JP4689305B2 - Fuel cell power generation system and control method thereof - Google Patents

Description

  The present invention relates to a fuel cell power generation system having a fuel cell main body, a gas supply means, and a temperature maintenance means, and a control method therefor.

  Conventionally, a fuel cell is known as a system for directly converting chemical energy of a fuel into electricity. This fuel cell is the one that takes out electricity directly by electrochemically reacting hydrogen as fuel and oxygen as oxidant, and can take out electric energy with high efficiency, and at the same time, quiet and harmful exhaust gas It has a feature that is excellent in environmental characteristics that it does not emit. As such a fuel cell, relatively large PAFC (phosphoric acid type) has been mainly developed until recently, but recently, development of a small PEFC (individual polymer fuel cell) has been activated. The spread of household fuel cell power generation systems is also approaching.

  By the way, since this domestic fuel cell power generation system has water inside, there is a possibility of freezing when the storage is stopped under freezing. For this reason, especially when installing in a cold region, some countermeasure against freezing is required. Conventionally, as a countermeasure against such freezing, methods such as using a space heater inside the package or draining water from a water tank when there is a risk of freezing have been generally adopted.

  FIG. 8 is a block diagram showing a configuration of a conventional typical hydrogen fuel utilization type fuel cell power generation system. Hereinafter, the fuel cell power generation system will be described in the order of configuration, operation, and effect.

  In FIG. 8, reference numeral 1 denotes a fuel cell package in which the configuration of the entire fuel cell power generation system is packaged by an outer case, a cover, or the like. The fuel cell package 1 includes a fuel cell main body 2 that generates DC power, a reformer 3 that generates hydrogen using the burner combustion heat of exhaust gas from the fuel cell main body 2, and burner combustion of the reformer 3. A steam generator 4 that generates steam using the exhaust gas, a condenser 5 that condenses moisture in the burner combustion exhaust gas after the steam generation, an exhaust port 6 that discharges the exhaust gas to the outside of the fuel cell package 1, and condensed water A water tank 7 for storage is installed.

  Here, the reformer 3 constitutes a hydrogen supply system that supplies the generated hydrogen to the fuel cell main body 2 and is necessary for power generation together with an oxygen supply system (not shown) that supplies oxygen to the fuel cell main body 2. A gas supply system for supplying various gases. The portion from the reformer 3 to the water tank 7 constitutes an exhaust gas system that uses the exhaust gas from the fuel cell body 2 and discharges the exhaust gas after use.

  The fuel cell package 1 also includes a battery cooling water pump 8 for circulating the battery cooling water, and a battery cooling water heat exchanger 9 for adjusting the battery temperature by recovering the heat generated in the fuel cell body 2. Is installed. Here, the battery cooling water pump 8 and the battery cooling water heat exchanger 9 together with the water tank 7 constitute a battery cooling system for appropriately maintaining the temperature of the fuel cell main body 2.

  Further, as a countermeasure against freezing, water stored in the water tank 7 is discharged to the outside of the fuel cell package 1 via the water discharge shutoff valve 10, and the water tank 7 is used to determine the possibility of freezing. A temperature sensor 12 is installed to measure the temperature.

  The basic operation of this fuel cell power generation system is as follows. During normal operation, the exhaust heat generated by the power generation of the fuel cell main body 2 is mainly removed by the cooling water circulated by the battery cooling water pump 8, and further, a heat utilization system not described by the battery cooling water heat exchanger 9 is used. It is effectively used by moving to. Further, the reformer exhaust gas after burning surplus hydrogen that has come out of the fuel cell main body 2 is cooled through the steam generator 4 and the condenser 5, and the condensed water generated in the process is led to the water tank 7. It is burned.

  On the other hand, when the power generation is stopped, most of the water is returned to the water tank 7 and retained. However, when the indicated value of the temperature sensor 12 is equal to or lower than the temperature that may freeze, the water discharge is cut off. The valve 10 is opened, and the water in the water tank 7 is discharged to the outside of the fuel cell package 1 through the water discharge line 11.

Thereby, when it becomes an environment with a freezing risk, it becomes possible to prevent freezing by discharging the water in the system. Patent document 1 is typical of such a system. Patent Document 2 proposes a method for preventing freezing using hot water in a hot water tank installed outside a fuel cell package. Furthermore, it is generally performed to provide a heater and a thermometer for preventing freezing in the fuel cell package and to keep the inside of the package at a constant level or more.
JP 11-273704 A JP2003-272687A

  However, the conventional anti-freezing method of the fuel cell power generation system as described above has the following problems.

