CN110779112A - Air conditioning device - Google Patents

Abstract

The present invention provides an air-conditioning apparatus capable of securing oil in the operating outdoor unit and preventing thermal sticking due to depletion of the oil in the operating compressor when the cooling operation is performed using one outdoor unit. The GHP control unit (100) or the EHP control unit (101) performs cooling operation using only one GHP outdoor unit (2) of the GHP outdoor unit (2) and the EHP outdoor unit (3), and the other EHP outdoor units ( 3) In the case of stop, based on the detection value of the GHP oil level sensor (106) from the GHP outdoor unit (2) in operation, it is determined whether the oil level is lower than a certain level, and if it is determined that the oil level is lower than a certain level Next, control is performed so as to open the oil return valve (34) of the GHP outdoor unit (2) in operation.

Description

Air conditioner

technical field

The present invention relates to an air conditioner, and more particularly, to an air conditioner using a GHP outdoor unit and an EHP outdoor unit in combination.

Background technique

In general, there are known air conditioning apparatuses that use an outdoor unit equipped with a compressor driven by a gas engine or the like and an outdoor unit equipped with a compressor driven by electricity to perform air conditioning by an indoor unit. adjust.

As such an air-conditioning apparatus, the prior art discloses, for example, an air-conditioning apparatus including: a second outdoor unit having a high-capacity compressor, a four-way valve, and an outdoor heat exchanger; and a low-capacity air conditioner The compressor, the four-way valve, and the first outdoor unit of the outdoor heat exchanger; the indoor unit connected to these outdoor units by one refrigerant system (for example, refer to Patent Document 1).

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2017-150687

SUMMARY OF THE INVENTION

The problem to be solved by the invention

Here, in the conventional technology, an oil return pipe connecting the discharge side and the suction side of the compressor is provided in the outdoor unit, and an oil return valve for adjusting the flow rate of the returned oil is provided in the oil return pipe. Then, by opening the oil return valve, a part of the oil on the discharge side of the compressor is sent to the suction side of the compressor through the oil return pipe due to the pressure difference.

However, in the above-mentioned conventional air-conditioning apparatus, when the cooling operation is performed by one outdoor unit and the other outdoor unit is stopped, the cooling operation is applied from the outdoor unit in operation to the discharge side of the oil return valve of the outdoor unit in stoppage. At high pressure, the oil return valve is opened, so there is a problem that refrigerant and oil are accumulated in the stopped outdoor unit.

In this way, if the refrigerant and oil are accumulated in the stopped outdoor unit, the oil level of the compressor in operation cannot be ensured suddenly, and there is a problem of failure due to thermal sticking.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a device that can secure the oil of the outdoor unit in operation when the cooling operation is performed by one outdoor unit, and can prevent oil from the compressor in operation Depletion of hot sticky air conditioners.

methods for solving problems

In order to achieve the above object, the present invention provides an air conditioner in which a plurality of outdoor units are connected to indoor units via inter-unit piping, each of the outdoor units is operated, and the indoor unit is used to perform indoor air conditioning, It is characterized by comprising: an oil return pipe provided on the discharge side of the compressor of the outdoor unit for returning oil to the suction side; an oil return valve provided in the middle part of the oil return pipe; and oil for detecting the oil level of the outdoor unit a position sensor; and a control unit for controlling the outdoor unit, the control unit performing a cooling operation using only one of the outdoor units and the other outdoor units are stopped, based on the information from the outdoor unit in operation The detection value of the above-mentioned oil level sensor determines whether the oil level is lower than a certain level, and when it is determined that the oil level is lower than a certain level, control is performed to open the above-mentioned oil return valve of the above-mentioned outdoor unit in operation.

Thereby, high pressure is not applied to the discharge side of the oil return valve of the stopped outdoor unit due to the opening of the oil return valve, and it is possible to prevent the refrigerant and oil from accumulating in the stopped outdoor unit. In addition, the refrigerant and oil stored in the outdoor unit that is being stopped can be sent to the suction side of the compressor of the outdoor unit that is in the cooling operation.

effect of invention

According to the air conditioner of the present invention, the opening of the oil return valve does not apply high pressure to the discharge side of the oil return valve of the stopped outdoor unit, and can prevent the refrigerant and oil from accumulating in the stopped outdoor unit. In addition, the refrigerant and oil stored in the outdoor unit that is being stopped can be sent to the suction side of the compressor of the outdoor unit that is in the cooling operation. As a result, the oil for the compressor in the cooling operation can be sufficiently secured, and the hot sticking can be prevented.

