WO2019087407A1

WO2019087407A1 - Air conditioning device

Info

Publication number: WO2019087407A1
Application number: PCT/JP2017/040000
Authority: WO
Inventors: 松岡　慎也; 鈴木　秀一
Original assignee: ダイキン工業株式会社
Priority date: 2017-11-06
Filing date: 2017-11-06
Publication date: 2019-05-09
Also published as: SG11202003551QA; JP6860082B2; JPWO2019087407A1

Abstract

Provided is an air conditioning device whereby refrigerant suddenly pooling in a condenser can escape from the condenser. The air conditioning device (100) comprises: a plurality of indoor units (20) each having an electrically operated valve (21) and an indoor heat exchanger (22) and each having the operation thereof turned ON and OFF independently; an outdoor unit (10) having a compressor (11) and an outdoor heat exchanger (12) and having the plurality of indoor units (20) connected thereto; and a control device (50) that controls the degree of opening of the expansion valves (21). The control device (50) increases the degree of opening of the expansion valves (21) in the operating indoor units (20) during operation capacity reductions whereby the total operation capacity of the plurality of indoor units (20) has been reduced at a prescribed time at a prescribed rate.

Description

Air conditioner

The present invention relates to an air conditioner.

An air conditioner is conventionally known that includes a refrigerant circuit in which a compressor, a condenser, a motor-operated valve, and an evaporator are connected. Patent Document 1 (Japanese Patent Laid-Open No. 2015-124958) describes an air conditioner that reduces the fan rotational speed of the indoor unit when the low pressure exceeds the upper limit during cooling operation under high outside air. ing.

However, according to Patent Document 1 (Japanese Patent Laid-Open No. 2015-124958), when the high-pressure pressure rises rapidly during the cooling operation under high outside air, the refrigerant liquid which is rapidly accumulated in the condenser is There is no mention of getting it out of the condenser. An object of the present disclosure is to release the refrigerant liquid, which rapidly accumulates in the condenser, from the condenser.

An air conditioner according to a first aspect of the present disclosure includes a plurality of indoor units, a compressor, and a plurality of indoor units each having an expansion valve and an evaporator, and the ON and OFF of the operation are individually operated. And an outdoor unit to which a plurality of indoor units are connected, and a control device for controlling the degree of opening of the expansion valve, the control device having a total operating capacity of the plurality of indoor units for a predetermined time When the operating capacity decreases by a predetermined rate, the opening degree of the expansion valve of the operating indoor unit is increased.

Therefore, according to the present disclosure, the refrigerant liquid that rapidly accumulates in the condenser can be released from the condenser.

An air conditioner according to a second aspect of the present disclosure includes a plurality of indoor units, a compressor, and a plurality of indoor units each having an expansion valve and an evaporator, and are individually operated ON or OFF. And an outdoor unit to which a plurality of indoor units are connected, and a controller for controlling the degree of opening of the expansion valve, the controller having a total operating capacity of the plurality of indoor units within a predetermined time When the operating capacity decreases by a predetermined rate and the high pressure is equal to or higher than the first predetermined value, the opening degree of the expansion valve of the operating indoor unit is increased.

In the air conditioner according to the third aspect of the present disclosure, the control device increases the opening degree of the expansion valve according to the differential pressure between the high pressure and the low pressure when the operating capacity decreases.

In the air conditioner according to the fourth aspect of the present disclosure, the control device increases the opening degree of the expansion valve according to the degree of subcooling of the outlet of the condenser when the operating capacity decreases.

In the air conditioner according to the fifth aspect of the present disclosure, the control device sets the opening degree of the expansion valve such that the degree of superheat at the outlet of the evaporator becomes the target degree of superheat during normal operation different from when increasing or decreasing the operating capacity. Control.

In the air conditioner according to the sixth aspect of the present disclosure, the control device sets the opening degree of the expansion valve to full opening when the operating capacity decreases.

In the air conditioner according to the seventh aspect of the present disclosure, the control device reduces the operating capacity of the compressor if the high pressure of the air conditioner is equal to or higher than the second pressure.

In the air conditioner according to the eighth aspect of the present disclosure, the control device stops the compressor if the high pressure is equal to or higher than the third pressure.

An air conditioner according to a ninth aspect of the present disclosure is a cooling-dedicated device, and does not have a container for adjusting the amount of refrigerant.

It is a refrigerant | coolant system diagram of an air conditioning apparatus. It is a flowchart of motor-operated valve control at the time of normal operation. It is a flowchart of compressor capacity control at the time of normal operation. It is a flowchart of high pressure protection control at the time of normal operation. It is a flowchart of motor-operated valve control at the time of refrigerant retention. It is the same time chart. It is a flowchart of motor-operated valve control at the time of high pressure rise. It is the same time chart. It is a flowchart of motor-operated valve control at the time of operation capacity reduction. It is the same time chart. It is a flowchart of compressor capacity control at the time of operating capacity increase. It is the same time chart.

Hereinafter, an embodiment of an air conditioning apparatus 100 according to the present disclosure will be described based on the drawings. In addition, the specific structure of the air conditioning apparatus 100 which concerns on this indication is not restricted to following embodiment, It can change in the range which does not deviate from the summary of indication.

<Air conditioner>
(1) Overall Configuration The overall configuration of the air conditioning apparatus 100 will be described using FIG. The broken lines in FIG. 1 represent electrical signal lines. In the following, the upstream side or the downstream side is defined according to the flow direction of the refrigerant.

