JP2007052981A - Fuel cell power generation system and its operation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance power generation efficiency in DSS operation of a household fuel cell and to enhance an availability factor of a system. <P>SOLUTION: The fuel cell power generation system is equipped with a fuel cell 9, a cell cooling system having a cooling water tank 10 for cooling the fuel cell 9 during operation, and an exhaust heat recovery system recovering heat from exhaust heats 14, 15a from the cell exhaust gas and the cooling water 12 in the cell cooling water system to make hot water, and the hot water made by heat recovery is stored in a hot water storage tank 18. The hot water in the hot water storage tank 28 is guided to a cooling water tank 10 through hot water supply piping (a hot water supply line for starting) 40 by utilizing the difference of elevation. Since the temperature of cooling water 13 in the fuel cell during stop of operation is decreased, before start of the operation, hot water in the hot water storage tank 8 is supplied to the cooling water tank 10 to heat the cooling water, and thereby, the starting time of the fuel cell 9 is shortened. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a small power supply system using a fuel cell as a main power source, and more particularly to a solid polymer type household fuel cell power hot water supply system.

  A stationary fuel cell for home use is a so-called cogeneration system that not only supplies electricity by power generation by a fuel cell, but also collects exhaust heat from the cell and reformer to produce hot water. Generally, a household fuel cell system is operated at a temperature of 60 to 80 degrees, and heat generated in the battery during power generation is cooled by cooling water. The heat recovered in the cooling water is further recovered as hot water by a heat exchanger provided in the exhaust heat recovery system and sent to a hot water storage tank. Moreover, the cooling water after heat exchange is cooled and used again for cooling the battery. Accordingly, when the hot water tank is filled with hot water, the circulation pump of the exhaust heat recovery system stops, so that the battery cannot be cooled, and the system operation is stopped.

  DSS (Daily Start up & Shut down) operation, which is one of the operation methods, is started and stopped during the day system operation, unlike day and night continuous operation. In particular, at the time of start-up, it is necessary to raise the temperature of the battery and the reformer to a predetermined operating temperature. In the case of the battery, the temperature must be raised from room temperature to around the operating temperature of 60-80 degrees.

  As a conventional example regarding the temperature raising means at the time of startup, the hot water in the hot water circulation system in the hot water tank is circulated through the battery cooling water cooler to exchange heat with the battery cooling water in the battery cooling water circulation system. There is a technique in which the temperature of the battery body is raised by causing the battery body to flow through the cooling channel of the battery cell (Patent Document 1).

JP 2004-039430 A

  By the way, the consumption of hot water, which is a heat demand for home use, may not be well balanced with the power demand depending on the season, and the power demand is lower than the heat recovery amount even though the power demand is larger than the power generation amount. Especially in summer, the amount of hot water used is drastically reduced compared to the use of electric power, the hot water storage tank becomes full in a short operation time, and there is a situation where the power generation operation must be stopped despite the power load. As a result, the system operating rate decreases, the operating rate of battery operation does not increase, and the power contribution rate decreases.

  Moreover, when the level of hot water in the hot water tank becomes higher, a method is taken in which the amount of power generation is suppressed to reduce the amount of hot water generated and the operation time is extended. Such a low-load operation has low power generation efficiency, and it cannot be denied that the daily power generation efficiency is disadvantageous. On the other hand, a method of continuing operation by dissipating heat outside the system without recovering the exhaust heat of the battery is also conceivable, but contrary to the intention of home cogeneration for effective heat utilization. Become.

  In particular, when performing DSS operation, with the conventional method, every time the system is started, the power supplied from outside becomes 1 kWh or more, resulting in an increase in system auxiliary equipment loss, which is a major factor in reducing the average power generation efficiency throughout the day. It was.

  Since DSS operation also adversely affects environmental performance such as power generation efficiency, energy saving, and carbon dioxide reduction, effective utilization of hot water is desired in addition to user demand.

  In order to realize DSS operation with high power generation efficiency in terms of system operation, it is considered that a battery temperature raising method and a fuel cell power generation system with high energy saving performance are necessary at the time of system startup. The temperature raising means of the prior art is configured to indirectly exchange heat between the hot water in the hot water storage tank and the cooling water in the cooling water circulation system with a cooling water cooler, so that the water temperature in the cooling water tank is reduced. The climb could not be done in a short time.

  The object of the present invention is to increase the operating rate of the system by extending the time when the hot water tank is full as much as possible in view of the problems of the prior art, and to increase the water temperature in the cooling water tank at startup. It is to provide a fuel cell power generation system that can be shortened.

