JP2012119332A - Fuel battery system, and method for operating fuel battery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery system which allows an efficient recovery of heat generated by a fuel battery.SOLUTION: The fuel battery system includes: a fuel battery 1 which generates electric power when being supplied with fuel and oxidant; a cooling pipeline 4 which is provided to run through the inside of the fuel battery 1, and through which cooling water for carrying off heat that the fuel battery 1 generates is circulated inside the battery; a cooling-water pump 5 operable to circulate the cooling water through the cooling pipeline 4; a city-water pipeline 8 through which city water is forced to flow; a city water pump 9 for forcing the city water in the city-water pipeline 8 to flow; a heat exchanger 6 operable to perform thermal exchange between the cooling water and city water; and a PID controller. Also, after the stop of power generation by the fuel battery 1, the PID controller continues operating the cooling-water pump 5 and the city water pump 9.

Description

  The present invention relates to a fuel cell system that generates power using a fuel cell.

  A conventional fuel cell system will be described below.

  As shown in FIG. 3, the conventional fuel cell system includes a fuel cell 1 that generates power using fuel gas and an oxidant, and a fuel rich in hydrogen by reforming by adding water to a power generation material such as natural gas. A fuel generator 2 that generates gas, a blower 3 that supplies air as an oxidant to the fuel cell 1, and cooling water to the fuel cell 1 as a first heat medium that extracts heat generated by the fuel cell 1 to the outside. Cooling pipe 4 to be circulated, cooling water pump 5 located in the cooling pipe 4 for conveying the cooling water, and heat exchange for transferring the heat of the cooling water as the first heat medium to the city water as the second heat medium It comprises a vessel 6, a hot water tank 7 for storing city water, a city water pipe 8 for connecting the heat exchanger 6 and the hot water tank 7, and a city water pump 9 for conveying city water.

  The fuel cell 1 generates electric power and heat from the hydrogen-rich fuel gas generated by the fuel generator 2 and the air supplied by the blower 3. Since the fuel generator 2 generates water-rich fuel gas by adding water to a power generation raw material such as natural gas, the fuel generator 2 is maintained at a high temperature (about 700 ° C.) by a burner (not shown) that burns natural gas or the like. ing.

  Heat generated in the fuel cell 1 is conveyed to the outside by cooling water flowing through the cooling pipe 4. The coolant flow rate is such that the coolant temperature Tf detected by the fuel cell temperature detector 10 installed where the coolant flows out of the fuel cell 1 coincides with the target temperature Tr1 (about 70 ° C.). Adjust the conveyance capacity of 5. Here, since the temperature of the fuel cell 1 is considered to be substantially equal to the temperature flowing out of the fuel cell 1, the temperature detected by the fuel cell temperature detector 10 is regarded as the temperature of the fuel cell 1.

  The heat obtained by the cooling water is transmitted to the city water flowing through the city water pipe 8 through the heat exchanger 6. The city water flow rate is such that the city water temperature Tw detected by the city water temperature detector 11 installed where the city water flows out of the heat exchanger 6 coincides with the target temperature Tr2 (about 60 ° C.). The conveyance capacity of the pump 9 is adjusted.

  In such a fuel cell system, when the power generation of the fuel cell 1 is terminated, the supply of the power generation raw material to the fuel generator 2 is stopped, and at the same time, the fuel generator 2 and the raw material gas of the fuel cell 1 are stopped. In general, an inert gas such as nitrogen is sent to the fuel gas flow path and the combustible gas is discarded from the fuel cell system. In addition, since the fuel cell 1 does not generate heat at the same time as power generation is stopped, the cooling water pump 5 and the city water pump 9 also stop the conveying operation, and the circulation of the cooling water and city water also stops.

  In the fuel cell system as in the conventional example described above, after the power generation is completed, the inert gas such as nitrogen that has passed through the fuel gas distribution path from the fuel generator 2 at about 700 ° C. passes through the fuel cell 1. The fuel cell 1 is discharged to the outside.

