WO2020164215A1

WO2020164215A1 - Refrigerant circulation system and air conditioner

Info

Publication number: WO2020164215A1
Application number: PCT/CN2019/092501
Authority: WO
Inventors: 苏玉海; 熊建国; 张仕强; 李立民
Original assignee: 珠海格力电器股份有限公司
Priority date: 2019-02-12
Filing date: 2019-06-24
Publication date: 2020-08-20
Also published as: CN109682104B; CN109682104A

Abstract

A refrigerant circulation system and an air conditioner. The refrigerant circulation system comprises a first centrifugal compressor (1), a second centrifugal compressor (2) connected in series with the first centrifugal compressor (1), a first heat exchanger (5) communicated with the second centrifugal compressor (2) and used for allowing a compressed refrigerant to condense and release heat in the first heat exchanger (5), and second heat exchangers (13) communicated with the first heat exchanger (5) and used for allowing the condensed refrigerant to evaporate and absorb heat in the second heat exchangers. The air conditioner comprises the refrigerant circulation system. The refrigerant circulation system improves the cooling or heating effect of the air conditioner.

Description

Refrigerant circulation system and air conditioner

The present disclosure is based on the application with the CN application number CN201910111065.6 and the filing date of February 12, 2019, and claims its priority. The disclosure of the CN application is hereby incorporated into the present disclosure as a whole.

Technical field

The present disclosure relates to the technical field of air conditioners, and in particular to a refrigerant circulation system and an air conditioner.

Background technique

The use of a centrifugal compressor multi-line air-conditioning system can eliminate the need for lubricating oil, can remove the oil return pipeline, simplify the structure, and improve the reliability of the entire machine. The disadvantage of centrifugal compressors is that the pressure ratio (the ratio of the compressor's discharge pressure to the suction pressure) is too low, resulting in insignificant air conditioning cooling/heating effects. At the same time, the low-temperature heating decay common in multi-line systems, compression The temperature rise of the machine motor also needs to be solved. The multi-line air conditioning system using a single-stage centrifugal compressor has the following disadvantages:

Single-stage centrifugal compressors have a low pressure ratio for the refrigerant to be compressed. Centrifugal compressors can achieve a pressure ratio n≤4 in single-stage compression. If the pressure ratio is too small, the cooling/heating effect of air conditioning is not obvious.

The function of the air-conditioning system for heating at low temperatures is attenuated. In a low temperature environment, the refrigerant evaporation pressure in the heat exchanger of the heat pump unit (including the centrifugal compressor and the heat exchanger for refrigerant evaporation) decreases, which causes the compressor suction specific volume to increase, the refrigerant flow rate decreases, and the compressor The effective volume is not fully utilized, and the heating capacity of the unit is greatly reduced.

The motor temperature of the centrifugal compressor increases. The motor temperature rises greatly during the compressor operation. If it is not cooled, it will not only consume more work, but also the exhaust temperature will be too high, which will be unfavorable to the compressor bearings, casing and other parts and affect the normal service life of the compressor.

Summary of the invention

The present disclosure aims to provide a refrigerant circulation system and an air conditioner to improve the problem of poor cooling or heating effect of the air conditioner in the related art.

According to one aspect of the embodiments of the present disclosure, the present disclosure provides a refrigerant circulation system, including:

The first centrifugal compressor;

The second centrifugal compressor is connected in series with the first centrifugal compressor;

A first heat exchanger; communicating with the second centrifugal compressor for the compressed refrigerant to condense and release heat therein; and

The second heat exchanger is in communication with the first heat exchanger, and is used for the condensed refrigerant to evaporate and absorb heat in it.

In some embodiments,

The first centrifugal compressor includes a first-stage centrifugal compression part and a second-stage centrifugal compression part for compressing the refrigerant compressed by the first-stage centrifugal compression part; and/or

The second centrifugal compressor includes a first-stage centrifugal compression part and a second-stage centrifugal compression part for compressing the refrigerant compressed by the first-stage centrifugal compression part.

