JP5558937B2

JP5558937B2 - Heat pump type water heater

Info

Publication number: JP5558937B2
Application number: JP2010148410A
Authority: JP
Inventors: 基阿部; 貴幸阿部; 伊藤　　隆; 元泰佐藤; 豪宮尾; 亮松尾
Original assignee: Corona Corp
Current assignee: Corona Corp
Priority date: 2010-06-30
Filing date: 2010-06-30
Publication date: 2014-07-23
Anticipated expiration: 2030-06-30
Also published as: JP2012013267A

Description

この発明は、貯湯タンク内の湯水をヒートポンプで加熱するヒートポンプ式給湯装置に関するものである。 The present invention relates to a heat pump hot water supply apparatus for heating hot water in a hot water storage tank with a heat pump.

従来のこの種のヒートポンプ式給湯装置においては、下部に給水管が接続され、上部に出湯管が接続された貯湯タンクと、圧縮機、凝縮器としての水冷媒熱交換器、減圧器としての電子膨張弁、蒸発器としての空気熱交換器を冷媒配管で環状に接続したヒートポンプサイクルを有したヒートポンプ式加熱手段と、貯湯タンク下部から取り出した湯水を水冷媒熱交換器の水側に流通させ貯湯タンク上部に戻す循環ポンプを有した加熱循環回路とを備え、貯湯タンク内の湯水をヒートポンプ式加熱手段に循環させ沸き上げるようにしたものであった。 In this type of conventional heat pump hot water supply apparatus, a hot water storage tank having a water supply pipe connected to the lower part and a hot water discharge pipe connected to the upper part, a water refrigerant heat exchanger as a compressor, a condenser, and an electron as a pressure reducer Heat pump type heating means having a heat pump cycle in which an air heat exchanger as an expansion valve and an evaporator is connected in an annular shape with refrigerant piping, and hot water taken out from the lower part of the hot water storage tank is circulated to the water side of the water refrigerant heat exchanger to store hot water And a heating circulation circuit having a circulation pump for returning to the upper part of the tank, and the hot water in the hot water storage tank is circulated to the heat pump heating means to be boiled up.

ここで、前記ヒートポンプ式加熱手段は、その運転効率が高効率となる状態で運転するように制御されるものであり、その制御方法として、圧縮機から吐出される冷媒の吐出温度が予め設定された目標吐出温度となるように、電子膨張弁の開度を制御するものがあった（例えば、特許文献１参照。）。 Here, the heat pump heating means is controlled so as to operate in a state in which the operation efficiency is high. As a control method, the discharge temperature of the refrigerant discharged from the compressor is set in advance. Some control the opening of the electronic expansion valve so that the target discharge temperature is reached (see, for example, Patent Document 1).

特開２００２−１８８８６０号公報JP 2002-188860 A

ところで、従来のヒートポンプ給湯装置において、貯湯タンク内の湯水の沸き上げが進み、沸き上げ終了時（沸き終い時）が近づくと、水冷媒熱交換器に流入する湯水の入水温度が上昇してくる。そうすると、ヒートポンプサイクルの状態は、図５の鎖線で示した安定時の状態から実線で示した沸き終い時の状態となる。この沸き終い時には、水冷媒熱交換器に流入する湯水の入水温度が上昇すると共に、水冷媒熱交換器から流出する冷媒温度も上昇していく。その状態で、圧縮機から吐出される冷媒の吐出温度が予め設定された目標吐出温度に保たれるよう電子膨張弁の開度を制御すると、圧縮機の吐出温度と水冷媒熱交換器から流出する冷媒温度との温度差が必要以上に小さくなり、運転効率が最大となる比エンタルピー差を保てず、効率の悪い運転を行ってしまうという問題を有するものであった。 By the way, in the conventional heat pump water heater, when the boiling of hot water in the hot water storage tank proceeds and the boiling end (at the end of boiling) approaches, the incoming temperature of the hot water flowing into the water-refrigerant heat exchanger increases. come. If it does so, the state of a heat pump cycle will be in the state at the time of the end of boiling shown with the continuous line from the state of the stable time shown with the chain line of FIG. At the end of boiling, the incoming temperature of hot water flowing into the water-refrigerant heat exchanger increases, and the temperature of refrigerant flowing out of the water-refrigerant heat exchanger also increases. In this state, if the opening of the electronic expansion valve is controlled so that the discharge temperature of the refrigerant discharged from the compressor is maintained at a preset target discharge temperature, the discharge temperature of the compressor and the water refrigerant heat exchanger will flow out. The temperature difference from the refrigerant temperature to be reduced is unnecessarily small, the specific enthalpy difference that maximizes the operation efficiency cannot be maintained, and the operation is inefficient.