Description of drawings

FIG. 1 is a configuration diagram of an air-conditioning apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control structure of the present embodiment.

FIG. 3 is a flowchart showing the operation of the present embodiment.

Description of reference numerals

1 Air conditioner

2 GHP Outdoor Units

3 EHP Outdoor Units

4 indoor units

12 Gas engine

1 GHP compressor

15 Oil separator

17, 65 Outdoor heat exchanger

30, 73 Oil return piping

34, 76 Oil return valve

40 Indoor heat exchanger

62 EHP compressors

100 GHP Control Section

101 EHP Control Department

102 Indoor Control Department

106 GHP oil level sensor

107 EHP oil level sensor

110 Controller

111 Controller control section

Detailed ways

A first invention is an air-conditioning apparatus in which a plurality of outdoor units are connected to indoor units via inter-unit piping, and each of the outdoor units is operated to perform indoor air-conditioning using the indoor unit, and the air-conditioning apparatus is characterized by comprising: : an oil return pipe provided on the discharge side of the compressor of the outdoor unit for returning oil to the suction side; an oil return valve provided in the middle of the oil return pipe; an oil level sensor for detecting the oil level of the outdoor unit; and A control unit for controlling the outdoor unit, wherein the control unit is based on the oil level from the operating outdoor unit when the cooling operation is performed by only one of the outdoor units and the other outdoor units are stopped Based on the detection value of the sensor, it is determined whether the oil level is lower than a certain level, and when it is determined that the oil level is lower than a certain level, control is performed to open the oil return valve of the outdoor unit in operation.

Thereby, high pressure is not applied to the discharge side of the oil return valve of the stopped outdoor unit due to the opening of the oil return valve, and it is possible to prevent the refrigerant and oil from accumulating in the stopped outdoor unit. In addition, the refrigerant and oil stored in the outdoor unit that is being stopped can be sent to the suction side of the compressor of the outdoor unit that is in the cooling operation. As a result, the oil for the compressor in the cooling operation can be sufficiently secured, and the hot sticking can be prevented.

In the second aspect of the invention, the control unit is configured such that, when two or more outdoor units are operating, the oil level based on the detection value from the oil level sensor is higher than a certain level, or a protection control operation is performed. In the state, the control to open the above-mentioned oil return valve is ended.

Thereby, when the oil of the compressor can be secured, the supply of unnecessary oil can be stopped by ending the control to open the oil return valve.

In the air conditioner of the third invention, the plurality of outdoor units are a GHP outdoor unit including a GHP compressor driven by an engine, and an EHP outdoor unit including an EHP compressor driven by a commercial power supply.

As a result, a plurality of outdoor units can be constituted by the GHP outdoor unit and the EHP outdoor unit, and when the cooling operation is performed by either the GHP outdoor unit or the EHP outdoor unit, the discharge of the oil return valve of the outdoor unit being stopped can be performed. High pressure is not applied to the side, and it is possible to prevent refrigerant and oil from accumulating in the stopped outdoor unit. In addition, the refrigerant and oil stored in the outdoor unit that is being stopped can be sent to the suction side of the compressor of the outdoor unit that is in the cooling operation. As a result, the oil for the compressor in the cooling operation can be sufficiently secured, and the hot sticking can be prevented.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of an air-conditioning apparatus according to the present invention.

As shown in FIG. 1 , the air-conditioning apparatus 1 includes: a GHP outdoor unit 2 (second outdoor unit) having a GHP compressor 13 driven by a gas engine as a compressor with high performance; an EHP outdoor unit 3 (first outdoor unit) an outdoor unit) having an EHP compressor 62 driven by a commercial power supply as a compressor of lower capacity; and a plurality of indoor units 4 . The GHP outdoor unit 2 , the EHP outdoor unit 3 , and each indoor unit 4 are connected via the inter-unit piping 5 and the oil balance piping 6 , thereby constituting a refrigeration cycle for performing an air-conditioning operation.

The GHP outdoor unit 2 includes two external connection valves 10 a and 10 b for connection to the external inter-unit piping 5 , and an oil connection valve 11 for connection to the oil balance piping 6 .

The GHP outdoor unit 2 is provided with a gas engine 12 as an engine, and a GHP compressor 13 that compresses the refrigerant by the driving force of the gas engine 12 . The GHP compressor 13 is constituted by a first GHP compressor 13a and a second GHP compressor 13b arranged in parallel.

