CN112013515B

CN112013515B - Control method of air conditioner

Info

Publication number: CN112013515B
Application number: CN201910468311.3A
Authority: CN
Inventors: 雷俊杰; 张�浩; 黎顺全; 王正兴
Original assignee: Midea Group Co Ltd; GD Midea Air Conditioning Equipment Co Ltd
Current assignee: Midea Group Co Ltd; GD Midea Air Conditioning Equipment Co Ltd
Priority date: 2019-05-30
Filing date: 2019-05-30
Publication date: 2022-02-11
Anticipated expiration: 2039-05-30
Also published as: CN112013515A

Abstract

The invention discloses a control method of an air conditioner, which comprises the following steps: under a constant temperature dehumidification mode, obtaining the reheating supercooling degree of a refrigerant outflow end of a reheating heat exchanger; comparing the reheating supercooling degree with the reheating target supercooling degree; if the reheating supercooling degree is greater than the reheating target supercooling degree, increasing the opening degree of a reheating regulating valve; if the reheating supercooling degree is smaller than the reheating target supercooling degree, reducing the opening degree of a reheating regulating valve; and if the reheating supercooling degree is equal to the reheating target supercooling degree, keeping the opening degree of the reheating regulating valve. The technical scheme of the invention is beneficial to improving the effect of the constant temperature dehumidification mode.

Description

Control method of air conditioner

Technical Field

The invention relates to the technical field of air conditioners, in particular to a control method of an air conditioner.

Background

Due to the complexity of weather, the air conditioner needs to have multiple functions at the same time to meet the requirements of people. For example, in order to overcome the weather with very high humidity, it is necessary for an air conditioner to have a dehumidifying function. However, in the existing air conditioner with dehumidification function, the supercooling degree of the indoor heat exchanger is unreasonable in the process of constant temperature dehumidification, so that the constant temperature dehumidification effect of the indoor heat exchanger in the constant temperature dehumidification mode is poor.

Disclosure of Invention

The invention mainly aims to provide a control method of an air conditioner, aiming at improving the constant temperature dehumidification effect.

In order to achieve the purpose, the invention provides a control method of an air conditioner, the air conditioner comprises an outdoor unit and an indoor unit, the outdoor unit comprises a compression mechanism and an outdoor heat exchanger, and the indoor unit comprises a dehumidification heat exchanger and a dehumidification throttling regulation device;

the air conditioner further includes: a discharge pipe connected to a discharge side of the compression mechanism, a low-pressure suction pipe connected to a low-pressure suction side of the compression mechanism, a liquid-side piping connecting the discharge pipe, the outdoor heat exchanger, the dehumidification throttle control device, and the dehumidification heat exchanger in this order, and a gas-side piping connecting the dehumidification heat exchanger and the low-pressure suction pipe, thereby constituting a dehumidification circuit;

the indoor unit also comprises a reheating heat exchanger, a reheating throttling regulation device and a heat circulation device for sending the heat or cold of the indoor unit into the room;

the air conditioner further includes a high-low pressure pipe and a branch pipe branching from the discharge pipe, the high-low pressure pipe sequentially connecting a first intersection of the liquid-side pipe, the reheat throttle control device, the reheat heat exchanger, and the branch pipe to constitute a reheat circuit, wherein the first intersection is located between the dehumidification throttle control device and the outdoor heat exchanger;

the control method of the air conditioner comprises the following steps:

the indoor unit and the outdoor unit are both in a constant-temperature dehumidification mode, and the reheating supercooling degree of the refrigerant outflow end of the reheating heat exchanger is obtained;

comparing the reheating supercooling degree with the reheating target supercooling degree;

if the reheating supercooling degree is smaller than the reheating target supercooling degree, reducing the opening degree of a reheating regulating valve;

if the reheating supercooling degree is greater than the reheating target supercooling degree, increasing the opening degree of a reheating regulating valve;

and if the reheating supercooling degree is equal to the reheating target supercooling degree, keeping the opening degree of the reheating regulating valve.

Optionally, the air conditioner further comprises a gas-liquid separator and an economizer, wherein the gas-liquid separator is arranged on the low-pressure suction pipe; the economizer is arranged on a liquid side pipe between the outdoor heat exchanger and the first intersection point, and a return pipe of the economizer is communicated with the gas-liquid separator; the economizer is internally provided with a first refrigerant flow path and a second refrigerant flow path, and two ends of the first refrigerant flow path are respectively communicated with liquid side distribution pipes at two ends of the economizer; one end of the second refrigerant flow path is communicated with the liquid side pipe through a liquid taking pipe, and the other end of the second refrigerant flow path is communicated with a medium-pressure suction inlet of the compressor through a return pipe; a liquid taking throttle valve is arranged on the liquid taking pipe;

if the reheating supercooling degree is greater than the reheating target supercooling degree, the specific step of increasing the opening degree of the reheating throttling regulation device comprises the following steps:

if the reheating supercooling degree is greater than the reheating target supercooling degree;

acquiring the current opening degree of the reheating throttling adjusting device, and comparing the current opening degree with a target opening degree range;

and if the current opening degree is smaller than the maximum value of the target opening degree range, increasing the opening degree of the reheating throttle adjusting device.

Optionally, after the step of obtaining the current opening degree of the reheat throttle adjusting device and comparing the current opening degree with the target opening degree range, the method further comprises:

and if the current opening is larger than or equal to the maximum value of the target opening range, adjusting the opening of the outdoor side throttling adjusting device to reduce the reheating supercooling degree.

Optionally, if the reheat supercooling degree is smaller than the reheat target supercooling degree, the specific step of reducing the opening degree of the reheat throttling regulation device includes:

if the reheating supercooling degree is smaller than the reheating target supercooling degree;

and if the current opening degree is larger than the minimum value of the target opening degree range, reducing the opening degree of the reheating throttle adjusting device.

and if the current opening is smaller than or equal to the minimum value of the target opening range, adjusting the opening of the liquid-taking throttle valve to increase the reheating supercooling degree.

Optionally, the return pipe is communicated with the gas-liquid separator through a low-pressure suction pipe, and a second control valve is arranged on the return pipe or a connecting pipe between the return pipe and the low-pressure suction pipe.

Optionally, the air conditioner further comprises an economizer; the economizer is arranged on a liquid side pipe between the outdoor heat exchanger and the first intersection point, and a return pipe of the economizer is communicated with a medium-pressure suction inlet of the compressor; the economizer is internally provided with a first refrigerant flow path and a second refrigerant flow path, and two ends of the first refrigerant flow path are respectively communicated with liquid side distribution pipes at two ends of the economizer; one end of the second refrigerant flow path is communicated with the liquid side pipe through a liquid taking pipe, and the other end of the second refrigerant flow path is communicated with a medium-pressure suction inlet of the compressor through a return pipe; and a liquid taking throttle valve is arranged on the liquid taking pipe.

Optionally, the inflow end of the liquid taking pipe is communicated with a liquid side pipe between the economizer and the outdoor side heat exchanger; alternatively, the first and second electrodes may be,

the inflow end of the liquid take-off pipe is communicated with a liquid side pipe between the economizer and the first intersection.

Optionally, the outdoor unit further comprises a first switch switchable between a first switch first switching state and a first switch second switching state,

in the first switching state, the first switch communicates the liquid-side pipe with the suction pipe and communicates the gas-side pipe with the discharge pipe,

in the second switching state, the first switch communicates the liquid-side pipe with the discharge pipe and communicates the gas-side pipe with the suction pipe.

Optionally, the air conditioner further comprises a second switch capable of switching between a third switching state and a fourth switching state of the second switch,

in the third switching state, the second switch communicates the high-low pressure pipe with the branch pipe,

in the fourth switching state, the second switch connects the high-low pressure pipe and the suction pipe.

Optionally, the control method of the air conditioner further includes:

acquiring the dehumidification refrigeration superheat degree of a refrigerant outflow port of a dehumidification heat exchanger;

comparing the dehumidification refrigeration superheat degree with the dehumidification refrigeration target superheat degree;

if the superheat degree of dehumidification refrigeration is smaller than the target superheat degree of dehumidification refrigeration, reducing the opening degree of the dehumidification throttling adjusting device;

if the dehumidification refrigeration superheat degree is larger than the dehumidification refrigeration target superheat degree, the opening degree of the dehumidification throttling adjusting device is increased;

and if the supercooling degree of the dehumidification refrigeration is equal to the target supercooling degree of the dehumidification refrigeration, keeping the opening degree of the dehumidification throttling adjusting device.

Optionally, the method further includes, before the step of obtaining the reheat supercooling degree of the refrigerant outflow end of the reheat heat exchanger, the steps of:

detecting the opening degree adjusting condition of the dehumidification throttling adjusting device;

if the dehumidification throttling regulation device is adjusting the opening degree, the reheating and supercooling degree of the refrigerant outflow end of the reheating heat exchanger is not acquired;

and if the opening degree of the dehumidification throttling adjusting device is not adjusted, acquiring the reheating and supercooling degree of the refrigerant outflow end of the reheating heat exchanger.

Optionally, the opening degree of the dehumidification throttle adjusting device and the opening degree of the reheating throttle device are alternately adjusted.

the method comprises the following steps of obtaining the reheat supercooling degree of the refrigerant outflow end of the reheat heat exchanger before the step of obtaining the reheat supercooling degree of the refrigerant outflow end of the reheat heat exchanger:

detecting the opening degree adjusting condition of the outdoor side throttling adjusting device;

if the opening degree of the outdoor side throttling regulation device is adjusted, the reheating and supercooling degree of the refrigerant outflow end of the reheating heat exchanger is not acquired;

and if the opening degree of the outdoor side throttling regulation device is not adjusted, acquiring the reheating and supercooling degree of the refrigerant outflow end of the reheating heat exchanger.

According to the technical scheme, in a constant-temperature dehumidification mode, the reheating supercooling degree of the refrigerant outflow end of the reheating heat exchanger is firstly obtained; then comparing the reheating supercooling degree with the reheating target supercooling degree; then, if the reheating supercooling degree is greater than the reheating target supercooling degree, reducing the opening degree of a reheating regulating valve; if the reheating supercooling degree is smaller than the reheating target supercooling degree, increasing the opening degree of a reheating regulating valve; if the reheating supercooling degree is equal to the reheating target supercooling degree, keeping the opening degree of the reheating regulating valve; the reheating throttle valve has proper opening degree under the constant temperature dehumidification mode, the reheating supercooling degree of the reheating heat exchanger of the air conditioner is effectively adjusted, the supercooling degree of the reheating heat exchanger under the constant temperature dehumidification mode is ensured, and the reheating effect of the reheating heat exchanger is ensured.

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 the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a heating mode of an air conditioner according to a second embodiment of the present invention;

FIG. 2 is a schematic view showing the internal structure of the economizer shown at A in FIG. 1;

FIG. 3 is a schematic structural diagram of an air conditioner according to a next embodiment of the present invention in a cooling mode;

FIG. 4 is a schematic structural diagram of an air conditioner in a constant temperature dehumidification mode according to an embodiment of the present invention;

FIG. 5 is a flowchart illustrating an embodiment of a method for controlling an air conditioner according to the present invention;

FIG. 6 is a flow chart illustrating a control method of an air conditioner according to another embodiment of the present invention;

FIG. 7 is a flow chart illustrating a control method of an air conditioner according to another embodiment of the present invention;

FIG. 8 is a flow chart illustrating a control method of an air conditioner according to still another embodiment of the present invention;

FIG. 9 is a schematic structural diagram of an air conditioner according to another embodiment of the present invention in a cooling mode;

FIG. 10 is a schematic structural diagram of another embodiment of the air conditioner of the present invention in a heating mode;

FIG. 11 is a schematic structural diagram of an air conditioner according to another embodiment of the present invention in a constant temperature dehumidification mode;

FIG. 12 is a schematic diagram of an air conditioner indoor unit of the present invention having a total demand for cooling capacity greater than a total demand for heating capacity;

FIG. 13 is a schematic diagram of the total cooling capacity requirement of the indoor units of the air conditioner of the present invention being equal to the total heating capacity requirement;

FIG. 14 is a schematic diagram of an air conditioner indoor unit having a total demand for cooling less than a total demand for heating in accordance with the present invention;

FIG. 15 is a schematic structural diagram of a constant temperature dehumidification mode of an air conditioner according to another embodiment of the present invention.

