A pressurized hot water pressure storage heat system and operation method for compressed air energy storage

Abstract

The application constructs a compressed air energy storage pressurized hot water pressure storage heat system and an operation method, the system comprises a high-pressure hot water storage tank, a normal-pressure cold water storage tank, an independent gas storage tank and matched fluid conveying pipelines and gas pipelines, which are divided into a liquid phase area and a gas phase space from bottom to top. During energy storage, cold water is sent into the high-pressure hot water storage tank through pressurization and heat absorption, and a gas pressurizing device pressurizes the extruded protective gas and stores it into the independent gas storage tank; during energy release, the high-pressure hot water releases heat and returns to the normal-pressure cold water storage tank through a pressure reducing assembly, and a gas supply regulating valve synchronously injects the protective gas into the high-pressure hot water storage tank to supplement pressure. The application cancels the low-temperature high-pressure container through high and low pressure asymmetric fluid architecture, reduces the construction cost, and cuts off the connection of cold and hot gas, thereby reducing the pressure oscillation hidden danger.

Description

Technical Field

[0001] This invention relates to the field of compressed air energy storage technology, and in particular to a pressurized hot water partial pressure thermal storage system for compressed air energy storage and its operation method. Background Technology

[0002] Non-combustion compressed air energy storage systems require the recovery of heat during the compression phase and the reuse of this heat during the power generation phase. The thermodynamic performance and fluid circulation stability of the energy storage system determine the overall conversion efficiency and continuous operation capability of the energy storage power station. Constructing a physical circulation architecture capable of safely and stably storing high-temperature and high-pressure media is the engineering foundation for ensuring the long-term stable operation of large-capacity physical energy storage systems.

[0003] Currently, common thermal storage methods primarily use water as the storage medium, often employing a symmetrical physical topology with two pressurized tanks. In this conventional approach, both the high-temperature hot water tank and the low-temperature cold water tank are designed as heavy-duty pressure vessels capable of withstanding the same high pressure level, interconnected via gas spaces at the top of the tanks to maintain overall system pressure balance. However, when the fluid repeatedly switches between the two high-pressure tanks, the gas circulates between the tanks with significant temperature differences, causing alternating physical temperatures and gas volume, resulting in continuous fluctuations in gas density and consequently frequent oscillations in the system's back pressure. Furthermore, maintaining the high-pressure operating environment on the low-temperature side requires a large-volume cold-pressurized vessel with the same wall thickness and material grade as the high-temperature side, leading to redundancy at the pressure-bearing material boundaries.

[0004] Existing thermal energy storage systems are prone to fluid pressure instability caused by coupled oscillations of the gas-phase thermodynamic state during long-term variable load charging and discharging cycles, and the volumetric pressure-bearing efficiency of the hardware system is low. Therefore, it is necessary to study a novel thermal energy storage fluid circulation method that can balance pipeline back pressure stability with lightweight container configuration, in order to improve the overall operational reliability of large-scale energy storage systems under complex operating conditions. Summary of the Invention

[0005] Purpose of the invention: To provide a pressurized hot water partial pressure thermal storage system and its operation method using compressed air energy storage, in order to solve the above-mentioned problems existing in the prior art.

[0006] Technical solution: A pressurized hot water partial pressure thermal storage system using compressed air energy storage, comprising a high-pressure hot water storage tank, an atmospheric pressure cold water storage tank, an independent gas storage tank, cold water delivery pipelines, hot water delivery pipelines, and a gas pipeline network, including:

[0007] The internal cavity of the high-pressure hot water storage tank is divided into a liquid phase zone and a gas phase space from bottom to top;

[0008] The atmospheric pressure cold water storage tank has an internal atmospheric pressure water storage cavity;

[0009] Independent gas storage tanks have a high-pressure gas storage chamber inside;

[0010] The cold water delivery pipeline connects the internal cavities of the atmospheric pressure cold water storage tank and the high pressure hot water storage tank. A cold water booster pump and a main heat exchanger are connected in series along the fluid flow direction on the cold water delivery pipeline, and the outlet end of the cold water delivery pipeline extends to the liquid phase region of the internal cavity of the high pressure hot water storage tank.

[0011] The hot water delivery pipeline connects the internal cavity of the high-pressure hot water storage tank to the atmospheric pressure cold water storage tank. The upstream end of the hot water delivery pipeline is connected to the liquid phase region of the internal cavity of the high-pressure hot water storage tank. A hot water circulation pump, an air heater, and a pressure reducing component are connected in series along the fluid flow direction on the hot water delivery pipeline.

[0012] The gas pipeline network connects the gas phase space of the high-pressure hot water storage tank and the high-pressure gas storage chamber of the independent gas storage tank. The gas pipeline network includes a first gas line and a second gas line that are independent of each other. The upstream end of the first gas line is connected to the gas phase space of the high-pressure hot water storage tank, and the downstream end is connected to the independent gas storage tank. A gas pressure boosting device is connected in series on the first gas line. The upstream end of the second gas line is connected to the independent gas storage tank, and the downstream end is connected to the gas phase space of the high-pressure hot water storage tank. A gas supply regulating valve is installed on the second gas line.

[0013] Furthermore, the pressure reducing assembly includes a single-stage pressure reducing valve and a bypass reflux unit;

[0014] A single-stage pressure reducing valve is connected in series on the hot water delivery pipeline and is located between the air heater and the atmospheric pressure cold water storage tank;

[0015] The bypass return unit includes a bypass pipeline and a bypass valve installed on the bypass pipeline. The upstream end of the bypass pipeline is connected to the hot water delivery pipeline between the air heater and the single-stage pressure reducing valve, and the downstream end is connected to the internal cavity of the high-pressure hot water storage tank.

[0016] Furthermore, the physical volume of the independent gas storage tank is configured as a static parameter boundary, the physical volume being equal to the product of the effective liquid phase volume change in the liquid phase region within the high-pressure hot water storage tank during a single energy storage and release cycle and the rated operating pressure of the high-pressure hot water storage tank, divided by the pressure difference between the design maximum pressure of the independent gas storage tank and the rated operating pressure of the high-pressure hot water storage tank.

[0017] The gas phase space inside the high-pressure hot water storage tank retains a minimum safe gas phase volume to prevent liquid from entering the gas pipeline network at the highest operating liquid level.

[0018] Furthermore, the pressure reducing assembly includes a first-stage pressure reducing valve, an intermediate flash tank, and a second-stage pressure reducing valve connected in series along the fluid flow direction. The intermediate flash tank has an internal cavity for vapor-liquid separation, and the liquid phase outlet at the bottom of the intermediate flash tank is connected to the inlet of the second-stage pressure reducing valve.

[0019] The pressure reducing assembly also includes a preheating heat exchanger. The vapor phase outlet at the top of the intermediate flash tank is connected to the hot side inlet of the preheating heat exchanger via a steam pipeline. The hot side outlet of the preheating heat exchanger is connected to the atmospheric pressure cold water storage tank. The cold side of the preheating heat exchanger is connected in series to the cold water delivery pipeline between the atmospheric pressure cold water storage tank and the main heat exchanger.

[0020] Furthermore, the operation method of the pressurized hot water partial pressure thermal storage system includes:

[0021] During the energy storage phase, the system receives atmospheric cold water from an atmospheric cold water storage tank; pressurizes the atmospheric cold water and performs heat exchange treatment by absorbing the heat of compression to obtain high-pressure hot water; and injects the high-pressure hot water into the liquid phase region of a high-pressure hot water storage tank for storage.

[0022] The system simultaneously receives the initial protective gas squeezed out of the high-pressure hot water storage tank due to the rise in the liquid level in the liquid phase zone; it uses a gas pressurization device to pressurize the initial protective gas to obtain pressurized protective gas; and it discharges the pressurized protective gas into an independent gas storage tank for storage.

[0023] During the energy release phase, high-pressure hot water is received from the high-pressure hot water storage tank; the high-pressure hot water is used to heat the air to be expanded to obtain heat release return water; the pressure reduction component is used to depressurize the heat release return water to obtain atmospheric pressure low-temperature water; the atmospheric pressure low-temperature water is sent back to the atmospheric pressure cold water storage tank.

[0024] It synchronously receives pressurized protective gas from an independent gas storage tank; based on the volume change caused by the drop in liquid level in the liquid phase zone inside the high-pressure hot water storage tank, it injects pressurized protective gas into the gas phase space of the high-pressure hot water storage tank through a gas supply regulating valve to maintain the internal operating pressure of the high-pressure hot water storage tank at the rated operating pressure.

[0025] Furthermore, before the step of depressurizing the returned water after heat release using a pressure reducing assembly, a flash evaporation prevention safety control step is also included:

[0026] Real-time acquisition of the current return water temperature after heat release;

[0027] Obtain the pre-configured temperature safety threshold and compare the current return water temperature with the temperature safety threshold;

[0028] When the current return water temperature is higher than the temperature safety threshold, the interlock protection mechanism is triggered. Specifically, the operation of depressurizing the return water after heat release using the pressure reducing component is stopped, and the preset bypass return path is opened to guide the return water after heat release back to the liquid phase zone of the high-pressure hot water storage tank for circulation.

[0029] The operation of depressurizing the returned water after heat release will resume once the current return water temperature is detected to drop below the safe temperature threshold.

[0030] Furthermore, during the switch from the energy storage phase to the energy release phase, the seamless switching control is performed according to the following timing sequence:

[0031] Gradually reduce the operating frequency of the chilled water booster pump until it stops, and simultaneously control the gas booster device to slow down until it stops.

