Air conditioning system and control method thereof

Abstract

The invention relates to the technical field of air conditioners, particularly provides an air conditioning system and a control method thereof, and aims to solve the problems of debugging time increase and energy waste caused by the fact that an existing heat pump air conditioner cannot accurately judge whether a refrigerant moves forwards or is preheated after being electrified every time. In order to achieve the purpose, the air conditioning system comprises a compressor, a first heat exchanger and a second heat exchanger, the second heat exchanger is used for refrigerating or heating, and the control method comprises the following steps that according to the temperature of the environment where the first heat exchanger is located, the current temperature of the second heat exchanger and the operation mode of the air conditioning system, the second heat exchanger is used for refrigerating or heating; and whether the lubricating oil is preheated or not and / or the liquid refrigerant in the compressor is discharged is controlled. Whether refrigerant migration occurs or not can be accurately judged according to the environment temperature, the current temperature and the operation mode, preheating is conducted or the liquid refrigerant is discharged when migration occurs, and it can be guaranteed that an air conditioner system is not damaged.

Description

Technical Field

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

[0002] With the development of society and the economy, air conditioning systems are being used in all aspects of life. Heat pump air conditioners, which can provide water, cooling, and heating, have become the preferred choice for many users. When the air-cooled module of a heat pump air conditioner is first installed or has been stored for a long time, the refrigerant will migrate to areas with lower temperatures. To prevent the compressor fluid from compressing, the compressor must be preheated. Fixed-frequency compressors generally do not have oil temperature sensors, so oil temperature cannot be used to determine the temperature.

[0003] Currently, there are two ways to determine the oil temperature preheating of fixed-frequency heat pump units. One is to preheat before the first operation after installation, and no preheating is performed subsequently. Long-term power outage and storage will cause refrigerant migration, which may cause liquid compression; the other is to preheat every time the power is turned on, no matter how long it has been since the last power outage and no matter what the ambient water temperature is. In this way, it is impossible to determine whether the compressor really needs to be heated, and the heating time is longer, which increases the debugging time of the air conditioner and wastes time.

[0004] Therefore, there is an urgent need for an air-conditioning system and a control method thereof to solve the above technical problems. Summary of the Invention

[0005] The present invention aims to solve the above technical problems, that is, to solve the problem that the existing heat pump air conditioner cannot accurately determine whether the refrigerant has moved forward or preheats every time it is powered on, resulting in increased debugging time and energy waste.

[0006] In a first aspect, the present invention provides a control method for an air-conditioning system, the air-conditioning system comprising a compressor, a first heat exchanger, and a second heat exchanger, the second heat exchanger being used for cooling or heating, the control method comprising the following steps:

[0007] Whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor is controlled according to the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system.

[0008] In a specific embodiment of the control method of the air-conditioning system, “controlling whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system” includes:

[0009] In the heating mode, if the ambient temperature is not lower than the current temperature, there is no need to preheat the lubricating oil and discharge the liquid refrigerant in the compressor.

[0010] In a specific embodiment of the control method of the air-conditioning system, “controlling whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system” further includes:

[0011] In heating mode, if the ambient temperature is lower than the current temperature, whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor is determined based on the ambient temperature, the current temperature and the shutdown time of the air conditioning system.

[0012] In a specific embodiment of the control method of the air-conditioning system, “determining whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature, the current temperature, and the shutdown time of the air-conditioning system” includes:

[0013] determining a first target preheating time of the lubricating oil according to the ambient temperature, the current temperature, and the shutdown time;

[0014] Whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor is determined based on the first target preheating time.

[0015] In a specific embodiment of the control method of the air conditioning system, “determining the first target preheating time of the lubricating oil according to the ambient temperature, the current temperature, and the shutdown time” includes:

[0016] The first target preheating time=a1×(current temperature−ambient temperature)+b1×off time+c1; wherein a1, b1, and c1 are all constants.

[0017] In a specific embodiment of the control method of the air conditioning system, “determining whether to preheat the lubricating oil according to the first target preheating time” includes:

[0018] If the first target preheating time is not less than the first preset time, preheating is performed according to the first target preheating time; and / or

[0019] If the first target preheating time is less than the first preset time, there is no need to preheat the lubricating oil.