The reference numbers illustrate:

the implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

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 invention.

It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.

The specific structure of the air conditioner will be mainly described below.

Referring to fig. 1 to 8, first, the entire piping structure and component arrangement of the air conditioner will be described; in the embodiment of the present invention, the air conditioner includes an outdoor unit 100 and an indoor unit 200, the outdoor unit 100 includes an enthalpy-increasing compressor 110 and an outdoor heat exchanger 141, the indoor unit 200 includes a dehumidifying heat exchanger 220 and a dehumidifying throttle adjusting device 240;

the air conditioner further includes: a discharge pipe 111 connected to a discharge side of the compressor 110, a low-pressure suction pipe 113 connected to a low-pressure suction side of the compressor 110, a liquid-side pipe 140 connecting the discharge pipe 111, the outdoor heat exchanger 141, the dehumidification throttle control device 240, and the dehumidification heat exchanger 220 in this order, and a gas-side pipe 150 connecting the dehumidification heat exchanger 220 and the low-pressure suction pipe 113, thereby forming a dehumidification circuit;

the indoor unit 200 further includes a reheat heat exchanger 210, a reheat throttle adjusting device 230, and a heat cycle device for sending heat or cold of the indoor unit 200 into the room;

the air conditioner further includes a high-low pressure pipe 160 and a branch pipe 112 branched from the discharge pipe 111, wherein the high-low pressure pipe 160 forms a reheat circuit by sequentially connecting a first intersection 211 of the liquid side pipe 140, the reheat throttle control device 230, the reheat heat exchanger 210, and the branch pipe 112, and the first intersection 211 is located between the dehumidification throttle control device 240 and the outdoor heat exchanger 141.

The heat cycle device can be a wind wheel in some embodiments, and the wind wheel rotates to convey air after heat exchange with the initial heat exchanger and the reheating heat exchanger to the indoor. Of course, in other embodiments, the heat cycle device may also be a water cycle device, and the dehumidification heat exchanger and the reheat heat exchanger send heat or cold to the indoor through the circulating water flowing in the water cycle device.

On the basis of the pipelines, the dehumidification heat exchanger 220 of the air conditioner refrigerates, and the reheating heat exchanger 210 heats, so that constant-temperature dehumidification can be realized. Wherein the dehumidification throttle adjusting device 240 comprises a dehumidification throttle valve, and the reheat throttle adjusting device 230 comprises a reheat throttle valve.

In some embodiments, the outdoor unit 100 further comprises a first switch 131, the first switch 131 being switchable between a first switching state of the first switch 131 and a second switching state of the first switch 131,

in the first switching state, the first switch 131 communicates the liquid-side pipe 140 with the suction pipe and communicates the gas-side pipe 150 with the discharge pipe 111, and in the second switching state, the first switch 131 communicates the liquid-side pipe 140 with the discharge pipe 111 and communicates the gas-side pipe 150 with the suction pipe.

Through the setting of the first switch 131, in the first switching state, the air conditioner is in the heating state, that is, the dehumidifying heat exchanger 220 and the reheating heat exchanger 210 simultaneously heat; and in the second switching state, the air conditioner is in a constant-temperature dehumidification state. The first switch 131 may be a four-way valve.

In some other embodiments, the air conditioner further includes a second switch 132, wherein the second switch 132 is switchable between a third switching state of the second switch 132, in which the second switch 132 communicates the high-low pressure pipe 160 with the branch pipe 112, and a fourth switching state, in which the second switch 132 communicates the high-low pressure pipe 160 with the suction pipe.

By setting the second switch 132, in the third switching state, the air conditioner is in the constant temperature dehumidification state; in the fourth switching state, the air conditioner is in a cooling state, that is, the dehumidifying heat exchanger 220 and the reheating heat exchanger 210 cool simultaneously. The second switch 132 may be a four-way valve. Reheat throttle adjustment device 230 includes a reheat throttle valve and dehumidification throttle adjustment device 240 includes a dehumidification throttle valve. Also connected to the second switch 132 is an auxiliary branch pipe 170, and when the high-low pressure piping 160 communicates with the branch pipe 112, the auxiliary branch pipe 170 communicates with the suction pipe; when the high-low pressure pipe 160 communicates with the low-pressure suction pipe 113, the auxiliary branch pipe 170 communicates the low-pressure suction pipe 113 and the branch pipe 112. The auxiliary branch pipe 170 is provided with a filter 171 and a capillary tube 172.

Of course, in some embodiments, the first and

second switches

131 and 132 may exist at the same time, so that the air conditioner may be switched in three states of constant temperature dehumidification, single heating, and single cooling.

In order to better adjust the supercooling degree of the outdoor heat exchanger 141, the air conditioner further comprises an outdoor side throttling adjusting device 142, and the outdoor side throttling adjusting device 142 is positioned on the liquid side pipe 140 between the economizer 143 and the outdoor side heat exchanger 141. The outdoor side throttle adjusting means 142 comprises an outdoor throttle valve.

In some embodiments, in order to reduce the refrigerant pressure loss in the liquid side pipe 140, the air conditioner further includes a first check valve 134, and the first check valve 134 is connected in parallel with the outdoor side throttling adjustment device 142. The conducting direction of the first check valve 134 may be set according to different working conditions, and may be set to be one-way conducted from the outdoor heat exchanger 141 to the first intersection 211, or may be set to be one-way conducted from the first intersection 211 to the outdoor heat exchanger 141, taking the former as an example. When throttling is not necessary, the valve is opened as much as possible by the check valve 134, and when throttling is necessary, the outdoor throttle control device 142 is opened. The outdoor side throttle adjusting means 142 may be an electromagnetic throttle valve. In some embodiments, when the outdoor side throttling regulation device is a large-caliber throttling valve, the first check valve is not arranged; when the outdoor side throttling adjusting device is a throttling valve with a small diameter, the first one-way valve is arranged as much as possible to relieve the pressure in the throttling device, so that the throttling device is protected.

In some embodiments, to improve the ability of the air conditioner to heat at low temperatures, the air conditioner further comprises an economizer 143; the economizer 143 is provided in the liquid-side pipe 140 between the outdoor heat exchanger 141 and the first junction 211, and a return pipe 146 of the economizer 143 communicates with the medium-pressure suction port of the compressor 110. The return pipe 146 may have various forms, and the return pipe 146 may include only a return pipe body, or may include a return pipe body and a first communication pipe 148, and one end of the first communication pipe 148 is communicated with the return pipe body, and the other end is communicated with the medium-pressure suction port of the compressor 110.

A first control valve 133 is provided on the return line 146 or on a first communication line 148 between the return line 146 and the medium pressure suction port of the compressor 110. The compressor 110 in this case is a vapor injection enthalpy compressor 110, and has a low pressure suction port and an intermediate pressure suction port.

The economizer 143 has a throttling function, a first refrigerant flow path 143a and a second refrigerant flow path 143b are arranged in the economizer 143, and both ends of the first refrigerant flow path 143a are respectively communicated with the liquid side pipes 140 at both ends of the economizer 143; one end of the second refrigerant passage 143b is connected to the liquid-side pipe 140 via a liquid-taking pipe 145, and the other end is connected to the medium-pressure suction port of the compressor 110 via a return pipe 146; a liquid extraction throttle 144 is provided in the liquid extraction pipe 145. One end of the first refrigerant fluid communicates with a refrigerant inlet of the economizer 143, and the other end communicates with a refrigerant outlet of the economizer 143. The liquid-taking pipe 145 has one end communicating with the liquid-side pipe 140 and the other end communicating with the second refrigerant passage 143b, and the return pipe 146 has one end communicating with the medium-pressure suction port of the compressor 110 and the other end communicating with the second refrigerant passage 143 b.

In this way, the discharge air of the compressor 110 is switched by the first switch 131 and the second switch 132, and then enters the reheat heat exchanger 210 and the dehumidification heat exchanger 220 for heating, and the liquid refrigerant coming out of the reheat heat exchanger 210 and the dehumidification heat exchanger 220 enters the economizer 143 and then is divided into two parts: the first part directly enters the outdoor heat exchanger 141 for evaporation and heat absorption after being throttled and reduced in pressure by the outdoor throttling adjusting device 142 (electronic expansion valve), the second part enters the economizer 143 for heat absorption and evaporation after being throttled and reduced in pressure by the liquid taking throttle valve 144 (electronic expansion valve), the evaporated medium-pressure saturated steam enters the medium-pressure air suction port of the compressor 110 through the return pipe 146, the first control valve 133 and the connecting pipe 148 and is compressed together with the refrigerant of the low-pressure air suction port of the compressor 110 after being mixed with the refrigerant, the problems of small refrigerant flow, low return air pressure, high compression ratio and the like in a low-temperature environment are solved, and the reliability of the low-temperature heat production and the system is improved. By the technology of the invention, when the outdoor environment temperature is low, the refrigerant suction amount of the compressor 110 in the low-temperature environment is increased through the system design of the enhanced vapor injection compressor 110 and the economizer 143, so that the low-temperature heating capacity is improved, the compression ratio in the low-temperature environment is reduced, and the reliability of the system can be improved.

In order to improve the liquid taking effect, the inflow end of the liquid taking pipe 145 is communicated with the liquid side pipe 140 between the economizer 143 and the outdoor heat exchanger 141, and in other embodiments, the inflow end of the liquid taking pipe 145 can also be communicated with the liquid side pipe 140 between the economizer 143 and the first intersection 211. That is, the refrigerant flows in from the refrigerant outflow end of the economizer 143, which is advantageous for improving the reliability of liquid extraction.

In other embodiments, in order to avoid the unpleasant noise generated when the refrigerant in the vapor-liquid two-phase state passes through the indoor throttling device, the air conditioner further includes a gas-liquid separator 120 and an economizer 143, wherein the gas-liquid separator 120 is disposed on the low-pressure suction pipe 113; the economizer 143 is provided in the liquid-side pipe 140 between the outdoor heat exchanger 141 and the first junction 211, and a return pipe 146 of the economizer 143 communicates with the gas-liquid separator 120. The return pipe 146 may have various forms, and the return pipe 146 may include only a return pipe body, or may include a return pipe body and a second communication pipe 147, where one end of the second communication pipe 147 is communicated with the return pipe body, and the other end is communicated with the gas-liquid separator 120.

For convenience of control, in some examples, the return pipe 146 is communicated with the gas-liquid separator 120 through the low pressure suction pipe 113, and the return pipe 146 or a second connection pipe 147 between the return pipe 146 and the low pressure suction pipe 113 is provided with a second control valve 149.

The invention further reduces the condensation temperature of the refrigerant at the outlet of the outdoor heat exchanger 141 by adopting the system design with the economizer 143 on the basis of the three-pipe dehumidification reheating scheme and controlling the liquid taking throttle valve 144 (electronic expansion valve) in the system design loop with the economizer 143, improves the supercooling degree, leads the refrigerant to be completely condensed into liquid state, leads the liquid refrigerant to enter the indoor heat exchanger for heat absorption and evaporation after being throttled and decompressed by the indoor electronic expansion valve, and can solve the abnormal sound of the refrigerant generated by the gas-liquid two-phase state when the refrigerant passing through the indoor throttling device is in the full liquid state.