The gas engine 12 is configured to generate driving force by burning a mixture of fuel such as gas supplied through a fuel regulating valve (not shown) and air supplied through a throttle valve (not shown).

A drive belt 14 is spanned between the output shaft of the gas engine 12 and the driven shaft of the GHP compressor 13 , and the GHP compressor 13 is driven by transmitting the driving force of the gas engine 12 via the drive belt 14 .

An oil separator 15 , a four-way valve 16 , and two outdoor heat exchangers 17 and 17 are sequentially connected to the discharge side of the GHP compressor 13 . An outdoor fan 18 for exchanging heat between the outdoor heat exchanger 17 and outside air is provided near the outdoor heat exchanger 17 .

Moreover, the other external connection valve 10b is connected to the refrigerant piping 20 which is connected to the suction side of the GHP compressor 13 via the four-way valve 16 and the accumulator 19 on the way.

An electric valve 24 and a check valve 25 are connected in parallel to a midway portion of the refrigerant piping 20 , and a liquid pipe 22 connected to the inflow side of the accumulator 19 is connected to the refrigerant piping 20 . A dry core 39 is provided between the outdoor heat exchanger 17 and the external connection valve 10a.

In addition, a heat exchange refrigerant pipe 23 is connected between the suction side of the GHP compressor 13 and the refrigerant pipe 20 , and the heat exchange refrigerant pipe 23 connects the suction side of the GHP compressor 13 and the refrigerant pipe 20 . The heat exchange refrigerant piping 23 is provided with an electric valve 26 . A plate heat exchanger 27 is provided between the electric valve 26 of the heat exchange refrigerant piping 23 and the suction side of the GHP compressor 13 .

The GHP outdoor unit 2 includes a bypass pipe 28 connecting the discharge side and the suction side of the GHP compressor 13 . One end of the bypass pipe 28 is connected between the oil separator 15 and the four-way valve 16 , and the other end of the bypass pipe 28 is connected between the accumulator 19 and the four-way valve 16 . A part of the refrigerant on the discharge side of the GHP compressor 13 flows to the suction side of the GHP compressor 13 through the bypass pipe 28 due to the pressure difference.

A bypass valve 29 for adjusting the flow rate of the bypass pipe 28 is provided in the bypass pipe 28 . The bypass valve 29 is an electric valve that can be opened and closed in stages.

The GHP outdoor unit 2 includes an oil return pipe 30 connecting the oil separator 15 and the suction side of the GHP compressor 13 . Due to the pressure difference between the discharge side and the suction side of the GHP compressor 13 , the lubricating oil stored in the oil separator 15 flows to the suction side through the oil return pipe 30 .

The oil return pipe 30 includes a first return pipe 31 connecting the oil outlet of the oil separator 15 and the suction side of the GHP compressor 13 , and a second return pipe 36 provided in parallel with the first return pipe 31 .

The first return tube 31 includes a capillary tube 32 .

The second return pipe 36 is connected to the first return pipe 31 so as to bypass the capillary 32 , one end of the second return pipe 36 is connected to the upstream side of the capillary 32 in the first return pipe 31 , and the other end of the second return pipe 36 is connected It is connected to the downstream side of the capillary 32 in the first return pipe 31 .

The second return pipe 36 includes a capillary 33 and an oil return valve 34 provided downstream of the capillary 33 .

The oil connection valve 11 is connected to the oil pipe 35 . The oil pipe 35 is branched in the middle, one of which is connected to a position closer to the downstream side than the oil separator 15 of the refrigerant piping 20 , and the other is connected between the capillary 33 of the second return pipe 36 and the oil return valve 34 . .

The external connection valve 10 a connected to the refrigerant piping 20 is connected to one end of the indoor heat exchanger 40 of each indoor unit 4 via the inter-unit piping 5 . An expansion valve 41 is provided in the middle of the inter-unit piping 5 .

Inside each indoor unit 4, an indoor fan 42 for performing heat exchange between the indoor heat exchanger 40 and indoor air is provided.

Moreover, the other end of each indoor heat exchanger 40 is connected to the external connection valve 10b via the inter-unit piping 5, and the refrigerant piping 20 is connected to the external connection valve 10b.

Furthermore, the GHP outdoor unit 2 includes the cooling water circuit 50 of the gas engine 12 .

