JP6939316B2 - Fuel cell system - Google Patents

Description

The present invention relates to a fuel cell system.

Conventionally, for example, a fuel cell device disclosed in Patent Document 1 below has been 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 the condensed water generated by cooling the exhaust gas is collected in the condensed water tank and hot water in the hot water storage tank. Is to be stored. 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 flow path.

Further, 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 that makes it difficult for the pump to pump up to the reforming part, and a normal level between the overflow level and the abnormal level. If it is between, the output of the fuel cell is reduced.

Japanese Unexamined Patent Publication No. 2001-325982 Japanese Unexamined Patent Publication No. 2016-177998

Generally, in a fuel cell system, a reforming section is provided to which a mixed gas in which a reforming raw material and steam reformed water are mixed is supplied, and the mixture is mixed by a steam reforming reaction generated inside the reforming section. The gas is reformed to produce reformed gas (fuel). Then, the generated reformed gas (fuel) is supplied to the fuel cell to generate electricity.

By the way, in the above-mentioned conventional fuel cell device (fuel cell system), the condensed water condensed by the heat exchanger is recovered as reformed water. In this case, it is possible to promote the generation of condensed water in the heat exchanger and improve the utilization efficiency of the reformed water by cooling the hot water supplied from the hot water tank with the radiator. However, it is difficult to recover all the steam components in the exhaust gas, and if the reformed water stored in the reformed water tank becomes insufficient and the steam cannot be supplied to the reformed part, the fuel The battery system needs to be shut down.

On the other hand, in the above-mentioned conventional fuel cell system, when the water level of the reformed water stored in the water storage device (reformed water tank) drops, the amount of reformed water recovered is increased by limiting the output. , Avoid shutting down the fuel cell system. However, when the output is limited, the power generation efficiency of the fuel cell system may decrease and the energy utilization efficiency may decrease.

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 power generation operation without causing a decrease in power generation efficiency due to a shortage of reformed water.

In order to solve the above problems, the invention of the fuel cell system according to claim 1 uses fuel from a fuel cell that generates power by using fuel and an oxidizing agent gas, and steam vapor obtained by evaporating reforming raw materials and reforming water. The reforming raw material is pumped from the supply source to the reforming section, which is provided in the reforming section that generates and supplies fuel to the fuel cell and the reforming raw material supply pipe connected to the supply source of the reforming raw material. It is generated by burning the fuel off gas and oxidant gas from the fuel cell, the reforming raw material supply device, the reforming water tank that stores the reforming water supplied to the reforming part via the reforming water supply pipe, and the reforming part. A condenser that exchanges heat between the combustion exhaust gas and the circulating water supplied from the hot water storage tank via the hot water storage water supply pipe to condense the water vapor contained in the combustion exhaust gas to generate condensed water, and reformed water. A water purifier provided in the condensed water supply pipe connecting the tank and the condenser to purify the condensed water and supply the reformed water to the reformed water tank, and a water purifier provided in the hot water storage pipe to supply the reformed water from the hot water storage tank. It is a fuel cell system equipped with a radiator that cools the circulating water and a control device that controls the power generation of the fuel cell, and is provided between the condenser of the hot water storage pipe and the radiator. , The circulating water supply amount of the circulating water flowing to the condenser side and the make-up water supply amount of the make-up water separated from the circulating water and flowing to the reforming water tank side can be adjusted according to the control by the control device. A first temperature sensor provided between the regulating valve of the hot water storage pipe and the radiator, which detects the first temperature of the circulating water that has passed through the radiator, and outputs the first temperature to the control device, and the regulating valve. The water is stored in the make-up water supply pipe that connects to the water purifier and supplies make-up water from the regulating valve to the water purifier, and the reformed water tank of the condensed water and the reformed water generated from the make-up water by the water purifier. It is equipped with a water level sensor that detects the water level and outputs the water level to the control device, and a make-up water adjustment unit that adjusts the supply of the make-up water from the hot water storage tank to the reformed water tank. When the detected water level reaches the preset make-up water supply start water level, and the first temperature of the circulating water detected by the first temperature sensor becomes less than the preset first predetermined temperature. The amount of make-up water supplied by the regulating valve is increased from zero to supply make-up water to the reformed water tank via the make-up water supply pipe and the water purifier, and the water level detected by the water level sensor is set in advance. It is configured to return the amount of make-up water supplied by the regulating valve to zero when the water supply stop water level is reached.

According to this, when the water level of the reformed water tank reaches the make-up water supply start water level, that is, the steam (reformed water) supplied from the reformed water tank to the reformed part may be insufficient. The make-up water adjusting unit can be operated when there is a tendency. When the make-up water adjustment unit operates, the adjustment valve separates the make-up water from the circulating water supplied from the hot water storage tank and whose first temperature is lower than the first predetermined temperature, and the separated make-up water is used as a water purifier. Can be supplied. Then, the water purifier can supply the reformed water obtained by purifying the separated make-up water to the reformed water tank. As a result, a necessary and sufficient amount of reformed water can be stored in the reformed water tank at all times during the power generation operation of the fuel cell system. As a result, the reforming water tank can supply the required and sufficient amount of reforming water (steam) to the reforming part, and the reforming part generates the fuel consumed by the fuel cell to generate electricity from the fuel cell. Can be continued. 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 reformed water.

It is the schematic which shows the outline 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 make-up water supply control program executed by the control device of FIG. It is the schematic which shows the outline of the fuel cell system which concerns on the modification of embodiment. FIG. 5 is a flowchart showing a make-up water supply control program executed by the control device of FIG. 4 according to a modified example. It is a schematic diagram which shows the outline of the fuel cell system which concerns on other modification of the Embodiment.

