Switchable heat pipe compressed air energy storage heat exchange system and control method

Abstract

The application belongs to the technical field of compressed air energy storage heat exchange, and provides a switchable heat pipe compressed air energy storage heat exchange system and a control method. The system comprises an air switching device, a gas cavity, a gas end heat pipe device, a phase change liquid storage tank, a heat pipe mode switching pump, an energy storage end heat pipe device, a phase change liquid distribution cavity, a controller and an energy storage tank. The phase change liquid distribution cavity is connected to the input end of the energy storage end heat pipe device. The controller controls the on-off state of the air switching device, the operating state of the heat pipe mode switching pump, and the opening and closing state of the phase change liquid pipeline valve and the phase change liquid storage tank valve, so as to switch the evaporation section and the condensation section of the gas end heat pipe device and the energy storage end heat pipe device. The application realizes efficient and rapid heat exchange between compressed air and heat storage medium, significantly reduces the required heat exchange area and system volume, and improves the heat exchange efficiency.

Description

Technical Field

[0001] This invention relates to the field of compressed air energy storage and heat exchange technology, and in particular to a switchable heat pipe compressed air energy storage and heat exchange system and control method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] With the continuous expansion of renewable energy generation, the stable operation of the power grid faces severe challenges. Compressed air energy storage (CAES) technology, as a large-scale, long-term physical energy storage method, plays an important role in achieving peak shaving and valley filling of the power grid, promoting the consumption of new energy sources, and reducing carbon emissions. Traditional compressed air energy storage still faces bottlenecks in energy conversion efficiency. During the energy storage process, the compression of air generates a large amount of heat energy, which will be wasted if not recovered; during the energy release process, the compressed air needs to be reheated before entering the turbine to expand and do work in order to improve its work capacity. Therefore, advanced compressed air energy storage systems usually integrate thermal storage components.

[0004] In existing technologies, independent heat storage medium (such as heat transfer oil, molten salt, etc.) and circulation loops are commonly used. The heat exchanger absorbs heat from the air during compression and releases heat to the air during expansion. However, this existing solution has the following problems: (1) The circulation and transportation of the heat storage medium depends on a high-power working medium pump, which itself requires significant compression work, reducing the net efficiency of the system; Traditional indirect heat exchangers have the problems of large heat transfer temperature difference and relatively low heat exchange efficiency. In order to achieve the required heat exchange capacity, it is often necessary to increase the heat exchange area, which leads to the heat exchange system and connecting pipes (1) The road is large in volume, complex in structure and expensive; (2) The large thermal inertial system has a slow response speed and is difficult to quickly match the needs of compressor and turbine to change operating conditions. This not only reduces the adjustment flexibility of the entire power station, but may also cause fluid mechanical surge problems in the multi-stage compression process, threatening the safe and stable operation of the system; (3) As a highly efficient passive heat transfer element, the heat transfer efficiency of the heat pipe is much higher than that of conventional metal heat conduction. However, the traditional heat pipe has a fixed function and cannot adapt to the need for the reverse heat flow direction in the two stages of "heat storage" and "heat release" in compressed air energy storage. Summary of the Invention

[0005] To address the problems of high power consumption of the working fluid pump, low efficiency of traditional heat exchangers, slow system response, and potential surge in existing compressed air energy storage systems, this invention provides a switchable heat pipe compressed air energy storage heat exchange system and control method. It employs a functionally reversible heat pipe heat exchanger system, with a specific working fluid inside. Through a switching and control mechanism, the evaporation and condensation sections of the heat pipe can be dynamically changed depending on whether the system is in energy storage or energy release mode. During the energy storage phase, the high-temperature compressed air from the compressor unit flows through what is designated as the "evaporation section." The heat exchange channel heats the heat pipe working fluid, causing it to evaporate. The vapor flows to the other end (condensation section) and condenses, transferring heat to the heat storage material to achieve heat storage. This process utilizes the efficient heat transfer characteristics of the heat pipe to quickly remove the heat of compression. In the energy release stage, by controlling the corresponding valves to switch the flow channels, the working fluid from the heat storage material flows through the original "condensation section" (now switched to the "evaporation section") to heat the heat pipe working fluid, while its vapor flows to the other end (now switched to the "condensation section") and condenses, releasing heat to preheat the low-temperature, high-pressure air that is about to enter the turbine expander.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a switchable heat pipe compressed air energy storage and heat exchange system.

[0008] A switchable heat pipe compressed air energy storage and heat exchange system includes an air switching device, a gas cavity, a gas end heat pipe device, a phase change liquid storage tank, a heat pipe mode switching pump, an energy storage end heat pipe device, a phase change liquid distribution chamber, a controller, and an energy storage tank. The phase change liquid distribution chamber is connected to the input end of the energy storage end heat pipe device.

