WO2019003306A1

WO2019003306A1 - Air conditioning device

Info

Publication number: WO2019003306A1
Application number: PCT/JP2017/023591
Authority: WO
Inventors: 勇希望月
Original assignee: 三菱電機株式会社
Priority date: 2017-06-27
Filing date: 2017-06-27
Publication date: 2019-01-03
Also published as: JPWO2019003306A1; JP6827540B2

Abstract

This air conditioning device comprises: a refrigeration cycle device in which a compressor for compressing a refrigerant, a condenser for condensing the refrigerant by heat exchange, a throttle device for performing decompression of the refrigerant involved in the condensation, and an evaporator for evaporating the refrigerant involved in the decompression by heat exchange with air are connected by piping to constitute a refrigeration circuit for circulating the refrigerant; a heating device for adjusting and heating the air that has passed through the evaporator, on the basis of the temperature of the air; and a control device for performing control related to the refrigeration cycle device. In an oil return operation in which refrigerant oil in the refrigerant circuit is returned to the compressor, if the control device determines that a frequency obtained by adding a predetermined first set frequency to a drive frequency at which the compressor is currently driven is lower than an accumulation prevention frequency at which the refrigerant oil is prevented from accumulating in the refrigerant circuit, the control device drives the compressor for a first operation period at the frequency obtained by adding the first set frequency to the drive frequency at which the compressor is currently driven, and repeats the determination to raise the drive frequency up to the accumulation prevention frequency, thus performing a control operation.

Description

Air conditioner

The present invention relates to an air conditioner. In particular, it relates to processing and control in oil return operation.

Conventionally, in an air conditioner provided with a refrigerant circuit, a compressor with a variable operating capacity such as an inverter is used to cope with fluctuations in the air conditioning load, and a driving frequency is output to the compressor according to the size of the air conditioning load. Is controlled. By the way, at the time of low load operation where the drive frequency of the compressor is set low, the amount of refrigerant circulating in the refrigerant circuit decreases, so refrigeration oil discharged from the compressor accompanying the refrigerant tends to be retained in the refrigerant circuit. Become. As a result, the amount of refrigerating machine oil in the compressor decreases, and the compressor may overheat, causing seizure and the like.

Therefore, when the low-capacity operation of the compressor continues for a long time, the compressor is forcibly operated at a high capacity, and the oil return operation is performed to increase the refrigerant circulation amount. Then, there is known one in which refrigeration oil accumulated in the refrigerant circuit is returned to the compressor.

Furthermore, while the refrigerant circulation amount is increased, the valve opening degree of the refrigerant flow control valve is increased to sufficiently secure the refrigerant flow amount flowing to the indoor heat exchanger. And what was made to promote recovery of refrigeration oil is known (for example, refer to patent documents 1).

JP 2002-349938 A

In the conventional air conditioner, during the oil return operation, the driving frequency of the compressor is determined independently of the air conditioning load. For this reason, the blowing temperature is reduced.

Here, an electric heater can be installed in the air conditioning apparatus or in a duct connected to the outlet of the air conditioning apparatus, and the air conditioning apparatus can be set to keep the temperature and humidity of the air in the space to be air conditioned constant. (Referred to as a constant temperature and humidity air conditioner). In the constant temperature and humidity air conditioning apparatus, keeping constant the temperature of the air in the space to be air conditioned and keeping the circulating air volume constant is given priority over energy saving.

In a constant temperature and humidity air conditioning apparatus, generally, in a refrigeration cycle apparatus in the air conditioning apparatus, the air is cooled and heated by an electric heater to maintain the temperature of the air in the air conditioned space constant. Is done. Even in the case of a constant temperature and humidity air conditioner, the outside air temperature is low, and the air conditioner can easily exhibit its cooling capacity, or the amount of heat processed by the air conditioner can be small due to intrusion of outside air, heat radiation, etc. In some cases, the operating frequency of the compressor is lowered and oil return operation is performed periodically.