The air conditioning apparatus 100 is an apparatus for cooling a room such as a building using a vapor compression refrigeration cycle. The air conditioner 100 is a cooling dedicated device. The air conditioning apparatus 100 includes an outdoor unit 10, four

indoor units

20a, 20b, 20c, and 20d,

connection pipes

41 and 42, and a controller 50 as a control device.

(1-1) Outdoor Unit The outdoor unit 10 is provided outside the building. The outdoor unit 10 includes a compressor 11, an outdoor heat exchanger 12 as a condenser, and an outdoor fan 13. The compressor 11, the outdoor heat exchanger 12, and the outdoor fan 13 are accommodated in an outdoor casing (not shown).

The compressor 11 feeds refrigerant gas from low pressure to high pressure. A suction pipe 31 is connected to the low pressure side of the compressor 11. A low pressure sensor 61 is provided in the vicinity of the compressor 11 of the suction pipe 31. A discharge pipe 32 is connected to the high pressure side of the compressor 11. A high pressure sensor 62 and a high pressure shutoff pressure switch 82 are provided in the vicinity of the compressor 11 of the discharge pipe 32.

The outdoor heat exchanger 12 exchanges heat between the air and the refrigerant, and condenses the refrigerant gas into the refrigerant liquid. The upstream side of the outdoor heat exchanger 12 is connected to the discharge pipe 32. The downstream side of the outdoor heat exchanger 12 is connected to the liquid pipe 33. An outdoor heat exchanger outlet temperature sensor 71 is provided in the vicinity of the outdoor heat exchanger 12 of the liquid pipe 33. That is, the outdoor heat exchanger outlet temperature sensor 71 is provided at the outlet of the outdoor heat exchanger 12.

The outdoor fan 13 is driven by an electric motor (not shown) and blows air toward the outdoor heat exchanger 12. An outdoor suction air temperature sensor 74 is provided on the suction side of the outdoor fan 13. Specifically, the outdoor suction air temperature sensor 74 is provided at the air suction port of the outdoor casing.

The low pressure sensor 61 detects the refrigerant gas sucked by the compressor 11, that is, the low pressure LP of the air conditioner 100. The high pressure sensor 62 detects the refrigerant gas compressed by the compressor 11, that is, the high pressure HP of the air conditioner 100. The outdoor heat exchanger outlet temperature sensor 71 detects the temperature of the refrigerant liquid at the outlet of the outdoor heat exchanger 12 (outdoor heat exchanger outlet temperature Tco). The outdoor suction air temperature sensor 74 detects the indoor suction air temperature Tb of the outdoor unit 10.

The high pressure shutoff pressure switch 82 stops the air conditioner 100 if the high pressure HP of the air conditioner 100 is equal to or higher than a predetermined value HPm.

(1-2) Indoor Unit The indoor unit 20a is provided in a room of a building. The indoor unit 20a is connected to the outdoor unit 10 by a communication pipe (liquid pipe 33 and suction pipe 31). The indoor unit 20a includes an electric valve 21a as an expansion valve, an indoor heat exchanger 22a as an evaporator, an indoor fan 23a, and a remote controller (not shown). The motor operated valve 21a, the indoor heat exchanger 22a and the indoor fan 23a are accommodated in an indoor casing (not shown).

The motor operated valve 21 a is for expanding the refrigerant liquid into a gas-liquid mixed refrigerant. The motor operated valve 21a is electrically driven to perform an operation of increasing or decreasing the degree of opening. The upstream side of the motor operated valve 21 a is connected to the communication pipe 41.

The indoor heat exchanger 22a exchanges heat between the air and the refrigerant to evaporate the gas-liquid mixed refrigerant into the refrigerant gas. The downstream side of the indoor heat exchanger 22 a is connected to the communication pipe 42. The indoor heat exchanger outlet temperature sensor 72a is provided at the outlet of the indoor heat exchanger 22a.

The indoor fan 23a is driven by an electric motor (not shown) and blows air toward the indoor heat exchanger 22a. An indoor suction air temperature sensor 73a is provided on the suction side of the indoor fan 23a. Specifically, the indoor suction air temperature sensor 73a is provided at the air suction port of the indoor casing.

The remote control is for the user to input ON / OFF of the indoor unit 20a or the set temperature Ts in the room.

The indoor heat exchanger outlet temperature sensor 72a detects the temperature of the refrigerant gas at the outlet of the indoor heat exchanger 22a (the indoor heat exchanger outlet temperature Teo). The indoor suction air temperature sensor 73a detects the indoor suction air temperature Ta of the indoor unit 20a.

The

indoor units

20b, 20c, and 20d are the same as the configuration of the indoor unit 20a, and thus the description thereof is omitted. In addition, below, when showing any of

indoor unit

20a, 20b, 20c, 20d, it is only set as the indoor unit 20. FIG. The same applies to the motor operated valve 21, the indoor heat exchanger 22, the indoor heat exchanger outlet temperature sensor 72 or the indoor suction air temperature sensor 73.

The controller 50 includes a control board (not shown) provided on the outdoor unit 10 communicably connected to each other by wire or wirelessly and a control board (not shown) provided on the

indoor units

20a, 20b, 20c, 20d. Is configured. Further, the controller 50 includes one or more CPUs, a ROM, a RAM, and the like.

