A control method of a gas-fluorine integrated magnetic suspension unit with natural cooling

Abstract

The application relates to a control method of a gas-fluorine integrated magnetic suspension unit with natural cooling. The system comprises a magnetic suspension gas pump, a condenser, an evaporator, a liquid pump, a valve and a control unit. The control unit selects a running mode according to the difference between the ambient temperature and the water outlet temperature set value: when the difference is less than or equal to the liquid pump refrigeration set value, the liquid pump refrigeration mode is started; when the difference is greater than or equal to the gas pump refrigeration set value, the gas pump refrigeration mode is started; and when the difference is between the two, the mixed refrigeration mode is started. The scheme can flexibly switch modes, improve energy efficiency and economy.

Description

Technical Field

[0001] This application relates to the field of refrigeration technology, and more specifically, to a control method for an integrated gas-fluorine magnetic levitation unit with natural cooling. Background Technology

[0002] Data centers, as critical infrastructure, require continuous operation year-round. Their equipment has a high heat density, and the energy consumption of their cooling systems accounts for a significant proportion of overall operating costs. To address this high energy consumption challenge, natural cooling technology is widely adopted. This technology utilizes low-temperature outdoor air as a cold source, driving a refrigerant pump (liquid pump) to circulate the refrigerant when the ambient temperature is suitable, thereby reducing or stopping the operation of the compressor (air pump) and achieving energy savings. Currently, mainstream data center cooling units only support two operating modes: mechanical compressor cooling (air pump cooling) and liquid pump natural cooling. During high-temperature seasons, air pump cooling is relied upon to meet high load demands, while during low-temperature seasons, liquid pump cooling is switched to and the air pump is shut down. However, during the transitional seasons of spring and autumn, when outdoor ambient temperatures are in the moderate range, using only air pump cooling mode results in high energy consumption, while using only liquid pump cooling mode is insufficient to provide adequate cooling capacity, leading to an inability to balance energy efficiency and cooling capacity. Existing technologies lack a hybrid cooling mechanism for this transitional operating condition, failing to integrate the synergistic effect of air pumps and liquid pumps, resulting in the inability to fully realize energy efficiency potential.

[0003] Further analysis revealed significant limitations in the existing control strategy. Its regulation logic is overly simplified, typically relying solely on a single parameter—outlet water temperature—to execute equipment start-up / shutdown or basic capacity adjustments, failing to implement refined multi-parameter coordinated control for different operating modes. In air pump cooling mode, the throttle valve opening needs to respond in real-time to changes in evaporator liquid level to avoid refrigerant backflow or overheating risks. In mixed cooling mode, the liquid pump speed should dynamically match the evaporator liquid level to maintain stable air pump suction superheat. In liquid pump cooling mode, the fan speed needs to be precisely adjusted based on the temperature difference between the outlet water temperature and the ambient temperature to ensure that the natural cooling capacity matches the system requirements. Due to the lack of such differentiated control logic, the unit frequently experiences efficiency fluctuations and stability issues during variable operating conditions, such as evaporator heat exchange capacity not being maximized and mismatches in the operating parameters of key components, severely restricting the system's adaptability and reliability in complex environments. Existing technologies have not yet solved the core problem of intelligently switching operating modes based on the difference between ambient temperature and outlet water temperature setpoints, nor have they established a coordinated control system for air pump guide vanes, liquid pump speed, throttle valve opening, and fan speed, resulting in the unit being unable to achieve optimal energy efficiency across the entire operating range.

[0004] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0005] The purpose of this application is to provide a control method for a gas-refrigerant integrated magnetic levitation unit with natural cooling, which has the advantages of flexibly switching operating modes according to environmental conditions, taking into account both cooling capacity and operating energy efficiency, and improving the economic efficiency of the unit under all operating conditions.

[0006] This application provides a control method for an integrated gas-fluorine magnetic levitation unit with natural cooling, the technical solution of which is as follows:

[0007] A control method for a gas-fluorine integrated magnetic levitation unit with natural cooling includes:

[0008] The system includes a magnetic levitation air pump, an air pump outlet valve, a condenser, a liquid receiver, a first throttle valve, an evaporator, a liquid pump, a second throttle valve, a bypass valve, and a control unit.

[0009] The outlet of the magnetic levitation air pump is connected to the inlet of the air pump outlet valve, the outlet of the air pump outlet valve is connected to the inlet of the condenser, and the outlet of the condenser is connected to the inlet of the liquid receiver.

[0010] The outlet of the liquid receiver is connected to the first refrigeration branch and the second refrigeration branch, respectively.

[0011] The first refrigeration branch includes a first expansion valve and a first inlet of the evaporator connected in sequence;

[0012] The second refrigeration branch includes a liquid pump and a second throttle valve connected in sequence, with the outlet of the second throttle valve connected to the second inlet of the evaporator;

[0013] The gas outlet of the evaporator is connected to the gas pump suction line and the bypass line, respectively.

[0014] The air pump suction pipe is connected to the inlet of the magnetic levitation air pump;

[0015] The bypass line is connected to the condenser inlet via a bypass valve;

[0016] The control unit is electrically connected to the magnetic levitation air pump, the first throttle valve, the liquid pump, the second throttle valve, and the bypass valve, respectively.

[0017] The control unit is configured to selectively operate the unit in air pump cooling mode, mixed cooling mode or liquid pump cooling mode based on the difference between the ambient temperature and the set value of the outlet water temperature.

[0018] - When the difference between the ambient temperature and the outlet water temperature setting is less than or equal to the liquid pump cooling setting, the liquid pump cooling mode is activated.

[0019] - When the difference between the ambient temperature and the outlet water temperature setting is greater than or equal to the air pump cooling setting, the air pump cooling mode is activated.

[0020] - When the difference between the ambient temperature and the outlet water temperature setting is between the liquid pump cooling setting and the air pump cooling setting, the mixed cooling mode is activated.

[0021] Furthermore, this application also proposes that the control unit is configured to set a temperature deviation during unit operation to prevent frequent mode switching:

[0022] - If the current operation is in air pump cooling mode, when the difference between the ambient temperature and the outlet water temperature setting value is ≤ air pump cooling setting value - 0.5℃, switch to hybrid cooling mode;

[0023] - If currently operating in hybrid cooling mode, switch to air pump cooling mode when the difference between the ambient temperature and the outlet water temperature setting is ≥ air pump cooling setting + 0.5℃; switch to liquid pump cooling mode when the difference between the ambient temperature and the outlet water temperature setting is ≤ liquid pump cooling setting - 0.5℃.

[0024] - If the current operation is in liquid pump cooling mode, when the difference between the ambient temperature and the outlet water temperature setting value is ≥ liquid pump cooling setting value + 0.5℃, switch to hybrid cooling mode.

[0025] Furthermore, this application also proposes that the control unit is further configured to: adjust the cooling capacity by adjusting the opening degree and rotation speed of the guide vanes of the magnetic levitation air pump in air pump cooling mode or hybrid cooling mode.

[0026] Specifically, when loading is required, the opening of the guide vanes is increased first, and the rotational speed is increased after the opening of the guide vanes reaches its maximum; when unloading is required, the rotational speed is reduced first, and the opening of the guide vanes is reduced after the rotational speed reaches its minimum.

[0027] Furthermore, this application also proposes the following control logic for adjusting the cooling capacity:

[0028] i. Calculate the required load based on the deviation between the current water temperature and the set water temperature, as well as the rate of change of the water temperature;

[0029] ii. Calculate the actual load based on the opening degree of the guide vanes and the rotational speed of the magnetic levitation air pump;

[0030] iii. Compare the demand load and the actual load to determine the loading / unloading command: if the demand load is greater than the actual load, the control unit issues a loading command; if the demand load is less than the actual load, the control unit issues an unloading command.

[0031] iv. Execute adjustment actions according to loading and unloading commands: If it is a loading command, first increase the opening of the guide vanes, and then increase the speed of the magnetic levitation air pump when the opening of the guide vanes reaches its maximum; if it is an unloading command, first decrease the speed of the magnetic levitation air pump, and then decrease the opening of the guide vanes when the speed drops to its minimum; the adjustment range of the guide vane opening and the adjustment range of the magnetic levitation air pump speed are determined by the parameters set inside the magnetic levitation air pump to ensure the stable operation of the magnetic levitation air pump.

[0032] Furthermore, this application also proposes that the control unit is configured to: adjust the cooling capacity by adjusting the speed of the liquid pump in liquid pump cooling mode; increase the speed of the liquid pump if the current outlet water temperature is higher than the outlet water set value; and decrease the speed of the liquid pump if the current outlet water temperature is lower than the outlet water set value.

[0033] Furthermore, this application also proposes to include a speed-regulating fan that cooperates with the condenser, the speed-regulating fan being electrically connected to the control unit; the control unit is further configured to:

[0034] - In air pump cooling mode or hybrid cooling mode, the fan speed is controlled according to the exhaust pressure: the speed is increased when the exhaust pressure is higher than the target pressure, and the speed is decreased when the exhaust pressure is lower than the target pressure.

[0035] - In liquid pump cooling mode, the fan speed is controlled according to the difference between the outlet water temperature setpoint and the ambient temperature: the greater the difference between the outlet water temperature setpoint and the ambient temperature, the lower the fan speed; the smaller the difference, the higher the fan speed.

