JP5631037B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system.

  As a conventional fuel cell system, one that effectively uses the exhaust heat of a fuel cell or a reformer is known (see, for example, Patent Document 1). In the system described in Patent Document 1, a fuel cell main body, a fuel processing system for reforming fuel, a hot water storage tank for recovering exhaust heat, and a radiator for releasing exhaust heat that cannot be recovered indoors are used to prevent freezing. Placed indoors. And the system of patent document 1 performs the operation | movement which supplies warm air indoors with a heat radiator, when the exhaust heat exceeding the heat storage amount of a hot water storage tank arises, and temperature is low. On the other hand, when exhaust heat exceeding the heat storage amount of the hot water tank is generated and the temperature is high, the operation of the fuel cell system is stopped without operating the radiator.

JP 2009-21047 A

  By the way, depending on the type of fuel cell, the loss and operating load accompanying the restart of the fuel cell system are large. Therefore, in a fuel cell system having such a fuel cell, it is preferable to operate continuously from the viewpoint of energy efficiency. . However, in the fuel cell system described in Patent Document 1, since the operation of the fuel cell system is stopped in order to prevent generation of unusable waste heat, the energy efficiency of the entire system may be lowered depending on the type of fuel cell. There is.

  Accordingly, the present invention has been made to solve such a technical problem, and provides a fuel cell system capable of effectively using exhaust heat according to the temperature in a state where the fuel cell is continuously operated. The purpose is to do.

In order to solve the above-described problems, a fuel cell system according to the present invention includes a hut arranged outdoors, a fuel cell main body that outputs electric power, and heat that transfers exhaust heat generated from the fuel cell main body to a heat recovery system. and exchanger, a heat accumulator which stores heat of the heat recovered by arranged the heat recovery system in a small indoor, a radiator that is located in a small indoor, more radiated to blowing recovered heat by the heat recovery system, disposed within hut, constructed and a switching means which can switch out cabin within or shed the blast destination of the radiator.

  According to the fuel cell system according to the present invention, since the heat accumulator and the radiator are arranged indoors, freezing can be suppressed. In addition, since it is possible to switch the air blowing destination of the radiator to indoors or outdoors, freezing can be further suppressed by setting the air blowing destination indoors when the temperature is low, for example, and when the air temperature is high, for example, By making the outdoor, the fuel cell system can be continuously operated without increasing the indoor temperature. Therefore, the exhaust heat according to the temperature can be effectively used in a state where the fuel cell is continuously operated.

Here, when the heat storage amount measuring device for measuring the heat storage amount of the heat storage device, the air temperature measurement device for measuring the air temperature, the heat storage device exceeds the heat storage amount capable of storing heat, and the air temperature is equal to or lower than a predetermined temperature. In this case, it is preferable to include a control unit that operates the switching unit so that the air blowing destination of the radiator is directed to the small indoor space. By comprising in this way, since a control part operates a switching means based on heat storage amount and air temperature, the effective utilization of the waste heat according to air temperature can be performed with an apparatus, for example. Further, when the temperature is low, it is possible to supply hot air to the small indoor space using surplus heat that cannot be stored by the heat accumulator, and thus it is possible to prevent freezing using surplus heat.

The control unit may operate the switching means so blowing amount to as the air temperature is low the radiator in the cabin is increased. By comprising in this way, the freezing suppression effect can be heightened further.

  The fuel cell body may be a solid oxide fuel cell.

  According to the present invention, it is possible to effectively use exhaust heat according to the temperature in a state where the fuel cell is continuously operated.

1 is a schematic configuration diagram of an embodiment of a fuel cell system according to the present invention. 2 is a flowchart showing a switching operation of the fuel cell system of FIG. 1.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same or an equivalent part, and the overlapping description is abbreviate | omitted.

  The fuel cell system according to the present embodiment is suitably employed as a household fuel cell system, for example. FIG. 1 is a schematic configuration diagram of an embodiment of a fuel cell system according to the present invention. As shown in FIG. 1, the fuel cell system 1 includes a fuel cell main body 2 and a hot water storage unit 3.

  The fuel cell body 2 is a DC power source having a stack 20 in which unit cells are connected in series, and supplies power to, for example, a household load. The fuel cell body 2 is disposed outdoors, for example. As the fuel cell body 2, for example, a solid oxide fuel cell is used. The fuel cell main body 2 includes a heat exchanger 21. The heat exchanger 21 recovers the heat generated in the fuel cell main body 2 and transfers the heat to the water in the heat recovery system 4 that circulates water between the heat exchanger 21 and the hot water storage unit 3. The heat recovery system 4 includes pipes H1 to H3 and a water pump (not shown), and has a circulation path.

