JP3904402B2

JP3904402B2 - Home fuel cell system

Info

Publication number: JP3904402B2
Application number: JP2001092924A
Authority: JP
Inventors: 雄治澤田; 一裕平井
Original assignee: Osaka Gas Co Ltd
Current assignee: Osaka Gas Co Ltd
Priority date: 2001-03-28
Filing date: 2001-03-28
Publication date: 2007-04-11
Anticipated expiration: 2021-03-28
Also published as: JP2002289239A

Description

【０００１】
【発明の属する技術分野】
本発明は、電気と熱とを発生させる燃料電池からの排熱により加熱された湯を貯湯槽に蓄えるとともに、燃料電池の発電電力量を制御する制御手段とを備えて構成した家庭用燃料電池システムに関する。
【０００２】
【従来の技術】
この種の家庭用燃料電池システムでは、燃料電池の発電電力に応じて発生する熱を貯湯槽に一旦蓄え、給湯需要に応じて供給するようにしている。給湯需要が多くて、貯湯槽内の蓄熱量が不足した場合、別途設置したボイラーなどの補助加熱装置によって温水を補充している。
【０００３】
【発明が解決しようとする課題】
しかしながら、従来一般に、使用電力に応じて発電電力量を制御する、いわゆる電主熱従運転が主体であり、給湯需要が少なくて、貯湯槽内に上限温度の湯が満杯に蓄えられた場合、燃料電池からの排熱を放熱しながら発電を継続しており、排熱の回収効率が低下して省エネルギー性が低下する欠点があった。
【０００４】
また、放熱を回避するために、大型の貯湯槽を設けることも考えられたが、イニシャルコストが増大するとともに、貯湯槽およびそれに付帯する設備自体からの放熱量も多くなってエネルギーロスを生じやすく、省エネルギー性が低下する欠点があった。
【０００５】
本発明は、このような事情に鑑みてなされたものであって、請求項１に係る発明は、燃料電池を継続して運転できながら、燃料電池からの排熱の放熱を極力減少させて省エネルギー性を向上できるようにすることを目的とし、また、請求項２に係る発明は、燃料電池を継続して運転できながら、燃料電池からの排熱の放熱を極力減少させて省エネルギー性を向上できるとともに給湯需要のピークに対して良好に対応できるようにすることを目的とする。
【０００６】
【課題を解決するための手段】
請求項１に係る発明は、上述のような目的を達成するために、
電気と熱とを発生させる燃料電池と、
前記燃料電池からの排熱により加熱された湯を蓄える貯湯槽と、
前記燃料電池の発電電力量を制御する制御手段とを備えた家庭用燃料電池システムにおいて、
前記貯湯槽内に蓄えられた熱量を測定する蓄熱量センサと、
前記貯湯槽内の最大蓄熱量よりも低い蓄熱量を設定する蓄熱量設定手段と、
前記蓄熱量センサで測定される蓄熱量と前記蓄熱量設定手段で設定された蓄熱量とを比較し、測定蓄熱量が設定蓄熱量まで上昇したときに指令信号を出力する蓄熱量比較手段と、
前記指令信号に応答して前記制御手段による制御発電電力量が最大発電電力量よりも小さい設定電力量になるように調整する発電電力量調整手段とを備えて構成する。
【０００７】
また、請求項２に係る発明は、前述のような目的を達成するために、
電気と熱とを発生させる燃料電池と、
前記燃料電池からの排熱により加熱された湯を蓄える貯湯槽と、
前記燃料電池の発電電力量を制御する制御手段とを備えた家庭用燃料電池システムにおいて、
前記貯湯槽内に蓄えられた熱量を測定する蓄熱量センサと、
前記貯湯槽内の最大蓄熱量よりも少ない二段階の高蓄熱量と低蓄熱量とを設定する蓄熱量設定手段と、
前記蓄熱量センサで測定される蓄熱量と前記蓄熱量設定手段で設定された低蓄熱量と高蓄熱量とを比較し、測定蓄熱量が設定低蓄熱量まで上昇したときに低蓄熱指令信号を、測定蓄熱量が設定高蓄熱量まで上昇したときに高蓄熱量指令信号をそれぞれ出力する蓄熱量比較手段と、
給湯需要の経時的変化から給湯需要のピークとなる時間帯を特定するピーク需要特定手段と、
前記低蓄熱指令信号に応答して、その信号出力時刻が前記ピーク需要特定手段で特定されているピークとなる時間帯の直前かどうかを判別し、直前のときに直前信号を出力する直前判別手段と、
前記低蓄熱指令信号に応答して、前記直前判別手段からの直前信号の有無を判別し、前記直前信号が無いときには、前記制御手段による制御発電電力量が最大発電電力量よりも小さい設定電力量になるように調整し、前記直前信号が有るときには、前記制御手段を作動させず、かつ、前記高蓄熱指令信号に応答して、前記制御手段による制御発電電力量が最大発電電力量よりも小さい設定電力量になるように調整する発電電力量調整手段とを備えて構成する。
【０００８】
【作用】
請求項１に係る発明の家庭用燃料電池システムの構成によれば、貯湯槽内に蓄えられた熱量が増加していくときに、最大蓄熱量よりも低い設定蓄熱量になった時点で、燃料電池の発電電力量を最大発電電力量よりも小さい設定電力量になるように調整し、排熱量の発生量を抑えて貯湯槽内の蓄熱量が満杯になるまでの時間を延ばすことができる。
【０００９】
