JPH07234027A - Cascade refrigerator - Google Patents

Abstract

PURPOSE:To provide a cascade refrigerator in which a pull-down time of a low temperature side refrigerant circuit can be shortened without increasing refrigerating capacity of a high temperature side refrigerant circuit. CONSTITUTION:A compressor 32, a condenser 34, an expansion valve 37 and an evaporator 41 are sequentially annularly connected to form a high temperature side refrigerant circuit 51. A compressor 2, a condenser 21, an expansion valve 7, an evaporator 8 and an accumulator 9 are sequentially annularly connected to form a low temperature side refrigerant circuit 52. The evaporator 41 and the condenser 21 are provided in a heat exchanging manner to form a cascade condenser 4. A discharge side tube 3 of the compressor 2 of the circuit 52 is provided in a heat exchanging manner with the accumulator 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a freezer or the like for cooling the inside of a refrigerator to an extremely low temperature or an ultralow temperature, and is provided with a high temperature side refrigerant circuit and a low temperature side refrigerant circuit, and is provided with an evaporator of the high temperature side refrigerant circuit. The present invention relates to a multi-source refrigeration system configured to condense the refrigerant in a low temperature side refrigerant circuit.

[0002]

2. Description of the Related Art Conventionally, for a freezer or the like for cooling the inside to an extremely low temperature or an ultra-low temperature, a multi-source refrigerating device as shown as a dual refrigerating device in, for example, Japanese Utility Model Publication No. 5-10955 (F25B7 / 00) is used. Has been. In such a multi-source refrigeration system, the low temperature side refrigerant circuit and the high temperature side refrigerant circuit are connected by a cascade condenser, and the inside of the refrigerator cooled by the evaporator of the low temperature side refrigerant circuit is kept at an extremely low temperature such as −60 ° C. to −80 ° C. It is cooling.

In the high temperature side refrigerant circuit, a refrigerant having a relatively high boiling point temperature such as Freon R22 (boiling point temperature -40.8 ° C.) is enclosed, and in the low temperature side refrigerant circuit, Freon R23 (boiling point). A refrigerant having a low boiling point such as a temperature of −82.03 ° C.) is enclosed, and an evaporator of the high temperature side refrigerant circuit and a condenser of the low temperature side refrigerant circuit are provided in a heat exchange manner to form a cascade condenser. The high pressure refrigerant in the low temperature side refrigerant circuit is condensed by the evaporator.

The conventional multi-source refrigeration system 100 will be described below with reference to FIG. 4. The multi-source refrigeration system 100 comprises, for example, a high temperature side refrigerant circuit 101 and a low temperature side refrigerant circuit 102. The discharge side pipe 3 of the compressor 2 of the low temperature side refrigerant circuit 102 is connected to the closed vessel condenser 21, and the outlet side pipe 14 of the condenser 21 is connected to the subcooler 5. Further, the outlet side pipe 6 of the subcooler 5 is connected to an evaporator 8 via an expansion valve 7 which is a pressure reducing device. The expansion valve 7 detects the temperature of the outlet side pipe 15 of the evaporator 8, and the throttle amount is automatically controlled so that this temperature becomes constant.

The outlet side pipe 15 of the evaporator 8 is connected to an accumulator 19, and the accumulator 19 is connected to the suction side pipe 10 of the compressor 2 to form an annular low temperature side refrigerant circuit 102. In the figure, Fa is a blower for cooling the inside of the refrigerator, 12 is a high pressure switch, and A is an oil separator. An expansion tank 16 is connected between the discharge side pipe 3 of the compressor 2 and the outlet side pipe 15 of the evaporator 8 via an opening / closing valve B. Incidentally, C is a blower for cooling the compressor 2.

