JP4195974B2

JP4195974B2 - Fuel cell cogeneration system

Info

Publication number: JP4195974B2
Application number: JP2002293855A
Authority: JP
Inventors: 伸二宮内; 哲也上田; 精米田; 雅夫山本; 彰成中村
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2002-10-07
Filing date: 2002-10-07
Publication date: 2008-12-17
Anticipated expiration: 2022-10-07
Also published as: JP2004127841A

Description

【０００１】
【発明の属する技術分野】
本発明は、燃料電池の排熱回収により湯水を貯える貯湯タンクと貯湯水を追焚する追焚加熱手段とにより給湯利用する装置に関する。
【０００２】
【従来の技術】
従来、燃料電池コージェネレーションシステムにおける給湯および熱利用装置は、図７に示されるものが一般的であった。この装置は図７に示すように、燃料電池１が、燃料ガス供給弁２より燃料ガスを供給され、発電運転を行い、発電時の排熱を排熱回収配管３を介して、貯湯タンク４に熱回収するように接続されている。貯湯タンク４に蓄えられた湯水は出湯配管５を介して追焚加熱手段６に送られ、給湯栓７の給湯需要設定水温より貯湯水温が低い場合に、追焚加熱され、給湯需要設定温度に維持されながら給湯配管８により給湯栓７に供給される。燃料電池１は、燃料電池外装９、貯湯タンク４は貯湯タンク外装１０、追焚加熱手段６は追焚加熱手段外装１１により、それぞれ個別に外装され、各機器を直列に接続されている（例えば、特許文献１、２、または３参照）。
【０００３】
【特許文献１】
特開平１１−９７０４４号公報
【特許文献２】
特開２００２―５６８６７号公報
【特許文献３】
特開２００２―７５３９２号公報
【０００４】
【発明が解決しようとする課題】
しかしながら、従来の装置においては、燃料電池と貯湯槽と追焚加熱手段（追焚用給湯機）を、それぞれ独立して直列に設置するため、家庭用コージェネ機器として広い設置場所を必要とし、設置性が困難であった。
【０００５】
また、各機器は配管を引き回して接続するため放熱ロスを生じ易く、経済性も悪かった。燃料電池の改質器バーナ加熱部と追焚加熱手段が個別設置の場合、燃料電池の改質器バーナ加熱部と追焚加熱手段それぞれに排気ガス通路、排気口を設けるため、排気部の容積が大きくなり、装置も大型化するという課題を有していた。
【０００６】
【課題を解決するための手段】
上記課題を解決するため、本発明の燃料電池コージェネレーションシステムは、燃料ガスと酸化剤ガスとを反応させて発電を行う燃料電池と、前記燃料電池の発電時の排熱を回収する貯湯タンクと、前記貯湯タンクの湯水を追焚加熱する追焚加熱手段とを有し、前記追焚加熱手段および前記燃料電池は前記貯湯タンク側部に配置され、前記追焚加熱手段は、前記燃料電池の上部に配置されていることを特徴とする。
【０００７】
また、本発明は、少なくとも前記貯湯タンクおよび追焚加熱手段が、断熱材を有する１つの外装内に収納されていると有効である。
【０００８】
また、本発明は、前記貯湯タンクが、前記貯湯タンクの上部より貯湯されていく積層式であると有効である。
【０００９】
また、本発明は、前記燃料ガスを生成する改質器を加熱するバーナ加熱部および前記追焚加熱手段の少なくともいずれか一方の排ガスの熱を回収する排ガス熱交換器と、前記燃料電池の冷却水中の熱を回収する冷却水熱交換器とを備え、貯湯タンクへの熱回収は、（１）前記排ガス熱交換器による熱回収（２）前記冷却水熱交換器による熱回収の順に行うと有効である。
【００１０】
また、本発明は、前記改質器バーナ加熱部の排ガス経路と前記追焚加熱手段の排ガス経路とが結合し、一つの排ガス熱交換器で排ガス熱回収を行うと有効である。
【００１１】
また、本発明は、前記追焚加熱手段非動作時に、前記追焚加熱手段の排ガス経路の排ガス熱交換器をバイパスするバイパス回路を備えると有効である。
【００１２】
また、本発明は、前記排ガス熱交換器の下流、かつ前記冷却水熱交換器の上流に前記燃料電池からの燃料排ガス中の熱を熱回収する燃料排ガス熱交換器および前記燃料電池からの酸化剤排ガス中の熱を熱回収する酸化剤排ガス熱交換器の少なくともいずれか一方を備えると有効である。
【００１３】
また、本発明は、前記貯湯タンクから前記冷却水熱交換器までの排熱回収路と前記貯湯タンクから前記排ガス熱交換器までの排熱回収路とをバイパスする貯湯タンクバイパス回路と、冷却水循環経路上に前記冷却水熱交換器をバイパスするバイパス回路と、前記バイパス回路上に加熱手段とを備え、前記燃料電池起動時に、前記貯湯タンクバイパス回路に切り換え、前記冷却水熱交換器を介して前記加熱手段による回収熱を利用して冷却水を昇温させると有効である。
【００１４】
【発明の実施の形態】
以下、本発明の実施の形態を、図面を参照して説明する。
【００１５】
（実施の形態１）
図１は本発明の実施の形態１における燃料電池コージェネレーションシステムのブロック構成図である。図１において、図７で示した従来の燃料電池コージェネレーションシステムと同じ機能を有するものについては、同一符号を付与しており、それらの機能の詳細は、図７のものに準ずるものとして説明を省略する。
【００１６】
図１において、燃料電池１の上部に追焚加熱手段６を配置し、原料ガス供給を原料ガス供給弁２より、燃料電池１と追焚加熱手段６に分岐配管接続している。貯湯タンク４への給水は給水弁１２より、貯湯タンク４の下部に供給されるように接続されている。燃料電池１の発電反応に伴う排熱回収は排熱回収配管３により貯湯タンク４の下部より貯湯タンク４内下層の水を燃料電池１に取り入れ、排熱回収後の湯を燃料電池１から貯湯タンク４の上部へ戻すように接続されている。貯湯タンク４からの湯水は出湯配管５を介し追焚加熱手段６へ供給されるように接続されており、貯湯タンク４上部に近接した追焚加熱手段６の給水口１３へ短回路配管にて接続されている。追焚加熱手段６からの追焚された湯は給湯配管８を経由して給湯栓７より供給されるように接続されている。そして、これら、燃料電池１、貯湯タンク４、追焚加熱手段６、排熱回収配管３、出湯配管５等々が外装１４の中で、各配管を最短でかつ、断熱材（図示せず）を共有し、一体化されて接続されている。
【００１７】
なお、上述の構成では燃料電池の排熱回収を燃料電池内に貯湯タンクの水を取り入れ排熱回収を行っていたが、燃料電池内を冷却する冷却水と貯湯タンクの水を熱交換器を介して排熱回収する構成であっても構わない。
【００１８】
次に、動作、作用について説明する。
【００１９】
まず、燃料電池起動、発電時には、燃料電池１の運転に適した温度（７０〜８０℃）に昇温されるため、燃料電池１と断熱材を共有した追焚加熱手段６に燃料電池部分より余熱が上昇し、追焚加熱手段の入出口配管である出湯配管や給湯配管が保温され、冷えにくくなり、配管内の湯の温度低下が緩和される。
【００２０】
また、燃料電池と貯湯タンクと追焚加熱手段とを一つの外装内で接続構成し、かつ貯湯タンクが、上部から暖かい湯が貯湯される積層貯湯方式であり、給湯は貯湯タンク上部から湯を取り出し行うため、燃料電池と貯湯タンク間、貯湯タンクと追焚加熱手段間の給湯配管が最短回路で結ばれ、小型化が図れ、また、燃料電池と貯湯タンクと追焚加熱手段とを断熱材を共用化しているため、排熱ロスが低減できる。
【００２１】
さらに、燃料電池１内部には、燃料ガス供給手段としての改質器（図示せず）や酸化剤ガス供給手段としてのブロアファン（図示せず）、加湿器さらに燃料ガスと酸化剤ガスとを反応させて発電を行う燃料電池本体（図示ぜず）等の重量部品を搭載しており、この燃料電池を下部に、熱交換器、バーナ等の比較的軽量部品を搭載した追焚加熱手段６を燃料電池１の上部に配置したことにより、外装１４内の機器全体の設置安定性が良い。また、燃料電池１の重量部品の部品交換等が発生した場合、高い位置から重量部品を引き下ろす必要が無く、サービス、メンテ性に優れる。
【００２２】
（実施の形態２）
図２は本発明の実施の形態２における燃料電池コージェネレーションシステムのブロック構成図である。
【００２３】
図２において、図１で示した実施の形態１の燃料電池コージェネレーションシステムと同じ機能を有するものについては、同一符号を付与しており、それらの機能の詳細は、図１のものに準ずるものとして説明を省略する。
【００２４】
図２において、２０は燃料電池本体であり、燃料ガス供給手段２１は天然ガスなどの原料ガスを、一方は燃焼ガス供給弁２２を介して改質器バーナ加熱部２３へ、もう一方は原料ガス供給弁２４を介して改質器２５へ供給し、加熱・水蒸気改質し、水素を主成分とする燃料ガスを生成して燃料電池本体２０に供給するように接続されている。
【００２５】
燃料ガス供給手段２１には、改質器バーナ加熱部２３から第１の排ガス経路２６に至る間に第１の排ガス熱交換器２７が備えられている。
【００２６】
２８は空気供給装置としてのブロアファンであり、酸化剤の空気を燃料電池本体２０に供給する。このとき、酸化側加湿器２９で供給空気を加湿する。燃料電池本体２０には、冷却水を送って冷却する冷却水配管３０と、冷却水配管内の水を循環させる冷却水ポンプ３１とを備えている。
