Refrigeration system and control method, device thereof

Abstract

The application discloses a refrigeration system and a control method and device thereof. The system comprises a compressor, a high-temperature side condenser, a low-temperature side condenser, a high-temperature side evaporator, a low-temperature side evaporator, an ejector and an electronic expansion valve arranged on a pipeline between the low-temperature side condenser and the low-temperature side evaporator. The system further comprises a flow regulating valve arranged on a pipeline between the high-temperature side condenser and the ejector. The electronic expansion valve and the flow regulating valve are used to control refrigerant flow of the low-temperature stage and the high-temperature stage respectively, so that water temperature of the high-temperature stage and the low-temperature stage can be independently adjusted. The injection pressure is adjusted by adjusting injection fluid refrigerant flow of the ejector, and the outlet pressure is adjusted by adjusting working fluid flow, so that operating parameters of the ejector are controlled, the injection coefficient is improved, and the ejector can be used to a greater extent on the basis of meeting actual load demand.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refrigeration systems, in particular to a refrigeration system and a control method and device thereof. BACKGROUND

[0002] The structural design of the ejector is selected to be completed under a given working condition, and cannot be changed once completed, and the ejector is more likely to achieve maximum efficiency under the design condition. If the parameters of the working, injection and outlet fluids deviate from the design parameters, the efficiency of the ejector will decrease, and even cannot work.

[0003] Figure 1 is a structural schematic diagram of an evaporation temperature system in the related art, as Figure 1 shown, the existing evaporation temperature system mainly includes: a compressor 1, a high-temperature side condenser 3, a low-temperature side condenser 4, a regenerator 5, a high-temperature side evaporator 6, a low-temperature side evaporator 7, an ejector 8, and an electronic expansion valve 10. The arrow direction represents the direction of the chilled water inlet and outlet, and the direction of the refrigerant is opposite to that of the chilled water. The existing evaporation temperature system only relies on one electronic expansion valve 10 and the structural limitation of the ejector itself to adjust the refrigerant flow of the low-temperature stage and the high-temperature stage, so that the refrigerant flow of the low-temperature stage and the high-temperature stage cannot be independently adjusted, and the water temperature cannot be accurately controlled. There is also a problem that the actual operating parameters of the ejector deviate from the design parameters, and the injection coefficient is low.

[0004] In view of the problem that the refrigerant flow of the high-temperature stage and the low-temperature stage of the ejector in the prior art cannot be independently adjusted, no effective solution has been proposed so far. SUMMARY

[0005] The present application provides a refrigeration system and a control method and device thereof to solve the problem that the refrigerant flow of the high-temperature stage and the low-temperature stage of the ejector in the prior art cannot be independently adjusted.

[0006] To solve the above technical problems, the present application provides a refrigeration system, wherein the system comprises: a compressor, a high-temperature side condenser, a low-temperature side condenser, a high-temperature side evaporator, a low-temperature side evaporator, an ejector, and an electronic expansion valve located on a pipeline between the low-temperature side condenser and the low-temperature side evaporator, and the system further comprises: a flow regulating valve arranged on a pipeline between the high-temperature side condenser and the ejector.

[0007] Further, the system further comprises: a first electromagnetic valve arranged on a pipeline between the compressor and the high-temperature side condenser.

[0008] Further, the flow regulating valve is used to regulate the flow of high-temperature side refrigerant in the dual-stage refrigeration mode; or the flow regulating valve and the first electromagnetic valve are used to regulate the flow of high-temperature side refrigerant in the dual-stage refrigeration mode; and the electronic expansion valve is used to regulate the flow of low-temperature side refrigerant in the dual-stage refrigeration mode.

[0009] Further, the system further comprises a second electromagnetic valve arranged on a single-stage pipeline, one end of the single-stage pipeline being located between the low-temperature side evaporator and the ejector, and the other end being connected with the refrigerant outlet of the high-temperature side evaporator.

[0010] Further, the second electromagnetic valve is used to open when only the low-temperature side has a cooling load demand, so as to realize the single-stage refrigeration mode; wherein, in the single-stage refrigeration mode, the flow regulating valve and the first electromagnetic valve are closed; and the second electromagnetic valve is used to close when both the low-temperature side and the high-temperature side have a cooling load demand, so as to realize the dual-stage refrigeration mode; wherein, in the dual-stage refrigeration mode, the flow regulating valve and the first electromagnetic valve are opened.

[0011] Further, the second electromagnetic valve is used to cooperate with the electronic expansion valve to regulate the flow of low-temperature side refrigerant in the single-stage refrigeration mode.

