JP3813746B2 - Refrigeration system using hydrogen storage alloy - Google Patents
Refrigeration system using hydrogen storage alloy Download PDFInfo
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- JP3813746B2 JP3813746B2 JP27131498A JP27131498A JP3813746B2 JP 3813746 B2 JP3813746 B2 JP 3813746B2 JP 27131498 A JP27131498 A JP 27131498A JP 27131498 A JP27131498 A JP 27131498A JP 3813746 B2 JP3813746 B2 JP 3813746B2
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A30/00—Adapting or protecting infrastructure or their operation
- Y02A30/27—Relating to heating, ventilation or air conditioning [HVAC] technologies
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/62—Absorption based systems
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
- Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
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- Sorption Type Refrigeration Machines (AREA)
- Hydrogen, Water And Hydrids (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、水素吸蔵合金を用いた冷凍システムに関し、特に、太陽熱や産業廃熱等の熱源を利用して−２０℃以下の冷熱を発生することが可能な冷凍システムに関するものである。
【０００２】
【従来の技術】
近年のエネルギー事情や環境問題から、これまでは放置されていた無尽蔵の太陽熱や産業廃熱を有効に利用することは、産業面における大きな課題であると同時に社会的な要請である。このような状況において、水素吸蔵合金を用いた様々な冷凍システム(ヒートポンプ)が提案されている。
【０００３】
図４は、平衡水素圧力の高い低温用水素吸蔵合金ＭＨ２と平衡水素圧力の低い高温用水素吸蔵合金ＭＨ１とを用いた冷凍システムにおける基本的な冷凍サイクル(▲４▼→▲１▼→▲２▼→▲３▼→▲４▼)を表わしている。先ず、熱源によって高温用水素吸蔵合金ＭＨ１を状態▲４▼から状態▲１▼まで加熱して、水素を放出させる。放出された水素は、状態▲２▼の低温用水素吸蔵合金ＭＨ２に吸収され、これによって発生する熱は、冷媒によって外部へ放出される。次に、高温用水素吸蔵合金ＭＨ１を状態▲４▼の温度に設定すると共に、低温用水素吸蔵合金ＭＨ２を状態▲３▼の温度に設定すると、低温用水素吸蔵合金ＭＨ２の圧力が高温用水素吸蔵合金ＭＨ１の圧力よりも高くなり、低温用水素吸蔵合金ＭＨ２は、吸収していた水素を放出して冷却され(状態▲３▼)、放出された水素は、状態▲４▼の高温用水素吸蔵合金ＭＨ１に吸収される。
この様に、▲４▼→▲１▼→▲２▼の再生過程と▲２▼→▲３▼→▲４▼の冷凍過程とを交互に繰り返すことによって、連続的に冷熱を発生させる冷凍サイクルが構成される。
【０００４】
例えば、特公昭６２−１１８８号公報には、室内の冷暖房に利用可能な冷暖房装置が提案されている。特許第２６５２４５６号公報には、水冷式熱交換器を使用して冷凍温度域(−２０℃以下)の出熱を行なう熱利用システムが提案されている。又、特開平５−１５７３９８号公報には、３種類の水素吸蔵合金を用いて２重の熱サイクルを構成し、冷凍温度域(−２０℃以下)の出熱を行なう冷熱発生装置が提案されている。
【０００５】
【発明が解決しようとする課題】
しかしながら、特公昭６２−１１８８号公報の冷暖房装置は、冷凍温度域(−２０℃以下)の冷熱を発生することは出来ない。これに対し、特許第２６５２４５６号公報の熱利用システムは冷凍温度域(−２０℃以下)の冷熱発生は可能であるが、水や電気等が必要なため、立地条件に制約が生じる問題がある。又、特開平５−１５７３９８号公報の冷熱発生装置は、冷凍温度域(−２０℃以下)の冷熱発生は可能であるが、構造が複雑になりやすく、然も、冷房出力(Ｘ)と熱源入力(Ｙ)との比(＝Ｘ／Ｙ)で表される成績係数(ＣＯＰ：Coefficient of Performance)が０.２程度に留まり、実用的な成績係数(例えば０.３以上)を得ることは困難である。
【０００６】
そこで本発明の目的は、構造が簡易であり、高い成績係数を得ることが可能な１重サイクルの冷凍システムにおいて、−２０℃以下の冷熱発生を実現することである。
尚、１重サイクルとは、２種類の水素吸蔵合金を用いて、両合金間で単一の熱サイクルを構成するものをいう。
【０００７】
【課題を解決する為の手段】
本発明者らは、上記課題を解決するべく鋭意研究を重ねた結果、１重サイクルの冷凍システムの出力特性は、高温用及び低温用の２種類の水素吸蔵合金の平衡水素圧力と、水素を可逆的に吸収、放出する際の反応の容易性を表わす反応可逆性とによって大きく左右され、従来の冷凍システムにおいては、水素吸蔵合金の反応可逆性が低いために、−２０℃以下の冷熱発生が不可能であったことを究明した。
尚、合金の反応可逆性の指標として、ＨＳ値を採用することが出来る。ＨＳ値は、例えば図３に示す如きＰ−Ｃ−Ｔ曲線を有する水素吸蔵合金の場合、ある一定量(例えば０.８ｗｔ％)の水素を吸放出させるのに必要な水素吸収曲線上の圧力Ｐａと水素放出曲線上の圧力Ｐｄの自然対数の差の最小値として、下記数１によって定義することが出来る。
【０００８】
【数１】
