WO2020111200A1

WO2020111200A1 - Air conditioning device

Info

Publication number: WO2020111200A1
Application number: PCT/JP2019/046651
Authority: WO
Inventors: 淳上重; 泰久菊池; 智子杉崎
Original assignee: 東芝キヤリア株式会社
Priority date: 2018-11-29
Filing date: 2019-11-28
Publication date: 2020-06-04
Also published as: EP3889522A4; JPWO2020111200A1; JP7098751B2; EP3889522A1; CN113167518A; CN113167518B

Abstract

When defrost operation is initiated in any one of a plurality of air conditioners, the defrost initiation conditions are modified for the other air conditioners apart from the air conditioner that has initiated defrost operation.

Description

Air conditioner

The present invention relates to an air conditioner including a plurality of air conditioners.

An air conditioner that has a heat pump type refrigeration cycle that circulates a refrigerant by sequentially connecting a compressor, a four-way valve, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger to heat indoor air by pumping heat from the outside air With the progress of heating, frost gradually adheres to the surface of the outdoor heat exchanger functioning as an evaporator, and when the amount of frost increases, the amount of heat pumped from the outside air decreases and the heating capacity decreases.

As a countermeasure, the frosted state of the outdoor heat exchanger is monitored from the temperature of the outdoor heat exchanger, and when the frost increases, the refrigerant discharged from the compressor (high temperature refrigerant) is directly supplied to the outdoor heat exchanger. The defrosting operation of defrosting the outdoor heat exchanger by the heat of the high-temperature refrigerant is executed.

JP, 2010-121798, A

In the case of an air conditioner that air-conditions the same air-conditioned area with a plurality of air conditioners, if a plurality of air conditioners enter defrosting operation at the same time, the heating capacity tends to be insufficient and the indoor temperature of the air-conditioned area drops, May cause discomfort to residents.

The purpose of this embodiment is to provide an air conditioner that can suppress a decrease in indoor temperature due to defrosting as much as possible.

The air conditioner according to claim 1 includes a heat pump type refrigeration cycle including a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducer, and an indoor heat exchanger, and when the defrosting start condition of the outdoor heat exchanger is satisfied. A plurality of air conditioners that perform defrosting operation on the outdoor heat exchanger; and when defrosting of one of these air conditioners is started, the remaining air conditioners other than the air conditioner that starts defrosting are removed. And a controller that changes the frost start condition.

The figure which shows the structure of one Embodiment. 6 is a flowchart showing control executed by the parent device in one embodiment regarding communication with the child device. 6 is a flowchart showing the control executed by each of the master unit and the slave unit in the embodiment. The figure which shows the execution of the defrosting operation|movement of each air conditioner in one Embodiment, and the change of the defrosting start condition accompanying the execution.

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, indoor units 20 of a plurality of

air conditioners

1a, 1b,... 1n that constitute an air conditioner are arranged in the same air conditioning area R.

The air conditioner 1a, which is a master unit, has a heat pump type refrigeration cycle in which a compressor 11, a four-way valve 12, an outdoor heat exchanger 13, a pressure reducer such as an electric expansion valve 14, and an indoor heat exchanger 21 are sequentially connected by piping. Prepare

During the cooling operation, the refrigerant discharged from the compressor 11 flows into the outdoor heat exchanger (condenser) 13 through the four-way valve 12, and the refrigerant flowing out of the outdoor heat exchanger 13 passes through the electric expansion valve 14. The refrigerant flowing into the indoor heat exchanger (evaporator) 21 and flowing out of the indoor heat exchanger 21 is sucked into the compressor 11 through the four-way valve 12.

During the heating operation, by switching the flow path of the four-way valve 12, the refrigerant discharged from the compressor 11 flows into the indoor heat exchanger (condenser) 21 through the four-way valve 12 as shown by the arrow. The refrigerant flowing out of the indoor heat exchanger 21 flows into the outdoor heat exchanger (evaporator) 13 through the electric expansion valve 14, and the refrigerant flowing out of the outdoor heat exchanger 13 passes through the four-way valve 12 and the compressor 11 Is sucked into. During the defrosting operation on the outdoor heat exchanger 13 during the heating operation, the return of the flow path of the four-way valve 12 forms the same refrigerant flow as during the cooling operation.

