Dual cycle air conditioning system

Abstract

This invention discloses a dual-cycle air conditioning system, including a first refrigeration circuit, a second refrigeration circuit, a first heat exchanger, and a second heat exchanger. The first refrigeration circuit includes a refrigerant pump, a first evaporator, and a first condenser. The second refrigeration circuit includes a compressor, a second throttling device, a second evaporator, and a second condenser. The first heat exchanger has a first low-temperature inlet, a first low-temperature outlet, a first high-temperature inlet, and a first high-temperature outlet respectively connected to the second evaporator, the compressor, the first condenser, and the refrigerant pump. The second heat exchanger has a second high-temperature inlet, a second high-temperature outlet, a second low-temperature inlet, and a second low-temperature outlet respectively connected to the second condenser, the second evaporator, the first evaporator, and the first condenser. The heat exchangers increase the subcooling of the refrigerant, reduce cavitation in the refrigerant pump, and increase the heat exchange capacity of the evaporator. Each circuit can operate independently or simultaneously to improve the overall system energy efficiency ratio.

Description

Technical Field

[0001] This application relates to the technical field of a refrigeration system, specifically a high-efficiency dual-cycle air conditioning system. Background Technology

[0002] Data center server rooms are widely used, and because they generate a lot of heat continuously, their air conditioning systems need to operate around the clock. Data shows that the power consumption of air conditioning systems in server rooms accounts for about 40% of the total power consumption of the server room, while in numerous base stations and modular offices, the power consumption of air conditioning systems can reach about 70% of the power consumption of the base station or modular office.

[0003] To reduce energy consumption, existing air conditioning systems mostly utilize natural cooling sources. For example, patent document CN104633815 B discloses an air conditioning system and its control method for computer rooms. This system connects a refrigerant pump in series with a traditional air conditioning system, and a control system uses relevant parameters to control the start and stop of the refrigerant pump and compressor to reduce energy consumption. However, this system suffers from problems such as inconvenient maintenance, severe cavitation of the refrigerant pump, and poor cooling performance, requiring further optimization. Summary of the Invention

[0004] This application provides a dual-cycle air conditioning system that improves the overall energy efficiency ratio of the system.

[0005] This application provides a dual-cycle air conditioning system, comprising:

[0006] The first refrigeration circuit includes a refrigerant pump, a first evaporator, and a first condenser;

[0007] The second refrigeration circuit includes a compressor, a second throttling device, a second evaporator, and a second condenser;

[0008] The first heat exchanger has a first low-temperature inlet, a first low-temperature outlet, a first high-temperature inlet, and a first high-temperature outlet, which are respectively connected to the second evaporator, the compressor, the first condenser, and the refrigerant pump.

[0009] The second heat exchanger has a second high-temperature inlet, a second high-temperature outlet, a second low-temperature inlet, and a second low-temperature outlet, which are respectively connected to the second condenser, the second evaporator, the first evaporator, and the first condenser.

[0010] Several alternative methods are provided below, but they are not intended as additional limitations on the overall solution above. They are merely further additions or optimizations. Provided there are no technical or logical contradictions, each alternative method can be combined individually with respect to the overall solution above, or multiple alternative methods can be combined with each other.

[0011] Optionally, the first refrigeration circuit includes a first throttling device disposed between the refrigerant pump and the first evaporator.

[0012] Optionally, the first refrigeration circuit includes a storage tank disposed between the refrigerant pump and the first heat exchanger.

[0013] Optionally, the refrigerant pump, storage tank, and first condenser are located outdoors.

[0014] Optionally, the first evaporator and the second evaporator may be located in the same space or in different spaces.

[0015] Optionally, depending on the gas flow direction, the first evaporator is located in the first space, and the second evaporator is located in the second space, with the gas passing through the first space before entering the second space.

[0016] Optionally, the refrigerant pump includes:

[0017] The outer shell has a liquid inlet and a liquid outlet, and the interior is provided with an inlet chamber and an outlet chamber that are respectively connected to the liquid inlet and the liquid outlet;

[0018] A volute, fixedly installed inside the outer shell, has a volute cavity that connects the liquid inlet chamber and the liquid outlet chamber and has an internal impeller;

[0019] A motor assembly, disposed in the liquid outlet chamber, includes an inner housing and an output shaft extending through the inner housing and connected to the impeller. The inner housing has a coolant inlet and a coolant outlet respectively communicating with the liquid outlet chamber and the volute chamber.

