A refrigeration unit, an air conditioning system and a control method thereof

Abstract

The present invention discloses a refrigeration unit, an air-conditioning system, and a control method thereof, which relate to the field of air-conditioning and solve the problem in the prior art that the amount of refrigerant sprayed through the capillary tube is too large, resulting in a large loss of cooling capacity and a deterioration in the refrigeration effect of the refrigeration unit. The refrigeration unit includes a refrigeration circuit and a liquid spray branch, and the refrigeration circuit is formed by sequentially connecting the exhaust port of the compressor, the condenser, the evaporator, the gas-liquid separator, and the air intake of the compressor; the liquid spray branch is arranged in parallel with the evaporator and the gas-liquid separator, and at least two stages of throttling and pressure reducing components are connected in series on the liquid spray branch, and the pressure drop of the throttling and pressure reducing component on the side close to the compressor is greater than the pressure drop of the throttling and pressure reducing component on the side close to the condenser. The refrigeration unit can reduce the amount of refrigerant entering the compressor through the liquid spray branch through the barrier effect of at least two stages of throttling and pressure reducing components, thereby reducing the cooling capacity loss of the refrigeration unit caused by liquid spraying, and further improving the refrigeration effect of the refrigeration unit, reducing power consumption, and increasing the performance coefficient.

Description

Technical Field

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

[0002] Compared to conventional air conditioning refrigeration units, cold storage refrigeration units operate at lower temperatures and higher pressure ratios, resulting in higher compressor exhaust temperatures. During summer cooling, existing cold storage refrigeration units often experience compressor shutdowns due to overheating of the compressor motor. To address this, existing cold storage refrigeration units feature a bypass branch after the filter drier, connected in parallel with the evaporator. This bypass branch lowers the compressor exhaust temperature.

[0003] Figure 1 The figure shows a schematic diagram of a refrigeration unit for an existing cold storage. Figure 1 As shown, a conventional cold storage refrigeration unit includes a compressor 1, a condenser 2, a filter drier 3, an evaporator 4, and a gas-liquid separator 5. The unit also includes a bypass branch consisting of a solenoid valve 6 and a capillary tube 7, which is connected in parallel at both ends of the evaporator 4 and the gas-liquid separator 5. When the unit is operating in cooling mode, the high-temperature, high-pressure refrigerant discharged from the compressor 1 enters the condenser 2. After the liquid refrigerant is filtered by the filter drier 3, the refrigerant is split into two paths: one path enters the evaporator 4 and the gas-liquid separator 5 and returns to the intake port of the compressor 1; the other path returns directly to the intake port of the compressor 1 via the bypass branch. When the capillary tube 7 compresses the liquid refrigerant from the condenser 2 outlet back to the intake port of the compressor 1, the refrigerant changes to a gas-liquid two-phase state through the capillary tube 7. The gas-liquid two-phase refrigerant absorbs heat and vaporizes within the compressor 1, thereby lowering the exhaust temperature and maintaining the normal operation of the compressor 1.

[0004] However, the applicant discovered that when a cold storage refrigeration unit is in operation, the amount of refrigerant sprayed through the capillary tube 7 is excessive, significantly reducing the amount of refrigerant entering the evaporator 4. This results in significant cooling loss, which in turn leads to a decrease in the refrigeration efficiency of the refrigeration unit, increased power consumption, and a decrease in the coefficient of performance. Furthermore, when the high- and low-pressure ratio of the refrigeration unit exceeds the unit's operating range, the refrigeration unit is overloaded, resulting in reduced reliability and service life; it may even cause the refrigeration unit to shut down for protection, causing large fluctuations in indoor temperature and unstable storage temperature, affecting the storage of goods.

[0005] Therefore, it is urgent to improve the refrigeration unit in the prior art. Summary of the Invention

[0006] One of the objectives of the present invention is to provide a refrigeration unit that addresses the prior art technical problem of excessive refrigerant spray through the capillary tube, resulting in significant cooling loss and reduced cooling performance. The various technical benefits of the preferred technical solution of the present invention are detailed below.

