Gigwatt-level electrode heating device and method for heating high-capacity heat storage water body

Abstract

The invention provides a gigawatt-level electrode heating device and method for heating a high-capacity heat storage water body, and the device comprises three metal electrode cylinders which are correspondingly connected with A, B and C phases of a three-phase alternating current respectively, and are used for receiving external circulating water; the three metal center cylinders are arranged corresponding to the three metal electrode cylinders respectively, the outer wall of each metal center cylinder is coated with an insulating coating, and the metal center cylinders are connected to the corresponding phases of the three-phase alternating current respectively; and the upper-section electrode group is connected between the metal central cylinder and the metal electrode cylinder, consists of a plurality of upper-section electrode tubes and a flanged polytetrafluoroethylene electrode connecting assembly, and is used for realizing insulation isolation and water flow on-off control between the metal central cylinder and the metal electrode cylinder. The problems that in a super-large-scale water body heat storage system in the fields of regional heating, centralized heating in large industrial parks, cross-seasonal heat storage and the like, electric heating power above the gigawatt level is generally needed, and as many as hundreds of devices are needed to be connected in parallel in conventional electric heating devices, the system is complex, cost is high, and the requirements cannot be met are solved.

Description

Technical Field

[0001] This invention relates to the field of electric heating and thermal energy storage technology, and more specifically, to a gigawatt-level electrode heating device and method for heating large-capacity hot water storage bodies. Background Technology

[0002] Against the backdrop of global efforts to address climate change and energy transition, the installed capacity of renewable energy sources, represented by wind and solar power, has grown rapidly. As of June 2025, my country's combined installed capacity of wind and solar power exceeded 1.6 billion kilowatts, making it the largest power source. However, the inherent intermittency, volatility, and anti-peak-shaving characteristics of renewable energy pose a severe challenge to the real-time balance and stable operation of the power system. Traditional thermal power units have limited adjustment flexibility and cannot fully adapt to the drastic load fluctuations caused by the high proportion of renewable energy integrated into the grid. Therefore, developing large-scale, long-term, and low-cost energy storage technologies is crucial for achieving efficient renewable energy absorption and enhancing the resilience of the power system.

[0003] In final energy consumption, thermal energy accounts for over 50%, making thermal energy storage a highly promising area for large-scale energy storage. Among these, sensible thermal energy storage technology, using water as the storage medium, has attracted widespread attention due to its significant advantages, including high energy density, extremely low medium cost, system simplicity, long lifespan, environmental friendliness, and the ability to simultaneously meet short-term (daily / weekly) peak-shaving and long-term (cross-seasonal) energy storage needs. In particular, the unit energy cost of thermal energy storage can be reduced to one-tenth or even less of the cost of electricity storage, demonstrating a significant economic advantage.

[0004] Currently, large-scale thermal storage systems using water as the medium primarily rely on electric heating technology. The mainstream equipment on the market are electric heating tube boilers and electrode boilers. Electric heating tube boilers heat metal resistance wires with electric current, and then transfer the heat to the water through insulation and the tube wall. Their single-unit power is typically small, generally not exceeding 5 MW. Electrode boilers, on the other hand, utilize the conductivity of water, allowing current to flow directly through the water being heated, achieving a direct and efficient conversion of electrical energy into thermal energy. Their single-unit power can reach 30-50MW, and they are more commonly used in small and medium-scale thermal storage projects.

[0005] However, for ultra-large-scale applications such as regional heating, centralized energy supply for large industrial parks, and cross-seasonal thermal storage at the megawatt-hour or even gigawatt-hour level, the required instantaneous heating power often reaches hundreds of megawatts or even gigawatts. If existing electrode boiler technology is used, dozens or even hundreds of devices need to be complexly integrated in parallel. This not only results in a huge system footprint, extremely complex piping, valves, and control systems, and high initial investment and maintenance costs, but also introduces more points of failure, reducing the overall reliability and safety of the system, severely hindering the large-scale commercial promotion of large-capacity water thermal storage technology. Therefore, we have made improvements and proposed a gigawatt-level electrode heating device and method for heating large-capacity water storage bodies. Summary of the Invention

[0006] The purpose of this invention is to overcome the technical bottleneck that existing electrode boilers have limited single-unit power and cannot directly meet the gigawatt-level heating requirements of ultra-large-scale thermal storage systems.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A gigawatt-level electrode heating device and method for heating large-capacity hot water storage bodies, in order to improve the above-mentioned problems.

