JP2012202590A - Refrigerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency by preventing a compressor from being operated with a capacity beyond necessity.SOLUTION: This refrigerating device includes a condensing unit including the compressor and a condenser, a plurality of refrigerator including coolers having expansion valves, solenoid valves for refrigerant liquid, and evaporators, inside temperature sensors respectively disposed in the refrigerators, cooler control devices for adjusting the inside temperature by controlling the solenoid valve for refrigerant liquid to a thermo-on state or a thermo-off state by comparing the temperature detected by the inside temperature sensor and set thermo-on temperature and thermo-off temperature, an intake pressure sensor detecting a pressure at an intake side of the compressor, and a condensing unit control device controlling the compressor by comparing the intake pressure detected by the intake pressure sensor and a target intake pressure. The target intake pressure of the condensing unit control device is determined on the basis of a set temperature of the refrigerator in the thermo-on state among the plurality of refrigerators (coolers 11, 15, 19).

Description

  The present invention relates to a refrigeration apparatus including a plurality of refrigerators and freezers, and more particularly to a refrigeration apparatus capable of individually setting a thermo-on set temperature and a thermo-off set temperature with the plurality of refrigerators and freezers.

  In the refrigeration apparatus, a condensing unit including a compressor and a condenser, and a cooler including an expansion valve, a refrigerant liquid electromagnetic valve, and an evaporator are connected by a refrigerant pipe to form a refrigeration cycle. The inside of the refrigerator or freezer is cooled. In the following description, a refrigerator, a freezer, a showcase installed in a store, etc. are collectively referred to as a refrigerator. In the refrigerator, the target suction pressure of the compressor is determined based on the set temperature. As this kind of prior art, there is one described in Patent Document 1, for example.

  The thing of patent document 1 is provided with the cooler control apparatus which controls a cooler, and the condensing unit control apparatus which controls a condensing unit, and describes controlling a refrigerating apparatus. That is, the cooler control device stores a thermo-on set temperature and a thermo-off set temperature in advance, and the cooler control device stores the internal temperature detected by the internal temperature sensor, the thermo-on set temperature, and the thermo-off set temperature. When the internal temperature exceeds the thermo-on set temperature, the operation start command signal is output to the cooler. As a result, the solenoid valve for the refrigerant liquid is opened, and the blower is driven to send air to the evaporator and circulate the air cooled by the evaporator in the refrigerator. When the internal temperature becomes lower than the thermo-off set temperature, the cooler control device outputs an operation stop command signal to the cooler. As a result, the refrigerant liquid solenoid valve is closed, and the blower is stopped.

  On the other hand, the condensing unit control device variably controls the rotational speed of the compressor based on the suction pressure of the compressor. That is, the controller for the condensing unit stores the upper limit set pressure and the lower limit set pressure in advance, and compares the compressor suction pressure detected by the suction pressure sensor with the upper limit set pressure and the lower limit set pressure. Then, the rotational speed of the compressor is variably controlled through an inverter according to the comparison result. For example, if the suction pressure is greater than or equal to the upper limit set pressure, the compressor speed is increased. If the suction pressure is less than the upper limit set pressure and higher than the lower limit set pressure, the compressor speed is maintained and When the pressure is equal to or lower than the lower limit set pressure, control is performed so as to decrease the rotational speed of the compressor.

  Furthermore, the thing of the patent document 1 also describes having comprised so that the said thermo-on preset temperature and thermo-off preset temperature can be changed.

JP 2010-175203 A

  In a relatively large refrigeration apparatus in which the condensing unit installed outdoors or the like and the cooler installed indoors are connected by a refrigerant pipe, as described above, the cooler Is provided with a cooler control device, and the condensing unit is provided with a condensing unit control device, which are generally controlled independently. That is, temperature adjustment in the refrigerator is performed by the cooler control device, and suction pressure adjustment of the compressor is performed by the condensing unit control device.

  Although the target value (target suction pressure) of the suction pressure of the compressor is determined by the set temperature of the refrigerator, a plurality of refrigerators (coolers) are connected to one condensing unit, and the plurality of refrigerators are individually cooled. In many cases, the set temperature of each refrigerator is different. If the evaporation temperature of the evaporator in the cooler is higher than the set temperature of the refrigerator, the refrigerator cannot be cooled to the set temperature. Therefore, in the conventional refrigeration apparatus, the lowest set temperature among the set temperatures in the plurality of refrigerators is set. The target suction pressure of the condensing unit is set and controlled with respect to the set temperature.

