JPWO2019087407A1 - Air conditioner - Google Patents

Abstract

Provided is an air conditioner capable of allowing a refrigerant liquid rapidly staying in a condenser to escape from the condenser. The air conditioner (100) has an electric valve (21) and an indoor heat exchanger (22), respectively, and has a plurality of indoor units (20) whose operation is individually turned on or off. The opening degree of the outdoor unit (10) having the compressor (11) and the outdoor heat exchanger (12) and to which the plurality of indoor units (20) are connected and the expansion valve (21). A control device (50) for controlling is provided, and the control device (50) is in operation when the total operating capacity of the plurality of indoor units (20) is reduced by a predetermined rate in a predetermined time. The opening degree of the expansion valve (21) of the indoor unit (20) is increased.

Description

The present invention relates to an air conditioner.

Conventionally, an air conditioner including a refrigerant circuit in which a compressor, a condenser, an electric valve, and an evaporator are connected is known. Patent Document 1 (Japanese Unexamined Patent Publication No. 2015-12495) describes an air conditioner that reduces the fan speed of an indoor unit when a low pressure exceeds an upper limit value during cooling operation under high outside air. ing.

However, Patent Document 1 (Japanese Unexamined Patent Publication No. 2015-124958) describes a refrigerant liquid that rapidly stays in the condenser when the high pressure pressure rises sharply during the cooling operation under high outside air. There is no mention of letting it escape from the condenser. An object of the present disclosure is to let the refrigerant liquid rapidly staying in the condenser escape from the condenser.

The air conditioner according to the first aspect of the present disclosure has a plurality of indoor units, a compressor, and a condenser, each of which has an expansion valve and an evaporator, and whose operation can be turned ON or OFF individually. The outdoor unit is provided with a device, an outdoor unit to which a plurality of indoor units are connected, and a control device for controlling the opening degree of the expansion valve. The control device has a total operating capacity of the plurality of indoor units for a predetermined time. When the operating capacity is reduced by a predetermined rate, the opening degree of the expansion valve of the indoor unit during operation is increased.

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

The air conditioner according to the second aspect of the present disclosure has a plurality of indoor units, a compressor, and a condenser, each of which has an expansion valve and an evaporator, and whose operation can be turned ON or OFF individually. The outdoor unit is provided with a device, an outdoor unit to which a plurality of indoor units are connected, and a control device for controlling the opening degree of the expansion valve. The control device has a total operating capacity of the plurality of indoor units at a predetermined time. When the operating capacity is reduced by a predetermined rate and the high-pressure pressure is equal to or higher than the first predetermined value, the opening degree of the expansion valve of the indoor unit during operation 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 is reduced.

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 supercooling at the outlet of the condenser when the operating capacity is reduced.

In the air conditioner according to the fifth aspect of the present disclosure, the control device adjusts the opening degree of the expansion valve so that the superheat degree at the outlet of the evaporator becomes the target superheat degree during normal operation, which is different from when the operating capacity is increased or decreased. 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 fully open when the operating capacity is reduced.

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

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

It is a refrigerant system diagram of an air conditioner. It is a flowchart of the motorized valve control at the time of a 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 the motorized valve control when the refrigerant stays. It is also a time chart. It is a flowchart of the motorized valve control at the time of high pressure rise. It is also a time chart. It is a flowchart of the motorized valve control when the operating capacity is reduced. It is also a time chart. It is a flowchart of compressor capacity control when the operating capacity increases. It is also a time chart.

Hereinafter, embodiments of the air conditioner 100 according to the present disclosure will be described with reference to the drawings. The specific configuration of the air conditioner 100 according to the present disclosure is not limited to the following embodiments, and can be changed without departing from the gist of the disclosure.

<Air conditioner>
(1) Overall Configuration The overall configuration of the air conditioner 100 will be described with reference to FIG. The dashed line in FIG. 1 represents an electrical signal line. In the following, the upstream side or the downstream side is defined according to the flow direction of the refrigerant.

The air conditioner 100 is a device that cools a room such as a building by using a vapor compression refrigeration cycle. The air conditioner 100 is a dedicated cooling device. The air conditioner 100 includes an outdoor unit 10, four indoor units 20a, 20b, 20c, 20d, connecting pipes 41, 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 housed in an outdoor casing (not shown).