  First, although the method of draining water from the water tank is effective in preventing freezing, it is necessary to perform water filling again at the next power generation start, which causes a problem that the water treatment load increases. Considering the ongoing efforts to reduce the water treatment load, which accounts for the majority of maintenance costs, in the field of fuel cell system development, the countermeasure against freezing by draining water from the water tank is It goes against the flow.

  In addition, the method of preventing freezing using hot water in a hot water tank is not a problem as long as the heat stored in the hot water is in excess, but since there is little possibility of heat remaining in the period when normal freezing is a concern, this method is Eventually it leads to energy loss and is not ideal.

  Furthermore, the method of controlling the temperature by providing a freezing prevention heater and thermometer in the package means that the heater control is always performed when the storage is stopped at a low outside air temperature. There is a problem that energy loss cannot be ignored.

  The present invention has been proposed in order to solve the above-described problems, and the purpose thereof is to discharge water to the outside of the system without using constant heater control or heat storage in a hot water tank. It is also to provide an energy efficient fuel cell power generation system capable of realizing effective freezing countermeasures and a control method therefor.

  In order to achieve the above object, the present invention introduces water inside the system into the water tank when power generation is stopped, and transfers the heat generated inside the system to the water tank when power generation is started. An effective anti-freezing measure can be realized without using any heater control or heat storage in a hot water storage tank and without discharging water outside the system.

A fuel cell power generation system according to the present invention includes a fuel cell main body, a gas supply means for supplying hydrogen and oxygen to the fuel cell main body, a temperature maintaining means for appropriately maintaining the temperature of the fuel cell main body, and a water tank for storing water In the fuel cell power generation system having the above, the water tank is arranged below the fuel cell main body, and has the following water introduction means and heat transfer means. That is, the water introduction means is means for introducing water held in any one or more of the fuel cell main body, the gas supply means, and the temperature maintenance means to the water tank when power generation is stopped. Further, the heat transfer means, during power generation startup, when the water in the water tank is frozen, I means der for thawing frozen water the heat generated within the system is transmitted to the water tank, the water tank Has a heater for thawing frozen water provided in the interior of the system, and in addition to the heat generated inside the system, start-up priority operation that forcibly thaws frozen water by heating the water tank with the heater, and occurs inside the system It is a means comprised so that either operation | movement of the energy-saving priority operation | movement which thaws frozen water using only the heat which carried out may be performed.

  The control method of the present invention grasps the characteristics of the fuel cell power generation system from the viewpoint of a method for controlling the system.

  According to the fuel cell power generation system having the above features and the control method thereof, when the power generation is stopped, the heat generated in the system is transferred to the water tank by collecting the water inside the system in the water tank. By only taking measures against freezing, measures for freezing the entire system can be easily realized. That is, even when the water in the water tank is frozen during storage, the heat generation generated in the system at the time of starting the power generation is transmitted to the water tank, so that the power generation can be started from the frozen state with a small energy loss.

  On the other hand, another fuel cell power generation system of the present invention recovers heat generated in the fuel cell main body by circulating antifreeze liquid in the fuel cell power generation system having the fuel cell main body, gas supply means, and temperature maintaining means. It has a heat storage means for storing in the heat storage.

  According to the fuel cell power generation system having such characteristics, the heat generated in the fuel cell body is recovered by the antifreeze liquid, so that the antifreeze liquid itself serving as a heat medium does not freeze. The heat stored in the heat accumulator can be transferred into the system simply by circulating the antifreeze liquid, and a countermeasure for freezing of the entire system can be easily realized.

  According to the present invention, the water inside the system is introduced into the water tank when the power generation is stopped, and the heat generated inside the system is transmitted to the water tank when the power generation is started. It is possible to provide a fuel cell power generation system excellent in energy efficiency and its control method capable of realizing an effective anti-freezing measure without using water and without discharging water to the outside of the system.

  Embodiments to which the present invention is applied will be specifically described below with reference to the drawings. From the viewpoint of simplifying the explanation, the same parts as those in the prior art shown in FIG.

[First Embodiment]
[System configuration]
FIG. 1 is a block diagram showing a fuel cell power generation system according to a first embodiment to which the present invention is applied. The basic configuration of the present embodiment is the same as that of the prior art shown in FIG. 8, except for the following points.

