JP2004156848A

JP2004156848A - Heat pump water heater

Info

Publication number: JP2004156848A
Application number: JP2002323456A
Authority: JP
Inventors: Masahiro Ohama; 昌宏尾浜; Takeji Watanabe; 竹司渡辺; Yoshitsugu Nishiyama; 吉継西山; Seiichi Yasuki; 誠一安木; Keijiro Kunimoto; 啓次郎國本; Koji Oka; 浩二岡; Tetsuei Kuramoto; 哲英倉本
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2002-11-07
Filing date: 2002-11-07
Publication date: 2004-06-03
Anticipated expiration: 2022-11-07
Also published as: JP3705261B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump water heater improving efficiency during frost formation operation in regard to a hot water storage type heat pump water heater. <P>SOLUTION: The heat pump water heater is provided with a refrigerant circuit having a compressor 1, a hot-water supply heat exchanger 2, a pressure reducing device 3, and an air heat exchanger 4 absorbing atmospheric heat, a hot-water supply circuit having a hot water storage tank 5, a circulating pump 6, and the hot-water supply heat exchanger 2, a refrigerant circulation amount control means 15 for controlling a refrigerant circulation amount of the refrigerant circuit, and a frost formation detecting means 16 for detecting frost formation to the air heat exchanger 4. Since control of the refrigerant circulation amount is stopped when a predetermined condition is satisfied, the numbers of times of defrosting can be reduced, and highly efficient hot-water supply heating operation is made possible. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明はヒートポンプによる給湯機に関するものである。
【０００２】
【従来の技術】
従来、この種のヒートポンプ給湯機は特許文献１に示すものがある。以下、その構成について図１４を参照しながら説明する。図１４に示すように、圧縮機１、給湯熱交換器２、減圧装置３、空気熱交換器４からなる冷媒循環回路と、貯湯槽５、循環ポンプ６、前記給湯熱交換器２を接続した給湯回路ならなり、前記圧縮機１より吐出された高温高圧の過熱ガス冷媒は給湯熱交換器２に流入し、ここで循環ポンプ６から送られてきた水を加熱する。そして、放熱した冷媒は減圧装置３で減圧され、空気熱交換器４に流入し、ここで大気熱を吸熱して蒸発ガス化し、前記圧縮機１に戻る。
【０００３】
一方、給湯熱交換器２で加熱された湯は前記貯湯槽５の上部に流入し、上から次第に貯湯されていく。この時、給湯熱交換器２の水側出口に設けられた沸き上げ温度検出手段７からの信号で回転数制御手段８は循環ポンプ６の回転数を制御して、給湯熱交換器２の出口水温（沸き上げ温度）をほぼ一定になるように沸き上げる。そして、前記給湯熱交換器２の入口水温が設定値に達すると入水温度検出手段９が検知し、給湯加熱運転を停止する。また、制御手段１０は、外気温度を検出する外気温度検出手段１１と圧縮機１の吐出温度を検出する吐出温度検出手段１２からの信号で、前記吐出温度を所定の吐出温度（目標吐出温度）になるように、減圧装置３の弁開度を制御する。
【０００４】
ところで、外気温度が低いときに、前記空気熱交換器４に霜がつくことがある。上述従来例では言及していないが、この霜を解かす手段として、図１４の一点鎖線のように、圧縮機１の出口と空気熱交換器４の入口とを開閉弁１４を介して連結した除霜回路が知られている。即ち、通常の給湯加熱運転時には開閉弁１４を閉じ、除霜運転時には圧縮機１から吐出された冷媒の熱で空気熱交換器４に付いた霜を解かすために開閉弁１４を開く。
【０００５】
【特許文献１】
特開２０００−３４６４４７号公報
【０００６】
【発明が解決しようとする課題】
しかしながら、上記のような構成では、空気熱交換器４に霜がつき始めた場合にも、吐出温度を所定の吐出温度（目標吐出温度）になるように減圧装置３の弁開度を制御する吐出温度制御を行うので、空気熱交換器４への着霜がより一層促進させることになる。即ち、図１５において、横軸に運転時間をとり、縦軸に減圧装置３の弁開度と空気熱交換器４での冷媒の蒸発温度とを取って、運転時間に対する減圧装置３の弁開度と蒸発温度との変化を示したものである。この図からわかるように、霜がつき始めると空気熱交換器４での熱交換量が減少し、蒸発温度も低下する。そして、それに従って、圧縮機１の吐出温度も低下しようとするので、減圧装置３の弁開度を小さくして、吐出温度を一定に保つ。この繰り返しが連続して起こるので、霜が空気熱交換器４の全面に付着し、蒸発温度が除霜開始温度に比較的短時間のうちに到達する。このため、除霜までの１回の給湯加熱運転時間が短かく、貯湯槽５を全量沸き上げるまでの除霜回数が多くなり、例えば電気料金の安い深夜時間帯では沸き上がらない場合があったので、ランニングコストが高いとか、給湯負荷を満たせなく湯切れが生じるなどの課題があった。また、除霜後の給湯加熱運転では、すぐに目標の沸き上げ温度にならず、低い温度で貯湯槽３の上から貯湯されるので、貯湯されている高温の湯と低温の湯とが混合（湯水混合）し、貯湯槽３の湯温を低下させることになり、結局、貯湯槽３を全量沸き上げたとしても貯湯熱量が少なくり、給湯負荷を満たせなく湯切れが生じることがあった。
【０００７】
上述した図１４の従来例は吐出温度を一定にする場合であるが、この他に、圧縮機１の吸入冷媒の過熱度をほぼ一定にする制御もある（図示せず）。この場合も空気熱交換器４に霜がつき始めると空気熱交換器４での熱交換量が減少し、蒸発温度も低下する。そして、それに従って、圧縮機１の吸入冷媒の過熱度も低下しようとするので、減圧装置３の弁開度を小さくして、吸入冷媒の過熱度をほぼ一定に保つ。この繰り返しが連続して起こるので、霜が空気熱交換器４の全面に付着し、蒸発温度が除霜開始温度に比較的短時間のうちに到達する。だから、この場合も図１４の吐出温度制御をした場合と同様の課題を有する。
【０００８】
本発明は上記課題を解決するもので、外気温度が低く、空気熱交換器４に霜が付く場合の給湯加熱運転の高効率化をはかることを主目的とするものである。
【０００９】
【課題を解決するための手段】
前記従来の課題を解決するために、本発明のヒートポンプ給湯機は、圧縮機と給湯熱交換器と減圧装置と大気熱を吸熱する空気熱交換器とを有する冷媒回路と、貯湯槽と循環ポンプと前記給湯熱交換器とを有する給湯水回路と、前記冷媒回路の冷媒循環量を制御する冷媒循環量制御手段と、前記空気熱交換器への着霜を検出する着霜検出手段とを備え、所定の条件が成立した時に前記冷媒循環量の制御を停止するようにしたものである。
【００１０】
これによって、所定の条件が成立した時に、前記減圧装置の弁開度を制御せず一定とするため、空気熱交換器への着霜の進行を抑えることになり、除霜の回数をへらすことができる。
【００１１】
【発明の実施の形態】
本発明は各請求項に記載の形態で実施できるものであり、請求項１記載の発明は、圧縮機と給湯熱交換器と減圧装置と大気熱を吸熱する空気熱交換器とを有する冷媒回路と、貯湯槽と循環ポンプと前記給湯熱交換器とを有する給湯水回路と、前記冷媒回路の冷媒循環量を制御する冷媒循環量制御手段と、前記空気熱交換器への着霜を検出する着霜検出手段とを備え、所定の条件が成立した時に前記冷媒循環量の制御を停止するため、空気熱交換器への着霜の進行を抑えることになり、除霜の回数をへらすことができる。
【００１２】
請求項２記載の発明は、冷媒循環量制御手段として、圧縮機の吐出温度を検出する吐出温度検出手段と減圧装置とを備え、所定の条件が成立した時に吐出温度の制御を停止するため、空気熱交換器への着霜の進行を抑えることになり、除霜の回数をへらすことができる。
【００１３】
請求項３記載の発明は、冷媒循環量制御手段として、圧縮機の吸入冷媒の過熱度を検出する過熱度検出手段と減圧装置とを備え、所定の条件が成立した時に圧縮機吸入冷媒の過熱度制御を停止するため、空気熱交換器への着霜の進行を抑えることになり、除霜の回数をへらすことができる。
【００１４】
請求項４記載の発明は、所定の条件が成立する場合として、給湯加熱運転時間が所定の時間に達した場合とするので、空気熱交換器への霜の付着が進行する前に冷媒循環量の制御を停止するため、空気熱交換器への着霜の進行を抑えることになり、除霜の回数をへらすことができる。
【００１５】
請求項５記載の発明は、吐出圧力を検出する吐出圧力検出手段を備え、吐出圧力が所定の吐出圧力以下になった場合に冷媒循環量の制御を停止するため、空気熱交換器への着霜の進行を抑えることになり、除霜の回数をへらすことができる。
【００１６】
請求項６の発明は、吐出温度が所定の吐出温度以下になった場合に冷媒循環量の制御を停止するため、空気熱交換器への着霜の進行を抑えることになり、除霜の回数をへらすことができる。
【００１７】
請求項７の発明は、減圧装置の弁開度の変化速度が所定の変化速度以上になった場合に冷媒循環量の制御を停止するため、空気熱交換器への着霜の進行を抑えることになり、除霜の回数をへらすことができる。
【００１８】
請求項８の発明は、蒸発温度の変化速度が所定の変化速度以上になった場合に冷媒循環量の制御を停止するため、空気熱交換器への着霜の進行を抑えることになり、除霜の回数をへらすことができる。
【００１９】
請求項９の発明は、外気温度と蒸発温度との温度差が所定の温度差以上になった場合に冷媒循環量の制御を停止するため、空気熱交換器への着霜の進行を抑えることになり、除霜の回数をへらすことができる。
【００２０】
請求項１０の発明は、電流値が所定の電流値以下になった場合に冷媒循環量の制御を停止するため、空気熱交換器への着霜の進行を抑えることになり、除霜の回数をへらすことができる。
【００２１】
請求項１１の発明は、消費電力が所定の消費電力値以下になった場合に冷媒循環量の制御を停止するため、空気熱交換器への着霜の進行を抑えることになり、除霜の回数をへらすことができる。
【００２２】
【実施例】
以下、本発明の実施例について図面を用いて説明する。
【００２３】
（実施例１）
図１は本発明の実施例１のヒートポンプ給湯機の構成図、図２は同ヒートポンプ給湯機の運転時間に対する減圧装置の弁開度と蒸発温度との変化を示す説明図、図３は同ヒートポンプ給湯機の冷媒循環量制御手段として過熱度検出手段を用いた場合の構成図である。なお、従来例で説明した図１４と同じ構成部材には同一符号を用い説明を省略する。
【００２４】
図１において、１５は冷媒回路を循環する冷媒量を制御する冷媒循環量制御手段、１６は空気熱交換器４への着霜を検出する着霜検出手段である。また、冷媒循環量制御手段１５は、一例として、減圧装置３と吐出温度検出手段１２と制御装置１０とから成り立っている。さらに、着霜検出手段１６として蒸発温度検出手段１７を用いている。
【００２５】
次に動作、作用について説明する。給湯加熱運転時には、制御装置１０は、圧縮機１の吐出温度を検出する吐出温度検出手段１２からの信号で、前記吐出温度を所定の吐出温度（目標吐出温度）になるように、減圧装置３の弁開度を制御する。また、着霜検出手段１６である蒸発温度検出手段１７は空気熱交換器４を循環する冷媒の温度を検出する。そして、着霜検出手段１６である蒸発温度検出手段１７が着霜が進行していることを検出し、かつ、所定の条件が成立すると、冷媒循環量制御手段１５は吐出温度を一定にする制御を停止する。すなわち、減圧装置３の弁開度をそのときの弁開度で一定とする。この場合、所定の条件が成立するとは給湯加熱運転時間が所定の時間以上経過することである。
【００２６】
次に、外気温度が低く、空気熱交換器４への着霜が進行する場合について図２を用いて説明する。図２は横軸に運転時間をとり、縦軸に減圧装置３の弁開度と空気熱交換器４での冷媒の蒸発温度とを取って、運転時間に対する減圧装置３の弁開度と蒸発温度との変化を示したものである。同図中の点線は従来例で説明した図１５の場合であり、実線が本発明の場合である。運転開始とともに着霜が進み、蒸発温度が低下する。そして、従来例の場合は、着霜の進行度合いに関係なく、圧縮機１の吐出温度制御を行うため、減圧装置３の弁開度は運転するに従って小さくなり、運転の途中から蒸発温度が急激に低下し、除霜開始温度に到達する。これに対して、本発明の場合には、所定の時間だけ経過すると減圧装置の弁開度を一定にするので、蒸発温度の低下速度は従来例の点線の場合よりも小さくなる。同図に示すように、除霜運転に入るまでの給湯加熱運転の時間は従来例の場合よりも、本発明の場合の方が長くなることがわかる。
【００２７】
上記のように、空気熱交換器４への着霜を検出する着霜検出手段１６とを備え、所定の条件（給湯加熱運転時間が所定の時間だけ経過）が成立した時に冷媒循環量の制御を停止し、空気熱交換器４への着霜の進行を抑えるため、除霜の回数をへらすことができる。
【００２８】
次に、図１では、冷媒循環量制御手段１５の一例として、減圧装置３と吐出温度検出手段１２と制御装置１０とを用いていたが、他の例を説明する。すなわち、図３に示すように、冷媒循環量制御手段１５として、減圧装置３と過熱度検出手段１８と制御装置１０とを用いた場合である。この場合、過熱度検出手段１８は圧縮機１の吸入冷媒の過熱度を検出し、この値がほぼ一定になるように、制御装置１０は減圧装置３の弁開度を制御する（過熱度制御）。この時も図２で説明したことと同様のことが言える。
【００２９】
なお、過熱度検出手段１８として、圧縮機１の吸入温度を検出する吸入温度検出手段（図示せず）と圧縮機１の吸入圧力を検出する吸入圧力検出手段（図示せず）とを用いて、吸入温度と吸入圧力とから過熱度を演算で求めても良い。
【００３０】
（実施例２）
図４は本発明の実施例２のヒートポンプ給湯機の構成図、図５は同ヒートポンプ給湯機の運転時間に対する吐出圧力と減圧装置の弁開度と蒸発温度との変化を示す説明図である。
【００３１】
本実施例において、図１の実施例１と異なる点は、圧縮機１の吐出圧力を検出する吐出圧力検出手段１９を設けた構成としていることである。なお、実施例１と同符号の部分は同一構成を有し、説明は省略する。
【００３２】
次に動作、作用について説明する。給湯加熱運転時には、制御装置１０は、圧縮機１の吐出温度を検出する吐出温度検出手段１２からの信号で、前記吐出温度を所定の吐出温度（目標吐出温度）になるように、減圧装置３の弁開度を制御する。また、着霜検出手段１６である蒸発温度検出手段１７は空気熱交換器４を循環する冷媒の温度を検出する。そして、着霜検出手段１６である蒸発温度検出手段１７が着霜が進行していることを検出し、かつ、所定の条件が成立すると、冷媒循環量制御手段１５は吐出温度を一定にする制御を停止する。すなわち、減圧装置３の弁開度をそのときの弁開度で一定とする。この場合、所定の条件が成立するとは吐出圧力が所定の吐出圧力以下になることである。
【００３３】
次に、外気温度が低く、空気熱交換器４への着霜が進行する場合について図５を用いて説明する。図５は横軸に運転時間をとり、縦軸に吐出圧力と減圧装置３の弁開度と空気熱交換器４での冷媒の蒸発温度とを取って、運転時間に対する吐出圧力と減圧装置３の弁開度と蒸発温度との変化を示したものである。図５中の点線は従来例で説明した図１５の場合であり、実線が本発明の場合である。運転開始とともに着霜が進み、蒸発温度が低下する。そして、従来例の場合は、着霜の進行度合いに関係なく、圧縮機１の吐出温度制御を行うため、減圧装置３の弁開度は運転するに従って小さくなり、運転の途中から蒸発温度が急激に低下し、除霜開始温度に到達する。これに対して、本発明の場合には、吐出圧力が所定の吐出圧力になると減圧装置の弁開度を一定にするので、蒸発温度の低下速度は従来例の点線の場合よりも小さくなる。同図からわかるように、除霜運転に入るまでの給湯加熱運転の時間は従来例の場合よりも、本発明の場合の方が長くなる。
【００３４】
（実施例３）
図６は本発明の実施例３のヒートポンプ給湯機の構成図、図７は同ヒートポンプ給湯機の運転時間に対する吐出温度と減圧装置の弁開度と蒸発温度との変化を示す説明図である。
【００３５】
本実施例において、実施例１の図３と異なる点は、圧縮機１の吐出温度を検出する吐出温度検出手段１２を設けた構成としていることである。なお、実施例１の図３と同符号の部分は同一構成を有し、説明は省略する。
【００３６】