Hereinafter, the fuel cell system according to the embodiment of the present invention will be described with reference to the drawings. In the following embodiments and the respective modifications, the same or equal parts are designated by the same reference numerals. Further, each figure used for explanation is a conceptual view, and the shape of each part may not always be exact.

As shown in FIG. 1, the fuel cell system 1 includes a power generation unit 10 and a hot water storage tank 21. The power generation unit 10 includes a housing 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 make-up water adjusting unit 70.

The hot water storage 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 degrees to 40 degrees). The upper and lower layers have almost the same temperature. The hot water storage tank 21 stores hot water, and a hot water storage water circulation line 22 through which the hot water is circulated (circulated in the direction of the arrow in the figure) is connected.

The fuel cell module 11, the heat exchanger 12, the inverter device 13, the water purifier 14, the reformed water tank 15, the control device 16, the make-up water adjusting unit 70, and the hot water storage tank 21 are housed in the housing 10a. 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 the fuel cell 34. The fuel cell module 11 is supplied with a reforming raw material, reforming water, and air (cathode air) as an oxidizing agent gas (cathode gas). The reforming raw material is a reforming gaseous fuel such as natural gas or LP gas, or a reforming liquid fuel such as kerosene, gasoline or methanol. In this embodiment, a case where natural gas is used as a raw material for reforming is illustrated. Specifically, the fuel cell module 11 has a reforming raw material supply pipe 11a in which one end is connected to a supply source Gs (for example, a gas supply pipe of city gas (natural gas)) to supply a reforming raw material. The other end is connected to the evaporation unit 32, which will be described later. The reforming raw material supply pipe 11a is provided with a raw material pump 11a1 (a reforming raw material supply device) that pumps the reforming raw material to the evaporation unit 32.

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

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

An exhaust pipe 11d from the fuel cell module 11 is connected (penetrated) to the heat exchanger 12. A condensed water supply pipe 12a 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 in this way, the combustion exhaust gas from the fuel cell module 11 is introduced into the heat exchanger 12 through the exhaust pipe 11d and exchanges heat with the circulating hot water storage water. It is condensed and cooled. After that, the combustion exhaust gas is discharged to the outside of the housing 10a from the combustion exhaust gas exhaust port 10d through the exhaust pipe 11d. Further, the condensed condensed water falls by its own weight and is 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 storage tank 21. The exhaust pipe 11d is provided with a drain pipe 12b that branches from the downstream side of the heat exchanger 12 and communicates with the water receiving member 15b of the reforming water tank 15.

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

The hot water storage water circulation pump 22a draws hot water from the lower layer of the hot water storage tank 21 and supplies it to the heat exchanger 12 via the hot water storage water supply pipe 22e constituting the hot water storage 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 stored water supplied from the hot water storage water circulation pump 22a toward the heat exchanger 12 by controlling the operation by the control device 16 as described later.

The first temperature sensor 22c is arranged between the radiator 22b and the heat exchanger 12, and the temperature T1 of the hot water stored as circulating water that passes through the radiator 22b and flows through the hot water supply pipe 22e (hereinafter, “first”. It is called "temperature T1") and is transmitted to the control device 16. The three-way valve 22d is arranged between the first temperature sensor 22c and the heat exchanger 12. The three-way valve 22d supplies the hot water stored water cooled by the radiator 22b to the heat exchanger 12, and supplies the make-up water separated from the hot water storage water (circulating water) flowing through the hot water storage water supply pipe 22e via the make-up water supply pipe 22f. It is supplied to the water purifier 14 and thus the reformed water tank 15.

The valve opening degree of the three-way valve 22d is adjusted by the control device 16, and the amount of hot water supplied to the heat exchanger 12 cooled by the radiator 22b, in other words, the reforming of the hot water stored 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 whose valve opening degree can be changed, and the cooled hot water is used as the circulating water supply amount of the hot water (circulating water) supplied to the heat exchanger 12 and the reformed water. The ratio of the make-up water supplied to the tank 15 to the make-up water supply amount 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 a pressure loss in the make-up water flowing through the make-up water supply pipe 22f to lower the water pressure of the make-up water. .. The make-up water supply pipe 22f is provided with a water supply valve 22g for supplying make-up water to the water purifier 14. The water supply valve 22g is switched by the control device 16 to open that allows supply of make-up water to the water purifier 14 and close that cuts off the supply of make-up 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 the make-up water to the reforming water tank 15, and when the three-way valve 22d does not supply the make-up 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 make-up water supply pipe 22f, the pressure loss section 22f1, and the water supply valve 22g constitute the make-up water adjusting section 70.

The inverter device 13 inputs DC power (voltage) output from the fuel cell 34, converts it into predetermined AC power (voltage), and connects it to an AC system power supply 17a and an external power load 17c (for example, an electric appliance). Output to the power supply 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 supply 17a and power from the inverter device 13 are supplied. Further, the inverter device 13 inputs AC power (voltage) from the system power supply 17a via the power supply line 17b and converts it into predetermined DC power (voltage) to be used as an auxiliary machine (each pump, blower, etc.) or a control device. Output to 16.

The water purifier 14 purifies the condensed water and the make-up water with an ion exchange resin. The water purifier 14 communicates with the reformed water tank 15, so that the purified condensed water and make-up water are supplied to the reformed water tank 15.

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

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 15d is included in the make-up water adjusting unit 70. The water level sensor 15d is, for example, a float type sensor, which converts the vertical amount of the float into a resistance value by 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 residual water amount as the first control water level L1, the second control water level L2, the third control water level L3, and the fourth control water level L4. The first controlled water level L1 is the water level at which the reforming water tank 15 is full. The second control water level L2 is a make-up water supply stop water level that stops the supply of make-up water to be supplied as described later. The third control water level L3 is the make-up water supply start water level at which the make-up water supply is started. The fourth controlled water level L4 is a water level at which it becomes difficult to pump the reformed water by the reformed water pump 11b2.

