Air conditioning system and control method thereof

Abstract

The application relates to the air conditioning technical field, and particularly provides an air conditioning system and a control method thereof. The air conditioning system comprises a first refrigerant circulation loop, a compressor, a condenser, a flash evaporator, an evaporator outer pipe, a first valve body, a second refrigerant pipeline, one end of the second refrigerant pipeline arranged between the compressor and the condenser, the other end arranged between the evaporator outer pipe and the first valve body, a second valve body arranged on the second refrigerant pipeline, a third refrigerant pipeline, one end of the third refrigerant pipeline connected with a liquid outlet of the flash evaporator, the other end arranged between the first valve body and the compressor, an evaporator inner pipe and a third valve body arranged on the third refrigerant pipeline, and heat exchange between the evaporator inner pipe and the evaporator outer pipe. The refrigerant pressure of the evaporator outer pipe is reduced through double-pipe heat exchange and the combination of the flash evaporator, so that the air conditioning system can quickly recover to high-efficiency heating after switching from defrosting to normal heating mode, and the normal heating efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioning, and specifically provides an air conditioning system and a control method thereof. BACKGROUND

[0002] When an air conditioning heat pump system is operated in heating mode in winter, frost will form on the outdoor unit due to evaporation heat absorption caused by long operation time, low outdoor temperature, high humidity, etc. The frost will cause low system efficiency, and the system should perform defrosting action at this time. If the four-way valve is used to reverse the heat flow for defrosting in the defrosting process, the indoor heat exchanger stops condensing heat release, and cannot release heat to the indoor in a short time, causing the indoor temperature to drop. To solve the above problems, part of the high-temperature and high-pressure refrigerant of the compressor is introduced into the indoor heat exchanger to provide heat for the indoor in the prior art, and another part of the high-temperature and high-pressure refrigerant is introduced into the outdoor heat exchanger to provide a heat source for defrosting, thereby realizing non-stop defrosting. However, after the non-stop defrosting mode ends, when switching to the conventional heating mode, the evaporation effect of the outdoor heat exchanger is poor in the initial period of the conventional heating mode, the heating efficiency is low, and a long time is required to reach the preset room temperature of the user.

[0003] Correspondingly, there is a need in the art for a new air conditioning system to solve the problem of poor heating effect of the existing air conditioning system after switching from the non-stop defrosting mode to the conventional heating mode. SUMMARY

[0004] The present application aims to solve the above technical problems, i.e., to solve the problem of poor heating effect of the conventional heating mode in the early stage after the non-stop defrosting mode of the existing air conditioning system ends.

[0005] In a first aspect, the present application provides an air conditioning system, comprising:

[0006] a first refrigerant circulation loop, wherein a compressor, a condenser, a flash evaporator, an evaporator outer pipe, and a first valve body are arranged on the first refrigerant circulation loop;

[0007] a second refrigerant pipeline, one end of which is arranged between the compressor and the condenser, and the other end of which is arranged between the evaporator outer pipe and the first valve body; a second valve body is arranged on the second refrigerant pipeline;

[0008] a third refrigerant pipeline, one end of which is connected with a liquid outlet of the flash evaporator, and the other end of which is arranged between the first valve body and the compressor; an evaporator inner pipe and a third valve body are arranged on the third refrigerant pipeline;

[0009] wherein heat exchange is performed between the evaporator inner pipe and the evaporator outer pipe.

[0010] In the above technical solution, in the non-stop defrosting mode, heat exchange is carried out between the inner tube of the evaporator and the outer tube of the evaporator, the inner tube liquid refrigerant absorbs the heat released by the outer tube gaseous refrigerant through double tube heat exchange, the condensation effect of the refrigerant in the outer tube of the evaporator is improved, and the pressure in the outer tube of the evaporator is preliminarily reduced. After switching to the conventional heating mode, the high-pressure characteristics of the high-pressure liquid refrigerant in the outer tube of the evaporator and the low-pressure characteristics of the flash evaporator are utilized, so that the high-pressure liquid refrigerant in the outer tube of the evaporator is sucked into the flash evaporator in a short time, the flash evaporator functions as a high-pressure liquid accumulator, so that the pressure in the outer tube of the evaporator is quickly restored to a suitable low pressure state. After switching from the non-stop defrosting mode to the conventional heating mode, the liquid refrigerant in the flash evaporator can smoothly enter the outer tube of the evaporator for normal evaporation and heat absorption, thereby improving the operating efficiency and heating effect of the conventional heating mode.

[0011] In the optional technical solution of the above air conditioning system, the air conditioning system further comprises a bypass pipeline, one end of the bypass pipeline is connected with the gas outlet of the flash evaporator, and the other end is connected with the air supplementing port of the compressor.

[0012] In the above technical solution, the gaseous refrigerant after flashing is returned to the compressor through the bypass pipeline to supplement air for the compressor.

[0013] In the optional technical solution of the above air conditioning system, a first throttling device is arranged between the condenser and the flash evaporator; and / or, a second throttling device is arranged between the flash evaporator and the outer tube of the evaporator; and / or, a third throttling device is arranged between the flash evaporator and the inner tube of the evaporator; and / or, a gas-liquid separator is arranged on the pipeline between the outer tube of the evaporator and the air inlet of the compressor.

