WO2013157253A1

WO2013157253A1 - Fuel cell system

Info

Publication number: WO2013157253A1
Application number: PCT/JP2013/002580
Authority: WO
Inventors: 貴彬藤川; 佳典岡; 洋永里
Original assignee: パナソニック株式会社
Priority date: 2012-04-16
Filing date: 2013-04-16
Publication date: 2013-10-24
Also published as: JP2015122139A

Abstract

A fuel cell system, provided with: a fuel cell unit (10), which is supplied with a fuel gas and which performs power generation accompanied by generation of heat and supplies electrical power and heat; a hot water storage unit (11) provided with a hot water storage tank (103) for storing, as hot water, heat supplied by the fuel cell unit; a heat discharge part (12) for discharging heat stored in the hot water storage tank; a heat storage amount detector (104) for detecting the amount of heat stored in the hot water storage tank; and a controller (12) for discontinuing generation of power by the fuel cell unit when the amount of heat stored in the hot water storage tank reaches an upper limit value. When the heat storage amount detector detects that the amount of heat stored is equal to or greater than a first predetermined heat storage amount, the controller calculates, on the basis of the predicted usage amount of heat in the hot water tank and the amount of electrical power supplied by the fuel cell unit, the water, electricity, and gas usage fees chargable to the system user, and performs control, on the basis of the calculated usage fees, as to whether or not to discharge heat through the heat discharge part.

Description

Fuel cell system

The present invention relates to a fuel cell system including a fuel cell unit that supplies electric power and heat, and a hot water storage unit that includes a hot water storage tank that stores heat supplied from the fuel cell unit as hot water.

2. Description of the Related Art Conventionally, a fuel cell and a heat exchanger for exchanging heat between exhaust gas from the fuel cell and water, a fuel cell unit that supplies electric power and heat, and heat supplied from the fuel cell unit are heated. There has been a fuel cell system composed of a hot water storage unit equipped with a hot water storage tank. However, if the temperature of the water in the hot water storage tank becomes higher than a predetermined temperature, there is a problem that heat cannot be exchanged between the exhaust gas from the fuel cell and the water in the hot water storage tank, and the fuel cell system cannot generate power. In order to solve this problem, in this type of fuel cell system, for example, configurations shown in FIGS. 18 and 19 are disclosed (see, for example, Patent Documents 1 and 2).

The fuel cell system shown in FIG. 18 shown in Patent Document 1 will be described below.

The fuel cell system shown in FIG. 18 includes a fuel cell device (power generation unit) including a fuel cell 1 and a heat exchanger 5 for exchanging heat between the exhaust gas from the fuel cell 1 and water, and after heat exchange. A hot water storage tank 17 for storing water, a circulation pipe 16 for circulating water between the heat exchanger 5 and the hot water storage tank 17, and a drainage device for draining water stored in the hot water storage tank 17. The temperature sensor 19 for measuring the temperature of the water circulated between the heat exchanger 5 and the hot water storage tank 17, the water storage device 25 for storing the water in the hot water storage tank 17, and the temperature sensor. Control for controlling the operation of the drainage device so that the water stored in the hot water storage tank 17 is supplied to the water storage device 25 when the temperature of the water to be stored is measured above the first predetermined temperature for a predetermined time. And a device 13. It is a fuel cell system. In such a fuel cell system, when the temperature of the water measured by the temperature sensor 19 is measured at a first predetermined temperature or higher continuously for a predetermined time, the water storage device 25 is automatically supplied. By controlling the operation of the drainage device, hot water generated by heat exchange can be used efficiently, and a fuel cell system with improved operating efficiency (total efficiency) can be obtained.

In addition, the drainage device is provided with an external drain pipe 21 having a valve 22 for draining water from the hot water storage tank 17 to the outside, and a water storage device supply having a valve 24 for supplying water from the hot water storage tank 17 to the water storage device. And a tube 23. In such a fuel cell system, the water storage provided with the external drain pipe 21 provided with the valve 22 for draining the water of the hot water storage tank 17 outside, and the valve 24 for supplying the water of the hot water storage tank to the water storage device. Since the apparatus supply pipe 23 is provided, it is possible to easily control whether the water in the hot water storage tank is drained to the outside or supplied to the water storage apparatus 25.

Next, the fuel cell system of FIG. 19 shown in Patent Document 2 will be described.
The fuel cell system shown in FIG. 19 includes a hot water storage tank 31, tank lower hot water temperature detecting means 43 for detecting the temperature of hot water in the lower part of the hot water storage tank 31, one end communicating with the lower part in the hot water storage tank, and the other end in the hot water storage tank. A heat recovery pipe 32 having a heat recovery heat exchanger 40 for recovering exhaust heat during power generation of the fuel cell in the middle of communication with the upper part, a hot water supply pipe 36 for supplying hot water in the upper part of the hot water storage tank 31, and a hot water storage tank 31 is connected to the lower part of the hot water storage tank 31 so as to keep the hot water in the hot water tank 31 at a predetermined amount, and the hot water in the hot water storage tank 31 is introduced from the lower part of the hot water tank 31 and returned to the upper part of the hot water tank 31. A hot water tank circulating pump 33 for circulating hot water in the heat recovery pipe 32 and a remote controller 42 having a notification means are provided. In particular, when the temperature of the tank lower hot water temperature detection means 43 exceeds a predetermined temperature lower than the system stop temperature at which the system needs to be stopped, the notification means performs a hot water supply operation from the hot water supply pipe 36 to the user within a predetermined time. It is configured to prompt you. In such a fuel cell system, the use of hot water in the hot water storage tank 31 (hot water supply) is small, and the temperature of the hot water in the lower part of the hot water storage tank 31 rises, so that the heat dissipation efficiency of the fuel cell deteriorates, If there is no use of hot water in the hot water storage tank 31 (hot water supply), the temperature of the hot water in the lower part of the hot water storage tank 31 will soon rise to reach the system stop temperature at which the system needs to be stopped and the system will stop. The notifying means prompts the user to perform the hot water supply operation from the hot water supply pipe 36 within a predetermined time, so that the user is more likely to perform the hot water supply operation from the hot water supply pipe 36 within the predetermined time. If the user performs hot water supply operation from the hot water supply pipe 36, water is supplied to the lower part of the hot water storage tank 31 as much as the hot water in the hot water storage tank 31 is reduced. Since the temperature of the water is lowered, it can be avoided to stop the power generation.

JP 2011-49020 A JP 2011-174626 A

However, in the conventional configuration shown in FIG. 18, the temperature of the water measured by the temperature sensor 19 is continuously measured for a predetermined time at the first predetermined temperature or higher, and the water level of the water storage device 25 is high, and the hot water storage tank 17 When the water cannot be supplied to the water storage device 25, the hot water in the hot water storage tank 17 is drained to the outside. In this case, the hot water in the hot water storage tank 17 is drained without taking into consideration the economic effect such as the water charge that is wasted due to the hot water drainage of the hot water storage tank 17 and the gas charge that is increased as power generation continues. Therefore, in some cases, there is a problem that the user of the fuel cell system is economically damaged. Furthermore, the provision of the water storage device 25 in the fuel cell cogeneration system in order to reduce the water in the hot water storage tank 17 that drains to the outside also causes an increase in the installation area or the installation volume, thus reducing the installation opportunity in the market. It also has the problem of being connected to

In the conventional configuration shown in FIG. 19, when the user does not perform the hot water supply operation and the temperature of the hot water storage tank 31 exceeds the system stop temperature, the fuel cell system is stopped and the power generation is disabled. In the power generation disabled state, it is necessary to purchase insufficient power from the system power supply, and thus there is a problem that the economic merit by using the fuel cell system cannot be obtained.

This invention solves the conventional subject, and it aims at providing the fuel cell system which can exhaust the heat of a hot water storage tank, considering economical efficiency.

In order to solve the conventional problems, a fuel cell system according to the present invention generates power with heat generated by supplying fuel gas, and supplies a fuel cell unit for supplying electric power and heat, and heat supplied from the fuel cell unit. Hot water storage unit equipped with a hot water storage tank that stores hot water, an exhaust heat unit that exhausts heat stored in the hot water storage tank, a heat storage amount detection unit that detects the amount of heat stored in the hot water tank, and the heat storage amount of the hot water tank A control unit that stops the power generation of the fuel cell unit when reaching the value, and when the control unit detects that the heat storage amount detection unit is equal to or greater than the first predetermined heat storage amount, the amount of power supplied by the fuel cell unit Whether or not the system user's water, electricity, and gas usage charges are calculated based on the prediction of heat usage in the hot water storage tank, and whether or not heat is discharged by the exhaust heat unit based on the calculated usage charges Control That.

