JP4258219B2

JP4258219B2 - Refrigeration cycle equipment

Info

Publication number: JP4258219B2
Application number: JP2003027582A
Authority: JP
Inventors: 宏治吉武; 久介榊原; 忠幸百瀬; 丈二黒木
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2003-02-04
Filing date: 2003-02-04
Publication date: 2009-04-30
Anticipated expiration: 2023-02-04
Also published as: JP2004239481A

Description

【０００１】
【発明の属する技術分野】
本発明は、高圧側冷媒圧力を検出して冷凍サイクルの成績係数が最大付近となる高圧側冷媒圧力範囲に制御する冷凍サイクル装置に関するものであり、特に圧力検出手段の検出値の補正に関する。
【０００２】
【従来の技術】
高圧側冷媒圧力を制御する従来技術として、特許文献１に示すものがある。高圧側が超臨界圧力にて運転される冷媒を用いた冷凍サイクル装置において、高圧側熱交換器の出口配管温度を検知し、その出口配管温度と冷凍サイクルの成績係数が最大付近となる高圧圧力範囲との関係を基にして、電子式膨張弁の開度、圧縮機の回転数、室内あるいは室外ファンの回転数のうち少なくとも１つ以上の制御を行っている。
【０００３】
【特許文献１】
特開２００２−１３０７７０号公報
【０００４】
【発明が解決しようとする課題】
上記従来技術のような配管温度から高圧側冷媒圧力を推定する方法は、冷凍サイクルの状態が安定している安定期では良いが、不安定な過渡期では高圧側冷媒圧力の推定値が振れて作動が不安定になるという問題がある。そこで、高圧側冷媒回路に圧力センサを設けて実際の圧力を検知することが必要となってくる。
【０００５】
しかし、コストを考慮して比較的精度の低い圧力センサや製造上のばらつきの大きな圧力センサを用いる場合、冷凍サイクル装置毎に性能のばらつきが生じるという問題がある。本発明は、上記従来の問題に鑑みて成されたものであり、その目的は、高圧側の冷媒圧力を低コストで安定且つ精度良く検知することのできる冷凍サイクル装置を提供することにある。
【０００６】
【課題を解決するための手段】
上記目的を達成するために、下記の技術的手段を採用する。すなわち、請求項１に記載の発明では、少なくとも圧縮機（１）、高圧側熱交換器（２）、減圧手段（３）、および低圧側熱交換器（４）を液配管およびガス配管で接続して形成した冷凍サイクル（Ｒ）と、高圧側熱交換器（２）に対して被加熱媒体を供給する被加熱媒体供給手段（６）、および低圧側熱交換器（４）に対して被冷却媒体を供給する被冷却媒体供給手段（４ａ）と、圧縮機（１）が吐出する高圧側冷媒圧力を検出する高圧圧力検出手段（９）と、高圧圧力検出手段（９）の検出結果を基に減圧手段（３）の開度、圧縮機（１）の回転数、被加熱媒体の流量、および被冷却媒体の流量のうち少なくとも１つを制御して冷凍サイクル（Ｒ）の成績係数が最大付近となる高圧側冷媒圧力範囲に制御する制御手段（１２）と、制御手段（１２）に、内部に記憶保持した補正値マップの補正値を用いて高圧圧力検出手段（９）の検出値を補正する検出値補正部（１２ａ）と、圧縮機（１）が吸入する低圧側冷媒の温度を検出する吸入温度検出手段（１０）、および圧縮機（１）が吐出する高圧側冷媒の温度を検出する吐出温度検出手段（８）と、制御手段（１２）に、両温度検出手段（８、１０）の検出結果から圧縮機（１）が吐出する高圧側冷媒圧力の推定値を算出する推定値算出部（１２ｂ）とを備え、
制御手段（１２）は、高圧圧力検出手段（９）の検出値を取り込むと同時に両温度検出手段（８、１０）の検出結果から推定値を算出し、その推定値に対して検出値が所定値以上の差がある場合、その差をなくすべく補正値として検出値補正部（１２ａ）の補正値マップに記憶保持させることを特徴とする。
【０００９】
これにより、低コストで比較的精度の低い圧力センサや製造上のばらつきの大きな圧力センサを用いても、個々の圧力センサでの各圧力検出値と吸入・吐出温度を基にした理論上の推定値とのずれを、圧力検出値毎の補正値として蓄えることにより、冷凍サイクル装置毎に性能のばらつきが生じることなく、高圧側の冷媒圧力を安定且つ精度良く検知することができる。
【００１０】
請求項２に記載の発明では、冷凍サイクル装置の総稼動時間が所定時間以下の間、請求項１に記載の作動を行なうことを特徴とする。また、請求項３に記載の発明では、冷凍サイクル装置の総稼動時間が所定時間以下の間、高圧側冷媒圧力の制御には検出値を用いずに推定値を用いることを特徴とする。
