Air cooler and cooling method for a CO2 critical system

Abstract

The application relates to the technical field of heat exchange equipment, and particularly provides a heat exchange device CO 2Air cooler and cooling method of critical system. The air cooler comprises a tube bundle assembly, a tube box assembly, a fan system, a control unit and a lightweight framework. The tube bundle assembly adopts micro-channel flat tubes or internal thread tubes to improve heat transfer efficiency; the tube box assembly integrates a filtering module and a pre-stabilization chamber to ensure reliable sealing; the fan system optimizes air distribution through combination of axial flow and centrifugal fans; and the control unit dynamically controls operation parameters based on sensor data. The cooling method comprises CO 2Fluid pretreatment, heat exchange matching and critical parameter optimization. The application solves the problems of low heat transfer efficiency and unreliable sealing of traditional technology, and compared with the prior art, actually measured heat exchange efficiency is improved, and the application is suitable for supercritical CO 2Energy system.

Description

Technical Field

[0001] This invention relates to the field of heat exchange equipment technology, specifically to equipment suitable for... CO 2. Supercritical or near-critical operating conditions (critical temperature 31.1℃, critical pressure 7.38℃) MPa Air coolers and their cooling methods. Background Technology

[0002] exist CO 2. In refrigeration, heat pump and energy cycle systems, CO 2. Critical systems are widely used due to their environmental friendliness and excellent thermodynamic performance. Their matching air coolers are used to achieve the desired cooling effect inside the tubes. CO 2. Core equipment for heat exchange between fluid and external air. Existing... CO 2. Air coolers for critical systems often use bare tubes as heat transfer elements, paired with a single axial fan to provide cooling airflow. The sealing structure is made of ordinary carbon steel or rubber. The control logic is based only on simple temperature feedback to adjust the fan speed, and there is a lack of targeted dust cleaning design.

[0003] However, existing air coolers in CO 2. Significant defects exist under critical operating conditions: 1. Low heat transfer efficiency: The boundary layer on the inner wall of the tube is thick. CO 2. The fluid flow path is short, and there is no enhanced heat transfer structure, so the heat transfer coefficient is only... 1. Difficult to meet the high heat transfer requirements under critical conditions; 2. Unreliable sealing: Ordinary carbon steel / rubber sealing materials are not resistant to supercritical conditions. CO 2. Corrosion, at 7.38 CO The above-mentioned high-pressure conditions are prone to aging and leakage, with a leakage rate of up to 0.5% / year, posing a safety hazard; 3. Poor heat exchange uniformity: A single axial flow fan cannot regulate local airflow, easily leading to uneven flow distribution in the tube bundle area, with local heat exchange temperature differences reaching 5-8℃, resulting in unstable system operation; 4. High energy consumption and maintenance costs: The fan lacks a frequency converter design, operating at full load even under low load conditions, resulting in high energy consumption (…). MPa The heat exchange efficiency is only 1.0-1.2, and there is no automatic cleaning function after the fins accumulate dust. The heat exchange efficiency decreases by 20% every month, requiring frequent manual maintenance and significantly increasing costs. Summary of the Invention

[0004] This invention aims to solve the existing COP 2. Air coolers used in critical systems suffer from low heat transfer efficiency, poor heat exchange uniformity, high energy consumption, and high maintenance costs after dust accumulation. Furthermore, they lack the technical expertise to precisely control critical operating conditions.

[0005] To address the aforementioned technical problems, the present invention provides the following technical solution.

[0006] A sort of CO2 Air cooler for critical system, comprising a tube bundle assembly, a tube box assembly, a fan system, a control unit and a lightweight framework, a sensor group; the lightweight framework is fixed with the ground foundation through the anchor bolt, and provides an installation platform and a protection space for other assemblies; the tube bundle assembly is arranged inside the lightweight framework, and both ends are fixedly connected with the tube box assembly through bolts; the fan system is installed on the side of the tube box assembly, is fixedly welded with the lightweight framework through a fan support, and an air outlet is aligned with the heat transfer pipe of the tube bundle assembly to form an air circulation channel; the control unit is integrated on one side of the lightweight framework, and signal and control connection is established between the control unit, the fan system and the sensor group through waterproof and dustproof line pipes.

[0007] In the preferred embodiment of the present application, a filter module is sequentially connected behind the inlet pipe of the tube box assembly; the filter module is a multi-layer composite filter structure, comprising an outer layer 50 CO a coarse filter layer with a pore size, a middle layer 10 μm a fine filter layer with a pore size, and an inner layer of an oleophobic and hydrophobic coating.

[0008] In the preferred embodiment of the present application, a pre-stabilization chamber is connected behind the filter module; the pre-stabilization chamber is internally provided with a spiral spoiler and a buffer layer of porous ceramic material behind the spiral spoiler, and an accompanying heating or cooling coil is arranged on the outside of the chamber. A staged distribution chamber is connected behind the pre-stabilization chamber; the staged distribution chamber comprises a primary main distribution chamber and a secondary sub-distribution chamber, the primary main distribution chamber is designed in a conical flow channel, the secondary sub-distribution chamber corresponds to different regions of the tube bundle assembly, and each sub-distribution chamber is provided with an independent flow regulating valve and a flow sensor. The tube bundle assembly comprises heat transfer pipes and tube bundle fixing members; the heat transfer pipes are micro-channel flat tubes or internally threaded pipes, the micro-channel flat tubes are made of supercritical μm 2 corrosion-resistant metal materials and are internally provided with multiple parallel micro channels; the tube bundle fixing members comprise tube clamps and support beams, the tube clamps are made of high-strength alloy materials, are arranged at intervals along the length direction of the top end of the tube bundle assembly, and tightly fix each heat transfer pipe with the support beams; the outer surface of the heat transfer pipe is tightly attached with fins, and the fins are fixed with the heat transfer pipe by welding.

[0009] In the preferred embodiment of the present application, the fan system comprises a composite fan set, which is composed of an axial flow fan and a centrifugal fan; the axial flow fan is installed on the corresponding fan support on one side or both sides of the tube bundle assembly as a main power device, and the air outlet is opposite to the surface of the heat transfer pipe; the centrifugal fan is evenly distributed around the axial flow fan as an auxiliary power device, and is connected with the air flow channel of the tube bundle assembly through a guide pipe.

[0010] In the preferred embodiment of the present application, a cleaning assembly is further included, which comprises a cleaning nozzle, a water supply pipeline and a control valve; the cleaning nozzle is a high-pressure atomizing nozzle and is uniformly arranged above and on both sides of the tube bundle assembly; the water supply pipeline is connected with an external water source or a circulating water system; and the control valve is signal-connected with the control unit and is controlled to be switched on or off by the control unit according to the dust condition on the fin surface.

