Ejector refrigeration system and control method

Abstract

The present invention relates to an ejector refrigeration system and a control method, belonging to the technical field of ejector refrigeration systems, and solves the problem in the prior art that when the condensation temperature is higher or lower than the designed condensation temperature, the ejection performance of the ejector will be affected. The ejector refrigeration system includes a compressor, a condenser, an ejector, an evaporator and a separator. The outlet of the condenser is communicated with the main flow inlet of the ejector through a first branch. The outlet of the ejector is communicated with the inlet of the separator. The liquid outlet of the separator is communicated with the first inlet of the evaporator through a first throttling component. The first outlet of the evaporator is communicated with the secondary flow inlet of the ejector. The gas outlet of the separator is connected to the air inlet of the compressor. The outlet of the condenser is successively communicated with the second inlet of the evaporator through a second branch and a second throttling component. The exhaust port of the compressor is communicated with the third inlet of the evaporator through a third branch. The opening and closing of the first branch, the second branch and the third branch can be controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of ejector refrigeration systems, and particularly relates to an ejector refrigeration system and a control method therefor. Background Art

[0002] The refrigeration performance of a compression refrigeration system with an ejector is closely related to the operating conditions of the system. This is because the ejector coefficient decreases as the evaporation temperature increases. At this time, the flow rate ratio of the entrained fluid to the working fluid increases, and the compression ability of the ejector for the entrained fluid decreases. The increase in the coefficient of performance of refrigeration is also relatively smaller compared to traditional refrigeration systems.

[0003] When the condensation temperature is relatively low, the flow rate of the working fluid is small, and the ejector effect cannot be fully exerted. When the condensation temperature increases, the flow rate ratio of the entrained fluid to the working fluid decreases.

[0004] However, when the condensation temperature rises to a certain extent and reaches the ejector coefficient under the design conditions, the ejector coefficient no longer increases. Therefore, the operating parameters of the system, especially the magnitude of the condensation temperature, have a significant impact on the compression refrigeration system with an ejector. Sometimes, the refrigeration capacity of the system is even lower than that of traditional refrigeration systems. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an ejector refrigeration system and a control method therefor, so as to solve the technical problem in the prior art that when the condensation temperature is seriously higher or lower than the designed condensation temperature, it will affect the ejector performance, thereby reducing the refrigeration capacity of the system.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] According to the first aspect of the embodiments of the present invention, an ejector refrigeration system is provided, including a compressor, a condenser, an ejector, an evaporator, and a separator, wherein:

[0008] The outlet of the condenser is connected to the main flow inlet of the ejector through a first branch; the outlet of the ejector is connected to the inlet of the separator; the liquid outlet of the separator is connected to the first inlet of the evaporator through a first throttling component; the first outlet of the evaporator is connected to the secondary flow inlet of the ejector; the gas outlet of the separator is connected to the intake port of the compressor;

[0009] The outlet of the condenser is sequentially connected to the second throttling component and the second inlet of the evaporator through a second branch; the exhaust port of the compressor is connected to the third inlet of the evaporator through a third branch, and the on-off of the first branch, the second branch, and the third branch can be controlled.

[0010] As an optional implementation manner of the present invention, the air inlet of the compressor is connected to the second outlet of the evaporator through a fourth branch, and the on-off of the fourth branch can be controlled.

[0011] As an optional implementation manner of the present invention, the ejector refrigeration system further includes a first control valve provided on the first branch, a second control valve provided on the second branch, a third control valve provided on the third branch, and a fourth control valve provided on the fourth branch. Wherein, the on-off of the corresponding branches is controlled by the first control valve, the second control valve, the third control valve, and the fourth control valve respectively.

[0012] As an optional implementation manner of the present invention, the first control valve, the second control valve, the third control valve, and the fourth control valve are all one-way solenoid valves, wherein:

[0013] The inlet ends of the first control valve and the second control valve are respectively connected to the outlet end of the condenser. The outlet end of the first control valve is connected to the main flow inlet end of the ejector. The outlet end of the second control valve is connected with the second throttling component. The outlet end of the third control valve is connected to the third inlet end of the evaporator. The outlet end of the fourth control valve is connected to the air inlet end of the compressor.

[0014] As an optional implementation manner of the present invention, a flow rate regulating component is further provided on the third branch, and the refrigerant flow rate entering the evaporator through the exhaust port of the compressor is regulated by the flow rate regulating component.

[0015] As an optional implementation manner of the present invention, a temperature detection part is provided at the outlet of the condenser for detecting the refrigerant temperature at the outlet of the condenser.

