Variable-working-condition magnetic suspension multi-stage compression cooling circulation system

Abstract

The utility model belongs to the technical field of magnetic suspension refrigeration and heating systems, and discloses a variable working condition magnetic suspension multistage compression cooling circulation system which comprises an evaporator and a condenser, and a multistage pressurization pipeline and a throttling pipeline are arranged between the evaporator and the condenser. The inlet end of the multi-stage pressurizing pipeline is communicated with the outlet end of a heat exchange coil pipe in the evaporator, the outlet end of the multi-stage pressurizing pipeline is communicated with the inlet end of a heat exchange coil pipe in the condenser, the inlet end of the throttling pipeline is communicated with the outlet end of the heat exchange coil pipe in the condenser, and the other end of the throttling pipeline is communicated with the inlet end of the heat exchange coil pipe in the evaporator; the heat exchange coil of the condenser is further connected with a cooling pipeline in series, and the other end of the cooling pipeline is sequentially communicated with a cooling flow channel of the magnetic suspension compressor on the multi-stage pressurizing pipeline. The air conditioner can meet the requirements for high-temperature refrigeration in summer and low-temperature heating in winter, and continuous and efficient operation under variable working conditions is achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of magnetic levitation refrigeration and heat systems, and specifically relates to a variable-condition magnetic levitation multi-stage compression cooling cycle system. Background Technique

[0002] At present, the existing magnetic levitation centrifugal refrigeration compressors are mainly applied to water-cooled chillers. This type of chiller is based on the magnetic levitation oil-free technology and jointly constitutes a magnetic levitation centrifugal chiller in combination with throttling devices such as falling-film or flooded heat exchangers and electronic expansion valves. Compared with conventional centrifugal units, magnetic levitation variable-frequency centrifugal chillers have great advantages, mainly including: high energy efficiency at part load; no complex oil circuit system, few moving parts, low daily maintenance costs, no friction loss, and low operating noise and vibration.

[0003] Compared with ordinary variable-frequency centrifuges, the key of the magnetic levitation variable-frequency centrifuge lies in the magnetic levitation centrifugal compressor. The magnetic levitation system consists of a rotor, sensors, a controller, and an actuator. The actuator includes two parts: an electromagnet and a power amplifier. The magnetic levitation bearing is a kind of bearing that uses a magnetic field to suspend the rotor, so that there is no mechanical contact and friction during rotation, and no mechanical bearing and bearing lubrication system are required.

[0004] Compared with magnetic levitation centrifugal chillers, heat pump units require a larger operating range for the compressor, higher rotational speed and motor power of the compressor. Therefore, it is necessary to develop a unit with a wider operating range and efficient operation throughout the year, so as to meet the needs of high-temperature refrigeration in summer and low-temperature heating in winter, as well as the part-load requirements in spring and autumn. Content of the Utility Model

[0005] The main technical problem to be solved by the utility model is to provide a variable-condition magnetic levitation multi-stage compression cooling cycle system, which can meet the needs of high-temperature refrigeration in summer and low-temperature heating in winter, and achieve continuous and efficient operation under variable conditions; the operating boundary range and refrigeration and heating reliability of the unit are higher, with ultra-low energy efficiency operation under variable load and no maintenance cost; and the overall structure is simple and easy to use.

[0006] To solve the above technical problems, the utility model provides the following technical solutions:

[0007] A variable-condition magnetic levitation multi-stage compression cooling cycle system, comprising an evaporator and a condenser. A multi-stage pressurization pipeline and a throttling pipeline are arranged between the evaporator and the condenser. The inlet end of the multi-stage pressurization pipeline is communicated with the outlet end of the heat exchange coil in the evaporator, and the outlet end of the multi-stage pressurization pipeline is communicated with the inlet end of the heat exchange coil in the condenser. The inlet end of the throttling pipeline is communicated with the outlet end of the heat exchange coil in the condenser, and the other end of the throttling pipeline is communicated with the inlet end of the heat exchange coil in the evaporator; A cooling pipeline is also connected in series on the heat exchange coil of the condenser, and the other end of the cooling pipeline is sequentially communicated with the cooling flow channels of the magnetic levitation compressors on the multi-stage pressurization pipeline.