[0020] The inlet chamber, the volute chamber, and the outlet chamber are connected in sequence to form a first fluid channel; the outlet chamber, the inner shell, and the volute chamber are connected in sequence to form a second fluid channel.

[0021] Optionally, the inner housing has a first end and a second end, the first end having the coolant outlet.

[0022] Optionally, the output shaft extends out of the inner housing from the coolant outlet.

[0023] Optionally, the volute has an opening through which the output shaft passes, and the first end abuts against the volute and closes the opening.

[0024] Optionally, the volute has an inner liquid inlet located at the center and an inner liquid outlet extending from the volute cavity to the outer edge of the volute, and the coolant outlet and the inner liquid inlet are coaxially arranged.

[0025] Optionally, the front end of the output shaft extends to the inner liquid inlet.

[0026] The dual-cycle air conditioning refrigeration system of this application allows the refrigerant in both loops to increase its subcooling through the first and second heat exchangers. This helps reduce cavitation in the refrigerant pump and increases the heat exchange capacity of the subsequent evaporator, thereby improving the overall cooling capacity of the system. Furthermore, depending on changes in outdoor temperature, the first refrigeration loop can operate independently or the second refrigeration loop can operate simultaneously to improve the overall energy efficiency ratio of the system. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a dual-cycle air conditioning system according to an embodiment of this application;

[0028] Figure 2 This is an operating data table of a dual-cycle air conditioning system according to an embodiment of this application;

[0029] Figure 3 This is a schematic diagram of the modification of a conventional air conditioning system using the first refrigeration circuit according to an embodiment of this application;

[0030] Figure 4 This is a schematic diagram of the refrigerant pump of this application;

[0031] Figure 5 for Figure 4 A partial sectional view along the direction of the outer shell;

[0032] Figure 6 This is a schematic diagram of the motor assembly in a refrigerant pump according to an embodiment of this application;

[0033] Figure 7 This is a cross-sectional view of a refrigerant pump according to an embodiment of this application;

[0034] Figure 8 This is a partial exploded view of the motor assembly in a refrigerant pump according to an embodiment of this application;

[0035] Figure 9 This is a schematic diagram of the structure of the volute and motor assembly in a refrigerant pump according to an embodiment of this application;

[0036] Figure 10 This is a schematic diagram of the volute structure in a refrigerant pump according to an embodiment of this application;

[0037] Figure 11 This is a schematic diagram of the structure of the second inner end cover in a refrigerant pump according to an embodiment of this application;

[0038] Figure 12 This is a schematic diagram of the wiring cavity in a refrigerant pump according to an embodiment of this application.

[0039] The annotations in the figure are explained as follows:

[0040] 1000, First refrigeration circuit; 110, Refrigerant pump; 120, First evaporator; 130, First condenser; 140, First throttling device;

[0041] 2000, Second refrigeration circuit; 210, Compressor; 220, Second evaporator; 230, Second condenser; 240, Second throttling device

[0042] 310. First heat exchanger; 320. Second heat exchanger; 330. Storage tank; 400. Data center; 500. Fan;

[0043] 1. Outer shell; 11. Liquid inlet; 12. Liquid outlet; 13. Liquid inlet chamber; 14. Liquid outlet chamber; 15. Partition; 16. Auxiliary chamber;

[0044] 2. Volute; 21. Volute cavity; 22. Impeller; 221. Balance hole; 23. Opening; 231. Convex ring; 24. Inner inlet; 25. Inner outlet; 26. Sealing ring; 27. Impeller back cap;

[0045] 3. Motor assembly; 31. Inner housing; 311. Coolant inlet; 312. Coolant outlet; 313. First end; 314. Second end; 315. First inner end cover; 3151. Positioning step; 316. Second inner end cover; 317. Inner cylinder; 318. Stator; 32. Output shaft; 33. First bearing housing; 34. Lubrication hole; 35. Magnetic suction element; 36. Bearing; 37. Bearing; 38. Groove; 39. Through hole;

[0046] 4. Wiring terminals. Detailed Implementation

[0047] 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.

