JP6971605B2

JP6971605B2 - Fuel cell system

Info

Publication number: JP6971605B2
Application number: JP2017067587A
Authority: JP
Inventors: 壮哉白木; 幸司山本; 潤岩見; 沙奈細川; 修一井上
Original assignee: Osaka Gas Co Ltd
Current assignee: Osaka Gas Co Ltd
Priority date: 2017-03-30
Filing date: 2017-03-30
Publication date: 2021-11-24
Anticipated expiration: 2037-03-30
Also published as: JP2018170194A

Description

本発明は、燃料ガス及び酸素ガスを反応させて発電する燃料電池と、前記燃料電池から排出された排ガスから生じる凝縮水を回収する水タンクと、を備えた燃料電池システムに関する。 The present invention relates to a fuel cell system including a fuel cell that generates power by reacting a fuel gas and an oxygen gas, and a water tank that recovers condensed water generated from exhaust gas discharged from the fuel cell.

一般に、この種の燃料電池システムでは、燃料電池の発電に関連し、燃料電池を冷却するための冷却水や、水蒸気改質用の改質水が必要となり、この冷却水や改質水として、燃料電池からの排ガスから生じた凝縮水を貯留した水タンク中の水が用いられている。そして、水タンク中の凝縮水の水位が下限値以下になると燃料電池による発電が行えなくなり、水タンク中に水が補給されるまで、燃料電池システムの運転が停止することになる。これに対し、例えば特開２０１６−１７７９９８号公報には、水タンク中の凝縮水の水位が所定値以下に減少したとき、水タンク中の凝縮水の水位が正常レベルに戻るまで、燃料電池の出力を低減させた運転を行うようにして、水タンク中の凝縮水の減少により燃料電池システムの運転が停止することがないようにすることが提案されている。 Generally, in this type of fuel cell system, cooling water for cooling the fuel cell and reformed water for steam reforming are required in relation to the power generation of the fuel cell, and the cooling water and the reformed water are used as the cooling water and the reformed water. The water in the water tank that stores the condensed water generated from the exhaust gas from the fuel cell is used. When the water level of the condensed water in the water tank becomes equal to or lower than the lower limit, the fuel cell cannot generate electricity, and the operation of the fuel cell system is stopped until the water is replenished in the water tank. On the other hand, for example, Japanese Patent Application Laid-Open No. 2016-177998 states that when the water level of the condensed water in the water tank decreases below a predetermined value, the fuel cell is operated until the water level of the condensed water in the water tank returns to the normal level. It has been proposed to operate with reduced output so that the operation of the fuel cell system does not stop due to the reduction of condensed water in the water tank.

特開２０１６−１７７９９８号公報Japanese Unexamined Patent Publication No. 2016-177998

かかる上記従来の燃料電池システムによれば、水タンク中の凝縮水の減少により燃料電池システムの運転が停止することを抑制できるが、燃料電池の出力を低減させることで運転効率が低下するという問題がある。 According to the above-mentioned conventional fuel cell system, it is possible to suppress the operation of the fuel cell system from being stopped due to a decrease in the condensed water in the water tank, but there is a problem that the operation efficiency is lowered by reducing the output of the fuel cell. There is.

そこで、燃料電池の出力を低減させることなく水タンク中の凝縮水の水位を維持できる燃料電池システムが望まれる。 Therefore, a fuel cell system capable of maintaining the water level of condensed water in the water tank without reducing the output of the fuel cell is desired.

本発明に係る燃料電池システムは、
原燃料を水蒸気改質して燃料ガスを生成する改質器を備え、前記燃料ガス及び酸素ガスを反応させて発電する燃料電池と、
発電反応に用いられた燃料ガス中に残存する燃料成分を燃焼させて排ガスを生じさせる燃焼部と、
前記燃焼部から排出される前記排ガスの熱を回収する熱交換器と、
前記熱交換器による熱回収により前記排ガスから生じる凝縮水を回収する水タンクと、
前記水タンクに貯留された凝縮水を前記改質器に供給可能な水供給路と、
湯水を貯える貯湯タンクと、
前記排ガスから生じる凝縮水の量に関連する凝縮水情報として、前記貯湯タンクから供給されて前記熱交換器に流入する湯水の温度である流入湯水温度と前記水タンクに貯えられる水の量である貯水量とを取得する凝縮水情報取得部と、
前記排ガスから生じる凝縮水の量を調節可能な凝縮水発生量調節部と、
前記凝縮水情報が、凝縮水の量が減少傾向にあることを示す所定の凝縮水減少条件を満たすときである、前記流入湯水温度が設定温度まで上昇し、且つ、前記貯水量が設定下限水位まで減少したとき、前記凝縮水情報が所定の凝縮水増加条件を満たす、前記凝縮水発生量調節部に前記熱交換器へ冷却液を供給させる凝縮水増加処理を行わせた時間が所定時間に達するか、又は、前記貯水量が増加して目標水量になるまで、前記凝縮水発生量調節部に前記排ガス中から単位時間当たりに回収できる凝縮水の量を増加させる前記凝縮水増加処理を行わせる運転制御部と、を備え、
前記貯湯タンクと前記熱交換器との間で湯水を循環させる循環路を備え、前記凝縮水発生量調節部として、前記熱交換器に前記貯湯タンク中の湯水よりも低温の冷却液を供給可能な冷却液供給部を備え、前記運転制御部は、前記熱交換器を、前記排ガスと前記湯水との熱交換を行う湯水利用状態と、前記排ガスと前記冷却液との熱交換が可能な冷却液利用状態とに切替可能であり、前記凝縮水増加処理として、前記熱交換器を前記冷却液利用状態とし、前記冷却液供給部に前記熱交換器へ冷却液を供給させる。 The fuel cell system according to the present invention is
A fuel cell equipped with a reformer that steam reforms raw fuel to generate fuel gas and reacts the fuel gas and oxygen gas to generate power.
A combustion part that burns the fuel components remaining in the fuel gas used for the power generation reaction to generate exhaust gas,
A heat exchanger that recovers the heat of the exhaust gas discharged from the combustion unit, and
A water tank that recovers condensed water generated from the exhaust gas by heat recovery by the heat exchanger, and
A water supply path capable of supplying the condensed water stored in the water tank to the reformer, and
A hot water storage tank for storing hot water and
The condensed water information related to the amount of condensed water generated from the exhaust gas is the inflow hot water temperature, which is the temperature of the hot water supplied from the hot water storage tank and flowing into the heat exchanger, and the amount of water stored in the water tank. Condensed water information acquisition department to acquire the amount of stored water,
A condensed water generation amount adjusting unit that can adjust the amount of condensed water generated from the exhaust gas,
When the condensate water information satisfies a predetermined condensate water decrease condition indicating that the amount of condensate water tends to decrease, the inflow hot water temperature rises to the set temperature, and the water storage amount is the set lower limit water level. When the amount of condensed water information decreases to the specified time, the time required for the condensed water generation amount adjusting unit to perform the condensed water increasing treatment of supplying the cooling liquid to the heat exchanger is set to the predetermined time. The condensed water increasing treatment for increasing the amount of condensed water that can be recovered from the exhaust gas per unit time is performed on the condensed water generation amount adjusting unit until the amount of stored water reaches or the amount of stored water increases to reach the target amount of water. comprising a driving control unit, the to,
A circulation path for circulating hot water between the hot water storage tank and the heat exchanger is provided, and as the condensed water generation amount adjusting unit, the heat exchanger can be supplied with a coolant having a temperature lower than that of the hot water in the hot water storage tank. The operation control unit is provided with a cooling liquid supply unit, and the operation control unit cools the heat exchanger so that it can exchange heat between the exhaust gas and the hot water and the hot water utilization state and heat exchange between the exhaust gas and the coolant. It is possible to switch to the liquid utilization state, and as the condensed water increasing treatment, the heat exchanger is set to the coolant utilization state, and the coolant supply unit is made to supply the coolant to the heat exchanger.

この構成によれば、凝縮水の量が減少傾向にあるときに凝縮水発生量調節部により凝縮水増加処理を行わせるため、燃料電池の出力を低減させることなく水タンク中の凝縮水の水位を維持できる。 According to this configuration, when the amount of condensed water is decreasing, the condensed water generation amount adjusting unit performs the condensed water increase processing, so that the water level of the condensed water in the water tank is not reduced without reducing the output of the fuel cell. Can be maintained.

また、この構成によれば、水タンクの貯水量に応じて凝縮水減少条件が満たされているかを判定するので、凝縮水の量が減少傾向にあることを確度高く判定できる。Further, according to this configuration, it is determined whether the condition for reducing the condensed water is satisfied according to the amount of water stored in the water tank, so that it can be determined with high accuracy that the amount of condensed water is decreasing.

また、この構成によれば、凝縮水増加処理を行った時間に基づき凝縮水増加条件が満たされたと判定するので、過度に凝縮水増加処理を行うことを抑制できる。Further, according to this configuration, since it is determined that the condensed water increasing condition is satisfied based on the time when the condensed water increasing treatment is performed, it is possible to suppress the excessive condensed water increasing treatment.

