JP2019057438A - Fuel cell system - Google Patents

Abstract

A fuel cell system capable of continuing a power generation operation without causing a decrease in power generation efficiency due to a shortage of reforming water. A fuel cell system (1) is provided between a heat exchanger (12) and a radiator (22b) of a hot water supply pipe (22e) and is separated from the circulating water supply amount and circulating water flowing in the heat exchanger (12) and reformed. A control device that detects a first temperature T1 of the circulating water that is provided between the three-way valve 22d and the three-way valve 22d and the radiator 22b and that passes through the radiator 22b. The first temperature sensor 22c that outputs to the water 16, the makeup water supply pipe 22f that supplies makeup water to the water purifier 14 from the three-way valve 22d, and the reformed water generated from the condensed water and makeup water by the water purifier 14 And a water level sensor 15 d that detects the water level stored in the reformed water tank 15 and outputs the detected water level to the control device 16. [Selection] Figure 1

Description

  The present invention relates to a fuel cell system.

  Conventionally, for example, a fuel cell device disclosed in Patent Document 1 below is known. In this conventional fuel cell device, the exhaust gas from the fuel cell and the water in the hot water storage tank are heat-exchanged by a heat exchanger, and condensed water generated by cooling the exhaust gas is collected in the condensed water tank and hot water is stored in the hot water storage tank. Are supposed to be stored. And when the temperature of the hot water supplied from the hot water storage tank to the heat exchanger is high, the hot water is cooled by the radiator of the circulation passage.

  Conventionally, for example, a fuel cell system disclosed in Patent Document 2 below is also known. In this conventional fuel cell system, the water level of the reformed water stored in the water reservoir is an abnormal level where it is difficult to pump to the reforming unit by the pump, and a normal level between the overflow level and the abnormal level, If it is between, the output of the fuel cell is reduced.

JP 2001-325882 A JP, 2006-177998, A

  In general, a fuel cell system is provided with a reforming section to which a mixed gas obtained by mixing reforming raw material and reformed water, which is made into steam, is provided and mixed by a steam reforming reaction that occurs inside the reforming section. The gas is reformed to generate reformed gas (fuel). Then, the generated reformed gas (fuel) is supplied to the fuel cell to generate power.

  By the way, in the said conventional fuel cell apparatus (fuel cell system), the condensed water condensed with the heat exchanger is collect | recovered as reformed water. In this case, by using the radiator to cool the hot water supplied from the hot water storage tank, it is possible to promote the generation of condensed water in the heat exchanger and improve the utilization efficiency of the reforming water. However, it is difficult to recover all the steam components in the exhaust gas, and when the reforming water stored in the reforming water tank is insufficient and the supply of steam to the reforming unit becomes impossible, the fuel The battery system needs to be stopped.

  On the other hand, in the conventional fuel cell system, when the level of the reformed water stored in the water reservoir (reformed water tank) decreases, the recovery amount of the reformed water is increased by limiting the output. Avoid stopping the fuel cell system. However, when the output is limited, there is a possibility that the power generation efficiency of the fuel cell system is lowered and the energy utilization efficiency is lowered.

  The present invention has been made to solve the above problems. That is, an object of the present invention is to provide a fuel cell system capable of continuing a power generation operation without causing a decrease in power generation efficiency due to a shortage of reforming water.

  In order to solve the above-mentioned problem, the invention of the fuel cell system according to claim 1 is directed to a fuel cell that generates power using fuel and an oxidant gas, and a fuel from a reforming raw material and water vapor obtained by evaporating the reforming water. A reforming unit that generates and supplies fuel to the fuel cell and a reforming material supply pipe connected to a reforming material supply source, and pumps the reforming material from the supply source to the reforming unit. Generated by burning reforming raw material supply device, reforming water tank for storing reforming water supplied to reforming section via reforming water supply pipe, and burning fuel off-gas and oxidant gas from fuel cell A condenser that generates heat by condensing water vapor contained in the combustion exhaust gas by exchanging heat between the combustion exhaust gas and the circulating water supplied from the hot water storage tank through the hot water supply pipe; The condensed water is provided in a condensed water supply pipe connecting the tank and the condenser, and the condensed water is purified and reformed water. A water purifier that supplies the reformed water tank, a radiator that is provided in the hot water supply pipe and cools the circulating water supplied from the hot water tank, and a controller that controls the power generation of the fuel cell in an integrated manner. A fuel cell system, which is provided between the condenser and the radiator of the hot water supply pipe, and supplies the circulating water supplied to the condenser side and the reformed water tank separated from the circulating water. The amount of makeup water supplied to the side of the circulating water is adjusted between a regulating valve that can be adjusted according to control by the control device, and a regulating valve of the hot water supply pipe and a radiator that is provided between the regulating valve and the radiator. A first temperature sensor that detects one temperature and outputs the first temperature to the control device; a replenishing water supply pipe that connects the regulating valve and the water purifier and supplies makeup water from the regulating valve to the water purifier; Generated from condensate and makeup water by water purifier A replenishing water adjusting unit that adjusts the supply of hot water from the hot water tank to the reforming water tank, including a water level sensor that detects the water level stored in the reforming water tank of quality water and outputs the water level to the control device The control device includes a preset first temperature of the circulating water detected by the first temperature sensor when the water level detected by the water level sensor is a preset makeup water supply start water level. When the temperature falls below a predetermined temperature, the supply amount of makeup water from the adjustment valve is increased from zero and makeup water is supplied to the reforming water tank through the makeup water supply pipe and the water purifier, and the water level sensor When the detected water level reaches a preset makeup water supply stop water level, the makeup water supply amount by the adjustment valve is returned to zero.

  According to this, when the water level of the reforming water tank becomes the makeup water supply start water level, that is, the control device may run out of water vapor (reforming water) supplied from the reforming water tank to the reforming unit. In the case where there is a property, the makeup water adjusting unit can be operated. When the makeup water adjustment unit is activated, the regulating valve separates makeup water from the circulating water supplied from the hot water tank and having the first temperature below the first predetermined temperature, and supplies the separated makeup water to the water purifier. Can be supplied. The water purifier can supply the reformed water obtained by purifying the separated makeup water to the reformed water tank. Thereby, during the power generation operation of the fuel cell system, a necessary and sufficient amount of reforming water can be always stored in the reforming water tank. As a result, a necessary and sufficient amount of reforming water (steam) can be supplied from the reforming water tank to the reforming unit, and the reforming unit generates fuel consumed by the fuel cell to generate power from the fuel cell. Can continue. Therefore, the power generation operation of the fuel cell system can be continued without causing a decrease in power generation efficiency due to the shortage of reforming water.

It is the schematic which shows the outline | summary of the fuel cell system which concerns on embodiment of this invention. It is a figure which shows the structure of the water level sensor of FIG. It is a flowchart which shows the makeup water supply control program performed by the control apparatus of FIG. It is the schematic which shows the outline | summary of the fuel cell system which concerns on the modification of embodiment. It is a flowchart which shows the makeup water supply control program which concerns on a modification and is performed by the control apparatus of FIG. It is the schematic which shows the outline | summary of the fuel cell system which concerns on the other modification of embodiment.

  Hereinafter, a fuel cell system according to an embodiment of the present invention will be described with reference to the drawings. In addition, in the following embodiment and each modification, the same code | symbol is attached | subjected to the part which is mutually the same or equivalent. Each figure used for explanation is a conceptual diagram, and the shape of each part may not necessarily be exact.

  The fuel cell system 1 includes a power generation unit 10 and a hot water tank 21 as shown in FIG. The power generation unit 10 includes a casing 10a, a fuel cell module 11, a heat exchanger 12, an inverter device 13, a water purifier 14, a reforming water tank 15, a control device 16, and a makeup water adjusting unit 70.

