JP3738672B2 - Heat pump water heater - Google Patents

Heat pump water heater Download PDF

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Publication number
JP3738672B2
JP3738672B2 JP2000184698A JP2000184698A JP3738672B2 JP 3738672 B2 JP3738672 B2 JP 3738672B2 JP 2000184698 A JP2000184698 A JP 2000184698A JP 2000184698 A JP2000184698 A JP 2000184698A JP 3738672 B2 JP3738672 B2 JP 3738672B2
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Prior art keywords
refrigerant
heat pump
heat exchanger
compressor
cycle
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Expired - Fee Related
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JP2002005515A (en
Inventor
申也 野呂
久介 榊原
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Denso Corp
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Denso Corp
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2309/00—Gas cycle refrigeration machines
    • F25B2309/06—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide
    • F25B2309/061—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide with cycle highest pressure above the supercritical pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2339/00—Details of evaporators; Details of condensers
    • F25B2339/04—Details of condensers
    • F25B2339/047—Water-cooled condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2341/00—Details of ejectors not being used as compression device; Details of flow restrictors or expansion valves
    • F25B2341/06—Details of flow restrictors or expansion valves
    • F25B2341/063—Feed forward expansion valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
    • F25B9/008—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant the refrigerant being carbon dioxide

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  • Heat-Pump Type And Storage Water Heaters (AREA)

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給湯用流体の加熱手段として使用するヒートポンプ式給湯器に関する。
【０００２】
【従来の技術】
従来より、高圧側圧力が冷媒の臨界点を超えて作動する超臨界ヒートポンプサイクルを用いた給湯器が公知である。ヒートポンプサイクルは、図１に示すように、圧縮機６で加圧された高温冷媒を熱源として給湯水を加熱する水熱交換器７を有し、この水熱交換器７に流入する給湯水と水熱交換器７から流出する冷媒との温度差に基づいて高圧制御が行われている。
【０００３】
【発明が解決しようとする課題】
ところで、上記のヒートポンプサイクルは、図２に示すように、圧縮機６に吸引されるガス冷媒の過熱度を大きくすると、水熱交換器７の放熱能力が大きくなる（Ｑ→Ｑ′）。また、ガス冷媒の過熱度を大きくすると、圧縮機６の圧縮効率が低下して圧縮仕事も大きくなる（Ｌ→Ｌ′）。しかし、年間の外気温度が低い時期（冬季）と高い時期（夏季）とでは、外気温度が高い時期の方がサイクル内の低圧圧力（空気熱交換器９の蒸発圧力）が高くなるため、外気温度が低い時期より圧縮機６の圧縮仕事の増加が少なくなる。
【０００４】
従って、外気温度が高い時期には、圧縮機６に吸引されるガス冷媒にある程度の過熱度を持たせた方が、高効率にサイクル制御を行うことが可能である。