[0007] To achieve the above objectives, the present invention provides the following technical solutions:

[0008] The refrigeration unit of the present invention includes a refrigeration circuit and a liquid injection branch, wherein the refrigeration circuit is formed by connecting the exhaust port of the compressor, the condenser, the evaporator, the gas-liquid separator and the suction port of the compressor in sequence; the liquid injection branch is arranged in parallel with the evaporator and the gas-liquid separator, and at least two stages of throttling and pressure reducing components are connected in series on the liquid injection branch, and the pressure drop of the throttling and pressure reducing component close to the compressor side is greater than the pressure drop of the throttling and pressure reducing component close to the condenser side.

[0009] According to a preferred embodiment, the liquid injection branch includes a first capillary tube and a second capillary tube, the first capillary tube and the second capillary tube are connected in series, and the other end of the first capillary tube is connected to the condenser, and the other end of the second capillary tube is connected to the suction port of the compressor.

[0010] According to a preferred embodiment, the diameter of the first capillary tube is 2.6-2.8 mm, and the length is 25-35 mm; the diameter of the second capillary tube is 2.3-2.5 mm, and the length is 55-65 mm.

[0011] According to a preferred embodiment, the liquid injection branch further includes a first control valve, and the first control valve is connected in series with the first capillary tube and the second capillary tube.

[0012] According to a preferred embodiment, the refrigeration unit further includes a first bypass branch, which is arranged in parallel with the throttling and pressure reducing component close to the compressor side, and a second control valve is provided on the first bypass branch.

[0013] According to a preferred embodiment, the refrigeration unit further includes a second bypass branch, which is arranged in parallel with the liquid injection branch, and a third control valve is provided on the second bypass branch.

[0014] The refrigeration unit provided by the present invention has at least the following beneficial technical effects:

[0015] The refrigeration unit of the present invention comprises a refrigeration circuit and a liquid spray branch, wherein the refrigeration circuit is formed by sequentially connecting the exhaust port of the compressor, the condenser, the evaporator, the gas-liquid separator, and the intake port of the compressor; the liquid spray branch is arranged in parallel with the evaporator and the gas-liquid separator, and because the liquid spray branch is connected in series with at least two stages of throttling and pressure reducing components, and the pressure drop of the throttling and pressure reducing components on the side close to the compressor is greater than the pressure drop of the throttling and pressure reducing components on the side close to the condenser, compared with the existing refrigeration unit, the refrigeration unit of the present invention can reduce the amount of refrigerant entering the compressor through the liquid spray branch through the blocking effect of at least two stages of throttling and pressure reducing components, thereby reducing the cooling loss of the refrigeration unit due to liquid spray, thereby improving the cooling effect of the refrigeration unit, reducing power consumption, and increasing the performance coefficient. That is, the refrigeration unit of the present invention solves the technical problem in the prior art that the amount of refrigerant sprayed through the capillary tube is too large, resulting in large cooling loss and poor cooling effect of the refrigeration unit.

[0016] A second object of the present invention is to provide an air conditioning system.

[0017] The air-conditioning system of the present invention comprises the refrigeration unit described in any one of the technical solutions of the present invention.

[0018] The air conditioning system provided by the present invention has at least the following beneficial technical effects:

[0019] The air-conditioning system of the present invention includes a refrigeration unit according to any one of the technical solutions of the present invention. Since the refrigeration effect of the refrigeration unit is improved, the power consumption is reduced, and the performance coefficient is increased, the refrigeration capacity of the air-conditioning system of the present invention can be improved, the power consumption is reduced, and the performance coefficient is increased.

[0020] The third object of the present invention is to provide a control method for a refrigeration unit.

[0021] The control method of a refrigeration unit according to any one of the technical solutions of the present invention comprises the following steps:

[0022] Get the exhaust temperature of the compressor;

[0023] comparing the exhaust gas temperature of the compressor with a first preset exhaust gas temperature;

[0024] When T1≥T 01 When T1<T 01 When the liquid injection branch is closed, T1 is the exhaust temperature of the compressor, T 01 It is the first preset exhaust temperature.

