JP5735441B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigeration apparatus including a compressor whose capacity can be controlled, and more particularly to a refrigeration apparatus having an operating range in a standard specification region having a low evaporation temperature and a high temperature specification region having a high evaporation temperature.

As a conventional refrigeration apparatus provided with a capacity-controllable compressor, there is one described in JP 2011-141104 A (Patent Document 1). The thing of this patent document 1 describes controlling a compressor capacity | capacitance so that the evaporation temperature of a refrigerant | coolant may become the temperature exceeding the critical temperature which refrigeration oil and a refrigerant | coolant isolate | separate.
Further, in the refrigeration apparatus, it is known that the capacity control of the compressor is performed by adjusting the drive frequency with an inverter power supply.

JP 2011-141104 A

  In the refrigeration system that controls the operating frequency of the compressor by the inverter power supply, the target evaporation temperature (ET) is generally in the operating range of about −20 ° C. to −5 ° C. (the operating range in the standard specification range). Yes. In such a refrigeration apparatus, the capacity of the condenser is designed based on the case where the evaporation temperature is −5 ° C.

  Recently, there is a demand for a refrigeration apparatus that can be used even in a high temperature region (high temperature specification region) where the evaporation temperature exceeds −5 ° C. for storage of vegetables, fruits, medicines, and the like. However, in the high temperature range where the evaporation temperature exceeds -5 ° C, the condensation capacity of the condenser is exceeded, and the condensation capacity tends to be insufficient. For this reason, the discharge pressure on the compressor discharge side rises and the high pressure rises abnormally. Or, due to an abnormal increase in operating current, the protection control may be activated and the compressor of the refrigeration apparatus may be stopped. In this case, there is a problem that the operation of the refrigeration apparatus becomes impossible.

  The object of the present invention is a refrigeration capable of operating with higher condensing capacity while suppressing the activation of protection control even in a high temperature specification region where the evaporation temperature is higher than the operation range in the standard specification region. To get the device.

  In order to achieve the above object, the present invention provides a refrigeration apparatus including a compressor and a condenser capable of controlling capacity, a discharge pressure sensor for detecting a discharge pressure of the compressor, and a discharge side temperature of the compressor. At least one of a discharge temperature sensor and an outside air temperature sensor that detects an outside air temperature, an intake pressure sensor that detects an intake pressure of the compressor, an operating range in a standard specification region where the evaporation temperature is low, and the standard The operation range in the high temperature specification region having a higher evaporation temperature than the specification region, and in the operation range in the high temperature specification region, the upper limit value of the compressor capacity is set according to the target evaporation temperature, and the upper limit value is When the upper limit is changed, the compressor is controlled so as not to exceed the upper limit capacity according to the changed upper limit when the upper limit is changed. And wherein the Rukoto.

  According to the present invention, even in a high temperature specification region where the evaporation temperature is a high temperature exceeding the operation range in the standard specification region, the refrigeration capable of operating with higher condensing capacity while suppressing the activation of protection control. A device can be obtained.

The refrigeration cycle system | strain diagram which shows Example 1 of the freezing apparatus of this invention. The diagram which shows the relationship between target evaporation temperature (target suction pressure) and the upper limit of an operating frequency. The diagram which shows the relationship between the target evaporation temperature (target suction pressure) when the outside air temperature is considered and the upper limit value of the operating frequency. It is a figure explaining Example 2 of this invention, and is a diagram which shows the relationship between the target evaporation temperature (target suction pressure) at the time of considering the protection control conditions of a freezing apparatus, and the upper limit of an operating frequency.

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

A first embodiment of the refrigeration apparatus of the present invention will be described with reference to FIGS.
FIG. 1 is a refrigeration cycle system diagram showing Embodiment 1 of the refrigeration apparatus of the present invention. In FIG. 1, I is an air-cooled integrated refrigeration apparatus, and II is a low-pressure side device that is connected to the refrigeration apparatus I and constitutes a refrigeration cycle. The refrigeration apparatus I and the low-pressure side device II are connected to each other by pipe connection portions 17 and 18 through refrigerant pipes.