  That is, as shown in FIG. 1, in the present embodiment, first, in place of the condenser 5 and the water tank 7 of FIG. 8, a composite condenser in which a condenser portion 20 a and a water tank portion 20 b are integrally configured up and down. 20 is provided. The composite condenser 20 is arranged such that the position of the water tank portion 20 b is lower than the fuel cell main body 2.

  Further, since the fuel cell power generation system of this embodiment is not a method of discharging water to the outside but a method of collecting water in the water tank portion 20b of the composite condenser 20, the water discharge cutoff valve 10 and the water in FIG. The discharge line 11 is not provided, but instead, an air introduction shutoff valve 30 is provided for extracting water from the fuel cell main body 2 by introduction of air and introducing it into the water tank portion 20b.

  As described above with reference to FIG. 8, the reformer 3 generates power together with a hydrogen supply system that supplies hydrogen to the fuel cell body 2 and an oxygen supply system (not shown) that supplies oxygen to the fuel cell body 2. A gas supply system for supplying necessary gas is configured, and this gas supply system corresponds to the gas supply means in the present invention. The battery cooling water pump 8 and the battery cooling water heat exchanger 9 together with the composite condenser 20 including the water tank portion 20b constitute a battery cooling system for appropriately maintaining the temperature of the fuel cell main body 2. This battery cooling system corresponds to the temperature maintaining means in the present invention.

  Furthermore, each part of the fuel cell power generation system as described above is controlled by a control command from the system control device 100. Here, the system control apparatus 100 is specifically realized by a microcomputer storing a program specialized for controlling the fuel cell power generation system according to the present invention.

[Composite condenser]
FIG. 2 is a schematic diagram showing the configuration of the composite condenser 20 of the present embodiment. As shown in FIG. 2, in the composite condenser 20, the shape of the inner peripheral surface of the water tank portion 20b is such that the cross-sectional area of the inner space defined by the inner peripheral surface is continuously from the lower end toward the information. It is supposed to be a larger shape. Specifically, it can be considered to have a downward substantially conical shape, a substantially polygonal pyramid shape, a substantially truncated cone shape, a substantially polygonal frustum shape, etc., but here, as an example, a downward substantially square pyramid shape It shall be a shape.

  A latent heat storage material 21 having a melting point of 10 ° C. is attached to the inner peripheral surface of the water tank portion 20b. The latent heat storage material 21 is a heat storage material using latent heat represented by the product of the mass of the phase change material and the solidification / melting latent heat per unit mass, and various existing latent heat storage materials can be used. In addition, melting | fusing point 10 degreeC of the latent heat storage material 21 is an example, and melting | fusing point of the latent heat storage material 21 can be freely changed according to the environment where a fuel cell power generation system is installed, the type of system, etc. Conventionally, various latent heat storage materials have been proposed in which the melting point can be freely set by adjusting the composition of the substances. By using such materials, the melting point of the latent heat storage material 21 can be easily changed. It is.

  Further, on the inner surface of the latent heat storage material 21, a thawing heater 22 for thawing frozen water when water in the water tank portion 20b is frozen and a temperature sensor 12 for measuring the temperature of the water tank portion 20b are attached. Yes.

  Further, on the side surface of the composite condenser 20, a combustion exhaust gas inlet 23 for introducing the burner combustion exhaust gas of the reformer 3 is provided in the vicinity of the upper portion of the latent heat storage material 21 of the water tank portion 20 b. A combustion exhaust gas outlet 24 for discharging the introduced burner combustion exhaust gas is provided on the upper surface.

  Further, in the internal space of the water tank 20b below the composite condenser 20, heat transfer from the burner combustion exhaust gas introduced from the combustion exhaust gas inlet 23 is promoted, and heat energy is transferred to the water stored in the water tank 20b. A heat transfer promoting material 25 is provided for efficient transmission. Here, the heat transfer promoting material 25 is specifically a heat transfer fin formed of a metal plate having high thermal conductivity such as aluminum or copper. The heat transfer promoting material 25 is fixed to the upper surface of the composite condenser 20 via a flexible support member 26, and the deformation and deformation of the support member 26 are used for the bottom surface and the side surface of the composite condenser 20. Can be displaced.

