Refrigeration system with centralized economizer

Abstract

The utility model relates to refrigeration technical field discloses a refrigerating system with centralized economizer. The system includes: evaporimeter, multiple parallelly arranged compressor, liquid accumulator, centralized economizer is connected liquid accumulator through first pipeline, is connected evaporimeter through second pipeline, is connected first pipeline through third pipeline, and is connected compressor through fourth pipeline, control valve group contains parallelly arranged first expansion valve and second expansion valve, and corresponding first solenoid valve and second solenoid valve of drift diameter, and control unit according to refrigeration load parameter control valve group opening and closing and opening degree. When temperature and pressure sensor detect parameter fluctuation, real -time regulation valve group matching demand. Through adopting centralized economizer to replace multiple independent economizer, and combining the accurate regulation of control valve group and control unit, the system is simplified, and it is favorable to promote the liquid supply matching precision under the complex refrigeration load working condition.

Description

Technical Field

[0001] This utility model relates to the field of refrigeration technology, and in particular to a refrigeration system with a centralized economizer. Background Technology

[0002] In the refrigeration system of low-temperature cold storage, parallel compressor units are widely used, and each compressor is usually equipped with an independent economizer to achieve refrigerant subcooling and refrigerant replenishment cycle.

[0003] In related technologies, the configuration of multiple economizers results in a large number of components required for the refrigeration system, including economizers, expansion valves, and solenoid valves. This not only increases equipment procurement costs but also complicates piping design, increasing the difficulty of installation and maintenance. This is especially problematic for refrigeration units with limited space, making it difficult to achieve an efficient layout. Furthermore, the matching and adjustment of each independent economizer with the compressor relies on decentralized control, which can easily lead to inaccurate refrigerant supply issues when the refrigeration load fluctuates, affecting the energy efficiency and operational stability of the refrigeration system. Utility Model Content

[0004] This utility model discloses a refrigeration system with a centralized economizer, which can replace the independent economizer configured for each compressor by using a centralized economizer, reducing equipment procurement and installation costs, simplifying refrigeration system design, and solving layout problems in space-constrained environments. Furthermore, it can respond quickly to fluctuations in cooling load, ensuring the efficient and stable operation of the refrigeration system.

[0005] To achieve the above objectives, this application discloses a refrigeration system with a centralized economizer, comprising:

[0006] Evaporator;

[0007] Multiple compressors connected in parallel;

[0008] A liquid receiver, wherein the liquid receiver is connected to the evaporator via piping;

[0009] A centralized economizer is provided with a first liquid inlet, a first liquid outlet, a first air inlet, and a first air outlet. The first liquid inlet is connected to the liquid storage tank through a first pipe, the first liquid outlet is connected to the evaporator through a second pipe, the first air inlet is connected to the first pipe through a third pipe, and the first air outlet is connected to the multiple compressors arranged in parallel through a fourth pipe.

[0010] A control valve assembly, comprising a first solenoid valve, a second solenoid valve, a first expansion valve, and a second expansion valve, wherein the first solenoid valve and the second solenoid valve are connected in parallel on the third pipeline, and the first expansion valve and the second expansion valve are connected in parallel on the third pipeline, wherein the first expansion valve is located between the first solenoid valve and the first air inlet, and the second expansion valve is located between the second solenoid valve and the first air inlet.

[0011] The control unit is electrically connected to the control valve group. The control unit is used to control the opening and closing states of the first solenoid valve and the second solenoid valve, and to control the opening degree of the first expansion valve and the second expansion valve according to the load parameters of the refrigeration system.

[0012] As an optional implementation, the rated cooling capacity of the first expansion valve is greater than that of the second expansion valve, and the orifice of the first solenoid valve is greater than that of the second solenoid valve.

[0013] By using expansion valves and solenoid valves of different specifications, the system adapts to various refrigeration load scenarios. When the refrigeration system is operating with multiple compressors or under a large refrigeration load, the large-capacity first expansion valve and the large-diameter first solenoid valve ensure sufficient refrigerant supply. Conversely, when operating with a single compressor or under a smaller refrigeration load, the small-capacity second expansion valve and the small-diameter second solenoid valve precisely control the refrigerant supply. This tiered configuration improves the energy efficiency of the refrigeration system under different refrigeration loads, ensuring a dynamic match between refrigeration capacity and refrigeration load demand, thereby avoiding energy efficiency losses caused by insufficient or excessive refrigerant supply.

[0014] As an optional implementation, the rated cooling capacity of the first expansion valve is greater than or equal to 50kW, and the rated cooling capacity of the second expansion valve is less than or equal to 30kW; the diameter of the first solenoid valve is greater than or equal to 20mm, and the diameter of the second solenoid valve is less than or equal to 15mm.

[0015] By clearly defining the parameter ranges of the expansion valve and solenoid valve, the division of labor between the large and small valve groups becomes clearer. The large expansion valve and large solenoid valve can stably meet the refrigerant supply requirements of multiple compressors operating at full capacity or under high-power refrigeration load conditions, ensuring the refrigeration efficiency of the refrigeration system under high-power refrigeration load conditions; while the small expansion valve and small solenoid valve are suitable for single-unit or low-power refrigeration load conditions, avoiding excessive refrigerant supply and energy waste.