ＨＳ＝［ｌｎ(Ｐａ／Ｐｄ)］min
【０００９】
図１は、水素吸収時と水素放出時でＰ−Ｃ−Ｔ特性曲線に差が生じる実際の水素吸蔵合金の特性を考慮して、前述の冷凍サイクルの状態変化を表わしたものである。図中において、実線は、水素放出時の水素圧力と温度の関係(圧力−温度特性)を表わし、破線は、水素吸収時の水素圧力と温度の関係(圧力−温度特性)を表わしている。又、細線は、ＨＳ値が０.６と大きい場合の水素吸放出時の圧力−温度特性を表わし、太線は、ＨＳ値が０.３と小さい場合の水素吸放出時の圧力−温度特性を表わしている。
【００１０】
図１に示す様に、ＨＳ値を減少させることによって、高温用水素吸蔵合金ＭＨ１では、水素吸収時の圧力−温度特性が細破線から太破線にシフトし、水素の吸放出に必要な圧力差はΔＰａ′からΔＰａに低下する。又、低温用水素吸蔵合金ＭＨ２では、水素放出時の圧力−温度特性が細実線から太実線にシフトし、水素の吸放出に必要な圧力差はΔＰｂ′からΔＰｂに低下する。
従って、状態▲２▼の低温用水素吸蔵合金ＭＨ２が水素を放出する冷却過程で、ＨＳ値が０.６と大きい(反応可逆性が低い)ときは、細実線上の状態▲３▼まで温度低下するのに対し、ＨＳ値が０.３と小さい(反応可逆性が高い)ときは、太実線上の状態▲３▼′まで温度低下し、状態▲３▼の温度よりもΔＴ(例えば２０ｄｅｇ)だけ温度が低くなる。
尚、低温用水素吸蔵合金から放出された水素は、ＨＳ値が０.６と大きい(反応可逆性が低い)ときは、細破線上の状態▲４▼の高温用水素吸蔵合金ＭＨ１に吸収されるのに対し、ＨＳ値が０.３と小さい(反応可逆性が高い)ときは、太破線上の状態▲４▼′の高温用水素吸蔵合金ＭＨ１に吸収されることになる。
上述の如く、低温用水素吸蔵合金と高温用水素吸蔵合金のＨＳ値を出来るだけ小さく抑えることによって、より低温の冷熱を発生させることが出来る。
【００１１】
具体的には、本発明に係る水素吸蔵合金を用いた冷凍システムは、太陽熱や産業廃熱の利用によって実現可能な１００〜１５０℃の温度を有する熱源と、外気を用いた空冷によって実現可能な２０〜３５℃の温度を有する熱媒体とを用いて、−２０℃レベルの冷熱の発生を可能とするものである。ここで熱媒体は、熱伝達に用いる媒体、即ち冷媒及び熱媒の総称である。
この場合、冷凍システムの出熱特性に影響する２つの要素、(１)高温用及び低温用の水素吸蔵合金の平衡水素圧力と、(２)各合金の反応可逆性とを考慮する必要がある。
即ち、低温用水素吸蔵合金が、出熱温度である−２０℃レベルで作動可能な圧力(０.０１ＭＰａ以上)を示すこと、空冷式熱交換器を用いて得られる熱媒体の温度により、熱源温度にある高温用水素吸蔵合金から低温用水素吸蔵合金へ水素が移動することが必要である。更に、合金の反応可逆性が低いと熱損失が生じて出熱特性が悪化するため、−２０℃以下の冷熱を発生するには、ＨＳ値が０.３以下であることが必要である。
【００１２】
上述の条件を満たすことが可能な冷凍サイクルとしては、低温用水素吸蔵金及び高温用水素吸蔵合金のＨＳ値がそれぞれ０.３以下の高い反応可逆性を示し、且つ、平衡水素圧力が、高温用水素吸蔵合金については熱源温度域の１００〜１５０℃にて０.８〜１.０ＭＰａ、空冷式熱交換器により得られる冷媒温度である２０〜３５℃にて０.０２〜０.０５ＭＰａ、低温用水素吸蔵合金については空冷式熱交換器により得られる冷媒温度である２０〜３５℃にて０.６〜０.９ＭＰａ、冷熱発生域の−２０〜−２５℃にて０.０５〜０.０７ＭＰａとなるサイクルを構成することが出来る(図１参照)。
【００１３】
この様なサイクルを実現するべく、本発明においては、低温用水素吸蔵合金については、ＴｉＭｎ2をベースとした多成分化によって、所望の平衡水素圧力と高い反応可逆性を併せ持つ合金組成を得ると共に、該合金組成を有する溶湯をロール急冷法若しくはガスアトマイズ法によって急冷し、合金組織の均質化を図った。
具体的には、低温用水素吸蔵合金は、組成式：
(ＴｉaＺｒ1-a)x(Ｍｎ2-b-cＶbＮｉc)y
但し、
０．８≦ａ≦０．９５
０．３≦ｂ≦０．５
０．５５≦ｃ≦０．６５
１．８≦ｙ／ｘ≦２．２
で表わされる。
【００１４】
又、高温用水素吸蔵合金については、ＬａＮｉ5系合金をベースとして組成の調整を行ない、該組成を有する溶湯をロール急冷法によって急冷し、合金組織の均質化を図った。
具体的には、高温用水素吸蔵合金は、組成式：
Ｌａx(Ｎｉ5-a-bＳｎaＡｌb)y
但し、
０．１≦ａ≦０．２５
０．１≦ｂ≦０．２
４．５≦ｙ／ｘ≦５．３
で表わされる。
【００１５】
この様にして作製された高い反応可逆性と適正な平衡水素圧力を有する水素吸蔵合金を用いることによって、構造が簡易で成績係数が高く、然も、冷媒又は熱媒の冷却に外気による空冷を採用することが可能な冷凍システムを実現することが出来る。
【００１６】
【発明の効果】
本発明によれば、水素吸蔵合金を利用した１重サイクルの冷凍システムにおいて、１００〜１５０℃の熱源と空冷式熱交換器により２０〜３５℃に冷却された熱媒体とを用いて、−２０℃レベルの冷熱を発生させることが出来る。
【００１７】
【発明の実施の形態】
以下、本発明を図５に示す冷凍システムに実施した形態について具体的に説明する。
該冷凍システムにおいては、ヒートポンプ装置(１)に対して、熱媒切換え装置(２)を介して集熱器(４)と空冷式熱交換器(６)とが切り換え可能に接続されると共に、冷媒切換え装置(３)を介して空冷式熱交換器(５)と冷凍庫(７)とが切り換え可能に接続され、集熱器(４)と熱媒切換え装置(２)の間には、蓄熱槽(９)が介在している。
【００１８】
ヒートポンプ装置(１)は、第１ヒートポンプＰ１及び第２ヒートポンプＰ２を併設して構成されている。第１ヒートポンプＰ１は、平衡水素圧力の低い水素吸蔵合金ＭＨ１を内蔵した高温側第１反応容器(11)と平衡水素圧力の高い水素吸蔵合金ＭＨ２を内蔵した低温側第１反応容器(12)とを連結管(17)を介して互いに連結してなり、連結管(17)にはバルブ(15)が介在している。又、第２ヒートポンプＰ２は、平衡水素圧力の低い水素吸蔵合金ＭＨ１を内蔵した高温側第２反応容器(13)と平衡水素圧力の高い水素吸蔵合金ＭＨ２を内蔵した低温側第２反応容器(14)とを連結管(18)を介して連結してなり、連結管(18)にはバルブ(16)が介在している。
