JP2005353292A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of restraining lowering of operation efficiency by avoiding generation of warning from a microcomputer meter without invalidating a protection function of the microcomputer meter. <P>SOLUTION: The fuel cell system comprises a fuel cell unit 3 composed of a reforming device 31 generating hydrogen-rich fuel gas h by reforming commercial gas G passing through the microcomputer meter 2, and a fuel cell unit 32 generating electric power to be supplied to a load side by electrochemical reaction of the fuel gas h; a power consumption measuring means 39 measuring the electric power consumed at the load side; and a control device 9 keeping the fuel cell unit 3 in a stopped state for a prescribed second period lasting for a prescribed first period from the start of the operation of the fuel cell unit 3, depending on a schedule of the power consumption measured by the power consumption measuring means 39. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell system, and more particularly to a fuel cell system including a fuel cell that reforms and introduces commercial gas that has passed through a meter that issues an alarm when gas continues to flow for a predetermined time.

  A fuel cell system that is a power generation system equipped with a fuel cell that can significantly reduce emissions of harmful gases such as carbon dioxide and nitrogen oxides, which cause global warming, in recent years, with increasing interest in environmental conservation. Is attracting attention. In general, a fuel cell system reforms a raw material fuel in a reformer to generate a fuel gas rich in hydrogen, and generates electric power by an electrochemical reaction between the generated fuel gas and an oxidant gas containing oxygen. System. As the raw material fuel, various raw material fuels such as city gas, LPG, digestion gas, methanol, GTL (Gas to Liquid) and kerosene can be used. In particular, a fuel cell system is installed at home as a distributed power source. Sometimes, commercial gas such as city gas is used from the viewpoint of availability.

  By the way, when receiving supply of commercial gas, from the viewpoint of safety, there is a case where the supply of gas is received through a meter that issues an alarm or automatically shuts off the gas flow when the gas continues to flow for a predetermined time. This is particularly noticeable when supplying commercial gas at home. A meter having such a protection function is generally called a microcomputer meter. For example, the microcomputer meter can be used for a certain period of time, such as when the gas flows unnaturally in large quantities, such as when the rubber tube is removed, or when the gas usage time is longer than necessary, such as leaving the bath. The gas flow is automatically shut off when a gas of the flow rate of flows, and furthermore, there is a crack in the rubber tube, the gas leaks, and a minute amount of gas continues to flow for a predetermined time (for example, 30 days or more). It is a meter that has a function to issue an alarm when it is not.

  When using commercial gas as a raw material fuel for fuel cells, the gas that has passed through the microcomputer meter may be introduced into the reformer. In general, the gas is supplied via the microcomputer meter at home. It is.

  However, when there is a constant power load constantly, if commercial gas is introduced into the reformer in accordance with the operation of the fuel cell in order to always operate the fuel cell, the gas will be consumed for a predetermined time (for example, 30 days or more). When it continues to flow, even if it is in normal operation, the microcomputer meter may mistakenly recognize that there is a gas leak and issue an alarm. When an alarm is issued, there is annoyance that the user must stop the alarm, and in order to stop the alarm, the microcomputer meter does not detect a pulse for a predetermined time (for example, 3 minutes or more), that is, there is no gas flow. Must be in a state. If the flow of gas introduced into the reformer to stop the alarm is interrupted, the production of fuel gas is stopped, and the fuel cell from which the supply of fuel gas is cut off is also stopped. Once the operation of the fuel cell is stopped, it takes time to return to the steady operation state. If this is performed during a time period when the power load is large, a large amount of power must be purchased from the outside, and the merit of introducing the fuel cell system cannot be fully utilized, that is, the operation efficiency is lowered. On the other hand, it is difficult to disable the protection function of the microcomputer meter from the viewpoint of safety.

  In view of the above-described problems, the present invention provides a fuel cell system capable of avoiding an alarm from being generated by the microcomputer meter and suppressing a decrease in operation efficiency of the fuel cell system without invalidating the protection function of the microcomputer meter. The purpose is to provide.

  In order to achieve the above object, the fuel cell system according to claim 1 introduces a commercial gas G that has passed through a meter 2 that issues an alarm when gas continues to flow for a predetermined time, for example, as shown in FIG. A reformer 31 that reforms the commercial gas G to produce a hydrogen-rich fuel gas h, and a fuel that generates heat by introducing the fuel gas h and supplying power to the load side by an electrochemical reaction A fuel cell unit 3 having a battery 32; a power consumption measuring means 39 for measuring the power consumption used on the load side; and a control device 9 for controlling the start and stop of the fuel cell unit 3 and measuring the power consumption. Based on the schedule of power consumption measured by the means 39, the fuel cell unit 3 is stopped for a second predetermined time after starting the operation of the fuel cell unit 3 until the first predetermined time elapses. Condition And a control unit 9 for holding the.

  If comprised in this way, based on the schedule of the power consumption measured by the power consumption measuring means, after starting the operation of the fuel cell and before the first predetermined time elapses, the fuel cell is set to the second predetermined time. Since the fuel cell system is kept stopped for a period of time, a fuel cell system that prevents the meter from issuing an alarm can be constructed.

