Refrigeration system

Abstract

The utility model discloses a refrigerating system. The refrigerating system comprises an evaporator, a condenser, a compressor, a pressure switch, a valve and a throttling pipeline which are connected through a refrigerant pipeline. Wherein an outlet of the evaporator communicates with an air return port of the compressor through a first refrigerant pipeline, an outlet of the compressor communicates with an inlet of the condenser through a second refrigerant pipeline, and an outlet of the condenser communicates with an inlet of the evaporator through a third refrigerant pipeline; the pressure switch is arranged on the first refrigerant pipeline close to the air return port side and used for obtaining the pressure value of the air return port, determining that the pressure value meets a set threshold value and generating and sending a control signal; the valve is arranged on the first refrigerant pipeline far away from the air return port side; the throttling pipeline is connected to the two ends of the valve in a bridging mode and communicates with the first refrigerant pipeline, and the diameter of the throttling pipeline is smaller than that of the first refrigerant pipeline. And the valve is used for outputting the refrigerant at the outlet of the evaporator to the air return port of the compressor based on the throttling pipeline and / or the first refrigerant pipeline based on the control signal.

Description

Technical Field

[0001] The present application relates to the field of refrigeration technology, and in particular to a refrigeration system. Background Art

[0002] With the development of industries such as freezing and refrigeration, and cold chain transportation, people have higher requirements for the reliability of refrigeration systems. However, in refrigeration systems with a wide cooling range, when the internal and external working conditions change greatly, the mass flow rate of the refrigerant will change dramatically. This change often causes a substantial increase in the power of the compressor, and even causes the compressor to burn out due to overcurrent, or the compressor drive motor or drive prime mover to stall.

[0003] In the related art, in order to avoid this problem, a back pressure control valve or a flow control valve is usually added to the system, but the flow control structure often brings new problems, such as increased costs and large suction losses of the refrigeration system during normal use. Utility Model Content

[0004] In view of this, an embodiment of the present application provides a refrigeration system that can improve the reliability of the refrigeration system while reducing costs.

[0005] The technical solution of the embodiment of the present application is implemented as follows:

[0006] The embodiment of the present application provides a refrigeration system, the refrigeration system comprising: an evaporator, a condenser and a compressor connected via a refrigerant pipeline, wherein the outlet of the evaporator is connected to the return air port of the compressor via a first refrigerant pipeline, the outlet of the compressor is connected to the inlet of the condenser via a second refrigerant pipeline, and the outlet of the condenser is connected to the inlet of the evaporator via a third refrigerant pipeline; the refrigeration system further comprises:

[0007] A pressure switch, the pressure switch is arranged on the first refrigerant pipeline near the return air port side, and is used to obtain the pressure value of the return air port, and determine whether the pressure value meets a set threshold, and generate and send a control signal;

[0008] A valve, wherein the valve is arranged on the first refrigerant pipeline away from the return air port side;

[0009] a throttling pipeline, the throttling pipeline being connected across two ends of the valve and being in communication with the first refrigerant pipeline, the throttling pipeline having a smaller diameter than the first refrigerant pipeline;

[0010] The valve is used to switch the working state based on the control signal so that the refrigerant at the outlet of the evaporator is output to the return air port of the compressor based on the throttling pipeline and / or the first refrigerant pipeline.

[0011] In some embodiments, a first node close to the air return port and a second node far from the air return port are provided on the first refrigerant pipeline, the first refrigerant pipeline includes a compressor air return pipeline, a valve control pipeline and an evaporator output pipeline, and the compressor air return pipeline, the valve control pipeline and the evaporator output pipeline are connected in sequence;

[0012] The return air port and the first node are connected via the compressor return air pipeline; the first node and the second node are connected via the valve control pipeline, and the second node and the outlet of the evaporator are connected via the evaporator output pipeline;

[0013] The pressure switch is arranged on the compressor return air pipeline, the valve is arranged on the valve control pipeline, and the throttling pipeline is connected across the two ends of the valve and communicated with the valve control pipeline;

[0014] The diameter of the evaporator output pipeline is larger than the diameter of the valve control pipeline and the diameter of the compressor return pipeline.

[0015] In some embodiments, the refrigeration system further comprises:

[0016] A gas-liquid separator, the gas-liquid separator is arranged on the compressor return air pipeline, and is used to recover the liquid refrigerant in the compressor return air pipeline;

[0017] The gas-liquid separator comprises an air inlet end and a air outlet end;

[0018] The compressor return air pipeline includes a first return air pipeline and a second return air pipeline;

[0019] The air return port is connected to the air outlet via the first air return pipeline, and the air inlet is connected to the first node via the second air return pipeline.

[0020] In some embodiments, the refrigeration system further comprises:

[0021] A signal line, the pressure switch and the valve are connected via the signal line, and the signal line is used to transmit the control signal to the valve.

