JP2014070855A

JP2014070855A - Heat pump device

Info

Publication number: JP2014070855A
Application number: JP2012219267A
Authority: JP
Inventors: Hayahiko Takagi; 速彦高城; Tomokazu Kobayashi; 友和小林; Yuto Sakai; 祐人酒井; Yasushi Osagawa; 康司長川
Original assignee: Sanden Corp
Current assignee: Sanden Corp
Priority date: 2012-10-01
Filing date: 2012-10-01
Publication date: 2014-04-21

Abstract

PROBLEM TO BE SOLVED: To improve a heat pump device so that a defrost operation is promptly finished.SOLUTION: A heat pump device is constituted by comprising: a heat pump unit in which a cooling medium circulates in order of a compressor, a heat exchanger, an expansion valve and an evaporator; a tank which stores a heating medium subjected to heat exchange by the heat exchanger; a circulation pump which makes the heating medium of the tank pass through a load to be circulated; and a defrost control unit which executes a defrost operation for circulating the cooling medium as hot gas in a state that the expansion valve is fully opened, an evaporation operation of the evaporator is stopped, and heating medium circulation by the circulation pump is stopped (S1), when a defrost starting condition is established (S0). The defrost control unit controls the circulation pump so that the cooling medium and the heating medium perform the heat exchange by the heat exchanger (S4) when the cooling medium and the heating medium become predetermined temperature relation during the defrost operation (S2). Temperature is maintained by collecting heat of the heating medium to the cooling medium to promptly finish the defrost operation.

Description

暖房用のヒートポンプ装置に関する技術が以下に開示される。 The technique regarding the heat pump apparatus for heating is disclosed below.

近年、冷媒を循環させる冷凍サイクルを、暖房用の温水（熱媒）を生成するヒートポンプユニットとして利用するヒートポンプ装置が普及している。この種のヒートポンプ装置では、外気から冷媒へ採熱する蒸発器で霜が成長し、熱交換能力の低下を招くので、その霜を取り除くデフロスト運転（除霜運転）が所定のタイミングで実行される。このデフロスト運転では、例えば特許文献１に開示されるように、ヒートポンプユニットの冷凍サイクルを逆転させて冷媒を循環させ、冷媒をホットガスとして蒸発器へ送り込むことで除霜が行われる。 2. Description of the Related Art In recent years, heat pump devices that use a refrigeration cycle that circulates refrigerant as a heat pump unit that generates hot water (heating medium) for heating have become widespread. In this type of heat pump device, frost grows in the evaporator that collects heat from the outside air to the refrigerant, leading to a decrease in heat exchange capacity. Therefore, a defrost operation (defrost operation) for removing the frost is performed at a predetermined timing. . In this defrost operation, for example, as disclosed in Patent Document 1, defrosting is performed by reversing the refrigeration cycle of the heat pump unit to circulate the refrigerant and sending the refrigerant as hot gas to the evaporator.

特開２０１１−１２７８７８号公報JP 2011-127878 A

デフロスト運転は、暖房運転中に所定の条件が成立すると実行され、その間は温水循環が止められて暖房が止まるので、極力短く終わらせる方が好ましい。特許文献１のデフロスト運転では、最短で、蒸発器の入り口での冷媒温度が第２の基準温度（５℃）を越えた場合に除霜処理終了と判断される（特許文献１の段落００２９）。しかし、氷点下の外気温度では、蒸発器までホットガスが到達する間に配管からの放熱もあり、霜を溶かすために必要な融解潜熱が多く、ホットガスの温度低下が速い。このため、デフロスト運転終了の条件が成立するのに時間がかかる。この点に着目すると、ヒートポンプ装置において、デフロスト運転を早く終了させるべく改善が望まれる。 The defrost operation is executed when a predetermined condition is satisfied during the heating operation, and during that period, the hot water circulation is stopped and the heating is stopped. Therefore, it is preferable to end the defrost operation as short as possible. In the defrost operation of Patent Document 1, it is determined that the defrosting process is completed when the refrigerant temperature at the inlet of the evaporator exceeds the second reference temperature (5 ° C.) in the shortest time (paragraph 0029 of Patent Document 1). . However, at outside air temperature below freezing point, there is also heat radiation from the piping while hot gas reaches the evaporator, so there is a lot of latent heat of melting required to melt frost, and the temperature drop of hot gas is fast. For this reason, it takes time for the defrost operation termination condition to be satisfied. When paying attention to this point, in the heat pump device, an improvement is desired so that the defrosting operation can be finished early.

当課題を解決するべく、圧縮機、熱媒−冷媒熱交換器、膨張弁及び蒸発器の順に冷媒が循環するヒートポンプユニットと、前記熱媒−冷媒熱交換器で熱交換した熱媒を貯留するタンクと、前記タンクの熱媒を負荷へ通し、前記熱媒−冷媒熱交換器へ循環させる循環ポンプと、を含んで構成されるヒートポンプ装置に関し、次の態様を提案する。 In order to solve this problem, a heat pump unit in which refrigerant circulates in the order of a compressor, a heat medium-refrigerant heat exchanger, an expansion valve, and an evaporator, and a heat medium that exchanges heat with the heat medium-refrigerant heat exchanger are stored. The following aspect is proposed regarding the heat pump apparatus comprised including a tank and the circulation pump which lets the heating medium of the said tank pass to a load, and circulates to the said heating medium-refrigerant heat exchanger.

第１の態様では、デフロスト開始条件の成立を判断し、デフロスト開始条件が成立したときに、前記膨張弁を全開にし且つ前記蒸発器の蒸発動作を止めると共に前記循環ポンプによる熱媒循環を止めた状態で前記冷媒を循環させるデフロスト運転を実行するデフロスト制御ユニット、を含み、
前記デフロスト制御ユニットが、前記デフロスト運転中に前記冷媒及び前記熱媒が所定の温度関係になると、前記熱媒−冷媒熱交換器で前記冷媒と前記熱媒が熱交換するように、前記循環ポンプを制御する。 In the first aspect, it is determined whether the defrost start condition is satisfied, and when the defrost start condition is satisfied, the expansion valve is fully opened, the evaporation operation of the evaporator is stopped, and the heat medium circulation by the circulation pump is stopped. A defrost control unit for performing a defrost operation for circulating the refrigerant in a state,
When the defrost control unit has a predetermined temperature relationship between the refrigerant and the heat medium during the defrost operation, the circulation pump is configured to exchange heat between the refrigerant and the heat medium in the heat medium-refrigerant heat exchanger. To control.

第２の態様では、前記熱媒を、前記負荷を通さずに前記熱媒−冷媒熱交換器へ戻すために、開閉可能な負荷迂回路と、デフロスト開始条件が成立したときに、前記膨張弁を全開にし且つ前記蒸発器の蒸発動作を止めると共に前記循環ポンプによる熱媒循環を止めた状態で前記冷媒を循環させるデフロスト運転を実行するデフロスト制御ユニットと、を含み、
前記デフロスト制御ユニットが、前記デフロスト運転中に前記冷媒及び前記熱媒が所定の温度関係になると、前記熱媒−冷媒熱交換器で前記冷媒と前記熱媒が熱交換するように、前記循環ポンプを制御すると共に前記負荷迂回路を開通させる。 In the second aspect, in order to return the heat medium to the heat medium-refrigerant heat exchanger without passing through the load, when the open / close load detour and a defrost start condition are satisfied, the expansion valve A defrost control unit that performs a defrost operation in which the refrigerant is circulated in a state where the evaporator is fully opened and the evaporation operation of the evaporator is stopped and the heat medium circulation by the circulation pump is stopped.
When the defrost control unit has a predetermined temperature relationship between the refrigerant and the heat medium during the defrost operation, the circulation pump is configured to exchange heat between the refrigerant and the heat medium in the heat medium-refrigerant heat exchanger. And the load bypass circuit is opened.