[0016] As an optional implementation, the refrigeration system includes a temperature sensor for collecting temperature parameters of the refrigerant, and the control unit is further used to control the opening degree of the first expansion valve and the second expansion valve, as well as the opening and closing state of the first solenoid valve and the second solenoid valve, based on the temperature parameters detected by the temperature sensor.

[0017] By installing a temperature sensor, the control unit receives real-time refrigerant temperature parameters, enabling it to adjust the expansion valve opening and solenoid valve operation based on actual temperature changes. For example, when fluctuations in the cold storage refrigeration load cause changes in refrigerant temperature, the temperature sensor detects this change and feeds it back to the control unit, which then adjusts the control valve assembly to adapt to the refrigeration load demand. This dynamic adjustment mechanism based on real-time temperature avoids the problem of refrigerant supply lag caused by manual adjustment, reduces energy efficiency losses due to temperature imbalances, ensures efficient operation of the refrigeration system even during temperature fluctuations, and thus improves stability under low-temperature conditions.

[0018] As an optional implementation, the refrigeration system further includes a pressure sensor for collecting refrigerant pressure parameters, and the control unit is further used to control the opening degree of the first expansion valve and the second expansion valve, as well as the opening and closing state of the first solenoid valve and the second solenoid valve, based on the pressure parameters detected by the pressure sensor.

[0019] By installing pressure sensors, the control unit can acquire pressure parameters of the refrigeration system, thereby reflecting the refrigerant flow status in the pipeline and changes in the refrigeration system load. This, along with temperature parameters, provides a more comprehensive basis for valve adjustment. The control unit combines this data with other parameters for comprehensive analysis, enabling a more accurate assessment of the refrigeration system's needs and avoiding potential deviations caused by adjusting only a single parameter. This multi-parameter adjustment mechanism improves the refrigeration system's responsiveness, further optimizes the accuracy of refrigerant supply control, reduces energy loss, and enhances the stability and energy efficiency of the refrigeration system under complex operating conditions.

[0020] As an optional implementation, the refrigeration system further includes shut-off valves, which are disposed on the first pipe, the second pipe, the third pipe, and the fourth pipe, and are used to open or close the fluid passage of the corresponding pipe.

[0021] Shut-off valves are installed on the first, second, third, and fourth pipes, allowing manual shut-off of fluid passages in the corresponding pipes when the refrigeration system requires maintenance, repair, or partial pipe shutdown. This design avoids the need for a complete system shutdown during maintenance, enabling independent shut-off of local pipes, reducing downtime and refrigeration interruption risks caused by maintenance, and thus improving the convenience of refrigeration system maintenance.

[0022] As an optional implementation, the refrigeration system further includes a sight glass, which is disposed on the pipeline between the first liquid outlet and the evaporator to observe the gas-liquid mixing state of the refrigerant flowing through the pipeline.

[0023] By placing a sight glass on the pipeline between the first liquid outlet and the evaporator, the refrigerant gas-liquid mixture flowing through the pipeline can be directly observed. This allows operators to promptly detect abnormalities in the refrigerant supply, such as refrigerant slugging, insufficient or excessive supply, preventing the escalation of the fault and subsequent equipment damage or energy efficiency degradation. This visual monitoring enhances the safety of the refrigeration system's operation, facilitates early warning and timely problem handling, reduces the risk of refrigeration system failure, and ensures stable refrigeration efficiency.

[0024] As an optional implementation, the refrigeration system further includes an oil separator and an oil cooler. The oil separator is connected to the oil cooler and the compressor, and the oil cooler is connected to the compressor. The oil separator is used to separate the lubricating oil discharged from the compressor, and the oil cooler is used to cool the lubricating oil separated by the oil separator and deliver it to the compressor.

[0025] An oil separator effectively separates the lubricating oil discharged from the compressor, preventing it from entering subsequent pipelines with the refrigerant and affecting heat exchange efficiency. It also prevents excessive lubrication loss, which could lead to insufficient compressor lubrication. The separated lubricating oil is cooled by an oil cooler and then returned to the compressor, lowering its temperature and preventing wear on internal compressor components from high-temperature lubricating oil. This extends the compressor's lifespan, reduces the probability of compressor failure due to poor lubrication or high temperatures, and ensures efficient compressor operation, thereby improving the stability of the entire refrigeration system.

[0026] As an optional implementation, the oil cooler is also connected to the condenser of the refrigeration system via a pipe, and the oil cooler also performs heat exchange on a portion of the refrigerant output from the condenser, with the heat-exchanged refrigerant flowing back into the condenser.

