JP6509013B2 - Refrigerating apparatus and refrigerator unit - Google Patents

Description

  The present invention relates to a refrigeration apparatus and a refrigerator unit, and more particularly to an apparatus for performing oil return operation control for returning lubricating oil to the compressor side.

  In a refrigeration system in which a compressor, a condenser, a pressure reducing device, and an evaporator are sequentially connected by a refrigerant pipe to configure a refrigeration cycle, when the compressor is operated, lubricating oil in the compressor is combined with the refrigerant in the refrigeration cycle. It flows out to a certain refrigerant circuit side. The lubricating oil circulates in the refrigerant circuit together with the refrigerant and returns to the compressor again, but a part of the lubricating oil stagnates in the refrigerant circuit. If the amount of retained lubricating oil increases, the amount of lubricating oil in the compressor may be insufficient, resulting in poor lubrication.

  In order to solve this problem, conventionally, the operating time of the refrigerant circuit is integrated, and the integrated time is forcibly stopped every time a predetermined time elapses, and then the compressor is operated at full speed for a predetermined time to lubricate the compressor An oil return operation to return the oil is being performed. As this kind, a prior art, there exists a thing as described in Unexamined-Japanese-Patent No. 2003-106690 (patent document 1), for example.

  The reason for forcibly stopping the compressor is that, at the time of restart after the compressor is stopped, all the compressors are operated at high speed and the refrigerant circulation amount is increased, and the refrigerant is used as refrigerant piping or cooler It is expected that the retained oil will be washed away and the compressor will recover the oil.

  In the case of Patent Document 1, the operation state of the refrigerant circuit is detected, and the oil return operation is performed when the operation state in which oil depletion is concerned continues for a predetermined time. For example, a refrigerant circulation amount detector for detecting the circulation amount of the refrigerant or an oil amount detector for detecting the oil amount in the compressor is provided, and the oil return operation is performed when the operation state in which oil depletion is concerned continues for a predetermined time. To carry out.

Japanese Patent Application Publication No. 2003-106690

In the thing of the above-mentioned patent documents 1, it is feared that oil exhaustion is concerned by providing a refrigerant circulation amount detector which detects a circulation amount of a refrigerant, or providing an oil amount detector (oil level sensor) which detects the oil amount in a compressor. With respect to performing the oil return operation when the operating condition continues for a predetermined time, it is described. However, although the thing of this patent document 1 is described regarding performing oil return operation, sufficient consideration is not made about reliably returning oil to a compressor.
Moreover, in the thing of patent document 1, in order to detect the driving | running state of a refrigerant circuit, it is necessary to provide special detectors, such as an oil quantity detector.

  Furthermore, in the case of Patent Document 1 described above, no consideration is given to the decrease in the amount of oil returned to the compressor when the operation of the compressor is continued at a low frequency or at the time of trial operation of the refrigeration system.

  An object of the present invention is to provide a refrigeration unit and a refrigeration unit capable of reliably returning oil to the compressor even when the compressor is continuously operated at a low frequency or at the trial operation of the refrigeration unit.

In order to achieve the above object, the present invention provides a compressor capable of capacity control, a condenser for condensing high pressure refrigerant compressed by the compressor, and a decompression device for decompressing high pressure refrigerant condensed by the condenser. A refrigeration apparatus comprising a refrigeration cycle connected in sequence by a refrigerant pipe to an evaporator for evaporating refrigerant refrigerant decompressed by the decompression device, the controller comprising a controller for controlling the operating capacity of the compressor, the controller comprising: A function of determining the low capacity operation requiring oil return operation to the compressor and integrating the operating time at the low capacity; and a function of integrating the number of start / stop times of the compressor The oil return when the integrated operation time at the low capacity of the compressor has exceeded a preset integration operating time, or when the number of start / stop times of the compressor exceeds a preset start / stop number Operation control Comprising starts selling feature, the oil-return operation control is characterized by an oil return operation control in the test operation mode which is performed during the predetermined predetermined time the start of the operation of the refrigeration system (set commissioning time).

