Air conditioning system

Abstract

The invention provides an air conditioning system. The air conditioning system comprises a two-stage compressor, a first condenser, an evaporator, a liquid storage tank, a first pump and a second condenser. The evaporator is connected to the first condenser through an expansion valve, the evaporator is further connected to the first-stage compressor, the evaporator is used for converting refrigerant liquid into refrigerant gas, and the refrigerant gas discharged by the evaporator is conveyed to the first-stage compressor; the liquid storage tank is used for storing refrigerant liquid; the first pump is connected to the liquid storage tank and a motor of the two-stage compressor, and is used for supplying the refrigerant liquid in the liquid storage tank to the motor of the two-stage compressor; the second condenser is connected to a motor of the two-stage compressor and the liquid storage tank, and the second condenser is used for receiving refrigerant liquid and / or refrigerant gas discharged by the motor of the two-stage compressor, condensing the refrigerant gas discharged by the motor into the refrigerant liquid and providing the refrigerant liquid to the liquid storage tank.

Description

Technical Field

[0001] The present disclosure relates to an air-conditioning system, and belongs to the technical field of air-conditioning. Background Art

[0002] Heat pump systems are widely used to recover waste heat from production and daily life, and are crucial for energy conservation and emission reduction. Generally speaking, a heat pump system uses a compressor to heat and pressure the refrigerant gas generated by heat exchange with waste heat. The high-temperature, high-pressure refrigerant then exchanges heat with water on the user side, generating high-temperature water to meet the high-temperature water needs of production and daily life. Compared to conventional electric heating, heat pump systems can save up to 80% in electricity. To further enhance energy savings, the compressor is driven by a variable-frequency, high-speed permanent magnet motor. Furthermore, to prevent refrigerant leakage, the compressor is generally enclosed.

[0003] Existing compressors typically consist of a high-speed permanent magnet motor and an impeller. The motor is centered, flanked by compressor impellers. The motor's rotor assembly is supported by bearings on either side. These bearings not only support the weight of the rotor assembly but also absorb the axial forces generated by the compressor impeller. Magnetic and air bearings are commonly used in these high-speed permanent magnet motors. Under high evaporation and condensation conditions, existing technologies are unable to effectively reduce the temperature within the motor cavity, leading to compressor failure. Summary of the Invention

[0004] The present disclosure provides an air conditioning system.

[0005] According to one aspect of the present disclosure, there is provided an air conditioning system comprising: A two-stage compressor, the two-stage compressor comprising a first-stage compressor and a second-stage compressor; a first condenser connected to the second-stage compressor, the first condenser being configured to condense at least a portion of the high-temperature and high-pressure refrigerant gas discharged from the second-stage compressor into a refrigerant liquid; an evaporator, the evaporator being connected to the first condenser via an expansion valve and further connected to the first-stage compressor, the evaporator being configured to convert refrigerant liquid into refrigerant gas, and the refrigerant gas discharged from the evaporator being delivered to the first-stage compressor; A liquid storage tank, the liquid storage tank is used to store refrigerant liquid; a first pump connected to the liquid storage tank and the motor of the two-stage compressor and configured to supply refrigerant liquid in the liquid storage tank to the motor of the two-stage compressor; and The second condenser is connected to the motor of the two-stage compressor and the liquid storage tank. The second condenser is used to receive the refrigerant liquid and / or refrigerant gas discharged by the motor of the two-stage compressor, condense the refrigerant gas discharged by the motor into refrigerant liquid, and provide the refrigerant liquid to the liquid storage tank.

[0006] According to the air conditioning system of at least one embodiment of the present disclosure, the evaporator is connected to the inlet side of the first pump via a first pipeline, wherein a first switching valve is provided on the first pipeline.

[0007] According to the air conditioning system of at least one embodiment of the present disclosure, the liquid storage tank is further connected to the evaporator via a second pipeline, wherein a second pump and a second switching valve are provided on the second pipeline.

[0008] According to at least one embodiment of the present disclosure, the air conditioning system further includes: A supply tank is used to store refrigerant liquid, and the supply tank is connected to the liquid storage tank through a third pipeline, wherein a third switching valve and a third pump are provided on the third pipeline; wherein the supply tank is used to provide refrigerant liquid to the bearings of the motor of the two-stage compressor.

[0009] According to the air conditioning system of at least one embodiment of the present disclosure, the refrigerant liquid supplied to the bearing of the motor of the two-stage compressor flows through the bearing of the motor and is then discharged to the second condenser.

[0010] According to the air conditioning system of at least one embodiment of the present disclosure, the bearing of the motor of the two-stage compressor is disposed on a bearing seat, and the bearing seat is cooled by cold source water.