そこで、この発明は上記課題を解決するために、特に請求項１ではその構成を、湯水を貯湯する貯湯タンクと、圧縮機、水冷媒熱交換器、減圧器、蒸発器を備えたヒートポンプ式加熱手段と、該ヒートポンプ式加熱手段の前記水冷媒熱交換器の水側と前記貯湯タンクとを環状に接続する加熱循環回路と、前記貯湯タンク内の湯水を目標沸き上げ温度に加熱するよう前記ヒートポンプ式加熱手段を制御する制御手段とを備えたヒートポンプ式給湯装置において、前記制御手段は、前記圧縮機から吐出される冷媒の吐出温度と前記水冷媒熱交換器から流出する冷媒の流出温度との温度差が、所定の目標温度差となるように前記減圧器の開度を制御し、前記所定の目標温度差は、前記目標沸き上げ温度と外気温度と前記水冷媒熱交換器に流入する湯水の入水温度とに基づいて算出するものとした。
Accordingly, in order to solve the above-mentioned problems, the present invention is particularly configured as claimed in claim 1, a heat pump heating system including a hot water storage tank for storing hot water, a compressor, a water refrigerant heat exchanger, a decompressor, and an evaporator. Means, a heating circulation circuit for annularly connecting the water side of the water-refrigerant heat exchanger of the heat pump heating means and the hot water storage tank, and the heat pump for heating the hot water in the hot water storage tank to a target boiling temperature In the heat pump type hot water supply apparatus comprising a control means for controlling the heating means, the control means is configured to calculate a discharge temperature of the refrigerant discharged from the compressor and an outflow temperature of the refrigerant flowing out of the water refrigerant heat exchanger. hot water temperature difference, and controlling the opening of said decompressor so that a predetermined target temperature difference, the predetermined target temperature difference flowing into the water-refrigerant heat exchanger and the target boiling temperature and outside air temperature And it shall be calculated on the basis of the water inlet temperature.

また、請求項２では、湯水を貯湯する貯湯タンクと、圧縮機、水冷媒熱交換器、減圧器、蒸発器を備えたヒートポンプ式加熱手段と、該ヒートポンプ式加熱手段の前記水冷媒熱交換器の水側と前記貯湯タンクとを環状に接続する加熱循環回路と、前記貯湯タンク内の湯水を目標沸き上げ温度に加熱するよう前記ヒートポンプ式加熱手段を制御する制御手段とを備えたヒートポンプ式給湯装置において、前記制御手段は、前記圧縮機から吐出される冷媒の吐出温度と前記水冷媒熱交換器から流出する冷媒の流出温度との温度差が、所定の目標温度差となるように前記減圧器の開度を制御し、前記所定の目標温度差は、前記目標沸き上げ温度と外気温度と前記水冷媒熱交換器に流入する湯水の入水温度とに基づいて、前記外気温度が高くなる程、前記所定の目標温度差の値が小さくなり、前記入水温度が高くなる程、前記所定の目標温度差の値が小さくなり、前記目標沸き上げ温度が高くなる程、前記所定の目標温度差の値が大きくなるように算出するものとした。
Further, in claim 2, a hot water storage tank for storing hot water, a heat pump type heating means including a compressor, a water refrigerant heat exchanger, a decompressor, and an evaporator, and the water refrigerant heat exchanger of the heat pump type heating means A heat pump hot water supply comprising: a heating circuit that annularly connects the water side of the hot water storage tank and the hot water storage tank; and a control means that controls the heat pump heating means to heat the hot water in the hot water storage tank to a target boiling temperature In the apparatus, the control means reduces the pressure so that a temperature difference between a discharge temperature of the refrigerant discharged from the compressor and an outflow temperature of the refrigerant flowing out of the water refrigerant heat exchanger becomes a predetermined target temperature difference. The predetermined target temperature difference is such that the higher the outside air temperature is, the higher the outside air temperature is based on the target boiling temperature, the outside air temperature, and the incoming water temperature flowing into the water-refrigerant heat exchanger. , The value of the predetermined target temperature difference decreases, the higher the incoming water temperature, the smaller the predetermined target temperature difference value, and the higher the target boiling temperature, the lower the predetermined target temperature difference. The value was calculated so as to increase .

この発明の請求項１によれば、貯湯タンク内の湯水を沸き上げる際に、制御手段は、圧縮機から吐出される冷媒の吐出温度と水冷媒熱交換器から流出する冷媒の流出温度との温度差が、所定の目標温度差となるように減圧器の開度を制御することで、沸き上げ中、運転効率が高効率となる比エンタルピー差を保ちながらヒートポンプ式加熱手段を運転させることができるものである。 According to the first aspect of the present invention, when boiling the hot water in the hot water storage tank, the control means uses the discharge temperature of the refrigerant discharged from the compressor and the outflow temperature of the refrigerant flowing out of the water refrigerant heat exchanger. By controlling the opening of the decompressor so that the temperature difference becomes a predetermined target temperature difference, the heat pump heating means can be operated while maintaining the specific enthalpy difference that makes the operating efficiency high during boiling. It can be done.