  However, at this time, the fuel gas remaining in the fuel generator 2 and the flow path passes through the fuel cell 1 and is discharged to the outside while being pushed by the inert gas while maintaining its temperature substantially. It will be. Therefore, it is conceivable that the inside of the fuel cell 1 is heated only in the portion through which the fuel gas passes.

  When the solid polymer type is used for the fuel cell 1, the solid polymer membrane used for the electrolyte needs to be wet, but an inert gas that is not humidified at high temperature is near the solid polymer membrane. When the gas flows through the solid polymer film, the solid polymer film is partially dried, which significantly reduces the power generation efficiency of the fuel cell 1.

  Next, even if the fuel cell 1 stops power generation, the fuel cell 1 itself maintains a temperature of about 70 ° C. for a while. Since this is a higher temperature than the environmental temperature, the heat held by the fuel cell 1 is only released to the outside after the circulation of the cooling water is stopped, and the heat generated during power generation is effectively utilized. In order to use it, it is necessary to use the heat held by the fuel cell 1 even after power generation.

  The present invention has been made in view of the above problems, and an object of the present invention is to obtain a fuel cell system that does not cause a situation in which the power generation efficiency of the fuel cell is lowered after the end of power generation.

  Another object of the present invention is to provide a fuel cell system that can utilize the heat retained by the fuel cell even after the end of power generation.

A first aspect of the present invention is a polymer electrolyte fuel cell that generates electric power by receiving supply of a fuel and an oxidant;
A cooling circulation system in which a first heat medium supporting the heat of the polymer electrolyte fuel cell, which is provided so as to pass through the polymer electrolyte fuel cell, circulates inside,
First heat medium circulation means for circulating the first heat medium in the cooling circulation system;
A second heat medium path through which the second heat medium flows;
Second heat medium circulating means for flowing a second heat medium in the second heat medium path;
A heat exchanger that exchanges heat between the first heat medium and the second heat medium;
With a controller,
In the fuel cell system, the controller operates the first heat medium circulation unit and the second heat medium circulation unit even after power generation of the polymer electrolyte fuel cell is stopped.

A second aspect of the present invention relates to a polymer electrolyte fuel cell that generates electric power by receiving supply of fuel and an oxidant;
A cooling circulation system in which a first heat medium supporting the heat of the polymer electrolyte fuel cell, which is provided so as to pass through the polymer electrolyte fuel cell, circulates inside,
First heat medium circulation means for circulating the first heat medium in the cooling circulation system;
A second heat medium path through which the second heat medium flows;
Second heat medium circulating means for flowing a second heat medium in the second heat medium path;
A heat exchanger that exchanges heat between the first heat medium and the second heat medium;
With a controller,
In the fuel cell system, the controller operates the first heat medium circulation means and the second heat medium circulation means even after the supply of the fuel and the oxidant to the polymer electrolyte fuel cell is stopped. is there.

  A third aspect of the present invention includes a hot water storage tank for storing city water as a second heat medium that has passed through the heat exchanger, and the first heat medium circulation means and the second heat medium circulation means are in operation. In the fuel cell system according to the first or second aspect of the present invention, city water that has passed through the heat exchanger is supplied to the hot water tank.

A fourth aspect of the present invention relates to a polymer electrolyte fuel cell that generates electric power upon receiving supply of fuel and an oxidant;
A cooling circulation system in which a first heat medium supporting the heat of the polymer electrolyte fuel cell, which is provided so as to pass through the polymer electrolyte fuel cell, circulates inside,
First heat medium circulating means for circulating the first heat medium in the cooling circulation system;
A second heat medium path through which the second heat medium flows;
Second heat medium circulating means for flowing the second heat medium in the second heat medium path;
A method for operating a fuel cell system comprising a heat exchanger that exchanges heat between the first heat medium and the second heat medium,
This is a method of operating a fuel cell system in which the first heat medium circulation means and the second heat medium circulation means are operated even after power generation of the polymer electrolyte fuel cell is stopped.