[0009] The air switching device is connected to the compressor, turbine and gas chamber respectively through gas pipelines. The gas end heat pipe device is installed in the gas chamber. The phase change liquid storage tank is connected to the energy storage end heat pipe device through the phase change liquid pipeline. The phase change liquid pipeline is equipped with a heat pipe mode switching pump and a phase change liquid pipeline valve. The phase change liquid storage tank is connected to the gas end heat pipe device through the phase change liquid storage tank valve.

[0010] The heat pipe device at the energy storage end is immersed in the heat storage medium in the energy storage tank. The controller is electrically connected to the air switching device, the heat pipe mode switching pump, the phase change liquid pipeline valve, and the phase change liquid storage tank valve. The controller switches the functions of the evaporation section and the condensation section of the gas-end heat pipe device and the energy storage end heat pipe device by controlling the on / off state of the air switching device, the operating state of the heat pipe mode switching pump, and the opening / closing state of the phase change liquid pipeline valve and the phase change liquid storage tank valve.

[0011] In one implementation of the first aspect of the present invention, both the gas-end heat pipe device and the energy storage-end heat pipe device are array-type modular structures, and the number of arrays and modules are adapted according to the heat exchange power.

[0012] In one implementation of the first aspect of the present invention, each independent heat pipe of the energy storage end heat pipe device is provided with an upwardly inclined spiral groove, so that the phase change liquid can flow along the upwardly inclined spiral groove and exchange heat with the heat storage medium.

[0013] In one implementation of the first aspect of the present invention, a phase change liquid pipeline valve is connected in series in the pipeline between the gas-end heat pipe device and the energy storage heat pipe device, for opening and closing the phase change liquid flow channel between the gas-end heat pipe device and the energy storage heat pipe device; a phase change liquid storage tank valve is connected in series in the pipeline between the gas-end heat pipe device and the heat pipe mode switching pump, for opening and closing the phase change liquid flow channel between the gas-end heat pipe device and the heat pipe mode switching pump.

[0014] In one implementation of the first aspect of the present invention, the air switching device is provided with two sets of control valves. One set of control valves is used to switch the gas pipeline between the compressor and the air chamber, and the other set of control valves is used to switch the gas pipeline between the turbine and the air chamber. The two sets of control valves are not in the open state at the same time.

[0015] Secondly, the present invention provides a switchable heat pipe compressed air energy storage and heat exchange control method.

[0016] A switchable heat pipe compressed air energy storage heat exchange control method, utilizing the switchable heat pipe compressed air energy storage heat exchange system of the first aspect of the present invention, includes the following processes:

[0017] The controller controls the air switching device to open the pipeline between the compressor and the air chamber, close the pipeline between the turbine and the air chamber, open the phase change liquid pipeline valve, and close the phase change liquid storage tank valve.

[0018] Start the compressor to deliver the high-temperature, high-pressure air formed by compression to the air chamber;

[0019] The gas end heat pipe device inside the gas cavity absorbs heat from the high-temperature and high-pressure air, causing the internally stored phase change liquid to evaporate into a gas phase.

[0020] The gaseous phase change liquid flows along the pipeline to the heat pipe device at the energy storage end, where it exchanges heat with the heat storage medium in the energy storage tank and then condenses into a liquid phase.

[0021] The liquid phase change liquid flows back to the gas end heat pipe device along the pipeline where the phase change liquid pipeline valve is located, completing one heat exchange cycle.

[0022] In one implementation of the second aspect of the present invention, the controller controls the air switching device to close the pipeline between the compressor and the air chamber, open the pipeline between the turbine and the air chamber, close the phase change liquid pipeline valve, and open the phase change liquid storage tank valve.

[0023] The low-temperature, high-pressure air from the external gas storage device is delivered to the gas chamber, and the controller simultaneously activates the heat pipe mode switching pump.

[0024] The heat pipe mode switching pump pumps the phase change liquid in the phase change liquid storage tank to the phase change liquid distribution chamber, and after being evenly distributed by the phase change liquid distribution chamber, it flows into the heat pipe device at the energy storage end.

[0025] The phase change fluid absorbs heat from the heat storage medium in the energy storage tank within the heat pipe device at the energy storage end and evaporates into a gas phase;

[0026] The gas phase change liquid flows along the pipeline to the gas end heat pipe device, where it condenses into a liquid phase and releases heat. This heat is used to heat the low-temperature, high-pressure air inside the gas chamber.

[0027] The liquid phase change fluid flows back to the phase change fluid storage tank along the pipeline where the valve of the phase change fluid storage tank is located, completing one heat exchange cycle;

[0028] The heated high-pressure air is transported along the pipeline to the turbine, which drives the turbine to run.

[0029] In one implementation of the second aspect of the present invention, a flow sensor is provided at the lower end of the outlet of the inclined spiral groove of the energy storage heat pipe device, and the flow sensor is electrically connected to the controller.

[0030] During the heat exchange process for energy release and power generation, the flow sensor detects the flow rate of the liquid phase change liquid at the outlet of the inclined spiral channel in real time and transmits the detected flow signal to the controller.

