JP5518165B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system including a fuel cell, and in particular, a fuel capable of storing hot water generated by using exhaust heat of a fuel cell in a hot water storage tank and providing it for uses such as hot water supply and heating. The present invention relates to a battery system.

  Conventionally, a fuel cell system capable of high-efficiency small-scale power generation has a relatively simple configuration for using thermal energy generated during power generation operation, so it can achieve high energy utilization efficiency. As a decentralized power generation system, intensive development is underway.

  The fuel cell system includes a fuel cell stack (hereinafter simply referred to as “fuel cell”) as a main body of the power generation unit. In this fuel cell, during power generation operation, a fuel gas containing hydrogen is supplied to the anode side, and an oxidant gas containing oxygen is supplied to the cathode side. In this fuel cell, hydrogen and oxygen contained in the fuel gas and the oxidant gas are used, and a predetermined electrochemical reaction proceeds. Thus, a predetermined electrochemical reaction proceeds in the fuel cell, so that the fuel cell system supplies desired power toward the load.

  By the way, during the power generation operation of the fuel cell system, in the fuel cell, thermal energy is generated as a predetermined electrochemical reaction proceeds. On the other hand, in a fuel cell system, in order for the fuel cell to suitably perform a power generation operation, the temperature of the fuel cell becomes a temperature within a predetermined temperature range in order to allow a predetermined electrochemical reaction to proceed appropriately in the fuel cell. Need to be controlled. Therefore, the fuel cell system is provided with a cooling configuration for cooling the fuel cell. In this cooling configuration, for example, cooling water from which impurities such as metal ions are sufficiently removed is circulated between the fuel cell and the radiator. Thereby, since the heat energy generated in the fuel cell is discharged through the cooling water and the radiator, the progress of the predetermined electrochemical reaction is preferably ensured, and thus the power generation operation of the fuel cell system is suitably ensured. .

  However, if the thermal energy generated in the fuel cell is simply discharged via the cooling water and the radiator, the operating temperature of the fuel cell can be controlled to an appropriate operating temperature, but the thermal energy is used effectively. Therefore, the energy utilization efficiency of the fuel cell system is significantly reduced.

  Therefore, by actively using the heat energy generated during power generation operation and realizing high energy use efficiency, the heat energy discharged from the fuel cell during power generation operation is supplied to the heat exchanger. There has been proposed a fuel cell system capable of storing generated hot water in a hot water storage tank and providing it for uses such as hot water supply and heating (for example, see Patent Document 1).

  FIG. 9 is a block diagram schematically showing the configuration of a conventional fuel cell system.

  As shown in FIG. 9, the conventional fuel cell system 500 includes a power generation unit 101, exhaust heat recovery means 106, and a hot water storage tank 104. Here, the power generation unit 101 includes a reformer 102 and a fuel cell 103. The exhaust heat recovery means 106 includes a sensible heat recovery heat exchange unit 109, a cooling water exhaust heat recovery heat exchange unit 110, and a latent heat recovery heat exchange unit 111. The sensible heat recovery heat exchanging unit 109 recovers sensible heat of the exhaust gas containing water vapor discharged from the reformer 102. Further, the cooling water exhaust heat recovery heat exchange unit 110 of the exhaust heat recovery means 106 recovers the exhaust heat of the cooling water after cooling the fuel cell 103. In addition, the latent heat recovery heat exchange unit 111 of the exhaust heat recovery means 106 recovers the latent heat accompanying the condensation of water vapor after the sensible heat recovery heat exchange unit 109 recovers the sensible heat.

  As shown in FIG. 9, in this conventional fuel cell system 500, a part of the circulation pipe 105 connecting the lower side and the upper side of the hot water storage tank 104 in FIG. 9 is sensible heat recovery heat of the exhaust heat recovery means 106. It is arranged inside the exchange unit 109, the cooling water exhaust heat recovery heat exchange unit 110, and the latent heat recovery heat exchange unit 111. Further, a part of the annular circulation pipe 112 is disposed inside the fuel cell 103 and the cooling water exhaust heat recovery heat exchange unit 110.

  Here, although not shown in FIG. 9, in the cooling water exhaust heat recovery heat exchange unit 110 of the conventional fuel cell system 500, water flowing through the circulation pipe 105 (hereinafter including water stored in the hot water storage tank 104, In order to prevent mixing of the hot water and the cooling water (collectively referred to as “hot water”) into the cooling water flowing through the circulation pipe 112 (one form of cross connection), the hot water and the cooling water can transfer heat. A heat exchange wall is provided that is separated by The sensible heat recovery heat exchange unit 109 and the latent heat recovery heat exchange unit 111 are also provided with heat exchange walls for preventing the hot water from being mixed into the exhaust gas and water vapor.

  In such a conventional fuel cell system 500, during the power generation operation, the hot water flowing through the circulation pipe 105 is transferred to the latent heat recovery heat exchange unit 111, the cooling water exhaust heat recovery heat exchange unit 110, and the sensible heat recovery of the exhaust heat recovery means 106. The heat exchange unit 109 is sequentially heated. Then, the hot water heated by the exhaust heat recovery means 106 is stored in the hot water storage tank 104. Hot water stored in the hot water storage tank 104 is provided for uses such as hot water supply and heating.

JP 2002-289213 A (page 2-3, FIG. 1)

  However, in the configuration of the proposed conventional fuel cell system 500, when a crack due to corrosion occurs in a part of the heat exchange wall of the cooling water exhaust heat recovery heat exchange unit 110, the circulation pipe 105 is passed. The stored hot water may be mixed into the cooling water flowing through the circulation pipe 112. In this case, since hot water (city water) containing impurities such as metal ions is mixed in the cooling water, the conductivity of the cooling water is increased, and electric leakage occurs in the fuel cell 103. In general, since the water pressure in the circulation pipe 105 connected to the hot water storage tank 104 that is vertically high is relatively high, there is a high risk that hot water is mixed into the circulation pipe 112 from the circulation pipe 105.

  In addition, when cracks due to corrosion occur in some of the heat exchange walls of the sensible heat recovery heat exchange unit 109 and the latent heat recovery heat exchange unit 111, the hot water stored in the circulation pipe 105 is discharged from the reformer 102. In some cases, the exhaust gas is mixed into the exhaust gas and the water vapor exhausted from the sensible heat recovery heat exchange unit 109. In this case, the hot water is supplied to the latent heat recovery heat exchange unit 111 together with the exhaust gas, and is discarded from the fuel cell system 500 together with the condensed water from the latent heat recovery heat exchange unit 111.

  In other words, the configuration of the proposed conventional fuel cell system 500 does not include a means for detecting the occurrence of cracks in the exhaust heat recovery means 106 when cracks due to corrosion occur in part of the heat exchange wall. In addition, electric leakage in the fuel cell 103 and leakage of hot water from the circulation pipe 105 are continued.

  The present invention has been made to solve the above-described conventional problems, and provides a fuel cell system capable of detecting the occurrence of a cross connection in a heat exchanging means and preventing an abnormal operation state from continuing. For the purpose.

In order to solve the above-described conventional problems, a characteristic fuel cell system according to the present invention is a fuel cell that generates power using a fuel gas and an oxidant gas, and recovers exhaust heat related to power generation of the fuel cell. A hot water storage tank for storing hot water to be stored, a combustor for combusting fuel gas discharged from the fuel cell , hot water stored in the hot water storage tank, fuel gas or oxidant gas discharged from the fuel cell, or A heat exchanger for exchanging heat with the flue gas discharged from the combustor, and condensation from the fuel gas or the oxidant gas or the flue gas after exchanging heat with the hot water in the heat exchanger and condensed water tank for storing water, a water level sensor for detecting the water level of the condensed water tank, and an abnormality alarm to the water level sensor is informed of the abnormality on the basis of the water level to detect, before Symbol condensed Mizuta Water ejector to change more level of the condensed water tank to the exit of water discharge from the click, by the water level sensor when the fuel cell is stopped driving with a pre Kisui halted the ejector and a control unit which Ru is informed of the abnormality by the abnormality alarm and increase of the water level is detected in the condensed water tank.

With such a configuration, the control device causes the abnormality notification device to notify the occurrence of abnormality based on the abnormal change in the water level in the water tank detected by the water level sensor, so that the occurrence of cross connection in the heat exchanger is detected. It becomes possible. In addition, with such a configuration, since the abnormality alarm is informed of the occurrence of an abnormality by a simple configuration in which the water level sensor detects an increase in the water level in the water tank while the operation of the water level changer is stopped, It becomes possible to accurately detect that a connection has occurred. Further, with such a configuration, a heat exchanger for exchanging heat between the fuel gas or oxidant gas discharged from the fuel cell and the cooling water for cooling the fuel cell, the fuel gas after heat exchange in the heat exchanger, or It is possible to detect that a cross connection has occurred in a heat exchanger in a general fuel cell system having a condensed water tank for storing condensed water from an oxidant gas and a water discharger for discharging water from the condensed water tank. It becomes possible. Further, with such a configuration, a combustor that burns fuel gas discharged from the fuel cell, a heat exchanger that exchanges heat with the combustion exhaust gas discharged from the combustor, and combustion after heat exchange in the heat exchanger It is possible to detect the occurrence of cross connection in a heat exchanger in a general fuel cell system equipped with a condensed water tank that stores condensed water from exhaust gas and a water discharger that discharges water from the condensed water tank. Become.

  Here, in any of the above cases, the system further includes an operation controller that controls the operation of the fuel cell system, and the operation controller is configured to cause the fuel to be generated when the controller notifies the abnormality notification of the occurrence of the abnormality. Stop battery system operation.

  With this configuration, since the control device stops the operation of the fuel cell system when the abnormality alarm notifies the occurrence of the abnormality, the fuel cell continues to leak, or the water tank from the hot water tank through the heat exchanger It is possible to prevent the stored hot water supplied to the water from being continuously discarded.

  In any of the above cases, the fuel cell system further includes an operation controller that controls the operation of the fuel cell system, and the operation controller is configured when the controller detects an increase in the water level using the water level sensor. The fuel cell system is not permitted to shift from operation stop to operation start.

  With this configuration, the operation controller does not allow the transition from the stop of the operation of the fuel cell system to the start of operation when a water level rise is detected by the water level sensor. It becomes possible to prevent the fuel cell system from being started or restarted.

  According to the characteristic configuration of the fuel cell system according to the present invention, it is possible to provide a fuel cell system capable of detecting the occurrence of cross connection in the heat exchange means and preventing the abnormal operation state from continuing. become.

FIG. 1 is a block diagram schematically showing the configuration of the fuel cell system according to Embodiment 1 of the present invention. FIG. 2 is a block diagram schematically showing the configuration of the fuel cell system according to Embodiment 2 of the present invention. FIG. 3 is a flowchart schematically showing a characteristic operation of the fuel cell system according to Embodiment 2 of the present invention. FIG. 4 is a flowchart schematically showing a characteristic operation of the fuel cell system according to Embodiment 3 of the present invention. FIG. 5 is a block diagram schematically showing the configuration of the fuel cell system according to Embodiment 4 of the present invention. FIG. 6 is a flowchart schematically showing a characteristic operation of the fuel cell system according to Embodiment 4 of the present invention. FIG. 7 is a flowchart schematically showing a characteristic operation of the fuel cell system according to Embodiment 5 of the present invention. FIG. 8 is a block diagram schematically showing the configuration of the fuel cell system according to Embodiment 6 of the present invention. FIG. 9 is a block diagram schematically showing the configuration of a conventional fuel cell system.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
First, the configuration of the fuel cell system according to Embodiment 1 of the present invention will be described.

  FIG. 1A is a block diagram schematically showing the configuration of the fuel cell system according to Embodiment 1 of the present invention. In FIG. 1A, only components necessary for explaining the present invention are extracted and illustrated, and other components are not shown.

  As shown in FIG. 1A, a fuel cell system 100 according to the present embodiment includes a fuel cell 1 that generates power using a hydrogen-rich fuel gas and an oxidant gas (air) containing oxygen, and the fuel. A cooling water tank 2 for storing cooling water for recovering heat generated during power generation operation of the battery 1 and performing temperature control thereof, and cooling water between the cooling water tank 2 and the fuel cell 1 Is provided with a cooling water flow path 3 and a cooling water circulation pump 4.

  Further, the fuel cell system 100 includes a heat exchanger 5 that cools the temperature-increased cooling water that is passed through the cooling water flow path 3 by the cooling water circulation pump 4 by heat exchange with the hot water storage, and is cooled in the heat exchanger 5. Hot water storage tank 6 for storing hot water whose temperature has been raised by heat exchange with water together with city water supplied from the supply source, and hot water storage for circulating hot water between the hot water storage tank 6 and heat exchanger 5 A water passage 7 and a hot water circulation pump 8 are provided.

