CN115751466A

CN115751466A - Air conditioning system

Info

Publication number: CN115751466A
Application number: CN202211430167.2A
Authority: CN
Inventors: 何明顺; 陈林; 黄曙良
Original assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Current assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Priority date: 2022-11-15
Filing date: 2022-11-15
Publication date: 2023-03-07

Abstract

The invention discloses an air conditioning system, which is characterized in that the state of a condenser or an evaporator is switched for an outdoor heat exchanger through a first reversing valve, the state of the condenser or the evaporator is switched for an indoor heat exchanger through a second reversing valve, when defrosting is needed during the heating period of the air conditioning system, the second reversing valve is kept unchanged to keep the heating mode of the indoor heat exchanger unchanged, the first reversing valve is controlled to reverse, the outdoor heat exchanger is switched from the evaporator to the condenser to defrost, the refrigerant condensed from the outdoor heat exchanger and the indoor heat exchanger is mixed in a subcooler, the relatively high-temperature refrigerant promotes the relatively low-temperature refrigerant to be gasified, and the relatively high-temperature refrigerant returns to the air suction side of a compressor after passing through a gas-liquid separator, so that the problem that the temperature of the indoor environment is reduced due to the fact that the air conditioning system is switched into a refrigeration refrigerant loop in the prior art is solved, the defrosting effect is good, and the comfortable experience of users is not influenced.

Description

Air conditioning system

Technical Field

The invention relates to the technical field of air conditioners, in particular to an air conditioning system capable of defrosting an outdoor heat exchanger under the condition of not changing the operation of a heating mode.

Background

When the air conditioner operates in the heating mode, if the outdoor temperature is too low, the outdoor heat exchanger will frost, and the defrosting operation needs to be carried out on the outdoor heat exchanger at a proper time.

In the conventional defrosting of the outdoor heat exchanger of the air conditioner, a mode of switching a reversing valve into a refrigerating refrigerant loop is mostly adopted, the indoor heat exchanger is converted into an evaporator, the outdoor heat exchanger is converted into a condenser, and a frost layer on the surface of the outdoor heat exchanger is melted by heat dissipated by the condenser through condensation.

However, this defrosting mode may cause the indoor heat exchanger to absorb heat from the indoor space by converting into an evaporator, which may result in a drop of the indoor ambient temperature and an uncomfortable experience for the user.

Disclosure of Invention

The invention aims to provide an air conditioning system, which is characterized in that the state of a condenser or an evaporator is switched for an outdoor heat exchanger through a first reversing valve, the state of the condenser or the evaporator is switched for an indoor heat exchanger through a second reversing valve, when defrosting is needed during heating of the air conditioning system, the second reversing valve is kept unchanged to keep the heating mode of the indoor heat exchanger unchanged, the first reversing valve is controlled to reverse, the outdoor heat exchanger is switched from the evaporator to the condenser to defrost, the problem that the temperature of the indoor environment is reduced due to the fact that the air conditioning system is switched to a refrigeration refrigerant loop in the prior art is solved, the defrosting effect is good, and the comfort experience of users is not influenced.

In order to realize the purpose of the invention, the invention is realized by adopting the following technical scheme:

an air conditioning system is proposed, comprising:

an outdoor unit and an indoor unit; the outdoor unit comprises an outdoor heat exchanger (3), and the indoor unit comprises an indoor heat exchanger (4);

the first reversing valve (1) is arranged in the outdoor unit and used for switching the state of a condenser or an evaporator of the outdoor heat exchanger (3);

a second direction switching valve (2) disposed in the outdoor unit for switching the state of the condenser or the evaporator of the indoor heat exchanger (4);

a controller configured to:

when the air conditioning system operates in a heating mode, controlling a first reversing valve (1) and a second reversing valve (2) to enable an outdoor heat exchanger (3) to be used as an evaporator and an indoor heat exchanger (4) to be used as a condenser;

when the air conditioning system operates in a heating mode and needs defrosting, maintaining the second reversing valve (2) and controlling the first reversing valve (1) to reverse, so that the indoor heat exchanger (4) is maintained as a condenser to perform heating, and the outdoor heat exchanger (3) is switched to be used as the condenser to perform defrosting; the refrigerant after being released heat by the indoor heat exchanger (4) and the refrigerant after being released heat by the outdoor heat exchanger (3) are mixed to exchange heat and gasify and then return to the suction side of the compressor.

Compared with the prior art, the air conditioning system has the advantages and positive effects that: in the air conditioning system provided by the invention, the state switching of a condenser or an evaporator is carried out on an outdoor heat exchanger (3) by adopting a first reversing valve (1), and the state switching of the condenser or the evaporator is carried out on an indoor heat exchanger (4) by adopting a second reversing valve (2); when the air conditioning system is used for heating normally, the first reversing valve (1) and the second reversing valve (2) are controlled, so that the indoor heat exchanger (4) is used as a condenser, and the outdoor heat exchanger (3) is used as an evaporator to heat indoors; when the outdoor heat exchanger (3) frosts in the heating process to meet the defrosting condition, the state of the second reversing valve (2) is kept unchanged, the heating mode of the indoor heat exchanger (4) is kept unchanged, namely the indoor heat exchanger (4) is kept to be used as a condenser, the first reversing valve (1) is switched for reversing, so that the outdoor heat exchanger (3) is switched to be used as the condenser by an evaporator, the outdoor heat exchanger (3) is defrosted by the released heat, and the refrigerants released by the indoor heat exchanger (4) and the outdoor heat exchanger (3) are mixed in a pipeline and return to the air suction side of the compressor after heat exchange and gasification; in the whole defrosting process, the indoor heat exchanger (4) is still in a heating state of the condenser, the problem that the indoor environment temperature is reduced due to the fact that the indoor heat exchanger is switched to the evaporator in the traditional mode is solved, the defrosting effect is good, and the user comfort experience is not influenced.

In some embodiments of the invention, the outdoor unit consists of a compressor (5), a first reversing valve (1), an outdoor heat exchanger (3), a subcooler (7) and a gas-liquid separator (6) which are connected in series; the D end of the second reversing valve (2) and the D end of the first reversing valve (1) are both connected with the exhaust end of the compressor (5), the C end of the second reversing valve is connected with the indoor heat exchanger (4), and the S end of the second reversing valve and the S end of the first reversing valve (1) are both connected with the inlet of the gas-liquid separator (6); the E end of the first reversing valve (1) is connected with the outdoor heat exchanger (3); a controller configured to: when the air conditioning system runs in a heating mode, controlling a first reversing valve (1) and a second reversing valve (2) to enable the exhaust side of a compressor (5) to be communicated with an indoor heat exchanger (4) and enable an outdoor heat exchanger (3) to be communicated with the suction side of the compressor (5); when the air conditioning system is operated in a heating mode and defrosting is needed, the second reversing valve (2) is maintained and the first reversing valve (1) is switched, so that the exhaust side of the compressor (1) is communicated with the outdoor heat exchanger (3).

