JP4251785B2

JP4251785B2 - Heat pump water heater

Info

Publication number: JP4251785B2
Application number: JP2001119482A
Authority: JP
Inventors: 丈二黒木; 智明小早川; 和俊草刈; 路之斉川
Original assignee: Central Research Institute of Electric Power Industry; Tokyo Electric Power Co Inc; Denso Corp
Current assignee: Central Research Institute of Electric Power Industry; Tokyo Electric Power Co Inc; Denso Corp
Priority date: 2001-04-18
Filing date: 2001-04-18
Publication date: 2009-04-08
Anticipated expiration: 2021-04-18
Also published as: JP2002318016A

Description

【０００１】
【発明の属する技術分野】
本発明は、超臨界ヒートポンプサイクルを被加熱流体の加熱手段として使用するヒートポンプ式温水器に関する。
【０００２】
【従来の技術】
本出願人による先願技術として、特願２０００−３１１１４２に記載したヒートポンプ式温水器がある。この温水器は、ヒートポンプサイクルに可変式膨張弁（弁開度を調節可能な膨張弁）を具備し、この膨張弁の開度によりサイクル内の高圧圧力を制御している。具体的には、利用水と冷媒とを熱交換させる水熱交換器の入口側給水温度と出口側冷媒温度との温度差が予め設定された目標温度差ΔＴとなる様に、膨張弁の開度を調節して高圧制御を行っている。
【０００３】
【発明が解決しようとする課題】
ところが、先願の膨張弁制御では、温水器が置かれる環境条件（外気温度、給水温度）に係わらず、膨張弁の初期開度が一律一定（３００Step）に設定されており、給湯運転が開始されてから、徐々に目標温度差ΔＴまで安定する様に動作している。このため、膨張弁の目標開度に到達するまでの動作時間が外的条件によって異なり、例えば夏季（目標開度２５０Step）より冬期（目標開度１００Step）の方が、目標開度に到達するまでの膨張弁の動作時間が長くなってしまう。
【０００４】
この結果、給湯運転の立ち上がりで目標能力到達時間、及び目標出湯温度到達時間の遅れが生じ、温水器の沸き上げ時間が遅れるという問題があった。
本発明は、上記事情に基づいて成されたもので、膨張弁の動作が安定するまでの時間（目標開度に到達するまでの時間）を短縮することにより、温水器の沸き上げ時間の遅れを低減することにある。
【０００７】
【課題を解決するための手段】
（請求項１の手段）
制御装置は、圧縮機を起動する前に、予め膨張弁を一定の初期開度まで動作させ、圧縮機を起動した後、初期開度から中間開度まで第１の動作速度で膨張弁の開度を制御し、中間開度に到達した後、目標開度まで第１の動作速度より小さい第２の動作速度で膨張弁の開度を制御する。中間開度は、外気温度と給水温度の少なくとも一方の温度から求められる給湯運転安定時の目標開度と初期開度との間に設定される。
【０００８】
この発明によれば、初期開度から中間開度まで第２の動作速度より速い第１の動作速度で膨張弁の開度を制御できるので、従来の膨張弁制御（初期開度から目標開度に安定するまで膨張弁の開度を徐々に制御している）と比較して、膨張弁が目標開度に安定するまでの動作時間を短縮できる。その結果、温水器の沸き上げ時間を短縮できる。また、給湯運転時間（圧縮機等の稼働時間）の短縮による消費電力の低減、及びシステム機能品の耐久性向上を図ることができる。
【００１１】
（請求項２の手段）
制御装置は、圧縮機を起動する前に、予め膨張弁を一定の初期開度まで動作させ、前日の給湯運転安定時の膨張弁開度を基に今回の給湯運転安定時の膨張弁目標開度を予測し、その目標開度と初期開度との間に中間開度を設定し、圧縮機を起動した後、初期開度から中間開度まで第１の動作速度で膨張弁の開度を制御し、中間開度に到達した後、目標開度まで第１の動作速度より小さい第２の動作速度で膨張弁の開度を制御する。
【００１２】
この発明によれば、初期開度から中間開度まで第２の動作速度より速い第１の動作速度で膨張弁の開度を制御できるので、従来の膨張弁制御（初期開度から目標開度に安定するまで膨張弁の開度を徐々に制御している）と比較して、膨張弁が目標開度に安定するまでの動作時間を短縮できる。その結果、温水器の沸き上げ時間を短縮できる。また、給湯運転時間（圧縮機等の稼働時間）の短縮による消費電力の低減、及びシステム機能品の耐久性向上を図ることができる。
【００１３】
（請求項３の手段）
請求項２に記載したヒートポンプ式温水器において、
制御装置は、給湯運転安定時の膨張弁開度を記憶する記憶回路を有し、この記憶回路は、運転毎に給湯運転安定時の膨張弁開度を更新する。これにより、今回の給湯運転安定時の膨張弁開度を基に次回の給湯運転安定時の膨張弁開度を目標開度として予測することができる。
【００１４】
（請求項４の手段）
請求項１〜３に記載した何れかのヒートポンプ式温水器において、
外気温度が高くなる程、膨張弁の目標開度が大きく設定される。
【００１５】
（請求項５の手段）
請求項１〜３に記載した何れかのヒートポンプ式温水器において、
給水温度が高くなる程、膨張弁の目標開度が大きく設定される。
【００１６】
（請求項６の手段）
請求項１〜５に記載した何れかのヒートポンプ式温水器において、
水熱交換器に流入する利用水と水熱交換器から流出する冷媒との温度差が目標温度差ΔＴとなるように、膨張弁の開度を調節してサイクル内の高圧を制御している。例えば、膨張弁の開度を小さくすると、冷媒の流路抵抗が大きくなるので、圧縮機から吐出される高圧側の冷媒圧力が上昇する。逆に、膨張弁の開度を大きくすると、冷媒の流路抵抗が小さくなるので、圧縮機から吐出される高圧側の冷媒圧力が低下する。即ち、目標温度差ΔＴが得られる様に、膨張弁の開度を調節してサイクル内の高圧を制御している。
【００１７】
（請求項７の手段）
請求項１〜６に記載した何れかのヒートポンプ式温水器において、
ヒートポンプサイクルの冷媒としてＣＯ_２を使用した場合、ＣＯ_２の臨界圧力が低いため、高圧側の冷媒圧力を臨界圧以上まで加圧できる。これにより、高い給湯温度（例えば９０℃）を達成することが可能である。
【００１８】
【発明の実施の形態】
次に、本発明のヒートポンプ式温水器を図面に基づいて説明する。
図１はヒートポンプ式温水器１のシステム構成図である。
ヒートポンプ式温水器１は、図１に示す様に、加熱された利用水をタンク２内に貯留しておき、使用時にタンク２内から取り出した利用水を温度調節して使用者に供給する給湯システムに用いられるもので、利用水の加熱手段であるヒートポンプサイクル（後述する）と、給湯システム全体の作動を制御する制御装置３を具備している。
【００１９】
