JP7540969B2 - Fuel cell system, control device, and control program - Google Patents

Description

This disclosure relates to a fuel cell system, a control device, and a control program, and more particularly to a fuel cell system, a control device, and a control program capable of supplying electric power and hot water.

Conventional drainage methods for fuel cell systems include the overflow method (a method in which drain water is discharged by overflowing) and the pump delivery method (a method in which drain water is discharged using a drainage pump). By using these two drainage methods, excess drain water is discharged to the outside by overflowing (see, for example, Patent Document 1).

JP 2019-083177 A

The conventional technology described in Patent Document 1 has an overflow system as a backup for the pump discharge system, so excess drain water can be made to overflow and discharged to the outside.

On the other hand, depending on the installation area and location of the fuel cell system and the season in which it is in operation, there are cases where the external drainage piping freezes. In addition to the pump delivery method, a gravity flow method, which drains water by natural flow without using a pump, can be used to drain water through the external drainage piping. In addition to this, an overflow method, which drains water directly to the outside without going through a drainage piping, may be used as a backup. In this way, the system will not break down even if the drainage piping becomes blocked due to freezing.

However, depending on the system, the system may determine that an abnormality exists because the drainage pipes are frozen and the system is unable to drain water, causing the system to shut down due to an error (hereafter referred to as a "drainage abnormality error"). For safety reasons, this drainage abnormality error is usually designed in such a way that the user cannot reset it, resulting in a loss of power generation opportunities and requiring the dispatch of maintenance personnel.

The present disclosure has been made in consideration of the above circumstances, and aims to provide a fuel cell system, control device, and control program that can avoid the need to dispatch maintenance personnel without losing power generation opportunities when a drainage abnormality error occurs in a low-temperature environment.

To achieve the above object, the fuel cell system according to the first aspect includes a fuel cell module that generates electricity, a reforming water tank including a reforming water storage section that stores water obtained from exhaust gas discharged from the fuel cell module as reforming water to be introduced into the fuel cell module, a drainage storage section that is provided within the reforming water tank and that stores water that has overflowed from the reforming water storage section and is connected to a first drainage channel and a drainage pipe that discharge the stored water to the outside, a surplus storage section that is provided within the reforming water tank and that is connected to a second drainage channel that directly discharges water that has overflowed from the drainage storage section to the outside, and a control device that includes a control unit that detects a drainage abnormality error and, when a condition indicating that the temperature of the external environment is relatively low is met, disables the shutdown of the system and controls to continue power generation.

The fuel cell system according to the second aspect is the fuel cell system according to the first aspect, further comprising a housing that houses the fuel cell module, the reforming water tank, and the control device, the first drainage channel and the second drainage channel being provided within the housing, and the drainage pipe being provided outside the housing and connected to the drainage storage section via the first drainage channel.

The fuel cell system according to the third aspect is the fuel cell system according to the first or second aspect, further including an acquisition unit that acquires the air temperature measured around the fuel cell unit in which the fuel cell module is installed when the control device detects the drainage abnormality error, and the condition indicating that the temperature of the external environment is relatively low includes the air temperature being equal to or lower than a threshold value.

In addition, the fuel cell system according to the fourth aspect is the fuel cell system according to the first or second aspect, further including an acquisition unit that acquires weather information for the area in which the system is installed when the control device detects an error of the drainage abnormality, and the condition indicating that the temperature of the external environment is relatively low includes the air temperature acquired from the weather information being equal to or lower than a threshold value.

The fuel cell system according to the fifth aspect is the fuel cell system according to the first or second aspect, further comprising an acquisition unit that acquires calendar information indicating the time when the control device detects the drainage abnormality error, and the condition indicating that the temperature of the external environment is relatively low includes the time obtained from the calendar information being a relatively low temperature period.

The fuel cell system according to the sixth aspect is the fuel cell system according to any one of the first to fifth aspects, further comprising a drainage pump provided in the first drainage channel, and the drainage method of the drainage storage section is a pump delivery method in which drainage is performed using the drainage pump.

The fuel cell system according to the seventh aspect is the fuel cell system according to any one of the first to fifth aspects, in which the drainage method of the drainage storage section is a gravity flow method in which the drainage is performed under natural flow.

Furthermore, in order to achieve the above object, the control device according to the eighth aspect is a control device that controls the operation of a fuel cell system including a fuel cell module that generates electricity, a reforming water tank including a reforming water storage section that stores water obtained from exhaust gas discharged from the fuel cell module as reforming water to be introduced into the fuel cell module, a drainage storage section that is provided in the reforming water tank and that stores water that overflows from the reforming water storage section and is connected to a first drainage channel and a drainage pipe that discharge the stored water to the outside, and a surplus storage section that is provided in the reforming water tank and that is connected to a second drainage channel that directly discharges water that overflows from the drainage storage section to the outside, and includes a control unit that detects a drainage abnormality error and, when a condition indicating that the temperature of the external environment is relatively low is met, disables the stop of the system and controls to continue power generation.