The cooling water circuit 50 includes a cooling water three-way valve 52 connected in this order from the gas engine 12 via a cooling water pipe 51, a plate heat exchanger 27, a radiator 53 arranged close to one outdoor heat exchanger 17, a cooling water pump 54, The cooling water is circulated in the circuit by driving the cooling water pump 54 with the exhaust gas heat exchanger 55 of the gas engine 12 .

The cooling water piping 51 of the cooling water circuit 50 is indicated by a double-dashed line in FIG. 1 , and the flow of the cooling water is indicated by a solid arrow.

Heat exchange between the outside air and the cooling water is performed at the radiator 53 .

Further, in the plate heat exchanger 27 , by the operation of the electric valve 26 , the refrigerant returned to the GHP compressor 13 is heated by the cooling water flowing through the cooling water pipe 51 . Thereby, the low-pressure pressure of the refrigerant increases, and the heating efficiency improves.

The cooling water circuit 50 can form a first path through which the cooling water flows sequentially through the gas engine 12 , the cooling water three-way valve 52 , the radiator 53 , the cooling water pump 54 , the exhaust gas heat exchanger 55 and the gas engine 12 .

In addition, the cooling water circuit 50 can form a second path through which cooling water flows sequentially through the gas engine 12 , the cooling water three-way valve 52 , the plate heat exchanger 27 , the cooling water pump 54 , the exhaust gas heat exchanger 55 and the gas engine 12 .

A warm water three-way valve 56 is provided in the middle of the first path connecting the radiator 53 and the cooling water three-way valve 52 . The warm water three-way valve 56 is connected to a warm water heat exchanger 57 for exchanging heat between cooling water and warm water, and the cooling water passing through the warm water heat exchanger 57 is returned to the upstream side of the cooling water pump 54 .

Next, the EHP outdoor unit 3 will be described.

The EHP outdoor unit 3 includes two external connection valves 60 for connection to the external inter-unit piping 5 , and an oil connection valve 61 for connection to the oil balance piping 6 .

The EHP outdoor unit 3 includes an EHP compressor 62 driven by a commercial power source. The EHP compressor 62 is, for example, an inverter compressor whose output can be varied.

An oil separator 63 , a four-way valve 64 , and two outdoor heat exchangers 65 and 65 are sequentially connected to the discharge side of the EHP compressor 62 . An outdoor fan 105 (see FIG. 2 ) for exchanging heat between the outdoor heat exchanger 65 and the outside air is provided near the outdoor heat exchanger 65 .

A subcooling heat exchanger 90 is provided between the outdoor heat exchanger 65 and the external connection valve 60a.

The outdoor heat exchanger 65 is formed with two-system piping, and the refrigerant piping 66 on the four-way valve 64 side and the refrigerant piping 66 on the subcooling heat exchanger 90 side are branched and connected to the outdoor heat exchanger 65 . In addition, the outdoor electronic control valves 68 and 68 are respectively provided in the refrigerant piping 66 on the subcooling heat exchanger 90 side of the outdoor heat exchanger 65 .

The subcooling heat exchanger 90 includes two heat exchange units 91 and 91, and the refrigerant piping 66 on the side of the outdoor heat exchanger 65 and the refrigerant piping 67 on the side of the external connection valve 60a are each branched and connected to the subcooling heat exchanger 90. Each heat exchange unit 91 is connected.

In the present embodiment, each heat exchange unit 91 is configured as a double-pipe heat exchanger, and the piping outside the heat exchange unit 91 is configured to be connected to the refrigerant piping 66 on the outdoor heat exchanger 65 side and the external connection valve 60a side, respectively. The refrigerant piping 67 is connected.

The intermediate portion of the refrigerant piping 67 connecting the subcooling heat exchanger 90 and the external connection valve 60a is connected to a subcooling branch pipe 92 that exchanges heat with each heat via the subcooling electronic control valve 93 on the way. The inner piping 94 of the unit 91 is connected. The refrigerant that has passed through the inner piping 94 of the heat exchange unit 91 is configured to return to the refrigerant piping 66 between the four-way valve 64 and the accumulator 69 via the subcooled refrigerant piping 95 .

The other external connection valve 60b is connected to the suction side of the EHP compressor 62 via a refrigerant pipe 66, and a four-way valve 64 and an accumulator 69 are provided in the middle of the refrigerant pipe 66. As shown in FIG.

