JP5202854B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system.

  Fuel cell systems produce electrical energy by reacting hydrogen with oxygen. The fuel cell system is provided with a hydrogen generation unit that produces hydrogen as fuel by reacting a hydrocarbon-based raw material such as city gas with water. The hydrogen-rich gas generated here is supplied to the fuel cell. A method of generating electricity is common.

  In order to efficiently generate power in the fuel cell, it is necessary to keep the fuel cell main body at an optimum temperature, and thus cooling is necessary. In many cases, water is used as a cooling medium. However, a hot water storage tank is provided, and heat generated outside the fuel cell by the cooling water is used to convert the water in the hot water tank into hot water. It can be recovered. Thereby, the fuel cell system is constructed as a cogeneration system.

  FIG. 4 shows the configuration of such a conventional fuel cell system (see, for example, Patent Document 1 and FIG. 2).

  In FIG. 4, 101 is a fuel cell, 102 is a reformer, 103 is a combustion section, 104 is a hot water storage tank, 105 is a heat exchanger, 107 is a condenser, 108 is a water storage tank, 109 is a cooling water tank, and 110 is the reverse. Osmosis membrane device, 111 is a hot water supply channel, 112 is a hot water circulation channel, 113a and 113b are ion exchange resins, 115 is a cooling water circulation pump, 116 is a cooling water supply pump, 117 is a reforming water supply pump, 118 is A blower, 119 is a hot water circulating pump, 120 is a level sensor, 125 is a cooling water circulation passage, 126 is a drain valve for discharging hot water, and 130 is a control unit.

  In such a fuel cell system, a hot water storage circulation path 112 that circulates water in a hot water storage tank 104 in which the amount of water is maintained by supplying city water as tap water, and water collected by the condenser 107 are stored. By providing the reverse osmosis membrane device 110 and the bypass pipe 140 between the water storage tank 108, a part of the water circulating in the hot water circulation path 112 is used as cooling water for the fuel cell 101.

  The water flowing into the reverse osmosis membrane device 110 from the hot water storage tank 104 by the hot water circulation pump 119 includes high-purity water that has permeated through the reverse osmosis membrane and concentrated water in which impurities that could not permeate the reverse osmosis membrane are concentrated. The purified water is led to the bypass pipe 140 side, and the concentrated water is led to the heat exchanger 105 side provided downstream of the hot water circulation path 112.

  As a result, high-purity water is supplied to the cooling water tank 109 as cooling water for the fuel cell 101, while the concentrated water circulates in the hot water circulation passage 112 and circulates in the cooling water circulation passage 124 in the heat exchanger 105. Heat exchange with cooling water. By storing the concentrated water heat-exchanged with the cooling water in the cooling water circulation passage 124 in the hot water storage tank 104 as hot water storage, the thermal energy from the fuel cell 101 can be recovered. On the other hand, the hot water can be used for hot water supply or the like.

On the other hand, the cooling water whose temperature has decreased due to heat exchange circulates through the cooling water circulation passage 124 and returns to the cooling water tank 109 to be used again for cooling the fuel cell 101.
JP 2002-134126 A

  In the above conventional fuel cell system, water supply to the water storage tank 108 and the cooling water tank 109, which are water tanks related to the operation of the fuel cell, is provided between the reverse osmosis membrane device 110 and the water storage tank 108. This is done by opening an on-off valve (not shown). The on-off valve is opened when water in the water tank is insufficient.

  However, in the conventional fuel cell system, the branch point A between the hot water circulation channel 112 and the bypass pipe 140 is located upstream of the heat exchanger 105 in the hot water circulation channel 112. When performing, the water flowing from the hot water storage tank 104 branches into high-purity water toward the heat exchanger 105 and the bypass pipe 140. For this reason, the flow rate of the hot water flowing through the heat exchanger 105 varies from the value initially assumed from the output of the hot water circulation pump 119 (target flow rate value).

