JP2017162561A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system which enables the increase of the efficiency of collecting condensed water.SOLUTION: A fuel cell system 10 comprises: a reformer 21; a fuel cell 22; a condenser 30; a tank 40; a quality-modified water pipe 90; a water tank 111; an absorbent tank 112; and an ECU 130. The reformer 21 produces a fuel gas. The fuel cell 22 generates an electric power by the fuel gas and an oxidant gas. The condenser 30 cools the fuel gas to produce condensed water. The tank 40 stores the condensed water. The quality-modified water pipe 90 supplies the condensed water stored in the tank 40 to the reformer 21 as quality-modified water. The water tank 111 cools a water vapor-containing gas by heat exchange with the water vapor-containing gas. In the absorbent tank 112, an adsorbent which adsorbs, by an adsorption reaction, water stored in the water tank 111 is stored. The ECU 130 controls water adsorption by the absorbent and desorption thereof.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell system.

  When performing steam reforming in a fuel cell system, water is required. This water is called reformed water, and it is essential that the water does not contain ions. Therefore, city water is passed through an ion exchange resin for use. If condensed water that can be recovered by cooling the exhaust gas can be used as part or all of this reformed water, the influence of chlorine contained in city water and the precipitation of calcium / silica can be avoided. . Therefore, the load on the ion exchange resin can be reduced, and the life of the fuel cell system can be extended. As a fuel cell system that uses such condensed water of exhaust gas as reformed water, there is a fuel cell system described in Patent Document 1.

  The fuel cell system described in Patent Document 1 includes a reformer, a fuel cell, a condenser, a tank, a water level sensor, and a control unit. The reformer reforms the fuel material with reformed water to generate anode gas. The fuel cell generates power with anode gas and cathode gas. The condenser cools the water vapor-containing gas generated as the system is operated to generate condensed water. The tank collects the condensed water generated in the condenser and stores it as liquid phase reforming water. The water level sensor detects the water level in the tank. The control unit does not limit the power generation output of the fuel cell when the water level of the tank detected by the water level sensor is equal to or higher than a predetermined water level. On the other hand, the control unit limits or stops the power generation output of the fuel cell when the water level of the tank detected by the water level sensor is lower than a predetermined water level.

JP 2011-34701 A

  By the way, in the fuel cell system described in Patent Document 1, for example, when the outside air temperature becomes high, the heat exchange efficiency of the condenser is lowered, so that it is difficult to collect the condensed water. In such a situation, the water level of the tank is likely to be lower than the predetermined water level, so that the power generation output of the fuel cell is likely to be limited or stopped. When the power generation output of the fuel cell is limited or stopped, the electronic device using the power of the fuel cell cannot be driven, and there is a possibility that the function required for the system cannot be satisfied.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a fuel cell system capable of improving the recovery efficiency of condensed water.

  In order to solve the above problems, the fuel cell system (10) includes a reformer (21), a fuel cell (22), a condenser (30), a tank (40), and a reforming water pipe (90). ), A refrigerant storage unit (111), an adsorbent storage unit (112), and a control unit (130). The reformer reforms the fuel with the reforming water to generate fuel gas. The fuel cell generates power using fuel gas and oxidant gas. The condenser cools the steam-containing gas by performing heat exchange between the steam-containing gas and the first refrigerant, and generates condensed water. The tank stores the condensed water produced by the condenser. The reforming water pipe supplies condensed water stored in the tank as reforming water to the reformer. The refrigerant storage unit stores the second refrigerant and cools the water vapor-containing gas by exchanging heat with the water vapor-containing gas. The adsorbent storage unit stores an adsorbent that adsorbs the second refrigerant stored in the refrigerant storage unit by an adsorption reaction. The control unit controls adsorption and desorption of the second refrigerant by the adsorbent.

  According to this configuration, the second refrigerant stored in the refrigerant storage unit evaporates due to the adsorption reaction of the adsorbent in the adsorbent storage unit. Since the refrigerant storage unit is cooled by the latent heat of evaporation of the second refrigerant generated at that time, heat exchange is performed between the cooled refrigerant storage unit and the water vapor-containing gas, so that the condensed water is generated from the water vapor-containing gas. Generated. In addition, the controller can repeatedly perform adsorption and desorption of the adsorbent, thereby continuously cooling the water vapor-containing gas using the latent heat of vaporization of the second refrigerant. As a result, compared with the case where the steam-containing gas is cooled only by the condenser, the recovery efficiency of the condensed water can be increased.