The compressor 11 sends out the refrigerant gas from a low pressure to a high pressure. A suction pipe 31 is connected to the low pressure side of the compressor 11. A low-pressure 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 pressure sensor 62 and a high-pressure cutoff 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 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 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 pressure sensor 62 detects the refrigerant gas compressed by the compressor 11, that is, the high-pressure 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 cutoff pressure switch 82 stops the air-conditioning device 100 when the high-pressure pressure HP of the air-conditioning device 100 is equal to or higher than a predetermined value HPm.

(1-2) Indoor unit The indoor unit 20a is provided inside the building. The indoor unit 20a is connected to the outdoor unit 10 by a connecting 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 motorized valve 21a, the indoor heat exchanger 22a, and the indoor fan 23a are housed in an indoor casing (not shown).

The motor-operated valve 21a expands the refrigerant liquid into a gas-liquid mixed refrigerant. The motorized valve 21a is electrically driven and is operated to increase or decrease the opening degree. The upstream side of the motorized valve 21a is connected to the connecting pipe 41.

The indoor heat exchanger 22a exchanges heat between air and a refrigerant to evaporate the gas-liquid mixed refrigerant into a refrigerant gas. The downstream side of the indoor heat exchanger 22a is connected to the connecting 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 controller 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 (indoor heat exchanger outlet temperature Too). The indoor suction air temperature sensor 73a detects the indoor suction air temperature Ta of the indoor unit 20a.

Since the indoor units 20b, 20c, and 20d have the same configuration as the indoor unit 20a, the description thereof will be omitted. In the following, when the indoor units 20a, 20b, 20c, and 20d are arbitrarily represented, the indoor unit 20 is simply used. The same applies to the motorized 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 and a control board (not shown) provided on the indoor units 20a, 20b, 20c, and 20d, which are connected to each other so as to be able to communicate with each other by wire or wirelessly. It is configured to have. Further, the controller 50 includes one or more CPUs, ROMs, RAMs, and the like.

The controller 50 includes a low pressure sensor 61, a high pressure pressure sensor 62, a high pressure breaking pressure switch 82, an outdoor heat exchanger outlet temperature sensor 71, an electric valve 21, an indoor heat exchanger outlet temperature sensor 72, and indoor suction. It is connected to the air temperature sensor 73 and the remote control of the indoor unit 20.

The controller 50 has a function of changing the rotation 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 motorized 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 that is being operated (thermo ON). In the operating capacity TON, the capacity of the indoor unit 20 whose thermostat is turned 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) Connecting pipes The connecting pipes 41 and 42 connect the outdoor unit 10 and the plurality of indoor units 20a, 20b, 20c, and 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 air and condensed in the refrigerant liquid. The condensed refrigerant liquid flows toward the motorized valve 21a.

The refrigerant liquid is expanded into a gas-liquid mixed refrigerant by the electric 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 heated by air and evaporated into the refrigerant gas. The evaporated refrigerant gas is sucked into the compressor 11.

(3-1) Solenoid valve control during normal operation The motorized valve control S100 during normal operation will be described with reference to FIG. The normal operation is a cooling operation, which is different from the control when the refrigerant stays, the high pressure rises, and the operating capacity decreases, which will be described later. In order to make the explanation easier 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 Too 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 Too and the evaporation temperature Te. In step S105, the controller 50 reduces the opening degree of the motor-operated valve 21a when the superheat degree SH is smaller than the preset target superheat degree SHm. On the other hand, the controller 50 increases the opening degree of the motorized valve 21a when the superheat degree SH is larger than the target superheat degree SHm.

With such a configuration, the air conditioner 100 is operated so that the superheat degree SH of the indoor heat exchanger 22a becomes the target superheat degree SHm during normal operation. In this way, the air conditioner 100 can avoid the wet operation or the overheating operation of the compressor 11.

(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 easier 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 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 controller.

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 when the difference between the indoor suction air temperature Ta and the set temperature Ts is small. Decreases the operating capacity Cap.

With such a configuration, in the air conditioner 100, the operating capacity Cap of the compressor 11 is controlled so that the indoor suction air temperature Ta approaches the set temperature Ts during normal operation. In this way, the air conditioner 100 executes the capacity control of the compressor 11 suitable for the heat load, and can quickly set the indoor suction air temperature Ta to the set temperature Ts.

As a modification of the compressor operating capacity control S200 during normal operation, the operating capacity Cap of the compressor 11 may be controlled so 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 Voltage Protection Control The high voltage 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 or not the high pressure pressure HP is larger than the predetermined value HPn. The predetermined value HPn is smaller than the predetermined value HPm set by the high voltage cutoff pressure switch 82.

