JP2005291552A - Multi-air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-air conditioner capable of performing protective control for recovering a refrigerant and lubricating oil, without impairing an air-conditioning feeling, regardless of cooling operation and heating operation. <P>SOLUTION: This multi-air conditioner has an outdoor machine unit 10, and a plurality of indoor machine units 20A, 20B and 20C connected to the outdoor machine unit 10 and capable of respectively controlling original operation. The multi-air conditioner has a refrigerant gathering-in protective control operation mode performed when cumulative time T of compressor actual operation time calculated on the basis of starting time of air-conditioning operation for satisfying a predetermined condition reaches predetermined preset time, and operating a compressor 11 by fully opening the whole electronic expansion valves 14A, 14B and 14C respectively arranged in a refrigerant circulating passage of the indoor machine units 20A, 20B and 20C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a multi-type air conditioner that includes a plurality of indoor unit units that eject conditioned air by air conditioning operation (cooling operation, heating operation, and dehumidifying operation) and that can perform different operation control for each indoor unit.

An air conditioner that performs indoor air conditioning and dehumidification (hereinafter collectively referred to as “air conditioning”) has a configuration in which an indoor unit and an outdoor unit are connected by a refrigerant pipe and an electrical wiring. Such an air conditioner uses a heat pump that forms a refrigerant circulation circuit with a compressor, an outdoor heat exchanger, a throttle mechanism, an indoor heat exchanger, and a four-way valve as main components, and is sent from the compressor. The desired air conditioning operation is performed by switching the circulation direction of the refrigerant by operating the four-way valve.
In such an air conditioner, a single type of configuration in which one indoor unit is connected to a set of outdoor unit and a configuration in which a plurality of indoor unit units each enabling independent operation control are connected There are multiple types.

  In the above-described air conditioner, the lubricating oil used for the lubrication of the compressor becomes mist in the compressor, is sent together with the gas refrigerant, and circulates in the refrigerant circulation path of the refrigeration cycle. For this reason, refrigerant and lubricating oil may remain and accumulate in the circulation path other than the compressor due to operation stop, etc., so that this is collected and prevented from deficient in the refrigerant and lubricating oil due to accumulation. Protection control is performed. The problem of such accumulation is that each indoor unit performs its own operation control, so that indoor units that are operating and stopped are mixed, and the piping length to the indoor unit is long. Since the height difference of the installation position tends to increase, it is particularly likely to occur in a multi-type air conditioner.

In the conventional air conditioner, the following control technique is implemented in order to collect the refrigerant and lubricating oil in the circulation path and prevent accumulation.
(A) Low rotation speed continuous operation protection control When the compressor continues to operate at a low rotation speed, the rotation speed of the compressor is increased for the purpose of collecting the refrigerant and lubricating oil that have flowed out.
(B) Refrigerant accumulation protection control When the multi-type air conditioner is operated continuously for a long time, it is carried out for the purpose of recovering refrigerant and lubricating oil from the indoor unit that has stopped the heating operation. In this protection control, when the cumulative operation time of the compressor has passed a predetermined time (for example, 4 hours), the recovery operation is performed by operating the compressors after fully opening the electronic expansion valves of all the indoor unit units. .

Further, in the conventional multi-type air conditioner, in order to prevent the lubricating oil from accumulating along with the liquid refrigerant condensed in the pipe in the refrigerant line on the compressor discharge side where the refrigerant gas does not circulate in the selected operation state, A system is disclosed that is provided with an oil return pipe that branches off from the refrigerant pipe and is connected to the compressor suction side to overflow a small amount of refrigerant. As a result, a very small amount of refrigerant flows to the compressor suction side via the refrigerant discharge side refrigerant line and the oil return line, so that accumulation of refrigerant and lubricating oil can be prevented. (For example, see Patent Document 1)
JP-A-5-149644

