JP2008064381A - Air conditioner - Google Patents

Air conditioner Download PDF

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Publication number
JP2008064381A
JP2008064381A JP2006242740A JP2006242740A JP2008064381A JP 2008064381 A JP2008064381 A JP 2008064381A JP 2006242740 A JP2006242740 A JP 2006242740A JP 2006242740 A JP2006242740 A JP 2006242740A JP 2008064381 A JP2008064381 A JP 2008064381A
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heat exchanger
defrosting
outdoor
heating
heating operation
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JP2006242740A
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JP4272224B2 (en
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Masahiko Watanabe
正彦 渡辺
Makoto Oguri
誠 小栗
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Hitachi Appliances Inc
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Hitachi Appliances Inc
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Priority to JP2006242740A priority Critical patent/JP4272224B2/en
Priority to KR1020070079848A priority patent/KR100846266B1/en
Priority to CNB2007101403531A priority patent/CN100510583C/en
Publication of JP2008064381A publication Critical patent/JP2008064381A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F25B49/025—Motor control arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
    • F25B47/02—Defrosting cycles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2313/00—Compression machines, plants or systems with reversible cycle not otherwise provided for
    • F25B2313/027—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means
    • F25B2313/02741—Compression machines, plants or systems with reversible cycle not otherwise provided for characterised by the reversing means using one four-way valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/11—Fan speed control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2501—Bypass valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2103—Temperatures near a heat exchanger

Abstract

<P>PROBLEM TO BE SOLVED: To simultaneously carry out defrosting and heating in an air conditioner for shortening a defrosting time while ensuring comfortableness inside a room. <P>SOLUTION: The air conditioner having a freezing cycle, which connects a compressor 75, a four-way valve 72, an interior heat exchanger 33, a pressure reducing device 74, and an exterior heat exchanger 73 one another with a refrigerant pipe, is provided with a bypass circuit feeding hot gas flow from a discharge side of the compressor 75 to the exterior heat exchanger 73. In the exterior heat exchanger 73, the refrigerant circuit is divided into an upper portion and a lower portion for constructing a lower heat exchanger 732 and an upper heat exchanger 731 larger than the lower heat exchanger 732. A controller 10 opens/closes main circuit switching mechanism 731a and 713b and bypass switch valves 715a and 715b inversely so that heating is carried out by the upper heat exchanger 731 while defrosting the lower heat exchanger 732 after performing defrosting/heating operation for performing heating by the lower heat exchanger 732 while defrosting the upper heat exchanger 731. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、空気調和機に係り、特に、室外熱交換器の除霜と室内の暖房とを同時に行う空気調和機に好適なものである。   The present invention relates to an air conditioner, and is particularly suitable for an air conditioner that simultaneously performs defrosting of an outdoor heat exchanger and heating of a room.

空気熱源ヒートポンプ空気調和機を暖房運転した場合、室外空気の湿度が高いと室外熱交換器に着霜を生ずる。着霜が生ずると室外熱交換器の通風路が狭まるため、室外熱交換器を循環する室外空気の量が減少する。循環する室外空気の量が減少すると、熱交換量が少なくなるため、これを補おうとする如く室外熱交換器内を流れる冷媒の蒸発温度が下がる。冷媒の蒸発温度が下がると室外熱交換器の外気側の表面温度も下がり、益々着霜を生じやすくなり、着霜が進行する。このままでは室外熱交換器で室外空気から汲み上げる熱量が減少するため室内熱交換器から放熱する熱量も減少するため暖房能力も減少し、室内の快適性が損なわれる。これを防ぐために室外熱交換器の着霜の量が所定の量を超えた時には除霜運転をすることにより室外熱交換器の着霜を融解し、流下させて機外に排出させる。   When the air heat source heat pump air conditioner is operated for heating, the outdoor heat exchanger forms frost if the humidity of the outdoor air is high. When frost formation occurs, the ventilation path of the outdoor heat exchanger is narrowed, so that the amount of outdoor air circulating through the outdoor heat exchanger is reduced. When the amount of circulating outdoor air decreases, the amount of heat exchange decreases, so that the evaporation temperature of the refrigerant flowing in the outdoor heat exchanger decreases to compensate for this. When the evaporation temperature of the refrigerant decreases, the surface temperature of the outdoor heat exchanger on the outside air side also decreases, and frost formation tends to occur more and more. If this is the case, the amount of heat pumped up from the outdoor air by the outdoor heat exchanger will decrease, so the amount of heat radiated from the indoor heat exchanger will also decrease, so the heating capacity will also decrease and indoor comfort will be impaired. In order to prevent this, when the amount of frost formation on the outdoor heat exchanger exceeds a predetermined amount, the frost formation on the outdoor heat exchanger is melted by flowing out the defrosting operation, and then is allowed to flow down and discharged outside the apparatus.

従来から広く知られている除霜方式として逆サイクル除霜方式がある。これは、暖房運転中に除霜が必要になった場合には、冷凍サイクルを冷房サイクルに切換えて、圧縮機、室内機を熱源とし、圧縮機からの高温ガス冷媒を室外熱交換器に流して除霜するものである。   There is a reverse cycle defrosting method as a widely known defrosting method. If defrosting is required during heating operation, the refrigeration cycle is switched to the cooling cycle, the compressor and the indoor unit are used as heat sources, and the high-temperature gas refrigerant from the compressor is allowed to flow to the outdoor heat exchanger. To defrost.

また、室内の暖房をしながら室外熱交換器の除霜を行う空気調和機として、特開平０９−３１８２０６号公報（特許文献１）、特開２００１−０５９６６４号公報（特許文献２）、特開２００２−１８８８７３号公報（特許文献３）、特開平０４−１１０５７６号公報（特許文献４）が知られている。   Moreover, as an air conditioner that performs defrosting of an outdoor heat exchanger while heating a room, JP 09-318206 A (Patent Document 1), JP 2001-059664 A (Patent Document 2), JP Japanese Patent Laid-Open No. 2002-188873 (Patent Document 3) and Japanese Patent Laid-Open No. 04-110576 (Patent Document 4) are known.

特許文献１には、暖房運転時には室外熱交換器が蒸発器となり、室内熱交換器が凝縮器となって室内を暖房するヒートポンプ式空気調和機において、室外熱交換器を上下方向に複数に分割し、分割された各室外熱交換器を室内熱交換器に並列に配管接続するとともに、それぞれ二方弁を介してコンプレッサの吸入口側に配管接続し、かつ、コンプレッサの吐出口側を分岐させて、各室外熱交換器にそれぞれ二方弁を介して配管接続し、暖房運転時に除霜を行うときは、コンプレッサからの吐出ガスの一部を分割された各室外熱交換器に上部側から下部側に順次切換えながら流して暖房と徐霜を並行して行うようにしたことが開示されている。   In Patent Document 1, in a heat pump air conditioner that heats a room by using an outdoor heat exchanger as an evaporator and an indoor heat exchanger as a condenser during heating operation, the outdoor heat exchanger is divided into a plurality of parts in the vertical direction. The divided outdoor heat exchangers are connected to the indoor heat exchanger in parallel, connected to the inlet side of the compressor via two-way valves, and the outlet side of the compressor is branched. When each pipe is connected to each outdoor heat exchanger via a two-way valve and defrosting is performed during heating operation, a part of the discharge gas from the compressor is divided into each divided outdoor heat exchanger from the upper side. It is disclosed that heating and gradual frosting are performed in parallel while sequentially switching to the lower side.

特許文献２には、圧縮機と、四方弁と、室内熱交換器と、膨張弁と、室外熱交換器とを冷媒配管によって連結し冷凍サイクルを構成してなる空気調和機において、室外熱交換器を室外送風機の回転に伴って発生する空気流に対し前後二列に分離し、それぞれに膨張弁を連結した並列構成にするとともに、圧縮機の吐出側配管と、両室外熱交換器の暖房時入口側配管との間に開閉弁を備えたバイパス路を設け、高能力暖房運転、低能力暖房運転、除霜と暖房の同時運転等を行うよう設定したことが開示されている。   Patent Document 2 discloses an outdoor heat exchange in an air conditioner in which a compressor, a four-way valve, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger are connected by a refrigerant pipe to form a refrigeration cycle. The compressor is separated into two rows before and after the air flow generated by the rotation of the outdoor blower and connected in parallel to each other, and the discharge side piping of the compressor and the heating of both outdoor heat exchangers It is disclosed that a bypass passage provided with an on-off valve is provided between the hour inlet side pipe and a high capacity heating operation, a low capacity heating operation, a simultaneous operation of defrosting and heating, and the like are performed.

特許文献３には、複数に分割された熱交換器を並列に接続してなる室外側熱交換器と、この室外側熱交換器に圧縮機、四方弁、室内側熱交換器、減圧装置を接続して構成される暖房運転可能な冷凍サイクルと、圧縮機から吐出した吐出ガスを前記室外側熱交換器の暖房運転時、入口となる各熱交換器の口部にそれぞれ導くためのバイパス路と、このバイパス路の各出口を開閉する開閉手段と、室外側熱交換器の各熱交換器に対する着霜を検知する検知手段と、暖房運転時、前記検知結果にしたがって開閉手段を制御し圧縮機からの吐出ガスを着霜した熱交換器へ流入させる手段とを具備したことが開示されている。   In Patent Document 3, an outdoor heat exchanger formed by connecting a plurality of divided heat exchangers in parallel, and a compressor, a four-way valve, an indoor heat exchanger, and a pressure reducing device are connected to the outdoor heat exchanger. A refrigeration cycle configured to be connected and capable of heating operation, and a bypass path for guiding the discharge gas discharged from the compressor to the mouth of each heat exchanger that serves as an inlet during the heating operation of the outdoor heat exchanger And opening / closing means for opening / closing each outlet of the bypass passage, detection means for detecting frost formation on each heat exchanger of the outdoor heat exchanger, and controlling and compressing the opening / closing means according to the detection result during heating operation And a means for causing the discharge gas from the machine to flow into a frosted heat exchanger.

特許文献４には、圧縮機と、流路切換用四方弁と、並列接続される２つの室外熱交換器と、冷暖切換可能な減圧装置と、室内熱交換器とを順次配管接続して冷凍サイクルを構成する空気調和機の冷凍装置において、２つの室外熱交換器とそれぞれ直列に冷暖兼用減圧器を配管接続すると共に、圧縮機の吐出側から開閉弁をそれぞれ備える２つのバイパス管を分岐し、同２つのバイパス管を室外熱交換器と冷暖兼用減圧器との間を配管接続する２つの接続配管にそれぞれ接続してなり、除霜運転時、各バイパス管に備える開閉弁を交互に開閉して、２つの室外熱交換器を交互に除霜するようにしたことが開示されている。   In Patent Document 4, a compressor, a four-way valve for switching a flow path, two outdoor heat exchangers connected in parallel, a pressure reducing device capable of switching between cooling and heating, and an indoor heat exchanger are sequentially piped and refrigerated. In an air conditioner refrigeration system that constitutes a cycle, a cooling / heating decompressor is connected in series with two outdoor heat exchangers, and two bypass pipes each provided with an on-off valve are branched from the discharge side of the compressor. The two bypass pipes are connected to two connection pipes that connect between the outdoor heat exchanger and the cooling / heating decompressor, and the open / close valves provided in each bypass pipe are alternately opened and closed during the defrosting operation. Then, it is disclosed that two outdoor heat exchangers are alternately defrosted.

特開平０９−３１８２０６号公報JP 09-318206 A 特開２００１−０５９６６４号公報JP 2001-059664 A 特開平０４−１１０５７６号公報Japanese Patent Laid-Open No. 04-110576 特開２００２−１８８８７３号公報JP 2002-188873 A

寒い朝などの低温時に暖房運転を開始する場合、室温が設定温度に到達する前に除霜を開始することが必要となり、前述の逆サイクル除霜方式の空気調和機では、暖房運転を止めて逆サイクル除霜運転を始めるため、除霜中に室温が大きく低下して快適性が損なわれると共に、室温が設定温度に到達するまでの時間が長くなる、という問題があった。   When heating operation is started at a low temperature such as in the cold morning, it is necessary to start defrosting before the room temperature reaches the set temperature. In the above-mentioned reverse cycle defrosting type air conditioner, heating operation is stopped. Since the reverse cycle defrosting operation is started, there is a problem that the room temperature greatly decreases during the defrosting and the comfort is impaired, and the time until the room temperature reaches the set temperature is increased.