[0011] According to the air-conditioning system of at least one embodiment of the present disclosure, an annular accommodating cavity is formed on the bearing seat, and the annular accommodating cavity is respectively connected to the cold source water inlet and the cold source water outlet. The cold source water inlet is used to provide cold source water into the annular accommodating cavity, and the cold source water outlet is used to discharge the cold source water in the annular accommodating cavity to the outside of the motor.

[0012] According to the air conditioning system of at least one embodiment of the present disclosure, the evaporator is further configured to receive heat source water, and the temperature of the heat source water is reduced after flowing through the evaporator.

[0013] According to the air conditioning system of at least one embodiment of the present disclosure, the first condenser is further configured to receive service water, and the temperature of the service water is increased after flowing through the first condenser.

[0014] According to at least one embodiment of the air conditioning system of the present disclosure, a liquid level gauge is provided in the liquid storage tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings illustrate exemplary embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure. These drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification.

[0016] Figure 1 Schematic diagram of the structure of an air conditioning system according to one embodiment of the present disclosure.

[0017] Figure 2 2 is a schematic structural diagram of an air conditioning system according to another embodiment of the present disclosure.

[0018] Figure 3 1 is a schematic structural diagram of a two-stage compressor according to one embodiment of the present disclosure.

[0019] The specific reference numerals in the figure are: 100 Two-stage compressor 110 Motor 111 Chassis 112 first bearing seat 113 Second bearing seat 114 motor shaft 115 rotor parts 116 stator components 117 baffle 120 First impeller 130 Second impeller 140 First volute 150 Second volute 200 First Condenser 300 evaporator 400 fluid storage tank 500 First Pump 600 Second Condenser 610 First switch valve 620 Second Pump 630 Second switch valve 700 supply tank 710 Third switch valve 720 Third Pump 740 Fourth switch valve. DETAILED DESCRIPTION

[0020] The present disclosure will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to explain the relevant content and are not intended to limit the present disclosure. It should also be noted that, for ease of description, only the portions relevant to the present disclosure are shown in the accompanying drawings.

[0021] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in the present disclosure can be combined with each other. The technical solution of the present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0022] Unless otherwise stated, the exemplary embodiments / examples shown are to be understood as providing exemplary features of various details of some ways in which the technical concepts of the present disclosure can be implemented in practice. Therefore, unless otherwise stated, the features of the various embodiments / examples may be further combined, separated, interchanged, and / or rearranged without departing from the technical concepts of the present disclosure.

[0023] The use of cross hatching and / or shading in the accompanying drawings is generally used to make the boundaries between adjacent components clear. As such, unless otherwise indicated, the presence or absence of cross hatching or shading does not convey or indicate any preference or requirement for the specific materials, material properties, dimensions, proportions, commonalities between the components shown, and / or any other characteristics, attributes, properties, etc. of the components. In addition, in the accompanying drawings, the sizes and relative sizes of the components may be exaggerated for clarity and / or descriptive purposes. When the exemplary embodiments can be implemented differently, the specific process sequence can be performed in a different order than described. For example, two successively described processes can be performed substantially simultaneously or in an order opposite to the order described. In addition, the same figure numbers represent the same components.

[0024] When a component is referred to as being “on,” “over,” “connected to,” or “coupled to” another component, the component may be directly on, directly connected to, or directly coupled to the other component, or intervening components may be present. However, when a component is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another component, there are no intervening components present. For this purpose, the term “connected” may refer to a physical connection, an electrical connection, etc., with or without intervening components.

[0025] For descriptive purposes, the present disclosure may use spatially relative terms such as "below," "beneath," "under," "down," "above," "upper," "above," "higher," and "side (e.g., as in "sidewall")," to describe the relationship of one component to another (other) component as shown in the accompanying drawings. The spatially relative terms are intended to encompass different orientations of the device in use, operation, and / or manufacture in addition to the orientation depicted in the accompanying drawings. For example, if the device in the drawings is turned over, a component described as "below" or "beneath" another component or feature would then be positioned "above" the other component or feature. Thus, the exemplary term "below" can encompass both the "above" and "below" orientations. Furthermore, the device may be otherwise oriented (e.g., rotated 90 degrees or at other orientations), and as such, the spatially relative descriptors used herein should be interpreted accordingly.

[0026] The terms used herein are for the purpose of describing specific embodiments and are not intended to be restrictive. As used herein, unless the context clearly indicates otherwise, the singular forms "one (kind, person)" and "said (the)" are also intended to include plural forms. In addition, when the terms "comprise" and / or "include" and their variations are used in this specification, the features, integral bodies, steps, operations, parts, assemblies and / or their groups stated are explained, but the presence or addition of one or more other features, integral bodies, steps, operations, parts, assemblies and / or their groups is not excluded. It should also be noted that, as used herein, the terms "substantially", "approximately" and other similar terms are used as approximate terms and not as degree terms, so that they are used to explain the inherent deviations of the measured values, calculated values ​​and / or the values ​​provided that will be recognized by those of ordinary skill in the art.