  Another feature of the present invention is a compressor capable of capacity control, a condenser for condensing high pressure refrigerant compressed by the compressor, and a decompression device for decompressing high pressure refrigerant condensed by the condenser. In a refrigeration system configured by sequentially connecting refrigerant pipes with an evaporator that evaporates a refrigerant that has been depressurized by a pressure reducing device, the controller includes a controller that controls an operating capacity of the compressor, and the controller It is determined that the operation is performed at a low capacity (low operation frequency) where oil return operation is required, and the function of integrating the operation time at this low capacity, and the integrated operation time at the low capacity of the compressor A function to perform oil return operation control for starting forced operation after forcibly stopping the compressor when a preset integration operation time has elapsed, and a suction side of the compressor during the oil return operation control The pressure is predetermined A refrigeration system having a function of performing an oil return retry operation for starting forced operation after forcedly stopping the compressor when the pressure falls below a constant pressure value until a set operation time of the oil return operation control elapses is there.

Yet another feature of the present invention is a controller for controlling the operating capacity of the compressor in a refrigerator unit including a compressor capable of capacity control and a condenser for condensing high pressure refrigerant compressed by the compressor. The controller has a function of determining that the compressor is operated at a low capacity that requires an oil return operation to the compressor and integrating the operating time at the low capacity, and the number of times of start / stop of the compressor When the integrated operation time at the low capacity of the compressor exceeds a preset integrated operating time, or the number of start / stop times of the compressor exceeds the preset start / stop frequency. when, a function of performing oil-return operation control, the oil-return operation control, an oil return operation control in the test operation mode which is performed during the predetermined predetermined time the start of the operation of the refrigeration system (set commissioning time) In the refrigerator unit that.

  Yet another feature of the present invention is a controller for controlling the operating capacity of the compressor in a refrigerator unit including a compressor capable of capacity control and a condenser for condensing high pressure refrigerant compressed by the compressor. The controller is configured to determine that it is operated at a low capacity that requires an oil return operation to the compressor and to integrate the operating time at this low capacity; and the low capacity of the compressor Function of performing oil return operation control for starting forced operation after forcibly stopping the compressor when the integrated operation time at the predetermined integrated operation time has passed, and during the oil return operation control The oil return retry operation for starting the forced operation after forcibly stopping the compressor when the suction side pressure of the compressor becomes equal to or less than a predetermined set pressure value, the set operation time of the oil return operation control Has passed In refrigerator unit having a function of performing up to that.

  According to the present invention, it is possible to obtain a refrigeration unit and a refrigeration unit capable of reliably returning oil to the compressor even when the compressor is continuously operated at a low frequency or at the time of trial operation of the refrigeration unit. is there.

BRIEF DESCRIPTION OF THE DRAWINGS The refrigerating-cycle block diagram which shows Example 1 of the freezing apparatus of this invention. FIG. 7 is a flow chart for explaining the operation of oil return operation control in the refrigeration system shown in FIG. 1. The flowchart explaining operation | movement of general oil return operation control in a freezing apparatus.

  Hereinafter, specific examples of the refrigeration apparatus and the refrigerator unit of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a refrigeration cycle showing Embodiment 1 of the refrigeration system of the present invention.
In FIG. 1, I is a refrigeration system, and this refrigeration system I is constituted by a refrigeration unit II installed outdoors, and a low pressure device III installed indoors and connected to the refrigeration unit II by a refrigerant pipe 20 It is done.

  The low-pressure device III is a showcase installed in a store such as a supermarket and cooling an object such as food. Such a showcase is generally susceptible to large fluctuations in load. The low-pressure device III is not limited to the showcase, but is similarly applicable to other types of refrigerators and freezers, indoor units of air conditioners, and the like, and the number of low-pressure devices is also plural. Parallel connection is also possible.

  The refrigerator unit II sucks and compresses a low-pressure gas refrigerant (low-pressure refrigerant), and discharges a high-temperature high-pressure gas refrigerant (high-pressure refrigerant) (capacity control is possible) Condenser 2, which condenses high-temperature, high-pressure gas refrigerant discharged from compressor 1 into high-temperature, high-pressure liquid refrigerant, receiver 3 for storing liquid refrigerant from this condenser 3, liquid from receiver 3 The air subcooling heat exchanger 4 and the like further subcool the refrigerant. Reference numeral 7 denotes a liquid injection circuit including a pressure reducing device 7a, which branches part of the liquid refrigerant flowing through the main circuit and injects the liquid refrigerant into the intermediate pressure portion of the compressor 1 to cool the compressor 1 It is a thing.