また、請求項２に係る発明の家庭用燃料電池システムの構成によれば、給湯需要の経時的変化を考慮し、給湯需要のピークとなる時間帯に近くないときには、貯湯槽内に蓄えられた熱量が増加していくときに、最大蓄熱量よりも低い値に設定した高設定蓄熱量よりも更に低い低設定蓄熱量になった時点で、燃料電池の発電電力量を最大発電電力量よりも小さい設定電力量になるように調整し、排熱量の発生量を抑えて貯湯槽内の蓄熱量が満杯になるまでの時間を延ばすことができる。
一方、給湯需要のピークとなる時間帯に近いときには、貯湯槽内に蓄えられた熱量が増加していくときに、最大蓄熱量よりも低いが低設定蓄熱量よりも高い値に設定した高設定蓄熱量になった時点で、燃料電池の発電電力量を最大発電電力量よりも小さい設定電力量になるように調整し、排熱量の発生量を抑えて貯湯槽内の蓄熱量が満杯になるまでの時間を延ばすとともに、ピークとなる時間帯になったときに、極力多量の蓄熱量を確保しておくようにできる。
【００１０】
【発明の実施の形態】
次に、本発明の実施例を図面に基づいて詳細に説明する。
図１は、本発明に係る家庭用燃料電池システムの第１実施例のシステム構成図であり、電気と熱とを発生させる燃料電池１と貯湯槽２とが、循環ポンプ３を介装した循環配管４を介して接続され、燃料電池１で発生する排熱により水を加熱して湯を得、その湯を貯湯槽２に蓄えるように構成されている。
【００１１】
燃料電池１からの電力出力線５に負荷としての家電機器６が接続されるとともに、電力出力線５に商用電源７が系統連係され、燃料電池１からの発電電力を家電機器６に供給するとともに不足分の電力を商用電源７からの電力で補うように構成されている。
【００１２】
貯湯槽２には給湯管８が接続され、台所や浴槽に注湯するように構成されている。貯湯槽２からの湯は、循環配管や熱交換器などを図示していないが、床暖房や浴槽乾燥の熱源としても利用できる。図中９は市水を供給する給水管を示している。
【００１３】
貯湯槽２に、槽内に蓄えられた熱量を測定する蓄熱量センサとしての湯温を測定する湯温センサ１０が設けられ、この湯温センサ１０がコントローラ１１に接続されるとともにコントローラ１１が燃料電池１の発電電力量を制御する制御手段１２（図２参照）に接続されている。
【００１４】
コントローラ１１には、図２の制御系のブロック図に示すように、蓄熱量比較手段１３と発電電力量調整手段１４とが備えられ、更に、コントローラ１１に蓄熱量設定手段１５が接続されている。
【００１５】
蓄熱量設定手段１５では、貯湯槽２内の最大蓄熱量［上限貯湯温度（例えば、70℃）］よりも少ない蓄熱量［貯湯温度（例えば、60℃）］を設定するようになっている。
【００１６】
蓄熱量比較手段１３では、湯温センサ１０で測定される蓄熱量［湯の温度］と蓄熱量設定手段１５で設定された蓄熱量［設定貯湯温度（例えば、60℃）］とを比較し、測定蓄熱量［湯の温度］が設定蓄熱量［設定貯湯温度（例えば、60℃）］まで上昇したときに指令信号を出力するようになっている。
【００１７】
発電電力量調整手段１４では、蓄熱量比較手段１３からの指令信号に応答して制御手段１２による制御発電電力量が最大発電電力量（上限出力）よりも小さい設定電力量になるように調整するようになっている。ここでいう最大発電電力量とは、制御手段１２で出力する値の上限値であり、例えば、家電機器６の電力負荷がこの上限値より大きい値の場合は、燃料電池１は上限値の電力を出力し、一方、家電機器６の電力負荷が上限値より小さい値の場合は、燃料電池１は上限値まで出力せず、電力負荷に対応した値を出力することになる。
【００１８】
これにより、図３の貯湯槽温度と燃料電池上限出力との相関のグラフに示すように、燃料電池１を最大発電電力量（上限出力）Max で運転している状態で、貯湯槽２内の温度が設定蓄熱量［設定貯湯温度］TLになった段階で、制御発電電力量を、最大発電電力量（上限出力）Max より、順次、蓄熱量（貯湯槽温度）の上昇とともに減少させ、上限側の設定蓄熱量［上限側の設定貯湯温度］Max になった段階で、最大発電電力量を小さい設定電力量Min となるように変更することにより、貯湯槽２内の温度が最大蓄熱量［上限貯湯温度］になるまで運転する。このため、貯湯槽２内の温度が最大蓄熱量になるまでの時間を延長することができる。
【００１９】
図４は、本発明に係る家庭用燃料電池システムの第２実施例の制御系を示すブロック図であり、コントローラ１１に、第１の比較手段２１ａと第２の比較手段２１ｂとから成る蓄熱量比較手段２１と、直前判別手段２２と発電電力量調整手段２３とが備えられ、そのコントローラ１１に蓄熱量設定手段２４とピーク需要特定手段２５とが接続されている。
【００２０】
蓄熱量設定手段２４では、貯湯槽２内の最大蓄熱量［上限貯湯温度（例えば、70℃）］よりも少ない二段階の高蓄熱量［設定貯湯温度（例えば、60℃）］と低蓄熱量［設定貯湯温度（例えば、50℃）］を設定するようになっている。
【００２１】
ピーク需要特定手段２５では、給湯需要の経時的変化から、台所や浴槽への注湯など、給湯需要のピークとなる時間帯（例えば、午後６時から午後９時など）を特定するようになっている。
【００２２】
蓄熱量比較手段２１では、第１の比較手段２１ａにおいて、湯温センサ１０で測定される蓄熱量［測定湯温］と蓄熱量設定手段２４で設定された低蓄熱量［設定低貯湯温度（例えば、50℃）］とを比較し、測定蓄熱量［測定湯温］が設定低蓄熱量［設定低貯湯温度（例えば、50℃）］まで上昇したときに低蓄熱指令信号を出力するようになっている。