As a result, if the temperature of water supplied from the hot water storage tank to the fuel cell unit is high and it is necessary to exhaust heat from the hot water storage tank in order to avoid the fuel cell system from being in a power generation disabled state, The sum of water charges, electricity charges, and gas charges used when exhausting heat is the sum of water charges, electricity charges, and gas charges used when stopping the power generation of the fuel cell system without exhausting heat from the hot water storage tank. Only when it is cheaper can it be drained.

In the fuel cell system of the present invention, when the temperature of the hot water storage tank rises and the hot water storage tank does not perform exhaust heat, the fuel cell system becomes incapable of generating power. Reduce the economic burden of water charges, electricity charges, and gas charges used by system users by exhausting heat from the hot water storage tank and generating power or shutting down the system without exhausting heat so that the total gas charge is reduced. Can do. Moreover, since this can reduce the economic loss due to the exhaust heat of the hot water storage tank, it is not necessary to provide a water storage device, leading to an increase in installation opportunities in the market.

1 is a block diagram of a fuel cell system in Embodiment 1 of the present invention. FIG. It is a block diagram which shows the structure of the controller of the fuel cell system of FIG. It is a flowchart which shows the processing operation of the controller of FIG. It is a block diagram which shows the structure of the controller of the fuel cell system in Embodiment 2 of this invention. It is a flowchart which shows the processing operation of the controller of FIG. It is a graph which shows an example of the demand forecast of a fuel cell system in case the continuation of electric power generation is obtained in the processing operation of FIG. 5, and a user burden. It is a graph which shows an example of the demand forecast of a fuel cell system when a power generation stop is obtained in the processing operation of FIG. 5, and a user burden. It is a graph which shows an example of the user burden amount accompanying the demand fluctuation of a fuel cell system, when it is estimated that continuation of power generation is obtained in the processing operation of FIG. It is a flowchart which shows the processing operation of the fuel cell system in Embodiment 3 of this invention. It is a flowchart which shows the processing operation of the fuel cell system in Embodiment 4 of this invention. It is a flowchart which shows the processing operation of the fuel cell system in Embodiment 5 of this invention. It is a flowchart which shows the processing operation of the fuel cell system in Embodiment 6 of this invention. It is a flowchart which shows the processing operation of the fuel cell system in Embodiment 7 of this invention. It is a flowchart which shows the processing operation of the fuel cell system in Embodiment 8 of this invention. It is a flowchart which shows the processing operation of the fuel cell system in Embodiment 9 of this invention. It is a flowchart which shows the processing operation of the fuel cell system in Embodiment 10 of this invention. It is a block diagram of the fuel cell system in Embodiment 11 of this invention. 1 is a block diagram of a fuel cell system of Patent Document 1. FIG. 2 is a block diagram of a fuel cell system of Patent Document 2. FIG.

A fuel cell system according to a first aspect of the present invention includes a fuel cell unit that supplies power and heat by supplying fuel gas and generates heat, and a hot water storage tank that stores the heat supplied from the fuel cell unit as hot water. A hot water storage unit, a heat exhaust section that exhausts heat stored in the hot water storage tank, a heat storage amount detection section that detects the heat storage amount of the hot water storage tank, and a fuel cell unit A controller that stops power generation, and the controller uses the amount of power supplied by the fuel cell unit and heat of the hot water storage tank when the heat storage amount detection unit detects that the first heat storage amount is equal to or greater than the first predetermined heat storage amount. Based on the amount prediction, the system user calculates usage charges for water, electricity, and gas, and controls whether or not to exhaust heat by the exhaust heat unit based on the calculated usage charges.

As a result, when the amount of heat stored in the hot water storage tank is equal to or greater than the first predetermined amount of stored heat, the system user's usage fees for water, electricity, and gas are calculated based on the prediction of the amount of supplied power and the amount of hot water. Therefore, it is possible to select one of exhausting heat from the hot water storage tank to generate power, or stopping the system without exhausting heat, and the economic burden on the system user can be reduced. Moreover, since it is possible to reduce the economic loss due to the exhaust heat of the hot water storage tank, it is not necessary to provide a water storage device, which is useful for increasing installation opportunities in the market. Here, the exhaust heat unit may exhaust heat by, for example, draining hot water stored in the hot water storage tank, or may exhaust heat by dissipating heat of the hot water storage tank by a radiator. When heat is radiated by the radiator, water charges are not generated unlike the case of draining hot water, so that the economic burden on the system user can be further reduced.

In a second aspect based on the first aspect, the heat storage amount detection unit detects the temperature of hot water in the hot water storage tank, and the control unit indicates that the heat storage amount detection unit is equal to or higher than the first predetermined temperature. When detected, a prediction unit that predicts the amount of power and hot water supply used by the fuel cell unit in a predetermined period, and the heat exhausted by the heat exhaust unit in a predetermined period based on the prediction in the predetermined period, Calculate the sum of the usage charges for water, electricity, and gas, and the usage fee calculation unit that calculates the sum of the usage charges for water, electricity, and gas when exhaust heat is not used for a specified period Compare the usage fee when the exhaust heat is used and the usage fee when the exhaust heat is not performed.If the usage fee when the exhaust heat is exhausted is lower than the usage fee when the exhaust heat is not exhausted, An exhaust heat control unit that heats Obtain.

As a result, when the hot water in the hot water storage tank is in a high temperature state, the system user's water supply, electricity, In addition, when the sum of the gas usage charges is reduced, the hot water storage tank is exhausted, so that the economic burden on the system user can be reduced. Here, the predetermined period may be, for example, the time from when the fuel cell system is stopped until the power generation state is restored.

In a third aspect based on the second aspect, the control unit controls the exhaust heat so that the temperature detected by the heat storage amount detection unit is equal to or lower than a second predetermined temperature lower than the first predetermined temperature. Thereby, since the temperature of the hot water in the hot water storage tank can be lowered to a temperature at which the system can be continued, it is possible to avoid the system from being stopped.

In a fourth aspect based on the second aspect, the control unit calculates an amount of heat exhausted by the exhaust heat unit based on prediction of an amount of electric power and hot water supply usage that the fuel cell unit supplies in a predetermined period, and calculates the calculation It controls so that the amount of exhausted heat is exhausted. As a result, the temperature of the hot water in the hot water storage tank can be efficiently lowered to a temperature at which the system can be continued based on the prediction of the amount of supplied power and the amount of hot water used, so that the system can be prevented from stopping.

In a fifth aspect based on the fourth aspect, the control unit performs control so that the calculated exhaust heat amount is divided and exhausted. As a result, even if the prediction of the amount of exhaust heat calculated by the control unit deviates due to unpredictable use of water, electricity, or gas, the amount is exhausted by dividing the amount and exhausting waste heat due to mispredictions. Therefore, it is useful for reducing the economic burden on the system user.

The sixth invention is the amount obtained by selling the electric power generated by the fuel cell unit from the sum of the usage charges for water, electricity and gas when exhaust heat is exhausted in the second invention. When the value obtained by subtracting is cheaper than when the exhaust heat is not performed, the exhaust heat may be performed. As a result, the exhaust heat of the hot water storage tank can be controlled so that the sum of the water usage fee, the electricity usage fee considering the sold electricity fee, and the gas usage fee can be reduced. This is useful for reducing the economic burden on system users in areas where power can be sold.

According to a seventh aspect, in the second aspect, the control unit is obtained by using the electric power generated by the fuel cell unit from the sum of usage charges of water, electricity, and gas when exhaust heat is performed. If the amount of money after subtracting the subsidy is cheaper than when the exhaust heat is not performed, the exhaust heat may be performed.

As a result, the exhaust heat of the hot water storage tank can be controlled so that the sum of the water usage fee, the electricity usage fee considering the subsidies for using the generated power, and the gas usage fee can be reduced. This is useful for reducing the economic burden on system users in areas where subsidies can be obtained by using the power generated by the unit.

In an eighth aspect based on the second aspect, the controller is configured to reduce the amount of heat loss in the hot water storage tank that is wasted due to exhaust heat in the sum of usage charges for water, electricity, and gas when exhaust heat is performed. If the amount of money is less than when the exhaust heat is not performed, the exhaust heat may be performed.

As a result, the exhaust heat of the hot water storage tank is controlled so that the sum of the usage fee of the gas, considering the exhaust gas used for the amount of heat that is wasted due to the waste heat of the hot water storage tank, electricity usage fee, and hot water storage tank is reduced. Therefore, it is useful for reducing the economic burden on the system user and improving the accuracy when calculating the economic burden.

A ninth invention further comprises a power storage unit for storing the generated power of the fuel cell unit according to the second invention, wherein the control unit further determines the usage charges of water, electricity and gas when exhaust heat is performed. If the amount obtained by subtracting the amount of reduction in the electricity usage fee obtained by storing electricity in the electricity storage unit from the sum is lower than when the exhaust heat is not performed, the exhaust heat may be performed.