Compared with the prior art, the air conditioning system has the advantages and positive effects that: in the air conditioning system provided by the invention, the state switching of a condenser or an evaporator is carried out on an outdoor heat exchanger (3) by adopting a first mode (1), and the state switching of the condenser or the evaporator is carried out on an indoor heat exchanger (4) by adopting a second mode (2); when the air conditioning system normally heats, the first (1) and the second (2) are controlled, so that the exhaust side of the compressor (5) is communicated with the indoor heat exchanger (4), the indoor heat exchanger (4) is used as an evaporator, the outdoor heat exchanger (3) is communicated with the suction side of the compressor (5), and the indoor heat exchanger (4) is used as a condenser; when the outdoor heat exchanger (3) is frosted to meet the defrosting condition in the heating process, the state of the second reversing valve (2) is kept unchanged, the heating mode of the indoor heat exchanger (4) is kept unchanged, namely the indoor heat exchanger (4) is kept to be used as an evaporator, the first reversing valve (1) is switched to reverse, the exhaust side of the compressor (5) is communicated with the outdoor heat exchanger (3), the outdoor heat exchanger (3) is switched to be used as a condenser from the evaporator, one part of high-temperature and high-pressure refrigerant discharged from the compressor (5) enters the indoor heat exchanger (4) to maintain the indoor temperature, the other part of the high-temperature and high-pressure refrigerant enters the outdoor heat exchanger (3) to be condensed and released, the released heat is implemented, the outdoor heat-released refrigerant returns to the gas-liquid separator (6) after passing through the subcooler (7) and returns to the gas-liquid separator (6) through the gas-liquid separator (7), and returns to the gas-suction side of the compressor (5); in the whole defrosting process, the indoor heat exchanger (4) is still in a heating state of the condenser, the problem that the indoor environment temperature is reduced due to the fact that the indoor heat exchanger is switched to the evaporator in the traditional mode is solved, the defrosting effect is good, and the user comfort experience is not influenced.

In the invention, the subcooler (7) is the existing component of the air conditioning system, and in the refrigeration mode, the subcooler (7) subcools the refrigerant condensed from the outdoor heat exchanger (3), thereby ensuring that the temperature of the liquid refrigerant entering the indoor heat exchanger (4) is reduced, reducing flash gas generated during or after throttling and further improving the refrigeration capacity of the system; in combination with the system architecture provided by the invention, a new application function is provided, during heating and defrosting operation, the refrigerants condensed from the outdoor heat exchanger (3) and the indoor heat exchanger (4) are mixed in the subcooler (7), the high-temperature refrigerants and the low-temperature refrigerants exchange heat to promote gasification and then return to the gas-liquid separator (6), and after gas-liquid separation of the gas-liquid separator (6), the gaseous refrigerants return to the compressor (5).

In some embodiments of the present invention, the indoor unit further includes: an indoor fan (9); an indoor electronic expansion valve (101) connected to the indoor side between the indoor heat exchanger (4) and the outdoor heat exchanger (3); the controller is configured to: when the air conditioning system operates in a heating mode and needs defrosting, adjusting the air volume of the indoor fan (9) and the opening degree of the indoor electronic expansion valve (101) to ensure that the superheat degree of a refrigerant condensed by the indoor heat exchanger (4) does not exceed a first preset superheat degree; the first preset superheat degree meets the condition that the refrigerant condensed by the indoor heat exchanger (4) is in a gas state or a gas-liquid two-phase state.

When the air conditioning system is operated in a heating mode and needs defrosting, the air volume of the indoor fan (9) and the opening degree of the indoor electronic expansion valve (101) are controlled, so that the superheat degree of the refrigerant condensed from the indoor heat exchanger (4) does not exceed a first preset superheat degree, the refrigerant condensed from the indoor heat exchanger (4) has the superheat degree but is not completely condensed into liquid, a high-temperature gas state or a high-temperature gas-liquid two-phase state is maintained, the refrigerant is mixed with the refrigerant entering the subcooler (7) from the indoor heat exchanger (4) in the subcooler (7), the refrigerant is gasified at the high temperature of the refrigerant, and the refrigerant entering the gas-liquid separator (6) is all gaseous refrigerant.

In some embodiments of the present invention, the outdoor unit further includes: an outdoor electronic expansion valve (102) connected to the outdoor side between the indoor heat exchanger (4) and the outdoor heat exchanger (3); the controller is configured to: when the air conditioning system operates in a heating mode and needs defrosting, adjusting the opening degree of the outdoor electronic expansion valve (102) to adjust the amount of refrigerant entering the outdoor heat exchanger (3) from the exhaust side of the compressor (5), so that the superheat degree of the refrigerant condensed from the outdoor heat exchanger (3) and the refrigerant condensed from the indoor heat exchanger (4) after being mixed in the subcooler (7) does not exceed a second preset superheat degree; the second preset superheat degree meets the condition that the mixed refrigerant is in a gas state or a gas-liquid two-phase state.

When the air conditioning system operates in a heating mode and needs defrosting, the outdoor heat exchanger (3) is switched to a condenser for use, the frosting condition and the defrosting requirement are combined, the heat release amount of condensation on the outdoor side can be realized by adjusting the opening degree of an outdoor electronic expansion valve (102), and meanwhile, the superheat degree of the refrigerant condensed from the outdoor heat exchanger (3) and the refrigerant condensed from the indoor heat exchanger (4) after being mixed in a subcooler (7) does not exceed a second preset superheat degree, wherein the second preset superheat degree meets the condition that the mixed refrigerant is in a gas state or a gas-liquid two-phase state; that is, after the refrigerant condensed by the indoor heat exchanger (4) and the refrigerant condensed by the outdoor heat exchanger (3) are mixed in the subcooler (7), the former can promote the latter to be completely gasified, and the refrigerant entering the gas-liquid separator (6) is ensured to be gaseous refrigerant.

In some embodiments of the present invention, the outdoor unit further includes: an EVB expansion valve (103) installed on a supercooling branch between the outdoor heat exchanger (3) and the subcooler (7); the controller is configured to: when the air conditioning system is operated in a heating mode and defrosting is needed, the opening degrees of the EVB expansion valve (103) and the outdoor electronic expansion valve (102) are adjusted according to defrosting requirements so as to adjust the quantity of refrigerants entering the outdoor heat exchanger (3).

In the embodiment, the supercooling branch where the EVB expansion valve (103) is located is not used as a supercooling branch, but used as a refrigerant loop of the outdoor heat exchanger (3), when the air conditioning system operates in a heating mode and needs defrosting, the outdoor heat exchanger (3) is switched from an evaporator to a condenser for use, and in combination with a frosting condition, the amount of refrigerant entering the outdoor heat exchanger (3) can be adjusted through the opening degrees of the EVB expansion valve (103) and the outdoor electronic expansion valve (102), so that the defrosting effect is improved based on different amounts of refrigerant; when the frost formation amount is small, the opening degree of the EVB expansion valve (103) is adjusted to be small, and when the frost formation amount is large, the opening degree of the EVB expansion valve (93) is adjusted to be large.

In some embodiments of the present invention, the outdoor unit further includes: the compressor bypass branch is arranged between the exhaust side of the compressor (5) and the inlet of the gas-liquid separator (6) and is formed by connecting a bypass electromagnetic valve (111) and a bypass capillary tube (112) in series; the controller is configured to: when the air conditioning system is operated in a heating mode and defrosting is needed, whether the bypass solenoid valve (111) is closed to communicate with the bypass branch of the compressor is determined according to the overheat state of the suction air of the compressor (5).

Based on the air conditioning system framework provided by the invention, in the whole defrosting process, a large amount of liquid refrigerants are generated in the outdoor heat exchanger (3) and the gas-liquid separator (6), so that the exhaust pressure, the suction pressure, the exhaust temperature and the like in the air conditioning system are possibly lower than corresponding target values, whether the bypass electromagnetic valve (111) needs to be closed or not can be judged according to the suction overheat state of the compressor (5), the bypass electromagnetic valve (111) is closed to communicate with the bypass branch of the compressor, so that the high-temperature and high-pressure refrigerants discharged by the compressor (5) enter the gas-liquid separator (6) to promote the gasification of the liquid refrigerants, the refrigerant suction amount of the compressor (5) is increased, the influence on the reliability of the compressor (5) caused by the suction and liquid return of the compressor is avoided, and the stable and reliable operation of a unit is ensured.