  For this reason, even if the refrigerator with the low set temperature is thermo-off and only the refrigerator with the other set temperature is in the thermo-on state, the target suction pressure of the condensing unit is the target suction pressure that matches the lowest set temperature. It is always driven. Therefore, the suction pressure of the compressor is controlled to be lower than necessary, and the compressor is operated with a capacity larger than necessary, which causes a problem of reducing the efficiency of the refrigeration apparatus.

  An object of the present invention is to obtain a refrigeration apparatus capable of improving efficiency by improving that a compressor is operated at a capacity larger than necessary.

  In order to achieve the above object, the present invention provides a condensing unit including a compressor and a condenser, a plurality of refrigerators including an expansion valve, an electromagnetic valve for refrigerant liquid, and a cooler having an evaporator, An internal temperature sensor provided in the refrigerator for detecting the internal temperature, the temperature detected by the internal temperature sensor, the set thermo-on temperature and the thermo-off temperature are compared, and the refrigerant liquid solenoid valve is A cooler control device that adjusts the internal temperature by controlling in a thermo-on state or a thermo-off state, a suction pressure sensor that detects a pressure on the suction side of the compressor, a suction pressure detected by the suction pressure sensor, and a target suction In a refrigeration apparatus comprising a condensing unit control device that controls the compressor by comparing pressure, based on a set temperature of a refrigerator that is in a thermo-on state among the plurality of refrigerators Wherein the target suction pressure of the condensing unit controller is set.

  According to the present invention, since the target suction pressure of the condensing unit control device is set based on the set temperature of the refrigerator in the thermo-on state among the plurality of refrigerators, the compressor is operated with a capacity larger than necessary. It is possible to prevent the occurrence of the refrigeration apparatus and to obtain a refrigeration apparatus capable of improving the efficiency.

The refrigeration cycle block diagram which shows the whole structure of the freezing apparatus in Example 1 of this invention. The figure explaining the view of the setting of the setting pressure with respect to the setting temperature in Example 1 of this invention. The figure explaining the specific example of a setting of the target suction pressure in a condensing unit control apparatus. The figure explaining the change process of the target suction pressure in Example 1 of this invention.

  Hereinafter, specific embodiments of the refrigeration apparatus of the present invention will be described with reference to the drawings.

  FIG. 1 is a refrigeration cycle configuration diagram showing the overall configuration of a refrigeration apparatus in Embodiment 1 of the present invention. A single condensing unit 7 is connected to a plurality of refrigerators (freezers) via a high-pressure refrigerant pipe 20 and a low-pressure refrigerant pipe 21. 1 to 3) are also connected.

  The condensing unit 7 condenses and liquefies the high-pressure gas refrigerant by the compressor 4 configured to be controlled in rotation speed by an inverter, and the high-pressure refrigerant compressed by the compressor is guided and exchanged with outside air or the like. A condenser 5, a suction pressure sensor 22 for detecting the pressure on the suction side of the compressor 4, a suction gas temperature sensor 23 for detecting a temperature on the suction side, the suction pressure sensor 22 and the suction gas. A condensing unit control device 6 for controlling the compressor 4 based on the detection value of the temperature sensor 23 is provided.

  The refrigerator 1 includes a refrigerant liquid electromagnetic valve 8 and an expansion valve 9 provided in a high pressure liquid pipe connected to the high pressure refrigerant pipe 20, an evaporator 10 provided on the downstream side of the expansion valve 9, and the like. The cooler 11, the internal temperature sensor 25 for detecting the temperature in the refrigerator 1, the cooler control device 24 for controlling the refrigerant liquid electromagnetic valve 8 based on the detected value of the internal temperature sensor 25, and the like. ing. A remote controller 31 is connected to the cooler control device 24, and a thermo-on temperature and a thermo-off temperature of the refrigerator 1 can be set from the remote controller.

  The cooler control device 24 compares the thermo-on temperature and the thermo-off temperature set by the remote controller 31 with the internal temperature detected by the internal temperature sensor 25, so that the internal temperature is higher than the thermo-on temperature. Then, the refrigerant liquid electromagnetic valve 8 is opened to be in a thermo-on state. In this thermo-on state, the liquid refrigerant from the condensing unit 7 is introduced and decompressed by the expansion valve 9, and the low-pressure and low-temperature refrigerant evaporates by taking the heat of evaporation from the air in the refrigerator in the refrigerator 1 in the evaporator 10. It becomes a low-pressure refrigerant gas. This low-pressure refrigerant gas is sucked into the compressor 4 of the condensing unit 7 through the low-pressure refrigerant pipe 21.