  In the refrigeration apparatus I, reference numeral 1 denotes a compressor whose capacity can be controlled, and in this embodiment, the inverter compressor whose capacity is controlled by changing the drive frequency by an inverter power supply. In addition, it is good also as a compressor which can carry out capacity | capacitance control by connecting several constant speed compressors and controlling the number of drives. In FIG. 1, 2 is a condenser, 3 is a supercooler, and the condenser 2 and the supercooler have an integral structure. 5 is a liquid receiver provided in the middle of a refrigerant pipe connecting the condenser 2 and the supercooler 3, and 14 is a blower fan for blowing outside air to the condenser 2 and the supercooler 3. It is.

  The high-temperature and high-pressure refrigerant gas discharged from the compressor 1 enters the condenser 2 and is condensed by being cooled by the outside air blown from the blower fan 14. The condensed liquid refrigerant is stored in the liquid receiver 5, from which only the liquid refrigerant is led to the supercooler 3, where it is supercooled, and then sent to the low-pressure device II side through the refrigerant pipe (liquid pipe). It is done. The refrigerant pipe downstream of the supercooler 3 is provided with a dryer 9 for removing moisture contained in the liquid refrigerant and a sight glass 8 for confirming the state of the liquid refrigerant.

  The supercooled liquid refrigerant sent to the low-pressure side device II side passes through the electromagnetic valve 7, is depressurized by the expansion valve 6, becomes low temperature and low pressure, enters the evaporator 4, and is sent from the blower fan 15. It evaporates by exchanging heat with the generated air. The evaporated gas refrigerant then returns to the refrigeration apparatus I side through the refrigerant pipe (gas pipe), is sucked into the compressor 1 through the accumulator 13, and is compressed and discharged again. Reference numeral 16 denotes an external heater provided in the low-pressure device II.

  In this embodiment, the refrigerant pipe between the dryer 9 downstream of the supercooler 3 and the sight glass 8 and the compressor 1 are connected by a liquid injection pipe 10, and the liquid injection pipe 10 includes An expansion valve 11 and an electromagnetic valve 12 for adjusting the liquid injection amount are provided. The compressor 1 of the present embodiment is formed of a scroll compressor, and a compression chamber (suction pressure and discharge) in the middle of compression formed by the fixed scroll and the orbiting scroll meshing with each other and the orbiting scroll orbiting. The liquid injection pipe 10 is connected to a compression chamber at a portion that is an intermediate pressure between the pressure and the pressure.

  By liquid-injecting liquid refrigerant into the compression chamber, the temperature of the compressed refrigerant gas discharged from the compressor 1 can be kept below a certain temperature. Accordingly, a discharge temperature sensor 105 for detecting the temperature on the discharge side of the compressor (or the temperature of the compressor) is provided, and the electromagnetic valve 12 is opened and closed or the expansion is performed according to the detected value from the discharge temperature sensor 105. The opening of the valve 11 is configured to be controlled.

  101 is a control device for controlling the compressor 1, the expansion valve 11 and the electromagnetic valve 12, 102 is a suction pressure sensor for detecting the suction pressure of refrigerant sucked into the compressor 1, and 103 is for detecting the outside air temperature. An outside air temperature sensor 104 is a discharge pressure sensor for detecting the pressure of the high-pressure gas refrigerant discharged from the compressor 1. Detection values detected by the suction pressure sensor 102, the outside air temperature sensor 103, the discharge pressure sensor 104, the discharge temperature sensor 105, and the like are input to the control device 101, and the control device 101 is based on these detection values. The number of rotations of the compressor (in the case of a compressor having a plurality of compressors whose capacity is controlled) is controlled, and the circulation amount of the refrigerant discharged from the compressor is controlled.

