JP3968643B2

JP3968643B2 - Solar water heater

Info

Publication number: JP3968643B2
Application number: JP2002112941A
Authority: JP
Inventors: 裕和大渡; 裕三山本
Original assignee: Noritz Corp
Current assignee: Noritz Corp
Priority date: 2002-04-16
Filing date: 2002-04-16
Publication date: 2007-08-29
Anticipated expiration: 2022-04-16
Also published as: JP2003307351A

Description

【０００１】
【発明の属する技術分野】
本発明は、循環ポンプの作動により蓄熱槽内の水を太陽熱集熱器（コレクタ）との間で強制循環させて加熱することにより太陽熱を温水として蓄熱し、この温水を給湯器等の補助熱源機を介して給湯栓に送り、給湯に利用させるために用いられる太陽熱利用温水装置に関する。
【０００２】
【従来の技術】
従来より、この種の太陽熱利用温水装置による集熱運転制御として、次に示すような比例運転制御が一般に行われている。すなわち、図８に示す循環ポンプ７０を連続運転させ、コレクタ３の温度（表面温度）又はコレクタ３の出口の温水温度がある設定温度（例えば６０〜７５℃）になるように、上記循環ポンプ７０の循環流量を変更制御するというものである。この場合には、上記循環ポンプ７０として可変流量ポンプを用い、例えばその回転数を変更制御することにより吐出流量、つまり循環流量が変更制御される。なお、コレクタ３の表面温度は、太陽の日射を受けて加熱される一方、内側の循環流水との熱交換により熱が奪われるため、太陽熱により昇温されて蓄熱槽に戻される温水温度をほぼ表すことになる。
【０００３】
また、太陽熱利用温水装置により蓄熱槽２内に蓄熱された温水は、蓄熱槽２から取り出されて給湯に供することが通常行われているが、その際に蓄熱槽２内の温水が給湯として要求される温度よりも低い場合もある。このため、一般的には、図８に示すように蓄熱槽２と給湯栓との間に補助熱源機（例えば給湯器）１００を介装し、蓄熱槽２から取り出された温水を補助熱源機１００で加熱した上で下流端の給湯栓に給湯するようにされている。
【発明が解決しようとする課題】
ところが、太陽の日射量は天候の状況に応じて様々に変化するため、上記の集熱運転制御によると日射量が少ない場合には設定温度の温水を蓄熱槽２に蓄熱するまでに長時間を要する上に、集熱効率、つまり太陽熱の利用効率も低下することになる。加えて、それまでに給湯使用が行われると上記補助熱源機１００による加熱を追加する必要がありその加熱のためのエネルギー（化石燃料エネルギー又は電気エネルギー）消費がより多く必要になるという不都合がある。
【０００４】
すなわち、太陽が昇っても、上記コレクタ３の温度が設定温度ぎりぎりまでしか昇温しないか、設定温度前後程度にしか昇温しない程度の日射量であると、設定温度までに昇温させるために循環流量は極端に少なく制御されてしまい、集熱効率は極めて低下する上に、蓄熱までに長時間を要することにもなる。特に日の出からの朝の間にこのような不都合が発生し易い。
【０００５】
本発明は、このような事情に鑑みてなされたものであり、その目的とするところは、給湯用に要求される温度の温水をより短時間で蓄熱させ得ると共に、その蓄熱を天候の状況に応じて効率よく行い得る太陽熱利用温水装置を提供することにある。
【０００６】
【課題を解決するための手段】
上記目的を達成するために、循環ポンプの作動により蓄熱槽内の底部の水を太陽熱集熱器に供給しこの太陽熱集熱器により加熱された温水を上記蓄熱槽の頂部に戻すように強制循環する集熱運転を行い、上記蓄熱槽に対し太陽熱を温水として蓄熱させるように構成された太陽熱利用温水装置を対象として、以下の種々の特定事項を備えることとした。
【０００７】
すなわち、請求項１に係る発明では、上記太陽熱集熱器が受ける日射量を検出する日射量検出手段と、上記太陽熱集熱器から蓄熱槽の頂部に戻されることになる温水の温度を検出する第１温度検出手段と、この第１温度検出手段による検出温度が目標温度になるように上記循環ポンプを作動することにより集熱運転制御を行う集熱運転制御手段とを備えることとする。そして、上記集熱運転制御手段として、上記日射量検出手段からの検出日射量に基づいて目標温度を設定する目標温度設定部を有するものとし、この目標温度設定部として、上記検出日射量との関係で定まる蓄熱温度よりも低い温度を目標温度としてまず設定し、以後、その目標温度を上記蓄熱温度に又は上記蓄熱温度までの範囲の高温側温度に段階的に変更設定する構成とする。
【０００８】
なお、上記の「集熱運転制御」としては、循環ポンプを連続運転させてその循環ポンプによる循環流量を変更調整することにより上記検出温度が目標温度になるようにさせる比例運転制御を行っても、循環ポンプを定流量でＯＮ・ＯＦＦ間欠運転させることにより上記検出温度が目標温度になるようにさせるＯＮ・ＯＦＦ運転制御を行っても、いずれでもよい。この点は、以下の請求項２において同様である。
【０００９】
上記請求項１によれば、目標温度設定部によって検出日射量に対応する蓄熱温度よりも低い温度、すなわち、現在の日射量ならば通常の集熱効率での循環流量にて加熱し得る加熱後の温水温度よりも低い温度が集熱運転制御での目標温度としてまず設定されるため、このような目標温度により集熱運転制御（循環ポンプの作動制御）を行えば、上記蓄熱温度を最初から目標温度として設定する場合よりも短時間で蓄熱することが可能になる上に、太陽熱を高効率で利用することも可能になる。例えば上記の比例運転制御を実行する場合であると、例えば目標温度を最初から７５℃とするよりも最初は４０℃とする方が循環流量がより多くなり、あるいは、上記のＯＮ・ＯＦＦ運転制御を実行する場合であると循環ポンプのＯＮ作動時間がより長くなるため、上記目標温度の温水を蓄熱槽に短時間で蓄熱し得る上に、太陽熱の利用効率も高くなる。加えて、低温側の目標温度の温水が蓄熱槽に早期に蓄熱されるため、給湯に供するために補助熱源機で加熱するにしても、その加熱のためのエネルギー消費の節減が図られる。
【００１１】
以上のように、まず、検出日射量に応じて定まる蓄熱温度よりも低い温度が設定された目標温度に基づき集熱運転制御が行われ、その目標温度の温水が蓄熱槽に蓄熱されれば、次に、より高温側の温度に変更設定された目標温度に基づく集熱運転制御が行われ、より高温側の温度の温水が蓄熱槽に蓄熱される、というように、蓄熱槽への蓄熱が段階的に行われる。このため、上述の作用を得た上で、さらに、より高温側の温水の蓄熱をも続行させることが可能になる。これにより、太陽熱の利用効率という観点において、より高温側までの蓄熱を天候の状況に応じて効率よく行い得ることになる。
【００１２】
ここで、上記目標温度設定部による目標温度の変更設定は、上記蓄熱温度よりも低い温度を第１目標温度として設定した後、上記蓄熱温度を第２目標温度として変更設定しても、あるいは、上記第１目標温度と蓄熱温度との中間温度を第２目標温度として変更設定しても、いずれでもよい。また、後者の場合に、上記蓄熱温度を第３目標温度としてさらに変更設定しても、あるいは、より高温側の中間温度を第３もしくは第４目標温度として段階的に変更設定して最終段階で上記蓄熱温度を目標温度として変更設定しても、いずれでもよい。なお、このような段階的変更設定については、次の請求項２においても同様に採用し得る。また、上記の第１目標温度としては、蓄熱槽から太陽熱集熱器に供給される蓄熱槽底部の温度と、検出日射量との関係で定めてもよいが、給湯用に要求される常用温度（例えば４０℃）を設定することが好ましい。このようにすると、給湯側に補助熱源機が介装されている場合には、その補助熱源機の加熱作動なしに蓄熱槽に蓄熱された温水をそのまま給湯させることが可能になり、補助熱源機での加熱のためのエネルギー消費を省略することが可能になる。
【００１３】
請求項２に係る発明では、上記太陽熱燃焼器が受ける日射量を検出する日射量検出手段と、上記太陽熱集熱器から蓄熱槽の頂部に戻されることになる温水の温度を検出する第１温度検出手段と、この第１温度検出手段による検出温度が目標温度になるように上記循環ポンプを作動することにより集熱運転制御を行う集熱運転制御手段とを備えこととする。この場合の集熱運転制御手段として、計時により現在の季節に関する情報を出力する季節情報出力部と、上記日射量検出手段からの検出日射量又は上記季節情報出力部からの季節情報に基づいて目標温度を設定する目標温度設定部とを有するものとする。そして、上記目標温度設定部として、上記検出日射量との関係で定まる蓄熱温度よりも低い温度を目標温度としてまず設定し、以後、その目標温度を上記季節情報出力部からの季節情報に応じて予め定めた高温側温度に変更設定する構成とする。
【００１４】
この請求項２によれば、請求項２による作用の全てが得られる上に、目標温度設定部による目標温度の変更設定を、現在の季節情報を加味して変更させることが可能になる。このため、まずは低温側の目標温度の温水を早期に蓄熱した上で、日射量の季節変動特性に応じたより高温側の温水の蓄熱を効率よく続行させることが可能になる。上記の「季節情報」とは１月・２月・３月…というような月別の情報であっても、春・夏・秋・冬というような四季についての情報であってもよい。そして、月別であれば、第２目標温度として例えば１２月〜２月には５５℃を、６月〜８月には６５℃を、他の月には６０℃をというようにそれぞれ変更設定し、四季別であれば、第２目標温度として冬期には５５℃を、夏期であれば６５℃を、春期もしくは秋期であれば６０℃をというようにそれぞれ変更設定すればよい。このようにすると、例えば冬期であっても画一的に６０℃を第２目標温度として設定する場合に比して、実際の天候もしくは日射状況により対応させた蓄熱が可能になる。
【００１５】
