Composite heat exchange structure for phase change heat storage

Abstract

This invention discloses a composite heat exchange structure for phase change thermal storage, relating to the field of thermal energy storage and heat exchange technology. It includes: a shell, a heat exchange tube bundle, a state sensing unit, a disturbance mechanism, and a controller. The shell is filled with a phase change material. The heat exchange tube bundle is disposed within the shell for the flow of the heat exchange medium. The state sensing unit is disposed within the shell to acquire the thermal state parameters of the phase change material. The disturbance mechanism applies disturbance to the solidified phase change material layer around the outer wall of the heat exchange tube bundle to disrupt the continuity of the solidified phase change material layer. The disturbance mechanism includes a passive disturbance component and an active disturbance component. The passive disturbance component can automatically perform the disturbance action. The controller is electrically connected to both the state sensing unit and the active disturbance component. When the thermal state parameters acquired by the state sensing unit meet a preset trigger condition, the controller triggers the active disturbance component to perform the disturbance action, which can dynamically disrupt the solidified shell layer or prevent its continuous dense growth, effectively improving the heat exchange efficiency in the later stages of heat release.

Description

Technical Field

[0001] This invention relates to the field of thermal energy storage and heat exchange technology, and in particular to a composite heat exchange structure for phase change thermal storage. Background Technology

[0002] Phase change thermal energy storage technology utilizes the property of phase change materials (PCMs) to absorb or release a large amount of latent heat during solid-liquid phase change, thereby realizing the spatiotemporal redistribution of energy and is an important means to solve the mismatch between thermal energy supply and demand.

[0003] During the exothermic phase, the liquid phase change material gradually solidifies and releases heat. Existing heat exchange structures (such as finned tube bundles, microchannel heat exchangers, and plate heat exchangers) generally suffer from the following unresolved technical defects: First, the increasing thermal resistance effect of the solidified shell. In the later stages of exothermic processes, the phase change material near the heat exchange wall preferentially solidifies and forms a dense solid layer. The thermal conductivity of solid phase change materials is typically only 1 / 3 to 1 / 5 that of the liquid state (e.g., paraffin materials, with a liquid thermal conductivity of about 0.2 W / (m·K) and a solid thermal conductivity of about 0.05 W / (m·K)). This solidified layer becomes the main thermal resistance, severely hindering heat transfer to the heat exchange wall.

[0004] Second, the self-isolation phenomenon of the heat exchange surface. As the solidified layer gradually thickens, the direct contact area between the liquid phase change material and the heat exchange wall approaches zero, and the latent heat release pathway is basically cut off, resulting in a large amount of residual latent heat that cannot be effectively output.

[0005] Third, there is a lack of active intervention mechanisms for the critical state. Existing technologies only passively delay the above process by increasing the number of fins, changing the flow channel geometry, and adding high thermal conductivity fillers (such as foamed metal and expanded graphite), but they cannot actively destroy the thermal resistance layer that has already formed at the solidification critical point. Once the solidified shell is formed, none of the above passive methods can eliminate or reconstruct the heat exchange channels.

[0006] Therefore, there is an urgent need for a composite heat exchange structure that can actively trigger disturbances and reconstruct the heat exchange interface in the solidification critical range in order to solve the technical problem of a sharp drop in heat exchange efficiency in the later stage of heat release. Summary of the Invention

[0007] The purpose of this invention is to provide a composite heat exchange structure for phase change thermal storage to solve the problems existing in the prior art. It can dynamically destroy the solidified shell or prevent its continuous dense growth, effectively improving the heat exchange efficiency in the later stage of heat release.

[0008] To achieve the above objectives, the present invention provides the following solution: This invention provides a composite heat exchange structure for phase change thermal storage, comprising: a shell, a heat exchange tube bundle, a state sensing unit, a disturbance mechanism, and a controller. The shell is filled with a phase change material. The heat exchange tube bundle is disposed inside the shell for the flow of the heat exchange medium. The state sensing unit is disposed inside the shell for acquiring the thermal state parameters of the phase change material. The disturbance mechanism is used to disturb the solidified phase change material layer around the outer wall of the heat exchange tube bundle to disrupt the continuity of the solidified phase change material layer. The disturbance mechanism includes a passive disturbance component and an active disturbance component. The passive disturbance component can automatically perform a disturbance action when the thermal state parameters of the phase change material reach the self-triggering condition of the passive disturbance component. The controller is electrically connected to the state sensing unit and the active disturbance component respectively, so that when the thermal state parameters acquired by the state sensing unit meet the preset triggering condition, the controller triggers the active disturbance component to perform a disturbance action.