[0008] The application is as follows: A gigawatt-level electrode heating device for heating large-capacity hot water storage bodies includes: Three metal electrode cylinders are connected to phases A, B, and C of a three-phase AC power supply, respectively, to receive external circulating water. Three metal center cylinders are respectively set up corresponding to three metal electrode cylinders. The outer wall of each metal electrode cylinder is coated with an insulating coating and is respectively connected to the corresponding phase of the three-phase alternating current. The upper electrode group, connected between the metal central cylinder and the metal electrode cylinder, consists of multiple upper electrode tubes and flanged PTFE electrode connection components, and is used to achieve insulation isolation and water flow interruption control between the metal central cylinder and the metal electrode cylinder. The lower electrode group, located at the bottom of the metal electrode cylinder, consists of multiple lower electrode tubes and is used for secondary heating of the water flow. The receiving device is located below the lower electrode group and is used to collect the heated water flow and return it to the hot water storage body. The metal central cylinder operates with full liquid, while the metal electrode cylinder operates without full liquid. A float device is installed in the upper electrode tube to control the flow of water by setting a pressure.

[0009] As a preferred technical solution of this application, each upper electrode tube in the upper electrode group is equipped with a float device, which is used to automatically open the water flow channel when the set pressure is reached.

[0010] As a preferred technical solution of this application, a rectifier is provided at the connection between the lower electrode tube and the metal electrode cylinder in the lower electrode group to improve the flow field distribution of the falling water.

[0011] As a preferred technical solution of this application, both the metal center cylinder and the metal electrode cylinder are large-sized cylindrical structures, which are suitable for connection to large water storage containers as components of a heating system.

[0012] As the preferred technical solution of this application, the overall power of the device can reach the gigawatt level, and it is suitable for district heating, industrial park heating, cross-seasonal heat storage or new energy consumption scenarios.

[0013] A gigawatt-level electrode heating method for heating large-capacity hot water storage bodies includes the following steps: pumping water from the hot water storage body to three metal central cylinders via an external circulation pump; When the pressure inside the metal center cylinder reaches the set value, the float device in the upper electrode tube is activated, and the water flows down into the metal electrode cylinder. The water flows through the metal electrode cylinder and is connected to the electrodes, thus achieving the first heating. The water continues to fall and undergoes a second heating process via the lower electrode group. The heated water is collected by a receiving device and returned to the hot water storage body, forming a closed loop.

[0014] As a preferred technical solution of this application, the residence time of water in the metal central cylinder and the metal electrode cylinder and the heating power can be controlled by adjusting the flow rate of the circulating pump and the electrode voltage.

[0015] As a preferred technical solution of this application, the method is applicable to large-scale thermal energy storage and release in lakes, ponds or artificial hot water bodies.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: In the scheme of this application: 1. By using the external giant water body as an extension of the "boiler drum", this device completely breaks free from the constraints of traditional pressure vessels in terms of size, wall thickness and manufacturing cost, making it possible to design and build electrode heaters with a single unit power of hundreds of megawatts to gigawatts, thus meeting the demand of ultra-large-scale thermal storage for centralized high-power heat sources. 2. Compared with the scheme of using dozens of traditional electrode boilers in parallel, the present invention can achieve the required total power with a single unit, eliminating a large number of independent boiler drums, shells, body valves and decentralized control systems, which significantly reduces the complexity of pipeline connection, infrastructure construction, electrical access and control system, thereby greatly reducing one-time investment and long-term operation and maintenance costs. 3. This invention abandons the traditional electrode boiler structure and uses large water storage containers such as pools and lakes as boiler drums by setting up a graded metal central cylinder and metal electrode cylinders, thus innovating the electrode group heating method to meet the GW-level heating power requirements. 4. The upper metal central cylinder adopts a closed design, and the opening and closing are controlled by setting the pressure through a float device to precisely control the water flow; 5. Electrode groups are set at both the upper and lower parts of the metal electrode cylinder, which can achieve two heating cycles in one cycle, reducing operating energy consumption. Attached Figure Description

[0017] Figure 1 A single-phase side view of the connection structure between the upper electrode group and the metal central cylinder of the gigawatt-level electrode heating device and method for heating large-capacity hot water storage provided in this application. Figure 2 A front view of the gigawatt-level electrode heating device and method for heating large-capacity hot water storage bodies provided in this application; Figure 3 A partial schematic diagram of the connection structure between the lower electrode group and the receiving device for the gigawatt-level electrode heating device and method for heating large-capacity hot water storage provided in this application.