  Furthermore, the fuel cell system 100 includes a water level sensor 9 for detecting the water level of the cooling water in the cooling water tank 2, and a water level sensor 12 for detecting a water level higher than the water level that can be detected by the water level sensor 9. A replenishing water tank 10 for storing cooling water to be replenished to the cooling water tank 2, a replenishing water valve 11a for replenishing cooling water from the replenishing water tank 10 to the cooling water tank 2 and shutting it off, A discharge water valve 11b for discharging and blocking the cooling water from the cooling water tank 2, and opening / closing states of the discharge water valve 11b and the replenishing water valve 11a are controlled according to the water level detected by the water level sensor 9. The amount of cooling water supplied from the makeup water tank 10 to the cooling water tank 2 and the amount of cooling water discharged from the cooling water tank 2 are controlled by the water level sensor 12 and And a control unit 13 for monitoring the abnormality of the water level of the cooling water. Here, the control part 13 is provided with the abnormality indicator 13a for alerting | reporting the abnormal change of the water level resulting from generation | occurrence | production of cross connection. In addition, the control unit 13 includes a water level controller 13b that controls operations of the makeup water valve 11a and the discharge water valve 11b based on output signals of the water level sensor 9 and the water level sensor 12.

  1A, in the fuel cell system 100 according to the present embodiment, the fuel cell 1, the cooling water tank 2, the cooling water circulation pump 4, and the heat exchanger 5 are annularly formed by the cooling water flow path 3. It is connected to. In this fuel cell system 100, the heat exchanger 5, the hot water storage tank 6, and the hot water storage water circulation pump 8 are connected in an annular shape by the hot water storage water flow path 7. On the other hand, the makeup water tank 10 and the cooling water tank 2 are connected by piping, and other piping is connected to the cooling water tank 2, and a makeup water valve 11a and a discharge water valve 11b disposed on these pipings. The water level sensor 9 and the water level sensor 12 are electrically connected to the control unit 13 by wiring.

  In the fuel cell system 100 according to the present embodiment, the heat exchanger 5 is a specific heat exchanger that exchanges heat between the hot water stored in the hot water storage tank 6 and the cooling water discharged from the fuel cell 1. The cooling water tank 2 is an example of a specific embodiment of a water tank that stores cooling water after heat exchange with hot water in the heat exchanger 5, and is a replenishment water valve 11a. The discharge water valve 11b is an example of a specific embodiment of a water level changer that changes the water level in the cooling water tank 2 by supplying water to the cooling water tank 2 or discharging water.

  Moreover, the abnormality indicator 13a is an example of a specific embodiment of an abnormality notification device that notifies the occurrence of an abnormality caused by the occurrence of a cross connection by displaying it as visual information.

  In the present embodiment, the heat generated during the power generation operation of the fuel cell 1 is an example of exhaust heat related to the power generation of the fuel cell 1. On the other hand, the cooling water stored in the cooling water tank 2 is an example of an exhaust heat intermediate fluid related to power generation of the fuel cell 1.

  In the present embodiment, the control unit 13 does not separately provide the water level controller 13b in the control unit 13, and the control unit 13 operates the supply water valve 11a and the discharge water valve 11b based on the output signals of the water level sensors 9 and 12. You may comprise so that it may function also as a water level controller which controls and controls the water level of the cooling water tank 2. FIG.

  Next, a modification of the fuel cell system according to Embodiment 1 of the present invention will be described.

  FIG. 1B is a block diagram schematically showing a part of a modification of the fuel cell system according to Embodiment 1 of the present invention. In FIG. 1B, only the characteristic configuration (difference) in the modified example of the fuel cell system is extracted and illustrated.

  As shown in FIG.1 (b), in the modification of the fuel cell system 100 which concerns on this Embodiment, it replaces with the drainage valve 11b shown to Fig.1 (a) and the wiring connected to it, and the overflow pipe 2a is provided. Is provided. The overflow pipe 2 a is provided at a predetermined position in the vertical direction on the side wall surface of the cooling water tank 2. The overflow pipe 2a is configured such that when the water level of the cooling water in the cooling water tank 2 rises and the water level rises to the connecting position of the overflow pipe 2a, the cooling water is supplied from the cooling water tank 2 to the water level controller of the control unit 13. It is automatically discharged without being controlled by 13b and returned to the makeup water tank 10. By means of the overflow pipe 2a, the water level sensor 9, the makeup water tank 10, the makeup water valve 11a, and the water level controller 13b of the control unit 13, the water level in the cooling water tank 2 is appropriately set within a predetermined or predetermined range. Be controlled.

  Here, in the fuel cell system 100 and its modification according to the present embodiment, although not shown in FIGS. 1 (a) and 1 (b), the cooling water tank 2 passes through the discharge water valve 11b or the overflow pipe 2a. The discharged cooling water is once stored in a condensed water tank. The cooling water stored in the condensed water tank is purified by an ion exchange device (not shown) and then supplied to the makeup water tank 10. The cooling water supplied to the replenishing water tank 10 is supplied to the cooling water tank 2 via the replenishing water valve 11a.

  In the present embodiment, the form in which the makeup water tank 10 and the condensed water tank (not shown) are separately provided is illustrated, but the present invention is not limited to such a form. For example, the cooling water discharged from the cooling water tank 2 through the discharge water valve 11b or the overflow pipe 2a may be directly supplied to the makeup water tank 10. That is, the makeup water tank 10 may function as a condensed water tank (or the condensed water tank functions as the makeup water tank 10). In this case, the cooling water stored in the makeup water tank 10 is purified by an ion exchange device (not shown) in order to prevent leakage of electricity in the fuel cell 1 and the like. To the cooling water tank 2.

  Next, the basic operation of the fuel cell system 100 according to the present embodiment will be described.

  In the fuel cell system 100 according to the present embodiment, the power generation operation is performed by supplying the fuel cell 1 with hydrogen-rich fuel gas and oxygen-containing oxidant gas. At this time, the fuel cell 1 outputs DC power instead of AC power. Therefore, the DC power output from the fuel cell 1 is input to an inverter (not shown). The DC power output from the fuel cell 1 is converted into AC power by an inverter, and then supplied to an electric power load (not shown) that receives power supply from the fuel cell system 100.

  During the power generation operation of the fuel cell system 100, the fuel cell 1 generates heat simultaneously with the generation of DC power. The heat generated in the fuel cell 1 is sequentially recovered by the cooling water circulating through the cooling water flow path 3 by operating the cooling water circulation pump 4. Specifically, the cooling water is passed through the fuel cell 1 and heat exchange is performed between the cooling water and the fuel cell 1, whereby the heat generated in the fuel cell 1 is sequentially recovered by the cooling water. Thereby, since the fuel cell 1 is cooled, the temperature is appropriately controlled. The cooling water whose temperature has been increased by heat exchange with the fuel cell 1 is passed through the heat exchanger 5. The cooling water is cooled by heat exchange with the hot water in the heat exchanger 5 and then returned to the cooling water tank 2. The cooling water returned to the cooling water tank 2 is sent again by the cooling water circulation pump 4 and supplied again to the fuel cell 1.

  Further, during this power generation operation, in the fuel cell system 100, hot water stored in the hot water storage tank 6 is passed through the hot water storage passage 7 by operating the hot water circulation pump 8. Circulated. Specifically, the hot water supplied from the hot water storage tank 6 to the hot water passage 7 is supplied to the heat exchanger 5 after passing through the hot water circulation pump 8. Then, in this heat exchanger 5, the hot water is heated by exchanging heat with the high-temperature cooling water circulated in the cooling water flow path 3. The heated hot water stored in the hot water further passes through the hot water storage passage 7 and is stored in the hot water storage tank 6. The hot water stored in the hot water storage tank 6 is appropriately supplied from the upper part of the hot water storage tank 6 to a hot water supply equipment (not shown) for hot water supply or hot water heating as required. .

  On the other hand, during the power generation operation of the fuel cell system 100, when the water level sensor 9 detects a decrease in the water level in the cooling water tank 2 due to evaporation of the cooling water or the like, the water level controller 13b of the control unit 13 receives the detection signal. Activates the makeup water valve 11a. Thereby, the cooling water stored in the makeup water tank 10 is supplied to the cooling water tank 2. The water level controller 13b of the control unit 13 receives the detection signal when the water level sensor 9 detects the return of the water level by the replenishing operation of the cooling water, and shuts off the replenishing water valve 11a. Thereby, the water level controller 13b of the control unit 13 stops the replenishment operation of the cooling water from the replenishing water tank 10 to the cooling water tank 2.

  Further, during the power generation operation of the fuel cell system 100, when the cooling water is excessively supplied from the makeup water tank 10 to the cooling water tank 2, and the water level sensor 9 detects an increase in the water level in the cooling water tank 2, In response to the detection signal, the water level controller 13b of the control unit 13 operates the discharge water valve 11b. Then, when the water level sensor 9 detects the return of the water level by the cooling water discharging operation by the discharge water valve 11b, the water level controller 13b of the control unit 13 receives the detection signal and blocks the discharge water valve 11b. Alternatively, during the power generation operation of the fuel cell system 100, the cooling water is excessively supplied from the makeup water tank 10 to the cooling water tank 2, and the cooling water level in the cooling water tank 2 reaches the connecting position of the overflow pipe 2a. In this case, the cooling water further supplied from the makeup water tank 10 is discharged via the overflow pipe 2a. As a result, the water level of the cooling water in the cooling water tank 2 is appropriately adjusted.

  Next, regarding the operation of the fuel cell system 100 according to the present embodiment, a characteristic operation for detecting the occurrence of cross connection in the heat exchanger 5 will be described.

  During normal operation of the fuel cell system 100, the control unit 13 uses the water level sensor 9, the makeup water tank 10, the makeup water valve 11a, the discharge water valve 11b, the overflow pipe 2a, and the like to appropriately use the cooling water. The water level in the tank 2 is appropriately controlled within a fixed or predetermined range.

  However, when a crack occurs in a part of a heat exchange wall (not shown) of the heat exchanger 5 due to, for example, corrosion and a cross connection occurs in the heat exchanger 5 due to the occurrence of the crack, The stored hot water flowing through 7 flows through the cracks generated in the heat exchanger 5 and flows into the cooling water passage 3.

  In this case, when the makeup water valve 11a and the discharge water valve 11b are shut off (see FIG. 1 (a)) or when the makeup water valve 11a is shut off (see FIG. 1 (b)), Since the stored hot water continuously flows into the cooling water flow path 3, the water level of the cooling water tank 2 rises to a water level exceeding the water level sensor 9. Specifically, in a state where there is no replenishment of cooling water from the replenishing water tank 10 and no cooling water discharge from the cooling water tank 2, the water level in the cooling water tank 2 exceeds the upper limit of the water level detection range of the water level sensor 9. The water level sensor 12 rises abnormally to the water level within the water level detection range. Such an abnormal rise in the water level in the cooling water tank 2 (an abnormal change in the water level in the cooling water tank 2) is a phenomenon that is typically observed when a cross connection occurs in the heat exchanger 5. is there.

  Therefore, in the present embodiment, the fuel cell 1, the hot water storage tank 6, the heat exchanger 5, the cooling water tank 2, the water level sensor 9, the water level sensor 12, the makeup water tank 10, the makeup water valve 11a, In the fuel cell system 100 including the discharge water valve 11b and the control unit 13, the control unit 13 cross-connects to the abnormality indicator 13a based on an abnormal change in the water level in the cooling water tank 2 detected by the water level sensor 12. The occurrence of an abnormality caused by the occurrence of an error is notified.

  Specifically, when the control unit 13 controls the supply water valve 11a and the discharge water valve 11b to shut off, when the water level sensor 12 detects an abnormal rise in the water level in the cooling water tank 2, an abnormality display is displayed. The device 13a is notified of the occurrence of an abnormality caused by the occurrence of the cross connection.

  Alternatively, when the water discharger of the cooling water tank 2 is the above-described overflow pipe, the control unit 13 controls the water level sensor 12 so that the water level in the cooling water tank 2 is abnormal when the supply water valve 11a is shut off. When an abnormal rise is detected, the abnormality indicator 13a is notified of the occurrence of an abnormality caused by the occurrence of a cross connection.

  Here, the abnormality indicator 13a visually notifies the occurrence of the abnormality, but is not limited to such a form. For example, the abnormality indicator 13a may be configured to acoustically notify the occurrence of the abnormality. Or it is good also as a form which notifies to the monitoring center that the abnormal change of the water level generate | occur | produced in the cooling water tank 2 of the fuel cell system 100 not only in the form which alert | reports generation | occurrence | production of abnormality abnormally.

  In the present embodiment, when the control unit 13 informs the abnormality indicator 13a of the occurrence of an abnormality due to the occurrence of the cross connection, the fuel cell system 100 is stopped to execute the fuel cell system 100. The operation of is forcibly stopped. Then, after the operation of the fuel cell system 100 is stopped, the control unit 13 does not continuously permit the operation of the fuel cell system 100 to shift from the stopped state to the operation start. Thus, in the present embodiment, the operation of the fuel cell system 100 is stopped until the cross connection generated in the heat exchanger 5 is eliminated.