The control device 16 drives an auxiliary machine including the radiator 22b, the three-way valve 22d, and the water supply valve 22g described above to control the operation of the fuel cell system 1 in an integrated manner. The control device 16 has a microprocessor (not shown). The microcomputer includes an input / output interface, a CPU, a RAM, a ROM, and a timer (all of which are not shown) connected via a bus. The CPU carries out the integrated operation of the fuel cell system 1. The RAM temporarily stores variables necessary for executing various programs including the make-up water supply control program described later, and the ROM stores various programs including the make-up water supply control program described later.

Further, 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 made of a heat insulating material and is formed in a box shape. The evaporation unit 32 is heated by a combustion gas described later to evaporate the supplied reforming water to generate steam, and preheats the supplied reforming raw material. The evaporation unit 32 mixes the steam generated in this manner with the preheated reforming raw material and supplies it to the reforming unit 33.

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

The reforming unit 33 is heated by a combustion gas described later and is supplied with the heat required for the steam reforming reaction, so that the reforming unit 33 contains steam from the mixed gas (raw material for reforming, steam) supplied from the evaporating unit 32. A reformed gas (anode gas) is generated and derived from the reformed gas delivery pipe 38. The reforming unit 33 is filled with a catalyst (for example, a Ru or Ni-based catalyst), and the mixed gas reacts with the catalyst to reform and generate a gas containing hydrogen gas, carbon monoxide, and the like. (Steam reforming reaction). The reforming gas includes hydrogen, carbon monoxide, carbon dioxide, water vapor, unmodified natural gas (methane gas), and reformed water (steam) that was not used for reforming. In this way, the reforming unit 33 generates a reforming gas (fuel) from the reforming raw material (raw fuel) and the reforming water, and supplies the reforming gas to the fuel cell 34. The steam reforming reaction is an endothermic reaction.

The fuel cell 34 is configured by stacking a plurality of cells 34a composed of a fuel electrode, an air electrode (oxidizing agent electrode), and 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 to 1000 ° C. It should be noted that even at 400 ° C. or lower, it is possible to generate a power generation amount below the rating. In addition, the start of power generation is permitted at 600 ° C. Not only hydrogen but also natural gas, coal gas and the like can be directly used as fuel. In this case, the modification unit 33 can be omitted.

A fuel flow path 34b through which a reformed gas (anode gas), which is a fuel, flows is formed on the fuel electrode side of the cell 34a. An air flow path 34c through which air (cathode air), which is an oxidizing agent 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. The reforming gas (anode gas) from the reforming section 33 is supplied to the manifold 35 via the reforming 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 derived from the fuel outlet is introduced from the lower end and led out from the upper end. .. The cathode air delivered by the cathode air blower 11c1 is supplied through the cathode air supply pipe 11c, is introduced from the lower end of the air flow path 34c, and is 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 by the cathode air blower 11c1. The flow rate sensor 11c3 transmits the detection result to the control device 16.

In the fuel cell 34, power generation is performed by the reforming gas (anode gas) which is the fuel supplied to the fuel electrode and the oxidant gas (cathode gas) supplied to the air electrode. That is, at the fuel electrode, the reactions shown in Chemical formulas 1 and 2 below occur, and at the air electrode, the reactions shown in Chemical formula 3 below occur. Specifically, oxide ions ( ^O2- ) generated at the air electrode permeate the electrolyte and react with hydrogen at the fuel electrode to generate electrical energy. Then, the reforming gas and the oxidant gas that were not 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 1)
H ₂ + O ^2- → H ₂ O + 2e ⁻
(Chemical 2)
CO + O ^2- → CO ₂ + 2e ⁻
(Chemical 3)
^{_{1 / 2O 2 + 2e - →}} O 2-

The reformed gas (anode off gas as the fuel off gas) not used for power generation is led out from the fuel flow path 34b to the combustion section 36 (the space formed between the fuel cell 34 and the reforming section 33). Similarly, the oxidant gas (air: cathode off gas) that was not used for power generation is led out from the air flow path 34c to the combustion unit 36. In the combustion unit 36, the anode off gas is burned by the cathode off gas, and the evaporation gas (flame 37) heats the evaporation unit 32 and the reforming unit 33. Further, 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. The flue 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 the water generated in the fuel cell 34 by the electrochemical reaction.

When activating the fuel cell system 1, the control device 16 executes the warm-up mode prior to the power generation mode. In the warm-up mode, the control device 16 drives the raw material pump 11a1 to feed the reforming raw material via the reforming raw material supply pipe 11a via the evaporation unit 32, the reforming unit 33, and the fuel cell 34 of the fuel cell module 11. Is supplied to the combustion unit 36. The control device 16 also drives the cathode air blower 11c1 to supply 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. .. Then, when the ignition heaters 36a1 and 36a2 are ignited, the reforming raw material is burned by air in the combustion unit 36. The combustion heat in the combustion unit 36 heats the evaporation unit 32, the reforming unit 33, and the fuel cell 34. 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. Exit 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 evaporation unit 32 to become steam. The steam moves to the reforming unit 33 together with the reforming raw material supplied from the reforming raw 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) which is a reforming gas containing steam (endothermic reaction). The anode gas is supplied to the fuel electrode of the cell 34a of the fuel cell 34 via the fuel flow path 34b. Further, the cathode air blower 11c1 is driven, and the cathode gas (air) is supplied to the electric pole of the cell 34a via the air flow path 34c. As a result, the fuel cell 34 (fuel cell module 11) generates electricity.

In the warm-up 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. Will be done. Since the water vapor contained in the high-temperature combustion exhaust gas is cooled by the heat exchanger 12, it is condensed into condensed water, and the water generated in the fuel cell 34 by the electrochemical reaction is passed through the condensed water supply pipe 12a. Is supplied to the reformed water tank 15.

