Air suspension centrifugal cold water unit

Abstract

The utility model discloses a kind of gas suspension centrifugal water chiller unit, its compressor is gas suspension centrifugal compressor;The coolant inlet of condenser is connected to the outlet of compressor;The coolant outlet of condenser is two-way: first road connects the liquid inlet of economizer, second road is sequentially connected the inlet of ball valve and second expansion valve;The motor heat dissipation pipeline inlet of compressor is connected to the outlet of second expansion valve;The inlet of isolating valve is connected to the motor heat dissipation pipeline outlet of compressor;The top of evaporator is connected to the outlet of isolating valve;The outlet of economizer is two-way: liquid outlet connects the inlet of first expansion valve;Gas outlet connects the medium-pressure cavity of compressor;The coolant inlet of evaporator is connected to the outlet of first expansion valve;The inlet of compressor is connected to the coolant outlet of evaporator.Using the utility model, not only can significantly improve system efficiency, but also can utilize the high-efficiency cooling motor of system itself cold source, without external cooling system.

Description

Technical Field

[0001] This utility model belongs to the field of refrigeration equipment technology, specifically relating to an air-suspended centrifugal chiller unit, which is particularly suitable for industrial and commercial cooling systems for efficient cooling of water or other media. Background Technology

[0002] In existing refrigeration systems, chillers are widely used in industrial and commercial sectors to cool various equipment and processes. Traditional chillers mainly rely on mechanical refrigeration cycles, achieving cooling through compressors, condensers, expansion valves, and evaporators. However, conventional centrifugal chiller units generally use oil-lubricated bearing systems, which have the following drawbacks: lubricating oil mixes into the refrigeration cycle, reducing heat exchange efficiency (evaporator / condenser heat transfer coefficient decreases by 15%–25%); a complex oil circuit system (oil pump, oil separator, oil return device) is required, increasing potential points of failure and maintenance costs; and mechanical bearing friction losses account for 3%–5% of the total energy consumption, hindering energy efficiency improvements.

[0003] Although air bearings can eliminate frictional losses and achieve oil-free operation, their technical characteristics introduce new challenges, such as motor heat dissipation problems. Oil-free lubrication means that the heat of the motor rotor cannot be dissipated through the oil circuit, and traditional air-cooling solutions are inefficient and noisy. Utility Model Content

[0004] The problem to be solved by this utility model is to provide an air-suspended centrifugal chiller unit that can not only significantly improve system efficiency, but also efficiently cool the motor using the system's own cold source, without the need for an external cooling system.

[0005] To address the aforementioned technical problems, this utility model provides an air-suspension centrifugal chiller unit, comprising a compressor, a condenser, an economizer, a first expansion valve, a second expansion valve, an evaporator, a ball valve, and an isolation valve; the compressor is an air-suspension centrifugal compressor; the compressor outlet is connected to the coolant inlet of the condenser; the condenser coolant outlet is divided into two paths: the first path connects to the liquid inlet of the economizer, and the second path connects sequentially to the inlets of the ball valve and the second expansion valve; the outlet of the second expansion valve is connected to the inlet of the compressor's motor cooling pipe; the outlet of the compressor's motor cooling pipe is connected to the inlet of the isolation valve; the outlet of the isolation valve is connected to the top of the evaporator; the economizer outlet is divided into two paths: the liquid outlet connects to the inlet of the first expansion valve; the gas outlet connects to the intermediate pressure chamber of the compressor; the outlet of the first expansion valve connects to the coolant inlet of the evaporator; and the coolant outlet of the evaporator connects to the inlet of the compressor.

[0006] As a preferred embodiment of this utility model, the economizer is equipped with a flash expansion valve, the inlet of which is connected to a pipeline flowing to the liquid inlet of the economizer, and the outlet of which is connected to the flash chamber of the economizer.

[0007] As a preferred embodiment of this utility model, a drying filter is provided on the pipelines flowing to the liquid inlet of the economizer and the inlet of the flash expansion valve; a filter is provided on the pipeline flowing to the inlet of the second expansion valve.