[0014] In the above technical solution, the refrigerant is throttled and depressurized by the throttling device to reach a suitable pressure state, and the gas-liquid separator can prevent liquid refrigerant from entering the compressor to cause liquid hammer.

[0015] In the optional technical solution of the above air conditioning system, the outer tube of the evaporator comprises a plurality of outer tube branches, and the inner tube of the evaporator comprises a plurality of inner tube branches corresponding to the outer tube branches.

[0016] In the above technical solution, the heat exchange area between the inner tube and the outer tube is increased, and the heat exchange efficiency is improved.

[0017] In the optional technical solution of the above air conditioning system, the air conditioning system further comprises a four-way valve arranged on the first refrigerant circulation loop; and / or, the air conditioning system further comprises a fourth valve body arranged between the flash evaporator and the outer tube of the evaporator on the first refrigerant circulation loop.

[0018] In the technical scheme, the fourth valve body controls the communication between the condenser and the flash evaporator, and the four-way valve switches the flow direction of the refrigerant according to different functions of the air conditioner.

[0019] The application further provides a control method of the air conditioning system.

[0020] The first refrigerant circulation loop is provided with a compressor, a condenser, a flash evaporator, an evaporator outer pipe and a first valve body.

[0021] The second refrigerant pipe is provided with a second valve body.

[0022] The third refrigerant pipe is provided with an evaporator inner pipe and a third valve body.

[0023] The evaporator inner pipe and the evaporator outer pipe exchange heat.

[0024] The control method comprises the following steps.

[0025] Receiving an instruction of switching from the non-stop defrosting mode to the normal heating mode.

[0026] Controlling the first valve body and the second valve body to be closed, and the third valve body to be opened, and keeping for a first preset time length.

[0027] Controlling the first valve body to be opened, the third valve body to be closed, and keeping the second valve body closed.

[0028] In the technical scheme, when the air conditioning system is switched from the non-stop defrosting mode to the normal heating mode, the first valve body and the second valve body are controlled to be closed, and the third valve body is controlled to be opened, and kept for a first preset time length, during which the defrosting is stopped, and the refrigerant in the evaporator outer pipe is quickly sucked into the flash evaporator, so that the pressure in the evaporator outer pipe is quickly recovered to a suitable low pressure state, then the second valve body is kept closed, the first valve body is opened, and the third valve body is closed, and the air conditioning system is recovered to the normal heating mode, so that the liquid refrigerant in the flash evaporator can smoothly enter the evaporator outer pipe to be normally evaporated and heat absorbed, thereby improving the operation efficiency and heating effect of the air conditioning system after being switched from the non-stop defrosting mode to the normal heating mode.

[0029] In the control method of the air conditioning system, before the step of controlling the first valve body to be opened, the third valve body to be closed, and keeping the second valve body closed, the control method further comprises the following steps.

[0030] acquiring the pressure in the evaporator outer tube;

[0031] controlling the compressor frequency to decrease with the decrease of the pressure in the evaporator outer tube within the first preset time period; or,

[0032] a first throttling device is arranged between the condenser and the flash evaporator; before the step of "controlling the first valve body to open, the third valve body to close, and keeping the second valve body closed", the control method further comprises:

[0033] controlling the opening degree of the first throttling device to decrease or close within the first preset time period.

[0034] In the above technical solution, the high-pressure liquid refrigerant in the evaporator outer tube is timely sucked into the flash evaporator within the first preset time period, and the compressor frequency decreases with the decrease of the pressure in the evaporator outer tube, so as to prevent the compressor from being damaged due to the decrease of the return air volume, and the opening degree of the first throttling device is decreased to make the refrigerant in the evaporator outer tube quickly leave the evaporator.

[0035] In the above control method of the air conditioning system, the control method comprises:

[0036] receiving an instruction to run the non-stop defrosting mode;

[0037] controlling the second valve body and the third valve body to open, and the first valve body to close; or, the control method further comprises:

[0038] receiving an instruction to run the normal heating mode;

[0039] controlling the first valve body to open, and the second valve body and the third valve body to close.

[0040] In the above technical solution, when receiving the instruction to run the non-stop defrosting mode of the air conditioning system, the second valve body, the third valve body, and the fourth valve body are opened, and the first valve body is closed, part of the high-temperature and high-pressure refrigerant of the compressor enters the evaporator outer tube for defrosting, and the other part enters the condenser for indoor heating, and the two parts of the refrigerant become high-pressure liquid refrigerant after heat dissipation, and enter the flash evaporator for flashing.

[0041] After the non-stop defrosting mode runs for a period of time, the air conditioning system switches to the normal heating mode. In order to avoid the existence of high-pressure liquid refrigerant in the evaporator outer tube, which leads to poor evaporation effect in the initial time or increases the heating running time, the first valve body and the second valve body are first closed, and the third valve body and the fourth valve body are opened, and the opening is maintained for a first preset time period, and then the first valve body is opened and the third valve body is closed to normally run the normal heating.

[0042] In the control method of the air conditioning system, the outer tube of the evaporator comprises a plurality of outer tube branches, the inner tube of the evaporator comprises a plurality of inner tube branches corresponding to the outer tube branches for heat exchange, and the control method comprises:

[0043] acquiring the temperature of the refrigerant in the outer tube branch when the air conditioning system operates in the conventional heating mode;

[0044] controlling the third valve body to be opened when it is detected that the temperature of the outer tube branch exceeds the preset temperature;

[0045] adjusting the opening degree of the regulating valve of the inner tube branch corresponding to the outer tube branch according to the temperature of the outer tube branch.