  The hot water storage unit 3 is disposed in a highly airtight box-shaped shed 9 to prevent freezing due to a decrease in temperature. The hot water storage unit 3 includes a hot water storage tank (heat accumulator) 31, a three-way valve 10, a radiator 6 and a blower fan 5. The radiator 6 and the blower fan 5 constitute a radiator.

  The hot water storage tank 31 is a tank that stores the water that is heat-transferred in the heat exchanger 21. The three-way valve 10 connects a pipe H <b> 3 of the heat recovery system 4 connected to the heat exchanger 21 and a pipe H <b> 1 connected to the hot water storage tank 31. The hot water tank 31 is connected to the pipe H1 in the upper part, and is configured such that the water transferred by the heat exchanger 21 can flow in through the pipe H1. In addition, the hot water storage tank 31 is connected to the pipe H <b> 2 at the lower part, so that water stored in the lower part of the hot water storage tank 31 flows out and can flow into the heat exchanger 21 via the radiator 6. In addition, the three-way valve 10 connects the pipe H3 of the heat recovery system 4 connected to the heat exchanger 21 and the pipe H2, so that the heat transferred water does not flow into the hot water tank 31 and goes to the radiator 6. A circulation path that directly flows in and reflows into the heat exchanger 21 is configured.

  The radiator 6 is an air-cooling type and includes heat radiation fins. The blower fan 5 sends wind to the radiator 6 and transmits the heat of the circulating water to the air to produce warm air, which is output to the exhaust duct D0. The exhaust duct D0 branches into an exhaust duct D1 that exhausts to the outside and an exhaust duct D2 that exhausts to the room. The hot water storage unit 3 is connected to the outside through the exhaust duct D1, and is connected to the room through the exhaust duct D2.

  A switching valve (switching means) 7 is disposed at the branch point of the exhaust duct D0. The switching valve 7 has a function of switching the connection between the exhaust duct D0 and the exhaust duct D1, and the connection between the exhaust duct D1 and the exhaust duct D2. That is, the switching valve 7 has a function of switching the air blowing destination of the blower fan 5 to the room or outdoors. As the switching valve 7, a three-way valve, a plug valve, a switching valve, a solenoid valve and a joint, or a passage partitioning by a shutter or a plate member is used.

  Further, the hot water storage unit 3 includes a water temperature meter (heat storage amount measuring device) 30 capable of measuring the temperature of the water stored in the hot water storage tank 31. The hut 9 is provided with a thermometer (air temperature measuring device) 32 capable of measuring the indoor temperature. As the water temperature meter 30 and the air temperature meter 32, a thermocouple, a thermistor, or the like is used.

  The operation of the components of the fuel cell system 1 described above is controlled by a system control device (control unit) 8 that is an electrical component. The system controller 8 is an electronically controlled device, and includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, and the like. The system control device 8 is disposed, for example, in the cabin 9, and is connected to the water temperature gauge 30, the temperature gauge 32, the blower fan 5, and the switching valve 7. The system control device 8 is configured to operate the blower fan 5 and the switching valve 7 based on information output from the water temperature gauge 30 and the temperature gauge 32.

  The fuel cell system 1 supplies the electric power generated by the fuel cell main body 2 to the home, and stores water heated by the heat generated by the power generation in the hot water storage tank 31 so that it can be used at home. Further, when heat that cannot be stored in the hot water storage tank 31 is generated from the fuel cell main body 2, the blower fan 5 is operated to release the heat indoors or outdoors. Below, operation | movement of the fuel cell system 1 is demonstrated in detail using FIG. FIG. 2 is a flowchart showing the operation of the fuel cell system 1. The control process shown in FIG. 2 is repeatedly executed at a predetermined interval from the timing when the power of the fuel cell system 1 is turned on, for example.

  As shown in FIG. 2, the fuel cell system 1 acquires the amount of heat storage (step S10). In step S <b> 10, the system control device 8 acquires a heat storage amount based on the temperature of the water thermometer 30. Alternatively, the system control device 8 may acquire the amount of hot water stored in the hot water storage tank 31 using a sensor (not shown) and acquire the amount of stored heat based on the temperature of the water temperature gauge 30. When the process of step S10 ends, the process proceeds to a heat storage determination process (step S12).