  Further, in the refrigerator unit II, a suction pressure sensor 11 for detecting the pressure on the suction side of the compressor 1, a discharge temperature sensor 12 for detecting the temperature on the discharge side of the compressor 1, and a discharge of the compressor 1 A discharge pressure sensor 13 which heats the pressure on the side and a controller 14 which receives the detection values of these sensors and controls the compressor 1, the pressure reducing device 7a and the like are provided. Reference numeral 30 denotes a cooling fan for ventilating the outside air to the condenser 2 and the air subcooling heat exchanger 4 for cooling.

  The low pressure device III connected to the refrigerator unit II and the refrigerant pipe 20 includes a pressure reducing device 5 for reducing the pressure of the high pressure liquid refrigerant condensed in the condenser 2, and a low temperature and low pressure pressure reduced by the pressure reducing device 5. It is comprised by the evaporator 6 etc. which evaporate a refrigerant | coolant. The pressure reducing device 5 is constituted by an expansion valve or the like.

The low-pressure gas refrigerant evaporated by the evaporator 6 is returned to the compressor 1 of the refrigerator unit II, compressed again, and circulated to constitute the main circuit of the refrigeration cycle.
The controller 14 estimates the load fluctuation of the refrigeration cycle on the basis of the pressure value detected by the suction pressure sensor 11, and controls the capacity of the compressor 1. Further, in the present embodiment, the controller 14 determines that the operation is performed at a low capacity (low operating frequency) where the oil return operation to the compressor 1 is required, and the operation time at this low capacity is determined. And the function of integrating the number of ON / OFF times of the compressor 1. Furthermore, the controller 14 may be configured such that the operating time at the low capacity of the compressor 1 has exceeded a predetermined time (set integration time), or the number of times of start / stop of the compressor 1 (number of stops) is in advance. It has a function to perform oil return operation control when the set number (set start / stop number) is exceeded.

  The value of the low operation frequency (set frequency) for determining that the compressor 1 is operated at a low capacity that requires oil return operation, the set integration time, the set start / stop count, etc. 14 and is configured to be changeable by the controller 14.

Next, the operation of oil return operation control of the refrigeration system in the present embodiment will be described in comparison with general oil return operation control.
First, the operation of general oil return operation control in the refrigeration system will be described with reference to FIG. 1 according to the flowchart shown in FIG.

  Step S101 shown in FIG. 3 shows a state in which the refrigeration system I shown in FIG. 1 is in normal operation, and in this normal operation, the suction side pressure of the compressor 1 detected by the suction pressure sensor 11 is It is input to the controller 14. Then, the frequency (number of revolutions) of the compressor 1 is controlled so that the suction side pressure falls within the allowable range of the preset pressure, and follows the change in the load condition of the low pressure device III shown in FIG. Suction pressure control is performed (step S101). That is, since the temperature change of the low pressure device III can be detected by detecting the suction side pressure of the compressor 1, the temperature of the low pressure device III is controlled by controlling the suction side pressure to be within the allowable range. Can be kept stable.

  More specifically, if the detected suction-side pressure is equal to or higher than the upper limit of the allowable range (the allowable range), the controller 14 causes the compressor 1 to increase the operating frequency. An operating frequency command is issued. On the other hand, if the detected suction-side pressure is equal to or less than the lower limit of the allowable range, the controller 14 issues an operating frequency command to the compressor 1 so as to decrease the operating frequency of the compressor 1.

  During normal operation, the amount of oil in the compressor 1 is monitored, and the operating frequency of the compressor 1 is monitored in order to ensure a predetermined amount at all times. Here, when the operating frequency becomes equal to or lower than the set frequency, the process proceeds to step S102, and the integrated operating time is counted.

  Next, the process proceeds to step S103, and it is determined whether or not the integrated operation time counted in step S102 has exceeded a predetermined integrated operation time (set integrated operation time at or below the set frequency). In step S103, when the integration time counted in step S102 exceeds the set integration time (in the case of YES), the process proceeds to step S104, and oil return operation control is started from normal operation.

  When this oil return operation control is started, the compressor is forcibly stopped once for a predetermined time (inching time A). The inching time A is configured to be arbitrarily set, and since an energy saving effect can not be obtained if the time is unnecessarily long, the inching time A is set to be an optimal time.