特許文献１の空気調和機では、暖房運転中に常時除霜を行うようにしているので、暖房能力が常時低下した状態で室内の暖房を行うことになる、という問題があった。また、３分割された室外熱交換器の最小部分の除霜を順次切換えて行うようにしているので、除霜時間が長くなる、という問題があった。   In the air conditioner of Patent Document 1, since defrosting is always performed during heating operation, there is a problem that indoor heating is performed in a state where the heating capacity is constantly reduced. Moreover, since the defrosting of the minimum part of the outdoor heat exchanger divided into three is performed by sequentially switching, there is a problem that the defrosting time becomes long.

特許文献２及び特許文献３の空気調和機では、室外熱交換器を空気流に対し前後二列に分離して交互に除霜するようにしているので、分離された室外熱交換器における一方の除霜により生じた融解水を他方の霜の融解に利用できず、効率良く短時間で除霜することができない、という問題があった。   In the air conditioners of Patent Literature 2 and Patent Literature 3, since the outdoor heat exchanger is separated into two front and rear rows with respect to the air flow and alternately defrosted, one of the separated outdoor heat exchangers There was a problem that the melted water generated by defrosting could not be used for melting the other frost and could not be efficiently defrosted in a short time.

特許文献４の空気調和機では、室外熱交換器を空気流に対し左右に分離して交互に除霜するようにしているので、分離された室外熱交換器における一方の除霜により生じた融解水を他方の霜の融解に利用できず、効率良く短時間で除霜できない、という問題があった。   In the air conditioner of Patent Document 4, since the outdoor heat exchanger is separated into the left and right with respect to the air flow and alternately defrosted, melting caused by one defrosting in the separated outdoor heat exchanger There was a problem that water could not be used for melting the other frost and could not be efficiently defrosted in a short time.

本発明の目的は、除霜を暖房と同時に行って室内の快適性を確保しつつ、除霜時間を短縮できる空気調和機を提供することにある。   The objective of this invention is providing the air conditioner which can shorten a defrost time, performing a defrost simultaneously with heating and ensuring indoor comfort.

前述の目的を達成するために、本発明は、圧縮機、四方弁、室内熱交換器、減圧装置及び室外熱交換器を冷媒配管で連結して冷凍サイクルを構成し、前記室外熱交換器を２つに分けて並列に接続すると共に、前記２つに分けられた各室外熱交換器の冷媒回路の暖房運転時入口側に主回路開閉機構を設け、前記圧縮機の吐出側と前記２つに分けられた各室外熱交換器の冷媒回路の暖房運転時入口側とを連結するホットガスバイパス回路を設けると共に、ホットガスバイパス回路にバイパス開閉弁を設け、運転を制御する制御装置を備えた空気調和機において、前記室外熱交換器は、その冷媒回路を上下に２つに分けて、下側熱交換器とこの下側熱交換器より大きい上側熱交換器とを構成し、前記制御装置は、暖房運転中に除霜を開始する場合に、前記主回路開閉機構及び前記バイパス開閉弁を逆に開閉して、前記上側熱交換器を除霜しつつ前記下側熱交換器で暖房する除霜・暖房運転をした後に、前記下側熱交換器を除霜しつつ前記上側熱交換器で暖房する除霜・暖房運転をし、この除霜・暖房運転の終了後に暖房運転に復帰するように制御することにある。   In order to achieve the above object, the present invention comprises a compressor, a four-way valve, an indoor heat exchanger, a pressure reducing device, and an outdoor heat exchanger connected by a refrigerant pipe to form a refrigeration cycle, and the outdoor heat exchanger is The main circuit opening / closing mechanism is provided on the inlet side during heating operation of the refrigerant circuit of each of the two outdoor heat exchangers divided into two and connected in parallel, and the discharge side of the compressor and the two A hot gas bypass circuit that connects the inlet side of the refrigerant circuit of each outdoor heat exchanger divided into the heating operation is provided, and a bypass open / close valve is provided in the hot gas bypass circuit to control the operation. In the air conditioner, the outdoor heat exchanger divides the refrigerant circuit into two parts, and constitutes a lower heat exchanger and an upper heat exchanger larger than the lower heat exchanger, and the control device When starting defrosting during heating operation The lower side heat exchange is performed after defrosting / heating operation in which the main circuit opening / closing mechanism and the bypass opening / closing valve are opened / closed to heat the lower side heat exchanger while defrosting the upper side heat exchanger. The defrosting / heating operation is performed by heating the upper heat exchanger while defrosting the heater, and control is performed so as to return to the heating operation after the completion of the defrosting / heating operation.

係る本発明のより好ましい具体的な構成例は次の通りである。
（１）前記制御装置は、前記上側熱交換器を除霜しつつ前記下側熱交換器で暖房する除霜・暖房運転の時間よりも前記下側熱交換器を除霜しつつ前記上側熱交換器で暖房する除霜・暖房運転の時間を長くすること。
（２）鋼鉄製の外殻を持つ圧縮機を用い、外気温０℃以上のときの除霜禁止期間を次の式（１）の数値以下とすることを特徴とする空気調和機。 A more preferable specific configuration example of the present invention is as follows.
(1) The control device defrosts the lower heat exchanger while defrosting the upper heat exchanger while heating the lower heat exchanger while heating the lower heat exchanger while defrosting the upper heat exchanger. Prolong the time for defrosting and heating that is heated by the exchanger.
(2) An air conditioner using a compressor having a steel outer shell, wherein the defrosting prohibition period when the outside air temperature is 0 ° C. or higher is set to be equal to or less than the numerical value of the following equation (1).

除霜禁止期間（単位：分）＝８×圧縮機の質量（単位：ｋｇ）／室外熱交換器の吸熱量（単位：ｋＷ） … （１）。
（３）前記除霜禁止期間を２０分〜５分とすること。
（４）前記制御装置は、外気温の低下に基づいて、前記圧縮機の吐出温度を高温側にシフトして制御すると共に、除霜禁止期間を短縮するように制御すること。
（５）前記制御装置は、除霜・暖房運転時に暖房運転時よりも室外送風装置の回転数を低下させ、更に、外気温度が所定値より低い場合の除霜運転時に室外送風装置の運転を停止するように制御すること。
（６）前記制御装置は、除霜・暖房運転を除霜運転時間に達するまで行っても前記室外熱交換器の温度が所定値に達しない場合に前記四方弁を切換えて逆サイクル除霜運転を行うように制御すること。 Defrosting prohibition period (unit: minute) = 8 × mass of compressor (unit: kg) / heat absorption amount of outdoor heat exchanger (unit: kW) (1).
(3) The said defrost prohibition period shall be 20 minutes-5 minutes.
(4) The control device controls the discharge temperature of the compressor by shifting to a high temperature side based on a decrease in outside air temperature, and controls the defrosting prohibition period to be shortened.
(5) The control device lowers the rotational speed of the outdoor air blower during the defrosting / heating operation than during the heating operation, and further operates the outdoor air blower during the defrosting operation when the outside air temperature is lower than a predetermined value. Control to stop.
(6) If the temperature of the outdoor heat exchanger does not reach a predetermined value even if the defrosting / heating operation is performed until the defrosting operation time is reached, the control device switches the four-way valve to perform the reverse cycle defrosting operation. Control to do.

係る本発明の空気調和機によれば、除霜を暖房と同時に行って室内の快適性を確保しつつ、除霜時間を短縮できる。   According to the air conditioner of the present invention, the defrosting time can be shortened while defrosting is performed simultaneously with heating to ensure indoor comfort.

以下、本発明の一実施例に係る空気調和機について図を用いて説明する。   Hereinafter, an air conditioner according to an embodiment of the present invention will be described with reference to the drawings.

まず、本実施例の空気調和機の全体構成に関して図１及び図２を用いて説明する。図１は本発明の一実施例の空気調和機の構成図である。図２は図１の空気調和機の冷凍サイクル構成図である。   First, the whole structure of the air conditioner of a present Example is demonstrated using FIG.1 and FIG.2. FIG. 1 is a configuration diagram of an air conditioner according to an embodiment of the present invention. FIG. 2 is a configuration diagram of the refrigeration cycle of the air conditioner of FIG.

空気調和機１は、冷凍サイクルと、送風装置と、これらを制御する制御系とを備えて構成されている。なお、この空気調和機１は、室内機２と室外機６とを冷媒配管８、電気配線、信号配線などを介して接続されたセパレート形空気調和機である。   The air conditioner 1 includes a refrigeration cycle, a blower, and a control system that controls them. The air conditioner 1 is a separate air conditioner in which an indoor unit 2 and an outdoor unit 6 are connected via a refrigerant pipe 8, electrical wiring, signal wiring, and the like.

冷凍サイクルは、圧縮機７５、四方弁７２、室外熱交換器７３、主回路開閉弁７１３ａ、７１３ｂ、減圧装置７４、ホットパイプ７１３ｄ、室内熱交換器３３、バイパス開閉弁７１５ａ、７１５ｂを備え、これらを冷媒配管を介して接続することにより構成されている。冷媒配管は、吸込配管７１０、吐出配管７１１、利用側ガス管７１２、液管７１３、熱源側ガス管７１４、ホットガスバイパス管７１５、ホットパイプ７１３ｄ、上側バイパス管７１６ａ、下側バイパス管７１６ｂなどで構成されている。   The refrigeration cycle includes a compressor 75, a four-way valve 72, an outdoor heat exchanger 73, main circuit on / off valves 713a and 713b, a pressure reducing device 74, a hot pipe 713d, an indoor heat exchanger 33, and bypass on / off valves 715a and 715b. Are connected through a refrigerant pipe. The refrigerant pipe is a suction pipe 710, a discharge pipe 711, a use side gas pipe 712, a liquid pipe 713, a heat source side gas pipe 714, a hot gas bypass pipe 715, a hot pipe 713d, an upper bypass pipe 716a, a lower bypass pipe 716b, and the like. It is configured.

室内熱交換器３３は室内機２に収納され、圧縮機７５、四方弁７２、室外熱交換器７３、主回路開閉弁７１３ａ、７１３ｂ、減圧装置７４、ホットパイプ７１３ｄ、バイパス開閉弁７１５ａ、７１５ｂは室外機６に収納されている。   The indoor heat exchanger 33 is housed in the indoor unit 2, and the compressor 75, the four-way valve 72, the outdoor heat exchanger 73, the main circuit on / off valves 713a and 713b, the pressure reducing device 74, the hot pipe 713d, and the bypass on / off valves 715a and 715b It is stored in the outdoor unit 6.

四方弁７２は冷媒流路切換弁の一例である。この四方弁７２は、冷房サイクルと暖房サイクルとを切換えるものである。ここで、冷房サイクルは、圧縮機７５から吐出配管７１１を介して吐出された冷媒を室外熱交換器７３へ導き、室内熱交換器３３からの冷媒を圧縮機７５に戻すサイクルである。暖房サイクルは、圧縮機７５から吐出された冷媒を室内熱交換器３３へ導き、室外熱交換器７３からの冷媒を吸込配管７１０及びアキュムレータ７６を介して圧縮機７５に戻すサイクルである。   The four-way valve 72 is an example of a refrigerant flow path switching valve. The four-way valve 72 switches between a cooling cycle and a heating cycle. Here, the cooling cycle is a cycle in which the refrigerant discharged from the compressor 75 via the discharge pipe 711 is guided to the outdoor heat exchanger 73 and the refrigerant from the indoor heat exchanger 33 is returned to the compressor 75. The heating cycle is a cycle in which the refrigerant discharged from the compressor 75 is guided to the indoor heat exchanger 33 and the refrigerant from the outdoor heat exchanger 73 is returned to the compressor 75 via the suction pipe 710 and the accumulator 76.

従って、室外熱交換器７３は、冷房サイクルの冷房運転時に高圧側熱交換器（凝縮器）を構成し、暖房サイクルの暖房運転時に低圧側熱交換器（蒸発器）を構成する。また、室内熱交換器３３は、暖房サイクルの暖房運転時に高圧側熱交換器（凝縮器）を構成し、冷房サイクルの冷房運転時に低圧側熱交換器（蒸発器）を構成する。   Accordingly, the outdoor heat exchanger 73 constitutes a high-pressure side heat exchanger (condenser) during the cooling operation of the cooling cycle, and constitutes a low-pressure side heat exchanger (evaporator) during the heating operation of the heating cycle. The indoor heat exchanger 33 constitutes a high-pressure side heat exchanger (condenser) during the heating operation of the heating cycle, and constitutes a low-pressure side heat exchanger (evaporator) during the cooling operation of the cooling cycle.