次に動作、作用について説明する。給湯加熱運転時には、制御装置１０は、過熱度検出手段１８からの信号で圧縮機１の吸入冷媒の過熱度を検出し、この値がほぼ一定になるように、減圧装置３の弁開度を制御する。また、着霜検出手段１６である蒸発温度検出手段１７は空気熱交換器４を循環する冷媒の温度を検出する。そして、着霜検出手段１６である蒸発温度検出手段１７は着霜が進行していることを検出し、かつ、所定の条件が成立すると、冷媒循環量制御手段１５は過熱度をほぼ一定にする制御を停止する。すなわち、減圧装置３の弁開度をそのときの弁開度で一定とする。
【００３７】
この場合、所定の条件が成立するとは、図７に示すように、吐出温度が所定の吐出温度に以下になることである。同図において、横軸に運転時間をとり、縦軸に吐出温度と減圧装置３の弁開度と空気熱交換器４での冷媒の蒸発温度とを取って、運転時間に対する吐出温度と減圧装置３の弁開度と蒸発温度との変化を示したものである。図中の点線は従来例で説明した図１５の場合であり、実線が本発明の場合である。運転開始とともに着霜が進み、蒸発温度が低下する。そして、従来例の場合は、着霜の進行度合いに関係なく、圧縮機１の過熱度制御を行うため、減圧装置３の弁開度は運転するに従って小さくなり、運転の途中から蒸発温度が急激に低下し、除霜開始温度に到達する。これに対して、本発明の場合には、吐出温度が所定の吐出温度に以下になると減圧装置の弁開度を一定にするので、蒸発温度の低下速度は従来例の点線の場合よりも小さくなる。同図からわかるように、除霜運転に入るまでの給湯加熱運転の時間は従来例の場合よりも、本発明の場合の方が長くなる。
【００３８】
上記のように、吐出温度が所定の吐出温度に以下になった時に冷媒循環量の制御を停止し、空気熱交換器への着霜の進行を抑えるため、除霜の回数をへらすことができる。
【００３９】
（実施例４）
図８は本発明の実施例４のヒートポンプ給湯機の運転時間に対する減圧装置の弁開度と蒸発温度との変化を示す説明図である。
【００４０】
本実施例において、実施例１と異なる点は、所定の条件が成立する場合として、減圧装置３の弁開度の変化速度が所定の変化速度以上になった場合としていることである。なお、実施例１と同符号の部分は同一構成を有し、説明は省略する。
【００４１】
次に動作、作用について説明する。図８を用いて、外気温度が低く空気熱交換器４への着霜が進行する場合について説明する。図８は横軸に運転時間をとり、縦軸に減圧装置３の弁開度と空気熱交換器４での冷媒の蒸発温度とを取って、運転時間に対する減圧装置３の弁開度と蒸発温度との変化を示したものである。同図中の点線は従来例で説明した図１５の場合であり、実線が本発明の場合である。運転開始とともに着霜が進み、蒸発温度が低下する。そして、従来例の場合は、着霜の進行度合いに関係なく、圧縮機１の吐出温度制御（または過熱度制御）を行うため、減圧装置３の弁開度は運転するに従って小さくなり、運転の途中から蒸発温度が急激に低下し、除霜開始温度に到達する。この時、空気熱交換器４への着霜が進むほど蒸発温度の低下割合が大きくなり、その分、減圧装置３の弁開度の変更割合も大きくなる。そこで本発明の場合には、減圧装置３の弁開度の変化速度が所定の変化速度以上になった場合に減圧装置の弁開度を一定にするので、蒸発温度の低下速度は従来例の点線の場合よりも小さくなる。同図からわかるように、除霜運転に入るまでの給湯加熱運転の時間は従来例の場合よりも、本発明の場合の方が長くなる。
【００４２】
上記のように、減圧装置３の弁開度の変化速度が所定の変化速度以上になった時に冷媒循環量の制御を停止し、空気熱交換器４への着霜の進行を抑えるため、除霜の回数をへらすことができる。
【００４３】
（実施例５）
図９は本発明の実施例５のヒートポンプ給湯機の運転時間に対する減圧装置の弁開度と蒸発温度との変化を示す説明図である。
【００４４】
本実施例において、実施例１と異なる点は、所定の条件が成立する場合として、蒸発温度の変化速度が所定の変化速度以上になった場合としていることである。なお、実施例１と同符号の部分は同一構成を有し、説明は省略する。
【００４５】
次に動作、作用について説明する。図９を用いて、外気温度が低く空気熱交換器４への着霜が進行する場合について説明する。同図は横軸に運転時間をとり、縦軸に減圧装置３の弁開度と空気熱交換器４での冷媒の蒸発温度とを取って、運転時間に対する減圧装置３の弁開度と蒸発温度との変化を示したものである。同図中の点線は従来例で説明した図１５の場合であり、実線が本発明の場合である。運転開始とともに着霜が進み、蒸発温度が低下する。そして、従来例の場合は、着霜の進行度合いに関係なく、圧縮機１の吐出温度制御（または過熱度制御）を行うため、減圧装置３の弁開度は運転するに従って小さくなり、運転の途中から蒸発温度が急激に低下し、除霜開始温度に到達する。この時、空気熱交換器４への着霜が進むほど蒸発温度の低下割合が大きくなる。そこで本発明の場合には、蒸発温度の変化速度が所定の変化速度以上になった場合に減圧装置の弁開度を一定にするので、蒸発温度の低下速度は従来例の点線の場合よりも小さくなる。同図からわかるように、除霜運転に入るまでの給湯加熱運転の時間は従来例の場合よりも、本発明の場合の方が長くなる。
【００４６】
上記のように、蒸発温度の変化速度が所定の変化速度以上になった時に冷媒循環量の制御を停止し、空気熱交換器４への着霜の進行を抑えるため、除霜の回数をへらすことができる。
【００４７】
（実施例６）
図１０は本発明の実施例６のヒートポンプ給湯機の構成図、図１１は同ヒートポンプ給湯機の運転時間に対する外気温度と蒸発温度との温度差と減圧装置の弁開度と蒸発温度の変化を示す説明図である。
【００４８】
本実施例において、実施例１と異なる点は、外気温度を検出する外気温度検出手段１１を設けたことと、所定の条件が成立する場合として、外気温度と蒸発温度との温度差が所定の温度差以上になった場合としていることである。なお、実施例１と同符号の部分は同一構成を有し、説明は省略する。
【００４９】
次に動作、作用について説明する。図１１を用いて、外気温度が低く空気熱交換器４への着霜が進行する場合について説明する。同図は横軸に運転時間をとり、縦軸に外気温度と蒸発温度との温度差と減圧装置３の弁開度と空気熱交換器４での冷媒の蒸発温度とを取って、運転時間に対する外気温度と蒸発温度との温度差と減圧装置３の弁開度と蒸発温度との変化を示したものである。同図中の点線は従来例で説明した図１５の場合であり、実線が本発明の場合である。運転開始とともに着霜が進み、蒸発温度が低下する。そして、従来例の場合は、着霜の進行度合いに関係なく、圧縮機１の吐出温度制御（または過熱度制御）を行うため、減圧装置３の弁開度は運転するに従って小さくなり、運転の途中から蒸発温度が急激に低下し、除霜開始温度に到達する。この時、空気熱交換器４への着霜が進むほど蒸発温度は低下するが、逆に外気温度と蒸発温度との温度差とは大きくなっていく。そこで本発明の場合には、外気温度と蒸発温度との温度差が所定の温度差以上になった場合に減圧装置の弁開度を一定にするので、蒸発温度の低下速度は従来例の点線の場合よりも小さくなる。同図からわかるように、除霜運転に入るまでの給湯加熱運転の時間は従来例の場合よりも、本発明の場合の方が長くなる。
【００５０】
上記のように、外気温度と蒸発温度との温度差が所定の温度差以上になった時に冷媒循環量の制御を停止し、空気熱交換器４への着霜の進行を抑えるため、除霜の回数をへらすことができる。
【００５１】
（実施例７）
図１２は本発明の実施例７のヒートポンプ給湯機の構成図、図１３は同ヒートポンプ給湯機の運転時間に対する電流値と消費電力値と減圧装置の弁開度と蒸発温度の変化を示す説明図である。
【００５２】
本実施例において、実施例１と異なる点は、圧縮機１の電気特性値を検出する電気特性値検出手段２０を設けたことと、所定の条件が成立する場合として、前記電気特性値が所定の電気特性値以下になった場合としていることである。また、電気特性値としては電流値や消費電力値などがある。なお、実施例１と同符号の部分は同一構成を有し、説明は省略する。
【００５３】
次に動作、作用について説明する。図１３を用いて、外気温度が低く空気熱交換器４への着霜が進行する場合について説明する。同図は横軸に運転時間をとり、縦軸に電流値と消費電力と減圧装置３の弁開度と空気熱交換器４での冷媒の蒸発温度とを取って、運転時間に対する電流値と消費電力と減圧装置３の弁開度と蒸発温度との変化を示したものである。同図中の点線は従来例で説明した図１５の場合であり、実線が本発明の場合である。運転開始とともに着霜が進み、蒸発温度が低下する。そして、従来例の場合は、着霜の進行度合いに関係なく、圧縮機１の吐出温度制御（または過熱度制御）を行うため、減圧装置３の弁開度は運転するに従って小さくなり、運転の途中から蒸発温度が急激に低下し、除霜開始温度に到達する。この時、空気熱交換器４への着霜が進むほど電気特性値である電流値と消費電力値とは減少する。そこで本発明の場合には、電流値が所定の電流値以下になった場合、または、消費電力値が所定の消費電力値以下になった場合に減圧装置の弁開度を一定にするので、蒸発温度の低下速度は従来例の点線の場合よりも小さくなる。同図からわかるように、除霜運転に入るまでの給湯加熱運転の時間は従来例の場合よりも、本発明の場合の方が長くなる。
【００５４】
上記のように、圧縮機１の電気特性値を検出する電気特性値検出手段２０をを備え、電流値が所定の電流値以下になった場合、または、消費電力値が所定の消費電力値以下になった場合に冷媒循環量の制御を停止し、空気熱交換器４への着霜の進行を抑えるため、除霜の回数をへらすことができる。
【００５５】
なお各実施例において、使用する冷媒としては、Ｒ４１０ａ等のフロン系冷媒、プロパン等の炭化水素系冷媒、二酸化炭素冷媒が挙げられる。ヒートポンプサイクルの冷媒を超臨界圧にて二酸化炭素を使用する場合は、従来のフロン系冷媒より地球環境に負荷を与えない物質であることから、環境負荷が少ないヒートポンプ給湯装置とすることが出来る。
【００５６】
【発明の効果】
以上のように、本発明によれば、空気熱交換器に霜が着く着霜運転時に所定の条件が成立した場合に冷媒循環量の制御を停止するため、急激な蒸発温度の低下がないので、高効率の給湯加熱運転が可能となる。また、除霜までの給湯加熱運転の時間も長くでき、除霜の回数を減らすことができるので、貯湯槽内の湯水混合も少なくなり、湯切れが生じることが少なく、ランニングコストも安くすることができるという効果がある。
【図面の簡単な説明】
【図１】本発明の実施例１のヒートポンプ給湯機の構成図
【図２】同ヒートポンプ給湯機の運転時間に対する減圧装置の弁開度と蒸発温度との変化を示す説明図
【図３】同ヒートポンプ給湯機の冷媒循環量制御手段として過熱度検出手段を用いた場合の構成図
【図４】本発明の実施例２のヒートポンプ給湯機の構成図
【図５】同ヒートポンプ給湯機の運転時間に対する吐出圧力と減圧装置の弁開度と蒸発温度との変化を示す説明図
【図６】本発明の実施例３のヒートポンプ給湯機の構成図
【図７】同ヒートポンプ給湯機の運転時間に対する吐出温度と減圧装置の弁開度と蒸発温度との変化を示す説明図
【図８】本発明の実施例４のヒートポンプ給湯機の運転時間に対する減圧装置の弁開度と蒸発温度との変化を示す説明図
【図９】本発明の実施例５のヒートポンプ給湯機の運転時間に対する減圧装置の弁開度と蒸発温度との変化を示す説明図
【図１０】本発明の実施例６のヒートポンプ給湯機の構成図
【図１１】同ヒートポンプ給湯機の運転時間に対する外気温度と蒸発温度との温度差と減圧装置の弁開度と蒸発温度の変化を示す説明図
【図１２】本発明の実施例７のヒートポンプ給湯機の構成図
【図１３】同ヒートポンプ給湯機の運転時間に対する電流値と消費電力値と減圧装置の弁開度と蒸発温度の変化を示す説明図
【図１４】従来例におけるのヒートポンプ給湯機の構成図
【図１５】同ヒートポンプ給湯機の運転時間に対する減圧装置の弁開度と蒸発温度との変化を示す説明図
【符号の説明】
１圧縮機
２給湯熱交換器
３減圧装置
４空気熱交換器
５貯湯槽
６循環ポンプ
１５冷媒循環量制御手段
１６着霜検出手段[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a water heater using a heat pump.
[0002]
[Prior art]
Conventionally, this type of heat pump water heater is disclosed in Patent Document 1. Hereinafter, the configuration will be described with reference to FIG. As shown in FIG. 14, the refrigerant circulation circuit including the compressor 1, the hot water supply heat exchanger 2, the pressure reducing device 3, and the air heat exchanger 4, the hot water storage tank 5, the circulation pump 6, and the hot water supply heat exchanger 2 were connected. The high-temperature and high-pressure superheated gas refrigerant discharged from the compressor 1 flows into the hot water supply heat exchanger 2 and heats the water sent from the circulation pump 6. Then, the radiated refrigerant is depressurized by the decompression device 3 and flows into the air heat exchanger 4 where it absorbs atmospheric heat to evaporate and return to the compressor 1.
[0003]
On the other hand, the hot water heated by the hot water supply heat exchanger 2 flows into the upper portion of the hot water storage tank 5 and is gradually stored from above. At this time, the rotation speed control means 8 controls the rotation speed of the circulation pump 6 by a signal from the boiling temperature detection means 7 provided at the water side outlet of the hot water supply heat exchanger 2, and Boil the water temperature (boiling temperature) so that it is almost constant. Then, when the inlet water temperature of the hot water supply heat exchanger 2 reaches a set value, the incoming water temperature detecting means 9 detects the temperature and stops the hot water supply heating operation. Further, the control means 10 uses the signals from the outside air temperature detection means 11 for detecting the outside air temperature and the discharge temperature detection means 12 for detecting the discharge temperature of the compressor 1 to determine the discharge temperature at a predetermined discharge temperature (target discharge temperature). The valve opening of the pressure reducing device 3 is controlled so that
[0004]
By the way, when the outside air temperature is low, the air heat exchanger 4 may be frosted. Although not mentioned in the above-mentioned conventional example, as a means for resolving this frost, the outlet of the compressor 1 and the inlet of the air heat exchanger 4 are connected via an on-off valve 14 as shown by a dashed line in FIG. Defrost circuits are known. That is, the opening / closing valve 14 is closed during the normal hot water supply heating operation, and the opening / closing valve 14 is opened during the defrosting operation in order to release the frost attached to the air heat exchanger 4 by the heat of the refrigerant discharged from the compressor 1.