In step S302, if the high pressure pressure HP is larger than the predetermined value HPn, the process proceeds to step S303. When the high pressure pressure HP is equal to or less than 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 conditioner 100, even when the high-voltage pressure HP rises, the high-voltage pressure HP decreases before the high-voltage cutoff pressure switch 82 operates. In this way, in the air conditioner 100, it is possible to prevent the high voltage cutoff pressure switch 82 from being operated and stopped.

(3-4) Solenoid valve control when refrigerant stays The motor valve control S110 when refrigerant stays will be described with reference to FIGS. 5 and 6. The motor-operated valve control S110 is a control for ensuring 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 addition, in order to make the explanation easy to understand, it is assumed that the indoor units 20b, 20c, and 20d are turned off.

In step S111, the controller 50 detects the outdoor heat exchanger outlet temperature Tco by 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 supercooling degree SC of 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 shifts to step S116 when the condensation temperature Tc is equal to or higher than the preset predetermined temperature Tc1. If the condensation temperature Tc is less than the predetermined temperature Tc1, the process returns to S111.

In step S116, the controller 50 shifts to step S117 when the supercooling degree SC is equal to or higher than the preset predetermined value SC1. If the supercooling degree SC is less than the predetermined value SC1, the process returns to S111. In step S117 (when the refrigerant stays), the controller 50 determines that the refrigerant liquid stays in the outdoor heat exchanger 12, and sets the target superheat degree SHm in the motorized valve control S100 low.

(3-4-2) Action The action of the motor-operated valve control S110 will be described with reference to FIG. In FIG. 6, regarding the operation of the solenoid valve control S110, the condensation temperature Tc, the supercooling degree SC at the outlet of the outdoor heat exchanger 12, the target superheating degree SHm of the indoor heat exchanger 22a, the opening degree and compression of the solenoid valve 21a. It is expressed using the time-series change of the operating capacity Cap of the machine 11.

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

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

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

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

(3-4-3) Effect In this way, in the air conditioner 100, the refrigerant liquid staying in the outdoor heat exchanger 12 can be released from the outdoor heat exchanger 12. At the same time, in the air conditioner 100, the high pressure protection control S300 can be avoided, and a decrease in the cooling capacity can be avoided.

(3-5) Solenoid valve control when high pressure rises The motorized valve control S120 when high pressure rises will be described with reference to FIGS. 7 and 8. The motor-operated valve control S120 is a control that prevents the air conditioner 100 from being stopped by the high-pressure breaking pressure switch 82 when the high-pressure pressure HP suddenly 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. 7. In addition, in order to make the explanation easy to understand, it is assumed that the indoor units 20b, 20c, and 20d are 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 shifts to step S123 when the high pressure pressure HP is equal to or higher than the preset predetermined value HP2. If the high pressure pressure HP is less than the predetermined value HP2, the process returns to S121.

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

In step S124 (when the high pressure rises), the controller 50 determines that the refrigerant is rapidly retained in the outdoor heat exchanger 12, and increases the opening degree of the motorized valve 21a by a predetermined amount. In step S125, the controller 50 reduces the operating capacity Cap of the compressor 11 by a predetermined amount.

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

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

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

(3-5-3) Effect In this way, in the air conditioner 100, the refrigerant liquid that rapidly stays in the outdoor heat exchanger 12 can be released from the outdoor heat exchanger 12. At the same time, the air conditioner 100 can avoid the operation of the high voltage cutoff pressure switch 82 and prevent the air conditioner 100 from stopping.

(3-6) Solenoid valve control when operating capacity decreases>
The motor-operated valve control S130 when the operating capacity is reduced will be described with reference to FIGS. 9 and 10. The motor-operated valve control S130 is a control for avoiding the stoppage of the air conditioner 100 when the operating capacity TON of the indoor unit 20 suddenly decreases and the high-pressure pressure HP suddenly rises.

(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 explanation easier to understand, it will be described that the indoor units 20b, 20c, 20d are turned off from the state where the indoor units 20a, 20b, 20c, and 20d are turned on.

In step S131, the controller 50 detects the operating capacity TON as the operating capacity TON1 (indoor units 20a, 20b, 20c, 20d are ON). In step S132, the controller 50 shifts 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, when the operating capacity TON2 is smaller than the operating capacity TON1, the controller 50 shifts to step S135. When the operating capacity TON2 is equal to or larger than the operating capacity TON1, the process returns to S131.