[0027] Figure 1 Schematic diagram of the structure of an air conditioning system according to one embodiment of the present disclosure.

[0028] like Figure 1 As shown, the air conditioning system of the present disclosure may include components such as a two-stage compressor 100 , a first condenser 200 , an evaporator 300 , a liquid storage tank 400 , a first pump 500 , and a second condenser 600 .

[0029] The two-stage compressor 100 includes a first-stage compressor and a second-stage compressor. The first-stage compressor receives the refrigerant gas discharged from the evaporator 300 and performs a first-stage compression on the refrigerant gas. The refrigerant gas compressed in the first stage enters the second-stage compressor and is further compressed by the second-stage compressor to produce high-temperature, high-pressure refrigerant gas.

[0030] The first condenser 200 is connected to the second-stage compressor and is configured to condense at least a portion of the high-temperature, high-pressure refrigerant gas discharged from the second-stage compressor into a refrigerant liquid. In a preferred embodiment, the first condenser 200 is also configured to receive service water, which is heated after passing through the first condenser 200.

[0031] In other words, the working water and the refrigerant can exchange heat in the first condenser 200, so that the heat released when the high-temperature and high-pressure refrigerant gas is converted into the refrigerant liquid can be used to heat the working water, and the temperature of the working water can be increased from about 70° to above 75°, so that the heat in the working water can be recycled to save energy.

[0032] The evaporator 300 is connected to the first condenser 200 via an expansion valve and is also connected to the first-stage compressor. The evaporator 300 is used to convert refrigerant liquid into refrigerant gas. The refrigerant gas discharged from the evaporator 300 is delivered to the first-stage compressor.

[0033] Specifically, after the high-temperature refrigerant liquid flows out of the first condenser 200, part of the refrigerant liquid will be converted into refrigerant gas through the expansion effect of the expansion valve. At this time, the high-temperature refrigerant liquid will become a mixture of low-temperature refrigerant liquid and refrigerant gas.

[0034] The low-temperature mixture of refrigerant liquid and refrigerant gas enters the evaporator 300 and is evaporated by the evaporator 300 to provide cooling to the outside through the evaporator 300 .

[0035] In a preferred embodiment, the evaporator 300 also receives heat source water, which is cooled after flowing through the evaporator 300. In other words, the evaporator 300 of the present disclosure not only provides cooling but also recovers heat from the heat source water. For example, if the heat source water entering the evaporator 300 is approximately 50°C, the temperature of the heat source water flowing out of the evaporator 300 can be reduced to below 45°C, thereby utilizing the heat in the heat source water (low-temperature hot water).

[0036] The liquid storage tank 400 of the present disclosure is used to store refrigerant liquid; this refrigerant liquid can be used to cool the motor of the two-stage compressor. In other words, in the air conditioning system of the present disclosure, the provision of the liquid storage tank 400 enables the motor to be cooled by an independent circuit, thereby improving the cooling effect of the motor.

[0037] Specifically, compared with the prior art solution of providing refrigerant liquid from a condenser or an economizer to the motor, the temperature of the motor of the present disclosure can be further reduced.

[0038] For example, the temperature inside the motor cavity (or motor temperature) in the prior art is generally around 110°C, while the temperature inside the motor cavity (or motor temperature) of the present invention is below 80°C, thereby increasing the service life of the motor.

[0039] The first pump 500 is connected to the liquid storage tank 400 and the motor of the two-stage compressor 100, and is used to provide the refrigerant liquid in the liquid storage tank 400 to the motor of the two-stage compressor 100; specifically, the first pump 500 of the present disclosure can provide the refrigerant liquid to the inner cavity of the motor of the two-stage compressor 100, and at this time the refrigerant liquid can cool the stator component, rotor component and other components of the motor.

[0040] The second condenser 600 of the present invention is connected to the motor of the two-stage compressor 100 and the liquid storage tank 400. The second condenser 600 is used to receive the refrigerant liquid and / or refrigerant gas discharged by the motor of the two-stage compressor 100, and condense the refrigerant gas discharged by the motor into refrigerant liquid, and provide the refrigerant liquid to the liquid storage tank 400.

[0041] That is, when the refrigerant liquid is supplied to the motor cavity, it cools the stator and rotor components of the motor. At this point, at least a portion of the refrigerant liquid is converted into refrigerant gas. Alternatively, some refrigerant liquid may not be converted into refrigerant gas, and a mixture of refrigerant gas and refrigerant liquid may be discharged from the motor cavity into the second condenser 600.