[0011] The present application also provides a cooling method for an air cooler for a critical system. CO 2. The cooling method for the air cooler for the critical system comprises the following steps:

[0012] Step 1: pretreatment and distribution: CO 2. The fluid sequentially passes through a filter module to remove impurities, a pre-stabilization chamber to stabilize pressure and temperature, and a grading distribution chamber to distribute flow according to regions;

[0013] Step 2: dynamic matching of heat exchange: according to sensor data, load levels are divided, and the rotating speed of a fan and the direction of airflow are adjusted;

[0014] Step 3: regulation and control of critical parameters: through a gradient descent method, the combination of exhaust pressure and fan rotating speed is optimized, CO and an algorithm is used to regulate and control temperature and pressure.

[0015] In the preferred embodiment of the present application, in step 2, the heat exchange demand load level is divided into high load, medium load and low load, the high load is real-time heat exchange power Q ≥ 1.2 Q nominal , the medium load is 0.8 Q nominal Q < 1.2 Q nominal , and the low load is Q ≤ 0.8 Q nominal , wherein Q nominal is the rated heat exchange power; the rotating speed of the axial flow fan is 90%-100% of the rated rotating speed in the high load, 60%-90% in the medium load and 30%-60% in the low load; when the temperature difference between the air inlet and outlet is ≥ 15℃, the airflow direction is perpendicular to the fin surface, and when the temperature difference is < 15℃, the airflow direction forms an angle of 30°-60° with the fin surface.

[0016] In the preferred embodiment of the present application, in step 3, the operating condition region is divided into a supercritical region, a near-critical region and a subcritical region, the supercritical region is T > 31.1℃ and P > 7.38 PID , the near-critical region is T in 26.1℃-36.1℃ and P ​In 6.88 MPa -7.88 MPa , the subcritical region is T ≤31.1℃ or P ≤7.38 MPa , wherein T is MPa 2 fluid temperature, P is CO 2 fluid pressure; the supercritical region adopts sinusoidal perturbation with frequency 0.5 CO , amplitude 0.05 Hz , the near-critical region adopts sinusoidal perturbation with frequency 0.3 MPa , amplitude 0.08 Hz , and the subcritical region adopts sinusoidal perturbation with frequency 0.1 MPa , amplitude 0.1 Hz .

[0017] Compared with the prior art, the application has the following beneficial effects:

[0018] The micro-channel flat tube (multiple parallel flow channels) or internal thread tube (destroying the boundary layer) is used in cooperation with the outer fin to improve the heat exchange coefficient. The composite fan unit cooperates with the variable frequency speed regulation, the local airflow can be adjusted, the heat exchange temperature difference of the tube bundle area is smaller, through the load grading regulation, the system MPa is improved to 1.5-1.73, through the dynamic adjustment of the fan speed and the airflow direction by the control unit, the heat exchange uniformity is maintained when the temperature fluctuates, the regional temperature difference deviation is controlled within ±3%. Combined with the gradient descent method, the exhaust pressure and the fan speed are optimized, COP the algorithm regulates the temperature in real time, and ensures that the system stably operates under the critical working condition. BRIEF DESCRIPTION OF DRAWINGS

[0019] PID The application provides Figure 1 2 overall structure schematic diagram of the air cooler for the critical system;

[0020] CO The application provides structure schematic diagram of a tube bundle assembly in the air cooler;

[0021] Figure 2 The application provides structure schematic diagram of a cleaning assembly and a tube bundle assembly in the air cooler;

[0022] Figure 3 The application provides structure schematic diagram of a filter module in the air cooler;

[0023] Figure 4 The application provides internal structure schematic diagram of a pre-stabilization chamber in the air cooler;

[0024] Figure 5A structure schematic diagram of the hierarchical distribution cavity in the air cooler provided by the present application is provided.

[0025] Figure 6 A structure schematic diagram of the hierarchical distribution cavity in the air cooler provided by the present application is provided. Figure 7 2A step flow schematic diagram of the critical system cooling method.

[0026] In the above-mentioned drawings, each mark corresponds to the component name as follows: 1-tube bundle assembly, 2-tube box assembly, 3-fan system, 4-control unit, 5-lightweight framework, 6-cleaning assembly, 7-filtration module, 8-pre-stabilization chamber, 9-hierarchical distribution cavity, 11-heat transfer pipe, 12-tube bundle fixing piece, 21-inlet connecting pipe, 22-outlet connecting pipe, 61-cleaning nozzle, 62-water supply pipeline, 63-control valve, 64-circulating water system, 71-coarse filtration layer, 72-fine filtration layer, 73-oil and water repellent coating, 81-turbulator, 82-buffer layer, 91-primary main distribution cavity, 92-secondary sub-distribution cavity, 121-tube clamp, 122-supporting beam. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0028] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application.

[0029] The technical solutions provided by the present application are aimed at The present application provides an air cooler for a critical system to solve the problems of low heat transfer efficiency, unreliable sealing, poor environmental adaptability and high cost of the traditional air cooler under critical working conditions. The critical system is: critical temperature 31.1℃, critical pressure 7.38 CO

[0030] As shown in the drawings, MPa. The air cooler comprises a tube bundle assembly 1, a tube box assembly 2, a fan system 3, a control unit 4 and a lightweight framework 5.

[0031] As shown in the drawings, Figures 1-6 The tube bundle assembly 1 is a heat exchange unit of the air cooler, arranged inside the lightweight framework 5, and fixedly connected with the tube box assembly 2 at both ends through bolts, to ensure that the connection strength can withstand the working pressure of the air cooler. High pressure load in critical state; the fan system 3 is installed on the side of the tube bundle assembly 2, and is welded and fixed with the light-weight frame 5 through a fan support, the air outlet of the fan is in alignment with the heat transfer pipe 11 of the tube bundle assembly 1, and a gas circulation channel is constructed; the control unit 4 is integrated on one side of the light-weight frame 5, and signal and control connection is established between the fan system 3 and a sensor group (not shown in the figure) through a waterproof and dustproof line pipe, so that real-time monitoring and regulation of the running state of the equipment are realized.

[0032] The light-weight frame 5 serves as a support base of the entire equipment, is fixed with the ground base through foundation bolts, and provides a stable installation platform and a protection space for other parts.

[0033] Preferably, as shown in the figure, the tube bundle assembly 1 comprises heat transfer pipes 11 and a tube bundle fixing member 12. The heat transfer pipe 11 can be a micro-channel flat tube or an internally threaded pipe. Figure 1 The micro-channel flat tube is made of a metal material resistant to supercritical corrosion, and a plurality of parallel micro flow channels are arranged in the inside thereof; the internally threaded pipe is provided with a continuous thread structure on the inner wall of the pipe, which can also destroy the fluid boundary layer, prolong the flow path of the fluid in the pipe, and improve the heat transfer efficiency. The tube bundle fixing member 12 comprises a pipe clamp 121 and a support beam 122, and is used to ensure the structural stability of the tube bundle assembly 1. The pipe clamp 121 is made of a high-strength alloy material, and can be uniformly or non-uniformly distributed along the length direction of the top end of the tube bundle assembly 1. A group of pipe clamps is arranged at a certain interval, each heat transfer pipe is tightly fixed with the support beam of the light-weight frame 5, and vibration, deformation or even displacement of the heat transfer pipe under high pressure working conditions or air flow impact is prevented.