[0032] Close the first gas line;

[0033] Open the gas supply regulating valve to the preset initial opening value and monitor and confirm that the internal operating pressure of the high-pressure hot water storage tank has reached the initial pressure stabilization state;

[0034] Start the hot water circulation pump and activate the pressure reducing component to establish a complete energy release fluid channel;

[0035] During the entire operating condition switching and system operation cycle, the first air circuit and the air supply regulating valve are simultaneously in the open state.

[0036] Furthermore, after the energy storage phase ends, a step to compensate for the loss of protective gas is also included:

[0037] Obtain the current endpoint pressure within an independent gas storage tank;

[0038] Obtain the design maximum pressure of the pre-configured independent gas storage tank, and calculate the lower limit threshold of the allowable pressure based on the preset pressure loss ratio;

[0039] Compare the current endpoint pressure with the lower limit threshold of the allowable pressure;

[0040] When the current endpoint pressure is lower than the lower limit threshold of the allowable pressure, it is determined that there is gas leakage loss in the system. The external gas supply channel connected to the system is connected to obtain external compensation protection gas provided by the external gas source and inject it into the independent gas storage tank.

[0041] When the internal pressure of the independent gas storage tank is detected to return to the design maximum pressure, the external gas supply channel is shut off.

[0042] Furthermore, prior to the initial energy storage phase, an initial pressurization and reservoir preparation step is included for cold start-up of the system:

[0043] Connect to an external initial gas source and continuously inject gas into the high-pressure hot water storage tank and the independent gas storage tank until the pressure in the high-pressure hot water storage tank reaches the rated operating pressure.

[0044] Start the cold water booster pump to inject high-pressure hot water that has undergone heat exchange, and at the same time, use the gas booster device to continuously transfer the gas squeezed out by the rising liquid level to the independent gas storage tank.

[0045] When the liquid phase zone inside the high-pressure hot water storage tank reaches the designed maximum liquid level, the system is initially pressurized and the control system enters normal operation standby state.

[0046] Furthermore, during the extended period of quiescent operation between the energy storage and energy release phases, a quiescent pressure maintenance step is implemented:

[0047] Continuously monitor the internal operating pressure of the high-pressure hot water storage tank;

[0048] When the internal operating pressure falls below the preset static maintenance lower limit due to heat loss during static operation, the gas supply regulating valve is opened to perform a small pressure replenishment operation.

[0049] When the internal operating pressure returns to the target set value, close the gas supply regulating valve to maintain stable system pressure during the resting period.

[0050] Beneficial effects: This invention eliminates the need for cryogenic high-pressure containers through a high-low pressure asymmetric fluid architecture, reducing construction costs and cutting off the connection between hot and cold gases, thus reducing the risk of pressure oscillation. Attached Figure Description

[0051] Figure 1 This is a flowchart illustrating the process of determining the operating parameters of the gas pressurization device in an embodiment of this application.

[0052] Figure 2 This is a flowchart illustrating the calculation of the feedforward speed command for the gas booster device in an embodiment of this application.

[0053] Figure 3 This is a flowchart of the anti-flash evaporation safety control in the embodiments of this application.

[0054] Figure 4 This is a flowchart illustrating the process of seamless switching control of operating conditions in an embodiment of this application.

[0055] Figure 5 This is a schematic diagram of a pressurized hot water partial pressure heat storage system in an embodiment of this application.

[0056] In the diagram: 1. Independent nitrogen storage tank; 2. Nitrogen booster pump; 3. High-pressure hot water storage tank; 4. Gas supply regulating valve; 5. Heat exchanger; 6. Cold water booster pump; 7. Atmospheric pressure cold water storage tank; 8. Hot water circulation pump; 9. Air heater; 10. Shut-off valve; 11. Pressure reducing valve; 12. Flash tank. Detailed Implementation

[0057] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0058] Example 1: This example provides a pressurized hot water partial pressure thermal storage system for compressed air energy storage. The system includes a high-pressure hot water storage tank, an atmospheric pressure cold water storage tank, an independent gas storage tank, a cold water delivery pipeline, a hot water delivery pipeline, and a gas pipeline network.

[0059] As an alternative implementation, the internal cavity of the high-pressure hot water storage tank is divided into a liquid phase zone and a gas phase space from bottom to top.

[0060] Optionally, high-pressure hot water storage tanks are used to store high-temperature, high-pressure fluids that have absorbed heat from the air compression process. Since the stored fluids generate saturated vapor pressure at high temperatures, high-pressure hot water storage tanks must be manufactured using pressure-resistant, pressure-bearing vessel materials. The internal cavity is divided based on density differences under gravity, forming natural physical stratification. The lower part is filled with high-temperature fluid, forming a liquid phase region, while the upper part, filled with protective gas, forms a gas phase space. The gas phase space maintains a certain volume ratio range throughout the entire energy storage and release cycle of the system. This structure not only provides a buffer for the expansion and contraction of the liquid phase volume but also constitutes the physical interface for subsequent protective gas recovery and injection.

[0061] Optionally, the atmospheric pressure cold water storage tank has an internal atmospheric pressure water storage cavity.

[0062] Correspondingly, atmospheric pressure cold water storage tanks are used to temporarily store the cryogenic fluid after the energy release and heat excitation process has been completed. The physical pressure of the atmospheric pressure storage cavity is configured to be the normal environmental pressure in equilibrium with the external atmospheric pressure. In actual engineering deployments, atmospheric pressure cold water storage tanks can adopt conventional non-pressurized thin-walled container structures, and their construction costs and material grade requirements are far lower than those of pressurized high-pressure hot water storage tanks. This separation design of high-pressure and atmospheric pressure physical structures, unlike the isobaric equilibrium mode in traditional thermal storage systems where both cold water and hot water storage tanks are designed as high-pressure containers, reduces the initial investment scale of the system from the hardware architecture perspective.

[0063] Optionally, the independent gas storage tank has a high-pressure gas storage chamber inside.

[0064] Furthermore, the independent gas storage tank, as an auxiliary component connecting the hot and cold storage tank fluid circulation system, is used to contain and temporarily store the high-pressure protective medium required by the system during circulation. The volume and pressure-bearing capacity of the independent gas storage tank are matched and set according to the overall circulation volume of the system. Its internal high-pressure gas storage chamber is isolated from the water circulation system and only participates in the exchange of gas phase volume.

[0065] In some optional embodiments, the high-pressure protective gas stored in the high-pressure gas storage chamber can be any one of nitrogen, carbon dioxide, argon, or dry air. Preferably, nitrogen is used as the high-pressure protective gas, mainly because nitrogen has relatively stable chemical properties and does not react chemically with water or system pipe walls during long-term operation. This avoids oxygen corrosion problems under high temperature and high pressure environments, which is beneficial to ensuring the safety and long service life of the system container.

[0066] Optionally, the cold water delivery pipeline connects the internal cavities of the atmospheric pressure cold water storage tank and the high-pressure hot water storage tank. The internal cavity of the high-pressure hot water storage tank is divided into a liquid phase zone and a gas phase space from bottom to top. A cold water booster pump and a main heat exchanger are connected in series along the fluid flow direction on the cold water delivery pipeline, and the outlet end of the cold water delivery pipeline extends to the liquid phase zone of the internal cavity of the high-pressure hot water storage tank.

[0067] Accordingly, the chilled water delivery pipeline constitutes the main channel for fluid transmission during the energy storage phase. Atmospheric-pressure chilled water is pressurized by a chilled water booster pump to reach the rated operating pressure level matching the high-pressure hot water storage tank. The pressurized chilled water then enters the main heat exchanger, where it exchanges heat with the high-temperature compressed air generated between the compressor stages or at the exhaust end of the compressed air energy storage system, absorbing heat to form high-pressure hot water. Further, the high-pressure hot water is injected into the liquid phase region inside the high-pressure hot water storage tank via the outlet of the chilled water delivery pipeline to complete the physical storage of thermal energy.

[0068] Optionally, the hot water delivery pipeline connects the internal cavity of the high-pressure hot water storage tank to the atmospheric pressure cold water storage tank. The upstream end of the hot water delivery pipeline is connected to the liquid phase region of the internal cavity of the high-pressure hot water storage tank, and a hot water circulation pump, an air heater, and a pressure reducing component are connected in series along the fluid flow direction on the hot water delivery pipeline.

[0069] In this embodiment, the hot water delivery pipeline constitutes the main channel for fluid transmission during the energy release phase. Upon initiation of energy release, the high-temperature, high-pressure hot water stored in the liquid phase is extracted by the hot water circulation pump and delivered to the air heater. In the air heater, the high-pressure hot water transfers its heat energy to the compressed air that is about to enter the expander to perform work, while its own temperature decreases. The cooled water then enters the pressure reducing assembly, where its pressure is steadily adjusted from high pressure to atmospheric pressure, and finally discharged as atmospheric pressure chilled water into the atmospheric pressure chilled water storage tank, completing the closed-loop fluid recovery process.

[0070] Optionally, the gas pipeline network connects the gas phase space of the high-pressure hot water storage tank and the high-pressure gas storage chamber of the independent gas storage tank. The gas pipeline network includes a first gas path and a second gas path that are independent of each other. The upstream end of the first gas path is connected to the gas phase space of the high-pressure hot water storage tank, and the downstream end is connected to the independent gas storage tank. A gas pressure boosting device is connected in series on the first gas path. The upstream end of the second gas path is connected to the independent gas storage tank, and the downstream end is connected to the gas phase space of the high-pressure hot water storage tank. A gas supply regulating valve is installed on the second gas path.

