JP2021152448A

JP2021152448A - Heat pump device

Info

Publication number: JP2021152448A
Application number: JP2021108262A
Authority: JP
Inventors: 快佐藤; Kai Sato; 隆志眞柄; Takashi Magara; 真典上田; Masanori Ueda; 岳彦川上; Takehiko Kawakami; 正巳山口; Masami Yamaguchi
Original assignee: Corona Corp
Current assignee: Corona Corp
Priority date: 2017-12-27
Filing date: 2021-06-30
Publication date: 2021-09-30
Anticipated expiration: 2037-12-27
Also published as: JP6907110B2; JP7074915B2; JP2019117035A

Abstract

To provide a heat pump device in which the circulating liquid in the liquid refrigerant heat exchanger does not freeze during defrosting operation.SOLUTION: There is provided a heat pump device that performs heating operation to heat the circulating fluid, comprising a liquid refrigerant heat exchanger 4 that exchanges heat between the circulating liquid and the refrigerant, an air heat exchanger 7 that exchanges heat between the outside air and the refrigerant, a heat pump circuit 9 that circulates the refrigerant, a circulation pump 15 that circulates the circulating liquid in the liquid refrigerant heat exchanger 4 and the liquid refrigerant heat exchanger 4, and a circulation circuit 13 in which the circulating fluid circulates. A control device 18 controls flow path switching means 3 so that the flow direction of the refrigerant is the same as that during the heating operation when the defrosting operation is executed during the heating operation, and switches the flow path switching means 3 so that the flow direction of the refrigerant is opposite to that during the heating operation and executes the reverse cycle defrosting operation after it executes the positive cycle defrosting operation in which the opening degree of an expansion valve 5 is enlarged compared to the heating operation and the refrigerant is circulated until the refrigerant temperature in the air heat exchanger 7 rises to the temperature at which the circulating liquid does not freeze.SELECTED DRAWING: Figure 4

Description

本発明は、空気熱交換器の霜を溶かす除霜運転を行うヒートポンプ装置に関するものである。 The present invention relates to a heat pump device that performs a defrosting operation for melting frost in an air heat exchanger.

従来この種のものでは、圧縮機、四方弁、液冷媒熱交換器、膨張弁、空気熱交換器を冷媒配管で接続したヒートポンプ回路を備え、液冷媒熱交換器において、冷媒と循環液とを熱交換させ、熱交換によって加熱された循環液を床暖房パネル等の熱交換端末に供給し、被空調空間を加熱する暖房運転を行うものがあり、暖房運転を行っているときに、外気温度や暖房負荷の大きさ等、条件によっては空気熱交換器が着霜することがあり、空気熱交換器は着霜すると熱交換効率が低下するため、空気熱交換器の除霜をする必要がある。この場合、四方弁を、冷媒の流れ方向が暖房運転時の冷媒の流れ方向と逆になるように切り換えて、圧縮機から吐出された冷媒を空気熱交換器に直接供給して空気熱交換器に発生した霜を溶かす、いわゆる逆サイクル除霜運転を行うものがあった。（例えば、特許文献１参照。） Conventionally, this type has a heat pump circuit in which a compressor, a four-way valve, a liquid refrigerant heat exchanger, an expansion valve, and an air heat exchanger are connected by a refrigerant pipe, and in the liquid refrigerant heat exchanger, the refrigerant and the circulating liquid are exchanged. Some perform a heating operation in which heat is exchanged and the circulating liquid heated by the heat exchange is supplied to a heat exchange terminal such as a floor heating panel to heat the space to be air-conditioned. Depending on the conditions such as the size of the heating load and the size of the heating load, the air heat exchanger may frost, and if the air heat exchanger frosts, the heat exchange efficiency will decrease, so it is necessary to defrost the air heat exchanger. be. In this case, the four-way valve is switched so that the flow direction of the refrigerant is opposite to the flow direction of the refrigerant during the heating operation, and the refrigerant discharged from the compressor is directly supplied to the air heat exchanger to be the air heat exchanger. There was a so-called reverse cycle defrosting operation that melts the frost generated in the air. (See, for example, Patent Document 1.)

特開２０１６−１５６６０２号公報Japanese Unexamined Patent Publication No. 2016-156602

ところで、この従来のものは、逆サイクル除霜運転が開始されると、それまで空気熱交換器内にあった冷媒は膨張弁側を回って液冷媒熱交換器に流れ込むことになるものであるが、空気熱交換器は逆サイクル除霜運転開始前の暖房運転時は蒸発器として機能しており、この時の空気熱交換器での冷媒温度は外気温度よりも低く、空気熱交換器が着霜しているときには空気熱交換器内の冷媒温度はマイナス域となる。 By the way, in this conventional one, when the reverse cycle defrosting operation is started, the refrigerant that had been in the air heat exchanger until then goes around the expansion valve side and flows into the liquid refrigerant heat exchanger. However, the air heat exchanger functions as an evaporator during the heating operation before the start of the reverse cycle defrosting operation, and the refrigerant temperature in the air heat exchanger at this time is lower than the outside air temperature, and the air heat exchanger is When frost is formed, the temperature of the refrigerant in the air heat exchanger is in the negative range.

上記のような状態で逆サイクル除霜運転は開始されるものであるが、逆サイクル除霜運転が開始されると、空気熱交換器内に保有されたマイナス域の温度の冷媒が、液冷媒熱交換器に流れ込むことになり、液冷媒熱交換器は急速に冷却され、液冷媒熱交換器内でマイナス域の温度の冷媒と熱交換された循環液が凍結する可能性があり、循環液の凍結により液冷媒熱交換器が破損するおそれがあった。 The reverse cycle defrosting operation is started in the above state, but when the reverse cycle defrosting operation is started, the negative temperature refrigerant held in the air heat exchanger becomes a liquid refrigerant. As it flows into the heat exchanger, the liquid refrigerant heat exchanger is cooled rapidly, and the circulating fluid that has been heat-exchanged with the refrigerant in the negative range temperature in the liquid refrigerant heat exchanger may freeze, and the circulating fluid may freeze. There was a risk of damage to the liquid refrigerant heat exchanger due to freezing.

本発明は上記課題を解決するために、請求項１では、冷媒を圧縮する圧縮機と、流路切換手段と、循環液と前記冷媒とを熱交換させる液冷媒熱交換器と、膨張弁と、外気と前記冷媒とを熱交換させる空気熱交換器とを有し、前記冷媒が循環するヒートポンプ回路と、前記液冷媒熱交換器と、前記液冷媒熱交換器に前記循環液を循環させる循環ポンプとを有し、前記循環液が循環する循環回路と、動作を制御する制御装置とを備え、前記ヒートポンプ回路を作動させると共に前記循環ポンプを駆動させて、前記循環液を加熱する暖房運転を行うヒートポンプ装置において、前記制御装置は、前記暖房運転中に、前記空気熱交換器に発生した霜を溶かす除霜運転を実行する場合、前記冷媒の流れ方向が前記暖房運転時の前記冷媒の流れ方向と同じになるように前記流路切換手段を制御すると共に、前記膨張弁の開度を前記暖房運転時よりも拡大させて、前記冷媒を循環させる正サイクル除霜運転を、前記空気熱交換器内の前記冷媒の温度が前記循環液が凍結しない温度に上昇するまで実行した後、前記冷媒の流れ方向が前記暖房運転時の前記冷媒の流れ方向と逆になるように前記流路切換手段を切り換えて、前記冷媒を循環させる逆サイクル除霜運転を実行するようにし、前記逆サイクル除霜運転の実行中に予め定められている除霜終了条件が成立したら前記逆サイクル除霜運転を終了させて前記暖房運転を再開させるようにした。 In order to solve the above problems, in claim 1, the present invention includes a compressor for compressing the refrigerant, a flow path switching means, a liquid refrigerant heat exchanger for heat exchange between the circulating liquid and the refrigerant, and an expansion valve. A heat pump circuit that has an air heat exchanger that exchanges heat between the outside air and the refrigerant, and circulates the circulating liquid in the liquid refrigerant heat exchanger and the liquid refrigerant heat exchanger. It has a pump, includes a circulation circuit in which the circulating fluid circulates, and a control device for controlling the operation, and operates the heat pump circuit and drives the circulation pump to heat the circulating fluid. In the heat pump device to be performed, when the control device executes a defrosting operation for melting the frost generated in the air heat exchanger during the heating operation, the flow direction of the refrigerant is the flow of the refrigerant during the heating operation. The air heat exchange is performed in a positive cycle defrosting operation in which the flow path switching means is controlled so as to be in the same direction, the opening degree of the expansion valve is expanded compared to the heating operation, and the refrigerant is circulated. After executing until the temperature of the refrigerant in the vessel rises to a temperature at which the circulating fluid does not freeze, the flow path switching means so that the flow direction of the refrigerant is opposite to the flow direction of the refrigerant during the heating operation. Is switched to execute the reverse cycle defrosting operation in which the refrigerant is circulated, and the reverse cycle defrosting operation is terminated when a predetermined defrosting end condition is satisfied during the execution of the reverse cycle defrosting operation. The heating operation was restarted.