  The hot water tank 21 is a sealed and pressure resistant container. The temperature distribution in the hot water storage tank 21 is basically divided into two layers having different temperatures. The upper layer is a layer having a relatively high temperature (for example, 50 degrees or more), and the lower layer is a layer having a relatively low temperature (for example, 20 to 40 degrees). The upper and lower layers are at substantially the same temperature. The hot water storage tank 21 stores hot water, and is connected to a hot water circulation line 22 through which the hot water circulates (circulates in the direction of the arrow in the figure).

  The fuel cell module 11, the heat exchanger 12, the inverter device 13, the water purifier 14, the reforming water tank 15, the control device 16, the makeup water adjustment unit 70, and the hot water tank 21 are accommodated in the housing 10 a. The hot water storage tank 21 may be provided separately from the power generation unit 10, that is, outside the housing 10a.

  As will be described later, the fuel cell module 11 includes at least a fuel cell 34. The fuel cell module 11 is supplied with reforming raw material, reforming water, and air (cathode air) as an oxidant gas (cathode gas). Examples of the reforming raw material include gas fuel for reforming such as natural gas and LP gas, and liquid fuel for reforming such as kerosene, gasoline and methanol. In the present embodiment, the case where natural gas is used as the reforming raw material is illustrated. Specifically, the fuel cell module 11 is connected to a supply source Gs (for example, a gas supply pipe for city gas (natural gas)) and one end of a reforming raw material supply pipe 11a to which a reforming raw material is supplied. The other end is connected to the evaporation part 32 mentioned later. The reforming raw material supply pipe 11 a is provided with a raw material pump 11 a 1 (reforming raw material supply device) that pumps the reforming raw material to the evaporation section 32.

  Further, the fuel cell module 11 has one end connected to the reforming water tank 15 and the other end of the reforming water supply pipe 11 b to which the reforming water is supplied connected to the evaporation section 32. The reforming water supply pipe 11b is provided with a reforming water pump 11b2. Further, the fuel cell module 11 has one end connected to the cathode air blower 11c1 and the other end of the cathode air supply pipe 11c to which the cathode air is supplied. The cathode air blower 11 c 1 is an oxidizing gas supply device that supplies cathode air to the fuel cell 34.

  The heat exchanger 12 is supplied with combustion exhaust gas exhausted from the fuel cell module 11 (including exhaust heat from the reforming unit 33 and the fuel cell 34, which will be described later) and supplied with hot water from the hot water storage tank 21. In this heat exchanger, heat is exchanged between the combustion exhaust gas and the hot water. The heat exchanger 12 is also a condenser that performs heat exchange between the combustion exhaust gas and the stored hot water, and condenses water vapor contained in the combustion exhaust gas to generate condensed water. Here, the hot water is a heat medium (exhaust heat recovery water) that recovers the exhaust heat of the combustion exhaust gas through the heat exchanger 12.

  The heat exchanger 12 is connected (penetrated) with an exhaust pipe 11 d from the fuel cell module 11. A condensed water supply pipe 12 a connected to the reforming water tank 15 via a water purifier 14 is connected to the bottom of the heat exchanger 12.

  In the heat exchanger 12 configured as described above, the combustion exhaust gas from the fuel cell module 11 is introduced into the heat exchanger 12 through the exhaust pipe 11d, and heat exchange is performed with the circulating hot water. It is condensed and cooled. Thereafter, the combustion exhaust gas passes through the exhaust pipe 11d and is discharged from the combustion exhaust port 10d to the outside of the housing 10a. The condensed water condensed is dropped by its own weight and supplied from the water purifier 14 to the reformed water tank 15 through the condensed water supply pipe 12a. On the other hand, the hot water stored in the heat exchanger 12 is heated and flows out toward the hot water tank 21. The exhaust pipe 11 d is provided with a drain pipe 12 b that branches from the downstream side of the heat exchanger 12 and communicates with the water receiving member 15 b of the reforming water tank 15.

  Here, the heat exchanger 12, the hot water tank 21, and the hot water circulation line 22 described above constitute the exhaust heat recovery system 20. On the hot water circulation line 22, a hot water circulation pump 22 a, a radiator 22 b, a first temperature sensor 22 c, a three-way valve 22 d as an adjustment valve and the heat exchanger 12 are arranged in order from the lower end to the upper end of the hot water tank 21. ing. The exhaust heat recovery system 20 recovers and stores the exhaust heat of the fuel cell module 11 in hot water storage.

  The hot water circulation pump 22 a pumps hot water from the lower layer of the hot water tank 21 and supplies it to the heat exchanger 12 through the hot water supply pipe 22 e constituting the hot water circulation line 22. The radiator 22b is an air-cooled radiator having a motor and a fan, and is provided in the hot water storage water supply pipe 22e. The radiator 22b cools the hot water supplied from the hot water circulating pump 22a toward the heat exchanger 12 with its operation controlled by the control device 16 as will be described later.

  The first temperature sensor 22c is disposed between the radiator 22b and the heat exchanger 12, and the temperature T1 (hereinafter referred to as “first”) of circulating hot water as circulating water that passes through the radiator 22b and flows through the hot water supply pipe 22e. Temperature T1 ”) is detected and transmitted to the control device 16. The three-way valve 22d is disposed between the first temperature sensor 22c and the heat exchanger 12. The three-way valve 22d supplies the hot water cooled by the radiator 22b to the heat exchanger 12, and supplies makeup water separated from the hot water (circulated water) flowing through the hot water supply pipe 22e via the makeup water supply pipe 22f. The water purifier 14 and then the reformed water tank 15 are supplied.

  The three-way valve 22d has its valve opening adjusted by the control device 16, and the amount of hot water that has been cooled by the radiator 22b is supplied to the heat exchanger 12, in other words, reforming of the hot water that has been cooled by the radiator 22b. The amount of water supplied to the water tank 15 is adjusted. That is, the three-way valve 22d is a proportional valve capable of changing the valve opening, and the cooled hot water is used as the circulating water supply amount of the hot water (circulated water) supplied to the heat exchanger 12 and the reformed water. The ratio of the supplementary water supply amount supplied to the tank 15 can be adjusted.

  The make-up water supply pipe 22f supplies the make-up water supplied from the three-way valve 22d to the water purifier 14. The make-up water supply pipe 22f has a pressure loss portion 22f1 bent in a U-shape, and causes pressure drop in the make-up water flowing through the make-up water supply pipe 22f, thereby reducing the water pressure of the make-up water. . A water supply valve 22g for supplying makeup water to the water purifier 14 is provided in the makeup water supply pipe 22f. The water supply valve 22g is switched by the control device 16 between being open to allow the supply of makeup water to the water purifier 14 and being closed to block the supply of makeup water to the water purifier 14. In the present embodiment, the water supply valve 22g is switched to open when the three-way valve 22d supplies makeup water to the reforming water tank 15, and when the three-way valve 22d does not supply makeup water to the reforming water tank 15. It can be switched to closed. Here, the first temperature sensor 22c, the three-way valve 22d, the makeup water supply pipe 22f, the pressure loss portion 22f1, and the water supply valve 22g constitute a makeup water adjustment unit 70.

  The inverter device 13 receives DC power (voltage) output from the fuel cell 34, converts the DC power (voltage) into predetermined AC power (voltage), and is connected to an AC system power supply 17a and an external power load 17c (for example, an electrical appliance). Output to the power line 17b. The inverter device 13 is a power conversion device that converts DC power supplied from the fuel cell 34 into AC power. The external power load 17c is a load device to which power from the system power source 17a and power from the inverter device 13 are supplied. The inverter device 13 receives AC power (voltage) from the system power supply 17a via the power supply line 17b and converts it to predetermined DC power (voltage) to convert auxiliary equipment (each pump, blower, etc.) and control device. 16 is output.