また、第２の比較手段２１ｂにおいて、湯温センサ１０で測定される蓄熱量［測定湯温］と蓄熱量設定手段２４で設定された高蓄熱量［設定高貯湯温度（例えば、60℃）］とを比較し、測定蓄熱量［測定湯温］が設定高蓄熱量［設定高貯湯温度（例えば、60℃）］まで上昇したときに高蓄熱指令信号を出力するようになっている。
【００２３】
直前判別手段２２では、第１の比較手段２１ａからの低蓄熱指令信号に応答してその信号出力時刻が前記ピーク需要特定手段で特定されているピークとなる時間帯の直前かどうかを判別し、直前のときに直前信号を出力するようになっている。
【００２４】
発電電力量調整手段２３では、第１の比較手段２１ａからの低蓄熱指令信号に応答して、直前判別手段２２からの直前信号の有無を判別し、前記直前信号が無いときには、制御手段１２による制御発電電力量が最大発電電力量（上限出力）よりも小さい設定電力量になるように調整するようになっている。
一方、直前信号が有るときには、低蓄熱指令信号が出力されても制御手段１２を作動させずに、高蓄熱指令信号に応答して、制御手段１２による制御発電電力量が最大発電電力量（上限出力）よりも小さい設定電力量になるように調整するようになっている。
【００２５】
これにより、図５の貯湯槽温度と燃料電池上限出力との相関のグラフに示すように、燃料電池１を最大発電電力量（上限出力）Max で運転している状態で、貯湯槽２内の蓄熱量［貯湯温度］が設定低蓄熱量［設定低貯湯温度］TLになった段階で、その時点が給湯需要のピークとなる時間帯の直前かどうかを判別し、直前であれば、そのまま最大発電電力量（上限出力）Max での運転を継続し、設定高蓄熱量［設定高貯湯温度（例えば、60℃）］THまで上昇したときに、制御発電電力量を、最大発電電力量（上限出力）Max より、順次、蓄熱量（貯湯槽温度）の上昇とともに減少させ、上限側の設定蓄熱量［上限側の設定貯湯温度］Max になった段階で、最大発電電力量を小さい設定電力量Min となるように変更することにより、貯湯槽２内の蓄熱量［貯湯温度］が最大蓄熱量［上限貯湯温度］になるまで運転する。このため、貯湯槽２内の蓄熱量［貯湯温度］を極力多くしながら、貯湯槽２内の蓄熱量［貯湯温度］が最大蓄熱量［上限貯湯温度］になるまでの時間を延長することができる。
【００２６】
そして、燃料電池１を最大発電電力量（上限出力）Max で運転している状態で、貯湯槽２内の蓄熱量［貯湯温度］が設定低蓄熱量［設定低貯湯温度］TLになった段階で、給湯需要のピークとなる時間帯の直前で無いときには、制御発電電力量を、最大発電電力量（上限出力）Max より、順次、蓄熱量（貯湯槽温度）の上昇とともに減少させ、上限側の設定蓄熱量［上限側の設定貯湯温度］Max になった段階で、最大発電電力量を小さい設定電力量Min となるように変更することにより、貯湯槽２内の温度が最大蓄熱量［上限貯湯温度］になるまで運転する。このため、貯湯槽２内の蓄熱量［貯湯温度］が最大蓄熱量［上限貯湯温度］になるまでの時間を延長することができる。
【００２７】
図６は、本発明に係る家庭用燃料電池システムの第３実施例のシステム構成図であり、第１実施例と異なるところは、次の通りである。
すなわち、貯湯槽２が成層貯湯タイプで構成されている。
【００２８】
貯湯槽２に、その高温状態の湯の位置（成層境界位置）を検知して蓄熱量を測定する蓄熱量センサとしての３個の第１，第２および第３の接触センサＴ１，Ｔ２，Ｔ３が設けられ、その第１，第２および第３の接触センサＴ１，Ｔ２，Ｔ３がコントローラ１１に接続されている。第１，第２および第３の接触センサＴ１，Ｔ２，Ｔ３として貯湯槽２内の湯の温度を測定する温度センサを用い、温度成層を形成する設定温度と比較し、測定温度が設定温度になったことを判別することにより高温状態の湯の位置（成層境界位置）を検知して蓄熱量を測定するように蓄熱量センサを構成しても良い。
【００２９】
コントローラ１１には、図７の制御系のブロック図に示すように、直前判別手段３１と発電電力量調整手段３２とが備えられ、そのコントローラ１１にピーク需要特定手段３３が接続されている。
【００３０】
ピーク需要特定手段３３では、給湯需要の経時的変化から、夕食や浴槽への注湯など、給湯需要のピークとなる時間帯（例えば、午後６時から午後９時など）を特定するようになっている。
【００３１】
第１および第２の接触センサＴ１，Ｔ２は、蓄熱量設定手段３４を構成するとともに蓄熱量センサを兼用するものである。
すなわち、第１の接触センサＴ１では、低蓄熱量として貯湯槽２内に、例えば、最大蓄熱量の30％が貯められた状態を設定するとともにその設定低蓄熱量を高温成層との接触によって測定できるようになっている。
第２の接触センサＴ２では、高蓄熱量として貯湯槽２内に、例えば、最大蓄熱量の60％が貯められた状態を設定するとともにその設定高蓄熱量を高温成層との接触によって測定できるようになっている。
【００３２】
これにより、図８の貯湯槽温度と燃料電池上限出力との相関のグラフに示すように、燃料電池１を最大発電電力量（上限出力）Max で運転している状態で、第１の接触センサＴ１がＯＮすることにより、貯湯槽２内の蓄熱量が設定低蓄熱量になったことを測定した段階で、その時点が給湯需要のピークとなる時間帯の直前かどうかを判別し、直前であれば、そのまま最大発電電力量（上限出力）Max での運転を継続する。そして、第２の接触センサＴ２がＯＮすることにより、貯湯槽２内の蓄熱量が設定高蓄熱量になったことを測定した段階で、制御発電電力量を、最大発電電力量（上限出力）Max より、電力量Ｐ２に減少させ、上限側の設定蓄熱量［上限側の設定貯湯温度］を検出する第３の接触センサＴ３がＯＮになった段階で、最大発電電力量を小さい設定電力量Min となるように変更することにより、貯湯槽２内の温度が最大蓄熱量［上限貯湯温度］になるまで運転する。このため、貯湯槽２内の蓄熱量を極力多くしながら、貯湯槽２内の蓄熱量が最大蓄熱量になるまでの時間を延長することができる。