[0020] In a specific embodiment of the control method of the air-conditioning system, “determining whether to discharge the liquid refrigerant in the compressor according to the first target preheating time” includes:

[0021] If the first target preheating time is less than the first preset time, there is no need to discharge the liquid refrigerant in the compressor; and / or

[0022] If the first target preheating time is not less than the first preset time, discharging the liquid refrigerant in the compressor;

[0023] In a specific embodiment of the control method of the air-conditioning system, “discharging the liquid refrigerant in the compressor” includes:

[0024] The number of inching times of the compressor is determined according to the first target preheating time.

[0025] In a specific embodiment of the control method of the air-conditioning system, “controlling whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system” includes:

[0026] In the cooling mode, if the ambient temperature is not higher than the current temperature, there is no need to preheat the lubricating oil and discharge the liquid refrigerant in the compressor.

[0027] In a specific embodiment of the control method of the air-conditioning system, “controlling whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system” further includes:

[0028] In cooling mode, if the ambient temperature is higher than the current temperature, whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor is determined based on the ambient temperature, the current temperature and the shutdown time of the air conditioning system.

[0029] In a specific embodiment of the control method of the air-conditioning system, “determining whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature, the current temperature, and the shutdown time of the air-conditioning system” includes:

[0030] determining a second target preheating time of the lubricating oil according to the ambient temperature, the current temperature, and the shutdown time;

[0031] Whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor is determined according to the second target preheating time.

[0032] In a specific embodiment of the control method of the air conditioning system, “determining the second target preheating time of the lubricating oil according to the ambient temperature, the current temperature, and the shutdown time” includes:

[0033] The second target preheating time=a2×(ambient temperature−current temperature)+b2×off time+c2; wherein a2, b2, and c2 are all constants.

[0034] In a specific embodiment of the control method of the air-conditioning system, “determining whether to preheat the lubricating oil according to the second target preheating time” includes:

[0035] If the second target preheating time is not less than the second preset time, preheating is performed according to the second target preheating time; and / or

[0036] If the second target preheating time is less than the second preset time, there is no need to preheat the lubricating oil.

[0037] In a specific embodiment of the control method of the air-conditioning system, “determining whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor according to the second target preheating time” includes:

[0038] If the second target preheating time is not less than the second preset time, the liquid refrigerant in the compressor is discharged; and / or

[0039] If the second target preheating time is less than the second preset time, there is no need to discharge the liquid refrigerant in the compressor.

[0040] In a specific embodiment of the control method of the air-conditioning system, “discharging the liquid refrigerant in the compressor” includes:

[0041] The number of inching times of the compressor is determined according to the second target preheating time.

[0042] In a second aspect, the present invention provides an air-conditioning system, which includes a control module configured to execute the above air-conditioning system control method.

[0043] When adopting the above technical solution, the air conditioning system of the present invention includes a compressor, a first heat exchanger, and a second heat exchanger, wherein the second heat exchanger is used for cooling or heating. The control method includes the following steps: controlling whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air conditioning system. Based on the ambient temperature, current temperature, and operating mode, it is possible to accurately determine whether refrigerant migration has occurred. If migration occurs, preheating or discharging the liquid refrigerant can ensure that the air conditioning system is not damaged.

[0044] In addition, the shutdown duration is also taken into account when accurately determining whether migration has occurred, which can more accurately determine whether migration has occurred and the amount of migration.

[0045] Furthermore, the preheating duration is determined based on the ambient temperature, current temperature, and shutdown duration—that is, the migration amount. This ensures the preheating duration is just right, avoiding the presence of liquid refrigerant and ensuring energy is not wasted. The number of inching cycles, and therefore the amount of refrigerant discharged, is determined based on the target preheating duration, avoiding the presence of liquid refrigerant and ensuring energy is not wasted. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0047] Figure 1 This is a flowchart of the detailed steps of "determining whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature, the current temperature, and the shutdown time of the air-conditioning system" provided in the first embodiment of the present invention;

[0048] Figure 2 It is a flowchart of the detailed steps of "determining whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature, the current temperature and the shutdown time of the air-conditioning system" provided in the second embodiment of the present invention. DETAILED DESCRIPTION

[0049] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0050] It should be noted that in the description of the present invention, terms such as "upper," "lower," "left," "right," "inner," and "outer" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. These terms are used solely for ease of description and are not intended to indicate or imply that the device or component described must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "installed," "disposed," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0052] When the air-cooled module unit of a heat pump air conditioner is installed for the first time or has been stored for a long time, the refrigerant will migrate to places with lower temperatures. To prevent compressor liquid compression, the compressor needs to be preheated; fixed-frequency compressors generally do not have oil temperature sensors and cannot be judged by oil temperature.