On the other hand, the compressor 32 of the high temperature side refrigerant circuit 101
A condenser 34 is connected to the discharge side pipe 33 of the condenser 3
4 is connected to the liquid receiver 35. And the liquid receiver 35
After passing through the expansion valve 37, the outlet side pipe 36 becomes an evaporator 41, passes through the inside of the subcooler 5 of the low temperature side refrigerant circuit 102, and further passes through the inside of the condenser 21 of the low temperature side refrigerant circuit 102 in a heat exchange manner. Connected to the accumulator 38. The evaporator 41 of the high temperature side refrigerant circuit 101 and the condenser 21 of the low temperature side refrigerant circuit 102 constitute the cascade condenser 4. The accumulator 38 is connected to the suction side pipe 39 of the compressor 32 to form an annular high temperature side refrigerant circuit 101. The expansion valve 37 detects the temperature of the outlet side pipe 36 of the evaporator 41 and adjusts the opening degree. Further, 40 is a high pressure switch, and Fb is a blower for air-cooling the condenser 34.

Next, the operation will be described. High temperature side refrigerant circuit 10
It is assumed that, for example, a predetermined amount of the R22 refrigerant is enclosed in the inside of 1, and a predetermined amount of the R23 refrigerant is enclosed in the low temperature side refrigerant circuit 102. When the multi-source refrigeration system 100 is operated by a control device (not shown), for example, the high temperature side refrigerant circuit 101 is first operated, and thereby the temperature of the cascade condenser 4 is lowered to a predetermined temperature, and then the low temperature side refrigerant circuit 102 is operated. I shall. High temperature side refrigerant circuit 101
The compressor 32 is started and the high-temperature and high-pressure gas refrigerant is supplied to the pipe 33.
Then, the refrigerant flows from the pipe 33 into the condenser 34, where it is air-cooled by the blower Fb, condensed and liquefied, and then flows into the liquid receiver 35.

Then, the liquid receiver 35 separates gas and liquid, the liquid refrigerant is decompressed by the expansion valve 37, flows into the evaporator 41, and first performs a cooling action in the subcooler 5 while evaporating.
The refrigerant discharged from the subcooler 5 flows into the cascade condenser 4, evaporates there to exert a cooling effect, and then is sucked into the compressor 32 through the pipe 39 through the accumulator 38.

When the temperature of the cascade condenser 4 is lowered to a predetermined temperature by the operation of the high temperature side refrigerant circuit 101, the control device starts the operation of the low temperature side refrigerant circuit 102. Then, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the cascade condenser 4 formed by the condenser 21 from the pipe 3. Cascade capacitor 4
Since the inside is cooled by the evaporator 41 of the high temperature side refrigerant circuit 101 as described above, the inflowing high temperature gas refrigerant is cooled there and condensed and liquefied. Then, the refrigerant flows into the subcooler 5 via the pipe 14. Since the inside of the subcooler 5 is also cooled by the evaporator 41 of the high temperature side refrigerant circuit 101 as described above, the refrigerant is further cooled, condensed and liquefied, and flows out to the pipe 6.

Then, the refrigerant reaches the expansion valve 7 through the pipe 6 and is depressurized there, and then flows into the evaporator 8 where it is evaporated and exhibits a cooling effect. The cool air that has exchanged heat with the evaporator 8 is circulated in the refrigerator by the blower Fa, so that the inside of the refrigerator is cooled and maintained at a predetermined extremely low temperature. The refrigerant discharged from the evaporator 8 enters the accumulator 19 from the pipe 15, and is temporarily stored therein to separate the non-evaporated liquid refrigerant and the gas refrigerant,
The gas refrigerant is sucked into the compressor 2 through the pipe 10.

[0011]

This kind of multi-source refrigerating system is to obtain the cryogenic temperature in the evaporator 8 of the low temperature side refrigerant circuit 102 by repeating the above-mentioned refrigerant circulation, but the low temperature side. Since the refrigerant circuit 102 is filled with the refrigerant having a low boiling point as described above, there is a problem that the high pressure becomes extremely high at the start of operation of the low temperature side refrigerant circuit 102, that is, at the time of pulling down.

