an input unit 108, and an output unit 110. The input unit 108 includes flow rate detection means (each flow rate sensor) 112, hot water temperature detection means (each thermistor) 114, power generation amount detection means 116, and power consumption detection means 118 disposed in the cogeneration system 10. It is connected. The output unit 110 is connected to the mixing unit 72, the auxiliary heat source device 50, various pumps, various three-way valves, the fuel cell 22, and the like that constitute the cogeneration system 10.
[0040]
FIG. 3 shows a relationship between power demand (shown by a solid line) required in a general household and power supplied by the cogeneration system 10 (shown by a broken line). The amount of power generation is basically adjusted to increase or decrease following the power demand. 1 kW shown in the figure is the maximum power generation in the power generation unit 20, and in a time zone exceeding this, the insufficient power is supplemented with commercial power.
Electricity demand (also called electricity load) has a peak in the morning and at night. The electric power generated at the night peak indicated by A is large and the duration is long. Therefore, if the amount of heat generated during this peak can be used effectively, the thermal efficiency is most improved. The efficiency of the cogeneration system 10 is the highest when continuously operating with maximum power generation.
[0041]
FIG. 4 shows the heat load required in a general household by a solid line. Usually, since the necessary heat energy is supplied, the required heat energy amount and the supplied heat energy amount are equal. In FIG. 4, the calorific value (heat storage amount) obtained with the power generation operation is indicated by a broken line. The required thermal energy has two peaks C and B. The night peak indicated by B is mainly due to being used for bath filling and requires more than the amount of heat obtained by power generation.
[0042]
The curves shown by the solid lines in FIGS. 3 and 4 are obtained from the past use record in the cogeneration system 10. The cogeneration system 10 is provided with means for storing the transition of the power generation amount per unit time, and the curve of FIG. 3 can be obtained. 4 can be obtained from the curve of the power generation amount per unit time in FIG. The cogeneration system 10 is provided with means for calculating and storing the amount of supplied heat energy per unit time calculated from the amount of tapping water and tapping temperature, and the solid curve in FIG. 4 can be obtained.
The curves in FIGS. 3 and 4 change from day to day. The curves in FIG. 3 and FIG. 4 are average values of the performance curves on the same day of the past month. If the current Monday is the first Monday in July, it is the average of four Monday curves in June.
[0043]
For example, the cogeneration system 10 learns four Monday curves in June, and determines the operation start time and operation end time on the first Monday in July.
(Determination of operation end time)
In the cogeneration system 10, the last heat energy supply time is determined for each unit period of 24 hours. In the previous example, the last heat energy supply time is obtained for each of the four Mondays in June. The beginning and end of the 24-hour period is assumed to be 3:00 am, which is often applied to sleep. Here, the case of supplying heat energy means that a predetermined amount or more of hot water is continuously supplied for a predetermined time or more, and does not include supplying a small amount of hot water for a short time. As a result, the end time of bathing is usually the last time when heat energy was supplied. On average, a household that takes a bath at 10:00 and goes to bed at 11:00 is supplied with the last heat energy at 10:00, and a family that finishes taking a bath at midnight and goes to bed at midnight is supplied with the last heat energy at midnight. I understand that.
In the cogeneration system 10, the operation is stopped at the time when the thermal energy is finally supplied. In the case of FIG. 4, the operation of the cogeneration system 10 is terminated at time D. Since no heat is generated thereafter, it is possible to minimize the use of the generated heat by bringing it to the next day.
[0044]
(Determination of operation start time)
In the cogeneration system 10, the operation start time E is obtained as follows.
(1) The operation start time E is assumed.
(2) Pay attention to changes in the amount of power generated per unit time after the time E.
(3) The transition of the heat generation amount obtained from the power generation amount per unit time after the time E is calculated (this is indicated by a broken line in FIG. 4).
(4) The total calorific value obtained by accumulating the calorific value per unit time from the time E to the operation end time D is calculated (the area indicated by the hatch in FIG. 4 is calculated).
(5) Separately, the total amount of heat required for the unit period of 24 hours is calculated (the area surrounded by the graph and the horizontal axis shown in FIG. 4 is calculated).
(6) A time E at which (4) and (5) described above are equal is obtained.
(7) The time thus obtained is defined as the operation start time E.
The logic is the time E retroactive from the operation end time D, and the total heat storage energy amount (hatch area) calculated from the total power supply amount from the retroactive time E to the operation end time D is 24. This is nothing but specifying the time E that is equal to the average amount of the total heat energy supply amount in the unit period in units of time (the area surrounded by the graph and the horizontal axis in FIG. 4).
[0045]
The above processing procedure will be described with reference to the flowchart of FIG. FIG. 5 is a processing procedure diagram showing an operation method.