In the control device 101, an upper limit value of the compressor capacity (operating frequency or operating number of compressors) of the compressor 1 is set in accordance with a target evaporation temperature (target suction pressure).
For example, the upper limit value of the operation frequency in the operation range in the standard specification region where the target evaporation temperature is −20 ° C. to −5 ° C. is set to 80 Hz. In addition, the upper limit value of the operating frequency in the operating range in the high temperature specification region where the target evaporation temperature is −5 ° C. or higher decreases as the target evaporation temperature increases. It is set as follows. As a result, operation exceeding the condensing capacity of the condenser 2 is prevented, and an abnormal increase in high pressure and an abnormal increase in operating current are prevented. As a result, it can be prevented that the protection control is activated, the compressor is stopped, and the refrigeration apparatus cannot be operated.

  That is, in this embodiment, in addition to the operation range in the standard specification region, for example, there is also an operation range in a high temperature specification region where the evaporation temperature is −5 ° C. or higher, and in the operation range in the high temperature specification region, The upper limit value of the compressor capacity (operating frequency, etc.) is set for each target evaporation temperature zone, and the rotation speed of the compressor 1 is controlled so as not to exceed the upper limit value of the compressor capacity for each set evaporation temperature zone. Like to do. Therefore, when the operation is performed in the high temperature specification region, the circulation amount of the refrigerant discharged from the compressor 1 is limited. Therefore, the operation in the high temperature specification region where the evaporation temperature is high can be performed with the same capacity condenser. An effect is obtained.

Next, the relationship between the target evaporation temperature (target suction pressure) set in the control device 101 and the upper limit value of the operating frequency (compressor capacity) of the compressor 1 will be described with reference to the diagram shown in FIG.
In FIG. 2, the horizontal axis indicates the target evaporation temperature, and the numerical value in () is the target suction pressure corresponding to each target evaporation temperature. The vertical axis represents the upper limit value of the operating frequency of the compressor 1 corresponding to the target evaporation temperature (target suction pressure).

  In this embodiment, as shown in FIG. 2, the target evaporation temperature is in the standard (refrigerated) specification region in the range of −20 ° C. to −5 ° C., and the target evaporation temperature is −5 ° C. or more (example in FIG. 2). Is set to −5 to 10 ° C.) is a high temperature specification region. That is, in the standard specification region where the target evaporation temperature is −20 ° C. to −5 ° C., the upper limit value of the compressor operating frequency is uniformly 80 Hz, and the compressor reaches the set target evaporation temperature at a frequency of 80 Hz or less. So that its frequency is controlled.

Further, in the high temperature specification region where the target evaporation temperature (ET) is −5 ° C. or higher, the upper limit value of the operating frequency of the compressor is set for each target evaporation temperature zone as follows.
In “-5 ° C <ET ≦ 0 ° C”, the upper limit of the operating frequency is 70 Hz.
In “0 ℃ <ET ≦ 5 ℃”, the upper limit of operation frequency is 60Hz.
In “5 ℃ <ET ≦ 10 ℃”, the upper limit of the operating frequency is 50Hz.
That is, in this embodiment, when the refrigeration apparatus is operated in a high temperature specification region where the target evaporation temperature exceeds −5 ° C., the target evaporation temperature is set so as not to exceed the condensing capacity of the condenser 2. Thus, an upper limit value is set for the operating frequency of the inverter compressor, and the compressor 1 is controlled so as not to exceed the upper limit value. Then, the higher the target evaporation temperature is set, the lower the upper limit value of the operation frequency of the inverter compressor 1 is set stepwise, and the refrigerant discharge amount from the compressor is appropriately set according to the target evaporation temperature. This makes it possible to operate in the high temperature specification area.
Instead of setting the target evaporation temperature (ET), the target suction pressure (PsU) may be set.

  Further, in this embodiment, as shown in FIG. 3, the refrigeration apparatus can be operated with the highest possible capacity even in the operation in the high temperature specification region. That is, the upper limit value of the operating frequency is changed according to the margin of the operating state of the refrigeration apparatus, and when the upper limit value is changed, the upper limit value capacity is not exceeded according to the changed upper limit value. The compressor is controlled. This will be described in detail below with reference to FIG.