【００１１】
このように、所定期間の間データを蓄積してから実行に移ることで、冷凍サイクル装置の作動を安定したものにすると共に、冷凍サイクル装置を保護することができる。尚、上記各手段に付した括弧内の符号は、後述する実施形態記載の具体的手段との対応関係を示すものである。
【００１２】
【発明の実施の形態】
以下、本発明の実施の形態を図に基づいて説明する。図１は、本発明の一実施形態における冷凍サイクル装置の構成を示す模式図である。尚、本実施形態は、冷凍サイクル装置をヒートポンプ式給湯器に適用したものである。本実施形態でのヒートポンプ式給湯器は、超臨界ヒートポンプサイクルを用いて給湯用水を高温（本実施形態では約９０℃）に加熱すると共に、その加熱した高温水を貯湯タンク７に貯湯すると共に、貯湯されていた高温水と給水される冷水と混合し、所望する温度の温水にして給湯している。
【００１３】
尚、超臨界ヒートポンプサイクル（以下、ヒートポンプと略す）とは、高圧側の冷媒圧力が冷媒の臨界圧力以上となるヒートポンプサイクルを言い、本実施形態では二酸化炭素（ＣＯ_２）を冷媒とするヒートポンプサイクルである。ヒートポンプ式給湯器は大きく分けて、主に後述する冷凍サイクル機器が収納されたヒートポンプシステムとしての冷凍サイクルユニットと、主に貯湯タンク７が収納されたタンクユニットとよりなる。
【００１４】
また、冷凍サイクルユニット内は、大きく分けてヒートポンプサイクルの冷媒回路（冷凍サイクル）Ｒと、給湯関係の給湯水加熱回路Ｋとで構成されている。まず、ヒートポンプサイクルの冷媒回路Ｒは、冷媒を圧縮する圧縮機１と、給湯用水の加熱手段である水冷媒熱交換器（高圧側熱交換器）２と、減圧手段である減圧弁３と、大気から吸熱するための冷媒空気熱交（低圧側熱交換器）換器４と、ヒートポンプサイクル中の余剰冷媒を蓄えると共に冷媒を気液分離してガス冷媒だけを圧縮機１へ供給するアキュームレータ５とを環状に接続して構成され、冷媒として臨界温度の低い二酸化炭素（ＣＯ_２）が封入されている。
【００１５】
圧縮機１は、内蔵する駆動モータと、吸引したガス冷媒を臨界圧力以上の高圧にまで昇圧して吐出する高圧圧縮部とで構成しており、これらが密閉容器内に収納されている。水冷媒熱交換器２は、高圧圧縮部で昇圧された高温高圧のガス冷媒と給湯用水とを熱交換して給湯用水を加熱するもので、高圧冷媒通路２ａに隣接して給湯水通路２ｂが設けられ、その高圧冷媒通路２ａを流れる冷媒の流れ方向と給湯水通路２ｂを流れる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。
【００１６】
減圧弁３は、水冷媒熱交換器２と室外熱交換器４との間に設けられ、水冷媒熱交換器２で冷却された冷媒を高圧から低圧まで減圧して室外熱交換器４に供給する。また、この減圧弁３は、弁開度を電気的に調整可能な構成を有し、後述する制御装置（制御手段）１２により通電制御される。室外熱交換器４は、送風ファン（被冷却媒体供給手段）４ａによる送風を受けて、減圧弁３で減圧された冷媒を大気との熱交換によって蒸発させ、ガスとなった冷媒は先の圧縮機１に吸引される。
【００１７】
次に、給湯関係の給湯水加熱回路Ｋは、給湯用水の加熱手段である上記水冷媒熱交換器２の給湯水通路３ｂと、給湯用水を循環させる循環ポンプ（被加熱媒体供給手段）６と、給湯用水を貯留する貯湯タンク７とを環状に接続して構成される。循環ポンプ６は、図示しない内蔵モータの回転数に応じて流水量を調節することができる。貯湯タンク７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。
【００１８】
そして、制御装置１２は、圧縮機１・膨張弁３・送風ファン４ａ・循環ポンプ６へ信号を送り、給湯水の沸き上げを開始する。圧縮機１にて高温・高圧に圧縮されたＣＯ_２冷媒と、水冷媒熱交換器２にて循環ポンプ６より圧送された水とが熱交換して温水が作られる。この後、ＣＯ_２冷媒は膨張弁３にて膨張して低温低圧となり、室外熱交換器４にて蒸発して大気より吸熱を行い、アキュームレータ５で気液分離されて圧縮機１へと戻る。
【００１９】
また、水冷媒熱交換器２で作られた温水は、貯湯タンク７に貯湯される。そして、貯湯タンク７に貯留された高温の給湯用水は、出湯時に図示しない温調用混合弁で水道からの冷水と混合して所定温度調節した後、主に台所や風呂等に給湯して使用される。
【００２０】
次に、本発明の要部に関する構成を説明する。圧縮機１の吐出側配管には、圧縮機１が吐出する高圧側冷媒温度を検出する吐出温度センサ（吐出温度検出手段）８が設けられ、水冷媒熱交換器２の冷媒出口には、高圧側冷媒圧力を検出する圧力センサ（高圧圧力検出手段）９が設けられ、室外熱交換器４の冷媒出口側配管には、圧縮機１が吸入する低圧側冷媒温度を検出する吸入温度センサ（吸入温度検出手段）１０が設けられている。