  Also, increase the average power generation efficiency of the day by increasing the time of high load operation with high power generation efficiency as much as possible, or by increasing the battery temperature without using external energy as much as possible at the time of start-up. An object is to provide a fuel cell power generation system.

  In the present invention for solving the above-described problems, hot water remaining in the hot water tank at the time of cold start is supplied to the battery cooling water system of the fuel cell and used for battery temperature rise at the time of system start.

  That is, the fuel cell power generation system of the present invention includes a fuel cell, a battery cooling water system that cools the fuel cell, exhaust heat from the battery exhaust gas, and exhaust heat that recovers heat from the cooling water of the battery cooling water system to produce hot water. A system having a recovery system and a hot water storage tank for storing hot water produced by heat recovery, comprising a hot water supply pipe for guiding the hot water of the hot water storage tank to the battery cooling water system, and increasing the startup time of the fuel cell It is characterized in that it can be shortened.

  The hot water supply pipe is configured to supply hot water from the hot water storage tank to a cooling water tank of the battery cooling water system using a height difference.

  In addition, a heat exchanger is provided for heating the hot water used for raising the temperature of the fuel cell using exhaust heat discharged from the fuel processing device (reformer), and the temperature of the fuel cell is raised again. It is configured so that it can be performed.

  Alternatively, a drain line for discharging the cooling water of the battery cooling water system before starting, a hot water supply pipe for supplying hot water of the hot water storage tank to a cooling water tank of the battery cooling water system, and the fuel from the cooling water tank A circulation pump that supplies hot water to the battery, and a heat exchanger that exchanges heat between the hot water from the fuel cell outlet and the exhaust gas from the fuel processing device (reformer) are provided, and the heated hot water is returned to the cooling water tank again. It is characterized by returning.

  The operation method of the present invention has a battery cooling water system for cooling a fuel cell, an exhaust heat recovery system for producing hot water by recovering heat from the exhaust heat from the battery exhaust gas and from the cooling water in the battery cooling water system, In a method of operating a fuel cell power generation system that enables consumption of a hot water tank shell for storing hot water that has been collected and that continues operation when the amount of hot water in the hot water tank is less than or equal to full, before starting the operation of the fuel cell The hot water in the hot water storage tank is guided to the battery cooling water system to heat the cooling water, thereby shortening the startup time of the fuel cell.

  Alternatively, before starting the operation of the fuel cell, the hot water in the hot water tank is led to the battery cooling water system and consumed for heating the cooling water, and the operation time of the fuel cell is extended in accordance with the consumed amount. Features.

  According to the fuel cell power generation system of the present invention, surplus hot water generated during power generation and stored in hot water is introduced into the battery cooling water system, and the temperature of the fuel cell before starting operation is increased. For this reason, excess hot water stored in the hot water storage tank is used before the start of operation, and the time until the hot water storage tank becomes full by subsequent power generation can be extended, improving the operating rate and increasing the high load operating time This is effective for improving power generation efficiency. Furthermore, since hot water is introduced into the battery cooling water system, there is an advantage that the temperature of the battery can be raised in a short time at startup.

  In the best mode of the present invention, hot water in a hot water tank is supplied to a cooling water tank provided in a cooling system of the battery using a head between the hot water tank and the cooling water tank, and is provided in the cooling system. The battery is supplied to the battery by a circulation pump for cooling the battery, and the fuel cell at the time of startup is heated. Furthermore, the excess of the hot water (hot water) whose temperature has dropped at the battery outlet is discharged out of the system, and the heat required is heated by the heat exchanger using the exhaust heat of the fuel processor (reformer). It is set as the structure which returns to a cooling water tank again, after heating by collect | recovering. Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a system diagram of a fuel cell power hot water supply system according to Embodiment 1 of the present invention. The fuel cell power hot water supply system includes a fuel processing device 1 that generates a hydrogen-rich anode gas 6, a fuel cell 9 in which oxygen in the anode gas 6 and air 29 generates DC power through an electrochemical reaction, and heat generated during power generation. It has a hot water storage tank 18 that is heated from the tap water to the hot water through the exchange system and stored.