ところが、従来のヒートポンプサイクルは、アキュムレータ１０に余剰冷媒を貯留しているので、外気温度の変化に係わらず、圧縮機６に吸引されるガス冷媒の過熱度はゼロである。
本発明は、上記事情に基づいて成されたもので、その目的は、年間の外気温度が高い時期において、効率の高いサイクル制御を実行できるヒートポンプ式給湯器を提供することにある。
【０００５】
【課題を解決するための手段】
（請求項１の手段）
本発明のヒートポンプサイクルは、高圧側熱交換器の下流に弁開度を調節可能な膨張弁を具備し、この膨張弁の開度を変化させて高圧制御を行うことを特徴とする。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。
また、圧縮機に吸引される冷媒が、年間で外気温度が低い時期には乾燥飽和蒸気となり、且つ年間で外気温度が高い時期には過熱蒸気となる様に、サイクル内への冷媒封入量が決定されている。
この場合、外気温度が高い時期には、圧縮機に吸引される冷媒がある程度の過熱度を持つことにより、過熱度を持たない場合（過熱度＝０）と比較して、高圧側熱交換器の能力を圧縮機の仕事量（圧縮仕事）で除算して求められるサイクル効率が向上する。
【０００７】
（請求項２の手段）
請求項１に記載したヒートポンプ式給湯器において、
ヒートポンプサイクルは、目標の給湯能力が得られるように圧縮機の回転数を可変することを特徴とする。
例えば、膨張弁の開度を大きくすると、高圧側の冷媒圧力が低下して冷媒温度が低下するため、高圧側熱交換器での熱交換量が低下して給湯能力が低下する。この場合、圧縮機の回転数を大きくして高圧側熱交換器を流れる冷媒流量を増加させることにより、目標の給湯能力を確保することができる。
【０００８】
【発明の実施の形態】
次に、本発明のヒートポンプ式給湯器を図面に基づいて説明する。
図１はヒートポンプ式給湯器の構成を示す模式図、図２はＣＯ2 サイクルのＰ−Ｈ線図である。
本実施例のヒートポンプ式給湯器１は、加熱された給湯用水をタンク２内に貯留しておき、使用時にタンク２内から取り出した給湯用水を温度調節して使用者に供給するシステムであり、図１に示すように、給湯用水を貯留するタンク２、このタンク２に接続される温水回路３、給湯用水の加熱手段であるヒートポンプサイクル（下述する）、及び給湯器１の作動を制御する制御装置４等を具備している。
【０００９】
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、高温の給湯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内に貯留される給湯用水は、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。
温水回路３は、タンク２とヒートポンプサイクルの水熱交換器７とを環状に接続して設けられ、この温水回路３にタンク２内の給湯用水を流通させるウォータポンプ５が介在されている。ウォータポンプ５は、内蔵するモータの回転数を可変して循環水量を調節することができる。
【００１０】
ヒートポンプサイクルは、高圧側の冷媒圧力が臨界圧力以上となるサイクルで、図１に示すように、圧縮機６、上記の水熱交換器７（本発明の高圧側熱交換器）、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、冷媒として臨界圧力の低い二酸化炭素（ＣＯ2 ）を使用している。
圧縮機６は、内蔵する電動モータ（図示しない）によって駆動され、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７は、圧縮機６より吐出された高圧のガス冷媒と給湯用水とを熱交換するもので、図１に矢印で示すように、冷媒の流れ方向と給湯用水の流れ方向とが対向するように構成されている。
【００１１】
膨張弁８は、弁開度を電気的に調節可能な構造を有し、水熱交換器７で冷却された冷媒を弁開度に応じて減圧する。
空気熱交換器９は、ファン１１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と圧縮機６との間に介在されてサイクル内の余剰冷媒を蓄え、気相冷媒のみを圧縮機６に吸引させる。
【００１２】
ヒートポンプサイクルは、水熱交換器７に流入する給湯用水の温度を検出する水温センサ１２、水熱交換器７より流出する冷媒の温度を検出する冷媒温度センサ１３等を具備し、各センサ１２、１３の検出信号が制御装置４に入力される。制御装置４は、水温センサ１２及び冷媒温度センサ１３の検出信号から、水熱交換器７に流入する給湯用水と水熱交換器７より流出する冷媒との温度差ΔＴを求め、この温度差ΔＴに基づいてサイクル内の高圧圧力を制御している。具体的には、温度差ΔＴが目標値（例えば１０℃）となるように、膨張弁８の弁開度を電気的に制御し、且つ目標の給湯能力が得られるように、圧縮機６の回転数を制御している。
【００１３】
上記のヒートポンプサイクルは、図２に示すように、圧縮機６に吸引されるガス冷媒の過熱度ＳＨが大きくなると、圧縮機６の圧縮仕事が増加し（Ｌ→Ｌ′）、それに伴って水熱交換器７の放熱能力も大きくなる（Ｑ→Ｑ′）。しかし、年間で外気温度が低い時期（冬季）と高い時期（夏季）とでは、外気温度が高い時期の方がサイクル内の低圧圧力（空気熱交換器９の蒸発圧力）が高くなるため、外気温度が低い時期より圧縮機６の圧縮仕事の増加が少なくなる。
従って、外気温度が高い時期には、圧縮機６に吸引されるガス冷媒にある程度の過熱度を持たせた方が、システム効率を向上できる。
【００１４】
