Cold plate type two-phase liquid cooling system and phase change CDU and phase change cabinet thereof

Abstract

The invention discloses a cold plate type two-phase liquid cooling system and a phase change CDU and a phase change cabinet thereof. The phase change CDU comprises a primary side loop, a secondary side loop, a heat exchanger, a fluorine pump, a dryness regulator, a subcooler, a subcooling degree regulator, a subcooling degree detection assembly and a first controller. And the first controller adjusts the fluorine pump and the dryness adjuster according to the return air dryness, and adjusts the supercooling degree adjuster according to the outlet supercooling degree, so that the return air is ensured to be in a gas-liquid two-phase state, and the outlet is in a liquid state. The phase change cabinet comprises an inlet pipeline, an outlet pipeline, a plurality of server cold plates connected in parallel and a flow control assembly arranged at the downstream of the liquid collector, and the flow control assembly comprises a pressure sensor, a temperature sensor, a throttle valve and a second controller and is used for controlling the dryness of an outlet refrigerant; one phase change CDU is connected with a plurality of phase change cabinets in parallel. The problems of insufficient liquid supply supercooling degree, uneven cabinet shunting, local overheating and system oscillation caused by traditional pressure difference control are solved, and the stability, uniformity and expandability of the system are improved.

Description

Technical Field

[0001] This application relates to the field of temperature control for data centers, specifically to a cold plate type two-phase liquid cooling system and its phase change CDU and phase change cabinet. Background Technology

[0002] With the increasing demand for heat dissipation in data centers, liquid cooling technology has gradually become one of the mainstream solutions due to its efficient heat dissipation capabilities. Among them, cold plate liquid cooling systems are widely used in high-density data centers due to their advantages such as compact structure, flexible deployment, and good compatibility with servers. Traditional cold plate liquid cooling systems typically use deionized water as the cooling medium, utilizing the contact between the cold plate and the heat-generating components of the server for heat transfer, and then using a CDU (Coolant Distribution Unit) to achieve heat exchange and circulation.

[0003] However, traditional water-cooling systems have a significant safety hazard: the coolant is based on deionized water, which, although treated, still retains some conductivity. If the coolant leaks inside the server, it could lead to short circuits, equipment burnout, or even flooding of the server room. To mitigate this risk, the industry has gradually shifted to using refrigerants with better insulation properties instead of water as the cooling medium, resulting in the cold-plate two-phase liquid cooling system. This system utilizes the latent heat of phase change of the refrigerant to achieve efficient heat exchange, offering higher heat transfer efficiency and better electrical safety.

[0004] Currently, cold-plate two-phase liquid cooling systems mainly consist of two core components: a cold-plate phase-change cooling unit (hereinafter referred to as phase-change CDU), which is responsible for providing power for the secondary refrigerant circulation and performing heat exchange; and a cold-plate phase-change cabinet (hereinafter referred to as phase-change cabinet), which is used to house the servers and distribute refrigerant for cooling. However, existing technologies have the following shortcomings: (1) Existing phase change CDUs typically use the control logic of traditional liquid cooling systems, with the pressure difference between the inlet and outlet of the refrigerant pump as the control target. This method performs well in single-phase liquid cooling systems, but in two-phase liquid cooling systems, due to the gas-liquid phase change of the refrigerant during circulation, it is difficult to ensure the thermodynamic stability of the refrigerant by simply relying on pressure difference control. Under certain special operating conditions, it may lead to insufficient subcooling of the liquid supply, causing the refrigerant to be in a gas-liquid mixed state when entering the cabinet, which in turn leads to problems such as uneven distribution within the cabinet, local overheating of the server, and system oscillation.

[0005] (2) Existing phase change cabinets mostly use the traditional liquid-cooled cabinet structure, which mainly relies on a purely mechanical manifold for refrigerant distribution. When the refrigerant entering the cabinet is in a gas-liquid two-phase state, due to the large difference in the density of the gas and liquid fluids, the mechanical manifold is difficult to achieve uniform distribution, which can easily lead to insufficient flow to some servers and local overheating. Although some patents have proposed adding valves and other flow control devices to each server branch to refine the control granularity, this method will significantly increase the system complexity, occupy a large amount of cabinet space, and the control logic is complex. Summary of the Invention

[0006] This application provides a cold plate type two-phase liquid cooling system, its phase change CDU and phase change cabinet, which can solve the problem that the control method of traditional liquid cooling system in the prior art is not completely applicable to phase change liquid cooling system, resulting in insufficient liquid supply subcooling. This leads to a gas-liquid mixture when the refrigerant enters the phase change cabinet, resulting in uneven distribution within the cabinet, causing local overheating of the server and system oscillation.

[0007] In a first aspect, embodiments of this application provide a phase-change CDU, which includes: The primary side circuit is used to connect to the cold source; The secondary side loop is used to connect to the phase change cabinet and to exchange heat with the primary side loop through a heat exchanger; a dryness detection component is installed on the pipeline between the secondary side inlet and the refrigerant inlet of the heat exchanger; a refrigerant pump, a dryness regulator, a subcooler, a subcooling regulator, and a subcooling detection component are sequentially installed on the pipeline between the refrigerant outlet of the heat exchanger and the secondary side outlet. A first controller is configured to adjust the subcooling regulator based on the outlet subcooling detected by the subcooling detection component, and to adjust the dryness regulator and the refrigerant pump based on the return gas dryness detected by the dryness detection component.