However, the following problems have been pointed out in the above-described prior art.
In the low rotational speed continuous operation protection control in (a), when applied to a multi-type air conditioner that independently controls the operation of a plurality of indoor unit units, the rotational speed of the compressor is simply increased. Only the indoor unit in operation is made, and therefore refrigerant and lubricating oil cannot be recovered from the stopped indoor unit.
In the refrigerant pool protection control (b), although the original purpose is to prevent the stop unit from pooling, it is similarly implemented even when all the indoor unit units are in operation. Has a problem. In other words, when all indoor unit units are in operation, there is no worry of accumulation, and since the operation is out of the proper operating point during the protective operation, from the viewpoint of air conditioning feeling and compressor protection However, it is not preferable to carry out excessive protection control.

In the cooling operation, since the refrigerant in the indoor heat exchanger is sucked by the compressor, the refrigerant circulation system path is configured so that the refrigerant and the lubricating oil hardly accumulate in the heat exchanger. However, in the case of heating operation, the circulation direction is reversed, and a refrigerant circulation system configured such that the refrigerant in the indoor heat exchanger passes through the electronic expansion valve and is sucked into the compressor. For this reason, since the refrigerant and the lubricating oil during the heating operation are blocked by the fully-expanded electronic expansion valve even if the compressor is sucked in, the refrigerant and the lubricating oil are easily collected in the stopped indoor unit.
Also, if the electronic expansion valve of the indoor unit that is stopped for protection control is opened, the refrigerant flows through the indoor unit and generates a flow noise. The unnatural phenomenon that occurs is not preferable.
In addition, since the refrigerant circulates in a state where the electronic expansion valve is fully opened and is not throttled, a liquid back in which the refrigerant flows into the compressor in a liquid phase is likely to occur. Such a liquid bag is not preferable because it causes damage to the compressor.

As described above, in the conventional refrigerant pool protection control described above, even when all the indoor unit units are operated and it is not necessary to worry about the accumulation of the refrigerant and the lubricating oil, the control points deviate from the proper operation point. In view of air conditioning feeling and compressor protection, there is a problem that undesired operation is performed.
The present invention has been made in view of the above circumstances, and the object of the present invention is to implement protection control for recovering refrigerant and lubricating oil without impairing the air conditioning feeling regardless of the cooling operation and the heating operation. An object of the present invention is to provide a multi-type air conditioner that is made possible.

In order to solve the above problems, the present invention employs the following means.
A multi-type air conditioner according to the present invention is an multi-type air conditioner comprising an outdoor unit and a plurality of indoor unit units that are connected to the indoor unit and enable independent operation control. The refrigerant circulation path of the indoor unit is implemented when the cumulative time (T) of the compressor actual operation time accumulated on the basis of the start time of the air conditioning operation that satisfies the predetermined condition reaches a predetermined set time. Are provided with a refrigerant accumulation protection control operation mode in which the compressor is operated by fully opening all of the electronic expansion valves provided in each.

  According to such a multi-type air conditioner, when the cumulative time (T) of the compressor actual operation time accumulated on the basis of the start time of the air-conditioning operation that satisfies the predetermined condition reaches a predetermined set time. Since it is provided with a refrigerant accumulation protection control operation mode in which all of the electronic expansion valves provided in the refrigerant circulation path of the indoor unit are fully opened and the compressor is operated, the cooling operation and the heating operation are provided. Regardless of the case, the refrigerant and the lubricating oil flow through the refrigerant circulation path including all the indoor unit units. For this reason, the refrigerant and lubricating oil accumulated in the stopped indoor unit and the like flow out by this flow and return to the compressor.

  In the multi-type air conditioner described above, in the refrigerant accumulation protection control operation mode, it is preferable that the operation speed of the compressor is once reduced to a minimum and then the electronic expansion valve is fully opened. The flow noise can be kept small by minimizing the circulation amount. Further, since the refrigerant circulation amount is reduced, it is possible to prevent the liquid back flowing into the compressor in the liquid phase by fully opening the electronic expansion valve.

