KR0153407B1 - Refrigeration apparatus - Google Patents

Abstract

The present invention relates to a refrigerating device using a mixture of a refrigerant and a refrigerant adjusting means for adjusting a ratio between refrigerants so as to adjust a freezing capacity during a freezing operation, wherein the freezing device rotates a compressor to obtain a required freezing capacity. The speed is controlled and the refrigerant controller adjusts the ratio between the refrigerants when the rotational speed is out of the lower set value or the upper set value.

Description

Freezer

1 shows a prior art refrigeration apparatus using a single refrigerant.

2 is a view showing a refrigeration apparatus according to an embodiment of the present invention.

3 is a characteristic diagram showing the correlation between the mixing ratio of the refrigerant and the freezing capacity.

4 shows controlled room temperature during the heating process.

5 shows the correlation between the rotational speed and the freezing capacity.

FIG. 6 shows the freezing device of FIG. 2 with a variant in which capillaries are disposed around the tank.

7 shows the refrigeration apparatus of FIG. 2 with a variant in which a pressure reducer is arranged around the tank.

8 shows the refrigeration apparatus of FIG. 2 with a modification including a refrigerant heater comprising a regulator.

FIG. 9 is a view of the refrigeration apparatus of FIG. 2 having a modification in which a tank is installed in a passage through which gaseous refrigerant passes.

FIG. 10 shows the refrigeration apparatus of FIG. 2 with a variant in which a tank is disposed in a passage through which gaseous and liquid refrigerants respectively pass.

11 is a view showing a refrigerating device using the discharge compressor according to the present invention.

12 is a characteristic diagram of the apparatus shown in FIG.

13 shows the main part of a discharge compressor according to the invention;

14 is a view showing the operating state of the compressor of FIG.

FIG. 15 is a view showing an operating state of the compressor of FIG.

* Explanation of symbols for main parts of the drawings

1 compressor 3 suction cup

5: 4 valve 7: Internal heat exchanger

9: tank 11: pressure reducer

13: external heat exchanger 17: internal fan

19: refrigerant heater 21: heat transfer tube

23: control valve 27: regulator

31: refrigerant temperature sensor 33: external fan

The present invention relates to a refrigeration apparatus using a mixture of refrigerants, and more particularly to adjusting the mixing ratio of the refrigerant to control the refrigeration capacity of the apparatus.

1 shows a prior art refrigeration apparatus having a compressor 101, an internal heat exchanger 103, a pressure reducer 105 and an external heat exchanger 107. During the refrigeration operation, the internal heat exchanger 103 operates as an evaporator and the external heat exchanger 107 operates as a condenser. The refrigerant discharged from the compressor 101 flows through the external heat exchanger 107, the pressure reducer 105, and the internal heat exchanger 103 along the direction of the dashed arrow in FIG. 1. The refrigerant passed through the above process is returned to the compressor 101.

The refrigeration apparatus of FIG. 1 is a heat pump type and includes a four-way valve 109. In order to perform the heating operation, the four-pipe valve 109 must be switched so that the internal heat exchanger 103 operates as a condenser and the external heat exchanger 107 operates as an evaporator. The refrigerant discharged from the compressor 101 flows through the internal heat exchanger 103, the pressure reducer 105, and the external heat exchanger 107 along the direction of the solid arrow in FIG. 1. The refrigerant passed through the above process is returned to the compressor 101.

The internal and external heat exchangers 103 and 107 operate as evaporators or condensers, respectively, in accordance with refrigeration and heating operations.

The freezing capacity of the refrigerating device is determined according to the capacity of the compressor 101. In order to increase the freezing capacity of the refrigeration unit, the compressor must be rotated at a very high speed or replaced with a larger one.

Rotating the compressor 101 at a very high rotational speed generates vibration, friction and noise and reduces durability. If the compressor 101 is replaced with a larger one, the overall size and weight of the refrigerating device is increased.

As the refrigerant of the refrigerating device, a mixture of a high boiling point and a low one may be used. A high boiling point refrigerant has a higher boiling point and condensation temperature under the same condensation pressure than a low boiling point refrigerant. In other words, the refrigerant having a higher boiling point can send higher temperature air into the room. Even when the discharge pressure of the compressor 101 is not too high, the high boiling point refrigerant provides a high condensation temperature to blow hot air into the room, thereby improving the heating capacity of the refrigerating device.

