JP2010238473A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect whether supply of water to a fuel cell module is insufficient or not when condensed water from a condenser is supplied to the fuel cell module in a fuel cell system. <P>SOLUTION: The fuel cell system includes: a fuel cell module 20 including at least a fuel cell 24 and to which water, fuel, and oxidant gas are supplied; a condenser 33 condensing steam in combustion exhaust gas exhausted from the fuel cell module 20 by heat exchange with a heating medium; a water tank 13 storing condensed water supplied from the condenser 33; a drainage 70 including a water receiving member 71 arranged within a casing 11 and receiving at least water that has overflowed from the water tank 13 and a drain pipe 72 draining the received water from the water receiving member 71 to the outside of the casing 11; and a conductivity meter 72a installed in the drainage 70 and detecting conductivity of drain. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel cell system.

  An example of the fuel cell system is a fuel cell system disclosed in Patent Document 1. As shown in FIG. 2 of Patent Document 1, this fuel cell system includes a reformer 4 that performs steam reforming, and a water supply pipe 5 for supplying water to the reformer 4, A water supply valve 6 provided in the water supply pipe 5 for adjusting the amount of water supplied to the water supply pipe 5, a water treatment device for processing the water supplied to the reformer 4, and the supply to the reformer 4 A water tank 10 for storing water to be stored, and a control device 14 for controlling the opening and closing of the water supply valve 6 based on the water level of the water tank 10, as well as the water supply valve 6, the activated carbon filter device 7, the RO membrane device 8, A water tank 10 and an ion exchange resin device 9 are sequentially connected to a reformer 4 by a water supply pipe 5. Further, condensed water generated when the exhaust gas generated by the power generation of the fuel cell 1 is exchanged with the water flowing through the heat exchanger 13 is supplied to the water tank 10 through the condensed water supply pipe 20.

  In this fuel cell system, a conductivity sensor (water flow sensor) 19 for detecting the conductivity of water flowing through the water supply pipe 5 is provided between the water supply valve 6 and the water tank 10, and the water supply valve 6 is closed. When the water flow sensor 19 detects water flowing through the water supply pipe 5 after a predetermined time has elapsed, it can be seen that the water supply valve 6 has failed.

JP 2008-186661 A

  However, in the fuel cell system described in Patent Document 1, the water supply valve 6 for supplying water to the reformer based on the detected value of the conductivity sensor 19 that detects the conductivity of the water flowing through the water supply pipe 5. Although it is possible to easily determine the failure, it is possible to determine whether the condensed water (recovered water) from the heat exchanger 13 (condenser) is more or less than the water (supply water) supplied to the fuel cell module. That is, it cannot be determined whether there is a shortage of water supplied to the fuel cell module.

  The present invention has been made to solve the above-described problem. In the fuel cell system, when the condensed water from the condenser is supplied to the fuel cell module, is the water supplied to the fuel cell module insufficient? It aims to make it possible to detect whether or not.

  In order to solve the above-described problem, the structural feature of the invention according to claim 1 is a fuel cell system including a fuel cell module that includes at least a fuel cell and is supplied with water, fuel, and oxidant gas. The water vapor in the gas containing water circulating in the fuel cell system is condensed by heat exchange with the liquid heat medium to generate condensed water, and the condensed water supplied from the condenser is A storage reservoir, a water supply means for supplying condensed water stored in the reservoir to the fuel cell module as water, a drainage device for discharging water overflowing from the reservoir, and a drainage device provided in the drainage device And a conductivity meter for detecting the conductivity of.

  Further, the structural feature of the invention according to claim 2 is that, in claim 1, the fuel cell module, the condenser, the water reservoir, and the drainage device are disposed in the casing, and the drainage device is water that overflows from the water reservoir. A water receiving member that receives at least water, and a drain pipe that discharges the received water from the water receiving member to the outside of the housing.

  The structural feature of the invention according to claim 3 is that in claim 2, further comprising a water conduit provided in the water reservoir for guiding the water overflowing from the water reservoir to the water receiving member.

  Further, the structural feature of the invention according to claim 4 is that, in claim 2 or claim 3, the water receiving member is disposed below the water reservoir and is configured to receive water that leaks from the water reservoir and falls. It has been done.

  According to a fifth aspect of the present invention, in any one of the second to fourth aspects, the water receiving member is configured to receive a heat medium that leaks from the condenser and falls. That is.

  Further, the structural feature of the invention according to claim 6 is that, in claim 3, the water storage device comprises a deionizer that purifies condensed water supplied from the condenser, and deionized water supplied from the deionizer. And a water tank for storing water, a first water conduit provided in the water tank for guiding water overflowing from the water tank to the water receiving member, and water overflowing from the water purifier provided in the water purifier for the water receiving member. At least one of the second water guide pipes to be led is provided as a water guide pipe.

  Further, the structural feature of the invention according to claim 7 is that, in any one of claims 1 to 6, hot water is stored, hot hot water is supplied from above, and low temperature replenishment is provided by the decrease. A hot water tank that replenishes water from the bottom, and a hot water tank that has one end connected to the lower part of the hot water tank and the other end connected to the upper part of the hot water tank, and a condenser provided in the middle of the hot water tank. A hot water pipe connected to a hot water circulation line between the hot water inlet of the hot water tank and the hot water outlet of the condenser and a hot water pipe for draining the hot water after heat exchange in the condenser to the drainage device; And a hot water valve provided in the hot water pipe for opening and closing the hot water pipe.

  A structural feature of the invention according to claim 8 is the control device according to any one of claims 1 to 7, wherein the control device controls operation of the fuel cell system based on the conductivity value measured by the conductivity meter. The control device is to stop the fuel cell system when the conductivity value of the drainage of the drainage device is equal to or higher than the first predetermined value.

  A structural feature of the invention according to claim 9 is the control device according to any one of claims 1 to 7, wherein the control device controls operation of the fuel cell system based on the conductivity value measured by the conductivity meter. When the conductivity value of the drainage of the drainage device is equal to or less than the second predetermined value, the control device determines that the water supplied to the fuel cell module is insufficient and the water supplied to the fuel cell module It is to control the fuel cell system to increase.

  In addition, a structural feature of the invention according to claim 10 is the control device according to claim 7, further comprising a control device that controls the operation of the fuel cell system based on the conductivity value measured by the conductivity meter. If the drainage device's drainage conductivity value is greater than or equal to the third predetermined value even though the hot water valve is instructed to close, or the drainage device's When the conductivity value is equal to or lower than the fourth predetermined value, the fuel cell system is stopped.

  In the invention according to claim 1 configured as described above, the drainage device condenses the water vapor in the gas containing moisture flowing in the fuel cell system by heat exchange with the liquid heat medium to condense water ( The condensed water is supplied to the fuel cell module as water), and the overflowed water is discharged from the water reservoir that stores the condensed water supplied from the condenser. The conductivity meter is provided in the drainage device and detects the conductivity of the drainage.

  As a result, firstly, when there is no other abnormality such as leakage of the heat medium from the condenser when water does not overflow from the water reservoir during start-up operation or power generation operation of the fuel cell system, the drainage device Since no liquid is discharged outside through the conductivity meter, the conductivity meter shows almost zero. On the other hand, when water overflows from the water reservoir, the overflowed water is drained to the outside through a drainage device, and the conductivity of the drainage is detected by a conductivity meter. In addition, overflowing water from the reservoir indicates that the condensed water (recovered water) from the condenser is more than the water (supply water) supplied to the fuel cell module, while water from the reservoir is The fact that the water does not overflow indicates that the amount of recovered water is equal to or less than the amount of water supplied. From the above, based on the detection result of the conductivity meter provided in the drainage device, the condensed water (recovered water) from the condenser is assumed to be free of other abnormalities such as leakage of the heat medium from the condenser. It is possible to determine whether the amount of water supplied to the fuel cell module is greater (supply water), that is, it is possible to determine whether the amount of water supplied to the fuel cell module is insufficient.

  Secondly, when the fuel cell system is submerged, external water (for example, water during flooding, which generally has higher conductivity than the recovered water of the fuel cell system in a normal state) enters the drainage device (backflows). ) And the external water has a high conductivity, so the measured value of the conductivity meter is relatively high. Therefore, by utilizing this fact, it is possible to detect external water intruding into the drainage device, that is, to detect the flooding of the fuel cell system reliably and accurately. The battery system can be stopped early.

  Third, when the fuel cell deteriorates or fails and the fine particles of the catalyst of the electrode of the fuel cell are included in the combustion exhaust gas, the electrolyte in the condensed water condensed in the condenser increases, and the condensed water The conductivity increases. Further, when water having a relatively high conductivity (condensed water) overflows from the water tank, the overflowed water is drained to the outside through the drainage device, and the conductivity of the drainage is determined by the conductivity meter. Detected by. At this time, since the conductivity meter detects a higher conductivity than normal condensed water, there should be no other abnormalities such as leakage of the heat medium from the condenser based on the detection result of the conductivity meter provided in the drainage device. Therefore, it is possible to determine the deterioration or failure of the fuel cell. When it is determined that the fuel cell has deteriorated or failed, the fuel cell system can be stopped.

  Fourthly, even if the partition between the gas line and the heat medium line in the condenser is broken and the heat medium flows into the condensed water line, the overflow water has a higher conductivity than the normal condensed water. By detecting the rate, the fuel cell system can be stopped based on the detection result of the conductivity meter provided in the drainage device. Thereby, it is possible to prevent deterioration and failure caused by sending water having high conductivity to the fuel cell module.

  In the invention according to claim 2 configured as described above, in claim 1, the fuel cell module, the condenser, the water reservoir, and the drainage device are disposed in the casing, and the drainage device overflows from the water reservoir. A water receiving member that receives at least water and a drain pipe that discharges the received water from the water receiving member to the outside of the housing are provided. Thus, in the fuel cell system in which the fuel cell module, the condenser, the water reservoir, and the drainage device are disposed in the housing, the same operation and effect as in the first aspect can be obtained.

  The invention according to claim 3 configured as described above further includes a water guide pipe provided in the water reservoir for guiding the water overflowing from the water reservoir to the water receiving member. As a result, the water overflowing from the water reservoir can be reliably guided to the drainage device, and as a result, it can be determined whether the water supplied to the fuel cell module is insufficient.