[0031] After receiving the flow signal, the controller makes a judgment and adjusts the speed of the heat pipe mode switching pump: if the detected flow is greater than the set upper limit threshold, the controller controls the heat pipe mode switching pump to reduce the speed; if the detected flow is zero, the controller controls the heat pipe mode switching pump to increase the speed; if the detected flow fluctuates intermittently near the zero threshold, the controller controls the heat pipe mode switching pump to maintain the current speed.

[0032] In one implementation of the second aspect of the present invention, the controller can monitor in real time the air temperature of the air chamber, the air pressure of the air chamber, the temperature of the heat storage medium in the energy storage tank and the air flow of the turbine, and adjust the speed of the heat pipe mode switching pump according to the monitored parameters.

[0033] In one implementation of the second aspect of the present invention, during the compression and energy storage stage, the circulation channel of the phase change fluid is composed of a gas-end heat pipe device, a phase change fluid pipeline valve, and an energy storage-end heat pipe device; during the energy release and power generation stage, the circulation channel of the phase change fluid is composed of a phase change fluid storage tank, a heat pipe mode switching pump, a phase change fluid distribution chamber, an energy storage-end heat pipe device, a gas-end heat pipe device, and a phase change fluid storage tank valve.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] This invention utilizes the extremely high equivalent thermal conductivity of heat pipes to achieve efficient and rapid heat exchange between compressed air and the heat storage medium, significantly reducing the required heat exchange area and system volume. Through the flow channel switching design, a single heat exchange device replaces the traditional two independent heat exchangers (interstage cooler and prestage heater) and the complex heat storage medium circulation loop, eliminating the need for the pump driving the heat storage medium circulation, fundamentally eliminating the power consumption of this part, and improving system efficiency.

[0036] The rapid response characteristics of the heat pipe in this invention enable the heat exchange system to quickly keep up with the power changes of the compressor and turbine, improving the load tracking capability and operational flexibility of the entire power plant and effectively mitigating the surge risk caused by slow response. The compressed air energy storage heat exchange control method of this invention, based on system operating mode signals, automatically controls valve switching and flow regulation, ensuring efficient and stable operation of the heat pipe in both operating phases, thereby achieving a comprehensive improvement in the efficiency and reliability of the compressed air energy storage power plant.

[0037] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0038] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0039] Figure 1 A schematic diagram of a switchable heat pipe compressed air energy storage and heat exchange system for an exemplary embodiment of the present invention is provided.

[0040] Figure 2 A schematic diagram of a switchable heat pipe compressed air energy storage and heat exchange system for energy release and power generation, provided as an exemplary embodiment of the present invention;

[0041] Figure 3 A phase change liquid control strategy for the energy release and power generation stage provided as an exemplary embodiment of the present invention;

[0042] Figure 4An illustration showing the effect of applying the present invention to a 300MW compressed air energy storage power station, as an exemplary embodiment of the present invention;

[0043] The components include: 1. Air switching device; 2. First gas pipeline; 3. Gas chamber; 4. Controller; 5. Gas end heat pipe device; 6. Energy storage tank; 7. Energy storage end heat pipe device; 8. Upper inclined spiral groove; 9. Phase change liquid distribution chamber; 10. Phase change liquid pipeline; 11. Phase change liquid pipeline valve; 12. Flow sensor; 13. Phase change liquid; 14. Phase change liquid storage tank valve; 15. Heat pipe mode switching pump; 16. Phase change liquid storage tank; and 17. Second gas pipeline. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0045] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0046] This implementation proposes a switchable heat pipe compressed air energy storage and heat exchange system, such as... Figure 1 and Figure 2 As shown, the system includes an air switching device 1, a gas chamber 3, a gas end heat pipe device 5, a phase change liquid storage tank 16, a heat pipe mode switching pump 15, an energy storage end heat pipe device 7, a phase change liquid distribution chamber 9, a controller 4, an energy storage tank 6, a phase change liquid pipeline valve 11, and a phase change liquid storage tank valve 14.

[0047] Air switching device 1 is connected to air chamber 3 through first gas pipeline 2. Air switching device 1 is connected to compressor and turbine through other gas pipelines respectively. Controller 4 controls the opening and closing of valves in air switching device 1. During the compressed energy storage stage, the compressor and air chamber are connected and the valve of the pipeline leading to turbine is closed. During the energy release and power generation stage, the turbine and air chamber are connected and the valve of the pipeline leading to compressor is closed.

[0048] In this implementation, the gas chamber 3 is connected to the second gas pipeline 17, which is used to connect to the next stage compressor or salt cavern.

[0049] The gas chamber 3 is the outer shell of the heat pipe heat exchanger. Its function is to store compressed high-pressure hot air or high-pressure cold air waiting to be heated and enter the turbine. The gas end heat pipe device 5 is installed in the gas chamber.

