JP3991216B2

JP3991216B2 - Hot water storage water heater

Info

Publication number: JP3991216B2
Application number: JP2002291474A
Authority: JP
Inventors: 興隆渡邊; 宗平岡; 次郎岡島
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2002-10-03
Filing date: 2002-10-03
Publication date: 2007-10-17
Anticipated expiration: 2022-10-03
Also published as: JP2004125306A

Description

【０００１】
【発明の属する技術分野】
本発明は、貯湯タンクの外部で、貯湯水と外部熱負荷との間で熱交換する貯湯式給湯器に関するものである。
【０００２】
【従来の技術】
従来の浴槽追焚き機能を備えた貯湯式給湯器においては、浴槽の追焚き時に、循環ポンプを運転して貯湯タンクの上部より循環回路に高温水を取り出し、風呂用熱交換器で浴槽水と熱交換させ、温度の低くなった中温水を貯湯タンクの下部に戻すことで浴槽水の追焚きを行っている（例えば、特許文献１参照）。
【０００３】
【特許文献１】
特開２００１−１０８２９２号公報（第４頁、図１）
【０００４】
【発明が解決しようとする課題】
しかしながら、上記のような従来の構成では、循環回路を流れる高温水の流量調整は行われておらず、循環ポンプの循環能力と配管抵抗などによって一義的に循環流量が決定されてしまう。このため、浴槽水の追焚き能力は高くできるものの、風呂用熱交換器を通過して浴槽に戻る湯の温度をコントロールすることができない。この結果、タンク循環回路から貯湯タンクへの戻り温度が高くなり、蛇口等で湯が給湯されて貯湯タンク下部に供給された水と混ざり、貯湯タンクの下部に中途半端なぬるま湯が形成され、タンク循環回路からの戻り温度が高いにもかかわらず、湯として使用できないという問題があった。
【０００５】
また、加熱手段として発熱体の代わりにヒートポンプサイクルを用いた室外機を利用して、貯湯タンクの下部より水を取り出し、室外機にて湯を作り、貯湯タンクの上部に沸き上げた湯を順次貯めていくように沸き上げを行なうヒートポンプ給湯器においては、風呂用熱交換器から貯湯タンクヘ戻される湯の温度が高いと、ヒートポンプ沸き上げ時の加熱効率（成績係数）が低下してしまうという問題がある。なお、ここでいう加熱効率とは、沸き上げ能力を消費電力で割ったものをさす。
【０００６】
本発明は、上記のような課題を解決するためになされたもので、貯湯タンク下部のぬるま湯の形成を防止し、かつ、ヒートポンプサイクルを用いた加熱方式においては、沸き上げ時の加熱効率（成績係数）の低下を防止できる貯湯式給湯器を提供することを目的とする。
【０００７】
【課題を解決するための手段】
本発明は、下部から給水され上部から出湯される貯湯タンクと、貯湯タンクの貯湯水を加熱するヒートポンプサイクルを用いた加熱手段と、貯湯タンクの上部から取り出した貯湯水を貯湯タンクに戻すタンク循環回路と、タンク循環回路を循環する貯湯水と外部熱負荷との間で熱交換を行なう熱交換器と、熱交換器の貯湯水の出口温度を検出する温度検出手段とを備えた貯湯式給湯器であって、タンク循環回路に循環流量を調整する循環流量調整弁を設けると共に、タンク循環回路の貯湯水を貯湯タンクに戻す戻し経路を複数設けてそのいずれかに切り替える流路切替手段を設け、外部熱負荷の加熱を行うとき、外部熱負荷が暖房装置のときは、流路切替手段により貯湯タンクに戻す戻し経路を貯湯タンクの上方に接続し、循環流量調整弁でタンク循環回路の循環流量を調整して貯湯タンクに戻す貯湯水の温度を所定温度よりも高くし、外部熱負荷が浴槽のときは、流路切替手段により貯湯タンクに戻す戻し経路を貯湯タンクの下方に接続し、循環流量調整弁でタンク循環回路の循環流量を調整して貯湯タンクに戻す貯湯水の温度を所定温度よりも低くするようにしたものである。
【０００８】
【発明の実施の形態】
［実施の形態１］
図１は本発明の実施の形態１に係るヒートポンプ給湯器の構成図、図２はヒートポンプ本体の構成図である。図１において、給湯本体１内に貯湯タンク２が配設され、この貯湯タンク２の下部には給水管３が接続されて給水管３には減圧弁４が設けられ、また、貯湯タンク２の上部には給湯管５が接続されて給湯管５には逃がし弁６が設けられている。貯湯タンク２の上下部にはタンク循環回路７が接続されており、タンク循環回路７は、貯湯タンク２内に貯湯された湯と外部熱負荷である浴槽８内の湯とを熱交換する風呂用熱交換器９と、貯湯タンク２内の湯をタンク循環回路７に循環させる循環ポンプ１０と、タンク循環回路７を通る湯の循環流量を調整する循環流量調整弁１１とによって構成されている。