[0025] According to a preferred embodiment, when the liquid injection branch is opened, the following steps are also included:

[0026] Get the exhaust temperature of the compressor;

[0027] comparing the exhaust gas temperature of the compressor with a second preset exhaust gas temperature;

[0028] When T1≥T 02 When T1<T 02 When the first bypass branch is closed, T 02 >T 01 , T1 is the exhaust temperature of the compressor, T 02 is the second preset exhaust temperature.

[0029] According to a preferred embodiment, the control method of the refrigeration unit further includes the following steps:

[0030] Obtain the pressure ratio of the refrigeration unit or the exhaust parameters of the compressor;

[0031] Comparing the pressure ratio of the refrigeration unit with the preset pressure ratio of the refrigeration unit, or comparing the exhaust parameters of the compressor with the preset exhaust parameters;

[0032] When the pressure ratio of the refrigeration unit exceeds the preset pressure ratio of the refrigeration unit, or the exhaust parameter of the compressor exceeds the preset exhaust parameter, the first bypass branch and the second bypass branch are controlled to open;

[0033] When the pressure ratio of the refrigeration unit is less than the preset pressure ratio of the refrigeration unit, or the exhaust parameter of the compressor is less than the preset exhaust parameter, the first bypass branch is controlled to open and the second bypass branch is closed.

[0034] The control method of the refrigeration unit provided by the present invention has at least the following beneficial technical effects:

[0035] The control method of the refrigeration unit of any technical solution of the present invention obtains the exhaust temperature of the compressor, compares the exhaust temperature of the compressor with the first preset exhaust temperature, and when T1≥T 01 When T1<T 01 When the compressor is in the normal operation state, the step of controlling the closing of the liquid injection branch can not only maintain the normal operation of the compressor, but also reduce the amount of refrigerant entering the compressor through the liquid injection branch, thereby reducing the cooling loss of the refrigeration unit caused by the liquid injection, and further improving the cooling effect of the refrigeration unit, reducing power consumption and increasing the performance coefficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 It is a schematic diagram of a refrigeration unit in the prior art;

[0038] Figure 2 is a schematic diagram of a preferred embodiment of the refrigeration unit of the present invention;

[0039] Figure 3 It is a flow chart of a preferred embodiment of the control method of the refrigeration unit of the present invention.

[0040] In the figure: 1. Compressor; 2. Condenser; 3. Dry filter; 4. Evaporator; 5. Gas-liquid separator; 6. Solenoid valve; 7. Capillary tube; 8. First capillary tube; 9. Second capillary tube; 10. First control valve; 11. Second control valve; 12. Third control valve; 13. Liquid supply solenoid valve; 14. Electronic expansion valve. DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions, and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other implementations obtained by those of ordinary skill in the art without inventive effort are within the scope of protection of the present invention.

[0042] The following is attached with the instruction manual Figure 2 and 3 And embodiments 1 to 3 describe the refrigeration unit, air conditioning system and control method thereof of the present invention in detail.

[0043] Example 1

[0044] This embodiment describes the refrigeration unit of the present invention in detail.

[0045] The refrigeration unit of this embodiment includes a refrigeration circuit and a liquid injection branch. Preferably, the refrigeration circuit is formed by sequentially connecting the exhaust port of the compressor 1, the condenser 2, the evaporator 4, the gas-liquid separator 5 and the air intake of the compressor 1. Figure 2 Preferably, the liquid spray branch is connected in parallel with the evaporator 4 and the gas-liquid separator 5, and at least two stages of throttling and pressure reducing components are connected in series on the liquid spray branch, and the pressure drop of the throttling and pressure reducing component close to the compressor 1 is greater than the pressure drop of the throttling and pressure reducing component close to the condenser 2, as shown in FIG. Figure 2 As shown. Figure 2 As shown, the refrigeration circuit may further include a drying filter 3, which is arranged at the outlet end of the condenser 2. A liquid supply solenoid valve 13 and an electronic expansion valve 14 may also be provided at the inlet end of the evaporator 4, and the liquid supply solenoid valve 13 and the electronic expansion valve 14 are connected in series with the evaporator 4.