When the oil return operation is performed, the compressor frequency rises regardless of the air conditioning load, so the blow-out temperature decreases and the temperature of the air in the air-conditioned space decreases until the electric heater follows. There was a problem. In particular, in factories, inspection rooms, test rooms and the like where temperature control is severe, there is a demand to avoid that the temperature of the air in the space to be air-conditioned fluctuates, even while performing the oil return operation.

The present invention has been made to solve the problems as described above, and it is an object of the present invention to obtain an air conditioner that can stabilize air sent to a space to be air-conditioned during oil return operation.

The air conditioner according to the present invention relates to pressure reduction by heat exchange with air, a compressor for compressing the refrigerant, a condenser for condensing the refrigerant by heat exchange, a throttling device for reducing the pressure of the refrigerant related to condensation, and air. A refrigeration cycle apparatus constituting a refrigerant circuit that circulates a refrigerant by connecting an evaporator that evaporates the refrigerant with a pipe, and a heating apparatus that adjusts and heats air that has passed through the evaporator based on the temperature of the air And a control device for performing control relating to the refrigeration cycle device, wherein the control device predetermines the drive frequency at which the compressor is currently driven in the oil return operation for returning the refrigeration oil in the refrigerant circuit to the compressor. If it is determined that the frequency to which the first set frequency is added is lower than the retention prevention frequency which prevents the retention of the refrigeration oil in the refrigerant circuit, the drive frequency currently being driven is added with the first setting frequency. The number, the first driving time to drive the compressor, by repeating the determination until retention prevention frequency, performs control to increase the driving frequency.

According to the air conditioner of the present invention, the control device performs control to gradually raise the drive frequency of the compressor to the stagnation prevention frequency. Therefore, in the heating device, from the evaporator of the refrigeration cycle device The heating based on the temperature of the air can be made to follow. For this reason, the temperature of the air sent from the air conditioning apparatus to the air conditioning target space can be stabilized.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the outline | summary of a structure of the air conditioning apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the structure of the outdoor unit controller 115 which concerns on Embodiment 1 of this invention. It is a figure explaining the process sequence which concerns on the oil return operation of the air conditioning apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the process sequence which concerns on oil return operation of the air conditioning apparatus which concerns on Embodiment 2 of this invention. It is a figure explaining the process sequence which concerns on oil return operation of the air conditioning apparatus which concerns on Embodiment 3 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, in the following drawings, what attached the same code is the same or it corresponds to this, and suppose that it is common in the whole text of the embodiment described below. Further, the form of the constituent elements shown in the entire specification is merely an example, and the present invention is not limited to these descriptions. In particular, the combination of components is not limited to only the combination in each embodiment, and the components described in the other embodiments can be applied as appropriate to other embodiments. The height and the height of the temperature and the pressure are not particularly determined in relation to the absolute value, but are relatively determined in the state and operation of the device or the like.

Embodiment 1
FIG. 1 is a diagram showing an outline of a configuration of an air conditioner according to Embodiment 1 of the present invention. The air conditioning apparatus according to the first embodiment is a constant temperature and humidity air conditioning apparatus. The air conditioning apparatus of Embodiment 1 includes a refrigeration cycle apparatus 100 and a heating apparatus 200. In the first embodiment, the refrigeration cycle apparatus 100 cools air. The heating device 200 also heats the air from the refrigeration cycle apparatus 100. The air conditioning apparatus sends air whose temperature and humidity have been adjusted by the refrigeration cycle apparatus 100 and the heating apparatus 200 to the air conditioning target space. Here, the space to be air conditioned in the following description is, for example, a space corresponding to a room, a laboratory, an operating room, a manufacturing site, an examination room, a room of a building, a warehouse, and the like.

<Description of configuration>
As shown in FIG. 1, the refrigeration cycle apparatus 100 according to Embodiment 1 has an outdoor unit 110 and an indoor unit 120. The outdoor unit 110 and the indoor unit 120 are connected by the indoor / outdoor communication liquid piping 130 and the indoor / outdoor communication gas piping 140.