[0053] Currently, there are two ways to determine the oil temperature preheating of fixed-frequency heat pump units. One is to preheat before the first operation after installation, and no preheating is performed subsequently. Long-term power outage and storage will cause refrigerant migration, which may cause liquid compression; the other is to preheat every time the power is turned on, no matter how long it has been since the last power outage and no matter what the ambient water temperature is. In this way, it is impossible to determine whether the compressor really needs to be heated, and the heating time is longer, which increases the debugging time of the air conditioner and wastes time.

[0054] In order to solve the above-mentioned technical problems, the present invention discloses an air-conditioning system, which includes a compressor, a four-way valve, a first heat exchanger, a second heat exchanger, and a solenoid valve. The suction side of the compressor is connected to the first interface of the four-way valve, and the exhaust side is connected to the second interface of the four-way valve; the third interface of the four-way valve, the first heat exchanger, the solenoid valve, the second heat exchanger, and the fourth interface of the four-way valve are connected in sequence. The first heat exchanger is an air-cooled heat exchanger, that is, a fan is provided on one side of the first heat exchanger, and the first heat exchanger exchanges heat with the air. The second heat exchanger is used for cooling or heating, and can specifically exchange heat directly with the air or with a liquid such as water. The air-conditioning system in this embodiment is specifically a heat pump air-conditioning system, which also includes a water pump and water-using equipment. The second heat exchanger is used for exchanging heat with water, and the second heat exchanger is provided with a first flow channel and a second flow channel, wherein the first flow channel is connected to the solenoid valve and the fourth interface of the four-way valve. The second flow channel, the water pump, and the water-using equipment are connected in sequence, and the water pump drives water to flow through the second flow channel and the water-using equipment. The water in the second flow channel exchanges heat with the refrigerant in the first flow channel to be heated or cooled. The second heat exchanger is specifically a plate heat exchanger.

[0055] In heating mode, the second port of the four-way valve is connected to the fourth port of the four-way valve, and the first port of the four-way valve is connected to the third port. The high-temperature, high-pressure gaseous refrigerant flowing out of the compressor flows to the second heat exchanger, where it releases heat to heat the water in the second flow channel. After heat exchange, the refrigerant becomes liquid refrigerant. After passing through the solenoid valve, it flows to the first heat exchanger for heat exchange. The refrigerant absorbs heat and becomes gaseous refrigerant, which then flows back to the compressor through the four-way valve.

[0056] In cooling mode, the second port of the four-way valve is connected to the third port of the four-way valve, and the first port of the four-way valve is connected to the fourth port. The high-temperature, high-pressure gaseous refrigerant flowing out of the compressor flows to the first heat exchanger, where it exchanges heat with the air. After the heat exchange, the refrigerant becomes liquid refrigerant. After passing through the solenoid valve, it flows to the second heat exchanger for heat exchange, where it absorbs heat to cool the water in the second flow channel. After the heat exchange, the refrigerant becomes gaseous refrigerant and flows back to the compressor through the four-way valve again.

[0057] A temperature sensor is installed on the outside of the first heat exchanger to detect the ambient temperature of the first heat exchanger. A temperature sensor is installed at the water outlet of the second flow channel to detect the outlet water temperature of the second heat exchanger, that is, the current temperature of the second heat exchanger. The air conditioning system also includes a wired controller and a control module. The wired controller sends a signal to the control module at set intervals. The number of signal transmissions determines the air conditioning system's shutdown duration, which is the duration of the power outage since the last shutdown.

[0058] This embodiment discloses a control method for an air conditioning system, which includes the following steps:

[0059] S0. Obtain the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system.

[0060] S1. Control whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air conditioning system. In the present invention, preheating the lubricating oil or discharging the liquid refrigerant in the compressor is selected.

[0061] The control method will be described in detail below with two embodiments.

[0062] Example 1

[0063] “Controlling whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system” specifically includes:

[0064] In heating mode, if the ambient temperature is not lower than the current temperature, there is no need to preheat the lubricating oil or discharge the liquid refrigerant in the compressor.

