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 compressor, a condenser, a throttling device and an evaporator connected in sequence; a main refrigerant branch, one end of which is connected to the refrigerant outlet of the condenser, and the other end is connected to the throttling device, for passing the refrigerant at the refrigerant outlet of the condenser into the throttling device; a subcooling refrigerant branch, which is arranged in parallel with the main refrigerant branch, one end of which is connected to the refrigerant outlet of the condenser, and the other end of which is connected to the throttling device, and a subcooling device is arranged on the subcooling refrigerant branch, for passing the refrigerant flowing through the cold refrigerant branch into the throttling device after being supercooled; a control valve, for controlling the on-off of the main refrigerant branch and the subcooling refrigerant branch according to the subcooling degree of the air conditioning unit. The present invention solves the problem of insufficient subcooling degree in the refrigeration system in the prior art, improves the refrigeration effect and refrigeration efficiency of the air conditioning unit, and ensures the reliable operation of the air conditioning unit.

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] With the expansion of the refrigeration industry in recent years, air conditioning units for refrigeration and freezing are developing rapidly. However, air conditioning units for refrigeration and freezing are different from household air conditioners. They run for a long time without stopping, so they consume a lot of electricity. In addition, compared with household air conditioners, air conditioning units for refrigeration and freezing have higher requirements for energy efficiency and reliability.

[0003] However, in the actual installation and operation process, air-conditioning units for refrigeration and freezing often have a low degree of supercooling in the refrigeration system due to various factors such as excessively high ambient temperature and insufficient amount of refrigerant, resulting in reduced cooling capacity, decreased refrigeration efficiency, and poor refrigeration effect. As a result, the power consumption of the refrigeration system increases, energy efficiency decreases, and compressor losses increase, reducing the reliability and service life of the compressor and the overall unit operation.

[0004] With regard to the problem of insufficient supercooling in the refrigeration system in the related art, 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 of insufficient supercooling in the refrigeration system in the prior art.

[0006] In order to solve the above technical problems, according to one aspect of an embodiment of the present invention, an air-conditioning unit is provided, comprising: a compressor, a condenser, a throttling device and an evaporator connected in sequence; a main refrigerant branch, one end of which is connected to the refrigerant outlet of the condenser, and the other end is connected to the throttling device, and is used to pass the refrigerant at the refrigerant outlet of the condenser into the throttling device; a subcooling refrigerant branch, which is arranged in parallel with the main refrigerant branch, one end of which is connected to the refrigerant outlet of the condenser, and the other end is connected to the throttling device, and the subcooling refrigerant branch A subcooling device is provided for subcooling the refrigerant flowing through the subcooling refrigerant branch and then passing it into the throttling device; a control valve is used to control the on-off of the main refrigerant branch and the subcooling refrigerant branch according to the subcooling degree of the air-conditioning unit; wherein, when subcooling is not required, the main refrigerant branch is controlled to be connected; when subcooling is required, the subcooling refrigerant branch is controlled to be connected, and the operating parameters and environmental parameters of the air-conditioning unit are obtained, and the operation of the subcooling refrigerant branch is controlled according to the operating parameters of the air-conditioning unit and the environmental parameters.

[0007] Furthermore, the control valve includes: a first control valve, located on the main refrigerant branch, used to control the on-off of the main refrigerant branch; a second control valve, located on the subcooling refrigerant branch, used to control the on-off of the subcooling refrigerant branch.

[0008] Furthermore, the control valve includes: a three-way valve, a first end of which is connected to the refrigerant outlet of the condenser, a second end of which is connected to the inlet of the main refrigerant branch, and a third end of which is connected to the inlet of the subcooling refrigerant branch, for controlling the on-off of the main refrigerant branch and the subcooling refrigerant branch.

[0009] Furthermore, the subcooling device includes: a subcooling medium for providing cooling; a heat exchanger, through which the subcooling medium exchanges heat with the refrigerant on the subcooling refrigerant branch; and the air conditioning unit is also used to control the flow of the subcooling medium according to the degree of subcooling.

[0010] Furthermore, it also includes: a flow meter located at the refrigerant inlet of the condenser, used to detect the refrigerant flow entering the condenser; a first temperature sensor located at the refrigerant inlet of the condenser, used to detect the inlet temperature of the condenser; a first pressure sensor located at the refrigerant inlet of the condenser, used to detect the inlet pressure of the condenser; a second temperature sensor located on the main refrigerant branch, used to detect the main refrigerant temperature; a second pressure sensor located on the main refrigerant branch, used to detect the main refrigerant pressure; a third temperature sensor located on the subcooled refrigerant branch, used to detect the for detecting the temperature of the subcooled refrigerant; a third pressure sensor, located on the subcooled refrigerant branch and between the subcooling device and the throttling device, for detecting the pressure of the subcooled refrigerant; an ambient temperature sensor, located in the room where the air-conditioning unit is located, for detecting the indoor ambient temperature; wherein the refrigerant flow of the condenser, the inlet temperature of the condenser, the inlet pressure of the condenser, the main refrigerant temperature, the main refrigerant pressure, the subcooled refrigerant temperature, the subcooled refrigerant pressure and the indoor ambient temperature are used to control the operation of the main refrigerant branch and the subcooled refrigerant branch.