【００３３】
一方、燃料電池１を最大発電電力量（上限出力）Max で運転している状態で、第１の接触センサＴ１がＯＮすることにより、貯湯槽２内の蓄熱量が設定低蓄熱量になったことを測定した段階で、その時点が給湯需要のピークとなるまでの時間帯の直前で無いときには、制御発電電力量を、最大発電電力量（上限出力）Max より、電力量Ｐ１に減少させ、さらに、第２の接触センサＴ２がＯＮすることにより、貯湯槽２内の蓄熱量が設定高蓄熱量になったことを測定した段階で、制御発電電力量を、電力量Ｐ１から電力量Ｐ２に減少させ、上限側の設定蓄熱量［上限側の設定貯湯温度］を検出する第３の接触センサＴ３がＯＮになった段階で、最大発電電力量を小さい設定電力量Min となるように変更することにより、貯湯槽２内の温度が最大蓄熱量［上限貯湯温度］になるまで運転する。このため、貯湯槽２内の蓄熱量が最大蓄熱量になるまでの時間を延長することができる。
【００３４】
【発明の効果】
以上の説明から明らかなように、請求項１に係る発明の家庭用燃料電池システムによれば、貯湯槽内に蓄えられた熱量が最大蓄熱量よりも低い設定蓄熱量になった時点で、燃料電池の発電電力量を減少させて排熱量の発生量を抑え、貯湯槽内の蓄熱量が満杯になるまでの時間を延ばすから、燃料電池を継続して運転できながら、燃料電池からの排熱の放熱を極力減少させて省エネルギー性を向上できる。
【００３５】
また、請求項２に係る発明の家庭用燃料電池システムによれば、給湯需要のピークとなる時間帯に近くないときには、貯湯槽内に蓄えられた熱量が最大蓄熱量よりも低い値に設定した高設定蓄熱量よりも更に低い低設定蓄熱量になった時点で、燃料電池の発電電力量を減少させて排熱量の発生量を抑え、貯湯槽内の蓄熱量が満杯になるまでの時間を延ばすから、燃料電池を継続して運転できながら、燃料電池からの排熱の放熱を極力減少させて省エネルギー性を向上できる。
一方、例えば、夕方で台所や浴槽に注湯するなど、給湯需要のピークとなる時間帯に近いときには、貯湯槽内に蓄えられた熱量が最大蓄熱量よりも低いが低設定蓄熱量よりも高い値に設定した高設定蓄熱量になった時点で、燃料電池の発電電力量を減少させて排熱量の発生量を抑え、貯湯槽内の蓄熱量が満杯になるまでの時間を延ばすから、燃料電池を継続して運転しながら、燃料電池からの排熱の放熱を極力減少させて省エネルギー性を向上でき、しかも、ピークとなる時間帯に近くないときよりも高い高設定蓄熱量で燃料電池の発電電力量を減少させるから、ピークとなる時間帯になったときに、極力多量の蓄熱量を確保しておけるようにでき、給湯需要のピークに対して良好に対応できる。
【図面の簡単な説明】
【図１】本発明に係る家庭用燃料電池システムの第１実施例のシステム構成図である。
【図２】制御系のブロック図である。
【図３】貯湯槽温度と燃料電池上限出力との相関を示すグラフである。
【図４】本発明に係る家庭用燃料電池システムの第１実施例の制御系のブロック図である。
【図５】貯湯槽温度と燃料電池上限出力との相関を示すグラフである。
【図６】本発明に係る家庭用燃料電池システムの第３実施例のシステム構成図である。
【図７】制御系のブロック図である。
【図８】貯湯槽温度と燃料電池上限出力との相関を示すグラフである。
【符号の説明】
１…燃料電池
２…貯湯槽
１０…湯温センサ
１２…制御手段
１３，２１…蓄熱量比較手段
１４，２３，３２…発電電力量調整手段
１５，２４，３４…蓄熱量設定手段
２２，３１…直前判別手段
２５，３３…ピーク需要特定手段[0001]
BACKGROUND OF THE INVENTION
The present invention stores a hot water heated by exhaust heat from a fuel cell that generates electricity and heat in a hot water storage tank, and includes a control means for controlling the amount of electric power generated by the fuel cell. About the system.
[0002]
[Prior art]
In this type of household fuel cell system, heat generated according to the power generated by the fuel cell is temporarily stored in a hot water storage tank and supplied in accordance with hot water supply demand. When there is much demand for hot water supply and the amount of heat stored in the hot water storage tank is insufficient, hot water is replenished by an auxiliary heating device such as a separately installed boiler.