タンク２は、耐蝕性に優れた金属製（例えばステンレス製）で断熱構造を有し、高温の利用水を長時間に渡って保温することができる。なお、タンク２内に貯留される利用水は、キッチンや風呂等で直接使用しても良いが、給湯用以外に、例えば床暖房用、室内空調用等の熱源として利用することもできる。
このタンク２は、水側配管４を介して下述する水熱交換器５の給水通路に接続されている。水側配管４は、一端がタンク２の下部に設けられる出口ポート２ａに接続され、他端がタンク２の上部に設けられる入口ポート２ｂに接続されている。
【００２０】
また、水側配管４には、タンク２と水熱交換器５との間で利用水を循環させる電動ポンプ６が設けられている。この電動ポンプ６は、内蔵するモータの回転数に応じて循環水量を調節することができる。
ヒートポンプサイクルは、臨界圧力の低い二酸化炭素（ＣＯ₂）を冷媒として使用することにより、高圧側の冷媒圧力が臨界圧力以上まで加圧される。
このヒートポンプサイクルは、図１に示すように、圧縮機７、水熱交換器５、膨張弁８、空気熱交換器９、アキュムレータ１０等によって構成される。
【００２１】
圧縮機７は、インバータ回路１１によって駆動されるモータを内蔵し、このモータの回転により、吸引したガス冷媒を臨界圧力以上まで圧縮して吐出する。
水熱交換器５は、圧縮機７より吐出された高圧のガス冷媒と利用水とを熱交換するもので、図１に矢印で示すように、冷媒の流れ方向と利用水の流れ方向とが対向している。
【００２２】
膨張弁８は、弁開度を調節可能な構成を有し、水熱交換器５で冷却された冷媒を弁開度に応じて減圧する。この膨張弁８の制御方法について後述する。
空気熱交換器９は、ファン１２による送風を受けて、膨張弁８で減圧された冷媒を外気との熱交換によって蒸発させる。
アキュムレータ１０は、空気熱交換器９で蒸発した冷媒を気液分離してサイクル中の余剰冷媒を蓄えるとともに、気相冷媒のみ圧縮機７に吸引させる。
【００２３】
この給湯システムには、図１に示す様に、水熱交換器５に流入する利用水の温度Twを検出する水温センサ１３、水熱交換器５より流出する冷媒の温度Trを検出する冷媒温度センサ１４、及び外気温度Tam を検出する外気温センサ１５等が具備され、各センサ１３〜１５で検出された情報（センサ信号）が制御装置３に出力される。
【００２４】
制御装置３は、ヒートポンプサイクルを効率良く運転できるように、水熱交換器５に流入する利用水と水熱交換器５より流出する冷媒との温度差を求め、この温度差に基づいてサイクル内の高圧側圧力を制御している。具体的には、最高のサイクル効率付近で運転できる最適温度差（目標温度差ΔＴと呼ぶ）を求め、この目標温度差ΔＴ（例えば１０℃）が得られるように、膨張弁８の開度を電気的に制御している（図２参照）。
【００２５】
次に、給湯運転を制御する制御装置３の処理手順を図３に示すフローチャートに基づいて説明する。
Step10…起動スイッチがＯＮされて制御装置３が起動する。
Step20…膨張弁８のイニシャル処理（後述する）を実行する。
Step30…システムを起動する。ここでは、圧縮機７、ファン１２、電動ポンプ６等を起動させる。
Step40…給湯運転を開始する。
【００２６】
この給湯運転の動作を簡単に説明する。
ヒートポンプサイクルでは、圧縮機７で高温・高圧に圧縮された冷媒が水熱交換器５に供給され、水熱交換器５で放熱して温度低下した後、膨張弁８で減圧される。減圧された冷媒は、空気熱交換器９へ送られ、空気熱交換器９で外気から吸熱して蒸発し、アキュムレータ１０で気液分離された後、ガス冷媒のみが圧縮機７に吸引される。
一方、タンク２内の利用水は、電動ポンプ６によって出口ポート２ａから水側配管４を通って水熱交換器５へ送られ、水熱交換器５で高温冷媒との熱交換により加熱された後、水側配管４を通って入口ポート２ｂから再びタンク２内に流入して貯留される。
【００２７】
（第１実施例）
次に、膨張弁８のイニシャル処理（Step20）について説明する。
Step21…外気温度と給水温度を読み込む。この場合、制御装置３に内蔵される記憶回路から前回運転時の外気温度と給水温度を読み出して使用しても良い。
Step22…膨張弁８の初期開度を演算する。この初期開度は、ΔＴ≒１０℃で給湯運転が安定する時の膨張弁８の目標開度であり、外気温度と給水温度に応じて、例えば、図４に示すマップから、あるいは制御装置３が有する演算回路にて演算される。
Step23…膨張弁８を初期開度まで動作させる。
【００２８】
本実施例では、システムを起動する前に膨張弁８のイニシャル処理を行うことにより、給湯運転を開始する時点で、既に膨張弁８が目標開度（初期開度）に設定されている。これにより、季節毎に膨張弁８の目標開度が異なる場合でも、その時の外気温度及び給水温度に応じた目標開度に設定することができる。この結果、従来の膨張弁制御（膨張弁８が一律一定の初期開度から動作する）と比較すると、圧縮機７を起動してから膨張弁８の動作が安定する（ΔＴ≒１０℃で給湯運転が安定する）までの時間を大幅に短縮でき、温水器１の沸き上げ時間を短縮できる。
【００２９】
また、目標給湯能力が得られるまでの給湯運転時間（圧縮機７等の稼働時間）を短縮できるので、消費電力の低減、及びシステム機能品の耐久性向上を図ることができる。
なお、本実施例では、外気温度と給水温度に応じて膨張弁８の目標開度を求めているが、外気温度と給水温度の何方か一方の温度だけをパラメータとして膨張弁８の目標開度を求めても良い。
【００３０】
（第２実施例）
本実施例は、膨張弁８のイニシャル処理に係わる第２実施例であり、膨張弁８が目標開度に安定するまでの動作速度を二段階に制御する一例である。
制御装置３は、膨張弁８の初期開度、中間開度、及び目標開度を設定し、初期開度から中間開度までを第１の動作速度で制御し、中間開度から目標開度までを第２の動作速度で制御する。なお、中間開度は、初期開度（給湯運転が安定する膨張弁８の目標開度とは異なる）と目標開度との間に設定される。また、目標開度は、第１実施例と同様に、外気温度及び給水温度に応じてマップ（図４参照）から、あるいは演算回路にて演算される。
【００３１】
以下に、本実施例の作動を具体的に説明する。
システムを起動する前に、予め膨張弁８を一定の初期開度まで動作させる。
次に、システムを起動して給湯運転を開始する。
この給湯運転では、図５に示す様に、初期開度から中間開度まで第１の動作速度（図中Ａの特性）で膨張弁８の開度を制御し、中間開度に到達した後、目標開度まで第２の動作速度（但し、第１の動作速度＞第２の動作速度：図中Ｂの特性）で膨張弁８の開度を制御する。
【００３２】
本実施例によれば、初期開度から中間開度まで第２の動作速度より速い第１の動作速度で膨張弁８の開度を制御できるので、従来の制御弁制御（初期開度から目標開度に安定するまで膨張弁８の開度を徐々に制御している）と比較して、膨張弁８が目標開度に安定するまでの動作時間を短縮できる。その結果、目標給湯能力が得られるまでの給湯運転時間（圧縮機７等の稼働時間）を短縮できるので、消費電力の低減、及びシステム機能品の耐久性向上を図ることができる。
【００３３】
（第３実施例）
本実施例は、膨張弁８のイニシャル処理に係わる第３実施例である。