[0027] The oil cooler is connected to the condenser and utilizes a portion of the refrigerant for heat exchange. This allows the refrigerant to exchange heat upon entering the oil cooler, ensuring the lubricating oil returns to the compressor at a suitable temperature, reducing compressor wear. The refrigerant, after heat exchange, returns to the condenser to continue participating in the refrigeration system cycle, improving refrigerant utilization and avoiding resource waste. This design combines oil cooling with refrigerant circulation, improving the energy efficiency of the refrigeration system, ensuring stable compressor operation, and ultimately enhancing the overall energy efficiency of the refrigeration system.

[0028] As an optional implementation, the refrigeration system further includes a defrosting pipe, one end of which is connected to the oil separator and the other end of which is connected to the evaporator. The defrosting pipe is used to transport the gas in the oil separator to the evaporator to heat the evaporator.

[0029] The defrosting pipeline delivers high-temperature gas from the oil separator to the evaporator for heating and defrosting. Utilizing the high-temperature gas generated by the refrigeration system itself replaces the need for additional heating equipment, saving energy consumption required for defrosting. Heating the evaporator effectively removes surface frost, preventing excessive frost buildup from affecting the evaporator's heat exchange efficiency and ensuring stable refrigeration performance. This defrosting method does not require interrupting the refrigeration system's operation and can be completed without affecting the cold storage's cooling process. It reduces temperature fluctuations and energy losses caused by defrosting, thereby improving the refrigeration system's operational stability under low-temperature conditions.

[0030] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0031] The refrigeration system provided in this application replaces the individually configured economizers for each compressor with a centralized economizer. Combined with a staged expansion valve assembly and a solenoid valve assembly, it enables multiple compressors to share the refrigerant supply from a single economizer. This simplifies the refrigeration system design, reduces the number of key components such as economizers, expansion valves, and solenoid valves, and lowers equipment procurement and installation costs. Simultaneously, the centralized design saves installation space and solves layout challenges in space-constrained environments. Furthermore, by adjusting the staged expansion valve assembly and the solenoid valve assembly, under the control of the control unit, it ensures that the refrigerant supply accurately matches the compressor's needs under different refrigeration load scenarios, avoiding the refrigerant supply mismatch problem caused by the difficulty in coordinating multiple independent economizers. This improves the operating efficiency and stability of the entire parallel unit under complex operating conditions. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of a refrigeration system with a centralized economizer disclosed in an embodiment of this application;

[0034] Figure 2 yes Figure 1 Enlarged schematic diagram of point I in the middle;

[0035] Figure 3 yes Figure 1 Enlarged schematic diagram at point II;

[0036] Figure 4 yes Figure 1 Enlarged schematic diagram of section III.

[0037] Explanation of reference numerals in the attached figures:

[0038] Refrigeration system -100;

[0039] Evaporator-1; Multiple compressors connected in parallel-2; Liquid receiver-3;

[0040] Centralized economizer-4; First liquid inlet-41; First liquid outlet-42; First air inlet-43; First air outlet-44; First pipeline-45; Second pipeline-46; Third pipeline-47; Fourth pipeline-48; Shut-off valve-49;

[0041] Control valve assembly -5; First solenoid valve -51; Second solenoid valve -52; First expansion valve -53; Second expansion valve -54;

[0042] Control unit-6; Temperature sensor-7; Pressure sensor-8; Sight glass-9; Oil separator-10; Oil cooler-11; Condenser-12; Defrosting pipe-13. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] In this application, the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0045] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0046] Furthermore, the terms "installation," "setting," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0047] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0048] As described in the background section of this application, parallel compressor units are widely used in low-temperature cold storage refrigeration systems. Typically, each compressor is equipped with an independent economizer for refrigerant subcooling and refrigerant replenishment. However, this multi-economizer configuration requires a large number of components (such as economizers, expansion valves, and solenoid valves), increasing both equipment procurement and installation costs. It also complicates piping design, increasing installation and maintenance difficulties, especially in space-constrained refrigeration units where efficient layout is challenging. Furthermore, the reliance on decentralized control for each independent economizer makes them prone to inaccurate refrigerant supply during refrigeration load fluctuations, affecting the energy efficiency and operational stability of the refrigeration system.

[0049] Based on this, the present invention discloses a refrigeration system with a centralized economizer. By using a centralized economizer to replace multiple independent economizers, and combining precise adjustment of the control valve group and control unit, the cost is reduced, the refrigeration system is simplified, and the liquid supply matching accuracy under complex refrigeration load conditions is improved, thereby ensuring the efficient, stable and economical operation of the refrigeration system.

[0050] The technical solution of this application will be further described below with reference to specific embodiments and accompanying drawings.

[0051] Please see Figures 1 to 4 This is a schematic diagram of a refrigeration system 100 with a centralized economizer 4 disclosed in an embodiment of this application. The refrigeration system 100 includes: an evaporator 1, multiple compressors 2 connected in parallel, a liquid receiver 3, a centralized economizer 4, a control valve group 5, and a control unit 6.