[0046] In the above technical solution, when the air conditioning system operates in the conventional heating mode, if overheating of some outer tube branch is detected, it indicates that the refrigerant is insufficient and cannot efficiently absorb environmental heat. At this time, the third valve body is opened, the liquid refrigerant in the flash evaporator enters the inner tube branch of the evaporator after being throttled and depressurized by the third throttling device, and part of the refrigerant is supplemented on the corresponding inner tube side. The inner tube side refrigerant and the outer tube side refrigerant evaporate and absorb heat together, thereby reducing the outer tube temperature and increasing the heat absorption of the evaporator.

[0047] The higher the temperature of the outer tube branch, the more refrigerant is insufficient, and the smaller the heat absorption amount. Therefore, the opening degree of the regulating valve of the corresponding inner tube branch is larger to increase the heat absorption capacity of the inner tube branch. Conversely, the lower the temperature of the outer tube branch, the smaller the opening degree of the regulating valve of the inner tube branch, thereby reducing the refrigerant flow in the inner tube branch and reducing the heat absorption capacity of the inner tube branch.

[0048] The application further provides another control method of an air conditioning system, which comprises:

[0049] a first refrigerant circulation loop, wherein a compressor, a condenser, a flash evaporator, an evaporator outer tube and a first valve body are arranged on the first refrigerant circulation loop;

[0050] a second refrigerant loop, wherein one end of the second refrigerant loop is arranged between the compressor and the condenser, and the other end is arranged between the evaporator outer tube and the first valve body; and a second valve body is arranged on the second refrigerant loop;

[0051] a third refrigerant loop, wherein one end of the third refrigerant loop is connected with a liquid outlet of the flash evaporator, and the other end is arranged between the first valve body and the compressor; an evaporator inner tube and a third valve body are arranged on the third refrigerant loop;

[0052] wherein the evaporator inner tube and the evaporator outer tube exchange heat;

[0053] the control method comprises:

[0054] receiving an instruction to switch from the non-stop defrosting mode to the regular heating mode;

[0055] controlling the first valve body, the second valve body and the third valve body to be closed for a first preset time duration;

[0056] controlling the first valve body to be opened and keeping the second valve body and the third valve body closed.

[0057] In the above technical solution, when the air conditioning system switches from the non-stop defrosting mode to the regular heating mode, the first valve body, the second valve body and the third valve body are controlled to be closed, the fourth valve body is controlled to be opened and kept for a first preset time duration, the defrosting is stopped, the high-pressure refrigerant in the outer tube of the evaporator enters the flash evaporator, the flash evaporator supplies air to the compressor through the bypass pipeline, so that the refrigerant in the condenser can smoothly enter the outer tube of the evaporator to absorb heat when the regular heating is performed.

[0058] As understood by those skilled in the art, the air conditioning system of the present application comprises a first refrigerant circulation loop, a second refrigerant pipeline and a third refrigerant pipeline; the first refrigerant circulation loop is provided with a compressor, a condenser, a flash evaporator, an outer tube of an evaporator and a first valve body; the condenser is arranged in an indoor unit, the evaporator is arranged in an outdoor unit, and the evaporator comprises an outer tube and an inner tube; one end of the second refrigerant pipeline is arranged between the compressor and the condenser, and the other end is arranged between the outer tube of the evaporator and the first valve body; the second refrigerant circulation pipeline is provided with a second valve body;

[0059] one end of the third refrigerant pipeline is connected with a liquid outlet of the flash evaporator, and the other end is arranged between the first valve body and the compressor; the third refrigerant pipeline is provided with the inner tube of the evaporator and a third valve body; and heat exchange is performed between the inner tube of the evaporator and the outer tube.

[0060] In the above technical solution, in the non-stop defrosting mode, heat exchange is performed between the inner tube of the evaporator and the outer tube, the inner tube liquid refrigerant absorbs the heat released by the outer tube gaseous refrigerant through the double-tube heat exchange, the condensation effect of the refrigerant in the outer tube of the evaporator is improved, and the pressure in the outer tube of the evaporator is preliminarily reduced; after switching to the regular heating mode, the high-pressure characteristics of the high-pressure liquid refrigerant in the outer tube of the evaporator and the low-pressure characteristics of the flash evaporator are utilized, so that the high-pressure liquid refrigerant in the outer tube of the evaporator is sucked into the flash evaporator in a short time, the flash evaporator functions as a high-pressure liquid accumulator, so that the pressure in the outer tube of the evaporator is quickly restored to a suitable low pressure state; after switching from the non-stop defrosting mode to the regular heating mode, the liquid refrigerant in the flash evaporator can smoothly enter the outer tube of the evaporator to normally evaporate and absorb heat, and the operation efficiency and heating effect of the regular heating mode are improved. BRIEF DESCRIPTION OF DRAWINGS

[0061] The preferred embodiments of the present application will be described below with reference to the accompanying drawings, in which:

[0062] Figure 1 is a schematic diagram of the refrigerant flow in the non-stop defrosting mode of the air conditioning system of the present application;

[0063] Figure 2 is a schematic diagram of the refrigerant flow in the first preset time period when the air conditioning system of the present application is switched from the non-stop defrosting mode to the regular heating mode;

[0064] Figure 3 is a schematic diagram of the refrigerant flow in the regular heating mode of the air conditioning system of the present application;

[0065] Figure 4 is a schematic diagram of the refrigerant flow in the air conditioning system when the evaporator outer pipe branch is overheated;

[0066] Figure 5 is a schematic diagram of the structure of the evaporator of the present application;

[0067] Figure 6 is a main step flow chart of the control method of the air conditioning system of the present application;

[0068] Figure 7 is a step flow chart of one embodiment of the control method of the air conditioning system of the present application;

[0069] Figure 8 is a step flow chart of another embodiment of the control method of the air conditioning system of the present application.