【００２７】
また、発電時には、冷却水熱交換器３２および循環ポンプ３３により燃料電池本体２０の発電による排熱を燃料電池内排熱回収配管３４から排熱回収配管３を経由して貯湯タンク４へ排熱回収するよう接続されている。そして燃料電池本体２０を含む、点線内１がいわゆる燃料電池である。
【００２８】
貯湯タンク４は、貯湯タンク４下部の給水口３５より給水し、一部が給水配管３６に分岐され貯湯タンク４下部の給湯口３７より出湯配管５を介して給湯し、混合弁３８に供給するように接続されている。
【００２９】
制御手段３９は、貯湯タンク４からの湯と水をサーミスタ等の混合温度検知手段４０により給湯需要設定温度なるように混合弁３８の混合比を制御し、かつ貯湯温度検知手段（サーミスタ等）４１により貯湯タンク４の貯湯温度が高温（７０〜８０℃）一定になるように循環ポンプ３３の循環流量を制御するように接続されている。さらに、燃料ガス供給手段２１への供給ガスを燃焼ガス供給弁２２，原料ガス供給弁２４により制御し、空気供給装置２８からの供給空気量を制御し、燃料電池本体２０の冷却水流量を冷却水ポンプ３１を介して制御するように接続されている。
【００３０】
混合弁３８の下流側には、追焚加熱部４２により追焚加熱された湯が給湯配管８を経由して給湯栓４３から出湯されるように配管されている。追焚加熱部４２には、追焚加熱バーナ４４に原料ガスを供給する追焚原料ガス供給弁４５が接続されており、追焚加熱熱交換器４６から下流側の第２の排ガス経路４７にかけて第２の排ガス熱交換器４８が設置されている。また、制御手段３９は、追焚加熱温度検知手段（サーミスタ等）４９により貯湯タンク４内の貯湯温度が給湯需要設定温度以下の場合、給湯需要設定温度になるように追焚加熱バーナ４４の燃焼量を追焚原料ガス供給弁４５のガス量を調整し行うように接続されている。そして追焚加熱部４２を含む、点線内６が追焚加熱手段である。そして、これら、燃料電池１、貯湯タンク４、追焚加熱手段６、排熱回収配管３、出湯配管５等々が外装１４の中で、各配管を最短でかつ、断熱材（図示せず）を共有し、一体化されて接続されている。
【００３１】
次に、動作、作用について説明する。
【００３２】
まず、燃料電池起動時には、制御手段３９により、燃料ガス供給手段２１の改質器バーナ加熱部２３の燃焼量を制御し、改質器２５を加熱するとともに改質器２５の加熱により水素を主成分とする燃料ガスが所定の一酸化炭素濃度（約１０〜２０ｐｐｍ）以下になれば燃料電池本体２０に供給する。
【００３３】
次に、燃料電池発電時には、制御手段３９により、まず、燃料ガス供給手段２１の改質器バーナ加熱部２３の燃焼による排ガスから第１の排ガス熱交換器２７を介して貯湯タンク４下部から取り出された水等の熱輸送媒体が流れる燃料電池内排熱回収配管３４側へ熱回収する。次に、燃料ガス供給手段２１の改質器２５から供給された水素を主成分とする燃料ガスと空気供給装置２８から供給された空気（酸素）とにより燃料電池本体２０の発電反応に伴う排熱を冷却水ポンプ３１を動作させ、冷却水熱交換器３２を介して燃料電池内排熱回収配管３４側へ熱回収する。制御手段３９は、第１の排ガス熱交換器２７、冷却水熱交換器３２の順に排熱回収し、貯湯温度検知手段４１により貯湯タンク４の貯湯温度が高温（７０〜８０℃）一定になるように循環ポンプ３３の循環流量を制御する。
【００３４】
貯湯タンク４が貯湯量が満タンになれば、循環ポンプを停止させ燃料電池内排熱回収配管３４と排熱回収配管３を介した排熱回収を完了する。
【００３５】
次に、貯湯タンク４の貯湯量が十分なときには、給湯栓４３による給湯利用時に混合温度検知手段４０での混合温度検出値が給湯需要設定温度よりも高いので追焚加熱部４２での追い焚き動作は不要であり、貯湯湯水は直接給湯栓４３側に供給される。
【００３６】
次に、貯湯タンク４の貯湯量が少なく不十分なときには、給湯栓４３による給湯利用時に混合温度検知手段４０での混合温度検出値が給湯需要設定温度よりも低くなった場合、追焚加熱部４２での追い焚き動作が必要となり、制御手段３９は、追焚加熱温度検知手段４９により、給湯需要設定温度になるように追焚加熱バーナ４４の燃焼量を追焚原料ガス供給弁４５のガス量調節により調整する。
【００３７】
このとき、燃料電池本体２０が発電している場合には、制御手段３９により、まず、燃料ガス供給手段２１の改質器バーナ加熱部２３の燃焼による排ガスから第１の排ガス熱交換器２７を介して貯湯タンク４の燃料電池内排熱回収配管３４側へ熱回収され、さらに、追焚加熱部４２の追焚加熱バーナ加熱部４４の燃焼による排ガスから第２の排ガス熱交換器４８を介して貯湯タンク４の燃料電池内排熱回収配管３４側へ排ガスの熱回収が行われる。次に、水素を主成分とする燃料ガスと空気（酸素）とにより燃料電池本体２０の発電反応に伴う排熱を冷却水ポンプ３１を動作させ、冷却水熱交換器３２を介して燃料電池内排熱回収配管３４側へ熱回収する。制御手段３９は、第１の排ガス熱交換器２７、第２の排ガス熱交換器４８、冷却水熱交換器３２の順に排熱回収し、貯湯温度検知手段４１により貯湯タンク４の貯湯温度が高温（７０〜８０℃）一定になるように循環ポンプ３３の循環流量を制御する。
【００３８】
よって、燃料電池本体２０発電時、追焚加熱部４２の追焚加熱時には、貯湯タンク４への排熱回収量が冷却水熱交換器３２による排熱回収量に、排ガス経路の第１の排ガス熱交換器２７および／または第２の排ガス熱交換器４８による排熱回収配量が付加されるため熱回収効率が向上する。
【００３９】
（実施の形態３）
図３は、本発明の実施の形態３の燃料電池コージェネレーションシステムのブロック構成図である。
【００４０】
実施の形態２と異なる点は、燃料ガス供給手段２１の改質器バーナ加熱部２３の排ガス経路と追焚加熱部４２の排ガス経路を結合した統合排ガス経路５０と、この統合排ガス経路５０内の排ガスの熱回収を行う統合排ガス熱交換器５１を設けた点である。
【００４１】
なお、実施の形態１、２と同一符号のものは同一構造を有し、説明は省略する。
【００４２】
次に、動作、作用について説明する。
【００４３】
まず、燃料電池起動時には、制御手段３９により、燃料ガス供給手段２１の改質器バーナ加熱部２３の燃焼量を制御し、改質器２５を加熱するとともに改質器２５の加熱により水素を主成分とする燃料ガスが所定の一酸化炭素濃度（約１０〜２０ｐｐｍ）以下になれば燃料電池本体２０に供給する。
【００４４】
次に、燃料電池発電時には、制御手段３９により、まず、燃料ガス供給手段２１の改質器バーナ加熱部２３の燃焼による排ガスから統合排ガス熱交換器５１を介して燃料電池内排熱回収配管３４側へ熱回収する。次に、燃料ガス供給手段２１の改質器２５から供給された水素を主成分とする燃料ガスと空気供給装置２８から供給された空気（酸素）とにより燃料電池本体２０の発電反応に伴う排熱を冷却水ポンプ３１を動作させ、冷却水熱交換器３２を介して燃料電池内排熱回収配管３４側へ熱回収する。制御手段３９は、統合排ガス熱交換器５１、冷却水熱交換器３２の順に排熱回収し、貯湯温度検知手段４１により貯湯タンク４の貯湯温度が高温（７０〜８０℃）一定になるように循環ポンプ３３の循環流量を制御する。
【００４５】
貯湯タンク４が貯湯量が満タンになれば、循環ポンプを停止させ燃料電池内排熱回収配管３４と排熱回収配管３を介した排熱回収を完了する。
【００４６】
貯湯タンク４の貯湯量が少なく不十分なときには、実施の形態１と同様に追焚加熱部４２を介して、追焚加熱温度検知手段４９により、給湯需要設定温度になるように追焚加熱バーナ４４の燃焼量を調整する。
【００４７】
よって、燃料電池本体２０発電時、追焚加熱部４２の追焚加熱時には、貯湯タンク４への排熱回収が統合排ガス経路５０の統合排ガス熱交換器５１による排熱回収と冷却水熱交換器３２による発電反応の排熱回収が付加されるため熱回収効率が向上する。さらに、燃料電池本体２０の改質器バーナ加熱部２３の排ガス経路と追焚加熱部４２の排ガス経路を結合し、一つの排ガス熱交換器で排ガス熱回収を行うようにしたことにより、燃料電池コージェネレーションシステムとしての低コスト化、小型化、高効率化が図れる。
【００４８】
（実施の形態４）
図４は、本発明の実施の形態４の燃料電池コージェネレーションシステムのブロック構成図である。
【００４９】
実施の形態２と異なる点は、追焚加熱部４２の排ガス経路４７の第２の排ガス熱交換器４８をバイパスさせるバイパス回路５２とバイパス回路５２と第２の排ガス熱交換器４８を切り換えるバイパス弁５３を設けた点である。
【００５０】
なお、実施の形態１と同一符号のものは同一構造を有し、説明は省略する。
【００５１】
次に、動作、作用について説明する。
【００５２】
燃料電池発電時には、制御手段３９により、まず、燃料ガス供給手段２１の改質器バーナ加熱部２３の燃焼による排ガスから第１の排ガス熱交換器２７を介して燃料電池内排熱回収配管３４側へ熱回収する。このとき、追焚加熱部４２が動作していなければ、バイパス弁５３を介してバイパス回路５２を経由して、追焚加熱部４２が動作していれば、第２の排ガス熱交換器４８を経由して熱回収する。次に、燃料ガス供給手段２１の改質器２５から供給された水素を主成分とする燃料ガスと空気供給装置２８から供給された空気（酸素）とにより燃料電池本体２０の発電反応に伴う排熱を冷却水ポンプ３１を動作させ、冷却水熱交換器３２を介して燃料電池内排熱回収配管３４側へ熱回収する。制御手段３９は、第１の排ガス熱交換器２７および／または第２の排ガス熱交換器４８、冷却水熱交換器３２の順に排熱回収し、貯湯温度検知手段４１により貯湯タンク４の貯湯温度が高温（７０〜８０℃）一定になるように循環ポンプ３３の循環流量を制御する。