[0012] Further, the system further comprises a heat regenerator arranged on a pipeline between the compressor and the high-temperature side evaporator, and also arranged on a pipeline between the low-temperature side condenser and the electronic expansion valve; and the electronic expansion valve is arranged on a pipeline between the heat regenerator and the low-temperature side evaporator.

[0013] The application further provides a control method of a refrigeration system, applied to the above refrigeration system, wherein the method comprises: in the dual-stage refrigeration mode, acquiring an operating parameter of the refrigeration system; and adjusting the opening degrees of a flow regulating valve and an electronic expansion valve according to the operating parameter; wherein the flow regulating valve is used to regulate the flow of high-temperature stage refrigerant, and the electronic expansion valve is used to regulate the flow of low-temperature stage refrigerant.

[0014] Further, the operating parameter at least comprises an outlet refrigerant flow, a water outlet temperature difference, an injection gas pressure and an ejector outlet pressure.

[0015] Further, adjusting the opening degrees of the flow regulating valve and the electronic expansion valve according to the operating parameter comprises: comparing the size of the outlet refrigerant flow with a preset refrigerant flow G out ; wherein the outlet refrigerant flow is detected at the ejector outlet; and if the outlet refrigerant flow < G outIf the opening of the flow regulating valve is increased by the first preset step size, the working fluid flow rate will be increased; if the outlet refrigerant flow rate is ≥ G out Then, the opening degree of the flow regulating valve and the electronic expansion valve is further adjusted according to the water temperature difference, the ejector gas pressure and the jet outlet pressure.

[0016] Furthermore, adjusting the opening of the flow regulating valve and the electronic expansion valve based on the outlet water temperature difference, the ejector gas pressure, and the jet outlet pressure includes: comparing the outlet water temperature difference ΔQ1 with a preset minimum low-temperature side water temperature deviation α1; wherein, the outlet water temperature difference ΔQ1 = |T low -T m1 |,T low This is the actual outlet water temperature on the low-temperature side, which is measured at the outlet of the evaporator on the low-temperature side. (T) m1 The target outlet water temperature is the low-temperature side. If ΔQ1 < α1, the opening of the flow regulating valve and the electronic expansion valve is further adjusted according to the ejector gas pressure. If ΔQ1 ≥ α1, the opening of the electronic expansion valve is increased by a first preset step to increase the ejector fluid flow rate.

[0017] Furthermore, adjusting the opening of the flow regulating valve and the electronic expansion valve based on the ejector gas pressure includes: comparing the ejector gas pressure with a preset maximum ejector gas limit P. max The size; wherein, the ejector gas pressure is detected at the outlet of the low-temperature side heat exchanger; if the ejector gas pressure < P max Then, the opening of the flow regulating valve is increased by the first preset step size, and the water flow rate of the low-temperature side water system is increased by the second preset step size until the ejector gas pressure reaches P. max If the ejector gas pressure is ≥ P max Then, there is no need to adjust the opening of the flow regulating valve and the electronic expansion valve; it will operate according to the current ejector fluid refrigerant flow rate.

[0018] Further, after further adjusting the opening degrees of the flow regulating valve and the electronic expansion valve according to the ejecting gas pressure, the method further comprises: comparing the ejecting outlet pressure with preset outlet pressure lower limit P1 and preset outlet pressure upper limit P2, wherein the ejecting outlet pressure is detected at the ejector outlet; if P1≤ the ejecting outlet pressure ≤ P2, the current opening degree of the electronic expansion valve is maintained; if the ejecting outlet pressure < P1, the opening degree of the electronic expansion valve is increased by a third preset step and the high-temperature side water system water flow is increased by a second preset step until the ejecting outlet pressure is equal to or greater than P1; if the ejecting outlet pressure > P2, the opening degree of the electronic expansion valve is increased by a third preset step and the high-temperature side water system water flow is increased by a second preset step until the ejecting outlet pressure is equal to or less than P2.

[0019] Further, the method further comprises: monitoring the cooling load demand of the high-temperature side and the low-temperature side of the refrigeration system; if only the low-temperature side has the cooling load demand, entering a single-stage refrigeration mode; wherein in the single-stage refrigeration mode, the first electromagnetic valve is opened and the flow regulating valve and the second electromagnetic valve are closed; if the low-temperature side and the high-temperature side both have the cooling load demand, entering a two-stage refrigeration mode; wherein in the two-stage refrigeration mode, the first electromagnetic valve is closed and the flow regulating valve and the second electromagnetic valve are opened.