[0005]
[Patent Document 1]
JP 2000-34647 A
[0006]
[Problems to be solved by the invention]
However, in the above configuration, even when frost starts to form on the air heat exchanger 4, the valve opening of the pressure reducing device 3 is controlled so that the discharge temperature becomes a predetermined discharge temperature (target discharge temperature). Since the discharge temperature control is performed, frost formation on the air heat exchanger 4 is further promoted. That is, in FIG. 15, the horizontal axis indicates the operation time, and the vertical axis indicates the valve opening degree of the pressure reducing device 3 and the evaporation temperature of the refrigerant in the air heat exchanger 4. It shows the change between the temperature and the evaporation temperature. As can be seen from this figure, when frost begins to form, the amount of heat exchange in the air heat exchanger 4 decreases, and the evaporation temperature also decreases. Then, since the discharge temperature of the compressor 1 also tends to decrease accordingly, the valve opening of the pressure reducing device 3 is reduced to keep the discharge temperature constant. Since this repetition occurs continuously, frost adheres to the entire surface of the air heat exchanger 4, and the evaporation temperature reaches the defrost start temperature in a relatively short time. For this reason, one hot water supply heating operation time until defrosting is short, and the number of times of defrosting until the entire amount of the hot water storage tank 5 is boiled increases. Therefore, there are problems such as a high running cost and running out of hot water because the hot water supply load cannot be satisfied. Further, in the hot water supply heating operation after defrosting, the hot water is not immediately at the target boiling temperature, but is stored from above the hot water storage tank 3 at a low temperature, so that the stored high-temperature hot water and low-temperature hot water are mixed. (Mixing of hot and cold water), and the temperature of the hot water in the hot water storage tank 3 is lowered. As a result, even when the hot water storage tank 3 is entirely boiled, the amount of hot water storage is small, and the hot water supply load may not be satisfied and the hot water may run out. .
[0007]
In the conventional example of FIG. 14 described above, the discharge temperature is kept constant. In addition, there is another control for keeping the degree of superheat of the refrigerant sucked into the compressor 1 substantially constant (not shown). Also in this case, when frost starts to form on the air heat exchanger 4, the amount of heat exchange in the air heat exchanger 4 decreases, and the evaporation temperature also decreases. Then, the degree of superheat of the suction refrigerant of the compressor 1 is also reduced accordingly, so that the degree of opening of the valve of the pressure reducing device 3 is reduced to keep the degree of superheat of the suction refrigerant substantially constant. Since this repetition occurs continuously, frost adheres to the entire surface of the air heat exchanger 4, and the evaporation temperature reaches the defrost start temperature in a relatively short time. Therefore, this case also has the same problem as the case where the discharge temperature control of FIG. 14 is performed.
[0008]
The present invention has been made to solve the above problems, and has as its main object to improve the efficiency of hot water supply heating operation when the outside air temperature is low and the air heat exchanger 4 is frosted.
[0009]
[Means for Solving the Problems]
In order to solve the conventional problems, a heat pump water heater according to the present invention includes a refrigerant circuit having a compressor, a hot water supply heat exchanger, a pressure reducing device, and an air heat exchanger that absorbs atmospheric heat, a hot water tank, and a circulation pump. And a hot water supply circuit having the hot water supply heat exchanger, a refrigerant circulation amount control means for controlling a refrigerant circulation amount of the refrigerant circuit, and a frost detection means for detecting frost formation on the air heat exchanger. When the predetermined condition is satisfied, the control of the refrigerant circulation amount is stopped.
[0010]
Thereby, when a predetermined condition is satisfied, the valve opening of the pressure reducing device is kept constant without being controlled, so that the progress of frost on the air heat exchanger is suppressed, and the number of times of defrosting is reduced. Can be.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention can be embodied in the form described in each claim. The invention described in claim 1 is a refrigerant circuit including a compressor, a hot water supply heat exchanger, a pressure reducing device, and an air heat exchanger that absorbs atmospheric heat. A hot water supply circuit having a hot water storage tank, a circulation pump, and the hot water supply heat exchanger; a refrigerant circulation amount control unit for controlling a refrigerant circulation amount of the refrigerant circuit; and detecting frost on the air heat exchanger. Since the control of the amount of circulating refrigerant is stopped when a predetermined condition is satisfied, the progress of frost on the air heat exchanger is suppressed, and the number of times of defrosting is reduced. it can.
[0012]
The invention according to claim 2 includes, as refrigerant circulation amount control means, a discharge temperature detection means for detecting a discharge temperature of the compressor and a pressure reducing device, and stops the control of the discharge temperature when a predetermined condition is satisfied. The progress of frost formation on the air heat exchanger is suppressed, and the number of times of defrosting can be reduced.
[0013]
According to a third aspect of the present invention, the refrigerant circulation amount control means includes superheat degree detection means for detecting the degree of superheat of the refrigerant sucked into the compressor, and a pressure reducing device. Since the degree control is stopped, the progress of frost formation on the air heat exchanger is suppressed, and the number of times of defrosting can be reduced.
[0014]
According to the fourth aspect of the present invention, since the predetermined condition is satisfied and the hot water supply heating operation time reaches a predetermined time, the amount of refrigerant circulating before the frost adheres to the air heat exchanger progresses. Is stopped, the progress of frost formation on the air heat exchanger is suppressed, and the number of times of defrosting can be reduced.
[0015]
The invention according to claim 5 is provided with a discharge pressure detecting means for detecting a discharge pressure, and stops the control of the refrigerant circulation amount when the discharge pressure becomes equal to or lower than a predetermined discharge pressure. The progress of frost is suppressed, and the number of times of defrosting can be reduced.
[0016]
The invention according to claim 6 stops the control of the refrigerant circulation amount when the discharge temperature becomes equal to or lower than the predetermined discharge temperature, so that the progress of frost formation on the air heat exchanger is suppressed, and the number of times of defrosting is reduced. Can be reduced.
[0017]