第３の態様では、前記負荷から戻る前記熱媒を、前記熱媒−冷媒熱交換器を通さずに前記タンクへ送るために、開閉可能な熱交換器迂回路と、デフロスト開始条件の成立を判断し、デフロスト開始条件が成立したときに、前記膨張弁を全開にし且つ前記蒸発器の蒸発動作を止めると共に前記熱交換器迂回路を開通させた状態で前記冷媒を循環させるデフロスト運転を実行するデフロスト制御ユニットと、を含み、
前記デフロスト制御ユニットが、前記デフロスト運転中に前記冷媒及び前記熱媒が所定の温度関係になると、前記熱媒−冷媒熱交換器で前記冷媒と前記熱媒が熱交換するように、前記熱交換器迂回路を閉鎖する。 In a third aspect, in order to send the heat medium returning from the load to the tank without passing through the heat medium-refrigerant heat exchanger, a heat exchanger detour that can be opened and closed and a defrost start condition are established. When the defrost start condition is satisfied, a defrost operation is performed in which the expansion valve is fully opened, the evaporation operation of the evaporator is stopped, and the refrigerant is circulated in a state where the heat exchanger bypass is opened. A defrost control unit,
When the refrigerant and the heat medium are in a predetermined temperature relationship during the defrost operation, the defrost control unit performs heat exchange so that the refrigerant and the heat medium exchange heat with the heat medium-refrigerant heat exchanger. Close the device bypass.

さらに、より具体的な態様として、低元側圧縮機、低元側熱媒−冷媒熱交換器、カスケード熱交換器、低元側膨張弁及び低元側蒸発器の順に冷媒が循環する低元側ヒートポンプユニットと、高元側圧縮機、高元側熱媒−冷媒熱交換器、高元側膨張弁及び前記カスケード熱交換器の順に冷媒が循環する高元側ヒートポンプユニットと、負荷を通して熱媒を循環させる循環ポンプを有し、前記負荷からの戻り熱媒を前記低元側熱媒−冷媒熱交換器と前記高元側熱媒−冷媒熱交換器とに分流させ、且つ、前記低元側熱媒−冷媒熱交換器及び前記高元側熱媒−冷媒熱交換器を通過した各分流熱媒を合流させて合流タンクに貯留し、該合流タンクの熱媒を前記負荷へ送り出すように構成されると共に、前記低元側熱媒−冷媒熱交換器への熱媒分流量と前記高元側熱媒−冷媒熱交換器への熱媒分流量とを調節する分流調節器を備えた負荷ユニットと、を含んで構成される二元型ヒートポンプ装置に関し、次の態様を提案する。 Furthermore, as a more specific aspect, the low-source side in which the refrigerant circulates in the order of the low-side compressor, the low-side heat medium-refrigerant heat exchanger, the cascade heat exchanger, the low-side expansion valve, and the low-side evaporator. -Side heat pump unit, high-side compressor, high-side heat medium-refrigerant heat exchanger, high-side expansion valve, and high-side heat pump unit in which the refrigerant circulates in this order, and the heat medium through the load The return heat medium from the load is divided into the low-source side heat medium-refrigerant heat exchanger and the high-source side heat medium-refrigerant heat exchanger, and the low element Each of the diverted heat media that have passed through the side heat medium-refrigerant heat exchanger and the high-source side heat medium-refrigerant heat exchanger are merged and stored in a merge tank, and the heat medium in the merge tank is sent to the load And the flow rate of the heat medium to the low-source heat medium-refrigerant heat exchanger High-stage-side heat medium - and load unit with a shunt regulator for regulating the heating medium component flow to the refrigerant heat exchanger relates to two yuan type heat pump device configured to include a proposes the following manner.

第４の態様では、デフロスト開始条件の成立を判断し、デフロスト開始条件が成立したときに、前記低元側膨張弁を全開にし且つ前記低元側蒸発器の蒸発動作を止めると共に前記循環ポンプによる熱媒循環を止めた状態で前記低元側ヒートポンプユニットの冷媒を循環させるデフロスト運転を実行するデフロスト制御ユニット、を含み、
前記デフロスト制御ユニットが、前記デフロスト運転中に前記冷媒及び前記熱媒が所定の温度関係になると、前記低元側熱媒−冷媒熱交換器で前記冷媒と前記熱媒が熱交換するように、前記分流調節器及び前記循環ポンプを制御する。 In the fourth aspect, it is determined whether the defrost start condition is satisfied, and when the defrost start condition is satisfied, the low-side expansion valve is fully opened and the evaporation operation of the low-side evaporator is stopped and the circulation pump is used. A defrost control unit for performing a defrost operation for circulating the refrigerant of the low-source side heat pump unit in a state where the heat medium circulation is stopped,
When the defrost control unit has a predetermined temperature relationship between the refrigerant and the heat medium during the defrost operation, the refrigerant and the heat medium exchange heat with the low-side heat medium-refrigerant heat exchanger. Control the shunt regulator and the circulation pump.

第５の態様では、前記熱媒を、前記負荷を通さずに前記低元側熱媒−冷媒熱交換器へ戻すために、開閉可能な負荷迂回路と、デフロスト開始条件の成立を判断し、デフロスト開始条件が成立したときに、前記低元側膨張弁を全開にし且つ前記低元側蒸発器の蒸発動作を止めると共に前記循環ポンプによる熱媒循環を止めた状態で前記低元側ヒートポンプユニットの冷媒を循環させるデフロスト運転を実行するデフロスト制御ユニットと、を含み、
前記デフロスト制御ユニットが、前記デフロスト運転中に前記冷媒及び前記熱媒が所定の温度関係になると、前記低元側熱媒−冷媒熱交換器で前記冷媒と前記熱媒が熱交換するように、前記分流調節器及び前記循環ポンプを制御すると共に前記負荷迂回路を開通させる。 In the fifth aspect, in order to return the heat medium to the low-source-side heat medium-refrigerant heat exchanger without passing through the load, it is determined whether a detour start condition can be established and a load detour that can be opened and closed, When the defrost start condition is satisfied, the low-side expansion valve is fully opened, the evaporation operation of the low-side evaporator is stopped, and the heat medium circulation by the circulation pump is stopped. A defrost control unit that performs a defrost operation for circulating the refrigerant, and
When the defrost control unit has a predetermined temperature relationship between the refrigerant and the heat medium during the defrost operation, the refrigerant and the heat medium exchange heat with the low-side heat medium-refrigerant heat exchanger. The shunt regulator and the circulation pump are controlled and the load bypass circuit is opened.

第６の態様では、前記低元側熱媒−冷媒熱交換器へ流れる熱媒を、前記低元側熱媒−冷媒熱交換器を通さずに前記合流タンクへ送るために、開閉可能な熱交換器迂回路と、デフロスト開始条件の成立を判断し、デフロスト開始条件が成立したときに、前記低元側膨張弁を全開にし且つ前記低元側蒸発器の蒸発動作を止めると共に前記熱交換器迂回路を開通させた状態で前記低元側ヒートポンプユニットの冷媒を循環させるデフロスト運転を実行するデフロスト制御ユニットと、を含み、
前記デフロスト制御ユニットが、前記デフロスト運転中に前記低元側ヒートポンプユニットの冷媒及び前記熱媒が所定の温度関係になると、前記低元側熱媒−冷媒熱交換器で前記冷媒と前記熱媒が熱交換するように、前記熱交換器迂回路を閉鎖する。 In the sixth aspect, the heat medium that flows to the low-source-side heat medium-refrigerant heat exchanger can be opened and closed in order to send the heat medium to the merging tank without passing through the low-element-side heat medium-refrigerant heat exchanger. When the defrost start condition is satisfied and the defrost start condition is satisfied, when the defrost start condition is satisfied, the low-side expansion valve is fully opened and the evaporation operation of the low-side evaporator is stopped and the heat exchanger A defrost control unit that performs a defrost operation for circulating the refrigerant of the low-source side heat pump unit in a state in which a bypass is opened, and
When the defrost control unit has a predetermined temperature relationship between the refrigerant and the heat medium in the low-side heat pump unit during the defrost operation, the low-side heat medium-refrigerant heat exchanger causes the refrigerant and the heat medium to flow. The heat exchanger bypass is closed to exchange heat.

上記提案に係るヒートポンプ装置によれば、デフロスト運転中に、ホットガスとして使用される冷媒へ熱媒の熱を回収することで、当該冷媒の温度低下を抑制することができる。すなわち、例えばデフロスト運転の後半で低下しつつある冷媒の温度を上げるように制御することができるので、デフロスト運転の時間を従来に比べて短縮することができる。 According to the heat pump device according to the above proposal, it is possible to suppress the temperature drop of the refrigerant by recovering the heat of the heat medium to the refrigerant used as the hot gas during the defrost operation. That is, for example, since it is possible to control the temperature of the refrigerant that is decreasing in the second half of the defrost operation, the time for the defrost operation can be shortened as compared with the conventional case.