[0048] It should be noted that when a component is said to be "connected" to another component, it can be directly connected to the other component or it can be connected to a component in between. When a component is said to be "set on" another component, it can be directly set on the other component or it may be set to a component in between.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0050] In this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number or order of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0051] See Figure 1 This application provides a dual-cycle air conditioning system, including two independent refrigeration circuits, namely a first refrigeration circuit 1000 and a second refrigeration circuit 2000. The first refrigeration circuit 1000 includes a refrigerant pump 110, a first evaporator 120 and a first condenser 130, and the components are connected in sequence through pipelines to form a circuit. A first refrigerant circulates in the first refrigeration circuit 110.

[0052] The second refrigeration circuit 2000 includes a compressor 210, a second throttling device 240, a second evaporator 220, and a second condenser 230. The components are connected in sequence through pipes according to the arrows in the figure to form a circuit. A second refrigerant circulates in the second refrigeration circuit.

[0053] The dual-cycle air conditioning system also includes a first heat exchanger 310 and a second heat exchanger 320. The first heat exchanger 310 has a first low-temperature inlet, a first low-temperature outlet, a first high-temperature inlet, and a first high-temperature outlet, respectively connected to the second evaporator 220, the compressor 210, the first condenser 130, and the refrigerant pump 110. Here, high and low temperatures are defined based on the temperature ratio of the first refrigerant to the second refrigerant as it passes through the first heat exchanger. For example, if the temperature of the first refrigerant is higher than that of the second refrigerant, then the inlet and outlet connected to the first refrigeration circuit are considered high-temperature, and conversely, the inlet and outlet connected to the second refrigeration circuit are considered low-temperature.

[0054] The second heat exchanger 320 has a second high-temperature inlet, a second high-temperature outlet, a second low-temperature inlet, and a second low-temperature outlet, respectively connected to the second condenser 230, the second evaporator 220, the first evaporator 120, and the first condenser 130. The definitions of high and low temperatures are the same as those described above.

[0055] The first heat exchanger 310 can absorb heat from the first refrigerant by utilizing the temperature difference, thereby increasing the subcooling of the first refrigerant. This reduces the gas content in the first refrigerant, which helps to reduce cavitation in the refrigerant pump and improve its lifespan. Furthermore, it improves the efficiency of the refrigerant pump, increases the cooling capacity of the entire system, and thus improves the overall energy efficiency ratio of the entire system.

[0056] Similarly, the second heat exchanger 320 uses the temperature difference to absorb heat from the second refrigerant, increasing the subcooling of the second refrigerant, thereby increasing the cooling capacity of the second refrigeration circuit and improving the overall energy efficiency ratio of the entire system.

[0057] The two cooling circuits are independent of each other, allowing for maintenance of either circuit without affecting the other. The two circuits can be used independently or in combination, reducing compressor power consumption. The first cooling circuit utilizes the temperature difference between the outdoor and indoor environments to create a natural cold source, achieving low-power or even zero-power natural cooling. The dual-cycle design also allows for the retrofitting of existing data center air conditioning systems by adding the first cooling circuit to improve the overall energy efficiency ratio of the system.

[0058] The operating mode of the dual-cycle air conditioning system in this embodiment varies depending on the specific outdoor environment: for example, during low-temperature seasons, it can completely replace the compressor, i.e., the second cooling circuit stops working. During transitional seasons, the first cooling circuit pre-cools the data center, lowering the temperature to a certain level, before starting the second cooling circuit, thereby reducing the overall energy consumption of the entire air conditioning system and improving the comprehensive energy efficiency ratio.

[0059] For details, please refer to [link / reference]. Figure 2 This is a data table showing the performance of a dual-cycle air conditioning system installed in a data center with a power consumption of 40kW, operating in pure compressor mode and energy-saving hybrid mode using the dual-cycle air conditioning system described in this embodiment for a certain period of time. For example, as shown in the data table, when the outdoor temperature is -10 to -5 degrees Celsius, the comprehensive energy efficiency ratio of the energy-saving hybrid mode can reach 30.77, which is approximately four times that of the pure compressor mode.

[0060] In one embodiment, a first throttling device 140 is provided in the first refrigeration circuit 1000. The throttling device is used to throttle the medium-temperature and high-pressure liquid refrigerant into low-temperature and low-pressure wet vapor. The two ends of the first throttling device 140 are respectively connected to the refrigerant pump 110 and the first evaporator 120, wherein the throttling device is an expansion valve.