[0008] As a preferred embodiment of this utility model, the condenser is a shell-and-tube condenser, which consists of an outer shell and multiple rows of copper tubes. The copper tubes are disposed inside the outer shell, the flowing medium inside the copper tubes is externally supplied water, and the flowing medium outside the copper tubes is refrigerant. The coolant inlet of the condenser is disposed at the top of the outer shell, and the coolant outlet of the condenser is disposed at the bottom of the outer shell.

[0009] As a preferred embodiment of this utility model, the evaporator is a shell-and-tube evaporator, which consists of a shell and multiple rows of copper tubes. The copper tubes are disposed inside the shell, the flowing medium inside the copper tubes is water supplied from outside the unit, and the flowing medium outside the copper tubes is refrigerant from inside the unit. The copper tubes are submerged in liquid refrigerant inside the shell. The refrigerant inlet of the evaporator is located at the bottom of the shell, and the refrigerant outlet of the evaporator is located at the top of the shell.

[0010] As a preferred embodiment of this utility model, the top of the condenser is connected to the top of the evaporator through a hot gas bypass pipe, and an electric valve is provided on the hot gas bypass pipe.

[0011] As a preferred embodiment of this utility model, a check valve is provided on the pipeline from the outlet of the compressor to the condenser.

[0012] As a preferred embodiment of this utility model, the inlet of the condenser is provided with a first temperature sensor, the outlet of the condenser is provided with a second temperature sensor, and the coolant outlet of the condenser is provided with a third temperature sensor; the inner cavity of the condenser is provided with a first pressure sensor and a liquid level sensor.

[0013] As a preferred embodiment of this utility model, the inlet of the evaporator is provided with a fourth temperature sensor, the outlet of the evaporator is provided with a fifth temperature sensor, and the inner cavity of the evaporator is provided with a second pressure sensor.

[0014] As a preferred embodiment of this utility model, a third pressure sensor and a sixth temperature sensor are provided on the pipeline from the gas outlet of the economizer to the compressor; a fourth pressure sensor and a seventh temperature sensor are provided on the pipeline from the outlet of the evaporator to the compressor; a fifth pressure sensor and an eighth temperature sensor are provided on the pipeline from the outlet of the compressor to the condenser; and a sixth pressure sensor, a ninth temperature sensor, and a thermal switch are provided inside the motor cavity of the compressor.

[0015] Compared with the prior art, the air-suspension centrifugal chiller unit implementing this utility model has the following beneficial effects:

[0016] This embodiment of the utility model's air-suspension centrifugal chiller unit employs an air-suspension centrifugal compressor. Through air-suspension bearing technology, it eliminates the negative impact of lubricating oil on heat exchange efficiency, improving system efficiency and reducing maintenance. Secondly, by using an economizer (flash tank) to generate medium-pressure gas for intermediate replenishment, the compression ratio of the main refrigerant flow is reduced, lowering compressor power consumption. Simultaneously, the generated subcooled liquid reduces throttling losses, significantly improving system efficiency. Furthermore, through an independent motor cooling circuit, the high-pressure liquid refrigerant from the condenser is directly used. The resulting low-temperature refrigerant, after throttling through the second expansion valve, directly cools the motor. The refrigerant after cooling the motor is injected into the top of the evaporator to participate in the refrigeration cycle, eliminating waste. This method utilizes the system's own cold source to efficiently cool the motor, eliminating the need for an external cooling system. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings of the embodiments will be briefly described below.

[0018] Figure 1 This is a schematic diagram of the working principle of the air suspension centrifugal chiller unit according to an embodiment of this utility model.

