JP2009243843A - Multi-type air conditioner and its operation control method - Google Patents

Abstract

An object of the present invention is to provide a multi-type air conditioner capable of preventing a communication failure due to forgetting to open or close a valve of an oil equalizing pipe or a valve failure and preventing a compressor trouble due to lack of lubricating oil, and an operation control method thereof. And
In a multi-type heat pump type air conditioner including a plurality of outdoor units, during the trial operation, one of the outdoor units is operated by heating, and the pressure sensor 32 of each outdoor unit 2 causes the suction side of the accumulator 10 to operate. The open / close valve 31 of the oil equalizing pipe 30 is checked for opening / closing by comparing the refrigerant pressure on the low pressure side. Thereby, when the on-off valve 31 is not open, it is detected reliably.
[Selection] Figure 1

Description

  The present invention relates to a multi-type air conditioner and an operation control method thereof.

  Some air conditioners for buildings that include a plurality of indoor units include a plurality of outdoor units.

  In the air conditioner, the lubricating oil of the compressor provided in the outdoor unit flows out in the form of mist into the gas refrigerant discharged from the compressor to the outside. The lubricating oil that has flowed out stays in the piping, the heat exchanger of the indoor unit, or the like. For this reason, oil return control is performed to return the lubricating oil staying in the piping or the like into the compressor.

However, in an air conditioner equipped with multiple outdoor units, the amount of oil that returns to the compressor during oil return control due to differences in the operating state and load of each outdoor unit, branching of piping to the outdoor unit, piping length, etc. In some cases, poor lubrication, seizure, or the like may occur in the compressor of the outdoor unit with a small oil return amount.
Also, during normal operation, the difference in the amount of oil in the oil sump of the compressor will be less than the required amount due to differences in the operating conditions and loads of each outdoor unit, branching of piping to the outdoor unit and piping length, etc. Otherwise, poor lubrication or seizure may occur.
In view of this, the oil amount of each compressor is communicated with an oil equalizing pipe between a plurality of outdoor units to equalize the amount of oil (see, for example, Patent Document 1).
JP-A-10-238881

However, the conventional techniques have the following problems.
In order to block communication with other outdoor units during installation and maintenance of the outdoor unit, the oil equalizing pipe is provided with an on-off valve in the vicinity of each outdoor unit. Normally, after the installation and maintenance work is completed, the on-off valve is opened and communicated with the compressor of another outdoor unit through the oil equalizing pipe. However, the on-off valve may remain closed due to forgetting work or the like.
Moreover, when the on-off valve is out of order, a situation may be considered in which the operator does not actually open it even though he intends to open it.
Nevertheless, since the air conditioner can be operated, the oil equalizing pipe does not function if the on-off valve is kept closed, which may cause a compressor trouble.

  The present invention has been made in view of such circumstances, and prevents the occurrence of compressor trouble due to lack of lubricating oil by preventing forgetting to open the valve of the oil equalizing pipe and poor communication at the time of failure. An object of the present invention is to provide a type air conditioner and an operation control method thereof.

In order to solve the above problems, the multi-type air conditioner of the present invention employs the following means.
That is, a multi-type air conditioner including a plurality of outdoor units and a plurality of indoor units, each having an oil equalizing pipe that communicates an oil sump of a compressor of the plurality of outdoor units with each other, An open / close valve provided in the vicinity of the outdoor unit, a pressure sensor for detecting the refrigerant pressure on the suction side of the compressor in each of the plurality of outdoor units, and operating only one outdoor unit among the plurality of outdoor units And a controller that detects the presence or absence of a closed on-off valve by comparing refrigerant pressure detected by a pressure sensor between a plurality of outdoor units.

  As described above, when only one outdoor unit among a plurality of outdoor units is operated in the heating operation, the refrigerant pressure detected by the pressure sensor is compared between the plurality of outdoor units. If they are all open, the refrigerant pressure detected by the pressure sensor between the plurality of outdoor units is substantially equal. On the other hand, when any of the opening / closing valves of the oil equalizing pipe is closed, the refrigerant pressure detected by the pressure sensor is greatly different between the plurality of outdoor units. Thereby, it is possible to detect the presence or absence of the open / close valve in the closed state.

  For this reason, in the multi-type air conditioner of the present invention, the controller determines that there is a closed on-off valve when the difference in refrigerant pressure between the plurality of outdoor units exceeds a predetermined threshold. Features.