  As described above, in the present embodiment, the control unit 13 receives the water level detection signal from the water level sensor 12 that cannot occur in the normal state, determines an abnormal change in the water level in the cooling water tank 2, and notifies that abnormality. Visual notification is given by the display 13a. Such a characteristic operation according to the present embodiment is executed based on a control program stored in advance in a storage unit (not shown) included in the control unit 13 of the fuel cell system 100. Here, when the control unit 13 shuts off the supply water valve 11a and the discharge water valve 11b, the control unit 13 outputs a control signal indicating that the coolant is not supplied and discharged.

  The present embodiment exemplifies a mode in which when the occurrence of an abnormality due to the occurrence of cross connection is detected, the stop process of the fuel cell system 100 is executed and the transition to the operation start is not permitted continuously. However, it is not limited to such a form. For example, even when the occurrence of an abnormality due to the occurrence of a cross connection is detected while the power generation operation of the fuel cell system 100 is stopped, the control unit 13 shifts the operation of the fuel cell system 100 from the stop state to the operation start. Do not continue to allow. In this manner, regardless of the operation state of the fuel cell system 100, when the occurrence of an abnormality due to the occurrence of a cross connection is detected, the operation of the fuel cell system 100 is not permitted to shift to the operation start. This prevents the abnormal operation state of the fuel cell system 100 from continuing.

  As described above, according to the configuration of the fuel cell system 100 according to the present embodiment, when a cross connection occurs in the heat exchanger 5 and an abnormal water level rise occurs in the cooling water tank 2, the abnormal water level Since the water level sensor 12 detects the rise, the control unit 13 can notify the abnormality indicator 13a that a cross connection has occurred in the heat exchanger 5. As a result, it is possible to detect the occurrence of a cross connection in the heat exchanger 5, and thus it is possible to provide the fuel cell system 100 that can prevent the abnormal operation state from continuing.

  Moreover, in the fuel cell system that supplies a part of the cooling water to the hydrogen generator as water for generating fuel gas to be supplied to the fuel cell, the hot water (city water) contains a chlorine component. If the hot water containing the chlorine component is continuously mixed in the cooling water, the catalyst of the hydrogen generator deteriorates with time, and the power generation performance of the fuel cell system deteriorates with time. However, according to the configuration of the fuel cell system 100 according to the present embodiment, it is possible to detect the occurrence of a cross connection in the heat exchanger 5 and prevent the abnormal operation state from continuing, so that the fuel cell It is possible to minimize degradation of the power generation performance of the system 100.

  In addition, in a fuel cell system that supplies a portion of cooling water to the humidifier as fuel gas or air humidifying water supplied to the fuel cell, chlorine component is contained in the fuel gas or air by the chlorine component contained in the hot water. When mixed, the electrode catalyst of the fuel cell deteriorates with time, and the power generation performance of the fuel cell system deteriorates with time. However, according to the configuration of the fuel cell system 100 according to the present embodiment, it is possible to avoid such problems related to the deterioration of the electrode catalyst of the fuel cell 1.

(Embodiment 2)
First, the configuration of the fuel cell system according to Embodiment 2 of the present invention will be described.

  FIG. 2 is a block diagram schematically showing the configuration of the fuel cell system according to Embodiment 2 of the present invention. In FIG. 2, only components necessary for explaining the present invention are extracted and shown, and other components are not shown.

  As shown in FIG. 2, the fuel cell system 200 according to the present embodiment includes a fuel cell 1 that generates power using a hydrogen-rich fuel gas and an oxygen-containing oxidant gas, and a power generation operation of the fuel cell 1. A cooling water tank 2 for storing the cooling water for recovering the heat generated at the time and controlling the temperature of the fuel cell 1, and for circulating the cooling water between the cooling water tank 2 and the fuel cell 1. The cooling water flow path 3, the cooling water circulation pump 4 for passing cooling water through the cooling water flow path 3, and the heat for cooling the cooling water supplied by the cooling water circulation pump 4 and heated in the fuel cell 1 And an exchanger 5.

  In addition, the fuel cell system 200 is supplied with city water and stores it as hot water storage inside, and also supplies hot water storage water whose temperature has increased by recovering heat generated during the power generation operation of the fuel cell 1. A hot water storage tank 6 for supplying to a use device, and a hot water storage flow path 7 for passing hot water for cooling water cooling by heat exchange between the hot water storage tank 6 and the heat exchanger 5; The hot water storage channel 7 is provided with a hot water circulating pump 8 for circulating hot water stored in the hot water storage tank 6. Here, a city water shut-off valve 40 for shutting off the supply of city water is provided at a predetermined position in the city water side pipe connected to the hot water storage tank 6.

  The fuel cell system 200 includes a water level sensor 9 for detecting the water level in the cooling water tank 2, a water level sensor 15 for detecting a water level lower than the water level that can be detected by the water level sensor 9, and a cooling water tank. 2, a replenishing water tank 10 for storing cooling water to be replenished, a replenishing water pump 14 for replenishing and stopping cooling water from the replenishing water tank 10 to the cooling water tank 2, and a cooling water tank 2. Is provided with a cooling water discharge valve 16 for discharging the cooling water stored therein.

  On the other hand, as shown in FIG. 2, the fuel cell system 200 according to the present embodiment includes a hydrocarbon-based source gas (for example, city gas) as a supply source of hydrogen-rich fuel gas supplied to the fuel cell 1. ) For steam reforming, a burner 18 for burning part of the raw material gas or the generated fuel gas to maintain the temperature of the hydrogen generator 17, and the fuel generated in the hydrogen generator 17 A fuel gas supply channel 19 for supplying gas to the fuel cell 1 is provided.

  Further, as shown in FIG. 2, the fuel cell system 200 condenses the water vapor in the residual fuel gas discharged from the fuel cell 1 by heat exchange with the hot water stored in the hot water flow path 7 as moisture. A condenser 20 for separation, a residual fuel gas discharge passage 21 for supplying the residual fuel gas discharged from the fuel cell 1 through the condenser 20 to the burner 18, and the residual fuel gas discharge passage A condenser for condensing the water vapor in the combustion exhaust gas discharged from the burner 18 by the heat exchange with the hot water flowing through the hot water flow path 7 and separating it as moisture by burning the residual fuel gas supplied from the burner 18 22, a combustion exhaust gas discharge passage 23 for discharging the combustion exhaust gas discharged from the burner 18 through the condenser 22 from the exhaust port to the outside of the fuel cell system 200, and the fuel cell 1. A condenser 24 for condensing the water vapor in the residual oxidant gas (residual air) discharged from the water by heat exchange with the hot water flowing through the hot water passage 7 and separating it as moisture, A residual oxidant gas discharge passage 25 for discharging the residual oxidant gas discharged from the fuel cell 1 through the exhaust port to the outside of the fuel cell system 200;

  Here, as shown in FIG. 2, the fuel cell system 200 includes condensed water tanks 26, 27, 28 for storing condensed water discharged from the condensers 20, 22, 24, and the stored condensed water. Condensate water discharge valves 29, 30, 31 for discharging and water level sensors 32, 33, 34 for detecting the water levels of the condensed water tanks 26, 27, 28 are provided, and these water level sensors 32, Water level sensors 35, 36, and 37 are further provided for detecting water levels lower than those that can be detected by 33 and 34, respectively.

  As shown in FIG. 2, the fuel cell system 200 uses the water level sensors 9, 15, 32, 35, 33, 36, 34, 37 to control the water levels in the cooling water tank 2 and the condensed water tanks 26, 27, 28. While monitoring, based on the water level which the water level sensor 9,32,33,34 detects, the supplementary water pump 14 and the condensed water discharge valves 29,30,31 are operated, and the cooling water tank 2, the condensed water tanks 26,27,28 And a remote control 39 as an interface between the fuel cell system 200 including the control unit 38 and a user. Here, the remote control 39 includes an abnormality indicator 39a.

  Further, in the same manner as the configuration of the fuel cell system 100 according to the first embodiment, also in this fuel cell system 200, the fuel cell 1, the cooling water tank 2, the cooling water circulation pump 4, and the heat exchanger 5 are connected by the cooling water channel 3. It is connected in a ring. On the other hand, in the fuel cell system 200, the heat exchanger 5, the hot water storage tank 6, the hot water storage water circulation pump 8, and the condensers 20, 22, and 24 are connected in a ring shape by the hot water storage channel 7. Further, the makeup water pump 14, the cooling water discharge valve 16, the condensed water discharge valves 29, 30, and 31, the city water shutoff valve 40, the water level sensors 9 and 15, and the water level sensors 32 to 37 are electrically connected to the control unit 38 by wiring. It is connected.

  In the fuel cell system 200 according to the present embodiment, the heat exchanger 5 heats between the hot water stored in the hot water storage tank 6 and the cooling water as a medium for exhaust heat related to the power generation of the fuel cell 1. It is an example of specific embodiment of the heat exchanger made to exchange.

  The cooling water tank 2 is a specific embodiment of a water tank for storing cooling water as a medium for exhaust heat after exchanging heat with the hot water stored in the hot water storage tank 6 in the heat exchanger 5. It is an example. Further, the makeup water pump 14 and the cooling water discharge valve 16 are specific water level changers for changing the water level in the cooling water tank 2 by supplying water to the cooling water tank 2 and discharging water from the cooling water tank 2. It is an example of typical embodiment. Further, the control unit 38 controls the operation of the makeup water pump 14 and the cooling water discharge valve 16 based on the output signals of the water level sensor 9 and the water level sensor 15 to control the water level of the cooling water in the cooling water tank 2. It is an example of specific embodiment of a vessel.

  On the other hand, in the present embodiment, the condenser 20 is a heat exchanger that exchanges heat between the hot water stored in the hot water storage tank 6 and the residual fuel gas as a waste heat medium fluid related to power generation of the fuel cell 1. It is another example of specific embodiment. The condensate tank 26 is a water tank for storing condensate obtained from the residual fuel gas as a medium for exhaust heat after exchanging heat with the hot water stored in the hot water storage tank 6 in the condenser 20. It is another example of specific embodiment. On the other hand, the condensed water discharge valve 29 is another example of a specific embodiment of the water level changer for changing the water level of the condensed water in the condensed water tank 26 by discharging water from the condensed water tank 26. The control unit 38 is an example of a water level controller that controls the operation of the condensed water discharge valve 29 based on the detection signal of the water level sensor 32 to control the water level in the condensed water tank 26.

  Similarly, in the present embodiment, the condenser 22 is a heat exchanger that exchanges heat between the hot water stored in the hot water storage tank 6 and the combustion exhaust gas as a waste heat medium fluid related to power generation of the fuel cell 1. It is another example of specific embodiment of. The condensed water tank 27 is a specific example of a water tank for storing condensed water obtained from combustion exhaust gas as a medium for exhaust heat after exchanging heat with the hot water stored in the hot water storage tank 6 in the condenser 22. It is another example of typical embodiment. The condensed water discharge valve 30 is another example of a specific embodiment of a water level changer for changing the level of condensed water in the condensed water tank 27 by discharging water from the condensed water tank 27. The control unit 38 is an example of a water level controller that controls the operation of the condensed water discharge valve 30 based on the detection signal of the water level sensor 33 to control the water level in the condensed water tank 27.

  Similarly, in the present embodiment, the condenser 24 exchanges heat between the hot water stored in the hot water storage tank 6 and the residual oxidant gas as a waste heat medium fluid related to the power generation of the fuel cell 1. It is another example of specific embodiment of the heat exchanger to be made. The condensate tank 28 is a water tank for storing condensate obtained from the residual oxidant gas as a medium for exhaust heat after exchanging heat with the hot water stored in the hot water storage tank 6 in the condenser 24. It is another example of specific embodiment of. The condensed water discharge valve 31 is another example of a specific embodiment of a water level changer for changing the level of condensed water in the condensed water tank 28. The control unit 38 is an example of a water level controller that controls the operation of the condensed water discharge valve 31 based on the detection signal of the water level sensor 34 to control the water level in the condensed water tank 28.

  In the present embodiment, the water level sensor 15 and the cooling water discharge valve 16 are an example of a specific embodiment of a cooling water draining mechanism in the fuel cell system 200. Further, the water level sensor 35 and the condensed water discharge valve 29, the water level sensor 36 and the condensed water discharge valve 30, the water level sensor 37 and the condensed water discharge valve 31, respectively, are concrete implementations of the drainage mechanism of the condensed water in the fuel cell system 200. It is another example of the form. That is, in the fuel cell system 200 according to the present embodiment, the cooling water discharge valve 16, the condensed water discharge valve 29, the condensed water discharge valve 30, and the condensed water discharge valve 31 are the water level changer and the drainage mechanism of the fuel cell system 200. It also serves as.