室外熱交換器７３は、冷媒配管と熱交換フィンとで構成され、その冷媒配管で形成される冷媒回路を複数に分割して並列に接続されている。この冷媒回路は上側の冷媒回路と下側冷媒回路との２つの冷媒回路に区分して構成されている。室外熱交換器７３は、上側の冷媒回路を含む上側熱交換器７３１と、下側の冷媒回路を含む下側熱交換器７３２とからなっている。上側熱交換器７３１は、第１上側冷媒回路７３１ａ、第２上側冷媒回路７３１ｂ、第３上側冷媒回路７３１ｃを有している。下側熱交換器７３２は、第１下側冷媒回路７３２ａ、第２下側冷媒回路７３２ｂを有している。   The outdoor heat exchanger 73 includes a refrigerant pipe and heat exchange fins, and a refrigerant circuit formed by the refrigerant pipe is divided into a plurality of pieces and connected in parallel. This refrigerant circuit is divided into two refrigerant circuits, an upper refrigerant circuit and a lower refrigerant circuit. The outdoor heat exchanger 73 includes an upper heat exchanger 731 including an upper refrigerant circuit and a lower heat exchanger 732 including a lower refrigerant circuit. The upper heat exchanger 731 includes a first upper refrigerant circuit 731a, a second upper refrigerant circuit 731b, and a third upper refrigerant circuit 731c. The lower heat exchanger 732 includes a first lower refrigerant circuit 732a and a second lower refrigerant circuit 732b.

上側熱交換器７３１及び下側熱交換器７３２の各々は、主回路開閉弁７１３ａ、７１３ｂを介して、減圧装置７４に接続されている。また、上側熱交換器７３１、下側熱交換器７３２と主回路開閉弁７１３ａ、７１３ｂとの間から分岐し、バイパス開閉弁７１５ａ、７１５ｂを介して圧縮機７５の吐出管７１１にホットガスバイパス管７１５で接続されるホットガスバイパス回路が設けられている。   Each of the upper heat exchanger 731 and the lower heat exchanger 732 is connected to the decompression device 74 via main circuit on-off valves 713a and 713b. Moreover, it branches from between the upper side heat exchanger 731 and the lower side heat exchanger 732, and main circuit on-off valve 713a, 713b, and it is a hot gas bypass pipe to the discharge pipe 711 of the compressor 75 via bypass on-off valve 715a, 715b. A hot gas bypass circuit connected at 715 is provided.

減圧装置７４は、室外熱交換器７３と室内熱交換器３３との間に設けられ、冷房サイクルの冷房時に室外熱交換器７３からの冷媒を減圧し、暖房サイクルの暖房運転時に室内熱交換器３３からの冷媒を減圧する。なお、本実施例では減圧装置７４は絞り開度が制御可能な膨張弁、例えば電動式などで構成されている。   The decompression device 74 is provided between the outdoor heat exchanger 73 and the indoor heat exchanger 33, depressurizes the refrigerant from the outdoor heat exchanger 73 during cooling of the cooling cycle, and the indoor heat exchanger during heating operation of the heating cycle. The refrigerant from 33 is depressurized. In the present embodiment, the decompression device 74 is configured by an expansion valve whose throttle opening can be controlled, for example, an electric type.

主回路開閉弁７１３ａ、７１３ｂ及びバイパス開閉弁７１５ａ、７１５ｂは、電磁式開閉弁で構成され、冷媒の主回路及びホットガスバイパス回路を開閉するものである。   The main circuit on / off valves 713a and 713b and the bypass on / off valves 715a and 715b are composed of electromagnetic on / off valves, and open and close the refrigerant main circuit and the hot gas bypass circuit.

空気調和機１における送風装置は、室外機６に収納された室外送風装置６３と、室内機２に収納された室内送風装置３１とからなっている。室外送風装置は、室外熱交換器７３に室外空気を流通させる室外ファン６３１と、室外ファン６３１を駆動する室外送風モーター６３３とを備えている。室内送風装置は、室内熱交換器３３に室内の空気を流通させる室内ファン３１１と、室内ファン３１１を駆動する室内送風モーター３１３とを備えている。本実施例では、室外ファン６３１として軸流ファンを使用し、室内ファン３１１として横流ファンを使用している。   The air blower in the air conditioner 1 includes an outdoor air blower 63 accommodated in the outdoor unit 6 and an indoor air blower 31 accommodated in the indoor unit 2. The outdoor blower includes an outdoor fan 631 that causes outdoor air to flow through the outdoor heat exchanger 73 and an outdoor blower motor 633 that drives the outdoor fan 631. The indoor air blower includes an indoor fan 311 that allows indoor air to flow through the indoor heat exchanger 33 and an indoor air blower motor 313 that drives the indoor fan 311. In this embodiment, an axial fan is used as the outdoor fan 631 and a cross fan is used as the indoor fan 311.

空気調和機１における制御系は、冷媒温検知センサー８１１ａ、８１１ｂ、８１２と、制御装置１０とを備えて構成されている。冷媒温検知センサー８１１ａ、８１１ｂ、８１２は、暖房時の室外熱交換器７３の上側熱交換器７３１、下側熱交換器７３２の出口温度を検出する冷媒温検知センサー８１１ａ、８１１ｂと、逆サイクル除霜時の室外熱交換器７３の出口温度を検出する冷媒温検知センサー８１２とから構成されている。   The control system in the air conditioner 1 includes refrigerant temperature detection sensors 811a, 811b, and 812 and a control device 10. The refrigerant temperature detection sensors 811a, 811b, and 812 include refrigerant temperature detection sensors 811a and 811b that detect the outlet temperatures of the upper heat exchanger 731 and the lower heat exchanger 732 of the outdoor heat exchanger 73 during heating, and reverse cycle removal. It is comprised from the refrigerant | coolant temperature detection sensor 812 which detects the exit temperature of the outdoor heat exchanger 73 at the time of frost.

制御装置１０は、冷媒温検知センサー８１１ａ、８１１ｂ、８１２の検出結果や使用者の運転指令に基づいて、圧縮機７５、四方弁７２、室外送風モーター６３３、室内送風モーター３１３、減圧装置７４、主回路開閉弁７１３ａ、７１３ｂ、バイパス開閉弁７１５ａ、７１５ｂなどを制御する。なお、本実施例では、制御装置１０は、演算する機能を有する制御装置と、各機器を制御する機能を有する制御装置とを一つで示してあるが、これらが分けて構成されていても良く、或いは各機器を制御する機能を有する制御装置がさらに分けて構成されていても良い。   Based on the detection results of the refrigerant temperature detection sensors 811a, 811b, and 812 and the user's operation command, the control device 10 includes a compressor 75, a four-way valve 72, an outdoor fan motor 633, an indoor fan motor 313, a decompressor 74, The circuit open / close valves 713a and 713b, the bypass open / close valves 715a and 715b, and the like are controlled. In the present embodiment, the control device 10 is shown as a single control device having a function of calculating and a control device having a function of controlling each device. However, the control device 10 may be configured separately. Alternatively, a control device having a function of controlling each device may be further divided.

次に、空気調和機１の運転動作を図３〜図８を参照しながら説明する。   Next, the operation of the air conditioner 1 will be described with reference to FIGS.

先ず、冷房サイクルにおける冷房運転について図４を用いて説明する。図４は図１の空気調和機の冷房運転時の冷媒の流れを示す冷凍サイクル図である。空気調和機１の冷房運転をする際には、四方弁７２を図４のように切換え、主回路開閉弁７１３ａ、７１３ｂを開、バイパス開閉弁７１５ａ、７１５ｂを閉にして冷房運転サイクルを形成すると共に、圧縮機７５、室外送風モーター６３３及び室内送風モーター３１３を運転する。   First, the cooling operation in the cooling cycle will be described with reference to FIG. FIG. 4 is a refrigeration cycle diagram showing the refrigerant flow during the cooling operation of the air conditioner of FIG. When the air conditioner 1 is in cooling operation, the four-way valve 72 is switched as shown in FIG. 4, the main circuit on / off valves 713a and 713b are opened, and the bypass on / off valves 715a and 715b are closed to form a cooling operation cycle. At the same time, the compressor 75, the outdoor fan motor 633, and the indoor fan motor 313 are operated.

圧縮機７５に吸込まれたガス冷媒は、圧縮機７５で圧縮され、高温高圧のガス冷媒となって、図４の実線矢印の方向に流れ、四方弁７２を通って凝縮器となる室外熱交換器７３の上側熱交換器７３１及び下側熱交換器７３２に入り、室外空気と熱交換し冷却されて凝縮され、液または気液混合の冷媒となる。   The gas refrigerant sucked into the compressor 75 is compressed by the compressor 75, becomes a high-temperature and high-pressure gas refrigerant, flows in the direction of the solid line arrow in FIG. It enters the upper heat exchanger 731 and the lower heat exchanger 732 of the heat exchanger 73, exchanges heat with outdoor air, is cooled and condensed, and becomes a refrigerant of liquid or gas-liquid mixture.

次いで、冷媒は、主回路開閉弁７１３ａ、７１３ｂを介して、減圧装置７４に入り、膨張して減圧され、低圧の気液混合の冷媒となる。この気液混合冷媒は、図４で低圧冷媒の流れを示す破線の矢印の方向に流れ、ホットパイプ７１３ｄを通った後、室外機６を出て室内機２に入り、蒸発器となる室内熱交換器３３に入り、室内空気と熱交換して室内を冷房し、自身は加熱され、ガス冷媒となって圧縮機７５に戻る。   Next, the refrigerant enters the decompression device 74 via the main circuit on-off valves 713a and 713b, expands and is decompressed, and becomes a low-pressure gas-liquid mixed refrigerant. This gas-liquid mixed refrigerant flows in the direction of the dashed arrow indicating the flow of the low-pressure refrigerant in FIG. 4, passes through the hot pipe 713 d, exits the outdoor unit 6, enters the indoor unit 2, and becomes the indoor heat serving as an evaporator It enters the exchanger 33 and exchanges heat with room air to cool the room. It is heated and returns to the compressor 75 as a gas refrigerant.

次に、暖房サイクルにおける暖房運転について図５を用いて説明する。図５は図１の空気調和機の暖房運転時の冷媒の流れを示す冷凍サイクル図である。暖房運転する際には、四方弁７２を図５のように切換え、主回路開閉弁７１３ａ、７１３ｂを開、バイパス開閉弁７１５ａ、７１５ｂを閉にして暖房運転サイクルを形成すると共に、圧縮機７５、室外送風モーター６３３及び室内送風モーター３１３を運転する。   Next, the heating operation in the heating cycle will be described with reference to FIG. FIG. 5 is a refrigeration cycle diagram showing the refrigerant flow during the heating operation of the air conditioner of FIG. When the heating operation is performed, the four-way valve 72 is switched as shown in FIG. 5, the main circuit on-off valves 713a and 713b are opened, the bypass on-off valves 715a and 715b are closed to form a heating operation cycle, and the compressor 75, The outdoor fan motor 633 and the indoor fan motor 313 are operated.

圧縮機７５に吸込まれたガス冷媒は、圧縮機７５で圧縮され、高温高圧のガス冷媒となって、図５の実線矢印の方向に流れ、四方弁７２を通って凝縮器となる室内熱交換器３３に入り、室内空気と熱交換し冷却されて凝縮され、液または気液混合の冷媒となる。   The gas refrigerant sucked into the compressor 75 is compressed by the compressor 75, becomes a high-temperature and high-pressure gas refrigerant, flows in the direction of the solid line arrow in FIG. It enters into the vessel 33, exchanges heat with room air, is cooled and condensed, and becomes a refrigerant of liquid or gas-liquid mixture.