上記の請求項１又は請求項２の太陽熱利用温水装置において、循環ポンプの循環流量を変更調整しつつ連続運転させる作動制御を行う場合には次のようにすればよい。すなわち、上記循環ポンプを可変流量ポンプにより構成し、上記集熱運転制御手段として、上記循環ポンプによる作動制御流量を、上記蓄熱槽内の底部から頂部までの間に温度差のある２以上の層が形成される低流量範囲として予め設定した成層流量範囲内に制限しつつ、上記検出温度が目標温度になるように比例制御により変更調整する構成とすればよい（請求項３）。循環ポンプの作動制御流量を上記成層流量範囲内に制限することにより、蓄熱槽内には底部から頂部までの間に温度差のある２以上の層が成層されることになる。すなわち、太陽熱集熱器で加熱された温水が蓄熱槽に戻されても、低流量であるため蓄熱槽内はかき回されることなく上記加熱後の温水が頂部から順に蓄積されることになる。このため、集熱運転開始後、蓄熱槽の底部はまだ低温であっても、蓄熱槽の頂部には目標温度の温水が早期に確保され、目標温度の温水の早期利用が可能となる。
【００１６】
上記の請求項１〜請求項３のいずれかの太陽熱利用温水装置においては、上記蓄熱槽の底部の水又は温水の温度を検出する第２温度検出手段をさらに備え、上記集熱運転制御手段として、集熱運転の開始により、第１温度検出手段及び上記第２温度検出手段による両検出温度の差の如何に応じて上記循環ポンプを所定流量でＯＮ・ＯＦＦの間欠作動させる温度差ＯＮ・ＯＦＦ運転制御をまず実行し、その後に、目標温度に基づく循環ポンプの作動制御を開始する構成を追加するようにしてもよい（請求項４）。この場合には、日射量が不十分であるときにおいても、まずは上記温度差ＯＮ・ＯＦＦ運転制御を開始させることにより、目標温度よりは低温ではあっても太陽熱を少しでも蓄熱することが可能になる。
【００１７】
上記の請求項１〜請求項４のいずれかの太陽熱利用温水装置で用いる日射量検出手段としては、種々のものを採用することができる。例えば、上記日射量検出手段として、太陽熱集熱器の表面に配設された太陽電池を備え、この太陽電池の発電量に基づいて日射量を推定して検出する構成としてもよい（請求項５）。この場合には、後述の構成と比して日射量を直接的に検出して把握することが可能になり、集熱制御をより適切に実行させ得る。
【００１８】
あるいは、上記循環ポンプの作動による循環流量を検出する流量検出手段と、上記蓄熱槽の底部の水又は温水の温度を検出する第２温度検出手段をさらに備え、上記日射量検出手段として、上記流量検出手段による検出流量と、上記第１及び第２の両温度検出手段による両検出温度の温度差との乗算により得られる集熱量に基づいて、そのときの日射量を推定して検出する構成を採用するようにしてもよい（請求項６）。この場合には、日射量検出のための特別なセンサ等を設置することなく、太陽熱利用温水装置に対し他の用途のために通常設けられている検出手段を利用して演算により日射量を検出し得ることになる。
【００１９】
なお、上記の請求項１〜請求項６のいずれかの太陽熱利用温水装置における第１温度検出手段としては、強制循環中の太陽熱集熱器の表面温度もしくは内部の循環流水の温度、あるいは、上記太陽熱集熱器から蓄熱槽の頂部に戻される温水の温度のいずかれを検出するものとすればよい（請求項７）。太陽熱集熱器の表面温度は日射を受ける一方で内部の水と熱交換される結果、太陽熱集熱器で加熱されて蓄熱槽に戻される温水温度とほぼ同じ温度となる。また、太陽熱集熱器内部の循環流水の温度を検出する位置は太陽熱集熱器の内部位置でも、出口位置でもよい。これらの場合には、太陽熱集熱器と蓄熱槽との間の配管での放熱分を考慮に加えてもよい。さらに、蓄熱槽の頂部に戻される温度の検出位置は配管途中でも、蓄熱槽の頂部位置でもよい。
【００２０】
【発明の効果】
以上、説明したように、請求項１の太陽熱利用温水装置によれば、目標温度設定部によって検出日射量に対応する蓄熱温度よりも低い温度が集熱運転制御での目標温度としてまず設定されるため、上記蓄熱温度を最初から目標温度として設定する場合よりも短時間で蓄熱することができる上に、太陽熱を高効率で利用することができるようになる。加えて、低温側とはいえ上記目標温度の温水が蓄熱槽に早期に蓄熱されるため、給湯に供するために補助熱源機で加熱するにしても、その加熱のためのエネルギー消費の節減を図ることができる。
【００２１】
さらに、まずは低温側の目標温度の温水を早期に蓄熱した上で、より高温側の温水の蓄熱をも続行させることができ、蓄熱槽への蓄熱を段階的に行うことができるようになる。これにより、太陽熱の利用効率という観点において、より高温側までの蓄熱を天候の状況に応じて効率よく行うことができるようになる。なお、最初の目標温度として給湯用に要求される常用温度を設定することにより、給湯側に補助熱源機が介装されている場合には、その補助熱源機の加熱作動なしに蓄熱槽に蓄熱された温水をそのまま給湯させることができ、補助熱源機での加熱のためのエネルギー消費を不要とすることができる。
【００２２】
請求項２の太陽熱利用温水装置によれば、目標温度設定部によって検出日射量に対応する蓄熱温度よりも低い温度が集熱運転制御での目標温度としてまず設定されるため、上記蓄熱温度を最初から目標温度として設定する場合よりも短時間で蓄熱することができる上に、太陽熱を高効率で利用することができるようになる。加えて、低温側とはいえ上記目標温度の温水が蓄熱槽に早期に蓄熱されるため、給湯に供するために補助熱源機で加熱するにしても、その加熱のためのエネルギー消費の節減を図ることができる。さらに、その上に、目標温度設定部による目標温度の変更設定により、現在の季節情報を加味して日射量の季節変動特性に応じたより高温側の温水の蓄熱を効率よく続行させることができる。このため、目標温度を例えば冬期であっても画一的に６０℃に変更設定する場合に比して、実際の天候もしくは日射状況により対応させた蓄熱を行うことができる。
【００２３】
請求項３によれば、上記の請求項１又は請求項２の太陽熱利用温水装置において、集熱運転開始後、蓄熱槽の底部はまだ低温であっても、蓄熱槽の頂部に目標温度の温水を早期に確保することができ、目標温度の温水の早期利用を達成して補助熱源機での加熱のためのエネルギー消費を可及的に削減させることができる。
【００２４】
請求項４によれば、上記の請求項１〜請求項３のいずれかの太陽熱利用温水装置において、日射量が不十分であるときにおいても、まずは上記ＯＮ・ＯＦＦ運転制御を開始させることにより、目標温度よりは低温ではあっても太陽熱を少しでも蓄熱した上で、以後の目標温度に基づく蓄熱を実行させることができ、太陽熱の利用効率をより一層向上させることができる。
【００２５】
請求項５によれば、上記の請求項１〜請求項４のいずれかの太陽熱利用温水装置において、日射量検出手段による日射量検出を直接的に検出して把握することができ、集熱制御をより適切に実行させことができる。また、太陽電池を太陽熱利用温水装置の電源として用いる場合には、新たに日射量検出手段として特別なセンサを設置することなく併用させることができる。
【００２６】
請求項６によれば、上記の請求項１〜請求項４のいずれかの太陽熱利用温水装置において、日射量検出のための特別なセンサ等を設置することなく、太陽熱利用温水装置に対し他の用途のために通常設けられている検出手段を利用して演算により日射量を検出することができるようになる。
【００２７】
請求項７によれば、請求項１〜請求項６のいずれかの太陽熱利用温水装置において用いる第１温度検出手段として具体的態様を特定することができる。
【００２８】
【発明の実施の形態】
以下、本発明の実施形態を図面に基づいて説明する。
【００２９】
＜第１実施形態＞
図１は、本発明の第１実施形態に係る太陽熱利用温水装置を示し、２は蓄熱槽、３は太陽熱集熱器（コレクタ）である。
【００３０】
上記蓄熱槽２は例えばステンレス鋼板により形成された密閉容器である。この蓄熱槽２の底部には給水回路４の下流端と、集熱回路５の往き路５ａの上流端とがそれぞれ連通接続され、また、頂部には図示省略の補助熱源機としての給湯器１００（図８参照）を介して給湯させるための給湯回路６の上流端と、上記集熱回路５の戻り路５ｂの下流端とがそれぞれ連通接続されている。上記蓄熱槽２内は給水回路４からの水道水の給水により充満され、給湯回路６を通して給湯使用された分だけ給水回路４から補水されるようになっている。
【００３１】
上記集熱回路５の往き路５ａには、可変流量ポンプ（例えばＤＣポンプ）により構成された循環ポンプ７が介装されている。また、上記コレクタ３には、その表面温度を検出して第１温度検出手段として用いられる表面温度センサ９と、日射量検出手段の一部として用いられる太陽電池１２とが配設され、上記蓄熱槽２の底部には底部位置の水又は温水の温度（以下「底部温度」という）を検出する第２温度検出手段としての底部温度センサ１０が配設されている。
【００３２】
そして、上記循環ポンプ７が上記各センサ９，１０及び太陽電池１２の各出力に基づいて集熱運転制御手段を含むコントローラ１３により作動制御されて集熱運転が行われるようになっている。上記コントローラ１３はＭＰＵやメモリ等を備え予め搭載されたプログラムの実行や制御回路により各種制御が行われるようになっている。すなわち、上記コントローラ１３は集熱運転制御手段として図２に示すように比例集熱制御部１３１と、ＯＮ・ＯＦＦ運転制御部１３２と、比例集熱制御部１３１での目標温度を設定する目標温度設定部１３３と、上記比例集熱制御部１３１による比例集熱制御及び上記ＯＮ・ＯＦＦ運転制御部１３２による温度差ＯＮ・ＯＦＦ制御を切換える切換制御部１３４と、上記太陽電池１２からの出力に基づいて日射量を推定して検出する日射量検出手段の一部を構成する日射量推定部１３５とを備えている。
【００３３】
上記比例集熱制御部１３１は、上記循環ポンプ７の作動制御流量を上記蓄熱槽２内の底部から頂部までの間に温度差のある２以上の層が形成される低流量範囲として予め設定された成層流量範囲内に制限しつつ、上記表面温度センサ９の検出温度（表面温度）が上記目標温度設定部１３３により設定された目標温度になるように上記循環ポンプ７の回転数をフィードバック制御（ＦＢ制御）により変更調整して比例集熱制御を行うように構成されている。なお、上記循環ポンプ７はその回転数の変化により吐出流量が変化するタイプの可変流量ポンプであるため、作動制御流量での循環ポンプ７の作動制御を行うためにその回転数を制御している。回転数のＦＢ制御とは具体例を示すと、