浴槽８には風呂用熱交換器９の二次側である浴槽水循環回路１２が接続され、浴槽水循環回路１２には浴槽水を循環させる循環ポンプ１３が設けられている。
ヒートポンプ本体１４（後述する）には加熱循環回路１５が接続され、この加熱回路１５は貯湯タンク２の上下部と接続されており、加熱循環回路１５には循環ポンプ１６が設けられている。
【０００９】
貯湯タンク２内の残湯温度は、温度センサ１７ａ，１７ｂで検出する。また、風呂用熱交換器９への貯湯水の入口温度は貯湯水入口温度センサ１８ａで検出し、風呂用熱交換器９からの貯湯水の出口温度は貯湯水出口温度センサ１８ｂで検出し、風呂用熱交換器９への浴槽水の入口温度は浴槽水入口温度センサ１８ｃで検出し、風呂用熱交換器９の浴槽水の出口温度は浴槽水出口温度センサ１８ｄで検出する。さらに、ヒートポンプ本体１４の加熱動作を停止するために、温度センサ１９で入水温度を検出する。
そして、制御部２０で、各温度センサ１７，１７ａ，１７ｂ，１８ａ〜１８ｄの検出値を読込み、操作部２１の設定に基づいて、各循環ポンプ１０，１３，１６、及び循環流量調整弁１１を制御する。
ここで、循環流量調整弁１１を絞り、貯湯水のタンク循環回路７における循環量を少なくして、貯湯タンク２への戻り温度を所定温度（例えば６０℃）以下とし、貯湯タンク２下方に戻す。
【００１０】
図２において、ヒートポンプ本体１４は、圧縮機２２、圧縮機２２より吐出された高圧ガス冷媒と給湯用の水を熱交換する貯湯用熱交換器２３、膨脹弁２４、室外熱交換器２５、アキュームレータ２６、室外熱交換器２５に吸熱するために取り付けられたファン２７、及び貯湯タンク２の上下部とヒートポンプ本体１４とを接続する加熱循環回路１５によって構成されている。そして、貯湯用熱交換器２３の出口温度を、沸き上げ温度センサ２８で検出する。
【００１１】
次に、本実施の形態１における貯湯式給湯器の動作について説明する。まず、給水管３から給水された水は減圧弁４で所定圧に減圧され、貯湯タンク２に給水される。ここで、貯湯タンク２は常に満水状態となっている。貯湯タンク２内の水は循環ポンプ１６の運転により、貯湯タンク２の下部から加熱循環回路１５に取り出されてヒートポンプ本体１４の貯湯用熱交換器２３に導かれ、貯湯用熱交換器２３で熱交換されて加熱昇温され、貯湯タンク２の上部に戻される。そして、加熱循環回路１５を流れる流量は、沸き上げ温度センサ２８が操作部２１で設定された温度（例えば９０℃）になるように、循環ポンプ１６で調整される。これにより、貯湯タンク２の上部より９０℃の湯が少量づつ貯湯されていく。
【００１２】
ヒートポンプ方式による沸き上げは、温度センサ１９の温度が一定温度（例えば６０℃）以上になったら、貯湯タンク２が全量沸き上がったと判断して、終了する。
このとき、ヒートポンプ方式による沸き上げ加熱性能は、貯湯用熱交換器２３に入る水の温度が低いときは沸き上げの加熱効率が高いが、給湯用熱交換器２３に入る水の温度が高いときは沸き上げの加熱効率は低下する特性を持っている。
なお、沸き上げ時の貯湯タンク２の膨脹水は逃し弁６より排出される。
【００１３】
一般の蛇口などに給湯する場合は、蛇口を開くことによって、給湯管５を通して水源水圧により給湯され、貯湯タンク２下部には水が供給される。
【００１４】
次に、浴槽水の追焚き動作について説明する。操作部２１により、制御部２０が浴槽８の追焚き開始の指示を受けると、追焚き動作が開始される。追焚き動作が開始されると、まず循環ポンプ１３が動作して浴槽８内の湯が浴槽循環回路１２に導かれ、風呂用熱交換器９を通って浴槽８内に戻される。一方、循環ポンプ１０も動作して、貯湯タンク２の上部より高温の貯湯水がタンク循環回路７に導かれ、風呂用熱交換器９を通って貯湯タンク２の下部に戻される。このとき、風呂用熱交換器９は、貯湯タンク２内に貯湯された高温の貯湯水から低温の浴槽水に熱交換（伝熱）することで、浴槽水を入浴に適した温度に加熱昇温させる。
【００１５】
風呂用熱交換器９の近傍には、貯湯水入口温度センサ１８ａ、貯湯水出口温度センサ１８ｂ、浴槽水入口温度センサ１８ｃ、浴槽水出口温度センサ１８ｄが設けられており、これらの温度センサ１８ａ〜１８ｄで各部の温度を検出し、この温度により、循環流量調整弁１１を調整して追焚き制御を行なう。