[0003]
[Problems to be solved by the invention]
However, generally, so-called main heat follow-up operation, which controls the amount of generated power according to the power used in general, is less demand for hot water supply, when hot water of the upper limit temperature is stored in the hot water tank full, Electricity generation is continued while dissipating the exhaust heat from the fuel cell, and there is a drawback that the efficiency of exhaust heat recovery decreases and the energy saving performance decreases.
[0004]
In order to avoid heat dissipation, it was considered to provide a large hot water storage tank, but the initial cost increased, and the amount of heat released from the hot water storage tank and the equipment attached thereto was likely to cause energy loss. There was a drawback that the energy saving performance was lowered.
[0005]
The present invention has been made in view of such circumstances, and the invention according to claim 1 saves energy by reducing the heat radiation of exhaust heat from the fuel cell as much as possible while continuously operating the fuel cell. The invention according to claim 2 can improve the energy saving by reducing the heat radiation of the exhaust heat from the fuel cell as much as possible while continuously operating the fuel cell. At the same time, it aims to be able to cope with the peak of hot water demand.
[0006]
[Means for Solving the Problems]
In order to achieve the above-described object, the invention according to claim 1
A fuel cell that generates electricity and heat;
A hot water storage tank for storing hot water heated by exhaust heat from the fuel cell;
In a household fuel cell system comprising a control means for controlling the amount of power generated by the fuel cell,
A heat storage sensor for measuring the amount of heat stored in the hot water tank;
A heat storage amount setting means for setting a heat storage amount lower than the maximum heat storage amount in the hot water storage tank;
A heat storage amount comparison unit that compares the heat storage amount measured by the heat storage amount sensor with the heat storage amount set by the heat storage amount setting unit, and outputs a command signal when the measured heat storage amount rises to the set heat storage amount;
And a generated power amount adjusting means for adjusting the control generated power amount by the control means to be a set power amount smaller than the maximum generated power amount in response to the command signal.
[0007]
In order to achieve the above-described object, the invention according to claim 2
A fuel cell that generates electricity and heat;
A hot water storage tank for storing hot water heated by exhaust heat from the fuel cell;
In a household fuel cell system comprising a control means for controlling the amount of power generated by the fuel cell,
A heat storage sensor for measuring the amount of heat stored in the hot water tank;
A heat storage amount setting means for setting a high heat storage amount and a low heat storage amount in two stages less than the maximum heat storage amount in the hot water storage tank,
Compare the heat storage amount measured by the heat storage amount sensor with the low heat storage amount set by the heat storage amount setting means and the high heat storage amount, and when the measured heat storage amount rises to the set low heat storage amount, the low heat storage command signal , A heat storage amount comparison means for outputting a high heat storage amount command signal when the measured heat storage amount rises to the set high heat storage amount,
A peak demand specifying means for specifying a time zone in which the hot water demand is peaked from a change in hot water demand over time,
In response to the low heat storage command signal, it is determined whether or not the signal output time is immediately before the peak time period specified by the peak demand specifying means, and immediately before determining means for outputting a previous signal immediately before When,
In response to the low heat storage command signal, the presence / absence of the immediately preceding signal from the immediately preceding determining unit is determined, and when there is no preceding signal, the control power generation amount controlled by the control unit is smaller than the maximum generated power amount When the immediately preceding signal is present, the control means is not operated, and the control generated power amount by the control means is smaller than the maximum generated power amount in response to the high heat storage command signal And a generated power amount adjusting means for adjusting to a set power amount.
[0008]
[Action]
According to the configuration of the domestic fuel cell system of the invention according to claim 1, when the amount of heat stored in the hot water storage tank increases, when the set heat storage amount is lower than the maximum heat storage amount, The amount of generated power of the battery can be adjusted to be a set power amount that is smaller than the maximum generated power amount, and the amount of heat generated in the hot water tank can be extended by suppressing the amount of heat generated.
[0009]
Further, according to the configuration of the domestic fuel cell system of the invention according to claim 2, when the hot water supply demand is taken into consideration, it is stored in the hot water storage tank when it is not close to the time zone when the hot water supply demand is peaked. When the amount of heat increases, when the low set heat storage amount is lower than the high set heat storage amount set to a value lower than the maximum heat storage amount, the power generation amount of the fuel cell is set to be less than the maximum power generation amount. It is possible to adjust the amount of electric power to be small and reduce the amount of generated heat to extend the time until the amount of heat stored in the hot water tank is full.
On the other hand, when the amount of heat stored in the hot water tank is increasing when it is close to the peak time of hot water demand, a high setting that is lower than the maximum heat storage amount but higher than the low heat storage amount is set. When the amount of heat storage is reached, the power generation amount of the fuel cell is adjusted to a set power amount that is smaller than the maximum power generation amount, and the amount of waste heat generation is suppressed, and the heat storage amount in the hot water tank is full. The amount of heat storage can be secured as much as possible when the peak time zone is reached.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a system configuration diagram of a first embodiment of a domestic fuel cell system according to the present invention, in which a fuel cell 1 for generating electricity and heat and a hot water tank 2 are circulated with a circulation pump 3 interposed therebetween. Connected via a pipe 4, the water is heated by exhaust heat generated in the fuel cell 1 to obtain hot water, and the hot water is stored in the hot water tank 2.
[0011]
The home electric appliance 6 as a load is connected to the electric power output line 5 from the fuel cell 1, and the commercial power source 7 is linked to the electric power output line 5 to supply the generated electric power from the fuel cell 1 to the electric home appliance 6. The shortage of power is supplemented with power from the commercial power source 7.