  As described above, the remote control 39 according to the present embodiment includes the abnormality indicator 39a. This abnormality indicator 39a is an example of a specific embodiment of an abnormality notification device that notifies the occurrence of abnormality due to cross connection, as in the case of the first embodiment.

  Next, the basic operation of the fuel cell system 200 according to the present embodiment will be described.

  In the fuel cell system 200 according to the present embodiment, a hydrogen-rich fuel gas is generated by a steam reforming reaction using a hydrocarbon-based source gas such as city gas and water progressing in the hydrogen generator 17. The The fuel gas generated in the hydrogen generator 17 is supplied to the fuel cell 1 through the fuel gas supply channel 19. On the other hand, air as an oxidant gas is supplied to the fuel cell 1. Then, the fuel cell 1 generates electric power through an electrochemical reaction that uses a fuel gas containing hydrogen and air as an oxidant gas containing oxygen, and outputs direct current power. Here, the DC power output from the fuel cell 1 is converted into AC power by an inverter (not shown), and then supplied to a power load (not shown).

  At this time, a part of the fuel gas and the oxidant gas is discharged from the fuel cell 1 to the residual fuel gas discharge passage 21 and the residual oxidant gas discharge passage 25 as the residual fuel gas and the residual oxidant gas. . Here, the residual oxidant gas introduced into the condenser 24 via the residual oxidant gas discharge channel 25 is cooled by heat exchange with the hot water stored in the hot water channel 7, and the residual oxidant gas. The water vapor contained in is separated as condensed water. The separated condensed water is stored in the condensed water tank 28. The residual oxidant gas dehumidified and cooled by the condenser 24 is discharged to the outside of the fuel cell system 200 through the exhaust port. On the other hand, the residual fuel gas introduced into the condenser 20 through the residual fuel gas discharge passage 21 is cooled by heat exchange with the hot water flowing through the hot water passage 7 and the water vapor contained in the residual fuel gas. Is separated as condensed water. The separated condensed water is stored in the condensed water tank 26. Here, the residual fuel gas dehumidified by the condenser 20 is supplied to a burner 18 for maintaining the temperature state of the hydrogen generator 17 at a high temperature. Residual fuel gas burned in the burner 18 is discharged from the burner 18 to the combustion exhaust gas discharge passage 23 as combustion exhaust gas in a high temperature state. The combustion exhaust gas introduced into the condenser 22 via the combustion exhaust gas discharge passage 23 is cooled by heat exchange with the hot water stored in the hot water passage 7 and water vapor contained in the combustion exhaust gas is separated as condensed water. Is done. The separated condensed water is stored in the condensed water tank 27. The combustion exhaust gas dehumidified by the condenser 22 is discharged outside the fuel cell system 200 through the exhaust port.

  On the other hand, in the fuel cell 1, heat is generated simultaneously with the generation of DC power during the power generation operation. The heat generated in the fuel cell 1 is sequentially recovered by the cooling water by operating the cooling water circulation pump 4 and passing the cooling water circulating in the cooling water flow path 3 through the fuel cell 1 to exchange heat with the cooling water. The Thus, in the fuel cell system 200, the exhaust heat of the fuel cell 1 is sequentially recovered by the cooling water, so that the temperature of the fuel cell 1 is controlled to an appropriate temperature.

  Here, the cooling water whose temperature has been increased by heat exchange with the fuel cell 1 is then supplied to the heat exchanger 5 where it is cooled by heat exchange with the hot water flowing through the hot water flow path 7 and then cooled. Returned to the water tank 2. The cooling water returned to the cooling water tank 2 is again discharged from the cooling water tank 2 by the cooling water circulation pump 4 and supplied to the fuel cell 1 again. At this time, by operating the hot water circulating pump 8, the hot water stored in the hot water storage tank 6 is supplied to the hot water channel 7 and circulated in the hot water channel 7.

  The hot water supplied from the hot water storage tank 6 to the hot water flow path 7 is supplied to the condensers 20, 24 and 22 while passing through the hot water circulation pump 8 and then flowing through the hot water flow path 7. Then, the hot water is heated by heat exchange in the condensers 20, 24, and 22 and then supplied to the heat exchanger 5. Then, in the heat exchanger 5, the hot water is further heated by exchanging heat with the high-temperature cooling water supplied from the cooling water flow path 3. Then, the hot-water storage water whose temperature has been further increased passes through the hot-water storage channel 7 and is stored in the hot-water storage tank 6 as hot-water storage water in a high temperature state. Note that the stored hot water stored in a high temperature state is supplied from the upper side of FIG. 2 of the hot water storage tank 6 to a hot water supply utilization device (not shown) for hot water supply or hot water heating as required.

  On the other hand, during the power generation operation of the fuel cell system 200, when the water level sensor 9 detects a decrease in the water level in the cooling water tank 2 due to evaporation of the cooling water, the control unit 38 receives the detection signal and turns the makeup water pump 14 on. By operating, the cooling water stored in the makeup water tank 10 is supplied to the cooling water tank 2. Thereafter, when the water level sensor 9 detects the return of the water level in the cooling water tank 2 by replenishing the cooling water, the control unit 38 receives the detection signal and stops the operation of the replenishing water pump 14. The supply of cooling water to the cooling water tank 2 is stopped. At this time, if the water level sensors 32, 33, and 34 detect an increase in the water level in the condensed water tanks 26, 27, and 28 due to the condensate accumulation, the control unit 38 receives the detection signal and receives the condensed water discharge valve 29. , 30, 31 are operated to discharge excess condensed water stored in the condensed water tanks 26, 27, 28. Thereafter, when the water level sensors 32, 33, and 34 detect the return of the water level in the condensed water tanks 26, 27, and 28 due to the discharge of the condensed water, the control unit 38 receives the detection signal, and the condensed water discharge valves 29, 30, and 31 is shut off, thereby stopping the discharge of the condensed water from the condensed water tanks 26, 27, 28.

  Next, regarding the operation of the fuel cell system 200 according to the present embodiment, a characteristic operation for detecting the occurrence of cross connection in the heat exchanger 5 and a specific operation after detection will be described.

  FIG. 3 is a flowchart schematically showing a characteristic operation of the fuel cell system according to Embodiment 2 of the present invention. In the present embodiment, the water level sensors 9, 15, 32 to 37 of the fuel cell system 200 output an ON signal when the water level has reached the water level detection position, and when the water level has not reached. Outputs an OFF signal.

  First, the abnormality detection of the change in the water level in the cooling water tank 2 and the specific operation thereafter will be described. The control unit 38 is an operation for calculating the operation frequency of the makeup water pump 14 during the operation of the fuel cell system 200. After both the number counter N1 and the timer T1 are set to zero, the timer T1 is started (step S101).

  Next, the control unit 38 determines whether the operation state of the fuel cell 1 is operating or stopped (step S102). Here, when it is determined that the fuel cell 1 is in operation (YES in step S102), the control unit 38 determines whether or not the timer T1 has passed a predetermined time Tc (step S103). Then, when the predetermined time Tc has elapsed (YES in step S103), the control unit 38 indicates in advance that the operation number counter N1 of the makeup water pump 14 in the time equal to or longer than the predetermined time Tc is in the control unit 38. It is determined whether or not it is equal to or less than a predetermined number of operation times Nc (step S104). Specifically, in step S104, the control unit 38 detects that the water level in the cooling water tank 2 is equal to or lower than a predetermined lower limit value by the water level sensor 9, and the water level is set to a predetermined lower limit by the makeup water pump 12. It is determined whether or not the operation number counter N1 at a predetermined time when the cooling water tank 2 is replenished with cooling water so as to exceed the value is equal to or less than a predetermined operation number Nc set in advance. In other words, the control unit 38 detects that the water level in the cooling water tank 2 has become equal to or lower than the predetermined lower limit value by the water level sensor 9 and cools the water level by the make-up water pump 14 to exceed the predetermined lower limit value. It is determined whether or not the frequency of supplying the cooling water to the water tank 2 is equal to or lower than a predetermined supply frequency.

  In this fuel cell system 200, when the operation frequency counter N1 of the makeup water pump 14 is equal to or less than the predetermined operation frequency Nc (YES in step S104), the control unit 38 abnormally changes the water level in the cooling water tank 2. In the same manner as in the first embodiment, the operation of the fuel cell system 200 is stopped (step S115), and the next activation prohibition process of the fuel cell system 200 is performed (step S116). Next, the control unit 38 shuts off the city water shutoff valve 40 (step S117). Then, the control unit 38 of the fuel cell system 200 causes the abnormality indicator 39a of the remote control 39 to display "abnormality detection of water level change in the cooling water tank" or "prohibition of next activation".

  On the other hand, when the operation number counter N1 exceeds the predetermined operation number Nc in step S104 (NO in step S104), the control unit 38 indicates that the change in the water level in the cooling water tank 2 is a normal change in the water level. After determining and resetting both the operation number counter N1 and the timer T1 to zero, the timer T is started again (step S105).

  After execution of step S105 and when the timer T1 has not passed the predetermined time Tc (NO in step S103), the control unit 38 determines whether or not the water level sensor 9 outputs an OFF signal. (Step S106). Here, when the water level sensor 9 does not output the OFF signal but outputs the ON signal (NO in Step S106), the control unit 38 shifts the control step to Step S103.

  On the other hand, when the water level sensor 9 is outputting an OFF signal (YES in step S106), the control unit 38 operates the makeup water pump 14 (step S107). The control unit 38 monitors the output signal of the water level sensor 9 during operation of the makeup water pump 14 (step S108), and when the output of the water level sensor 9 is switched from the OFF signal to the ON signal (YES in step S108). Then, the operation of the makeup water pump 14 is stopped, and the operation number counter N1 is set to N1 = N1 + 1 (step S109). When the output of the water level sensor 9 does not switch from the OFF signal to the ON signal (NO in step S108), the control unit 38 shifts the control step to step S108.

  Thereafter, the control unit 38 determines whether the current operation state of the fuel cell 1 is operating or stopped (step S110). Here, when it is determined that the current operation state of the fuel cell 1 is in operation (NO in step S110), the control unit 38 shifts the control step to step S103. However, when determining that the current operation state of the fuel cell 1 is stopped (YES in Step S110), the control unit 38 operates the cooling water discharge valve 16 (Step S111). Thereby, the control part 38 discharges the cooling water stored in the cooling water tank 2.

  Next, the control unit 38 monitors the output signal of the water level sensor 15 during the operation of the cooling water discharge valve 16 (step S112), and detects that the output of the water level sensor 15 is switched from the ON signal to the OFF signal ( YES in step S112), the cooling water discharge valve 16 is shut off (step S113). Thereby, the control unit 38 stops the discharge of the cooling water stored in the cooling water tank 2. In addition, when the control part 38 detects that the output signal of the water level sensor 15 is an ON signal (it is NO at step S112), it transfers a control step to step S112 again.

  Thereafter, the control unit 38 monitors the output signal of the water level sensor 9 (step S114), and detects that the output of the water level sensor 9 has switched from the OFF signal to the ON signal (YES in step S114), the cooling water tank. The abnormal change of the water level at 2 is detected, the next activation prohibition process of the fuel cell system 200 is performed (step S116), and the city water shutoff valve 40 is shut off (step S117). At this time, the control unit 38 of the fuel cell system 200 causes the abnormality indicator 39a of the remote controller 39 to display “abnormality detection of change in water level in the cooling water tank” or “prohibition of next activation”. The control unit 38 detects an OFF signal from the water level sensor 9 in step S114 (NO in step S114), and determines that the fuel cell 1 is stopped in step S102, which is the transition destination ( In step 102, NO), step S102 and step S114 are repeated in that period, and monitoring of the output signal of the water level sensor 9 (step S114) is continued.

  As described above, according to the configuration of the fuel cell system 200 according to the present embodiment, when a cross connection occurs in the heat exchanger 5, the operating frequency (N1 / Tc) of the makeup water pump 14 is higher than the operating frequency during normal operation. Although the water level in the cooling water tank 2 can be kept constant with a low operation frequency, a predetermined replenishment frequency in which the operation frequency of the make-up water pump 14 is preset in the control unit 38 using this characteristic phenomenon. If it is detected that it is less than (Nc / Tc), the control unit 38 can notify that a cross connection has occurred in the heat exchanger 5.

  Further, according to the present embodiment, when the control unit 38 stops the operation of the makeup water pump 14, the cooling water discharge valve 16 is operated and the water level sensor 15 outputs an OFF signal to the water level in the cooling water tank 2. When the cross-connection occurs in the heat exchanger 5, the water level sensor 9 rises to a level at which the water level sensor 9 outputs an ON signal, so that the control unit 38 is turned on from the water level sensor 9. By detecting the signal, it is possible to notify that a cross connection has occurred in the heat exchanger 5.