The invention according to claim 7 suppresses the progress of frost formation on the air heat exchanger in order to stop the control of the refrigerant circulation amount when the rate of change of the valve opening of the pressure reducing device is equal to or higher than a predetermined rate of change. And the number of times of defrosting can be reduced.
[0018]
According to the invention of claim 8, since the control of the refrigerant circulation amount is stopped when the changing speed of the evaporation temperature becomes equal to or higher than the predetermined changing speed, the progress of frost formation on the air heat exchanger can be suppressed. The frequency of frost can be reduced.
[0019]
According to a ninth aspect of the present invention, the control of the refrigerant circulation amount is stopped when the temperature difference between the outside air temperature and the evaporation temperature becomes equal to or more than a predetermined temperature difference, so that the progress of frost formation on the air heat exchanger is suppressed. And the number of times of defrosting can be reduced.
[0020]
According to the tenth aspect of the present invention, the control of the refrigerant circulation amount is stopped when the current value becomes equal to or less than the predetermined current value, so that the progress of frost on the air heat exchanger is suppressed, and the number of times of defrosting is reduced. Can be reduced.
[0021]
According to the eleventh aspect of the present invention, when the power consumption becomes equal to or less than the predetermined power consumption value, the control of the refrigerant circulation amount is stopped, so that the progress of frost formation on the air heat exchanger is suppressed, and The number can be reduced.
[0022]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0023]
(Example 1)
FIG. 1 is a configuration diagram of a heat pump water heater according to a first embodiment of the present invention, FIG. 2 is an explanatory diagram showing a change in a valve opening degree and an evaporation temperature of a pressure reducing device with respect to an operation time of the heat pump water heater, and FIG. It is a block diagram in the case of using a superheat degree detection means as a refrigerant | coolant circulation amount control means of a water heater. The same components as those in FIG. 14 described in the conventional example are denoted by the same reference numerals, and description thereof is omitted.
[0024]
In FIG. 1, reference numeral 15 denotes refrigerant circulation amount control means for controlling the amount of refrigerant circulating in the refrigerant circuit, and reference numeral 16 denotes frost detection means for detecting frost on the air heat exchanger 4. In addition, the refrigerant circulation amount control unit 15 includes, for example, the pressure reduction device 3, the discharge temperature detection unit 12, and the control device 10. Further, an evaporating temperature detecting means 17 is used as the frost detecting means 16.
[0025]
Next, the operation and operation will be described. At the time of the hot water supply heating operation, the control device 10 uses the signal from the discharge temperature detecting means 12 for detecting the discharge temperature of the compressor 1 to reduce the discharge temperature to a predetermined discharge temperature (target discharge temperature). Of the valve is controlled. Further, the evaporating temperature detecting means 17 serving as the frost detecting means 16 detects the temperature of the refrigerant circulating in the air heat exchanger 4. When the evaporating temperature detecting means 17, which is the frost detecting means 16, detects that frosting is progressing, and when a predetermined condition is satisfied, the refrigerant circulation amount control means 15 controls the discharge temperature to be constant. To stop. That is, the valve opening of the pressure reducing device 3 is made constant at the valve opening at that time. In this case, the predetermined condition is satisfied when the hot water supply heating operation time has passed a predetermined time or more.
[0026]
Next, a case where the outside air temperature is low and frost formation on the air heat exchanger 4 proceeds will be described with reference to FIG. FIG. 2 shows the operation time on the horizontal axis and the valve opening of the pressure reducing device 3 and the evaporation temperature of the refrigerant in the air heat exchanger 4 on the vertical axis. It shows a change with temperature. The dotted line in the figure is the case of FIG. 15 described in the conventional example, and the solid line is the case of the present invention. Frost formation advances with the start of operation, and the evaporation temperature decreases. In the case of the conventional example, since the discharge temperature control of the compressor 1 is performed regardless of the degree of progress of the frosting, the valve opening of the pressure reducing device 3 decreases as the operation proceeds, and the evaporation temperature rapidly increases during the operation. To reach the defrost start temperature. On the other hand, in the case of the present invention, the valve opening of the pressure reducing device is kept constant after a predetermined time has elapsed, so that the rate of decrease of the evaporation temperature is smaller than that in the case of the conventional dotted line. As shown in the figure, it can be seen that the time of the hot water supply heating operation before the defrosting operation is started is longer in the case of the present invention than in the conventional example.
[0027]
As described above, the frost detection means 16 for detecting frost formation on the air heat exchanger 4 is provided, and the control of the refrigerant circulation amount is performed when a predetermined condition (the hot water supply heating operation time has elapsed for a predetermined time) is satisfied. Is stopped, and the progress of frost formation on the air heat exchanger 4 is suppressed, so that the number of times of defrosting can be reduced.
[0028]
Next, in FIG. 1, the pressure reducing device 3, the discharge temperature detecting means 12, and the control device 10 are used as an example of the refrigerant circulation amount control means 15, but another example will be described. That is, as shown in FIG. 3, this is the case where the pressure reducing device 3, the superheat degree detecting device 18, and the control device 10 are used as the refrigerant circulation amount controlling device 15. In this case, the superheat degree detecting means 18 detects the superheat degree of the refrigerant sucked into the compressor 1, and the control device 10 controls the valve opening degree of the pressure reducing device 3 so that this value becomes substantially constant (superheat degree control). ). At this time, the same thing as described with reference to FIG. 2 can be said.
[0029]
As the degree of superheat detection means 18, a suction temperature detection means (not shown) for detecting the suction temperature of the compressor 1 and a suction pressure detection means (not shown) for detecting the suction pressure of the compressor 1 are used. Alternatively, the degree of superheat may be calculated from the suction temperature and the suction pressure.
[0030]
(Example 2)
FIG. 4 is a configuration diagram of a heat pump water heater according to Embodiment 2 of the present invention, and FIG. 5 is an explanatory diagram showing changes in discharge pressure, valve opening degree of a pressure reducing device, and evaporation temperature with respect to operation time of the heat pump water heater.
[0031]