As a result, the exhaust heat of the hot water storage tank is controlled so that the total amount of electricity and gas usage considering the use of water supply, stored electricity is reduced, so the system usage when the fuel cell system is equipped with a storage unit This is useful for reducing the economic burden on the user.

In a tenth aspect based on any one of the first to ninth aspects, the control unit controls to restart power generation while the fuel cell unit is stopped, and controls to exhaust heat in the exhaust heat unit. May be.

As a result, even when the fuel cell system is stopped, the exhaust heat of the hot water storage tank is controlled so that the sum of the usage charges for water, electricity and gas is reduced, which is useful for reducing the economic burden on the system user. .

(Embodiment 1)
Hereinafter, the fuel cell system according to Embodiment 1 of the present invention will be described in detail.

FIG. 1 is a block diagram of a fuel cell system according to Embodiment 1 of the present invention.

As shown in FIG. 1, the fuel cell system generates power with heat generation by being supplied with fuel gas, and stores the fuel cell unit 10 that supplies power and heat, and the heat supplied from the fuel cell unit 10 as hot water. A hot water storage unit 11 having a hot water storage tank 103, a heat removal unit 12 that exhausts heat stored in the hot water storage tank 103, a heat storage amount detection unit 104 that detects a heat storage amount of the hot water storage tank 103, and a heat storage amount of the hot water storage tank 103 Includes a controller 13 that stops the power generation of the fuel cell unit 10 when the value reaches the upper limit.

The fuel cell unit 10 is supplied with fuel gas, generates electricity with heat generation, supplies power and heat, and a heat exchanger for exchanging heat between exhaust gas and water from the fuel cell 100. 101 and a hot water storage circulation pump 102 for circulating the water in the hot water storage tank 103 in a heat recovery pipe 110 having a heat exchanger 101. The fuel cell unit 10 supplies power to a power load (not shown), and supplies heat to the water in the hot water storage tank 103 using the heat exchanger 101.

The hot water storage unit 11 includes a hot water storage tank 103 that stores heat supplied from the fuel cell unit 10 through the heat exchanger 101 as hot water, a heat storage amount detection unit 104 that detects a heat storage amount of the hot water storage tank 103, and a hot water supply pipe 108. A hot water heater 105 that performs a hot water supply operation of the hot water storage tank 103 and a water heater 106 that performs a water supply operation of the hot water storage tank 103 from the water supply pipe 109 are provided, and the hot water in the hot water storage tank 103 is kept at a predetermined amount. In the present embodiment, the heat storage amount detection unit 104 is configured by a temperature detector that detects the temperature of hot water in the hot water storage tank 103.

The exhaust heat unit 111 exhausts the heat stored in the hot water storage tank 103. Since the amount of heat stored in the hot water storage tank 103 decreases due to the exhaust heat, it is possible to avoid stopping the fuel cell system. In the present embodiment, the exhaust heat unit 111 is configured by a drain that drains the hot water in the hot water storage tank 103 from the drain pipe 107 provided to throw away the hot water in the hot water storage tank 103 to the outside.

The controller 13 is configured to receive data related to the temperature of the hot water in the hot water storage tank 103 detected by the temperature detector 104, and the temperature detector 104 determines that the temperature of the hot water in the hot water storage tank 103 is the first predetermined temperature. When it is detected that the above is true, the system user's usage charges for water, electricity, and gas are calculated based on the prediction of the amount of power supplied by the fuel cell unit 10 and the amount of heat used in the hot water storage tank 103. Based on the calculated usage fee, it is controlled whether or not the drainage by the drainage device 12 is performed.

FIG. 2 is a block diagram showing the configuration of the controller 13 of FIG. As shown in FIG. 2, the controller 13 includes a demand prediction unit 131, a charge calculation unit 132 that calculates a user's burden, a drainage control unit 133 that determines whether or not to drain, and a storage unit 134. Prepare. For example, the controller 13 includes a calculation device such as a microcontroller or PLC (programmable logic controller), and the demand prediction unit 131, the charge calculation unit 132, the drainage control unit 133, and the like are incorporated in the calculation device. The storage unit 134 includes an internal memory such as a microcontroller. The storage unit 134 stores information such as current and past demand data, an operation plan of the fuel cell system, and the like.

When the temperature detector 104 detects that the temperature detector 104 is equal to or higher than the first predetermined temperature, the demand prediction unit 131 predicts the amount of power and hot water usage used by the fuel cell unit 10 in a predetermined period.

The charge calculation unit 132 calculates the sum of the usage charges of water, electricity, and gas when drainage is performed by the drainage device 12 during a predetermined period based on the predicted amount predicted by the demand prediction unit 131, and the predetermined amount Calculate the sum of usage charges for water, electricity, and gas when there is no drainage during the period.

The drainage control unit 133 compares the usage fee when draining is performed with the usage fee when draining is not performed, and the usage fee when draining is lower than the usage fee when draining is not performed. In case, drain.

Hereinafter, the processing operation of the controller 13 for controlling the drainage of the fuel cell system according to the first embodiment will be described with reference to FIGS.

FIG. 3 is a flowchart showing the processing operation of the controller 13 that controls the drainage of the fuel cell system according to Embodiment 1 of the present invention.

First, in the processing operation of the controller 13 that controls the drainage of the fuel cell system according to the first embodiment, the controller 13 requests the drainer 12 to drain until the temperature of the temperature detector 104 falls to a predetermined temperature. This will be described with reference to FIGS.

When the temperature of the hot water in the hot water storage tank 103 detected by the temperature detector 104 exceeds the first predetermined temperature lower than the system stop temperature at which the system needs to be stopped (step in FIG. 3) The branch Y) of S20 predicts the amount of power and hot water usage used by the fuel cell system during the predetermined period α. Here, in the present embodiment, for example, the predetermined period α is set to a time from when the fuel cell system is stopped until the power generation state is resumed. In addition, for example, prediction based on past data may be used for prediction of the amount of power supplied by the fuel cell system and use of hot water, for example, the current amount of power and use of hot water.

Next, the charge calculation unit 132 continues the system operation in which the temperature of the temperature detector 104 is lower than the first predetermined temperature in the predetermined period α based on the prediction of the amount of power supplied by the fuel cell system and the amount of hot water used. When the power generation is continued by draining the hot water storage tank 103 so that the temperature falls to the second predetermined temperature possible, and when the system is shut down without draining during the predetermined period α, the water charge, electricity charge, gas in each case The sum of the charges is calculated (step S21 in FIG. 3).

After that, the drainage control unit 133 compares the usage fee when draining is performed with the usage fee when draining is not performed based on the calculation result, and the usage fee when draining is not drained. In the case where the price is lower than the usage fee, the drainage is performed so that the temperature of the temperature detector 104 falls below the first predetermined temperature to a second predetermined temperature at which the system operation can be continued. When the drainage control unit 133 determines that it is cheaper to drain the hot water storage tank 103 and continue power generation (branch Y in step S22 in FIG. 3), the drainage control unit 133 transmits a signal requesting drainage to the drainer 12 (FIG. 3). Step S23). Then, when the temperature of the temperature detector 104 falls to the second predetermined temperature (YES in step S24 in FIG. 3), the drain control unit 133 stops the signal requesting drain that has been transmitted to the drain 12 (Step S25 in FIG. 3). On the other hand, the drainage control unit 133 transmits a signal to stop the power generation to the fuel cell unit 10 when it is determined in step 22 that the hot water storage tank 103 is drained and power generation is continued (highly, not cheap). (NO in step S22 of FIG. 3). As a result, in the fuel cell system during power generation, the hot water storage tank 103 is drained so that the sum of water charges, electricity charges, and gas charges used by system users is reduced and power generation is continued, or the system is not drained. Since it can be stopped, the economic burden on the system user can be reduced.

Also, this can reduce the economic loss due to the drainage of the hot water storage tank, so there is no need to provide a water storage device, which is useful for increasing installation opportunities in the market. Here, the water charge which increases with drainage calculated in step S21 of FIG. 3 will be described. The water charge that increases with drainage is determined by the amount drained when the temperature of the temperature detector 104 falls to the second predetermined temperature, but the amount of drainage depends on the temperature of the water supplied from the water supply 106. Therefore, for example, if a certain amount of water is drained, a second water temperature detector (not shown) that calculates an increasing water charge or measures the temperature of the supplied water at or near the water supply 106 or the water supply pipe 109 is provided. It is also possible to calculate the drainage amount of the hot water storage tank 103 based on the temperature detected by the second temperature detector and calculate the increasing water charge. Further, when calculating the electricity charge or gas charge (step S21 in FIG. 3), the unit power input by the user of the fuel cell system, the charge per unit gas, or the unit power obtained from the net or the like, per unit gas You may calculate based on the forecast using the charge. In addition, the calculation method of the water bill, the electricity bill, and the gas bill in the first embodiment is not limited to the first embodiment.