【００２１】
そして、これらセンサ８〜１０の検出値は制御装置１２に入力され、制御装置１２は各検出値に基づいて、圧縮機１の回転数、減圧弁３の開度、送風ファン４ａの回転数、循環ポンプ６の流量をそれぞれ制御する。また、制御装置１２には、内部に記憶保持した補正値マップの補正値を用いて圧力センサ９の検出値を補正する検出値補正部１２ａと、両温度センサ８・１０の検出結果から圧縮機１が吐出する高圧側冷媒圧力の推定値を算出する推定値算出部１２ｂとを設けている。
【００２２】
圧力センサ９の精度やばらつきから、真の圧力値に対して検出値がずれる場合がある。そこで、沸き上げ運転中に冷媒温度からの推定値を算出し、この推定値に対して検出値を比較し、所定以上の差がある場合、制御装置１２内に記憶保持している検出値の補正値マップに、その差が無くなるよう差分を補正値として上書きし、後に補正値として用いることにより、検出値を精度良く使うことができる。
【００２３】
そしてこれは、例えば、システムの試運転時等で補正値マップへの蓄積が無い場合は圧力センサ９の精度上、正確な高圧圧力検出が行なえない場合がある。そこで、冷凍サイクル装置を稼動し始めてから所定時間（例えば、1週間分の稼動時間）内に起動された沸き上げ運転に関しては、圧力センサ９の検出値を用いずに両温度センサ８・１０からの推定値を用いる。そして、この所定時間の間は、補正値マップへ補正値データの蓄積を行なうものである。
【００２４】
図２は、その補正値マップへの補正値データの蓄積手順を示すフローチャートである。まず、ステップＳ１で沸き上げ運転中か否かを判定する。その判定結果がＮＯであって沸き上げ運転以外の状態である場合には、リターンしてステップＳ１の判定を繰り返す。また、判定結果がＹＥＳであって沸き上げ運転の状態にある場合にはステップＳ２へ進む。
【００２５】
次に、ステップＳ２で冷凍サイクル装置の総稼動時間が所定時間以下か否かを判定する。その判定結果がＮＯであって所定時間を超えている場合には、以下の処理を行なわない。また、判定結果がＹＥＳであって所定時間以下の場合にはステップＳ３へ進んで以下の処理を行なう。
【００２６】
ステップＳ３で、高圧側冷媒圧力を圧力センサ９で検知して、その検出値を取り込む。また、ステップＳ４で、高圧側冷媒温度と低圧側冷媒温度とを両温度センサ８・１０で検知して、その検出値を取り込みと共に、推定値算出部１２ｂで両温度センサ８・１０の検出結果から圧縮機１が吐出する高圧側冷媒圧力の推定値を算出する。そして、ステップＳ５で、算出した推定値に対する圧力センサ９での検出値との差を算出する。
【００２７】
次のステップＳ６では、ステップＳ５で算出した差が所定値以上であるか否かを判定する。その判定結果がＮＯであって差が所定値以下である場合には、リターンして処理は行なわないが、判定結果がＹＥＳであって差が所定値以上である場合にはステップＳ７へ進み、算出した差をその時の検出値に対する補正値として検出値補正部１２ａの補正値マップに記憶保持させるものである。
【００２８】
次に、本実施形態での特徴を述べる。まず、制御装置１２に、内部に記憶保持した補正値マップの補正値を用いて圧力センサ９の検出値を補正する検出値補正部１２ａを設けている。これにより、低コストで比較的精度の低い圧力センサや製造上のばらつきの大きな圧力センサを用いても、冷凍サイクル装置毎に性能のばらつきが生じることなく、高圧側の冷媒圧力を安定且つ精度良く検知することができる。
【００２９】
また、冷凍サイクル装置に、圧縮機１が吸入する低圧側冷媒温度を検出する吸入温度センサ１０、および圧縮機１が吐出する高圧側冷媒温度を検出する吐出温度センサ８と、制御装置１２に、両温度センサ８・１０の検出結果から圧縮機１が吐出する高圧側冷媒圧力の推定値を算出する推定値算出部１２ｂとを設け、制御装置１２は、圧力センサ９の検出値を取り込むと同時に両温度センサ８・１０の検出結果から推定値を算出し、その推定値に対して検出値が所定値以上の差がある場合、その差を無くすべく補正値として検出値補正部１２ａの補正値マップに記憶保持させている。
【００３０】
これにより、低コストで比較的精度の低い圧力センサや製造上のばらつきの大きな圧力センサを用いても、個々の圧力センサでの各圧力検出値と吸入・吐出温度を基にした理論上の推定値とのずれを、圧力検出値毎の補正値として蓄えることにより、冷凍サイクル装置毎に性能のばらつきが生じることなく、高圧側の冷媒圧力を安定且つ精度良く検知することができる。
【００３１】
また、冷凍サイクル装置の総稼動時間が所定時間以下の間、上記の作動を行なうと共に、高圧側冷媒圧力の制御には検出値を用いずに推定値を用いている。このように、所定期間の間データを蓄積してから実行に移ることで、冷凍サイクル装置の作動を安定したものにすると共に、冷凍サイクル装置を保護することができる。