[0065] When the ambient temperature is not lower than the current temperature, that is, the current temperature is low, the refrigerant will migrate to the lower temperature area, that is, the refrigerant will migrate to the second heat exchanger side. Since the refrigerant flowing out of the compressor in heating mode first flows to the second heat exchanger, the refrigerant on the second heat exchanger side will pass through the solenoid valve and heat exchange with the first heat exchanger before returning to the compressor. The liquid refrigerant accumulated in the second heat exchanger can only flow back to the compressor after heat exchange with the first heat exchanger. This can ensure that the refrigerant flowing into the compressor is gaseous refrigerant, avoiding damage to the compressor. Therefore, there is no need to preheat the lubricating oil or discharge the liquid refrigerant in the compressor.

[0066] “Controlling whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system” specifically includes:

[0067] In heating mode, if the ambient temperature is lower than the current temperature, the system determines whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature, the current temperature, and the shutdown time of the air conditioning system.

[0068] When the ambient temperature is lower than the current temperature, that is, the ambient temperature is low, the refrigerant will migrate to a place with a lower temperature, that is, the refrigerant will migrate to the first heat exchanger and the compressor side. Since in heating mode, the refrigerant flowing out of the compressor first flows to the second heat exchanger, the refrigerant on the second heat exchanger side will flow back to the compressor after passing through the solenoid valve and the first heat exchanger for heat exchange. The liquid refrigerant accumulated in the first heat exchanger can flow directly to the compressor. Therefore, if there is a lot of liquid refrigerant accumulated, it will damage the compressor if it flows directly to the compressor. Therefore, if the shutdown time is long, it is necessary to preheat and / or discharge the liquid refrigerant in the compressor. Discharging the refrigerant in the compressor refers to discharging the refrigerant accumulated in the first heat exchanger and the compression part to the exhaust side of the compressor.

[0069] like Figure 1 As shown, “determining whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature, the current temperature, and the shutdown time of the air conditioning system” includes:

[0070] S11. Determine a first target preheating time of the lubricating oil based on the ambient temperature, the current temperature, and the shutdown time;

[0071] S12. Determine whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the first target preheating time.

[0072] Among them, step S11, "determining a first target preheating time of the lubricating oil according to the ambient temperature, the current temperature and the shutdown time" specifically includes:

[0073] First target preheating time = a1 × (current temperature - ambient temperature) + b1 × shutdown time + c1, where a1, b1, and c1 are all constants.

[0074] The first target preheating time and the current temperature and the shutdown time of the ambient thermometer can be specifically obtained based on data from actual machine experiments, and then regression analysis is performed to obtain the values of a1, b1 and c1; or a simulation experiment can be performed based on the data model, and regression analysis can be performed based on the simulation experiment data to obtain the values of a1, b1 and c1.

[0075] Wherein, step S12, "determining whether to preheat the lubricating oil according to the first target preheating time" includes:

[0076] If the first target preheating time is not less than the first preset time, preheating is performed according to the first target preheating time; the first preset time is a critical value, which can be obtained by obtaining data based on actual machine experiments and then analyzing and obtaining it; it can also be obtained by conducting simulation experiments based on the data model and analyzing and obtaining it based on the simulation experiment data. When the first target preheating time is greater than the critical value, it means that a large amount of liquid refrigerant has accumulated in the first heat exchanger and the compressor. Preheating the lubricating oil can ensure that the refrigerant flowing into the compressor is a gaseous refrigerant, ensuring that the compressor is not damaged. Furthermore, the preheating time is determined based on the current temperature and the length of time the ambient thermometer is turned off, which can make it more compatible with the current state of the air-conditioning system, ensuring that the preheating time is neither too long nor too short, which saves energy and ensures that the air conditioner is not damaged.

[0077] If the first target preheating time is less than the first preset time, there is no need to preheat the lubricating oil. If the first target preheating time has not reached the critical value, directly starting the compressor will have little impact on the compressor and will almost never damage the compressor. Therefore, preheating is not required to avoid energy waste. Even if preheating is performed according to the calculated first target preheating time, the change in the refrigerant flowing into the compressor is minimal, so preheating is not required.

