Control method of air-suspended variable-frequency centrifugal cold water machine based on variable temperature difference control and energy storage thermal management system

Abstract

The application discloses a control method of an air-suspension variable-frequency centrifugal cold water machine energy storage heat management system based on variable temperature difference control. The water outlet temperature and the water return temperature of the air-suspension variable-frequency centrifugal cold water machine are detected first. When the water outlet temperature reaches a first preset value, the speed of the compressor is controlled based on the difference between the water outlet temperature and the water return temperature according to a first equation obtained through pre-calibration. When the water outlet temperature reaches a second preset value, the speed of the compressor is controlled based on the water return temperature and the ambient temperature according to a second equation obtained through pre-calibration, wherein the second preset value is greater than the first preset value. Based on the variable temperature difference control logic, the speed of the compressor can be smoothly adjusted according to the changes of the thermal load and the water temperature, unnecessary start and stop are avoided, mechanical impact on the compressor and other system components can be reduced, the service life of the whole equipment is prolonged, invalid energy consumption can be avoided, and the energy utilization efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of energy storage thermal management technology, and in particular to a control method and energy storage thermal management system for an air-suspended variable frequency centrifugal chiller based on variable temperature difference control. Background Technology

[0002] With the widespread application of energy storage technology, the requirements for the stability and reliability of its thermal management system are increasing. In the field of energy storage thermal management, energy storage chillers and energy storage liquid chillers play a key role. The air-suspension variable frequency centrifugal chiller is a high-efficiency refrigeration equipment that uses an air-suspension centrifugal compressor as its core and combines permanent magnet synchronous variable frequency direct drive technology. It can achieve oil-free and frictionless operation of rotating parts, and therefore is currently widely used in energy storage thermal management systems.

[0003] However, air-suspended variable frequency centrifugal chillers always carry a surge risk when operating at low speeds. The energy storage battery compartment only generates heat load during charging and discharging. As the load gradually decreases or disappears, the refrigeration module will experience a drop in system outlet water temperature due to the reduced load, leading to an increase in the compressor pressure ratio. This increased pressure ratio causes the compressor's surge speed to increase, resulting in an increase in the actual speed. Consequently, the refrigeration module will quickly reach its shutdown temperature setpoint and stop. This phenomenon contradicts the objective fact that the compressor speed should decrease with a reduced load.

[0004] Traditional cooling module control methods fail to fully consider the complex relationships between compressor surge, load changes, and water temperature variations. Using only simple temperature control strategies cannot flexibly adjust compressor speed according to dynamic changes in actual heat load, leading to frequent module start-ups and shutdowns. This not only affects the stable operation of the energy storage thermal management system but also shortens equipment lifespan and increases maintenance costs. Furthermore, frequent start-ups and shutdowns result in energy waste and reduced overall system energy efficiency, contradicting current energy conservation and environmental protection requirements. In scenarios such as data centers where cooling module stability is extremely critical, such frequent start-ups and shutdowns can even affect data storage and processing, causing unpredictable losses. Summary of the Invention

[0005] To address some or all of the problems in the existing technology, and in order to achieve stable and efficient operation of the refrigeration module, the first aspect of this invention provides a control method for an air-suspended variable frequency centrifugal chiller energy storage thermal management system based on variable temperature difference control, comprising: Detect the outlet and return water temperatures of the air-suspension variable frequency centrifugal chiller; When the outlet water temperature reaches a first preset value, the compressor speed is controlled based on the difference between the outlet water temperature and the return water temperature according to a first equation obtained through pre-calibration. When the outlet water temperature reaches a second preset value, the compressor speed is controlled based on the return water temperature and the ambient temperature according to a second equation obtained through pre-calibration, wherein the second preset value is greater than the first preset value.

[0006] Furthermore, the calibration of the first equation and the second equation includes: The outlet water temperature of the air-suspended variable frequency centrifugal chiller is changed in a fixed step. At each outlet water temperature value, after the parameters of the air-suspended variable frequency centrifugal chiller stabilize, the outlet water temperature, return water temperature, compressor speed, and water flow rate are collected. The collected effluent and reflux temperatures are fitted to obtain the fitting equation between the effluent temperature and the inlet and outlet temperature difference. The collected outlet water temperature, inlet and outlet water temperature difference, and compressor speed are fitted to obtain the fitting equations for the inlet and outlet water temperature difference and compressor speed, namely the first equation and the second equation.