[0011] According to another aspect of an embodiment of the present invention, there is provided an air-conditioning unit control method, which is applied to an air-conditioning unit as described above, and the method comprises: detecting whether the air-conditioning unit needs to be supercooled; when supercooling is not required, controlling the main refrigerant branch to be turned on; when supercooling is required, controlling the supercooling refrigerant branch to be turned on, and obtaining the operating parameters and environmental parameters of the air-conditioning unit, and controlling the operation of the supercooling refrigerant branch according to the operating parameters and the environmental parameters of the air-conditioning unit.

[0012] Furthermore, detecting whether the air-conditioning unit needs to be supercooled includes: obtaining the indoor ambient temperature and a preset ambient temperature range, and determining whether the indoor ambient temperature is greater than the maximum value of the preset ambient temperature range; detecting the supercooling degree of the air-conditioning unit, and determining whether the supercooling degree is less than a preset supercooling degree; when the indoor ambient temperature is greater than the maximum value of the preset ambient temperature range, or the supercooling degree is less than the preset supercooling degree, determining that supercooling is required; otherwise, determining that supercooling is not required.

[0013] Furthermore, the operation of the subcooling refrigerant branch is controlled according to the operating parameters of the air-conditioning unit and the environmental parameters, including: obtaining a preset flow rate of the subcooling medium of the subcooling device; determining a flow correction coefficient of the subcooling medium according to the operating parameters of the air-conditioning unit and the environmental parameters; calculating a real-time flow rate of the subcooling medium according to the preset flow rate of the subcooling medium and the flow correction coefficient, and controlling the subcooling device to perform subcooling according to the real-time flow rate of the subcooling medium.

[0014] Furthermore, the operating parameters of the air-conditioning unit include at least: the refrigerant flow rate of the condenser, the inlet temperature of the condenser, the inlet pressure of the condenser, the main refrigerant temperature, the main refrigerant pressure, the subcooling refrigerant temperature, and the subcooling refrigerant pressure; the environmental parameters include at least: the indoor ambient temperature and the preset ambient temperature range; the flow correction coefficient of the subcooling medium is determined according to the operating parameters of the air-conditioning unit and the environmental parameters, including: calculating a first enthalpy value according to the inlet temperature of the condenser and the inlet pressure of the condenser, calculating a second enthalpy value according to the main refrigerant temperature and the main refrigerant pressure, and calculating a second enthalpy value according to the subcooling refrigerant temperature. and the subcooled refrigerant pressure to calculate the third enthalpy value; calculate the cooling capacity Q1 of the main refrigerant branch according to the refrigerant flow of the condenser, the first enthalpy value and the second enthalpy value; wherein, Q1 = m1*(hx2-ho1), m1 is the refrigerant flow of the condenser, hx2 is the second enthalpy value, and ho1 is the first enthalpy value; calculate the cooling capacity Q2 of the subcooled refrigerant branch according to the refrigerant flow of the condenser, the first enthalpy value and the third enthalpy value; wherein, Q2 = m1*(hy2-ho1), hy2 is the third enthalpy value; calculate the flow correction coefficient W of the subcooled medium by the following formula: Wherein, Tc is the indoor ambient temperature, Tm is the minimum value of the preset ambient temperature range, and Tn is the maximum value of the preset ambient temperature range.

[0015] Furthermore, after controlling the supercooling device to perform supercooling according to the real-time flow of the supercooling medium, it also includes: re-detecting the indoor ambient temperature and the supercooling degree; when the indoor ambient temperature is lower than the maximum value of the preset ambient temperature range or the supercooling degree is greater than the preset supercooling degree, and when the cooling capacity Q2 of the supercooling refrigerant branch is greater than the cooling capacity Q1 of the main refrigerant branch, controlling the supercooling refrigerant branch to be disconnected, and controlling the main refrigerant branch to be connected.

[0016] 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.

[0017] In the present invention, an air conditioning unit with improved supercooling is provided, wherein a main refrigerant branch and a supercooling refrigerant branch are provided between a condenser and a throttling device, the supercooling refrigerant branch is provided in parallel with the main refrigerant branch, and the refrigerant flowing through the cold refrigerant branch is supercooled and then passed into the throttling device and provided with a control valve, so as to control the on-off of the main refrigerant branch and the supercooling refrigerant branch in combination with the supercooling of the air conditioning unit. The supercooling of the air conditioning unit is compensated by the supercooling refrigerant branch, thereby improving the refrigeration effect and refrigeration efficiency of the air conditioning unit, and ensuring the reliable operation of the air conditioning unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of an optional structure of an air conditioning unit according to an embodiment of the present invention;

[0019] Figure 2 is an optional flow chart of the air conditioning unit control method according to an embodiment of the present invention.