In some embodiments of the present invention, the outdoor unit further includes three refrigerant pipelines: a high pressure gas pipeline (121), a low pressure gas pipeline (122) and a liquid return pipeline (123); wherein the high-pressure gas pipeline (121) and the low-pressure gas pipeline (122) are both connected to the exhaust side of the compressor (5), and the liquid return pipeline (123) is connected to the suction side of the compressor (5); the indoor unit further includes: a cold-heat converter (13) connected between the high-pressure air pipe (121) and the low-pressure air pipe (122) of the outdoor unit and the indoor heat exchanger (4); the device comprises an expansion valve for controlling the on-off of a high-pressure air pipeline (121) and a low-pressure air pipeline (122), and a bypass capillary tube between the high-pressure air pipeline (121) and the low-pressure air pipeline (122); the controller is configured to: when the air conditioning system is operated in a heating mode or defrosting mode, the expansion valve on the side of the high-pressure air pipeline (121) is controlled to be opened, the expansion valve on the side of the low-pressure air pipeline (122) is controlled to be closed, and an indoor air pipe is connected with the high-pressure air pipeline (121).

Based on the air conditioning system provided by the embodiment of the invention, the control of the expansion valves on the high-pressure air pipeline (121) and the low-pressure air pipeline (122) of the cold-hot converter (13) is combined, so that the refrigeration and heating of a plurality of indoor units can be simultaneously operated, the outdoor heat exchanger (3) can be flexibly switched among defrosting modes in a refrigeration mode, a heating mode and a heating mode, the application of a two-control air conditioning system and a three-control air conditioning system can be simultaneously considered, and the flexibility and the popularization of the air conditioning system are improved.

In some embodiments of the invention, the end C and the end S of the first reversing valve (1) are in short circuit through a first capillary tube (81); and/or the end E and the end S of the second reversing valve (2) are in short circuit through a second capillary tube (82).

Because no matter in the process of heating or in the process of heating and defrosting, the first reversing valve (1) does not need to be reversed, refrigerant liquid can be accumulated at the idle end of the first reversing valve (1), in order to ensure that the first reversing valve (1) can not be smoothly blocked by liquid refrigerants in the reversing process, a first capillary tube (81) is additionally arranged between the C end and the S end of the first reversing valve, the accumulated refrigerants are bypassed to a gas-liquid separator (6) by the first capillary tube (81), and the situation that the accumulated refrigerant liquid blocks the reversing of the first reversing valve (1) is avoided. Similarly, in some embodiments of the invention, since the second reversing valve (2) does not need to reverse in the refrigeration process, the second reversing valve (2) may accumulate refrigerant liquid at the idle end, in order to ensure that the second reversing valve (2) is not obstructed by liquid refrigerant smoothly in the reversing process, a second capillary tube (82) is added between the end E and the end S, and the second capillary tube (82) bypasses the accumulated refrigerant to the gas-liquid separator (6), thereby preventing the accumulated refrigerant liquid from obstructing the reversing of the second reversing valve (2).

Other features and advantages of the present invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.

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 embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on the drawings without inventive labor.

Fig. 1 is a schematic system architecture of an air conditioning system according to the present invention;

fig. 2 is a schematic view illustrating a flow direction of a refrigerant in a cooling mode of the air conditioning system according to the present invention;

fig. 3 is a schematic view of a refrigerant flow direction in the heating mode of the air conditioning system according to the present invention;

fig. 4 is a schematic view illustrating a flow direction of a refrigerant for defrosting in the heating mode of the air conditioning system according to the present invention;

fig. 5 is a schematic diagram of a system architecture of an air conditioning system according to a first embodiment of the present invention;

fig. 6 is a schematic diagram of a system architecture of an air conditioning system according to a second embodiment of the present invention;

fig. 7 is a schematic system architecture diagram of an air conditioning system according to a third embodiment of the present invention;

fig. 8 is a schematic diagram of a system architecture of an air conditioning system according to a fourth embodiment of the present invention;

fig. 9 is a schematic diagram of a system architecture of an air conditioning system according to a fifth embodiment of the present invention;

fig. 10 is a schematic diagram of an internal structure of a cooling-heating converter (13) in the air conditioning system according to the fifth embodiment of the present invention;

fig. 11 is a schematic system configuration diagram of an air conditioning system according to a sixth embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the present application, it is to be understood that the terms "central," "upper," "lower," "front," "back," "top," "bottom," "inner," "outer," and the like are used in the orientations and positional relationships indicated in the figures, which are based on the orientations and positional relationships shown in the figures, and are used for convenience in describing the present application and for simplicity in description, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore should not be considered limiting.

In the description of the present application, it is to be understood that the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or as implying that the number of indicated technical features is indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, the meaning of "a plurality" is two or more unless otherwise specified.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in this application will be understood to be a specific case for those of ordinary skill in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize the application of other processes and/or the use of other materials.

The invention aims to provide a technical scheme on the traditional air conditioning system architecture, which comprises the following steps: the defrosting of the outdoor heat exchanger is realized without changing the heating mode, the defrosting and cooling-free effect is achieved, and the heating comfort level of the air-conditioning system is improved.

In view of the above technical objectives, according to the air conditioning system provided by the present invention, the state of the condenser or the evaporator is switched for the outdoor heat exchanger through the first reversing valve, the state of the condenser or the evaporator is switched for the indoor heat exchanger through the second reversing valve, and the controller is configured to control the first reversing valve and the second reversing valve when the air conditioning system operates in the heating mode, so that the indoor heat exchanger is used as the condenser and the outdoor heat exchanger is used as the evaporator, and when defrosting is required in the heating mode, the second reversing valve is maintained to be unchanged, the first reversing valve is controlled to reverse, and the outdoor heat exchanger is switched from the evaporator to the condenser for use, so that the outdoor heat exchanger can defrost the surface of the outdoor heat exchanger through heat release of the refrigerant, and during the period, the refrigerant after heat release by the indoor heat exchanger and the refrigerant after heat release by the outdoor heat exchanger are mixed and return to the air suction side of the compressor after heat exchange and gasification.

In the whole defrosting process, the indoor heat exchanger (4) is still in a heating state of the condenser, the problem that the indoor environment temperature is reduced due to the fact that the indoor heat exchanger is switched into the evaporator in the traditional mode is avoided, the defrosting effect is good, and the user comfort experience is not influenced.

Specifically, as shown in fig. 1, an air conditioning system provided in some embodiments of the present invention includes:

an outdoor unit and an indoor unit; wherein, the indoor unit comprises an indoor heat exchanger (4); the outdoor unit comprises a compressor (5), a first reversing valve (1), an outdoor heat exchanger (3), a subcooler (7) and a gas-liquid separator (6) which are connected in series.

The D end of the first reversing valve (1) is connected with the exhaust end of the compressor (5), the E end is connected with the outdoor heat exchanger (3), the S end is connected with the inlet of the gas-liquid separator (6), and the C end is idle.

The D end of the second reversing valve (2) is connected with the exhaust end of the compressor (5), the C end of the second reversing valve is connected with the indoor heat exchanger (4), and the S end of the second reversing valve and the S end of the first reversing valve (1) are both connected with the inlet of the gas-liquid separator (6). The E end of the first reversing valve (1) is connected with the outdoor heat exchanger (3), and the E end is idle.

In the air conditioning system proposed by the present invention, the state of the condenser or the evaporator is switched to the outdoor heat exchanger (3) through the first direction valve (1), and the state of the condenser or the evaporator is switched to the indoor heat exchanger (4) through the second direction valve (2), so that the controller (not shown in the figure) switches the states of the first direction valve (1) and the second direction valve (2) and supports the operation of the whole system, such that the operation modes of the air conditioning system include but are not limited to: defrosting in a cooling mode, a heating mode and a heating mode.