凝縮して液または気液混合の冷媒となった冷媒は、室内機２を出て室外機６に入り、室外熱交換器７３の下部又は除霜水排出口近辺に引回されたホットパイプ７１３ｄを流れ、除霜時に落下した氷片を融解して室外機６の外に完全に排出し、室外機６内に残霜が生じないようにしている。ホットパイプ７１３ｄを通った冷媒は、減圧装置７４に入り、膨張して減圧され、低圧の気液混合の冷媒となる。この気液混合冷媒は、図５で低圧冷媒の流れを示す破線の矢印の方向に流れ、主回路開閉弁７１３ａ、７１３ｂを介して、蒸発器となる室外熱交換器７３の上側熱交換器７３１及び下側熱交換器７３２に入り、室外空気と熱交換して加熱され、ガス冷媒となって圧縮機７５に戻る。   The refrigerant that has condensed to become a liquid or gas-liquid mixed refrigerant exits the indoor unit 2 and enters the outdoor unit 6, and is hot pipe 713 d routed near the lower portion of the outdoor heat exchanger 73 or near the defrost water discharge port. The ice pieces dropped during defrosting are melted and completely discharged out of the outdoor unit 6 so that no residual frost is generated in the outdoor unit 6. The refrigerant passing through the hot pipe 713d enters the decompression device 74, expands and decompresses, and becomes a low-pressure gas-liquid mixed refrigerant. This gas-liquid mixed refrigerant flows in the direction of the broken-line arrow indicating the flow of the low-pressure refrigerant in FIG. 5, and the upper heat exchanger 731 of the outdoor heat exchanger 73 serving as an evaporator via the main circuit on-off valves 713a and 713b. And enters the lower heat exchanger 732, exchanges heat with the outdoor air and is heated to return to the compressor 75 as a gas refrigerant.

上述した暖房サイクルにおける暖房運転動作を繰り返すことにより、暖房運転が継続される。   By repeating the heating operation in the heating cycle described above, the heating operation is continued.

係る暖房運転時には、室外熱交換器７３は室外空気から熱を奪うため低温になり、０℃以下となって伝熱面に着霜することがある。外気の温度が低く、湿気が高いとこの現象は顕著になり、室外空気の流通面に付着した霜により、室外空気の流通が妨げられて室外ファン６３１の風量が減少する。室外ファン６３１の風量が減少するとこれを補うかのごとく室外熱交換器７３の温度が更に低下し、益々霜が着きやすくなる。かくして、室外熱交換器７３の着霜は増え続け、空気調和機１が室外空気から汲み上げる熱量が減少し、暖房能力も減少して、室内を十分に暖房できなくなり、暖房の機能が喪失してしまうので、除霜運転が必要になる。   During the heating operation, the outdoor heat exchanger 73 takes a heat from the outdoor air, and thus becomes a low temperature. This phenomenon becomes remarkable when the temperature of the outside air is low and the humidity is high, and the flow of the outdoor air 631 is reduced due to the frost adhering to the outdoor air flow surface, thereby preventing the outdoor air flow. When the air volume of the outdoor fan 631 is reduced, the temperature of the outdoor heat exchanger 73 is further lowered as if to compensate for this, and frost is more likely to be formed. Thus, the frost formation of the outdoor heat exchanger 73 continues to increase, the amount of heat pumped from the outdoor air by the air conditioner 1 decreases, the heating capacity also decreases, the room cannot be heated sufficiently, and the heating function is lost. Therefore, defrosting operation is necessary.

次に、暖房サイクルにおける除霜・暖房運転について図６及び図７を用いて説明する。図６は図１の空気調和機の室外熱交換器の上部を除霜する時の冷媒の流れを示す冷凍サイクル図、図７は図１の空気調和機の室外熱交換器の下部を除霜する時の冷媒の流れを示す冷凍サイクル図である。   Next, defrosting / heating operation in the heating cycle will be described with reference to FIGS. 6 and 7. 6 is a refrigeration cycle diagram showing the flow of refrigerant when defrosting the upper part of the outdoor heat exchanger of the air conditioner of FIG. 1, and FIG. 7 is defrosting the lower part of the outdoor heat exchanger of the air conditioner of FIG. It is a refrigerating cycle figure which shows the flow of the refrigerant | coolant at the time of doing.

前述のように、暖房運転をしていると、湿気の多い日には、室外熱交換器７３に霜が付き、暖房能力が落ちてくる。冷媒温検知センサー８１２が所定の温度を下回り、かつ、暖房サイクルでの暖房運転を所定の時間以上行っている場合に、着霜の量が所定の量に達したとみなし、暖房サイクルによる除霜運転を行う。この除霜運転は、四方弁７２を図６のように暖房運転時と同じにし、主回路開閉弁７１３ａを閉、主回路開閉弁７１３ｂを開、バイパス開閉弁７１５ａを開、バイパス開閉弁７１５ｂを閉にして、室外熱交換器７３の内の上側熱交換器７３１を凝縮器として機能させると共に、下側熱交換器７３２を蒸発器として機能させ、除霜と暖房とを同時に行う除霜・暖房運転サイクルを形成する。この時、室外送風モーター６３３を低速運転し、室内送風モーター３１３は、吹出し温度が所定温度以上を保持できるように運転を制御する。   As described above, when heating operation is performed, frost is formed on the outdoor heat exchanger 73 on a humid day, and the heating capacity is reduced. When the refrigerant temperature detection sensor 812 is below a predetermined temperature and the heating operation in the heating cycle is performed for a predetermined time or more, it is considered that the amount of frost formation has reached the predetermined amount, and defrosting by the heating cycle is performed. Do the driving. In this defrosting operation, the four-way valve 72 is made the same as in the heating operation as shown in FIG. 6, the main circuit on-off valve 713a is closed, the main circuit on-off valve 713b is opened, the bypass on-off valve 715a is opened, and the bypass on-off valve 715b is opened. Defrosting and heating are performed by simultaneously closing the upper heat exchanger 731 in the outdoor heat exchanger 73 as a condenser and causing the lower heat exchanger 732 as an evaporator to perform defrosting and heating at the same time. Form an operating cycle. At this time, the outdoor air blowing motor 633 is operated at a low speed, and the indoor air blowing motor 313 controls the operation so that the blowing temperature can be maintained at a predetermined temperature or higher.

ここで、圧縮機７５に吸込まれたガス冷媒は、圧縮機７５で圧縮され、高温高圧のガス冷媒となって、吐出管７１１に吐出され、途中で分岐して、一方の冷媒は四方弁７２に入り、他方の冷媒はホットガスバイパス管７１５に入る。   Here, the gas refrigerant sucked into the compressor 75 is compressed by the compressor 75, becomes a high-temperature and high-pressure gas refrigerant, is discharged to the discharge pipe 711, branches in the middle, and one refrigerant is the four-way valve 72. And the other refrigerant enters the hot gas bypass pipe 715.

四方弁７２に入った一方の冷媒は、図６の実線矢印の方向に流れ、室内熱交換器３３に入り、室内空気と熱交換し冷却されて凝縮され、液または気液混合の冷媒となる。この際に室内の暖房が行われる。液または気液混合の冷媒となった冷媒は、室内機２を出て室外機６に入り、ホットパイプ７１３ｄを流れ、周辺の氷片を融解して室外機６の外に排出する。ホットパイプ７１３ｄを通った冷媒は、減圧装置７４に入り、膨張して減圧され、低圧の気液混合の冷媒となる。この気液混合冷媒は、図６で低圧冷媒の流れを示す破線の矢印の方向に流れ、主回路開閉弁７１３ｂを介して、蒸発器となる室外熱交換器７３の下側熱交換器７３２に入り、室外空気と熱交換して加熱され、ガス冷媒となって圧縮機７５に戻る。   One refrigerant that has entered the four-way valve 72 flows in the direction of the solid arrow in FIG. 6, enters the indoor heat exchanger 33, exchanges heat with indoor air, is cooled and condensed, and becomes a refrigerant of liquid or gas-liquid mixture. . At this time, the room is heated. The refrigerant that has become the liquid or gas-liquid mixed refrigerant exits the indoor unit 2 and enters the outdoor unit 6, flows through the hot pipe 713 d, melts the surrounding ice pieces, and discharges it to the outside of the outdoor unit 6. The refrigerant passing through the hot pipe 713d enters the decompression device 74, expands and decompresses, and becomes a low-pressure gas-liquid mixed refrigerant. This gas-liquid mixed refrigerant flows in the direction of the broken-line arrow indicating the flow of the low-pressure refrigerant in FIG. 6, and enters the lower heat exchanger 732 in the outdoor heat exchanger 73 serving as an evaporator via the main circuit on-off valve 713b. It enters, heat-exchanges with outdoor air, is heated, becomes a gas refrigerant, and returns to the compressor 75.

他方、ホットガスバイパス管７１５に入った冷媒は、図６の実線矢印の方向に流れ、バイパス開閉弁７１５ａを介して室外熱交換器７３の上側熱交換器７３１に入る。上側熱交換器７３１に入った冷媒は、高温高圧であるので上側熱交換器７３１に付着した霜を融解して下方に流下させる。流下した融解水は、蒸発器として作用している下側熱交換器７３２に流れ込み、最初は下側熱交換器７３２の着霜を融かしながら流下し、流下するに従って低温になり、外気温が低い場合などは終りには再氷結する。   On the other hand, the refrigerant that has entered the hot gas bypass pipe 715 flows in the direction of the solid line arrow in FIG. 6, and enters the upper heat exchanger 731 of the outdoor heat exchanger 73 via the bypass on-off valve 715a. Since the refrigerant that has entered the upper heat exchanger 731 has a high temperature and a high pressure, the frost adhering to the upper heat exchanger 731 is melted and flows downward. The molten water that has flowed down flows into the lower heat exchanger 732 acting as an evaporator, and flows down while melting the frost of the lower heat exchanger 732, and becomes lower temperature as it flows down. If it is low, it will freeze again at the end.

この時、融解水は下側熱交換器７３２に熱を与えながら流下し、その熱は下側熱交換器７３２内部の冷媒の気化を促進する。つまり、上側熱交換器７３１で着霜の融解に使われた熱の一部が下側熱交換器７３２の着霜を一部融解し、更に内部の冷媒の気化に寄与して回収され、除霜の熱量が有効に使われる。   At this time, the molten water flows down while applying heat to the lower heat exchanger 732, and the heat promotes vaporization of the refrigerant in the lower heat exchanger 732. That is, a part of the heat used for melting frost in the upper heat exchanger 731 partially melts the frost in the lower heat exchanger 732 and is further collected and contributed to vaporization of the internal refrigerant. The amount of frost heat is used effectively.

上側熱交換器７３１の霜を除霜した冷媒は上側熱交換器７３１を出たところで下側熱交換器７３２で気化した冷媒と合流し圧縮機７５に戻る。上側熱交換器７３１の除霜運転を所定時間または上側熱交換器７３１の出口の冷媒温検知センサー８１１ａが所定温度まで上昇すると、下側熱交換器７３２の除霜を次に行う。   The refrigerant from which the frost in the upper heat exchanger 731 has been defrosted joins the refrigerant vaporized in the lower heat exchanger 732 when it leaves the upper heat exchanger 731 and returns to the compressor 75. When the defrosting operation of the upper heat exchanger 731 is performed for a predetermined time or when the refrigerant temperature detection sensor 811a at the outlet of the upper heat exchanger 731 rises to a predetermined temperature, the lower heat exchanger 732 is defrosted next.

下側熱交換器７３２の除霜に切換えるには、主回路開閉弁７１３ａを開、主回路開閉弁７１３ｂを閉、バイパス開閉弁７１５ａを閉、バイパス開閉弁７１５ｂを開にして、室外熱交換器７３の内の下側熱交換器７３２を凝縮器として機能させると共に、上側熱交換器７３１を蒸発器として機能させ、除霜と暖房とを同時に行う除霜・暖房運転サイクルを形成する。この時、室外送風モーター６３３を低速運転し、室内送風モーター３１３は、吹出し温度が所定温度以上を保持できるように運転を制御する。   In order to switch to defrosting of the lower heat exchanger 732, the main circuit on-off valve 713a is opened, the main circuit on-off valve 713b is closed, the bypass on-off valve 715a is closed, and the bypass on-off valve 715b is opened. The lower heat exchanger 732 of 73 is functioned as a condenser and the upper heat exchanger 731 is functioned as an evaporator to form a defrosting / heating operation cycle in which defrosting and heating are performed simultaneously. At this time, the outdoor air blowing motor 633 is operated at a low speed, and the indoor air blowing motor 313 controls the operation so that the blowing temperature can be maintained at a predetermined temperature or higher.