制御回転数Ｎ＝Ｋ×（表面温度−目標温度）
となるようにする（Ｋ：比例定数）。これにより、上記表面温度は日射による集熱が循環により順次供給される水と熱交換されて上記目標温度で一定に維持されるようになり、蓄熱槽２には上記目標温度でほぼ一定の温水が戻される。
【００３４】
ここで、上記の成層流量範囲とは、蓄熱槽２内が戻り路５ｂからの戻り温水によりかき回されずに、より高温の温水が上側に層をなして貯留されて底部から頂部にわたり温度差のある層が形成される程度の低流量範囲のことであるが、その一方で集熱効率の低下を抑えてある程度の集熱効率を維持するために所定の流量範囲に設定されている。すなわち、図３にコレクタ３の１枚分についての集熱効率と循環流量との関係を示すように、集熱効率のＭＡＸ値（ほぼ５０％の集熱効率）に対しその５０〜９０％程度を達成し得る低効率範囲に対応する循環流量範囲の下限値をβ（Ｌ／ｍｉｎ）と設定している。そして、上記循環流量範囲の上限値、すなわち、コレクタ３での集熱効率を低下させずに温度差のある成層を形成可能な最大流量をα（Ｌ／ｍｉｎ）と設定している。つまり、成層流量範囲としてβ〜αを設定している。これはコレクタ３の１枚分についてであるため、コレクタ３が２枚以上ある場合には、その枚数分を上記β，αに乗じるようにすればよい。
【００３５】
上記目標温度設定部１３３は、目標温度として第１目標温度、第２目標温度というように順次高温側の温度に段階的に変更設定するようになっている。すなわち、まず低温側の温度を第１目標温度として設定し、次段階にそれよりも高温側の温度を第２目標温度として変更設定するようになっている。具体的には、日射量推定部１３５により得られた現在の日射量により加熱させ得る温水温度（蓄熱温度）よりも低い温度を第１目標温度として設定し、この第１目標温度での蓄熱が完了すれば、次段階の第２目標温度として第１目標温度と上記蓄熱温度との中間温度を設定し、この第２目標温度での蓄熱が完了すれば、最終目標温度である第３目標温度として上記蓄熱温度を設定するようになっている。この際、最終目標温度である上記蓄熱温度が例えば７５℃であれば、第１目標温度として補助熱源機１００（図８）での加熱なしに給湯し得る常用温度である例えば４０℃を設定し、第２目標温度として例えば６０℃を設定するようになっている。
【００３６】
上記ＯＮ・ＯＦＦ運転制御部１３２は、上記コレクタ表面温度センサ９及び底部温度センサ１０の両検出温度の差の如何に応じて上記循環ポンプ７を上記のαで固定してＯＮ・ＯＦＦの間欠作動させるようになっている。すなわち、「表面温度−底部温度」の温度差が例えば７℃以上あれば循環ポンプ７をＯＮ作動させ、上記温度差が４℃以下であれば循環ポンプ７をＯＦＦにする、という温度差ＯＮ−ＯＦＦ制御による間欠作動を行うようになっている。
【００３７】
上記切換制御部１３４は、集熱運転が開始されると、まずは上記ＯＮ・ＯＦＦ運転制御部１３２による温度差ＯＮ−ＯＦＦ制御を開始し、この制御実行中に日射量推定部１３５によって得られた現在の日射量が上記比例集熱制御部１３１での第１目標温度に基づく集熱を行うに十分な日射量であると判断されれば比例集熱制御部１３１による比例集熱制御に切換えるようになっている。そして、第１目標温度による比例集熱制御により蓄熱が完了すると、再び現在の日射量が次の第２目標温度に基づく集熱を行うに十分な日射量であると判断されれば、第２目標温度に基づく比例集熱制御を続行する一方、十分な日射量ではなければ上記ＯＮ・ＯＦＦ運転制御部１３２による温度差ＯＮ・ＯＦＦ制御に切換えるようになっている。
【００３８】
上記日射量推定部１３５は、太陽電池１２からの発電量に関する情報の出力を受け、その発電量と日射量とについて予め定めた関係から現在の日射量を推定して検出するようになっている。
【００３９】
以下、コントローラ１３による集熱運転制御について図４を参照しつつ説明する。使用者によるスイッチ操作又は内蔵時計や日射検知による運転指令の出力によって集熱運転スイッチがＯＮにされると集熱運転が開始される。集熱運転が開始されると、まずは上記ＯＮ・ＯＦＦ運転制御部１３２による温度差ＯＮ−ＯＦＦ制御を開始して日射量がたとえ低くても少しでも集熱して蓄熱する（Ｐ１）。そして、この制御実行中に日射量推定部１３５により現在の日射量を推定する（Ｐ２）。現在の日射量が上記目標温度設定部１３３により第１目標温度として設定される温度（常用温度４０℃）以上の温度まで加熱するに十分であると判断されるまで、つまり不十分である間は上記温度差ＯＮ・ＯＦＦ制御を継続させる（Ｐ２、Ｐ３でＮＯ、Ｐ４）。
【００４０】
現在の日射量が上記第１目標温度以上の温度まで加熱するに十分な日射量であると判断されると、コレクタ表面温度センサ９の表面温度が上記第１目標温度になるように比例集熱制御部１３１による比例集熱制御を開始する（Ｐ２、Ｐ３でＹＥＳ、Ｐ５）。つまり、現在の日射量が７５℃まで加熱し得る程度であっても、第１目標温度としては敢えて４０℃という低温側の温度を設定し、この第１目標温度になるように比例集熱制御を行う。この比例集熱制御においては上記の検出表面温度が第１目標温度になるように循環ポンプ７の回転数をＦＢ制御することにより作動制御流量（循環流量）を変更調整する。この際、ＦＢ制御値が前述のα（Ｌ／ｍｉｎ）を超える場合にはＦＢ制御値をα（Ｌ／ｍｉｎ）に強制的に設定して成層蓄熱を維持する一方、急に曇る等によりＦＢ制御値がβ（Ｌ／ｍｉｎ）未満という極めて低流量になってしまう場合には、つまり、循環流量をβ（Ｌ／ｍｉｎ）未満にＦＢ制御しないと集熱し得ない程度の日射量に急変した場合には、循環ポンプ７を一時的にＯＦＦ（比例集熱制御を停止）にして日射量の回復を待つ。以上により、循環流量の変更調整をβ〜αの成層流量範囲内に維持した状態で、蓄熱槽２の底部温度が第１目標温度である常用温度（４０℃）に到達するまで継続させる（Ｐ６でＮＯ、Ｐ５）。
【００４１】
そして、この比例集熱制御の実行によって蓄熱槽２内の全てが第１目標温度の温水で満たされれば、つまり、頂部側から徐々に蓄積されるため底部温度センサ１０により検出される底部温度が上記第１目標温度に到達すれば、再びそのときの日射量の推定を行う（Ｐ６でＹＥＳ、Ｐ７）。この日射量が目標温度設定部１３３により次に設定される第２目標温度（例えば６０℃）以上の温度まで加熱し得るに十分な程度なければ、つまり日射量が不十分であればＯＮ・ＯＦＦ運転制御部１３２による温度差ＯＮ・ＯＦＦ制御に切換え、日射量が上記の十分な程度になるまで温度差ＯＮ・ＯＦＦ制御を持続させる（Ｐ８でＮＯ、Ｐ９）。逆に、第１目標温度での温水の蓄熱が完了した段階でも日射量が上記の十分な程度あれば、それまでの比例集熱制御の目標温度を上記第２目標温度に変更した上で、比例集熱制御を続行する（Ｐ８でＹＥＳ、Ｐ１０）。
【００４２】
そして、図示を省略しているが、蓄熱槽２の底部温度が上記第２目標温度に到達して蓄熱槽２内の全てに第２目標温度の蓄熱が完了すれば、上記のＰ７〜Ｐ１０の処理と同様に目標温度を最終蓄熱温度である第３目標温度（７５℃）に変更して比例集熱制御を行い、第３目標温度の蓄熱を行う。
【００４３】
以上によれば、日射量が最終蓄熱温度（７５℃）まで加熱可能な程度あったとしても、まずは第１目標温度として４０℃での蓄熱を行い、次に第２目標温度としての６０℃での蓄熱を行い、最後に第３目標温度としての７５℃での蓄熱を行うという段階的な蓄熱を行うことにより、最初から最終蓄熱温度の７５℃を目標温度にして循環ポンプ７の循環量を変更調整する比例制御を行う場合に比べ、大幅に短時間での蓄熱が可能となる。その際に、上記第１〜第３目標温度を目標温度とする本実施形態の比例集熱制御では循環ポンプ７の作動制御流量を成層流量範囲に制限しているため、蓄熱槽２には成層蓄熱（成層状態での蓄熱）が行われ、蓄熱槽２の頂部に対し極めて早期にそのときの目標温度の温水を確保することができる。また、比例集熱制御が日射量が不十分で行わないときにも、温度差ＯＮ・ＯＦＦ制御を行うようにしているため、天候の状況に応じて太陽熱の利用効率を十分に高めることができる。
【００４４】
＜第２実施形態＞
図５は、本発明の第２実施形態に係る太陽熱利用温水装置を示す。この第２実施形態は、第１実施形態の太陽電池１２を省略して第１実施形態とは異なる日射量検出手段を採用する一方、第１実施形態とは異なる構成の集熱運転制御手段を含むコントローラ１４を備えたものである。そして、それに伴い、第１実施形態には設けていない、循環流量を検出する流量検出手段としての流量センサ８と、集熱回路５の戻り路５ｂの蓄熱槽２近傍位置に配設されコレクタ３から蓄熱槽２に戻される加熱後の温水温度（以下「戻り温度」という）を検出する第１温度検出手段としての戻り温度センサ１１とを追加したものである。なお、上記第２実施形態のその他の構成要素は第１実施形態のものと同様構成であるため、同一構成要素には同一符号を付してその詳細な説明は省略する。
【００４５】
上記コントローラ１４は、第１実施形態と同様にＭＰＵやメモリ等を備え予め搭載されたプログラムの実行や制御回路により各種制御が行われるようになっている。すなわち、上記コントローラ１４は、集熱運転制御手段として図６に示すように比例集熱制御部１３１と、ＯＮ・ＯＦＦ運転制御部１３２と、比例集熱制御部１３１での目標温度を設定する目標温度設定部１４１と、現在の季節情報を計時しこの季節情報に応じて予め定められた第２目標温度を上記目標温度設定部１４１に対し出力する季節情報出力部としてのカレンダ部１４２と、上記比例集熱制御部１３１による比例集熱制御及び上記ＯＮ・ＯＦＦ運転制御部１３２による温度差ＯＮ・ＯＦＦ制御を切換える切換制御部１３４と、各種センサ８，１０，１１からの出力に基づいて日射量を演算により推定して検出する日射量検出手段の一部を構成する日射量演算部１４３とを備えている。
【００４６】