[0052] The liquid receiver 3 is connected to the evaporator 1 via a pipe. The centralized economizer 4 is equipped with a first liquid inlet 41, a first liquid outlet 42, a first air inlet 43, and a first air outlet 44. The first liquid inlet 41 is connected to the liquid receiver 3 via a first pipe 45, the first liquid outlet 42 is connected to the evaporator 1 via a second pipe 46, the first air inlet 43 is connected to the first pipe 45 via a third pipe 47, and the first air outlet 44 is connected to multiple compressors 2 connected in parallel via a fourth pipe 48. The control valve group 5 includes a first solenoid valve 51, a second solenoid valve 52, a first expansion valve 53, and a second expansion valve 54. The first solenoid valve 51 and the second solenoid valve 52 are connected in parallel on the third pipe 47, and the first expansion valve 53 and the second expansion valve 54 are connected in parallel on the third pipe 47. The first expansion valve 53 is located between the first solenoid valve 51 and the first air inlet 43, and the second expansion valve 54 is located between the second solenoid valve 52 and the first air inlet 43. The control unit 6 is electrically connected to the control valve group 5. The control unit 6 is used to control the opening and closing states of the first solenoid valve 51 and the second solenoid valve 52, and to control the opening degree of the first expansion valve 53 and the second expansion valve 54 according to the refrigeration load parameters of the refrigeration system 100.

[0053] This refrigeration system 100 uses a centralized economizer 4 instead of the traditional independent economizers for each compressor, and achieves operation through integrated piping and control unit 6. The centralized economizer 4 constructs a complete cycle through four interfaces. The first liquid inlet 41 receives liquid refrigerant from the receiver 3, and after internal subcooling, it is sent to the evaporator 1 from the first liquid outlet 42 to enhance heat exchange efficiency. At the same time, the third pipe 47 branches off from the first pipe 45 to introduce a portion of refrigerant, which, after being regulated by the control valve group 5, enters the centralized economizer 4 from the first air inlet 43, and is then delivered to the gas supply port of multiple compressors 2 connected in parallel through the first air outlet 44 to achieve the gas supply function. The parallel design of the control valve group 5 can adapt to different refrigeration loads: for example, when multiple compressors 2 are running in parallel or when there is a high-power refrigeration load, the first expansion valve 53 and the second expansion valve 54 can be opened simultaneously as needed, or the rated refrigeration capacities of the first expansion valve 53 and the second expansion valve 54 can be different, and the expansion valve with the larger rated refrigeration capacity can be opened. Correspondingly, the diameters of the first solenoid valve 51 and the second solenoid valve 52 can also differ, allowing the solenoid valve with the larger diameter to be opened. When operating in a single unit or under low-power cooling load, the flow rate can be switched to the branch with a smaller flow rate, and the liquid supply can be precisely matched in conjunction with the dynamic control of the control unit 6.

[0054] This design offers three main advantages: First, it simplifies the structure of the refrigeration system 100, reducing the number of economizers, pipes, and auxiliary components, thereby lowering equipment procurement and installation costs and saving installation space, making it particularly suitable for unit layouts with limited space. Second, it improves control precision, as the control unit 6 adjusts the valve group status in real time based on refrigeration load parameters, avoiding the problem of mismatched liquid supply caused by independent compressor control. Third, it enhances operational stability, as the unified subcooling and gas replenishment functions of the centralized economizer 4 ensure consistent energy efficiency when multiple compressors 2 are running in parallel, thus maintaining high efficiency and stability even under complex operating conditions.

[0055] The aforementioned cooling load parameter refers to the cooling demand that the refrigeration system needs to handle per unit time, usually expressed as cooling capacity (unit kW).

[0056] It is understood that the above-mentioned centralized economizer 4 is particularly suitable for low-temperature operating conditions (below 5°C). Its internal structure can adopt a high-efficiency subcooling heat exchange channel or flash chamber design to enhance the subcooling of the refrigerant and the quality of the gas supply. This embodiment does not make specific limitations on this.

[0057] It is understood that the above-mentioned multiple compressors connected in parallel means two or more compressors connected in parallel, and this embodiment does not make a specific limitation on this.

[0058] In some embodiments, the rated cooling capacity of the first expansion valve 53 is different from that of the second expansion valve 54, and the through diameter of the first solenoid valve 51 is different from that of the second solenoid valve 52. Of course, in other embodiments, the rated cooling capacity of the first expansion valve 53 may be the same as that of the second expansion valve 54, and the through diameter of the first solenoid valve 51 may be the same as that of the second solenoid valve 52.

[0059] The following example illustrates the situation where the rated cooling capacity of the first expansion valve 53 is different from that of the second expansion valve 54, and the orifice diameter of the first solenoid valve 51 is different from that of the second solenoid valve 52.

[0060] In some embodiments, the rated cooling capacity of the first expansion valve 53 is greater than the rated cooling capacity of the second expansion valve 54, and the orifice of the first solenoid valve 51 is greater than the orifice of the second solenoid valve 52.