また、この構成によれば、貯水量に基づき凝縮水増加条件が満たされたと判定するので、確度高く必要な貯水量を確保できる。
また、この構成によれば、凝縮水増加処理として冷却液供給部に熱交換器へ冷却液を供給させるので、熱交換器における熱回収の量が高められ、排ガスからの凝縮水の発生量を増加させることができる。これにより、燃料電池の出力を低減させることなく水タンク中の凝縮水の水位を維持することが可能になる。
本発明に係る燃料電池システムは、
原燃料を水蒸気改質して燃料ガスを生成する改質器を備え、前記燃料ガス及び酸素ガスを反応させて発電する燃料電池と、
発電反応に用いられた燃料ガス中に残存する燃料成分を燃焼させて排ガスを生じさせる燃焼部と、
前記燃焼部から排出される前記排ガスの熱を回収する熱交換器と、
前記熱交換器による熱回収により前記排ガスから生じる凝縮水を回収する水タンクと、
前記水タンクに貯留された凝縮水を前記改質器に供給可能な水供給路と、
湯水を貯える貯湯タンクと、
前記排ガスから生じる凝縮水の量に関連する凝縮水情報として、前記貯湯タンクから供給されて前記熱交換器に流入する湯水の温度である流入湯水温度と前記水タンクに貯えられる水の量である貯水量とを取得する凝縮水情報取得部と、
前記排ガスから生じる凝縮水の量を調節可能な凝縮水発生量調節部と、
前記凝縮水情報が、凝縮水の量が減少傾向にあることを示す所定の凝縮水減少条件を満たすときである、前記流入湯水温度が設定温度まで上昇し、且つ、前記貯水量が設定下限水位まで減少したとき、前記凝縮水情報が所定の凝縮水増加条件を満たす、前記凝縮水発生量調節部に前記熱交換器へ冷却液を供給させる凝縮水増加処理を行わせた時間が所定時間に達するか、又は、前記貯水量が増加して目標水量になるまで、前記凝縮水発生量調節部に前記排ガス中から単位時間当たりに回収できる凝縮水の量を増加させる前記凝縮水増加処理を行わせる運転制御部と、を備え、
前記燃料電池から前記熱交換器に前記排ガスを供給する排ガス配管を備え、前記凝縮水発生量調節部として、前記排ガス配管を冷却して前記排ガス配管を介した前記排ガスからの放熱状態を調節可能な冷却器を備え、前記運転制御部は、前記凝縮水増加処理として前記冷却器を動作させる。
この構成によれば、凝縮水の量が減少傾向にあるときに凝縮水発生量調節部により凝縮水増加処理を行わせるため、燃料電池の出力を低減させることなく水タンク中の凝縮水の水位を維持できる。
また、この構成によれば、水タンクの貯水量に応じて凝縮水減少条件が満たされているかを判定するので、凝縮水の量が減少傾向にあることを確度高く判定できる。
また、この構成によれば、凝縮水増加処理を行った時間に基づき凝縮水増加条件が満たされたと判定するので、過度に凝縮水増加処理を行うことを抑制できる。
また、この構成によれば、貯水量に基づき凝縮水増加条件が満たされたと判定するので、確度高く必要な貯水量を確保できる。
また、この構成によれば、凝縮水増加処理として排ガス配管を介して排ガスを冷却するので、排ガスからの凝縮水の発生量を増加させることができる。これにより、燃料電池の出力を低減させることなく水タンク中の凝縮水の水位を維持することが可能になる。
本発明に係る燃料電池システムは、
原燃料を水蒸気改質して燃料ガスを生成する改質器を備え、前記燃料ガス及び酸素ガスを反応させて発電する燃料電池と、
発電反応に用いられた燃料ガス中に残存する燃料成分を燃焼させて排ガスを生じさせる燃焼部と、
前記燃焼部から排出される前記排ガスの熱を回収する熱交換器と、
前記熱交換器による熱回収により前記排ガスから生じる凝縮水を回収する水タンクと、
前記水タンクに貯留された凝縮水を前記改質器に供給可能な水供給路と、
湯水を貯える貯湯タンクと、
前記排ガスから生じる凝縮水の量に関連する凝縮水情報として、前記貯湯タンクから供給されて前記熱交換器に流入する湯水の温度である流入湯水温度と前記水タンクに貯えられる水の量である貯水量とを取得する凝縮水情報取得部と、
前記排ガスから生じる凝縮水の量を調節可能な凝縮水発生量調節部と、
前記凝縮水情報が、凝縮水の量が減少傾向にあることを示す所定の凝縮水減少条件を満たすときである、前記流入湯水温度が設定温度まで上昇し、且つ、前記貯水量が設定下限水位まで減少したとき、前記凝縮水情報が所定の凝縮水増加条件を満たす、前記凝縮水発生量調節部に前記熱交換器へ冷却液を供給させる凝縮水増加処理を行わせた時間が所定時間に達するか、又は、前記貯水量が増加して目標水量になるまで、前記凝縮水発生量調節部に前記排ガス中から単位時間当たりに回収できる凝縮水の量を増加させる前記凝縮水増加処理を行わせる運転制御部と、を備え、
前記貯湯タンクと前記熱交換器との間で湯水を循環させる循環路を備え、前記熱交換器は、前記排ガスと前記湯水とを熱交換可能であり、前記凝縮水発生量調節部として、前記熱交換器の上流側において、前記循環路を流れる湯水を放熱させる放熱器を備え、前記運転制御部は、前記凝縮水情報が前記凝縮水減少条件を満たしていないときは、前記熱交換器に流入する湯水の温度が所定温度を超えているときに前記放熱器を所定の運転量で動作させ、前記凝縮水情報が前記凝縮水減少条件を満たしているときは、前記凝縮水増加処理として、前記放熱器を前記所定の運転量を超える運転量で動作させる。
この構成によれば、凝縮水の量が減少傾向にあるときに凝縮水発生量調節部により凝縮水増加処理を行わせるため、燃料電池の出力を低減させることなく水タンク中の凝縮水の水位を維持できる。
また、この構成によれば、水タンクの貯水量に応じて凝縮水減少条件が満たされているかを判定するので、凝縮水の量が減少傾向にあることを確度高く判定できる。
また、この構成によれば、凝縮水増加処理を行った時間に基づき凝縮水増加条件が満たされたと判定するので、過度に凝縮水増加処理を行うことを抑制できる。
また、この構成によれば、貯水量に基づき凝縮水増加条件が満たされたと判定するので、確度高く必要な貯水量を確保できる。
また、この構成によれば、凝縮水増加処理として放熱器を動作させて熱交換器に供給される湯水の温度を低下させる。その結果、熱交換器における熱回収の量が高められ、排ガスからの凝縮水の発生量を増加させることができる。これにより、燃料電池の出力を低減させることなく水タンク中の凝縮水の水位を維持することが可能になる。 Further, according to this configuration, since it is determined that the condition for increasing the condensed water is satisfied based on the amount of stored water, it is possible to secure the required amount of stored water with high accuracy.
Further, according to this configuration, since the cooling liquid is supplied to the heat exchanger by the coolant supply unit as the condensed water increasing treatment, the amount of heat recovery in the heat exchanger is increased, and the amount of condensed water generated from the exhaust gas is increased. Can be increased. This makes it possible to maintain the water level of the condensed water in the water tank without reducing the output of the fuel cell.
The fuel cell system according to the present invention is
A fuel cell equipped with a reformer that steam reforms raw fuel to generate fuel gas and reacts the fuel gas and oxygen gas to generate power.
A combustion part that burns the fuel components remaining in the fuel gas used for the power generation reaction to generate exhaust gas,
A heat exchanger that recovers the heat of the exhaust gas discharged from the combustion unit, and
A water tank that recovers condensed water generated from the exhaust gas by heat recovery by the heat exchanger, and
A water supply path capable of supplying the condensed water stored in the water tank to the reformer, and
A hot water storage tank for storing hot water and
The condensed water information related to the amount of condensed water generated from the exhaust gas is the inflow hot water temperature, which is the temperature of the hot water supplied from the hot water storage tank and flowing into the heat exchanger, and the amount of water stored in the water tank. Condensed water information acquisition department to acquire the amount of stored water,
A condensed water generation amount adjusting unit that can adjust the amount of condensed water generated from the exhaust gas,
When the condensate water information satisfies a predetermined condensate water decrease condition indicating that the amount of condensate water tends to decrease, the inflow hot water temperature rises to the set temperature, and the water storage amount is the set lower limit water level. When the amount of condensed water information decreases to the specified time, the time required for the condensed water generation amount adjusting unit to perform the condensed water increasing treatment of supplying the cooling liquid to the heat exchanger is set to the predetermined time. The condensed water increasing treatment for increasing the amount of condensed water that can be recovered from the exhaust gas per unit time is performed on the condensed water generation amount adjusting unit until the amount of stored water reaches or the amount of stored water increases to reach the target amount of water. Equipped with an operation control unit
An exhaust gas pipe that supplies the exhaust gas from the fuel cell to the heat exchanger is provided, and the exhaust gas pipe can be cooled to adjust the heat radiation state from the exhaust gas via the exhaust gas pipe as the condensed water generation amount adjusting unit. The operation control unit operates the cooler as the condensed water increasing process.
According to this configuration, when the amount of condensed water is decreasing, the condensed water generation amount adjusting unit performs the condensed water increase processing, so that the water level of the condensed water in the water tank is not reduced without reducing the output of the fuel cell. Can be maintained.
Further, according to this configuration, it is determined whether the condition for reducing the condensed water is satisfied according to the amount of water stored in the water tank, so that it can be determined with high accuracy that the amount of condensed water is decreasing.
Further, according to this configuration, since it is determined that the condensed water increasing condition is satisfied based on the time when the condensed water increasing treatment is performed, it is possible to suppress the excessive condensed water increasing treatment.
Further, according to this configuration, since it is determined that the condition for increasing the condensed water is satisfied based on the amount of stored water, it is possible to secure the required amount of stored water with high accuracy.
Further, according to this configuration, since the exhaust gas is cooled through the exhaust gas pipe as the treatment for increasing the condensed water, the amount of condensed water generated from the exhaust gas can be increased. This makes it possible to maintain the water level of the condensed water in the water tank without reducing the output of the fuel cell.
The fuel cell system according to the present invention is
A fuel cell equipped with a reformer that steam reforms raw fuel to generate fuel gas and reacts the fuel gas and oxygen gas to generate power.
A combustion part that burns the fuel components remaining in the fuel gas used for the power generation reaction to generate exhaust gas,
A heat exchanger that recovers the heat of the exhaust gas discharged from the combustion unit, and
A water tank that recovers condensed water generated from the exhaust gas by heat recovery by the heat exchanger, and
A water supply path capable of supplying the condensed water stored in the water tank to the reformer, and
A hot water storage tank for storing hot water and
The condensed water information related to the amount of condensed water generated from the exhaust gas is the inflow hot water temperature, which is the temperature of the hot water supplied from the hot water storage tank and flowing into the heat exchanger, and the amount of water stored in the water tank. Condensed water information acquisition department to acquire the amount of stored water,
A condensed water generation amount adjusting unit that can adjust the amount of condensed water generated from the exhaust gas,
When the condensate water information satisfies a predetermined condensate water decrease condition indicating that the amount of condensate water tends to decrease, the inflow hot water temperature rises to the set temperature, and the water storage amount is the set lower limit water level. When the amount of condensed water information decreases to the specified time, the time required for the condensed water generation amount adjusting unit to perform the condensed water increasing treatment of supplying the cooling liquid to the heat exchanger is set to the predetermined time. The condensed water increasing treatment for increasing the amount of condensed water that can be recovered from the exhaust gas per unit time is performed on the condensed water generation amount adjusting unit until the amount of stored water reaches or the amount of stored water increases to reach the target amount of water. Equipped with an operation control unit
A circulation path for circulating hot water between the hot water storage tank and the heat exchanger is provided, and the heat exchanger can exchange heat between the exhaust gas and the hot water, and the condensate water generation amount adjusting unit is described as the heat exchanger. On the upstream side of the heat exchanger, a radiator for radiating hot water flowing through the circulation path is provided, and the operation control unit uses the heat exchanger when the condensed water information does not satisfy the condensed water reduction condition. When the temperature of the inflowing hot water exceeds a predetermined temperature, the radiator is operated at a predetermined operating amount, and when the condensed water information satisfies the condensed water decreasing condition, the condensed water increasing treatment is performed. The radiator is operated at an operating amount exceeding the predetermined operating amount.
According to this configuration, when the amount of condensed water is decreasing, the condensed water generation amount adjusting unit performs the condensed water increase processing, so that the water level of the condensed water in the water tank is not reduced without reducing the output of the fuel cell. Can be maintained.
Further, according to this configuration, it is determined whether the condition for reducing the condensed water is satisfied according to the amount of water stored in the water tank, so that it can be determined with high accuracy that the amount of condensed water is decreasing.
Further, according to this configuration, since it is determined that the condensed water increasing condition is satisfied based on the time when the condensed water increasing treatment is performed, it is possible to suppress the excessive condensed water increasing treatment.
Further, according to this configuration, since it is determined that the condition for increasing the condensed water is satisfied based on the amount of stored water, it is possible to secure the required amount of stored water with high accuracy.
Further, according to this configuration, the radiator is operated as a process for increasing the condensed water to lower the temperature of the hot water supplied to the heat exchanger. As a result, the amount of heat recovery in the heat exchanger is increased, and the amount of condensed water generated from the exhaust gas can be increased. This makes it possible to maintain the water level of the condensed water in the water tank without reducing the output of the fuel cell.