Furthermore, in order to achieve the above object, the control program according to the ninth aspect causes a computer to function as a control unit provided in a control device according to any one of the first to seventh aspects.

As described above in detail, the technology disclosed herein has the effect of preventing the dispatch of maintenance personnel when a drainage abnormality error occurs in a low-temperature environment without losing the opportunity to generate electricity.

1 is a diagram showing an example of the configuration of a fuel cell system according to a first embodiment; 1 is a diagram showing an example of the configuration of a fuel cell module according to a first embodiment; FIG. 4 is a diagram showing an example of a drainage configuration of a reforming water tank according to the first embodiment; FIG. 2 is a block diagram showing an example of an electrical configuration of a control device according to the first embodiment. FIG. 2 is a block diagram showing an example of a functional configuration of a control device according to the first embodiment. 5 is a flowchart showing an example of a process flow according to a control program according to the first embodiment. FIG. 11 is a diagram showing an example of a drainage configuration of a reforming water tank according to a second embodiment. FIG. 11 is a diagram showing an example of a drainage configuration of a reforming water tank according to a second embodiment.

An example of a form for implementing the technology of the present disclosure will be described in detail below with reference to the drawings. Note that components and processes that perform the same operation, action, and function are given the same reference numerals throughout all the drawings, and duplicated explanations may be omitted as appropriate. Each drawing is merely a schematic illustration to allow a sufficient understanding of the technology of the present disclosure. Therefore, the technology of the present disclosure is not limited to only the illustrated examples. Also, in this embodiment, explanations of configurations that are not directly related to the technology of the present disclosure or well-known configurations may be omitted.

[First embodiment]
FIG. 1 is a diagram showing an example of the configuration of a fuel cell system 10 according to a first embodiment.

As shown in FIG. 1, the fuel cell system 10 according to this embodiment is composed of three units: a fuel cell unit 12, a tank unit 13, and a water heater unit 14. The fuel cell unit 12 generates electricity using fuel gas and water, and the tank unit 13 stores a heat transfer medium used in the fuel cell unit 12. The water heater unit 14 is an example of a backup heat source device, and heats the hot water supplied from the fuel cell unit 12 to a desired temperature and supplies it. The fuel cell unit 12, the tank unit 13, and the water heater unit 14 each have a fuel cell unit housing 12A, a tank unit housing 13A, and a water heater unit housing 14A, and each device is arranged inside.

The fuel cell unit housing 12A, the tank unit housing 13A, and the water heater unit housing 14A are each independent, and each unit 12, 13, and 14 is configured separately. Note that in this embodiment, the fuel cell system 10 is shown as being configured as three units, but the fuel cell unit 12 and the tank unit 13 may be integrated and configured as two units with the water heater unit 14.

The fuel cell unit 12 of the fuel cell system 10 includes a fuel cell module 20, which is an example of a fuel cell that generates electricity. The fuel cell module 20 is connected to a gas fitting 22 via a gas supply path 21, and a gas supply pipe 24 is connected to the gas fitting 22.

The gas supply pipe 24 is connected to the gas main pipe, and city gas (raw material gas) containing methane, an example of a hydrocarbon raw material, as its main component, is supplied to the gas supply pipe 24. A desulfurization section 26 is provided in the gas supply path 21, and sulfur and sulfur compounds contained in the city gas are removed in the desulfurization section 26 and supplied to the fuel cell module 20.

The fuel cell module 20 is also connected to a reforming water tank 32 via a reforming water inlet passage 30 having a supply pump 28, and reforming water stored in the reforming water tank 32 is supplied to the fuel cell module 20 by the supply pump 28. This fuel cell module 20 is equipped with a hydrogen generation section (reformer) that generates hydrogen by a reforming reaction between city gas and the reforming water.

Figure 2 is a diagram showing an example of the configuration of the fuel cell module 20 according to the first embodiment.

As shown in FIG. 2, the fuel cell module 20 is mainly composed of a reforming catalyst 202, a burner 204, and a fuel cell stack 206 inside a housing 201.

The reforming catalyst 202 is connected to the gas supply line 21. City gas from which sulfur compounds have been adsorbed and removed in the desulfurization section 26 is supplied to the reforming catalyst 202 through the gas supply line 21. The reforming catalyst 202 steam reforms the supplied city gas using reforming water (condensed water) supplied through the reforming water inlet line 30.

A stack exhaust gas pipe 210 is connected to the burner 204. This burner 204 burns the burner gas (stack exhaust gas) supplied through the stack exhaust gas pipe 210, and heats the reforming catalyst 202. The stack exhaust gas contains unreacted hydrogen gas. Then, in this reforming catalyst 202, fuel gas containing hydrogen gas is generated from the city gas supplied from the desulfurization section 26. This fuel gas is supplied to the fuel electrode 206A of the fuel cell stack 206 through the fuel gas pipe 212.

