JP6766595B2

JP6766595B2 - Air conditioner

Info

Publication number: JP6766595B2
Application number: JP2016212732A
Authority: JP
Inventors: 博俊竹内; 慎太郎真田; 賢一 ▲高▼野; 亮 ▲高▼岡
Original assignee: Fujitsu General Ltd
Current assignee: Fujitsu General Ltd
Priority date: 2016-10-31
Filing date: 2016-10-31
Publication date: 2020-10-14
Anticipated expiration: 2036-10-31
Also published as: JP2018071893A

Description

本発明は、少なくとも１台の室外機に複数台の室内機が冷媒配管で接続されたマルチ型空気調和装置に係わり、より詳細には、停止中の室内機から発生する冷媒音を低減しつつ、除霜運転中の冷媒循環量不足を抑制できる空気調和装置に関する。 The present invention relates to a multi-type air conditioner in which a plurality of indoor units are connected to at least one outdoor unit by a refrigerant pipe, and more specifically, while reducing the refrigerant noise generated from the stopped indoor unit. The present invention relates to an air conditioner capable of suppressing a shortage of refrigerant circulation during defrosting operation.

１台の室外機に複数台の室内機が並列に接続されるマルチ型空気調和装置において、暖房運転中に室外熱交換器に霜が付着した場合に、冷媒回路を冷房サイクルで運転させて除霜を行うリバース除霜運転が行われている。除霜運転は、室外熱交換器の温度が所定温度以上に上昇したとき、又は、除霜運転開始から予め定められた所定時間を経過したときに終了し、冷媒回路を暖房サイクルで運転させて暖房運転に復帰する。
従来、暖房運転中に複数台の室内機のうちいずれかを運転停止させる場合、当該室内機に対応する膨張弁は全閉若しくは微小開度となっていた。また、その後除霜運転が行われても当該室内機に対応する膨張弁は全閉若しくは微小開度の状態を維持していた。
そのため、運転停止中の室内機の台数が多いと、除霜運転時に室内機の室内熱交換器で吸熱される熱が少なくなり、除霜に費やす時間が長くなってしまうだけでなく、冷媒回路内の低圧が大きく低下し、この結果、低圧保護動作によって空気調和装置が異常停止してしまうという不具合があった。 In a multi-type air conditioner in which multiple indoor units are connected in parallel to one outdoor unit, if frost adheres to the outdoor heat exchanger during heating operation, the refrigerant circuit is operated in a cooling cycle to remove it. A reverse defrosting operation that frosts is performed. The defrosting operation ends when the temperature of the outdoor heat exchanger rises above a predetermined temperature, or when a predetermined predetermined time has elapsed from the start of the defrosting operation, and the refrigerant circuit is operated in a heating cycle. Return to heating operation.
Conventionally, when any one of a plurality of indoor units is stopped during the heating operation, the expansion valve corresponding to the indoor unit is fully closed or has a minute opening. Further, even if the defrosting operation was subsequently performed, the expansion valve corresponding to the indoor unit was maintained in a fully closed state or a state of a minute opening.
Therefore, if the number of indoor units that are stopped is large, the heat absorbed by the indoor heat exchanger of the indoor unit during defrosting operation is reduced, which not only increases the time spent for defrosting, but also the refrigerant circuit. There was a problem that the low pressure inside was greatly reduced, and as a result, the air conditioner stopped abnormally due to the low pressure protection operation.

これを回避するために、除霜運転時、運転停止中の室内機に対応する膨張弁を全開に制御する方法がある（例えば、特許文献１）。この方法であれば、運転停止中の室内機の台数が多い場合であっても除霜運転時に室内機の室内熱交換器で吸熱される熱を十分に確保できる。 In order to avoid this, there is a method of controlling the expansion valve corresponding to the indoor unit that is stopped during the defrosting operation to the full open (for example, Patent Document 1). With this method, even when the number of indoor units stopped is large, it is possible to sufficiently secure the heat absorbed by the indoor heat exchanger of the indoor unit during the defrosting operation.

しかし、運転停止中の室内機に対応する膨張弁の開度を全開にすると、当該運転停止中の室内機の室内熱交換器内を流れる冷媒の量が増加する。当該運転停止中の室内機の室内熱交換器内を流れる冷媒の量が増加すると、当該運転停止中の室内機から発生する冷媒音が増大し、ユーザに不快感を与えてしまう。
また、除霜運転時、運転停止中の室内機に対応する膨張弁が冷媒音を考慮して予め定めた固定の開度となるように制御する方法も考えられるが、除霜運転時に必要な室内機一台当たりの室内熱交換器での吸熱量は、室内機の接続台数や運転台数によって異なるため、このような方法では着霜量に応じた膨張弁の開度制御に改良の余地がある。 However, when the opening degree of the expansion valve corresponding to the indoor unit whose operation is stopped is fully opened, the amount of the refrigerant flowing in the indoor heat exchanger of the indoor unit whose operation is stopped increases. When the amount of the refrigerant flowing in the indoor heat exchanger of the indoor unit during the operation stop increases, the refrigerant noise generated from the indoor unit during the operation stop increases, which causes discomfort to the user.
It is also conceivable to control the expansion valve corresponding to the indoor unit that is stopped during the defrosting operation so that it has a predetermined fixed opening in consideration of the refrigerant noise, but it is necessary during the defrosting operation. Since the amount of heat absorbed by the indoor heat exchanger per indoor unit differs depending on the number of connected indoor units and the number of operating units, there is room for improvement in the opening control of the expansion valve according to the amount of frost formation by such a method. is there.

特開平５−２０３２９６号公報Japanese Patent Application Laid-Open No. 5-203296

本発明は以上述べた問題点を解決するものであって、運転停止中の室内機の台数が多い場合であっても、除霜運転時に室内機の室内熱交換器で吸熱される熱を十分に確保しつつ、運転停止中の室内機から発生する冷媒音を低減する空気調和装置を提供することを目的とする。 The present invention solves the above-mentioned problems, and even when the number of indoor units stopped is large, the heat absorbed by the indoor heat exchanger of the indoor unit during the defrosting operation is sufficiently sufficient. It is an object of the present invention to provide an air conditioner that reduces the refrigerant noise generated from an indoor unit that is stopped while ensuring the above.

上記の課題を解決するために、本発明の空気調和装置は、圧縮機と、室外熱交換器と、前記室外熱交換器を流通する冷媒の温度である室外熱交温度を検出する室外熱交温度検出手段と、外気温度を検出する外気温度検出手段とを有する室外機と、室内熱交換器を有する室内機と、を有し、１台の前記室外機に対して複数の室内機が冷媒配管で並列に接続された空気調和装置であって、前記室内機の各々に対応して接続された膨張弁と、暖房運転時に、前記圧縮機、前記室内熱交換器、前記膨張弁、前記室外熱交換器の順で冷媒が循環する冷媒回路と、前記冷媒回路に備えられ、除霜運転中に、圧縮機から吐出された冷媒を前記室外熱交換器に向かうように冷媒の流れを切り替える流路切替手段と、前記圧縮機と、前記膨張弁と、前記流路切替手段とを制御する制御手段と、を備え、前記制御手段は、暖房運転を行っているときに前記室外熱交換器で霜が発生しているか否かを判定する着霜判定を行い、前記着霜判定において、前記室外熱交換器で霜が発生していると判定した場合、前記室外熱交温度と前記外気温度と前記圧縮機の回転数から着霜量を推定し、当該着霜量に基づいて、前記着霜判定時に運転停止していた前記室内機に対応する前記膨張弁の適正開度を決定したのち前記除霜運転を実行し、前記除霜運転中において、前記着霜判定時に運転停止していた前記室内機に対応する前記膨張弁の開度を前記適正開度となるように制御する。 In order to solve the above problems, the air conditioner of the present invention detects the outdoor heat exchange temperature, which is the temperature of the compressor, the outdoor heat exchanger, and the refrigerant flowing through the outdoor heat exchanger. It has an outdoor unit having a temperature detecting means, an outside air temperature detecting means for detecting the outside air temperature, and an indoor unit having an indoor heat exchanger, and a plurality of indoor units are used as a refrigerant for one outdoor unit. An air conditioner connected in parallel by piping, and an expansion valve connected to each of the indoor units, and the compressor, the indoor heat exchanger, the expansion valve, and the outdoor during heating operation. A refrigerant circuit in which the refrigerant circulates in the order of the heat exchanger, and a flow provided in the refrigerant circuit that switches the flow of the refrigerant so that the refrigerant discharged from the compressor is directed to the outdoor heat exchanger during the defrosting operation. A path switching means, a compressor, an expansion valve, and a control means for controlling the flow path switching means are provided, and the control means is used by the outdoor heat exchanger during a heating operation. A frost formation determination is performed to determine whether or not frost is generated, and when it is determined in the frost formation determination that frost is being generated in the outdoor heat exchanger, the outdoor heat exchange temperature and the outside air temperature are determined. The amount of frost formation is estimated from the rotation speed of the compressor, and based on the amount of frost formation, the appropriate opening degree of the expansion valve corresponding to the indoor unit that was stopped at the time of the frost formation determination is determined. The defrosting operation is executed, and during the defrosting operation, the opening degree of the expansion valve corresponding to the indoor unit that was stopped at the time of the frost formation determination is controlled to be the appropriate opening degree.