[0008] The following is the further optimization of the above technical solution by the present utility model:

[0009] The multi-stage pressurization pipeline includes a medium pressurization pipe. A first-stage compressor and a second-stage compressor are sequentially connected in series on the medium pressurization pipe. A branch pressurization pipe is also connected in parallel on the medium pressurization pipe. The inlet end of the branch pressurization pipe is communicated with the medium pressurization pipe at the inlet and outlet ends of the second-stage compressor, and the outlet end of the branch pressurization pipe is communicated with the medium pressurization pipe at the outlet end of the second-stage compressor. After the branch pressurization pipe is connected, the medium in the medium pressurization pipe no longer enters the second-stage compressor.

[0010] Further optimization: A first valve, a first pressure sensor and a first temperature sensor are sequentially arranged on the medium pressurization pipe between the evaporator and the first-stage compressor along the flow direction of the medium; A first electric valve, a second pressure sensor and a second temperature sensor are connected in series on the front side of the inlet end of the second-stage compressor on the medium pressurization pipe; The first electric valve, the second pressure sensor and the second temperature sensor are sequentially arranged along the flow direction of the medium.

[0011] Further optimization: A second electric valve, a third pressure sensor and a third temperature sensor are sequentially arranged on the branch pressurization pipe along the flow direction of the medium. The second electric valve is used to control the on-off of the branch pressurization pipe.

[0012] Further optimization: A check valve and a second valve are connected in series on the medium pressurization pipe near the condenser, and the check valve and the second valve are sequentially arranged along the flow direction of the medium.

[0013] Further optimization: The throttling pipeline includes a throttling main pipe. A third valve, a filter barrel, a throttling device and a fourth valve are sequentially connected in series on the throttling main pipe along the flow direction of the medium.

[0014] Further optimization: The cooling pipeline includes a cooler. The inlet end of the cooler is communicated with a cooling main pipe, and the inlet end of the cooling main pipe is communicated with the heat exchange coil in the condenser; A first cooling valve, a first filter and a second cooling valve are sequentially arranged on the cooling main pipe along the flow direction of the medium;

[0015] A first cooling branch pipe is connected to the outlet end of the cooler, and the other end of the first cooling branch pipe is connected to the cooling flow channel on the secondary compressor through a plurality of first branch pipes; a first regulating valve is connected in series on each first branch pipe.

[0016] A second cooling branch pipe is connected in series on the first cooling branch pipe, and the other end of the second cooling branch pipe is connected to the cooling flow channel on the primary compressor through a plurality of second branch pipes; a second regulating valve is connected in series on each second branch pipe.

[0017] Further optimization: A cooling branch is connected in series on the cooling main pipe between the first filter and the second cooling valve, and the other end of the cooling branch is connected to the first cooling branch pipe; a third cooling valve is connected in series on the cooling branch, and the third cooling valve is used to control the on-off of the cooling branch.

[0018] Further optimization: A flash tank is also arranged on one side of the medium booster pipe, the gas outlet end of the flash tank is connected to a flash branch pipe, the other end of the flash branch pipe is connected to the medium booster pipe at the inlet end of the secondary compressor, and a fifth cooling valve is connected in series on the flash branch pipe.

[0019] Further optimization: The outlet ends of the cooling flow channels of the primary compressor and the secondary compressor are connected to a confluence main pipe, and the other end of the confluence main pipe is connected to the inlet end of the flash tank; a fourth cooling valve is connected in series on the confluence main pipe near the outlet end of the cooling flow channel of the secondary compressor.

[0020] The outlet end of the flash tank is connected to a reflux main pipe, and the other end of the reflux main pipe is connected to the heat exchange coil in the evaporator; a sixth cooling valve is connected in series on the reflux main pipe.

[0021] The utility model adopts the above technical solutions and has the following beneficial effects:

[0022] 1. The variable-condition magnetic levitation multi-stage compression cooling cycle system adopts two-stage compressors to work together. In winter, high-temperature hot water can be produced for heating scenarios. At the same time, the unit can meet the operation requirements of a conventional chiller and take into account the operation in spring and autumn. The variable-condition magnetic levitation multi-stage compression cooling cycle system has a wider operation range and can operate efficiently throughout the year.

[0023] 2. The structure of the variable-condition magnetic levitation multi-stage compression cooling cycle system is relatively simpler than that of an oil-containing system, and there is no need to consider oil return, oil temperature, and pipeline system configuration; the unit has fewer accessories, higher system compatibility and controllability, and higher part-load power saving rate.

[0024] 3. The variable-condition magnetic levitation multi-stage compression cooling cycle system can meet the requirement of discharging water at a conventional 7°C, and at the same time can produce high-temperature hot water above 65°C, realizing multiple functions with one machine, and is especially suitable for places where enterprises have heating and cooling requirements.