[0007] Furthermore, the fixed step is 0.3 degrees Celsius.

[0008] Furthermore, during the calibration process, the inlet water flow rate, pressure, ambient temperature, and humidity of the air-suspension variable frequency centrifugal chiller remain unchanged.

[0009] Furthermore, the initial operating condition is calibrated as a variable rated cooling capacity with a 0°C temperature difference between the inlet and outlet water.

[0010] Furthermore, the outlet water temperature of the air-suspension variable frequency centrifugal chiller can be changed by adjusting the compressor speed.

[0011] Furthermore, the fitting equations for the outlet water temperature and the inlet / outlet water temperature difference, and the fitting equations for the inlet / outlet water temperature difference and the compressor speed are obtained through interpolation.

[0012] Based on the control method described above, a second aspect of the present invention provides an energy storage thermal management system, comprising: Air-suspension variable frequency centrifugal chiller; Temperature sensors are installed at both ends of the cooling component to detect the outlet and return water temperatures of the air-suspended variable frequency centrifugal chiller. The control module controls the air-suspension variable frequency centrifugal chiller using the control method described above.

[0013] Furthermore, the air-suspension variable frequency centrifugal chiller includes: The refrigeration module includes an air-suspension variable frequency centrifugal compressor, a condenser, a liquid receiver, a dryer filter, and an expansion valve; The cooling module includes a water pump and a cooling circuit. The cooling circuit is located at the component to be cooled and cools the component by means of coolant. The cooling module exchanges heat with the refrigeration module through a heat exchange module.

[0014] This invention provides a control method and energy storage thermal management system for an air-suspended variable frequency centrifugal chiller based on variable temperature difference control. Based on variable temperature difference control logic, the compressor speed can be smoothly adjusted according to changes in heat load and water temperature, avoiding unnecessary start-ups and shutdowns. This reduces mechanical impact on the compressor and other system components, decreases component wear, extends the overall service life of the equipment, and ensures long-term stable system operation. Simultaneously, the compressor speed decreases appropriately as the heat load decreases, avoiding ineffective energy consumption. The slow decrease in system water temperature also reduces the additional energy consumption caused by rapid cooling followed by reheating, improving energy utilization efficiency and reducing operating costs. Furthermore, by fitting an equation relating the inlet and outlet water temperature difference to the compressor's safe operating speed, the compressor speed is precisely controlled, always remaining above the surge speed, ensuring safe and reliable operation under various conditions. For scenarios with extremely high temperature control requirements, such as energy storage battery compartments, a stable and reliable refrigeration system can provide a suitable working environment for the batteries, ensuring battery performance and lifespan, and improving the overall reliability and safety of the energy storage system. The control method described has good versatility and flexibility. Whether for small-scale energy storage projects or large-scale data center energy storage thermal management, the system can adapt to different heat load requirements and equipment specifications by adjusting control parameters, thus expanding its application scope. Furthermore, the control method based on data calibration and equation fitting makes the control process more scientific and precise, enhancing the overall intelligence level of the energy storage thermal management system. Attached Figure Description

[0015] To further illustrate the above and other advantages and features of the various embodiments of the present invention, a more specific description of the various embodiments of the present invention will be presented with reference to the accompanying drawings. It is to be understood that these drawings depict only typical embodiments of the invention and are therefore not intended to limit its scope. In the drawings, identical or corresponding parts will be indicated by identical or similar reference numerals for clarity.

[0016] Figure 1 This diagram illustrates the structure of an energy storage thermal management system according to an embodiment of the present invention. Figure 2 This diagram illustrates a control method for an air-suspended variable frequency centrifugal chiller based on variable temperature difference control, according to an embodiment of the present invention. Figure 3 This diagram illustrates the relationship between compressor speed and outlet water temperature according to an embodiment of the present invention. Figure 4 This diagram illustrates a test calibration process according to an embodiment of the present invention.

[0017] List of reference numerals 001 Refrigeration module, 011 Air-suspension variable frequency centrifugal compressor, 012 Condenser, 013 Throttling device, 014 Fan, 015 Liquid receiver, 016 Dryer filter 002 Intermediate heat exchanger 003 Cooling module, 031 Water pump 101 Temperature Sensor Detailed Implementation In the following description, the invention is described with reference to various embodiments. However, those skilled in the art will recognize that the embodiments may be practiced without one or more specific details or with other alternatives and / or additional methods, materials, or components. In other instances, well-known structures, materials, or operations are not shown or described in detail so as not to obscure the inventive points of the invention. Similarly, for illustrative purposes, specific quantities, materials, and configurations are set forth to provide a comprehensive understanding of embodiments of the invention. However, the invention is not limited to these specific details. Furthermore, it should be understood that the embodiments shown in the drawings are illustrative representations and are not necessarily drawn to scale.