[0019] Marked in the image:

[0020] Compressor 1; Compressor outlet 101; Compressor inlet 102; Motor cooling pipe inlet 103; Motor cooling pipe outlet 104; Gas inlet 105; Third pressure sensor 106; Sixth temperature sensor 107; Fourth pressure sensor 108; Seventh temperature sensor 109; Fifth pressure sensor 110; Eighth temperature sensor 111; Sixth pressure sensor 112; Ninth temperature sensor 113; Thermistor switch 114; Condenser 2; Condenser coolant inlet 21; Condenser coolant outlet 22; First temperature sensor 23; ... 24. Second temperature sensor; 25. Third temperature sensor; 26. First pressure sensor; 27. Liquid level sensor; 3. Economizer; 31. Liquid inlet; 32. Liquid outlet; 33. Gas outlet; 4. First expansion valve; 5. Second expansion valve; 6. Evaporator; 61. Coolant inlet of evaporator; 62. Coolant outlet of evaporator; 63. Fourth temperature sensor; 64. Fifth temperature sensor; 65. Second pressure sensor; 7. Ball valve; 8. Isolation valve; 9. Hot gas bypass pipe; 10. Flash expansion valve; 11. Dryer filter; 12. Filter; 13. Electric valve; 14. Bypass valve; 15. Check valve. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] like Figure 1 As shown, this is a preferred embodiment of the present invention.

[0024] An air-suspension centrifugal chiller unit includes a compressor 1, a condenser 2, an economizer 3, a first expansion valve 4, a second expansion valve 5, an evaporator 6, a ball valve 7, and an isolation valve 8. The compressor 1 is an air-suspension centrifugal compressor. The outlet 101 of the compressor 1 is connected to the coolant inlet 21 of the condenser 2. The coolant outlet 22 of the condenser 2 is divided into two paths: the first path connects to the liquid inlet 31 of the economizer 3, and the second path connects sequentially to the inlets of the ball valve 7 and the second expansion valve 5. The outlet of the second expansion valve 5 is connected to the motor cooling pipe inlet 103 of the compressor 1. The motor cooling pipe outlet 104 of the compressor 1 is connected to the inlet of the isolation valve 8. The outlet of the isolation valve 8 is connected to the top of the evaporator 6. The outlet of the economizer 3 is divided into two paths: a liquid outlet 32 ​​connects to the inlet of the first expansion valve 4, and a gas outlet 33 connects to the intermediate pressure chamber of the compressor 1. The outlet of the first expansion valve 4 connects to the coolant inlet 61 of the evaporator 6. The coolant outlet 62 of the evaporator 6 connects to the inlet 102 of the compressor 1.

[0025] Understandably, compressor 1 is the core power component, employing air-bearing technology (requiring no lubrication) to compress low-temperature, low-pressure gaseous refrigerant into high-temperature, high-pressure gaseous refrigerant. Condenser 2 is the heat-releasing component (capable of supplying external water for heating), cooling and condensing the high-temperature, high-pressure gaseous refrigerant discharged from compressor 1 into medium-temperature, high-pressure liquid refrigerant. Economizer 3 is a key energy-saving component; it's a flash evaporator where the high-pressure liquid refrigerant from condenser 2 enters and is depressurized for flash evaporation, producing a portion of medium-pressure saturated gaseous refrigerant and a lower-temperature saturated (or subcooled) liquid refrigerant. First expansion valve 4 is the main throttling device, reducing the pressure of the subcooled liquid refrigerant from economizer 3 into a low-temperature, low-pressure gas-liquid two-phase mixture. Second expansion valve 5 is an auxiliary throttling device used to regulate the refrigerant flow rate into the motor cooling circuit. Evaporator 6 is the heat-absorbing component (capable of supplying external water for cooling), where the low-temperature, low-pressure gas-liquid two-phase refrigerant from first expansion valve 4 evaporates, becoming a low-temperature, low-pressure gaseous refrigerant. Ball valve 7 is installed on the pipeline from condenser coolant outlet 22 to the inlet of second expansion valve 5, serving as an on / off switch for this branch. Isolation valve 8 is installed on the pipeline from compressor 1 motor cooling pipe outlet 104 to the top of evaporator 6, used to isolate this branch (e.g., during maintenance).