[0022] In some embodiments, the refrigeration system further comprises:

[0023] A liquid storage tank, the liquid storage tank is arranged on the third refrigerant pipeline near the outlet side of the condenser, and the liquid storage tank includes a liquid inlet and a liquid outlet;

[0024] The third refrigerant pipeline includes a condenser output pipeline and an evaporator input pipeline;

[0025] The outlet of the condenser and the liquid inlet are connected via the condenser output pipeline, and the liquid outlet and the inlet of the evaporator are connected via the evaporator input pipeline.

[0026] In some embodiments, the refrigeration system further comprises:

[0027] A drying filter is arranged on the evaporator input pipeline close to the liquid outlet side.

[0028] In some embodiments, the refrigeration system further comprises:

[0029] A throttling device is arranged on the evaporator input pipeline close to the inlet side of the evaporator.

[0030] In some embodiments, the refrigeration system further comprises:

[0031] a fourth refrigerant pipeline, the fourth refrigerant pipeline being connected to an inlet of the evaporator and an outlet of the compressor;

[0032] A defrost valve is provided on the fourth refrigerant pipeline and is used to control the fourth refrigerant pipeline to be turned on or off.

[0033] In some embodiments, the valve is an electrically controlled valve, a gas controlled valve, or a hydraulically controlled valve, and the valve is used to close or reduce the opening based on the control signal.

[0034] In some embodiments, the refrigeration system further comprises:

[0035] a first fan, wherein the first fan is disposed on the evaporator;

[0036] A second fan is arranged on the condenser.

[0037] The embodiment of the present application provides a refrigeration system, which includes: an evaporator, a condenser, a compressor, a pressure switch, a valve and a throttling pipeline connected via a refrigerant pipeline; wherein the outlet of the evaporator is connected to the return air port of the compressor via a first refrigerant pipeline, the outlet of the compressor is connected to the condenser via a second refrigerant pipeline, and the outlet of the condenser is connected to the inlet of the evaporator via a third refrigerant pipeline; the refrigeration system also includes: a pressure switch is arranged on the first refrigerant pipeline close to the return air port side, for obtaining the pressure value of the return air port, and determining that the pressure value meets the set threshold, generating and sending a control signal; the valve is arranged on the first refrigerant pipeline away from the return air port side; the throttling pipeline is bridged across both ends of the valve and is connected to the first refrigerant pipeline, and the diameter of the throttling pipeline is smaller than that of the first refrigerant pipeline; the valve is used to obtain and switch the working state of the valve based on the control signal, so that the refrigerant at the outlet of the evaporator is output to the return air port of the compressor based on the throttling pipeline and / or the first refrigerant pipeline.

[0038] Thus, the embodiment of the present application introduces a dual-pipeline design (a first refrigerant pipeline and a throttling pipeline) and a control structure of a pressure switch and a valve, and the diameter of the throttling pipeline is smaller than the diameter of the first refrigerant pipeline. When the pressure value meets the set threshold, the valve can control the refrigerant at the evaporator outlet to return to the return air port of the compressor through the throttling pipeline and / or the first refrigerant pipeline, thereby accurately regulating the refrigerant flow at the evaporator outlet under different pressure conditions, effectively alleviating pressure fluctuations, reducing the impact on the compressor, improving the reliability of the refrigeration system, reducing costs, and improving user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the connection structure of a refrigeration system in the related art;

[0040] Figure 2 This is a schematic diagram of the structure of the refrigeration system according to an embodiment of the present application.

[0041] Description of reference numerals:

[0042] 1. Evaporator; 1a. Evaporator outlet; 1b. Evaporator inlet;

[0043] 2. Compressor; 2a. Air return port; 2b. Air outlet;

[0044] 3. Condenser; 3a. Inlet of condenser; 3b. Outlet of condenser;

[0045] 4. First refrigerant pipeline; A. First node; B. Second node; 41. Compressor return air pipeline; 411. First return air pipeline; 412. Second return air pipeline; 42. Valve control pipeline; 43. Evaporator output pipeline;

[0046] 5. Second refrigerant pipeline;

[0047] 6. The third refrigerant pipeline; 61. The condenser output pipeline; 62. The evaporator input pipeline;

[0048] 7. Pressure switch; 8. Valve; 9. Throttle pipeline;

[0049] 10. Gas-liquid separator; 10a. gas inlet end; 10b. gas outlet end;

[0050] 11. Signal line;

[0051] 12. Liquid storage tank; 12a. Liquid inlet; 12b. Liquid outlet;

[0052] 13. Dry filter; 14. Throttling device;

[0053] 15. The fourth refrigerant pipeline; 16. Defrost valve;

[0054] 17. First fan; 18. Second fan. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings. The described embodiments should not be regarded as limiting the present application. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0056] In the description of the present application, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it can be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0057] In the description of the present application, the terms "first, second" and the like are only used to distinguish similar objects and do not represent a specific order of the objects. It is understandable that "first, second" and the like can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. Unless otherwise specified, "plurality" means at least two.