[0009] Preferably, the state sensing unit includes an acoustic impedance sensor and a temperature sensor, and the thermal state parameters include the acoustic impedance value and the temperature of the phase change material.

[0010] Preferably, the preset triggering conditions include a first triggering condition and a second triggering condition. The first triggering condition is that the temperature of the phase change material detected by the temperature sensor enters the solidification critical range, and the second triggering condition is that the acoustic impedance value detected by the acoustic impedance sensor reaches the solidification layer densification threshold. When the first triggering condition and the second triggering condition are met simultaneously, the controller determines that the solidified phase change material layer has formed a continuous and dense structure and triggers the active disturbance component to perform a disturbance action.

[0011] Preferably, the solidification critical range is the temperature range between the solidification point temperature and 3°C to 8°C below the solidification point temperature of the phase change material, and the solidification layer density threshold is the acoustic impedance value increasing by 30% to 50% relative to the acoustic impedance value of the fully liquid phase change material.

[0012] Preferably, the passive disturbance component includes shape memory alloy fins, the deformation temperature of which is set within the solidification critical range. When the temperature of the phase change material drops below the deformation temperature, the shape memory alloy fins automatically unfold or twist without being triggered by the controller, so as to physically break the solidified phase change material layer.

[0013] Preferably, the surface of the shape memory alloy fins is provided with a flow guide groove, which is used to guide the broken solid phase change material particles away from the outer wall of the heat exchange tube bundle.

[0014] Preferably, the active disturbance component includes micro-electrothermal elements distributed along the outer wall of the heat exchange tube bundle, and the controller energizes the micro-electrothermal elements in a pulse manner to cause local micro-melting at the interface between the solidified phase change material layer and the outer wall of the heat exchange tube bundle, forming a liquid lubrication interface.

[0015] Preferably, the duty cycle of the pulse mode is 5% to 20%, and the duration of a single power-on is 0.5 seconds to 5 seconds.

[0016] Preferably, the active disturbance component includes a piezoelectric ceramic sheet, which is embedded in the phase change material and disposed adjacent to the heat exchange tube bundle. The controller triggers the piezoelectric ceramic sheet to generate a pressure wave with a frequency of 20Hz to 500Hz and an amplitude of 0.1mm to 1mm.

[0017] Preferably, the outer surface of the heat exchange tube bundle is further provided with a coagulant coating to reduce the adhesion work of the phase change material in the solidification state.

