Wide-operating-condition, year-round refrigeration type evaporative cooling magnetic suspension refrigeration unit and control method

Abstract

The invention discloses a wide-operating-condition year-round refrigeration type evaporative cooling magnetic suspension refrigeration unit and a control method, comprising a plurality of direct evaporation coils, wherein the output ends of the plurality of direct evaporation coils are connected to the inlet end of a vapor-liquid separator after being collected into one pipeline through a plurality of pipelines, the gas outlet and the auxiliary gas outlet of the vapor-liquid separator are respectively connected to the air inlet and the air supply port of the magnetic suspension compressor through pipelines, the exhaust port of the magnetic suspension compressor is connected to the inlet end of the evaporative cooling condenser through pipelines, the outlet end of the evaporative cooling condenser is connected to the inlet end of the liquid storage tank through pipelines, the outlet end of the liquid storage tank is connected to the inlet end of the filter drier, and the outlet end of the filter drier is respectively connected to the liquid injection interface of the magnetic suspension compressor and the inlet ends of a plurality of direct evaporation coils through pipelines. The evaporation temperature range of the unit of the invention can be adjusted within the range of -5°C to 18°C, which can meet the needs of multiple operating conditions. The magnetic suspension compressor uses magnetic suspension technology to reduce the mechanical friction of moving parts, which greatly improves the service life of the unit.

Description

Technical Field

[0001] The invention belongs to the technical field of refrigeration and air-conditioning equipment, and in particular relates to a wide-operating-condition, year-round refrigeration type evaporative cooling magnetic suspension refrigeration unit and a control method. Background Art

[0002] With the development of my country's economy and the continuous acceleration of the industrialization process. The requirements of various industries for refrigeration and air-conditioning equipment are also constantly increasing, and existing equipment can no longer meet higher standards and energy-saving requirements. In the magnetic levitation refrigeration units of the prior art, the cooling method is mostly water-cooled or air-cooled, and the cooling efficiency is lower than that of evaporative cooling. The evaporator is a full liquid or plate evaporator to produce cold water for use. The evaporation temperature adjustment range is limited, and at low evaporation temperatures, antifreeze needs to be added to the chilled water. When water cooling is used for cooling, when the ambient temperature is below 0°C and refrigeration is required, the problem of antifreeze must also be solved.

[0003] Taking the agricultural field as an example, on the one hand, traditional refrigeration and air-conditioning equipment is designed to meet a specific working condition, and its adjustable evaporation temperature range is small, which cannot meet the temperature change requirements during crop growth; on the other hand, its energy consumption is also high. Summary of the invention

[0004] The existing refrigeration and air-conditioning equipment has a limited adjustment range for the evaporation temperature, which cannot meet the requirements of large temperature and load changes in certain fields. Refrigeration at low ambient temperatures needs to consider antifreeze, and the energy consumption is high. The present invention proposes a wide-operating-condition, year-round refrigeration evaporative cooling magnetic levitation refrigeration unit and control method, which has high refrigeration operation efficiency and a wide adjustable range of evaporation temperature, which can be adjusted freely within the range of -5°C to 18°C. Compared with the traditional unit with an adjustment range of ±5°C, the flexibility of use is greatly increased.

[0005] In order to achieve the above purpose, the present invention adopts the following technical methods:

