A dual-condenser adaptive loop heat pipe heat dissipation system and heat dissipation control method

Abstract

The application discloses a double-condenser adaptive loop heat pipe heat dissipation system, a heat dissipation control method and a water energy storage system, and belongs to the technical field of electrochemical energy storage systems. The heat dissipation system comprises an evaporator, a steam pipeline, a first condenser, a second condenser, a liquid pipeline and a control unit. The evaporator is attached to the heat exchange surface of an energy storage battery pack, and a capillary core structure is arranged in the evaporator. The inlet of the steam pipeline is in sealed communication with the steam outlet of the evaporator. The first condenser is immersed in water, and the steam inlet of the first condenser is in communication with the outlet of the steam pipeline. The second condenser is arranged in air above the water surface, and the steam inlet of the second condenser is in communication with the outlet of the steam pipeline. The inlets of the liquid pipeline are respectively in communication with the liquid outlets of the first condenser and the second condenser, and the outlet extends upward to the liquid inlet of the evaporator to form a closed circulation loop with the evaporator. The circulation loop is filled with a phase change working medium.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage system technology, and more specifically, to a dual-condenser adaptive loop heat pipe heat dissipation system, a heat dissipation control method, and a floating energy storage system. Background Technology

[0002] Floating photovoltaic (PV) power plants with distributed energy storage are an important solution for addressing power output fluctuations and improving plant profitability. However, due to space constraints in water areas, traditional centralized large-scale energy storage equipment is difficult to deploy. Therefore, distributed energy storage has become the mainstream solution for floating PV power plants with distributed energy storage. This involves distributing lithium iron phosphate (LFP) battery clusters or packs in suitable locations on the water surface or hanging them on PV support columns, effectively overcoming the problem of limited water space. However, this installation method is limited by the special operating conditions on the water surface, and the heat dissipation of the battery packs becomes a key factor restricting the stable operation of the system.

[0003] The applicant previously proposed a loop heat pipe cooling system for a floating energy storage battery pack (application number: 202610767234.1), in which the evaporator is attached to the surface of the battery pack, and the working fluid vapor is transported downwards through pipelines to a condenser submerged in water for condensation, achieving pump-free cooling with the heat source above and the cold source below. However, this solution still has the following technical defects in practical applications: (1) In hot summer weather, the surface water temperature rises, the temperature difference between the underwater condenser and the water decreases, the heat dissipation efficiency drops significantly, which may lead to uncontrolled battery pack temperature. (2) In waters with large water level fluctuations, fixed underwater condensers may be partially or completely exposed above the water surface, losing their heat dissipation function; (3) A single underwater condenser lacks redundant heat dissipation paths. When the efficiency of the condenser decreases due to biological attachment or siltation, the system lacks a backup heat dissipation scheme.

[0004] Therefore, in the context of floating energy storage, how to enhance heat dissipation capacity under high-temperature conditions, provide redundant heat dissipation paths, and adapt to water level changes and water temperature fluctuations while retaining the advantages of pump-free and maintenance-free loop heat pipes is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-condenser adaptive loop heat pipe heat dissipation system, a heat dissipation control method, and a floating energy storage system, which can solve the technical problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention is implemented as follows: In a first aspect, the present invention provides a dual-condenser adaptive loop heat pipe heat dissipation system, comprising: an evaporator, a steam pipeline, a first condenser, a second condenser, a liquid pipeline, and a control unit; The evaporator is fitted onto the heat exchange surface of the energy storage battery pack, and the evaporator has a capillary wick structure inside. The inlet of the steam pipeline is sealed and connected to the steam outlet of the evaporator, and the outlet extends downward. The first condenser is submerged in water, and the steam inlet of the first condenser is connected to the outlet of the steam pipeline; The second condenser is located in the air above the water surface, and the steam inlet of the second condenser is connected to the outlet of the steam pipeline; The inlet of the liquid pipeline is connected to the liquid outlet of the first condenser and the liquid outlet of the second condenser, respectively, and the outlet extends upward to the liquid inlet of the evaporator, forming a closed loop with the evaporator; The circulation loop is filled with a phase change working fluid, and the capillary force generated by the capillary wick structure drives the working fluid to circulate. The control unit is configured to adjust the steam flow rate entering the first condenser and / or the second condenser based on at least one of the parameters of battery pack temperature, water temperature and ambient temperature, so as to switch between single condenser heat dissipation mode and dual condenser collaborative heat dissipation mode.