After the discharge of the compressor 110 is switched by the first switch 131, the high-pressure and high-temperature gaseous refrigerant enters the outdoor heat exchanger 141 for condensation and heat exchange, and the gas-liquid two-phase medium-temperature and high-pressure refrigerant coming out of the outdoor heat exchanger 141 enters the economizer 143 and is divided into two parts: the first part is throttled and depressurized by the liquid taking throttle valve 144, then enters the economizer 143 through the liquid taking pipe 145 to absorb heat and evaporate, the evaporated gaseous refrigerant enters the air suction port of the compressor 110 through the return pipe 146, the second control valve 149 (solenoid valve) and the connecting pipe 147 enter the gas-liquid separator 120 and are mixed with the gaseous refrigerant after the heat absorption and evaporation by the indoor heat exchanger, the second part further condenses and exchanges heat from the economizer 143, the gas-liquid two-phase refrigerant is changed into a pure liquid refrigerant, the pure liquid refrigerant flows indoors, and the pure liquid refrigerant is throttled and depressurized by the dehumidification throttle valve and the reheating throttle valve and then enters the dehumidification heat exchanger 220 and the reheating heat exchanger 210 to absorb heat and evaporate. The refrigerant entering the dehumidification regulating valve and the reheating regulating valve (electronic expansion valve) is changed into pure liquid from gas-liquid two-phase state, so that the problem of refrigerant abnormal sound generated when the gas-liquid two-phase refrigerant passes through the throttling device is solved.

In this embodiment, according to the technical scheme of the present invention, the condensation temperature of the refrigerant at the outlet of the outdoor heat exchanger 141 can be further reduced, the supercooling degree is increased, the refrigerant is completely condensed from a gas-liquid two-phase state to a liquid state, the liquid refrigerant enters the indoor heat exchanger to absorb heat and evaporate after being throttled and depressurized by the indoor electronic expansion valve (the dehumidification throttle valve and the reheating throttle valve), and when the refrigerant passing through the indoor throttling device (the dehumidification throttle valve and the reheating throttle valve) is in a full liquid state, the problem of refrigerant abnormal sound generated by the gas-liquid two-phase refrigerant passing through the throttling device can be solved, and the satisfaction degree of a user is improved

It should be noted that in some embodiments, the return pipe 146 is connected to the intermediate-pressure suction port of the compressor 110 and the gas-liquid separator 120 through different connection pipes, and in this case, the first control valve 133 (close to the compressor 110) and the second control valve 149 (close to the gas-liquid separator 120) are respectively disposed on the two connection pipes (the first connection pipe and the second connection pipe). The return pipe comprises a return pipe body and two communicating pipes. In the heating mode, the second control valve 149 is closed, and the first control valve 133 is opened, so that the refrigerant flows into the compressor 110, thereby improving the heating capacity; in the cooling mode or the constant temperature dehumidification mode, the first control valve 133 is closed, and the second control valve 149 is opened to remove noise. Of course, in some embodiments, second control valve 149 may be closed and first control valve 133 may be opened as required by particular operating conditions. The arrangement is such that the air conditioner can adjust the first control valve 133 and the second control valve 149 according to specific conditions, thereby improving the heating capacity of the air conditioner in the heating mode and reducing noise in the cooling and constant temperature dehumidification modes.

Regarding the specific connection between the compressor 110 and the economizer 143, the compressor 110 is an enhanced vapor injection compressor 110, and the compressor 110 has a conventional high pressure discharge port P, a low pressure suction port S, and a medium pressure suction port M (i.e., a vapor injection port) through which medium pressure refrigerant vapor enters the compressor 110 to increase the effective flow rate of the refrigerant.

The port a of the economizer 143 is connected to one end of the outdoor heat exchanger 141, the port b of the economizer 143 is connected to the second cross point 212, the port c of the economizer 143 is connected to the liquid taking pipe 145, the port d of the economizer 143 is connected to the return pipe 146, the liquid taking throttle valve 144 is connected in series to the liquid taking pipe 145, the first control valve 133 is connected in series to a connection pipe, the second control valve 149 is connected in series to another connection pipe, one end of the connection pipe is connected to the medium pressure suction port M of the compressor 110, and the other connection pipe is connected to the inlet end of the gas-liquid separator 120.

In some embodiments, the air conditioner further includes a plurality of indoor units 200, and the heat exchanger types included in the respective indoor units 200 may be different, such as one or more of an indoor unit with a constant temperature dehumidification function (having both the dehumidification heat exchanger 220 and the reheating heat exchanger 210), an ordinary cooling/heating indoor unit (having only one heat exchanger 270 and the corresponding throttling device 280), and an indoor unit with a switching device capable of freely switching a cooling or heating state, so that the air conditioner can simultaneously perform a hybrid operation of constant temperature dehumidification, cooling, heating, and the like.

Specifically, the air conditioner further includes: a first connection pipe 260 branched from a second intersection 212 of the liquid side pipe 140, and a second connection pipe 250 branched from the gas side pipe 150, wherein the second intersection 212 is located between the dehumidification throttle control device 240 and the outdoor heat exchanger 141, and the air conditioner further includes a plurality of indoor units 200, and the plurality of indoor units 200 are connected in parallel to the first connection pipe 260 and the second connection pipe 250.

In some embodiments, to improve the reliability of the second switch 132, the second switch 132 does not use a four-way valve, but is controlled by two solenoid valves. Specifically, the high-low pressure pipe 160 communicates with the branch pipe 112 and with the low pressure suction pipe 113 or the gas side pipe 150, the branch pipe 112 is provided with a third control valve 310, the high-low pressure pipe 160 communicates with the low pressure suction pipe 113 or the gas side pipe through a communication pipe 114, and the communication pipe 114 is provided with a fourth control valve 320. Note that the end of the communication pipe 114 remote from the high-low pressure pipe 160 may communicate with the gas-side pipe 150 between the first switch 131 and the indoor heat exchanger, or may communicate with the gas-side pipe 150 between the first switch 131 and the gas-liquid separator. Since the third control valve 310 and the fourth control valve 320 are separate control valves, the structure is simpler, and the stability and reliability are higher compared to a four-way valve. In addition, the third and

fourth control valves

310 and 320 may be solenoid valves. The solenoid valve can still work stably and reliably under the condition that the liquid refrigerant enters, and if the liquid refrigerant enters the four-way valve, the working stability of the solenoid valve is affected, so that the stability and reliability of the operation and state switching of the air conditioner can be improved by using the independent third control valve 310 and the independent fourth control valve 320.

It should be noted that the third control valve 310 and the fourth control valve 320 may be set to the de-energized state according to actual operating condition requirements. Taking the third control valve 310 as an example, in the operation process of the air conditioner, the time for the third control valve 310 to maintain the normally open state is long, at this time, the third control valve 310 can be selected as a normally open valve, that is, in the power-off state, most of the work can be completed, and only when the state of the third control valve 310 needs to be switched, power needs to be supplied to the third control valve; similarly, if the third control valve 310 remains normally closed for a long time, it is selected as a normally closed valve. In this way, the power consumed by the second switch 132 (including the third control valve 310) during the operation of the air conditioner is reduced, thereby facilitating the rational utilization of the power.

In some embodiments, the high-low pressure pipe 160, the branch pipe 112, and the low-pressure suction pipe 113 are connected to the first connection Q in order to simplify the piping structure, and of course, the low-pressure suction pipe 113 may communicate with the other two pipes through the communication pipe 114. In this case, a three-way valve may be provided at the first connection Q instead of two-way valves. The three-way valve realizes that the high-low pressure piping 160 is respectively communicated with the communicating pipe 114 and the branch pipe 112, and can respectively control the on-off of the communicating pipe 114 and the branch pipe, so that the convenience of connecting the high-low pressure piping 160, the communicating pipe 114 and the branch pipe 112 is improved.

A refrigeration mode:

the high-temperature and high-pressure refrigerant is discharged from the exhaust pipe 111, passes through the first switch 131, the liquid-side pipe 140, the outdoor heat exchanger, and the economizer in this order, and then enters the evaporating heat exchanger and the dehumidifying heat exchanger, respectively, to be cooled. A portion of the effluent from the dehumidification heat exchanger passes through the gas-side piping 150 and the first switch 131 (which may not be present in some embodiments) and flows into the gas-liquid separator; the other part flows out of the evaporation heat exchanger, passes through a high-pressure and low-pressure piping 160, enters the communicating pipe 114, and enters the gas-liquid separator through the low-pressure suction pipe 113 when the communicating pipe 114 is communicated with the low-pressure suction pipe; when the communication pipe 114 communicates with the gas-side pipe 150, the refrigerant flows into the gas-side pipe 150 through the communication pipe 114, and flows into the gas-liquid separator through the gas-side pipe 150. During this process, the third control valve 310 is closed and the fourth control valve 320 is opened.

Heating mode:

a high-temperature and high-pressure refrigerant is discharged from the exhaust pipe 111, and a part of the refrigerant passes through the first switch 131 (which may not be provided in some embodiments) and the gas-side piping 150 in sequence, enters the dehumidifying heat exchanger for heating, flows out of the dehumidifying heat exchanger, and enters the liquid-side piping 140; the other part enters the reheat heat exchanger through the branch pipe 112 and the high-low pressure pipe 160 in this order to be heated, flows out of the reheat heat exchanger, enters the liquid side pipe 140, passes through the economizer, the outdoor heat exchanger, and the first switch 131, and flows into the gas-liquid separator. During this process, the third control valve 310 is opened and the fourth control valve 320 is closed.

Constant temperature dehumidification mode:

the high-temperature and high-pressure refrigerant is discharged from the discharge pipe 111, and a portion of the refrigerant passes through the first switch 131 (which may not be provided in some embodiments), the liquid-side pipe 140, the outdoor-side heat exchanger, and the economizer in this order, then enters the dehumidifying heat exchanger to be cooled, and then flows into the gas-liquid separator through the gas-side pipe 150 and the first switch 131. The other part of the refrigerant enters the reheat heat exchanger through the branch pipe 112 and the high-low pressure pipe 160 in order to perform heating, and then flows into the dehumidification heat exchanger to perform cooling. During this process, the third control valve 310 is opened and the fourth control valve 320 is closed.

In some embodiments, the air conditioner is also used to supply water to floor heating or to prepare domestic water for people.

When the air conditioner further comprises a floor heating module, the air conditioner further comprises a heat exchange water tank and a floor heating water flow pipe communicated with the heat exchange water tank; the heat exchange water tank is internally provided with a ground heating heat exchanger, a refrigerant inlet of the ground heating heat exchanger is communicated with a high-pressure and low-pressure distribution pipe, a refrigerant outlet of the ground heating heat exchanger is communicated with a liquid side distribution pipe, and a sixth control valve is arranged on a gas side distribution pipe.

Specifically, in this embodiment, ground heating water pipe can bury underground in the middle of ground or the wall, ground heating water pipe and heat exchange water tank intercommunication, and water among the heat exchange water tank can be at ground heating water pipe mesocycle for the temperature in the ground heating water pipe is equivalent with the temperature in the heat exchange water tank. When a high-temperature and high-pressure refrigerant passes through the floor heating heat exchanger, the floor heating heat exchanger exchanges heat with water in a heat exchange water tank to heat cold water in the water tank; when low-pressure refrigerant passes through the floor heating heat exchanger, the floor heating heat exchanger exchanges heat with water in the heat exchange water tank to cool the water in the heat exchange water tank. When the ground heating heat exchanger works, the sixth control valve can be selectively closed (the sixth control valve needs to be closed when ground heating is carried out in a high-efficiency heating mode), and at the moment, the outdoor unit mainly serves the ground heating heat exchanger so as to improve the heat exchange efficiency of the ground heating heat exchanger.