  Further, in the internal space of the condenser section 20a above the composite condenser 20, a heat source 27 for cooling and condensing the heat of the burner combustion exhaust gas and taking it out as hot water is installed above the heat transfer promoting material 25. Has been.

  A heat insulating material 28 is provided around the composite condenser 20 in order to suppress heat radiation to the outside.

[Suspended storage start procedure]
FIG. 3 is a flowchart showing the stop storage start procedure of the fuel cell power generation system according to this embodiment having the above-described configuration.

  As shown in FIG. 3, when a power generation stop command is issued from the power generation state (YES in S110), the system control device 100 performs a power supply stop process by supplying a gas supply system that supplies hydrogen and oxygen to the fuel cell body 2 ( The power generation is stopped by closing the power generation of the fuel cell body 2 by closing the parts other than the reformer 3 (S120). Subsequently, as the water introduction process, the water extracted from the fuel cell main body 2 is combined by removing the water from the fuel cell main body 2 while opening the shut-off valve 30 and introducing the air and causing the battery cooling water pump 8 to flow backward. The water is forcedly introduced into the water tank 20b of the condenser 20 (S130). As a result, the fuel cell power generation system is completely stopped and stored.

  Further, when a power generation start command is issued from the storage state (YES in S140), the start processing in one of the start priority mode and the energy saving priority mode is performed based on the prior mode setting or mode selection condition (S150). It performs (S160, S170). In this activation process, the reformer 3 is activated and heated to transfer heat to the water tank 20b of the composite condenser 20, so that the water in the water tank 20b is frozen. When the frozen water is thawed and the reforming is started by introducing steam when the temperature rise of the reformer 3 is completed, the power generation start-up is completed and a normal power generation state is achieved.

[Action]
Hereinafter, the operation of the fuel cell power generation system according to the present embodiment as described above will be described.

[Basic action by water introduction / start-up process]
In the stop procedure of the present embodiment, as described above, after the power generation is stopped by the gas supply stop process (S120), as the water introduction process, water is supplied from the fuel cell main body 2 while opening the shut-off valve 30 and introducing air. The water extracted from the fuel cell body 2 is forcibly introduced into the water tank 20b of the composite condenser 20 by removing the battery cooling water and causing the battery cooling water pump 8 to flow backward (S130).

  In this embodiment, by collecting the water inside the system in the water tank portion 21b as described above, the entire system can be obtained only by taking a simple countermeasure against freezing in which the heat generated inside the system is transmitted to the water tank portion 21b. Can be easily realized. That is, even when the water in the water tank portion 21b is frozen during storage, the heat of the combustion exhaust gas generated in the reformer 3 inside the system at the time of power generation startup is transferred to the water tank portion 21b, thereby freezing with less energy loss. Power generation can be started from the state.

[Freezing delay due to latent heat storage material]
In addition, when the water introduction process is performed when power generation is stopped, the water in the water tank section 20b is about 60 ° C. In this case, the latent heat storage material 21 having a melting point of 10 ° C. is stored in a liquid form. After this, when the outside air temperature becomes below freezing and the environment becomes a freezing risk environment, the water in the water tank gradually decreases in the conventional system and starts freezing after a certain period of time. Since it has the latent heat storage material 21, as shown in FIG. 4, it can hold | maintain the water temperature which does not freeze over longer time compared with the past.

  Therefore, in the case of DSS (Daily startup shutdown) operation in which the vehicle is operated during the daytime and stopped at night, there is a high possibility that it can be connected to the next startup without freezing water. As described above, according to the fuel cell power generation system of the present embodiment, it is possible to realize an effective freezing measure such as a freezing delay due to water temperature maintenance during DSS operation.

[Expansion absorption by water tank shape]
As described above, in this embodiment, although the freezing delay action by the latent heat storage material 21 can be obtained, the water in the water tank 20b is frozen when placed in a freezing risk environment below freezing for a long time. become. In the conventional water tank shape, there is a possibility that the tank may be damaged due to the expansion during the freezing. In the present embodiment, the shape of the water tank portion 20b is a downward substantially square frustum shape. Therefore, even if it freezes, the expansion part can escape upwards, and the water tank part 20b is not damaged. Thus, according to the fuel cell power generation system of this embodiment, the amount of expansion during freezing of water can be absorbed by devising the shape of the inner peripheral surface of the water tank portion 20b.