[0071] Furthermore, the gas pipeline network establishes a pressure adaptive closed loop for the system during dynamic changes in liquid level. In energy storage mode, the continuous injection of high-pressure hot water into the liquid phase zone causes a continuous rise in liquid level, continuously compressing the gas phase space. The squeezed-out high-pressure protective gas enters the first gas path, is further pressurized by the gas pressurization device, and is then properly stored in the high-pressure gas storage chamber of the independent gas storage tank. In energy release mode, as hot water is extracted from the liquid phase zone, the liquid level drops, causing the gas phase space to expand. At this time, the high-pressure protective gas stored in the independent gas storage tank flows back through the second gas path. Utilizing the flow control function of the gas supply regulating valve, a suitable flow rate of high-pressure protective gas is smoothly injected into the gas phase space, which helps to ensure that the internal pressure of the high-pressure hot water storage tank maintains dynamic balance throughout the fluid filling and releasing process. Through the separate configuration of the first and second gas paths, the system achieves unidirectional control of gas flow, avoiding the risks of backflow or pressure turbulence.

[0072] Example 2: This example further details the relationship between volume and pressure configuration in a pressurized hot water partial pressure heat storage system.

[0073] In one possible implementation, the physical volume of the independent gas storage tank is configured with static parameter boundaries, the physical volume being determined by the effective liquid phase volume change in the liquid phase region within the high-pressure hot water storage tank during a single energy storage and release cycle, the product of the rated operating pressure of the high-pressure hot water storage tank, the pressure difference between the design maximum pressure of the independent gas storage tank and the rated operating pressure of the high-pressure hot water storage tank, and the temperature and compressibility factor of nitrogen under each state.

[0074] This embodiment provides the static boundary constraint logic for the system during the offline design and selection phase. After eliminating the traditional pressurized cold water storage tank, the system relies on an independent gas storage tank to absorb the volume displacement caused by the charge-discharge heat cycle of the fluid. To achieve the goal of reducing overall cost in engineering implementation, the physical capacity of the independent gas storage tank is determined based on a thermodynamic gas isothermal change model and converges within a defined numerical boundary under rated operating parameters. Specifically, this matching relationship is defined by the following selection formula:

[0075] V N2 =(P1*△ V*Z1T1*Z2T2) / [Z3T3*(P*Z2T2-P1*Z1T1)];

[0076] Among them, V N2 For the physical volume of an independent gas storage tank, △ V The effective liquid phase volume change in the liquid phase region within the high-pressure hot water storage tank during a single energy storage and release cycle is denoted as P1, where P1 is the rated operating pressure of the high-pressure hot water storage tank, and P is the design maximum pressure of the independent gas storage tank. T1 is the temperature at the highest pressure of the independent storage tank, and Z1 is the compressibility factor of nitrogen at the highest pressure of the independent storage tank. T2 is the temperature at the lowest pressure of the independent storage tank, and Z2 is the compressibility factor of nitrogen at the lowest pressure of the independent storage tank. T3 is the temperature of the high-pressure hot water storage tank, and Z3 is the compressibility factor of nitrogen within the high-pressure hot water storage tank.

[0077] Furthermore, after determining the physical volume of the independent gas storage tank using the above selection formula, since the medium inside the independent gas storage tank is a pure gas phase, there is no need to configure water-side anti-corrosion lining, thermal stratification control structure, or stress-reinforcing components for large-diameter inlet and outlet water pipes. Therefore, its construction cost per unit pressure volume is lower than that of a water container of equal volume. After reasonably configuring the pressure difference between the design maximum pressure and the rated operating pressure, the overall hardware investment of the system can be lower than the total cost of configuring an equivalent high-pressure chilled water container in a traditional symmetrical architecture.

[0078] Optionally, the gas phase space inside the high-pressure hot water storage tank retains a minimum safe gas phase volume to prevent liquid from entering the gas pipeline network at the highest operating liquid level.

[0079] This embodiment establishes the physical isolation safety boundary of the system under full-load energy storage conditions. As high-pressure hot water is continuously injected, the liquid level in the liquid phase region of the high-pressure hot water storage tank continues to rise, and the gas phase space is gradually compressed. The ratio of the gas phase space volume to the total volume of the high-pressure hot water storage tank is defined as the gas phase space ratio. To prevent high-temperature water from overflowing and entering the gas pipeline network connected to its top during sudden changes in system load, which could cause liquid hammer failure in subsequent pressurization equipment, the gas phase space ratio must be maintained above the safety lower limit.

[0080] Furthermore, the minimum safe gas phase volume is determined by a preset lower limit of the gas phase space ratio. In a typical deployment environment, this preset lower limit can be set to 3-5% of the total volume of the high-pressure hot water storage tank. This volume retention range covers the amplitude of thermal expansion disturbance of the liquid surface under full-load water inflow conditions and the momentum tumbling depth generated by fluid influx.

[0081] In some alternative implementations, the proportion of the gas phase space is also limited by an operating upper limit. This operating upper limit corresponds to the minimum operating liquid level of the system, used to prevent cavitation damage to the hot water circulation pump caused by the evacuation of the high-temperature fluid at the bottom. When the system sensors detect that the liquid level in the liquid phase zone rises to the elevation threshold corresponding to the minimum safe gas phase volume, the control unit triggers a high-level alarm interlock, cutting off the injection path of external cold water to ensure the safe isolation of the high and low pressure dual-state circulation and the integrity of the equipment.

[0082] Accordingly, by removing the pressure requirements of the cryogenic fluid, an asymmetric physical topology was constructed, consisting of atmospheric pressure cold water, high pressure hot water, and an independent protective gas, and the volume boundary grouping parameters were matched. This approach reduces the heavy manufacturing limitations of large-volume cryogenic high-pressure vessels, thereby reducing the overall investment in pressure-bearing materials and hardware for the thermal storage system.

[0083] Example 3: This example further details the control process of the gas pressurization device in the pressurized hot water partial pressure storage system.

[0084] In one possible implementation, the initial protective gas is pressurized using a gas pressurization device, such as... Figure 1 As shown, the operating parameters of the gas pressurization device are determined through the following steps 301-305:

[0085] Step 301: Obtain the current liquid level change rate of the high-pressure hot water storage tank, obtain the current pressure value of the independent gas storage tank in real time, and obtain the real-time pressure deviation of the independent gas storage tank based on the difference between the pre-configured target pressure setting value of the independent gas storage tank and the current pressure value.

[0086] As an optional implementation, during the determination of the operating parameters of the gas pressurization device, the control unit collects the height of the fluid surface in real time using a liquid level sensor deployed on the high-pressure hot water storage tank, and calculates the current liquid level change rate using a differential method within a preset sampling time interval. The current liquid level change rate reflects the speed at which the liquid level rises due to the influx of high-temperature fluid during the energy storage phase, and its change pattern is positively correlated with the variable operating condition scheduling requirements of the compressed air energy storage system. Simultaneously, the control unit obtains the actual pressure value inside the independent gas storage tank in real time using a pressure sensor, and subtracts the pre-configured target pressure value from the actual pressure value to calculate the real-time pressure deviation of the independent gas storage tank.

[0087] The current rate of change of liquid level is expressed as: L dot (t)=(L(t)-L(t-△ t )) / △ t ;

[0088] Where L(t) is the liquid level value at the current moment, and L(t-Δ) t) represents the liquid level value at the previous sampling time, △ t This is the preset sampling time interval.

[0089] Step 302: Calculate the feedforward rotation speed command of the gas booster device based on the current liquid level change rate.

[0090] Accordingly, the control unit uses the acquired current liquid level change rate as the core feedforward control data to predict in advance the gas overflow rate caused by the reduction in volume of the gas phase space at the top of the high-pressure hot water storage tank. This type of feedforward mechanism avoids the lag drawbacks of traditional feedback regulation that relies solely on pressure deviation, allowing the gas pressurization device to adjust its motor speed in advance before the internal gas pressure exceeds the limit. Specifically, the feedforward control quantity is determined by the cavity geometry and the liquid level rise rate, thus forming coordinated control across the liquid and gas path subsystems.

[0091] Step 303: Perform proportional-integral regulation calculation based on the real-time pressure deviation to obtain the feedback speed correction of the gas booster device.

[0092] Specifically, the control unit calculates the feedback speed correction using the following discretized proportional-integral formula:

[0093] n fb (k)=Kp*e(k)+Ki*Σ j=0 k [e(j)*△ t ];

[0094] Where, n fb (k) represents the feedback speed correction in the kth sampling period, e(k) represents the real-time pressure deviation in the kth sampling period, Kp represents the proportional gain, Ki represents the integral gain, and Δ t The sampling time interval is denoted as Kp. The proportional gain Kp and integral gain Ki can be determined by those skilled in the art through engineering tuning methods.

[0095] Furthermore, while introducing feedforward control, the system retains a feedback loop to reduce modeling errors and residual deviations caused by pipeline environmental disturbances. The control unit inputs the calculated real-time pressure deviation into a conventional proportional-integral (PI) control algorithm. Through proportional amplification and time-domain integral accumulation of the deviation, the final output is the feedback speed correction for the gas booster device. During operation, if the real-time pressure of the independent gas storage tank deviates from the set target, the feedback speed correction will dynamically increase or decrease, providing closed-loop correction to the feedforward control, which helps ensure the final pressure of the gas storage system converges smoothly.

[0096] Step 304: The feedforward speed command and the feedback speed correction are superimposed and fused, and the fused value is truncated using the pre-configured allowable speed boundary of the gas booster device to obtain the target operating speed of the gas booster device.

[0097] In this embodiment, to balance rapid response to load changes with steady-state accuracy of system operation, the control unit algebraically sums the feedforward speed command and feedback speed correction obtained from the previous steps, thus achieving the superposition and fusion of control signals. Based on this, to ensure the mechanical safety of the gas booster device and prevent motor overspeed or operation in the low-frequency surge range, the control unit loads a pre-configured permissible speed boundary for the gas booster device and performs truncation and amplitude limiting control on the fused value, ultimately generating the target operating speed of the gas booster device.