また、請求項２では、前記膨張弁から前記空気熱交換器までの冷媒配管に冷媒温度センサを設け、前記制御装置は、前記冷媒温度センサで検出される冷媒温度が前記循環液が凍結しない温度に上昇するまで前記正サイクル除霜運転を実行するようにした。 Further, in claim 2, a refrigerant temperature sensor is provided in the refrigerant pipe from the expansion valve to the air heat exchanger, and the control device has a temperature at which the refrigerant temperature detected by the refrigerant temperature sensor does not freeze the circulating fluid. The positive cycle defrosting operation is executed until the temperature rises to.

この発明によれば、制御装置は、暖房運転中に、除霜運転を実行する場合、冷媒の流れ方向が暖房運転時の冷媒の流れ方向と同じになるように流路切換手段を制御すると共に、膨張弁の開度を暖房運転時よりも拡大させて、冷媒を循環させる正サイクル除霜運転を実行した後、冷媒の流れ方向が暖房運転時の冷媒の流れ方向と逆になるように流路切換手段を切り換えて、冷媒を循環させる逆サイクル除霜運転を実行するようにしたことで、正サイクル除霜運転により、ヒートポンプ回路を循環する冷媒のうち、冷媒温度が一番低い空気熱交換器内の冷媒の最低温度値を、循環液が凍結しない温度に上昇させ、それから逆サイクル除霜運転を行うので、逆サイクル除霜運転時に、空気熱交換器から流出して膨張弁側から回ってきた冷媒が液冷媒熱交換器に流入しても、液冷媒熱交換器内の循環液が凍結することはなく、循環液の凍結による液冷媒熱交換器の破損もないものである。 According to the present invention, when the defrosting operation is executed during the heating operation, the control device controls the flow path switching means so that the flow direction of the refrigerant is the same as the flow direction of the refrigerant during the heating operation. After performing a positive cycle defrosting operation in which the refrigerant is circulated by expanding the opening of the expansion valve compared to that during the heating operation, the flow direction of the refrigerant is opposite to that during the heating operation. By switching the path switching means to execute the reverse cycle defrosting operation that circulates the refrigerant, the air heat exchange with the lowest refrigerant temperature among the refrigerants that circulate in the heat pump circuit by the normal cycle defrosting operation. Since the minimum temperature value of the refrigerant in the vessel is raised to a temperature at which the circulating fluid does not freeze, and then the reverse cycle defrosting operation is performed, it flows out of the air heat exchanger and rotates from the expansion valve side during the reverse cycle defrosting operation. Even if the incoming refrigerant flows into the liquid refrigerant heat exchanger, the circulating liquid in the liquid refrigerant heat exchanger does not freeze, and the liquid refrigerant heat exchanger is not damaged due to freezing of the circulating liquid.

本発明の一実施形態のヒートポンプ装置の概略構成図。The schematic block diagram of the heat pump apparatus of one Embodiment of this invention. ヒートポンプ装置の暖房運転時および正サイクル除霜運転時の動作を説明する概略構成図。The schematic block diagram explaining the operation in the heating operation and the normal cycle defrosting operation of a heat pump device. ヒートポンプ装置の逆サイクル除霜運転時の動作を説明する概略構成図。The schematic block diagram explaining the operation at the time of the reverse cycle defrosting operation of a heat pump apparatus. ヒートポンプ装置の暖房運転時に除霜運転が実行される場合の動作を示すタイムチャート。A time chart showing the operation when the defrosting operation is executed during the heating operation of the heat pump device. 外気温度と所定時間との対応関係を表す図。The figure which shows the correspondence relationship between the outside air temperature and a predetermined time.

次に、この発明の一実施形態のヒートポンプ装置の構成について、図面に基づき詳細に説明する。なお、このヒートポンプ装置は、暖房装置および冷房装置として機能させることができるが、以下の実施形態においては主として暖房装置として使用している場合の構成要素および動作について説明する。 Next, the configuration of the heat pump device according to the embodiment of the present invention will be described in detail with reference to the drawings. Although this heat pump device can function as a heating device and a cooling device, the components and operations when the heat pump device is mainly used as a heating device will be described in the following embodiments.

１は加熱された循環液を供給するヒートポンプ式の熱源機としてのヒートポンプユニットで、ヒートポンプユニット１は、その筐体内に、冷媒を圧縮する回転数可変の圧縮機２、流路切換手段としての四方弁３、冷媒と循環液との熱交換を行う液冷媒熱交換器４、減圧手段としての膨張弁５、送風ファン６の作動により送られる空気（外気）との熱交換を行う空気熱交換器７とを有し、それらを冷媒配管８で環状に接続して冷媒が循環するヒートポンプ回路９を形成しているものである。前記液冷媒熱交換器４は、例えば、プレート式熱交換器で構成され、プレート式熱交換器は、複数の伝熱プレートが積層され、冷媒を流通させる冷媒流路と循環液を流通させる液流路とが各伝熱プレートを境にして交互に形成されている。なお、ヒートポンプ回路９を循環する冷媒としては、ＨＦＣ冷媒や二酸化炭素冷媒等の任意の冷媒を用いることができるものである。 Reference numeral 1 denotes a heat pump unit as a heat pump type heat source machine for supplying a heated circulating fluid. A valve 3, a liquid refrigerant heat exchanger that exchanges heat between the refrigerant and the circulating fluid, an expansion valve 5 as a depressurizing means, and an air heat exchanger that exchanges heat with the air (outside air) sent by the operation of the blower fan 6. 7 and 7 are connected in a ring shape by a refrigerant pipe 8 to form a heat pump circuit 9 in which a refrigerant circulates. The liquid refrigerant heat exchanger 4 is composed of, for example, a plate type heat exchanger. In the plate type heat exchanger, a plurality of heat transfer plates are laminated, and a refrigerant flow path through which the refrigerant flows and a liquid through which the circulating liquid flows. The flow paths are formed alternately with each heat transfer plate as a boundary. As the refrigerant that circulates in the heat pump circuit 9, any refrigerant such as an HFC refrigerant or a carbon dioxide refrigerant can be used.

１０は外気温度を検出する外気温度センサ、１１は膨張弁５から空気熱交換器７までの冷媒配管８に設けられ、冷媒温度を検出する冷媒温度センサである。 Reference numeral 10 denotes an outside air temperature sensor that detects the outside air temperature, and reference numeral 11 denotes a refrigerant temperature sensor that is provided in the refrigerant pipe 8 from the expansion valve 5 to the air heat exchanger 7 and detects the refrigerant temperature.

前記冷媒配管８に設けられた四方弁３は、ヒートポンプ回路９における冷媒の流れ方向を切り換える機能を有し、圧縮機２から吐出された冷媒を、液冷媒熱交換器４、膨張弁５、空気熱交換器７の順に流通させ、圧縮機２に戻す流路を形成する状態（暖房運転時および正サイクル除霜運転時の状態）と、圧縮機２から吐出された冷媒を、空気熱交換器７、膨張弁５、液冷媒熱交換器４の順に流通させ、圧縮機２に戻す流路を形成する状態（逆サイクル除霜運転時の状態）とに切換可能なものである。 The four-way valve 3 provided in the refrigerant pipe 8 has a function of switching the flow direction of the refrigerant in the heat pump circuit 9, and uses the refrigerant discharged from the compressor 2 as the liquid refrigerant heat exchanger 4, the expansion valve 5, and air. The air heat exchanger exchanges the state in which the heat exchanger 7 is circulated in this order to form a flow path for returning to the compressor 2 (the state during the heating operation and the state during the normal cycle defrosting operation) and the refrigerant discharged from the compressor 2. It is possible to switch to a state in which the expansion valve 5 and the liquid refrigerant heat exchanger 4 are circulated in this order to form a flow path for returning to the compressor 2 (state during reverse cycle defrosting operation).