  The “commercial gas” refers to a gas that is supplied from outside by paying consideration such as city gas and propane gas. The “load side” refers to a portion that consumes heat such as electricity or hot water, and the “schedule” refers to a time period during which the load side consumes electricity or heat during the day. In addition, the “first predetermined time” typically indicates that the meter issues an alarm when a predetermined flow rate of gas flows for a predetermined time or more, such as when a gas leaks due to a crack in a rubber tube. This is the time required (for example, 30 days). Further, the “second predetermined time” is typically a time (for example, 60 minutes) necessary for interrupting the measurement of the first predetermined time.

  In addition, in the fuel cell system according to claim 2, for example, as shown in FIG. 1, in the fuel cell system according to claim 1, the control device 9 has a time zone in which the power consumption read from the schedule is minimum. Alternatively, the fuel cell unit 3 is held in a stopped state when the power consumption measured by the power consumption measuring means 39 is equal to or lower than a predetermined power in a time zone where the fuel cell unit 3 is below the minimum output.

  With this configuration, the power consumption read from the schedule is a minimum time zone or a time zone where the power consumption is less than the minimum output of the fuel cell unit, and the power consumption measured by the power consumption measuring means is a predetermined power. Since the fuel cell unit is held in the stopped state at the following times, the operation of the fuel cell is stopped when the power load is the minimum or the minimum output of the fuel cell unit and the flow of gas passing through the meter is set to the second predetermined value. As a result of shutting down for a period of time and avoiding the alarm of the meter being issued when the power load is large, it is possible to avoid the stop of the fuel cell operation and minimize the decrease in operational efficiency. It becomes a fuel cell system. The “predetermined power” is typically power corresponding to the minimum value of power consumption read from the schedule or the minimum output of the fuel cell unit, and includes a value multiplied by a margin coefficient.

  Further, as shown in FIG. 1, for example, the fuel cell system according to claim 3 stores heat generated in the fuel cell 32 using hot water as a medium in the fuel cell system according to claim 1 or 2. Hot water storage unit 4; hot water flow rate measuring means 49A and 49B for measuring the flow rate of hot water derived from the hot water storage unit 4 toward the load side; and based on the schedule of the flow rate of hot water measured by the hot water flow rate measuring means 49A and 49B And a control device 9 that holds the fuel cell unit 3 in a stopped state for a second predetermined time after the operation of the fuel cell unit 3 is started until the first predetermined time elapses.

  If comprised in this way, based on the schedule of the flow rate of the warm water measured by the warm water flow rate measuring means, the fuel cell is placed in the second period after the start of the fuel cell until the first predetermined time elapses. Since the fuel cell system is maintained in a stopped state for a predetermined time, it is possible to construct a fuel cell system that prevents the meter from issuing an alarm and further suppresses a decrease in operation efficiency.

  Further, in the fuel cell system according to claim 4, for example, as shown in FIG. 1, in the fuel cell system according to claim 3, the control device 9 is configured such that the amount of heat used on the load side read from the schedule is stored in hot water. Hold fuel cell unit 3 in a stopped state when in unit 4

  With this configuration, since the fuel cell unit is held in a stopped state when the amount of heat used on the load side read from the schedule is in the hot water storage unit, the heat stored in the amount of heat used on the load side is stored in the exhaust heat of the fuel cell. Thus, it is possible to construct a fuel cell system that prevents the meter from issuing an alarm and suppresses a decrease in operational efficiency. Note that “when the amount of heat used on the load side read from the schedule is in the hot water storage unit” typically means the amount of heat that can be used effectively by the hot water storage unit when the fuel cell unit is stopped. Is more than the amount of heat expected to be used while the fuel cell unit is stopped, or when the fuel cell unit is stopped, the amount of heat available to the hot water storage unit and the operation of the fuel cell unit resumes. This is when the total amount of heat with the amount of heat that is expected to be stored after the start is greater than the amount of heat that is expected to be used after the fuel cell unit is stopped.

  Further, in the fuel cell system according to claim 5, for example, as shown in FIG. 1, in the fuel cell system according to claim 3 or 4, the control device 9 has a minimum flow rate of hot water read from the schedule. The fuel cell unit 3 is held in a stopped state during the time period.

  With this configuration, since the fuel cell unit 3 is held in a stopped state during a time period in which the flow rate of the hot water read from the schedule is minimum, the operation of the fuel cell is stopped when not only the power load but also the heat demand is minimum. Thus, by shutting off the flow of gas through the meter for a second predetermined time, the fuel cell operation is avoided as a result of avoiding a meter alarm when at least one of the power load and heat demand is high. The fuel cell system can be prevented from being stopped, and the decrease in operation efficiency is minimized. The minimum flow rate of hot water read from the schedule includes not only the minimum flow rate but also a flow rate within a certain range near the minimum value including zero.

  According to the present invention, on the basis of the power consumption schedule measured by the power consumption measuring means, the fuel cell is connected to the second predetermined time after starting the operation of the fuel cell until the first predetermined time elapses. Since the fuel cell system is kept stopped for a period of time, a fuel cell system that prevents the meter from issuing an alarm can be constructed.

