Air conditioning unit and control method thereof

Abstract

The present invention discloses an air conditioning unit and a control method thereof, wherein the air conditioning unit comprises: a first heat exchange system, comprising: a first compressor, a first four-way valve, a first condenser, a first electronic expansion valve and a first evaporator connected in sequence; a second heat exchange system, comprising: a second compressor, a second four-way valve, a second condenser, a second electronic expansion valve and a second evaporator connected in sequence; an intermediate heat exchanger, a first end of which is connected to the first four-way valve, and a second end of which is connected to a first connection point on a pipeline between the first condenser and the first electronic expansion valve; wherein the first condenser, the second condenser and the intermediate heat exchanger are arranged in parallel. The present invention solves the problem of easy frost formation of the air conditioning unit during low-temperature heating in the prior art, and improves the operating stability of the air conditioning unit and the user comfort.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to an air conditioning unit and a control method thereof. Background Art

[0002] When the air conditioning unit is in heating mode under low temperature conditions, due to the low outdoor temperature and high humidity, frost is easy to form on the surface of the outdoor heat exchanger, which will reduce the heat exchange effect of the system.

[0003] At present, the defrosting method commonly used in heat pump (air conditioning) systems is: the compressor is shut down, then the four-way valve is reversed, and then the compressor is started for defrosting. Frequent start and stop will increase the failure rate of the compressor, and there is no heating output indoors during the defrosting process, which will seriously affect the heating effect of the heat pump, reduce the heating amount, and reduce the comfort of the air conditioner.

[0004] With regard to the problem in the related art that air-conditioning units are prone to frosting during low-temperature heating, no effective solution has been proposed so far. Summary of the invention

[0005] The present invention provides an air conditioning unit and a control method thereof, so as to at least solve the problem in the prior art that the air conditioning unit is prone to frosting during low-temperature heating.

[0006] To solve the above technical problems, according to one aspect of an embodiment of the present invention, an air conditioning unit is provided, comprising:

[0007] The first heat exchange system comprises: a first compressor, a first four-way valve, a first condenser, a first electronic expansion valve and a first evaporator which are connected in sequence;

[0008] The second heat exchange system comprises: a second compressor, a second four-way valve, a second condenser, a second electronic expansion valve and a second evaporator which are connected in sequence;

[0009] An intermediate heat exchanger, a first end of which is connected to the first four-way valve, and a second end of which is connected to a first connection point disposed on the pipeline between the first condenser and the first electronic expansion valve;

[0010] Among them, the first condenser, the second condenser and the intermediate heat exchanger are arranged in parallel.

[0011] Furthermore, the intermediate heat exchanger is located on the outdoor side, and the air conditioning unit further comprises: an outdoor fan, which is arranged in parallel with the first condenser, the second condenser and the intermediate heat exchanger.

[0012] Furthermore, it also includes:

[0013] A solenoid valve is located on the pipeline between the first end of the intermediate heat exchanger and the first four-way valve;

[0014] The auxiliary electronic expansion valve is located on the pipeline between the second end of the intermediate heat exchanger and the first connection point.

[0015] Furthermore, the first heat exchange system also includes: a first filter and / or a second filter; wherein the first filter is located on the pipeline between the first condenser and the first electronic expansion valve, and the second filter is located on the pipeline between the first electronic expansion valve and the first evaporator; the second heat exchange system also includes: a third filter and / or a fourth filter; wherein the third filter is located on the pipeline between the second condenser and the second electronic expansion valve, and the fourth filter is located on the pipeline between the second electronic expansion valve and the second evaporator.

[0016] Furthermore, it also includes: an indoor fan; a first evaporator, a second evaporator and an indoor fan are arranged in parallel front and back.

[0017] Furthermore, the outdoor fan is a steerable fan.