１２はヒートポンプユニット１で加熱された循環液が供給され、供給された循環液の熱を利用することで被空調空間の空調を行う熱交換端末であり、熱交換端末１２としては暖房専用端末である床暖房パネルやラジエータ、冷暖房兼用端末である輻射パネルやファンコイル等を用いるものである。図１では１つしか設けられていないが、複数であってもよいものであり、数量や仕様が特に限定されるものではない。 Reference numeral 12 denotes a heat exchange terminal to which the circulating liquid heated by the heat pump unit 1 is supplied and air-conditioning the air-conditioned space by utilizing the heat of the supplied circulating liquid. The heat exchange terminal 12 is a dedicated heating terminal. A certain floor heating panel, radiator, radiation panel, fan coil, etc., which are terminals for both heating and cooling, are used. Although only one is provided in FIG. 1, a plurality of them may be provided, and the quantity and specifications are not particularly limited.

１３は液冷媒熱交換器４と熱交換端末１２とを液配管１４で環状に接続し、循環液（例えば、水や不凍液等）が循環する循環回路で、循環回路１３は、循環回路１３に循環液を循環させる回転数可変の循環ポンプ１５と、熱交換端末１２から液冷媒熱交換器４に流入する循環液の温度を検出する戻り温度センサ１６と、循環液を貯留し循環回路１３内の圧力を調整するシスターン１７とを備えているものである。 Reference numeral 13 denotes a circulation circuit in which the liquid refrigerant heat exchanger 4 and the heat exchange terminal 12 are connected in a ring shape by a liquid pipe 14 to circulate the circulating liquid (for example, water, antifreeze liquid, etc.). A circulation pump 15 having a variable rotation speed for circulating the circulating fluid, a return temperature sensor 16 for detecting the temperature of the circulating fluid flowing into the liquid refrigerant heat exchanger 4 from the heat exchange terminal 12, and a circulation circuit 13 for storing the circulating fluid. It is equipped with a systurn 17 that adjusts the pressure of the.

１８は各種のデータやプログラムを記憶する記憶手段と、演算・制御処理を行う制御手段とを備え、ヒートポンプ装置の動作を制御する制御装置であり、制御装置１８はヒートポンプユニット１内の各種センサの信号やリモコン１９からの信号を受け、圧縮機２、四方弁３、膨張弁５、送風ファン６、循環ポンプ１５の駆動を制御するものである。 Reference numeral 18 denotes a control device including a storage means for storing various data and programs and a control means for performing calculation / control processing, and controlling the operation of the heat pump device. The control device 18 is a control device for various sensors in the heat pump unit 1. It receives a signal or a signal from the remote control 19 and controls the drive of the compressor 2, the four-way valve 3, the expansion valve 5, the blower fan 6, and the circulation pump 15.

前記制御装置１８は、ヒートポンプ回路９を作動させると共に循環ポンプ１５を駆動させて、液冷媒熱交換器４において循環液を加熱し、加熱された循環液を熱交換端末１２に供給し、被空調空間を加熱する暖房運転中に、所定の除霜開始条件が成立したと判断すると空気熱交換器の霜を溶かす除霜運転を実行させるものである。 The control device 18 operates the heat pump circuit 9 and drives the circulation pump 15, heats the circulating liquid in the liquid refrigerant heat exchanger 4, supplies the heated circulating liquid to the heat exchange terminal 12, and is air-conditioned. During the heating operation for heating the space, if it is determined that the predetermined defrosting start condition is satisfied, the defrosting operation for melting the frost of the air heat exchanger is executed.

前記制御装置１８は、前記暖房運転中に所定の除霜開始条件が成立したと判断すると、前記除霜運転として、冷媒の流れ方向を暖房運転時から変更することなく暖房運転時の冷媒の流れ方向と同方向とし、冷媒を循環させて空気熱交換器７に発生した霜を溶かす正サイクル除霜運転を実行させた後に、冷媒の流れ方向が暖房運転時の冷媒の流れ方向と逆になるように四方弁３を切り換えて、圧縮機２から吐出された高温冷媒を直接、空気熱交換器７に循環させて、空気熱交換器７に発生した霜を溶かす逆サイクル除霜運転を実行させるものである。なお、前記除霜運転の詳細な動作については後述する。 When the control device 18 determines that the predetermined defrosting start condition is satisfied during the heating operation, the refrigerant flow during the heating operation is performed as the defrosting operation without changing the flow direction of the refrigerant from the heating operation. After executing a normal cycle defrosting operation in which the direction is the same as the direction and the refrigerant is circulated to melt the frost generated in the air heat exchanger 7, the flow direction of the refrigerant becomes opposite to the flow direction of the refrigerant during the heating operation. By switching the four-way valve 3 as described above, the high-temperature refrigerant discharged from the compressor 2 is directly circulated to the air heat exchanger 7 to execute a reverse cycle defrosting operation for melting the frost generated in the air heat exchanger 7. It is a thing. The detailed operation of the defrosting operation will be described later.

また、前記除霜運転の開始は、例えば、外気温度センサ１０で検出した外気温度が予め設定された除霜開始温度に達したか否か、または外気温度センサ１０で検出した外気温度および冷媒温度センサ１１で検出した冷媒温度がそれぞれ予め設定された除霜開始温度に達したか否かを制御装置１８が判断、すなわち所定の除霜開始条件が成立したか否かを制御装置１８が判断して、除霜開始条件が成立したと判断したら前記除霜運転を開始することができる。また、前記除霜運転の完了は、冷媒温度センサ１１で検出する空気熱交換器７を流通してきた冷媒の温度が、予め設定された除霜終了温度に達したか否かを制御装置１８が判断、すなわち所定の除霜終了条件が成立したか否かを制御装置１８が判断して、除霜終了条件が成立したと判断したら除霜動作を終了することができる。 Further, the start of the defrosting operation is, for example, whether or not the outside air temperature detected by the outside air temperature sensor 10 has reached a preset defrosting start temperature, or the outside air temperature and the refrigerant temperature detected by the outside air temperature sensor 10. The control device 18 determines whether or not the refrigerant temperature detected by the sensor 11 has reached a preset defrost start temperature, that is, the control device 18 determines whether or not a predetermined defrost start condition is satisfied. Then, when it is determined that the defrosting start condition is satisfied, the defrosting operation can be started. Further, when the defrosting operation is completed, the control device 18 determines whether or not the temperature of the refrigerant flowing through the air heat exchanger 7 detected by the refrigerant temperature sensor 11 has reached a preset defrosting end temperature. The control device 18 determines whether or not the predetermined defrosting end condition is satisfied, and if it is determined that the defrosting end condition is satisfied, the defrosting operation can be terminated.

次に、ヒートポンプ装置の暖房運転時の動作について図２を用いて説明する。図２中の矢線は、ヒートポンプ回路９を流れる冷媒の流れ方向、循環回路１３を流れる循環液の流れ方向をそれぞれ示したものである。なお、本実施形態のヒートポンプ装置では冷房運転を行うこともできるが、ここでは暖房運転時の動作のみを説明するものとし、冷房運転の説明は省略する。 Next, the operation of the heat pump device during the heating operation will be described with reference to FIG. The arrow lines in FIG. 2 indicate the flow direction of the refrigerant flowing through the heat pump circuit 9, and the flow direction of the circulating liquid flowing through the circulation circuit 13, respectively. Although the heat pump device of the present embodiment can perform the cooling operation, only the operation during the heating operation will be described here, and the description of the cooling operation will be omitted.

リモコン１９から、液冷媒熱交換器４において循環液を加熱し熱交換端末１２に供給する暖房運転の指示がなされると、制御装置１８は、四方弁３を暖房運転時の状態となるように流路を切り換え、圧縮機２、膨張弁５、送風ファン６を駆動させ、ヒートポンプ回路９を作動させると共に、循環ポンプ１５を駆動させて暖房運転を開始させ、冷媒は、圧縮機２、四方弁３、液冷媒熱交換器４、膨張弁５、空気熱交換器７、四方弁３、圧縮機２の順で循環し（図２のヒートポンプ回路９の矢線参照。）、循環液は液冷媒熱交換器４から熱交換端末１２に循環され、熱交換端末１２から再度、液冷媒熱交換器４に戻されるものである（図２の循環回路１３の矢線参照。）。この時、液冷媒熱交換器４は凝縮器として機能し、空気熱交換器７は蒸発器として機能するものである。 When the remote control 19 gives an instruction for a heating operation in which the liquid refrigerant heat exchanger 4 heats the circulating liquid and supplies it to the heat exchange terminal 12, the control device 18 causes the four-way valve 3 to be in the state during the heating operation. The flow path is switched, the compressor 2, the expansion valve 5, and the blower fan 6 are driven to operate the heat pump circuit 9, and the circulation pump 15 is driven to start the heating operation. 3. Liquid refrigerant heat exchanger 4, expansion valve 5, air heat exchanger 7, four-way valve 3, compressor 2 circulate in this order (see the arrow in heat pump circuit 9 in FIG. 2), and the circulating liquid is liquid refrigerant. It is circulated from the heat exchanger 4 to the heat exchange terminal 12 and returned from the heat exchange terminal 12 to the liquid refrigerant heat exchanger 4 again (see the arrow line in the circulation circuit 13 in FIG. 2). At this time, the liquid refrigerant heat exchanger 4 functions as a condenser, and the air heat exchanger 7 functions as an evaporator.