  Moreover, since the heat transfer promotion material 25 installed in the water tank portion 20b can be displaced with respect to the bottom surface and the side surface of the composite condenser 20 by a flexible support member 26, with the freezing of water. Since it can be displaced without hindrance, the heat transfer promoting material 25 is not damaged.

  As described above, the shape of the inner peripheral surface of the water tank portion 20b is not limited to the downward substantially square frustum shape, but is the downward substantially conical shape, substantially polygonal pyramid shape, substantially truncated cone shape, and substantially polygonal frustum shape. It is also possible to have a shape such as a shape. That is, if the cross-sectional area of the internal space defined by the inner peripheral surface of the water tank portion 20b is a shape that continuously increases from the lower end toward the information, the same action can be obtained. Alternatively, instead of devising the shape of the water tank portion 20b, a part or all of the inner peripheral surface of the water tank portion 20b can be deformed to provide an expansion absorbing function by deformation. Good.

[Suppression of energy loss by startup processing in startup priority mode]
FIG. 5 is a flowchart showing the procedure of the startup priority mode startup process (S160) shown in FIG.

  As shown in FIG. 5, in the startup process of the startup priority mode, first, based on the instruction value of the temperature sensor 12, it is determined whether or not the water tank unit 20b is in a frozen state (S161). When it is not frozen (NO in S161), as a normal start-up process, the reformer 3 is ignited and heated (S162), and steam is generated when the temperature of the reformer is completed (S163). The steam generated in the generator 4 is introduced into the reformer 3 to start reforming (S164), whereby the power generation start-up is completed and a normal power generation state is obtained. On the other hand, when it is determined that it is in a frozen state (YES in S161), frozen water thawing activation processing is performed (S165 to S169).

  That is, in the frozen water thawing start-up process, first, the reformer 3 is ignited and heated, and the burner combustion air is increased (S165). In this case, the burner combustion exhaust gas of the reformer 3 is introduced from the combustion exhaust gas inlet 23 of the composite condenser 20, heated to the frozen water by the heat transfer accelerator 25, and then discharged from the combustion exhaust gas outlet 24. Thus, the heat of the burner combustion exhaust gas is transmitted to the water tank 20b (S166, heat transfer operation). In this case, since the burner combustion air is increased as compared with the normal startup process, heat transfer from the burner combustion exhaust gas to the water tank 20b is promoted, and thawing is efficiently performed.

  When the temperature of the reformer 3 reaches the temperature increase completion condition temperature minus 100 ° C. (S167), it is determined whether or not the temperature of the water tank portion 20b is 4 ° C. or higher based on the indication value of the temperature sensor 12. As a condition, it is determined whether or not the water in the water tank 20b has been thawed (S168).

  When the thawing is completed (YES in S168), the process thereafter proceeds to a normal startup process, and the steam generated by the steam generator 4 is modified when the temperature raising of the reformer is completed (S163). The reformer is started after being introduced into the mass device 3 (S164). If the thawing is not completed (NO in S168), the thawing heater 22 is energized to “Active” and the forced thawing is performed (S169).

  Such forced thawing by the thawing heater 22 leads to energy loss due to power consumption of the thawing heater, but this situation is essentially rare, and thawing has progressed to some extent by the burner combustion exhaust gas of the reformer. Since the heater is turned on from the state, the energy loss due to the thawing heater can be kept low. Moreover, the starting time at the time of freezing can be shortened as much as possible compared with the case where a thawing heater is not used.

[Minimization of energy loss by activation process of energy saving priority mode]
FIG. 6 is a flowchart showing the procedure of the energy saving priority mode start-up process (S170) shown in FIG.

  As shown in FIG. 6, in the start-up process of the energy saving priority mode, the reformer 3 is ignited and heated (S171), so that the burner combustion exhaust gas is obtained when the water tank portion 20b is frozen. Is transferred to the frozen water by the heat transfer promoting material 25, and the frozen water is thawed efficiently (S172, heat transfer operation). Then, when the temperature raising of the reformer is completed (S173), based on the indication value of the temperature sensor 12, whether or not the temperature of the water tank 20b is 4 ° C. or higher is set as a determination condition. It is determined whether or not the water inside has been thawed (S174).

  When the thawing is completed (YES in S174), the steam generation generated by the steam generator 4 is introduced into the reformer 3 to start reforming (S175). It becomes the power generation state. If thawing has not been completed (NO in S174), the thawing operation is performed by reducing the fuel supply amount and increasing the air supply amount without using the thawing heater 22 (S176). (YES in S174), the heat transfer operation by burner combustion is continued.