上記目標温度設定部１４１は、第１実施形態の目標温度設定部１３３と同様に目標温度として第１目標温度、第２目標温度というように順次高温側の温度に段階的に変更設定するように構成されたものであるが、第２目標温度として上記カレンダ部１４２から取得した温度値を設定するようになっている点で第１実施形態の目標温度設定部１３３と異なる。具体的には、日射量推定部１３５により得られた現在の日射量により加熱させ得る温水温度（蓄熱温度）よりも低い温度を第１目標温度として設定し、この第１目標温度での蓄熱が完了すれば、次段階の第２目標温度として第１目標温度と上記蓄熱温度との中間温度であって上記カレンダ部１４２から出力される温度を設定し、この第２目標温度での蓄熱が完了すれば、最終目標温度である第３目標温度として上記蓄熱温度を設定するようになっている。この際、最終目標温度である上記蓄熱温度が例えば７５℃であれば、第１目標温度としては第１実施形態と同様に補助熱源機１００（図８）での加熱なしに給湯し得る常用温度である例えば４０℃を設定し、第２目標温度として後述の季節変動特性を加味した温度値を設定するようになっている。
【００４７】
上記カレンダ部１４２は、計時により現在が少なくとも何月かを季節情報として把握し、この季節情報と予め関係付けられた温度値を上記目標温度設定部１４１に出力するようになっている。例えば現在が１２月〜２月の冬期であれば５５℃を、６月〜８月の夏期であれば６５℃を、３月〜５月の春期や９月〜１１月の秋期であれば６０℃をそれぞれ出力するようになっている。
【００４８】
上記日射量演算部１４３は、流量センサ８により検出される循環流量値と、戻り温度センサ１１により検出される戻り温度から底部温度センサ１０により検出される底部温度を差し引いた温度差とに基づいて、単位時間当たりの集熱量を演算により求め、この集熱量と日射量との相関関係より現在の日射量を推定して得るようになっている。
【００４９】
上記コントローラ１４による集熱運転制御は、上記の第２目標温度の設定が相違するのみで、その殆どが第１実施形態のコントローラ１３と同様の内容を有している。すなわち、図４に示すように、集熱運転が開始されると、まずは上記ＯＮ・ＯＦＦ運転制御部１３２による温度差ＯＮ−ＯＦＦ制御を開始し（Ｐ１）、その制御実行中に日射量演算部１４３により現在の日射量を推定する（Ｐ２）。現在の日射量が上記目標温度設定部１４１により第１目標温度として設定される温度（常用温度４０℃）以上の温度まで加熱するに十分であると判断されるまで、上記温度差ＯＮ・ＯＦＦ制御を継続させる一方（Ｐ２、Ｐ３でＮＯ、Ｐ４）、現在の日射量が上記第１目標温度以上の温度まで加熱するに十分な日射量であると判断されると、コレクタ表面温度センサ９の表面温度が上記第１目標温度になるように比例集熱制御部１３１による比例集熱制御を開始する（Ｐ２、Ｐ３でＹＥＳ、Ｐ５）。この比例集熱制御により、循環流量の変更調整を第１実施形態で説明したβ〜αの成層流量範囲内に維持した状態で、蓄熱槽２の底部温度が第１目標温度である常用温度（４０℃）に到達するまで継続させる（Ｐ６でＮＯ、Ｐ５）。
【００５０】
そして、この比例集熱制御の実行によって蓄熱槽２内の全てが第１目標温度の温水で満たされれば、つまり、頂部側から徐々に蓄積されるため底部温度センサ１０により検出される底部温度が上記第１目標温度に到達すれば、再びそのときの日射量の推定を行うと共に（Ｐ６でＹＥＳ、Ｐ７）、カレンダ部１４２から現在の季節変動特性を加味した第２目標温度を取得する（Ｐ１１）。この日射量が上記第２目標温度（例えば４月であれば６０℃）以上の温度まで加熱し得るに十分な程度なければ、つまり日射量が不十分であればＯＮ・ＯＦＦ運転制御部１３２による温度差ＯＮ・ＯＦＦ制御に切換え、日射量が上記の十分な程度になるまで温度差ＯＮ・ＯＦＦ制御を持続させる（Ｐ８でＮＯ、Ｐ９）。逆に、日射量が上記の十分な程度あれば、それまでの比例集熱制御の目標温度を上記第２目標温度に変更した上で、比例集熱制御を続行する（Ｐ８でＹＥＳ、Ｐ１０）。
【００５１】
そして、蓄熱槽２の底部温度が上記第２目標温度に到達して蓄熱槽２内の全てに第２目標温度の蓄熱が完了すれば、上記のＰ７〜Ｐ１０の処理と同様に目標温度を最終蓄熱温度である第３目標温度（７５℃）に変更して比例集熱制御を行い、第３目標温度の蓄熱を行う。
【００５２】
以上によれば、第１実施形態と同様の作用・効果を得ることができる上に、特に段階的蓄熱の中間段階において季節に基づく太陽熱等の変動特性を加味した第２目標温度を用いて蓄熱を行うことができる。このため、まずは低温側の第１目標温度の温水を早期に蓄熱した上で、太陽熱の季節変動特性に応じたより高温側の第２目標温度の温水の蓄熱を効率よく続行させることができる。これにより、段階的蓄熱を、第２目標温度を季節に関わりなく画一的に設定する場合と比べ、効率よく行うことができるようになる。
【００５３】
＜他の実施形態＞
なお、本発明は上記第１及び第２実施形態に限定されるものではなく、その他種々の実施形態を包含するものである。すなわち、上記第１実施形態での太陽電池１２を用いた日射量検出手段を第２実施形態に適用してもよく、あるいは、逆に第２実施形態での日射量演算部１４３を用いた日射量検出手段を第１実施形態に適用してもよい。
【００５４】
さらに、第１又は第２実施形態に対し、図７に示すような熱電対を利用した日射量検出手段１５を適用するようにしてもよい。図７の日射量検出手段１５は、太陽の日射を受ける受熱領域１５１を４等分にし、２つの領域を吸熱のよい黒色に着色し、他の２つの領域を熱を反射し易い白色に着色し、黒色領域１５２，１５２にそれぞれ熱電対１５３を、白色領域１５４，１５４にもそれぞれ熱電対１５５を設置したものである。そして、１組の熱電対１５３，１５３と、他の１組の熱電対１５５，１５５との電位差を検出し、このような電位差と日射量との相関関係から現在の日射量を推定するようにしたものである。なお、上記受熱領域１５１の上側は風よけのために透明な風防が被せられている。
【図面の簡単な説明】
【図１】本発明の第１実施形態の太陽熱利用温水装置を示す模式図である。
【図２】第１実施形態のコントローラの内容を示すブロック図である。
【図３】集熱効率と循環流量との関係を示すグラフである。
【図４】第１実施形態及び第２実施形態による集熱制御を示すフローチャートである。
【図５】第２実施形態の太陽熱利用温水装置を示す模式図である。
【図６】第２実施形態のコントローラの内容を示すブロック図である。
【図７】日射量検出手段の他の形態を示す平面図である。
【図８】太陽熱利用温水装置と補助熱源機との関係を示す模式図である。
【符号の説明】
２蓄熱槽
３コレクタ（太陽熱集熱器）
７循環ポンプ
８流量センサ（流量検出手段）
９コレクタ表面温度センサ（第１温度検出手段）
１０底部温度センサ（第２温度検出手段）
１１戻り温度センサ（第１温度検出手段）
１２太陽電池（日射量検出手段）
１３，１４コントローラ（集熱運転制御手段）
１５日射量検出手段
１３１比例集熱制御部
１３２ＯＮ・ＯＦＦ運転制御部
１３３，１４１目標温度設定部
１３５日射量推定部（日射量検出手段）
１４２カレンダ部（季節情報出力部）
１４３日射量演算部（日射量検出手段）[0001]
BACKGROUND OF THE INVENTION
The present invention forcibly circulates water in a heat storage tank with a solar heat collector (collector) by the operation of a circulation pump to store solar heat as hot water, and stores this hot water as an auxiliary heat source such as a water heater. The present invention relates to a solar-powered hot water device used for feeding to a hot water tap through a machine and using it for hot water supply.
[0002]
[Prior art]
Conventionally, the following proportional operation control has been generally performed as a heat collection operation control by this type of solar thermal water heater. That is, the circulating pump 70 shown in FIG. 8 is continuously operated so that the temperature of the collector 3 (surface temperature) or the temperature of the hot water at the outlet of the collector 3 becomes a set temperature (for example, 60 to 75 ° C.). The circulation flow rate is changed and controlled. In this case, a variable flow rate pump is used as the circulation pump 70, and the discharge flow rate, that is, the circulation flow rate is changed and controlled by changing and controlling the rotation speed, for example. The surface temperature of the collector 3 is heated by receiving solar radiation, while heat is taken away by heat exchange with the inner circulating water, so that the temperature of the hot water raised by the solar heat and returned to the heat storage tank is almost the same. Will represent.