[0025] 4. When heating is required in winter, the condenser uses side outputs hot water for users to use; the heating cycle is completed reciprocally in turn; and in this process, the first-stage compressor and the second-stage compressor can increase the pressure ratio of the single-stage compressor by more than 1 time through design matching, significantly improve the suction and discharge pressures and the operating range of the unit, and the system can adapt to the variable operating range of the low-temperature heat pump unit.

[0026] 5. When operating in the winter heating condition, the temperature of the magnetic levitation motor of the second-stage compressor is relatively high, and at the same time the temperature of the hot water on the use side is relatively high, and the temperature of the refrigerant flowing out from the outlet end of the condenser is relatively high, and cooling needs to be achieved through the cooling pipeline; at the same time, in order to reduce the superheat at the outlet of the second-stage compressor and increase the refrigerant flow rate, a flash structure is added to the cooling system to adjust the air supply to the suction port of the second-stage compressor.

[0027] The following further describes the present invention in conjunction with the drawings and embodiments. Description of the Drawings

[0028] Figure 1 It is a schematic diagram of the overall structure of the embodiment of the present invention;

[0029] Figure 2 It is a schematic diagram of the structure when operating in the summer refrigeration condition in the embodiment of the present invention.

[0030] In the figure: 1 - evaporator; 101 - cold source inlet pipe; 102 - cold source outlet pipe; 2 - condenser; 201 - heat source inlet pipe; 202 - heat source outlet pipe; 3 - multi-stage pressurization pipeline; 301 - medium pressurization pipe; 302 - first-stage compressor; 303 - second-stage compressor; 304 - branch pressurization pipe; 305 - first valve; 306 - first electric valve; 307 - first pressure sensor; 308 - first temperature sensor; 309 - second pressure sensor; 310 - second temperature sensor; 311 - second electric valve; 312 - third pressure sensor; 313 - third temperature sensor; 314 - check valve; 315 - second valve; 4 - cooling pipeline; 401 - cooling main pipe; 402 - cooler; 403 - first cooling valve; 404 - first filter; 405 - second cooling valve; 406 - cooling branch; 407 - third cooling valve; 408 - first sight glass; 409 - first regulating valve; 410 - first cooling branch pipe; 411 - second cooling branch pipe; 412 - second sight glass; 413 - second regulating valve; 414 - cooling water inlet pipe; 415 - cooling water outlet pipe; 5 - flash tank; 501 - flash branch pipe; 502 - fifth cooling valve; 503 - confluence main pipe; 504 - return main pipe; 505 - fourth cooling valve; 506 - sixth cooling valve; 6 - throttling pipeline; 601 - throttling main pipe; 602 - third valve; 603 - filter barrel; 604 - throttling device; 605 - fourth valve. Detailed implementation mode

[0031] As shown Figure 1-2 : A variable-condition magnetic levitation multi-stage compression cooling cycle system includes an evaporator 1 and a condenser 2. A multi-stage pressurization pipeline 3 and a throttling pipeline 6 are arranged between the evaporator 1 and the condenser 2. The inlet end of the multi-stage pressurization pipeline 3 is communicated with the outlet end of the heat exchange coil in the evaporator 1, and the outlet end of the multi-stage pressurization pipeline 3 is communicated with the inlet end of the heat exchange coil in the condenser 2. The inlet end of the throttling pipeline 6 is communicated with the outlet end of the heat exchange coil in the condenser 2, and the other end of the throttling pipeline 6 is communicated with the inlet end of the heat exchange coil in the evaporator 1; A cooling pipeline 4 is also connected in series on the heat exchange coil of the condenser 2, and the other end of the cooling pipeline 4 is sequentially communicated with the cooling flow channel of the magnetic levitation compressor on the multi-stage pressurization pipeline 3.

[0032] A cold source water inlet pipe 101 and a cold source water outlet pipe 102 are arranged on the usage side of the evaporator 1, and the cold source water inlet pipe 101 and the cold source water outlet pipe 102 are respectively communicated with the inner cavity of the evaporator 1.

[0033] When refrigeration is required, external cold source water enters the evaporator 1 through the cold source water inlet pipe 101. At this time, the cold source water exchanges heat with the heat exchange coil in the evaporator 1 to realize refrigeration of the cold source water, and then cold water is output through the cold source water outlet pipe 102 to realize the refrigeration operation.