ヒートポンプ装置の第１実施形態を示すブロック図。The block diagram which shows 1st Embodiment of a heat pump apparatus. ヒートポンプ装置の第２実施形態を示すブロック図。The block diagram which shows 2nd Embodiment of a heat pump apparatus. デフロスト運転制御の第１例を示すフローチャート。The flowchart which shows the 1st example of defrost operation control. デフロスト運転制御の第２例を示すフローチャート。The flowchart which shows the 2nd example of defrost operation control.

図１は、ヒートポンプ装置の第１実施形態として、ヒートポンプユニット１０、負荷ユニット２０、及び制御ユニット３０を含んで構成された単元型ヒートポンプ装置を示している。 FIG. 1 shows a unitary heat pump apparatus including a heat pump unit 10, a load unit 20, and a control unit 30 as a first embodiment of the heat pump apparatus.

ヒートポンプユニット１０は、圧縮機１１、熱媒−冷媒熱交換器１２、膨張弁１３、及び蒸発器１４を、冷媒循環路でつないで構成される冷凍回路である。冷媒には、例えばＣＯ２が使用され、該冷媒が、圧縮機１１、熱媒−冷媒熱交換器１２、膨張弁１３、及び蒸発器１４の順に循環して冷凍サイクルが実行される。すなわち冷媒は、圧縮機１１で超臨界の状態まで圧縮されて高温高圧となった後、熱媒−冷媒熱交換器１２において、負荷ユニット２０を循環する熱媒と熱交換する。次いで熱交換後の冷媒は、膨張弁１３で膨張後、ファンを備えた蒸発器１４で外気と熱交換し、圧縮機１１へ循環する。 The heat pump unit 10 is a refrigeration circuit configured by connecting a compressor 11, a heat medium-refrigerant heat exchanger 12, an expansion valve 13, and an evaporator 14 through a refrigerant circulation path. For example, CO 2 is used as the refrigerant, and the refrigerant circulates in the order of the compressor 11, the heat medium-refrigerant heat exchanger 12, the expansion valve 13, and the evaporator 14 to execute the refrigeration cycle. That is, the refrigerant is compressed to a supercritical state by the compressor 11 and becomes a high temperature and high pressure, and then heat exchange with the heat medium circulating in the load unit 20 in the heat medium-refrigerant heat exchanger 12. Next, the heat-exchanged refrigerant is expanded by the expansion valve 13, exchanges heat with the outside air in the evaporator 14 equipped with a fan, and circulates to the compressor 11.

負荷ユニット２０は、一例として、床下に通したパイプに温水を流す床暖房ユニットである。床暖房の他にも、例えば、各部屋に備えられたパネルラジエータが負荷としてあり得る。第１実施形態の負荷ユニット２０は、熱媒として温水（水）を循環させる熱媒循環路２１を備え、この熱媒循環路２１において、暖房負荷より上流側に循環ポンプ２２、下流側に膨張タンク２３が設けられる。循環ポンプ２２が熱媒を暖房負荷へ送り出して循環させ、膨張タンク２３は、熱媒循環路２１内の熱媒量を一定に保つために設けられる。また、負荷ユニット２０は、熱媒−冷媒熱交換器１２で熱交換した熱媒を貯留する所定容量のタンク２４を熱媒循環路２１に備えている。このタンク２４には、熱交換で５０℃〜７０℃ほどになる熱媒が数リットル程度貯留され、ここから循環ポンプ２２により往き熱媒が暖房負荷へ送り出される。 As an example, the load unit 20 is a floor heating unit that flows hot water through a pipe that passes under the floor. In addition to floor heating, for example, a panel radiator provided in each room may be a load. The load unit 20 of the first embodiment includes a heat medium circulation path 21 that circulates hot water (water) as a heat medium. In the heat medium circulation path 21, the circulation pump 22 is upstream of the heating load, and is expanded downstream. A tank 23 is provided. The circulation pump 22 sends the heat medium to the heating load to circulate, and the expansion tank 23 is provided to keep the amount of the heat medium in the heat medium circulation path 21 constant. Further, the load unit 20 includes a tank 24 having a predetermined capacity for storing the heat medium exchanged by the heat medium-refrigerant heat exchanger 12 in the heat medium circulation path 21. In this tank 24, about several liters of a heat medium that is about 50 ° C. to 70 ° C. is stored by heat exchange, and the forward heat medium is sent from the circulation pump 22 to the heating load.

負荷ユニット２０には、後述する各例のデフロスト運転用に、それぞれ点線で示す負荷迂回路２５や熱交換器迂回路２６を設けることが可能である。負荷迂回路２５は、暖房負荷へ送り出される往き熱媒の通る熱媒循環路２１中に挿入される三方弁２５ａを有し、この三方弁２５ａの開閉制御に従って、往き熱媒を暖房負荷へ送り出す通常の経路か、又は、暖房負荷からの戻り熱媒が通る熱媒循環路２１へ往き熱媒を迂回させ、暖房負荷を通さずに熱媒−冷媒熱交換器１２へ戻す短絡経路が選択される。熱交換器迂回路２６は、暖房負荷からの戻り熱媒の通る熱媒循環路２１中に挿入される三方弁２６ａを有し、この三方弁２６ａの開閉制御に従って、戻り熱媒を熱媒−冷媒熱交換器１２へ通す通常の経路か、又は、戻り熱媒を熱媒−冷媒熱交換器１２を通さずにタンク２４へ送る短絡経路が選択される。 The load unit 20 can be provided with a load bypass circuit 25 and a heat exchanger bypass circuit 26 indicated by dotted lines, respectively, for defrost operation of each example described later. The load bypass circuit 25 has a three-way valve 25a inserted into the heat medium circulation path 21 through which the forward heat medium sent to the heating load passes, and sends the forward heat medium to the heating load according to the opening / closing control of the three-way valve 25a. Either a normal path or a short-circuit path that returns to the heat medium-refrigerant heat exchanger 12 without passing through the heating load is selected by detouring the heat medium to the heat medium circulation path 21 through which the return heat medium from the heating load passes. The The heat exchanger detour 26 has a three-way valve 26a inserted into the heat medium circuit 21 through which the return heat medium from the heating load passes, and the return heat medium is transferred to the heat medium according to the open / close control of the three-way valve 26a. A normal path for passing through the refrigerant heat exchanger 12 or a short-circuit path for sending the return heat medium to the tank 24 without passing through the heat medium-refrigerant heat exchanger 12 is selected.

制御ユニット３０は、ＥＣＵ（電子制御ユニット）等を備え、ヒートポンプユニット１０における圧縮機１１の回転速度や膨張弁１３の開度、及び、負荷ユニット２０における循環ポンプ２２の回転速度等を制御する。制御にあたっては、外気温度センサＳａ、蒸発器温度センサＳｂ、熱交換前の圧縮冷媒温度センサＳｃ、熱交換後冷媒温度センサＳｄ、往き熱媒温度センサＳｅ、戻り熱媒温度センサＳｆ、熱交換後の熱媒温度センサＳｇによる各測定値が使用される。この制御ユニット３０は、内蔵したプログラムに従ってデフロスト制御ユニットとして機能し、後述するデフロスト運転を制御する。 The control unit 30 includes an ECU (electronic control unit) and the like, and controls the rotational speed of the compressor 11 in the heat pump unit 10, the opening degree of the expansion valve 13, the rotational speed of the circulation pump 22 in the load unit 20, and the like. In the control, outside air temperature sensor Sa, evaporator temperature sensor Sb, compressed refrigerant temperature sensor Sc before heat exchange, refrigerant temperature sensor Sd after heat exchange, forward heat medium temperature sensor Se, return heat medium temperature sensor Sf, after heat exchange Each measured value by the heat medium temperature sensor Sg is used. The control unit 30 functions as a defrost control unit according to a built-in program, and controls a defrost operation to be described later.

図２は、ヒートポンプ装置の第２実施形態として、低元側ヒートポンプユニット１００、高元側ヒートポンプユニット１１０、負荷ユニット２００、及び制御ユニット３００を含んで構成された二元型ヒートポンプ装置を示している。 FIG. 2 shows a binary heat pump device that includes a low-source heat pump unit 100, a high-source heat pump unit 110, a load unit 200, and a control unit 300 as a second embodiment of the heat pump device. .