ここで、四方弁７２から室内熱交換器３３に流れ、減圧装置７４で減圧されるまでの冷媒の流れは、上側熱交換器７３１を除霜する時と同じである。減圧装置７４で減圧された冷媒は、図７の破線の矢印の方向に流れ、主回路開閉弁７１３ａを介して、蒸発器となる上側熱交換器７３１に入り、室外空気と熱交換して加熱され、ガス冷媒となって圧縮機７５に戻る。   Here, the flow of the refrigerant from the four-way valve 72 to the indoor heat exchanger 33 and decompressed by the decompression device 74 is the same as when the upper heat exchanger 731 is defrosted. The refrigerant decompressed by the decompression device 74 flows in the direction of the broken arrow in FIG. 7, enters the upper heat exchanger 731 serving as an evaporator via the main circuit on-off valve 713a, and heats it by exchanging heat with outdoor air. Then, the gas refrigerant is returned to the compressor 75.

ホットガスバイパス管７１５に入った冷媒は、図７の実線矢印の方向に流れ、バイパス開閉弁７１５ｂを介して室外熱交換器７３の下側熱交換器７３２に入る。下側熱交換器７３２に入った冷媒は、高温高圧であるので、下側熱交換器７３２に付着した霜を融解して下方に流下させる。流下した融解水は、除霜水の排出口から室外機６の外に排出される。下側熱交換器７３２の霜を除霜した冷媒は、下側熱交換器７３２を出たところで上側熱交換器７３１で気化した冷媒と合流し圧縮機７５に戻る。下側熱交換器７３２の除霜運転が所定時間経過すると、または下側熱交換器７３２の出口の冷媒温検知センサー８１１ｂが所定温度まで上昇すると、主回路開閉弁７１３ａ、７１３ｂを開、バイパス開閉弁７１５ａ、７１５ｂを閉にして、除霜・暖房運転を終了し、直ちに図５の暖房運転に復帰する。   The refrigerant that has entered the hot gas bypass pipe 715 flows in the direction of the solid line arrow in FIG. 7 and enters the lower heat exchanger 732 of the outdoor heat exchanger 73 via the bypass on-off valve 715b. Since the refrigerant that has entered the lower heat exchanger 732 has a high temperature and pressure, the frost adhering to the lower heat exchanger 732 is melted and allowed to flow downward. The molten water that has flowed down is discharged out of the outdoor unit 6 through the discharge port of the defrost water. The refrigerant that has defrosted the frost in the lower heat exchanger 732 joins the refrigerant vaporized in the upper heat exchanger 731 when it leaves the lower heat exchanger 732, and returns to the compressor 75. When the defrosting operation of the lower heat exchanger 732 elapses for a predetermined time or when the refrigerant temperature detection sensor 811b at the outlet of the lower heat exchanger 732 rises to a predetermined temperature, the main circuit on-off valves 713a and 713b are opened, and the bypass opening / closing The valves 715a and 715b are closed, the defrosting / heating operation is finished, and the operation immediately returns to the heating operation of FIG.

上述したように、空気熱源ヒートポンプ空気調和機を暖房運転した場合、室外空気の湿度が高いと、室外熱交換器７３に着霜を生ずる。着霜が生ずると室外熱交換器７３の通風路が狭まるため、室外熱交換器７３を循環する室外空気の量が減少する。循環する室外空気の量が減少すると、熱交換量が少なくなるため、これを補おうとする如く室外熱交換器７３内を流れる冷媒の蒸発温度が下がる。冷媒の蒸発温度が下がると室外熱交換器７３の外気側の表面温度も下がり、益々着霜を生じやすくなり、着霜が進行する。   As described above, when the air heat source heat pump air conditioner is operated for heating, frost is generated in the outdoor heat exchanger 73 if the humidity of the outdoor air is high. When frost formation occurs, the ventilation path of the outdoor heat exchanger 73 is narrowed, so that the amount of outdoor air circulating through the outdoor heat exchanger 73 is reduced. When the amount of circulating outdoor air decreases, the amount of heat exchange decreases, so that the evaporation temperature of the refrigerant flowing in the outdoor heat exchanger 73 decreases to compensate for this. When the evaporation temperature of the refrigerant decreases, the surface temperature of the outdoor heat exchanger 73 on the outside air side also decreases, and frost formation is more likely to occur, and frost formation proceeds.

このままでは室外熱交換器７３で室外空気から汲み上げる熱量が減少するため、室内熱交換器３３から放熱する熱量も減少して暖房能力が減少し、室内の快適性が損なわれる。これを防ぐために、室外熱交換器７３の着霜の量が所定の量を超えた時には除霜をすることにより、室外熱交換器７３の着霜を融解して流下させて機外に排出させる。この時、室外熱交換器７３の下部は上部から流れてきた融解水が通過するため、上部より水滴が残り易い。水滴が残った状態で除霜運転が終了して暖房運転が始まると、残った水滴が氷結して室外空気の通風を妨害する。室外空気の通風が妨害されると、前述のように着霜が成長し易くなり、暖房能力の低下が進行する。   In this state, the amount of heat pumped up from the outdoor air by the outdoor heat exchanger 73 decreases, so the amount of heat radiated from the indoor heat exchanger 33 also decreases, the heating capacity decreases, and indoor comfort is impaired. In order to prevent this, when the amount of frost formation in the outdoor heat exchanger 73 exceeds a predetermined amount, the frost formation in the outdoor heat exchanger 73 is melted down and discharged outside the apparatus by defrosting. . At this time, the molten water flowing from the upper part passes through the lower part of the outdoor heat exchanger 73, so that water droplets are likely to remain from the upper part. When the defrosting operation is finished and the heating operation is started with water droplets remaining, the remaining water droplets freeze and obstruct outdoor air flow. When the ventilation of the outdoor air is obstructed, frost formation is likely to grow as described above, and the heating capacity decreases.

ここで、圧縮機７５の吐出側と暖房時の室外熱交換器７３の入口側を連結するバイパス開閉弁７１５ａ、７１５ｂを備えたホットガスバイパス回路を有し、暖房運転時の室外熱交換器７３の除霜をバイパス開閉弁７１５ａまたは７１５ｂを開いて行う空気熱源ヒートポンプ空気調和機において、室外熱交換器７３を上部より下部が小さい複数の冷媒回路に上下方向に分割し、各回路を並列に接続すると共に、室内熱交換器３３と複数の冷媒回路の各々との間に主回路開閉機構７１３ａ、７１３ｂを設け、主回路開閉機構７１３ａ、７１３ｂとバイパス開閉弁７１５ａ、７１５ｂとを交互に開閉して複数の冷媒回路の１回路を除霜しつつ他の回路で暖房運転を継続する。   Here, it has a hot gas bypass circuit provided with bypass opening / closing valves 715a and 715b for connecting the discharge side of the compressor 75 and the inlet side of the outdoor heat exchanger 73 during heating, and the outdoor heat exchanger 73 during heating operation. In an air heat source heat pump air conditioner that performs defrosting of the air by opening the bypass on-off valve 715a or 715b, the outdoor heat exchanger 73 is vertically divided into a plurality of refrigerant circuits whose lower parts are smaller than the upper parts, and the circuits are connected in parallel. In addition, main circuit switching mechanisms 713a and 713b are provided between the indoor heat exchanger 33 and each of the plurality of refrigerant circuits, and the main circuit switching mechanisms 713a and 713b and the bypass switching valves 715a and 715b are alternately opened and closed. The heating operation is continued in another circuit while defrosting one circuit of the plurality of refrigerant circuits.

これにより、除霜していない下側熱交換器７３２又は上側熱交換器を蒸発器として暖房運転が継続できる。また、除霜のとき、圧縮機７５からのホットガスで解氷しなければならない熱交換器の面積が下側熱交換器７３２を除霜する時は狭くなる。この狭い範囲の着霜を暖めれば良いため、除霜に要する時間が短縮される。   Thereby, heating operation can be continued using the lower heat exchanger 732 or the upper heat exchanger that has not been defrosted as an evaporator. Further, when defrosting, the area of the heat exchanger that must be defrosted with hot gas from the compressor 75 becomes narrower when the lower heat exchanger 732 is defrosted. Since it is only necessary to warm this narrow range of frost, the time required for defrosting is shortened.

また、狭い範囲を暖めれば良いため、熱が行き渡り易く、解氷が十分行われ、解けて流下する水滴の温度も上がり、粘性が小さくなって流下し易くなると共に、一部が空気中へ蒸発しやすくなる。このようにして、下側熱交換器７３２に流下しないで残存する水滴の量が減少する。したがって、下側熱交換器７３２は除霜の都度、残存水の少ない、着霜しにくい状態になるので、着霜の進行が遅れる。着霜の進行が遅れると、その分、室外熱交換器７３の除霜の開始を遅らせることができ、室内を除霜・暖房運転で十分に暖房することができる。   In addition, since it is only necessary to warm a narrow range, the heat is easily spread, the ice is sufficiently melted, the temperature of the water droplets that melt and flow down rises, the viscosity becomes small and the flow easily flows down, and part of it goes into the air Evaporates easily. In this way, the amount of water droplets remaining without flowing down to the lower heat exchanger 732 is reduced. Accordingly, since the lower heat exchanger 732 is in a state in which the remaining water is small and frost formation is difficult every time the defrosting is performed, the progress of the frost formation is delayed. If the progress of frost formation is delayed, the start of defrosting of the outdoor heat exchanger 73 can be delayed correspondingly, and the room can be sufficiently heated by defrosting / heating operation.

このため、室内を暖房しながら除霜する除霜・暖房運転が可能で、除霜・暖房運転の所要時間を短縮でき、室内の快適性を長く保つことができる。   For this reason, the defrosting / heating operation for defrosting while heating the room is possible, the time required for the defrosting / heating operation can be shortened, and the comfort in the room can be kept long.

また、一般に、着霜が生じるような温度条件での暖房時は、外気温が低いときが多く、温風の温度を上げるため、高い凝縮温度が要求され、また、圧縮機７５の吸い込み圧力は外気温が低いため、低くなるので、圧縮比が上がり、圧縮機７５の効率が下がってしまう。これを補うため、回転数制御圧縮機を使用するときなどは回転数を上げて、冷媒の循環量を確保する必要がある。また、圧縮機７５の仕事量も暖房能力に加わるので、圧縮機７５を存分に働かせて暖房能力を確保する。このため、圧縮機７５は高負荷で駆動され、圧縮機７５は高温に保持されている。この状態から除霜・暖房運転に入ると、圧縮機７５が高温に保持されているので、圧縮機７５から吐出される冷媒は高温状態でホットガスバイパス回路を流れ、上側熱交換器７３１に流入する。   In general, when heating under a temperature condition where frost formation occurs, the outside air temperature is often low, and a high condensing temperature is required to raise the temperature of the hot air, and the suction pressure of the compressor 75 is Since the outside air temperature is low, the temperature is lowered, so that the compression ratio is increased and the efficiency of the compressor 75 is decreased. In order to compensate for this, it is necessary to increase the number of rotations to ensure the circulation amount of the refrigerant when using a rotation number control compressor. Moreover, since the work amount of the compressor 75 is also added to the heating capacity, the compressor 75 is fully operated to ensure the heating capacity. For this reason, the compressor 75 is driven with a high load, and the compressor 75 is kept at a high temperature. When the defrosting / heating operation is started from this state, since the compressor 75 is kept at a high temperature, the refrigerant discharged from the compressor 75 flows through the hot gas bypass circuit at a high temperature and flows into the upper heat exchanger 731. To do.

また、一般に、室外熱交換器用７３に送風する室外ファン６３１は外気を大量に循環させて、熱交換を効率よく行わせるため、軸流ファン６３１が使用される。軸流ファンは発生できる風圧がさほど大きくないため、室外機６の構造は外気吸込み口、室外熱交換器７３、軸流ファン６３１、外気吹出し口をほぼ一直線に並べ、通風経路を単純な形にして、通風の圧力損失を抑えるように構成されている。   In general, the outdoor fan 631 that blows air to the outdoor heat exchanger 73 circulates a large amount of outside air so that heat exchange can be performed efficiently, so that an axial fan 631 is used. Since the wind pressure that can be generated by the axial fan is not so great, the structure of the outdoor unit 6 is that the outside air inlet, the outdoor heat exchanger 73, the axial fan 631, and the outside air outlet are arranged in a straight line, and the ventilation path is simplified. Thus, the pressure loss of ventilation is suppressed.