[0078] “Determining whether to discharge liquid refrigerant in the compressor based on a first target preheating time” includes:

[0079] If the first target preheating time is less than the first preset time, there is no need to discharge the liquid refrigerant in the compressor;

[0080] If the first target preheating time is not less than the first preset time, discharging the liquid refrigerant in the compressor;

[0081] Among them, "liquid refrigerant discharged from the compressor" includes:

[0082] The number of compressor inching times is determined based on the first target preheating time. If the first target preset time is less than the third preset time, the compressor is inched d1 times; wherein the third preset time is greater than the first preset time, in this example, the third preset time is preferably 2 hours, and in other embodiments, it can also be 1.5 or 2.5 hours, and the value of d1 is 2. If the first target preset time is less than the fourth preset time, the compressor is inched d2 times; wherein the fourth preset time is greater than the third preset time, in this example, the fourth preset time is preferably 10 hours, and in other embodiments, it can also be 9 or 11 hours, and the value of d2 is 3. If the first target preset time is not less than the fourth preset time, the compressor is inched d3 times; the value of d2 is 5. A inching switch is provided in the wired controller, and the inching is specifically achieved by the inching switch.

[0083] Regarding the number of inching times and the first target preset duration, it should be noted that although the values are taken according to a range in this embodiment, this is not a limitation of the present invention. Without departing from the principles of the present invention, in other embodiments, a linear functional relationship between the first target preset duration and the number of inching times may be established, but the number of inching times may be rounded to an integer or directly rounded to an integer, and all values less than 2 are rounded to 2. This does not deviate from the basic principles of the present invention and falls within the scope of protection of the present invention.

[0084] One click specifically includes: turning on the device for the fourth preset time, then turning off the device for the fifth preset time, and then performing other operations. The fifth preset time is longer than the fourth preset time.

[0085] The multiple inching operations specifically include: turning on the device for the fourth preset time, then turning off the device for the fifth preset time; then turning on the device again for the fourth preset time, and then turning off the device for the fifth preset time. After the device has been turned on and off multiple times, other operations can be performed.

[0086] Regarding preheating and discharging the liquid refrigerant in the compressor, it should be noted that when there is no rush to start the machine, that is, in normal operating mode, especially when the machine is scheduled to start, the preheating method is used; if a quick start is required, the liquid refrigerant in the compressor is discharged. The customer has an allowed waiting time (in the reservation mode, the reservation time is the allowed waiting time). When the first target preheating time is longer than the allowed waiting time and preheating is required, the liquid refrigerant in the compressor is discharged to avoid liquid compression in the compressor and achieve a quick start. When the first target preheating time is not longer than the allowed waiting time and preheating is required, the lubricating oil is preheated to heat the liquid refrigerant in the compressor into a gaseous refrigerant to avoid liquid compression in the compressor and ensure that the compressor is not damaged.

[0087] Example 2

[0088] “Controlling whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system” also includes:

[0089] In cooling mode, if the ambient temperature is not higher than the current temperature, there is no need to preheat the lubricating oil and discharge the liquid refrigerant in the compressor.

[0090] When the ambient temperature is not higher than the current temperature, that is, the ambient temperature is low, the refrigerant will migrate to the lower temperature area, that is, the refrigerant will migrate to the first heat exchanger side. In cooling mode, the refrigerant flowing out of the compressor first flows to the first heat exchanger. The refrigerant on the first heat exchanger side will flow to the second heat exchanger through the solenoid valve. The refrigerant absorbs heat in the second heat exchanger and becomes gaseous refrigerant. The refrigerant flowing out of the second heat exchanger flows directly back to the compressor, which can ensure that the refrigerant flowing into the compressor is gaseous refrigerant, avoiding damage to the compressor. Therefore, there is no need to preheat the lubricating oil or discharge the liquid refrigerant in the compressor.

[0091] “Controlling whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system” also includes:

[0092] In cooling mode, if the ambient temperature is higher than the current temperature, the system determines whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature, the current temperature, and the shutdown time of the air conditioning system.

[0093] When the ambient temperature is higher than the current temperature, that is, the current temperature is low, the refrigerant will migrate to a place with a lower temperature, that is, the refrigerant will migrate to the second heat exchanger side. In the cooling mode, the refrigerant flowing out of the compressor first flows to the first heat exchanger. The refrigerant on the first heat exchanger side will flow back to the compressor after passing through the solenoid valve and the second heat exchanger for heat exchange. The liquid refrigerant accumulated in the second heat exchanger can flow directly to the compressor. Therefore, if there is a lot of liquid refrigerant accumulated, it will damage the compressor if it flows directly to the compressor. Therefore, if the shutdown time is long, it is necessary to preheat and / or discharge the liquid refrigerant in the compressor. Discharging the refrigerant in the compressor refers to discharging the refrigerant accumulated in the second heat exchanger and the compression part to the exhaust side of the compressor.