【００１９】
熱媒切換え装置(２)は、蓄熱槽(９)から伸びる熱媒供給管(41)及び熱媒戻り管(42)を高温側第１反応容器(11)と高温側第２反応容器(13)の何れか一方に接続すると共に、空冷式熱交換器(６)から伸びる熱媒供給管(61)及び熱媒戻り管(62)を他方の反応容器に接続するための配管系と、該配管系に介在する複数の３方弁とから構成される。
又、冷媒切換え装置(３)は、空冷式熱交換器(５)から伸びる冷媒供給管(51)及び冷媒戻り管(52)を低温側第１反応容器(12)と低温側第２反応容器(14)の何れか一方に接続すると共に、冷凍庫(７)から伸びる冷媒戻り管(71)及び冷媒供給管(72)を他方の反応容器に接続するための配管系と、該配管系に介在する複数の４方弁とから構成される。
【００２０】
集熱器(４)は、ヒートパイプ構造を有する複数本の集熱管を併設して構成され、約１４０℃の熱媒(加圧水)の供給が可能である。
集熱器(４)から伸びる熱媒出口管(43)及び熱媒入口管(44)は蓄熱槽(９)へ接続されると共に、熱媒出口管(43)は３方弁(91)を介して熱媒入口管(44)へ接続されており、集熱器(４)から供給される熱媒が約１４０℃に達したとき、熱媒出口管(43)から３方弁(91)を経て蓄熱槽(９)へ高温(約１４０℃)の熱媒が供給される。これによって蓄熱槽(９)に十分な熱が蓄えられ、該蓄熱槽(９)から熱媒供給管(41)を経てヒートポンプ装置(１)へ一定温度(約１４０℃)の熱媒が供給されるのである。
又、空冷式熱交換器(５)(６)は、冷媒(メチルアルコール)又は熱媒(加圧水)をファンによって冷却するものであって、冷媒供給管(51)又は熱媒供給管(61)を経てヒートポンプ装置(１)へ２０℃〜３５℃の冷媒が供給される。
【００２１】
低温用水素吸蔵合金は、Ｔｉ、Ｚｒ、Ｍｎ、Ｖ、及びＮｉを含有したＣ１４型構造を有し、組成式：
(ＴｉaＺｒ1-a)x(Ｍｎ2-b-cＶbＮｉc)y
但し、
０．８≦ａ≦０．９５
０．３≦ｂ≦０．５
０．５５≦ｃ≦０．６５
化学量論比：１．８≦ｙ／ｘ≦２．２
で表わされる。
【００２２】
一方、前記高温用水素吸蔵合金は、Ｌａ、Ｎｉ、Ｓｎ、及びＡｌを含有したＣａＣｕ5型構造を有し、組成式：
Ｌａx(Ｎｉ5-a-bＳｎaＡｌb)y
但し、
０．１≦ａ≦０．２５
０．１≦ｂ≦０．２
化学量論比：４．５≦ｙ／ｘ≦５．３
で表わされる。
【００２３】
低温用水素吸蔵合金及び高温用水素吸蔵合金は、上記組成を有する２種類の水素吸蔵合金の溶湯を回転ロール急冷法若しくはガスアトマイズ法により急冷して作製され、０.８ｗｔ％の水素を２つの平衡水素圧力の差で吸収若しくは放出させるのに必要な２つの平衡水素圧力の自然対数の差の最小値(ＨＳ値)が０.３以下に設定されている。
【００２４】
図５に示す冷凍システムにおいては、集熱器(４)が熱源、空冷式熱交換器(５)及び空冷式熱交換器(６)が放熱源、冷凍庫(７)が冷凍負荷となって、冷凍サイクルが構成される。
例えば、第１ヒートポンプＰ１においては、先ず、高温側第１反応容器(11)内の水素吸蔵合金ＭＨ１が加熱されることによって、水素が放出し、放出された水素は低温側第１反応容器(12)へ送り込まれて、水素吸蔵合金ＭＨ２に吸収される。ここで、水素吸蔵合金ＭＨ２が水素を吸収することによって発生する熱は、空冷式熱交換器(５)から放熱される。
次に、冷媒切換え装置(３)の切換えによって、低温側第１反応容器(12)には冷凍庫(７)が接続される。この状態で、低温側第１反応容器(12)では、水素吸蔵合金ＭＨ２に吸収されている水素が放出し、これによって、冷凍庫(７)から冷媒戻り管(71)を経て供給される冷媒が冷却され、低温(−２０℃以下)の冷媒が冷媒供給管(72)を経て冷凍庫(７)へ送り込まれる。
又、熱媒切換え装置(２)の切換えによって、高温側第１反応容器(11)には空冷式熱交換器(６)が接続される。この状態で、低温側第１反応容器(12)から放出されるガスは高温側第１反応容器(11)へ送り込まれ、水素吸蔵合金ＭＨ１に吸収される(図１中の▲３▼′→▲４▼′)。ここで、水素吸蔵合金ＭＨ１が水素を吸収することによって発生する熱は、空冷式熱交換器(６)から放熱される。
【００２５】
上述の冷凍サイクルを第１ヒートポンプＰ１と第２ヒートポンプＰ２で１８０度の位相差をもって行なわしめることにより、冷凍庫(７)には連続的に低温の冷媒が供給され、冷凍庫(７)内は、−２０℃以下の低温に保たれるのである。
【００２６】
表１(ａ)(ｂ)は、上記本発明の冷凍システムの開発において、高温用水素吸蔵金及び低温用水素吸蔵合金の組成を調整する過程で作製した各種合金の製造方法、ＨＳ値、ＨＳ値算出の基礎となる有効水素移動量、及び平衡水素圧力を表わしている。尚、製造方法の「アーク溶解」は、アーク炉中で溶解させた合金溶湯を徐冷してインゴットを作製する工程、又、「溶湯急冷」は溶湯をロール急冷法によって急冷してインゴットを作製する工程、「熱処理」は、インゴットを１０００℃前後に加熱した後、徐冷を施す工程を表わしている。
【００２７】
【表１】
表１(ａ)に示す様に高温用水素吸蔵合金については、ベースとなるＬａＮｉ5合金では、ＨＳ値が０.３と反応可逆性が高いが、所望の平衡水素圧力を得ることが出来ない。しかし、組成を調整したＬａＮｉ4.7Ｓｎ0.2Ａｌ0.1合金の溶湯をロール急冷法によって急冷した後、８００℃で８時間の熱処理を施することによって、ＨＳ値０.３０の反応可逆性と、１４０℃で所望の平衡水素圧力１ＭＰａが得られている。
又、表１(ｂ)に示す様に低温用水素吸蔵合金については、ベースとなるＴｉＭｎ2系合金の多成分化とロール急冷法による急冷処理によって、Ｔｉ0.85Ｚｒ0.15Ｍｎ1.0Ｖ0.4Ｎｉ0.6合金では、ＨＳ値０ . ３の反応可逆性と、−２０℃で所望の平衡水素圧力０.０６ＭＰａが得られている。
【００２９】
本発明に係る冷凍システムの性能を実証すべく、実施例となる水素吸蔵合金と比較例となる水素吸蔵合金を用いて図５に示す冷凍システムの実験機を作製し、これらの性能比較を行なった。
【００３０】
次に、１つの実施例と６つの比較例における合金組成及び製造方法、冷凍システムの運転条件を示す。
実施例
(１) 高温用水素吸蔵合金(ＭＨ１)
組成：ＬａＮｉ4.7Ｓｎ0.2Ａｌ0.1