However, high boiling point refrigerants have one drawback. When the temperature of the ambient air is low, the compressor 101 rotates at a high rotational speed so that the circulation amount of the refrigerant increases to increase the heating capacity. In this case, the specific volume of the high boiling point refrigerant evaporating in the evaporator (external heat exchanger 107) becomes so large that the pressure loss increases in the suction pipe between the evaporator 107 and the compressor 101. Therefore, the suction amount of the compressor 101 does not increase even if the rotation speed of the compressor 101 increases.

On the other hand, the specific volume of the low boiling point refrigerant evaporating in the evaporator is small. Therefore, the circulation amount of the refrigerant having a low boiling point is large by replacing the compressor 101 as described above. As a result, the efficiency of the heating operation increases. When the ambient temperature is low to reduce the heating capacity, it is advisable to increase the ratio of low boiling refrigerant to high boiling refrigerant. However, if the low boiling refrigerant is released at high temperature, the discharge pressure of the compressor 101 exceeds the design allowable pressure value, so that the low boiling refrigerant shows a higher condensation pressure under the same condensation temperature.

An object of the present invention is to provide a refrigeration apparatus that effectively uses the characteristics of the refrigerant mixture to increase the performance of the refrigeration process without using a large-capacity compressor.

In order to achieve the above object, the present invention includes a control device for adjusting the mixing ratio between the refrigerant to adjust the mixture of the refrigerant and the freezing capacity during the refrigeration process.

The apparatus includes a compressor 101 whose rotation speed is adjusted to provide the desired refrigeration capacity. When the rotational speed of the compressor falls below the lower set point or exceeds the upper set point, the refrigerant control device adjusts the ratio between the refrigerants.

In this way the compressor operates efficiently from minimum to maximum capacity.

When the compressor is operated at minimum capacity, the refrigerant regulator increases the ratio of high boiling refrigerant to low boiling refrigerant to increase the specific volume of the refrigerant mixture. As a result, the capacity of the compressor is reduced.

When the compressor is operated at full capacity, the refrigerant regulator increases the ratio of low boiling refrigerant to high boiling refrigerant to reduce the specific volume of the refrigerant mixture. As a result, the capacity of the compressor is increased without employing a large capacity compressor.

The above and other objects, features and advantages of the present invention will be described in more detail as specific and preferred embodiments shown in the drawings.

An embodiment of the refrigeration apparatus according to the present invention will be described in detail with reference to FIGS. 2 to 9.

The refrigeration apparatus of FIG. 2 is used as an air pump type air conditioner, and uses a high boiling point refrigerant and a low boiling point refrigerant. This refrigeration unit has a compressor having a suction cup (3), a four-pipe valve (5), an internal heat exchanger (7), a refrigerant control tank (9), a pressure reducer (11) and an external heat exchanger (13). It includes 1). These components are connected to each other via the refrigerant pipe (15).

3 shows a correlation between the mixing ratio of the refrigerant and the freezing capacity. The standard refrigeration capacity 100% is obtained when the ratio of the low boiling refrigerant to the high boiling refrigerant is X. The freezing capacity increases when the ratio of the low boiling refrigerant to the high boiling refrigerant increases in the zone Z direction. On the other hand, the freezing capacity decreases when the ratio of the low boiling point refrigerant to the high boiling point refrigerant decreases in the region Y direction. The refrigerant mixture according to the embodiment of the present invention is not an azeotropic mixture.

5 shows a correlation between the rotational speed of the compressor 1 and the refrigerating capacity. Since the target room temperature and the actual room temperature are different, the compressor 1 is operated in the rotational speed range of about 10 to 120 Hz. The compressor 1 receives the gaseous refrigerant mixture from the suction cup 3 and discharges the high temperature and high pressure refrigerant mixture gas.

The four-pass valve 5 switches the flow of the refrigerant mixture from the compressor 1 to the internal heat exchanger 7 or the external heat exchanger 13.

The internal heat exchanger 7 operates as an evaporator during the freezing operation and as a condenser during the heating operation.

When the internal heat exchanger 7 operates as an evaporator, it receives the low temperature, low pressure refrigerant mixture gas in the form of a mist from the pressure reducer 11. An internal fan 17 allows the refrigerant in the internal heat exchanger 7 to absorb and evaporate the latent heat of air passing through the fins of the internal heat exchanger 7 to cool the air. Send air to. The inner fan 17 sends the frozen air to the room.