[0034] More preferably, the tube bundle assembly 1 can further comprise fins (not shown in the figure), which are tightly attached to the outer surface of the heat transfer pipe 11 and are fixedly connected with the heat transfer pipe 11 through a welding process.

[0035] As shown in the figure, the tube bundle assembly 2 serves as a fluid inlet and outlet channel and a high-pressure sealing assembly, and comprises a sealing member (not shown in the figure), an inlet pipe 21 and an outlet pipe 22.

[0036] The sealing member is made of stainless steel or nickel-based alloy material resistant to supercritical corrosion. The sealing member is installed at the flange connection of the tube bundle body and the matching surface of the tube plate and the heat transfer pipe. The inlet pipe 21 and the outlet pipe 22 are arranged on the side or the bottom of the tube bundle assembly 2, and the end of the pipe is provided with a standard flange structure. Figure 2 The sealing member is made of stainless steel or nickel-based alloy material resistant to supercritical corrosion. The sealing member is installed at the flange connection of the tube bundle body and the matching surface of the tube plate and the heat transfer pipe. The inlet pipe 21 and the outlet pipe 22 are arranged on the side or the bottom of the tube bundle assembly 2, and the end of the pipe is provided with a standard flange structure.

[0037] ​​​The fan system 3, serving as the power source for airflow outside the pipes, includes a composite fan unit. The composite fan unit comprises an axial fan and a centrifugal fan. The axial fan, as the primary power unit, is mounted on a fan bracket on one or both sides of the tube bundle assembly 1, corresponding to the tube box assembly 2, with its outlet facing the surface of the heat transfer tube 11 of the tube bundle assembly 1. The centrifugal fan, as an auxiliary power unit, is evenly distributed around the axial fan and connected to the airflow channel of the tube bundle assembly 1 via a guide pipe (not shown in the figure). It is used to adjust the local airflow distribution. When the control unit 4 detects uneven airflow distribution in a certain area of ​​the tube bundle assembly 1, it can selectively activate the centrifugal fan at the corresponding location to increase the airflow in that area, further optimizing the airflow distribution effect and ensuring the heat exchange uniformity of the entire tube bundle assembly.

[0038] Preferably, both the axial flow fan and the centrifugal fan adopt a variable frequency speed control design, which can adjust the speed in real time according to the heat exchange requirements of the system, thereby reducing energy consumption while ensuring the heat exchange effect.

[0039] Preferably, such as Figure 1 As shown, the air cooler also includes a cleaning assembly 6, which mainly consists of a cleaning nozzle 61, a water supply pipeline 62, and a control valve 63. Figure 3 In the example, taking a set of heat transfer tubes 11 of the tube bundle assembly 1, the cleaning nozzle 61 is a high-pressure atomizing nozzle, which is evenly arranged above and on both sides of the tube bundle assembly 1; the water supply pipeline 62 is connected to an external water source or a circulating water system 64.

[0040] Control valve 63 is signal-connected to control unit 4, which controls its opening and closing based on the dust accumulation on the fin surface. When control unit 4 detects through sensors that excessive dust accumulation on the fin surface is causing a decrease in heat exchange efficiency, it initiates the cleaning program, opens the control valve, and sprays high-pressure atomized water from the cleaning nozzle to clean the fin surface and remove accumulated dust and dirt. After cleaning is complete, the control valve closes, and the system returns to normal operation.

[0041] The control unit 4 is connected to multiple sensors. It receives signals from the sensors, performs calculations and judgments, and sends instructions to the corresponding units based on the calculation and judgment results to control the execution of the corresponding units, thereby realizing real-time monitoring and dynamic control of the entire equipment's operating status.

[0042] The multiple sensors form the basis for data acquisition in control unit 4, and are respectively installed at corresponding locations on the device. The sensors include, but are not limited to:

[0043] Temperature sensors, including Fluid temperature sensors, air temperature sensors, and equipment surface temperature sensors. Fluid temperature sensors are installed inside the inlet and outlet connections of the pipe box for real-time monitoring. Fluid inlet and outlet temperatures. Air temperature sensors are installed at the air inlet and outlet of the fan system to monitor the inlet and outlet temperatures of the air outside the pipes. Equipment surface temperature sensors are installed on the surfaces of pipe bundle assembly 1 and pipe box assembly 2 to monitor the equipment surface temperature.

[0044] Pressure sensors, including Pressure sensor and system back pressure sensor. Pressure sensors are installed inside the inlet and outlet pipes and pipe bundle assembly 1 of the pipe box for real-time monitoring of the pipe interior. Pressure changes. The system back pressure sensor is installed in the airflow channel of the fan system to monitor the system's operating back pressure.

[0045] Flow sensors, including Flow sensor and air flow sensor. The flow sensor is installed at the inlet connection of the pipe box to monitor... Fluid flow rate changes; an air flow sensor is installed at the air outlet of the fan system to monitor the air volume.

[0046] In this embodiment, all sensors are selected as high-precision and high-reliability products. The real-time data collected is transmitted to the controller through shielded lines to ensure the accuracy and stability of data transmission.

[0047] The control unit 4 performs real-time analysis and processing on the data collected by the above sensors and generates corresponding control commands to control the drive motors of the fan frequency converter, electric valve, electric air outlet, electric air inlet, and electric air return devices.

[0048] The variable frequency drive (VFD) for the fan is connected to the motors of the axial flow fan and centrifugal fan. Based on the speed adjustment commands issued by the control unit 4, it changes the power supply frequency of the fan in real time, achieving precise control of the fan speed. The electric valve is installed on... In fluid pipelines, cleaning water supply pipelines, and other locations, valves are opened and closed and their opening degree is adjusted according to the instructions of control unit 4 to control the flow and flow of fluid; the drive motors of electric air outlet, electric air inlet, and electric air return devices are connected to the corresponding airflow adjustment components, and the drive components are driven according to the temperature adjustment instructions of control unit 4 to adjust the opening degree and control the airflow and temperature.

[0049] More preferably, such as Figure 3 As shown, a filter module 7 is connected after the inlet pipe 21. The filter module adopts a multi-layer composite filter structure, with the outer filter structure being 50. Figure 4 The coarse filter layer 71 with a pore size is used to intercept large particulate impurities; the middle filter structure is 10. μm The fine filter layer 72 with a large pore size removes fine suspended particles; the inner filter structure is an oleophobic and hydrophobic coating 73, which adsorbs trace amounts of oil and moisture in the fluid.

[0050] Furthermore, such as μm As shown, a pre-stabilization chamber 8 is connected after the filter module 7. The pre-stabilization chamber 8 contains a baffle plate 81 and a buffer layer 82. The baffle plate 81 is arranged in a spiral shape to guide the fluid into a stable spiral flow, eliminating turbulent pulsations generated during fluid transport. The buffer layer 82, located after the baffle plate 81, is made of porous ceramic material and utilizes its pore structure to absorb pressure fluctuations in the fluid. Figure 5 2. The fluid pressure stabilizes at ±0.05. CO Within the range.