  In the invention according to claim 4 configured as described above, in claim 2 or claim 3, the water receiving member is disposed below the water reservoir so as to receive water that leaks from the water reservoir and falls. It is configured. Thereby, the water receiving member can reliably receive and drain the water that leaks or overflows from the water reservoir, and the conductivity of these liquids can be reliably detected.

  In the invention according to Claim 5 configured as described above, in any one of Claims 2 to 4, the water receiving member is configured to receive a heat medium that leaks from the condenser and falls. Yes. As a result, if the heat medium leaks from a condenser or a member through which the heat medium flows, such as a supply pipe that supplies the heat medium to the condenser, the leaked heat medium is drained to the outside through the drainage device. The conductivity is detected by a conductivity meter. In general, the conductivity of the heat medium is larger than the conductivity of condensed water condensed in a normal condenser. In other words, if the conductivity meter detects a higher conductivity than normal condensate, the heat medium may have leaked from a condenser or a member through which the heat medium flows, such as a supply pipe that supplies the heat medium to the condenser. It becomes possible to judge. When it is determined that the heat medium has leaked, the fuel cell system can be stopped.

  In the invention according to claim 6 configured as described above, in claim 3, the water storage device includes a deionizer that purifies condensed water supplied from the condenser, and a deionizer supplied from the deionizer. A water tank for storing water and water, a first water conduit provided in the water tank for guiding the water overflowing from the water tank to the water receiving member, and a water receiving member for the water overflowing from the water purifier provided in the pure water device At least one of the second water guide pipes led to is provided as a water guide pipe. Thereby, the water overflowing from the water tank can be reliably guided to the drainage device by the first conduit, and the water overflowing from the deionizer can be reliably guided to the drainage device by the second conduit. As a result, it is possible to determine whether water supplied to the fuel cell module is insufficient.

  In the invention according to claim 7 configured as described above, in any one of claims 1 to 6, hot water is stored, hot hot water is supplied from above, and the temperature is reduced by the reduced amount. A hot water tank for replenishing makeup water from the bottom, one end connected to the lower part of the hot water tank, the other end connected to the upper part of the hot water tank, and a condenser provided along the way, supplying the hot water to the condenser as a heat medium A hot water circulation line, a hot water pipe that is connected to a hot water circulation line between the hot water inlet of the hot water tank and the hot water outlet of the condenser, and drains the hot water after heat exchange with the condenser to the drainage device; And a hot water valve provided on the hot water pipe for opening and closing the hot water pipe. Accordingly, when the hot water discharge valve is opened, the heat medium heated by the condenser is discharged outside through the hot water pipe without returning to the hot water storage tank. Along with this, low temperature makeup water is supplied from the lower part of the hot water tank, and the low temperature makeup water is supplied to the condenser. In the condenser, the amount of condensed water generated is increased by a low-temperature heat medium. Therefore, when the condensed water (recovered water) from the condenser is less than the water (supply water) supplied to the fuel cell module, that is, when the water supplied to the fuel cell module is insufficient, the drain valve is opened. Thus, the shortage of water supplied to the fuel cell module can be solved by increasing the supply amount of the condensed water.

  In the invention according to claim 8 configured as described above, the control for controlling the operation of the fuel cell system based on the conductivity value measured by the conductivity meter according to any one of claims 1 to 7. The apparatus further includes a device, and the control device stops the fuel cell system when the conductivity value of the drainage of the drainage device becomes equal to or higher than the first predetermined value. As a result, it was detected that the heat medium leaked from the condenser or the member through which the heat medium flows, such as a supply pipe that supplies the heat medium to the condenser, that the fuel cell system was submerged, and that the fuel cell was deteriorated or failed. In this case, the fuel cell system can be reliably stopped.

  In the invention according to claim 9 configured as described above, the control for controlling the operation of the fuel cell system according to any one of claims 1 to 7 based on the conductivity value measured by the conductivity meter. The apparatus further includes a device, and when the conductivity value of the drainage of the drainage device is equal to or less than the second predetermined value, the control unit determines that the water supplied to the fuel cell module is insufficient and supplies the fuel cell module with water. The fuel cell system is controlled so as to increase. Thereby, it can be judged reliably that the water supplied to the fuel cell module is insufficient. And even when the hot water tank is in a state of excessive heat, the hot water heated by the condenser is opened by draining the hot water valve, and low temperature hot water is supplied from the hot water tank to the condenser. Thus, it is possible to reliably eliminate the shortage of water supplied to the fuel cell module by increasing the collected condensed water.

  In the invention according to claim 10 configured as described above, in claim 7, further comprising a control device that controls the operation of the fuel cell system based on the conductivity value measured by the conductivity meter, Drainage of the drainage device when the drainage device's drainage conductivity value is greater than or equal to the third predetermined value even though the drainage valve is instructed to close or the drainage device is instructed to open. The fuel cell system is stopped when the electrical conductivity value is less than or equal to the fourth predetermined value. Thereby, the abnormality of the hot water valve can be accurately determined, and the fuel cell system can be appropriately stopped.

1 is a schematic diagram showing an outline of an embodiment of a fuel cell system according to the present invention. 1 is a configuration block diagram showing an electrical configuration of an embodiment of a fuel cell system according to the present invention. It is a block diagram which shows the fuel cell system shown in FIG. 4 is a flowchart of a control program executed by the control device shown in FIG. 3. It is a figure which shows the water balance of the fuel cell system shown in FIG. It is a schematic diagram which shows the outline | summary of other embodiment of the fuel cell system by this invention. It is a schematic diagram which shows the outline | summary of other embodiment of the fuel cell system by this invention.

  Hereinafter, an embodiment of a fuel cell system according to the present invention will be described. FIG. 1 is a schematic diagram showing an outline of this fuel cell system. This fuel cell system includes a box-shaped casing 11, a fuel cell module 20, an exhaust heat recovery system 30, an inverter device 50, a fuel cell system control device (hereinafter referred to as a control device) 60, and a drain device 70. .

The case 11 includes a partition member 12 that partitions the inside of the case 11 and forms a first chamber R1 and a second chamber R2. The partition member 12 is a plate-like member that partitions (divides) the casing 11 in the vertical direction. A first chamber R1 and a second chamber R2 are formed in the housing 11 above and below the partition member 12. In the present embodiment, the partition member 12 is composed of a single plate-shaped member. However, the partition member 12 may be composed of a box-shaped member, and each of the first chamber R1 and the second chamber R2 is configured as a box-shaped member. You may comprise by two separate members formed in the box shape which divides.

  The fuel cell module 20 is accommodated in the first chamber R1 with a space from the inner wall surface of the first chamber R1. The fuel cell module 20 includes at least a casing 21 and a fuel cell 24. In the present embodiment, the fuel cell module 20 includes a casing 21, an evaporation unit 22, a reforming unit 23, and a fuel cell 24.

  The casing 21 is formed in a box shape with a heat insulating material. The casing 21 is supported in the first chamber R1 by a support structure (not shown) with a space from the inner wall surface of the first chamber R1. Note that any surface of the casing 21 may not be in contact with the inner wall surface of the first chamber R1, that is, one of the surfaces (six surfaces) of the casing 21 is a space between the inner wall surface of the first chamber R1. If there is. In the casing 21, an evaporation unit 22, a reforming unit 23, and a fuel cell 24 are disposed. At this time, the evaporation unit 22 and the reforming unit 23 are disposed above the fuel cell 24.

  The evaporation unit 22 is heated by a combustion gas, which will be described later, to evaporate the supplied reforming water to generate water vapor, and to preheat the supplied reforming raw material. The evaporation unit 22 mixes the steam generated in this way with the preheated reforming raw material and supplies it to the reforming unit 23. Examples of the reforming raw material include natural gas, gas fuel for reforming such as LPG, and liquid fuel for reforming such as kerosene, gasoline, and methanol. In the present embodiment, description will be made on natural gas.

  One end (lower end) of the water supply pipe 41 provided in the pure water tank 13 is connected to the evaporation unit 22. The water supply pipe 41 is provided with a reforming water pump (water supply means) 41a. The reforming water pump 41a supplies reforming water to the evaporation unit 22 and adjusts the reforming water supply amount. The reforming water pump 41a supplies condensed water stored in the pure water tank 13 serving as the water reservoir 16 to the fuel cell module 20 as reforming water (water).

  The evaporating unit 22 is supplied with a reforming material from a fuel supply source (not shown) through a reforming material supply pipe 42. The reforming raw material supply pipe 42 is provided with a pair of raw material valves (not shown), a desulfurizer 42a, and a raw material pump 42b in order from the upstream. The raw material valve is an electromagnetic on-off valve that opens and closes the reforming raw material supply pipe 42. The desulfurizer 42a removes a sulfur content (for example, a sulfur compound) in the reforming raw material. The raw material pump 42b adjusts the fuel supply amount from the fuel supply source, and the discharge amount thereof is adjusted and controlled (for example, controlled according to the load power amount (power consumption amount) of the fuel cell 24). .

  The reforming unit 23 is heated by a combustion gas, which will be described later, and supplied with heat necessary for the steam reforming reaction, so that the reformed gas is generated from the mixed gas (reforming raw material, steam) supplied from the evaporation unit 22. Is generated and derived. The reforming unit 23 is filled with a catalyst (for example, Ru or Ni-based catalyst), and the mixed gas reacts with the catalyst to be reformed to generate hydrogen gas and carbon monoxide gas (so-called so-called). Steam reforming reaction). At the same time, a so-called carbon monoxide shift reaction occurs in which carbon monoxide generated in the steam reforming reaction reacts with steam to transform into hydrogen gas and carbon dioxide. These generated gases (so-called reformed gas) are led out to the fuel electrode of the fuel cell 24. The reformed gas contains hydrogen, carbon monoxide, carbon dioxide, water vapor, and unreformed natural gas (methane gas). The steam reforming reaction is an endothermic reaction, and the carbon monoxide shift reaction is an exothermic reaction.

  The fuel cell 24 is configured by laminating a fuel electrode, an air electrode (oxidant electrode), and a plurality of cells 24a formed in a plate shape made of an electrolyte interposed between the two electrodes. The fuel cell of the present embodiment is a solid oxide fuel cell, and uses zirconium oxide, which is a kind of solid oxide, as an electrolyte. Hydrogen, carbon monoxide, and methane gas are supplied to the fuel electrode of the fuel cell 24 as fuel. The operating temperature is about 700-1000 ° C. Not only hydrogen but also natural gas and coal gas can be used directly as fuel. In this case, the reforming unit 23 can be omitted.