[0046] The refrigeration unit of this embodiment includes a refrigeration circuit and a liquid injection branch, wherein the refrigeration circuit is formed by sequentially connecting the exhaust port of the compressor 1, the condenser 2, the evaporator 4, the gas-liquid separator 5, and the intake port of the compressor 1; the liquid injection branch is arranged in parallel with the evaporator 4 and the gas-liquid separator 5. Because the liquid injection branch is connected in series with at least two stages of throttling and pressure reducing components, and the pressure drop of the throttling and pressure reducing components on the side close to the compressor 1 is greater than the pressure drop of the throttling and pressure reducing components on the side close to the condenser 2, compared with the existing refrigeration unit, the refrigeration unit of this embodiment can reduce the amount of refrigerant entering the compressor 1 through the liquid injection branch through the blocking effect of at least two stages of throttling and pressure reducing components, thereby reducing the cooling loss of the refrigeration unit caused by liquid injection, thereby improving the cooling effect of the refrigeration unit, reducing power consumption, and increasing the performance coefficient. That is, the refrigeration unit of this embodiment solves the technical problem in the prior art that the amount of refrigerant injected through the capillary tube is too large, resulting in large cooling loss and poor cooling effect of the refrigeration unit.

[0047] According to a preferred embodiment, the liquid injection branch includes a first capillary tube 8 and a second capillary tube 9, the first capillary tube 8 and the second capillary tube 9 are connected in series, and the other end of the first capillary tube 8 is connected to the condenser 2, and the other end of the second capillary tube 9 is connected to the suction port of the compressor 1, as shown in FIG. Figure 2 As shown. Preferably, the first capillary tube 8 has a diameter of 2.6-2.8 mm and a length of 25-35 mm; the second capillary tube 9 has a diameter of 2.3-2.5 mm and a length of 55-65 mm. More preferably, the first capillary tube 8 has a diameter of 2.7 mm and a length of 30 mm; the second capillary tube 9 has a diameter of 2.4 mm and a length of 60 mm. In the refrigeration unit of the preferred technical solution of this embodiment, the liquid injection branch includes two capillaries of different specifications. After the refrigerant discharged from the outlet of the condenser 2 passes through the drying filter 3, the refrigerant first passes through the first capillary tube 8, which can block most of the gaseous refrigerant from being sucked into the air intake of the compressor 1. Then, the refrigerant passes through the second capillary tube 9. Since the second capillary tube 9 has a smaller diameter and a longer length, its pressure drop is greater, which can further effectively block the gaseous refrigerant from being sucked into the air intake of the compressor 1. This can effectively solve the cooling capacity loss caused by the liquid injection branch in the prior art, thereby improving the cooling effect of the refrigeration unit, reducing power consumption, and increasing the performance coefficient. On the other hand, the refrigeration unit of the preferred technical solution of this embodiment can control the liquid injection amount of the liquid injection branch through the first capillary tube 8 and the second capillary tube 9, which not only improves the reliability of the refrigeration unit, but also prevents the problem of liquid in the compressor 1 suction caused by excessive liquid injection, thereby extending the service life of the compressor 1.

[0048] According to a preferred embodiment, the liquid injection branch further includes a first control valve 10, which is connected in series with the first capillary tube 8 and the second capillary tube 9. Figure 2As shown. Preferably, the first control valve 10 is a solenoid valve. In the refrigeration unit of the preferred technical solution of this embodiment, the liquid spray branch also includes a first control valve 10, and the opening and closing of the liquid spray branch can be controlled by opening and closing the first control valve 10. Specifically, when the liquid spray branch is closed, the cooling loss caused by the liquid spray branch can be completely avoided, thereby improving the cooling effect of the refrigeration unit, reducing power consumption, and increasing the performance coefficient; when the liquid spray branch is opened, compared with the existing refrigeration unit, the amount of refrigerant entering the compressor 1 through the liquid spray branch can be reduced through the blocking effect of at least two stages of throttling and pressure reducing components, thereby reducing the cooling loss of the refrigeration unit caused by liquid spray, thereby improving the cooling effect of the refrigeration unit, reducing power consumption, and increasing the performance coefficient.