[0034] A heat source water inlet pipe 201 and a heat source water outlet pipe 202 are arranged on the usage side of the condenser 2, and the heat source water inlet pipe 201 and the heat source water outlet pipe 202 are respectively communicated with the inner cavity of the condenser 2.

[0035] When heating is required, external heat source water enters the condenser 2 through the heat source water inlet pipe 201. At this time, the heat source water exchanges heat with the heat exchange coil in the condenser 2 to realize heating of the heat source water, and then hot water is output through the heat source water outlet pipe 202 to realize the heating operation.

[0036] The multi-stage pressurization pipeline 3 includes a medium pressurization pipe 301. The inlet end of the medium pressurization pipe 301 is communicated with the outlet end of the heat exchange coil in the evaporator 1, and the outlet end of the medium pressurization pipe 301 is communicated with the inlet end of the heat exchange coil in the condenser 2.

[0037] An first-stage compressor 302 and a second-stage compressor 303 are sequentially connected in series on the medium pressurization pipe 301. A branch pressurization pipe 304 is also connected in parallel on the medium pressurization pipe 301. The inlet end of the branch pressurization pipe 304 is communicated with the medium pressurization pipe 301 at the inlet and outlet ends of the second-stage compressor 303, and the outlet end of the branch pressurization pipe 304 is communicated with the medium pressurization pipe 301 at the outlet end of the second-stage compressor 303. After the branch pressurization pipe 304 is connected, the medium in the medium pressurization pipe 301 no longer enters the second-stage compressor 303.

[0038] A first valve 305 is connected in series at a position on the medium pressurizing pipe 301 close to the evaporator 1, and the first valve 305 is used to open or close the inlet end of the medium pressurizing pipe 301.

[0039] A first pressure sensor 307 and a first temperature sensor 308 are connected in series on the medium pressurizing pipe 301 on the front side of the inlet and outlet ends of the first-stage compressor 302, and the first pressure sensor 307 and the first temperature sensor 308 are arranged in sequence along the flow direction of the medium.

[0040] A first electric valve 306, a second pressure sensor 309 and a second temperature sensor 310 are connected in series on the medium pressurizing pipe 301 on the front side of the inlet end of the second-stage compressor 303; the first electric valve 306, the second pressure sensor 309 and the second temperature sensor 310 are arranged in sequence along the flow direction of the medium.

[0041] The first electric valve 306 is used to control the on-off of the inlet end of the second-stage compressor 303, and thus control whether the medium in the medium pressurizing pipe 301 flows into the second-stage compressor 303.

[0042] The second pressure sensor 309 is used to detect the flow pressure of the medium in the medium pressurizing pipe 301 at the inlet end of the second-stage compressor 303;

[0043] The second temperature sensor 310 is used to detect the temperature of the medium in the medium pressurizing pipe 301 at the inlet end of the second-stage compressor 303.

[0044] A second electric valve 311, a third pressure sensor 312 and a third temperature sensor 313 are arranged in sequence along the flow direction of the medium on the branch pressurizing pipe 304, and the second electric valve 311 is used to control the on-off of the branch pressurizing pipe 304.

[0045] The third pressure sensor 312 is used to detect the flow pressure of the medium in the branch pressurizing pipe 304; the third temperature sensor 313 is used to detect the temperature of the medium in the branch pressurizing pipe 304.

[0046] A check valve 314 and a second valve 315 are connected in series at a position on the medium pressurizing pipe 301 close to the condenser 2, and the check valve 314 and the second valve 315 are arranged in sequence along the flow direction of the medium.

[0047] The check valve 314 is used to conduct one-way diversion of the flow direction of the medium in the medium pressurizing pipe 301 to prevent the medium in the condenser 2 from flowing back into the medium pressurizing pipe 301; the second valve 315 is used to control the on-off of the outlet end of the medium pressurizing pipe 301.

[0048] The throttling pipeline 6 includes a throttling main pipe 601. The inlet end of the throttling main pipe 601 is communicated with the outlet end of the heat exchange coil in the condenser 2, and the other end of the throttling main pipe 601 is communicated with the inlet end of the heat exchange coil in the evaporator 1.

[0049] A third valve 602, a filter barrel 603, a throttling device 604, and a fourth valve 605 are sequentially connected in series along the flow direction of the medium on the throttling main pipe 601.

[0050] The third valve 602 is used to automatically control the on-off of the liquid inlet of the throttling main pipe 601, and the third valve 602 can also automatically adjust its opening degree to adjust the flow rate and flow velocity of the refrigerant in the throttling main pipe 601.