第１実施例では、外気温度と給水温度に応じて膨張弁８の初期開度（目標開度）を求めているが、本実施例は、前日の給湯運転安定時の膨張弁開度を基に今回の給湯運転安定時の制御弁目標開度を予測し、その目標開度を膨張弁８の初期開度として設定する一例である。
【００３４】
以下に、膨張弁８のイニシャル処理に係わる制御装置３の処理手順を図６に示すフローチャートに基づいて説明する。
Step210 …起動スイッチがＯＮされた後、記憶回路から前日の給湯運転安定時の膨張弁開度を取り出す。
Step220 …外気温度及び給水温度を検出する。この外気温度及び給水温度は、前日に検出された値でも良い。
【００３５】
Step230 …外気温度または給水温度に応じて、記憶回路から取り出した前日の給湯運転安定時の膨張弁開度を基に、今回の膨張弁開度を演算する。この膨張弁開度は、ΔＴ≒１０℃で給湯運転が安定する時の膨張弁８の目標開度であり、外気温度または給水温度に応じて、例えば、図７に示すマップから演算される。
Step240 …膨張弁８を目標開度（初期開度）まで動作させる。
なお、記憶回路に記憶されている前回の給湯運転安定時の膨張弁開度は、今回の給湯運転安定時の膨張弁開度によって更新される。
【００３６】
本実施例においても、第１実施例と同様に、給湯運転を開始する時点で、既に膨張弁８が目標開度（初期開度）に設定されているので、従来の制御弁制御と比較して、圧縮機７を起動してから膨張弁８の動作が安定する（ΔＴ≒１０℃で給湯運転が安定する）までの時間を大幅に短縮でき、温水器１の沸き上げ時間を短縮できる。また、目標給湯能力が得られるまでの給湯運転時間（圧縮機７等の稼働時間）を短縮できるので、消費電力の低減、及びシステム機能品の耐久性向上を図ることもできる。
【００３７】
（第４実施例）
本実施例は、膨張弁８のイニシャル処理に係わる第４実施例であり、上述した第２実施例と同様に、膨張弁８が目標開度に安定するまでの動作速度を二段階に制御する一例である。
第２実施例と異なる点は、膨張弁８の目標開度を前日の給湯運転安定時の膨張弁開度を基に予測することである。即ち、第３実施例と同様に、記憶回路から前日の給湯運転安定時の膨張弁開度を取り出し、外気温度または給水温度に応じて今回の膨張弁開度（目標開度）を演算する。この場合、図７に示したマップから求めることができる。
【００３８】
その後、第２実施例と同様に、予め膨張弁８を一定の初期開度まで動作させてからシステムを起動して給湯運転を開始する。この給湯運転では、初期開度から中間開度まで第１の動作速度（図５参照）で膨張弁８の開度を制御し、中間開度に到達した後、上記の様に前日の給湯運転安定時の膨張弁開度を基に予測した目標開度まで第２の動作速度（第１の動作速度＞第２の動作速度：図５参照）で膨張弁８の開度を制御する。
【００３９】
本実施例においても、第２実施例と同様に、初期開度から中間開度まで第２の動作速度より速い第１の動作速度で膨張弁８の開度を制御できるので、従来の制御弁制御と比較して、膨張弁８が目標開度に安定するまでの動作時間を短縮できる。その結果、目標給湯能力が得られるまでの給湯運転時間（圧縮機７等の稼働時間）を短縮できるので、消費電力の低減、及びシステム機能品の耐久性向上を図ることができる。
【図面の簡単な説明】
【図１】ヒートポンプ式温水器のシステム構成図である。
【図２】制御弁制御の一例を示す説明図である。
【図３】制御装置の処理手順を示すフローチャートである（第１実施例）。
【図４】膨張弁の初期開度を求めるマップである。
【図５】膨張弁の制御方法を示す動作マップである（第２、４実施例）。
【図６】制御装置の処理手順を示すフローチャートである（第３実施例）。
【図７】膨張弁の目標開度を求めるマップである（第３、４実施例）。
【符号の説明】
１ヒートポンプ式温水器
３制御装置
５水熱交換器
７圧縮機
８膨張弁[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat pump water heater that uses a supercritical heat pump cycle as means for heating a fluid to be heated.
[0002]
[Prior art]
As a prior application technique by the present applicant, there is a heat pump water heater described in Japanese Patent Application No. 2000-311142. This water heater has a variable expansion valve (an expansion valve whose valve opening degree can be adjusted) in a heat pump cycle, and the high pressure in the cycle is controlled by the opening degree of the expansion valve. Specifically, the expansion valve is opened so that the temperature difference between the inlet-side water supply temperature and the outlet-side refrigerant temperature of the water heat exchanger that exchanges heat between the use water and the refrigerant becomes a preset target temperature difference ΔT. High pressure control is performed by adjusting the degree.
[0003]
[Problems to be solved by the invention]
However, in the expansion valve control of the prior application, the initial opening of the expansion valve is set to be uniform (300 Step) regardless of the environmental conditions (outside air temperature, feed water temperature) where the water heater is placed, and the hot water supply operation is started. After being operated, the operation is performed so as to be gradually stabilized up to the target temperature difference ΔT. For this reason, the operation time until reaching the target opening of the expansion valve varies depending on external conditions. For example, in winter (target opening 100 Step) than in summer (target opening 250 Step), the target opening is reached. The operation time of the expansion valve becomes longer.