  On the fuel electrode side of the cell 24a, a fuel flow path 24b through which a reformed gas that is a fuel flows is formed. An air flow path 24c through which air (cathode air) that is an oxidant gas flows is formed on the air electrode side of the cell 24a.

  The fuel cell 24 is provided on the manifold 25. The manifold 25 is supplied with the reformed gas from the reforming unit 23 via the reformed gas supply pipe 43 and the cathode air is supplied via the cathode air supply pipe 44. The lower end (one end) of the fuel flow path 24b is connected to the fuel outlet port of the manifold 25, and the reformed gas led out from the fuel outlet port is introduced from the lower end and led out from the upper end. . The lower end (one end) of the air flow path 24c is connected to the cathode air supply pipe 44 via the air manifold, and the cathode gas led out from the cathode air supply pipe 44 is introduced from the lower end and led out from the upper end. It is like that.

  One end of the cathode air supply pipe 44 is connected to an air manifold (not shown), and the other end is connected to a cathode air blower 44a (cathode air sending (air blowing) means). The cathode air blower 44a is disposed in the second chamber R2. The cathode air blower 44a sucks the air in the second chamber R2 and discharges it to the air electrode of the fuel cell 24. The discharge amount is adjusted and controlled (for example, the load power amount (power consumption amount) of the fuel cell 24). Are controlled accordingly).

In the fuel cell 24, power generation is performed by the fuel supplied to the fuel electrode and the oxidant gas supplied to the air electrode. That is, the reaction shown in Chemical Formula 1 and Chemical Formula 2 below occurs at the fuel electrode, and the reaction shown in Chemical Formula 3 below occurs at the air electrode. That is, oxide ions (O ²⁻ ) generated at the air electrode permeate the electrolyte and react with hydrogen at the fuel electrode to generate electrical energy. Therefore, the reformed gas and the oxidant gas (air) that have not been used for power generation are derived from the fuel flow path 24b and the air flow path 24c.

(Chemical formula 1)
H ₂ + O ²⁻ → H ₂ O + 2e ⁻

(Chemical formula 2)
CO + O ²⁻ → CO ₂ + 2e ⁻

(Chemical formula 3)
1 / 2O ₂ + 2e ⁻ → O ²⁻

  The reformed gas derived from the fuel flow path 24b and the air flow path 24c and not used for power generation is generated in the combustion space R3 between the fuel cell 24 and the evaporation section 22 (reforming section 23). The oxidant gas (air) that has not been used is combusted, and the evaporation part 22 and the reforming part 23 are heated by the combustion gas. Furthermore, the inside of the fuel cell module 20 is heated to the operating temperature. Thereafter, the combustion gas is exhausted from the fuel cell module 20 through the outlet 21a.

  The exhaust heat recovery system 30 includes a hot water tank 31 for storing hot water, a hot water circulation line 32 for circulating the hot water, and a first heat exchange between the combustion exhaust gas from the fuel cell module 20 and the hot water. And a heat exchanger 33.

  The hot water storage tank 31 is provided with one columnar container, in which hot water is stored in a layered manner, that is, the temperature of the upper part is the highest and lower as it goes to the lower part, and the temperature of the lower part is the lowest. It has become so. Under the columnar container of the hot water tank 31, water such as tap water (low temperature make-up water) is supplied from the supply pipe 31 a, and the hot hot water (hot water) stored in the hot water tank 31 is the columnar container of the hot water tank 31. The lead-out pipe (hot-water supply lead-out pipe) 31b is led out (hot water supply) from the top of the pipe.

  One end of the hot water circulation line 32 is connected to the lower part of the hot water tank 31, and the other end of the hot water circulation line 32 is connected to the upper part of the hot water tank 31. On the hot water circulation line 32, a hot water circulation pump 32a, a radiator 32b, a first heat exchanger 33, and a temperature sensor 32c, which are hot water circulation means, are arranged in order from one end to the other end. The hot water circulating pump 32a sucks in hot water stored in the lower part of the hot water tank 31, passes the hot water circulating line 32 in the direction of the arrow in the drawing, and discharges it to the upper part of the hot water tank 31, and its flow rate (delivery amount) is controlled. It is controlled by the device 60. The radiator 32b cools the hot water storage and includes, for example, a cooling fan (not shown). The radiator 32b is driven / stopped by a command from the control device 60, is driven by the drive command, cools the stored hot water, stops driving by the drive stop command, and stops cooling the stored hot water. The temperature sensor 32c detects the inlet temperature of the hot water storage tank 31 and transmits the detection result to a control device (not shown). The hot water circulating pump 32a is controlled in its delivery amount so that the temperature detected by the temperature sensor 32c (the inlet temperature of the hot water storage tank 31) is within a predetermined temperature or temperature range.

  The first heat exchanger (condenser) 33 is a condenser that condenses the water vapor in the gas containing moisture flowing in the fuel cell system by heat exchange with the liquid heat medium to generate condensed water. The first heat exchanger (condenser) 33 is a heat exchanger in which combustion exhaust gas exhausted from the fuel cell module 20 is supplied and hot water stored in the hot water storage tank 31 is supplied to exchange heat between the combustion exhaust gas and hot water. is there. The first heat exchanger 33 is disposed in the housing 11. In the present embodiment, the first heat exchanger 33 is provided in the lower part of the fuel cell module 20, and at least the lower part of the first heat exchanger 33 penetrates the partition member 12 and protrudes into the second chamber R2. Arranged.

  The first heat exchanger 33 includes a casing 33a. The casing 33a is provided with an introduction port 33b through which combustion exhaust gas is introduced, a discharge port 33c through which combustion exhaust gas is derived, and a discharge port 33d through which condensed condensed water is derived. A heat exchanging part (condensing part) 33e connected to the hot water circulation line 32 is disposed in the casing 33a. The introduction port 33b is provided in the lower part of the casing 21 of the fuel cell module 20, and communicates with the outlet port 21a from which the combustion exhaust gas is led out. The combustion exhaust outlet port 33 c is connected to the first exhaust port 11 a via the exhaust pipe 45. The condensed water outlet 33d is formed at the bottom of the casing 33a. The combustion exhaust gas outlet 33c is formed above the condensed water outlet 33d in order to prevent the condensed water from being led out from the combustion exhaust gas outlet 33c.

  In the first heat exchanger 33 configured as described above, the combustion exhaust gas from the fuel cell module 20 is introduced into the casing 33a from the introduction port 33b, and passes through the heat exchange unit 33e through which the hot water (heat medium) flows. As it passes, heat is exchanged with the hot water and condensed and cooled. The condensed combustion exhaust gas is discharged to the outside through the outlet port 33c and the exhaust pipe 45 from the first exhaust port 11a. Condensed condensed water is supplied to the deionizer 14 through the condensed water outlet 33d and the condensed water supply pipe 46 (it falls by its own weight). On the other hand, the hot water stored in the heat exchange unit 33e is heated and discharged.

  In addition, a hot water discharge pipe 34 is connected to the hot water storage water circulation line 32. The upper end of the hot water discharge pipe 34 is connected to a hot water circulation line 32 between the hot water inlet of the hot water tank 31 and the hot water outlet of the first heat exchanger 33. The lower end of the hot water discharge pipe 34 extends downward and extends to a position above the water receiving member 71 of the drainage device 70. Hot water stored in the hot water circulation line 32 (hot water stored between the hot water inlet of the hot water tank 31 and the hot water outlet of the first heat exchanger 33) is guided to the drainage device 70 through the hot water pipe 34. It has become.

  Further, the hot water pipe 34 is provided with a hot water valve 34 a for opening and closing the hot water pipe 34. The hot water discharge valve 34 a is an electromagnetic valve that is controlled to open and close according to an instruction from the control device 60. When the hot water discharge valve 34a is opened, the hot water stored after the heat exchange in the first heat exchanger 33 is guided (drained) to the drainage device 70 through the hot water pipe 34, and the hot water valve 34a is When closed, the hot water stored in the first heat exchanger 33 is not led to the drainage device 70 through the drain pipe 34 (not drained).

  Further, the fuel cell system includes a water reservoir 16 that stores the condensed water supplied from the condenser 33. The water reservoir 16 includes a pure water tank 13 and a pure water reservoir 14. The pure water tank 13 and the pure water device 14 are disposed in the second chamber R2.

  The pure water tank 13 stores pure water derived from the pure water device 14 (that is, water after being processed by the pure water device 14) (a container for storing liquid). The pure water tank 13 is provided with a water amount sensor (water level sensor) (not shown) that detects the amount of pure water in the pure water tank 13. The water amount sensor is, for example, a float type or capacitance type water level gauge. The water amount sensor transmits a detection signal to the control device 60.

  The pure water tank 13 is provided with an overflow line (first water conduit) 13b. The upper end of the overflow line 13 b is connected to the upper part of the pure water tank 13. The lower end of the overflow line 13 b extends downward and extends to a position above the water receiving member 71 of the drainage device 70. Pure water overflowing from the pure water tank 13 is guided to the drainage device 70 through the overflow line 13b. Moreover, the upper part of the pure water tank 13 may not be sealed without sealing. When the fuel cell system is submerged, external water enters the pure water tank 13 from the overflow line 13b or the upper unsealed portion. The overflow line 13 b is a water guide pipe 17 that is provided in the pure water tank 13 that is the water reservoir 16 and guides the water overflowing from the pure water tank 13 to the water receiving member 71.

  The pure water device 14 contains activated carbon and an ion exchange resin, and is filled with, for example, flaky activated carbon and a granular ion exchange resin. Depending on the state of the water to be treated, a hollow fiber filter may be installed. The deionizer 14 includes a folded channel (substantially U-shaped). The side to which the condensed water supply pipe 46 is connected is the inlet side, and the side to which the pipe 47 is connected is the outlet side. The deionizer 14 purifies the condensed water from the first heat exchanger 33 with activated carbon and an ion exchange resin. The deionizer 14 communicates with the deionized water tank 13 through a pipe 47, and the deionized water in the deionizer 14 is led to the deionized water tank 13 through the pipe 47. If the water quality of the condensed water is good for the required water quality of the fuel cell 24, the deionizer 14 need not be provided.