[0003]
Moreover, although the hot water stored in the thermal storage tank 2 by the solar-heated hot water apparatus is normally taken out from the thermal storage tank 2 and used for hot water supply, the hot water in the thermal storage tank 2 is required as hot water supply at that time. In some cases, the temperature may be lower. Therefore, generally, as shown in FIG. 8, an auxiliary heat source device (for example, a hot water heater) 100 is interposed between the heat storage tank 2 and the hot water tap, and the hot water taken out from the heat storage tank 2 is used as the auxiliary heat source apparatus. After heating at 100, hot water is supplied to the hot water tap at the downstream end.
[Problems to be solved by the invention]
However, since the amount of solar radiation varies depending on the weather conditions, according to the heat collection operation control described above, if the amount of solar radiation is small, it takes a long time to store hot water at the set temperature in the heat storage tank 2. In addition, the heat collection efficiency, that is, the utilization efficiency of solar heat is also reduced. In addition, if hot water supply is used until then, it is necessary to add heating by the auxiliary heat source unit 100, and there is a disadvantage that more energy (fossil fuel energy or electric energy) is consumed for the heating. .
[0004]
That is, even when the sun rises, if the amount of solar radiation is such that the temperature of the collector 3 is raised only to the limit of the set temperature or only raised around the set temperature, the temperature is raised to the set temperature. The circulation flow rate is controlled to be extremely small, the heat collection efficiency is extremely lowered, and it takes a long time to store heat. Such inconvenience is likely to occur especially in the morning from sunrise.
[0005]
The present invention has been made in view of such circumstances, and an object of the present invention is to store hot water at a temperature required for hot water supply in a shorter time and to store the heat storage in a weather situation. Accordingly, an object is to provide a solar water heater that can be efficiently performed.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, forced circulation is performed so that the water at the bottom of the heat storage tank is supplied to the solar heat collector by the operation of the circulation pump and the hot water heated by the solar heat collector is returned to the top of the heat storage tank. The following specific items were provided for a solar water heating hot water device configured to perform a heat collecting operation and store solar heat as hot water in the heat storage tank.
[0007]
That is, in the invention according to claim 1, Received by the above solar collector An amount of solar radiation detecting means for detecting the amount of solar radiation, a first temperature detecting means for detecting the temperature of hot water to be returned from the solar heat collector to the top of the heat storage tank, and a temperature detected by the first temperature detecting means Heat collection operation control means for performing heat collection operation control by operating the circulation pump so as to reach the target temperature is provided. And as the said heat collection operation control means, it shall have the target temperature setting part which sets a target temperature based on the amount of solar radiation detected from the said solar radiation amount detection means, and as this target temperature setting part, with the said detected solar radiation amount The target temperature is a temperature lower than the heat storage temperature determined by the relationship. First set, then change the target temperature to the above heat storage temperature or to the high temperature side temperature in the range up to the above heat storage temperature. The configuration is as follows.
[0008]
In addition, as the above “heat collection operation control”, proportional operation control in which the detected temperature becomes the target temperature by continuously operating the circulation pump and changing and adjusting the circulation flow rate by the circulation pump may be performed. The ON / OFF operation control may be performed so that the detected temperature becomes the target temperature by intermittently operating the circulation pump at a constant flow rate. The following claims 2 It is the same in the above.
[0009]
According to the first aspect, the target temperature setting unit lowers the heat storage temperature corresponding to the detected solar radiation amount, that is, the current solar radiation amount after heating that can be heated at a circulation flow rate with normal heat collection efficiency. Since a temperature lower than the hot water temperature is first set as the target temperature in the heat collection operation control, if the heat collection operation control (circulation pump operation control) is performed at such a target temperature, the above-mentioned heat storage temperature is set from the beginning. In addition to being able to store heat in a shorter time than when it is set as temperature, it is also possible to use solar heat with high efficiency. For example, in the case of executing the above proportional operation control, for example, the circulation flow rate is larger when the target temperature is initially set to 40 ° C. than when the target temperature is initially set to 75 ° C., or the above-described ON / OFF operation control is performed. Since the ON operation time of the circulation pump becomes longer when the operation is performed, the hot water at the target temperature can be stored in the heat storage tank in a short time, and the utilization efficiency of solar heat is also increased. In addition, since the hot water of the target temperature on the low temperature side is stored in the heat storage tank at an early stage, even if it is heated by the auxiliary heat source unit to supply hot water, energy consumption for the heating can be reduced.
[0011]
As above, first If the heat collection operation control is performed based on the target temperature set at a temperature lower than the heat storage temperature determined according to the detected solar radiation amount, and the hot water at the target temperature is stored in the heat storage tank, then the higher temperature side Heat collection operation control based on the target temperature changed and set to the temperature is performed, and hot water having a higher temperature is stored in the heat storage tank, so that heat storage in the heat storage tank is performed in stages. For this reason, Above In addition to obtaining the action, it is possible to continue the heat storage of the hot water on the higher temperature side. Thereby, in terms of solar heat utilization efficiency, heat storage up to a higher temperature side can be efficiently performed according to the weather conditions.
[0012]
Here, the target temperature change setting by the target temperature setting unit may be performed by setting a temperature lower than the heat storage temperature as the first target temperature and then changing the heat storage temperature as the second target temperature, or The intermediate temperature between the first target temperature and the heat storage temperature may be changed and set as the second target temperature. In the latter case, the heat storage temperature may be further changed and set as the third target temperature, or the intermediate temperature on the higher temperature side may be changed and set stepwise as the third or fourth target temperature. The heat storage temperature may be changed and set as the target temperature. For such stepwise change settings, the following claims 2 In the same manner, it can be adopted. Moreover, as said 1st target temperature, although you may determine in relation with the temperature of the thermal storage tank bottom part supplied to a solar-heat collector from a thermal storage tank, and the amount of detected solar radiation, it is the normal temperature requested | required for hot water supply It is preferable to set (for example, 40 ° C.). In this way, when an auxiliary heat source device is interposed on the hot water supply side, it becomes possible to supply hot water stored in the heat storage tank as it is without heating operation of the auxiliary heat source device, and the auxiliary heat source device It becomes possible to omit the energy consumption for heating in the oven.
[0013]
Claim 2 In the invention which concerns on this, the solar radiation amount detection means which detects the solar radiation amount which the said solar thermal combustor receives, and the 1st temperature detection means which detects the temperature of the warm water which will be returned to the top part of a thermal storage tank from the said solar thermal collector The heat collection operation control means for performing the heat collection operation control by operating the circulation pump so that the temperature detected by the first temperature detection means becomes the target temperature. As the heat collection operation control means in this case, the target is based on the seasonal information output unit that outputs information on the current season by timing, and the detected solar radiation amount from the solar radiation amount detection means or the seasonal information from the seasonal information output unit. It shall have a target temperature setting part which sets temperature. Then, as the target temperature setting unit, a temperature lower than the heat storage temperature determined in relation to the detected amount of solar radiation is first set as a target temperature, and thereafter, the target temperature is set according to the season information from the season information output unit. It is set as the structure changed and set to the predetermined high temperature side temperature.
[0014]
This claim 2 Accordingly, all of the effects of the second aspect can be obtained, and the target temperature change setting by the target temperature setting unit can be changed in consideration of the current season information. For this reason, first, the hot water of the target temperature on the low temperature side is quickly stored, and then the heat storage of the hot water on the higher temperature side according to the seasonal variation characteristics of the solar radiation amount can be continued efficiently. The above "seasonal information" is January, February, March ... like Even information by month may be information on the four seasons such as spring, summer, autumn, and winter. And if it is monthly, the second target temperature is changed and set, for example, 55 ° C. from December to February, 65 ° C. from June to August, and 60 ° C. in other months. For the four seasons, the second target temperature may be changed to 55 ° C. in the winter, 65 ° C. in the summer, and 60 ° C. in the spring or autumn. In this way, for example, even in the winter season, heat storage corresponding to actual weather conditions or solar radiation conditions is possible as compared with the case where 60 ° C. is uniformly set as the second target temperature.
[0015]
Claim 1 above Or claim 2 In the solar thermal water heater, when performing operation control for continuous operation while changing and adjusting the circulation flow rate of the circulation pump, the following operation may be performed. That is, the circulation pump is constituted by a variable flow rate pump, and the heat collection operation control means has an operation control flow rate by the circulation pump of two or more layers having a temperature difference from the bottom to the top in the heat storage tank. It may be configured to change and adjust by proportional control so that the detected temperature becomes the target temperature while limiting within a stratified flow rate range set in advance as a low flow rate range in which is formed. 3 ). By limiting the operation control flow rate of the circulation pump within the stratified flow rate range, two or more layers having a temperature difference from the bottom to the top are stratified in the heat storage tank. That is, even if the hot water heated by the solar heat collector is returned to the heat storage tank, the heated water is sequentially accumulated from the top without being stirred in the heat storage tank because of the low flow rate. For this reason, even after the start of the heat collecting operation, even if the bottom of the heat storage tank is still at a low temperature, hot water at the target temperature is secured early on the top of the heat storage tank, and early use of the hot water at the target temperature is possible.
[0016]
Claims 1 to above 3 In any one of the solar-heated hot water apparatuses, the apparatus further comprises second temperature detecting means for detecting the temperature of the water at the bottom of the heat storage tank or the hot water, and as the heat collecting operation control means, First, temperature difference ON / OFF operation control is performed to intermittently operate the circulating pump at a predetermined flow rate according to the difference in temperature detected by the first temperature detection means and the second temperature detection means, and thereafter Further, a configuration for starting the operation control of the circulation pump based on the target temperature may be added. 4 ). In this case, even when the amount of solar radiation is insufficient, by starting the temperature difference ON / OFF operation control, it is possible to store solar heat even if it is lower than the target temperature. Become.