また、好ましくは、前記圧縮機の回転数に基づいて、前記着霜量を変更する。 Further, preferably, the amount of frost formation is changed based on the rotation speed of the compressor.

上記のように構成した本発明の空気調和装置によれば、運転停止中の室内機の台数が多い場合であっても、除霜運転時に室内機の室内熱交換器で吸熱される熱を十分に確保しつつ、運転停止中の室内機から発生する冷媒音を低減できる。 According to the air conditioner of the present invention configured as described above, even when the number of indoor units stopped is large, the heat absorbed by the indoor heat exchanger of the indoor unit during the defrosting operation is sufficient. It is possible to reduce the refrigerant noise generated from the indoor unit when the operation is stopped, while ensuring the above.

本発明の実施形態である空気調和装置の説明図であり、（Ａ）が冷媒回路図、（Ｂ）が室外機制御手段および室内機制御手段のブロック図である。It is explanatory drawing of the air conditioner which is embodiment of this invention, (A) is a refrigerant circuit diagram, (B) is a block diagram of an outdoor unit control means and an indoor unit control means. 本発明の実施形態における、室外機制御手段での処理を説明するフローチャートである。It is a flowchart explaining the process by the outdoor unit control means in embodiment of this invention. 本発明の実施形態における、室外機制御手段での処理を説明するテーブルである。It is a table explaining the process by the outdoor unit control means in embodiment of this invention. 本発明の実施形態における、室外機制御手段での処理を説明するテーブルである。It is a table explaining the process by the outdoor unit control means in embodiment of this invention.

以下、本発明の実施の形態を、添付図面に基づいて詳細に説明する。実施形態としては、１台の室外機に４台の室内機が並列に接続され、全ての室内機で同時に冷房運転あるいは暖房運転が行えるマルチ型の空気調和装置を例に挙げて説明する。尚、本発明は以下の実施形態に限定されることはなく、本発明の主旨を逸脱しない範囲で種々変形することが可能である。 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. As an embodiment, a multi-type air conditioner in which four indoor units are connected in parallel to one outdoor unit and all the indoor units can be simultaneously cooled or heated will be described as an example. The present invention is not limited to the following embodiments, and various modifications can be made without departing from the gist of the present invention.

図１（Ａ）に示すように、本実施形態における空気調和装置１は、１台の室外機２と、室外機２に第１液管８ａ、第２液管８ｂ、第３液管８ｃ、第４液管８ｄ、および、ガス管９で並列に接続された４台の室内機５ａ〜５ｄとを備えている。 As shown in FIG. 1A, the air conditioner 1 in the present embodiment includes one outdoor unit 2 and the outdoor unit 2 with a first liquid pipe 8a, a second liquid pipe 8b, and a third liquid pipe 8c. It includes a fourth liquid pipe 8d and four indoor units 5a to 5d connected in parallel by a gas pipe 9.

上記各構成要素は次のように接続されている。第１液管８ａの一端が室外機２の第１液側閉鎖弁２８ａに、他端が室内機５ａの液側閉鎖弁５３ａにそれぞれ接続されている。また、第２液管８ｂの一端が室外機２の第２液側閉鎖弁２８ｂに、他端が室内機５ｂの液側閉鎖弁５３ｂにそれぞれ接続されている。また、第３液管８ｃの一端が室外機２の第３液側閉鎖弁２８ｃに、他端が室内機５ｃの液側閉鎖弁５３ｃにそれぞれ接続されている。また、第４液管８ｄの一端が室外機２の第４液側閉鎖弁２８ｄに、他端が室内機５ｄの液側閉鎖弁５３ｄにそれぞれ接続されている。また、ガス管９は一端が室外機２のガス側閉鎖弁２９に、他端が分岐して室内機５ａ〜５ｄの各ガス側閉鎖弁５４ａ〜５４ｄにそれぞれ接続されている。このように、室外機２と室内機５ａ〜５ｄとが第１液管８ａ、第２液管８ｂ、第３液管８ｃ、第４液管８ｄ、および、ガス管９で接続されて、空気調和装置１の冷媒回路１０が構成されている。 Each of the above components is connected as follows. One end of the first liquid pipe 8a is connected to the first liquid side closing valve 28a of the outdoor unit 2, and the other end is connected to the liquid side closing valve 53a of the indoor unit 5a. Further, one end of the second liquid pipe 8b is connected to the second liquid side closing valve 28b of the outdoor unit 2, and the other end is connected to the liquid side closing valve 53b of the indoor unit 5b. Further, one end of the third liquid pipe 8c is connected to the third liquid side closing valve 28c of the outdoor unit 2, and the other end is connected to the liquid side closing valve 53c of the indoor unit 5c. Further, one end of the fourth liquid pipe 8d is connected to the fourth liquid side closing valve 28d of the outdoor unit 2, and the other end is connected to the liquid side closing valve 53d of the indoor unit 5d. Further, one end of the gas pipe 9 is connected to the gas side closing valve 29 of the outdoor unit 2, and the other end is branched and connected to the gas side closing valves 54a to 54d of the indoor units 5a to 5d. In this way, the outdoor unit 2 and the indoor units 5a to 5d are connected by the first liquid pipe 8a, the second liquid pipe 8b, the third liquid pipe 8c, the fourth liquid pipe 8d, and the gas pipe 9, and the air is connected. The refrigerant circuit 10 of the harmonizing device 1 is configured.

まず、図１（Ａ）を用いて、室外機２について説明する。室外機２は、圧縮機２１と、四方弁２２と、室外熱交換器２３と、第１室外膨張弁２４ａと、第２室外膨張弁２４ｂと、第３室外膨張弁２４ｃと、第４室外膨張弁２４ｄと、室外ファン２７と、一端に第１液管８ａが接続された第１閉鎖弁２８ａと、一端に第２液管８ｂが接続された第２閉鎖弁２８ｂと、一端に第３液管８ｃが接続された第３閉鎖弁２８ｃと、一端に第４液管８ｄが接続された第４閉鎖弁２８ｄと、一端にガス管９が接続されたガス側閉鎖弁２９と、室外機制御手段２００とを備えている。そして、室外ファン２７および室外機制御手段２００を除くこれら各装置が以下で詳述する各冷媒配管で相互に接続されて、冷媒回路１０の一部をなす室外機冷媒回路２０を構成している。 First, the outdoor unit 2 will be described with reference to FIG. 1 (A). The outdoor unit 2 includes a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, a first outdoor expansion valve 24a, a second outdoor expansion valve 24b, a third outdoor expansion valve 24c, and a fourth outdoor expansion. A valve 24d, an outdoor fan 27, a first closing valve 28a to which a first liquid pipe 8a is connected to one end, a second closing valve 28b to which a second liquid pipe 8b is connected to one end, and a third liquid at one end. A third closing valve 28c to which a pipe 8c is connected, a fourth closing valve 28d to which a fourth liquid pipe 8d is connected to one end, a gas side closing valve 29 to which a gas pipe 9 is connected to one end, and an outdoor unit control. It is equipped with means 200. Then, each of these devices except the outdoor fan 27 and the outdoor unit control means 200 is connected to each other by the refrigerant pipes described in detail below to form the outdoor unit refrigerant circuit 20 forming a part of the refrigerant circuit 10. ..

圧縮機２１は、インバータにより回転数が制御される図示しないモータによって駆動されることで運転容量を可変できる能力可変型圧縮機である。圧縮機２１の冷媒吐出側は、後述する四方弁２２のポートａと吐出管４１で接続されている。また、圧縮機２１の冷媒吸入側は、後述する四方弁２２のポートｃと吸入管４２で接続されている。 The compressor 21 is a variable capacity compressor whose operating capacity can be changed by being driven by a motor (not shown) whose rotation speed is controlled by an inverter. The refrigerant discharge side of the compressor 21 is connected to the port a of the four-way valve 22 described later by a discharge pipe 41. Further, the refrigerant suction side of the compressor 21 is connected to the port c of the four-way valve 22, which will be described later, by a suction pipe 42.