低元側ヒートポンプユニット１００は、低元側圧縮機１０１、低元側熱媒−冷媒熱交換器１０２、カスケード熱交換器１０３、低元側膨張弁１０４、及び低元側蒸発器１０５を、冷媒循環路でつないで構成される冷凍回路である。冷媒には、例えばＣＯ_２が使用され、該冷媒が、低元側圧縮機１０１、低元側熱媒−冷媒熱交換器１０２、カスケード熱交換器１０３、低元側膨張弁１０４、及び低元側蒸発器１０５の順に循環して冷凍サイクルが実行される。すなわち冷媒は、低元側圧縮機１０１で超臨界の状態まで圧縮されて高温高圧となった後、低元側熱媒−冷媒熱交換器１０２において、負荷ユニット２００を循環する熱媒の低元側分流と熱交換する。次いで冷媒は、低元側熱媒−冷媒熱交換器１０２からカスケード熱交換器１０３へ流れ、熱媒との熱交換で使い切れず、外気温度よりも高く吸熱源として未だ使用可能な冷媒の熱が、高元側ヒートポンプユニット１１０の吸熱源として利用される。冷媒−冷媒熱交換器であるカスケード熱交換器１０３で熱交換した後の冷媒は、低元側膨張弁１０４で膨張後、ファンを備えた低元側蒸発器１０５で外気と熱交換し、低元側圧縮機１０１へ循環する。 The low-side heat pump unit 100 includes a low-side compressor 101, a low-side heat medium-refrigerant heat exchanger 102, a cascade heat exchanger 103, a low-side expansion valve 104, and a low-side evaporator 105. This is a refrigeration circuit connected by a circulation path. For example, CO ₂ is used as the refrigerant, and the refrigerant includes the low-side compressor 101, the low-side heat medium-refrigerant heat exchanger 102, the cascade heat exchanger 103, the low-side expansion valve 104, and the low-side compressor. The refrigeration cycle is executed by circulating in the order of the side evaporator 105. That is, the refrigerant is compressed to a supercritical state by the low-side compressor 101 and becomes high temperature and high pressure, and then the low-temperature side of the heat medium circulating in the load unit 200 in the low-side heat medium-refrigerant heat exchanger 102. Exchange heat with side branch. Next, the refrigerant flows from the low-side heat medium-refrigerant heat exchanger 102 to the cascade heat exchanger 103, is not used up for heat exchange with the heat medium, and the heat of the refrigerant that is higher than the outside air temperature and still usable as a heat absorption source It is used as a heat absorption source of the high-side heat pump unit 110. The refrigerant after heat exchange in the cascade heat exchanger 103, which is a refrigerant-refrigerant heat exchanger, expands in the low-side expansion valve 104, and then exchanges heat with the outside air in the low-side evaporator 105 having a fan. Circulate to the former compressor 101.

高元側ヒートポンプユニット１１０は、高元側圧縮機１１１、高元側熱媒−冷媒熱交換器１１２、高元側膨張弁１１３、そしてカスケード熱交換器１０３を、冷媒循環路でつないで構成される冷凍回路である。冷媒には、低元側と同じくＣＯ_２が使用され、該冷媒が、高元側圧縮機１１１、高元側熱媒−冷媒熱交換器１１２、高元側膨張弁１１３及びカスケード熱交換器１０３の順に循環して冷凍サイクルが実行される。すなわち冷媒は、高元側圧縮機１１１で超臨界の状態まで圧縮されて高温高圧となった後、高元側熱媒−冷媒熱交換器１１２において、負荷ユニット２００を循環する熱媒の高元側分流と熱交換する。次いで冷媒は、高元側膨張弁１１３で膨張後、カスケード熱交換器１０３において低元側ヒートポンプユニット１００の冷媒と熱交換し、高元側圧縮機１１１へ循環する。 The high-end heat pump unit 110 is configured by connecting a high-end compressor 111, a high-end heat medium-refrigerant heat exchanger 112, a high-end side expansion valve 113, and a cascade heat exchanger 103 through a refrigerant circulation path. This is a refrigeration circuit. As the refrigerant, CO ₂ is used as in the low side, and the refrigerant includes the high side compressor 111, the high side heat medium-refrigerant heat exchanger 112, the high side expansion valve 113, and the cascade heat exchanger 103. The refrigeration cycle is executed by circulating in this order. That is, the refrigerant is compressed to a supercritical state by the high-side compressor 111 and becomes a high temperature and high pressure, and then the high medium of the heat medium circulating in the load unit 200 in the high-side heat medium-refrigerant heat exchanger 112. Exchange heat with side branch. Next, the refrigerant is expanded by the high-side expansion valve 113, then exchanges heat with the refrigerant of the low-side heat pump unit 100 in the cascade heat exchanger 103, and circulates to the high-side compressor 111.

負荷ユニット２００は、上記同様、一例として床下に通したパイプに温水を流す床暖房ユニットである。第２実施形態の負荷ユニット２００は、熱媒として温水（水）を循環させる熱媒循環路２０１を備え、この熱媒循環路２０１において、暖房負荷より上流側に循環ポンプ２０２、下流側に膨張タンク２０３が設けられる。循環ポンプ２０２が往き熱媒を暖房負荷へ送り出して循環させ、膨張タンク２０３は、熱媒循環路２０１内の熱媒量を一定に保つために設けられる。 As described above, the load unit 200 is a floor heating unit that flows hot water through a pipe that passes under the floor as an example. The load unit 200 of the second embodiment includes a heat medium circulation path 201 that circulates hot water (water) as a heat medium. In the heat medium circulation path 201, the circulation pump 202 is upstream of the heating load, and the expansion is downstream. A tank 203 is provided. The circulation pump 202 sends out the forward heat medium to the heating load for circulation, and the expansion tank 203 is provided to keep the amount of the heat medium in the heat medium circulation path 201 constant.

熱媒循環路２０１は、暖房負荷より下流側で、２つの分流路、すなわち低元側流路２０１ａと高元側流路２０１ｂとに分岐しており、暖房負荷で使用されて戻ってくる戻り熱媒を、低元側熱媒−冷媒熱交換器１０２と高元側熱媒−冷媒熱交換器１１２とに分流させる。そして、第２実施形態の負荷ユニット２００では、分流して低元側流路２０１ａと高元側流路２０１ｂとに流れる熱媒分流量を調節する分流調節器として、分岐点に三方弁２０４が設けられている。この三方弁２０４により、目標とする往き熱媒の温度が得られるように、低元側熱媒−冷媒熱交換器１０２への熱媒分流量と高元側熱媒−冷媒熱交換器１１２への熱媒分流量とが調節される。三方弁２０４を用いることで、各流路２０１ａ，２０１ｂへの分流量調節が高精度に細かく行われる。三方弁２０４を使用する他に、高元側流路２０１ｂの途中に、分流して高元側流路２０１ｂへ流れる熱媒分流量を調節する流量制御弁を配設してもよい。あるいは、低元側熱媒−冷媒熱交換器１０２及び高元側熱媒−冷媒熱交換器１１２の下流側（出口側）で分流熱媒の分流量を調節する三方弁や流量制御弁を設ける例も可能である。 The heat medium circulation path 201 is branched downstream of the heating load into two branch paths, that is, a low-source-side flow path 201a and a high-source-side flow path 201b, and returned to be used by the heating load. The heat medium is divided into a low-source-side heat medium-refrigerant heat exchanger 102 and a high-source-side heat medium-refrigerant heat exchanger 112. In the load unit 200 according to the second embodiment, the three-way valve 204 is provided at the branch point as a flow dividing controller that adjusts the flow rate of the heat medium divided by flowing into the low flow channel 201a and the high flow channel 201b. Is provided. With this three-way valve 204, the flow rate of the heat medium to the low-source-side heat medium-refrigerant heat exchanger 102 and the high-source-side heat medium-refrigerant heat exchanger 112 so that the target temperature of the forward heat medium can be obtained. The heat transfer rate of the heat medium is adjusted. By using the three-way valve 204, minute flow rate adjustment to each of the flow paths 201a and 201b is finely performed with high accuracy. In addition to using the three-way valve 204, a flow rate control valve that adjusts the flow rate of the heat medium divided and flowing to the high-side channel 201b may be provided in the middle of the high-side channel 201b. Alternatively, a three-way valve or a flow control valve for adjusting the divided flow rate of the divided heat medium is provided on the downstream side (exit side) of the low-source side heat medium-refrigerant heat exchanger 102 and the high-source side heat medium-refrigerant heat exchanger 112. Examples are also possible.