さらに、減圧器の開度を制御することで、圧縮機から吐出される冷媒の吐出温度および水冷媒熱交換器から流出する冷媒の流出温度の双方が変化するため、減圧器の開度変化に対する吐出温度と流出温度との温度差の温度変化量が大きく、吐出温度と流出温度との温度差を所定の目標温度差とするまでの制御速度が速く、すばやく高効率で運転させることができ、また、所定の目標温度差を目標沸き上げ温度、外気温度、入水温度に基づき算出するので、外気温度や入水温度といった条件が刻々と変化する沸き上げ時において、その時その時で運転効率が高効率となる所定の目標温度差を確実に求めることができ、ヒートポンプ式加熱手段を高効率で運転させることができるものである。
Furthermore, by controlling the opening of the decompressor, both the discharge temperature of the refrigerant discharged from the compressor and the outflow temperature of the refrigerant flowing out of the water-refrigerant heat exchanger change. The temperature change amount of the temperature difference between the discharge temperature and the outflow temperature is large, the control speed is high until the temperature difference between the discharge temperature and the outflow temperature becomes the predetermined target temperature difference, and it can be operated quickly and efficiently . In addition, since the predetermined target temperature difference is calculated based on the target boiling temperature, outside air temperature, and incoming water temperature, when the boiling temperature changes constantly, such as the outside air temperature and the incoming water temperature, the operating efficiency is high at that time. Thus, the predetermined target temperature difference can be obtained with certainty, and the heat pump heating means can be operated with high efficiency .

また、請求項２によれば、貯湯タンク内の湯水を沸き上げる際に、制御手段は、圧縮機から吐出される冷媒の吐出温度と水冷媒熱交換器から流出する冷媒の流出温度との温度差が、所定の目標温度差となるように減圧器の開度を制御することで、沸き上げ中、運転効率が高効率となる比エンタルピー差を保ちながらヒートポンプ式加熱手段を運転させることができ、さらに、減圧器の開度を制御することで、圧縮機から吐出される冷媒の吐出温度および水冷媒熱交換器から流出する冷媒の流出温度の双方が変化するため、減圧器の開度変化に対する吐出温度と流出温度との温度差の温度変化量が大きく、吐出温度と流出温度との温度差を所定の目標温度差とするまでの制御速度が速く、すばやく高効率で運転させることができ、所定の目標温度差を目標沸き上げ温度、外気温度、入水温度に基づき、外気温度が高くなる程、所定の目標温度差の値が小さくなり、入水温度が高くなる程、所定の目標温度差の値が小さくなり、目標沸き上げ温度が高くなる程、前記所定の目標温度差の値が大きくなるように算出するので、外気温度や入水温度といった条件が刻々と変化する沸き上げ時において、その時その時で運転効率が高効率となる所定の目標温度差を確実に求めることができ、ヒートポンプ式加熱手段を高効率で運転させることができるものである。 According to claim 2, when boiling the hot water in the hot water storage tank, the control means is a temperature between a discharge temperature of the refrigerant discharged from the compressor and an outflow temperature of the refrigerant flowing out of the water refrigerant heat exchanger. By controlling the opening of the decompressor so that the difference becomes a predetermined target temperature difference, the heat pump heating means can be operated while maintaining the specific enthalpy difference that makes the operating efficiency high during boiling. Furthermore, by controlling the opening of the decompressor, both the discharge temperature of the refrigerant discharged from the compressor and the outflow temperature of the refrigerant flowing out of the water-refrigerant heat exchanger change. The temperature change amount of the temperature difference between the discharge temperature and the outflow temperature is large, the control speed is high until the temperature difference between the discharge temperature and the outflow temperature becomes the predetermined target temperature difference, and it can be operated quickly and efficiently. a given target temperature Based difference target boiling temperature, outside air temperature, the incoming water temperature, as the outside air temperature is high, the value of the predetermined target temperature difference becomes smaller, as the incoming water temperature is high, the value of the predetermined target temperature difference is small The higher the target boiling temperature is, the larger the value of the predetermined target temperature difference is calculated.Therefore, when boiling is performed when conditions such as the outside air temperature and the incoming water temperature are constantly changing, the operating efficiency at that time is A predetermined target temperature difference with high efficiency can be obtained reliably, and the heat pump heating means can be operated with high efficiency.

この発明のヒートポンプ式給湯装置の一実施形態の概略構成図。The schematic block diagram of one Embodiment of the heat pump type hot water supply apparatus of this invention. 同一実施形態の電子膨張弁の開度と制御パラメータとの関係を示した図。The figure which showed the relationship between the opening degree of the electronic expansion valve of the same embodiment, and a control parameter. 同一実施形態の沸き終い時のヒートポンプサイクルの状態と従来の沸き終い時のヒートポンプサイクルの状態とを比較した図。The figure which compared the state of the heat pump cycle at the time of the end of boiling of the same embodiment, and the state of the heat pump cycle at the time of the end of the conventional boiling. この発明のヒートポンプ式給湯装置の他の実施形態の概略構成図。The schematic block diagram of other embodiment of the heat pump type hot-water supply apparatus of this invention. 従来のヒートポンプ式給湯装置の沸き上げ運転時のヒートポンプサイクルの状態を示した図。The figure which showed the state of the heat pump cycle at the time of the boiling operation of the conventional heat pump type hot-water supply apparatus.