[0061] The first expansion valve 53, with a larger rated cooling capacity, can handle more refrigerant per unit time. Combined with the large-diameter first solenoid valve 51, it can quickly respond to refrigerant supply demands when multiple compressors 2 are running in parallel, ensuring sufficient refrigerant flow into the centralized economizer 4 and guaranteeing the subcooling effect of the economizer and the refrigerant supply to the multiple compressors 2. The second expansion valve 54, with a smaller rated cooling capacity, and the second solenoid valve 52, with a smaller diameter, are suitable for single-compressor operation. Their smaller flow adjustment range allows for more precise refrigerant supply control, preventing excessive refrigerant from entering the economizer and wasting energy. Therefore, in this application, the difference in rated cooling capacity between the first expansion valve 53 and the second expansion valve 54, and the difference in diameter between the first solenoid valve 51 and the second solenoid valve 52, are not simply parameter differences, but rather a precise matching design for the fluctuating characteristics of the system's cooling load. The difference in specifications creates a flow adjustment gradient, reducing the adjustment difficulty of the control unit 6, making the refrigerant supply match the demands of multiple compressors 2 in parallel more quickly and stably, further enhancing the operational stability of the refrigeration system 100 under complex operating conditions.

[0062] For example, when the cooling scenario is under a high-power cooling load (e.g., 1.1 to 1.3 times the rated power of the cooling system), multiple compressors 2 connected in parallel need to start simultaneously to meet the cooling demand. The control unit 6 will open the valve group corresponding to the first expansion valve 53 and the first solenoid valve 51, or open the parallel valve combination at the same time, so that the refrigerant can quickly enter the centralized economizer through the control valve group 5, flash into medium-pressure gas to replenish the multiple compressors 2 connected in parallel, and enhance the overall cooling capacity of the cooling system 100.

[0063] When the cooling scenario is under low-power cooling load (e.g., 0.6 to 0.8 times the rated power of the cooling system), only a single compressor needs to operate to maintain basic cooling. At this time, the control unit 6 can close the high-flow valve group branch and switch to the low-flow branch, activate or fine-tune the valve of the second expansion valve 54, and precisely control the refrigerant flow.

[0064] Therefore, this adjustment method in this application can ensure the stable operation of a single compressor, avoid the risk of liquid slugging in the compressor due to excessive refrigerant flow, and reduce energy consumption, achieving energy-saving operation. Through dynamic control of the control unit 6, this design can precisely match the refrigerant supply, ensuring that the refrigeration system 100 operates efficiently under different operating conditions.

[0065] In some embodiments, the rated cooling capacity of the first expansion valve 53 is greater than or equal to 50kW, and the rated cooling capacity of the second expansion valve 54 is less than or equal to 30kW; the orifice diameter of the first solenoid valve 51 is greater than or equal to 20mm, and the orifice diameter of the second solenoid valve 52 is less than or equal to 15mm. Thus, the first expansion valve 53 and the first solenoid valve 51 can form a large-scale valve group, and the second expansion valve 54 and the second solenoid valve 52 can form a small-scale valve group. Therefore, the control unit can control the operation of either the large-scale or small-scale valve group according to the cooling load of the refrigeration system 100.

[0066] Understandably, the rated cooling capacity of the first expansion valve can be 50kW, 60kW, 80kW, or 100kW, etc. The rated cooling capacity of the second expansion valve can be 30kW, 20kW, or 10kW, etc. The orifice of the first solenoid valve can be 20mm, 25mm, 30mm, or 35mm, etc. The orifice of the second solenoid valve can be 15mm, 10mm, or 5mm, etc.

[0067] In some embodiments, such as Figure 1 and Figure 2 As shown, the refrigeration system 100 includes a temperature sensor 7, which is used to collect real-time temperature parameters of the refrigerant and control the opening degree of the first expansion valve 53 and the second expansion valve 54, as well as the opening and closing state of the first solenoid valve 51 and the second solenoid valve 52.

[0068] This application provides real-time data support for the regulation of the refrigeration system 100 by adding a temperature sensor 7, thereby further improving the control accuracy of the control unit 6.

[0069] Understandably, the temperature sensor 7 can be installed at key nodes of the refrigeration system 100, such as the outlet of the evaporator 1, the first liquid outlet 42 of the centralized economizer 4, the suction port of the compressor, or inside the cold storage. The temperature parameters at these locations can directly reflect the heat exchange status of the refrigerant and changes in the system's refrigeration load. For example, the outlet temperature of the evaporator 1 can reflect the heat exchange efficiency, and the suction port temperature of the compressor can reflect the gas replenishment effect.

[0070] For example, when temperature sensor 7 is placed at the outlet of evaporator 1, the refrigerant temperature will change accordingly when the refrigeration load of the cold storage fluctuates. For instance, if the cold storage temperature rises, the refrigerant temperature at the outlet of evaporator 1 will increase. At this time, temperature sensor 7 can detect this temperature change and feed it back to control unit 6. Thus, control unit 6 can determine that the refrigeration system 100 is in a state of increased refrigeration load, and can control to increase the opening of the expansion valve or open the high-flow solenoid valve to increase the refrigerant flow into the centralized economizer 4, thereby enhancing the subcooling and gas replenishment effects. Conversely, if the cold storage temperature drops, temperature sensor 7 can also detect this temperature change and feed it back to control unit 6. Thus, control unit 6 can determine that the refrigeration system 100 is in a state of decreased refrigeration load, and can control to decrease the opening of the expansion valve and open the low-flow solenoid valve to avoid energy waste caused by excessive refrigerant supply. This dynamic adjustment based on real-time temperature allows the control valve assembly 5 to adjust synchronously with the refrigeration load changes of the refrigeration system 100, effectively reducing the loss of refrigeration capacity caused by temperature imbalance.

