WO2024014026A1

WO2024014026A1 - Refrigerator, refrigerator control device, refrigerator control method, and program

Info

Publication number: WO2024014026A1
Application number: PCT/JP2023/005771
Authority: WO
Inventors: 真悟佐藤
Original assignee: 三菱重工業株式会社
Priority date: 2022-07-13
Filing date: 2023-02-17
Publication date: 2024-01-18
Also published as: JP2024010808A

Abstract

This refrigerator comprises a low-stage compressor for compressing a low-pressure refrigerant to a medium-pressure refrigerant, a high-stage compressor for compressing the medium-pressure refrigerant to a high-pressure refrigerant, a low-pressure pipeline which is connected to the low-stage compressor and through which the low-pressure refrigerant flows, a medium-pressure pipeline which is connected between the low-stage compressor and the high-stage compressor and through which the medium-pressure refrigerant flows, a high-pressure pipeline which is connected to the high-stage compressor and through which the high-pressure refrigerant flows, a first circuit extending from the high-pressure pipeline to the low-pressure pipeline, and a pressure equalizing circuit capable of performing pressure equalization between the first circuit and the medium-pressure pipeline, wherein: the first circuit is provided with a first valve for opening and closing a flow passage in the first circuit; and the pressure equalizing circuit is provided with a pressure equalizing valve for opening and closing a flow passage in the pressure equalizing circuit.

Description

Refrigerator, refrigerator control device, refrigerator control method, and program

The present disclosure relates to a refrigerator, a refrigerator control device, a refrigerator control method, and a program.
This application claims priority to Japanese Patent Application No. 2022-112320 filed in Japan on July 13, 2022, the contents of which are incorporated herein.

Patent Document 1 discloses a configuration in which, in a refrigerator including a plurality of outdoor units each equipped with a compressor arranged in parallel, the pressure of oil supplied to the compressor together with refrigerant is adjusted between the plurality of outdoor units by an oil equalizing pipe. ing.

Japanese Patent Application Publication No. 2000-146324

By the way, in a refrigerator, a plurality of compressors may be provided in series. In this case, the refrigerator includes a low-stage compressor that compresses low-pressure refrigerant into intermediate-pressure refrigerant, and a high-stage compressor that compresses intermediate-pressure refrigerant into high-pressure refrigerant.
In such a refrigerator, a low-pressure refrigerant flows through a pipe on the upstream side of the refrigerant flow direction with respect to the low-stage compressor. Medium-pressure refrigerant compressed by the low-stage compressor flows through the pipe between the low-stage compressor and the high-stage compressor. High-pressure refrigerant flows through the piping on the downstream side of the refrigerant flow direction with respect to the high-stage compressor. Therefore, during operation of the refrigerator, the low-pressure piping upstream of the low-stage compressor, the intermediate-pressure piping between the low-stage compressor and the high-stage compressor, and the high-pressure piping downstream of the high-stage compressor are connected. There is a difference in refrigerant pressure between the two. When the refrigerator stops operating, it may be desirable to equalize the pressure between the low pressure piping, intermediate pressure piping, and high pressure piping in order to stably stop the refrigerator.
However, in a configuration including a plurality of compressors, the configuration tends to become complicated in order to equalize the pressures among the low pressure piping, intermediate pressure piping, and high pressure piping.

The present disclosure has been made to solve the above problems, and aims to provide a refrigerator, a refrigerator control device, a refrigerator control method, and a program that can easily equalize the pressure.

In order to solve the above problems, a refrigerator according to the present disclosure includes: a low-stage compressor that compresses a low-pressure refrigerant into an intermediate-pressure refrigerant; a high-stage compressor that compresses the intermediate-pressure refrigerant into a high-pressure refrigerant; a low-pressure pipe connected to the compressor and through which the low-pressure refrigerant flows; an intermediate-pressure pipe connected between the low-stage compressor and the high-stage compressor and through which the medium-pressure refrigerant flows; A high-pressure pipe connected to the high-pressure pipe through which the high-pressure refrigerant flows, a first circuit extending from the high-pressure pipe to the low-pressure pipe, and a pressure equalizing circuit capable of equalizing the pressure between the first circuit and the medium-pressure pipe. , the first circuit includes a first valve that opens and closes a flow path in the first circuit, and the pressure equalization circuit includes a pressure equalization valve that opens and closes a flow path in the pressure equalization circuit.

A refrigerator control device according to the present disclosure includes a low-stage compressor that compresses a low-pressure refrigerant into an intermediate-pressure refrigerant, a high-stage compressor that compresses the intermediate-pressure refrigerant into a high-pressure refrigerant, and a high-stage compressor that is connected to the low-stage compressor. , a low-pressure pipe through which the low-pressure refrigerant flows, an intermediate-pressure pipe connected between the low-stage compressor and the high-stage compressor, and an intermediate-pressure pipe through which the medium-pressure refrigerant flows, and a high-pressure pipe connected to the high-stage compressor; a high-pressure pipe through which a refrigerant flows; a first valve control unit that is capable of controlling a refrigerator and opens a first valve of a first circuit extending to the high-pressure pipe and the low-pressure pipe; A pressure equalizing valve control unit that opens a pressure equalizing valve of a pressure equalizing circuit capable of equalizing the pressure between the pressure piping and the pressure piping.

A method for controlling a refrigerator according to the present disclosure includes a low-stage compressor that compresses a low-pressure refrigerant into an intermediate-pressure refrigerant, a high-stage compressor that compresses the intermediate-pressure refrigerant into a high-pressure refrigerant, and a high-stage compressor that is connected to the low-stage compressor. , a low-pressure pipe through which the low-pressure refrigerant flows, an intermediate-pressure pipe connected between the low-stage compressor and the high-stage compressor, and an intermediate-pressure pipe through which the medium-pressure refrigerant flows, and a high-pressure pipe connected to the high-stage compressor; A method for controlling a refrigerator, comprising: a high-pressure pipe through which a refrigerant flows; The method includes the steps of opening a first valve of a circuit, and opening a pressure equalizing valve of a pressure equalizing circuit capable of equalizing the pressure between the first circuit and the intermediate pressure piping.

A program according to the present disclosure includes: a low-stage compressor that compresses a low-pressure refrigerant into an intermediate-pressure refrigerant; a high-stage compressor that compresses the intermediate-pressure refrigerant into a high-pressure refrigerant; a low-pressure pipe connected between the low-stage compressor and the high-stage compressor and through which the medium-pressure refrigerant flows; and a high-pressure pipe connected to the high-stage compressor and through which the high-pressure refrigerant flows. A first valve of a first circuit extending to the high-pressure pipe and the low-pressure pipe when the operation of the low-stage compressor and the high-stage compressor is stopped. and opening a pressure equalizing valve of a pressure equalizing circuit capable of equalizing the pressure between the first circuit and the intermediate pressure pipe.

According to the refrigerator, refrigerator control device, refrigerator control method, and program of the present disclosure, it is possible to provide a refrigerator that is easy to pressure equalize.