  Embodiments of the present invention will be described below with reference to the drawings. In each figure, the same or equivalent devices are denoted by the same reference numerals, and redundant description is omitted. In the figure, a broken line represents a control signal.

  The configuration of the fuel cell system according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram illustrating a fuel cell system 1 according to an embodiment of the present invention. The fuel cell system 1 includes a fuel cell unit 3, a hot water storage unit 4, a power consumption meter 39, a control device 9, and a battery 61 that stores electric power.

  The fuel cell unit 3 introduces a reformer 31 that introduces a commercial gas G to reform and generates a fuel gas h rich in hydrogen, and introduces a fuel gas h and an oxidant gas a containing oxygen into an electrochemical system. And a fuel cell 32 that generates water and heat by a natural reaction.

  The reformer 31 has a combustion section 31a for obtaining reforming heat necessary for reforming. The reformer 31 has a nozzle for introducing the commercial gas G, a nozzle for introducing the modifier s, and a nozzle for deriving the fuel gas h generated by the reforming reaction. Further, the combustion section 31 a has a nozzle for introducing the anode off gas p discharged from the fuel cell 32. A nozzle for deriving the fuel gas h generated by the reformer 31 is connected to the fuel electrode 32 a of the fuel cell 32. A pipe 53 is connected to the nozzle for introducing the commercial gas G, and a gas flow meter 37 and a flow rate adjustment valve 38 are arranged in the pipe 53. The pipe 53 is connected to a pipe 52 outside the fuel cell unit 3, and the meter 2 is arranged in the pipe 52.

  A signal cable is laid between the gas flow meter 37 and the control device 9. The gas flow meter 37 is configured to measure the flow rate of the gas G introduced into the reforming device 31 of the fuel cell unit 3 and transmit the measured flow rate of the gas G to the control device 9 as a signal. Yes.

  The flow rate adjusting valve 38 is an electric two-way valve, and is configured to adjust the flow rate of the gas G introduced into the reformer 31 and to block the flow of the gas G. A signal cable is laid between the flow regulating valve 38 and the control device 9. The flow rate adjustment valve 38 can control the operation and stop of the fuel cell 32 by receiving the signal from the control device 9 and controlling the introduction of the gas G to the reforming device 31 by opening and closing the valve. It is configured to be able to.

  The meter 2 has a function (safety device) that interrupts the flow of the gas G when a predetermined flow rate of gas flows for a predetermined time or more and issues an alarm when the gas continues to flow for a predetermined time, and is called a microcomputer meter. Sometimes. The meter 2 is set for a predetermined time or longer, for example, when the gas flows unnaturally in a large amount, such as when the rubber tube is removed, or when the usage time of the gas is longer than necessary, such as leaving the bath. The gas flow is automatically shut off when a gas of the flow rate of flows, and an alarm is issued when there is a crack in the rubber tube and the gas leaks and a small amount of gas continues to flow for a predetermined time. It is configured. Here, the “predetermined time” when the alarm is issued when the gas continues to flow for a predetermined time is 30 days in the present embodiment, and this corresponds to the first predetermined time. Further, even if the gas continues to flow for a predetermined time, when the flow rate is very small, it can be avoided that the meter 2 issues an alarm. In this case, the “very small amount” generally means 10 ml / Since the amount is less than about min, it is necessary to cut off the gas flow once within 30 days (first predetermined time). In addition, the meter 2 determines that there is no gas leakage when there is no gas flow for a predetermined time within 30 days, and determines that the meter 2 is normal and interrupts the 30-day measurement and starts a new 30-day measurement. In this case, the “predetermined time” is 60 minutes in the present embodiment, and this corresponds to the second predetermined time. The gas G that has passed through the meter 2 is supplied to the reformer 31, auxiliary heaters 42A and 42B, and a gas appliance 99 such as a gas stove outside the system.

  The fuel cell 32 is a polymer electrolyte fuel cell, and includes a fuel electrode 32a, an air electrode 32b, and a cooling water channel 32c. The fuel electrode 32a is provided with a nozzle for introducing the fuel gas h generated and introduced by the reformer 31, and a nozzle for discharging the anode off gas p. In the air electrode 32b, a nozzle for introducing the oxidant gas a delivered from the blower 88 and a nozzle for discharging the cathode off gas q are arranged. In the cooling water flow path 32c, a nozzle for introducing the cooling water c as a cooling fluid pumped by the circulation pump 35 and a nozzle for deriving the cooling water c are arranged.

  A signal cable is laid between the blower 88 that sends the oxidant gas a to the air electrode 32 b and the control device 9. The blower 88 receives a signal from the control device 9, adjusts the rotational speed of the rotor blade, and sends the oxidant gas a having a flow rate corresponding to the flow rate of the fuel gas h sent to the fuel electrode 32a to the air electrode 32b. It is configured.