[0051] The filter barrel 603 is used to filter the refrigerant flowing in the throttling main pipe 601; the throttling device 604 is used to throttle and reduce the pressure of the refrigerant flowing in the throttling main pipe 601 to ensure the pressure difference between the condenser 2 and the evaporator 1, so that the liquid refrigerant in the evaporator 1 evaporates and absorbs heat at the required low pressure, thereby achieving the purpose of refrigeration and pressure reduction.

[0052] The fourth valve 605 is used to automatically control the on-off of the liquid outlet of the throttling main pipe 601, and the fourth valve 605 can also automatically adjust its opening degree to adjust the flow rate and flow velocity of the refrigerant in the throttling main pipe 601.

[0053] The cooling pipeline 4 includes a cooler 402. The inlet end of the cooler 402 is communicated with a cooling main pipe 401, and the inlet end of the cooling main pipe 401 is communicated with the heat exchange coil in the condenser 2.

[0054] A first cooling valve 403, a first filter 404, and a second cooling valve 405 are communicated with the cooling main pipe 401; the first cooling valve 403, the first filter 404, and the second cooling valve 405 are sequentially arranged along the flow direction of the medium.

[0055] The first cooling valve 403 is used to control the on-off of the inlet end of the cooling main pipe 401; the first filter 404 is used to filter the medium flowing in the cooling main pipe 401; the second cooling valve 405 is used to control the on-off of the inlet end of the cooler 402.

[0056] A cooling water inlet pipe 414 and a cooling water outlet pipe 415 are further arranged on the cooler 402, and the cooling water inlet pipe 414 and the cooling water outlet pipe 415 are respectively communicated with the cooling channels in the cooler 402.

[0057] The other ends of the cooling water inlet pipe 414 and the cooling water outlet pipe 415 are communicated with an external cooling water source.

[0058] The outlet end of the cooler 402 is connected to a first cooling branch pipe 410 , and the other end of the first cooling branch pipe 410 is connected to a cooling channel on the secondary compressor 303 through a plurality of first branch pipes.

[0059] The number of the first branch pipes matches the number of cooling channels on the secondary compressor 303 .

[0060] The first cooling branch pipe 410 is connected in series with a first sight glass 408 , and the first branch pipes are respectively connected in series with a first regulating valve 409 , which is used to control the on-off of the corresponding first branch pipe.

[0061] A cooling branch 406 is connected in series between the first filter 404 and the second cooling valve 405 on the cooling main pipe 401 , and the other end of the cooling branch 406 is communicated with the first cooling branch 410 .

[0062] The cooling branch 406 is connected in series with a third cooling valve 407 , and the third cooling valve 407 is used to control the on / off of the cooling branch 406 .

[0063] The first cooling branch pipe 410 is connected in series with a second cooling branch pipe 411 , and the other end of the second cooling branch pipe 411 is connected to the cooling channel on the first-stage compressor 302 through a plurality of second branch pipes.

[0064] The number of the second branch pipes matches the number of cooling channels on the first-stage compressor 302 .

[0065] The second cooling branch pipe 411 is connected in series with a second sight glass 412 , and the second branch pipes are respectively connected in series with a second regulating valve 413 , which is used to control the on / off of the corresponding second branch pipe.

[0066] A flash tank 5 is also provided on one side of the medium boosting pipe 301. The gas outlet end of the flash tank 5 is connected to a flash branch pipe 501. The other end of the flash branch pipe 501 is connected to the medium boosting pipe 301 at the inlet end of the secondary compressor 303. A fifth cooling valve 502 is connected in series to the flash branch pipe 501.

[0067] The outlet ends of the cooling channels of the first-stage compressor 302 and the second-stage compressor 303 are connected to a confluence main pipe 503 , and the other end of the confluence main pipe 503 is connected to the inlet end of the flash tank 5 .

[0068] A fourth cooling valve 505 is connected in series on the confluence main pipe 503 at an outlet end of the cooling flow channel close to the secondary compressor 303 .

[0069] The outlet end of the flash tank 5 is connected to a reflux main pipe 504 , and the other end of the reflux main pipe 504 is connected to the heat exchange coil in the evaporator 1 .

[0070] A sixth cooling valve 506 is connected in series on the reflux main pipe 504, and the sixth cooling valve 506 is used to control the on-off of the outlet end of the reflux main pipe 504.

[0071] With such a design, when in use, the variable-condition magnetic levitation multi-stage compression cooling cycle system has a heating condition in winter and a refrigeration condition in summer.