[0018] The present invention achieves the following technical effects compared to the prior art: This invention provides a composite heat exchange structure for phase change thermal storage. By combining a passive disturbance component with an active disturbance mechanism, targeted disturbance actions can be carried out at different stages of the formation of the solidified phase change material layer. In the early stage of the solidification process, the passive disturbance component can automatically break the initial solidified layer after reaching the self-triggering condition, thus slowing down the formation rate of the dense thermal resistance layer. When the passive disturbance is insufficient to prevent the formation of a continuous dense solidified shell, the state sensing unit will collect the thermal state parameters that meet the preset triggering conditions. The controller will then trigger the active disturbance component to further destroy the solidified layer structure and reconstruct the heat exchange interface. This fundamentally solves the problems of high thermal resistance of the solidified shell and self-isolation of the heat exchange surface in the later stage of heat release in traditional phase change thermal storage structures. With only a small increase in structural and control costs, it effectively improves the average heat exchange efficiency of the entire heat release process of the phase change thermal storage device and ensures the stable output capability of the thermal storage system. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the composite heat exchange structure for phase change thermal storage provided by the present invention. Figure 2 This is a side view of the composite heat exchange structure for phase change thermal storage provided by the present invention. Figure 3 A side sectional view of the composite heat exchange structure for phase change thermal storage provided by the present invention; Figure 4 A front sectional view of the composite heat exchange structure for phase change thermal storage provided by the present invention; In the figure: 1. Shell; 11. Medium inlet; 12. Medium outlet; 13. First mounting plate; 14. Second mounting plate; 2. Heat exchange tube bundle; 3. Acoustic impedance sensor; 4. Temperature sensor; 5. Shape memory alloy fins; 6. Miniature electric heating element. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0022] The purpose of this invention is to provide a composite heat exchange structure for phase change thermal storage to solve the problems existing in the prior art. It can dynamically destroy the solidified shell or prevent its continuous dense growth, effectively improving the heat exchange efficiency in the later stage of heat release.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1 This invention provides a composite heat exchange structure for phase change thermal storage, such as... Figures 1-4As shown, the system includes: a shell 1, a heat exchange tube bundle 2, a state sensing unit, a disturbance mechanism, and a controller. The shell 1 is filled with a phase change material. The heat exchange tube bundle 2 is disposed inside the shell 1 for the flow of the heat exchange medium. The state sensing unit is disposed inside the shell 1 for acquiring the thermal state parameters of the phase change material. The disturbance mechanism is used to disturb the solidified phase change material layer around the outer wall of the heat exchange tube bundle 2 to disrupt the continuity of the solidified phase change material layer. The disturbance mechanism includes a passive disturbance component and an active disturbance component. The passive disturbance component can automatically perform a disturbance action when the thermal state parameters of the phase change material reach the self-triggering condition of the passive disturbance component. The controller is electrically connected to the state sensing unit and the active disturbance component respectively, so that when the thermal state parameters acquired by the state sensing unit meet the preset triggering condition, the controller triggers the active disturbance component to perform a disturbance. The system, through the cooperation of passive disturbance components and active disturbance mechanisms, can carry out targeted disturbance actions at different stages of the formation of the solidified phase change material layer: In the early stage of the solidification process, once the self-triggering condition is met, the passive disturbance component can automatically break the initial solidified layer, slowing down the formation rate of the dense thermal resistance layer; when the passive disturbance is insufficient to prevent the formation of a continuous dense solidified shell, the state sensing unit will collect the thermal state parameters that meet the preset triggering condition, and the controller will trigger the active disturbance component to further destroy the solidified layer structure and reconstruct the heat exchange interface. This fundamentally solves the problems of high thermal resistance of the solidified shell and self-isolation of the heat exchange surface in the later stage of heat release in traditional phase change thermal storage structures. With only a small increase in structural and control costs, it effectively improves the average heat exchange efficiency of the entire heat release process of the phase change thermal storage device and ensures the stable output capability of the thermal storage system.

[0025] In a preferred embodiment, the state sensing unit includes an acoustic impedance sensor 3 and a temperature sensor 4. The thermal state parameters include the acoustic impedance value and the temperature of the phase change material. By combining the acoustic impedance sensor 3 and the temperature sensor 4, the thermal state parameters of the phase change material can be accurately obtained from different dimensions. The acoustic impedance value reflects the changes in the internal structure of the phase change material, while the temperature directly reflects its thermal state. The combination of the two provides comprehensive data support for the subsequent accurate determination of the state of the solidified phase change material layer, which helps to more accurately trigger the disturbance mechanism and improve the system's monitoring and control capabilities for the phase change process.

[0026] In a preferred embodiment, the preset triggering conditions include a first triggering condition and a second triggering condition. The first triggering condition is that the temperature of the phase change material detected by the temperature sensor 4 enters the solidification critical range, and the second triggering condition is that the acoustic impedance value detected by the acoustic impedance sensor 3 reaches the solidification layer densification threshold. When both the first and second triggering conditions are met simultaneously, the controller determines that the solidified phase change material layer has formed a continuous and dense structure and triggers the active disturbance component to perform a disturbance action. Setting dual preset triggering conditions makes the judgment of the formation of a continuous and dense structure in the solidified phase change material layer more accurate and reliable. The active disturbance component is only triggered when the two key parameters, temperature and acoustic impedance value, meet their respective conditions, avoiding false triggering and ensuring that active disturbance is initiated in time when the solidified phase change material layer truly forms a continuous and dense structure that hinders heat transfer, effectively improving the system's stability and heat transfer efficiency.