[0042] The second condenser 600 is also used to receive condensed water with a lower temperature, so as to reduce the temperature and liquefy the mixture of refrigerant liquid and refrigerant gas as quickly as possible, thereby forming an independent path for cooling the motor.

[0043] In the present disclosure, the liquid storage tank 400 and the second condenser are both located at the bottom of the evaporator 300. A liquid level gauge is provided in the liquid storage tank 400 to detect whether the level of the refrigerant liquid in the liquid storage tank 400 meets the requirements. If the refrigerant liquid in the liquid storage tank 400 is low, some refrigerant liquid can be taken out from the evaporator 300 and replenished in the liquid storage tank 400.

[0044] Specifically, the evaporator 300 is connected to the inlet side of the first pump 500 via a first pipeline, wherein a first on-off valve 610 is disposed on the first pipeline. In a preferred embodiment, the first on-off valve 610 may be a ball valve. When the first on-off valve 610 is opened and the cold source water flows through the second condenser, the refrigerant liquid in the evaporator 300 will flow from the evaporator 300 to the liquid storage tank 400 to a set liquid level due to gravity and / or the pressure difference between the evaporator and the second condenser. At this time, the first on-off valve 610 is closed.

[0045] Considering that impellers are connected to both ends of the motor, high-temperature and high-pressure refrigerant gas flows in the impellers. Part of this refrigerant gas will pass through the sealing structure of the motor and flow into the inner cavity of the motor. Therefore, when the two-stage compressor works for a long time, the refrigerant liquid in the liquid storage tank 400 will increase. At this time, these liquids need to be discharged.

[0046] Specifically, when the liquid level gauge detects a high level of refrigerant liquid in the liquid storage tank 400, the refrigerant liquid in the liquid storage tank 400 can be discharged to the evaporator 300. At this point, the liquid storage tank 400 is also connected to the evaporator 300 via a second pipeline, wherein the second pipeline is provided with a second pump 620 and a second on-off valve 630. Thus, when the second pump 620 is in operation and the second on-off valve 630 is open, the second pump 620 can pump refrigerant liquid from the liquid storage tank 400, pressurize the refrigerant liquid, and deliver it to the evaporator 300.

[0047] Figure 2 2 is a schematic structural diagram of an air conditioning system according to another embodiment of the present disclosure.

[0048] like Figure 2 As shown, the air-conditioning system of the present invention also includes a supply tank 700, which is used to store refrigerant liquid. The supply tank 700 is connected to the liquid storage tank 400 through a third pipeline, wherein a third switching valve 710 and a third pump 720 are provided on the third pipeline; wherein the supply tank 700 is used to provide refrigerant liquid to the bearings of the motor of the two-stage compressor 100.

[0049] At this time, the bearings of the motor are air-floating bearings. Accordingly, the refrigerant liquid provided to the bearings not only supports the motor shaft but also cools the bearings.

[0050] The refrigerant liquid provided to the bearings of the motor of the two-stage compressor 100 flows through the bearings of the motor into the motor cavity and is discharged to the second condenser 600; that is, the motor of the two-stage compressor 100 disclosed in the present invention has only one refrigerant liquid / refrigerant gas discharge port. At this time, the refrigerant liquid and / or refrigerant gas flowing through the bearings can enter the motor cavity, and flow out to the outside of the motor through the holes opened on the casing, and further flow to the second condenser 600.

[0051] In other words, the refrigerant liquid in the liquid storage tank 400 of the present invention can be pumped to the supply tank 700 via the third pump 720; the supply tank 700 can be connected to the bearing of the motor through a fourth pipeline, and a fourth switch valve 740 can be provided on the fourth pipeline. The fourth switch valve 740 can be a ball valve. Thus, when the third pump 720 is in working state and the third switch valve 710 and the fourth switch valve 740 are in open state, the supply tank 700 can provide refrigerant liquid to the bearing of the motor.

[0052] In addition, an electric heater and a temperature sensor can be provided in the supply tank 700. At this time, when the third pump 720 is in a non-working state and the third switch valve 710 is in a closed state, the refrigerant liquid in the supply tank 700 can be heated by the electric heater, and at least part of the refrigerant liquid can be converted into refrigerant gas. At this time, the pressure in the supply tank 700 will increase, and the refrigerant liquid will be transported to the bearings of the motor through this pressure.

[0053] At this time, when the refrigerant liquid in the supply tank 700 is low, the third pump 720 can be controlled to be in an operating state and the third switch valve 710 can be controlled to be open, thereby replenishing the refrigerant liquid into the supply tank 700.

[0054] Figure 3 1 is a schematic structural diagram of a two-stage compressor according to one embodiment of the present disclosure.