[0050] In this implementation, the gas-end heat pipe device 5 has a dual function: firstly, it absorbs the heat of the compressed air during the compression and energy storage stage, thereby reducing the temperature of the compressed air, evaporating the phase change liquid 13 into a gas, and transferring heat to the condensation section; secondly, during the energy release and power generation stage, it condenses the phase change vapor into a liquid, releases heat to the high-pressure cold air, and increases the energy of the compressed air supplied to the turbine.

[0051] In this implementation, the phase change liquid storage tank 16 is used to store the phase change liquid 13. The phase change liquid 13 is controlled by a valve to be either located in the heat pipe end of the gas chamber or can flow to the phase change liquid storage tank 16 of the energy storage end heat pipe device 7, thereby realizing the switching of the heat pipe evaporation section / condensation section function.

[0052] In this implementation, the function of the heat pipe mode switching pump 15 is to pump the phase change liquid 13 to the energy storage end heat pipe device 7 to realize the switching of the energy storage end heat pipe device from heat release function to heat absorption function.

[0053] In this implementation, the energy storage end heat pipe device 7 also has a dual function: firstly, it cools the vapor of the phase change liquid 13 during the compression energy storage stage, transferring heat to the energy storage medium in the energy storage tank 6; secondly, during the energy release and power generation stage, it absorbs the heat of the energy storage medium in the energy storage tank 6, converts the phase change liquid 13 into a gas phase, and flows to the gas end heat pipe device 5. The gas end heat pipe device 5 releases heat and converts into liquid, transferring the heat to the air to raise its temperature and increase its energy.

[0054] In this implementation, the function of the phase change fluid distribution chamber 9 is to evenly distribute the phase change fluid 13 flowing from the heat pipe mode switching pump 15 into each heat pipe.

[0055] In this implementation, the function of the energy storage tank 6 is to utilize the heat released by the compressed air during the high-pressure compressed air or phase change material energy storage stage, and transfer it to the cold high-pressure compressed air during the energy release stage.

[0056] In this implementation, the controller 4 is used to enable flexible switching between energy storage and energy release in the switchable heat pipe air energy storage system, and to control the flow rate of the phase change liquid 13 according to the air flow rate, so as to achieve efficient heat exchange and save pump liquid energy consumption.

[0057] In this implementation, in order to increase the area and improve the heat exchange efficiency, the gas end heat pipe device 5 and the energy storage end heat pipe device 7 are array structures, designed as modules. The number of arrays and modules are selected according to the heat exchange power of the compressed air energy storage power station.

[0058] In this implementation, each independent heat pipe of the energy storage end heat pipe device 7 has a novel structural form, characterized by an inclined spiral groove 8 arranged inside the heat pipe. This inclined spiral groove 8 allows the phase change liquid 13 to be stored in the spiral groove and flow spirally from top to bottom. During the flow process, it absorbs the heat transferred from the outside of the heat pipe, causing the phase change liquid 13 to evaporate. The flow rate of the phase change liquid 13 can be controlled by the heat pipe mode switching pump 15. This novel heat pipe structure breaks through the gravity limitation of traditional heat pipes and can realize the transfer of heat from the hot end located at a high position to the cold end located at a low position.

[0059] In this implementation, during the compression energy storage stage, the phase change liquid 13 has a high temperature gas end heat pipe device 5. The phase change liquid 13 absorbs the heat of the compressed hot air and evaporates into a gas phase. The gas phase flows to the condensation section, releases heat and becomes liquid. Under the action of gravity, it flows back to the gas end heat pipe device 5, achieving efficient energy storage without relying on power.

[0060] In this implementation, during the energy release phase, the phase change liquid 13 flows into the phase change liquid storage tank 16 through the phase change liquid storage tank valve 14, with the liquid level below the gas end heat pipe device 5. The phase change liquid 13 is pumped to the upper part of the energy storage end heat pipe device 7 using the heat pipe mode switching pump 15, and evenly distributed to each new upward inclined spiral groove 8 heat pipe through the phase change liquid distribution chamber 9. It absorbs heat and evaporates into gas. The gas releases heat with the gas end heat pipe device 5 located in the condensation section and transforms into liquid, flowing back to the phase change liquid storage tank 16. At the same time, the pressure of the gas end heat pipe device 5 in the condensation section decreases. Under the action of pressure difference, the gas phase evaporated from the energy storage end heat pipe device 7 does not flow short-circuit to the condensation section. Only by relying on the heat pipe mode switching pump 15 with a small power consumption, the heat transfer from the energy storage tank 6 to the high-pressure cold air is realized during the energy release phase.

[0061] Based on the aforementioned switchable heat pipe compressed air energy storage and heat exchange system, this implementation proposes a switchable heat pipe compressed air energy storage and heat exchange control method, including a compression energy storage stage and an energy release and power generation stage.

[0062] The compression energy storage stage specifically includes the following processes:

[0063] S101: Controller 4 has issued a command to close the valve on the gas line leading to the turbine and open the valve on the first gas line 2 leading to the compressor. At this time, a smooth flow path is formed between the compressor and the gas chamber 3.