[0026] The workflow is as follows:

[0027] Compression: The low-temperature, low-pressure gaseous refrigerant from the evaporator 6 is mixed with the medium-pressure gaseous refrigerant from the economizer gas outlet 33 (usually mixed in the medium-pressure chamber of the compressor 1, and the medium-pressure gaseous refrigerant from the economizer gas outlet 33 enters through the gas inlet 105), and is compressed into a high-temperature, high-pressure gas by the air-suspension centrifugal compressor and discharged to the condenser 2.

[0028] Condensation: The high-temperature and high-pressure gas is cooled by externally supplied water in condenser 2 and condensed into a medium-temperature and high-pressure liquid.

[0029] Condensate diversion:

[0030] Main path (to economizer 3): Most of the high-pressure liquid enters the liquid inlet 31 of economizer 3 (flash tank);

[0031] Branch circuit (motor cooling): A small portion of high-pressure liquid flows to the second expansion valve 5 through ball valve 7 (open state).

[0032] Flash evaporation in economizer 3: The high-pressure liquid entering economizer 3 experiences a pressure drop, resulting in flash evaporation. The medium-pressure saturated gas generated by flash evaporation is drawn out from the gas outlet 33 at the top of economizer 3 and returned directly to the inlet 102 or intermediate gas inlet 105 of compressor 1, where it is compressed to the discharge pressure. This portion of gas reduces the flow rate of the main compression stream, thus reducing compression power consumption (power-saving principle). Meanwhile, the subcooled saturated liquid generated by flash evaporation accumulates at the bottom of economizer 3 and is drawn out from the liquid outlet 32.

[0033] Main refrigerant throttling and evaporation: The subcooled liquid from the economizer 3 enters the first expansion valve 4, which throttles and depressurizes it into a low-temperature, low-pressure gas-liquid two-phase mixture. This mixture enters the refrigerant inlet 61 of the evaporator 6. In the evaporator 6, the liquid refrigerant absorbs heat from the externally supplied water and evaporates, completely becoming a low-temperature, low-pressure gas, which flows out from the refrigerant outlet 62 of the evaporator 6 and returns to the compressor inlet 102.

[0034] Motor cooling circuit: The high-pressure liquid diverted from condenser 2 flows through the second expansion valve 5, which throttles and reduces its pressure into a low-temperature, low-pressure gas-liquid two-phase mixture or a low-temperature liquid. This low-temperature refrigerant enters the motor cooling pipe inlet 103 of compressor 1. The low-temperature refrigerant flows through the cooling channels around the motor, absorbing the heat generated by the motor's operation, and either evaporates or its temperature rises. The refrigerant that has absorbed the heat from the motor flows out from the motor cooling pipe outlet 104 of compressor 1. The outflowing refrigerant is injected into the top of evaporator 6 through isolation valve 8 (open state). Due to the low pressure at the top of evaporator 6, this portion of refrigerant will quickly flash or continue to evaporate, participating in the heat absorption process of evaporator 6, and eventually also becomes gas and returns to compressor 1.

[0035] Therefore, the air-suspension centrifugal chiller unit according to this utility model embodiment adopts an air-suspension centrifugal compressor, and eliminates the negative impact of lubricating oil on heat exchange efficiency through air-suspension bearing technology, thereby improving system efficiency and reducing maintenance. Secondly, the intermediate-pressure gas generated by flash evaporation in the economizer 3 (flash tank) is used for intermediate gas replenishment, reducing the compression ratio of the main refrigerant flow and lowering compressor power consumption; at the same time, the generated subcooled liquid reduces throttling losses, significantly improving system efficiency. Furthermore, through an independent motor cooling circuit, the high-pressure liquid refrigerant from the condenser 2 is directly used to cool the motor with the low-temperature refrigerant generated after throttling through the second expansion valve 5; the refrigerant after cooling the motor is injected into the top of the evaporator 6 to participate in the refrigeration cycle, without waste; this method utilizes the system's own cold source to efficiently cool the motor, eliminating the need for an external cooling system.

[0036] For example, both the first expansion valve 4 and the second expansion valve 5 are preferably electronic expansion valves to precisely control the flow rate of the main circuit and the liquid circuit of the economizer 3, as well as the flow rate and temperature of the motor cooling circuit.