FIG. 1 is a diagram showing the configuration of a refrigerator according to an embodiment of the present disclosure. FIG. 2 is a diagram showing the configuration of a first circuit and a pressure equalization circuit provided in a refrigerator according to an embodiment of the present disclosure. FIG. 1 is a functional block diagram of a refrigerator control device according to an embodiment of the present disclosure. 1 is a flowchart illustrating a procedure of a method for controlling a refrigerator according to an embodiment of the present disclosure. FIG. 2 is a diagram showing the flow of refrigerant during normal operation in the refrigerator according to the embodiment of the present disclosure. FIG. 2 is a diagram showing the flow of refrigerant when operation is stopped in the refrigerator according to the embodiment of the present disclosure. FIG. 1 is a diagram showing a hardware configuration of a refrigerator control device according to an embodiment of the present disclosure.

Hereinafter, a refrigerator, a refrigerator control device, a refrigerator control method, and a program according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 7.
(Composition of refrigerator)
As shown in FIG. 1, the refrigerator 1 mainly includes a compression section 2, a condenser 3, an expansion valve 4, and a receiver 5.
Refrigerator 1 is an outdoor unit that constitutes a refrigeration cycle system.
The refrigerator 1 circulates refrigerant between it and an indoor unit (not shown) that constitutes a refrigeration cycle system.
Refrigerator 1 cools refrigerant and generates liquid refrigerant.
The refrigerator 1 supplies the generated liquid refrigerant to an indoor unit (not shown).
The refrigerator 1 sucks refrigerant whose temperature has increased by performing heat exchange with the indoor unit from the indoor unit.
In this embodiment, the refrigerant is, for example, carbon dioxide (CO ₂ ).
The refrigerant may be other than carbon dioxide.

The compression section 2 compresses refrigerant circulated from the indoor unit.
The compression section 2 mainly includes an inlet accumulator (accumulator) 21, a sub-accumulator 22, a low-stage compressor 23, an intercooler 24, an intermediate accumulator 25, a high-stage compressor 26, and an oil separator 27. We are prepared.

The inlet accumulator 21 sucks refrigerant from the indoor unit through the first pipe 101.
The inlet accumulator 21 separates refrigerant sucked in from an indoor unit (not shown) into gas refrigerant and liquid refrigerant.
Refrigerant discharged from an indoor unit (not shown) flows into the inlet accumulator 21 through the first pipe 101.
The inlet accumulator 21 supplies the gas refrigerant separated within the inlet accumulator 21 to the sub-accumulator 22 through the second pipe 102.
The second pipe 102 connects the inlet accumulator 21 and the sub-accumulator 22.

Oil contained in the liquid refrigerant separated at the inlet accumulator 21 is sent to the sub-accumulator 22 through the first oil return pipe 401.
The first oil return pipe 401 connects the bottom of the inlet accumulator 21 and the second pipe 102.
The oil supplied into the second pipe 102 through the first oil return pipe 401 mixes with the gas refrigerant flowing inside the second pipe 102 and is sent to the sub-accumulator 22.

The gas refrigerant separated at the inlet accumulator 21 flows into the sub-accumulator 22 through the second pipe 102 .
The sub-accumulator 22 separates gas refrigerant and liquid refrigerant.
The sub-accumulator 22 separates liquid refrigerant contained in the gas refrigerant separated by the inlet accumulator 21.
The sub-accumulator 22 supplies the gas refrigerant separated within the sub-accumulator 22 to the low stage compressor 23 through the third pipe 103.
The third pipe 103 connects the sub-accumulator 22 and the low-stage compressor 23.

The low-stage compressor 23 sucks the gas refrigerant separated by the sub-accumulator 22 through the third pipe 103 due to the negative pressure generated by the operation of the low-stage compressor 23 .
The low stage compressor 23 compresses the sucked gas refrigerant.
In this embodiment, the low-stage compressor 23 is a two-stage compressor that includes a first rotary compression section (compression section) 231 and a first scroll compression section (compression section) 232 in series.
The first rotary compression section 231 compresses the gas refrigerant sucked through the third pipe 103.
The first scroll compression section 232 further compresses the refrigerant compressed by the first rotary compression section 231.
The refrigerant compressed in the first scroll compression section 232 is discharged to the intercooler 24 through the fourth pipe 104.
The fourth pipe 104 connects the low stage compressor 23 and the intercooler 24.

Intercooler 24 and intermediate accumulator 25 are arranged between low stage compressor 23 and high stage compressor 26.
The refrigerant compressed by the low-stage compressor 23 is sent to the intercooler 24 through the fourth pipe 104.
The intercooler 24 cools the refrigerant sent therein.
In this embodiment, the intercooler 24 is, for example, an air-cooled type.
Intercooler 24 includes an intercooler main body 241 and a fan 242.
The intercooler main body 241 has a flow path (not shown) for the refrigerant compressed by the low stage compressor 23.
The intercooler main body 241 exchanges heat between the refrigerant flowing inside the flow pipe and the outside air outside the flow pipe.
The fan 242 sends air to the intercooler body 241 to improve the efficiency of heat exchange in the intercooler body 241.
The refrigerant cooled by the intercooler 24 is sent to the intermediate accumulator 25 through the fifth pipe 105.
The fifth pipe 105 connects the intercooler 24 and the intermediate accumulator 25.

The intermediate accumulator 25 is cooled by the intercooler 24 and separates the refrigerant sent through the fifth pipe 105 into a gas refrigerant and a liquid refrigerant.
The gas refrigerant separated in the intermediate accumulator 25 is supplied to the high stage compressor 26 through the sixth pipe 106.
The sixth pipe 106 connects the intermediate accumulator 25 and the high-stage compressor 26.

The oil contained in the liquid refrigerant separated in the intermediate accumulator 25 is sent to the high stage compressor 26 through the second oil return pipe 402.
The second oil return pipe 402 connects the bottom of the intermediate accumulator 25 and the sixth pipe 106.
The oil supplied into the sixth pipe 106 through the second oil return pipe 402 mixes with the refrigerant flowing inside the sixth pipe 106 and is sent to the high stage compressor 26.

The high-stage compressor 26 sucks the gas refrigerant separated by the intermediate accumulator 25 through the sixth pipe 106 due to the negative pressure generated by the operation of the high-stage compressor 26 .
The high stage compressor 26 compresses the sucked gas refrigerant.
In this embodiment, the high-stage compressor 26 is a two-stage compressor that includes a second rotary compression section (compression section) 261 and a second scroll compression section (compression section) 262 in series.
The second rotary compression section 261 compresses the gas refrigerant sucked through the sixth pipe 106.
The second scroll compression section 262 further compresses the high temperature and high pressure refrigerant compressed by the second rotary compression section 261.
The refrigerant compressed by the high-stage compressor 26 is sent to the oil separator 27 through the seventh pipe 107.
The seventh pipe 107 connects the high-stage compressor 26 and the oil separator 27.

The oil separator 27 separates oil contained in the refrigerant from the refrigerant compressed by the high-stage compressor 26 and sent through the seventh pipe 107.
The refrigerant from which oil has been separated by the oil separator 27 is sent to the condenser 3 through the eighth pipe 108.
The eighth pipe 108 connects the oil separator 27 and the capacitor 3.