[0018] According to another aspect of an embodiment of the present invention, there is provided an air conditioning unit control method, which is applied to the air conditioning unit as described above, and the method comprises:

[0019] Detect outdoor ambient temperature and set operating mode;

[0020] Determine the operation mode of the air conditioning unit according to the outdoor ambient temperature and the set operation mode;

[0021] Control the operation of the air conditioning unit according to the operation mode.

[0022] Furthermore, the setting operation mode at least includes: cooling mode and heating mode; the operation mode at least includes: conventional cooling mode, high temperature cooling mode, conventional heating mode, and low temperature heating mode; the operation mode of the air-conditioning unit is determined according to the outdoor ambient temperature and the setting operation mode, including:

[0023] When the operating mode is set to the cooling mode and the outdoor ambient temperature is less than or equal to the first preset temperature, determining that the operating mode of the air-conditioning unit is the conventional cooling mode;

[0024] When the operating mode is set to the cooling mode and the outdoor ambient temperature is greater than a first preset temperature, determining that the operating mode of the air-conditioning unit is the high-temperature cooling mode;

[0025] When the operating mode is set to the heating mode and the outdoor ambient temperature is greater than the second preset temperature, determining that the operating mode of the air-conditioning unit is the conventional heating mode;

[0026] When the operating mode is set to the heating mode and the outdoor ambient temperature is less than or equal to the second preset temperature, the operating mode of the air-conditioning unit is determined to be the low-temperature heating mode; wherein the first preset temperature is greater than the second preset temperature.

[0027] Further, controlling the operation of the air conditioning unit according to the operation mode includes:

[0028] When the operation mode of the air-conditioning unit is the conventional cooling mode, the solenoid valve and the auxiliary electronic expansion valve are controlled to be disconnected, and the first heat exchange system and the second heat exchange system are controlled to operate in the cooling mode;

[0029] When the operation mode of the air-conditioning unit is the high-temperature cooling mode, the solenoid valve and the auxiliary electronic expansion valve are controlled to be closed, and the first heat exchange system and the second heat exchange system are controlled to operate in the cooling mode;

[0030] When the operation mode of the air-conditioning unit is the conventional heating mode, the solenoid valve and the auxiliary electronic expansion valve are controlled to be disconnected, and the first heat exchange system and the second heat exchange system are controlled to operate in the heating mode;

[0031] When the operation mode of the air-conditioning unit is the low-temperature heating mode, the solenoid valve and the auxiliary electronic expansion valve are controlled to be closed, and the first heat exchange system and the second heat exchange system are controlled to operate in the heating mode.

[0032] Furthermore, when the operation mode of the air-conditioning unit is a low-temperature heating mode, and after the operation of the air-conditioning unit is controlled according to the operation mode, the method further includes:

[0033] Detect the opening of the auxiliary electronic expansion valve;

[0034] When the opening of the auxiliary electronic expansion valve reaches a preset maximum opening, detecting the coil temperature of the first condenser and the coil temperature of the second condenser;

[0035] When the coil temperature of the first condenser is lower than the preset frosting temperature, the second heat exchange system is controlled to operate in a cooling mode;

[0036] When the coil temperature of the second condenser is lower than the preset frosting temperature, the first heat exchange system is controlled to operate in a cooling mode, and the outdoor fan is controlled to reverse.

[0037] According to another aspect of an embodiment of the present invention, there is provided a storage medium comprising computer executable instructions, wherein the computer executable instructions are used to execute the air conditioning unit control method as described above when executed by a computer processor.