そこで、本実施例では、より高いシステム効率を実現するために、高温度条件下（例えば２５．６℃）において、圧縮機６に吸引されるガス冷媒がある程度の過熱度を持つ（過熱蒸気となる）様に制御されている。具体的には、低温度条件下（例えば３．０℃）において、前記の温度差ΔＴに基づいて高圧圧力が適切に制御されている状態で、圧縮機６に吸引されるガス冷媒が乾燥飽和蒸気（図２に示す飽和蒸気線上の冷媒）となる様に、サイクル内への冷媒封入量が決定されている。この場合、アキュムレータ１０内には、殆ど液冷媒が存在せず、且つ空気熱交換器９で蒸発した冷媒が過熱度を持たない乾燥飽和蒸気（ＳＨ＝０）となる。
この冷媒量は、ヒートポンプサイクルの容積、水熱交換器７の放熱能力、空気熱交換器９の吸熱能力、温度差ΔＴに基づいて制御される最適な高圧圧力等から計算でき、最終的には実機での試験により決定される。
【００１５】
（本実施例の効果）
本実施例のヒートポンプサイクルは、低温度条件下（冬季）において、圧縮機６に吸引されるガス冷媒が乾燥飽和蒸気となるため、高温度条件下（夏季）においては、高圧圧力が適切に制御されることにより、圧縮機６に吸引されるガス冷媒が過熱蒸気（過熱度を持つ飽和蒸気）となる。つまり、高温度条件下では、低圧側のバランス圧力が外気温度の低い冬季より高くなるため、冷媒密度が大きくなる。そのため、高温度条件下では、ＳＨ＝０となるための冷媒存在量が低温度条件下よりも多くなり、必然的に圧縮機６に吸引されるガス冷媒が過熱度を持つことになる。
これにより、圧縮機６に吸引されるガス冷媒の過熱度を、外気温度の変化に応じて制御することができ、特に外気温度の高い夏季では、水熱交換器７の放熱能力が増加し、且つ圧縮機６の仕事量（圧縮仕事）の増加分を小さく抑えることができるので、従来（ＳＨ＝０の場合）より高効率な給湯システムを実現できる。
【００１６】
（変形例）
上記の実施例では、温度差ΔＴ（水熱交換器７に流入する給湯用水と水熱交換器７より流出する冷媒との温度差）に基づいて膨張弁８の弁開度を制御しているが、目標の温度差ΔＴを得るために、ウォータポンプ５の吐出量を制御して水熱交換器７を流れる給湯用水の流量を変化させても良い。
【図面の簡単な説明】
【図１】ヒートポンプ式給湯器の構成を示す模式図である。
【図２】ＣＯ2 サイクルのＰ−Ｈ線図である。
【符号の説明】
１ ヒートポンプ式給湯器
２ タンク
６ 圧縮機
７ 水熱交換器（高圧側熱交換器）
８ 膨張弁
１０ アキュムレータ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat pump water heater that uses a supercritical heat pump cycle as a heating means for a hot water supply fluid.
[0002]
[Prior art]
Conventionally, a water heater using a supercritical heat pump cycle in which the high-pressure side pressure operates beyond the critical point of the refrigerant is known. As shown in FIG. 1, the heat pump cycle includes a water heat exchanger 7 that heats hot water using the high-temperature refrigerant pressurized by the compressor 6 as a heat source, and hot water that flows into the water heat exchanger 7. High pressure control is performed based on the temperature difference from the refrigerant flowing out of the water heat exchanger 7.
[0003]
[Problems to be solved by the invention]
In the above heat pump cycle, as shown in FIG. 2, when the degree of superheat of the gas refrigerant sucked into the compressor 6 is increased, the heat radiation capacity of the water heat exchanger 7 is increased (Q → Q ′). Moreover, if the superheat degree of a gas refrigerant is enlarged, the compression efficiency of the compressor 6 will fall and compression work will also become large (L-> L '). However, when the outdoor temperature is low (winter) and high (summer) during the year, the low pressure (evaporation pressure of the air heat exchanger 9) in the cycle is higher when the outdoor temperature is high. The increase in the compression work of the compressor 6 is less than when the temperature is low.