The housing 10a has an intake port 10b for sucking in outside air, a ventilation exhaust port 10c for discharging the air inside the housing 10a to the outside, and a combustion exhaust gas from the heat exchanger 12 to the outside. The 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 regulates 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 tap water is measured by a water temperature measuring device 67 provided in the water supply pipe 42, for example, a thermistor, and output to the control device 16. The hot water storage tank 21 stores, for example, hot water adjusted to 70 ° C., which is generated by being warmed by the exhaust heat recovery by the hot water storage water circulation line 22 described above.

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

As shown in FIG. 1, a normally open electromagnetic on-off valve 65 that is opened when the power is not supplied is provided in the bypass passage 64 that connects the water supply pipe 42 to the mixed hot water supply pipe 63. The electromagnetic on-off valve 65 cannot be mixed (controlled) with hot water and water due to, for example, a failure of the control system of the mixing valve 62 or the mixing valve 62, and the temperature of the mixed hot water in the mixing hot water supply pipe 63 rises and is preset. When the upper limit temperature of the mixed hot water (for example, 50 ° C.) is exceeded, the control device 16 switches to the open state. By opening the electromagnetic on-off valve 65 and guiding water from the water supply pipe 42 to the mixed hot water supply pipe 63, the temperature of the mixed hot water in the mixed hot water supply pipe 63 is lowered, and abnormally high temperature hot water discharge is prevented. The temperature of the mixed hot water is measured by a hot water temperature measuring device 66 provided on the downstream side of the confluence portion of the mixed hot water supply pipe 63 with the bypass passage 64, for example, a thermistor, and is output to the control device 16.

By the way, as described above, when the fuel cell module 11 generates electricity, the reformed water is indispensable in order to generate the reformed gas (anode gas) in the reforming unit 33. Therefore, it is necessary that an appropriate amount of reformed water is stored in the reformed water tank 15 so that the reformed water can be supplied to the reforming unit 33. Therefore, the control device 16 (more specifically, the CPU) executes the make-up water supply control program shown in FIG. 2, and reforms water according to the amount of reformed water stored in the reformed water tank 15. Circulating water is supplied to the reforming water tank 15 when there is a risk of interfering with the supply of the water. Hereinafter, this make-up water supply control program will be described in detail.

The control device 16 starts executing the make-up water supply control program in step S100 every time a predetermined short time elapses, and in the following step S101, the third control water level which is the make-up 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 a predetermined time t1 or more, that is, when the water level drop in the reforming water tank 15 is confirmed and it is necessary to start the supply of make-up water. , It is determined as "Yes" in step S101, and the process proceeds to step S102. On the other hand, if the control device 16 has not continuously acquired the signal Ss for a predetermined time t1 or more, the control device 16 determines "No" and proceeds to step S113 to temporarily end the execution of the make-up water supply control program. Then, when the predetermined short time elapses, the execution of the make-up water supply control program is started again in step S100.

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

In step S103, in the control device 16, the first temperature T1 of the hot water stored water flowing through the hot water storage water supply pipe 22e from the first temperature sensor 22c is less than the first predetermined temperature Td1 (less than the first predetermined temperature), and , It is determined whether or not this state continues for the first predetermined time t2 or more (continues for the first predetermined time or more). Here, the first predetermined temperature Td1 is set to, for example, a temperature at which the ion exchange resin constituting the water purifier 14 does not cause thermal deterioration. Further, the first predetermined time t2 is set longer than the predetermined time t1.

If the first temperature T1 is lower than the first predetermined temperature Td1 and this state continues for the first predetermined time t2 or more, the control device 16 determines "Yes" in step S103 and proceeds to step S104. move on. On the other hand, in the control device 16, the time when the first temperature T1 is equal to or higher than the first predetermined temperature Td1 or the time when the first temperature T1 is lower than the first predetermined temperature Td1 during cooling by the radiator 22b is the second. If it is less than t2 for a predetermined time, 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 hot water storage water, "No" is displayed in step S103. The determination is made and the process proceeds to step S107.

In step S104, the control device 16 supplies the entire amount of the hot water stored in the hot water supply pipe 22e to the heat exchanger 12, and then uses a part (about several%) of the hot water as make-up water in the reformed water tank 15. The valve opening degree of the three-way valve 22d is adjusted (changed) so as to supply to. When the three-way valve 22d is opened, 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 the hot water storage water to the heat exchanger 12 is referred to as a "fully closed state", and a part of the hot water storage water is reformed as make-up water. The state of the valve opening degree of the three-way valve 22d supplied to the water tank 15 is referred to as an "open state".

In this way, when the three-way valve 22d is opened, the make-up water whose first temperature T1 is lower than the first predetermined temperature Td1 flows toward the make-up water supply pipe 22f. The make-up water supply pipe 22f is adjusted by lowering the water pressure of the make-up water that has flowed in (falls) by the pressure loss portion 22f1 (U-shaped portion), and the make-up water for which the water pressure has been adjusted flows 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. As a result, the make-up water is supplied to the water purifier 14, and the water purifier 14 purifies the make-up water and supplies it to the reformed water tank 15.

In step S105, the control device 16 has a signal Sf indicating the second control water level L2, which is the water level at which the make-up water supply is stopped from the water level sensor 15d, with respect to the water level of the reforming water tank 15 to which the make-up water is supplied as described above. Is determined. That is, the control device 16 determines whether or not to stop the supply of make-up water based on the water level of the reforming water tank 15 to which the make-up 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. In other words, the reforming water tank 15. When the water level reaches the second control water level L2 that stops the supply of make-up water, it is determined as "Yes" 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 the fully closed state. As a result, the supply of make-up water from the hot water storage water supply pipe 22e via the make-up water supply pipe 22f is stopped, and the entire amount of the hot water storage water flowing through the hot water storage water supply pipe 22e is supplied to the heat exchanger 12. When the control device 16 controls the three-way valve 22d to the fully closed state, 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 the fully closed state.