[0058] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0059] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0060] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0061] In the related art, the structural diagram of the refrigeration system is as follows: Figure 1 As shown, the refrigeration system includes: an evaporator 1, a condenser 3 and a compressor 2 connected via refrigerant pipelines, wherein the outlet 1a of the evaporator is connected to the return air port 2a of the compressor 2 via a first refrigerant pipeline 4, the outlet 2b of the compressor 2 is connected to the inlet 3a of the condenser via a second refrigerant pipeline 5, and the outlet 3b of the condenser is connected to the inlet 1b of the evaporator via a third refrigerant pipeline 6.

[0062] In the related art, the refrigeration cycle of the refrigeration system is as follows Figure 1 As shown by the arrows, the refrigerant (also called refrigerant) at the outlet 1a of the evaporator passes through the first refrigerant pipeline 4, and circulates through the compressor 2, the condenser 3 and the inlet 1b of the evaporator in sequence.

[0063] For example, the low-temperature and low-pressure refrigerant from the evaporator 1 is sucked in through the first refrigerant pipeline 4 through the return air port 2a of the compressor 2, compressed into high-temperature and high-pressure gas inside the compressor 2, and discharged through the air outlet 2b of the compressor 2. The high-temperature and high-pressure gas passes through the second refrigerant pipeline 5, enters the condenser 3 through the inlet 3a of the condenser to release heat, and condenses into liquid refrigerant. The liquid refrigerant passes through the third refrigerant pipeline 6 based on the outlet 3b of the condenser, enters the evaporator 1 through the inlet 1b of the evaporator to evaporate and absorb heat (at this time, the indoor air is cooled down), and enters the next cycle through the first refrigerant pipeline 4 again.

[0064] In addition, in order to avoid a huge change in the mass flow rate of the refrigerant (also called the refrigerant) at the compressor 2, the pressure at the return air port 2a of the compressor 2 is too high (i.e., the suction back pressure increases), which causes the power of the compressor 2 to increase significantly, and even causes the compressor 2 to burn out due to overcurrent or the drive motor of the compressor 2 is blocked, the drive prime mover is blocked, and other faults, such as Figure 1 As shown, the conventional solution is to add a KVL valve (suction pressure regulating valve) on the first refrigerant pipeline 4; when the suction pressure is too high, by adjusting the KVL valve, the mass flow rate of the refrigerant on the first refrigerant pipeline 4 can be controlled, thereby reducing the suction back pressure at the return air port of the compressor.

[0065] However, the solution of installing a KVL valve on the refrigerant pipeline has the following disadvantages: 1) The valve is a precision spring structure with high procurement cost; 2) The valve is connected in series on the suction pipe of the refrigeration system, i.e., the first refrigerant pipeline 4, and the minimum effective flow cross-section is much smaller than that of a normal suction pipe. During operation, a large suction throttling loss will be generated, which directly affects the refrigeration efficiency of the system. The power consumption during long-term operation will be significantly greater than that of the unit without a suction pressure regulating valve; 3) The valve structure is complex, and the sealing structure increases the risk of leakage; 4) The valve structure is relatively special and requires a larger installation space and operation adjustment space.

[0066] Based on this, the present application embodiment provides a refrigeration system, such as Figure 2 As shown, the refrigeration system includes: an evaporator 1, a condenser 2, a compressor 3, a pressure switch 7, a valve 8 and a throttling pipeline 9 connected via a refrigerant pipeline.

[0067] In an embodiment of the present application, the outlet 1a of the evaporator is connected to the return air port 2a of the compressor 2 via a first refrigerant pipeline 4, the outlet 2b of the compressor 2 is connected to the inlet 3a of the condenser via a second refrigerant pipeline 5, and the outlet 3b of the condenser is connected to the inlet 1b of the evaporator via a third refrigerant pipeline 6.

[0068] It is understandable that the refrigerant flow direction is Figure 2 In the direction of the arrow, the low-temperature and low-pressure refrigerant from the evaporator 1 passes through the first refrigerant pipeline 4, is sucked in through the return air port 2a of the compressor 2, is compressed inside the compressor 2 to become a high-temperature and high-pressure gas, and is discharged through the outlet 2b of the compressor 2. The high-temperature and high-pressure gas passes through the second refrigerant pipeline 5, enters the condenser 3 through the inlet 3a of the condenser to release heat, and condenses into liquid refrigerant. The liquid refrigerant passes through the third refrigerant pipeline 6 based on the outlet 3b of the condenser, enters the evaporator 1 through the inlet 1b of the evaporator to evaporate and absorb heat.

[0069] Here, the pressure switch 7 is disposed on the first refrigerant pipeline 4 near the return air port 2a, and is used to obtain the pressure value of the return air port 2a, determine whether the pressure value meets a set threshold, and generate and send a control signal.

[0070] For example, in order to avoid failures caused by high intake back pressure, the threshold is set to the pressure value of the return port 2a corresponding to the high intake back pressure, which can be represented by P1. P1 is the critical point of the increase of intake back pressure. Exceeding this value indicates that there is an abnormally high intake pressure on the return port 2a side.