The controller 50 includes a low pressure sensor 61, a high pressure sensor 62, a high pressure cutoff pressure switch 82, an outdoor heat exchanger outlet temperature sensor 71, a motor operated valve 21, an indoor heat exchanger outlet temperature sensor 72, and indoor suction. The air temperature sensor 73 and the remote controller of the indoor unit 20 are connected.

The controller 50 has a function of changing the rotational frequency of the compressor 11 to control the operating capacity Cap of the compressor 11. The controller 50 has a function of controlling the opening degree of the motor-operated valve 21.

The controller 50 has a function of detecting the operating capacity TON of the indoor unit 20. Here, the indoor unit 20 has a capacity. The operating capacity TON represents the capacity of the indoor unit 20 being operated (thermo-ON). Note that, with the operating capacity TON, the capacity of the indoor unit 20 that is thermo-OFF is excluded.

Here, it should be noted that the air conditioner 100 is not provided with a container for adjusting the amount of refrigerant, such as a receiver and an accumulator.

(1-3) Communication Piping The

communication pipes

41, 42 are for connecting the outdoor unit 10 and the plurality of

indoor units

20a, 20b, 20c, 20d.

(2) Cooling Operation The cooling operation of the air conditioner 100 will be described with reference to FIG. In order to make the explanation easy to understand, it is assumed that the

indoor units

20b, 20c and 20d are turned off, and only the cooling operation of the indoor unit 20a will be described.

The high temperature and high pressure refrigerant gas compressed by the compressor 11 flows toward the outdoor heat exchanger 12. In the outdoor heat exchanger 12, the high-temperature and high-pressure refrigerant gas is deprived of heat by the air and condensed into the refrigerant liquid. The condensed refrigerant liquid flows toward the motor-operated valve 21a.

The refrigerant liquid is expanded into a gas-liquid mixed refrigerant by the motor-operated valve 21a. The gas-liquid mixed refrigerant flows toward the indoor heat exchanger 22a. In the indoor heat exchanger 22a, the gas-liquid mixed refrigerant is given heat by the air and evaporated to a refrigerant gas. The evaporated refrigerant gas is drawn into the compressor 11.

(3-1) Motorized Valve Control in Normal Operation The motored valve control S100 in normal operation will be described with reference to FIG. The normal operation is a cooling operation, and is different from the control at the time of refrigerant retention, the time of high pressure rise, and the time of reduction of the operating capacity, which will be described later. In order to make the explanation easy to understand, it is assumed that the

indoor units

20b, 20c and 20d are turned off, and only the normal operation of the indoor unit 20a will be described.

In step S101, the controller 50 detects the indoor heat exchanger outlet temperature Teo by the indoor heat exchanger outlet temperature sensor 72a. In step S102, the controller 50 detects the low pressure LP by the low pressure sensor 61. In step S103, the controller 50 calculates the evaporation temperature Te from the low pressure LP.

In step S104, the controller 50 calculates the degree of superheat SH at the outlet of the indoor heat exchanger 22a from the indoor heat exchanger outlet temperature Teo and the evaporation temperature Te. In step S105, the controller 50 decreases the degree of opening of the motor operated valve 21a when the degree of superheat SH is smaller than the target degree of superheat SHm set in advance. On the other hand, when the degree of superheat SH is larger than the target degree of superheat SHm, the controller 50 increases the opening degree of the motor-operated valve 21a.

With such a configuration, the air conditioning apparatus 100 is operated such that the degree of superheat SH of the indoor heat exchanger 22a becomes equal to the target degree of superheat SHm during normal operation. Thus, in the air conditioning apparatus 100, the wet operation or the overheat operation of the compressor 11 can be avoided.

(3-2) Compressor Operating Capacity Control During Normal Operation The compressor operating capacity control S200 during normal operation will be described with reference to FIG. In order to make the explanation easy to understand, it is assumed that the

indoor units

In step S201, the controller 50 detects the indoor suction air temperature Ta by the indoor suction air temperature sensor 73a. In step S202, the controller 50 detects the set temperature Ts set by the remote control.

In step S203, the controller 50 controls the operating capacity Cap of the compressor 11 based on the difference (heat load) between the indoor suction air temperature Ta and the set temperature Ts. Specifically, the controller 50 increases the operating capacity Cap when the difference between the indoor suction air temperature Ta and the set temperature Ts is large, and the difference between the indoor suction air temperature Ta and the set temperature Ts is small. Reduces the operating capacity Cap.

With such a configuration, in the air conditioning apparatus 100, at the time of normal operation, the operating capacity Cap of the compressor 11 is controlled such that the indoor suction air temperature Ta approaches the set temperature Ts. Thus, in the air conditioning apparatus 100, capacity control of the compressor 11 suitable for the heat load is executed, and the indoor suction air temperature Ta can be promptly set to the set temperature Ts.

As a modified example of the compressor operating capacity control S200 during normal operation, the operating capacity Cap of the compressor 11 may be controlled such that the evaporation temperature Te becomes constant at the target evaporation temperature Tem. Specifically, when the evaporation temperature Te is higher than the target evaporation temperature Tem, the operating capacity Cap of the compressor 11 is controlled to be large. On the other hand, when the evaporation temperature Te is lower than the target evaporation temperature Tem, the operating capacity Cap of the compressor 11 is controlled to be small. Here, the target evaporation temperature Tem is set to decrease as the operating capacity TON of the indoor unit 20 increases, and to increase as the operating capacity TON of the indoor unit 20 decreases.

(3-3) High Pressure Protection Control The high pressure protection control S300 will be described with reference to FIG.