  The water purifier 14 purifies condensed water and makeup water with ion exchange resin. The water purifier 14 communicates with the reforming water tank 15, and purified water and makeup water that have been purified are supplied to the reforming water tank 15.

  The reforming water tank 15 stores condensed water and makeup water supplied from the water purifier 14 as reforming water, and supplies the reforming water to the reforming unit 33 via the evaporation unit 32. When the supplied condensed water and makeup water overflow, the reforming water tank 15 is received by the water receiving member 15b through the overflow line 15a and drained from the drain pipe 15c to the outside of the housing 10a. The

  In the reformed water tank 15, as shown in FIG. 2, a water level sensor that detects the amount of reformed water stored in the reformed water tank 15 (water level: hereinafter also referred to as “tank water amount”). 15d is arranged. Here, the water level sensor 15 d is included in the makeup water adjusting unit 70. The water level sensor 15d is, for example, a float sensor, and is a sensor that converts the vertical amount of the float into a resistance value using a variable resistance (potentiometer) and displays the water level (residual water amount) by the vertical movement of the resistance value. . The water level sensor 15d detects the remaining water amount as a first management water level L1, a second management water level L2, a third management water level L3, and a fourth management water level L4. The first management water level L1 is a water level at which the reforming water tank 15 is full. The second control water level L2 is a makeup water supply stop water level that stops the supply of makeup water to be supplied as will be described later. The third control water level L3 is a makeup water supply start water level at which makeup water supply is started. The fourth control water level L4 is a level at which it becomes difficult to pump the reformed water by the reforming water pump 11b2.

  The control device 16 controls the operation of the fuel cell system 1 by driving the auxiliary devices including the radiator 22b, the three-way valve 22d, and the water supply valve 22g described above. The control device 16 has a microcomputer (not shown). The microcomputer includes an input / output interface, a CPU, a RAM, a ROM, and a timer (all not shown) connected to each other via a bus. The CPU performs the overall operation of the fuel cell system 1. The RAM temporarily stores variables necessary for executing various programs including a makeup water supply control program described later, and the ROM stores various programs including a makeup water supply control program described later.

  The fuel cell module 11 includes a casing 31, an evaporation unit 32, a reforming unit 33, and a fuel cell 34. The casing 31 is formed in a box shape with a heat insulating material. The evaporating unit 32 is heated by a combustion gas to be described later, evaporates the supplied reforming water to generate water vapor, and preheats the supplied reforming raw material. The evaporation section 32 mixes the steam generated in this way and the preheated reforming raw material and supplies the mixture to the reforming section 33.

  The other end of the reforming water supply pipe 11 b whose one end (lower end) is connected to the reforming water tank 15 is connected to the evaporation unit 32. The evaporating section 32 is connected to a reforming material supply pipe 11a having one end connected to the supply source Gs.

  The reforming unit 33 is heated by a combustion gas to be described later and supplied with heat necessary for the steam reforming reaction, so that the reforming unit 33 contains steam from the mixed gas (reforming raw material, steam) supplied from the evaporation unit 32. A reformed gas (anode gas) is generated and led out from the reformed gas delivery pipe 38. The reforming section 33 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 a gas containing hydrogen gas and carbon monoxide. (Steam reforming reaction). The reformed gas contains hydrogen, carbon monoxide, carbon dioxide, steam, unreformed natural gas (methane gas), and reformed water (steam) that has not been used for reforming. As described above, the reforming unit 33 generates reformed gas (fuel) from the reforming raw material (raw fuel) and the reformed water, and supplies the reformed gas to the fuel cell 34. The steam reforming reaction is an endothermic reaction.

  The fuel cell 34 is configured by stacking a fuel electrode, an air electrode (oxidant electrode), and a plurality of cells 34a made of an electrolyte interposed between the two electrodes. The fuel cell 34 of the present embodiment is a solid oxide fuel cell, and uses zirconium oxide, which is a kind of solid oxide, as an electrolyte. A reformed gas as a fuel, that is, hydrogen, carbon monoxide, methane gas, or the like is supplied to the fuel electrode of the fuel cell 34. The operating temperature is about 400-1000 ° C. It should be noted that the power generation amount below the rating is possible even at 400 ° C. or lower. The start of power generation is allowed at 600 ° C. Not only hydrogen but also natural gas and coal gas can be used directly as fuel. In this case, the reforming unit 33 can be omitted.

  On the fuel electrode side of the cell 34a, a fuel flow path 34b through which a reformed gas (anode gas) that is a fuel flows is formed. An air flow path 34c through which air (cathode air) that is an oxidant gas (cathode gas) flows is formed on the air electrode side of the cell 34a.

  The fuel cell 34 is provided on the manifold 35. A reformed gas (anode gas) from the reforming unit 33 is supplied to the manifold 35 through a reformed gas delivery pipe 38. The lower end (one end) of the fuel flow path 34b is connected to the fuel outlet of the manifold 35, and the reformed gas led out from the fuel outlet is introduced from the lower end and led out from the upper end. . The cathode air sent out by the cathode air blower 11c1 is supplied via the cathode air supply pipe 11c, introduced from the lower end of the air flow path 34c, and led out from the upper end.

  The cathode air blower 11c1 is driven by the electric motor 11c2, and the drive duty of the electric motor 11c2 is calculated by the control device 16. The flow rate sensor 11c3 provided on the downstream side of the cathode air blower 11c1 of the cathode air supply pipe 11c detects the cathode air flow rate discharged from the cathode air blower 11c1. The flow sensor 11c3 transmits the detection result to the control device 16.

In the fuel cell 34, power generation is performed by a reformed gas (anode gas) that is fuel supplied to the fuel electrode and an oxidant gas (cathode 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. Specifically, oxide ions (O ²⁻ ) generated at the air electrode permeate the electrolyte and react with hydrogen at the fuel electrode to generate electrical energy. The reformed gas and oxidant gas that have not been used for power generation are derived from the fuel flow path 34b and the air flow path 34c. The water (H ₂ O) generated in the fuel cell 34 by the reaction is sent to the reformed water tank 15 via the water purifier 14.
(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 (anode offgas as fuel offgas) that has not been used for power generation is led out from the fuel flow path 34b to the combustion section 36 (a space formed between the fuel cell 34 and the reforming section 33). Similarly, oxidant gas (air: cathode off gas) that has not been used for power generation is led out to the combustion section 36 from the air flow path 34c. In the combustion unit 36, the anode off gas is combusted by the cathode off gas, and the evaporation unit 32 and the reforming unit 33 are heated by the combustion gas (flame 37). Furthermore, the inside of the fuel cell module 11 is heated to the operating temperature.

  The combustion unit 36 is provided with a pair of ignition heaters 36a1 and 36a2 for igniting the anode off gas. Combustion exhaust gas generated in the combustion unit 36 reaches the heat exchanger 12 from the fuel cell module 11 through the exhaust pipe 11d together with water generated in the fuel cell 34 by an electrochemical reaction.

  When starting the fuel cell system 1, the control device 16 executes the warm-up mode prior to the power generation mode. In the warm air mode, the control device 16 drives the raw material pump 11a1 to supply the reforming raw material via the reforming raw material supply pipe 11a to the evaporation unit 32, the reforming unit 33, and the fuel cell 34 of the fuel cell module 11. To be supplied to the combustion section 36. The control device 16 also drives the cathode air blower 11c1, and supplies air (cathode gas), which is an oxidant gas, to the combustion unit 36 via the air electrode of the cell 34a of the fuel cell module 11 via the air flow path 34c. . When the ignition heaters 36a1 and 36a2 are ignited, the reforming raw material is combusted by air in the combustion section 36. The evaporation unit 32, the reforming unit 33, and the fuel cell 34 are heated by the combustion heat in the combustion unit 36. When the evaporation unit 32, the reforming unit 33, and the fuel cell 34 are heated to a predetermined temperature range, the control device 16 drives the reforming water pump 11b2 to start the reforming reaction in the reforming unit 33, End the warm-up mode and shift to the power generation mode.