[0049] According to a preferred embodiment, the refrigeration unit further includes a first bypass branch, which is arranged in parallel with the throttling and pressure reducing component close to the compressor 1, and a second control valve 11 is arranged on the first bypass branch. Figure 2 As shown. Preferably, the second control valve 11 is a solenoid valve. The refrigeration unit of the preferred technical solution of this embodiment can control the opening and closing of the first bypass branch by opening and closing the second control valve 11. Specifically, when the exhaust temperature of the compressor 1 is too high, the first bypass branch is opened. Since the first bypass branch is arranged in parallel with the throttling and pressure reducing component close to the side of the compressor 1, a large amount of liquid is sprayed to the compressor 1 through the first bypass branch, which can reduce the exhaust temperature of the compressor 1 to maintain the normal operation of the compressor 1; after the exhaust temperature of the compressor 1 is reduced to a preset range, the first bypass branch is closed to avoid the cooling loss of the refrigeration unit caused by the liquid spraying from the first bypass branch.

[0050] According to a preferred embodiment, the refrigeration unit further includes a second bypass branch, which is arranged in parallel with the liquid injection branch, and a third control valve 12 is arranged on the second bypass branch. Figure 2 As shown. Preferably, the third control valve 12 is a solenoid valve. The refrigeration unit of the preferred technical solution of this embodiment can control the opening and closing of the second bypass branch by opening and closing the third control valve 12. Specifically, when the pressure ratio of the refrigeration unit exceeds the operating range of the unit, or the exhaust parameters of the compressor 1 (including exhaust temperature and / or exhaust pressure) exceed the preset exhaust parameters, the first bypass branch and the second bypass branch are opened, and the high-pressure liquid refrigerant on the condenser 2 side can be unloaded into the gas-liquid separator 5, thereby reducing the pressure ratio of the refrigeration unit or reducing the exhaust parameters of the compressor 1 to ensure the reliability and service life of the refrigeration unit, and avoid the refrigeration unit from being shut down for protection or frequently started and stopped, resulting in large fluctuations in indoor temperature, unstable warehouse temperature, and affecting the storage of goods. It can be seen that the refrigeration unit of the preferred technical solution of this embodiment can improve the adaptability of the refrigeration unit by setting the second bypass branch, so that the refrigeration unit can operate stably under high pressure ratio conditions.

[0051] Example 2

[0052] This embodiment describes the air conditioning system of the present invention in detail.

[0053] The air conditioning system of this embodiment includes the refrigeration unit of any one of the technical solutions in Example 1. Preferably, the air conditioning system of this embodiment is an air conditioning system for a cold storage. The remaining components of the air conditioning system of this embodiment may be the same as those in the prior art and will not be described in detail here.

[0054] The air-conditioning system of this embodiment includes a refrigeration unit according to any one of the technical solutions in Example 1. Since the refrigeration effect of the refrigeration unit is improved, the power consumption is reduced, and the performance coefficient is increased, the refrigeration capacity of the air-conditioning system of this embodiment can be improved, the power consumption is reduced, and the performance coefficient is increased.

[0055] Example 3

[0056] This embodiment describes in detail the control method of the refrigeration unit of the present invention.

[0057] Figure 3 FIG. 1 is a flow chart showing the control method of the refrigeration unit according to the present embodiment. Figure 3 As shown, the control method of the refrigeration unit of any technical solution in Example 1 includes the following steps:

[0058] Step 1: Get the exhaust temperature of compressor 1.

[0059] Step 2: Compare the exhaust gas temperature of the compressor 1 with a first preset exhaust gas temperature.