[0064] S102: After the phase change fluid circuit is determined, the phase change fluid storage tank valve 14 is in the closed state, cutting off the connection between the phase change fluid storage tank 16 and the main circuit. Figure 1 As shown; at the same time, the phase change liquid pipeline valve 11 is closed, which allows the liquid phase change liquid 13 to naturally collect and fill the pipeline of the gas end heat pipe device 5 located at the bottom of the system under the action of gravity.

[0065] S103: After confirming that all valves are in the correct position, controller 4 sends a "ready" signal to the power plant's main control system. Subsequently, the start command is issued, and the high-power multi-stage compressor begins to operate, drawing in ambient air and compressing it stage by stage. During the compression process, the air temperature rises sharply, and this high-temperature, high-pressure air continuously flows into the air chamber 3 through the opened first gas pipeline 2.

[0066] S104: The gas chamber 3 serves as a high-pressure gas buffer and heat exchange space, with an array of gas-end heat pipe devices 5 densely arranged inside. When high-temperature air flows through the outer wall of these heat pipes, heat is rapidly transferred through the pipe wall to the liquid phase change liquid 13 inside the pipe. Since the gas-end heat pipe device 5 is filled with phase change liquid, the phase change liquid absorbs a large amount of latent heat of vaporization and instantly evaporates into saturated vapor. This process efficiently removes the heat from the compressed air, causing its temperature to drop significantly, for example, to about 50°C, when it leaves the gas chamber, thus completing the cooling of the compressed air. The cooled high-pressure air is then transported to an underground gas storage facility or a high-pressure storage tank for storage.

[0067] S105: The generated phase change working fluid vapor, driven by its own pressure vapor differential, flows at high speed along the pipe of the gas end heat pipe device 5 to the energy storage end heat pipe device 7 located above the system. This process achieves rapid long-distance heat transfer with almost zero loss.

[0068] S106: The heat pipe device 7 at the energy storage end is immersed in the heat storage medium of the energy storage tank 6. In this stage, this section operates as the "condensation section," where high-temperature steam flowing from the evaporation section exchanges heat with the lower-temperature heat storage medium. The steam releases its latent heat of condensation and re-condenses into a liquid state. This portion of the condensation heat is efficiently transferred to the phase change heat storage material inside the energy storage tank 6. After absorbing heat, the heat storage material's temperature rises and undergoes a phase change, melting from a solid to a liquid state, storing the heat of compression in the form of latent heat on a large scale and at high density.

[0069] S107: The liquid phase change liquid condensed in the condensation section of the energy storage end heat pipe device 7 flows back to the evaporation section of the gas end heat pipe device 5 located at the bottom of the system under the action of gravity through the opened phase change liquid pipeline 10, and rejoins a new round of evaporation-condensation cycle.

[0070] S108: Throughout the compression and energy storage phase, controller 4 continuously monitors key operating parameters, including the inlet air temperature and pressure of gas chamber 3, the core temperature of energy storage tank 6, and the temperature field distribution at various points in the system. Through a built-in algorithm model, the controller ensures that the entire heat pipe heat exchange system always operates under optimal conditions. Since heat pipe heat transfer mainly relies on latent heat of phase change and small pressure differences, its heat transfer efficiency is extremely high, and its response is rapid. It can quickly keep up with changes in compressor load, effectively avoiding surge problems that may be caused by untimely heat exchange.

[0071] The energy release and power generation stage specifically includes the following processes:

[0072] S201: Air path switching. Controller 4 sends a command to air switching device 1 to close the valve of the first gas pipeline 2 leading to the compressor, and at the same time open the valve of the gas pipeline leading to the turbine. The flow path of high-pressure air is switched from "compression path" to "power generation path".

[0073] S202: Phase change fluid loop reconfiguration. Controller 4 first closes the phase change fluid pipeline valve 11, cutting off the direct gravity return path between the gas-end heat pipe device 5 and the energy storage-end heat pipe device 7. Then, it opens the phase change fluid storage tank valve 14. At this time, all the liquid phase change fluid 13 in the system collects into the phase change fluid storage tank 16 under gravity, causing the liquid level inside the gas-end heat pipe device 5 to drop to the lower part of its pipeline.

[0074] S203: Heat pipe mode switching pump 15 on standby: Heat pipe mode switching pump 15 is activated by the controller and enters the standby state.

[0075] S204: Start the turbine and cold air supply. High-pressure air at room temperature of about 25°C is released from the gas storage tank and flows into the gas chamber 3 through the gas pipeline. At this time, the throttle valve in front of the turbine inlet slowly opens, and this high-pressure cold air begins to flow through the gas chamber 3, ready to enter the turbine to expand and do work.

[0076] S205: Start the heat pipe mode switching pump and phase change fluid distribution. At the same time as the turbine starts, the controller 4 starts the heat pipe mode switching pump 15. The pump draws the liquid phase change fluid 13 from the phase change fluid storage tank 16 and pumps it through the pipeline to the phase change fluid distribution chamber 9 at the top of the system. The design of the distribution chamber ensures that the phase change fluid is evenly distributed to each independent heat pipe of the energy storage end heat pipe device 7.