[0016] As an optional implementation manner of the present invention, a working fluid flow rate detection part is provided on the first branch between the outlet of the condenser and the main flow inlet of the ejector, and an entrained fluid flow rate detection part is provided on the connecting pipeline between the outlet of the evaporator and the secondary flow inlet of the ejector.

[0017] As an optional implementation manner of the present invention, both the first throttling component and the second throttling component are electronic expansion valves.

[0018] According to the second aspect of the embodiments of the present invention, a control method for an ejector refrigeration system is provided, which is used to control any one of the above-mentioned ejector refrigeration systems. The method includes:

[0019] Obtain the condenser outlet temperature and the injection coefficient during the operation of the ejector refrigeration system;

[0020] Compare the condenser outlet temperature with a preset condensation temperature and the injection coefficient with a preset injection coefficient;

[0021] Control the on / off states of the first branch, the second branch, the third branch, and the fourth branch according to the comparison results.

[0022] As an optional implementation manner of the present invention, the obtaining of the condenser outlet temperature and the injection coefficient during the operation of the ejector refrigeration system includes:

[0023] Detect the condenser outlet temperature at the outlet of the condenser;

[0024] Detect the working fluid flow rate in the first branch between the outlet of the condenser and the main flow inlet of the ejector;

[0025] Detect the entrained fluid flow rate in the connecting pipeline between the outlet of the evaporator and the secondary flow inlet of the ejector;

[0026] Calculate the ratio of the entrained fluid flow rate to the working fluid flow rate to obtain the injection coefficient.

[0027] As an optional implementation manner of the present invention, the controlling of the on / off states of the first branch, the second branch, the third branch, and the fourth branch according to the comparison results includes:

[0028] Determine the operation mode of the ejector refrigeration system according to the comparison results;

[0029] Control the on / off states of the first branch, the second branch, and the third branch according to the operation mode;

[0030] Wherein, the operation mode includes a first operation mode, a second operation mode, a third operation mode, and a fourth operation mode. The first operation mode is to turn on the first branch and turn off the second branch, the third branch, and the fourth branch; the second operation mode is to turn on the first branch and the second branch and turn off the third branch and the fourth branch; the third operation mode is to turn on the first branch and the third branch and turn off the second branch and the fourth branch; the fourth operation mode is to turn on the second branch and the fourth branch and turn off the first branch and the third branch.

[0031] As an optional implementation manner of the present invention, a first control valve is provided on the first branch, a second control valve is provided on the second branch, a third control valve is provided on the third branch, and a fourth control valve is provided on the fourth branch. The operation modes are respectively:

[0032] First operation mode, control the first control valve and the first throttling component to open, and the second control valve, the second throttling component, the third control valve, and the fourth control valve to close;

[0033] The second operating mode is to control the first control valve, the first throttling component, the second control valve and the second throttling component to open, and the third control valve and the fourth control valve to close;

[0034] The third operating mode is to control the first control valve, the first throttling component and the third control valve to open, and the second control valve, the second throttling component and the fourth control valve to close;

[0035] The fourth operating mode is to control the fourth control valve, the second control valve and the second throttling component to open, and the first control valve, the first throttling component and the third control valve to close.

[0036] As an optional implementation manner of the present invention, the preset condensation temperature includes a first preset condensation temperature T c1 and a second preset condensation temperature T c2 , and the preset injection coefficient includes a first preset injection coefficient μ set1 and a second preset injection coefficient μ set2 , where T c2 < T c1 , μ set2 < μ set1 .

[0037] As an optional implementation manner of the present invention, the comparing the condenser outlet temperature with the preset condensation temperature and the injection coefficient with the preset injection coefficient includes:

[0038] Comparing the condenser outlet temperature T with the first preset condensation temperature T c1 and the second preset condensation temperature T c2 ;

[0039] Comparing the injection coefficient μ with the first preset injection coefficient μ set1 and the second preset injection coefficient μ set2 .

[0040] As an optional implementation manner of the present invention, the determining the operating mode of the ejector refrigeration system according to the comparison result includes:

[0041] When T > T c1 and μ < μ set1 , it is determined that the ejector refrigeration system operates in the third operating mode;

[0042] When T c2 < T < T c1 and μ < μ set2 , it is determined that the ejector refrigeration system operates in the second operating mode;

[0043] T = T c1 When this occurs, it is determined that the ejector refrigeration system operates in the first operating mode;

[0044] T ≤ T c2 When this occurs, it is determined that the ejector refrigeration system operates in the fourth operating mode.