[0012]
A hot water supply pipe 8 is connected to the hot water tank 2 and is configured to pour hot water into a kitchen or a bathtub. The hot water from the hot water tank 2 can be used as a heat source for floor heating and bathtub drying, although a circulation pipe and a heat exchanger are not shown. In the figure, reference numeral 9 denotes a water supply pipe for supplying city water.
[0013]
The hot water storage tank 2 is provided with a hot water temperature sensor 10 for measuring the hot water temperature as a heat storage amount sensor for measuring the amount of heat stored in the tank. The hot water temperature sensor 10 is connected to the controller 11 and the controller 11 is a fuel. It is connected to the control means 12 (refer FIG. 2) which controls the electric power generation amount of the battery 1. FIG.
[0014]
As shown in the block diagram of the control system in FIG. 2, the controller 11 includes a heat storage amount comparison unit 13 and a generated power amount adjustment unit 14, and a heat storage amount setting unit 15 is connected to the controller 11. .
[0015]
The heat storage amount setting means 15 sets a heat storage amount [hot water storage temperature (for example, 60 ° C.)] smaller than the maximum heat storage amount [upper limit hot water storage temperature (for example, 70 ° C.)] in the hot water tank 2.
[0016]
The heat storage amount comparison means 13 compares the heat storage amount [hot water temperature] measured by the hot water temperature sensor 10 with the heat storage amount [set hot water storage temperature (for example, 60 ° C.)] set by the heat storage amount setting means 15. A command signal is output when the measured heat storage amount [hot water temperature] rises to the set heat storage amount [set hot water storage temperature (for example, 60 ° C.)].
[0017]
In the generated power amount adjusting means 14, the control generated power amount by the control means 12 is adjusted so as to be smaller than the maximum generated power amount (upper limit output) in response to the command signal from the heat storage amount comparing means 13. It is like that. The maximum amount of generated power here is the upper limit value of the value output by the control means 12. For example, when the power load of the home appliance 6 is larger than the upper limit value, the fuel cell 1 On the other hand, when the electric power load of the home appliance 6 is a value smaller than the upper limit value, the fuel cell 1 does not output the upper limit value, but outputs a value corresponding to the electric power load.
[0018]
As a result, as shown in the graph of the correlation between the hot water tank temperature and the fuel cell upper limit output in FIG. 3, the fuel cell 1 is operated in the maximum electric power generation amount (upper limit output) Max, When the temperature reaches the set heat storage amount [set hot water temperature] TL, the control power generation amount is gradually decreased from the maximum power generation amount (upper limit output) Max as the heat storage amount (hot water tank temperature) increases, and the upper limit is reached. When the set heat storage amount on the side [the set hot water temperature on the upper limit side] Max is reached, the maximum generated power amount is changed to a small set power amount Min, so that the temperature in the hot water storage tank 2 becomes the maximum heat storage amount [ Operate until the maximum hot water storage temperature is reached. For this reason, the time until the temperature in the hot water tank 2 reaches the maximum heat storage amount can be extended.
[0019]
FIG. 4 is a block diagram showing a control system of a second embodiment of the household fuel cell system according to the present invention, in which the controller 11 stores a heat storage amount comprising a first comparison means 21a and a second comparison means 21b. The comparison means 21, the immediately preceding determination means 22 and the generated power amount adjustment means 23 are provided, and the heat storage amount setting means 24 and the peak demand specifying means 25 are connected to the controller 11.
[0020]
In the heat storage amount setting means 24, two stages of high heat storage amounts [set hot water storage temperature (eg, 60 ° C.)] less than the maximum heat storage amount in the hot water tank 2 [upper hot water storage temperature (eg, 70 ° C.)] and low heat storage amounts [Set hot water storage temperature (for example, 50 ° C.)] is set.
[0021]
The peak demand specifying means 25 specifies a time zone (for example, from 6:00 pm to 9:00 pm, etc.) at which the hot water supply demand peaks, such as pouring water into the kitchen or bathtub, from the change in hot water demand over time. ing.
[0022]
In the heat storage amount comparison means 21, in the first comparison means 21a, the heat storage amount [measured hot water temperature] measured by the hot water temperature sensor 10 and the low heat storage amount set by the heat storage amount setting means 24 [set low hot water storage temperature (for example, , 50 ℃)], and when the measured heat storage amount [measured hot water temperature] rises to the set low heat storage amount [set low hot water storage temperature (for example, 50 ℃)], the low heat storage command signal is output. ing.
Further, in the second comparison means 21b, the heat storage amount [measured hot water temperature] measured by the hot water temperature sensor 10 and the high heat storage amount [set high hot water storage temperature (for example, 60 ° C.)] set by the heat storage amount setting means 24. And a high heat storage command signal is output when the measured heat storage amount [measured hot water temperature] rises to a set high heat storage amount [set high hot water storage temperature (for example, 60 ° C.)].
[0023]
The immediately preceding determining means 22 determines whether the signal output time is immediately before the peak time period specified by the peak demand specifying means in response to the low heat storage command signal from the first comparing means 21a, The immediately preceding signal is output immediately before.
[0024]
In response to the low heat storage command signal from the first comparing means 21a, the generated power amount adjusting means 23 determines the presence or absence of the immediately preceding signal from the immediately preceding determining means 22, and when there is no immediately preceding signal, the control means 12 The control power generation amount is adjusted so as to be a set power amount smaller than the maximum power generation amount (upper limit output).
On the other hand, when there is an immediately preceding signal, the control means 12 does not operate even if a low heat storage command signal is output, and the control generated power amount by the control means 12 is the maximum generated power amount (upper limit) in response to the high heat storage command signal. Adjustment is made so that the set power amount is smaller than (output).