  In the multi-type air conditioner of the present invention, the control unit compares refrigerant pressures on the suction side of the compressors of a plurality of outdoor units during a trial operation performed after the installation or maintenance of the multi-type air conditioner. It is characterized by.

  As a result, when there is an open / close valve in the closed state at the trial operation stage, this can be detected, so that trouble or the like can be prevented during normal operation after the trial operation.

  The present invention also includes a plurality of outdoor units and a plurality of indoor units, and the oil sumps of the compressors of the plurality of outdoor units are communicated with each other by an oil equalizing pipe. An operation control method for a multi-type air conditioner provided with an on-off valve in the vicinity thereof, in each of a plurality of outdoor units, a pressure detection process for detecting refrigerant pressure on the suction side of the compressor, and between a plurality of outdoor units And a pressure comparison process for detecting the presence / absence of a closed on-off valve by comparing the refrigerant pressure detected by the pressure sensor. You can also.

  The operation control method for a multi-type air conditioner according to the present invention is characterized in that the pressure detection process and the pressure comparison process are executed during a test operation that is performed after the installation of the multi-type air conditioner or after the completion of maintenance.

  Furthermore, the operation control method for a multi-type air conditioner according to the present invention is characterized in that the pressure detection process and the pressure comparison process are performed during a heating operation in which any one outdoor unit is operated.

  The present invention may also be a computer program that causes the control unit of the multi-type air conditioner to execute the pressure detection process and the pressure comparison process in the operation control method of the multi-type air conditioner as described above.

  According to the present invention, in a state where only one of the plurality of outdoor units is operated in the heating operation, the refrigerant pressure detected by the pressure sensor is compared between the plurality of outdoor units, and the closed state The presence / absence of the on / off valve can be detected. As a result, when there is an open / close valve in the closed state, the detection result is received, and the open / close valve is actually opened or replaced when a failure occurs. In this way, it is possible to prevent the occurrence of troubles in the compressor due to lack of lubricating oil due to forgetting to open the open / close valve of the oil equalizing pipe or poor communication due to valve failure.

Embodiments according to the present invention will be described below with reference to the drawings.
FIG. 1 shows a refrigerant circuit diagram of a multi-type heat pump air conditioner 1 according to the present embodiment.
The multi-type heat pump air conditioner 1 is configured such that a plurality of indoor units (not shown) are connected in parallel to a plurality of, for example, two outdoor units (outdoor units) 2. In the present embodiment, the number of connected outdoor units and indoor units is not particularly limited.

  Each outdoor unit 2 includes a compressor 5, a discharge pipe 4 </ b> A connected to the compressor 5, a four-way switching valve 7 connected to the first port 7 </ b> A, and a refrigerant pipe 4 </ b> B to a second port 7 </ b> B of the four-way switching valve 7. Two outdoor heat exchangers 8A and 8B connected through the refrigerant, a refrigerant liquid pipe 4C extending from the outdoor heat exchangers 8A and 8B to the indoor unit (not shown) side, and the four-way switching valve 7 The refrigerant gas pipe 4D extending from the 3 port 7C to the indoor unit (not shown) side is connected to the fourth port 7D of the four-way switching valve 7 via the suction pipe 4E, and the suction pipe 4F to the compressor 5 Are connected via the discharge pipes 4A to 4F as described above, and constitute an outdoor refrigerant pipe circuit.

  The outdoor heat exchangers 8A and 8B are provided with expansion valves 20A and 20B, respectively. In this embodiment, the two outdoor heat exchangers 8A and 8B are provided. However, only one outdoor heat exchanger may be provided, and no accumulator may be provided.

  The refrigerant liquid pipe 4C is provided with a receiver 12 for storing liquid refrigerant and a double pipe heat exchanger 13. The double pipe heat exchanger 13 divides a part of the liquid refrigerant from the refrigerant liquid pipe 4C at the outlet of the receiver 12 and leads it to the inner pipe 13A of the double pipe heat exchanger 13, and the diversion pipe 14 And an electronic expansion valve 15 provided in the apparatus. The double pipe heat exchanger 13 depressurizes the refrigerant divided into the branch pipe 14 by the electronic expansion valve 15 and evaporates the refrigerant in the inner pipe 13A of the double pipe heat exchanger 13, thereby double The refrigerant main stream flowing on the outer pipe side (refrigerant liquid pipe 4C) of the pipe heat exchanger 13 is cooled to give supercooling. The refrigerant evaporated in the inner pipe 13 </ b> A of the double pipe heat exchanger 13 is sent to the accumulator 10 through the pipe 16.