The oil separated by the oil separator 27 is discharged into the oil tank 28 through the third oil return pipe 403.
The third oil return pipe 403 connects the oil separator 27 and the oil tank 28.
The oil tank 28 stores oil discharged from the oil separator 27 through the third oil return pipe 403.

The oil stored in the oil tank 28 is returned to the low stage compressor 23 and the high stage compressor 26 through a fourth oil return pipe 404 and a fifth oil return pipe 405.
An oil cooler 29 is provided in the middle of the fourth oil return pipe 404 and the fifth oil return pipe 405.
The oil cooler 29 cools the oil passing through the fourth oil return pipe 404 and the fifth oil return pipe 405.

The condenser 3 cools and condenses the refrigerant sent through the eighth pipe 108.
In this embodiment, the capacitor 3 is, for example, an air-cooled type.
The capacitor 3 includes a capacitor body 31 and a fan 32.
The condenser body 31 has a flow path (not shown) for the refrigerant fed through the eighth pipe 108.
Through the eighth pipe 108, heat exchange is performed between the refrigerant flowing inside the flow pipe and the outside air outside the flow pipe.
The fan 32 sends air to the capacitor body 31 to improve the efficiency of heat exchange in the capacitor body 31.
The refrigerant cooled by the condenser 3 is sent to the expansion valve 4 through the ninth pipe 109.
The ninth pipe 109 connects the condenser 3 and the expansion valve 4.

The expansion valve 4 expands the refrigerant condensed in the condenser 3 and sent through the ninth pipe 109.
The expansion valve 4 sends the expanded refrigerant to the receiver 5 through the tenth pipe 110.
The tenth pipe 110 connects the expansion valve 4 and the receiver 5.

The receiver 5 separates the refrigerant expanded by the expansion valve 4 and sent through the tenth pipe 110 into a gas refrigerant and a liquid refrigerant.
The receiver 5 supplies the separated liquid refrigerant to an indoor unit (not shown) through the eleventh pipe 111.

In this embodiment, a subcooling heat exchanger 6 is provided in the middle of the eleventh pipe 111.
The supercooling heat exchanger 6 further cools (supercools) the liquid refrigerant supplied to the indoor unit through the eleventh pipe 111.
The subcooling heat exchanger 6 includes a first flow path (not shown) for liquid refrigerant sent through the eleventh pipe 111 and a second flow path (not shown) for the liquid refrigerant sent through the twelfth pipe 112. ,have.

The twelfth pipe 112 branches from the eleventh pipe 111.
One end of the twelfth pipe 112 is branched from the eleventh pipe 111 on the upstream side of the subcooling heat exchanger 6 in the flow direction of the refrigerant in the eleventh pipe 111. .
The other end of the twelfth pipe 112 is connected to the second flow path of the subcooling heat exchanger 6.
The twelfth pipe 112 is equipped with an injection valve 61 and an expansion valve 62 for a supercooling heat exchanger.

The injection valve 61 opens and closes the liquid refrigerant flow path within the twelfth pipe 112 .
The opening and closing operations of the injection valve 61 are controlled by the control device 300.
When the injection valve 61 is opened, liquid refrigerant is supplied to the supercooling heat exchanger 6 through the twelfth pipe 112.
When the injection valve 61 is closed, the liquid refrigerant is not supplied to the subcooling heat exchanger 6 through the twelfth pipe 112.

The subcooling heat exchanger expansion valve 62 expands the liquid refrigerant passing through the twelfth pipe 112.
The subcooling heat exchanger 6 has a first flow path (not shown) for the liquid refrigerant sent through the eleventh pipe 111 and a second flow path for the liquid refrigerant sent through the twelfth pipe 112. The flow directions of the two are opposite to each other.
The supercooling heat exchanger 6 exchanges heat between the liquid refrigerant in the first flow path and the liquid refrigerant in the second flow path, which flow in opposite directions.
In the subcooling heat exchanger 6, the liquid refrigerant in the first flow path is cooled by heat exchange with the liquid refrigerant in the second flow path expanded by the subcooling heat exchanger expansion valve 62.
The liquid refrigerant cooled in the first flow path of the supercooling heat exchanger 6 is supplied to the indoor unit through the eleventh pipe 111.

In the supercooling heat exchanger 6, the temperature of the liquid refrigerant in the second flow path increases through heat exchange with the liquid refrigerant in the first flow path.
The liquid refrigerant heated in the second flow path of the subcooling heat exchanger 6 is supplied to the high stage compressor 26 through the injection circuit 120.

The injection circuit 120 connects the subcooling heat exchanger 6 and the sixth pipe 106.
The injection circuit 120 is connected to a sixth pipe 106 that is disposed on the downstream side of the intermediate accumulator 25 in the flow direction of the refrigerant.
The injection circuit 120 is connected to the sixth pipe 106 between the intercooler 24 and the high-stage compressor 26.
The injection circuit 120 sends the liquid refrigerant heated by the subcooling heat exchanger 6 to the high stage compressor 26 through the sixth pipe 106.
The sixth pipe 106 is connected to the high stage compressor 26 between the second rotary compression section 261 and the second scroll compression section 262.
The injection circuit 120 feeds the liquid refrigerant into the high-stage compressor 26 on the downstream side of the second rotary compression section 261 .

The injection circuit 120 injects liquid refrigerant into the high-stage compressor 26 through the sixth pipe 106 when the injection valve 61 is opened under the control of the control device 300 .
The injection circuit 120 does not inject liquid refrigerant into the high-stage compressor 26 when the injection valve 61 is closed under the control of the control device 300 .

Such a refrigerator 1 has a low pressure pipe 100L, a medium pressure pipe 100M, and a high pressure pipe 100H.
The low-pressure refrigerant before being compressed by the low-stage compressor 23 flows through the low-pressure pipe 100L.
The low pressure refrigerant flowing through the low pressure pipe 100L has the lowest pressure in the refrigerator 1.
The low pressure pipe 100L is connected to the low stage compressor 23.
The low-pressure pipe 100L includes a first pipe 101, a second pipe 102, and a third pipe 103, which are arranged on the upstream side of the low-stage compressor 23 in the flow direction of the refrigerant.

The low stage compressor 23 compresses low pressure refrigerant into medium pressure refrigerant.
Medium pressure refrigerant compressed by the low stage compressor 23 flows through the medium pressure pipe 100M.
The medium pressure pipe 100M is connected between the low stage compressor 23 and the high stage compressor 26.
The medium pressure pipe 100M includes a fourth pipe 104, a fifth pipe 105, and a sixth pipe 106.

The high-stage compressor 26 compresses medium-pressure refrigerant into high-pressure refrigerant.
A high-pressure refrigerant compressed by the high-stage compressor 26 flows through the high-pressure pipe 100H.
The high pressure refrigerant flowing through the high pressure pipe 100H has the highest pressure in the refrigerator 1.
High pressure piping 100H is connected to high stage compressor 26.
High pressure piping 100H is arranged between high stage compressor 26 and expansion valve 4.
The high pressure pipe 100H includes a seventh pipe 107, an eighth pipe 108, and a ninth pipe 109.