In some other embodiments, the air conditioner further comprises: a first connection pipe branched from a second intersection of the liquid-side pipe, and a second connection pipe branched from the gas-side pipe, the second intersection being located between the dehumidification throttling regulation device and the outdoor heat exchanger; the air conditioner further comprises a water treatment device, the water treatment device comprises a water heat exchanger and a water container, the water heat exchanger is used for heating or refrigerating water in the water container, and the water heat exchanger and the indoor unit are connected to the first connecting pipe and the second connecting pipe in parallel. The water heat exchanger heats or refrigerates water in the water container, of course, the water containers can be multiple, and the water heat exchangers can also be multiple and arranged in parallel, so that one water container can contain hot water, and the other water container can contain cold water, and the cold water and the hot water can be supplied simultaneously. When hot water is required to be produced, high-temperature refrigerants pass through the water heat exchanger, so that heat energy is transferred to water in the container; when the refrigeration water is needed, the low-temperature refrigerant passes through the water heat exchanger, so that the cold energy is transferred to the water in the container.

In different operation modes, in order to achieve better cooling, heating or constant temperature dehumidification effects, the dehumidification throttle valve, the reheating throttle valve, the liquid-taking throttle valve 144 and the outdoor throttle valve need to be adjusted differently. The following description is made in a cooling mode, a heating mode, and a constant temperature dehumidification mode, respectively.

The control method in the refrigeration mode comprises the following steps:

supercooling degree adjustment of the economizer 143 (by adjusting the opening degree of the liquid-taking throttle valve 144);

the control method of the air conditioner comprises the following steps:

s10, under the refrigeration mode, obtaining the liquid-taking supercooling degree of the economizer 143; the supercooling degree is obtained by subtracting the temperature of the outlet of the heat exchanger from the temperature of the middle part of the heat exchanger;

specifically, in this embodiment, the liquid-taking supercooling degree is the temperature of the middle portion of the economizer 143 minus the temperature of the refrigerant outlet of the economizer 143. The temperature of the middle of the economizer 143 and the temperature of the refrigerant outlet are respectively obtained, and then the temperature of the refrigerant outlet of the economizer 143 is subtracted from the temperature of the middle of the economizer 143. Wherein, the supercooling degree of the liquid is the difference between the temperature of the port a and the temperature of the port b of the economizer, namely the temperature value of Ta-Tb.

S20, comparing the supercooling degree of the liquid with the target supercooling degree of the liquid;

and comparing the calculated supercooling degree of the liquid taking target with the supercooling degree of the liquid taking target, wherein the supercooling degree of the liquid taking target is 5-8 ℃.

S31, if the liquid taking supercooling degree is larger than the liquid taking target supercooling degree, reducing the opening degree of the liquid taking throttle valve 144; the opening of the liquid-taking throttle valve 144 is gradually adjusted, and the liquid-taking supercooling degree and the liquid-taking target supercooling degree are calculated and compared each time of adjustment until the liquid-taking supercooling degree falls within the range of the liquid-taking target supercooling degree.

When the supercooling degree of the liquid is greater than the target supercooling degree of the liquid, it is indicated that the temperature difference between the middle of the economizer 143 and the refrigerant outlet is large, and the temperature difference needs to be reduced, and at this time, the opening degree of the liquid-taking throttle valve 144 needs to be reduced to adjust the heat exchange, so that the temperature difference between the middle of the economizer 143 and the refrigerant outlet is reduced. So that the supercooling degree of the liquid is in the range of the target supercooling degree of the liquid. At this time, the refrigerant flowing from the economizer 143 to the dehumidification throttle valve and the reheat throttle valve is guaranteed to be in a pure liquid state, and noise is completely eliminated.

S32, if the liquid taking supercooling degree is smaller than the liquid taking target supercooling degree, increasing the opening degree of the liquid taking throttle valve 144;

when the supercooling degree of the liquid is smaller than the target supercooling degree of the liquid, it is indicated that the temperature difference between the middle of the economizer 143 and the refrigerant outlet is small, the temperature difference needs to be increased, and at this time, the opening degree of the liquid-taking throttle valve 144 needs to be increased to adjust the heat exchange, so that the temperature difference between the middle of the economizer 143 and the refrigerant outlet is increased. So that the supercooling degree of the liquid is in the range of the target supercooling degree of the liquid. At this time, the refrigerant flowing from the economizer 143 to the dehumidification throttle valve and the reheat throttle valve is guaranteed to be in a pure liquid state, and noise is completely eliminated.

And S33, if the liquid taking supercooling degree is equal to the liquid taking target supercooling degree, keeping the opening degree of the liquid taking throttle valve 144.

When the supercooling degree of the liquid is in the target supercooling degree range, the temperature difference of the economizer 143 is proper, so that the refrigerant flowing from the economizer 143 to the dehumidification throttle valve and the reheating throttle valve is in a pure liquid state, and abnormal sound is eliminated thoroughly.

Refrigerant superheat adjustment of reheat heat exchanger 210, and dehumidification refrigerant superheat adjustment of dehumidification heat exchanger 220

The control method of the air conditioner further includes:

s100, dehumidifying the outdoor unit at constant temperature, and acquiring the refrigerating superheat degree of a refrigerant inflow port of the liquid side piping in the indoor unit refrigerating mode;

the cooling superheat is a difference between a temperature Tb at the middle of the reheat heat exchanger 210 and a temperature Tc at the refrigerant outlet port. The temperature Tb at the middle of the reheat heat exchanger 210 and the temperature Tc at the refrigerant outlet of the reheat heat exchanger 210 during cooling are respectively detected, and the difference between the two is calculated.

S200, comparing the refrigerating superheat degree with a refrigerating target superheat degree;

the target superheat degree of the refrigeration is 0 to 10 ℃, for example, 1 to 4 ℃. And comparing the refrigerating superheat degree obtained by calculation with a refrigerating target superheat degree.

S310, if the refrigerating superheat degree is smaller than the refrigerating target superheat degree, reducing the opening degree of the reheating throttling adjusting device 230;

when the refrigerating superheat degree is smaller than the refrigerating target superheat degree, it is indicated that the temperature difference between the middle of the reheating heat exchanger 210 and the refrigerant outlet is small, the temperature difference needs to be increased, and at the moment, the opening degree of the reheating throttle valve needs to be reduced to adjust heat exchange, so that the temperature difference between the middle of the reheating heat exchanger 210 and the refrigerant outlet is increased. So that the degree of superheat of the refrigeration falls within the range of the target degree of superheat of the refrigeration. At this time, the heat exchange efficiency of the reheat heat exchanger 210 can be ensured, so that the heat exchange efficiency of the refrigerant in the reheat heat exchanger 210 is ensured, the liquid refrigerant is sufficiently evaporated, and the heat exchange effect is improved. And gradually adjusting the opening degree of the reheating throttle valve, and calculating and comparing the refrigerating superheat degree and the refrigerating target superheat degree every time of adjustment until the refrigerating superheat degree falls into the range of the refrigerating target superheat degree.

In some examples, the step of decreasing the opening degree of reheat throttle adjusting device 230 if the degree of superheat of refrigeration is less than the target degree of superheat of refrigeration specifically comprises:

if the refrigerating superheat degree is less than the refrigerating target superheat degree;

acquiring the current opening degree of the reheating throttle adjusting device 230, and comparing the current opening degree with the target opening degree range;

in this embodiment, the opening range of the reheat throttle valve is limited by the structure of the reheat throttle valve, that is, the limit opening and the limit closing; the reheating throttle valve can only move within a preset target opening range due to special working condition requirements.

If the current opening degree is larger than the minimum value of the target opening degree range, the opening degree of the reheating throttle adjusting device 230 is reduced; that is, when the current opening degree of the reheat throttle valve has a further reduction space, the opening degree of the reheat throttle valve can be directly reduced.

If the current opening degree is less than or equal to the minimum value of the target opening degree range, the opening degree of the liquid-taking throttle valve 144 is adjusted to increase the refrigeration superheat degree. That is, when the current opening degree of the reheat throttle valve does not have a further reduced space, the current opening degree of the reheat throttle valve is maintained (even the opening degree needs to be increased under some special working conditions to make the opening degree of the reheat throttle valve return to the target opening degree range), and the temperature and the pressure of the refrigerant in the refrigerant pipe are adjusted by adjusting the opening degree of the liquid-taking throttle valve 144, so as to finally achieve the purpose of adjusting the refrigeration superheat degree of the reheat heat exchanger 210, thereby ensuring the heat exchange effect.

The opening degree of the reheating throttling adjusting device can be adjusted according to the difference value between the refrigerating superheat degree and the refrigerating target superheat degree, and the larger the difference value between the refrigerating superheat degree and the refrigerating target superheat degree is, the more the number of steps of reducing the reheating throttling adjusting device each time is; the smaller the difference value of the refrigerating superheat degree smaller than the refrigerating target superheat degree is, the smaller the number of steps of reducing the reheating throttling adjusting device each time is.

Similarly, the more the difference value of the refrigerating superheat degree greater than the refrigerating target superheat degree is, the more the number of steps of the reheating throttling adjusting device is increased each time; the smaller the difference between the refrigerating superheat degree and the refrigerating target superheat degree is, the smaller the number of steps of the reheating throttling adjusting device is increased each time.

S320, if the refrigerating superheat degree is larger than the refrigerating target superheat degree, increasing the opening degree of the reheating throttling adjusting device 230;

when the refrigerating superheat degree is larger than the refrigerating target superheat degree, the temperature difference between the middle of the reheating heat exchanger 210 and the refrigerant outlet is large, the temperature difference needs to be reduced, at the moment, the opening degree of the reheating throttle valve needs to be increased to adjust heat exchange, and therefore the temperature difference between the middle of the economizer 143 and the refrigerant outlet is reduced. So that the degree of superheat of the refrigeration falls within the range of the target degree of superheat of the refrigeration. At this time, the heat exchange efficiency of the reheat heat exchanger 210 can be ensured, so that the heat exchange efficiency of the refrigerant in the reheat heat exchanger 210 is ensured, the liquid refrigerant is sufficiently evaporated, and the heat exchange effect is improved.

In some embodiments, if the refrigeration superheat is less than the refrigeration target superheat;

if the current opening is smaller than the maximum value of the target opening range, the opening of the reheat throttle adjusting device 230 is increased. That is, when the current opening degree of the reheat throttle valve has a further room for increase, the opening degree of the reheat throttle valve can be directly increased.

If the current opening degree is larger than or equal to the maximum value of the target opening degree range, the opening degree of the liquid-taking throttle valve 144 is adjusted to reduce the refrigeration superheat degree.

That is, when the current opening degree of the reheat throttle valve does not have a space for further increase, the current opening degree of the reheat throttle valve is maintained (even the opening degree needs to be reduced under some special working conditions to make the opening degree of the reheat throttle valve return to the target opening degree range), and the temperature and the pressure of the refrigerant in the refrigerant pipe are adjusted by adjusting the opening degree of the liquid-taking throttle valve 144, so as to finally achieve the purpose of adjusting the refrigeration superheat degree of the reheat heat exchanger 210, thereby ensuring the heat exchange effect.

In some embodiments, in order to achieve the effect of eliminating the abnormal noise more quickly, if the supercooling degree of the liquid taking valve is greater than the target supercooling degree of the liquid taking valve, the step of reducing the opening degree of the liquid taking throttle valve includes:

if the liquid-taking supercooling degree is larger than the liquid-taking target supercooling degree;

obtaining a fourth temperature difference value between the supercooling degree of the liquid taking and the target supercooling degree of the liquid taking;

and reducing the step number of the opening of the liquid taking throttle valve according to the fourth temperature difference value.

That is, different fourth temperature difference values will have different adjustment ranges, and the larger the fourth temperature difference value is, the more the number of steps of a single adjustment is, and the smaller the fourth temperature difference value is, the fewer the number of steps of a single adjustment is.