A fifth aspect of the present invention relates to a polymer electrolyte fuel cell that generates electric power by receiving supply of a fuel and an oxidant;
A cooling circulation system in which a first heat medium supporting the heat of the polymer electrolyte fuel cell, which is provided so as to pass through the polymer electrolyte fuel cell, circulates inside,
First heat medium circulating means for circulating the first heat medium in the cooling circulation system;
A second heat medium path through which the second heat medium flows;
Second heat medium circulating means for flowing the second heat medium in the second heat medium path;
A method for operating a fuel cell system comprising a heat exchanger that exchanges heat between the first heat medium and the second heat medium,
An operation method of a fuel cell system in which the first heat medium circulation means and the second heat medium circulation means are operated even after supply of the fuel and the oxidant to the polymer electrolyte fuel cell is stopped. is there.

  According to a sixth aspect of the present invention, city water as the second heat medium that has passed through the heat exchanger is supplied to the hot water tank when the first heat medium circulation operation and the second heat medium circulation means are operated. The operation method of the fuel cell system according to the fourth or fifth aspect of the present invention.

  As is apparent from the above description, the present invention can provide a fuel cell system that does not cause a situation in which the power generation efficiency of the fuel cell is lowered after the end of power generation.

  Further, it is possible to provide a fuel cell system that efficiently extracts heat generated in the fuel cell to the outside and uses the heat in an effective form.

It is a figure which shows the flowchart which shows the driving | operation form during a power generation of the fuel cell system in the 1st Embodiment of this invention, and after a power generation stop. It is a figure which shows the flowchart which shows the driving | operation form during a power generation of the fuel cell system in the 2nd Embodiment of this invention, and after a power generation stop. It is a block diagram which shows the conventional fuel cell system in embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
The components of the fuel cell system according to the first embodiment of the present invention are shown in FIG. 3 which is the same as the conventional example, and the same components are given the same numbers.

  As shown in FIG. 3, the fuel cell system of the present embodiment includes a fuel cell 1 that generates power using fuel gas and an oxidant, and reforms by adding water to a power generation raw material such as natural gas to form hydrogen. Fuel generator 2 for generating rich fuel gas, blower 3 for supplying air as oxidant to fuel cell 1, and cooling water as fuel for the first heat medium for extracting heat generated by fuel cell 1 to the outside Cooling pipe 4 that circulates to battery 1, cooling water pump 5 that is located in cooling pipe 4 and conveys cooling water, and heat of cooling water as the first heat medium is transferred to city water as the second heat medium. A heat exchanger 6 that stores the city water, a city water pipe 8 that connects the heat exchanger 6 and the water reservoir 7, and a city water pump 9 that conveys the city water.

  FIG. 1 is a flowchart showing an operation mode of the cooling water pump 5 and the city water pump 9 during and after power generation of the fuel cell system according to the first embodiment of the present invention.

  The operation of the fuel cell system according to the present embodiment having the above configuration will be described below.

  The fuel cell 1 generates electric power and heat from the fuel gas rich in hydrogen generated by the fuel generator 2 and the air supplied by the blower 3.

  The fuel generator 2 is maintained at a high temperature (about 700 ° C.) by a burner (not shown) for burning natural gas or the like in order to generate hydrogen-rich fuel gas by adding water to a power generation raw material such as natural gas. Has been.

  Heat generated in the fuel cell 1 is conveyed to the outside by cooling water flowing through the cooling pipe 4. The cooling water flow rate of the cooling water pump 5 is such that the cooling water temperature Tf detected by the fuel cell temperature detector 10 installed where the cooling water flows out of the fuel cell 1 coincides with the target temperature Tr1 (about 70 ° C.). Adjust the transport capacity. Here, since the temperature of the fuel cell 1 is considered to be substantially equal to the temperature flowing out of the fuel cell 1, the temperature detected by the fuel cell temperature detector 10 may be regarded as the temperature of the fuel cell 1.

  The heat obtained by the cooling water is transmitted to the city water flowing through the city water pipe 8 through the heat exchanger 6. The flow rate of the city water is such that the city water temperature Tw detected by the city water temperature detector 11 installed where the city water flows out of the heat exchanger 6 coincides with the target temperature Tr2 (about 60 ° C.). The conveyance capacity of the city water pump 9 is adjusted.