  Since the stability of the heat exchange rate of the heat exchanger 105 is based on the stability of the flow rate of water flowing through the cooling water circulation path 125 and the hot water circulation channel 112, the amount of hot water flowing through the heat exchanger 105 is the target flow rate value. , The heat exchange rate of the heat exchanger 105 also changes. Since the heat exchange rate of the heat exchanger 105 affects the temperature of the cooling water returning to the cooling water tank 109, when the heat exchange rate of the heat exchanger 105 becomes unstable, the temperature of the fuel cell 101 is set within a predetermined range. It was difficult to control within.

  The present invention has been made in view of such a problem, and when a hot water replenishment operation is performed on a water tank related to the operation of a fuel cell using hot water in a hot water circulation path, the heat exchanger is used as a heat exchanger. An object of the present invention is to provide a fuel cell system capable of stably controlling the amount of water flowing in and controlling the temperature of the fuel cell within a stable temperature range.

In order to achieve the above object, a first aspect of the present invention is a fuel cell system including a fuel cell ,
A heat medium flow path through which water for cooling the fuel cell flows;
A cooling water tank for storing water for cooling the fuel cell;
A hot water storage tank,
A hot water storage passage through which hot water stored in the hot water storage tank flows;
A hot water storage pump for flowing the hot water in the hot water flow path;
A heat exchanger for heat exchange between the hot water flowing through the hot-water flow passage with the water flowing through the heat medium flow path,
A recovered water tank to store water that will be recovered from the gas generated from the fuel cell system,
A cooling water supply pump for supplying water from the recovered water tank to the cooling water tank;
A hot water supply path for supplying hot water stored in the hot water that is branched and taken out from the hot water flow path on the downstream side of the heat exchanger to the hot water flow, to the recovered water tank;
It is a fuel cell system provided with the flow regulator which adjusts the amount of the hot water stored in the water supply channel.

Further, the second aspect of the present invention is a water level sensor for detecting a water level in the recovered water tank;
Wherein the water level detected by the water level sensor lowers, said savings hot water of the hot water storage water channel and a controller for controlling the flow regulator to supply the recovered water tank, the fuel of the first aspect of the present invention It is a battery system.

  Moreover, 3rd this invention is the 1st or 2nd in which the connection part of the said hot water storage water flow path and the said water supply path is installed in the position higher than the position of the downstream exit of the said heat exchanger. It is a fuel cell system of the present invention.

  Moreover, 4th this invention is provided in the position where at least one part of the said hot water storage flow path of the downstream of the said heat exchanger is lower than the connection part of the said hot water storage flow path and the said water supply path, The fuel cell system according to any one of the first to third aspects of the present invention.

The fifth of the present invention, the hot water storage water passage, the flow path cross-sectional area in the connecting section between the water supply path is greater than the flow path cross-sectional area of the upstream side the hot-water storage water passage of said connecting portion, It is a fuel cell system according to any one of the first to fourth aspects of the present invention.

Further, the present invention of the sixth, the hot water storage water passage, the flow path cross-sectional area in the connecting section between the water supply path is greater than the flow path cross-sectional area of the downstream side the hot-water storage water passage of said connecting portion, It is a fuel cell system according to any one of the first to fifth aspects of the present invention.

  The seventh aspect of the present invention is the fuel cell system according to any one of the first to fourth aspects of the present invention, wherein the amount of hot water flowing through the water supply channel by the flow rate regulator is equal to or less than the amount of hot water flowing through the hot water storage channel. It is.

The eighth aspect of the present invention is the fuel cell system according to the first aspect of the present invention, wherein the recovered water tank is a recovered water tank that stores water recovered from at least the exhaust gas from the fuel cell.