次に、本発明の一実施形態について図面に基づいて説明する。
１は湯水を貯湯する貯湯タンク２を有した貯湯タンクユニット、３は貯湯タンク２内の湯水を加熱するヒートポンプ式加熱手段、４は前記貯湯タンク２の下部に接続された加熱往き管５および前記貯湯タンク２の上部に接続された加熱戻り管６からなり、貯湯タンク２とヒートポンプ式加熱手段３とを湯水が循環するよう環状に接続する加熱循環回路、７は前記貯湯タンク２の下部に接続され貯湯タンク２に水を給水する給水管、８は前記貯湯タンク２の上部に接続され貯湯されている高温水を出湯する出湯管である。 Next, an embodiment of the present invention will be described with reference to the drawings.
1 is a hot water storage tank unit having a hot water storage tank 2 for storing hot water, 3 is a heat pump heating means for heating the hot water in the hot water storage tank 2, 4 is a heating forward pipe 5 connected to the lower part of the hot water storage tank 2, and A heating circulation circuit comprising a heating return pipe 6 connected to the upper part of the hot water storage tank 2 and connecting the hot water storage tank 2 and the heat pump type heating means 3 in an annular shape so that hot water circulates, and 7 is connected to the lower part of the hot water storage tank 2 A hot water supply pipe 8 for supplying water to the hot water storage tank 2 and a hot water discharge pipe 8 connected to the upper part of the hot water storage tank 2 for discharging hot water stored therein.

９は給水管７から分岐された給水バイパス管、１０は出湯管８からの湯と給水バイパス管９からの水を混合して給湯設定温度の湯とする混合弁、１１は混合弁１０で混合後の給湯温度を検出する給湯温度センサ、１２は貯湯タンク２の側面上下にわたり複数設けられ、貯湯タンク２内の湯の温度を検出する貯湯温度センサ、１３は前記貯湯タンクユニット１内の各センサの出力を受けて各機器の動作を制御する貯湯制御手段である。 9 is a water supply bypass pipe branched from the water supply pipe 7, 10 is a mixing valve that mixes hot water from the hot water discharge pipe 8 and water from the water supply bypass pipe 9 to make hot water at a hot water supply set temperature, and 11 is mixed by the mixing valve 10 A plurality of hot water supply temperature sensors 12 for detecting a hot water supply temperature later, a plurality of hot water storage temperature sensors 12 for detecting the temperature of hot water in the hot water storage tank 2, and a plurality of sensors 12 in the hot water storage tank unit 1. Is a hot water storage control means for controlling the operation of each device.

前記ヒートポンプ式加熱手段３は、冷媒を圧縮する圧縮機１４と、圧縮機１４から吐出された冷媒を流通させる冷媒側の流路と加熱往き管５からの湯水を加熱戻り管６に流通させる水側の流路とを有し、高温高圧の冷媒と貯湯タンク２内の湯水とを熱交換する水冷媒熱交換器１５と、水冷媒熱交換器１５通過後の冷媒を減圧させる減圧器としての電子膨張弁１６と、電子膨張弁１６からの低温低圧の冷媒を蒸発させる蒸発器としての空気熱交換器１７とを冷媒配管で環状に接続したヒートポンプサイクル１８と、水冷媒熱交換器１５の水側の加熱循環回路４途中に設けられて貯湯タンク２の湯水を循環させる加熱循環ポンプ１９とを備えており、ヒートポンプサイクル１８内には冷媒として二酸化炭素が用いられて超臨界ヒートポンプサイクルを構成しているものである。 The heat pump type heating means 3 includes a compressor 14 for compressing refrigerant, a refrigerant-side flow path for circulating the refrigerant discharged from the compressor 14, and water for circulating hot water from the heating forward pipe 5 to the heating return pipe 6. A water refrigerant heat exchanger 15 that exchanges heat between the high-temperature and high-pressure refrigerant and the hot water in the hot water storage tank 2, and a decompressor that depressurizes the refrigerant after passing through the water refrigerant heat exchanger 15. A heat pump cycle 18 in which an electronic expansion valve 16 and an air heat exchanger 17 as an evaporator for evaporating the low-temperature and low-pressure refrigerant from the electronic expansion valve 16 are connected in an annular shape by a refrigerant pipe, and water in the water-refrigerant heat exchanger 15 And a heating circulation pump 19 that circulates the hot water in the hot water storage tank 2 provided in the middle of the heating circulation circuit 4 on the side. Carbon dioxide is used as a refrigerant in the heat pump cycle 18 so that it is a supercritical heat pump cycle. Those that make up the.

２０は圧縮機１４と水冷媒熱交換器１５との間に設けられ、圧縮機１４から吐出される冷媒の吐出温度を検出する吐出温度センサ、２１は水冷媒熱交換器１５と電子膨張弁１６との間に設けられ、水冷媒熱交換器１５の冷媒側から流出し電子膨張弁１６に向かう冷媒の温度を検出する流出温度センサ、２２は空気熱交換器１７の空気入口側に設けられ、外気温度を検出する外気温度センサ、２３は水冷媒熱交換器１５の水側に流入する入水温度を検出する入水温度センサ、２４は水冷媒熱交換器１５の水側から貯湯タンク２に向かって流出する沸き上げ温度を検出する沸き上げ温度センサである。 A discharge temperature sensor 20 is provided between the compressor 14 and the water refrigerant heat exchanger 15 to detect the discharge temperature of the refrigerant discharged from the compressor 14, and 21 is a water refrigerant heat exchanger 15 and an electronic expansion valve 16. And an outflow temperature sensor 22 for detecting the temperature of the refrigerant flowing out from the refrigerant side of the water refrigerant heat exchanger 15 toward the electronic expansion valve 16, 22 is provided on the air inlet side of the air heat exchanger 17, An outside air temperature sensor that detects the outside air temperature, 23 is an incoming water temperature sensor that detects the incoming water temperature that flows into the water side of the water refrigerant heat exchanger 15, and 24 is a water side from the water refrigerant heat exchanger 15 toward the hot water storage tank 2. It is a boiling temperature sensor which detects the boiling temperature which flows out.