In the fuel cell system shown in the first embodiment, in the hot water storage tank 103, when a temperature profile (hereinafter referred to as “lamination”) of the hot water stored in the hot water stored in the hot water increases from bottom to top is generated. As shown in FIG. 1, it is desirable that the temperature detector 104 and the heat recovery pipe 110 are located below the hot water storage tank 103. Thereby, hot water with a low temperature advantageous for heat exchange can be supplied to the heat exchanger 101. Further, in the case where a stack is created in the hot water storage tank 103, it is desirable that the drainage device 12 discharges hot water from the upper part of the hot water storage tank 103 as shown in FIG. 1. Accordingly, hot water having a high temperature in the hot water storage tank 103 can be discarded, which is advantageous for lowering the temperature of the hot water in the hot water storage tank 103, and is useful for reducing water bills by reducing the amount of drainage.

The drainer 12 is configured to drain the hot water in the hot water storage tank 103 through a drain pipe branched from the branch point (point A in FIG. 1) of the heat recovery pipe 110 at the lower part of the hot water storage tank 103. Also good. In that case, it is desirable that the temperature detector 104 for detecting the temperature of hot water is disposed at a position downstream of the branch point A of the heat recovery pipe 110 (point B in FIG. 1).

Further, in the first embodiment, the controller 13 determines whether or not to perform the drainage treatment of the hot water storage tank 103 and requests the drainer 12 to drain the water. For example, the fuel cell unit 10 includes a controller and drainage (not shown). There is no problem if the internal control unit determines the cost cost and drains it.

(Embodiment 2)
Next, the second embodiment will be described. FIG. 4 is a block diagram showing the configuration of the controller 13 of the fuel cell system according to Embodiment 2 of the present invention. As shown in FIG. 4, the controller 13 includes a drainage amount calculation unit 135 that calculates the amount of drainage by the drainage control unit 133 based on the prediction of the amount of power and hot water supply usage that the fuel cell unit 10 supplies in a predetermined period α. Furthermore, the point which drains the calculated waste_water | drain amount differs from the structure of Embodiment 1. FIG.

In the following, in the processing operation of the controller 13 that controls the drainage of the fuel cell system according to the second embodiment, the controller 13 calculates the amount drained from the hot water storage tank 103 and puts it in the drainer 12 until the drainage is completed. The case where drainage is required will be described with reference to FIGS.

FIG. 5 is a flowchart showing the processing operation of the controller 13 that controls the drainage of the fuel cell system according to Embodiment 2 of the present invention. In the processing operation of the first embodiment (FIG. 3), the amount of drainage is uniquely determined when the temperature of the water supplied from the water supply 106 is constant, whereas in the flow of the second embodiment, the fuel cell system It differs in that it depends on the prediction of the amount of power to be supplied and the amount of hot water used.

In the temperature detector 104 that detects the temperature of the hot water in the hot water storage tank 103, the demand prediction unit 131 has exceeded the first predetermined temperature that is lower than the system stop temperature at which the system needs to be stopped. In the case (YES in step S30 in FIG. 5), the amount of electric power and the amount of hot water supply used by the fuel cell system are predicted for a predetermined period α.

FIG. 6A is a graph showing the demand prediction of the fuel cell system when it is possible to continue the power generation. As shown to Fig.6 (a), the demand prediction part 131 is the state (full condition) in which the temperature of the hot water of the hot water storage tank 103 exceeded the 1st predetermined temperature lower than the system stop temperature which needs to make a system stop. To a predetermined period α (the time from full time t ₀ to time t _{1 in} FIG. 6) is predicted. Here, the predetermined period α is set to a time from when the fuel cell system is stopped until it again enters a power generation state, for example, 2 hours. Here, a power demand of 500 [W] is predicted through a predetermined period α, and a total hot water supply demand of 60 [l] is predicted from time t ₀₁ and a total hot water supply demand of 80 [l] is predicted from time t ₀₂ . . Here, for the prediction of the amount of power and the amount of hot water supply used by the fuel cell system, for example, a prediction that the current power load and the use of hot water supply will continue or a prediction based on past data may be used.

Next, the drainage amount calculation unit 135 calculates the amount of water drained from the hot water storage tank 103 necessary for continuation of power generation based on the prediction of the amount of power supplied by the fuel cell system during the predetermined period α and the amount of hot water used (see FIG. Step S31). As shown in the graph of FIG. _6A, since a hot water supply demand of a total of 60 [l] is predicted from the time t ₀₁ , the drainage amount calculation unit 135 is 500 [W] from the time t ₀ to the time t ₀₁ . Calculate the amount of drainage required to drain excess heat to achieve electricity demand.

Next, the charge calculation unit 132 uses the calculated amount of drainage to perform power generation by draining the hot water storage tank 103 during a predetermined period α, and when it stops without draining during the predetermined period α. In this case, the sum of water charges, electricity charges, and gas charges is calculated (step S32 in FIG. 5).

FIG. 6B is a graph illustrating an example of a user's charge burden when power generation is continued in the predetermined period α. As shown in FIG. 6 (b), water rate A due to waste water amount calculated from the time t ₀ to time t ₀₁ becomes the burden of the user. Further, since the power generation of the fuel cell system is continued during the predetermined period α, the gas charge B used for power generation is also included in the user's burden. The charge calculation unit 132 adds the water charge A and the gas charge B, and calculates the sum of the charges when power generation is continued.

FIG. 6C is a graph showing an example of the user's charge burden when power generation is stopped during the predetermined period α. As shown in FIG. 6 (c), since the power generation of the fuel cell system is stopped in the predetermined period α, only the electricity bill for covering the power generation by the fuel cell system becomes the burden on the user. In the same graph shows a case in which electricity rates are at night discount at time t _03. Thus, since drainage and power generation are not performed during the predetermined period α, neither the water charge A associated with drainage nor the fuel gas charge of the fuel cell associated with power generation is generated. The charge calculation unit 132 calculates the electricity charge C as the sum of charges when power generation is stopped.

Thereafter, if the drainage control unit 133 determines that it is cheaper to continue the power generation by draining the hot water storage tank 103 based on the calculation result (YES in step S33 in FIG. 5), a signal requesting drainage to the drainer 12 is sent. Transmit (step S34 in FIG. 5). In the example of FIG. 6B and FIG. 6C, the drainage control unit 133 uses the user's charge (water charge A and gas charge B) when power generation is continued and the user's charge when power generation is stopped. When (electricity charge C) is compared, it is determined that the user's charge is lower when power generation is continued, and therefore a drainage request signal is transmitted.

Then, when the drainage of the calculated drainage amount is completed (branch Y in step S35 in FIG. 5), the drainage control unit 133 stops the signal requesting drainage that has been transmitted to the drainer 12 (step in FIG. 5). S36).

The graph of FIG. 6 shows an example when the power generation continuation is advantageous, but the graph of FIG. 7 shows an example of the demand prediction of the fuel cell system and the user burden when the power generation stop is advantageous. . As shown in FIG. 7 (a), the demand prediction unit 131 again has a state where the temperature of the hot water in the hot water storage tank 103 exceeds a first predetermined temperature lower than the system stop temperature at which the system needs to be stopped (full state). The demand in the predetermined period α (2 hours) is predicted from the (livestock state) (step S30 in FIG. 5). Here, a power demand of 500 [W] is predicted through the predetermined period α, and a hot water supply demand is not predicted.

Since the demand for hot water supply is not predicted in the predetermined period α, the drainage amount calculation unit 135 calculates the amount of drainage necessary for draining excess heat to realize only the power demand of 500 [W] in the predetermined period α. . Here, when the amount of drainage is calculated (step S31 in FIG. 5), it is predicted that the electric energy will continue for 500 [W] for a predetermined period α (2 hours) and there is no hot water supply operation. ] Is determined as A [l] based on the exhaust heat recovery efficiency of the heat exchanger 101, and the amount of drainage is 2 × A based on the value. And calculate. In addition, the calculation method of the amount of drainage in this Embodiment 1 is not limited to Embodiment 1. FIG.

FIG. 7B is a graph showing an example of a user's charge burden when power generation is continued in a predetermined period α. As shown in FIG. 7 (b), the water charge A associated with the amount of drainage calculated in the predetermined period α is the user's burden. Further, since the power generation of the fuel cell system is continued during the predetermined period α, the gas charge B used for power generation is also included in the user's burden. The charge calculation unit 132 adds the water charge A and the gas charge B, and calculates the sum of the charges when power generation is continued.