Further, a refrigerant return pipe that is branched and connected to the refrigerant pipe 66 between the EHP compressor 62 and the accumulator 69 is provided in the middle of the refrigerant pipe 66 between the EHP compressor 62 and the oil separator 63 . 70. In the middle part of the refrigerant return piping 70, a refrigerant return solenoid valve 71 is provided. Furthermore, when the solenoid valve 71 for refrigerant return is opened, a part of the refrigerant is introduced to the suction side of the EHP compressor 62 without circulating in the refrigeration cycle.

In addition, the lower part of the oil separator 63 is connected to an oil pipe 72 , and an intermediate portion of the oil pipe 72 is connected to an oil return pipe 73 connected to the suction side of the EHP compressor 62 . The oil return piping 73 includes two branch pipes 74 and 75 branched from the oil pipe 72 , the oil return valve 76 is provided in one branch pipe 74 , and the capillary 78 is provided in the other branch pipe 75 . In addition, a capillary 79 is provided between the connecting portions of the respective branch pipes 74 and 75 of the oil pipe 72 .

A midway portion of the refrigerant piping 66 between the oil separator 63 and the four-way valve 64 is connected to a high-pressure refrigerant piping 80 , which branches midway and is connected to an midway portion of the oil pipe 72 . A high-pressure refrigerant solenoid valve 81 is provided in the middle of the high-pressure refrigerant piping 80 .

Furthermore, the accumulator 69 includes an inflow pipe 82 into which the refrigerant of the refrigerant piping 66 flows, and an outflow pipe 83 that sends the gas refrigerant inside the accumulator 69 to the EHP compressor 62 . The outflow pipe 83 is configured to open above the inside of the accumulator 69 , and is configured to send the gas refrigerant accumulated above the inside of the accumulator 69 to the EHP compressor 62 .

In addition, the EHP compressor 62 is connected to an overflow pipe 84 which is connected to the suction side of the EHP compressor 62 . The overflow pipe 84 is assembled with a filter 85 and a throttle 86 for depressurizing the oil.

The external connection valve 60a of the EHP outdoor unit 3 is connected to one end of the inter-unit piping 5, and the other end of the inter-unit piping 5 is connected to the midway portion of the inter-unit piping 5 that connects the external connection valve 10a of the GHP outdoor unit 2 and the indoor unit 4 . The external connection valve 60b connected to the refrigerant piping of the EHP outdoor unit 3 is connected to one end of the inter-unit piping 5, and the other end of the inter-unit piping 5 is connected to the external connection valve 10b of the GHP outdoor unit 2 and the inter-unit of the indoor unit 4. The middle part of the piping 5 is connected.

In addition, the oil connection valve 61 of the EHP outdoor unit 3 and the oil connection valve 11 of the GHP outdoor unit 2 are connected via the oil balance pipe 6 . Thereby, oil can be mutually supplied between the GHP compressor 13 of the GHP outdoor unit 2 and the EHP compressor 62 of the EHP outdoor unit 3 via the oil balance pipe 6, and the EHP compressor 62 of the GHP outdoor unit 2 and the EHP outdoor unit can be held. 3. Balance of oil volume of EHP compressor 62.

When the cooling operation is performed, the refrigerant flows as indicated by the solid arrows in FIG. 1 , and when the heating operation is performed, the refrigerant flows as indicated by the broken lines in FIG. 1 .

In the present embodiment, the GHP oil level sensor 106 is provided in the first return pipe 31 of the GHP outdoor unit 2 . In addition, an EHP oil level sensor 107 is provided in the overflow pipe 84 of the EHP outdoor unit 3 .

Next, the control structure of the air-conditioning apparatus of this embodiment is demonstrated. FIG. 2 is a block diagram showing a control structure of the present embodiment.

As shown in FIG. 2 , in the present embodiment, the GHP outdoor unit 2 includes a GHP control unit 100 as a control unit, and the EHP outdoor unit 3 includes an EHP control unit 101 as a control unit. Further, the indoor units 4 each include indoor control units 102 .

In addition, in the present embodiment, the air-conditioning apparatus includes the controller 110 that transmits a control instruction signal to the GHP outdoor unit 2 , the EHP outdoor unit 3 , and the indoor unit 4 .

The controller 110 includes a controller control unit 111 for collectively controlling the GHP control unit 100 , the EHP control unit 101 , and the indoor control unit 102 .

These GHP control unit 100 , EHP control unit 101 , indoor control unit 102 , and controller control unit 111 include, for example, an arithmetic processing circuit such as a CPU, ROM, RAM, etc. as storage means, and are control units that perform predetermined control by executing predetermined programs. .