On the other hand, when the control device 16 determines "No" in step S103, that is, when it is necessary to further cool the hot water stored water flowing through the hot water storage 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", which represents a state in which the radiator 22b is operated with a cooling capacity higher than the normal cooling capacity. As a result, the control device 16 operates the radiator 22b with a cooling capacity higher 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 stored in the hot water storage pipe 22e. Improve your ability. Specifically, in the power control for supplying power (current) to the motor of the radiator 22b, the control device 16 increases, for example, the duty ratio Dr of the power supply by a predetermined value α with respect to the duty ratio Dr1 during normal operation. .. That is, the control device 16 supplies the motor with electric power (current) having a duty ratio Dr (= Dr1 + α). As a result, the radiator 22b increases the cooling capacity as the rotation speed of the fan increases, and cools the hot water stored water flowing through the hot water storage water supply pipe 22e. In this way, the control device 16 proceeds to step S109 when the cooling capacity of the radiator 22b is increased.

In step S109, in the control device 16, similarly to step S103, the first temperature T1 of the hot water storage water flowing from the first temperature sensor 22c to the hot water storage water supply pipe 22e is less than the first predetermined temperature Td1. , It is determined whether or not this state continues for the first predetermined time t2 or more. Specifically, the control device 16 continues to determine "No" in step S109 until the first temperature T1 is less than the first predetermined temperature Td1 and this state continues for the first predetermined time t2 or more.

Then, when the first temperature T1 is lower than the first predetermined temperature Td1 and this state continues for the first predetermined time t2 or more, that is, the radiator 22b is operated to operate the first temperature of the hot water stored in the control device 16. If it is no longer necessary to cool T1, it is determined as "Yes" in step S109, and the process proceeds to step S104. When the hot water stored water flowing through the hot water storage water supply pipe 22e is cooled in this way, the control device 16 executes each step process 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 or not 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 make-up water supply control program. In this case, since the radiator 22b is operated by the normal cooling capacity, the control device 16 operates the radiator 22b as it is. Then, when the predetermined short time elapses, the control device 16 starts executing the make-up water supply control program again in step S100.

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, by the step process of step S108, the control device 16 operates the radiator 22b with a cooling capacity higher than the normal cooling capacity. Therefore, the control device 16 executes each step process after step S111 to operate the radiator 22b with a normal cooling capacity.

In step S111, the control device 16 sets the duty ratio Dr (= Dr1 + α) of the electric power (current) supplied to the motor of the radiator 22b to the duty during normal operation according to the operation flag P being “1”. Change (return) to the ratio Dr1. Specifically, the control device 16 subtracts a predetermined value α from the duty ratio Dr, changes the duty ratio to Dr1 during normal operation, and proceeds to step S112. As a result, 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 make-up water supply control program. Then, when the predetermined short time elapses, the control device 16 starts executing the make-up water supply control program again in step S100.

As can be understood from the above description, according to the fuel cell system 1 of the above embodiment, the fuel cell 34 that generates power by the fuel and the oxidizing agent gas, the reforming raw material, and the steam vapor obtained by evaporating the reforming water. A reforming unit 33 that generates fuel from the water and supplies the fuel to the fuel cell 34, and a reforming unit that is provided in the reforming raw material supply pipe 11a connected to the supply source Gs of the reforming raw material and is provided from the supply source Gs. A raw material pump 11a1 as a reforming raw material supply device for pumping the reforming raw material to 33, and a reforming water tank 15 for storing 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 oxidizing agent gas (cathode off gas) from the fuel cell 34 and the circulating water supplied from the hot water storage tank 21 via the hot water storage water supply pipe 22e. The condensed water supply pipe 12a that connects the heat exchanger 12 as a condenser that exchanges heat and condenses the water vapor contained in the combustion exhaust gas to generate condensed water, and the reformed water tank 15 and the heat exchanger 12. A water purifier 14 provided in the water purifying water to purify the condensed water and supplying the reformed water to the reformed water tank 15, and a radiator provided in the hot water storage water supply pipe 22e to cool the circulating water supplied from the hot water storage tank 21. A fuel cell system including a 22b and a control device 16 that controls and controls the power generation of the fuel cell 34, and is provided between the heat exchanger 12 of the hot water storage water supply pipe 22e and the radiator 22b. The circulating water supply amount of the circulating water flowing to the heat exchanger 12 side and the make-up water supply amount of the make-up water separated from the circulating water and flowing to the reforming water tank 15 side can be adjusted according to the control by the control device 16. The first temperature T1 of the circulating water provided between the three-way valve 22d as a proper adjusting valve and the three-way valve 22d of the hot water storage water supply pipe 22e and the radiator 22b and passing through the radiator 22b is detected, and the first temperature T1 is set. A first temperature sensor 22c that outputs to the control device 16, a make-up water supply pipe 22f that connects the three-way valve 22d and the water purifier 14 to supply make-up water from the three-way valve 22d to the water purifier 14, and a water purifier. The first control water level L1, the second control water level L2, the third control water level L3, and the fourth control water level L4 are set as the water levels in which the reformed water generated from the condensed water and the make-up water by 14 is stored in the reformed water tank 15. Reform of make-up water from the hot water storage tank 21 including a water level sensor 15d that detects and outputs the first control water level L1, the second control water level L2, the third control water level L3, and the fourth control water level L4 to the control device 16. A make-up water adjusting unit 70 for adjusting the supply to the water tank 15 is provided. Then, when the water level detected by the water level sensor 15d becomes the third control water level L3 which is the preset make-up water supply start water level, the control device 16 detects the circulating water by the first temperature sensor 22c. When the first temperature T1 becomes less than the preset first predetermined temperature Td1 (less than the first predetermined temperature), the amount of make-up water supplied by the three-way valve 22d is increased from zero to the make-up water supply pipe 22f and water purification. When the make-up water is supplied to the reforming water tank 15 via the vessel 14 and the water level detected by the water level sensor 15d becomes the second control water level L2 which is the preset make-up water supply stop water level, the three sides It is configured to return the amount of make-up water supplied by the valve 22d to zero.