  Further, according to the present embodiment, when a cross connection occurs in the heat exchanger 5 and the control unit 38 informs the abnormality indicator 39a of the occurrence of abnormality, the stop process is executed, and the fuel cell system 100 Therefore, the leakage of electricity in the fuel cell 1 continues, and the hot water supplied from the hot water storage tank 6 to the cooling water tank 2 via the heat exchanger 5 is continuously discarded. Can be prevented. In this case, the control unit 38 does not continuously permit the operation start of the fuel cell system 100 from the stopped state, thereby preventing the fuel cell system 200 from being erroneously restarted in a state where the cross connection has occurred. It becomes possible to do.

  Further, according to the present embodiment, when a cross connection occurs in the heat exchanger 5, the abnormality indicator 39a of the remote control 39 displays "abnormality detection of change in water level in the cooling water tank" or "prohibition of next activation". ”Is displayed, the user can visually recognize that a cross connection has occurred in the heat exchanger 5.

  Further, according to the present embodiment, when the cross connection occurs in the heat exchanger 5, the city water shutoff valve 40 is shut off by the control unit 38, so that the city water supply source to the hot water storage tank 6 is shut off. New inflow of city water is prevented. This prevents city water from mixing into the cooling water flow path 3 and the cooling water tank 2, thereby preventing leakage in the fuel cell 1.

  In the operation of the fuel cell system 200 according to the present embodiment, the control unit 38 controls the water level in the cooling water tank 2 by controlling the cooling water discharge valve 16 based on the output signal of the water level sensor 15. However, it is not limited to such a form. For example, the control unit 38 may control the water level in the cooling water tank 2 by operating the cooling water discharge valve 16 for a predetermined time without using the water level sensor 15. For example, in steps S111 to S113 shown in FIG. 3, the cooling water discharge valve 16 is stopped based on the output signal of the water level sensor 15. However, the water level in the cooling water tank 2 is controlled to a prescribed water level in advance by steps S107 to S109. Therefore, the control unit 38 can lower the water level in the cooling water tank 2 to a desired water level by operating the cooling water discharge valve 16 for a predetermined time.

  Further, in the fuel cell system 200 according to the present embodiment, a water level sensor 15 is provided. However, if there is a reference in the ON signal / OFF signal output by the water level sensor 9, the cooling water discharge valve 16 may be operated until the OFF signal from the water level sensor 9 is detected without providing the water level sensor 15. Good.

  In the fuel cell system 200 according to the present embodiment, the replenishing water pump 14 for supplying the cooling water stored in the replenishing water tank 10 to the cooling water tank 2 is provided. However, the present invention is not limited to this. Absent. For example, instead of the form in which the make-up water pump 14 is provided, a form in which a make-up water valve (for example, the make-up water valve 11a shown in FIG. 1) may be provided.

  In the present embodiment, the fuel cell system 200 includes the condensate discharge valves 29 and 31. However, the present invention is not limited to such a form. For example, as in the case of the fuel cell system 100 shown in Embodiment 1, the condensed water tanks 26 and 28 may each have an overflow pipe.

  Other points are the same as those in the first embodiment.

(Embodiment 3)
The configuration and basic operation of the fuel cell system according to Embodiment 3 of the present invention are the same as the configuration and basic operation of the fuel cell system according to Embodiment 2 shown in FIG. Therefore, a description of the configuration and basic operation of the fuel cell system according to Embodiment 3 of the present invention is omitted.

  Hereinafter, regarding the operation of the fuel cell system according to the present embodiment, a characteristic operation for detecting the occurrence of cross connection in the condenser 20 of the fuel cell system 200 shown in FIG. Will be described.

  FIG. 4 is a flowchart schematically showing a characteristic operation of the fuel cell system according to Embodiment 3 of the present invention. In the present embodiment, the water level sensors 32 and 35 of the fuel cell system 200 output an ON signal when the water level reaches the water level detection position, and output an OFF signal when the water level has not reached. Output.

  First, the control unit 38 sets both the operation number counter N2 and the timer T2 for calculating the operation frequency of the condensed water discharge valve 29 during operation of the fuel cell system 200 to zero, and then starts the timer T2 ( Step S201).

  Next, the control unit 38 determines whether the operation state of the fuel cell 1 is operating or stopped (step S202). If it is determined that the fuel cell 1 is in operation (YES in step S202), the control unit 38 determines whether or not the timer T2 has passed a predetermined time Tc (step S203). When the predetermined time Tc has elapsed (YES in step S203), the control unit 38 sets the operation number counter N2 of the condensed water discharge valve 29 to the control unit 38 within the predetermined time Tc. It is determined whether or not the predetermined number of operation times Nc is set in advance (step S204). Specifically, in step S204, the control unit 38 detects that the water level in the condensed water tank 26 is equal to or higher than a predetermined upper limit value by the water level sensor 32, and sets the water level to a predetermined upper limit by the condensed water discharge valve 29. It is determined whether or not the operation number counter N2 at a predetermined time Tc controlled to be less than the value is equal to or greater than a predetermined operation number Nc set in advance. In other words, the control unit 38 detects that the water level in the condensed water tank 26 is equal to or higher than the predetermined upper limit value by the water level sensor 32, and causes the condensed water discharge valve 29 to reduce the water level below the predetermined upper limit value. It is determined whether or not the operation number counter N2 at a predetermined time when the condensed water is discharged from the tank 26 is equal to or greater than a predetermined operation number Nc set in advance.

  When the operation number counter N2 of the condensed water discharge valve 29 is equal to or greater than the predetermined operation number Nc (YES in step S204), the control unit 38 detects an abnormal change in the water level in the condensed water tank 26, and implements it. As in the first and second embodiments, the operation of the fuel cell system 200 is stopped (step S215), and the next activation prohibition process of the fuel cell system 200 is performed (step S216). Next, the control unit 38 shuts off the city water shut-off valve 40 (step S217). Then, the control unit 38 of the fuel cell system 200 causes the abnormality indicator 39a of the remote control 39 to display "abnormality detection of water level change in the cooling water tank" or "prohibition of next activation".

  On the other hand, when the operation number counter N2 is less than the predetermined operation number Nc in step S204 (NO in step S204), the control unit 38 resets both the operation number counter N2 and the timer T2 to zero, T2 is started again (step S205).

  After execution of step S205 and when the timer T2 has not passed the predetermined time Tc (NO in step S203), the control unit 38 determines whether or not the water level sensor 32 outputs an ON signal. (Step S206). Here, when the water level sensor 32 does not output the ON signal but outputs the OFF signal (NO in Step S206), the control unit 38 shifts the control step to Step S203.

  On the other hand, when the water level sensor 32 is outputting the ON signal (YES in step S206), the control unit 38 operates the condensed water discharge valve 29 (step S207). Then, the control unit 38 monitors the output signal of the water level sensor 32 during the operation of the condensed water discharge valve 29 (step S208), and when the output of the water level sensor 32 switches from the ON signal to the OFF signal (YES in step S208). ) The operation of the condensed water discharge valve 29 is stopped, and the operation number counter N2 is set to N2 = N2 + 1 (step S209). If the output of the water level sensor 32 does not switch from the ON signal to the OFF signal (NO in step S208), the control unit 38 shifts the control step to step S208.

  Thereafter, the control unit 38 determines whether the current operation state of the fuel cell 1 is operating or stopped (step S210). Here, when the current operation state of the fuel cell 1 is in operation (NO in step S210), the control unit 38 shifts the control step to step S203. However, when determining that the current operation state of the fuel cell 1 is stopped (YES in step S210), the control unit 38 operates the condensed water discharge valve 29 (step S211). Thereby, the control unit 38 discharges the condensed water stored in the condensed water tank 26.

  Next, the control unit 38 monitors the output signal of the water level sensor 35 during the operation of the cooling water discharge valve 29 (step S212), and detects that the output signal of the water level sensor 35 has switched from the ON signal to the OFF signal. (YES in step S212), the condensed water discharge valve 29 is shut off (step S213). Thereby, the control part 38 stops discharge | emission of the condensed water stored in the condensed water tank 26. FIG. In addition, if the control part 38 detects that the output signal of the water level sensor 15 is an ON signal (it is NO at step S212), it will transfer a control step to step S212 again.

  And the control part 38 monitors the output signal of the water level sensor 32 (step S214), and if it detects that the output of the water level sensor 32 switched from the OFF signal to the ON signal (YES in step S214), the condensed water tank. The abnormal change of the water level at 26 is detected, the next activation prohibition process of the fuel cell system 200 is performed (step S216), and the city water shutoff valve 40 is shut off (step S217). At this time, the control unit 38 of the fuel cell system 200 causes the abnormality indicator 39a of the remote controller 39 to display “abnormality detection of change in water level in the condensed water tank” or “prohibition of next activation”. The control unit 38 detects an OFF signal from the water level sensor 32 in step S214 (NO in step S214), and determines that the fuel cell 1 is stopped in step S202, which is the transition destination (step 202). NO), step S202 and step S214 are repeated in that period, and the monitoring of the output signal of the water level sensor 32 (step S214) is continued.

  As described above, according to the characteristic operation according to the present embodiment, when a cross connection occurs in the condenser 20, the operation frequency (N2 / Tc) of the condensed water discharge valve 29 is higher than the normal operation frequency. Although the water level in the condensate tank 26 can be kept constant at a frequency, this characteristic phenomenon is used to make the operating frequency of the condensate drain valve 29 a predetermined replenishment frequency preset in the control unit 38 ( If it is detected that it is equal to or greater than (Nc / Tc), the control unit 38 can notify that the cross connection has occurred in the condenser 20.

  Further, according to the present embodiment, when the control unit 38 stops the operation of the fuel cell 1, the condensate drain valve 29 is operated, and the water level sensor 35 outputs the OFF signal to the water level in the condensate water tank 26. By setting the water level, when the cross connection occurs in the condenser 20, the water level rises to a water level at which the water level sensor 32 outputs an ON signal, so the control unit 38 detects the ON signal from the water level sensor 32. By doing so, it is possible to notify that a cross connection has occurred in the condenser 20.

  Further, according to the present embodiment, when a cross connection occurs in the condenser 20 and the control unit 38 informs the abnormality indicator 39a of the occurrence of an abnormality, the stop process is executed, and the fuel cell system 200 Since it is not allowed to forcibly stop the operation and thereafter continue to start the operation from the stopped state, it is possible to prevent the fuel cell 1 from continuing the electric leakage or accidentally restarting the fuel cell system 200. Is possible.

  Further, according to the present embodiment, when a cross connection occurs in the condenser 20, the abnormality indicator 39a of the remote control 39 displays "abnormality detection of change in water level in the condensed water tank" or "prohibition of next activation". Is displayed, the user can visually recognize that a cross connection has occurred in the condenser 20.

  Furthermore, according to the present embodiment, when the cross connection occurs in the condenser 20, the city water shutoff valve 40 is shut off by the control unit 38, so that the city water from the city water supply source to the hot water storage tank 6 can be used. New inflow of water is prevented. Thereby, it is possible to prevent leakage in the fuel cell 1.

  Here, in this embodiment, the characteristic operation when the cross connection occurs in the condenser 20 has been described. However, the water level sensors 33, 34, and 36 are replaced with the water level sensors 32 and 35 and the condensed water discharge valve 29. , 37 and the condensed water discharge valves 30 and 31, it is possible to notify the occurrence of cross connection in the condensed water tanks 27 and 28 as in the case of the condensed water tank 26. That is, based on the characteristic operation according to the present embodiment, it is possible to notify the occurrence of cross connection in all of the condensers 20, 22, and 24 of the fuel cell system 200.

  In the fuel cell system 200 according to the present embodiment, the condensed water tanks 26, 27, and 28 are provided independently. However, the present invention is not limited to this configuration, and the condensers 20, 22, and 24 are provided. It is good also as a form which stores the condensed water discharged | emitted from one in one condensed water tank. In this case, the occurrence of a cross connection in any one of the condensers 20, 22, and 24 is detected based on an abnormal change in the water level in that one condensed water tank in the same manner as the characteristic operation according to the present embodiment. Is possible.

  In this connection, in the fuel cell system 200, the condensed water discharged from two of the condensed water tanks 26, 27, and 28 (for example, the condensed water tanks 26 and 27) is transferred to the other condensed water tanks ( For example, supply to the condensate water tank 28) and notification of the occurrence of cross-connection in any of the condensers 20, 22, 24 based on an abnormal change in the water level in other condensate water tanks (for example, the condensate water tank 28). It is good also as a form to do. Even with this configuration, it is possible to obtain the same effect as that obtained by the present embodiment.

