CN218442540U

CN218442540U - Multi-split heat exchange unit and multi-split air conditioner

Info

Publication number: CN218442540U
Application number: CN202221920758.3U
Authority: CN
Inventors: 宋德跃; 罗建文; 孙鹏龙; 周福艳; 修侃; 李�根; 王永帅
Original assignee: Qingdao Haier Air Conditioner Gen Corp Ltd; Qingdao Haier Air Conditioning Electric Co Ltd; Haier Smart Home Co Ltd
Current assignee: Qingdao Haier Air Conditioner Gen Corp Ltd; Qingdao Haier Air Conditioning Electric Co Ltd; Haier Smart Home Co Ltd
Priority date: 2022-07-25
Filing date: 2022-07-25
Publication date: 2023-02-03
Anticipated expiration: 2032-07-25

Abstract

The utility model discloses a many online heat transfer units, include: a heat exchanger having a refrigerant inlet and outlet and a water inlet and outlet; the refrigerant inlet pipeline is communicated with the refrigerant inlet, and a refrigerant cut-off valve is connected in series on the refrigerant inlet pipeline; one end of the refrigerant outlet pipeline is communicated with the refrigerant outlet, and the other end of the refrigerant outlet pipeline is communicated with an inlet of the compressor; and the first end of the bypass pipeline is communicated with the refrigerant inlet pipeline and is communicated with the upstream of the refrigerant stop valve, the second end of the bypass pipeline is communicated with the refrigerant outlet pipeline, and a bypass valve is connected in series on the bypass pipeline. The utility model discloses increased bypass pipeline and bypass valve, the refrigerant temperature in refrigerant inlet pipeline is low excessively, and the bypass valve is opened to the accessible, closes the mode of refrigerant trip valve, avoids freezing the problem that leads to heat exchanger frost crack at heat exchanger inner loop's water. The utility model also discloses a many online.

Description

Multi-split heat exchange unit and multi-split air conditioner

Technical Field

The utility model relates to an air conditioner technical field especially relates to a many online heat transfer units and many online.

Background

The multi-split air conditioning system is an air conditioning system with an outdoor unit and a plurality of indoor units, adapts to load changes of each room by changing the flow of refrigerant, and mainly comprises the outdoor unit, refrigerant pipelines, the indoor units and related control devices. Due to the characteristics of flexible use, convenient installation and the like of the multi-split air conditioning system, the multi-split air conditioning system is more and more widely applied in life.

As shown in fig. 1, a commonly used heat exchange unit in a multi-split air conditioning system is a heat exchange unit for exchanging heat between water and a refrigerant, when cooling and defrosting are performed, the temperature of the refrigerant flowing through a heat exchanger 1 of the multi-split air conditioning unit through a refrigerant inlet pipeline 2 is relatively low, at this time, water expands under a low-temperature refrigerant, and the heat exchanger 1 is frozen and cracked, so that the multi-split air conditioning system cannot be normally used.

Therefore, how to prevent the heat exchanger from generating a frost crack risk when the temperature of the refrigerant is low and ensure the normal and stable operation of the multi-split heat exchange unit is a technical problem to be solved by technical personnel in the field at present.

SUMMERY OF THE UTILITY MODEL

In view of this, an object of the present invention is to provide a multi-split heat exchange unit, so as to prevent the occurrence of frost cracking risk when the temperature of the refrigerant is low, and ensure the normal and stable operation of the multi-split heat exchange unit;

another objective of the present invention is to provide a multi-split air conditioner with the above multi-split air conditioner heat exchange unit.

In order to achieve the above object, the present invention provides the following technical solutions:

a multi-split heat exchange unit is characterized by comprising:

a heat exchanger having a refrigerant inlet and outlet and a water inlet and outlet;

the refrigerant inlet pipeline is communicated with the refrigerant inlet and is connected with a refrigerant cut-off valve in series;

one end of the refrigerant outlet pipeline is communicated with the refrigerant outlet, and the other end of the refrigerant outlet pipeline is communicated with an inlet of the compressor;

and the first end of the bypass pipeline is communicated with the refrigerant inlet pipeline and is communicated with the upstream of the refrigerant stop valve, the second end of the bypass pipeline is communicated with the refrigerant outlet pipeline, and a bypass valve is connected in series on the bypass pipeline.