The outdoor unit 110 includes a compressor 111, an oil separator 112, an outdoor fan 114, an outdoor heat exchanger 113, and an outdoor unit controller 115. The compressor 111 compresses and discharges the sucked refrigerant. Here, the compressor 111 may be provided with an inverter device or the like to finely change the capacity of the compressor 111 (the amount of refrigerant to be sent per unit time) by arbitrarily changing the number of rotations based on the driving frequency F. it can. The oil separator 112 separates refrigeration oil discharged together with a gaseous refrigerant (gas refrigerant) discharged from the compressor 111 from the gas refrigerant. The refrigeration oil separated in the oil separator 112 is returned to the compressor 111 through a capillary (not shown) connected to the compressor 111. The oil separator 112 can return most of the refrigerator oil discharged from the compressor 111 to the compressor 111.

The outdoor heat exchanger 113 is a heat exchanger to be a condenser. The outdoor heat exchanger 113 performs heat exchange between the refrigerant discharged from the compressor 111 and the air outside the room to condense and liquefy the refrigerant. The outdoor fan 114 is installed corresponding to the outdoor heat exchanger 113. The outdoor fan 114 allows outdoor air to pass through the outdoor heat exchanger 113 in order to efficiently exchange heat between the refrigerant and the outdoor air. For the outdoor fan 114, for example, the driving frequency of the fan motor may be arbitrarily changed by an inverter device to finely change the rotational speed of a propeller or the like. The outdoor unit controller 115 performs control of the apparatus which the outdoor unit 110 has. Here, in particular, control regarding the compressor 111 is performed. The configuration of the outdoor unit controller 115 will be described later.

The indoor unit 120 includes an indoor fan 123, an indoor heat exchanger 122, an expansion valve 121, an indoor unit controller 124, and a suction temperature sensor 125. The expansion valve 121 serving as the expansion device is a valve that decompresses and expands the refrigerant. As a device for reducing the pressure of the refrigerant other than the expansion valve 121, there is, for example, a capillary (capillary tube) or the like. The indoor heat exchanger 122 is a heat exchanger to be an evaporator. The indoor heat exchanger 122 exchanges heat between the refrigerant that has passed through the expansion valve 121 and the air outside the room to evaporate and evaporate the refrigerant. The indoor fan 123 is installed corresponding to the indoor heat exchanger 122. The indoor fan 123 passes the air to the indoor heat exchanger 122 in order to efficiently exchange heat between the air and the refrigerant. For the indoor fan 123, for example, the driving frequency of the fan motor may be arbitrarily changed by an inverter device to finely change the rotational speed of a propeller or the like. The indoor unit controller 124 controls devices included in the indoor unit 120. The suction temperature sensor 125 flows into the indoor unit 120, detects the temperature of the air sent to the indoor heat exchanger 122, and sends a signal related to the detection to the indoor unit controller 124.

The heating device 200 also includes an electric heater 201 and an electric heater controller 202. The electric heater 201 heats the air that has passed through the indoor heat exchanger 122. Here, in the first embodiment, the electric heater 201 is installed in the indoor unit 120 of the refrigeration cycle apparatus 100. The electric heater 201 is controlled by the electric heater controller 202. The electric heater controller 202 controls the heating of the air by the electric heater 201 so that the air in the air conditioning target space has the set temperature and the set humidity. Here, the electric heater 201 may be installed inside a duct attached to the outlet of the indoor unit 120. Further, the electric heater controller 202 may be installed inside the indoor unit 120. Also, it may be integrated with the indoor unit controller 124.

<Operation of air conditioner>
Next, the operation of the air conditioner according to Embodiment 1 will be described. Here, the flow of refrigeration oil during cooling operation in the refrigerant circuit of the air conditioning apparatus of Embodiment 1 will be described. The compressor 111 compresses and discharges the refrigerant. At this time, refrigeration oil is also discharged together with the refrigerant. The refrigeration oil discharged together with the refrigerant from the compressor 111 is mostly recovered by the oil separator 112 provided in the vicinity of the pipe on the discharge side of the compressor 111. The refrigeration oil recovered by the oil separator 112 is returned to the compressor 111 along a path different from the main refrigerant circuit.