[0008] Preferably, the dryness detection component includes a first temperature detector and a first pressure detector connected in series; The supercooling detection component includes a second temperature detector and a second pressure detector connected in series.

[0009] Preferably, the dryness regulator includes a first throttle valve, the inlet of which is connected to the pipeline connecting the refrigerant pump and the subcooler, and the outlet is connected to the pipeline where the secondary side inlet is located, and is located downstream of the dryness detection component.

[0010] Preferably, the subcooling regulator includes a second throttle valve, the inlet of which is connected to the pipe connecting the subcooler and the subcooling detection component, and the outlet is connected to the pipe where the secondary side inlet is located, and is located between the dryness detection component and the target connection point; the target connection point is the connection point between the first throttle valve and the pipe where the secondary side inlet is located.

[0011] Preferably, when the detected return gas dryness is less than the first dryness set threshold, the first controller preferentially reduces the frequency of the fluorine pump. If the frequency of the fluorine pump drops to the lowest level, the first throttle valve is opened and the opening degree of the first throttle valve is controlled. When the detected return gas dryness is greater than the second dryness set threshold, the first controller first reduces the opening of the first throttle valve. If the opening of the first throttle valve is closed to the minimum, the frequency of the refrigerant pump is increased. When the detected return gas dryness is between the first dryness setting threshold and the second dryness setting threshold, it indicates that the detected return gas dryness is within the normal range, and the first controller controls the refrigerant pump and the first throttle valve to maintain the current state; the second dryness setting threshold is greater than the first dryness setting threshold.

[0012] Preferably, when the detected outlet subcooling degree is greater than the first subcooling degree threshold, the first controller controls the opening degree of the second throttle valve to decrease; When the detected outlet subcooling is less than the second subcooling threshold, the first controller controls the opening of the second throttle valve to increase. When the detected outlet subcooling is between the second subcooling threshold and the first subcooling threshold, the first controller controls the second throttle valve to maintain its current state; the first subcooling threshold is greater than the second subcooling threshold.

[0013] Preferably, a first regulating valve is provided in the primary side circuit, located at the cold source outlet of the heat exchanger; When the refrigerant temperature at the secondary outlet is greater than the first temperature threshold, the first controller controls the opening of the first regulating valve to increase. When the refrigerant temperature at the secondary outlet is less than the second temperature threshold, the first controller controls the opening of the first regulating valve to decrease; the first temperature threshold is greater than the second temperature threshold. When the refrigerant temperature at the secondary outlet is greater than the third subcooling threshold and less than the fourth subcooling threshold, the first controller controls the first regulating valve to maintain its current opening; the fourth subcooling threshold is greater than the third subcooling threshold.

[0014] Secondly, a phase-change cabinet is provided, comprising: The inlet piping is used to connect to the phase change CDU. Outlet pipeline; Multiple server cold plates are connected in parallel, with the inlet end connected to the inlet pipeline via a liquid separator and the outlet end connected to the outlet pipeline via a liquid collector. A flow control assembly is disposed on the outlet pipe and located downstream of the liquid collector; the flow control assembly includes a third pressure detector, a third temperature detector and a third throttle valve arranged sequentially along the refrigerant flow direction, and a second controller; the second controller is used to control the opening degree of the third throttle valve according to the detection values ​​of the third pressure detector and the third temperature detector.

[0015] Preferably, the second controller is used to determine the refrigerant dryness at the computer cabinet outlet based on the detection values ​​of the third pressure detector and the third temperature detector; When the refrigerant dryness at the cabinet outlet is greater than the third dryness setting threshold, the second controller controls the opening of the third throttle valve to increase. When the refrigerant dryness at the cabinet outlet is less than the fourth dryness setting threshold, the second controller controls the opening of the third throttle valve to decrease. When the refrigerant dryness at the cabinet outlet is between the fourth dryness setting threshold and the third dryness setting threshold, the second controller controls the opening of the third throttle valve to maintain the current state; the third dryness setting threshold is greater than the fourth dryness setting threshold.

[0016] Thirdly, a cold plate type two-phase liquid cooling system is provided, which includes: Phase transition CDU; Phase change cabinet; The first annular pipe loop is connected to the secondary side outlet of the secondary side loop of the phase change CDU, and the inlet pipes of multiple phase change cabinets are connected in parallel with the first annular pipe loop. The second annular pipe loop is connected to the secondary side inlet of the secondary side loop of the phase change CDU, and the outlet pipes of multiple phase change cabinets are connected in parallel with the second annular pipe loop.

[0017] The beneficial effects of the technical solutions provided in this application include: Firstly, to address the issue of insufficient subcooling in the refrigerant supply, a subcooler, a subcooling detection component, and a subcooling regulator are sequentially installed between the refrigerant outlet and the secondary side outlet of the heat exchanger. The subcooling detection component monitors the temperature and pressure of the outlet refrigerant in real time. The first controller calculates the actual subcooling based on the detected values ​​and compares it with a set threshold, dynamically adjusting the opening of the subcooling regulator. When insufficient subcooling is detected, the controller increases the regulator opening, increasing the bypass refrigerant flow rate, enhancing the cooling effect of the subcooler, and ensuring that the outlet refrigerant has sufficient subcooling, fundamentally preventing the refrigerant from entering the cabinet in a gas-liquid mixed state.