[0036] Furthermore, this application also proposes to include a liquid level sensor disposed on the evaporator, the liquid level sensor being electrically connected to the control unit; the control unit is further configured to:

[0037] - In hybrid refrigeration mode, the speed of the liquid pump is controlled according to the refrigerant level in the evaporator: the speed is reduced when the liquid level is higher than the target level, and the speed is increased when the liquid level is lower than the target level.

[0038] - In air pump refrigeration mode, the opening of the first throttle valve is controlled according to the refrigerant level in the evaporator: the opening is reduced when the level is higher than the target level, and the opening is increased when the level is lower than the target level.

[0039] Furthermore, this application also proposes that the control unit is further configured as follows:

[0040] - In air pump cooling mode, close the second throttle valve and bypass valve, open the first throttle valve and adjust its opening degree according to the evaporator liquid level;

[0041] - In mixed cooling mode, close the first throttle valve and bypass valve, open the second throttle valve and liquid pump, and keep the second throttle valve fully open to ensure that the refrigerant enters the evaporator as much as possible and maximizes the heat exchange capacity of the evaporator;

[0042] - In liquid pump cooling mode, turn off the magnetic levitation air pump and the first throttle valve, and open the bypass valve, liquid pump and the second throttle valve, and keep the second throttle valve fully open to ensure that the refrigerant enters the evaporator as much as possible and maximizes the heat exchange capacity of the evaporator.

[0043] Furthermore, this application also proposes that the bypass valve is an electric ball valve or an electric butterfly valve; the first throttle valve is an electronic expansion valve, an electric ball valve, or an electric butterfly valve; and the second throttle valve is an electric ball valve, an electronic expansion valve, or an electric butterfly valve.

[0044] Furthermore, this application also proposes that the liquid pump cooling setting value and the gas pump cooling setting value are preset temperature difference thresholds, and the gas pump cooling setting value is greater than the liquid pump cooling setting value.

[0045] As can be seen from the above, the control method of the gas-fluorine integrated magnetic levitation unit with natural cooling provided in this application selectively switches between three operating modes according to the difference between the ambient temperature and the set value of the outlet water temperature. It matches the most suitable refrigeration method for different temperature ranges, which solves the problem that using a single refrigeration mode alone during the transition season cannot take into account both refrigeration capacity and energy efficiency. It can achieve optimal energy efficiency in the entire operating range and has the advantages of improving the stability of unit operation and overall economy. Attached Figure Description

[0046] Figure 1 A connection diagram of an integrated air-fluorine magnetic levitation unit with natural cooling provided for this application.

[0047] Figure 2 A schematic diagram of the control logic for a gas-fluorine integrated magnetic levitation unit with natural cooling provided in this application.

[0048] Figure 3 This application provides a schematic diagram of capacity control for a magnetic levitation unit under various states.

[0049] Figure 4 This application provides a schematic diagram of the fan control for a magnetic levitation unit in various states.

[0050] Figure 5 This application provides a schematic diagram of the liquid pump control for a magnetic levitation unit under various states.

[0051] Figure 6 This application provides a schematic diagram of the throttling device control for a magnetic levitation unit under various states. Detailed Implementation

[0052] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0053] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0054] Traditional data center cooling systems consume high energy when using only air pumps for cooling during transitional seasons, and their cooling capacity is insufficient when using only liquid pumps. They lack a hybrid cooling mode to improve energy efficiency. At the same time, existing systems use a single control method in different modes and fail to differentiate and coordinate the control of air pumps, liquid pumps, throttle valves, and fans, which restricts the unit's operating efficiency and stability.

[0055] like Figure 1 As shown, this application proposes a control method for an integrated gas-refrigerant magnetic levitation chiller unit with natural cooling. This method integrates a magnetic levitation air pump 1, an air pump outlet valve 2, a condenser 3, a liquid receiver 5, a first throttle valve 6, an evaporator 7, a liquid pump 8, a second throttle valve 9, a bypass valve 10, and a control unit. The control unit selectively operates the unit in air pump cooling mode, mixed cooling mode, or liquid pump cooling mode based on the difference between the ambient temperature and the setpoint of the outlet water temperature, thereby optimizing the unit's operating efficiency.

[0056] For ease of understanding, the following explains some key terms in this embodiment:

[0057] The magnetic levitation air pump 1 is a compressor that uses magnetic levitation bearing technology. Its main function is to compress the low-temperature, low-pressure refrigerant gas that has absorbed heat in the evaporator 7 into a high-temperature, high-pressure gas, and then deliver it to the condenser 3. This technology uses magnetic force to support the rotor, avoiding mechanical friction, thereby improving operating efficiency and reliability.

[0058] When the unit is operating in liquid pump cooling mode, the magnetic levitation air pump stops working, but the liquid pump continues to drive the refrigerant circulation. At this time, if the air pump outlet valve does not have a one-way shut-off function, the high-pressure refrigerant from the condenser may flow back to the magnetic levitation air pump through the air pump outlet pipe.

[0059] The condenser 3 is a heat exchange device in the refrigeration system, used to cool and condense the high-temperature, high-pressure refrigerant gas discharged from the magnetic levitation pump 1 into a high-pressure liquid. Typically, the condenser 3 achieves the phase change of the refrigerant through heat exchange with an external cooling medium (such as air or water).

[0060] The receiver 5 is used to store the high-pressure liquid refrigerant after condensation by the condenser 3, in order to balance the fluctuations in refrigerant demand caused by changes in system load and ensure stable system operation.

[0061] The first throttling valve 6 and the second throttling valve 9 are devices used to regulate the refrigerant flow rate and reduce the refrigerant pressure. Through throttling, the high-pressure liquid refrigerant is depressurized before entering the evaporator 7, thereby achieving low-temperature evaporation and heat absorption in the evaporator 7.

[0062] Evaporator 7 is another major heat exchange device in the refrigeration system, used to absorb heat from the medium being cooled (such as chilled water) and cause the low-pressure liquid refrigerant to evaporate into a low-temperature, low-pressure gas.

[0063] The liquid pump 8 is a pump used to drive the circulation of liquid refrigerant. In natural cooling mode, the liquid pump 8 can deliver liquid refrigerant from the receiver 5 to the evaporator 7 to dissipate heat using the low outdoor temperature environment.

[0064] The bypass valve 10 is a valve used to control the flow direction of refrigerant. In this embodiment, the bypass valve 10 is used to directly bypass part of the gas discharged from the evaporator 7 to the inlet of the condenser 3 in a specific mode to regulate the system operating status.

[0065] The control unit is the core of the entire unit's control. It receives various sensor signals (such as ambient temperature, outlet water temperature, etc.) and adjusts the actuators such as the magnetic levitation air pump 1, air pump outlet valve 2, first throttle valve 6, liquid pump 8, second throttle valve 9, and bypass valve 10 according to the preset control logic to achieve efficient and stable operation of the unit in different operating modes.

[0066] The air pump cooling mode refers to the operation mode that mainly relies on the magnetic levitation air pump 1 for cooling cycle, which is suitable for situations with high ambient temperature and large cooling capacity.

[0067] Liquid pump refrigeration mode refers to an operation mode that mainly relies on liquid pump 8 to drive the refrigerant circulation and utilizes the low outdoor temperature environment for natural cooling. It is suitable for situations where the ambient temperature is low and energy-saving operation can be achieved.

[0068] Hybrid cooling mode refers to the operation mode that uses both magnetic levitation air pump 1 and liquid pump 8 for cooling cycle, which is suitable for situations where the ambient temperature is moderate and energy efficiency and cooling capacity need to be considered.

[0069] The liquid pump cooling setpoint and the gas pump cooling setpoint are preset temperature difference thresholds used to define the switching conditions for different cooling modes. These setpoints are the basis for the control unit to select the mode.

[0070] This embodiment provides a control method for an integrated gas-refrigerant magnetic levitation chiller unit with natural cooling. This method aims to improve the unit's operating efficiency under different environmental conditions through an integrated refrigeration system and control strategy. The system mainly consists of a magnetic levitation air pump 1, an air pump outlet valve 2, a condenser 3, a liquid receiver 5, a first throttling valve 6, an evaporator 7, a liquid pump 8, a second throttling valve 9, a bypass valve 10, and a control unit. The outlet of the magnetic levitation air pump 1 is connected to the inlet of the condenser 3, and the outlet of the condenser 3 is connected to the inlet of the liquid receiver 5, thus forming the main refrigerant circulation path. The outlet of the liquid receiver 5 is connected to a first refrigeration branch and a second refrigeration branch to adapt to different operating modes. The first refrigeration branch includes a first throttling valve 6 and a first inlet of the evaporator 7 connected in sequence. The second refrigeration branch includes a liquid pump 8 and a second throttling valve 9 connected in sequence, with the outlet of the second throttling valve 9 connected to the second inlet of the evaporator 7. The gas outlet of the evaporator 7 is connected to both the air pump suction line and the bypass line. The air pump suction line is connected to the inlet of the magnetic levitation air pump 1, and the bypass line is connected to the inlet of the condenser 3 via the bypass valve 10. The control unit is electrically connected to the magnetic levitation air pump 1, the first throttle valve 6, the liquid pump 8, the second throttle valve 9, and the bypass valve 10, respectively. This control unit is responsible for receiving sensor data and issuing control commands, serving as the central hub of the entire system.