[0020] Description of reference numerals:

[0021] 1. Compressor; 2. Four-way reversing valve; 3. Condenser; 4. Dry filter; 5. Throttle valve; 6. Liquid supply stop valve; 7. Evaporator; 8. Air suction stop valve; 9. Vapor-liquid separator; 10. First pressure sensor; 11. First temperature sensor; 12. Flow meter; 13. Condensation temperature sensitivity package; 14. First control valve; 15. Second control valve; 16. Subcooling device; 17. Second temperature sensor; 18. Second pressure sensor; 19. Third temperature sensor; 20. Third pressure sensor; 21. Ambient temperature sensor. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0024] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0025] It should be understood that although the terms first, second, third, etc. may be used to describe controllers in embodiments of the present invention, these controllers should not be limited to these terms. These terms are only used to distinguish controllers connected to different devices. For example, without departing from the scope of embodiments of the present invention, a first controller may also be referred to as a second controller, and similarly, a second controller may also be referred to as a first controller.

[0026] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0027] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0028] The optional embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0029] Example 1

[0030] In a preferred embodiment 1 of the present invention, an air conditioning unit is provided, which may be a unit with a large refrigeration capacity, such as an air conditioning unit for freezing and refrigeration or an air conditioning unit for cold storage. 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:

[0031] The compressor 1, the condenser 3, the throttle valve (electronic expansion valve) 5 and the evaporator 7 are connected in sequence; Figure 1 As shown, a four-way reversing valve 2, a drying filter 4, a liquid supply stop valve 6, an air suction stop valve 8 and a vapor-liquid separator 9 are also provided. In the refrigeration operation, the refrigerant flows out from the exhaust port of the compressor 1, passes through the four-way reversing valve 2 and reaches the condenser 3 for condensation. After the refrigerant is liquefied and filtered by the drying filter 4, it flows to the electronic expansion valve 5 for throttling, enters the evaporator 7 through the liquid supply stop valve 6, and the refrigerant coming out of the evaporator 7 returns to the vapor-liquid separator 9 through the air suction stop valve 8 to separate the refrigerant. The liquid refrigerant accumulates at the bottom of the vapor-liquid separator, and then enters the air suction end of the compressor 1 to start the next refrigeration cycle;

[0032] A main refrigerant branch is provided between the refrigerant outlet of the condenser and the throttling device, for passing the refrigerant at the refrigerant outlet of the condenser into the throttling device. Figure 1 As shown, one end of the main refrigerant branch is connected to the refrigerant outlet of the condenser, and the other end is connected to the dry filter 4. According to the normal flow path, the refrigerant is liquefied from the condenser 3 and flows to the dry filter 4 through the main refrigerant branch;

[0033] In addition to the main refrigerant branch, the air conditioning unit in the present invention is also provided with a subcooled refrigerant branch, which is arranged in parallel with the main refrigerant branch, one end of which is connected to the refrigerant outlet of the condenser, and the other end is connected to the throttling device, and optionally, Figure 1 As shown, the other end is connected to the dry filter 4. The supercooled refrigerant branch is provided with a supercooling device for supercooling the refrigerant flowing through the cold refrigerant branch and passing it into the throttling device. The refrigerant is liquefied from the condenser 3 and then passes through the cooling device 16 before flowing to the dry filter 4;

[0034] In order to realize the control of the above-mentioned main refrigerant branch and the subcooling refrigerant branch, a control valve is also installed, which is used to control the on and off of the main refrigerant branch and the subcooling refrigerant branch according to the subcooling degree of the air-conditioning unit; wherein, when subcooling is not required, the main refrigerant branch is controlled to be connected; when subcooling is required, the subcooling refrigerant branch is controlled to be connected, and the operating parameters and environmental parameters of the air-conditioning unit are obtained, and the operation of the subcooling refrigerant branch is controlled according to the operating parameters of the air-conditioning unit and the environmental parameters.

[0035] In the above embodiment, an air conditioning unit with improved supercooling is provided, wherein a main refrigerant branch and a supercooling refrigerant branch are provided between the condenser and the throttling device, the supercooling refrigerant branch is provided in parallel with the main refrigerant branch, and the refrigerant flowing through the cold refrigerant branch is supercooled and then passed into the throttling device and provided with a control valve to control the on-off of the main refrigerant branch and the supercooling refrigerant branch in combination with the supercooling of the air conditioning unit. The supercooling of the air conditioning unit is compensated by the supercooling refrigerant branch, thereby improving the refrigeration effect and refrigeration efficiency of the air conditioning unit and ensuring the reliable operation of the air conditioning unit.