  Such a method that does not use the thawing heater 22 may have a longer start-up time than the case where forced thawing is performed by the thawing heater 22, but the energy loss is further increased by the amount that the thawing heater 22 is not used. It can be kept low and minimized.

[effect]
The effects of the fuel cell power generation system according to this embodiment as described above are as follows. In other words, even during DSS operation in a freezing risk environment, the possibility and frequency of freezing can be kept low, and in the unlikely event of freezing, the composite condenser and other equipment including the water tank section will be damaged. In addition, the energy for thawing at the start-up after freezing can be kept low. Therefore, effective countermeasures against freezing can be realized without using constant heater control or heat storage in a hot water storage tank and without discharging water to the outside of the system.

[Second Embodiment]
FIG. 7 is a block diagram showing a fuel cell power generation system according to a second embodiment to which the present invention is applied. The basic configuration of the present embodiment is the same as that of the prior art shown in FIG. 8, except for the following points.

  That is, as shown in FIG. 7, in the present embodiment, a heat storage device 40 that adds heat generated in the fuel cell main body 2 via the battery cooling water heat exchanger 9 by circulating the heat storage material is added. Yes. The heat storage device 40 includes a heat storage tank 41 filled with a heat storage material to store heat, and a heat storage material circulation pump 42 for circulating the heat storage material. In addition, as the heat storage material, a heat storage material made of an antifreeze liquid having a higher specific heat than water and a low freezing point is used.

  The heat storage device 40 further includes a hot water supply line 43, a bath storage line 44, and a bath storage pump 45 in order to supply the heat storage to two heat utilization destinations such as hot water supply and bath storage.

  Further, since the fuel cell power generation system of the present embodiment is not a method of discharging water to the outside but a method of collecting water in the water tank 7, the water discharge cutoff valve of FIG. 8 is similar to the first embodiment. 10 and the water discharge line 11 are not provided.

  In FIG. 7, the configuration of the fuel cell package 1 clarifies the characteristics of the present embodiment, and from the viewpoint of simplification, the reformer 3, the steam generator 4, the condenser 5, and the exhaust gas. Although the description of the opening 6 and the like is omitted, these components 3 to 6 are provided in the actual fuel cell package 1 as in FIG.

  In the present embodiment having the above configuration, the heat generated in the fuel cell main body 2 is recovered by the heat storage material of the heat storage device 40 via the battery cooling water heat exchanger 9 and stored in the heat storage tank 41. The heat stored in the heat storage tank 41 is supplied to two heat utilization destinations, hot water supply and bath remedy, by a hot water supply line 43, a bath remedy line 44, and a bath remedy pump 45. Further, by circulating the heat storage material, the heat stored in the heat storage tank 41 can be transmitted to the battery cooling water via the battery cooling water heat exchanger 9 or can be transmitted to the water tank 7.

  As described above, in the present embodiment, the heat generated in the fuel cell main body is recovered by the heat storage material made of the antifreeze liquid, so that the heat storage material itself that becomes the heat medium does not freeze, so that the heat storage device 40 thaws. It is possible to reduce the energy loss such as the heat storage material 41. By simply circulating the heat storage material, the heat stored in the heat storage tank 41 can be transferred into the fuel cell power generation system, and the entire system can be easily frozen. Can do.

  In particular, according to the present embodiment, by using a heat storage material having a low freezing point and a large heat capacity, the heat storage tank 41 can be reduced in size and freezing can be essentially prevented.

[Other Embodiments]
It should be noted that the present invention is not limited to the above-described embodiments, and various other variations can be implemented within the scope of the present invention.

  That is, the present invention is characterized by a method for treating water held in the system, a method for transferring heat to the water in the system, or a method for collecting and storing heat generated in the system. As long as it has the characteristics of the present invention, the configuration of each part can be freely selected, and even in that case, excellent effects can be obtained as in the above-described embodiment.