このように、わずかな風圧で、大量の外気を通風させるので、室外熱交換器７３を通過する外気の量は通風経路の違いで場所によって変わる。室外熱交換器７３を上下に分けた場合、室外熱交換器７３の下部は上部に比べて地面の影響を強く受け、極わずかではあるが、通風抵抗が増すと考えられる。この僅かな差で、室外熱交換器７３の下部を流れる外気の量がほんの少し減少する。   Thus, since a large amount of outside air is ventilated with a slight wind pressure, the amount of outside air passing through the outdoor heat exchanger 73 varies depending on the location due to the difference in the ventilation path. When the outdoor heat exchanger 73 is divided into an upper part and a lower part, the lower part of the outdoor heat exchanger 73 is strongly influenced by the ground as compared with the upper part, and it is considered that the ventilation resistance is increased although it is very small. With this slight difference, the amount of outside air flowing under the outdoor heat exchanger 73 is slightly reduced.

このため、室外熱交換器７３の上部と下部を比較すると、下側熱交換器７３２は上側熱交換器７３１に比べて、風速が遅くなり、熱交換性能が低下する。このため、下側熱交換器７３２は上側熱交換器７３１に比べて、低温になり、着霜し易くなる。また、室外熱交換器７３の下部は上部から流れてきた上側熱交換器７３１の除霜時の融解水が通過するため、上部より水滴が残り易い。水滴が残った状態で除霜・暖房運転が終了し、暖房運転が始まると、残った水滴が氷結し、室外空気の通風を妨害する。室外空気の通風が妨害されると前述のように、更に、着霜が成長し易くなる。   For this reason, when the upper part and the lower part of the outdoor heat exchanger 73 are compared, the lower heat exchanger 732 has a lower wind speed than the upper heat exchanger 731 and the heat exchange performance is deteriorated. For this reason, the lower heat exchanger 732 has a lower temperature than the upper heat exchanger 731 and is likely to be frosted. Moreover, since the molten water at the time of defrosting of the upper side heat exchanger 731 which flowed from the upper part passes through the lower part of the outdoor heat exchanger 73, a water droplet tends to remain from the upper part. When the defrosting / heating operation is completed with the water droplets remaining and the heating operation is started, the remaining water droplets are frozen to block the ventilation of the outdoor air. If the ventilation of the outdoor air is obstructed, as described above, frost formation is more likely to grow.

そこで、室外熱交換器７３の除霜を行う時に、上側熱交換器７３１、下側熱交換器７３２の順に除霜を行うと共に、下側熱交換器７３２の除霜時間を、先に行った上側熱交換器７３１の除霜時間より長くしている。これにより、室外熱交換器７３に着霜し、着霜量が除霜を必要とする所定量に達したときに、上側熱交換器７３１から順に除霜・暖房運転を行う。まず、上側の冷媒回路にホットガスバイパス回路からのガスを流し、除霜・暖房運転を行う。上側の冷媒回路にホットガスを流すので、室外熱交換器７３の上側の冷媒回路の空気側伝熱面に付着した着霜が融解し、下方に流れ下る。   Therefore, when defrosting the outdoor heat exchanger 73, defrosting was performed in the order of the upper heat exchanger 731 and the lower heat exchanger 732, and the defrosting time of the lower heat exchanger 732 was performed first. It is longer than the defrosting time of the upper heat exchanger 731. As a result, the outdoor heat exchanger 73 is frosted, and when the amount of frost reaches a predetermined amount that requires defrosting, the defrosting / heating operation is performed in order from the upper heat exchanger 731. First, gas from the hot gas bypass circuit is caused to flow through the upper refrigerant circuit to perform defrosting and heating operations. Since hot gas is allowed to flow through the upper refrigerant circuit, frost adhering to the air-side heat transfer surface of the upper refrigerant circuit of the outdoor heat exchanger 73 is melted and flows downward.

この融解水の温度が高い場合は、融解水は下側熱交換器７３２の空気側伝熱面の着霜に触れ、これを融解水自身の顕熱で溶かしながら更に流れ下る。このとき、下側熱交換器７３２で着霜が融解した部分は、熱伝達の妨害をしていた着霜が除かれるので、外気から、冷媒への熱移動がスムーズに行われ、熱交換能力が回復し、室内の暖房能力の低下を抑制する。流れ下る融解水の温度が融解点まで下がると、融解水はそれ以上着霜を融解することなく流下し、流下しながら下側熱交換器内を流れる下側冷媒回路の冷媒で冷却されて凝固する。   When the temperature of the molten water is high, the molten water touches the frost formation on the air side heat transfer surface of the lower heat exchanger 732 and further flows down while melting it with the sensible heat of the molten water itself. At this time, the portion where the frost is melted in the lower heat exchanger 732 is removed from the frost that has interfered with the heat transfer, so that heat is smoothly transferred from the outside air to the refrigerant, and the heat exchange capability Recovers and suppresses the decline in indoor heating capacity. When the temperature of the flowing molten water falls to the melting point, the molten water flows without melting the frost any more, and is cooled by the refrigerant in the lower refrigerant circuit that flows in the lower heat exchanger while flowing down and solidifies. To do.

このとき、融解水の凝固熱は下側冷媒回路の冷媒を温めるので、上側熱交換器で着霜の融解に使用された熱量が回収される。上側熱交換器７３１の除霜のための除霜・暖房運転が終了すると、次に、下側熱交換器７３２の除霜を行うための除霜・暖房運転が開始される。下側の冷媒回路に圧縮機７５からのホットガスを流すので、室外熱交換器７３の下側の冷媒回路の空気側伝熱面に付着した着霜が融解し、下方に流れ下り、下側熱交換器７３の除霜が行われる。   At this time, since the heat of solidification of the molten water warms the refrigerant in the lower refrigerant circuit, the amount of heat used for melting frost in the upper heat exchanger is recovered. When the defrosting / heating operation for defrosting the upper heat exchanger 731 is completed, the defrosting / heating operation for defrosting the lower heat exchanger 732 is then started. Since hot gas from the compressor 75 is caused to flow through the lower refrigerant circuit, frost adhering to the air-side heat transfer surface of the lower refrigerant circuit of the outdoor heat exchanger 73 is melted and flows downward, The heat exchanger 73 is defrosted.

このとき、上側熱交換器７３１は除霜が終了した直後なので、熱伝達の妨害をしていた着霜が除かれているので、外気から、冷媒への熱移動がスムーズに行われ、熱交換能力が回復し、室内の暖房能力の低下を抑制する。このように、除霜・暖房運転時でも暖房能力の大幅な低下を抑制しつつ、暖房を継続することができる。   At this time, since the upper heat exchanger 731 is immediately after the defrosting is completed, the frost formation that has hindered the heat transfer is removed, so that heat transfer from the outside air to the refrigerant is performed smoothly, and heat exchange is performed. The capacity is restored and the decrease in indoor heating capacity is suppressed. Thus, heating can be continued while suppressing a significant decrease in heating capacity even during defrosting / heating operation.

また、上側熱交換器７３１の除霜時には、下側熱交換器７３２の着霜量が一時的に増加する。しかし、上側熱交換器７３１の除霜の終了に引き続いて下側熱交換器７３２の除霜のための除霜・暖房運転が行われるので、下側熱交換器７３２も除霜される。したがって、下側熱交換器７３２の着霜が増え続け、残霜が生ずることはない。このため、着霜を完全に除去でき、残霜を生じさせない。   Further, when the upper heat exchanger 731 is defrosted, the amount of frost formation on the lower heat exchanger 732 temporarily increases. However, since the defrosting / heating operation for defrosting the lower heat exchanger 732 is performed following the end of the defrosting of the upper heat exchanger 731, the lower heat exchanger 732 is also defrosted. Therefore, frost formation of the lower heat exchanger 732 continues to increase, and no residual frost is generated. For this reason, frost formation can be removed completely and residual frost is not produced.

また、最初の除霜・暖房運転では高温のホットガスを上側熱交換器７３１の除霜に使用できるので、除霜・暖房運転の時間は短かいが、広範な範囲を除霜することができる。この時、室内熱交換器３３に送られる冷媒の温度も高温な状態であるので、暖房能力は減少するが、時間が短いため、室温の変動は少なく室内の快適性の低下を抑制することができる。   Moreover, since hot hot gas can be used for defrosting of the upper heat exchanger 731 in the first defrosting / heating operation, the defrosting / heating operation time is short, but a wide range can be defrosted. . At this time, since the temperature of the refrigerant sent to the indoor heat exchanger 33 is also in a high temperature state, the heating capacity is reduced. However, since the time is short, the fluctuation of the room temperature is small and the deterioration of the indoor comfort is suppressed. it can.

このように、除霜・暖房運転の開始からの短時間で、広範な範囲の上側熱交換器７３１の除霜が完了し、下側熱交換器７３２の除霜に切換えることができる。下側熱交換器７３２の除霜のための除霜・暖房運転では、除霜すべき下側熱交換器７３２の範囲は上側熱交換器７３１より狭くなるが、圧縮機７５の吐出ガスの温度が直前に行われた上方の上側熱交換器７３１の除霜・暖房運転のために低下しているので、その除霜・暖房運転の所要時間は長くなる。   Thus, in a short time from the start of the defrosting / heating operation, the defrosting of the upper heat exchanger 731 in a wide range is completed and can be switched to the defrosting of the lower heat exchanger 732. In the defrosting / heating operation for defrosting the lower heat exchanger 732, the range of the lower heat exchanger 732 to be defrosted is narrower than that of the upper heat exchanger 731, but the temperature of the discharge gas of the compressor 75 is reduced. Is decreased due to the defrosting / heating operation of the upper upper heat exchanger 731 performed immediately before, the time required for the defrosting / heating operation becomes longer.

また、下側熱交換器７３２には霜が着きやすいので、その除霜・暖房運転の時間を残霜が生じないよう十分長くする必要がある。しかし、この時は、上側熱交換器７３１の除霜が完了しているので、上側熱交換器７３１はその熱交換能力を十分発揮でき、外気から熱を吸収し、圧縮機７５の吐出温度の低下を抑制し、ホットガスの温度低下を抑えて、除霜・暖房運転できる。これによって、その除霜・暖房運転の所要時間は上方熱交換器の除霜所要時間の２倍程度に抑えられ、上側熱交換器７３１と下側熱交換器７３２の除霜・暖房運転の所要時間の合計を逆サイクル除霜運転した場合に比べて短縮することができる。また、この時、圧縮機７５の吐出温度の低下が抑制されるので、暖房能力の低下も抑制することができる。このため、室内を暖房しながら除霜をすることが可能で、且つ、除霜・暖房運転の所要時間を短縮できる。   In addition, since frost easily forms on the lower heat exchanger 732, it is necessary to sufficiently lengthen the time for the defrosting / heating operation so that no residual frost is generated. However, at this time, since the defrosting of the upper heat exchanger 731 is completed, the upper heat exchanger 731 can sufficiently exhibit its heat exchange capability, absorbs heat from the outside air, and the discharge temperature of the compressor 75 The defrosting and heating operation can be performed by suppressing the decrease and suppressing the temperature decrease of the hot gas. Thereby, the time required for the defrosting / heating operation is suppressed to about twice the time required for the defrosting of the upper heat exchanger, and the defrosting / heating operation required for the upper heat exchanger 731 and the lower heat exchanger 732 is required. The total time can be shortened compared to the case where the reverse cycle defrosting operation is performed. Moreover, since the fall of the discharge temperature of the compressor 75 is suppressed at this time, the fall of heating capability can also be suppressed. For this reason, defrosting can be performed while heating the room, and the time required for the defrosting / heating operation can be shortened.

一般に、効率よく暖房運転するため、暖房運転時の圧縮機７５の吐出温度は７０℃前後に制御されている。高圧チャンバーを有する圧縮機７５では、この吐出冷媒が高圧チャンバー内に充満するため、圧縮機７５全体が高温に保たれる。また、室外熱交換器７３の除霜を終了した後、暖房運転の立上がりを良くするため、除霜終了時の圧縮機７５の吐出温度は室温以上であることが要求され、圧縮機７５から室内熱交換器３３までの温度低下を考慮すると、２５℃以上であることが望ましい。   Generally, in order to efficiently perform the heating operation, the discharge temperature of the compressor 75 during the heating operation is controlled around 70 ° C. In the compressor 75 having the high-pressure chamber, the discharged refrigerant fills the high-pressure chamber, so that the entire compressor 75 is kept at a high temperature. In addition, after the defrosting of the outdoor heat exchanger 73 is finished, the discharge temperature of the compressor 75 at the end of the defrosting is required to be equal to or higher than room temperature in order to improve the start-up of the heating operation. Considering the temperature drop to the heat exchanger 33, it is desirable that the temperature is 25 ° C. or higher.