In step S301, the controller 50 detects the high pressure HP by the high pressure sensor 62. In step S302, the controller 50 determines whether the high pressure HP is larger than a predetermined value HPn. The predetermined value HPn is smaller than the predetermined value HPm set by the high-pressure shutoff pressure switch 82.

In step S302, when the high pressure HP is larger than the predetermined value HPn, the process proceeds to step S303. If the high pressure HP is less than or equal to the predetermined value HPn, the process returns to S301. In step S303, the controller 50 reduces the operating capacity Cap of the compressor 11.

With such a configuration, in the air conditioning apparatus 100, even when the high pressure HP is increased, the high pressure HP is reduced before the high pressure shutoff pressure switch 82 is operated. Thus, in the air conditioning apparatus 100, it is possible to prevent the high pressure shutoff pressure switch 82 from being operated and stopped.

(3-4) Motorized Valve Control at the Time of Remaining Refrigerant The motored valve control S110 at the time of refrigerant retention will be described with reference to FIG. 5 and FIG. The motor-operated valve control S110 is control for securing the cooling capacity during the cooling operation under high outside air.

(3-4-1) Flow The flow of the motor-operated valve control S110 will be described with reference to FIG. In order to make the explanation easy to understand, the

indoor units

20b, 20c and 20d are described as being turned off.

In step S111, the controller 50 detects the outdoor heat exchanger outlet temperature Tco with the outdoor heat exchanger outlet temperature sensor 71. In step S112, the controller 50 detects the high pressure HP by the high pressure sensor 62. In step S113, the controller 50 calculates the condensation temperature Tc from the high pressure HP.

In step S114, the controller 50 calculates the degree of subcooling SC at the outlet of the outdoor heat exchanger 12 from the outdoor heat exchanger outlet temperature Tco and the condensation temperature Tc. In step S115, the controller 50 proceeds to step S116 when the condensation temperature Tc is equal to or higher than the predetermined temperature Tc1 set in advance. If the condensation temperature Tc is less than the predetermined temperature Tc1, the process returns to S111.

In step S116, the controller 50 proceeds to step S117 when the degree of subcooling SC is greater than or equal to a predetermined value SC1 set in advance. If the degree of subcooling SC is less than the predetermined value SC1, the process returns to S111. In step S117 (during refrigerant retention), the controller 50 determines that the refrigerant liquid is staying in the outdoor heat exchanger 12, and sets the target degree of superheat SHm in the motor-operated valve control S100 low.

(3-4-2) Operation The operation of the motor-operated valve control S110 will be described with reference to FIG. In FIG. 6, with regard to the operation of the motor-operated valve control S110, the condensation temperature Tc, the degree SC of subcooling of the outlet of the outdoor heat exchanger 12, the target degree of superheat SHm of the indoor heat exchanger 22a, the opening degree of the motored valve 21a It represents using the time-sequential change of the working capacity Cap of the machine 11. FIG.

Here, in the air conditioner 100, the refrigerant liquid stagnates in the outdoor heat exchanger 12, the high pressure HP (condensing temperature Tc) rises, the high pressure protection control S300 operates, and the operating capacity Cap of the compressor 11 decreases. Suppose that you

In step S115, the condensation temperature Tc is detected to be equal to or higher than a predetermined temperature Tc1. In step S116, the degree of subcooling SC is detected to be equal to or greater than a predetermined value SC1. Then, in step S116, it is determined that the refrigerant liquid is staying in the outdoor heat exchanger 12, and the target degree of superheat SHm is set to be lower than the current degree.

At this time, in the air conditioning apparatus 100, since the target degree of superheat SHm is set lower than the present time, the opening degree of the motor operated valve 21a increases (6a in FIG. 6). Since the opening degree of the motor operated valve 21 a is increased, the refrigerant liquid accumulated in the outdoor heat exchanger 12 escapes from the outdoor heat exchanger 12.

When the refrigerant liquid staying in the outdoor heat exchanger 12 escapes from the outdoor heat exchanger 12, the condensation temperature Tc decreases (6b in FIG. 6). As the condensation temperature Tc decreases, the high pressure protection control S300 is released. By releasing the high pressure protection control S300, the operating capacity Cap of the compressor 11 is increased (6c in FIG. 6).

(3-4-3) Effects In this manner, in the air conditioning apparatus 100, the refrigerant liquid accumulated in the outdoor heat exchanger 12 can be released from the outdoor heat exchanger 12. At the same time, in the air conditioning apparatus 100, the high pressure protection control S300 is avoided, and a decrease in cooling capacity can be avoided.

(3-5) Motorized Valve Control at the Time of High Pressure Rising The motored valve control S120 at the time of high pressure rising will be described with reference to FIG. 7 and FIG. The motor-operated valve control S120 is control for preventing the high-pressure shutoff pressure switch 82 from stopping the air conditioning apparatus 100 when the high-pressure pressure HP sharply rises in the cooling operation under high outside air.

(3-5-1) Flow The flow of the motor-operated valve control S120 will be described with reference to FIG. In order to make the explanation easy to understand, the

indoor units

20b, 20c and 20d are described as being turned off.

In step S121, the controller 50 detects the high pressure HP from the high pressure sensor 62. In step S122, the controller 50 proceeds to step S123 when the high pressure HP is equal to or greater than a predetermined value HP2 set in advance. If the high pressure HP is less than the predetermined value HP2, the process returns to S121.