[0038] In the present invention, a frost-free, continuous heating multi-system air conditioning unit is provided. In addition to the dual systems, namely the first heat exchange system and the second heat exchange system, the air conditioning unit also includes an intermediate heat exchanger. The first condenser, the second condenser and the intermediate heat exchanger are arranged in parallel front and back, and the intermediate heat exchanger is located at the front or rear side. The intermediate heat exchanger can increase the temperature of the air entering the outdoor evaporator, avoid the evaporation temperature being too high, causing the unit to frost, and thus avoid the problem of the air conditioning unit being shut down due to defrosting, thereby improving the operating stability of the air conditioning unit and the user comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic diagram of an optional structure of an air conditioning unit according to an embodiment of the present invention;

[0040] Figure 2 is an optional flow chart of an air conditioning unit control method according to an embodiment of the present invention;

[0041] Figure 3 is another optional flow chart of the air conditioning unit control method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

[0043] Example 1

[0044] In a preferred embodiment 1 of the present invention, an air conditioning unit is provided. Specifically, Figure 1 An optional structural diagram of the air conditioning unit is shown, such as Figure 1 As shown, the air conditioning unit includes:

[0045] The first heat exchange system comprises: a first compressor 1, a first four-way valve 2, a first condenser 3, a first electronic expansion valve 4 and a first evaporator 5 which are connected in sequence;

[0046] The second heat exchange system comprises: a second compressor 6, a second four-way valve 7, a second condenser 8, a second electronic expansion valve 9 and a second evaporator 10 which are connected in sequence;

[0047] The intermediate heat exchanger 11 has a first end connected to the first four-way valve 2 and a second end connected to a first connection point on the pipeline between the first condenser 3 and the first electronic expansion valve 4;

[0048] Among them, the first condenser 3, the second condenser 8 and the intermediate heat exchanger 11 are arranged in parallel, as long as it is achieved that when the fan blows air to the intermediate heat exchanger 11, the air outlet from the intermediate heat exchanger 11 passes through the first condenser 3 and the second condenser 8. Preferably, the first condenser 3, the second condenser 8 and the intermediate heat exchanger 11 are arranged in parallel front and back, and the intermediate heat exchanger 11 is located at the frontmost or rearmost side of the three, that is, the intermediate heat exchanger 11 is not arranged between the first condenser 3 and the second condenser 8. Figure 1It is shown that the intermediate heat exchanger 11 is located on one side of the first condenser 3, and of course the intermediate heat exchanger 11 can also be located on one side of the second condenser 8. In addition, the first heat exchange system and the second heat exchange system can be interchangeable, that is, the intermediate heat exchanger 11 can be connected to the four-way valve and condenser of the second heat exchange system.

[0049] In the above embodiment, a frost-free, continuous heating multi-system air conditioning unit is provided. In addition to the dual systems, namely the first heat exchange system and the second heat exchange system, the air conditioning unit also includes an intermediate heat exchanger 11. The first condenser 3, the second condenser 8 and the intermediate heat exchanger 11 are arranged in parallel front and back, and the intermediate heat exchanger 11 is located at the front or rear side. The intermediate heat exchanger 11 can increase the temperature of the air entering the outdoor evaporator, avoid the evaporation temperature being too high, causing the unit to frost, and thus avoid the problem of the air conditioning unit being shut down due to defrosting, thereby improving the operating stability of the air conditioning unit and the user comfort.

[0050] In the present air-conditioning unit, the intermediate heat exchanger 11 is located on the outdoor side. In addition, the air-conditioning unit further comprises an outdoor fan 12 which is arranged in parallel with the first condenser 3 , the second condenser 8 and the intermediate heat exchanger 11 . Figure 1 It is shown that the outdoor fan 12 is located on one side of the intermediate heat exchanger 11. Of course, the outdoor fan 12 can also be located on one side of the second condenser 8. In addition, the outdoor fan 12 is a steerable fan. The motor can be turned to blow air to the intermediate heat exchanger 11 or to blow air in the opposite direction. The airflow can be reversed when rotating in the positive and negative directions. When the outdoor fan 12 is located on one side of the intermediate heat exchanger 11 and the fan blows air to the intermediate heat exchanger 11, the air passes through the intermediate heat exchanger 11, the first condenser 3 and the second condenser 8 in sequence. Compared with conventional dual-system or multi-system air-conditioning units in which each outdoor condenser corresponds to an axial flow fan, only one outdoor fan 12 is used in this air-conditioning unit, which saves costs, and the heat of the intermediate heat exchanger 11 can be adjusted to the temperature at the outdoor condenser through the fan to avoid frost.