  Next, when the power generation of the fuel cell 1 is terminated, the supply of the raw material gas and water to the fuel generator 2 is stopped, and at the same time, the raw material gas and the fuel gas from the fuel generator 2 to the fuel cell 1 are stopped. An inert gas such as nitrogen is sent to both the distribution path of the fuel cell 1 and the distribution path of the raw material gas and the fuel gas in the fuel cell 1, and the combustible gas remaining in the fuel generator, the distribution path and the fuel cell 1 is converted into Drain from the system.

  The operation so far is the same as that of the conventional fuel cell system, but the subsequent operation will be described with reference to the flowchart of FIG.

  First, the fuel cell temperature detector 10 detects the temperature Tf of the cooling water flowing out from the fuel cell 1 corresponding to the temperature of the fuel cell 1 (001).

  When the detected temperature Tf is higher than the predetermined target temperature Tr1, the cooling water transfer capacity of the cooling water pump 5 is increased. Conversely, when the detected temperature Tf is lower than the target temperature Tr1, the cooling water pump 5 is reduced (002). Here, in order to determine the cooling water conveyance capacity of the cooling water pump 5, the cooling water pump 5 is cooled so that the temperature Tf of the cooling water coincides with the target temperature Tr1 using a commonly used PID controller. The cooling water pump 5 may be operated by calculating the water conveyance power.

  Subsequently, the city water temperature detector 11 detects the temperature Tw of city water flowing out from the heat exchanger 6 (003).

  When the detected temperature Tw is higher than a predetermined target temperature Tr2, the city water pump 9 is increased in the city water transport capacity. Conversely, when the detected temperature Tw is lower than the target temperature Tr2, The city water carrying capacity of the pump 9 is reduced (004). Here, in order to determine the city water transport capacity of the city water pump 9, the city water pump 9 city is set so that the city water temperature Tw matches the target temperature Tr2 using a commonly used PID controller. The city water pump 9 may be operated by calculating the water conveyance power.

  Next, a controller of a system (not shown) determines whether or not the fuel cell system has stopped generating power (005). If power generation is continuing, the process returns to step 002 to repeat the operation based on the above flow.

  On the other hand, when the power generation of the fuel cell 1 is stopped, the supply of fuel gas from the fuel generator 2 and the supply of air from the blower 3 are stopped, and the inert gas to the fuel generator 2 and the fuel cell 1 is stopped. Although the introduction is started, the fuel cell temperature detector 10 compares the temperature Tf of the cooling water with a predetermined threshold temperature Te1 (about 60 ° C.) (006) to determine the temperature Tf of the cooling water. When it is higher than the threshold temperature Te1 (about 60 ° C.), the process returns to the process 002 and the operation based on the above flow is repeated.

  When the temperature Tf of the cooling water is lower than the threshold temperature Te1 (about 60 ° C.), the operation of the cooling water pump 5 and the city water pump 9 is stopped.

  As described above, in the present embodiment, the cooling water pump 5 and the city water pump 9 for conveying the heat generated by the fuel cell 1 to the outside continue to operate even when the fuel cell 1 stops generating power. Even when an inert gas such as nitrogen is sent to the fuel cell 1 through the fuel gas generator 2 and the fuel gas 1 and the fuel gas flow path, the high-temperature residual fuel gas transported by the inert gas and the inert gas remains. Since the retained heat is discharged to the outside through the cooling water, the fuel cell 1 does not partially become hot. Therefore, even if the solid polymer type is used for the fuel cell 1, the situation where the solid polymer membrane is partially dried does not occur, and the situation where the power generation efficiency of the fuel cell 1 is significantly reduced does not occur.

  Further, at the time when the power generation of the fuel cell system is stopped, the cooling water pump 5 and the city water pump 9 continue to operate even when the fuel cell 1 stops generating power, and the cooling water temperature Tf becomes lower than the threshold temperature Te1. By stopping at the time, it becomes possible to efficiently recover the heat generated during the power generation of the fuel cell 1.