The GHP control unit 100 is configured to perform drive control of the gas engine 12 , the outdoor fan 18 , and the cooling water pump 54 of the GHP outdoor unit 2 , and to perform the external connection valves 10 a and 10 b , the oil connection valve 11 , the electric valve 24 , the external connection valves 10 a and 10 b of the GHP outdoor unit 2 , and the Open/close control or opening degree control of the electric valve 26 , the bypass valve 29 , the oil return valve 34 , and the cooling water three-way valve 52 .

The EHP control unit 101 is configured to perform drive control of the EHP compressor 62 and the outdoor fan 105 of the EHP outdoor unit 3 , and to perform the external connection valves 60 a and 60 b , the oil connection valve 61 , the outdoor electronic control valve 68 , and the external connection valves 60 a and 60 b of the EHP outdoor unit 3 . The solenoid valve 71 for refrigerant return, the oil return valve 76 , the solenoid valve 81 for high pressure refrigerant, and the electronic control valve 93 for supercooling are open-close control or opening degree control.

The indoor control unit 102 is configured to control the drive of the indoor fan 42 of the indoor unit 4 and to control the opening degree of the expansion valve 41 of the indoor unit 4 .

The control by the GHP control unit 100 , the EHP control unit 101 , and the indoor control unit 102 is performed based on a control instruction signal transmitted from the controller control unit 111 .

At this time, in the present embodiment, the GHP control unit 100 is set as the master control unit, and the EHP control unit 101 and the indoor control unit 102 are set as the slave control units, and the control instruction signal from the controller control unit 111 is firstly processed. The control instruction signal is transmitted to the GHP control unit 100, and the control instruction signal is configured to be sequentially transmitted from the GHP control unit 100 to the EHP control unit 101 and the indoor control unit 102.

In this embodiment, the GHP outdoor unit 2 and the EHP outdoor unit 3 adjust the output according to the cooling load. For example, when the cooling load is low, the EHP outdoor unit 3 is driven, the EHP outdoor unit 3 is stopped as the cooling load increases, and the GHP outdoor unit 2 is started. When the cooling load becomes a high load, in addition to the driving of the GHP outdoor unit 2, the EHP outdoor unit 3 is also driven.

The system control unit 103 controls the GHP outdoor unit 2, the EHP outdoor unit 3, and the indoor unit 4 based on the number of indoor units 4 in operation, the set temperature, the outside air temperature, etc. The operation of the outdoor unit 3 is the most energy-saving mode, and a control signal is output to the GHP control unit 100 , the EHP control unit 101 , and the indoor control unit 102 . As a result, the operation control of the GHP outdoor unit 2 by the GHP control unit 100 , the operation control of the EHP outdoor unit 3 by the EHP control unit 101 , and the operation control of the indoor unit 4 by the indoor control unit 102 can be efficiently configured. .

In this case, in the present embodiment, when the cooling operation is performed by only one of the GHP outdoor unit 2 and the EHP outdoor unit 3 and the other outdoor unit is stopped, the GHP control unit 100 or the EHP control unit 101 Based on the detection value from the oil level sensor of the outdoor unit in operation, it is determined whether the oil level is lower than a certain level, and when it is determined that the oil level is lower than the certain level, the oil return valve 34 of the outdoor unit in operation is opened. Or 76 way to control.

Specifically, for example, when only the GHP outdoor unit 2 performs the cooling operation and the EHP outdoor unit 3 is stopped, the GHP control unit 100 determines whether or not the oil level in the GHP outdoor unit 2 is low based on the detection value from the GHP oil level sensor 106 . At a certain level, when it is determined that the oil level is lower than a certain level, control is performed so as to open the oil return valve 34 of the GHP outdoor unit 2 .

In addition, for example, when only the EHP outdoor unit 3 performs the cooling operation and the GHP outdoor unit 2 is stopped, the EHP control unit 101 determines whether or not the oil level in the EHP outdoor unit 3 is lower than a certain value based on the detection value from the EHP oil level sensor 107 . When it is determined that the oil level is lower than a certain level, the control is performed so as to open the oil return valve 76 of the EHP outdoor unit 3 .

In addition, the GHP control unit 100 or the EHP control unit 101 starts the cooling operation of both the GHP outdoor unit 2 and the EHP outdoor unit 3 when the cooling operation is performed from one of the GHP outdoor unit 2 and the EHP outdoor unit 3. In this case, or the oil level based on the detection value from the oil level sensor of the operating outdoor unit becomes higher than a certain level from the state in which one of the GHP outdoor unit 2 and the EHP outdoor unit 3 is in cooling operation Next, the GHP control unit 100 or the EHP control unit 101 ends the control to open the oil return valves 34 and 76 .