In some embodiments, the refrigerant circulation system further includes a cooling pipeline for delivering refrigerant to the first centrifugal compressor and/or the second centrifugal compressor.

In some embodiments,

The inlet of the cooling pipeline is in communication with the outlet of the first heat exchanger; and/or

The outlet of the cooling pipeline is used for the refrigerant delivered to the motor of the first centrifugal compressor and/or the second centrifugal compressor.

In some embodiments, the refrigerant circulation system further includes a subcooler, and the subcooler includes:

The first inlet is connected with the outlet of the first heat exchanger and is used to introduce the refrigerant to be supercooled;

The first outlet is in communication with the inlet of the second heat exchanger and is used to output the supercooled refrigerant; and

The second outlet is in communication with the cooling pipeline and is used to deliver the refrigerant after heat exchange with the refrigerant to be supercooled to the cooling pipeline.

In some embodiments, the subcooler further includes:

The third heat exchanger is in communication with both the first inlet and the first outlet; and

The fourth heat exchanger communicates with the second outlet and is used to circulate the refrigerant that exchanges heat with the first heat exchanger.

In some embodiments, the refrigerant circulation system further includes a throttle component, the inlet of the throttle component is in communication with the first heat exchanger, and the outlet of the throttle component is in communication with the fourth heat exchanger.

In some embodiments, the refrigerant circulation system further includes:

The first pipeline is used to connect the first heat exchanger and the second heat exchanger, and is used to install the first heat exchanger thereon;

The second pipeline is used to connect the first pipeline and the fourth heat exchanger,

Wherein, the second pipeline is connected upstream or downstream of the first heat exchanger of the first pipeline.

In some embodiments, the refrigerant circulation system further includes means for conveying the refrigerant after cooling the first centrifugal compressor and/or the second centrifugal compressor to the suction port of the first centrifugal compressor or the second centrifugal compressor Return line.

In some embodiments, the refrigerant circulation system further includes a gas-liquid separator, the inlet of the gas-liquid separator is in communication with the return line, and the outlet of the hydraulic separator is in communication with the suction port of the first centrifugal compressor or the second centrifugal compressor .

According to another aspect of the present disclosure, there is provided an air conditioner including the above-mentioned refrigerant circulation system.

In some embodiments, the air conditioner includes a plurality of indoor heat exchangers, and each indoor heat exchanger is provided with a first heat exchanger or a second heat exchanger.

Applying the technical solution of the present disclosure, the refrigerant circulation system includes a first centrifugal compressor and a second centrifugal compressor connected in series, which improves the problem of poor cooling or heating effect of the air conditioner in the related art.

Description of the drawings

The drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure, and the exemplary embodiments and descriptions of the present disclosure are used to explain the present disclosure, and do not constitute an improper limitation of the present disclosure. In the attached picture:

Fig. 1 shows a schematic diagram of a refrigerant circulation system according to an embodiment of the present disclosure.

detailed description

In order to make the objectives, technical solutions, and advantages of the present disclosure clearer, the following further describes the present disclosure in detail with reference to the embodiments and the drawings. Here, the exemplary embodiments and descriptions of the present disclosure are used to explain the present disclosure, but are not intended to limit the present disclosure.

Fig. 1 shows a schematic diagram of the refrigerant circulation system of this embodiment. As shown in Fig. 1, the refrigerant circulation system of this embodiment includes a first centrifugal compressor 1, a second centrifugal compressor 2 for compressing refrigerant compressed by the first centrifugal compressor 1, and a refrigerant condensing therein. The first heat exchanger 5 and the second heat exchanger 13 for the refrigerant to evaporate therein.

The refrigerant circulation system of this embodiment includes a first centrifugal compressor 1 and a second centrifugal compressor 2 connected in series with the first centrifugal compressor 1. The refrigerant compressed by the first centrifugal compressor 1 is again by the second centrifugal compressor 2 Compression, so the problem of too low ratio of discharge pressure to suction pressure of single-stage centrifugal compressor is improved. It is also beneficial to improve the problem of poor cooling or heating effect of the air conditioner. The heating capacity of the air conditioner under low temperature conditions has also been improved.