Optionally, in the multi-split air-conditioning heat exchange unit, the bypass valve is a manual switch valve or an automatic switch valve.

Optionally, in the above multiple on-line heat exchange unit, a check valve is connected in series on the bypass line, and the check valve is located between the bypass valve and the second end of the bypass line, and in a direction from the bypass valve to the second end of the bypass line, the check valve is in a conducting state.

Optionally, in the multi-split air conditioning unit, the refrigerant cut-off valve is an electronic expansion valve.

Optionally, in the above multiple on-line heat exchange unit, the refrigerant cut-off valve is an electromagnetic on-off valve disposed on the refrigerant inlet pipeline downstream of the electronic expansion valve, and the first end of the bypass pipeline is communicated between the electronic expansion valve and the electromagnetic on-off valve.

Optionally, in the multi-split air-conditioning heat exchange unit, the bypass pipeline is connected in series with 1 or more throttling pressure reducing devices.

Optionally, in the multiple on-line heat exchange unit, the throttling and pressure reducing device is disposed between the bypass valve and the first end of the bypass pipeline; or,

the throttling and pressure reducing device is arranged between the bypass valve and the second end of the bypass pipeline; or,

the throttling and pressure reducing devices are arranged between the bypass valve and the first end and the second end of the bypass pipeline.

Optionally, in the multi-split heat exchange unit, the throttling pressure reducing device is a capillary tube or an electronic expansion valve.

Optionally, in the above multi-split air conditioning unit, two filters are disposed on the refrigerant inlet pipeline, and a first end of the bypass pipeline is communicated between the two filters.

Optionally, in the multi-split air conditioning heat exchange unit, the bypass valve is an electromagnetic valve, the refrigerant cut-off valve is an electronic expansion valve, a first temperature sensor is arranged on the refrigerant inlet pipeline, a second temperature sensor is arranged on the refrigerant outlet pipeline, a third temperature sensor is arranged on the water inlet pipeline, and a fourth temperature sensor is arranged on the water outlet pipeline;

when a first condition is met, the refrigerant cut-off valve is closed, and the bypass valve is opened, and when a second condition is met, the refrigerant cut-off valve is opened, and the bypass valve is closed;

the first condition includes: the temperature detected by the first temperature sensor is lower than a first preset temperature or the temperature detected by the second temperature sensor is lower than a second preset temperature, the temperature detected by the fourth temperature sensor is lower than a third preset temperature, and the temperature is continuously reduced within a preset time, wherein the second preset temperature is lower than the first preset temperature, the second preset temperature and the first preset temperature are both lower than 0 ℃, and the third preset temperature is higher than 0 ℃;

the second condition includes: the temperature that one of the first temperature sensor with in the second temperature sensor detected is greater than the fourth and predetermines the temperature, and the temperature that one of the third temperature sensor with in the fourth temperature sensor detected is greater than the fifth and predetermines the temperature, wherein, the fifth is predetermine the temperature and is greater than the fourth and predetermine the temperature, just the fifth is predetermine the temperature and is greater than the third and predetermine the temperature, the fourth is predetermine the temperature and is greater than 0 ℃.

Optionally, in the multi-split air-conditioning heat exchange unit, the first preset temperature is-1 ℃ to-3 ℃; the second preset temperature is-3 ℃ to-7 ℃; the third preset temperature is 3-7 ℃; the fourth preset temperature is 3-7 ℃; the fifth preset temperature is 8-12 ℃; the preset time is 2-4 min.

The utility model provides a many online heat transfer units, bypass pipeline and bypass valve have been increased on the basis of current many online heat transfer units, refrigerant temperature in refrigerant inlet pipeline crosses lowly, make there is the risk of freezing in the water of heat exchanger inner loop, when causing heat exchanger to appear the frost crack risk, the bypass valve is opened to the accessible, the mode of closing the refrigerant trip valve, make refrigerant in the refrigerant inlet pipeline directly return refrigerant outlet pipeline through the bypass pipeline, and no longer pass through heat exchanger, just also avoided, the problem that the water of heat exchanger inner loop freezes and leads to heat exchanger frost crack leads to.