  In the above-described multi-type air conditioner, the refrigerant accumulation protection control mode has a predetermined delay time before fully opening the electronic expansion valve installed in the refrigerant circulation system path where the indoor unit is stopped. Preferably, the electronic expansion valve is fully opened in a state where the number of rotations of the compressor is reduced and the pressure ratio is reduced, so that the noise of refrigerant flow noise can be reduced. That is, the refrigerant flow noise generated for protection control can be minimized from the indoor unit that does not have operation noise because the operation is originally stopped, and unnatural feeling of unnatural operation noise can be reduced.

  In the multi-type air conditioner described above, the end of the refrigerant accumulation protection control mode is performed by returning the opening of the electronic expansion valve before the start of protection control and then returning the rotational speed of the compressor before the start of protection control. Thus, in the indoor unit that is stopped, it is possible to prevent the operation noise of the refrigerant flow noise and to prevent the liquid back in which the liquid refrigerant that cannot be throttled by the electronic expansion valve flows into the compressor. .

  The multi-type air conditioner according to the present invention described above is used when the cumulative time (T) of the compressor actual operation time accumulated on the basis of the start time of the air conditioning operation that satisfies the predetermined condition has reached a predetermined set time. Since it has a refrigerant accumulation protection control operation mode in which all the electronic expansion valves provided in the refrigerant circulation system path of the indoor unit are fully opened and the compressor is operated, the cooling operation and the heating operation are performed. Regardless, the refrigerant and lubricating oil flow through the refrigerant circulation system including all indoor unit units, and the refrigerant and lubricating oil accumulated in the stopped indoor unit units can be returned to the compressor and recovered. it can. For this reason, it is possible to recover the refrigerant and lubricating oil from the stopped indoor unit, and the protection control is performed every accumulated time of the compressor actual operation time, so that the protection control is frequently performed. There is no. Therefore, it is possible to reduce the operation that impairs the air conditioning feeling and the operation in a severe state for the compressor that is out of the proper operating point.

In the refrigerant accumulation protection control operation mode of the present invention, the flow noise of the refrigerant can be suppressed by performing the following control. In particular, the generation of a flowing sound from a stopped indoor unit gives a sense of incongruity to the user. Therefore, reducing this noise is extremely effective for improving the merchantability.
Reducing the operating speed of the compressor to the minimum and then fully opening the electronic expansion valve Refrigerant pool providing a predetermined delay time before fully opening the electronic expansion valve installed in the stopped refrigerant circulation system The end of the protection control mode is completed by returning the opening of the electronic expansion valve before the start of protection control and then returning the rotational speed of the compressor before the start of protection control.

Further, in the refrigerant accumulation protection control operation mode of the present invention, when the electronic expansion valve is fully opened, it is possible to prevent the liquid back from flowing into the compressor in the liquid phase due to the decrease in the refrigerant circulation amount, and further, Since the liquid back that liquid refrigerant that cannot be throttled by the electronic expansion valve flows into the compressor can also be prevented, it is possible to protect the compressor from damage caused by the liquid back. .

Hereinafter, an embodiment of a multi-type air conditioner according to the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory diagram illustrating an example of the overall configuration of a multi-type air conditioner. The multi-type air conditioner includes an outdoor unit 10 and a plurality of indoor unit units 20 (in the illustrated example, three indoor unit units 20A, 20B, and 20C) connected to the outdoor unit 10. It is provided and configured. The indoor unit 10 and the outdoor unit 20 are connected by a refrigerant pipe 21 through which a refrigerant flows and electric wiring (not shown).

  The outdoor unit 10 includes a compressor 11 that compresses and sends out a refrigerant, a four-way valve 12 that switches a circulation direction of the refrigerant, an outdoor heat exchanger 13 that exchanges heat between the refrigerant and the outside air, and a throttling mechanism. The functioning electronic expansion valve 14 is a main component, and the muffler 15 disposed in the discharge side piping of the compressor 11 for the purpose of silencing and the suction of the compressor 11 for the purpose of gas-liquid separation of the refrigerant, etc. And an accumulator 16 disposed in the side pipe. In addition, the indoor unit 10 is provided with devices such as an outdoor fan, a receiver, a service valve, and a strainer (not shown), and sensors such as a temperature sensor.