In some embodiments, the first centrifugal compressor 1 includes a first-stage centrifugal compression part and a second-stage centrifugal compression part for compressing the refrigerant compressed by the first-stage centrifugal compression part. Wherein, the first centrifugal compression part includes a first impeller for accelerating the refrigerant to be compressed and a first diffuser for compressing the accelerated refrigerant therein. Wherein, the second centrifugal compression part includes a second impeller for accelerating the refrigerant compressed by the first centrifugal compression part and a second diffuser for compressing the accelerated refrigerant therein.

In some embodiments, the second centrifugal compressor 2 includes a first-stage centrifugal compression part and a second-stage centrifugal compression part for compressing the refrigerant compressed by the first-stage centrifugal compression part. Wherein, the first centrifugal compression part includes a first impeller for accelerating the refrigerant to be compressed and a first diffuser for compressing the accelerated refrigerant therein. Among them, the second centrifugal compression part includes a second impeller for accelerating the refrigerant compressed by the first centrifugal compression part and a second diffuser for compressing the accelerated refrigerant therein.

The refrigerant circulation system also includes a reversing valve 4, which includes an inlet communicating with the exhaust port of the second centrifugal compressor 2, an outlet communicating with the suction port of the first centrifugal compressor 1, and the first heat exchange valve. The first working port communicated with the device 5 and the second working port communicated with the second heat exchanger 13. The reversing valve 4 has a first state and a second state. In the first state, the inlet is connected to the first working port, and the second working port is connected to the outlet; in the second state, the inlet is connected to the second working port, The first working port is connected to the outlet. Preferably, the reversing valve 4 is a system valve.

When the reversing valve is in the first state, the refrigerant circulation system is in the first working condition, and the compressed refrigerant flows to the first heat exchanger 5 through the inlet and the first working port of the reversing valve 4, and the refrigerant is in the first heat exchanger 5. The internal condensation releases heat and flows to the second heat exchanger 13 through the first throttling part 6. The refrigerant evaporates and absorbs heat in the second heat exchanger 13 and flows to the first centrifugal compression through the second working port and outlet of the reversing valve 4 The suction port of machine 1.

When the reversing valve is in the second state, the refrigerant circulation system is in the second working condition, and the compressed refrigerant flows to the second heat exchanger 13 through the inlet and the second working port of the reversing valve 4, and the refrigerant is in the second heat exchanger 13 After the internal condensation releases heat, it flows to the first heat exchanger 5 through the first throttling part 6. The refrigerant evaporates and absorbs heat in the first heat exchanger 5 and flows to the first centrifugal compression through the first working port and outlet of the reversing valve 4 The suction port of machine 1.

The refrigerant circulation system further includes a gas-liquid separator 14 connected between the outlet of the reversing valve 4 and the first centrifugal compressor 1.

The refrigerant circulation system further includes a cooling pipe 3 for conveying refrigerant to the first centrifugal compressor 1 and/or the second centrifugal compressor 2.

The inlet of the cooling pipe 3 is in communication with the first pipe 8 between the first heat exchanger 5 and the second heat exchanger 13, and the outlet of the cooling pipe 3 is used to feed the first centrifugal compressor 1 and/or the second centrifugal compressor 1 The refrigerant delivered by the motor of the compressor 2.

The refrigerant circulation system also includes a subcooler 7, which includes a first inlet communicating with the first heat exchanger 5 and a first outlet communicating with the second heat exchanger 13, connecting the first inlet and the first outlet. The third heat exchanger 9, the second inlet for introducing the refrigerant exchanged with the third heat exchanger 9 and the second outlet for outputting the refrigerant after heat exchange with the third heat exchanger 9, the second outlet Connect with the cooling pipe 3.