[0077] S206: The heat absorption and evaporation functions of the heat pipe device at the energy storage end are reversed to form an "evaporation section." At this stage, the function of the heat pipe device 7 at the energy storage end undergoes a fundamental reversal, transforming from a "condensation section" in the energy storage stage to an "evaporation section." The pumped liquid phase change fluid flows into its innovative upward-sloping spiral groove structure 8. These spiral grooves capture the liquid, causing it to form a slowly and uniformly spreading liquid film along the channels. During the downward flow, the liquid film fully contacts the pipe wall and continuously and efficiently absorbs the latent heat of phase change released by the heat storage medium from the energy storage tank 6. After absorbing heat, the phase change fluid evaporates into a gas phase within the spiral grooves.

[0078] S207: The phase change working fluid vapor generated in the evaporation section of the energy storage end heat pipe device 7 automatically flows to the gas end heat pipe device 5, which is now the "condensation section", driven by the pressure in the pressure difference evaporation section being higher than that in the condensation section.

[0079] S208: Due to the drop in liquid level, most of the interior of the gas-end heat pipe device 5 is no longer liquid, transforming into a "condensation section." High-temperature steam flowing from the evaporation section exchanges heat here with low-temperature, high-pressure air flowing through the gas chamber 3. Upon encountering the cooler pipe wall, the steam releases its latent heat of condensation and condenses into a liquid state. This released heat is rapidly transferred through the pipe wall to the high-pressure cold air, causing its temperature to rise rapidly. The preheated, greatly increased-energy high-pressure air then enters the turbine expander, driving the turbine rotor to rotate at high speed, which in turn drives the generator to output electrical energy.

[0080] S209: The liquid phase change fluid condensed in the gas-end heat pipe device 5 drips down under gravity and flows back to the phase change fluid storage tank 16 through the open phase change fluid storage tank valve 14, completing one cycle. Subsequently, the heat pipe mode switching pump 15 pumps these liquids to the top again to start a new round of heat absorption-heat transfer-heat release process.

[0081] S210: Throughout the energy release and power generation phase, controller 4 monitors the turbine's inlet air flow and temperature in real time, dynamically adjusting the speed of heat pipe mode switching pump 15 to precisely control the circulation flow of the phase change fluid. When the power generation load increases and the air flow is high, the pump speed is increased to enhance heat transfer power; when the load decreases, the pump speed is reduced to save pump fluid energy consumption. This adaptive control ensures that the system operates with the highest heat exchange efficiency and lowest operating cost under any conditions.

[0082] In this implementation, preferably, to achieve optimal operation of the evaporation section of the upwardly inclined spiral groove 8 within the energy storage heat pipe device 7, a phase change liquid control strategy is proposed during the energy release and power generation stage: by monitoring the liquid phase outflow status at the lower end of the upwardly inclined spiral groove 8, the flow rate of the heat pipe mode switching pump 15 is determined and adjusted in real time, so that the supply of phase change liquid 13 is dynamically matched with the evaporation rate, thereby achieving the optimal operating condition of "complete evaporation of the liquid film and zero liquid redundancy". Specifically, it includes the following processes:

[0083] (1) Target state definition.

[0084] Optimal state (moderate flow rate): The phase change liquid 13 pumped by the heat pipe mode switching pump 15 evaporates completely after flowing through the entire length of the upper inclined spiral groove 8. At this time, no liquid phase change liquid flows down the lower end of the upper inclined spiral groove 8, or only a very small amount of unevaporated residual liquid. This indicates that all the supplied heat has been used for the phase change of the working fluid, the heat transfer area is fully utilized, and the pumping power consumption is the lowest.

[0085] Non-optimal state 1 (excessive flow rate): A large amount of unevaporated liquid phase change liquid 13 continues to flow down the lower end of the channel of the upwardly inclined spiral channel 8. This indicates that the pumping flow rate of the heat pipe mode switching pump 15 exceeds the evaporation capacity under the current heat load, resulting in a waste of phase change liquid 13. The excess phase change liquid 13 not only does not participate in effective heat exchange, but also requires additional pumping power to lift it to a higher position, and may cause unnecessary flash evaporation or pressure fluctuations in the downstream phase change liquid storage tank 16, leading to a decrease in system efficiency.

[0086] Non-optimal state two (insufficient flow): The lower end of the channel of the upward-sloping spiral channel 8 is dry, with no liquid flowing down. This indicates that the pumping flow of the heat pipe mode switching pump 15 is insufficient and cannot maintain a complete liquid film covering the entire upward-sloping spiral channel 8. This will cause part of the channel surface of the upward-sloping spiral channel 8 to "dry up", reducing the evaporation heat exchange area and increasing the heat transfer resistance. This will reduce the rate of heat extraction from the energy storage tank 6, ultimately resulting in the preheating temperature of the turbine inlet air not meeting the standard, affecting the power generation.