  When the forced stop has passed the predetermined time, the process proceeds to step S105, and the forced operation of the compressor 1 is started. In step S105, the operating frequency of the compressor 1 is forcibly increased to the highest frequency, and in step S106, the operating time at the highest frequency is counted.

  In the following step S107, it is determined whether the operation time at the highest frequency counted in step S106 has exceeded a predetermined operation time (the set operation time at the highest rotational speed). If it is determined in step S107 that the counted operation time has exceeded the set operation time, the oil return operation control is ended and the process returns to the normal operation of step S101.

  On the other hand, if it is determined in step S107 that the counted operation time does not exceed the set operation time, the process proceeds to step S108, and the suction pressure Ps of the compressor detected by the suction pressure sensor 11 is set in advance. It is judged whether it is below the pressure value. Here, when it is determined that the suction pressure Ps is equal to or less than the set pressure value, the oil return operation control is stopped at that time, and the process returns to the step S101 and the normal operation is performed.

  Thus, in the general oil return operation control shown in FIG. 3, the operating frequency of the compressor 1 is increased regardless of the load state of the low-pressure equipment to temporarily increase the refrigerant circulation amount of the refrigeration cycle. By continuing this operation until a predetermined time passes (step S107 above) or until the suction pressure Ps becomes equal to or less than the set pressure value (step S108 above), the oil stagnating in the refrigeration cycle Is returned to the compressor 1. As a result, the oil remaining in the refrigeration cycle is returned to the compressor 1 to raise the oil level, and the compressor 1 is prevented from running out of oil.

However, in the oil return operation control shown in FIG. 3, sufficient consideration is not made to reliably return the oil staying in the refrigeration cycle to the compressor. That is, in the operation shown in FIG. 3, the operation frequency of the compressor 1 is increased to increase the refrigerant circulation amount of the refrigeration cycle, the oil return operation is stopped when the suction pressure Ps becomes equal to or less than the set pressure value. Since the operation is performed, the suction pressure Ps may fall below the set pressure value in a short time, for example, when the load is small. For this reason, the oil return operation can not be performed for the predetermined time which has been determined in advance, and the oil remaining in the refrigeration cycle can not be reliably returned to the compressor.
In particular, when the compressor continues to be operated at a low frequency or during a trial operation of a refrigeration system, a reduction in the amount of oil returned to the compressor is not taken into consideration.

  When the compressor continues to be operated at a low frequency, since the amount of refrigerant circulation is small, oil is particularly likely to stay in the refrigeration cycle, and the amount of oil returned to the compressor is reduced. For this reason, the amount of oil return decreases with respect to the amount of oil discharged from the compressor, and the oil in the compressor gradually decreases, and as a result, there is a possibility that the operation failure of the compressor may be caused.

  In particular, at the time of trial operation of the refrigeration system, since the load on the low pressure device side is also small, the operation of the compressor is continued at a low frequency, and the amount of returned oil decreases relative to the amount of oil discharged from the compressor. The oil decreases gradually, which is likely to cause the compressor to malfunction.

  As described above, even when the compressor continues to be operated at a low frequency due to the load condition of the low-pressure equipment, or at the time of trial operation of the refrigeration system where the operation of the compressor is easily continued at a low frequency, In order to perform the return and to improve the reliability of the compressor, in the present embodiment, the oil return control described below is performed.

  Hereinafter, the operation of oil return operation control in the refrigeration system of the present embodiment will be described using FIG. 2 with reference to FIG. FIG. 2 is a flow chart for explaining the operation of oil return operation control in the refrigeration system shown in FIG. In FIG. 2, the portions given the same reference numerals as the steps in FIG. 3 described above are the portions performing the same operations as in FIG. 3, and therefore the description of the steps for performing the same operations will be omitted or briefly described. .

The flow chart shown in FIG. 2 includes the oil return operation control in the test operation mode of the refrigeration system and the oil return operation control in the normal operation after the end of the test operation.
First, in step S201, when the operation switch of the refrigeration system I is turned ON (operation start), the process proceeds to step S202, normal operation in the test operation mode is started, and the suction side pressure detected by the suction pressure sensor 11 is preset. The frequency of the compressor 1 is controlled so as to fall within the allowable range of the set pressure, and suction pressure control following the change of the load condition of the low-pressure device III is performed.