[0051] In order to realize the control and regulation of the intermediate heat exchanger 11, the air-conditioning unit also includes: a solenoid valve 13, which is located on the pipeline between the first end of the intermediate heat exchanger 11 and the first four-way valve 2; the switch of the solenoid valve 13 can determine whether to use the intermediate heat exchanger 11; an auxiliary electronic expansion valve 14, which is located on the pipeline between the second end of the intermediate heat exchanger 11 and the first connection point, and the auxiliary electronic expansion valve 14 cooperates with the first electronic expansion valve 4 or the second electronic expansion valve 9 to perform diversion.

[0052] In addition, the first heat exchange system also includes: a first filter 15 and / or a second filter 16; wherein the first filter 15 is located on the pipeline between the first condenser 3 and the first electronic expansion valve 4, and the second filter 16 is located on the pipeline between the first electronic expansion valve 4 and the first evaporator 5; the second heat exchange system also includes: a third filter 17 and / or a fourth filter 18; wherein the third filter 17 is located on the pipeline between the second condenser 8 and the second electronic expansion valve 9, and the fourth filter 18 is located on the pipeline between the second electronic expansion valve 9 and the second evaporator 10.

[0053] like Figure 1 As shown, the air conditioning unit further includes: an indoor fan 19; a first evaporator 5, a second evaporator 10 and the indoor fan 19 are arranged in parallel front and back. In addition, the air conditioning unit further includes a first gas-liquid separator 20 and a second gas-liquid separator 21.

[0054] This air-conditioning unit can operate under various control targets according to different seasons and working conditions. It has the characteristics of avoiding frosting and defrosting without stopping, high operating stability and good user experience.

[0055] Example 2

[0056] In a preferred embodiment 2 of the present invention, a method for controlling an air conditioning unit is provided, which is applied to the air conditioning unit in the above embodiment 1. Specifically, Figure 2 An optional flow chart of the method is shown as follows: Figure 2 As shown, the method includes the following steps S202-S206:

[0057] S202: Detecting the outdoor ambient temperature and setting the operating mode;

[0058] S204: Determine the operation mode of the air conditioning unit according to the outdoor ambient temperature and the set operation mode;

[0059] S206: Control the operation of the air conditioning unit according to the operation mode.

[0060] In the above embodiment, a frost-free, continuous heating multi-system air conditioning unit is provided. In addition to the dual systems, namely the first heat exchange system and the second heat exchange system, the air conditioning unit also includes an intermediate heat exchanger. The first condenser, the second condenser and the intermediate heat exchanger are arranged in parallel front and back, and the intermediate heat exchanger is located at the front or rear side. The intermediate heat exchanger can increase the temperature of the air entering the outdoor evaporator, avoid the evaporation temperature being too high, causing the unit to frost, and thus avoid the problem of the air conditioning unit being shut down due to defrosting, thereby improving the operating stability of the air conditioning unit and the user comfort.

[0061] Among them, the operating modes at least include: conventional cooling mode, high-temperature cooling mode, conventional heating mode, and low-temperature heating mode; the operating mode of the air-conditioning unit is determined according to the outdoor ambient temperature and the set operating mode, including: when the operating mode is set to cooling mode and the outdoor ambient temperature is less than or equal to a first preset temperature, the operating mode of the air-conditioning unit is determined to be a conventional cooling mode; when the operating mode is set to cooling mode and the outdoor ambient temperature is greater than a first preset temperature (for example, 45°C), the operating mode of the air-conditioning unit is determined to be a high-temperature cooling mode; when the operating mode is set to heating mode and the outdoor ambient temperature is greater than a second preset temperature (for example, -10°C), the operating mode of the air-conditioning unit is determined to be a conventional heating mode; when the operating mode is set to heating mode and the outdoor ambient temperature is less than or equal to a second preset temperature, the operating mode of the air-conditioning unit is determined to be a low-temperature heating mode; wherein the first preset temperature is greater than the second preset temperature.