[0004]
Therefore, when the outside air temperature is high, it is possible to perform cycle control with high efficiency by giving the gas refrigerant sucked into the compressor 6 a certain degree of superheat.
However, in the conventional heat pump cycle, since the surplus refrigerant is stored in the accumulator 10, the superheat degree of the gas refrigerant sucked into the compressor 6 is zero regardless of the change in the outside air temperature.
The present invention has been made based on the above circumstances, and an object of the present invention is to provide a heat pump type water heater capable of performing cycle control with high efficiency at a time when the annual outside air temperature is high.
[0005]
[Means for Solving the Problems]
(Means of Claim 1)
The heat pump cycle of the present invention is characterized in that an expansion valve capable of adjusting the valve opening is provided downstream of the high pressure side heat exchanger, and high pressure control is performed by changing the opening of the expansion valve. 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.
In addition, the amount of refrigerant enclosed in the cycle is such that the refrigerant sucked into the compressor becomes dry saturated steam when the outside air temperature is low throughout the year and becomes superheated steam when the outside air temperature is high throughout the year. It has been decided.
In this case, when the outside air temperature is high, the refrigerant sucked into the compressor has a certain degree of superheat, so that the high pressure side heat exchanger is compared with a case where the refrigerant does not have a degree of superheat (superheat degree = 0). Is divided by the amount of work of the compressor (compression work) to improve the cycle efficiency.
[0007]
(Means of Claim 2 )
In the heat pump type water heater according to claim 1 ,
The heat pump cycle is characterized in that the number of rotations of the compressor is varied so as to obtain a target hot water supply capacity.
For example, if the opening degree of the expansion valve is increased, the refrigerant pressure on the high pressure side is reduced and the refrigerant temperature is lowered, so that the heat exchange amount in the high pressure side heat exchanger is reduced and the hot water supply capability is reduced. In this case, the target hot-water supply capability can be ensured by increasing the number of revolutions of the compressor and increasing the flow rate of the refrigerant flowing through the high-pressure side heat exchanger.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, the heat pump type water heater of the present invention will be described based on the drawings.
FIG. 1 is a schematic diagram showing the configuration of a heat pump type water heater, and FIG. 2 is a PH diagram of a CO 2 cycle.
The heat pump type hot water heater 1 of the present embodiment is a system that stores heated hot water supply water in the tank 2 and adjusts the temperature of the hot water supply water taken out from the tank 2 during use and supplies it to the user. As shown in FIG. 1, a tank 2 for storing hot water supply water, a hot water circuit 3 connected to the tank 2, a heat pump cycle (described below) that is a heating means for hot water supply, and the operation of the water heater 1 are controlled. A control device 4 and the like are provided.
[0009]
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 hot water for a long time. The hot water supply water stored in the tank 2 may be used directly in a kitchen, a bath, or the like, but can also be used as a heat source other than for hot water supply, for example, for floor heating or indoor air conditioning.
The hot water circuit 3 is provided by annularly connecting a tank 2 and a water heat exchanger 7 of a heat pump cycle, and a water pump 5 for circulating hot water in the tank 2 is interposed in the hot water circuit 3. The water pump 5 can adjust the amount of circulating water by changing the number of rotations of a built-in motor.
[0010]
The heat pump cycle is a cycle in which the refrigerant pressure on the high pressure side becomes equal to or higher than the critical pressure. As shown in FIG. 1, the compressor 6, the above-described water heat exchanger 7 (the high pressure side heat exchanger of the present invention), and the expansion valve 8 The air heat exchanger 9 and the accumulator 10 are used, and carbon dioxide (CO 2 ) having a low critical pressure is used as a refrigerant.