[0072] When the variable-condition magnetic levitation multi-stage compression cooling cycle system needs to heat in winter, it operates in the winter heating condition. At this time, the operation diagram of the cycle system is as Figure 1 shown. The condenser 2 is used as the user side to output hot water to achieve heating. The heat source inlet pipe 201 is communicated with the external heat source water, and the heat source outlet pipe 202 is communicated with the heating pipeline.

[0073] At this time, the external heat source water enters the condenser 2 through the heat source inlet pipe 201. At this time, the heat source water exchanges heat with the heat exchange coil in the condenser 2 to heat the heat source water, and then outputs hot water through the heat source outlet pipe 202 to achieve the heating operation.

[0074] The low-temperature and high-pressure refrigerant cooled in the heat exchange coil of the condenser 2 consists of two parts. Most of them enter the heat exchange coil of the evaporator 1 through the throttle main pipe 601, the third valve 602, the filter barrel 603, the throttling device 604 and the fourth valve 605.

[0075] After being throttled by the throttling device 604, the refrigerant becomes low-temperature and low-pressure. The refrigerant quickly evaporates into refrigerant gas by absorbing the heat on the heat source side in the evaporator 1. The low-temperature and low-pressure refrigerant gas at the outlet end of the evaporator 1 is transported into the medium pressurizing pipe 301, and then enters the suction end of the first-stage compressor 302 through the first valve 305 and is compressed and discharged into the outlet end. The low-temperature and medium-pressure refrigerant gas enters the suction end of the second-stage compressor 303 through the first electric valve 306 and is compressed. The compressed high-temperature and high-pressure refrigerant gas re-enters the condenser 2 through the check valve 314 and the second valve 315. During this process, the second electric valve 311 is in the closed state.

[0076] During this process, the user side of the condenser 2 outputs hot water for users to use; the heating cycle is completed reciprocally; and during this process, the first-stage compressor 302 and the second-stage compressor 303 can increase the pressure ratio of the single-stage compressor by more than 1 time through design matching, significantly increase the suction and discharge pressures and the operating range of the unit, and the system can adapt to the variable-condition operating range of the low-temperature heat pump unit.

[0077] When operating in the winter heating condition, the temperature of the magnetic levitation motor of the secondary compressor 303 is relatively high. At the same time, the temperature of the hot water on the user side is relatively high, and the temperature of the refrigerant flowing out from the outlet end of the condenser 2 is relatively high, which requires cooling through the cooling pipeline 4. At the same time, in order to reduce the superheat at the outlet of the secondary compressor 303 and increase the refrigerant flow rate, a flash evaporation structure is added to the cooling system to adjust the air supply to the suction port of the secondary compressor 303.

[0078] The working process of the cooling pipeline 4 is as follows: The first cooling valve 403 is opened, and the high-pressure and high-temperature refrigerant liquid discharged from the outlet end of the condenser 2 enters the cooling main pipe 401, and then enters the cooler 402 after passing through the first filter 404 and the second cooling valve 405 for cooling, and then is transported to the inlet ends of the cooling channels of the secondary compressor 303 and the primary compressor 302 through the first cooling branch pipe 410 and the second cooling branch pipe 411, and the flow rate of the refrigerant is controlled through the first regulating valve 409 and the second regulating valve 413 to control the temperature of the magnetic levitation motors of the secondary compressor 303 and the primary compressor 302; during this process, the third cooling valve 407 is in a closed state.

[0079] The refrigerant discharged from the outlet ends of the cooling channels of the secondary compressor 303 and the primary compressor 302 converges into the confluence main pipe 503, and then is transported by the confluence main pipe 503 to the flash tank 5 for heat exchange. The refrigerant gas that has completed gas-liquid separation in the flash tank 5 enters the inlet of the secondary compressor 303 through the flash branch pipe 501 and the fifth cooling valve 502 to participate in air supply.

[0080] The refrigerant liquid that has completed gas-liquid separation in the flash tank 5 flows back to the evaporator 1 through the return main pipe 504 and the sixth cooling valve 506. The refrigerant liquid is depressurized and absorbs heat in the evaporator 1 and then re-enters the circulation system; the cooler 402 cools the refrigerant liquid with low-temperature water.

[0081] When the variable-condition magnetic levitation multi-stage compression cooling circulation system needs to refrigerate in summer, it operates in the summer refrigeration condition. At this time, the operation diagram of the circulation system is as Figure 2 shown. The evaporator 1 is used as the user side to output chilled water to achieve refrigeration operation. The cold source inlet pipe 101 is connected to the external cold source water, and the cold source outlet pipe 102 is connected to the indoor refrigeration pipeline.