[0071] like Figure 2 As shown, the control unit is configured to dynamically select the unit's operating mode based on the difference between the ambient temperature and the setpoint of the outlet water temperature. For example, the signals from the ambient temperature sensor and the outlet water temperature sensor can be periodically collected by the control unit, and the current temperature difference can be calculated. This difference reflects the actual load demand of the unit and the cooling potential of the external environment. As one implementation, the control unit can preset multiple temperature difference ranges, each corresponding to an operating mode. When the calculated difference falls within a certain range, the unit is instructed to switch to the corresponding mode. Thus, the temperature difference-based mode selection mechanism enables the unit to automatically adjust its operating strategy according to changes in the external environment, aiming to achieve energy-saving operation.

[0072] Specifically, the liquid pump cooling mode is activated when the difference between the ambient temperature and the outlet water temperature setpoint is less than or equal to the liquid pump cooling setpoint. In this mode, the unit primarily utilizes liquid pump 8 to drive refrigerant circulation, achieving natural cooling through heat exchange with the low-temperature outdoor air. For example, when the outdoor temperature is significantly lower than the outlet water temperature setpoint, the natural cooling capacity is deemed sufficient, and the liquid pump cooling mode is prioritized to reduce the operation of the magnetic levitation air pump 1, thereby lowering energy consumption.

[0073] When the difference between the ambient temperature and the outlet water temperature setpoint is greater than or equal to the air pump cooling setpoint, the air pump cooling mode is activated. In this mode, the unit primarily relies on the magnetic levitation air pump 1 for cooling circulation to meet higher cooling load demands. For example, when the outdoor temperature is high and natural cooling capacity is insufficient to meet cooling requirements, the unit switches to air pump cooling mode to ensure sufficient cooling capacity is provided.

[0074] When the difference between the ambient temperature and the outlet water temperature setpoint falls between the liquid pump cooling setpoint and the air pump cooling setpoint, the hybrid cooling mode is activated. In this mode, the unit can simultaneously utilize the magnetic levitation air pump 1 and the liquid pump 8 for cooling, balancing energy efficiency and cooling capacity. For example, during the transitional seasons of spring and autumn, when outdoor temperatures are moderate, using only the air pump for cooling may result in high energy consumption, while using only the liquid pump may lead to insufficient cooling capacity. In this case, the hybrid cooling mode can achieve a better energy efficiency ratio and cooling effect by coordinating the operation of air pump 1 and liquid pump 8.

[0075] This application effectively solves the problems of high energy consumption and insufficient cooling capacity in traditional data center cooling systems during transitional seasons by selectively operating the unit in air-pump cooling, hybrid cooling, or liquid-pump cooling modes based on the difference between the ambient temperature and the setpoint of the outlet water temperature. This method allows the unit to dynamically adjust its operating strategy according to actual load and environmental conditions. Especially during transitional seasons when outdoor ambient temperatures are moderate, the introduction of a hybrid cooling mode improves the energy efficiency ratio. As a result, the unit's operating efficiency and stability are improved, thereby reducing the overall energy consumption of the data center.

[0076] In actual operation, when the difference between the ambient temperature and the setpoint of the outlet water temperature fluctuates around the mode switching threshold, the unit may frequently switch between different cooling modes. This not only increases the burden on the control unit and reduces the stability of system operation, but may also lead to increased energy consumption and accelerated equipment wear. To address this, this application further proposes setting a temperature deviation during unit operation to prevent frequent mode switching. Setting a temperature deviation means that when switching between different cooling modes, the control unit introduces a hysteresis region or dead zone, so that the trigger condition for mode switching is no longer a single threshold, but rather different switching thresholds are used according to the current operating mode of the unit. Specifically, when the unit is currently operating in air pump cooling mode, the control unit monitors the difference between the ambient temperature and the setpoint of the outlet water temperature. Only when this difference drops to "air pump cooling setpoint - 0.5℃" or lower will the control unit instruct the unit to switch to hybrid cooling mode. This means that even if the temperature difference is slightly lower than the air pump cooling setpoint, the system will not switch immediately, but needs to drop further by 0.5℃ to trigger the switch, thus avoiding frequent switching caused by small fluctuations around the threshold.

[0077] Similarly, when the unit is currently operating in hybrid cooling mode, the control unit determines the mode based on the direction and magnitude of the temperature difference. The unit will only switch to air pump cooling mode if the difference between the ambient temperature and the outlet water temperature setpoint rises to "air pump cooling setpoint + 0.5℃" or higher; conversely, it will switch to liquid pump cooling mode if the difference drops to "liquid pump cooling setpoint - 0.5℃" or lower. This creates a 0.5℃ buffer zone between hybrid cooling mode and air pump cooling mode, as well as between hybrid cooling mode and liquid pump cooling mode, ensuring stable mode switching.

[0078] Finally, when the unit is currently operating in liquid pump cooling mode, the control unit will only instruct the unit to switch to hybrid cooling mode when the difference between the ambient temperature and the outlet water temperature setpoint rises to "liquid pump cooling setpoint + 0.5℃" or higher. This also provides a 0.5℃ lag for exiting liquid pump cooling mode, preventing frequent switching near the critical point of liquid pump cooling mode. These specific temperature deviation values ​​(e.g., 0.5℃) are preset based on actual operating experience and system characteristics, aiming to provide sufficient buffer without affecting the system's responsiveness and cooling effect.

[0079] By introducing temperature deviation during unit operation through the above technical solution, the problem of frequent switching between different cooling modes caused by fluctuations in ambient temperature or outlet water temperature setpoints is effectively solved. This hysteresis control mechanism ensures the stability of mode switching and avoids the increased burden on the control unit due to frequent processing of switching commands. Simultaneously, it reduces the number of start-ups and shutdowns of key components such as the magnetic levitation air pump 1, liquid pump 8, and various valves, as well as drastic changes in operating modes, thereby significantly reducing equipment wear and extending the unit's service life. Furthermore, the stable operating mode avoids the additional energy consumption caused by frequent switching, improving the overall operating efficiency and reliability of the refrigeration system. The unit can respond to load changes more smoothly and efficiently, providing users with a more stable cooling service.

[0080] exist Figure 3 In the further capacity control scheme shown, this application further proposes to adjust the cooling capacity by adjusting the opening degree and rotation speed of the guide vanes of the magnetic levitation air pump 1 in either the air pump cooling mode or the hybrid cooling mode. Specifically, when loading is required, the opening degree of the guide vanes is increased first, and the rotation speed is increased after the opening degree of the guide vanes reaches its maximum; when unloading is required, the rotation speed is decreased first, and the opening degree of the guide vanes is decreased after the rotation speed reaches its minimum.

[0081] The guide vane opening of the magnetic levitation air pump 1 refers to the degree of opening and closing of the guide vane assembly located at the pump inlet. By changing the opening of the guide vanes, the refrigerant flow rate and pre-swirl angle entering the pump impeller can be adjusted, thereby affecting the pump's compression efficiency and refrigerant mass flow rate, and thus achieving fine adjustment of the refrigeration capacity. Guide vane adjustment typically has a fast response speed and small energy consumption changes within a certain range, making it suitable for small-range capacity adjustment. The rotational speed of the magnetic levitation air pump 1 refers to the rotational speed of the pump impeller. Increasing the rotational speed directly increases the refrigerant compression ratio and mass flow rate, significantly improving the pump's refrigeration capacity. Rotational speed adjustment is the main means for achieving wide-range capacity adjustment in magnetic levitation air pumps, providing a larger adjustment range to adapt to large load changes.

[0082] When the system needs to increase its cooling capacity, the control unit first instructs the magnetic levitation pump 1 to increase the opening of its guide vanes. This adjustment method can quickly respond to load demands and increase cooling capacity without significantly increasing energy consumption. When the guide vane opening reaches its maximum value, meaning that the cooling capacity cannot be further increased through the guide vanes, the control unit will further instruct the magnetic levitation pump 1 to increase its speed. By increasing the speed, a wider range of cooling capacity increases can be achieved, ensuring that the unit can meet higher cooling load demands. Conversely, when the system needs to reduce its cooling capacity, the control unit first instructs the magnetic levitation pump 1 to decrease its speed. Reducing the speed is an effective way to achieve significant unloading and usually results in a significant reduction in energy consumption. When the speed decreases to its minimum operating speed, meaning that the cooling capacity cannot be further reduced through speed, the control unit will further instruct the magnetic levitation pump 1 to decrease the opening of its guide vanes. By decreasing the guide vane opening, a more precise unloading can be achieved, allowing the unit to maintain a stable operating state and high energy efficiency even when operating at low loads.

[0083] Through the above technical solutions, the unit can achieve precise, stable, and efficient adjustment of the cooling capacity of the magnetic levitation air pump 1 in either air pump cooling mode or hybrid cooling mode. By employing a loading strategy that adjusts the guide vane opening first and then the rotational speed, and an unloading strategy that adjusts the rotational speed first and then the guide vane opening, the unit can prioritize the lower energy consumption and faster response adjustment method when dealing with changes in cooling load, thereby optimizing the unit's operating efficiency and stability. This phased, coordinated adjustment method avoids the adjustment lag or over-adjustment that may result from a single adjustment method, ensuring precise control of the outlet water temperature and extending the service life of the magnetic levitation air pump 1.