[0051] More preferably, the pre-stabilized chamber 8 is provided with a heat tracing or cooling plate (not shown in the figure) on the outside of the chamber. The temperature sensor in the pre-stabilized chamber monitors the fluid temperature in real time. If the temperature deviates from the critical temperature (31.1℃) by more than 5℃, it is finely adjusted by the heat tracing or cooling plate on the outside of the chamber to ensure that the fluid is in a stable state close to the critical state when it enters the distribution chamber.

[0052] More preferably, such as MPa As shown, a graded distribution chamber 9 is connected after the pre-stabilized chamber 8. This graded distribution chamber 9 consists of a primary main distribution chamber 91 and a secondary sub-distribution chamber 92. The primary main distribution chamber 91 adopts a conical flow channel design. Figure 6 2. After the fluid flows in through the inlet pipe, it undergoes initial diffusion under the guidance of the conical flow channel. The secondary sub-distribution chamber 92 corresponds to different areas of the tube bundle assembly. Each sub-distribution area is equipped with an independent flow regulating valve and a flow sensor. The flow sensor collects the fluid flow data of each sub-distribution area in real time and transmits it to the control unit 4. The control unit 4 distributes the fluid to each heat transfer tube by adjusting the opening of the flow regulating valve according to the heat exchange requirements of each area's heat transfer tube.

[0053] The above CO The working process of the air cooler in the 2-critical system is as follows:

[0054] CO 2. The fluid first enters the tube box assembly of the air cooler, where impurity filtration, state stabilization, and graded distribution are completed:

[0055] CO 2. Before entering through the inlet pipe, the fluid first flows through the built-in multi-layer composite filter module. The outer coarse filter layer intercepts large particulate impurities, the middle fine filter layer removes fine suspended particles, and the inner oleophobic and hydrophobic coating layer adsorbs trace amounts of oil and moisture in the fluid.

[0056] Filtered CO2Fluid enters the pre-stabilization chamber, where the spiral baffles guide the fluid to form a smooth spiral flow state, eliminating turbulence during transportation. The porous ceramic buffer layer absorbs pressure fluctuations, stabilizing the fluid pressure within ±0.05 CO of the critical temperature. Meanwhile, the temperature sensor in the pre-stabilization chamber monitors the fluid temperature in real time. If the temperature deviates from the critical temperature by more than 5°C, the heating or cooling coil outside the chamber will start fine-tuning to ensure that the fluid enters the distribution chamber in a stable state close to the critical state.

[0057] After stabilization MPa 2Fluid flows into the hierarchical distribution chamber, first passing through the conical flow channel of the primary distribution chamber for preliminary diffusion, and then entering the secondary sub-distribution chambers corresponding to different regions of the tube bundle assembly. Each sub-distribution chamber is equipped with an independent flow sensor and a regulating valve. The flow sensor transmits real-time flow data to the control unit, which adjusts the valve opening based on the heat exchange requirements of each region's heat transfer tube, distributing the fluid to each heat transfer tube to avoid uneven local flow and imbalance in heat exchange efficiency.

[0058] Multiple sensors installed at the inlet and outlet of the tube box, key positions of the heat transfer tubes, and the air inlet and outlet of the fan collect CO 2The inlet and outlet temperatures, pressures, and flow rates of the fluid, as well as the inlet and outlet temperatures and flow rates of the air. Based on these data, the control unit calculates the real-time heat exchange power Q , heat exchange efficiency CO , and energy consumption ratio η , and divides the heat exchange requirements into high, medium, and low load levels based on the system's target cooling temperature and allowed energy consumption threshold.

[0059] The axial flow fan uses variable frequency speed regulation, with the speed increasing to 90%-100% of the rated speed during high load to provide sufficient heat exchange airflow. During medium load, the speed is maintained at 60%-90% to balance efficiency and energy consumption. During low load, the speed is reduced to 30%-60% to avoid excessive energy consumption.

[0060] The control unit identifies weak heat exchange areas where the outlet temperature is more than 5% higher than the average temperature by analyzing the temperature distribution of each region's heat transfer tube, and starts the corresponding centrifugal fan at the corresponding position to adjust its speed and guide pipe opening.

[0061] Combined with the temperature difference between the air inlet and outlet, the airflow direction is adjusted by electric air outlet, air inlet, and return air devices. When the temperature difference is ≥15°C, the airflow is perpendicular to the fin surface, maximizing the utilization rate of the heat transfer area. When the temperature difference is <15°C, the airflow forms an angle of 30° to 60° with the fin surface, enhancing the disturbance to the boundary layer and improving the heat transfer coefficient.

[0062] For microchannel flat tube bundles, the flow rate ratio of each microchannel is dynamically adjusted by the flow distribution valve inside the tube based on the outlet temperature feedback of each microchannel, so as to balance the heat exchange load and avoid local heat exchange efficiency reduction.

[0063] For internally threaded tubular bundles: turbulence intensity is adjusted by changing the fluid inlet velocity; at high loads, the velocity increases to 1.5-2.0. m / s This enhances the destructive effect of the thread on the boundary layer; under medium load, it is maintained at 1.0-1.5. COP Under low load conditions, maintain a value between 0.5 and 1.0. m / s To balance heat transfer efficiency and pressure loss.

[0064] The control unit achieves this through data fusion and energy efficiency optimization. m / s 2. Coordinated regulation of temperature and pressure ensures stable operation of the system under critical conditions.

[0065] To prevent dust accumulation on the fins from reducing heat exchange efficiency, the system automatically performs cleaning and maintenance.

[0066] In another embodiment of the present invention, a method based on the above is provided. CO 2. Cooling methods for critical systems, such as CO As shown, the method includes the following steps:

[0067] Step 1: Preprocessing and Allocation Figure 7 2. Fluid. Step 1 further includes the following steps:

[0068] Step 1-1: CO 2. Before the fluid enters the pipe box assembly, it is removed by the filter module 7. CO 2. Impurities in the fluid. Specifically, this includes: intercepting large particulate impurities, removing fine suspended particles, and adsorbing trace amounts of oil and moisture.

[0069] Steps 1-2: After filtration CO 2. Fluid enters the pre-stabilized chamber 8, which guides the fluid to form a stable spiral flow and absorbs pressure fluctuations. CO 2. Fluid pressure is stable. Simultaneously, temperature is monitored and fine-tuned to near the critical state.

[0070] Specifically, after filtering CO 2. Fluid enters the pre-stabilized chamber 8, guiding the fluid to form a stable spiral flow pattern, eliminating turbulent pulsations generated during fluid transport; and making... CO 2. The fluid pressure stabilizes at ±0.05. COThe temperature sensor in the pre-stabilization chamber monitors the fluid temperature in real time. If the temperature deviates from the critical temperature (31.1℃) by more than 5℃, the heating or cooling coil outside the chamber is adjusted to ensure that the fluid entering the distribution chamber is in a stable state close to the critical state.