  When the refrigerator 1 is cooled by entering the thermo-on state and the temperature detected by the internal temperature sensor 25 becomes lower than the thermo-off temperature set by the cooler control device 24, the cooler In accordance with a command from the control device 24, the refrigerant liquid solenoid valve 8 is closed. In this thermo-off state, since the introduction of the liquid refrigerant from the condensing unit 7 is stopped, the cooling of the refrigerator 1 is also stopped. When the cooling of the refrigerator 1 is stopped and the internal temperature rises again and exceeds the thermo-on temperature, the same operation as described above is repeated.

The other refrigerators 2 and 3 have the same configuration as the refrigerator 1 and operate in the same manner as the refrigerator 1.
That is, the refrigerator 2 includes a cooler 15 including a refrigerant liquid solenoid valve 12, an expansion valve 13, and an evaporator 14, a cooler control device 26, an internal temperature sensor 27, a remote controller 32, and the like. Similarly, the refrigerator 3 includes a cooler 15 including a refrigerant liquid electromagnetic valve 16, an expansion valve 17, and an evaporator 18, a cooler control device 28, an internal temperature sensor 29, and a remote controller 33.
In FIG. 1, T1, T2, and T3 are set temperatures in the refrigerator in each refrigerator.

  Further, the condensing unit control device 6 and the cooler control devices 24, 26, and 28 provided in the refrigerators 1 to 3, respectively, are connected to each other via a communication line 30, and in each of the refrigerators 1 to 3, respectively. The set thermo-on temperature and thermo-off temperature and the operation information as to whether each of the refrigerators 1 to 3 is in the thermo-on state or the thermo-off state are transmitted to the condensing unit control device 6 constantly or at a necessary timing.

  Since the thermo-off set temperatures of the refrigerators 1 to 3 are generally set to different temperatures, an evaporation pressure adjusting valve is installed on the outlet side of the refrigerant pipe in each of the coolers 11, 15, 19, and each thermo-off is set. You may make it adjust the pressure in an evaporator so that it may become an evaporation pressure suitable for preset temperature.

  The condensing unit control device 6 sets a target suction pressure, and controls the rotation speed (operating frequency) of the compressor 4 so that the value detected by the suction pressure sensor 22 falls within the set range of the target suction pressure. To do.

  In this embodiment, the target suction pressure is set based on a set temperature of a refrigerator that is in a thermo-on state among the plurality of refrigerators 1 to 3. That is, the condensing unit control device 6 monitors whether the plurality of refrigerators are in a thermo-on state or a thermo-off state, and also monitors a set temperature in each refrigerator to set a set temperature of the refrigerator in the thermo-on state. Among these, the target suction pressure in the condensing unit control device 6 is set (automatically adjusted) in correspondence with the set temperature of the refrigerator set to the lowest.

  The target suction pressure has an upper limit set pressure PsU and a lower limit set pressure PsD. When the suction pressure detected by the suction pressure sensor 22 is equal to or higher than the upper limit set pressure PsU, the condensing unit control device 6 increases the operating frequency of the compressor, and the suction pressure is set to the upper limit set. When the pressure is less than the pressure and higher than the lower limit set pressure PsD, the capacity of the compressor is maintained, and when the suction pressure is less than or equal to the lower limit set pressure PsD, the operation frequency of the compressor is controlled to be decelerated. To do. As a result, it is configured to be maintained within the range of the target suction pressure.

  The refrigerant liquid solenoid valves 8, 12, 16 of all the coolers 11, 15, 19 are all closed, and a predetermined stop pressure at which the suction pressure detected by the suction pressure sensor 22 is lower than the lower limit set pressure PsD. When it falls to A, the refrigeration apparatus (compressor) is stopped.

  In the condensing unit control device 6 and the cooler control devices 24, 26, and 28, the internal temperature detected by the internal temperature sensors 25, 27, and 29, the cooler control devices 24, 26, and 28 The set thermo-on temperature, the thermo-off temperature, the suction pressure detected by the suction pressure sensor 22, the suction gas temperature detected by the suction gas temperature sensor 23, and the target suction pressure (set by the condensing unit controller 6) Information such as an upper limit set pressure PsU and a lower limit set pressure PsD) is shared, and the refrigeration apparatus is controlled.