  FIG. 3 is a diagram showing the relationship between the target evaporation temperature (target suction pressure) and the upper limit value of the operating frequency when the outside air temperature is taken into consideration. The refrigerating apparatus of the present embodiment includes the outside air temperature sensor 103, and the upper limit value of the compressor capacity that is changed according to the margin of the operating state of the refrigerating apparatus is the outside air temperature detected by the outside air temperature sensor 103. It is configured to be changed according to the situation.

  That is, when the outside air temperature is lower than a predetermined temperature and there is a margin in the condenser capacity (hereinafter also referred to as margin or margin), the upper limit value of the compressor capacity is corrected upward. Is. Here, the lower the outside air temperature, the greater the condensation capacity. Therefore, the upper limit value of the compressor capacity is corrected upward in a stepwise manner in accordance with the outside air temperature.

  Information on the outside air temperature detected by the outside air temperature sensor 103 shown in FIG. 1 is transmitted to the control device 101. The control device 101 determines a design outside air temperature as a reference. In the control device 101, when the detected outside air temperature is equal to or lower than a preset temperature, or the detected outside air temperature and the design outside air temperature. And the detected outside air temperature is lower than the designed outside air temperature by a predetermined temperature or more, it is determined that the condensing capacity of the condenser 2 has a margin (margin and margin).

  For example, when it is determined that the outside air temperature detected by the outside air temperature sensor 103 is lower than a preset temperature when operating in the high temperature specification region of the refrigeration apparatus and the condensation capacity has a margin, The upper limit value of the operating frequency in the high temperature specification region shown in FIG. 2 is set to a predetermined frequency as shown by the dotted line in FIG. 3 so that the condensation capability is not exceeded with respect to the condensation capability in consideration of the margin. Shifting upward (in the direction of increasing the upper limit frequency), the upper limit value of the operating frequency is changed.

  That is, when the target evaporation temperature is higher than −5 ° C. and lower than or equal to 0 ° C., the outside air temperature detected by the outside air temperature sensor 103 is lower by, for example, 5 ° C. or lower than the standard design outside air temperature, for example, 20 ° C. or lower. In this case, the upper limit value of the operating frequency is changed from 70 Hz to 75 Hz as shown in FIG. Therefore, the compressor 1 is frequency-controlled so as to reach the set target evaporation temperature at an operating frequency of 75 Hz or less.

  Similarly, when the detected outside air temperature is 20 ° C. and the target evaporation temperature is higher than 0 ° C. and lower than 5 ° C., the upper limit value of the operating frequency is 60 Hz to 65 Hz, and the target evaporation temperature is higher than 5 ° C. and lower than 10 ° C. The upper limit value of the operating frequency is changed from 60 Hz to 65 Hz, and the control device 101 controls the compressor 1.

  As described above, in this embodiment, when it is determined that the detected outside air temperature is lower than the preset set temperature and there is a margin in the condensation capacity during the operation in the high temperature specification region, the margin is set. Operation control is performed by changing the upper limit value of the operation frequency in the high temperature specification region to a value higher by a predetermined frequency so as not to exceed the condensing capacity with respect to the considered condensing capacity. Therefore, even when operating in the high-temperature specification area, the compressor can be operated at the highest operating frequency as long as the condensation capacity of the condenser is not exceeded. However, the effect of operating the refrigeration apparatus with high refrigeration capacity can be obtained.

  That is, according to the present embodiment, at least one of a discharge pressure sensor that detects a discharge pressure of the compressor, a discharge temperature sensor that detects a discharge side temperature of the compressor, and an outside air temperature sensor that detects an outside air temperature; A suction pressure sensor for detecting the suction pressure of the compressor, comprising an operating range in a standard specification region where the evaporation temperature is low, and an operating range in a high temperature specification region where the evaporation temperature is higher than the standard specification region, In the operating range in the high temperature specification region, the upper limit value of the compressor capacity is set according to the target evaporation temperature, and the upper limit value is changed according to the margin of the operating state of the refrigeration apparatus, and the upper limit value is When changed, the compressor is controlled so as not to exceed the upper limit capacity in accordance with the changed upper limit value, so that the evaporation temperature exceeds the operating range in the standard specification region. Even at a high temperature specification area to be evaporation temperature of the warm, while the protection control is inhibited from operating, it is possible to obtain a refrigerating apparatus capable of operating at higher condensation capacity.