【００３２】
（その他の実施形態）
上述の実施形態では、圧縮機１が吸入する低圧側冷媒温度を検出する吸入温度検出手段として、室外熱交換器４の冷媒出口側配管に設けた吸入温度センサ１０を用いているが、温度センサ１１（図１参照）を用いて室外熱交換器４を通過した空気温度で代用検知しても良い。
【図面の簡単な説明】
【図１】本発明の一実施形態における冷凍サイクル装置の構成を示す模式図である。
【図２】補正値マップへの補正値データの蓄積手順を示すフローチャートである。
【符号の説明】
１圧縮機
２水冷媒熱交換器（高圧側熱交換器）
３膨張弁（減圧手段）
４室外熱交換器（低圧側熱交換器）
４ａ送風ファン（被冷却媒体供給手段）
６循環ポンプ（被加熱媒体供給手段）
８吐出温度センサ（吐出温度検出手段）
９圧力センサ（高圧圧力検出手段）
１０吸入温度センサ（吸入温度検出手段）
１２制御装置（制御手段）
１２ａ検出値補正部
１２ｂ推定値算出部
Ｒ冷凍サイクル[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigeration cycle apparatus that detects a high-pressure side refrigerant pressure and controls it to a high-pressure side refrigerant pressure range in which the coefficient of performance of the refrigeration cycle is near the maximum, and particularly relates to correction of a detection value of a pressure detection means.
[0002]
[Prior art]
As a prior art for controlling the high-pressure side refrigerant pressure, there is one shown in Patent Document 1. In a refrigeration cycle system using refrigerant whose high pressure side is operated at supercritical pressure, the outlet pipe temperature of the high pressure side heat exchanger is detected, and the outlet pipe temperature and the coefficient of performance of the refrigeration cycle are near the maximum. Based on the relationship, at least one of the opening degree of the electronic expansion valve, the rotational speed of the compressor, and the rotational speed of the indoor or outdoor fan is controlled.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-130770
[Problems to be solved by the invention]
The method for estimating the high-pressure side refrigerant pressure from the piping temperature as in the above prior art is good in the stable period when the state of the refrigeration cycle is stable, but the estimated value of the high-pressure side refrigerant pressure fluctuates in an unstable transition period. There is a problem that operation becomes unstable. Therefore, it is necessary to provide a pressure sensor in the high-pressure side refrigerant circuit to detect the actual pressure.