  The fuel cell unit 3 including the reformer 31 and the fuel cell 32 further includes an inverter 33 that converts the direct current generated by the fuel cell 32 into an alternating current, and the heat generated in the fuel cell 32 is stored in the hot water storage unit 4. A heat exchanger 34 that performs heat exchange, a circulation pump 35 that circulates the cooling water c in the heat exchanger 34, and a circulation pump 36 that circulates the exhaust heat hot water t in the heat exchanger 34 and the hot water storage unit 4 are provided. Yes.

  The hot water storage unit 4 includes a hot water storage tank 41 that stores exhaust heat from the fuel cell 32 as hot water, an auxiliary heater 42A that can heat the hot water consumption u that is derived from the hot water storage tank 41 and used mainly for hot water supply, Auxiliary heater 42B that can heat circulating hot water w that is circulated for heating and bathing, hot water consumption meter 49A that measures the flow rate of consumed hot water u, and circulation that measures the flow rate of circulating hot water w And a hot water flow meter 49B.

  The hot water storage tank 41 has a nozzle for introducing exhaust hot water t whose temperature has risen at the upper part and a nozzle for deriving the hot water consumption u toward a hot water supply load such as a hot water supply appliance, and a waste heat hot water having a lower temperature at the lower part. A nozzle for deriving t toward the heat exchanger 34 is arranged. A heating element 62 that generates heat by electricity is disposed in the upper part of the hot water storage tank 41.

  The auxiliary heater 42 </ b> A is disposed in the pipe 54 through which the consumed hot water u with a high temperature derived from the hot water tank 41 flows. The auxiliary heater 42A is configured to introduce the commercial gas G through the flow rate adjustment valve 48A, burn the introduced gas, and heat the consumed hot water u flowing in the pipe 54. The flow rate adjusting valve 48A is an electric two-way valve, and is configured to adjust the flow rate of the gas G introduced into the auxiliary heater 42A and to block the flow of the gas G. A signal cable is laid between the flow rate adjusting valve 48 </ b> A and the control device 9. The flow regulating valve 48A receives the signal from the control device 9 and opens and closes the valve, thereby controlling the introduction of the gas G to the auxiliary heater 42A and controlling the temperature of the consumed hot water u flowing in the pipe 54. It is configured to be able to.

  The auxiliary heater 42B is disposed in the pipe 55 through which the circulating hot water w flows. The auxiliary heater 42B is configured to introduce the commercial gas G through the flow rate adjustment valve 48B, burn the introduced gas, and heat the circulating hot water w flowing in the pipe 55. The flow rate adjustment valve 48B is an electric two-way valve, and is configured to adjust the flow rate of the gas G introduced into the auxiliary heater 42B and to block the flow of the gas G. A signal cable is laid between the flow rate adjusting valve 48B and the control device 9. The flow rate adjusting valve 48B receives a signal from the control device 9 and opens and closes the valve, thereby controlling the introduction of the gas G to the auxiliary heater 42B and controlling the temperature of the circulating hot water w flowing in the pipe 55. It is configured to be able to.

  A temperature detector 43 is arranged in the upstream pipe 54 of the auxiliary heater 42A, and a temperature detector 44 is arranged in the downstream pipe 54, respectively. A temperature detector 45 is arranged in the upstream pipe 55 of the auxiliary heater 42B, and a temperature detector 46 is arranged in the downstream pipe 55, respectively. A signal cable is laid between each temperature detector 43, 44, 45, 46 and the control device 9. The temperature detectors 43 and 44 are each configured to detect the temperature of the consumed hot water u flowing in the pipe 54 and to transmit the detected temperature of the consumed hot water u as a signal to the control device 9. The temperature detectors 45 and 46 are configured to detect the temperature of the circulating hot water w flowing in the pipe 55 and transmit the detected temperature of the circulating hot water w as a signal to the control device 9.

  A consumed hot water flow meter 49A and a circulating hot water flow meter 49B are respectively arranged in a pipe 54 on the downstream side of the temperature detector 44 and a pipe 55 on the downstream side of the temperature detector 46. The consumed hot water flow meter 49A is configured to measure the amount of consumed hot water u derived from the hot water storage tank 41, that is, the amount of hot water supply load. The circulating hot water flow meter 49B is configured to be able to measure the amount of circulating hot water w flowing through the heating appliance and the additional cooking pipe of the bath, that is, the amount of heating load and additional cooking load (hereinafter referred to as “hot water load”). . A signal cable is laid between the consumption hot water flow meter 49A, the circulating hot water flow meter 49B and the control device 9, and the measurement result of the flow rate of the hot water measured by the consumption hot water flow meter 49A and the circulating hot water flow meter 49B. Can be transmitted to the control device 9 as signals as needed.

  The power consumption meter 39 introduces electricity generated by the fuel cell 32 and converted into alternating current by the inverter 33 and electricity E supplied from a commercial power source so as to supply electricity to power loads such as power of equipment and lamps. It is configured. The power consumption meter 39 is configured to measure how much power is loaded, how much power is generated by the fuel cell unit 3, and how much power is supplied from a commercial power source. A signal cable is laid between the power consumption meter 39 and the control device 9, and the amount of generated current measured by the power consumption meter 39 and the measurement result of the power load are transmitted to the control device 9 as needed. It is configured to be able to.