  FIG. 4 shows another example of changing the upper limit value of the compressor capacity set according to the target evaporation temperature in accordance with the margin of the operating state of the refrigeration apparatus in the operation range in the high temperature specification region of the refrigeration apparatus. It is a figure which shows an example. That is, FIG. 4 explains Example 2 of the present invention, and is a diagram showing the relationship between the target evaporation temperature (target suction pressure) and the upper limit value of the operating frequency when the protection control condition of the refrigeration apparatus is taken into consideration. is there. The structure of the other refrigeration apparatus is the same as that shown in FIG.

  In the refrigeration apparatus I as shown in FIG. 1, the maximum discharge pressure and the maximum operating current that are the conditions for the protection control are usually determined. The protection control may be performed using the maximum discharge temperature on the compressor discharge side instead of the maximum discharge pressure or in addition to the maximum discharge pressure. The discharge pressure and the maximum operating current will be described as conditions for protection control of the refrigeration apparatus.

  In the second embodiment, the discharge pressure is detected by the discharge pressure sensor 104 shown in FIG. 1, and the operation current of the refrigeration apparatus detected by the operation current detection sensor provided on the control board of the control device 101 is detected. To do. Here, the operating current of the refrigeration apparatus may be the operating current of the compressor, or the operating current of the entire refrigeration apparatus including the operating current of the compressor. When the detected discharge pressure is lower than the maximum discharge pressure that is a condition for the protection control by a predetermined value or more, and when the detected current value is smaller than the maximum operation current that is the condition for the protection control by a predetermined value or more. It can be determined that there is a margin in the operating state of the refrigeration apparatus I. Therefore, in this case, it is possible to further increase the compressor capacity within a range that does not exceed the maximum discharge pressure and the maximum operating current that are the conditions for the protection control.

  Therefore, in this embodiment, the detected compressor discharge pressure and the detected operating current of the refrigeration apparatus are smaller than the maximum discharge pressure and the maximum operating current, which are the conditions for protection control of the refrigeration apparatus, by a predetermined value or more. When there is a margin in the operating state of the apparatus, the compression is changed in accordance with the margin of the operating state of the refrigeration apparatus, the value being lower than the predetermined value by the maximum discharge pressure and the maximum operating current that are the conditions for the protection control. Change as the upper limit of capacity. And the said compressor is controlled so that the upper limit value capacity | capacitance after the change may not be exceeded.

  A specific example will be described with reference to FIG. In FIG. 4, an alternate long and short dash line is a line indicating the upper limit value of the operating frequency determined based on the maximum discharge pressure and the maximum operating current, which are the conditions for the protection control. That is, when the operation is performed at a frequency higher than that indicated by the one-dot chain line, the protection control is activated and the refrigeration apparatus is stopped. Therefore, in the second embodiment shown in FIG. 4, during operation in the high temperature specification region, as shown by the dotted line, the discharge is lower than the predetermined value or higher than the maximum discharge pressure and maximum operating current at which the protection control indicated by the alternate long and short dash line operates. The operating frequency which becomes the pressure and the operating current is changed as the upper limit value, and the frequency is controlled so as to be the set target evaporation temperature within the operating frequency range below the dotted line. .

  That is, in this embodiment, at least one of the discharge pressure sensor or the discharge temperature sensor and an operating current detection sensor for detecting the operating current of the refrigeration apparatus, the compressor of the compressor detected by the discharge pressure sensor The maximum discharge pressure or maximum discharge temperature at which at least one of the discharge pressure or the discharge temperature detected by the discharge temperature sensor and the operating current of the refrigeration apparatus detected by the operating current detection sensor are the conditions for protection control of the refrigerator When the value is smaller than the maximum operating current by a predetermined value or more, it is determined that the operating state of the refrigeration apparatus has a margin. If it is determined that there is a margin, the discharge pressure or discharge temperature, which is a condition for the protection control of the refrigeration apparatus, and a value lower than the operating current by a predetermined value or more are changed according to the margin of the operating state of the refrigeration apparatus. The upper limit value of the compressor capacity is changed, and the compressor is controlled so as not to exceed the changed upper limit value capacity.