This embodiment is different from the first embodiment in FIG. 1 in that a discharge pressure detecting means 19 for detecting the discharge pressure of the compressor 1 is provided. Note that the portions denoted by the same reference numerals as in the first embodiment have the same configuration, and description thereof will be omitted.
[0032]
Next, the operation and operation will be described. At the time of the hot water supply heating operation, the control device 10 uses the signal from the discharge temperature detecting means 12 for detecting the discharge temperature of the compressor 1 to reduce the discharge temperature to a predetermined discharge temperature (target discharge temperature). Of the valve is controlled. Further, the evaporating temperature detecting means 17 serving as the frost detecting means 16 detects the temperature of the refrigerant circulating in the air heat exchanger 4. When the evaporating temperature detecting means 17, which is the frost detecting means 16, detects that frosting is progressing, and when a predetermined condition is satisfied, the refrigerant circulation amount control means 15 controls the discharge temperature to be constant. To stop. That is, the valve opening of the pressure reducing device 3 is made constant at the valve opening at that time. In this case, the satisfaction of the predetermined condition means that the discharge pressure becomes equal to or lower than the predetermined discharge pressure.
[0033]
Next, a case where the outside air temperature is low and frost formation on the air heat exchanger 4 proceeds will be described with reference to FIG. FIG. 5 shows the operation time on the horizontal axis, the discharge pressure, the valve opening of the pressure reducing device 3 and the evaporation temperature of the refrigerant in the air heat exchanger 4 on the vertical axis. 3 shows changes in the valve opening degree and the evaporation temperature. The dotted line in FIG. 5 is the case of FIG. 15 described in the conventional example, and the solid line is the case of the present invention. Frost formation advances with the start of operation, and the evaporation temperature decreases. In the case of the conventional example, since the discharge temperature control of the compressor 1 is performed regardless of the degree of progress of the frosting, the valve opening of the pressure reducing device 3 decreases as the operation proceeds, and the evaporation temperature rapidly increases during the operation. To reach the defrost start temperature. On the other hand, in the case of the present invention, when the discharge pressure reaches a predetermined discharge pressure, the valve opening of the pressure reducing device is made constant, so that the rate of decrease of the evaporation temperature is smaller than that in the case of the conventional dotted line. As can be seen from the figure, the time of the hot water supply heating operation before the defrosting operation is started is longer in the case of the present invention than in the conventional example.
[0034]
(Example 3)
FIG. 6 is a configuration diagram of a heat pump water heater according to Embodiment 3 of the present invention, and FIG. 7 is an explanatory diagram showing changes in discharge temperature, valve opening degree of a pressure reducing device, and evaporation temperature with respect to operation time of the heat pump water heater.
[0035]
This embodiment is different from the first embodiment in FIG. 3 in that a discharge temperature detecting means 12 for detecting the discharge temperature of the compressor 1 is provided. Note that the portions denoted by the same reference numerals as in FIG. 3 of the first embodiment have the same configuration, and description thereof is omitted.
[0036]
Next, the operation and operation will be described. During the hot water supply heating operation, the control device 10 detects the degree of superheat of the refrigerant sucked into the compressor 1 based on a signal from the degree of superheat detection means 18 and adjusts the valve opening of the pressure reducing device 3 so that this value becomes substantially constant. Control. Further, the evaporating temperature detecting means 17 serving as the frost detecting means 16 detects the temperature of the refrigerant circulating in the air heat exchanger 4. Then, the evaporating temperature detecting means 17 as the frost detecting means 16 detects that the frost is progressing, and when a predetermined condition is satisfied, the refrigerant circulation amount control means 15 makes the superheat degree substantially constant. Stop control. That is, the valve opening of the pressure reducing device 3 is made constant at the valve opening at that time.
[0037]
In this case, the predetermined condition is satisfied when the discharge temperature becomes equal to or lower than the predetermined discharge temperature as shown in FIG. In the figure, the horizontal axis represents the operating time, the vertical axis represents the discharge temperature, the valve opening of the pressure reducing device 3 and the evaporation temperature of the refrigerant in the air heat exchanger 4, and the discharge temperature and the pressure reducing device with respect to the operating time. 3 shows changes in the valve opening and the evaporation temperature. The dotted line in the drawing is the case of FIG. 15 described in the conventional example, and the solid line is the case of the present invention. Frost formation advances with the start of operation, and the evaporation temperature decreases. In the case of the conventional example, since the degree of superheating of the compressor 1 is controlled regardless of the degree of progress of frosting, the valve opening of the pressure reducing device 3 decreases as the operation proceeds, and the evaporation temperature rapidly increases during the operation. To reach the defrost start temperature. On the other hand, in the case of the present invention, when the discharge temperature becomes equal to or lower than the predetermined discharge temperature, the valve opening of the pressure reducing device is kept constant, so that the rate of decrease of the evaporation temperature is smaller than the case of the dotted line in the conventional example. Become. As can be seen from the figure, the time of the hot water supply heating operation before the defrosting operation is started is longer in the case of the present invention than in the conventional example.
[0038]
As described above, when the discharge temperature becomes equal to or lower than the predetermined discharge temperature, the control of the refrigerant circulation amount is stopped, and the number of times of defrosting can be reduced in order to suppress the progress of frost formation on the air heat exchanger. .
[0039]
(Example 4)
FIG. 8 is an explanatory diagram showing changes in the valve opening degree and the evaporation temperature of the pressure reducing device with respect to the operation time of the heat pump water heater of Embodiment 4 of the present invention.
[0040]
This embodiment is different from the first embodiment in that the predetermined condition is satisfied and that the rate of change of the valve opening of the pressure reducing device 3 is equal to or higher than the predetermined rate of change. Note that the portions denoted by the same reference numerals as in the first embodiment have the same configuration, and description thereof will be omitted.
[0041]