In step S135, when the ratio of the operating capacity TON2 to the operating capacity TON1, that is, the operating capacity change rate R as the rate of change of the operating capacity TON of the indoor unit 20 in the predetermined time t3 is equal to or less than the predetermined rate R3, The process proceeds to step S136. When 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, when the high-pressure pressure HP is equal to or higher than the preset predetermined value HP3, the controller 50 determines that the refrigerant is rapidly accumulated in the outdoor heat exchanger 12, and proceeds to step S138. If the high pressure 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 the 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 by the outdoor heat exchanger outlet temperature sensor 71. In step S142, the controller 50 calculates the supercooling degree SC of 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 electric valve 21a by a predetermined amount ΔEv according to the differential pressure dP and the supercooling degree SC. Specifically, when the differential pressure dP and the supercooling degree SC are large, the increasing predetermined amount ΔEv is increased, and when the differential pressure dP and the supercooling degree SC are small, the increasing predetermined amount ΔEv is decreased. ..

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

In step S131, the operating capacity TON is detected as the operating capacity TON1 (indoor units 20a, 20b, 20c, 20d are ON). After t3 has elapsed, in step S133, the operating capacity TON is detected as the operating capacity TON2 (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, the operating capacity change rate R is detected as a predetermined rate R3 or less. At this time, in the air conditioner 100, it is determined that the operating capacity TON of the indoor unit 20 has decreased sharply.

In step S137, it is detected that the high-pressure pressure HP is equal to or higher than the predetermined value HP3, and it is determined that the refrigerant is rapidly retained in the outdoor heat exchanger 12. In step S143, the opening degree of the motorized valve 21a is increased based on the differential pressure dP and the supercooling degree SC.

At this time, in the air conditioner 100, the opening degree of the motorized 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 high-pressure pressure HP decreases as the refrigerant liquid staying in the outdoor heat exchanger 12 escapes from the outdoor heat exchanger 12 (10a in FIG. 10).

(3-6-3) Effect In this way, in the air conditioner 100, the refrigerant liquid that rapidly stays in the outdoor heat exchanger 12 can be released from the outdoor heat exchanger 12. At the same time, it is possible to avoid the operation of the high-voltage cutoff pressure switch 82 and prevent the air conditioner 100 from stopping.

(3-7) Compressor Operating Capacity Control When Operating Capacity Increases The compressor operating capacity control S210 when operating capacity increases will be described with reference to FIGS. 11 and 12. The compressor operating capacity control S210 is a control that suppresses an increase in the evaporation temperature Te when the operating capacity TON of the indoor unit 20 suddenly increases and the evaporation temperature Te rises sharply.

(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 easier to understand, it is assumed that the indoor units 20b, 20c, and 20d are turned on from the state where 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 shifts 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 TON4 (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 shifts to step S215. When the operating capacity TON4 is equal to or less than the operating capacity TON3, the process returns to S211.

In step S215, when the ratio of the operating capacity TON4 to the operating capacity TON3, that is, the operating capacity change rate R as the rate of change 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 increased sharply, 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, and Tad by the indoor suction air temperature sensors 73a, 73b, 73c, and 73d. Here, the average value of the indoor suction air temperatures Taa, Tab, Tac, and Tad of the indoor units 20a, 20b, 20c, and 20d being operated is defined 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 T-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 T-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 T-ave are small, it increases. The predetermined amount ΔCap to be made is small.

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

(3-7-2) Action The action 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 represented by using the 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 the operating capacity TON3 (indoor unit 20a is ON). After t4 has elapsed, in step S213, the operating capacity TON is detected as the operating capacity TON4 (indoor units 20a, 20b, 20c, 20d are ON). At this time, in the air conditioner 100, it is determined that the operating capacity TON of the indoor unit 20 has increased sharply.

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 conditioner 100, the operating capacity Cap of the compressor 11 is increased by a predetermined amount ΔCap, so that the low pressure LP is lowered and the increase in the evaporation temperature Te is suppressed (12a in FIG. 12). By suppressing the increase in the evaporation temperature Te, it is possible to avoid a decrease in the heat exchange efficiency of the indoor heat exchanger 22.

(3-7-3) Effect In this way, in the air conditioner 100, it is possible to avoid a decrease in the heat exchange efficiency of the indoor heat exchanger 22.