An outdoor fan 15 that sucks outside air and passes it through the outdoor heat exchanger 13 is arranged near the outdoor heat exchanger 13, and an outside air temperature sensor 16 that detects the outside air temperature To is arranged in the suction air passage of the outdoor fan 15. An indoor fan 22 that draws in the indoor air in the air-conditioned area and passes through the indoor heat exchanger 21 is arranged near the indoor heat exchanger 21, and an indoor temperature sensor 23 that detects the temperature Ta of the indoor air (referred to as the indoor temperature) is an indoor fan. 22 are arranged in the suction air passage.

The compressor 11, the four-way valve 12, the outdoor heat exchanger 13, the electric expansion valve 14, the outdoor fan 15, and the outdoor air temperature sensor 16 are housed in the outdoor unit 10 together with the outdoor controller 18a, and the indoor unit 21, the indoor fan 22, and the indoor unit are installed. The temperature sensor 23 is housed in the indoor unit 20 together with the indoor controller 24a. The outdoor controller 18a and the indoor controller 24a are connected to each other through a serial signal line 31 synchronized with the power supply voltage, and the indoor controller 24a has a remote control type operation device (abbreviated as a remote controller) for driving operation and setting operating conditions. ) 33 is connected via the cable 32. The remote controller 33 is attached to the wall surface or the like of the air-conditioned area and can be easily operated by the user.

The outdoor controller 18a includes a microcomputer and its peripheral circuits, controls the compressor 11, the four-way valve 12, the electric expansion valve 14, the outdoor fan 15 in accordance with an instruction from the indoor controller 24a, and detects the outside air temperature sensor 16. Data such as a temperature (referred to as outside air temperature) To and a temperature detected by the heat exchange temperature sensor 17 (referred to as heat exchanger temperature) Te are sent to the indoor controller 24a via the serial signal line 31.

The indoor controller 24a is composed of a microcomputer and its peripheral circuits, and controls the operation of the air conditioner 1a according to the operation of the remote controller 33, the operating conditions set by the remote controller 33, the transmission data from the outdoor controller 18a, and the like. In addition, the indoor controller 24a stores the defrosting start condition for the outdoor heat exchanger 13 in the internal memory in advance, and executes the defrosting operation for the outdoor heat exchanger 13 when the defrosting start condition is satisfied.

The defrosting start condition is a reference value Teo that is determined according to the heat exchanger temperature Te of the outdoor heat exchanger 13 (the temperature detected by the heat exchange temperature sensor 17) and the heat exchanger temperature Te of the outdoor heat exchanger 13 at the start of heating. The first defrosting start condition that the difference ΔTe (=Teo-Te) with the threshold value A is equal to or larger than the threshold value A, and the heat exchanger temperature Te of the outdoor heat exchanger 13 after a certain time t2 from the start of heating is a predetermined limit. The second defrosting start condition of less than the value Tex is included. The threshold value A is a value selected according to the outside air temperature To. For example, 6° C. is selected when To≧0° C. and 4° C. is selected when 0° C.≧To≧−10° C. When <-10°C, 2°C is selected, for example.

A bus line 40 for control and data transmission is connected between the indoor controller 24a and the indoor controllers 24b to 24n.

The air conditioners 1b to 1n are the same as the air conditioner 1a except that the air conditioners 1b to 1n have outdoor controllers 18b to 24n and indoor controllers 24b to 24n.

The indoor controllers 24b to 24n are composed of a microcomputer and its peripheral circuits, and comprehensively control the operation of each air conditioner in accordance with transmission data from the outdoor controllers 18b to 18n and instructions from the indoor controller 24a.