[0094] like Figure 2 As shown, “determining whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature, the current temperature, and the shutdown time of the air conditioning system” includes:

[0095] S21. Determine a second target preheating time of the lubricating oil based on the ambient temperature, the current temperature, and the shutdown time.

[0096] S22. Determine whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the second target preheating time.

[0097] Specifically, step S21, "determining a second target preheating time of the lubricating oil based on the ambient temperature, the current temperature, and the shutdown time" includes:

[0098] Second target preheating time = a2 × (ambient temperature - current temperature) + b2 × shutdown time + c2, where a2, b2, and c2 are all constants.

[0099] The second target preheating time and the current temperature and the ambient thermometer shutdown time can be obtained by obtaining data based on actual machine experiments and then performing regression analysis to obtain the values of a2, b2 and c2; or a simulation experiment can be performed based on the data model, and regression analysis can be performed based on the simulation experiment data to obtain the values of a2, b2 and c2.

[0100] Wherein, step S22, "determining whether to preheat the lubricating oil according to the second target preheating time" includes:

[0101] If the second target preheating time is not less than the second preset time, preheating is performed according to the second target preheating time;

[0102] The second preset time is a critical value, which can be obtained by obtaining data based on actual machine experiments and then analyzing it; it can also be obtained by conducting simulation experiments based on the data model and analyzing it based on the simulation experiment data. When the second target preheating time is greater than the critical value, it means that a large amount of liquid refrigerant has accumulated in the second heat exchanger. Preheating the lubricating oil can ensure that the refrigerant flowing into the compressor is a gaseous refrigerant, ensuring that the compressor is not damaged. Furthermore, the preheating time is determined based on the current temperature and the length of time the ambient thermometer is closed, which can make it more compatible with the current state of the air-conditioning system, ensuring that the preheating time is neither too long nor too short, which saves energy and ensures that the air conditioner will not be damaged.

[0103] If the second target preheating time is less than the second preset time, there is no need to preheat the lubricating oil. If the second target preheating time has not reached the critical value, directly starting the compressor will have little impact on the compressor and will almost never damage the compressor. Therefore, preheating is not required, avoiding energy waste. Even if preheating is performed according to the calculated second target preheating time, the change in the refrigerant flowing into the compressor is minimal, so preheating is not necessary.

[0104] “Determining whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the second target preheating time” includes:

[0105] If the second target preheating time is not less than the second preset time, discharging the liquid refrigerant in the compressor;

[0106] If the second target preheating time is less than the second preset time, there is no need to discharge the liquid refrigerant in the compressor.

[0107] "Liquid refrigerant discharged from the compressor" includes:

[0108] The number of inching times of the compressor is determined according to the second target preheating time.

[0109] If the second target preset duration is less than the third preset duration, the inching is performed d1 times; the third preset duration is greater than the second preset duration, preferably 2 hours in this example, but may be 1.5 or 2.5 hours in other embodiments, and the value of d1 is 2. If the second target preset duration is less than the fourth preset duration, the inching is performed d2 times; the fourth preset duration is greater than the third preset duration, preferably 10 hours in this example, but may be 9 or 11 hours in other embodiments, and the value of d2 is 3. If the second target preset duration is not less than the fourth preset duration, the inching is performed d3 times; the value of d2 is 5.

[0110] Regarding the number of inching times and the second target preset duration, it should be noted that although the values are taken according to a range in this embodiment, this is not a limitation of the present invention. Without departing from the principles of the present invention, in other embodiments, a linear functional relationship between the second target preset duration and the number of inching times may be established, but the number of inching times may be rounded to an integer or directly rounded to an integer, and all values less than 2 are rounded to 2. This does not deviate from the basic principles of the present invention and falls within the scope of protection of the present invention.

[0111] Regarding preheating and discharging the liquid refrigerant in the compressor, it should be noted that when there is no rush to start the machine, that is, in normal operating mode, especially when the machine is scheduled to start, the preheating method is used; if a quick start is required, the liquid refrigerant in the compressor is discharged. The customer has an allowed waiting time (in the reservation mode, the reservation time is the allowed waiting time). When the second target preheating time is longer than the allowed waiting time and preheating is required, the liquid refrigerant in the compressor is discharged to avoid liquid compression in the compressor and achieve a quick start. When the second target preheating time is not longer than the allowed waiting time and preheating is required, the lubricating oil is preheated to heat the liquid refrigerant in the compressor into a gaseous refrigerant to avoid liquid compression in the compressor and ensure that the compressor is not damaged.