  In the process of step S12, the system control device 8 determines whether or not the hot water storage tank 31 can store heat. The system control device 8 determines whether or not the hot water storage tank 31 can store heat based on the heat storage amount acquired in the process of step S10. For example, the system control device 8 determines that heat storage is possible when the water temperature obtained in the process of step S10 is a predetermined value (for example, 70 ° C.) or less. On the other hand, if the water temperature obtained in the process of step S10 exceeds a predetermined value (for example, 70 ° C.) and the amount of hot water stored in the hot water storage tank 31 is a limit value, the system control device 8 judge. When it is determined in step S12 that heat storage is possible, it is more efficient to store heat than to release exhaust heat, and thus the control process shown in FIG. 2 is terminated. On the other hand, if it is determined in step S12 that heat storage is not possible, the process proceeds to temperature determination processing (step S14).

  In the process of step S14, the system control device 8 determines whether or not the temperature is below a predetermined value. The system control device 8 compares the temperature acquired by the thermometer 32 with a predetermined value (for example, 10 ° C.) and determines whether or not the temperature is equal to or lower than the predetermined value. If it is determined in step S14 that the temperature is equal to or lower than the predetermined value, the process proceeds to a switching process (step S16).

  In the process of step S <b> 16, the system control device 8 operates the switching valve 7 to switch the air blow destination of the hot air from the blower fan 5 to the room. That is, the switching valve 7 is operated to close the flow paths of the ducts D0 and D1, and open the flow paths of the ducts D0 and D2. When the process of step S16 ends, the process proceeds to the blowing process (step S20).

  In the process of step S20, the system control device 8 operates the blower fan 5. Thereby, the warm air is blown into the room through the ducts D0 and D2. When the process of step S20 ends, the control process shown in FIG. 2 ends.

  On the other hand, if it is determined in step S14 that the temperature is not lower than the predetermined value, the process proceeds to switching processing (step S18). In the process of step S <b> 18, the system control device 8 operates the switching valve 7 to switch the hot air blowing destination by the blower fan 5 to the outdoors. That is, the switching valve 7 is actuated to open the ducts D0 and D1, and close the ducts D0 and D2. When the process of step S18 ends, the process proceeds to the blowing process (step S20). In the process of step S20, the system control device 8 operates the blower fan 5. Thereby, warm air is ventilated outside through the ducts D0 and D1. When the process of step S20 ends, the control process shown in FIG. 2 ends.

  The control process shown in FIG. By executing the control process shown in FIG. 2, when heat that cannot be stored in the hot water storage tank 31 is generated from the fuel cell main body 2, if the temperature is below a predetermined value, hot air is supplied indoors, When the temperature is not below a predetermined value, warm air is supplied outdoors. For this reason, for example, when there is a possibility of freezing due to a drop in temperature in winter or in a cold region, it is possible to prevent freezing by sending heat to the hut 9 without being able to store heat. Even when the temperature rises at this time, it is possible to release heat to the outside of the hut 9 without being able to store heat. As described above, the exhaust heat can be appropriately used when the temperature is lowered, and the temperature in the cabin 9 is increased more than necessary even when the fuel cell system 1 is continuously operated when the temperature rises. It can be avoided. This is particularly effective when a solid oxide fuel cell that is difficult to repeat starting and stopping of operation is employed in the fuel cell main body 2. Further, by adopting a solid oxide fuel cell for the fuel cell main body 2, it is not necessary to arrange the entire fuel cell system 1 in the hut 9 as a countermeasure against freezing, and the fuel cell main body 2 is arranged outdoors. Can do. As a result, the building space of the hut 9 can be reduced, so that it is possible to arrange a fuel cell system (a cold region specification fuel cell system) in which a countermeasure against freezing is taken even in a small site. Further, since the fuel cell main body 2 is not arranged in the hut 9, it is possible to avoid discharging gas or the like accompanying power generation into the hut 9, so that both freezing prevention and safety can be achieved. it can.