[0018] Secondly, addressing the issue of uneven refrigerant distribution in the cabinet and localized server overheating caused by the gas-liquid mixture, the system ensures that the outlet refrigerant is a single-phase liquid. This allows for even distribution to each server's cold plates by the distributor after entering the cabinet, avoiding the uneven distribution caused by density differences in the gas-liquid two-phase flow and thus eliminating the risk of localized server overheating. Finally, regarding system oscillation, the first controller monitors the return gas dryness and outlet subcooling in real time, coordinating the adjustment of the refrigerant pump frequency and multiple regulating valves to form a closed-loop control. This control logic can quickly respond to load changes, maintaining the system under stable operating conditions and avoiding the oscillations caused by traditional differential pressure control under varying conditions. In summary, this system fundamentally solves the technical problems of unstable refrigerant supply, uneven cabinet refrigerant distribution, and system oscillation. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the phase change CDU structure of this application; Figure 2 This is a schematic diagram of the phase change cabinet form of this application; Figure 3 This is a schematic diagram of Form 2 of the phase change cabinet in this application; Figure 4 This is a schematic diagram of the cold plate type two-phase liquid cooling system of this application.

[0020] In the diagram: 1. Heat exchanger; 2. Fluorine pump; 3. Subcooler; 4. First controller; 5. First temperature detector; 6. First pressure detector; 7. Second temperature detector; 8. Second pressure detector; 9. First throttle valve; 10. Second throttle valve; 11. First regulating valve; 12. Inlet pipe; 13. Outlet pipe; 14. Server cold plate; 15. Third throttle valve; 16. Second controller; 17. First annular loop; 18. Second annular loop. Detailed Implementation

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

[0022] First, some of the technical terms used in this application will be explained to help those skilled in the art understand this application.

[0023] In cold-plate liquid cooling systems, the coolant is primarily deionized water, which has high conductivity. The coolant is directly channeled into the cold plates inside the server to remove heat. During operation, coolant leakage can lead to serious operational problems such as server burnout and data center flooding. Replacing water with a refrigerant in cold-plate liquid cooling systems effectively mitigates this risk, leading to the development of a cold-plate two-phase liquid cooling system solution.

[0024] Currently, the main components of a cold plate type two-phase liquid cooling system are a cold plate type phase change CDU (hereinafter referred to as phase change CDU) and a cold plate type phase change cabinet (hereinafter referred to as phase change cabinet).

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0026] Firstly, reference Figure 1 This application provides a phase change CDU, which includes: The primary side circuit is used to connect to the cold source; The secondary side loop is used to connect to the phase change cabinet and is connected to the primary side loop for heat exchange through heat exchanger 1; wherein, a dryness detection component is installed on the pipeline between the secondary side inlet and the refrigerant inlet of heat exchanger 1; a refrigerant pump 2, a dryness regulator, a subcooler 3, a subcooling regulator, and a subcooling detection component are sequentially installed on the pipeline between the refrigerant outlet of heat exchanger 1 and the secondary side outlet. The first controller 4 is used to adjust the subcooling regulator based on the outlet subcooling detected by the subcooling detection component, and to adjust the dryness regulator and the refrigerant pump 2 based on the return gas dryness detected by the dryness detection component.

[0027] By integrating the primary side loop, secondary side loop, heat exchanger 1, refrigerant pump 2, dryness regulator, subcooler 3, subcooling regulator, subcooling detection component, and first controller 4, an intelligent temperature control unit with closed-loop control capability is constructed. Its core effect lies in achieving precise regulation of the secondary side refrigerant state, ensuring stable system operation under different load conditions. Specifically, the dryness detection component monitors the dryness of the return gas refrigerant in real time. Based on this signal, the first controller coordinates the refrigerant pump frequency and the dryness regulator to ensure that the return gas refrigerant is always in a gas-liquid two-phase state, avoiding system oscillation or decreased heat exchange efficiency due to overheating or excessive dryness. Simultaneously, the subcooling detection component monitors the subcooling of the outlet refrigerant in real time. The first controller controls the bypass refrigerant flow by adjusting the subcooling regulator to ensure sufficient subcooling of the outlet refrigerant, preventing a gas-liquid two-phase state when it enters the cabinet, thereby ensuring the uniform distribution capability of the distributor within the cabinet. This design not only improves the system's response speed and control accuracy but also enhances its robustness under varying operating conditions, avoiding the limitations of traditional differential pressure control methods in phase change liquid cooling systems, such as insufficient subcooling and gas-liquid mixing. Furthermore, the introduction of the first controller enables the system to adaptively adjust, reducing the need for manual intervention and improving the system's intelligence and operational reliability. In summary, this phase change CDU demonstrates significant technical effectiveness in improving system stability, ensuring equipment safety, and optimizing energy efficiency.

[0028] In some preferred embodiments, the dryness detection component includes a first temperature detector 5 and a first pressure detector 6 connected in series; The subcooling detection component includes a second temperature detector 7 and a second pressure detector 8 connected in series.