[0006] The evaporative cooling magnetic suspension refrigeration unit of wide-operating-condition year-round refrigeration type comprises a plurality of direct evaporation coils, the output ends of the plurality of direct evaporation coils are connected to the inlet end of a vapor-liquid separator after being collected into one pipeline through a plurality of pipelines, the gas outlet and the auxiliary gas outlet of the vapor-liquid separator are respectively connected to the air inlet and the air supply outlet of the magnetic suspension compressor through pipelines, the exhaust port of the magnetic suspension compressor is connected to the inlet end of an evaporative cooling condenser through a pipeline, the outlet end of the evaporative cooling condenser is connected to the inlet end of a liquid storage tank through a pipeline, the outlet end of the liquid storage tank is connected to the inlet end of a drying filter, and the outlet end of the drying filter is respectively connected to the liquid injection interface of the magnetic suspension compressor and the inlet ends of a plurality of direct evaporation coils through pipelines; the opening degree of the electronic expansion valve of the direct evaporation coil is determined by the difference between the indoor set temperature and the indoor actual temperature. It is determined that when the actual indoor temperature is greater than the set temperature, the electronic expansion valve is controlled to open and the opening of the electronic expansion valve is adjusted through the PLC controller; when the actual indoor temperature is lower than the set temperature, the opening of the electronic expansion valve is controlled to decrease through the PLC controller; the opening, closing and frequency adjustment of the magnetic levitation compressor are controlled by the suction pressure of the magnetic levitation compressor. When any electronic expansion valve on the refrigeration unit is opened, the magnetic levitation compressor is turned on, and when all the electronic expansion valves are closed, the magnetic levitation compressor is turned off; the frequency of the magnetic levitation compressor, i.e. the load, is adjusted according to the suction pressure. When the suction pressure is lower than the set value, the magnetic levitation compressor is unloaded to reduce the frequency of the magnetic levitation compressor motor; when the suction pressure is greater than the set value, the magnetic levitation compressor is loaded to increase the frequency of the magnetic levitation compressor motor.

[0007] A solenoid valve 1 is installed on the pipeline between the direct evaporation coil and the vapor-liquid separator; a needle valve 1 is installed on the vapor-liquid separator, a butterfly valve is installed on the pipeline between the gas outlet of the vapor-liquid separator and the air intake of the magnetic levitation compressor, and a pressure setting valve is installed on the pipeline between the auxiliary air port of the vapor-liquid separator and the air supply port of the magnetic levitation compressor; a one-way valve is installed on the pipeline between the magnetic levitation compressor and the evaporative cooling condenser, and a needle valve 2 and a solenoid valve 2 are installed in sequence on the pipeline between the evaporative cooling condenser and the liquid storage tank; a safety valve is installed on the liquid storage tank, a solenoid valve 3 is installed on the pipeline between the liquid storage tank and the drying filter, an angle valve is installed on the pipeline between the drying filter and the magnetic levitation compressor, and the drying filter is connected to the inlet end of the direct evaporation coil through the pipeline, the solenoid valve 4 and the electronic expansion valve.

[0008] The evaporative cooling condenser includes a shell, a water tank is arranged at the bottom of the shell, a float valve is arranged in the water tank, the water tank is connected with the nozzle on the top through a spray cooling water pump, a water treatment instrument, and a condensing coil is arranged below the nozzle, the condensing coil adopts an aluminum-zinc-coated steel pipe, and the wind and water downstream heat exchange is performed, and the addition of fillers enhances the cooling water cooling effect, fillers are arranged between the condensing coil and the water tank, and an axial flow fan is installed on the top of the shell, the axial flow fan adopts a combination of variable frequency and fixed frequency, and automatically adjusts the air volume according to the load and environmental changes to ensure the safety of the unit and energy-saving operation; the opening and closing of the axial flow fan and the adjustment of the air volume are controlled by the condensing pressure, when the condensing pressure is lower than the set value, the air volume of the axial flow fan is reduced, and when the condensing pressure is higher than the set value, the axial flow fan As the air volume increases, the axial flow fan can adopt a fixed frequency plus variable frequency configuration to achieve stepless adjustment of the air volume; when the evaporative condenser is working, the superheated refrigerant vapor enters the top of the condensing coil, and the cooling water is pumped to the upper part of the condensing coil by the water pump, and is evenly sprayed on the surface of the condensing coil through the nozzle to form a very thin water film; the high-temperature refrigerant enters from the upper header of the condensing coil and is distributed to each serpentine tube to release heat; the air is sent to the cooling unit by the axial flow fan, and the high-temperature refrigerant gas in the tube first transfers the heat to the water film through the tube wall, causing the water film to evaporate, and when the water film evaporates into water vapor, it transfers part of the heat together with the water vapor itself to the air in the form of latent heat; it is extracted by the axial flow fan; the cooling water that has not been evaporated drops into the water tank at the bottom for circulation by the water pump.