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

Further, the make-up water adjusting unit 70 is a hot water storage water (circulating water) flowing through the hot water storage water supply pipe 22e by a three-way valve 22d provided in the hot water storage water supply pipe 22e that supplies the circulating water from the hot water storage tank 21 to the heat exchanger 12. Part of the water can be separated as make-up water, and the reformed water purified from the make-up water by the water purifier 14 can be supplied to the reformed water tank 15. As a result, for example, it is not necessary 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 have a simple configuration and the dedicated supply pipe. It is possible to reduce the cost for providing the above.

Further, the make-up water adjusting unit 70 can use a part of the hot water storage water (circulating water) supplied from the hot water storage tank 21 as make-up water. In this case, the hot water stored in the hot water storage tank 21 (circulating water) is temporarily heated to a relatively high temperature by heat exchange with the heat exchanger 12 while impurities are removed by a strainer or the like. As a result, the hot water storage water (circulating water) is simply dechlorinated, and even when the make-up water separated from the hot water storage water (circulating water) is supplied to the water purifier 14, the ions are ionized. The load when the replacement resin purifies the make-up water can be reduced. As a result, the expensive water purifier 14 (ion exchange resin) can be miniaturized, and the fuel cell system 1 as a whole can be miniaturized and the cost can be reduced.

In this case, the control device 16 continues for a preset first predetermined time t2 or more (continues for the first predetermined time or more) in a state where the first temperature T1 is lower than the first predetermined temperature Td1 (less than the first predetermined temperature). If so, the amount of make-up water supplied by the three-way valve 22d is increased from zero.

According to this, when the first temperature T1 of the hot water (circulating water), that is, the first temperature T1 of the make-up water is surely lower than the first predetermined temperature Td1, the three-way valve 22d is transferred to the water purifier 14. It can supply make-up water. As a result, it is possible to effectively prevent the ion exchange resin of the water purifier 14 from being thermally deteriorated by the make-up water. Therefore, the frequency of replacement of the expensive ion exchange resin can be significantly 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 increases the cooling efficiency of cooling the circulating water of the radiator 22b when the first temperature T1 is the first predetermined temperature Td1 or higher (the first predetermined temperature or higher). To operate.

According to this, when the first temperature T1 is the first predetermined temperature Td1 or more (the first predetermined temperature or more), the control device 16 increases the cooling efficiency of the radiator 22b and moves from the hot water storage tank 21 to the heat exchanger 12. The first temperature T1 of the hot water storage water (circulating water), that is, the make-up water flowing through the hot water storage water supply pipe 22e can be rapidly lowered. As a result, it is possible to effectively prevent the ion exchange resin of the water purifier 14 from being thermally deteriorated by the make-up water.

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

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

(Modification example)
In the above embodiment, in the control device 16, the first temperature T1 of the hot water stored in the hot water supply pipe 22e is 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 reached a temperature at which deterioration did not occur, the three-way valve 22d was opened and the make-up water was supplied (supplemented) to the reformed water tank 15. In this case, it is possible to more reliably prevent the thermal deterioration of the water purifier 14 from occurring. Hereinafter, this modification will be described, but a detailed description will be made focusing on a portion different from the above embodiment.

This modification is different from the above embodiment in that the second temperature sensor 22h is arranged between the make-up water supply pipe 22f and the water supply valve 22g as shown in FIG. 4 in terms of configuration. That is, in this modification, the second temperature sensor 22h is included in the make-up water adjusting unit 70. The second temperature sensor 22h detects the temperature T2 of the make-up water supplied from the three-way valve 22d and flows through the make-up water supply pipe 22f (hereinafter, referred to as “second temperature T2”) and transmits it to the control device 16. ing. Further, in this modification, the control device 16 controls the opening or closing of the water supply valve 22g based on the second temperature T2 acquired from the second temperature sensor 22h.

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

In this modification, when the control device 16 controls the three-way valve 22d in the open state in step S104, the control device 16 proceeds to step S120. In step S120, in the control device 16, the second temperature T2 of the make-up water supplied from the second temperature sensor 22h to the make-up water supply pipe 22f is less than the second predetermined temperature Td2 (less than the second predetermined temperature), and , It is determined whether or not this state continues for the second predetermined time t3 or more (continues for the second predetermined time or more). Here, the second predetermined temperature Td2 is set to, for example, a temperature at which the ion exchange resin constituting the water purifier 14 does not cause thermal deterioration. Further, the second predetermined time t3 is set longer than the predetermined time t1.

Specifically, the control device 16 continues to determine "No" in step S120 until the second temperature T2 is less than the second predetermined temperature Td2 and this state continues for the second predetermined time t3 or more. Then, if 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 control device 16 determines "Yes" in step S120. The process proceeds to step S121. That is, when the second temperature T2 is less than the second predetermined temperature Td2 and this state continues for the second predetermined time t3 or more, the second temperature T2 of the make-up water supplied to the make-up water supply pipe 22f becomes. The second predetermined temperature is definitely less than Td2. Therefore, even if the make-up water is supplied to the water purifier 14 from the water supply valve 22 g, it is possible to suppress thermal deterioration of the ion exchange resin of the water purifier 14.