[0007] Furthermore, the outlet end of the steam pipeline is provided with a three-way valve or a distributor, the first outlet of the three-way valve or the distributor is connected to the first condenser, and the second outlet is connected to the second condenser; the control unit is electrically connected to the three-way valve or the distributor and is used to control the steam distribution ratio.

[0008] Furthermore, the steam pipeline includes a main steam pipe, a first branch pipe and a second branch pipe, the first branch pipe being connected to the first condenser and the second branch pipe being connected to the second condenser; the first branch pipe and / or the second branch pipe are equipped with a one-way valve or a heat-driven valve driven by steam pressure to achieve passive distribution of steam flow.

[0009] Furthermore, the control unit is configured as follows: When the battery pack temperature is lower than the first preset temperature threshold, control steam to enter only the first condenser; When the battery pack temperature is higher than the first preset temperature threshold and the water temperature is lower than the second preset temperature threshold, the control steam will only enter the first condenser. When the battery pack temperature is higher than the first preset temperature threshold and the water temperature is higher than the second preset temperature threshold, steam is controlled to enter the first condenser and the second condenser simultaneously. When the water temperature is higher than the second preset temperature threshold and the ambient temperature is lower than the third preset temperature threshold, the steam distribution ratio of the second condenser is increased.

[0010] Furthermore, the second condenser is a finned tube air-cooled heat exchanger. The second condenser is installed on the upper part of the water surface photovoltaic support column or on the back of the photovoltaic module, and heat dissipation is achieved by natural convection or forced airflow on the back of the photovoltaic module. The installation height of the second condenser is not lower than the installation height of the evaporator, so that the condensate in the second condenser can flow back to the evaporator by gravity.

[0011] Furthermore, the liquid outlets of the first and second condensers are connected to the liquid pipeline via a manifold, and a one-way valve is installed in the manifold to prevent backflow of condensate.

[0012] Furthermore, a phase change material layer is provided between the evaporator and the energy storage battery pack to absorb instantaneous heat spikes.

[0013] Furthermore, the system is provided with multiple evaporators, the steam outlets of the multiple evaporators are connected in parallel to the steam pipeline, the liquid inlets of the multiple evaporators are connected in parallel to the liquid pipeline, and they share the first condenser and the second condenser.

[0014] Secondly, the present invention provides a heat dissipation control method applied to the aforementioned dual-condenser adaptive loop heat pipe heat dissipation system, comprising: Real-time acquisition of battery pack temperature Tb, water temperature Tw, and ambient temperature Ta; When Tb≤T1, control steam only enters the first condenser, and the system operates in underwater single condenser mode. When Tb>T1 and Tw≤T2, control the steam to enter only the first condenser; When Tb>T1 and Tw>T2, control steam enters the first condenser and the second condenser simultaneously, and the system operates in dual-condenser cooperative mode. Wherein, T1 is the first preset temperature threshold and T2 is the second preset temperature threshold.

[0015] Thirdly, the present invention provides an aquatic energy storage system, including a surface photovoltaic module, a photovoltaic support column, an energy storage battery pack, and the aforementioned dual-condenser adaptive loop heat pipe heat dissipation system.

[0016] The above technical solution has at least the following advantages compared with the existing technology: (1) In this embodiment of the invention, when the water temperature rises and the heat dissipation capacity decreases in summer, the second condenser (air condenser) serves as a supplementary heat dissipation path, working in conjunction with the first condenser to significantly improve the system's peak heat dissipation capacity and prevent the battery pack from overheating. Compared with the single underwater condenser solution, the heat dissipation capacity of this invention is improved in high-temperature environments.

[0017] (2) In this embodiment of the invention, when the underwater condenser fails due to reasons such as water level drop, biological attachment, siltation, or icing, the system can automatically switch to the air condenser to continue operation, thus avoiding complete paralysis of the heat dissipation system. This redundancy design is of great value for unattended underwater energy storage scenarios, and reliability can be improved through redundant heat dissipation paths.

[0018] (3) In this embodiment of the invention, the control unit automatically selects a single condenser mode or a dual condenser coordinated mode based on parameters such as battery temperature, water temperature, and ambient temperature. In winter or low-temperature water conditions, water heat dissipation is prioritized (high efficiency and zero energy consumption), while in summer or high-temperature water conditions, air-assisted heat dissipation is activated to achieve the optimal energy efficiency ratio throughout the year.