[0029] This implementation achieves precise sensing of the refrigerant's thermodynamic state by incorporating temperature and pressure sensors connected in series in the dryness and subcooling detection components, respectively. First, the combined detection of temperature and pressure accurately calculates key parameters such as dryness, subcooling, or superheat of the refrigerant at specific locations, providing a reliable input signal to the primary controller and avoiding misjudgments or control deviations caused by environmental interference or inherent accuracy limitations of a single sensor. Second, this detection method, based on the thermophysical properties of the refrigerant, accurately reflects the phase changes of the refrigerant, ensuring that the control system's judgment of the system state has a physical basis, thereby improving the scientific rigor and accuracy of the control. Furthermore, this design is simple in structure, easy to integrate, and does not occupy additional space, making it suitable for high-density deployments in data center environments. In addition, by monitoring the temperature and pressure of key nodes in real time, the system can promptly detect abnormal states such as overheating, undercooling, and two-phase inhomogeneity, triggering corresponding adjustment mechanisms to provide fault warning and protection, laying a solid foundation for the stable operation of the entire phase change liquid cooling system.

[0030] In some preferred embodiments, the dryness regulator includes a first throttle valve 9, the inlet of which is connected to a pipe connecting the refrigerant pump 2 and the subcooler 3, and the outlet is connected to the pipe where the secondary side inlet is located, and is located downstream of the dryness detection component.

[0031] In this embodiment, a bypass circuit for adjusting the dryness of the return gas is constructed by setting a first throttle valve 9 between the fluorine pump 2 and the subcooler 3 and connecting its outlet back to the secondary side inlet pipeline.

[0032] First, this structure allows the first controller 4 to adjust the bypass flow rate to change the outlet pressure of the refrigerant pump 2 without interrupting the main circuit flow, thereby affecting the dryness of the return gas refrigerant and achieving flexible regulation of the return gas state. Second, when the return gas dryness is detected to be too low, the system can first reduce the frequency of the refrigerant pump 2. If this still cannot meet the requirements, the first throttle valve is gradually opened to increase the bypass flow rate and reduce the outlet pressure of the refrigerant pump, causing the refrigerant to maintain a gas-liquid two-phase state on the return gas side. Conversely, when the return gas dryness is too high, the system can close the throttle valve to reduce the bypass, improve the efficiency of the refrigerant pump, and avoid overheating. This graded regulation mechanism not only improves the smoothness and stability of regulation but also avoids system oscillations caused by over-regulation of a single actuator. In addition, the bypass circuit design is compact, responsive, and does not introduce additional power equipment, reducing system complexity and cost. More importantly, this design ensures that the return gas refrigerant is always in an ideal two-phase state, avoiding a decrease in heat exchange efficiency or unstable operation of the refrigerant pump due to abnormal dryness, thereby improving the energy efficiency and reliability of the entire system.

[0033] In some preferred embodiments, the subcooling regulator includes a second throttle valve 10, the inlet of which is connected to the pipe connecting the subcooler 3 and the subcooling detection component, and the outlet is connected to the pipe where the secondary side inlet is located, and is located between the dryness detection component and the target connection point; the target connection point is the connection point between the first throttle valve 9 and the pipe where the secondary side inlet is located.

[0034] In this embodiment, a low-temperature bypass loop for adjusting the subcooling of the outlet refrigerant is constructed by setting a second throttle valve 10 after the subcooler 3 and connecting its outlet back to the secondary side inlet pipe.

[0035] First, this loop utilizes the principle of throttling, pressure reduction, and temperature reduction. A small amount of refrigerant from the main circuit is throttled and converted into low-temperature, low-pressure refrigerant, which then exchanges heat with the main circuit refrigerant through a subcooler, achieving secondary cooling and effectively increasing the subcooling degree of the outlet refrigerant. Second, the first controller monitors the subcooling degree of the outlet refrigerant in real time and adjusts the opening of the second throttling valve according to a set threshold, achieving precise control of the subcooling degree. When the subcooling is too low, the valve opening is increased to increase the bypass flow and enhance the cooling effect; when the subcooling is too high, the valve opening is decreased to reduce the cooling intensity. This closed-loop regulation mechanism ensures that the outlet refrigerant always has sufficient subcooling, preventing a gas-liquid two-phase state when it enters the cabinet, thus ensuring the uniformity of the liquid distribution in the cabinet's distributor and preventing server malfunctions due to localized overheating. Furthermore, this design is compact, does not occupy additional space, and is suitable for high-density deployment scenarios; the control logic is simple and reliable, with a fast response speed, adapting to subcooling requirements under different load conditions. More importantly, the design of this loop avoids the drawbacks of relying on external cold sources or complex heat exchange equipment in traditional methods, reducing system costs and energy consumption.

[0036] In some preferred embodiments, when the detected return gas dryness is less than the first dryness setting threshold, the first controller 4 preferentially reduces the frequency of the refrigerant pump 2. If the frequency of the refrigerant pump 2 drops to the minimum, the first throttle valve 9 is opened and the opening degree of the first throttle valve 9 is controlled. The first dryness setting threshold = return gas dryness setting value - blind zone value one. When the detected return gas dryness is greater than the second dryness setting threshold, the first controller 4 preferentially reduces the opening of the first throttle valve 9. If the opening of the first throttle valve 9 is closed to the minimum, the frequency of the refrigerant pump 2 is increased. The second dryness setting threshold = return gas dryness setting value + blind zone value one. When the detected return gas dryness is between the first dryness setting threshold and the second dryness setting threshold, it indicates that the detected return gas dryness is within the normal range, and the first controller 4 controls the refrigerant pump 2 and the first throttle valve 9 to maintain the current state; the second dryness setting threshold is greater than the first dryness setting threshold.