本実施例では、除霜の禁止期間を短くし、室外熱交換器７３に付着する着霜の量を制限して圧縮機７５に蓄えられた熱量で除霜を終了することにより、除霜の所要時間を短縮でき、暖房に復帰した後の暖房能力の回復を早くすることができる、と言う発想の下に成されたものである。   In the present embodiment, the defrosting prohibition period is shortened, the amount of frost adhering to the outdoor heat exchanger 73 is limited, and the defrosting is terminated with the amount of heat stored in the compressor 75, thereby removing the defrosting. It is based on the idea that the required time can be shortened and the recovery of the heating capacity after returning to heating can be accelerated.

ここで、鋼鉄製の外殻を持つ圧縮機７５、四方弁７２、室内熱交換器３３、減圧装置７４、アルミニウム製のフィンを持つ室外熱交換器７３を備え、外気温０℃以上のときの除霜禁止期間を次の式（１）の数値以下とする。   Here, a compressor 75 having a steel outer shell, a four-way valve 72, an indoor heat exchanger 33, a pressure reducing device 74, an outdoor heat exchanger 73 having aluminum fins, and an outdoor temperature of 0 ° C. or more are provided. The defrosting prohibition period is set equal to or less than the numerical value of the following formula (1).

最長除霜禁止期間（分）＝８×圧縮機の質量（ｋｇ）÷室外熱交換器の吸熱量（ｋＷ） … （１）
これにより、高温の圧縮機に蓄えられている７０℃〜２５℃の熱量を室外熱交換器７３の除霜に使用し、室内から熱を奪わないようにできる。例えば、暖房能力６．７ｋＷクラスの空気調和機では、圧縮機７５の質量は１２ｋｇ程度である。そのため、利用できる蓄熱量Ｑは、大略、１２（質量）×０．４３５（比熱：概算のためすべて鋼鉄でできていると仮定する）×（７０−２５）＝２３５ｋＪである。 Maximum defrosting prohibition period (minutes) = 8 × compressor mass (kg) ÷ outdoor heat exchanger heat absorption (kW) (1)
Thereby, the amount of heat of 70 ° C. to 25 ° C. stored in the high-temperature compressor can be used for defrosting the outdoor heat exchanger 73 so that heat is not taken away from the room. For example, in an air conditioner with a heating capacity of 6.7 kW class, the mass of the compressor 75 is about 12 kg. Therefore, the heat storage amount Q that can be used is approximately 12 (mass) × 0.435 (specific heat: it is assumed that all are made of steel for estimation) × (70−25) = 235 kJ.

しかしこのとき、室外熱交換器７３の温度は−５℃程度になっているため、着霜と室外熱交換器７３が０℃まで上昇するのに必要な熱量も加えてやる必要がある。その熱量はおよそ蓄熱量Ｑの１割と見て差し支えないので、着霜の融解に使用できる熱量は２３５−２４＝２１１ｋＪとなる。   However, at this time, since the temperature of the outdoor heat exchanger 73 is about -5 ° C, it is necessary to add frosting and the amount of heat necessary for the outdoor heat exchanger 73 to rise to 0 ° C. Since the amount of heat can be regarded as about 10% of the amount of stored heat Q, the amount of heat that can be used for melting frost is 235-24 = 211 kJ.

一方、このクラスの空気調和機の室外送風装置６３の風量は１２．５ｍ３／ｍｉｎ程度であり、外気温が５℃／４℃（ＤＢ／ＷＢ）付近の着霜量の多い運転では、室外熱交換器７３の吸熱量は４．０ｋＷと見積もられる。その時の室外熱交換器７３の平均温度は−４℃位で、顕熱比は０．６５、着霜量は１．９ｋg／ｈとなる。この着霜の融解に必要な熱量は６３４ｋJとなる。これより、除霜禁止期間を（２３５−２４）÷６３４＝０．３３時間＝２０分以内にすれば、圧縮機７５の蓄熱だけで室外熱交換器７３の除霜ができることになる。 On the other hand, the outdoor air blower 63 of the air conditioner of this class has an air volume of about 12.5 m 3 / min, and the outdoor air temperature is about 5 ° C / 4 ° C (DB / WB). The heat absorption amount of the heat exchanger 73 is estimated to be 4.0 kW. The average temperature of the outdoor heat exchanger 73 at that time is about −4 ° C., the sensible heat ratio is 0.65, and the amount of frost formation is 1.9 kg / h. The amount of heat necessary for melting this frost is 634 kJ. Thus, if the defrosting prohibition period is set within (235-24) ÷ 634 = 0.33 hours = 20 minutes, the outdoor heat exchanger 73 can be defrosted only by heat storage of the compressor 75.

ここで、空気熱源ヒートポンプ空気調和機の暖房能力測定条件はＩＳＯ規格で外気の状態を７℃／６℃（ＤＢ／ＷＢ）でとしているので、この条件では除霜運転に入らないように設計することにより、外気温度が５℃より高くなると室外熱交換器７３の温度が上がり、ほとんど着霜しなくなる。他方、外気温度が５℃より下がると外気の絶対湿度が下がってくるため、着霜量が少なくなってくる。このため、計算例では着霜量が一番多くなる外気温度５℃付近を例に取った。   Here, since the heating capacity measurement condition of the air heat source heat pump air conditioner is set to 7 ° C / 6 ° C (DB / WB) according to ISO standards, it is designed not to enter the defrosting operation under this condition. Thus, when the outside air temperature becomes higher than 5 ° C., the temperature of the outdoor heat exchanger 73 rises, and frost formation hardly occurs. On the other hand, when the outside air temperature falls below 5 ° C., the absolute humidity of the outside air falls, so the amount of frost formation decreases. For this reason, in the calculation example, the outside air temperature around 5 ° C. where the amount of frost formation is the largest is taken as an example.

また、室外送風装置６３の送風量を１２．５ｍ３／ｍｉｎ程度としたが、風量が変わって、室外熱交換器７３の温度が変化しても、この温度付近の飽和水蒸気線の傾きは、図３に示すように前述の顕熱比の値とほぼ同じであるので、変化した後の顕熱比も０．６５となる。従って、着霜量も変わらず、１．９ｋｇ／ｈとなる。つまり、吸熱量が一定であれば（暖房能力が一定であれば）、この温度付近での暖房運転では、着霜量が一定となる。 Moreover, although the air flow rate of the outdoor air blower 63 is set to about 12.5 m 3 / min, even if the air flow rate changes and the temperature of the outdoor heat exchanger 73 changes, the slope of the saturated water vapor line near this temperature is As shown in FIG. 3, since the value of the sensible heat ratio is almost the same as described above, the sensible heat ratio after the change is also 0.65. Therefore, the amount of frost formation does not change and is 1.9 kg / h. That is, if the heat absorption amount is constant (if the heating capacity is constant), the amount of frost formation is constant in the heating operation near this temperature.

このように、圧縮機７５の質量と暖房能力が判れば、圧縮機７５の蓄熱量だけで除霜できる着霜量に達するまでの大略の暖房運転時間を求め、この運転時間より短い時間を除霜禁止期間とする。更に、室外熱交換器７３を上下に複数の冷媒回路に分割し、除霜・暖房運転時に分割した少なくとも１以上の冷媒回路を蒸発器として作用させる。これにより、除霜・暖房運転時も蒸発器として作用している室外熱交換器７３の一部からの吸熱量と圧縮機７５の電気入力分が室内の暖房に寄与することができ、室内機２の暖房能力の低下を抑制して、室内の温度低下を抑えることができる。このため、室内の快適感が失われるのを防止できる。   Thus, if the mass and heating capacity of the compressor 75 are known, the approximate heating operation time until the frost formation amount that can be defrosted only by the heat storage amount of the compressor 75 is obtained, and the time shorter than this operation time is excluded. The frost prohibition period. Furthermore, the outdoor heat exchanger 73 is vertically divided into a plurality of refrigerant circuits, and at least one refrigerant circuit divided during the defrosting / heating operation is caused to act as an evaporator. As a result, the amount of heat absorbed from a part of the outdoor heat exchanger 73 acting as an evaporator during defrosting / heating operation and the electric input of the compressor 75 can contribute to indoor heating. It is possible to suppress a decrease in the indoor temperature by suppressing a decrease in the heating capacity 2. For this reason, it is possible to prevent loss of comfort in the room.

また、除霜禁止期間を２０分〜５分とする。これにより、ほぼ全ての暖房能力クラスで、室外熱交換器７３の着霜の量が制限され、圧縮機７５の蓄熱だけで除霜・暖房運転時の除霜熱量を賄うことができる。このため、室内の快適感が失われるのを防止できる。   The defrosting prohibition period is set to 20 minutes to 5 minutes. Thereby, in almost all heating capacity classes, the amount of frost formation of the outdoor heat exchanger 73 is limited, and the amount of defrost heat during the defrosting / heating operation can be covered only by the heat storage of the compressor 75. For this reason, it is possible to prevent loss of comfort in the room.

また、外気温の低下に伴い、圧縮機７５の吐出温度を高温側にシフトして制御すると共に、除霜禁止期間を短縮する。これにより、圧縮機７５の蓄熱量が増加すると共に、除霜・暖房運転時間が短縮され、暖房運転に復帰した時の圧縮機７５の吐出温度の回復が早くなって、暖房能力の落ち込み時間が短くなる。このため、低外気温でも除霜・暖房運転時の室温変化が抑制される。   Further, as the outside air temperature decreases, the discharge temperature of the compressor 75 is shifted to the high temperature side and controlled, and the defrosting prohibition period is shortened. As a result, the amount of heat stored in the compressor 75 increases, the defrosting / heating operation time is shortened, the recovery of the discharge temperature of the compressor 75 when the operation returns to the heating operation is accelerated, and the heating capacity fall time is reduced. Shorter. For this reason, the room temperature change at the time of defrosting and heating operation is suppressed even at a low outside temperature.

また、除霜・暖房運転時は暖房運転時よりも室外ファン６３１の回転数を低下させ、更に、外気温度が所定値より低い場合は除霜運転時に室外送風機の運転を停止する。このように、除霜・暖房運転時に室外ファン６３１の回転数を低下させることにより、除霜・暖房運転時に融解水やフィン、パイプから、室外ファン６３１による強制対流で外気に奪い去られる熱量が減少し、霜の融解が効率よく進む。また、外気の温度が更に低くなり、外気への放熱量が増加した場合は室外ファン６３１の運転を停止する。これにより、室外ファン６３１による強制対流で外気に奪い去られる熱量の大部分が霜の融解に有効に使用され、室外熱交換器７３の除霜が効率よく進む。このため、除霜・暖房運転時間を短縮でき、また、低外気温の時でも除霜・暖房運転で残霜を生じることはない。   In addition, during the defrosting / heating operation, the rotational speed of the outdoor fan 631 is reduced as compared with that during the heating operation. Further, when the outside air temperature is lower than a predetermined value, the operation of the outdoor fan is stopped during the defrosting operation. Thus, by reducing the rotational speed of the outdoor fan 631 during the defrosting / heating operation, the amount of heat taken away from the melted water, fins, and pipes by forced convection by the outdoor fan 631 during the defrosting / heating operation. Decreases and frost melting progresses efficiently. Further, when the temperature of the outside air is further lowered and the amount of heat released to the outside air is increased, the operation of the outdoor fan 631 is stopped. As a result, most of the amount of heat removed to the outside air by forced convection by the outdoor fan 631 is effectively used for melting frost, and the defrosting of the outdoor heat exchanger 73 proceeds efficiently. For this reason, the defrosting / heating operation time can be shortened, and no residual frost is generated by the defrosting / heating operation even at a low outside air temperature.