[0019] (4) In this embodiment of the invention, when the water level drops and the first condenser is exposed above the water surface, the system can automatically switch to the second condenser to work, which solves the failure problem of the fixed underwater condenser under water level fluctuation conditions and expands the applicable water area of ​​the system. Attached Figure Description

[0020] The accompanying drawings, which form part of this specification, 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 undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of a dual-condenser adaptive loop heat pipe cooling system provided in an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of a preferred structure for adding a phase change material layer between the evaporator and the battery pack, provided by an embodiment of the present invention.

[0022] Reference numerals: 1-Photovoltaic module; 2-Support column; 3-Triangular bracket; 4-Energy storage battery pack; 5-Evaporator; 6-Three-way valve; 7-First steam branch; 8-Second steam branch; 9-First condenser; 10-Second condenser; 11-Liquid pipeline; 12-Electric three-way valve. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0024] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this invention is for describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0025] Example 1 like Figure 1 and 2 As shown, this embodiment provides a dual-condenser adaptive loop heat pipe cooling system for an aquatic energy storage battery pack, including an evaporator 5, steam pipelines (first branch pipe 7, second branch pipe 8), a first condenser 9, a second condenser 10, a liquid pipeline 11, and a control unit.

[0026] Support column 2 is vertically fixed in the water, and photovoltaic module 1 is installed on top of support column 2. Energy storage battery pack 4 is fixed to the middle of support column 2 via triangular bracket 3, located above the water surface. Evaporator 5 is a flat-plate loop heat pipe evaporator with an internal capillary structure (sintered metal powder capillary core), which is fitted to the heat exchange surface of energy storage battery pack 4. The steam outlet of evaporator 5 is sealed and connected to the inlet of the steam pipeline.

[0027] The steam pipeline is split into two branches via a three-way valve 6 or a distributor: the first branch 7 extends downwards below the water surface and connects to the steam inlet of the first condenser 9. The second branch extends and connects to the steam inlet of the second condenser 10. The first condenser 9 is a finned-tube heat exchanger, submerged in water at a depth of 1.5 meters below the water surface. The second condenser 10 is a finned-tube air-cooled heat exchanger, installed on the upper part or side of the support column 2, positioned in the air above the water surface, below the back of the photovoltaic module 1, utilizing natural convection or forced airflow from the back of the photovoltaic module for heat dissipation. The installation height of the second condenser is not lower than that of the evaporator, allowing the condensate in the second condenser to flow back to the evaporator by gravity.

[0028] The liquid outlets of the first condenser 9 and the second condenser 10 are connected to the liquid line 11 via a manifold. The liquid line 11 is connected to the liquid inlet of the evaporator 5, forming a closed loop. A one-way valve is installed in the manifold to prevent backflow of condensate. The loop is filled with a phase change working fluid, and the capillary force generated by the capillary wick structure drives the working fluid to circulate.

[0029] The control unit is configured to adjust the steam flow rate into the first condenser and / or the second condenser based on at least one of the parameters of battery pack temperature, water temperature and ambient temperature, so as to switch between single condenser heat dissipation mode and dual condenser synergistic heat dissipation mode.

[0030] In this embodiment, steam distribution adopts a passive method: the diameter, length, and resistance of the first and second branch pipes are matched and designed so that steam preferentially enters the first condenser 9 under normal operating conditions. When the condensing pressure of the first condenser 9 increases due to the rise in water temperature, steam is automatically diverted to the second condenser 10, achieving passive self-adaptation. The system requires no external power supply or control unit, relying entirely on physical characteristics to achieve the coordinated operation of the two condensers.

[0031] The working process of this embodiment is as follows: The energy storage battery pack 4 generates heat through charging and discharging, which is transferred to the evaporator 5. The working fluid in the evaporator 5 absorbs heat and vaporizes, and the steam is transported outward along the steam pipeline. After being diverted by a three-way valve, the steam is distributed according to the resistance of the two branches, with part entering the first condenser 9 and part entering the second condenser 10. The steam exchanges heat with water or air in the two condensers respectively, condensing into liquid. The condensed liquid flows back to the evaporator 5 through the liquid pipeline 11, completing the cycle. When the water temperature is low, the first condenser 9 has high condensation efficiency, and most of the steam enters it. When the water temperature rises and the condensation efficiency decreases, the second condenser 10 takes on more steam flow, ensuring the overall heat dissipation capacity of the system.

[0032] Furthermore, a phase change material layer is provided between the evaporator 5 and the energy storage battery pack 4 to absorb instantaneous heat spikes.