The fuel cell stack 206 is, for example, a solid oxide fuel cell stack, and has a plurality of stacked fuel cell cells 211 (only one is shown in FIG. 2). Each fuel cell 211 has an electrolyte layer 206C, and a fuel electrode 206A and an air electrode 206B stacked on the front and back surfaces of the electrolyte layer 206C, respectively.

An oxidizing gas (air outside the housing) is supplied to the air electrode 206B (cathode) through an oxidizing gas pipe 214 equipped with an air blower 212. At the air electrode 206B, oxygen in the oxidizing gas reacts with electrons to generate oxygen ions, as shown in the following formula (1). These oxygen ions pass through the electrolyte layer 206C to reach the fuel electrode 206A.

(Air electrode reaction)
1/2O ₂ +2e ^- →O ^2-... (1)

Meanwhile, at the fuel electrode 206A, as shown in the following formulas (2) and (3), oxygen ions that have passed through the electrolyte layer 206C react with hydrogen and carbon monoxide in the fuel gas to generate water (water vapor), carbon dioxide, and electrons. The electrons generated at the fuel electrode 206A reach the air electrode 206B through an external circuit. In this way, the electrons move from the fuel electrode 206A to the air electrode 206B, generating electricity in each fuel cell 211. In addition, each fuel cell 211 generates heat as a result of the above reaction during power generation.

(Anode reaction)
H ₂ +O ^2- →H ₂ O+2e ^-... (2)
CO+O ^2- →CO ₂ +2e ^-... (3)

The upstream side of the stack exhaust gas pipe 210 connected to the fuel cell stack 206 is branched into an anode exhaust gas pipe 208A and an air electrode exhaust gas pipe 208B, which are connected to the anode 206A and the air electrode 206B, respectively. The anode exhaust gas discharged from the anode 206A and the air electrode exhaust gas discharged from the air electrode 206B are discharged through the anode exhaust gas pipe 208A and the air electrode exhaust gas pipe 208B, and are mixed in the stack exhaust gas pipe 210 to form stack exhaust gas. This stack exhaust gas contains unreacted hydrogen gas contained in the anode exhaust gas, and is supplied to the burner 204 as burner gas as described above. In addition, an exhaust path 34 that discharges the burner exhaust gas to the exhaust heat exchanger 36 is connected to this burner 204.

The exhaust heat exchanger 36 is connected to the reforming water tank 32. The combustion exhaust gas from the fuel cell module 20 is cooled in the exhaust heat exchanger 36, and the water vapor in the combustion exhaust gas is condensed. As a result, the combustion exhaust gas is separated into water and gas, and the water is sent to the reforming water tank 32 and reused as reforming water. The gas is exhausted from the exhaust port 15.

Figure 3 is a diagram showing an example of the drainage configuration of the reforming water tank 32 according to the first embodiment.

As shown in FIG. 3, the reforming water tank 32 is provided with a reforming water storage section 32A, a wastewater storage section 32B, and a surplus storage section 32C, which are separated by partitions. The reforming water storage section 32A stores condensed water sent from the exhaust heat exchange section 36 via the discharge path 34 as reforming water. The wastewater storage section 32B stores water that has overflowed from the reforming water storage section 32A, and is connected to a first drainage channel 102 and a drainage pipe 104 that discharge the stored water to the outside. The first drainage channel 102 inside the housing and the drainage pipe 104 outside the housing are connected via a drainage joint 102a. The surplus storage section 32C is connected to a second drainage channel 105 that directly discharges water that has overflowed from the wastewater storage section 32B to the outside. In other words, the first drainage channel 102 and the second drainage channel 105 are provided inside the housing, and the drainage pipe 104 is provided outside the housing.

As shown in FIG. 1, a depressurization channel 41 that guides the water discharged from the pressure relief valve 35 is connected to the drainage reservoir 32B. In this case, the water discharged through the pressure relief valve 35 flows from the pressure relief channel 41 into the drainage reservoir 32B. The pressure relief valve 35 and the pressure relief channel 41 are not essential, and the configuration may be such that the pressure relief valve 35 and the pressure relief channel 41 are not provided.

A first drainage channel 102 having a drainage pump 100 is connected to the drainage storage section 32B, and the first drainage channel 102 is connected to a drainage receiver 120 via a drainage pipe 104 connected to a drainage joint 102a. The drainage that flows into the drainage receiver 120 can be discharged into a sewer or the like.

The reforming water tank 32 is provided with a liquid level sensor 33 that detects the liquid level in the drainage storage section 32B. The drainage pump 100 operates when the liquid level sensor 33 detects that the water in the drainage storage section 32B has reached a predetermined level or more, and sends the water in the drainage storage section 32B through the first drainage channel 102 and the drainage pipe 104 to the drainage receiver 120, which serves as a drainage facility.