  The fuel treatment apparatus 1 is supplied with city gas 2 and air 3 through the blowers 34 and 35 and deionized water 5 from the tap water 30 through the water treatment apparatus 23a. The fuel cell 9 includes an anode 9a, a cathode 9c, and a cooling cell 9b. The anode 9a is supplied with the anode gas 6 having an appropriate temperature through the heat exchanger 11-A and the drain trap 25. The cathode 9c is supplied with an air blower 36 for supplying the cathode air 8 and a humidifying cell 28 for humidifying the air 8. Air 29 is supplied. The cooling water 13 flows into the cooling cell 9b in operation through a battery cooling water system having the cooling water tank 10 and the cooling water pump 24 that take in the tap water 30. Heat generated during power generation in the fuel cell 9 is removed by the battery cooling water system, and the remainder is discharged to the outside as the cathode exhaust gas 15a and the anode exhaust gas 14.

  The heat recovery system takes in tap water 21 with the circulation pump 17 and passes through the three heat exchangers 11D, 11-B, 11-A to obtain heat, and becomes hot water 20 at a predetermined hot water supply temperature into the hot water storage tank 18. It is a system that can be stored. A heat exchanger 11 -C of a system different from this performs heat exchange between the cathode exhaust gas 15 a and the air 8.

  In the first heat exchanger 11-D, heat exchange is performed between the anode exhaust gas 14 exiting the battery anode 9a and the cathode exhaust gas 15b exiting the heat exchanger 11-C. In the heat exchanger 11-B, heat exchange with the battery cooling water 12 is performed. In the battery cooling water system, in order to cool the fuel cell 9, the cooling water 13 flows from the water storage tank (cooling water tank) 10 through the cooling cell 9 b by the pump 24 to cool the battery 9. The cooled cooling water 12 enters the heat exchanger 11 -B through the humidifying cell 28, gives the heat taken from the battery 9 to the low temperature side heat recovery system, and returns to the cooling water tank 10. The last heat exchanger 11-A performs heat exchange with the anode gas 6 at 100 degrees or more while being supplied from the fuel processing apparatus 1 to the fuel cell 9a. The heat recovery water that has exited the heat exchanger 11 -A becomes hot water 20 at a predetermined temperature, for example, 60 degrees, and is stored in the hot water storage tank 18.

  The hot water tank 18 is initially filled with cold water. When the operation is started, cold water is sent from the lower part of the tank 18 to the exhaust heat recovery system by the circulation pump 17 and returned to the upper part of the tank 18 as hot water, and hot water is supplied from the upper part of the hot water tank 18 toward the lower part. It has a structure that accumulates. When the hot water reaches the bottom, it is detected that it is full. When the user uses hot water, the hot water is led from the upper part of the hot water storage tank 18 to the hot water supply system 22. And the tap water 21 is supplied to the heat recovery system side from the lower part of the tank by the amount of hot water used. Therefore, in the DSS operation, the amount of hot water stored in the hot water storage tank when the operation is stopped on the day is determined from the amount of power generated by the battery and the amount of hot water used per day.

  Next, the starting method of the present embodiment will be described. At the time of start-up, the water in the cooling water tank 10 is below the battery operating temperature due to heat radiation during stoppage, and the battery 9 cannot be heated even if the pump 24 is operated and the cooling water is circulated in the battery.

  In the present embodiment, at the time of start-up, first, the water in the cooling water tank 10 and the cooling water system is discharged. Thereafter, the 60-degree hot water stored in the hot water storage tank 18 is passed through the hot water supply line 40 for activation connected to a hot water temperature portion in the upper part of the hot water storage tank, and the on-off valve 41 is opened to enter the cooling water tank 10. Supply. In this way, hot water is supplied using only the difference in height between the hot water storage tank 18 and the cooling water tank 10 without using a pump for driving.

  Further, in this embodiment, the hot water in the hot water tank is directly introduced into the battery cooling water system (cooling water tank), so the water temperature of the cooling water in the cooling water tank is reduced by a large amount of hot water sent to the cooling water tank. The temperature can be raised almost instantaneously to the temperature of the hot water tank. That is, the temperature rise of the water in the cooling tank is accelerated at each stage as compared with the indirect heat transfer method between the hot water in the hot water tank and the cold water in the cooling tank by the heat exchanger. Moreover, since the cooling water system is circulated using the hot water, as a result, the temperature of the battery can be increased in a shorter time than the heat exchange system.