FIG. 7C is a graph showing an example of a user's charge burden when power generation is stopped during a predetermined period α. As shown in FIG. 7C, since the power generation of the fuel cell system is stopped in the predetermined period α, the electricity charge for covering the power generation by the fuel cell system becomes a burden on the user. Thus, since drainage and power generation are not performed during the predetermined period α, neither the water charge A associated with the drainage nor the fuel gas charge of the fuel cell associated with the power generation occurs. The charge calculation unit 132 calculates the electricity charge C as the sum of charges when power generation is stopped.

In the example of FIG. 7B and FIG. 7C, the drainage control unit 133 uses the user's charge (water charge A and gas charge B) when power generation is continued and the user's charge when power generation is stopped. When (electricity charge) is compared, it is determined that the user's charge is higher when power generation is continued, and therefore a signal for stopping power generation is transmitted to the fuel cell unit 10 (NO in step S33 of FIG. 5).

According to the second embodiment, similar to the processing operation of the first embodiment, in the fuel cell system that is generating power, the hot water storage tank so that the sum of water charges, electricity charges, and gas charges used by the system user is reduced. 103 can be drained and power generation can be continued, or the system can be stopped without draining, so the economic burden on the system user can be reduced. Moreover, since the economic loss due to the drainage of the hot water storage tank can be reduced, it is not necessary to provide a water storage device, which is useful for increasing the installation opportunity in the market.

In the first embodiment, since the amount of wastewater is calculated only by temperature, there is an advantage that it is easy to calculate the amount of wastewater. On the other hand, since the amount of wastewater is uniquely determined, the processing when the demand fluctuates is not considered. The second embodiment solves this problem.

FIG. 8 is a graph showing an example of the user burden when the demand fluctuation of the fuel cell system occurs when it is predicted that the power generation continuation is obtained in the second embodiment.

As shown in FIG. 8 (a), the demand prediction unit 131 again has a state in which the temperature of the hot water in the hot water storage tank 103 exceeds a first predetermined temperature lower than the system stop temperature at which the system needs to be stopped (full state). The demand in the predetermined period α (2 hours) is predicted from the (livestock state) (step S30 in FIG. 5). Here, a power demand of 500 [W] is predicted over a predetermined period α, and a total hot water supply demand of 60 [l] is predicted from time t ₀₁ .

Wastewater calculating unit 135, as shown in the graph of FIG. 8 (a), since the hot-water demand of the total 60 [l] from the time _{t 01} is predicted, 500 from time _{t 0} to time _{t 01} [W] In order to drain an excessive amount of heat to realize the power demand, a necessary amount of drainage is calculated (step S31 in FIG. 5).

The charge calculation unit 132 calculates the sum of the charges using the calculated amount of drainage (step 32 in FIG. 5), and the drainage control unit 133 determines that the user burden is enough to continue the power generation. The drainage amount is reduced (step 33 in FIG. 5).

However, as shown in FIG. 8 (a), (two-dot chain line) Actual hot water demand does not occur until time t _02. In this case, the drainage control unit 133 sums the charges when the power generation shown in FIG. 8B is continued (water charge A + gas charge B) and the charges when the power generation shown in FIG. 8C is stopped. Continue draining until (Electricity Charge C) is equal. That is, the drainage control unit 133 continues draining to the breakeven point so that the user of the fuel cell system does not lose.

As described above, according to the second embodiment, the temperature of the hot water in the hot water storage tank can be efficiently lowered to a temperature at which the system can be continued based on the prediction of the amount of supplied power and the amount of hot water used. It becomes the minimum amount of drainage and can save water charges more.

(Embodiment 3)
Next, the third embodiment will be described. In the third embodiment, when the electric power generated by the fuel cell unit 10 can be sold, the controller 13 is different from the first and second embodiments in that the controller 13 performs drainage in consideration of the electric charge that can be sold.

In the third embodiment, when the controller 13 requests drainage from the drainer 12 until the temperature of the temperature detector 104 falls to a predetermined temperature (hereinafter, processing operation of the first embodiment), the controller 13 In the case where the amount drained from the hot water storage tank 103 is calculated and drainage is requested to the drainage device 12 until drainage is completed (hereinafter, processing operation of the second embodiment), the power generated by the fuel cell unit 10 can be sold. In this case, the controller 13 performs drainage in consideration of the electricity charge that can be sold.

Hereinafter, the processing operation of the controller 13 when the electric power generated by the fuel cell unit 10 can be sold will be described with reference to FIGS. 1, 2, and 9.

FIG. 9 is a flowchart showing the processing operation when the controller 13 according to Embodiment 3 of the present invention considers power sale. Here, the flow diagram of FIG. 9 describes, as an example, the case of adding to the processing operation of the first embodiment, but the same applies to the case of adding to the processing operation of the second embodiment.

In the temperature detector 104 that detects the temperature of the hot water in the hot water storage tank 103, the demand prediction unit 131 has exceeded the first predetermined temperature that is lower than the system stop temperature at which the system needs to be stopped. In the case (YES in step S40 in FIG. 9), the amount of electric power and the amount of hot water supply used by the fuel cell system are predicted for a predetermined period α.

Next, based on the prediction of the amount of power supplied by the fuel cell system and the amount of hot water used, the charge calculation unit 132 has a second temperature at which the temperature of the temperature detector 104 is lower than the first predetermined temperature and the system operation can be continued. When the power generation is continued by draining the hot water storage tank 103 so that the temperature drops to a predetermined temperature, and when the system is shut down without draining, the sum of water charges, electricity charges, and gas charges in each case is calculated (Fig. 9 step S41). Furthermore, the fee calculation unit 132 calculates the amount of money obtained by selling the power generated by the fuel cell unit 10 (step S42 in FIG. 9).

In the drainage control unit 133, the value obtained by subtracting the amount calculated in step S42 of FIG. 9 from the sum of the water rate, the electricity rate, and the gas rate to be used when draining is lower than when the drainage is not performed. In the case (YES in step S43 in FIG. 9), drainage is performed. As a result, the hot water storage tank 103 is drained so that the sum of the water bill to be used, the electricity bill considering the sold electricity bill, and the gas bill is reduced, and the power generation is continued, or the system can be stopped without draining. Therefore, it is useful for reducing the economic burden on the system user in an area where the power generated by the fuel cell unit 10 can be sold. The amount of money obtained by selling the power generated by the fuel cell unit 10 is the power selling price per unit power input by the user of the fuel cell system or the power selling price per unit power acquired from the net or the like. You may calculate based on.

(Embodiment 4)
Next, the fourth embodiment will be described. In the fourth embodiment, when the subsidy is obtained by using the electric power generated by the fuel cell unit 10, the controller 13 performs the drainage in consideration of the subsidy and the first embodiment and the first embodiment. Different from 2.

Hereinafter, the processing operation of the controller 13 when subsidies are obtained by using the power generated by the fuel cell unit 10 will be described with reference to FIGS. 1, 2, and 10.

FIG. 10 is a flowchart showing a processing operation in the case of considering subsidies in the controller 13 according to the fourth embodiment of the present invention. Here, the flow diagram of FIG. 10 describes, as an example, the case of adding to the processing operation of the first embodiment, but the same applies to the case of adding to the processing operation of the second embodiment.

In the temperature detector 104 that detects the temperature of the hot water in the hot water storage tank 103, the demand prediction unit 131 has exceeded the first predetermined temperature that is lower than the system stop temperature at which the system needs to be stopped. In the case (YES in step S50 in FIG. 10), the amount of electric power and the amount of hot water supply used by the fuel cell system are predicted for a predetermined period α.

Next, based on the prediction of the amount of power supplied by the fuel cell system and the amount of hot water used, the charge calculation unit 132 has a second temperature at which the temperature of the temperature detector 104 is lower than the first predetermined temperature and the system operation can be continued. When the power generation is continued by draining the hot water storage tank 103 so that the temperature drops to a predetermined temperature, and when the system is shut down without draining, the sum of water charges, electricity charges, and gas charges in each case is calculated (Fig. 10 step S51). Furthermore, the fee calculation unit 132 calculates a subsidy obtained when the user of the fuel cell system uses the electric power generated by the fuel cell unit 10 (step S52 in FIG. 10).

The drainage control unit 133 deducts the subsidy calculated in step S52 of FIG. 10 from the sum of water charges, electricity charges, and gas charges to be used when draining, and is cheaper than when drainage is not performed. If this is the case (YES in step S53 in FIG. 10), drainage is performed. As a result, the hot water storage tank 103 is drained so that the sum of water charges to be used, subsidies for using generated power, and gas charges is reduced, and the power generation is continued or the system is stopped without draining. Therefore, it is useful for reducing the economic burden on system users in areas where subsidies can be obtained by using the power generated by the power generation unit. Further, the subsidy obtained by using the power generated by the fuel cell unit 10 may be calculated based on a fee input by a user of the fuel cell system or a fee acquired from the net or the like.