  Further, when the temperature Tf of the cooling water is lower than the threshold temperature Te1, the cooling water pump 5 and the city water pump 9 are stopped, so that the temperature of the city water stored in the hot water is not lowered more than necessary. It is possible to maintain city water hot water at a high temperature.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to the drawings.

  Since this embodiment also has the same configuration as that of the conventional fuel cell system as in the first embodiment, FIG. 3 is used for the description, and this detailed description is based on the first embodiment of the present invention. It shall conform to that of the fuel cell system in the embodiment.

  FIG. 2 is a flowchart showing an operation mode of the cooling water pump 5 and the city water pump 9 during and after power generation of the fuel cell system according to the second embodiment of the present invention.

  The operation of the fuel cell system according to the present embodiment having the above configuration will be described below.

  First, the fuel cell temperature detector 10 detects the temperature Tf of the cooling water flowing out from the fuel cell 1 corresponding to the temperature of the fuel cell 1 (001).

  When the detected temperature Tf is higher than the predetermined target temperature Tr1, the cooling water transfer capacity of the cooling water pump 5 is increased. Conversely, when the detected temperature Tf is lower than the target temperature Tr1, the cooling water pump 5 is reduced (002). Here, in order to determine the cooling water conveyance capacity of the cooling water pump 5, the cooling water pump 5 is cooled so that the temperature Tf of the cooling water coincides with the target temperature Tr1 using a commonly used PID controller. The cooling water pump 5 may be operated by calculating the water conveyance power.

  Subsequently, the city water temperature detector 11 detects the temperature Tw of city water flowing out from the heat exchanger 6 (003). When the detected temperature Tw is higher than a predetermined target temperature Tr2, the city water pump 9 is increased in the city water transport capacity. Conversely, when the detected temperature Tw is lower than the target temperature Tr2, The city water carrying capacity of the pump 9 is reduced (004). Here, in order to determine the city water transport capacity of the city water pump 9, the city water pump 9 city is set so that the city water temperature Tw matches the target temperature Tr2 using a commonly used PID controller. The city water pump 9 may be operated by calculating the water conveyance power.

  Then, the controller of the system (not shown) determines whether or not the fuel cell system has stopped generating power (005). If power generation is continuing, the process returns to step 002 to repeat the operation based on the above flow.

  On the other hand, when the power generation of the fuel cell 1 is stopped, the temperature Tw of the city water is compared with a predetermined threshold temperature Te2 (about 55 ° C.) (006) to obtain the temperature Tw of the city water. When the temperature is higher than the threshold temperature Te2 (about 55 ° C.), the process returns to the process 002 and the operation based on the above flow is repeated.

  When the city water temperature Tw becomes lower than the threshold temperature Te2 (about 55 ° C.), the cooling water pump 5 and the city water pump 9 are stopped.

  As described above, in the present embodiment, when the power generation of the fuel cell system is stopped, the cooling water pump 5 and the city water pump 9 for conveying the heat generated by the fuel cell 1 to the outside are the fuel cell 1 Even if power generation is stopped, the system continues to operate and stops when the temperature Tw of the city water becomes lower than the threshold temperature Te2, so that it occurs when the fuel cell 1 generates power. Thus, it is possible to efficiently recover the heat kept in the heat.

  When the city water temperature Tw is lower than the threshold temperature Te2, the cooling water pump 5 and the city water pump 9 are stopped, so that the temperature of the city water stored in the hot water is not lowered more than necessary. It is possible to maintain city water hot water at a temperature with high utility value.

  In addition, since the timing of stopping the cooling water pump 5 and the city water pump 9 is determined by the temperature of the city water that actually uses heat, the hot water storage temperature can be managed accurately.