[0018] In this specification, references to "an embodiment" or "this embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. The phrase "in one embodiment" appearing throughout this specification does not necessarily refer to the same embodiment in all instances.

[0019] It should be noted that the embodiments of the present invention describe the method steps in a specific order; however, this is only for illustrating the specific embodiment and not for limiting the order of the steps. On the contrary, in different embodiments of the present invention, the order of the steps can be adjusted according to actual needs.

[0020] To address the problem of frequent start-stop cycles in existing refrigeration system control methods, this invention provides a control method for an air-suspended variable frequency centrifugal chiller based on variable temperature difference control. This method employs a controlled variable approach to precisely control the temperature difference between the inlet and outlet water, satisfying the actual requirement of a corresponding decrease in compressor speed during heat load reduction while ensuring stable system water temperature changes. Specifically, starting with a 0°C inlet-outlet water temperature difference and varying rated cooling capacity, a comprehensive test calibration is performed on the outlet water temperature at specified intervals. During each calibration, key parameters such as outlet water temperature, return water temperature, and compressor speed are recorded in detail. Based on the calibration data, equations are fitted to the return water temperature and the inlet-outlet water temperature difference, as well as the equations to the compressor's safe operating speed. Then, during actual operation, once the system outlet water temperature reaches the preset value, as the water temperature further decreases, the compressor speed will strictly adhere to the equations relating the inlet-outlet water temperature difference to the compressor's safe operating speed. This means that as the system heat load decreases, the compressor speed can gradually decrease, ensuring that the compressor operates within a safe range and preventing surge phenomena. Furthermore, the system water temperature will decrease slowly, unlike traditional systems which reach the compressor shutdown temperature setpoint quickly, thus effectively reducing the frequency of refrigeration system start-stop cycles. As mentioned earlier, the variable temperature difference control logic not only meets the actual requirement of a corresponding decrease in compressor speed during heat load reduction but also ensures stable changes in system water temperature. This significantly improves the stability and reliability of the entire system. Regarding system stability, it avoids the impact on system components caused by frequent compressor start-stop cycles, reducing component wear and extending the overall service life of the equipment. In terms of reliability, it ensures the continuous and stable operation of the energy storage thermal management system under various complex operating conditions, providing a stable and reliable temperature control environment for the energy storage battery compartment and guaranteeing the normal operation of the energy storage system.

[0021] The present invention will be further described below with reference to the accompanying drawings of the embodiments.

[0022] Figure 1 A schematic diagram of the structure of an energy storage thermal management system according to an embodiment of the present invention is shown. Figure 1 As shown, an energy storage thermal management system includes a control module (not shown), a temperature sensor, and an air-suspension variable frequency centrifugal chiller. The air-suspension variable frequency centrifugal chiller includes a refrigeration module 001, an intermediate heat exchanger 002, and a cooling module 003. The refrigeration module 001 circulates refrigerant to cool the coolant, and the cooling module 003 circulates coolant to cool the module to be cooled. The refrigeration module 001 and the cooling module 003 are coupled through the intermediate heat exchanger 002. Figure 1As shown, the core component of the refrigeration module 001 is an air-suspension variable frequency centrifugal compressor 011. The air inlet of the air-suspension variable frequency centrifugal compressor 011 is connected to an intermediate heat exchanger 002. The high-temperature, low-pressure refrigerant, after heat exchange with the coolant in the intermediate heat exchanger, enters the air-suspension variable frequency centrifugal compressor 011 for compression, forming a refrigerant in its first state. In one embodiment of the invention, the air-suspension variable frequency centrifugal compressor 011 includes a motor, an impeller, an air inlet, an exhaust outlet, and a connecting pipe. The motor includes a rotor system, a stator, and a housing. Figure 1 As shown, the refrigeration module 001 further includes a condenser 012 and a throttling device 013. The inlet of the condenser 012 is connected to the exhaust port of the air-suspension variable frequency centrifugal compressor 011, used to cool the refrigerant in the first state to obtain a refrigerant in the second state. The temperature of the refrigerant in the second state is lower than that of the refrigerant in the first state, but the pressure remains essentially unchanged. In one embodiment of the invention, to improve refrigeration efficiency, a fan 014 is also provided at the fins of the condenser 012. The fan 014 introduces ambient temperature air into the fins of the condenser 012, allowing the heat of the high-temperature refrigerant inside the condenser 012 to exchange with the air, thereby achieving condensation. The throttling device 013 is connected to the outlet of the condenser 012 to throttle the refrigerant in the second state. The throttled refrigerant rapidly expands to form a third state. The pressure of the refrigerant in the third state is lower than that of the refrigerant in the second state, but the temperature remains essentially unchanged. The refrigerant in the third state enters an intermediate heat exchanger to exchange heat with the coolant. In embodiments of the present invention, the throttling device refers to a device or component used to reduce gas pressure to achieve evaporation, such as an expansion valve, capillary tube, or throttling tube. To calculate the system's cooling demand and thus control the operating status of each device or module, and to protect system operation, in one embodiment of the present invention, a temperature sensor T and a pressure sensor P are also provided in the refrigeration module 001. As shown in the figure, the temperature sensor T and pressure sensor P can be located, for example, at the first outlet of the intermediate heat exchanger and / or the exhaust port of the air-suspension variable frequency centrifugal compressor. Figure 1 As shown, the refrigeration module 001 also includes a liquid receiver 015 and a dryer filter 016, which are connected to the outlet of the condenser 012.