[0037] This embodiment presents a hierarchical control logic based on a return gas dryness threshold, executed by a first controller. It prioritizes adjusting the refrigerant pump frequency, then adjusts the opening of the first throttle valve. The technical advantages are as follows: First, prioritizing the adjustment of the refrigerant pump frequency allows for rapid response to system changes. As the refrigerant pump is the power source, its frequency changes directly affect refrigerant flow and pressure, thus quickly altering the return gas dryness and avoiding system oscillations that might be caused by frequent valve adjustments. Second, when the refrigerant pump frequency, even at its lowest setting, still cannot meet the dryness requirement, the system gradually opens the first throttle valve to increase the bypass flow and further adjust the return gas state. Conversely, when the dryness is too high, the throttle valve is closed first; if this still fails, the refrigerant pump frequency is increased. This hierarchical adjustment strategy not only ensures the smoothness and stability of the adjustment but also avoids over-adjustment of a single actuator, extending equipment lifespan. Furthermore, setting a blind zone value—the range between the first and second dryness thresholds—prevents frequent adjustments due to minor fluctuations, improving system operational stability and control efficiency. In addition, this control logic, based on real-time detection data, can adapt to changes in dryness under different operating conditions, ensuring that the return gas refrigerant is always in an ideal gas-liquid two-phase state, thus avoiding a decrease in heat exchange efficiency or system oscillation caused by abnormal dryness.

[0038] In some preferred embodiments, when the detected outlet subcooling is greater than the first subcooling threshold, the first controller 4 controls the opening of the second throttle valve 10 to decrease; the first subcooling threshold = subcooling set value + blind zone value 2; When the detected outlet subcooling is less than the second subcooling threshold, the first controller 4 controls the opening of the second throttle valve 10 to increase; the second subcooling threshold = subcooling set value - blind zone value two; When the detected outlet subcooling is between the second subcooling threshold and the first subcooling threshold, the first controller 4 controls the second throttle valve 10 to maintain the current state; the first subcooling threshold is greater than the second subcooling threshold.

[0039] This embodiment proposes a control logic based on a threshold value for outlet subcooling, executed by a first controller. Precise control of subcooling is achieved by adjusting the opening of a second throttle valve. The technical effects are as follows: First, when excessive outlet subcooling is detected, the controller reduces the opening of the second throttle valve, decreasing the bypass refrigerant flow and reducing cooling intensity to prevent energy efficiency degradation or insufficient refrigerant flow due to excessive subcooling. Conversely, when subcooling is insufficient, the controller increases the valve opening, increasing the bypass flow and enhancing the cooling effect to ensure sufficient subcooling of the outlet refrigerant. This closed-loop regulation mechanism ensures that the outlet refrigerant is always in an ideal subcooled state, preventing a two-phase gas-liquid state when it enters the cabinet, thus ensuring the uniformity of the liquid distribution in the cabinet's distributor and preventing server malfunctions due to localized overheating. Second, setting a blind zone value—the range between the second and first subcooling thresholds—prevents frequent valve operation due to minor fluctuations, improving system stability and valve lifespan. Furthermore, this control logic, based on real-time detection data, can adapt to the subcooling requirements under different load conditions, with fast response speed and high control accuracy, avoiding system oscillation or equipment damage caused by insufficient subcooling in traditional methods.

[0040] In some preferred embodiments, a first regulating valve 11 is provided in the primary side circuit and at the cold source outlet of heat exchanger 1; When the refrigerant temperature at the secondary outlet is greater than the first temperature threshold, the first controller 4 controls the opening of the first regulating valve 11 to increase; the first temperature threshold = temperature setpoint + blind zone value 3; When the refrigerant temperature at the secondary outlet is less than the second temperature threshold, the first controller 4 controls the opening of the first regulating valve 11 to decrease; the first temperature threshold is greater than the second temperature threshold; the second temperature threshold = temperature setpoint - blind zone value 3; When the refrigerant temperature at the secondary outlet is greater than the third subcooling threshold and less than the fourth subcooling threshold, the first controller 4 controls the first regulating valve 11 to maintain its current opening. The fourth subcooling threshold is greater than the third subcooling threshold. The third subcooling threshold = subcooling setpoint - blind zone value three; the fourth subcooling threshold = subcooling setpoint + blind zone value three. A control logic based on the refrigerant temperature at the secondary side outlet is proposed. This logic is executed by a first controller, which dynamically adjusts the flow rate on the cold source side by regulating the opening of the first regulating valve in the primary side loop. The technical advantages are as follows: First, when the refrigerant temperature at the secondary side outlet is too high, the controller opens the first regulating valve wider, increasing the flow rate on the cold source side and enhancing the heat exchanger's heat exchange capacity, thereby reducing the secondary side outlet temperature. Conversely, when the temperature is too low, the controller closes the first regulating valve, reducing the flow rate on the cold source side, decreasing the heat exchange intensity, and preventing overcooling. This regulation mechanism achieves coordinated control between the cold source side and the load side, ensuring that the secondary side outlet temperature remains within the ideal range and avoiding system efficiency degradation or equipment damage due to abnormal temperatures. Second, setting a blind zone value, i.e., the range between the third and fourth subcooling thresholds, prevents frequent adjustments due to small temperature fluctuations, improving system stability and valve lifespan. Furthermore, this control logic, based on real-time detection data, can adapt to different environmental conditions and load changes, exhibiting fast response speed and high control accuracy, avoiding system oscillations caused by lag in cold source side regulation in traditional methods. More importantly, this design improves heat exchange efficiency and reduces energy consumption by optimizing the flow distribution on the cold source side, which aligns with the development trend of green data centers.