  The hot water in the cooling water tank 10 is circulated by the cooling water pump 24, and heat is transmitted to the battery side through the cooling cell 9b to raise the temperature of the fuel cell 9. The temperature of the hot water at the battery outlet is lowered due to the temperature rise of the battery, but when sufficient hot water is stored in the hot water storage tank 18, the hot water is discharged from the system through the drain line 42 after leaving the humidification cell 28. In other words, by not returning the hot water at the battery outlet to the hot water tank, the hot water in the hot water tank is surely used before starting up, so that the battery operation rate can be improved as described later, and the high load with high power generation efficiency is high. Driving time can be increased. If the amount of hot water in the hot water storage tank 18 is limited in terms of calorific value, the hot water tank 18 can be circulated by compensating for the heat energy corresponding to the temperature drop and returning to the cooling water tank 10 without draining.

  The simplest method of supplying thermal energy is a method of supplying external energy. For example, an electric heater is provided in the cooling water tank 10. However, the use of external power is disadvantageous in terms of thermal efficiency. As a method of supplementing heat without using an electric heater, the fuel processing apparatus 1 is started, and the hot water after battery heating is exchanged with the exhaust gas having a high temperature discharged from the fuel processing apparatus 1 and then returned to the cooling water tank. It is also possible.

  FIG. 2 is a modified example of FIG. 1 and is a system diagram for warming the hot water after heating the battery by exchanging heat with the exhaust gas of the fuel processing apparatus. When the fuel processor 1 is started, city gas is supplied instead of the return anode gas 4 entering the fuel processor 1 and burns in the fuel processor 1. The high-temperature combustion gas is used to generate steam for reforming and to preheat fuel and air, and is discharged as exhaust gas 7. The exhaust gas 7 of 100 degrees or more is heat-exchanged with the heated hot water 12 discharged from the cooling cell 9b by the heat exchanger 11-E. The heated hot water 12 is returned to the cooling water tank through the supply pipe 44.

  In addition, at the time of starting, the water from the hot water storage tank 18 is not flowing because the circulating water pump 17 is stopped. Therefore, heat exchange by the heat exchanger 11-B in the battery cooling water system is not performed. In addition, it is desirable that the startup hot water supply line 40 is provided with a deionizer 23b for removing ions contained in tap water in order to prevent deterioration of the battery.

  Embodiment 2 of the present invention is a system in which the cooling water in the battery cooling water system is heated before the operation is started. FIG. 3 is a system diagram of a fuel cell power hot water supply system according to the second embodiment. Hot water from the hot water tank 18 is supplied to the heat exchanger 11-F provided in the battery cooling water system, and the cooling water 13 is heated.

  According to this, since the cooling water is indirectly heated, the tap water is not directly mixed in the cooling water tank 10, and the water treatment device 23a for producing the deionized water used in the first embodiment is not necessary. There are benefits.

  The hot waste water 42 at the outlet of the heat exchanger 11-F exchanges heat with the exhaust gas 7 of the fuel processing apparatus 1, and after being heated, returns to the inlet of the heat exchanger 11-F again, and heat is supplied to the cooling water side while circulating. It is also possible to continue to give.

  FIG. 4 shows the configuration of the cooling water tank according to the third embodiment. The cooling water tank of this embodiment is applicable to the cooling water tank 10 of FIGS. 1 to 3, and a piping for heat exchange, for example, a piping 45 with fins 46 is provided in the cooling water tank 10 to store hot water. The hot water supply line 40 for starting from the tank 18 is connected.

  In this fuel cell power generation and hot water supply system, hot water from the hot water storage tank 18 continues to flow into the pipe 45 only by a drop from the end of operation to the start of operation so that the temperature of the cooling water 13 in the cooling water tank 10 does not decrease due to heat dissipation. It is a thing. Thereby, at the time of starting, since the cooling water can be immediately flowed to the cooling cell 9b without raising the temperature of the cooling water 13 of the fuel cell 9, the starting time can be shortened.

  In addition, if it adds about Example 2 (FIG. 3), the effect of the same indirect heating will be acquired even if it replaces with the cooling water tank of this structure instead of providing heat exchanger 11-F. This eliminates the need for the heat exchanger 11-F and has an effect of simplifying the system.

  FIG. 5 is a block diagram of a fuel cell showing Embodiment 4 according to the present invention. Here, the periphery of the battery stack 9 is covered with a jacket 50 around a pipe 51 through which hot water flows, and the hot water supply line 40 for activation is connected to the pipe 51.

  In this fuel cell power generation and hot water supply system, hot water from the hot water storage tank 18 continues to flow through the pipe 51 from the end of operation to the start of operation so that the temperature of the battery stack 9 does not decrease due to heat dissipation, and the startup time is further shortened. Can be obtained.