[0009] The axial flow fan on the top of the evaporative cooling condenser can adopt the variable frequency plus fixed frequency mode. When the ambient temperature and the terminal load change, the air volume can be adjusted according to the system pressure, ambient temperature and condensing temperature. The unit includes the following operating modes: the first one, when the ambient temperature is higher than -5℃, the cooling spray water pump is turned on, and the axial flow fan of the evaporative cooling condenser is adjusted by the system pressure and condensing temperature. The second one, when the ambient temperature is lower than -5℃, the cooling spray water pump is turned off, and the evaporative cooling condenser operates under dry conditions to prevent water from freezing, and the axial flow fan of the evaporative cooling condenser is adjusted by the system pressure and condensing temperature.

[0010] The control method of the evaporative cooling magnetic suspension refrigeration unit with wide working conditions and year-round refrigeration includes the following steps:

[0011] Step 1, when the actual indoor temperature is higher than the set temperature, the temperature sensor outputs a signal to the indoor unit fan and the electronic expansion valve actuator. The indoor unit fan is a direct evaporation coil fan, which can be an axial flow fan or a centrifugal fan. The indoor unit fan and the electronic expansion valve are turned on. At this time, the pressure sensor of the magnetic suspension compressor outputs the suction pressure signal to the PLC controller to control the opening of the magnetic suspension compressor. The refrigerant enters the vapor-liquid separator after evaporating and absorbing heat in the direct evaporation coil. The gas outlet of the vapor-liquid separator is connected to the suction port of the magnetic suspension compressor. The frequency of the magnetic suspension compressor, that is, the load, is adjusted according to the suction pressure. When the refrigerant flow increases and the suction pressure increases, the magnetic suspension compressor is loaded to increase the compressor motor frequency; when the refrigerant flow decreases and the suction pressure decreases, the magnetic suspension compressor is unloaded to reduce the compressor motor frequency;

[0012] Step 2, the exhaust port of the magnetic suspension compressor is connected to the evaporative cooling condenser through a one-way valve, and the high-temperature and high-pressure refrigerant processed by the compressor is sent to the condensing coil of the evaporative cooling condenser through the one-way valve to complete the condensation and heat release process; after the magnetic suspension compressor is turned on, the axial flow fan and the spray cooling water pump of the evaporative cooling condenser are turned on according to the ambient temperature and the condensation pressure; when the ambient temperature is higher than -5°C, the evaporative cooling condenser operates in a wet condition, that is, the cooling spray water pump is turned on, and the cooling water is sprayed onto the condensing coil through the nozzle. A part of the cooling water evaporates and takes away the heat in the form of latent heat. The number and frequency of the axial flow fan are controlled by the condensation pressure. The axial flow fan adopts a fixed frequency plus variable frequency configuration to achieve variable air volume adjustment according to the change of condensation pressure; when the ambient temperature is lower than -5°C, the evaporative cooling condenser operates in a dry condition, that is, the cooling spray water pump is turned off, the condenser has no spray water, and the condensing coil is cooled by air. The air volume change is also controlled by the condensation pressure. The dry condition operation of the evaporative cooling condenser ensures that there will be no icing problem during low ambient temperature refrigeration operation;

[0013] Step 3, the medium-temperature and high-pressure refrigerant condensed by the evaporative cooling condenser is sent to the liquid storage tank. The medium-temperature and high-pressure refrigerant liquid is divided into two paths through a drying filter. The main path passes through an electronic expansion valve and is sent to the direct evaporator coil after throttling and pressure reduction. The refrigerant evaporates and cools in the direct evaporator coil to complete the refrigeration process; the refrigerant flow entering the direct evaporator coil is controlled by the electronic expansion valve; the other branch refrigerant is sent to the compressor spray cooling interface through an angle valve for cooling the compressor motor and electronic components, and the angle valve opening is controlled by the motor temperature.