  Further, the fuel cell system includes a drainage device 70 and a conductivity meter 72a. The drainage device 70 includes a water receiving member 71 and a drain pipe 72. The water receiving member 71 is disposed in the housing 11 and receives at least water overflowing from the pure water tank 13. In the present embodiment, the water receiving member 71 is a container formed in a tray shape having an opening 71a that opens upward and a flat bottom 71b. Immediately above the opening 71 a of the water receiving member 71, the lower ends of the overflow line 13 b and the hot water discharge pipe 34 are disposed. As a result, the water receiving member 71 can reliably receive the water overflowing from the pure water tank 13 via the overflow line 13b, and reliably discharge the hot water from the hot water circulation line 32 via the hot water pipe 34. Can receive.

  Further, the water receiving member 71 is disposed below at least all of the connection position of the overflow line 13 b of the pure water tank 13 (the overflow port of the pure water tank 13) and the upper end position of the hot water discharge pipe 34.

  A drain pipe 72 is connected to the bottom 71b. The drain pipe 72 discharges the water received by the water receiving member 71 from the water receiving member 71 to the outside of the casing 11. The upper end of the drain pipe 72 is connected to the lower surface of the bottom 71b, the lower end of the drain pipe 72 is extended downward, penetrates the lower part of the casing 11 (bottom of the bottom plate and side plates), and projects outside the casing 11. ing. In addition, it is preferable that the structure of the bottom part 71b is comprised so that water may flow toward the part to which the drain pipe 72 is connected.

  The conductivity meter 72a is provided in the vicinity of the drain pipe 72 and the water receiving member 71, particularly a portion where the received water flows, for example, the drain pipe 72 to which the drain pipe 72 is connected. The conductivity meter 72a detects the conductivity of the drainage discharged from the drainage device 70. The detection result of the conductivity meter 72 a is transmitted to the control device 60. The conductivity meter 72 a may be provided in the water receiving portion of the water receiving member 71. In this case, the drain pipe 72 is preferably connected to the side surface of the water receiving member 71. Further, an ohmmeter may be used instead of the conductivity meter. The conductivity meter and the resistance meter are substantially equivalent.

  Furthermore, in the fuel cell system, the first chamber R1 includes an air inlet 12a for introducing air from the outside into the first chamber R1, and an air outlet (second second) for guiding the air in the first chamber R1 to the outside. An exhaust port) 11b, and a ventilation air blower (blower unit) 15 provided on the flow passage through which air flows from the air introduction port 12a to the air outlet port 11b to send the air (ventilation air). I have.

  The air introduction port 12 a is formed in the partition member 12. The air inlet 12a may be formed in the housing 11 that forms the first chamber R1. The 2nd exhaust port 11b is formed in the housing | casing 11 which forms 1st chamber R1. The ventilation air blower 15 is provided in the air inlet 12a. The ventilation air blower 15 sucks the air in the second chamber R2 and sends it out into the first chamber R1 through the air inlet 12a. The air passage from the air introduction port 12a to the air outlet port 11b includes the air inlet port 12a and the air outlet port 11b. The second chamber R2 is provided with an air introduction port 11c for introducing air from the outside into the second chamber R2.

  Thereby, the air in the second chamber R2 is sent into the first chamber R1 through the air inlet 12a by driving the ventilation air blower 15. The ventilation air introduced into the first chamber R1 circulates between the inner wall surface of the first chamber R1 and the casing 21 toward the air outlet 11b, and is discharged to the outside from the air outlet 11b.

  Further, the fuel cell system includes an inverter device (power conversion device) 50. The inverter device 50 has a first function of inputting a DC voltage output from the fuel cell 24, converting the DC voltage to a predetermined AC voltage, and outputting the AC voltage to a power line 52 connected to an AC system power supply 51 and an external power load 53. And a second function of inputting an AC voltage from the system power supply 51 through the power supply line 52, converting the AC voltage to a predetermined DC voltage, and outputting the converted voltage to the auxiliary machine 55.

  As shown in FIG. 2, the inverter device 50 includes a DC / DC converter 50a, a DC / AC inverter 50b, a grid-connected inverter control device 50c, and an inverter power supply DC / DC converter 50d.

  The DC / DC converter (converter) 50a receives a DC voltage (for example, 40V) output from the fuel cell 24, converts it to a predetermined DC voltage (for example, 350V), and outputs it. The DC / DC converter 50a converts the direct current voltage input from the fuel cell 24 into a predetermined direct current voltage and outputs it to the auxiliary device 55 for operating the fuel cell system. The DC / DC converter 50a is preferably an insulation type that is configured with, for example, a transformer as a component, and the input side and the output side are insulated.

  The DC / AC inverter (inverter) 50b receives the DC voltage (for example, 350V) output from the DC / DC converter 50a, converts it to an AC voltage (for example, 200V), outputs it to the power line 52, and from the power line 52 The input AC voltage (for example, 200 V) is converted into a predetermined DC voltage (for example, 350 V) and output to the auxiliary machine 55 via the auxiliary machine power supply board 54. Thus, the DC / AC inverter 50b has a function of converting direct current into alternating current and a function of converting alternating current into direct current.

  The DC / AC inverter 50 b includes a power measuring device 50 e that converts the power input from the fuel cell 24 and measures the output power output to the power line 52. The power measuring device 50e also converts auxiliary power consumption that is converted from power input from the system power supply 51 via the power supply line 52 and output to the auxiliary equipment 55 as power consumption when the fuel cell system is started and / or stopped. Measure. In the present embodiment, the DC / AC inverter 50b is composed of one device having both a function of converting direct current to alternating current and a function of converting alternating current to direct current. You may make it comprise with an apparatus. In this case, it is desirable that the power measuring device 50e is provided in advance in different devices.

  The grid interconnection inverter control device 50c controls the driving of the DC / DC converter 50a and the DC / AC inverter 50b, and on / off (communication / cutoff) of the first connector 50g and the second connector 50h. The grid-connected inverter control device 50c is connected to the control device 60 so as to be able to communicate with each other. In accordance with instructions from the control device 60, the DC / DC converter 50a, the drive of the DC / AC inverter 50b, the first connector 50g, The second connector 50h is controlled to be turned on / off (communication / blocking).

  The grid interconnection inverter control device 50c is connected to a power measurement device 50e, and receives a detection signal (power measurement value) from the power measurement device 50e. The grid interconnection inverter control device 50 c transmits the power measurement value to the control device 60. The control device 60 calculates power consumption during start-up and stop control based on the measured power value during start-up and stop control.

  The inverter power supply DC / DC converter 50d receives the DC voltage from the DC / DC converter 50a, the DC / AC inverter 50b, or the rectifier circuit 50f, converts the DC voltage into a predetermined DC voltage, and the DC / DC converter 50a and the DC / DC converter 50d. The power supply voltage (drive voltage) is supplied to the AC inverter 50b and the grid-connected inverter control device 50c.

  The rectifier circuit 50f is provided in parallel with the DC / AC inverter 50b between the power line 52 and the auxiliary machine 55, and can rectify the AC voltage from the power line 52 and convert it to a DC voltage and supply it to the auxiliary machine 55. It is a thing. For example, the rectifier circuit 50f includes four diodes that are rectifier elements, and includes a diode bridge circuit. It may be combined with a transformer, or may be combined with a resistor, a capacitor, a coil or the like for smoothing.

  The auxiliary machine power supply board 54 is connected to the DC / DC converter 50a, the DC / AC inverter 50b, and the rectifier circuit 50f, and inputs a DC voltage from the DC / DC converter 50a, the DC / AC inverter 50b, or the rectifier circuit 50f. Then, it is converted into a predetermined DC voltage (for example, 24V) and supplied to the auxiliary machine 55 as a power supply voltage. The auxiliary machine power supply board 54 is controlled by a command from the control device 60.

  Further, the fuel cell system includes a first connector 50g provided between the fuel cell 24 and the DC / DC converter 50a, and a second connector provided between the DC / AC inverter 50b and the power supply line 52. 50h is further provided.

  The first connector 50g communicates / cuts off (ON / OFF) the fuel cell 24 and the DC / DC converter 50a, is connected to the grid-connected inverter control device 50c, and is ON / OFF controlled by the instruction. Is. The second connector 50h is for connecting / disconnecting (ON / OFF) the DC / AC inverter 50b and the power supply line 52, and is connected to the grid-connected inverter control device 50c and controlled to be turned ON / OFF by the instruction. It is.

  The power supply line 52 is provided with a power measuring device 52a that detects input / output of power to the system power supply 51 and the amount of power, and the detection result is output to the system interconnection inverter control device 50c. The grid interconnection inverter control device 50 c transmits the power measurement value to the control device 60. The power measurement value may be output to the control device 60.

  In addition, the fuel cell system includes a unique breaker 52b. The breaker 52 b is provided on a power supply line that connects the power supply line 52 and the inverter device 50. When the breaker 52b uses a certain amount of power or an abnormal current flows, the breaker 52b automatically shuts off the circuit and prohibits power from being supplied from the breaker 52b to the inside of the system. Even at the time of this interruption, electric power is supplied to the input end 52b1 of the breaker 52b. Since the input end 52b1 may leak if it is submerged, the input end 52b1 is a potential leakage portion.

  The system power supply (or commercial power supply) 51 supplies power to the power load 53 via a power supply line 52 connected to the system power supply 51. The fuel cell 24 is connected to a power supply line 52 via an inverter device 50. The power load 53 is a load driven by an AC power supply, and is an electrical appliance such as a dryer, a refrigerator, or a television. The auxiliary machine 55 includes motor-driven pumps 41 a and 42 b for supplying reforming raw material, water, and air to the fuel cell module 20, a ventilation air blower 15, and the like. That is, the auxiliary machine 55 is for starting, generating, and stopping the fuel cell system. The auxiliary machine 55 is driven by a DC voltage, and the drive voltage is supplied from the auxiliary power supply board 18.

  Further, a portion in the above-described fuel cell system (that is, in the casing 11) that may be leaked by being submerged in the alternating current system 56 from the system power supply 51 to the inverter device 50 is a leakable portion. . For example, the input end 52b1 of the breaker 52b is a site where electric leakage is possible. In addition, the inverter device 50 is a potential leakage portion, and in particular, the DC / AC inverter 50b, the power measurement device 50e, the rectifier circuit 50f, and the second connector 50h (particularly the lower ends of each) are potential leakage portions.