以下、本発明に係る燃料電池システムの好適な態様について説明する。但し、以下に記載する好適な態様例によって、本発明の範囲が限定される訳ではない。Hereinafter, preferred embodiments of the fuel cell system according to the present invention will be described. However, the scope of the present invention is not limited by the preferred embodiments described below.

１つの態様として、前記貯湯タンクと前記熱交換器との間で湯水を循環させる循環路を備え、前記熱交換器は、前記排ガスと前記湯水とを熱交換可能であると好適である。 In one aspect, the hot water storage tank and provided with a circulation path for circulating the hot water between the heat exchanger, the heat exchanger, and the hot water and the exhaust gas is preferable to be possible heat exchange.

凝縮水は排ガスの冷却に伴い発生するので、排ガスからの凝縮水の発生量は熱交換器による排ガスからの熱回収量に依存する。そして、熱交換器が排ガスと湯水とを熱交換可能にする場合、熱交換器により排ガスから回収される熱の量は、貯湯タンクから供給されて熱交換器に流入する湯水の温度である流入湯水温度に依存し、流入湯水温度が高いほど排ガスから回収される熱の量が小さくなる。したがって、排ガスからの凝縮水の発生量は流入湯水温度に依存する。 Since condensed water is generated as the exhaust gas cools, the amount of condensed water generated from the exhaust gas depends on the amount of heat recovered from the exhaust gas by the heat exchanger. When the heat exchanger enables heat exchange between the exhaust gas and hot water, the amount of heat recovered from the exhaust gas by the heat exchanger is the temperature of the hot water supplied from the hot water storage tank and flowing into the heat exchanger. It depends on the hot water temperature, and the higher the inflow hot water temperature, the smaller the amount of heat recovered from the exhaust gas. Therefore, the amount of condensed water generated from the exhaust gas depends on the temperature of the inflowing hot water .

１つの態様として、前記貯湯タンクの下部から取り出した湯水を前記熱交換器に供給し、前記熱交換器を流れた湯水を前記貯湯タンクの上部に戻す循環路を備え、前記熱交換器は、前記排ガスと前記湯水とを熱交換可能であり、前記凝縮水発生量調節部として、前記貯湯タンクから湯水を排出する排湯路と、前記貯湯タンクの下部に接続される補給水路を介して前記貯湯タンクに前記排湯路から排出される湯水より低温の補給水を供給可能な補給水供給部と、を備え、前記運転制御部は、前記凝縮水増加処理として、前記排湯路を介して前記貯湯タンクから湯水を排出させ、且つ、前記補給水供給部から前記貯湯タンクに補給水を供給させる湯水排出運転を行わせると好適である。 In one aspect, pre-Symbol hot water taken out from the lower portion of the hot water storage tank is supplied to the heat exchanger, the hot water flowing through the said heat exchanger comprises a circulation path for returning the upper portion of the hot water storage tank, the heat exchanger , The exhaust gas and the hot water can be exchanged for heat, and as the condensed water generation amount adjusting unit, the hot water is discharged from the hot water storage tank via a hot water discharge channel and a make-up water channel connected to the lower part of the hot water storage tank. The hot water storage tank is provided with a make-up water supply unit capable of supplying make-up water having a temperature lower than that of the hot water discharged from the hot water drainage channel, and the operation control unit is provided with the operation control unit via the hot water drainage channel as the condensed water increasing process. It is preferable to perform a hot water discharge operation in which hot water is discharged from the hot water storage tank and the make-up water is supplied to the hot water storage tank from the make-up water supply unit.

この構成によれば、凝縮水増加処理として湯水排出運転を行って貯湯タンクの下部に低温の補給水を供給するので、熱交換器に低温の補給水が供給されることになる。その結果、熱交換器における熱回収の量が高められ、排ガスからの凝縮水の発生量を増加させることができる。これにより、燃料電池の出力を低減させることなく水タンク中の凝縮水の水位を維持することが可能になる。 According to this configuration, the hot water discharge operation is performed as the condensed water increasing treatment to supply the low temperature make-up water to the lower part of the hot water storage tank, so that the low temperature make-up water is supplied to the heat exchanger. As a result, the amount of heat recovery in the heat exchanger is increased, and the amount of condensed water generated from the exhaust gas can be increased. This makes it possible to maintain the water level of the condensed water in the water tank without reducing the output of the fuel cell.

１つの態様として、前記貯湯タンクと前記熱交換器との間で湯水を循環させる循環路を備え、前記熱交換器は、前記排ガスと前記湯水とを熱交換可能であり、前記凝縮水発生量調節部として、前記循環路を流れる湯水の単位時間当たりの流量を調節可能な流量調節部を備え、前記運転制御部は、前記凝縮水増加処理として、前記循環路を流れる湯水の単位時間当たりの流量を増加させると好適である。 In one aspect, includes a circulation path for circulating the hot water between the pre-Symbol hot water storage tank and the heat exchanger, the heat exchanger, and the hot water and the exhaust gas is possible heat exchange, the condensed water generated As the amount adjusting unit, a flow rate adjusting unit capable of adjusting the flow rate of hot water flowing through the circulation path per unit time is provided, and the operation control unit is used as the condensed water increasing process per unit time of hot water flowing through the circulation path. It is preferable to increase the flow rate of.

この構成によれば、凝縮水増加処理として熱交換器に供給する湯水の流量を増加させるので、熱交換器における熱回収の量が高められ、排ガスからの凝縮水の発生量を増加させることができる。これにより、燃料電池の出力を低減させることなく水タンク中の凝縮水の水位を維持することが可能になる。 According to this configuration, since the flow rate of hot water supplied to the heat exchanger is increased as the condensed water increasing treatment, the amount of heat recovery in the heat exchanger is increased, and the amount of condensed water generated from the exhaust gas can be increased. can. This makes it possible to maintain the water level of the condensed water in the water tank without reducing the output of the fuel cell.

第１実施形態に係る燃料電池システムの通常運転時を示す概略構成図Schematic block diagram showing normal operation of the fuel cell system according to the first embodiment 第１実施形態に係る燃料電池システムの凝縮水増加処理時を示す概略構成図Schematic block diagram showing the time of condensed water increase processing of the fuel cell system according to the first embodiment. 凝縮水増加処理のための制御を示すフローチャートFlowchart showing control for condensed water increase processing 第２実施形態に係る燃料電池システムの凝縮水増加処理時を示す概略構成図Schematic block diagram showing the time of condensed water increase processing of the fuel cell system according to the second embodiment. 第３実施形態に係る燃料電池システムの凝縮水増加処理時を示す概略構成図Schematic block diagram showing the time of condensed water increase processing of the fuel cell system according to the third embodiment. 第４実施形態に係る燃料電池システムの凝縮水増加処理時を示す概略構成図Schematic block diagram showing the time of condensed water increase processing of the fuel cell system according to the fourth embodiment. 第５実施形態に係る燃料電池システムの凝縮水増加処理時を示す概略構成図Schematic block diagram showing the time of condensed water increase processing of the fuel cell system according to the fifth embodiment.