[0062] After determining the operation mode, the operation of the air conditioning unit is controlled according to the operation mode, including:

[0063] When the air-conditioning unit operates in conventional cooling mode, the solenoid valve and the auxiliary electronic expansion valve are controlled to be disconnected, and the first heat exchange system and the second heat exchange system are controlled to operate in cooling mode; when the unit operates in conventional cooling mode, the solenoid valve and the auxiliary electronic expansion valve are closed, and the high-temperature and high-pressure gas discharged from the compressor flows to the outdoor condenser, and after condensation and throttling by the electronic expansion valve, it all enters the indoor evaporator, and finally returns to the compressor to complete the entire refrigeration cycle.

[0064] When the operation mode of the air-conditioning unit is the high-temperature cooling mode, the solenoid valve and the auxiliary electronic expansion valve are controlled to close, and the first heat exchange system and the second heat exchange system are controlled to operate in the cooling mode; when the unit operates in the high-temperature cooling condition, the coil temperature of the first condenser and the coil temperature of the second condenser are detected. When the coil temperature of the first condenser and / or the coil temperature of the second condenser is lower than the preset frosting temperature, the solenoid valve and the auxiliary electronic expansion valve are opened, and the high-temperature and high-pressure gas discharged from the compressor is distributed by the electronic expansion valve and the auxiliary electronic expansion valve, and a part of it flows to the outdoor evaporator (intermediate heat exchanger), and a part of it passes through the indoor evaporator, and finally returns to the compressor to complete the entire refrigeration cycle. At this time, the state change process of the air is: the outdoor fan blows air to the intermediate heat exchanger, and the air is first cooled and cooled through the intermediate heat exchanger, and then enters the outdoor condenser (the first condenser and the second condenser), reducing the control temperature entering the outdoor condenser, thereby reducing the temperature of the outdoor condenser, avoiding excessive condensation temperature, causing high temperature and high pressure protection of the unit.

[0065] When the air-conditioning unit operates in conventional heating mode, the solenoid valve and the auxiliary electronic expansion valve are controlled to be disconnected, and the first heat exchange system and the second heat exchange system are controlled to operate in heating mode; when the unit operates in conventional heating mode, the solenoid valve and the auxiliary electronic expansion valve are closed (the outdoor evaporator is in a closed state at this time), and the high-temperature and high-pressure gas discharged from the compressor flows to the indoor evaporator, and after condensation, it enters the outdoor condenser through the throttling of the electronic expansion valve, and finally returns to the compressor to complete the entire refrigeration cycle.

[0066] When the air conditioning unit is in low-temperature heating mode, the solenoid valve and the auxiliary electronic expansion valve are controlled to close, and the first heat exchange system and the second heat exchange system are controlled to operate in heating mode. When the unit is operating in low-temperature heating mode, the solenoid valve and the auxiliary electronic expansion valve are opened, and part of the high-temperature and high-pressure gas discharged from the compressor flows to the indoor evaporator, and part passes through the outdoor evaporator, and after being distributed by the electronic expansion valve and the auxiliary electronic expansion valve, it flows to the outdoor condenser, and finally returns to the compressor to complete the entire refrigeration cycle. At this time, the state change process of the air is: the outdoor fan blows in the opposite direction of the intermediate heat exchanger, and the air is first heated by the outdoor condenser to increase the temperature of the air entering the outdoor evaporator, so as to avoid the evaporation temperature being too high, causing the unit to frost and low-pressure protection.