【００１６】
次に、浴槽８の追焚きの制御動作について詳細に説明する。ここで、以下の説明のため、風呂用熱交換器９の貯湯水入口温度センサ１８ａの検出温度である入力値をＴｈｉ、貯湯水出口温度センサ１８ｂの検出温度である入力値をＴｈｏ、浴槽水入口温度センサ１８ｃの検出温度である入力値をＴｃｉ、浴槽水出口温度センサ１８ｄの検出温度である入力値をＴｃｏと定義する。
【００１７】
操作部２１の操作により、浴槽追焚きが開始されると、循環流量調整弁１１を調節してタンク循環回路７の循環量を少なくし、貯湯タンク２ヘの戻り温度、すなわち、貯湯水出口温度センサ１８ｂの入力値Ｔｈｏを所定温度（例えば６０℃）以下に制御して追焚きを行なう。
風呂用熱交換器９の浴槽水入口温度センサ１８ｃの入力値Ｔｃｉが、操作部２１などであらかじめ設定されている浴槽８の設定温度以上か否かを確認する。Ｔｃｉが設定温度以上ならば、循環ポンプ１０及び循環ポンプ１３をＯＦＦにして、浴槽８の追焚きを終了する。
Ｔｃｉが設定温度未満ならば、追焚きを継続する。
【００１８】
ここで、循環流量調整弁１１を調整し、タンク循環回路７の流量を制限しているので、追焚き加熱能力は制限され、Ｔｃｏを一定温度以下に押さえることができ、浴槽８に高温水が供給されることがなく、不快感を与えることはない。また、Ｔｈｏを低く抑えることができ、貯湯タンク２下部の水温が高くなることを防ぐことにより追焚きの加熱能力が低くなるものの、貯湯タンク２下部の水温の上昇を防止し、ヒートポンプ方式による沸き上げ時の加熱効率の低下を軽減することができる。
【００１９】
ところで、循環流量調整弁１１を全開にし、循環ポンプ１０及び循環ポンプ１３をＯＮにして、浴槽８の追焚きを行なった場合も同様の動作になるが、循環流量調整弁１１を全開にしているので、追焚きの加熱能力は高くなる（すなわち、浴槽８の中の湯を設定温度まで上昇させる時間が短くなる）。一方、浴槽水出口温度センサ１８ｄの入力値Ｔｃｏが高くなり、浴槽８内に高温水が供給されたり、貯湯水出口温度センサ１８ｂの入力値Ｔｈｏが高くなるために、貯湯タンク２下部の水温が高くなってしまい、ヒートポンプ方式による沸き上げ時の加熱効率が低くなってしまう。
【００２０】
このように、実施の形態１によれば、循環流量調整弁１１を調節し、タンク循環回路７の流量を制限しているため、追焚き加熱能力が制限され、Ｔｃｏを一定温度以下に抑えることができ、Ｔｈｏを所定温度より低く抑えられるので、タンク循環回路７の貯湯タンク２の下方に接続しても、貯湯タンク２下部の水温が高くなることを防ぐことにより、追焚きの加熱能力が低くなるものの、ヒートポンプ方式による沸き上げ時の加熱効率の低下を軽減することができる。
【００２１】
［実施の形態２］
図３は本発明の実施の形態２に係るヒートポンプ給湯器の構成図である。本発明においては、実施の形態１で示した浴槽８が例えば暖房装置である外部熱負荷３０に、風呂用熱交換器９が外部熱負荷用熱交換器３１に、浴槽水循環回路１２が外部熱循環回路３２に、浴槽水入口温度センサ１８ｃが外部熱負荷入口温度センサ３３ｃに、浴槽水出口温度センサ１８ｄが外部熱負荷出口温度センサ３３ｄになっている。そして、タンク循環回路７に流路切換弁３４が取付けてあり、流路切替弁３４で分岐して貯湯タンク２下方に接続される第１の戻し管３５ａと、貯湯タンク２上方に接続される第２の戻し管３５ｂを構成している。
【００２２】
外部熱負荷３０が暖房装置の場合、外部熱負荷３０に送水する温度、すなわち、外部熱負荷入口温度センサ３３ｃの入力値Ｔｃｉは浴槽水の場合より高くしなければならないため、タンク循環回路７の循環量は最大で、貯湯タンク２への戻り温度は高く、Ｔｈｏは所定温度（例えば６０℃）以上になり、流路切換弁３４によりタンク循環回路７は第２の戻し配管３５ｂを介して貯湯タンク２の上方に接続され、貯湯タンク２上部の残湯と混ざっても湯として使用可能である。また、蛇口等で湯が給湯されて貯湯タンク２下部に供給された水と混ざることがないため、ヒートポンプ方式による沸き上げ時の加熱効率の低下を防止することができる。
【００２３】
【発明の効果】
以上のように、本発明に係る貯湯式給湯器によれば、循環流量調整弁を調節して、タンク循環回路の貯湯タンクへの戻り温度を所定温度以下に制御して貯湯タンクの下方に戻し、貯湯タンク下部の水の温度上昇を抑制することで、ヒートポンプ方式による沸き上げ時の加熱効率の低下を防止することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態１に係るヒートポンプ式給湯器の構成図である。