[0084] In a specific implementation plan, this application further proposes a control method for an integrated gas-fluorine magnetic levitation unit with natural cooling, the control logic for adjusting the refrigeration capacity of which includes the following steps:

[0085] First, the demand load is calculated based on the deviation between the current water temperature and the set water temperature, as well as the rate of change of water temperature. Demand load refers to the cooling capacity currently required by the unit. It considers not only the static difference between the current water temperature and the user-set target water temperature but also dynamically assesses the trend of water temperature change over time. This calculation method makes the demand load assessment more forward-looking and accurate, better reflecting the system's actual cooling capacity requirements. Specifically, the control unit can use a proportional-integral-derivative (PID) control algorithm or other advanced control strategies to calculate the demand load, where the water temperature deviation serves as the input to the proportional term, and the rate of change of water temperature serves as the input to the derivative term, achieving accurate prediction and response to the load.

[0086] Secondly, the actual load is calculated based on the opening degree of the guide vanes and the rotational speed of the magnetic levitation pump 1. The actual load refers to the actual cooling capacity currently being provided by the magnetic levitation pump 1. To accurately obtain this value, the control unit can incorporate performance curve data or an empirical model of the magnetic levitation pump 1. By monitoring the opening degree of the guide vanes, rotational speed, and other relevant operating parameters (such as intake pressure and exhaust pressure) of the magnetic levitation pump 1 in real time, the control unit can accurately estimate the current actual cooling load of the unit using methods such as table lookup, interpolation, or formula calculation.

[0087] Next, the demand load and actual load are compared to determine the loading / unloading commands. The control unit continuously compares the calculated demand load with the actual load. If the demand load is greater than the actual load, it indicates that the current cooling capacity is insufficient to meet the system demand, and the control unit will issue a loading command, instructing the unit to increase the cooling capacity. Conversely, if the demand load is less than the actual load, it indicates that the current cooling capacity is excessive, and the control unit will issue an unloading command, instructing the unit to reduce the cooling capacity. To avoid the control system becoming overly sensitive and causing frequent loading / unloading actions, an appropriate hysteresis interval or dead zone can be introduced during the comparison process; that is, the loading / unloading command is only triggered when the difference between the demand load and the actual load exceeds a preset threshold.

[0088] Finally, the adjustment actions are executed according to the loading and unloading commands. If it is a loading command, the control unit will prioritize increasing the opening of the guide vanes of the magnetic levitation air pump 1. The adjustment of the guide vane opening is typically achieved through precise control of the drive motor to gradually increase the refrigerant flow into the pump. When the guide vane opening reaches its maximum value (e.g., fully open), if the system still requires further loading, the control unit will begin to increase the speed of the magnetic levitation air pump 1 by adjusting the power supply frequency via a frequency converter. If it is an unloading command, the control unit will prioritize decreasing the speed of the magnetic levitation air pump 1 by gradually decreasing the power supply frequency via a frequency converter. When the speed drops to the manufacturer-set minimum operating speed, if the system still requires further unloading, the control unit will begin to decrease the guide vane opening. During this process, the adjustment range of both the guide vane opening and the speed of the magnetic levitation air pump 1 is determined by parameters set internally within the magnetic levitation air pump 1. These parameters are preset based on the pump's operating characteristics, efficiency range, and stability requirements, aiming to ensure a smooth and efficient adjustment process, avoid unstable operating conditions such as surge, and thus guarantee the long-term reliable operation of the magnetic levitation air pump 1.

[0089] Through the above technical solution, this application provides a more refined and intelligent cooling capacity regulation control logic. This logic, by dynamically calculating the demand load and actual load, and combining this with a strategy of prioritizing the adjustment of the guide vane opening or speed, enables the unit's cooling output to precisely match the actual load demand. This not only significantly improves the unit's operating efficiency and energy saving, avoiding unnecessary energy waste, but also effectively ensures the smooth operation of the magnetic levitation air pump 1 during loading and unloading processes through preset adjustment range parameters, reducing equipment wear and extending its service life. Furthermore, considering the load calculation method based on the rate of water temperature change, the system responds more quickly and accurately to load changes, thereby maintaining stable outlet water temperature and improving the user experience.

[0090] In a further embodiment, this application proposes that, in the liquid pump cooling mode, the control unit is also configured to adjust the cooling capacity by adjusting the speed of the liquid pump 8; if the current outlet water temperature is higher than the outlet water set value, the liquid pump speed is increased; if the current outlet water temperature is lower than the outlet water set value, the liquid pump speed is decreased.

[0091] Specifically, in liquid pump cooling mode, the unit primarily utilizes the advantage of lower ambient temperatures, using liquid pump 8 to drive refrigerant circulation within the system to cool the chilled water side. This mode typically starts when the difference between the ambient temperature and the setpoint outlet water temperature is small, indicating a high potential for natural cooling, in order to reduce the energy consumption of the magnetic levitation pump 1. Adjusting the speed of liquid pump 8 is crucial for achieving precise control of cooling capacity. By changing its speed, liquid pump 8 controls the refrigerant flow rate through evaporator 7. An increase in refrigerant flow rate generally means more refrigerant participates in the evaporation and heat absorption process, thereby improving the heat exchange capacity of evaporator 7, i.e., increasing cooling capacity; conversely, a decrease in refrigerant flow rate reduces cooling capacity. This adjustment is achieved by the control unit sending a frequency converter control signal to liquid pump 8 to precisely control its output power and speed. The control unit monitors the outlet water temperature of evaporator 7 in real time and compares it with the preset outlet water temperature setpoint, thus forming a closed-loop feedback control. When the current outlet water temperature is detected to be higher than the outlet water setpoint, it indicates that the system's cooling capacity is insufficient and needs to be increased. Therefore, the control unit will issue a command to increase the speed of the liquid pump 8 to increase the refrigerant flow rate. Conversely, when the current outlet water temperature is lower than the outlet water setpoint, it indicates that the system's cooling capacity is excessive and needs to be reduced. The control unit will then issue a command to decrease the speed of the liquid pump 8 to reduce the refrigerant flow rate.

[0092] Through the above technical solution, the control unit can dynamically adjust the speed of the liquid pump 8 in liquid pump cooling mode based on the deviation between the actual outlet water temperature and the set value. This liquid pump speed adjustment mechanism based on outlet water temperature feedback allows the unit to accurately match the actual cooling load demand while utilizing the natural cooling potential. When the load increases, causing the outlet water temperature to rise, increasing the speed of the liquid pump 8 can promptly supplement the cooling capacity; when the load decreases, causing the outlet water temperature to drop, decreasing the speed of the liquid pump 8 can avoid over-cooling and save energy. This not only ensures the stability and accuracy of the outlet water temperature and improves user comfort, but also optimizes the operating efficiency of the liquid pump 8, avoiding unnecessary energy waste, thereby improving the economy and reliability of the entire unit in liquid pump cooling mode.

[0093] like Figure 1 and 4 As shown, it also includes a speed-regulating fan 4 that works in conjunction with the condenser 3. The speed-regulating fan 4 is electrically connected to the control unit, and the control unit is configured to perform differentiated control of the speed-regulating fan 4 in different operating modes.

[0094] Specifically, the variable speed fan 4 is a fan device capable of adjusting its speed according to an external control signal. Its main function is to force airflow across the heat exchange surface of the condenser 3 to enhance the heat release effect of the refrigerant in the condenser 3, thereby achieving refrigerant condensation. The variable speed fan 4 can be driven by a variable frequency motor, and the power supply frequency and voltage of the motor can be adjusted by the frequency converter to achieve stepless or multi-stage adjustment of the fan speed. It works in conjunction with the condenser 3, usually installed on the air inlet or outlet side of the condenser 3 to form effective air convection. The control unit can send control commands to the variable speed fan 4, such as speed setpoints or start / stop commands, to achieve precise control of the fan's operating status.

[0095] In air pump cooling mode or hybrid cooling mode, the control unit controls the speed of the variable-speed fan 4 based on the exhaust pressure. Specifically, the control unit continuously monitors the exhaust pressure of the magnetic levitation air pump 1. When the detected exhaust pressure is higher than the preset target pressure, it indicates that the condenser 3's heat dissipation capacity is insufficient, and the refrigerant has not condensed sufficiently. At this time, the control unit will issue a command to increase the speed of the variable-speed fan 4, increasing the airflow, thereby enhancing the heat dissipation effect of the condenser 3 and lowering the exhaust pressure. Conversely, when the exhaust pressure is lower than the target pressure, it indicates that the condenser 3's heat dissipation capacity is excessive, which may lead to a decrease in system energy efficiency. At this time, the control unit will reduce the speed of the variable-speed fan 4, reducing the airflow to maintain the exhaust pressure within the target range and save fan energy consumption. The target pressure can be a fixed value or a set value that is dynamically adjusted according to the ambient temperature or load.