The drainage configuration of the reforming water tank 32 according to this embodiment will be specifically described with reference to FIG. 3.

The fuel cell system 10 has a pump discharge method as the main drainage method, and an overflow method as a backup drainage method. In the pump discharge method, the water in the drainage storage section 32B (hereinafter also referred to as "drain water") is guided by the drainage pump 100 to the drainage receiver 120 via the first drainage channel 102 and the drainage piping 104 outside the housing. On the other hand, in the overflow method, the drainage water overflowing from the drainage storage section 32B is stored in the surplus storage section 32C, and is discharged directly to the outside of the housing from the second drainage channel 105 connected to the surplus storage section 32C without going through the drainage piping.

In the pump discharge method, the liquid level sensor 33 detects that a certain amount of drain water has accumulated in the drainage storage section 32B, and the drainage water is drained (intermittently) by the drainage pump 100. If the drainage pipe 104 freezes and becomes clogged, the drainage pump 100 cannot drain the water and a drainage abnormality error is detected. Meanwhile, the excess drainage water is discharged from the excess storage section 32C to the outside of the housing by overflow. The excess storage section 32C that stores the excess drainage water is provided with a second drainage channel 105 that extends to the outside of the housing, but since the second drainage channel 105 is inside the housing, it will not freeze and become clogged.

Returning to FIG. 1, the power from the fuel cell module 20 is converted to AC by the inverter circuit 38 and then supplied to the outside via the supply line 92a connected to the connection terminal 40a.

A heat recovery circuit 42 is connected to the exhaust heat exchange section 36, which circulates the heat transfer medium 50 between the exhaust heat exchange section 36 and the hot water storage tank 48. A heat recovery pump 44 and a radiator 46 are provided in a first flow path 42a, which is one of the flow paths of the heat recovery circuit 42 that connects the exhaust heat exchange section 36 and the hot water storage tank 48. The upstream side of the radiator 46 of the first flow path 42a is connected to the hot water storage tank 48 via joints 42b, 42d and a pipe 42c. Hot water 50 is stored in the hot water storage tank 48.

This first flow path 42a is connected to the bottom of the hot water storage tank 48, and hot water 50 stored in the bottom of the hot water storage tank 48 is sent preferentially to the exhaust heat exchange section 36. The hot water 50 supplied from the hot water storage tank 48 to the first flow path 42a of the heat recovery circuit 42 is cooled by the radiator 46 and then sent to the exhaust heat exchange section 36 by the heat recovery pump 44. The fan motor of the radiator 46 operates as necessary, for example when the hot water 50 being supplied is high temperature.

The hot water 50 sent from the hot water storage tank 48 to the exhaust heat exchanger 36 via the first flow path 42a is returned to the hot water storage tank 48 via the second flow path 42e, which is the other flow path of the heat recovery circuit 42. The second flow path 42e is connected to the top of the hot water storage tank 48 via joints 42f, 42h and piping 42g. The heat of the combustion exhaust gas from the fuel cell module 20 is transferred to the hot water 50 by the exhaust heat exchanger 36, and the hot water 50 heated by this heat is returned to the top of the hot water storage tank 48.

The second flow path 42e is provided with a pressure relief valve 35. The pressure relief valve 35 is formed of a valve body that opens when the pressure in the second flow path 42e reaches or exceeds a predetermined value. The pressure relief valve 35 releases the pressure in the second flow path 42e, preventing the internal pressure of the hot water storage tank 48 and the heat recovery circuit 42 from reaching or exceeding the predetermined internal pressure P0.

An inflow passage 60 having an inflow side branch point 60a is connected to the bottom of the hot water storage tank 48 of the tank unit 13. The inflow passage 60 is connected to an inlet pipe fitting 62. The inlet pipe fitting 62 is connected to a water supply pipe 64, for example, of a water pipe, and clean water is supplied to the inflow passage 60.

A bypass path 74 branches off from the inlet branch point 60a to the fuel cell unit 12. The bypass path 74 is connected to the mixing valve 72 via joints 74a and 74b.

The clean water stored in the hot water tank 48 is sent to the mixing valve 72 in the fuel cell unit 12 via the clean water supply line 400 connected to the top of the hot water tank 48. The clean water supply line 400 is connected to the fuel cell unit 12 via a joint 400a, a pipe 400b, and a joint 400c. The clean water flowing through the clean water supply line 400 is supplied to the water heater unit 14 via the mixing valve 72, the outlet joint 76, and the hot water outlet pipe 78.

The mixing valve 72 is a valve that mixes the clean water from the bypass line 74 with the clean water from the hot water tank 48, and adjusts the mixing ratio of the clean water from the inlet line 60 and the clean water from the hot water tank 48 so that, for example, the outlet temperature becomes a predetermined set temperature.