  Further, as in the first embodiment, when power generation is stopped, the inert gas such as nitrogen is sent to the fuel cell 1 through the fuel gas generator 2 and the fuel gas 1 raw material gas and fuel gas flow paths. In addition, since the heat retained by the high-temperature residual fuel gas conveyed by the inert gas is discharged to the outside through the cooling water, the fuel cell 1 is not partially heated. Therefore, even if the solid polymer type is used for the fuel cell 1, the situation where the solid polymer membrane is partially dried does not occur, and the situation where the power generation efficiency of the fuel cell 1 is significantly reduced does not occur.

  In the first and second embodiments of the present invention, the target temperature Tr1 of the fuel cell 1 is 70 ° C. and the target temperature Tr2 of city water is 60 ° C., but the target temperature Tr1 is the fuel cell 1. It should be set to a temperature at which power generation is efficiently carried out and should not be limited to 70 ° C. The target temperature Tr2 should also be set to a desired temperature for storing city water in the hot water storage tank 7 and limited to 60 ° C. is not.

  In the first embodiment of the present invention, the threshold temperature Te1 for stopping the operation of the cooling water pump 5 and the city water pump 9 is set to 60 ° C., but this is desired as the temperature at which the city water is stored in the hot water storage tank 7. Considering the loss in the heat exchanger 6 to the temperature, it should be set several degrees above and is not limited to 60 ° C.

  Furthermore, in the second embodiment of the present invention, the threshold temperature Te2 for stopping the operation of the cooling water pump 5 and the city water pump 9 is set to 55 ° C., but this is desired as the temperature at which the city water is stored in the hot water storage tank 7. The temperature should be set and is not limited to 55 ° C.

  In each of the above embodiments, the fuel cell 1 is an example of the fuel cell of the present invention, and the cooling pipe 4 is an example of the cooling circulation system of the present invention. The cooling water pump 5 is an example of the heat medium circulating means of the present invention, the heat exchanger 6 and the city water pump 9 are examples of the heat radiating means or the heat exchanger of the present invention, and the fuel cell temperature detector 10 and the city water pump. The water temperature detector 11 is an example of the temperature detecting means of the present invention. Moreover, the cooling water conveyed in the cooling pipe 4 is an example of the first heat medium of the present invention, and the city water conveyed in the city water pipe 8 is an example of the second heat medium of the present invention.

  However, the present invention is not limited to the configuration of the above embodiment, and the temperature detecting means of the present invention may directly measure the temperature of the fuel cell 1 to obtain the temperature. Further, the temperature of the heat exchanger 11 may be measured. The temperature of the city water pipe 8 may be measured. In short, the temperature detection means of the present invention only needs to be able to detect the temperature of the fuel cell directly or indirectly, or to detect the temperature of the second heat medium of the present invention, and is limited by the measurement site. There is nothing.

The first heat medium of the present invention need not be limited to cooling water (H ₂ 0), but may be any other medium that is insulative and can sufficiently carry the heat of the fuel cell, such as antifreeze. .

  Further, the heat dissipating means of the present invention may be configured such that the hot water storage layer 7 and the city water pipe 8 are omitted and the heat exchanger 6 releases heat into the air. In this case, only the pump 5 corresponding to the heat medium circulating means operates until a predetermined threshold value is reached. Further, even if the heat dissipation means is configured to perform an operation for heat dissipation such as circulation of the heat medium, only the heat medium circulation means operates even after the supply of fuel and oxidant to the fuel cell is stopped. It may be a thing.

  In the present invention as described above, after the power generation of the fuel cell 1 is stopped, the temperature Tr of the cooling water becomes lower than the threshold temperature Te1 (about 60 ° C.), or the temperature Tw of city water is the threshold temperature Te2 (about 55). By continuing the operation of the cooling water pump 5 and the city water pump 9 until the temperature becomes lower than (° C.), the heat generated by the fuel cell 1 during power generation can be efficiently recovered. Since the cooling water pump 5 and the city water pump 9 are stopped when the temperature of the cooling water or city water becomes lower than the threshold temperature, the temperature of the stored city water is not lowered more than necessary, and the utility value is reduced. It is possible to maintain city water hot water at a high temperature.