[0098] Specifically, the numerical expression for the fused rotational speed is: n cmd (t)=n ff (t)+n fb (t);

[0099] Where, n ff (t) represents the feedforward speed command, n fb (t) represents the feedback speed correction amount.

[0100] After obtaining the merged speed values, the control unit performs a truncation determination based on pre-configured allowable speed boundaries. These allowable speed boundaries include the maximum allowable speed and the minimum stable speed. The specific determination criteria are as follows:

[0101] If n cmd (t)≥n max Then the target operating speed is n. max ;

[0102] If n cmd (t)≤n min Then the target operating speed is n. min ;

[0103] When n cmd (t) is in n min With n max When n is between, the target operating speed is taken as n. cmd (t) itself;

[0104] Where, n max For the maximum permissible speed, n min This is the minimum stable speed.

[0105] Step 305: Drive the gas pressurization device in real time using the target operating speed.

[0106] Furthermore, after determining the target operating speed, the control unit converts the digital signal into a corresponding frequency control command and outputs it to the variable frequency drive. The variable frequency drive adjusts the frequency of the current supplied to the booster motor to match its mechanical speed with the target operating speed. Through this variable frequency drive process, the booster can adaptively follow the internal gas phase changes of the high-pressure hot water storage tank to continuously adjust exhaust power consumption, reducing wear and tear from frequent start-ups and shutdowns of power plant equipment.

[0107] According to one aspect of this application, the feedforward rotational speed command of the gas pressurization device is calculated based on the current rate of liquid level change, such as... Figure 2 As shown, this specifically includes steps 306-310:

[0108] Step 306: Obtain the internal cross-sectional area of ​​the high-pressure hot water storage tank, as well as the real-time gas phase operating pressure and real-time gas phase temperature in the gas phase space.

[0109] In some embodiments, as a deep physical mechanism supporting the feedforward control logic, the control unit loads the static geometric parameters of the internal cross-sectional area of ​​the high-pressure hot water storage tank, which are pre-stored in the memory. Simultaneously, using a pressure transmitter and temperature sensor arranged on the top of the tank, the real-time gas phase operating pressure and temperature within the gas phase space are acquired and received in real time, serving as the basic boundary input for subsequent gas phase mass flow conversion calculations.

[0110] Step 307: Multiply the internal cross-sectional area by the current liquid level change rate to obtain the initial protective gas discharge volume rate.

[0111] Furthermore, since the high-temperature hot water inside the high-pressure hot water storage tank is an incompressible fluid, the volume displacement caused by the rise in its liquid level is equivalent to the volume reduction of the gas phase space. The control unit multiplies the internal cross-sectional area by the previously calculated current liquid level change rate to calculate the initial protective gas discharge volume rate, which is expressed as: V gas,out (t)=A tank *L dot (t);

[0112] Among them, A tank L is the internal cross-sectional area of ​​the high-pressure hot water storage tank. dot (t) represents the current rate of change of liquid level.

[0113] Step 308: Based on the real-time gas phase operating pressure and real-time gas phase temperature, the gas discharge volume rate is converted to mass density using the gas state equation to obtain the minimum mass flow rate required to maintain the exhaust.

[0114] Correspondingly, since the protective gas is compressible under high pressure conditions of 2.7~10.0 MPa, its volumetric rate cannot accurately reflect the actual exhaust load of the booster device under different temperatures and pressures. Based on the law of conservation of mass, the control unit introduces an ideal gas law that includes the compressibility factor. It calculates the current real-time density of the protective gas by dividing the product of the real-time gas phase operating pressure and the molar mass of the protective gas by the product of the compressibility factor, the universal gas constant, and the real-time gas phase temperature. Furthermore, it multiplies this real-time density by the aforementioned gas exhaust volumetric rate to finally calculate the minimum mass flow rate required to maintain a constant internal pressure in the high-pressure hot water storage tank.

[0115] The required minimum mass flow rate is expressed as: m comp,min (t)=(P HWT *M N2 ) / (Z*R*T gas )*V gas,out (t);

[0116] Among them, P HWT The operating pressure is collected in real time within the vapor space of the high-pressure hot water storage tank. During normal system operation, its value is maintained at the rated operating pressure of the high-pressure hot water storage tank. M N2 To protect the molar mass of the gas, Z is the compressibility factor, R is the universal gas constant, and T is... gas V represents the real-time gas phase temperature. gas,out (t) represents the gas discharge volume rate.

[0117] In this embodiment, nitrogen is selected as the protective gas, with a corresponding molar mass M. N2 Configured as 28*10 -3 The general gas constant R is configured as 8.314 joules per mole (kg / mol). Optionally, due to deviations in actual gas behavior of nitrogen under high pressure and high temperature mixing, the compressibility factor Z is determined based on practical experience within the engineering scope, with its value limited to between 0.97 and 1.01. In simplified calculations, to improve the feedforward regulation response rate, the compressibility factor Z can be approximated to 1.0. The resulting flow calculation error, after verification, is less than 3%, meeting the engineering accuracy requirements for pressure stabilization control of the thermal storage system.

[0118] Step 309: Obtain the rated speed and rated mass flow rate of the pre-configured gas booster device.

[0119] Simultaneously, the control unit loads the static rated parameters of the gas booster device stored in the local data configuration table. Among them, the rated speed and rated mass flow rate represent the mechanical operating reference of the gas booster device under standard design conditions, and are used as a proportional scale to convert the mass flow rate into the specific inverter drive frequency.

[0120] Step 310: Based on the ratio between the required minimum mass flow rate and the rated mass flow rate, the rated speed is proportionally converted to obtain the feedforward speed command.

[0121] Furthermore, the control unit calculates the dimensionless ratio between the required minimum mass flow rate and the rated mass flow rate obtained above, and performs a multiplication operation between this ratio and the rated speed, thus completing the proportional conversion from physical flow rate to the desired motor speed, and finally outputs the feedforward speed command.

[0122] The expression for the feedforward speed command is: n ff (t)=n0*m comp,min (t) / m comp,rated ;

[0123] Where n0 is the rated speed of the gas booster device, m comp,min (t) represents the required minimum mass flow rate, m comp,rated This refers to the rated mass flow rate of the gas booster device.

[0124] In other embodiments, dynamic tracking of the outlet pressure is also included when determining the operating parameters of the gas booster device:

[0125] Optionally, the current operating pressure inside an independent gas storage tank can be obtained in real time.

[0126] Accordingly, in the adjustment of the operating boundaries of the gas pressurization device, in addition to controlling the exhaust speed to match the volume expansion rate, it is also necessary to dynamically monitor the back pressure boundary of its exhaust channel. The control unit collects and receives the current operating pressure inside the independent gas storage tank in real time through a pressure sensor installed at the outlet of the independent gas storage tank pipeline, which is used as a real-time feedback reference for dynamically calculating the pressurization head setpoint.

[0127] Optionally, the outlet pressure setting value of the gas booster device can be dynamically determined based on the current operating pressure and by adding a preset pipeline pressure loss safety margin.

[0128] Specifically, because the gas in the independent gas storage tank is dynamically loaded during different energy storage periods, its internal pressure fluctuates continuously. If the outlet exhaust pressure of the gas booster device remains constant, an increase in the pressure of the independent gas storage tank can cause the booster device to experience backflow or surge failure due to pressure buildup. The control unit performs an addition calculation on the received current operating pressure and the preset pipeline pressure loss safety margin, using this as the upper limit of the outlet pressure to dynamically determine the outlet pressure setpoint of the gas booster device.

[0129] The expression for the outlet pressure setpoint of the gas booster is: P comp,out (t)=P N2,current (t)+δ;

[0130] Among them, P N2,current (t) represents the current operating pressure inside the independent gas storage tank, and δ represents the preset pipeline pressure loss safety margin.

[0131] In this embodiment, the preset pipeline pressure loss safety margin is set within a reasonable range of 0.05 to 0.15 MPa. By configuring a safety margin within this range, it is beneficial to ensure that the gas discharged from the pressurization device has sufficient kinetic energy to overcome the friction loss along the one-way shut-off valve and connecting pipeline, and is injected into the independent gas storage tank.

[0132] Optionally, the actual exhaust pressure of the control gas booster device tracks the outlet pressure setpoint.

[0133] After determining the outlet pressure setpoint, the control unit sends this target pressure value to the outlet pressure regulating valve of the booster unit or as an adaptive tracking target for the exhaust pressure of the variable frequency impeller guide vanes. Through closed-loop servo adjustment of the control system, the actual exhaust pressure is made slightly higher than the current operating pressure inside the independent gas storage tank by a safety margin for pressure loss. This dynamic tracking design reduces excessive energy loss caused by constant high-pressure exhaust and achieves adaptive energy efficiency optimization of the system's exhaust process.

[0134] In some alternative implementations, when the current energy storage switching condition is in its initial brief phase, if the previous energy release cycle has exhausted the protective gas supply in the independent gas storage tank, causing its pressure to drop to near the working pressure of the high-pressure hot water storage tank, the pressure difference between the two sides approaches zero. Under this extreme condition, the mechanical pressure generated by the rise in the high-pressure hot water storage tank level can overcome the low friction resistance of the pipeline, driving the initial protective gas through the check valve into the independent gas storage tank for storage. At this time, the control unit determines that a simplified self-starting mode has been entered, temporarily placing the gas booster device in bypass standby mode until the pressure in the independent gas storage tank rises due to the gas inflow and generates reverse resistance. Then, it automatically engages and controls the gas booster device to perform the aforementioned variable frequency feedforward feedback operation. This alternative scheme can reduce the equipment power consumption during the low-pressure-difference start-up phase and improve the overall operational flexibility.