When the temperature of the refrigerant in the refrigerant inlet pipeline cannot cause the water circulating in the heat exchanger to be frozen, the bypass pipeline can be shielded by closing the bypass valve and opening the refrigerant stop valve, so that the refrigerant in the refrigerant inlet pipeline enters the heat exchanger to exchange heat, and the related functions of the air conditioning system are completed.

A multi-split air conditioner comprises a multi-split air conditioner heat exchange unit, wherein the multi-split air conditioner heat exchange unit is any one of the multi-split air conditioner heat exchange units.

The utility model discloses a many online, owing to have above-mentioned many online heat transfer units, consequently have all technological effects of above-mentioned many online heat transfer units concurrently, this text is no longer repeated here.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a multi-split heat exchange unit in the prior art;

fig. 2 is a schematic structural diagram of a multi-split heat exchange unit provided in the first embodiment of the present invention;

fig. 3 is a schematic structural diagram of a multi-split heat exchange unit provided in the second embodiment of the present invention;

fig. 4 is a schematic structural diagram of a multi-split heat exchange unit provided in a third embodiment of the present invention;

fig. 5 is a schematic structural view of a multi-split heat exchange unit provided by the fourth embodiment of the present invention.

The meaning of the various reference numerals in figures 1 to 5 is as follows:

the heat exchanger is 1, the refrigerant inlet pipeline is 2, the heat exchanger is 100, the refrigerant inlet is 101, the refrigerant outlet is 102, the water inlet is 103, the water outlet is 104, the first temperature sensor is 105, the second temperature sensor is 106, the third temperature sensor is 107, the fourth temperature sensor is 108, the electronic expansion valve is 200, the refrigerant inlet pipeline is 201, the refrigerant outlet pipeline is 202, the electromagnetic on-off valve is 203, the filter is 204, the bypass pipeline is 300, the bypass valve is 301, the check valve is 302, and the throttling and pressure reducing device is 303.

Detailed Description

The core of the utility model is to provide a multi-split heat exchange unit to prevent the heat exchanger from the risk of frost cracking when the temperature of the refrigerant is low, and ensure the normal and stable operation of the multi-split heat exchange unit;

the other core of the present invention is to provide a multi-split air conditioner with the above multi-split air conditioner heat exchange unit.

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

As shown in fig. 2-5, an embodiment of the present invention discloses a multi-split heat exchange unit, which includes a heat exchanger 100, a refrigerant inlet pipeline 201, a refrigerant outlet pipeline 202 and a bypass pipeline 300.

The heat exchanger 100 includes a refrigerant inlet 101, a refrigerant outlet 102, a water inlet 103, and a water outlet 104. The heat exchanger 100 is a water-fluorine heat exchanger commonly used in the prior art, and the detailed structure thereof is not described herein.

The refrigerant inlet pipeline 201 is communicated with the refrigerant inlet 101, a refrigerant cut-off valve is connected in series on the refrigerant inlet pipeline 201 and used for cutting off and opening the refrigerant inlet pipeline 201, when the refrigerant cut-off valve is closed, a path of the refrigerant entering the heat exchanger 100 through the refrigerant inlet pipeline 201 is cut off, and when the refrigerant cut-off valve is opened, a path of the refrigerant entering the heat exchanger 100 through the refrigerant inlet pipeline 201 is communicated, so that whether the refrigerant enters the heat exchanger 100 or not can be controlled through opening and closing of the refrigerant cut-off valve. One end of the refrigerant outlet line 202 is connected to the refrigerant outlet 102, and the other end is connected to the inlet of the compressor.