The subcooler 7 also includes a second heat exchanger 10 connected between the second inlet and the second outlet. The refrigerant circulation system further includes a second throttling component 11, the inlet of the second throttling component 11 is in communication with the first heat exchanger 5, and the outlet of the throttling component 11 is in communication with the fourth heat exchanger 10.

The refrigerant circulation system further includes a second pipeline 15 for connecting the second inlet of the cooler 7 and the first pipeline 8, and the second throttling component 11 is arranged in the second pipeline 15.

The second pipeline 15 introduces a part of the refrigerant in the first pipeline 8 into the fourth heat exchanger 10. Since the second pipeline 15 is provided with a throttling component 11, the refrigerant introduced by the second pipeline 15 is throttled and reduced in pressure Then it is evaporated in the fourth heat exchanger 10 to lower the temperature of the refrigerant in the third heat exchanger 9. The refrigerant evaporated in the fourth heat exchanger 10 is sent to the first centrifugal compressor 1 and the first centrifugal compressor through the cooling pipe 3 The inside of the second centrifugal compressor 2 cools the motors of the first centrifugal compressor 1 and the second centrifugal compressor.

The refrigerant circulation system also includes a first branch for connecting the inner cavity of the first centrifugal compressor 1 and the cooling pipe 3 and a second branch for connecting the inner cavity of the second centrifugal compressor 2 and the cooling pipe 3 . There is a first valve in the first branch. A second valve is provided in the second branch. Optionally, the first valve and/or the second valve are regulating valves to distribute the refrigerant according to the specific conditions of the two compressors.

The refrigerant circulation system further includes a return line for conveying the refrigerant after cooling the first centrifugal compressor and/or the second centrifugal compressor to the suction port of the first centrifugal compressor 1. Optionally, the return line is in communication with the gas-liquid separator 14.

The refrigerant circulation system includes a plurality of second heat exchangers 13 and a plurality of third throttling members 12 arranged in one-to-one correspondence with the second heat exchangers 13.

According to another aspect of the present disclosure, there is also provided an air conditioner including the above-mentioned refrigerant circulation system.

The air conditioner is a multi-line air conditioning system. The air conditioner includes a plurality of indoor units, and each indoor unit is provided with a second heat exchanger 13.

When the air conditioner is in the refrigeration mode, the refrigerant compressed from the first centrifugal compressor 1 enters the second centrifugal compressor 2 for further compression. According to actual requirements, multiple centrifugal compressors in series can be provided. Multiple compressions can effectively increase the pressure ratio and obtain high temperature and high pressure gaseous refrigerant.

The high-temperature and high-pressure gaseous refrigerant enters the outdoor heat exchanger to release heat and condenses into a liquid refrigerant. The liquid refrigerant flow is divided into two paths when passing through the cooler, and a small part of the refrigerant is separated out, and after passing through the electronic second throttling component 11, it exchanges heat with the main path refrigerant to provide a degree of subcooling.

After the branch refrigerant subcools the main refrigerant, it is sprayed into the motor part of the centrifugal compressor to cool it, and then enters the gas-liquid separator 12. The main circuit refrigerant enters the indoor unit after being supercooled, and is throttled and reduced by the electronic expansion valve to obtain a low-temperature and low-pressure liquid refrigerant, which evaporates and absorbs heat in the indoor heat exchanger to achieve cooling. After being evaporated into gaseous refrigerant, it passes through vapor separation to separate part of the liquid refrigerant, and the gaseous refrigerant enters the compressor to form a cycle.

Compared with the cooling mode, the heating mode of the air conditioner needs to switch the four-way valve, so that after the refrigerant comes out of the compressor, it will first pass through the indoor heat exchanger to release heat, then throttling into the outdoor heat exchanger to absorb heat, and finally return to compression machine. Other functions are the same as refrigeration.

The refrigerant circulation system of the present disclosure adopts multi-stage compression, which can increase the compression ratio of the system and control it within a reasonable range, improve the volumetric efficiency of the compressor, and at the same time increase the capacity of the whole machine.