制御装置１８は、暖房運転中、循環液の温度を検出する戻り温度センサ１６の検出値が、リモコン１９の設定温度に基づいて設定される目標温度になるように、圧縮機２の回転数を制御するものである。 The control device 18 sets the number of revolutions of the compressor 2 so that the detection value of the return temperature sensor 16 that detects the temperature of the circulating fluid during the heating operation becomes the target temperature set based on the set temperature of the remote controller 19. It controls.

前記暖房運転中、ヒートポンプ回路９において、液冷媒熱交換器４は凝縮器として機能し、液冷媒熱交換器４にて圧縮機２から吐出された高温高圧の気相状態の冷媒と循環ポンプ１５により循環される循環液とが熱交換され、冷媒の熱によって循環液が加熱される。一方、空気熱交換器７は蒸発器として機能し、空気熱交換器７にて膨張弁５から吐出された低温低圧の気液二相状態の冷媒と送風ファン６を駆動させることで送風される外気とが熱交換され、冷媒は外気から吸熱して気相状態へと変化し、圧縮機２へ戻るものである。 During the heating operation, in the heat pump circuit 9, the liquid refrigerant heat exchanger 4 functions as a condenser, and the high temperature and high pressure vapor phase refrigerant discharged from the compressor 2 in the liquid refrigerant heat exchanger 4 and the circulation pump 15 The circulating liquid is heat-exchanged with the circulating liquid circulated by the refrigerant, and the circulating liquid is heated by the heat of the refrigerant. On the other hand, the air heat exchanger 7 functions as an evaporator, and is blown by driving the low-temperature low-pressure gas-liquid two-phase state refrigerant discharged from the expansion valve 5 and the blower fan 6 by the air heat exchanger 7. The heat is exchanged with the outside air, the refrigerant absorbs heat from the outside air, changes to the vapor phase state, and returns to the compressor 2.

また、前記暖房運転中、循環回路１３では、液冷媒熱交換器４で加熱された循環液は、循環ポンプ１５の駆動により熱交換端末１２に供給され、被空調空間の内気に対して放熱して被空調空間を加温し、熱交換端末１２を流出した循環液は再び液冷媒熱交換器４に戻され加温されるものである。 Further, during the heating operation, in the circulation circuit 13, the circulating liquid heated by the liquid refrigerant heat exchanger 4 is supplied to the heat exchange terminal 12 by the drive of the circulation pump 15 and dissipates heat to the inside air of the air-conditioned space. The air-conditioned space is heated, and the circulating liquid flowing out of the heat exchange terminal 12 is returned to the liquid refrigerant heat exchanger 4 and heated.

この暖房運転中に、制御装置１８が所定の除霜開始条件が成立したと判断すると、除霜運転の実行を開始するものであり、除霜運転として、まず、正サイクル除霜運転を所定時間行う。正サイクル除霜運転の形態は、図２に示すように、暖房運転時と同方向に冷媒を循環させる形態（図２のヒートポンプ回路９の矢線参照。）であり、具体的な正サイクル除霜運転の動作としては、制御装置１８は圧縮機２の回転数を予め設定された除霜時回転数に制御すると共に、膨張弁５を除霜運転前の暖房運転時よりも所定の開度まで拡大、ここでは全開まで拡大させ、循環ポンプ１５の回転数を予め設定された除霜時回転数とする。この時、圧縮機２から吐出された高温の冷媒は、液冷媒熱交換器４で循環液と熱交換し、液冷媒熱交換器４を流出した後に膨張弁５を通過して空気熱交換器７に供給され、空気熱交換器７の除霜が行われるものであり、この正サイクル除霜運転時は、膨張弁５の開度を所定の開度である全開まで拡大することで、膨張弁５では冷媒は減圧されることなく通過して、冷媒は暖かいまま空気熱交換器７に供給され、空気熱交換器７に発生した霜を溶かすものである。 If the control device 18 determines that the predetermined defrosting start condition is satisfied during the heating operation, the execution of the defrosting operation is started. As the defrosting operation, first, the normal cycle defrosting operation is performed for a predetermined time. conduct. As shown in FIG. 2, the mode of the normal cycle defrosting operation is a mode in which the refrigerant is circulated in the same direction as during the heating operation (see the arrow line of the heat pump circuit 9 in FIG. 2), and a specific normal cycle defrosting operation is performed. As an operation of the frost operation, the control device 18 controls the rotation speed of the compressor 2 to a preset rotation speed at the time of defrosting, and the expansion valve 5 has a predetermined opening degree as compared with the heating operation before the defrosting operation. The number of revolutions of the circulation pump 15 is set to a preset number of revolutions at the time of defrosting. At this time, the high-temperature refrigerant discharged from the compressor 2 exchanges heat with the circulating liquid in the liquid refrigerant heat exchanger 4, flows out of the liquid refrigerant heat exchanger 4, passes through the expansion valve 5, and is an air heat exchanger. It is supplied to the air heat exchanger 7 to defrost the air heat exchanger 7. During this positive cycle defrosting operation, the expansion valve 5 expands by expanding the opening degree to a predetermined opening degree. In the valve 5, the refrigerant passes through without being depressurized, the refrigerant is supplied to the air heat exchanger 7 while being warm, and the frost generated in the air heat exchanger 7 is melted.

前記正サイクル除霜運転が所定時間行われると、次に、除霜運転として、逆サイクル除霜運転を開始する。逆サイクル除霜運転の形態は、図３に示すように、冷媒を、圧縮機２、四方弁３、空気熱交換器７、膨張弁５、液冷媒熱交換器４、四方弁３、圧縮機２の順で循環させ、暖房運転時と逆方向に冷媒を循環させる形態（図３のヒートポンプ回路９の矢線参照。）であり、具体的な逆サイクル除霜運転の動作としては、制御装置１８は、四方弁３を冷媒の流れ方向が暖房運転時の冷媒の流れ方向と逆になるように切り換え、圧縮機２の回転数を正サイクル除霜運転と同様の除霜時回転数に制御すると共に、膨張弁５を全開とし、循環ポンプ１５を最大回転数で駆動させる。この時、圧縮機２から吐出された高温の冷媒は、空気熱交換器７に直接供給され、空気熱交換器７に発生した霜を溶かす。空気熱交換器７にて霜との熱交換で温度低下し空気熱交換器７から流出した低温の冷媒は、膨張弁５で減圧されることなく膨張弁５を通過し、液冷媒熱交換器４で循環液と熱交換し、循環液から吸熱して再び圧縮機２に戻るものである。 When the forward cycle defrosting operation is performed for a predetermined time, the reverse cycle defrosting operation is then started as the defrosting operation. In the reverse cycle defrosting operation, as shown in FIG. 3, the refrigerant is used as a compressor 2, a four-way valve 3, an air heat exchanger 7, an expansion valve 5, a liquid refrigerant heat exchanger 4, a four-way valve 3, and a compressor. It is a form in which the refrigerant is circulated in the order of 2 and the refrigerant is circulated in the direction opposite to that during the heating operation (see the arrow line of the heat pump circuit 9 in FIG. 3). 18 switches the four-way valve 3 so that the flow direction of the refrigerant is opposite to the flow direction of the refrigerant during the heating operation, and controls the rotation speed of the compressor 2 to the same rotation speed during defrosting as in the normal cycle defrosting operation. At the same time, the expansion valve 5 is fully opened and the circulation pump 15 is driven at the maximum rotation speed. At this time, the high-temperature refrigerant discharged from the compressor 2 is directly supplied to the air heat exchanger 7 to melt the frost generated in the air heat exchanger 7. The low-temperature refrigerant that has dropped in temperature due to heat exchange with frost in the air heat exchanger 7 and has flowed out of the air heat exchanger 7 passes through the expansion valve 5 without being depressurized by the expansion valve 5, and is a liquid refrigerant heat exchanger. In No. 4, heat is exchanged with the circulating liquid, heat is absorbed from the circulating liquid, and the heat is returned to the compressor 2 again.