When the internal heat exchanger 7 operates as a condenser, it receives high temperature, high pressure refrigerant mixture gas from the compressor 1. An internal fan 17 directs air to the internal heat exchanger 7 so that air absorbs the latent heat of the refrigerant mixture passing through the internal heat exchanger 7. As a result, the refrigerant mixture becomes fogged, and at the same time, heated air is sent to the room by the internal fan 17.

The tank 9 is provided in the passage 15a to allow the liquid refrigerant mixture to pass between the internal heat exchanger 7 and the pressure reducer 11. The refrigerant mixture flows into the tank 9 until the tank 9 is full. The refrigerant in the tank 9 is heated by the refrigerant heater 19.

The refrigerant heater 19 has a heat transfer tube 21 for passing the refrigerant mixture. The heat transfer tube 21 is wound around the tank 9. One end of the heat transfer tube 21 is connected to the outlet of the compressor 1 through the control valve 23. The other end of the heat transfer tube 21 is connected to the refrigerant tube 15, that is, the liquid passage 15a between the internal heat exchanger 7 and the pressure reducer 11. The heat exchange tube 21 passes a high temperature, high pressure refrigerant mixture gas from the compressor 1.

The controller 27 receives a signal from a load sensor S of an air conditioner such as a temperature sensor to adjust the operating speed of the compressor 1. The regulator 27 also adjusts the opening degree of the control valve 23 according to the correlation between the load of the air conditioner and the rotational speed of the compressor 1. The regulator 27 adjusts the temperature of the tank 9 between the heating temperature at which the low boiling refrigerant evaporates and the heating temperature at which the high boiling refrigerant evaporates. That is, the amount of the refrigerant mixture stored in the tank 9 is adjusted to control the ratio between the low boiling point refrigerant and the high boiling point refrigerant circulated in the freezer.

8 shows a variation of the embodiment of FIG. A refrigerant heater 30 corresponding to the refrigerant heater 19 is installed in the tank 9. The refrigerant heater 30 is regulated by the regulator 29. This modification can precisely control the heating temperature of the refrigerant mixture and provide the required ratio between the high boiling point refrigerant and the low boiling point refrigerant at the beginning of operation of the refrigerating device.

Referring back to FIG. 2, the pressure reducer 11 makes the refrigerant mixture into a low temperature, low pressure mist form. The pressure reducer 11 is operated in accordance with an indication signal from the refrigerant temperature sensor 31 installed in the suction system of the compressor 1. In this case, the pressure reducer 11 adjusts the flow rate of the refrigerant mixture according to operating conditions such as thermal load.

The external heat exchanger 13 operates as an evaporator during the heating operation and as a condenser during the freezing operation. When the external heat exchanger 13 operates as an evaporator, it receives a refrigerant mixture in a fog state. This mist evaporates by the heat of the air passing through the fins of the external heat exchanger (13). Air is sent outward through the outer fan 33.

The external heat exchanger 13 contains a high temperature, high pressure refrigerant mixture gas when operating as a condenser. The external fan 33 sends air to the external heat exchanger 13 and the air absorbs the latent heat of the refrigerant mixture. As a result, the refrigerant mixture condenses in the liquid state and the air which absorbs the latent heat is sent outward by the external fan 33.

During the heating operation in which the internal heat exchanger 7 operates as a condenser and the external heat exchanger 13 operates as an evaporator, the refrigerant mixture discharged from the compressor 1 is transferred to the internal heat exchanger 7, the pressure reducer 11 and the external. The heat exchanger 13 then flows back to the compressor 1. At the beginning of the heating operation, the ratio of the low boiling point refrigerant and the high boiling point refrigerant is the initial value when the refrigerant is first sealed in the refrigerating device.

If the difference between the target room temperature TS and the actual room temperature in FIG. 4 during the heating operation becomes large, the regulator 27 signals the control valve 23 to open completely. As a result, the high temperature, high pressure refrigerant gas from the compressor 1 flows through the heat transfer tube 21 to heat the refrigerant mixture stored in the tank 9.

Due to the heating and the internal pressure of the tank 9, the low boiling point refrigerant in the tank 9 vaporizes and flows into the refrigerant pipe 15. As a result, the ratio of the high boiling point refrigerant to the low boiling point refrigerant in the tank 9 increases. On the other hand, in the refrigerant mixture circulating in the refrigerating device, the ratio of the low boiling point refrigerant to the high boiling point refrigerant increases in the zone Z (FIGS. 3 to 4), thereby increasing the heating capacity.