As shown in fig. 2, the air conditioning system is in the cooling mode, and the controller is configured to: the first and second direction change valves (1, 2) are controlled so that the discharge side of the compressor (5) communicates with the outdoor heat exchanger (3) and the indoor heat exchanger (4) communicates with the suction side of the compressor (5). Specifically, the D end and the E end of the first reversing valve (1) are controlled to be communicated, and the C end and the S end of the second reversing valve (2) are controlled to be communicated. The compressor (5) compresses sucked low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure gas to be discharged, the high-temperature and high-pressure gas enters the outdoor heat exchanger (3) through the first reversing valve (1), heat is released in the outdoor heat exchanger (3) and is condensed into high-pressure liquid refrigerant, the high-pressure liquid refrigerant enters the subcooler (7) after being depressurized and throttled by the outdoor electronic expansion valve, the high-pressure liquid refrigerant enters the indoor heat exchanger (4) after being subcooled by the cooler (7), the high-pressure liquid refrigerant absorbs heat in the indoor heat exchanger (4) and is evaporated into gaseous refrigerant, and the gaseous refrigerant returns to the gas-liquid separator (6) through the second low-pass valve (2) and returns to the suction side of the compressor (5).

As shown in fig. 3, in the heating mode of the air conditioning system, the controller is configured to: the first and second direction change valves (1, 2) are controlled so that the discharge side of the compressor (5) communicates with the indoor heat exchanger (4) and the outdoor heat exchanger (3) communicates with the suction side of the compressor (5). Specifically, the end E of the first reversing valve (1) is controlled to be communicated with the end S, and the end D of the second reversing valve (2) is controlled to be communicated with the end C. The compressor (5) compresses sucked low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure gas to be discharged, the high-temperature and high-pressure gas enters the indoor heat exchanger (4) through the second reversing valve (2), heat is released in the indoor heat exchanger (4) and is condensed into high-pressure liquid refrigerant, the high-pressure liquid refrigerant enters the outdoor heat exchanger (3) after being subjected to pressure reduction and throttling through the indoor electronic expansion valve, the high-pressure liquid refrigerant absorbs heat in the outdoor heat exchanger (3) and is evaporated into gaseous refrigerant, and the gaseous refrigerant returns to the gas-liquid separator (6) through the first low-pass valve (1) and returns to the suction side of the compressor (5).

As shown in fig. 4, the air conditioning system starts a defrosting operation in the heating mode when the outdoor heat exchanger (3) is frosted to satisfy a defrosting condition during heating, and the controller is configured to: the second direction-changing valve (2) is maintained and the first direction-changing valve (1) is switched so that the discharge side of the compressor (1) communicates with the outdoor heat exchanger (3). Specifically, the communication state of the end D and the end C of the second reversing valve (2) is kept unchanged, the heating mode of the indoor heat exchanger (4) is kept unchanged, namely the indoor heat exchanger (4) is kept to be used as an evaporator, the first reversing valve (1) is switched to reverse, the end D is communicated with the end E, the exhaust side of the compressor (5) is communicated with the outdoor heat exchanger (3), and the outdoor heat exchanger (3) is switched to be used as a condenser from the evaporator.

A part (shown by an empty arrow in fig. 4) of the high-temperature and high-pressure refrigerant coming out of the compressor (5) enters the indoor heat exchanger (4), heat is released and condensed in the indoor heat exchanger (4), and the released heat heats the indoor space or maintains the indoor temperature; a part (as shown by black arrows in fig. 4) enters the outdoor heat exchanger (3) to be condensed and release heat, and the released heat defrosts the surface of the outdoor heat exchanger.

The refrigerant condensed by the outdoor heat exchanger (3) returns to the gas-liquid separator (6) after passing through the subcooler (7) and returns to the air suction side of the compressor (5); the refrigerant circulating from the indoor heat exchanger (4) also returns to the gas-liquid separator (6) through the subcooler (7) and returns to the air suction side of the compressor (5); in the whole defrosting process, the indoor heat exchanger (4) is still in a heating state of the condenser, the problem that the indoor environment temperature is reduced due to the fact that the indoor heat exchanger is switched into the evaporator in the traditional mode is avoided, the defrosting effect is good, and the user comfort experience is not influenced.

It should be noted that the defrosting conditions herein refer to the defrosting conditions of the conventional outdoor unit of an air conditioner, and are not a limitation of the present invention.

In the embodiment of the invention, the subcooler (7) is the existing component of the air conditioning system, and in the refrigeration mode, the subcooler (7) subcools the refrigerant condensed from the outdoor heat exchanger (3), so that the temperature of the liquid refrigerant entering the indoor heat exchanger (4) is reduced, flash gas generated during or after throttling is reduced, and the refrigeration capacity of the system is improved; in combination with the system architecture provided by the invention, a new application function is provided, during heating and defrosting operation, the refrigerant condensed from the outdoor heat exchanger (3) and the indoor heat exchanger (4) is mixed in the subcooler (7), the high-temperature refrigerant and the low-temperature refrigerant exchange heat to promote gasification and then return to the gas-liquid separator (6), and after gas-liquid separation of the gas-liquid separator (6), the gaseous refrigerant returns to the compressor (5).

That is, in the embodiment of the present invention, the cooler (7) does not perform a supercooling function during heating and defrosting, but mixes the refrigerant condensed by the outdoor heat exchanger (3) and the refrigerant condensed by the indoor heat exchanger (4) therein, and interacts with each other to exchange heat and promote vaporization, and then returns to the gas-liquid separator (6), so as to reduce the accumulation of the liquid refrigerant in the gas-liquid separator (6), avoid the influence of the suction and return of the air to the compressor on stability, and stabilize the amount of the system refrigerant, thereby ensuring heating and defrosting effects.

The following describes in detail the defrosting process of the air conditioning system in the heating mode in several embodiments.

Example one

As shown in fig. 5, the air conditioning system proposed in the present embodiment includes:

And the indoor fan (9) is operated according to the set air quantity and used for blowing hot air or cold air into the room.

An indoor electronic expansion valve (101) connected to the indoor side between the indoor heat exchanger (4) and the outdoor heat exchanger (3); and the heat exchanger is used for throttling and depressurizing the refrigerant condensed by the indoor heat exchanger (4) in the heating mode.

The air conditioning system is in a cooling mode, and the controller is configured to: the first and second direction change valves (1, 2) are controlled so that the discharge side of the compressor (5) communicates with the outdoor heat exchanger (3) and the indoor heat exchanger (4) communicates with the suction side of the compressor (5). Specifically, the D end and the E end of the first reversing valve (1) are controlled to be communicated, and the C end and the S end of the second reversing valve (2) are controlled to be communicated. The compressor (5) compresses sucked low-temperature and low-pressure gaseous refrigerants into high-temperature and high-pressure gases to be discharged, the high-temperature and high-pressure gases enter the outdoor heat exchanger (3) through the first reversing valve (1), heat is released in the outdoor heat exchanger (3) and condensed into high-pressure liquid refrigerants, the high-pressure liquid refrigerants enter the subcooler (7) after being subjected to pressure reduction and throttling through the outdoor electronic expansion valve, the high-pressure liquid refrigerants enter the indoor heat exchanger (4) after being subcooled through the chiller (7), the gaseous refrigerants absorb heat and are evaporated into gaseous refrigerants in the indoor heat exchanger (4), and the gaseous refrigerants return to the gas-liquid separator (6) through the second low-pass valve (2) and return to the suction side of the compressor (5).

In the heating mode of the air conditioning system, the controller is configured to: the first and second direction change valves (1, 2) are controlled so that the discharge side of the compressor (5) communicates with the indoor heat exchanger (4), and the outdoor heat exchanger (3) communicates with the suction side of the compressor (5). Specifically, the end E of the first reversing valve (1) is controlled to be communicated with the end S, and the end D of the second reversing valve (2) is controlled to be communicated with the end C. The compressor (5) compresses sucked low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure gas to be discharged, the high-temperature and high-pressure gas enters the indoor heat exchanger (4) through the second reversing valve (2), heat is released in the indoor heat exchanger (4) and is condensed into high-pressure liquid refrigerant, the high-pressure liquid refrigerant enters the outdoor heat exchanger (3) after being subjected to pressure reduction and throttling through the indoor electronic expansion valve (101), the high-pressure liquid refrigerant absorbs heat in the outdoor heat exchanger (3) and is evaporated into gaseous refrigerant, and the gaseous refrigerant returns to the gas-liquid separator (6) through the first low-pass valve (1) and returns to the suction side of the compressor (5).