In step S121, the control device 16 switches the water supply valve 22g from closed to open. As a result, the make-up water supplied to the make-up water supply pipe 22f is supplied to the water purifier 14 via the water supply valve 22g. Therefore, the water purifier 14 purifies the make-up water and supplies it to the reformed water tank 15.

As described above, the control device 16 switches the water supply valve 22g to open in step S121, and then determines the water level of the reforming water tank 15 to which the make-up 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 control water level L2, which is the make-up water supply stop water level that stops the supply of make-up water, the step. It is determined as "Yes" in S105, and the process proceeds to step S122.

In step S122, the control device 16 switches the water supply valve 22g, which was switched to open in step S121, to close, and proceeds to step S106. As a result, even if the three-way valve 22d is in the open state and the make-up water supply pipe 22f is supplied with make-up water, the water supply valve 22g is switched to the closed state, so that the make-up water purifier 14 and the reformed water tank The supply to 15 is stopped. Then, in the step S106, the control device 16 controls the three-way valve 22d opened in the step S104 to the fully closed state. As a result, the supply of make-up water from the hot water storage water supply pipe 22e is stopped, and the entire amount of the hot water storage water flowing through the hot water storage 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 make-up water adjusting unit 70 is provided in the make-up water supply pipe 22f to supply make-up water. The second temperature sensor 22h that detects the second temperature T2 of the make-up water flowing through the pipe 22f and outputs the second temperature T2 to the control device 16, and the water purifier 14 and the second temperature sensor 22h of the make-up water supply pipe 22f. A control device including a water supply valve 22g, which is provided between the water supply valves 22g to allow the flow from the make-up water supply pipe 22f of the make-up water to the water purifier 14 to be open or to shut off the flow according to the control by the control device 16. Reference numeral 16 denotes a continuation of the preset second predetermined time t3 or more in a state where the second temperature T2 detected by the second temperature sensor 22h is less than the preset second predetermined temperature Td2 (less than the second predetermined temperature). (Continued for the second predetermined time or longer), the water supply valve 22g is switched to open to allow the supply of make-up water from the make-up water supply pipe 22f to the reforming water tank 15 via the water purifier 14, and the water level sensor. When the water level detected by 15d reaches the third control water level L3, the water supply valve 22g is switched to close and the make-up water is shut off from the make-up water supply pipe 22f toward the reforming water tank 15 via the water purifier 14. It is configured to do.

According to this, the water supply valve 22g is switched from closed to open after the second temperature T2 detected by the second temperature sensor 22h becomes less than the second predetermined temperature Td2. Therefore, for example, even if an error occurs in the first temperature T1 detected by the first temperature sensor 22c, the second temperature T2 of the make-up water flowing through the make-up water supply pipe 22f downstream of the three-way valve 22d can be set. The second temperature sensor 22h can detect and control the opening and closing of the water supply valve 22g according to the second temperature T2. Therefore, it is possible to reliably prevent the ion exchange resin of the water purifier 14 from being erroneously supplied with high-temperature make-up water that causes thermal deterioration. As for other effects, the same effects as those in the above embodiment can be obtained.

The implementation of the present invention is not limited to the above-described embodiment and the above-mentioned modification, and various modifications are possible as long as the object of the present invention is not deviated.

For example, in the above embodiment and the above modification, the make-up water adjusting unit 70 causes a pressure loss in the make-up water supplied from the three-way valve 22d in the open state to reduce the water pressure, so that the make-up water supply pipe 22f has a U-shape. It has a pressure drop portion 22f1 bent in a shape. Instead of this, as shown in FIG. 6, it is also possible to provide a pressure loss portion 22f2 formed of a throttle (orifice) between the three-way valve 22d and the water supply valve 22g. Even when the pressure loss portion 22f2 is provided, the make-up water supplied from the three-way valve 22d can be pressure-damaged to reduce the water pressure of the make-up water, so that the water is supplied to the water purifier 14 via the water supply valve 22g. The water pressure of the 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 the high water pressure, and as a result, the replacement frequency of the expensive water purifier 14 can be suppressed and the running cost of the fuel cell system 1 can be reduced. Can be done.

Further, in the above embodiment and the modified example, the water level sensor 15d is a float type sensor. Instead of this, the water level sensor 15d may be a widely known capacitance type or pressure type sensor. Even in this case, the water level sensor 15d can detect the first controlled water level L1 to the fourth controlled water level L4 as the water level of the reformed water stored in the reformed water tank 15 and transmit it to the control device 16. Therefore, the same effect as that of the above embodiment and the above modification can be obtained.

Further, in the above-described embodiment and the above-mentioned modification, the radiator 22b is assumed to be an air-cooled type. Instead of this, it is also possible to use a water-cooled radiator, another heat radiating device, or a heat transfer device as the radiator 22b.

Further, in the above embodiment and the above modification, in the step S108 in the make-up water supply control program shown in FIGS. 3 and 5, the control device 16 sets the rotation speed of the motor and the fan in order to increase the cooling capacity of the radiator 22b. I tried to increase it. In this case, it is also possible to increase the rotation speeds of the motor and the fan stepwise to prevent the operating noise of the radiator 22b from leaking to the outside of the housing 10a.

Further, in the above embodiment and the above modification, the control device 16 supplies make-up water when the water level of the reforming water in the reforming water tank 15 reaches the second control water level L2 during the power generation operation of the fuel cell system 1. Then, when the reformed water level reached the third control water level L3, the supply of make-up water was stopped. That is, in the above embodiment and the above modification, during the power generation operation of the fuel cell system 1, the water level of the reforming water 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 existed in between.