[0067] When the operation mode of the air-conditioning unit is the low-temperature heating mode, and after the operation of the air-conditioning unit is controlled according to the operation mode, it also includes: detecting the opening of the auxiliary electronic expansion valve; when the opening of the auxiliary electronic expansion valve reaches the preset maximum opening, detecting the coil temperature of the first condenser and the coil temperature of the second condenser; when the coil temperature of the first condenser is less than the preset frosting temperature, controlling the second heat exchange system to operate in the cooling mode; when the coil temperature of the second condenser is less than the preset frosting temperature, controlling the first heat exchange system to operate in the cooling mode, and controlling the reversal of the outdoor fan. Continuously detecting the coil temperature of the outdoor condenser, if it is lower than the preset frosting temperature and the opening of the auxiliary electronic expansion valve has been opened to the upper limit, judging whether the unit needs to perform defrosting operation, closing the solenoid valve and the auxiliary electronic expansion valve, adjusting the reversal of the system four-way valve (heating to cooling mode), and adjusting the direction of the outdoor fan at the same time. Ensure that one heat exchange system is cooling and defrosting while the other heat exchange system is running for heating, so as to ensure the continuous heating capacity of the air-conditioning unit.

[0068] Another air conditioning unit control method is provided in a preferred embodiment 2 of the present invention. Specifically, Figure 3 An optional flow chart of the method is shown as follows: Figure 3 As shown, the method includes the following steps S301-S315:

[0069] S301: Turn on the machine;

[0070] S302: Detecting the outdoor ambient temperature and setting the operating mode, the unit automatically operates in the following modes; the operating mode of the air-conditioning unit can be determined according to the outdoor ambient temperature and the set operating mode, mainly including the following modes: conventional heating mode, conventional cooling mode, low-temperature heating mode and high-temperature cooling mode;

[0071] S303: conventional heating mode; when the operating mode is set to the heating mode and the outdoor ambient temperature is greater than the second preset temperature, determining that the operating mode of the air-conditioning unit is the conventional heating mode;

[0072] S304: The intermediate heat exchanger is not turned on; the intermediate heat exchanger does not need to be used in the conventional heating mode;

[0073] S305: conventional cooling mode; when the operating mode is set to the cooling mode and the outdoor ambient temperature is less than or equal to the first preset temperature, determining that the operating mode of the air-conditioning unit is the conventional cooling mode;

[0074] S306: The intermediate heat exchanger is not turned on; the intermediate heat exchanger does not need to be used in the conventional cooling mode;

[0075] S307: low-temperature heating mode; when the operating mode is set to the heating mode and the outdoor ambient temperature is less than or equal to the second preset temperature, determining that the operating mode of the air-conditioning unit is the low-temperature heating mode;

[0076] S308: The intermediate heat exchanger is turned on, and the opening of the auxiliary electronic expansion valve is adjusted; in the low-temperature heating mode, the solenoid valve and the auxiliary electronic expansion valve are controlled to be closed, thereby controlling the intermediate heat exchanger to be turned on, and then adjusting the opening of the auxiliary electronic expansion valve to meet the heat exchange requirements, and controlling the first heat exchange system and the second heat exchange system to operate in the heating mode; then, entering step S311;

[0077] S309: high temperature cooling mode; when the operating mode is set to the cooling mode and the outdoor ambient temperature is greater than the first preset temperature, determining that the operating mode of the air-conditioning unit is the high temperature cooling mode;

[0078] S310: The intermediate heat exchanger is turned on, and the opening of the auxiliary electronic expansion valve is adjusted; when the operation mode of the air-conditioning unit is the high-temperature cooling mode, the solenoid valve and the auxiliary electronic expansion valve are controlled to be closed, thereby controlling the intermediate heat exchanger to be turned on, and then adjusting the opening of the auxiliary electronic expansion valve to meet the heat exchange requirements, and controlling the first heat exchange system and the second heat exchange system to operate in the cooling mode;

[0079] S311: When the auxiliary electronic expansion valve is fully opened and the outdoor condenser coil temperature is lower than the preset frosting temperature, the coil temperature of the outdoor condenser is detected, and steps S312 and S314 are entered;