[0045] As an optional implementation manner of the present invention, when the ejector refrigeration system operates in the third operating mode, the method further includes:

[0046] Obtain the actual operating opening X of the second throttling component;

[0047] Judge whether the actual operating opening reaches the preset opening α;

[0048] If X < α, it is determined to continue to increase the opening of the first throttling component;

[0049] If X ≥ α, it is determined to stop continuing to increase the opening of the first throttling component.

[0050] The ejector refrigeration system provided by the present invention adds a second branch and a third branch as bypass branches on the basis of the first branch. Its first branch is the traditional ejector refrigeration mode, and the refrigerant flows through the compressor, condenser, ejector main flow inlet, ejector outlet, and separator inlet in sequence; thereafter, the refrigerant flowing out from the separator gas outlet flows back into the compressor; the refrigerant flowing out from the separator liquid outlet passes through the first throttling component and then flows through the evaporator and then flows to the ejector secondary flow inlet. By introducing the bypass third branch, when the condensation temperature at the condenser outlet is relatively high, part of the high-temperature and high-pressure refrigerant can be introduced into the evaporator through the third branch to reduce the condensation temperature; when the condensation temperature is relatively low, part of the high-temperature and high-pressure refrigerant coming out of the condenser can be made to flow through the second throttling component by introducing the second branch with the second throttling component, and mix with the fluid coming out after throttling by the first throttling component in the evaporator. After mixing, it becomes the ejector fluid. At this time, it is equivalent to increasing the flow rate of the ejector fluid to increase the evaporation temperature, thereby correspondingly increasing the condensation temperature. The present invention enables the condensation temperature of the unit operation to be closer to the designed condensation temperature of the ejector through the switching between each branch, so that the ejector can play a greater role, ensure the reliability of the unit operation, and better meet the refrigeration capacity requirement of the unit.

[0051] In addition, a fourth branch is added in the present invention. When the condensation temperature at the outlet of the condenser is low to a certain extent, the refrigerating capacity of ejector refrigeration will be lower than that of the traditional mode (the refrigeration mode without an ejector). At this time, the ejector refrigeration operation is no longer used, and the traditional mode refrigeration is switched to. That is, the fluid on the high-temperature side flows from the compressor exhaust port to the condenser, enters the second branch, is throttled and depressurized by the second throttling component, then flows to the evaporator, and finally returns to the compressor, avoiding the situation of low refrigerating capacity and further ensuring the refrigerating capacity of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0053] Figure 1 is a schematic diagram of the principle structure of the ejector refrigeration system provided by the embodiment of the present invention;

[0054] Figure 2 is a schematic flowchart of the control method of the ejector refrigeration system provided by the embodiment of the present invention;

[0055] Figure 3 is a flowchart of an embodiment of the control method of the ejector refrigeration system provided by the embodiment of the present invention;

[0056] Figure 4 is a flowchart of the adjustment of the first throttling component in the third operating mode provided by the embodiment of the present invention.

[0057] In the figure: 1. Compressor; 2. Condenser; 3. Ejector; 4. Evaporator; 5. Separator; 6. First control valve; 7. First throttling component; 8. Second control valve; 9. Second throttling component; 10. Third control valve; 11. Flow regulating component; 12. Fourth control valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope protected by the present invention.

[0059] See Figure 1, the present invention provides an ejector refrigeration system, including a compressor 1, a condenser 2, an ejector 3, an evaporator 4 and a separator 5. The ejector 3 has a main flow inlet connected to the condenser 2, and it also has a secondary flow inlet and an outlet; the separator 5 has an inlet connected to the outlet of the ejector 3, a liquid outlet connected to a first throttling element, and a gas outlet connected to the intake port of the compressor 1.

[0060] Among them, the outlet of the condenser 2 is connected to the main flow inlet of the ejector 3 through a first branch. The outlet of the ejector 3 is connected to the inlet of the separator 5. The liquid outlet of the separator 5 is connected to the first inlet of the evaporator 4 through a first throttling component 7. The first outlet of the evaporator 4 is connected to the secondary flow inlet of the ejector 3. The gas outlet of the separator 5 is connected to the intake port of the compressor 1. The above is a relatively conventional refrigeration mode of the ejector 3. More specifically, in the above mode, the refrigerant flows through the compressor 1, the condenser 2, the main flow inlet of the ejector 3, the outlet of the ejector 3, and the inlet of the separator 5 in sequence; thereafter, it flows back to the compressor 1 from the gas outlet of the separator 5; the refrigerant flowing out from the liquid outlet of the separator 5 is throttled by the first throttling component 7, then flows through the evaporator 4, and flows to the secondary flow inlet of the ejector 3 through the first outlet of the evaporator 4.