次に、特徴的な動作として、暖房運転を行っているときに空気熱交換器７に発生した霜を溶かす除霜運転が実行される場合のヒートポンプ装置１の動作について、図４のタイムチャートを用いて説明する。なお、図４中の時間ｔ０は、暖房運転が安定した後の任意の時間とする。 Next, as a characteristic operation, the time chart of FIG. 4 shows the operation of the heat pump device 1 when the defrosting operation for melting the frost generated in the air heat exchanger 7 is executed during the heating operation. It will be described using. The time t0 in FIG. 4 is an arbitrary time after the heating operation is stabilized.

四方弁３を、冷媒が圧縮機２、液冷媒熱交換器４、膨張弁５、空気熱交換器７、圧縮機２の順に循環する暖房運転時の冷媒流路となるよう制御し、圧縮機２、膨張弁５、送風ファン６を駆動させると共に、循環ポンプ１５を駆動させ、液冷媒熱交換器４にて冷媒と循環液とが熱交換されて循環液が加熱され、加熱された循環液を熱交換端末１２に供給して被空調空間を加熱する暖房運転を行っている最中に、制御装置１８が、外気温度センサ１０で検出した外気温度等から除霜開始条件が成立したと判断した場合（時間ｔ１）、制御装置１８は空気熱交換器７に発生した霜を溶かす除霜運転として所定時間の正サイクル除霜運転を開始させる（時間ｔ１〜）。この時、制御装置１８は、四方弁３は冷媒の流路の切り換えを行わず暖房運転時と同状態（冷媒が圧縮機２、液冷媒熱交換器４、膨張弁５、空気熱交換器７、圧縮機２の順に循環する状態）を継続するよう制御し、圧縮機２の回転数を予め設定された除霜時回転数に制御すると共に、膨張弁５を暖房運転時よりも所定の開度まで拡大、ここでは全開まで拡大するよう制御し、循環ポンプ１５の回転数を予め設定された除霜時回転数、ここでは暖房運転時と同回転数に制御する。循環ポンプ１５の除霜時回転数については、上述のように暖房運転時と同回転数としてもよく、暖房運転時とは異なる予め設定された所定の除霜時回転数としてもよい。 The four-way valve 3 is controlled so that the refrigerant is a refrigerant flow path during heating operation in which the refrigerant circulates in the order of the compressor 2, the liquid refrigerant heat exchanger 4, the expansion valve 5, the air heat exchanger 7, and the compressor 2. 2. The expansion valve 5 and the blower fan 6 are driven, and the circulation pump 15 is driven. The liquid refrigerant heat exchanger 4 heat-exchanges the refrigerant and the circulating liquid to heat the circulating liquid, and the heated circulating liquid. Is being supplied to the heat exchange terminal 12 to heat the air-conditioned space, and the control device 18 determines that the defrosting start condition is satisfied from the outside air temperature detected by the outside air temperature sensor 10. In this case (time t1), the control device 18 starts a positive cycle defrosting operation for a predetermined time as a defrosting operation for melting the frost generated in the air heat exchanger 7 (time t1 to). At this time, in the control device 18, the four-way valve 3 does not switch the flow path of the refrigerant and is in the same state as during the heating operation (the refrigerant is the compressor 2, the liquid refrigerant heat exchanger 4, the expansion valve 5, and the air heat exchanger 7). , The state of circulation in the order of the compressor 2) is controlled, the rotation speed of the compressor 2 is controlled to a preset rotation speed at the time of defrosting, and the expansion valve 5 is opened at a predetermined time as compared with the heating operation. It is controlled to expand to a degree, here to fully open, and the rotation speed of the circulation pump 15 is controlled to a preset rotation speed during defrosting, here the same rotation speed as during heating operation. The rotation speed of the circulation pump 15 during defrosting may be the same as that during the heating operation as described above, or may be a preset predetermined rotation speed during defrosting that is different from that during the heating operation.

前記正サイクル除霜運転時は、圧縮機２から吐出された高温の冷媒は、液冷媒熱交換器４で循環液と熱交換して循環液に放熱し、液冷媒熱交換器４を流出した後に膨張弁５を通過して空気熱交換器７に供給され、空気熱交換器７の除霜が行われるものであり、この正サイクル除霜運転時は、膨張弁５の開度を所定の開度である全開まで拡大することで、膨張弁５では冷媒は減圧されることなく通過して、膨張弁５通過時に冷媒の温度低下がほぼ無い状態で液冷媒熱交換器４を流出した冷媒が空気熱交換器７に供給され、空気熱交換器７に発生した霜を溶かすものであり、正サイクル除霜運転の実行により、膨張弁５の開度を全開にした状態で、所定時間（時間ｔ１〜時間ｔ２）の間、ヒートポンプ回路９内に冷媒を循環させることで、、暖房運転時に低圧側で温度の低かった膨張弁５から空気熱交換器７の冷媒の流路には、暖房運転時よりも高い温度の冷媒が流れ、それにより、膨張弁５から空気熱交換器７の冷媒の流路が加熱されて温度が徐々に上昇し、ヒートポンプ回路９を循環する冷媒のうち、冷媒温度が一番低い空気熱交換器７内の冷媒の最低温度値（より正確には、膨張弁５出口から空気熱交換器７出口までの冷媒流路内の冷媒の最低温度値）も例えば、−５℃から−２℃、−２℃から０℃というように徐々に上昇していく。 During the positive cycle defrosting operation, the high-temperature refrigerant discharged from the compressor 2 exchanges heat with the circulating liquid in the liquid refrigerant heat exchanger 4 and dissipates heat to the circulating liquid, and flows out of the liquid refrigerant heat exchanger 4. Later, it passes through the expansion valve 5 and is supplied to the air heat exchanger 7, and the air heat exchanger 7 is defrosted. During this positive cycle defrosting operation, the opening degree of the expansion valve 5 is set to a predetermined value. By expanding to the fully open opening, the refrigerant passes through the expansion valve 5 without being depressurized, and the refrigerant flows out of the liquid refrigerant heat exchanger 4 with almost no temperature drop of the refrigerant when passing through the expansion valve 5. Is supplied to the air heat exchanger 7 to melt the frost generated in the air heat exchanger 7, and the expansion valve 5 is fully opened for a predetermined time by executing the normal cycle defrosting operation. By circulating the refrigerant in the heat pump circuit 9 during the time t1 to the time t2), the expansion valve 5 whose temperature was low on the low pressure side during the heating operation was heated to the flow path of the refrigerant of the air heat exchanger 7. A refrigerant having a temperature higher than that during operation flows, whereby the flow path of the refrigerant of the air heat exchanger 7 is heated from the expansion valve 5 and the temperature gradually rises, and among the refrigerants circulating in the heat pump circuit 9, the refrigerant The lowest temperature value of the refrigerant in the air heat exchanger 7 having the lowest temperature (more accurately, the lowest temperature value of the refrigerant in the refrigerant flow path from the expansion valve 5 outlet to the air heat exchanger 7 outlet) is also, for example. The temperature gradually rises from -5 ° C to -2 ° C and from -2 ° C to 0 ° C.