Next, the operation and operation will be described. The case where the outside air temperature is low and frost formation on the air heat exchanger 4 proceeds will be described with reference to FIG. FIG. 8 shows the operation time on the horizontal axis, the valve opening of the pressure reducing device 3 and the evaporation temperature of the refrigerant in the air heat exchanger 4 on the vertical axis, and the valve opening and evaporation of the pressure reducing device 3 with respect to the operation time. It shows a change with temperature. The dotted line in the figure is the case of FIG. 15 described in the conventional example, and the solid line is the case of the present invention. Frost formation advances with the start of operation, and the evaporation temperature decreases. In the case of the conventional example, since the discharge temperature control (or superheat control) of the compressor 1 is performed irrespective of the degree of progress of frost formation, the valve opening of the pressure reducing device 3 becomes smaller as it operates, and The evaporation temperature suddenly drops halfway and reaches the defrost start temperature. At this time, as the frost formation on the air heat exchanger 4 progresses, the rate of decrease in the evaporation temperature increases, and accordingly, the rate of change in the valve opening of the pressure reducing device 3 also increases. Therefore, in the case of the present invention, when the rate of change of the valve opening of the pressure reducing device 3 is equal to or higher than a predetermined rate of change, the valve opening of the pressure reducing device is kept constant. It becomes smaller than the case of the dotted line. As can be seen from the figure, the time of the hot water supply heating operation before the defrosting operation is started is longer in the case of the present invention than in the conventional example.
[0042]
As described above, when the rate of change of the valve opening of the pressure reducing device 3 is equal to or higher than a predetermined rate of change, the control of the amount of circulating refrigerant is stopped to suppress the progress of frost on the air heat exchanger 4. The frequency of frost can be reduced.
[0043]
(Example 5)
FIG. 9 is an explanatory diagram showing changes in the valve opening degree and the evaporation temperature of the pressure reducing device with respect to the operation time of the heat pump water heater of Embodiment 5 of the present invention.
[0044]
This embodiment is different from the first embodiment in that a predetermined condition is satisfied and a case where the changing speed of the evaporation temperature is equal to or higher than the predetermined changing speed. Note that the portions denoted by the same reference numerals as in the first embodiment have the same configuration, and description thereof will be omitted.
[0045]
Next, the operation and operation will be described. The case where the outside air temperature is low and frost formation on the air heat exchanger 4 proceeds will be described with reference to FIG. 9. In the figure, the horizontal axis indicates the operation time, and the vertical axis indicates the valve opening degree of the pressure reducing device 3 and the evaporation temperature of the refrigerant in the air heat exchanger 4. It shows a change with temperature. The dotted line in the figure is the case of FIG. 15 described in the conventional example, and the solid line is the case of the present invention. Frost formation advances with the start of operation, and the evaporation temperature decreases. In the case of the conventional example, since the discharge temperature control (or superheat control) of the compressor 1 is performed irrespective of the degree of progress of frost formation, the valve opening of the pressure reducing device 3 becomes smaller as it operates, and The evaporation temperature suddenly drops halfway and reaches the defrost start temperature. At this time, as the frost formation on the air heat exchanger 4 progresses, the rate of decrease in the evaporation temperature increases. Therefore, in the case of the present invention, when the rate of change of the evaporation temperature is equal to or higher than the predetermined rate of change, the valve opening of the pressure reducing device is kept constant. Become smaller. As can be seen from the figure, the time of the hot water supply heating operation before the defrosting operation is started is longer in the case of the present invention than in the conventional example.
[0046]
As described above, when the change rate of the evaporation temperature becomes equal to or higher than the predetermined change rate, the control of the refrigerant circulation amount is stopped, and the number of times of defrosting is reduced in order to suppress the progress of frost formation on the air heat exchanger 4. be able to.
[0047]
(Example 6)
FIG. 10 is a configuration diagram of a heat pump water heater according to a sixth embodiment of the present invention. FIG. FIG.
[0048]
This embodiment is different from the first embodiment in that an outside air temperature detecting means 11 for detecting an outside air temperature is provided, and when a predetermined condition is satisfied, a temperature difference between the outside air temperature and the evaporation temperature becomes a predetermined value. This is the case when the temperature difference is exceeded. Note that the portions denoted by the same reference numerals as in the first embodiment have the same configuration, and description thereof will be omitted.
[0049]
Next, the operation and operation will be described. The case where the outside air temperature is low and frost formation on the air heat exchanger 4 proceeds will be described with reference to FIG. In the figure, the horizontal axis indicates the operating time, and the vertical axis indicates the temperature difference between the outside air temperature and the evaporating temperature, the valve opening degree of the pressure reducing device 3 and the evaporating temperature of the refrigerant in the air heat exchanger 4, and the operating time. 3 shows changes in the temperature difference between the outside air temperature and the evaporation temperature, and the change in the valve opening of the pressure reducing device 3 and the evaporation temperature. The dotted line in the figure is the case of FIG. 15 described in the conventional example, and the solid line is the case of the present invention. Frost formation advances with the start of operation, and the evaporation temperature decreases. In the case of the conventional example, since the discharge temperature control (or superheat control) of the compressor 1 is performed irrespective of the degree of progress of frost formation, the valve opening of the pressure reducing device 3 becomes smaller as it operates, and The evaporation temperature suddenly drops halfway and reaches the defrost start temperature. At this time, as the frost formation on the air heat exchanger 4 progresses, the evaporation temperature decreases, but on the contrary, the temperature difference between the outside air temperature and the evaporation temperature increases. Therefore, in the case of the present invention, when the temperature difference between the outside air temperature and the evaporation temperature becomes equal to or more than the predetermined temperature difference, the valve opening of the pressure reducing device is kept constant. It becomes smaller than the case. As can be seen from the figure, the time of the hot water supply heating operation before the defrosting operation is started is longer in the case of the present invention than in the conventional example.
[0050]
As described above, when the temperature difference between the outside air temperature and the evaporating temperature becomes equal to or more than the predetermined temperature difference, the control of the amount of circulating refrigerant is stopped, and in order to suppress the progress of frost on the air heat exchanger 4, defrosting is performed. Can be reduced.
[0051]
(Example 7)