The indoor unit 20 is configured such that devices such as an indoor heat exchanger and an indoor fan (not shown) are housed in a casing. The indoor unit 10 guides indoor air sucked by an indoor fan to the indoor heat exchanger, passes it through, and blows out the conditioned air heat-exchanged with the refrigerant supplied from the outdoor unit 10 described above into the room. It is configured as follows.
The three indoor unit units 20A, 20B, and 20C are connected to refrigerant pipes 21A, 21B, and 21C branched by a header 22 and a distributor 23 in the outdoor unit 10, respectively. In addition, in each refrigerant pipe 21A, 21B, 21C in the outdoor unit 10, an electronic expansion valve 14A, 14B, 14C that operates independently is provided between the outdoor heat exchanger 13 and the indoor units 20A, 20B, 20C. It is arranged in between.
In the multi-type air conditioner described above, a control unit (not shown) that performs various operation controls is provided in the outdoor unit 10 and each indoor unit 20.

Below, the effect | action of the multi-type air conditioning apparatus of the structure mentioned above is divided and demonstrated in each case at the time of heating operation and air_conditionaing | cooling operation.
Initially, the effect | action at the time of heating operation is demonstrated with the flow of the refrigerant | coolant shown with the broken-line arrow in the figure. The refrigerant that has been compressed into the high-temperature and high-pressure gas by the compressor 11 passes through the muffler 15 and the four-way valve 12 and is led from the refrigerant pipe 21 to the header 22. At this time, the refrigerant flow direction (cooling / heating operation switching) is selectively switched according to the set position of the four-way valve 12.

In this header 22, the refrigerant is branched into three refrigerant pipes 21A, 21B, and 21C, and sent to the indoor heat exchangers of the indoor unit 20A, 20B, and 20C provided in each flow path. When the indoor unit 20 is stopped, the electronic expansion valves 14A, 14B, 14C provided in the refrigerant pipes 21A, 21B, 21C are fully closed.
In the indoor unit 20 in operation, heat is given to the indoor air taken in from the suction grill by the indoor fan from the high-temperature and high-pressure gas refrigerant passing through the indoor heat exchanger. Thereby, warm air is blown out from the outlet of the indoor unit 20.
By such heat exchange, the high-temperature and high-pressure gaseous refrigerant is condensed and liquefied in the indoor heat exchanger, and becomes a high-temperature and high-pressure liquid refrigerant.

  The high-temperature and high-pressure liquid refrigerant is sent to the outdoor heat exchanger 13 of the outdoor unit 10 through the refrigerant pipe 21, but is squeezed and depressurized when passing through the electronic expansion valve 14 on the way. Thus, the low-temperature and low-pressure gas-liquid two-phase refrigerant is sent to the outdoor heat exchanger 13, and this gas-liquid two-phase refrigerant takes heat from the outside air when passing through the outdoor heat exchanger 13. Thus, the low-temperature and low-pressure gas-liquid two-phase refrigerant evaporates and becomes a low-temperature and low-pressure gas refrigerant. This gaseous refrigerant is sent again to the compressor 11 via the accumulator 16, and the process described above is repeated.

  Next, during the cooling operation, the refrigerant flows through the refrigerant circuit in the direction opposite to that during the heating operation described above by changing the setting position of the four-way valve 12. That is, the refrigerant made into a high-temperature and high-pressure gas in the compressor 11 passes through the refrigerant pipe 21 from the four-way valve 12 and is sent to the outdoor heat exchanger 13 as indicated by solid arrows in the figure, and heats the outdoor air. To condense and liquefy to become a high-temperature high-pressure liquid refrigerant. The high-temperature and high-pressure liquid refrigerant passes through the electronic expansion valve 14 to become a low-temperature and low-pressure gas-liquid two-phase refrigerant, and is sent again to the indoor heat exchanger of the indoor unit 20 through the refrigerant pipe 21. Here, the low-temperature and low-pressure gas-liquid two-phase refrigerant takes heat from the room air and cools the room air, and the refrigerant itself evaporates to become a low-temperature and low-pressure gas refrigerant.