[0070] List of reference signs:

[0071] 1, compressor; 2, condenser; 3, evaporator; 31, evaporator outer pipe; 311, first flow divider; 312, first flow collector; 32, evaporator inner pipe; 321, second flow divider; 322, second flow collector; 4, flash evaporator;

[0072] 51, first valve body; 52, second valve body; 53, third valve body; 54, fourth valve body;

[0073] 61, first throttling device; 62, second throttling device; 63, third throttling device;

[0074] 7, four-way valve. DETAILED DESCRIPTION

[0075] The preferred embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art will understand that the embodiments are only used to explain the technical principles of the present application and are not intended to limit the protection scope of the present application. Those skilled in the art can make adjustments as needed to adapt to specific application occasions. The control method of the present application can be applied to multi-split air conditioning systems, cabinet or ceiling type air conditioners, and other air conditioning systems. Those skilled in the art can set the application object as needed.

[0076] It should be noted that in the description of the present application, the terms "first", "second", "third" are only for the purpose of description and cannot be understood as indicating or implying relative importance.

[0077] In addition, it should be noted that in the description of the present application, unless otherwise specified and limited, the term "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection; it can be direct connection, or indirect connection through intermediate medium; it can be internal communication of two elements. Those skilled in the art can understand the specific meaning of the above-mentioned terms in the present application according to the specific circumstances.

[0078] The inventor found that when the existing air conditioning system is running in the non-stop defrosting mode, after the defrosting of the refrigerant in the evaporator by condensation and heat release, due to the incomplete heat release of the refrigerant, more high-pressure gas-liquid refrigerant is formed after condensation. After the system switches from the defrosting mode to the regular heating mode, due to the unstable pressure in the evaporator, the low-pressure liquid refrigerant from the condenser enters the evaporator, which leads to poor heat exchange of the low-pressure liquid refrigerant from the condenser, and further leads to an increase in the heating running time and poor heating effect.

[0079] To solve the problem of poor heating effect of the existing air conditioning system after switching from the non-stop defrosting mode to the regular heating mode, the air conditioning system of the present application comprises a first refrigerant circulation loop, a second refrigerant pipeline and a third refrigerant pipeline.

[0080] Referring to Figure 3 , the first refrigerant circulation loop is provided with a compressor 1, a condenser 2, a flash evaporator 4, an evaporator outer pipe 31 and a first valve body 51. The condenser 2 is arranged in the indoor unit, and the evaporator 3 is arranged in the outdoor unit. Referring to Figure 5 , the evaporator 3 comprises the evaporator outer pipe 31 and the evaporator inner pipe 32 in the form of a double-pipe. Referring to Figure 3, the first refrigerant circulation loop can realize indoor normal heating, when the normal heating mode is run, the first valve body 51 is opened, the refrigerant of the outlet of the compressor 1 enters the indoor condenser 2 to provide heat for the indoor, the refrigerant of the outlet of the condenser 2 enters the flash evaporator 4 to flash, and then the liquid refrigerant in the flash evaporator 4 enters the evaporator outer pipe 31 to absorb heat and gasify and returns to the compressor 1.

[0081] Referring to Figure 1 , one end of the second refrigerant pipeline is arranged between the outlet of the compressor 1 and the condenser 2, and the other end is arranged between the evaporator outer pipe 31 and the first valve body 51, and the second valve body 52 is arranged on the second refrigerant pipeline;

[0082] One end of the third refrigerant pipeline is connected with the liquid outlet of the flash evaporator 4, and the other end is arranged between the first valve body 51 and the gas inlet of the compressor 1; the evaporator inner pipe 32 and the third valve body 53 are arranged on the third refrigerant pipeline; and heat exchange is carried out between the evaporator inner pipe 32 and the evaporator outer pipe 31.

[0083] Referring to Figure 1 , when the air conditioning system is run in the non-stop defrosting mode, the second valve body 52 and the third valve body 53 are opened, the first valve body 51 is closed, part of the high-temperature and high-pressure gaseous refrigerant of the outlet of the compressor 1 enters the outdoor evaporator outer pipe 31 to provide heat for defrosting, and the other part of the high-temperature and high-pressure gaseous refrigerant enters the indoor condenser 2 to provide heat for the indoor, so that indoor heating and outdoor defrosting are realized, the refrigerant in the evaporator 3 and the condenser 2 releases heat and enters the flash evaporator 4 to flash, the gaseous refrigerant and the liquid refrigerant are separated and the pressure of the refrigerant is reduced, then the liquid refrigerant after flashing enters the evaporator inner pipe 32, heat exchange is carried out between the evaporator inner pipe 32 and the evaporator outer pipe 31, the refrigerant in the evaporator inner pipe 32 absorbs the heat released by the refrigerant in the evaporator outer pipe 31, so that the condensation effect of the refrigerant in the evaporator outer pipe 31 is improved, the pressure in the evaporator outer pipe 31 is preliminarily reduced, and the refrigerant heat absorption amount of the evaporator is increased.