The air conditioning system starts a defrosting operation in a heating mode when an outdoor heat exchanger (3) is frosted to meet a defrosting condition in a heating process, and the controller is configured to: the second direction change valve (2) is maintained and the first direction change valve (1) is switched so that the discharge side of the compressor (1) communicates with the outdoor heat exchanger (3). Specifically, the communication state of the end D and the end C of the second reversing valve (2) is kept unchanged, the heating mode of the indoor heat exchanger (4) is kept unchanged, namely the indoor heat exchanger (4) is kept to be used as an evaporator, the first reversing valve (1) is switched to be reversed, the end D is communicated with the end E, the exhaust side of the compressor (5) is communicated with the outdoor heat exchanger (3), and the outdoor heat exchanger (3) is switched to be used as a condenser from the evaporator.

And the controller is further configured to: adjusting the air volume of an indoor fan (9) and the opening degree of an indoor electronic expansion valve (101) to ensure that the superheat degree of a refrigerant condensed by an indoor heat exchanger (4) does not exceed a first preset superheat degree; the first preset superheat degree is required to meet the requirement that the refrigerant condensed by the indoor heat exchanger (4) is in a gas state or a gas-liquid two-phase state.

A part of high-temperature and high-pressure refrigerant from the compressor (5) enters the indoor heat exchanger (4), is released and condensed in the indoor heat exchanger (4), and heats the indoor or maintains the indoor temperature by the released heat; one part enters an outdoor heat exchanger (3) to carry out condensation and heat release, and the released heat carries out defrosting on the surface of the outdoor heat exchanger.

The refrigerant condensed by the outdoor heat exchanger (3) enters the subcooler (7), and the refrigerant condensed by the indoor heat exchanger (4) also enters the subcooler (7), in the embodiment, the superheat degree of the refrigerant condensed by the indoor heat exchanger (4) does not exceed a first preset degree through controlling the air volume of the indoor fan (9) and the opening degree of the indoor electronic expansion valve (101), so that the refrigerant condensed by the indoor heat exchanger (4) has the superheat degree but is not condensed into liquid, and a high-temperature gas state or a high-temperature gas-liquid two-phase state is maintained, so that after the refrigerant is mixed with the refrigerant entering the subcooler (7) from the indoor heat exchanger (4) in the subcooler (7), the refrigerant is gasified by the high temperature of the refrigerant, and the refrigerant entering the gas-liquid separator (6) is a gaseous refrigerant; the gaseous refrigerant returns to the suction side of the compressor (5) from the gas-liquid separator (6); in the whole defrosting process, the indoor heat exchanger (4) is still in a heating state of the condenser, the problem that the indoor environment temperature is reduced due to the fact that the indoor heat exchanger is switched to the evaporator in the traditional mode is solved, the defrosting effect is good, and the user comfort experience is not influenced.

In the embodiment, the air volume of the indoor fan (9) is adjusted, and the opening degree of the indoor electronic expansion valve (101) is adjusted, so that the superheat degree of the refrigerant condensed by the indoor heat exchanger (4) does not exceed a first preset superheat degree, for example, the indoor fan (9) is adjusted to be the minimum air volume or stopped, and specific adjustment parameters are set according to practical application conditions, which are not part limited in the embodiment.

Example two

As shown in fig. 6, the air conditioning system proposed in the present embodiment includes:

And an indoor fan (9) which is operated according to the set air volume and blows hot air during heating or cold air during cooling to the indoor.

An outdoor electronic expansion valve (102) connected to the outdoor side between the indoor heat exchanger (4) and the outdoor heat exchanger (3); the air conditioner is used for throttling and depressurizing the refrigerant condensed by the outdoor heat exchanger (3) in a refrigeration mode.

The air conditioning system is in a cooling mode, the controller is configured to: the first and second direction change valves (1, 2) are controlled so that the discharge side of the compressor (5) communicates with the outdoor heat exchanger (3) and the indoor heat exchanger (4) communicates with the suction side of the compressor (5). Specifically, the D end and the E end of the first reversing valve (1) are controlled to be communicated, and the C end and the S end of the second reversing valve (2) are controlled to be communicated. The compressor (5) compresses sucked low-temperature and low-pressure gaseous refrigerants into high-temperature and high-pressure gases to be discharged, the high-temperature and high-pressure gases enter the outdoor heat exchanger (3) through the first reversing valve (1), heat is released in the outdoor heat exchanger (3) and are condensed into high-pressure liquid refrigerants, the high-pressure liquid refrigerants enter the subcooler (7) after being subjected to pressure reduction and throttling through the outdoor electronic expansion valve (102), the high-pressure liquid refrigerants enter the indoor heat exchanger (4) after being subcooled through the cooler (7), the gaseous refrigerants absorb heat and are evaporated into gaseous refrigerants in the indoor heat exchanger (4), and the gaseous refrigerants return to the gas-liquid separator (6) through the second low-pass valve (2) and return to the air suction side of the compressor (5).

In the heating mode of the air conditioning system, the controller is configured to: the first and second direction change valves (1, 2) are controlled so that the discharge side of the compressor (5) communicates with the indoor heat exchanger (4) and the outdoor heat exchanger (3) communicates with the suction side of the compressor (5). Specifically, the end E of the first reversing valve (1) is controlled to be communicated with the end S, and the end D of the second reversing valve (2) is controlled to be communicated with the end C. The compressor (5) compresses sucked low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure gas to be discharged, the high-temperature and high-pressure gas enters the indoor heat exchanger (4) through the second reversing valve (2), heat is released in the indoor heat exchanger (4) and is condensed into high-pressure liquid refrigerant, the high-pressure liquid refrigerant enters the outdoor heat exchanger (3) after being subjected to pressure reduction and throttling through the indoor electronic expansion valve (101), the high-pressure liquid refrigerant absorbs heat in the outdoor heat exchanger (3) and is evaporated into gaseous refrigerant, and the gaseous refrigerant returns to the gas-liquid separator (6) through the first low-pass valve (1) and returns to the suction side of the compressor (5).

And the controller is further configured to: 1. adjusting the air volume of an indoor fan (9) and the opening degree of an indoor electronic expansion valve (101) to ensure that the superheat degree of a refrigerant condensed by an indoor heat exchanger (4) does not exceed a first preset superheat degree; the first preset superheat degree is required to satisfy the condition that the refrigerant condensed by the indoor heat exchanger (4) is gaseous. 2. Adjusting the opening degree of the outdoor electronic expansion valve (102) to adjust the amount of refrigerant entering the outdoor heat exchanger (3) from the exhaust side of the compressor (5), so that the superheat degree of the refrigerant condensed from the outdoor heat exchanger (3) and the refrigerant condensed from the indoor heat exchanger (4) after being mixed in the subcooler (7) does not exceed a second preset superheat degree; the second preset superheat degree needs to satisfy the condition that the mixed refrigerant is in a gas state or a gas-liquid two-phase state.

In the embodiment, the air volume of the indoor fan (9) and the opening degree of the indoor electronic expansion valve (101) are controlled, so that the superheat degree of the refrigerant condensed from the indoor heat exchanger (4) does not exceed a first preset degree, the refrigerant condensed from the indoor heat exchanger (4) has the superheat degree but is not condensed into liquid, and a high-temperature gas state or a high-temperature gas-liquid two-phase state is maintained, so that after the refrigerant is mixed with the refrigerant entering the subcooler (7) from the indoor heat exchanger (4) in the subcooler (7), the refrigerant is gasified by the high temperature of the refrigerant, and the refrigerant entering the gas-liquid separator (6) is gaseous refrigerant.