[0014] The beneficial effects of the present invention are:

[0015] 1. The evaporation temperature range of the unit of the present invention can be adjusted within -5℃~18℃, which can meet the needs of multiple working conditions. Compared with traditional water-cooled air conditioners, it can save 35% to 40% of energy when the ambient temperature is above -5℃; it can save 40% to 50% of energy when the ambient temperature is below -5℃.

[0016] 2. The compressor of the unit of the present invention adopts magnetic suspension technology, the condenser adopts a highly efficient evaporative cooling condenser, and the evaporator adopts a direct evaporative coil. Compared with the water system, the chilled water pump is reduced, the power and head of the cooling water pump are also reduced, and the heat exchange loss is reduced without the secondary heat exchange process, and the overall operation efficiency of the unit is significantly improved.

[0017] 3. The antifreeze problem of year-round refrigeration in cold areas in winter has always been a problem in the water system. The unit mentioned in the present invention can operate in dry conditions and natural cooling in winter. The evaporative condenser uses water as a medium and uses the evaporation of water to take away the condensation heat of the vapor refrigerant. It is the most efficient condensation method. Its efficiency is more than 5 times that of the air-cooled condenser and more than 1.5 times that of the water-cooled condenser. It also consumes less water, about 1 / 3 of the water-cooled condenser. The water pump is integrated in the evaporative condenser, with a head of 3 to 5m, and power consumption can be saved by more than 30%. Under the winter working conditions of the unit of the present invention, the water in the evaporative cooling condenser can be completely drained, and there is no need to worry about this problem.

[0018] 4. The evaporator uses a direct evaporation coil to directly exchange heat with the air in the air-conditioned room to cool the air-conditioned room. This reduces the secondary heat exchange process of the system. Compared with the chilled water system, the chilled water pump is omitted to save electricity, and there is no need to worry about antifreeze problems at low evaporation temperatures.

[0019] 5. The magnetic suspension compressor uses magnetic suspension technology to reduce mechanical friction of moving parts, greatly increasing the service life of the unit. Its oil-free design also greatly reduces system components, improves the system COP value, and significantly reduces maintenance costs. Its low starting current (only 1A current) has no impact on the power grid, and no soft starter is required. Especially at partial load, the energy efficiency ratio advantage is more obvious. It is suitable for various places with large load changes, and can save 50% of operating costs compared with traditional chillers. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the wide-operating-condition, year-round refrigeration evaporative cooling magnetic suspension refrigeration unit and control method of the present invention;