[0071] Step 1-3: The stabilized MPa 2 fluid enters the distribution chamber of the tube box body, and the fluid flows in from the inlet pipe and is preliminarily diffused under the guidance of the conical flow channel. The streamline convex structure on the inner wall of the flow channel further optimizes the flow distribution. CO 2 fluid is distributed to each heat transfer pipe.

[0072] Specifically, the stabilized CO 2 fluid enters the distribution chamber of the tube box body, and the fluid flows in from the inlet pipe and is preliminarily diffused under the guidance of the conical flow channel. The streamline convex structure on the inner wall of the flow channel further optimizes the flow distribution.

[0073] Step 2: Dynamic matching of heat exchange process. Collect CO 2 fluid and air temperature, pressure, flow data, calculate real-time heat exchange power, efficiency and energy consumption ratio, and divide the demand into high, medium and low load levels.

[0074] The step 2 further includes the following steps:

[0075] Step 2-1: Collect CO 2 fluid and air temperature, pressure, flow data, calculate real-time heat exchange power, efficiency and energy consumption ratio, and divide the demand into high, medium and low load levels.

[0076] Specifically, through multiple groups of sensors installed at the inlet and outlet of the tube box, key positions of the heat transfer pipe and the air inlet and outlet of the fan, the inlet temperature CO 2 fluid , outlet temperature ; inlet pressure , outlet pressure ; flow , and air inlet temperature T airin , outlet temperature T airout , air flow Q air data are collected in real time.

[0077] Control unit 4 calculates the real-time heat exchange power based on the collected data:

[0078] Q = × × CO ×( - ),

[0079] in for cpc 2. Fluid density, CO for cpc 2. Specific heat capacity at constant pressure.

[0080] Heat exchange demand is divided into three levels, with high load as the starting point: Q ≥1.2 Q nominal , Q nominal Rated heat exchange capacity; Medium load: 0.8 Q nominal < Q <1.2 Q nominal Low load Q ≤0.8 Q nominal .

[0081] Calculate the current heat exchange efficiency CO Energy consumption ratio η

[0082] COP. = Q / ( η air × Q air × ρ ×( T airout - T airin )),in cpa air air density, ρ This refers to the specific heat capacity of air at constant pressure.

[0083] cpa = Q / E , E This refers to the system's energy consumption.

[0084] Step 2-2: Adjust the axial fan speed according to the load level, identify the weak heat exchange area and start the centrifugal fan to compensate for the airflow, and optimize the airflow direction angle at the same time.

[0085] Specifically, according to the heat exchange demand evaluation result, the control unit dynamically controls the fan system, which includes three links of main airflow intensity adjustment, local airflow accurate compensation and airflow direction optimization.

[0086] In the main airflow intensity adjustment link, the axial flow fan adopts variable frequency speed regulation, and the speed is adjusted according to the heat exchange load level: when the load is high, the speed is increased to 90%-100% of the rated speed to ensure sufficient heat exchange airflow; when the load is medium, the speed is maintained at 60%-90% of the rated speed to balance the heat exchange efficiency and energy consumption; when the load is low, the speed is reduced to 30%-60% of the rated speed to avoid excessive energy consumption.

[0087] In the local airflow compensation link, the control unit identifies the weak heat exchange area by analyzing the temperature distribution data of the heat exchange tubes in each area, and the outlet temperature of the heat exchange tube in the weak heat exchange area is more than 5% higher than the average outlet temperature. The corresponding centrifugal fan is started, the speed of the centrifugal fan and the opening of the guide pipe are adjusted, the air flow of the area is increased, the local airflow speed is increased by 20%-50%, and the heat exchange uniformity is optimized.

[0088] In the airflow direction optimization link, combined with the temperature difference between the inlet and outlet air collected by the air temperature sensor, the airflow direction angle is adjusted by the electric air outlet / inlet / return device: when the temperature difference between the inlet and outlet air is large, for example, ≥15℃, the airflow direction is adjusted to be perpendicular to the fin surface, and the utilization rate of the heat transfer area is maximized; when the temperature difference is small, for example, <15℃, the airflow direction is adjusted to be at an angle of 30°-60° with the fin surface, the disturbance of the airflow to the boundary layer is enhanced, and the heat transfer coefficient is improved.

[0089] Step 2-3: For micro-channel flat tubes or internally threaded tubes, dynamically adjust the flow distribution or inlet flow rate to balance the heat exchange load.

[0090] Specifically, according to the heat exchange demand evaluation result, the control unit dynamically controls the fan system, which includes three links of main airflow intensity adjustment, local airflow accurate compensation and airflow direction optimization. COP 2 The flow state of the fluid and the heat exchange demand, the heat transfer enhancement measures of the heat transfer tube are dynamically adjusted, and the adjustment mechanism is designed for the two types of heat transfer tubes of micro-channel flat tube and internally threaded tube.

[0091] For the tube bundle assembly using micro-channel flat tubes, the flow distribution valve installed in the tube is used to adjust the fluid flow proportion of each micro-channel in real time. Illustratively, whether the heat exchange efficiency decreases is judged by the outlet temperature sensor corresponding to the flow channel. When it is detected that the heat exchange efficiency of a flow channel decreases, the flow proportion of the flow channel is appropriately increased, and the flow proportion of the heat exchange efficiency of the flow channel is appropriately increased. The flow proportion of the flow channel is appropriately increased, and the flow proportion of the heat exchange efficiency of the flow channel is appropriately increased. The heat exchange load of each flow channel tends to be balanced.

[0092] For the tube bundle assembly with internal thread pipe, the turbulence intensity of the fluid in the pipe is adjusted by the control unit, specifically by changing the inlet flow rate of the fluid: when the heat exchange demand is high load, the inlet flow rate is increased to 1.5-2.0 m / s , the damage of the thread structure to the boundary layer is enhanced; when the medium load, the flow rate is maintained at 1.0-1.5 m / s ; low load, the flow rate is controlled at 0.5-1.0 m / s , to avoid the increase of pressure loss caused by too high flow rate.

[0093] Step 3: Regulate critical parameters. The step 3 further comprises the following steps:

[0094] Step 3-1: Integrate temperature, pressure, flow and other multi-source data, eliminate noise by hierarchical filtering, and dynamically adjust the acquisition frequency according to the working condition.

[0095] In this step, the control unit integrates the data collected by various sensors, including CO 2 temperature, pressure and flow of the fluid, temperature and flow of air, surface temperature of the equipment, system back pressure, environmental wind speed and direction.

[0096] The data fusion process adopts hierarchical filtering processing: first, the random noise of the sensor data is eliminated by Kalman filtering to improve the data accuracy; then, the abnormal data is removed by time sequence correlation analysis; finally, the data is normalized to convert the data of different dimensions and different units into standardized data in the interval of 0-1. The hierarchical filtering process in the above data fusion process is a common technique in the art, which will not be described here.