【００５３】
貯湯タンク４が貯湯量が満タンになれば、循環ポンプを停止させ燃料電池内排熱回収配管３４、排熱回収配管３を介した排熱回収を完了する。
【００５４】
貯湯タンク４の貯湯量が少なく不十分なときには、実施の形態２と同様に追焚加熱部４２を介して、追焚加熱温度検知手段４９により、給湯需要設定温度になるように追焚加熱バーナ４４の燃焼量を調整する。
【００５５】
よって、燃料電池本体２０発電時、追焚加熱部４２が非動作時には、貯湯タンク４への排熱回収が第１の排ガス経路２７の第１の排ガス熱交換器２７による排熱回収と冷却水熱交換器３２による発電反応の排熱回収とにより行われ、追焚加熱部４２の第２の排ガス経路４７の第２の排ガス熱交換器４８を経由することなく行われるため排ガス熱交換器による放熱ロスをなくし、一層の高効率化が図れる。
【００５６】
（実施の形態５）
図５は、本発明の実施の形態５の燃料電池コージェネレーションシステムのブロック構成図である。
【００５７】
実施の形態２と異なる点は、燃料電池本体２０と化学反応した後の燃料排ガス中の熱を熱回収する燃料排ガス熱交換器５４を第２の排ガス熱交換器４８と冷却水熱交換器３２の間に配置した点である。
【００５８】
なお、実施の形態１と同一符号のものは同一構造を有し、説明は省略する。
【００５９】
次に、動作、作用について説明する。
【００６０】
燃料電池発電時には、制御手段３９により、まず、燃料ガス供給手段２１の改質器バーナ加熱部２３の燃焼による排ガスから第１の排ガス熱交換器２７を介して燃料電池内排熱回収配管３４側へ熱回収する。このとき、追焚加熱部４２が動作していれば、第２の排ガス熱交換器４８でさらに追焚加熱手段の排ガスの熱回収を行う。次に、燃料排ガス熱交換器５４を経由して、燃料電池本体２０と化学反応した後の燃料排ガス中の熱を熱回収する。さらに、燃料電池本体２０の発電反応に伴う排熱を冷却水ポンプ３１を動作させ、冷却水熱交換器３２を介して燃料電池内排熱回収配管３４側へ熱回収する。制御手段３９は、第１の排ガス熱交換器２７および第２の排ガス熱交換器４８、燃料排ガス熱交換器５４、冷却水熱交換器３２の順に排熱回収し、貯湯温度検知手段（サーミスタ）４１により貯湯タンク４の貯湯温度が高温（７０〜８０℃）一定になるように循環ポンプ３３の循環流量を制御する。
【００６１】
貯湯タンク４が貯湯量が満タンになれば、循環ポンプを停止させ燃料電池内排熱回収配管３４、排熱回収配管３を介した排熱回収を完了する。
【００６２】
貯湯タンク４の貯湯量が少なく不十分なときには、実施の形態２と同様に追焚加熱部４２を介して、追焚加熱温度検知手段４９により、給湯需要設定温度になるように追焚加熱バーナ４４の燃焼量を調整する。
【００６３】
よって、貯湯タンクへの熱回収を、燃料電池の改質器バーナ加熱部の排ガス熱交換器および／または追焚加熱手段の排ガス熱交換器による熱回収、次に燃料電池と化学反応した後の燃料排ガス中の熱を熱回収する燃料排ガス熱交換器、さらに燃料電池の発電時の冷却水循環による冷却水熱交換器を介した熱回収の順に行うことにより排気ガスと貯湯水の低温熱交換（ガス−水熱交換）から燃料電池の冷却水と貯湯水の高温熱交換（水−水熱交換）を順次行うことにより、燃料電池、追焚加熱手段の排熱回収効率が一段と向上する。
【００６４】
なお、本実施の形態では、燃料電池と化学反応した後の燃料排ガス中の熱を熱回収する燃料排ガス熱交換器を排ガス熱交換器と冷却水熱交換器の間に設ける構成としたが燃料電池と化学反応した後の酸化剤排ガス中の熱を熱回収する酸化剤排ガス熱交換器を設けた構成としても、同様の効果を有することは言うまでもない。
【００６５】
また、改質器バーナ加熱部の排ガス熱交換器および／または追焚加熱手段の排ガスについて熱交換器実施の形態２，３または４のような構成を採用しても同様の効果を有することは言うまでもない。
【００６６】
（実施の形態６）
図６は、本発明の実施の形態６の燃料電池コージェネレーションシステムのブロック構成図である。
【００６７】
実施の形態２と異なる点は、
冷却水配管３０の循環経路の冷却水熱交換器３２をバイパスさせる冷却水バイパス弁５５、バイパス回路中に燃料電池本体２０起動時に冷却水を加熱するためのヒータ等の加熱手段５６を備えている点。また、貯湯タンクへの回収熱をバイパスさせる貯湯タンクバイパス回路５７に切り換える貯湯タンクバイパス弁５８，５９を備えた点である。
【００６８】
なお、実施の形態２と同一符号のものは同一構造を有し、説明は省略する。
【００６９】
次に、動作、作用について説明する。
【００７０】
まず、燃料電池起動時には、制御手段３９により、燃料ガス供給手段２１の改質器バーナ加熱部２３の燃焼量を制御し、改質器２５を加熱するとともに改質器２５の加熱により水素を主成分とする燃料ガスが所定の一酸化炭素濃度（約１０〜２０ｐｐｍ）以下になれば燃料電池本体２０に供給する。
【００７１】
このとき、冷却水バイパス弁５５を加熱手段５６側にバイパスさせ、燃料電池本体２０の冷却水を加熱手段（ヒータ）５６により発電に適した温度になるように昇温させる。
【００７２】
さらに、貯湯タンクバイパス弁５８，５９を貯湯タンクバイパス回路５７側に切り換え改質器バーナ加熱部２３の燃焼による排ガス熱を第１の排ガス熱交換器２７を介して燃料電池内排熱回収配管３４側へ熱回収する。そして、循環ポンプ３３により燃料電池内排熱回収配管３４と貯湯タンクバイパス回路５７の閉回路を排熱循環させる。この排ガス熱交換器２７からの回収熱を冷却水熱交換器３２を介して冷却水配管３０側へ熱回収し、冷却水バイパス弁５５の弁開度を調節して、排ガス熱交換器２７からの回収熱と加熱手段（ヒータ）５６と両者の熱回収により燃料電池本体２０を加温する。
【００７３】
次に、燃料電池発電時には、制御手段３９により、まず、燃料ガス供給手段２１の改質器バーナ加熱部２３の燃焼による排ガスから第１の排ガス熱交換器を介して燃料電池内排熱回収配管３４側へ熱回収する。次に、冷却水バイパス弁を冷却水熱交換器側に通じ、燃料電池本体２０の発電反応に伴う排熱を冷却水ポンプ３１を動作させ、冷却水熱交換器３２を介して燃料電池内排熱回収配管３４側へ熱回収する。貯湯タンクバイパス弁５８，５９は、貯湯タンクバイパス回路５７側から貯湯タンク４への排熱回収側へ切り換える。制御手段３９は、第１の排ガス熱交換器２７、冷却水熱交換器３２の順に排熱回収し、貯湯温度検知手段（サーミスタ）４１により貯湯タンク４の貯湯温度が高温（７０〜８０℃）一定になるように循環ポンプ３３の循環流量を制御する。
【００７４】
よって、燃料電池起動時は、冷却水循環経路の冷却水熱交換器３２をバイパス比を調節し、排ガス熱交換器２７からの回収熱と加熱手段（ヒータ）５６と両者の熱回収により冷却水を昇温させ、燃料電池を加温するようにしたことにより、燃料電池起動時に、燃料電池起動のための冷却水の昇温が迅速になり、短時間起動が可能となり、使い勝手がさらに向上する。
【００７５】
なお、改質器バーナ加熱部の排ガス熱交換器および／または追焚加熱手段の排ガスについて熱交換器実施の形態２、３、４または５のような構成を採用しても同様の効果を有することは言うまでもない。
【００７６】
【発明の効果】
以上の説明から明らかなように、本発明の燃料電池コージェネレーションシステムによれば、次の効果が得られる。
【００７７】
１）貯湯タンク側部に燃料電池と追焚加熱手段を近接し、燃料ガス供給手段としての改質器や酸化剤ガス供給手段としてのブロアファン、加湿器さらに燃料ガスと酸化剤ガスとを反応させて発電を行う燃料電池本体等の重量部品を搭載した燃料電池を下部に、熱交換器、バーナ等の比較的軽量部品を搭載した追焚加熱手段を燃料電池の上部に配置したことにより、機器全体の設置安定性に優れ、燃料電池本体等の重量部品の部品交換等のサービス、メンテ性が良くできる。
【００７８】
２）燃料電池を追焚加熱手段の下部に設けおり、燃料電池の運転温度が７０〜８０℃と高温であるため、燃料電池運転時には燃料電池部分より余熱が上昇し、追焚加熱手段の入出口配管である出湯配管や給湯配管が保温され、冷えにくくなり、給湯機固有の課題である出湯の前後の配管内の湯が冷やされる現象（いわゆる、前冷え、冷水サンドイッチ現象）が緩和される。
【００７９】
３）燃料電池と貯湯タンクと追焚加熱手段とを一つの外装内で接続構成することにより、燃料電池と貯湯タンク間、貯湯タンクと追焚加熱手段間の給湯配管が簡略化、最短化でき、燃料電池と貯湯タンクと追焚加熱手段とを断熱材など共用化できるため、一層の小型化と排熱ロス低減による高効率化が図れる。
【００８０】
４）燃料電池の改質器バーナ加熱部の排ガスと追焚加熱手段の排ガスの熱回収をすることにより排熱回収効率を高められ、かつ排ガス熱交換器による熱回収、次に前記燃料電池本体の発電時排熱の冷却水循環による冷却水熱交換器を介した熱回収の順に行うことにより、排気ガスの潜熱回収の後に、燃料電池の冷却水の熱交換という効率良い排熱回収が実現でき、高効率なコージェネレーション機器を提供できる。