By the way, when the fuel cell system 1 is out of power generation operation and the water level of the reforming water exists between the second controlled water level L2 and the third controlled water level L3 of the reformed water tank 15, the next fuel In preparation for the power generation operation of the battery system 1, the control device 16 previously 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. It is also possible to supply to 15. As a result, in the next power generation operation of the fuel cell system 1, for example, the warm-up mode can be quickly shifted to the power generation mode, and the fuel cell system 1 can be started quickly. However, in this case, the condition is that the first temperature T1 of the hot water stored in the hot water storage 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 (replenishes) hot water (replenishment water) to the reforming water tank 15.

1 ... Fuel cell system, 10 ... Power generation unit, 10a ... Housing, 10b ... Intake port, 10c ... Ventilation exhaust port, 10d ... Combustion exhaust gas exhaust port, 11 ... Fuel cell module, 11a ... Raw material supply pipe for reforming , 11a1 ... Raw material pump, 11b ... Reforming water supply pipe, 11b2 ... Reforming water pump, 11c ... Cone air supply pipe, 11c1 ... Cone air blower, 11c2 ... Electric motor, 11c3 ... Flow sensor, 11d ... Exhaust pipe, 12 ... Heat exchanger (condenser), 12a ... Condensed water supply pipe, 12b ... Drain pipeline, 13 ... Inverter device, 14 ... Water purifier, 15 ... Modified 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 storage tank, 22 ... hot water storage water circulation line, 22a ... Hot water storage water circulation pump, 22b ... Radiator, 22c ... First temperature sensor, 22d ... Three-way valve (regulatory valve), 22e ... Hot water storage pipe, 22f ... Makeup water supply pipe, 22f1 ... Pressure loss part, 22f2 ... Pressure loss part, 22g ... Water supply valve, 22h ... Second temperature sensor, 31 ... Casing, 32 ... Evaporation part, 33 ... Modification 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 ... Modified gas delivery pipe, 41 ... Pressure reducing valve, 42 ... Water supply 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 measuring device, 67 ... water temperature measuring device, 69 ... hot water tap, 70 ... make-up water adjustment unit, Dr ... duty ratio, Dr1 ... duty ratio, Gs ... supply source, L1 ... first control water level, L2 ... second control water level (make-up water supply stop water level), L3 ... third control water level ( Makeup water supply stop water level), L4 ... 4th control water level, P ... operation flag, Sw ... high pressure water supply source, 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 ... water heater, α ... predetermined value

Claims (5)

Fuel cells that generate electricity from fuel and oxidant gas,
A reforming unit that generates the fuel from the reforming raw material and steam obtained by evaporating the reforming water and supplies the fuel to the fuel cell.
A reforming raw material supply device provided in a reforming raw material supply pipe connected to the supply source of the reforming raw material and pumping the reforming raw material from the supply source to the reforming portion.
A reformed water tank for storing the reformed water supplied to the reformed portion via a reformed water supply pipe, and
It is contained in the combustion exhaust gas by exchanging heat between the combustion exhaust gas generated by burning the fuel off gas and the oxidant gas from the fuel cell and the circulating water supplied from the hot water storage tank via the hot water storage water supply pipe. A condenser that condenses the water vapor to generate 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 provided in the hot water storage pipe to cool the circulating water supplied from the hot water storage tank, and
A fuel cell system including a control device that controls the power generation of the fuel cell.
The circulating water supply amount of the circulating water which is provided between the condenser and the radiator of the hot water storage pipe and flows to the side of the condenser, and the circulating water supply amount of the circulating water which is separated from the circulating water of the reformed water tank. An adjustment valve that can adjust the amount of make-up water supply of make-up water flowing to the side according to the control by the control device,
A first temperature sensor provided between the regulating valve of the hot water storage pipe and the radiator, detects the first temperature of the circulating water that has passed through the radiator, and outputs the first temperature to the control device. When,
A make-up water supply pipe that connects the regulating valve and the water purifier to supply the make-up water from the regulating valve to the water purifier.
The water level sensor includes a water level sensor that detects the water level stored in the reformed water tank by the condensed water and the reformed water generated from the make-up water by the water purifier and outputs the water level to the control device. A make-up water adjusting unit for adjusting the supply of the make-up water from the hot water storage tank to the reformed water tank is provided.
The control device is
When the water level detected by the water level sensor reaches the preset make-up water supply start water level,
When the first temperature of the circulating water detected by the first temperature sensor becomes lower than the preset first predetermined temperature, the supply amount of the make-up water by the adjusting valve is increased from zero to make the replenishment. The make-up water is supplied to the reformed water tank via the water supply pipe and the water purifier.
A fuel cell system configured to return the make-up water supply amount by the regulating valve to zero when the water level detected by the water level sensor reaches a preset make-up water supply stop water level. The control device is
When the first temperature is lower than the first predetermined temperature and continues for a preset first predetermined time or longer,
The fuel cell system according to claim 1, wherein the amount of the make-up water supplied by the regulating valve is increased from zero. The control device 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 the cooling efficiency for cooling the circulating water of the radiator is increased. The make-up water adjusting unit
A second temperature sensor provided in the make-up water supply pipe, detecting the second temperature of the make-up water flowing through the make-up water supply pipe, and outputting the second temperature to the control device.
It is 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 block the flow. A water supply valve that switches the closing according to the control by the control device is provided.
The control device is
When the second temperature detected by the second temperature sensor is lower than the preset second predetermined temperature and continues for a preset second predetermined time or longer.
The water supply valve is switched to open to allow the supply of the make-up water from the make-up water supply pipe to the reformed water tank via the water purifier.
When the water level detected by the water level sensor reaches the make-up water supply stop water level, the water supply valve is switched to close and the make-up water supply pipe is directed toward the reformed water tank via the water purifier. The fuel cell system according to any one of claims 1 to 3, which is configured to shut off the make-up water. The make-up water supply pipe
The fuel cell system according to any one of claims 1 to 4, further comprising a pressure loss portion that causes pressure loss in the make-up water flowing from the regulating valve toward the water purifier.

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