製造方法：ロール急冷法による急冷後、８００℃で８時間の熱処理
(２) 低温用水素吸蔵合金(ＭＨ２)
組成：Ｔｉ0.85Ｚｒ0.15Ｍｎ1.0Ｖ0.4Ｎｉ0.6
製造方法：ロール急冷合金
尚、何れの合金についても、各反応容器に充填した合金の重量は２２ｋｇである。又、何れの合金も、有効水素移動量０．８ｗ％でのＨＳ値は０.３である。ここで、有効水素移動量は１５００ｋｃａｌ／ｈの出力を得るために必要な水素の移動量から算出したものである。
比較例１
(１) 高温用水素吸蔵合金(ＭＨ１)
組成：ＬａＮｉ4.55Ａｌ0.45
製造方法：高周波溶解により鋳造後、１０００℃で８時間の熱処理
ＨＳ値：１．０(有効水素移動量０．８ｗｔ％)
(２) 低温用水素吸蔵合金(ＭＨ２)
組成：Ｌａ0.6Ｙ0.4Ｎｉ4.95Ｍｎ0.05
製造方法：高周波溶解により鋳造後、１０００℃で８時間の熱処理
ＨＳ値：１．０(有効水素移動量０．８ｗｔ％)
【００３２】
比較例２
(１) 高温用水素吸蔵合金(ＭＨ１)
組成：ＬａＮｉ4.55Ａｌ0.45
製造方法：高周波溶解により鋳造後、１０００℃で８時間の熱処理
ＨＳ値：１．０(有効水素移動量０．８ｗｔ％)
(２) 低温用水素吸蔵合金(ＭＨ２)
組成：Ｔｉ0.85Ｚｒ0.15Ｍｎ1.0Ｖ0.4Ｎｉ0.6
製造方法：高周波溶解により鋳造後、１０５０℃で８時間の熱処理
ＨＳ値：０．４９(有効水素移動量０．８ｗｔ％)
【００３３】
比較例３
(１) 高温用水素吸蔵合金(ＭＨ１)
組成：ＬａＮｉ4.7Ｓｎ0.2Ａｌ0.1
製造方法：高周波溶解により鋳造後、１１００℃で８時間の熱処理
ＨＳ値：０．６０(有効水素移動量０．８ｗｔ％)
(２) 低温用水素吸蔵合金(ＭＨ２)
組成：Ｌａ0.6Ｙ0.4Ｎｉ4.95Ｍｎ0.05
製造方法：高周波溶解により鋳造後、１０５０℃で８時間の熱処理
ＨＳ値：１．０(有効水素移動量０．８ｗｔ％)
【００３４】
比較例４
(１) 高温用水素吸蔵合金(ＭＨ１)
組成：ＬａＮｉ4.7Ｓｎ0.2Ａｌ0.1
製造方法：高周波溶解により鋳造後、１１００℃で８時間の熱処理
ＨＳ値：０．６０(有効水素移動量０．８ｗｔ％)
(２) 低温用水素吸蔵合金(ＭＨ２)
組成：Ｔｉ0.85Ｚｒ0.15Ｍｎ1.0Ｖ0.4Ｎｉ0.6
製造方法：高周波溶解により鋳造後、１０５０℃で８時間の熱処理
ＨＳ値：０．４９(有効水素移動量０．８ｗｔ％)
【００３５】
比較例５
(１) 高温用水素吸蔵合金(ＭＨ１)
組成：ＬａＮｉ4.7Ｓｎ0.2Ａｌ0.1
製造方法：高周波溶解により鋳造後、１１００℃で８時間の熱処理
ＨＳ値：０．６０(有効水素移動量０．８ｗｔ％)
(２) 低温用水素吸蔵合金(ＭＨ２)
組成：Ｔｉ0.85Ｚｒ0.15Ｍｎ1.0Ｖ0.4Ｎｉ0.6
製造方法：ロール急冷法による急冷
ＨＳ値：０．３０(有効水素移動量０．８ｗｔ％)
【００３６】
比較例６
(１) 高温用水素吸蔵合金(ＭＨ１)
組成：ＬａＮｉ4.7Ｓｎ0.2Ａｌ0.1
製造方法：ロール急冷法により急冷後、８００℃で８時間の熱処理
ＨＳ値：０．３０(有効水素移動量０．８ｗｔ％)
(２) 低温用水素吸蔵合金(ＭＨ２)
組成：Ｔｉ0.85Ｚｒ0.15Ｍｎ1.0Ｖ0.4Ｎｉ0.6
製造方法：高周波溶解により鋳造後、１０５０℃で８時間の熱処理
ＨＳ値：０．４９(有効水素移動量０．８ｗｔ％)
【００３７】
尚、何れの比較例についても、各反応容器に充填した合金の重量は２２ｋｇである。又、有効水素移動量は１５００ｋｃａｌ／ｈの出力を得るために必要な水素の移動量から算出したものである。
【００３８】
図２は、実施例及び比較例１〜６における冷凍システムの出熱特性として、冷熱発生過程における冷媒出口の温度の変化を表わしている。又、表２は、実施例と比較例１〜６における冷凍システムにおける冷熱発生過程１５分後の冷媒出口の温度を示している。
【００４０】
【表２】
図１及び表２から明らかな様に、比較例１〜６では、初期の数分間は−１５℃程度の冷熱を発生しているが、温度が安定化した１５分後以降は、−１０℃レベルの冷熱発生に留まっている。これに対し、本発明の実施例では、温度安定化後においても、−２０℃レベルの冷熱発生を維持している。これは、比較例では、合金の不可逆性に起因する熱損失が大きいために出熱温度の低下を招いているからである。
【００４２】
上述の如く、本発明に係る冷凍システムによれば、１重の熱サイクルを構成した場合においても、１００〜１５０℃の熱源と空冷式熱交換器により冷却された２０〜３５℃の熱媒体とを用いて、−２０℃レベルの冷熱を発生させることが出来る。
【００４３】
尚、本発明の各部構成は上記実施の形態に限らず、特許請求の範囲に記載の技術的範囲内で種々の変形が可能である。例えば、本発明の冷凍システムに用いる水素吸蔵合金は、実施例で示した合金組成や製造方法に限らず、請求項１〜請求項３に記載されている合金組成や製造方法で作製した合金であれば、同等の出熱性能を得ることが出来る。
【図面の簡単な説明】
【図１】本発明に係る冷凍システムにおいてＨＳ値低下の効果を説明する図である。
【図２】本発明の実施例と比較例において冷媒出口温度の変化を表わすグラフである。
【図３】水素吸蔵合金のＰ−Ｃ−Ｔ曲線を表わす図である。
【図４】基本的な冷凍サイクルを表わす図である。
【図５】本発明を実施すべき冷凍システムの構成を表わす系統図である。
【符号の説明】
(１) ヒートポンプ装置
Ｐ１ ヒートポンプ
Ｐ２ ヒートポンプ
(11) 高温側第１反応容器
(12) 低温側第１反応容器
(13) 高温側第２反応容器
(14) 低温側第２反応容器
(２) 熱媒切換え装置
(３) 冷媒切換え装置
(４) 集熱器
(５) 空冷式熱交換器
(６) 空冷式熱交換器
(７) 冷凍庫[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigeration system using a hydrogen storage alloy, and more particularly to a refrigeration system capable of generating cold heat of −20 ° C. or lower using a heat source such as solar heat or industrial waste heat.