【００８１】
５）燃料電池の改質器バーナ加熱部の排ガス経路と追焚加熱手段の排ガス経路を結合し、一つの排ガス熱交換器で排ガス熱回収を行うようにしたことにより、低コスト化、小型化、高効率化が図れる。
【００８２】
６）追焚加熱手段非動作時は、追焚加熱手段の排ガス経路の排ガス熱交換器をバイパスさせることにより、追焚加熱手段の排ガス経路の排ガス熱交換器を経由することことによる放熱ロスをなくし、一層の高効率化が図れる。
【００８３】
７）貯湯タンクへの熱回収を、燃料電池の改質器バーナ加熱部の排ガス熱交換器および／または追焚加熱手段の排ガス熱交換器による熱回収、次に燃料電池と化学反応した後の燃料排ガス中の熱を熱回収する燃料排ガス熱交換器および／または燃料電池と化学反応した後の酸化剤排ガス中の熱を熱回収する酸化剤排ガス熱交換器、さらに燃料電池の発電時の冷却水循環による冷却水熱交換器を介した熱回収の順に行うことにより排気ガスと貯湯水の低温熱交換（ガス−水熱交換）から燃料電池の冷却水と貯湯水の高温熱交換（水−水熱交換）を順次行うことにより、燃料電池、追焚加熱手段の排熱回収効率が一段と向上する。
【００８４】
８）燃料電池起動時は、冷却水循環経路の冷却水熱交換器３２をバイパス比を調節し、排ガス熱交換器２７からの回収熱と加熱手段（ヒータ）５７と両者の熱回収により冷却水を昇温させ、燃料電池を加温するようにしたことにより、燃料電池起動時に、燃料電池起動のための冷却水の昇温が迅速になり、短時間起動が可能となり、使い勝手が向上する。
【図面の簡単な説明】
【図１】本発明の実施の形態１の燃料電池コージェネレーションシステムのブロック構成図
【図２】本発明の実施の形態２の燃料電池コージェネレーションシステムのブロック構成図
【図３】本発明の実施の形態３の燃料電池コージェネレーションシステムのブロック構成図
【図４】本発明の実施の形態４の燃料電池コージェネレーションシステムのブロック構成図
【図５】本発明の実施の形態５の燃料電池コージェネレーションシステムのブロック構成図
【図６】本発明の実施の形態６の燃料電池コージェネレーションシステムのブロック構成図
【図７】従来の排熱回収装置のブロック構成図
【符号の説明】
１燃料電池
３排熱回収配管
４貯湯タンク
５出湯配管
６追焚加熱手段
１４外装
２３改質器バーナ加熱部
２７第１の排ガス熱交換器
３２冷却水熱交換器
４８第２の排ガス熱交換器
５１統合排ガス熱交換器
５２，５７バイパス回路
５４燃焼排ガス熱交換器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus that uses hot water supply by a hot water storage tank that stores hot water by recovering exhaust heat of a fuel cell and a reheating heater that tracks the stored hot water.
[0002]
[Prior art]
Conventionally, a hot water supply and heat utilization apparatus in a fuel cell cogeneration system is generally shown in FIG. In this apparatus, as shown in FIG. 7, the fuel cell 1 is supplied with fuel gas from a fuel gas supply valve 2, performs power generation operation, and exhaust heat generated during power generation is transferred to a hot water storage tank 4 via an exhaust heat recovery pipe 3. Connected to heat recovery. Hot water stored in the hot water storage tank 4 is sent to the reheating heating means 6 through the hot water supply pipe 5, and when the stored hot water temperature is lower than the hot water supply demand setting water temperature of the hot water tap 7, it is reheated and reaches the hot water supply demand setting temperature. While being maintained, the hot water supply pipe 8 supplies the hot water tap 7. The fuel cell 1 is individually packaged by a fuel cell exterior 9, the hot water storage tank 4 is by a hot water storage tank exterior 10, and the memorial heating means 6 is individually memorized by an amendment heating means exterior 11, and the respective devices are connected in series (for example, , Patent Document 1, 2, or 3).
[0003]
[Patent Document 1]
JP-A-11-97044
[Patent Document 2]
JP 2002-56867 A
[Patent Document 3]
JP 2002-75392 A
[0004]
[Problems to be solved by the invention]
However, in the conventional apparatus, since the fuel cell, hot water tank, and additional heating means (hot water heater for additional heating) are installed independently in series, a large installation space is required and installed as a household cogeneration device. The sex was difficult.
[0005]
In addition, since each device is connected by drawing piping, heat loss is likely to occur, and the economy is also poor. When the reformer burner heating part and the additional heating means of the fuel cell are installed separately, the exhaust gas passage and the exhaust port are provided in the reformer burner heating part and the additional heating means of the fuel cell, respectively. However, there is a problem that the size of the apparatus is increased.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, a fuel cell cogeneration system according to the present invention includes a fuel cell that generates power by reacting a fuel gas and an oxidant gas, and a hot water storage tank that recovers exhaust heat during power generation of the fuel cell. And a reheating means for reheating the hot water in the hot water storage tank, the reheating heating means and the fuel cell are arranged on the side of the hot water storage tank, and the reheating heating means is connected to the fuel cell. It is arranged at the top.