２５は前記ヒートポンプ式加熱手段３内の各センサの出力を受けて各機器の動作を制御する制御手段としての加熱制御手段で、貯湯制御手段１３と通信可能に接続され、貯湯制御手段１３と連携して作動するものである。 Reference numeral 25 denotes a heating control means as a control means for receiving the output of each sensor in the heat pump type heating means 3 to control the operation of each device. The heating control means 25 is communicably connected to the hot water storage control means 13 and cooperates with the hot water storage control means 13 It operates as follows.

次に、この一実施形態の動作について説明する。
深夜時間帯となると、貯湯制御手段１３は貯湯タンク２内の湯水が所定の目標沸き上げ温度になるように沸き上げ運転を開始するよう加熱制御手段２５へ沸き上げ開始命令を指示する。そして、加熱制御手段２５は、沸き上げ運転において、前記目標沸き上げ温度および外気温度センサ２２で検出した外気温度に応じて設定される運転周波数で動作するように圧縮機１４を制御すると共に、吐出温度センサ２０の検出する冷媒温度と流出温度センサ２１の検出する冷媒温度との温度差ΔＨが所定の目標温度差ΔＨｍとなるように電子膨張弁１６の開度を所定の周期でフィードバック制御する。同時に、加熱制御手段２５は沸き上げ温度センサ２４で検出する水冷媒熱交換器１５で加熱された湯が目標沸き上げ温度になるように加熱循環ポンプ１９の回転数をフィードバック制御する。 Next, the operation of this embodiment will be described.
In the midnight time zone, the hot water storage control means 13 instructs the heating control means 25 to start a boiling operation so as to start the boiling operation so that the hot water in the hot water storage tank 2 reaches a predetermined target boiling temperature. The heating control means 25 controls the compressor 14 to operate at the operation frequency set according to the target boiling temperature and the outside air temperature detected by the outside air temperature sensor 22 in the boiling operation, and discharge The opening degree of the electronic expansion valve 16 is feedback-controlled at a predetermined cycle so that the temperature difference ΔH between the refrigerant temperature detected by the temperature sensor 20 and the refrigerant temperature detected by the outflow temperature sensor 21 becomes a predetermined target temperature difference ΔHm. At the same time, the heating control means 25 feedback-controls the rotational speed of the heating circulation pump 19 so that the hot water heated by the water refrigerant heat exchanger 15 detected by the boiling temperature sensor 24 reaches the target boiling temperature.

なお、前記所定の目標沸き上げ温度は、過去の給湯量の最大値や平均値等の給湯実績から翌日の給湯量の予測量を確保できるように貯湯制御手段１３によって算出されるもので、６５℃から９０℃の範囲で決定されるものである。 The predetermined target boiling temperature is calculated by the hot water storage control means 13 so as to ensure the predicted amount of the hot water supply amount on the next day from the hot water supply results such as the maximum value and the average value of the past hot water supply amount. It is determined in the range from 0C to 90C.

また、加熱制御手段２５は、前記所定の目標温度差ΔＨｍを前記目標沸き上げ温度と、外気温度センサ２２の検出する外気温度と、入水温度センサ２３の検出する入水温度とに基づいて、次式により算出する。
ΔＨｍ＝外気温度×Ａ＋入水温度×Ｂ＋目標沸き上げ温度×Ｃ＋Ｄ
（ここで、Ａ、Ｂは負の係数、Ｃは正の係数、Ｄは固定値である。） The heating control means 25 determines the predetermined target temperature difference ΔHm based on the target boiling temperature, the outside air temperature detected by the outside air temperature sensor 22, and the incoming water temperature detected by the incoming water temperature sensor 23. Calculated by
ΔHm = Outside air temperature × A + Incoming water temperature × B + Target boiling temperature × C + D
(Here, A and B are negative coefficients, C is a positive coefficient, and D is a fixed value.)

前記所定の目標温度差ΔＨｍは、上式より外気温度が高くなる程、値が小さくなっていき、入水温度が高くなる程、値が小さくなっていき、目標沸き上げ温度が高くなる程、値が大きくなるものであり、外気温度や入水温度といった条件が刻々と変化する沸き上げ運転中において、その時その時でヒートポンプ式加熱手段３の運転効率が最大効率となる所定の目標温度差ΔＨｍを確実に求めることができ、ヒートポンプ式加熱手段３を高効率で運転させることができるものである。なお、前記所定の目標温度差ΔＨｍの算出は沸き上げ運転中常時行われるものであってもよく、電子膨張弁１６の開度をフィードバック制御する所定の周期にあわせて行ってもよいものである。 The predetermined target temperature difference ΔHm becomes smaller as the outside air temperature becomes higher than the above formula, and the value becomes smaller as the incoming water temperature becomes higher, and the value becomes higher as the target boiling temperature becomes higher. During the boiling operation in which conditions such as the outside air temperature and the incoming water temperature change every moment, the predetermined target temperature difference ΔHm at which the operating efficiency of the heat pump type heating means 3 becomes the maximum efficiency at that time can be ensured. The heat pump heating means 3 can be operated with high efficiency. The calculation of the predetermined target temperature difference ΔHm may be performed constantly during the boiling operation, or may be performed in accordance with a predetermined cycle for feedback control of the opening degree of the electronic expansion valve 16. .