  In addition, the code | symbol in the bracket | parenthesis as described in the said means and a claim is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

  According to the present invention, the condensate recovery efficiency can be improved.

It is a block diagram which shows schematic structure of the fuel cell system of 1st Embodiment. It is a figure which shows typically the structure of the condenser and water tank of 1st Embodiment. It is a figure which shows typically the structure of the adsorbent tank of 1st Embodiment. It is a flowchart which shows the procedure of the process performed by ECU of 1st Embodiment. It is a time chart which shows each transition of the outside water temperature in the fuel cell system of a 1st embodiment, the amount of condensed water recovery, and the difference water amount of the amount of recovered water of condensed water, and the amount of supply water. It is a block diagram which shows schematic structure of the fuel cell system of 2nd Embodiment. It is a flowchart which shows the procedure of the process performed by ECU of 2nd Embodiment.

<First Embodiment>
Hereinafter, a first embodiment of the fuel cell system will be described.
As shown in FIG. 1, the fuel cell system 10 of this embodiment includes a power generation module 20, a condenser 30, a tank 40, a pump 50, an ion exchange resin 60, and a supply system 70. . The power generation module 20, the condenser 30, the tank 40, the pump 50, and the ion exchange resin 60 are accommodated in the housing 80.

  The power generation module 20 includes a reformer 21, a fuel cell 22, and a combustion unit 23. The power generation module 20 has a structure in which the reformer 21, the fuel cell 22, and the combustion unit 23 are modularized.

  The reformer 21 includes an evaporation unit 210 and a reforming unit 211. The evaporation unit 210 steams the liquid phase reforming water supplied from the tank 40 through the reforming water pipe 90. Hydrocarbon fuel is supplied to the reforming unit 211 from the outside of the housing 80 through the fuel pipe 91. The reforming unit 211 generates fuel gas by steam reforming the fuel with the steam generated by the evaporation unit 210. The fuel gas is hydrogen or a hydrogen-containing gas. The fuel gas generated by the reforming unit 211 is supplied to the fuel cell 22 through the fuel pipe 92.

  The fuel cell 22 includes an electrolyte layer 220, an anode layer 221, and a cathode layer 222. Fuel gas is supplied to the anode layer 221 from the reformer 21 through the fuel pipe 92. An oxidant gas is supplied to the cathode layer 222 from the outside of the housing 80 through the oxidant pipe 93. The oxidant gas is, for example, air. More specifically, oxygen in the air is used as the oxidant gas. In the fuel cell 22, power is generated by a chemical reaction between the fuel gas supplied to the anode layer 221 and the oxidant gas supplied to the cathode layer 222 via the electrolyte layer 220. Through this chemical reaction, the anode off gas is discharged from the anode layer 221 and the cathode off gas is discharged from the cathode layer 222. The anode off gas contains unreacted hydrogen. The cathode off gas contains unreacted oxygen. The anode off-gas discharged from the anode layer 221 and the cathode off-gas discharged from the cathode layer 222 flow into the combustion unit 23 through the off-gas pipes 94a and 94b.

  The combustion unit 23 burns the anode off gas flowing out from the fuel cell 22 with the cathode off gas. The combustion flame generated by the combustion of the combustion unit 23 is used for heating the reforming unit 211. Thereby, the temperature of the reforming unit 211 is maintained at the reforming reaction temperature. The combustion exhaust gas generated by the combustion flows into the condenser 30 through the combustion exhaust gas pipe 95. In the present embodiment, this combustion exhaust gas corresponds to a steam-containing gas.

  The condenser 30 radiates and cools the combustion exhaust gas by exchanging heat between the combustion exhaust gas flowing out of the combustion unit 23 and the cooling water supplied from the supply system 70. That is, in the present embodiment, water is used as the first refrigerant supplied from the supply system 70 to the condenser 30. Specifically, as shown in FIG. 2, the condenser 30 includes a core portion 31 and header tanks 32 and 33.