Therefore, the low temperature side refrigerant circuit 102 is conventionally used.
This is dealt with by designing a cascade condenser of a size commensurate with the amount of refrigerant to be sealed in, or using a high-temperature side refrigerant circuit 101 having a large refrigerating capacity (using a high-output compressor 32). , Was causing a sharp rise in costs. In some cases, it is unavoidable that the high-pressure pressure rises, and the high-pressure pressure switch 12 is used to stop the compressor 2 of the low-temperature side refrigerant circuit 102, and the high-temperature-side refrigerant circuit is repeatedly operated and stopped. Since the cascade condenser 4 is gradually cooled at 101 to finish the pull-down, there is a problem that it takes a long time to pull-down the low temperature side refrigerant circuit 102.

The present invention has been made to solve the above-mentioned conventional technical problems, and shortens the pull-down time of the low temperature side refrigerant circuit without increasing the refrigerating capacity of the high temperature side refrigerant circuit. It is an object of the present invention to provide a multi-source refrigerating device that can be used.

[0014]

According to a first aspect of the present invention, there is provided a multi-stage refrigeration system which comprises a compressor, a condenser, a decompressor, an evaporator, and the like, which are connected in series in a cyclic manner with a refrigerant pipe, and a compression circuit. Low temperature side refrigerant circuit which is formed by sequentially connecting a machine, a condenser, a decompression device, an evaporator and the like with a refrigerant pipe, and a high boiling point temperature refrigerant is filled in the high temperature side refrigerant circuit, and a low temperature side refrigerant circuit is provided. Is a refrigerant that has a low boiling point and is equipped with a cascade condenser that cross-thermally couples the evaporator of the high temperature side refrigerant circuit and the condenser of the low temperature side refrigerant circuit. A part of the low temperature side refrigerant circuit is coupled to the low pressure side in a heat exchange manner.

In the multi-source refrigeration system of the second aspect of the present invention, a high temperature side refrigerant circuit formed by sequentially connecting a compressor, a condenser, a pressure reducing device, an evaporator and the like in a refrigerant pipe, a compressor, a condenser and a pressure reducing device. A low-temperature side refrigerant circuit that is formed by sequentially connecting a device, an evaporator, an accumulator, etc. in an annular shape with refrigerant pipes, a high-temperature side refrigerant circuit is filled with a high-boiling point refrigerant, and a low-temperature side refrigerant circuit has a low boiling point. While enclosing the refrigerant, it is provided with a cascade condenser that heat-exchanges the evaporator of the high-temperature side refrigerant circuit and the condenser of the low-temperature side refrigerant circuit with a part of the high-pressure side of the low-temperature side refrigerant circuit. It is provided with a structure for precooling in the accumulator.

In the multi-source refrigeration system of the third aspect of the present invention, a high temperature side refrigerant circuit formed by sequentially connecting a compressor, a condenser, a pressure reducing device, an evaporator and the like in a ring with a refrigerant pipe, a compressor, a condenser and a pressure reducing device. A low-temperature side refrigerant circuit that is formed by sequentially connecting a device, an evaporator, an accumulator, etc. in an annular shape with refrigerant pipes, a high-temperature side refrigerant circuit is filled with a high-boiling point refrigerant, and a low-temperature side refrigerant circuit has a low boiling point. It is equipped with a cascade condenser that seals the refrigerant and thermally couples the evaporator of the high temperature side refrigerant circuit and the condenser of the low temperature side refrigerant circuit, and is discharged from the compressor of the low temperature side refrigerant circuit. It is provided with a configuration in which the refrigerant is cooled in the accumulator and then supplied to the cascade condenser, and a configuration in which the refrigerant after being cooled by the cascade condenser is heat-exchanged with the refrigerant on the low pressure side of the high temperature side refrigerant circuit to cool the refrigerant. It is intended.