[0071] When the pressure switch 7 determines that the pressure value of the return air port 2a is greater than or equal to the set threshold value P1, it generates and sends a control signal, which is used to control the working state of the valve 8 so that the refrigerant is output from the refrigerant at the outlet 1a of the evaporator to the return air port 2a of the compressor 2 based on the throttling line 9, or based on the throttling line 9 and the first refrigerant line 4.

[0072] Exemplarily, when the intake back pressure is normal, that is, when it is determined that the pressure value of the return air port 2a is less than the set threshold value P2, P2 is the maximum pressure value corresponding to the normal pressure value of the return air port. If the pressure value of the return air port 2a is lower than P1, it indicates that the intake back pressure is normal, where P1 is greater than P2.

[0073] When it is determined that the pressure value of the return air port 2a is less than the set threshold value P2, a control signal is generated and sent. The control signal is used to control the working state of the valve 8 so that the refrigerant from the refrigerant at the outlet 1b of the evaporator flows into the return air port 2a of the compressor 2 mainly based on the first refrigerant pipeline 4, that is, the refrigerant is controlled based on the first refrigerant pipeline 4, or based on the first refrigerant pipeline 4 and the throttling pipeline 9 to be output to the return air port 2a of the compressor 2.

[0074] Here, the valve 8 is provided on the first refrigerant pipe 4 which is away from the return air port 2a.

[0075] It is understandable that the present application does not limit the type of valve 8, and the valve 8 may be an electrically controlled valve, a gas controlled valve, or a hydraulically controlled valve, etc. The valve may be an on-off valve or a valve with an adjustable opening.

[0076] Here, the throttling pipeline 9 is connected across both ends of the valve 8 and is connected to the first refrigerant pipeline 4 . The diameter of the throttling pipeline 9 is smaller than that of the first refrigerant pipeline 4 .

[0077] It can be understood that, compared with ordinary refrigerant pipelines, the throttling pipeline 9 has a smaller diameter than the first refrigerant pipeline 4 .

[0078] Exemplarily, assuming that the diameter of the first refrigerant pipeline 4 is ΦD1, and the diameter of the throttling pipeline 9 is ΦD3, wherein the diameter ΦD3 of the throttling pipeline 9 is smaller than the diameter ΦD1 of the first refrigerant pipeline 4, the relationship between ΦD1 and ΦD3 is: ΦD3=0.5D1.

[0079] It is understandable that when the suction back pressure is high, the high-pressure refrigerant at the outlet 1b of the evaporator is controlled to flow to the return port 2a of the compressor 2 through the throttling line 9. In this process, the flow rate of the refrigerant is accelerated due to the narrowing of the flow channel. According to the Joule-Thomson effect, when the high-pressure fluid passes through the throttling line 9 with a smaller throttling diameter, it will experience a pressure drop, that is, the pressure of the high-pressure refrigerant passing through the throttling line 9 will decrease, thereby reducing the return port pressure on the compressor 2 side. In addition, the smaller the diameter of the throttling line 9, the lower the mass flow rate of the refrigerant.

[0080] In this way, when the suction back pressure is high, the refrigerant passing through the throttling line 9 experiences a pressure drop, which helps to balance the pressure of the return air port 2a of the compressor 2 and prevent the compressor 2 from being damaged by the high-pressure gas. In addition, reducing the refrigerant flow to the compressor 2 can avoid overloading the compressor 2 and maintain the stable operation and energy efficiency of the system.

[0081] Here, the valve 8 is used to switch the working state based on the control signal so that the refrigerant at the outlet 1b of the evaporator is output to the return air port 2a of the compressor 2 based on the throttling line 9 and / or the first refrigerant line 4.

[0082] It is understandable that for different valves 8, the working state of the valve 8 is different. For example, for a switch type valve, the working state of the valve 8 includes an open state and a closed state. For a switch valve with adjustable opening, its working state includes multiple working states corresponding to different openings. The opening corresponding to each working state is different.

[0083] It is understandable that by adjusting the working state of the valve 8 on the first refrigerant pipeline 4 , the refrigerant at the outlet of the evaporator 1 can be output to the return air port 2a of the compressor 2 based on the throttling pipeline 9 and / or the first refrigerant pipeline 4 .

[0084] Exemplarily, after the valve 8 is switched from the open state to the closed state, the first refrigerant pipeline 4 cannot be connected, and the refrigerant at the outlet 1b of the evaporator can only be output to the return air port 2a of the compressor 2 through the throttling pipeline 9.

[0085] Exemplarily, when the valve 8 switches from a first working state with a first set opening to a second working state with a second set opening, at this time, the first refrigerant pipeline 4 and the throttling pipeline 9 are both connected, so that the refrigerant at the outlet 1b of the evaporator 1 can be output to the return air port 2a of the compressor 2 based on the throttling pipeline 9 and the first refrigerant pipeline 4.

[0086] Exemplarily, after the valve 8 switches from the closed state to the open state, the first refrigerant pipeline 4 is fully connected. Since the diameter of the first refrigerant pipeline 4 is larger, the refrigerant at the outlet 1b of the evaporator can be mainly output to the return air port 2a of the compressor 2 based on the first refrigerant pipeline 4.