This gaseous refrigerant is sent again to the compressor 11 via the accumulator 16, and the same process is repeated thereafter. Even during the cooling operation, the electronic expansion valve 14 connected to the indoor unit 20 that is stopped is fully closed.
Such an air conditioning operation is controlled by the cooperation of the control unit housed in the outdoor unit 10 and each indoor unit 20.

Now, in the above-described multi-type air conditioner, each indoor unit 20A, 20B, 20C can perform its own operation control. The operation control in this case means that, when either cooling operation or heating operation is selected, it is possible to operate / stop for each unit or to set an independent air conditioning temperature. .
Such a multi-type air conditioner is implemented when the cumulative operating time (T) of the compressor actual operation time accumulated on the basis of the start time of air-conditioning operation that satisfies a predetermined condition reaches a predetermined set time. The refrigerant accumulation protection control operation mode (hereinafter referred to as “protection control operation mode”) in which the compressor 11 is operated by fully opening all the electronic expansion valves 14 provided in the refrigerant circulation system path 21 of the indoor unit 20. Called).

This protection control operation mode is carried out in any air conditioning operation regardless of whether it is a cooling operation or a heating operation, and the accumulated time (T) accumulated from the start of the air conditioning operation satisfying a predetermined condition becomes a predetermined value. It starts when it is reached.
Here, a condition (predetermined condition) for starting accumulation of the accumulated time (T) is specifically shown.
The first condition is that the multi-type air conditioner is turned on to start the operation of the compressor 11. Since the operation start in this case is to start an air conditioning operation in which the refrigerant is compressed and sent out, either a cooling operation (including a dehumidifying operation) or a heating operation may be performed.
The second condition is when the multi-type air conditioner is in operation, and the previous protection control operation mode ends and normal air conditioning operation starts.

Starting from the time when either one of the two conditions (first or second condition) described above is satisfied, integration of the accumulated time (T) is started for the actual operation time of the compressor 11. The actual operation time of the compressor 11 is excluding the operation time when all the three indoor unit units 20A, 20B, and 20C are operated and the case where the rotation speed of the compressor 11 is 0 rps (that is, stopped). It is the driving time. In other words, the time during which at least one indoor unit 20 is in a stopped state and at least one other compressor 11 is in operation (the number of revolutions ≠ 0) is the actual operation time.
However, such accumulation of accumulated time (T) is performed when the operation state in which the stopped indoor unit 20 exists is switched to a state in which all indoor unit units are operated before the predetermined time elapses. The accumulated cumulative time (T) is reset.

Thus, the actual operation time of the compressor 11 is integrated, and when a predetermined cumulative time (T) has elapsed, the protection control operation mode is started. In this operation mode, all the electronic expansion valves 14 are fully opened, and the compressor 11 is operated. That is, all of the electronic expansion valve 14 that is disposed in the stopped refrigerant circulation path 21 and is fully closed and the electronic expansion valve 14 that is set to a predetermined throttle opening degree during the air conditioning operation are fully opened. In this state, the compressor 11 is operated to circulate the refrigerant.
Here, a specific control example of the protection control operation mode will be described with reference to FIG. The time chart of FIG. 2 shows (a) during cooling operation and (b) during heating operation, with the time as the horizontal axis in order from the top, the compressor rotation speed, the electronic expansion valve opening (operation unit), and the electronic expansion. The valve opening (stop unit) and the outdoor fan speed are shown.