[0084] After receiving the instruction of switching the air conditioning system from the non-stop defrosting mode to the normal heating mode, the first valve body 51 and the second valve body 52 are closed, and the third valve body 53 is opened, the high-pressure characteristics of the high-pressure liquid refrigerant in the evaporator outer pipe 31 and the low-pressure characteristics of the flash evaporator are utilized, the flash evaporator 4 plays a role of a high-pressure liquid accumulator, the refrigerant in the evaporator outer pipe 31 is quickly sucked into the flash evaporator 4, so that the pressure in the evaporator outer pipe 31 is quickly restored to a suitable low pressure state, then the first valve body 51 is controlled to be opened, the third valve body 53 is controlled to be closed, and the second valve body 52 is controlled to be closed, the air conditioning system returns to the normal heating mode, at this time, the pressure of the evaporator outer pipe 31 is low, the liquid refrigerant in the flash evaporator 4 can enter the evaporator outer pipe 31 to normally evaporate and absorb heat, and then the operation efficiency and the heating effect of the system after switching from the non-stop defrosting mode to the normal heating mode are improved.

[0085] The present application reduces the pressure of the outer tube 31 of the evaporator by heat exchange between the inner and outer tubes of the evaporator and the high-pressure refrigerant sucked into the outer tube 31 of the evaporator by the flash evaporator 4, so that after the system is switched from defrosting to normal heating, the low-pressure liquid refrigerant in the condenser 2 can smoothly enter the outer tube 31 of the evaporator, the outer tube 31 of the evaporator evaporates quickly and efficiently, reducing the influence of the high-pressure refrigerant in the outer tube 31 of the evaporator on normal heating, so that the normal heating mode can quickly recover to efficient heating in the early stage of operation, improve the normal heating effect, and shorten the heating time.

[0086] Referring to Figures 1 to 3 In one possible implementation, the air conditioning system of the present application comprises a first refrigerant circulation loop, a second refrigerant pipeline, a third refrigerant pipeline and a bypass pipeline; referring to Figure 3 The first refrigerant circulation loop is provided with a compressor 1, a four-way valve 7, a condenser 2, a first throttling device 61, a flash evaporator 4, a second throttling device 62, a fourth valve body 54, an evaporator outer tube 31 and a first valve body 51. One end of the bypass pipeline is connected to the gas outlet of the flash evaporator 4, and the other end is connected to the air supplementing port of the compressor 1.

[0087] In the normal heating mode, the high-temperature and high-pressure gaseous refrigerant of the compressor 1 enters the condenser 2 to heat the room, and the liquid refrigerant in the condenser 2 enters the flash evaporator 4 after throttling by the first throttling device 61. The liquid refrigerant after flashing of the refrigerant enters the evaporator 3 after throttling by the second throttling device 62, and then returns to the compressor 1. The gaseous refrigerant after flashing of the refrigerant returns to the compressor 1 through the bypass pipeline to supplement air for the compressor 1.

[0088] The refrigerant of the condenser 2 enters the flash evaporator 4 after throttling and pressure reduction by the first throttling device 61, so that the pressure of the refrigerant is reduced to a pressure state suitable for flash operation, so that the refrigerant can evaporate quickly in the flash evaporator 4 and generate more low-temperature and low-pressure steam, which can be further compressed by the compressor 1 to improve the refrigeration capacity of the system.

[0089] The liquid refrigerant after flashing enters the second throttling device 62 to throttle and reduce the pressure, so as to further reduce the pressure of the refrigerant and avoid the problem of wet compression. In a low-pressure state, the refrigerant is more easily evaporated in the evaporator to absorb heat, and the throttling device helps to maintain the pressure balance between the components of the refrigeration system, ensuring stable operation of the system.

[0090] After switching from the non-stop defrosting mode to the normal heating mode, the opening of the first throttling device 61 is reduced or the first throttling device 61 is directly closed to speed up the rapid exit of the high-pressure refrigerant in the outer tube 31 of the evaporator.

[0091] The fourth valve body 54 can control the communication between the condenser 2 and the flash evaporator 4, and the four-way valve 7 can switch the flow direction of the refrigerant according to different functions of the air conditioner.

[0092] With reference to Figure 1 One end of the second refrigerant pipeline is arranged between the outlet of the compressor 1 and the condenser 2, and the other end is arranged between the evaporator outer pipe 31 and the first valve body 51, and the second valve body 52 is arranged on the second refrigerant pipeline;

[0093] One end of the third refrigerant pipeline is connected to the liquid outlet of the flash evaporator 4, and the other end is arranged between the first valve body 51 and the compressor 1; the third refrigerant pipeline is provided with the third throttling device 63, the evaporator inner pipe 32 and the third valve body 53; the evaporator inner pipe 32 and the evaporator outer pipe 31 exchange heat. A gas-liquid separator (not shown in the figure) is arranged on the pipeline between the evaporator outer pipe 31 and the compressor inlet to avoid liquid refrigerant entering the compressor 1 to cause liquid impact.