  Even in this test operation mode, the operating frequency of the compressor 1 is monitored in order to monitor the amount of oil in the compressor 1 and to ensure a predetermined amount at all times. That is, in the next step S203, when the operating frequency becomes lower than the set frequency, the integrated operating time is counted.

  Next, the process proceeds to step S204, and it is determined whether or not the integration time (set integration time below the set frequency) for which the integration operation time counted in step S203 has been set has passed. In step S204, when the integration time counted in step S203 passes the set integration time (in the case of YES), the process proceeds to step S205, and from normal operation (suction pressure control) in trial operation mode to test operation mode. Oil return operation control is started.

On the other hand, in step S204, until the set integration time elapses (in the case of NO), the process proceeds to step S206, and the number of start / stop times of the compressor 1 is equal to or more than the set start / stop number If it is determined that the number is not less than the set number of start / stop times, the process proceeds to step S205 and oil return operation control is started.
In step S206, when the set start / stop frequency has not elapsed, the process returns to step S203, and the same operation is repeated.

  In step S205, when oil return operation control is started, first, the compressor 1 is forcibly stopped for a predetermined time (inching time B). The inching time B is longer than the inching time A described with reference to FIG. When the forced stop is over for a predetermined time, the forced operation of the compressor 1 is started. That is, the operating frequency of the compressor 1 is forcibly increased to the highest frequency, and the integration time of the operation at the highest frequency is counted.

  In the following step S207, it is determined whether or not the operation time at the highest frequency counted in the step S205 has exceeded a preset operation time (a set operation time at the highest rotational speed). If it is determined in step S207 that the counted operation time has exceeded the set operation time, the oil return operation control is ended, and the process proceeds to the next step S208, where the test operation mode is the same as step S202 described above. Normal operation is implemented.

  Thereafter, the process proceeds to step S209, and the oil return operation control in the test operation mode and the test operation mode in steps S203 to S208 described above is continued until the operation time (set test operation time) in the test operation mode set in advance passes. The controller 14 shown in FIG. 1 monitors the operation time in the trial operation mode from the operation switch ON, and is used for the determination in the step S209. Further, the set test operation time can be changed on the controller 14 side according to the state on the low pressure device III side.

  In this test operation mode, in consideration of carrying out the oil return operation under the condition that the influence of the load of test operation is small, as described above, the inching time B which is longer than the inching time A described in FIG. By lengthening the forced stop time of the compressor 1, it is possible to thermo-on all low-pressure equipment III systems. That is, the inching time B is set so that all the low pressure devices III connected to the refrigerator unit II can be thermo-oned. Thus, by setting the inching time B to be longer than the inching time A, the lubricating oil staying in all the refrigerant pipes (including the pipes of the heat exchanger) of the low-pressure device III connected is selected as the compressor 1 To be able to be collected.

  Since the inching time A is often set in consideration of achieving an energy saving effect as described above, only a part of the plurality of low pressure devices III connected to the refrigerator unit II may be thermo-oned. There is a possibility that the oil staying in the refrigeration cycle can not be fully returned to the compressor 1. In the trial operation mode, since it is carried out only for a limited period of test operation, emphasis is placed on securing the reliability of the compressor 1 rather than energy saving, and the inching time B is taken a long time Control is to be made.

  When the set trial run time has elapsed (in the case of YES) in step S209, the trial run mode is ended, and the process shifts to the normal operation in step S101. When shifting to this normal operation, operations similar to steps S101 to S107 described in FIG. 3 are performed, so the description of these steps S101 to S107 will be omitted, and portions where control different from that in FIG. .

  In the oil return operation control described with reference to FIG. 3, it has been described that the oil return operation control is ended when the suction pressure Ps becomes equal to or lower than the set pressure value in step S108, and the normal operation in step S101 is returned. On the other hand, in the present embodiment, when the suction pressure Ps, which is a detected value by the suction pressure sensor 11 shown in FIG. 1, becomes equal to or less than the set pressure value during the oil return operation control (in the case of YES). In step S109, the oil return retry operation is performed.