  Note that such a jacket can also be applied to the cooling water tank 18 to prevent heat dissipation of the cooling water by keeping the tank warm. In addition to supplying hot water while the system is stopped, by passing hot water through the jacket 50 of the fuel cell 9 even during operation at a low load, a decrease in battery temperature due to heat radiation from the battery during low load operation can be prevented. As a result, stable operation is possible even with a low load, and the operation load range is further expanded.

  The embodiments of the present invention have been described above. In these embodiments, the use of hot water in the hot water tank can save the external energy required for temperature rise of the battery at the time of start-up, thereby reducing the start-up loss and, as a result, improving the power generation efficiency throughout the day.

  Next, improvement in power generation efficiency and system operation rate by using hot water in the hot water tank for system activation will be described.

  FIG. 6 shows the relative relationship between the amount of power used and the amount of power generated in the household fuel cell system, and the relationship between the amount of heat demand and the amount of heat recovered. In general, the power demand is the same as or higher than the battery power generation, and conversely, the heat demand is often less than the heat recovery. In particular, in summer, the heat demand is considerably less than the amount of heat recovered, and heat is left by that much. On the other hand, power demand may not be met by battery power generation alone, and system power is also required. Further, the relationship between the battery power generation amount and the heat recovery amount is almost directly proportional, and the ratio is about 0.7 to 0.9 with respect to the heat recovery amount 1.

  Thus, depending on the demand balance between heat and electric power, if the hot water storage tank becomes full during power generation, the battery cannot be cooled, so power generation cannot be continued, and operation must be stopped. For this reason, the operation rate of a system falls. Alternatively, when trying to increase the operating rate, it is impossible to maintain high-load operation that is advantageous from the viewpoint of power generation efficiency, and low-load operation is forced despite the power demand.

  In general, since the amount of hot water used in the morning is small at home, it is not necessary to store a large amount of hot water in a hot water tank at the time of startup. In this regard, according to the present invention described above, the excess hot water in the hot water tank is consumed for the temperature rise of the fuel cell after the operation is completed or before the operation is started. The operation time can be increased accordingly.

  Next, the advantages of consuming the amount of hot water in the hot water storage tank before the start-up as in the present invention will be described from the viewpoint of operation time and the ratio of daily high load operation.

  7 and 8 schematically show the relationship between the amount of hot water in the hot water storage layer and the operation time at the start of power generation. The upper left figure in FIG. 7 shows a case where the amount of hot water remaining in the hot water storage tank before the start of power generation is large. The operation time until the hot water tank became full was A time as shown in the lower left figure. The operation load of the battery during that time is X, and hot water is supplied twice.

  The right figure in FIG. 7 shows a case where the amount of hot water remaining in the hot water tank before the start of power generation is small (the present invention), the operating load of the battery is X as in the left figure, and hot water is also supplied twice at the same time. . However, the operation time until the hot water tank is full is longer than B time and the left figure. That is, if the power generation amount and the hot water supply load, which are the operation loads, are the same, the lower the level of the hot water storage tank at the start, the longer the operation can be continued. Therefore, according to the present invention, the operation availability is improved.

  In the case of FIG. 8, the amount of hot water in the hot water tank is the same as in FIG. 7, and the time when the hot water tank is full is the same. In other words, both the operating hours are the same as the A time, but when the amount of hot water in the hot water storage tank before the start of power generation is large (the left figure), the battery operating load is X until hot water is supplied twice, and the hot water supply The battery operating load is reduced to Y until the subsequent hot water tank is full. Here, the slope of the line in the upper diagram corresponds to the amount of heat recovered, and the relationship between the amount of heat recovered and the amount of power generation is almost directly proportional. On the other hand, when the amount of hot water remaining in the hot water tank is small (right figure), the inclination of the upper figure after hot water supply is larger in the right figure, and in order to fill the hot water tank in the same time as the left figure, Operation that increases the amount of heat recovery is required. As a result, the operating load in the right figure is Z, and a higher load operation is performed as compared with Y in the left figure.

  As described above, according to the present invention, high load operation can be performed with higher power generation efficiency than low load operation. Therefore, when operating the fuel cell power generation system, operation with high power generation efficiency is possible even during the same operation time. become.