[0020] The application further provides a control device of a refrigeration system, wherein the device comprises: an acquisition module configured to acquire operating parameters of the refrigeration system in a two-stage refrigeration mode; and a control module configured to adjust the opening degrees of a flow regulating valve and an electronic expansion valve according to the operating parameters; wherein the flow regulating valve is configured to regulate the flow of high-temperature refrigerant and the electronic expansion valve is configured to regulate the flow of low-temperature refrigerant.

[0021] The application further provides a refrigeration system comprising the control device of the refrigeration system.

[0022] The application further provides a computer readable storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the method described above.

[0023] The technical scheme of the application can be used to control the flow of low-temperature refrigerant and high-temperature refrigerant by the electronic expansion valve and the flow regulating valve respectively, so that the water temperature of the high-temperature stage and the low-temperature stage can be independently regulated. The operating parameters of the ejector can be controlled by adjusting the ejecting fluid refrigerant flow to adjust the ejecting pressure and by adjusting the working fluid flow to adjust the outlet pressure, so as to improve the ejecting coefficient and make the ejector play a greater role on the basis of meeting the actual load demand. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a structural schematic diagram of an evaporation temperature system in the related art;

[0025] Figure 2 is a structural schematic diagram of a refrigeration system according to an embodiment of the present application;

[0026] Figure 3 is a preferred structural schematic diagram of a refrigeration system according to an embodiment of the present application;

[0027] Figure 4 is a flow chart of a control method of a refrigeration system according to an embodiment of the present application;

[0028] Figure 5 is a preferred flow chart of a control method of a refrigeration system according to an embodiment of the present application;

[0029] Figure 6 is a structural schematic diagram of a control device of a refrigeration system according to an embodiment of the present application. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present application clearer, the following will further describe the present application in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the scope of the present application.

[0031] The terms used in the embodiments of the present application are only for the purpose of describing particular embodiments and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Plural" generally includes at least two.

[0032] It should be understood that the term "and / or" used herein only describes an association relationship of associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0033] Depending on the context, the word "if" as used herein can be interpreted as meaning "when" or "upon" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if it is determined" or "if (a stated condition or event) is detected" can be interpreted as meaning "when it is determined" or "in response to determining" or "when (a stated condition or event) is detected" or "in response to detecting (a stated condition or event)".

[0034] It should also be noted that the terms "comprising", "containing" or any other similar term are intended to encompass non-exclusive inclusions, such that a product or an apparatus that comprises a list of elements does not only include those elements, but can also include other elements not expressly listed, or other elements inherent to such product or apparatus. Without more limitations, an element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the product or apparatus that includes the element.

[0035] The optional embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0036] Embodiment 1

[0037] The existing evaporation temperature system only relies on the structure limitation of an electronic expansion valve and an ejector itself to adjust the refrigerant flow of the low-temperature stage and the high-temperature stage, so that the refrigerant flow of the low-temperature stage and the high-temperature stage cannot be independently adjusted, and the water temperature cannot be accurately controlled. There is also a problem that the actual operating parameters of the ejector deviate from the design parameters, and the entrainment coefficient is low.

[0038] The design parameters of the ejector usually include working gas pressure, entrainment pressure, outlet pressure, and outlet mass flow. Research shows that, when other parameters remain unchanged, the entrainment coefficient of the ejector first increases and then decreases with the increase of the outlet pressure; when the entrainment pressure is lower than a certain value, the entrainment coefficient increases with the increase of the entrainment pressure, and when the entrainment pressure continues to increase, the entrainment coefficient will no longer be affected. Therefore, on the basis of ensuring that the actual load demand is met, adjusting the operating parameters of the ejector can improve the entrainment coefficient of the ejector and ensure the efficiency of the ejector.

[0039] Figure 2 is a structural schematic diagram of a refrigeration system according to an embodiment of the present application, as shown in Figure 2 The refrigeration system mainly includes a compressor 1, a flow regulating valve 2, a high-temperature side condenser 3, a low-temperature side condenser 4, a high-temperature side evaporator 6, a low-temperature side evaporator 7, an ejector 8, a solenoid valve 9, and an electronic expansion valve 10. Compared with the evaporation temperature system of the related art, the flow regulating valve 2 is additionally provided, so that the high-temperature stage refrigerant and the low-temperature stage refrigerant can be independently adjusted.

[0040] Figure 3 is a preferred structural schematic diagram of a refrigeration system according to an embodiment of the present application, as shown in Figure 3As shown, the above refrigeration system is additionally provided with a first electromagnetic valve 9 arranged on the pipeline between the compressor 1 and the high-temperature side condenser 3. The first electromagnetic valve 9 and the flow regulating valve 2 can together realize independent adjustment of the high-temperature level refrigerant and the low-temperature level refrigerant. The above refrigeration system further comprises a regenerator 5 arranged on the pipeline between the compressor 1 and the high-temperature side evaporator 6, and also arranged on the pipeline between the low-temperature side condenser 4 and an electronic expansion valve 10; the electronic expansion valve 10 is arranged on the pipeline between the regenerator 5 and the low-temperature side evaporator 7.