The refrigerator 1 includes a pressure equalization mechanism 500.
The pressure equalization mechanism 500 attempts to equalize the pressure between the low pressure pipe 100L, the medium pressure pipe 100M, and the high pressure pipe 100H when the operation is stopped.
As shown in FIGS. 1 and 2, the pressure equalization mechanism 500 includes a first circuit 510 and a pressure equalization circuit 520.

The first circuit 510 extends from the high pressure pipe 100H to the low pressure pipe 100L.
The first circuit 510 connects the downstream side of the high-pressure refrigerant flow direction with respect to the oil separator 27 in the high-pressure pipe 100H, and the downstream side of the low-pressure refrigerant flow direction with respect to the inlet accumulator 21 in the low-pressure pipe 100L. .
One end 510a of the first circuit 510 is connected to the eighth pipe 108 on the downstream side of the oil separator 27 in the high-pressure refrigerant flow direction in the high-pressure pipe 100H.
The other end 510b of the first circuit 510 is connected to the second pipe 102 on the downstream side of the inlet accumulator 21 in the low-pressure refrigerant flow direction in the low-pressure pipe 100L.

The first circuit 510 includes a first valve 511 and a flow rate adjustment mechanism 512.
The first valve 511 opens and closes the flow path within the first circuit 510.
When the first valve 511 is opened, the first circuit 510 supplies high-pressure refrigerant that flows through the high-pressure pipe 100H and has a higher pressure and temperature than the low-pressure refrigerant to the low-pressure pipe 100L.
The opening and closing operations of the first valve 511 are controlled by the control device 300.
When the first valve 511 is opened, high-pressure refrigerant is supplied to the low-pressure pipe 100L through the first circuit 510 and the high-pressure pipe 100H. Thereby, pressure equalization between the high pressure pipe 100H and the low pressure pipe 100L is achieved.
When the first valve 511 is closed, no pressure equalization through the first circuit 510 takes place.

The flow rate adjustment mechanism 512 is disposed in the first circuit 510 on the downstream side of the first valve 511 in the refrigerant flow direction in the first circuit 510 .
The flow rate adjustment mechanism 512 is, for example, a capillary pipe.
The refrigerant flowing through the first circuit 510 is subjected to flow path resistance by a flow rate adjustment mechanism 512 made of capillary piping, and its flow rate is reduced.
The flow rate adjustment mechanism 512 may have a configuration other than capillary piping.

The pressure equalization circuit 520 is capable of connecting the first circuit 510 and the injection circuit 120.
The pressure equalization circuit 520 connects the injection circuit 120 and a position 513 on the downstream side of the first circuit 510 in the flow direction of the high-pressure refrigerant.
One end 520a of the pressure equalization circuit 520 is connected to the injection circuit 120.
One end 520a of the pressure equalization circuit 520 is connected to the injection circuit 120 between the subcooling heat exchanger 6 and the sixth pipe 106.
The other end 520b of the pressure equalizing circuit 520 is connected to the first circuit 510.
The other end 520b of the pressure equalizing circuit 520 is connected to a position 513 in the first circuit 510 on the downstream side of the first valve 511 in the flow direction of the high-pressure refrigerant.

The pressure equalization circuit 520 includes a pressure equalization valve 521.
The pressure equalization valve 521 opens and closes the flow path within the pressure equalization circuit 520.
The pressure equalization circuit 520 connects the first circuit 510 and the injection circuit 120 when the pressure equalization valve 521 is opened.
When the pressure equalization valve 521 is opened, the first circuit 510 and the injection circuit 120 communicate with each other through the pressure equalization circuit 520.
When the pressure equalization valve 521 is opened, the high pressure pipe 100H and the low pressure pipe 100L, which are communicated through the first circuit 510, communicate with the medium pressure pipe 100M via the pressure equalization circuit 520 and the injection circuit 120.
When the pressure equalization valve 521 is opened, the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L are equalized.
The opening and closing operations of the pressure equalizing valve 521 are controlled by the control device 300.

(Configuration of control device)
The control device 300 is capable of controlling the refrigerator 1.
The control device 300 controls the opening and closing operations of at least the low stage compressor 23, the high stage compressor 26, the injection valve 61, the first valve 511, and the pressure equalizing valve 521.
As shown in FIG. 3, the control device 300 includes a Central Processing Unit (hereinafter referred to as "CPU") 310 and a memory 320.

The CPU 310 functionally includes an operation control section 311, an injection valve control section 312, a first valve control section 313, and a pressure equalization valve control section 314.
That is, the CPU 310 functions as the operation control section 311, the injection valve control section 312, the first valve control section 313, and the pressure equalization valve control section 314 by operating based on a predetermined program.
Memory 320 stores various data acquired by control device 300.

The operation control unit 311 controls the operation of the refrigerator 1 based on a control command output from the indoor unit in response to an operation performed on the indoor unit side.
The operation control unit 311 controls the low stage compressor 23 and the high stage compressor 26 based on control commands output from the indoor unit.
The operation control unit 311 controls the operation of each part of the refrigerator 1, such as the

fans

242 and 32, based on control commands output from the indoor unit.

The injection valve control unit 312 controls the opening/closing operation of the injection valve 61 of the injection circuit 120.
For example, when the temperature inside the high-stage compressor 26 detected by a temperature sensor (not shown) exceeds a predetermined standard, the injection valve control unit 312 opens the injection valve 61 and controls the injection circuit 120. Injection of refrigerant into the high-stage compressor 26 is performed through the high-stage compressor 26.

The first valve control unit 313 controls the opening/closing operation of the first valve 511 of the first circuit 510.
The first valve control unit 313 opens the first valve 511 to equalize the pressures of the high pressure pipe 100H and the low pressure pipe 100L via the first circuit 510.
The pressure equalization valve control unit 314 controls the opening and closing operations of the pressure equalization valve 521 of the pressure equalization circuit 520.
The pressure equalization valve control unit 314 equalizes the pressure between the first circuit 510 and the intermediate pressure pipe 100M via the pressure equalization circuit 520 by opening the pressure equalization valve 521.

(Steps for controlling the refrigerator)
As shown in FIG. 4, the method S10 for controlling the refrigerator 1 according to the embodiment of the present disclosure includes step S11 of opening the first valve 511 of the first circuit 510, and step S12 of opening the pressure equalizing valve 521 of the pressure equalizing circuit 520. and, including.
As shown in FIG. 5, during normal operation of the refrigerator 1, refrigerant flows from the low-pressure pipe 100L to the low-stage compressor 23, the medium-pressure pipe 100M, the high-stage compressor 26, and the high-pressure pipe 100H to the eleventh pipe. It is sent to the indoor unit through 111.
In this embodiment, the method S10 for controlling the refrigerator 1 is automatically executed when the operation of the low stage compressor 23 and the high stage compressor 26 is stopped.
In step S11 of opening the first valve 511 of the first circuit 510, the first valve 511 of the first circuit 510 is opened under the control of the first valve control section 313. Then, as shown in FIG. 6, the high-pressure pipe 100H and the low-pressure pipe 100L communicate with each other through the first circuit 510 extending from the high-pressure pipe 100H to the low-pressure pipe 100L. Thereby, the pressures of the high pressure pipe 100H and the low pressure pipe 100L are equalized.
In step S12 of opening the pressure equalizing valve 521 of the pressure equalizing circuit 520, the pressure equalizing valve 521 of the pressure equalizing circuit 520 is opened under the control of the pressure equalizing valve control section 314. At this time, if the injection valve 61 is not open, the injection valve 61 is opened under the control of the injection valve control section 312. Thereby, the first circuit 510 and the medium pressure pipe 100M communicate with each other via the pressure equalization circuit 520. Thereby, the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L are equalized.