[0025]
As a result, as shown in the graph of the correlation between the hot water tank temperature and the fuel cell upper limit output in FIG. 5, the fuel cell 1 is operated in the maximum electric power generation amount (upper limit output) Max, When the heat storage amount [hot water storage temperature] reaches the set low heat storage amount [setting low hot water storage temperature] TL, it is determined whether the time is immediately before the peak time of hot water supply demand. Continued operation at the maximum power generation amount (upper limit output) Max, and when the set high heat storage amount [set high hot water storage temperature (eg, 60 ° C)] TH rises to the control power generation amount, the maximum generation power amount (upper limit Output) From Max, reduce the heat storage amount (hot water storage tank temperature) sequentially, and at the stage where the upper limit set heat storage amount [upper limit set hot water temperature] Max is reached, the maximum generated power amount is set to a smaller set power amount. By changing to Min, the amount of heat stored in the hot water tank 2 [ Hot water temperature] is operated to the maximum heat storage amount Max hot water storage temperature. For this reason, it is possible to extend the time until the heat storage amount [hot water temperature] in the hot water tank 2 reaches the maximum heat storage amount [upper limit hot water temperature] while increasing the heat storage amount [hot water temperature] in the hot water tank 2 as much as possible. it can.
[0026]
Then, in a state where the fuel cell 1 is operated at the maximum power generation amount (upper limit output) Max, the heat storage amount [hot water temperature] in the hot water tank 2 becomes the set low heat storage amount [set low hot water temperature] TL. However, when it is not just before the peak time of hot water supply demand, the control power generation amount is gradually decreased from the maximum power generation amount (upper limit output) Max as the heat storage amount (hot water tank temperature) is increased. When the set heat storage amount [upper limit set hot water temperature] Max is reached, the maximum generated power amount is changed to become a smaller set power amount Min, so that the temperature in the hot water storage tank 2 becomes the maximum heat storage amount [upper limit Operate until hot water storage temperature is reached. For this reason, the time until the heat storage amount [hot water temperature] in the hot water tank 2 reaches the maximum heat storage amount [upper limit hot water temperature] can be extended.
[0027]
FIG. 6 is a system configuration diagram of a third embodiment of the household fuel cell system according to the present invention. The differences from the first embodiment are as follows.
That is, the hot water tank 2 is configured as a stratified hot water type.
[0028]
Three first, second and third contact sensors T1, T2 and T3 as heat storage amount sensors for measuring the amount of heat storage by detecting the position (stratification boundary position) of hot water in the hot water storage tank 2 The first, second and third contact sensors T1, T2, T3 are connected to the controller 11. A temperature sensor that measures the temperature of hot water in the hot water tank 2 is used as the first, second, and third contact sensors T1, T2, and T3, and the measured temperature is compared with the set temperature that forms the temperature stratification. The heat storage amount sensor may be configured to detect the position of the hot water in the high temperature state (stratification boundary position) and measure the heat storage amount by determining that it has become.
[0029]
As shown in the block diagram of the control system in FIG. 7, the controller 11 is provided with immediately preceding determining means 31 and generated power amount adjusting means 32, and a peak demand specifying means 33 is connected to the controller 11.
[0030]
The peak demand specifying means 33 specifies a time zone (for example, from 6:00 pm to 9:00 pm, etc.) at which the hot water supply demand is peaked, such as supper or pouring into a bathtub, from the change in hot water demand over time. ing.
[0031]
The first and second contact sensors T1, T2 constitute the heat storage amount setting means 34 and also serve as the heat storage amount sensor.
That is, in the first contact sensor T1, for example, a state in which 30% of the maximum heat storage amount is stored in the hot water storage tank 2 as a low heat storage amount is set and the set low heat storage amount is measured by contact with high temperature stratification. It can be done.
In the second contact sensor T2, for example, a state where 60% of the maximum heat storage amount is stored in the hot water storage tank 2 as a high heat storage amount can be set and the set high heat storage amount can be measured by contact with high temperature stratification. It has become.
[0032]
Accordingly, as shown in the graph of the correlation between the hot water tank temperature and the fuel cell upper limit output in FIG. 8, the first contact sensor is operated in a state where the fuel cell 1 is operated at the maximum generated power (upper limit output) Max. When T1 is turned on, when it is measured that the heat storage amount in the hot water storage tank 2 has reached the set low heat storage amount, it is determined whether or not that time is immediately before the peak time of hot water supply demand. If there is, continue operation at the maximum generated power (maximum output) Max. Then, when the second contact sensor T2 is turned on and the heat storage amount in the hot water tank 2 is measured to be the set high heat storage amount, the control power generation amount is set to the maximum power generation amount (upper limit output). From Max, when the third contact sensor T3 for detecting the upper limit set heat storage amount [the upper set hot water storage temperature] is turned ON, the maximum generated power amount is set to a smaller set power amount. By changing to Min, the operation is continued until the temperature in the hot water storage tank 2 reaches the maximum heat storage amount [upper limit hot water storage temperature]. For this reason, the time until the heat storage amount in the hot water tank 2 becomes the maximum heat storage amount can be extended while increasing the heat storage amount in the hot water tank 2 as much as possible.