[0005]
However, when a pressure sensor with relatively low accuracy or a pressure sensor with a large manufacturing variation is used in consideration of cost, there is a problem that performance varies among refrigeration cycle apparatuses. The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a refrigeration cycle apparatus that can stably and accurately detect the refrigerant pressure on the high-pressure side at low cost.
[0006]
[Means for Solving the Problems]
To achieve the above object, employing the technical means described below. That is, in the invention described in claim 1, at least the compressor (1), the high pressure side heat exchanger (2), the pressure reducing means (3), and the low pressure side heat exchanger (4) are connected by liquid piping and gas piping. Refrigeration cycle (R) formed in this manner, heated medium supply means (6) for supplying a heated medium to the high pressure side heat exchanger (2), and to the low pressure side heat exchanger (4) The detection results of the cooling medium supply means (4a) for supplying the cooling medium, the high pressure detection means (9) for detecting the high pressure side refrigerant pressure discharged from the compressor (1), and the detection results of the high pressure detection means (9) are shown. The coefficient of performance of the refrigeration cycle (R) is controlled by controlling at least one of the opening of the decompression means (3), the rotational speed of the compressor (1), the flow rate of the heated medium, and the flow rate of the cooled medium. control means for controlling the high-pressure side refrigerant pressure range to be near the maximum (12), the control hand (12), low pressure detection value correcting unit for correcting the detection value of the high-pressure pressure detection means (9) using the correction value of the correction value map stored and held inside the (12a), the compressor (1) inhales The suction temperature detection means (10) for detecting the temperature of the side refrigerant, the discharge temperature detection means (8) for detecting the temperature of the high-pressure side refrigerant discharged from the compressor (1), and the control means (12) have both temperatures An estimated value calculation unit (12b) for calculating an estimated value of the high-pressure side refrigerant pressure discharged from the compressor (1) from the detection result of the detection means (8, 10),
The control means (12) takes in the detection value of the high pressure detection means (9) and simultaneously calculates an estimated value from the detection results of both temperature detection means (8, 10), and the detected value is predetermined for the estimated value. If there is a difference greater than the value, it is stored and held in the correction value map of the detection value correction unit (12a) as a correction value to eliminate the difference .
[0009]
As a result, even if a low-cost, relatively low-precision pressure sensor or a pressure sensor with large manufacturing variations is used, theoretical estimation based on each pressure detection value and suction / discharge temperature of each pressure sensor By storing the deviation from the value as a correction value for each pressure detection value, the refrigerant pressure on the high-pressure side can be detected stably and accurately without causing performance variations among refrigeration cycle apparatuses.
[0010]
The invention according to claim 2 is characterized in that the operation according to claim 1 is performed while the total operating time of the refrigeration cycle apparatus is not more than a predetermined time. The invention according to claim 3 is characterized in that the estimated value is used for controlling the high-pressure side refrigerant pressure while the total operating time of the refrigeration cycle apparatus is not more than a predetermined time.
[0011]
Thus, by accumulating data for a predetermined period and moving to execution, the operation of the refrigeration cycle apparatus can be stabilized and the refrigeration cycle apparatus can be protected. In addition, the code | symbol in the parenthesis attached | subjected to each said means shows the correspondence with the specific means of embodiment description mentioned later.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating a configuration of a refrigeration cycle apparatus according to an embodiment of the present invention. In the present embodiment, the refrigeration cycle apparatus is applied to a heat pump type water heater. The heat pump type water heater in the present embodiment heats hot water supply water to a high temperature (about 90 ° C. in the present embodiment) using a supercritical heat pump cycle, and stores the heated high temperature water in the hot water storage tank 7. The hot water stored in the hot water is mixed with the cold water supplied to supply hot water at a desired temperature.
[0013]
The supercritical heat pump cycle (hereinafter abbreviated as heat pump) refers to a heat pump cycle in which the refrigerant pressure on the high pressure side is equal to or higher than the critical pressure of the refrigerant. In this embodiment, the heat pump cycle uses carbon dioxide (CO ₂ ) as the refrigerant. It is. The heat pump type hot water heater is roughly divided into a refrigeration cycle unit as a heat pump system that mainly stores refrigeration cycle equipment described later, and a tank unit that mainly stores a hot water storage tank 7.