[0135] Optionally, the gas connection between the hot and cold fluids is physically severed, and a feedforward-feedback frequency conversion algorithm based on the liquid level displacement rate is introduced. This approach enables the system to respond in advance and compensate for the overflow momentum of the gas before the liquid surface volume contracts. Unlike the lag in regulation of traditional pure back pressure feedback, this method constrains the back pressure deviation during the alternation of charging and discharging heat within a small dynamic dead zone, avoiding coupled oscillations caused by sudden changes in gas density due to temperature differences.

[0136] Example 4: This example further details two parallel implementation methods for flash evaporation protection during the energy release stage.

[0137] In one possible implementation, a pressure reduction protection structure and operation method based on temperature hard boundary interlocking are provided. Optionally, the pressure reducing component includes a single-stage pressure reducing valve and a bypass reflux unit. The single-stage pressure reducing valve is connected in series on the hot water delivery pipeline and is located between the air heater and the atmospheric pressure cold water storage tank. The bypass reflux unit includes a bypass pipeline and a bypass valve installed on the bypass pipeline. The upstream end of the bypass pipeline is connected to the hot water delivery pipeline between the air heater and the single-stage pressure reducing valve, and the downstream end is connected to the internal cavity of the high-pressure hot water storage tank.

[0138] This embodiment provides the anti-flash evaporation hardware protection topology in the main scheme. Under normal energy release design conditions, since the design pressure of the atmospheric pressure cold water storage tank is approximately the local atmospheric pressure, if the temperature of the fluid entering the atmospheric pressure cold water storage tank is higher than the saturation boiling point of water at atmospheric pressure, the water will undergo a flash vaporization phase change, leading to two-phase flow impact erosion in the pipeline and the risk of overpressure damage to the atmospheric pressure vessel. To avoid the above physical damage, the main circuit of the system retains only a single-stage pressure reducing valve as a conventional pressure drop channel, while a bypass pipeline is connected in parallel at the valve upstream node. By adding a bypass valve to the bypass pipeline, the system constructs a pressure return channel independent of the pressure reduction and discharge path, so that under unsteady heat exchange conditions, the insufficiently cooled fluid source can be guided back to its source, preventing high-temperature fluid from entering the atmospheric pressure region.

[0139] According to one aspect of this application, prior to the step of depressurizing the returned water after heat release using a pressure-reducing assembly, such as Figure 3 As shown, it also includes flash evaporation prevention safety control steps 401-404:

[0140] Step 401: Obtain the current return water temperature after heat release in real time.

[0141] In some embodiments, during the dynamic monitoring of the energy release process, the control unit utilizes a temperature sensing node located between the downstream outlet side of the air heater and the inlet side of the single-stage pressure reducing valve to collect the physical temperature scalar of the fluid flowing through the pipe section in real time, and uses it as the current return water temperature after heat release. This temperature parameter characterizes the residual heat state of the high-pressure hot water after heat exchange with compressed air inside the air heater, and is a key pre-input variable for determining whether the subsequent pressure reduction process will induce a flash phase change.

[0142] Step 402: Obtain the pre-configured temperature safety threshold and compare the current return water temperature with the temperature safety threshold.

[0143] Optionally, the control unit reads the temperature safety threshold pre-configured during the offline design phase from the local register. The temperature safety threshold is set to a temperature limit below the saturation boiling point of water under normal ambient pressure. To maintain the accuracy of system measurement and control and the safety margin for heat transfer fluctuations, the temperature safety threshold is typically set to 90°C. Furthermore, within each monitoring calculation cycle, the control unit continuously compares the real-time collected current return water temperature with the temperature safety threshold to assess the thermodynamic safety of the current fluid state.

[0144] Step 403: When the current return water temperature is greater than the temperature safety threshold, the interlock protection mechanism is triggered. Specifically, the operation of depressurizing the return water after heat release using the pressure reducing component is stopped, and the preset bypass return path on the hot water delivery pipeline is opened to guide the return water after heat release back to the liquid phase zone of the high-pressure hot water storage tank for circulation.

[0145] Furthermore, during the initial unsteady-state establishment phase of energy release or under abnormal conditions such as a sudden drop in air-side load, the high-pressure hot water may sometimes be unable to release its heat within the air heater, resulting in a higher fluid temperature at the heat exchange outlet. Once the comparison calculation determines that the current return water temperature exceeds the defined temperature safety threshold, the control unit sends a strong-level command to cut off the execution coil of the single-stage pressure reducing valve, shutting off the high-pressure discharge main line to the atmospheric pressure cold water storage tank, and ceasing the operation of depressurizing the returned water after heat release using the pressure reducing component. Simultaneously, the control unit commands the bypass valve to open the preset bypass return path. Since the bypass return path connects to the internal cavity of the high-pressure hot water storage tank, the returned water after heat release can return to the liquid phase region of the high-pressure hot water storage tank while maintaining the original high-pressure state to continue participating in the thermodynamic cycle.

[0146] Step 404: Continue performing the depressurization treatment on the heat-released return water until the current return water temperature is detected to drop below the temperature safety threshold.

[0147] Correspondingly, as the energy release process continues, the temperature gradient inside the air heater gradually establishes and enters a heat exchange steady state, allowing the high-pressure hot water flowing through the component to be sufficiently cooled. When the control unit continuously monitors and determines that the current return water temperature has steadily fallen back to the safe temperature threshold and below its set hysteresis dead zone, it indicates that the fluid has met the physical conditions to be depressurized to atmospheric pressure without flash evaporation. At this point, the control unit cancels the interlocking signal for the abnormal operating condition, instructs the bypass valve to close and the single-stage pressure reducing valve to reopen, causing the system fluid to re-enter the normal energy release one-way pressure relief and injection process.

[0148] As an alternative to the above solution, this embodiment also provides another pressure-reducing component structure and operation method based on two-stage separation, which provides redundant physical protection with flash steam latent heat recovery capability under extreme insufficient heat exchange conditions. The specific difference lies in the use of a hardware cascade structure with vapor-liquid separation function. The remaining high and low pressure storage tanks and gas pipeline network structures are the same as those in the previous embodiment, and can be referred to the foregoing description, which will not be repeated here.

[0149] Optionally, the alternative embodiment includes: a pressure reducing assembly comprising a first-stage pressure reducing valve, an intermediate flash tank, and a second-stage pressure reducing valve connected in series along the fluid flow direction; the intermediate flash tank having an internal cavity for vapor-liquid separation; the liquid phase outlet at the bottom of the intermediate flash tank being connected to the inlet of the second-stage pressure reducing valve; the pressure reducing assembly further includes a preheating heat exchanger; the vapor phase outlet at the top of the intermediate flash tank being connected to the hot-side inlet of the preheating heat exchanger via a steam pipeline; the hot-side outlet of the preheating heat exchanger being connected to an atmospheric pressure cold water storage tank; and the cold side of the preheating heat exchanger being connected in series on a cold water delivery pipeline between the atmospheric pressure cold water storage tank and the main heat exchanger.

[0150] Furthermore, this hardware design decomposes the single-stage steep pressure drop process into a two-stage step pressure reduction. The first-stage pressure reducing valve acts as a preliminary throttling and pressure reduction component, reducing the high-pressure hot water to an intermediate pressure platform between high pressure and atmospheric pressure. The intermediate flash tank, as a pressure vessel with expansion space, receives the vapor-liquid two-phase mixture generated after the first pressure reduction, and utilizes gravity settling and cyclone separation principles to physically separate the droplets and steam within the internal cavity. The preheating heat exchanger is located on the steam loop side, collecting the flash steam and transferring its latent heat of condensation to the atmospheric pressure chilled water to be heated in the chilled water delivery pipeline, thus realizing the cascade recovery and reuse of usable energy within the system.

[0151] As an alternative implementation, in the step of depressurizing the heat-released return water using a pressure-reducing assembly, a vapor-liquid separation depressurization logic is specifically adopted, including:

[0152] Optionally, the pressure of the return water after heat release can be reduced once using a first-stage pressure reducing valve.

[0153] In some embodiments, before the fluid enters the atmospheric pressure region, the control unit instructs the first-stage pressure reducing valve to open to the calculated opening degree, forcing the exothermic return water, which is under high pressure and high temperature, to experience a pressure drop through the valve core throttling orifice. Through this pressure reduction operation, the static pressure of the fluid is rapidly reduced to the set intermediate flash pressure scale, causing some sensible heat to be converted into latent heat, inducing spontaneous boiling and partial vaporization of the water.

[0154] Optionally, the fluid after initial depressurization can be introduced into an intermediate flash tank for vapor-liquid separation.

[0155] Correspondingly, the mixed fluid containing numerous tiny bubbles and droplets, formed after throttling and depressurization, is then guided into the intermediate flash tank. Within the abruptly expanded internal cavity, the fluid velocity decreases. Heavier, pure liquid water droplets naturally converge downwards to the liquid accumulation zone at the bottom of the tank under the influence of gravity, while lighter flash vapor rises and accumulates in the gas phase convergence zone at the top of the tank, achieving efficient separation of the vapor and liquid phases independently without external power. During this physical separation stage, the control unit uses a conventional thermodynamic equation based on the fluid enthalpy drop ratio to perform background calculations and matching of the vaporization rate of the intermediate flash tank; this property state assessment algorithm will not be further elaborated here.

[0156] Optionally, the separated liquid phase fluid is depressurized again by a second-stage pressure reducing valve and then sent back to the atmospheric pressure cold water storage tank as atmospheric pressure low-temperature water.

[0157] Correspondingly, the liquid fluid collected at the bottom of the intermediate flash tank has already cooled to the saturation temperature corresponding to the intermediate pressure as the intermediate pressure is established. Further, this liquid fluid is discharged into the second-stage pressure-reducing valve for final secondary pressure reduction and closure. Since the initial temperature at this stage is already lower than the original return water temperature after heat release, the amount of secondary flash evaporation generated by the secondary pressure reduction to atmospheric pressure is extremely small or even negligible. The safe liquid fluid after pressure reduction is then transported back to the atmospheric pressure cold water storage tank for temporary storage as atmospheric pressure cryogenic water.