  When the control device 16 drives the reforming water pump 11b2, the reforming water in the reforming water tank 15 is supplied to the evaporation unit 32 via the reforming water supply pipe 11b. The reformed water is heated by the evaporating unit 32 to become water vapor. The steam moves to the reforming unit 33 together with the reforming material supplied from the reforming material supply pipe 11a. In the reforming section 33, the reforming raw material is reformed with steam to become an anode gas (hydrogen-containing gas) that is a reformed gas containing steam (endothermic reaction). The anode gas is supplied to the fuel electrode of the cell 34a of the fuel cell 34 through the fuel flow path 34b. Further, the cathode air blower 11c1 is driven, and the cathode gas (air) is supplied to the electric electrode of the cell 34a through the air flow path 34c. Thereby, the fuel cell 34 (fuel cell module 11) generates electric power.

  In the warm air mode and the power generation mode, the high-temperature combustion exhaust gas generated in the fuel cell module 11 is discharged to the heat exchanger 12 having a condensing function through the exhaust pipe 11d together with the water generated in the fuel cell 34 by the electrochemical reaction. Is done. Since the water vapor contained in the high-temperature combustion exhaust gas is cooled by the heat exchanger 12, it is condensed and becomes condensed water, and the water generated in the fuel cell 34 by the electrochemical reaction is passed through the condensed water supply pipe 12a. To the reformed water tank 15.

  The housing 10a has an intake port 10b for sucking outside air, a ventilation exhaust port 10c for discharging air inside the housing 10a to the outside, and a combustion exhaust gas from the heat exchanger 12 to the outside. An exhaust port 10d for combustion exhaust gas is formed. A check valve 54 is provided at the intake port 10b. The check valve 54 allows the flow of air from the outside into the housing 10a, but restricts the flow in the reverse direction.

  A ventilation fan 55 is provided in the ventilation exhaust port 10c. The ventilation fan 55 sends out the air (ventilation exhaust) in the housing 10a to the outside.

  As shown in FIG. 1, tap water is supplied to the hot water storage tank 21 from a water supply pipe 42 connected to a high-pressure water supply source Sw (for example, a water pipe) via a pressure reducing valve 41. The temperature of the tap water is measured by a water temperature measuring device 67 provided in the water supply pipe 42, such as a thermistor, and is output to the control device 16. The hot water storage tank 21 stores, for example, hot water adjusted to 70 ° C. that has been heated and generated by exhaust heat recovery by the hot water storage water circulation line 22 described above.

  Hot water in the hot water tank 21 flows from the hot water supply pipe 61 into the mixing valve 62. The mixing valve 62 is connected via the water supply pipe 42 and the water supply pipe 42a. The mixing valve 62 adjusts the hot water / water mixing ratio between hot water flowing from the hot water storage tank 21 through the hot water supply pipe 61 and water flowing from the high-pressure feed water source Sw through the water supply pipe 42 and the water supply pipe 42a. The mixed hot water adjusted to a set temperature lower than the temperature of the hot water in the hot water storage tank 21, for example, 30 ° C. is generated. The mixed hot water is connected to the water absorption side of the water heater Wh via the mixed hot water supply pipe 63. The hot water heater Wh supplies hot water supplied from the hot water tap 69 by directly or heating the hot water supplied from the mixed hot water supply pipe 63.

  As shown in FIG. 1, the bypass passage 64 that connects the water supply pipe 42 to the mixed hot water supply pipe 63 is provided with a normally open electromagnetic on-off valve 65 that is open when not energized. For example, the electromagnetic on / off valve 65 cannot be mixed (controlled) with hot water due to a failure of the mixing valve 62 or the control system of the mixing valve 62, and the temperature of the mixed hot water in the mixed hot water supply pipe 63 rises and is preset. When the mixed hot water upper limit temperature (for example, 50 ° C.) is exceeded, the controller 16 switches to the open state. The electromagnetic on-off valve 65 is opened, and water is introduced from the water supply pipe 42 to the mixed hot water supply pipe 63, thereby lowering the temperature of the mixed hot water in the mixed hot water supply pipe 63 and preventing abnormally high temperature hot water. The temperature of the mixed hot water is measured by a hot water temperature measuring device 66 provided, for example, a thermistor or the like, provided downstream of the junction with the bypass passage 64 of the mixed hot water supply pipe 63 and is output to the control device 16.

  By the way, as described above, when the fuel cell module 11 generates power, the reforming water is indispensable for generating the reformed gas (anode gas) in the reforming unit 33. Therefore, it is necessary that an appropriate amount of reforming water is stored in the reforming water tank 15 so that the reforming water can be supplied to the reforming unit 33. Therefore, the control device 16 (more specifically, the CPU) executes the makeup water supply control program shown in FIG. 2 and changes the reforming water according to the amount of the reforming water stored in the reforming water tank 15. When there is a risk of hindering the supply of water, the circulating water is supplied to the reforming water tank 15. Hereinafter, the makeup water supply control program will be described in detail.

  The control device 16 starts execution of the makeup water supply control program at step S100 every time a predetermined short time elapses, and at the subsequent step S101, the third management water level that is the makeup water supply start water level from the water level sensor 15d. It is determined whether or not the signal Ss representing L3 is continuously acquired for a predetermined time t1 or more. Specifically, when the control device 16 continuously acquires the signal Ss for the predetermined time t1 or more, that is, when it is necessary to start the supply of makeup water after the lowering of the water level in the reforming water tank 15 is confirmed. In step S101, “Yes” is determined, and the process proceeds to step S102. On the other hand, when the signal Ss has not been continuously acquired for the predetermined time t1 or longer, the control device 16 determines “No”, proceeds to step S113, and temporarily ends the execution of the makeup water supply control program. And when predetermined short time passes, execution of a makeup water supply control program is started again at Step S100.

  In step S102, the control device 16 sets the value of the operation flag P indicating the state in which the radiator 22b is operated with the normal cooling capacity or the state in which the radiator 22b is operated with the higher cooling capacity than the normal cooling capacity. 22b is set to “0” indicating a state in which it is operated by the normal cooling capacity, and the process proceeds to step S103.

  In step S103, the controller 16 determines that the first temperature T1 of the hot water flowing from the first temperature sensor 22c through the hot water supply pipe 22e is less than the first predetermined temperature Td1 (less than the first predetermined temperature), and Then, it is determined whether or not this state continues for the first predetermined time t2 or longer (continues for the first predetermined time or longer). Here, the first predetermined temperature Td1 is set to a temperature that does not cause thermal degradation of the ion exchange resin constituting the water purifier 14, for example. The first predetermined time t2 is set longer than the predetermined time t1.

  If the first temperature T1 is less than the first predetermined temperature Td1 and this state continues for the first predetermined time t2 or longer, the control device 16 determines “Yes” in step S103 and proceeds to step S104. move on. On the other hand, when the first temperature T1 is equal to or higher than the first predetermined temperature Td1, or when the first temperature T1 is lower than the first predetermined temperature Td1 during the cooling by the radiator 22b, the control device 16 If it is less than the predetermined time t2, that is, if it is necessary to operate the radiator 22b with a cooling capacity higher than the normal cooling capacity to cool the first temperature T1 of the stored hot water, “No” is determined in step S103. Determine and proceed to step S107.