In addition, in the present embodiment, when the protection control operation is performed, the GHP control unit 100 or the EHP control unit 101 also ends the control to open the oil return valves 34 and 76 .

Here, there are other priority control operations and the like among the protection control operations.

Next, the operation of this embodiment will be described with reference to the flowchart shown in FIG. 3 .

FIG. 3 is a flowchart showing the operation of the present embodiment.

As shown in FIG. 3 , in the present embodiment, first, the GHP control unit 100 or the EHP control unit 101 drives the GHP outdoor unit 2 or the EHP outdoor unit 3 in accordance with an instruction signal from the controller control unit 111 to perform cooling operation. (ST1).

Then, in this state, for example, when only the GHP outdoor unit 2 is operated and the EHP outdoor unit 3 is stopped ( ST2 : YES), the GHP control unit 100 determines whether or not the oil level is lower than the oil level based on the detection value from the GHP oil level sensor 106 . certain level (ST3).

When it is determined that the oil level is lower than a certain level ( ST4 : YES), the GHP control unit 100 performs control to open the oil return valve 34 ( ST5 ).

By controlling in this way, the oil connection valves 11 and 61 are communicated via the oil balance pipe 6 , so that high pressure is not applied to the discharge side of the oil return valve 76 of the EHP outdoor unit 3 , and the refrigerant and oil can be prevented from accumulating in the EHP outdoor unit 3 . In addition, the refrigerant and oil accumulated in the oil pipe 72 and the high-pressure refrigerant pipe 80 of the EHP outdoor unit 3 can be sent to the suction side of the GHP compressor 13 via the oil pipe 35 and the oil return valve 34 .

Then, the GHP control unit 100 of the GHP outdoor unit 2 ends the control to open the oil return valve 34 when the EHP outdoor unit 3 is activated and the cooling operation is performed using the GHP outdoor unit 2 and the EHP outdoor unit 3 (ST6: YES). (ST9).

Further, the oil level is monitored based on the detection value from the GHP oil level sensor 106, and when it is determined that the oil level is higher than a certain level (ST7: YES), the control to open the oil return valve 34 is ended (ST9).

Then, when the protection control operation is performed (ST8: YES), the control to open the oil return valve 34 is ended (ST9).

This control is performed because, when both the GHP outdoor unit 2 and the EHP outdoor unit 3 are operating, the pressure balance of the GHP outdoor unit 2 and the EHP outdoor unit 3 can be maintained, so there is no pressure in the GHP outdoor unit 2 or the EHP outdoor unit 3. The problem of oil accumulation in one of the units 3.

Also because, if the oil level is above a certain level, there is no problem of hot sticking. Furthermore, when the protection control operation is performed, it is necessary to give priority to the control that is more important than the accumulation of oil.

In addition, in the description of the operation of the above-described embodiment, an example in which only the GHP outdoor unit 2 is operated has been described, but when only the EHP outdoor unit 3 is operated, the EHP control unit 101 detects based on the detection value of the EHP oil level sensor 107 The oil level is controlled so that the oil return valve 76 is opened, and the same control can be performed.

As described above, in the present embodiment, the oil return pipes 30 and 73 provided on the discharge side of the compressors of the GHP outdoor unit 2 and the EHP outdoor unit 3 are provided to return the oil to the suction side, and the oil return pipes 30 and 73 are provided. Oil return valves 34 and 76 in the middle of 30 and 73; oil level sensors for detecting oil levels of GHP outdoor unit 2 and EHP outdoor unit 3; and GHP control section 100 and EHP for controlling GHP outdoor unit 2 and EHP outdoor unit 3 control unit 101 . The GHP control unit 100 or the EHP control unit 101 performs cooling operation in the GHP outdoor unit 2 (EHP outdoor unit 3) using only one of the GHP outdoor unit 2 and the EHP outdoor unit 3, and the other EHP outdoor unit 3 (GHP outdoor unit 3) When unit 2) is stopped, it is judged whether the oil level is lower than When it is determined that the oil level is lower than a certain level, control is performed so as to open the oil return valve 34 (76) of the GHP outdoor unit 2 (EHP outdoor unit 3) in operation.