The compressor 6 is driven by a built-in electric motor (not shown), and compresses and sucks the sucked gas refrigerant to a critical pressure or higher.
The water heat exchanger 7 exchanges heat between the high-pressure gas refrigerant discharged from the compressor 6 and the hot water supply water, and the flow direction of the refrigerant and the flow direction of the hot water supply water are indicated by arrows in FIG. It is comprised so that it may oppose.
[0011]
The expansion valve 8 has a structure in which the valve opening degree can be electrically adjusted, and depressurizes the refrigerant cooled by the water heat exchanger 7 according to the valve opening degree.
The air heat exchanger 9 receives the air blown by the fan 11 and evaporates the refrigerant decompressed by the expansion valve 8 by heat exchange with the outside air.
The accumulator 10 is interposed between the air heat exchanger 9 and the compressor 6, stores excess refrigerant in the cycle, and causes the compressor 6 to suck only the gas-phase refrigerant.
[0012]
The heat pump cycle includes a water temperature sensor 12 for detecting the temperature of hot water supply water flowing into the water heat exchanger 7, a refrigerant temperature sensor 13 for detecting the temperature of refrigerant flowing out of the water heat exchanger 7, and the like. Thirteen detection signals are input to the control device 4. The control device 4 obtains a temperature difference ΔT between the hot water supply water flowing into the water heat exchanger 7 and the refrigerant flowing out of the water heat exchanger 7 from detection signals of the water temperature sensor 12 and the refrigerant temperature sensor 13, and this temperature difference ΔT. Based on the above, the high pressure in the cycle is controlled. Specifically, the valve opening of the expansion valve 8 is electrically controlled so that the temperature difference ΔT becomes a target value (for example, 10 ° C.), and the target hot water supply capacity is obtained. The number of revolutions is controlled.
[0013]
In the above heat pump cycle, as shown in FIG. 2, when the superheat degree SH of the gas refrigerant sucked into the compressor 6 increases, the compression work of the compressor 6 increases (L → L ′), and accordingly, The heat dissipation capacity of the heat exchanger 7 is also increased (Q → Q ′). However, when the outdoor air temperature is low (winter) and high (summer) during the year, the low pressure (evaporation pressure of the air heat exchanger 9) in the cycle is higher when the outdoor temperature is high. The increase in the compression work of the compressor 6 is less than when the temperature is low.
Therefore, when the outside air temperature is high, the system efficiency can be improved by giving the gas refrigerant sucked into the compressor 6 a certain degree of superheat.
[0014]
Therefore, in the present embodiment, in order to achieve higher system efficiency, the gas refrigerant sucked into the compressor 6 has a certain degree of superheat (superheated steam and the like) under high temperature conditions (for example, 25.6 ° C.). Is controlled). Specifically, the gas refrigerant sucked into the compressor 6 is dry saturated under a low temperature condition (for example, 3.0 ° C.) in a state where the high pressure is appropriately controlled based on the temperature difference ΔT. The amount of refrigerant enclosed in the cycle is determined so as to be steam (refrigerant on the saturated vapor line shown in FIG. 2). In this case, almost no liquid refrigerant exists in the accumulator 10, and the refrigerant evaporated in the air heat exchanger 9 becomes dry saturated steam (SH = 0) having no superheat degree.
This amount of refrigerant can be calculated from the volume of the heat pump cycle, the heat dissipation capacity of the water heat exchanger 7, the heat absorption capacity of the air heat exchanger 9, the optimal high pressure controlled based on the temperature difference ΔT, etc. Determined by testing with actual equipment.
[0015]
(Effect of this embodiment)
In the heat pump cycle of the present embodiment, the gas refrigerant sucked into the compressor 6 becomes dry saturated vapor under a low temperature condition (winter), so that the high pressure is appropriately controlled under a high temperature condition (summer). As a result, the gas refrigerant sucked into the compressor 6 becomes superheated steam (saturated steam having superheat degree). That is, under high temperature conditions, the balance pressure on the low pressure side is higher than in winter when the outside air temperature is low, and the refrigerant density increases. Therefore, under a high temperature condition, the refrigerant abundance for achieving SH = 0 is greater than under a low temperature condition, and the gas refrigerant sucked into the compressor 6 inevitably has a superheat degree.