先に説明したとおり、沸き上げ運転の際、加熱制御手段２５は、吐出温度センサ２０の検出する冷媒温度と流出温度センサ２１の検出する冷媒温度との温度差ΔＨが、算出した所定の目標温度差ΔＨｍとなるように電子膨張弁１６の開度を制御しているが、具体的には、ΔＨ＜ΔＨｍの場合は、電子膨張弁１６の開度を閉じる方向に制御し、ΔＨ＞ΔＨｍの場合は、電子膨張弁１６の開度を開く方向に制御するものである。 As described above, during the boiling operation, the heating control unit 25 determines that the temperature difference ΔH between the refrigerant temperature detected by the discharge temperature sensor 20 and the refrigerant temperature detected by the outflow temperature sensor 21 is a predetermined target temperature calculated. The opening degree of the electronic expansion valve 16 is controlled so as to be the difference ΔHm. Specifically, when ΔH <ΔHm, the opening degree of the electronic expansion valve 16 is controlled in the closing direction so that ΔH> ΔHm. In this case, the opening degree of the electronic expansion valve 16 is controlled in the opening direction.

ここで、沸き上げ運転中のある一定条件下での電子膨張弁１６の開度に対する制御パラメータの関係について、図２を用いて説明するが、横軸は電子膨張弁１６の開度、縦軸は電子膨張弁１６の開度制御によって制御される制御パラメータであり、ここでは圧縮機１４から吐出され吐出温度センサ２０で検出される冷媒の吐出温度と水冷媒熱交換器１５から流出し流出温度センサ２１の検出する冷媒の流出温度との温度差とする。 Here, the relationship of the control parameter with respect to the opening degree of the electronic expansion valve 16 under a certain condition during the boiling operation will be described with reference to FIG. Is a control parameter controlled by opening degree control of the electronic expansion valve 16. Here, the refrigerant discharge temperature discharged from the compressor 14 and detected by the discharge temperature sensor 20 and the outflow temperature flowing out of the water refrigerant heat exchanger 15 A temperature difference from the refrigerant outflow temperature detected by the sensor 21 is used.

図２に示すように、このものでは、電子膨張弁１６開度を変化させると、圧縮機１４から吐出される冷媒の吐出温度および水冷媒熱交換器１５から流出する冷媒の流出温度の双方が変化するので、図２中の太実線で示されるように電子膨張弁１６の開度変化１パルス当たりの温度変化量が大きく、吐出温度と流出温度との温度差を所定の目標温度差とするまでの制御速度が速く、制御性が良く、ヒートポンプ式加熱手段３をすばやく最大効率で運転させることができるものである。 As shown in FIG. 2, in this case, when the opening degree of the electronic expansion valve 16 is changed, both the discharge temperature of the refrigerant discharged from the compressor 14 and the outflow temperature of the refrigerant flowing out of the water refrigerant heat exchanger 15 are obtained. 2, the temperature change amount per pulse of the opening change of the electronic expansion valve 16 is large as shown by a thick solid line in FIG. 2, and the temperature difference between the discharge temperature and the outflow temperature is set as a predetermined target temperature difference. The control speed is fast, the controllability is good, and the heat pump heating means 3 can be operated quickly and with maximum efficiency.

このように、上述のような加熱制御手段２５による制御が行われながら、沸き上げ運転が進行していくと、貯湯タンク２の下部の水がヒートポンプ式加熱手段３へ循環され、貯湯タンク２の上部から目標沸き上げ温度に加熱された湯が積層状態に貯湯される。貯湯タンク２内に必要な湯量が沸き上げられたことを貯湯温度センサ１２で検出するか、ヒートポンプ式加熱手段３の入水温度センサ２３で検出する入水温度が沸き上げし難い所定の高温度以上を検出するか、あるいは電力料金単価の安い深夜時間帯が終了した時点で、貯湯制御手段１３は沸き上げ運転を停止するべく加熱制御手段２５に停止指示を出し、加熱制御手段２５は圧縮機１４と加熱循環ポンプ１９の運転を停止して、沸き上げ運転を終了する。 As described above, when the boiling operation proceeds while the control by the heating control means 25 as described above is performed, the water in the lower part of the hot water storage tank 2 is circulated to the heat pump heating means 3, and Hot water heated to the target boiling temperature from above is stored in a stacked state. The hot water storage temperature sensor 12 detects that the required amount of hot water has been boiled in the hot water storage tank 2, or the incoming water temperature detected by the incoming water temperature sensor 23 of the heat pump type heating means 3 exceeds a predetermined high temperature that is difficult to boil up. When the detection is completed or the midnight time period when the power unit price is low is over, the hot water storage control means 13 issues a stop instruction to the heating control means 25 to stop the boiling operation, and the heating control means 25 is connected to the compressor 14. The operation of the heating circulation pump 19 is stopped and the boiling operation is finished.