また、除霜運転を最長除霜運転時間に達するまで行っても室外熱交換器７３の温度が所定値に達しない場合に四方弁７２を切換えて逆サイクル除霜運転を行う。これにより、暖房サイクルでのホットガスバイパス除霜で融解し切れなかった室外熱交換器７３の冷媒回路出口（冷房時の室外熱交換器入口）付近の残霜も、逆サイクル除霜運転を行うことにより、圧縮機７５からの高温冷媒で融解させることができる。   Further, when the temperature of the outdoor heat exchanger 73 does not reach a predetermined value even if the defrosting operation is performed until the longest defrosting operation time is reached, the reverse cycle defrosting operation is performed by switching the four-way valve 72. Thereby, the reverse frost defrosting operation is also performed on the residual frost in the vicinity of the refrigerant circuit outlet (outdoor heat exchanger inlet during cooling) of the outdoor heat exchanger 73 that was not completely melted by the hot gas bypass defrosting in the heating cycle. Thus, the high-temperature refrigerant from the compressor 75 can be melted.

このように、設置条件や、気象条件の悪化で通常の除霜・暖房運転では残霜が発生する場合でも、残霜無しの完全な除霜運転を行うことができる。このため、室内の暖房ができる設置条件や気象条件の範囲を広くすることができる。   Thus, even when residual frost is generated in normal defrosting / heating operation due to deterioration of installation conditions and weather conditions, complete defrosting operation without residual frost can be performed. For this reason, the range of the installation conditions and weather conditions which can be heated indoors can be widened.

次に、本実施例による暖房の立上がり特性について、図８を参照しながら説明する。図８は図１の空気調和機の暖房の立上り運転時の室温変化を示す特性図である。ここでは、寒い朝を想定し、室温、外気温が共に−５℃の状態からスタートさせた。   Next, the rising characteristics of heating according to the present embodiment will be described with reference to FIG. FIG. 8 is a characteristic diagram showing a change in room temperature during the start-up operation of the air conditioner of FIG. Here, assuming a cold morning, both the room temperature and the outside temperature were started at −5 ° C.

図８の特性に示すように、本実施例による暖房運転と除霜・暖房運転とによる方式では除霜の運転時間が約２分と短く、また、除霜・暖房運転中も室外熱交換器の一部は蒸発器として作用して室内の暖房をしているため、室内温度の低下も約３℃程度の抑えられ、快適性が確保して暖房が継続される。また、室内温度の２０℃までの到達時間は８０分と短い。   As shown in the characteristics of FIG. 8, in the heating operation and the defrosting / heating operation method according to this embodiment, the defrosting operation time is as short as about 2 minutes, and the outdoor heat exchanger is also used during the defrosting / heating operation. Since some of them act as an evaporator to heat the room, a decrease in the room temperature is suppressed to about 3 ° C., and comfort is ensured and heating is continued. In addition, the time required for the room temperature to reach 20 ° C. is as short as 80 minutes.

本発明の一実施例の空気調和機の構成図である。It is a block diagram of the air conditioner of one Example of this invention. 図１の空気調和機の冷凍サイクル構成図である。It is a refrigerating cycle block diagram of the air conditioner of FIG. 除霜時の室外空気の変化を示す湿り空気線図である。It is a humid air line figure which shows the change of the outdoor air at the time of defrosting. 図１の空気調和機の冷房運転時の冷媒の流れを示す冷凍サイクル図である。It is a refrigerating cycle figure which shows the flow of the refrigerant | coolant at the time of air_conditionaing | cooling operation of the air conditioner of FIG. 図１の空気調和機の暖房運転時の冷媒の流れを示す冷凍サイクル図である。It is a refrigerating cycle figure which shows the flow of the refrigerant | coolant at the time of the heating operation of the air conditioner of FIG. 図１の空気調和機の室外熱交換器の上部を除霜する時の冷媒の流れを示す冷凍サイクル図である。It is a refrigerating cycle figure which shows the flow of a refrigerant | coolant at the time of defrosting the upper part of the outdoor heat exchanger of the air conditioner of FIG. 図１の空気調和機の室外熱交換器の下部を除霜する時の冷媒の流れを示す冷凍サイクル図である。It is a refrigerating cycle figure which shows the flow of the refrigerant | coolant when defrosting the lower part of the outdoor heat exchanger of the air conditioner of FIG. 図１の空気調和機の暖房の立上り運転時の室温変化を示す特性図である。It is a characteristic view which shows the room temperature change at the time of the start-up operation of the heating of the air conditioner of FIG.

符号の説明Explanation of symbols

１…空気調和機、２…室内機、５…リモコン、６…室外機、８…接続配管、１０…制御装置、３３…室内熱交換器、７２…四方弁、７３…室外熱交換器、７４…減圧装置、７５…圧縮機、７６…アキュムレータ、３１１…室内ファン、３１３…室内送風モーター、６３１…室外ファン、６３３…室外送風モーター、７１０…吸込配管、７１１…吐出配管、７１２…利用側ガス管、７１３…液管、７１４…熱源側ガス管、７１５…ホットガスバイパス管、７１３ａ…上側主回路開閉弁、７１３ｂ…下側主回路開閉弁、７１３ｄ…ホットパイプ、７１５ａ…上側バイパス開閉弁、７１５ｂ…下側バイパス開閉弁、７１６ａ…上側バイパス管、７１６ｂ…下側バイパス管、７３１…上側熱交換器、７３１ａ…第１上側冷媒回路、７３１ｂ…第２上側冷媒回路、７３１ｃ…第３上側冷媒回路、７３２…下側熱交換器、７３２ａ…第１下側冷媒回路、７３２ｂ…第２下側冷媒回路、８１１ａ…冷媒温検知センサー、８１１ｂ…冷媒温検知センサー、８１２…冷媒温検知センサー。   DESCRIPTION OF SYMBOLS 1 ... Air conditioner, 2 ... Indoor unit, 5 ... Remote control, 6 ... Outdoor unit, 8 ... Connection piping, 10 ... Control apparatus, 33 ... Indoor heat exchanger, 72 ... Four-way valve, 73 ... Outdoor heat exchanger, 74 DESCRIPTION OF SYMBOLS ... Pressure reducing device, 75 ... Compressor, 76 ... Accumulator, 311 ... Indoor fan, 313 ... Indoor fan motor, 631 ... Outdoor fan, 633 ... Outdoor fan motor, 710 ... Suction pipe, 711 ... Discharge pipe, 712 ... User side gas Pipe, 713 ... Liquid pipe, 714 ... Heat source side gas pipe, 715 ... Hot gas bypass pipe, 713a ... Upper main circuit on / off valve, 713b ... Lower main circuit on / off valve, 713d ... Hot pipe, 715a ... Upper bypass on / off valve, 715b: Lower bypass on-off valve, 716a ... Upper bypass pipe, 716b ... Lower bypass pipe, 731 ... Upper heat exchanger, 731a ... First upper refrigerant circuit, 731b ... Second upper side Medium circuit, 731c ... third upper refrigerant circuit, 732 ... lower heat exchanger, 732a ... first lower refrigerant circuit, 732b ... second lower refrigerant circuit, 811a ... refrigerant temperature detection sensor, 811b ... refrigerant temperature detection sensor 812 ... Refrigerant temperature detection sensor.

Claims (7)

圧縮機、四方弁、室内熱交換器、減圧装置及び室外熱交換器を冷媒配管で連結して冷凍サイクルを構成し、
前記室外熱交換器を２つに分けて並列に接続すると共に、前記２つに分けられた各室外熱交換器の冷媒回路の暖房運転時入口側に主回路開閉機構を設け、
前記圧縮機の吐出側と前記２つに分けられた各室外熱交換器の冷媒回路の暖房運転時入口側とを連結するホットガスバイパス回路を設けると共に、ホットガスバイパス回路にバイパス開閉弁を設け、
運転を制御する制御装置を備えた空気調和機において、
前記室外熱交換器は、その冷媒回路を上下に２つに分けて、下側熱交換器とこの下側熱交換器より大きい上側熱交換器とを構成し、
前記制御装置は、暖房運転中に除霜を開始する場合に、前記主回路開閉機構及び前記バイパス開閉弁を逆に開閉して、前記上側熱交換器を除霜しつつ前記下側熱交換器で暖房する除霜・暖房運転をした後に、前記下側熱交換器を除霜しつつ前記上側熱交換器で暖房する除霜・暖房運転をし、この除霜・暖房運転の終了後に暖房運転に復帰するように制御する
ことを特徴とする空気調和機。 A compressor, a four-way valve, an indoor heat exchanger, a decompressor and an outdoor heat exchanger are connected by a refrigerant pipe to constitute a refrigeration cycle,
The outdoor heat exchanger is divided into two and connected in parallel, and a main circuit opening / closing mechanism is provided on the inlet side of the refrigerant circuit of each of the two outdoor heat exchangers during heating operation,
A hot gas bypass circuit is provided to connect the discharge side of the compressor and the inlet side of the refrigerant circuit of each of the two outdoor heat exchangers divided in the heating operation, and a bypass opening / closing valve is provided in the hot gas bypass circuit. ,
In an air conditioner equipped with a control device for controlling operation,
The outdoor heat exchanger divides the refrigerant circuit into two parts, and constitutes a lower heat exchanger and an upper heat exchanger larger than the lower heat exchanger,
When the control device starts defrosting during heating operation, the lower heat exchanger defrosts the upper heat exchanger by reversely opening and closing the main circuit opening and closing mechanism and the bypass on-off valve. After defrosting / heating operation, heating is performed using the upper heat exchanger while defrosting / heating the lower heat exchanger, and heating operation is performed after the defrosting / heating operation is completed. An air conditioner that is controlled to return to 請求項１において、前記制御装置は、前記上側熱交換器を除霜しつつ前記下側熱交換器で暖房する除霜・暖房運転の時間よりも前記下側熱交換器を除霜しつつ前記上側熱交換器で暖房する除霜・暖房運転の時間を長くすることを特徴とする空気調和機。   2. The control device according to claim 1, wherein the control device defrosts the lower heat exchanger while defrosting the upper heat exchanger, and defrosting the lower heat exchanger from a time of defrosting / heating operation in which heating is performed by the lower heat exchanger. An air conditioner characterized in that the defrosting / heating operation time for heating with the upper heat exchanger is lengthened. 請求項１において、鋼鉄製の外殻を持つ圧縮機を用い、外気温０℃以上のときの除霜禁止期間を次の式（１）の数値以下とすることを特徴とする空気調和機。
除霜禁止期間（単位：分）＝８×圧縮機の質量（単位：ｋｇ）／室外熱交換器の吸熱量（単位：ｋＷ） … （１） The air conditioner according to claim 1, wherein a compressor having a steel outer shell is used, and the defrosting prohibition period when the outside air temperature is 0 ° C or higher is set to be equal to or less than a numerical value of the following equation (1).
Defrosting prohibition period (unit: minute) = 8 × mass of compressor (unit: kg) / heat absorption amount of outdoor heat exchanger (unit: kW) (1) 請求項３において、前記除霜禁止期間を２０分〜５分とすることを特徴とする空気調和機。   The air conditioner according to claim 3, wherein the defrosting prohibition period is 20 minutes to 5 minutes. 請求項１において、前記制御装置は、外気温の低下に基づいて、前記圧縮機の吐出温度を高温側にシフトして制御すると共に、除霜禁止期間を短縮するように制御することを特徴とする空気調和機。   The control device according to claim 1, wherein the control device controls the discharge temperature of the compressor by shifting to a high temperature side based on a decrease in outside air temperature, and controls the defrosting prohibition period to be shortened. Air conditioner to do. 請求項１において、前記制御装置は、除霜・暖房運転時に暖房運転時よりも室外送風装置の回転数を低下させ、更に、外気温度が所定値より低い場合の除霜運転時に室外送風装置の運転を停止するように制御することを特徴とする空気調和機。   In Claim 1, the said control apparatus reduces the rotation speed of an outdoor air blower at the time of a defrost / heating operation rather than the time of a heating operation, and also the outdoor air blower of the outdoor air blower at the time of a defrost operation in case outdoor temperature is lower than predetermined value. An air conditioner that is controlled to stop operation. 請求項１において、前記制御装置は、除霜・暖房運転を除霜運転時間に達するまで行っても前記室外熱交換器の温度が所定値に達しない場合に前記四方弁を切換えて逆サイクル除霜運転を行うように制御することを特徴とする空気調和機。   The control device according to claim 1, wherein the controller switches the four-way valve to remove the reverse cycle when the temperature of the outdoor heat exchanger does not reach a predetermined value even if the defrosting / heating operation is performed until the defrosting operation time is reached. An air conditioner controlled to perform frost operation.
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