  As mentioned above, according to the fuel cell system 1 which concerns on this embodiment, since the hot water storage tank 31, the radiator 6, and the ventilation fan 5 are arrange | positioned in the hut 9, freezing can be suppressed. Moreover, since it is possible to switch the ventilation destination of the ventilation fan 5 indoors or outdoors, freezing can be further suppressed by setting the ventilation destination indoors when the temperature is low, and when the temperature is high, the ventilation destination is changed. The outdoor operation of the fuel cell system 1 can be performed without increasing the temperature in the room by using the outdoor unit. Therefore, the exhaust heat according to the temperature can be effectively used in a state where the fuel cell is continuously operated.

  Furthermore, according to the fuel cell system 1 according to the present embodiment, since the system control device 8 operates the switching valve 7 based on the heat storage amount and the air temperature, when the temperature is low, surplus heat that cannot be stored by the regenerator is used. Therefore, it is possible to prevent freezing by using surplus heat.

  The preferred embodiment of the present invention has been specifically described above. However, the above embodiment shows an example of the fuel cell system according to the present invention, and the fuel cell system according to the present invention relates to the above embodiment. It is not limited to the fuel cell system 1.

  For example, in the above-described embodiment, the heat exchanger 21 transmits the exhaust heat generated from the fuel cell main body 2 to the circulating water of the heat recovery system 4. For example, the surplus power of the fuel cell main body 2 is transferred to the surplus heater. For example, the heat exchanger 21 may recover the heat generated by the surplus heater as exhaust heat generated from the fuel cell main body 2 and transmit it to the circulating water of the heat recovery system 4.

  Moreover, in the said embodiment, although the system control apparatus 8 operated the switching valve 7 and demonstrated the example which switches the ventilation destination of the ventilation fan 5 to indoor or the outdoors, for example, the room | chamber interior of the ventilation fan 5 is so low that temperature is low. The switching valve 7 may be operated so that the amount of air flow increases. That is, the system control device 8 stores, for example, a table indicating the dependence between the opening degree of the valve and the air temperature in a storage area such as a ROM, and the lower the air temperature, the more the opening degree of the valve of the flow path into the room. While increasing, you may operate | move so that the opening degree of the valve | bulb of the flow path to the outdoor may be made small. By operating in this way, the effect of suppressing freezing can be further enhanced.

  Moreover, although the system control apparatus 8 demonstrated the example which operates the switching valve 7 and switches the ventilation destination of the ventilation fan 5 to indoor or outdoor in the said embodiment, you may operate the switching valve 7 manually. For example, by manually changing the flow path every season, it is possible to prevent freezing in winter and to continuously operate the fuel cell system 1 in summer. At this time, the switching valve 7 may be configured so that the opening degree can be manually adjusted. Moreover, when adjusting manually, the system control apparatus 8, the water temperature meter 30, and the temperature meter 32 do not need to be provided.

  Furthermore, although the case where the fuel cell main body 2 is a solid oxide fuel cell has been described in the above embodiment, the present invention is not limited to this, and may be, for example, a solid polymer fuel cell.

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 2 ... Fuel cell main body, 3 ... Hot water storage unit, 4 ... Heat recovery system, 5 ... Blower fan (radiator), 6 ... Radiator (radiator), 7 ... Switching valve (switching means), 8 ... System controller (control unit), 9 ... Hut, 10 ... Three-way valve, 20 ... Stack, 21 ... Heat exchanger, 30 ... Water thermometer (heat storage amount measuring device), 31 ... Hot water storage tank (heat storage device), 32 ... Thermometer (temperature measuring instrument).

Claims (4)

A hut located outdoors,
A fuel cell body that outputs power;
A heat exchanger for transferring waste heat generated from the fuel cell body to a heat recovery system;
A heat accumulator which stores heat of the recovered heat by the heat recovery system is placed in a small indoor,
A radiator disposed in the small indoor, more radiated to blowing recovered heat by the heat recovery system,
Disposed within hut, a switching means capable of switching the radiator blower destination outside cabin within or shed,
A fuel cell system comprising: A heat storage amount measuring device for measuring the heat storage amount of the heat storage device; and
A temperature measuring instrument for measuring the temperature;
If the heat accumulator exceeds a thermal energy storage amount thermal storage, and when the air temperature is below the predetermined temperature, a control unit for the radiator blower destination operating said switching means to direct the cabin ,
The fuel cell system according to claim 1, comprising: 3. The fuel cell system according to claim 2, wherein the control unit operates the switching unit so that the amount of air blown into the small indoor space of the radiator is increased as the temperature is lower.   The fuel cell system according to any one of claims 1 to 3, wherein the fuel cell main body is a solid oxide fuel cell.

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