[0158] Optionally, the separated vapor phase fluid is introduced into the hot side of the preheating heat exchanger. After condensation and heat release in the preheating heat exchanger, the vapor phase fluid forms condensate and flows into the atmospheric pressure cold water storage tank. The cold side of the preheating heat exchanger receives the atmospheric pressure cold water output from the atmospheric pressure cold water storage tank and uses the condensation heat of the vapor phase fluid to preheat the atmospheric pressure cold water to obtain preheated cold water, which is then output to the main heat exchanger.

[0159] In certain application scenarios of this application, the vapor-phase fluid drawn from the top of the intermediate flash tank carries the latent heat of vaporization released due to pressure drop. This high-temperature steam is introduced into the hot-side channel of the preheating heat exchanger through a steam pipeline, where it exchanges wall heat with atmospheric pressure chilled water flowing in the cold-side channel. After releasing heat and condensing, the steam becomes liquid condensate and is incorporated into the atmospheric pressure water storage cavity, while the atmospheric pressure chilled water, having absorbed the latent heat of vaporization, receives initial temperature rise and preheating. This operation process handles the steam generated by pressure reduction flash evaporation and uses this waste heat in a closed loop as the basic heat source for chilled water temperature rise during the energy storage stage, improving the overall thermodynamic efficiency of the entire thermal energy storage system.

[0160] Example 5: This example further details the gas-liquid timing coordinated control during the transition between the energy storage and energy release stages of the system.

[0161] In one possible implementation, during the switch from the energy storage phase to the energy release phase, the disturbance-free switching control is performed according to the following timing sequence: Figure 4 As shown, the specific steps include 501-505:

[0162] Step 501: Gradually reduce the operating frequency of the cold water booster pump until it stops, and simultaneously control the gas booster device to slow down to a stop state.

[0163] Specifically, in the initial stage of the operating condition switch, the system is in a pre-shutdown buffer period before ceasing energy storage. The control unit sends a ramp-down command to the variable frequency drive, controlling the chilled water booster pump located on the chilled water delivery pipeline to perform a uniform deceleration operation. The deceleration rate can be set to no more than 20% per minute to avoid sudden changes in fluid momentum causing water hammer effects within the pipeline network and damaging the pressure boundary. Simultaneously, the control unit issues a speed reduction command to the gas booster device, causing its exhaust volume to gradually decrease to the lowest stable speed threshold, and then cuts off the main motor power to complete the physical shutdown. Through the coordinated buffer shutdown of the liquid and gas power equipment, the fluid kinetic energy and pressure gradient inside the system are released smoothly, preventing the mechanical impact of transient pressure differences on the heat exchanger and tank interface.

[0164] Step 502: Close the first gas path between the high-pressure hot water storage tank and the independent gas storage tank.

[0165] Accordingly, after confirming the shutdown of the power equipment, the control unit enters the gas path blocking phase. The system sends a shutdown control level to the shut-off valve located in the first gas path, driving the valve actuator to perform a full-close action. This blocking operation cuts off the one-way exhaust channel between the gas phase space at the top of the high-pressure hot water storage tank and the independent gas storage tank. Since the independent gas storage tank accumulates protective gas at the highest design pressure at the end of the energy storage cycle, closing the recovery pipeline can physically prevent the high-pressure protective gas from flowing back after the gas pressurization device stops, maintaining the pressure barrier established between the two tanks.

[0166] Step 503: Open the gas supply regulating valve to the preset initial opening value and monitor the internal operating pressure of the high-pressure hot water storage tank. When the deviation between the internal operating pressure and the pre-configured rated operating pressure falls within the preset allowable deviation range, confirm that the high-pressure hot water storage tank has reached the initial pressure stabilization state.

[0167] Furthermore, after the gas path is blocked, the system performs a pre-pressurization operation on the energy release gas path. The control unit commands the gas supply regulating valve located on the second gas path to open. To prevent a large influx of high-pressure fluid from the independent gas storage tank into the high-pressure hot water storage tank, which could cause pressure overshoot or trigger the safety valve, the opening of the gas supply regulating valve uses amplitude limiting control logic. Its control signal is limited to a preset initial opening value range, for example, setting the initial opening to 5%. As the high-pressure protective gas is slowly injected through throttling, the pressure transmitter located on top of the high-pressure hot water storage tank continuously collects and feeds back the internal pressure scalar. The control unit compares this pressure scalar with the rated operating pressure until it determines that the deviation between the two falls within the set dead zone range, confirming that the system has established and maintained an initial pressure stabilization state, providing a back pressure basis to prevent cavitation for the subsequent start-up of the hot water circulation pump.

[0168] Step 504: Start the hot water circulation pump and activate the pressure reducing component to establish a complete energy release fluid channel.

[0169] Optionally, provided that the back pressure in the gas path is stably established, the control unit transitions to the energy release liquid path activation stage. The system sends a variable frequency start command to the hot water circulation pump, gradually increasing the motor speed according to a preset frequency and slope, continuously extracting high-pressure hot water from the liquid phase zone of the high-pressure hot water storage tank and pumping it to the air heater for heat exchange. After the hot water circulation pump reaches a stable output state, the control unit synchronously commands the pressure reducing component located at the end of the pipeline to activate, allowing the returned water after heat release to be depressurized and flow back to the atmospheric pressure cold water storage tank. At this point, the complete water circulation chain from high-pressure hot water extraction, air heating heat release to atmospheric pressure cold water recovery is established, and the system smoothly transitions to full-load energy release operation.

[0170] Step 505, wherein, throughout the entire operating condition switching and system operation cycle, the first air circuit and the air supply regulating valve are simultaneously in the open state.

[0171] Furthermore, this embodiment establishes a rigid gas path anti-collision interlock mechanism throughout the system's entire lifecycle. The control unit is configured with a state machine mutual exclusion decision matrix in its underlying control logic, cross-interlocking the state feedback signal of the first gas path shut-off valve with the drive circuit of the gas supply regulating valve. If a tendency for both to be simultaneously open is detected, the underlying logic will unconditionally reject the current control command and trigger a safety shutdown. This interlock mechanism is used when the first and second gas paths are connected in parallel between two containers with a large pressure difference. If both gas paths are simultaneously open, the high-pressure protective gas in the independent gas storage tank will bypass the system through the parallel pipeline without any heat storage buffering process, resulting in the loss of effective usable energy. The high-speed airflow generated by the short circuit will also exert a large torque on the reverse impeller of the gas pressurization device.

[0172] In some alternative implementations, when the system reverses its transition from the energy release phase to the energy storage phase, the control unit invokes a state transition operation flow with the reverse timing described above. Specifically, the system first performs a ramp-down shutdown and shut-off of the energy release hot water circulation pump and the gas supply regulating valve. After monitoring the system fluid state to ensure stability, the first gas path is then opened, and the cold water booster pump and gas pressurization device are started. The reverse switching operation is subject to lockout rules to ensure the thermodynamic safety and mechanical stability of the asymmetric thermal storage system during multimodal cycle transitions.

[0173] Example 6: This example further details the auxiliary operation, maintenance compensation, and horizontal architecture expansion of the pressurized hot water partial pressure thermal storage system throughout its entire life cycle.

[0174] In one possible implementation, prior to the initial energy storage phase, an initial pressurization and storage build-up step for cold start-up of the system is included, specifically comprising the following operational procedures:

[0175] Optionally, an external initial gas source can be connected, and gas can be continuously injected into the gas phase space of the high-pressure hot water storage tank through the external initial gas source until the pressure inside the high-pressure hot water storage tank reaches the rated operating pressure.

[0176] As an optional implementation, during the cold start-up phase after the system's initial physical installation and preparation for grid connection and commissioning, both the high-pressure hot water storage tank and the independent gas storage tank are at atmospheric pressure, with no working medium in the liquid phase. The control unit opens the main inlet valve connected to the external gas supply network, continuously injecting high-pressure pure gas as the initial working medium into the system's internal cavity. During this injection process, the control unit continuously collects the internal pressure scalar of the container until it detects that the internal pressure of the high-pressure hot water storage tank has risen and stabilized at the rated operating pressure. At this point, the container is in a state of full gas with no fluid.

[0177] Optionally, a cold water booster pump is started to inject high-pressure hot water that has undergone heat exchange, while the gas squeezed out by the rising liquid level is continuously transferred to an independent gas storage tank through a gas booster device.

[0178] Accordingly, after establishing the initial back pressure, the control unit instructs the water circulation system to start. The cold water booster pump pressurizes the atmospheric pressure fluid and sends it to the heat exchanger to obtain heat energy, then pumps it into the bottom of the high-pressure hot water storage tank. As the liquid level in the liquid phase zone gradually rises from zero, the initial protective gas that originally filled the container is displaced by the fluid volume and discharged into the first gas path. The control unit simultaneously activates the gas pressurization device to pressurize the gas that overflows due to gas-liquid displacement and continuously delivers it to the high-pressure gas storage chamber of the independent gas storage tank for accumulation.

[0179] Optionally, when the liquid phase zone inside the high-pressure hot water storage tank reaches the designed maximum liquid level, the system is initially pressurized, the external initial gas source is shut off, and the system is put into normal operation standby mode.

[0180] In some embodiments, the liquid-gas replacement process continues, with the gas level and pressure inside the independent gas storage tank rising synchronously. When the liquid level in the high-pressure hot water storage tank reaches the pre-designed maximum physical elevation limit, the control unit determines that the working fluid reserve and protective gas reserve inside the system have met all the physical requirements for a single cycle. At this point, the system closes the external gas source interface, cuts off the water filling command, establishes the initial momentum and mass inventory benchmark of the system, and controls all fluid machinery to enter the normal closed-loop standby phase.