In step S123, when the operating capacity Cap of the compressor 11 is equal to or less than a predetermined value Cap2 set in advance, the controller 50 proceeds to step S124. If the operating capacity Cap is larger than the predetermined value Cap2, the process proceeds to step S125.

In step S124 (at the time of high pressure rise), the controller 50 determines that the refrigerant is rapidly staying in the outdoor heat exchanger 12, and increases the opening degree of the motor operated valve 21a by a predetermined amount. In step S125, the controller 50 decreases the operating capacity Cap of the compressor 11 by a predetermined amount.

(3-5-2) Operation The operation of the motor-operated valve control S120 will be described with reference to FIG. In FIG. 8, the function of the motor-operated valve control S120 is expressed using time series changes of the high pressure HP, the operating capacity Cap of the compressor 11, and the opening degree of the motor-operated valve 21a. Here, in the air conditioning apparatus 100, it is assumed that the refrigerant liquid is rapidly staying in the outdoor heat exchanger 12 immediately after startup under high outside air.

In step S122, it is detected that the high pressure HP is equal to or greater than a predetermined value HP2. In step S123, it is detected that the operating capacity Cap of the compressor 11 is equal to or less than a predetermined value Cap2. In step S124, it is determined that the refrigerant is rapidly staying in the outdoor heat exchanger 12, and the opening degree of the motor-operated valve 21a is increased by a predetermined amount.

At this time, in the air conditioning apparatus 100, since the opening degree of the motor-operated valve 21a is increased by a predetermined amount, the refrigerant liquid which rapidly stays in the outdoor heat exchanger 12 escapes from the outdoor heat exchanger 12. The refrigerant liquid staying in the outdoor heat exchanger 12 escapes from the outdoor heat exchanger 12, whereby the high pressure HP decreases (8a in FIG. 8).

(3-5-3) Effects In this manner, in the air conditioning apparatus 100, the refrigerant liquid rapidly staying in the outdoor heat exchanger 12 can be released from the outdoor heat exchanger 12. At the same time, in the air conditioning apparatus 100, the operation of the high pressure shutoff pressure switch 82 can be avoided to prevent the air conditioning apparatus 100 from stopping.

(3-6) Motorized valve control when operating capacity decreases>
Motor-operated valve control S130 at the time of operation capacity reduction is demonstrated using FIG.9 and FIG.10. The motor-operated valve control S130 is control for avoiding the stop of the air conditioner 100 when the operating capacity TON of the indoor unit 20 sharply decreases and the high pressure HP increases rapidly.

(3-6-1) Flow The flow of the motor-operated valve control S130 will be described with reference to FIG. In order to make the description easy to understand, it is assumed that the

indoor units

20b, 20c, 20d are turned off from the state in which the

indoor units

20a, 20b, 20c, 20d are turned on.

In step S131, the controller 50 detects the operating capacity TON as the operating capacity TON1 (the

indoor units

20a, 20b, 20c, 20d are ON). In step S132, the controller 50 proceeds to step S133 after the predetermined time t3 has elapsed. In step S133, the controller 50 detects the operating capacity TON as the operating capacity TON2 (the indoor unit 20 is ON).

In step S134, if the operating capacity TON2 is smaller than the operating capacity TON1, the controller 50 proceeds to step S135. If the operating capacity TON2 is equal to or larger than the operating capacity TON1, the process returns to S131.

In step S135, the controller 50 sets the ratio of the operating capacity TON2 to the operating capacity TON1, that is, when the operating capacity change rate R as the changing rate of the operating capacity TON of the indoor unit 20 in the predetermined time t3 is the predetermined rate R3 or less. It transfers to step S136. If the operating capacity change rate R is larger than the predetermined rate R3, the process returns to S131.

In step S136, the controller 50 detects the high pressure HP by the high pressure sensor 62. In step S137, the controller 50 determines that the refrigerant is rapidly staying in the outdoor heat exchanger 12 when the high pressure HP is equal to or greater than the predetermined value HP3 set in advance, and proceeds to step S138. If the high pressure HP is less than the predetermined value HP3, the process returns to S131.

In step S138, the controller 50 detects the low pressure LP by the low pressure sensor 61. In step S139, the controller 50 calculates a differential pressure dP between the high pressure HP and the low pressure LP.

In step S140, the controller 50 calculates the condensation temperature Tc from the high pressure HP. In step S141, the controller 50 detects the outdoor heat exchanger outlet temperature Tco with the outdoor heat exchanger outlet temperature sensor 71. In step S142, the controller 50 calculates the degree of subcooling SC at the outlet of the outdoor heat exchanger 12 from the outdoor heat exchanger outlet temperature Tco and the condensation temperature Tc.

In step S143, the controller 50 increases the opening degree of the motor operated valve 21a by a predetermined amount ΔEv according to the differential pressure dP and the subcooling degree SC. Specifically, when the differential pressure dP and the degree of subcooling SC are large, the predetermined amount ΔEv to be increased is increased, and when the differential pressure dP and the degree of subcooling SC are small, the predetermined amount ΔEv to be increased is decreased. .

(3-6-2) Operation The operation of the motor-operated valve control S130 will be described with reference to FIG. In FIG. 10, regarding the operation of the motor-operated valve control S130, a time series of the operating capacity TON of the indoor unit 20, the high pressure HP, the differential pressure dP, the degree of subcooling SC of the outdoor heat exchanger 12, and the opening degree of the motored valve 21a It is expressed using change.