The bypass line 300 has a first end connected to the refrigerant inlet line 201 and connected to an upstream side of the refrigerant cutoff valve, a second end connected to the refrigerant outlet line 202, a bypass valve 301 connected in series to the bypass line 300, the bypass valve 301 being configured to cut and open the bypass line 300, when the bypass valve 301 is closed, a path of the refrigerant passing through the bypass line 300 is cut, the refrigerant passes through the heat exchanger 100, and when the bypass valve 301 is opened, a path of the refrigerant passing through the bypass line 300 is connected, so that whether the refrigerant passes through the bypass line 300 is controlled by opening and closing the bypass valve 301. Specifically, the bypass valve 301 may be a manual opening and closing valve or an automatic opening and closing valve. When the bypass valve 301 is a manual on-off valve, an operator is required to manually open or close the bypass valve 301 according to requirements; when the bypass valve 301 is an automatic on-off valve, it may be matched with a sensor, and when the condition is satisfied, the bypass valve 301 is automatically controlled to be opened or closed.

The utility model provides a many online heat transfer units, bypass pipeline 300 and bypass valve 301 have been increased on current many online heat transfer units's basis, refrigerant temperature in refrigerant inlet pipeline 201 is low excessively, make there is the risk of freezing in heat exchanger 100 inner loop's water, when causing heat exchanger 100 to appear the frost crack risk, bypass valve 301 is opened to the accessible, the mode of refrigerant trip valve is closed, make refrigerant in refrigerant inlet pipeline 201 directly return refrigerant outlet pipeline 202 through bypass pipeline 300, and no longer through heat exchanger 100, just also avoided, the problem that freezes at heat exchanger 100 inner loop's water and leads to heat exchanger 100 frost crack.

When the temperature of the refrigerant in the refrigerant inlet line 201 does not cause the water circulating in the heat exchanger 100 to freeze, the bypass line 300 may be shielded by closing the bypass valve 301 and opening the refrigerant cut-off valve, so that the refrigerant in the refrigerant inlet line 201 enters the heat exchanger 100 to exchange heat, thereby completing the related functions of the air conditioning system.

In order to prevent the refrigerant flowing through the bypass line 300 from flowing backward when the bypass valve 301 on the bypass line 300 is in the open state, in this embodiment, a check valve 302 is connected in series with the bypass line 300, and the check valve 302 is located between the bypass valve 301 and the second end of the bypass line 300, that is, the bypass valve 301 is located downstream of the bypass line 300, and in the direction from the bypass valve 301 to the second end of the bypass line 300, the check valve 302 is in the on state, that is, the refrigerant can only flow from the refrigerant inlet line 201 to the refrigerant outlet line 202 through the bypass line 300, and cannot flow from the refrigerant outlet line 202 to the refrigerant inlet line 201 through the bypass line 300.

As shown in fig. 2-4, in an embodiment of the present invention, the refrigerant cut-off valve may be an electronic expansion valve 200, that is, the electronic expansion valve 200 disposed on a refrigerant inlet pipeline 201 of the air conditioning system may be used as the refrigerant cut-off valve in this embodiment, that is, in this embodiment, the cut-off function of the electronic expansion valve 200 is utilized.

When the temperature of the refrigerant in the refrigerant inlet pipeline 201 is low, the electronic expansion valve 200 is closed, the bypass valve 301 is opened, the path of the refrigerant entering the heat exchanger 100 through the refrigerant inlet pipeline 201 is cut off, the refrigerant in the refrigerant inlet pipeline 201 flows to the refrigerant outlet pipeline 202 through the bypass pipeline 300 and enters the compressor, and the refrigerant does not pass through the heat exchanger 100 any more, so that the problem that the heat exchanger is frozen and cracked due to the freezing of water circulating in the heat exchanger is avoided. In this embodiment, the electronic expansion valve 200 originally existing on the refrigerant inlet pipeline 201 is used as the refrigerant cutoff valve, and the cutoff operation of the bypass pipeline 300 can be completed by using the cutoff function of the electronic expansion valve 200 without adding a related cutoff valve on the refrigerant inlet pipeline 201, thereby reducing the system cost.