[0055] like Figure 3 As shown, the two-stage compressor 100 of the present disclosure includes a motor 110 and a first impeller 120 and a second impeller 130 driven by the motor 110; the motor 110 includes a housing 111, which is a cylindrical structure, with a first bearing seat 112 and a second bearing seat 113 fixed at both ends thereof; one end of the motor shaft 114 of the motor 110 is rotatably disposed in the first bearing seat 112 through a first bearing, and similarly, the other end of the motor shaft 114 is rotatably disposed in the second bearing seat 113 through a second bearing. The first bearing and the second bearing can be any type of oil-free bearings. In a specific embodiment, the first bearing and the second bearing can be air-floating bearings, and one of the first bearing and the second bearing can be radial-axial, and the other of the first bearing and the second bearing can be a composite bearing of a radial bearing and a thrust bearing.

[0056] Specifically, the housing 111 of the present invention and the first bearing seat 112 and the second bearing seat 113 provided at both ends of the housing 111 can form an inner cavity of the motor. At this time, the stator component and the rotor component of the motor are all provided in the inner cavity of the motor.

[0057] In the present disclosure, a rotor component 115 is disposed on the motor shaft 114, and a stator component 116 is fixed to the housing 111. Specifically, an annular groove is provided on the inner wall of the housing 111. This groove is located approximately in the middle of the rotor component 115 along the axis of the motor 110. The stator component 116 can be fixed to the housing 111 and at least partially covers the annular groove. More preferably, a through hole is provided in the side wall of the annular groove, thereby allowing refrigerant liquid to flow through the through hole to the outside of the annular groove and further to the rotor component 115.

[0058] Furthermore, a first storage space is formed between one sidewall portion of the annular groove and the first bearing seat 112, while a second storage space is formed between the other sidewall portion of the annular groove and the second bearing seat. In other words, a first storage space and a second storage space are formed on either side of the annular groove, respectively. Refrigerant liquid can be stored in each of the first and second storage spaces, and both ends of the stator component 116 can extend into the first and second storage spaces, respectively, and come into contact with the refrigerant liquid within the first and second storage spaces.

[0059] The housing 111 of the present disclosure is provided with a refrigerant inlet, which can be communicated with the annular groove, so that the refrigerant liquid can be provided into the annular groove. Figure 3 Although not shown, those skilled in the art should know that a refrigerant outlet is provided on the casing 111 , and the refrigerant outlet can be communicated with the second condenser 600 .

[0060] In a preferred embodiment, the refrigerant outlet is connected to the second storage space. In this case, the liquid in the first storage space will flow into the second storage space and be discharged through the refrigerant outlet. Specifically, the stator component 116 can be formed with multiple flow channels, through which the refrigerant liquid will flow from the first storage space to the second storage space and then be discharged from the motor. Accordingly, the flow of the refrigerant liquid can cool the stator core and enameled wire, etc., thereby reducing the temperature of the stator component.

[0061] The first bearing seat 112 and the second bearing seat 113 of the present disclosure can be cooled by cold water. Specifically, an annular accommodating cavity is formed on each of the first bearing seat 112 and the second bearing seat 113. The annular accommodating cavity is connected to a cold water inlet and a cold water outlet, respectively. The cold water inlet is used to provide cold water into the annular accommodating cavity, and the cold water outlet is used to discharge the cold water in the annular accommodating cavity to the outside of the motor.

[0062] In a specific embodiment, the annular accommodating cavities of the first bearing seat 112 and the second bearing seat 113 are formed in the same manner. Taking the first bearing seat 112 as an example, a groove opening toward the interior of the motor is formed on the first bearing seat 112. This groove can be covered by a baffle 117, thereby forming the annular accommodating cavity. In this case, the baffle 117 can form at least a portion of the sidewall of the first accommodating space or the second accommodating space.

[0063] The first volute 140 is fixed to the first bearing seat 112 and is used to accommodate the first impeller. Similarly, the second volute 150 is fixed to the second bearing seat 113 and is used to accommodate the second impeller.

[0064] Based on this structure, the motor of the disclosed air conditioning system is independently cooled. The temperature within the motor cavity is independent of waste heat and the user-side temperature, ensuring that the motor operates at a relatively low temperature. This prevents demagnetization of the rotor components and the permanent magnets of the magnetic bearings, as well as high-temperature aging of the winding insulation. Furthermore, this air conditioning system can improve the heat pump system's cycle efficiency by over 6%.