[0014]
The refrigeration cycle unit is roughly composed of a refrigerant circuit (refrigeration cycle) R for a heat pump cycle and a hot water supply heating circuit K for hot water supply. First, the refrigerant circuit R of the heat pump cycle includes a compressor 1 that compresses refrigerant, a water-refrigerant heat exchanger (high-pressure side heat exchanger) 2 that is a heating means for hot water, and a pressure-reducing valve 3 that is a pressure-reducing means. Refrigerant air heat exchanger (low-pressure side heat exchanger) exchanger 4 for absorbing heat from the atmosphere, and an accumulator 5 that stores surplus refrigerant in the heat pump cycle and gas-liquid separates the refrigerant to supply only the gas refrigerant to the compressor 1. And carbon dioxide (CO ₂ ) having a low critical temperature is enclosed as a refrigerant.
[0015]
The compressor 1 includes a built-in drive motor and a high-pressure compressor that discharges the sucked gas refrigerant to a high pressure equal to or higher than the critical pressure, and these are housed in a sealed container. The water-refrigerant heat exchanger 2 heats hot-water supply water by exchanging heat between the high-temperature and high-pressure gas refrigerant boosted by the high-pressure compressor and the hot-water supply water. The hot-water supply water passage 2b is adjacent to the high-pressure refrigerant passage 2a. The flow direction of the refrigerant flowing through the high-pressure refrigerant passage 2a is opposed to the flow direction of hot water flowing through the hot water supply passage 2b.
[0016]
The pressure reducing valve 3 is provided between the water refrigerant heat exchanger 2 and the outdoor heat exchanger 4 and depressurizes the refrigerant cooled by the water refrigerant heat exchanger 2 from a high pressure to a low pressure and supplies the refrigerant to the outdoor heat exchanger 4. To do. Further, the pressure reducing valve 3 has a configuration capable of electrically adjusting the valve opening degree, and is energized and controlled by a control device (control means) 12 described later. The outdoor heat exchanger 4 receives the air blown by the blower fan (cooled medium supply means) 4a, evaporates the refrigerant depressurized by the pressure reducing valve 3 by heat exchange with the atmosphere, and the refrigerant turned into gas is compressed earlier. It is sucked into the machine 1.
[0017]
Next, the hot water supply heating circuit K related to hot water supply includes a hot water supply passage 3b of the water refrigerant heat exchanger 2 which is a heating means for hot water supply, a circulation pump (heated medium supply means) 6 for circulating the hot water supply water, and the like. A hot water storage tank 7 for storing hot water supply water is connected in a ring shape. Circulation pump 6 can adjust the amount of flowing water according to the rotation speed of a built-in motor (not shown). The hot water storage tank 7 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.
[0018]
And the control apparatus 12 sends a signal to the compressor 1, the expansion valve 3, the ventilation fan 4a, and the circulation pump 6, and starts the boiling of hot water. The CO ₂ refrigerant compressed at a high temperature and high pressure by the compressor 1 and the water pumped from the circulation pump 6 by the water refrigerant heat exchanger 2 exchange heat to produce hot water. Thereafter, the CO ₂ refrigerant expands in the expansion valve 3 to become low temperature and low pressure, evaporates in the outdoor heat exchanger 4 and absorbs heat from the atmosphere, and is separated into gas and liquid by the accumulator 5 and returns to the compressor 1.
[0019]
The hot water produced by the water / refrigerant heat exchanger 2 is stored in the hot water storage tank 7. And the hot water for hot water stored in the hot water storage tank 7 is mixed with cold water from the tap water at a temperature adjusting mixing valve (not shown) and adjusted to a predetermined temperature at the time of hot water, and then used mainly by supplying hot water to the kitchen or bath. The
[0020]
Next, the structure regarding the principal part of this invention is demonstrated. The discharge side piping of the compressor 1 is provided with a discharge temperature sensor (discharge temperature detection means) 8 that detects the high-pressure side refrigerant temperature discharged from the compressor 1, and the refrigerant outlet of the water refrigerant heat exchanger 2 has a high pressure. A pressure sensor (high pressure detection means) 9 for detecting a side refrigerant pressure is provided, and a refrigerant outlet side pipe of the outdoor heat exchanger 4 is provided with a suction temperature sensor (suction) for detecting a low pressure side refrigerant temperature sucked by the compressor 1. Temperature detecting means) 10 is provided.