  Here, between the plurality of outdoor units 2, oil leveling pipes 30 are provided to communicate oil reservoirs of the compressors 5 of the outdoor units 2. The oil equalizing pipe 30 is provided with on-off valves 31 in the vicinity of the compressors 5 on both sides.

Next, the effect | action of the multi-type heat pump type air conditioner 1 concerning this embodiment is demonstrated. Note that the operation and operation of the multi-type heat pump air conditioner 1 described below is performed by a control unit (not shown) in accordance with the selection of an operation mode such as cooling operation or heating operation by the user. It is automatically performed by controlling each part of the machine 1.
First, the cooling operation will be described. At the time of cooling, in each outdoor unit 2, the four-way switching valve 7 is switched to a state in which the first port 7A and the second port 7B, and the third port 7C and the fourth port 7D are in communication with each other. Thereby, the high-temperature and high-pressure refrigerant gas compressed by the compressor 5 flows into the outdoor heat exchangers 8A and 8B through the discharge pipe 4A, the four-way switching valve 7, and the refrigerant pipe 4B. This refrigerant exchanges heat with the outside air in the outdoor heat exchangers 8A and 8B, dissipates heat to the outside air, and is condensed and liquefied. The liquefied refrigerant flows in one direction in the refrigerant liquid pipe 4 </ b> C and flows into the receiver 12.

The refrigerant flowing out from the receiver 12 is cooled while passing through the double-pipe heat exchanger 13, and is further subcooled.
The refrigerant evaporated in the inner pipe 13A of the double pipe heat exchanger 13 is sent into the accumulator 10 through the pipe 16 from the outlet.

On the other hand, the refrigerant that has been supercooled in the double pipe heat exchanger 13 flows to the indoor unit (not shown) through the refrigerant liquid pipe 4C. At this time, the refrigerant sent out through the refrigerant liquid pipes 4C of the plurality of outdoor units 2 merges and is sent to the indoor unit (not shown).
The refrigerant that has flown into each indoor unit (not shown) flows into the indoor heat exchanger (not shown) of the indoor unit and is heat-exchanged with the indoor air circulated to the indoor heat exchanger to cool the indoor air. By doing this, it is subjected to cooling.
The refrigerant evaporated by cooling the room air in the indoor heat exchanger (not shown) returns to the outdoor unit 2 again through the refrigerant gas pipe 4D, and the four-way switching valve 7, the suction pipe 4E, the accumulator 10, and the suction pipe. It is sucked into the compressor 5 through 4F. The cooling operation is performed by repeating this refrigerant circulation cycle.

  Subsequently, the heating operation will be described. During heating, in each outdoor unit 2, the four-way switching valve 7 is switched to a state in which the first port 7A and the third port 7C, and the second port 7B and the fourth port 7D communicate with each other. Thereby, the high-temperature and high-pressure refrigerant gas compressed by the compressor 5 flows into each indoor unit (not shown) through the discharge pipe 4A, the four-way switching valve 7, and the refrigerant gas pipe 4D. The refrigerant flowing into the indoor unit (not shown) is heat-exchanged with indoor air circulated by a fan (not shown) in an indoor heat exchanger (not shown) to heat the indoor air. This room air is used for heating.

The refrigerant condensed and liquefied by radiating heat to the indoor air with an indoor heat exchanger (not shown) returns to the outdoor unit 2 again through the refrigerant liquid pipe 4C. The refrigerant that has returned to the outdoor unit 2 flows in one direction in the refrigerant liquid pipe 4 </ b> C and flows into the receiver 12.
The refrigerant that flows out of the receiver 12 flows into the outdoor heat exchangers 8A and 8B, absorbs heat from the outside air, and is evaporated. Thereafter, the refrigerant is sucked into the compressor 5 through the refrigerant pipe 4B, the four-way switching valve 7, the suction pipe 4E, the accumulator 10, and the suction pipe 4F. The heating operation is performed by repeating this refrigerant circulation cycle.