Furthermore, by combining the frosting condition and the defrosting requirement, the heat release amount of condensation at the outdoor side can be realized by adjusting the opening degree of the outdoor electronic expansion valve (102), and meanwhile, the superheat degree of the refrigerant condensed from the outdoor heat exchanger (3) and the refrigerant condensed from the indoor heat exchanger (4) after being mixed in the subcooler (7) does not exceed a second preset superheat degree, and the second preset superheat degree meets the condition that the mixed refrigerant is in a gas state or a gas-liquid two-phase state; that is, after the refrigerant condensed by the indoor heat exchanger (4) and the refrigerant condensed by the outdoor heat exchanger (3) are mixed in the subcooler (7), the former can promote the latter to be completely gasified, and the refrigerant entering the gas-liquid separator (6) is ensured to be gaseous refrigerant.

The gaseous refrigerant returns to the suction side of the compressor (5) through the gas-liquid separator (6); in the whole defrosting process, the indoor heat exchanger (4) is still in a heating state of the condenser, the problem that the indoor environment temperature is reduced due to the fact that the indoor heat exchanger is switched into the evaporator in the traditional mode is avoided, the defrosting effect is good, and the user comfort experience is not influenced.

In this embodiment, the air volume of the indoor fan (9) is adjusted, and the opening degree of the indoor electronic expansion valve (101) is adjusted, so that the superheat degree of the refrigerant condensed by the indoor heat exchanger (4) does not exceed a first preset superheat degree as a reference, for example, the indoor fan (9) is adjusted to be the minimum air volume or stopped, and specific adjustment parameters are set according to actual application conditions, which are not part limited in this embodiment. Similarly, the opening degree of the outdoor electronic expansion valve (102) is adjusted so that the superheat degree of the refrigerant condensed by the outdoor heat exchanger (3) and the refrigerant condensed by the indoor heat exchanger (04) after being mixed in the subcooler (7) does not exceed a second preset superheat degree as a reference, and specific adjustment parameters are set according to practical application conditions, but are not limited in the embodiment.

Typically, the second predetermined degree of superheat does not exceed the first predetermined degree of superheat.

EXAMPLE III

As shown in fig. 7, the air conditioning system proposed in the present embodiment includes:

An outdoor electronic expansion valve (102) connected to the outdoor side between the indoor heat exchanger (4) and the outdoor heat exchanger (3); the refrigerant condensing device is used for throttling and depressurizing the refrigerant condensed by the outdoor heat exchanger (3) in the refrigeration mode.

And an EVB expansion valve (103) which is installed on a supercooling branch between the outdoor heat exchanger (3) and the subcooler (7). Generally, in a refrigeration mode, a part of refrigerant condensed by the outdoor heat exchanger (3) enters the subcooler (7) from the end e, is discharged from the end g after being subcooled and enters the main refrigeration loop of the indoor heat exchanger (4), and a part of refrigerant passes through the cold branch and enters the subcooler (7) from the end f, is discharged from the end h after heat exchange and returns to the air suction side of the compressor (5) after passing through the gas-liquid separator (6).

The air conditioning system is in a cooling mode, and the controller is configured to: the first and second direction change valves (1, 2) are controlled so that the discharge side of the compressor (5) communicates with the outdoor heat exchanger (3) and the indoor heat exchanger (4) communicates with the suction side of the compressor (5). Specifically, the D end and the E end of the first reversing valve (1) are controlled to be communicated, and the C end and the S end of the second reversing valve (2) are controlled to be communicated. The compressor (5) compresses sucked low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure gas to be discharged, the high-temperature and high-pressure gas enters the outdoor heat exchanger (3) through the first reversing valve (1), heat is released in the outdoor heat exchanger (3) and is condensed into high-pressure liquid refrigerant, the high-pressure liquid refrigerant is decompressed and throttled by the outdoor electronic expansion valve (102), one part of the high-pressure liquid refrigerant enters the subcooler (7) from the end e, the high-pressure liquid refrigerant is discharged from the end g after being subcooled and enters the main refrigeration loop of the indoor heat exchanger (4), the high-pressure liquid refrigerant absorbs heat in the indoor heat exchanger (4) and is evaporated into gaseous refrigerant, and the gaseous refrigerant returns to the gas-liquid separator (6) through the second low-way valve (2) and returns to the air suction side of the compressor (5); and one part of the gas enters the subcooler (7) from the end f through the cold branch, is discharged from the end h after heat exchange, and returns to the suction side of the compressor (5) through the gas-liquid separator (6).

The air conditioning system starts a defrosting operation in a heating mode when an outdoor heat exchanger (3) is frosted in a heating process and a defrosting condition is met, and the controller is configured to: the second direction-changing valve (2) is maintained and the first direction-changing valve (1) is switched so that the discharge side of the compressor (1) communicates with the outdoor heat exchanger (3). Specifically, the communication state of the end D and the end C of the second reversing valve (2) is kept unchanged, the heating mode of the indoor heat exchanger (4) is kept unchanged, namely the indoor heat exchanger (4) is kept to be used as an evaporator, the first reversing valve (1) is switched to reverse, the end D is communicated with the end E, the exhaust side of the compressor (5) is communicated with the outdoor heat exchanger (3), and the outdoor heat exchanger (3) is switched to be used as a condenser from the evaporator.

In this embodiment, the controller is further configured to: 1. the opening degree of the EVB expansion valve (103) is adjusted according to defrosting requirements, frosting amount and the like, and the amount of refrigerant entering the outdoor heat exchanger (3) is adjusted together with the adjustment of the opening degree of the outdoor electronic expansion valve (102), so that the defrosting effect of the outdoor heat exchanger (3) is improved.

Meanwhile, 2, the air volume of the indoor fan (9) and the opening degree of the indoor electronic expansion valve (101) are adjusted, so that the superheat degree of the refrigerant condensed by the indoor heat exchanger (4) does not exceed a first preset superheat degree; the first preset superheat degree is required to meet the condition that the refrigerant condensed by the indoor heat exchanger (4) is in a gas state or a gas-liquid two-phase state. 3. Adjusting the opening degree of the outdoor electronic expansion valve (102) to adjust the amount of refrigerant entering the outdoor heat exchanger (3) from the exhaust side of the compressor (5), so that the superheat degree of the refrigerant condensed from the outdoor heat exchanger (3) and the refrigerant condensed from the indoor heat exchanger (4) after being mixed in the subcooler (7) does not exceed a second preset superheat degree; the second preset superheat degree is required to meet the requirement that the mixed refrigerant is in a gas state or a gas-liquid two-phase state.

A part of high-temperature and high-pressure refrigerant from the compressor (5) enters the indoor heat exchanger (4), is released and condensed in the indoor heat exchanger (4), and the released heat heats the indoor space or maintains the indoor temperature; one part enters an outdoor heat exchanger (3) to carry out condensation and heat release, and the released heat carries out defrosting on the surface of the outdoor heat exchanger.

The refrigerant condensed in the outdoor heat exchanger (3) enters the subcooler (7), the refrigerant condensed in the indoor heat exchanger (4) also enters the subcooler (7), the superheat degree of the refrigerant condensed in the indoor heat exchanger (4) does not exceed a first preset superheat degree through the air volume control of the indoor fan (9) and the opening degree control of the indoor electronic expansion valve (101), so that the refrigerant condensed in the indoor heat exchanger (4) has the superheat degree but is not condensed into liquid, and a high-temperature gas state or a high-temperature gas-liquid two-phase state is maintained, so that after the refrigerant is mixed with the refrigerant entering the subcooler (7) from the indoor heat exchanger (4) in the subcooler (7), the refrigerant is gasified at the high temperature, and the refrigerant entering the gas-liquid separator (6) is a gaseous refrigerant or a gas-liquid two-phase state.