[0071] In some embodiments, such as Figure 1 and Figure 2 As shown, the refrigeration system 100 also includes a pressure sensor 8, which is used to collect the pressure parameters of the refrigerant. The control unit 6 is also used to control the opening degree of the first expansion valve 53 and the second expansion valve 54, as well as the opening and closing state of the first solenoid valve 51 and the second solenoid valve 52, according to the pressure parameters detected by the pressure sensor 8.

[0072] Specifically, this embodiment further improves the accuracy of the refrigeration system 100 control by adding a pressure sensor 8. The pressure sensor 8 can be installed at key pipeline nodes of the refrigeration system 100, such as the first inlet 43 and the first outlet 44 of the centralized economizer 4, the suction port or discharge port of the compressor, etc., to collect real-time pressure parameters of the refrigerant. These parameters can directly reflect the flow state of the refrigerant in the pipeline (such as flow rate and resistance changes) and the changes in the refrigeration load of the refrigeration system 100 (such as fluctuations in condensing pressure and evaporating pressure).

[0073] For example, when pressure sensor 8 is placed at the discharge port of multiple compressors 2 connected in parallel, the refrigerant discharge pressure will change accordingly with the changes in the operating conditions of the refrigeration system 100. For instance, if the refrigeration load of the cold storage increases, compressor 2 needs to increase its refrigeration capacity to maintain the low temperature. At this time, the operating frequency of compressor 2 will increase, and the discharge volume will increase. Pressure sensor 8 detects the increase in discharge pressure and simultaneously feeds back the situation to the control unit. The control unit 6 determines that the refrigeration system 100 is in a high-power refrigeration load state based on the feedback from the pressure sensor, and then controls the first solenoid valve 51 to open and the first expansion valve 53 to increase the opening degree, so as to increase the refrigerant flow from the first pipe 45 through the third pipe 47 into the centralized economizer 4. This ensures that the centralized economizer 4 can provide sufficient gas replenishment for multiple compressors 2 connected in parallel, and at the same time enhances the subcooling effect on the main cycle refrigerant to match the refrigeration demand under high-power refrigeration load, and avoids the continuous increase in discharge pressure due to insufficient liquid supply, which would increase the energy consumption of the compressor.

[0074] When the refrigeration system 100 is running, the pressure sensor 8 and the temperature sensor 7 work synchronously and jointly participate in the decision-making of the control unit 6, so that the control unit 6 can make more accurate judgments on the state of the refrigeration system 100. In complex scenarios such as drastic fluctuations in refrigeration load and low temperature conditions, the valve group state can be adjusted more quickly and accurately, reducing energy efficiency loss caused by control deviation.

[0075] In some embodiments, such as Figure 1 and Figure 2 As shown, the refrigeration system 100 also includes a shut-off valve 49, which is disposed on the first pipe 45, the second pipe 46, the third pipe 47 and the fourth pipe 48. The shut-off valve is used to open or close the fluid passage of the corresponding pipe.

[0076] By installing shut-off valves 49 on the first pipe 45, second pipe 46, third pipe 47, and fourth pipe 48, each pipe can be independently opened or closed. For example, when the centralized economizer 4 needs maintenance, the shut-off valves 49 on the first pipe 45 and the third pipe 47 can be closed to cut off the refrigerant supply from the receiver 3 to the economizer and the refrigerant input to the branch pipes. At the same time, the shut-off valve 49 on the fourth pipe 48 can be closed to prevent refrigerant backflow on the gas supply side, thus isolating the economizer from the main body of the refrigeration system 100. If the evaporator 1 needs maintenance, the shut-off valve 49 on the second pipe 46 can be closed to isolate the evaporator 1 area separately, without affecting the normal operation of the economizer and the multiple compressors 2 connected in parallel. By independently shutting down local pipes, the downtime of the refrigeration system 100 is shortened, which is especially suitable for scenarios requiring continuous refrigeration and reduces the risks caused by refrigeration interruption. At the same time, the shut-off function of the shut-off valves 49 can quickly cut off the faulty area in the event of a pipe leak, reducing the amount of refrigerant loss and minimizing environmental impact and material loss. In addition, for complex refrigeration systems 100 with multiple compressors in parallel, some pipelines can be flexibly shut off by the shut-off valve 49 to achieve segmented commissioning or refrigeration load adjustment of the refrigeration system 100, thereby improving the convenience and flexibility of operation.