[0061] The ejector refrigeration system provided by the embodiment of the present invention adds a second branch and a third branch as bypass branches on the basis of the first branch. The outlet of the condenser 2 is connected to the second inlet of the evaporator 4 through the second branch in sequence; the exhaust port of the compressor 1 is connected to the third inlet of the evaporator 4 through the third branch. The on-off of the first branch, the second branch and the third branch can be controlled.

[0062] By introducing the bypass third branch, when the condensation temperature at the outlet of the condenser 2 is relatively high, part of the high-temperature and high-pressure refrigerant can be introduced into the evaporator 4 through the third branch, so that the condensation temperature is reduced; when the condensation temperature is relatively low, part of the high-temperature and high-pressure refrigerant coming out of the condenser 2 can be made to flow through the second throttling component 9 through the introduced second branch with the second throttling component 9, and mix with the fluid coming out after throttling from the first throttling component 7 in the evaporator 4. After mixing, it becomes the ejector fluid. At this time, it is equivalent to increasing the flow rate of the ejector fluid to increase the evaporation temperature, thereby correspondingly increasing the condensation temperature. The present invention makes the condensation temperature of the unit operation closer to the designed condensation temperature of the ejector 3 by switching between various branches, so that the ejector 3 can play a greater role, ensure the reliability of the unit operation, and better meet the refrigeration capacity requirement of the unit.

[0063] In addition, a fourth branch is added to the ejector refrigeration system in this embodiment. The intake port of the compressor 1 is connected to the second outlet of the evaporator 4 through the fourth branch, and the on-off of the fourth branch can be controlled. When the condensation temperature at the outlet of the condenser 2 is low to a certain extent, the refrigeration capacity of ejector refrigeration will be lower than that of the traditional mode (the refrigeration mode without the ejector 3). At this time, it no longer operates in ejector refrigeration mode and switches to traditional mode refrigeration, that is, the fluid on the high-temperature side flows from the exhaust port of the compressor 1 to the condenser 2, flows through the second throttle component 9 after entering the second branch for throttling and pressure reduction, then flows to the evaporator 4, and finally returns to the compressor 1, avoiding the situation of low refrigeration capacity and further ensuring the refrigeration capacity of the unit.

[0064] To achieve the on-off control of the first branch, second branch, third branch and fourth branch in the foregoing embodiment, in this embodiment, each branch can be controlled to be on or off by a separate switching valve. As an example, the ejector refrigeration system further includes a first control valve 6 provided on the first branch, a second control valve 8 provided on the second branch, a third control valve 10 provided on the third branch, and a fourth control valve 12 provided on the fourth branch. Among them, the first control valve 6, the second control valve 8, the third control valve 10 and the fourth control valve respectively control the on-off of the corresponding branch.

[0065] Optionally, the first control valve 6, the second control valve 8, the third control valve 10 and the fourth control valve 12 are all one-way solenoid valves, the control principle and control logic settings are extremely simple, and the control stability of the flow path on-off is high.

[0066] Specifically, the inlet ends of the first control valve 6 and the second control valve 8 are respectively connected to the outlet end of the condenser 2. The outlet end of the first control valve 6 is connected to the main flow inlet end of the ejector 3. The outlet end of the second control valve 8 is connected with a second throttle component 9. The inlet end of the third control valve 10 is connected to the exhaust port end of the compressor 1. The outlet end of the third control valve 10 is connected to the third inlet end of the evaporator 4. The inlet end of the fourth control valve 12 is connected to the second outlet end of the evaporator 4. The outlet end of the fourth control valve 12 is connected to the intake port end of the compressor 1.

[0067] As an optional implementation manner, both the first throttle component 7 and the second throttle component 9 are electronic expansion valves. A flow regulating component 11 is also provided on the third branch, and the refrigerant flow rate entering the evaporator 4 through the exhaust port of the compressor 1 is regulated by the flow regulating component.