[0027] In a preferred embodiment, the solidification critical range is the temperature range between the phase change material's freezing point and 3°C to 8°C below that freezing point. The solidification layer densification threshold is defined as an increase in acoustic impedance value of 30% to 50% relative to that of a fully liquid phase change material. Based on the characteristics of the phase change material, the solidification critical range and solidification layer densification threshold are precisely defined, providing a quantitative standard for judging the state of the solidified phase change material layer. This quantitative standard enables the system to accurately identify and react before the phase change material forms a continuous, dense solidified layer that severely affects heat transfer, triggering a disturbance mechanism in a timely manner. This, in turn, more effectively maintains a good heat transfer state and improves heat transfer efficiency in the later stages of exothermic processes.

[0028] In a preferred embodiment, the passive disturbance component includes shape memory alloy fins 5. The deformation temperature of these fins is set within the solidification critical range. When the temperature of the phase change material drops below the deformation temperature, the shape memory alloy fins 5 automatically unfold or twist without controller triggering, physically breaking the solidified phase change material layer. As a passive disturbance component, the shape memory alloy fins 5 utilize their automatic deformation characteristic at a specific temperature to actively break the solidified phase change material layer when the temperature drops to a suitable range without additional control. This not only provides a reliable pre-action mechanism for breaking the solidified layer, reducing the burden on the active disturbance component, but also allows for a certain degree of damage to the solidified layer before the controller triggers active disturbance, helping to maintain better heat exchange conditions and improve overall heat exchange efficiency.

[0029] In a preferred embodiment, the surface of the shape memory alloy fins 5 is provided with guide grooves. These grooves guide the broken solid phase change material particles away from the outer wall of the heat exchange tube bundle 2. The design of the guide grooves can guide the broken solid phase change material particles away from the outer wall of the heat exchange tube bundle 2, preventing these particles from re-attaching to the heat exchange tube bundle 2 and forming structures that affect heat exchange again. In this way, good heat exchange conditions are further ensured on the outer wall of the heat exchange tube bundle 2, the destructive effect on the solidified phase change material layer is enhanced, heat exchange efficiency is continuously improved, and the working pressure of the subsequent active disturbance mechanism to clean the attached particles is reduced.

[0030] In a preferred embodiment, the active disturbance component includes micro-thermal elements 6 distributed along the outer wall of the heat exchange tube bundle 2. The controller energizes the micro-thermal elements 6 in a pulsed manner, causing localized micro-melting at the interface between the solidified phase change material layer and the outer wall of the heat exchange tube bundle 2, forming a liquid lubrication interface. The micro-thermal elements 6, through pulsed energization, form this liquid lubrication interface at the interface between the solidified phase change material layer and the outer wall of the heat exchange tube bundle 2. This method softens and disrupts the bond between the solidified layer and the heat exchange tube bundle 2, further breaking the continuity of the solidified layer and enhancing the destructive effect. Compared to a single physical fragmentation method, this thermal disturbance method improves the heat exchange interface from another perspective, effectively increasing the heat exchange efficiency in the later stages of exothermic processes. Furthermore, the pulsed energization method allows for precise control of energy input, avoiding overheating that could adversely affect the system.

[0031] In a preferred embodiment, the duty cycle of the pulse mode is 5% to 20%, and the duration of a single energization is 0.5 to 5 seconds. Precisely setting the duty cycle and duration of the pulse mode allows for effective formation of the liquid lubrication interface and disruption of the solidified layer while rationally controlling energy consumption. This parameter setting avoids excessive energy loss while ensuring the perturbation effect of the micro-heating element 6 on the solidified layer, achieving a highly efficient and energy-saving operating mode and improving the overall performance and economic efficiency of the system.