  The core portion 31 includes an exhaust gas circulation region 310 through which combustion exhaust gas flows and a cooling water circulation region 311 through which cooling water flows. Specifically, the core portion 31 has a laminated structure in which a plurality of tubes (not shown) are laminated. The longitudinal direction of the tube is the direction indicated by the arrow Y in the figure. Hereinafter, the direction indicated by the arrow Y is referred to as “tube longitudinal direction”. In the exhaust gas circulation region 310 of the core portion 31, the combustion exhaust gas flows along the tube longitudinal direction Y. Cooling water flows along the tube longitudinal direction Y in the cooling water circulation region 311 of the core portion 31. The exhaust gas circulation region 310 and the cooling water circulation region 311 are partitioned by a partition wall of a tube (not shown).

  The header tanks 32 and 33 are provided at both end portions of the core portion 31 in the tube longitudinal direction Y, respectively. The header tanks 32 and 33 are made of a cylindrical member.

  A partition wall 320 is provided inside one header tank 32. The partition 320 partitions the internal space of the header tank 32 into a distribution area 321 and a collection area 322. The distribution region 321 is connected to the combustion exhaust gas pipe 95 and one end of the exhaust gas circulation region 310 of the core portion 31. The collecting region 322 is connected to the cooling water pipe 100 and one end of the cooling water circulation region 311 of the core portion 31.

  A partition wall 330 is provided inside the other header tank 33. The partition wall 330 divides the internal space of the header tank 33 into a collection area 331 and a distribution area 332. The gathering region 331 is connected to the other end portion of the exhaust gas circulation region 310 of the core portion 31 and the exhaust pipe 96. The distribution area 332 is connected to the other end of the cooling water circulation area 311 of the core portion 31 and the cooling water pipe 102.

  In the condenser 30, the combustion exhaust gas flows into the distribution region 321 of the header tank 32 through the combustion exhaust gas pipe 95. The combustion exhaust gas flowing into the distribution area 321 is distributed to each tube of the exhaust gas circulation area 310 of the core portion 31. On the other hand, cooling water flows into the distribution region 332 of the header tank 33 through the cooling water pipe 102. The cooling water that has flowed into the distribution area 332 is distributed to each tube of the cooling water circulation area 311 of the core portion 31. The combustion exhaust gas is cooled by heat exchange between the combustion exhaust gas flowing through the exhaust gas circulation region 310 of the core portion 31 and the cooling water flowing through the cooling water circulation region 311. Thereby, the gas-phase water contained in the combustion exhaust gas is condensed, and condensed water is generated. Hereinafter, the combustion exhaust gas from which moisture in the vapor phase is removed as condensed water is also simply referred to as “exhaust gas”. Condensed water and exhaust gas generated in the exhaust gas circulation region 310 of the core part 31 are collected in the collecting region 331 of the header tank 33. Condensed water and exhaust gas collected in the collecting region 331 of the header tank 33 are discharged to the discharge pipe 96. The cooling water flowing through the cooling water circulation area 311 of the core portion 31 is collected in the collecting area 322 of the header tank 32. The cooling water collected in the collecting area 322 of the header tank 32 is discharged to the cooling water pipe 100.

  Condensed water and exhaust gas flow into the tank 40 through the discharge pipe 96 from the condenser 30. The tank 40 has a function of separating condensed water and exhaust gas flowing from the discharge pipe 96 and a function of storing condensed water. The exhaust gas separated in the tank 40 is discharged outside the housing 80 through the exhaust gas pipe 97. The condensed water stored in the tank 40 can be supplied as reforming water to the reformer 21 through the reforming water pipe 90 as shown in FIG.

  The pump 50 is provided in the reforming water pipe 90. The pump 50 is driven based on the supply of electric power, and pumps the condensed water stored in the tank 40 to the reformer 21 as reformed water.

  A city water supply pipe 98 is connected to the reformed water pipe 90 on the downstream side of the pump 50. In the fuel cell system 10 of this embodiment, for example, when the condensed water that can be supplied from the tank 40 to the reformer 21 is insufficient, it becomes difficult to maintain the power generation output of the fuel cell 22 with only the condensed water. In addition, the city water is supplied from the city water supply pipe 98 to the reformer 21, whereby the power generation operation of the fuel cell 22 can be maintained.