Specifically, the specific step of reducing the number of steps of the opening degree of the liquid taking throttle valve according to the fourth temperature difference value includes:

comparing the fourth temperature difference value with a fourth preset temperature difference value;

if the fourth temperature difference value is larger than a fourth preset temperature difference value, the speed of the liquid taking throttle valve is reduced to be step E/the adjusting time length;

if the fourth temperature difference value is smaller than a fourth preset temperature difference value, comparing the fourth temperature difference value with a fifth preset temperature difference value;

if the fourth temperature difference is greater than a fifth preset temperature difference and less than or equal to the fourth preset temperature difference, reducing the speed of the liquid taking throttle valve by F steps/adjusting the time length; wherein the value of E is greater than F;

and if the fourth temperature difference value is smaller than or equal to a fifth preset temperature difference value and larger than zero, keeping the opening of the liquid-taking throttle valve.

Note that the value of E, F may be a specific number of steps or a range of numbers of steps, and will be described below by way of example. And Tp is the fourth temperature difference (Ta-Tb) -T liquid taking target supercooling degree.

Tp is more than 3, the opening degree of an electronic expansion valve 144 in the economizer loop is reduced by 4 steps/every 120 seconds, wherein the value of E is 4, in some examples, the value of E can also be 3-5, and the fourth preset temperature difference value is 3 ℃; it should be noted that in this embodiment, the period of the adjustment of the liquid-taking throttle valve is 120 seconds.

Tp is more than 2 and less than or equal to 3, and the opening degree of the electronic expansion valve 144 in the economizer circuit is reduced by 2 steps/every 120 seconds. Wherein, the value of F is 2, and certainly in some examples, the value can also be 1-3, and the fifth preset temperature difference value is 2 ℃.

Tp is more than 0 and less than or equal to 2, and the opening degree of the electronic expansion valve 144 in the economizer circuit is maintained. And the supercooling degree of the liquid taking is greater than the target supercooling degree of the liquid taking, so that the fourth temperature difference value is greater than zero.

Similarly, if the liquid-taking supercooling degree is smaller than the liquid-taking target supercooling degree, the fifth temperature difference value at this time is smaller than zero, and the calculation logics are very similar.

If the liquid taking supercooling degree is smaller than the liquid taking target supercooling degree, the specific step of increasing the opening of the liquid taking throttle valve comprises the following steps:

if the liquid-taking supercooling degree is smaller than the liquid-taking target supercooling degree;

acquiring a fifth temperature difference value between the supercooling degree of the liquid taking and the target supercooling degree of the liquid taking;

and increasing the step number of the opening of the liquid taking throttle valve according to the fifth temperature difference value.

That is, different fifth temperature difference values will have different adjustment ranges, the smaller the fifth temperature difference value is, the more the number of steps of a single adjustment is, the larger the fifth temperature difference value is, the fewer the number of steps of a single adjustment is.

Specifically, the specific step of increasing the number of steps of the opening degree of the liquid taking throttle valve according to the fifth temperature difference value includes:

comparing the fifth temperature difference value with a sixth preset temperature difference value;

if the fifth temperature difference value is smaller than or equal to a sixth preset temperature difference value, the increasing rate of the liquid taking throttle valve is G steps/adjusting time length;

if the fifth temperature difference value is larger than a sixth preset temperature difference value, the increasing rate of the liquid taking throttle valve is H steps/adjusting time length; wherein the value of G is greater than H.

Note that the value of G, H may be a specific number of steps or a range of numbers of steps, and will be described below by way of example. Tq is the fifth temperature difference (Ta-Tb) -T liquid taking target supercooling degree.

Tq is less than or equal to minus 2, the opening degree of an electronic expansion valve 144 in the economizer circuit is increased by 4 steps/every 120 seconds, wherein the value of G is 4, in some examples, the value of G can also be 3-5, and the sixth preset temperature difference value is minus 2 ℃; it should be noted that in this embodiment, the period of the adjustment of the liquid-taking throttle valve is 120 seconds.

Tq is more than-2 and less than or equal to 0, and the opening degree of the electronic expansion valve 144 in the economizer circuit is increased by 2 steps/every 120 seconds. Wherein the value of H is 2, and certainly in some examples, the value of H can also be 1-3.

And S330, if the refrigerating superheat degree is equal to the refrigerating target superheat degree, keeping the opening degree of the reheating throttling adjusting device 230.

When the refrigerating superheat degree is within the refrigerating target superheat degree range, the temperature difference of the reheating heat exchanger 210 is appropriate, and the evaporation efficiency of the reheating heat exchanger 210 can be effectively ensured so as to ensure the heat exchange effect of the reheating heat exchanger 210.

When the outdoor unit is in a cooling state and the indoor unit is also in a cooling state:

the control method of the air conditioner further includes:

acquiring the refrigeration superheat degree of a refrigerant outflow port of a reheat heat exchanger;

comparing the refrigerating superheat degree with a refrigerating target superheat degree;

if the refrigerating superheat degree is smaller than the refrigerating target superheat degree, reducing the opening degree of a reheating throttling adjusting device;

if the refrigerating superheat degree is larger than the refrigerating target superheat degree, increasing the opening degree of a reheating throttling adjusting device;

and if the refrigerating superheat degree is equal to the refrigerating target superheat degree, keeping the opening degree of the reheating throttling adjusting device.

The opening degree of the reheating adjusting device can be adjusted according to the difference value between the refrigerating superheat degree and the refrigerating target superheat degree, and the larger the difference value between the refrigerating superheat degree and the refrigerating target superheat degree is, the more the number of steps of reducing the reheating throttling adjusting device each time is, or the faster the adjusting speed is; the smaller the difference between the refrigerating superheat degree and the refrigerating target superheat degree is, the smaller the number of steps of reducing the reheating throttling adjusting device each time is, or the slower the adjusting speed is.

Similarly, the more the difference value of the refrigerating superheat degree greater than the refrigerating target superheat degree is, the more the number of steps of the small reheat throttling adjusting device is increased each time, or the faster the adjusting speed is; the smaller the difference between the refrigerating superheat degree and the refrigerating target superheat degree is, the smaller the number of steps of the reheat throttling adjusting device is increased each time, or the slower the adjusting speed is. The refrigeration superheat degree is represented by Tu, when Tu is higher than 2 ℃, the opening degree of the indoor electronic expansion valve is increased, when Tu is lower than 2 ℃, the opening degree of the indoor electronic expansion valve is reduced, and when Tu is equal to 2 ℃, the opening degree is kept unchanged; the temperature of 2 ℃ in this case is an example, and may be in a range of 1.2 to 2.2 ℃.

Tu is more than 6 ℃, and the opening rate of the indoor electronic expansion valve is 10 steps/30 seconds;

tu is more than 4 and less than or equal to 6 ℃, and the opening rate of the indoor electronic expansion valve is 6 steps per 60 seconds;

tu is more than 3 and less than or equal to 4 ℃, and the opening rate of the indoor electronic expansion valve is 4 steps per 60 seconds;

tu is more than 2 and less than or equal to 3 ℃, and the opening rate of the indoor electronic expansion valve is 2 steps per 120 seconds;

keeping the opening degree of the indoor electronic expansion valve unchanged when Tu is 2 ℃;

tu is more than or equal to 1 and less than 2 ℃, and the opening closing rate of the indoor electronic expansion valve is 2 steps per 120 seconds;

tu is more than or equal to 0 and less than 1 ℃, and the opening closing rate of the indoor electronic expansion valve is 4 steps per 60 seconds;

tu is less than 0 ℃, and the opening degree of the indoor electronic expansion valve is closed at a rate of 8 steps per 30 seconds.

In the cooling mode, regarding the supercooling degree of the dehumidification heat exchanger 220, since the dehumidification heat exchanger 220 and the reheat heat exchanger 210 cool at the same time in the cooling mode, the supercooling degree of the dehumidification heat exchanger 220 and the reheat heat exchanger 210 are adjusted in the same manner, which will be briefly described below.

The control method of the air conditioner further includes:

acquiring the superheat degree of dehumidification refrigeration of a refrigerant outflow port of the dehumidification heat exchanger 220;

the superheat degree of dehumidification and refrigeration is the temperature of the refrigerant at the middle of the dehumidification heat exchanger 220 minus the temperature of the refrigerant at the refrigerant outlet of the dehumidification heat exchanger 220.

if the superheat degree of dehumidification refrigeration is smaller than the target superheat degree of dehumidification refrigeration, reducing the opening degree of the dehumidification throttling adjusting device 240;

if the dehumidification refrigeration superheat degree is larger than the dehumidification refrigeration target superheat degree, the opening degree of the dehumidification throttling adjusting device 240 is increased;

and if the superheat degree of dehumidification refrigeration is equal to the target superheat degree of dehumidification refrigeration, maintaining the opening degree of the dehumidification throttling adjusting device 240.

Similarly, if the opening degree of the dehumidification throttle valve reaches a limit value, the temperature and the pressure of the refrigerant in the pipeline can be adjusted by adjusting the opening degree of the liquid taking valve, so that the purpose of adjusting the superheat degree of dehumidification refrigeration is achieved, and the heat exchange effect of the dehumidification heat exchanger 220 is ensured.

In the cooling mode, the opening degree of the liquid intake throttle valve 144, the dehumidification throttle valve, and the reheat throttle valve is adjusted at the same time as possible so that the three valves can be adjusted as quickly as possible. It should be noted that, in the cooling mode, the heating mode and the constant temperature dehumidification mode, if the adjustment of the liquid intake throttle valve 144, the dehumidification throttle valve and the reheat throttle valve interferes with each other, the simultaneous adjustment of the three is avoided as much as possible.

The method further comprises the following steps before the step of obtaining the refrigerating superheat degree of the refrigerant inflow end of the reheat heat exchanger 210:

detecting the opening degree adjustment condition of the dehumidification throttling adjusting device 240;

if the dehumidification throttling regulation device 240 is adjusting the opening degree, the refrigeration superheat degree of the refrigerant outflow end of the reheat heat exchanger 210 is not obtained;

if the opening degree of the dehumidification throttling regulation device 240 is not adjusted, the refrigeration superheat degree of the refrigerant outflow end of the reheat heat exchanger 210 is obtained.

That is, before adjusting the opening of the reheat throttle valve, it is checked whether the dehumidification throttle valve is performing the opening adjustment, if so, the mutual interference between the dehumidification throttle valve and the reheat throttle valve is avoided, and after the opening adjustment of the dehumidification throttle valve is completed, the opening of the reheat throttle valve is adjusted. In order to avoid simultaneous adjustment of the dehumidification throttle valve and the reheat throttle valve as much as possible, the cycle duration of the dehumidification throttle valve and the reheat throttle valve can be set to be the same, but the adjustment time of the dehumidification throttle valve and the reheat throttle valve is set to be different, and the opening degrees of the dehumidification throttle valve and the reheat throttle valve are alternately adjusted. For example, the cycle duration is 20 seconds, in a certain period, the dehumidification throttle valve is adjusted after the first 20 seconds, the reheating throttle valve is adjusted after the second 20 seconds, and the dehumidification throttle valve is adjusted after the third 20 seconds, so that the dehumidification throttle valve and the reheating throttle valve are adjusted at different times.

Similarly, the opening degree adjustment state of the intake throttle valve 144 or the outdoor-side throttle adjusting device needs to be detected before the opening degree of the reheat throttle valve is adjusted, and if the opening degree adjustment state is being adjusted, the adjustment needs to be performed again after the adjustment is completed.

The method also comprises the following steps before the step of obtaining the liquid taking supercooling degree of the liquid taking throttle valve 144:

detecting the opening degree adjustment of the reheat throttle adjusting device 230;

if the opening degree of the reheat throttle adjusting device 230 is being adjusted, the liquid-taking supercooling degree of the liquid-taking throttle valve 144 is not obtained;

if the opening degree of the reheat throttle adjusting device 230 is not adjusted, the degree of supercooling of the intake liquid throttle valve 144 is acquired.