  According to the present invention, the amount of water flowing into the heat exchanger can be stably controlled, and the temperature of the fuel cell can be controlled within a stable temperature range.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention or an invention related to the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic diagram showing a configuration of a fuel cell system according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the fuel cell system according to the first embodiment is a fuel cell that generates electricity by reacting a gas rich in hydrogen and a gas containing oxygen (in this embodiment, air). Unit 1, a hot water storage tank 2 that collects heat generated from the fuel cell unit 1 and stores it as hot water, and a hydrogen-rich gas supplied to the fuel cell unit 1 is converted into hydrocarbon-based raw materials (in this embodiment, city gas And a hydrogen generation unit 3 that generates from water, a combustion unit 4 that heats the hydrogen generation unit 3 by burning a hydrogen-rich gas or a raw material that has not been used in the fuel cell unit 1, and a fuel cell unit 1 A heat exchanger 5 for exchanging heat generated during power generation to the hot water storage tank 2, a recovery water channel 60 through which water recovered from the gas generated from the fuel cell system flows, and a recovery connected to the recovery water channel 60 Water tank 6 and recovered water And a ion exchange resin 7 for increasing the purity of the water tank 6. A water level sensor 6a for monitoring the water level of the stored cooling water is provided inside the recovered water tank 6, and the water level sensor 6a is realized by, for example, a float switch. Further, an exhaust gas flow path discharged from the combustion section 4, an anode off gas flow path on the off gas discharge side of the hydrogen gas flow path 17 of the fuel cell section 1, and a cathode off gas flow path on the air discharge side of the fuel cell section 1. Condensers 61, 62, and 63 are respectively provided, and the water recovered from each off gas by each of the condensers 61 to 63 flows through the recovered water channel 60 and is stored in the recovered water tank 6.

  Furthermore, the fuel cell system according to the present embodiment includes a cooling water tank 8 that stores high-purity water supplied to the fuel cell system, and a hot water storage pump 9 that supplies water from the hot water storage tank 2 to the heat exchanger 5. A cooling water circulation pump 10 for circulating water in the cooling water tank 8 as cooling water for the fuel cell unit 1, a cooling water supply pump 11 for supplying water in the recovered water tank 6 to the cooling water tank 8, and cooling The water tank 8 and the cooling water valve 12 which prevents the water of the ion exchange resin 7 from flowing backward are provided.

  Furthermore, the fuel cell system according to the present embodiment includes a flow rate regulator 13 for supplying a part of the water supplied from the hot water storage tank 2 to the heat exchanger 5 by the hot water storage pump 9 to the recovered water tank 6, and a cooling water tank. 8 is a heat medium flow path 14 that is a path that circulates through the heat exchanger 5 by the cooling water circulation pump 10, and a hot water flow path 15 that is a path that circulates from the hot water storage tank 2 through the heat exchanger 5 by the hot water storage pump 9. And a water supply path 16 which is a path branched from the hot water storage water flow path 15 and supplied to the recovered water tank 6 by the flow rate regulator 13, and from the hydrogen generator 3 to the combustion section 4 via the fuel cell section 1. And a hydrogen gas passage 17 through which a hydrogen-rich gas flows, and a controller 18 that controls the operation of the flow rate regulator 13 based on the water level detected by the water level sensor 6a.

  At this time, the water supply path 16 is connected to the hot water flow path 15 at a branch point B on the downstream side of the position where the heat exchanger 5 is disposed with respect to the flow of the hot water indicated by an arrow in the figure. .

In the configuration described above, the fuel cell unit 1 corresponds to the fuel cell of the present invention, the hot water storage tank 2 corresponds to the hot water storage tank of the present invention, the hot water storage pump 9 corresponds to the hot water storage pump of the present invention, and the hot water storage channel. 15 corresponds to the hot water storage water passage of the present invention, and the heat exchanger 5 corresponds to the heat exchanger of the present invention. The recovered water tank 6 corresponds to the recovered water tank of the present invention, the water supply channel 16 corresponds to the water supply channel of the present invention, and the flow rate regulator 13 corresponds to the flow rate regulator of the present invention.