  On the other hand, in the operation of the fuel cell system 200 according to the present embodiment, the control unit 38 controls the condensed water discharge valves 29, 30, 31 based on the output signals of the water level sensors 35, 36, 37, thereby causing the condensed water tank 26. , 27 and 28 are illustrated as examples of controlling the water level, but the present invention is not limited to such a form. For example, the controller 38 controls the water levels in the condensed water tanks 26, 27, 28 by operating the condensed water discharge valves 29, 30, 31 for a predetermined time without using the water level sensors 35, 36, 37. It is good also as a form. For example, in steps S <b> 211 to S <b> 213 shown in FIG. 4, the condensed water discharge valve 29 is stopped based on the output signal of the water level sensor 35. However, the water level in the condensed water tank 26 is controlled to a prescribed water level in advance by steps S207 to S209. Therefore, the control unit 38 can lower the water level in the condensed water tank 26 to a desired water level by operating the condensed water discharge valve 29 for a predetermined time.

  In the fuel cell system 200 according to the present embodiment, water level sensors 35, 36, and 37 are provided. However, when there is a reference in the ON signal / OFF signal output from the water level sensors 32, 33, 34, the OFF signals from the water level sensors 32, 33, 34 are detected without providing the water level sensors 35, 36, 37. Until this time, the condensed water discharge valves 29, 30, 31 may be operated.

  The fuel cell system 200 according to the present embodiment is configured such that the hot water discharged from the hot water storage tank 6 passes through the condensers 20, 24, 22 and the heat exchanger 5 in this order. It is not limited to such a configuration. The arrangement order of the condensers 20, 24, 22 and the heat exchanger 5 is any arrangement order as long as the heat exchange between the hot water and the cooling water, the fuel gas, the oxidant gas, and the like is preferably possible. Also good. Moreover, in this Embodiment, although the condenser 20, 24, 22 and the heat exchanger 5 have illustrated the form arrange | positioned in series, it is not limited to such a form and arrange | positions in parallel suitably. It is good also as a form to do.

(Embodiment 4)
FIG. 5 is a block diagram schematically showing the configuration of the fuel cell system according to Embodiment 4 of the present invention. In FIG. 5, only components necessary for explaining the present invention are extracted and illustrated, and other components are not illustrated. In FIG. 5, the same components as those of the fuel cell system 200 shown in FIG. 2 are denoted by the same reference numerals, and description of those components is omitted in the following description.

  As shown in FIG. 5, the configuration of fuel cell system 300 according to Embodiment 4 of the present invention is basically the same as the configuration of fuel cell system 200 according to Embodiments 2 and 3 shown in FIG. is there. However, the configuration of the fuel cell system 300 according to Embodiment 4 of the present invention is different from the configuration of the fuel cell system 200 shown in FIG. 2 in the following three points.

  First, the first difference will be described. The configuration of the fuel cell system 300 according to the present embodiment is that the water level sensors 9 and 32 for detecting the water level in the cooling water tank 2 and the condensed water tanks 26, 27, and 28. 2, 33 and 34 are different from the configuration of the fuel cell system 200 shown in FIG. 2 in that the water level sensors 12, 41, 42 and 43 for detecting a higher water level than the detectable water level are further provided. Yes. Here, the water level sensors 12, 41, 42, 43 are electrically connected to the control unit 38 by wiring in the same manner as the water level sensors 9, 15, 32-34, 35-37.

  Next, the second difference will be described. The configuration of the fuel cell system 300 according to the present embodiment is to replace the city water shut-off valve 40 and shut off the supply of hot water stored in a hot water supply device to the hot water supply equipment. 2 is different from the configuration of the fuel cell system 200 shown in FIG. Here, the hot water shutoff valve 44 is electrically connected to the control unit 38 by wiring in the same manner as the city water shutoff valve 40.

  Further, the third difference will be described. The configuration of the fuel cell system 300 according to the present embodiment indicates that an abnormality caused by the occurrence of a cross connection has occurred in place of the abnormality indicator 39a shown in FIG. The fuel cell system 200 is different from the configuration of the fuel cell system 200 shown in FIG. 2 in that an alarm device 45 for notifying by voice or alarm sound is provided. The alarm device 45 is an example of a specific embodiment of an abnormality alarm device for notifying the occurrence of an abnormality caused by cross connection.

  In addition, about the other point, the structure of the fuel cell system 200 which concerns on Embodiment 2, 3 and the structure of the fuel cell system 300 which concerns on this Embodiment are the same.

  The basic operation of the fuel cell system 300 according to the present embodiment is the same as the basic operation of the fuel cell system 200 according to the second and third embodiments.

  Hereinafter, with respect to the operation of the fuel cell system 300 according to the present embodiment, a characteristic operation for detecting the occurrence of cross connection in the heat exchanger 5 of the fuel cell system 300 shown in FIG. The operation will be described.

  FIG. 6 is a flowchart schematically showing a characteristic operation of the fuel cell system according to Embodiment 4 of the present invention. Also in the present embodiment, the water level sensors 9, 12, and 15 of the fuel cell system 300 output an ON signal when the water level reaches the water level detection position, and when the water level does not reach the water level detection position. Outputs an OFF signal.

  As shown in FIG. 6, first, the control unit 38 of the fuel cell system 300 determines whether the current operation state of the fuel cell 1 is in operation or is stopped (step S301). If it is determined in step S301 that the operation state of the fuel cell 1 is in operation (YES in step S301), the control unit 38 determines whether the output signal of the water level sensor 12 is an ON signal or an OFF signal. (Step S302).

  If the control unit 38 determines that the output signal of the water level sensor 12 is an ON signal (YES in step S302), the control unit 38 detects an abnormal change in the water level in the cooling water tank 2 and operates the fuel cell system 300. Is stopped (step S312), and the next activation prohibition process of the fuel cell system 300 is performed (step S313). Further, the control unit 38 shuts off the hot water shutoff valve 44 (step S314). Then, the control unit 38 of the fuel cell system 300 notifies the alarm device 45 of “abnormality detection of change in water level in the cooling water tank” or “prohibition of next activation” by voice or alarm sound.

  On the other hand, when the control unit 38 determines that the output signal of the water level sensor 12 is an OFF signal (NO in step S302), the control unit 38 determines that the water level in the cooling water tank 2 is a normal water level, and outputs the water level sensor 9. It is determined whether the signal is an ON signal or an OFF signal (step S303). Here, when the water level sensor 9 outputs the ON signal without outputting the OFF signal (NO in Step S303), the control unit 38 shifts the control step to Step S302.

  In contrast, when the water level sensor 9 outputs an OFF signal (YES in step S303), the control unit 38 operates the makeup water pump 14 (step S304). Then, the control unit 38 monitors the output signal of the water level sensor 9 during operation of the makeup water pump 14 (step S305), and when the output signal of the water level sensor 9 is switched from the OFF signal to the ON signal (YES in step S305). ), The operation of the makeup water pump 14 is stopped (step S306). When the output of the water level sensor 9 does not switch from the OFF signal to the ON signal (NO in step S305), the control unit 38 causes the control step to move again to step S305.

  Thereafter, the control unit 38 determines whether the current operation state of the fuel cell 1 is in operation or is stopped (step S307). Here, if the current operation state of the fuel cell 1 is in operation (NO in step S307), the control unit 38 shifts the control step to step S302. However, when the control unit 38 determines that the current operation state of the fuel cell 1 is stopped (YES in step S307), the control unit 38 operates the cooling water discharge valve 16 (step S308). Thereby, the control part 38 discharges the cooling water stored in the cooling water tank 2.

  Next, the control unit 38 monitors the output signal of the water level sensor 15 during the operation of the cooling water discharge valve 16 (step S309), and detects that the output signal of the water level sensor 15 has switched from the ON signal to the OFF signal. (YES in step S309), the cooling water discharge valve 16 is shut off (step S310). Thereby, the control unit 38 stops the discharge of the cooling water stored in the cooling water tank 2. In addition, if the control part 38 detects that the output signal of the water level sensor 15 is an ON signal (it is NO at step S309), it will transfer a control step to step S309 again.

  Thereafter, the control unit 38 monitors the output signal of the water level sensor 9 (step S311), and detects that the output signal of the water level sensor 9 has switched from the OFF signal to the ON signal (YES in step S311). When an abnormal change in the water level in the tank 2 is detected, the next activation prohibition process of the fuel cell system 300 is performed (step S313), and the hot water supply shutoff valve 44 is shut off (step S314). And the control part 38 alert | reports the effect of "abnormality detection of the change of the water level in a cooling water tank" or "prohibition of the next start" by the alarm device 45 with a sound or an alarm sound. The controller 38 detects an OFF signal from the water level sensor 9 in step S311 (NO in step S311), and determines that the fuel cell 1 is stopped in step S301, which is the transition destination (step 301). NO), step S301 and step S311 are repeated in that period, and monitoring of the output signal of the water level sensor 9 (step S311) is continued.

  As described above, according to the characteristic configuration of the fuel cell system 300 according to the present embodiment, when a cross connection occurs in the heat exchanger 5, the hot water stored in the hot water flow path 7 passes through the heat exchanger 5. The coolant level flows into the coolant channel 3 and the water level in the coolant tank 2 rises above the water level that can be detected by the water level sensor 9. However, the coolant tank 2 in a state in which coolant is not replenished from the makeup water tank 10. By detecting an ON signal from the water level sensor 12 that cannot occur at normal time, the control unit 38 detects an abnormal rise in the water level in the cooling water tank 2 and a cross connection has occurred in the heat exchanger 5. Can be notified by the alarm device 45.

  Further, in the present embodiment, when the control unit 38 stops the operation of the fuel cell 1, the cooling water discharge valve 16 is opened and the cooling water is discharged from the cooling water tank 2. And the control part 38 reduces the water level in the cooling water tank 2 to the water level which the water level sensor 15 outputs an OFF signal. Thereby, when a cross connection occurs in the heat exchanger 5 and the water level in the cooling water tank 2 rises to a water level at which an ON signal is output from the water level sensor 9, the control unit 38 outputs from the water level sensor 9. By detecting the generated ON signal, it is possible to detect an abnormal rise in the water level in the cooling water tank 2 and notify that a cross connection has occurred in the heat exchanger 5.

  Further, according to the configuration of the fuel cell system 300 according to the present embodiment, when a cross connection occurs in the heat exchanger 5 and the water level in the cooling water tank 2 rises abnormally, the control unit 38 detects the alarm 45. Will notify the user of the occurrence of a cross connection by voice or alarm sound to indicate “abnormality detection of water level change in cooling water tank” or “prohibition of next start”. become.

  Furthermore, according to the configuration of the fuel cell system 300 according to the present embodiment, when a cross connection occurs in the heat exchanger 5 and the water level in the cooling water tank 2 rises abnormally, the control unit 38 controls the hot water supply cutoff valve. 44, the hot water stored in the hot water storage tank 6 flows into the cooling water flow due to the head pressure even when hot water is used in a situation where the supply of city water to the hot water storage tank 6 is interrupted. It becomes possible to prevent inflow into the path 4.

  In the operation of the fuel cell system 300 according to the present embodiment, the control unit 38 controls the water level in the cooling water tank 2 by controlling the cooling water discharge valve 16 based on the output signal of the water level sensor 15. However, it is not limited to such a form. For example, the control unit 38 may control the water level in the cooling water tank 2 by operating the cooling water discharge valve 16 for a predetermined time without using the water level sensor 15. Specifically, in step S308 to step S310 shown in FIG. 6, the cooling water discharge valve 16 is activated and stopped based on the output signal of the water level sensor 15. However, the water level in the cooling water tank 2 is controlled to a predetermined water level in advance by steps S304 to S306. Therefore, the control unit 38 can lower the water level in the cooling water tank 2 to a desired water level by operating the cooling water discharge valve 16 for a predetermined time.

  In the fuel cell system 300 according to the present embodiment, the water level sensor 15 is provided. However, if there is a reference in the ON signal / OFF signal output by the water level sensor 9, the cooling water discharge valve 16 may be operated until the OFF signal from the water level sensor 9 is detected without providing the water level sensor 15. Good.

  In the fuel cell system 300 according to the present embodiment, the replenishing water pump 14 for supplying the cooling water stored in the replenishing water tank 10 to the cooling water tank 2 is provided. However, the present invention is not limited to this. Absent. For example, instead of the form in which the make-up water pump 14 is provided, a form in which a make-up water valve (for example, the make-up water valve 11a shown in FIG. 1) may be provided.

(Embodiment 5)
The configuration and basic operation of the fuel cell system according to Embodiment 5 of the present invention are the same as the configuration and basic operation of the fuel cell system according to Embodiment 4 shown in FIG. Therefore, a description of the configuration and basic operation of the fuel cell system according to Embodiment 5 of the present invention is omitted.

  Hereinafter, regarding the operation of the fuel cell system according to the present embodiment, a characteristic operation for detecting the occurrence of cross connection in the condenser 20 of the fuel cell system 300 shown in FIG. Will be described.

  FIG. 7 is a flowchart schematically showing a characteristic operation of the fuel cell system according to Embodiment 5 of the present invention. In the present embodiment, the water level sensors 32, 35, 41 of the fuel cell system 300 output an ON signal when the water level reaches the water level detection position, and turn off when the water level has not reached. Output a signal.