[0002]
[Prior art]
Effective utilization of inexhaustible solar heat and industrial waste heat, which has been neglected in the past due to the energy situation and environmental problems in recent years, is a major industrial issue and a social demand. Under such circumstances, various refrigeration systems (heat pumps) using hydrogen storage alloys have been proposed.
[0003]
FIG. 4 shows a basic refrigeration cycle ((4) → (1) → (2) in a refrigeration system using a low temperature hydrogen storage alloy MH2 having a high equilibrium hydrogen pressure and a high temperature hydrogen storage alloy MH1 having a low equilibrium hydrogen pressure. ▼ → ▲ 3 ▼ → ▲ 4 ▼). First, the high-temperature hydrogen storage alloy MH1 is heated from the state (4) to the state (1) with a heat source to release hydrogen. The released hydrogen is absorbed by the low-temperature hydrogen storage alloy MH2 in the state (2), and the heat generated thereby is released to the outside by the refrigerant. Next, when the high temperature hydrogen storage alloy MH1 is set to the temperature of the state (4) and the low temperature hydrogen storage alloy MH2 is set to the temperature of the state (3), the pressure of the low temperature hydrogen storage alloy MH2 is increased to the high temperature hydrogen. The pressure of the storage alloy MH1 becomes higher, and the low-temperature hydrogen storage alloy MH2 releases the absorbed hydrogen and is cooled (state (3)), and the released hydrogen is the high-temperature hydrogen in the state (4). It is absorbed by the storage alloy MH1.
In this way, the refrigeration cycle that continuously generates cold by repeating the regeneration process of (4) → (1) → (2) and the refrigeration process of (2) → (3) → (4) alternately. Is configured.
[0004]
For example, Japanese Patent Publication No. 62-1188 proposes an air conditioning apparatus that can be used for indoor air conditioning. Japanese Patent No. 2652456 proposes a heat utilization system that uses a water-cooled heat exchanger to output heat in a refrigeration temperature range (−20 ° C. or lower). Japanese Laid-Open Patent Publication No. 5-157398 proposes a cold heat generator that forms a double heat cycle using three kinds of hydrogen storage alloys and generates heat in a freezing temperature range (−20 ° C. or lower). ing.
[0005]
[Problems to be solved by the invention]
However, the air conditioning apparatus disclosed in Japanese Patent Publication No. 62-1188 cannot generate cooling in the freezing temperature range (−20 ° C. or lower). On the other hand, although the heat utilization system of Japanese Patent No. 2652456 can generate cold in the freezing temperature range (−20 ° C. or lower), there is a problem that the location conditions are restricted because water, electricity, etc. are required. . In addition, although the cold generator of Japanese Patent Laid-Open No. 5-157398 can generate cold in the freezing temperature range (−20 ° C. or less), the structure is likely to be complicated, and the cooling output (X) and heat source The coefficient of performance (COP) expressed by the ratio to the input (Y) (= X / Y) remains at about 0.2, and a practical coefficient of performance (for example, 0.3 or more) is obtained. Have difficulty.
[0006]
Accordingly, an object of the present invention is to realize generation of cold at −20 ° C. or lower in a single cycle refrigeration system having a simple structure and capable of obtaining a high coefficient of performance.
In addition, a single cycle means what comprises a single heat cycle between both alloys using two types of hydrogen storage alloys.
[0007]
[Means for solving the problems]
As a result of intensive studies to solve the above problems, the present inventors have determined that the output characteristics of the single-cycle refrigeration system are the equilibrium hydrogen pressure of two types of hydrogen storage alloys for high temperature and low temperature, and hydrogen. Refrigerant generation at a temperature of -20 ° C. or lower due to the low reversibility of the hydrogen storage alloy in the conventional refrigeration system, which depends greatly on the reversibility of the reaction, which represents the ease of reaction during reversible absorption and release. I found out that was impossible.
The HS value can be adopted as an index of the reaction reversibility of the alloy. For example, in the case of a hydrogen storage alloy having a P-C-T curve as shown in FIG. 3, the HS value is the pressure on the hydrogen absorption curve necessary to absorb and release a certain amount (for example, 0.8 wt%) of hydrogen. The minimum value of the difference between the natural logarithm of Pa and the pressure Pd on the hydrogen release curve can be defined by the following equation (1).
[0008]
[Expression 1]
HS = [ln (Pa / Pd)] min
[0009]
FIG. 1 shows the above-described change in the state of the refrigeration cycle in consideration of the characteristics of an actual hydrogen storage alloy in which there is a difference in the PCT characteristic curve between hydrogen absorption and hydrogen release. In the figure, the solid line represents the relationship between hydrogen pressure and temperature (pressure-temperature characteristics) during hydrogen release, and the broken line represents the relationship between hydrogen pressure and temperature (pressure-temperature characteristics) during hydrogen absorption. The thin line represents the pressure-temperature characteristic during hydrogen absorption / release when the HS value is as large as 0.6, and the thick line represents the pressure-temperature characteristic during hydrogen absorption / desorption when the HS value is as small as 0.3. It represents.
[0010]
As shown in FIG. 1, by reducing the HS value, in the high-temperature hydrogen storage alloy MH1, the pressure-temperature characteristic during hydrogen absorption shifts from a thin broken line to a thick broken line, and the pressure difference necessary for hydrogen absorption and release Decreases from ΔPa ′ to ΔPa. In the low-temperature hydrogen storage alloy MH2, the pressure-temperature characteristic during hydrogen release shifts from a thin solid line to a thick solid line, and the pressure difference required for hydrogen absorption / release decreases from ΔPb ′ to ΔPb.
Therefore, in the cooling process in which the low-temperature hydrogen storage alloy MH2 in the state (2) releases hydrogen, when the HS value is as large as 0.6 (low reaction reversibility), the temperature reaches the state (3) on the thin solid line. On the other hand, when the HS value is as small as 0.3 (reaction reversibility is high), the temperature decreases to the state (3) on the thick solid line, and ΔT (for example, 20 deg) is higher than the temperature in the state (3). ) Only lower the temperature.
The hydrogen released from the low-temperature hydrogen storage alloy is absorbed by the high-temperature hydrogen storage alloy MH1 in the state (4) on the thin broken line when the HS value is as large as 0.6 (reaction reversibility is low). On the other hand, when the HS value is as small as 0.3 (reaction reversibility is high), it is absorbed by the high-temperature hydrogen storage alloy MH1 in the state (4) 'on the thick broken line.
As described above, by lowering the HS value of the low-temperature hydrogen storage alloy and the high-temperature hydrogen storage alloy as small as possible, it is possible to generate cooler heat at a lower temperature.
[0011]
Specifically, the refrigeration system using the hydrogen storage alloy according to the present invention can be realized by a heat source having a temperature of 100 to 150 ° C. that can be realized by using solar heat or industrial waste heat, and air cooling using outside air. Using a heat medium having a temperature of 20 to 35 ° C., it is possible to generate -20 ° C. cold. Here, the heat medium is a general term for a medium used for heat transfer, that is, a refrigerant and a heat medium.