[0021]
Then, the detection values of these sensors 8 to 10 are input to the control device 12, and the control device 12 determines the rotation speed of the compressor 1, the opening degree of the pressure reducing valve 3, the rotation speed of the blower fan 4a based on each detection value, The flow rate of the circulation pump 6 is controlled. Further, the control device 12 includes a detection value correction unit 12a for correcting the detection value of the pressure sensor 9 using the correction value of the correction value map stored and held therein, and the compressor based on the detection results of both the temperature sensors 8 and 10. 1 is provided with an estimated value calculation unit 12b for calculating an estimated value of the high-pressure side refrigerant pressure discharged from the engine 1.
[0022]
Due to the accuracy and variation of the pressure sensor 9, the detected value may deviate from the true pressure value. Therefore, an estimated value from the refrigerant temperature is calculated during the boiling operation, and the detected value is compared with this estimated value. If there is a difference greater than a predetermined value, the detected value stored in the control device 12 is stored. By overwriting the difference in the correction value map as a correction value so that the difference disappears and using it as a correction value later, the detection value can be used with high accuracy.
[0023]
For example, when there is no accumulation in the correction value map at the time of a trial operation of the system, there is a case where accurate high pressure detection cannot be performed due to the accuracy of the pressure sensor 9. Therefore, regarding the boiling operation started within a predetermined time (for example, one week's operation time) after starting to operate the refrigeration cycle apparatus, both the temperature sensors 8 and 10 are used without using the detection value of the pressure sensor 9. Is used. During this predetermined time, correction value data is accumulated in the correction value map.
[0024]
FIG. 2 is a flowchart showing a procedure for storing correction value data in the correction value map. First, in step S1, it is determined whether or not a boiling operation is being performed. If the determination result is NO and the state is other than the boiling operation, the process returns to repeat the determination in step S1. On the other hand, if the determination result is YES and the vehicle is in a boiling operation state, the process proceeds to step S2.
[0025]
Next, it is determined in step S2 whether or not the total operating time of the refrigeration cycle apparatus is equal to or shorter than a predetermined time. If the determination result is NO and the predetermined time is exceeded, the following processing is not performed. On the other hand, if the determination result is YES and the time is equal to or shorter than the predetermined time, the process proceeds to step S3 and the following processing is performed.
[0026]
In step S3, the high pressure side refrigerant pressure is detected by the pressure sensor 9, and the detected value is taken in. In step S4, the high-pressure side refrigerant temperature and the low-pressure side refrigerant temperature are detected by both temperature sensors 8 and 10, and the detected values are taken in, and the estimated value calculation unit 12b detects the detection results of both temperature sensors 8 and 10. From the above, an estimated value of the high-pressure side refrigerant pressure discharged from the compressor 1 is calculated. In step S5, the difference between the calculated estimated value and the value detected by the pressure sensor 9 is calculated.
[0027]
In the next step S6, it is determined whether or not the difference calculated in step S5 is greater than or equal to a predetermined value. If the determination result is NO and the difference is less than or equal to a predetermined value, the process returns and no processing is performed, but if the determination result is YES and the difference is greater than or equal to the predetermined value, the process proceeds to step S7. The calculated difference is stored and held in the correction value map of the detection value correction unit 12a as a correction value for the detection value at that time.
[0028]
Next, features of this embodiment will be described. First, the control device 12 is provided with a detection value correction unit 12a that corrects the detection value of the pressure sensor 9 using the correction value of the correction value map stored and held therein. As a result, even when using a low-cost, relatively low-precision pressure sensor or a pressure sensor with large manufacturing variations, the refrigerant pressure on the high-pressure side can be stably and accurately maintained without causing performance variations among refrigeration cycle apparatuses. Can be detected.
[0029]
The refrigeration cycle apparatus includes a suction temperature sensor 10 that detects a low-pressure side refrigerant temperature sucked by the compressor 1, a discharge temperature sensor 8 that detects a high-pressure side refrigerant temperature discharged by the compressor 1, and a control device 12. An estimated value calculation unit 12b for calculating an estimated value of the high-pressure side refrigerant pressure discharged from the compressor 1 from the detection results of the temperature sensors 8 and 10 is provided, and the control device 12 takes in the detected value of the pressure sensor 9 at the same time. When the estimated value is calculated from the detection results of both the temperature sensors 8 and 10, and the detected value has a difference of a predetermined value or more with respect to the estimated value, the correction value of the detected value correction unit 12a is used as a correction value to eliminate the difference. Stored in the map.