  The ion exchange resin 60 is disposed downstream of the connection point with the city water supply pipe 98 in the reformed water pipe 90. The ion exchange resin 60 selectively passes ions contained in the condensed water supplied from the tank 40 to the reformer 21 or city water supplied from the city water supply pipe 98 to the reformer 21. Purify them. Thereby, the purified water purified through the ion exchange resin 60 is supplied to the reformer 21.

  The supply system 70 supplies cooling water to the condenser 30. The supply system 70 includes a hot water tank 71, a pump 72, a radiator 73, and a blower 74.

  The hot water storage tank 71 is connected to the condenser 30 via the cooling water pipe 100. The hot water storage tank 71 is a part that stores cooling water discharged from the condenser 30 through the cooling water pipe 100. The cooling water stored in the hot water storage tank 71 is cooled with the passage of time by exchanging heat with the outside air. The cooling water stored in the hot water storage tank 71 is supplied to the radiator 73 via the cooling water pipe 101.

  The pump 72 is provided in the middle of the cooling water pipe 101. The pump 72 is driven based on the supply of electric power to pump the cooling water stored in the hot water storage tank 71 to the radiator 73.

  The radiator 73 radiates and cools the cooling water by exchanging heat between the cooling water supplied from the hot water tank 71 and the air flowing outside. The cooling water cooled in the radiator 73 is supplied to the condenser 30 through the cooling water pipe 102.

  The blower 74 blows air to the radiator 73. Thereby, the heat dissipation performance of the radiator 73 is improved.

  The fuel cell system 10 of the present embodiment has an auxiliary cooling mechanism 110 for improving the performance of generating condensed water in the condenser 30. The auxiliary cooling mechanism 110 includes a water tank 111, an adsorbent tank 112, and a valve 113.

  As shown in FIG. 2, the water tank 111 is provided in contact with the header tank 33 of the condenser 30. More specifically, the water tank 111 is disposed corresponding to a portion corresponding to the collecting region 331 in the header tank 33, that is, a portion through which combustion exhaust gas flows. Water as a refrigerant is stored in the water tank 111. In the present embodiment, the water tank 111 corresponds to the refrigerant storage unit. Moreover, the water stored in the water tank 111 corresponds to the second refrigerant. As shown in FIG. 1, the water tank 111 is connected to the adsorbent tank 112 via a pipe 114.

  The adsorbent tank 112 is provided in the cooling water pipe 100. More specifically, as shown in FIG. 3, the adsorbent tank 112 is disposed so as to surround the outer periphery of the cooling water pipe 100. Inside the adsorbent tank 112, a granular adsorbent capable of adsorbing water vapor by an adsorption reaction is stored. For example, silica gel or zeolite can be used as the adsorbent. In the present embodiment, the adsorbent tank 112 corresponds to an adsorbent storage unit.

  The valve 113 is provided in the pipe 114. The valve 113 is composed of, for example, an electromagnetic valve. The valve 113 opens and closes the pipe 114 by the opening and closing operation.

  In the auxiliary cooling mechanism 110, when the cooling water is stored in the water tank 111, when the valve 113 is opened, the adsorbent in the adsorbent tank 112 adsorbs water vapor, so that the water in the water tank 111 is Evaporate. The water tank 111 is cooled by the latent heat of evaporation of water generated at this time. By cooling the water tank 111, the condenser 30 that contacts the water tank 111 is also cooled. Thereby, since the combustion exhaust gas which flows through the gathering area | region 331 of the header tank 33 can be cooled more, the production amount of condensed water can be increased. Hereinafter, such an operation of the auxiliary cooling mechanism 110 is also referred to as an “adsorption operation”.

  On the other hand, when the adsorbent in the adsorbent tank 112 has absorbed water, when the temperature of the adsorbent rises, a so-called desorption action occurs in which water vapor is discharged from the adsorbent. In the present embodiment, as a method of increasing the temperature of the adsorbent, a method of increasing the temperature of the cooling water flowing through the cooling water pipe 100 and increasing the temperature of the adsorbent by heat transmitted from the cooling water pipe 100 to the adsorbent tank 112. Is adopted. The water vapor discharged by the desorption of the adsorbent flows into the water tank 111 through the pipe 114. At this time, the temperature of the water tank 111 is lower than the temperature of the adsorbent tank 112. Therefore, the water vapor flowing into the water tank 111 is cooled and condensed in the water tank 111. That is, the water once adsorbed by the adsorbent in the adsorbent tank 112 can be returned to the water tank 111. Thereby, the cooling function of the auxiliary cooling mechanism 110 can be regenerated. Hereinafter, such an operation of the auxiliary cooling mechanism 110 is also referred to as a “desorption operation”.