[0094] In the non-stop defrosting mode, the refrigerant in the evaporator outer pipe 31 enters the flash evaporator 4 after being throttled and reduced in pressure at the second throttling device 62, so that the pressure of the refrigerant is reduced to a pressure state suitable for flash evaporation. The liquid refrigerant after flash evaporation in the flash evaporator 4 is throttled and reduced in pressure by the third throttling device 63, which helps to enter the evaporator inner pipe 32 for normal evaporation and heat absorption.

[0095] When the non-stop defrosting mode is switched to the normal heating mode, the evaporator inner and outer pipes exchange heat, the flash evaporator 4 absorbs the refrigerant, the second throttling device 62 and the compressor 1 suction work together to reduce the pressure of the evaporator outer pipe 31. In the normal heating mode, the liquid refrigerant in the condenser 2 can enter the evaporator outer pipe 31 for evaporation and heat absorption more quickly, which improves the heat absorption efficiency of the evaporator and is beneficial to improve the operating efficiency of the heat pump system after switching the operating mode.

[0096] Further, the evaporator outer pipe 31 includes a plurality of outer pipe branches, and the evaporator inner pipe 32 includes a plurality of inner pipe branches corresponding to the outer pipe branches and sleeved on the outer pipe branches. The refrigerant in the outer pipe branches and the inner pipe branches can exchange heat to increase the heat exchange area and provide heat exchange efficiency. The two ends of the outer pipe branches are connected with the first flow divider 311 and the first flow collector 312; the two ends of the inner pipe branches are connected with the second flow divider 321 and the second flow collector 322. The flow divider is used to distribute the refrigerant to each branch, and the flow collector is used to concentrate the refrigerant in each branch.

[0097] The outer pipe branch is sleeved on the inner pipe branch, and a gap for refrigerant flow is left between the two, and an adjustable valve capable of adjusting the opening degree is arranged in the inner pipe branch. In the conventional heating mode, due to the influence of factors such as flow distribution and heat exchange coefficient, the evaporator often has unreasonable liquid distribution in different branches, which may cause overheating of some outer pipe branches. The overheated branch indicates that the refrigerant is insufficient and cannot efficiently absorb environmental heat. If it is detected that the outer pipe branch of the evaporator is overheated due to uneven liquid distribution, the third valve body 53 and the third throttling valve 63 are opened, so that the liquid refrigerant enters the inner pipe branch corresponding to the overheated outer pipe branch, and the refrigerant flow entering the inner pipe branch is adjusted by adjusting the opening degree of the valve body, so that the heat absorption of the inner and outer pipes is reduced, and the heat absorption of the evaporator is increased.

[0098] As described in the first paragraph of this section, the above-mentioned embodiments are only used to illustrate the principles of the present application and are not intended to limit the protection scope of the present application. Those skilled in the art can adjust the above-mentioned structure without deviating from the principles of the present application, so that the present application can be applied to more specific application scenarios.

[0099] In addition, the present application also provides a control method of an air conditioning system, which has the air conditioning system described in any of the above-mentioned embodiments. Further, the air conditioning system further comprises an evaporator temperature sensor and an evaporator pressure sensor, the evaporator temperature sensor is used to detect the temperature of each outer pipe branch of the evaporator 3, but the present application does not make any limitation on the setting position of the evaporator temperature sensor, which can be set at the end or middle of the outer pipe branch, and those skilled in the art can set it according to the needs. The evaporator pressure sensor is used to detect the pressure in the outer pipe 31 of the evaporator, and the present application does not make any limitation on the setting position of the evaporator pressure sensor, which can be set at the end or middle of the outer pipe branch, and those skilled in the art can set it according to the needs.

[0100] The air conditioning system of the present application further comprises a controller, which can acquire the evaporator outer pipe temperature and pressure, and the instructions sent by the user, and the controller can control the operating state of the air conditioning system, such as refrigeration or heating operation, frequency of the compressor, opening degree of the throttling device, opening degree of the valve body, etc.

[0101] Reference Figure 7 , specifically, the main steps of the control method of the air conditioning system include:

[0102] Step S10: receiving an instruction to switch from the non-stop defrosting mode to the conventional heating mode;

[0103] Step S20: control the first valve body and the second valve body to be closed, and the third valve body to be opened, and continue for a first preset time length;

[0104] Step S30: control the first valve body to open, the third valve body to close, and keep the second valve body closed.

[0105] The instruction of running the non-stop defrosting mode or the regular heating mode is an instruction sent by a user through a terminal device such as a remote controller, a button on an air conditioner panel, or a mobile phone APP, or an instruction automatically sent after the air conditioning system finishes a program, for example, an instruction of running the regular heating mode is automatically sent after the air conditioning system finishes defrosting in the non-stop defrosting mode. After the instruction of running the mode is sent, the air conditioning system receives the corresponding instruction of running the mode.

[0106] To quickly reduce the pressure of the outer pipe 31 of the evaporator, when the air conditioning system switches from the non-stop defrosting mode to the regular heating mode, the first valve body 51 and the second valve body 52 are controlled to close, and the third valve body 53 is controlled to open for a first preset time duration, during which the defrosting is stopped, and the refrigerant in the outer pipe 31 of the evaporator is quickly sucked into the flash evaporator 4, so that the pressure in the outer pipe 31 of the evaporator is quickly restored to a suitable low pressure state, then the second valve body 52 is kept closed, the first valve body 51 is opened, and the third valve body 53 is closed, and the air conditioning system returns to the regular heating mode, so that the liquid refrigerant in the flash evaporator 4 can smoothly enter the outer pipe 31 of the evaporator for normal evaporation and heat absorption, thereby improving the running efficiency and heating effect of the system after switching from the non-stop defrosting mode to the regular heating mode.