  In this embodiment, the target suction pressure is set in accordance with the lowest set temperature of the refrigerator set temperature in the thermo-on state. A method of setting the target suction pressure in the condensing unit control device 6 with respect to temperature will be described below with reference to FIGS.

  Among the refrigerators in the thermo-on state, the target suction pressure (upper limit set pressure PsU, lower limit set pressure PsD) on the condensing unit controller 6 side for the thermo-off temperature and the thermo-on temperature set in the refrigerator with the lowest set temperature. The concept of setting will be described with reference to FIG.

  The upper limit set pressure PsU is set so that the target suction pressure corresponds to a temperature lower than the thermo-on temperature Ton in the refrigerator set to the lowest thermo-off temperature among the refrigerators in the thermo-on state, for example, 1 ° C. lower. The Further, the lower limit set pressure PsD is set so as to correspond to a temperature higher than the thermo-off temperature Toff of the refrigerator, for example, a temperature higher by 1 ° C. By setting the target suction pressure value in this way, for example, when the thermo-on temperature is 4 ° C., the upper limit set pressure PsU is set so as to correspond to 3 ° C., which is 1 ° C. lower than that, so When it becomes 4 degreeC and the said solenoid valve for refrigerant | coolants liquid opens, it can suppress that the internal temperature becomes higher than 4 degreeC.

Further, when the thermo-off temperature is 0 ° C., the lower limit set pressure PsD is set so as to correspond to 1 ° C. higher by 1 ° C. Therefore, the internal temperature becomes 0 ° C. and the refrigerant liquid solenoid valve is closed. In this case, the internal temperature can be suppressed from becoming lower than 0 ° C. Thus, it is devised so that the internal temperature is maintained within the set temperature range as much as possible.
In FIG. 2, A is an operation stop pressure value set to a pressure lower than the lower limit set pressure PsD.

  Next, a specific setting example of the target suction pressure in the condensing unit control device 6 will be described with reference to FIG. The refrigerator which is set to the lowest thermo-off temperature among the refrigerators in the thermo-on state has a thermo-on temperature Ton of 4 ° C and a thermo-off temperature Toff of 0 ° C. In general, when the set temperature in the cabinet is 0 ° C., the thermo-off temperature is matched with the set temperature. The thermo-on temperature is set a few degrees higher than the thermo-off temperature. In this embodiment, it is set to 4 ° C.

  In order to maintain the temperature in the refrigerator at the set temperature, the temperature (evaporation temperature) of the cooler needs to be about 10 ° C. lower than the set temperature. Accordingly, the temperature of the cooler corresponding to the thermo-off temperature 0 ° C. is −10 ° C., and the temperature of the cooler corresponding to the thermo-on temperature 4 ° C. is −6 ° C. The target suction pressure in the condensing unit control device 6 is determined so that such a temperature can be obtained by the cooler. However, as described with reference to FIG. 2, the inside temperature becomes lower than the thermo-off temperature 0 ° C., In order to prevent the thermo-on temperature from becoming higher than 4 ° C., the suction pressure value is determined so that the lower limit set pressure PsD becomes a saturation temperature of −9 ° C., which is 1 ° C. higher than the −10 ° C. Further, the suction pressure value is determined so that the upper limit set pressure PsU has a saturation temperature of −7 ° C. which is 1 ° C. lower than the −6 ° C.

  FIG. 4 is a diagram for explaining the target suction pressure changing process in the first embodiment of the present invention. In this embodiment, a plurality of refrigerators 1 to 3 are connected to one condensing unit 7, and each refrigerator is set to a different set temperature T1, T2, T3 (T1 <T2 <T3). It is assumed that the thermo-on temperature and the thermo-off temperature are set by the respective cooler control devices 24, 26, and 28 and are operated by repeating the thermo-on state and the thermo-off state.

  The target suction pressures corresponding to the set temperatures T1, T2, and T3 of the refrigerators 1 to 3 are aMPa, bMPa, and cMPa, and the upper limit set pressure PsU and the lower limit set pressure PsD are determined for each target suction pressure. Suppose that the compressor 4 is controlled in rotational speed.