四方弁２２は、冷媒の流れる方向を切り換えるための流路切替手段であり、ａ、ｂ、ｃ、ｄの４つのポートを備えている。ポートａは、圧縮機２１の冷媒吐出側と吐出管４１で接続されている。ポートｄは、室外熱交換器２３の一方の冷媒出入口と冷媒配管４３で接続されている。ポートｃは、圧縮機２１の冷媒吸入側と吸入管４２で接続されている。そして、ポートｂは、ガス側閉鎖弁２９と室外機ガス管４４で接続されている。 The four-way valve 22 is a flow path switching means for switching the flow direction of the refrigerant, and includes four ports a, b, c, and d. The port a is connected to the refrigerant discharge side of the compressor 21 by a discharge pipe 41. The port d is connected to one of the refrigerant inlets and outlets of the outdoor heat exchanger 23 by a refrigerant pipe 43. The port c is connected to the refrigerant suction side of the compressor 21 by a suction pipe 42. The port b is connected to the gas side closing valve 29 by the outdoor unit gas pipe 44.

室外熱交換器２３は、後述する室外ファン２７の回転により図示しない吸込口から室外機２の内部に取り込まれた外気と冷媒とを熱交換させるものである。室外熱交換器２３の一方の冷媒出入口は上述したように冷媒配管４３で四方弁２２のポートｄに接続され、他方の冷媒出入口には室外機液管４５の一端が接続されている。室外熱交換器２３は、冷媒回路１０が冷房サイクルとなる場合は凝縮器として機能し、冷媒回路１０が暖房サイクルとなる場合は蒸発器として機能する。 The outdoor heat exchanger 23 exchanges heat between the outside air taken into the outdoor unit 2 and the refrigerant from a suction port (not shown) by the rotation of the outdoor fan 27 described later. As described above, one refrigerant inlet / outlet of the outdoor heat exchanger 23 is connected to the port d of the four-way valve 22 by the refrigerant pipe 43, and one end of the outdoor unit liquid pipe 45 is connected to the other refrigerant inlet / outlet. The outdoor heat exchanger 23 functions as a condenser when the refrigerant circuit 10 is in the cooling cycle, and functions as an evaporator when the refrigerant circuit 10 is in the heating cycle.

室外機液管４５の他端には、第１液分管４６ａの一端と第２液分管４６ｂの一端と第３液分管４６ｃの一端と第４液分管４６ｄの一端が各々接続されている。また、第１液分管４６ａの他端は第１液側閉鎖弁２８ａと接続され、第２液分管４６ｂの他端は第２液側閉鎖弁２８ｂと接続され、第３液分管４６ｃの他端は第３液側閉鎖弁２８ｃと接続され、第４液分管４６ｄの他端は第４液側閉鎖弁２８ｄと接続されている。 One end of the first liquid dividing pipe 46a, one end of the second liquid dividing pipe 46b, one end of the third liquid dividing pipe 46c, and one end of the fourth liquid dividing pipe 46d are connected to the other end of the outdoor unit liquid pipe 45, respectively. Further, the other end of the first liquid branch pipe 46a is connected to the first liquid side closing valve 28a, the other end of the second liquid branch pipe 46b is connected to the second liquid side closing valve 28b, and the other end of the third liquid branch pipe 46c. Is connected to the third liquid side closing valve 28c, and the other end of the fourth liquid branch pipe 46d is connected to the fourth liquid side closing valve 28d.

第１液分管４６ａには、第１室外膨張弁２４ａが設けられている。また、第２液分管４６ｂには、第２室外膨張弁２４ｂが設けられている。また、第３液分管４６ｃには、第３室外膨張弁２４ｃが設けられている。さらには、第４液分管４６ｄには、第４室外膨張弁２４ｄが設けられている。 The first liquid branch pipe 46a is provided with a first outdoor expansion valve 24a. Further, the second liquid branch pipe 46b is provided with a second outdoor expansion valve 24b. Further, the third liquid branch pipe 46c is provided with a third outdoor expansion valve 24c. Further, the fourth liquid branch pipe 46d is provided with a fourth outdoor expansion valve 24d.

第１室外膨張弁２４ａ、第２室外膨張弁２４ｂ、第３室外膨張弁２４ｃ、第４室外膨張弁２４ｄは、各々電子膨張弁である。第１室外膨張弁２４ａの開度を調節することで、後述する室内機５ａの室内熱交換器５１ａを流れる冷媒量を調節する。第２室外膨張弁２４ｂの開度を調節することで、後述する室内機５ｂの室内熱交換器５１ｂを流れる冷媒量を調節する。第３室外膨張弁２４ｃの開度を調節することで、後述する室内機５ｃの室内熱交換器５１ｃを流れる冷媒量を調節する。第４室外膨張弁２４ｄの開度を調節することで、後述する室内機５ｄの室内熱交換器５１ｄを流れる冷媒量を調節する。 The first outdoor expansion valve 24a, the second outdoor expansion valve 24b, the third outdoor expansion valve 24c, and the fourth outdoor expansion valve 24d are electronic expansion valves, respectively. By adjusting the opening degree of the first outdoor expansion valve 24a, the amount of refrigerant flowing through the indoor heat exchanger 51a of the indoor unit 5a described later is adjusted. By adjusting the opening degree of the second outdoor expansion valve 24b, the amount of refrigerant flowing through the indoor heat exchanger 51b of the indoor unit 5b, which will be described later, is adjusted. By adjusting the opening degree of the third outdoor expansion valve 24c, the amount of refrigerant flowing through the indoor heat exchanger 51c of the indoor unit 5c described later is adjusted. By adjusting the opening degree of the fourth outdoor expansion valve 24d, the amount of refrigerant flowing through the indoor heat exchanger 51d of the indoor unit 5d, which will be described later, is adjusted.

室外ファン２７は、樹脂材で形成されており、室外熱交換器２３の近傍に配置されている。室外ファン２７は、図示しないファンモータによって回転することで、図示しない吸込口から室外機２の内部へ外気を取り込み、室外熱交換器２３において冷媒と熱交換した外気を図示しない吹出口から室外機２の外部へ放出する。 The outdoor fan 27 is made of a resin material and is arranged in the vicinity of the outdoor heat exchanger 23. The outdoor fan 27 is rotated by a fan motor (not shown) to take in outside air from a suction port (not shown) into the outdoor unit 2 and exchange heat with the refrigerant in the outdoor heat exchanger 23 from an outlet (not shown) to the outdoor unit. Release to the outside of 2.

以上説明した構成の他に、室外機２には各種のセンサが設けられている。図１（Ａ）に示すように、吐出管４１には、圧縮機２１から吐出される冷媒の圧力である吐出圧力を検出する高圧センサ３１と、圧縮機２１から吐出される冷媒の温度である吐出温度を検出する吐出温度センサ３３とが設けられている。吸入管４２には、圧縮機２１に吸入される冷媒の圧力である吸入圧力を検出する低圧センサ３２と、圧縮機２１に吸入される冷媒の温度である吸入温度を検出する吸入温度センサ３４とが設けられている。室外熱交換器２３には、室外熱交換器２３の温度を検出する室外熱交温度センサ３５が設けられている。 In addition to the configuration described above, the outdoor unit 2 is provided with various sensors. As shown in FIG. 1A, the discharge pipe 41 has a high pressure sensor 31 that detects the discharge pressure, which is the pressure of the refrigerant discharged from the compressor 21, and the temperature of the refrigerant discharged from the compressor 21. A discharge temperature sensor 33 that detects the discharge temperature is provided. The suction pipe 42 includes a low pressure sensor 32 that detects the suction pressure that is the pressure of the refrigerant sucked into the compressor 21, and a suction temperature sensor 34 that detects the suction temperature that is the temperature of the refrigerant sucked into the compressor 21. Is provided. The outdoor heat exchanger 23 is provided with an outdoor heat exchange temperature sensor 35 that detects the temperature of the outdoor heat exchanger 23.

第１液分管４６ａにおける、第１室外膨張弁２４ａと第１液側閉鎖弁２８ａとの間には、この間の第１液分管４６ａを流れる冷媒の温度を検出する第１液温度センサ３８ａが設けられている。第２液分管４６ｂにおける、第２室外膨張弁２４ｂと第２液側閉鎖弁２８ｂとの間には、この間の第２液分管４６ｂを流れる冷媒の温度を検出する第２液温度センサ３８ｂが設けられている。第３室外膨張弁２４ｃと第３液側閉鎖弁２８ｃとの間には、この間の第３液分管４６ｃを流れる冷媒の温度を検出する第３液温度センサ３８ｃが設けられている。第４室外膨張弁２４ｄと第４液側閉鎖弁２８ｄとの間には、この間の第４液分管４６ｄを流れる冷媒の温度を検出する第４液温度センサ３８ｄが設けられている。そして、室外機２の図示しない吸込口付近には、室外機２内に流入する外気の温度、すなわち外気温度を検出する外気温度センサ１００が備えられている。 A first liquid temperature sensor 38a for detecting the temperature of the refrigerant flowing through the first liquid dividing pipe 46a between the first outdoor expansion valve 24a and the first liquid side closing valve 28a in the first liquid dividing pipe 46a is provided. Has been done. A second liquid temperature sensor 38b for detecting the temperature of the refrigerant flowing through the second liquid dividing pipe 46b between the second outdoor expansion valve 24b and the second liquid side closing valve 28b in the second liquid dividing pipe 46b is provided. Has been done. Between the third outdoor expansion valve 24c and the third liquid side closing valve 28c, a third liquid temperature sensor 38c that detects the temperature of the refrigerant flowing through the third liquid branch pipe 46c between them is provided. Between the 4th outdoor expansion valve 24d and the 4th liquid side closing valve 28d, a 4th liquid temperature sensor 38d for detecting the temperature of the refrigerant flowing through the 4th liquid branch pipe 46d between them is provided. An outside air temperature sensor 100 for detecting the temperature of the outside air flowing into the outdoor unit 2, that is, the outside air temperature is provided in the vicinity of the suction port (not shown) of the outdoor unit 2.