In the outdoor unit 2 as described above, oil return control is performed to return the lubricating oil that has flowed out of the compressor 5 and stayed in the piping, the interior of the indoor heat exchanger, or the like into the compressor 5. However, in an air conditioner having a plurality of outdoor units, the oil that returns to the compressor 5 at the time of oil return control due to differences in the operating state and load of each outdoor unit, branching of piping to the outdoor unit, piping length, etc. There is a difference in the amount, and the compressor 5 of the outdoor unit with a small amount of oil return may cause poor lubrication or seizure.
In addition, even during normal cooling and heating operations, differences in the amount of oil in the oil sump of the compressor 5 occur due to differences in the operating state and load of each outdoor unit, branching of piping to the outdoor unit, piping length, and the like. Less than the required amount may cause poor lubrication or seizure.

  At this time, between the plurality of outdoor units 2, the compressors 5 communicate with each other through the oil equalizing pipe 30, so that the amount of lubricating oil returned to the oil sump of the compressor 5 can be made uniform.

In the normal operation such as the cooling / heating operation or the oil return operation as described above, the on-off valve 31 of the oil equalization 20 is open, but as described above, the outdoor unit 2 At the time of installation or maintenance, there is a possibility that the operator forgets to open the on-off valve 31, and there is a possibility that the on-off valve 31 will not open due to a failure.
Therefore, in the present embodiment, a process for confirming whether or not all the on-off valves 31 are open is automatically controlled by a control unit (not shown) at the time of a trial operation performed after the installation or maintenance of the outdoor unit 2. Execute.

  For this reason, each outdoor unit 2 is provided with a pressure sensor 32 for detecting the refrigerant pressure on the low pressure side in the suction pipe 4 </ b> E of the accumulator 10.

  And in the control part which is not shown in figure, in the process of a series of processes which test-operate the multi-type heat pump type air conditioner 1 based on a predetermined program, one outdoor unit 2 among several outdoor units 2 is shown. Only the heating operation is performed (the other outdoor units 2 are not operated), and the opening / closing check process of the opening / closing valve 31 is performed.

For this purpose, the detection values of the pressure sensors 32 of the outdoor units 2 are compared in the heating operation state as described above.
As shown in FIG. 2, among the plurality of outdoor units 2, in the state where only one outdoor unit 2 is operated, if both the open / close valves 31 of the oil equalizing pipe 30 are open, the thick line in FIG. As shown, the pressure of the oil sump of the compressor 5 of the outdoor unit 2 that has been operated propagates to the oil sump and the low pressure system of the compressor 5 of the other outdoor unit 2. On the other hand, as shown in FIG. 3, when the open / close valve 31 of the oil equalizing pipe 30 is open only on one of the outdoor units 2, the oil of the compressor 5 of the operated outdoor unit 2 is shown in FIG. The pressure of the reservoir is shut off by the closed on-off valve 31 and does not propagate to the oil reservoir and the low pressure system of the compressor 5 of the other outdoor unit 2.
For this reason, if the detection value of the pressure sensor 32 of each outdoor unit 2 is equal as a result of the comparison, it can be determined that both the open / close valves 31 of the oil equalizing pipe 30 are open. If the detected values of the pressure sensors 32 of the outdoor units 2 are not equal, it can be determined that one of the on-off valves 31 of the oil equalizing pipe 30 is closed.

  Here, it is determined whether or not the detected values of the pressure sensors 32 of the outdoor units 2 are equal. In consideration of variations between the outdoor units 2 and pressure loss, the pressure of one outdoor unit 2 is determined. It is preferable to determine whether the difference between the detection value of the sensor 32 and the detection value of the pressure sensor 32 of the other outdoor unit 2 is equal to or less than a predetermined threshold value. In this case, in the outdoor unit 2 on the side where the open / close valve 31 of the oil equalizing pipe 30 is closed, the refrigerant pressure on the low pressure side in the suction pipe 4E of the accumulator 10 is substantially equal to the saturation pressure at the outside temperature, and the open / close valve 31 is closed. Since there is a difference in the refrigerant pressure on the other side, the threshold used for the above determination can be set appropriately.

  The control unit preferably outputs the determination result to the operation panel of the heat pump air conditioner 1 by turning on an indicator lamp, generating a buzzer sound, or the like.