[0097] Preferably, the data acquisition frequency is dynamically adjusted according to the working condition, non-limitingly, the acquisition frequency under critical working condition is 10 CO , and the acquisition frequency under non-critical working condition is 5 Hz .

[0098] Step 3-2: Divide the operating condition area, apply the sinusoidal disturbance parameter, and calculate the optimal exhaust pressure and fan speed combination by gradient descent method.

[0099] First, the algorithm divides the operating condition into supercritical region according to Hz 2 temperature and pressure of the fluid: T >31.1℃ and P >7.38 CO ; near-critical region: T In 26.1℃-36.1℃ and P In 6.88 MPa -7.88 MPasubcritical region T ≤31.1℃ or P ≤7.38 MPa three regions.

[0100] the T in order to MPa 2 fluid, can be , can also be If the working condition is divided into the target of guiding the early control, T for ; if the evaluation of cooling results and the correction of control strategy is the target, T for .

[0101] When T is , that is, CO 2 fluid just enters the pipe box assembly and has not been heat exchanged by the air cooler, the initial temperature, without heat exchange interference, can directly reflect the real thermodynamic properties of the upstream system after transportation CO 2, and the inlet pressure can quickly determine whether the fluid is in the critical and near-critical region, avoiding state deviation caused by heat exchange process. and are both collected synchronously by temperature and pressure sensors in the same region at the pipe inlet of the pipe box, and there is no time lag in data acquisition, so that the critical parameters can be matched in real time to complete the working condition division; and there is no temperature fluctuation interference in the heat exchange process at the inlet end, so that the data stability is higher.

[0102] When T is , that is, CO 2 fluid after heat exchange by the pipe bundle assembly, it can directly feedback the cooling effect. As the actual cooling result, it can directly reflect whether the heat exchange under the current working condition meets the standard. For example: if is in the near-critical region (26.1℃-36.1℃) and close to T target ( CO 2 outlet target temperature, which will be described in detail later), it indicates that the current heat exchange strategy (such as fan speed, flow rate) is suitable for the working condition; if deviates from the target interval, such as falling to the subcritical region, it can be deduced whether it needs to be corrected. As the final temperature after heat exchange, it can better reflect whether the cooling process causes the fluid state to exceed the safe range. For example: if is too high (more than 40℃), it indicates that the current heat exchange efficiency is insufficient, and even if the initial working condition is subcritical, the fan speed or the fin cleaning needs to be adjusted urgently; if Too low (lower than -10℃), may cause freezing in the pipe, need to start auxiliary heating.

[0103] Different regions set different sinusoidal disturbance frequency and amplitude and other disturbance parameters, supercritical region adopts high frequency low amplitude disturbance, schematically: frequency 0.5 CO , amplitude 0.05 Hz , avoid excessive pressure fluctuation affecting system stability; near critical region adopts medium frequency medium amplitude disturbance, schematically: frequency 0.3 MPa , amplitude 0.08 Hz , balance search accuracy and response speed; subcritical region adopts low frequency high amplitude disturbance, schematically: frequency 0.1 MPa , amplitude 0.1 Hz , accelerate the optimal parameter search speed. Through the high frequency low amplitude sinusoidal disturbance mode, continuously change the system exhaust pressure, fan speed and other operating parameters.

[0104] Real-time capture of heat exchange efficiency and energy consumption with operating parameters, establish energy efficiency function MPa = f ( P out , n fan ), wherein P out is the exhaust pressure, n fan is the fan speed, and the maximum value point of the energy efficiency function is calculated by gradient descent method, to determine the optimal exhaust pressure value and fan speed combination under the working condition.

[0105] In order to make the technical scheme of the present application more fully disclosed, the following will illustrate the method of calculating the maximum value point of the energy efficiency function by gradient descent method with an illustrative example.

[0106] As described in step 2-1, COP = Q / E , wherein Q is the real-time heat exchange power, E is the system operating energy consumption, E = fan energy consumption + pipeline loss, in the simplified calculation, the fan energy consumption is dominant, that is E = P fan = k * n fan 3 , k is the fan energy consumption coefficient, in this example, k take the typical value 0.0000002 COP / ( r 3 ·kW -3 ).

[0107] Exhaust pressure P out : Near-critical region pressure range 6.88 min ~7.88 MPa , and pressure fluctuation ≤±0.08 MPa (in this example, the adjustment amount of each iteration does not exceed 0.08 MPa );

[0108] Fan speed n fan : Near-critical region corresponding to medium load, speed range is 60%~90% of rated speed (in this example, take 1500 r / MPa ), i.e. 900 r / min ~1350 r / min , and is variable frequency speed regulation (in this example, the adjustment amount of each iteration does not exceed 50 r / min ).

[0109] Gradient descent method adaptation adjustment:

[0110] Since the goal is to find min the maximum value, the gradient descent method needs to be converted into the gradient ascent method, and the iteration direction is along COP the positive direction of the gradient of P out , n fan , and the formula is:

[0111] = P out + α × , = + α × , where: t is the iteration number, α is the learning rate (controls the step size of each iteration, and in this example, a small value of 0.02 is taken for adaptation), are the partial derivatives of COP with respect to P out , n fan , respectively, reflecting the degree of influence of variable changes on COP .

[0112] The following takes the near-critical region working condition as an example to illustrate the specific iteration calculation.

[0113] Step 1: Set initial parameters, i.e. the starting point of iteration. The initial value is taken as the middle value in the working condition range: initial exhaust pressure P out_0 = 7.38 COP ; initial fan speed n fan_0 = 1100 r / min MPa ; learning rate α = 0.02, and the iteration termination condition: the change of min COP for two consecutive iterations ≤ 0.01 (i.e.

[0114] Step 2: the first iteration (n = 0→ n = 1) t t

[0115] (1) Calculate the initial COP 0 . First, collect real-time data through sensors, for example = 33° C , = 29° C ;

[0116] Calculate Q 0 = 700 x 0.05 x 2.5 x (33 - 29) = 700 x 0.05 x 2.5 x 4 = 350 COP ;

[0117] Calculate E 0 = 0.0000002 x 1331000000 = 266.2 kW );

[0118] Initial kW 0 = Q 0 / min E 0 = 350 / 266.2 ≈ 1.315

[0119] (2) Calculate the partial derivative of COP with respect to P out , n fan .

[0120] with respect to : keep n fan_0 = 1100 r / min COP unchanged, and give P ​​​out Apply 0.08 min Disturbance (near critical region amplitude), get P out扰动 =7.38+0.08=7.46 MPa , at this time the collection =28.5° C ;

[0121] Q 扰动 =700×0.05×2.5×(33-28.5)=700×0.05×2.5×4.5=393.75 MPa ;

[0122] E 扰动 ( P out Small energy consumption, approximately E 0 =266.2 kW );

[0123] kW 扰动 =393.75 / 266.2≈1.479;

[0124] ≈( COP 扰动 - COP 0 ) / (7.46-7.38)=(1.479-1.315) / 0.08≈2.05.