[0041] The refrigerant flow direction of the above refrigeration system is as follows: the high-temperature side fluid flows to the first electromagnetic valve 9 from the compressor 1, and then flows to the high-temperature side condenser 3; the working fluid flowing through the flow regulating valve 2 flows to the ejector 8; the low-temperature side fluid flows to the low-temperature side condenser 4 from the compressor 1, flows through the high-pressure side of the regenerator 5, passes through the electronic expansion valve 10, and then enters the low-temperature side evaporator 7 after throttling; the injection fluid from the low-temperature side evaporator 7 mixes with the working fluid of the high-temperature side, enters the high-temperature side evaporator 6 after passing through the mixing area of the ejector, absorbs heat after evaporating, enters the low-pressure side of the regenerator 5, and then enters the compressor 1 after further absorbing heat.

[0042] Based on the above introduction of the refrigerant flow direction, it can be known that the flow regulating valve 2 can realize adjustment of the high-temperature side refrigerant flow in the dual-stage refrigeration mode; or, the flow regulating valve 2 and the first electromagnetic valve 9 cooperate to realize adjustment of the high-temperature side refrigerant flow in the dual-stage refrigeration mode. The electronic expansion valve 10 can realize adjustment of the low-temperature side refrigerant flow in the dual-stage refrigeration mode. Based on this, the refrigeration system of the embodiment can realize independent adjustment of the high-temperature level and the low-temperature level water temperature.

[0043] The application scenario of the above dual-stage refrigeration mode is the case that there is a cold load demand on both the low-temperature side and the high-temperature side. The refrigeration system of the embodiment can realize the single-stage refrigeration mode in addition to the dual-stage refrigeration mode, and can execute the single-stage refrigeration mode when there is only a cold load demand on the low-temperature side.

[0044] As Figure 3As shown, the system further comprises: a second electromagnetic valve 11 arranged on the single-stage pipeline, one end of the single-stage pipeline being located between the low-temperature side evaporator 7 and the ejector 8, and the other end being connected to the refrigerant outlet of the high-temperature side evaporator 6, preferably between the high-temperature side evaporator 6 and the regenerator 5. The second electromagnetic valve 11 is used to open when there is only a cold load demand on the low-temperature side, so as to realize the single-stage refrigeration mode; wherein, in the single-stage refrigeration mode, the flow regulating valve 2 and the first electromagnetic valve 9 are closed. The second electromagnetic valve 11 cooperates with the electronic expansion valve 10 to realize the adjustment of the refrigerant flow on the low-temperature side in the single-stage refrigeration mode. The second electromagnetic valve 11 is also used to close when there is a cold load demand on both the low-temperature side and the high-temperature side, so as to realize the two-stage refrigeration mode; wherein, in the two-stage refrigeration mode, the flow regulating valve 2 and the first electromagnetic valve 9 are opened. It should be noted that the arrow direction represents the direction of the chilled water inlet and outlet, and the direction of the chilled water inlet and outlet is opposite to the direction of the refrigerant.

[0045] Based on this, the refrigeration system of the embodiment can not only realize the independent adjustment of the water temperatures of the high-temperature stage and the low-temperature stage, but also realize the selection of the single-stage refrigeration mode and the two-stage refrigeration mode according to the cold load demand on the low-temperature side and the high-temperature side.

[0046] Embodiment 2

[0047] Figure 4 The flow chart of the control method of the refrigeration system according to the embodiment of the application is shown in FIG. 4, which comprises the following steps: Figure 4 As shown in FIG. 4, the flow chart comprises the following steps:

[0048] In step S401, the operating parameters of the refrigeration system are obtained in the two-stage refrigeration mode.

[0049] In step S402, the opening degrees of the flow regulating valve and the electronic expansion valve are adjusted according to the operating parameters; wherein, the flow regulating valve is used to realize the adjustment of the refrigerant flow on the high-temperature stage, and the electronic expansion valve is used to realize the adjustment of the refrigerant flow on the low-temperature stage.

[0050] In this embodiment, the electronic expansion valve and the flow regulating valve are respectively used to control the refrigerant flow on the low-temperature stage and the high-temperature stage, so that the water temperatures of the high-temperature stage and the low-temperature stage can be independently adjusted. The operating parameters of the ejector are controlled by adjusting the induced fluid refrigerant flow to adjust the induced pressure and by adjusting the working fluid flow to adjust the outlet pressure, so as to improve the injection coefficient and make the ejector play a greater role on the basis of meeting the actual load demand.