As described above, according to the multi-type heat pump air conditioner 1 according to the present embodiment, the following operational effects can be obtained.
During the trial operation, the pressure sensor 32 of each outdoor unit 2 compares the low-pressure refrigerant pressure on the suction side of the accumulator 10 to check the opening / closing of the open / close valve 31 of the oil equalizing pipe 30. As a result, if the on-off valve 31 is not open, it can be detected, so that, based on the result, the on-off valve is actually opened or replaced when a failure occurs. In this way, since the opening / closing of the on-off valve 31 can be surely known, forgetting to open the on-off valve 31 of the oil equalizing pipe 30 or poor communication due to a failure of the on-off valve can be prevented, and troubles in the compressor 5 due to lack of lubricating oil can be prevented. It becomes possible to prevent. In addition, since the pressure sensor 32 is usually provided for air conditioning control conventionally, only a computer program for processing is necessary to obtain such an effect. Therefore, the above effect can be obtained at low cost. In addition, the existing multi-type heat pump 1 can achieve the effects of the present invention only by replacing the computer program.

In each embodiment described above, each part of the multi-type heat pump type air conditioner 1 has been described. However, the present invention is not limited to this, and for example, an indoor unit (not shown) or the like adopts any configuration. May be.
It is also possible to improve the cooling and heating capacity and efficiency, and to appropriately combine other configurations.

It is a figure which shows the structure of the outdoor unit of the multi-type heat pump type air conditioner concerning embodiment of this invention. It is a figure which shows the propagation of the pressure by an oil equalizing pipe in the state which the on-off valve of both the outdoor units opened. It is a figure which shows the propagation of the pressure by an oil equalizing pipe in the state where the on-off valve of one outdoor unit was closed.

Explanation of symbols

1 Multi-type heat pump air conditioner 2 Outdoor unit (outdoor unit)
4A Discharge piping (outdoor cooling piping)
4B Refrigerant piping (outdoor cooling piping)
4C Refrigerant liquid pipe (outdoor cooling piping)
4D refrigerant gas pipe (outdoor cooling pipe)
4E Suction piping (outdoor cooling piping)
4F Suction piping (outdoor cooling piping)
5 Compressor 7 Four-way selector valve 8A, 8B Outdoor heat exchanger 10 Accumulator 12 Receiver 13 Double pipe heat exchanger 20A, 20B Expansion valve 30 Oil equalizing pipe 31 On-off valve 32 Pressure sensor

Claims (6)

A multi-type air conditioner comprising a plurality of outdoor units and a plurality of indoor units,
An oil equalizing pipe that communicates oil reservoirs of the compressors of the plurality of outdoor units with each other;
An on-off valve provided in the vicinity of each outdoor unit in the oil equalizing pipe;
In each of the plurality of outdoor units, a pressure sensor that detects a refrigerant pressure on the suction side of the compressor;
In a state where only one of the plurality of outdoor units is operated, the refrigerant pressure detected by the pressure sensor is compared between the plurality of outdoor units, so that the open / close valve in the closed state A control unit for detecting the presence or absence of
A multi-type air conditioner comprising:   The said control part determines with the said on-off valve of a closed state existing when the difference of the said refrigerant | coolant pressure between the said some outdoor units exceeds the predetermined threshold value. Multi-type air conditioner.   The said control part compares the said refrigerant | coolant pressure in the suction side of the said compressor of the said some outdoor unit at the time of the test operation performed after installation or the maintenance of the said multi-type air conditioner. Or the multi type air conditioner of 2. A plurality of outdoor units and a plurality of indoor units are provided, and the oil sumps of the compressors of the plurality of outdoor units are communicated with each other by oil leveling pipes, and the oil leveling pipes are opened and closed in the vicinity of the outdoor units. An operation control method for a multi-type air conditioner provided with a valve,
In each of the plurality of outdoor units, a pressure detection process for detecting a refrigerant pressure on the suction side of the compressor;
A pressure comparison process for detecting the presence or absence of the on-off valve in a closed state by comparing the refrigerant pressure detected by the pressure sensor between the plurality of outdoor units;
An operation control method for a multi-type air conditioner, comprising:   5. The operation control method for a multi-type air conditioner according to claim 4, wherein the pressure detection process and the pressure comparison process are executed during a test operation performed after the installation of the multi-type air conditioner or after completion of the maintenance. .   The operation control method for a multi-type air conditioner according to claim 4 or 5, wherein the pressure detection process and the pressure comparison process are performed during heating operation.

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