The refrigeration oil not recovered by the oil separator 112 flows through the indoor / outdoor communication liquid pipe 130 and flows into the indoor unit 120. Here, when the drive frequency F of the compressor 111 is high and the circulation amount of the refrigerant circulating in the refrigerant circuit is large, the refrigeration oil passes through the indoor unit 120 and flows through the indoor / outdoor communication gas pipe 140 and the compressor 111 I will return without trouble. On the other hand, when the drive frequency F of the compressor 111 is low and the circulation amount of the refrigerant in the refrigerant circuit is small, the transport force for the refrigerator oil is reduced. For this reason, refrigeration oil tends to stay in the indoor / outdoor communication gas pipe 140 and the indoor heat exchanger 122.

FIG. 2 is a diagram for explaining the configuration of the outdoor unit controller 115 according to Embodiment 1 of the present invention. As shown in FIG. 2, the outdoor unit controller 115 according to the first embodiment includes a control device 300, a storage device 310, and a timing device 320. The control device 300 includes a comparison / determination unit 301, an operation unit 302, and a control unit 303. In the first embodiment, comparison determination section 301 performs comparison based on a plurality of data, and performs determination. In addition, the calculation unit 302 performs calculation processing. In the first embodiment, in particular, the calculation regarding the drive frequency F of the compressor 111 is performed. The control unit 303 controls devices included in the outdoor unit 110. In particular, a process related to the oil return operation is performed, and control regarding the drive frequency F of the compressor 111 is performed.

The storage device 310 is a device that stores data related to the processing of the control device 300. Here, recording regarding the drive frequency F of the compressor 111 is performed. Further, the clocking device 320 has a timer or the like to clock an elapsed time or the like.

Here, in the first embodiment, it is assumed that control device 300 of outdoor unit controller 115 is formed of, for example, a microcomputer having a CPU (Central Processing Unit) and the like. Further, the storage device 310 stores data in which a processing procedure related to control and the like is a program. Then, based on the data of the program stored in the storage device 310, the control device 300 executes the processing of each part to realize control. However, the present invention is not limited to such a configuration, and each unit of the control device 300 may be configured by different dedicated devices (hardware) to realize each function.

FIG. 3 is a view for explaining the processing procedure according to the oil return operation of the air conditioning apparatus according to Embodiment 1 of the present invention. Next, processing and control relating to the oil return operation will be described. Here, the outdoor unit controller 115 will be described as performing the processing and control related to the oil return operation as the entire device.

When performing the normal operation which is an operation of air conditioning the space to be air-conditioned, for example, periodically, the outdoor unit controller 115 determines whether the condition of the oil return operation is satisfied as shown in step S101. Do. If it is determined that the condition is not satisfied, the process proceeds to step S108, continues normal operation, and ends the process.

Here, in step S101, it is determined whether or not the oil return operation is necessary, but the determination condition is not particularly limited. Generally, whether or not the operation at the driving frequency F of the compressor 111 is continued for a predetermined time or more such that the flow velocity of the refrigerant in the indoor / outdoor communication gas pipe 140 becomes a predetermined speed or less. can do. Here, based on the temperature of the refrigerant sucked into the compressor 111, the low pressure side pressure, and the like, the frequency serving as the determination threshold and the operating time may be corrected.

If it is determined in step S101 that the condition is satisfied, the oil return operation is started. When the oil return operation is started, in step S102, the outdoor unit controller 115 records the start frequency Fstart, which is the drive frequency F at the start of the oil return operation, and proceeds to step S103. In step S103, it is determined whether the constant temperature and humidity setting is made. If it is determined that the constant temperature and humidity setting is made, the process proceeds to step S104. If it is determined that the constant temperature and humidity setting is not made, the process proceeds to step S108.