  The water level sensor 6a corresponds to the water level sensor of the present invention, and the controller 18 corresponds to the controller of the present invention.

  Hereinafter, the operation of the fuel cell system according to Embodiment 1 of the present invention configured as described above will be described.

  The basic operation of the fuel cell system is broadly divided into (1) an operation for generating a hydrogen-rich gas in the hydrogen generator 3 and (2) electricity and heat from the hydrogen-rich gas and air in the fuel cell unit 1. (3) an operation of recovering heat generated from the fuel cell unit 1 to the hot water storage tank 2, and (4) an operation of supplying water recovered from the fuel cell system and water supplied from the outside to each unit, It is divided into. This will be described below.

  In the operation of (1) above, the hydrogen generator 3 uses the reforming catalyst to reform from the steam obtained by heating the water supplied from the cooling water tank 8 and the raw material supplied from the outside. The reaction produces hydrogen rich gas. Since this reforming reaction is an endothermic reaction, the heat necessary for the reaction is given to the hydrogen generating unit 3 by burning the raw material or the hydrogen-rich gas in the burning unit 4. The hydrogen-rich gas produced in this way is supplied to the fuel cell unit 1 and used for the operation (2).

  In the operation (2), the fuel cell unit 1 reacts with air supplied from an air supply means such as a blower (not shown) and hydrogen-rich gas supplied from the hydrogen generation unit 3 to generate electricity. Generate heat. The hydrogen-rich gas that has not been used for power generation is sent to the combustion unit 4 through the hydrogen gas flow path 17, burned as fuel in the combustion unit 4, and used for heating the hydrogen generation unit 3. The heat generated in the fuel cell unit 1 is cooled by water flowing through the heat medium flow path 14 in order to control the temperature of the fuel cell unit 1 to a predetermined temperature.

  In the operation (3), the water flowing through the heat medium flow path 14 from the cooling water tank 8 by the cooling water circulation pump 10 recovers the heat generated in the fuel cell unit 1 as a heat medium. Part 1 is cooled. The recovered heat is transferred from the hot water storage tank 2 to the water flowing through the hot water storage channel 15 by the hot water storage pump 9 in the heat exchanger 5. As a result, the heat generated from the fuel cell unit 1 can be recovered in the hot water storage tank 2.

  The operation (4) is as follows. Although not shown in the figure, the water in the combustion exhaust gas generated from the combustion unit 4, the water in the cathode exhaust air discharged from the fuel cell unit 1, and the hydrogen-rich gas that was not used in the fuel cell unit 1 Water such as water is collected in the collected water tank 6 and stored. These waters are sent to the ion exchange resin 7 by the cooling water supply pump 11 to remove contained metal ions and the like to make high-purity water, and then stored in the cooling water tank 8. A cooling water valve 12 is provided to partition the water in the recovered water tank 6 and the water in the cooling water tank 8.

  In this way, the water stored in the cooling water tank 8 is supplied again to the fuel cell unit 1 and the hydrogen generation unit 3 and used to generate electricity and heat.

  When only the water collected from each part cannot sufficiently cover the water, the recovered water tank 6 is replenished by the flow rate regulator 13 from the water supply path 16 provided in the hot water storage water flow path 15.

  At this time, in the fuel cell system according to the present embodiment, the branch position of the water supply path 16 from the hot water flow path 15 is downstream from the position of the heat exchanger 5 with respect to the hot water flow indicated by the arrow in the figure. It is the structure connected at the branch point B on the side.

  Thereby, all the water led from the hot water storage tank 2 by the hot water storage pump 9 is introduced into the heat exchanger 5 and exchanges heat with water as a heat medium circulating in the heat medium flow path 14.

  After the heat exchange, a part of the water flowing out from the heat exchanger 5 branches to the water supply path 16, and the rest returns to the hot water storage tank 2.