As shown in FIG. 5, first, in step S10, the heat energy supply amount per unit time on the same day within the past month is specified. The thermal energy supply amount specified by this processing is a graph indicated by a solid line in FIG. Proceeding to step S12, the end of the phenomenon of supplying a predetermined flow rate or more for a predetermined time or more is specified. By this process, the operation end time (time D shown in FIG. 4) is set. Proceeding to step S14, the total required heat energy amount for 24 hours is calculated. This total required heat energy amount is obtained by integrating the solid line graph of FIG. 4 obtained in step S10. Proceeding to step S16, the power generation amount per unit time on the same day within the past month is specified. The power generation amount specified by this processing is a graph indicated by a solid line in FIG. Proceeding to step S18, the heat generation amount per unit time is specified from the power generation amount per unit time. Proceeding to step S20, the operation start time is such that the heat generation amount per unit time from the operation start time to the operation end time set in step S12 becomes the total required heat energy amount for 24 hours obtained in step S14. Is set.
Proceeding to step S22, it is determined whether or not the time from the operation start time set in step S20 to the previously set operation end time is equal to or greater than a preset upper limit time. If this operation continuation time does not exceed the upper limit time (if NO), processing is performed so that the operation is started at the operation start time set in step S20. If the operation continuation time is equal to or greater than the upper limit time (if YES), the operation start time is corrected so that the operation continuation time does not exceed the upper limit time by proceeding to step S24 and delaying the operation start time. Processing is performed so that the operation is started at the operation start time.
[0046]
In the present embodiment, the past use record is learned, and it is planned to continue the operation of the cogeneration system until the time when the heat energy is estimated to be supplied last. In addition, the operation is started at a time when the required heat energy for one day will be stored by that time. Therefore, if it goes according to schedule, when the operation is continued until the time when the heat energy is finally supplied, the stored hot water should be used. However, if the demand for electric power increases on the day, the amount of generated heat also increases, and heat energy equivalent to the total heat energy required for one day may end up being stored early.
In this case, the schedule for continuing the operation until the time when the heat energy is estimated to be supplied last is changed, and the operation is stopped when the necessary amount of heat is stored. After that, commercial power will be used, but it is more reasonable to use commercial power because it corresponds to a higher efficiency. The advantages of cogeneration systems can be fully utilized.
[0047]
The total amount of heat energy that can be stored in the heat storage means may be stored. In this case, by referring to the means storing the heat energy supply amount per unit time over a predetermined period in the past, it becomes possible to specify the time when the heat can be stored next.
In the cogeneration system 10, when the entire amount of heat energy that can be stored in the heat storage means has been stored, a program is provided that specifies the time when the next heat storage is possible. In addition, a program is provided to calculate the energy when the cogeneration system operation is continued until that time. In this program, energy is calculated by multiplying the amount of heat released per unit time of the cogeneration system by time. Furthermore, a program for calculating energy required for preparation when the operation of the cogeneration system is temporarily stopped and resumed is prepared. The cogeneration system 10 has a program for comparing the two and adopting the more advantageous one. When the total amount of heat energy that can be stored in the heat storage means is stored, and it is more advantageous to continue the operation than to temporarily stop the operation and restart it, cogeneration is performed while the heat is dissipated by the radiator 28 disposed in the power generation unit. The operation of the system 10 is continued.
[0048]
The above processing procedure will be described with reference to the flowchart of FIG. FIG. 6 is a processing procedure diagram showing an operation method.
When the operation of the cogeneration system is started in step S40, the process proceeds to step S42, and it is determined whether or not the necessary heat amount for one day is stored. If the required amount of heat for one day is stored (if YES), the process proceeds to step S44 and the operation of the cogeneration system is terminated. If the required amount of heat for one day is not stored (if NO), the process proceeds to step S46.
In step S46, it is determined whether or not the entire amount of heat energy that can be stored in the hot water storage tank has been stored. If the total amount of heat energy that can be stored is not stored (if NO in step S46), the processes in steps S42 and S46 are repeated. If the total amount of heat energy that can be stored is stored (if YES in step S46), the process proceeds to step S48 to specify the next time when the hot water is predicted. Proceeding to step S50, the energy is calculated when the operation is continued until the next time when the hot water is predicted. Moreover, it progresses to step S52 and calculates | requires the energy at the time of restarting operation | movement until the time when next hot water discharge is estimated, and restarting. And it progresses to step S54 and the energy at the time of the driving | operation continuation obtained by step S50 is compared with the energy at the time of the driving | operation stop obtained by step S52. Next, if it is more advantageous to continue the operation until the time when the hot water is predicted (if YES in step S54), the operation returns to step S42 and the operation is continued. Next, if it is more advantageous to temporarily stop and restart the operation until the time when the hot water is predicted (if NO in step S54), the process proceeds to step S56, the operation is temporarily stopped, and the process proceeds to step S58. The hot water is prepared for the hot water time, and when the hot water time is reached, the flow returns to step S42 to restart the operation.
[0049]
The cogeneration system 10 is provided with an upper limit time for the operation continuation time per day. When the time from the operation start time specified by the technique to the specified operation end time exceeds the operation continuation upper limit time, the operation start time is delayed so as not to exceed the upper limit time.
A method of delaying the operation start time rather than advancing the operation end time is extremely preferable because the upper limit time can be observed while driving around a period when the efficiency of the cogeneration system is high.