〔第１の実施形態〕
本発明に係る燃料電池システムの第１の実施形態について、図面を参照して説明する。図１は、本実施形態に係る燃料電池システムを示し、本実施形態に係る燃料電池システムは、燃料ガス及び酸素ガスを反応させて発電する燃料電池１と、燃料電池１から排出される排ガスの熱を回収する熱交換器２と、湯水を蓄える貯湯タンク３と、熱交換器２による熱回収により排ガスから生じる凝縮水を回収する水タンク４と、を備えている。なお、図１に示すのはあくまでも本実施形態に係る燃料電池システムの説明に関連する構成のみを示してあり、他は省略してある（図２，４〜７についても同じ）。 [First Embodiment]
A first embodiment of the fuel cell system according to the present invention will be described with reference to the drawings. FIG. 1 shows a fuel cell system according to the present embodiment, and the fuel cell system according to the present embodiment is a fuel cell 1 that generates power by reacting fuel gas and oxygen gas, and exhaust gas discharged from the fuel cell 1. It includes a heat exchanger 2 for recovering heat, a hot water storage tank 3 for storing hot water, and a water tank 4 for recovering condensed water generated from exhaust gas by heat recovery by the heat exchanger 2. It should be noted that FIG. 1 shows only the configuration related to the description of the fuel cell system according to the present embodiment, and the others are omitted (the same applies to FIGS. 2, 4 to 7).

燃料電池１には、空気流路１１を介して空気（酸素ガスの一例）が供給され、原燃料流路１２を介して原燃料が供給される。そして、燃料電池１は原燃料を水蒸気改質して燃料ガスを生成する改質器を備え、原燃料流路１２を介して供給される原燃料から燃料ガスを生成し、供給された燃料ガス及び空気を反応させて発電するようになっている。そして、燃料電池１は、燃料ガス中に残存する燃料成分を燃焼させて排ガスを生じさせるようになっている。つまり、燃料電池１には、発電反応に用いられた燃料ガス中に残存する燃料成分を燃焼させて排ガスを生じさせる燃焼部（図示せず）が設けられている。なお、後述するように、原燃料流路１２には水タンク４から水が供給されるようになっており、改質器が水タンク４からの水を用いて原燃料の水蒸気改質を行うようになっている。 Air (an example of oxygen gas) is supplied to the fuel cell 1 via the air flow path 11, and raw fuel is supplied via the raw material / fuel flow path 12. The fuel cell 1 is provided with a reformer that steam reforms the raw fuel to generate fuel gas, generates fuel gas from the raw fuel supplied via the raw fuel flow path 12, and supplies the fuel gas. And air is made to react to generate electricity. Then, the fuel cell 1 burns the fuel component remaining in the fuel gas to generate exhaust gas. That is, the fuel cell 1 is provided with a combustion unit (not shown) that burns the fuel component remaining in the fuel gas used for the power generation reaction to generate exhaust gas. As will be described later, water is supplied to the raw material / fuel flow path 12 from the water tank 4, and the reformer performs steam reforming of the raw material / fuel using the water from the water tank 4. It has become like.

熱交換器２には、燃料電池１から熱交換器２に排ガスを供給する排ガス配管２５を介して燃料電池１から排出される排ガスが供給され、熱回収後の排ガスが排ガス排出路２６を介して排気されるようになっている。そして、熱交換器２には、湯水を貯える貯湯タンク３の下部から取り出した湯水を熱交換器２に供給し、熱交換器２を流れた湯水を貯湯タンク３の上部に戻して貯湯タンク３と熱交換器２との間で湯水を循環させる循環路２１を介して貯湯タンク３からの湯水が供給されるようになっており、熱交換器２は、燃料電池１から排出される排ガスと湯水とを熱交換させるようになっている。なお、循環路２１には、湯水を循環させるポンプ２２、放熱ファン２３ａを備える放熱器２３が設けられており、後述する運転制御部がポンプ２２及び放熱器２３の運転を制御するようになっている。また、循環路２１には、貯湯タンク３から供給されて熱交換器２に流入する湯水の温度である流入湯水温度を取得する温度センサ２４が設けられている。なお、詳しくは後述するが、温度センサ２４は、排ガスから生じる凝縮水の量に関連する凝縮水情報を取得する凝縮水情報取得部として機能する。 Exhaust gas discharged from the fuel cell 1 is supplied to the heat exchanger 2 via an exhaust gas pipe 25 that supplies exhaust gas from the fuel cell 1 to the heat exchanger 2, and the exhaust gas after heat recovery passes through the exhaust gas discharge path 26. It is designed to be exhausted. Then, to the heat exchanger 2, the hot water taken out from the lower part of the hot water storage tank 3 for storing the hot water is supplied to the heat exchanger 2, and the hot water flowing through the heat exchanger 2 is returned to the upper part of the hot water storage tank 3 to return the hot water to the upper part of the hot water storage tank 3. The hot water from the hot water storage tank 3 is supplied through the circulation path 21 that circulates the hot water between the heat exchanger 2 and the heat exchanger 2, and the heat exchanger 2 is the exhaust gas discharged from the fuel cell 1. It is designed to exchange heat with hot water. The circulation path 21 is provided with a radiator 23 including a pump 22 for circulating hot water and a radiator fan 23a, and an operation control unit described later controls the operation of the pump 22 and the radiator 23. There is. Further, the circulation path 21 is provided with a temperature sensor 24 for acquiring the inflow hot water temperature, which is the temperature of the hot water supplied from the hot water storage tank 3 and flowing into the heat exchanger 2. As will be described in detail later, the temperature sensor 24 functions as a condensed water information acquisition unit that acquires condensed water information related to the amount of condensed water generated from the exhaust gas.

貯湯タンク３は、循環路２１を介して熱交換器２により熱交換されて昇温した湯水を貯留する。また、貯湯タンク３には、貯留タンク３中の湯水を給湯器３２に出湯するための出湯路３１、及び、湯水の出湯に応じて貯留タンク３に補給水を給水するための補給水路路３３が設けられている。 The hot water storage tank 3 stores hot water that has been heated by heat exchange by the heat exchanger 2 via the circulation path 21. Further, the hot water storage tank 3 has a hot water outlet 31 for discharging the hot water in the storage tank 3 to the water heater 32, and a supplementary water channel 33 for supplying supplementary water to the storage tank 3 according to the hot water discharge. Is provided.

水タンク４は、熱交換器２による熱回収により排ガスから生じる凝縮水を回収するものである。そして、本実施形態では、第１凝縮水回収路４１を介して、熱交換器２による熱回収により生じた凝縮水を水精製器４２により回収して精製した後、第２凝縮水回収路４３を介して精製後の凝縮水を水タンク４に回収するようにしてある。また、水タンク４には水位検出器４４が設けられており、水タンク４に貯えられている水の量である貯水量を水位として取得可能になっている。なお、詳しくは後述するが、水位検出器４４は、排ガスから生じる凝縮水の量に関連する凝縮水情報を取得する凝縮水情報取得部として機能する。また、水タンク４には、水タンク４中の凝縮水を原燃料流路１２に供給する凝縮水供給路４５を設けてあり、ポンプ４６により原燃料流路１２に水タンク４中の凝縮水を供給可能になっている。 The water tank 4 recovers condensed water generated from exhaust gas by heat recovery by the heat exchanger 2. Then, in the present embodiment, the condensed water generated by the heat recovery by the heat exchanger 2 is recovered and purified by the water purifier 42 via the first condensed water recovery path 41, and then the second condensed water recovery path 43 is used. The condensed water after purification is collected in the water tank 4 through the water tank 4. Further, the water tank 4 is provided with a water level detector 44, and the water storage amount, which is the amount of water stored in the water tank 4, can be acquired as the water level. As will be described in detail later, the water level detector 44 functions as a condensed water information acquisition unit that acquires condensed water information related to the amount of condensed water generated from the exhaust gas. Further, the water tank 4 is provided with a condensed water supply path 45 for supplying the condensed water in the water tank 4 to the raw material / fuel flow path 12, and the condensed water in the water tank 4 is provided in the raw material / fuel flow path 12 by the pump 46. Can be supplied.

また、燃料電池システムは、図示しない例えばマイコン等の運転制御部を備え、システムを構成する各部の運転を制御するようになっている。例えば、運転制御部は、循環路２１における貯湯タンク３の入口側及び出口側の湯水の温度に基づき、適切な量の湯水が熱交換器２に供給されるようにポンプ２２を運転させたり、放熱器２３により循環路２１中の湯水の放熱を行わせるようになっている。 Further, the fuel cell system includes an operation control unit such as a microcomputer (not shown), and controls the operation of each unit constituting the system. For example, the operation control unit may operate the pump 22 so that an appropriate amount of hot water is supplied to the heat exchanger 2 based on the temperature of the hot water on the inlet side and the outlet side of the hot water storage tank 3 in the circulation path 21. The radiator 23 is designed to dissipate hot water in the circulation path 21.

以上のように、本実施形態に係る燃料電池システムでは、基本的に、燃料電池１から排出される排ガスを熱交換器２により湯水と熱交換させて排ガスを冷却し、冷却により排ガスから生じる凝縮水を水タンク４に回収し、回収した凝縮水を燃料電池１側に供給して燃料電池１の発電に利用する、といった形態で運転を行うようになっている。ただし、この場合、排ガスから回収できる凝縮水の量が少なくなると水タンク４中の凝縮水が不足することになり、その結果、システムの運転を行えなくなる。そこで、本実施形態に係る燃料電池システムでは、排ガスから回収できる凝縮水の量が減少傾向にある場合に、これを解消するための排ガスから生じる凝縮水の量を調節可能な構成を採用している。以下、かかる構成について説明する。 As described above, in the fuel cell system according to the present embodiment, basically, the exhaust gas discharged from the fuel cell 1 is heat-exchanged with hot water by the heat exchanger 2 to cool the exhaust gas, and the condensation generated from the exhaust gas by cooling is performed. The operation is performed in such a manner that water is collected in a water tank 4 and the collected condensed water is supplied to the fuel cell 1 side to be used for power generation of the fuel cell 1. However, in this case, if the amount of condensed water that can be recovered from the exhaust gas becomes small, the condensed water in the water tank 4 becomes insufficient, and as a result, the system cannot be operated. Therefore, in the fuel cell system according to the present embodiment, when the amount of condensed water that can be recovered from the exhaust gas tends to decrease, a configuration is adopted in which the amount of condensed water generated from the exhaust gas can be adjusted in order to eliminate this. There is. Hereinafter, such a configuration will be described.