That is, before the opening degree of the intake throttle valve 144 is adjusted, it is checked whether or not the opening degree of the reheat throttle valve (dehumidification throttle valve) is being adjusted, and if the opening degree is being adjusted, the opening degree of the intake throttle valve 144 is adjusted after the opening degree adjustment of the reheat throttle valve (dehumidification throttle valve) is completed. In order to adjust the opening degree, the adjustment can be performed directly.

In order to prevent the liquid intake throttle valve 144 and the reheat throttle valve (dehumidification throttle valve) from opening simultaneously as much as possible, the adjustment cycle of the reheat throttle adjusting device 230 is shorter than the adjustment cycle of the liquid intake throttle valve 144. For example, the adjustment cycle of the reheat throttle valve is 20 seconds, and the adjustment cycle of the liquid intake throttle valve 144 is 2 minutes, so that the heat exchange effect of the reheat heat exchanger 210 (the dehumidification heat exchanger 220) can be sufficiently ensured (the cycle is short, the adjustment is fast, and the operation is accurate), and the generation of abnormal noise can be reduced as much as possible.

The control method in the heating mode comprises the following steps:

adjusting the superheat degree of the liquid-taking throttle valve 144;

the control method of the air conditioner comprises the following steps:

s1, acquiring the air supplement superheat degree of the economizer 143 in a heating mode;

the exhaust superheat is equal to the exhaust temperature minus the exhaust pressure saturation temperature. The suction superheat is equal to the suction temperature minus the saturation temperature corresponding to the suction pressure. Wherein, the degree of superheat of the air supply refers to the difference between the temperature of the port d of the economizer and the temperature of the port c of the economizer, namely Td-Tc. This heating mode is a heating mode of the indoor unit, and the outdoor unit may be a heating mode.

S2, comparing the air supply superheat degree with an air supply target superheat degree;

the gas supply target superheat degree is 1-3 ℃, and 2 ℃ is taken as an example.

S3-1, if the air supply superheat degree is larger than the air supply target superheat degree, increasing the opening degree of the liquid taking throttle valve 144; and gradually adjusting the opening of the liquid-taking throttle valve 144, and calculating and comparing the air-supply superheat degree and the air-supply target superheat degree every time of adjustment until the air-supply superheat degree falls into the range of the air-supply target superheat degree.

When the air supply superheat degree is larger than the air supply target superheat degree, the temperature difference between the air suction or exhaust temperature and the saturation temperature is large, the temperature difference needs to be reduced, at the moment, the opening degree of the liquid taking throttle valve 144 needs to be increased to adjust heat exchange, and therefore the temperature difference between the air suction or exhaust temperature and the saturation temperature of the economizer 143 is reduced. So that the gas supplementing superheat degree is within the range of the gas supplementing target superheat degree. At this time, the refrigerant throttled and depressurized by the liquid-taking throttle valve 144 (electronic expansion valve) enters the economizer 143 through the liquid-taking pipe 145 to absorb heat and evaporate, and the evaporated medium-pressure saturated vapor enters the medium-pressure suction port of the compressor 110 through the return pipe 146 and is mixed with the refrigerant at the low-pressure suction port of the compressor 110 to be compressed together, so that the problems of small refrigerant flow, low return pressure, high compression ratio and the like in a low-temperature environment are solved, and the low-temperature heating capacity and the reliability of the system are improved.

In some embodiments, the range of the opening of the liquid-taking throttle valve 144 may be defined by the structure of the liquid-taking throttle valve 144 itself, that is, the limit opening and the limit closing; or the liquid-taking throttle valve 144 can only move within the preset target opening range due to special working condition requirements.

If the air supply superheat degree is larger than the air supply target superheat degree, the specific step of increasing the opening degree of the liquid-taking throttle valve 144 comprises the following steps:

if the air supply superheat degree is larger than the air supply target superheat degree;

acquiring the current opening of the liquid-taking throttle valve 144, and comparing the current opening with the target opening range;

if the current opening is smaller than the maximum value of the target opening range, the opening of the liquid-taking throttle valve 144 is increased.

That is, when the current opening degree of the fetch throttle valve 144 has room for further increase, the opening degree of the fetch throttle valve 144 may be directly increased.

If the current opening is larger than or equal to the maximum value of the target opening range, the opening of the outdoor side throttling regulation device 142 is regulated until the air supply superheat degree is smaller than or equal to the air supply target superheat degree. That is, if the current opening of the liquid-extracting throttle valve 144 does not have a further increased space, the current opening of the liquid-extracting throttle valve 144 is maintained (even the opening needs to be reduced under some special conditions to make the opening of the liquid-extracting throttle valve 144 return to the target opening range), and the temperature and pressure of the refrigerant in the refrigerant pipe are adjusted by adjusting the opening of the outdoor-side throttle adjusting device 142, so as to finally achieve the purpose of adjusting the gas-supplementing superheat degree of the economizer 143, and to ensure the effect of the enthalpy-increasing compressor 110 on the injection enthalpy-increasing for heating.

In some embodiments, in order to achieve the enhanced vapor injection effect more quickly, the specific step of increasing the opening degree of the liquid-taking throttle valve if the gas-injection superheat degree is greater than the gas-injection target superheat degree comprises:

if the air supply superheat degree is larger than the target air supply superheat degree;

acquiring a first temperature difference value between the air supply superheat degree and the air supply target superheat degree;

and increasing the step number of the opening of the liquid taking throttle valve according to the first temperature difference.

That is, different first temperature difference values will have different adjustment ranges, the larger the first temperature difference value is, the more the number of steps of a single adjustment is, and the smaller the first temperature difference value is, the fewer the number of steps of a single adjustment is.

Specifically, the specific step of increasing the number of steps of the opening degree of the liquid taking throttle valve according to the first temperature difference value includes:

comparing the first temperature difference value with a first preset temperature difference value;

if the first temperature difference value is larger than a first preset temperature difference value, the increasing rate of the liquid taking throttle valve is step A/the adjusting time length;

if the first temperature difference value is smaller than a first preset temperature difference value, comparing the first temperature difference value with a second preset temperature difference value;

if the first temperature difference value is larger than the second preset temperature difference value and smaller than or equal to the first preset temperature difference value, the increasing rate of the liquid taking throttle valve is B step/adjusting time length; wherein the value of A is greater than B;

and if the first temperature difference value is smaller than or equal to a second preset temperature difference value and larger than zero, maintaining the opening of the liquid-taking throttle valve.

Note that the value of A, B may be a specific number of steps or a range of numbers of steps, and will be described below by way of example. Tm is the first temperature difference (Td-Tc) -T target degree of superheat for gas supply.

Tm is more than 3, the opening degree of an electronic expansion valve 144 in the economizer circuit is increased by 4 steps/every 120 seconds, wherein the value of A is 4, in some examples, the value of A can also be 3-5, and the first preset temperature difference value is 3 ℃; it should be noted that in this embodiment, the period of the adjustment of the liquid-taking throttle valve is 120 seconds.

Tm is more than 2 and less than or equal to 3, and the opening degree of the electronic expansion valve 144 in the economizer circuit is increased by 2 steps/every 120 seconds. Wherein the value of B is 2, and certainly in some examples, the value can also be 1-3, and the second preset temperature difference value is 2 ℃.

Tm is more than 0 and less than or equal to 2, and the opening degree of the electronic expansion valve 144 in the economizer loop is kept. The first temperature difference is greater than zero because the air supply superheat is greater than the air supply target superheat.

Similarly, if the gas supply superheat degree is less than the gas supply target superheat degree, the second temperature difference value is less than zero, and the calculation logic is very similar.

If the air supply superheat degree is smaller than the air supply target superheat degree, the specific step of reducing the opening degree of the liquid-taking throttle valve comprises the following steps:

if the air supply superheat degree is less than the air supply target superheat degree;

acquiring a second temperature difference value between the air supply superheat degree and the air supply target superheat degree;

and reducing the step number of the opening of the liquid taking throttle valve according to the second temperature difference value.

That is, different second temperature difference values will have different adjustment ranges, and the smaller the second temperature difference value is, the more the number of steps of a single adjustment is, the larger the second temperature difference value is, the fewer the number of steps of a single adjustment is.

Specifically, the specific step of reducing the number of steps of the opening degree of the liquid taking throttle valve according to the second temperature difference value includes:

comparing the second temperature difference value with a third preset temperature difference value;

if the second temperature difference is smaller than or equal to a third preset temperature difference, the reducing speed of the liquid taking throttle valve is C step/adjusting time length;

if the second temperature difference value is larger than a third preset temperature difference value, the reducing speed of the liquid taking throttle valve is D steps/adjusting time length; wherein the value of C is greater than D.

Note that the value of C, D may be a specific number of steps or a range of numbers of steps, and will be described below by way of example. Tn is the second temperature difference (Td-Tc) -T target degree of superheat for the gas supply.

Tn is less than or equal to minus 2, the opening degree of an electronic expansion valve 144 in the economizer circuit is reduced by 4 steps/every 120 seconds, wherein the value of C is 4, in some examples, the value of C can also be 3-5, and the third preset temperature difference value is minus 2 ℃; it should be noted that in this embodiment, the period of the adjustment of the liquid-taking throttle valve is 120 seconds.

Tn is more than-2 and less than or equal to 0, and the opening of the electronic expansion valve 144 in the economizer circuit is decreased by 2 steps/every 120 seconds. Wherein, the value of D is 2, and certainly in some examples, the value can also be 1-3.

In the heating mode, before the step of obtaining the air-supply superheat degree of the economizer, the method further comprises the following steps:

acquiring an outdoor environment temperature T4;

comparing the outdoor environment temperature T4 with the preset environment temperature T4-ph;

if the outdoor environment temperature is greater than or equal to the preset environment temperature, closing the liquid taking throttle valve;

and if the outdoor environment temperature is lower than the preset environment temperature, acquiring the air supplement superheat degree of the economizer.

Specifically, in this embodiment, the preset ambient temperature T4-ph may be 0 to 7 ℃, for example, 5 ℃ and 7 ℃, and when the current outdoor ambient temperature is higher than the preset ambient temperature, it indicates that the temporary ambient temperature does not require enhanced vapor injection to improve the heating performance, and at this time, the liquid-taking throttle valve may be closed. When present outdoor ambient temperature is less than preset ambient temperature, explain that need the compressor to increase enthalpy at present, just can make it improve the ability of heating under microthermal environment, at this moment, should open and get liquid choke valve to adjust it.

S3-2, if the air supply superheat degree is smaller than the air supply target superheat degree, reducing the opening degree of the liquid taking throttle valve 144;

when the gas supplementing superheat degree is smaller than the gas supplementing target superheat degree, the temperature difference between the gas suction or exhaust temperature and the saturation temperature is small, the temperature difference needs to be increased, at the moment, the opening degree of the liquid taking throttle valve 144 needs to be reduced to adjust heat exchange, and therefore the temperature difference between the gas suction or exhaust temperature and the saturation temperature of the economizer 143 is increased. So that the gas supplementing superheat degree is within the range of the gas supplementing target superheat degree. At this time, the refrigerant throttled and depressurized by the liquid-taking throttle valve 144 (electronic expansion valve) enters the economizer 143 through the liquid-taking pipe 145 to absorb heat and evaporate, and the evaporated medium-pressure saturated vapor enters the medium-pressure suction port of the compressor 110 through the return pipe 146 and is mixed with the refrigerant at the low-pressure suction port of the compressor 110 to be compressed together, so that the problems of small refrigerant flow, low return pressure, high compression ratio and the like in a low-temperature environment are solved, and the low-temperature heating capacity and the reliability of the system are improved.