[0051] It should be noted that the operating parameters at least include: the outlet refrigerant flow, the water temperature difference, the induced gas pressure and the ejector outlet pressure. The outlet refrigerant flow is detected at the outlet of the ejector; the water temperature difference ΔQ1 = |T low -T m1 |, T lowTlow is the actual outlet water temperature of the low-temperature side, i.e., detected at the outlet of the low-temperature side evaporator, T m1 Tlow is the target outlet water temperature of the low-temperature side; the above-mentioned injection gas pressure is detected at the outlet of the low-temperature side heat exchanger; and the above-mentioned injection outlet pressure is detected at the outlet of the injector.

[0052] In this embodiment, when adjusting the opening degrees of the flow regulating valve and the electronic expansion valve according to the operating parameters, the adjustment is performed in the following stages:

[0053] 1) The opening degrees of the flow regulating valve and the electronic expansion valve are adjusted according to the outlet refrigerant flow, specifically: the size of the outlet refrigerant flow is compared with the preset refrigerant flow G out .

[0054] 2) If the outlet refrigerant flow < G out , the opening degree of the flow regulating valve is increased by a first preset step size to increase the working fluid flow. It should be noted that the outlet refrigerant flow < G out indicates that the sum of the liquid refrigerant flows of the injection fluid and the working fluid is less than the liquid refrigerant flow under the design condition at this time, and the injection capacity of the injector is insufficient at this time, so the working fluid flow needs to be increased, which can increase the working fluid flow by a step size β (the first preset step size).

[0055] 3) If the outlet refrigerant flow ≥ G out , the opening degrees of the flow regulating valve and the electronic expansion valve are further adjusted according to the outlet water temperature difference, the injection gas pressure and the injection outlet pressure.

[0056] The above step 3) of further adjusting the opening degrees of the flow regulating valve and the electronic expansion valve according to the outlet water temperature difference, the injection gas pressure and the injection outlet pressure comprises:

[0057] 311) The size of the outlet water temperature difference ΔQ1 is compared with the preset minimum low-temperature side water temperature deviation α1.

[0058] 312) If ΔQ1 ≥ α1, the opening degree of the electronic expansion valve is increased by a first preset step size to increase the injection fluid flow.

[0059] 313) If ΔQ1 < α1, the opening degrees of the flow regulating valve and the electronic expansion valve are further adjusted according to the injection gas pressure.

[0060] The above step 313) comprises:

[0061] a) The size of the injection gas pressure is compared with the preset maximum injection gas limit P max .

[0062] b) If the injection gas pressure < P max, the ejector gas pressure needs to be increased, the opening of the flow regulating valve is increased by a first preset step size, the water flow of the low-temperature side water system is increased by a second preset step size (step size ε) to meet the outlet water temperature requirement, until the ejector gas pressure reaches P max .

[0063] c) If the ejector gas pressure ≥ P max , the opening of the flow regulating valve and the electronic expansion valve does not need to be adjusted, and the current ejector fluid refrigerant flow is run, at this time the injection coefficient of the ejector is the highest.

[0064] After step 313), comprising:

[0065] 314) Compare the injection outlet pressure with the preset outlet pressure lower limit P1 and the preset outlet pressure upper limit P2.

[0066] If P1≤ injection outlet pressure ≤ P2, the current opening of the electronic expansion valve is maintained.

[0067] If the injection outlet pressure < P1, the opening of the electronic expansion valve is increased by a third preset step size (step size γ), and the water flow of the high-temperature side water system is increased by a second preset step size (step size ε), until the injection outlet pressure is equal to or greater than P1.

[0068] If the injection outlet pressure > P2, the opening of the electronic expansion valve is increased by a third preset step size (step size γ), and the water flow of the high-temperature side water system is increased by a second preset step size (step size ε), until the injection outlet pressure is equal to or less than P2.

[0069] Based on this, the adjustment of the opening of the flow regulating valve and the electronic expansion valve according to the outlet refrigerant flow, the outlet water temperature difference, the ejector gas pressure and the injection outlet pressure is completed. Thus, independent adjustment of the refrigerant flow of the high-temperature stage and the low-temperature stage is realized, and then independent adjustment of the water temperature of the high-temperature stage and the low-temperature stage is realized, and the water temperature can be accurately controlled.