  As shown in FIG. 7, first, the control unit 38 of the fuel cell system 300 determines whether the current operation state of the fuel cell 1 is operating or stopped (step S401). If it is determined in step S401 that the operation state of the fuel cell 1 is in operation (YES in step S401), the control unit 38 determines whether the output signal of the water level sensor 41 is an ON signal or an OFF signal. (Step S402).

  If the control unit 38 determines that the output signal of the water level sensor 41 is an ON signal (YES in step S402), the control unit 38 detects an abnormal change in the water level in the cooling water tank 2 and operates the fuel cell system 300. Is stopped (step S412), and the next activation prohibition process of the fuel cell system 300 is performed (step S413). Further, the control unit 38 shuts off the hot water shutoff valve 44 (step S414). Then, the control unit 38 of the fuel cell system 300 notifies the alarm device 45 of “abnormality detection of change in water level in the condensed water tank 26” or “prohibition of next activation” by voice or alarm sound.

  In contrast, if the control unit 38 determines that the output signal of the water level sensor 41 is an OFF signal (NO in step S402), the control unit 38 determines that the water level in the condensed water tank 26 is a normal water level, and then the water level sensor. It is determined whether the output signal 32 is an ON signal or an OFF signal (step S403). Here, when the water level sensor 32 outputs the ON signal without outputting the OFF signal (NO in Step S403), the control unit 38 shifts the control step to Step S402.

  On the other hand, when the water level sensor 32 outputs an OFF signal (YES in step S403), the control unit 38 operates the condensed water discharge valve 29 (step S404). Then, the control unit 38 monitors the output signal of the water level sensor 32 during the operation of the condensed water discharge valve 29 (step S405), and when the output signal of the water level sensor 32 is switched from the OFF signal to the ON signal (in step S405). YES), the operation of the condensed water discharge valve 29 is stopped (step S406). If the output of the water level sensor 32 does not switch from the OFF signal to the ON signal (NO in step S405), the control unit 38 shifts the control step to step S405 again.

  Thereafter, the control unit 38 determines whether the current operation state of the fuel cell 1 is in operation or is stopped (step S407). Here, if the current operation state of the fuel cell 1 is in operation (NO in step S407), the control unit 38 shifts the control step to step S402. However, if the control unit 38 determines that the current operation state of the fuel cell 1 is stopped (YES in step S407), the control unit 38 operates the condensed water discharge valve 29 (step S408). Thereby, the control unit 38 discharges the condensed water stored in the condensed water tank 26.

  Next, the control unit 38 monitors the output signal of the water level sensor 35 during the operation of the condensed water discharge valve 29 (step S409), and detects that the output signal of the water level sensor 35 has switched from the ON signal to the OFF signal. (YES in step S409), the condensed water discharge valve 29 is shut off (step S410). Thereby, the control part 38 stops discharge | emission of the condensed water stored in the condensed water tank 26. FIG. In addition, if the control part 38 detects that the output signal of the water level sensor 35 is an ON signal (it is NO at step S409), it will transfer a control step to step S409 again.

  Thereafter, the control unit 38 monitors the output signal of the water level sensor 32 (step S411), and detects that the output signal of the water level sensor 32 has been switched from the OFF signal to the ON signal (YES in step S411). When an abnormal change in the water level in the condensed water tank 26 is detected, the next activation prohibition process of the fuel cell system 300 is performed (step S413), and the hot water supply shutoff valve 44 is shut off (step S414). And the control part 38 alert | reports to the effect of "abnormality detection of the change of the water level in the condensed water tank 26" or "prohibition of the next start" by the alarm device 45 with an audio | voice or an alarm sound. The controller 38 detects an OFF signal from the water level sensor 32 in step S411 (NO in step S411), and determines that the fuel cell 1 is stopped in step S401, which is the transition destination (step 401). NO), step S401 and step S411 are repeated in that period, and monitoring of the output signal of the water level sensor 32 (step S411) is continued.

  As described above, according to the characteristic configuration of the fuel cell system 300 according to the present embodiment, when a cross connection occurs in the condenser 20, the hot water stored in the hot water flow path 7 is stored via the condenser 20. The water level flows into the water flow path 21 and the water level in the condensate water tank 26 rises above the water level that can be detected by the water level sensor 32, but the condensed water in a state where the condensed water is not replenished from the condenser 20 (fuel cell 1). By detecting an ON signal from the water level sensor 41 that cannot occur in the tank 26 at a normal time, the control unit 38 detects an abnormal rise in the water level in the condensed water tank 26 and a cross connection occurs in the condenser 20. This can be notified by an alarm device.

  Further, in the present embodiment, when the control unit 38 stops the operation of the fuel cell 1, the condensed water discharge valve 29 is opened and the condensed water is discharged from the condensed water tank 26. And the control part 38 reduces the water level in the condensed water tank 26 to the water level from which the water level sensor 35 outputs an OFF signal. Thereby, the control part 38 is output from the water level sensor 32, when the cross connection generate | occur | produces in the condenser 20 and the water level in the condensed water tank 26 rose to the water level from which the ON signal is output from the water level sensor 32. By detecting the ON signal, it is possible to detect an abnormal rise in the water level in the condensed water tank 26 and notify that a cross connection has occurred in the condenser 20. In addition, this makes it possible to prohibit the next activation of the fuel cell system 300.

  In addition, according to the configuration of the fuel cell system 300 according to the present embodiment, when a cross connection occurs in the condenser 20 and the water level in the condensed water tank 26 rises abnormally, the control unit 38 uses the alarm device 45. Since the notification of "abnormality detection of water level change in the condensed water tank 26" or "prohibition of next activation" is made by voice or alarm sound, it is possible to audibly notify the user of the occurrence of a cross connection. become.

  Furthermore, according to the configuration of the fuel cell system 300 according to the present embodiment, when a cross connection occurs in the condenser 20 and the water level in the condensed water tank 26 rises abnormally, the control unit 38 controls the hot water supply cutoff valve. 44, the hot water stored in the hot water storage tank 6 is condensed by the head pressure even when hot water is used in a situation where the supply of city water to the hot water storage tank 6 is interrupted. It becomes possible to prevent inflow into the tank 26.

  Here, in the present embodiment, the characteristic operation when the cross connection occurs in the condenser 20 has been described, but the water level sensors 33, 34 are replaced with the water level sensors 32, 35, 41 and the condensed water discharge valve 29. , 36, 37, 42, 43 and the condensed water discharge valves 30, 31, it is possible to notify the occurrence of cross connection in the condensed water tanks 27, 28 in the same manner as in the condensed water tank 26. Become. That is, based on the characteristic operation according to the present embodiment, it is possible to notify the occurrence of cross connection in all the condensers 20, 22, and 24 of the fuel cell system 300.

  In the fuel cell system 300 according to the present embodiment, the condensed water tanks 26, 27, and 28 are provided independently. However, the present invention is not limited to this configuration, and the condensers 20, 22, and 24 are provided. It is good also as a form which stores the condensed water discharged | emitted from one in one condensed water tank. In this case, the occurrence of a cross connection in any one of the condensers 20, 22, and 24 is detected based on an abnormal change in the water level in that one condensed water tank in the same manner as the characteristic operation according to the present embodiment. Is possible.

  In this connection, in the fuel cell system 300, the condensed water discharged from two of the condensed water tanks 26, 27, 28 (for example, the condensed water tanks 26, 27) is transferred to other condensed water tanks ( For example, supply to the condensate water tank 28) and notification of the occurrence of cross-connection in any of the condensers 20, 22, 24 based on an abnormal change in the water level in other condensate water tanks (for example, the condensate water tank 28). It is good also as a form to do. Even with this configuration, it is possible to obtain the same effect as that obtained by the present embodiment.

  On the other hand, in the operation of the fuel cell system 300 according to the present embodiment, the control unit 38 controls the condensed water discharge valves 29, 30, 31 based on the output signals of the water level sensors 35, 36, 37, thereby causing the condensed water tank 26. , 27 and 28 are illustrated as examples of controlling the water level, but the present invention is not limited to such a form. For example, the controller 38 controls the water levels in the condensed water tanks 26, 27, 28 by operating the condensed water discharge valves 29, 30, 31 for a predetermined time without using the water level sensors 35, 36, 37. It is good also as a form. For example, in steps S408 to S410 shown in FIG. 7, the condensed water discharge valve 29 is stopped based on the output signal of the water level sensor 35. However, the water level in the condensed water tank 26 is controlled to a prescribed water level in advance by steps S403 to S405. Therefore, the control unit 38 can lower the water level in the condensed water tank 26 to a desired water level by operating the condensed water discharge valve 29 for a predetermined time.

  In the fuel cell system 300 according to the present embodiment, water level sensors 35, 36, and 37 are provided. However, when there is a reference in the ON signal / OFF signal output from the water level sensors 32, 33, 34, the OFF signals from the water level sensors 32, 33, 34 are detected without providing the water level sensors 35, 36, 37. Until this time, the condensed water discharge valves 29, 30, 31 may be operated.

  The fuel cell system 300 according to the present embodiment is configured such that the hot water discharged from the hot water storage tank 6 passes through the condensers 20, 24, 22 and the heat exchanger 5 in this order. It is not limited to such a configuration. The arrangement order of the condensers 20, 24, 22 and the heat exchanger 5 is any arrangement order as long as the heat exchange between the hot water and the cooling water, the fuel gas, the oxidant gas, and the like is preferably possible. Also good. Moreover, in this Embodiment, although the condenser 20, 24, 22 and the heat exchanger 5 have illustrated the form arrange | positioned in series, it is not limited to such a form and arrange | positions in parallel suitably. It is good also as a form to do.

(Embodiment 6)
FIG. 8 is a block diagram schematically showing the configuration of the fuel cell system according to Embodiment 6 of the present invention. In FIG. 8, only components necessary for explaining the present invention are extracted and shown, and other components are not shown. Further, in FIG. 8, the same components as those of the fuel cell system 200 shown in FIG. 2 are denoted by the same reference numerals, and description of those components will be omitted in the following description.

  As shown in FIG. 8, the configuration of fuel cell system 400 according to Embodiment 6 of the present invention is basically the same as the configuration of fuel cell system 200 according to Embodiments 2 and 3 shown in FIG. is there. However, the configuration of the fuel cell system 400 according to Embodiment 6 of the present invention is different from the configuration of the fuel cell system 200 shown in FIG. 2 in the following three points.

  First, the first difference will be described. The configuration of the fuel cell system 400 according to the present embodiment is a fuel gas humidifier 46 for humidifying a fuel gas and an oxidant gas (air) supplied to the fuel cell 1. And an air humidifier 47, a fuel-side humidified water supply channel 48 for supplying a part of the cooling water stored in the cooling water tank 2 toward the fuel gas humidifier 46 and the air humidifier 47, and the air side A humidified water supply channel 49 and a reforming water supply channel 50 for supplying a part of the cooling water stored in the cooling water tank 2 to the hydrogen generator 17 as water for steam reforming are further provided. This is different from the configuration of the fuel cell system 200 shown in FIG. Here, the fuel-side humidified water supply channel 48, the air-side humidified water supply channel 49, and the reforming water supply channel 50 are configured by piping.

  Next, the second difference will be described. The configuration of the fuel cell system 400 according to the present embodiment is to cut off the supply of hot water in a hot state to the hot water supply equipment in addition to the city water shutoff valve 40. 2 is different from the configuration of the fuel cell system 200 shown in FIG. Here, the hot water shutoff valve 44 is electrically connected to the control unit 38 by wiring in the same manner as the city water shutoff valve 40.

  Further, the third difference will be described. The configuration of the fuel cell system 400 according to the present embodiment replaces the remote control 39 and the alarm device 45 with the fact that an abnormality has occurred due to the occurrence of a cross connection, or the next activation. 2 is different from the configuration of the fuel cell system 200 shown in FIG. 2 in that it includes a signal output device 51 that outputs an electrical signal including the prohibition of the operation as a contact output or an electrical output. The signal output device 51 is an example of a specific embodiment of an abnormality notification device for notifying the occurrence of abnormality due to cross connection.

  In addition, about the other point, the structure of the fuel cell system 200 which concerns on Embodiment 2, 3 and the structure of the fuel cell system 400 which concerns on this Embodiment are the same.

  Next, the operation of the fuel cell system 400 according to the present embodiment will be described.

  In the fuel cell system 400 according to the present embodiment, a steam reforming reaction using a hydrocarbon-based source gas such as city gas and a part of cooling water supplied through the reforming water supply channel 50 is performed. By proceeding in the hydrogen generator 17, hydrogen-rich fuel gas is generated. The fuel gas generated in the hydrogen generator 17 is supplied to the fuel gas humidifier 46 through the fuel gas supply channel 19, and a part of the cooling water supplied by the fuel side humidified water supply channel 48. Is used to adjust its humidity, and then supplied to the fuel cell 1.