(Embodiment 5)
Next, the fifth embodiment will be described. The fifth embodiment is different from the first and second embodiments in that drainage is performed in consideration of the amount of heat loss associated with drainage of hot water stored in the hot water storage tank 103.

Hereinafter, the processing operation in the case where the controller 13 considers the amount of heat loss associated with the drainage of hot water stored in the hot water storage tank 103 will be described with reference to FIGS. 1, 2, and 11.

FIG. 11 is a flowchart showing the processing operation when the controller 13 according to the fifth embodiment of the present invention considers the amount of heat loss. Here, the flow diagram of FIG. 11 describes, as an example, the case of adding to the processing operation of the first embodiment, but the same applies to the case of adding to the processing operation of the second embodiment.

In the temperature detector 104 that detects the temperature of the hot water in the hot water storage tank 103, the demand prediction unit 131 has exceeded the first predetermined temperature that is lower than the system stop temperature at which the system needs to be stopped. In the case (YES in step S60 in FIG. 11), the amount of electric power and the amount of hot water supply used by the fuel cell system are predicted for a predetermined period α.

Next, based on the prediction of the amount of power supplied by the fuel cell system and the amount of hot water used, the charge calculation unit 132 has a second temperature at which the temperature of the temperature detector 104 is lower than the first predetermined temperature and the system operation can be continued. When the power generation is continued by draining the hot water storage tank 103 so that the temperature drops to a predetermined temperature, and when the system is shut down without draining, the sum of water charges, electricity charges, and gas charges in each case is calculated (Fig. 11 step S61). Furthermore, the charge calculation unit 132 calculates the amount of heat loss due to the drainage of hot water stored in the hot water storage tank 103 by heat exchange with the exhaust gas of the fuel cell unit 10 (step S62 in FIG. 11).

The drainage control unit 133 adds the loss amount calculated in step S62 in FIG. 11 to the sum of the water charges, electricity charges, and gas charges to be used when draining, and is cheaper than when drainage is not performed. If this is the case (YES in step S63 in FIG. 11), drainage is performed. As a result, drainage of the hot water storage tank 103 is continued and power generation is continued so that the sum of the gas charge considering the gas charge used for the heat rate of the hot water storage tank 103 that is wasted due to the water charge, electricity charge, and drainage used is reduced. Alternatively, the system can be stopped without draining, which is useful for reducing the economic burden on the system user and improving the accuracy when calculating the economic burden.

In addition, for example, the fuel cell system further includes a temperature sensor (not shown) in the vicinity of the drain pipe 107 and the water supply pipe 109 to supply water with the temperature of hot water detected by the temperature sensor. The amount of hot water in the hot water storage tank 103 may be calculated based on the difference from the temperature of the water, and the charge of the gas used as the amount of heat may be calculated based on the exhaust heat recovery efficiency of the heat exchanger 101. Alternatively, a flow meter (not shown) that can measure the flow rate of the gas passing through the heat exchanger 101 is provided, and the gas charge used as the amount of heat for the hot water in the hot water storage tank 103 is calculated from the total amount of the gas flow rate used in the fuel cell unit 10. It doesn't matter.

Moreover, when calculating the gas charge used for the heat quantity from the total amount of the gas flow rate, for example, the exhaust gas from the fuel cell 100 is 70% of the gas used in the fuel cell unit 10, and the exhaust heat of the heat exchanger 101 is calculated. When the recovery efficiency is 90%, the gas charge used for the heat quantity may be gas charge used by the fuel cell unit 10 × 0.7 × 0.9. In addition, when the hot water storage tank 103 is provided with a heat source, the used gas fee may be calculated excluding the amount of heat generated by the operation of the heat source.

In the case of the processing operation of the second embodiment shown in FIG. 5, when considering the amount of heat loss due to the drainage of hot water stored in the hot water storage tank 103, the electricity charge is significantly higher than the water charge or gas charge. Even if the amount of heat stored in the hot water storage tank 103 is taken into account, if the total amount of water, electricity, and gas used by the person who drains all of the hot water in the hot water storage tank 103 becomes cheaper, empty the tank once. It doesn't matter.

(Embodiment 6)
Next, the sixth embodiment will be described. In the sixth embodiment, the fuel cell system is further provided with a power storage unit (not shown) that stores the generated power of the fuel cell unit 10 and drains in consideration of a reduction in the electricity bill obtained by power storage. Different from Embodiment 1 and Embodiment 2.

Hereinafter, the processing operation of the controller 13 when the electricity bill is reduced by storing the electric power generated by the fuel cell unit 10 in the power storage unit will be described with reference to FIGS. 1, 2, and 12.

FIG. 12 is a flowchart showing a processing operation when the controller 13 according to the sixth embodiment of the present invention considers reduction of the electricity bill due to power storage. Here, the flow diagram of FIG. 12 describes, as an example, the case where the processing operation is added to the processing operation of the first embodiment, but the same applies to the case where the processing operation is added to the processing operation of the second embodiment.

In the temperature detector 104 that detects the temperature of the hot water in the hot water storage tank 103, the demand prediction unit 131 has exceeded the first predetermined temperature that is lower than the system stop temperature at which the system needs to be stopped. In the case (YES in step S70 in FIG. 12), the amount of electric power and the amount of hot water supply used by the fuel cell system are predicted for a predetermined period α.

Next, based on the prediction of the amount of power supplied by the fuel cell system and the amount of hot water used, the charge calculation unit 132 has a second temperature at which the temperature of the temperature detector 104 is lower than the first predetermined temperature and the system operation can be continued. When the power generation is continued by draining the hot water storage tank 103 so that the temperature drops to a predetermined temperature, and when the system is shut down without draining, the sum of water charges, electricity charges, and gas charges in each case is calculated (Fig. 12 step S71). Furthermore, the charge calculation unit 132 acquires the power that can be stored in the power storage unit (step S72 in FIG. 12), and calculates the reduction amount of the electricity charge obtained by power storage based on the acquired power that can be stored (FIG. 12). Step S73).

The drainage control unit 133 did not drain the amount calculated by subtracting the amount of electricity bill calculated in step S73 of FIG. 12 from the sum of the water bill, electricity bill, and gas bill to be used when draining. If it is cheaper than usual (branch Y in step S74 in FIG. 12), drainage is performed. As a result, the hot water storage tank 103 is drained so that the sum of the water charge to be used, the electricity charge considering the use of the power charged in the power storage unit, and the gas charge is reduced, and the power generation is continued or the system is stopped without draining. Therefore, it is useful for reducing the economic burden on the system user in the case where the fuel cell system includes an electricity storage unit.

(Embodiment 7)
Next, the seventh embodiment will be described. The seventh embodiment is different from the processing operation of the second embodiment in that the amount drained by the drainer 12 is calculated and the amount is controlled to be divided and drained.

Hereinafter, the processing operation in the case where the controller 13 calculates the amount drained by the drainer 12 and performs control to divide and drain the amount will be described with reference to FIGS. 1, 4, and 13. .

FIG. 13 is a flowchart showing a processing operation when the controller 13 according to Embodiment 2 of the present invention calculates the amount drained by the drainer 12 and controls to divide and drain the amount. .

In the temperature detector 104 that detects the temperature of hot water in the hot water storage tank 103, the demand prediction unit 131 shown in FIG. 4 has a first predetermined temperature lower than the system stop temperature at which the hot water storage tank 103 needs to be stopped. When the temperature is exceeded (step S80 in FIG. 13), the amount of electric power and the amount of hot water supply used by the fuel cell system are predicted for a predetermined period α.

Next, the drainage amount calculation unit 135 calculates the amount of drainage by the drainage device 12 based on the power load supplied by the fuel cell system and the prediction of hot water supply use (step S81 in FIG. 13).

Next, the charge calculation unit 132 uses the calculated amount of drainage to perform power generation by draining the hot water storage tank 103 during a predetermined period α, and when it stops without draining during the predetermined period α. In this case, the sum of the water charge, the electricity charge, and the gas charge is calculated (step S82 in FIG. 13).

Thereafter, if the drainage control unit 133 determines that it is cheaper to drain the hot water storage tank 103 and continue power generation based on the calculation result (YES in step S83 in FIG. 13), a signal requesting drainage to the drainer 12 is sent. Transmit (step S84 in FIG. 13).

When the drainage control unit 133 completes a certain amount of drainage obtained by dividing the drainage amount calculated in step S81 in FIG. 13 (branch Y in step S85 in FIG. 13), the drainage amount calculated in step S81 in FIG. It is confirmed whether it has been completed (step S86 in FIG. 13).