[0070] In addition to the dual-stage refrigeration mode, the embodiment can also realize a single-stage refrigeration mode. The dual-stage refrigeration mode is executed when there is a cold load demand on both the low-temperature side and the high-temperature side, and the single-stage refrigeration mode is executed when there is only a cold load demand on the low-temperature side. Based on this, the embodiment provides a preferred implementation, that is, monitoring the cold load demand of the high-temperature side and the low-temperature side of the refrigeration system; if there is only a cold load demand on the low-temperature side, entering the single-stage refrigeration mode; wherein, in the single-stage refrigeration mode, the first electromagnetic valve is opened, and the flow regulating valve and the second electromagnetic valve are closed; if there is a cold load demand on both the low-temperature side and the high-temperature side, entering the dual-stage refrigeration mode; wherein, in the dual-stage refrigeration mode, the first electromagnetic valve is closed, and the flow regulating valve and the second electromagnetic valve are opened.

[0071] Based on this, the refrigeration system of the embodiment can not only realize independent adjustment of water temperature of high-temperature stage and low-temperature stage, but also realize selection of single-stage refrigeration mode and double-stage refrigeration mode according to cold load demand of the low-temperature side and the high-temperature side.

[0072] Embodiment 3

[0073] Figure 5 The control method of the refrigeration system according to the embodiment of the application is preferably a flow chart as shown in Figure 5 , which comprises the following steps:

[0074] In step S501, operating parameters of the refrigeration system are acquired. The operating parameters at least include outlet refrigerant flow G8, outlet water temperature difference ΔQ1, ejecting gas pressure P7 and injection outlet pressure P6.

[0075] In step S502, G8 is compared with preset refrigerant flow (i.e. liquid refrigerant flow under design condition) G out . If G8 out , it indicates that the sum of the liquid refrigerant flow of the ejecting fluid and the working fluid is less than the liquid refrigerant flow under the design condition, at this time, the ejecting capacity of the ejector is insufficient, and the flow of the ejecting fluid needs to be increased, and the flow of the working fluid is increased by step β; if G8≥G out , step S503 is executed.

[0076] In step S503, whether the outlet water temperature of the low-temperature side meets the actual outlet water demand is judged, i.e. whether outlet water temperature difference ΔQ1 low m1 is less than preset low-temperature side water temperature deviation minimum value α1 is established, if yes, step S504 is executed, if no, the flow of the ejecting fluid is increased by step β.

[0077] Wherein, outlet water temperature difference ΔQ1 low m1 = |T low m1 is the actual outlet water temperature of the low-temperature side, which is detected at the outlet of the low-temperature side evaporator, and T m1 is the target outlet water temperature of the low-temperature side.

[0078] In step S504, whether the ejecting gas pressure P7 is less than preset ejecting gas maximum limit value P max is judged. If P7 max , the ejecting pressure needs to be increased, at this time, the opening degree of the flow regulating valve needs to be increased by step β, at this time, in order to meet the outlet water temperature, the water flow of the low-temperature side water system is increased by step ε until the preset ejecting gas maximum limit value P max is reached; if P7≥P max , the refrigeration system is operated with the flow of the ejecting fluid at this time, at this time, the injection coefficient of the ejector is the highest. Then, step S505 is executed.

[0079] Step S505, judging the size relation between the injection outlet pressure P6 and the outlet pressure limit value (the preset outlet pressure minimum limit value P1, the preset outlet pressure maximum limit value P2), that is, judging whether P1≤P6≤P2 is established, if yes, maintaining the electronic expansion valve opening degree at this time, if no, judging whether P6

[0080] If P6

[0081] It should be noted that the injection coefficient of the ejector increases first and then decreases with the increase of the outlet pressure under the condition that other parameters remain unchanged; when the injection gas pressure is lower than a certain value, the injection coefficient increases with the increase of the injection gas pressure, and the injection coefficient will no longer be affected when the injection gas pressure continues to increase, therefore, the values of P1 and P2 are mainly based on the outlet pressure setting value P out , the preset injection gas maximum limit value P max is mainly determined by the structure of the ejector.

[0082] The embodiment controls the electronic expansion valve and the flow regulating valve through a series of operating parameters, so as to control the refrigerant flow of the high-temperature stage and the low-temperature stage respectively, so that the water temperature of the high-temperature stage and the low-temperature stage can be independently adjusted. The injection pressure is adjusted by adjusting the injection fluid refrigerant flow of the ejector, and the outlet pressure is adjusted by adjusting the working fluid flow, so as to control the operating parameters of the ejector, so as to improve the injection coefficient, and to play a greater role of the ejector on the basis of meeting the actual load demand.

[0083] Embodiment 4

[0084] Corresponding to the control method flow chart of the refrigeration system shown in Figure 4 , the embodiment provides a control device of a refrigeration system, Figure 6 is a structural schematic diagram of the control device of the refrigeration system according to the embodiment of the application, as shown in Figure 6 , the device comprises:

[0085] The acquisition module 10 is used for acquiring operating parameters of the refrigeration system in the double-stage refrigeration mode.