[0068] In this embodiment, a temperature detection unit is provided at the outlet of the condenser 2. The temperature detection unit is a temperature sensor and is used to detect the refrigerant temperature at the outlet of the condenser 2. A working fluid flow rate detection unit is provided on the first branch between the outlet of the condenser 2 and the main flow inlet of the ejector 3, and an entrained fluid flow rate detection unit is provided on the connecting pipeline between the outlet of the evaporator 4 and the secondary flow inlet of the ejector 3. The working fluid flow rate detection unit and the entrained fluid flow rate detection unit are flow meters. The working fluid flow rate of the ejector refrigeration system is measured by the working fluid flow rate detection unit, and the entrained fluid flow rate of the ejector refrigeration system is measured by the entrained fluid flow rate detection unit. The ejection coefficient during the operation of the ejector refrigeration system can be obtained based on the entrained fluid flow rate and the working fluid flow rate. Different branches can be switched on according to the refrigerant temperature at the outlet of the condenser 2 and the ejection coefficient during the system operation.

[0069] To more clearly illustrate the regulation of the system loop of the ejector 3 in the technical solution of the present invention, the regulation of the system loop of the ejector 3 is defined as the following multiple working modes and described by way of examples:

[0070] First operating mode: Control the first control valve 6 and the first throttling component 7 to open, and the second control valve 8, the second throttling component 9, the third control valve 10 and the fourth control valve 12 to close; The refrigerant flows through the compressor 1, the condenser 2, the main flow inlet of the ejector 3, the outlet of the ejector 3, and the inlet of the separator 5 in sequence; Thereafter, it flows back to the compressor 1 from the gas outlet of the separator 5; The refrigerant flowing out from the liquid outlet of the separator 5 is throttled by the first throttling component 7, then flows through the evaporator 4, and flows to the secondary flow inlet of the ejector 3 through the first outlet of the evaporator 4.

[0071] Second operating mode: Control the first control valve 6, the first throttling component 7, the second control valve 8 and the second throttling component 9 to open, and the third control valve 10 and the fourth control valve 12 to close; That is, on the basis of the first operating mode, the second branch is turned on. Part of the high-temperature and high-pressure refrigerant coming out of the condenser 2 flows through the second control valve 8 and the second throttling component 9, and mixes with the fluid coming out after throttling by the first throttling component 7 in the evaporator 4. After mixing, it becomes the entrained fluid and enters the secondary flow inlet of the ejector 3.

[0072] Third operating mode: Control the first control valve 6, the first throttling component 7 and the third control valve 10 to open, and the second control valve 8, the second throttling component 9 and the fourth control valve 12 to close; That is, on the basis of the first operating mode, the third branch is turned on. Part of the high-temperature and high-pressure refrigerant coming out of the exhaust port of the compressor 1 is introduced into the evaporator 4 through the flow regulating component 11 and the third control valve 10.

[0073] Fourth operating mode: control the fourth control valve 12, the second control valve 8 and the second throttling component 9 to open, and the first control valve 6, the first throttling component 7 and the third control valve 10 to close. That is, close the first branch and the third branch, and conduct the second branch and the fourth branch. The fluid on the high-temperature side flows from the exhaust port of the compressor 1 to the condenser 2, enters the second branch, is throttled and depressurized by the second throttling component 9, then flows to the evaporator 4, and finally returns to the intake port of the compressor 1 through the fourth branch.

[0074] Based on a general inventive concept, an embodiment of the present invention further provides a control method for an ejector refrigeration system. Figure 2 It is a schematic flowchart provided by an embodiment of the control method of the ejector refrigeration system of the present invention. Refer to Figure 2 The control method of the ejector refrigeration system of the present invention can be applied to the ejector refrigeration system described in any of the above embodiments, and may include the following steps:

[0075] Step S21: Obtain the condenser outlet temperature and the injection coefficient during the operation of the ejector refrigeration system;

[0076] Step S22: Compare the condenser outlet temperature with the preset condensation temperature and the injection coefficient with the preset injection coefficient;

[0077] Step S23: Control the on / off of the first branch, the second branch, the third branch and the fourth branch according to the comparison result.

[0078] Optionally, in the above embodiment of the present invention, in step S21, obtaining the condenser outlet temperature and the injection coefficient during the operation of the ejector refrigeration system includes:

[0079] Step S211: Detect the condenser outlet temperature T at the outlet of the condenser 2; specifically, detect the refrigerant temperature at the outlet of the condenser 2 through a temperature sensor arranged at the outlet of the condenser 2, that is, the condenser outlet temperature;

[0080] Step S212: Detect the working fluid flow rate G1 on the first branch between the outlet of the condenser 2 and the main flow inlet of the ejector 3; specifically, it is detected by a working fluid flow rate detection unit arranged on the first branch between the outlet of the condenser 2 and the main flow inlet of the ejector 3;

[0081] Step S213: Detect the entrained fluid flow rate G2 on the connecting pipeline between the outlet of the evaporator 4 and the secondary flow inlet of the ejector 3; specifically, it is detected by an entrained fluid flow rate detection unit arranged on the connecting pipeline between the outlet of the evaporator 4 and the secondary flow inlet of the ejector 3;

[0082] Step S214: Calculate the ratio G2 / G1 of the entrained fluid flow rate to the working fluid flow rate to obtain the injection coefficient.