[0107] Alternatively, the specific value of the first preset time duration is 1 second to 20 seconds, which can be 2 seconds, 3 seconds, 5 seconds, 8 seconds, 10 seconds, or 15 seconds, etc. Those skilled in the art can set the first preset time duration according to the needs, and the present application does not make any limitation thereon, and all fall within the protection scope of the present application.

[0108] Reference Figure 7 In a possible implementation, the specific steps of the control method of the air conditioning system further include:

[0109] Step S41: receiving the instruction of running the non-stop defrosting mode.

[0110] Step S42: controlling the second valve body, the third valve body, and the fourth valve body to open, and the first valve body to close until the defrosting is finished.

[0111] When the instruction of running the non-stop defrosting mode of the air conditioning system is received, the second valve body 52, the third valve body 53 and the fourth valve body 54 are opened, the first valve body 51 is closed, a part of the high-temperature and high-pressure refrigerant of the compressor 1 enters the evaporator outer pipe 31 for defrosting, and another part enters the condenser 2 for indoor heating. After the two parts of refrigerant are radiated, they become high-pressure liquid refrigerant, and enter the flash evaporator 4 to separate the gaseous refrigerant and the liquid refrigerant and reduce the pressure of the refrigerant. The gaseous refrigerant returns to the compressor 1 for air supply through the bypass pipeline, and the low-pressure liquid refrigerant in the flash evaporator 4 enters the evaporator inner pipe 32 and absorbs the heat of the refrigerant in the evaporator outer pipe 31 to reduce the pressure of the evaporator outer pipe 31.

[0112] After step S42, the control method further comprises:

[0113] Step S43: receiving an instruction of running the normal heating mode;

[0114] Step S44: controlling the first valve body and the second valve body to be closed, and the third valve body and the fourth valve body to be opened, and maintaining for a first preset time length;

[0115] Step S45: acquiring the pressure in the evaporator outer pipe;

[0116] Step S46: controlling the frequency of the compressor to decrease with the decrease of the pressure in the evaporator outer pipe, and controlling the opening degree of the first throttling device to decrease or be closed, within the first preset time length;

[0117] Step S47: controlling the first valve body to be opened, the third valve body to be closed, the second valve body to be maintained to be closed, the fourth valve body to be opened, controlling the frequency of the compressor to increase, and controlling the opening degree of the first throttling device to increase.

[0118] After the non-stop defrosting mode runs for a period of time, the air conditioning system is switched to the normal heating mode. In order to avoid the existence of high-pressure liquid refrigerant in the evaporator outer pipe 31, which leads to poor evaporation effect in the initial time or increases the heating running time, the first valve body 51 and the second valve body 52 are first controlled to be closed, and the third valve body 53 and the fourth valve body 54 are controlled to be opened and maintained for a first preset time length, so as to stop the defrosting of the evaporator 3. The high-pressure liquid refrigerant in the evaporator outer pipe 31 is timely sucked into the flash evaporator 4 within the first preset time length. During this period, the frequency of the compressor decreases with the decrease of the pressure in the evaporator outer pipe 31, so as to prevent the decrease of the air return amount from causing damage to the compressor. The opening degree of the first throttling device 41 is also decreased, so that the refrigerant in the evaporator outer pipe 31 quickly leaves the evaporator.

[0119] After the pressure of the refrigerant in the evaporator outer pipe 31 is decreased, the first valve body 51 is opened and the third valve body 53 is closed to normally run the normal heating mode, so that the liquid refrigerant after flashing enters the evaporator outer pipe 31 to normally evaporate and absorb heat, so as to improve the evaporation effect and the heating efficiency of the normal heating mode.

[0120] Referring to Figure 8 Further, the control method further comprises:

[0121] Step S51: obtaining the temperature of the outer tube branch of the evaporator when the air conditioning system operates in the normal heating mode;

[0122] Step S52: when it is detected that the temperature of the outer tube branch exceeds the preset temperature, controlling the third valve body to open;

[0123] Step S53: adjusting the opening degree of the adjusting valve corresponding to the inner tube branch of the outer tube branch according to the temperature of the outer tube branch;

[0124] Step S54: when the temperature of the outer tube branch does not exceed the preset temperature, controlling the third valve body to close, and the adjusting valve corresponding to the inner tube branch is closed.

[0125] When the air conditioning system operates in the normal heating mode, if it is detected that some outer tube branch is overheated, it indicates that there is a lack of refrigerant and the environmental heat cannot be efficiently absorbed. At this time, the third valve body 53 is opened, the liquid refrigerant in the flash evaporator 4 enters the inner tube branch of the evaporator 3 after being throttled and reduced in pressure by the third throttling device 63, and part of the refrigerant is supplemented on the corresponding inner tube side. The inner tube side refrigerant and the outer tube side refrigerant jointly evaporate and absorb heat, thereby reducing the outer tube temperature and increasing the heat absorption amount of the evaporator 3.