[0065] In the existing technology, refrigerant liquid is generally supplied to the motor through a condenser or economizer. At this time, the temperature in the inner cavity of the motor corresponds to the saturation pressure in the cavity, which is equal to the saturation pressure in the evaporator plus the pressure loss in the pipeline from the inner cavity of the motor to the evaporator. Under high evaporation and high condensation conditions, the density of the suction gas and the compression ratio increase, the power consumption and heat generation of the motor increase sharply, the temperature in the motor cavity exceeds 80°C, and the temperature of the motor winding can reach 120~140°C, far exceeding the 100~110°C under normal conditions, causing the aging of the insulation material and the risk of demagnetization of the permanent magnets of the permanent magnet motor rotor components and magnetic bearings. To solve this technical problem, the solution in the existing technology is to replace the permanent magnet material, but this will increase costs and weaken the competitiveness of the product.

[0066] On the other hand, as the water temperature on the user side rises, the curvature of the working fluid's two-phase line changes. Given the same pressure rise (although the pressure ratio decreases), a large amount of refrigerant liquid is decompressed and vaporized by the expansion valve, leaving only a portion of low-temperature liquid for motor cooling. To ensure effective motor cooling, a large amount of liquid must be diverted from the condenser. The compressor then needs to recompress this gas, which has no heat transfer capacity, consuming a large amount of compression power and significantly reducing system energy efficiency. Using an economizer and diverting motor cooling liquid from the economizer not only improves system circulation efficiency but also reduces cooling liquid usage. However, this does not solve the motor cooling problem when the waste heat source temperature rises.

[0067] Therefore, under high evaporation and high condensation conditions, how to reduce the temperature in the motor cavity and improve the circulation efficiency of the heat pump system is a bottleneck problem in the application of high-temperature heat pumps.

[0068] Compared with the existing technology, that is, compared with the solution of providing refrigerant liquid to the motor through a condenser or economizer, the air-conditioning system disclosed in the present invention can solve the cooling problem of the motor under high evaporation and high condensation conditions, so that the temperature of the motor winding and permanent magnet is controlled below 80°C (H-level insulation safety range), providing a reliable thermal management solution for the compressor, and at the same time improving the circulation efficiency of the high-temperature heat pump system.

[0069] In other words, the refrigerant liquid provided to the motor can be a supercooled working fluid liquid, thereby condensing the superheated gas in the motor cavity through the supercooled working fluid liquid, and the generated saturated liquid is cooled in the second condenser using an external cold source to produce a supercooled working fluid liquid, which is further pressurized by the first pump to increase the degree of supercooling.

[0070] In the present disclosure, the second condenser can be a liquid-liquid heat exchanger, where an external cooling source exchanges heat with the saturated liquid working fluid discharged from the motor, lowering the working fluid's temperature. The saturation temperature of the second condenser determines the temperature of the motor cavity. The lower the external cooling source temperature, the lower the motor cavity temperature. The external cooling source temperature must be lower than the temperature of the waste heat source water. Thus, the air conditioning system of the present disclosure decouples the motor cavity temperature from the evaporation and condensation temperatures of the heat pump system.

[0071] The liquid storage tank disclosed herein is used to store liquid working medium (i.e., refrigerant liquid) and provide liquid to the inlets of the first pump, the second pump, and the third pump. In an optional embodiment, the liquid storage tank can be a liquid bag at the bottom of the second condenser.

[0072] The first pump is used to increase the pressure of the liquid working fluid, overcome pressure losses in the cooling circuit, deliver the low-temperature working fluid to the motor cavity, and further increase the subcooling of the working fluid. In a preferred embodiment, the first pump can be a variable frequency pump, which can control its speed based on the temperature of the motor cavity, increasing its speed when the temperature in the motor cavity exceeds a set value, and vice versa. When the first pump is a fixed frequency pump, the cold source water pump that provides cold source water to the second condenser is a variable frequency pump, and this cold source water pump also controls its speed based on the temperature of the motor cavity.

[0073] Based on the above structure, unlike the prior art which can only condense the temperature of the motor cavity (or the motor temperature) to about 110°C and is not suitable for high evaporation and high condensation working conditions, the air-conditioning system disclosed in the present invention can use supercooled liquid to condense the superheated gas in the motor cavity to achieve motor cooling, thereby being able to control the temperature of the motor cavity (or the motor temperature) at 80°C, and the temperature of the motor cavity is not related to the working conditions of the heat pump (i.e., the first condenser and the evaporator).

[0074] In other words, the existing technology uses a high-temperature and high-pressure working fluid to produce gas and liquid after being decompressed by an expansion valve, and the temperature of the gas and liquid is the saturation temperature in the motor cavity, that is, saturated liquid is used to cool the superheated gas in the motor cavity; however, in the air-conditioning system disclosed in the present invention, the temperature in the motor cavity can be effectively reduced through an independent cooling circuit.