  The dotted line value indicating the upper limit value of the frequency in the high temperature specification region may be obtained in advance by experiment or calculation and used. In addition, since the alternate long and short dash line changes depending on the outside air temperature, it is preferable to change the dotted line accordingly.

  As a modification of the present embodiment, the following configuration may be used. That is, during the operation of the refrigeration apparatus, the detected value of the discharge pressure detected by the discharge pressure sensor 104 and the current value detected by the operating current detection sensor are the values of the protection control set in advance in the control device 101. The operating frequency of the compressor 1 may be controlled so as not to exceed values that are lower than a predetermined value by a predetermined maximum discharge pressure value and maximum operating current value.

  The higher the target evaporation temperature, the higher the discharge pressure from the compressor, and the higher the operating current of the refrigeration system.Therefore, in the high temperature specification area, the maximum discharge pressure value and the maximum operating current value, which are the conditions for protection control, are used as a reference. In this modified example, the compressor is controlled with an upper limit value that is smaller than the reference value of the protection control. According to this modification, it is not always necessary to set the upper limit value of the operating frequency indicated by the alternate long and short dash line or dotted line in FIG. 4, and the upper limit value of the operating frequency for each target evaporation temperature indicated by the solid line is not set. Also good.

  That is, the discharge pressure set value and the operating current set value that are lower than the maximum discharge pressure and the maximum operating current, which are protection control conditions, by a predetermined value or more are determined in advance. During operation in the high temperature specification region, the discharge pressure detected by the discharge pressure sensor 104 and the operation current detected by the operation current detection sensor are in the range below the discharge pressure set value and the operation current set value. To control the compressor. In this way, even when the target evaporation temperature is high, it is possible to operate the refrigeration apparatus that prevents the protection control from operating, and the refrigeration capacity in the high temperature specification region can be further improved.

  In the second embodiment, instead of the maximum discharge pressure or in addition to the maximum discharge pressure, the maximum discharge temperature on the compressor discharge side can be used in the same manner. An effect can be obtained.

  As described above, by controlling the operation of the compressor so that the protection control can be suppressed based on the maximum discharge pressure or the maximum discharge temperature, which is the condition for the protection control of the refrigeration apparatus, and the maximum operating current. In any operating environment, such as when operating in a high temperature specification region or when the outside air temperature is high, it is possible to suppress the operation of protection control of the refrigeration apparatus and operate with the maximum allowable condenser capacity.

  In each of the above-described embodiments, it is preferable to use R410A as the refrigerant used in the refrigeration apparatus that can be operated from the standard specification region to the high temperature specification region. If the refrigerant R410A is used, a refrigeration apparatus having high efficiency and high refrigerating capacity can be obtained even if the refrigerant is operated from the standard specification region to the high temperature specification region without changing the capacity of the condenser or the liquid receiver.

  According to each embodiment of the present invention, a refrigeration apparatus that has been separately manufactured separately from a refrigeration apparatus for refrigeration used in the standard specification area and a refrigeration apparatus for high temperature use used in the high temperature specification area. Using the same housing as the refrigeration unit operated in the standard specification area without increasing the capacity of the condenser or receiver, etc., from the standard specification area (refrigeration application) to the high temperature specification area (high temperature application) It is possible to manufacture a refrigeration apparatus that can be operated at a wide temperature range up to. In addition, to obtain a refrigeration system that can operate with higher condensing capacity while suppressing the activation of protection control even in a high temperature specification region where the evaporation temperature is higher than the operation range in the standard specification region. Can do.