  In addition, since the temperature of the fuel cell 1 is not increased by the inert gas that has passed through the raw material gas and the fuel gas path after the power generation is stopped, the solid polymer film is partially formed even if the solid polymer type is used for the fuel cell 1. Therefore, it is possible to provide a highly reliable fuel cell system without causing a situation in which the power generation efficiency of the fuel cell 1 is significantly reduced.

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Fuel generator 3 Blower 4 Cooling piping 5 Cooling water pump 6 Heat exchanger 7 Hot water tank 8 City water piping 9 City water pump 10 Fuel cell temperature detector 11 City water temperature detector

Claims (6)

A polymer electrolyte fuel cell that generates electric power upon receipt of fuel and an oxidant;
A cooling circulation system in which a first heat medium supporting the heat of the polymer electrolyte fuel cell, which is provided so as to pass through the polymer electrolyte fuel cell, circulates inside,
First heat medium circulation means for circulating the first heat medium in the cooling circulation system;
A second heat medium path through which the second heat medium flows;
Second heat medium circulating means for flowing a second heat medium in the second heat medium path;
A heat exchanger that exchanges heat between the first heat medium and the second heat medium;
With a controller,
A fuel cell system in which the controller operates the first heat medium circulation means and the second heat medium circulation means even after power generation of the polymer electrolyte fuel cell is stopped. A polymer electrolyte fuel cell that generates electric power upon receipt of fuel and an oxidant;
A cooling circulation system in which a first heat medium supporting the heat of the polymer electrolyte fuel cell, which is provided so as to pass through the polymer electrolyte fuel cell, circulates inside,
First heat medium circulation means for circulating the first heat medium in the cooling circulation system;
A second heat medium path through which the second heat medium flows;
Second heat medium circulating means for flowing a second heat medium in the second heat medium path;
A heat exchanger that exchanges heat between the first heat medium and the second heat medium;
With a controller,
A fuel cell system in which the controller operates the first heat medium circulation means and the second heat medium circulation means even after the supply of fuel and oxidant to the polymer electrolyte fuel cell is stopped.   A hot water tank for storing city water as the second heat medium that has passed through the heat exchanger is provided, and passes through the heat exchanger when the first heat medium circulation means and the second heat medium circulation means are in operation. The fuel cell system according to claim 1, wherein the city water is supplied to the hot water tank. A polymer electrolyte fuel cell that generates electric power upon receipt of fuel and an oxidant;
A cooling circulation system in which a first heat medium supporting the heat of the polymer electrolyte fuel cell, which is provided so as to pass through the polymer electrolyte fuel cell, circulates inside,
First heat medium circulating means for circulating the first heat medium in the cooling circulation system;
A second heat medium path through which the second heat medium flows;
Second heat medium circulating means for flowing the second heat medium in the second heat medium path;
A method for operating a fuel cell system comprising a heat exchanger that exchanges heat between the first heat medium and the second heat medium,
A method of operating a fuel cell system in which the first heat medium circulation means and the second heat medium circulation means are operated even after power generation of the polymer electrolyte fuel cell is stopped. A polymer electrolyte fuel cell that generates electric power upon receipt of fuel and an oxidant;
A cooling circulation system in which a first heat medium supporting the heat of the polymer electrolyte fuel cell, which is provided so as to pass through the polymer electrolyte fuel cell, circulates inside,
First heat medium circulating means for circulating the first heat medium in the cooling circulation system;
A second heat medium path through which the second heat medium flows;
Second heat medium circulating means for flowing the second heat medium in the second heat medium path;
A method for operating a fuel cell system comprising a heat exchanger that exchanges heat between the first heat medium and the second heat medium,
A method of operating a fuel cell system, wherein the first heat medium circulation means and the second heat medium circulation means are operated even after the supply of the fuel and the oxidant to the polymer electrolyte fuel cell is stopped.   The city water as the second heat medium that has passed through the heat exchanger is supplied to the hot water tank during the operation of the first heat medium circulation operation and the second heat medium circulation means. 6. A method for operating the fuel cell system according to 5.

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