【図２】図１のヒートポンプ本体の構成図である。
【図３】本発明の実施の形態２に係るヒートポンプ式給湯器の構成図である。
【符号の説明】
１給湯器本体、２貯湯タンク、７タンク循環回路、８浴槽、９風呂用熱交換器、１０循環ポンプ、１１循環流量調整弁（循環流量調整手段）、１２浴槽水循環回路、１４ヒートポンプ本体（加熱手段）、１５加熱循環回路、１８ａ〜１８ｄ温度センサ、３０外部熱負荷、３１外部熱負荷用熱交換器、３２外部熱負荷循環回路、３３ｃ〜３３ｄ温度検出手段、３４流路切換弁（流路切換手段）、３５ａ，３５ｂ戻し管。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hot water storage type water heater that performs heat exchange between hot water and an external heat load outside a hot water storage tank.
[0002]
[Prior art]
In a conventional hot water storage type hot water heater equipped with a bathtub reheating function, when the bathtub is reheated, a circulating pump is operated to extract hot water from the upper part of the hot water storage tank into the circulation circuit, and the bath heat exchanger The bath water is repurchased by returning heat to the lower part of the hot water storage tank with the medium-temperature water having undergone heat exchange (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
JP 2001-108292 A (page 4, FIG. 1)
[0004]
[Problems to be solved by the invention]
However, in the conventional configuration as described above, the flow rate of the high-temperature water flowing through the circulation circuit is not adjusted, and the circulation flow rate is uniquely determined by the circulation capacity of the circulation pump and the piping resistance. For this reason, although the ability to chase bathtub water can be made high, the temperature of the hot water which returns to a bathtub through a heat exchanger for baths cannot be controlled. As a result, the return temperature from the tank circulation circuit to the hot water storage tank becomes high, hot water is supplied from a faucet etc. and mixed with the water supplied to the lower part of the hot water storage tank, and half-warm hot water is formed at the lower part of the hot water storage tank. Despite the high return temperature from the circulation circuit, there was a problem that it could not be used as hot water.