[0032] In a preferred embodiment, the active disturbance component includes a piezoelectric ceramic sheet embedded in the phase change material and positioned adjacent to the heat exchange tube bundle 2. The controller triggers the piezoelectric ceramic sheet to generate a pressure wave with a frequency of 20Hz to 500Hz and an amplitude of 0.1mm to 1mm. This pressure wave can disturb the solidified phase change material layer from within, further disrupting its structural density. By generating pressure waves within a specific frequency and amplitude range, it can be combined with other disturbance methods to disrupt the solidified layer from different angles and in all directions, enhancing the disturbance effect on the solidified phase change material layer, effectively improving heat exchange efficiency. Furthermore, the parameters can be flexibly adjusted within this frequency and amplitude range according to different phase change material characteristics and operating conditions, improving the system's adaptability.

[0033] In a preferred embodiment, the outer surface of the heat exchange tube bundle 2 is further provided with a solidification coating to reduce the adhesion work of the phase change material in the solidified state. The solidification coating reduces the adhesion force of the phase change material to the outer wall of the heat exchange tube bundle 2 in the solidified state, making the solidified phase change material layer easier to be destroyed and removed by the active disturbance mechanism. This reduces the adhesion of the solidified layer to the outer wall of the heat exchange tube bundle 2, helps to maintain a good heat exchange interface, further improves heat exchange efficiency, and can reduce the workload of the active disturbance mechanism and extend its service life.

[0034] In a preferred embodiment, the temperature sensor 4 is a multi-point distributed sensor array consisting of multiple temperature sensors 4 distributed along the axial and circumferential directions of the heat exchange tube bundle 2. The multi-point distributed sensor array can comprehensively and accurately detect the temperature distribution of the phase change material around the heat exchange tube bundle 2, providing the controller with more detailed and accurate temperature data. This enables the controller to more accurately determine the solidification state of the phase change material, thereby triggering the active disturbance mechanism more precisely. This ensures that the system can intervene in a timely and effective manner under different locations and operating conditions, improving the heat exchange efficiency and stability of the entire system.

[0035] In a preferred embodiment, the shell 1 has a medium inlet 11 and a medium outlet 12 at its two ends, respectively. The shell 1 has a first mounting plate 13 and a second mounting plate 14 at its two ends, respectively. The two ends of each heat exchange tube bundle 2 are mounted on the first mounting plate 13 and the second mounting plate 14, respectively. The phase change material is encapsulated in the cavity of the first mounting plate 13 and the second mounting plate 14. A flow equalization cavity is formed between the first mounting plate 13 and the medium inlet 11, and a flow collection cavity is formed between the second mounting plate 14 and the medium outlet 12. After the heat exchange medium enters the flow equalization cavity from the medium inlet 11, it can be evenly distributed to each heat exchange tube bundle 2 through the flow equalization cavity, so that the flow rate of the heat exchange medium in each heat exchange tube bundle 2 is evenly distributed, avoiding the situation of excessive or insufficient local flow, ensuring uniform heat exchange in each heat exchange area. Finally, the heat exchanged medium flows out from the medium outlet 12 after flowing into the flow collection cavity, ensuring that the entire heat exchange process is smooth and stable, and improving the overall heat exchange uniformity and effectiveness.

[0036] The following are the usage instructions for the above-mentioned composite heat exchange structure used for phase change thermal storage: 1. System Preparation: Installation and Filling: Place the housing 1 in a suitable position, ensuring smooth connection with the external heat exchange medium delivery system through the medium inlet 11 and medium outlet 12. Fill the housing 1 with phase change material, and install the two ends of the heat exchange tube bundle 2 on the first mounting plate 13 and the second mounting plate 14 respectively, so that the heat exchange tube bundle 2 is stably set inside the housing 1. At the same time, install the state sensing unit (acoustic impedance sensor 3 and multi-point distributed temperature sensor array 4) in a suitable position inside the housing 1 to accurately obtain the thermal state parameters of the phase change material; install the passive disturbance component (shape memory alloy fins 5) around the outer wall of the heat exchange tube bundle 2, and arrange the active disturbance component (micro-thermal element 6, piezoelectric ceramic sheet) in the corresponding position according to the design requirements to ensure normal electrical connection between the controller and the state sensing unit and the active disturbance component.