[0021] 1-magnetic levitation compressor, 2-check valve, 3-evaporative cooling condenser, 4-solenoid valve 2, 5-liquid storage tank, 6-solenoid valve 3, 7-drying filter, 8-angle valve, 9-solenoid valve 4, 10-electronic expansion valve, 11-direct evaporation coil, 12-solenoid valve 1, 13-gas-liquid separator, 14-butterfly valve, 15-pressure setting valve, 16-needle valve 2, 17-needle valve 1, 18-float valve, 19-axial flow fan, 20-nozzle, 21-condensing coil, 22-filling, 23-water tank, 24-spray cooling water pump, 25-water treatment instrument, 26-safety valve. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0023] like Figure 1 As shown, a wide-operating-condition, year-round evaporative cooling magnetic suspension refrigeration unit comprises two direct evaporation coils 11, the output ends of the two direct evaporation coils 11 are connected to the inlet end of a vapor-liquid separator 13 after being collected into one pipeline through two pipelines, the gas outlet and the auxiliary gas outlet of the vapor-liquid separator 13 are respectively connected to the air intake and the air supply outlet of the magnetic suspension compressor 1 through pipelines, the exhaust port of the magnetic suspension compressor 1 is connected to the inlet end of an evaporative cooling condenser 3 through a pipeline, the outlet end of the evaporative cooling condenser 3 is connected to the inlet end of a liquid storage tank 5 through a pipeline, the outlet end of the liquid storage tank 5 is connected to the inlet end of a drying filter 7, and the outlet end of the drying filter 7 is respectively connected to the liquid injection interface of the magnetic suspension compressor 1 and the inlet end of several direct evaporation coils 11 through pipelines; the opening degree of the electronic expansion valve 10 of the direct evaporation coil 11 is determined by the indoor set temperature and the indoor actual temperature. The temperature difference determines that when the actual indoor temperature is greater than the set temperature, the electronic expansion valve 10 is controlled to open and the opening of the electronic expansion valve 10 is adjusted through the PLC controller; when the actual indoor temperature is less than the set temperature, the opening of the electronic expansion valve 10 is controlled to decrease through the PLC controller; the opening, closing and frequency adjustment of the magnetic levitation compressor 1 are controlled by the suction pressure of the magnetic levitation compressor 1. When any electronic expansion valve 10 on the refrigeration unit is opened, the magnetic levitation compressor 1 is turned on, and when all the electronic expansion valves 10 are closed, the magnetic levitation compressor 1 is turned off; the frequency of the magnetic levitation compressor 1, i.e. the load, is adjusted according to the suction pressure. When the suction pressure is lower than the set value, the magnetic levitation compressor 1 is unloaded to reduce the motor frequency of the magnetic levitation compressor 1; when the suction pressure is greater than the set value, the magnetic levitation compressor 1 is loaded to increase the motor frequency of the magnetic levitation compressor 1.

[0024] A solenoid valve 12 is installed on the pipeline between the direct evaporation coil 11 and the vapor-liquid separator 13; a needle valve 17 is installed on the vapor-liquid separator 13, a butterfly valve 14 is installed on the pipeline between the gas outlet of the vapor-liquid separator 13 and the air intake of the magnetic suspension compressor 1, and a pressure setting valve 15 is installed on the pipeline between the auxiliary air port of the vapor-liquid separator 13 and the air supply port of the magnetic suspension compressor 1; a one-way valve 2 is installed on the pipeline between the magnetic suspension compressor 1 and the evaporative cooling condenser 3, and a needle valve 2 16 and a solenoid valve 2 4 are installed in sequence on the pipeline between the evaporative cooling condenser 3 and the liquid storage tank 5; a safety valve 26 is installed on the liquid storage tank 5, a solenoid valve 3 6 is installed on the pipeline between the liquid storage tank 5 and the drying filter 7, an angle valve 8 is installed on the pipeline between the drying filter 7 and the magnetic suspension compressor 1, and the drying filter 7 is connected to the inlet end of the direct evaporation coil 11 through a pipeline, a solenoid valve 4 9 and an electronic expansion valve 10.