I: Refrigeration equipment, II: Low-pressure side equipment,
1: compressor, 2: condenser, 3: supercooler, 4: evaporator, 5: receiver
6, 11: expansion valve, 7: solenoid valve,
8: sight glass, 9: dryer, 10: liquid injection piping,
12: Solenoid valve, 13: Accumulator,
14, 15: Blower fan, 16: External heater,
17, 18: Piping connection part,
101: Control device, 102: Suction pressure sensor, 103: Outside air temperature sensor,
104: Discharge pressure sensor, 105: Discharge temperature sensor.

Claims (11)

In a refrigeration apparatus comprising a compressor and a condenser capable of controlling capacity,
At least one of a discharge pressure sensor for detecting a discharge pressure of the compressor, a discharge temperature sensor for detecting a discharge side temperature of the compressor, and an outside air temperature sensor for detecting an outside air temperature;
A suction pressure sensor for detecting the suction pressure of the compressor;
It has an operating range in the standard specification area where the evaporation temperature is low and an operating range in a high temperature specification area where the evaporation temperature is higher than the standard specification area.
In the operating range in the high temperature specification region, while setting the upper limit value of the compressor capacity according to the target evaporation temperature,
The upper limit value is changed according to a margin of the operating state of the refrigeration apparatus, and when the upper limit value is changed, the compressor controls the upper limit value capacity so as not to exceed the changed upper limit value. The refrigeration apparatus characterized by being made.   The refrigerating apparatus according to claim 1, wherein the refrigerating apparatus is configured to be connected to a low-pressure side device having an expansion valve and an evaporator by a refrigerant pipe.   3. The refrigeration apparatus according to claim 1, wherein the compressor whose capacity can be controlled is an inverter compressor having a variable drive frequency.   3. The refrigeration apparatus according to claim 1, wherein the capacity-controllable compressor is composed of a plurality of compressors, and the capacity is controlled by controlling the number of drives. .   5. The refrigeration apparatus according to claim 1, further comprising at least the outside air temperature sensor, wherein the upper limit value of the compressor capacity that is changed according to a margin of an operating state of the refrigeration apparatus is the outside air temperature sensor. The refrigeration apparatus is changed according to the outside air temperature detected in step (b).   6. The refrigeration apparatus according to claim 5, wherein the upper limit value of the compressor capacity is corrected upward when the outside air temperature is lower than a set value and there is a margin in the condenser capacity.   7. The refrigeration apparatus according to claim 6, wherein the upper limit value of the compressor capacity is corrected upward stepwise in accordance with the outside air temperature as the outside air temperature is lower.   The refrigeration apparatus according to any one of claims 1 to 4, comprising at least one of the discharge pressure sensor or the discharge temperature sensor, and an operation current detection sensor for detecting an operation current of the refrigeration apparatus, wherein the discharge pressure At least one of the discharge pressure of the compressor detected by the sensor or the discharge temperature detected by the discharge temperature sensor, and the operating current of the refrigeration apparatus detected by the operating current detection sensor are the conditions for the protection control of the refrigerator. When the maximum discharge pressure or maximum discharge temperature and the maximum operating current are less than a predetermined value and there is a margin in the operation state of the refrigeration apparatus, the discharge pressure or discharge side temperature and operation that are the conditions for protection control of the refrigeration apparatus A value lower than the current by a predetermined value or more is changed as the upper limit value of the compressor capacity that is changed according to the margin of the operating state of the refrigeration system. Refrigeration system, characterized in that said compressor is controlled so as not to exceed the value capacitor.   The refrigeration apparatus according to any one of claims 1 to 8, wherein the operation range in the standard specification region where the evaporation temperature is low is an operation range where the evaporation temperature is -20 ° C to -5 ° C, and the high temperature specification region where the evaporation temperature is high. The refrigeration apparatus is characterized in that the operating range is an operating range in an evaporation temperature range of -5 ° C to 10 ° C.   The refrigeration apparatus according to any one of claims 1 to 9, wherein the refrigerant used is R410A. The refrigeration apparatus according to any one of claims 1 to 10, further comprising: a liquid receiver provided on the downstream side of the condenser; and a subcooler provided on the downstream side of the liquid receiver. refrigeration equipment which is characterized.

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