  In step S104, the control device 16 starts from the state in which the entire amount of hot water flowing through the hot water supply pipe 22e is supplied to the heat exchanger 12, and uses a part (approximately several percent) of the hot water as make-up water as the reforming water tank 15 To adjust (change) the valve opening degree of the three-way valve 22d. When the control device 16 opens the three-way valve 22d, the control device 16 proceeds to step S105. Here, in the following description, the state of the valve opening of the three-way valve 22d that supplies the entire amount of hot water to the heat exchanger 12 is referred to as a “fully closed state”, and a part of the hot water is reformed as makeup water. The state of the valve opening degree of the three-way valve 22d supplied to the water tank 15 is referred to as “open state”.

  As described above, when the three-way valve 22d is opened, the makeup water whose first temperature T1 is lower than the first predetermined temperature Td1 flows toward the makeup water supply pipe 22f. The make-up water supply pipe 22f lowers and adjusts the water pressure of the make-up water that flows in (falls down) by the pressure loss part 22f1 (U-shaped part), and flows the make-up water whose water pressure is adjusted to the water supply valve 22g. In the present embodiment, the water supply valve 22g is switched from closed to open by the control device 16 as the three-way valve 22d shifts (switches) from the fully closed state to the open state. Thereby, makeup water is supplied to the water purifier 14, and the water purification device 14 purifies the makeup water and supplies it to the reforming water tank 15.

  In step S105, the control device 16 signals the signal level Sf representing the second control water level L2 that is the supply water supply stop water level from the water level sensor 15d for the water level of the reforming water tank 15 to which supply water is supplied as described above. Whether or not is acquired. That is, the control device 16 determines whether or not to stop the supply of makeup water based on the water level of the reforming water tank 15 to which makeup water is supplied. Specifically, the control device 16 continues to determine “No” in step S105 until the signal Sf is acquired from the water level sensor 15d, and acquires the signal Sf from the water level sensor 15d. When the water level reaches the second management water level L2 for stopping the supply of makeup water, “Yes” is determined in step S105, and the process proceeds to step S106.

  In step S106, the control device 16 controls the three-way valve 22d opened in step S104 to a fully closed state. Thereby, the supply of makeup water from the stored hot water supply pipe 22e via the makeup water supply pipe 22f is stopped, and the entire amount of stored hot water flowing through the stored hot water supply pipe 22e is supplied to the heat exchanger 12. When the control device 16 controls the three-way valve 22d to be fully closed, the control device 16 proceeds to step S110. In the present embodiment, the control device 16 switches the water supply valve 22g from open to closed as the three-way valve 22d is controlled to be fully closed.

  On the other hand, when it is determined “No” in step S103, that is, when it is necessary to further cool the hot water flowing through the hot water supply pipe 22e, the control device 16 proceeds to step S107. In step S107, the control device 16 sets the value of the operation flag P to “1” representing a state in which the radiator 22b is operated with a cooling capacity higher than the normal cooling capacity. Thereby, the control device 16 operates the radiator 22b with a higher cooling capacity than usual, and proceeds to step S108.

  In step S108, the control device 16 increases the electric power (current) supplied to the motor that rotates the fan of the radiator 22b as compared with the normal operation, and cools the radiator 22b that cools the hot water flowing through the hot water supply pipe 22e. Increase ability. Specifically, in the power control for supplying power (current) to the motor of the radiator 22b, the control device 16 increases the power supply duty ratio Dr by a predetermined value α with respect to the duty ratio Dr1 during normal operation, for example. . That is, the control device 16 supplies electric power (current) with a duty ratio Dr (= Dr1 + α) to the motor. Thus, the radiator 22b increases the cooling capacity as the number of rotations of the fan increases, and cools the hot water stored in the hot water supply pipe 22e. Thus, if the control apparatus 16 raises the cooling capacity of the radiator 22b, it will progress to step S109.

  In step S109, as in step S103, the control device 16 determines that the first temperature T1 of the hot water flowing from the first temperature sensor 22c through the hot water supply pipe 22e is less than the first predetermined temperature Td1, and Then, it is determined whether or not this state continues for the first predetermined time t2 or more. Specifically, in step S109, the control device 16 continues to determine “No” until the first temperature T1 is lower than the first predetermined temperature Td1 and this state continues for the first predetermined time t2 or longer.

  When the first temperature T1 is lower than the first predetermined temperature Td1 and this state continues for the first predetermined time t2 or longer, that is, the control device 16 operates the radiator 22b to set the first temperature of the stored hot water. If it is not necessary to cool T1, “Yes” is determined in step S109, and the process proceeds to step S104. As described above, when the hot water flowing through the hot water supply pipe 22e is cooled, the control device 16 executes the step processes of step S104 to step S106 as described above, and proceeds to step S110.

  In step S110, the control device 16 determines whether the value of the operation flag P is “0”, that is, whether the radiator 22b is inactive. If the value of the operation flag P is “0”, the control device 16 determines “Yes”, proceeds to step S113, and temporarily ends the execution of the makeup water supply control program. In this case, since the radiator 22b is operated with the normal cooling capacity, the control device 16 operates the radiator 22b as it is. And control apparatus 16 will start execution of a makeup water supply control program again in Step S100, if predetermined short time passes.

  On the other hand, if the value of the operation flag P is “1”, the control device 16 determines “No” and proceeds to step S111. In this case, the control device 16 operates the radiator 22b with a cooling capacity higher than the normal cooling capacity by the step process of step S108. For this reason, the control apparatus 16 performs each step process after step S111, and operates the radiator 22b by normal cooling capacity.

  In step S111, the control device 16 calculates the duty ratio Dr (= Dr1 + α) of the electric power (current) supplied to the motor of the radiator 22b according to the operation flag P being “1” as the duty ratio during normal operation. Change (return) to the ratio Dr1. Specifically, the control device 16 subtracts the predetermined value α from the duty ratio Dr, changes the duty ratio Dr1 during normal operation, and proceeds to step S112. Thus, the radiator 22b operates with a normal cooling capacity.

  In step S112, the control device 16 sets the value of the operation flag P set to “1” to “0”, proceeds to step S113, and temporarily ends the execution of the makeup water supply control program. And control apparatus 16 will start execution of a makeup water supply control program again in Step S100, if predetermined short time passes.