[0061] In one embodiment, the first refrigeration circuit 1000 includes a storage tank 330 disposed between the refrigerant pump 110 and the first heat exchanger 310. The storage tank 330 is used to perform gas-liquid separation on the first refrigerant entering the refrigerant pump 110, so that the liquefied first refrigerant sinks and is drawn away by the refrigerant pump 110, further reducing the cavitation phenomenon of the refrigerant pump. The floating gaseous first refrigerant is given time to liquefy. Preferably, the refrigerant pump 110, the storage tank 330 and the first condenser 130 are located outdoors, wherein the storage tank 330 can utilize an outdoor cold source to accelerate the liquefaction of the first refrigerant.

[0062] In one embodiment, the first evaporator 120 and the second evaporator 220 may be located in the same space or in different spaces. Specifically, the arrangement depends on space and environmental requirements; for example, in a spacious area, the first evaporator 120 and the second evaporator 220 can be arranged in the same space. For another example… Figure 3 According to the gas flow direction, the return air first passes through the space where the first evaporator 120 is arranged, then enters the space where the second evaporator 220 is arranged, and then enters the data center 400. An outdoor fan 500 is also installed, which can directly supply air to the space of the second evaporator 220 for cooling at a specific temperature. This scheme is the system modification described above. The first and second heat exchangers are omitted.

[0063] The specific control method is as follows: when the return air temperature detection value, i.e. the outdoor temperature detection value, is ≥ T1, the first refrigeration circuit starts to operate; when the return air temperature detection value, i.e. the outdoor temperature detection value, is ≥ T2 and the outdoor temperature is ≤ T3, the fresh air natural cooling energy-saving operation starts to operate; the above two operate according to independent logic to determine the operating conditions, and the values ​​(T1~T3) can be set or manually turned off. It also uses the set return air temperature to calculate the start and stop and load, and performs frequency conversion control.

[0064] The refrigerant pump can utilize existing technology or the following structure to further improve the cooling effect:

[0065] refer to Figures 4 to 5 This application provides a centrifugal refrigerant pump, mainly comprising a housing 1, a volute 2, and a motor assembly 3. The motor assembly 3 provides the input power for the centrifugal refrigerant pump. The housing 1 serves as the installation space for the volute 2, motor assembly 3, etc., and also acts as the outermost layer of the centrifugal refrigerant pump, providing insulation and protection from external elements. The impeller inside the volute 2 continuously rotates, drawing in liquid medium and using the centrifugal force of the impeller to transport the liquid medium, thus ensuring a continuous and stable flow rate. Furthermore, the liquid medium can be a conventional liquid refrigerant in the art.

[0066] The outer casing 1 has a liquid inlet 11 and a liquid outlet 12, such as Figure 4 The liquid medium shown enters through inlet 11 and exits through outlet 12. The internal space of the outer casing 1 is filled with the liquid medium. The outer casing 1 has an inlet chamber 13 and an outlet chamber 14, respectively connecting inlet 11 and outlet 12. This can be understood as the liquid medium entering inlet chamber 13 from inlet 11, then entering outlet chamber 14, and finally exiting from outlet 12; this constitutes an external delivery system. The inner wall of the outer casing 1 is the main pressure-bearing area, and its wall thickness can be increased according to the actual operating pressure requirements.

[0067] The volute 2 can be fixedly installed inside the outer casing 1 by screws or other fasteners. The volute 2 has a volute cavity 21 that connects the liquid inlet cavity 13 and the liquid outlet cavity 14. The volute cavity 21 has an impeller 22 inside. When the impeller 22 rotates continuously, a negative pressure is formed inside the volute cavity 21, so that the volute can continuously draw in the liquid medium in the liquid inlet cavity 13. Then, the liquid medium is discharged to the liquid outlet cavity 14 by the centrifugal force of the impeller. Compared with the gear pump pressurization method, the volute pressurization method significantly reduces the wear of parts and ensures that the flow rate of the liquid medium is always stable.

[0068] The motor assembly 3 is also installed inside the housing 1 and further disposed in the liquid outlet chamber 14. That is, when the centrifugal refrigerant pump is in normal operation, the motor assembly is surrounded by liquid medium. As the liquid medium is output from the liquid outlet 12, the heat generated by the motor assembly is also carried away. In other words, the centrifugal refrigerant pump does not need to set up a separate motor assembly cooling circuit to achieve excellent cooling effect.