In this case, it is necessary to consider two factors that affect the heat output characteristics of the refrigeration system, (1) the equilibrium hydrogen pressure of the high-temperature and low-temperature hydrogen storage alloys, and (2) the reversibility of each alloy. .
That is, the low-temperature hydrogen storage alloy exhibits a pressure (over 0.01 MPa or more) at which it can operate at a temperature of −20 ° C. that is the heat output temperature, and the temperature of the heat medium obtained by using an air-cooled heat exchanger It is necessary for hydrogen to move from the high temperature hydrogen storage alloy at temperature to the low temperature hydrogen storage alloy. Furthermore, when the reaction reversibility of the alloy is low, heat loss occurs and the heat output characteristics deteriorate, so that it is necessary for the HS value to be 0.3 or less in order to generate cold heat of -20 ° C or less.
[0012]
As a refrigeration cycle capable of satisfying the above conditions, the low-temperature hydrogen storage gold and the high-temperature hydrogen storage alloy each have a high reaction reversibility of 0.3 or less, and the equilibrium hydrogen pressure is high. For the hydrogen storage alloy for use, the heat source temperature range is 100 to 150 ° C., 0.8 to 1.0 MPa, the refrigerant temperature obtained by the air-cooled heat exchanger is 20 to 35 ° C., 0.02 to 0.05 MPa, As for the low-temperature hydrogen storage alloy, it is 0.6 to 0.9 MPa at 20 to 35 ° C. which is a refrigerant temperature obtained by an air-cooled heat exchanger, and 0.05 to 0 at -20 to −25 ° C. in the cold heat generation region. A cycle of 0.07 MPa can be constructed (see FIG. 1).
[0013]
In order to realize such a cycle, in the present invention, for a low-temperature hydrogen storage alloy, by obtaining a multi-component based on TiMn 2 , an alloy composition having both desired equilibrium hydrogen pressure and high reaction reversibility is obtained. The molten metal having the alloy composition was quenched by a roll quenching method or a gas atomizing method to homogenize the alloy structure.
Specifically, the hydrogen storage alloy for low temperature has the composition formula:
(Ti a Zr 1-a ) x (Mn 2-bc V b Ni c ) y
However,
0.8 ≦ a ≦ 0.95
0.3 ≦ b ≦ 0.5
0.55 ≦ c ≦ 0.65
1.8 ≦ y / x ≦ 2.2
It is represented by
[0014]
In addition, the composition of the high-temperature hydrogen storage alloy was adjusted based on a LaNi 5 alloy, and the molten metal having the composition was quenched by a roll quenching method to homogenize the alloy structure.
Specifically, the high temperature hydrogen storage alloy has the composition formula:
La x (Ni 5-ab Sn a Al b ) y
However,
0.1 ≦ a ≦ 0.25
0.1 ≦ b ≦ 0.2
4.5 ≦ y / x ≦ 5.3
It is represented by
[0015]
By using a hydrogen storage alloy having high reaction reversibility and an appropriate equilibrium hydrogen pressure produced in this way, the structure is simple and the coefficient of performance is high.However, air cooling by the outside air is used for cooling the refrigerant or the heat medium. A refrigeration system that can be employed can be realized.
[0016]
【The invention's effect】
According to the present invention, in a single cycle refrigeration system using a hydrogen storage alloy, a heat source of 100 to 150 ° C. and a heat medium cooled to 20 to 35 ° C. by an air-cooled heat exchanger are used, and −20 It can generate cold heat at the ℃ level.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the embodiment in which the present invention is implemented in the refrigeration system shown in FIG. 5 will be specifically described.
In the refrigeration system, a heat collector (4) and an air-cooled heat exchanger (6) are switchably connected to a heat pump device (1) via a heat medium switching device (2). An air-cooled heat exchanger (5) and a freezer (7) are switchably connected via a refrigerant switching device (3), and a heat storage is provided between the heat collector (4) and the heat medium switching device (2). A tank (9) is interposed.
[0018]
The heat pump device (1) includes a first heat pump P1 and a second heat pump P2. The first heat pump P1 includes a high temperature side first reaction vessel (11) containing a hydrogen storage alloy MH1 having a low equilibrium hydrogen pressure and a low temperature side first reaction vessel (12) containing a hydrogen storage alloy MH2 having a high equilibrium hydrogen pressure. Are connected to each other via a connecting pipe (17), and a valve (15) is interposed in the connecting pipe (17). The second heat pump P2 includes a high temperature side second reaction vessel (13) containing a hydrogen storage alloy MH1 having a low equilibrium hydrogen pressure and a low temperature side second reaction vessel (14) containing a hydrogen storage alloy MH2 having a high equilibrium hydrogen pressure. ) Through a connecting pipe (18), and a valve (16) is interposed in the connecting pipe (18).
[0019]
The heat medium switching device (2) includes a heat medium supply pipe (41) and a heat medium return pipe (42) extending from the heat storage tank (9), the high temperature side first reaction container (11) and the high temperature side second reaction container (13 A piping system for connecting a heating medium supply pipe (61) and a heating medium return pipe (62) extending from the air-cooled heat exchanger (6) to the other reaction vessel, It consists of a plurality of three-way valves interposed in the piping system.
The refrigerant switching device (3) includes a refrigerant supply pipe (51) and a refrigerant return pipe (52) extending from the air-cooled heat exchanger (5), the low temperature side first reaction container (12) and the low temperature side second reaction container. (14) A pipe system for connecting the refrigerant return pipe (71) and the refrigerant supply pipe (72) extending from the freezer (7) to the other reaction vessel and being connected to one of the two, and intervening in the pipe system And a plurality of four-way valves.
[0020]
The heat collector (4) is configured with a plurality of heat collecting tubes having a heat pipe structure, and can supply a heating medium (pressurized water) at about 140 ° C.
The heat medium outlet pipe (43) and the heat medium inlet pipe (44) extending from the heat collector (4) are connected to the heat storage tank (9), and the heat medium outlet pipe (43) is connected to the three-way valve (91). When the heat medium supplied from the heat collector (4) reaches about 140 ° C., the three-way valve (91) from the heat medium outlet pipe (43) is connected to the heat medium inlet pipe (44). After that, a high-temperature (about 140 ° C.) heating medium is supplied to the heat storage tank (9). As a result, sufficient heat is stored in the heat storage tank (9), and a heat medium having a constant temperature (about 140 ° C.) is supplied from the heat storage tank (9) to the heat pump device (1) through the heat medium supply pipe (41). It is.
The air-cooled heat exchangers (5) and (6) cool a refrigerant (methyl alcohol) or a heat medium (pressurized water) with a fan, and include a refrigerant supply pipe (51) or a heat medium supply pipe (61). Then, a refrigerant at 20 ° C. to 35 ° C. is supplied to the heat pump device (1).