また、前記正サイクル除霜運転は、所定時間（時間ｔ１〜時間ｔ２）行われるものであるが、この所定時間は、図５に示すように、外気温度が−５℃以上０℃未満の場合は所定時間が１分に設定され、外気温度が−１０℃以上−５℃未満の場合は所定時間が３分に設定され、外気温度が−１０℃未満の場合は所定時間が５分に設定されるというように、前記所定時間は外気温度センサ１０の検出する外気温度に応じて変更されるものであり、詳細には、外気温度センサ１０で検出される外気温度が低いほど所定時間の長さが長く設定される。このことについて説明すると、まず、暖房運転時において空気熱交換器７は蒸発器として機能しており、空気熱交換器７では外気と冷媒とで熱交換が行われ、冷媒は外気から吸熱する関係上、冷媒温度は外気温度よりも低い温度であり、外気温度が低くなるほど、それに対応して冷媒温度も低くなる。そして、暖房運転中に正サイクル除霜運転を実行するに当たり、仮に、正サイクル除霜運転を実行する前記所定時間の長さを外気温度に関係なく一律にし、外気温度が例えば−１℃であった場合と−１０℃であった場合とで正サイクル除霜運転後の状態を比較すると、外気温度が−１℃の場合は、外気温度が−１０℃の場合と比べて空気熱交換器７内の冷媒の温度が高いので、一律に設定された所定時間正サイクル除霜運転した結果、ヒートポンプ回路９を循環する冷媒のうち、冷媒温度が一番低い空気熱交換器７内の冷媒の最低温度値も上昇し、正サイクル除霜運転後の逆サイクル除霜運転が開始された際に、空気熱交換器７から流出されて液冷媒熱交換器４内に流入される冷媒の温度を、液冷媒熱交換器４内の循環液を凍結させないような温度まで上昇させることができる。一方、外気温度が−１０℃の場合は、外気温度が−１℃の場合と比べて、もともとの冷媒温度が低いため、一律に設定された所定時間正サイクル除霜運転させたとしても、正サイクル除霜運転後の逆サイクル除霜運転が開始された際に液冷媒熱交換器４内の循環液を凍結させないような温度まで上昇させることができずに、循環液を凍結させてしまうおそれがある。 Further, the positive cycle defrosting operation is performed for a predetermined time (time t1 to time t2), and this predetermined time is when the outside air temperature is −5 ° C. or higher and lower than 0 ° C. as shown in FIG. Is set to 1 minute when the outside air temperature is -10 ° C or higher and less than -5 ° C, 3 minutes when the outside air temperature is less than -10 ° C, and 5 minutes when the outside air temperature is less than -10 ° C. The predetermined time is changed according to the outside air temperature detected by the outside air temperature sensor 10. Specifically, the lower the outside air temperature detected by the outside air temperature sensor 10, the longer the predetermined time. Is set longer. To explain this, first, the air heat exchanger 7 functions as an evaporator during the heating operation, and in the air heat exchanger 7, heat exchange is performed between the outside air and the refrigerant, and the refrigerant absorbs heat from the outside air. Above, the refrigerant temperature is lower than the outside air temperature, and the lower the outside air temperature, the lower the refrigerant temperature correspondingly. Then, in executing the positive cycle defrosting operation during the heating operation, the length of the predetermined time for executing the positive cycle defrosting operation is made uniform regardless of the outside air temperature, and the outside air temperature is, for example, -1 ° C. Comparing the state after the positive cycle defrosting operation between the case where the temperature was -10 ° C and the case where the temperature was -10 ° C, when the outside air temperature was -1 ° C, the air heat exchanger 7 was compared with the case where the outside air temperature was -10 ° C. Since the temperature of the refrigerant inside is high, as a result of the positive cycle defrosting operation for a predetermined time set uniformly, the lowest of the refrigerants in the air heat exchanger 7 having the lowest refrigerant temperature among the refrigerants circulating in the heat pump circuit 9 The temperature value also rises, and when the reverse cycle defrosting operation after the normal cycle defrosting operation is started, the temperature of the refrigerant flowing out of the air heat exchanger 7 and flowing into the liquid refrigerant heat exchanger 4 is determined. The temperature can be raised to a temperature at which the circulating liquid in the liquid refrigerant heat exchanger 4 is not frozen. On the other hand, when the outside air temperature is -10 ° C, the original refrigerant temperature is lower than when the outside air temperature is -1 ° C. When the reverse cycle defrosting operation after the cycle defrosting operation is started, the circulating liquid in the liquid refrigerant heat exchanger 4 cannot be raised to a temperature that does not freeze, and the circulating liquid may be frozen. There is.

上述の比較例のうち、低い方の外気温度（上記例では−１０℃）を基準として所定時間の長さを一律に設定することも考えられるが、その場合、外気温度が高いとき（上記例では−１℃）には、過剰に正サイクル除霜運転を行うこととなり、それでは無駄な放熱ロスが発生してしまう。よって、所定時間の長さは外気温度に応じて設定されるのがよく、外気温度が低いほど正サイクル除霜運転を実行する時間を長く設定するのがよいということになる。なお、図５に示した外気温度と所定時間との対応関係は一例であるが、予め実験を行うことで、正サイクル除霜運転終了時に、ヒートポンプ回路９を循環する冷媒のうち、冷媒温度が一番低い空気熱交換器７内の冷媒の最低温度値が、循環液を凍結させないような温度まで上昇させることができる時間を、外気温度に応じて定めたものであり、図５の外気温度と所定時間との対応関係を示したデータテーブルは制御装置１８に予め記憶されている。また、所定時間は、除霜開始条件が成立したと判断したタイミング（時間ｔ１）で、外気温度センサ１０の検出する外気温度に基づき制御装置１８が設定するものである。 Of the above comparative examples, it is conceivable to uniformly set the length of the predetermined time based on the lower outside air temperature (-10 ° C. in the above example), but in that case, when the outside air temperature is high (the above example). Then, at -1 ° C), the positive cycle defrosting operation is excessively performed, which causes unnecessary heat dissipation loss. Therefore, the length of the predetermined time is preferably set according to the outside air temperature, and the lower the outside air temperature, the longer the time for executing the positive cycle defrosting operation is set. The correspondence between the outside air temperature and the predetermined time shown in FIG. 5 is an example, but by conducting an experiment in advance, the refrigerant temperature among the refrigerants circulating in the heat pump circuit 9 at the end of the normal cycle defrosting operation is changed. The time during which the minimum temperature value of the refrigerant in the lowest air heat exchanger 7 can be raised to a temperature that does not freeze the circulating fluid is determined according to the outside air temperature, and the outside air temperature in FIG. 5 is determined. A data table showing the correspondence between the temperature and the predetermined time is stored in the control device 18 in advance. Further, the predetermined time is set by the control device 18 based on the outside air temperature detected by the outside air temperature sensor 10 at the timing (time t1) when it is determined that the defrosting start condition is satisfied.

そして、前記正サイクル除霜運転の実行開始から所定時間（時間ｔ１〜時間ｔ２）が経過したと制御装置１８が判断すると正サイクル除霜運転を終了し、次に、空気熱交換器７に発生した霜を溶かす除霜運転として逆サイクル除霜運転を開始させる（時間ｔ２〜）。このとき、制御装置１８は圧縮機２の駆動を停止させ、四方弁３を、冷媒が圧縮機２、空気熱交換器７、膨張弁５、液冷媒熱交換器４、圧縮機２の順に循環する暖房運転時とは逆転した冷媒流路となるように切り換える（時間ｔ２）。また、このときの膨張弁５の開度は全開であり、循環ポンプ１５の回転数は除霜時回転数を維持している。 Then, when the control device 18 determines that a predetermined time (time t1 to time t2) has elapsed from the start of execution of the normal cycle defrosting operation, the normal cycle defrosting operation is terminated, and then the air heat exchanger 7 is generated. The reverse cycle defrosting operation is started as the defrosting operation for melting the frost (time t2-). At this time, the control device 18 stops the drive of the compressor 2, and the refrigerant circulates through the four-way valve 3 in the order of the compressor 2, the air heat exchanger 7, the expansion valve 5, the liquid refrigerant heat exchanger 4, and the compressor 2. It is switched so that the refrigerant flow path is reversed from that during the heating operation (time t2). Further, the opening degree of the expansion valve 5 at this time is fully open, and the rotation speed of the circulation pump 15 maintains the rotation speed at the time of defrosting.

そして、制御装置１８は、圧縮機２の吐出側（高圧側）と吸込側（低圧側）の差圧をなくして圧縮機２等の機能部品を次の起動時に安全に起動させるために、時間ｔ２〜時間ｔ３の一定時間圧縮機２を停止させ、その後、圧縮機２の回転数を予め設定された除霜時回転数に設定して駆動を開始させると共に、循環ポンプ１５を最大回転数で駆動させる（時間ｔ３〜時間ｔ４）。このとき、圧縮機２から吐出された高温の冷媒が、直接的に空気熱交換器７に供給され空気熱交換器７に発生した霜を溶かし、空気熱交換器７から流出した冷媒は、膨張弁５で減圧されることなく膨張弁５を通過し、液冷媒熱交換器４で循環液と熱交換して循環液から吸熱し、再び圧縮機２に戻るものである。 Then, the control device 18 eliminates the differential pressure between the discharge side (high pressure side) and the suction side (low pressure side) of the compressor 2 and takes time to safely start the functional parts such as the compressor 2 at the next startup. The compressor 2 is stopped for a certain period of time t2 to time t3, and then the rotation speed of the compressor 2 is set to a preset rotation speed at the time of defrosting to start driving, and the circulation pump 15 is operated at the maximum rotation speed. Drive (time t3 to time t4). At this time, the high-temperature refrigerant discharged from the compressor 2 is directly supplied to the air heat exchanger 7 to melt the frost generated in the air heat exchanger 7, and the refrigerant flowing out from the air heat exchanger 7 expands. It passes through the expansion valve 5 without being depressurized by the valve 5, exchanges heat with the circulating liquid in the liquid refrigerant heat exchanger 4, absorbs heat from the circulating liquid, and returns to the compressor 2 again.