[0036] In an optional embodiment of the present invention, the control valve includes: a first control valve 14, located on the main refrigerant branch, used to control the on-off of the main refrigerant branch; a second control valve 15, located on the subcooling refrigerant branch, used to control the on-off of the subcooling refrigerant branch. The first control valve and the second control valve are respectively used to control the on-off of the main refrigerant branch and the subcooling refrigerant branch, so as to facilitate flexible control of the air-conditioning unit, such as opening the main refrigerant branch or the subcooling refrigerant branch separately, or opening the main refrigerant branch and the subcooling refrigerant branch at the same time. The specific control can be controlled according to the degree of subcooling, that is, the on-off of the main refrigerant branch and the subcooling refrigerant branch is combined with the refrigeration demand to meet the refrigeration demand of the unit, especially the unit with high refrigeration demand such as the air-conditioning unit for cold storage.

[0037] In another optional embodiment of the present invention, the control valve includes: a three-way valve, the first end of which is connected to the refrigerant outlet of the condenser, the second end of which is connected to the inlet of the main refrigerant branch, and the third end of which is connected to the inlet of the subcooled refrigerant branch, for controlling the on-off of the main refrigerant branch and the subcooled refrigerant branch. The three-way valve is located at the junction of the refrigerant outlet of the condenser and the main refrigerant branch and the subcooled refrigerant branch. When the three ports are connected, the refrigerant at the condenser outlet enters the main refrigerant branch and the subcooled refrigerant branch. When the first end is connected to the second end, the refrigerant at the condenser outlet enters the main refrigerant branch. When the first end is connected to the third end, the refrigerant at the condenser outlet enters the subcooled refrigerant branch. The above-mentioned three-way valve solution only needs to set up one valve, and the control is realized by the air conditioning unit controller, which simplifies the pipeline connection method and simply and effectively realizes the on-off control of the main refrigerant branch and the subcooled refrigerant branch.

[0038] like Figure 1As shown, the supercooling refrigerant branch is provided with a supercooling device, which includes: a supercooling medium for providing cooling capacity; the supercooling medium can be in various forms, such as low-temperature water, and the temperature of the refrigerant is reduced by heat exchange between low-temperature water and the refrigerant. A heat exchanger, the supercooling medium exchanges heat with the refrigerant on the supercooling refrigerant branch through the heat exchanger; the air conditioning unit is also used to control the flow of the supercooling medium according to the degree of supercooling. The flow regulation of the above-mentioned supercooling medium is also under the consideration of supercooling control. For the case of insufficient supercooling, the flow of the supercooling medium can be increased, thereby providing more cooling capacity for the refrigerant and improving the degree of supercooling. In the case of high supercooling, the flow of the supercooling medium can be appropriately reduced to save energy. Therefore, the supercooling device can not only provide cooling capacity, but also intelligently adjust the degree of supercooling, further improving the supercooling adjustment effect of the air conditioning unit.

[0039] Furthermore, the air conditioning unit also includes: a flow meter, located at the refrigerant inlet of the condenser, for detecting the refrigerant flow entering the condenser; a first temperature sensor, located at the refrigerant inlet of the condenser, for detecting the inlet temperature of the condenser; a first pressure sensor, located at the refrigerant inlet of the condenser, for detecting the inlet pressure of the condenser; a second temperature sensor, located on the main refrigerant branch, for detecting the main refrigerant temperature; a second pressure sensor, located on the main refrigerant branch, for detecting the main refrigerant pressure; a third temperature sensor, located on the subcooling refrigerant branch, for detecting the subcooling refrigerant temperature; a third pressure sensor, located on the subcooling refrigerant branch, and located between the subcooling device and the throttling device, for detecting the subcooling refrigerant pressure; an ambient temperature sensor, located in the room where the air conditioning unit is located, for detecting the indoor ambient temperature. Among them, the refrigerant flow of the condenser, the inlet temperature of the condenser, the inlet pressure of the condenser, the main refrigerant temperature, the main refrigerant pressure, the subcooling refrigerant temperature, the subcooling refrigerant pressure and the indoor ambient temperature are used to control the operation of the main refrigerant branch and the subcooling refrigerant branch. Figure 1 As shown, according to the normal flow path, the refrigerant is liquefied from the condenser 3 and flows to the drying filter 4 through the solenoid valve 14, and the flow path is provided with a second temperature sensor 17 and a second pressure sensor 18; when the solenoid valve 14 is closed when a small degree of supercooling is detected in the system, the refrigerant is liquefied from the condenser 3 and flows through the solenoid valve 15 through the cooling device 16 and then flows to the drying filter 4, and the flow path is provided with a third temperature sensor 19 and a third pressure sensor 20; the flow meter 12, the first temperature sensor 11 and the first pressure sensor 10 are provided at the inlet of the condenser 3, and the ambient temperature sensor 21 is provided on the evaporator.