According to a fourth aspect of the present invention, in the multi-source refrigeration system, a compressor, a condenser, a decompression device, a high temperature side refrigerant circuit in which a compressor, a condenser, a decompression device, an evaporator and the like are sequentially connected in an annular shape by a refrigerant pipe. A low-temperature side refrigerant circuit, which is formed by sequentially connecting a device, an evaporator, and the like with annular refrigerant pipes, a high-temperature side refrigerant circuit is filled with a high-boiling point refrigerant, and a low-temperature side refrigerant circuit is filled with a low-boiling point refrigerant. It is provided with a cascade condenser that seals the evaporator of the high temperature side refrigerant circuit and the condenser of the low temperature side refrigerant circuit in a heat exchange manner, wherein the high pressure side refrigerant of the low temperature side refrigerant circuit is transferred to the low temperature side. The low pressure side of the refrigerant circuit is thermally and thermally coupled to cool the high pressure side refrigerant.

[0018]

According to the multi-source refrigeration system of the present invention, since the high pressure side and the low pressure side (accumulator) of the low temperature side refrigerant circuit are heat-exchanged with each other, the high temperature and high pressure discharged from the compressor of the low temperature side refrigerant circuit. The gas refrigerant can be cooled and easily condensed and liquefied by the cascade condenser. Therefore, the high pressure of the low temperature side refrigerant circuit at the time of pulling down can be suppressed to be low, so that the pulling down time until the temperature reaches the predetermined internal cold storage temperature can be extremely shortened, and quick freezing becomes easy.

Further, the cascade condenser can be made small and the refrigerating capacity of the high temperature side refrigerant circuit can be made small. In particular, the refrigerant discharged from the compressor of the low temperature side refrigerant circuit is first passed through the accumulator,
After that, the cascade condenser and the low-pressure side (subcooler 5) of the high-temperature side refrigerant circuit are passed in this order, so the gasification of the refrigerant in the accumulator can be promoted when the discharge temperature is highest, and the liquid compression of the compressor is prioritized. Can be prevented. At the same time, since the temperature of the discharged refrigerant is lowered, the temperature of the refrigerant discharged from the cascade condenser can be further lowered.

[0020]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of a multi-source refrigeration system 1 of the present invention, FIG.
Is a low temperature side refrigerant circuit 5 that constitutes the multi-source refrigeration system 1 of the present invention.
2 is a partially cutaway side view of the accumulator 9 of FIG. 2, and FIG. 3 is a plan view of the accumulator 9 of the low temperature side refrigerant circuit 52 which constitutes the multi-source refrigeration system 1 of the present invention. The multi-source refrigeration system 1 of the present invention includes a high temperature side refrigerant circuit 51 (refrigerant having a high boiling point) and a low temperature side refrigerant circuit 52 (refrigerant having a low boiling point). The discharge side pipe 3 of the compressor 2 of the low temperature side refrigerant circuit 52 is connected to the condenser 21 in the shape of a closed container after passing through the accumulator 9, and the outlet side pipe 1 of the condenser 21.
4 is connected to the subcooler 5. Further, the outlet side pipe 6 of the subcooler 5 is connected to an evaporator 8 via an expansion valve 7 which is a pressure reducing device.

The outlet side pipe 15 of the evaporator 8 is connected to the accumulator 9, and the accumulator 9 is connected to the suction side pipe 10 of the compressor 2 to form an annular low temperature side refrigerant circuit 52.
Are configured. In FIG. 1, Fa is a blower for cooling the inside of the refrigerator, 1
2 is a high pressure switch. The expansion tank 1 is provided between the discharge side pipe 3 of the compressor 2 and the outlet side pipe 15 of the evaporator 8.
Further, the expansion valve 7 divides the low temperature side refrigerant circuit 52 into a high pressure side and a low pressure side, and detects the temperature of the outlet side pipe 15 of the evaporator 8 to adjust the opening degree.