[0087] Thus, the embodiment of the present application introduces a dual-pipeline design (first refrigerant pipeline 4 and throttling pipeline 9) and a control structure of a pressure switch 7 and a valve 9, and the diameter of the throttling pipeline 9 is smaller than the diameter of the first refrigerant pipeline 4. When the pressure value meets the set threshold, the valve 9 can control the refrigerant at the outlet 1b of the evaporator to return to the return air port 2a of the compressor 2 through the throttling pipeline 9 and / or the first refrigerant pipeline 4, thereby accurately regulating the refrigerant flow at the outlet 1b of the evaporator under different pressure conditions, effectively alleviating pressure fluctuations, reducing the impact on the compressor 2, improving the reliability of the refrigeration system, reducing costs, and improving user experience.

[0088] In some embodiments, a first node A close to the air return port 2 a and a second node B far from the air return port 2 a are arranged on the first refrigerant pipeline 4 .

[0089] It can be understood that the first node A and the second node B divide the first refrigerant pipeline 4 into a compressor return air pipeline 41, a valve control pipeline 42 and an evaporator output pipeline 43, and the compressor return air pipeline 41, the valve control pipeline 42 and the evaporator output pipeline 43 are connected in sequence.

[0090] Here, the return air port 2a is connected to the first node A via the compressor return air pipeline 41; the first node A is connected to the second node B via the valve control pipeline 42, and the second node B is connected to the outlet 1b of the evaporator via the evaporator output pipeline 43.

[0091] Here, the pressure switch 7 is arranged on the compressor return air pipeline 41 , the valve 8 is arranged on the valve control pipeline 42 , and the throttling pipeline 9 is connected across both ends of the valve 8 and is in communication with the valve control pipeline 42 .

[0092] Here, the diameter of the evaporator outlet pipeline 43 is larger than the diameter of the valve control pipeline 42 and the diameter of the compressor return pipeline 41 .

[0093] Exemplarily, assuming that the diameter of the evaporator output pipeline 43 is ΦD2, the diameter of the valve control pipeline 42 and the diameter of the compressor return air pipeline 41 are the same as ΦD1, wherein the diameter ΦD2 of the evaporator output pipeline 43 is larger than the diameter of the valve control pipeline 42 and the diameter of the compressor return air pipeline 41, and the relationship between ΦD1 and ΦD2 is: ΦD1=0.9D2.

[0094] In this way, when the evaporator output pipeline 43 (diameter ΦD2) is larger than the compressor return air pipeline 41 and the valve control pipeline 43 (both with a diameter of ΦD1), this helps to reduce the flow rate of the refrigerant in the evaporator output stage and the mass flow rate of the refrigerant, thereby reducing the pressure of the refrigerant, allowing the refrigerant to have more time to fully evaporate in the evaporator 1, improving the evaporation efficiency and thus enhancing the refrigeration effect.

[0095] In some embodiments, please refer to Figure 2 The refrigeration system further includes: a gas-liquid separator 10 , which is arranged on the compressor return air pipeline 41 and is used to recover the liquid refrigerant in the compressor return air pipeline 41 .

[0096] It is understandable that if the liquid refrigerant directly enters the compressor 2, it may cause a "liquid hammer" phenomenon, that is, the liquid refrigerant is incompressible inside the compressor 2, causing damage to the compressor 2. The gas-liquid separator 10 is used to recover the liquid refrigerant in the compressor return air pipeline 41 from the gas mixture inhaled by the compressor 2, thereby allowing only gaseous refrigerant to enter the compressor 2, effectively avoiding this risk.

[0097] Here, the gas-liquid separator 10 includes an air inlet end 10a and an air outlet end 10b; the compressor return air pipeline 41 includes a first return air pipeline 411 and a second return air pipeline 412; wherein the return air port 2a is connected to the air outlet end 10b via the first return air pipeline 411, and the air inlet end 10a is connected to the first node A via the second return air pipeline 412.

[0098] Exemplarily, the gas mixture (containing gaseous and possibly liquid refrigerants) first passes through the second return air line 412 and enters the gas-liquid separator 10 through the air inlet end 10a. The liquid refrigerant is recovered inside the gas-liquid separator 10, and the recovered gaseous refrigerant is transported to the return air port 2a of the compressor 2 through the first return air line 411 through the air outlet end 10a.

[0099] In some embodiments, please refer to Figure 2 , the refrigeration system also includes:

[0100] The pressure switch 7 and the valve 8 are connected via the signal line 11 , and the signal line 11 is used to transmit the control signal to the valve 8 .

[0101] It can be understood that the pressure switch 7 is used to obtain the pressure value of the return air port 2a, and determine whether the pressure value meets the set threshold, generate and send a control signal to the valve 8; the valve 8 is used to switch the working state based on the control signal, so that the refrigerant at the outlet 1b of the evaporator is output to the return air port 2a of the compressor 2 based on the throttling pipeline 9 and / or the first refrigerant pipeline 4. In order to realize the electrical signal communication between the pressure switch 7 and the valve 8, the pressure switch 7 and the valve 8 are connected via a signal line 11, and the signal line 11 is used to transmit the control signal.