[0060] Step 3: When T1 ≥ T 01 When T1<T 01 When the liquid injection branch is closed, T1 is the exhaust temperature of compressor 1, T 01 The first preset exhaust temperature is preferably 110°C.

[0061] The control method of the refrigeration unit of any technical solution in embodiment 1 is to obtain the exhaust temperature of the compressor 1, compare the exhaust temperature of the compressor 1 with the first preset exhaust temperature, and when T1≥T 01 When T1<T 01 When the liquid injection branch is closed, the step of controlling the closing of the liquid injection branch can not only maintain the normal operation of the compressor 1, but also reduce the amount of refrigerant entering the compressor 1 through the liquid injection branch, thereby reducing the cooling loss of the refrigeration unit caused by the liquid injection, and further improving the cooling effect of the refrigeration unit, reducing power consumption and increasing the performance coefficient.

[0062] According to a preferred embodiment, when the liquid injection branch is opened, the following steps are also included:

[0063] Get the exhaust temperature of compressor 1.

[0064] The exhaust gas temperature of the compressor 1 is compared with a second preset exhaust gas temperature.

[0065] When T1≥T 02 When T1<T 02 When the first bypass branch is closed, T 02 >T 01 , T1 is the exhaust temperature of compressor 1, T 02 The second preset exhaust temperature is preferably 115°C.

[0066] The preferred technical solution of the present embodiment is a control method for a refrigeration unit. When the liquid spray branch is opened, the exhaust temperature of the compressor 1 still does not decrease, but instead increases to a temperature higher than the second preset exhaust temperature. At this time, the first bypass branch is opened. Since the first bypass branch is arranged in parallel with the throttling and pressure reducing component close to the side of the compressor 1, a large amount of liquid is sprayed to the compressor 1 through the first bypass branch, thereby reducing the exhaust temperature of the compressor 1 to maintain the normal operation of the compressor 1; after the exhaust temperature of the compressor 1 is reduced to a preset range, the first bypass branch is closed to avoid the cooling loss of the refrigeration unit caused by the liquid spraying from the first bypass branch.

[0067] According to a preferred embodiment, the control method of the refrigeration unit further includes the following steps:

[0068] Obtain the pressure ratio of the refrigeration unit or the exhaust parameters of the compressor 1. Preferably, the exhaust parameters of the compressor 1 include the exhaust pressure of the compressor 1 and / or the exhaust temperature of the compressor 1.

[0069] The pressure ratio of the refrigeration unit is compared with a preset pressure ratio of the refrigeration unit, or the exhaust parameter of the compressor 1 is compared with a preset exhaust parameter.

[0070] When the pressure ratio of the refrigeration unit exceeds the preset pressure ratio of the refrigeration unit, or the exhaust parameter of compressor 1 exceeds the preset exhaust parameter, the first bypass branch and the second bypass branch are controlled to open; when the pressure ratio of the refrigeration unit is less than the preset pressure ratio of the refrigeration unit, or the exhaust parameter of compressor 1 is less than the preset exhaust parameter, the first bypass branch is controlled to open and the second bypass branch is closed.

[0071] The control method of the refrigeration unit of the preferred technical solution of this embodiment is that when the pressure ratio of the refrigeration unit exceeds the preset pressure ratio of the refrigeration unit, or the exhaust parameters of the compressor 1 exceed the preset exhaust parameters, the first bypass branch and the second bypass branch are controlled to be opened, and the high-pressure liquid refrigerant on the side of the condenser 2 can be unloaded to the gas-liquid separator 5, thereby reducing the pressure ratio of the refrigeration unit or reducing the exhaust parameters of the compressor 1, so as to ensure the reliability and service life of the refrigeration unit, avoid the refrigeration unit from being shut down for protection or frequently started and stopped, resulting in large fluctuations in indoor temperature, unstable storage temperature, and affecting the storage of goods. It can be seen that the control method of the refrigeration unit of the preferred technical solution of this embodiment can improve the adaptability of the refrigeration unit by controlling the opening and closing of the first bypass branch and the second bypass branch, so that the refrigeration unit can operate stably under high-pressure ratio conditions.