[0005]
In addition, using an outdoor unit that uses a heat pump cycle instead of a heating element as a heating means, water is taken out from the lower part of the hot water storage tank, hot water is made in the outdoor unit, and hot water boiled up at the upper part of the hot water storage tank is sequentially added. In heat pump water heaters that boil as if they are stored, if the temperature of the hot water returned from the bath heat exchanger to the hot water storage tank is high, the heating efficiency (coefficient of performance) at the time of boiling the heat pump will decrease. There is. In addition, the heating efficiency here refers to the boiling capacity divided by the power consumption.
[0006]
The present invention has been made to solve the above-described problems, and prevents the formation of lukewarm water at the bottom of the hot water storage tank, and in the heating system using the heat pump cycle, the heating efficiency (results) It is an object of the present invention to provide a hot water storage type water heater that can prevent a decrease in the coefficient.
[0007]
[Means for Solving the Problems]
The present invention relates to a hot water storage tank that is supplied with water from the lower part and discharged from the upper part, a heating means using a heat pump cycle for heating the hot water stored in the hot water storage tank, and a tank circulation that returns the hot water extracted from the upper part of the hot water storage tank to the hot water storage tank. Hot water storage type hot water supply comprising a circuit, a heat exchanger for exchanging heat between hot water circulating in the tank circulation circuit and an external heat load, and a temperature detecting means for detecting an outlet temperature of the hot water of the heat exchanger The tank circulation circuit is provided with a circulation flow rate adjusting valve that adjusts the circulation flow rate, and a plurality of return paths for returning the hot water stored in the tank circulation circuit to the hot water storage tank and switching to one of them is provided. When heating the external heat load, when the external heat load is a heating device, a return path for returning to the hot water storage tank by the flow path switching means is connected above the hot water storage tank, and the circulation flow rate adjusting valve is used. If the temperature of the hot water returned to the hot water storage tank is adjusted to be higher than the specified temperature by adjusting the circulation flow rate of the tank circulation circuit and the external heat load is a bathtub, the return path for returning to the hot water storage tank by the flow path switching means The temperature of the hot water returned to the hot water storage tank is made lower than a predetermined temperature by connecting to the lower side and adjusting the circulation flow rate of the tank circulation circuit with the circulation flow rate adjusting valve .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
[Embodiment 1]
1 is a configuration diagram of a heat pump water heater according to Embodiment 1 of the present invention, and FIG. 2 is a configuration diagram of a heat pump main body. In FIG. 1, a hot water storage tank 2 is disposed in a hot water supply body 1, a water supply pipe 3 is connected to the lower part of the hot water storage tank 2, a pressure reducing valve 4 is provided in the water supply pipe 3, and A hot water supply pipe 5 is connected to the upper part, and a relief valve 6 is provided in the hot water supply pipe 5. A tank circulation circuit 7 is connected to the upper and lower portions of the hot water storage tank 2, and the tank circulation circuit 7 exchanges heat between hot water stored in the hot water storage tank 2 and hot water in the bathtub 8 that is an external heat load. A heat exchanger 9 for use, a circulation pump 10 for circulating hot water in the hot water storage tank 2 to the tank circulation circuit 7, and a circulation flow rate adjusting valve 11 for adjusting the circulation flow rate of hot water passing through the tank circulation circuit 7. .
A bathtub water circulation circuit 12 that is the secondary side of the bath heat exchanger 9 is connected to the bathtub 8, and the bathtub water circulation circuit 12 is provided with a circulation pump 13 that circulates the bathtub water.