[0023] The intermediate heat exchanger includes two inlets and two outlets, thus forming refrigerant pipelines and coolant pipelines. The inlet and outlet of the refrigerant pipeline are designated as the first inlet and the first outlet. The first inlet is connected to the throttling device 013, and the first outlet is connected to the air inlet of the air-suspension variable frequency centrifugal compressor 011. The inlet and outlet of the coolant pipeline are designated as the second inlet and the second outlet, respectively connected to the inlet and outlet of the pipeline in the cooling module. The coolant pipeline is arranged around the refrigerant pipeline to allow heat exchange between the coolant and refrigerant. In one embodiment of the invention, a plate heat exchanger is used as the intermediate heat exchanger.

[0024] As shown in the figure, in one embodiment of the present invention, the core component of the cooling module 003 is a water pump 031, which provides power for the circulation of the coolant. The water pump 031 is connected to the second inlet of the intermediate heat exchanger via a water pipe, and sends the coolant into the intermediate heat exchanger. After transferring heat to the refrigerant, the coolant reaches the module to be cooled through the pipeline. The heat generated by the module to be cooled, such as the cell of an energy storage battery, is transferred to the coolant, and the heated coolant returns to the water pump, thus circulating. In one embodiment of the present invention, in order to improve heat exchange efficiency, the flow direction of the coolant in the intermediate heat exchanger is exactly opposite to the flow direction of the refrigerant. For example, the first inlet and the second outlet of the intermediate heat exchanger can be set on the first side of the intermediate heat exchanger, and the second inlet and the first outlet can be set on the second side of the intermediate heat exchanger opposite to the first side. The temperature sensor 101 is set at both ends of the module to be cooled, and is used to measure the outlet water temperature and return water temperature of the air-suspended variable frequency centrifugal chiller, respectively.