[0007]
In addition, the present invention is effective when at least the hot water storage tank and the reheating means are accommodated in one exterior having a heat insulating material.
[0008]
Further, the present invention is effective when the hot water storage tank is a stacked type in which hot water is stored from the upper part of the hot water storage tank.
[0009]
The present invention also provides an exhaust gas heat exchanger that recovers heat of exhaust gas of at least one of a burner heating section that heats the reformer that generates the fuel gas and the additional heating means, and cooling of the fuel cell. A cooling water heat exchanger that recovers heat in the water, and heat recovery to the hot water storage tank is performed in the order of (1) heat recovery by the exhaust gas heat exchanger (2) heat recovery by the cooling water heat exchanger It is valid.
[0010]
Further, the present invention is effective when the exhaust gas path of the reformer burner heating unit and the exhaust gas path of the additional heating means are combined and exhaust gas heat recovery is performed with one exhaust gas heat exchanger.
[0011]
Further, the present invention is effective when a bypass circuit for bypassing the exhaust gas heat exchanger in the exhaust gas path of the additional heating means is provided when the additional heating means is not operating.
[0012]
The present invention also provides a fuel exhaust gas heat exchanger that recovers heat in the fuel exhaust gas from the fuel cell downstream of the exhaust gas heat exchanger and upstream of the cooling water heat exchanger, and an oxidation from the fuel cell. It is effective to provide at least one of an oxidant exhaust gas heat exchanger that recovers heat in the exhaust gas.
[0013]
The present invention also provides a hot water tank bypass circuit that bypasses an exhaust heat recovery path from the hot water storage tank to the cooling water heat exchanger and an exhaust heat recovery path from the hot water storage tank to the exhaust gas heat exchanger, and a cooling water circulation A bypass circuit for bypassing the cooling water heat exchanger on the path, and heating means on the bypass circuit, and switching to the hot water tank bypass circuit when the fuel cell is started, via the cooling water heat exchanger It is effective to raise the temperature of the cooling water using the heat recovered by the heating means.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
(Embodiment 1)
FIG. 1 is a block configuration diagram of a fuel cell cogeneration system according to Embodiment 1 of the present invention. 1, those having the same functions as those of the conventional fuel cell cogeneration system shown in FIG. 7 are given the same reference numerals, and the details of those functions are described as being equivalent to those of FIG. Omitted.
[0016]
In FIG. 1, an additional heating means 6 is arranged on the upper part of the fuel cell 1, and a raw material gas supply is connected to the fuel cell 1 and the additional heating means 6 by a branch pipe from a raw material gas supply valve 2. Water supply to the hot water storage tank 4 is connected to the lower part of the hot water storage tank 4 from the water supply valve 12. The exhaust heat recovery accompanying the power generation reaction of the fuel cell 1 is performed by taking the water in the lower layer of the hot water storage tank 4 into the fuel cell 1 from the lower part of the hot water storage tank 4 through the exhaust heat recovery pipe 3 and storing the hot water after the exhaust heat recovery from the fuel cell 1. It is connected so as to return to the upper part of the tank 4. Hot water from the hot water storage tank 4 is connected so as to be supplied to the reheating heating means 6 via the hot water supply pipe 5, and is connected to the water supply port 13 of the reheating heating means 6 adjacent to the upper part of the hot water storage tank 4 by a short circuit pipe. It is connected. The hot water chased from the chasing heating means 6 is connected so as to be supplied from the hot water tap 7 via the hot water supply pipe 8. These fuel cell 1, hot water storage tank 4, reheating heating means 6, exhaust heat recovery pipe 3, hot water discharge pipe 5, etc. are provided in the exterior 14, and each pipe is shortest and a heat insulating material (not shown) is provided. Shared, integrated and connected.
[0017]
In the above-described configuration, the exhaust heat recovery of the fuel cell was performed by collecting the water in the hot water storage tank into the fuel cell, and the exhaust heat recovery was performed. It is also possible to use a configuration in which exhaust heat is recovered through the system.
[0018]
Next, the operation and action will be described.
[0019]
First, since the temperature is raised to a temperature suitable for the operation of the fuel cell 1 (70 to 80 ° C.) at the time of fuel cell start-up and power generation, the fuel cell portion is connected to the memory heating means 6 sharing the heat insulating material with the fuel cell 1. Residual heat rises, and the hot and cold hot water supply pipes and hot water supply pipes, which are the inlet and outlet pipes of the remedy heating means, are kept warm, making it difficult to cool, and reducing the temperature drop of hot water in the pipes.
[0020]
In addition, the fuel cell, hot water storage tank, and remedy heating means are connected in a single exterior, and the hot water storage tank is a stacked hot water storage system in which warm hot water is stored from the top. Hot water is supplied from the top of the hot water storage tank. The hot water supply piping between the fuel cell and hot water storage tank and between the hot water storage tank and additional heating means is connected with the shortest circuit to reduce the size, and the fuel cell, hot water storage tank and additional heating means are insulated. Since heat is shared, waste heat loss can be reduced.
[0021]
Further, in the fuel cell 1, a reformer (not shown) as fuel gas supply means, a blower fan (not shown) as oxidant gas supply means, a humidifier, and fuel gas and oxidant gas are provided. A heavy component such as a fuel cell main body (not shown) that generates electric power by reacting is mounted, and a memorial heating means 6 having a relatively light component such as a heat exchanger and a burner mounted on the lower part of the fuel cell. Is placed on the upper part of the fuel cell 1, so that the installation stability of the entire device in the exterior 14 is good. Further, when the replacement of the heavy parts of the fuel cell 1 occurs, it is not necessary to pull down the heavy parts from a high position, and the service and maintainability are excellent.
[0022]
(Embodiment 2)
FIG. 2 is a block diagram of a fuel cell cogeneration system according to Embodiment 2 of the present invention.
[0023]
2, those having the same functions as those of the fuel cell cogeneration system of Embodiment 1 shown in FIG. 1 are given the same reference numerals, and the details of those functions are similar to those of FIG. The description will be omitted.
[0024]
In FIG. 2, reference numeral 20 denotes a fuel cell main body, a fuel gas supply means 21 supplies a raw material gas such as natural gas, one to a reformer burner heating unit 23 via a combustion gas supply valve 22, and the other a raw material gas. The fuel gas is supplied to the reformer 25 through the supply valve 24, is heated and steam reformed, and is connected so as to generate a fuel gas mainly containing hydrogen and supply it to the fuel cell body 20.
[0025]
The fuel gas supply means 21 is provided with a first exhaust gas heat exchanger 27 between the reformer burner heating section 23 and the first exhaust gas path 26.
[0026]
Reference numeral 28 denotes a blower fan as an air supply device, which supplies oxidant air to the fuel cell body 20. At this time, the supply air is humidified by the oxidation side humidifier 29. The fuel cell main body 20 includes a cooling water pipe 30 that sends and cools cooling water, and a cooling water pump 31 that circulates water in the cooling water pipe.
[0027]
Further, at the time of power generation, exhaust heat generated by the power generation of the fuel cell main body 20 by the cooling water heat exchanger 32 and the circulation pump 33 is discharged from the exhaust heat recovery pipe 34 in the fuel cell to the hot water storage tank 4 via the exhaust heat recovery pipe 3. Connected to collect. A dotted line 1 including the fuel cell body 20 is a so-called fuel cell.
[0028]
The hot water storage tank 4 is supplied with water from a water supply port 35 at the lower part of the hot water storage tank 4, a part is branched into a water supply pipe 36, hot water is supplied from a hot water supply port 37 at the lower part of the hot water storage tank 4 through the hot water supply pipe 5, and supplied to the mixing valve 38. So connected.
[0029]
The control means 39 controls the mixing ratio of the mixing valve 38 so that the hot water and water from the hot water storage tank 4 become the hot water supply demand set temperature by the mixing temperature detection means 40 such as a thermistor, and the hot water storage temperature detection means (thermistor etc.) 41. Thus, the hot water storage tank 4 is connected to control the circulation flow rate of the circulation pump 33 so that the hot water storage temperature becomes constant at a high temperature (70 to 80 ° C.). Further, the supply gas to the fuel gas supply means 21 is controlled by the combustion gas supply valve 22 and the raw material gas supply valve 24, the amount of air supplied from the air supply device 28 is controlled, and the cooling water flow rate of the fuel cell body 20 is cooled. It connects so that it may control via the water pump 31. FIG.