[0096] In liquid pump cooling mode, the control unit controls the speed of the variable-speed fan 4 based on the difference between the outlet water temperature setpoint and the ambient temperature. Specifically, the control unit obtains the outlet water temperature setpoint and the current ambient temperature. A larger difference between the outlet water temperature setpoint and the ambient temperature indicates a lower ambient temperature and greater potential for natural cooling. In this case, even a lower fan speed can meet the heat dissipation requirements, so the control unit reduces the speed of the variable-speed fan 4 to save energy. Conversely, a smaller difference between the outlet water temperature setpoint and the ambient temperature indicates a higher ambient temperature and limited potential for natural cooling. To ensure sufficient heat dissipation, the control unit increases the speed of the variable-speed fan 4 to enhance the heat exchange capacity of the condenser 3. This control method maximizes the advantages of natural cooling while avoiding unnecessary fan energy consumption.

[0097] By introducing a speed-regulating fan 4 that works in conjunction with the condenser 3 and employing differentiated control strategies according to different operating modes, this application can significantly improve the unit's operating efficiency and stability under various working conditions. In air pump cooling mode or hybrid cooling mode, by monitoring the exhaust pressure in real time and dynamically adjusting the fan speed, the heat dissipation of the condenser 3 can be precisely controlled, maintaining the exhaust pressure within the optimal operating range. This not only avoids system overload and safety risks that may be caused by high-pressure operation, but also prevents the decrease in cooling efficiency caused by low-pressure operation, thereby ensuring the efficient and stable operation of the magnetic levitation air pump 1 and optimizing the overall cooling performance. In liquid pump cooling mode, by controlling the fan speed based on the difference between the outlet water temperature setpoint and the ambient temperature, the unit can intelligently utilize the ambient temperature for natural cooling. When the ambient temperature is low and the natural cooling potential is high, the fan speed is reduced, significantly reducing fan energy consumption; when the ambient temperature is high and the natural cooling potential is reduced, the fan speed is increased, ensuring sufficient heat dissipation capacity. This strategy allows the unit to maximize the use of free cooling sources in liquid pump cooling mode, significantly reducing operating costs and improving the overall energy efficiency ratio of the unit. In summary, this technical solution, through refined fan control, enables the unit to achieve optimal condensation performance and energy management in different cooling modes, thereby improving the unit's adaptability, reliability, and economy.

[0098] In a further embodiment, a liquid level sensor is also included, which is electrically connected to the control unit. For example... Figure 4 As shown, the control unit is also configured to: in the mixed refrigeration mode, control the speed of the liquid pump 8 according to the refrigerant level in the evaporator: reduce the speed when the liquid level is higher than the target level, and increase the speed when the liquid level is lower than the target level. Figure 5 As shown, in the air pump refrigeration mode, the opening of the first throttle valve 6 is controlled according to the refrigerant level in the evaporator: the opening is reduced when the level is higher than the target level, and the opening is increased when the level is lower than the target level.

[0099] Specifically, this level sensor is used to monitor the refrigerant level inside the evaporator 7 in real time. It can be implemented using various technologies; for example, a float-type level sensor indicates the level by the change in the position of a float; a capacitive level sensor reflects the level by measuring changes in capacitance; and an ultrasonic level sensor calculates the level by the time difference between the transmission and reception of ultrasonic waves. The level sensor transmits the detected level signal to the control unit as an input parameter for the control strategy. Its role is to provide accurate level feedback to the control unit, which is fundamental to achieving precise control of the evaporator level.

[0100] like Figure 1 and 5 As shown, in the mixed refrigeration mode, the liquid pump 8 is responsible for delivering refrigerant from the receiver 5 to the evaporator 7. The control unit receives a liquid level signal from the liquid level sensor and compares it with a preset target liquid level. When the detected liquid level is higher than the target level, it indicates that there is too much refrigerant in the evaporator 7. At this time, the control unit will issue a command to reduce the speed of the liquid pump 8, thereby reducing the refrigerant supply. Conversely, when the liquid level is lower than the target level, the control unit will increase the speed of the liquid pump 8, increasing the refrigerant supply. The speed regulation of the liquid pump 8 is usually achieved through a frequency converter to achieve smooth and precise flow control.

[0101] like Figure 1 and 6 As shown, in the air pump refrigeration mode, refrigerant enters the evaporator 7 through the first throttle valve 6. The control unit also compares the liquid level signal provided by the liquid level sensor with the target liquid level. When the refrigerant level in the evaporator 7 is higher than the target liquid level, the control unit will instruct to reduce the opening of the first throttle valve 6 to limit the refrigerant flow into the evaporator 7. When the liquid level is lower than the target liquid level, the control unit will increase the opening of the first throttle valve 6 to increase the refrigerant flow. The first throttle valve 6 is usually an electronic expansion valve, and its opening can be precisely adjusted by a stepper motor or a pulse width modulation (PWM) signal, thereby achieving fine control of the refrigerant flow.

[0102] By installing a liquid level sensor on the evaporator 7 and having the control unit adjust the speed of the liquid pump 8 or the opening of the first throttle valve 6 based on its feedback signal, this application achieves precise control of the refrigerant level within the evaporator 7. In mixed refrigeration mode, when the liquid level is higher than the target level, the control unit reduces the speed of the liquid pump 8; when the liquid level is lower than the target level, the control unit increases the speed of the liquid pump 8. This actively controls the refrigerant flow into the evaporator 7, ensuring the liquid level is maintained within the optimal range, thereby maximizing the heat exchange area and efficiency of the evaporator 7 and avoiding the risk of liquid slugging due to excessively high liquid levels or insufficient heat exchange due to excessively low liquid levels. In pneumatic refrigeration mode, when the liquid level is higher than the target level, the control unit decreases the opening of the first throttle valve 6; when the liquid level is lower than the target level, the control unit increases the opening of the first throttle valve 6. This also precisely controls the refrigerant supply, ensuring the evaporator 7 is always maintained at the optimal operating liquid level. This dynamic liquid level control mechanism significantly improves the cooling efficiency and operational stability of the unit under different operating modes, effectively avoids performance degradation and potential failures caused by liquid level fluctuations, and ensures the long-term reliable operation of the unit.

[0103] Figure 6 In the illustrated scheme, this application further proposes a method for the control unit to perform fine-grained control of various valves and components within the unit under different cooling modes. Specifically, the control unit is configured as follows:

[0104] In air pump cooling mode, the control unit commands the second throttle valve 9 and bypass valve 10 to close, while simultaneously opening the first throttle valve 6 and adjusting its opening degree according to the evaporator liquid level. In air pump cooling mode, the unit primarily relies on the magnetic levitation air pump 1 for compression refrigeration. At this time, the second refrigeration branch (including the liquid pump 8 and the second throttle valve 9) and the bypass line (including the bypass valve 10) do not participate in refrigerant throttling or bypassing. Therefore, the control unit commands the second throttle valve 9 and bypass valve 10 to close, ensuring that the refrigerant completely passes through the first refrigeration branch, i.e., the traditional compression refrigeration cycle path. This avoids refrigerant diversion or bypassing, maintains system pressure balance, and maximizes the efficiency of the air pump cooling mode. The first throttle valve 6, as the main throttling element in air pump cooling mode, is responsible for throttling and depressurizing the high-pressure liquid refrigerant and sending it into the evaporator 7. The control unit precisely adjusts the opening degree of the first throttle valve 6 according to the refrigerant liquid level in the evaporator 7 (e.g., obtained through a liquid level sensor). This adjustment aims to ensure that the refrigerant level in the evaporator 7 is maintained at an optimal level, which can prevent liquid slugging from damaging the magnetic levitation pump 1 and avoid insufficient refrigerant leading to a decrease in heat exchange efficiency, thereby maximizing the heat exchange efficiency of the evaporator 7.

[0105] In hybrid cooling mode, the control unit commands the first throttle valve 6 and bypass valve 10 to close, while simultaneously opening the second throttle valve 9 and liquid pump 8, keeping the second throttle valve 9 fully open. In hybrid cooling mode, the system may utilize both the magnetic levitation air pump 1 and liquid pump 8 for cooling, or primarily rely on liquid pump 8 to drive refrigerant circulation. Closing the first throttle valve 6 and bypass valve 10 ensures that the refrigerant primarily enters the evaporator 7 through the second cooling branch (liquid pump 8 and second throttle valve 9), avoiding unnecessary refrigerant flow and thus optimizing refrigerant distribution. Liquid pump 8 is responsible for pressurizing the liquid refrigerant in the receiver 5 and sending it to the evaporator 7. The second throttle valve 9 then throttles the pressurized refrigerant. Keeping the second throttle valve 9 fully open is designed to minimize pressure loss at the second throttle valve 9, ensuring that as much refrigerant as possible enters the evaporator 7 with low resistance. This helps to maximize the heat exchange capacity of the evaporator 7, especially in hybrid mode requiring higher cooling output, to meet the system's cooling load demands.

[0106] In liquid pump cooling mode, the control unit commands the magnetic levitation pump 1 and the first throttle valve 6 to close, while simultaneously opening the bypass valve 10, liquid pump 8, and the second throttle valve 9, keeping the second throttle valve 9 fully open. In liquid pump cooling mode, the unit relies entirely on liquid pump 8 to drive the refrigerant circulation, achieving natural cooling. Therefore, the magnetic levitation pump 1 and the first throttle valve 6 no longer participate in the refrigeration cycle; the control unit commands them to close to save energy and avoid interfering with the liquid pump cycle. Liquid pump 8 delivers refrigerant from the receiver 5 to the evaporator 7, with the second throttle valve 9 throttling the flow. The opening of the bypass valve 10 allows the gaseous refrigerant discharged from the evaporator 7 to directly bypass the inlet of the condenser 3, forming an independent liquid pump circulation loop that bypasses the magnetic levitation pump 1. This configuration achieves pure natural cooling, utilizing ambient temperature for condensation. Keep the second throttle valve 9 fully open, in the same mixed cooling mode, to ensure that the refrigerant enters the evaporator 7 as much as possible, so as to maximize the heat exchange capacity of the evaporator 7 and achieve efficient natural cooling, thereby minimizing energy consumption when environmental conditions permit.