In some embodiments, if the make-up air superheat is less than the make-up air target superheat, the step of decreasing the opening of pick-up throttle valve 144 comprises:

if the current opening is greater than the minimum value of the target opening range, the opening of the liquid-taking throttle valve 144 is decreased.

That is, when the current opening degree of the fetch throttle valve 144 has a further reduction space, the opening degree of the fetch throttle valve 144 can be directly reduced.

And if the current opening degree is smaller than or equal to the minimum value of the target opening degree range, reducing the opening degree of the outdoor side throttling device until the air supply superheat degree is larger than or equal to the air supply target superheat degree.

That is, if the current opening of the liquid-extracting throttle valve 144 does not have a further reduced space, the current opening of the liquid-extracting throttle valve 144 is maintained (even the opening needs to be increased under some special conditions to make the opening of the liquid-extracting throttle valve 144 return to the target opening range), and the temperature and pressure of the refrigerant in the refrigerant pipe are adjusted by adjusting the opening of the outdoor-side throttle adjusting device 142, so as to finally achieve the purpose of adjusting the gas-supplementing superheat degree of the economizer 143, and ensure the effect of the enthalpy-increasing compressor 110 on gas injection and heat production.

And S3-3, if the air supply superheat degree is equal to the air supply target superheat degree, keeping the opening degree of the liquid taking throttle valve 144. At this time, it is stated that the suction or discharge temperature is equivalent to the saturation temperature, and the economizer 143 at this time can better obtain the medium-pressure saturated steam, so as to effectively ensure the enthalpy increasing effect of the enthalpy increasing compressor 110 and improve the heating capacity of the air conditioner in the low-temperature environment.

Heating supercooling degree adjustment (timing) of reheat heat exchanger 210

In the heating mode, how to ensure the heating effect of the reheat heat exchanger 210 by adjusting the heating supercooling degree of the reheat heat exchanger 210 is described below, the air conditioner includes a plurality of indoor units, and the control method of the air conditioner further includes:

acquiring the middle temperature T2i of all the heating heat exchangers, and calculating the average value T2avg of the middle temperatures of the heating heat exchangers;

specifically, in the present embodiment, the middle temperature T2i of each heating heat exchanger may be T21, T22, T23 … … T2 n. The value of T2avg is the value of (T21+ T22+ T23+ … + T2 n)/n.

Calculating a third temperature difference value between T2i and T2avg at the middle part of the reheating heat exchanger in the heating mode;

assuming that the current middle temperature of the reheat heat exchanger is T28, the third temperature difference is the difference between T28 and T2 avg.

And adjusting the opening degree of the reheating throttle adjusting device according to the third temperature difference value.

Specifically, the third temperature difference is compared with a preset temperature range; if the third temperature difference value is within the current preset temperature range; and the reheating throttling device is adjusted according to the adjusting mode corresponding to the current preset temperature range. The preset temperature range is multiple, and each preset temperature range has a corresponding opening degree adjusting mode. And when the third temperature difference value falls into the corresponding preset temperature range, installing the adjusting mode corresponding to the current preset temperature range for adjusting.

In the heating mode, in order to avoid interference caused by simultaneous adjustment of the reheat throttle valve (dehumidification throttle valve) and the liquid intake throttle valve 144, the opening degree adjustment of the reheat throttle adjusting device 230 is detected; if the reheating throttle adjusting device 230 is adjusting the opening, the air supplement superheat degree of the liquid-taking throttle valve 144 is not obtained; if the opening degree of the reheat throttle adjusting device 230 is not adjusted, the degree of superheat of the make-up air of the liquid-taking throttle valve 144 is acquired. That is, before the opening degree of the reheat throttle valve is adjusted, it is detected whether the opening degree of the take-out throttle valve 144 is being adjusted, and if the opening degree of the take-out throttle valve 144 is being adjusted, the opening degree of the reheat throttle valve is adjusted after the opening degree adjustment of the take-out throttle valve is completed.

It should be noted that, in the heating mode, when only one indoor heat exchanger is located at the indoor side, the throttle valve is adjusted to a preset opening degree.

When a plurality of indoor heat exchangers are arranged at the indoor side, under the heating mode, the average value T2avg (target supercooling degree) of the temperatures of the middle parts of all the heating heat exchangers is calculated firstly, then the temperature T2i (heating supercooling degree) of the middle part of the indoor heat exchanger operated in the current heating mode is differed from the average value T2avg (target supercooling degree), a third temperature difference value To (To is T2i-T2avg) obtained by differencing is compared with the preset temperature, the preset temperature stage in which the third temperature difference value is located is judged, and different adjustment steps and adjustment modes are arranged in different temperature stages. Note that To may be within a certain range.

For example:

when the third temperature difference is less than the fourth preset temperature, the opening of the throttle valve is greatly opened, To is less than-3 ℃, and the opening of the electronic expansion valve is opened by 8 steps/every 120 seconds, namely the opening of the throttle valve is increased by eight steps every cycle;

-3 To 2 ℃, opening of the electronic expansion valve is increased by 4 steps/every 120 seconds, namely, the throttle valve is opened by four steps in each period;

and (3) To is more than or equal To-2 ℃ and less than or equal To 2 ℃, the opening of the electronic expansion valve is kept unchanged, namely the throttle valve is kept inconvenient To open, and at the moment, the heating supercooling degree is equivalent To the target heating supercooling degree.

The To is more than 2 and less than or equal To 3 ℃, the opening of the electronic expansion valve is reduced by 4 steps/every 120 seconds, namely, the throttle valve is reduced by four steps in each period;

to >3 deg.c and the electronic expansion valve opening is closed 8 steps/every 120 seconds, i.e. the throttle valve is reduced by eight steps per cycle.

In some embodiments, in order to avoid opening adjustment of the liquid taking throttle valve 144 and the reheat throttle valve at the same time as much as possible, the adjustment period of the reheat throttle adjusting device 230 and the dehumidification throttle adjusting device is shorter than the adjustment period of the liquid taking throttle valve 144. For example, the adjustment cycle of the reheat throttle valve is 20 seconds, and the adjustment cycle of the liquid-extraction throttle valve 144 is 2 minutes, so that the heating effect of the reheat heat exchanger 210 (the dehumidification heat exchanger 220) can be sufficiently ensured (the cycle is short, the adjustment is fast, and the operation is accurate), the enthalpy-increasing effect of the enthalpy-increasing compressor 110 can be ensured as much as possible, and the heating performance of the compressor 110 can be sufficiently improved.

The control method in the constant-temperature dehumidification mode comprises the following steps:

the control method of the air conditioner comprises the following steps:

s1000, obtaining the reheating supercooling degree of a refrigerant outflow end of a reheating heat exchanger 210 when the indoor unit and the outdoor unit are in a constant-temperature dehumidification mode;

the reheat supercooling degree is a difference between a temperature Tb at the middle of the reheat heat exchanger 210 and a temperature Ta at the outlet of the refrigerant. The temperature Tb at the middle of the reheat heat exchanger 210 and the temperature Ta at the refrigerant outlet of the reheat heat exchanger 210 during cooling are respectively detected, and the difference between the two is calculated.

S2000, comparing the reheating supercooling degree with the reheating target supercooling degree;

the target supercooling degree of reheating is 2 to 15 ℃, for example, 8 to 12 ℃. And comparing the refrigerating superheat degree obtained by calculation with a refrigerating target superheat degree.

S3100, if the reheating supercooling degree is smaller than the reheating target supercooling degree, reducing the opening degree of a reheating regulating valve;

when the reheating supercooling degree is smaller than the refrigerating target superheat degree, it is indicated that the temperature difference between the middle of the reheating heat exchanger 210 and the refrigerant outlet is small, the temperature difference needs to be increased, and at the moment, the opening degree of the reheating throttle valve needs to be reduced to adjust heat exchange, so that the temperature difference between the middle of the reheating heat exchanger 210 and the refrigerant outlet is increased. So that the reheat supercooling degree is within the range of the reheat target supercooling degree. In this case, the heating efficiency of the reheat heat exchanger 210 can be ensured, so that the heat exchange efficiency of the refrigerant in the reheat heat exchanger 210 can be ensured, and the heating effect can be improved. And gradually adjusting the opening of the reheating throttle valve, and calculating and comparing the reheating supercooling degree and the refrigerating target superheat degree every time of adjustment until the reheating supercooling degree falls into the range of the refrigerating target superheat degree.

In some embodiments, the specific step of decreasing the opening degree of reheat throttle adjusting device 230 if the reheat subcooling degree is smaller than the reheat target subcooling degree comprises:

If the current opening is greater than the minimum value of the target opening range, the opening of the reheat throttle adjusting device 230 is decreased. That is, when the current opening degree of the reheat throttle valve has a further reduction space, the opening degree of the reheat throttle valve can be directly reduced.

And if the current opening is smaller than or equal to the minimum value of the target opening range, adjusting the opening of the liquid-taking throttle valve 144 or the opening of the outdoor-side throttling adjusting device 142 to increase the reheating supercooling degree. That is, when the current opening of the reheat throttle valve does not have a further reduced space, the current opening of the reheat throttle valve is maintained (even the opening needs to be increased under some special conditions to make the opening of the reheat throttle valve return to the target opening range), and the temperature and pressure of the refrigerant in the refrigerant pipe are adjusted by adjusting the opening of the liquid-taking throttle valve 144 or the outdoor throttle adjusting device 142, so as to finally achieve the purpose of adjusting the reheat supercooling degree of the reheat heat exchanger 210, thereby ensuring the heating effect.

S3200, if the reheating supercooling degree is larger than the reheating target supercooling degree, increasing the opening degree of a reheating regulating valve;

when the reheating supercooling degree is greater than the reheating target supercooling degree, the difference between the temperature of the middle of the reheating heat exchanger 210 and the refrigerant outlet is large, the difference between the temperatures needs to be reduced, and at the moment, the opening of the reheating throttle valve needs to be increased to adjust heat exchange, so that the difference between the temperature of the middle of the reheating heat exchanger 210 and the refrigerant outlet is reduced. So that the reheat supercooling degree is within the range of the reheat target supercooling degree. In this case, the heating efficiency of the reheat heat exchanger 210 can be ensured, so that the heat exchange efficiency of the refrigerant in the reheat heat exchanger 210 can be ensured, and the heating effect can be improved.

In some embodiments, if the reheat subcooling is greater than the reheat target subcooling, the specific step of increasing the opening of reheat throttle adjustment device 230 includes:

If the current opening is larger than or equal to the maximum value of the target opening range, the opening of the liquid-taking throttle valve 144 or the outdoor-side throttling regulation device is regulated to reduce the reheating supercooling degree. That is, when the current opening of the reheat throttle valve does not have a further increased space, the current opening of the reheat throttle valve is maintained (even the opening needs to be reduced under some special conditions to make the opening of the reheat throttle valve return to the target opening range), and the temperature and pressure of the refrigerant in the refrigerant pipe are adjusted by adjusting the opening of the liquid-taking throttle valve 144 or the outdoor-side throttle adjusting device, so as to finally achieve the purpose of adjusting the reheat supercooling degree of the reheat heat exchanger 210, thereby ensuring the reheat effect.

And S3300, if the reheating supercooling degree is equal to the reheating target supercooling degree, keeping the opening degree of the reheating adjusting valve.

When the reheating supercooling degree is within the reheating target supercooling degree range, the temperature difference of the reheating heat exchanger 210 is proper, and the condensing efficiency of the reheating heat exchanger 210 can be effectively ensured so as to ensure the reheating effect of the reheating heat exchanger 210.

In the constant temperature dehumidification mode, the control method of the air conditioner further comprises:

It should be noted that the superheat degree of dehumidification cooling of the dehumidification heat exchanger 220 in the constant temperature dehumidification mode is different from the superheat degree of dehumidification cooling of the dehumidification heat exchanger 220 in the refrigeration mode, and in the constant temperature dehumidification mode, the superheat degree of dehumidification cooling is not only adjusted by the dehumidification throttle valve, but also affected by the liquid-taking throttle valve 144 and the reheat throttle valve. Therefore, it should be avoided as much as possible that the dehumidification throttle valve is adjusted simultaneously with the intake throttle valve 144 or the reheat throttle valve.