[0181] In one possible implementation, during the initial pressurization and subsequent long-term static condition between the energy storage and release phases, the system performs static pressure maintenance including:

[0182] Optionally, the internal operating pressure of the high-pressure hot water storage tank can be continuously monitored.

[0183] Correspondingly, during the standby period when the system is not performing thermal energy throughput tasks, the internal fluid will experience slow heat dissipation due to the temperature gradient of the external environment of the storage tank. During this period, the control unit keeps the data acquisition channel open, continuously acquiring the real-time pressure signal transmitted back from the pressure transmitter located in the gas phase space, in order to capture the pressure decay trend caused by slight changes in thermodynamic state.

[0184] Optionally, when the internal operating pressure falls below the preset lower limit for static maintenance due to heat loss during static operation, the gas supply regulating valve is opened to perform a small pressure replenishment operation.

[0185] Furthermore, based on the ideal gas isochoric change law, the decrease in the gas-phase interface temperature inside the high-pressure hot water storage tank will cause a proportional and synchronous decrease in the static pressure scalar applied by the sealing gas itself. When the control unit detects that this physical pressure drop exceeds the preset lower limit of static maintenance, the system sends a small-opening action pulse to the gas supply regulating valve in the second gas line. The high-pressure medium stored in the independent gas storage tank passively permeates into the high-pressure hot water storage tank through this micro-opening channel.

[0186] Optionally, when the internal operating pressure returns to the pre-configured rated operating pressure, the gas supply regulating valve is closed to maintain stable system pressure during the resting period.

[0187] Simultaneously, with the influx of supplemental gas, the pressure inside the high-pressure hot water storage tank is raised again. Once the pressure feedback curve reaches the target setpoint baseline, the control unit cancels the drive pulse, and the gas supply regulating valve resets to the fully closed shut-off state. This passive compensation mechanism can maintain the micro-dynamic constant pressure of the container during the resting period, preventing fluid cavitation of the circulation pump during the next startup due to pressure collapse.

[0188] In one possible implementation, to address the unavoidable physical leakage of the pipeline network during long-term dynamic circulation, the system also includes compensation for the loss of protective gas after the energy storage phase ends.

[0189] Optionally, the current endpoint pressure within a separate gas storage tank can be obtained.

[0190] Accordingly, at the end of each complete fluid storage cycle, the individual gas storage tank should theoretically contain all the usable gas that has been squeezed out of the system. At this timing node, the control unit extracts the static data fed back by the pressure sensor installed on the individual gas storage tank and uses it as the current endpoint pressure for evaluating the overall airtightness of the system and the total gas inventory.

[0191] Optionally, the design maximum pressure of a pre-configured independent gas storage tank is obtained, and the lower limit threshold of the allowable pressure is calculated based on a preset pressure loss ratio.

[0192] Specifically, the control unit reads the maximum design pressure limit value established during the factory design phase from the storage array, and calls up the preset pressure loss ratio based on the system's tolerance for pressure drop. After multiplying this loss ratio by the maximum design pressure, a difference calculation is performed to determine the lower limit threshold of the allowable pressure for reasonably judging whether a minor leak in the pipeline network exceeds the standard.

[0193] Optionally, the current endpoint pressure can be compared with the lower limit threshold of the allowable pressure.

[0194] Meanwhile, the control unit compares the real-time collected endpoint pressure value with the pre-calculated lower limit value in the logic arithmetic unit.

[0195] Optionally, when the current endpoint pressure is lower than the lower limit threshold of the allowable pressure, it is determined that there is gas leakage loss in the system. The system is then connected to an external gas supply channel, which receives external compensation protection gas from an external gas source and injects it into an independent gas storage tank.

[0196] Furthermore, if the comparison result is true, it indicates that the gas mass leaked cumulatively due to flange interface or valve operation during multiple charge-discharge operations has violated the mass conservation principle of the closed-loop cycle. The control unit is connected to external networks such as the plant's low-pressure instrument gas source, allowing external compensation protective gas to be injected into the independent gas storage tank. To calculate the accurate compensation injection amount, the control unit calculates the required external gas mass using a built-in compensation estimation model. The calculation formula for this compensation estimation model is as follows:

[0197] △ makeup =(ρ N2_design -ρ N2_measured )*V N2 ;

[0198] Among them, △ makeup To compensate for the mass of the protective gas, ρ N2_design ρ represents the nitrogen density at the highest pressure and corresponding temperature of the nitrogen storage tank. N2_measured V is the density of nitrogen at the current final pressure and temperature conditions in the nitrogen storage tank. N2 The physical volume of an independent gas storage tank.

[0199] Optionally, the external gas supply channel is shut off when the internal pressure of the independent gas storage tank is detected to return to the design maximum pressure.

[0200] During the operation of the external gas supply channel, the system continuously monitors the pressure recovery trajectory of the independent gas storage tank. When the pressure monitoring curve rises and offsets the leakage drop value throughout the entire life cycle, returning to the design maximum pressure node, the control unit executes a shutdown action to cut off the external gas source connection and restore the independent closed-loop operation state of the asymmetric thermal storage system.

[0201] In another aspect, this embodiment also provides a high-pressure hot water storage tank parallel topology expansion scheme to address the investment problem of high-pressure containers in large-capacity compressed air energy storage power stations, including the following hardware configuration features:

[0202] Optionally, multiple high-pressure hot water storage tanks are provided, and the multiple high-pressure hot water storage tanks are connected in parallel between the cold water delivery pipeline and the hot water delivery pipeline.

[0203] Correspondingly, in large-scale heat transfer scenarios, the manufacturing limitations of individual containers restrict the expansion of total heat storage. This topology solution breaks down a single storage tank into multiple standard high-pressure hot water storage tank modules of suitable volume. Each module is connected to the main circulation network in parallel via a busbar structure on the liquid flow trunk line, sharing the overall physical load of cold water heating and storage and hot water heat release output.

[0204] Optionally, the gas pipeline network has a main pipe section and multiple parallel branch gas lines. One end of each branch gas line is connected to the gas phase space of the corresponding high-pressure hot water storage tank, and the other end is connected to the main pipe section, which is connected to an independent gas storage tank. The upstream end of the first gas line is connected to the gas phase space of multiple high-pressure hot water storage tanks through the main pipe section. Each branch gas line is independently equipped with a gas supply regulating valve.

[0205] Specifically, through this gas network structure, multiple high-pressure hot water storage tanks operating in parallel share a single independent gas storage tank. Under the requirement of independent adjustment under varying operating conditions, when a high-pressure hot water storage tank experiences gas phase instability due to local liquid level fluctuations, the control unit manipulates the gas supply regulating valve on the corresponding branch line to draw and deliver gas from the main pipeline to achieve targeted pressure stabilization.

[0206] Furthermore, to reduce the secondary safety hazards caused by the vapor-liquid two-phase impact easily induced by high-temperature heat flow depressurization, this invention adopts a temperature hard threshold bypass reflux interlock and a cascade flash evaporation separation mechanism to handle flash evaporation potential and ensure the thermodynamic safety of the atmospheric pressure pipeline network. In addition, by combining the operating condition switching sequence of anti-short-circuit interlock with the long-cycle standby micro-leakage compensation strategy, the system avoids mechanical damage caused by gas path direct connection, and improves the long-endurance operation reliability of large-scale energy storage power stations under complex and variable operating conditions.

[0207] In this scenario, the relevant configurations are as follows: Figure 5 As shown, the pressurized hot water partial pressure heat storage system includes: 1 high-pressure hot water storage tank; 1 atmospheric pressure cold water storage tank; 1 independent nitrogen storage tank; 1 cold water booster pump; 1 hot water circulation pump; 1 heat exchanger; 1 air heater; 1 shut-off valve; 1 pressure reducing valve; 1 flash tank; 1 nitrogen booster device (including nitrogen booster pump) and gas supply regulating valve.

[0208] Among them: the high-pressure hot water storage tank has a volume of 4000 m³. 3 The high-pressure hot water storage tank is designed for a pressure of 2.7 MPa; the atmospheric pressure cold water storage tank is designed for atmospheric pressure; the nitrogen storage tank is designed for a pressure of 3.8 MPa; and the nitrogen storage tank has a volume of 900 m³. 3 The nitrogen booster has a head of approximately 1.2 MPa; the hot water storage temperature range is 120~220 ℃.

[0209] During energy storage: The cold water in the atmospheric pressure cold water storage tank is pressurized by the cold water booster pump, absorbs the heat of compression of compressed air in the heat exchanger, and enters the high-pressure hot water storage tank after being heated. As hot water continues to enter, the liquid level in the high-pressure hot water storage tank rises, the top gas phase space decreases, the original high-pressure gas is gradually squeezed out, and recovered into a separate nitrogen storage tank.

[0210] Therefore, the main function of the independent nitrogen storage tank in the energy storage stage is to recover and store the high-pressure gas released from the high-pressure hot water storage tank, so that the internal pressure of the high-pressure hot water storage tank is maintained at about 2.7 MPa.

[0211] During energy release: Hot water in the high-pressure hot water storage tank is pumped into the air heater via a hot water circulation pump to heat the compressed air. As the hot water volume decreases, the gas phase space at the top of the high-pressure hot water storage tank increases.

[0212] At this point, the high-pressure gas recovered during the energy storage phase in the independent nitrogen storage tank is reinjected into the top of the high-pressure hot water storage tank via the gas supply regulating valve to fill the newly added gas phase space, maintaining the pressure of the high-pressure hot water storage tank at 2.7 MPa. The released low-temperature water enters the atmospheric pressure cold water storage tank after passing through the pressure reducing valve.