[0107] Through the above technical solution, the control unit can intelligently adjust the working status of each valve and component according to the specific operating mode of the unit (air pump cooling mode, mixed cooling mode, or liquid pump cooling mode), thereby achieving precise control and optimization of the refrigerant flow path. In air pump cooling mode, by closing unnecessary paths and precisely adjusting the opening of the first throttle valve 6 according to the evaporator liquid level, the refrigerant is ensured to pass through the compression cycle efficiently, maximizing the cooling efficiency of the magnetic levitation air pump 1, while effectively avoiding problems such as liquid slugging or insufficient refrigerant, ensuring stable operation of the unit. In mixed cooling mode, by closing the first throttle valve 6 and the bypass valve 10, and keeping the second throttle valve 9 fully open, the refrigerant driven by the liquid pump 8 can enter the evaporator 7 to the maximum extent, thereby fully utilizing the heat exchange capacity of the evaporator 7 to achieve efficient mixed cooling and meet the cooling needs under medium load. In liquid pump refrigeration mode, by shutting down the magnetic levitation air pump 1 and the first throttle valve 6, and opening the bypass valve 10, an independent liquid pump circulation is formed, achieving pure natural cooling. Simultaneously, by fully opening the second throttle valve 9, the maximum heat exchange capacity of the evaporator 7 is ensured. Thus, when environmental conditions permit, energy consumption is minimized, significantly improving the unit's energy efficiency. This refined control strategy enables the unit to operate efficiently and stably in different operating modes, maximizing the advantages of each refrigeration mode. It effectively solves the problem of refrigerant flow path and component coordination control in different refrigeration modes, improving the overall performance and energy efficiency ratio of the unit.

[0108] The above scheme specifies the specific types of the bypass valve 10, the first throttle valve 6, and the second throttle valve 9 to ensure the accuracy and reliability of system control. Specifically, the air pump outlet valve 2 is a one-way valve, an electric ball valve, or an electric butterfly valve; the bypass valve 10 can be an electric ball valve or an electric butterfly valve; the first throttle valve 6 can be an electronic expansion valve, an electric ball valve, or an electric butterfly valve; and the second throttle valve 9 can be an electric ball valve, an electronic expansion valve, or an electric butterfly valve.

[0109] The air pump outlet valve 2 is a one-way valve, an electric ball valve, or an electric butterfly valve. When the unit is operating in liquid pump cooling mode, the magnetic levitation air pump 1 stops working, but the liquid pump 8 continues to drive the refrigerant circulation. At this time, if the air pump outlet valve 2 does not have a one-way shut-off function, the high-pressure refrigerant from the condenser 3 may flow back to the magnetic levitation air pump 1 through the air pump outlet pipe, resulting in:

[0110] The air pump rotor was forced to reverse, damaging the magnetic levitation bearing;

[0111] Liquid refrigerant accumulates inside the air pump, causing liquid slugging when it is restarted.

[0112] The air pump outlet valve 2 automatically shuts off when the air pump stops to prevent backflow.

[0113] The bypass valve 10, as a key component in the bypass pipeline, is limited to either an electric ball valve or an electric butterfly valve. The electric ball valve controls fluid flow by rotating a ball 90 degrees via an electric actuator. It features low flow resistance, good sealing performance, simple structure, and high reliability, and can achieve remote automated control. The electric butterfly valve controls fluid flow by rotating a butterfly plate via an electric actuator. It features a compact structure, light weight, low flow resistance, wide adjustment range, and fast response speed. Both types of electric valves can be electrically connected to the control unit to achieve automated control, providing a reliable actuator for unit mode switching and operation optimization, and ensuring the rapid and accurate opening or closing of the bypass path.

[0114] The first throttling valve 6 is limited to an electronic expansion valve, an electric ball valve, or an electric butterfly valve. The electronic expansion valve precisely controls the valve needle position via a stepper motor, thereby achieving continuous and precise regulation of the refrigerant flow. Its advantages include high regulation accuracy and fast response speed, enabling real-time adjustment based on system load and superheat changes, thus optimizing the heat exchange efficiency of the evaporator 7 and improving system energy efficiency. In pump-cooled or hybrid cooling modes, precise control of the refrigerant flow is crucial, and the electronic expansion valve provides this high-precision regulation capability. When an electric ball valve or electric butterfly valve is used as the first throttling valve 6, refrigerant flow control can also be achieved via an electric actuator, making it particularly suitable for applications requiring full open / full closed or limited opening adjustment, ensuring effective refrigerant throttling.

[0115] The second throttle valve 9 is limited to an electric ball valve, an electronic expansion valve, or an electric butterfly valve. Located in the second refrigeration branch, the second throttle valve 9 is primarily used to control the refrigerant flow rate in liquid pump refrigeration mode. When it is an electric ball valve or an electric butterfly valve, it can effectively open or close or regulate the refrigerant flow rate, ensuring that the refrigerant can smoothly enter the evaporator 7. When it is an electronic expansion valve, it can provide more precise flow control, further optimizing the operating efficiency in liquid pump refrigeration mode. The selection of these electric valves ensures that the control unit can precisely control the refrigerant supply according to the specific needs of liquid pump refrigeration mode.

[0116] By selecting an electric ball valve, electric butterfly valve, or electronic expansion valve as the bypass valve 10, the first throttling valve 6, and the second throttling valve 9, this application can significantly improve the accuracy and response speed of refrigerant flow control in different cooling modes. The electrical connection between the electric valves and the control unit enables the unit to achieve highly automated and intelligent operation management. For example, when the electronic expansion valve is used as the first throttling valve 6, it can adjust the refrigerant flow in real time and continuously according to the actual load and superheat of the evaporator 7, thereby maximizing the heat exchange efficiency of the evaporator 7, avoiding refrigerant return or insufficient liquid supply, and improving the energy efficiency ratio in both gas pump cooling mode and mixed cooling mode. Simultaneously, the electric ball valve or electric butterfly valve, as the bypass valve 10, can quickly and reliably switch the bypass path, ensuring that the refrigerant can efficiently pass through the bypass pipeline in liquid pump cooling mode, avoiding unnecessary energy loss. The precise control capabilities of these valves effectively solve the problems of mode switching fluctuations and decreased cooling efficiency caused by inaccurate valve adjustment or slow response. This enables the unit to switch and operate smoothly and efficiently between gas pump cooling mode, mixed cooling mode and liquid pump cooling mode, thereby improving the overall operational stability, reliability and energy efficiency of the unit.

[0117] In the above scheme, the liquid pump cooling setpoint and the air pump cooling setpoint are preset temperature difference thresholds, and the air pump cooling setpoint is greater than the liquid pump cooling setpoint. Specifically, the liquid pump cooling setpoint is a preset temperature difference threshold, which defines the conditions for the unit to start the liquid pump cooling mode. When the difference between the ambient temperature and the outlet water temperature setpoint is less than or equal to this threshold, the control unit will instruct the system to start the liquid pump cooling mode. The setting of this threshold should comprehensively consider the economy and applicability of the liquid pump cooling mode, ensuring that the energy-saving advantages of the liquid pump can be fully utilized when the ambient temperature is relatively low and the cooling load is small. The air pump cooling setpoint is also a preset temperature difference threshold, used to define the conditions for the unit to start the air pump cooling mode. When the difference between the ambient temperature and the outlet water temperature setpoint is greater than or equal to this threshold, the control unit will instruct the system to start the air pump cooling mode. The setting of this threshold should ensure that when the ambient temperature is high and the cooling load is large, the magnetic levitation air pump 1 can intervene in time to provide sufficient cooling capacity. Furthermore, this application clarifies that the setpoint for air pump cooling is greater than that for liquid pump cooling. This setting defines the logical relationship between the two key thresholds: the activation conditions for air pump cooling mode are more stringent than those for liquid pump cooling mode (requiring a larger temperature difference). This relationship ensures that the three cooling modes (liquid pump cooling mode, hybrid cooling mode, and air pump cooling mode) have clear, non-overlapping intervals on the temperature difference axis. For example, the setpoint for liquid pump cooling can be set to 5℃, and the setpoint for air pump cooling to 10℃. Then, when the temperature difference is ≤5℃, it is liquid pump cooling; when the temperature difference is ≥10℃, it is air pump cooling; and when 5℃ < temperature difference < 10℃, it is hybrid cooling.