まず、本実施形態に係る燃料電池システムでは、排ガスから回収できる凝縮水の量が減少傾向にある場合に排ガスから生じる凝縮水の量を調節するため、排ガスから生じる凝縮水の量に関連する凝縮水情報を取得する凝縮水情報取得部と、排ガスから生じる凝縮水の量を調節可能な凝縮水発生量調節部と、を設けて、運転制御部により、凝縮水情報が、凝縮水の量が減少傾向にあることを示す所定の凝縮水減少条件を満たすとき、凝縮水情報が所定の凝縮水増加条件を満たすまで、凝縮水発生量調節部に排ガス中から単位時間当たりに回収できる凝縮水の量を増加させる凝縮水増加処理を行わせるようになっている。つまり、本実施形態に係る燃料電池システムでは、凝縮水の量が減少傾向にあるときに凝縮水発生量調節部により凝縮水増加処理を行わせるようにして、水タンク４中の凝縮水の水位を維持するようになっている。 First, in the fuel cell system according to the present embodiment, in order to adjust the amount of condensed water generated from the exhaust gas when the amount of condensed water that can be recovered from the exhaust gas tends to decrease, the condensation related to the amount of condensed water generated from the exhaust gas is condensed. A condensed water information acquisition unit that acquires water information and a condensed water generation amount adjusting unit that can adjust the amount of condensed water generated from exhaust gas are provided, and the operation control unit provides condensed water information and the amount of condensed water. Condensed water that can be recovered from the exhaust gas per unit time by the condensed water generation amount adjustment unit until the condensed water information satisfies the predetermined condensed water increase condition when the predetermined condensed water decrease condition indicating the decreasing tendency is satisfied. Condensed water increase treatment to increase the amount is performed. That is, in the fuel cell system according to the present embodiment, when the amount of condensed water tends to decrease, the condensed water generation amount adjusting unit is made to perform the condensed water increasing treatment, and the water level of the condensed water in the water tank 4 is performed. Is designed to be maintained.

具体的には、本実施形態では、凝縮水情報取得部として温度センサ２４及び水位検出器４４を用い、運転制御部は、凝縮水情報として、熱交換器２に流入する湯水の温度である流入湯水温度と、水タンク４の水位（水タンク４の貯水量の一例）とを取得するようになっている。そして、凝縮水の量が減少傾向にあると判断するための設定温度と設定下限水位（設定下限水量の一例）とを定めてあり、運転制御部は、流入湯水温度が上昇して設定温度になり、且つ、水位（貯水量）が減少して設定下限水位になると凝縮水減少条件が満たされていると判定するようになっている。つまり、流入湯水温度が高いほど排ガスの冷却量が小さくなって、その結果、凝縮水の発生量が減少するので、流入湯水温度を凝縮水情報として取得すれば、凝縮水の量が減少傾向にあることを判定可能である。また、水タンク４の水位は凝縮水の量が減少していることを直接に示す指標である。このように、本実施形態では、これら２つの指標を用いることで、凝縮水の量が減少傾向であることを確度高く判定可能になっている。 Specifically, in the present embodiment, the temperature sensor 24 and the water level detector 44 are used as the condensed water information acquisition unit, and the operation control unit uses the temperature of the hot water flowing into the heat exchanger 2 as the condensed water information. The hot water temperature and the water level of the water tank 4 (an example of the amount of water stored in the water tank 4) are acquired. Then, the set temperature and the set lower limit water level (an example of the set lower limit water amount) for determining that the amount of condensed water is decreasing are set, and the operation control unit raises the inflow hot water temperature to the set temperature. When the water level (reservoir amount) decreases and the set lower limit water level is reached, it is determined that the condensed water reduction condition is satisfied. In other words, the higher the inflow hot water temperature, the smaller the cooling amount of the exhaust gas, and as a result, the amount of condensed water generated decreases. Therefore, if the inflow hot water temperature is acquired as condensed water information, the amount of condensed water tends to decrease. It is possible to determine that there is. Further, the water level of the water tank 4 is an index directly indicating that the amount of condensed water is decreasing. As described above, in the present embodiment, by using these two indexes, it is possible to determine with high accuracy that the amount of condensed water tends to decrease.

また、本実施形態では、凝縮水発生量調節部として熱交換器２に貯湯タンク３中の湯水よりも低温の冷却液（例えばクーラント液）を供給可能な冷却液供給部５を備えている。具体的には、ポンプ５３を駆動させることにより、冷却水供給路５１と冷却水回収路５２とを介して熱交換器２と冷却液供給部５との間で冷却液を循環可能になっている。そして、運転制御部は、熱交換器２を、排ガスと湯水との熱交換を行う湯水利用状態（図１）と、排ガスと冷却液との熱交換が可能な冷却液利用状態（図２）とに切替可能になっており、凝縮水増加処理として、熱交換器２を冷却液利用状態とし、冷却液供給部５に熱交換器２へ冷却液を供給させるようになっている。即ち、運転制御部は、通常運転時は熱交換器２を湯水利用状態にしつつ、凝縮水が減少傾向にあるときにのみ熱交換器２を冷却液利用状態とする。そして、湯水よりも低温の冷却液を熱交換器２に供給することで排ガスの冷却量を大きくできるので、凝縮水の発生量を増加させることができる。 Further, in the present embodiment, the heat exchanger 2 is provided with a coolant supply unit 5 capable of supplying a coolant (for example, a coolant) having a temperature lower than that of the hot water in the hot water storage tank 3 as a condensed water generation amount adjusting unit. Specifically, by driving the pump 53, the coolant can be circulated between the heat exchanger 2 and the coolant supply unit 5 via the cooling water supply path 51 and the cooling water recovery path 52. There is. Then, the operation control unit uses the heat exchanger 2 in a hot water utilization state in which heat is exchanged between the exhaust gas and hot water (FIG. 1) and a coolant utilization state in which heat exchange between the exhaust gas and the coolant is possible (FIG. 2). As a treatment for increasing the amount of condensed water, the heat exchanger 2 is put into a state where the coolant is used, and the coolant supply unit 5 is made to supply the coolant to the heat exchanger 2. That is, the operation control unit puts the heat exchanger 2 in the hot water utilization state during normal operation, and puts the heat exchanger 2 in the coolant utilization state only when the condensed water tends to decrease. Then, by supplying the heat exchanger 2 with a cooling liquid having a temperature lower than that of the hot water, the cooling amount of the exhaust gas can be increased, so that the amount of condensed water generated can be increased.

なお、湯水利用状態にあるときには湯水のみを熱交換器２に供給し、冷却液利用状態にあるときには冷却液のみを熱交換器２に供給するという図１，２に示す構成に限らず、冷却液利用状態にあるときには湯水との熱交換と併行して冷却液による熱交換を可能にする構成を採用してもよい。この場合、熱交換器２内では、排ガスと冷却液との熱交換、及び、排ガスと湯水との熱交換が行われ、冷却液と湯水との熱交換が行われないように構成することが好ましく、また、熱交換器２内において、先に、排ガスと湯水との熱交換が行われ、その後、排ガスと冷却液との熱交換が行われるように構成することが好ましい。
また、冷却液供給部５、冷却水供給路５１、及び、冷却水回収路５２のいずれかには図示しない放熱器を設けてあり、冷却液を放熱させて熱交換器２に供給する冷却液を低温に保つことが可能になっている。 The cooling is not limited to the configuration shown in FIGS. 1 and 2 in which only the hot water is supplied to the heat exchanger 2 when the hot water is in use, and only the coolant is supplied to the heat exchanger 2 when the coolant is in use. When the liquid is in use, a configuration may be adopted that enables heat exchange with the coolant in parallel with heat exchange with hot water. In this case, in the heat exchanger 2, heat exchange between the exhaust gas and the coolant and heat exchange between the exhaust gas and the hot water are performed, and the heat exchange between the coolant and the hot water may not be performed. It is preferable that the heat exchanger 2 is configured such that heat exchange between the exhaust gas and hot water is performed first, and then heat exchange between the exhaust gas and the coolant is performed.
Further, a radiator (not shown) is provided in any of the coolant supply unit 5, the cooling water supply path 51, and the cooling water recovery path 52, and the coolant is dissipated and supplied to the heat exchanger 2. It is possible to keep the temperature low.

そして、本実施形態では、凝縮水増加処理を終了させる凝縮水増加条件として、凝縮水増加処理を行う時間と目標とする水タンクの水位（貯水量）とを採用し、運転制御部は、凝縮水発生量調節部として冷却液供給部５に凝縮水増加処理を行わせた時間が所定時間に達するか、又は、水位が増加して目標水位（目標水量）になると凝縮水増加条件が満たされていると判定するようになっている。 Then, in the present embodiment, the time for performing the condensed water increasing treatment and the target water level (water storage amount) of the water tank are adopted as the conditions for increasing the condensed water to end the condensed water increasing treatment, and the operation control unit condenses. When the time for which the coolant supply unit 5 is allowed to perform the condensed water increasing treatment as the water generation amount adjusting unit reaches a predetermined time, or when the water level increases and reaches the target water level (target water amount), the condensed water increasing condition is satisfied. It is designed to determine that.