[0080] S312: If the first outdoor condenser coil temperature To3<To3m holds, proceed to step S313;

[0081] S313: Control the outdoor fan to operate normally, and switch the second heat exchange system to cooling mode;

[0082] S314: If the second outdoor condenser coil temperature To4<To4m holds, proceed to step S315;

[0083] S315: Control the outdoor fan to run in reverse, and switch the first heat exchange system to cooling mode; continue to detect the coil temperature of the outdoor condenser. If it is lower than the preset frosting temperature and the auxiliary electronic expansion valve has been opened to the upper limit, determine whether the unit needs to defrost, close the solenoid valve and the auxiliary electronic expansion valve, adjust the system four-way valve to switch (heating to cooling mode), and adjust the direction of the outdoor fan at the same time. Ensure that one heat exchange system is cooling and defrosting while the other heat exchange system is running for heating, to ensure the continuous heating capacity of the air-conditioning unit.

[0084] Example 3

[0085] Based on the air conditioning unit control method provided in the above-mentioned embodiment 2, a storage medium containing computer executable instructions is also provided in a preferred embodiment 3 of the present invention. When the computer executable instructions are executed by a computer processor, they are used to execute the air conditioning unit control method as described above.

[0086] In the above embodiment, a frost-free, continuous heating multi-system air conditioning unit is provided. In addition to the dual systems, namely the first heat exchange system and the second heat exchange system, the air conditioning unit also includes an intermediate heat exchanger. The first condenser, the second condenser and the intermediate heat exchanger are arranged in parallel front and back, and the intermediate heat exchanger is located at the front or rear side. The intermediate heat exchanger can increase the temperature of the air entering the outdoor evaporator, avoid the evaporation temperature being too high, causing the unit to frost, and thus avoid the problem of the air conditioning unit being shut down due to defrosting, thereby improving the operating stability of the air conditioning unit and the user comfort.

[0087] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not invented by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0088] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. An air conditioning unit, characterized in that: include: The first heat exchange system comprises: a first compressor (1), a first four-way valve (2), a first condenser (3), a first electronic expansion valve (4) and a first evaporator (5) which are connected in sequence; The second heat exchange system comprises: a second compressor (6), a second four-way valve (7), a second condenser (8), a second electronic expansion valve (9), and a second evaporator (10) which are connected in sequence; an intermediate heat exchanger (11), a first end of which is connected to the first four-way valve (2), and a second end of which is connected to a first connection point arranged on a pipeline between the first condenser (3) and the first electronic expansion valve (4); Wherein, the first condenser (3), the second condenser (8) and the intermediate heat exchanger (11) are arranged in parallel; an outdoor fan (12) arranged in parallel with the first condenser (3), the second condenser (8) and the intermediate heat exchanger (11); a solenoid valve (13) located on the pipeline between the first end of the intermediate heat exchanger (11) and the first four-way valve (2); an auxiliary electronic expansion valve (14), located on the pipeline between the second end of the intermediate heat exchanger (11) and the first connection point; Wherein, when the set operating mode of the air-conditioning unit is the heating mode and the outdoor ambient temperature is less than or equal to the second preset temperature, the operating mode of the air-conditioning unit is the low-temperature heating mode; in the low-temperature heating mode, the solenoid valve (13) and the auxiliary electronic expansion valve (14) are opened, the first heat exchange system and the second heat exchange system operate in the heating mode, and when the opening degree of the auxiliary electronic expansion valve (14) reaches the preset maximum opening degree, the coil temperature of the second condenser (8) is less than the preset frosting temperature, the first heat exchange system operates in the cooling mode and the outdoor fan (12) is reversed.

2. The air conditioning unit according to claim 1, characterized in that: The first heat exchange system further comprises: a first filter (15) and / or a second filter (16); wherein the first filter (15) is located on the pipeline between the first condenser (3) and the first electronic expansion valve (4), and the second filter (16) is located on the pipeline between the first electronic expansion valve (4) and the first evaporator (5); The second heat exchange system further comprises: a third filter (17) and / or a fourth filter (18); wherein the third filter (17) is located on the pipeline between the second condenser (8) and the second electronic expansion valve (9), and the fourth filter (18) is located on the pipeline between the second electronic expansion valve (9) and the second evaporator (10).