[0025] Figure 2 This diagram illustrates a flow chart of a control method for an air-suspended variable frequency centrifugal chiller based on variable temperature difference control, according to an embodiment of the present invention. It can be used for controlling, for example... Figure 1 The energy storage thermal management system shown includes: First, in step 201, the outlet and return water temperatures are detected. The outlet water temperature of the air-suspension variable frequency centrifugal chiller is measured. and return water temperature The temperature of the coolant flowing out of the air-suspended variable frequency centrifugal chiller is determined by real-time detection of the coolant temperature using temperature sensors located at both ends of the module to be cooled. The temperature of the coolant that returns to the air-suspended variable frequency centrifugal chiller after heat exchange with the module to be cooled. After receiving the data measured by the temperature sensor, the control module calculates the temperature difference between the inlet and outlet water. ; Next, in step 202, the compressor speed is controlled. When the outlet water temperature reaches the first preset value, i.e., the minimum outlet water temperature, the compressor speed is controlled based on the difference between the outlet water temperature and the return water temperature to ensure the need for slow cooling as the heat load decreases, and also to ensure that the compressor speed is far from the surge speed and within the safe operating range. When the outlet water temperature reaches the second preset value, the compressor speed is controlled based on the return water temperature and the ambient temperature to ensure the need for rapid cooling as the heat load increases, and also to ensure that the compressor alarms for excessively high discharge pressure when the ambient temperature is too high and that the compressor remains within the safe operating range. Figure 3 As shown. The first preset value is determined based on the design conditions of the energy storage thermal management system. In one embodiment of the invention, the first preset value is 1 to 10 degrees Celsius higher than the evaporation temperature of the energy storage thermal management system, preferably 5 degrees Celsius. The second preset value is a deviation from the first preset value, determined based on the power and heat dissipation of the module to be cooled, for example, based on the capacity and rate of the energy storage battery compartment, and its range is 2 to 10 degrees Celsius. In one embodiment of the invention, the compressor speed is controlled based on the difference between the outlet water temperature and the return water temperature, or the difference between the return water temperature and the ambient temperature, according to a pre-calibrated equation. In one embodiment of the invention, the calibration of the equation includes: First, an experimental platform was built, and the energy storage thermal management system was fully connected to ensure that all components were operating normally and that the data acquisition system was accurate and reliable. Next, set the initial operating condition to 0°C temperature difference between inlet and outlet water and rated cooling capacity, and record the initial system parameters at this time, including but not limited to system inlet water flow rate, pressure, ambient temperature, humidity and other parameters that may affect the experimental results. Next, the system's inlet and outlet water temperatures are gradually changed according to a fixed step. At each outlet water temperature setpoint, the system is run stably for a period of time. After the system parameters stabilize, key data such as outlet water temperature, return water temperature, compressor speed, and water flow rate are collected. It should be understood that to ensure the accuracy and reliability of the collected data, the calibration process requires strict control of other variables. For example, the system's inlet water flow rate is kept constant by adjusting the water pump frequency, and environmental control equipment such as a constant temperature and humidity laboratory is used to maintain stable ambient temperature and humidity. The calibration is completed within the entire temperature difference range, obtaining a series of data sets, each including outlet water temperature, return water temperature, and compressor speed. In one embodiment of the invention, the fixed step is 0.3 degrees Celsius, meaning the system's inlet and outlet water temperatures are gradually changed at 0.3°C intervals. In another embodiment of the invention, the outlet water temperature of the air-suspended variable frequency centrifugal chiller is changed by adjusting the compressor speed. Specifically, as... Figure 4As shown, the test calibration includes the following steps: First, when the unit is shut down, as the initial operating condition, the corresponding outlet water temperature is T-out1. The actual compressor speed is adjusted to S1, and the compressor speed S1, return water temperature T-in1, outlet water temperature T-out1, and inlet / outlet water temperature difference are recorded. And the system water flow rate F, then adjust the actual compressor speed to S2 so that the Xiyong outlet water temperature T-out2 = T-out1 + 0.3, and record the compressor speed S2, return water temperature T-in2, outlet water temperature T-out2, and inlet and outlet water temperature difference. And the system water flow rate F, and so on, until the outlet water temperature reaches its maximum value; Next, the collected data sets will be fitted using mathematical fitting methods, such as the least squares method, to derive equations for the outlet water temperature and the inlet / outlet water temperature difference. This will reflect the variation patterns of the inlet and outlet water temperatures under different inlet / outlet water temperature differences, and thus reflect the variation patterns of the heat load. Simultaneously, for the data on outlet water temperature, inlet / outlet water temperature difference, and compressor safe operating speed, appropriate fitting algorithms will be used to obtain equations for these parameters and the compressor's safe operating speed, providing a basis for compressor speed control.

[0026] Similarly, equations relating return water temperature, ambient temperature, and the safe operating speed of the compressor can also be calibrated.

[0027] In one embodiment of the present invention, the control method further includes issuing an alarm immediately and recording relevant data when system parameters are detected to be outside the normal range or abnormal conditions occur, such as abnormal fluctuations in compressor speed or rapid changes in water temperature, so that maintenance personnel can promptly investigate the cause of the fault, reduce downtime and losses caused by the fault, and thus ensure the efficient operation of the energy storage thermal management system.