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

When the refrigerant liquid suddenly stays in the outdoor heat exchanger 12, the high pressure HP of the air conditioner 100 suddenly rises. At this time, in the air conditioner 100, the high-voltage cutoff pressure switch 82 may operate because the operation of the high-voltage protection control S300 cannot catch up. When the high-voltage cutoff pressure switch 82 is activated, the air conditioner 100 is stopped.

The air conditioner 100 has a plurality of indoor units 20, a compressor 11, and outdoor heat, each of which has an electric valve 21 and an indoor heat exchanger 22 and whose operation can be turned ON or OFF individually. An outdoor unit 10 having a exchanger 12 and to which a plurality of indoor units 20 are connected, and a controller 50 for controlling the opening degree of the electric valve 21 are provided, and the controller 50 is the entire plurality of indoor units 20. When the operating capacity TON is reduced by a predetermined rate R3 at a predetermined time t3, the opening degree of the electric valve 21 of the indoor unit 20 during operation is increased.

With such a configuration, in the air conditioner 100, when the operating capacity TON of the indoor unit 20 decreases by a predetermined rate R3 in a predetermined time t3, the opening degree of the motorized valve 21 is increased. At this time, the refrigerant liquid that rapidly stays in the outdoor heat exchanger 12 flows from the outdoor heat exchanger 12 toward the indoor heat exchanger 22.

In this way, in the air conditioner 100, the refrigerant liquid that rapidly stays in the outdoor heat exchanger 12 can be released from the outdoor heat exchanger 12.

(2)
The air conditioner 100 has a plurality of indoor units 20, a compressor 11, and outdoor heat, each of which has an electric valve 21 and an indoor heat exchanger 22 and whose operation can be turned ON or OFF individually. An outdoor unit 10 having a exchanger 12 and to which a plurality of indoor units 20 are connected, and a controller 50 for controlling the opening degree of the electric valve 21 are provided, and the controller 50 is the entire plurality of indoor units 20. When the operating capacity TON is reduced by a predetermined rate in a predetermined time and the high pressure pressure HP is equal to or higher than the predetermined value HP3 as the first predetermined value, the opening degree of the indoor unit 20 electric valve 21 during operation is adjusted. increase.

With such a configuration, in the air conditioner 100, when the operating capacity TON of the indoor unit 20 is reduced by a predetermined rate R3 at a predetermined time t3 and the high voltage pressure HP is a predetermined value HP3 or more, it is electrically operated. The opening degree of the valve 21 is increased. At this time, the refrigerant liquid that rapidly stays in the outdoor heat exchanger 12 flows from the outdoor heat exchanger 12 toward the indoor heat exchanger 22.

In this way, in the air conditioner 100, the refrigerant liquid that rapidly stays in the outdoor heat exchanger 12 can be released from the outdoor heat exchanger 12.

(3)
In the air conditioner 100, the controller 50 increases the opening degree of the motorized valve 21 according to the differential pressure dP between the high pressure HP and the low pressure LP when the operating capacity is reduced.

With such a configuration, in the air conditioner 100, when the opening degree of the electric valve 21 is increased, it is increased according to the differential pressure dP between the high pressure HP and the low pressure LP.

In this way, in the air conditioner 100, the refrigerant liquid that rapidly stays in the outdoor heat exchanger 12 can be released from the outdoor heat exchanger 12.

(4)
In the air conditioner 100, the controller 50 increases the opening degree of the motorized valve 21 according to the degree of supercooling SC at the outlet of the outdoor heat exchanger 12 when the operating capacity is reduced.

With such a configuration, in the air conditioner 100, when the opening degree of the motorized valve 21 is increased, it is increased according to the supercooling degree SC at the outlet of the outdoor heat exchanger 12.

In this way, in the air conditioner 100, the refrigerant liquid that rapidly stays in the outdoor heat exchanger 12 can be released from the outdoor heat exchanger 12.

(5)
In the air conditioner 100, the controller 50 controls the opening degree of the motorized valve 21 so that the superheat degree SH at the outlet of the indoor heat exchanger 22 becomes the target superheat degree SHm during normal operation, which is different from the time when the operating capacity is reduced. To do.

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

In this way, the air conditioner 100 can prevent the compressor 11 from getting wet or overheating.

(6)
In the air conditioner 100, the controller 50 sets the opening degree of the motorized valve 21 to fully open when the operating capacity is reduced.

With such a configuration, in the air conditioner 100, when the opening degree of the electric valve 21 is increased, the opening degree of the electric valve 21 is set to fully open.

In this way, in the air conditioner 100, the refrigerant liquid that rapidly stays in the outdoor heat exchanger 12 can be released from the outdoor heat exchanger 12.