Next, the electrical configuration of the fuel cell system 10 will be described.
The fuel cell system 10 includes a water level sensor 120, a temperature sensor 121, and an ECU (Electronic Control Unit) 130. In the present embodiment, the ECU 130 corresponds to a control unit.

  The water level sensor 120 detects the water level Hw of the condensed water stored in the tank 40 and outputs a signal corresponding to the detected water level Hw of the condensed water to the ECU 130.

  The temperature sensor 121 detects the temperature Tw of the cooling water flowing through the cooling water pipe 102, in other words, the temperature Tw of the cooling water supplied from the radiator 73 to the condenser 30, and detects the detected temperature Tw of the cooling water. A corresponding signal is output to ECU 130.

  The ECU 130 controls the supply system 70. For example, the ECU 130 controls the pump 72 so that the cooling water having the reference flow rate FRb is supplied to the condenser 30. The reference flow rate FRb is set to, for example, “3 [L / min]”. Further, the ECU 130 acquires information on the temperature Tw of the cooling water supplied to the condenser 30 based on the output signal of the temperature sensor 121. The ECU 130 adjusts the rotation speed of the blower 74 so that the acquired cooling water temperature Tw becomes the target temperature.

  The ECU 130 controls the auxiliary cooling mechanism 110. Specifically, the ECU 130 acquires information on the water level Hw of the condensed water in the tank 40 detected by the water level sensor 120. The ECU 130 determines whether to perform the adsorption operation or the desorption operation in the auxiliary cooling mechanism 110 based on the acquired water level Hw of the condensed water in the tank 40.

  Next, with reference to FIG. 4, the control of the auxiliary cooling mechanism 110 by the ECU 130 will be specifically described. ECU 130 repeatedly executes the process shown in FIG. 4 at a predetermined calculation cycle.

  As shown in FIG. 4, the ECU 130 first determines whether or not the water level of the condensed water in the tank 40 is equal to or lower than the lower limit water level threshold value Hth1 as step S10. The lower limit water level threshold value Hth1 is set in advance by experiments or the like so that it can be determined whether or not the water level of the condensed water in the tank 40 has decreased to such an extent that the power generation output of the fuel cell 22 cannot be maintained. The lower limit water level threshold value Hth1 may be a value that can be changed by the ECU 130 in accordance with the operating state of the fuel cell system 10.

  When the water level of the condensed water in the tank 40 is equal to or lower than the lower limit water level threshold Hth1, that is, when the condensed water in the tank 40 is insufficient, the ECU 130 makes an affirmative determination in step S10 and performs adsorption control as step S11. Run. Specifically, ECU 130 opens valve 113. Thereby, when water is stored in the water tank 111, the condenser 30 is cooled by the above-described adsorption operation being performed by the auxiliary cooling mechanism 110, and the amount of condensed water generated in the condenser 30. Can be increased.

  If a negative determination is made in step S10, ECU 130 determines in step S12 whether the water level of the condensed water in tank 40 is equal to or higher than upper limit water level threshold Hth2. The upper limit water level threshold Hth2 is set in advance through experiments or the like so that it can be determined whether or not the water level is sufficient to maintain the power generation output of the fuel cell 22. The upper limit water level threshold Hth2 may be a value that can be changed by the ECU 130 in accordance with the operating state of the fuel cell system 10.

  When the water level of the condensed water in the tank 40 is equal to or higher than the upper limit water level threshold Hth2, that is, when there is sufficient condensed water in the tank 40, the ECU 130 makes an affirmative determination in step S12 and performs desorption control as step S13. I do. Specifically, the ECU 130 opens the valve 113 and sets the flow rate of the pump 72 to a predetermined flow rate FR1 that is smaller than the reference flow rate FRb. The predetermined flow rate FR1 is set to “0.5 [L / min]”, for example.