In step S131, the operating capacity TON is detected as the operating capacity TON1 (the

indoor units

20a, 20b, 20c, 20d are ON). After t3 has elapsed, at step S133, the operating capacity TON is detected as the operating capacity TON2 (the indoor unit 20a is ON).

In step S134, it is detected that the operating capacity TON2 is smaller than the operating capacity TON1. In step S135, it is detected that the operating capacity change rate R is equal to or less than a predetermined rate R3. At this time, in the air conditioning apparatus 100, it is determined that the operating capacity TON of the indoor unit 20 has rapidly decreased.

In step S137, it is detected that the high pressure Hp is greater than or equal to the predetermined value HP3, and it is determined that the refrigerant is rapidly staying in the outdoor heat exchanger 12. In step S143, the opening degree of the motor operated valve 21a is increased based on the differential pressure dP and the degree of subcooling SC.

At this time, in the air conditioning apparatus 100, the opening degree of the motor-operated valve 21a is increased, so that the refrigerant liquid rapidly staying in the outdoor heat exchanger 12 escapes from the outdoor heat exchanger 12. The refrigerant liquid staying in the outdoor heat exchanger 12 escapes from the outdoor heat exchanger 12, whereby the high pressure HP decreases (10a in FIG. 10).

(3-6-3) Effects In this manner, in the air conditioning apparatus 100, the refrigerant liquid that rapidly accumulates in the outdoor heat exchanger 12 can be released from the outdoor heat exchanger 12. At the same time, the operation of the high pressure shutoff pressure switch 82 can be avoided to prevent the air conditioner 100 from stopping.

(3-7) Compressor Operating Capacity Control at the Time of Increasing Operating Capacity The compressor operating capacity control S210 at the time of operating capacity increase will be described using FIG. 11 and FIG. The compressor operating capacity control S210 is control for suppressing the rise of the evaporation temperature Te when the operating capacity TON of the indoor unit 20 sharply increases and the evaporation temperature Te rises rapidly.

(3-7-1) Flow The flow of the compressor operating capacity control S210 will be described with reference to FIG. In order to make the explanation easy to understand, it is assumed that the

indoor units

20b, 20c and 20d are turned on from the state in which only the indoor unit 20a is turned on.

In step S211, the controller 50 detects the operating capacity TON of the indoor unit 20 as the operating capacity TON3 (the indoor unit 20a is ON). In step S212, the controller 50 proceeds to step S213 after the predetermined time t4 has elapsed. In step S213, the controller 50 detects the operating capacity TON as the operating capacity TON 4 (the

indoor units

20a, 20b, 20c, 20d are ON).

In step S214, when the operating capacity TON4 is larger than the operating capacity TON3, the controller 50 proceeds to step S215. If the operating capacity TON4 is less than or equal to the operating capacity TON3, the process returns to S211.

In step S215, the controller 50 sets the ratio of the operating capacity TON4 to the operating capacity TON3, that is, when the operating capacity change rate R as the changing rate of the operating capacity TON of the indoor unit 20 in the predetermined time t4 is the predetermined rate R4 or more. It is determined that the operating capacity TON of the indoor unit 20 has rapidly increased, and the process proceeds to step S216. If the operating capacity change rate R is smaller than the predetermined rate R4, the process returns to S211.

In step S216, the controller 50 detects the indoor suction air temperatures Taa, Tab, Tac, Tad by the indoor suction

air temperature sensors

73a, 73b, 73c, 73d. Here, the average value of the indoor suction air temperatures Taa, Tab, Tac, Tad of the

indoor units

20a, 20b, 20c, 20d being operated is taken as the indoor suction air temperature average Ta-ave.

In step S217, the controller 50 increases the operating capacity Cap of the compressor 11 by a predetermined amount ΔCap according to the increased operating capacity TON and the indoor suction air temperature average Ta-ave.

Here, the increased operating capacity TON is the operating capacity TON 4 detected in step S213.

Specifically, when the operating capacity TON and the indoor suction air temperature average Ta-ave are large, the predetermined amount ΔCap to be increased is large, and when the operating capacity TON and the indoor suction air temperature average Ta-ave are small, the increase is The predetermined amount ΔCap to be reduced is small.

That is, when the controller 50 determines that the operating capacity TON of the indoor unit 20 has rapidly increased, the compressor operating capacity control S200 during normal operation (the operating capacity Cap of the compressor 11 based on the evaporation temperature Te In addition to the control), the feed-forward control increases the operating capacity Cap of the compressor 11 according to the operating capacity TON and the indoor suction air temperature average Ta-ave.

(3-7-2) Operation The operation of the compressor operating capacity control S210 will be described with reference to FIG. In FIG. 12, the operation of the compressor operating capacity control S210 is expressed using time series changes of the operating capacity TON of the indoor unit 20, the indoor suction air temperature Ta, the operating capacity Cap of the compressor 11, and the evaporation temperature Te. There is.

In step 211, the operating capacity TON is detected as an operating capacity TON3 (the indoor unit 20a is ON). After t4 has elapsed, at step S213, the operating capacity TON is detected as the operating capacity TON4 (the

indoor units

20a, 20b, 20c, 20d are ON). At this time, in the air conditioning apparatus 100, it is determined that the operating capacity TON of the indoor unit 20 has rapidly increased.

In step 216, the indoor suction air temperature Ta is detected. In step S217, the operating capacity Cap of the compressor 11 is increased by a predetermined amount ΔCap based on the operating capacity TON and the indoor suction air temperature Ta.