The air passing through the fins of the internal heat exchanger 7, which acts as a condenser, is then efficiently heated and supplied to the room as hot air.

The refrigerant mixture flowing through the external heat exchanger 7 acting as an evaporator absorbs the latent heat of air flowing through the fins of the external heat exchanger 7. This heat causes the refrigerant mixture in the external heat exchanger 13 to change from fog to gas. The ratio of low boiling refrigerant to high boiling refrigerant in this gas is large so that the specific volume of the vaporized refrigerant mixture is reduced. That is, the amount of the refrigerant mixture with respect to the discharge of the compressor 1 is increased so as to quickly raise the room temperature.

As the actual room temperature approaches the target temperature TS, the temperature difference becomes smaller and the rotational speed of the compressor 1 drops. In response to the rotational speed of the compressor 1, the control valve 23 limits the flow rate of the hot refrigerant mixture. As a result, the ratio between the high boiling point refrigerant and the low boiling point refrigerant moves from the region X to the region Y and the heating capacity is reduced.

During refrigeration operation, the internal heat exchanger 7 operates as an evaporator and the external heat exchanger 13 operates as a condenser. The compressor 1 sucks and compresses the refrigerant mixture and discharges the high temperature and high pressure refrigerant mixture gas to the condenser, that is, the external heat exchanger 13. The latent heat of the refrigerant mixture is absorbed by the air passing through the fins of the external heat exchanger 13 to liquefy the refrigerant mixture.

The refrigerant mixture in the liquid state flows into the pressure reducer 11 and expands rapidly to become a low temperature, low pressure fog state. Fog flows into the evaporator, i.e., the internal heat exchanger 7, in which the refrigerant absorbs heat from the air flowing through the fins of the internal heat exchanger (7). As a result, the fogged refrigerant is vaporized and the air is cooled. The cooled air is sent to the room and the vaporized refrigerant enters the compressor (1). The process is repeated during the freezing operation.

During refrigeration operation, the compressor 1 is operated in the range of 30 to 100 Hz to provide a high refrigeration capacity as in FIG. If the difference between the target temperature TS and the actual room temperature is large, the regulator 27 sends a signal such that the regulating valve 23 is fully opened so that the heater 19 heats the tank 9. In the tank 9, the ratio of the high boiling refrigerant to the low boiling refrigerant increases. On the other hand, the ratio of the low boiling point refrigerant to the high boiling point refrigerant in the actually circulating refrigerant mixture increases to move to the zone Z.

As the temperature difference decreases, the ratio between the high boiling point refrigerant and the low boiling point refrigerant moves to the region X in response to the rotational speed of the compressor 1 and then to the region Y to reduce the capacity of the compressor 1. As shown in FIG. 5, the present invention operates the refrigerating device at the refrigerant ratios A, B, C and D to provide a larger capacity area Q2 than the capacity area Q1 in the prior art. In this way, the compressor 1 is operated efficiently so that power consumption, noise, vibration and wear are reduced during refrigeration and heating operations.

6 shows a modification based on the embodiment of FIG. Capillaries 35 with various shrinkage rates are installed around the tank 9 to optimize the internal pressure of the tank 9 for low boiling refrigerant. The passage 39 extends from the top of the tank 9 into the refrigeration circulation system. This method accurately adjusts the ratio between the high boiling point refrigerant and the low boiling point refrigerant in the tank 9 and improves the controllability of the freezing operation.

FIG. 7 shows another variant based on the embodiment of FIG. 2. The pressure reducer 11 is provided at the front and rear ends of the tank 9. The regulator 42 optimizes the flow rate of the refrigerant mixture by adjusting the pressure reducer in response to the load of the air conditioner, the refrigerant temperature or the rotational speed of the compressor 1. The combination of the pressure reducer 11 for controlling the flow rate of the refrigerant mixture entering and exiting the tank 9 and the refrigerant heater 19 for heating the refrigerant mixture in the tank 9 efficiently vaporizes the low boiling refrigerant. In addition, the amount of the liquid refrigerant in the tank 9 is precisely controlled, and the ratio between the high boiling point refrigerant and the low boiling point refrigerant which is actually circulated in the refrigerating device according to the operating conditions of the compressor 1 is optimized.

9 shows another variation based on the embodiment of FIG. The tank 9 is provided in a passage 15b located on the inlet side of the compressor 1 to allow the refrigerant mixture in a gaseous state to pass therethrough.