第２実施形態の負荷ユニット２００は、低元側及び高元側流路２０１ａ，２０１ｂを通り、低元側熱媒−冷媒熱交換器１０２及び高元側熱媒−冷媒熱交換器１１２を通過した各分流熱媒を合流させて貯留する、所定容量の合流タンク２０５を備える。この合流タンク２０５に貯留される熱媒が、往き熱媒として熱媒循環路２０１を通り循環ポンプ２０２から暖房負荷へ送り出される。 The load unit 200 according to the second embodiment passes through the low-source side and high-side flow paths 201a and 201b and passes through the low-source side heat medium-refrigerant heat exchanger 102 and the high-source side heat medium-refrigerant heat exchanger 112. A merging tank 205 having a predetermined capacity is provided for merging and storing the divided heat transfer media. The heat medium stored in the merging tank 205 passes through the heat medium circulation path 201 as an outgoing heat medium and is sent from the circulation pump 202 to the heating load.

第１及び第２実施形態のタンク２４，２０５は、常時、熱媒で満たされるように構成される。すなわち、タンク２４，２０５は、熱媒を満水状態に貯留するものであり、タンク２４，２０５には、常に、１ＭＰａ程度の内圧がかかっている。また、タンク２４，２０５は、その上部に熱媒の流入口が設けられていると共に、その下部（底部）に熱媒の流出口が設けられている。このように、タンク２４，２０５を、常時、熱媒で満たすようにすることに加えて、熱媒の流出口をタンク２４，２０５の下部（底部）に設けることにより、タンク２４，２０５からは熱媒のみが流出されることとなり、回路内に空気が混入することが効果的に防止される。さらに、タンク２４，２０５には、逃し弁（図示省略）が設けられており、タンク内圧力が許容内圧を超えた場合には、前記逃し弁が開いて圧力を放出できるようになっている。 The tanks 24 and 205 of the first and second embodiments are configured to be always filled with a heat medium. That is, the tanks 24 and 205 store the heat medium in a full state, and an internal pressure of about 1 MPa is always applied to the tanks 24 and 205. The tanks 24 and 205 are provided with a heat medium inlet at the top and a heat medium outlet at the bottom (bottom). Thus, in addition to always filling the tanks 24 and 205 with the heat medium, by providing the heat medium outlet at the lower part (bottom part) of the tanks 24 and 205, the tanks 24 and 205 Only the heat medium flows out, and air is effectively prevented from entering the circuit. Furthermore, the tanks 24 and 205 are provided with relief valves (not shown) so that when the tank internal pressure exceeds the allowable internal pressure, the relief valves are opened to release the pressure.

負荷ユニット２００には、後述する各例のデフロスト運転用に、それぞれ点線で示す負荷迂回路２０６や熱交換器迂回路２０７を設けることが可能である。負荷迂回路２０６は、暖房負荷へ送り出される往き熱媒の通る熱媒循環路２０１中に挿入される三方弁２０６ａを有し、この三方弁２０６ａの開閉制御に従って、往き熱媒を暖房負荷へ送り出す通常の経路か、又は、暖房負荷からの戻り熱媒が通る熱媒循環路２０１へ往き熱媒を迂回させ、暖房負荷を通さずに低元側熱媒−冷媒熱交換器１０２へ戻す短絡経路が選択される。熱交換器迂回路２０７は、戻り熱媒分流後の低元側流路２０１ａ中に挿入される三方弁２０７ａを有し、この三方弁２０７ａの開閉制御に従って、分流路の熱媒を低元側熱媒−冷媒熱交換器１０２へ通す通常の経路か、又は、熱媒を低元側熱媒−冷媒熱交換器１０２を通さずに合流タンク２０５へ送る短絡経路が選択される。 The load unit 200 can be provided with a load bypass circuit 206 and a heat exchanger bypass circuit 207 indicated by dotted lines, respectively, for defrost operation of each example described later. The load bypass circuit 206 has a three-way valve 206a inserted into the heat medium circulation path 201 through which the forward heat medium sent to the heating load passes, and sends the forward heat medium to the heating load according to the opening / closing control of the three-way valve 206a. A normal path or a short-circuit path that bypasses the heating medium to the heating medium circulation path 201 through which the return heating medium from the heating load passes, and returns to the low-side heat medium-refrigerant heat exchanger 102 without passing through the heating load. Is selected. The heat exchanger bypass 207 has a three-way valve 207a inserted into the low-side flow path 201a after the return heat medium is divided, and the heat medium in the distribution path is transferred to the low-side side according to the opening / closing control of the three-way valve 207a. A normal path for passing through the heat medium-refrigerant heat exchanger 102 or a short-circuit path for sending the heat medium to the junction tank 205 without passing through the low-source side heat medium-refrigerant heat exchanger 102 is selected.

制御ユニット３００は、第１実施形態同様、ＥＣＵ（電子制御ユニット）等を備え、低元側及び高元側ヒートポンプユニット１００，１１０における圧縮機１０１，１１の各回転速度や膨張弁１０４，１１３の各開度、及び、負荷ユニット２００における循環ポンプ２０２の回転速度や三方弁２０４の開度等を制御する。制御にあたっては、外気温度センサＳａ、蒸発器温度センサＳｂ、熱交換前の低元側圧縮冷媒温度センサＳｃ、低元側熱交換後冷媒温度センサＳｄ、往き熱媒温度センサＳｅ、戻り熱媒温度センサＳｆ、熱交換後の低元側分流熱媒温度センサＳｇ、熱交換後の高元側分流熱媒温度センサＳｈ、熱交換前の高元側圧縮冷媒温度センサＳｉ、高元側熱交換後冷媒温度センサＳｊによる各測定値が使用される。この制御ユニット３００も、内蔵したプログラムに従ってデフロスト制御ユニットとして機能し、後述するデフロスト運転を制御する。 As in the first embodiment, the control unit 300 includes an ECU (electronic control unit) and the like, and includes the rotational speeds of the compressors 101 and 11 and the expansion valves 104 and 113 in the low-side and high-side heat pump units 100 and 110. Each opening degree, the rotational speed of the circulation pump 202 in the load unit 200, the opening degree of the three-way valve 204, and the like are controlled. In the control, the outside air temperature sensor Sa, the evaporator temperature sensor Sb, the low original side compressed refrigerant temperature sensor Sc before heat exchange, the low original side heat exchange refrigerant temperature sensor Sd, the forward heat medium temperature sensor Se, and the return heat medium temperature. Sensor Sf, low-source side divided heat medium temperature sensor Sg after heat exchange, high-source side divided heat medium temperature sensor Sh after heat exchange, high-source side compressed refrigerant temperature sensor Si before heat exchange, after high-source side heat exchange Each measured value by the refrigerant temperature sensor Sj is used. This control unit 300 also functions as a defrost control unit according to a built-in program, and controls a defrost operation to be described later.

第１及び第２実施形態の制御ユニット３０，３００は、通常の暖房運転で、操作パネルを通して設定される設定温度と、外気温度センサＳａにより測定される現在の外気温度とに基づいて、暖房能力（往き熱媒の温度目標値、圧縮機の回転速度）を決定する。そして、制御ユニット３０，３００は、往き熱媒温度センサＳｅにより測定される往き熱媒の測定温度が、決定した温度目標値となるように、ヒートポンプユニット１０，１００，１１０及び負荷ユニット２０，２００を制御する。制御ユニット３０，３００は、往き熱媒の測定温度が温度目標値に一致すると判断できたら、戻り熱媒温度センサＳｆにより測定される戻り熱媒の測定温度が、往き熱媒の温度目標値に対応した戻り熱媒の温度目標値になるか否か、判断する。制御ユニット３０，３００は、戻り熱媒の測定温度が戻り温度目標値になったと判断すれば、現在の暖房能力で制御を続行する。一方、戻り熱媒の測定温度が温度目標値にならない場合、制御ユニット３０，３００は、暖房能力を変更すべく再決定し、該再決定後の暖房能力で同制御を実行する。 The control units 30 and 300 according to the first and second embodiments perform heating capability based on the set temperature set through the operation panel and the current outside air temperature measured by the outside air temperature sensor Sa in normal heating operation. Determine the temperature target value of the forward heating medium and the rotational speed of the compressor. The control units 30 and 300 are configured so that the measured temperature of the forward heat medium measured by the forward heat medium temperature sensor Se becomes the determined temperature target value. To control. If the control units 30 and 300 can determine that the measured temperature of the forward heat medium matches the target temperature value, the measured temperature of the return heat medium measured by the return heat medium temperature sensor Sf becomes the target temperature value of the forward heat medium. It is determined whether or not the temperature target value of the corresponding return heat medium is reached. If the control units 30 and 300 determine that the measured temperature of the return heat medium has reached the return temperature target value, the control units 30 and 300 continue the control with the current heating capacity. On the other hand, when the measured temperature of the return heat medium does not reach the temperature target value, the control units 30 and 300 re-determine to change the heating capacity, and execute the same control with the heating capacity after the redetermination.