[0030]
On the downstream side of the mixing valve 38, the hot water heated by the reheating heater 42 is piped so as to be discharged from the hot water tap 43 via the hot water supply pipe 8. An additional raw material gas supply valve 45 for supplying raw gas to the additional heating burner 44 is connected to the additional heating unit 42 and extends from the additional heating heat exchanger 46 to the second exhaust gas path 47 on the downstream side. A second exhaust gas heat exchanger 48 is installed. Further, when the hot water storage temperature in the hot water storage tank 4 is equal to or lower than the hot water supply demand set temperature by the additional heating temperature detection means (thermistor or the like) 49, the control means 39 combusts the additional heating burner 44 so that the hot water supply demand set temperature is reached. The amount is connected so as to adjust the gas amount of the memorizing raw material gas supply valve 45. A dotted line 6 including the memorial heating unit 42 is memorial heating means. These fuel cell 1, hot water storage tank 4, reheating heating means 6, exhaust heat recovery pipe 3, hot water discharge pipe 5, etc. are provided in the exterior 14, and each pipe is shortest and a heat insulating material (not shown) is provided. Shared, integrated and connected.
[0031]
Next, the operation and action will be described.
[0032]
First, when the fuel cell is started, the control means 39 controls the combustion amount of the reformer burner heating section 23 of the fuel gas supply means 21 to heat the reformer 25 and to heat mainly the reformer 25. When the fuel gas as a component falls below a predetermined carbon monoxide concentration (about 10 to 20 ppm), the fuel gas is supplied to the fuel cell body 20.
[0033]
Next, at the time of fuel cell power generation, the control means 39 first takes out the exhaust gas from the combustion of the reformer burner heating unit 23 of the fuel gas supply means 21 from the lower part of the hot water storage tank 4 via the first exhaust gas heat exchanger 27. Heat is recovered to the exhaust heat recovery pipe 34 in the fuel cell through which the heat transport medium such as water flows. Next, the exhaust gas accompanying the power generation reaction of the fuel cell main body 20 by the fuel gas mainly composed of hydrogen supplied from the reformer 25 of the fuel gas supply means 21 and the air (oxygen) supplied from the air supply device 28. The cooling water pump 31 is operated to recover heat to the exhaust heat recovery piping 34 side in the fuel cell via the cooling water heat exchanger 32. The control means 39 recovers exhaust heat in the order of the first exhaust gas heat exchanger 27 and the cooling water heat exchanger 32, and the hot water storage temperature detection means 41 makes the hot water storage temperature of the hot water storage tank 4 constant at a high temperature (70 to 80 ° C.). Thus, the circulation flow rate of the circulation pump 33 is controlled.
[0034]
When the hot water storage tank 4 is full of hot water, the circulation pump is stopped and the exhaust heat recovery via the exhaust heat recovery pipe 34 in the fuel cell and the exhaust heat recovery pipe 3 is completed.
[0035]
Next, when the amount of hot water stored in the hot water storage tank 4 is sufficient, the mixed temperature detection value in the mixed temperature detecting means 40 is higher than the hot water supply demand setting temperature when hot water is used by the hot water tap 43, so No operation is required, and the hot water is supplied directly to the hot water tap 43 side.
[0036]
Next, when the amount of hot water stored in the hot water storage tank 4 is small and insufficient, if the mixed temperature detection value in the mixed temperature detecting means 40 becomes lower than the hot water supply demand set temperature when hot water is used by the hot water tap 43, the memorial heating unit The reheating operation at 42 is required, and the control means 39 uses the reheating heating temperature detection means 49 to change the combustion amount of the reheating heating burner 44 so that the hot water supply demand setting temperature is reached, and the gas in the reheating raw material gas supply valve 45. Adjust by adjusting the amount.
[0037]
At this time, when the fuel cell main body 20 is generating electric power, the control means 39 first causes the first exhaust gas heat exchanger 27 to be discharged from the exhaust gas generated by the combustion of the reformer burner heating unit 23 of the fuel gas supply means 21. Then, heat is recovered from the hot water storage tank 4 toward the exhaust heat recovery pipe 34 in the fuel cell, and from the exhaust gas generated by the combustion of the additional heating burner heating unit 44 of the additional heating unit 42 via the second exhaust gas heat exchanger 48. Then, heat recovery of the exhaust gas is performed to the fuel cell exhaust heat recovery pipe 34 side of the hot water storage tank 4. Next, the cooling water pump 31 is operated for the exhaust heat accompanying the power generation reaction of the fuel cell main body 20 by the fuel gas mainly containing hydrogen and air (oxygen), and the inside of the fuel cell is passed through the cooling water heat exchanger 32. Heat is recovered to the exhaust heat recovery pipe 34 side. The control means 39 recovers exhaust heat in the order of the first exhaust gas heat exchanger 27, the second exhaust gas heat exchanger 48, and the cooling water heat exchanger 32, and the hot water storage temperature detection means 41 causes the hot water storage temperature of the hot water storage tank 4 to be high. (70 to 80 ° C.) The circulation flow rate of the circulation pump 33 is controlled to be constant.
[0038]
Therefore, during the power generation of the fuel cell body 20 and during the additional heating of the additional heating unit 42, the amount of exhaust heat recovered to the hot water storage tank 4 becomes the amount of exhaust heat recovered by the cooling water heat exchanger 32, and the first exhaust gas in the exhaust gas path. Heat recovery efficiency is improved because the exhaust heat recovery metering by the heat exchanger 27 and / or the second exhaust gas heat exchanger 48 is added.
[0039]
(Embodiment 3)
FIG. 3 is a block diagram of a fuel cell cogeneration system according to Embodiment 3 of the present invention.
[0040]
The difference from the second embodiment is that an integrated exhaust gas path 50 in which the exhaust gas path of the reformer burner heating unit 23 of the fuel gas supply means 21 and the exhaust gas path of the additional heating unit 42 are combined, and the integrated exhaust gas path 50 An integrated exhaust gas heat exchanger 51 that performs heat recovery of the exhaust gas is provided.
[0041]
In addition, the thing of the same code | symbol as Embodiment 1, 2 has the same structure, and abbreviate | omits description.
[0042]
Next, the operation and action will be described.
[0043]
First, when the fuel cell is started, the control means 39 controls the combustion amount of the reformer burner heating section 23 of the fuel gas supply means 21 to heat the reformer 25 and to heat mainly the reformer 25. When the fuel gas as a component falls below a predetermined carbon monoxide concentration (about 10 to 20 ppm), the fuel gas is supplied to the fuel cell body 20.
[0044]
Next, at the time of fuel cell power generation, the control means 39 first causes the exhaust heat recovery pipe 34 in the fuel cell to pass through the integrated exhaust gas heat exchanger 51 from the exhaust gas generated by combustion in the reformer burner heating unit 23 of the fuel gas supply means 21. Heat recovery to the side. Next, the exhaust gas accompanying the power generation reaction of the fuel cell main body 20 by the fuel gas mainly composed of hydrogen supplied from the reformer 25 of the fuel gas supply means 21 and the air (oxygen) supplied from the air supply device 28. The cooling water pump 31 is operated to recover heat to the exhaust heat recovery piping 34 side in the fuel cell via the cooling water heat exchanger 32. The control means 39 recovers the exhaust heat in the order of the integrated exhaust gas heat exchanger 51 and the cooling water heat exchanger 32 so that the hot water storage temperature of the hot water storage tank 4 is kept constant at a high temperature (70 to 80 ° C.) by the hot water storage temperature detection means 41. The circulation flow rate of the circulation pump 33 is controlled.
[0045]
When the hot water storage tank 4 is full of hot water, the circulation pump is stopped and the exhaust heat recovery via the exhaust heat recovery pipe 34 in the fuel cell and the exhaust heat recovery pipe 3 is completed.
[0046]
When the amount of hot water stored in the hot water storage tank 4 is small and insufficient, the regenerative heating burner is set to the hot water supply demand set temperature by the reheating heating temperature detecting means 49 via the reheating heating unit 42 as in the first embodiment. 44 is adjusted.
[0047]
Therefore, when the fuel cell main body 20 generates power and when the remedy heating unit 42 performs remedy heating, the exhaust heat recovery to the hot water storage tank 4 is performed by the integrated exhaust gas heat exchanger 51 in the integrated exhaust gas path 50 and the cooling water heat exchanger. Since the exhaust heat recovery of the power generation reaction by 32 is added, the heat recovery efficiency is improved. Further, the exhaust gas path of the reformer burner heating unit 23 of the fuel cell main body 20 and the exhaust gas path of the additional heating unit 42 are combined so that the exhaust gas heat recovery is performed by one exhaust gas heat exchanger, whereby the fuel cell. Cost reduction, size reduction, and high efficiency can be achieved as a cogeneration system.
[0048]
(Embodiment 4)
FIG. 4 is a block diagram of a fuel cell cogeneration system according to Embodiment 4 of the present invention.
[0049]
The difference from the second embodiment is that the bypass circuit 52 for bypassing the second exhaust gas heat exchanger 48 in the exhaust gas path 47 of the additional heating unit 42, the bypass circuit 52, and the bypass valve for switching the second exhaust gas heat exchanger 48. 53 is provided.