[0018] The image shows: 1. Metal center cylinder; 3. Metal electrode cylinder; 6. Upper electrode tube; 7. Flanged PTFE electrode connection assembly; 8. Float device; 10. Lower electrode tube; 11. Rectifier; 12. Receiving device. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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.

[0020] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate some embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments, features, and technical solutions in the embodiments of the present invention can be combined with each other.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] like Figures 1-3As shown, this embodiment proposes a gigawatt-level electrode heating device for heating large-capacity hot water storage bodies, comprising: Three metal electrode cylinders 3 are respectively connected to phases A, B, and C of the three-phase AC power supply and are used to receive external circulating water; Three metal center cylinders 1 are respectively set with three metal electrode cylinders 3. The outer wall of each metal center cylinder 1 is coated with an insulating coating and is respectively connected to the corresponding phase of the three-phase alternating current. The upper electrode group is connected between the metal center cylinder 1 and the metal electrode cylinder 3. It consists of multiple upper electrode tubes 6 and a flanged PTFE electrode connection assembly 7, and is used to achieve insulation isolation and water flow interruption control between the metal center cylinder 1 and the metal electrode cylinder 3. The lower electrode group, located at the lower part of the metal electrode cylinder 3, consists of multiple lower electrode tubes 10 and is used for secondary heating of the water flow. The receiving device 12 is located below the lower electrode group and is used to collect the heated water flow and return it to the hot water storage body. The metal central cylinder 1 operates with full liquid, while the metal electrode cylinder 3 operates without full liquid. The upper electrode tube 6 is equipped with a float device 8, which controls the flow of water by setting a pressure.

[0023] The core of this device lies in abandoning the traditional design paradigm of treating the "boiler drum" as an independent pressure vessel in electrode boilers, and innovatively treating large external hot water storage bodies (such as artificial lakes, underground pools, and large storage tanks) as a "giant boiler drum" or an extension of the system. This device, serving as the high-power "heating core" of the "giant boiler drum," is inserted into and connected to it, thereby physically breaking through the volume and pressure limitations of traditional boiler drums and providing a fundamental possibility for designing gigawatt-level single-unit power.

[0024] Specifically, the three-phase metal central cylinder 1 assembly consists of three independent large-sized metal cylinders, corresponding to phases A, B, and C of the three-phase AC power supply, respectively. The metal central cylinder 1 serves as the water inlet distribution and primary heating chamber of the heating system. It has a water inlet at its top, connected to the hot water storage body to be heated via an external high-flow circulation pump. During operation, all three metal central cylinders 1 remain fully filled with liquid, meaning the liquid level is always maintained near the top, ensuring a stable water flow path and electrical connection.

[0025] Specifically, the three-phase metal electrode cylinder 3 assembly consists of three large-sized metal cylinders, spatially positioned below the three central metal cylinders 1. One end of each of the three metal electrode cylinders 3 is directly electrically connected to phases A, B, and C of the three-phase AC power supply, serving as the three high-voltage electrodes of the system. Its outer wall is entirely coated with a high-performance insulating coating (such as a special ceramic coating or a polytetrafluoroethylene composite coating) to ensure electrical isolation from surrounding water bodies and grounding components. During operation, the metal electrode cylinders 3 are not fully filled with liquid; the liquid level is typically maintained at the middle of its height, providing space for water to fall and for gas-liquid separation.

[0026] Each upper electrode tube 6 in the upper electrode group is equipped with a float device 8, which is used to automatically open the water flow channel when the set pressure is reached. The upper electrode group connects the metal center cylinder 1 and the metal electrode cylinder 3, enabling hydraulic connection, electrical insulation, and flow control between them. The upper electrode group consists of multiple (e.g., 20, 30, or more) independent upper electrode tubes 6. The upper end of each upper electrode tube 6 is connected to the bottom of the metal center cylinder 1 via a flanged PTFE electrode connection assembly 7, and the lower end is connected to the upper part of the metal electrode cylinder 3. This connection assembly not only provides mechanical connection and sealing, but its PTFE material also ensures reliable electrical insulation between the metal center cylinder 1 (at high potential or grounded, depending on the system grounding design) and the metal electrode cylinder 3 (directly energized). Specifically, a float device 8 is integrated inside or at the inlet of each upper electrode tube 6. This device is essentially a hydraulically or pressure-controlled one-way valve. When the water pressure inside the metal central cylinder 1 is lower than a set threshold, the float closes the flow channel under the action of gravity or a spring; when the water pressure inside the metal central cylinder 1 rises to the set threshold due to water supply from the circulating pump, the water flow pressure drives the float to open, allowing water to flow down through the upper electrode tube 6 into the metal electrode cylinder 3. By setting different opening pressures, the timing and flow distribution of the water entering the heating stage can be precisely controlled.