[0040] The temperature and pressure sensors and flowmeters are used to detect the operating parameters and environmental parameters of the air-conditioning unit, and then determine the parameters such as supercooling according to the operating parameters and environmental parameters of the air-conditioning unit, and control the operation of the main refrigerant branch and the supercooling refrigerant branch. The operation of the air-conditioning unit is accurately controlled by the parameters detected by the sensors to avoid a series of problems such as reduced cooling capacity, reduced cooling efficiency, poor cooling effect, increased power consumption of the refrigeration system, reduced energy efficiency, increased compressor loss, reduced reliability of the compressor and the overall unit operation, and service life caused by low supercooling, thereby improving the cooling effect and efficiency of the air-conditioning unit, ensuring the reliable operation of the air-conditioning unit, and improving the intelligence of the air-conditioning unit control.

[0041] Example 2

[0042] 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:

[0043] S202: Detect whether the air conditioning unit needs to be overcooled;

[0044] S204: When supercooling is not required, controlling the main refrigerant branch to be turned on;

[0045] S206: When supercooling is required, the supercooling refrigerant branch is controlled to be turned on, and the operating parameters and environmental parameters of the air-conditioning unit are obtained, and the operation of the supercooling refrigerant branch is controlled according to the operating parameters and environmental parameters of the air-conditioning unit.

[0046] In the above embodiment, an air conditioning unit for improving supercooling is provided, wherein a main refrigerant branch and a supercooling refrigerant branch are provided between a condenser and a throttling device, the supercooling refrigerant branch is provided in parallel with the main refrigerant branch, the refrigerant flowing through the cold refrigerant branch is supercooled and then passed into the throttling device and provided with a control valve, so as to control the on-off of the main refrigerant branch and the supercooling refrigerant branch in combination with the supercooling of the air conditioning unit. Specifically, when supercooling is not required, the main refrigerant branch is controlled to be turned on, and when supercooling is required, the supercooling refrigerant branch is controlled to be turned on, and the operating parameters and environmental parameters of the air conditioning unit are obtained, and the operation of the supercooling refrigerant branch is controlled according to the operating parameters and environmental parameters of the air conditioning unit. The supercooling of the air conditioning unit is compensated by the supercooling refrigerant branch, thereby improving the refrigeration effect and refrigeration efficiency of the air conditioning unit and ensuring the reliable operation of the air conditioning unit. And corresponding control is performed by the operating parameters and environmental parameters of the air conditioning unit, thereby improving the intelligent degree of control of the air conditioning unit.

[0047] In an optional embodiment of the present invention, detecting whether the air-conditioning unit needs to be overcooled includes: obtaining the indoor ambient temperature and a preset ambient temperature range, determining whether the indoor ambient temperature is greater than the maximum value of the preset ambient temperature range; detecting the supercooling degree of the air-conditioning unit, and determining whether the supercooling degree is less than the preset supercooling degree; when the indoor ambient temperature is greater than the maximum value of the preset ambient temperature range, or the supercooling degree is less than the preset supercooling degree, determining that supercooling is required; otherwise, determining that supercooling is not required. When the system detects that the indoor ambient temperature, such as the storage temperature, deviates from the storage temperature range set for the cold storage, or the supercooling degree is less than 3 (other values ​​can also be set according to the actual operation of the air-conditioning unit), the unit may be in shutdown mode (storage temperature deviates from the set value) or is in refrigeration operation but the refrigeration efficiency is low. Therefore, after the unit is started or the unit is in refrigeration operation, it is determined that supercooling is required, and then the supercooling degree is increased through the supercooling refrigerant branch and the supercooling device to accelerate the refrigeration efficiency. The above-mentioned indoor ambient temperature and supercooling degree can accurately reflect the current status of the air-conditioning unit, and then through subsequent supercooling control, effective regulation of the air-conditioning unit can be achieved, especially supercooling degree regulation, to ensure the normal operation of the air-conditioning unit.

[0048] When supercooling is not required, the main refrigerant branch is controlled to be open, and the cooling demand of the air-conditioning unit can be met by the main refrigerant branch; when supercooling is required, the main refrigerant branch and the supercooling refrigerant branch can be used, or the supercooling refrigerant branch can be used alone for supercooling. When the supercooling refrigerant branch is used for supercooling, the operation of the supercooling refrigerant branch is controlled according to the operating parameters and environmental parameters of the air-conditioning unit, specifically including: obtaining the preset flow rate of the supercooling medium of the supercooling device; determining the flow correction coefficient of the supercooling medium according to the operating parameters and environmental parameters of the air-conditioning unit; calculating the real-time flow rate of the supercooling medium according to the preset flow rate of the supercooling medium and the flow correction coefficient, that is, multiplying the preset flow rate of the supercooling medium and the flow correction coefficient to obtain the real-time flow rate of the supercooling medium, and controlling the supercooling device for supercooling according to the real-time flow rate of the supercooling medium. Since the operating parameters and environmental parameters of the air-conditioning unit are real-time parameters, the flow correction coefficient determined by the real-time operating parameters and environmental parameters can adjust the subcooling in real time, so that the subcooling adjustment adapts to the current operating state of the air-conditioning unit, thereby achieving the effect of dynamic adjustment, so that the subcooling of the air-conditioning unit reaches the optimal value, thereby better improving the refrigeration effect and refrigeration efficiency of the air-conditioning unit and ensuring the reliable operation of the air-conditioning unit.