[0041] Secondly, a phase-change cabinet is provided, comprising: Inlet pipe 12 is used to connect to the phase change CDU; Outlet pipe 13; Multiple server cold plates 14 are connected in parallel, with the inlet end connected to the inlet pipe 12 via a liquid separator and the outlet end connected to the outlet pipe 13 via a liquid collector. A flow control assembly is installed on the outlet pipe 13 and located downstream of the liquid collector. The flow control assembly includes a third pressure detector, a third temperature detector, and a third throttle valve 15 arranged sequentially along the refrigerant flow direction, as well as a second controller 16. The second controller 16 is used to control the opening degree of the third throttle valve 15 according to the detection values ​​of the third pressure detector and the third temperature detector.

[0042] By installing a flow control component downstream of the liquid collector, including a pressure sensor, a temperature sensor, and a throttle valve, and combining it with a second controller, precise control of the refrigerant dryness at the cabinet outlet is achieved.

[0043] First, the flow control component is located downstream of the liquid collector, avoiding interference from the throttling valve on the upstream distributor. This ensures the refrigerant maintains a stable flow state before entering the distributor, guaranteeing uniform flow distribution across all server cold plates and preventing localized overheating due to uneven flow. Second, through a combination of third pressure and third temperature sensors, the second controller can detect the refrigerant dryness at the computer cabinet outlet in real time and adjust the opening of the third throttling valve according to a set threshold. This ensures the outlet refrigerant is always in a gas-liquid two-phase state, preventing heat exchange efficiency reduction or system oscillation caused by overheating or excessive dryness. Third, this design is compact and easily integrated into existing liquid-cooled cabinets without occupying additional space, making it suitable for high-density server deployments. Furthermore, the second controller operates independently without data interaction with the CDU controller, reducing system complexity and deployment difficulty, and improving system modularity and scalability. More importantly, this design, through real-time monitoring and closed-loop regulation, can promptly detect and correct abnormal states, providing fault warning and protection, thus enhancing system safety and reliability.

[0044] In some preferred embodiments, the second controller 16 is used to determine the refrigerant dryness at the computer cabinet outlet based on the detection values ​​of the third pressure detector and the third temperature detector; When the refrigerant dryness at the cabinet outlet is greater than the third dryness setting threshold, the second controller 16 controls the opening of the third throttle valve 15 to increase; the third dryness setting threshold = setting value + blind zone value three; When the refrigerant dryness at the cabinet outlet is less than the fourth dryness setting threshold, the second controller 16 controls the opening of the third throttle valve 15 to decrease; the fourth dryness setting threshold = setting value - blind zone value three; When the refrigerant dryness at the cabinet outlet is between the fourth dryness setting threshold and the third dryness setting threshold, the second controller 16 controls the opening of the third throttle valve 15 to maintain the current state; the third dryness setting threshold is greater than the fourth dryness setting threshold.

[0045] This control logic, based on real-time monitoring data, adapts to changes in refrigerant dryness under varying load conditions, exhibiting fast response and high control precision. It avoids the uneven flow distribution problems inherent in traditional mechanical components under gas-liquid two-phase flow. More importantly, this design ensures that each server's cold plate receives the appropriate amount of refrigerant through precise adjustment, preventing localized overheating and controlling the refrigerant dryness at the rack outlet. The dryness range is 0.3–0.7, representing a gas-liquid two-phase state, preventing refrigerant overheating. This improves server operational stability and lifespan. The third throttling valve 15 has a throttling effect on the refrigerant and therefore cannot be placed at the rack inlet to avoid uneven flow distribution from the distributor. The cross-sectional dimension of the liquid collector, i.e., the section perpendicular to the flow direction, should be 1.4 times or more the size of the distributor. The rack outlet can discharge liquid upwards or downwards, as per reference. Figure 2 and Figure 3 ; Thirdly, refer to Figure 4 A cold plate type two-phase liquid cooling system is provided, which includes: The above phase transition CDU; Multiple or more phase change cabinets; The first annular pipe loop 17 is connected to the secondary side outlet of the secondary side loop of the phase change CDU, and the inlet pipes 12 of multiple phase change cabinets are connected in parallel with the first annular pipe loop 17. The second ring-shaped pipe loop 18 is connected to the secondary side inlet of the secondary side loop of the phase change CDU, and the outlet pipes 13 of multiple phase change cabinets are connected in parallel with the second ring-shaped pipe loop 18.

[0046] A flexible and scalable liquid cooling system was constructed by connecting the phase change CDU and multiple phase change cabinets in parallel through a ring network.

[0047] Its technical advantages are reflected in the following aspects: First, the design of the first ring-shaped pipe loop and the first ring-shaped pipe loop achieves uniform distribution and return of refrigerant, avoiding the impact of a single point of failure on the whole system and improving the redundancy and reliability of the system. Second, each phase change CDU and each phase change cabinet is equipped with an independent controller, and their operation does not interfere with each other, reducing the system coupling and improving deployment flexibility and scalability—users can flexibly increase or decrease the number of cabinets according to actual needs without modifying the control logic or re-debugging the system.