As shown in fig. 5, in an embodiment of the present invention, the refrigerant cut-off valve is an electromagnetic on-off valve 203 disposed on the refrigerant inlet pipeline 201, that is, an electromagnetic on-off valve 203 is additionally disposed on the refrigerant inlet pipeline 201 of the air conditioning system for cutting off the refrigerant inlet pipeline 201.

When the electromagnetic on-off valve 203 is closed and the bypass valve 301 is opened, the refrigerant in the refrigerant inlet line 201 flows to the refrigerant outlet line 202 through the bypass line 300, enters the compressor, and no longer passes through the heat exchanger 100, the refrigerant enters the compressor while maintaining a liquid state in the refrigerant inlet line 201, and liquid compression is easily generated. To avoid this problem, in the present embodiment, the electromagnetic on-off valve 203 may be disposed downstream of the electronic expansion valve 200 on the refrigerant inlet line 201, and the first end of the bypass line 300 may be communicated between the electronic expansion valve 200 and the electromagnetic on-off valve 203, such that the electronic expansion valve 200 is located upstream of the bypass line 300.

The electronic expansion valve 200 on the refrigerant inlet pipeline 201 can also provide a throttling and pressure reducing effect for the circulating refrigerant of the bypass pipeline 300, when the electromagnetic on-off valve 203 is closed and the bypass valve 301 is opened, the refrigerant in the refrigerant inlet pipeline 201 flows to the refrigerant outlet pipeline 202 through the bypass pipeline 300 after being subjected to throttling, pressure reducing and gasifying by the electronic expansion valve 200, and enters the compressor, so that the risk of liquid compression of the compressor is prevented.

As shown in fig. 2-4, in an embodiment of the present invention, a throttling pressure reducing device 303 may be additionally added to the bypass line 300, that is, the throttling pressure reducing device 303 is connected in series to the bypass line 300, specifically, the number of the throttling pressure reducing devices 303 is 1 or more, the throttling pressure reducing device 303 is a device capable of realizing throttling pressure reduction or gasification, such as a capillary tube or an electronic expansion valve, and the capillary tube is taken as an example for description.

For example, a throttling pressure reducing device 303 may be disposed between the bypass valve 301 and the first end of the bypass line 300 as shown in FIG. 2; may also be provided between the check valve 302 and the second end of the bypass line 300 as shown in fig. 3; of course, it may be disposed between the bypass valve 301 and the first end of the bypass line 300 and the check valve 302 and the second end of the bypass line 300 as shown in fig. 4.

As shown in fig. 2-4, the refrigerant inlet line 201 is further provided with two filters 204, the filters 204 are used for removing impurities in the refrigerant, and the first end of the bypass line 300 is communicated between the two filters 204, so that the refrigerant passing through the bypass line 300 is filtered by the filters 204, and the impurities are removed.

In an embodiment of the present invention, the bypass valve 301 is an electromagnetic valve, and the refrigerant cut-off valve is the electronic expansion valve 200. As shown in fig. 2, a first temperature sensor 105 is provided on the refrigerant inlet line 201, a second temperature sensor 106 is provided on the refrigerant outlet line 202, a third temperature sensor 107 is provided on the water inlet line, and a fourth temperature sensor 108 is provided on the water outlet line.

When the first condition is met, the refrigerant cut-off valve is closed, the bypass valve 301 is opened, and at the moment, all refrigerants flow through the bypass pipeline 300 to enter the compressor, so that the heat exchanger 100 is prevented from being frozen due to expansion of water under low-temperature refrigerants; when the second condition is met, the refrigerant cut-off valve is opened, the bypass valve 301 is closed, and at the moment, all refrigerants flow through the heat exchanger and enter the compressor, so that the basic circulation function of the air conditioning system is completed.