(effect)
In this embodiment, the refrigerator 1 includes a first circuit 510 extending from the high pressure pipe 100H to the low pressure pipe 100L, and a pressure equalizing circuit 520 that can equalize the pressure between the medium pressure pipe 100M. When the operation of the low-stage compressor 23 and the high-stage compressor 26 is stopped, when the first valve 511 provided in the first circuit 510 is opened, the pressures of the high-pressure pipe 100H and the low-pressure pipe 100L are equalized. Moreover, when the pressure equalization valve 521 provided in the pressure equalization circuit 520 is opened, the pressures of the first circuit 510 and the intermediate pressure pipe 100M are equalized. Thereby, the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L are equalized. In this way, in order to equalize the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L, the first circuit 510 including the first valve 511, the pressure equalizing circuit 520 including the pressure equalizing valve 521, All you have to do is prepare. Therefore, it is possible to provide the refrigerator 1 with a simple configuration and easy pressure equalization.

Furthermore, when the first circuit 510 of the refrigerator 1 is opened, the first circuit 510 supplies high-pressure refrigerant having a higher temperature than the low-pressure refrigerant to the low-pressure pipe 100L. Thereby, when the temperature of the refrigerant supplied from the low-pressure pipe 100L to the low-stage compressor 23 drops too much, the temperature of the refrigerant can be increased. Therefore, the efficiency when compressing the refrigerant in the low stage compressor 23 can be increased.

Further, in the refrigerator 1, by injecting a refrigerant with a low temperature into the high-stage compressor 26 via the injection circuit 120, the efficiency when compressing the refrigerant with the high-stage compressor 26 is increased. The pressure equalization circuit 520 connects the first circuit 510 and the injection circuit 120, so that the first circuit 510 equalizes the pressure of the high pressure pipe 100H and the low pressure pipe 100L, and the medium pressure pipe 100M through the injection circuit 120. The pressure can be equalized. In this way, by using the injection circuit 120 also for pressure equalization, the number of newly installed piping can be reduced.

Further, a pressure equalization circuit 520 connects the injection circuit 120 and a position 513 on the downstream side in the flow direction of the high-pressure refrigerant in the first circuit 510. The downstream position 513 in the flow direction of the high-pressure refrigerant in the first circuit 510 is a position close to the low-pressure pipe 100L. Therefore, at a position close to the low pressure pipe 100L in the first circuit 510, the pressures of the medium pressure pipe 100M and the low pressure pipe 100L can be equalized via the injection circuit 120.

In addition, the refrigerator 1 supplies the refrigerant through the injection circuit 120 to the refrigerant cooled by the intercooler 24 provided in the medium pressure pipe 100M. If the temperature drops too much, the temperature of the refrigerant can be increased. Therefore, the efficiency when compressing the refrigerant in the high-stage compressor 26 is increased.

Furthermore, in the refrigerator 1, the first circuit 510 includes a flow rate adjustment mechanism 512, so that when the first valve 511 is opened, the flow rate of high-pressure refrigerant flowing from the high-pressure pipe 100H side to the low-pressure pipe 100L side can be adjusted. I can do it.

Further, in the refrigerator 1, in the high-pressure pipe 100H, the downstream side of the oil separator 27 in the flow direction of the high-pressure refrigerant is a position where the pressure of the high-pressure refrigerant compressed by the high-stage compressor 26 is highest. In the low-pressure pipe 100L, the downstream side of the inlet accumulator 21 in the flow direction of the low-pressure refrigerant is a position immediately before the low-stage compressor 23, where the pressure of the low-pressure refrigerant is lowest. The first circuit 510 connects the downstream side of the oil separator 27 in the direction of flow of the high-pressure refrigerant, and the downstream side of the inlet accumulator 21 in the direction of flow of the low-pressure refrigerant in the low-pressure pipe 100L. Thereby, it is possible to efficiently equalize the pressure via the first circuit 510 between the position where the pressure of the high-pressure refrigerant is highest in the high-pressure pipe 100H and the position where the pressure of the low-pressure refrigerant is the lowest in the low-pressure pipe 100L. can.

Furthermore, the high-stage compressor 26 and the low-stage compressor 23 each include two

compression sections

231, 232, 261, and 262 in series. That is, the high-stage compressor 26 and the low-stage compressor 23 include a total of four stages of

compression sections

231, 232, 261, and 262. In such a configuration, it is possible to equalize the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L.

Furthermore, when the operation of the low-stage compressor 23 and the high-stage compressor 26 is stopped, the control device 300 of the refrigerator 1 opens the first valve 511 provided in the first circuit 510, and the high-pressure pipe 100H is opened. The pressure of the low pressure pipe 100L is equalized. Moreover, when the pressure equalization valve 521 provided in the pressure equalization circuit 520 is opened, the pressures of the first circuit 510 and the medium pressure pipe 100M are equalized. Thereby, the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L are equalized. In this way, in order to equalize the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L, the first circuit 510 including the first valve 511, the pressure equalizing circuit 520 including the pressure equalizing valve 521, All you have to do is prepare. Therefore, it is possible to provide the refrigerator 1 with a simple configuration and easy pressure equalization.

Furthermore, in the control method S10 of the refrigerator 1, when the operation of the low stage compressor 23 and the high stage compressor 26 is stopped, when the first valve 511 provided in the first circuit 510 is opened, the high pressure pipe 100H is opened. The pressure of the low pressure pipe 100L is equalized. Moreover, when the pressure equalization valve 521 provided in the pressure equalization circuit 520 is opened, the pressures of the first circuit 510 and the intermediate pressure pipe 100M are equalized. Thereby, the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L are equalized. In this way, in order to equalize the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L, the first circuit 510 including the first valve 511, the pressure equalizing circuit 520 including the pressure equalizing valve 521, All you have to do is prepare. Therefore, it is possible to provide the refrigerator 1 with a simple configuration and easy pressure equalization.

In addition, in the program, when the operation of the low-stage compressor 23 and the high-stage compressor 26 is stopped, when the first valve 511 provided in the first circuit 510 is opened, the high-pressure pipe 100H and the low-pressure pipe 100L are equalized. be pressured. Moreover, when the pressure equalization valve 521 provided in the pressure equalization circuit 520 is opened, the pressures of the first circuit 510 and the intermediate pressure pipe 100M are equalized. Thereby, the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L are equalized. In this way, in order to equalize the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L, the first circuit 510 including the first valve 511, the pressure equalizing circuit 520 including the pressure equalizing valve 521, All you have to do is prepare. Therefore, it is possible to provide the refrigerator 1 with a simple configuration and easy pressure equalization.