[0004]
As a result, there has been a problem that the target capacity reaching time and the target hot water temperature reaching time are delayed at the start of the hot water supply operation, and the boiling time of the water heater is delayed.
The present invention has been made based on the above circumstances, and by delaying the time until the operation of the expansion valve is stabilized (the time until the target opening is reached), the heating time of the water heater is delayed. It is to reduce.
[0007]
[Means for Solving the Problems]
(Means of Claim 1 )
Before starting the compressor, the control device operates the expansion valve to a certain initial opening degree in advance, and after starting the compressor, opens the expansion valve at the first operating speed from the initial opening degree to the intermediate opening degree. After the intermediate opening is reached, the opening of the expansion valve is controlled at a second operating speed lower than the first operating speed until the target opening. The intermediate opening is set between the target opening and the initial opening when the hot water supply operation is stable, which is obtained from at least one of the outside air temperature and the feed water temperature.
[0008]
According to the present invention, since the opening degree of the expansion valve can be controlled from the initial opening degree to the intermediate opening degree at the first operating speed that is faster than the second operating speed, conventional expansion valve control (from the initial opening degree to the target opening degree) is possible. The operation time until the expansion valve is stabilized at the target opening can be shortened as compared to the case where the expansion valve is gradually controlled until the expansion valve is stabilized. As a result, the boiling time of the water heater can be shortened. In addition, the power consumption can be reduced by shortening the hot water supply operation time (operating time of the compressor, etc.), and the durability of the system function product can be improved.
[0011]
(Means of Claim 2 )
Before starting the compressor, the control device operates the expansion valve in advance to a certain initial opening, and based on the expansion valve opening when the hot water supply operation is stable on the previous day, the expansion valve target opening when the hot water supply operation is stable this time. The degree of opening is set, an intermediate opening is set between the target opening and the initial opening, the compressor is started, and then the expansion valve opening at the first operating speed from the initial opening to the intermediate opening. After the intermediate opening is reached, the opening of the expansion valve is controlled at a second operating speed smaller than the first operating speed until the target opening.