また、室外機２には、室外機制御手段２００が備えられている。室外機制御手段２００は、室外機２の図示しない電装品箱に格納された制御基板に搭載されており、図１（Ｂ）に示すように、ＣＰＵ２１０と、記憶部２２０と、通信部２３０とを備えている。 Further, the outdoor unit 2 is provided with an outdoor unit control means 200. The outdoor unit control means 200 is mounted on a control board housed in an electrical component box (not shown) of the outdoor unit 2, and as shown in FIG. 1B, the CPU 210, the storage unit 220, and the communication unit 230 It has.

記憶部２２０は、ＲＯＭやＲＡＭで構成されており、室外機２の制御プログラムや各種センサからの検出信号に対応した検出値、圧縮機２１や室外ファン２７の制御状態、後述する各種テーブル等を記憶する。通信部２３０は、室内機５ａ〜５ｄとの通信を行うインターフェイスである。 The storage unit 220 is composed of a ROM and a RAM, and stores detection values corresponding to the control program of the outdoor unit 2 and detection signals from various sensors, the control state of the compressor 21 and the outdoor fan 27, various tables described later, and the like. Remember. The communication unit 230 is an interface for communicating with the indoor units 5a to 5d.

ＣＰＵ２１０は、各種センサでの検出値を取り込むとともに、室内機５ａ〜５ｄから送信される運転開始／停止信号や運転情報（設定温度や室内温度等）を含んだ運転情報信号が通信部２３０を介して入力される。ＣＰＵ２１０は、これら取り込んだ各種検出値や入力された各種情報に基づいて、第１室外膨張弁２４ａ、第２室外膨張弁２４ｂ、第３室外膨張弁２４ｃおよび第４室外膨張弁２４ｄの開度制御や、圧縮機２１や室外ファン２７の駆動制御、四方弁２２の切り換え制御を行う。また、ＣＰＵ２１０は、図１（Ｃ）に示すように、着霜量判定手段２１１、パルス算出手段２１２、膨張弁制御手段２１３を備えている。これらは、後述する制御で用いられる。 The CPU 210 captures the values detected by various sensors, and the operation information signal including the operation start / stop signal and the operation information (set temperature, room temperature, etc.) transmitted from the indoor units 5a to 5d is transmitted via the communication unit 230. Is entered. The CPU 210 controls the opening degree of the first outdoor expansion valve 24a, the second outdoor expansion valve 24b, the third outdoor expansion valve 24c, and the fourth outdoor expansion valve 24d based on the various detected values taken in and the various input information. It also controls the drive of the compressor 21 and the outdoor fan 27, and controls the switching of the four-way valve 22. Further, as shown in FIG. 1C, the CPU 210 includes a frost formation amount determining means 211, a pulse calculating means 212, and an expansion valve controlling means 213. These are used in the control described later.

次に、４台の室内機５ａ〜５ｄについて説明する。尚、室内機５ａ〜５ｄの構成は全て同じであるため、以下の説明では、室内機５ａの構成についてのみ説明を行い、その他の室内機５ｂ、５ｃ、５ｄについては説明を省略する。また、図１（Ａ）では、室内機５ａの構成装置に付与した番号の末尾をａからｂ、ｃおよびｄにそれぞれ変更したものが、室外機５ａの構成装置と対応する室内機５ｂ、５ｃ、５ｄの構成装置となる。 Next, the four indoor units 5a to 5d will be described. Since the configurations of the indoor units 5a to 5d are all the same, in the following description, only the configuration of the indoor unit 5a will be described, and the description of the other indoor units 5b, 5c, and 5d will be omitted. Further, in FIG. 1A, the numbers assigned to the constituent devices of the indoor unit 5a are changed from a to b, c and d, respectively, and the indoor units 5b and 5c corresponding to the constituent devices of the outdoor unit 5a are shown. It becomes a constituent device of 5d.

室内機５ａは、室内熱交換器５１ａと、第１液管８ａがそれぞれ接続された液側閉鎖弁５３ａおよび分岐したガス管９の他端がそれぞれ接続されたガス側閉鎖弁５４ａと、室内ファン５５ａと、室内機制御手段５００ａとを備えている。そして、室内ファン５５ａおよび室内機制御手段５００ａを除くこれら各装置が以下で詳述する各冷媒配管で相互に接続されて、冷媒回路１０の一部をなす室内機冷媒回路５０ａを構成している。 The indoor unit 5a includes an indoor heat exchanger 51a, a liquid side closing valve 53a to which the first liquid pipe 8a is connected, a gas side closing valve 54a to which the other end of the branched gas pipe 9 is connected, and an indoor fan. It includes 55a and indoor unit control means 500a. Then, each of these devices except the indoor fan 55a and the indoor unit control means 500a is connected to each other by the refrigerant pipes described in detail below to form the indoor unit refrigerant circuit 50a forming a part of the refrigerant circuit 10. ..

室内熱交換器５１ａは、後述する室内ファン５５ａの回転により室内機５ａに備えられた図示しない吸込口から室内機５ａの内部に取り込まれた室内空気と冷媒を熱交換させるものであり、一方の冷媒出入口が液側閉鎖弁５３ａに室内機液管７１ａで接続され、他方の冷媒出入口がガス側閉鎖弁５４ａに室内機ガス管７２ａで接続されている。室内熱交換器５１ａは、室内機５ａが冷房運転を行う場合は蒸発器として機能し、室内機５ａが暖房運転を行う場合は凝縮器として機能する。 The indoor heat exchanger 51a exchanges heat between the indoor air taken into the indoor unit 5a and the refrigerant from a suction port (not shown) provided in the indoor unit 5a by rotating the indoor fan 55a, which will be described later. The refrigerant inlet / outlet is connected to the liquid side closing valve 53a by the indoor unit liquid pipe 71a, and the other refrigerant inlet / outlet is connected to the gas side closing valve 54a by the indoor unit gas pipe 72a. The indoor heat exchanger 51a functions as an evaporator when the indoor unit 5a performs a cooling operation, and functions as a condenser when the indoor unit 5a performs a heating operation.

室内ファン５５ａは、室内熱交換器５１ａの近傍に配置される樹脂材で形成されたクロスフローファンであり、図示しないファンモータによって回転することで、図示しない吸込口から室内機５ａの内部に室内空気を取り込み、室内熱交換器５１ａにおいて冷媒と熱交換した室内空気を室内機５ａに備えられた図示しない吹出口から室内へ供給する。 The indoor fan 55a is a cross-flow fan made of a resin material arranged in the vicinity of the indoor heat exchanger 51a, and is rotated by a fan motor (not shown) to enter the interior of the indoor unit 5a from a suction port (not shown). The indoor air that takes in air and exchanges heat with the refrigerant in the indoor heat exchanger 51a is supplied into the room from an outlet (not shown) provided in the indoor unit 5a.

以上説明した構成の他に、室内機５ａには各種のセンサが設けられている。室内熱交換器５１ａには、室内熱交換器５１ａの温度を検出する室内熱交温度センサ６１ａが設けられている。また、室内機ガス管７２ａには第１ガス温度センサ６３ａが設けられている。さらに、室内機５ａの図示しない吸込口付近には、室内機５ａ内に流入する室内空気の温度、すなわち室内温度を検出する室内温度センサ６２ａが備えられている。 In addition to the configuration described above, the indoor unit 5a is provided with various sensors. The indoor heat exchanger 51a is provided with an indoor heat exchange temperature sensor 61a that detects the temperature of the indoor heat exchanger 51a. Further, the indoor unit gas pipe 72a is provided with a first gas temperature sensor 63a. Further, an indoor temperature sensor 62a for detecting the temperature of the indoor air flowing into the indoor unit 5a, that is, the indoor temperature is provided in the vicinity of the suction port (not shown) of the indoor unit 5a.