[0017]
Claims 1 to above 4 As the solar radiation amount detecting means used in any one of the solar thermal water heaters, various devices can be adopted. For example, the solar radiation amount detecting means may include a solar cell disposed on the surface of the solar heat collector, and may be configured to estimate and detect the solar radiation amount based on the power generation amount of the solar cell. 5 ). In this case, it becomes possible to directly detect and grasp the amount of solar radiation as compared with the configuration described later, and heat collection control is executed more appropriately. Setsu The
[0018]
Alternatively, the flow rate detection means for detecting the circulation flow rate by the operation of the circulation pump and the second temperature detection means for detecting the temperature of the water or hot water at the bottom of the heat storage tank are further provided. A configuration for estimating and detecting the amount of solar radiation based on the amount of heat collected by multiplying the detected flow rate by the detecting means and the temperature difference between both detected temperatures by the first and second temperature detecting means. You may make it adopt (claim) 6 ). In this case, without installing a special sensor for detecting the amount of solar radiation, the amount of solar radiation is detected by calculation using the detection means normally provided for other uses for the solar water heating system. Will be able to.
[0019]
In addition, said claim 1-claim 6 As the first temperature detection means in any one of the solar thermal water heaters, the surface temperature of the solar heat collector during forced circulation or the temperature of the circulating water in the solar heat collector, or the solar heat collector is returned to the top of the heat storage tank. The temperature of the hot water to be detected should be detected. 7 ). The surface temperature of the solar heat collector is exposed to solar radiation and heat exchanged with the internal water. As a result, the surface temperature of the solar heat collector is almost the same as the hot water temperature heated by the solar heat collector and returned to the heat storage tank. Moreover, the position which detects the temperature of the circulating flowing water inside a solar-heat collector may be an internal position of a solar-heat collector, or an exit position. In these cases, the heat radiation in the pipe between the solar heat collector and the heat storage tank may be taken into consideration. Furthermore, the detection position of the temperature returned to the top of the heat storage tank may be in the middle of the piping or the top position of the heat storage tank.
[0020]
【The invention's effect】
As described above, according to the solar heat water heater of claim 1, a temperature lower than the heat storage temperature corresponding to the detected solar radiation amount is first set as the target temperature in the heat collection operation control by the target temperature setting unit. Therefore, heat can be stored in a shorter time than when the heat storage temperature is set as the target temperature from the beginning, and solar heat can be used with high efficiency. In addition, because the hot water at the target temperature is stored in the heat storage tank at an early stage although it is on the low temperature side, even if it is heated with an auxiliary heat source device to supply hot water, energy consumption for the heating is reduced. be able to.
[0021]
The In addition, the hot water of the target temperature on the low temperature side can be stored at an early stage, and then the heat storage of the hot water on the higher temperature side can be continued, and heat storage in the heat storage tank can be performed in stages. . Thereby, in terms of solar heat utilization efficiency, heat storage up to a higher temperature side can be efficiently performed according to the weather conditions. In addition, by setting the normal temperature required for hot water supply as the first target temperature, if an auxiliary heat source unit is installed on the hot water supply side, the heat storage tank can store heat without heating the auxiliary heat source unit. The heated hot water can be supplied as it is, and energy consumption for heating by the auxiliary heat source machine can be eliminated.
[0022]
Claim 2 According to the solar thermal water heater Since the target temperature setting unit first sets a temperature lower than the heat storage temperature corresponding to the detected solar radiation amount as the target temperature in the heat collection operation control, the heat storage temperature is set in a shorter time than when the heat storage temperature is set as the target temperature from the beginning. In addition to being able to store heat, solar heat can be used with high efficiency. In addition, because the hot water at the target temperature is stored in the heat storage tank at an early stage although it is on the low temperature side, even if it is heated with an auxiliary heat source device to supply hot water, energy consumption for the heating is reduced. be able to. On top of that By setting the target temperature to be changed by the target temperature setting unit, it is possible to efficiently continue the heat storage of the hot water on the higher temperature side according to the seasonal variation characteristics of the solar radiation amount in consideration of the current seasonal information. For this reason, compared with the case where the target temperature is changed and set to 60 ° C. even in the winter, for example, heat storage corresponding to actual weather or solar radiation conditions can be performed.
[0023]
Claim 3 According to claim 1 above Or claim 2 In the solar thermal water heater, after the start of the heat collection operation, even if the bottom of the heat storage tank is still low temperature, hot water at the target temperature can be secured at the top of the heat storage tank at an early stage, and the target water can be used early. And the energy consumption for heating in the auxiliary heat source machine can be reduced as much as possible.
[0024]
Claim 4 According to claim 1 to claim 1 above 3 In any of the solar thermal water heaters, even when the amount of solar radiation is insufficient, the above ON / OFF operation control is started first to store solar heat even if it is lower than the target temperature. Thus, heat storage based on the target temperature thereafter can be executed, and the utilization efficiency of solar heat can be further improved.
[0025]
Claim 5 According to claim 1 to claim 1 above 4 In any one of the solar thermal water heaters, the solar radiation amount detection by the solar radiation amount detecting means can be directly detected and grasped, and the heat collection control can be executed more appropriately. Moreover, when using a solar cell as a power supply of a solar-heat utilization hot water apparatus, it can be used together without installing a special sensor newly as a solar radiation amount detection means.
[0026]
Claim 6 According to claim 1 to claim 1 above 4 In any of the solar thermal water heaters, without using a special sensor for detecting the amount of solar radiation, the solar thermal water heater is operated using the detection means normally provided for other uses. It becomes possible to detect the amount of solar radiation.
[0027]
Claim 7 According to claim 1 to claim 6 A specific aspect can be specified as the first temperature detection means used in any one of the solar thermal water heaters.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0029]
<First Embodiment>
FIG. 1 illustrates a solar water heater according to the first embodiment of the present invention, 2 is a heat storage tank, and 3 is a solar heat collector (collector).
[0030]
The heat storage tank 2 is a sealed container formed of, for example, a stainless steel plate. The bottom of the heat storage tank 2 is connected to the downstream end of the water supply circuit 4 and the upstream end of the outgoing path 5a of the heat collecting circuit 5, and the water heater 100 as an auxiliary heat source machine (not shown) is connected to the top. The upstream end of the hot water supply circuit 6 for supplying hot water via (see FIG. 8) and the downstream end of the return path 5b of the heat collecting circuit 5 are connected in communication. The inside of the heat storage tank 2 is filled with tap water supplied from the water supply circuit 4, and water is supplied from the water supply circuit 4 by the amount of hot water used through the hot water supply circuit 6.
[0031]
A circulation pump 7 composed of a variable flow rate pump (for example, a DC pump) is interposed in the outgoing path 5 a of the heat collecting circuit 5. Further, the collector 3 is provided with a surface temperature sensor 9 that detects the surface temperature and is used as first temperature detecting means, and a solar cell 12 that is used as part of the solar radiation amount detecting means, and the heat storage A bottom temperature sensor 10 as second temperature detecting means for detecting the temperature of the water or hot water at the bottom position (hereinafter referred to as “bottom temperature”) is disposed at the bottom of the tank 2.
[0032]
The circulation pump 7 is controlled by the controller 13 including the heat collection operation control means based on the outputs of the sensors 9 and 10 and the solar cell 12 to perform the heat collection operation. The controller 13 includes an MPU, a memory, and the like, and various controls are performed by execution of a preinstalled program and a control circuit. That is, the controller 13 serves as a heat collecting operation control means, as shown in FIG. 2, a target temperature for setting a target temperature in the proportional heat collecting control unit 131, the ON / OFF operation control unit 132, and the proportional heat collecting control unit 131. Based on an output from the solar cell 12, a setting control unit 133, a switching control unit 134 that switches proportional heat collection control by the proportional heat collection control unit 131 and temperature difference ON / OFF control by the ON / OFF operation control unit 132. And a solar radiation amount estimating unit 135 constituting a part of the solar radiation amount detecting means for estimating and detecting the solar radiation amount.
[0033]
The proportional heat collection control unit 131 sets the operation control flow rate of the circulation pump 7 in advance as a low flow rate range in which two or more layers having a temperature difference are formed from the bottom to the top in the heat storage tank 2. The rotational speed of the circulation pump 7 is feedback-controlled so that the detected temperature (surface temperature) of the surface temperature sensor 9 becomes the target temperature set by the target temperature setting unit 133 while limiting within the stratified flow rate range ( It is configured to perform proportional heat collection control by changing and adjusting by (FB control). Since the circulation pump 7 is a variable flow pump whose discharge flow rate changes according to the change in the rotation speed, the rotation speed is controlled in order to control the operation of the circulation pump 7 at the operation control flow rate. . A specific example of the FB control of the rotational speed is as follows:
Control speed N = K x (Surface temperature-Target temperature)
(K: proportionality constant). As a result, the surface temperature is kept constant at the target temperature by heat exchange with the water sequentially supplied by circulation of heat collected by solar radiation, and the heat storage tank 2 has hot water that is substantially constant at the target temperature. Is returned.
[0034]
Here, the above stratified flow rate range means that the inside of the heat storage tank 2 is not stirred by the return warm water from the return path 5b, and hot water having a higher temperature is stored in a layer on the upper side and has a temperature difference from the bottom to the top. This is a low flow rate range in which a layer is formed, but on the other hand, it is set to a predetermined flow rate range in order to suppress a decrease in heat collection efficiency and maintain a certain level of heat collection efficiency. That is, as shown in FIG. 3 showing the relationship between the heat collection efficiency and the circulation flow rate for one collector 3, about 50 to 90% of the MAX value of the heat collection efficiency (the heat collection efficiency of about 50%) is achieved. The lower limit value of the circulating flow rate range corresponding to the low efficiency range to be obtained is set to β (L / min). The upper limit value of the circulation flow rate range, that is, the maximum flow rate at which a stratification with a temperature difference can be formed without reducing the heat collection efficiency in the collector 3 is set to α (L / min). That is, β to α are set as the stratification flow rate range. Since this is for one collector 3, when there are two or more collectors 3, it is only necessary to multiply the number β by the number of collectors 3.