The heat transfer tube 41 is wound around the tank 9. One end of the heat transfer tube 41 is connected to the inlet side of the compressor 1, and the other end thereof is a bypass 43 between the first control valve 45 and the second control valve 47. Is connected to. The end of the heat transfer pipe 41 connected to the inlet side of the compressor 1 may be connected to a gas injection pipe extending from the compressor 1.

The regulator 46 adjusts the opening degree of the first and second regulating valves in response to the rotational speed of the compressor 1 or the air conditioner load. One end of the bypass 43 is connected to the outlet of the compressor 1, and the other end is connected to the connecting tube between the internal heat exchanger 7 and the external heat exchanger 13.

The oil return pipe 49 returns lubricant from the compressor 1 to the tank 9 when all the refrigerant in the tank 9 is vaporized.

During the heating operation, the refrigerant mixture discharged from the compressor 1 flows through the internal heat exchanger 7, the pressure reducer 11 and the external heat exchanger 13 along the solid arrow direction and returns to the compressor 1.

In the heating operation, a second control valve may be opened according to the rotational speed of the compressor 1 or the load of the air conditioner to cool the tank 9 with the refrigerant gas flowing through the heat transfer pipe 41 and the first control valve. Is closed. As a result, the high boiling point refrigerant in the tank 9 aggregates in the liquid state, thereby increasing the ratio of the low boiling point refrigerant to the high boiling point refrigerant in the refrigerant mixture which substantially circulates in the freezer.

When the first regulating valve is open and the second regulating valve is closed, the high temperature, high pressure refrigerant gas from the compressor 1 flows through the heat transfer pipe 41 to heat the tank 9. As a result, the liquid refrigerant in the tank 9 vaporizes, and thus returns to the ratio between the high boiling point refrigerant and the low boiling point refrigerant, such as when the refrigerant is first sealed in the apparatus.

In this way, by adjusting the opening degree of the first control valve and the second control valve, the ratio between the high boiling point refrigerant and the low boiling point refrigerant can be adjusted to an optional value.

10 shows another variation. This combines the schemes of FIGS. 8 and 9. According to the method of FIG. 10, the ratio between the high boiling point refrigerant and the low boiling point refrigerant can be adjusted in a wide range according to the operating conditions.

11 shows a refrigerating device according to the invention using a discharge compressor 55.

The compressor 55 has a plurality of cylinders. The cylinder chambers adjacent to the cylinder of the compressor 55 are connected to each other via the passage 51. The passage 51 is closed by the switchgear 53 and 54 in the normal operation state and is opened when the capacity of the compressor 1 decreases. Corresponding to the opening and closing of the opening and closing devices 53 and 54, the tank 9 operates as a refrigerant regulator for controlling the ratio between the high boiling point refrigerant and the low boiling point refrigerant circulating in the refrigerating device.

The tank 9 is provided in the passage 15a so that the liquid refrigerant mixture in the liquid state passes between the internal heat exchanger 7 and the pressure reducer 11. The liquid refrigerant flows into the tank 9 until the tank 9 is filled. The refrigerant mixture in the tank 9 is heated by the refrigerant heater 19.

The refrigerant heater 19 includes a heat transfer tube 21 for passing the refrigerant mixture. The heat transfer tube 21 is wound around the tank 9. One end of the heat transfer tube 21 is connected to the outlet of the compressor 55 via a control valve 23, the other end of which is a refrigerant tube 15 between the internal heat exchanger 7 and the pressure reducer 11. Is connected to the passage 15a. The high temperature, high pressure refrigerant gas from the compressor 55 flows through the heat transfer pipe 55.

The regulator 27 receives the opening and closing signal from the opening and closing device 53 and 54 and adjusts the opening degree of the control valve 23 according to the signal. The controller 27 adjusts the temperature of the tank 9 between the heating temperature at which the low boiling point refrigerant is vaporized and the heating temperature at which the high boiling point refrigerant is vaporized. That is, the amount of the refrigerant mixture in the tank 9 is adjusted to adjust the ratio between the high boiling point refrigerant and the low boiling point refrigerant circulating in the freezer.

Figure 12 compares the prior art with the present invention. The dose range Q2 with the present invention is broader than the dose range Q1 in the prior art. This wide capacity range in the present invention is obtained by the refrigerant mixture and the discharge compressor.

13 to 15 show a discharge type compressor 59 applicable to the refrigerating device of the present invention.