[0037] For example, the economizer 3 is equipped with a flash expansion valve 10. The inlet of the flash expansion valve 10 is connected to the pipeline flowing to the liquid inlet 31 of the economizer 3, and the outlet of the flash expansion valve 10 is connected to the flash chamber of the economizer 3. Thus, before entering the economizer 3, part of the high-pressure liquid refrigerant is throttled and depressurized by the flash expansion valve 10 into a gas-liquid two-phase state, and then enters the flash chamber for separation.

[0038] For example, in order to ensure the long-term stable operation of the system and avoid failure of key valves, a dryer filter 11 is provided on the pipelines flowing to the liquid inlet 31 of the economizer 3 and the inlet of the flash expansion valve 10 to adsorb moisture and impurities in the refrigerant in the main circuit of the economizer 3 and prevent ice blockage and dirt blockage; a filter 12 is provided on the pipeline flowing to the inlet of the second expansion valve 5 to protect the second expansion valve 5 of the motor cooling branch from particulate matter blockage.

[0039] For example, the condenser 2 is a shell-and-tube condenser, consisting of an outer shell and multiple rows of copper tubes. The copper tubes are disposed inside the outer shell, and the flowing medium inside the copper tubes is externally supplied water, while the flowing medium outside the copper tubes is refrigerant. The refrigerant inlet 21 of the condenser 2 is located at the top of the outer shell, and the refrigerant outlet 22 of the condenser 2 is located at the bottom of the outer shell. Thus, the high-temperature refrigerant gas discharged from the compressor 1 enters the shell side from the top, exchanges heat with the cooling water inside the copper tubes in a counter-current flow, gradually condenses into liquid, and is discharged from the bottom. The top air inlet and bottom liquid outlet design enhances condensation efficiency, utilizes gravity to promote liquid film flow, and reduces heat exchange resistance.

[0040] For example, the evaporator 6 is a shell-and-tube evaporator, consisting of a shell and multiple rows of copper tubes. The copper tubes are disposed inside the shell, the flowing medium inside the copper tubes is water supplied from outside the unit, and the flowing medium outside the copper tubes is refrigerant from inside the unit. The copper tubes are submerged in liquid refrigerant inside the shell. The refrigerant inlet 61 of the evaporator 6 is located at the bottom of the shell, and the refrigerant outlet 62 of the evaporator 6 is located at the top of the shell. Thus, the low-temperature refrigerant, after being throttled by the first expansion valve 4, enters from the bottom, submerges the copper tube bundle, and absorbs heat from the chilled water inside the tubes. The evaporated gas returns to the compressor 1 from the top. The flooded design and bottom liquid inlet ensure complete immersion of the copper tubes, improving evaporation heat exchange efficiency; at the same time, top venting avoids the risk of liquid slugging.

[0041] For example, the top of the condenser 2 is connected to the top of the evaporator 6 via a hot gas bypass pipe 9, and an electric valve 13 is provided on the hot gas bypass pipe 9. Under low load, the electric valve 13 opens, directly bypassing the exhaust gas from the compressor 1 to the top of the evaporator 6 to maintain stable evaporation pressure.

[0042] For example, a check valve 15 is provided on the pipeline from the outlet of the compressor 1 to the condenser 2 to prevent the high-pressure refrigerant in the condenser 2 from flowing back and impacting the compressor impeller when the compressor stops.

[0043] For example, the condenser 2 has a first temperature sensor 23 at its inlet, a second temperature sensor 24 at its outlet, and a third temperature sensor 25 at its coolant outlet 22. The condenser 2's inner cavity is equipped with a first pressure sensor 26 and a liquid level sensor 27. The first and second temperature sensors 23 and 24 monitor the temperatures T1 and T2 of the externally supplied water entering and exiting the condenser 2, calculate the external supply water temperature difference, and combine this with the flow rate to obtain the condensing heat load. The first pressure sensor 26 monitors the condensing pressure and calculates the saturation temperature. The third temperature sensor 25 monitors the temperature of the medium-temperature, high-pressure liquid refrigerant exiting the condenser 2; combined with the condensing pressure, it facilitates the calculation of subcooling, thereby optimizing the economizer's liquid inlet state. If the subcooling is insufficient, the external supply water flow rate in the condenser 2 is increased. The liquid level sensor 27 detects the refrigerant level to prevent overflow or drying out. Thus, through multi-parameter monitoring of the condenser, the cooling water flow rate can be optimized in real time to maintain the optimal condensing temperature; liquid level interlock control prevents a decrease in heat exchange efficiency.