また、室内機５ａには、室内機制御手段５００ａが備えられている。制御手段５００ａは、室内機５ａの図示しない電装品箱に格納された制御基板に搭載されており、図１（Ｂ）に示すように、ＣＰＵ５１０ａと、記憶部５２０ａと、通信部５３０ａとを備えている。 Further, the indoor unit 5a is provided with an indoor unit control means 500a. The control means 500a is mounted on a control board housed in an electrical component box (not shown) of the indoor unit 5a, and includes a CPU 510a, a storage unit 520a, and a communication unit 530a as shown in FIG. 1 (B). ing.

記憶部５２０ａは、ＲＯＭやＲＡＭで構成されており、室内機５ａの制御プログラムや各種センサからの検出信号に対応した検出値、使用者による空調運転に関する設定情報等を記憶する。通信部５３０ａは、室外機２および他の室内機５ｂ、５ｃとの通信を行うインターフェイスである。 The storage unit 520a is composed of a ROM and a RAM, and stores a control program of the indoor unit 5a, detection values corresponding to detection signals from various sensors, setting information related to air conditioning operation by the user, and the like. The communication unit 530a is an interface for communicating with the outdoor unit 2 and other indoor units 5b and 5c.

ＣＰＵ５１０ａは、各種センサでの検出値を取り込むとともに、使用者が図示しないリモコンを操作して設定した運転条件やタイマー運転設定等を含んだ信号が図示しないリモコン受光部を介して入力される。ＣＰＵ５１０ａは、これら取り込んだ各種検出値や入力された各種情報に基づいて室内ファン５５ａの駆動制御を行う。また、ＣＰＵ５１０ａは、運転開始／停止信号や運転情報（設定温度や室内温度等）を含んだ運転情報信号を、通信部５３０ａを介して室外機２に送信する。 The CPU 510a captures the detection values of various sensors, and a signal including operating conditions and timer operation settings set by the user by operating a remote controller (not shown) is input via a remote controller light receiving unit (not shown). The CPU 510a controls the drive of the indoor fan 55a based on the various detected values taken in and the various input information. Further, the CPU 510a transmits an operation information signal including an operation start / stop signal and operation information (set temperature, room temperature, etc.) to the outdoor unit 2 via the communication unit 530a.

次に、本実施形態における空気調和装置１の空調運転時の冷媒回路１０における冷媒の流れや各部の動作について、図１（Ａ）を用いて説明する。尚、以下の説明では、室内機５ａ〜５ｄが暖房運転を行う場合について説明し、冷房運転／除霜運転を行う場合については詳細な説明を省略する。また、図１（Ａ）における矢印は、暖房運転時の冷媒の流れを示している。 Next, the flow of the refrigerant and the operation of each part in the refrigerant circuit 10 during the air conditioning operation of the air conditioning device 1 in the present embodiment will be described with reference to FIG. 1 (A). In the following description, the case where the indoor units 5a to 5d perform the heating operation will be described, and the detailed description will be omitted when the indoor units 5a to 5d perform the cooling operation / defrosting operation. Further, the arrow in FIG. 1A indicates the flow of the refrigerant during the heating operation.

図１（Ａ）に示すように、室内機５ａ〜５ｄが暖房運転を行う場合、つまり、冷媒回路１０が暖房サイクルとなる場合は、室外機２では、四方弁２２が実線で示す状態、すなわち、四方弁２２のポートａとポートｂとが連通するよう、また、ポートｄとポートｃとが連通するよう、切り換えられる。これにより、室外熱交換器２３が蒸発器として機能するとともに、室内熱交換器５１ａ〜５１ｄが凝縮器として機能する。 As shown in FIG. 1A, when the indoor units 5a to 5d perform the heating operation, that is, when the refrigerant circuit 10 is in the heating cycle, in the outdoor unit 2, the four-way valve 22 is shown by a solid line, that is, , The port a and the port b of the four-way valve 22 are switched to communicate with each other, and the port d and the port c are switched to communicate with each other. As a result, the outdoor heat exchanger 23 functions as an evaporator, and the indoor heat exchangers 51a to 51d function as condensers.

圧縮機２１から吐出された高圧の冷媒は、吐出管４１から四方弁２２を介して室外機ガス管４４に流入し、室外機ガス管４４からガス側閉鎖弁２９を介してガス管９に流入する。ガス管９に流入した冷媒は分岐して、ガス側閉鎖弁５４ａ〜５４ｄを介して室内機５ａ〜５ｄに流入する。 The high-pressure refrigerant discharged from the compressor 21 flows from the discharge pipe 41 into the outdoor unit gas pipe 44 via the four-way valve 22, and flows from the outdoor unit gas pipe 44 into the gas pipe 9 via the gas side closing valve 29. To do. The refrigerant that has flowed into the gas pipe 9 branches and flows into the indoor units 5a to 5d via the gas side closing valves 54a to 54d.

室内機５ａ〜５ｄに流入した冷媒は、室内機ガス管７２ａ〜７２ｄを流れて室内熱交換器５１ａ〜５１ｄに流入する。室内熱交換器５１ａ〜５１ｄに流入した冷媒は、室内ファン５５ａ〜５５ｄの回転により図示しない吸込口から室内機５ａ〜５ｄの内部に取り込まれた室内空気と熱交換を行って凝縮する。このように、室内熱交換器５１ａ〜５１ｄが凝縮器として機能し、室内熱交換器５１ａ〜５１ｄで冷媒と熱交換を行って暖められた室内空気が図示しない吹出口から室内機５ａ〜５ｄが設置されている部屋に吹き出されることによって、各部屋の暖房が行われる。 The refrigerant that has flowed into the indoor units 5a to 5d flows through the indoor unit gas pipes 72a to 72d and flows into the indoor heat exchangers 51a to 51d. The refrigerant that has flowed into the indoor heat exchangers 51a to 51d exchanges heat with the indoor air taken into the indoor units 5a to 5d from a suction port (not shown) due to the rotation of the indoor fans 55a to 55d to condense. In this way, the indoor heat exchangers 51a to 51d function as condensers, and the indoor heat exchangers 51a to 51d exchange heat with the refrigerant to heat the indoor air, and the indoor units 5a to 5d are connected from an outlet (not shown). Each room is heated by blowing it into the installed room.

室内熱交換器５１ａ〜５１ｄから流出した冷媒は室内機液管７１ａ〜７１ｄを流れ、液側閉鎖弁５３ａ〜５３ｄを介して第１液管８ａ、第２液管８ｂ、第３液管８ｃ、および第４液管８ｄに流入する。第１液管８ａ、第２液管８ｂ、第３液管８ｃ、および第４液管８ｄから第１液側閉鎖弁２８ａ、第２液側閉鎖弁２８ｂ、第３液側閉鎖弁２８ｃ、および第４液側閉鎖弁２８ｄを介して室外機２に流入した冷媒は、第１液分管４６ａ、第２液分管４６ｂ、第３液分管４６ｃ、および第４液分管４６ｄを流れて第１室外膨張弁２４ａ、第２室外膨張弁２４ｂ、第３室外膨張弁２４ｃ、および第４室外膨張弁２４ｄを通過して減圧された後、室外機液管４５に流入する。 The refrigerant flowing out from the indoor heat exchangers 51a to 51d flows through the indoor unit liquid pipes 71a to 71d, and passes through the liquid side closing valves 53a to 53d to the first liquid pipe 8a, the second liquid pipe 8b, and the third liquid pipe 8c. And flows into the fourth liquid pipe 8d. The first liquid pipe 8a, the second liquid pipe 8b, the third liquid pipe 8c, and the fourth liquid pipe 8d to the first liquid side closing valve 28a, the second liquid side closing valve 28b, the third liquid side closing valve 28c, and The refrigerant that has flowed into the outdoor unit 2 via the fourth liquid side closing valve 28d flows through the first liquid branch pipe 46a, the second liquid branch pipe 46b, the third liquid branch pipe 46c, and the fourth liquid branch pipe 46d and expands to the first outdoor side. After passing through the valve 24a, the second outdoor expansion valve 24b, the third outdoor expansion valve 24c, and the fourth outdoor expansion valve 24d, the pressure is reduced, and then the pressure flows into the outdoor unit liquid pipe 45.

室外機液管４５から室外熱交換器２３に流入した冷媒は、室外ファン２７の回転により室外機２の内部に取り込まれた外気と熱交換を行って蒸発する。室外熱交換器２３から流出した冷媒は、冷媒配管４３を流れて四方弁２２に流入し四方弁２２から吸入管４２へと流れ、圧縮機２１に吸入されて再び圧縮される。 The refrigerant flowing from the outdoor unit liquid pipe 45 into the outdoor heat exchanger 23 evaporates by exchanging heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 27. The refrigerant flowing out of the outdoor heat exchanger 23 flows through the refrigerant pipe 43, flows into the four-way valve 22, flows from the four-way valve 22 to the suction pipe 42, is sucked into the compressor 21, and is compressed again.