The downstream side of the mixing valve 72 of the clean water supply line 400 is connected to an outlet fitting 76, which is connected to the water inlet fitting 80 of the water heater unit 14 via a hot water outlet pipe 78.

The fuel cell unit 12 is provided with a control device 110 as a controller. The control device 110 controls the operation (i.e., driving) of the fuel cell system 10. The control device 110 controls various electrical components provided in each of the fuel cell unit 12, the tank unit 13, and the water heater unit 14. A remote control device 51 is also connected to the control device 110. The remote control device 51 accepts operation input from the user and displays various information such as status information and error information of the fuel cell system 10. The control device 110 controls the operation of, for example, each of the pumps 28, 44, 100 and the inverter circuit 38.

Inside the housing of the fuel cell unit 12, a temperature sensor S is provided to measure the air temperature around the fuel cell unit 12. The housing of the fuel cell unit 12 is also provided with a release switch SW to forcibly release the drainage abnormality error if the system stops due to the drainage abnormality error. The release switch SW may be provided in the remote control device 51.

The fuel cell system 10 according to this embodiment generates electricity by reusing condensed water as reforming water and discharging the excess water as drain water.

The water heater unit 14 of this embodiment is a latent heat recovery type heat source machine that further heats the hot water supplied from the fuel cell unit 12 and can then be discharged. A latent heat recovery type heat source machine is a type of heat source machine that improves thermal efficiency by recovering the latent heat in the exhaust gas by converting the water vapor in the exhaust gas from the burner 150 into water (condensed water). As shown in FIG. 1, the water heater unit 14 includes a secondary heat exchanger 154B, a primary heat exchanger 154A, a water inlet passage 152 that supplies hot water from the fuel cell unit 12 to the secondary heat exchanger 154B and the primary heat exchanger 154A, a burner 150 as a heating device that heats the primary heat exchanger 154A, a gas supply pipe 24 that supplies fuel gas to the burner 150, a hot water supply passage 158 that discharges hot water that has passed through the primary heat exchanger 154A, a mixing valve 156 connected to a bypass passage 160 and the hot water supply passage 158 that are connected midway through the piping 152, a hot water supply pipe 86 that discharges hot water from the mixing valve 156, a temperature sensor (not shown) that measures the temperature of the discharged hot water, a control device 164, and the like. The control device 164 controls electrical components such as the mixing valve 156 and a flow rate adjustment valve (not shown) for the fuel gas sent to the burner 150.

Note that in FIG. 1, the fuel cell unit 12 and the water heater unit 14 are shown close to each other, but in an actual home, the fuel cell unit 12 and the water heater unit 14 may be separated by some distance.

A gas supply pipe 24 is connected to the gas fitting 82 of the water heater unit 14, and city gas is supplied from the gas supply pipe 24 to the burner 150 of the water heater unit 14. A hot water supply pipe 86 is connected to the hot water fitting 84 of the water heater unit 14, and the hot water supply pipe 86 is routed to a hot water supply location where hot water is used. A drain pipe 88 connected to the water heater unit 14 is connected to a drain receiver 120. Water generated by condensation in the water heater unit 14 flows into the drain pipe 88, and the condensed water is led to the drain receiver 120.

The water inlet fitting 80 of the water heater unit 14 is connected to a water inlet passage 152, which is connected to a secondary heat exchanger 154B. The secondary heat exchanger 154B is connected to a primary heat exchanger 154A, which is connected to the water supply fitting 84 via a hot water supply passage 158 having a mixing valve 156, which is connected to the water inlet side branch point 152a of the water inlet passage 152 via a bypass passage 160. The mixing valve 156 is a valve that mixes the hot water from the water inlet passage 152 and the hot water from the primary heat exchanger 154A, and adjusts the mixing ratio of the hot water from the water inlet passage 152 and the hot water from the primary heat exchanger 154A.

The control device 164 of this water heater unit 14 includes a microcomputer and the like, and the microcomputer adjusts the amount of combustion in the burner 150 to control the amount of heating of the clean water in the primary heat exchanger 154A, and also controls the opening degree of the mixing valve 156. As a result, the microcomputer of the control device 164 controls the hot water temperature from the hot water supply pipe 86 to the set temperature set by the remote control device 51.

Figure 4 is a block diagram showing an example of the electrical configuration of the control device 110 according to the first embodiment.

As shown in FIG. 4, the control device 110 according to this embodiment includes a CPU (Central Processing Unit) 111, a ROM (Read Only Memory) 112, a RAM (Random Access Memory) 113, an input/output interface (I/O) 114, a storage unit 115, a communication unit 116, and an external interface (hereinafter referred to as "external I/F") 117.

The CPU 111, ROM 112, RAM 113, and I/O 114 are each connected via a bus. The I/O 114 is connected to various functional units including a memory unit 115, a communication unit 116, and an external I/F 117. These functional units are capable of communicating with the CPU 111 via the I/O 114.