  As can be understood from the above description, according to the fuel cell system 1 of the above-described embodiment, the fuel cell 34 that generates power using the fuel and the oxidant gas, the water vapor obtained by evaporating the reforming raw material and the reforming water, The reforming section 33 for generating fuel from the fuel cell 34 and supplying the fuel to the fuel cell 34 and the reforming raw material supply pipe 11a connected to the reforming raw material supply source Gs are provided from the supply source Gs to the reforming section. A raw material pump 11a1 as a reforming raw material supply device that pumps the reforming raw material to 33, and a reforming water tank 15 that stores the reforming water supplied to the reforming unit 33 via the reforming water supply pipe 11b; Between the combustion exhaust gas generated by burning the fuel off-gas (anode off-gas) and the oxidant gas (cathode off-gas) from the fuel cell 34 and the circulating water supplied from the hot water storage tank 21 through the hot water storage water supply pipe 22e. Exhaust gas after heat exchange A heat exchanger 12 serving as a condenser that condenses the water vapor contained therein to generate condensed water, and a condensed water supply pipe 12a that connects the reforming water tank 15 and the heat exchanger 12 to provide condensed water. A water purifier 14 that purifies and supplies reformed water to the reformed water tank 15, a radiator 22 b that is provided in the hot water storage water supply pipe 22 e and cools the circulating water supplied from the hot water tank 21, and a fuel cell 34. A control device 16 that controls power generation in an integrated manner, and is provided between the heat exchanger 12 and the radiator 22b of the hot water supply pipe 22e, and is provided on the heat exchanger 12 side. A three-way valve as an adjustment valve capable of adjusting the circulating water supply amount of flowing circulating water and the makeup water supply amount of makeup water separated from the circulating water and flowing toward the reforming water tank 15 according to control by the control device 16 22d and hot water supply pipe 2 a first temperature sensor 22c that is provided between the three-way valve 22d and the radiator 22b, detects a first temperature T1 of the circulating water that has passed through the radiator 22b, and outputs the first temperature T1 to the controller 16; A supply water supply pipe 22f for supplying makeup water from the three-way valve 22d to the water purification device 14 by connecting the valve 22d and the water purification device 14, and reformed water generated from the condensed water and makeup water by the water purification device 14 Detects the first management water level L1, the second management water level L2, the third management water level L3 and the fourth management water level L4 as the water levels stored in the reforming water tank 15, and the first management water level L1 and the second management water level L2 are detected. A water level sensor 15d that outputs the third management water level L3 and the fourth management water level L4 to the control device 16, and adjusts the supply of the makeup water from the hot water storage tank 21 to the reforming water tank 15 Is provided. Then, when the water level detected by the water level sensor 15d becomes the third management water level L3 that is a preset makeup water supply start water level, the control device 16 detects the circulating water detected by the first temperature sensor 22c. When the first temperature T1 becomes less than a preset first predetermined temperature Td1 (less than the first predetermined temperature), the makeup water supply pipe 22f and the water purification are increased by increasing the makeup water supply amount by the three-way valve 22d from zero. When makeup water is supplied to the reforming water tank 15 through the vessel 14, and the water level detected by the water level sensor 15d reaches the second management water level L2, which is a preset makeup water supply stop water level, three-way The makeup water supply amount by the valve 22d is returned to zero.

  According to this, when the water level of the reforming water tank 15 becomes the third control water level L3, that is, the control device 16 is water vapor (reforming water) supplied from the reforming water tank 15 to the reforming unit 33. In the case where there is a possibility that the supply water is insufficient, the makeup water adjusting unit 70 can be operated. When the makeup water adjusting unit 70 is operated, the three-way valve 22d separates makeup water from the circulating water supplied from the hot water storage tank 21 and having the first temperature T1 lower than the first predetermined temperature Td1, and the separated makeup water is separated. Can be supplied to the water purifier 14. Then, the water purifier 14 can supply the reformed water obtained by purifying the separated makeup water to the reformed water tank 15. As a result, during the power generation operation of the fuel cell system 1, a necessary and sufficient amount of reforming water can be always stored in the reforming water tank 15. As a result, a necessary and sufficient amount of reforming water (steam) can be supplied from the reforming water tank 15 to the reforming unit 33, and the reforming unit 33 generates fuel consumed by the fuel cell 34 to generate fuel. The power generation of the battery 34 can be continued. Therefore, even in a situation where there is a concern about the shortage of reforming water, the power generation operation of the fuel cell system 1 can be continued without lowering the power generation efficiency.

  Further, the makeup water adjusting unit 70 stores hot water (circulated water) flowing through the hot water supply pipe 22e by a three-way valve 22d provided in the hot water supply pipe 22e for supplying circulating water from the hot water tank 21 to the heat exchanger 12. A part of the water is separated as makeup water, and the reformed water purified from the makeup water by the water purifier 14 can be supplied to the reformed water tank 15. Thereby, for example, there is no need to provide a dedicated supply pipe for supplying water to the reforming water tank 15 from the outside of the fuel cell system 1, and the fuel cell system 1 can be configured in a simple manner and the dedicated supply pipe. The cost for providing can be reduced.

  Further, the makeup water adjusting unit 70 can use a part of the stored hot water (circulated water) supplied from the hot water storage tank 21 as makeup water. In this case, the stored hot water (circulated water) stored in the hot water storage tank 21 has impurities removed by a strainer and the like, and becomes temporarily relatively hot due to heat exchange with the heat exchanger 12. Thereby, the hot water (circulated water) has been subjected to a simple dechlorination treatment, and even if makeup water separated from the hot water (circulated water) is supplied to the water purifier 14, The load when the replacement resin purifies the makeup water can be reduced. As a result, it is possible to reduce the size of the expensive water purifier 14 (ion exchange resin), so that the entire fuel cell system 1 can be reduced in size and the cost can be reduced.

  In this case, the control device 16 continues for the first predetermined time t2 or more (continues for the first predetermined time or more) set in advance in a state where the first temperature T1 is less than the first predetermined temperature Td1 (less than the first predetermined temperature). In this case, the makeup water supply amount by the three-way valve 22d is increased from zero.

  According to this, when the first temperature T1 of the hot water (circulated water), that is, the first temperature T1 of the makeup water is surely lower than the first predetermined temperature Td1, the water purifier 14 is supplied from the three-way valve 22d. Makeup water can be supplied. Thereby, it can suppress effectively that the ion exchange resin of the water refiner | purifier 14 is thermally deteriorated with makeup water. Therefore, the replacement frequency of the expensive ion exchange resin can be greatly reduced, and the running cost associated with the power generation operation of the fuel cell system 1 can be reduced.

  Further, in these cases, the control device 16 causes the radiator 22b to increase the cooling efficiency for cooling the circulating water of the radiator 22b when the first temperature T1 is equal to or higher than the first predetermined temperature Td1 (first predetermined temperature or higher). Is activated.

  According to this, in the case where the first temperature T1 is equal to or higher than the first predetermined temperature Td1 (first predetermined temperature or higher), the control device 16 increases the cooling efficiency of the radiator 22b and transfers from the hot water storage tank 21 to the heat exchanger 12. The first temperature T1 of hot water (circulated water), that is, make-up water flowing through the hot water supply pipe 22e can be quickly lowered. Thereby, it can suppress effectively that the ion exchange resin of the water refiner | purifier 14 is thermally deteriorated with makeup water.

  Further, in these cases, the makeup water supply pipe 22f has a pressure loss portion 22f1 bent in a U shape that causes pressure loss in the makeup water flowing from the three-way valve 22d toward the water purifier 14.

  According to this, the pressure loss part 22f1 can reduce the water pressure of the makeup water supplied from the three-way valve 22d to the water purifier 14 via the makeup water supply pipe 22f. Thereby, for example, it is effectively suppressed that the water pressure of the makeup water gives a mechanical load that causes deformation to the ion exchange resin of the water purifier 14. Therefore, the replacement frequency of the expensive ion exchange resin can be greatly reduced, and the running cost associated with the power generation operation of the fuel cell system 1 can be reduced.

(Modification)
In the above-described embodiment, the controller 16 has the first temperature T1 of the hot water flowing through the hot water supply pipe 22e less than the first predetermined temperature Td1, that is, the first temperature T1 heats the ion exchange resin of the water purifier 14. When the temperature does not deteriorate, the three-way valve 22d is opened to supply (replenish) makeup water to the reforming water tank 15. In this case, it is possible to prevent the water purifier 14 from being thermally deteriorated more reliably. Hereinafter, although this modified example is demonstrated, it demonstrates in detail focusing on a different part from the said embodiment.

  In this modified example, as shown in FIG. 4, the second temperature sensor 22h is disposed between the makeup water supply pipe 22f and the water supply valve 22g. That is, in this modified example, the second temperature sensor 22 h is included in the makeup water adjusting unit 70. The second temperature sensor 22h detects the temperature T2 of the makeup water supplied from the three-way valve 22d and flows through the makeup water supply pipe 22f (hereinafter referred to as “second temperature T2”), and transmits the detected temperature to the control device 16. ing. Moreover, in this modification, the control apparatus 16 controls opening or closing of the water supply valve 22g based on 2nd temperature T2 acquired from the 2nd temperature sensor 22h.