1 is a system diagram showing a configuration of a fuel cell power hot water supply system according to Embodiment 1 of the present invention. FIG. FIG. 6 is a system diagram of a fuel cell power generation hot water system showing a modification of the first embodiment. FIG. 5 is a system diagram of a fuel cell power hot water supply system according to a second embodiment. The block diagram of the cooling water tank by Example 3. FIG. FIG. 6 is a configuration diagram of a fuel cell according to a fourth embodiment. Explanatory drawing of the relationship between the demand and supply of electric power and heat in a household fuel cell. Explanatory drawing of the relationship between the amount of hot water storage, and fuel cell operation time. Explanatory drawing of the relationship between hot water storage amount and a fuel cell driving | operation load.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel processing apparatus (reformer), 2 ... City gas, 4 ... Return anode gas, 5 ... Deionized water, 6 ... Anode gas, 7 ... Combustion exhaust gas, 8 ... Cathode air, 9 ... Fuel cell, 10 ... Cooling water tank, 11 ... Heat exchanger, 17 ... Circulation pump, 18 ... Hot water tank, 20 ... Hot water, 21 ... Tap water, 23 ... Deionizer, 24 ... Cooling water circulation pump, 40 ... Hot water, hot water tank, 42 ... Drain Line, 45 ... heat exchanger piping, 46 ... fins, 50 ... heat insulation jacket.

Claims (9)

Fuel cell, battery cooling water system that cools it, exhaust heat from battery exhaust gas and exhaust heat recovery system that recovers heat from the cooling water of battery cooling water system, and heat recovery In a fuel cell power generation system that has a hot water storage tank for storing hot water and continues operation when the amount of hot water in the hot water storage tank is less than full,
A fuel cell power generation system comprising a hot water supply pipe for guiding the hot water in the hot water storage tank to the battery cooling water system so that the startup time of the fuel cell can be shortened.   2. The fuel cell power generation system according to claim 1, wherein the hot water supply pipe is configured to supply hot water from the hot water storage tank to a cooling water tank of the battery cooling water system using a difference in height.   3. The heat exchanger according to claim 1 or 2, further comprising: a heat exchanger that heats the hot water used for raising the temperature of the fuel cell using exhaust heat discharged from a fuel processing device (reformer), and again fuels the fuel cell. A fuel cell power generation system configured to increase the temperature of a battery.   3. The drain line for discharging the cooling water of the battery cooling water system before starting, the hot water supply pipe for supplying hot water of the hot water storage tank to the cooling water tank of the battery cooling water system, and the cooling according to claim 1 or 2 A circulation pump for supplying hot water from the water tank to the fuel cell and a heat exchanger for exchanging heat between the hot water from the fuel cell outlet and the exhaust gas from the fuel processing device are provided, and the heated hot water is returned to the cooling water tank again. A fuel cell power generation system characterized by being returned.   3. The heat exchanger pipe according to claim 2, wherein hot water from the hot water storage tank is injected into the battery cooling water tank to indirectly retain the cooling water of the battery cooling water system. Fuel power generation system.   3. A jacket for supplying warm water around the fuel cell, a discharge line for discharging the warm water out of the system, and a pipe for supplying warm water from the hot water tank to the jacket of the fuel cell according to claim 1 or 2. A fuel cell power generation system. Fuel cell, battery cooling water system that cools it, exhaust heat from battery exhaust gas and exhaust heat recovery system that recovers heat from the cooling water of battery cooling water system, and heat recovery In the operation method of the fuel cell power generation system, which has a hot water storage tank for storing hot water, and continues to operate when the amount of hot water in the hot water storage tank is less than full,
Before starting the operation of the fuel cell, the operation of the fuel cell power generation system is characterized in that the hot water in the hot water storage tank is guided to the battery cooling water system to heat the cooling water, thereby shortening the startup time of the fuel cell. Method.   8. The fuel cell power generation system according to claim 7, wherein the fuel cell or the cooling water tank of the battery cooling water system is kept warm by using hot water in the hot water storage tank while the power generation of the fuel cell is stopped. how to drive. Hot water produced by heat recovery with a battery cooling water system that cools the fuel cell and an exhaust heat recovery system that recovers heat from the exhaust gas from the battery exhaust gas and heat from the cooling water in the battery cooling water system. In a method for operating a household fuel cell power generation system that allows consumption of hot water from a hot water storage tank that stores water and continues operation when the amount of hot water in the hot water storage tank is less than full,
Before starting the operation of the fuel cell, the hot water in the hot water storage tank is led to the battery cooling water system and consumed for heating the cooling water, and the operation time of the fuel cell is extended in accordance with the consumption. To operate the fuel cell power generation system.

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