[0069] Therefore, this application is completely different from existing gear pumps. The volute and motor assembly are entirely encased in liquid medium, and the outer casing completely isolates the volute and motor assembly from the external environment. This makes the internal working components insensitive to changes in external temperature and humidity, meaning that changes in external temperature and humidity will not affect the pump's operating performance or cause other damage that could affect its service life. Furthermore, by immersing the motor assembly in liquid medium, the original liquid medium delivery system also serves as the cooling circuit for the motor assembly, further simplifying the centrifugal refrigerant pump structure.

[0070] In some embodiments, the centrifugal refrigerant pump not only includes the outer casing 1, volute 2, and motor assembly 3 mentioned above, realizing the external delivery function, but also realizes the internal circulation of liquid medium by improving the structure of the internal motor assembly and volute.

[0071] refer to Figures 6 to 7 The motor assembly 3 of the centrifugal refrigerant pump includes an inner housing 31 and an output shaft 32. The inner housing 31 is relatively fixed and can be fixed in the liquid outlet chamber 14 by fasteners such as screws. The output shaft 32 is rotatably assembled in the inner housing 31, and one end of the output shaft 32 passes through the inner housing and is connected to the impeller drive, thereby continuously driving the impeller to rotate.

[0072] Motor assemblies generally consist of a stator and a rotor, with an assembly gap between them. In existing technologies, the stator and rotor are typically isolated within the motor assembly by installing additional insulating sleeves or applying insulating films. For example... Figure 6 The inner housing 31 can serve as the mounting base for the motor stator, and the output shaft 32 is the motor rotor. There is an assembly gap between the inner housing 31 and the output shaft 32. In this embodiment, this gap, i.e. the interior of the inner housing, is filled with a liquid medium to achieve the function of cooling and isolating the components.

[0073] The inner shell 31 serves not only as an independent installation space but also as an important component of the internal circulation channel, such as... Figure 7 As shown, the inner shell 31 is connected to the liquid outlet chamber 14 and the volute chamber 21 to form an internal circulation system. The inner shell 31 has a coolant inlet 311 connected to the liquid outlet chamber 14 and a coolant outlet 312 connected to the volute chamber 21. The liquid medium can enter from one end of the coolant inlet 311, flow through and fill the entire inner shell (i.e., the motor gap mentioned above), and then be discharged from the coolant outlet 312.

[0074] From the perspective of the liquid medium flow path, the centrifugal refrigerant pump has two internal fluid channels. The inlet chamber, the volute chamber, and the outlet chamber are sequentially connected to form the first fluid channel, and the outlet chamber, the inner shell, and the volute chamber are sequentially connected to form the second fluid channel. This enables simultaneous external transport and internal circulation of the liquid medium. Figure 7 As shown, the liquid medium enters the inlet chamber through the inlet port, passes through the inner inlet port and the inner outlet port in sequence, and then enters the outlet chamber. At this point, the liquid medium in the outlet chamber is divided. One part is discharged from the outlet port, completing the circulation of the liquid medium for external output. The other part enters the motor assembly from the coolant inlet, then passes through the coolant outlet, the volute, and the inner outlet port in sequence, returning to the outlet chamber. Thus, the liquid medium completes one internal circulation. This can also be understood as the other part of the liquid medium acting as coolant for the motor assembly, completing one cooling process within the motor assembly. The liquid medium directly carries away the heat generated by the motor assembly, preventing overheating and affecting the motor's lifespan. In addition, the liquid medium also serves to isolate the components within the motor assembly and provides lubrication.

[0075] Therefore, it can be seen that the motor assembly, impeller and other components in this embodiment are all installed in the outer casing, or even immersed in the liquid medium. The mechanical noise of the centrifugal refrigerant pump can be effectively isolated, resulting in low noise and vibration of the whole machine, or even close to a silent effect. It also has good protection and is not sensitive to changes in the external environment. Changes in external temperature and humidity will not affect the operation of the centrifugal refrigerant pump or cause other damage that affects its service life.