[0033] Furthermore, the system is equipped with multiple evaporators 5, the steam outlets of the multiple evaporators 5 are connected in parallel to the steam pipeline, and the liquid inlets of the multiple evaporators 5 are connected in parallel to the liquid pipeline 11, sharing the first condenser 9 and the second condenser 10.

[0034] The working principle of this invention is as follows: Under normal operating conditions (sufficient water cooling capacity): When the temperature of the energy storage battery pack 4 is low or the water temperature is low, the control unit directs all the steam into the first condenser 9 (underwater condenser). After exchanging heat with the low-temperature water, the steam condenses into liquid and flows back to the evaporator 5 under capillary action. The system operates in the same way as a conventional single-condenser loop heat pipe, achieving zero energy consumption and maintenance-free heat dissipation.

[0035] High-temperature operation (insufficient water heat dissipation): When the temperature of the energy storage battery pack 4 rises and the water temperature exceeds the set threshold, the control unit distributes some or all of the steam to the second condenser 10 (air condenser), or simultaneously to both condensers. The steam exchanges heat with the air in the second condenser 10, utilizing natural or forced convection to dissipate heat and supplement the insufficient heat dissipation capacity of the water.

[0036] Water level drop or condenser failure: When the first condenser 9 is exposed above the water surface due to water level drop or biological attachment, resulting in a decrease in heat dissipation efficiency, the system can automatically switch to the second condenser 10 as the main heat dissipation path to ensure the continuous operation of the heat dissipation system and provide redundant protection.

[0037] Adaptive switching: The control unit dynamically adjusts the steam distribution ratio by monitoring the battery pack temperature, water temperature and ambient temperature in real time, so that the system always works in the optimal heat dissipation mode, taking into account energy consumption, heat dissipation capacity and reliability.

[0038] Example 2 like Figure 2 As shown, this embodiment adds an active control function based on embodiment 1. An electric three-way valve 12 is installed at the outlet end of the steam pipeline. The steam inlets of the first condenser 9 and the second condenser 10 are respectively connected to the two outlets of the three-way valve 12. The control unit 13 is connected to the three-way valve 12 and the system temperature sensors. The system temperature sensors include a battery temperature sensor Tb integrated into the energy storage battery pack 4, a water temperature sensor Tw attached to the surface of the first condenser, and an ambient temperature sensor Ta located in the environment.

[0039] The control unit 13 has built-in control logic. The first preset temperature threshold is Tb = 35℃ (battery pack high-temperature threshold), and the second preset temperature threshold is Tw = 25℃ (water high-temperature threshold). The control unit 13 collects data from each temperature sensor in real time and controls the three-way valve 12 according to the following logic: When Tb≤ 35℃, control the three-way valve 11 to allow all steam to enter the first condenser 7 (single underwater mode).

[0040] When Tb>35℃ and Tw≤25℃, control the three-way valve 11 to allow all steam to enter the first condenser 9.

[0041] When Tb>35℃ and Tb>25℃, control the three-way valve 11 to allow steam to enter the first condenser 7 and the second condenser 8 simultaneously in proportion (e.g., 50%:50%) (dual condenser cooperative mode).

[0042] When Tb>25℃ and Ta<20℃, the control unit 13 can preferentially increase the allocation ratio of the second condenser 10 to enhance heat dissipation by utilizing the low-temperature ambient air.

[0043] In this embodiment, the power supply for the control unit 13 can be directly provided by the photovoltaic module 1 (DC 12V / 24V), with extremely low power consumption (<1W). The three-way valve 12 adopts a low-power electric ball valve or a shape memory alloy thermally driven valve to further reduce energy consumption.

[0044] Compared to Example 1, this embodiment achieves more accurate operating condition identification and active adjustment, and the heat dissipation system is more adaptable to different environments while still maintaining extremely low energy consumption (only the control unit and the three-way valve consume power).

[0045] Example 3 This embodiment provides a dual-condenser heat dissipation system for scenarios with multiple battery packs and multiple support columns. Multiple support columns 2 are arranged in an array in the water, and multiple battery packs can share a single second condenser.