[0077] In some embodiments, such as Figure 1 and Figure 2 As shown, the refrigeration system 100 also includes a sight glass 9, which is disposed on the pipeline between the first liquid outlet 42 and the evaporator 1 to observe the gas-liquid mixing state of the refrigerant flowing through the pipeline.

[0078] By placing the sight glass 9 on the pipeline between the first liquid outlet 42 of the centralized economizer 4 and the evaporator 1, a critical pipeline is established for delivering the liquid refrigerant, after subcooling by the economizer, to the evaporator 1. The gas-liquid mixing state of the refrigerant at this location directly reflects the subcooling effect and liquid supply stability of the economizer. Under normal operating conditions, the refrigerant flowing through this pipeline should be in a subcooled liquid state. If a large number of bubbles, liquid slugging, or turbidity are observed, it indicates an abnormality in the refrigeration system 100. Through this intuitive monitoring, staff can address the problem in its early stages, preventing minor issues from escalating into equipment damage, such as compressor failure or long-term energy efficiency degradation due to liquid slugging, thereby reducing the risk of refrigeration system 100 failure.

[0079] Please refer to the following: Figures 1 to 4 In some embodiments, the refrigeration system 100 further includes an oil separator 10 and an oil cooler 11. The oil separator 10 is connected by pipes to the oil cooler 11 and multiple compressors 2 connected in parallel, and the oil cooler 11 is also connected by pipes to the multiple compressors 2 connected in parallel. The oil separator 10 is used to separate the lubricating oil discharged by the multiple compressors 2 connected in parallel, and the oil cooler 11 is used to cool the lubricating oil separated by the oil separator 10 and deliver it to the multiple compressors 2 connected in parallel.

[0080] The oil separator 10 is connected via a pipeline to the discharge end of multiple compressors 2 arranged in parallel and to the oil cooler 11. Its function is to separate the refrigerant and lubricating oil mixture discharged from the multiple compressors 2. When the multiple compressors 2 are running, the lubricating oil is discharged along with the refrigerant. If it directly enters heat exchange components such as the condenser 12 and evaporator 1, it will form an oil film on the heat exchange surface, reducing heat exchange efficiency. At the same time, excessive loss of lubricating oil will lead to insufficient lubrication of the internal components of the multiple compressors 2 arranged in parallel, thereby aggravating wear. Based on this, the oil separator 10 of this application separates the lubricating oil in the mixture through an internal structure (such as a baffle, filter screen or centrifugal separation device), which can effectively separate refrigerant and lubricating oil, so that the separated lubricating oil can be transported to the oil cooler 11 through a pipeline.

[0081] The oil cooler 11 connects the oil separator 10 to multiple compressors 2 connected in parallel. Its function is to cool the separated lubricating oil. The lubricating oil discharged from the multiple compressors 2 is typically at a high temperature due to mechanical friction and the high-temperature environment. If it were directly returned to the compressors 2, the lubricating performance of the high-temperature lubricating oil would decrease, and it would also exacerbate the thermal wear of internal components. The oil cooler 11 cools the lubricating oil to a suitable range (usually matching the compressor operating temperature) through heat exchange, and then returns the cooled lubricating oil to the lubrication points of the multiple compressors 2, ensuring stable lubrication. In this way, the impact of lubricating oil on heat exchange components can be reduced, maintaining efficient heat exchange in the evaporator 1 and condenser 12; reducing maintenance costs due to frequent lubricating oil replenishment; and for the refrigeration system 100 with multiple compressors 2 connected in parallel, unified lubricating oil management can reduce lubrication differences between compressors, thereby ensuring consistent unit operation.

[0082] In some embodiments, the oil cooler 11 is also connected to the condenser 12 of the refrigeration system 100 via a pipe. The oil cooler 11 also performs heat exchange on a portion of the refrigerant output from the condenser 12, and the refrigerant after heat exchange flows back into the condenser 12.

[0083] Specifically, the oil cooler 11 draws a portion of the refrigerant from the condenser 12 through a pipe and introduces it into its own heat exchange chamber. At this time, the high-temperature lubricating oil delivered by the oil separator 10 also enters the heat exchange chamber of the oil cooler 11. The two media exchange heat through the heat exchange walls within the chamber: the high-temperature lubricating oil transfers heat to the low-temperature refrigerant, causing the lubricating oil to flow back to the multiple parallel compressors 2; while the refrigerant, having absorbed heat, experiences a temperature increase and returns to the condenser 12 through the return pipe to continue participating in the condensation cycle of the refrigeration system 100. The advantage of this design is that it eliminates the need for additional electric heating or independent cooling equipment, directly utilizing the waste heat of the refrigerant output from the condenser 12 to cool the lubricating oil, reducing the additional energy consumption of the refrigeration system 100. Simultaneously, the refrigerant participating in the heat exchange is not consumed but flows back to the condenser 12 to re-enter the cycle, ensuring not only the oil cooling effect but also avoiding refrigerant waste, thereby improving refrigerant utilization. Furthermore, for the refrigeration system 100 with multiple compressors 2 connected in parallel, this centralized oil cooling method can adapt to the lubricating oil cooling requirements under different operating refrigeration loads by flexibly adjusting the refrigerant flow rate, thereby further improving the reliability of the refrigeration system 100.