Thereby, the superheat degree of the gas refrigerant sucked into the compressor 6 can be controlled according to a change in the outside air temperature, and particularly in the summer when the outside air temperature is high, the heat radiation capacity of the water heat exchanger 7 is increased. In addition, since the increase in the work amount (compression work) of the compressor 6 can be kept small, a hot water supply system that is more efficient than the conventional case (when SH = 0) can be realized.
[0016]
(Modification)
In the above embodiment, the valve opening degree of the expansion valve 8 is controlled based on the temperature difference ΔT (temperature difference between the hot water supply water flowing into the water heat exchanger 7 and the refrigerant flowing out of the water heat exchanger 7). However, in order to obtain the target temperature difference ΔT, the discharge amount of the water pump 5 may be controlled to change the flow rate of the hot water supply water flowing through the water heat exchanger 7.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a configuration of a heat pump type water heater.
FIG. 2 is a PH diagram of a CO 2 cycle.
[Explanation of symbols]
1 Heat pump type water heater 2 Tank 6 Compressor 7 Water heat exchanger (high pressure side heat exchanger)
8 Expansion valve 10 Accumulator

Claims (2)

サイクル内の余剰冷媒を貯留するアキュムレータと、
このアキュムレータより吸引した気相冷媒を臨界圧力以上に加圧して吐出する圧縮機と、
この圧縮機で加圧された冷媒と給湯用の流体とを対向流として熱交換させる高圧側熱交換器とを有し、
前記高圧側熱交換器に流入する流体と前記高圧側熱交換器より流出する冷媒との温度差に基づいて高圧制御を行うヒートポンプサイクルを備え、
前記高圧側熱交換器で冷媒との熱交換により加熱された流体をタンク内に貯留して給湯等に使用するヒートポンプ式給湯器であって、
前記ヒートポンプサイクルは、前記高圧側熱交換器の下流に弁開度を調節可能な膨張弁を具備し、この膨張弁の開度を変化させて高圧制御を行い、且つ前記圧縮機に吸引される冷媒が、年間で外気温度が低い時期には乾燥飽和蒸気となり、且つ年間で外気温度が高い時期には過熱蒸気となる様に、サイクル内への冷媒封入量が決定されていることを特徴とするヒートポンプ式給湯器。An accumulator for storing excess refrigerant in the cycle;
A compressor that pressurizes and discharges the gas-phase refrigerant sucked from the accumulator above a critical pressure;
A pressurized fluid for refrigerant and hot water possess the high-pressure side heat exchanger for exchanging heat as counterflow in this compressor,
A heat pump cycle that performs high pressure control based on a temperature difference between the fluid flowing into the high pressure side heat exchanger and the refrigerant flowing out of the high pressure side heat exchanger;
A heat pump type water heater for storing a fluid heated by heat exchange with a refrigerant in the high-pressure side heat exchanger and using it for hot water supply or the like in a tank,
The heat pump cycle includes an expansion valve whose valve opening degree can be adjusted downstream of the high pressure side heat exchanger, performs high pressure control by changing the opening degree of the expansion valve, and is sucked into the compressor. It is characterized in that the amount of refrigerant enclosed in the cycle is determined so that the refrigerant becomes dry saturated steam when the outdoor temperature is low during the year and becomes superheated steam when the outdoor temperature is high during the year. A heat pump type water heater. 請求項１に記載したヒートポンプ式給湯器において、
前記ヒートポンプサイクルは、目標の給湯能力が得られるように前記圧縮機の回転数を可変することを特徴とするヒートポンプ式給湯器。In the heat pump type water heater according to claim 1 ,
In the heat pump cycle, the number of rotations of the compressor is varied so as to obtain a target hot water supply capacity.
JP2000184698A 2000-06-20 2000-06-20 Heat pump water heater Expired - Fee Related JP3738672B2 (en)

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