[0049] Specifically, the operating parameters of the air-conditioning unit include at least: the refrigerant flow rate of the condenser, the inlet temperature of the condenser, the inlet pressure of the condenser, the main refrigerant temperature, the main refrigerant pressure, the subcooling refrigerant temperature, and the subcooling refrigerant pressure; the environmental parameters include at least: the indoor ambient temperature and the preset ambient temperature range; the flow correction coefficient of the subcooling medium is determined according to the operating parameters and environmental parameters of the air-conditioning unit, including: calculating the first enthalpy value according to the inlet temperature of the condenser and the inlet pressure of the condenser, calculating the second enthalpy value according to the main refrigerant temperature and the main refrigerant pressure, and calculating the flow correction coefficient of the subcooling medium according to the subcooling refrigerant temperature. The third enthalpy value is calculated according to the temperature and the subcooled refrigerant pressure; the cooling capacity Q1 of the main refrigerant branch is calculated according to the refrigerant flow rate of the condenser, the first enthalpy value and the second enthalpy value; wherein, Q1=m1*(hx2-ho1), m1 is the refrigerant flow rate of the condenser, hx2 is the second enthalpy value, and ho1 is the first enthalpy value; the cooling capacity Q2 of the subcooled refrigerant branch is calculated according to the refrigerant flow rate of the condenser, the first enthalpy value and the third enthalpy value; wherein, Q2=m1*(hy2-ho1), hy2 is the third enthalpy value; the flow correction coefficient W of the subcooled medium is calculated by the following formula: Wherein, Tc is the indoor ambient temperature, Tm is the minimum value of the preset ambient temperature range, and Tn is the maximum value of the preset ambient temperature range. The above-mentioned flow correction coefficient of the supercooling medium adopts the ambient temperature and the cooling capacity Q1 of the main refrigerant branch and the cooling capacity Q2 of the supercooling refrigerant branch, and performs difference and ratio calculations to obtain the influence factor value of the ambient temperature and the cooling capacity, and obtains the accurate flow value of the supercooling medium, so that the supercooling effect of the supercooling device is optimized.

[0050] The following example is used to illustrate that the inlet temperature To1 and the inlet pressure Po1 of the condenser 3 before the flow meter 12 are detected to obtain the enthalpy value ho1; the outlet temperature Tx2 and the outlet pressure Px2 of the condenser 3 on the main refrigerant flow path where the solenoid valve 14 is located are detected to obtain the enthalpy value hx2; the temperature Ty2 and the pressure Py2 after the subcooling device 16 on the subcooling refrigerant flow path where the solenoid valve 15 is located are detected to obtain the enthalpy value hy2; the refrigeration flow rate from the flow meter 12 through the condenser 3 is measured as m1, and the refrigeration flow rate from the condenser 3 through the main refrigerant flow path where the solenoid valve 14 is located is measured as m2. The cooling capacity is Q1, and the degree of subcooling Td1=Tx2-To1; the cooling capacity of the subcooling refrigerant flow path from the condenser 3 through the solenoid valve 15 is Q2, and the degree of subcooling Td2=Ty2-To1; the cooling capacity of the main refrigerant branch is Q1=m1*(hx2-ho1), and the cooling capacity of the subcooling refrigerant branch is Q2=m1*(hy2-ho1). The set storage temperature of the cold storage is [Tm, Tn]. The current storage temperature detected at a certain moment is Tc, and the subcooling flow rate or the volume of the subcooling medium preset by the subcooling device is V. When it is detected at a certain moment that Tc>Tn or the degree of subcooling Td=Td1<3, the cooling capacity Q=Q1=m1*(hx2-ho1), so the solenoid valve 14 is closed and the solenoid valve 15 is opened. At this time, Td=Td2=Ty2-To1, Q=Q2=m1*(hy2-ho1), the subcooling flow rate of the subcooling device or the volume of the subcooling medium is Make adjustments.