[0048] Furthermore, the ring network design reduces pipeline pressure drop and flow resistance, improves refrigerant flow efficiency, and lowers refrigerant pump energy consumption, aligning with the trend of green energy conservation. In addition, the system supports decoupled control between the CDU and the racks, enabling seamless integration of equipment from different manufacturers, enhancing system compatibility and market potential. More importantly, the modular architecture simplifies on-site installation and maintenance processes, reducing operation and maintenance costs and troubleshooting difficulty. In actual operation, the system can adapt to different load conditions and environmental changes, ensuring that servers in each rack are always in optimal cooling condition, avoiding performance degradation or equipment damage caused by localized overheating.

[0049] It should be understood in this application that: Existing phase change cooling units (CDUs) typically use differential pressure control methods from traditional single-phase liquid cooling systems, which cannot detect the dryness of the return gas refrigerant. In two-phase liquid cooling systems, the dryness of the return gas refrigerant directly affects the operating efficiency of the refrigerant pump and the overall energy efficiency of the system. If the return gas refrigerant is overheated, it will lead to an increase in the refrigerant pump's suction specific volume, a decrease in flow rate, and an increase in power consumption; if the return gas refrigerant is over-humidified, it may cause liquid slugging in the refrigerant pump and damage to the equipment. This application monitors the dryness of the return gas refrigerant in real time by setting up a dryness detection component, and coordinates the refrigerant pump frequency and dryness regulator with the first controller to ensure that the return gas refrigerant is always in a gas-liquid two-phase state, avoiding overheating or over-humidification. This design not only improves the operating efficiency and lifespan of the refrigerant pump, but also optimizes the overall energy efficiency of the system and reduces operating costs. At the same time, by controlling the return gas dryness within an ideal range, system oscillations caused by abnormal dryness are avoided, improving the system's operational stability.

[0050] In two-phase liquid cooling systems, if the refrigerant entering the cabinet is in a gas-liquid two-phase state, the large density difference between the two phases makes it difficult for traditional mechanical distributors to achieve uniform distribution, easily leading to insufficient flow to some servers and localized overheating. While some existing technologies have proposed adding branch valves to refine the control granularity, this method significantly increases system complexity, occupies a large amount of cabinet space, and has complex control logic, making its practical application extremely rare. This application addresses this issue by incorporating a subcooler, subcooling detection component, and subcooling regulator within the CDU, and introducing a first controller for closed-loop control of subcooling. This ensures that the outlet refrigerant has sufficient subcooling, maintaining a single-phase liquid state when entering the cabinet. This design fundamentally avoids the problem of gas-liquid two-phase flow entering the cabinet, guarantees the uniform flow distribution capability of the distributor within the cabinet, and thus solves the problem of localized server overheating caused by uneven flow distribution. Furthermore, it eliminates the need for additional control components within the cabinet, resulting in a compact structure and simple control.

[0051] Data center loads exhibit significant volatility and uncertainty, requiring liquid cooling systems to possess strong adaptive adjustment capabilities. Existing phase change CDU control methods suffer from slow response speeds and low adjustment accuracy, making it difficult to adapt to rapidly changing load demands and prone to system oscillations or energy efficiency degradation. This application introduces a first controller and dynamically adjusts the refrigerant pump, dryness regulator, and subcooling regulator based on real-time detected dryness and subcooling data, achieving adaptive closed-loop control of the system. This design can quickly respond to load changes, ensuring stable operation of the system under various operating conditions and improving system robustness and reliability. Simultaneously, by setting a control blind zone, frequent adjustments caused by minor fluctuations are avoided, improving system operational stability and equipment lifespan.

[0052] This application incorporates a first regulating valve in the primary side loop, and a first controller adjusts its opening based on the refrigerant temperature at the secondary side outlet, thereby dynamically regulating the flow rate on the cold source side. When the secondary side outlet temperature is too high, the first regulating valve opens wider, increasing the flow rate on the cold source side and enhancing heat exchange capacity; conversely, when the temperature is too low, the first regulating valve closes less, reducing the flow rate on the cold source side and decreasing the heat exchange intensity. This design achieves coordinated control between the cold source side and the load side, ensuring that the secondary side outlet temperature remains within the ideal range, thus preventing system energy efficiency degradation or equipment damage due to abnormal temperatures. Simultaneously, by optimizing the cold source side flow distribution, heat exchange efficiency is improved, energy consumption is reduced, aligning with the development trend of green data centers.

[0053] This application integrates the dryness detection component, subcooling detection component, and primary controller within the CDU, achieving centralized control of the secondary refrigerant status. This eliminates the need for complex control devices on the cabinet side, simplifying the system structure and reducing deployment difficulty and maintenance costs. Furthermore, this design supports decoupled control between the CDU and the cabinet, enabling seamless integration of equipment from different manufacturers, thus enhancing system compatibility and market potential. In practical applications, users can flexibly expand the number of cabinets according to actual needs without modifying the control logic or re-tuning the system, improving deployment flexibility and scalability.

[0054] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0055] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0056] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0057] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0058] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0059] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0060] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A phase-change CDU, characterized in that, It includes: The primary side circuit is used to connect to the cold source; The secondary side loop is used to connect with the phase change cabinet and is connected to the primary side loop for heat exchange through the heat exchanger (1); wherein, a dryness detection component is provided on the pipeline between the secondary side inlet and the refrigerant inlet of the heat exchanger (1); a fluorine pump (2), a dryness regulator, a subcooler (3), a subcooling regulator, and a subcooling detection component are sequentially provided on the pipeline between the refrigerant outlet of the heat exchanger (1) and the secondary side outlet; The first controller (4) is used to adjust the subcooling regulator according to the outlet subcooling detected by the subcooling detection component, and to adjust the dryness regulator and the refrigerant pump (2) according to the return gas dryness detected by the dryness detection component.