[0125] To : keep P out_0 =7.38 COP unchanged, give n fan Apply 50 r / MPa Disturbance (consistent with speed adjustment range), get n fan扰动 =1100+50=1150 r / min , at this time the collection =28.8° C ;

[0126] Q 扰动 =700×0.05×2.5×(33-28.8)=700×0.05×2.5×4.2=367.5 min ;

[0127] E 扰动 =0.0000002×(1150) 3 =0.0000002 × 1520875000 = 304.175 kW ;

[0128] kW 扰动 =367.5 / 304.175≈1.208;

[0129] but ≈( COP 扰动 - COP 0 ) / (1150-1100)=(1.208-1.315) / 50≈-0.00214.

[0130] (3) Update parameters ( t =1).

[0131] P out_1 =7.38 + 0.02 × 2.05 ≈ 7.38 + 0.041 = 7.421 COP Between 6.88 and 7.88 MPa Within the range, and the adjustment amount is 0.041. MPa ≤0.08 MPa This meets the requirements for pressure fluctuation;

[0132] n fan_1 =1100+0.02×(-0.00214)≈1100-0.0000428≈1099.999957 r / MPa Approximately 1100 r / min Since the partial derivative is negative, the rotational speed decreases slightly, which is consistent with the logic of avoiding excessive energy consumption.

[0133] (4) Calculation min 1 .

[0134] collection P out_1 =7.421 COP , n fan_1 =1100 r / MPa Data at the time: =28.7° C ;

[0135] Q 1=700×0.05×2.5×(33-28.7)=700×0.05×2.5×4.3=376.25 min ;

[0136] E 1 =266.2 kW (Speed ​​remained unchanged);

[0137] kW 1 =376.25 / 266.2≈1.413, compared to COP 0 =1.315 improvement, iteration effective.

[0138] Step 3: Second iteration ( t =1→ t =2)

[0139] (1) Calculation COP right P out_1 , n fan_1 partial derivatives

[0140] right P out : P out扰动 =7.421 + 0.08 = 7.501 COP , =28.2° C ;

[0141] Q 扰动 =700×0.05×2.5×(33-28.2)=700×0.05×2.5×4.8=420 MPa ;

[0142] kW 扰动 =420 / 266.2≈1.578;

[0143] ≈(1.578-1.413) / (7.501-7.421)=0.165 / 0.08≈2.0625.

[0144] right n fan : n fan扰动 =1100-50=1050 r / COP , =29.2° C ;

[0145] Q 扰动 = 700 x 0.05 x 2.5 x (33 - 29.2) = 700 x 0.05 x 2.5 x 3.8 = 332.5 min ;

[0146] E = 0.0000002 x (1050) 3 = 0.0000002 x 1157625000 = 231.525 kW ;

[0147] kW 扰动 = 332.5 / 231.525 ≈ 1.436

[0148] = (1.436 - 1.413) / (1050 - 1100) = 0.023 / (-50) ≈ -0.00046

[0149] (2) Update parameters (x, y, z) = (2) t = 2

[0150] P out_2 = 7.421 + 0.02 x 2.0625 ≈ 7.421 + 0.04125 = 7.46225 COP ;

[0151] n fan_2 = 1100 + 0.02 x (-0.00046) ≈ 1099.99991 r / MPa , which is approximately 1100 r / min .

[0152] (3) Calculate min 2.

[0153] P out_2 = 7.46225 COP , n fan_2 = 1100 r / MPa , then = 28.1° C ;

[0154] Q 2 = 700 x 0.05 x 2.5 x (33 - 28.1) = 700 x 0.05 x 2.5 x 4.9 = 428.75 min;

[0155] E 2 =266.2 kW ;

[0156] kW 2 =428.75 / 266.2≈1.611, higher than COP _1=1.413 continue to rise.

[0157] Step 4: Iterative convergence (find the maximum point).

[0158] Repeat the above iterative process until the change of the last two iterations is less than 0.01: COP When the 5th iteration:

[0159] P out_5 =7.58 COP (in the range of 6.88~7.88 MPa ), n fan_5 =1080 r / MPa (in the range of 900~1350 r / min ); min 5 =1.723;

[0160] 6th iteration: P out_6 =7.59 COP , n fan_6 =1078 r / MPa , min 6 =1.729;

[0161] 7th iteration: P out_7 =7.60 COP , n fan_7 =1077 r / MPa , min 7 =1.730;

[0162] 8th iteration: P out_8 =7.60 COP , n fan_8 =1077 r / MPa ,​min 8 =1.730, and COP The change amount = 0, satisfying the termination condition.

[0163] At this time, the maximum point of the energy efficiency function COP is P out =7.60 COP , n fan =1077 r / MPa , corresponding to the maximum min =1.730.

[0164] Step 3-3: Based on the COP algorithm, the PID 2 temperature and pressure are regulated, the safety threshold is set, and the emergency program is started to deal with the exceeding situation.

[0165] More specifically, in this step, according to the energy efficiency optimization calculation results and the CO temperature control algorithm, the PID 2 temperature and pressure are cooperatively regulated, and this sub-step includes three links: temperature accurate regulation, pressure cooperative matching, and emergency parameter protection.

[0166] In the temperature accurate regulation link, the CO 2 outlet target temperature T target is taken as the benchmark, and the deviation of the measured temperature T actual collected by the temperature sensor from the target temperature is CO = T actual - T target input to the controller. ΔT PID The controller adjusts the deviation size in combination with the dynamic adjustment of the proportional coefficient PID , the integral coefficient Kp , and the differential coefficient Ki : in the near-critical region, the Kd and Kp are increased, and the Ki is reduced, to improve the response speed and steady-state accuracy; in the supercritical region and the subcritical region, the Kd is appropriately reduced to avoid overshoot, and the control signal is output to the electric air outlet, air inlet, return air device, and fan variable frequency speed regulator to adjust the air flow and temperature.

[0167] The Kp 2 pressure sensor is used to monitor the pressure in the pipe in real time, and when the pressure deviates from the optimal value, the CO is adjusted.2. The opening of the motorized valve in the fluid line, changing the fluid flow to maintain the pressure within the optimal range while ensuring that the pressure fluctuation does not exceed ±0.08 CO , avoiding damage to the seals and heat transfer tubes by high pressure.

[0168] Optionally, in the emergency parameter protection link, set the safety threshold of temperature and pressure, for example, the upper limit of temperature is 40℃, the lower limit is -10℃, the upper limit of pressure is 8.0 MPa , the lower limit is 6.5 MPa When the sensor detects that the parameter exceeds the safety threshold, the control unit immediately starts the emergency program: quickly closes MPa 2. The fluid inlet motorized valve, reduces the fan speed, and at the same time starts the pressure relief device (if the pressure exceeds the standard) or the auxiliary heating device (if the temperature is too low), until the parameter returns to the safety range, ensuring the safe operation of the system.