  In the fuel cell system of the present embodiment, this leakage potential portion is installed above the conductivity meter 72a.

  Further, the fuel cell system includes a control device 60. The control device 60 is connected to the conductivity meter 72a, the pumps 32a, 41a, and 42b, the blowers 15 and 44a, the grid-connected inverter control device 50c, the radiator 32b, and the drain valve 34a (see FIG. 3). reference). The control device 60 includes a microcomputer (not shown), and the microcomputer includes an input / output interface, a CPU, a RAM, and a ROM (all not shown) connected via a bus. The CPU is operating the fuel cell system. The RAM temporarily stores variables necessary for executing the program, and the ROM stores the program.

  This control device 60 is based on the output power from the inverter device 50 detected by the power measuring device 50c and the power inputted to and outputted from the system power source 51 detected by the power measuring device 52a in a state where the fuel cell 24 can generate power. The power consumption (power generation load) consumed by the external power load 53 is calculated. For example, the sum of the output power from the inverter device 50 and the power input to and output from the system power supply 51 is calculated as the power consumption. The control device 60 controls the supply amount of the raw material, water, etc. supplied to the fuel cell module 20 so that the generated power of the fuel cell 24 becomes the calculated power consumption. When the power consumption exceeds the maximum generated power of the fuel cell 24, the fuel cell 24 is operated with the maximum generated power (that is, the power generation load is the maximum generated power).

  The control device 60 performs overall control of the fuel cell system in a centralized manner, and controls the fuel cell 24, the drive of the auxiliary device 55, and the drive of the inverter device 50. Or control the auxiliary power supply board 54. Since the control device 60 is connected to the DC / DC converter 50a, the DC / AC inverter 50b, and the rectifier circuit 50f, the control device 60 can be operated during standby (starting (starting control), generating power, However, the voltage is always supplied. The start time is from when a start command is issued until power generation is started, and the stop control is between the stop command is issued and the system is stopped. The standby state is a power generation stop state of the fuel cell system, and is a state waiting for a power generation instruction (such as turning on a start switch).

  The conductivity in the fuel cell system described above will be described below. When the deionizer 14 is normal, the conductivity of pure water is 1 to 10 μS / cm, and when the deionized water is normal, the conductivity is 2 to 20 μS / cm, and tap water (stored water, water supply) The conductivity is 100 to 300 μS / cm, and the conductivity is 100 to 300 μS / cm or more when submerged (rain water or muddy water).

  And in the normal case (when water shortage does not occur), the conductivity of the overflow water of the pure water tank 13 is 1 to 10 μS / cm, and the outlet side of the pure water device 14 (water after purification) The conductivity of the overflow water is 1 to 10 μS / cm, and the conductivity of the overflow water on the inlet side of the pure water device 14 (water before pure water purification) is 1 to 20 μS / cm (depending on the mixing ratio of the condensed water). change). In addition, there is a type in which the deionizer 14 has only an outlet side. That is, the deionizer 14 is a type in which there is no return channel and is a simple cylindrical container, and the condensed water supply pipe 46 extends to the lower part in the deionizer 14. Further, the deionizer 14 is a type in which there is no return channel and is a simple cylindrical container, and the condensed water supply pipe 46 is connected to the lower part of the deionizer 14. In either case, the condensed water flowing out from the condensed water supply pipe 46 flows upward from the lower part of the pure water device 14.

Next, the case where it is not normal will be described. The conductivity in case of water shortage is 0 μS / cm. The conductivity in the case of submergence is 100 to 300 μS / cm or more (if a conductivity meter is provided in the water conduit, it is affected by pure water but does not change greatly).
When the drain valve 34a is open, the conductivity is 100 to 300 μS / cm.

  When the water supply valve 14c is open, the heat medium leaks into the condenser 33 and flows into the pure water device 14, and if the pure water material is normal, the overflow water of the pure water tank 14 outlet side and the pure water tank 13 The conductivity of the water is 1 to 20 μS / cm, and the conductivity of the overflow water at the inlet side of the deionizer 14 is 30 to 250 μS / cm. On the other hand, if the pure water material has a life, the conductivity of the overflow water in the pure water 14 outlet side and the pure water tank 14 is 100 to 300 μS / cm, and the conductivity of water leakage from the water reservoir 16 is 1 to 10 μS. / Cm.

  The electrical conductivity in the case of leaking water from the condenser 33 only with condensed water is 2 to 20 μS / cm, and the electrical conductivity when the heat medium leaks into the condenser 33 is 100 to 300 μS / cm. Further, when the pure water material has a life, the initial conductivity is 1 to 20 μS / cm, and the conductivity gradually increases. Moreover, the electrical conductivity at the time of leaking from the hot water storage pipe or the water supply pipe is 100 to 300 μS / cm.

  The present invention is based on the premise that the generated water (condensed water) is larger than the water used (water supplied to the fuel cell module 20 (reformed water)), and the water remains. Therefore, as described above, in a normal state, the conductivity meter is 1 to 20 μS / cm, and the water overflowing from the outlet side of the water tank or the deionizer is 1 to 10 μS / cm, overflowing from the inlet side of the deionizer. The water that exits exhibits a conductivity of 1-20 μS / cm. When water shortage occurs, water does not overflow from the water reservoir, so the conductivity becomes 0 μS / cm, and water shortage can be detected.

  Next, the operation of the fuel cell system described above will be described with reference to FIG. When a start switch (not shown) is turned on, the control device 60 executes a program corresponding to the flowchart shown in FIG. 4 every predetermined short time (for example, 10 milliseconds). The control device 60 reads the conductivity from the conductivity meter 72a provided in the drain pipe 72 (step 102).

  When the conductivity value is greater than the second predetermined value and less than the first predetermined value and the instruction to the hot water valve 34a is closed (when the hot water valve is closed), the control device 60 In steps 104, 106, and 108, “YES”, “closed”, and “YES” are determined, and in step 110, steady operation (or start-up operation) is performed (continued).

  The first predetermined value is a reference for stopping the system upon detecting tap water or submergence, and is a predetermined value of 30 to 80 μS / cm (micro Siemens / centimeter), and is set to 50 μS / cm, for example. When the deionizer 14 is not deteriorated, the conductivity of pure water treated with the deionizer 14 is 1 to 10 μS / cm, and the conductivity of general tap water is 100 to 300 μS / cm. The conductivity of mud when the fuel cell is flooded due to cm, flood, etc. is 100 to 300 μS / cm or more, so the first predetermined value is set between the conductivity of pure water and the conductivity during flooding Has been. In addition, the electrical conductivity in the case of normal condensed water is 2 to 20 μS / cm.

  The second predetermined value is a reference for detecting water shortage, and is a predetermined value of 0.2 to 0.8 μS / cm. The second predetermined value is set to a value smaller than the first predetermined value, and is set to 0.5 μS / cm, for example. When drainage is not flowing through the drain pipe 72, the conductivity meter 72a measures the electrical conductivity of the air, so the conductivity meter 72a shows approximately 0 μS / cm. Therefore, the second predetermined value is set to a value between the electrical conductivity of air (0 μS / cm) and the electrical conductivity of pure water treated with the pure water device 14 (1 to 10 μS / cm). .

  In step 104, it is determined whether or not the conductivity value measured in step 102 is less than a first predetermined value. In step 106, it is determined whether the control instruction from the control device 60 to the hot water valve 34a is an opening instruction or a closing instruction. In step 108, it is determined whether or not the conductivity value measured in step 102 is greater than a second predetermined value.

  When the conductivity value is equal to or lower than the second predetermined value, the instruction to the drain valve 34a is closed, and the state where the conductivity value is equal to or lower than the second predetermined value does not continue for the first predetermined time or longer. In this case, the control device 60 determines “YES”, “closed”, “NO”, “NO” in steps 104, 106, 108, and 112, and performs a steady operation (or start-up operation) in step 110. In step 112, it is determined whether or not the state where the conductivity value is equal to or less than the second predetermined value continues for the first predetermined time or more. The first predetermined time is a time determined from the capacity of the pure water tank 13. When it is equal to or less than the second predetermined value, the amount of condensed water is insufficient with respect to the water used in the fuel cell 24, and the amount of water in the water tank 13 decreases when water is continuously used. Even if the amount of water in the water tank 13 decreases for the first predetermined time, it is set within a time during which operation can be continued. For example, the first predetermined time is set to 10 minutes. If the amount of water required when the condensed water is insufficient (for example, 100 cc) is set as the water tank capacity, the time within 10 minutes (for example, 5 minutes) is set.

  When the conductivity value is equal to or lower than the second predetermined value, the instruction to the drain valve 34a is closed, and the state where the conductivity value is equal to or lower than the second predetermined value continues for the first predetermined time or longer. In this case, the control device 60 determines “YES”, “closed”, “NO”, “YES” in steps 104, 106, 108, and 112, and determines that the water supplied to the fuel cell module 20 is insufficient. In 114, control to increase the recovered water (recovered water increase control) is performed.

  Specifically, the control unit 60 opens the drain valve 34a and drains the hot water heated by the first heat exchanger 33, so that the low temperature hot water is discharged from the hot water tank 31. The fuel cell system is controlled so that the amount of water supplied to the first heat exchanger 33 and supplied to the fuel cell module 20 increases. The recovered water increase control stop is performed by the control device 60 closing the drain valve 34a. Further, in the other recovered water increase control, the hot water stored in the first heat exchanger 33 may be cooled by driving the radiator 32b. Further, the power generation amount of the fuel cell 24 may be reduced. By reducing the amount of power generation, the heat load can be reduced to lower the cooling temperature of the hot water stored (heat dissipated by the radiator 32b).

  The recovered water increase control is continuously performed until the second predetermined time elapses. If the conductivity value does not become larger than the second predetermined value even if the recovered water increase control is performed continuously for the second predetermined time or longer, the control device 60 determines “NO” or “YES” in steps 116 and 115. And warn (step 118) and stop the system (step 120).

  The determination process in step 115 is the same as the determination process in step 108. In step 116, it is determined whether or not a second predetermined time has elapsed since the recovery water increase control was started. If the determination is “NO” in step 116, control device 60 returns the program to step 115, and if the determination is “YES”, control device 60 advances the program to step 118.