Furthermore, the condensation heat release quantity at the outdoor side is realized by adjusting the opening degree of an outdoor electronic expansion valve (102) and/or an EVB expansion valve (103) in combination with the frosting condition and the defrosting requirement, and meanwhile, the superheat degree of the refrigerant condensed from the outdoor heat exchanger (3) and the refrigerant condensed from the indoor heat exchanger (4) after being mixed in the subcooler (7) does not exceed a second preset superheat degree, and the second preset superheat degree meets the condition that the mixed refrigerant is in a gas state or a gas-liquid two-phase state; that is, after the refrigerant condensed by the indoor heat exchanger (4) and the refrigerant condensed by the outdoor heat exchanger (3) are mixed in the subcooler (7), the former can promote the latter to be gasified, and the refrigerant entering the gas-liquid separator (6) is ensured to be completely in a gas state or a gas-liquid two-phase state.

The gaseous refrigerant returns to the suction side of the compressor (5) from the gas-liquid separator (6); in the whole defrosting process, the indoor heat exchanger (4) is still in a heating state of the condenser, the problem that the indoor environment temperature is reduced due to the fact that the indoor heat exchanger is switched into the evaporator in the traditional mode is avoided, the defrosting effect is good, and the user comfort experience is not influenced.

In the embodiment, a supercooling branch where the EVB expansion valve (103) is located is not used as a supercooling branch, but used as a refrigerant loop of the outdoor heat exchanger (3), when the air conditioning system operates in a heating mode and needs defrosting, the outdoor heat exchanger (3) is switched from an evaporator to a condenser for use, and in combination with a frosting condition, the amount of refrigerant entering the outdoor heat exchanger (3) can be adjusted by adjusting the opening degree of the EVB expansion valve (103), and the defrosting effect is improved based on different amounts of refrigerant; when the frost formation amount is small, the opening degree of the EVB expansion valve (103) is adjusted to be small, and when the frost formation amount is large, the opening degree of the EVB expansion valve (93) is adjusted to be large.

Example four

As shown in fig. 8, the air conditioning system proposed in the present embodiment includes:

And the compressor bypass branch is arranged between the exhaust side of the compressor (5) and the inlet of the gas-liquid separator (6) and is formed by connecting a bypass electromagnetic valve (111) and a bypass capillary tube (112) in series.

The air conditioning system is in a cooling mode, and the controller is configured to: the first and second direction change valves (1, 2) are controlled so that the discharge side of the compressor (5) communicates with the outdoor heat exchanger (3) and the indoor heat exchanger (4) communicates with the suction side of the compressor (5). Specifically, the D end and the E end of the first reversing valve (1) are controlled to be communicated, and the C end and the S end of the second reversing valve (2) are controlled to be communicated. The compressor (5) compresses sucked low-temperature and low-pressure gaseous refrigerant into high-temperature and high-pressure gas to be discharged, the high-temperature and high-pressure gas enters the outdoor heat exchanger (3) through the first reversing valve (1), heat is released in the outdoor heat exchanger (3) and is condensed into high-pressure liquid refrigerant, the high-pressure liquid refrigerant is subjected to pressure reduction and throttling through the outdoor electronic expansion valve (102), one part of the high-pressure liquid refrigerant enters the subcooler (7) from the e end, the high-pressure liquid refrigerant is discharged from the g end after being subcooled and enters the main refrigeration loop of the indoor heat exchanger (4), the high-pressure liquid refrigerant absorbs heat and is evaporated into gaseous refrigerant in the indoor heat exchanger (4), and the gaseous refrigerant returns to the gas-liquid separator (6) through the second low-way valve (2) and returns to the air suction side of the compressor (5); and one part of the gas enters the subcooler (7) from the end f through the cold branch, is discharged from the end h after heat exchange, and returns to the suction side of the compressor (5) through the gas-liquid separator (6).

For the specific configuration of the indoor fan (9), the indoor electronic expansion valve (101), the outdoor electronic expansion valve (102), and the EVB electronic expansion valve (103), the controller refers to the first to third embodiments, which are not described in detail in this embodiment.

And a large amount of liquid refrigerants are generated in the outdoor heat exchanger (3) and the gas-liquid separator (6) in the defrosting process under the whole heating mode, so that the exhaust pressure, the suction pressure, the exhaust temperature and the like in the air conditioning system are lower than corresponding target values, and the controller is also configured to: whether the bypass electromagnetic valve (111) is closed to be communicated with the bypass branch of the compressor is determined according to the overheat state of the air suction of the compressor (5), the bypass electromagnetic valve (111) is closed to be communicated with the bypass branch of the compressor, so that the high-temperature and high-pressure refrigerant discharged by the compressor (5) enters the gas-liquid separator (6) to promote the gasification of the liquid refrigerant, the refrigerant suction amount of the compressor (5) is increased, the influence on the reliability of the compressor (5) due to the air suction and liquid return of the compressor is avoided, and the stability and reliability of the operation of the unit are ensured.

EXAMPLE five

As shown in fig. 9, the air conditioning system proposed in the present embodiment includes:

And an indoor fan (9) which is operated according to the set air quantity and blows hot air during heating or cold air during cooling to the indoor.

And an EVB expansion valve (103) which is installed on a supercooling branch between the outdoor heat exchanger (3) and the subcooler (7). In a refrigeration mode, part of refrigerant condensed from the outdoor heat exchanger (3) enters the subcooler (7) from the end e, is discharged from the end g after being subcooled, enters the main refrigeration loop of the indoor heat exchanger (4), and part of refrigerant enters the subcooler (7) from the end f through the cold branch, is discharged from the end h after heat exchange, and returns to the air suction side of the compressor (5) after passing through the gas-liquid separator (6).

Above-mentioned, the off-premises station still includes three refrigerant pipelines: a high pressure gas line (121), a low pressure gas line (122) and a liquid return line (123); wherein, the high-pressure air pipeline (121) and the low-pressure air pipeline (122) are both connected to the exhaust side of the compressor (5), and the liquid return pipeline (123) is connected to the suction side of the compressor (5).

The indoor unit includes: a cold-heat converter (13) connected between the high-pressure air pipe (121) and the low-pressure air pipe (122) of the outdoor unit and the indoor heat exchanger (4); as shown in fig. 10, the cold-heat converter (13) includes expansion valves (151) and (152) for controlling the opening and closing of the high-pressure air line (121), expansion valves (153) and (154) for controlling the opening and closing of the low-pressure air line (122), and a bypass capillary tube (155) between the high-pressure air line (121) and the low-pressure air line (122).

In this embodiment, the number of the indoor units is plural, and some or all of the indoor units are connected to the cooling/heating converter (13) through respective indoor air pipes (14). The cold-hot converter (13) is connected in parallel between the high-pressure air pipeline (121) and the low-pressure air pipeline (122) of the outdoor unit and the indoor heat exchanger (4).

When the air conditioning system is operated in a heating mode or a defrosting mode, the controller is configured to: the expansion valves (151) and (152) on the high-pressure air pipe (121) side are controlled to be opened, the expansion valves (153) and (154) on the low-pressure air pipe (122) side are controlled to be closed, and the indoor air pipe (14) is connected with the high-pressure air pipe (121).

When the air conditioning system is operating in a cooling mode, the controller is configured to: the expansion valves (153) and (154) on the low-pressure air pipe (122) side are controlled to be opened, the expansion valves (151) and (152) on the high-pressure air pipe (131) side are controlled to be closed, and the indoor air pipe (14) is connected with the low-pressure air pipe (122).