[0030]
As a result, even if a low-cost, relatively low-precision pressure sensor or a pressure sensor with large manufacturing variations is used, theoretical estimation based on each pressure detection value and suction / discharge temperature of each pressure sensor By storing the deviation from the value as a correction value for each pressure detection value, the refrigerant pressure on the high-pressure side can be detected stably and accurately without causing performance variations among refrigeration cycle apparatuses.
[0031]
Further, the above operation is performed while the total operation time of the refrigeration cycle apparatus is a predetermined time or less, and the estimated value is used for controlling the high-pressure side refrigerant pressure without using the detected value. Thus, by accumulating data for a predetermined period and moving to execution, the operation of the refrigeration cycle apparatus can be stabilized and the refrigeration cycle apparatus can be protected.
[0032]
(Other embodiments)
In the above-described embodiment, the suction temperature sensor 10 provided in the refrigerant outlet side pipe of the outdoor heat exchanger 4 is used as the suction temperature detection means for detecting the low-pressure side refrigerant temperature sucked by the compressor 1. 11 (see FIG. 1) may be used as a substitute for the temperature of the air that has passed through the outdoor heat exchanger 4.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a configuration of a refrigeration cycle apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a procedure for accumulating correction value data in a correction value map.
[Explanation of symbols]
1 Compressor 2 Water refrigerant heat exchanger (high pressure side heat exchanger)
3 Expansion valve (pressure reduction means)
4 Outdoor heat exchanger (low pressure side heat exchanger)
4a Blower fan (cooled medium supply means)
6 Circulation pump (heated medium supply means)
8 Discharge temperature sensor (Discharge temperature detection means)
9 Pressure sensor (High pressure detection means)
10 Suction temperature sensor (suction temperature detection means)
12 Control device (control means)
12a Detection value correction unit 12b Estimated value calculation unit R Refrigeration cycle

Claims

A refrigeration cycle (R) formed by connecting at least a compressor (1), a high-pressure side heat exchanger (2), a decompression means (3), and a low-pressure side heat exchanger (4) by liquid piping and gas piping;
Heated medium supply means (6) for supplying a heated medium to the high pressure side heat exchanger (2), and a cooled medium supply for supplying a cooled medium to the low pressure side heat exchanger (4) Means (4a);
High pressure detecting means (9) for detecting the high pressure side refrigerant pressure discharged from the compressor (1);
Based on the detection result of the high pressure detection means (9), among the opening degree of the decompression means (3), the rotational speed of the compressor (1), the flow rate of the heated medium, and the flow rate of the cooled medium Control means (12) for controlling at least one to control a high pressure side refrigerant pressure range in which the coefficient of performance of the refrigeration cycle (R) is near the maximum ;
A detection value correction unit (12a) for correcting the detection value of the high pressure detection means (9) using the correction value of the correction value map stored and held in the control means (12) ;
A suction temperature detecting means (10) for detecting the temperature of the low-pressure side refrigerant sucked by the compressor (1) and a discharge temperature detecting means (8) for detecting the temperature of the high-pressure side refrigerant discharged by the compressor (1). When,
An estimated value calculating section (12b) for calculating an estimated value of the high-pressure side refrigerant pressure discharged from the compressor (1) from the detection results of the temperature detecting means (8, 10) in the control means (12); With
The control means (12) takes in the detection value of the high pressure detection means (9) and simultaneously calculates an estimation value from the detection results of the temperature detection means (8, 10). A refrigeration cycle apparatus characterized in that when a detected value has a difference of a predetermined value or more, a correction value map of the detected value correction unit (12a) is stored and held as a correction value to eliminate the difference .

Wherein during the total operating time of the refrigerating cycle apparatus is less than a predetermined time, refrigeration cycle apparatus and performs operation according to claim 1.

During the total operating time of the refrigerating cycle apparatus is less than a predetermined time, refrigeration cycle apparatus according to claim 1, characterized by using the estimated value without using the detection value to the control of the high-pressure side refrigerant pressure.