  That is, the set temperature of the refrigerator 1 is T1, the evaporation pressure (saturation pressure) necessary for the cooler 11 to obtain this set temperature state is aMPa, and similarly, the set temperature of the refrigerator 2 is T2. The evaporating pressure (saturation pressure) necessary for the cooler 15 to obtain the set temperature state is bMPa, and the set temperature of the refrigerator 3 is T3. The evaporating pressure necessary for the cooler 19 to obtain this set temperature state The (saturation pressure) is cMPa. Here, the evaporation pressures a, b, and c are in a relationship of a <b <c.

  First, if the refrigerator 1 is in the thermo-on state (the cooler 11 is in operation), the refrigerators 2 and 3 are in the thermo-on state and in the thermo-off state (whether the coolers 15 and 19 are in operation / stopped), and the target suction pressure is the highest. Set to low aMPa. The condensing unit 7 is operated at the target suction pressure aMPa suitable for the cooler 11 by setting the upper limit set pressure PsU and the lower limit set pressure PsD for the target suction pressure aMPa with the condensing unit control device 6 and operating. Can do.

  Next, when the refrigerator 1 is in the thermo-off state (the cooler 11 is stopped) and the refrigerator 2 is in the thermo-on state (the cooler 15 is in operation), the refrigerator 3 is in either the thermo-on state or the thermo-off state (the cooler 19 is in operation / In any case of stopping, the target suction pressure is set to an intermediate pressure bMPa, and similarly, the operation can be performed at the target suction pressure bMPa suitable for the cooler 15. That is, the condensing unit 7 is operated with the upper limit set pressure PsU and the lower limit set pressure PsD for the target suction pressure bMPa.

  Further, when the refrigerators 1 and 2 are thermo-off (the coolers 11 and 15 are stopped) and only the refrigerator 3 is thermo-on (the cooler 19 is operated), the target suction pressure is set to the highest pressure cMPa. In addition, it can be operated at a target suction pressure cMPa suitable for the cooler 19.

  As described above, in this embodiment, the target suction pressure is set in accordance with the set temperature of the refrigerator set lowest among the set temperatures of the refrigerator in the thermo-on state. The suction pressure is not controlled to be lower than necessary, and the compressor can be prevented from being operated at a capacity larger than necessary. Therefore, the efficiency of the refrigeration apparatus can be improved.

  In addition, it is possible to prevent the evaporation temperature from becoming lower than necessary for refrigerators with a high set temperature, so that the difference between the evaporation temperature and the internal temperature can be prevented from becoming too large, and frost formation on the cooler progresses. Can also be suppressed. Therefore, the effect that the time for defrosting can also be reduced is acquired.

  In this embodiment, an example in which three refrigerators 1 to 3 are connected to one condensing unit 7 has been described. However, the present invention can be similarly applied as long as there are a plurality of refrigerators. The number of condensing units is not limited to one, and a plurality of condensing units may be used.

  Further, in the present embodiment, the compressor 4 is described as performing the capacity control by changing the operation frequency with an inverter or the like, but a plurality of constant speed compressors are mounted on one condensing unit 7, Capacity control may be performed by controlling the number of units. In this case, one of the plurality of compressors may be a variable operating frequency type.

Regarding the control of the compressor in the condensing unit control device 6, in the first embodiment, when the suction pressure detected by the suction pressure sensor 22 is equal to or higher than the upper limit set pressure PsU, the operating frequency of the compressor is set. Although the speed is increased, the operating capacity is gradually increased, such as “25 Hz → 30 Hz →... → 75 Hz”.
Also, when the capacity increases due to the number of operating compressors, the operating capacity is gradually increased by increasing the operating number one by one, such as “1 → 2 → 3”.

  However, when the number of coolers (refrigerators) in the thermo-on state is increased, in the control for gradually increasing the operation capacity of the compressor, it takes a long time to reach the set temperature.

  Therefore, in this embodiment, the compressor operating capacity (operating frequency and operating number) corresponding to the number of coolers in the thermo-on state is set in the condensing unit controller 6 in advance, and the thermo-on state is established. According to the number of coolers, the operating capacity (operating frequency or operating number) of the compressor is controlled to correspond to a preset operating capacity.

  For example, when the number of refrigerator coolers in the thermo-on state is one and the operating frequency of the compressor is 25 Hz, the number of refrigerator coolers in the thermo-on state is increased to three. The operation frequency is controlled to increase from 25 Hz to 75 Hz at a stretch.

  When the compressor capacity is controlled by the number of operating compressors, the number of operating compressors is increased from one to three at a stretch.