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

With such a configuration, in the air conditioner 100, the high pressure HP is lowered before the high pressure cutoff pressure switch 82 is operated.

In this way, in the air conditioner 100, it is possible to prevent the high voltage cutoff pressure switch 82 from operating and being stopped.

(8)
In the air conditioner 100, the controller 50 stops the compressor 11 when the high pressure pressure HP is equal to or higher than the predetermined value HPm as the third predetermined value.

In this way, the air conditioner 100 can prevent the piping or the container from being damaged.

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

<Modification example>
(1)
In step S135 of the motorized valve control S130, when the controller 50 determines that the operating capacity change rate R is a predetermined rate R3 or less, the refrigerant liquid suddenly stays in the condenser 12, and the high pressure HP suddenly increases. The opening degree of the motorized valve 21a may be increased in anticipation of an increase.

(2)
In steps s135 and S136 of the motorized valve control S130, when the controller 50 determines that the operating capacity change rate R is a predetermined rate R3 or less, the refrigerant liquid suddenly stays in the condenser 12 and the high pressure HP You may increase the opening degree of the motor-operated valve 21a in anticipation that

(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 supercooling degree SC. For example, the motor-operated valve 21a is electrically operated according to the operating capacity change rate R. 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 supercooling degree SC, but the motor-operated valve 21a is increased based only on the differential pressure dP. The opening degree may be increased. Further, the opening degree of the motorized valve 21a may be increased based only on the supercooling degree 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 of the motor-operated valve 21a may be fully opened.

The motorized valve control S130 is applied during the cooling operation of the cooling dedicated device, but may be applied during the heating operation of the air conditioner capable of heating and cooling.

The present invention can be used in an air conditioner.

10: Outdoor unit 11: Compressor 12: Outdoor heat exchanger (condenser)
13: Outdoor fan 20: Indoor unit 21: Electric valve (expansion valve)
22: Indoor heat exchanger (evaporator)
31: Suction pipe 32: Discharge pipe 33: Liquid pipe 50: Controller (control device)
61: Low pressure pressure sensor 62: High pressure 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 breaking pressure switch 100: Air conditioner

JP-A-2015-12495

Claims (9)

A plurality of indoor units (20) having an expansion valve (21) and an evaporator (22), respectively, and operating ON or OFF of operation individually.
An outdoor unit (10) having a compressor (11) and a condenser (12) and to which a plurality of the indoor units (20) are connected.
A control device (50) that controls the opening degree of the expansion valve (21), and
With
The control device (50) has the expansion valve (21) of the indoor unit (20) being operated when the total operating capacity of the plurality of indoor units (20) is reduced by a predetermined rate in a predetermined time. ), An air conditioner (100). A plurality of indoor units (20) having an expansion valve (21) and an evaporator (22), respectively, and operating ON or OFF of operation individually.
An outdoor unit (10) having a compressor (11) and a condenser (12) and to which a plurality of the indoor units (20) are connected.
A control device (50) that controls the opening degree of the expansion valve (21), and
With
The control device (50) is in operation when the total operating capacity of the plurality of indoor units (20) is reduced by a predetermined rate in a predetermined time and the high pressure is equal to or higher than the first predetermined value. An air conditioner (100) that increases the opening degree of the expansion valve (21) of the indoor unit (20). The air conditioning according to claim 1 or 2, wherein the control device (50) increases the opening degree of the expansion valve (21) according to the differential pressure between the high pressure pressure and the low pressure pressure when the operating capacity is reduced. Device (100). Any of claims 1 to 3, wherein the control device (50) increases the opening degree of the expansion valve (21) according to the degree of supercooling at the outlet of the condenser (12) when the operating capacity is reduced. The air conditioner (100) according to item 1. The control device (50) adjusts the opening degree of the expansion valve (21) so that the degree of superheat at the outlet of the evaporator (22) becomes the target degree of superheat during normal operation different from that when the operating capacity is reduced. The air conditioner (100) according to any one of claims 1 to 4, which is controlled. The air conditioner (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 is reduced. The air conditioner (50) according to any one of claims 1 to 6, wherein the control device (50) reduces the operating capacity of the compressor (11) when the high pressure pressure is equal to or higher than the 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) when the high pressure pressure is equal to or higher than a third predetermined value. The air conditioner (100) according to any one of claims 1 to 8, which is a dedicated cooling device and does not have a container for adjusting the amount of refrigerant.

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