[0044] For example, the evaporator 6 has a fourth temperature sensor 63 at its inlet, a fifth temperature sensor 64 at its outlet, and a second pressure sensor 65 inside its cavity. The fourth and fifth temperature sensors 63 and 64 monitor the temperatures T3 and T4 of the externally supplied water entering and exiting the evaporator 6, calculate the temperature difference of the externally supplied water, and combine this with the flow rate to obtain the cooling capacity output. The second pressure sensor 65 monitors the evaporation pressure and controls the compressor's suction state. Thus, through multi-parameter monitoring of the evaporator, the user's cooling load can be accurately matched, avoiding overcooling / undercooling; pressure protection prevents evaporation temperatures from becoming too low and causing freezing.

[0045] For example, a third pressure sensor 106 and a sixth temperature sensor 107 are provided on the pipeline from the gas outlet 33 of the economizer 3 to the compressor 1. The third pressure sensor 106 is used to monitor the pressure of the gas supplied to the compressor 1, and the sixth temperature sensor 107 is used to monitor the temperature of the gas supplied to the compressor 1, so as to calculate the superheat of the gas supplied and dynamically adjust the opening of the flash expansion valve 10 to ensure that the gas supplied is saturated gas and avoid liquid droplets impacting the compressor impeller.

[0046] For example, a fourth pressure sensor 108 and a seventh temperature sensor 109 are provided on the pipeline flowing from the outlet of the evaporator 6 to the compressor 1. The fourth pressure sensor 108 is used to monitor the suction pressure of the compressor 1, and the seventh temperature sensor 109 is used to monitor the suction temperature of the compressor 1, so as to calculate the suction superheat, prevent droplets from impacting the compressor impeller, and control the opening of the first expansion valve 4 to ensure that the suction reaches a suitable superheat (e.g., >5°C).

[0047] For example, a fifth pressure sensor 110 and an eighth temperature sensor 111 are provided on the pipeline from the outlet 101 of the compressor 1 to the condenser 2; wherein, the fifth pressure sensor 110 is used to monitor the discharge pressure of the compressor 1, and the eighth temperature sensor 111 is used to monitor the discharge temperature of the compressor 1, so as to calculate the compression ratio in combination with the suction pressure. When the compression ratio changes abruptly (i.e. when a surge warning occurs), the bypass valve 14 is activated, and part of the gas on the suction side of the compressor 1 is diverted to the condenser 2.

[0048] For example, the compressor 1 has a sixth pressure sensor 112, a ninth temperature sensor 113, and a thermal switch 114 installed in its motor cavity. The sixth pressure sensor 112 monitors the pressure in the motor cooling circuit, the ninth temperature sensor 113 monitors the temperature of the motor windings, and the thermal switch 114 provides redundant protection (power is hard-cut off when the temperature exceeds a threshold). Thus, through multi-parameter monitoring of the motor cavity, triple motor protection is achieved, such as adjusting the second expansion valve 5 when the pressure is abnormal, reducing the frequency when the temperature exceeds the limit, and using the thermal switch for emergency shutdown.

[0049] Understandably, all sensor data is input into the unit controller, forming a fully closed-loop intelligent control system.

[0050] In the description of this utility model, it should be understood that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" used in this utility model should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0051] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent changes made in accordance with the claims of the present utility model shall still fall within the scope of the present utility model.