[0051] After the supercooling device is controlled to perform supercooling according to the real-time flow rate of the supercooling medium, it also includes: re-detecting the indoor ambient temperature and the degree of supercooling; when the indoor ambient temperature is less than the maximum value of the preset ambient temperature range or the degree of supercooling is greater than the preset degree of supercooling, and the cooling capacity Q2 of the supercooling refrigerant branch is greater than the cooling capacity Q1 of the main refrigerant branch, the supercooling refrigerant branch is controlled to be disconnected, and the main refrigerant branch is controlled to be connected. When the supercooling refrigerant branch is connected, the main refrigerant branch is disconnected, and the cooling capacity Q2 of the supercooling refrigerant branch is greater than the cooling capacity Q1 of the main refrigerant branch, which means that when the supercooling refrigerant branch is connected, its cooling capacity Q2 is greater than the cooling capacity Q1 when the main refrigerant branch is connected, that is, the cooling capacity of the unit in the lower period of time needs to be continuously greater than that in the upper period of time, which can verify and ensure that the control effect is effective, and at the same time, it can also greatly improve the refrigeration effect and meet the needs of cold storage. When it is detected that the system cooling capacity has increased, and the supercooling degree has increased or the storage temperature has reached the set range, it means that the adjustment of the cooling device has been completed, and the unit closes the supercooling device and the supercooling refrigerant branch, and operates in the normal cooling mode. The above adjustment can control the operation of the air-conditioning unit in real time, and close the supercooling in time when the supercooling degree meets the demand, avoiding unnecessary waste of cooling capacity or over-adjustment, effectively improving the supercooling degree and cooling effect of the refrigeration system, and improving the reliability of the unit operation.

[0052] The air conditioning unit in the present invention increases the cooling capacity by increasing the degree of supercooling through the subcooled refrigerant branch, and improves the refrigeration efficiency so that the cold storage can reach the set temperature as soon as possible. In the existing units, no subcooling device is provided. Even if a subcooling section (part condensation and part subcooling) is added when the condenser is designed, the degree of supercooling is still small during actual operation due to factors such as insufficient refrigerant and too high outer ring, and the refrigeration effect of the unit is not good. In the present invention, the main refrigerant branch and the subcooled refrigerant branch can be used separately or simultaneously, and the flow path is switched according to the refrigeration demand, which can further ensure the system's degree of supercooling and refrigeration efficiency.

[0053] Example 3

[0054] 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.

[0055] In the above embodiment, an air conditioning unit with improved supercooling is provided, wherein a main refrigerant branch and a supercooling refrigerant branch are provided between the condenser and the throttling device, the supercooling refrigerant branch is provided in parallel with the main refrigerant branch, and the refrigerant flowing through the cold refrigerant branch is supercooled and then passed into the throttling device and provided with a control valve to control the on-off of the main refrigerant branch and the supercooling refrigerant branch in combination with the supercooling of the air conditioning unit. The supercooling of the air conditioning unit is compensated by the supercooling refrigerant branch, thereby improving the refrigeration effect and refrigeration efficiency of the air conditioning unit and ensuring the reliable operation of the air conditioning unit.

[0056] 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.

[0057] 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: A compressor, a condenser, a throttling device and an evaporator connected in sequence; A main refrigerant branch, one end of which is connected to the refrigerant outlet of the condenser, and the other end of which is connected to the throttling device, and is used to pass the refrigerant at the refrigerant outlet of the condenser into the throttling device; A subcooling refrigerant branch is arranged in parallel with the main refrigerant branch, one end of which is connected to the refrigerant outlet of the condenser, and the other end is connected to the throttling device. The subcooling refrigerant branch is provided with a subcooling device for supercooling the refrigerant flowing through the subcooling refrigerant branch and then passing it into the throttling device; A control valve is used to control the on-off of the main refrigerant branch and the subcooling refrigerant branch according to the subcooling degree of the air-conditioning unit; wherein, the control valve is used to control the conduction of the main refrigerant branch when subcooling is not required; when subcooling is required, the subcooling refrigerant branch is controlled to be conducted, and the operating parameters and environmental parameters of the air-conditioning unit are obtained, and the operation of the subcooling refrigerant branch is controlled according to the operating parameters and environmental parameters of the air-conditioning unit; wherein, when subcooling is required, the preset flow rate of the subcooling medium of the subcooling device is obtained, and the flow rate of the subcooling medium is determined according to the operating parameters and environmental parameters of the air-conditioning unit. A flow correction coefficient is used to calculate the real-time flow of the supercooling medium according to the preset flow of the supercooling medium and the flow correction coefficient, and the supercooling device is controlled to perform supercooling according to the real-time flow of the supercooling medium; the operating parameters of the air-conditioning unit include at least: the refrigerant flow of the condenser, the inlet temperature of the condenser, the inlet pressure of the condenser, the main refrigerant temperature, the main refrigerant pressure, the supercooling refrigerant temperature, and the supercooling refrigerant pressure; the environmental parameters include at least: the indoor ambient temperature and the preset ambient temperature range; the flow correction coefficient of the supercooling medium is determined according to the operating parameters of the air-conditioning unit and the environmental parameters, including: Calculating a first enthalpy value according to the inlet temperature of the condenser and the inlet pressure of the condenser, calculating a second enthalpy value according to the main refrigerant temperature and the main refrigerant pressure, and calculating a third enthalpy value according to the subcooling refrigerant temperature and the subcooling refrigerant pressure; Calculate the cooling capacity Q1 of the main refrigerant branch according to the refrigerant flow rate of the condenser, the first enthalpy value and the second enthalpy value; wherein Q1=m1*(hx2-ho1), m1 is the refrigerant flow rate of the condenser, hx2 is the second enthalpy value, and ho1 is the first enthalpy value; Calculate the cooling capacity Q2 of the supercooling refrigerant branch according to the refrigerant flow rate of the condenser, the first enthalpy value and the third enthalpy value; wherein Q2=m1*(hy2-ho1), hy2 is the third enthalpy value; The flow correction coefficient W of the supercooling medium is calculated by the following formula: W= * , wherein Tc is the indoor ambient temperature, Tm is the minimum value of the preset ambient temperature range, and Tn is the maximum value of the preset ambient temperature range.