At this time, in the air conditioning apparatus 100, the operating pressure Cap of the compressor 11 is increased by the predetermined amount ΔCap, so that the low pressure LP decreases and the increase of the evaporation temperature Te is suppressed (12a in FIG. 12). By suppressing the rise of the evaporation temperature Te, a decrease in the heat exchange efficiency of the indoor heat exchanger 22 is avoided.

(3-7-3) Effects In this manner, in the air conditioning apparatus 100, it is possible to avoid a decrease in the heat exchange efficiency of the indoor heat exchanger 22.

<Features>
(1)
In the air conditioning apparatus 100, excess refrigerant is generated when the operating capacity TON of the indoor unit 20 is small. The generated surplus refrigerant stagnates in the outdoor heat exchanger 12. For example, when the operating capacity Cap of the compressor 11 rapidly decreases (such as the number of operating indoor units 20 decreases) under high outside air, the refrigerant liquid rapidly stagnates in the outdoor heat exchanger 12.

When the refrigerant liquid rapidly stagnates in the outdoor heat exchanger 12, the high pressure HP of the air conditioner 100 rapidly rises. At this time, in the air conditioning apparatus 100, the operation of the high pressure protection control S300 may not catch up and the high pressure cutoff pressure switch 82 may operate. When the high pressure shutoff pressure switch 82 is operated, the air conditioner 100 is stopped.

The air conditioning apparatus 100 includes the plurality of indoor units 20, the compressor 11, and the outdoor heat, each of which includes the motor-operated valve 21 and the indoor heat exchanger 22, and the ON / OFF of the operation is individually operated. The controller 50 includes an outdoor unit 10 having an exchanger 12 and to which a plurality of indoor units 20 are connected, and a controller 50 for controlling the opening degree of the motor-operated valve 21. When the operating capacity TON decreases by a predetermined rate R3 for a predetermined time t3, the opening degree of the motor-operated valve 21 of the operating indoor unit 20 is increased.

With such a configuration, in the air conditioning apparatus 100, when the operating capacity TON of the indoor unit 20 decreases by the predetermined ratio R3 to the predetermined time t3, the opening degree of the motor-operated valve 21 is increased. At this time, the refrigerant liquid rapidly staying in the outdoor heat exchanger 12 flows from the outdoor heat exchanger 12 toward the indoor heat exchanger 22.

In this manner, in the air conditioning apparatus 100, the refrigerant liquid rapidly staying in the outdoor heat exchanger 12 can be released from the outdoor heat exchanger 12.

(2)
The air conditioning apparatus 100 includes the plurality of indoor units 20, the compressor 11, and the outdoor heat, each of which includes the motor-operated valve 21 and the indoor heat exchanger 22, and the ON / OFF of the operation is individually operated. The controller 50 includes an outdoor unit 10 having an exchanger 12 and to which a plurality of indoor units 20 are connected, and a controller 50 for controlling the opening degree of the motor-operated valve 21. When the operating capacity TON decreases by a predetermined rate during a predetermined time and the high pressure HP is equal to or higher than a predetermined value HP3 as a first predetermined value, the opening degree of the indoor unit 20 motor operated valve 21 is increase.

With such a configuration, in the air conditioning apparatus 100, when the operating capacity TON of the indoor unit 20 decreases by the predetermined rate R3 in the predetermined time t3, and the high pressure HP is the predetermined value HP3 or more, the electric motor The opening degree of the valve 21 is increased. At this time, the refrigerant liquid rapidly staying in the outdoor heat exchanger 12 flows from the outdoor heat exchanger 12 toward the indoor heat exchanger 22.

(3)
In the air conditioning apparatus 100, the controller 50 increases the opening degree of the motor-operated valve 21 according to the differential pressure dP between the high pressure HP and the low pressure LP when the operating capacity decreases.

With such a configuration, in the air conditioning apparatus 100, when the opening degree of the motor operated valve 21 is increased, it is increased according to the differential pressure dP between the high pressure H and the low pressure Lp.

(4)
In the air conditioning apparatus 100, the controller 50 increases the opening degree of the motor-operated valve 21 according to the degree SC of subcooling at the outlet of the outdoor heat exchanger 12 when the operating capacity decreases.

With such a configuration, in the air conditioning apparatus 100, when the opening degree of the motor operated valve 21 is increased, it is increased according to the subcooling degree SC of the outlet of the outdoor heat exchanger 12.

(5)
In the air conditioner 100, the controller 50 controls the opening degree of the motor-operated valve 21 so that the degree of superheat SH at the outlet of the indoor heat exchanger 22 becomes the target degree of superheat SHm during normal operation different from when the operating capacity decreases. Do.

With such a configuration, the air conditioning apparatus 100 is operated in the normal operation such that the degree of superheat SH of the indoor heat exchanger 22 becomes the target degree of superheat SHm.

Thus, in the air conditioning apparatus 100, the wet operation or the overheat operation of the compressor 11 can be prevented.

(6)
In the air conditioning apparatus 100, the controller 50 sets the opening degree of the motor-operated valve 21 to fully open when the operating capacity decreases.

With such a configuration, in the air conditioning apparatus 100, when the opening degree of the motor-operated valve 21 is increased, the opening degree of the motor-operated valve 21 is set to be fully open.

(7)
In the air conditioning apparatus 100, the controller 50 reduces the operating capacity Cap of the compressor 11 if the high pressure HP of the air conditioning apparatus 100 is equal to or higher than the predetermined value HPn as the second predetermined value.