For the specific configuration of the indoor fan (9), the indoor electronic expansion valve (101), the outdoor electronic expansion valve (102), the EVB electronic expansion valve (103), the compressor bypass branch, etc., the controller refers to the first to fourth embodiments, which are not described in detail in this embodiment.

Example six

In this embodiment, on the basis of any of the above embodiments, as shown in fig. 11, the C end and the S end of the first direction valve (1) are short-circuited through the first capillary (81); and/or the end E and the end S of the second reversing valve (2) are in short circuit through a second capillary tube (82).

Because no matter in the process of heating or in the process of heating and defrosting, the first reversing valve (1) does not need to be reversed, refrigerant liquid can be accumulated at the idle end of the first reversing valve (1), in order to ensure that the first reversing valve (1) can not be smoothly blocked by liquid refrigerants in the reversing process, a first capillary tube (81) is additionally arranged between the C end and the S end of the first reversing valve, the accumulated refrigerants are bypassed to a gas-liquid separator (6) by the first capillary tube (81), and the situation that the accumulated refrigerant liquid blocks the reversing of the first reversing valve (1) is avoided. Similarly, in some embodiments of the invention, since the second reversing valve (2) does not need to reverse in the refrigeration process, the second reversing valve (2) may accumulate refrigerant liquid at the idle end, in order to ensure that the second reversing valve (2) does not have liquid refrigerant obstruction in the reversing process, a second capillary tube (82) is added between the end E and the end S, and the second capillary tube (82) bypasses the accumulated refrigerant to the gas-liquid separator (6), thereby preventing the accumulated refrigerant liquid from obstructing the reversing of the second reversing valve (2).

In the foregoing description of embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.

Claims

1. An air conditioning system comprising:

it is characterized by also comprising:

a second reversing valve (2) which is arranged in the outdoor unit and used for switching the state of the condenser or the state of the evaporator of the indoor heat exchanger (4);

a controller configured to:

when the air conditioning system operates in a heating mode and needs defrosting, maintaining the second reversing valve (2) and controlling the first reversing valve (1) to reverse, so that the indoor heat exchanger (4) is maintained as a condenser to perform heating, and the outdoor heat exchanger (3) is switched to be used as the condenser to perform defrosting; the refrigerant after heat release by the indoor heat exchanger (4) and the refrigerant after heat release by the outdoor heat exchanger (3) are mixed for heat exchange and gasification and then return to the suction side of the compressor.

2. The air conditioning system of claim 1,

the outdoor unit consists of a compressor (5), a first reversing valve (1), an outdoor heat exchanger (3), a subcooler (7) and a gas-liquid separator (6) which are connected in series;

the D end of the second reversing valve (2) and the D end of the first reversing valve (1) are both connected with the exhaust end of the compressor (5), the C end of the second reversing valve is connected with the indoor heat exchanger (4), and the S end of the second reversing valve and the S end of the first reversing valve (1) are both connected with the inlet of the gas-liquid separator (6); the E end of the first reversing valve (1) is connected with the outdoor heat exchanger (3);

the controller is configured to:

when the air conditioning system operates in a heating mode, controlling the first reversing valve (1) and the second reversing valve (2) to enable the exhaust side of the compressor (5) to be communicated with the indoor heat exchanger (4) and the outdoor heat exchanger (3) to be communicated with the suction side of the compressor (5);

when the air conditioning system is operated in a heating mode and defrosting is needed, the second reversing valve (2) is maintained and the first reversing valve (1) is switched, so that the exhaust side of the compressor (1) is communicated with the outdoor heat exchanger (3).

3. The air conditioning system of claim 2, wherein the indoor unit further comprises:

an indoor fan (9);

an indoor electronic expansion valve (101) connected to the indoor side between the indoor heat exchanger (4) and the outdoor heat exchanger (3);

the controller is configured to: when the air conditioning system runs in a heating mode and needs defrosting, adjusting the air volume of the indoor fan (9) and the opening degree of the indoor electronic expansion valve (101) to ensure that the superheat degree of a refrigerant condensed by the indoor heat exchanger (4) does not exceed a first preset superheat degree;

the first preset superheat degree meets the condition that the refrigerant condensed by the indoor heat exchanger (4) is in a gas state or a gas-liquid two-phase state.

4. The air conditioning system of claim 3, wherein the outdoor unit further comprises:

an outdoor electronic expansion valve (102) connected to the outdoor side between the indoor heat exchanger (4) and the outdoor heat exchanger (3);

the controller is configured to: when the air conditioning system operates in a heating mode and needs defrosting, adjusting the opening degree of the outdoor electronic expansion valve (102) to adjust the amount of refrigerant entering the outdoor heat exchanger (3) from the exhaust side of the compressor (5), so that the superheat degree of the refrigerant condensed from the outdoor heat exchanger (3) and the refrigerant condensed from the indoor heat exchanger (4) after being mixed in the subcooler (7) does not exceed a second preset superheat degree; the second preset superheat degree meets the condition that the mixed refrigerant is in a gas state or a gas-liquid two-phase state.

5. The air conditioning system of claim 4, wherein the outdoor unit further comprises:

an EVB expansion valve (103) which is installed on a supercooling branch between the outdoor heat exchanger (3) and the subcooler (7);

the controller is configured to: when the air conditioning system is operated in a heating mode and needs defrosting, the opening degree of the outdoor electronic expansion valve (102) and the opening degree of the EVB expansion valve (103) are adjusted according to defrosting requirements so as to adjust the quantity of refrigerants entering the outdoor heat exchanger (3).

6. The air conditioning system of claim 1, wherein the outdoor unit further comprises:

the compressor bypass branch is arranged between the exhaust side of the compressor (5) and the inlet of the gas-liquid separator (6) and is formed by connecting a bypass electromagnetic valve (111) and a bypass capillary tube (112) in series;

the controller is configured to: when the air conditioning system is operated in a heating mode and defrosting is needed, whether the bypass solenoid valve (111) is closed to communicate with the compressor bypass branch is determined according to the overheat state of the air suction of the compressor (5).

7. The air conditioning system of claim 1, wherein the outdoor unit further comprises three refrigerant lines: a high pressure gas line (121), a low pressure gas line (122) and a liquid return line (123); wherein the high-pressure gas pipeline (121) and the low-pressure gas pipeline (122) are both connected to the exhaust side of the compressor (5), and the liquid return pipeline (123) is connected to the suction side of the compressor (5);

the indoor unit further includes:

a cold/heat converter (13) connected between the high-pressure gas line (121) and the low-pressure gas line (122) of the outdoor unit and the indoor heat exchanger (4); the device comprises an expansion valve for controlling the on-off of a high-pressure air pipeline (121) and a low-pressure air pipeline (122), and a bypass capillary tube between the high-pressure air pipeline (121) and the low-pressure air pipeline (122);

the controller is configured to: when the air conditioning system operates in a heating mode or defrosting mode, the expansion valve on the side of the high-pressure air pipeline (121) is controlled to be opened, the expansion valve on the side of the low-pressure air pipeline (122) is controlled to be closed, and an air pipe of an indoor unit is connected with the high-pressure air pipeline (121).

8. Air conditioning system according to claim 1, characterized in that the C and S ends of the first directional control valve (1) are short-circuited by a first capillary tube (81).

9. Air conditioning system according to claim 1, characterized in that the E and S ends of the second directional control valve (2) are short-circuited by a second capillary tube (82).

10. The multi-split air conditioning system as claimed in claim 2, wherein the controller is configured to:

when the air conditioning system operates in a heating mode, controlling the end E of the first reversing valve (1) to be communicated with the end S, and controlling the end D of the second reversing valve (2) to be communicated with the end C;

when the air conditioning system runs in a heating mode and needs defrosting, the D end and the C end of the second reversing valve (2) are maintained to be communicated, and the D end and the E end of the first reversing valve (1) are switched to be communicated.