[0118] By clearly defining the liquid pump cooling setpoint and the gas pump cooling setpoint as preset temperature difference thresholds, and further limiting the gas pump cooling setpoint to be greater than the liquid pump cooling setpoint, this application provides a clearer and more stable mode switching logic. This explicit threshold definition and their hierarchical relationship eliminate ambiguity in mode judgment, ensuring that the control unit can accurately and unambiguously select the most suitable operating mode under different ambient temperature and outlet water temperature setpoint differences. For example, when the difference between the ambient temperature and the outlet water temperature setpoint is between the liquid pump cooling setpoint and the gas pump cooling setpoint, the system will stably operate in a mixed cooling mode, avoiding frequent mode oscillations caused by unclear threshold definitions. This not only improves the reliability and stability of unit operation but also helps optimize energy efficiency, as the system can always select the most energy-efficient cooling method based on actual operating conditions.

[0119] The following example will provide a more detailed explanation of the above technical solution:

[0120] In a data center, users need to maintain a stable temperature in the server room year-round and minimize cooling energy consumption. This data center is equipped with a combined gas-cooled and refrigerant-cooled magnetic levitation chiller unit. Its control unit selects the operating mode based on the difference between the ambient temperature and the setpoint of the outlet water temperature. Assume the liquid pump cooling setpoint is 5°C and the gas pump cooling setpoint is 15°C.

[0121] The refrigerant circulation system of the unit includes a magnetic levitation pump 1, a condenser 3, a liquid receiver 5, a first throttle valve 6, an evaporator 7, a liquid pump 8, a second throttle valve 9, a bypass valve 10, and a control unit. The outlet of the magnetic levitation pump 1 is connected to the inlet of the condenser 3, and the outlet of the condenser 3 is connected to the inlet of the liquid receiver 5. The outlet of the liquid receiver 5 is connected to both a first refrigeration branch and a second refrigeration branch. The first refrigeration branch includes the first throttle valve 6 and the first inlet of the evaporator 7 connected in sequence. The second refrigeration branch includes the liquid pump 8 and the second throttle valve 9 connected in sequence, with the outlet of the second throttle valve 9 connected to the second inlet of the evaporator 7. The gas outlet of the evaporator 7 is connected to both the pump suction line and the bypass line. The pump suction line is connected to the inlet of the magnetic levitation pump 1. The bypass line is connected to the inlet of the condenser 3 via the bypass valve 10. The control unit is electrically connected to the magnetic levitation pump 1, the first throttle valve 6, the liquid pump 8, the second throttle valve 9, and the bypass valve 10.

[0122] Scenario 1: Low-temperature environment in winter (liquid pump cooling mode)

[0123] Assuming it's winter and the outdoor ambient temperature is 0℃, the data center's outlet water temperature is set to 15℃. At this time, the difference between the ambient temperature and the outlet water temperature setting is 0℃ - 15℃ = -15℃. Since -15℃ is less than or equal to the liquid pump cooling setting of -11℃, the control unit activates the liquid pump cooling mode.

[0124] In this mode, the control unit shuts down the magnetic levitation air pump 1 and the first throttle valve 6, and opens the bypass valve 10, the liquid pump 8, and the second throttle valve 9. The second throttle valve 9 remains fully open to ensure that refrigerant enters the evaporator 7 as much as possible, maximizing the heat exchange capacity of the evaporator 7. The liquid pump 8 drives the refrigerant to circulate in the system, utilizing the low-temperature outdoor air to dissipate heat through the condenser 3, achieving natural cooling.

[0125] To accurately adjust the cooling capacity, the control unit adjusts the speed of the liquid pump 8 based on the deviation between the current outlet water temperature and the set outlet water temperature. For example, if the current outlet water temperature is 16°C, which is higher than the set value of 15°C, the control unit will increase the speed of the liquid pump 8 to increase the refrigerant flow rate, thereby enhancing the cooling capacity. If the outlet water temperature drops to 14°C, which is lower than the set value, the speed of the liquid pump 8 will be reduced.

[0126] Simultaneously, the unit is also equipped with a speed-regulating fan 4 that works in conjunction with the condenser 3. In liquid pump cooling mode, the control unit controls the speed of fan 4 based on the difference (15°C) between the outlet water temperature setpoint of 15°C and the ambient temperature of 0°C. The larger the difference, the lower the fan speed; the smaller the difference, the higher the fan speed. For example, when the ambient temperature further decreases and the difference increases, the fan speed will be appropriately reduced to optimize energy consumption. This precise control avoids the energy efficiency losses caused by simple start-stop or single parameter adjustment in existing technologies.

[0127] Scenario 2: High-temperature environment in summer (air pump cooling mode)

[0128] Assuming it's summer and the outdoor ambient temperature is 30℃, the data center's outlet water temperature is set to 15℃. The difference between the ambient temperature and the outlet water temperature setting is 30℃ - 15℃ = 15℃. Since 15℃ is greater than or equal to the air pump cooling setting of 5℃, the control unit activates the air pump cooling mode.

[0129] In this mode, the control unit closes the second throttle valve 9 and the bypass valve 10, and opens the first throttle valve 6. The magnetic levitation air pump 1 starts running, compressing the refrigerant that has absorbed heat in the evaporator 7, increasing its pressure and temperature, and sending it to the condenser 3 for heat dissipation.

[0130] To adjust the cooling capacity, the control unit regulates the opening and rotational speed of the guide vanes of the magnetic levitation air pump 1. Specifically, the control unit calculates the required load based on the deviation between the current water temperature and the set water temperature, as well as the rate of change of the water temperature, and compares this calculation with the actual load calculated using the opening and rotational speed of the guide vanes of the magnetic levitation air pump 1. If the required load is greater than the actual load, the control unit issues a loading command, first increasing the opening of the guide vanes; when the opening of the guide vanes reaches its maximum, the rotational speed of the magnetic levitation air pump 1 is then increased. If the required load is less than the actual load, an unloading command is issued, first decreasing the rotational speed of the magnetic levitation air pump 1; when the rotational speed reaches its minimum, the opening of the guide vanes is then decreased. This tiered adjustment strategy ensures stable and efficient operation of the magnetic levitation air pump 1, which is superior to the simple control of a single adjustment parameter in existing technologies.

[0131] A liquid level sensor is installed on the evaporator 7 and is electrically connected to the control unit. In the air pump cooling mode, the control unit controls the opening of the first throttle valve 6 based on the refrigerant level in the evaporator 7. If the liquid level is higher than the target level, the opening is reduced to prevent liquid backflow; if the liquid level is lower than the target level, the opening is increased to ensure sufficient heat exchange. This avoids the liquid backflow or overheating problems caused by improper throttle valve opening in the prior art.

[0132] Meanwhile, in the air pump cooling mode, the speed control fan 4 controls the speed according to the exhaust pressure: when the exhaust pressure is higher than the target pressure, the speed is increased, and when it is lower than the target pressure, the speed is decreased, so as to maintain the stability of the condensing pressure and optimize the system efficiency.

[0133] Scenario 3: Spring and Autumn Transition Season (Hybrid Cooling Mode)

[0134] Assuming it's during the transitional spring / autumn season, the outdoor ambient temperature is 15℃, and the data center's outlet water temperature is set to 15℃. At this time, the difference between the ambient temperature and the outlet water temperature setting is 15℃ - 15℃ = 0℃. Since 0℃ falls between the liquid pump cooling setting of -11℃ and the air pump cooling setting of 5℃, the control unit activates the hybrid cooling mode.

[0135] In this mode, the control unit closes the first throttle valve 6 and the bypass valve 10, and opens the second throttle valve 9 and the liquid pump 8. The second throttle valve 9 remains fully open to ensure that refrigerant enters the evaporator 7 as much as possible, maximizing the heat exchange capacity of the evaporator 7. The magnetic levitation pump 1 also operates simultaneously. At this time, the unit utilizes both the natural cooling driven by the liquid pump 8 and the mechanical cooling of the magnetic levitation pump 1, working in synergy to effectively solve the problems of high energy consumption or insufficient cooling capacity in existing technologies during transitional seasons, resulting in a significant improvement in the energy efficiency ratio.

[0136] In hybrid cooling mode, the control unit also adjusts the cooling capacity by regulating the opening and rotation speed of the guide vanes of the magnetic levitation air pump 1, following the same logic as in air pump cooling mode. Furthermore, in this mode, the liquid level sensor on the evaporator 7 controls the rotation speed of the liquid pump 8 based on the refrigerant level within the evaporator 7: the speed decreases when the liquid level is higher than the target level and increases when it is lower than the target level, ensuring the intake superheat of the magnetic levitation air pump 1 and maintaining stable system operation. This is a sophisticated coordinated control strategy lacking in existing technologies.

[0137] In the mixed cooling mode, the speed control fan 4 also controls its speed according to the exhaust pressure, just like in the air pump cooling mode.

[0138] Stability control of mode switching

[0139] To prevent frequent unit switching due to ambient temperature fluctuations during transitional seasons, the control unit is set with a temperature deviation. For example:

[0140] If the system is currently operating in air pump cooling mode, the control unit will switch to hybrid cooling mode when the difference between the ambient temperature and the set outlet water temperature drops from 15℃ to 4.5℃ (i.e., 5℃ - 0.5℃).

[0141] If the system is currently operating in hybrid cooling mode, it will switch to air pump cooling mode only when the temperature difference rises from 0℃ to 5.5℃ (i.e., 5℃ + 0.5℃); and it will switch to liquid pump cooling mode only when the temperature difference drops from 0℃ to -11.5℃ (i.e., -11℃ - 0.5℃).