[0072] The control method of the refrigeration unit of the preferred technical solution of this embodiment is not limited to controlling the opening and closing of the first bypass branch and the second bypass branch based on the pressure ratio of the refrigeration unit or the exhaust parameters of the compressor 1, but can also control the opening and closing of the first bypass branch and the second bypass branch based on the actual load demand of the refrigeration unit.

[0073] In the description of the present invention, it should be noted that, unless otherwise specified, "plurality" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific direction, be constructed, or operate in a specific direction, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0074] It should also be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention depending on the specific circumstances.

[0075] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A refrigeration unit, characterized in that: It includes refrigeration circuit and liquid injection branch, among which, The refrigeration circuit is formed by sequentially connecting the exhaust port of the compressor (1), the condenser (2), the evaporator (4), the gas-liquid separator (5) and the air intake of the compressor (1); The liquid spray branch is arranged in parallel with the evaporator (4) and the gas-liquid separator (5), and at least two stages of throttling and pressure reducing components are connected in series on the liquid spray branch, and the pressure drop of the throttling and pressure reducing component on the side close to the compressor (1) is greater than the pressure drop of the throttling and pressure reducing component on the side close to the condenser (2); The liquid injection branch comprises a first capillary tube (8) and a second capillary tube (9), the first capillary tube (8) and the second capillary tube (9) are connected in series, the other end of the first capillary tube (8) is connected to the condenser (2), and the other end of the second capillary tube (9) is connected to the suction port of the compressor (1); The liquid spray branch further comprises a first control valve (10), wherein the first control valve (10) is connected in series with the first capillary tube (8) and the second capillary tube (9); It also includes a first bypass branch, the first bypass branch is arranged in parallel with the throttling and pressure reducing component close to one side of the compressor (1), and a second control valve (11) is arranged on the first bypass branch; It also includes a second bypass branch, which is arranged in parallel with the liquid injection branch, and a third control valve (12) is arranged on the second bypass branch.

2. The refrigeration unit according to claim 1, characterized in that: The diameter of the first capillary tube (8) is 2.6-2.8 mm, and the length is 25-35 mm; the diameter of the second capillary tube (9) is 2.3-2.5 mm, and the length is 55-65 mm.

3. An air conditioning system, characterized in that: Including the refrigeration unit according to claim 1 or 2.

4. A control method for a refrigeration unit according to claim 1 or 2, characterized in that: The steps include: Obtain the exhaust temperature of the compressor (1); comparing the exhaust temperature of the compressor (1) with a first preset exhaust temperature; When T1≥T 01 When T1<T 01 When the injection branch is closed, T1 is the exhaust temperature of the compressor (1), T 01 It is the first preset exhaust temperature.

5. The control method of the refrigeration unit according to claim 4, characterized in that: When the liquid spray branch is opened, the following steps are also included: Obtain the exhaust temperature of the compressor (1); comparing the exhaust gas temperature of the compressor (1) with a second preset exhaust gas temperature; When T1≥T 02 When T1<T 02 When the first bypass branch is closed, T 02 >T 01 , T1 is the exhaust temperature of compressor (1), T 02 is the second preset exhaust temperature.

6. The control method for a refrigeration unit according to claim 4 or 5, characterized in that: The following steps are also included: Obtaining the pressure ratio of the refrigeration unit or the exhaust parameters of the compressor (1); Comparing the pressure ratio of the refrigeration unit with a preset pressure ratio of the refrigeration unit, or comparing the exhaust parameters of the compressor (1) with preset exhaust parameters; When the pressure ratio of the refrigeration unit exceeds a preset pressure ratio of the refrigeration unit, or the exhaust parameter of the compressor (1) exceeds a preset exhaust parameter, the first bypass branch and the second bypass branch are controlled to open; When the pressure ratio of the refrigeration unit is less than the preset pressure ratio of the refrigeration unit, or the exhaust parameter of the compressor (1) is less than the preset exhaust parameter, the first bypass branch is controlled to open and the second bypass branch is controlled to close.

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