[0012]
According to the present invention, since the opening degree of the expansion valve can be controlled from the initial opening degree to the intermediate opening degree at the first operating speed that is faster than the second operating speed, conventional expansion valve control (from the initial opening degree to the target opening degree) is possible. The operation time until the expansion valve is stabilized at the target opening can be shortened as compared to the case where the expansion valve is gradually controlled until the expansion valve is stabilized. As a result, the boiling time of the water heater can be shortened. In addition, the power consumption can be reduced by shortening the hot water supply operation time (operating time of the compressor, etc.), and the durability of the system function product can be improved.
[0013]
(Means of claim 3 )
In the heat pump type water heater according to claim 2 ,
The control device includes a storage circuit that stores an expansion valve opening when the hot water supply operation is stable, and the storage circuit updates the expansion valve opening when the hot water supply operation is stable for each operation. Thereby, the expansion valve opening degree at the time of the next stable hot water supply operation can be predicted as the target opening degree based on the expansion valve opening degree at the time of the stable hot water supply operation.
[0014]
(Means of claim 4 )
In the heat pump type water heater according to any one of claims 1 to 3 ,
The target opening degree of the expansion valve is set larger as the outside air temperature becomes higher.
[0015]
(Means of claim 5 )
In the heat pump type water heater according to any one of claims 1 to 3 ,
The target opening degree of the expansion valve is set larger as the feed water temperature becomes higher.
[0016]
(Means of claim 6 )
In any one of the heat pump type water heaters according to claims 1 to 5 ,
The high pressure in the cycle is controlled by adjusting the opening of the expansion valve so that the temperature difference between the water flowing into the water heat exchanger and the refrigerant flowing out of the water heat exchanger becomes the target temperature difference ΔT. . For example, when the opening degree of the expansion valve is reduced, the flow path resistance of the refrigerant increases, so that the refrigerant pressure on the high pressure side discharged from the compressor increases. On the contrary, if the opening degree of the expansion valve is increased, the flow path resistance of the refrigerant is decreased, so that the refrigerant pressure on the high pressure side discharged from the compressor is decreased. That is, the high pressure in the cycle is controlled by adjusting the opening of the expansion valve so that the target temperature difference ΔT is obtained.
[0017]
(Means of claim 7 )
In any one of heat-pump type water heaters described in Claims 1-6 ,
When CO ₂ is used as the refrigerant in the heat pump cycle, the critical pressure of CO ₂ is low, so that the refrigerant pressure on the high pressure side can be increased to the critical pressure or higher. Thereby, it is possible to achieve a high hot water supply temperature (for example, 90 ° C.).
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, the heat pump type water heater of this invention is demonstrated based on drawing.
FIG. 1 is a system configuration diagram of a heat pump water heater 1.
As shown in FIG. 1, the heat pump water heater 1 stores heated use water in a tank 2, adjusts the temperature of the use water taken out from the tank 2 during use, and supplies it to a user. It is used in the system, and includes a heat pump cycle (described later) that is a heating means for use water and a control device 3 that controls the operation of the entire hot water supply system.
[0019]
The tank 2 is made of metal (for example, made of stainless steel) excellent in corrosion resistance and has a heat insulating structure, and can keep hot water for a long time. In addition, although the utilization water stored in the tank 2 may be used directly in a kitchen, a bath, etc., it can also be utilized as a heat source for floor heating, indoor air conditioning, etc. other than for hot water supply.
The tank 2 is connected to a water supply passage of a water heat exchanger 5 described below via a water side pipe 4. One end of the water side pipe 4 is connected to an outlet port 2 a provided in the lower part of the tank 2, and the other end is connected to an inlet port 2 b provided in the upper part of the tank 2.
[0020]
The water side pipe 4 is provided with an electric pump 6 that circulates the used water between the tank 2 and the water heat exchanger 5. The electric pump 6 can adjust the amount of circulating water according to the number of rotations of a built-in motor.
In the heat pump cycle, carbon dioxide (CO ₂ ) having a low critical pressure is used as a refrigerant, so that the refrigerant pressure on the high pressure side is increased to a critical pressure or higher.
As shown in FIG. 1, this heat pump cycle includes a compressor 7, a water heat exchanger 5, an expansion valve 8, an air heat exchanger 9, an accumulator 10, and the like.
[0021]
The compressor 7 incorporates a motor driven by the inverter circuit 11, and compresses and discharges the sucked gas refrigerant to a critical pressure or higher by rotation of the motor.
The water heat exchanger 5 exchanges heat between the high-pressure gas refrigerant discharged from the compressor 7 and the used water. As shown by arrows in FIG. 1, the flow direction of the refrigerant and the flow direction of the used water are determined. Opposite.
[0022]
The expansion valve 8 has a configuration in which the valve opening degree can be adjusted, and decompresses the refrigerant cooled by the water heat exchanger 5 according to the valve opening degree. A method for controlling the expansion valve 8 will be described later.
The air heat exchanger 9 receives air blown by the fan 12 and evaporates the refrigerant decompressed by the expansion valve 8 by heat exchange with the outside air.
The accumulator 10 gas-liquid separates the refrigerant evaporated in the air heat exchanger 9 to store surplus refrigerant in the cycle, and causes the compressor 7 to suck only the gas-phase refrigerant.