[0082] At this time, the external cold source water enters the evaporator 1 through the cold source inlet pipe 101. At this time, the cold source water exchanges heat with the heat exchange coil in the evaporator 1 to cool the cold source water, and then outputs chilled water through the cold source outlet pipe 102 to achieve refrigeration operation.

[0083] The low-temperature and high-pressure refrigerant cooled in the heat exchange coil of the condenser 2 consists of two parts. Most of it enters the heat exchange coil of the evaporator 1 through the throttle main pipe 601, the third valve 602, the filter barrel 603, the throttling device 604, and the fourth valve 605.

[0084] After being throttled by the throttling device 604, the refrigerant becomes low-temperature and low-pressure, and quickly evaporates into refrigerant gas by absorbing the heat on the user side in the evaporator 1. At this time, the evaporator 1 outputs cold water as the user side to provide low-temperature chilled water for indoor cooling.

[0085] The low-temperature and low-pressure refrigerant gas at the outlet end of the evaporator 1 is transported into the medium booster pipe 301, and then enters the suction end of the first-stage compressor 302 through the first valve 305 and is compressed and discharged into the outlet end. At this time, the first electric valve 306 is closed; the second electric valve 311 is opened, and the second-stage compressor 303 is in the closed state; at this time, the low-temperature and medium-pressure refrigerant gas discharged from the outlet end of the first-stage compressor 302 directly enters the condenser 2 through the branch booster pipe 304, the second electric valve 311, the check valve 314, and the second valve 315.

[0086] In the summer refrigeration condition, the first electric valve 306 and the second-stage compressor 303 are both in the closed state, and no second-stage compression is required.

[0087] Part of the refrigerant cooled in the condenser 2 enters the cooling main pipe 401. At this time, the second cooling valve 405 is in the closed state; the third cooling valve 407 is in the open state. The refrigerant in the cooling main pipe 401 is transported to the cooling flow path of the first-stage compressor 302 through the first cooling valve 403, the first filter 404, the cooling branch 406, the third cooling valve 407, the second cooling branch pipe 411, and the second regulating valve 413 to cool the magnetic levitation motor of the first-stage compressor 302.

[0088] The refrigerant discharged from the cooling flow path of the first-stage compressor 302 is transported to the flash tank 5 through the confluence main pipe 503, and then returns to the evaporator 1 through the return main pipe 504 and the sixth cooling valve 506.

[0089] During this cooling process, the second cooling valve 405, the fourth cooling valve 505, and the fifth cooling valve 502 are all in the closed state, and the refrigerant liquid does not need to be cooled continuously.

[0090] For those of ordinary skill in the art, according to the teachings of the present invention, without departing from the principles and spirit of the present invention, the changes, modifications, substitutions, and variations made to the embodiments still fall within the protection scope of the present invention.

Claims

1. A variable-condition magnetic levitation multi-stage compression cooling cycle system, comprising an evaporator (1) and a condenser (2), characterized in that: A multi-stage pressurization pipeline (3) and a throttling pipeline (6) are arranged between the evaporator (1) and the condenser (2). The inlet end of the multi-stage pressurization pipeline (3) is communicated with the outlet end of the heat exchange coil in the evaporator (1), and the outlet end of the multi-stage pressurization pipeline (3) is communicated with the inlet end of the heat exchange coil in the condenser (2). The inlet end of the throttling pipeline (6) is communicated with the outlet end of the heat exchange coil in the condenser (2), and the other end of the throttling pipeline (6) is communicated with the inlet end of the heat exchange coil in the evaporator (1); A cooling pipeline (4) is also connected in series on the heat exchange coil of the condenser (2), and the other end of the cooling pipeline (4) is sequentially communicated with the cooling flow channel of the magnetic levitation compressor on the multi-stage pressurization pipeline (3).

2. The variable-condition magnetic levitation multi-stage compression cooling cycle system according to claim 1, wherein: The multi-stage pressurization pipeline (3) includes a medium pressurization pipe (301). A first-stage compressor (302) and a second-stage compressor (303) are sequentially connected in series on the medium pressurization pipe (301). A branch pressurization pipe (304) is also connected in parallel on the medium pressurization pipe (301). The inlet end of the branch pressurization pipe (304) is communicated with the medium pressurization pipe (301) at the inlet and outlet ends of the second-stage compressor (303), and the outlet end of the branch pressurization pipe (304) is communicated with the medium pressurization pipe (301) at the outlet end of the second-stage compressor (303). After the branch pressurization pipe (304) is connected, the medium in the medium pressurization pipe (301) no longer enters the second-stage compressor (303).