  Here, when the flow rate of the pump 72 is set to the predetermined flow rate FR1, the flow rate of the cooling water flowing into the condenser 30 is decreased, so that the temperature of the cooling water discharged from the condenser 30 to the cooling water pipe 100 is increased. To do. In this case, the temperature of the cooling water rises from, for example, “47 [° C.]” to “75 [° C.]”. The increased cooling water heat is transmitted to the adsorbent in the adsorbent tank 112, so that the temperature of the adsorbent is changed to a temperature at which desorption easily occurs. Therefore, the adsorption operation described above is performed by the auxiliary cooling mechanism 110, and the water once adsorbed by the adsorbent is returned to the water tank 111. That is, the auxiliary cooling mechanism 110 can be regenerated.

  If the ECU 130 makes a negative determination in step S12, it closes the valve 113 as step S14. Thereby, the auxiliary cooling mechanism 110 enters a state in which neither the adsorption operation nor the desorption operation is performed.

  Next, an operation example of the fuel cell system 10 of the present embodiment will be described with reference to FIG. In FIG. 5, the transition of the outside air temperature is a circle, the transition of the condensed water recovery amount in the tank 40 is a square, and the transition of the differential water amount between the condensed water recovery amount and the supply water amount is indicated by a triangle. The recovered water amount of the condensed water indicates the flow rate of the condensed water supplied from the condenser 30 to the tank 40. The amount of condensed water supplied indicates the flow rate of condensed water supplied from the tank 40 to the reformer 21.

  As shown in FIG. 5, if sufficient condensed water is present in the tank 40 during the period from time t10 to time t11, the ECU 130 performs desorption control. By executing the desorption control, the valve 113 is opened, and the auxiliary cooling mechanism 110 performs the desorption operation. Thereby, when water is adsorbed by the adsorbent in the adsorbent tank 112, the adsorbent is desorbed and water is returned to the water tank 111.

  After the time t11, when the outside air temperature rises, the amount of condensed water recovered in the condenser 30 decreases. As a result, the difference water amount between the recovered water amount of the condensed water and the supplied water amount decreases, so the water level of the condensed water in the tank 40 decreases.

  When the water level of the condensed water in the tank 40 becomes equal to or lower than the lower limit water level threshold Hth1 at time t12, the ECU 130 performs adsorption control. By performing the adsorption control, the valve 113 is opened, and the auxiliary cooling mechanism 110 performs the adsorption operation. Thereby, the amount of recovered water in the condenser 30 increases, and the amount of difference between the amount of recovered water and the amount of supplied water increases. Therefore, the water level of the condensed water in the tank 40 rises. Therefore, during the period from time t12 to time t13, by performing the adsorption operation by the auxiliary cooling mechanism 110, the difference water amount between the recovered water amount of the condensed water and the supplied water amount becomes “0 [cc / min]” or less. Can be avoided. As a result, it is possible to avoid a situation where the condensed water in the tank 40 is insufficient, so that the power generation operation of the fuel cell 22 using the condensed water can be continued for a longer period.

  According to the fuel cell system 10 of the present embodiment described above, the operations and effects shown in the following (1) to (5) can be obtained.

  (1) The auxiliary cooling mechanism 110 repeatedly performs the adsorption operation and the desorption operation based on the water level of the condensed water in the tank 40, whereby the water tank 111 is continuously cooled using the latent heat of vaporization of water. As a result, compared with the case where the steam-containing gas is cooled only by the condenser 30, the recovery efficiency of the condensed water can be increased. Thereby, it becomes possible to maintain the power generation output of the fuel cell 22 while suppressing the supply of city water to the reformer 21. If the power generation output of the fuel cell 22 can be maintained, for example, it is not necessary to purchase insufficient power from the power system, so that the energy cost can be reduced. Furthermore, since the condensed water recovery efficiency is increased, the condensed water can be easily used as the reformed water, so that the burden on the ion exchange resin 60 can be reduced. Therefore, the lifetime of the ion exchange resin 60 can be extended and the maintenance cost of the ion exchange resin 60 can be reduced.

  (2) The water tank 111 is provided in the condenser 30. Thereby, since the water tank 111 can be arrange | positioned using the dead space of the condenser 30, installation of the water tank 111 becomes easy.