In addition, the indoor controllers 24b to 24n store the defrosting start condition for each outdoor heat exchanger 13 in the internal memory in advance, and when the defrosting start condition is satisfied, the defrosting operation for each outdoor heat exchanger 13 is performed. The frost operation is executed together with the outdoor controllers 18b-18n. The defrosting start condition is the same as the defrosting start condition of the indoor controller 24a (first defrosting start condition and second defrosting start condition).

When the group control mode for controlling the

air conditioners

1a, 1b,... 1n as one group is set by the remote controller 33, the air conditioner 1a and the indoor controller 24a function as the master unit that serves as the center of control, and the rest. The air conditioners 1b to 1n and the indoor controllers 24b to 24n function as slave units in accordance with instructions from the master unit.

The indoor controller 24a of the air conditioner 1a includes a first control unit C1, a second control unit C2, a third control unit C3, and a fourth control unit C4 as main functions related to the coordination between the master unit and the slave units.

The first control unit C1 executes mutual communication between the indoor controllers 24a to 24n via the data bus line 40 periodically and as needed. Through this communication, it is possible for the master unit and the slave unit to recognize each other whether or not the defrosting start condition is satisfied, the operating state, and the like.

When the defrosting start condition of one of the air conditioners 1a to 1n is satisfied and the air conditioner starts the defrosting operation, the second control unit C2 starts the defrosting. Machines (air conditioners for which the defrosting start condition has been satisfied) except for the air conditioners are changed to a direction ("defrosting" mode) in which the establishment of the air conditioner is delayed than usual.

After changing the delay direction by the second control unit C2, the third control unit C3 delays the delay when the air conditioner that satisfies the defrosting start condition enters the defrosting operation and the defrosting operation ends. The defrosting start condition of the air conditioner whose direction has been changed is changed to a direction in which the condition is established faster than usual (“early defrosting” mode).

When the defrosting start condition of the air conditioner whose delay direction has been changed by the second controller C2 is satisfied and the air conditioner enters the defrosting operation, the fourth controller C4 performs the defrosting operation. The start-up capability for resuming heating of the air conditioner after the completion of is reduced.

[Control of base unit]
The control executed by the indoor controller 24a of the parent device with respect to the communication with the child device will be described with reference to the flowchart of FIG. Steps S1, S2... In the flowchart are simply referred to as S1, S2.

When the start operation of the heating operation is performed by the remote controller 33 (YES in S1), the indoor controller 24a instructs the indoor controllers 24b to 24n to start the heating operation (S2), and the target room set by the remote controller 33. A temperature (also called a set temperature) Ts is instructed to the indoor controllers 24b to 24n (S3). After the heating operation is started, the indoor controller 24a monitors the "in-defrosting" notification (notifying that the defrosting start condition is satisfied) of the indoor controller 24a and the indoor controllers 24b to 24n (S4). When there is no "defrosting" notification (NO in S4), the indoor controller 24a monitors the "defrost end" notification (notification that the defrosting operation has ended) of the indoor controller 24a and the indoor controllers 24b to 24n. Yes (S6). When there is no "defrosting completed" notification (NO in S6), the indoor controller 24a monitors the stop operation of the remote controller 33 (S8).

If there is no stop operation (NO in S8), the indoor controller 24a returns to S3 and repeats the same processing as above. When the stop operation is performed (YES in S8), the indoor controller 24a instructs the indoor controllers 24b to 24n to stop the heating operation (S9).

In the determination of S4, when there is a "defrosting" notification from any of the indoor controllers 24a and the indoor controllers 24b to 24n (YES in S4), the indoor controller 24a determines that all the indoor controllers 24b to 22 "Defrosting" is notified to 24n (S5), and the process proceeds to the determination of S8.

In the determination of S6, if there is a "defrosting end" notification from any of the indoor controllers 24a and the indoor controllers 24b to 24n (YES in S6), the indoor controller 24a determines that all the indoor controllers 24b to 22 24n is notified of "end of defrosting" (S7), and the process proceeds to the determination of S8.