  In this operation, a constant amount of water corresponding to the operation of the hot water storage pump 9 passes through the heat exchanger 5 and is not affected by the change in the amount of water to the water supply channel 16 by the flow rate regulator 13. Therefore, the heat exchange rate of the heat exchanger 5 is stabilized, and the temperature of the fuel cell unit 1 can be stabilized, that is, controlled within a predetermined range.

  Thereby, the fuel cell unit 1 can stably generate electric energy and heat energy.

  Next, the operation on the water supply channel 16 side will be further described.

  As described above, the water level sensor 6 a is installed in the recovered water tank 6, and when the water level falls below a predetermined value, the controller 18 that detects this supplies water to the recovered water tank 6. Therefore, the flow rate regulator 13 is controlled so that the water in the hot water storage channel 15 is sent to the recovered water tank 6 through the water supply channel 16. When the water level in the recovered water tank 6 becomes higher than a predetermined value by replenishing water, the controller 18 stops the supply of water by the flow rate regulator 13. In this way, control is performed so that water is always present in the recovered water tank 6.

  When a float switch is used as the water level sensor 6a, if the switch is turned on and energized at a position corresponding to the predetermined value in the recovered water tank 6, when the switch is turned on due to a drop in the water level, the controller 18 can detect the current from the float switch and start the flow regulator 13. On the other hand, if the water level in the recovered water tank 6 rises due to the water supply from the water supply channel 16 and the switch is turned off, the controller 18 detects that the current from the float switch stops flowing, and the flow regulator 13 Control to stop.

  During this time, on the side of the hot water flow path 15, since the water of a constant amount corresponding to the operation of the hot water storage pump 9 passes through the heat exchanger 5, the temperature of the fuel cell unit 1 is stabilized.

  The control of the cooling water tank 8 is detected by the water level sensor 8a based on the water level sensor 8a provided in the cooling water tank 8 in order to keep the water in the cooling water tank 8 above a predetermined water level. When the water level falls below a predetermined value, water is supplied from the recovered water tank 6 by the cooling water supply pump 11. At this time, the controller 18 controls the operation of the cooling water supply pump 11 based on the water level of the water level sensor 8a of the cooling water tank 8, but is supplied from the recovered water tank 6 to the cooling water tank 8. In order to compensate for the decreasing amount of water, the flow rate regulator 13 may be controlled together with the operation of the cooling water supply pump 11 to supply water to the recovered water tank 6 from the water supply path 16.

  The flow rate adjuster 13 is not limited to a specific configuration as long as it can adjust the flow rate of the water supply channel 16. It may be pumped by a pump or the like, may be an on-off valve such as an electromagnetic valve, or may be a flow rate adjusting valve such as a needle valve. In this embodiment, an electromagnetic valve is used.

  The amount of water supplied to the recovered water tank 6 via the water supply path 16 needs to be smaller than the amount of water sent from the hot water storage tank 2 to the heat exchanger 5 by the hot water storage pump 9. This is because the amount of water passing through the heat exchanger 5 is kept constant. In the present embodiment, the amount of water sent from the hot water storage tank 2 to the heat exchanger 5 is about 0.1 to 0.5 L / min. Therefore, the amount of water flowing through the water supply channel 16 is set to about 0.1 L / min. However, compared to the pressure loss of the upstream piping from the hot water storage channel 15 to the branch point B from the hot water storage tank 2 via the heat exchanger 5 to the water supply channel 16, the water supply channel 16 on the downstream side. If the pressure loss of the pipe from the branch point B to the hot water storage tank 2 is sufficiently small (in this embodiment, the pressure loss is 1/10 times or less), the flow rate regulator 13 returns to the recovered water tank 6. Since the water to be sent uses the water in the hot water storage tank 2 directly through the hot water storage channel 15 on the downstream side instead of the upstream side, the amount of water supplied by the flow rate regulator 13 is not limited to about 0.1 L / min.