[0087] (2) Specific control logic.

[0088] First, a high-sensitivity flow sensor 12 is installed at the lower end of the outlet of each or more representative heat pipes of the energy storage end heat pipe device 7 to monitor in real time whether there is liquid working fluid flowing down and its flow rate.

[0089] Then, controller 4 receives the signal from the flow sensor and performs the following judgment:

[0090] 2-1) If the flow rate is detected to be continuously zero or below a very low threshold, it is determined to be "too low flow rate". The controller 4 immediately sends a command to the heat pipe mode switching pump 15 to increase the pump speed (i.e. flow rate) stepwise or proportionally until a trace amount of liquid is detected again to ensure that the liquid film is completely covered.

[0091] 2-2) If the flow rate is detected to be continuously higher than the set threshold, it is determined to be "excessive flow rate". The controller 4 then sends a command to the pump to gradually reduce its speed (i.e. flow rate) with the goal of reducing the flow rate at the lower end and approaching zero, thereby eliminating liquid waste.

[0092] 2-3) If a slight, intermittent fluctuation in flow rate is detected near the zero threshold, the system is determined to be in or close to the optimal state, and the controller 4 will maintain the current pump speed to achieve stable operation.

[0093] More specifically, such as Figure 3 As shown, an example is provided whereby the controller 4 reads data from the flow sensor 12 and determines the liquid film status. If it is determined that there is excess liquid and the flow rate is greater than the upper limit threshold, then "reduction adjustment" is performed to reduce the pump speed or flow rate. If it is determined that the liquid film is in an optimized state and the flow rate is close to zero, then the current pump speed is maintained to keep the optimal state. If it is determined that the liquid film is insufficient and the flow rate is zero, then "incremental adjustment" is performed to increase the pump speed or flow rate. Subsequently, the controller 4 issues a new command to the variable frequency pump based on the adjustment result, forming a closed-loop control cycle.

[0094] Figure 4 This is a rendering of the invention applied to a 300MW compressed air energy storage power station. After adopting the switchable heat pipe compressed air energy storage heat exchange system and control method of this invention, the overall performance of the compressed air energy storage power station is significantly improved. Through a functionally reversible heat pipe device, the system achieves near-isothermal high-efficiency heat exchange during the compression energy storage stage, increasing the heat exchange efficiency by approximately 6-8 percentage points compared to traditional systems. During the energy release and power generation stage, the heat exchange efficiency is also significantly improved thanks to the excellent heat transfer characteristics of the heat pipe. Simultaneously, the system fundamentally eliminates the traditional circulation loop relying on a high-power working fluid pump, greatly reducing auxiliary power consumption. The comprehensive improvement in heat exchange efficiency and the significant reduction in parasitic power consumption create a synergistic effect, jointly resulting in a significant improvement in the power station's electro-electric efficiency under various load conditions, demonstrating clear advantages over traditional technologies and enhancing the economic viability and market competitiveness of the energy storage power station.

[0095] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A switchable heat pipe compressed air energy storage and heat exchange system, characterized in that, It includes an air switching device, a gas chamber, a gas-end heat pipe device, a phase change liquid storage tank, a heat pipe mode switching pump, an energy storage end heat pipe device, a phase change liquid distribution chamber, a controller, and an energy storage tank. The phase change liquid distribution chamber is connected to the input end of the energy storage end heat pipe device. The air switching device is connected to the compressor, turbine and gas chamber respectively through gas pipelines. The gas end heat pipe device is installed in the gas chamber. The phase change liquid storage tank is connected to the energy storage end heat pipe device through the phase change liquid pipeline. The phase change liquid pipeline is equipped with a heat pipe mode switching pump and a phase change liquid pipeline valve. The phase change liquid storage tank is connected to the gas end heat pipe device through the phase change liquid storage tank valve. The energy storage end heat pipe device is immersed in the heat storage medium in the energy storage tank. The controller is electrically connected to the air switching device, the heat pipe mode switching pump, the phase change liquid pipeline valve, and the phase change liquid storage tank valve. The controller controls the on / off state of the air switching device, the operating state of the heat pipe mode switching pump, and the on / off state of the phase change liquid pipeline valve and the phase change liquid storage tank valve to switch the functions of the evaporation section and condensation section of the gas end heat pipe device and the energy storage end heat pipe device.

2. The switchable heat pipe compressed air energy storage and heat exchange system as described in claim 1, characterized in that, Both the gas-end heat pipe device and the energy storage-end heat pipe device are array-type modular structures, and the number of arrays and modules are adapted according to the heat exchange power.

3. The switchable heat pipe compressed air energy storage and heat exchange system as described in claim 1, characterized in that, Each independent heat pipe of the energy storage end heat pipe device is equipped with an upwardly inclined spiral groove, which allows the phase change liquid to flow along the upwardly inclined spiral groove and exchange heat with the heat storage medium.