[0142] If the system is currently operating in liquid pump cooling mode, it will switch to hybrid cooling mode only when the temperature difference increases from -15℃ to -10.5℃ (i.e., -11℃ + 0.5℃).

[0143] This mode switching mechanism with delay features effectively avoids the large number of switching operations caused by simple threshold judgment in existing technologies, thus improving the stability and reliability of unit operation.

[0144] As can be seen from the above example, the control method of this integrated gas-fluorine magnetic levitation unit with natural cooling solves the problems of high energy consumption, insufficient cooling capacity, and limited operating efficiency and stability in existing technologies during transitional seasons, as well as the limitations of simple control strategies, by selecting three operating modes: gas pump cooling, mixed cooling, or liquid pump cooling, and then performing differentiated and coordinated control of the magnetic levitation gas pump 1, liquid pump 8, throttling valves (first throttling valve 6, second throttling valve 9), and speed-regulating fan 4 in different modes. The various technical features work closely together to form a highly efficient and stable overall solution.

[0145] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A control method for a gas-fluorine integrated magnetic levitation unit with natural cooling, characterized in that, include: The system includes a magnetic levitation air pump (1), an air pump outlet valve (2), a condenser (3), a liquid receiver (5), a first throttle valve (6), an evaporator (7), a liquid pump (8), a second throttle valve (9), a bypass valve (10), and a control unit. The outlet of the magnetic levitation air pump (1) is connected to the inlet of the air pump outlet valve (2), the outlet of the air pump outlet valve (2) is connected to the inlet of the condenser (3), and the outlet of the condenser (3) is connected to the inlet of the liquid reservoir (5). The outlet of the liquid receiver (5) is connected to the first refrigeration branch and the second refrigeration branch respectively; The first refrigeration branch includes the first throttle valve (6) and the first inlet of the evaporator (7) connected in sequence; The second refrigeration branch includes the liquid pump (8) and the second throttle valve (9) connected in sequence, and the outlet of the second throttle valve (9) is connected to the second inlet of the evaporator (7); The gas outlet of the evaporator (7) is connected to the gas pump suction line and the bypass line, respectively; The air pump suction pipe is connected to the inlet of the magnetic levitation air pump (1); The bypass line is connected to the inlet of the condenser (3) via the bypass valve (10); The control unit is electrically connected to the magnetic levitation air pump (1), the air pump outlet valve (2), the first throttle valve (6), the liquid pump (8), the second throttle valve (9), and the bypass valve (10), respectively. The control unit is configured to selectively operate the unit in air pump cooling mode, mixed cooling mode or liquid pump cooling mode based on the difference between the ambient temperature and the set value of the outlet water temperature. - When the difference between the ambient temperature and the outlet water temperature set value is less than or equal to the liquid pump cooling set value, the liquid pump cooling mode is activated; - When the difference between the ambient temperature and the outlet water temperature setting is greater than or equal to the air pump cooling setting, the air pump cooling mode is activated. - When the difference between the ambient temperature and the outlet water temperature setting is between the liquid pump cooling setting and the air pump cooling setting, the hybrid cooling mode is activated.

2. The control method for the gas-fluorine integrated magnetic levitation unit with natural cooling according to claim 1, characterized in that, The control unit is also configured to set a temperature deviation during unit operation to prevent frequent mode switching. - If the current operation is in air pump cooling mode, when the difference between the ambient temperature and the outlet water temperature setting value is ≤ air pump cooling setting value - 0.5℃, switch to hybrid cooling mode; - If the current operation is in hybrid cooling mode, when the difference between the ambient temperature and the outlet water temperature setting value is ≥ the air pump cooling setting value + 0.5℃, switch to air pump cooling mode; when the difference between the ambient temperature and the outlet water temperature setting value is ≤ the liquid pump cooling setting value - 0.5℃, switch to liquid pump cooling mode. - If the current operation is in liquid pump cooling mode, when the difference between the ambient temperature and the outlet water temperature setting value is ≥ liquid pump cooling setting value + 0.5℃, switch to hybrid cooling mode.

3. The control method for the gas-fluorine integrated magnetic levitation unit with natural cooling according to claim 1, characterized in that, The control unit is also configured to: adjust the cooling capacity by adjusting the opening degree and rotation speed of the guide vanes of the magnetic levitation air pump (1) in the air pump cooling mode or the hybrid cooling mode; Specifically, when loading is required, the opening of the guide vanes is increased first, and the rotational speed is increased after the opening of the guide vanes reaches its maximum; when unloading is required, the rotational speed is reduced first, and the opening of the guide vanes is reduced after the rotational speed reaches its minimum.

4. The control method for the gas-fluorine integrated magnetic levitation unit with natural cooling according to claim 3, characterized in that, The control logic for adjusting the cooling capacity is as follows: i. Calculate the required load based on the deviation between the current water temperature and the set water temperature, as well as the rate of change of the water temperature; ii. Calculate the actual load based on the opening degree of the guide vanes and the rotational speed of the magnetic levitation air pump; iii. Compare the demand load and the actual load to determine the loading / unloading command: if the demand load is greater than the actual load, the control unit issues a loading command; if the demand load is less than the actual load, the control unit issues an unloading command. iv. Execute adjustment actions according to loading and unloading commands: If it is a loading command, first increase the opening of the guide vanes, and then increase the speed of the magnetic levitation air pump when the opening of the guide vanes reaches its maximum; if it is an unloading command, first decrease the speed of the magnetic levitation air pump, and then decrease the opening of the guide vanes when the speed drops to its minimum; the adjustment range of the guide vane opening and the adjustment range of the magnetic levitation air pump speed are determined by the parameters set inside the magnetic levitation air pump to ensure the stable operation of the magnetic levitation air pump.

5. The control method for the gas-fluorine integrated magnetic levitation unit with natural cooling according to claim 1, characterized in that, The control unit is also configured to: adjust the cooling capacity by adjusting the speed of the liquid pump (8) in the liquid pump cooling mode; increase the speed of the liquid pump if the current outlet water temperature is higher than the outlet water set value; and decrease the speed of the liquid pump if the current outlet water temperature is lower than the outlet water set value.

6. The control method for the gas-fluorine integrated magnetic levitation unit with natural cooling according to claim 1, characterized in that, It also includes a speed-regulating fan (4) that cooperates with the condenser (3), the speed-regulating fan (4) being electrically connected to the control unit; the control unit is further configured to: - In the air pump cooling mode or the hybrid cooling mode, the fan speed is controlled according to the exhaust pressure: the speed is increased when the exhaust pressure is higher than the target pressure, and the speed is decreased when the exhaust pressure is lower than the target pressure. - In the liquid pump cooling mode, the fan speed is controlled according to the difference between the outlet water temperature setpoint and the ambient temperature: the greater the difference between the outlet water temperature setpoint and the ambient temperature, the lower the fan speed; the smaller the difference, the higher the fan speed.

7. The control method for the gas-fluorine integrated magnetic levitation unit with natural cooling according to claim 1, characterized in that, It also includes a liquid level sensor disposed on the evaporator (7), the liquid level sensor being electrically connected to the control unit; the control unit is further configured to: - In the mixed refrigeration mode, the speed of the liquid pump (8) is controlled according to the refrigerant level in the evaporator: the speed is reduced when the liquid level is higher than the target liquid level, and the speed is increased when the liquid level is lower than the target liquid level; - In the air pump refrigeration mode, the opening degree of the first throttle valve (6) is controlled according to the refrigerant level in the evaporator: the opening degree is reduced when the liquid level is higher than the target liquid level, and the opening degree is increased when the liquid level is lower than the target liquid level.

8. The control method for the gas-fluorine integrated magnetic levitation unit with natural cooling according to claim 1, characterized in that, The control unit is also configured to: - In the air pump refrigeration mode, close the second throttle valve (9) and the bypass valve (10), open the first throttle valve (6) and adjust its opening degree according to the evaporator liquid level; - In the mixed refrigeration mode, the first throttle valve (6) and the bypass valve (10) are closed, the second throttle valve (9) and the liquid pump (8) are opened, and the second throttle valve (9) is kept fully open to ensure that the refrigerant enters the evaporator as much as possible and to maximize the heat exchange capacity of the evaporator; - In the liquid pump refrigeration mode, the magnetic levitation air pump (1) and the first throttle valve (6) are turned off, the bypass valve (10), the liquid pump (8) and the second throttle valve (9) are turned on, and the second throttle valve (9) is kept fully open to ensure that the refrigerant enters the evaporator as much as possible and exerts the maximum heat exchange capacity of the evaporator.

9. The control method for the gas-fluorine integrated magnetic levitation unit with natural cooling according to claim 1, characterized in that, The air pump outlet valve (2) is a check valve, an electric ball valve, or an electric butterfly valve; the bypass valve (10) is an electric ball valve or an electric butterfly valve; the first throttle valve (6) is an electronic expansion valve, an electric ball valve, or an electric butterfly valve; the second throttle valve (9) is an electric ball valve, an electronic expansion valve, or an electric butterfly valve.

10. The control method for the gas-fluorine integrated magnetic levitation unit with natural cooling according to claim 1, characterized in that, The liquid pump cooling setting value and the gas pump cooling setting value are preset temperature difference thresholds, and the gas pump cooling setting value is greater than the liquid pump cooling setting value.

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