[0075] Existing methods that use high-temperature, high-pressure working fluid to reduce pressure and cool it through an expansion valve require a large amount of refrigerant to be extracted from the condenser for motor cooling. This refrigerant vaporizes after heat exchange in the motor cavity and is then drawn into and compressed by the compressor, increasing compressor power consumption. The air conditioning system disclosed herein avoids the increased compressor power consumption caused by compressing the cooling gas working fluid, improving thermal cycle efficiency by at least 6 percentage points. This improvement in thermal cycle efficiency becomes more pronounced as the heat pump temperature rises, resulting in a higher thermal cycle efficiency.

[0076] Moreover, this solution can cool the bearings, thus providing a technical path for the application of magnetic suspension and air suspension bearings in high-temperature heat pump systems.

[0077] like Figure 1 The scheme shown uses magnetic bearings. The table below compares the cycle efficiency (COP) of this scheme with existing schemes. Bearing and piping losses are ignored, compressor suction superheat and condenser subcooling are assumed to be zero, and water pump losses are not included in the COP calculation.

[0078] The cooling circuit fluid pumps (i.e., the first, second, and third pumps) in this disclosure consume a negligible amount of power. The existing solution's calculations were not iterated, accounting only for the increased compressor flow and compression power consumption associated with the motor coolant. Calculations show that, under a 40°C temperature rise, regardless of the refrigerant used, this solution improves the heat pump system's COP by over 6%. Under a 60°C temperature rise, this solution improves the COP by over 14%.

[0079] like Figure 2 In the solution shown, the two-stage compressor adopts a hydrostatic air bearing, and the inlet of the third pump is a subcooled liquid, which effectively avoids the damage of the hydrostatic air bearing caused by supplying gas to the hydrostatic air bearing.

[0080] like Figure 3 When the motor shown is in operation, the working fluid (i.e., refrigerant liquid) is pressurized by a first pump and enters the annular groove from the bottom of the housing 111. The working fluid rises evenly within the annular groove until it fills the entire groove. As the working fluid flows through the stator core area, it absorbs heat (including eddy current losses and hysteresis losses) generated by electromagnetic induction by contact with the core surface. When the working fluid rises to the top of the core, it forms a jet of a certain velocity through the through-holes in the side walls of the annular groove, directly impacting the enameled wire windings at the upper ends of the motor. The jet covers the winding surface, using forced convection to quickly remove heat from the copper wire. The enameled wire at the bottom of the motor is completely immersed in the liquid working fluid in the first and second storage spaces. Direct contact between the working fluid and the windings allows efficient heat conduction to remove heat from the copper.

[0081] When cooling the motor rotor, a saturated, low-temperature working fluid (gas and / or liquid) diffuses evenly within the geometric constraints of the housing, forming a continuous gas film around the outer edge of the rotor. The working fluid's initial temperature is lower than the rotor surface temperature, creating initial heat transfer potential. The low-temperature working fluid contacts the rapidly rotating rotor surface, absorbing electromagnetic and mechanical heat through forced convection. Electromagnetic heat is eddy current loss in the permanent magnets, conducted to the outer surface via the rotor jacket (non-magnetic material). Mechanical heat is viscous shear heat generated by friction between the rotor surface and the working fluid. After absorbing heat, the low-temperature working fluid's temperature increases and its density decreases. Buoyancy forces cause it to migrate toward the top of the rotor cavity, where it is accelerated away from the rotor surface by the centrifugal force of the rotor's rotation. Simultaneously, in the first and second chambers at the bottom of the housing, supercooled (or saturated) liquid working fluid exchanges heat with the windings, transforming into saturated (low-temperature) gas, which is continuously replenished. This creates a dynamic convection circulation around the rotor from bottom to top. Injection nozzles located at the top of the housing evenly spray the supercooled liquid working fluid downward. The falling, subcooled liquid working fluid mixes with the rising, high-temperature gas in the upper portion of the casing, exchanging sensible heat. The high-temperature gas releases heat to the liquid working fluid, lowering its temperature to saturation. The low-temperature liquid working fluid then absorbs heat and partially vaporizes, maintaining the system's working fluid phase equilibrium.

[0082] After the stator and rotor components are cooled, the mixed saturated working fluid is collected in the first and second accommodating spaces at the bottom of the housing and enters the external condenser through the drain port. The drain port can be in communication with the first and / or second accommodating spaces.

[0083] The temperature is lowered through condensation heat exchange, and the condensed working fluid is pressurized by the pump and then re-injected into the "supercooling working fluid inlet" to form a closed cycle.

[0084] Refer again Figure 3 The insulating air cavity is used to isolate direct heat transfer between the first and second volutes (volutes) and the bearing housing, blocking most of the radiant and conductive heat outside the air cavity. Residual heat is continuously absorbed by the internal water-cooling flow channel as it conducts through the metal of the bearing housing and is ultimately carried out of the system by the cooling water.