  The control device 9 receives the power load measurement signal from the power consumption meter 39 at any time, how much power load was in what time of the day, how much power was generated by the fuel cell unit 3, and from the commercial power supply. The measurement result of how much power has been supplied can be held for at least 30 days. In addition, the hot water load signal from the consumption hot water flow meter 49A and the hot water load measurement signal from the circulating hot water flow meter 49B are received at any time, and the hot water load signal and the hot water load are measured at which time of the day. The result is configured to be retained for at least 30 days. The control device 9 determines the necessary power generation amount in the fuel cell 32 and the necessary hot water amount based on the respective signals received from the power consumption meter 39, the consumed hot water flow meter 49A, and the circulating hot water flow meter 49B. Accordingly, an opening degree adjusting signal is transmitted to the flow rate adjusting valves 38, 48A, 48B, and a rotational speed adjusting signal is transmitted to the blower 88 as necessary to control operation / stop of the fuel cell system 1. Yes.

  The battery 61 is configured to be able to store surplus power when the power generated by the fuel cell unit 3 is greater than the power load. In addition, when the power generated by the fuel cell unit 3 is less than the power load or when the power load is sufficient for the amount of charge of the battery 61, the battery 61 is discharged and applied to a part or all of the power load. It is configured to be able to.

  The commercial gas G that has passed through the meter 2 is also supplied to a gas appliance 99 such as a stove outside the fuel cell system 1 other than the fuel cell unit 3 and the hot water storage unit 4 constituting the fuel cell system 1.

Next, the operation of the fuel cell system 1 will be described with reference to FIG.
In the reformer 31, the reformer s that is the reforming water and the commercial gas G that has passed through the meter 2 are introduced, and the fuel gas h rich in hydrogen by the steam reforming reaction between the reformer s and the commercial gas G. Is generated. The steam reforming reaction is an endothermic reaction, and the heat necessary for the reaction is obtained by burning the combustion gas in the combustion section 31a. The generated fuel gas h is sent to the fuel electrode 32a of the fuel cell 32.

  In the fuel cell 32, power is generated by an electrochemical reaction between the fuel gas h introduced into the fuel electrode 32a and the oxidant gas a introduced into the air electrode 32b by the blower 88 to generate water and heat. The fuel gas h and the oxidant gas a that have not been used for the reaction are discharged from the fuel cell 32 as an anode offgas p and a cathode offgas q, respectively. The anode off gas p is led to the combustion section 31a of the reformer 31, and is burned as a combustion gas in order to obtain heat necessary for the steam reforming reaction. The current generated by the fuel cell 32 is a direct current, which is converted into an alternating current by the inverter 33 and transmitted to the power consumption meter 39. Water is generated at the air electrode 32b. When the generated water is water vapor, it is mixed with the cathode offgas q and discharged. When it is water droplets, it is discharged together with the cathode offgas q by the wind pressure of the oxidant gas a. The generated heat is cooled by the cooling water c flowing through the cooling water channel 32c. The cooling water c received by the cooling water flow path 32c is pumped to the heat exchanger 34 by the circulation pump 35, and is heat-exchanged with the exhaust heat water t.

  The waste heat hot water t is sampled from a portion at a lower temperature of the hot water storage tank 41 of the hot water storage unit 4 and is pumped to the heat exchanger 34 by the circulation pump 36. The exhaust heat water t that has received heat from the cooling water c by the heat exchanger 34 and has risen in temperature is returned to the upper part of the hot water storage tank 41. The exhaust heat hot water t that has returned to the hot water storage tank 41 due to an increase in temperature is derived from the upper part of the hot water storage tank 41 toward the hot water supply load such as a mixed water tap as the consumed hot water u. The auxiliary heater 42A does not start if the temperature of the consumed hot water u derived from the hot water tank 41 is higher than the temperature required by the hot water supply load, but the temperature of the consumed hot water u derived from the hot water tank 41 requires the hot water load. If the temperature is equal to or lower than the temperature, the gas G whose flow rate is adjusted by the flow rate adjusting valve 48A is supplied to the auxiliary heater 42A, the auxiliary heater 42A is activated, and the consumed hot water u is heated to a predetermined temperature. Whether the auxiliary heater 42A is started or stopped is determined based on the temperature detected by the temperature detector 43, and the opening adjustment of the flow rate adjustment valve 48A is performed based on the temperature detected by the temperature detector 44. The flow rate of the consumed hot water u derived toward the hot water supply load is measured by the consumed hot water flow meter 49A, and the measured flow rate is transmitted to the control device 9 as needed.

  On the other hand, when a heating appliance (not shown) or a reheating bath is operated, the circulating hot water w starts to circulate, and when an operation such as a heating appliance or a reheating bath is stopped, the circulation of the circulating hot water w stops. . While the circulating hot water w is circulating, the gas G whose flow rate is adjusted by the flow rate adjusting valve 48B is supplied to the auxiliary heater 42B, the auxiliary heater 42B is activated, and the circulating hot water w is set to a predetermined temperature. Heat. The opening adjustment of the flow rate adjusting valve 48B is performed based on the temperature detected by the temperature detector 46. The flow rate of the circulating hot water w flowing is measured by the consumption hot water flow meter 49B, and the measured flow rate is transmitted to the control device 9 as needed.