[0037] Parameter settings: Based on the characteristics of the phase change material used, set the solidification critical range (the temperature of the phase change material is between its solidification point temperature and 3°C to 8°C below that solidification point temperature) and the solidification layer density threshold (the acoustic impedance value increases by 30% to 50% relative to the acoustic impedance value of the completely liquid phase change material). At the same time, set the duty cycle (5% to 20%), single energization duration (0.5 seconds to 5 seconds), and the frequency (20Hz to 500Hz) and amplitude (0.1mm to 1mm) of the pressure wave generated by the piezoelectric ceramic sheet.

[0038] 2. Phase change thermal energy storage operation: Heat exchange medium flow: The external heat exchange medium delivery system is activated, and the heat exchange medium flows in from the medium inlet 11, first entering the flow equalization chamber. Under the action of the flow equalization chamber, the heat exchange medium is evenly distributed into each heat exchange tube bundle 2, ensuring that the flow rate of the heat exchange medium in each heat exchange tube bundle 2 is uniform. Then, it flows in the heat exchange tube bundle 2, exchanges heat with the phase change material in the shell 1, and finally the heat-exchanged medium flows into the collection chamber and then flows out from the medium outlet 12.

[0039] Condition monitoring: During the heat exchange process, the condition sensing unit operates in real time. The multi-point distributed temperature sensor array 4 comprehensively and accurately detects the temperature distribution of the phase change material around the heat exchange tube bundle 2, and the acoustic impedance sensor 3 acquires the acoustic impedance value of the phase change material in real time. These thermal state parameters are transmitted to the controller in real time.

[0040] Passive disturbance: When the temperature of the phase change material drops and reaches the deformation temperature of the shape memory alloy fin 5 (set within the solidification critical range), the shape memory alloy fin 5 automatically unfolds or twists without controller triggering, physically breaking up the nascent solidified phase change material layer and slowing down the formation rate of the dense thermal resistance layer. At the same time, the guide grooves on the surface of the shape memory alloy fin 5 guide the broken solid phase change material particles away from the outer wall of the heat exchange tube bundle 2, preventing them from re-adhering and affecting heat exchange.

[0041] Active disturbance: As the exothermic process proceeds, if the passive disturbance is insufficient to prevent the formation of a continuous and dense solidified shell, when the temperature sensor 4 detects that the phase change material temperature has entered the solidification critical range, and the acoustic impedance sensor 3 detects that the acoustic impedance value has reached the solidification layer density threshold, the preset triggering condition is met. The controller determines that the solidified phase change material layer has formed a continuous and dense structure and triggers the active disturbance component to operate.

[0042] Miniature heating element 6: The controller energizes the miniature heating element 6 distributed along the outer wall of the heat exchange tube bundle 2 in a set pulse mode (duty cycle 5% to 20%, single energizing time 0.5 seconds to 5 seconds), causing local micro-melting at the interface between the solidified phase change material layer and the outer wall of the heat exchange tube bundle 2, forming a liquid lubrication interface, softening and destroying the bonding part between the solidified layer and the heat exchange tube bundle 2, and further breaking the continuity of the solidified layer.

[0043] Piezoelectric ceramic sheet: Simultaneously, the controller triggers the piezoelectric ceramic sheet embedded in the phase change material and located near the heat exchange tube bundle 2 to generate a pressure wave with a frequency of 20Hz to 500Hz and an amplitude of 0.1mm to 1mm. This wave disturbs the solidified phase change material layer from the inside, destroying its structural compactness. In conjunction with the action of the micro-heating element 6, it destroys the solidified layer from all directions and reconstructs the heat exchange interface.

[0044] 3. Continuous monitoring and adjustment: Throughout the phase change thermal storage process, the state sensing unit continuously monitors the thermal state parameters of the phase change material. Based on these parameters, the controller determines in real time whether the active disturbance component needs to be triggered again to maintain a good heat exchange state. Simultaneously, the solidification coating continues to function, reducing the adhesion force of the phase change material to the outer wall of the heat exchange tube bundle 2 in its solidified state. This makes the solidified phase change material layer easier to break down and remove by the active disturbance mechanism, reducing the adhesion of the solidified layer to the outer wall of the heat exchange tube bundle 2, further improving heat exchange efficiency, reducing the workload of the active disturbance mechanism, and extending its service life.