Claims

1. An air-suspension centrifugal chiller unit, characterized in that, It includes a compressor, condenser, economizer, first expansion valve, second expansion valve, evaporator, ball valve, and isolation valve; the compressor is an air-suspension centrifugal compressor. The compressor outlet is connected to the coolant inlet of the condenser; The coolant outlet of the condenser is divided into two paths: The first path connects to the liquid inlet of the economizer; The second path connects sequentially to the inlet of the ball valve and the inlet of the second expansion valve; The outlet of the second expansion valve is connected to the inlet of the compressor's motor cooling pipe; The outlet of the compressor's motor cooling pipe is connected to the inlet of the isolation valve; The outlet of the isolation valve is connected to the top of the evaporator; The exit of the economizer is divided into two routes: The liquid outlet is connected to the inlet of the first expansion valve; The gas outlet is connected to the intermediate pressure chamber of the compressor; The outlet of the first expansion valve is connected to the coolant inlet of the evaporator; The coolant outlet of the evaporator is connected to the inlet of the compressor.

2. The air-suspended centrifugal chiller unit as described in claim 1, characterized in that, The economizer is equipped with a flash expansion valve, the inlet of which is connected to a pipeline flowing to the liquid inlet of the economizer, and the outlet of which is connected to the flash chamber of the economizer.

3. The air-suspended centrifugal chiller unit as described in claim 2, characterized in that, A dryer filter is installed on the pipeline leading to the liquid inlet of the economizer and the inlet of the flash expansion valve; a filter is installed on the pipeline leading to the inlet of the second expansion valve.

4. The air-suspended centrifugal chiller unit as described in claim 1, characterized in that, The condenser is a shell-and-tube condenser, which consists of an outer shell and multiple rows of copper tubes. The copper tubes are located inside the outer shell, and the flowing medium inside the copper tubes is externally supplied water, while the flowing medium outside the copper tubes is refrigerant. The coolant inlet of the condenser is located at the top of the outer casing, and the coolant outlet of the condenser is located at the bottom of the outer casing.

5. The air-suspended centrifugal chiller unit as described in claim 1, characterized in that, The evaporator is a shell-and-tube evaporator, which consists of an outer shell and multiple rows of copper tubes. The copper tubes are located inside the outer shell. The flowing medium inside the copper tubes is water supplied from outside the unit, and the flowing medium outside the copper tubes is refrigerant from inside the unit. The copper tubes are submerged in liquid refrigerant inside the outer shell. The coolant inlet of the evaporator is located at the bottom of the outer casing, and the coolant outlet of the evaporator is located at the top of the outer casing.

6. The air-suspended centrifugal chiller unit as described in claim 1, characterized in that, The top of the condenser is connected to the top of the evaporator via a hot gas bypass pipe, and an electric valve is installed on the hot gas bypass pipe.

7. The air-suspended centrifugal chiller unit as described in claim 1, characterized in that, A check valve is provided on the pipeline from the outlet of the compressor to the condenser.

8. The air-suspended centrifugal chiller unit as described in any one of claims 1 to 7, characterized in that, The condenser is equipped with a first temperature sensor at the water inlet, a second temperature sensor at the water outlet, and a third temperature sensor at the coolant outlet; the condenser is also equipped with a first pressure sensor and a liquid level sensor inside the cavity.

9. The air-suspended centrifugal chiller unit as described in any one of claims 1 to 7, characterized in that, The evaporator is equipped with a fourth temperature sensor at its inlet, a fifth temperature sensor at its outlet, and a second pressure sensor inside its cavity.

10. The air-suspended centrifugal chiller unit as described in any one of claims 1 to 7, characterized in that, A third pressure sensor and a sixth temperature sensor are installed on the pipeline from the gas outlet of the economizer to the compressor; a fourth pressure sensor and a seventh temperature sensor are installed on the pipeline from the outlet of the evaporator to the compressor; a fifth pressure sensor and an eighth temperature sensor are installed on the pipeline from the outlet of the compressor to the condenser; a sixth pressure sensor, a ninth temperature sensor, and a thermal switch are installed inside the motor cavity of the compressor.

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