[0213] In another embodiment, multiple high-pressure hot water storage tanks can be installed in parallel, sharing an independent gas storage tank.

[0214] Each high-pressure hot water storage tank is connected to the same nitrogen storage tank via a branch line, and each branch line is equipped with an independent gas supply regulating valve. When a change in the liquid level of a hot water storage tank causes pressure fluctuations, its corresponding gas supply regulating valve automatically adjusts to stabilize the pressure of multiple hot water storage tanks.

[0215] This implementation method is applicable to large-capacity compressed air energy storage systems and can reduce the number of nitrogen storage tanks and system cost.

[0216] In addition to nitrogen, gases such as air, carbon dioxide, and argon can also be used in independent gas storage tanks; these gases do not react significantly with hot water.

[0217] In one exemplary embodiment, this application also provides a computer program product, which includes a computer program that, when executed by a processor, implements the steps in any of the above method embodiments.

[0218] Embodiments of this application also provide a computer program that includes computer instructions stored in a computer-readable storage medium; a processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the steps in any of the above method embodiments.

[0219] Specific examples in this embodiment can be found in the examples described in the above embodiments and exemplary implementations, and will not be repeated here.

[0220] Obviously, those skilled in the art should understand that the modules or steps of this application described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented here, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, this application is not limited to any particular combination of hardware and software.

Claims

1. A pressurized hot water partial pressure thermal storage system for compressed air energy storage, comprising a high-pressure hot water storage tank, an atmospheric pressure cold water storage tank, an independent gas storage tank, a cold water delivery pipeline, a hot water delivery pipeline, and a gas pipeline network, characterized in that, include: The cold water delivery pipeline connects the internal cavities of the atmospheric pressure cold water storage tank and the high pressure hot water storage tank. A cold water booster pump and a main heat exchanger are connected in series along the fluid flow direction on the cold water delivery pipeline, and the outlet end of the cold water delivery pipeline extends to the liquid phase region of the internal cavity of the high pressure hot water storage tank. The hot water delivery pipeline connects the internal cavity of the high-pressure hot water storage tank to the atmospheric pressure cold water storage tank. The upstream end of the hot water delivery pipeline is connected to the liquid phase region of the internal cavity of the high-pressure hot water storage tank. A hot water circulation pump, an air heater, and a pressure reducing component are connected in series along the fluid flow direction on the hot water delivery pipeline. The gas pipeline network connects the gas phase space of the high-pressure hot water storage tank and the high-pressure gas storage chamber of the independent gas storage tank. The gas pipeline network includes a first gas line and a second gas line that are independent of each other. The upstream end of the first gas line is connected to the gas phase space of the high-pressure hot water storage tank, and the downstream end is connected to the independent gas storage tank. A gas pressure boosting device is connected in series on the first gas line. The upstream end of the second gas line is connected to the independent gas storage tank, and the downstream end is connected to the gas phase space of the high-pressure hot water storage tank. A gas supply regulating valve is installed on the second gas line. The physical volume of the independent gas storage tank is configured as a static parameter boundary. The physical volume is equal to the product of the effective liquid phase volume change in the liquid phase region of the high-pressure hot water storage tank during a single energy storage and release cycle and the rated operating pressure of the high-pressure hot water storage tank, divided by the pressure difference between the design maximum pressure of the independent gas storage tank and the rated operating pressure of the high-pressure hot water storage tank. The gas phase space inside the high-pressure hot water storage tank retains a minimum safe gas phase volume to prevent liquid from entering the gas pipeline network at the highest operating liquid level.

2. The pressurized hot water partial pressure heat storage system according to claim 1, characterized in that, include: The pressure reducing assembly includes a single-stage pressure reducing valve and a bypass reflux unit; A single-stage pressure reducing valve is connected in series on the hot water delivery pipeline and is located between the air heater and the atmospheric pressure cold water storage tank; The bypass return unit includes a bypass pipeline and a bypass valve installed on the bypass pipeline. The upstream end of the bypass pipeline is connected to the hot water delivery pipeline between the air heater and the single-stage pressure reducing valve, and the downstream end is connected to the internal cavity of the high-pressure hot water storage tank.

3. The pressurized hot water partial pressure heat storage system according to claim 1, characterized in that, include: The pressure reducing assembly includes a first-stage pressure reducing valve, an intermediate flash tank, and a second-stage pressure reducing valve connected in series along the fluid flow direction. The intermediate flash tank has an internal cavity for vapor-liquid separation, and the liquid phase outlet at the bottom of the intermediate flash tank is connected to the inlet of the second-stage pressure reducing valve. The pressure reducing assembly also includes a preheating heat exchanger. The vapor phase outlet at the top of the intermediate flash tank is connected to the hot side inlet of the preheating heat exchanger via a steam pipeline. The hot side outlet of the preheating heat exchanger is connected to the atmospheric pressure cold water storage tank. The cold side of the preheating heat exchanger is connected in series to the cold water delivery pipeline between the atmospheric pressure cold water storage tank and the main heat exchanger.

4. An operation method for a pressurized hot water partial pressure thermal storage system based on any one of claims 1 to 3, characterized in that, include: During the energy storage phase, it receives atmospheric pressure cold water from an atmospheric pressure cold water storage tank; High-pressure hot water is obtained by pressurizing atmospheric cold water and using heat exchange through the absorption of compression heat; the high-pressure hot water is then injected into the liquid phase region of a high-pressure hot water storage tank for storage. The system simultaneously receives the initial protective gas squeezed out of the high-pressure hot water storage tank due to the rise in the liquid level in the liquid phase zone; it uses a gas pressurization device to pressurize the initial protective gas to obtain pressurized protective gas; and it discharges the pressurized protective gas into an independent gas storage tank for storage. During the energy release phase, high-pressure hot water is received from the high-pressure hot water storage tank; the high-pressure hot water is used to heat the air to be expanded to obtain heat release return water; the pressure reduction component is used to depressurize the heat release return water to obtain atmospheric pressure low-temperature water; the atmospheric pressure low-temperature water is sent back to the atmospheric pressure cold water storage tank. It synchronously receives pressurized protective gas from an independent gas storage tank; based on the volume change caused by the drop in liquid level in the liquid phase zone inside the high-pressure hot water storage tank, it injects pressurized protective gas into the gas phase space of the high-pressure hot water storage tank through a gas supply regulating valve to maintain the internal operating pressure of the high-pressure hot water storage tank at the rated operating pressure.

5. The operating method according to claim 4, characterized in that, Before the step of depressurizing the returned water after heat release using a pressure reducing device, a flash evaporation prevention safety control step is also included: Real-time acquisition of the current return water temperature after heat release; Obtain the pre-configured temperature safety threshold and compare the current return water temperature with the temperature safety threshold; When the current return water temperature is higher than the temperature safety threshold, the interlock protection mechanism is triggered. Specifically, the operation of depressurizing the return water after heat release using the pressure reducing component is stopped, and the preset bypass return path is opened to guide the return water after heat release back to the liquid phase zone of the high-pressure hot water storage tank for circulation. The operation of depressurizing the returned water after heat release will resume once the current return water temperature is detected to drop below the safe temperature threshold.

6. The operating method according to claim 4, characterized in that, When switching from the energy storage stage to the energy release stage, the following timing sequence is followed for the seamless switching control of the operating condition: Gradually reduce the operating frequency of the chilled water booster pump until it stops, and simultaneously control the gas booster device to slow down until it stops. Close the first gas line; Open the gas supply regulating valve to the preset initial opening value and monitor and confirm that the internal operating pressure of the high-pressure hot water storage tank has reached the initial pressure stabilization state; Start the hot water circulation pump and activate the pressure reducing component to establish a complete energy release fluid channel; During the entire operating condition switching and system operation cycle, the first air circuit and the air supply regulating valve are simultaneously in the open state.

7. The operating method according to claim 4, characterized in that, After the energy storage phase ends, a step to compensate for the loss of protective gas is also included: Obtain the current endpoint pressure within an independent gas storage tank; Obtain the design maximum pressure of the pre-configured independent gas storage tank, and calculate the lower limit threshold of the allowable pressure based on the preset pressure loss ratio; Compare the current endpoint pressure with the lower limit threshold of the allowable pressure; When the current endpoint pressure is lower than the lower limit threshold of the allowable pressure, it is determined that there is gas leakage loss in the system. The external gas supply channel connected to the system is connected to obtain external compensation protection gas provided by the external gas source and inject it into the independent gas storage tank. When the internal pressure of the independent gas storage tank is detected to return to the design maximum pressure, the external gas supply channel is shut off.

8. The operating method according to claim 4, characterized in that, Prior to the initial energy storage phase, there is also an initial pressurization and build-up process for cold startup of the system: Connect to an external initial gas source and continuously inject gas into the high-pressure hot water storage tank and the independent gas storage tank until the pressure in the high-pressure hot water storage tank reaches the rated operating pressure. Start the cold water booster pump to inject high-pressure hot water that has undergone heat exchange, and at the same time, use the gas booster device to continuously transfer the gas squeezed out by the rising liquid level to the independent gas storage tank. When the liquid phase zone inside the high-pressure hot water storage tank reaches the designed maximum liquid level, the system is initially pressurized and the control system enters normal operation standby state.

9. The operating method according to claim 4, characterized in that, During prolonged periods of quiescent operation between the energy storage and energy release phases, a quiescent pressure maintenance procedure is performed: Continuously monitor the internal operating pressure of the high-pressure hot water storage tank; When the internal operating pressure falls below the preset static maintenance lower limit due to heat loss during static operation, the gas supply regulating valve is opened to perform a small pressure replenishment operation. When the internal operating pressure returns to the target set value, close the gas supply regulating valve to maintain stable system pressure during the resting period.

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