  Further, in the present embodiment, as shown in FIG. 1, the water supply path 16 is positioned higher than the position of the outlet of the heat exchanger 5 positioned on the downstream side with respect to the flow of water in the hot water flow path 15. It is characterized in that it is provided.

  This is due to the following reason. That is, the water sent from the hot water storage tank 2 to the heat exchanger 5 is heated by heat exchange in the heat exchanger 5. Since the amount of gas that can be dissolved is reduced when water is heated, air such as oxygen that cannot be completely dissolved is generated as bubbles. When these bubbles accumulate in the heat exchanger 5, they become a factor that hinders heat transfer. Further, if bubbles accumulate in the piping of the hot water storage channel 15, the channel may be blocked. In addition, since the water seal in the pipe is broken, water cannot be sent at a stable flow rate.

  In order to remove this bubble, it can respond by attaching an air vent plug to the arbitrary locations of the hot water storage flow path 15 on the downstream side of the heat exchanger 5. However, if the air vent plug is attached, the number of parts increases, which increases the cost of the fuel cell system.

  Therefore, in the present embodiment, by adopting the above-described configuration, air generated in the water supply channel 16 is used to remove bubbles generated in the heat exchanger 5 without using an air vent plug. 15 can be removed. Air bubbles generated in the heat exchanger 5 are likely to be accumulated in the piping of the water supply passage 16 at a higher position, and the air bubbles are carried to the recovered water tank 6 along with the supply of water to the recovered water tank in the flow rate regulator 13. Go.

  In addition, the entire pipe of the water supply channel 16 is provided at a position higher than the outlet side of the heat exchanger 5, and only the connection portion of the pipe corresponding to the branch point B between the water supply channel 16 and the hot water storage water channel 15 is connected to the heat exchanger 5. You may make it provide in a position higher than the exit side. This also allows air bubbles to escape to the water supply channel 16 side and make it cheaper.

  Moreover, in order to make it easy to collect the bubble which generate | occur | produced in the hot water storage flow path 15 in the piping of the water supply path 16, it is not limited to the structure of the said FIG. 1, but as shown in FIG. You may make it make a part of piping of the hot water flow path 15 which becomes downstream with respect to the flow of water rather than the connection part of a corresponding piping lower than the said connection part. By doing so, the bubbles easily move to the water supply channel 16 due to the buoyancy of water, and the air bleeding performance can be improved.

  Furthermore, the chlorine contained in the tap water used in the hot water storage tank 2 by setting the position of the connecting portion of the pipe corresponding to the branch point B of the hot water flow passage 15 to the water supply passage 16 to the downstream side of the heat exchanger 5. There is an advantage that it is easy to remove by heating.

  This will be described below. The water heated by the heat exchanger 5 is supplied to the recovered water tank 6 by the flow rate regulator 13.

  The recovered water tank 6 has a structure communicating with the atmosphere in order to recover cathode air that has passed through the fuel cell unit 1 and water in the combustion exhaust gas generated from the combustion unit 4. Therefore, the water sent to the recovered water tank by the flow rate regulator 13 also falls to the same pressure as the atmosphere, so that the heated water is more likely to release chlorine.

  By reducing the chlorine of the water supplied to the recovered water tank 6 in this way, it is possible to reduce the load on the ion exchange resin 7 when the water of the recovered water tank 6 is supplied to the cooling water tank 8. Become. Thereby, the lifetime of the ion exchange resin 7 can be extended and durability performance can be improved.

  Further, in order to make it easier for air bubbles to collect in the water supply passage 16, the flow passage cross-sectional area of the connecting portion of the pipe corresponding to the branch point B between the water supply passage 16 and the hot water storage water flow passage 15 is set to be larger than the flow passage cross-sectional area before and after that. It is better to make it larger. By enlarging the cross-sectional area of the flow path and providing a space in which bubbles are collected wider than the front and rear pipes, the bubbles are more easily collected in the space. At this time, the flow path cross-sectional area of the connection portion may not be larger than the other portion of the flow path in both of the connection portions. It may be large only for the upstream side of the connecting portion, or may be large only for the downstream side.