In the above-described embodiment, programs for realizing various functions of the control device 300 are recorded on a computer-readable recording medium, and the programs recorded on the recording medium are read into a computer system such as a microcomputer. , various processes are performed by executing. Here, various processes of the CPU of the computer system are stored in a computer-readable recording medium in the form of a program, and the various processes described above are performed by reading and executing this program by the computer. Further, the computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, and the like. Alternatively, this computer program may be distributed to a computer via a communication line, and the computer receiving the distribution may execute the program.

In the above-described embodiment, an example of the hardware configuration of a computer that executes programs for realizing various functions of the control device 300 will be described.

As shown in FIG. 7, the computer included in the control device 300 includes a CPU 310, a memory 320, a storage/playback device 330, an input/output interface (hereinafter referred to as "IO I/F") 340, and a communication interface ( (hereinafter referred to as "communication I/F") 350.

The memory 320 is a medium such as Random Access Memory (hereinafter referred to as "RAM") that temporarily stores data and the like used in programs executed by the control device 300.
The storage/reproduction device 330 is a device for storing data and the like in external media such as CD-ROM, DVD, and flash memory, and for reproducing data and the like from the external media.
The IO I/F 340 is an interface for inputting/outputting information between the control device 300 and other devices.
The communication I/F 350 is an interface that communicates with other devices via a communication line such as the Internet or a dedicated communication line.

(Other embodiments)
Although the embodiment of the present disclosure has been described above, this embodiment is shown as an example and is not intended to limit the scope of the present disclosure. This embodiment can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the present disclosure. This embodiment and its modifications are included within the scope and gist of the present disclosure, as well as within the scope of the present disclosure and its equivalents.

<Additional notes>
The refrigerator 1, the controller 300 for the refrigerator 1, the control method S10 for the refrigerator 1, and the program described in the embodiment are understood as follows, for example.

(1) The refrigerator 1 according to the first aspect includes a low-stage compressor 23 that compresses low-pressure refrigerant into medium-pressure refrigerant, a high-stage compressor 26 that compresses the medium-pressure refrigerant into high-pressure refrigerant, and the low-stage compressor 26 that compresses the medium-pressure refrigerant into high-pressure refrigerant. A low-pressure pipe 100L connected to the compressor 23 and through which the low-pressure refrigerant flows; an intermediate-pressure pipe 100M connected between the low-stage compressor 23 and the high-stage compressor 26 through which the medium-pressure refrigerant flows; A high-pressure pipe 100H connected to the high-stage compressor 26 and through which the high-pressure refrigerant flows, a first circuit 510 extending from the high-pressure pipe 100H to the low-pressure pipe 100L, and between the first circuit 510 and the medium-pressure pipe 100M. a pressure equalizing circuit 520 capable of equalizing the pressure, the first circuit 510 includes a first valve 511 that opens and closes a flow path in the first circuit 510, and the pressure equalizing circuit 520 A pressure equalizing valve 521 that opens and closes a flow path in the circuit 520 is provided.

This refrigerator 1 includes a first circuit 510 extending from the high pressure pipe 100H to the low pressure pipe 100L, and a pressure equalizing circuit 520 that can equalize the pressure between the medium pressure pipe 100M. When the operation of the low-stage compressor 23 and the high-stage compressor 26 is stopped, when the first valve 511 provided in the first circuit 510 is opened, the pressures of the high-pressure pipe 100H and the low-pressure pipe 100L are equalized. Moreover, when the pressure equalization valve 521 provided in the pressure equalization circuit 520 is opened, the pressures of the first circuit 510 and the intermediate pressure pipe 100M are equalized. Thereby, the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L are equalized. In this way, in order to equalize the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L, the first circuit 510 including the first valve 511, the pressure equalizing circuit 520 including the pressure equalizing valve 521, All you have to do is prepare. Therefore, it is possible to provide the refrigerator 1 with a simple configuration and easy pressure equalization.

(2) The refrigerator 1 according to the second aspect is the refrigerator 1 of (1), in which when the first circuit 510 opens the first valve 511, the flow flows through the high pressure pipe 100H, and the The high-pressure refrigerant, which has a higher temperature than the low-pressure refrigerant, is supplied to the low-pressure pipe 100L.

As a result, when the first circuit 510 is opened, the first circuit 510 supplies high-pressure refrigerant, which has a higher temperature than the low-pressure refrigerant, to the low-pressure pipe 100L. Thereby, when the temperature of the refrigerant supplied from the low-pressure pipe 100L to the low-stage compressor 23 drops too much, the temperature of the refrigerant can be increased. Therefore, the efficiency when compressing the refrigerant in the low stage compressor 23 can be increased.

(3) The refrigerator 1 according to the third aspect is the refrigerator 1 of (1) or (2), which is connected to the medium pressure pipe 100M, and is connected to the high stage compressor 26. The pressure equalizing circuit 520 is capable of connecting the first circuit 510 and the injection circuit 120.

Thereby, by injecting the refrigerant with a low temperature into the high-stage compressor 26 via the injection circuit 120, the efficiency when compressing the refrigerant in the high-stage compressor 26 is increased. The pressure equalization circuit 520 connects the first circuit 510 and the injection circuit 120, so that the first circuit 510 equalizes the pressure of the high pressure pipe 100H and the low pressure pipe 100L, and the medium pressure pipe 100M through the injection circuit 120. The pressure can be equalized. In this way, by using the injection circuit 120 also for pressure equalization, the number of newly installed piping can be reduced.

(4) The refrigerator 1 according to the fourth aspect is the refrigerator 1 according to (3), in which the pressure equalization circuit 520 is connected to the injection circuit 120 and the first circuit 510. 513 on the downstream side in the flow direction of the high-pressure refrigerant.

In this way, the pressure equalization circuit 520 connects the injection circuit 120 and the position 513 on the downstream side in the flow direction of the high-pressure refrigerant in the first circuit 510. The downstream position 513 in the flow direction of the high-pressure refrigerant in the first circuit 510 is a position close to the low-pressure pipe 100L. Therefore, at a position close to the low pressure pipe 100L in the first circuit 510, the pressures of the medium pressure pipe 100M and the low pressure pipe 100L can be equalized via the injection circuit 120.

(5) The refrigerator 1 according to the fifth aspect is the refrigerator 1 of (3) or (4), which is disposed in the middle of the medium pressure pipe 100M and compressed by the low stage compressor 23. The injection circuit 120 includes an intercooler 24 that cools the medium-pressure refrigerant, and the injection circuit 120 is connected between the intercooler 24 and the high-stage compressor 26 with respect to the medium-pressure pipe 100M.