[0083] Optionally, in the above embodiments of the present invention, in step S23, according to the comparison result, controlling the on / off of the first branch, the second branch, the third branch, and the fourth branch includes:

[0084] Step S231, determining the operating mode of the ejector refrigeration system according to the comparison result;

[0085] Step S232, controlling the on / off of the first branch, the second branch, and the third branch according to the operating mode;

[0086] Among them, the operating modes include a first operating mode, a second operating mode, a third operating mode, and a fourth operating mode. The first operating mode is to turn on the first branch and turn off the second branch, the third branch, and the fourth branch; the second operating mode is to turn on the first branch and the second branch and turn off the third branch and the fourth branch; the third operating mode is to turn on the first branch and the third branch and turn off the second branch and the fourth branch; the fourth operating mode is to turn on the second branch and the fourth branch and turn off the first branch and the third branch.

[0087] Optionally, a first control valve 6 is provided on the first branch, a second control valve 8 is provided on the second branch, a third control valve 10 is provided on the third branch, and a fourth control valve 12 is provided on the fourth branch. The operating modes in this embodiment are respectively:

[0088] The first operating mode is to control the first control valve 6 and the first throttling component 7 to open, and the second control valve 8, the second throttling component 9, the third control valve 10, and the fourth control valve 12 to close;

[0089] The second operating mode is to control the first control valve 6, the first throttling component 7, the second control valve 8, and the second throttling component 9 to open, and the third control valve 10 and the fourth control valve 12 to close;

[0090] The third operating mode is to control the first control valve 6, the first throttling component 7, and the third control valve 10 to open, and the second control valve 8, the second throttling component 9, and the fourth control valve 12 to close;

[0091] The fourth operating mode is to control the fourth control valve 12, the second control valve 8, and the second throttling component 9 to open, and the first control valve 6, the first throttling component 7, and the third control valve 10 to close.

[0092] In this embodiment, the above-mentioned preset condensation temperature includes a first preset condensation temperature T c1 and a second preset condensation temperature T c2 , and the preset injection coefficient includes a first preset injection coefficient μ set1 and a second preset injection coefficient μ set2 , where T c2 <Tc1 , μ set2 <μ set1 , preferably, T in this embodiment c2 = T c1 -3.

[0093] In step S22, comparing the condenser outlet temperature with the preset condensation temperature and the injection coefficient with the preset injection coefficient includes:

[0094] Step S221, comparing the condenser outlet temperature T with the first preset condensation temperature T c1 and the second preset condensation temperature T c2 ;

[0095] Step S222, comparing the injection coefficient μ with the first preset injection coefficient μ set1 and the second preset injection coefficient μ set2 ;

[0096] As Figure 3 shown, optionally, in the above embodiments of the present invention, in step S231, according to the comparison result, determining the operation mode of the ejector refrigeration system includes:

[0097] When T > T c1 and μ < μ set1 , it is determined that the ejector refrigeration system operates in the third operation mode;

[0098] When T c2 < T < T c1 and μ < μ set2 , it is determined that the ejector refrigeration system operates in the second operation mode;

[0099] When T = T c1 , it is determined that the ejector refrigeration system operates in the first operation mode;

[0100] When T ≤ T c2 , it is determined that the ejector refrigeration system operates in the fourth operation mode.

[0101] Specifically, when the condenser outlet temperature is higher than the first preset condensation temperature and the injection coefficient is greater than the first preset injection coefficient, it indicates that the condenser outlet temperature is too high and the injection coefficient is too large during the actual operation process. At this time, control the first control valve 6, the first throttling component 7, and the third control valve 10 to open, and the second control valve 8, the second throttling component 9, and the fourth control valve 12 to close. The system operates in the third operation mode. At this time, a small part of the high-temperature and high-pressure gas flows through the third control valve 10 to the evaporator 4. At this time, the condensation temperature decreases, making the condenser outlet temperature as close as possible to the first preset condensation temperature. When the condenser outlet temperature is lower than the first preset condensation temperature and higher than the second preset condensation temperature, and the injection coefficient is small, it indicates that the evaporation temperature is low at this time. In this case, control the first control valve 6, the first throttling component 7, the second control valve 8, and the second throttling component 9 to open, and the third control valve 10 and the fourth control valve 12 to close. The system operates in the second operation mode. A small part of the high-temperature and high-pressure refrigerant flowing out of the condenser 2 flows through the second throttling component 9 and mixes with the fluid flowing out after throttling by the first throttling component 7. After mixing, it becomes the ejector fluid. At this time, it is equivalent to increasing the flow rate of the ejector fluid to increase the evaporation temperature, thereby correspondingly increasing the condenser outlet temperature.