[0023]
In this hot water supply system, as shown in FIG. 1, a water temperature sensor 13 for detecting the temperature Tw of the used water flowing into the water heat exchanger 5 and a refrigerant temperature for detecting the temperature Tr of the refrigerant flowing out of the water heat exchanger 5 are used. A sensor 14 and an outside air temperature sensor 15 that detects the outside air temperature Tam are provided, and information (sensor signals) detected by the sensors 13 to 15 is output to the control device 3.
[0024]
The control device 3 obtains a temperature difference between the use water flowing into the water heat exchanger 5 and the refrigerant flowing out of the water heat exchanger 5 so that the heat pump cycle can be efficiently operated, and the inside of the cycle is determined based on this temperature difference. The high pressure side pressure is controlled. Specifically, an optimum temperature difference (referred to as a target temperature difference ΔT) that can be operated in the vicinity of the maximum cycle efficiency is obtained, and the opening degree of the expansion valve 8 is set so as to obtain this target temperature difference ΔT (for example, 10 ° C.). It is electrically controlled (see FIG. 2).
[0025]
Next, the processing procedure of the control device 3 for controlling the hot water supply operation will be described based on the flowchart shown in FIG.
Step 10 ... The start switch is turned on and the control device 3 is started.
Step 20 ... The initial process (described later) of the expansion valve 8 is executed.
Step30 ... Start the system. Here, the compressor 7, the fan 12, the electric pump 6 and the like are started.
Step40 ... Start hot water supply operation.
[0026]
The operation of this hot water supply operation will be briefly described.
In the heat pump cycle, the refrigerant compressed to a high temperature and a high pressure by the compressor 7 is supplied to the water heat exchanger 5, radiates heat by the water heat exchanger 5, drops in temperature, and then decompressed by the expansion valve 8. The decompressed refrigerant is sent to the air heat exchanger 9 and absorbs heat from the outside air by the air heat exchanger 9 to evaporate. After being separated into gas and liquid by the accumulator 10, only the gas refrigerant is sucked into the compressor 7. .
On the other hand, the water used in the tank 2 is sent from the outlet port 2a through the water-side pipe 4 to the water heat exchanger 5 by the electric pump 6 and heated by heat exchange with the high-temperature refrigerant in the water heat exchanger 5. Thereafter, the water flows into the tank 2 again from the inlet port 2b through the water-side pipe 4 and is stored.
[0027]
(First embodiment)
Next, the initial process (Step 20) of the expansion valve 8 will be described.
Step21… Read the outside air temperature and feed water temperature. In this case, the outside air temperature and the water supply temperature at the previous operation may be read from the memory circuit built in the control device 3 and used.
Step 22 ... The initial opening of the expansion valve 8 is calculated. This initial opening is the target opening of the expansion valve 8 when the hot water supply operation is stabilized at ΔT≈10 ° C., and, for example, from the map shown in FIG. 4 or the control device 3 according to the outside air temperature and the water supply temperature. Is calculated by an arithmetic circuit included in.
Step 23 ... Operate the expansion valve 8 to the initial opening.
[0028]
In this embodiment, the expansion valve 8 is already set to the target opening (initial opening) at the time of starting the hot water supply operation by performing the initial process of the expansion valve 8 before starting the system. Thereby, even when the target opening degree of the expansion valve 8 differs every season, it can be set to the target opening degree according to the outside air temperature and the feed water temperature at that time. As a result, compared with the conventional expansion valve control (the expansion valve 8 operates from a uniform initial opening), the operation of the expansion valve 8 becomes stable after the compressor 7 is started (hot water supply at ΔT≈10 ° C.). Time until the operation is stabilized) and the boiling time of the water heater 1 can be shortened.
[0029]
Moreover, since the hot water supply operation time (operating time of the compressor 7 etc.) until the target hot water supply capacity is obtained can be shortened, it is possible to reduce power consumption and improve the durability of system function products.
In this embodiment, the target opening degree of the expansion valve 8 is obtained according to the outside air temperature and the feed water temperature, but the target opening degree of the expansion valve 8 is set using only one of the outside air temperature and the feed water temperature as a parameter. You may ask for.
[0030]
(Second embodiment)
The present embodiment is a second embodiment related to the initial process of the expansion valve 8, and is an example of controlling the operation speed until the expansion valve 8 is stabilized at the target opening degree in two stages.
The control device 3 sets the initial opening, the intermediate opening, and the target opening of the expansion valve 8, controls the initial opening to the intermediate opening at the first operating speed, and controls the intermediate opening to the target opening. Are controlled at the second operation speed. The intermediate opening is set between the initial opening (different from the target opening of the expansion valve 8 where the hot water supply operation is stable) and the target opening. In addition, the target opening is calculated from a map (see FIG. 4) or by an arithmetic circuit according to the outside air temperature and the feed water temperature, as in the first embodiment.
[0031]
The operation of this embodiment will be specifically described below.
Before starting the system, the expansion valve 8 is operated to a certain initial opening degree in advance.
Next, the system is activated to start the hot water supply operation.
In this hot water supply operation, as shown in FIG. 5, after the opening degree of the expansion valve 8 is controlled at the first operating speed (characteristic A in the figure) from the initial opening degree to the intermediate opening degree, The opening degree of the expansion valve 8 is controlled at the second operating speed (where the first operating speed> the second operating speed: the characteristic B in the figure) up to the target opening degree.