  In this modification, the control device 16 executes the makeup water supply control program shown in FIG. In the makeup water supply control program according to this modification, steps S120 and S121 are newly added between step S104 and step S105, compared to the makeup water supply control program shown in FIG. 3 of the above embodiment. The difference is that step S122 is newly added between step S105 and step S106.

  In this modified example, when the control device 16 controls the three-way valve 22d to be open in step S104, the control device 16 proceeds to step S120. In step S120, the control device 16 determines that the second temperature T2 of the makeup water supplied from the second temperature sensor 22h to the makeup water supply pipe 22f is less than the second predetermined temperature Td2 (less than the second predetermined temperature), and Then, it is determined whether or not this state continues for the second predetermined time t3 or longer (continues for the second predetermined time or longer). Here, the second predetermined temperature Td2 is set to a temperature that does not cause thermal degradation of the ion exchange resin constituting the water purifier 14, for example. The second predetermined time t3 is set longer than the predetermined time t1.

  Specifically, in step S120, the control device 16 continues to determine “No” until the second temperature T2 is lower than the second predetermined temperature Td2 and this state continues for the second predetermined time t3 or more. If the second temperature T2 is lower than the second predetermined temperature Td2 and this state continues for the second predetermined time t3 or longer, the control device 16 determines “Yes” in step S120, The process proceeds to step S121. That is, when the second temperature T2 is lower than the second predetermined temperature Td2 and this state continues for the second predetermined time t3 or more, the second temperature T2 of the makeup water supplied to the makeup water supply pipe 22f is The temperature is surely lower than the second predetermined temperature Td2. Therefore, even if makeup water is supplied to the water purifier 14 from the water supply valve 22g, thermal deterioration of the ion exchange resin of the water purifier 14 is suppressed.

  In step S121, the control device 16 switches the water supply valve 22g from closed to open. Thereby, the makeup water supplied to the makeup water supply pipe 22f is supplied to the water purifier 14 through the water supply valve 22g. Therefore, the water purifier 14 purifies the makeup water and supplies it to the reforming water tank 15.

  As described above, the control device 16 switches the water supply valve 22g to open in step S121, and then the water level of the reforming water tank 15 to which makeup water is supplied as described above in step S105. It is determined whether or not the signal Sf representing the second control water level L2 is acquired from the sensor 15d. Then, when the control device 16 acquires the signal Sf from the water level sensor 15d, in other words, when the water level of the reforming water tank 15 reaches the second management water level L2 that is the makeup water supply stop water level that stops the supply of makeup water. In S105, “Yes” is determined, and the process proceeds to Step S122.

  In step S122, the control device 16 switches the water supply valve 22g switched to open in step S121 to closed, and proceeds to step S106. Thereby, even if the three-way valve 22d is in the open state and the makeup water is supplied to the makeup water supply pipe 22f, the makeup water 14 purifier water and the reforming water tank are switched by closing the feed water valve 22g. The supply to 15 stops. In step S106, the control device 16 controls the three-way valve 22d opened in step S104 to a fully closed state. As a result, the supply of makeup water from the hot water supply pipe 22e is stopped, and the entire amount of hot water flowing through the hot water supply pipe 22e is supplied to the heat exchanger 12.

  As can be understood from the above description, according to the fuel cell system 1 of the above modified example, in addition to the case of the above embodiment, the makeup water adjusting unit 70 is provided in the makeup water supply pipe 22f to supply makeup water. A second temperature sensor 22h that detects a second temperature T2 of makeup water flowing through the pipe 22f and outputs the second temperature T2 to the control device 16, a water purifier 14 of the makeup water supply pipe 22f, and a second temperature sensor 22h; A water supply valve 22g that is provided between the supply water supply pipe 22f and the water supply valve 22g for switching the flow from the makeup water supply pipe 22f to the water purifier 14 to be closed or closed to block the flow according to the control by the control device 16. 16 is continued for a predetermined second predetermined time t3 or more in a state where the second temperature T2 detected by the second temperature sensor 22h is lower than a predetermined second predetermined temperature Td2 (lower than the second predetermined temperature). ( When the water supply valve 22g is opened), the supply of makeup water is permitted from the makeup water supply pipe 22f to the reforming water tank 15 through the water purifier 14, and the water level sensor 15d When the detected water level becomes the third management water level L3, the water supply valve 22g is switched to close so that the makeup water is shut off from the makeup water supply pipe 22f to the reforming water tank 15 through the water purifier 14. Configured.

  According to this, after the second temperature T2 detected by the second temperature sensor 22h becomes lower than the second predetermined temperature Td2, the water supply valve 22g is switched from closed to open. Therefore, for example, even when an error occurs in the first temperature T1 detected by the first temperature sensor 22c, the second temperature T2 of the makeup water flowing through the makeup water supply pipe 22f on the downstream side of the three-way valve 22d is set. The second temperature sensor 22h can detect and control opening / closing of the water supply valve 22g according to the second temperature T2. Accordingly, it is possible to reliably prevent erroneous supply of hot makeup water that causes thermal degradation of the ion exchange resin of the water purifier 14. About the other effect, the effect similar to the said embodiment is acquired.

  In carrying out the present invention, the present invention is not limited to the above embodiment and the above modification, and various modifications can be made without departing from the object of the present invention.

  For example, in the above-described embodiment and the above-described modification, the make-up water adjusting unit 70 is U-shaped in the make-up water supply pipe 22f in order to cause a pressure loss in the make-up water supplied from the open three-way valve 22d and reduce the water pressure. The pressure loss portion 22f1 is bent into a shape. Instead of this, as shown in FIG. 6, it is also possible to provide a pressure loss part 22f2 formed of a throttle (orifice) between the three-way valve 22d and the water supply valve 22g. Even in the case where the pressure loss part 22f2 is provided, the supply water supplied from the three-way valve 22d can be caused to have a pressure loss and the water pressure of the supply water can be lowered, so that it is supplied to the water purifier 14 through the water supply valve 22g. The water pressure of make-up water can be lowered. Therefore, it is possible to prevent the ion exchange resin of the water purifier 14 from being damaged by a high water pressure. As a result, it is possible to suppress the replacement frequency of the expensive water purifier 14 and reduce the running cost of the fuel cell system 1. Can do.

  Moreover, in the said embodiment and modification, the water level sensor 15d was made into the float type sensor. Instead, the water level sensor 15d may be a widely known capacitance type or pressure type sensor. Also in this case, the water level sensor 15 d can detect the first management water level L1 to the fourth management water level L4 as the water level of the reforming water stored in the reforming water tank 15 and transmit it to the control device 16. Therefore, the same effects as those of the above embodiment and the above modification can be obtained.

  In the embodiment and the modification, the radiator 22b is air-cooled. Instead of this, it is also possible to use a water-cooled radiator, other heat radiating device or heat transfer device as the radiator 22b.

  In the above-described embodiment and the above-described modification, in step S108 in the makeup water supply control program shown in FIGS. 3 and 5, the control device 16 sets the rotational speeds of the motor and the fan in order to increase the cooling capacity of the radiator 22b. Increased. In this case, it is possible to increase the rotational speeds of the motor and the fan stepwise so that the operating sound of the radiator 22b is less likely to leak out of the housing 10a.

  Furthermore, in the embodiment and the modification described above, the control device 16 supplies makeup water when the water level of the reforming water in the reforming water tank 15 reaches the second management water level L2 during the power generation operation of the fuel cell system 1. When the reforming water level reaches the third control water level L3, the supply of makeup water is stopped. That is, in the above embodiment and the above modification, during the power generation operation of the fuel cell system 1, the control device 16 determines that the reformed water level is the second control water level L2 and the third control water level L3 of the reforming water tank 15. The supply of make-up water was controlled so that it was in between.