For example, a hard disk drive (HDD), a solid state drive (SSD), a flash memory, etc., is used as the storage unit 115. A control program 115A for controlling the operation of the fuel cell system 10 is stored in the storage unit 115. This control program 115A may be stored in the ROM 112.

The control program 115A may be pre-installed in the control device 110, for example. The control program 115A may be realized by storing it in a non-volatile storage medium or distributing it via a network and installing it appropriately in the control device 110. Examples of non-volatile storage media include a CD-ROM (Compact Disc Read Only Memory), an optical magnetic disk, a HDD, a DVD-ROM (Digital Versatile Disc Read Only Memory), a flash memory, a memory card, etc.

The communication unit 116 is connected to a network such as the Internet, a LAN (Local Area Network), or a WAN (Wide Area Network), and is capable of communicating via the network with a web server that can provide various types of information such as weather information and calendar information.

To the external I/F 117, for example, a release switch SW, a temperature sensor S, a remote control device 51, a liquid level sensor 33, and a drainage pump 100 are connected. These release switch SW, temperature sensor S, remote control device 51, liquid level sensor 33, and drainage pump 100 are connected to the CPU 111 via the external I/F 117 so as to be able to communicate with each other.

However, as mentioned above, depending on the system, the system may determine that an abnormality exists due to the inability to drain water caused by frozen drainage pipes 104, and the system may shut down due to a drainage abnormality error. Normally, for safety reasons, this drainage abnormality error is designed in such a way that the user cannot reset it, resulting in a loss of power generation opportunities and requiring the dispatch of maintenance personnel.

Therefore, the CPU 111 of the control device 110 according to this embodiment functions as each unit shown in FIG. 5 by writing the control program 115A stored in the memory unit 115 to the RAM 113 and executing it.

Figure 5 is a block diagram showing an example of the functional configuration of the control device 110 according to the first embodiment.

As shown in FIG. 5, the CPU 111 of the control device 110 according to this embodiment functions as an error detection unit 111A, an acquisition unit 111B, a low temperature determination unit 111C, and a drainage control unit 111D. The drainage control unit 111D is an example of a control unit.

The error detection unit 111A detects a drainage abnormality error that indicates that there is an abnormality in the drainage from the drainage storage unit 32B. Conditions for determining that a drainage abnormality error has occurred include, for example, that the water level in the drainage storage unit 32B does not drop, that the drainage flow rate drops below a set value, etc.

When the error detection unit 111A detects a drainage abnormality error, the acquisition unit 111B acquires the air temperature measured by the temperature sensor S. Note that the air temperature here refers to the air temperature around the fuel cell unit 12, as described above.

The acquisition unit 111B may also acquire weather information for the area in which the system is installed when a drainage abnormality error is detected. The weather information is acquired, for example, via the Internet from a web server that provides weather information. The weather information includes information on the local weather (sunny, cloudy, rainy, snowy, etc.), temperature (maximum temperature/minimum temperature, etc.), etc.

The acquisition unit 111B may also acquire calendar information indicating the time when a drainage abnormality error is detected. The calendar information may be acquired, for example, by using a calendar function of the control device 110, or may be acquired via the Internet from a web server that provides calendar information. The calendar information includes information such as the date when the drainage abnormality error was detected.

The low temperature determination unit 111C determines whether or not a condition indicating that the temperature of the external environment is relatively low (hereinafter, simply referred to as the "low temperature condition") is satisfied. Specifically, the low temperature condition includes, for example, the air temperature measured by the temperature sensor S being equal to or lower than a threshold value. When using the temperature measured by the temperature sensor S, the threshold value is set to an appropriate value, for example, in the range of 4°C to 7°C. In addition, a temperature history of the air temperature around the fuel cell unit 12 may be stored. The temperature history is a history of measured temperatures obtained by measuring the air temperature around the fuel cell unit 12. For example, each measured temperature in the temperature history may be associated with whether or not the water in the first drainage channel 102 and the drainage pipe 104 has frozen, and the measured temperature when the water actually freezes may be used as the threshold value. Note that, if there are multiple measured temperatures when the water actually freezes, the maximum temperature among these multiple measured temperatures may be used as the threshold value.

When weather information is used, the low temperature condition includes, for example, the temperature obtained from the weather information being equal to or lower than a threshold value. In this case, an appropriate threshold value can be set based on information such as the local weather (sunny, cloudy, rainy, snowy, etc.) and temperature (maximum temperature/minimum temperature, etc.).

In addition, when calendar information is used, the low temperature condition includes the period obtained from the calendar information being a relatively low temperature period. In this case, for example, if the period when the drainage abnormality error was detected is between December and March, it may be determined that the environment is a low temperature environment.