[0102] In some embodiments, please refer to Figure 2 , the refrigeration system also includes:

[0103] The liquid storage tank 12 is arranged on the third refrigerant pipeline 6 near the outlet 3b of the condenser, and the liquid storage tank 12 includes a liquid inlet 12a and a liquid outlet 12b.

[0104] Here, the third refrigerant pipeline 6 includes a condenser output pipeline 61 and an evaporator input pipeline 62; wherein the condenser outlet 3b and the liquid inlet 12a are connected via the condenser output pipeline 61, and the liquid outlet 12b and the inlet 1a of the evaporator 1 are connected via the evaporator input pipeline 62.

[0105] It is understandable that the liquid storage tank 12 is mainly used to store excess liquid refrigerant coming out of the condenser 3 to ensure that when the system load changes, additional refrigerant can be provided or received in time to maintain the stable liquid supply required by the evaporator 1.

[0106] Exemplarily, the liquid refrigerant on the outlet 3b side of the condenser passes through the condenser output line 61 and enters the liquid storage tank 12 via the liquid inlet 12a. The liquid storage tank 12 separates the excess liquid refrigerant in the refrigerant to ensure that there is only liquid refrigerant. The liquid refrigerant passes through the liquid outlet 12b and the evaporator input line 62 and is output to the inlet 1a of the evaporator 1.

[0107] In some embodiments, please refer to Figure 2 , the refrigeration system also includes:

[0108] The drying filter 13 is arranged on the evaporator input pipeline 62 near the liquid outlet 12b.

[0109] It is understandable that even a trace amount of water in the refrigeration system will freeze at low temperatures, causing ice blockage, affecting the flow of refrigerant, and even damaging the equipment. The built-in desiccant (such as molecular sieve) in the drying filter 13 can effectively absorb the water in the refrigerant and keep the system dry.

[0110] In some embodiments, please refer to Figure 2 , the refrigeration system also includes:

[0111] The throttling device 14 is arranged on the evaporator input pipeline 62 near the inlet 1a side of the evaporator.

[0112] It can be understood that the throttling device 14 includes a thermal expansion valve and an electronic expansion valve, etc., which are used to adjust the refrigerant flow in the refrigeration system.

[0113] Here, the throttling device 14 ensures that the cooling capacity matches the current heat load by controlling the flow of liquid refrigerant entering the evaporator 1. When the heat load of the evaporator 1 increases, the throttling device 14 will automatically open wider to allow more refrigerant to flow into the evaporator 1; otherwise, the refrigerant flow rate will be reduced to maintain the high efficiency of the evaporation process.

[0114] In some embodiments, please refer to Figure 2 , the refrigeration system also includes:

[0115] The fourth refrigerant pipeline 15 is connected to the inlet 1b of the evaporator and the outlet 2b of the compressor 2; the defrost valve 16 is arranged on the fourth refrigerant pipeline 15 and is used to control the fourth refrigerant pipeline 15 to be turned on or off.

[0116] It is understandable that if the air conditioner is in defrost mode, the defrost valve 16 is usually activated (i.e., opened), so that the refrigerant can be directly returned from the outlet 2a of the compressor 2 to the inlet 1b side of the evaporator 1. In this way, by directly introducing the high-temperature and high-pressure refrigerant in the condenser 3 into the interior of the evaporator 1, the high temperature of the refrigerant can be used to accelerate the melting of frost on the surface of the evaporator 1, thereby improving the defrost efficiency.

[0117] It is understandable that if the air conditioner is in defrost mode, in order to accelerate defrosting, a large amount of liquid refrigerant may directly enter the evaporator 1, which will cause the mass flow rate of the refrigerant entering the evaporator 1 to exceed the normal range, affecting the evaporation efficiency and the refrigeration performance of the system. Excessive refrigerant may not be completely evaporated, further increasing the burden on the compressor 2 and may cause liquid hammer, damaging the compressor 2.

[0118] Here, when the air conditioner is in defrost mode, the pressure switch 7 can generate and send a control signal by obtaining the pressure value of the return air port 2a and determining that the pressure value meets the set threshold. The set threshold here is the pressure value corresponding to the abnormal pressure of the return air port 2a in the defrost mode. The valve 7 is used to switch the working state based on the control signal so that the refrigerant at the outlet of the evaporator 1 is output to the return air port 2a of the compressor 2 based on the throttling pipeline 9 and / or the first refrigerant pipeline 4, thereby avoiding the problems of excessive refrigerant flow and high suction back pressure in the defrost mode.

[0119] In some embodiments, the valve 8 is an electrically controlled valve, a gas controlled valve or a hydraulically controlled valve, and the valve 8 is used to close or reduce the opening based on a control signal.