[0112] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A control method for an air conditioning system, wherein the air conditioning system comprises a compressor, a first heat exchanger, and a second heat exchanger, wherein the second heat exchanger is used for cooling or heating, wherein: The control method comprises the following steps: Whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor is controlled according to the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system.

2. The control method of the air conditioning system according to claim 1, characterized in that: “Controlling whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system” includes: In the heating mode, if the ambient temperature is not lower than the current temperature, there is no need to preheat the lubricating oil and discharge the liquid refrigerant in the compressor.

3. The control method of the air conditioning system according to claim 2, characterized in that: “Controlling whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system” also includes: In heating mode, if the ambient temperature is lower than the current temperature, whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor is determined based on the ambient temperature, the current temperature and the shutdown time of the air conditioning system.

4. The control method of the air conditioning system according to claim 3, characterized in that: “Determining whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature, the current temperature, and the shutdown duration of the air conditioning system” includes: determining a first target preheating time of the lubricating oil according to the ambient temperature, the current temperature, and the shutdown time; determining whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor according to the first target preheating time; Preferably, “determining a first target preheating time of the lubricating oil according to the ambient temperature, the current temperature, and the shutdown time” includes: The first target preheating time=a1×(current temperature−ambient temperature)+b1×off time+c1; wherein a1, b1, and c1 are all constants.

5. The control method of the air conditioning system according to claim 3, characterized in that: “Determining whether to preheat the lubricating oil according to the first target preheating time” includes: If the first target preheating time is not less than the first preset time, preheating is performed according to the first target preheating time; and / or If the first target preheating time is less than the first preset time, there is no need to preheat the lubricating oil; and / or “Determining whether to discharge the liquid refrigerant in the compressor based on the first target preheating time” includes: If the first target preheating time is less than the first preset time, there is no need to discharge the liquid refrigerant in the compressor; and / or If the first target preheating time is not less than the first preset time, discharging the liquid refrigerant in the compressor; Preferably, “discharging the liquid refrigerant in the compressor” includes: The number of inching times of the compressor is determined according to the first target preheating time.

6. The control method of the air conditioning system according to claim 1, characterized in that: “Controlling whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system” includes: In the cooling mode, if the ambient temperature is not higher than the current temperature, there is no need to preheat the lubricating oil and discharge the liquid refrigerant in the compressor.

7. The control method of the air conditioning system according to claim 6, characterized in that: “Controlling whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature of the first heat exchanger, the current temperature of the second heat exchanger, and the operating mode of the air-conditioning system” also includes: In cooling mode, if the ambient temperature is higher than the current temperature, whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor is determined based on the ambient temperature, the current temperature and the shutdown time of the air conditioning system.

8. The control method of the air conditioning system according to claim 6, characterized in that: “Determining whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the ambient temperature, the current temperature, and the shutdown duration of the air conditioning system” includes: determining a second target preheating time of the lubricating oil according to the ambient temperature, the current temperature, and the shutdown time; determining whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor according to the second target preheating time; Preferably, “determining the second target preheating time of the lubricating oil according to the ambient temperature, the current temperature and the shutdown time” includes: The second target preheating time=a2×(ambient temperature−current temperature)+b2×off time+c2; wherein a2, b2, and c2 are all constants.

9. The control method of the air conditioning system according to any one of claims 6 to 8, characterized in that: “Determining whether to preheat the lubricating oil according to the second target preheating time” includes: If the second target preheating time is not less than the second preset time, preheating is performed according to the second target preheating time; and / or If the second target preheating time is less than the second preset time, there is no need to preheat the lubricating oil; and / or “Determining whether to preheat the lubricating oil and / or discharge the liquid refrigerant in the compressor based on the second target preheating time” includes: If the second target preheating time is not less than the second preset time, the liquid refrigerant in the compressor is discharged; and / or If the second target preheating time is less than the second preset time, there is no need to discharge the liquid refrigerant in the compressor; Preferably, “discharging the liquid refrigerant in the compressor” includes: The number of inching times of the compressor is determined according to the second target preheating time.

10. An air conditioning system, characterized in that: The air conditioning system comprises a control module configured to execute the air conditioning system control method according to any one of claims 1 to 9.

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