[0046] Example 4 This embodiment provides a floating energy storage system. It includes surface photovoltaic modules, photovoltaic support columns, an energy storage battery pack, and the dual-condenser adaptive loop heat pipe cooling system described in the previous embodiment.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A dual-condenser adaptive loop heat pipe cooling system, characterized in that, include: Evaporator, steam line, first condenser, second condenser, liquid line, and control unit; The evaporator is fitted onto the heat exchange surface of the energy storage battery pack, and the evaporator has a capillary wick structure inside. The inlet of the steam pipeline is sealed and connected to the steam outlet of the evaporator, and the outlet extends downward. The first condenser is submerged in water, and the steam inlet of the first condenser is connected to the outlet of the steam pipeline; The second condenser is located in the air above the water surface, and the steam inlet of the second condenser is connected to the outlet of the steam pipeline; The inlet of the liquid pipeline is connected to the liquid outlet of the first condenser and the liquid outlet of the second condenser, respectively, and the outlet extends upward to the liquid inlet of the evaporator, forming a closed loop with the evaporator; The circulation loop is filled with a phase change working fluid, and the capillary force generated by the capillary wick structure drives the working fluid to circulate. The control unit is configured to adjust the steam flow rate entering the first condenser and / or the second condenser based on at least one of the parameters of battery pack temperature, water temperature and ambient temperature, so as to switch between single condenser heat dissipation mode and dual condenser collaborative heat dissipation mode.

2. The dual-condenser adaptive loop heat pipe cooling system according to claim 1, characterized in that, The outlet end of the steam pipeline is equipped with a three-way valve or a distributor. The first outlet of the three-way valve or the distributor is connected to the first condenser, and the second outlet is connected to the second condenser. The control unit is electrically connected to the three-way valve or the distributor and is used to control the steam distribution ratio.

3. The dual-condenser adaptive loop heat pipe cooling system according to claim 1, characterized in that, The steam pipeline includes a main steam pipe, a first branch pipe and a second branch pipe. The first branch pipe is connected to the first condenser and the second branch pipe is connected to the second condenser. The first branch pipe and / or the second branch pipe are equipped with a one-way valve or a heat-driven valve driven by steam pressure to achieve passive distribution of steam flow.

4. The dual-condenser adaptive loop heat pipe cooling system according to claim 1, characterized in that, The control unit is configured as follows: When the battery pack temperature is lower than the first preset temperature threshold, control steam to enter only the first condenser; When the battery pack temperature is higher than the first preset temperature threshold and the water temperature is lower than the second preset temperature threshold, the control steam will only enter the first condenser. When the battery pack temperature is higher than the first preset temperature threshold and the water temperature is higher than the second preset temperature threshold, steam is controlled to enter the first condenser and the second condenser simultaneously. When the water temperature is higher than the second preset temperature threshold and the ambient temperature is lower than the third preset temperature threshold, the steam distribution ratio of the second condenser is increased.

5. The dual-condenser adaptive loop heat pipe cooling system according to claim 1, characterized in that, The second condenser is a finned tube air-cooled heat exchanger. The second condenser is installed on the upper part of the photovoltaic support column on the water surface or on the back of the photovoltaic module, and heat dissipation is achieved by natural convection or forced airflow on the back of the photovoltaic module. The installation height of the second condenser is not lower than the installation height of the evaporator, so that the condensate in the second condenser can flow back to the evaporator by gravity.

6. The dual-condenser adaptive loop heat pipe cooling system according to claim 1, characterized in that, The liquid outlets of the first and second condensers are connected to the liquid pipeline through a manifold, and a one-way valve is installed in the manifold to prevent backflow of condensate.

7. The dual-condenser adaptive loop heat pipe cooling system according to claim 1, characterized in that, A phase change material layer is also provided between the evaporator and the energy storage battery pack to absorb instantaneous heat spikes.

8. The dual-condenser adaptive loop heat pipe cooling system according to claim 1, characterized in that, The system is equipped with multiple evaporators, the steam outlets of the multiple evaporators are connected in parallel to the steam pipeline, the liquid inlets of the multiple evaporators are connected in parallel to the liquid pipeline, and they share the first condenser and the second condenser.

9. A heat dissipation control method, characterized in that, The dual-condenser adaptive loop heat pipe cooling system according to any one of claims 1 to 8 comprises: Real-time acquisition of battery pack temperature Tb, water temperature Tw, and ambient temperature Ta; When Tb≤T1, control steam only enters the first condenser, and the system operates in underwater single condenser mode. When Tb>T1 and Tw≤T2, control the steam to enter only the first condenser; When Tb>T1 and Tw>T2, control steam enters the first condenser and the second condenser simultaneously, and the system operates in dual-condenser cooperative mode. Wherein, T1 is the first preset temperature threshold and T2 is the second preset temperature threshold.

10. A floating energy storage system, characterized in that, It includes a water-surface photovoltaic module, a photovoltaic support column, an energy storage battery pack, and a dual-condenser adaptive loop heat pipe cooling system as described in any one of claims 1 to 8.

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