FIG. 12 is a configuration diagram of a heat pump water heater according to Embodiment 7 of the present invention, and FIG. 13 is an explanatory diagram showing changes in current value, power consumption value, valve opening degree of a pressure reducing device, and evaporation temperature with respect to operation time of the heat pump water heater. It is.
[0052]
This embodiment is different from the first embodiment in that an electric characteristic value detecting unit 20 for detecting an electric characteristic value of the compressor 1 is provided, and when a predetermined condition is satisfied, the electric characteristic value is set to a predetermined value. In the case where the electric characteristic value becomes equal to or less than the electric characteristic value. The electric characteristic values include a current value and a power consumption value. Note that the portions denoted by the same reference numerals as in the first embodiment have the same configuration, and description thereof will be omitted.
[0053]
Next, the operation and operation will be described. A case where the outside air temperature is low and frost formation on the air heat exchanger 4 proceeds will be described with reference to FIG. In the figure, the horizontal axis indicates the operation time, and the vertical axis indicates the current value, the power consumption, the valve opening degree of the pressure reducing device 3 and the evaporation temperature of the refrigerant in the air heat exchanger 4, and the current value with respect to the operation time. It shows changes in power consumption, a valve opening of the pressure reducing device 3 and an evaporation temperature. The dotted line in the figure is the case of FIG. 15 described in the conventional example, and the solid line is the case of the present invention. Frost formation advances with the start of operation, and the evaporation temperature decreases. In the case of the conventional example, since the discharge temperature control (or superheat control) of the compressor 1 is performed regardless of the degree of progress of frost formation, the valve opening of the pressure reducing device 3 becomes smaller as it operates, and The evaporation temperature suddenly drops halfway and reaches the defrost start temperature. At this time, as the frost formation on the air heat exchanger 4 progresses, the current value and the power consumption value, which are the electrical characteristic values, decrease. Therefore, in the case of the present invention, when the current value is equal to or less than the predetermined current value, or when the power consumption value is equal to or less than the predetermined power consumption value, the valve opening of the pressure reducing device is kept constant. The rate of decrease of the evaporation temperature is smaller than in the case of the conventional dotted line. As can be seen from the figure, the time of the hot water supply heating operation before the defrosting operation is started is longer in the case of the present invention than in the case of the conventional example.
[0054]
As described above, the compressor is provided with the electric characteristic value detecting means 20 for detecting the electric characteristic value of the compressor 1, and when the current value is equal to or less than the predetermined current value, or when the power consumption value is equal to or less than the predetermined power consumption value. In this case, the control of the amount of circulating refrigerant is stopped and the progress of frosting on the air heat exchanger 4 is suppressed, so that the number of times of defrosting can be reduced.
[0055]
In each embodiment, examples of the refrigerant to be used include a chlorofluorocarbon refrigerant such as R410a, a hydrocarbon refrigerant such as propane, and a carbon dioxide refrigerant. When carbon dioxide is used as the refrigerant for the heat pump cycle at a supercritical pressure, it is a substance that does not place a burden on the global environment as compared with the conventional fluorocarbon-based refrigerant.
[0056]
【The invention's effect】
As described above, according to the present invention, the control of the refrigerant circulation amount is stopped when a predetermined condition is satisfied during the frosting operation in which frost forms on the air heat exchanger, so that there is no sharp decrease in the evaporation temperature. In addition, a highly efficient hot water supply heating operation can be performed. In addition, the time for hot water supply heating operation until defrosting can be lengthened, and the number of times of defrosting can be reduced, so that mixing of hot and cold water in the hot water storage tank is reduced, running out of hot water is less likely, and running costs are reduced. There is an effect that can be.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a heat pump water heater according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a change in a valve opening degree and an evaporation temperature of a pressure reducing device with respect to an operation time of the heat pump water heater.
FIG. 3 is a configuration diagram of the heat pump water heater in a case where superheat degree detection means is used as refrigerant circulation amount control means;
FIG. 4 is a configuration diagram of a heat pump water heater according to a second embodiment of the present invention.
FIG. 5 is an explanatory diagram showing changes in the discharge pressure, the valve opening degree of the pressure reducing device, and the evaporation temperature with respect to the operation time of the heat pump water heater.
FIG. 6 is a configuration diagram of a heat pump water heater according to a third embodiment of the present invention.
FIG. 7 is an explanatory diagram showing changes in the discharge temperature, the valve opening degree of the pressure reducing device, and the evaporation temperature with respect to the operation time of the heat pump water heater.
FIG. 8 is an explanatory diagram showing a change in a valve opening degree and an evaporation temperature of a pressure reducing device with respect to an operation time of a heat pump water heater according to a fourth embodiment of the present invention.
FIG. 9 is an explanatory diagram showing a change in a valve opening degree and an evaporation temperature of a pressure reducing device with respect to an operation time of a heat pump water heater according to a fifth embodiment of the present invention.
FIG. 10 is a configuration diagram of a heat pump water heater according to a sixth embodiment of the present invention.
FIG. 11 is an explanatory diagram showing a temperature difference between an outside air temperature and an evaporation temperature, a change in a valve opening of a pressure reducing device, and a change in an evaporation temperature with respect to an operation time of the heat pump water heater.
FIG. 12 is a configuration diagram of a heat pump water heater according to a seventh embodiment of the present invention.
FIG. 13 is an explanatory diagram showing changes in current value, power consumption value, valve opening degree of a pressure reducing device, and evaporation temperature with respect to the operation time of the heat pump water heater.
FIG. 14 is a configuration diagram of a heat pump water heater in a conventional example.
FIG. 15 is an explanatory diagram showing changes in the valve opening degree and the evaporation temperature of the pressure reducing device with respect to the operation time of the heat pump water heater.
[Explanation of symbols]
1 compressor
2 Hot water supply heat exchanger
3 Decompression device
4 Air heat exchanger
5 Hot water storage tank
6 Circulation pump
15 Refrigerant circulation amount control means
16 Frost detection means