[Control of master unit and slave unit]
The control executed by each of the parent device and the child device will be described with reference to the flowchart of FIG. An example of the defrosting operation executed in the air conditioners 1a to 1c and an example of how the defrosting start condition of the air conditioner 1a changes with the execution of the defrosting operation of these air conditioners 1a to 1c It is shown in FIG.

When there is an instruction to start the heating operation (YES in S11), the indoor controller 24a and the indoor controllers 24b to 24n start the heating operation of the respective air conditioners (S12), and the target room set by the remote controller 33. Each heating capacity (operating frequency F of each compressor 11) is controlled according to the difference ΔT between the temperature Ts and the room temperature Ta detected by the room temperature sensor 23 (S13). After a lapse of a fixed time t1 (for example, 15 minutes) from the start of the heating operation (YES in S14), the indoor controllers 24a to 24n determine a predetermined value, for example, from the current heat exchanger temperature Te of each outdoor heat exchanger 13. The value obtained by subtracting 2° C. is updated and stored in the internal memory as the reference value Teo (=Te-2° C.) of each defrosting start condition (S15). Then, the indoor controllers 24a to 24n monitor the "defrosting" notification (S16).

For example, when the defrosting start condition is satisfied in the indoor controller 24b of the child device, the indoor controller 24b notifies the indoor controller 24a of the parent device that "defrosting". The indoor controller 24a of the parent device that has received the "defrosting" notification notifies all of the indoor controllers 24b to 24n of the child devices that the defrosting is in progress (YES in S4, S5).

The control performed by the indoor controller 24a will be described below as a representative of the indoor controllers 24a to 24n that have received the "defrosting" notification.

When there is no “defrosting” notification (NO in S16) and when there is no defrosting completion notification (NO in S18), the indoor controller 24a determines the “delayed defrosting” mode setting processing in S17 and the “defrosting” in S19. Bypassing without executing the "early defrosting" mode setting process, the process proceeds to the determination of S20, and the reference value Teo (=Te-2°C) stored in S15 and the heat exchanger temperature of the outdoor heat exchanger 13 at the present time It is monitored whether or not the difference ΔTe (=Teo-Te) from Te is equal to or more than the threshold value A (S20). The "delayed defrosting" mode setting process of S17 and the "early defrosting" mode setting process of S19 are performed. If not executed, the setting of the "normal defrost" mode is continued.

When the difference ΔTe is not equal to or more than the threshold value A (NO in S20; when frost formation is small), the indoor controller 24a determines that a certain time, for example, 40 minutes has elapsed from the start of the heating operation, and the heat exchange of the outdoor heat exchanger 13 at the present time. It is monitored whether or not the vessel temperature Te is lower than a predetermined limit value (eg, −20° C.) Tex (S21). When 40 minutes after a fixed time has not elapsed from the start of the heating operation or when the heat exchanger temperature Te of the outdoor heat exchanger 13 at the present time is not less than the limit value Tex (NO in S21), the indoor controller 24a is The process shifts to the determination of the stop instruction in S29.

If the heating operation continues for more than 40 minutes, for example, while the outside air temperature To has dropped to about −20° C., the frost on the outdoor heat exchanger 13 may not be removed even if the defrosting operation is executed. In order to cope with such a low outside air temperature environment, the determination of S21 is adopted as the defrosting start condition.

If the difference ΔTe is equal to or larger than the threshold value A (YES in S20), or if a certain time, for example, 40 minutes has elapsed after the start of the heating operation and the heat exchanger temperature Te is less than the limit value Tex (YES in S21), the indoor controller. 24a starts the defrosting operation of the air conditioner 1a based on the determination that the outdoor heat exchanger 13 needs to be defrosted (S22), and sets "during defrosting" to all the indoor units of the slave unit. Notify the controllers 24b to 24n (S23). With the start of the defrosting operation, the high temperature refrigerant discharged from the compressor 11 is directly supplied to the outdoor heat exchanger 13 through the four-way valve 12, and adheres to the surface of the outdoor heat exchanger 13 by the heat of the high temperature refrigerant. Removed frost.