この逆サイクル除霜運転時は、空気熱交換器７から流出した冷媒は膨張弁５側を回って液冷媒熱交換器４に循環されるが、逆サイクル除霜運転実行前の正サイクル除霜運転にて、冷媒の最低温度値を液冷媒熱交換器４内の循環液を凍結させないような温度まで上昇させるので、逆サイクル除霜運転時に、空気熱交換器７から流出して膨張弁５側から回ってきた冷媒が液冷媒熱交換器４に流入しても、液冷媒熱交換器４内の循環液が凍結することはなく、循環液の凍結による液冷媒熱交換器４の破損もないものである。 During this reverse cycle defrosting operation, the refrigerant flowing out from the air heat exchanger 7 goes around the expansion valve 5 side and is circulated to the liquid refrigerant heat exchanger 4, but the positive cycle defrosting before the reverse cycle defrosting operation is executed. During operation, the minimum temperature value of the refrigerant is raised to a temperature at which the circulating liquid in the liquid refrigerant heat exchanger 4 is not frozen. Therefore, during the reverse cycle defrosting operation, it flows out from the air heat exchanger 7 and the expansion valve 5 Even if the refrigerant flowing from the side flows into the liquid refrigerant heat exchanger 4, the circulating liquid in the liquid refrigerant heat exchanger 4 does not freeze, and the liquid refrigerant heat exchanger 4 may be damaged due to the freezing of the circulating liquid. There is no such thing.

また、逆サイクル除霜運転時は、循環ポンプ１５の回転数を最大回転数とすることで、循環回路１３側の熱を液冷媒熱交換器４を介して循環液側から冷媒側に積極的に与えて空気熱交換器７の除霜に利用し、除霜運転が行われる時間を短縮することができるものである。 Further, during the reverse cycle defrosting operation, by setting the rotation speed of the circulation pump 15 to the maximum rotation speed, the heat on the circulation circuit 13 side is positively transferred from the circulation liquid side to the refrigerant side via the liquid refrigerant heat exchanger 4. It can be used for defrosting the air heat exchanger 7 to shorten the time during which the defrosting operation is performed.

そして、前記逆サイクル除霜運転を行っているときに、制御装置１８が、冷媒温度センサ１１で検出する空気熱交換器７を流通してきた冷媒の温度から除霜終了条件が成立したと判断すると、圧縮機２の駆動を停止させ、循環ポンプ１５の回転数を最大回転数から除霜時回転数で駆動するように制御し（時間ｔ４）、圧縮機２の吐出側（高圧側）と吸込側（低圧側）の差圧をなくして圧縮機２等の機能部品を次の起動時に安全に起動させるために、時間ｔ４〜時間ｔ５の一定時間圧縮機２を停止させ、逆サイクル除霜運転を終了させて除霜運転を完了させ、その後、制御装置１８は、四方弁３を、冷媒が圧縮機２、液冷媒熱交換器４、膨張弁５、空気熱交換器７、圧縮機２の順に循環する暖房運転時の冷媒流路となるように切り換え、圧縮機２の駆動を開始させると共に、膨張弁５の開度を全開から暖房運転時における開度に戻し、循環ポンプ１５の回転数を除霜時回転数から暖房運転時における回転数に戻して、暖房運転を再開させるものである（時間ｔ５〜）。 Then, when the reverse cycle defrosting operation is being performed, the control device 18 determines that the defrosting end condition is satisfied from the temperature of the refrigerant flowing through the air heat exchanger 7 detected by the refrigerant temperature sensor 11. , The drive of the compressor 2 is stopped, the rotation speed of the circulation pump 15 is controlled to be driven from the maximum rotation speed to the rotation speed at the time of defrosting (time t4), and the suction side (high pressure side) of the compressor 2 and the suction side. In order to eliminate the differential pressure on the side (low pressure side) and safely start the functional parts such as the compressor 2 at the next startup, the compressor 2 is stopped for a certain period of time t4 to time t5, and the reverse cycle defrosting operation is performed. After that, the control device 18 uses the four-way valve 3 as the compressor, the liquid refrigerant heat exchanger 4, the expansion valve 5, the air heat exchanger 7, and the compressor 2. The compressor is switched to the refrigerant flow path that circulates in order during the heating operation, the compressor 2 is started to be driven, the opening degree of the expansion valve 5 is returned from the fully opened state to the opening degree during the heating operation, and the number of rotations of the circulation pump 15 is increased. Is returned from the number of revolutions during defrosting to the number of revolutions during heating operation, and the heating operation is restarted (time t5).

以上説明したように、本実施形態では、暖房運転中に除霜開始条件が成立した場合に、正サイクル除霜運転を所定時間実行してから逆サイクル除霜運転を行うようにしている。仮に、暖房運転中に除霜開始条件が成立した場合に、いきなり逆サイクル除霜を行ってしまうと、暖房運転時に蒸発器として機能していた空気熱交換器７内に保有された低温の冷媒（マイナス域の温度の冷媒）が、何ら温度上昇することなく低温のまま、空気熱交換器７から膨張弁５側を回って液冷媒熱交換器４に流れ込み、その結果、液冷媒熱交換器４は急速に冷却され、液冷媒熱交換器４内で低温の冷媒と熱交換された循環液が凍結する可能性があり、循環液の凍結によって液冷媒熱交換器４が破損するおそれがあったが、正サイクル除霜運転を所定時間実行してから逆サイクル除霜運転を行うようにしたことで、所定時間の正サイクル除霜運転により、ヒートポンプ回路９を循環する冷媒のうち、冷媒温度が一番低い空気熱交換器７内の冷媒の最低温度値を、循環液が凍結しない温度に上昇させ、それから逆サイクル除霜運転を行うので、逆サイクル除霜運転時に、空気熱交換器７から流出して膨張弁５側から回ってきた冷媒が液冷媒熱交換器４に流入しても、液冷媒熱交換器４内の循環液が凍結することはなく、循環液の凍結による液冷媒熱交換器４の破損もないものである。さらに、正サイクル除霜運転を所定時間実行してヒートポンプ回路９を循環する冷媒の最低温度値を高めてから、逆サイクル除霜運転を行うようにしたことで、逆サイクル除霜運転時に液冷媒熱交換器４にて冷媒と熱交換される循環回路１３側の循環液の温度低下が、逆サイクル除霜運転のみを行った場合よりも軽減され、暖房感の低下を緩和することができるものである。 As described above, in the present embodiment, when the defrosting start condition is satisfied during the heating operation, the normal cycle defrosting operation is executed for a predetermined time, and then the reverse cycle defrosting operation is performed. If the defrosting start condition is satisfied during the heating operation and the reverse cycle defrosting is suddenly performed, the low-temperature refrigerant held in the air heat exchanger 7 that was functioning as an evaporator during the heating operation. (Negative temperature refrigerant) flows from the air heat exchanger 7 to the liquid refrigerant heat exchanger 4 from the air heat exchanger 7 around the expansion valve 5 side without any temperature rise, and as a result, the liquid refrigerant heat exchanger. 4 is cooled rapidly, and the circulating fluid that has been heat-exchanged with the low-temperature refrigerant in the liquid refrigerant heat exchanger 4 may freeze, and the liquid refrigerant heat exchanger 4 may be damaged due to the freezing of the circulating fluid. However, since the normal cycle defrosting operation is executed for a predetermined time and then the reverse cycle defrosting operation is performed, the refrigerant temperature of the refrigerant circulating in the heat pump circuit 9 due to the positive cycle defrosting operation for a predetermined time. The lowest temperature value of the refrigerant in the air heat exchanger 7 is raised to a temperature at which the circulating fluid does not freeze, and then the reverse cycle defrosting operation is performed. Therefore, during the reverse cycle defrosting operation, the air heat exchanger 7 Even if the refrigerant flowing out from the expansion valve 5 and flowing into the liquid refrigerant heat exchanger 4 does not freeze, the circulating liquid in the liquid refrigerant heat exchanger 4 does not freeze, and the liquid refrigerant due to the freezing of the circulating liquid does not freeze. The heat exchanger 4 is not damaged. Further, the reverse cycle defrosting operation is performed after the normal cycle defrosting operation is executed for a predetermined time to raise the minimum temperature value of the refrigerant circulating in the heat pump circuit 9, so that the liquid refrigerant is operated during the reverse cycle defrosting operation. The temperature drop of the circulating fluid on the circulation circuit 13 side, which exchanges heat with the refrigerant in the heat exchanger 4, is reduced as compared with the case where only the reverse cycle defrosting operation is performed, and the deterioration of the heating feeling can be alleviated. Is.