Claims

A refrigerant circuit having a compressor, a hot water supply heat exchanger, a pressure reducing device, and an air heat exchanger that absorbs atmospheric heat, a hot water supply circuit having a hot water storage tank, a circulation pump, and the hot water supply heat exchanger, and A refrigerant circulation amount control unit for controlling the refrigerant circulation amount, and a frost detection unit for detecting frost formation on the air heat exchanger, wherein the control of the refrigerant circulation amount is stopped when a predetermined condition is satisfied. Heat pump water heater.

2. The heat pump water heater according to claim 1, wherein a discharge temperature detection means for detecting a discharge temperature of the compressor and a pressure reducing device are used as the refrigerant circulation amount control means.

2. The heat pump water heater according to claim 1, wherein said refrigerant circulation amount control means includes superheat degree detection means for detecting the degree of superheat of refrigerant sucked into said compressor and a pressure reducing device.

The heat pump water heater according to claim 1, wherein the predetermined condition is satisfied when the hot water heating operation time reaches a predetermined time.

2. The heat pump water heater according to claim 1, further comprising discharge pressure detecting means for detecting a discharge pressure, wherein the predetermined condition is satisfied and the discharge pressure is equal to or lower than the predetermined discharge pressure.

2. The heat pump water heater according to claim 1, wherein the predetermined condition is satisfied when the discharge temperature is equal to or lower than the predetermined discharge temperature.

2. The heat pump water heater according to claim 1, wherein the predetermined condition is satisfied when the rate of change of the valve opening of the pressure reducing device is equal to or higher than the predetermined rate of change.

2. The heat pump water heater according to claim 1, further comprising an evaporating temperature detecting means for detecting an evaporating temperature, wherein the predetermined condition is satisfied and the changing speed of the evaporating temperature is equal to or higher than the predetermined changing speed.

Evaporation temperature detection means for detecting the evaporating temperature and outside air temperature detection means for detecting the outside air temperature are provided, and when a predetermined condition is satisfied, when a temperature difference between the outside air temperature and the evaporation temperature becomes equal to or more than a predetermined temperature difference The heat pump water heater according to claim 1, wherein

The heat pump water heater according to claim 1, wherein the predetermined condition is satisfied when the current value is equal to or less than the predetermined current value.

The heat pump water heater according to claim 1, wherein the predetermined condition is satisfied when the power consumption is equal to or less than the predetermined power consumption value.