A heating circulation circuit 15 is connected to the heat pump main body 14 (described later). The heating circuit 15 is connected to the upper and lower portions of the hot water storage tank 2, and the heating circulation circuit 15 is provided with a circulation pump 16.
[0009]
The remaining hot water temperature in the hot water storage tank 2 is detected by the temperature sensors 17a and 17b. The hot water inlet temperature to the bath heat exchanger 9 is detected by the hot water inlet temperature sensor 18a, and the hot water outlet temperature from the bath heat exchanger 9 is detected by the hot water outlet temperature sensor 18b. The bath water inlet temperature to the bath heat exchanger 9 is detected by the bath water inlet temperature sensor 18c, and the bath water outlet temperature of the bath heat exchanger 9 is detected by the bath water outlet temperature sensor 18d. Furthermore, in order to stop the heating operation of the heat pump main body 14, the incoming water temperature is detected by the temperature sensor 19.
Then, the control unit 20 reads the detection values of the temperature sensors 17, 17 a, 17 b, 18 a to 18 d, and sets the circulation pumps 10, 13, 16 and the circulation flow rate adjustment valve 11 based on the setting of the operation unit 21. Control.
Here, the circulation flow rate adjusting valve 11 is throttled to reduce the circulation amount in the hot water tank circulation circuit 7, the return temperature to the hot water storage tank 2 is set to a predetermined temperature (for example, 60 ° C.) or less, and returned to the lower side of the hot water storage tank 2. .
[0010]
In FIG. 2, the heat pump main body 14 includes a compressor 22, a hot water storage heat exchanger 23 that exchanges heat between the high-pressure gas refrigerant discharged from the compressor 22 and hot water supply water, an expansion valve 24, an outdoor heat exchanger 25, and an accumulator. 26, a fan 27 attached to absorb heat to the outdoor heat exchanger 25, and a heating circulation circuit 15 that connects the upper and lower portions of the hot water storage tank 2 and the heat pump main body 14. The outlet temperature of the hot water storage heat exchanger 23 is detected by the boiling temperature sensor 28.
[0011]
Next, the operation of the hot water storage type water heater in the first embodiment will be described. First, the water supplied from the water supply pipe 3 is reduced to a predetermined pressure by the pressure reducing valve 4 and supplied to the hot water storage tank 2. Here, the hot water storage tank 2 is always full. The water in the hot water storage tank 2 is taken out from the lower part of the hot water storage tank 2 to the heating circulation circuit 15 by the operation of the circulation pump 16, led to the hot water storage heat exchanger 23 of the heat pump main body 14, and heated by the hot water storage heat exchanger 23. It is exchanged, heated and heated, and returned to the upper part of the hot water storage tank 2. The flow rate flowing through the heating circuit 15 is adjusted by the circulation pump 16 so that the boiling temperature sensor 28 becomes a temperature set by the operation unit 21 (for example, 90 ° C.). Thereby, 90 degreeC hot water is stored little by little from the upper part of the hot water storage tank 2.
[0012]
When the temperature of the temperature sensor 19 becomes equal to or higher than a certain temperature (for example, 60 ° C.), it is determined that the hot water storage tank 2 has been boiled up, and the boiling by the heat pump method is finished.
At this time, when the temperature of the water entering the hot water storage heat exchanger 23 is low, the boiling heating performance by the heat pump system is high when the temperature of the water entering the hot water supply heat exchanger 23 is high. Has the characteristic that the heating efficiency of boiling is reduced.
The expanded water in the hot water storage tank 2 at the time of boiling is discharged from the relief valve 6.
[0013]
When hot water is supplied to a general faucet or the like, hot water is supplied by the water source water pressure through the hot water supply pipe 5 by opening the faucet, and water is supplied to the lower part of the hot water storage tank 2.
[0014]
Next, the bath water pursuit operation will be described. When the control unit 20 receives an instruction to start chasing the bathtub 8 by the operation unit 21, the chasing operation is started. When the chasing operation is started, first, the circulation pump 13 is operated so that the hot water in the bathtub 8 is guided to the bathtub circulation circuit 12 and returned to the bathtub 8 through the bath heat exchanger 9. On the other hand, the circulating pump 10 is also operated, and hot water stored at a temperature higher than that of the hot water storage tank 2 is guided to the tank circulation circuit 7 and returned to the lower part of the hot water storage tank 2 through the bath heat exchanger 9. At this time, the bath heat exchanger 9 heats the bath water to a temperature suitable for bathing by exchanging heat from the hot hot water stored in the hot water storage tank 2 to the cold bath water. Let warm.