  If the conductivity value becomes larger than the second predetermined value before the second predetermined time has elapsed (determined as “YES” in step 115), it is determined that a predetermined amount or more of water can be collected, The control device 60 ends the current process in this flowchart. Thereafter, in the next process, since the conductivity value is larger than the second predetermined value, the control device 60 determines “YES” in Step 108, stops the recovered water increase control, and performs a steady operation (or start-up operation). (Step 110). In the second predetermined time, if the amount of condensed water generated does not increase even when the recovered water increase control is started (when the conductivity value does not become larger than the second predetermined value), the amount of recovered water generated is insufficiently increased. It is set to an appropriate time for determining. For example, it is set to 5 minutes, which is the time when the pure water tank 13 is equal to or higher than the predetermined water level when normal water increase control is performed.

  In step 118, the control device 60 issues a warning to stop before stopping the system. This warning is performed by sound, image, lighting, or the like. In step 120, the control device 60 first shuts off the second connector 50h (opens it) and then stops driving the raw material pump 42b and the reforming water pump 41a to stop the power generation of the fuel cell 24. The hot water circulating pump 32a and the blowers 15 and 44a are stopped, and then the first connector 50g is shut off (opened). Thereafter, the grid interconnection inverter control device 50c stops the operation of the DC / DC converter 50a, the DC / AC inverter 50b, and the inverter power supply DC / DC converter 50d.

  When the conductivity value is less than the first predetermined value and the opening instruction is made to the drain valve 34a, the control device 60 determines “YES” or “open” in steps 104 and 106. In step 124, it is determined that the hot water discharge valve 34a has failed (not opened), a warning is given that the hot water discharge valve 34a has not opened (step 118), and the system is stopped (step 120).

  When the conductivity value is equal to or higher than the first predetermined value and the opening instruction is given to the drainage valve 34a (when the drainage valve opening instruction is given), the control device 60 performs steps 104 and 122. “NO” and “open” are determined, and in step 110, steady operation (or start-up operation) is performed.

  When the conductivity value is equal to or higher than the first predetermined value and the close instruction is given to the drain valve 34a, the control device 60 determines “NO” or “closed” in steps 104 and 122. In step 124, it is determined that the hot water discharge valve 34a is not closed, a stored hot water leak, submersion, or deterioration of the fuel cell 24, and a warning is given to that effect (step 118), and the system is stopped. (Step 120).

  According to the operation of the fuel cell system described above, the fuel cell system can be operated by efficiently using water (condensed water) recovered in the system for water (reformed water) supplied to the fuel cell module 20. is there.

  In this fuel cell system, reforming raw material, cathode air, and reforming water are supplied to the fuel cell module 20, and the power generated by the fuel cell 24 is supplied to the external load power 53 via the inverter device 50. Supplied. The combustion exhaust gas discharged from the fuel cell module 20 is heat-exchanged with the hot water in the first heat exchanger 33, the heat of the combustion exhaust gas is recovered as hot water, and the water vapor in the combustion exhaust gas is condensed. Condensed water flows through the deionizer 14 by its own weight and is collected into a reformed water tank (pure water tank) 13.

  In this fuel cell system, it is known from experiments that the water balance (= recovered water flow rate−reformed water flow rate) is as shown in FIG. Both the recovered water flow rate and the required reforming water flow rate are flow rates per unit time (in this embodiment, minutes). At the rated load (maximum power generation amount), when the first heat exchanger outlet temperature of the combustion exhaust gas temperature (the temperature of the hot water stored in the first heat exchanger 33) is higher than about 45 ° C., the recovered water flow rate is the reformed water. Since it is smaller than the required flow rate, the required flow rate for the reforming water is insufficient. When the temperature is lower than about 45 ° C., the recovered water flow rate is larger than the required flow rate of the reforming water, so that there is a surplus with respect to the flow rate required for the reforming water. In addition, the lower the first heat exchanger outlet temperature of the combustion exhaust gas temperature, the larger the water balance.

  At the rated 50% load (50% of the maximum power generation), when the outlet temperature of the first heat exchanger of the combustion exhaust gas temperature is higher than about 46 ° C, the recovered water flow rate is smaller than the required reforming water flow rate. Insufficient flow rate for water. When the temperature is lower than about 46 ° C., the recovered water flow rate is larger than the required flow rate of the reforming water, so that there is a surplus with respect to the flow rate required for the reforming water. Compared to the rated case, the water balance is almost halved.

  At the rated 25% load (25% of the maximum power generation amount), when the outlet temperature of the first heat exchanger of the combustion exhaust gas temperature is higher than about 46 ° C, the recovered water flow rate is smaller than the required reforming water flow rate. Insufficient flow rate for water. When the temperature is lower than about 46 ° C., the recovered water flow rate is larger than the required flow rate of the reforming water, so that there is a surplus with respect to the flow rate required for the reforming water. The water balance is smaller than when the rating is 50%.

  Thus, the amount of condensed water changes by the saturated water vapor pressure in combustion exhaust gas changing with combustion exhaust gas temperature (1st heat exchanger exit temperature of combustion exhaust gas temperature). The lower the combustion exhaust gas temperature, the higher the recovered water flow rate. If the combustion exhaust gas temperature is equal to or lower than the temperature at which the water balance becomes 0, surplus water is generated with respect to the required flow rate of reforming water and passes through the overflow lines 14a and 13b. Then, surplus water flows through the exhaust pipe 72. At this time, since the conductivity meter 72a detects the conductivity of the condensed water (recovered water), the value is 1 to 10 μS / cm.

  On the other hand, the hot water is sent from the lower part of the hot water tank 31 by the reforming water pump 32 a, and the hot water recovered from the sensible heat and latent heat in the combustion exhaust gas is recovered by the first heat exchanger 33 to the upper part of the hot water tank 31. . A hot water discharge pipe 34 is branched from the first heat exchanger 33 of the hot water circulation line 32, and drained into the drain pipe 72 by opening the hot water discharge valve 34a. When the inside of the hot water storage tank 31 is full of hot water and the inflow temperature to the first heat exchanger 33 is high and the combustion exhaust gas cannot be cooled to the specified temperature and the water becomes insufficient, the hot water valve 34a is opened and the hot water is Then, cold water is supplied from the city water line connected to the hot water storage tank 31 to the hot water storage tank 31 so as to improve the cooling capacity and the water self-sustainability in the first heat exchanger 33.

  At this time, the conductivity meter 72a detects the conductivity of the atmosphere, and the conductivity value is equal to or less than the second predetermined value (0 μS / cm). Therefore, the shortage of recovered water can be detected, and open control of the hot water valve 34a (recovered water increase control) is performed to achieve water independence. In spite of this control, if the conductivity meter value does not return to 1 to 10 μS / cm even after the second predetermined time has elapsed, the system is stopped as an abnormality.

  In the above-described embodiment, instead of providing the overflow line 13 b in the pure water tank 13, or in addition to providing the overflow line 13 b, an overflow line (second water conduit) 14 a may be provided in the pure water device 14. The upper end of the overflow line 14 a is connected to the upper part of the deionizer 14. The connection position of the overflow line 14 a is higher than the connection position of the pipe 47. The lower end of the overflow line 14 a extends downward and extends to a position above the water receiving member 71 of the drainage device 70. The condensed water overflowed from the deionizer 14 is led to the drainage device 70 through the overflow line 14a. The overflow line 14 a is a water conduit 17 that is provided in the pure water device 14 that is the water reservoir 16 and guides the water overflowing from the pure water device 14 to the water receiving member 71.

  At this time, it is desirable that the water receiving member 71 receives water overflowing from the deionizer 14 provided in the housing 11. Immediately above the opening 71a of the water receiving member 71, the lower end of the overflow line 14a is disposed. Thereby, the water receiving member 71 can reliably receive the water overflowing from the deionizer 14 via the overflow line 14a. The water receiving member 71 is disposed at least below the connection position of the overflow line 14a of the deionizer 14 (the overflow port of the deionizer 14).

  The overflow line 14a is not permanently installed, and is shown by a broken line. Moreover, although the power supply line which connects the fuel cell 24 and the inverter apparatus 50, the power supply line 52, and the power supply line which connects the power supply line 52 and the inverter apparatus 50 are installed permanently, in order to display a power supply line, it is a broken line. Show.

  As is clear from the above description, in the present embodiment, the drainage device 70 converts the water vapor in the gas containing gas (combustion exhaust gas) circulating in the fuel cell system into a liquid heat medium (hot water storage water). From the water reservoir 16 that stores the condensed water supplied from the condenser (first heat exchanger 33) that generates condensed water (condensed water is supplied to the fuel cell module 20 as water) by condensing with the heat exchange. Drain overflowing water. The conductivity meter 72a is provided in the drainage device 70 and detects the conductivity of the drainage.

  As a result, firstly, during the start-up operation or power generation operation of the fuel cell system, when water does not overflow from the pure water tank 13 that is the reservoir 16, the heat medium leaks from the condenser 33, etc. If there is no abnormality, since the liquid is not discharged to the outside through the drainage device 70, the conductivity meter 72a shows almost zero. On the other hand, when water overflows from the pure water tank 13, the overflowed water is drained outside through the drainage device 70, and the conductivity of the drainage is detected by the conductivity meter 72a. In addition, the overflow of water from the pure water tank 13 indicates that the condensed water (recovered water) from the condenser 33 is more than the water (supply water) supplied to the fuel cell module. The fact that water does not overflow from the water tank 13 indicates that the recovered water flow rate matches or is less than the supply water flow rate (reformed water required flow rate). From the above, based on the detection result of the conductivity meter 72a provided in the drainage device 70, on the premise that there is no other abnormality such as leakage of the heat medium from the condenser 33, the condensed water ( It is possible to determine whether the amount of recovered water) is greater than the amount of water (supply water, reformed water) supplied to the fuel cell module 20, that is, whether the amount of water supplied to the fuel cell module 20 is insufficient. It becomes possible to judge.

  Second, when the fuel cell system is flooded, external water (for example, water during flooding: generally having a higher conductivity than the recovered water of the fuel cell system in a normal state) enters the drainage device 70 (backflow). ), The external water has high conductivity, so that the measured value of the conductivity meter 72a becomes relatively high. Therefore, by utilizing this fact, it is possible to reliably and accurately detect the external water entering the drainage device 70, that is, the flooding of the fuel cell system. The fuel cell system can be stopped early. As a result, the submergence further proceeds and the fuel cell system can be stopped before the leakable portion including the inverter device 59 disposed above the conductivity meter 72a is submerged. As a result, the leakable portion is submerged. Even in this case, it is possible to suppress leakage from the portion where leakage is possible.