  The current transmitted from the fuel cell unit 3 to the power consumption meter 39 is transmitted toward a power load such as a light (not shown) or an electric device. When the power generated by the fuel cell unit 3 is insufficient for the required power load, the shortage of power is supplied from the commercial power supply, and the power generated by the fuel cell unit 3 and the commercial power supply are supplied. The received power E is merged and transmitted to the power load. The power transmitted to the power load is measured by the power consumption meter 39, and the measured power is transmitted to the control device 9 as needed as a signal.

  As described above, the gas G supplied from the commercial gas G and passing through the meter 2 is distributed to the fuel cell unit 3, the hot water storage unit 4, the gas appliance 99 outside the fuel cell system 1, and the like. The fuel cell unit 3 tries to continue operation as long as there is an electric power load. In order to continue the operation of the fuel cell unit 3, it is necessary to continuously introduce the gas G into the reformer 31. If the flow continues for the first predetermined time (in this embodiment, 30 days) without stopping for more than the second predetermined time (60 minutes in this embodiment), the meter 2 issues an alarm and stops the alarm. The gas flow must be cut off. If the time period during which the gas flow must be interrupted to stop the alarm is a time period when the power load is heavy, the generated power of the fuel cell unit 3 cannot be used and the operation efficiency is lowered. In addition, since the fuel cell takes a considerable amount of time to start and return to the steady operation after being stopped once, an efficient fuel cell system 1 is obtained when a time zone with a large power load comes in the time until the steady operation is started. Can no longer drive. Moreover, when the time zone in which the gas flow must be shut off to stop the alarm is a time zone during which there are many hot water supply loads or hot water loads, the gas supplied to the auxiliary heaters 42A and 42B is also shut off. Therefore, it becomes impossible to raise the temperature of the consumed hot water u and the circulating hot water w to the required temperature.

  In order to avoid such an inconvenience, the fuel cell system 1 has a minimum power load within a first predetermined time (30 days in the present embodiment) after the operation of the fuel cell system 1 is started. The fuel cell unit itself when the hot water storage unit 4 actually has an expected amount of heat to be used on the load side read from the schedule in a time zone where the fuel cell unit 3 is less than the minimum output and the hot water supply load and the hot water load are expected to be minimum. The fuel cell caused by shutting off the gas flow to stop the alarm issued by the meter 2 during the time when there is a lot of electric power load, hot water supply load and hot water load by stopping the operation of 3 (so-called learning control) It is intended to prevent a decrease in the operational efficiency of the system 1. In general, it is considered that the time zone in which the power load is minimum is a time zone in which a person is not active, and the gas appliance 99 or the like is not used. Hereinafter, the flow leading to stopping the operation of the fuel cell unit 3 by itself will be described with reference to FIGS. In addition, about the code | symbol of the structure used by the following description, FIG. 1 shall be referred suitably.

FIG. 2 is a flowchart for explaining the operation of stopping the fuel cell unit 3 for the second predetermined time after the start of operation until the first predetermined time elapses.
The control device 9 acquires the power consumption amount, the consumption hot water amount, and the circulating hot water amount based on the signals received from the power consumption meter 39, the consumption hot water flow meter 49A, and the circulation hot water flow meter 49B, respectively. The calorific value is calculated from the amount of power generated by the fuel cell unit 3 and the amount of heat stored in the hot water storage unit 4 is calculated and acquired every time period from the start of operation of the fuel cell unit 3 until 27 days have passed. The calculated result is held (S201).

  In consideration of the fact that the transition of the daily power load is generally different depending on the place where electricity is used (such as each household) and each day, 27 days have passed since the start of the fuel cell unit 3. The control device 9 holds the transition of the power load. As the transition of the power load, for example, the one shown in FIG. 3 is grasped. In FIG. 3, electricity is always used throughout the day, but the amount of use from 6 o'clock to 9 o'clock and from 17 o'clock to 23 o'clock is large, and the peak of electricity use is around 18:00. Conversely, the usage from 2 o'clock to 6 o'clock and from 10 o'clock to 17 o'clock is relatively small. Note that the time required from the start of the fuel cell unit 3 to the steady operation is also grasped.

  Similarly to grasping the transition of the electric power load, the transition of the hot water supply load, the hot water load, and the heat storage amount is also held in the control device 9. As a transition of the hot water supply load, for example, the one shown in FIG. 4 is grasped. In FIG. 4, hot water is used from 6 o'clock to 8 o'clock and from 17 o'clock to 21:30, and is used intermittently from 22:00 to 23:30. The transition of the hot water load is also grasped in the same manner as the electric power load and the hot water supply load, but not shown as an example, and is held in the control device 9. Moreover, the transition of the heat storage amount is estimated from the transition of the hot water supply load, the hot water load, and the power load, and is held in the control device 9.