First, the control during the cooling operation shown in FIG.
In this control, simultaneously with the start of control in the protective operation control mode, the compressor rotational speed is reduced to the compressor minimum rotational speed Rm. This compressor minimum rotation speed Rm is a value that allows the compressor 11 to rotate without stopping, and is determined by various conditions such as the specifications of the compressor 11.
Further, at the same time when the rotation speed reduction of the compressor 11 is completed, the opening degree of the electronic expansion valve 14 in the refrigerant circulation system (refrigerant pipe 21) in which the indoor unit 20 is in the air conditioning operation is fully opened. In the following description, the operating indoor unit 20 is referred to as an “operating unit”, and the stopped indoor unit 20 is referred to as a “stopping unit”.

  In this way, the compressor 11 is operated at the minimum rotational speed Rm, and the electronic expansion valve 14 of the operation unit 20 is fully opened to continue the operation for a predetermined time t1 (for example, about 60 seconds). Is also fully opened, and the rotational speed of the compressor 11 is increased to the refrigerant circulation minimum rotational speed R1. This minimum refrigerant circulation speed R1 is the minimum necessary value that allows the refrigerant to circulate through all the refrigerant circulation paths by fully opening the electronic expansion valve 14. In other words, the refrigerant circulation minimum rotation speed R1 is the minimum rotation speed capable of generating a flow sufficient to collect the refrigerant and lubricating oil accumulated in the stop unit and the refrigerant circulation path.

As a result, in the multi-type air conditioner, all the electronic expansion valves 14 are fully opened and the compressor 11 is operated at the refrigerant circulation minimum rotation speed R1, so that the refrigerant circulation path including all the indoor unit units 20 is refrigerant. Will circulate. Such circulation of the refrigerant is continued for a predetermined time t2 (for example, about 120 seconds). Such refrigerant circulation makes it possible in particular to collect the refrigerant and lubricating oil that have accumulated in the stop unit.
When the operation for recovering the accumulated refrigerant and lubricating oil (hereinafter referred to as “recovery operation”) is completed in this way, the rotational speed of the compressor 11 is returned to the original state (the state before the start of the protection control operation mode).

On the other hand, the opening degree of the electronic expansion valve 14 is returned to the original state as follows before the predetermined time t2 elapses.
The electronic expansion valve 14 of the stop unit is returned to the fully closed state in the original state before the recovery operation for the predetermined time t2 is completed. That is, the electronic expansion valve 14 of the stop unit is in a state before the start of the protection control operation mode after the recovery operation time of t3 shorter than the predetermined time t2 elapses before the compressor 11 is returned to the original rotation speed upon completion of the recovery operation. It is returned to a certain full closure.
Also, the electronic expansion valve 14 of the operation unit operates at the same time as the electronic expansion valve 14 of the stop unit is fully closed, and is returned to the original opening degree before the collection operation for the predetermined time t2 is completed. That is, before the recovery operation for the predetermined time t2 is completed and the rotation speed of the compressor 11 is restored, all the electronic expansion valves 14 are returned to the original state.

Further, the control during the heating operation shown in FIG. 2B is also performed in the same manner as during the cooling operation described above, and thus detailed description thereof is omitted here.
During the air conditioning operation, the outdoor fan is operated to increase the rotational speed during the above-described recovery operation, and the predetermined time after the recovery operation is set as a defrost operation prohibited time zone.

  By implementing the refrigerant accumulation protection control operation mode described above, the refrigerant and the lubricating oil are passed through the refrigerant circulation system path including all the indoor unit 20 in any of the air conditioning operation of the cooling operation and the heating operation. Since the refrigerant flows, the refrigerant and lubricating oil accumulated in the refrigerant circulation path including the refrigerant and lubricating oil staying in the stopped indoor unit 20 flow out by this flow and return to the compressor 11. Therefore, it becomes possible to reliably collect the refrigerant and the lubricating oil from the system. Even in the protection control operation mode during the heating operation, the electronic expansion valve 14 is fully opened, so that the flow is not interrupted and the refrigerant and lubricating oil are not accumulated.