この暖房運転中にデフロスト制御ユニットとして機能する制御ユニット３０，３００は、第１例として、図３に示すフローチャートに沿ってデフロスト運転を制御する。 The control units 30 and 300 functioning as the defrost control unit during the heating operation control the defrost operation according to the flowchart shown in FIG. 3 as a first example.

デフロスト制御を実行する制御ユニット３０，３００は、ステップＳ０で、デフロスト開始条件の成立を判断する。例えば、デフロスト開始条件が成立したか否かは、外気温度センサＳａで測定される外気温度から算出される蒸発器温度の所定のしきい値と蒸発器温度センサＳｂで測定される蒸発器温度とを比較することで判断する。すなわち、蒸発器１４，１０５の温度は、霜が付くことによって、現在の外気温度よりも低温へ低下していくので、蒸発器温度が前記所定のしきい値になったときに、デフロスト開始条件が成立したと判断することができる。この他にも、蒸発器１４，１０５の入口／出口冷媒温度から判断することも可能である。 The control units 30 and 300 that execute the defrost control determine whether the defrost start condition is satisfied in step S0. For example, whether or not the defrost start condition is satisfied is determined by the predetermined threshold value of the evaporator temperature calculated from the outside air temperature measured by the outside air temperature sensor Sa and the evaporator temperature measured by the evaporator temperature sensor Sb. Judge by comparing. That is, since the temperatures of the evaporators 14 and 105 are lowered to the lower temperature than the current outside air temperature due to frost, the defrost start condition is reached when the evaporator temperature reaches the predetermined threshold value. It can be determined that In addition to this, it is also possible to judge from the inlet / outlet refrigerant temperature of the evaporators 14 and 105.

デフロスト開始条件が成立したと判断した制御ユニット３０，３００は、ステップＳ１で、膨張弁１３，１０４を全開にし、且つ例えばファンを停止するなどで蒸発器１４，１０５の蒸発動作を止め、さらに、循環ポンプ２２，２０２を停止するなどで負荷ユニット２０，２００における熱媒循環を止めた状態とする。また、第２実施形態のヒートポンプ装置の場合は、高元側ヒートポンプユニット１１０の圧縮機１１１を停止するなどで高元側の冷媒循環も止めた状態とする。そして、ヒートポンプユニット１０，１００の冷媒を熱交換なしで循環させるデフロスト運転を実行する。これにより、冷媒がホットガスとして蒸発器１４，１０５へ提供され、その熱で除霜が行われる。このように、本実施形態のヒートポンプ装置は、ヒートポンプユニットの冷凍サイクルを逆回転させず、通常の順方向のサイクルで冷媒を循環させてデフロスト運転を実行する。したがって、逆回転用の余分な部品が不要であり、回路の負担が少ない。 The control units 30 and 300 that have determined that the defrost start condition has been satisfied stop the evaporation operation of the evaporators 14 and 105 by opening the expansion valves 13 and 104 and stopping the fan, for example, in step S1, The circulation of the heat medium in the load units 20 and 200 is stopped by stopping the circulation pumps 22 and 202, for example. Moreover, in the case of the heat pump apparatus of 2nd Embodiment, it is set as the state which also stopped the refrigerant | coolant circulation of the high side by stopping the compressor 111 of the high side heat pump unit 110, etc. And the defrost operation which circulates the refrigerant | coolant of the heat pump units 10 and 100 without heat exchange is performed. Thereby, a refrigerant | coolant is provided to the evaporators 14 and 105 as hot gas, and the defrost is performed with the heat. As described above, the heat pump device of the present embodiment performs the defrost operation by circulating the refrigerant in the normal forward cycle without rotating the refrigeration cycle of the heat pump unit in the reverse direction. Therefore, no extra parts for reverse rotation are required, and the circuit load is small.

デフロスト運転中の制御ユニット３０，３００は、ステップＳ２で、冷媒温度センサＳｄで測定される冷媒温度を、戻り熱媒温度センサＳｆで測定される熱媒温度と比較する。比較の結果、両者が熱媒温度＜冷媒温度の温度関係にある場合、制御ユニット３０，３００は、ステップＳ３へ進んでデフロスト終了条件の成立を判断する。一方、両者が熱媒温度≧冷媒温度の温度関係になると、制御ユニット３０，３００は、ステップＳ４へ進んで、熱媒−冷媒熱交換器１２，１０２で冷媒と熱媒が熱交換するように、熱媒循環制御を実行した後に、ステップＳ３へ進んでデフロスト終了条件の成立を判断する。すなわち、ホットガスとして使用されて温度が低下していく冷媒の温度が、熱媒の温度以下になる場合には、熱媒の熱を冷媒へ回収するように制御し、冷媒の温度低下を抑制する。これにより、デフロスト運転の後半で冷媒の温度を上げるように制御できるので、デフロスト運転の時間を従来に比べて短縮することができる。 In step S2, the control units 30 and 300 during the defrosting operation compare the refrigerant temperature measured by the refrigerant temperature sensor Sd with the heat medium temperature measured by the return heat medium temperature sensor Sf. As a result of the comparison, when both are in the temperature relationship of heat medium temperature <refrigerant temperature, the control units 30 and 300 proceed to step S3 and determine whether the defrost end condition is satisfied. On the other hand, when the temperature relationship of both is such that the heat medium temperature ≧ refrigerant temperature, the control units 30 and 300 proceed to step S4 so that the refrigerant and the heat medium exchange heat with the heat medium-refrigerant heat exchangers 12, 102. Then, after the heat medium circulation control is executed, the process proceeds to step S3 to determine whether the defrost end condition is satisfied. In other words, when the temperature of the refrigerant that is used as hot gas and the temperature decreases is below the temperature of the heat medium, control is performed to recover the heat of the heat medium to the refrigerant, thereby suppressing the temperature decrease of the refrigerant. To do. Thereby, since it can control to raise the temperature of a refrigerant | coolant in the second half of defrost operation, the time of defrost operation can be shortened compared with the past.

ステップＳ４で熱媒循環制御を行う第１実施形態の制御ユニット３０は、循環ポンプ２２を所定の回転速度で制御して、タンク２４の熱媒を負荷ユニット２０内で循環させる。この制御の場合、デフロスト運転終了前に熱媒が暖房負荷を通って循環し始めるので、あたかもデフロスト運転が早く終了したかのような印象を与えられる利点がある。図１中に示すように負荷迂回路２５が設けられている場合の制御ユニット３０は、循環ポンプ２２を制御すると共に負荷迂回路２５を開通させ、暖房負荷を通さずに熱媒を循環させる。この制御の場合、暖房負荷で熱媒の熱が奪われないので、より長く熱媒の温度を保つことができる。このように負荷ユニット２０において熱媒が循環することにより、熱媒−冷媒熱交換器１２で熱媒と冷媒が熱交換し、冷媒の温度を上げることができる。 The control unit 30 of the first embodiment that performs the heat medium circulation control in step S4 controls the circulation pump 22 at a predetermined rotational speed to circulate the heat medium in the tank 24 in the load unit 20. In the case of this control, since the heat medium starts to circulate through the heating load before the defrost operation is completed, there is an advantage that an impression can be given as if the defrost operation was completed early. As shown in FIG. 1, the control unit 30 provided with the load bypass circuit 25 controls the circulation pump 22 and opens the load bypass circuit 25 to circulate the heat medium without passing through the heating load. In the case of this control, since the heat of the heat medium is not deprived by the heating load, the temperature of the heat medium can be maintained for a longer time. Thus, when the heat medium circulates in the load unit 20, the heat medium and the refrigerant exchange heat in the heat medium-refrigerant heat exchanger 12, and the temperature of the refrigerant can be raised.