[0084] In some embodiments, the refrigeration system 100 further includes a defrosting conduit 13, one end of which is connected to the oil separator 10 and the other end of which is connected to the evaporator 1. The defrosting conduit 13 is used to transport the gas in the oil separator 10 to the evaporator 1 to heat the evaporator 1.

[0085] Specifically, the defrosting pipe 13 transports the high-temperature gas from the oil separator 10 to the evaporator 1 for heating and defrosting. This utilizes the high-temperature gas generated by the refrigeration system 100 itself, replacing additional heating equipment and saving energy consumption required for defrosting. Heating the evaporator 1 effectively removes surface frost, preventing excessive frost buildup from affecting the heat exchange efficiency of the evaporator 1 and ensuring stable cooling performance of the refrigeration system 100. This defrosting method does not require interrupting the operation of the refrigeration system 100 and can complete the defrosting operation without affecting the cold storage's cooling capacity. It reduces temperature fluctuations and energy losses caused by defrosting, and improves the operational stability of the refrigeration system 100 under low-temperature conditions.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A refrigeration system having a centralized economizer, comprising: The refrigeration system includes: Evaporator; Multiple compressors connected in parallel; A liquid receiver, wherein the liquid receiver is connected to the evaporator via piping; A centralized economizer is provided with a first liquid inlet, a first liquid outlet, a first air inlet, and a first air outlet. The first liquid inlet is connected to the liquid storage tank through a first pipe, the first liquid outlet is connected to the evaporator through a second pipe, the first air inlet is connected to the first pipe through a third pipe, and the first air outlet is connected to the multiple compressors arranged in parallel through a fourth pipe. A control valve assembly, comprising a first solenoid valve, a second solenoid valve, a first expansion valve, and a second expansion valve, wherein the first solenoid valve and the second solenoid valve are connected in parallel on the third pipeline, and the first expansion valve and the second expansion valve are connected in parallel on the third pipeline, wherein the first expansion valve is located between the first solenoid valve and the first air inlet, and the second expansion valve is located between the second solenoid valve and the first air inlet. The control unit is electrically connected to the control valve group. The control unit is used to control the opening and closing states of the first solenoid valve and the second solenoid valve, and to control the opening degree of the first expansion valve and the second expansion valve according to the load parameters of the refrigeration system.

2. The refrigeration system of claim 1, wherein, The rated cooling capacity of the first expansion valve is greater than that of the second expansion valve, and the orifice of the first solenoid valve is greater than that of the second solenoid valve.

3. The refrigeration system of claim 2, wherein, The rated cooling capacity of the first expansion valve is greater than or equal to 50kW, and the rated cooling capacity of the second expansion valve is less than or equal to 30kW. The first solenoid valve has a diameter greater than or equal to 20 mm, and the second solenoid valve has a diameter less than or equal to 15 mm.

4. The refrigeration system of claim 1, wherein, The refrigeration system includes a temperature sensor for collecting temperature parameters of the refrigerant. The control unit is also used to control the opening degree of the first expansion valve and the second expansion valve, as well as the opening and closing state of the first solenoid valve and the second solenoid valve, based on the temperature parameters detected by the temperature sensor.

5. The refrigeration system of claim 1, wherein, The refrigeration system also includes a pressure sensor, which is used to collect the pressure parameters of the refrigerant. The control unit is also used to control the opening degree of the first expansion valve and the second expansion valve, as well as the opening and closing state of the first solenoid valve and the second solenoid valve, based on the pressure parameters detected by the pressure sensor.

6. The refrigeration system of claim 1, wherein, The refrigeration system also includes shut-off valves, which are installed on the first, second, third, and fourth pipes. The shut-off valves are used to open or close the fluid passage of the corresponding pipes.

7. The refrigeration system of claim 6, wherein, The refrigeration system also includes a sight glass, which is installed on the pipeline between the first liquid outlet and the evaporator to observe the gas-liquid mixing state of the refrigerant flowing through the pipeline.

8. The refrigeration system of any of claims 1-7, wherein, The refrigeration system also includes an oil separator and an oil cooler. The oil separator is connected to the oil cooler and the compressor, and the oil cooler is connected to the compressor. The oil separator is used to separate the lubricating oil discharged from the compressor, and the oil cooler is used to cool the lubricating oil separated by the oil separator and deliver it to the compressor.

9. The refrigeration system of claim 8, wherein, The oil cooler is also connected to the condenser of the refrigeration system via a pipe. The oil cooler also exchanges heat with a portion of the refrigerant output from the condenser, and the refrigerant after heat exchange flows back into the condenser.

10. The refrigeration system of claim 8, wherein, The refrigeration system also includes a defrosting pipe, one end of which is connected to the oil separator and the other end of which is connected to the evaporator. The defrosting pipe is used to transport the gas in the oil separator to the evaporator to heat the evaporator.

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