[0102] When the condenser outlet temperature is lower than the second preset condensation temperature, the condenser outlet temperature in this case is low, and the refrigeration capacity of the ejector refrigeration system will be lower than that of the traditional mode. At this time, switch to the fourth operation mode and no longer operate with the ejector 3 for refrigeration (the first operation mode). The fourth operation mode is refrigeration in the traditional mode.

[0103] The law of the influence of the condenser outlet temperature at the outlet of the condenser 2 during the operation of the ejector refrigeration system on the unit capacity and performance: As the condenser outlet temperature increases, the working fluid flow rate of the ejector 3 increases, the injection coefficient decreases, and the refrigeration capacity first increases and then decreases as the condenser outlet temperature increases, and reaches the maximum when the condensation temperature reaches the designed condensation temperature. In this embodiment, the control of the ejector refrigeration system can make the condenser outlet temperature during the system operation closer to the preset condensation temperature of the ejector 3 (i.e., the above-mentioned first preset condensation temperature), so as to better adjust the operation parameters of the system and better exert the performance of the ejector 3.

[0104] See Figure 4 , when the ejector refrigeration system operates in the third operation mode, the method further includes:

[0105] Obtain the actual operation opening X of the second throttling component 9;

[0106] Judge whether the actual operation opening reaches the preset opening α;

[0107] If X < α, it is determined to continue to increase the opening of the first throttling component 7;

[0108] If X≥α, it is determined to stop further increasing the opening degree of the first throttling component 7. At this time, further opening the first throttling component has little effect on increasing the condenser outlet temperature.

[0109] It can be understood that the same or similar parts in the above embodiments can be referred to each other, and the content not detailed in some embodiments can be seen in the same or similar content of other embodiments.

[0110] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. An ejector refrigeration system, characterized in that, It includes a compressor, a condenser, an ejector, an evaporator, and a separator, where: The outlet of the condenser is connected to the main flow inlet of the ejector through a first branch. The outlet of the ejector is connected to the inlet of the separator. The liquid outlet of the separator is connected to the first inlet of the evaporator through a first throttling component. The first outlet of the evaporator is connected to the secondary flow inlet of the ejector. The gas outlet of the separator is connected to the air inlet of the compressor; The outlet of the condenser is connected to the second inlet of the evaporator through a second branch in sequence and a second throttling component. The exhaust port of the compressor is connected to the third inlet of the evaporator through a third branch. The on-off of the first branch, the second branch, and the third branch can be controlled; A temperature detection part is arranged at the outlet of the condenser for detecting the refrigerant temperature at the outlet of the condenser; A working fluid flow detection part is arranged on the first branch between the outlet of the condenser and the main flow inlet of the ejector, and an entrained fluid flow detection part is arranged on the connecting pipeline between the outlet of the evaporator and the secondary flow inlet of the ejector.

2. The ejector refrigeration system according to claim 1, wherein, The air inlet of the compressor is connected to the second outlet of the evaporator through a fourth branch, and the on-off of the fourth branch can be controlled.

3. The ejector refrigeration system according to claim 2, wherein, The ejector refrigeration system further includes a first control valve arranged on the first branch, a second control valve arranged on the second branch, a third control valve arranged on the third branch, and a fourth control valve arranged on the fourth branch. Among them, the on-off of the corresponding branches is controlled by the first control valve, the second control valve, the third control valve, and the fourth control valve respectively.

4. The ejector refrigeration system according to claim 3, characterized in that, The first control valve, the second control valve, the third control valve, and the fourth control valve are all one-way solenoid valves, where: The inlet ends of the first control valve and the second control valve are respectively connected to the outlet end of the condenser. The outlet end of the first control valve is connected to the main flow inlet end of the ejector. The outlet end of the second control valve is connected to the second throttling component. The outlet end of the third control valve is connected to the third inlet end of the evaporator. The outlet end of the fourth control valve is connected to the air inlet end of the compressor.

5. The ejector refrigeration system according to claim 2, wherein A flow regulating component is further arranged on the third branch, and the refrigerant flow rate entering the evaporator through the exhaust port of the compressor is regulated through the flow regulating component.