[0086] The control module 20 is connected to the acquisition module 10, and is used for adjusting the opening degrees of the flow regulating valve and the electronic expansion valve according to the operating parameters; wherein the flow regulating valve is used for realizing the adjustment of the high-temperature stage refrigerant flow, and the electronic expansion valve is used for realizing the adjustment of the low-temperature stage refrigerant flow.

[0087] The control device of the refrigeration system of the embodiment can realize independent adjustment of the refrigerant flow of the low-temperature stage and the high-temperature stage, and the specific implementation scheme has been described in detail before, which will not be described here. The embodiment adjusts the injection fluid refrigerant flow of the ejector to adjust the injection pressure, adjusts the working fluid flow to adjust the outlet pressure, so as to control the operating parameters of the ejector, so as to improve the injection coefficient, and to play a greater role of the ejector on the basis of meeting the actual load demand.

[0088] The embodiment also provides a refrigeration system comprising the control device of the refrigeration system.

[0089] Embodiment 5

[0090] The embodiment of the application provides a software for executing the technical solutions described in the above embodiments and preferred embodiments.

[0091] The embodiment of the application provides a nonvolatile computer storage medium, which stores computer executable instructions, and the computer executable instructions can execute the control method of the refrigeration system in any method embodiment.

[0092] The storage medium stores the software, and the storage medium includes but is not limited to an optical disc, a floppy disk, a hard disk, a rewritable memory, and the like.

[0093] The product can execute the method provided in the embodiment of the application, has a function module corresponding to the executed method and beneficial effects. Technical details not described in detail in the embodiment can be referred to the method provided in the embodiment of the application.

[0094] The device embodiments described above are only schematic, wherein the units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, that is, can be located in one place, or can be distributed on multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0095] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be realized by means of software and necessary general hardware platform, and of course can also be realized by hardware. Based on such understanding, the above technical solutions can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the method described in each embodiment or some parts of the embodiment.

[0096] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features therein can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A refrigeration system characterized by, The system comprises a compressor (1), a high-temperature side condenser (3), a low-temperature side condenser (4), a high-temperature side evaporator (6), a low-temperature side evaporator (7), an ejector (8), and an electronic expansion valve (10) arranged on a pipeline between the low-temperature side condenser (4) and the low-temperature side evaporator (7), and further comprises: a flow regulating valve (2) arranged on a pipeline between the high-temperature side condenser (3) and the ejector (8).

2. The system of claim 1, wherein, The system further comprises: a first electromagnetic valve (9) arranged on a pipeline between the compressor (1) and the high-temperature side condenser (3).

3. The system according to claim 2, wherein the flow regulating valve (2) is configured to regulate the flow of the high-temperature side refrigerant in the dual-stage refrigeration mode; or the flow regulating valve (2) and the first electromagnetic valve (9) are configured to cooperate to regulate the flow of the high-temperature side refrigerant in the dual-stage refrigeration mode. the electronic expansion valve (10) is configured to regulate the flow of the low-temperature side refrigerant in the dual-stage refrigeration mode.

4. The system of claim 2, wherein, The system further comprises: a second electromagnetic valve (11) arranged on a single-stage pipeline, one end of the single-stage pipeline being arranged between the low-temperature side evaporator (7) and the ejector (8), and the other end being connected to a refrigerant outlet of the high-temperature side evaporator (6).

5. The system according to claim 4, wherein the second electromagnetic valve (11) is configured to be opened to realize the single-stage refrigeration mode when there is only a cooling load demand on the low-temperature side, and the flow regulating valve (2) and the first electromagnetic valve (9) are closed in the single-stage refrigeration mode; the second electromagnetic valve (11) is further configured to be closed to realize the dual-stage refrigeration mode when there are cooling load demands on both the low-temperature side and the high-temperature side, and the flow regulating valve (2) and the first electromagnetic valve (9) are opened in the dual-stage refrigeration mode.

6. The system according to claim 4, wherein the second electromagnetic valve (11) is configured to cooperate with the electronic expansion valve (10) to regulate the flow of the low-temperature side refrigerant in the single-stage refrigeration mode.

7. The system of claim 1, wherein, The system further comprises: a regenerator (5) arranged on a pipeline between the compressor (1) and the high-temperature side evaporator (6), and also arranged on a pipeline between the low-temperature side condenser (4) and the electronic expansion valve (10); the electronic expansion valve (10) is arranged on a pipeline between the regenerator (5) and the low-temperature side evaporator (7).