[0126] The higher the temperature of the outer tube branch, the more refrigerant is lacking, and the smaller the heat absorption amount. Therefore, the opening degree of the adjusting valve of the corresponding inner tube branch is larger to increase the heat absorption capacity of the inner tube branch. Conversely, the lower the temperature of the outer tube branch, the smaller the opening degree of the adjusting valve of the inner tube branch, thereby reducing the refrigerant flow in the inner tube branch and reducing the heat absorption capacity of the inner tube branch. When the temperature of the outer tube branch returns to normal, the third valve body 53 and the adjusting valve of the corresponding inner tube branch are closed, and heat exchange is only performed through the outer tube branch.

[0127] When the air conditioning system operates in the non-stop defrosting mode, the adjusting valve of the inner tube branch is controlled to be in a fully open state to improve the heat exchange capacity between the inner tube branch and the outer tube branch.

[0128] In another embodiment, the control method comprises:

[0129] Step: receiving an instruction to switch from the non-stop defrosting mode to the normal heating mode;

[0130] Step: controlling the first valve body, the second valve body and the third valve body to be closed for a first preset time period;

[0131] Step: controlling the first valve body to be opened, and keeping the second valve body and the third valve body closed.

[0132] When the air conditioning system switches from the non-stop defrosting mode to the normal heating mode, the first valve body 51, the second valve body 52 and the third valve body 53 are closed, the fourth valve body 54 is opened and kept for a first preset time length, the defrosting is stopped, the high-pressure refrigerant in the evaporator outer pipe 31 enters the flash evaporator 4, the flash evaporator 4 supplies air to the compressor 1 through the bypass pipeline, so that the refrigerant in the condenser can smoothly enter the evaporator outer pipe 31 to absorb heat when the normal heating is performed.

[0133] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after the changes or replacements will all fall within the protection scope of the present application.

Claims

1. A control method of an air conditioning system, characterized by, The air conditioning system comprises: A first refrigerant circulation loop; a compressor, a condenser, a flash evaporator, an evaporator outer pipe, a first valve body are arranged on the first refrigerant circulation loop; A second refrigerant pipeline; one end of the second refrigerant pipeline is arranged between the compressor and the condenser, and the other end is arranged between the evaporator outer pipe and the first valve body; a second valve body is arranged on the second refrigerant pipeline; A third refrigerant pipeline; one end of the third refrigerant pipeline is connected with a liquid outlet of the flash evaporator, and the other end is arranged between the first valve body and the compressor; an evaporator inner pipe and a third valve body are arranged on the third refrigerant pipeline; The evaporator inner pipe and the evaporator outer pipe exchange heat; The control method comprises: Receiving an instruction of switching from a non-stop defrosting mode to a regular heating mode; Controlling the first valve body and the second valve body to be closed, and the third valve body to be opened, and continuing for a first preset time length; Controlling the first valve body to be opened, the third valve body to be closed, and the second valve body to be kept closed.

2. The control method of the air conditioning system according to claim 1, characterized by, Before the step of "controlling the first valve body to be opened, the third valve body to be closed, and the second valve body to be kept closed", the control method further comprises: Obtaining the pressure in the evaporator outer pipe; In the first preset time length, controlling the compressor frequency to decrease with the decrease of the pressure in the evaporator outer pipe; or, A first throttling device is arranged between the condenser and the flash evaporator; before the step of "controlling the first valve body to be opened, the third valve body to be closed, and the second valve body to be kept closed", the control method further comprises: In the first preset time length, controlling the opening degree of the first throttling device to decrease or be closed.

3. The control method of the air conditioning system according to claim 1, characterized by, The control method comprises: Receiving an instruction of running a non-stop defrosting mode; Controlling the second valve body and the third valve body to be opened, and the first valve body to be closed; or, the control method further comprises: Receiving an instruction of running a regular heating mode; Controlling the first valve body to be opened, and the second valve body and the third valve body to be closed.

4. The control method of the air conditioning system according to claim 1, characterized by, The evaporator outer pipe comprises a plurality of outer pipe branches, and the evaporator inner pipe comprises a plurality of inner pipe branches corresponding to the outer pipe branches for heat exchange; the control method comprises: Obtaining the temperature of the refrigerant in the outer pipe branches when the air conditioning system runs in the regular heating mode; When it is detected that the temperature of an outer pipe branch exceeds a preset temperature, controlling the third valve body to be opened; Adjusting the opening degree of the regulating valve of the inner pipe branch corresponding to the outer pipe branch according to the temperature of the outer pipe branch.

5. A control method of an air conditioning system, characterized by, The air conditioning system comprises: A first refrigerant circulation loop; a compressor, a condenser, a flash evaporator, an evaporator outer pipe, a first valve body are arranged on the first refrigerant circulation loop; A second refrigerant pipeline; one end of the second refrigerant pipeline is arranged between the compressor and the condenser, and the other end is arranged between the evaporator outer pipe and the first valve body; a second valve body is arranged on the second refrigerant pipeline; A third refrigerant pipeline; one end of the third refrigerant pipeline is connected with a liquid outlet of the flash evaporator, and the other end is arranged between the first valve body and the compressor; an evaporator inner pipe and a third valve body are arranged on the third refrigerant pipeline; Heat exchange is performed between the evaporator inner tube and the evaporator outer tube; The control method comprises: Receiving an instruction to switch from a no-stop defrosting mode to a regular heating mode; Controlling the first valve body, the second valve body and the third valve body to be closed for a first preset time length; Controlling the first valve body to be opened, and keeping the second valve body and the third valve body closed.

Images