[0021]
The hydrogen storage alloy for low temperature has a C14 type structure containing Ti, Zr, Mn, V, and Ni, and has a composition formula:
(Ti a Zr 1-a ) x (Mn 2-bc V b Ni c ) y
However,
0.8 ≦ a ≦ 0.95
0.3 ≦ b ≦ 0.5
0.55 ≦ c ≦ 0.65
Stoichiometric ratio: 1.8 ≦ y / x ≦ 2.2
It is represented by
[0022]
Meanwhile, the high-temperature hydrogen storage alloy has a CaCu 5 type structure containing La, Ni, Sn, and Al, and has a composition formula:
La x (Ni 5-ab Sn a Al b ) y
However,
0.1 ≦ a ≦ 0.25
0.1 ≦ b ≦ 0.2
Stoichiometric ratio: 4.5 ≦ y / x ≦ 5.3
It is represented by
[0023]
The hydrogen storage alloy for low temperature and the hydrogen storage alloy for high temperature are prepared by quenching two types of hydrogen storage alloys having the above composition by a rotating roll quenching method or a gas atomizing method, and 0.8 wt% of hydrogen is balanced between the two. The minimum value (HS value) of the difference between the natural logarithms of the two equilibrium hydrogen pressures required for absorption or release by the difference in hydrogen pressure is set to 0.3 or less.
[0024]
In the refrigeration system shown in FIG. 5, the heat collector (4) is a heat source, the air-cooled heat exchanger (5) and the air-cooled heat exchanger (6) are heat radiation sources, and the freezer (7) is a refrigeration load. A refrigeration cycle is configured.
For example, in the first heat pump P1, first, the hydrogen storage alloy MH1 in the high temperature side first reaction vessel (11) is heated to release hydrogen, and the released hydrogen is discharged to the low temperature side first reaction vessel ( 12) and absorbed by the hydrogen storage alloy MH2. Here, the heat generated by the hydrogen storage alloy MH2 absorbing hydrogen is dissipated from the air-cooled heat exchanger (5).
Next, the freezer (7) is connected to the low temperature side first reaction vessel (12) by switching the refrigerant switching device (3). In this state, in the low temperature side first reaction vessel (12), the hydrogen absorbed in the hydrogen storage alloy MH2 is released, whereby the refrigerant supplied from the freezer (7) via the refrigerant return pipe (71) is discharged. Cooled and low-temperature (−20 ° C. or lower) refrigerant is sent to the freezer (7) through the refrigerant supply pipe (72).
Further, the air-cooled heat exchanger (6) is connected to the high temperature side first reaction vessel (11) by switching the heat medium switching device (2). In this state, the gas released from the low temperature side first reaction vessel (12) is sent to the high temperature side first reaction vessel (11) and absorbed by the hydrogen storage alloy MH1 ((3) in FIG. 1 → (4) '). Here, the heat generated by the hydrogen storage alloy MH1 absorbing hydrogen is radiated from the air-cooled heat exchanger (6).
[0025]
By performing the above-described refrigeration cycle with a phase difference of 180 degrees between the first heat pump P1 and the second heat pump P2, a low-temperature refrigerant is continuously supplied to the freezer (7). It is kept at a low temperature of 20 ° C. or lower.
[0026]
Tables 1 (a) and 1 (b) show the manufacturing method, HS value, and HS of various alloys prepared in the process of adjusting the composition of the hydrogen storage alloy for high temperature and the hydrogen storage alloy for low temperature in the development of the refrigeration system of the present invention. It represents the effective hydrogen transfer amount and the equilibrium hydrogen pressure, which are the basis for the value calculation. In addition, “arc melting” in the manufacturing method is a process in which the molten alloy melted in the arc furnace is gradually cooled to produce an ingot, and “melt quenching” is used to quench the molten metal by a roll quenching method to produce an ingot. The step of “heat treatment” represents a step of gradually cooling the ingot after it is heated to about 1000 ° C.
[0027]
[Table 1]
As shown in Table 1 (a), with regard to the high-temperature hydrogen storage alloy, the base LaNi 5 alloy has a high reversibility with an HS value of 0.3, but the desired equilibrium hydrogen pressure cannot be obtained. . However, a LaNi 4.7 Sn 0.2 Al 0.1 alloy melt whose composition has been adjusted is quenched by a roll quenching method and then subjected to a heat treatment at 800 ° C. for 8 hours, whereby a reaction reversibility with an HS value of 0.30 and 140 ° C. A desired equilibrium hydrogen pressure of 1 MPa is obtained.
Further, as shown in Table 1 (b), for the hydrogen storage alloy for low temperature, Ti 0.85 Zr 0.1 5 Mn 1.0 V 0.4 Ni 0.6 is obtained by multi-component TiMn 2 base alloy as a base and quenching treatment by roll quenching method. the alloy, and the reaction reversibility of HS zero. 3, the desired equilibrium hydrogen pressure 0.06MPa at -20 ° C. is obtained.
[0029]
In order to demonstrate the performance of the refrigeration system according to the present invention, a hydrogen storage alloy as an example and a hydrogen storage alloy as a comparative example were used to produce an experimental machine of the refrigeration system shown in FIG. It was.
[0030]
Next, alloy compositions and manufacturing methods and operating conditions of the refrigeration system in one example and six comparative examples are shown.
Example
(1) High temperature hydrogen storage alloy (MH1)
Composition: LaNi 4.7 Sn 0.2 Al 0.1
Manufacturing method: After quenching by roll quenching method, heat treatment at 800 ° C for 8 hours
(2) Low temperature hydrogen storage alloy (MH2)
Composition: Ti 0.85 Zr 0.15 Mn 1.0 V 0.4 Ni 0.6
Production method: Roll quenched alloy In each alloy, the weight of the alloy filled in each reaction vessel is 22 kg. Further, in any alloy, the HS value at an effective hydrogen transfer amount of 0.8 w% is 0.3. Here, the effective hydrogen transfer amount is calculated from the hydrogen transfer amount necessary to obtain an output of 1500 kcal / h.