尚、室内機５ａ〜５ｄが冷房運転あるいは除霜運転を行う場合、つまり、冷媒回路１０が冷房サイクルとなる場合は、室外機２では、四方弁２２が破線で示す状態、すなわち、四方弁２２のポートａとポートｄとが連通するよう、また、ポートｃとポートｂとが連通するよう、切り換えられる。これにより、室外熱交換器２３が凝縮器として機能するとともに、室内熱交換器５１ａ〜５１ｄが蒸発器として機能する。 When the indoor units 5a to 5d perform a cooling operation or a defrosting operation, that is, when the refrigerant circuit 10 is in a cooling cycle, the four-way valve 22 is shown by a broken line in the outdoor unit 2, that is, the four-way valve 22. It is switched so that the port a and the port d of the above can communicate with each other, and the port c and the port b can communicate with each other. As a result, the outdoor heat exchanger 23 functions as a condenser, and the indoor heat exchangers 51a to 51d function as an evaporator.

次に、図１〜図４を用いて、本実施形態の空気調和装置１が除霜運転を行っているときの、第１室外膨張弁２４ａ、第２室外膨張弁２４ｂ、第３室外膨張弁２４ｃ、および第４室外膨張弁２４ｄの開度制御について詳細に説明する。 Next, using FIGS. 1 to 4, the first outdoor expansion valve 24a, the second outdoor expansion valve 24b, and the third outdoor expansion valve when the air conditioner 1 of the present embodiment is performing the defrosting operation. The opening degree control of the 24c and the fourth outdoor expansion valve 24d will be described in detail.

尚、以下の説明では、暖房運転時において室外熱交温度センサ３５で検出する室外熱交換器２３での蒸発温度をＴｃ、外気温度センサ１００で検出する外気温度をＴｏとする。 In the following description, the evaporation temperature of the outdoor heat exchanger 23 detected by the outdoor heat exchange temperature sensor 35 during the heating operation is Tc, and the outside air temperature detected by the outside air temperature sensor 100 is To.

また、室外熱交温度センサ３５で検出する室外熱交換器の蒸発温度Ｔｅは所定時間毎（例えば、３０秒）に常時検出され、記憶部２２０に記憶される。また、今回検出した室外熱交換器の蒸発温度Ｔｅと前回検出した蒸発温度Ｔｅ０の差（Ｔｅ−Ｔｅ０）である蒸発温度低下幅をΔＴｅする。また、ＣＰＵ２１０では、圧縮機２１が前回運転を開始してからの連続運転積算時間を計測しており、この連続運転積算時間をｔとする。 Further, the evaporation temperature Te of the outdoor heat exchanger detected by the outdoor heat exchange temperature sensor 35 is constantly detected at predetermined time intervals (for example, 30 seconds) and stored in the storage unit 220. Further, the evaporation temperature decrease width, which is the difference (Te-Te0) between the evaporation temperature Te of the outdoor heat exchanger detected this time and the evaporation temperature Te0 detected last time, is ΔTe. Further, the CPU 210 measures the continuous operation integrated time since the compressor 21 started the previous operation, and this continuous operation integrated time is set to t.

空気調和装置１が暖房運転を行っているとき、以下の条件のうちいずれかを満たした場合、ＣＰＵ２１０は、四方弁２２の切り替え制御を行い、除霜運転を開始する。
（１）室外熱交換器の蒸発温度Ｔｃが閾温度Ｔｅ１以下
（２）室外熱交換器の蒸発温度Ｔｃが閾温度Ｔｅ２以下であって、蒸発温度低下幅ΔＴｅが閾値ΔＴｅｔ以上
（３）室外熱交換器の蒸発温度Ｔｃが閾温度Ｔｅ２以下であって、圧縮機２１の連続運転積算時間ｔが閾時間ｔ１以上
閾温度Ｔｅ１は、暖房運転中の室外熱交換器２３に霜が付着している可能性が高くなる室外熱交換器２３の温度であって、予め試験等によって求められて記憶部２２０に記憶されている。尚、閾温度Ｔｅ１は、外気温度センサ１００で検出する外気温度Ｔｏに応じて変化させても良い。
また、閾温度Ｔｅ２は、閾温度Ｔｅ１よりも所定温度（例えば２℃）高い値が設定される。
また、閾値ΔＴｅｔと閾時間ｔ０は、予め試験等によって求められて記憶部２２０に記憶されている。
従来、室内機５ａ〜５ｄのうち、例えば室内機５ｂ〜５ｄが運転停止している場合、室内機５ｂ〜５ｄに対応する膨張弁２４ｂ〜２４ｄは冷媒音の発生を防ぐため全閉となるように開度制御され、その後除霜運転が行われても全閉の状態を維持していた。そのため、除霜運転時には室内機５ａの室内熱交換器５１ａでしか吸熱されず、室外熱交換器２３における放熱量が少なくなる。よって、除霜に費やす時間が長くなってしまうだけでなく、冷媒流量が減ることにより冷媒回路内の低圧が大きく低下し、この結果、低圧保護動作によって空気調和装置が異常停止してしまうという不具合があった。
これを回避するために、除霜運転時、運転停止中の室内機５ｂ〜５ｄに対応する膨張弁２４ｂ〜２４ｄを全開に制御し、運転停止中の室内機の台数が多い場合であっても除霜運転時に室内機の室内熱交換器で吸熱される熱を十分に確保できるようにする方法がある。 When any of the following conditions is satisfied when the air conditioner 1 is performing the heating operation, the CPU 210 controls the switching of the four-way valve 22 and starts the defrosting operation.
(1) The evaporation temperature Tc of the outdoor heat exchanger is the threshold temperature Te1 or less (2) The evaporation temperature Tc of the outdoor heat exchanger is the threshold temperature Te2 or less, and the evaporation temperature decrease width ΔTe is the threshold ΔTet or more (3) Outdoor heat The evaporation temperature Tc of the exchanger is equal to or less than the threshold temperature Te2, and the continuous operation integrated time t of the compressor 21 is equal to or greater than the threshold time t1. At the threshold temperature Te1, frost is attached to the outdoor heat exchanger 23 during the heating operation. The temperature of the outdoor heat exchanger 23, which is highly likely, is determined in advance by a test or the like and is stored in the storage unit 220. The threshold temperature Te1 may be changed according to the outside air temperature To detected by the outside air temperature sensor 100.
Further, the threshold temperature Te2 is set to a value higher than the threshold temperature Te1 by a predetermined temperature (for example, 2 ° C.).
Further, the threshold value ΔTet and the threshold time t0 are obtained in advance by a test or the like and stored in the storage unit 220.
Conventionally, among the indoor units 5a to 5d, for example, when the indoor units 5b to 5d are stopped, the expansion valves 24b to 24d corresponding to the indoor units 5b to 5d are fully closed to prevent the generation of refrigerant noise. The opening was controlled, and the fully closed state was maintained even after the defrosting operation was performed. Therefore, during the defrosting operation, heat is absorbed only by the indoor heat exchanger 51a of the indoor unit 5a, and the amount of heat radiated by the outdoor heat exchanger 23 is reduced. Therefore, not only the time spent for defrosting becomes long, but also the low pressure in the refrigerant circuit drops significantly due to the decrease in the refrigerant flow rate, and as a result, the air conditioner abnormally stops due to the low pressure protection operation. was there.
In order to avoid this, during the defrosting operation, the expansion valves 24b to 24d corresponding to the indoor units 5b to 5d that are stopped are controlled to be fully open, and even when the number of indoor units that are stopped is large. There is a method of ensuring sufficient heat absorbed by the indoor heat exchanger of the indoor unit during the defrosting operation.

しかし、運転停止中の室内機５ｂ〜５ｄに対応する膨張弁２４ｂ〜２４ｄの開度を全開にすると、運転停止中の室内機５ｂ〜５ｄの室内熱交換器５１ｂ〜５１ｄ内を流れる冷媒の量が増加する。運転停止中の室内機５ｂ〜５ｄの室内熱交換器５１ｂ〜５１ｄ内を流れる冷媒の量が増加すると、運転停止中の室内機５ｂ〜５ｄから発生する冷媒音が増大し、ユーザに不快感を与えてしまう。
また、除霜運転時、運転停止中の室内機５ｂ〜５ｄに対応する膨張弁２４ｂ〜２４ｄが冷媒音を考慮して予め定めた固定の開度となるように制御する方法も考えられるが、除霜運転時に必要な室内機一台当たりの室内熱交換器５１ｂ〜５１ｄでの吸熱量は、室内機５の接続台数や運転台数によって異なるため、このような方法では着霜量に応じた膨張弁の開度制御に改良の余地がある。 However, when the opening degree of the expansion valves 24b to 24d corresponding to the indoor units 5b to 5d that are stopped is fully opened, the amount of refrigerant flowing in the indoor heat exchangers 51b to 51d of the indoor units 5b to 5d that are stopped. Will increase. When the amount of refrigerant flowing in the indoor heat exchangers 51b to 51d of the indoor units 5b to 5d that are stopped is increased, the refrigerant noise generated from the indoor units 5b to 5d that is stopped is increased, which makes the user uncomfortable. I will give it.
Further, during the defrosting operation, a method of controlling the expansion valves 24b to 24d corresponding to the indoor units 5b to 5d that are stopped so as to have a predetermined fixed opening degree in consideration of the refrigerant noise is also conceivable. Since the amount of heat absorbed by the indoor heat exchangers 51b to 51d per indoor unit required for defrosting operation differs depending on the number of connected indoor units 5 and the number of operating units, such a method expands according to the amount of frost formation. There is room for improvement in valve opening control.