  Thirdly, when the fuel cell 24 deteriorates or fails and the fine particles of the catalyst of the electrode of the fuel cell 24 are included in the combustion exhaust gas, the electrolyte in the condensed water condensed by the condenser 33 increases. The conductivity of the condensed water increases. Furthermore, when water having a relatively high conductivity (condensed water) overflows from the pure water tank 13, the overflowed water is drained outside through the drainage device 70, and the conductivity of the drainage is reduced. It is detected by the conductivity meter 72a. At this time, the conductivity meter 72a detects a conductivity higher than that of normal condensate, so that the heat medium leaks from the condenser 33 based on the detection result of the conductivity meter 72a provided in the drainage device 70. It is possible to determine the deterioration or failure of the fuel cell 24 on the assumption that there is no abnormality. When it is determined that the fuel cell 24 has deteriorated or failed, the fuel cell system can be stopped.

  Fourthly, the partition between the gas line in the condenser 33 and the heat medium line (hot water circulation line 32) is broken, and the heat medium (hot water) flows into the condensed water line (condensate supply pipe 46). With respect to the fuel cell system, the conductivity of the overflowed water is detected by the conductivity meter 72a higher than that of normal condensed water, so that the fuel cell system can be stopped based on the detection result of the conductivity meter 72a provided in the drainage device 70. it can. Thereby, it is possible to prevent deterioration and failure caused by sending water having high conductivity to the fuel cell module 20.

  In addition, by using one conductivity meter 13a, it is possible to ensure the above-mentioned water independence, accurately detect flooding, and accurately detect fuel cell deterioration without incurring an increase in cost.

  The fuel cell module 20, the condenser 33, the water reservoir 16, and the drainage device 70 are disposed in the housing 11, and the drainage device 70 includes a water receiving member 71 that receives at least water overflowing from the water reservoir 16; A drain pipe 72 for discharging the received water from the water receiving member 71 to the outside of the housing 11 is provided. Thereby, in the fuel cell system in which the fuel cell module 20, the condenser 33, the water reservoir 16 and the drainage device 70 are disposed in the housing 11, the same operations and effects as described above can be obtained.

  In addition, since it further includes an overflow line (first water conduit) 13b that is a water conduit 17 that is provided in the pure water tank 13 that is the water reservoir 16 and that guides the water overflowing from the pure water tank 13 to the water receiving member 71. The water overflowing from the pure water tank 13 can be reliably guided to the drainage device 70, and as a result, it can be determined whether the water supplied to the fuel cell module 20 is insufficient.

  Further, the water purifier 14 is further provided with an overflow line (second water conduit) 14 a that is provided in the water purifier 14 that is provided in the water purifier 14 and that guides the water overflowing from the water purifier 14 to the water receiving member 71. As a result, the water overflowing from the deionizer 14 can be reliably guided to the drainage device 70, and as a result, it can be determined whether the water supplied to the fuel cell module 20 is insufficient.

  In addition, the water reservoir 16 includes a deionizer 14 that purifies the condensed water supplied from the condenser 33, and a water tank 13 that stores the pure water supplied from the deionizer 14. A first water conduit 13b that guides water overflowing from the water tank 13 to the water receiving member, and a second water conduit 14a that guides water overflowing from the water purifier 14 provided to the water purifier 14 to the water receiving member. At least one of them was provided as a water conduit 17. Thereby, the water overflowing from the water tank 13 can be reliably guided to the drainage device 70 by the first water conduit 13b, and the water overflowing from the pure water device 14 is reliably drained by the second water conduit 14a. Therefore, it is possible to determine whether the water supplied to the fuel cell module 20 is insufficient.

  Moreover, hot water storage water is stored, hot hot water is supplied from the top, and low temperature replenishment water is replenished from the lower portion of the hot water storage tank 31, and one end is connected to the lower part of the hot water storage tank 31 and the upper part of the hot water storage tank 31 is connected. The other end is connected to the condenser 33, and a hot water circulating line 32 for supplying hot water to the condenser 33 as a heat medium, a hot water inlet of the hot water tank 31, and a hot water outlet of the condenser 33 are provided. The hot water pipe 34 is connected to a hot water circulation line 32 between the two and is connected to the drain 33 to drain the hot water after heat exchange with the condenser 33, and the hot water provided to the hot water pipe 34 opens and closes the hot water pipe 34. And a valve 34a. Thus, when the hot water discharge valve 34 a is opened, the heat medium heated by the condenser 33 is discharged outside through the hot water pipe 34 without returning to the hot water storage tank 31. Along with this, low temperature makeup water is supplied from the lower part of the hot water tank 31, and the low temperature makeup water is supplied to the condenser 33. In the condenser 33, the amount of condensed water generated is increased by the low-temperature heat medium. Therefore, when the condensed water (recovered water) from the condenser 33 is less than the water (supply water) supplied to the fuel cell module 20, that is, when the water supplied to the fuel cell module 20 is insufficient, the drain valve By opening 34a, the supply amount of condensed water can be increased, and the shortage of water supplied to the fuel cell module 20 can be solved.

  The control device 60 further controls the operation of the fuel cell system based on the conductivity value measured by the conductivity meter 72a, and the control device 60 has a drainage conductivity value of the drainage device 70 equal to or higher than a first predetermined value. If this happens, the fuel cell system is stopped. As a result, the heat medium leaked from the heat medium flowing member such as the condenser 33 and the supply pipe for supplying the heat medium to the condenser 33, the fuel cell system was submerged, and the fuel cell 24 was deteriorated or failed. When this is detected, the fuel cell system can be stopped reliably.

  Further, the control device 60 further controls the operation of the fuel cell system based on the conductivity value measured by the conductivity meter 72a, and the control device 60 has a drainage conductivity value of the drainage device 70 equal to or less than a second predetermined value. In this case, it is determined that the water supplied to the fuel cell module 20 is insufficient, and the fuel cell system is controlled so that the water supplied to the fuel cell module 20 increases. Thereby, it can be determined reliably that the water supplied to the fuel cell module 20 is insufficient. Even when the hot water tank 31 is in a state of excessive heat, the hot water stored in the condenser 33 is drained by opening the hot water discharge valve 34 a and draining the hot water stored in the condenser 33. By supplying to 33, the condensate water collect | recovered can be increased and the shortage of the water supplied to the fuel cell module 20 can be eliminated reliably.

  Further, the control device 60 further controls the operation of the fuel cell system based on the conductivity value measured by the conductivity meter 72a, and the control device 60 discharges the waste water in spite of instructing to close the drain valve 34a. When the conductivity value of the drainage of the device 70 is equal to or greater than the third predetermined value, or the drainage conductivity value of the drainage device 70 is equal to or less than the fourth predetermined value in spite of the opening instruction to the drain valve 34a. If there is, stop the fuel cell system. Thereby, the abnormality of the hot water discharge valve 34a can be determined accurately, and the fuel cell system can be stopped appropriately. The third predetermined value is a reference for detecting an abnormality in the operation of closing the hot water valve. The third predetermined value is a predetermined value of 30 to 80 μS / cm, and is set to 60 μS / cm, for example. The third predetermined value may be the same as or different from the first predetermined value. The fourth predetermined value is a reference for detecting an abnormality in opening operation of the drain valve. The fourth predetermined value is a predetermined value of 30 to 80 μS / cm, and is set to 70 μS / cm, for example. The fourth predetermined value may be the same as or different from the first predetermined value or the third predetermined value.

  When the third predetermined value and the fourth predetermined value are the same as the first predetermined value, the above-described flowchart of FIG. 4 can be used. That is, in the case where the conductivity value of the drainage of the drainage device 70 is equal to or higher than the first predetermined value (third predetermined value) despite the close instruction to the hot water valve 34a, the control device 60 performs step 104. , 122 determines “NO” and “Y closed” and advances the program to step 124. When the conductivity value of the drainage of the drainage device 70 is equal to or lower than the first predetermined value (fourth predetermined value) despite the opening instruction to the hot water valve 34a, the control device 60 performs steps 104 and 122. And "YES" and "open" are determined, and the program proceeds to step 124. In addition, when the third predetermined value and the fourth predetermined value are different from the first predetermined value, the drainage conductivity value of the drainage device 70 is set to the third predetermined value in spite of instructing the drain valve 34a to close. In the case of the above, the control device 60 may perform the processing from step 124 onward. When the conductivity value of the drainage of the drainage device 70 is equal to or lower than the fourth predetermined value despite the opening instruction to the drain valve 34a, the control device 60 performs the processing from step 124 onward. That's fine.

  The deionizer 14 is further provided with a deionizer 14 that purifies the condensed water supplied from the condenser 33 and then supplies the deionized water tank 13 to the deionized water tank 13. It is configured to receive at least. Thereby, when the deionizer 14 is deteriorated, the electrolyte in the condensed water condensed by the condenser 33 is not removed by the deionizer 14, so that the conductivity of the condensed water supplied to the deionized water tank 13 is a large value. It becomes. Furthermore, when water having a relatively high conductivity (condensed water) overflows from the pure water tank 13, the overflowed water is drained outside through the drainage device 70, and the conductivity of the drainage is reduced. It is detected by the conductivity meter 72a. At this time, since the conductivity meter 72a detects higher conductivity than the condensed water purified by the normal deionizer 14, based on the detection result of the conductivity meter 72a provided in the drainage device 70, the condenser It is possible to determine the deterioration of the deionizer 14 on the assumption that there is no other abnormality such as leakage of the heat medium from 33. When it is determined that the deionizer 14 has deteriorated, the fuel cell system can be stopped.

  In the above-described embodiment, instead of the water receiving member 71, as shown in FIG. 6, the pure water tank 13 is disposed below the pure water tank 13 as the water reservoir 16 so as to cover the pure water. You may make it use the water receiving member 73 comprised so that the water which overflows from the tank 13 or leaks and falls may be used. The water receiving member 73 can reliably receive and drain the water that leaks or overflows from the pure water tank 13, and the conductivity of these liquids can be reliably detected.