[0050]
In addition, the thing of the same code | symbol as Embodiment 1 has the same structure, and abbreviate | omits description.
[0051]
Next, the operation and action will be described.
[0052]
At the time of fuel cell power generation, the control means 39 first causes the exhaust gas from combustion from the reformer burner heating section 23 of the fuel gas supply means 21 to the exhaust heat recovery pipe 34 side in the fuel cell via the first exhaust gas heat exchanger 27. Heat recovery. At this time, if the remedy heating unit 42 is not operating, the second exhaust gas heat exchanger 48 is connected via the bypass valve 53 via the bypass circuit 52 and if the remedy heating unit 42 is operating. Heat recovery via. Next, the exhaust gas accompanying the power generation reaction of the fuel cell main body 20 by the fuel gas mainly composed of hydrogen supplied from the reformer 25 of the fuel gas supply means 21 and the air (oxygen) supplied from the air supply device 28. The cooling water pump 31 is operated to recover heat to the exhaust heat recovery piping 34 side in the fuel cell via the cooling water heat exchanger 32. The control means 39 recovers exhaust heat in the order of the first exhaust gas heat exchanger 27 and / or the second exhaust gas heat exchanger 48 and the cooling water heat exchanger 32, and the hot water storage temperature detection means 41 causes the hot water storage temperature of the hot water storage tank 4 to be recovered. The circulation flow rate of the circulation pump 33 is controlled so that the temperature becomes constant at a high temperature (70 to 80 ° C.).
[0053]
When the hot water storage tank 4 is full of hot water, the circulation pump is stopped and the exhaust heat recovery via the exhaust heat recovery pipe 34 in the fuel cell and the exhaust heat recovery pipe 3 is completed.
[0054]
When the amount of hot water stored in the hot water storage tank 4 is small and insufficient, the regenerative heating burner is set to the hot water supply demand set temperature by the additional heating temperature detecting means 49 via the additional heating unit 42 as in the second embodiment. 44 is adjusted.
[0055]
Therefore, when the fuel cell main body 20 generates power and when the reheating heater 42 is not operating, the exhaust heat recovery to the hot water storage tank 4 is performed by the exhaust heat recovery by the first exhaust gas heat exchanger 27 in the first exhaust gas path 27 and the cooling water. It is performed by the exhaust heat recovery of the power generation reaction by the heat exchanger 32, and is performed without going through the second exhaust gas heat exchanger 48 of the second exhaust gas path 47 of the additional heating unit 42. It is possible to eliminate heat loss and further increase efficiency.
[0056]
(Embodiment 5)
FIG. 5 is a block diagram of a fuel cell cogeneration system according to Embodiment 5 of the present invention.
[0057]
The difference from the second embodiment is that a fuel exhaust gas heat exchanger 54 that recovers heat in the fuel exhaust gas after chemically reacting with the fuel cell main body 20 is replaced with a second exhaust gas heat exchanger 48 and a cooling water heat exchanger 32. It is the point arranged between.
[0058]
In addition, the thing of the same code | symbol as Embodiment 1 has the same structure, and abbreviate | omits description.
[0059]
Next, the operation and action will be described.
[0060]
At the time of fuel cell power generation, the control means 39 first causes the exhaust gas from combustion from the reformer burner heating section 23 of the fuel gas supply means 21 to the exhaust heat recovery pipe 34 side in the fuel cell via the first exhaust gas heat exchanger 27. Heat recovery. At this time, if the reheating heater 42 is operating, the second exhaust gas heat exchanger 48 further performs heat recovery of the exhaust gas of the reheating heater. Next, heat in the fuel exhaust gas after chemically reacting with the fuel cell main body 20 is recovered through the fuel exhaust gas heat exchanger 54. Further, the exhaust heat accompanying the power generation reaction of the fuel cell main body 20 is operated by the cooling water pump 31 to recover heat to the in-fuel cell exhaust heat recovery pipe 34 side via the cooling water heat exchanger 32. The control means 39 recovers exhaust heat in the order of the first exhaust gas heat exchanger 27, the second exhaust gas heat exchanger 48, the fuel exhaust gas heat exchanger 54, and the cooling water heat exchanger 32, and stores hot water storage temperature detection means (thermistor). 41 is used to control the circulation flow rate of the circulation pump 33 so that the hot water storage temperature of the hot water storage tank 4 is constant at a high temperature (70 to 80 ° C.).
[0061]
When the hot water storage tank 4 is full of hot water, the circulation pump is stopped and the exhaust heat recovery via the exhaust heat recovery pipe 34 in the fuel cell and the exhaust heat recovery pipe 3 is completed.
[0062]
When the amount of hot water stored in the hot water storage tank 4 is small and insufficient, the regenerative heating burner is set to the hot water supply demand set temperature by the additional heating temperature detecting means 49 via the additional heating unit 42 as in the second embodiment. 44 is adjusted.
[0063]
Therefore, the heat recovery to the hot water storage tank is performed after the heat recovery by the exhaust gas heat exchanger of the reformer burner heating section of the fuel cell and / or the exhaust gas heat exchanger of the additional heating means, and then after the chemical reaction with the fuel cell. Low-temperature heat exchange of exhaust gas and hot water by performing heat recovery through a fuel exhaust gas heat exchanger that recovers heat from the fuel exhaust gas, and then through a cooling water heat exchanger by cooling water circulation during power generation of the fuel cell ( By sequentially performing high-temperature heat exchange (water-water heat exchange) of cooling water and hot water of the fuel cell from gas-water heat exchange), the exhaust heat recovery efficiency of the fuel cell and the additional heating means is further improved.
[0064]
In this embodiment, the fuel exhaust gas heat exchanger that recovers heat in the fuel exhaust gas after the chemical reaction with the fuel cell is provided between the exhaust gas heat exchanger and the cooling water heat exchanger. Needless to say, a configuration provided with an oxidant exhaust gas heat exchanger that recovers heat in the oxidant exhaust gas after chemically reacting with the battery has the same effect.
[0065]
Further, even if the configuration of the heat exchanger embodiment 2, 3 or 4 is adopted for the exhaust gas heat exchanger of the reformer burner heating section and / or the exhaust gas of the additional heating means, the same effect can be obtained. Needless to say.
[0066]
(Embodiment 6)
FIG. 6 is a block diagram of a fuel cell cogeneration system according to Embodiment 6 of the present invention.
[0067]
The difference from the second embodiment is that
A cooling water bypass valve 55 for bypassing the cooling water heat exchanger 32 in the circulation path of the cooling water pipe 30 and a heating means 56 such as a heater for heating the cooling water when the fuel cell body 20 is activated are provided in the bypass circuit. point. Further, a hot water storage tank bypass valve 58, 59 for switching to a hot water storage tank bypass circuit 57 for bypassing the recovered heat to the hot water storage tank is provided.
[0068]
In addition, the thing of the same code | symbol as Embodiment 2 has the same structure, and abbreviate | omits description.
[0069]
Next, the operation and action will be described.
[0070]
First, when the fuel cell is started, the control means 39 controls the combustion amount of the reformer burner heating section 23 of the fuel gas supply means 21 to heat the reformer 25 and to heat mainly the reformer 25. When the fuel gas as a component falls below a predetermined carbon monoxide concentration (about 10 to 20 ppm), the fuel gas is supplied to the fuel cell body 20.
[0071]
At this time, the cooling water bypass valve 55 is bypassed to the heating means 56 side, and the cooling water of the fuel cell body 20 is heated by the heating means (heater) 56 to a temperature suitable for power generation.
[0072]
Further, the hot water storage tank bypass valves 58 and 59 are switched to the hot water storage tank bypass circuit 57 side, and the exhaust gas heat from the combustion of the reformer burner heating unit 23 is exhausted through the first exhaust gas heat exchanger 27 to the exhaust heat recovery pipe 34 in the fuel cell. Heat recovery to the side. Then, the circulating pump 33 exhausts and circulates the closed circuit of the exhaust heat recovery pipe 34 in the fuel cell and the hot water tank bypass circuit 57. The recovered heat from the exhaust gas heat exchanger 27 is recovered through the cooling water heat exchanger 32 to the cooling water pipe 30 side, and the valve opening degree of the cooling water bypass valve 55 is adjusted. The fuel cell body 20 is heated by the recovered heat and the heating means (heater) 56 and the recovered heat.