In the above-described protection control operation mode, the time for which all the indoor units 20 are operated is not included in the accumulated time (T) because there is no fear of accumulation, and the accumulated time is not included in the total operation. Since the resetting is performed, the number of times that the protection operation control mode is executed can be minimized. For this reason, it can suppress that it becomes a severe operating condition for the compressor 11 by the fall of the air-conditioning feeling by implementation of protection operation control mode, and deviating from an appropriate operating point.

  Further, in the above-described protection control operation mode, since the electronic expansion valve 14 is fully opened after the operating speed of the compressor 11 is once reduced to the minimum, the circulation amount of the refrigerant is reduced to the necessary minimum and the flow noise is reduced. It can be suppressed. Such a decrease in the amount of refrigerant circulation is also effective in preventing a liquid back that flows into the compressor 11 in a liquid phase when the electronic expansion valve 14 is fully opened.

  Further, in the above-described protection control mode, the predetermined delay time t4 is provided before the electronic expansion valve 14 installed in the refrigerant circulation system path where the indoor unit 20 is stopped is fully opened. The electronic expansion valve 14 can be fully opened in a state where the number of rotations 11 is reduced and the pressure ratio is reduced. For this reason, since the noise of the refrigerant flow noise can be reduced, the refrigerant flow noise generated from the stop unit 20 without operation noise because the operation is originally stopped is reduced, and the unnatural feeling of unnatural driving noise given to the user is reduced. Can be relaxed.

  Further, at the end of the above-described protection control mode, the opening degree of the electronic expansion valve 14 is returned before the start of the protection control in the order of the stop unit and the operation unit, and then the rotation speed of the compressor 1 is returned before the start of the protection control. Therefore, in the stop unit, it is possible to prevent the operation noise due to the refrigerant flow noise and to prevent the liquid back in which the liquid refrigerant that is not throttled by the electronic expansion valve 14 flows into the compressor 11.

As described above, in the multi-type air conditioner of the present invention, in the protection control mode for collecting the refrigerant and the lubricating oil, the control that clearly classifies the roles of the operation unit and the stop unit is performed, and the heating operation is performed. At any time during cooling or cooling operation, it is possible to reliably recover the refrigerant and the lubricating oil while minimizing the deterioration of the air conditioning feeling and severe operation of the compressor 11.
In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably.

It is a lineblock diagram showing one embodiment of a multi type air harmony device concerning the present invention. It is a time chart which shows control of a compressor rotation speed, an electronic expansion valve opening degree, and an outdoor fan about the refrigerant | coolant accumulation protection control operation mode of this invention, (a) is at the time of cooling operation, (b) is at the time of heating operation. is there.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Outdoor unit 11 Compressor 12 Four-way valve 13 Outdoor heat exchanger 14 Electronic expansion valve 20 Indoor unit 21 Refrigerant piping

Claims (4)

In a multi-type air conditioner comprising an outdoor unit and a plurality of indoor unit units that are connected to the indoor unit unit and enable independent operation control,
The refrigerant circulation path of the indoor unit is implemented when the cumulative time (T) of the compressor actual operation time accumulated on the basis of the start time of the air conditioning operation that satisfies the predetermined condition reaches a predetermined set time. A multi-type air conditioner having a refrigerant accumulation protection control operation mode in which the compressor is operated by fully opening all of the electronic expansion valves provided in each.   2. The multi-type air conditioner according to claim 1, wherein in the refrigerant accumulation protection control operation mode, the electronic expansion valve is fully opened after the operation rotational speed of the compressor is once reduced to a minimum.   The refrigerant accumulation protection control mode is characterized in that a predetermined delay time is provided before the electronic expansion valve installed in the refrigerant circulation system path where the indoor unit is stopped is fully opened. 2. The multi-type air conditioner according to 2.   The end of the refrigerant accumulation protection control mode is completed by returning the opening of the electronic expansion valve before the start of protection control and then returning the rotational speed of the compressor before the start of protection control. Item 4. The multi-type air conditioner according to Item 2 or 3.

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