[0032]
According to the present embodiment, since the opening degree of the expansion valve 8 can be controlled from the initial opening degree to the intermediate opening degree at the first operating speed that is faster than the second operating speed, the conventional control valve control (from the initial opening degree to the target opening degree) is possible. The operation time until the expansion valve 8 is stabilized at the target opening can be shortened compared to the case where the opening of the expansion valve 8 is gradually controlled until the opening is stabilized. As a result, since the hot water supply operation time (operation time of the compressor 7 or the like) until the target hot water supply capacity is obtained can be shortened, the power consumption can be reduced and the durability of the system function product can be improved.
[0033]
(Third embodiment)
This embodiment is a third embodiment related to the initial process of the expansion valve 8.
In the first embodiment, the initial opening degree (target opening degree) of the expansion valve 8 is obtained according to the outside air temperature and the feed water temperature, but this embodiment is based on the expansion valve opening degree when the hot water supply operation is stabilized on the previous day. 3 is an example in which the target opening of the control valve is predicted when the hot water supply operation is stabilized, and the target opening is set as the initial opening of the expansion valve 8.
[0034]
Below, the process sequence of the control apparatus 3 regarding the initial process of the expansion valve 8 is demonstrated based on the flowchart shown in FIG.
Step 210 ... After the start switch is turned on, the opening degree of the expansion valve when the hot water supply operation of the previous day is stable is taken out from the memory circuit.
Step220 ... Detects the outside air temperature and feed water temperature. The outside air temperature and the water supply temperature may be values detected on the previous day.
[0035]
Step 230 ... The current expansion valve opening is calculated based on the expansion valve opening when the hot water supply operation on the previous day is taken out of the storage circuit according to the outside air temperature or the feed water temperature. This expansion valve opening is the target opening of the expansion valve 8 when the hot water supply operation is stabilized at ΔT≈10 ° C., and is calculated from, for example, a map shown in FIG. 7 according to the outside air temperature or the water supply temperature.
Step 240 ... Operate the expansion valve 8 to the target opening (initial opening).
The previous expansion valve opening degree when the hot water supply operation is stable, which is stored in the storage circuit, is updated by the expansion valve opening degree when the hot water supply operation is stable this time.
[0036]
Also in the present embodiment, as in the first embodiment, the expansion valve 8 is already set to the target opening (initial opening) at the time of starting the hot water supply operation, so compared with the conventional control valve control. Thus, the time from when the compressor 7 is started to when the operation of the expansion valve 8 is stabilized (ΔT≈10 ° C. and the hot water supply operation is stabilized) can be greatly shortened, and the boiling time of the water heater 1 can be shortened. Moreover, since the hot water supply operation time (operating time of the compressor 7 etc.) until the target hot water supply capacity is obtained can be shortened, the power consumption can be reduced and the durability of the system function product can be improved.
[0037]
(Fourth embodiment)
The present embodiment is a fourth embodiment related to the initial process of the expansion valve 8, and controls the operation speed until the expansion valve 8 is stabilized at the target opening degree in two steps, as in the second embodiment described above. It is an example.
The difference from the second embodiment is that the target opening degree of the expansion valve 8 is predicted based on the opening degree of the expansion valve when the hot water supply operation is stabilized on the previous day. That is, as in the third embodiment, the expansion valve opening when the hot water supply operation on the previous day is stable is extracted from the storage circuit, and the current expansion valve opening (target opening) is calculated according to the outside air temperature or the water supply temperature. In this case, it can be obtained from the map shown in FIG.
[0038]
Thereafter, similarly to the second embodiment, the expansion valve 8 is operated in advance to a certain initial opening degree, and then the system is started to start the hot water supply operation. In this hot water supply operation, the opening degree of the expansion valve 8 is controlled at the first operation speed (see FIG. 5) from the initial opening degree to the intermediate opening degree, and after reaching the intermediate opening degree, the hot water supply operation on the previous day is performed as described above. The opening degree of the expansion valve 8 is controlled at the second operating speed (first operating speed> second operating speed: see FIG. 5) up to the target opening degree that is predicted based on the stable opening degree of the expansion valve.
[0039]
Also in this embodiment, since the opening degree of the expansion valve 8 can be controlled at the first operating speed faster than the second operating speed from the initial opening degree to the intermediate opening degree as in the second embodiment, the conventional control valve Compared with the control, the operation time until the expansion valve 8 is stabilized at the target opening can be shortened. As a result, since the hot water supply operation time (operation time of the compressor 7 or the like) until the target hot water supply capacity is obtained can be shortened, the power consumption can be reduced and the durability of the system function product can be improved.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of a heat pump water heater.
FIG. 2 is an explanatory diagram showing an example of control valve control.
FIG. 3 is a flowchart showing a processing procedure of the control device (first embodiment).
FIG. 4 is a map for obtaining an initial opening degree of an expansion valve.
FIG. 5 is an operation map showing an expansion valve control method (second and fourth embodiments).
FIG. 6 is a flowchart showing a processing procedure of a control device (third embodiment).