If the drainage amount calculated in step S81 in FIG. 13 is not completed (branch N in step S86 in FIG. 13), the drainage control unit 133 checks whether drainage needs to be continued (step S87 in FIG. 13). ). At this time, for example, when there is actually a hot water supply demand, it may be determined that there is no need to continue draining.

If the drainage control unit 133 determines in step 87 that drainage needs to be continued (YES in step S87 in FIG. 13), the drainage control unit 133 continues to transmit a signal requesting drainage to the drainer 12 (in FIG. 13). Step S84), draining is continued.

On the other hand, the drainage control unit 133 checks whether the drainage of the drainage amount calculated in step S81 of FIG. 13 is completed (step S86 of FIG. 13), and when the drainage of the drainage amount calculated in step S81 of FIG. 13, YES in step S86), and confirms whether drainage is to be continued (step S87 in FIG. 13). If drainage is not required (NO in step S87 in FIG. 13), the drainage control unit 133 performs drainage. The signal for requesting drainage to the vessel 12 is stopped (step S88 in FIG. 13), and the drainage process is terminated.

Thereby, the prediction of the amount of drainage calculated by the controller 13 deviates, and the power load to which the fuel cell unit 10 supplies electric power is reduced more than expected, so that it is not necessary to continue the power generation, or the hot water storage tank more than expected. When it is no longer necessary to continue drainage by using hot water from 103, it is possible to reduce wasteful wastewater due to mispredictions by interrupting drainage, which is useful for reducing the economic burden on system users. is there. In the flow chart of FIG. 13 in the seventh embodiment, the hot water drainage of the hot water storage tank 103 is divided and drained at regular intervals, but may be drained at regular intervals, for example.

(Embodiment 8)
Next, the power supply system in Embodiment 8 of this invention is demonstrated using drawing.

The block diagram of the fuel cell system in the eighth embodiment is FIG. 1 similar to that in the first embodiment of the present invention, and a description thereof will be omitted.

FIG. 14 is a flowchart showing the processing operation of the controller 13 for controlling the drainage of the fuel cell system in the eighth embodiment. FIG. 14 and the flow charts (FIGS. 3 and 9 to 13) showing the processing operation of the controller 13 for controlling the drainage of the fuel cell system shown in the first embodiment, the fuel cell system is stopped. It differs greatly in whether it is generating electricity.

First, in the processing operation of the controller 13 that controls the drainage of the fuel cell system that is stopped in the eighth embodiment, the controller 13 requests the drainer 12 to drain until the temperature of the temperature detector 104 falls to a predetermined temperature. The processing operation in this case will be described with reference to FIGS.

When the temperature detector 104 that detects the temperature of hot water in the hot water storage tank 103 cannot restart the demand prediction unit 131 because the hot water temperature in the hot water storage tank 103 is equal to or higher than the system stop temperature at which the system needs to be stopped (see FIG. 14 in step S90) predicts the amount of power and the amount of hot water used by the fuel cell system during the predetermined period α.

Next, the charge calculation unit 132 can restart the fuel cell system in a predetermined period α based on the prediction of the power load supplied by the fuel cell system and the use of hot water supply, and the temperature of the temperature detector 104 is lower than the system stop temperature. When water is restarted by draining the hot water storage tank 103 so that the temperature drops to a predetermined temperature, and when it is stopped without draining for a predetermined period α, water charges, electricity charges, and gas charges in each case The sum is calculated (step S91 in FIG. 14).

After that, if the drainage control unit 133 determines that it is cheaper to drain and restart the hot water storage tank 103 based on the calculation result (YES in step S92 in FIG. 14), the fuel cell unit 10 resumes power generation. A request signal is transmitted (step S93 in FIG. 14), and a signal requesting drainage is transmitted to the drainage device 12 (step S94 in FIG. 14).

Then, when the temperature of the temperature detector 104 is lowered to a predetermined temperature at which the fuel cell system can be restarted lower than the system stop temperature (YES in step S95 in FIG. 14), the drain controller 133 The signal for requesting drainage that has been transmitted to is stopped (step S96 in FIG. 14). As a result, in the fuel cell system being stopped, the hot water storage tank 103 is drained to restart the power generation so that the sum of water charges, electricity charges, and gas charges to be used is reduced, or power generation is resumed or the stopped state is continued without draining. Therefore, it is useful for reducing the economic burden on the system user.
(Embodiment 9)
Next, the ninth embodiment will be described. In the ninth embodiment, in the processing operation for controlling the drainage of the fuel cell system, the controller 13 calculates the amount drained from the hot water storage tank 103, and the drainage unit 12 is requested to drain until the drainage of the calculated drainage amount is completed. This will be described with reference to FIG. 1, FIG. 4, and FIG.

FIG. 15 is a flowchart showing the processing operation for controlling the drainage of the fuel cell system according to Embodiment 9 of the present invention. In the processing operation of the eighth embodiment (FIG. 14), the amount of drainage is uniquely determined when the temperature of the water supplied from the water supply 106 is constant, whereas in the flow of the ninth embodiment, the fuel cell system Differing in that it depends on the power load supplied by and the prediction of hot water usage.

When the temperature detector 104 that detects the temperature of hot water in the hot water storage tank 103 cannot restart the demand prediction unit 131 because the hot water temperature in the hot water storage tank 103 is equal to or higher than the system stop temperature at which the system needs to be stopped (see FIG. 15 in step S100) predicts the amount of electric power and the amount of hot water used by the fuel cell system during the predetermined period α.

Next, the drainage amount calculation unit 135 calculates the amount of drainage from the hot water storage tank 103 necessary for restarting the fuel cell system based on the power load supplied by the fuel cell system and the prediction of hot water supply usage (step of FIG. 15). S101).

The drainage control unit 133 uses the calculated drainage amount to restart the drainage of the hot water storage tank 103 and when the drainage control unit 133 continues the stopped state without draining, in each case, the water rate, the electricity rate, The sum of gas charges is calculated (step S102 in FIG. 15).

If the drainage control unit 133 subsequently determines that it is cheaper to drain and restart the hot water storage tank 103 based on the calculation result (YES in step S103 in FIG. 15), the drainage control unit 133 requests the fuel cell unit 10 to start up. A signal is transmitted (step S104 in FIG. 15), and a signal requesting drainage is transmitted to the drainage device 12 (step S105 in FIG. 15).

Then, when the drainage of the calculated drainage amount is completed (YES in step S106 in FIG. 15), the drainage control unit 133 stops the signal requesting drainage that has been transmitted to the drainer 12 (step in FIG. 15). S107). Similarly to the flow of the processing operation of the eighth embodiment, this method also generates power by draining the hot water storage tank 103 so that the sum of water charges, electricity charges, and gas charges to be used is reduced in the stopped fuel cell system. Can be resumed, or the stopped state can be continued without draining, which is useful for reducing the economic burden on the system user.
(Embodiment 10)
Next, the tenth embodiment will be described. In the tenth embodiment, in the stopped fuel cell system, as in the second embodiment, the controller 13 calculates the amount drained by the drainage device 12 and controls to divide the amount and drain the water. .

Hereinafter, the processing operation in the case where the controller 13 calculates the amount of drainage by the drainer 12 and controls to divide and drain the amount will be described with reference to FIGS. 1, 4, and 16. To do.

FIG. 16 is a flowchart showing a processing operation when the controller 13 according to the tenth embodiment of the present invention calculates the amount drained by the drainer 12 and controls to divide and drain the amount. .

When the temperature detector 104 that detects the temperature of hot water in the hot water storage tank 103 cannot restart the demand prediction unit 131 because the hot water temperature in the hot water storage tank 103 is equal to or higher than the system stop temperature at which the system needs to be stopped (see FIG. 16 in step S110) predicts the amount of power and the amount of hot water used by the fuel cell system during the predetermined period α.

Next, the drainage amount calculation unit 135 calculates the amount of drainage by the drainer 12 based on the prediction of the power load and hot water supply used by the fuel cell system in the predetermined period α (step S111 in FIG. 16).

Next, when the charge calculation unit 132 is restarted by draining the hot water storage tank 103 in the predetermined period α using the calculated drainage amount, and when the drainage is not performed and the stop state is continued in the predetermined period α. Then, the sum of water charges, electricity charges, and gas charges in each case is calculated (step S112 in FIG. 16).

Thereafter, if the drainage control unit 133 determines that it is cheaper to drain and restart the hot water storage tank 103 based on the calculation result (YES in step S113 in FIG. 16), the drainage control unit 133 requests the fuel cell unit 10 to restart power generation. A signal for requesting drainage is transmitted to the drainage device 12 (step S115 in FIG. 16).