As a result, by sending the refrigerant through the injection circuit 120 to the refrigerant cooled by the intercooler 24 provided in the medium pressure pipe 100M, the temperature of the refrigerant decreases too much by being cooled by the intercooler 24, for example. In this case, the temperature of the refrigerant can be increased. Therefore, the efficiency when compressing the refrigerant in the high-stage compressor 26 is increased.

(6) The refrigerator 1 according to the sixth aspect is the refrigerator 1 according to any one of (1) to (5), and when the first circuit 510 opens the first valve 511, A flow rate adjustment mechanism 512 that adjusts the flow rate of the high-pressure refrigerant is provided.

Accordingly, since the first circuit 510 includes the flow rate adjustment mechanism 512, when the first valve 511 is opened, the flow rate of the high-pressure refrigerant flowing from the high-pressure pipe 100H side to the low-pressure pipe 100L side can be adjusted.

(7) The refrigerator 1 according to the seventh aspect is the refrigerator 1 according to any one of (1) to (6), in which the low-pressure refrigerant supplied to the low-stage compressor 23 is replaced with a gas refrigerant. The first circuit 510 includes an accumulator 21 that separates oil from liquid refrigerant, and an oil separator 27 that separates oil contained in the high-pressure refrigerant discharged from the high-stage compressor 26. , the oil separator 27 is connected to the downstream side in the direction of flow of the high-pressure refrigerant, and the accumulator 21 is connected to the downstream side in the direction of flow of the low-pressure refrigerant in the low-pressure pipe 100L.

In the high-pressure pipe 100H, the downstream side of the oil separator 27 in the flow direction of the high-pressure refrigerant is a position where the pressure of the high-pressure refrigerant compressed by the high-stage compressor 26 is highest. In the low-pressure pipe 100L, the downstream side of the accumulator 21 in the flow direction of the low-pressure refrigerant is a position immediately before the low-stage compressor 23, where the pressure of the low-pressure refrigerant is lowest. The first circuit 510 connects the downstream side of the oil separator 27 in the direction of flow of high-pressure refrigerant, and the downstream side of the accumulator 21 in the direction of flow of low-pressure refrigerant in the low-pressure pipe 100L. This makes it possible to efficiently equalize the pressure via the first circuit 510 between the position where the pressure of the high-pressure refrigerant is highest in the high-pressure pipe 100H and the position where the pressure of the low-pressure refrigerant is the lowest in the low-pressure pipe 100L. can.

(8) The refrigerator 1 according to the eighth aspect is the refrigerator 1 according to any one of (1) to (7), in which the high stage compressor 26 and the low stage compressor 23 are each , is a two-stage compressor equipped with two

compression sections

231, 232, 261, and 262 in series.

Thereby, the high-stage compressor 26 and the low-stage compressor 23 each include two

compression sections

(9) The control device 300 for the refrigerator 1 according to the ninth aspect includes a low-stage compressor 23 that compresses a low-pressure refrigerant into an intermediate-pressure refrigerant, and a high-stage compressor 26 that compresses the intermediate-pressure refrigerant into a high-pressure refrigerant. , a low-pressure pipe 100L connected to the low-stage compressor 23 and through which the low-pressure refrigerant flows; and an intermediate-pressure pipe connected between the low-stage compressor 23 and the high-stage compressor 26 and through which the medium-pressure refrigerant flows. 100M, and a high-pressure pipe 100H connected to the high-stage compressor 26 and through which the high-pressure refrigerant flows, a first circuit 510 that is capable of controlling the refrigerator 1 and extends to the high-pressure pipe 100H and the low-pressure pipe 100L. a first valve control unit 313 that opens a first valve 511; and a pressure equalization valve control unit 314 that opens a pressure equalization valve 521 of a pressure equalization circuit 520 that can equalize the pressure between the first circuit 510 and the medium pressure pipe 100M. , is provided.

As a result, when the operation of the low-stage compressor 23 and the high-stage compressor 26 is stopped, opening the first valve 511 provided in the first circuit 510 equalizes the pressure in the high-pressure pipe 100H and the low-pressure pipe 100L. Ru. Moreover, when the pressure equalization valve 521 provided in the pressure equalization circuit 520 is opened, the pressures of the first circuit 510 and the intermediate pressure pipe 100M are equalized. Thereby, the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L are equalized. In this way, in order to equalize the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L, the first circuit 510 including the first valve 511, the pressure equalizing circuit 520 including the pressure equalizing valve 521, All you have to do is prepare. Therefore, it is possible to provide the refrigerator 1 with a simple configuration and easy pressure equalization.

(10) The control method S10 for the refrigerator 1 according to the tenth aspect includes a low-stage compressor 23 that compresses a low-pressure refrigerant into an intermediate-pressure refrigerant, and a high-stage compressor 26 that compresses the intermediate-pressure refrigerant into a high-pressure refrigerant. , a low-pressure pipe 100L connected to the low-stage compressor 23 and through which the low-pressure refrigerant flows; and an intermediate-pressure pipe connected between the low-stage compressor 23 and the high-stage compressor 26 and through which the medium-pressure refrigerant flows. 100M, and a high-pressure pipe 100H connected to the high-stage compressor 26 and through which the high-pressure refrigerant flows. a step S11 of opening the first valve 511 of the first circuit 510 extending to the high-pressure pipe 100H and the low-pressure pipe 100L, and opening the first valve 511 between the first circuit 510 and the medium-pressure pipe 100M when the operation of Step S12 of opening the pressure equalizing valve 521 of the pressure equalizing circuit 520 capable of equalizing the pressure.

(11) The program according to the eleventh aspect includes: a low-stage compressor 23 that compresses low-pressure refrigerant into medium-pressure refrigerant; a high-stage compressor 26 that compresses the medium-pressure refrigerant into high-pressure refrigerant; 23, through which the low-pressure refrigerant flows; an intermediate-pressure pipe 100M, which is connected between the low-stage compressor 23 and the high-stage compressor 26, through which the medium-pressure refrigerant flows; When the operation of the low-stage compressor 23 and the high-stage compressor 26 is stopped, the control device 300 of the refrigerator 1 includes a high-pressure pipe 100H connected to the compressor 26 and through which the high-pressure refrigerant flows. , opening a first valve 511 of a first circuit 510 extending to the high pressure pipe 100H and the low pressure pipe 100L; and a pressure equalizing circuit 520 capable of equalizing the pressure between the first circuit 510 and the medium pressure pipe 100M. A control including a step of opening the pressure equalizing valve 521 is executed.

In this program, when the operation of the low stage compressor 23 and the high stage compressor 26 is stopped, when the first valve 511 provided in the first circuit 510 is opened, the high pressure pipe 100H and the low pressure pipe 100L are equalized in pressure. be done. Moreover, when the pressure equalization valve 521 provided in the pressure equalization circuit 520 is opened, the pressures of the first circuit 510 and the intermediate pressure pipe 100M are equalized. Thereby, the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L are equalized. In this way, in order to equalize the pressures of the high pressure pipe 100H, the medium pressure pipe 100M, and the low pressure pipe 100L, the first circuit 510 including the first valve 511, the pressure equalizing circuit 520 including the pressure equalizing valve 521, All you have to do is prepare. Therefore, it is possible to provide the refrigerator 1 with a simple configuration and easy pressure equalization.