[0015]
In the vicinity of the bath heat exchanger 9, a hot water storage inlet temperature sensor 18a, a hot water outlet temperature sensor 18b, a bath water inlet temperature sensor 18c, and a bath water outlet temperature sensor 18d are provided. In 18d, the temperature of each part is detected, and the circulating flow rate adjustment valve 11 is adjusted based on this temperature to perform additional control.
[0016]
Next, the chasing control operation of the bathtub 8 will be described in detail. Here, for the following explanation, the input value which is the detected temperature of the hot water inlet temperature sensor 18a of the bath heat exchanger 9 is Thi, the input value which is the detected temperature of the hot water outlet temperature sensor 18b is Th0, and the bath water. The input value that is the detected temperature of the inlet temperature sensor 18c is defined as Tci, and the input value that is the detected temperature of the bathtub water outlet temperature sensor 18d is defined as Tco.
[0017]
When bathtub reheating is started by the operation of the operation unit 21, the circulation flow rate adjustment valve 11 is adjusted to reduce the circulation amount of the tank circulation circuit 7, and the return temperature to the hot water tank 2, that is, the hot water outlet temperature. Tracking is performed by controlling the input value Th of the sensor 18b to a predetermined temperature (for example, 60 ° C.) or lower.
It is confirmed whether or not the input value Tci of the bath water inlet temperature sensor 18c of the bath heat exchanger 9 is equal to or higher than the set temperature of the bathtub 8 set in advance by the operation unit 21 or the like. If Tci is equal to or higher than the set temperature, the circulation pump 10 and the circulation pump 13 are turned off, and the chasing of the bathtub 8 is finished.
If Tci is less than the set temperature, the chasing is continued.
[0018]
Here, the circulation flow rate adjusting valve 11 is adjusted to restrict the flow rate of the tank circulation circuit 7, so that the additional heating capacity is limited, Tco can be kept below a certain temperature, and hot water is put in the bathtub 8. It is not supplied and does not cause discomfort. In addition, it is possible to keep the Th low and prevent the water temperature at the bottom of the hot water tank 2 from becoming high, thereby reducing the heating capacity of the reheating, but preventing the water temperature at the bottom of the hot water tank 2 from rising, It is possible to reduce a decrease in heating efficiency during raising.
[0019]
By the way, when the circulation flow rate adjustment valve 11 is fully opened, the circulation pump 10 and the circulation pump 13 are turned on, and the reheating of the bathtub 8 is performed, the same operation is performed, but the circulation flow rate adjustment valve 11 is fully opened. Therefore, the heating capacity for reheating increases (that is, the time for raising the hot water in the bathtub 8 to the set temperature is shortened). On the other hand, the input value Tco of the bath water outlet temperature sensor 18d is increased, and high-temperature water is supplied into the bathtub 8, or the input value Tho of the hot water outlet temperature sensor 18b is increased. It becomes high and the heating efficiency at the time of boiling by a heat pump system will become low.
[0020]
As described above, according to the first embodiment, the circulation flow rate adjustment valve 11 is adjusted and the flow rate of the tank circulation circuit 7 is limited, so that the additional heating capacity is limited and Tco is suppressed to a certain temperature or less. Since Th can be kept lower than the predetermined temperature, even if it is connected to the lower part of the hot water tank 2 of the tank circulation circuit 7, it prevents the water temperature at the lower part of the hot water tank 2 from being increased, thereby increasing the heating capacity for reheating. Although it becomes low, the fall of the heating efficiency at the time of boiling by a heat pump system can be reduced.