4. The switchable heat pipe compressed air energy storage and heat exchange system as described in claim 1, characterized in that, The phase change fluid pipeline valve is connected in series on the pipeline between the gas-end heat pipe device and the energy storage-end heat pipe device, and is used to open and close the phase change fluid flow channel between the gas-end heat pipe device and the energy storage-end heat pipe device; the phase change fluid storage tank valve is connected in series on the pipeline between the gas-end heat pipe device and the heat pipe mode switching pump, and is used to open and close the phase change fluid flow channel between the gas-end heat pipe device and the heat pipe mode switching pump.

5. The switchable heat pipe compressed air energy storage and heat exchange system as described in claim 1, characterized in that, The air switching device is equipped with two sets of control valves. One set of control valves is used to open and close the gas pipeline between the compressor and the air chamber, and the other set of control valves is used to open and close the gas pipeline between the turbine and the air chamber. The two sets of control valves are not in the open state at the same time.

6. A switchable heat pipe compressed air energy storage heat exchange control method, characterized in that, Using the switchable heat pipe compressed air energy storage heat exchange system according to any one of claims 1-5, Includes the following processes: The controller controls the air switching device to open the pipeline between the compressor and the air chamber, close the pipeline between the turbine and the air chamber, open the phase change liquid pipeline valve, and close the phase change liquid storage tank valve. Start the compressor to deliver the high-temperature, high-pressure air formed by compression to the air chamber; The gas end heat pipe device inside the gas cavity absorbs heat from the high-temperature and high-pressure air, causing the internally stored phase change liquid to evaporate into a gas phase. The gaseous phase change liquid flows along the pipeline to the heat pipe device at the energy storage end, where it exchanges heat with the heat storage medium in the energy storage tank and then condenses into a liquid phase. The liquid phase change liquid flows back to the gas end heat pipe device along the pipeline where the phase change liquid pipeline valve is located, completing one heat exchange cycle.

7. The switchable heat pipe compressed air energy storage heat exchange control method as described in claim 6, characterized in that, The controller controls the air switching device to close the pipeline between the compressor and the air chamber, open the pipeline between the turbine and the air chamber, close the phase change liquid pipeline valve, and open the phase change liquid storage tank valve. The low-temperature, high-pressure air from the external gas storage device is delivered to the gas chamber, and the controller simultaneously activates the heat pipe mode switching pump. The heat pipe mode switching pump pumps the phase change liquid in the phase change liquid storage tank to the phase change liquid distribution chamber, and after being evenly distributed by the phase change liquid distribution chamber, it flows into the heat pipe device at the energy storage end. The phase change fluid absorbs heat from the heat storage medium in the energy storage tank within the heat pipe device at the energy storage end and evaporates into a gas phase; The gas phase change liquid flows along the pipeline to the gas end heat pipe device, where it condenses into a liquid phase and releases heat. This heat is used to heat the low-temperature, high-pressure air inside the gas chamber. The liquid phase change fluid flows back to the phase change fluid storage tank along the pipeline where the valve of the phase change fluid storage tank is located, completing one heat exchange cycle; The heated high-pressure air is transported along the pipeline to the turbine, which drives the turbine to run.

8. The switchable heat pipe compressed air energy storage heat exchange control method as described in claim 6, characterized in that, A flow sensor is installed at the lower end of the inclined spiral groove outlet of the energy storage heat pipe device, and the flow sensor is electrically connected to the controller. During the heat exchange process for energy release and power generation, the flow sensor detects the flow rate of the liquid phase change liquid at the outlet of the inclined spiral channel in real time and transmits the detected flow signal to the controller. After receiving the flow signal, the controller makes a judgment and adjusts the speed of the heat pipe mode switching pump: if the detected flow is greater than the set upper limit threshold, the controller controls the heat pipe mode switching pump to reduce the speed. If the detected flow rate is zero, the controller controls the heat pipe mode switching pump to increase its speed; if the detected flow rate fluctuates intermittently near the zero threshold, the controller controls the heat pipe mode switching pump to maintain the current speed.

9. The switchable heat pipe compressed air energy storage heat exchange control method as described in claim 6, characterized in that, The controller monitors the air temperature and pressure in the air chamber, the temperature of the heat storage medium in the energy storage tank, and the air flow rate of the turbine in real time, and adjusts the pump speed of the heat pipe mode switching according to the monitored parameters.

10. The switchable heat pipe compressed air energy storage heat exchange control method as described in claim 6, characterized in that, In the compression and energy storage stage, the circulation channel of the phase change fluid consists of a gas-end heat pipe device, phase change fluid pipeline valves, and an energy storage-end heat pipe device; in the energy release and power generation stage, the circulation channel of the phase change fluid consists of a phase change fluid storage tank, a heat pipe mode switching pump, a phase change fluid distribution chamber, an energy storage-end heat pipe device, a gas-end heat pipe device, and a phase change fluid storage tank valve.

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