[0076] In addition, the centrifugal refrigerant pump delivers a stable and continuous flow rate through the volute pressurization. Combined with the two fluid channels inside the casing, most of the liquid medium is still delivered to ensure delivery efficiency, while only a small portion of the flow is used as coolant for the motor components. Each time the liquid medium is output to the outside, it also cools the motor components. The liquid medium directly carries away the heat generated by the motor components, thereby preventing the motor from overheating and extending its lifespan.

[0077] In some embodiments, the inner housing 31 has a first end 313 and a second end 314, each end performing a different function, such as... Figure 6 , Figure 8As shown, the coolant outlet is located at the first end, which is the only channel for the liquid medium in the inner shell to be discharged. That is, after the liquid medium enters the inner shell, it flows out only from the coolant outlet at the first end.

[0078] Correspondingly, the coolant outlet serves as the only outlet of the inner housing 31, and the output shaft 32 also extends out of the inner housing from the coolant outlet 312. The coolant outlet 312 can be equipped with a bearing 36 to support and rotatably connect the output shaft. When the liquid medium flows out from the coolant outlet, it also lubricates the bearing.

[0079] In some embodiments, reference Figure 9 , Figure 10 The volute 2 has an opening 23 for the output shaft to pass through, facilitating connection between the output shaft and the impeller drive. To make the internal structure more compact, the first end 313 abuts against the volute and closes the opening 23. This can be understood as the first end also serving as part of the inner wall of the volute cavity to seal it. The output shaft passes through the opening and connects to the impeller drive. A protruding ring 231 that mates with the first end can be provided at the opening to facilitate the installation and positioning of the first end. In addition, a sealing ring 26 can be provided at the abutment between the first end and the volute to prevent liquid medium from flowing out from the abutment gap, thus affecting the internal circulation efficiency of the liquid medium.

[0080] In some embodiments, the volute 2 is provided with an inner liquid inlet 24 located at the center and an inner liquid outlet 25 extending from the volute cavity 21 to the outer edge of the volute 2, such as Figure 7 As shown, the inner inlet 24 is positioned directly opposite the center of the impeller, and the inner outlet 25 extends in a direction tangent to the outline of the impeller. During the external circulation of the liquid medium, the liquid medium is drawn in through the inner inlet 24 and discharged from the inner outlet 25 under the centrifugal force of the impeller, entering the outlet chamber 14.

[0081] To ensure smoother internal circulation of the liquid medium, the connection between the vortex cavity and the coolant outlet is crucial. This ensures that all the liquid medium discharged from the coolant outlet can enter the vortex cavity. Figure 7 As shown, the coolant outlet and the internal inlet are coaxially arranged, meaning that the coolant outlet and the internal inlet are located at the center of both sides of the impeller. This allows the impeller to simultaneously draw in liquid media from both sides with each rotation, ensuring that the external and internal circulation of the liquid media are always synchronized. Each cycle of external liquid media delivery simultaneously cools and lubricates the internal components, guaranteeing the long-term stable operation of the centrifugal refrigerant pump.

[0082] In some embodiments, the volute and the inner wall of the outer shell are connected by a sealing ring to completely isolate the inlet and outlet chambers, preventing direct flow of liquid media between the two chambers.

[0083] In some embodiments, the front end of the output shaft extends to the inner inlet 24, such as... Figure 7 The front end shown can be equipped with an impeller back cap 27 to restrict the axial movement of the impeller. The impeller back cap 27 also extends to the inner liquid inlet 24. The front end of the output shaft also serves as a guide, further improving the impeller's conveying efficiency.

[0084] In some embodiments, corresponding to the first end which serves as the discharge channel, the second end 314 serves as the only inlet channel of the inner housing 31. The coolant inlet 311 is located at the second end, meaning that the liquid medium in the outlet chamber enters the inner housing 31 from the second end, flows through and fills the internal gap of the motor assembly, and is finally discharged entirely from the first end.

[0085] In some embodiments, the second end also serves to support the output shaft, such as... Figure 8 , Figure 11 As shown, the second end 314 is provided with a first bearing seat 33 and a lubrication hole 34 for conveying medium to the first bearing seat. The first bearing seat 33 is provided with a bearing 37 that rotates with the rear end of the output shaft 32. The lubrication hole 34 is positioned directly opposite the center of the first bearing seat 33, so that the liquid medium enters the inner housing 31 from the lubrication hole and lubricates the bearing at the same time.