On the other hand, a condenser 34 is connected to the discharge side pipe 33 of the compressor 32 of the high temperature side refrigerant circuit 51, and the condenser 34
Is connected to the liquid receiver 35. Then, the outlet side pipe 36 of the liquid receiver 35 becomes the evaporator 41 after passing through the expansion valve 37, passes through the inside of the subcooler 5 of the low temperature side refrigerant circuit 52, and further passes through the inside of the condenser 21 of the low temperature side refrigerant circuit 52. They pass through in a heat exchange manner and are connected to the accumulator 38. The evaporator 41 of the high temperature side refrigerant circuit 51 and the condenser 21 of the low temperature side refrigerant circuit 52 constitute the cascade condenser 4. The accumulator 38 is a suction side pipe 39 of the compressor 32.
To form an annular high temperature side refrigerant circuit 51. The expansion valve 37 detects the temperature of the outlet side pipe 36 of the evaporator 41 and adjusts the opening degree. Further, 40 is a high pressure switch, and Fb is a blower for air-cooling the condenser 34.

Here, the accumulator 9 provided on the low pressure side of the low temperature side refrigerant circuit 52 (the suction side of the compressor 2).
2 is a system in which the pipes 10 and 15 are connected to the upper portion of a substantially cylindrical container 9a which is closed as shown in FIGS. The liquid refrigerant is then separated into gas and liquid, and only the gas component is pipe 10
It is configured to be sucked into the compressor 2 more. The lower portion of the discharge side pipe 3 (high-pressure side pipe) of the compressor 2 enters the container 9a from the side surface of the container 9a, makes a U-turn inside, and is pulled out from the side surface of the container 9a as well. Therefore, the piping in the accumulator 9 mainly exchanges heat with the liquid refrigerant.

Next, the operation will be described. High temperature side refrigerant circuit 51
For example, it is assumed that the R22 refrigerant is enclosed in a predetermined amount and the low temperature side refrigerant circuit 52 is enclosed with the R23 refrigerant in a prescribed amount. When the multi-source refrigeration system 1 is operated by the control device (not shown), for example, the high temperature side refrigerant circuit 51 is first operated, and then the low temperature side refrigerant circuit 52 is operated after the temperature of the cascade condenser 4 is lowered to a predetermined temperature. I shall. When the compressor 32 of the high temperature side refrigerant circuit 51 is activated and the high temperature and high pressure gas refrigerant is discharged to the pipe 33, the refrigerant flows from the pipe 33 into the condenser 34, where it is air-cooled by the blower Fb and condensed and liquefied. It flows into the liquid receiver 35.

The liquid refrigerant is separated into gas and liquid in the liquid receiver 35, the liquid refrigerant is decompressed by the expansion valve 37, flows into the evaporator 41, and first performs a cooling action in the subcooler 5 while evaporating.
The refrigerant discharged from the subcooler 5 flows into the cascade condenser 4, evaporates there to exert a cooling effect, and then is sucked into the compressor 32 through the pipe 39 through the accumulator 38.

By the operation of the high temperature side refrigerant circuit 51,
For example, when the temperature of the cascade condenser 4 drops to a predetermined temperature, the control device starts the operation of the low temperature side refrigerant circuit 52. Then, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the cascade condenser 4 formed by the condenser 21 through the pipe 3. Since the inside of the cascade condenser 4 is cooled by the evaporator 41 of the high temperature side refrigerant circuit 51 as described above, the inflowing high temperature gas refrigerant is cooled there and condensed and liquefied. Then, the refrigerant flows into the subcooler 5 via the pipe 14. Since the inside of the subcooler 5 is also cooled by the evaporator 41 of the high temperature side refrigerant circuit 51 as described above, the refrigerant is further cooled, condensed and liquefied, and flows out to the pipe 6.

The refrigerant reaches the expansion valve 7 through the pipe 6 and is depressurized there, then flows into the evaporator 8 where it is evaporated and exhibits a cooling effect. The cool air that has exchanged heat with the evaporator 8 is circulated in the refrigerator by the blower Fa, so that the inside of the refrigerator is cooled and maintained at a predetermined extremely low temperature. The refrigerant exiting the evaporator 8 enters the accumulator 9 through the pipe 15, is temporarily stored therein, and the non-evaporated liquid refrigerant and the gas refrigerant are separated as described above, and the gas refrigerant is sucked into the compressor 2 through the pipe 10. .