The capacity of the compressor 59 is mechanically adjusted. Combining the mechanical capacity control of the compressor 59 with the ratio control between the refrigerants can widen the adjustable capacity range of the refrigeration unit.

The compressor 59 has an accessory bearing 61 for forming the cylinder chamber 60. The accessory bearing 61 has a discharge port 63. When the cylinder chamber 60 receives and compresses the refrigerant mixture, part of the refrigerant mixture is bypassed to the lower pressure through the discharge port 63, so that the capacity of the compressor 59 is reduced.

The compressor (59) includes a frame (65), a cylinder (67), a shaft (69), a suction cup (71), a check valve (73), a discharge pipe (75), and a roller ( 77).

In FIG. 14, the check valve 73 is located between the discharge port 63 and the discharge tube 75. When the pressure at the discharge port 63 is greater than the pressure at the discharge tube 75, that is, when valve A is opened and valve B is closed so that the discharge tube 75 is connected to the low pressure side, the refrigerant mixture is drawn from the compression chamber to the low pressure side. Passed, thus reducing the amount of refrigerant mixture to be compressed. When valve A is closed and valve B is open, the discharge tube 75 is connected to the high pressure side. Due to the high pressure, the check valve 73 is closed so that the refrigerant is not bypassed. Thus, the compressor 59 provides a normal capacity depending on the volume of the cylinder.

15 shows the operation of the discharge port 63. The roller 77 rotates eccentrically. One end face of the roller 77 opens the discharge port 63 at a particular rotation angle. When the end face of the roller 77 deviates from the discharge port 63, the refrigerant mixture is discharged to the low pressure side. When the end face of the roller 77 closes the discharge port 63, the refrigerant mixture is compressed. The discharge port 63 is not located in the compression chamber during the compression cycle so that the maximum volume tolerance is maintained for the compressor 59 to operate efficiently.

Although the present invention has been described with reference to a heat pump type refrigeration apparatus for performing a freezing and heating operation, it is also applicable to a refrigerator.

In conclusion, the refrigerating device of the present invention controls the mixing ratio between the constituent refrigerants of the refrigerant mixture, thereby widening the minimum and maximum ranges of the heating and freezing capacity. The present invention effectively utilizes a refrigerant mixture in operating a compressor in an efficient operating area to suppress noise, friction and vibration and to extend durability.

It will be apparent to those skilled in the art that various modifications may be made without departing from the scope of the present invention.

Claims (5)

A refrigeration apparatus having a refrigerant circuit in which a compressor, a condenser, a pressure reducing device, and an evaporator are connected in sequence, and a refrigerant mixed with refrigerants having different boiling points as a refrigerant circulating through the refrigerant circuit, wherein the refrigerant circuit or part of the refrigerant circuit is used. A tank installed bypassed to accumulate mixed refrigerant; A refrigerant heater installed in the tank; A heat transfer tube for supplying a mixed refrigerant of high or low temperature branched from a refrigerant circuit to the refrigerant heater; And a refrigerant control device having a control valve installed in the heat transfer pipe, wherein the refrigerant control device heats or cools the mixed refrigerant during a freezing operation to change the freezing capacity by changing a component ratio of the mixed refrigerant. Refrigeration unit. The refrigerant circuit according to claim 1, wherein the rotational speed of the compressor is controlled to obtain a desired refrigeration capacity under a mixed refrigerant of a predetermined component ratio, and the refrigerant control device is configured to provide A refrigeration apparatus characterized by expanding the refrigerating capacity below the minimum freezing capacity or the maximum freezing capacity of the compressor by controlling to change the component ratio of the mixed refrigerant. The multicylinder compressor according to claim 1, wherein the compressor has a passage communicating with the cylinder chambers of adjacent cylinders with each other, and an opening and closing mechanism for closing the passage during normal operation and opening the passage when the capacity of the compressor is lowered. And a refrigerant control device to change the component ratio of the mixed refrigerant in the refrigerant circuit in response to the 'open' or 'close' of the opening / closing mechanism. The refrigeration apparatus according to claim 1, wherein the mixed refrigerant is an azeotropic mixed refrigerant consisting of a low boiling point refrigerant and a high boiling point refrigerant. 3. The refrigerating device according to claim 2, wherein the compressor has a compression capacity varying mechanism for reducing the freezing capacity by bypassing a portion of the refrigerant to low compression during the compression stroke.