[0050]
Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
In addition, the technical elements described in the present specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a cogeneration system according to an embodiment.
FIG. 2 is a block diagram of a control unit and its surroundings.
FIG. 3 is a graph showing changes over time in required electric energy and electric power that can be generated.
FIG. 4 is a graph showing temporal changes in required heat amount and stored heat amount.
FIG. 5 is a processing procedure diagram 1 showing an operation method.
FIG. 6 is a processing procedure diagram 2 showing an operation method.
[Explanation of symbols]
4: Power generation heat recovery pipe, 4a: Outward pipe, 4b: Return pipe
6: Pump for heat recovery
10: Cogeneration system
12: Three-way valve, 12a: Inlet, 12b: Outlet, 12c: Outlet
15: Thermal storage unit
20: Power generation unit
22: Fuel cell
30: Reformer
38: Burner
40: Use of hot water
44: Hot water storage tank
50: Auxiliary heat source machine for hot water heater
52: First hot water pipe
60: Control unit
64: water supply pipe, 64a: first water supply pipe, 64b: second water supply pipe
72: mixing unit, 72a: hot water inlet, 72b: cold water inlet, 72c: outlet
76: Second hot spring pipe
90: Bathtub
94: Hot water supply pipe, 94a: Pipe, 94b: Pipe
98: Bathtub water circuit
99: Pump for bathtub water
100: CPU
102: Operation control means
104: Operation planning means
106: Storage means
108: Input unit
110: Output unit
112: Flow rate detection means
114: Hot water temperature detection means
T1: Water supply thermistor
T2: First hot spring thermistor
T3: Second hot spring thermistor
T4: Hot water supply thermistor
T5: Bathtub thermistor
F1: Hot water supply sensor
F2: Hot water filling amount sensor
F3: Mixed water flow sensor

Claims (8)

It is a cogeneration system that generates electricity according to power demand, stores the heat generated during power generation, and supplies the stored thermal energy when necessary.
Means for storing the amount of heat energy supplied per unit time in the past ;
Means for determining the last heat energy supply time for each unit period in units of 24 hours from the past heat energy supply amount for each unit time;
A means for specifying an average time of the last heat energy supply time for each unit period and setting it as a scheduled operation end time ;
A cogeneration system having means for terminating the operation of the cogeneration system at a scheduled operation end time . The cogeneration system according to claim 1, wherein when the average time of the last heat energy supply time for each unit period is specified, the last heat energy supply time for each unit period on the same day in the past is averaged. Means for storing the power supply amount per unit time in the past ;
It means for calculating a total heat energy amount for each unit period from heat energy supply per past unit time,
Means for determining the average amount of total heat energy supply per unit period;
A time when the retroactive from the operation end scheduled time, the total heat storage amount of energy is calculated from the total amount of power supplied from the retroactive time until the operation end scheduled time, the average amount of total thermal energy supply per unit of time A means for identifying equal times and setting the scheduled operation start time ;
The cogeneration system according to claim 1 or 2, further comprising means for starting operation of the cogeneration system at a scheduled operation start time . 4. The cogeneration system according to claim 3, wherein when the average amount of the total heat energy supply amount for each unit period is specified, the total heat energy supply amount for each unit period on the same day in the past is averaged. The cogeneration system according to claim 3 or 4, further comprising means for delaying the scheduled operation start time so as not to exceed the maximum operation continuation time when the time from the planned operation start time to the planned operation end time exceeds the maximum operation continuation upper limit time. . Means for specifying the time when heat can be stored next from the amount of heat energy supplied for each past unit time when the total amount of heat energy that can be stored in the heat storage means is stored;
Compare the balance when operating the cogeneration system until the specified time and the balance when stopping the cogeneration system and restarting at the specified time. The cogeneration system according to any one of claims 1 to 5, further comprising means for determining one of them. It is a method of generating an operation plan of a cogeneration system that generates electricity according to power demand, stores heat generated during power generation, and supplies the stored thermal energy when necessary.
Storing the amount of heat energy supplied per unit time in the past;
Determining the last heat energy supply time for each unit period in units of 24 hours from the past heat energy supply amount for each unit time;
Identifying the average time of the last heat energy supply time for each unit period, and setting the scheduled operation end time;
An operation plan creation method for a cogeneration system having a step of creating an operation plan for terminating the operation of the cogeneration system at a scheduled operation end time. Storing a power supply amount for each past unit time;
Calculating the total amount of heat energy supplied per unit period from the amount of heat energy supplied per unit time in the past;
Identifying an average amount of total heat energy supply per unit period;
This is a retroactive time from the scheduled operation end time, and the total heat storage energy calculated from the total power supply from the retroactive time to the planned operation end time is the total heat energy for each unit period. Identifying a time that is equal to the average amount of energy supplied and setting the scheduled operation start time;
8. The operation plan creation method for a cogeneration system according to claim 7, further comprising a step of creating an operation plan for starting operation of the cogeneration system at a scheduled operation start time.

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