The high-temperature high-pressure gas refrigerant discharged from the compressor 2 of the low-temperature side refrigerant circuit 52 passes through the accumulator 9 while passing through the pipe 3. Since a low-temperature gas refrigerant and a non-evaporated liquid refrigerant are stored in the accumulator 9, the refrigerant discharged from the compressor 2 receives a cooling action, and if the temperature immediately after discharge is + 100 ° C., for example,
At the time of flowing into the condenser 21, the temperature drops to about + 76 ° C., for example. Therefore, the refrigerant of the low temperature side refrigerant circuit 52 entering the cascade condenser 4 is more easily condensed, the high pressure of the low temperature side refrigerant circuit 52 is suppressed to a low level, and the stop by the high pressure switch 12 is also prevented or reduced. Time is reduced.

That is, when the multi-source refrigeration system 1 of the embodiment is operated, the temperature of the evaporator 41 of the high temperature side refrigerant circuit 51 is −25.0 ° C. at the inlet side of the cascade condenser 4 and at the outlet side of the cascade condenser 4. The pipe 36 has a temperature of −24.4 ° C., and the temperature of the pipe 3 of the low-temperature side refrigerant circuit 52 has already dropped to about + 76.3 ° C. at the inlet side of the cascade condenser 4 due to the cooling by the accumulator 9 to facilitate the condenser. The pipe 14 on the outlet side of the cascade condenser 4 has dropped to −23.0 ° C. And the temperature of the evaporator 8 of the low temperature side refrigerant circuit 52 reached -70 degreeC, and the internal temperature of -60 degreeC was acquired.

As described above, in the multi-source refrigeration system 1 of the present invention, the high temperature and high pressure gas refrigerant discharged from the compressor 2 of the low temperature side refrigerant circuit 52 is cooled in the process of passing through the pipe 3 in the accumulator 9. Since it is configured, the cascade condenser 4 can be easily condensed and liquefied. As a result, the capacity of the cascade condenser 4 can be reduced, and the refrigerating capacity of the high temperature side refrigerant circuit 51 can be reduced.
Further, since the high-temperature and high-pressure gas refrigerant is passed through the accumulator 9, the suction gas to the compressor 2 is sufficiently heated, so that the risk of liquid back is eliminated. In particular, since the high pressure of the low temperature side refrigerant circuit 52 at the time of pulling down is suppressed to a low level, the pulling down time until reaching a predetermined internal temperature can be shortened, and quick freezing can be performed.

[0031]

As described above in detail, according to the present invention, since the high pressure side and the low pressure side (accumulator) of the low temperature side refrigerant circuit are heat exchange coupled, the refrigerant is discharged from the compressor of the low temperature side refrigerant circuit. Further, the high-temperature and high-pressure gas refrigerant can be cooled and easily condensed and liquefied by the cascade condenser. Therefore, the high pressure of the low temperature side refrigerant circuit at the time of pulling down can be suppressed to be low, so that the pulling down time until the temperature reaches the predetermined internal cold storage temperature can be extremely shortened, and quick freezing becomes easy.

Further, the cascade condenser can be made small and the refrigerating capacity of the high temperature side refrigerant circuit can be made small. In particular, the refrigerant discharged from the compressor of the low temperature side refrigerant circuit is first passed through the accumulator,
After that, the cascade condenser and the low-pressure side (subcooler) of the high-temperature side refrigerant circuit are passed in this order, so the gasification of the refrigerant in the accumulator can be promoted at the highest discharge temperature, and liquid compression of the compressor is prioritized. Can be prevented.
At the same time, since the temperature of the discharged refrigerant is lowered, the temperature of the refrigerant discharged from the cascade condenser can be further lowered.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram of a multi-source refrigeration system of the present invention.

FIG. 2 is a side view of the accumulator of the present invention.

FIG. 3 is a plan view of the accumulator of the present invention.

FIG. 4 is a refrigerant circuit diagram of a conventional multi-source refrigeration system.