[0085] A sealed, insulated air chamber is created in the annular space between the volute (which contacts the high-temperature working fluid), the bearing seat, and the motor housing (the motor end face). This chamber is filled with an inert gas (or working fluid). Leveraging the gas's low thermal conductivity (only 1 / 100-1 / 1000 of that of metal), this chamber blocks the heat transfer path from the volute (i.e., high-temperature working fluid → volute metal wall → bearing seat → motor housing), effectively preventing the heat from reaching the motor cavity. A spiral or serpentine cooling channel is machined into the bearing seat (a key component connecting the volute to the rotor). Cooling water is injected through the "cold water inlet" and flows along the channel, closely following the inner wall of the bearing seat. The channel walls are in direct contact with the metal of the bearing seat, allowing the cooling water to continuously absorb heat transferred from the volute to the bearing seat through forced convection (conduction path: high-temperature working fluid → volute → bearing seat → cooling water). Furthermore, the channel is located near the bearing mounting location, allowing the cooling water to simultaneously absorb heat generated by friction between the bearing and rotor components during high-speed rotation (friction heat → bearing seat → cooling water).

[0086] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments / methods or examples. In addition, those skilled in the art may combine and combine different embodiments / methods or examples described in this specification and the features of different embodiments / methods or examples, unless they are contradictory.

[0087] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0088] Those skilled in the art will appreciate that the above embodiments are merely intended to clearly illustrate the present disclosure and are not intended to limit the scope of the present disclosure. Other changes or modifications may be made based on the above disclosure, and such changes or modifications are still within the scope of the present disclosure.

Claims

1. An air conditioning system, characterized in that: include: A two-stage compressor, the two-stage compressor comprising a first-stage compressor and a second-stage compressor; a first condenser connected to the second-stage compressor, the first condenser being configured to condense at least a portion of the high-temperature and high-pressure refrigerant gas discharged from the second-stage compressor into a refrigerant liquid; an evaporator, the evaporator being connected to the first condenser via an expansion valve and further connected to the first-stage compressor, the evaporator being configured to convert refrigerant liquid into refrigerant gas, and the refrigerant gas discharged from the evaporator being delivered to the first-stage compressor; A liquid storage tank, the liquid storage tank is used to store refrigerant liquid; a first pump connected to the liquid storage tank and the motor of the two-stage compressor and configured to supply refrigerant liquid in the liquid storage tank to the motor of the two-stage compressor; as well as The second condenser is connected to the motor of the two-stage compressor and the liquid storage tank. The second condenser is used to receive the refrigerant liquid and / or refrigerant gas discharged by the motor of the two-stage compressor, condense the refrigerant gas discharged by the motor into refrigerant liquid, and provide the refrigerant liquid to the liquid storage tank.

2. The air conditioning system according to claim 1, characterized in that The evaporator is connected to the inlet side of the first pump through a first pipeline, wherein a first switch valve is provided on the first pipeline.

3. The air conditioning system according to claim 1, characterized in that The liquid storage tank is further connected to the evaporator via a second pipeline, wherein a second pump and a second switch valve are provided on the second pipeline.

4. The air conditioning system according to claim 1, characterized in that Also includes: A supply tank is used to store refrigerant liquid, and the supply tank is connected to the liquid storage tank through a third pipeline, wherein a third switching valve and a third pump are provided on the third pipeline; wherein the supply tank is used to provide refrigerant liquid to the bearings of the motor of the two-stage compressor.

5. The air conditioning system according to claim 4, characterized in that The refrigerant liquid supplied to the bearings of the motor of the two-stage compressor flows through the bearings of the motor and is then discharged to the second condenser.

6. The air conditioning system according to claim 1, characterized in that The bearings of the motor of the two-stage compressor are arranged on a bearing seat, and the bearing seat is cooled by cold source water.

7. The air conditioning system according to claim 6, characterized in that An annular accommodating cavity is formed on the bearing seat, and the annular accommodating cavity is connected to a cold source water inlet and a cold source water outlet respectively. The cold source water inlet is used to provide cold source water into the annular accommodating cavity, and the cold source water outlet is used to discharge the cold source water in the annular accommodating cavity to the outside of the motor.

8. The air conditioning system according to claim 1, characterized in that The evaporator is also used to receive heat source water, and the temperature of the heat source water is reduced after flowing through the evaporator.

9. The air conditioning system according to claim 1, characterized in that The first condenser is further used to receive service water. The temperature of the service water is increased after the service water flows through the first condenser.

10. The air conditioning system according to claim 1, wherein: A liquid level gauge is provided in the liquid storage tank.

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