After the start of the defrosting operation, the indoor controller 24a waits for establishment of a defrosting end condition defined based on the heat exchanger temperature Te of the outdoor heat exchanger 13 (S24).

When the defrosting end condition is satisfied (YES in S24), the indoor controller 24a terminates the defrosting operation of the air conditioner 1a and notifies all the indoor controllers 24b to 24n of the slave units of "end of defrosting". (S25). Then, since the indoor controller 24a continues to set the "normal defrosting" mode in which the reference value Teo and the limit value Tex are not changed at this time (YES in S26), the shift canceling process in the next S27 is performed. Bypass without restarting and restart heating operation (S28). When restarting the heating operation, the indoor controller 24a bypasses the heating without performing the capacity reduction process of S30 because the "normal defrosting" mode setting continues at this point (YES in S29). The operation stop instruction is monitored (S31). If there is no stop instruction (NO in S31), the process returns to S16 and the same process as above is repeated.

In the determination of S16, if there is a "defrosting" notification (YES in S16), the indoor controller 24a newly adds a value obtained by subtracting a predetermined value, for example, 1°C, from the initial reference value Teo updated and stored in S15. The reference value Teo (=initial Teo-1° C.) is stored in the internal memory, and a value obtained by subtracting a predetermined value, for example, 1° C. from the limit value Tex for the heat exchanger temperature Te of the outdoor heat exchanger 13 is newly set as the new limit value Tex. (=initial Tex-1° C.) is stored in the internal memory (S17). That is, the defrosting start condition is changed to be delayed from the normal condition. This change sets the "late defrost" mode.

Subsequently, the indoor controller 24a determines that the difference ΔTe (=new Teo-Te) between the stored new reference value Teo (=initial Teo-1° C.) and the current heat exchanger temperature Te of the outdoor heat exchanger 13 is a threshold value. It is monitored whether it is A or more (S20). When the difference ΔTe is not equal to or larger than the threshold value A (NO in S20), the indoor controller 24a determines that the heat exchanger temperature Te of the outdoor heat exchanger 13 is 40 minutes after a certain time has elapsed from the start of the heating operation and the current heat exchanger temperature Te is above S17. It is monitored whether it is less than the new limit value Tex (=initial Tex-1° C.) stored in step S21.

When the difference ΔTe is equal to or larger than the threshold value A (YES in S20), or when 40 minutes after a fixed time has elapsed from the start of the heating operation and the heat exchanger temperature Te is less than the limit value Tex (YES in S21), that is, the removal is performed. When the frost start condition is satisfied, the indoor controller 24a regardless of whether or not the defrosting operation of the air conditioner 1b that is in the defrosting operation after the defrosting start condition is satisfied first is still continuing. The defrosting operation of the air conditioner 1a is started (S22), and "in-defrosting" is notified to the indoor controllers 24b to 24n of the slave units (S23). After the start of the defrosting operation, the indoor controller 24a waits for the satisfaction of the defrosting end condition (S24).

When the defrosting end condition is satisfied (YES in S24), the indoor controller 24a terminates the defrosting operation of the air conditioner 1a and notifies all the indoor controllers 24b to 24n of the slave units of "end of defrosting". (S25). Then, since the reference value Teo and the limit value Tex are changed and the "delayed defrosting" mode is set at this time (NO in S26), the indoor controller 24a determines that the reference value Teo and the limit value Tex The change is canceled and the normal defrosting mode is returned (S27), and the heating operation is restarted (S28).

When restarting the heating operation, the indoor controller 24a sets the operating frequency F of the compressor 11 to the normal frequency over a predetermined time because the defrosting operation up to now is the "delayed defrosting" mode (NO in S29). It is suppressed to about 80% to reduce the start-up ability for restarting heating (S30).

Subsequently, the indoor controller 24a monitors the heating operation stop instruction (S31). When there is no stop instruction (NO in S31), the indoor controller 24a proceeds to the determination in S16. When there is a stop instruction (YES in S31), the indoor controller 24a stops the heating operation (S32).