As a result, by opening the oil return valve 34 (76), the GHP outdoor unit 2 (EHP outdoor unit 3) in cooling operation and the EHP outdoor unit 3 (GHP outdoor unit 2) in stop are communicated via the oil balance pipe 6 and stopped. High pressure is not applied to the discharge side of the oil return valve 76 (34) of the EHP outdoor unit 3 (GHP outdoor unit 2) in the middle, and it is possible to prevent refrigerant and oil from accumulating in the EHP outdoor unit 3 (GHP outdoor unit 2). In addition, the refrigerant and oil stored in the EHP outdoor unit 3 (GHP outdoor unit 2 ) that is being stopped can be sent to the GHP compressor 13 (EHP compressor 13 (EHP compressor) of the GHP outdoor unit 2 (EHP outdoor unit 3 ) that is in cooling operation 62) on the suction side. As a result, the oil of the GHP compressor 13 (EHP compressor 62 ) in the cooling operation can be sufficiently secured, and hot sticking can be prevented.

In addition, in the present embodiment, the GHP control unit 100 or the EHP control unit 101, when two or more GHP outdoor units 2 and EHP outdoor units 3 are operating When the oil level of the detection value of the sensor 107 is higher than a certain level, or when the protection control operation is performed, the control to open the oil return valve 34 ( 76 ) ends.

Thereby, when the oil of the GHP compressor 13 (EHP compressor 62) can be secured, the opening control of the oil return valve 34 (76) is terminated, and the supply of unnecessary oil can be stopped.

In addition, the above-mentioned embodiment is an example which shows one form to which this invention is applied, and this invention is not limited to the said embodiment.

In the above-mentioned embodiment, the case where a plurality of outdoor units are constituted by the GHP outdoor unit 2 and the EHP outdoor unit 3 has been described, but the present invention is not limited to this. For example, only a plurality of GHP outdoor units 2 may constitute the outdoor unit, and only a plurality of EHP outdoor units 3 may constitute an outdoor unit.

In addition, in the said embodiment, the case where the GHP control part 100 is set as a master control part and the EHP control part 101 is set as a slave control part was demonstrated as an example, but this invention is not limited to this. For example, the EHP control unit 101 may be set as the master control unit, the GHP control unit 100 may be set as the slave control unit, and the control instruction signal from the controller control unit 111 may be sent to the EHP control unit 101 first.

In addition, without setting the master control unit and the slave control unit, the GHP control unit 100, the EHP control unit 101, and the indoor control unit 102 may be connected in parallel with the controller control unit 111, and the slave control unit 111 may be connected to the GHP control unit, respectively. 100. The EHP control unit 101 and the indoor control unit 102 send a control instruction signal.

industrial availability

As described above, the air-conditioning apparatus of the present invention is suitable for use as an air-conditioning apparatus in which the discharge side of the oil return valve of the outdoor unit being stopped does not work when the cooling operation is performed by only one outdoor unit. High pressure is applied to prevent refrigerant and oil from accumulating in the stopped outdoor unit. In addition, the oil accumulated in the stopped outdoor unit can be supplied to the outdoor unit in the cooling operation, the oil of the compressor in the cooling operation can be sufficiently secured, and thermal sticking can be prevented.

Claims (3)

1. An air conditioning device characterized in that:

a plurality of outdoor units connected to the indoor units via inter-unit pipes, respectively, each of the outdoor units being operated to perform indoor air conditioning by the indoor unit,

the air conditioning device includes:

an oil return pipe provided on a discharge side of a compressor of the outdoor unit and returning oil to a suction side;

an oil return valve provided in a middle portion of the oil return pipe;

an oil level sensor that detects an oil level of the outdoor unit; and

a control part for controlling the outdoor unit,

the control unit determines whether or not an oil level is lower than a predetermined level based on a detection value from the oil level sensor of the operating outdoor unit when cooling operation is performed by only 1 of the outdoor units and the other outdoor units are stopped, and controls to open the oil return valve of the operating outdoor unit when the oil level is determined to be lower than the predetermined level.

2. The air conditioning unit according to claim 1, characterized in that:

the control unit terminates the control of opening the oil return valve when the oil level based on the detection value from the oil level sensor is higher than a certain level or when a protection control operation is performed in a case where the outdoor unit 2 is operated at or above a predetermined number.

3. The air conditioning device according to claim 1 or 2, characterized in that:

the plurality of outdoor units are GHP outdoor units including GHP compressors driven by an engine, and EHP outdoor units including EHP compressors driven by a commercial power supply.

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