  From the acquisition and calculation results of power consumption, hot water consumption, circulating hot water consumption, and heat storage amount for each day / time zone for 27 days, a candidate for a time zone in which the fuel cell unit 3 can be stopped with the least decrease in operation efficiency is obtained. Extract (S202). The time period during which the fuel cell unit 3 can be stopped with the least decrease in operation efficiency is typically the expected power load is the minimum or less than the minimum output of the fuel cell unit 3, and the hot water supply load and the hot water load are the minimum. Necessary from the start of the fuel cell unit 3 to the steady operation within the second predetermined time (60 minutes in the present embodiment) during which it is possible to interrupt the measurement of the time until the meter 2 issues an alarm. This is a case where the amount of heat used on the load side read from the schedule is in the hot water storage unit 4 in a time zone of 110 minutes or more including a long time (for example, 50 minutes). For example, in the example shown in FIGS. 3 and 4, it is from 2 o'clock to 6 o'clock and from 10 o'clock to 17 o'clock.

  Here, when there are a plurality of candidate time zones in which the fuel cell unit 3 can be stopped, the time zone in which the hot water supply load is expected to be small in a certain time zone after the fuel cell unit 3 is restarted is selected. As described above, once the fuel cell is stopped, it takes a considerable time to start and return to the steady operation, but during this time, the exhaust heat of the fuel cell cannot be used. That is, if the fuel cell unit 3 is stopped in a time zone where a relatively large hot water supply load is expected after the fuel cell unit 3 is restarted, the load may fluctuate depending on the day. When the amount of water increases, the amount of hot water stored in the hot water storage tank 41 may be insufficient, and in this case, the operation efficiency of the fuel cell system 1 is reduced. On the other hand, if the fuel cell unit 3 is stopped during a time period when a relatively small hot water supply load is expected after the restart of the fuel cell unit 3, the amount of hot water stored in the hot water storage tank 41 is insufficient for the required hot water supply load. Is unlikely to happen. From this point of view, in the present embodiment, it is preferable to set the time from 2 o'clock to 6 o'clock as a candidate time for which the fuel cell unit 3 can be stopped.

  In addition, as another criterion for determining which time zone to stop when there are a plurality of candidate time zones in which the fuel cell unit 3 can be stopped, select a time zone in which the fuel cell unit 3 is stopped for a short time. Also good. In general, a fuel cell is less efficient when operated at low power than at high power. In addition, since the fuel cell consumes fuel that is not used for power generation such as preheating when starting and stopping, it is better that the number of times of starting and stopping is small. That is, when the fuel cell unit 3 is operated with low power load and low output operation, it may be better to stop the fuel cell unit 3 until the power load increases once the fuel cell unit 3 is stopped. On the other hand, since the hot water stored in the heat storage tank 41 dissipates heat over time, the amount of heat stored in the hot water storage tank 41 decreases unless the exhaust heat of the fuel cell unit 3 is stored in the hot water storage tank 41. Therefore, from the viewpoint of suppressing loss due to heat radiation in the heat storage tank 41, it is preferable that the time for stopping the fuel cell unit 3 is shorter after the second predetermined time is exceeded. Also from this point of view, in the present embodiment, it is preferable to set the time from 2 o'clock to 6 o'clock as a candidate time when the fuel cell unit 3 can be stopped.

  If there are a plurality of candidate time zones in which the fuel cell unit 3 can be stopped and the above advantages do not coincide with one time zone, the fuel cell unit 3 is stopped at a candidate time in which any fuel cell unit 3 can be stopped. This can be selected as appropriate by the user of the fuel cell system 1 setting the control device 9 in advance.

  Returning to the description of the flow from here to the stop of the operation of the fuel cell unit 3 again. When it becomes a candidate time (for example, 2 o'clock to 2:10 o'clock) that can stop the fuel cell unit 3 on the 28th day, the power load is equal to or less than a predetermined power (the power load is the minimum or the minimum output of the fuel cell unit 3). In addition, it is determined whether or not the hot water storage unit 4 has the amount of heat used on the load side read from the schedule while the hot water supply load and the hot water load are at a minimum (S203). A step of stopping the fuel cell unit 3 if the electric power load is equal to or lower than the predetermined electric power and the hot water supply load and the hot water load are at a minimum, and the amount of heat used on the load side read from the schedule is in the hot water storage unit 4 (S205). If not, the process proceeds to the next step (S204).

  It is determined whether or not a candidate time (for example, 2:00 to 2:10) that can stop the fuel cell unit 3 on the 29th day has come (S204). Then, regardless of whether or not the amount of heat used on the load side read from the schedule is in the hot water storage unit 4 in a state where the power load is equal to or less than the predetermined power and the hot water supply load and the hot water load are minimum, the fuel cell unit 3 The process proceeds to the step of stopping (S205). Electric power when the fuel cell unit 3 is stopped is supplied from a commercial power source. If the fuel cell unit 3 is stopped when the power load is equal to or lower than the predetermined power and the hot water supply load and the hot water load are not at a minimum state, it cannot be said that the operation efficiency of the fuel cell system 1 is good. The operation efficiency of the fuel cell system 1 can be reduced less than when the hot water load is automatically stopped at a time when the hot water load is large.