他方、ステップＳ４で熱媒循環制御を行う第２実施形態の制御ユニット３００は、分流調節器である三方弁２０４を低元側流路２０１ａの１００％流通へ切り換えると共に循環ポンプ２０２を所定の回転速度で制御して、合流タンク２０５の熱媒を負荷ユニット２００内で低元側のみ循環させる。また、図２中に示すように負荷迂回路２０６が設けられている場合の制御ユニット３００は、三方弁２０４及び循環ポンプ２０２を制御すると共に負荷迂回路２０６を開通させ、暖房負荷を通さずに熱媒を低元側で循環させる。これら制御で第１実施形態同様の上記作用を得られる。 On the other hand, the control unit 300 of the second embodiment that performs heat medium circulation control in step S4 switches the three-way valve 204, which is a flow dividing regulator, to 100% circulation of the low-side flow path 201a and rotates the circulation pump 202 by a predetermined rotation. Controlled by the speed, the heat medium in the merging tank 205 is circulated in the load unit 200 only on the low-source side. Further, as shown in FIG. 2, the control unit 300 in the case where the load bypass circuit 206 is provided controls the three-way valve 204 and the circulation pump 202 and opens the load bypass circuit 206 without passing the heating load. Circulate the heat medium on the low side. With these controls, the same action as in the first embodiment can be obtained.

ステップＳ３へ進んだ制御ユニット３０，３００は、蒸発器温度センサＳｂで測定される蒸発器温度が終了判断温度（例えば５℃）を上回るか否かでデフロスト終了条件の成立を判断する。制御ユニット３０，３００は、デフロスト終了条件が成立しない間はステップＳ２以降の制御を継続し、デフロスト終了条件が成立すれば、ステップＳ５でデフロスト運転を終了して通常の暖房運転を開始し、ステップＳ０へ戻ってデフロスト開始条件の成立を判断する。デフロスト終了条件は、蒸発器温度の他にも、蒸発器出口冷媒温度など、冷媒温度で判断することも可能である。 The control units 30 and 300 that have proceeded to step S3 determine whether or not the defrost end condition is satisfied depending on whether or not the evaporator temperature measured by the evaporator temperature sensor Sb exceeds the end determination temperature (for example, 5 ° C.). The control units 30 and 300 continue the control after step S2 while the defrost end condition is not satisfied. If the defrost end condition is satisfied, the control unit 30 and 300 ends the defrost operation and starts the normal heating operation at step S5. Returning to S0, it is determined whether the defrost start condition is satisfied. The defrost end condition can be determined by the refrigerant temperature such as the evaporator outlet refrigerant temperature in addition to the evaporator temperature.

図４には、デフロスト制御ユニットとして機能する制御ユニット３０，３００が実行するデフロスト制御の第２例に係るフローチャートを示す。この第２例は、図１及び図２中に示す熱交換器迂回経路２６，２０７が設けられている場合の制御例である。 FIG. 4 shows a flowchart according to a second example of the defrost control executed by the control units 30 and 300 functioning as the defrost control unit. This second example is a control example in the case where the heat exchanger detour paths 26 and 207 shown in FIGS. 1 and 2 are provided.

デフロスト制御を実行する制御ユニット３０，３００は、第１例同様にステップＳ１０で、デフロスト開始条件の成立を判断する。デフロスト開始条件が成立したと判断した制御ユニット３０，３００は、ステップＳ１１で、第１例同様に膨張弁１３，１０４を全開にし且つ蒸発器１４，１０５の蒸発動作を止めた状態とする。また、第２実施形態のヒートポンプ装置の場合は、高元側ヒートポンプユニット１１０の圧縮機１１１を停止するなどで高元側の冷媒循環を止めた状態とする。このときに三方弁２０４は、低元側流路２０１ａへの１００％流通に切り換えるのが好ましい。さらに、第２例の場合、制御ユニット３０，３００は、熱交換器迂回路２６，２０７を開通させ、熱媒−冷媒熱交換器１２，１０２を迂回して熱媒を合流タンク２０５へ循環させる。これにより、第１例同様、ヒートポンプユニット１０，１００の冷媒を熱交換なしでホットガスとして循環させるデフロスト運転が実行される。 The control units 30 and 300 that execute the defrost control determine whether or not the defrost start condition is satisfied in step S10 as in the first example. The control units 30 and 300 that have determined that the defrost start condition has been satisfied are in a state where the expansion valves 13 and 104 are fully opened and the evaporation operations of the evaporators 14 and 105 are stopped in step S11 as in the first example. Moreover, in the case of the heat pump apparatus of 2nd Embodiment, it is set as the state which stopped the refrigerant | coolant circulation of the high side by stopping the compressor 111 of the high side heat pump unit 110. At this time, the three-way valve 204 is preferably switched to 100% flow to the low-source side flow path 201a. Further, in the case of the second example, the control units 30 and 300 open the heat exchanger bypass circuits 26 and 207, bypass the heat medium-refrigerant heat exchangers 12 and 102, and circulate the heat medium to the junction tank 205. . Thereby, the defrost operation which circulates the refrigerant | coolant of the heat pump units 10 and 100 as hot gas without heat exchange is performed like a 1st example.

第２例の場合、制御ユニット３０，３００は、デフロスト運転中、循環ポンプ２２，２０２を所定の回転速度に制御して負荷ユニット２０，２００における熱媒の循環を維持するように制御することができる。すなわち、デフロスト運転中もある程度の熱媒を循環させ、暖房の途切れを意識させない運転とすることが可能である。 In the case of the second example, the control units 30 and 300 can control the circulation pumps 22 and 202 to a predetermined rotational speed during the defrost operation so as to maintain the circulation of the heat medium in the load units 20 and 200. it can. That is, it is possible to circulate a certain amount of heat medium even during the defrosting operation so that the operation is not made aware of the interruption of heating.

デフロスト運転中の制御ユニット３０，３００は、第１例同様にステップＳ１２で、冷媒温度センサＳｄで測定される冷媒温度を、戻り熱媒温度センサＳｆで測定される熱媒温度と比較する。比較の結果、制御ユニット３０，３００は、熱媒温度＜冷媒温度の温度関係にあればステップＳ１３へ進んでデフロスト終了条件の成立を判断し、熱媒温度≧冷媒温度の温度関係になれば、ステップＳ１４へ進んで、熱媒−冷媒熱交換器１２，１０２で冷媒と熱媒が熱交換するように、熱交換器迂回路２６，２０７を閉鎖する。熱交換器迂回路２６，２０７の閉鎖により、循環ポンプ２２，２０２によって循環する熱媒が熱媒−冷媒熱交換器１２，１０２を通るので、当該熱媒の熱が冷媒へ回収され、第１例同様の作用を得られる。 The control units 30 and 300 during the defrost operation compare the refrigerant temperature measured by the refrigerant temperature sensor Sd with the heating medium temperature measured by the return heating medium temperature sensor Sf in step S12 as in the first example. As a result of the comparison, if the temperature relationship of the heat medium temperature <refrigerant temperature is satisfied, the control units 30 and 300 proceed to step S13 to determine that the defrost end condition is satisfied, and if the temperature relationship of heat medium temperature ≧ refrigerant temperature is satisfied, Proceeding to step S14, the heat exchanger detours 26 and 207 are closed so that the heat exchange between the refrigerant and the heat medium is performed in the heat medium-refrigerant heat exchangers 12 and 102. When the heat exchanger detours 26 and 207 are closed, the heat medium circulated by the circulation pumps 22 and 202 passes through the heat medium-refrigerant heat exchangers 12 and 102, so that the heat of the heat medium is recovered into the refrigerant, and the first The same effect as the example can be obtained.

ステップＳ１２又はステップＳ１４の後にステップＳ１３へ進んだ制御ユニット３０，３００は、第１例同様に、蒸発器温度センサＳｂで測定される蒸発器温度が終了判断温度を上回るか否かでデフロスト終了条件の成立を判断する。制御ユニット３０，３００は、デフロスト終了条件が成立しない間はステップＳ１２以降の制御を継続し、デフロスト終了条件が成立すれば、ステップＳ１５でデフロスト運転を終了して通常の暖房運転を開始し、ステップＳ１０へ戻ってデフロスト開始条件の成立を判断する。 The control units 30 and 300 that proceed to step S13 after step S12 or step S14 determine whether or not the defrost end condition depends on whether the evaporator temperature measured by the evaporator temperature sensor Sb exceeds the end determination temperature, as in the first example. Is determined. The control units 30 and 300 continue the control after step S12 while the defrost end condition is not satisfied. If the defrost end condition is satisfied, the control unit 30 and 300 ends the defrost operation and starts the normal heating operation at step S15. Returning to S10, it is determined whether the defrost start condition is satisfied.