具体的には、本実施形態では、運転制御部は、図３のフローチャートのような手順で処理を行う。つまり、まず、運転制御部は、温度センサ２４が取得する流入湯水温度と水位検出器４４が取得する水タンク４の貯水量である水位との凝縮水情報が、上記のような凝縮水減少条件を満たすかを判定する（＃１）。そして、凝縮水減少条件を満たしていない場合には通常運転（本実施形態では湯水利用状態の運転）を継続し（＃１：Ｎｏ）、凝縮水減少条件を満たしている場合には（＃１：Ｙｅｓ）凝縮水増加処理を実行する（＃２）。その後、凝縮水増加条件を満たすまで凝縮水増加処理を継続し（＃３：Ｎｏ）、凝縮水増加条件を満たしたとき（＃３：Ｙｅｓ）凝縮水増加処理を終了して通常運転に戻り、＃１に戻る。 Specifically, in the present embodiment, the operation control unit performs processing according to the procedure as shown in the flowchart of FIG. That is, first, in the operation control unit, the condensed water information of the inflow hot water temperature acquired by the temperature sensor 24 and the water level which is the water storage amount of the water tank 4 acquired by the water level detector 44 is the condition for reducing the condensed water as described above. It is determined whether the condition is satisfied (# 1). Then, if the condensed water reduction condition is not satisfied, the normal operation (operation in the hot water utilization state in this embodiment) is continued (# 1: No), and if the condensed water reduction condition is satisfied (# 1). : Yes) Condensed water increase processing is executed (# 2). After that, the condensed water increasing treatment is continued until the condensed water increasing condition is satisfied (# 3: No), and when the condensed water increasing condition is satisfied (# 3: Yes), the condensed water increasing treatment is completed and the normal operation is resumed. Return to # 1.

〔第２の実施形態〕
本発明に係る燃料電池システムの第２の実施形態について、図４を参照して説明する。本実施形態では、凝縮水発生量調節部として冷却ファン６を用いている点で他の実施形態と異なっている。以下、本実施形態に係る燃料電池システムについて、主に第１の実施形態との相違点について説明する。なお、特に明記しない点に関しては、第１の実施形態と同様であり、同一の符号を付して詳細な説明は省略する。 [Second Embodiment]
A second embodiment of the fuel cell system according to the present invention will be described with reference to FIG. This embodiment is different from other embodiments in that the cooling fan 6 is used as the condensed water generation amount adjusting unit. Hereinafter, the difference between the fuel cell system according to the present embodiment and the first embodiment will be mainly described. It should be noted that the points not particularly specified are the same as those in the first embodiment, and the same reference numerals are given and detailed description thereof will be omitted.

本実施形態に係る燃料電池システムでは、図４に示すように、凝縮水発生量調節部として、冷却液供給部５に代えて、排ガス配管２５を冷却して排ガス配管２５を介した排ガスからの放熱状態を調節可能な冷却ファン６を備え、運転制御部は、凝縮水増加処理として、冷却液供給部５からの冷却液の供給に代えて、冷却ファン６を動作させるようになっている。つまり、本実施形態では、冷却ファン６を動作させることで排ガス配管２５を介して排ガスを冷却し、排ガスからの凝縮水の発生量を増加させるようになっている。なお、凝縮水減少条件及び凝縮水増加条件の判定等の運転制御部の処理フローに関しては、凝縮水増加処理として冷却ファン６を動作させることを除き、第１の実施形態と異ならないので説明は省略する。 In the fuel cell system according to the present embodiment, as shown in FIG. 4, the exhaust gas pipe 25 is cooled instead of the coolant supply unit 5 as the condensed water generation amount adjusting unit, and the exhaust gas is discharged from the exhaust gas via the exhaust gas pipe 25. A cooling fan 6 whose heat dissipation state can be adjusted is provided, and the operation control unit operates the cooling fan 6 instead of supplying the cooling liquid from the cooling liquid supply unit 5 as a process for increasing the condensed water. That is, in the present embodiment, the exhaust gas is cooled through the exhaust gas pipe 25 by operating the cooling fan 6, and the amount of condensed water generated from the exhaust gas is increased. The processing flow of the operation control unit such as determination of the condensed water decreasing condition and the condensed water increasing condition is not different from the first embodiment except that the cooling fan 6 is operated as the condensed water increasing processing. Omit.

〔第３の実施形態〕
本発明に係る燃料電池システムの第３の実施形態について、図５を参照して説明する。本実施形態では、凝縮水発生量調節部として排湯路３４等を用いている点で他の実施形態と異なっている。以下、本実施形態に係る燃料電池システムについて、主に第１の実施形態との相違点について説明する。なお、特に明記しない点に関しては、第１の実施形態と同様であり、同一の符号を付して詳細な説明は省略する。 [Third Embodiment]
A third embodiment of the fuel cell system according to the present invention will be described with reference to FIG. This embodiment is different from other embodiments in that a hot water drainage channel 34 or the like is used as the condensed water generation amount adjusting unit. Hereinafter, the difference between the fuel cell system according to the present embodiment and the first embodiment will be mainly described. It should be noted that the points not particularly specified are the same as those in the first embodiment, and the same reference numerals are given and detailed description thereof will be omitted.

本実施形態に係る燃料電池システムでは、図５に示すように、凝縮水発生量調節部として、貯湯タンク３から湯水を排出する排湯路３４を設けてあり、また、貯湯タンク３の下部に接続される補給水路３３を介して貯湯タンク３に補給水を供給可能な補給水供給部（図示は省略してある）が凝縮水発生量調節部として機能するようになっている。なお、補給水の温度は排湯路３４から排出される湯水より少なくとも低温になっている。そして、運転制御部は、凝縮水増加処理として、排湯路３４を介して貯湯タンク３から湯水を排出させ、且つ、補給水供給部から貯湯タンク３に補給水をさせる湯水排出運転を行わせるようになっている。つまり、凝縮水増加処理として湯水排出運転を行うことで貯湯タンク３の下部に低温の補給水を供給するので、熱交換器２に低温の補給水が供給されることになる。そして、その結果、熱交換器２における排ガスの冷却量が高まって排ガスからの凝縮水の発生量を増加させることができる。 In the fuel cell system according to the present embodiment, as shown in FIG. 5, a hot water drainage channel 34 for discharging hot water from the hot water storage tank 3 is provided as a condensed water generation amount adjusting unit, and a hot water drainage channel 34 is provided at the lower part of the hot water storage tank 3. A make-up water supply unit (not shown) capable of supplying make-up water to the hot water storage tank 3 via the connected make-up water channel 33 functions as a condensed water generation amount adjusting unit. The temperature of the make-up water is at least lower than that of the hot water discharged from the hot water drainage channel 34. Then, the operation control unit performs a hot water discharge operation in which the hot water is discharged from the hot water storage tank 3 through the hot water drainage channel 34 and the hot water storage tank 3 is supplied with the hot water from the make-up water supply unit as a process for increasing the condensed water. It has become like. That is, since the low-temperature make-up water is supplied to the lower part of the hot water storage tank 3 by performing the hot water discharge operation as the condensed water increasing process, the low-temperature make-up water is supplied to the heat exchanger 2. As a result, the cooling amount of the exhaust gas in the heat exchanger 2 is increased, and the amount of condensed water generated from the exhaust gas can be increased.

なお、本実施形態では、凝縮水増加処理として湯水排出運転を行うのを、凝縮水減少条件のみならず所定の湯水排出運転条件を満たしている場合に限り行うようにしてある。つまり、貯湯タンク３の下部における水の温度が十分低い場合には、湯水を排出して新たに補給水を供給しても凝縮水の増加には寄与せず、凝縮水の増加させるためには他の凝縮水増加処理を行う必要がある。そして、湯水排出運転条件として、給湯器３２への湯水の供給がない状態が一定時間経過したことや、貯湯タンク３の下部の水の温度を計測するようにして、その温度が予め定めた基準温度以下であることを基準とすることが挙げられる。 In this embodiment, the hot water discharge operation is performed as the condensed water discharge increase treatment only when the predetermined hot water discharge operation condition is satisfied as well as the condensed water decrease condition. That is, when the temperature of the water in the lower part of the hot water storage tank 3 is sufficiently low, even if the hot water is discharged and new make-up water is supplied, it does not contribute to the increase of the condensed water, and in order to increase the condensed water. It is necessary to perform other condensed water increase treatment. Then, as the hot water discharge operation condition, the state where the hot water is not supplied to the water heater 32 has elapsed for a certain period of time, and the temperature of the water at the lower part of the hot water storage tank 3 is measured, and the temperature is a predetermined standard. The standard is that the temperature is below the temperature.

また、一回の凝縮水増加処理で湯水が全て排出されると給湯器３２への湯水の供給ができなくなるので、本実施形態では、一回の凝縮水増加処理で貯湯タンク３中の湯水が全て排出されないようにしてある。具体的には、凝縮水増加条件としての凝縮水増加処理を行う時間を、貯湯タンク３中の湯水が全て排出されない時間（例えば、貯湯タンク３中の湯水の量の半分が排出される時間）としたり、排湯路３４から排出される湯水の量や補給水路３３から供給される補給水の量を計測するようにして、その計測量が一定量に達したときに凝縮水増加条件が満たされたと判定するようにしてもよい。 Further, if all the hot water is discharged in one condensed water increase treatment, the hot water cannot be supplied to the water heater 32. Therefore, in the present embodiment, the hot water in the hot water storage tank 3 is discharged by one condensed water increase treatment. All are not discharged. Specifically, the time for performing the condensed water increasing treatment as a condition for increasing the condensed water is the time during which all the hot water in the hot water storage tank 3 is not discharged (for example, the time when half of the amount of hot water in the hot water storage tank 3 is discharged). Or, the amount of hot water discharged from the hot water drainage channel 34 and the amount of make-up water supplied from the make-up water channel 33 are measured, and when the measured amount reaches a certain amount, the condition for increasing condensed water is satisfied. It may be determined that it has been done.

〔第４の実施形態〕
本発明に係る燃料電池システムの第４の実施形態について、図６を参照して説明する。本実施形態では、凝縮水発生量調節部として放熱器２３を用いている点で第１の実施形態と異なっている。以下、本実施形態に係る燃料電池システムについて、主に第１の実施形態との相違点について説明する。なお、特に明記しない点に関しては、第１の実施形態と同様であり、同一の符号を付して詳細な説明は省略する。 [Fourth Embodiment]
A fourth embodiment of the fuel cell system according to the present invention will be described with reference to FIG. This embodiment is different from the first embodiment in that the radiator 23 is used as the condensed water generation amount adjusting unit. Hereinafter, the difference between the fuel cell system according to the present embodiment and the first embodiment will be mainly described. It should be noted that the points not particularly specified are the same as those in the first embodiment, and the same reference numerals are given and detailed description thereof will be omitted.