[0035]
The target temperature setting unit 133 sequentially changes and sets the target temperature to the higher temperature side, such as the first target temperature and the second target temperature. That is, first, the temperature on the low temperature side is set as the first target temperature, and the temperature on the higher temperature side is changed and set as the second target temperature in the next stage. Specifically, a temperature lower than the hot water temperature (heat storage temperature) that can be heated by the current solar radiation amount obtained by the solar radiation amount estimation unit 135 is set as the first target temperature, and the heat storage at the first target temperature is If completed, an intermediate temperature between the first target temperature and the heat storage temperature is set as the second target temperature of the next stage, and when the heat storage at the second target temperature is completed, the third target temperature which is the final target temperature is set. The heat storage temperature is set as follows. At this time, if the heat storage temperature that is the final target temperature is, for example, 75 ° C., the first target temperature is set to, for example, 40 ° C., which is a normal temperature at which hot water can be supplied without heating in the auxiliary heat source apparatus 100 (FIG. 8). For example, 60 ° C. is set as the second target temperature.
[0036]
The ON / OFF operation control unit 132 fixes the circulating pump 7 at the α according to the difference between the detected temperatures of the collector surface temperature sensor 9 and the bottom temperature sensor 10 and performs intermittent ON / OFF operation. It is supposed to let you. That is, if the temperature difference of “surface temperature−bottom temperature” is 7 ° C. or more, for example, the circulation pump 7 is turned on, and if the temperature difference is 4 ° C. or less, the circulation pump 7 is turned off. Intermittent operation by OFF control is performed.
[0037]
When the heat collection operation is started, the switching control unit 134 first starts the temperature difference ON-OFF control by the ON / OFF operation control unit 132, and is obtained by the solar radiation amount estimation unit 135 during the execution of this control. If it is determined that the current amount of solar radiation is sufficient for performing heat collection based on the first target temperature in the proportional heat collection control unit 131, the proportional heat collection control unit 131 switches to proportional heat collection control. It has become. And if heat storage is completed by proportional heat collection control by the 1st target temperature, if it is judged that the present amount of solar radiation is the amount of solar radiation enough to perform heat collection based on the next 2nd target temperature again, the 2nd While the proportional heat collection control based on the target temperature is continued, if the amount of solar radiation is not sufficient, the temperature difference ON / OFF control by the ON / OFF operation control unit 132 is switched.
[0038]
The said solar radiation amount estimation part 135 receives the output of the information regarding the electric power generation amount from the solar cell 12, and estimates and detects the present solar radiation amount from the predetermined relationship about the electric power generation amount and the solar radiation amount. .
[0039]
Hereinafter, the heat collection operation control by the controller 13 will be described with reference to FIG. When the heat collection operation switch is turned on by the switch operation by the user or the output of the operation command by the built-in clock or solar radiation detection, the heat collection operation is started. When the heat collection operation is started, first, the temperature difference ON-OFF control by the ON / OFF operation control unit 132 is started, and even if the amount of solar radiation is low, heat is collected and stored (P1). And during this control execution, the present solar radiation amount estimation part 135 estimates the present solar radiation amount (P2). Until it is determined that the current solar radiation amount is sufficient for heating to a temperature equal to or higher than the temperature set as the first target temperature by the target temperature setting unit 133 (normal temperature 40 ° C.), that is, while it is insufficient. The temperature difference ON / OFF control is continued (NO in P2 and P3, P4).
[0040]
When it is determined that the current amount of solar radiation is sufficient for heating to a temperature equal to or higher than the first target temperature, proportional heat collection is performed so that the surface temperature of the collector surface temperature sensor 9 becomes the first target temperature. The proportional heat collection control by the control unit 131 is started (YES in P2 and P3, P5). That is, even if the current solar radiation amount can be heated up to 75 ° C., a low temperature side temperature of 40 ° C. is set as the first target temperature, and proportional heat collection control is performed so as to reach this first target temperature. I do. In this proportional heat collection control, the operation control flow rate (circulation flow rate) is changed and adjusted by subjecting the rotational speed of the circulation pump 7 to FB control so that the detected surface temperature becomes the first target temperature. At this time, if the FB control value exceeds the aforementioned α (L / min), the FB control value is forcibly set to α (L / min) to maintain the stratified heat storage, while the FB control value is suddenly clouded. If the control value is extremely low, less than β (L / min), that is, the amount of solar radiation has suddenly changed so that heat cannot be collected unless the circulating flow rate is controlled to less than β (L / min). In this case, the circulation pump 7 is temporarily turned off (proportional heat collection control is stopped), and the recovery of the solar radiation amount is awaited. By the above, it is continued until the bottom part temperature of the thermal storage tank 2 reaches the normal temperature (40 degreeC) which is 1st target temperature in the state which maintained the change adjustment of circulation flow rate in the stratified flow rate range of (beta)-(alpha) (P6). NO, P5).
[0041]
And if all of the inside of the heat storage tank 2 is filled with the warm water of the first target temperature by executing this proportional heat collection control, that is, the bottom temperature detected by the bottom temperature sensor 10 is gradually accumulated from the top side. If the first target temperature is reached, the amount of solar radiation at that time is estimated again (YES in P6, P7). If the solar radiation amount is not high enough to be heated to a temperature equal to or higher than the second target temperature (for example, 60 ° C.) set next by the target temperature setting unit 133, that is, if the solar radiation amount is insufficient, it is turned ON / OFF. Switching to the temperature difference ON / OFF control by the operation control unit 132, the temperature difference ON / OFF control is continued until the amount of solar radiation reaches the above sufficient level (NO in P8, P9). Conversely, if the amount of solar radiation is sufficient even at the stage where the heat storage of the hot water at the first target temperature is completed, the target temperature of the proportional heat collection control up to that time is changed to the second target temperature, Proportional heat collection control is continued (YES in P8, P10).
[0042]
And although illustration is abbreviate | omitted, if the bottom part temperature of the thermal storage tank 2 reaches | attains the said 2nd target temperature and the thermal storage of 2nd target temperature is completed in all the thermal storage tanks 2, said P7-P10 Similarly to the processing, the target temperature is changed to the third target temperature (75 ° C.) which is the final heat storage temperature, proportional heat collection control is performed, and heat storage at the third target temperature is performed.
[0043]
According to the above, even if the solar radiation amount can be heated to the final heat storage temperature (75 ° C.), first, heat storage is performed at 40 ° C. as the first target temperature, and then at 60 ° C. as the second target temperature. Heat storage, and finally the heat storage at 75 ° C. as the third target temperature is performed, so that the circulation amount of the circulation pump 7 is set with the final heat storage temperature of 75 ° C. as the target temperature from the beginning. Compared with the case of performing proportional control to change and adjust, heat storage in a considerably short time is possible. At that time, in the proportional heat collection control of the present embodiment in which the first to third target temperatures are set as the target temperatures, the operation control flow rate of the circulation pump 7 is limited to the stratified flow rate range. Heat storage (heat storage in a stratified state) is performed, and hot water at the target temperature at that time can be secured very quickly at the top of the heat storage tank 2. Moreover, since the temperature difference ON / OFF control is performed even when the proportional heat collection control is not performed due to insufficient solar radiation, the solar heat utilization efficiency can be sufficiently increased according to the weather conditions. .
[0044]
Second Embodiment
FIG. 5 shows a solar water heater according to the second embodiment of the present invention. In the second embodiment, the solar cell 12 of the first embodiment is omitted and the solar radiation amount detecting means different from the first embodiment is adopted, while the heat collection operation control means having a configuration different from that of the first embodiment is employed. The controller 14 is included. Accordingly, the flow rate sensor 8 as flow rate detection means for detecting the circulating flow rate, which is not provided in the first embodiment, and the collector 3 disposed in the vicinity of the heat storage tank 2 in the return path 5b of the heat collecting circuit 5 are provided. And a return temperature sensor 11 as a first temperature detecting means for detecting the temperature of the heated hot water returned to the heat storage tank 2 (hereinafter referred to as “return temperature”). In addition, since the other component of the said 2nd Embodiment is the structure similar to the thing of 1st Embodiment, the same code | symbol is attached | subjected to the same component and the detailed description is abbreviate | omitted.
[0045]
Similar to the first embodiment, the controller 14 includes an MPU, a memory, and the like, and various controls are performed by executing a program installed in advance and a control circuit. That is, the controller 14 serves as a heat collection operation control means, as shown in FIG. 6, for setting a target temperature in the proportional heat collection control unit 131, the ON / OFF operation control unit 132, and the proportional heat collection control unit 131. A temperature setting unit 141; a calendar unit 142 serving as a seasonal information output unit for timing the current season information and outputting a second target temperature predetermined according to the season information to the target temperature setting unit 141; The amount of solar radiation based on the output from various sensors 8, 10, and 11, and the switching control unit 134 that switches the proportional heat collection control by the proportional heat collection control unit 131 and the temperature difference ON / OFF control by the ON / OFF operation control unit 132. And a solar radiation amount calculating unit 143 constituting a part of the solar radiation amount detecting means for estimating and detecting the above.
[0046]
Similar to the target temperature setting unit 133 of the first embodiment, the target temperature setting unit 141 sequentially changes and sets the target temperature step by step to the higher temperature side such as the first target temperature and the second target temperature. Although configured, it differs from the target temperature setting unit 133 of the first embodiment in that the temperature value acquired from the calendar unit 142 is set as the second target temperature. Specifically, a temperature lower than the hot water temperature (heat storage temperature) that can be heated by the current solar radiation amount obtained by the solar radiation amount estimation unit 135 is set as the first target temperature, and the heat storage at the first target temperature is If completed, a temperature that is intermediate between the first target temperature and the heat storage temperature and is output from the calendar unit 142 is set as the second target temperature of the next stage, and the heat storage at the second target temperature is completed. Then, the said heat storage temperature is set as 3rd target temperature which is final target temperature. At this time, if the heat storage temperature, which is the final target temperature, is 75 ° C., for example, the first target temperature is the normal temperature at which hot water can be supplied without heating in the auxiliary heat source apparatus 100 (FIG. 8) as in the first embodiment. For example, 40 [deg.] C. is set, and a temperature value is set as a second target temperature in consideration of a seasonal variation characteristic described later.
[0047]
The calendar unit 142 grasps at least the current month as seasonal information by counting time, and outputs a temperature value previously associated with the seasonal information to the target temperature setting unit 141. For example, 55 degrees Celsius in the winter season from December to February, 65 degrees Celsius in the summer season from June to August, 60 in the spring season from March to May and autumn in September to November. It is designed to output ℃ respectively.