Specifically, the first condition includes: the temperature detected by the first temperature sensor 105 is lower than a first preset temperature or the temperature detected by the second temperature sensor 106 is lower than a second preset temperature, and the temperature detected by the fourth temperature sensor 108 is lower than a third preset temperature, and the temperature continuously decreases within a preset time, wherein the second preset temperature is lower than the first preset temperature, the second preset temperature and the first preset temperature are both less than 0 ℃, and the third preset temperature is greater than 0 ℃. The temperature detected by at least one of the first temperature sensor 105 and the second temperature sensor 106 is lower than 0 ℃, which indicates that the refrigerant temperature is low enough that there may be a problem with freezing of water. If the temperature detected by the fourth temperature sensor 108 is lower than the third preset temperature and continuously decreases within the preset time, that is, the temperature of the water is lower than the third preset temperature and continuously decreases, which indicates that the temperature of the water has a tendency of gradually decreasing, the bypass pipeline 300 may be opened to directly return the refrigerant to the compressor.

The second condition includes: one of the first temperature sensor 105 and the second temperature sensor 106 detects a temperature greater than a fourth preset temperature, and one of the third temperature sensor 107 and the fourth temperature sensor 108 detects a temperature greater than a fifth preset temperature, wherein the fifth preset temperature is greater than the fourth preset temperature, the fifth preset temperature is greater than the third preset temperature, and the fourth preset temperature is greater than 0 ℃. The temperature detected by one of the first temperature sensor 105 and the second temperature sensor 106 is greater than 0 ℃, which indicates that the temperature of the refrigerant is high and is not enough to freeze water, and the circulation function of the air conditioning system can be maintained.

Specifically, the first preset temperature is-1 ℃ to-3 ℃, for example, -2 ℃; the second preset temperature is-3 ℃ to-7 ℃, for example-5 ℃; the third preset temperature is 3-7 ℃, for example-5 ℃; the fourth preset temperature is 3-7 ℃, for example, 5 ℃; the fifth preset temperature is 8-12 ℃, for example, 10 ℃; the preset time is 2-4 min, for example, 3min, and the temperature continuously decreases within the preset time, and the judgment can be performed by acquiring the temperature once by the fourth temperature sensor 108 at intervals (for example, 10 s), for example, if the temperature acquired in the last 10s minus the temperature acquired in the first 10s is less than 0 ℃, and the temperature acquired in the last 10s minus the temperature acquired in the first 10s within the continuous preset time is less than 0 ℃, the temperature continuously decreases within the preset time.

It should be noted that all preset temperatures are not limited to the temperatures described in the embodiments of the present invention, and may be other values as long as the requirement for freeze protection is satisfied.

The embodiment of the utility model provides a still disclose a multi-online, include as above the embodiment the multi-online heat transfer unit that discloses, consequently have above-mentioned all technological effects of multi-online heat transfer unit concurrently, this text is no longer repeated here.

It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.

As used in this application and the appended claims, the terms "a," "an," "the," and/or "the" are not intended to be inclusive in the singular, but rather are intended to be inclusive in the plural unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that steps and elements are included which are explicitly identified, that the steps and elements do not form an exclusive list, and that a method or apparatus may include other steps or elements. An element defined by the phrase "comprising a … …" does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.

In the following, the terms "first", "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

The principles and embodiments of the present invention have been explained herein using specific examples, and the above descriptions of the embodiments are only used to help understand the core concepts of the present invention. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, the present invention can be further modified and modified, and such modifications and modifications also fall within the scope of the appended claims.

Claims

1. A multi-split heat exchange unit is characterized by comprising:

a heat exchanger (100) having a refrigerant inlet (101), a refrigerant outlet (102), a water inlet (103), and a water outlet (104);

the refrigerant inlet pipeline (201) is communicated with the refrigerant inlet (101), and a refrigerant cut-off valve is connected to the refrigerant inlet pipeline (201) in series;

one end of the refrigerant outlet pipeline (202) is communicated with the refrigerant outlet (102), and the other end of the refrigerant outlet pipeline is communicated with an inlet of the compressor;

and a bypass pipeline (300), wherein the first end of the bypass pipeline (300) is communicated with the refrigerant inlet pipeline (201) and is communicated with the upstream of the refrigerant cut-off valve, the second end of the bypass pipeline is communicated with the refrigerant outlet pipeline (202), and a bypass valve (301) is connected to the bypass pipeline (300) in series.