Comparative Example 1
(1) High temperature hydrogen storage alloy (MH1)
Composition: LaNi 4.55 Al 0.45
Manufacturing method: Heat treatment at 1000 ° C. for 8 hours after casting by high frequency melting HS value: 1.0 (effective hydrogen transfer amount 0.8 wt%)
(2) Low temperature hydrogen storage alloy (MH2)
Composition: La 0.6 Y 0.4 Ni 4.95 Mn 0.05
Manufacturing method: Heat treatment at 1000 ° C. for 8 hours after casting by high frequency melting HS value: 1.0 (effective hydrogen transfer amount 0.8 wt%)
[0032]
Comparative Example 2
(1) High temperature hydrogen storage alloy (MH1)
Composition: LaNi 4.55 Al 0.45
Manufacturing method: Heat treatment at 1000 ° C. for 8 hours after casting by high frequency melting HS value: 1.0 (effective hydrogen transfer amount 0.8 wt%)
(2) Low temperature hydrogen storage alloy (MH2)
Composition: Ti 0.85 Zr 0.15 Mn 1.0 V 0.4 Ni 0.6
Manufacturing method: After casting by high frequency melting, heat treatment HS value at 1050 ° C. for 8 hours: 0.49 (effective hydrogen transfer amount 0.8 wt%)
[0033]
Comparative Example 3
(1) High temperature hydrogen storage alloy (MH1)
Composition: LaNi 4.7 Sn 0.2 Al 0.1
Manufacturing method: After casting by high frequency melting, heat treatment for 8 hours at 1100 ° C. HS value: 0.60 (effective hydrogen transfer amount 0.8 wt%)
(2) Low temperature hydrogen storage alloy (MH2)
Composition: La 0.6 Y 0.4 Ni 4.95 Mn 0.05
Manufacturing method: After casting by high-frequency melting, heat treatment HS value at 1050 ° C. for 8 hours: 1.0 (effective hydrogen transfer amount 0.8 wt%)
[0034]
Comparative Example 4
(1) High temperature hydrogen storage alloy (MH1)
Composition: LaNi 4.7 Sn 0.2 Al 0.1
Manufacturing method: After casting by high frequency melting, heat treatment for 8 hours at 1100 ° C. HS value: 0.60 (effective hydrogen transfer amount 0.8 wt%)
(2) Low temperature hydrogen storage alloy (MH2)
Composition: Ti 0.85 Zr 0.15 Mn 1.0 V 0.4 Ni 0.6
Manufacturing method: After casting by high frequency melting, heat treatment HS value at 1050 ° C. for 8 hours: 0.49 (effective hydrogen transfer amount 0.8 wt%)
[0035]
Comparative Example 5
(1) High temperature hydrogen storage alloy (MH1)
Composition: LaNi 4.7 Sn 0.2 Al 0.1
Manufacturing method: After casting by high frequency melting, heat treatment for 8 hours at 1100 ° C. HS value: 0.60 (effective hydrogen transfer amount 0.8 wt%)
(2) Low temperature hydrogen storage alloy (MH2)
Composition: Ti 0.85 Zr 0.15 Mn 1.0 V 0.4 Ni 0.6
Production method: quenching HS value by roll quenching method: 0.30 (effective hydrogen transfer amount 0.8 wt%)
[0036]
Comparative Example 6
(1) High temperature hydrogen storage alloy (MH1)
Composition: LaNi 4.7 Sn 0.2 Al 0.1
Production method: After quenching by roll quenching method, heat treatment for 8 hours at 800 ° C. HS value: 0.30 (effective hydrogen transfer amount 0.8 wt%)
(2) Low temperature hydrogen storage alloy (MH2)
Composition: Ti 0.85 Zr 0.15 Mn 1.0 V 0.4 Ni 0.6
Manufacturing method: After casting by high frequency melting, heat treatment HS value at 1050 ° C. for 8 hours: 0.49 (effective hydrogen transfer amount 0.8 wt%)
[0037]
In any comparative example, the weight of the alloy filled in each reaction vessel is 22 kg. The effective hydrogen transfer amount is calculated from the hydrogen transfer amount necessary to obtain an output of 1500 kcal / h.
[0038]
FIG. 2 shows changes in the temperature of the refrigerant outlet during the cold heat generation process as the heat output characteristics of the refrigeration systems in Examples and Comparative Examples 1 to 6. Table 2 shows the refrigerant outlet temperature after 15 minutes of the cold heat generation process in the refrigeration systems in Examples and Comparative Examples 1 to 6.
[0040]
[Table 2]
As is apparent from FIG. 1 and Table 2, in Comparative Examples 1 to 6, cold heat of about −15 ° C. was generated in the initial few minutes, but after −15 minutes after the temperature was stabilized, −10 ° C. It has remained at the level of cold heat generation. On the other hand, in the embodiment of the present invention, the generation of cold at the −20 ° C. level is maintained even after temperature stabilization. This is because in the comparative example, the heat loss due to the irreversibility of the alloy is large, leading to a decrease in the heat output temperature.
[0042]
As described above, according to the refrigeration system of the present invention, even when a single heat cycle is configured, a heat source of 100 to 150 ° C. and a heat medium of 20 to 35 ° C. cooled by an air-cooled heat exchanger Can be used to generate -20 ° C level cold.
[0043]
In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. For example, the hydrogen storage alloy used in the refrigeration system of the present invention is not limited to the alloy composition and manufacturing method shown in the examples, but is an alloy manufactured by the alloy composition and manufacturing method described in
[Brief description of the drawings]
FIG. 1 is a diagram for explaining the effect of lowering the HS value in a refrigeration system according to the present invention.
FIG. 2 is a graph showing changes in refrigerant outlet temperature in an example of the present invention and a comparative example.
FIG. 3 is a diagram showing a PCT curve of a hydrogen storage alloy.
FIG. 4 is a diagram showing a basic refrigeration cycle.
FIG. 5 is a system diagram showing a configuration of a refrigeration system in which the present invention is to be implemented.
[Explanation of symbols]
(1) Heat pump device P1 Heat pump P2 Heat pump
(11) High temperature side first reaction vessel
(12) Low temperature side first reaction vessel
(13) High temperature side second reaction vessel
(14) Low temperature side second reaction vessel
(2) Heat medium switching device
(3) Refrigerant switching device
(4) Heat collector
(5) Air-cooled heat exchanger
(6) Air-cooled heat exchanger
(7) Freezer
Claims (5)
(ＴｉaＺｒ1-a)x(Ｍｎ2-b-cＶbＮｉc)y
但し、
０．８≦ａ≦０．９５
０．３≦ｂ≦０．５
０．５５≦ｃ≦０．６５
１．８≦ｙ／ｘ≦２．２
で表わされると共に、高温用水素吸蔵合金の組成式が、
Ｌａx(Ｎｉ5-a-bＳｎaＡｌb)y
但し、
０．１≦ａ≦０．２５
０．１≦ｂ≦０．２
４．５≦ｙ／ｘ≦５．３
で表わされる請求項１に記載の冷凍システム。The composition formula of the hydrogen storage gold for low temperature is
(Ti a Zr 1-a ) x (Mn 2-bc V b Ni c ) y
However,
0.8 ≦ a ≦ 0.95
0.3 ≦ b ≦ 0.5
0.55 ≦ c ≦ 0.65
1.8 ≦ y / x ≦ 2.2
And the composition formula of the high-temperature hydrogen storage alloy is
La x (Ni 5-ab Sn a Al b ) y
However,
0.1 ≦ a ≦ 0.25
0.1 ≦ b ≦ 0.2
4.5 ≦ y / x ≦ 5.3
The refrigeration system of Claim 1 represented by these.
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| JP27131498A JP3813746B2 (en) | 1998-09-25 | 1998-09-25 | Refrigeration system using hydrogen storage alloy |
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|---|---|---|---|
| JP27131498A JP3813746B2 (en) | 1998-09-25 | 1998-09-25 | Refrigeration system using hydrogen storage alloy |
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| JP3813746B2 true JP3813746B2 (en) | 2006-08-23 |
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