[Explanation of symbols]

 1 Multi-Refrigerator 2 Compressor 3 Piping 4 Cascade condenser 5 Subcooler 7 Expansion valve 8 Evaporator 9 Accumulator 9a Container 21 Condenser 32 Compressor 34 Condenser 37 Expansion valve 41 Evaporator 51 High temperature side refrigerant circuit 52 Low temperature side refrigerant circuit

Claims (4)

[Claims] 1. A high temperature side refrigerant circuit comprising a compressor, a condenser, a pressure reducing device, an evaporator and the like which are sequentially connected in an annular shape by a refrigerant pipe,
A low-temperature side refrigerant circuit, in which a compressor, a condenser, a decompression device, an evaporator, etc. are sequentially connected in an annular shape by refrigerant pipes, and a high-temperature side refrigerant circuit is filled with a high boiling point refrigerant, and a low-temperature side refrigerant circuit In the multi-source refrigeration system, in which a refrigerant having a low boiling point is sealed in, and a cascade condenser that thermally couples the evaporator of the high temperature side refrigerant circuit and the condenser of the low temperature side refrigerant circuit in a heat exchange manner, A multi-source refrigeration system having a configuration in which a part of the side is coupled to the low pressure side of the low temperature side refrigerant circuit in a heat exchange manner. 2. A high temperature side refrigerant circuit comprising a compressor, a condenser, a pressure reducing device, an evaporator, etc., which are sequentially connected in an annular shape by a refrigerant pipe,
It is equipped with a low temperature side refrigerant circuit consisting of a compressor, a condenser, a decompressor, an evaporator, an accumulator, etc., which are sequentially connected by a refrigerant pipe, and a high temperature side refrigerant circuit is filled with a refrigerant having a high boiling point temperature, and a low temperature side. In a multi-source refrigeration system that includes a refrigerant having a low boiling point in the refrigerant circuit, and a cascade condenser that couples the evaporator of the high temperature side refrigerant circuit and the condenser of the low temperature side refrigerant circuit in a heat exchange manner, the low temperature side refrigerant circuit A multi-source refrigeration system comprising a structure for pre-cooling a part of the high pressure side of the inside of the accumulator. 3. A high temperature side refrigerant circuit comprising a compressor, a condenser, a pressure reducing device, an evaporator and the like which are sequentially connected in an annular shape by a refrigerant pipe,
It is equipped with a low temperature side refrigerant circuit consisting of a compressor, a condenser, a decompressor, an evaporator, an accumulator, etc., which are sequentially connected by a refrigerant pipe, and a high temperature side refrigerant circuit is filled with a refrigerant having a high boiling point temperature, and a low temperature side. In a multi-source refrigeration system that includes a refrigerant having a low boiling point in the refrigerant circuit, and a cascade condenser that couples the evaporator of the high temperature side refrigerant circuit and the condenser of the low temperature side refrigerant circuit in a heat exchange manner, the low temperature side refrigerant circuit The refrigerant discharged from the compressor is cooled in the accumulator and then supplied to the cascade condenser, and the refrigerant after being cooled by the cascade condenser is heat exchanged with the refrigerant on the low pressure side of the high temperature side refrigerant circuit. A multi-source refrigeration system, which is characterized in that it has a structure for cooling by means of cooling. 4. A high temperature side refrigerant circuit comprising a compressor, a condenser, a pressure reducing device, an evaporator, etc., which are sequentially connected in an annular shape by a refrigerant pipe,
A low-temperature side refrigerant circuit, in which a compressor, a condenser, a decompression device, an evaporator, etc. are sequentially connected in an annular shape by refrigerant pipes, and a high-temperature side refrigerant circuit is filled with a high boiling point refrigerant, and a low-temperature side refrigerant circuit In the multi-source refrigeration system, in which a refrigerant having a low boiling point is sealed in, and a cascade condenser that thermally couples the evaporator of the high temperature side refrigerant circuit and the condenser of the low temperature side refrigerant circuit in a heat exchange manner, A multi-refrigerating device characterized in that the high-pressure side refrigerant is cooled by heat-exchangeably coupling the low-temperature side refrigerant circuit to the low-pressure side refrigerant circuit.