[0028] This invention provides a control method and energy storage thermal management system for an air-suspended variable frequency centrifugal chiller based on variable temperature difference control. Based on variable temperature difference control logic, the compressor speed can be smoothly adjusted according to changes in heat load and water temperature, avoiding unnecessary start-ups and shutdowns. This reduces mechanical impact on the compressor and other system components, decreases component wear, extends the overall service life of the equipment, and ensures long-term stable system operation. Simultaneously, the compressor speed decreases appropriately as the heat load decreases, avoiding ineffective energy consumption. The slow decrease in system water temperature also reduces the additional energy consumption caused by rapid cooling followed by reheating, improving energy utilization efficiency and reducing operating costs. Furthermore, by fitting an equation relating the inlet and outlet water temperature difference to the compressor's safe operating speed, the compressor speed is precisely controlled, always remaining above the surge speed, ensuring safe and reliable operation under various conditions. For scenarios with extremely high temperature control requirements, such as energy storage battery compartments, a stable and reliable refrigeration system can provide a suitable working environment for the batteries, ensuring battery performance and lifespan, and improving the overall reliability and safety of the energy storage system. The control method described has good versatility and flexibility. Whether for small-scale energy storage projects or large-scale data center energy storage thermal management, the system can adapt to different heat load requirements and equipment specifications by adjusting control parameters, thus expanding its application scope. Furthermore, the control method based on data calibration and equation fitting makes the control process more scientific and precise, enhancing the overall intelligence level of the energy storage thermal management system.

[0029] Although various embodiments of the invention have been described above, it should be understood that they are presented by way of example only and not as limitations. It will be apparent to those skilled in the art that various combinations, modifications, and alterations can be made without departing from the spirit and scope of the invention. Therefore, the breadth and scope of the invention disclosed herein should not be limited by the exemplary embodiments disclosed above, but should be defined solely by the appended claims and their equivalents.

Claims

1. A control method for an air-suspension variable frequency centrifugal chiller energy storage thermal management system based on variable temperature difference control, characterized in that, include: Detect the outlet and return water temperatures of the air-suspension variable frequency centrifugal chiller; When the outlet water temperature reaches a first preset value, the compressor speed is controlled based on the difference between the outlet water temperature and the return water temperature according to a first equation obtained through pre-calibration. When the outlet water temperature reaches a second preset value, the compressor speed is controlled based on the return water temperature and the ambient temperature according to a second equation obtained through pre-calibration, wherein the second preset value is greater than the first preset value.

2. The control method as described in claim 1, characterized in that, The calibration of the first and second equations includes: The outlet water temperature of the air-suspended variable frequency centrifugal chiller is changed in a fixed step. At each outlet water temperature value, after the parameters of the air-suspended variable frequency centrifugal chiller stabilize, the outlet water temperature, return water temperature, compressor speed, and water flow rate are collected. The collected effluent and reflux temperatures are fitted to obtain the fitting equation between the effluent temperature and the inlet and outlet temperature difference. The collected outlet water temperature, inlet and outlet water temperature difference, and compressor speed are fitted to obtain the fitting equations for the inlet and outlet water temperature difference and compressor speed, namely the first equation and the second equation.

3. The control method as described in claim 2, characterized in that, The fixed step is 0.3 degrees Celsius.

4. The control method as described in claim 2, characterized in that, During the calibration process, the inlet water flow rate, pressure, ambient temperature, and humidity of the air-suspension variable frequency centrifugal chiller remain unchanged.

5. The control method as described in claim 2, characterized in that, The initial operating condition is calibrated to a 0°C temperature difference between the inlet and outlet water, with the rated cooling capacity varying.

6. The control method as described in claim 2, characterized in that, The outlet water temperature of the air-suspension variable frequency centrifugal chiller can be changed by adjusting the compressor speed.

7. The control method as described in claim 2, characterized in that, The fitting equations for the outlet water temperature and the inlet / outlet water temperature difference, and the fitting equations for the inlet / outlet water temperature difference and the compressor speed are obtained by interpolation.

8. An energy storage thermal management system, characterized in that, include: Air-suspension variable frequency centrifugal chiller; Temperature sensors are located at both ends of the cooling component and are configured to detect the outlet and return water temperatures of the air-suspended variable frequency centrifugal chiller. A control module that controls the air-suspension variable frequency centrifugal chiller using the control method described in any one of claims 1 to 7.

9. The energy storage thermal management system as described in claim 8, characterized in that, The air-suspension variable frequency centrifugal chiller includes: The refrigeration module includes an air-suspension variable frequency centrifugal compressor, a condenser, a liquid receiver, a dryer filter, and a throttling device; The cooling module includes a water pump and a cooling circuit. The cooling circuit is located at the component to be cooled and cools the component by means of coolant. The cooling module exchanges heat with the refrigeration module through a heat exchange module.

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