この沸き上げ運転の終了直前の沸き終い時においては、貯湯タンク２内の湯層と水層との間の混合層の湯水がヒートポンプ式加熱手段３へ流入し、このとき、水冷媒熱交換器１５の水側に流入する湯水の入水温度が徐々に上昇していくものである。 At the end of boiling just before the end of the boiling operation, the hot water in the mixed layer between the hot water layer and the water layer in the hot water storage tank 2 flows into the heat pump type heating means 3, and at this time, water / refrigerant heat exchange is performed. The incoming temperature of the hot water flowing into the water side of the vessel 15 gradually rises.

ここで、沸き終い時におけるヒートポンプサイクル１８の状態を図３を用いて説明するが、本実施形態での沸き上げ運転におけるヒートポンプサイクル１８の状態は、図３の鎖線で示した安定時の状態から実線で示した沸き終い時の状態となる。なお、図３中に点線で描かれているのは、図５で示した従来の沸き終い時のヒートポンプサイクル１８の状態であり、本実施形態の沸き終い時のヒートポンプサイクル１８の状態との比較のためのものである。本実施形態では、吐出温度センサ２０の検出する冷媒温度と流出温度センサ２１の検出する冷媒温度との温度差ΔＨが所定の目標温度差ΔＨｍとなるように電子膨張弁１６の開度を制御するため、水冷媒熱交換器１５の水側に流入する湯水の入水温度が高くなっても、それに応じて最適な目標温度差ΔＨｍを算出することができ、温度差ΔＨを算出した最適な目標温度差ΔＨｍに保つので、沸き上げ運転中、特に、水冷媒熱交換器１５の水側に流入する入水温度が高くなる沸き終い時においても、運転効率が最大となる比エンタルピー差を保ちながらヒートポンプ式加熱手段３を運転させることができるものである。 Here, the state of the heat pump cycle 18 at the end of boiling will be described with reference to FIG. 3, but the state of the heat pump cycle 18 in the boiling operation in the present embodiment is the state at the time of stability shown by the chain line in FIG. To the state at the end of boiling shown by the solid line. In addition, what is drawn with a dotted line in FIG. 3 is the state of the heat pump cycle 18 at the end of boiling shown in FIG. 5, and the state of the heat pump cycle 18 at the end of boiling in this embodiment. For comparison. In the present embodiment, the opening degree of the electronic expansion valve 16 is controlled so that the temperature difference ΔH between the refrigerant temperature detected by the discharge temperature sensor 20 and the refrigerant temperature detected by the outflow temperature sensor 21 becomes a predetermined target temperature difference ΔHm. Therefore, even if the incoming temperature of the hot water flowing into the water side of the water-refrigerant heat exchanger 15 increases, the optimum target temperature difference ΔHm can be calculated accordingly, and the optimum target temperature calculated from the temperature difference ΔH can be calculated. Since the difference ΔHm is maintained, the heat pump maintains the specific enthalpy difference that maximizes the operation efficiency even during boiling operation, particularly at the end of boiling when the incoming water temperature flowing into the water side of the water refrigerant heat exchanger 15 becomes high. The type heating means 3 can be operated.

なお、本発明はこれまで説明してきた一実施形態に限定されることなく、その趣旨を変更しない範囲で適用可能なもので、例えば、ヒートポンプサイクル１８は減圧器としてエジェクターを用いたエジェクターサイクルでもよいものである。 The present invention is not limited to the embodiment described so far, and can be applied without changing the gist thereof. For example, the heat pump cycle 18 may be an ejector cycle using an ejector as a decompressor. Is.

また、ヒートポンプサイクル１８は、図４に示すように、水冷媒熱交換器１５を通過した後の高圧冷媒と圧縮機１４の吸入側の低圧冷媒との間で熱交換を行う内部熱交換器２６を備えた構成としてもよいものであり、この場合、流出温度センサ２１は、水冷媒熱交換器１５より下流側で、高圧冷媒が通過する内部熱交換器２６より上流側の冷媒温度を検出する位置に配設し、吐出温度センサ２０の検出する冷媒温度と流出温度センサ２１の検出する冷媒温度との温度差ΔＨが所定の目標温度差ΔＨｍとなるように電子膨張弁１６の開度を制御することで、先に説明した一実施形態と同様、運転効率が最大となる比エンタルピー差を保ちながらヒートポンプ式加熱手段３を運転させることができるものである。 In addition, as shown in FIG. 4, the heat pump cycle 18 includes an internal heat exchanger 26 that performs heat exchange between the high-pressure refrigerant after passing through the water-refrigerant heat exchanger 15 and the low-pressure refrigerant on the suction side of the compressor 14. In this case, the outflow temperature sensor 21 detects the refrigerant temperature downstream of the water refrigerant heat exchanger 15 and upstream of the internal heat exchanger 26 through which the high-pressure refrigerant passes. The opening of the electronic expansion valve 16 is controlled so that the temperature difference ΔH between the refrigerant temperature detected by the discharge temperature sensor 20 and the refrigerant temperature detected by the outflow temperature sensor 21 becomes a predetermined target temperature difference ΔHm. By doing so, the heat pump heating means 3 can be operated while maintaining the specific enthalpy difference that maximizes the operating efficiency, as in the embodiment described above.