本実施形態に係る燃料電池システムでは、図６に示すように、凝縮水発生量調節部として、熱交換器２の上流側において、循環路２１を流れる湯水を放熱させる放熱器２３を用いており、運転制御部は、凝縮水情報が凝縮水減少条件を満たしていないときは、温度センサ２４で取得される流入湯水温度（熱交換器２に流入する湯水の温度）が所定温度を超えているときに放熱器２３を所定の運転量で動作させ、凝縮水情報が凝縮水減少条件を満たしているときは、凝縮水増加処理として放熱器２３を所定の運転量を超える運転量で動作させるようになっている。つまり、通常時（凝縮水情報が凝縮水減少条件を満たしていないとき）は、流入湯水温度が所定温度（例えば４０℃）を超えないように、流入湯水温度が所定温度を下回る限度の所定の運転量で放熱器２３を運転させるに過ぎないが、凝縮水情報が凝縮水減少条件を満たしているときには、これを超える運転量で放熱器２３を動作させて熱交換器２に供給される湯水の温度を過度に低下させて熱交換器２における熱回収の量を高め、これにより、排ガスからの凝縮水の発生量を増加させる。そして、本実施形態では、放熱ファン２３ａを運転させて湯水を放熱させるところ、所定の運転量を超える運転量で放熱ファン２３ａを運転させる場合には、放熱ファン２３ａの運転に伴い過度の騒音が生じることとなるため、夜間には凝縮水増加処理として放熱器２３を動作させないようになっている（つまり、所定の運転量を超える運転量で放熱ファン２３ａを運転させないようになっている）。具体的には、凝縮水増加処理として放熱器２３を動作させるのを、凝縮水減少条件のみならず、さらに、放熱器運転条件として予め定めた運転可能時間帯にのみ放熱器２３を動作させるようにしてある。 In the fuel cell system according to the present embodiment, as shown in FIG. 6, as a condensed water generation amount adjusting unit, a radiator 23 that dissipates hot water flowing through the circulation path 21 is used on the upstream side of the heat exchanger 2. When the condensed water information does not satisfy the condensed water reduction condition, the operation control unit indicates that the inflow hot water temperature (the temperature of the hot water flowing into the heat exchanger 2) acquired by the temperature sensor 24 exceeds a predetermined temperature. Occasionally, the radiator 23 is operated at a predetermined operating amount, and when the condensed water information satisfies the condensed water decreasing condition, the radiator 23 is operated at an operating amount exceeding the predetermined operating amount as a condensed water increasing process. It has become. That is, in the normal state (when the condensed water information does not satisfy the condensate reduction condition), the inflow hot water temperature is a predetermined limit below the predetermined temperature so that the inflow hot water temperature does not exceed the predetermined temperature (for example, 40 ° C.). The radiator 23 is only operated by the operating amount, but when the condensed water information satisfies the condensate reduction condition, the hot water supplied to the heat exchanger 2 by operating the radiator 23 with an operating amount exceeding this. The temperature of the heat exchanger 2 is excessively lowered to increase the amount of heat recovery in the heat exchanger 2, thereby increasing the amount of condensed water generated from the exhaust gas. In the present embodiment, the heat radiating fan 23a is operated to dissipate hot water. However, when the heat radiating fan 23a is operated with an operating amount exceeding a predetermined operating amount, excessive noise is generated due to the operation of the heat radiating fan 23a. Therefore, the heat radiating fan 23 is not operated as a condensed water increasing process at night (that is, the heat radiating fan 23a is not operated with an operating amount exceeding a predetermined operating amount). Specifically, the radiator 23 is operated not only under the condition for reducing the condensed water but also during the operable time zone predetermined as the condition for operating the radiator so that the radiator 23 is operated as the process for increasing the condensed water. It is set to.

〔第５の実施形態〕
本発明に係る燃料電池システムの第５の実施形態について、図７を参照して説明する。本実施形態では、凝縮水発生量調節部としてポンプ２２を用いている点で他の実施形態と異なっている。以下、本実施形態に係る燃料電池システムについて、主に第１の実施形態との相違点について説明する。なお、特に明記しない点に関しては、第１の実施形態と同様であり、同一の符号を付して詳細な説明は省略する。 [Fifth Embodiment]
A fifth embodiment of the fuel cell system according to the present invention will be described with reference to FIG. 7. This embodiment is different from other embodiments in that the pump 22 is used as the condensed water generation amount adjusting unit. Hereinafter, the difference between the fuel cell system according to the present embodiment and the first embodiment will be mainly described. It should be noted that the points not particularly specified are the same as those in the first embodiment, and the same reference numerals are given and detailed description thereof will be omitted.

本実施形態に係る燃料電池システムでは、図７に示すように、凝縮水発生量調節部として、冷却液供給部５に代えて、循環路２１を流れる湯水の単位時間当たりの流量を調節可能な流量調節部としてのポンプ２２を用いており、運転制御部は、凝縮水増加処理として、循環路２１を流れる湯水の単位時間当たりの流量を増加させるようになっている。つまり、熱交換器２に供給する湯水の流量を増加させて、熱交換器２における熱回収の量が高められ、排ガスからの凝縮水の発生量を増加させることができる。 In the fuel cell system according to the present embodiment, as shown in FIG. 7, as the condensed water generation amount adjusting unit, the flow rate of hot water flowing through the circulation path 21 per unit time can be adjusted instead of the coolant supply unit 5. A pump 22 is used as a flow rate adjusting unit, and the operation control unit increases the flow rate of hot water flowing through the circulation path 21 per unit time as a process for increasing the condensed water. That is, the flow rate of the hot water supplied to the heat exchanger 2 can be increased, the amount of heat recovery in the heat exchanger 2 can be increased, and the amount of condensed water generated from the exhaust gas can be increased.

〔別実施形態〕
（１）上述の実施形態では、第１〜第５の実施形態でそれぞれ異なる凝縮水発生量調節部を用いて凝縮水増加処理を行う構成を例に説明した。しかし、凝縮水発生量調節部として、第１〜第５の実施形態で示したものの全て、又は、２以上の組み合わせを採用するようにして、採用した各凝縮水発生量調節部で実行される凝縮水増加処理を併行して実行させたり、順番に実行させたり、又は、予め定めた基準や条件に従ってその中から１つを選択して実行させるようにしてもよい。その場合、各凝縮水発生量調節部で実行される凝縮水増加処理について、上記した湯水排出運転条件や放熱器運転条件のように発動条件を定めておき、その発動条件を満たしたもののみを実行したり、複数段階の異なる凝縮水増加処理を定めておき、各段階の凝縮水増加処理によっても凝縮水減少条件を依然として満たしている場合に、次の段階の凝縮水増加処理を行わせるようにしてもよい。また、排ガスから生じる凝縮水の量を調節可能な凝縮水発生量調節部は上述の実施形態で示したものに限られず、種々のものを用いることができる。 [Another Embodiment]
(1) In the above-described embodiment, the configuration in which the condensed water increasing treatment is performed using different condensed water generation amount adjusting units in the first to fifth embodiments has been described as an example. However, as the condensed water generation amount adjusting unit, all of those shown in the first to fifth embodiments, or a combination of two or more is adopted, and the condensed water generation amount adjusting unit is executed. The condensed water increasing treatment may be executed in parallel, or may be executed in order, or one of them may be selected and executed according to a predetermined standard or condition. In that case, for the condensed water increase processing executed by each condensed water generation amount adjustment unit, the activation conditions such as the above-mentioned hot water discharge operation conditions and radiator operation conditions are set, and only those that satisfy the activation conditions are selected. If it is executed or multiple stages of different condensed water increase treatments are defined and the condensed water decrease conditions are still satisfied by each stage of the condensed water increase treatment, the next stage of the condensed water increase treatment is performed. It may be. Further, the condensed water generation amount adjusting unit capable of adjusting the amount of condensed water generated from the exhaust gas is not limited to the one shown in the above-described embodiment, and various types can be used.

（２）上述の実施形態では、凝縮水情報取得部として温度センサ２４及び水位検出器４４を用い、運転制御部は、凝縮水情報として、熱交換器２に流入する湯水の温度である流入湯水温度と、水タンク４の貯水量である水位とを取得し、流入湯水温度が上昇して設定温度になり、且つ、水位が減少して設定下限水位になると凝縮水減少条件が満たされていると判定する構成を例に説明した。しかし、運転制御部は、流入湯水温度が上昇して設定温度になるか、水位が減少して設定下限水位になるかのいずれかを満たしたときに凝縮水減少条件が満たされていると判定してもよい。また、凝縮水情報取得部、運転制御部、及び、凝縮水減少条件は上記したものに限られず、種々のものを採用することができる。 (2) In the above-described embodiment, the temperature sensor 24 and the water level detector 44 are used as the condensed water information acquisition unit, and the operation control unit uses the inflow hot water which is the temperature of the hot water flowing into the heat exchanger 2 as the condensed water information. When the temperature and the water level, which is the amount of water stored in the water tank 4, are acquired, the inflow hot water temperature rises to the set temperature, and the water level decreases to the set lower limit water level, the condensate water reduction condition is satisfied. The configuration for determining that is described as an example. However, the operation control unit determines that the condensed water reduction condition is satisfied when either the inflow hot water temperature rises to the set temperature or the water level decreases to the set lower limit water level. You may. Further, the condensed water information acquisition unit, the operation control unit, and the condensed water reduction conditions are not limited to those described above, and various ones can be adopted.