When the drainage control unit 111D detects a drainage abnormality error and the low temperature condition is met, it disables the stop of the operation of the fuel cell system 10 and controls the system to continue generating power. When the drainage control unit 111D determines that the environment is low temperature, it controls the remote control device 51, which is an example of a user interface, to display a drainage abnormality error and to display a message indicating that power generation will continue without stopping the system due to a suspected freeze blockage. In other words, even if the drainage pipe 104 is frozen and blocked, power generation will continue while the excess drain water is discharged outside the housing using an overflow method. This makes it possible to avoid losing power generation opportunities and to avoid the need to call in maintenance personnel.

Next, the operation of the control device 110 according to the first embodiment will be described with reference to FIG.

Figure 6 is a flowchart showing an example of the processing flow of control program 115A according to the first embodiment.

When a drainage control command is issued to the fuel cell system 10, the CPU 111 starts the control program 115A stored in the memory unit 115, and the following steps are executed.

In step S101 in FIG. 6, the CPU 111 determines whether or not a drainage abnormality error has been detected. If it is determined that a drainage abnormality error has been detected (positive determination), the process proceeds to step S102, and if it is determined that a drainage abnormality error has not been detected (negative determination), the process waits in step S101. As described above, conditions for determining that a drainage abnormality error has occurred include, for example, the water level in the drainage storage section 32B not dropping, the drainage flow rate dropping below a set value, etc.

In step S102, the CPU 111 determines whether or not it is a low temperature environment, that is, whether or not the low temperature condition is satisfied. If it is determined that the low temperature condition is satisfied (if a positive determination), the process proceeds to step S103, and if it is determined that the low temperature condition is not satisfied (if a negative determination), the process proceeds to step S107. As described above, the low temperature condition includes at least one of, for example, the temperature measured by the temperature sensor S being below a threshold, the temperature obtained from the weather information being below a threshold, and the period obtained from the calendar information being a relatively low temperature period.

In step S103, the CPU 111 disables the stop of operation of the fuel cell system 10 due to the suspicion of freeze blockage. In other words, power generation continues while the excess drain water is discharged to the outside of the housing using the overflow method.

In step S104, the CPU 111, for example, controls the remote control device 51 to display a drainage abnormality error and to display a message indicating that power generation will continue without shutting down the system due to suspected freeze blockage.

In step S105, the CPU 111 determines whether or not the stop switch has been pressed. If it is determined that the stop switch has not been pressed (in the case of a negative determination), the process proceeds to step S106, and if it is determined that the stop switch has been pressed (in the case of a positive determination), the process proceeds to step S107. The stop switch is a switch for forcibly stopping the system, and is provided, for example, on the remote control device 51.

In step S106, the CPU 111 determines whether the end timing has arrived. If it is determined that the end timing has not arrived (if the determination is negative), the process returns to step S101 and is repeated. If it is determined that the end timing has arrived (if the determination is positive), the process by the control program 115A ends.

On the other hand, in step S107, the CPU 111 stops operation of the fuel cell system 10 because it suspects something other than freeze blockage.

In step S108, the CPU 111, for example, controls the remote control device 51 to display a drainage abnormality error and to display a message indicating that a request for dispatching maintenance personnel is required, and ends the series of processes performed by the control program 115A.

In this way, according to this embodiment, when a drainage abnormality error occurs in a low-temperature environment, it is possible to avoid the need to dispatch maintenance personnel without losing the opportunity to generate electricity.

Second Embodiment
In the above-described first embodiment, a configuration in which a pump sending system is adopted as a main drainage system has been described. In the present embodiment, a configuration in which a gravity flow system is adopted as a main drainage system will be described.

Figures 7 and 8 are diagrams showing an example of the drainage configuration of the reforming water tank 32 according to the second embodiment. Note that in this embodiment, the drainage pump 100 is not required.

The fuel cell system 10 has a gravity flow method as the main drainage method and an overflow method as a backup drainage method. In the gravity flow method, the drain water in the drainage storage section 32B is guided by gravity down through the first drainage channel 102 and the drainage piping 104 to the drainage receiver 120, and in the overflow method, the drain water that overflows from the drainage storage section 32B is stored in the surplus storage section 32C and is discharged directly to the outside of the housing from the second drainage channel 105 connected to the surplus storage section 32C without going through the drainage piping.

Under normal circumstances, drain water is drained by gravity as shown in Figure 7. In this case, the water level does not rise to the liquid level sensor 33. On the other hand, under abnormal circumstances (when the drain pipe is blocked), the drain water in the drainage storage section 32B cannot be drained as shown in Figure 8, the water level rises to the position of the liquid level sensor 33, and a drainage abnormality error is detected.

Referring to FIG. 5 above, the drainage control unit 111D according to this embodiment, like the first embodiment, detects a drainage abnormality error and, if the low temperature condition is satisfied, disables the stop of the operation of the fuel cell system 10 and controls the system to continue generating power. However, conditions for determining that a drainage abnormality error has occurred include, for example, an increase in the water level in the drainage storage unit 32B. The low temperature condition is determined, for example, by at least one of the temperature measured by the temperature sensor S, weather information, and calendar information.