２貯湯タンク
３ヒートポンプ式加熱手段
４加熱循環回路
１４圧縮機
１５水冷媒熱交換器
１６電子膨張弁（減圧器）
１７空気熱交換器（蒸発器）
２０吐出温度センサ
２１流出温度センサ
２２外気温度センサ
２３入水温度センサ
２５加熱制御手段（制御手段） 2 Hot water storage tank 3 Heat pump type heating means 4 Heating circulation circuit 14 Compressor 15 Water refrigerant heat exchanger 16 Electronic expansion valve (pressure reducer)
17 Air heat exchanger (evaporator)
20 Discharge temperature sensor 21 Outflow temperature sensor 22 Outside air temperature sensor 23 Incoming water temperature sensor 25 Heating control means (control means)

Claims

湯水を貯湯する貯湯タンクと、圧縮機、水冷媒熱交換器、減圧器、蒸発器を備えたヒートポンプ式加熱手段と、該ヒートポンプ式加熱手段の前記水冷媒熱交換器の水側と前記貯湯タンクとを環状に接続する加熱循環回路と、前記貯湯タンク内の湯水を目標沸き上げ温度に加熱するよう前記ヒートポンプ式加熱手段を制御する制御手段とを備えたヒートポンプ式給湯装置において、前記制御手段は、前記圧縮機から吐出される冷媒の吐出温度と前記水冷媒熱交換器から流出する冷媒の流出温度との温度差が、所定の目標温度差となるように前記減圧器の開度を制御し、前記所定の目標温度差は、前記目標沸き上げ温度と外気温度と前記水冷媒熱交換器に流入する湯水の入水温度とに基づいて算出するようにしたことを特徴とするヒートポンプ式給湯装置。 A hot water storage tank for storing hot water, a heat pump heating means including a compressor, a water refrigerant heat exchanger, a decompressor, and an evaporator, a water side of the water refrigerant heat exchanger of the heat pump heating means, and the hot water storage tank In the heat pump type hot water supply apparatus, the control means includes: a heating circulation circuit that connects the ring shape and a control means for controlling the heat pump heating means to heat the hot water in the hot water storage tank to a target boiling temperature. , the temperature difference between the outlet temperature of the refrigerant flowing out from the water refrigerant heat exchanger and the discharge temperature of the refrigerant discharged from the compressor, and controlling the opening of said decompressor so that a predetermined target temperature difference , the predetermined target temperature difference, heat pump, characterized in that to calculate on the basis of the hot water in the incoming water temperature flowing into the water-refrigerant heat exchanger and the target boiling temperature and outside air temperature Hot water system.

湯水を貯湯する貯湯タンクと、圧縮機、水冷媒熱交換器、減圧器、蒸発器を備えたヒートポンプ式加熱手段と、該ヒートポンプ式加熱手段の前記水冷媒熱交換器の水側と前記貯湯タンクとを環状に接続する加熱循環回路と、前記貯湯タンク内の湯水を目標沸き上げ温度に加熱するよう前記ヒートポンプ式加熱手段を制御する制御手段とを備えたヒートポンプ式給湯装置において、前記制御手段は、前記圧縮機から吐出される冷媒の吐出温度と前記水冷媒熱交換器から流出する冷媒の流出温度との温度差が、所定の目標温度差となるように前記減圧器の開度を制御し、前記所定の目標温度差は、前記目標沸き上げ温度と外気温度と前記水冷媒熱交換器に流入する湯水の入水温度とに基づいて、前記外気温度が高くなる程、前記所定の目標温度差の値が小さくなり、前記入水温度が高くなる程、前記所定の目標温度差の値が小さくなり、前記目標沸き上げ温度が高くなる程、前記所定の目標温度差の値が大きくなるように算出するようにしたことを特徴とするヒートポンプ式給湯装置。 A hot water storage tank for storing hot water, a heat pump heating means including a compressor, a water refrigerant heat exchanger, a decompressor, and an evaporator, a water side of the water refrigerant heat exchanger of the heat pump heating means, and the hot water storage tank In the heat pump type hot water supply apparatus, the control means includes: a heating circulation circuit that connects the ring shape and a control means for controlling the heat pump heating means to heat the hot water in the hot water storage tank to a target boiling temperature. The opening degree of the decompressor is controlled so that the temperature difference between the discharge temperature of the refrigerant discharged from the compressor and the outflow temperature of the refrigerant flowing out of the water refrigerant heat exchanger becomes a predetermined target temperature difference. , the predetermined target temperature difference, based on the hot water of the incoming water temperature flowing into the water-refrigerant heat exchanger and the target boiling temperature and the outside air temperature, the higher the outside air temperature is high, the predetermined target temperature difference Value decreases, as the entering-water temperature increases, the value of the predetermined target temperature difference becomes smaller, the larger the target boiling temperature is higher, calculated as the value of the predetermined target temperature difference increases A heat pump type hot water supply device characterized in that it is configured to do so.