[0025] The evaporative cooling condenser 3 includes a shell, a water tank 23 is arranged at the bottom of the shell, a float valve 18 is arranged in the water tank 23, the water tank 23 is connected to the nozzle 20 at the top through a spray cooling water pump 24, a water treatment instrument 25, and a condensing coil 21 is arranged below the nozzle 20. The condensing coil 21 adopts an aluminum-zinc-coated steel pipe, and the wind and water downstream heat exchange is increased. The filler 22 is added to enhance the cooling water cooling effect. The filler 22 is arranged between the condensing coil 21 and the water tank 23. An axial flow fan 19 is installed on the top of the shell. The axial flow fan 19 adopts a combination of variable frequency and fixed frequency to automatically adjust the air volume according to the load and environmental changes to ensure the safety of the unit and energy-saving operation; the opening and closing of the axial flow fan 19 and the adjustment of the air volume are controlled by the condensing pressure. When the condensing pressure is lower than the set value, the air volume of the axial flow fan 19 is reduced, and when the condensing pressure is higher than When the set value is reached, the air volume of the axial flow fan 19 increases. The axial flow fan 19 can adopt a fixed frequency plus variable frequency configuration to achieve stepless adjustment of the air volume; when the evaporative condenser is working, the superheated refrigerant vapor enters the top of the condensing coil 21, and the cooling water is pumped to the upper part of the condensing coil 21 by the water pump, and is evenly sprayed on the surface of the condensing coil 21 through the nozzle to form a very thin water film; the high-temperature refrigerant enters from the upper header of the condensing coil 21 and is distributed to each serpentine tube to release heat; the air is sent to the high-temperature refrigerant gas in the cooling unit tube by the axial flow fan 19 first transfers the heat to the water film through the tube wall, causing the water film to evaporate, and when the water film evaporates into water vapor, it transfers part of the heat together with the water vapor itself to the air in the form of latent heat; it is extracted by the axial flow fan 19; the cooling water that has not been evaporated drops into the lower water tank 23 for circulation by the water pump.

[0026] The axial flow fan 19 at the top of the evaporative cooling condenser 3 can adopt a variable frequency plus fixed frequency mode. When the ambient temperature and the terminal load change, the air volume can be adjusted according to the system pressure, ambient temperature and condensing temperature. The unit includes the following operating modes: the first one, when the ambient temperature is higher than -5°C, the cooling spray water pump is turned on, and the axial flow fan 19 of the evaporative cooling condenser 3 is adjusted according to the system pressure and condensing temperature. The second one, when the ambient temperature is lower than -5°C, the cooling spray water pump is turned off, and the evaporative cooling condenser 3 operates under dry conditions to prevent water from freezing, and the axial flow fan 19 of the evaporative cooling condenser 3 is adjusted according to the system pressure and condensing temperature.

[0027] The control method of the evaporative cooling magnetic suspension refrigeration unit with wide working conditions and year-round refrigeration includes the following steps:

[0028] Step 1, when the actual indoor temperature is higher than the set temperature, the temperature sensor outputs a signal to the indoor unit fan and the electronic expansion valve 10 actuator, the indoor unit fan is the direct evaporation coil 11 fan, which can be an axial flow fan or a centrifugal fan, the indoor unit fan and the electronic expansion valve 10 are turned on, at this time the pressure sensor of the magnetic suspension compressor 1 outputs the suction pressure signal to the PLC controller to control the opening of the magnetic suspension compressor 1, the refrigerant enters the vapor-liquid separator 13 after evaporating and absorbing heat in the direct evaporation coil 11, the gas outlet of the vapor-liquid separator 13 is connected to the suction port of the magnetic suspension compressor 1, the frequency of the magnetic suspension compressor 1, that is, the load is adjusted according to the suction pressure, when the refrigerant flow increases and the suction pressure increases, the magnetic suspension compressor 1 is loaded to increase the compressor motor frequency; when the refrigerant flow decreases and the suction pressure decreases, the magnetic suspension compressor 1 is unloaded to reduce the compressor motor frequency;

[0029] Step 2: The exhaust port of the magnetic levitation compressor 1 is connected to the evaporative cooling condenser 3 through the one-way valve 2, and the high-temperature and high-pressure refrigerant processed by the compressor is sent to the condensing coil 21 of the evaporative cooling condenser 3 through the one-way valve 2 to complete the condensation and heat release process; after the magnetic levitation compressor 1 is turned on, the axial flow fan 19 and the spray cooling water pump 24 of the evaporative cooling condenser 3 are controlled to be turned on according to the ambient temperature and the condensation pressure; when the ambient temperature is higher than -5°C, the evaporative cooling condenser 3 is operated in wet conditions, that is, the cooling spray water pump is turned on, and the cooling water is sprayed to the condensing coil 2 through the nozzle 20 1, a part of the cooling water evaporates and takes away the heat in the form of latent heat, and the opening quantity and frequency of the axial flow fan 19 are controlled by the condensing pressure. The axial flow fan 19 adopts a fixed frequency plus variable frequency configuration to achieve variable air volume adjustment according to the change of condensing pressure; when the ambient temperature is lower than -5°C, the evaporative cooling condenser 3 operates in dry condition, that is, the cooling spray water pump is turned off, and the condenser has no spray water. The condensing coil 21 is cooled by air, and the air volume change is also controlled by the condensing pressure. The dry condition operation of the evaporative cooling condenser 3 ensures that there will be no icing problem during low ambient temperature refrigeration operation;