  (3) The adsorbent tank 112 is provided in the cooling water pipe 100 through which the cooling water discharged from the condenser 30 flows. As a result, heat is transferred from the cooling water flowing through the cooling water pipe 100 to the adsorbent in the adsorbent tank 112, whereby the adsorbent can be heated. Therefore, since a separate heating device for heating the adsorbent is not necessary, the number of parts can be reduced.

  (4) The ECU 130 performs adsorption control for causing the adsorbent in the adsorbent tank 112 to adsorb water when the water level of the condensed water in the tank 40 is equal to or lower than the lower limit water level threshold Hth1. Thereby, the water in the water tank 111 is adsorbed by the adsorbent, so that the water tank 111 is cooled by the latent heat of evaporation of the water. By performing heat exchange between the cooled water tank 111 and the condenser 30, the condenser 30 is cooled, so that the amount of condensed water generated can be increased. As a result, since the amount of condensate stored in the tank 40 can be increased, it is easy to avoid a situation where the condensate used for power generation of the fuel cell 22 is insufficient. Therefore, it becomes easy to maintain the operation as the fuel cell system 10.

  (5) The ECU 130 performs desorption control for causing the adsorbent in the adsorbent tank 112 to desorb water when the water level of the condensed water in the tank 40 is equal to or higher than the upper limit water level threshold Hth2. As a result, water can be returned into the water tank 111 due to desorption of the adsorbent water, so that when the water level of the condensed water in the tank 40 subsequently decreases, the auxiliary cooling mechanism 110 immediately performs the adsorption operation. Therefore, it is easy to avoid a situation where the condensed water in the tank 40 is insufficient.

Second Embodiment
Next, a second embodiment of the fuel cell system 10 will be described. Hereinafter, the difference from the first embodiment will be mainly described.

  As shown in FIG. 6, the fuel cell system 10 further includes an outside air temperature sensor 122. The outside air temperature sensor 122 detects the outside air temperature Ta and outputs a signal corresponding to the detected outside air temperature Ta to the ECU 130.

  As shown in FIG. 7, in step S10, the ECU 130 according to the present embodiment determines whether or not the level of the condensed water in the tank 40 is equal to or lower than the lower limit water level threshold Hth1, and the outside air temperature Ta is a predetermined upper limit temperature threshold Tth1. It is determined whether it is above. The upper limit temperature threshold Tth1 is set in advance by experiments or the like so that it can be determined whether or not the outside air temperature has risen to such an extent that the condensed water in the tank 40 is expected to be insufficient. The upper limit temperature threshold value Tth1 may be a value that can be changed by the ECU 130 in accordance with the operating state of the fuel cell system 10.

  The ECU 130 makes an affirmative determination in step S10 when the water level of the condensed water in the tank 40 is equal to or lower than the lower limit water level threshold value Hth1, or when the outside air temperature Ta is equal to or higher than the predetermined upper limit temperature threshold value Tth1, and the adsorption in step S11. Take control.

  If the ECU 130 makes a negative determination in step S10, as step S12, whether or not the water level of the condensed water in the tank 40 is equal to or higher than the upper limit water level threshold Hth2, and whether or not the outside air temperature Ta is equal to or lower than the lower limit temperature threshold Tth2. Determine whether. The lower limit temperature threshold value Tth2 is set in advance by experiments or the like so that it can be determined whether or not the outside air temperature has decreased to such an extent that sufficient condensed water can be secured in the tank 40. The lower limit temperature threshold Tth2 may be a value that can be changed by the ECU 130 in accordance with the operating state of the fuel cell system 10.

  When the water level of the condensed water in the tank 40 is equal to or higher than the upper limit water level threshold Hth2, or when the outside air temperature Ta is equal to or lower than the lower limit temperature threshold Tth2, the ECU 130 makes an affirmative determination in step S12 and performs desorption control as step S13. Do.

  According to the fuel cell system 10 of the present embodiment described above, the operations and effects shown in the following (6) and (7) can be further obtained.

  (6) When the outside air temperature Ta is equal to or higher than the upper limit temperature threshold Tth1, the ECU 130 performs adsorption control for causing the adsorbent to cool water. Thereby, when the outside air temperature rises to such an extent that the condensed water in the tank 40 is expected to be insufficient, the auxiliary cooling mechanism 110 performs the adsorption operation, so that the amount of condensed water generated can be increased. As a result, since the amount of condensate stored in the tank 40 can be increased, it is easy to avoid a situation where the condensate used for power generation of the fuel cell 22 is insufficient. Therefore, it becomes easy to maintain the operation as the fuel cell system 10.