In step S104, the current drive frequency Fnow which is the drive frequency F currently driven by the compressor 111 is recorded, and the process proceeds to step S105. In step S105, the frequency of the sum of the current drive frequency Fnow and the maximum frequency change amount ΔFmax is compared with the retention prevention frequency Fr. Here, the maximum frequency change amount ΔFmax is a first set frequency which is set in advance in consideration of the influence on the blowout temperature, and is set to the maximum frequency which can be raised at one time. The first set frequency is, for example, a frequency such that the variation of the outlet temperature is less than 0.5 ° C., and a frequency of approximately 1 to 5 Hz is set. The first set frequency can be any frequency as long as it does not exceed the maximum frequency change amount ΔFmax. The retention prevention frequency Fr is a frequency necessary for driving the compressor 111 for preventing retention of the refrigeration oil in the refrigerant circuit in the oil return operation. The stagnation prevention frequency Fr is determined, for example, such that the flow velocity of the refrigerant in the indoor / outdoor communication gas pipe 140 is equal to or higher than a certain speed, and a frequency of about several tens Hz is set.

If it is determined that the sum of the current drive frequency Fnow and the maximum frequency change amount ΔFmax is smaller than the retention prevention frequency Fr, the process proceeds to step S106. If it is determined that the sum of the current drive frequency Fnow and the maximum frequency change amount ΔFmax is equal to or higher than the retention prevention frequency Fr, the process proceeds to step S108.

In step S106, an instruction to drive the drive frequency F of the compressor 111 as the frequency of the sum of the current drive frequency Fnow and the maximum frequency change amount ΔFmax is issued, and the process proceeds to step S107. In step S107, the operation is continued for the first operation time t1, and the process proceeds to step S104. Then, the comparison process with the retention prevention frequency Fr is repeated until the drive frequency F of the compressor 111 becomes the retention prevention frequency Fr.

Here, the first operation time t1 is a time set as a time until the output of the electric heater 201 rises and the blowout temperature returns to the set temperature. The first operation time t1 may be set based on the control logic of the electric heater 201, the allowable temperature fluctuation of the air conditioning target space, and the like, in association with the maximum frequency change amount ΔFmax. In addition, a user, an operator, or the like may set the outdoor unit controller 115.

On the other hand, when it is determined in step S103 that the constant temperature and humidity setting is not made, or when it is determined in step S105 that the sum of the current drive frequency Fnow and the maximum frequency change amount ΔFmax is not less than the retention prevention frequency Fr , And proceeds to step S108. In step S108, the compressor 111 is instructed to drive the drive frequency F at Fr, and the process proceeds to step S109.

In step S109, the operation related to the oil return is continued for the second operation time t2, and the process proceeds to S110. In step S110, the process shifts to normal operation. Here, the second operation time t2 is a time set in consideration of the time until the refrigeration oil returns to the outdoor unit 110. The second operation time t2 may be set based on the length and diameter of the heat transfer pipe of the indoor heat exchanger 122, the length and diameter of the indoor / outdoor communication gas pipe 140, and the like.

As described above, according to the air conditioning apparatus according to the first embodiment, the drive frequency F of the compressor 111 is gradually increased while preventing the discharge temperature from being suddenly lowered in the oil return operation. Therefore, the heating by the electric heater 201 can be made to follow. Therefore, particularly in the case of constant temperature and constant humidity setting, the temperature of the air sent from the air conditioner to the space to be air conditioned can be kept substantially constant. Therefore, the temperature of air in the air conditioning target space is stabilized, and stable operation of the manufacturing apparatus in the air conditioning target space, quality improvement of the product, and the like can be achieved.

Second Embodiment
In Embodiment 1, the processing and control in the oil return operation of the air conditioner have been described. Here, the driving frequency F of the compressor 111 after the oil return operation is performed is higher than the air conditioning load of the space to be air conditioned, and is not balanced with the air conditioning load. Therefore, the output of the electric heater 201 is also larger than necessary. In order to save energy, when the oil return operation is finished, the drive frequency F of the compressor 111 may be returned to a frequency that balances with the air conditioning load of the space to be air conditioned. However, if the drive frequency F of the compressor 111 is largely changed, the temperature fluctuation becomes large. Therefore, in the air-conditioning apparatus of Embodiment 2, when shifting to the normal operation, the drive frequency F of the compressor 111 is lowered by the maximum frequency change amount ΔFmax which is the second set frequency. Here, the second set frequency can be any frequency as long as it does not exceed the maximum frequency change amount ΔFmax.