[0030] Step 3, the medium-temperature and high-pressure refrigerant condensed by the evaporative cooling condenser 3 is sent to the liquid storage tank 5. The medium-temperature and high-pressure refrigerant liquid is divided into two paths through the drying filter 7. The main path passes through the electronic expansion valve 10, and is sent to the direct evaporation coil 11 after throttling and reducing the pressure. The refrigerant evaporates and cools in the direct evaporation coil 11 to complete the refrigeration process; the refrigerant flow entering the direct evaporation coil 11 is controlled by the electronic expansion valve 10; the refrigerant in the other branch is sent to the compressor spray cooling interface through the angle valve 8, which is used to cool the compressor motor and electronic components, and the opening of the angle valve 8 is controlled by the motor temperature.

Claims

1. A wide range of operating conditions and year-round refrigeration type evaporative cooling magnetic suspension refrigeration unit, characterized in that: It comprises a plurality of direct evaporation coils, the output ends of the plurality of direct evaporation coils are connected to the inlet end of the vapor-liquid separator after being collected into one pipeline through a plurality of pipelines, the gas outlet and the auxiliary gas outlet of the vapor-liquid separator are respectively connected to the air intake and the air supply outlet of the magnetic suspension compressor through pipelines, the exhaust port of the magnetic suspension compressor is connected to the inlet end of the evaporative cooling condenser through pipelines, the outlet end of the evaporative cooling condenser is connected to the inlet end of the liquid storage tank through pipelines, the outlet end of the liquid storage tank is connected to the inlet end of the drying filter, and the outlet end of the drying filter is respectively connected to the liquid spray interface of the magnetic suspension compressor and the inlet ends of the plurality of direct evaporation coils through pipelines; A solenoid valve 1 is installed on the pipeline between the direct evaporation coil and the vapor-liquid separator; a needle valve 1 is installed on the vapor-liquid separator, a butterfly valve is installed on the pipeline between the gas outlet of the vapor-liquid separator and the air intake of the magnetic suspension compressor, and a pressure setting valve is installed on the pipeline between the auxiliary gas port of the vapor-liquid separator and the gas supply port of the magnetic suspension compressor; a one-way valve is installed on the pipeline between the magnetic suspension compressor and the evaporative cooling condenser, and a needle valve 2 and a solenoid valve 2 are installed in sequence on the pipeline between the evaporative cooling condenser and the liquid storage tank; a safety valve is installed on the liquid storage tank, a solenoid valve 3 is installed on the pipeline between the liquid storage tank and the drying filter, an angle valve is installed on the pipeline between the drying filter and the magnetic suspension compressor, and the drying filter is connected to the inlet end of the direct evaporation coil through the pipeline, the solenoid valve 4 and the electronic expansion valve respectively; The evaporative cooling condenser includes a shell, a water tank is arranged at the bottom of the shell, a float valve is arranged in the water tank, the water tank is connected with the nozzle at the top through a spray cooling water pump, a water treatment instrument, a condensing coil is arranged below the nozzle, a filler is arranged between the condensing coil and the water tank, and an axial flow fan is installed on the top of the shell.