[0073]
Next, at the time of fuel cell power generation, the control means 39 firstly exhausts the exhaust heat recovery pipe in the fuel cell from the exhaust gas generated by the combustion of the reformer burner heating unit 23 of the fuel gas supply means 21 via the first exhaust gas heat exchanger. Heat is recovered to the 34th side. Next, the cooling water bypass valve is passed to the cooling water heat exchanger side, the exhaust heat accompanying the power generation reaction of the fuel cell main body 20 is operated, the cooling water pump 31 is operated, and the exhaust water in the fuel cell is discharged via the cooling water heat exchanger 32. Heat is recovered to the heat recovery pipe 34 side. The hot water tank bypass valves 58 and 59 are switched from the hot water tank bypass circuit 57 side to the exhaust heat recovery side to the hot water tank 4. The control means 39 recovers exhaust heat in the order of the first exhaust gas heat exchanger 27 and the cooling water heat exchanger 32, and the hot water storage temperature of the hot water storage tank 4 is high (70 to 80 ° C.) by the hot water storage temperature detection means (thermistor) 41. The circulation flow rate of the circulation pump 33 is controlled so as to be constant.
[0074]
Therefore, when the fuel cell is started, the bypass ratio of the cooling water heat exchanger 32 in the cooling water circulation path is adjusted, and the cooling water is recovered by recovering the heat from the exhaust gas heat exchanger 27 and the heating means (heater) 56 and the both. By raising the temperature and heating the fuel cell, when the fuel cell is started, the temperature of the cooling water for starting the fuel cell can be increased quickly, enabling a short-time start, and further improving usability.
[0075]
It should be noted that the same effect can be obtained even if the configuration of the heat exchanger of Embodiment 2, 3, 4 or 5 is adopted for the exhaust gas heat exchanger of the reformer burner heating section and / or the exhaust gas of the additional heating means. Needless to say.
[0076]
【The invention's effect】
As is apparent from the above description, according to the fuel cell cogeneration system of the present invention, the following effects can be obtained.
[0077]
1) A fuel cell and additional heating means are placed close to the side of the hot water storage tank to react a reformer as a fuel gas supply means, a blower fan as a oxidant gas supply means, a humidifier, and a fuel gas and an oxidant gas. By placing a fuel cell with heavy components such as a fuel cell body that generates electricity and having a heating unit with relatively lightweight components such as a heat exchanger and a burner at the top of the fuel cell, It is excellent in installation stability of the entire device, and can improve service and maintenance such as replacement of heavy parts such as a fuel cell body.
[0078]
2) Since the fuel cell is provided in the lower part of the memory heating means and the operating temperature of the fuel cell is as high as 70 to 80 ° C., the residual heat rises from the fuel cell part during the fuel cell operation, and the memory heating means is turned on. The outlet piping and hot water supply piping, which are outlet piping, are kept warm, making it difficult to cool, and the phenomenon that the hot water in the piping before and after the hot water is cooled (so-called pre-cooling, cold water sandwich phenomenon), which is a problem unique to hot water heaters, is alleviated. .
[0079]
3) By connecting the fuel cell, the hot water storage tank, and the additional heating means within one exterior, the hot water supply piping between the fuel cell and the hot water storage tank, and between the hot water storage tank and the additional heating means can be simplified and minimized. In addition, since the fuel cell, the hot water storage tank, and the additional heating means can be shared, such as a heat insulating material, further miniaturization and high efficiency can be achieved by reducing waste heat loss.
[0080]
4) The heat recovery efficiency of the exhaust gas from the reformer burner heating section of the fuel cell and the exhaust gas from the additional heating means can be improved, and the heat recovery by the exhaust gas heat exchanger can be improved. By performing the heat recovery through the cooling water heat exchanger by circulating the cooling water of the exhaust heat generated during power generation, efficient exhaust heat recovery can be realized by the heat exchange of the cooling water of the fuel cell after the latent heat recovery of the exhaust gas. High-efficiency cogeneration equipment can be provided.
[0081]
5) Combining the exhaust gas path of the reformer burner heating part of the fuel cell and the exhaust gas path of the additional heating means, and recovering the exhaust gas heat with one exhaust gas heat exchanger, cost reduction and miniaturization High efficiency can be achieved.
[0082]
6) When the remedy heating means is not in operation, the exhaust gas heat exchanger in the exhaust gas path of the remedy heating means is bypassed, thereby reducing the heat loss due to passing through the exhaust gas heat exchanger in the exhaust gas path of the remedy heating means. It is possible to achieve higher efficiency.
[0083]
7) After recovering heat to the hot water storage tank, heat recovery by the exhaust gas heat exchanger of the reformer burner heating part of the fuel cell and / or exhaust gas heat exchanger of the additional heating means, and then chemical reaction with the fuel cell A fuel exhaust gas heat exchanger that recovers heat in the fuel exhaust gas and / or an oxidant exhaust gas heat exchanger that recovers heat in the oxidant exhaust gas after chemical reaction with the fuel cell, and further cooling the fuel cell during power generation By performing heat recovery through the cooling water heat exchanger by water circulation in order, low-temperature heat exchange (gas-water heat exchange) of exhaust gas and hot water for hot water (water-water) By sequentially performing (heat exchange), the exhaust heat recovery efficiency of the fuel cell and the additional heating means is further improved.
[0084]
8) When the fuel cell is started, the bypass ratio of the cooling water heat exchanger 32 in the cooling water circulation path is adjusted, and the cooling water is recovered by recovering heat from the exhaust gas heat exchanger 27 and the heating means (heater) 57 and both. By raising the temperature and heating the fuel cell, when the fuel cell is started, the temperature of the cooling water for starting the fuel cell is increased quickly, enabling a short-time start, and improving the usability.
[Brief description of the drawings]
FIG. 1 is a block configuration diagram of a fuel cell cogeneration system according to a first embodiment of the present invention.
FIG. 2 is a block configuration diagram of a fuel cell cogeneration system according to a second embodiment of the present invention.
FIG. 3 is a block diagram of a fuel cell cogeneration system according to Embodiment 3 of the present invention.
FIG. 4 is a block configuration diagram of a fuel cell cogeneration system according to a fourth embodiment of the present invention.
FIG. 5 is a block configuration diagram of a fuel cell cogeneration system according to a fifth embodiment of the present invention.
FIG. 6 is a block diagram of a fuel cell cogeneration system according to a sixth embodiment of the present invention.
FIG. 7 is a block diagram of a conventional exhaust heat recovery device.
[Explanation of symbols]
1 Fuel cell
3 Waste heat recovery piping
4 Hot water storage tank
5 Hot water piping
6 memorial heating means
14 Exterior
23 Reformer burner heating section
27 First exhaust gas heat exchanger
32 Cooling water heat exchanger
48 Second exhaust gas heat exchanger
51 Integrated exhaust gas heat exchanger
52,57 Bypass circuit
54 Combustion exhaust gas heat exchanger

Claims

A fuel cell that generates electric power by reacting a fuel gas and an oxidant gas; a hot water storage tank that recovers exhaust heat during power generation of the fuel cell; and a reheating heater that heats the hot water in the hot water storage tank And a fuel cell cogeneration system in which the reheating heating means and the fuel cell are disposed on a side of the hot water storage tank, and the reheating heating means is disposed on an upper portion of the fuel cell.

2. The fuel cell cogeneration system according to claim 1, wherein at least the hot water storage tank and the reheating heater are housed in one exterior having a heat insulating material.

3. The fuel cell cogeneration system according to claim 2, wherein the hot water storage tank is a stacked type in which hot water is stored from above the hot water storage tank.

An exhaust gas heat exchanger that recovers heat of at least one of a burner heating section that heats the reformer that generates the fuel gas and the additional heating means, and heat in cooling water that cools the fuel cell. A cooling water heat exchanger to be recovered, and heat recovery to the hot water storage tank is performed in the order of (1) heat recovery by the exhaust gas heat exchanger and (2) heat recovery by the cooling water heat exchanger. The fuel cell cogeneration system according to claim 1.

5. The fuel cell cogeneration system according to claim 4, wherein the exhaust gas path of the reformer burner heating part and the exhaust gas path of the additional heating means are coupled to perform exhaust gas heat recovery with a single exhaust gas heat exchanger. system.

5. The fuel cell cogeneration system according to claim 4, further comprising a bypass circuit that bypasses the exhaust gas heat exchanger in the exhaust gas path of the additional heating means when the additional heating means is not in operation.

The exhaust gas heat exchanger that recovers the heat in the fuel exhaust gas from the fuel cell and the heat in the oxidant exhaust gas from the fuel cell downstream of the exhaust gas heat exchanger and upstream of the cooling water heat exchanger. 7. The fuel cell cogeneration system according to claim 4, further comprising at least one of an oxidant exhaust gas heat exchanger for heat recovery.

A hot water tank bypass circuit that bypasses an exhaust heat recovery path from the hot water storage tank to the cooling water heat exchanger and an exhaust heat recovery path from the hot water storage tank to the exhaust gas heat exchanger; and the cooling water on the cooling water circulation path A bypass circuit for bypassing the heat exchanger; and heating means on the bypass circuit, and switching to the hot water tank bypass circuit when the fuel cell is started, and the heat recovered by the heating means via the cooling water heat exchanger The fuel cell cogeneration system according to any one of claims 4 to 7, wherein the temperature of the cooling water is raised using