[0120] It is understood that the electronically controlled valve controls its switch state or opening size through an electrical signal (such as voltage or current). The air-controlled valve uses compressed gas as the control medium and drives the valve action through changes in gas pressure. The hydraulically controlled valve uses liquid (such as hydraulic oil) to transmit power to operate the valve.

[0121] For example, if the valve 8 is a switch type valve, the switch type valve can only be switched between fully open and fully closed states, and cannot be adjusted in the middle, and is used to completely cut off or open the refrigerant flow path. When it is necessary to quickly stop or start the refrigerant circulation of a certain circuit, the control signal will instruct the valve 8 to be fully closed or fully opened. When fully closed, the refrigerant flow of the circuit is completely blocked and no longer participates in the circulation.

[0122] If the valve is adjustable in opening, such as the adjustable type of electric control valve, gas control valve or hydraulic control valve, its opening degree can be continuously adjusted from fully open to fully closed. The valve realizes continuous change of valve opening by receiving external control signals (such as voltage, air pressure or hydraulic signal). For example, when the cooling capacity needs to be reduced, the control system will send a signal to the valve, and the opening can be reduced to make it slightly closed, reducing the flow cross section, so that the amount of refrigerant flowing through will be reduced, thereby achieving its mass flow regulation function.

[0123] In some embodiments, please refer to Figure 2 , the refrigeration system also includes:

[0124] A first fan 17, the first fan 17 is arranged on the evaporator 1;

[0125] The second fan 18 is disposed on the condenser 3 .

[0126] It is understandable that the refrigeration system can enhance the heat exchange efficiency by adding the first fan 17 and the second fan 18. The first fan 17 is arranged on the evaporator 1, and its main function is to promote air to flow through the surface of the evaporator 1, thereby effectively absorbing heat in the air and evaporating the refrigerant inside the evaporator 1.

[0127] The second fan 18 is located on the condenser 3, and its function is to force air to flow through the heat sink of the condenser 3, helping to dissipate the heat released by the refrigerant during the condensation process to the surrounding environment. The use of the second fan 18 enhances the heat dissipation capacity of the condenser 3, ensures that the refrigerant can be effectively condensed, maintains the pressure stability on the high-pressure side of the system, and prepares to enter the evaporation process again.

[0128] The first fan 17 and the second fan 18 can enhance the heat exchange process in the refrigeration system, improve the efficiency in the evaporation and condensation stages respectively, ensure that the system can absorb and release heat quickly and effectively, and thus improve the overall refrigeration performance and energy efficiency.

[0129] The following describes an embodiment of the present application in detail with reference to an application example.

[0130] Please refer to Figure 2 In this application example, a pressure switch 7 is used to control a normally open electric valve 8, which changes from normally open to closed when the flow rate is large, allowing the refrigerant to pass through the throttling line 9 to reduce its mass flow rate; when the suction pressure drops to a critical value, the electric valve 8 is reopened, and the system passes through two branches (the first refrigerant line 4 and the throttling line 9) at the same time, and the system flow resistance is consistent with that without the added electric valve.

[0131] Therefore, compared with the KVL suction pressure regulating valve, this solution has the following advantages: 1) lower cost; 2) wider adaptability and smaller suction pressure loss; 3) new system components are simpler and more reliable.

[0132] In actual applications, when the refrigeration system is turned on at a high indoor ambient temperature or hot gas bypass is used for defrosting, the mass flow rate of the refrigerant will change greatly, and a high back pressure problem will also occur.

[0133] Based on this, in order to solve this problem, please refer to Figure 2 In this application example, the diameters of the compressor return air pipeline 41 and the valve control pipeline 41 can be represented by ΦD1, the evaporator output pipeline can be represented by ΦD2, and the diameter of the throttling pipeline 9 can be represented by ΦD3. Here, the relationship between them can be expressed as: ΦD1=0.9D2, ΦD3=0.5D1.

[0134] The working logic of this application example when the back pressure is high is as follows:

[0135] When the system pressure switch 7 detects that the return air pressure of the return air port 2a is higher than P1 (P1 can be set, tentatively set to 3.5Bar, and the setting range can be determined according to the actual power limit of the measured compressor 2), it indicates that the back pressure of the refrigeration system is too high, which may affect the normal operation and energy efficiency of the compressor 2. The electric valve 8 is controlled to close, and the main refrigerant of the refrigeration system flows from the throttling branch 9 into the gas-liquid separator 10, thereby reducing the suction back pressure and mass flow of the compressor 2, and finally reducing the refrigeration power of the compressor 2;

[0136] When the measured pressure of the return air port 2a is lower than P2 (P2 can be set, tentatively set to 2.3Bar, and the setting range can be determined according to the actual measured compressor power limit), it indicates that the system has returned to normal or low-load operation, and the electric valve 8 is reopened. The refrigerant flow path is restored, the electric valve 8 is controlled to open, and the main refrigerant of the system flows from the throttling branch 9 and the first refrigerant pipeline 4 into the gas-liquid separator 10, ensuring sufficient refrigerant flow to meet the current refrigeration demand and maintain the efficient operation of the system.