6. The ejector refrigeration system according to claim 2, characterized in that, Both the first throttling component and the second throttling component are electronic expansion valves.

7. A control method for an ejector refrigeration system, which is used to control the ejector refrigeration system according to any one of claims 2 to 6 above, characterized in that, The method includes: Obtaining the condenser outlet temperature and the injection coefficient during the operation of the ejector refrigeration system; Comparing the condenser outlet temperature with a preset condensation temperature and the injection coefficient with a preset injection coefficient; Controlling the on-off of the first branch, the second branch, the third branch, and the fourth branch according to the comparison result.

8. The control method of the ejector refrigeration system according to claim 7, characterized in that, The obtaining of the condenser outlet temperature and the injection coefficient during the operation of the ejector refrigeration system includes: Detecting the condenser outlet temperature at the outlet of the condenser; Detecting the working fluid flow rate on the first branch between the outlet of the condenser and the main flow inlet of the ejector; Detect the flow rate of the entrained fluid in the connecting pipeline between the outlet of the evaporator and the secondary flow inlet of the ejector; Calculate the ratio of the flow rate of the entrained fluid to the flow rate of the working fluid to obtain the injection coefficient.

9. The control method of the ejector refrigeration system according to claim 7, characterized in that, According to the comparison result, controlling the on / off of the first branch, the second branch, the third branch, and the fourth branch includes: Determine the operating mode of the ejector refrigeration system according to the comparison result; Control the on / off of the first branch, the second branch, and the third branch according to the operating mode; Wherein, the operating mode includes a first operating mode, a second operating mode, a third operating mode, and a fourth operating mode. The first operating mode is to turn on the first branch and turn off the second branch, the third branch, and the fourth branch; the second operating mode is to turn on the first branch and the second branch and turn off the third branch and the fourth branch; the third operating mode is to turn on the first branch and the third branch and turn off the second branch and the fourth branch; the fourth operating mode is to turn on the second branch and the fourth branch and turn off the first branch and the third branch.

10. The control method of the ejector refrigeration system according to claim 9, characterized in that, A first control valve is provided on the first branch, a second control valve is provided on the second branch, a third control valve is provided on the third branch, and a fourth control valve is provided on the fourth branch. The operating modes are respectively: The first operating mode, control the first control valve and the first throttling component to open, and the second control valve, the second throttling component, the third control valve, and the fourth control valve to close; The second operating mode, control the first control valve, the first throttling component, the second control valve, and the second throttling component to open, and the third control valve and the fourth control valve to close; The third operating mode, control the first control valve, the first throttling component, and the third control valve to open, and the second control valve, the second throttling component, and the fourth control valve to close; The fourth operating mode, control the fourth control valve, the second control valve, and the second throttling component to open, and the first control valve, the first throttling component, and the third control valve to close.

11. The control method of the ejector refrigeration system according to claim 9, characterized in that The preset condensation temperature includes a first preset condensation temperature T c1 and a second preset condensation temperature T c2 . The preset injection coefficient includes a first preset injection coefficient μ set1 and a second preset injection coefficient μ set2 . Among them, T c2 <T c1 , and μ set2 <μ set1 .

12. The control method of the ejector refrigeration system according to claim 11, characterized in that The comparison of the condenser outlet temperature with the preset condensation temperature and the injection coefficient with the preset injection coefficient includes: Compare the condenser outlet temperature T with the first preset condensation temperature T c1 and the second preset condensation temperature T c2 ; Compare the injection coefficient μ with the first preset injection coefficient μ set1 and the second preset injection coefficient μ set2 thereby.

13. The control method of the ejector refrigeration system according to claim 9, characterized in that, According to the comparison result, determining the operating mode of the ejector refrigeration system includes: T > T c1 and μ < μ set1 When this occurs, it is determined that the ejector refrigeration system operates in the third operating mode; T c2 <T<T c1 and μ<μ set2 When this occurs, it is determined that the ejector refrigeration system operates in the second operating mode; T = T c1 When it is, it is determined that the ejector refrigeration system operates in the first operating mode; T≤T c2 When it is satisfied, it is determined that the ejector refrigeration system operates in the fourth operating mode.

14. The control method of the ejector refrigeration system according to claim 9, characterized in that, When the ejector refrigeration system operates in the third operating mode, the method further includes: Obtain the actual operating opening X of the second throttling component; Judge whether the actual operating opening reaches the preset opening α; If X < α, determine to continue to increase the opening of the first throttling component; If X ≥ α, determine to stop continuing to increase the opening of the first throttling component.

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