[0033]
On the other hand, when the first contact sensor T1 is turned on while the fuel cell 1 is operated at the maximum generated power amount (upper limit output) Max, the heat storage amount in the hot water tank 2 becomes the set low heat storage amount. In the stage where the measured value is not immediately before the peak time of hot water supply demand, the control power generation amount is reduced from the maximum power generation amount (upper limit output) Max to the power amount P1, Further, when the second contact sensor T2 is turned ON, the amount of heat generated in the hot water tank 2 is measured to be the set high heat storage amount, and the control power generation amount is changed from the power amount P1 to the power amount P2. When the third contact sensor T3 that detects the upper limit side set heat storage amount [the upper limit side set hot water temperature] is turned on, the maximum generated power amount is changed to a smaller set power amount Min. Therefore, the temperature in the hot water tank 2 is the maximum heat storage It operated until the Maximum hot water storage temperature. For this reason, time until the heat storage amount in the hot water storage tank 2 becomes the maximum heat storage amount can be extended.
[0034]
【The invention's effect】
As is clear from the above description, according to the domestic fuel cell system of the invention according to claim 1, when the amount of heat stored in the hot water storage tank becomes a set heat storage amount lower than the maximum heat storage amount, By reducing the amount of power generated by the battery to reduce the amount of generated heat and extending the time until the amount of heat stored in the hot water tank becomes full, the exhaust heat from the fuel cell can be maintained while the fuel cell can continue to operate. The heat dissipation can be reduced as much as possible to improve energy saving.
[0035]
Moreover, according to the domestic fuel cell system of the invention according to claim 2, when it is not close to the time zone when the hot water supply demand is peak, the amount of heat stored in the hot water storage tank is set to a value lower than the maximum heat storage amount. When the low set heat storage amount is lower than the high set heat storage amount, the amount of power generated by the fuel cell is reduced to reduce the amount of generated heat, and the time until the heat storage amount in the hot water tank becomes full Therefore, while continuing to operate the fuel cell, the heat dissipation of the exhaust heat from the fuel cell can be reduced as much as possible to improve the energy saving performance.
On the other hand, the amount of heat stored in the hot water tank is lower than the maximum heat storage amount but higher than the low heat storage amount when it is close to the peak time of hot water supply demand, for example, pouring into the kitchen or bathtub in the evening When the high heat storage amount set to the value is reached, the amount of power generated by the fuel cell is reduced to reduce the amount of generated heat, and the time until the heat storage amount in the hot water tank is full is increased. While continuously operating the battery, the heat dissipation from the fuel cell can be reduced as much as possible to improve energy savings, and the fuel cell has a higher heat storage capacity than when it is not close to the peak time zone. Since the amount of generated power is reduced, it is possible to secure as much heat storage as possible when the peak time period is reached, and it is possible to cope with the peak demand for hot water supply.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of a first embodiment of a household fuel cell system according to the present invention.
FIG. 2 is a block diagram of a control system.
FIG. 3 is a graph showing a correlation between hot water tank temperature and fuel cell upper limit output.
FIG. 4 is a block diagram of a control system of a first embodiment of a household fuel cell system according to the present invention.
FIG. 5 is a graph showing the correlation between hot water tank temperature and fuel cell upper limit output.
FIG. 6 is a system configuration diagram of a third embodiment of a household fuel cell system according to the present invention.
FIG. 7 is a block diagram of a control system.
FIG. 8 is a graph showing the correlation between hot water tank temperature and fuel cell upper limit output.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Fuel cell 2 ... Hot water storage tank 10 ... Hot water temperature sensor 12 ... Control means 13, 21 ... Heat storage amount comparison means 14, 23, 32 ... Electric power generation amount adjustment means 15, 24, 34 ... Heat storage amount setting means 22, 31 ... Immediately determining means 25, 33 ... Peak demand specifying means

Claims

A fuel cell that generates electricity and heat;
A hot water storage tank for storing hot water heated by exhaust heat from the fuel cell;
In a household fuel cell system comprising a control means for controlling the amount of power generated by the fuel cell,
A heat storage sensor for measuring the amount of heat stored in the hot water tank;
A heat storage amount setting means for setting a heat storage amount lower than the maximum heat storage amount in the hot water storage tank;
A heat storage amount comparison unit that compares the heat storage amount measured by the heat storage amount sensor with the heat storage amount set by the heat storage amount setting unit, and outputs a command signal when the measured heat storage amount rises to the set heat storage amount;
A fuel cell for home use, comprising: a power generation amount adjusting means for adjusting a control power generation amount by the control means to be a set power amount smaller than a maximum power generation amount in response to the command signal system.

A fuel cell that generates electricity and heat;
A hot water storage tank for storing hot water heated by exhaust heat from the fuel cell;
In a household fuel cell system comprising a control means for controlling the amount of power generated by the fuel cell,
A heat storage sensor for measuring the amount of heat stored in the hot water tank;
A heat storage amount setting means for setting a high heat storage amount and a low heat storage amount in two stages less than the maximum heat storage amount in the hot water storage tank,
Compare the heat storage amount measured by the heat storage amount sensor with the low heat storage amount set by the heat storage amount setting means and the high heat storage amount, and when the measured heat storage amount rises to the set low heat storage amount, the low heat storage command signal , A heat storage amount comparison means for outputting a high heat storage amount command signal when the measured heat storage amount rises to the set high heat storage amount,
A peak demand specifying means for specifying a time zone in which the hot water demand is peaked from a change in hot water demand over time,
In response to the low heat storage command signal, it is determined whether or not the signal output time is immediately before the peak time period specified by the peak demand specifying means, and immediately before determining means for outputting a previous signal immediately before When,
In response to the low heat storage command signal, the presence / absence of the immediately preceding signal from the immediately preceding determining unit is determined, and when there is no preceding signal, the control power generation amount controlled by the control unit is smaller than the maximum generated power amount When the immediately preceding signal is present, the control means is not operated, and the control generated power amount by the control means is smaller than the maximum generated power amount in response to the high heat storage command signal A household fuel cell system comprising a generated power amount adjusting means for adjusting to a set power amount.