2. The wide-operating-condition, year-round refrigeration evaporative cooling magnetic suspension refrigeration unit according to claim 1 is characterized in that: The axial flow fan on the top of the evaporative cooling condenser can adopt the variable frequency plus fixed frequency mode. When the ambient temperature and the terminal load change, the air volume can be adjusted according to the system pressure, ambient temperature and condensing temperature. The unit includes the following operating modes: the first one, when the ambient temperature is higher than -5℃, the cooling spray water pump is turned on, and the axial flow fan of the evaporative cooling condenser is adjusted by the system pressure and condensing temperature. The second one, when the ambient temperature is lower than -5℃, the cooling spray water pump is turned off, and the evaporative cooling condenser operates under dry conditions to prevent water from freezing, and the axial flow fan of the evaporative cooling condenser is adjusted by the system pressure and condensing temperature.

3. A control method for the wide-operating-condition, year-round evaporative cooling magnetic levitation refrigeration unit according to claim 1, characterized in that: The following steps are involved: Step 1, when the actual indoor temperature is higher than the set temperature, the temperature sensor outputs a signal to the indoor unit fan and the electronic expansion valve actuator. The indoor unit fan is a direct evaporation coil fan, which can be an axial flow fan or a centrifugal fan. The indoor unit fan and the electronic expansion valve are turned on. At this time, the pressure sensor of the magnetic suspension compressor outputs the suction pressure signal to the PLC controller to control the opening of the magnetic suspension compressor. The refrigerant enters the vapor-liquid separator after evaporating and absorbing heat in the direct evaporation coil. The gas outlet of the vapor-liquid separator is connected to the suction port of the magnetic suspension compressor. The frequency of the magnetic suspension compressor, that is, the load, is adjusted according to the suction pressure. When the refrigerant flow increases and the suction pressure increases, the magnetic suspension compressor is loaded to increase the compressor motor frequency; when the refrigerant flow decreases and the suction pressure decreases, the magnetic suspension compressor is unloaded to reduce the compressor motor frequency; Step 2, the exhaust port of the magnetic suspension compressor is connected to the evaporative cooling condenser through a one-way valve, and the high-temperature and high-pressure refrigerant processed by the compressor is sent to the condensing coil of the evaporative cooling condenser through the one-way valve to complete the condensation and heat release process; after the magnetic suspension compressor is turned on, the axial flow fan and the spray cooling water pump of the evaporative cooling condenser are turned on according to the ambient temperature and the condensation pressure; when the ambient temperature is higher than -5°C, the evaporative cooling condenser operates in a wet condition, that is, the cooling spray water pump is turned on, and the cooling water is sprayed onto the condensing coil through the nozzle. A part of the cooling water evaporates and takes away the heat in the form of latent heat. The number and frequency of the axial flow fan are controlled by the condensation pressure. The axial flow fan adopts a fixed frequency plus variable frequency configuration to achieve variable air volume adjustment according to the change of condensation pressure; when the ambient temperature is lower than -5°C, the evaporative cooling condenser operates in a dry condition, that is, the cooling spray water pump is turned off, the condenser has no spray water, and the condensing coil is cooled by air. The air volume change is also controlled by the condensation pressure. The dry condition operation of the evaporative cooling condenser ensures that there will be no icing problem during low ambient temperature refrigeration operation; Step 3, the medium-temperature and high-pressure refrigerant condensed by the evaporative cooling condenser is sent to the liquid storage tank. The medium-temperature and high-pressure refrigerant liquid is divided into two paths through a drying filter. The main path passes through an electronic expansion valve and is sent to the direct evaporation coil after throttling and pressure reduction. The refrigerant evaporates and cools in the direct evaporation coil to complete the refrigeration process; The refrigerant flow entering the direct evaporation coil is controlled by an electronic expansion valve; the refrigerant in another branch is sent to the compressor spray cooling interface through an angle valve to cool the compressor motor and electronic components, and the angle valve opening is controlled by the motor temperature.

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