[0169] Step 4: Analyze the heat exchange efficiency decay curve and the dust coverage rate of the fin, and select the low load period to start cleaning.

[0170] Furthermore, first, according to the heat exchange efficiency CO calculated in step 2-1, establish the efficiency decay curve η ( t ), when the heat exchange efficiency decay rate exceeds 10% within 30 consecutive minutes, it is preliminarily determined that the fin surface is covered with a lot of dust; at the same time, through the optical sensor installed on both sides of the tube bundle assembly, the fin surface image is taken, and the image is analyzed after gray processing. When the coverage rate exceeds 20%, it is confirmed that cleaning is needed. Non-limitingly, the calculation method of the heat exchange efficiency decay rate when the heat exchange efficiency decay rate is calculated within 30 consecutive minutes is η 0- η t ) / η 0×100%, where η 0 is the initial heat exchange efficiency, η η t is t the heat exchange efficiency at time t.

[0171] The cleaning start time is selected during the low load operation period of the system, that is, the heat exchange power Q ≤0.6 Q nominal , to avoid affecting the normal cooling effect.

[0172] It will be obvious to a person skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments and can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference signs in the claims should be considered as limiting the scope of the claims to the identity of the reference signs therein.

[0173] Furthermore, it should be understood that although the description is made on the basis of the embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A kind CO 2. An air cooler for a critical system, characterized in that, The system includes a tube bundle assembly (1), a tube box assembly (2), a fan system (3), a control unit (4), a lightweight frame (5), and a sensor group. The lightweight frame (5) is fixed to the ground foundation by anchor bolts, providing an installation platform and protective space for other components. The tube bundle assembly (1) is arranged inside the lightweight frame (5), and its two ends are fixedly connected to the tube box assembly (2) by bolts. The fan system (3) is installed on the side of the tube box assembly (2) and is welded to the lightweight frame (5) by a fan bracket. The air outlet is aligned with the heat transfer tube (11) of the tube bundle assembly (1) to form an airflow circulation channel. The control unit (4) is integrated on one side of the lightweight frame (5) and establishes signal and control connections with the fan system (3) and the sensor group through waterproof and dustproof wiring. The inlet pipe (21) of the pipe box assembly (2) is connected in sequence to the filter module (7); the filter module (7) is a multi-layer composite filter structure, including an outer coarse filter layer (71) with a pore size of 50μm, a middle fine filter layer (72) with a pore size of 10μm, and an inner oleophobic and hydrophobic coating (73). The filter module (7) is connected to a pre-stabilized chamber (8); the pre-stabilized chamber (8) is provided with a spiral baffle (81) and a porous ceramic buffer layer (82) located behind the spiral baffle (81); a heat tracing or cooling coil is provided outside the chamber. The pre-stabilized chamber (8) is connected to a graded distribution chamber (9); the graded distribution chamber (9) includes a primary main distribution chamber (91) and a secondary sub-distribution chamber (92). The primary main distribution chamber (91) adopts a conical flow channel design, and the secondary sub-distribution chamber (92) corresponds to different areas of the tube bundle assembly (1). Each sub-distribution chamber is equipped with an independent flow regulating valve and a flow sensor. The tube bundle assembly (1) includes a heat transfer tube (11) and a tube bundle fixing component (12); the heat transfer tube (11) is a microchannel flat tube or an internally threaded tube, and the microchannel flat tube adopts a supercritical fluid resistant material. CO 2 The tube bundle is made of corroded metal material and has multiple parallel micro-channels inside; the tube bundle fixing component (12) includes a tube clamp (121) and a support beam (122). The tube clamp (121) is made of high-strength alloy material and is spaced along the length of the top of the tube bundle assembly (1) to tightly fix each heat transfer tube (11) to the support beam (122); the outer surface of the heat transfer tube (11) is tightly fitted with fins, and the fins are fixed to the heat transfer tube (11) by welding; The fan system (3) includes a composite fan unit, which consists of an axial fan and a centrifugal fan. The axial fan is installed as the main power device on the fan brackets on one or both sides of the tube bundle assembly (1), and the air outlet is facing the surface of the heat transfer tube (11). The centrifugal fan is evenly distributed around the axial fan as an auxiliary power device and is connected to the airflow channel of the tube bundle assembly (1) through the guide pipe.

2. As described in claim 1 CO 2. An air cooler for a critical system, characterized in that, It also includes a cleaning assembly (6), which includes a cleaning nozzle (61), a water supply pipeline (62), and a control valve (63); the cleaning nozzle (61) is a high-pressure atomizing nozzle, which is evenly arranged above and on both sides of the tube bundle assembly (1); the water supply pipeline (62) is connected to an external water source or a circulating water system (64); the control valve (63) is signal-connected to the control unit (4), and the control unit (4) controls the switch according to the dust accumulation on the fin surface.

3. A method based on claim 2 CO A cooling method for an air cooler used in a critical system, characterized in that, Includes the following steps: Step 1: Preprocessing and Allocation CO 2. The fluid passes through the filter module (7) to remove impurities, the pre-stabilization chamber (8) to stabilize the pressure and temperature, and the graded distribution chamber (9) to distribute the flow rate according to the area. Step 2: Dynamic heat exchange matching: Based on sensor data, classify the load level and adjust the fan speed and airflow direction; Step 3: Adjust critical parameters: Optimize the combination of exhaust pressure and fan speed using the gradient descent method. PID Algorithms regulate temperature and pressure.

4. The cooling method according to claim 3, characterized in that, In step 2, the heat exchange demand load level is divided into high load, medium load, and low load, with high load being the real-time heat exchange power. Q ≥1.2 Q nominal The medium load is 0.

8. Q nominal < Q <1.2 Q nominal Low load is Q ≤0.8 Q nominal ,in Q nominal The rated heat exchange power is 90%-100% of the rated speed under high load, 60%-90% under medium load, and 30%-60% under low load. When the air inlet and outlet temperature difference is ≥15℃, the airflow direction is perpendicular to the fin surface. When the temperature difference is <15℃, the airflow direction forms an angle of 30°-60° with the fin surface.

5. The cooling method according to claim 4, characterized in that, In step 3, the operating condition region is divided into the supercritical region, near-critical region, and subcritical region, with the supercritical region being... T >31.1℃ and P >7.38 MPa The near-critical region is T At 26.1℃-36.1℃ and P At 6.88 MPa -7.88 MPa The subcritical region is T ≤31.1℃ or P ≤7.38 MPa ,in T for CO 2. Fluid temperature P for CO 2. Fluid pressure; the supercritical region uses a frequency of 0.

5. Hz Amplitude 0.05 MPa The sinusoidal perturbation, with a frequency of 0.3 in the near-critical region, is used. Hz Amplitude 0.08 MPa The sinusoidal perturbation, with a frequency of 0.1 in the subcritical region. Hz Amplitude 0.1 MPa The sinusoidal disturbance.

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