  Further, the water receiving member 73 is disposed below the condenser 33 so as to cover the condenser 33, and is configured to receive a heat medium (hot water storage water) that leaks from the condenser 33 and falls. May be. As a result, the heat medium leaked from a member through which the heat medium flows, such as the condenser 33 and a supply pipe that supplies the heat medium to the condenser 33 (part of the hot water circulation line 32 disposed in the housing 11). In this case, the leaked heat medium is drained to the outside through the drainage device 70, and the conductivity of the drainage is detected by the conductivity meter 72a. Generally, the conductivity of the heat medium is larger than the conductivity of the condensed water condensed in the normal condenser 33. That is, when the conductivity meter 72a detects a conductivity higher than that of normal condensed water, the heat medium may have leaked from the condenser 33 or a member through which the heat medium flows, such as a supply pipe that supplies the heat medium to the condenser 33. It becomes possible to judge that there is. When it is determined that the heat medium has leaked, the fuel cell system can be stopped. In order to leak the heat medium from the condenser 33, it is assumed that the heat medium pipe in the condenser 33 is broken and the heat medium leaks from the heat medium pipe to the exhaust gas side.

  Further, the water receiving member 73 is disposed below the deionizer 14 serving as the water reservoir 16 so as to cover the deionizer 14 and receives water that overflows or leaks from the deionizer 14. It is configured as follows. Thereby, the water receiving member 73 can reliably receive and drain the water that leaks or overflows from the deionizer 14, and the conductivity of these liquids can be reliably detected. In order to leak the heat medium from the condenser 33, it is assumed that the heat medium pipe in the condenser 33 is broken and the heat medium leaks from the heat medium pipe to the exhaust gas side.

  Further, the water receiving member 73 described above is configured such that one water receiving member receives both the liquid leaked from the pure water tank 13, the pure water device 14, and the condenser 33 and the liquid from the overflow lines 13b and 14a. Although there are two water receiving members, a water receiving member that receives liquid leaked from the pure water tank 13, the pure water device 14, and the condenser 33 and a water receiving member that receives both liquid from the overflow lines 13b and 14a. It may be configured. In this case, either one may be configured to receive the other water, and the drainage pipe 72 may be provided on the other. Further, another water receiving member that receives water from the two water receiving members may be provided, and the drain pipe 72 may be provided on the water receiving member.

  In addition, the present invention can be applied to a system in which the above water self-sustained control is not performed. In the system, as shown in FIG. 7, external water such as tap water is supplied to a recovered water system (between the condenser 33 and the pure water tank 13). That is, the water supply pipe 14b is connected to the deionizer 14, and the tap water is supplied to the deionizer 14 through the water supply pipe 14b. A water supply valve 14 c is provided in the water supply pipe 14 b, and its opening / closing is controlled by a command from the control device 60. The pure water tank 13 is provided with a conductivity meter 13a that detects the conductivity of the liquid in the container (pure water in the present embodiment). The detection result of the conductivity meter 13 a is transmitted to the control device 60. The conductivity meter 13a is for detecting the deterioration of the deionizer 14 and the deterioration of the fuel cell 24 when the water self-sustained control is not performed.

  Further, the pure water tank 13 provided with a conductivity meter 13a for detecting the conductivity of the liquid in the container is submerged in the alternating current system 56 from the system power supply 51 to the inverter device 50 in the fuel cell system. It is installed below the potential leakage area where there is a possibility of leakage. As a result, when the fuel cell system is flooded, external water (for example, water at the time of flooding: generally having higher conductivity than the recovered water and tap water of the fuel cell system in a normal state) flows back through the overflow line 13b. If the water enters the pure water tank 13 by flowing from the upper part of the pure water tank 13 or the like, the conductivity of the external water is high, so the measured value of the conductivity meter 13a is the previous value (external water is Higher than the value of the liquid in the pure water tank 13a before launching). Therefore, by utilizing this fact, it is possible to reliably and accurately detect the external water entering the pure water tank 13, that is, the flooding of the fuel cell system. Thus, it becomes possible to stop the fuel cell system at an early stage (including stopping the power conversion device).

  Moreover, since the conductivity meter 72a is located below the conductivity meter 13a at the time of flooding, it can be detected earlier than the conductivity meter 13a. Further, it is possible to detect when the water supply valve 14c is out of order. Specifically, an open failure (open failure) can be detected regardless of the closing instruction. That is, when a large amount of tap water enters, the deionizer 14 deteriorates early, the conductivity in the deionized water tank 13 increases, and the conductivity rises above the first predetermined value, so that detection / stop is possible. It is. Furthermore, a closed failure (closed failure) can be detected regardless of the opening instruction. That is, it is possible to stop by detecting that water shortage is not solved even though water is being replenished, as in the mode of the hot water valve.

  The conductivity meter 72a may be provided in a portion of the water distribution pipe 72 that is outside the casing 11. Further, the drainage device 70 may be disposed outside the housing 11.

  The present invention can also be applied to a fuel cell system provided with a polymer electrolyte fuel cell. In this case, there are a reformed gas condenser and an off-gas condenser in addition to the combustion exhaust gas condenser. Only the reformed gas condenser and the off-gas condenser leave water (condensed water).

DESCRIPTION OF SYMBOLS 11 ... Case, 11a ... 1st exhaust port, 11b ... Air outlet port, 11c ... Air inlet port, 12 ... Partition member, 12a ... Air inlet port, 13 ... Pure water tank, 13a ... Conductivity meter, 13b ... Overflow Line (first water conduit), 14 ... pure water device, 14a ... overflow line (second water conduit), 15 ... air blower (ventilation means) for ventilation, 16 ... water reservoir, 17 ... water conduit, 20 ... fuel cell Module, 21 ... casing, 21a ... outlet, 22 ... evaporating part, 23 ... reforming part, 24 ... fuel cell, 24a ... cell, 24b ... fuel flow path, 24c ... air flow path, 25 ... manifold, 30 ... exhaust Heat recovery system, 31 ... Hot water tank, 32 ... Hot water circulation line, 32 ... Hot water circulation pump, 32a ... Hot water circulation pump, 32b ... Radiator, 32c ... Temperature sensor, 33 ... First heat exchanger (condenser), 4 ... Hot water pipe, 34a ... Hot water valve, 41 ... Feed water pipe, 41a ... Reformed water pump, 42 ... Reforming raw material supply pipe, 42a ... Desulfurizer, 42b ... Raw material pump, 50 ... Inverter device (power conversion) Device), 50a ... DC / DC converter, 50b ... DC / AC inverter, 50c ... system interconnection inverter control device, 50d ... power source DC / DC converter for inverter, 50e ... power measuring device, 50f ... rectifier circuit, 50g ... DESCRIPTION OF SYMBOLS 1 connector, 50h ... 2nd connector, 51 ... system | strain power supply, 52 ... power supply line, 52a ... power measuring device, 53 ... external power load, 54 ... power supply board for auxiliary machines, 55 ... auxiliary machine, 56 ... alternating current System, 60 ... control device, 70 ... drainage device, 71, 73 ... water receiving member, 72 ... drainage pipe, 72a ... conductivity meter, R1 ... first chamber, R2 ... second chamber.

Claims (10)

A fuel cell system comprising a fuel cell module comprising at least a fuel cell and supplied with water, fuel and oxidant gas,
A condenser for condensing water vapor in a gas containing moisture flowing in the fuel cell system by heat exchange with a liquid heat medium to generate condensed water;
A water reservoir for storing the condensed water supplied from the condenser;
Water supply means for supplying the condensed water stored in the water reservoir as the water to the fuel cell module;
A drainage device for discharging water overflowing from the water reservoir;
A fuel cell system comprising: a conductivity meter provided in the drainage device for detecting conductivity of the drainage.   The fuel cell module, the condenser, the water reservoir, and the drainage device according to claim 1, wherein the drainage device includes at least a water receiving member that receives at least water overflowing from the water reservoir, A fuel cell system comprising: a drain pipe for discharging the received water from the water receiving member to the outside of the housing.   3. The fuel cell system according to claim 2, further comprising a water guide pipe that is provided in the water reservoir and guides the water overflowing from the water reservoir to the water receiving member.   4. The fuel cell system according to claim 2, wherein the water receiving member is disposed below the water reservoir and receives water that leaks from the water reservoir and falls. .   5. The fuel cell system according to claim 2, wherein the water receiving member is configured to receive the heat medium that leaks and falls from the condenser. 6. The water reservoir according to claim 3, comprising: a deionizer that purifies condensed water supplied from the condenser; and a water tank that stores the pure water supplied from the deionizer.
A first water conduit provided in the water tank for guiding water overflowing from the water tank to the water receiving member, and a first conduit for guiding water overflowing from the pure water device provided in the pure water device to the water receiving member. A fuel cell system comprising at least one of the two water conduits as the water conduit. In any one of Claims 1 thru | or 6,
A hot water storage tank that stores hot water, supplies hot hot water from the top, and supplies low-temperature makeup water from the bottom by the reduced amount;
One end is connected to the lower part of the hot water tank, the other end is connected to the upper part of the hot water tank, the condenser is provided in the middle, and the hot water circulating line for supplying the hot water as the heat medium to the condenser;
A hot water pipe for draining hot water after being connected to the hot water circulation line between the hot water storage inlet of the hot water storage tank and the hot water outlet of the condenser and being heat-exchanged by the condenser to the drainage device;
A fuel cell system, further comprising a hot water valve provided in the hot water pipe and opening and closing the hot water pipe. The control device according to any one of claims 1 to 7, further comprising a control device that controls operation of the fuel cell system based on a conductivity value measured by the conductivity meter,
The said control apparatus stops the said fuel cell system, when the electrical conductivity value of the waste_water | drain of the said drainage apparatus becomes more than a 1st predetermined value, The fuel cell system characterized by the above-mentioned. The control device according to any one of claims 1 to 7, further comprising a control device that controls operation of the fuel cell system based on a conductivity value measured by the conductivity meter,
When the conductivity value of the drainage of the drainage device is equal to or less than a second predetermined value, the control device determines that the water supplied to the fuel cell module is insufficient, and the water supplied to the fuel cell module A fuel cell system, wherein the fuel cell system is controlled to increase. In Claim 7, further comprising a control device for controlling the operation of the fuel cell system based on the conductivity value measured by the conductivity meter,
The control device instructs the drainage valve to open when the conductivity value of the drainage of the drainage device is equal to or greater than the third predetermined value even though the drainage valve is instructed to close. Nevertheless, the fuel cell system is stopped when the conductivity value of the drainage of the drainage device is a fourth predetermined value or less.

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