  As described above, in the fuel cell system according to the present embodiment, water necessary for cooling the fuel cell unit 1 can be supplied without changing the amount of water flowing through the heat exchanger 5, and the hot water storage channel 15. It is possible to remove the bubbles in the inside, and the amount of water sent to the heat exchanger can be stably controlled, so that the temperature of the fuel cell unit 1 can be stably controlled, and power generation in the fuel cell unit 1 Can be performed stably. Therefore, it is possible to stably supply power energy and heat energy from the fuel cell system, and it is possible to realize a highly reliable fuel cell system.

  Furthermore, it is possible to extend the life of the ion exchange resin and improve the durability performance.

(Embodiment 2)
As described in the prior art, the water used in the fuel cell system can be recovered by condensing the water generated in the device and reused, or by supplying external water. It is funded.

  Similarly, in the first embodiment, the water to be supplied to the cooling water tank 8 is water in the combustion exhaust gas generated from the combustion unit 4 collected by condensation in the system, or the cathode discharged from the fuel cell unit 1. After collecting all the water in the exhausted air, the water in the hydrogen-rich gas that was not used in the fuel cell unit 1 and the water introduced from the hot water storage tank 2 through the water supply path 16 into the recovered water tank 6, It was supposed to be used after increasing the purity with the exchange resin 7.

  In contrast, in the fuel cell system according to the second embodiment, when water needs to be supplied to the cooling water tank 8, the water branched from the hot water storage channel 15 is directly supplied to the cooling water tank 8 from the water supply channel. This is different from the first embodiment.

  The second embodiment will be described below with reference to the drawings.

FIG. 3 is a schematic diagram showing a configuration of a fuel cell system according to Embodiment 2 of the invention related to the present invention.

  As shown in FIG. 3, in the present embodiment, the downstream side of the water supply channel 16 from the flow rate regulator 13 is not connected to the recovered water tank 6 as in the first embodiment, but directly from the flow rate regulator 13. The cooling water tank 8 is connected.

    In addition, an ion exchange resin 19 is further provided between the cooling water tank 8 and the flow rate regulator 13 to remove metal ions and the like of water passing therethrough so as to increase purity.

  As a result, when the water level detected by the water level sensor 8a of the cooling water tank 8 is lowered and water is supplied to the cooling water tank 8, water supply to the cooling water tank 8 can be performed only by controlling the flow rate regulator 13. It is not necessary to operate the cooling water supply pump 11 in order to supply water from the recovered water tank 6 to the cooling water tank 8 as in the first embodiment, and no extra operation and power are consumed. More efficient water supply operation is possible.

  Further, in the present embodiment, the cooling water tank 8 is disposed above the branch point B between the water supply channel 16 and the hot water storage channel 15, and the water supply channel 16 is connected to the cooling water tank 8 positioned above the branch point B. It is set as the structure which extends.

  Thereby, the following effects are acquired. That is, when it is configured to supply water to the recovered water tank 6 as in the first embodiment, the recovered water tank 6 needs to collect all the water recovered from the water supply channel 16 and the recovered water channel 60. It must be provided at the bottom of the fuel cell system. In this case, the water in the water supply channel 16 inevitably flows downward, and securing air bleedability becomes a problem.

  On the other hand, since the cooling water tank 8 has a degree of freedom in the arrangement inside the system by adopting a configuration in which the cooling water tank 8 is supplied as in the second embodiment, from the branch point B which is a position to supply water. Can also be installed upwards. In this case, the water in the water supply path 16 flows upward, and the air also moves upward along the water supply path 16 together with the flow of water, so that the water is finally easily discharged from the outlet of the water supply path 16. That is, the air release property of the water supply channel 16 can be improved.