1 is a block diagram showing a fuel cell power generation system according to a first embodiment to which the present invention is applied. The schematic diagram which shows the structure of the composite condenser shown in FIG. The flowchart which shows the stop storage starting procedure of the fuel cell power generation system shown in FIG. The graph which shows the temperature behavior of the composite condenser shown in FIG. The flowchart which shows the procedure of the starting process of the starting priority mode shown in FIG. The flowchart which shows the procedure of the starting process of the energy saving priority mode shown in FIG. The block diagram which shows the fuel cell power generation system which concerns on 2nd Embodiment to which this invention is applied. The block diagram which shows the structure of the conventional typical fuel cell power generation system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell package 2 ... Fuel cell main body 3 ... Reformer 4 ... Steam generator 5 ... Condenser 6 ... Exhaust port 7 ... Water tank 8 ... Battery cooling water pump 9 ... Battery cooling water heat exchanger 10 ... Water discharge Shut-off valve 11 ... water discharge line 12 ... temperature sensor 20 ... composite condenser 20a ... condenser part 20b ... water tank part 21 ... latent heat storage material 22 ... thaw heater 23 ... combustion exhaust gas inlet 24 ... combustion exhaust gas outlet 25 ... acceleration of heat transfer Material 26 ... Supporting member 27 ... Cooling heat source 28 ... Heat insulating material 30 ... Shut-off valve 40 ... Thermal storage device 41 ... Thermal storage tank 42 ... Thermal storage material circulation pump 43 ... Hot water supply line 44 ... Bath memorial line 45 ... Bath memorial pump 100 ... System Control device

Claims (8)

In a fuel cell power generation system having a fuel cell main body, a gas supply means for supplying hydrogen and oxygen to the fuel cell main body, a temperature maintaining means for appropriately maintaining the temperature of the fuel cell main body, and a water tank for storing water ,
The water tank is disposed below the fuel cell body,
Water introduction means for introducing water held in any one or more of the fuel cell main body, the gas supply means, and the temperature maintenance means into the water tank when power generation is stopped;
During power generation startup, when the water in the water tank is frozen, it has a heat transfer means for thawing the frozen water the heat generated within the system is transmitted to the water tank,
The heat transfer means has a heater for thawing frozen water provided inside the water tank, and in addition to the heat generated inside the system, the water tank is heated by the heater to force frozen water. A fuel cell power generation that is configured to perform either a startup priority operation for thawing or an energy saving priority operation for thawing frozen water using only heat generated in the system. system. The gas supply means has a combustor that burns the exhaust gas of the fuel cell main body in order to generate heat used to generate hydrogen,
2. The fuel cell power generation according to claim 1, wherein the heat transfer unit includes a composite condenser in which a condenser for condensing moisture in exhaust gas from the combustor and the water tank are integrally configured. system. 3. The fuel cell according to claim 1, wherein the heat transfer means includes a heat transfer promoting member that is provided inside the water tank and promotes heat transfer from the exhaust gas of the combustor. 4. Power generation system. The fuel cell power generation according to any one of claims 1 to 3, wherein the heat transfer means includes a latent heat storage material provided on an inner peripheral surface that defines an internal space of the water tank. system. The water tank, the fuel cell power generation according to any one of claims 1 to 4, characterized in that it has an expansion absorbing means for absorbing the expansion caused by freezing of the water stored in the inner space system. The water tank, the cross-sectional area of the inner space is from the lower portion and continuously larger shape upward, claim 5, characterized in that said expansion absorbing means by the tank shape is configured The fuel cell power generation system described in 1. Shape of the inner peripheral surface of the water tank, downward substantially conical, substantially pyramidal shape, a substantially truncated cone shape, substantially truncated pyramid shape, as claimed in claim 6, characterized in that either Fuel cell power generation system. A fuel cell power generation system having a fuel cell main body, a gas supply means for supplying hydrogen and oxygen to the fuel cell main body, a temperature maintaining means for appropriately maintaining the temperature of the fuel cell main body, and a water tank for storing water In the control method,
The water tank is disposed below the fuel cell body,
A water introduction process for introducing water held in any one or more of the fuel cell main body, the gas supply means, and the temperature maintaining means into the water tank by water introduction means when power generation is stopped;
At the time of power generation start-up, when the water in the water tank is frozen by the heat transfer means, a heat transfer process for transferring the heat generated in the system to the water tank and thawing the frozen water is performed.
In the heat transfer process, in addition to the heat generated in the system, the water tank is heated by a heater to forcibly defrost frozen water, and the frozen water is generated using only the heat generated in the system. A control method for a fuel cell power generation system, wherein any one of energy-saving priority operations for thawing is performed.

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