When the drainage control unit 133 completes a certain amount of drainage obtained by dividing the drainage amount calculated in step S111 of FIG. 16 (YES in step S116 of FIG. 16), the drainage of the drainage amount calculated in step S111 of FIG. 16 is completed. 16 (step S117 in FIG. 16), and if drainage of the drainage amount calculated in step S111 in FIG. 16 is not completed (NO in step S117 in FIG. 16), it is confirmed whether drainage needs to be continued ( FIG. 11 step S118). At this time, for example, when there is actually a hot water supply demand, it may be determined that there is no need to continue draining.

When the drainage control unit 133 needs to continue draining (YES in step S118 in FIG. 16), the drainage control unit 133 continues to send a signal requesting drainage to the drainer 12 (step S115 in FIG. 16) and continues draining. .

On the other hand, the drainage control unit 133 checks whether the drainage of the drainage amount calculated in step S111 of FIG. 16 is completed (step S117 of FIG. 16), and the drainage of the drainage amount calculated in step S111 of FIG. 16 (YES in step S117), and confirms whether or not continuation of drainage is necessary (step S118 in FIG. 16). If continuation of drainage is not necessary (NO in step S118 in FIG. 16), the drainage device 12 is drained. The requested signal is stopped (step S119 in FIG. 16), and the drainage process is terminated.

In this method, when the amount of drainage calculated by the drainage amount calculation unit 135 is deviated, the power load supplied by the fuel cell unit 10 is lower than expected, and it is no longer necessary to restart power generation. When it is no longer necessary to continue drainage by using hot water from the hot water storage tank 103, wastewater drainage due to mispredictions can be reduced by interrupting drainage, thus reducing the economic burden on system users Useful for. In the flow chart of FIG. 16 according to the tenth embodiment of the present invention, the hot water drainage of the hot water storage tank 103 is divided and drained at regular intervals, but may be drained at regular intervals, for example. Absent.

In the processing operation of the ninth embodiment and the tenth embodiment, the controller 13 sells the power generated by the fuel cell unit 10 based on the power load supplied by the fuel cell system and the prediction of hot water supply use. Or subsidies obtained by the user of the fuel cell system using the electric power generated by the fuel cell unit 10, or the amount of loss associated with the drainage of the amount of heat stored in the hot water storage tank 103, or storage It is also possible to calculate a reduction amount of the electricity charge obtained by the above and control whether to restart by performing drainage based on the above-mentioned calculation result and the sum of the water charge, electricity charge and gas charge to be used.

(Embodiment 11)
In addition, in each said embodiment, although it was the structure which drains the heat of a hot water storage tank with the drainage device 12 which drains the hot water stored in the hot water storage tank 103, it is not limited to such a structure. . FIG. 17 is a block diagram of the fuel cell system according to Embodiment 11 of the present invention. As shown in FIG. 17, a radiator (radiator) 111 is arranged in the hot water storage tank 103 of the fuel cell system. Specifically, the hot water storage tank 103 is provided with a flow path from the upper part to the lower part of the hot water storage tank 103, and a pump and a radiator 111 (not shown) are provided in the flow path. When the heat is radiated, the controller is controlled by the controller 13 so that the hot water is supplied from the upper part to the lower part of the hot water storage tank 103. Then, the hot water is taken out from the upper part of the hot water storage tank 103 and radiates heat in the radiator 111 to decrease the temperature, and the hot water whose temperature has decreased is returned to the lower part of the hot water storage tank 103. According to the eleventh embodiment configured as described above, since the heat of the hot water storage tank 103 is radiated by the radiator, there is no charge for water supply as in the case where the hot water is drained by the drain. Thereby, the economic burden on the system user can be further reduced.

(Modification)
As a modification of the eleventh embodiment, instead of the radiator 111 described above, a flow path from the start end C of the heat recovery pipe 110 of FIG. 17 to the downstream portion D is separately provided, and a radiator is further provided in the flow path. By providing, this heat radiator may be operated under the control of the controller 13 during heat radiation.

In each of the above-described embodiments (including modifications), the predetermined period α is set to a time from when the fuel cell system is stopped until the power generation state is restored, for example, 2 hours. However, the present invention is not limited to this, and may be determined based on an operation plan in the installation area of the fuel cell system.

As described above, when the fuel cell system according to the present invention drains hot water from a hot water storage tank to generate power from the fuel cell system, the water charge, electricity charge, gas used when the hot water is drained from the hot water storage tank. By draining the fuel cell only when the sum of the charges is lower than the sum of the water, electricity, and gas charges used when stopping the fuel cell system without draining hot water from the hot water storage tank, Even when the system drains hot water from the hot water storage tank, the impact on the economy can be taken into account, so it can be applied to the use of a power supply system including a power generation device such as a fuel cell system and a hot water storage tank. it can.

10 Fuel Cell Unit 11 Hot Water Storage Unit 12 Drainage Unit (Exhaust Heat Unit)
13 Controller 100 Fuel cell 101 Heat exchanger 103 Hot water storage tank 104 Temperature detector (heat storage amount detection unit)
110 Heat recovery piping 111 Radiator (heat exhaust part)
131 Demand prediction unit 132 Charge calculation unit 133 Drainage control unit 134 Storage unit 135 Drainage amount calculation unit

Claims

A fuel cell unit that is supplied with fuel gas to generate heat and generates electric power and heat;
A hot water storage unit comprising a hot water storage tank for storing the heat supplied from the fuel cell unit as hot water;
An exhaust heat section for exhausting heat stored in the hot water storage tank;
A heat storage amount detection unit for detecting a heat storage amount of the hot water storage tank;
A controller that stops power generation of the fuel cell unit when the amount of heat stored in the hot water storage tank reaches an upper limit, and
When the control unit detects that the heat storage amount detection unit is greater than or equal to a first predetermined heat storage amount, based on the prediction of the amount of power supplied by the fuel cell unit and the amount of heat used in the hot water storage tank, A fuel cell system that calculates usage charges for water, electricity, and gas of a system user, and controls whether or not to exhaust heat by the exhaust heat unit based on the calculated usage charges.
The heat storage amount detection unit detects the temperature of hot water in the hot water storage tank,
The controller is
A predicting unit that predicts the amount of power and hot water usage used by the fuel cell unit in a predetermined period when the heat storage amount detection unit detects that the temperature is equal to or higher than a first predetermined temperature;
Based on the prediction in the predetermined period, the sum of usage charges of water, electricity, and gas when the exhaust heat is exhausted by the exhaust heat unit in the predetermined period is calculated, and the exhaust heat is calculated in the predetermined period. A usage fee calculation unit that calculates the sum of usage fees for water, electricity, and gas when not performed,
The usage fee when the exhaust heat is performed is compared with the usage fee when the exhaust heat is not performed, and the usage fee when the exhaust heat is performed is more than the usage fee when the exhaust heat is not performed. The fuel cell system according to claim 1, further comprising an exhaust heat control unit that performs exhaust heat when the cost is reduced.
3. The fuel cell system according to claim 2, wherein the control unit controls the exhaust heat so that the temperature detected by the heat storage amount detection unit is equal to or lower than a second predetermined temperature lower than the first predetermined temperature.
The control unit calculates the amount of heat exhausted by the exhaust heat unit based on the prediction of the amount of electric power and the amount of hot water used that the fuel cell unit supplies in the predetermined period, and exhausts the calculated amount of exhaust heat. The fuel cell system according to claim 2, wherein the fuel cell system is controlled.
The controller is
The fuel cell system according to claim 4, wherein the calculated exhaust heat amount is divided and exhausted.
The controller is
The value obtained by subtracting the amount obtained by selling the power generated by the fuel cell unit from the sum of the usage fees for water, electricity, and gas when exhaust heat is used is cheaper than when exhaust heat is not used If so, the fuel cell system according to claim 2, wherein exhaust heat is exhausted.
The controller is
When the amount obtained by subtracting subsidies obtained by using the power generated by the fuel cell unit from the sum of the usage fees for water, electricity, and gas when exhaust heat is used does not exhaust heat The fuel cell system according to claim 2, wherein exhaust heat is discharged when the price is lower.
The controller is
The total amount of water, electricity, and gas usage charges when exhaust heat is used plus the amount of heat loss of the hot water storage tank that is wasted due to exhaust heat is cheaper than when exhaust heat is not used If so, the fuel cell system according to claim 2, wherein exhaust heat is exhausted.
A power storage unit for storing the power generated by the fuel cell unit;
The control unit further includes:
The amount obtained by subtracting the amount of electricity usage charges obtained by storing electricity in the electricity storage unit from the sum of usage charges for water, electricity, and gas when exhaust heat is used is greater than when exhaust heat is not used. The fuel cell system according to claim 2, wherein when it becomes cheap, exhaust heat is performed.
The controller is
The fuel cell system according to any one of claims 1 to 9, wherein control is performed so as to resume power generation while the fuel cell unit is stopped, and control is performed so that heat is exhausted by the exhaust heat unit.