[0045] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A composite heat exchange structure for phase change thermal storage, characterized in that, include: A housing, the interior of which is filled with a phase change material; A heat exchange tube bundle is disposed inside the shell and is used for the flow of heat exchange medium; A state sensing unit is disposed inside the housing and is used to acquire the thermal state parameters of the phase change material; A disturbance mechanism is provided to apply disturbance to the solidified phase change material layer around the outer wall of the heat exchange tube bundle in order to disrupt the continuity of the solidified phase change material layer. The disturbance mechanism includes a passive disturbance component and an active disturbance component. The passive disturbance component can automatically perform a disturbance action when the thermal state parameters of the phase change material reach the self-triggering condition of the passive disturbance component. The controller is electrically connected to the state sensing unit and the active disturbance component, respectively, so that when the thermal state parameters obtained by the state sensing unit meet the preset triggering conditions, the controller triggers the active disturbance component to perform a disturbance action.

2. The composite heat exchange structure for phase change thermal storage according to claim 1, characterized in that: The state sensing unit includes an acoustic impedance sensor and a temperature sensor, and the thermal state parameters include the acoustic impedance value and the temperature of the phase change material.

3. The composite heat exchange structure for phase change thermal storage according to claim 2, characterized in that: The preset triggering conditions include a first triggering condition and a second triggering condition. The first triggering condition is that the temperature of the phase change material detected by the temperature sensor enters the solidification critical range, and the second triggering condition is that the acoustic impedance value detected by the acoustic impedance sensor reaches the solidification layer density threshold. When the first triggering condition and the second triggering condition are met simultaneously, the controller determines that the solidified phase change material layer has formed a continuous and dense structure and triggers the active disturbance component to perform a disturbance action.

4. The composite heat exchange structure for phase change thermal storage according to claim 3, characterized in that: The solidification critical range is the temperature range between the solidification point temperature and 3°C to 8°C below the solidification point temperature of the phase change material, and the solidification layer density threshold is the acoustic impedance value increasing by 30% to 50% relative to the acoustic impedance value of the fully liquid phase change material.

5. The composite heat exchange structure for phase change thermal storage according to claim 3, characterized in that: The passive disturbance component includes shape memory alloy fins, the deformation temperature of which is set within the solidification critical range. When the temperature of the phase change material drops below the deformation temperature, the shape memory alloy fins automatically unfold or twist without being triggered by the controller, so as to physically break the solidified phase change material layer.

6. The composite heat exchange structure for phase change thermal storage according to claim 5, characterized in that: The surface of the shape memory alloy fins is provided with flow guide grooves, which are used to guide the broken solid phase change material particles away from the outer wall of the heat exchange tube bundle.

7. The composite heat exchange structure for phase change thermal storage according to claim 3, characterized in that: The active disturbance component includes micro-electrothermal elements distributed along the outer wall of the heat exchange tube bundle. The controller energizes the micro-electrothermal elements in a pulse manner, causing local micro-melting at the interface between the solidified phase change material layer and the outer wall of the heat exchange tube bundle, forming a liquid lubrication interface.

8. The composite heat exchange structure for phase change thermal storage according to claim 7, characterized in that: The pulse mode has a duty cycle of 5% to 20% and a single power-on duration of 0.5 to 5 seconds.

9. The composite heat exchange structure for phase change thermal storage according to claim 3, characterized in that: The active disturbance component includes a piezoelectric ceramic sheet embedded in the phase change material and disposed adjacent to the heat exchange tube bundle. The controller triggers the piezoelectric ceramic sheet to generate a pressure wave with a frequency of 20Hz to 500Hz and an amplitude of 0.1mm to 1mm.

10. The composite heat exchange structure for phase change thermal storage according to claim 1, characterized in that: The outer surface of the heat exchange tube bundle is also provided with a coagulant coating to reduce the adhesion work of the phase change material in the solidification state.

Images