１０ヒートポンプユニット
１１圧縮機
１２熱媒−冷媒熱交換器
１３膨張弁
１４蒸発器
２０負荷ユニット
２１熱媒循環路
２２循環ポンプ
２３膨張タンク
２４タンク
２５負荷迂回路
２５ａ三方弁
２６熱交換器迂回路
２６ａ三方弁
３０制御ユニット（デフロスト制御ユニット）
１００低元側ヒートポンプユニット
１０１低元側圧縮機
１０２低元側熱媒−冷媒熱交換器
１０３カスケード熱交換器
１０４低元側膨張弁
１０５低元側蒸発器
１１０高元側ヒートポンプユニット
１１１高元側圧縮機
１１２高元側熱媒−冷媒熱交換器
１１３高元側膨張弁
２００負荷ユニット
２０１熱媒循環路
２０１ａ低元側流路
２０１ｂ高元側流路
２０２循環ポンプ
２０３膨張タンク
２０４三方弁（分流調節器）
２０５合流タンク
２０６負荷迂回路
２０６ａ三方弁
２０７熱交換器迂回路
２０７ａ三方弁
３００制御ユニット
Ｓａ〜Ｓｊ温度センサ DESCRIPTION OF SYMBOLS 10 Heat pump unit 11 Compressor 12 Heat medium-refrigerant heat exchanger 13 Expansion valve 14 Evaporator 20 Load unit 21 Heat medium circulation path 22 Circulation pump 23 Expansion tank 24 Tank 25 Load bypass circuit 25a Three-way valve 26 Heat exchanger bypass circuit 26a Three-way valve 30 control unit (defrost control unit)
100 Low-source-side heat pump unit 101 Low-source-side compressor 102 Low-source-side heat medium-refrigerant heat exchanger 103 Cascade heat exchanger 104 Low-source-side expansion valve 105 Low-source-side evaporator 110 High-source-side heat pump unit 111 High-source-side Compressor 112 High-end heat medium-refrigerant heat exchanger 113 High-end expansion valve 200 Load unit 201 Heat-medium circulation path 201a Low-end side flow path 201b High-end side flow path 202 Circulation pump 203 Expansion tank 204 Three-way valve (Branch) Regulator)
205 Junction tank 206 Load bypass circuit 206a Three-way valve 207 Heat exchanger bypass circuit 207a Three-way valve 300 Control units Sa to Sj Temperature sensor

Claims

A heat pump unit in which refrigerant circulates in the order of a compressor, a heat medium-refrigerant heat exchanger, an expansion valve, and an evaporator;
A tank for storing the heat medium exchanged with the heat medium-refrigerant heat exchanger;
A circulation pump for passing the heating medium of the tank to a load and circulating it to the heating medium-refrigerant heat exchanger;
When the defrost start condition is met, when the defrost start condition is met, the refrigerant is circulated in a state where the expansion valve is fully opened and the evaporation operation of the evaporator is stopped and the heat medium circulation by the circulation pump is stopped. A defrost control unit for performing defrost operation,
Comprising
The defrost control unit is
When the refrigerant and the heat medium are in a predetermined temperature relationship during the defrost operation, the circulation pump is controlled so that the refrigerant and the heat medium exchange heat with the heat medium-refrigerant heat exchanger.
Heat pump device.

In order to return the heat medium to the heat medium-refrigerant heat exchanger without passing through the load, it further includes a load bypass that can be opened and closed,
The defrost control unit is
When the refrigerant and the heat medium are in a predetermined temperature relationship during the defrost operation, the circulation pump is controlled and the load is controlled so that the refrigerant and the heat medium exchange heat with the heat medium-refrigerant heat exchanger. Open a detour,
The heat pump apparatus according to claim 1.

A heat pump unit in which refrigerant circulates in the order of a compressor, a heat medium-refrigerant heat exchanger, an expansion valve, and an evaporator;
A tank for storing the heat medium exchanged with the heat medium-refrigerant heat exchanger;
A circulation pump for passing the heating medium of the tank to a load and circulating it to the heating medium-refrigerant heat exchanger;
A heat exchanger detour that can be opened and closed to send the heating medium returning from the load to the tank without passing through the heating medium-refrigerant heat exchanger;
When the defrost start condition is satisfied, the refrigerant is circulated in a state where the expansion valve is fully opened, the evaporation operation of the evaporator is stopped and the heat exchanger bypass is opened when the defrost start condition is satisfied. A defrost control unit for performing defrost operation,
Comprising
The defrost control unit is
When the refrigerant and the heat medium have a predetermined temperature relationship during the defrost operation, the heat exchanger detour is closed so that the refrigerant and the heat medium exchange heat with the heat medium-refrigerant heat exchanger. ,
Heat pump device.

A low source side heat pump unit in which the refrigerant circulates in the order of a low source side compressor, a low source side heat medium-refrigerant heat exchanger, a cascade heat exchanger, a low source side expansion valve, and a low source side evaporator;
A high-source side heat pump unit in which refrigerant is circulated in the order of a high-source side compressor, a high-source side heat medium-refrigerant heat exchanger, a high-source side expansion valve, and the cascade heat exchanger;
A circulation pump that circulates the heat medium through the load, and divides the return heat medium from the load into the low-source side heat medium-refrigerant heat exchanger and the high-source side heat medium-refrigerant heat exchanger; , The low-temperature side heat medium-refrigerant heat exchanger and the respective high-temperature side heat medium-refrigerant heat exchangers are combined and stored in a merging tank, and the heat medium in the merging tank is loaded with the load. The flow control is configured to adjust the flow rate of the heat medium to the low heat medium-refrigerant heat exchanger and the flow rate of heat medium to the high heat medium-refrigerant heat exchanger. A load unit equipped with a container,
When the defrost start condition is satisfied, and when the defrost start condition is satisfied, the low-side expansion valve is fully opened and the evaporation operation of the low-side evaporator is stopped and the heat medium circulation by the circulation pump is stopped. A defrost control unit for performing a defrost operation for circulating the refrigerant of the low-source side heat pump unit in a state;
Comprising
The defrost control unit is
When the refrigerant and the heat medium are in a predetermined temperature relationship during the defrost operation, the flow regulator and the heat medium are exchanged so that the refrigerant and the heat medium exchange heat with the low-side heat medium-refrigerant heat exchanger. Control the circulation pump,
Heat pump device.

In order to return the heat medium to the low-source heat medium-refrigerant heat exchanger without passing through the load, the heat medium further includes a load bypass that can be opened and closed,
The defrost control unit is
When the refrigerant and the heat medium are in a predetermined temperature relationship during the defrost operation, the flow regulator and the heat medium are exchanged so that the refrigerant and the heat medium exchange heat with the low-side heat medium-refrigerant heat exchanger. Controlling the circulation pump and opening the load bypass circuit;
The heat pump apparatus according to claim 4.

A low source side heat pump unit in which the refrigerant circulates in the order of a low source side compressor, a low source side heat medium-refrigerant heat exchanger, a cascade heat exchanger, a low source side expansion valve, and a low source side evaporator;
A high-source side heat pump unit in which refrigerant is circulated in the order of a high-source side compressor, a high-source side heat medium-refrigerant heat exchanger, a high-source side expansion valve, and the cascade heat exchanger;
A circulation pump that circulates the heat medium through the load, and divides the return heat medium from the load into the low-source side heat medium-refrigerant heat exchanger and the high-source side heat medium-refrigerant heat exchanger; , The low-temperature side heat medium-refrigerant heat exchanger and the respective high-temperature side heat medium-refrigerant heat exchangers are combined and stored in a merging tank, and the heat medium in the merging tank is loaded with the load. The flow control is configured to adjust the flow rate of the heat medium to the low heat medium-refrigerant heat exchanger and the flow rate of heat medium to the high heat medium-refrigerant heat exchanger. A load unit equipped with a container,
A heat exchanger detour that can be opened and closed to send the heat medium flowing to the low-source-side heat medium-refrigerant heat exchanger to the junction tank without passing through the low-source-side heat medium-refrigerant heat exchanger;
When the defrost start condition is met, when the defrost start condition is met, the low-side expansion valve is fully opened and the evaporation operation of the low-side evaporator is stopped and the heat exchanger bypass is opened. A defrost control unit for performing a defrost operation for circulating the refrigerant of the low-source side heat pump unit in a state;
Comprising
The defrost control unit is
When the refrigerant and the heat medium of the low-side heat pump unit are in a predetermined temperature relationship during the defrost operation, the refrigerant and the heat medium exchange heat with the low-side heat medium-refrigerant heat exchanger. Closing the heat exchanger bypass,
Heat pump device.