[0086] In some embodiments, the second end 314 is provided with a magnetic suction element 35 for adsorbing iron filings. Since the bearing at the second end continuously rotates and engages with the output shaft, iron filings are easily generated after the bearing continuously wears down. Therefore, the magnetic suction element is used to adsorb iron filings in the liquid medium to prevent iron filings from remaining inside the motor assembly and affecting the normal operation of the motor assembly.

[0087] In some embodiments, such as Figure 8 As shown, the inner shell 31 includes an inner cylinder 317 and a first inner end cap 315 and a second inner end cap 316 that closes both ends of the inner cylinder. The inner cylinder 317 and the two inner end caps can be connected by a conventional plug-in structure, and a sealing ring can be provided at the connection to seal the connection gap.

[0088] The second inner end cover serves as the entry channel for the liquid medium in the inner shell, and the coolant inlet 311 is located on the second inner end cover; the first inner end cover serves as the only outlet channel for the liquid medium in the inner shell, and the coolant outlet 312 is located on the first inner end cover. The positions of the coolant inlet 311 and the coolant outlet 312 are arranged opposite to each other along the axial direction of the inner cylinder 317.

[0089] like Figure 9As shown, the first inner end cover may be provided with a positioning step 3151, which cooperates with the convex ring at the opening to ensure stable contact position; the coolant outlet is located at the center of the first inner end cover and coaxial with the inner inlet, and the coolant outlet and inner inlet are respectively located on both sides of the impeller. The impeller can be an open impeller, so that the impeller can simultaneously draw in liquid media from both sides with each rotation. In addition, balance holes 221 can be evenly distributed on the impeller, and the distance between the balance holes and the impeller axis is not greater than the radius of the coolant outlet, so as to better balance the axial forces on both sides of the impeller.

[0090] The coolant outlet 312 on the first inner end cover can also serve as a bearing housing. A bearing 36 can be installed on the coolant outlet 312 to support and rotatably connect the output shaft. When the liquid medium flows out from the coolant outlet, it also lubricates the bearing.

[0091] like Figure 11 As shown, the second inner end cover has multiple through holes 39 that can be used as coolant inlets 311, and the through holes are connected to the gap inside the motor assembly. After the liquid medium enters the inner housing through the multiple through holes, it quickly enters and fills the motor gap.

[0092] A groove 38 can be provided on the second inner end cover to serve as a first bearing seat 33. A bearing 37 that rotates with the rear end of the output shaft 32 is installed in the groove. Liquid medium can be stored inside the groove to lubricate the bearing.

[0093] A through lubrication hole 34 can be provided at the bottom of the groove. The lubrication hole 34 also serves as a coolant inlet 311. A portion of the liquid medium can enter the inner housing from the lubrication hole to cool the bearing and then participate in the internal circulation.

[0094] Because the liquid medium has a certain viscosity, it creates a liquid film on the bearing surface, achieving a self-lubricating effect. Compared with traditional lubricating oil lubrication, the lubrication method of this application can prevent the refrigerant and lubricating oil from dissolving together and affecting the heat exchange effect of the liquid medium.

[0095] Therefore, the bearing lubrication and motor assembly cooling circuit of this application is simple and reliable. The circuit is that the liquid medium in the outlet chamber passes through the coolant inlet 311 (i.e., bearing 36), the internal gap of the motor, and the coolant outlet 312 (i.e., bearing 37) to reach the volute. There is no need to design a separate lubrication and cooling structure. While maintaining long-term operation, it also effectively extends the service life of the bearing.

[0096] In some embodiments, reference Figure 12The centrifugal refrigerant pump also includes a terminal block 4 that is electrically connected to the motor assembly. A stator 318 is fixedly installed on the inner shell. A partition 15 can be installed inside the outer shell to form an auxiliary chamber 16 inside the outer shell. The auxiliary chamber 16 mainly facilitates the electrical connection between the stator of the motor assembly and the terminal block 4. The auxiliary chamber 16 is connected to the liquid outlet chamber. The auxiliary chamber 16 and the terminal block are sealed to prevent the liquid medium from leaking from the terminal block. Thus, the centrifugal refrigerant pump as a whole achieves full sealing and no leakage.