そこで、本発明では、室外熱交換器２３に付着した霜の量（着霜量）を推定し、着霜量および室内機５の運転台数に基づいて停止中の室内機５ｂ〜５ｄに対応する膨張弁２４ｂ〜２４ｄの開度を設定している。これによって、運転停止中の室内機５の台数が多い場合であっても、除霜運転時に室内機５の室内熱交換器５１で吸熱される熱を十分に確保しつつ、運転停止中の室内機５から発生する冷媒音を低減できる。 Therefore, in the present invention, the amount of frost adhering to the outdoor heat exchanger 23 (frost formation amount) is estimated, and the indoor units 5b to 5d that are stopped are supported based on the frost formation amount and the number of operating indoor units 5. The opening degree of the expansion valves 24b to 24d is set. As a result, even when the number of indoor units 5 that are stopped is large, the room that is stopped while sufficiently securing the heat absorbed by the indoor heat exchanger 51 of the indoor unit 5 during the defrosting operation. The refrigerant noise generated from the machine 5 can be reduced.

以下、図２を用いて本発明に関わる処理について詳細に説明する。尚、図２に示すフローチャートでは、ＳＴは処理のステップを表し、これに続く数字はステップ番号を表している。また、図２では、本発明に関わる処理を中心に説明しており、空気調和装置１が除霜運転以外を行うときの処理や、使用者の指示した設定温度や風量などの運転条件に対応した冷媒回路１０の制御、等といった一般的な処理については説明を省略する。 Hereinafter, the process according to the present invention will be described in detail with reference to FIG. In the flowchart shown in FIG. 2, ST represents a processing step, and the number following the ST represents a step number. Further, FIG. 2 mainly describes the processing related to the present invention, and corresponds to the processing when the air conditioner 1 performs other than the defrosting operation and the operating conditions such as the set temperature and the air volume instructed by the user. The description of general processing such as control of the refrigerant circuit 10 is omitted.

図２のフローチャートによる処理は、空気調和装置１の冷媒回路１０が暖房サイクルの状態となっているときに行われる。ＣＰＵ２１０は、室外熱交換器２３が着霜しているか否かを判定する着霜判定を行う（ＳＴ１１）。着霜判定では、前述した条件（１）〜（３）の条件のうちいずれか一つを満たした場合に室外熱交換器２３が着霜したと判断する。室外熱交換器２３が着霜したと判断した場合（ＳＴ１１−ＹＥＳ）、ＣＰＵ２１０は、蒸発温度Ｔｅ、外気温度Ｔｏ、圧縮機２１の回転数Ｎｃｐを用いて室外熱交換器２３に付着した霜の量（着霜量）の度合いを示す着霜レベルＶｆを抽出する（ＳＴ１１）。室外熱交換器２３が着霜していないと判断した場合（ＳＴ１１−ＮＯ）、ステップＳＴ１１を繰り返す。 The process according to the flowchart of FIG. 2 is performed when the refrigerant circuit 10 of the air conditioner 1 is in the heating cycle state. The CPU 210 performs a frost formation determination for determining whether or not the outdoor heat exchanger 23 is frosted (ST11). In the frost formation determination, it is determined that the outdoor heat exchanger 23 has frosted when any one of the above-mentioned conditions (1) to (3) is satisfied. When it is determined that the outdoor heat exchanger 23 has frosted (ST11-YES), the CPU 210 uses the evaporation temperature Te, the outside air temperature To, and the rotation speed Ncp of the compressor 21 to remove the frost adhering to the outdoor heat exchanger 23. The frost formation level Vf indicating the degree of the amount (frost formation amount) is extracted (ST11). When it is determined that the outdoor heat exchanger 23 is not frosted (ST11-NO), step ST11 is repeated.

ステップＳＴ１２では、ＣＰＵ２１０は、着霜判定時に外気温度センサ１００から外気温度Ｔｏを、室外熱交温度センサ３５から蒸発温度Ｔｅを、そして圧縮機２１の回転数Ｎｃｐをそれぞれ取得する。ＣＰＵ２１０は、取得した外気温度Ｔｏと蒸発温度Ｔｅから、外気温度Ｔｏと室外熱交換器２３の蒸発温度Ｔｅとの差（Ｔｏ−Ｔｅ）である温度差ΔＴを抽出する。ＣＰＵ２１０は、温度差ΔＴと圧縮機２１の回転数Ｎｃｐを用いて室外熱交換器２３に付着した霜の量の度合いを示す着霜レベルＶｆを図３に示すテーブルを用いて抽出する。記憶部２２０には、予め試験等により求められた圧縮機２１の回転数Ｎｃｐと着霜レベルＶｆとの対応関係を規定したテーブルが記憶されている。着霜レベルＶｆは、数値が大きい程室外熱交換器２３に付着した霜の量が多いことを示しており、本実施例では１〜５の５段階の数値で表している。着霜判定時の温度差ΔＴが大きい程着霜量が大きい。そのため、温度差ΔＴが大きい程着霜レベルＶｆには大きい数が設定される。また、同じ温度差ΔＴであっても暖房運転中の室外熱交換器２３に流入する冷媒の量が多ければ着霜量も多くなる。そのため、圧縮機２１の回転数Ｎｃｐが高い程着霜レベルＶｆには大きい数が設定される。また、冷媒密度に与える影響を考慮して外気温度Ｔｏに応じて着霜レベルＶｆを変更している。具体的には、当該テーブルは複数の外気温度Ｔｏの範囲に対して用意されており、図３（Ａ）は外気温度がＴｏ＜−２０℃の時のテーブル、図３（Ｂ）は外気温度が−２０℃≦Ｔｏ＜−１０℃の時のテーブル、図３（Ｃ）は外気温度が−１０℃≦Ｔｏの時のテーブルをそれぞれ示す。例えば、外気温度が−１５℃で温度差ΔＴが４ｄｅｇ、圧縮機の回転数Ｎｃｐが８０ｒｐｓの場合は、着霜レベルＶｆは「３」となる。
ステップＳＴ１２の処理を終えたＣＰＵ２１０は、抽出した着霜レベルＶｆと着霜判定時の室内機５の運転台数Ｎｕｏに基づいて停止中の室内機５ｂ〜５ｄに対応する膨張弁２４ｂ〜２４ｄの適正開度を決定する（ＳＴ１３）。詳細には、ＣＰＵ２１０は、図４に示すテーブルを用いて停止中の室内機５ｂ〜５ｄに対応する膨張弁２４ｂ〜２４ｄの適正開度を決定する。記憶部２２０には、予め試験等により求められた着霜レベルＶｆと着霜判定時の室内機５の運転台数Ｎｕｏとの対応関係を規定したテーブルが記憶されている。着霜判定時において、停止中の室内機５が多い程室外熱交換器２３に流れる冷媒の量は少なくなる。そのため、着霜判定時の室内機５の運転台数が少ない程大きい開度が設定されている。例えば、着霜レベルＶｆが「４」、着霜判定時の室内機５の運転台数が「１」の場合における膨張弁２４ｂ〜２４ｄの適正開度は、全閉状態から「２００パルス」を加算した開度となる。 In step ST12, the CPU 210 acquires the outside air temperature To from the outside air temperature sensor 100, the evaporation temperature Te from the outdoor heat exchange temperature sensor 35, and the rotation speed Ncp of the compressor 21 at the time of frost formation determination. The CPU 210 extracts the temperature difference ΔT, which is the difference (To—Te) between the outside air temperature To and the evaporation temperature Te of the outdoor heat exchanger 23, from the acquired outside air temperature To and evaporation temperature Te. The CPU 210 uses the temperature difference ΔT and the rotation speed Ncp of the compressor 21 to extract the frost formation level Vf indicating the degree of the amount of frost adhering to the outdoor heat exchanger 23 using the table shown in FIG. The storage unit 220 stores a table that defines the correspondence between the rotation speed Ncp of the compressor 21 and the frost formation level Vf, which are previously obtained by a test or the like. The larger the value of the frost formation level Vf, the larger the amount of frost adhering to the outdoor heat exchanger 23, and in this embodiment, it is represented by a numerical value of 5 steps from 1 to 5. The larger the temperature difference ΔT at the time of frost formation determination, the larger the frost formation amount. Therefore, the larger the temperature difference ΔT, the larger the frost formation level Vf is set. Further, even if the temperature difference is the same ΔT, if the amount of the refrigerant flowing into the outdoor heat exchanger 23 during the heating operation is large, the amount of frost formation is also large. Therefore, the higher the rotation speed Ncp of the compressor 21, the larger the frost formation level Vf is set. Further, the frost formation level Vf is changed according to the outside air temperature To in consideration of the influence on the refrigerant density. Specifically, the table is prepared for a plurality of outside air temperature To ranges, FIG. 3 (A) is a table when the outside air temperature is To <-20 ° C, and FIG. 3 (B) is an outside air temperature. Shows a table when -20 ° C ≤ To <-10 ° C, and FIG. 3C shows a table when the outside air temperature is -10 ° C ≤ To. For example, when the outside air temperature is −15 ° C., the temperature difference ΔT is 4 deg, and the compressor rotation speed Ncp is 80 rps, the frost formation level Vf is “3”.
The CPU 210 that has completed the process of step ST12 determines the appropriateness of the expansion valves 24b to 24d corresponding to the stopped indoor units 5b to 5d based on the extracted frost level Vf and the operating number Nuo of the indoor unit 5 at the time of frost determination. The opening degree is determined (ST13). Specifically, the CPU 210 uses the table shown in FIG. 4 to determine the appropriate opening degree of the expansion valves 24b to 24d corresponding to the indoor units 5b to 5d that are stopped. The storage unit 220 stores a table that defines the correspondence relationship between the frost formation level Vf obtained in advance by a test or the like and the operating number Nuo of the indoor unit 5 at the time of frost formation determination. At the time of frost formation determination, the more the indoor unit 5 is stopped, the smaller the amount of refrigerant flowing through the outdoor heat exchanger 23. Therefore, the smaller the number of indoor units 5 in operation at the time of frost formation determination, the larger the opening degree is set. For example, when the frost level Vf is "4" and the number of indoor units 5 in operation at the time of frost determination is "1", the appropriate opening degree of the expansion valves 24b to 24d is "200 pulses" added from the fully closed state. It becomes the opening.