1... Refrigerator 2... Compression section 3... Condenser 4... Expansion valve 5... Receiver 6... Supercooling heat exchanger 21... Inlet accumulator (accumulator)
22...Subaccumulator 23...Low stage compressor 24...Intercooler 25...Intermediate accumulator 26...High stage compressor 27...Oil separator 28...Oil tank 29...Oil cooler 31...Condenser body 32...Fan 61...Injection valve 62... Expansion valve for supercooling heat exchanger 100L...Low pressure pipe 100M...Medium pressure pipe 100H...High pressure pipe 101...First pipe 102...Second pipe 103...Third pipe 104...Fourth pipe 105...Fifth pipe 106...Sixth pipe 107...Seventh pipe 108...Eighth pipe 109...Ninth pipe 110...Tenth pipe 111...Eleventh pipe 112...Twelfth pipe 120...Injection circuit 231...First rotary compression section (compression section)
232...First scroll compression section (compression section)
241...Intercooler main body 242...Fan 261...Second rotary compression section (compression section)
262...Second scroll compression section (compression section)
300...control device 310...CPU
311...Operation control section 312...Injection valve control section 313...First valve control section 314...Pressure equalization valve control section 320...Memory 330...Storage/reproduction device 340...IO I/F
350...Communication I/F
401...First oil return pipe 402...Second oil return pipe 403...Third oil return pipe 404...Fourth oil return pipe 405...Fifth oil return pipe 500...Pressure equalization mechanism 510...First circuit 510a...One end 510b... Other end 511...First valve 512...Flow rate adjustment mechanism 520...Pressure equalization circuit 520a...One end 520b...Other end 521...Pressure equalization valve S10...Refrigerating machine control method S11...Step of opening the first valve of the first circuit S12...Equilibrium Step of opening the pressure equalization valve in the pressure circuit

Claims

a low-stage compressor that compresses low-pressure refrigerant into medium-pressure refrigerant;
a high-stage compressor that compresses the medium-pressure refrigerant into high-pressure refrigerant;
a low-pressure pipe connected to the low-stage compressor and through which the low-pressure refrigerant flows;
an intermediate pressure pipe connected between the low stage compressor and the high stage compressor, through which the intermediate pressure refrigerant flows;
a high-pressure pipe connected to the high-stage compressor and through which the high-pressure refrigerant flows;
a first circuit extending from the high pressure piping to the low pressure piping;
a pressure equalizing circuit capable of equalizing the pressure between the first circuit and the medium pressure piping;
The first circuit includes a first valve that opens and closes a flow path in the first circuit,
The said pressure equalization circuit is equipped with the pressure equalization valve which opens and closes the flow path in the said pressure equalization circuit. Refrigerator.
The refrigerator according to claim 1, wherein the first circuit supplies the high-pressure refrigerant, which flows through the high-pressure pipe and has a higher temperature than the low-pressure refrigerant, to the low-pressure pipe when the first valve is opened.
an injection circuit connected to the intermediate pressure piping and injecting refrigerant having a temperature lower than that of the refrigerant in the high-stage compressor into the high-stage compressor;
The refrigerator according to claim 1 or 2, wherein the pressure equalization circuit is capable of connecting the first circuit and the injection circuit.
The refrigerator according to claim 3, wherein the pressure equalization circuit connects the injection circuit to a downstream position in the first circuit in the flow direction of the high-pressure refrigerant.
an intercooler disposed in the middle of the medium pressure piping and cooling the medium pressure refrigerant compressed by the low stage compressor;
The refrigerator according to claim 3, wherein the injection circuit is connected to the intermediate pressure pipe between the intercooler and the high-stage compressor.
The refrigerator according to claim 1 or 2, wherein the first circuit includes a flow rate adjustment mechanism that adjusts the flow rate of the high-pressure refrigerant when the first valve is opened.
an accumulator that separates the low-pressure refrigerant supplied to the low-stage compressor into a gas refrigerant and a liquid refrigerant;
an oil separator that separates oil contained in the high-pressure refrigerant discharged from the high-stage compressor,
The first circuit connects a downstream side of the high-pressure refrigerant in the flow direction of the high-pressure refrigerant to the oil separator in the high-pressure piping, and a downstream side of the low-pressure refrigerant in the flow direction of the accumulator in the low-pressure piping. The refrigerator according to claim 1 or 2.
The refrigerator according to claim 1 or 2, wherein the high-stage compressor and the low-stage compressor are each two-stage compressors including two compression sections in series.
a low-stage compressor that compresses low-pressure refrigerant into medium-pressure refrigerant;
a high-stage compressor that compresses the medium-pressure refrigerant into high-pressure refrigerant;
a low-pressure pipe connected to the low-stage compressor and through which the low-pressure refrigerant flows;
an intermediate pressure pipe connected between the low stage compressor and the high stage compressor, through which the intermediate pressure refrigerant flows;
a high-pressure pipe connected to the high-stage compressor and through which the high-pressure refrigerant flows;
A refrigerator comprising:
a first valve control unit that opens a first valve of a first circuit extending to the high pressure pipe and the low pressure pipe;
a pressure equalizing valve control unit that opens a pressure equalizing valve of a pressure equalizing circuit capable of equalizing the pressure between the first circuit and the medium pressure pipe;
A refrigerator control device.
a low-stage compressor that compresses low-pressure refrigerant into medium-pressure refrigerant;
a high-stage compressor that compresses the medium-pressure refrigerant into high-pressure refrigerant;
a low-pressure pipe connected to the low-stage compressor and through which the low-pressure refrigerant flows;
an intermediate pressure pipe connected between the low stage compressor and the high stage compressor, through which the intermediate pressure refrigerant flows;
a high-pressure pipe connected to the high-stage compressor and through which the high-pressure refrigerant flows;
A method for controlling a refrigerator, comprising:
opening a first valve of a first circuit extending to the high pressure pipe and the low pressure pipe when the operation of the low stage compressor and the high stage compressor is stopped;
opening a pressure equalizing valve of a pressure equalizing circuit capable of equalizing the pressure between the first circuit and the medium pressure pipe;
Including how to control a refrigerator.
a low-stage compressor that compresses low-pressure refrigerant into medium-pressure refrigerant;
a high-stage compressor that compresses the medium-pressure refrigerant into high-pressure refrigerant;
a low-pressure pipe connected to the low-stage compressor and through which the low-pressure refrigerant flows;
an intermediate pressure pipe connected between the low stage compressor and the high stage compressor, through which the intermediate pressure refrigerant flows;
a high-pressure pipe connected to the high-stage compressor and through which the high-pressure refrigerant flows;
A refrigerator control device equipped with
opening a first valve of a first circuit extending to the high pressure pipe and the low pressure pipe when the operation of the low stage compressor and the high stage compressor is stopped;
opening a pressure equalizing valve of a pressure equalizing circuit capable of equalizing the pressure between the first circuit and the medium pressure pipe;
A program that executes control including.