[0021]
[Embodiment 2]
FIG. 3 is a configuration diagram of a heat pump water heater according to Embodiment 2 of the present invention. In the present invention, the bathtub 8 shown in the first embodiment is, for example, an external heat load 30 that is a heating device, the bath heat exchanger 9 is an external heat load heat exchanger 31, and the bathtub water circulation circuit 12 is an external heat. In the circulation circuit 32, the bathtub water inlet temperature sensor 18c is an external thermal load inlet temperature sensor 33c, and the bathtub water outlet temperature sensor 18d is an external thermal load outlet temperature sensor 33d. A flow path switching valve 34 is attached to the tank circulation circuit 7, and a first return pipe 35 a branched by the flow path switching valve 34 and connected to the lower side of the hot water storage tank 2 is connected to the upper side of the hot water storage tank 2. A second return pipe 35b is configured.
[0022]
When the external heat load 30 is a heating device, the temperature sent to the external heat load 30, that is, the input value Tci of the external heat load inlet temperature sensor 33 c must be higher than in the case of bath water. The circulation amount is the maximum, the return temperature to the hot water storage tank 2 is high, the Th becomes a predetermined temperature (for example, 60 ° C.) or higher, and the tank circulating circuit 7 is stored in the hot water storage via the second return pipe 35b by the flow path switching valve 34. Even if it is connected to the upper part of the tank 2 and mixed with the remaining hot water at the upper part of the hot water storage tank 2, it can be used as hot water. Moreover, since hot water is not supplied with the hot water supplied from the faucet or the like and supplied to the lower part of the hot water storage tank 2, it is possible to prevent a reduction in heating efficiency during boiling by the heat pump system.
[0023]
【The invention's effect】
As described above, according to the hot water storage type hot water heater according to the present invention, the return flow rate of the tank circulation circuit to the hot water storage tank is controlled to be equal to or lower than the predetermined temperature by adjusting the circulation flow rate adjustment valve and returned to the lower side of the hot water storage tank. By suppressing the temperature rise of the water in the lower part of the hot water storage tank, it is possible to prevent a decrease in heating efficiency at the time of boiling by the heat pump method.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a heat pump type water heater according to a first embodiment of the present invention.
2 is a configuration diagram of the heat pump main body of FIG. 1. FIG.
FIG. 3 is a configuration diagram of a heat pump type water heater according to Embodiment 2 of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Water heater body, 2 Hot water storage tank, 7 Tank circulation circuit, 8 Bathtub, 9 Bath heat exchanger, 10 Circulation pump, 11 Circulation flow rate adjustment valve (circulation flow rate adjustment means), 12 Bathtub water circulation circuit, 14 Heat pump body (Heating Means), 15 heating circulation circuit, 18a to 18d temperature sensor, 30 external heat load, 31 heat exchanger for external heat load, 32 external heat load circulation circuit, 33c to 33d temperature detection means, 34 flow path switching valve (flow path) Switching means), 35a, 35b return pipe.

Claims

A hot water storage tank supplied with water from the lower part and discharged from the upper part, a heating means using a heat pump cycle for heating the hot water stored in the hot water storage tank, and a tank circulation circuit for returning the hot water extracted from the upper part of the hot water storage tank to the hot water storage tank A hot water storage type comprising: a heat exchanger for exchanging heat between the hot water circulating in the tank circulation circuit and an external heat load; and a temperature detecting means for detecting an outlet temperature of the hot water in the heat exchanger In the water heater,
A circulation flow rate adjusting valve for adjusting a circulation flow rate is provided in the tank circulation circuit, and a plurality of return paths for returning the hot water stored in the tank circulation circuit to the hot water storage tank are provided, and flow path switching means for switching to any one of them is provided, when performing the heating of the external heat load, when the external heat load is the heating device connects the return path back to the hot water storage tank by the flow path switching unit above the hot water storage tank, the tank before Symbol circulation flow rate control valve When the temperature of the hot water returning to the hot water storage tank is adjusted to be higher than a predetermined temperature by adjusting the circulation flow rate of the circulation circuit, and the external heat load is a bathtub, the return path for returning to the hot water storage tank by the flow path switching means is connect below the hot water storage tank, to the pre-Symbol temperature circulation flow rate adjusted to the hot water back to the hot water storage tank of the circulation flow rate control valve in the tank circulation circuit, characterized in that below a predetermined temperature Hot water storage type water heater.