  When the fuel cell unit 3 is stopped, measurement of a second predetermined time (60 minutes in the present embodiment), which is a time during which measurement of the time until the meter 2 issues an alarm, can be started (S206). After the measurement of the second predetermined time is started, the process proceeds to a step (S207) for determining whether or not the second predetermined time has elapsed. If the second predetermined time has elapsed, the process proceeds to a step of restarting the fuel cell unit 3 (S209). If not, the process proceeds to the next step.

  If the second predetermined time has not elapsed, it is determined whether or not the auxiliary heater 42A or 42B has been used (S208). If the auxiliary heater 42A or 42B is not used, the process returns to the step of determining whether or not the second predetermined time has elapsed (S207), and if the auxiliary heater 42A or 42B is used, the second predetermined time is measured. Returning to step (S205), the second predetermined time is measured again from the beginning.

  When the second predetermined time or more has elapsed since the start of measurement, the fuel cell unit 3 is restarted (S209). When the fuel cell unit 3 is restarted, the control device 9 holds the acquisition and calculation results of the power consumption amount, the hot water consumption amount, the circulating hot water amount, and the heat storage amount for each time period until the 27th day again. The process returns to step (S201). Thereafter, the above series of operations is repeated until the fuel cell unit 3 stops for a second predetermined time or longer.

  In the above description, the reforming method has been described as the steam reforming method, but it may be a partial oxidation reforming method or an autothermal reforming method. When the partial oxidation reforming method or the autothermal reforming method is adopted, the combustion part 31a is not necessary, and the fuel cell unit 3 can be made compact.

  In the above description, the first predetermined time is 30 days and the second predetermined time is 60 minutes. However, it is needless to say that the first predetermined time is not limited to these.

  In the above description, the candidate time zone for stopping the fuel cell unit 3 is determined based on the electric power load, the hot water supply load, and the hot water load. However, the fuel cell is based only on the electric power load or based on the electric power load and the hot water supply load. It goes without saying that a candidate for a time zone for stopping the unit 3 may be determined.

  In the above description, the preliminary day is provided after the 27th day, but from the viewpoint of extending the period until the stop, it may be set to stop at a time when the load on the 30th day is small.

  As described above, the fuel cell system 1 according to the present embodiment suppresses the stoppage of the gas flow to the minimum without invalidating the protection function of the meter 2, and the fuel cell system 1 is used when the gas flow is stopped. A decrease in operational efficiency of the battery system 1 can be suppressed.

1 is a block diagram illustrating a fuel cell system 1 according to an embodiment of the present invention. It is a flowchart explaining the operation | movement which stops for a 2nd predetermined time before the 1st predetermined time passes after the driving | operation start of a fuel cell unit. It is a graph showing transition of the electric power load of a certain day. It is a graph showing transition of the hot water supply load of a certain day.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 2 Meter 3 Fuel cell unit 4 Hot water storage unit 9 Control device 31 Reformer 32 Fuel cell 39 Power consumption meter 49A Consumption hot water flow meter 49B Circulation hot water flow meter G Commercial gas h Fuel gas t Waste heat water u Consumption hot water w Circulating hot water

Claims (5)

A reformer that introduces a commercial gas that has passed through a meter that issues an alarm when the gas continues to flow for a predetermined time and reforms the commercial gas to produce a hydrogen-rich fuel gas, and introduces the fuel gas into an electrochemistry A fuel cell unit having a fuel cell that generates electric power to be supplied to the load side by a thermal reaction and generates heat;
Power consumption measuring means for measuring power consumption used on the load side;
A control device for controlling the start and stop of the fuel cell unit, wherein a first predetermined time after starting the operation of the fuel cell unit based on a schedule of power consumption measured by the power consumption measuring means A control device that holds the fuel cell unit in a stopped state for a second predetermined period of time until it has elapsed;
Fuel cell system. The control device is a time zone in which the power consumption read from the schedule is a minimum time period or a time period in which the power consumption is less than a minimum output of the fuel cell unit, and the power consumption measured by the power consumption measurement unit is Holding the fuel cell unit in a stopped state when it is below a predetermined power;
The fuel cell system according to claim 1. A hot water storage unit for storing heat generated in the fuel cell using hot water as a medium;
Hot water flow rate measuring means for measuring the flow rate of hot water derived from the hot water storage unit toward the load side;
Based on the schedule of the flow rate of hot water measured by the hot water flow rate measuring means, the fuel cell unit is moved to the second predetermined time after the start of the operation of the fuel cell unit until the first predetermined time elapses. A control device for holding in a stopped state for a period of time;
The fuel cell system according to claim 1 or 2. The control device holds the fuel cell unit in a stopped state when the amount of heat used on the load side read from the schedule is in the hot water storage unit;
The fuel cell system according to claim 3. The control device holds the fuel cell unit in a stopped state in a time zone in which the flow rate of the hot water read from the schedule is minimized;
The fuel cell system according to claim 3 or 4.

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