As described above, when the defrosting start condition is satisfied in the air conditioner 1b and the air conditioner 1b enters the defrosting operation, all the remaining

air conditioners

1a and 1c except the air conditioner 1b Even if the air conditioner 1b starts the defrosting operation by changing the defrosting start condition of 1n to a direction in which the establishment is delayed (-1° C.) and setting the “delayed defrosting” mode. At the same time, the

other air conditioners

1a and 1c to 1n do not start the defrosting operation. Therefore, the decrease in the indoor temperature Ta in the air-conditioned area due to defrosting can be suppressed as much as possible, and the occupants will not feel discomfort.

Since the indoor controller of the air conditioner that has received the "defrosting" notification simply shifts the reference value Teo and the limit value Tex of the defrosting start condition in each indoor controller, the control of the indoor controllers 24a to 24n becomes complicated. There is nothing to do.

The indoor controllers 24b to 24n of the slaves need only notify the indoor controller 24a of the master of the "defrosting" notification, and notify the identification information such as an address indicating which of the air conditioners is the own air conditioner. Is unnecessary. The indoor controller 24a of the parent device only transfers the notification of "during defrosting" from any of the child devices to all the child devices, and the air conditioner in which the defrosting start condition is satisfied. It is not necessary to notify the identification information such as the address indicating which is. Therefore, the communication control between the master unit and the slave unit can be simplified.

Since the defrosting start timing of the air conditioners 1a to 1n is merely shifted by changing the defrosting start condition, the defrosting operation of one of the air conditioners is not prohibited, and therefore the outdoor of each air conditioner is prevented. There is no problem that the heat exchanger 13 is in a so-called overfrost state without removing the frost.

On the other hand, when the air conditioner 1b that has previously entered the defrosting operation due to the satisfaction of the defrosting start condition ends the defrosting operation and the indoor controller 24b issues a "defrosting end" notification (YES in S18). The indoor controller 24a stores a value obtained by adding a predetermined value, for example, 1° C., to the initial reference value Teo updated and stored in S15 as a new reference value Teo (=initial Teo+1° C.) in the internal memory, and also performs outdoor heat exchange. A value obtained by adding a predetermined value, for example, 1° C., to a predetermined limit value Tex for the heat exchanger temperature Te of the heat exchanger 13 is stored in the internal memory as a new limit value Tex (=initial Tex+1° C.) (S19). .. That is, the defrosting start condition is changed so that the defrosting start condition is established earlier than usual. As a result, the "early defrosting" mode is set.

Subsequently, the indoor controller 24a determines whether the difference ΔTe (=new Teo-Te) between the stored new reference value Teo and the current heat exchanger temperature Te of the outdoor heat exchanger 13 is equal to or greater than the threshold value A. Monitor (S20). When the difference ΔTe is not equal to or greater than the threshold value A (NO in S20), the indoor controller 24a determines that the heat exchanger temperature Te of the outdoor heat exchanger 13 is 40 minutes after the start of the heating operation and 40 minutes after the start of the heating operation. It is monitored whether it is less than the new limit value Tex (=initial Tex+1° C.) stored in step S21.

When the air conditioner 1b that has previously entered the defrosting operation after the defrosting start condition has been satisfied and ends the defrosting operation and restarts heating, while the defrosting start condition of the air conditioner 1b is again established, There is a possibility that the defrosting start conditions of the

air conditioners

1a, 1c to 1n for which the "delayed defrosting" mode is set may overlap.

Therefore, when the defrosting operation is finished and the air conditioner 1b that has entered the defrosting operation first finishes the defrosting operation, the

air conditioners

1a and 1c in which the "delayed defrosting" mode is set. The defrosting start conditions of 1 to 1n are changed so as to be established earlier than usual. In this way, by switching the

air conditioners

1a, 1c to 1n from the "delayed defrosting" mode to the "early defrosting" mode, the defrosting start condition of the air conditioner 1b that has restarted heating is reestablished at an early time. The timing of establishment of the defrosting start condition of the

air conditioners

1a, 1c to 1n can be shifted. That is, it is possible to reduce the possibility that defrosting of a plurality of air conditioners will start at the same timing.