  In the above embodiments, the flow rate regulator 13 on the water supply channel 16 is controlled by the controller 18 based on the water level detection of the water level sensor 6a or 8a. The water level sensors 6a and 8a may be omitted. In this case, you may perform ON-OFF control according to the operation time of a fuel cell system, ON-OFF control according to the electric power generation amount in a fuel cell, etc.

  The fuel cell system according to the present invention has an effect of stably controlling the amount of water flowing through the heat exchanger and controlling the temperature of the fuel cell within a predetermined range. For example, it is effective as a household fuel cell cogeneration system.

It is a schematic diagram which shows the structure of the fuel cell system which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the other structural example of the fuel cell system which concerns on Embodiment 1 of this invention. It is a schematic diagram which shows the structure of the fuel cell system which concerns on Embodiment 2 of the invention relevant to this invention. It is a schematic diagram which shows the structure of the fuel cell system which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell part 2 Hot water storage tank 3 Hydrogen production | generation part 4 Combustion part 5 Heat exchanger 6 Recovery water tank 6a Water level sensor 7 Ion exchange resin 8 Cooling water tank 8a Water level sensor 9 Hot water storage pump 10 Cooling water circulation pump 11 Cooling water supply pump 12 Cooling Water valve 13 Flow rate regulator 14 Heat medium flow path 15 Hot water flow path 16 Water supply path 16s Downstream path 17 Hydrogen gas flow path 18 Controller 19 Ion exchange resin 61, 62, 63 Condenser A Branch point B Branch point

Claims (8)

A fuel cell system comprising a fuel cell ,
A heat medium flow path through which water for cooling the fuel cell flows;
A cooling water tank for storing water for cooling the fuel cell;
A hot water storage tank,
A hot water storage passage through which hot water stored in the hot water storage tank flows;
A hot water storage pump for flowing the hot water in the hot water flow path;
A heat exchanger for heat exchange between the hot water flowing through the hot-water flow passage with the water flowing through the heat medium flow path,
A recovered water tank to store water that will be recovered from the gas generated from the fuel cell system,
A cooling water supply pump for supplying water from the recovered water tank to the cooling water tank;
A hot water supply path for supplying hot water stored in the hot water that is branched and taken out from the hot water flow path on the downstream side of the heat exchanger to the hot water flow, to the recovered water tank;
A fuel cell system comprising: a flow rate regulator for adjusting the amount of hot water stored in the water supply channel. A water level sensor for detecting the water level in the recovered water tank;
When the water level detected by the water level sensor is reduced, said savings hot water of the hot water storage water channel and a controller for controlling the flow regulator to supply the recovered water tank, the fuel according to claim 1 Battery system.   3. The fuel cell system according to claim 1, wherein at least a connection portion between the hot water storage channel and the water supply channel is installed at a position higher than a position of a downstream outlet of the heat exchanger.   The at least one part of the said hot water storage flow path in the downstream of the said heat exchanger is provided in the position lower than the connection part of the said hot water storage flow path and the said water supply path. Fuel cell system. Wherein the hot water storage water passage, the flow path cross-sectional area in the connecting section between the water supply path is greater than the flow path cross-sectional area of the upstream side the hot-water storage water passage of said connecting portion, to any one of claims 1 to 4 The fuel cell system described. Wherein the hot water storage water passage, the flow path cross-sectional area in the connecting section between the water supply path is greater than the flow path cross-sectional area of the downstream side the hot-water storage water passage of said connecting portion, to any one of claims 1 to 5 The fuel cell system described.   The fuel cell system according to any one of claims 1 to 4, wherein an amount of hot water flowing through the water supply channel by the flow rate regulator is set to be equal to or less than an amount of hot water flowing through the hot water channel. The recovered water tank is a recovery water tank to store the recovered water from the exhaust gas from at least the fuel cell, the fuel cell system according to claim 1.

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