  Similarly, when the number of refrigerator coolers in the thermo-on state decreases, similarly, the operation capacity of the compressor is controlled to decrease according to the number of coolers in the thermo-on state.

In this way, the capacity of the compressor is controlled according to the number of refrigerator coolers in the thermo-on state, so that the condensing unit 7 can be operated close to the optimum capacity at a stroke. It is possible to improve the follow-up performance of the capacity control. Further, along with this, the efficiency of the refrigeration apparatus can be further improved.
In the second embodiment, the other configuration is the same as that of the first embodiment, and a description thereof will be omitted.

  According to each embodiment of the present invention described above, the target suction pressure of the condensing unit control device is set based on the set temperature of the refrigerator in the thermo-on state among the plurality of refrigerators, so that the compressor is more than necessary. Operation with a large capacity can be prevented, and the effect of improving the efficiency of the refrigeration apparatus can be obtained.

1-3: refrigerator (including freezer, showcase, etc.),
4: Compressor,
5: Condenser,
6: Condensing unit control device,
7: Condensing unit,
8, 12, 16: Solenoid solenoid valve,
9, 13, 17: expansion valve,
10, 14, 18: evaporator,
11, 15, 19: cooler,
20: high-pressure refrigerant piping,
21: low-pressure refrigerant piping,
22: Suction pressure sensor,
23: Intake gas temperature sensor,
24, 26, 28: cooler control device,
25, 27, 29: Internal temperature sensor,
30: Communication line.

Claims (5)

To detect a condensing unit having a compressor and a condenser, a plurality of refrigerators having an expansion valve, an electromagnetic valve for refrigerant liquid, and an evaporator, and an internal temperature provided in each of the refrigerators Compare the temperature detected by the internal temperature sensor, the temperature detected by the internal temperature sensor, the set thermo-on temperature, and the thermo-off temperature, and control the refrigerant liquid solenoid valve to the thermo-on state or thermo-off state. A cooler control device for adjusting the temperature, a suction pressure sensor for detecting the pressure on the suction side of the compressor, and comparing the suction pressure detected by the suction pressure sensor with a target suction pressure to control the compressor A refrigeration apparatus comprising a condensing unit control device for
A refrigerating apparatus, wherein a target suction pressure of the condensing unit control device is set based on a set temperature of a refrigerator in a thermo-on state among the plurality of refrigerators.   2. The refrigeration apparatus according to claim 1, wherein the target suction pressure has an upper limit set pressure PsU and a lower limit set pressure PsD, and the compressor is a compressor capable of capacity control by changing an operating frequency. The condensing unit controller increases the operating frequency of the compressor when the suction pressure detected by the suction pressure sensor is equal to or higher than the upper limit set pressure PsU, and the suction pressure is less than the upper limit set pressure. When the pressure is higher than the lower limit set pressure PsD, the operation frequency of the compressor is maintained, and when the suction pressure is lower than the lower limit set pressure PsD, the operation frequency of the compressor is decreased. A refrigeration apparatus configured to have a target suction pressure.   2. The refrigeration apparatus according to claim 1, wherein the target suction pressure has an upper limit set pressure PsU and a lower limit set pressure PsD, and the compressor is composed of a plurality of compressors, and the condensing unit control is performed. The apparatus increases the number of operating compressors when the suction pressure detected by the suction pressure sensor is equal to or higher than the upper limit set pressure PsU, and the suction pressure is less than the upper limit set pressure and higher than the lower limit set pressure PsD. In this case, the operation number of the compressors is maintained, and when the suction pressure is equal to or lower than a lower limit set pressure PsD, control is performed so as to decrease the operation number of the compressors so that the target suction pressure is obtained. A refrigeration apparatus characterized by   4. The refrigeration apparatus according to claim 2, wherein the target suction pressure is set to a lowest thermo-off temperature among a plurality of refrigerators connected to the condensing unit in a thermo-on state. The refrigeration apparatus, wherein the upper limit set pressure PsU is set so as to correspond to a temperature lower than a thermo-on temperature, and the lower limit set pressure PsD is set so as to correspond to a temperature higher than a thermo-off temperature of the refrigerator.   In the refrigeration apparatus according to claim 1, in the condensing unit control device, an operating capacity of a compressor corresponding to the number of the coolers provided in the refrigerator in a thermo-on state is set in advance. The refrigeration apparatus characterized by controlling the operating capacity of the compressor in accordance with a preset operating capacity in accordance with the number of coolers in the thermo-on state.

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