According to this embodiment, even if the gravity flow method is used as the main drainage method, if a drainage abnormality error occurs in a low-temperature environment, it is possible to avoid the need to dispatch maintenance personnel without losing power generation opportunities.

Although the above embodiments have been described using a fuel cell system and a control device as examples, the embodiments may also be in the form of a program for causing a computer to execute the functions of each unit of the control device. The embodiments may also be in the form of a computer-readable storage medium that stores the program.

The configurations of the fuel cell system and control device described in each of the above embodiments are merely examples, and may be modified according to circumstances without departing from the spirit of the invention.

The processing flow of the program described in each of the above embodiments is also an example, and unnecessary steps may be deleted, new steps may be added, or the processing order may be rearranged, without departing from the spirit of the invention.

In addition, in each of the above embodiments, a case has been described in which the processing according to the embodiment is realized by a software configuration using a computer by executing a program, but this is not limited to this. The embodiment may be realized, for example, by a hardware configuration or a combination of a hardware configuration and a software configuration.

REFERENCE SIGNS LIST 10 Fuel cell system 12 Fuel cell unit 13 Tank unit 14 Water heater unit 20 Fuel cell module 32 Reformed water tank 32A Reformed water storage section 32B Drainage storage section 32C Surplus water storage section 33 Liquid level sensor 34 Drain path 51 Remote control device 100 Drainage pump 102 First drainage path 104 Drainage pipe 105 Second drainage path 110 Control device 111 CPU
111A Error detection unit 111B Acquisition unit 111C Low temperature determination unit 111D Drainage control unit 112 ROM
113 RAM
114 I/O
115 Storage unit 115A Control program 116 Communication unit 117 External I/F
120 Drainage receiver

Claims (9)

a fuel cell module for generating electricity;
a reforming water tank including a reforming water storage section that stores water obtained from exhaust gas discharged from the fuel cell module as reforming water to be introduced into the fuel cell module;
a drainage reservoir section that is provided in the reforming water tank and that stores water that overflows from the reforming water reservoir section and is connected to a first drainage channel and a drainage pipe that discharge the stored water to the outside;
a surplus water storage section provided in the reforming water tank and connected to a second drainage channel for directly discharging water overflowing from the drainage storage section to the outside;
A control device including a control unit that, when detecting a drainage abnormality error and satisfying a condition indicating that the temperature of the external environment is relatively low, disables the shutdown of the system and controls the system to continue generating power;
A fuel cell system comprising: a housing for housing the fuel cell module, the reforming water tank, and the control device;
The first drainage channel and the second drainage channel are provided in the housing,
The fuel cell system according to claim 1 , wherein the drainage pipe is provided outside the housing and is connected to the drainage reservoir via the first drainage channel. the control device further includes an acquisition unit that acquires an air temperature measured around a fuel cell unit in which the fuel cell module is provided when the control device detects an error of the drainage abnormality;
3. The fuel cell system according to claim 1, wherein the condition indicating that the temperature of the external environment is relatively low includes the air temperature being equal to or lower than a threshold value. The control device further includes an acquisition unit that acquires weather information of an area in which the control device is installed when the control device detects an error of the drainage abnormality,
3. The fuel cell system according to claim 1, wherein the condition indicating that the temperature of the external environment is relatively low includes an air temperature obtained from the weather information being equal to or lower than a threshold value. The control device further includes an acquisition unit that acquires calendar information indicating a time when the drainage abnormality error is detected,
3. The fuel cell system according to claim 1, wherein the condition indicating that the temperature of the external environment is relatively low includes a period obtained from the calendar information being a relatively low-temperature period. Further comprising a drainage pump provided in the first drainage channel,
6. The fuel cell system according to claim 1, wherein a drainage system of the drainage reservoir is a pump delivery system in which drainage is performed by using the drainage pump. 6. The fuel cell system according to claim 1, wherein a drainage method of the wastewater storage section is a gravity flow method in which drainage is performed under natural flow. a fuel cell module for generating electricity;
a reforming water tank including a reforming water storage section that stores water obtained from exhaust gas discharged from the fuel cell module as reforming water to be introduced into the fuel cell module;
a drainage reservoir section that is provided in the reforming water tank and that stores water that overflows from the reforming water reservoir section and is connected to a first drainage channel and a drainage pipe that discharge the stored water to the outside;
a surplus water storage section provided in the reforming water tank and connected to a second drainage channel that directly discharges water overflowing from the drainage storage section to the outside,
A control device including a control unit that, when a drainage abnormality error is detected and a condition indicating that the temperature of the external environment is relatively low is met, disables the shutdown of the system and controls the system to continue generating power. A control program for causing a computer to function as a control unit included in a control device for controlling the fuel cell system according to any one of claims 1 to 7.