[0048]
The solar radiation amount calculation unit 143 is based on the circulating flow rate value detected by the flow sensor 8 and the temperature difference obtained by subtracting the bottom temperature detected by the bottom temperature sensor 10 from the return temperature detected by the return temperature sensor 11. The amount of heat collected per unit time is obtained by calculation, and the current amount of solar radiation is estimated and obtained from the correlation between the amount of heat collected and the amount of solar radiation.
[0049]
The heat collection operation control by the controller 14 has the same contents as the controller 13 of the first embodiment except that the setting of the second target temperature is different. That is, as shown in FIG. 4, when the heat collection operation is started, first, the temperature difference ON-OFF control by the ON / OFF operation control unit 132 is started (P1), and the solar radiation amount calculation unit is executed during the execution of the control. The current amount of solar radiation is estimated at 143 (P2). The temperature difference ON / OFF control until it is determined that the current solar radiation amount is sufficient to heat to a temperature equal to or higher than the temperature set as the first target temperature by the target temperature setting unit 141 (normal temperature 40 ° C.). If the current amount of solar radiation is determined to be sufficient for heating to a temperature equal to or higher than the first target temperature, the surface of the collector surface temperature sensor 9 is The proportional heat collection control by the proportional heat collection control unit 131 is started so that the temperature becomes the first target temperature (YES in P2 and P3, P5). With this proportional heat collection control, the adjustment of the circulation flow rate is maintained within the stratified flow rate range of β to α described in the first embodiment, and the bottom temperature of the heat storage tank 2 is the normal temperature (the first target temperature) 40.degree. C.) (NO at P6, P5).
[0050]
And if all of the inside of the heat storage tank 2 is filled with the warm water of the first target temperature by executing this proportional heat collection control, that is, the bottom temperature detected by the bottom temperature sensor 10 is gradually accumulated from the top side. When the first target temperature is reached, the amount of solar radiation at that time is estimated again (YES in P6, P7), and the second target temperature taking into account the current seasonal variation characteristics is acquired from the calendar unit 142 (P11). ). If the amount of solar radiation is not high enough to be heated to a temperature equal to or higher than the second target temperature (for example, 60 ° C. in April), that is, if the amount of solar radiation is insufficient, the ON / OFF operation control unit 132 Switching to temperature difference ON / OFF control, the temperature difference ON / OFF control is continued until the amount of solar radiation reaches the above sufficient level (NO in P8, P9). On the other hand, if the amount of solar radiation is sufficient, the proportional heat collection control target temperature is changed to the second target temperature and the proportional heat collection control is continued (YES in P8, P10). .
[0051]
When the bottom temperature of the heat storage tank 2 reaches the second target temperature and the heat storage of the second target temperature is completed in all of the heat storage tank 2, the target temperature is finally set in the same manner as the processes of P7 to P10. It changes to the 3rd target temperature (75 degreeC) which is heat storage temperature, performs proportional heat collection control, and performs heat storage of 3rd target temperature.
[0052]
According to the above, it is possible to obtain the same operation and effect as in the first embodiment, and in addition, heat storage using the second target temperature that takes into account fluctuation characteristics such as seasonal solar heat in the intermediate stage of staged heat storage. It can be performed. For this reason, first, the hot water of the first target temperature on the low temperature side can be stored quickly, and then the heat storage of the hot water of the second target temperature on the higher temperature side according to the seasonal variation characteristics of solar heat can be efficiently continued. Thereby, stepwise heat storage can be performed more efficiently than in the case where the second target temperature is set uniformly regardless of the season.
[0053]
<Other embodiments>
The present invention is not limited to the first and second embodiments described above, but includes other various embodiments. That is, the solar radiation amount detecting means using the solar cell 12 in the first embodiment may be applied to the second embodiment, or conversely, the solar radiation amount calculating unit 143 in the second embodiment is used. The amount detection means may be applied to the first embodiment.
[0054]
Furthermore, the solar radiation amount detection means 15 using a thermocouple as shown in FIG. 7 may be applied to the first or second embodiment. The solar radiation amount detecting means 15 in FIG. 7 divides the heat receiving area 151 that receives solar solar radiation into four equal parts, and colors the two areas in black with good endotherm, and the other two areas in white that easily reflects heat. In addition, thermocouples 153 are installed in the black areas 152 and 152, respectively, and thermocouples 155 are installed in the white areas 154 and 154, respectively. A potential difference between one set of thermocouples 153 and 153 and the other set of thermocouples 155 and 155 is detected, and the current amount of solar radiation is estimated from the correlation between the potential difference and the amount of solar radiation. It is a thing. The upper side of the heat receiving area 151 is covered with a transparent windshield for wind protection.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a solar water heater according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing the contents of a controller according to the first embodiment.
FIG. 3 is a graph showing the relationship between heat collection efficiency and circulation flow rate.
FIG. 4 is a flowchart showing heat collection control according to the first embodiment and the second embodiment.
FIG. 5 is a schematic diagram showing a solar water heater according to a second embodiment.
FIG. 6 is a block diagram illustrating contents of a controller according to the second embodiment.
FIG. 7 is a plan view showing another form of solar radiation amount detecting means.
FIG. 8 is a schematic diagram showing a relationship between a solar heat utilizing hot water device and an auxiliary heat source device.
[Explanation of symbols]
2 heat storage tank
3 collector (solar collector)
7 Circulation pump
8 Flow rate sensor (flow rate detection means)
9 Collector surface temperature sensor (first temperature detection means)
10 Bottom temperature sensor (second temperature detection means)
11 Return temperature sensor (first temperature detection means)
12 Solar cell (irradiance detection means)
13, 14 Controller (heat collection operation control means)
15 Solar radiation detection means
131 Proportional heat collection controller
132 ON / OFF operation controller
133, 141 Target temperature setting section
135 Insolation estimation unit (Insolation detection means)
142 Calendar section (seasonal information output section)
143 Insolation amount calculation unit (insolation amount detection means)

Claims

A heat collecting operation for forcibly circulating the hot water heated by the solar heat collector and returning to the top of the heat storage tank is performed by supplying the bottom water in the heat storage tank to the solar heat collector by the operation of the circulation pump, and In a solar water heater configured to store solar heat as hot water for a heat storage tank,
A solar radiation amount detecting means for detecting an amount of solar radiation received by the solar heat collector; a first temperature detecting means for detecting a temperature of hot water to be returned from the solar heat collector to the top of the heat storage tank; Heat collection operation control means for performing heat collection operation control by operating the circulation pump so that the temperature detected by the temperature detection means becomes a target temperature,
The heat collection operation control unit has a target temperature setting unit that sets a target temperature based on the amount of solar radiation detected from the solar radiation amount detection unit, and the target temperature setting unit stores heat stored in a relationship with the detected amount of solar radiation. A temperature lower than the temperature is first set as a target temperature, and thereafter, the target temperature is changed and set stepwise to the heat storage temperature or to a high temperature side temperature in a range up to the heat storage temperature. A solar water heater.

A heat collecting operation for forcibly circulating the hot water heated by the solar heat collector and returning to the top of the heat storage tank is performed by supplying the bottom water in the heat storage tank to the solar heat collector by the operation of the circulation pump, and In a solar water heater configured to store solar heat as hot water for a heat storage tank,
A solar radiation amount detecting means for detecting an amount of solar radiation received by the solar thermal combustor, a first temperature detecting means for detecting a temperature of hot water to be returned from the solar heat collector to the top of the heat storage tank, and the first temperature Heat collection operation control means for performing heat collection operation control by operating the circulation pump so that the temperature detected by the detection means becomes a target temperature,
The heat collection operation control means outputs a target temperature based on a seasonal information output unit that outputs information related to the current season by timing, and a detected solar radiation amount from the solar radiation amount detection means or seasonal information from the seasonal information output unit. A target temperature setting unit to set,
The target temperature setting unit first sets a temperature lower than the heat storage temperature determined in relation to the detected amount of solar radiation as a target temperature, and thereafter sets the target temperature in advance according to the season information from the season information output unit. The solar water heater is configured to change and set to a high temperature.

It is a solar-heat-use hot water apparatus of Claim 1 or Claim 2 ,
The circulation pump is composed of a variable flow pump,
The heat collection operation control means is configured such that the operation control flow rate by the circulation pump is set in advance as a low flow rate range in which two or more layers having a temperature difference are formed from the bottom to the top in the heat storage tank. A solar-heated hot water device configured to change and adjust by proportional control so that the detected temperature becomes a target temperature while being limited within a range.

It is a solar-heat-use hot water apparatus in any one of Claims 1-3 ,
A second temperature detecting means for detecting the temperature of the water or warm water at the bottom of the heat storage tank;
The heat collection operation control means is configured to intermittently turn the circulation pump ON / OFF at a predetermined flow rate according to the difference between the detected temperatures of the first temperature detection means and the second temperature detection means by the start of the heat collection operation. the temperature difference oN · OFF operation control to operate first run, then, by you start the operation control of the circulation pump based on the target temperature is urchin structure, solar thermal water heater.

It is a solar-heat-use hot water apparatus in any one of Claims 1-4 ,
The solar radiation amount detecting means includes a solar cell disposed on the surface of the solar heat collector, and is configured to detect and detect the solar radiation amount based on the amount of power generated by the solar cell. apparatus.

It is a solar-heat-use hot water apparatus in any one of Claims 1-4 ,
A flow rate detection means for detecting a circulation flow rate by the operation of the circulation pump, and a second temperature detection means for detecting the temperature of water or hot water at the bottom of the heat storage tank,
The solar radiation amount detecting means is based on a heat collection amount obtained by multiplying a detected flow rate by the flow rate detecting means and a temperature difference between both detected temperatures by the first and second temperature detecting means. A solar thermal water heater configured to estimate and detect the amount.

It is a solar-heat-use hot water apparatus in any one of Claims 1-6 ,
The first temperature detecting means detects either the surface temperature of the solar heat collector during forced circulation or the temperature of circulating water in the solar heat collector, or the temperature of hot water returned from the solar heat collector to the top of the heat storage tank. Solar water-based hot water device.