（３）上述の実施形態では、運転制御部は、冷却液供給部５に凝縮水増加処理を行わせた時間が所定時間に達するか、又は、水位が増加して目標水位になると凝縮水増加条件が満たされていると判定する構成を例に説明した。しかし、凝縮水増加条件は上記したものに限られず、種々のものを採用することができる。 (3) In the above-described embodiment, the operation control unit increases the condensed water when the time for which the coolant supply unit 5 is subjected to the condensed water increasing treatment reaches a predetermined time, or when the water level increases and reaches the target water level. The configuration for determining that the conditions are satisfied has been described as an example. However, the conditions for increasing the condensed water are not limited to those described above, and various conditions can be adopted.

尚、上記実施形態（別実施形態を含む、以下同じ）で開示される構成は、矛盾が生じない限り、他の実施形態で開示される構成と組み合わせて適用することが可能であり、また、本明細書において開示された実施形態は例示であって、本発明の実施形態はこれに限定されず、本発明の目的を逸脱しない範囲内で適宜改変することが可能である。 It should be noted that the configuration disclosed in the above embodiment (including another embodiment, the same shall apply hereinafter) can be applied in combination with the configuration disclosed in other embodiments as long as there is no contradiction. The embodiments disclosed in the present specification are examples, and the embodiments of the present invention are not limited thereto, and can be appropriately modified without departing from the object of the present invention.

本発明は、例えば燃料電池システムに利用することができる。 The present invention can be used, for example, in a fuel cell system.

１燃料電池
２熱交換器
２１循環路
２２ポンプ（流量調節部）
２３放熱器
２４温度センサ（凝縮水情報取得部）
２５排ガス配管
３貯湯タンク
３３補給水路
３４排湯路
４水タンク
４４水位検出器（凝縮水情報取得部）
５冷却液供給部（凝縮水発生量調節部）
６冷却器（凝縮水発生量調節部） 1 Fuel cell 2 Heat exchanger 21 Circulation path 22 Pump (flow control unit)
23 Heat sink 24 Temperature sensor (condensed water information acquisition unit)
25 Exhaust gas piping 3 Hot water storage tank 33 Replenishment water channel 34 Hot water drainage channel 4 Water tank 44 Water level detector (condensed water information acquisition unit)
5 Coolant supply unit (condensed water generation amount adjustment unit)
6 Cooler (condensed water generation amount adjustment unit)

Claims

A fuel cell equipped with a reformer that steam reforms raw fuel to generate fuel gas and reacts the fuel gas and oxygen gas to generate power.
A combustion part that burns the fuel components remaining in the fuel gas used for the power generation reaction to generate exhaust gas,
A heat exchanger that recovers the heat of the exhaust gas discharged from the combustion unit, and
A water tank that recovers condensed water generated from the exhaust gas by heat recovery by the heat exchanger, and
A water supply path capable of supplying the condensed water stored in the water tank to the reformer, and
A hot water storage tank for storing hot water and
The condensed water information related to the amount of condensed water generated from the exhaust gas is the inflow hot water temperature, which is the temperature of the hot water supplied from the hot water storage tank and flowing into the heat exchanger, and the amount of water stored in the water tank. Condensed water information acquisition department to acquire the amount of stored water,
A condensed water generation amount adjusting unit that can adjust the amount of condensed water generated from the exhaust gas,
When the condensate water information satisfies a predetermined condensate water decrease condition indicating that the amount of condensate water tends to decrease, the inflow hot water temperature rises to the set temperature, and the water storage amount is the set lower limit water level. When the amount of condensed water information decreases to the specified time, the time required for the condensed water generation amount adjusting unit to perform the condensed water increasing treatment of supplying the cooling liquid to the heat exchanger is set to the predetermined time. The condensed water increasing treatment for increasing the amount of condensed water that can be recovered from the exhaust gas per unit time is performed on the condensed water generation amount adjusting unit until the amount of stored water reaches or the amount of stored water increases to reach the target amount of water. Equipped with an operation control unit
A circulation path for circulating hot water between the hot water storage tank and the heat exchanger is provided.
As the condensed water generation amount adjusting unit, the heat exchanger is provided with a cooling liquid supply unit capable of supplying the cooling liquid having a temperature lower than that of the hot water in the hot water storage tank.
The operation control unit can switch the heat exchanger between a hot water utilization state in which heat exchange between the exhaust gas and the hot water is performed and a coolant utilization state in which heat exchange between the exhaust gas and the coolant is possible. There is a fuel cell system in which the heat exchanger is put into the state of using the coolant and the coolant supply unit supplies the coolant to the heat exchanger as the treatment for increasing the condensed water.

A fuel cell equipped with a reformer that steam reforms raw fuel to generate fuel gas and reacts the fuel gas and oxygen gas to generate power.
A combustion part that burns the fuel components remaining in the fuel gas used for the power generation reaction to generate exhaust gas,
A heat exchanger that recovers the heat of the exhaust gas discharged from the combustion unit, and
A water tank that recovers condensed water generated from the exhaust gas by heat recovery by the heat exchanger, and
A water supply path capable of supplying the condensed water stored in the water tank to the reformer, and
A hot water storage tank for storing hot water and
The condensed water information related to the amount of condensed water generated from the exhaust gas is the inflow hot water temperature, which is the temperature of the hot water supplied from the hot water storage tank and flowing into the heat exchanger, and the amount of water stored in the water tank. Condensed water information acquisition department to acquire the amount of stored water,
A condensed water generation amount adjusting unit that can adjust the amount of condensed water generated from the exhaust gas,
When the condensate water information satisfies a predetermined condensate water decrease condition indicating that the amount of condensate water tends to decrease, the inflow hot water temperature rises to the set temperature, and the water storage amount is the set lower limit water level. When the amount of condensed water information decreases to the specified time, the time required for the condensed water generation amount adjusting unit to perform the condensed water increasing treatment of supplying the cooling liquid to the heat exchanger is set to the predetermined time. The condensed water increasing treatment for increasing the amount of condensed water that can be recovered from the exhaust gas per unit time is performed on the condensed water generation amount adjusting unit until the amount of stored water reaches or the amount of stored water increases to reach the target amount of water. Equipped with an operation control unit
An exhaust gas pipe for supplying the exhaust gas from the fuel cell to the heat exchanger is provided.
As the condensed water generation amount adjusting unit, a cooler capable of cooling the exhaust gas pipe and adjusting the heat radiation state from the exhaust gas via the exhaust gas pipe is provided.
The operation control unit is a fuel cell system that operates the cooler as the condensed water increasing process.

A fuel cell equipped with a reformer that steam reforms raw fuel to generate fuel gas and reacts the fuel gas and oxygen gas to generate power.
A combustion part that burns the fuel components remaining in the fuel gas used for the power generation reaction to generate exhaust gas,
A heat exchanger that recovers the heat of the exhaust gas discharged from the combustion unit, and
A water tank that recovers condensed water generated from the exhaust gas by heat recovery by the heat exchanger, and
A water supply path capable of supplying the condensed water stored in the water tank to the reformer, and
A hot water storage tank for storing hot water and
The condensed water information related to the amount of condensed water generated from the exhaust gas is the inflow hot water temperature, which is the temperature of the hot water supplied from the hot water storage tank and flowing into the heat exchanger, and the amount of water stored in the water tank. Condensed water information acquisition department to acquire the amount of stored water,
A condensed water generation amount adjusting unit that can adjust the amount of condensed water generated from the exhaust gas,
When the condensate water information satisfies a predetermined condensate water decrease condition indicating that the amount of condensate water tends to decrease, the inflow hot water temperature rises to the set temperature, and the water storage amount is the set lower limit water level. When the amount of condensed water information decreases to the specified time, the time required for the condensed water generation amount adjusting unit to perform the condensed water increasing treatment of supplying the cooling liquid to the heat exchanger is set to the predetermined time. The condensed water increasing treatment for increasing the amount of condensed water that can be recovered from the exhaust gas per unit time is performed on the condensed water generation amount adjusting unit until the amount of stored water reaches or the amount of stored water increases to reach the target amount of water. Equipped with an operation control unit
A circulation path for circulating hot water between the hot water storage tank and the heat exchanger is provided.
The heat exchanger can exchange heat between the exhaust gas and the hot water.
As the condensed water generation amount adjusting unit, a radiator for dissipating hot water flowing through the circulation path is provided on the upstream side of the heat exchanger.
When the condensed water information does not satisfy the condensed water reduction condition, the operation control unit operates the radiator at a predetermined operation amount when the temperature of the hot water flowing into the heat exchanger exceeds a predetermined temperature. A fuel cell system that operates the radiator at an operating amount exceeding the predetermined operating amount as the condensed water increasing process when the condensed water information satisfies the condensed water decreasing condition.

A circulation path for circulating hot water between the hot water storage tank and the heat exchanger is provided.
The fuel cell system according to claim 2 , wherein the heat exchanger is capable of heat exchange between the exhaust gas and the hot water.

A circulation path is provided for supplying hot water taken out from the lower part of the hot water storage tank to the heat exchanger and returning the hot water flowing through the heat exchanger to the upper part of the hot water storage tank.
The heat exchanger can exchange heat between the exhaust gas and the hot water.
From the hot water discharged from the hot water drain to the hot water storage tank via the hot water drainage channel for discharging hot water from the hot water storage tank and the make-up water channel connected to the lower part of the hot water storage tank as the condensed water generation amount adjusting unit. Equipped with a make-up water supply unit that can supply low-temperature make-up water,
As the condensed water increasing process, the operation control unit performs a hot water discharge operation of discharging hot water from the hot water storage tank through the hot water drainage channel and supplying make-up water from the make-up water supply unit to the hot water storage tank. The fuel cell system according to any one of claims 1 to 4.

A circulation path for circulating hot water between the hot water storage tank and the heat exchanger is provided.
The heat exchanger can exchange heat between the exhaust gas and the hot water.
As the condensed water generation amount adjusting unit, a flow rate adjusting unit capable of adjusting the flow rate of hot water flowing through the circulation path per unit time is provided.
The fuel cell system according to any one of claims 1 to 5, wherein the operation control unit increases the flow rate of hot water flowing through the circulation path per unit time as the condensed water increasing process.