3. A variable-condition magnetic levitation multi-stage compression cooling cycle system according to claim 2, characterized in that: A first valve (305), a first pressure sensor (307) and a first temperature sensor (308) are sequentially arranged on the medium pressurization pipe (301) between the evaporator (1) and the first-stage compressor (302) along the flow direction of the medium; A first electric valve (306), a second pressure sensor (309) and a second temperature sensor (310) are connected in series on the front side of the inlet end of the second-stage compressor (303) on the medium pressurization pipe (301); The first electric valve (306), the second pressure sensor (309) and the second temperature sensor (310) are sequentially arranged along the flow direction of the medium.

4. A variable-condition magnetic levitation multi-stage compression cooling cycle system according to claim 3, characterized in that: A second electric valve (311), a third pressure sensor (312) and a third temperature sensor (313) are sequentially arranged on the branch pressurization pipe (304) along the flow direction of the medium. The second electric valve (311) is used to control the on-off of the branch pressurization pipe (304).

5. A variable-condition magnetic levitation multi-stage compression cooling cycle system according to claim 4, characterized in that: A check valve (314) and a second valve (315) are connected in series at a position on the medium pressurization pipe (301) close to the condenser (2). The check valve (314) and the second valve (315) are sequentially arranged along the flow direction of the medium.

6. The variable-condition magnetic levitation multi-stage compression cooling cycle system according to claim 5, characterized in that: The throttling pipeline (6) includes a throttling main pipe (601). A third valve (602), a filter barrel (603), a throttling device (604) and a fourth valve (605) are sequentially connected in series on the throttling main pipe (601) along the flow direction of the medium.

7. A variable operating condition magnetic levitation multi-stage compression cooling cycle system according to claim 6, characterized in that: The cooling pipeline (4) includes a cooler (402). The inlet end of the cooler (402) is communicated with a cooling main pipe (401), and the inlet end of the cooling main pipe (401) is communicated with the heat exchange coil in the condenser (2); a first cooling valve (403), a first filter (404) and a second cooling valve (405) are arranged in sequence along the flow direction of the medium on the cooling main pipe (401). A first cooling branch pipe (410) is communicated with the outlet end of the cooler (402), and the other end of the first cooling branch pipe (410) is communicated with the cooling flow path on the secondary compressor (303) through a plurality of first branch pipes; a first regulating valve (409) is connected in series on each first branch pipe. A second cooling branch pipe (411) is connected in series on the first cooling branch pipe (410), and the other end of the second cooling branch pipe (411) is communicated with the cooling flow path on the primary compressor (302) through a plurality of second branch pipes; a second regulating valve (413) is connected in series on each second branch pipe.

8. A variable-condition magnetic levitation multi-stage compression cooling cycle system according to claim 7, characterized in that: A cooling branch (406) is connected in series between the first filter (404) and the second cooling valve (405) on the cooling main pipe (401), and the other end of the cooling branch (406) is communicated with the first cooling branch pipe (410); a third cooling valve (407) is connected in series on the cooling branch (406), and the third cooling valve (407) is used to control the on-off of the cooling branch (406).

9. A variable operating condition magnetic levitation multi-stage compression cooling cycle system according to claim 8, characterized in that: A flash tank (5) is further arranged on one side of the medium booster pipe (301). The gas outlet end of the flash tank (5) is communicated with a flash branch pipe (501), and the other end of the flash branch pipe (501) is communicated with the medium booster pipe (301) at the inlet end of the secondary compressor (303); a fifth cooling valve (502) is connected in series on the flash branch pipe (501).

10. A variable-condition magnetic levitation multi-stage compression cooling cycle system according to claim 9, characterized in that: The outlet ends of the cooling flow paths of the primary compressor (302) and the secondary compressor (303) are communicated with a confluence main pipe (503), and the other end of the confluence main pipe (503) is communicated with the inlet end of the flash tank (5); a fourth cooling valve (505) is connected in series at the outlet end of the cooling flow path of the confluence main pipe (503) close to the secondary compressor (303). The outlet end of the flash tank (5) is communicated with a return main pipe (504), and the other end of the return main pipe (504) is communicated with the heat exchange coil in the evaporator (1); a sixth cooling valve (506) is connected in series on the return main pipe (504).

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