With such a configuration, in the air conditioning apparatus 100, the high pressure HP is reduced before the high pressure shutoff pressure switch 82 operates.

Thus, in the air conditioning apparatus 100, the high pressure shutoff pressure switch 82 can be prevented from being operated and stopped.

(8)
The air conditioning apparatus 100 stops the compressor 11 if the high pressure pressure HP is equal to or higher than the predetermined value HPm as the third predetermined value.

Thus, the air conditioner 100 can prevent the piping or the container from being damaged.

(9)
The air conditioning apparatus 100 is a cooling dedicated apparatus and does not have a container for adjusting the amount of refrigerant.

<Modification>
(1)
In step S135 of the motor-operated valve control S130, when the controller 50 determines that the operating capacity change rate R is less than or equal to the predetermined rate R3, the refrigerant liquid rapidly stagnates in the condenser 12 and the high pressure HP rapidly The opening degree of the motor operated valve 21a may be increased in anticipation of rising.

(2)
When the controller 50 determines that the operating capacity change rate R is less than or equal to the predetermined rate R3 in steps s135 and S136 of the motor-operated valve control S130, the refrigerant liquid rapidly stagnates in the condenser 12 and the high pressure HP It is also possible to increase the degree of opening of the motor operated valve 21a in anticipation of a sudden rise.

(3)
In step S143 of the motor-operated valve control S130, the controller 50 increases the opening degree of the motor-operated valve 21a based on the differential pressure dP and the degree of subcooling SC. The opening degree of the valve 21a may be increased.

(4)
In step S143 of the motor-operated valve control S130, the controller 50 increases the opening degree of the motor-operated valve 21a based on the differential pressure dP and the degree of subcooling SC, but based on only the differential pressure dP, The degree of opening may be increased. Further, the opening degree of the motor operated valve 21a may be increased based on only the degree of supercooling SC.

In step S143 of the motor-operated valve control S130, the controller 50 increases the opening degree of the motor-operated valve 21a by a predetermined amount, but the opening degree of the motor-operated valve 21a may be fully opened.

The motor-operated valve control S130 is applied at the time of the cooling operation of the cooling-dedicated device, but may be applied at the heating operation of the air conditioning device capable of cooling and heating.

The present invention can be used for an air conditioner.

10: outdoor unit 11: compressor 12: outdoor heat exchanger (condenser)
13: Outdoor fan 20: Indoor unit 21: Motor-operated valve (expansion valve)
22: Indoor heat exchanger (evaporator)
31: Suction piping 32: Discharge piping 33: Liquid piping 50: Controller (control device)
61: low pressure sensor 62: high pressure sensor 71: outdoor heat exchanger outlet temperature sensor 72: indoor heat exchanger outlet temperature sensor 73: indoor suction air temperature sensor 74: outdoor suction air temperature sensor 82: high pressure shutoff pressure switch 100: Air conditioner

JP, 2015-124958, A

Claims

A plurality of indoor units (20), each having an expansion valve (21) and an evaporator (22), and the ON / OFF of the operation is individually operated.
An outdoor unit (10) having a compressor (11) and a condenser (12), to which a plurality of the indoor units (20) are connected;
A control device (50) for controlling an opening degree of the expansion valve (21);
Equipped with
The controller (50) is configured to control the expansion valve (21) of the indoor unit (20) during operation when the total operating capacity of the plurality of indoor units (20) decreases by a predetermined rate within a predetermined time. Air conditioner (100), which increases the opening degree of).
A plurality of indoor units (20), each having an expansion valve (21) and an evaporator (22), and the ON / OFF of the operation is individually operated.
An outdoor unit (10) having a compressor (11) and a condenser (12), to which a plurality of the indoor units (20) are connected;
A control device (50) for controlling an opening degree of the expansion valve (21);
Equipped with
The control device (50) is in operation when the operating capacity decreases when the total operating capacity of the plurality of indoor units (20) decreases by a predetermined rate in a predetermined time, and the high pressure is equal to or higher than a first predetermined value An air conditioner (100) for increasing the opening degree of the expansion valve (21) of the indoor unit (20).
The air conditioning according to claim 1 or 2, wherein the controller (50) increases the opening degree of the expansion valve (21) according to a differential pressure between a high pressure and a low pressure when the operating capacity decreases. Device (100).
The control device (50) increases the opening degree of the expansion valve (21) according to the degree of subcooling of the outlet of the condenser (12) when the operating capacity decreases. The air conditioner (100) according to any one of the preceding claims.
The controller (50) sets the degree of opening of the expansion valve (21) such that the degree of superheat at the outlet of the evaporator (22) becomes the target degree of superheat during normal operation different from when the operating capacity decreases. The air conditioner (100) according to any one of the preceding claims, wherein it is controlled.
The air conditioning apparatus (100) according to any one of claims 1 to 5, wherein the control device (50) sets the opening degree of the expansion valve (21) to fully open when the operating capacity decreases.
The air conditioner according to any one of claims 1 to 6, wherein the control device (50) reduces the operating capacity of the compressor (11) if the high pressure is equal to or higher than a second predetermined value. 100).
The air conditioner (100) according to any one of claims 1 to 7, wherein the control device (50) stops the compressor (11) if the high pressure is equal to or higher than a third predetermined value.
The air conditioning apparatus (100) according to any one of claims 1 to 8, which is a cooling-dedicated apparatus and does not have a container for adjusting the amount of refrigerant.