2. The air conditioning unit according to claim 1, characterized in that: The control valve comprises: A first control valve, located on the main refrigerant branch, for controlling the on-off of the main refrigerant branch; The second control valve is located on the subcooling refrigerant branch and is used to control the on-off of the subcooling refrigerant branch.

3. The air conditioning unit according to claim 1, characterized in that: The control valve comprises: A three-way valve, a first end of which is connected to the refrigerant outlet of the condenser, a second end of which is connected to the inlet of the main refrigerant branch, and a third end of which is connected to the inlet of the subcooling refrigerant branch, is used to control the on-off of the main refrigerant branch and the subcooling refrigerant branch.

4. The air conditioning unit according to claim 1, characterized in that: The supercooling device comprises: Supercooling medium, used to provide cooling capacity; A heat exchanger, through which the supercooling medium exchanges heat with the refrigerant on the supercooling refrigerant branch.

5. The air conditioning unit according to claim 1, characterized in that: Also includes: A flow meter, located at the refrigerant inlet of the condenser, for detecting the refrigerant flow entering the condenser; A first temperature sensor, located at the refrigerant inlet of the condenser, for detecting the inlet temperature of the condenser; A first pressure sensor, located at the refrigerant inlet of the condenser, for detecting the inlet pressure of the condenser; A second temperature sensor is located on the main refrigerant branch and is used to detect the temperature of the main refrigerant; A second pressure sensor is located on the main refrigerant branch and is used to detect the main refrigerant pressure; A third temperature sensor is located on the subcooled refrigerant branch and is used to detect the temperature of the subcooled refrigerant; A third pressure sensor is located on the subcooling refrigerant branch and between the subcooling device and the throttling device, and is used to detect the pressure of the subcooling refrigerant; The ambient temperature sensor is located in the room where the air conditioning unit is located and is used to detect the indoor ambient temperature.

6. A method for controlling an air conditioning unit, applied to the air conditioning unit according to any one of claims 1 to 5, characterized in that: The method comprises: Detecting whether the air conditioning unit needs to be overcooled; When supercooling is not required, the main refrigerant branch is controlled to be open; When supercooling is required, the supercooling refrigerant branch is controlled to be turned on, and the operating parameters and environmental parameters of the air-conditioning unit are obtained, and the operation of the supercooling refrigerant branch is controlled according to the operating parameters and the environmental parameters of the air-conditioning unit.

7. The method according to claim 6, characterized in that Detecting whether the air conditioning unit needs to be overcooled includes: Acquire the indoor ambient temperature and a preset ambient temperature range, and determine whether the indoor ambient temperature is greater than a maximum value of the preset ambient temperature range; Detecting the subcooling degree of the air conditioning unit, and determining whether the subcooling degree is less than a preset subcooling degree; When the indoor ambient temperature is greater than the maximum value of the preset ambient temperature range, or the supercooling degree is less than the preset supercooling degree, determining that supercooling is required; Otherwise, it is determined that subcooling is not required.

8. The method according to claim 7, characterized in that Controlling the operation of the supercooling refrigerant branch according to the operating parameters of the air conditioning unit and the environmental parameters includes: Obtaining a preset flow rate of a supercooling medium of a supercooling device; Determining a flow correction coefficient of the supercooling medium according to the operating parameters of the air conditioning unit and the environmental parameters; The real-time flow rate of the supercooling medium is calculated according to the preset flow rate of the supercooling medium and the flow rate correction coefficient, and the supercooling device is controlled to perform supercooling according to the real-time flow rate of the supercooling medium.

9. The method according to claim 8, characterized in that After controlling the supercooling device to perform supercooling according to the real-time flow rate of the supercooling medium, the method further includes: re-detecting the indoor ambient temperature and the degree of supercooling; When the indoor ambient temperature is lower than the maximum value of the preset ambient temperature range or the supercooling degree is greater than the preset supercooling degree, and the cooling capacity Q2 of the supercooling refrigerant branch is greater than the cooling capacity Q1 of the main refrigerant branch, the supercooling refrigerant branch is controlled to be disconnected, and the main refrigerant branch is controlled to be connected.

10. 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 6 to 9 when executed by a computer processor.

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