FIG. 4 is a view for explaining the processing procedure according to the oil return operation of the air conditioning apparatus according to Embodiment 2 of the present invention. Next, the operation of the air conditioning apparatus according to Embodiment 2 will be described. Here, also in the second embodiment, the outdoor unit controller 115 will be described as performing control related to the oil return operation. In FIG. 4, the same step numbers are assigned to the same operations as described in the first embodiment.

In the second embodiment, as shown in FIG. 4, after continuing the second operation time t2 operation in step S109, in step S109A, a drive frequency F reduced by the maximum frequency change amount ΔFmax from the retention prevention frequency Fr. Command the compressor 111 to drive the Then, in step S109B, the drive frequency F is compared with the start frequency Fstart. If it is determined that the drive frequency F and the start frequency Fstart coincide with each other, the process proceeds to step S110. If it is determined that the drive frequency F and the start frequency Fstart do not match, the process proceeds to step S109C. In step S109C, it is determined whether the difference between the drive frequency F and the start frequency Fstart is larger than the maximum frequency change amount ΔFmax. When it is determined that the difference between the drive frequency F and the start frequency Fstart is equal to or less than the maximum frequency change amount ΔFmax, the drive frequency F is set as the start frequency Fstart in step S109D, and the process proceeds to step S110. When it is determined that the difference between the drive frequency F and the start frequency Fstart is larger than the maximum frequency change amount ΔFmax, the drive frequency F is reduced by the maximum frequency change amount ΔFmax to be a new drive frequency F in step S109E. Then, the determination in step S109B is performed again. In step S110, the compressor 111 shifts to normal operation at a drive frequency F based on the instruction.

As described above, according to the air conditioning apparatus of Embodiment 2, the outdoor unit controller 115 reduces the maximum frequency change amount ΔFmax from the retention prevention frequency Fr in the normal operation after the oil return operation. An instruction to drive the compressor 111 is given at the driving frequency F. For this reason, it is possible to perform the cooling of the air by the refrigerant circuit in accordance with the air conditioning load in the space to be air conditioned and the heating of the air by the electric heater 201. Therefore, energy saving can be achieved. In addition, since the drive frequency F is reduced by the maximum frequency change amount ΔFmax rather than the stay prevention frequency Fr without reducing the drive frequency F at once, sudden changes in temperature can be suppressed. The temperature of the air to be sent can be kept constant.

Third Embodiment
FIG. 5 is a view for explaining the processing procedure according to the oil return operation of the air conditioning apparatus according to Embodiment 3 of the present invention. Next, the operation of the air conditioning apparatus according to Embodiment 3 will be described. Here, also in the third embodiment, the outdoor unit controller 115 will be described as performing control related to the oil return operation. In FIG. 5, the same step numbers are assigned to the same operations as described in the first embodiment.

In the third embodiment, after the condition for performing the oil return operation is satisfied, an operation transition period t3 is provided until the oil return operation is performed. At this time, at the time of the prior signal output time t4 which is shorter than the operation transition period t3, the electrical heater controller 202 is made to output the prior signal which is a prior signal for notifying in advance the oil return operation. By sending the advance signal, the delay of the tracking of the electric heater 201 is prevented.

When it is determined in step S101 that the condition for performing the oil return operation is satisfied, it is further determined in step S101A whether or not the prior signal output time t4 has elapsed. If it is determined in step S101A that the prior signal output time t4 has elapsed, a prior signal is output to the electric heater controller 202 in step S101B so that the output of the electric heater 201 is adjusted before the oil return operation is started. Make it

Then, in step S101C, it is further determined whether the set time A has elapsed. If it is determined that the set time A has elapsed, the process proceeds to step S102. Here, the setting time A is a time obtained by subtracting the prior signal output time t4 from the driving transition period t3. In step S102, the oil return operation is started, and the start frequency Fstart is recorded.