また、本実施形態では、正サイクル除霜運転を実行する所定時間の長さを、外気温度が低いほど長くするようにしているが、これは、暖房運転時に空気熱交換器７内の冷媒は外気から吸熱する関係上、外気温度センサ１０で検出される外気温度が低いほど空気熱交換器７内の冷媒温度も低いので、暖房運転時にヒートポンプ回路９を循環する冷媒のうち、冷媒温度が一番低い空気熱交換器７内の冷媒の最低温度値を、正サイクル除霜運転を行うことによって、液冷媒熱交換器４内の循環液が凍結しない温度値まで上昇させるのに必要な時間が変わってくることによるものである。よって、正サイクル除霜運転を実行する所定時間の長さを、外気温度が低いほど長くするようにしたことで、外気温度に対応する空気熱交換器７内の冷媒温度に合わせた時間分、正サイクル除霜運転を行うので、暖房運転時にヒートポンプ回路９を循環する冷媒のうち、冷媒温度が一番低い空気熱交換器７内の冷媒の最低温度値を、正サイクル除霜運転により循環液が凍結しない温度まで適切に上昇させることができ、正サイクル除霜運転後の逆サイクル除霜運転が行われたときに、液冷媒熱交換器４に循環液が凍結するような温度の冷媒を流入させることがないものである。 Further, in the present embodiment, the length of the predetermined time for executing the positive cycle defrosting operation is made longer as the outside air temperature is lower, but this is because the refrigerant in the air heat exchanger 7 is used during the heating operation. Since heat is absorbed from the outside air, the lower the outside air temperature detected by the outside air temperature sensor 10, the lower the refrigerant temperature in the air heat exchanger 7. Therefore, among the refrigerants circulating in the heat pump circuit 9 during the heating operation, the refrigerant temperature is one. The time required to raise the minimum temperature value of the refrigerant in the lowest air heat exchanger 7 to a temperature value at which the circulating liquid in the liquid refrigerant heat exchanger 4 does not freeze by performing a positive cycle defrosting operation. It is due to change. Therefore, by making the length of the predetermined time for executing the positive cycle defrosting operation longer as the outside air temperature is lower, the time corresponding to the outside air temperature is adjusted to the refrigerant temperature in the air heat exchanger 7. Since the normal cycle defrosting operation is performed, the lowest temperature value of the refrigerant in the air heat exchanger 7 having the lowest refrigerant temperature among the refrigerants circulating in the heat pump circuit 9 during the heating operation is set to the circulating fluid by the normal cycle defrosting operation. Can be appropriately raised to a temperature at which the refrigerant does not freeze, and when the reverse cycle defrosting operation is performed after the normal cycle defrosting operation, the liquid refrigerant heat exchanger 4 is provided with a refrigerant having a temperature at which the circulating liquid freezes. It does not flow in.

さらに、逆サイクル除霜運時は、循環ポンプ１５の回転数を最大回転数として駆動させることで、循環回路１３側の熱を液冷媒熱交換器４を介して循環液側から冷媒側に積極的に与えて空気熱交換器７の除霜に利用し、除霜運転が行われる時間を短縮することができるものである。 Further, during the reverse cycle defrosting operation, the heat of the circulation circuit 13 side is positively transferred from the circulating liquid side to the refrigerant side via the liquid refrigerant heat exchanger 4 by driving the circulation pump 15 as the maximum rotation speed. It can be given as a target and used for defrosting the air heat exchanger 7, and the time during which the defrosting operation is performed can be shortened.

なお、本発明は先に説明した一実施形態に限定されるものでなく、本実施形態では、暖房装置のみならず冷房装置としても使用可能なヒートポンプ装置において、暖房運転時に本発明の除霜運転を適用したが、暖房装置としてのみ使用可能なヒートポンプ装置において、その暖房運転時に本発明の除霜運転を適用してもよいものである。 The present invention is not limited to the one embodiment described above. In the present embodiment, in a heat pump device that can be used not only as a heating device but also as a cooling device, the defrosting operation of the present invention is performed during the heating operation. However, in a heat pump device that can be used only as a heating device, the defrosting operation of the present invention may be applied during the heating operation.

また、本実施形態では、正サイクル除霜運転を所定時間実行して、暖房運転時にヒートポンプ回路９を循環する冷媒のうち、冷媒温度が一番低い空気熱交換器７内の冷媒の最低温度値を、正サイクル除霜運転により循環液が凍結しない温度まで上昇させてから、その後に逆サイクル除霜運転を行うようにしたが、正サイクル除霜運転時を、冷媒温度センサ１１で検出される冷媒温度が循環液が凍結しない温度に上昇するまで正サイクル除霜運転を実行して、その後に逆サイクル除霜運転を行うようにしてもよく、この場合でも、先に説明した本実施形態と同様に、正サイクル除霜運転により、ヒートポンプ回路９を循環する冷媒のうち、冷媒温度が一番低い空気熱交換器７内の冷媒の最低温度値を、循環液が凍結しない温度に上昇させ、それから逆サイクル除霜運転を行うので、逆サイクル除霜運転時に、空気熱交換器７から流出して膨張弁５側から回ってきた冷媒が液冷媒熱交換器４に流入しても、液冷媒熱交換器４内の循環液が凍結することはなく、循環液の凍結による液冷媒熱交換器４の破損もないという効果を発揮することができるものである。 Further, in the present embodiment, the normal cycle defrosting operation is executed for a predetermined time, and among the refrigerants circulating in the heat pump circuit 9 during the heating operation, the lowest temperature value of the refrigerant in the air heat exchanger 7 having the lowest refrigerant temperature. Was raised to a temperature at which the circulating fluid does not freeze by the normal cycle defrosting operation, and then the reverse cycle defrosting operation was performed. However, the normal cycle defrosting operation is detected by the refrigerant temperature sensor 11. The normal cycle defrosting operation may be performed until the refrigerant temperature rises to a temperature at which the circulating fluid does not freeze, and then the reverse cycle defrosting operation may be performed. Similarly, by the positive cycle defrosting operation, the minimum temperature value of the refrigerant in the air heat exchanger 7 having the lowest refrigerant temperature among the refrigerants circulating in the heat pump circuit 9 is raised to a temperature at which the circulating liquid does not freeze. Then, since the reverse cycle defrosting operation is performed, even if the refrigerant flowing out of the air heat exchanger 7 and flowing from the expansion valve 5 side flows into the liquid refrigerant heat exchanger 4 during the reverse cycle defrosting operation, the liquid refrigerant The effect that the circulating liquid in the heat exchanger 4 does not freeze and the liquid refrigerant heat exchanger 4 is not damaged due to the freezing of the circulating liquid can be exhibited.

２圧縮機
３四方弁
４液冷媒熱交換器
５膨張弁
７空気熱交換器
９ヒートポンプ回路
１０外気温度センサ
１３循環回路
１５循環ポンプ
１８制御装置 2 Compressor 3 Four-way valve 4 Liquid refrigerant heat exchanger 5 Expansion valve 7 Air heat exchanger 9 Heat pump circuit 10 Outside air temperature sensor 13 Circulation circuit 15 Circulation pump 18 Control device

Claims

A compressor for compressing the refrigerant, a flow path switching means, a liquid refrigerant heat exchanger for heat exchange between the circulating liquid and the refrigerant, an expansion valve, and an air heat exchanger for heat exchange between the outside air and the refrigerant. A heat pump circuit that has and circulates the refrigerant,
A circulation circuit having a liquid refrigerant heat exchanger and a circulation pump for circulating the circulating liquid in the liquid refrigerant heat exchanger, and circulating the circulating liquid.
Equipped with a control device to control the operation
In a heat pump device that operates the heat pump circuit and drives the circulation pump to perform a heating operation for heating the circulating liquid.
When the control device executes a defrosting operation for melting the frost generated in the air heat exchanger during the heating operation, the flow direction of the refrigerant becomes the same as the flow direction of the refrigerant during the heating operation. The forward cycle defrosting operation in which the refrigerant is circulated by controlling the flow path switching means and expanding the opening degree of the expansion valve as compared with the heating operation is performed by the refrigerant in the air heat exchanger. After the operation is performed until the temperature of the circulating fluid rises to a temperature at which the circulating fluid does not freeze, the flow path switching means is switched so that the flow direction of the refrigerant is opposite to the flow direction of the refrigerant during the heating operation. The reverse cycle defrosting operation in which the refrigerant is circulated is executed, and when the predetermined defrosting end condition is satisfied during the execution of the reverse cycle defrosting operation, the reverse cycle defrosting operation is terminated and the heating operation is performed. A heat pump device characterized by being able to restart.

A refrigerant temperature sensor is provided in the refrigerant pipe from the expansion valve to the air heat exchanger.
The heat pump according to claim 1, wherein the control device executes the positive cycle defrosting operation until the refrigerant temperature detected by the refrigerant temperature sensor rises to a temperature at which the circulating fluid does not freeze. Device.