In addition, at the timing when any of the

air conditioners

1a and 1c to 1n in the "delayed defrost" mode starts the defrosting operation, the air conditioner 1b that has previously satisfied the defrosting start condition is still in the defrosting operation. There is a possibility that it is being executed, in which case the defrosting operations of multiple air conditioners will be executed simultaneously. When the plurality of air conditioners respectively finish the defrosting operation and restart the heating as they are, the progress of frost formation of the outdoor heat exchanger 13 of each air conditioner becomes the same, and eventually the plurality of air conditioners are defrosted. The start of frost may come around again at the same timing.

Therefore, when one of the

air conditioners

1a, 1c to 1n in the "delayed defrosting" mode enters the defrosting operation and the defrosting operation ends and the heating is restarted, the compressor 11 is operated for a predetermined time. The operating frequency F of is reduced to about 80% of the normal frequency to reduce the rising capacity for restarting heating. As a result, even if a plurality of air conditioners simultaneously perform the defrosting operation, the degree of frost formation of the outdoor heat exchanger 13 of each air conditioner can be made different. That is, it is possible to reduce the possibility that defrosting of a plurality of air conditioners will start at the same timing.

[Modification]
In the above embodiment, the reference value Teo and the limit value Tex of the defrosting start condition are shifted by -1° C. in the "delayed defrosting" mode, and the reference value Teo and the limit value Tex of the defrosting start condition are set in the early defrosting mode. Although shifted by +1°C, the value to be shifted is not limited to -1°C, and can be appropriately selected according to the capacity of the outdoor heat exchanger 13, the capacity of the heat pump type refrigeration cycle, and the like.

In the above embodiment, the first defrosting start condition that the difference ΔTe (=Teo−Te) between the heat exchanger temperature Te and the reference value Teo is equal to or larger than the threshold value A is used, but the outside air temperature To detected by the outside air temperature sensor 16 is used. May be added to the first defrosting start condition.

In addition, the above embodiments and modifications are presented as examples, and are not intended to limit the scope of the invention. The novel embodiment and the modified examples can be implemented in various other forms, and various omissions, rewritings, and changes can be made without departing from the gist of the invention. These embodiments and modifications are included in the scope of the invention, and are also included in the invention described in the claims and an equivalent range thereof.

1a, 1b, ... 1n ... air conditioner, 10 ... outdoor unit, 11 ... compressor, 13 ... outdoor heat exchanger, 18a, 18b, ... 18n ... outdoor controller, 20 ... indoor unit, 24a, 24b, ... 24n...indoor controller, 33...remote controller, 40...bus line

Claims

A heat pump type refrigeration cycle including a compressor, a four-way valve, an outdoor heat exchanger, a decompressor, and an indoor heat exchanger is provided, and when the defrosting start condition of the outdoor heat exchanger is satisfied, the outdoor heat exchanger is defrosted. A plurality of air conditioners that perform operation,
When starting defrosting of any of the air conditioners, a controller that changes the defrosting start conditions of the remaining air conditioners except the air conditioner that starts defrosting,
An air conditioner comprising:
When the defrosting start condition of one of the air conditioners of the respective air conditioners is satisfied, the controller is a defrosting start condition of the remaining air conditioners other than the air conditioner for which the defrosting start condition is satisfied. Is changed to a direction where establishment is delayed than usual,
The air conditioner according to claim 1, wherein:
The controller is an air conditioner in which the delay direction is changed when the air conditioner in which the defrosting start condition is satisfied enters the defrosting operation after the change in the delay direction and the defrosting operation ends. Change the defrosting start condition of to a direction that will be established sooner than normal,
The air conditioner according to claim 2, wherein
When the defrosting start condition of the air conditioner whose delay direction has been changed is satisfied and the air conditioner enters the defrosting operation, the controller is the same air conditioner after the defrosting operation is completed. Reduce the start-up ability to restart heating
The air conditioner according to claim 2 or 3, characterized in that.