[0097] A through hole is provided at the center of the partition 15, and the outer shell and the partition 15 are fixedly connected by bolts, etc. Figure 12 As shown, the second end is bolted to the partition, and the assembly gap between the two can be adjusted by the bolt. The second end is partially covered by the partition, meaning that the liquid medium in the outlet chamber cannot directly enter the coolant inlet. It must first pass through the assembly gap to enter the coolant inlet. Therefore, the internal circulation flow rate of the liquid medium in this application is adjustable. Specifically, the adjustable assembly gap changes the flow rate of the liquid medium in the outlet chamber into the coolant inlet and auxiliary chamber, avoiding the internal circulation from affecting the external delivery efficiency and indirectly ensuring the delivery efficiency of the centrifugal refrigerant pump.

[0098] The dual-cycle air conditioning refrigeration system of this application allows the refrigerant in both loops to increase its subcooling through the first and second heat exchangers. This helps reduce cavitation in the refrigerant pump and increases the heat exchange capacity of the subsequent evaporator, thereby improving the overall cooling capacity of the system. Furthermore, depending on changes in outdoor temperature, the first refrigeration loop can operate independently or the second refrigeration loop can operate simultaneously to improve the overall energy efficiency ratio of the system.

[0099] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered to be within the scope of this specification. When technical features of different embodiments are embodied in the same drawing, it can be regarded as the drawing also disclosing examples of combinations of the various embodiments involved.

[0100] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are quite specific and detailed. However, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

Claims

1. A dual-circulation air conditioning system, characterized in that, include: The first refrigeration circuit includes a refrigerant pump, a first evaporator, and a first condenser; The second refrigeration circuit includes a compressor, a second throttling device, a second evaporator, and a second condenser; The first heat exchanger has a first low-temperature inlet, a first low-temperature outlet, a first high-temperature inlet, and a first high-temperature outlet, which are respectively connected to the second evaporator, the compressor, the first condenser, and the refrigerant pump. The second heat exchanger has a second high-temperature inlet, a second high-temperature outlet, a second low-temperature inlet, and a second low-temperature outlet, which are respectively connected to the second condenser, the second evaporator, the first evaporator, and the first condenser.

2. The dual-cycle air conditioning system according to claim 1, characterized in that, The first refrigeration circuit includes a first throttling device disposed between the refrigerant pump and the first evaporator.

3. The dual-cycle air conditioning system according to claim 1, characterized in that, The first refrigeration circuit includes a storage tank disposed between the refrigerant pump and the first heat exchanger.

4. The dual-cycle air conditioning system according to claim 3, characterized in that, The refrigerant pump, storage tank, and first condenser are located outdoors.

5. The dual-cycle air conditioning system according to claim 1, characterized in that, The refrigerant pump includes: The outer shell has a liquid inlet and a liquid outlet, and the interior is provided with an inlet chamber and an outlet chamber that are respectively connected to the liquid inlet and the liquid outlet; A volute, fixedly installed inside the outer shell, has a volute cavity that connects the liquid inlet chamber and the liquid outlet chamber and has an internal impeller; A motor assembly, disposed in the liquid outlet chamber, includes an inner housing and an output shaft extending through the inner housing and connected to the impeller. The inner housing has a coolant inlet and a coolant outlet respectively communicating with the liquid outlet chamber and the volute chamber. The inlet chamber, the volute chamber, and the outlet chamber are connected in sequence to form a first fluid channel; the outlet chamber, the inner shell, and the volute chamber are connected in sequence to form a second fluid channel.

6. The dual-cycle air conditioning system according to claim 5, characterized in that, The inner housing has a first end and a second end, the first end having the coolant outlet.

7. The dual-cycle air conditioning system according to claim 6, characterized in that, The output shaft extends out of the inner housing from the coolant outlet.

8. The dual-cycle air conditioning system according to claim 7, characterized in that, The volute has an opening through which the output shaft passes, and the first end abuts against the volute and closes the opening.

9. The dual-cycle air conditioning system according to claim 7, characterized in that, The volute has an inner liquid inlet located at the center and an inner liquid outlet extending from the volute cavity to the outer edge of the volute. The coolant outlet and the inner liquid inlet are coaxially arranged.

10. The dual-cycle air conditioning system according to claim 9, characterized in that, The front end of the output shaft extends to the internal liquid inlet.

Images