  On the other hand, as the oxidant gas containing oxygen, after the humidity is adjusted by using a part of the cooling water supplied from the air-side humidified water supply channel 49 in the air humidifier 47, the fuel cell 1. To be supplied.

  Then, the fuel cell 1 performs a power generation operation by electrochemically reacting the supplied fuel gas and oxidant gas, thereby outputting DC power. The output DC power is converted into AC power by an inverter (not shown), and then supplied to a power load device (not shown).

  During the power generation operation of the fuel cell system 400, part of the supplied fuel gas and oxidant gas is discharged from the fuel cell 1 as residual fuel gas and residual oxidant gas. The discharged residual fuel gas and residual oxidant gas are passed through the residual fuel gas discharge passage 21 and the residual oxidant gas discharge passage 25. Here, after the residual oxidant gas introduced into the condenser 24 via the residual oxidant gas discharge channel 25 is cooled by heat exchange with the hot water, the water vapor contained therein is separated as condensed water. The The separated condensed water is stored in the condensed water tank 28. The residual oxidant gas dehumidified and cooled by the condenser 24 is discharged to the outside of the fuel cell system 400 through the exhaust port. On the other hand, after the residual fuel gas introduced into the condenser 20 through the residual fuel gas discharge passage 21 is cooled by heat exchange with the hot water, the water vapor contained therein is separated as condensed water. The separated condensed water is stored in the condensed water tank 26. The residual fuel gas dehumidified and cooled by the condenser 20 is supplied to a burner 18 for maintaining the hydrogen generator 17 in a high temperature state. The residual fuel gas burned in the burner 18 is discharged from the burner 18 to the combustion exhaust gas discharge passage 23 as combustion exhaust gas in a high temperature state. The combustion exhaust gas introduced into the condenser 22 through the combustion exhaust gas discharge passage 23 is cooled by heat exchange with the hot water, and then the water vapor contained therein is separated as condensed water. The separated condensed water is stored in the condensed water tank 27. Further, the combustion exhaust gas dehumidified and cooled by the condenser 22 is discharged to the outside of the fuel cell system 400 through the exhaust port.

  On the other hand, in the fuel cell 1, heat is generated simultaneously with the generation of DC power during the power generation operation. The heat generated in the fuel cell 1 is sequentially recovered by the cooling water by operating the cooling water circulation pump 4 and passing the cooling water circulating in the cooling water flow path 3 through the fuel cell 1 to exchange heat with the cooling water. The Thus, in the fuel cell system 400, the exhaust heat of the fuel cell 1 is sequentially recovered by the cooling water, so that the temperature of the fuel cell 1 is controlled to an appropriate temperature.

  Here, the cooling water whose temperature has been increased by heat exchange with the fuel cell 1 is then supplied to the heat exchanger 5 where it is cooled by heat exchange with the hot water flowing through the hot water flow path 7 and then cooled. Returned to the water tank 2. The cooling water returned to the cooling water tank 2 is again discharged from the cooling water tank 2 by the cooling water circulation pump 4 and supplied to the fuel cell 1 again. At this time, by operating the hot water circulating pump 8, the hot water stored in the hot water storage tank 6 is supplied to the hot water channel 7 and circulated in the hot water channel 7.

  The hot water supplied from the hot water storage tank 6 to the hot water flow path 7 is supplied to the condensers 20, 24 and 22 while passing through the hot water circulation pump 8 and then flowing through the hot water flow path 7. Then, the hot water is heated by heat exchange in the condensers 20, 24, and 22 and then supplied to the heat exchanger 5. Then, in the heat exchanger 5, the hot water is further heated by exchanging heat with the high-temperature cooling water supplied from the cooling water flow path 3. Then, the hot-water storage water whose temperature has been further increased passes through the hot-water storage channel 7 and is stored in the hot-water storage tank 6 as hot-water storage water in a high temperature state. The stored hot water stored in a high temperature state is supplied from above to a hot water supply device (not shown) for hot water supply, hot water heating, or the like as needed in FIG.

  On the other hand, in the present embodiment, during the power generation operation of the fuel cell system 400, the cooling water stored in the cooling water tank 2 is constantly directed toward the hydrogen generator 17, the fuel gas humidifier 46, and the air humidifier 47. Supplied. Therefore, the water level in the cooling water tank 2 falls. Therefore, when the water level sensor 9 detects a decrease in the water level in the cooling water tank 2, the control unit 38 receives the detection signal and operates the makeup water pump 14 to cool the cooling water stored in the makeup water tank 10 to the cooling water. Supply to tank 2. When the water level sensor 9 detects the return of the water level in the cooling water tank 2 by replenishing the cooling water from the makeup water tank 10, the control unit 38 receives the detection signal and stops the operation of the makeup water pump 14. Then, the supply of the cooling water from the makeup water tank 10 to the cooling water tank 2 is stopped.

  At this time, if the water level sensors 32, 33, and 34 detect an increase in the water level in the condensed water tanks 26, 27, and 28 due to the condensate accumulation, the control unit 38 receives the detection signal and receives the condensed water discharge valve 29. , 30, 31 are operated to discharge excess condensed water stored in the condensed water tanks 26, 27, 28. Thereafter, when the water level sensors 32, 33, and 34 detect the return of the water level in the condensed water tanks 26, 27, and 28 due to the discharge of the condensed water, the control unit 38 receives the detection signal, and the condensed water discharge valves 29, 30, and 31 is shut off, thereby stopping the discharge of the condensed water from the condensed water tanks 26, 27, 28.

  In this fuel cell system 400, in the same manner as the operation specifically described in the second embodiment, the heat exchanger is based on abnormal changes in the water levels in the cooling water tank 2 and the condensed water tanks 26, 27, and 28. 5. The occurrence of cross connection in the condensers 20, 22, and 24 is detected and notified.

  Hereinafter, regarding the operation of the fuel cell system 400 according to the present embodiment, a characteristic operation after an abnormal change in the water level in the cooling water tank 2 and the condensed water tanks 26, 27, and 28 is detected will be described.

  During the power generation operation of the fuel cell system 400, the control unit 38 stops the power generation operation of the fuel cell system 400 when detecting an abnormal change in the water level in the cooling water tank 2 or the condensed water tanks 26, 27, 28. The next activation is prohibited. And the control part 38 interrupts | blocks both the city water shut-off valve 40 and the hot water supply shut-off valve 44, and the inflow of the new city water to the hot water storage tank 6 and the outflow of the hot water from the hot water storage tank 6 are carried out. Prevent both. At this time, the control unit 38 outputs an electrical signal including a message “abnormality detection of change in water level in the cooling water tank or condensate water tank” or “prohibition of next start” by the signal output device 51 or contact output. As output.

  On the other hand, when the power generation operation of the fuel cell system 400 is stopped, the control unit 38 prohibits the next activation of the fuel cell system 400 when detecting an abnormal change in the water level in the cooling water tank 2 or the condensed water tanks 26, 27, 28. To do. And the control part 38 interrupts | blocks both the city water shut-off valve 40 and the hot water supply shut-off valve 44, and the inflow of the new city water to the hot water storage tank 6 and the outflow of the hot water from the hot water storage tank 6 are carried out. Prevent both. At this time, the control unit 38 outputs an electrical signal including a message “abnormality detection of change in water level in the cooling water tank or condensate water tank” or “prohibition of next start” by the signal output device 51 or contact output. As output.

  As described above, according to the configuration of fuel cell system 400 according to the present embodiment, in addition to fuel cell system 200 according to Embodiment 2, the following three additional effects can be further obtained. .

  That is, as a first additional effect, when the control unit 38 detects an abnormal change in the water level in the cooling water tank 2 and the condensers 20, 22, and 24 due to the occurrence of the cross connection, a signal output is performed. Since the electric signal including “detection of abnormality in water level in the cooling water tank or condensate water tank” or “prohibition of next start” is output as a contact output or electric output by the container 51, the remote user or remote It is possible to notify the administrator.

  Further, as a second additional effect, when the control unit 38 detects an abnormal change in the water level in the cooling water tank 2 and the condensers 20, 22, and 24 due to the occurrence of the cross connection, the city water shutoff valve 40 and the hot water supply shut-off valve 44 are both shut off, so that inflow of new city water into the hot water storage tank 6 is prevented, and inflow of hot water storage into the cooling water passage 4 and the condensed water tanks 26, 27, 28 is prevented. The hot water stored in the hot water storage tank 6 is cooled by the head pressure even when hot water is used in a situation where the supply of city water to the hot water storage tank 6 is interrupted. It is possible to prevent the water from flowing into the water flow path 4 and the condensed water tanks 26, 27, and 28.

  Further, as a third additional effect, as in the operation of the fuel cell system 400 according to the present embodiment, a part of the cooling water stored in the cooling water tank 2 is used for the hydrogen generator 17, the fuel gas humidifier 46. In the case where the air is constantly supplied to the air humidifier 47, the operation of the makeup water pump 14 is frequently caused by a drop in the water level in the cooling water tank 2 even during normal operation. Therefore, at the normal time, the operation number counter N1 of the makeup water pump 14 can be secured a certain number of times or more. Therefore, as described in the second embodiment, in the embodiment based on whether or not the operation number counter N1 of the makeup water pump 14 during the time equal to or longer than the predetermined time Tc is equal to or less than the predetermined operation number Nc, the cross connection It becomes possible to detect the occurrence of this more clearly and accurately.

  Other points are the same as those in the first to fifth embodiments.

  The fuel cell system according to the present invention has industrial applicability as a fuel cell system capable of detecting the occurrence of cross connection in the heat exchange means and preventing the abnormal operation state from continuing. .

  The fuel cell system according to the present invention can also be applied to uses such as a cogeneration system that recovers heat generated together with power generation using an engine or the like.

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Cooling water tank 2a Overflow pipe 3 Cooling water flow path 4 Cooling water circulation pump 5 Heat exchanger 6 Hot water storage tank 7 Hot water storage water flow path 8 Hot water storage water circulation pump 9, 12, 15 Water level sensor 32-37 Water level sensor 41-43 Water level sensor DESCRIPTION OF SYMBOLS 10 Supply water tank 11a Supply water valve 11b Discharge water valve 13,38 Control part 13a Abnormal indicator 13b Water level controller 14 Supply water pump 16 Cooling water discharge valve 17 Hydrogen generator 18 Burner 19 Fuel gas supply flow path 20,22, 24 Condenser 21 Residual fuel gas discharge flow path 23 Combustion exhaust gas discharge flow path 25 Residual oxidant gas discharge flow path 26, 27, 28 Condensate water tank 29, 30, 31 Condensate water discharge valve 39 Remote control 39 a Abnormal indicator 40 City water Shut-off valve 44 Hot-water supply shut-off valve 45 Alarm 46 Fuel gas humidifier 47 Air humidifier 48 Fuel side Humidification water supply flow path 49 Air-side humidification water supply flow path 50 Reformed water supply flow path 51 Signal output unit 101 Power generation unit 102 Reformer 103 Fuel cell 104 Hot water storage tank 105 Hot water storage water circulation pipe 106 Waste heat recovery means 109 Sensible heat recovery Heat exchanging part 110 Cooling water exhaust heat recovery heat exchanging part 111 Latent heat recovery heat exchanging part 112 Cooling water circulation piping 100 to 500 Fuel cell system

Claims (3)

A fuel cell that generates power using fuel gas and oxidant gas;
A hot water storage tank for storing hot water for recovering exhaust heat related to power generation of the fuel cell;
A combustor for burning the fuel gas discharged from the fuel cell;
A heat exchanger for exchanging heat between the hot water from the hot water storage tank and the fuel gas or oxidant gas discharged from the fuel cell or the combustion exhaust gas discharged from the combustor ;
A condensed water tank for storing condensed water from the fuel gas or the oxidant gas or the combustion exhaust gas after heat exchange with the hot water in the heat exchanger;
A water level sensor for detecting the water level in the condensed water tank;
An abnormality alarm device that notifies the occurrence of abnormality based on the water level detected by the water level sensor;
Water ejector to change more level of the condensed water tank to the exit of water discharge from the previous SL condensed water tank,
When the water level sensor detects an increase in the water level in the condensed water tank when the operation of the water discharger is stopped and the fuel cell is stopped, an abnormality is notified to the abnormality notifier. fuel cell system and a Ru control device is. An operation controller for controlling the operation of the fuel cell system;
2. The fuel cell system according to claim 1, wherein the operation controller stops the operation of the fuel cell system when the control device causes the abnormality notifier to notify the occurrence of an abnormality. An operation controller for controlling the operation of the fuel cell system;
2. The fuel cell system according to claim 1, wherein the operation controller does not permit a transition from operation stop to operation start of the fuel cell system when the control device detects an increase in the water level by the water level sensor.

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