2. The phase change CDU as described in claim 1, characterized in that: The dryness detection component includes a first temperature detector (5) and a first pressure detector (6) connected in series. The supercooling detection component includes a second temperature detector (7) and a second pressure detector (8) connected in series.

3. The phase change CDU as described in claim 2, characterized in that: The dryness regulator includes a first throttle valve (9), the inlet of which is connected to the pipeline connecting the fluorine pump (2) and the subcooler (3), and the outlet is connected to the pipeline where the secondary side inlet is located, and is located downstream of the dryness detection component.

4. The phase change CDU as described in claim 3, characterized in that: The subcooling regulator includes a second throttle valve (10). The inlet of the second throttle valve (10) is connected to the pipeline connecting the subcooler (3) and the subcooling detection component, and the outlet is connected to the pipeline where the secondary side inlet is located, and is located between the dryness detection component and the target connection point. The target connection point is the connection point between the first throttle valve (9) and the pipeline where the secondary side inlet is located.

5. The phase change CDU as described in claim 3, characterized in that: When the detected return gas dryness is less than the first dryness set threshold, the first controller (4) preferentially reduces the frequency of the fluorine pump (2). If the frequency of the fluorine pump (2) drops to the lowest level, the first throttle valve (9) is opened and the opening degree of the first throttle valve (9) is controlled. When the detected return gas dryness is greater than the second dryness setting threshold, the first controller (4) preferentially reduces the opening of the first throttle valve (9). If the opening of the first throttle valve (9) is closed to the minimum, the frequency of the fluorine pump (2) is increased. When the detected return gas dryness is between the first dryness setting threshold and the second dryness setting threshold, it indicates that the detected return gas dryness is within the normal range. The first controller (4) controls the fluorine pump (2) and the first throttle valve (9) to maintain the current state. The second dryness setting threshold is greater than the first dryness setting threshold.

6. The phase change CDU as described in claim 4, characterized in that: When the detected outlet subcooling is greater than the first subcooling threshold, the first controller (4) controls the opening of the second throttle valve (10) to decrease; When the detected outlet subcooling is less than the second subcooling threshold, the first controller (4) controls the opening of the second throttle valve (10) to increase; When the detected outlet subcooling is between the second subcooling threshold and the first subcooling threshold, the first controller (4) controls the second throttle valve (10) to maintain the current state; the first subcooling threshold is greater than the second subcooling threshold.

7. The phase change CDU as described in claim 3, characterized in that: In the primary circuit, a first regulating valve (11) is provided at the cold source outlet of the heat exchanger (1). When the refrigerant temperature at the secondary outlet is greater than the first temperature threshold, the first controller (4) controls the opening of the first regulating valve (11) to increase; When the refrigerant temperature at the secondary outlet is less than the second temperature threshold, the first controller (4) controls the opening of the first regulating valve (11) to decrease; the first temperature threshold is greater than the second temperature threshold. When the refrigerant temperature at the secondary outlet is greater than the third subcooling threshold and less than the fourth subcooling threshold, the first controller (4) controls the first regulating valve (11) to maintain the current opening; the fourth subcooling threshold is greater than the third subcooling threshold.

8. A phase change cabinet, characterized in that, It includes: Inlet pipe (12), which is used to connect to the phase change CDU; Outlet pipeline (13); Multiple server cold plates (14) are connected in parallel, and the liquid inlet is connected to the inlet pipe (12) through a liquid separator, and the liquid outlet is connected to the outlet pipe (13) through a liquid collector. A flow control assembly is provided on the outlet pipe (13) and located downstream of the liquid collector; the flow control assembly includes a third pressure detector, a third temperature detector and a third throttle valve (15) arranged sequentially along the refrigerant flow direction, and a second controller (16); the second controller (16) is used to control the opening degree of the third throttle valve (15) according to the detection values ​​of the third pressure detector and the third temperature detector.

9. The phase change cabinet as described in claim 8, characterized in that: The second controller (16) is used to determine the refrigerant dryness at the computer cabinet outlet based on the detection values ​​of the third pressure detector and the third temperature detector. When the refrigerant dryness at the cabinet outlet is greater than the third dryness setting threshold, the second controller (16) controls the opening of the third throttle valve (15) to increase; When the refrigerant dryness at the cabinet outlet is less than the fourth dryness setting threshold, the second controller (16) controls the opening of the third throttle valve (15) to decrease; When the refrigerant dryness at the cabinet outlet is between the fourth dryness setting threshold and the third dryness setting threshold, the second controller (16) controls the opening of the third throttle valve (15) to maintain the current state; the third dryness setting threshold is greater than the fourth dryness setting threshold.

10. A cold plate type two-phase liquid cooling system, characterized in that, It includes: Phase transition CDU as described in any one of claims 1-7; Multiple phase change cabinets as described in any one of claims 8-9; The first annular pipe loop (17) is connected to the secondary side outlet of the secondary side loop of the phase change CDU, and the inlet pipes (12) of multiple phase change cabinets are connected in parallel with the first annular pipe loop (17). The second annular pipe loop (18) is connected to the secondary side inlet of the secondary side loop of the phase change CDU, and the outlet pipes (13) of multiple phase change cabinets are connected in parallel with the second annular pipe loop (18).

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