Avoid reheat throttle and dehumidification throttle to adjust simultaneously:

the method further comprises the following steps before the step of obtaining the reheating supercooling degree of the refrigerant outflow end of the reheating heat exchanger 210:

if the dehumidification throttling regulation device 240 is adjusting the opening degree, the reheating supercooling degree of the refrigerant outflow end of the reheating heat exchanger 210 is not obtained;

if the opening degree of the dehumidification throttling regulation device 240 is not adjusted, the reheat and supercooling degree of the refrigerant outflow end of the reheat heat exchanger 210 is obtained.

So for the air conditioner can be fast, reliable carry out the adjustment of dehumidification choke valve and reheat throttle valve opening degree, avoid interference each other, and the constant temperature dehumidification effect of air conditioner is guaranteed to effectual dehumidification effect and the reheat effect of reheat heat exchanger 210 of guaranteeing dehumidification heat exchanger 220.

Avoiding simultaneous adjustment of reheat and take-off throttle valves 144:

detecting the opening adjustment condition of the liquid-taking throttle valve 144;

if the opening of the liquid-taking throttle valve 144 is being adjusted, the reheating supercooling degree of the refrigerant outflow end of the reheating heat exchanger 210 is not obtained;

if the opening degree of the liquid-taking throttle valve 144 is not adjusted, the reheating supercooling degree of the refrigerant outflow end of the reheating heat exchanger 210 is obtained.

So for the adjustment of liquid choke valve 144 and reheat throttle valve aperture can be got fast, reliably to the air conditioner, avoids mutual interference, both can effectually guarantee the elimination to the abnormal sound, can guarantee reheat heat exchanger 210's reheat effect again.

A control method in which the indoor side is provided with a plurality of indoor units 200 will be described.

A control method of an air conditioner, comprising:

a: acquiring the required cold or heat of each heat exchanger of the indoor unit 200;

the air conditioner includes a plurality of indoor units 200, each indoor unit 200 includes a different number of heat exchangers, the heat exchangers can cool or heat, and the operating condition of each indoor heat exchanger is set according to the user's demand. Thus, the operating mode and the required energy of the heat exchanger on the indoor side can be different. The amount of cold or heat required depends on the operating parameters set by the user.

B: calculating the total cold requirement and the total heat requirement of the indoor unit 200 according to the cold or heat required by each heat exchanger;

adding the heat required by all the heating heat exchangers to obtain the total heat requirement; and adding the cold quantity required by all the refrigerated heat exchangers to obtain the total cold quantity requirement.

C: and adjusting the operation parameters of the compressor according to the total cold requirement and the total heat requirement.

Specifically, the step of adjusting the operating parameters of the compressor according to the total cooling demand and the total heating demand includes:

c1: comparing the total cold requirement with the total heat requirement; namely, the total cold requirement and the total heat requirement are compared, the comparison result has three types, the total cold requirement is greater than the total heat requirement, the total cold requirement is less than the total heat requirement, and the total cold requirement is equal to the total heat requirement.

C2: if the total cold requirement is greater than the total heat requirement, the compressor adjusts the running frequency of the compressor according to the evaporation temperature of the low-pressure suction inlet; the method specifically comprises the following steps:

if the total cold requirement is greater than the total heat requirement;

detecting a current operating state of the outdoor unit 100;

if the outdoor unit 100 is in the heating state, switching to the cooling state or the constant temperature dehumidification state; if the temperature is in a refrigeration state or a constant temperature dehumidification state, continuously keeping;

the compressor adjusts the operating frequency of the compressor according to the evaporating temperature of the low-pressure suction inlet.

In this embodiment, under the condition that the total demand of cold volume is greater than the total demand of heat, the compressor needs to provide cold volume for the indoor side, and the mode of providing cold volume has a refrigeration mode and a constant temperature dehumidification mode, so that the current operation mode needs to be confirmed at this moment. Firstly, detecting the operation state of the outdoor unit 100 of the current air conditioner, and if the outdoor unit 100 is in a heating state, switching to a cooling state or a constant temperature dehumidification state; if the temperature is in a refrigeration state or a constant temperature dehumidification state, the temperature is kept continuously. On this basis, the more the total cooling demand is greater than the total heating demand, the more cooling energy the outdoor unit 100 needs to provide; the larger the total cold requirement and the total heat requirement are, the higher the running frequency of the compressor is required; similarly, the less the total demand for cooling is greater than the total demand for heat, the less cooling energy the outdoor unit 100 needs to provide; the smaller the total cooling and heating requirements, the lower the frequency at which the compressor needs to be operated.

C3: and if the total cold requirement is less than the total heat requirement, the compressor adjusts the running frequency of the compressor according to the condensation temperature of the high-pressure exhaust port.

If the total cold requirement is less than the total heat requirement, the step of adjusting the operating frequency of the compressor by the compressor according to the condensation temperature of the high-pressure exhaust port specifically comprises the following steps:

if the total cold requirement is less than the total heat requirement;

detecting a current operating state of the outdoor unit 100;

if the outdoor unit 100 is in the cooling state or the constant temperature dehumidification state, switching to the heating state; if the heating state is the heating state, continuously keeping;

In this embodiment, under the condition that the total cooling demand is less than the total heat demand, the compressor needs to provide heat to the indoor side, and there is a heating mode as a mode for providing heat, so that the current operation mode needs to be confirmed at this time. Firstly, detecting the operation state of the outdoor unit 100 of the current air conditioner, and switching to a heating state if the outdoor unit 100 is in a refrigerating state or a constant-temperature dehumidification state; if the heating state is the heating state, the heating state is continuously maintained. On this basis, the more the total demand for heat is greater than the total demand for cold, the more heat energy the outdoor unit 100 needs to provide; the larger the total cold requirement and the total heat requirement are, the higher the running frequency of the compressor is required; similarly, the less the total demand for heat is greater than the total demand for cold, the less heat energy the outdoor unit 100 needs to provide; the smaller the total cooling and heating requirements, the lower the frequency at which the compressor needs to be operated.

In some embodiments, the exhaust pipe 111 is provided with a fifth control valve 330, and the step of adjusting the operation parameter of the compressor according to the total cooling demand and the total heating demand further comprises:

c4: if the total cold demand equals the total heat demand, the fifth control valve 330 is closed. If the total cooling demand is equal to the total heating demand, the outdoor unit 100 does not need to provide cooling energy and heating energy to the indoor side. Therefore, the refrigerant at this time may not pass through the outdoor heat exchanger. By closing the fifth control valve 330, the refrigerant flow is prevented from flowing back and the refrigerant is prevented from being excessively accumulated in the outdoor unit 100, thereby preventing the insufficient amount of the refrigerant circulating therethrough. In some embodiments, the third control valve 310 may also be closed.

In this embodiment, the required cooling capacity or heat capacity of each heat exchanger of the indoor unit 200 is obtained first; then, calculating the total cold requirement and the total heat requirement of the indoor unit 200 according to the cold quantity or the heat quantity required by each heat exchanger; then, adjusting the operation parameters of the compressor according to the total cold quantity demand and the total heat quantity demand; the heat exchanger at the indoor side is guided by the pressure difference to transfer and exchange energy so as to realize heat recovery or partial heat recovery; the method and the device can provide personalized service for the user and simultaneously fully improve the utilization rate of energy.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. The control method of the air conditioner is characterized by comprising an outdoor unit and an indoor unit, wherein the outdoor unit comprises a compression mechanism and an outdoor heat exchanger, and the indoor unit comprises a dehumidification heat exchanger and a dehumidification throttling regulation device;

the air conditioner also comprises a gas-liquid separator and an economizer, wherein the gas-liquid separator is arranged on the low-pressure suction pipe; the economizer is arranged on a liquid side pipe between the outdoor heat exchanger and the first intersection point, and a return pipe of the economizer is communicated with the gas-liquid separator;

the return pipe of the economizer is communicated with the medium-pressure suction inlet of the compressor;

the backflow pipe comprises a backflow pipe body, a first communicating pipe and a second communicating pipe;

one end of the first communicating pipe is communicated with the return pipe body, the other end of the first communicating pipe is communicated with the medium-pressure suction inlet of the compressor, and a first control valve is arranged on the first communicating pipe;

one end of the second communicating pipe is communicated with the return pipe body, the other end of the second communicating pipe is communicated with the gas-liquid separator, and a second control valve is arranged on the second communicating pipe;

the control method of the air conditioner comprises the following steps:

under a constant temperature dehumidification mode, obtaining the reheating supercooling degree of a refrigerant outflow end of a reheating heat exchanger;

if the reheating supercooling degree is equal to the reheating target supercooling degree, keeping the opening degree of the reheating regulating valve;

2. The control method of an air conditioner according to claim 1,

a first refrigerant flow path and a second refrigerant flow path are arranged in the economizer, and two ends of the first refrigerant flow path are respectively communicated with liquid side piping at two ends of the economizer; one end of the second refrigerant flow path is communicated with the liquid side pipe through a liquid taking pipe, and the other end of the second refrigerant flow path is communicated with a medium-pressure suction inlet of the compressor through a return pipe; a liquid taking throttle valve is arranged on the liquid taking pipe;

3. The control method of an air conditioner according to claim 2, further comprising, after the step of obtaining a current opening degree of the reheat throttle adjusting means, and comparing the current opening degree with a target opening degree range:

4. The method of controlling an air conditioner according to claim 2, wherein if the reheat subcooling degree is smaller than the reheat target subcooling degree, the concrete step of reducing the opening degree of the reheat throttle adjusting means includes:

5. The control method of an air conditioner according to claim 4, further comprising, after the step of obtaining a current opening degree of the reheat throttle adjusting means, and comparing the current opening degree with a target opening degree range:

6. The control method of an air conditioner according to claim 2, wherein the return pipe is communicated with the gas-liquid separator through a low pressure suction pipe, and the second control valve is provided on the return pipe or a connection pipe between the return pipe and the low pressure suction pipe.

7. The control method of an air conditioner according to claim 2, wherein an inflow end of the liquid take-out pipe communicates with a liquid side pipe between the economizer and the outdoor side heat exchanger; alternatively, the first and second electrodes may be,

8. The control method of an air conditioner according to claim 1,

the outdoor unit further comprises a first switch switchable between a first switch first switching state and a first switch second switching state,

9. The control method of an air conditioner according to claim 8,

the air conditioner further includes a second switch capable of switching between a third switching state and a fourth switching state of the second switch,

10. The method as claimed in claim 1, further comprising, before the step of obtaining the degree of subcooling of the refrigerant outflow end of the reheat heat exchanger, the steps of:

11. The method of controlling an air conditioner according to claim 1, wherein the opening degree of the dehumidification throttle control means and the opening degree of the reheat throttle control means are alternately adjusted.

12. The control method of an air conditioner according to claim 1,

the air conditioner also comprises a gas-liquid separator and an economizer, wherein the gas-liquid separator is arranged on the low-pressure suction pipe; the economizer is arranged on a liquid side pipe between the outdoor heat exchanger and the first intersection point, and a return pipe of the economizer is communicated with the gas-liquid separator; the economizer is internally provided with a first refrigerant flow path and a second refrigerant flow path, and two ends of the first refrigerant flow path are respectively communicated with liquid side distribution pipes at two ends of the economizer; one end of the second refrigerant flow path is communicated with the liquid side pipe through a liquid taking pipe, and the other end of the second refrigerant flow path is communicated with a medium-pressure suction inlet of the compressor through a return pipe; a liquid taking throttle valve is arranged on the liquid taking pipe;