Furthermore, the low-temperature refrigerant is used to cool the motor, to prevent the motor from being damaged due to excessive temperature rise, and to improve the normal service life of the compressor.

The foregoing descriptions are only preferred embodiments of the present disclosure and are not intended to limit the present disclosure. For those skilled in the art, the embodiments of the present disclosure may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

A refrigerant circulation system, including:

The first centrifugal compressor (1);

The second centrifugal compressor (2) is connected in series with the first centrifugal compressor (1);

A first heat exchanger (5); communicating with the second centrifugal compressor (2) for the compressed refrigerant to condense and release heat therein; and

The second heat exchanger (13) is in communication with the first heat exchanger (5), and is used for evaporating and absorbing heat of the condensed refrigerant in it.
The refrigerant circulation system according to claim 1, wherein:

The first centrifugal compressor (1) includes a first-stage centrifugal compression part and a second-stage centrifugal compression part for compressing the refrigerant compressed by the first-stage centrifugal compression part; and/or

The second centrifugal compressor (2) includes a first-stage centrifugal compression part and a second-stage centrifugal compression part for compressing the refrigerant compressed by the first-stage centrifugal compression part.
The refrigerant circulation system according to claim 1, further comprising a cooling pipe (3) for conveying refrigerant to the first centrifugal compressor (1) and/or the second centrifugal compressor (2).
The refrigerant circulation system according to claim 3, wherein:

The inlet of the cooling pipeline (3) is in communication with the outlet of the first heat exchanger (5); and/or

The outlet of the cooling pipeline (3) is used for the refrigerant delivered to the motor of the first centrifugal compressor (1) and/or the second centrifugal compressor (2).
The refrigerant circulation system according to claim 3, further comprising a supercooler (7), the supercooler (7) comprising:

The first inlet is in communication with the outlet of the first heat exchanger (5), and is used to introduce the refrigerant to be supercooled;

The first outlet is in communication with the inlet of the second heat exchanger (13), and is used to output the supercooled refrigerant; and

The second outlet is in communication with the cooling pipe (3), and is used to deliver the refrigerant after heat exchange with the refrigerant to be supercooled to the cooling pipe (3).
The refrigerant circulation system according to claim 5, wherein the supercooler (7) further comprises:

The third heat exchanger (9) is in communication with both the first inlet and the first outlet; and

The fourth heat exchanger (10) communicates with the second outlet and is used to circulate the refrigerant that exchanges heat with the first heat exchanger (9).
The refrigerant circulation system according to claim 6, further comprising a throttle component (11), the inlet of the throttle component (11) is in communication with the first heat exchanger (5), and the throttle component (11) ) Is in communication with the fourth heat exchanger (10).
The refrigerant circulation system according to claim 6, further comprising:

The first pipeline (8) is used to connect the first heat exchanger (5) and the second heat exchanger (13), and is used to install the first heat exchanger (9) thereon;

The second pipeline (15) is used to connect the first pipeline (8) and the fourth heat exchanger (10),

Wherein, the second pipeline (15) is connected to the upstream or downstream of the first heat exchanger (9) of the first pipeline (8).
The refrigerant circulation system according to claim 3, further comprising means for transporting the refrigerant after cooling the first centrifugal compressor (1) and/or the second centrifugal compressor (2) to the first centrifugal compressor ( 1) Or the return line of the suction port of the second centrifugal compressor (2).
The refrigerant circulation system according to claim 9, further comprising a gas-liquid separator (14), the inlet of the gas-liquid separator (14) is in communication with the return line, and the outlet of the hydraulic separator (14) It is connected with the suction port of the first centrifugal compressor (1) or the second centrifugal compressor (2).
An air conditioner, comprising the refrigerant circulation system according to claim 1.
The refrigerant circulation system according to claim 11, wherein the air conditioner includes a plurality of indoor heat exchangers, and each of the indoor heat exchangers is provided with a first heat exchanger (5) or a second heat exchanger (13).