  That is, in step S109, the forcible stop of the compressor is carried out with the inching time B having a length similar to the inching time B in the test operation mode (a time longer than the inching time A in step S104). When the forced stop has passed for a predetermined time, the process proceeds to step S105, and the forced operation for operating the compressor 1 at the highest frequency is started, and the oil return operation is performed. Thereafter, the operation time at the highest frequency is counted (step S106), and in the subsequent step S107, the operation time at the highest frequency counted in the step S106 is preset operation time (set operation at the highest rotation speed) It is determined whether the time has elapsed. In step S107, the oil return retry operation of step S108 and step S109 is continued until the counted operation time exceeds the set operation time. In step S107, when the set operation time of the oil return operation control elapses, the oil return operation control is ended and the process returns to the normal operation of step S101.

  As described above, in the present embodiment, the oil return operation is performed again without ending the oil return operation control even if the suction pressure Ps becomes lower than the set pressure value until the set time of the oil return operation control elapses. It is controlled to perform the oil return retry operation to be performed.

  Further, when this oil return retry operation is performed, the inching time B for forcibly stopping the compressor is made longer than the inching time A in step S104, so the reduced suction pressure Ps is increased. , All connected low pressure equipment III can be thermo-on. As a result, the lubricant oil accumulated in the refrigerant pipes of all the connected low pressure devices can be recovered to the compressor 1.

  As described above, the present embodiment performs the oil return operation in the test operation mode, and also performs the oil return operation control and the oil return retry operation in the normal operation after the test operation mode, thereby Even in continuous operation for a long time, the lubricating oil accumulated in the refrigerant pipes of all the low pressure devices III connected to the refrigerator unit II can be recovered to the compressor 1. Accordingly, it is possible to maintain a good lubrication state by avoiding the lubrication failure due to the lack of the lubricating oil in the sliding portion of the compressor.

  As described above, according to the present embodiment, in the oil return operation in the test operation mode and the normal continuous operation (normal operation), the lubricating oil partially staying in the refrigeration cycle can be reliably maintained while maintaining cycle balance. It can be returned to. Thus, it is possible to obtain a refrigeration system capable of preventing exhaustion of lubricating oil in the compressor and maintaining a highly reliable operation at the time of operation in the test operation mode or at the time of normal operation with a low load of low pressure equipment.

  Moreover, according to the present embodiment, as in the conventional refrigeration system, the oil return operation can be carried out without providing a special detector such as an oil level sensor, and furthermore, the refrigeration can reliably return the oil to the compressor. The device can be obtained. Further, it is possible to obtain a refrigeration system capable of reliably returning the oil to the compressor even when the compressor is continuously operated at a low frequency or at the time of trial operation of the refrigeration system.

  In the embodiment described above, an example in which both the oil return operation in the test operation mode and the oil return operation in the normal operation are performed has been described, but the oil return operation described above only in the test operation mode or the normal operation Those that perform the oil return operation described above are also included in the scope of the present invention.

  Furthermore, the present invention is not limited to the above-described embodiments, and includes various modifications. Furthermore, the above-described embodiments are described in detail to illustrate the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described.

1 ... compressor (compression device), 2 ... condenser, 3 ... receiver, 4 ... air subcooling heat exchanger,
5 ... decompression device, 6 ... evaporator,
7: Liquid injection circuit 7a: Pressure reducing device
8: Flow control valve (flow control means),
11 ... suction pressure sensor, 12 ... discharge gas temperature sensor, 13 ... discharge pressure sensor,
14 ... controller, 20: refrigerant piping, 30 ... cooling fan,
I: Refrigeration device, II: Refrigeration unit, III: Low pressure device.

Claims (10)