2. The multi-online heat exchange unit as recited in claim 1, wherein the bypass valve (301) is a manual on-off valve or an automatic on-off valve.

3. A multi-split heat exchange unit as claimed in claim 1, wherein a check valve (302) is connected in series on the bypass line (300), and the check valve (302) is located between the bypass valve (301) and the second end of the bypass line (300), and the check valve (302) is in a conducting state in the direction from the bypass valve (301) to the second end of the bypass line (300).

4. A multi-split heat exchange unit as claimed in claim 1, wherein the refrigerant cut-off valve is an electronic expansion valve (200).

5. A multi-split heat exchange unit as claimed in any one of claims 1 to 3, wherein the refrigerant cut-off valve is an electromagnetic on-off valve (203) disposed on the refrigerant inlet pipeline (201) downstream of the electronic expansion valve (200), and the first end of the bypass pipeline (300) is communicated between the electronic expansion valve (200) and the electromagnetic on-off valve (203).

6. The multi-split heat exchange unit as recited in any one of claims 1-4, wherein a throttling pressure reducing device (303) is connected in series on the bypass pipeline (300), and the number of the throttling pressure reducing devices (303) is 1 or more.

7. The multi-online heat exchange unit according to claim 6, wherein the throttling and pressure reducing device (303) is disposed between the bypass valve (301) and the first end of the bypass line (300); or,

the throttling and pressure reducing device (303) is arranged between the bypass valve (301) and the second end of the bypass pipeline (300); or,

and the throttling and pressure reducing devices (303) are arranged between the bypass valve (301) and the first end and the second end of the bypass pipeline (300).

8. The multi-split heat exchange unit as recited in claim 7, wherein the throttling and depressurizing device (303) is a capillary tube or an electronic expansion valve.

9. A multi-split heat exchange unit as claimed in any one of claims 1 to 4, wherein two filters (204) are arranged on the refrigerant inlet pipeline (201), and the first end of the bypass pipeline (300) is communicated between the two filters (204).

10. A multi-split heat exchange unit as claimed in claim 1, wherein the bypass valve (301) is a solenoid valve, the refrigerant cut-off valve is an electronic expansion valve (200), a first temperature sensor (105) is disposed on the refrigerant inlet pipeline (201), a second temperature sensor (106) is disposed on the refrigerant outlet pipeline (202), a third temperature sensor (107) is disposed on the water inlet pipeline, and a fourth temperature sensor (108) is disposed on the water outlet pipeline;

when a first condition is met, the refrigerant cut-off valve is closed, and the bypass valve (301) is opened, and when a second condition is met, the refrigerant cut-off valve is opened, and the bypass valve (301) is closed;

the first condition includes: the temperature detected by the first temperature sensor (105) is lower than a first preset temperature or the temperature detected by the second temperature sensor (106) is lower than a second preset temperature, the temperature detected by the fourth temperature sensor (108) is lower than a third preset temperature, and the temperature is continuously reduced within a preset time, wherein the second preset temperature is lower than the first preset temperature, the second preset temperature and the first preset temperature are both lower than 0 ℃, and the third preset temperature is higher than 0 ℃;

the second condition includes: one of the first temperature sensor (105) and the second temperature sensor (106) detects a temperature greater than a fourth preset temperature, and one of the third temperature sensor (107) and the fourth temperature sensor (108) detects a temperature greater than a fifth preset temperature, wherein the fifth preset temperature is greater than the fourth preset temperature, the fifth preset temperature is greater than the third preset temperature, and the fourth preset temperature is greater than 0 ℃.

11. The multi-online heat exchange unit according to claim 10, wherein the first preset temperature is-1 ℃ to-3 ℃; the second preset temperature is-3 ℃ to-7 ℃; the third preset temperature is 3-7 ℃; the fourth preset temperature is 3-7 ℃; the fifth preset temperature is 8-12 ℃; the preset time is 2-4 min.

12. A multi-split air conditioner comprising multi-split air conditioner heat exchange units, wherein the multi-split air conditioner heat exchange units are as defined in any one of claims 1 to 11.