  (7) When the outside air temperature Ta is equal to or lower than the lower limit temperature threshold Tth2, the ECU 130 performs desorption control for causing the adsorbent to desorb water. As a result, when the outside air temperature is lowered to such an extent that sufficient condensed water can be secured in the tank 40, the auxiliary cooling mechanism 110 performs the desorption operation, so that the water is returned into the water tank 111. Can do. Accordingly, when the water level of the condensed water in the tank 40 is subsequently lowered, the auxiliary cooling mechanism 110 can immediately perform the adsorption operation, so that it is easy to avoid a situation where the condensed water in the tank 40 is insufficient. Become.

<Other embodiments>
In addition, each embodiment can also be implemented with the following forms.
The heating of the adsorbent tank 112 may be performed using a dedicated heating device.

  The water tank 111 may be disposed in the tank 40 or the exhaust gas pipe 97, for example. The position of the water tank 111 can be changed as appropriate as long as the position can cool the combustion exhaust gas.

  -Supply system 70 may use refrigerants other than water. Similarly, the auxiliary cooling mechanism 110 may use a refrigerant other than water.

  The condenser 30 is not limited to the one that generates condensed water by cooling the combustion exhaust gas, but may be one that generates condensed water by cooling a water vapor-containing gas such as anode gas, anode off gas, or cathode off gas.

  The means and / or function provided by the ECU 130 can be provided by software stored in a substantial storage device and a computer that executes the software, only software, only hardware, or a combination thereof. For example, when the ECU 130 is provided by an electronic circuit that is hardware, it can be provided by a digital circuit including a large number of logic circuits or an analog circuit.

  -This invention is not limited to said specific example. That is, the above-described specific examples that are appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the elements included in each of the specific examples described above and their arrangement, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, and can be changed as appropriate. Moreover, each element with which embodiment mentioned above is provided can be combined as long as it is technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the features of the present invention.

10: Fuel cell system 21: Reformer 22: Fuel cell 30: Condenser 40: Tank 90: Reformed water pipe 100: Cooling water pipe 111: Refrigerant reservoir (water tank)
112: Adsorbent storage (adsorbent tank)
130: ECU (control unit)

Claims (7)

A reformer (21) for reforming fuel with reformed water to generate fuel gas;
A fuel cell (22) for generating electricity with the fuel gas and oxidant gas;
A condenser (30) for cooling the steam-containing gas by exchanging heat between the steam-containing gas and the first refrigerant, and generating condensed water;
A tank (40) for storing the condensed water produced by the condenser;
A reforming water pipe (90) for supplying the condensed water stored in the tank as the reforming water to the reformer;
A refrigerant storage unit (111) for storing the second refrigerant and cooling the water vapor-containing gas by exchanging heat with the water vapor-containing gas;
An adsorbent storage unit (112) for storing an adsorbent that adsorbs the second refrigerant stored in the refrigerant storage unit by an adsorption reaction;
A controller (130) for controlling adsorption and desorption of the second refrigerant by the adsorbent;
A fuel cell system comprising: The fuel cell system according to claim 1, wherein the refrigerant storage unit is provided in the condenser. The fuel cell system according to claim 1 or 2, wherein the adsorbent storage unit is provided in a pipe (100) through which the first refrigerant discharged from the condenser flows. The said control part performs adsorption | suction control for making the said adsorbent adsorb | suck the said 2nd refrigerant | coolant, when the water level of the said condensed water in the said tank is below a minimum water level threshold value. The fuel cell system according to any one of the above. The controller performs desorption control for causing the adsorbent to desorb the second refrigerant when the water level of the condensed water in the tank is equal to or higher than an upper limit water level threshold. The fuel cell system as described in any one of -4. The said control part performs adsorption | suction control for making the said adsorbent adsorb | suck the said 2nd refrigerant | coolant, when outside temperature is more than an upper limit temperature threshold value. Fuel cell system. The controller performs desorption control for causing the adsorbent to desorb the second refrigerant when the outside air temperature is equal to or lower than a lower limit temperature threshold value. The fuel cell system described in 1.

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