8. A control method of a refrigeration system applied to the refrigeration system according to any one of claims 1 to 7, characterized by, The method comprises: in the dual-stage refrigeration mode, obtaining operating parameters of the refrigeration system; adjusting the opening degrees of the flow regulating valve and the electronic expansion valve according to the operating parameters, wherein the flow regulating valve is configured to regulate the flow of the high-temperature side refrigerant, and the electronic expansion valve is configured to regulate the flow of the low-temperature side refrigerant.

9. The method of claim 8, wherein, The operating parameters at least include: outlet refrigerant flow, outlet water temperature difference, ejector gas pressure, and ejector outlet pressure.

10. The method of claim 9, wherein, Adjusting the opening degrees of the flow regulating valve and the electronic expansion valve according to the operating parameters comprises: comparing the outlet refrigerant flow rate with a predetermined refrigerant flow rate G out ; wherein the outlet refrigerant flow rate is detected at the ejector outlet If the outlet refrigerant flow < G out then increase the opening of the flow regulating valve by a first predetermined step to increase the working fluid flow If the outlet refrigerant flow > G out then adjust the opening of the flow regulating valve and electronic expansion valve based on the outlet water temperature difference, the ejector gas pressure, and the injection outlet pressure.

11. The method of claim 10, wherein, Adjusting the opening degree of the flow regulating valve and the electronic expansion valve according to the water outlet temperature difference, the ejector gas pressure and the injection outlet pressure, comprising: comparing the outlet water temperature difference AQ1 with a preset low-temperature-side water temperature deviation minimum value a1, wherein the outlet water temperature difference AQ1 = |T low -T m1 |, T low is a low-temperature-side actual outlet water temperature, which is detected at the outlet of the low-temperature-side evaporator, and T m1 is a low-temperature-side target outlet water temperature; If ΔQ1<α1, adjusting the opening degree of the flow regulating valve and the electronic expansion valve according to the ejector gas pressure; If ΔQ1≥α1, increasing the opening degree of the electronic expansion valve by a first preset step to increase the flow of the ejector fluid.

12. The method of claim 11, wherein, Adjusting the opening degree of the flow regulating valve and the electronic expansion valve according to the ejector gas pressure, comprising: comparing the ejecting gas pressure with a preset ejecting gas maximum limit value P max ; wherein the ejecting gas pressure is detected at the outlet of the low-temperature side heat exchanger; If the ejecting gas pressure < P max , then increase the opening of the flow regulating valve by a first preset step and increase the low-temperature side water system water flow by a second preset step until the ejecting gas pressure reaches the P max ; If the injection gas pressure ≥ P max then no adjustment of the opening of the flow regulating valve and electronic expansion valve is required and operation proceeds with the current injection fluid refrigerant flow.

13. The method according to claim 11 or 12, characterized in that, After adjusting the opening degree of the flow regulating valve and the electronic expansion valve according to the ejector gas pressure, the method further comprises: Comparing the injection outlet pressure with preset minimum outlet pressure P1 and preset maximum outlet pressure P2; wherein the injection outlet pressure is detected at the outlet of the injector; If P1≤the injection outlet pressure≤P2, keeping the current opening degree of the electronic expansion valve; If the injection outlet pressure If the injection outlet pressure 14. The method according to any one of claims 8 to 13, characterized in that, The method further comprises: Monitoring the cooling load demand of the high-temperature side and the low-temperature side of the refrigeration system; If only the low-temperature side has a cooling load demand, entering a single-stage refrigeration mode; wherein in the single-stage refrigeration mode, the first electromagnetic valve is opened, and the flow regulating valve and the second electromagnetic valve are closed; If the low-temperature side and the high-temperature side both have a cooling load demand, entering a two-stage refrigeration mode; wherein in the two-stage refrigeration mode, the first electromagnetic valve is closed, and the flow regulating valve and the second electromagnetic valve are opened.

15. A control device for the refrigeration system as claimed in any one of claims 1 to 7, characterized in that The device comprises: An acquisition module, configured to acquire operating parameters of the refrigeration system in the two-stage refrigeration mode; A control module, configured to adjust the opening degree of the flow regulating valve and the electronic expansion valve according to the operating parameters; wherein the flow regulating valve is used to regulate the flow of the high-temperature refrigerant, and the electronic expansion valve is used to regulate the flow of the low-temperature refrigerant.

16. A refrigeration system characterized by, The refrigeration system at least comprises the control device of the refrigeration system according to claim 15.

17. A computer readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the method according to any one of claims 8 to 14. The program is executed by the processor to implement the method according to any one of claims 8 to 14.

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