[0137] In this application example, in addition to the normally open electric valve, the valve in this application example can also be replaced by electric, pneumatic or other drive valves; the switch type valve can be replaced by an adjustable opening valve; the electric valve can be a pilot valve with negative feedback of other structural types.

[0138] In this way, by adopting the above-mentioned suction back pressure control scheme, the cost of the refrigeration system is lower; and when the system is in long-term operation, the system suction pressure loss is smaller, which can improve the theoretical energy efficiency coefficient of the refrigeration system; reduce the impact on the compressor motor and improve the reliability of key components.

[0139] It should be noted that the technical solutions described in the embodiments of the present application can be combined arbitrarily without conflict. The above are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A refrigeration system, characterized in that: The refrigeration system comprises: an evaporator, a condenser and a compressor connected via a refrigerant pipeline, wherein the outlet of the evaporator is connected to the return air port of the compressor via a first refrigerant pipeline, the outlet of the compressor is connected to the inlet of the condenser via a second refrigerant pipeline, and the outlet of the condenser is connected to the inlet of the evaporator via a third refrigerant pipeline; the refrigeration system also comprises: A pressure switch, the pressure switch is arranged on the first refrigerant pipeline near the return air port side, and is used to obtain the pressure value of the return air port, and determine whether the pressure value meets a set threshold, and generate and send a control signal; A valve, wherein the valve is arranged on the first refrigerant pipeline away from the return air port side; a throttling pipeline, the throttling pipeline being connected across two ends of the valve and being in communication with the first refrigerant pipeline, the throttling pipeline having a smaller diameter than the first refrigerant pipeline; The valve is used to switch the working state based on the control signal so that the refrigerant at the outlet of the evaporator is output to the return air port of the compressor based on the throttling pipeline and / or the first refrigerant pipeline.

2. The refrigeration system according to claim 1, characterized in that: The first refrigerant pipeline is provided with a first node close to the air return port side and a second node far from the air return port side, the first refrigerant pipeline includes a compressor air return pipeline, a valve control pipeline and an evaporator output pipeline, and the compressor air return pipeline, the valve control pipeline and the evaporator output pipeline are connected in sequence; The return air port and the first node are connected via the compressor return air pipeline; the first node and the second node are connected via the valve control pipeline, and the second node and the outlet of the evaporator are connected via the evaporator output pipeline; The pressure switch is arranged on the compressor return air pipeline, the valve is arranged on the valve control pipeline, and the throttling pipeline is connected across the two ends of the valve and communicated with the valve control pipeline; The diameter of the evaporator output pipeline is larger than the diameter of the valve control pipeline and the diameter of the compressor return pipeline.

3. The refrigeration system according to claim 2, characterized in that: The refrigeration system further comprises: A gas-liquid separator, the gas-liquid separator is arranged on the compressor return air pipeline, and is used to recover the liquid refrigerant in the compressor return air pipeline; The gas-liquid separator comprises an air inlet end and a air outlet end; The compressor return air pipeline includes a first return air pipeline and a second return air pipeline; The air return port is connected to the air outlet via the first air return pipeline, and the air inlet is connected to the first node via the second air return pipeline.

4. The refrigeration system according to claim 1, characterized in that: The refrigeration system further comprises: A signal line, the pressure switch and the valve are connected via the signal line, and the signal line is used to transmit the control signal to the valve.

5. The refrigeration system according to claim 1, characterized in that: The refrigeration system further comprises: A liquid storage tank, the liquid storage tank is arranged on the third refrigerant pipeline near the outlet side of the condenser, and the liquid storage tank includes a liquid inlet and a liquid outlet; The third refrigerant pipeline includes a condenser output pipeline and an evaporator input pipeline; The outlet of the condenser and the liquid inlet are connected via the condenser output pipeline, and the liquid outlet and the inlet of the evaporator are connected via the evaporator input pipeline.

6. The refrigeration system according to claim 5, characterized in that: The refrigeration system further comprises: A drying filter is arranged on the evaporator input pipeline close to the liquid outlet side.

7. The refrigeration system according to claim 5, characterized in that: The refrigeration system further comprises: A throttling device is arranged on the evaporator input pipeline close to the inlet side of the evaporator.

8. The refrigeration system according to claim 1, characterized in that: The refrigeration system further comprises: a fourth refrigerant pipeline, the fourth refrigerant pipeline being connected to an inlet of the evaporator and an outlet of the compressor; A defrost valve is provided on the fourth refrigerant pipeline and is used to control the fourth refrigerant pipeline to be turned on or off.

9. The refrigeration system according to claim 1, characterized in that: The valve is an electrically controlled valve, a pneumatically controlled valve or a hydraulically controlled valve, and the valve is used to close or reduce the opening based on the control signal.

10. The refrigeration system according to claim 1, characterized in that: The refrigeration system further comprises: a first fan, wherein the first fan is disposed on the evaporator; A second fan is arranged on the condenser.

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