ステップＳＴ１３の処理を終えたＣＰＵ２１０は、着霜判定時に停止していた室内機５ｂ〜ｄに対応する膨張弁２４ｂ〜２４ｄの開度をステップＳＴ１３で決定した適正開度に設定しつつ、四方弁２２の切り替え制御を行い、冷房サイクルとして除霜運転を開始する（ＳＴ１４）。詳細には、まず圧縮機２１を停止してから四方弁２２の切り替え制御を行い、膨張弁２４ｂ〜２４ｄの開度を適正開度に設定し、圧縮機２１を起動させる。 The CPU 210 that has completed the process of step ST13 sets the opening degree of the expansion valves 24b to 24d corresponding to the indoor units 5b to d that were stopped at the time of the frost formation determination to the appropriate opening degree determined in step ST13, and sets the four-way valve. The switching control of 22 is performed, and the defrosting operation is started as a cooling cycle (ST14). Specifically, first, the compressor 21 is stopped, then the four-way valve 22 is switched, the opening degrees of the expansion valves 24b to 24d are set to an appropriate opening degree, and the compressor 21 is started.

次に、ＣＰＵ２１０は、ステップＳＴ１４で除霜運転を開始してからの経過時間ｔが所定時間ｔ０（例えば、１５分）となったか否かを判定する（ＳＴ１５）。所定時間ｔ０は、除霜運転の積算時間であり、長く除霜運転を継続していると室内温度が下がっていくので、快適性の低下を最小限にしつつ除霜を行える時間が設定される。経過時間ｔが所定時間ｔ０となった場合（ＳＴ１５−ＹＥＳ）、ＣＰＵ２１０は、四方弁２２の切り替え制御を行い（ＳＴ１６）、暖房サイクルとして暖房運転に復帰する。経過時間ｔが所定時間ｔ０となっていない場合（ＳＴ１５−ＮＯ）、ステップＳＴ１５を繰り返す。 Next, the CPU 210 determines whether or not the elapsed time t since the start of the defrosting operation in step ST14 has reached the predetermined time t0 (for example, 15 minutes) (ST15). The predetermined time t0 is the integrated time of the defrosting operation, and since the indoor temperature drops if the defrosting operation is continued for a long time, the time during which the defrosting can be performed while minimizing the decrease in comfort is set. .. When the elapsed time t becomes the predetermined time t0 (ST15-YES), the CPU 210 controls the switching of the four-way valve 22 (ST16) and returns to the heating operation as a heating cycle. If the elapsed time t is not the predetermined time t0 (ST15-NO), step ST15 is repeated.

以上説明したように、本実施形態の空気調和装置１では、暖房運転中に除霜運転を行うときに、着霜判定時の蒸発温度Ｔｅ、外気温度Ｔｏ、圧縮機２１の回転数Ｎｃｐを用いて室外熱交換器２３に付着した霜の量（着霜量）を推定し、着霜量および室内機５の運転台数に基づいて停止中の室内機５ｂ〜５ｄに対応する膨張弁２４ｂ〜２４ｄの開度を設定している。これによって、運転停止中の室内機５の台数が多い場合であっても、除霜運転時に室内機５の室内熱交換器５１で吸熱される熱を十分に確保しつつ、運転停止中の室内機５から発生する冷媒音を低減できる。 As described above, in the air conditioner 1 of the present embodiment, when the defrosting operation is performed during the heating operation, the evaporation temperature Te at the time of frost formation determination, the outside air temperature To, and the rotation speed Ncp of the compressor 21 are used. The amount of frost adhering to the outdoor heat exchanger 23 (frost formation amount) is estimated, and the expansion valves 24b to 24d corresponding to the stopped indoor units 5b to 5d are based on the frost formation amount and the number of indoor units 5 in operation. The opening degree of is set. As a result, even when the number of indoor units 5 that are stopped is large, the room that is stopped while sufficiently securing the heat absorbed by the indoor heat exchanger 51 of the indoor unit 5 during the defrosting operation. The refrigerant noise generated from the machine 5 can be reduced.

１空気調和装置
２室外機
５ａ〜５ｃ室内機
８ａ〜８ｃ第１〜第３液管
２３室外熱交換器
２４ａ第１室外膨張弁
２４ｂ第２室外膨張弁
２４ｃ第３室外膨張弁
３１高圧センサ
３２低圧センサ
３３吐出温度センサ
３４吸入温度センサ
３５室外熱交温度センサ
1 Air conditioner 2 Outdoor unit 5a to 5c Indoor unit 8a to 8c 1st to 3rd liquid pipes 23 Outdoor heat exchanger 24a 1st outdoor expansion valve 24b 2nd outdoor expansion valve 24c 3rd outdoor expansion valve 31 High pressure sensor 32 Low pressure Sensor 33 Discharge temperature sensor 34 Suction temperature sensor 35 Outdoor heat exchange temperature sensor

Claims

It has a compressor, an outdoor heat exchanger, an outdoor heat exchange temperature detecting means for detecting the outdoor heat exchange temperature which is the temperature of the refrigerant flowing through the outdoor heat exchanger, and an outside air temperature detecting means for detecting the outside air temperature. Outdoor unit and
With an indoor unit having an indoor heat exchanger,
An air conditioner in which a plurality of indoor units are connected in parallel to one outdoor unit by a refrigerant pipe.
Expansion valves connected to each of the indoor units,
A refrigerant circuit in which the refrigerant circulates in the order of the compressor, the indoor heat exchanger, the expansion valve, and the outdoor heat exchanger during the heating operation.
A flow path switching means provided in the refrigerant circuit and switching the flow of the refrigerant so that the refrigerant discharged from the compressor is directed to the outdoor heat exchanger during the defrosting operation.
A control means for controlling the compressor, the expansion valve, and the flow path switching means is provided.
The control means performs a frost formation determination for determining whether or not frost is generated in the outdoor heat exchanger during the heating operation.
When it is determined in the frost formation determination that frost is generated in the outdoor heat exchanger, the amount of frost formation is estimated from at least the outdoor heat exchange temperature and the outside air temperature.
Based on the amount of frost formation and the number of indoor units operating at the time of the frost formation determination, the appropriate opening degree of the expansion valve corresponding to the indoor unit that was stopped at the time of the frost formation determination is determined, and then the removal is performed. Perform a frost operation,
An air conditioner in which the opening degree of the expansion valve corresponding to the indoor unit that was stopped at the time of the frost formation determination during the defrosting operation is set to the appropriate opening degree.

The air conditioner according to claim 1, wherein the amount of frost formation is changed based on the rotation speed of the compressor.