3. The air conditioning unit according to claim 1, characterized in that: Also includes: Indoor fan (19); the first evaporator (5), the second evaporator (10) and the indoor fan (19) are arranged in parallel front and back.

4. The air conditioning unit according to claim 1, characterized in that: The outdoor fan (12) is a steerable fan.

5. A method for controlling an air conditioning unit, applied to the air conditioning unit according to any one of claims 1 to 4, characterized in that: The method comprises: Detect outdoor ambient temperature and set operating mode; Determining the operating mode of the air conditioning unit according to the outdoor ambient temperature and the set operating mode; The operation of the air conditioning unit is controlled according to the operation mode.

6. The method according to claim 5, characterized in that The set operation mode includes at least: cooling mode and heating mode; the operation mode includes at least: conventional cooling mode, high temperature cooling mode, conventional heating mode, and low temperature heating mode; the operation mode of the air-conditioning unit is determined according to the outdoor ambient temperature and the set operation mode, including: When the set operation mode is the cooling mode and the outdoor ambient temperature is less than or equal to a first preset temperature, determining that the operation mode of the air-conditioning unit is a conventional cooling mode; When the set operation mode is the cooling mode and the outdoor ambient temperature is greater than the first preset temperature, determining that the operation mode of the air-conditioning unit is the high-temperature cooling mode; When the set operation mode is the heating mode and the outdoor ambient temperature is greater than a second preset temperature, determining that the operation mode of the air-conditioning unit is a conventional heating mode; When the set operation mode is the heating mode and the outdoor ambient temperature is less than or equal to the second preset temperature, the operation mode of the air-conditioning unit is determined to be the low-temperature heating mode; wherein the first preset temperature is greater than the second preset temperature.

7. The method according to claim 6, characterized in that Controlling the operation of the air conditioning unit according to the operation mode includes: When the operation mode of the air-conditioning unit is a conventional cooling mode, the solenoid valve and the auxiliary electronic expansion valve are controlled to be disconnected, and the first heat exchange system and the second heat exchange system are controlled to operate in a cooling mode; When the operation mode of the air-conditioning unit is a high-temperature cooling mode, the solenoid valve and the auxiliary electronic expansion valve are controlled to open, and the first heat exchange system and the second heat exchange system are controlled to operate in a cooling mode; When the operation mode of the air-conditioning unit is a conventional heating mode, controlling the solenoid valve and the auxiliary electronic expansion valve to open, and controlling the first heat exchange system and the second heat exchange system to operate in a heating mode; When the operation mode of the air-conditioning unit is the low-temperature heating mode, the solenoid valve and the auxiliary electronic expansion valve are controlled to open, and the first heat exchange system and the second heat exchange system are controlled to operate in the heating mode.

8. The method according to claim 7, characterized in that When the operation mode of the air-conditioning unit is a low-temperature heating mode, and after controlling the operation of the air-conditioning unit according to the operation mode, the method further includes: detecting the opening degree of the auxiliary electronic expansion valve; When the opening of the auxiliary electronic expansion valve reaches a preset maximum opening, detecting the coil temperature of the first condenser and the coil temperature of the second condenser; When the coil temperature of the first condenser is lower than a preset frosting temperature, controlling the second heat exchange system to operate in a cooling mode; When the coil temperature of the second condenser is lower than the preset frosting temperature, the first heat exchange system is controlled to operate in a cooling mode, and the outdoor fan is controlled to reverse.

9. A storage medium containing computer executable instructions, characterized in that: The computer executable instructions are used to execute the air conditioning unit control method according to any one of claims 5 to 8 when executed by a computer processor.

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