  By the way, when the fuel cell system 1 is stopped in the power generation operation and the water level of the reforming water exists between the second control water level L2 and the third control water level L3 of the reforming water tank 15, the next fuel In preparation for the power generation operation of the battery system 1, the control device 16 preliminarily stores hot water (make-up water) in the reforming water tank so that the reforming water level in the reforming water tank 15 becomes the first control water level L1. 15 can also be supplied. Thereby, in the next power generation operation of the fuel cell system 1, for example, the fuel cell system 1 can be quickly started by quickly shifting from the warm air mode to the power generation mode. However, in this case, on condition that the first temperature T1 of the hot water stored in the hot water tank 21 is lower than the first predetermined temperature Td1 (or / and the second temperature T2 is the second predetermined temperature Td2). The control device 16 supplies (supplements) hot water storage water (make-up water) to the reforming water tank 15.

DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 10 ... Power generation unit, 10a ... Housing, 10b ... Intake port, 10c ... Exhaust port for ventilation, 10d ... Exhaust port for combustion exhaust gas, 11 ... Fuel cell module, 11a ... Reformation material supply pipe 11a1 ... Raw material pump, 11b ... Reformed water supply pipe, 11b2 ... Reformed water pump, 11c ... Cathode air supply pipe, 11c1 ... Cathode air blower, 11c2 ... Electric motor, 11c3 ... Flow sensor, 11d ... Exhaust pipe, 12 ... heat exchanger (condenser), 12a ... condensed water supply pipe, 12b ... drain line, 13 ... inverter device, 14 ... water purifier, 15 ... reformed water tank, 15a ... overflow line, 15b ... water receiving member 15c ... Drain pipe, 15d ... Water level sensor, 16 ... Control device, 17a ... System power supply, 17b ... Power supply line, 17c ... External power load, 20 ... Exhaust heat recovery system 21 ... Hot water tank, 22 ... Hot water circulation line, 22a ... Hot water circulation pump, 22b ... Radiator, 22c ... First temperature sensor, 22d ... Three-way valve (regulating valve), 22e ... Hot water supply pipe, 22f ... Make-up water Supply pipe, 22f1 ... pressure loss part, 22f2 ... pressure loss part, 22g ... feed valve, 22h ... second temperature sensor, 31 ... casing, 32 ... evaporation part, 33 ... reforming part, 34 ... fuel cell, 34a ... cell, 34b ... Fuel flow path, 34c ... Air flow path, 35 ... Manifold, 36 ... Combustion part, 36a1, 36a2 ... Ignition heater, 37 ... Flame, 38 ... Reformed gas delivery pipe, 41 ... Pressure reducing valve, 42 ... Feed water pipe, 42a ... Water supply pipe, 54 ... Check valve, 55 ... Ventilation fan, 61 ... Hot water supply pipe, 62 ... Mixing valve, 63 ... Mixed hot water supply pipe, 64 ... Bypass passage, 65 ... Electromagnetic on-off valve, 66 ... Hot water temperature measurement Equipment, 67 ... water Measuring device, 69 ... Hot water tap, 70 ... Make-up water adjustment unit, Dr ... Duty ratio, Dr1 ... Duty ratio, Gs ... Supply source, L1 ... First management water level, L2 ... Second management water level (Supply water supply stop water level) L3 ... third control water level (supply water supply stop water level), L4 ... fourth control water level, P ... operation flag, Sw ... high pressure feedwater, T1 ... first temperature, Td1 ... first predetermined temperature, T2 ... second Temperature, Td2 ... second predetermined temperature, t1 ... predetermined time, t2 ... first predetermined time, t3 ... second predetermined time, Wh ... hot water heater, α ... predetermined value

Claims (5)

A fuel cell that generates electricity using fuel and oxidant gas;
A reforming unit that generates the fuel from a reforming raw material and water vapor obtained by evaporating reforming water and supplies the fuel to the fuel cell;
A reforming material supply device that is provided in a reforming material supply pipe connected to the reforming material supply source and pumps the reforming material from the supply source to the reforming unit;
A reforming water tank for storing the reforming water supplied to the reforming section via a reforming water supply pipe;
Included in the combustion exhaust gas by exchanging heat between the combustion exhaust gas generated by burning the fuel off-gas and oxidant gas from the fuel cell and the circulating water supplied from the hot water storage tank through the hot water supply pipe A condenser that condenses water vapor to produce condensed water;
A water purifier provided in a condensed water supply pipe connecting the reformed water tank and the condenser to purify the condensed water and supply the reformed water to the reformed water tank;
A radiator that is provided in the hot water supply pipe and cools the circulating water supplied from the hot water tank;
A fuel cell system comprising: a control device that performs overall control of power generation of the fuel cell;
A circulating water supply amount of the circulating water that flows between the condenser and the radiator of the hot water supply pipe and flows to the condenser side, and is separated from the circulating water and An adjustment valve capable of adjusting the makeup water supply amount flowing to the side according to the control by the control device;
A first temperature sensor that is provided between the adjustment valve of the hot water supply pipe and the radiator, detects a first temperature of the circulating water that has passed through the radiator, and outputs the first temperature to the control device When,
A makeup water supply pipe for connecting the regulation valve and the water purifier to supply the makeup water from the regulation valve to the water purification device;
A water level sensor that detects a level of the reformed water generated from the condensed water and the makeup water by the water purifier and stored in the reformed water tank, and outputs the water level to the control device. A replenishing water adjustment unit for adjusting the supply of the makeup water from the hot water storage tank to the reforming water tank,
The controller is
When the water level detected by the water level sensor is a preset makeup water supply start water level,
When the first temperature of the circulating water detected by the first temperature sensor becomes lower than a preset first predetermined temperature, the replenishment water supply amount by the adjustment valve is increased from zero to the replenishment Supplying the makeup water to the reformed water tank through a water supply pipe and the water purifier;
A fuel cell system configured to return the makeup water supply amount by the adjustment valve to zero when the water level detected by the water level sensor reaches a preset makeup water supply stop water level. The controller is
When the first temperature continues for more than a first predetermined time in a state of being less than the first predetermined temperature,
The fuel cell system according to claim 1, wherein the makeup water supply amount by the regulating valve is increased from zero. The controller is
When the first temperature is equal to or higher than the first predetermined temperature,
The fuel cell system according to claim 1 or 2, wherein the radiator is operated so that a cooling efficiency of cooling the circulating water of the radiator is increased. The makeup water adjusting unit is
A second temperature sensor provided in the makeup water supply pipe for detecting a second temperature of the makeup water flowing through the makeup water supply pipe and outputting the second temperature to the control device;
Provided between the water purifier of the make-up water supply pipe and the second temperature sensor to allow the flow of the make-up water from the make-up water supply pipe to the water purifier or to block the flow. A water supply valve that switches closing according to control by the control device,
The controller is
When the second temperature detected by the second temperature sensor continues for a preset second predetermined time in a state where the second temperature is less than a preset second predetermined temperature,
Switching the water supply valve to open, allowing the supply of makeup water from the makeup water supply pipe to the reforming water tank via the water purifier,
When the water level detected by the water level sensor becomes the makeup water supply stop water level, the water supply valve is switched to close to the reforming water tank from the makeup water supply pipe via the water purifier. The fuel cell system according to any one of claims 1 to 3, wherein the fuel cell system is configured to shut off the makeup water. The makeup water supply pipe is
5. The fuel cell system according to claim 1, further comprising a pressure loss unit that causes a pressure loss in the makeup water flowing from the regulating valve toward the water purifier.

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