A compressor capable of capacity control, a condenser for condensing the high pressure refrigerant compressed by the compressor, a decompression device for decompressing the high pressure refrigerant condensed by the condenser, and the refrigerant decompressed by the pressure reduction device In a refrigeration system in which a refrigeration cycle is configured by sequentially connecting a refrigerant to be evaporated and an evaporator to be evaporated,
A controller for controlling an operating capacity of the compressor;
The controller
A function of determining that the operation is performed at a low capacity that requires an oil return operation to the compressor and integrating the operation time at the low capacity;
A function of integrating the number of start / stop times of the compressor;
The oil return operation when the integrated operation time at the low capacity of the compressor passes a preset integration operation time or when the number of start / stop times of the compressor exceeds a preset start / stop number equipped with a function to perform control,
The oil return operation control is oil return operation control in a trial operation mode which is performed during a predetermined time (set trial operation time) which is determined in advance after the operation start of the refrigeration device.   The refrigeration system according to claim 1, wherein the oil return operation control returns the oil remaining in the refrigeration system to the compressor by starting the forced operation after executing a forced stop of the compressor for a predetermined time. A refrigeration apparatus characterized in that it is a control. The refrigeration system according to claim 2 , wherein the oil return operation control in the trial run mode is continued for the set trial run time.   The refrigeration system according to claim 3, wherein a plurality of low pressure devices are connected to the refrigeration cycle, and a forced stop time of the compressor in the oil return operation control is all connected to the refrigeration cycle. A refrigeration system characterized in that it is only possible to put a low pressure device in a thermo-on state. A compressor capable of capacity control, a condenser for condensing the high pressure refrigerant compressed by the compressor, a decompression device for decompressing the high pressure refrigerant condensed by the condenser, and the refrigerant decompressed by the pressure reduction device In a refrigeration system configured by sequentially connecting a refrigerant pipe to a vaporizing evaporator with a refrigerant pipe,
A controller for controlling an operating capacity of the compressor;
The controller
A function of determining that the operation is performed at a low capacity that requires an oil return operation to the compressor and integrating the operation time at the low capacity;
A function of performing an oil return operation control for starting forced operation after forcibly stopping the compressor when an integrated operation time at the low capacity of the compressor passes a preset integrated operation time;
The oil return retry operation for starting the forced operation after forcedly stopping the compressor when the suction side pressure of the compressor becomes equal to or less than a predetermined set pressure value during the oil return operation control, the oil A refrigeration system having a function to perform until a set operation time of return operation control elapses.   The refrigeration system according to claim 5, wherein a plurality of low pressure devices are connected to the refrigeration cycle, and a forced stop time (inching time B) of the compressor in the oil return retry operation is the oil return operation control. A refrigeration apparatus characterized in that the time is set to be longer than the forced stop time (inching time A) of the compressor. The refrigeration system according to any one of claims 1 to 6, wherein the operating frequency of the compressor is predetermined when it is determined that the compressor is operated at a low capacity that requires an oil return operation to the compressor. refrigeration system characterized in that it is carried out by being operated at less than the set frequency. The refrigeration system according to claim 1 or 5, wherein the controller comprises both the oil return operation control function according to claim 1 and the oil return operation control function according to claim 5, and the operation of the refrigeration apparatus The oil return operation control according to claim 1 is performed in a test operation mode performed during a predetermined time (set test operation time) predetermined from the start, and in the normal operation after the test operation mode ends. A refrigeration system for performing the oil return operation control according to claim 1. A refrigerator unit comprising: a compressor capable of capacity control; and a condenser for condensing high pressure refrigerant compressed by the compressor.
A controller for controlling an operating capacity of the compressor;
Wherein the controller,
A function of determining that the operation is performed at a low capacity that requires an oil return operation to the compressor and integrating the operation time at the low capacity;
A function of integrating the number of start / stop times of the compressor;
The oil return operation when the integrated operation time at the low capacity of the compressor passes a preset integration operation time or when the number of start / stop times of the compressor exceeds a preset start / stop number equipped with a function to perform control,
A refrigerator unit characterized in that the oil return operation control is oil return operation control in a trial operation mode which is carried out during a predetermined time (set trial operation time) which is predetermined from the start of operation of the refrigeration system . A refrigerator unit comprising: a compressor capable of capacity control; and a condenser for condensing high pressure refrigerant compressed by the compressor.
A controller for controlling an operating capacity of the compressor;
The controller
A function of determining that the operation is performed at a low capacity that requires an oil return operation to the compressor and integrating the operation time at the low capacity;
A function of performing an oil return operation control for starting forced operation after forcibly stopping the compressor when an integrated operation time at the low capacity of the compressor passes a preset integrated operation time;
The oil return retry operation for starting the forced operation after forcedly stopping the compressor when the suction side pressure of the compressor becomes equal to or less than a predetermined set pressure value during the oil return operation control, the oil A refrigerator unit having a function to perform until a set operation time of return operation control elapses.

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