FIG. 7 is a map for obtaining a target opening of an expansion valve (third and fourth embodiments).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heat pump type water heater 3 Control device 5 Water heat exchanger 7 Compressor 8 Expansion valve

Claims

吸入した冷媒を圧縮して吐出する圧縮機と、
この圧縮機で加圧された冷媒と利用水とを熱交換する水熱交換器と、
この水熱交換器より下流の冷媒通路に設けられ、開度を調節可能な膨張弁と、
前記圧縮機を起動する前に、前記膨張弁を予め一定の初期開度まで動作させた後、前記圧縮機を起動して給湯運転を開始する制御装置とを備え、
この制御装置は、外気温度と給水温度の少なくとも一方の温度から求められる給湯運転安定時の目標開度と前記初期開度との間に中間開度を設定し、前記圧縮機を起動した後、前記初期開度から前記中間開度まで第１の動作速度で前記膨張弁の開度を制御し、前記中間開度に到達した後、前記目標開度まで前記第１の動作速度より小さい第２の動作速度で前記膨張弁の開度を制御することを特徴とするヒートポンプ式温水器。A compressor for compressing and discharging the sucked refrigerant;
A water heat exchanger for exchanging heat between the refrigerant pressurized by the compressor and the water used;
An expansion valve that is provided in the refrigerant passage downstream from the water heat exchanger and that can adjust the opening;
Before starting the compressor, after operating the expansion valve to a predetermined initial opening in advance , and a controller for starting the hot water supply operation by starting the compressor,
This control device sets an intermediate opening between the target opening and the initial opening at the time of stable hot water operation obtained from at least one of the outside air temperature and the feed water temperature, and after starting the compressor, The opening degree of the expansion valve is controlled at a first operating speed from the initial opening degree to the intermediate opening degree, and after reaching the intermediate opening degree, a second smaller than the first operating speed until the target opening degree is reached. The heat pump type water heater is characterized in that the opening degree of the expansion valve is controlled at the operation speed of the heat pump.

吸入した冷媒を圧縮して吐出する圧縮機と、
この圧縮機で加圧された冷媒と利用水とを熱交換する水熱交換器と、
この水熱交換器より下流の冷媒通路に設けられ、開度を調節可能な膨張弁と、
前記圧縮機を起動する前に、前記膨張弁を予め一定の初期開度まで動作させた後、前記圧縮機を起動して給湯運転を開始する制御装置とを備え、
この制御装置は、前日の給湯運転安定時の膨張弁開度を基に今回の給湯運転安定時の膨張弁目標開度を予測し、その目標開度と前記初期開度との間に中間開度を設定し、前記圧縮機を起動した後、前記初期開度から前記中間開度まで第１の動作速度で前記膨張弁の開度を制御し、前記中間開度に到達した後、前記目標開度まで前記第１の動作速度より小さい第２の動作速度で前記膨張弁の開度を制御することを特徴とするヒートポンプ式温水器。A compressor for compressing and discharging the sucked refrigerant;
A water heat exchanger for exchanging heat between the refrigerant pressurized by the compressor and the water used;
An expansion valve that is provided in the refrigerant passage downstream from the water heat exchanger and that can adjust the opening;
Before starting the compressor, after operating the expansion valve to a predetermined initial opening in advance, and a controller for starting the hot water supply operation by starting the compressor,
This control device predicts the target opening of the expansion valve at the time of stable hot water supply operation based on the opening of the expansion valve at the time of stable hot water supply operation on the previous day, and opens an intermediate opening between the target opening and the initial opening. After setting the degree and starting the compressor, the opening of the expansion valve is controlled at the first operating speed from the initial opening to the intermediate opening, and after reaching the intermediate opening, the target The heat pump water heater is characterized in that the opening degree of the expansion valve is controlled at a second operating speed smaller than the first operating speed until the opening degree.

請求項２に記載したヒートポンプ式温水器において、
前記制御装置は、給湯運転安定時の膨張弁開度を記憶する記憶回路を有し、この記憶回路は、運転毎に前記給湯運転安定時の膨張弁開度を更新することを特徴とするヒートポンプ式温水器。 In the heat pump type water heater according to claim 2,
The control device includes a storage circuit that stores an expansion valve opening when the hot water supply operation is stable, and the storage circuit updates the expansion valve opening when the hot water supply operation is stable for each operation. Water heater.

請求項１〜３に記載した何れかのヒートポンプ式温水器において、
外気温度が高くなる程、前記膨張弁の目標開度が大きく設定されることを特徴とするヒートポンプ式温水器。 In any one of heat pump type water heaters described in claims 1-3,
The heat pump water heater , wherein the target opening degree of the expansion valve is set larger as the outside air temperature becomes higher .

請求項１〜３に記載した何れかのヒートポンプ式温水器において、
給水温度が高くなる程、前記膨張弁の目標開度が大きく設定されることを特徴とするヒートポンプ式温水器。 In any one of heat pump type water heaters described in claims 1-3,
The heat pump water heater, wherein the target opening degree of the expansion valve is set larger as the feed water temperature becomes higher.

請求項１〜５に記載した何れかのヒートポンプ式温水器において、
前記水熱交換器に流入する利用水と前記水熱交換器から流出する冷媒との温度差が目標温度差ΔＴとなるように、前記膨張弁の開度を調節してサイクル内の高圧を制御していることを特徴とするヒートポンプ式温水器。 In any one of the heat pump water heaters according to claims 1 to 5 ,
The high pressure in the cycle is controlled by adjusting the opening of the expansion valve so that the temperature difference between the use water flowing into the water heat exchanger and the refrigerant flowing out of the water heat exchanger becomes a target temperature difference ΔT. heat pump water heater, characterized by that.

請求項１〜６に記載した何れかのヒートポンプ式温水器において、
ヒートポンプサイクルに使用する冷媒がＣＯ _２であることを特徴とするヒートポンプ式温水器。 In any one of the heat pump water heaters according to claims 1 to 6,
A heat pump water heater , wherein the refrigerant used in the heat pump cycle is CO ₂ .