As described above, according to the air conditioning apparatus of the third embodiment, when it is determined that the oil return operation is to be performed, the prior signal output time t4 within the operation transition period t3 is a prior signal to the electric heater controller 202 Since it sends, it is possible to adjust the output of the electric heater 201 before performing the oil return operation. Therefore, the temperature of the air blown from the indoor unit 120 to the space to be air conditioned can be kept substantially constant. Therefore, the temperature of the air conditioning target space is stabilized, and stable operation of the manufacturing apparatus and improvement of product quality can be achieved.

Here, it is known in advance that the end of the oil return operation ends when the second operation time t2 has elapsed since the compressor 111 was driven at the retention prevention frequency Fr. For this reason, the electric heater controller 202 can control the electric heater 201 even without the advance signal. However, the advance signal may be sent to the electric heater controller 202 as well as when the oil return operation is started.

Fourth Embodiment
In the first to third embodiments described above, the outdoor unit controller 115 includes the control device 300 and the like and performs the processing related to the oil return operation, but the present invention is not limited to this. For example, the indoor unit controller 124 may perform control or the like. Also, an external control device may perform it.

Moreover, in embodiment mentioned above, although the process and control in the air conditioning apparatus for constant temperature and humidity were demonstrated, it does not limit to this. For example, in the case where one target space is cooled or heated by a plurality of air conditioners, etc., when one air conditioner performs an oil return operation, the other air conditioner performs capacity control of the compressor. Thus, the temperature of the target space can be kept constant. For this reason, it can apply also in a normal refrigerating cycle device.

Reference Signs List 100 refrigeration cycle apparatus, 110 outdoor unit, 111 compressor, 112 oil separator, 113 outdoor heat exchanger, 114 outdoor fan, 115 outdoor unit controller, 120 indoor unit, 121 expansion valve, 122 indoor heat exchanger , 123 indoor fan, 124 indoor unit controller, 125 suction temperature sensor, 130 indoor / outdoor communication liquid piping, 140 indoor / outdoor communication gas piping, 200 heating device, 201 electric heater, 202 electric heater controller, 300 control device, 301 Comparison determination unit, 302 operation unit, 303 control unit, 310 storage device, 320 clock device.

Claims

Evaporation to evaporate the refrigerant related to the decompression by heat exchange with a compressor that compresses the refrigerant, a condenser that condenses the refrigerant by heat exchange, an expansion device that decompresses the refrigerant related to condensation, and heat exchange with air A refrigeration cycle apparatus constituting a refrigerant circuit which is connected by a pipe to circulate the refrigerant.
A heater for adjusting and heating the air that has passed through the evaporator based on the temperature of the air;
A control device for performing control related to the refrigeration cycle device;
The controller is
In an oil return operation for returning refrigeration oil in the refrigerant circuit to the compressor, a frequency obtained by adding a first predetermined frequency determined in advance to a drive frequency at which the compressor is currently driven corresponds to the refrigeration oil of the refrigeration oil If it is determined that the frequency is lower than the retention prevention frequency for preventing retention in the refrigerant circuit, the compressor is driven for a first operation time at a frequency obtained by adding the first set frequency to the drive frequency currently being driven; An air conditioner that performs the control to increase the drive frequency up to the stagnation prevention frequency by repeating the determination.
The air conditioning apparatus according to claim 1, wherein the control device performs the control when a constant temperature and humidity setting is performed to maintain a set temperature and a set humidity in a space to be air-conditioned in normal operation.
The control device drives the compressor at a frequency obtained by subtracting a predetermined second set frequency from the retention prevention frequency when driving the compressor at the retention prevention frequency for a second operation time. The air conditioner according to claim 1 or 2, wherein control is performed to shift to normal operation.
When it is determined that the oil return operation is to be performed, the control device sends a signal to the heating device in advance, and then starts the oil return operation after a predetermined set time has elapsed. An air conditioner according to any one of claims 1 to 3.