[0027] A rectifier 11 is provided at the connection between the lower electrode tube 10 and the metal electrode cylinder 3 in the lower electrode group to improve the flow field distribution of the falling water.

[0028] The lower electrode group is located at the bottom of each metal electrode cylinder 3 and is used for secondary enhanced heating of the water flow. The lower electrode group is also composed of multiple independent lower electrode tubes 10. The upper ends of these lower electrode tubes 10 are connected to the bottom or lower side of the metal electrode cylinder 3, and the lower ends converge or directly lead to the receiving device 12. A rectifier 11 is provided at the connection inlet of each lower electrode tube 10 and the metal electrode cylinder 3. This device can be a guide vane, a flow equalization orifice plate, a cyclone separator, or other structural forms. Its main function is to improve the flow field of water falling from the metal electrode cylinder 3, so that it enters the lower electrode tube 10 more uniformly and smoothly, avoid water segregation, eddies, or air blockage, and ensure the uniformity and stability of secondary heating.

[0029] The lower electrode group is located at the bottom of each metal electrode cylinder 3 and is used for secondary enhanced heating of the water flow. The lower electrode group also consists of multiple independent lower electrode tubes 10. The upper ends of these lower electrode tubes 10 are connected to the bottom or lower side of the metal electrode cylinder 3, and the lower ends converge or directly lead to the receiving device 12.

[0030] The receiving device 12 is used to collect all the high-temperature water flow after being heated twice. The receiving device 12 is typically one or more collecting hoppers, collecting chambers or pipes, whose outlets are ultimately led back to the external hot water storage body through insulated pipes, thus forming a complete closed or semi-closed circulation loop.

[0031] Both the metal center cylinder 1 and the metal electrode cylinder 3 are large-sized cylindrical structures, suitable for connection to large water storage containers as components of a heating system.

[0032] The overall power of the device can reach gigawatt level, and it is suitable for district heating, industrial park heating, cross-seasonal heat storage or new energy consumption scenarios.

[0033] The device is equipped with a supporting and insulating structure. It is fixed in the water or in a special equipment compartment by a high-strength insulating support or frame to ensure that there is a sufficient safe electrical distance and mechanical stability between each live part (metal electrode cylinder 3) and the grounding part (metal center cylinder 1, receiving device 12, external water container, etc.).

[0034] A gigawatt-level electrode heating method for heating large-capacity hot water storage bodies includes the following steps: water from the hot water storage body is pumped to three metal central cylinders 1 via an external circulation pump; when the pressure inside the metal central cylinder 1 reaches a set value, the float device 8 in the upper electrode tube 6 is activated, and the water flows down to the metal electrode cylinder 3; the water flows into the metal electrode cylinder 3 and is connected to the electrodes, achieving the first heating; the water continues to fall and undergoes a second heating through the lower electrode group; the heated water is collected by the receiving device 12 and returned to the hot water storage body, forming a closed loop.

[0035] The external circulation pump is started to pump the low-temperature (or room-temperature) water in the hot water storage body to be heated to the three metal central cylinders 1, filling them and maintaining them in a full liquid state, and the pressure gradually increases; when the water pressure in a certain metal central cylinder 1 rises to the set opening pressure of the float device 8 in the corresponding upper electrode group, the float device 8 opens, and the water flows down into the corresponding metal electrode cylinder 3 through the corresponding upper electrode tube 6; during the process of the water flow entering the metal electrode cylinder 3 and when it falls inside the metal electrode cylinder 3, it comes into contact with the inner wall of the charged metal electrode cylinder 3, and the current directly forms a circuit from the wall of the metal electrode cylinder 3 through the water body. Due to the resistance of water, electrical energy is directly converted into heat energy, providing the first concentrated heating of the water flow. The water, after its first heating, continues to fall to the bottom of the metal electrode cylinder 3 and is evenly distributed by the rectifier 11 located on it, entering multiple lower electrode tubes 10. As the water flows through the lower electrode tubes 10, the lower electrode tubes 10 themselves act as extension electrodes or form a new current path with the receiving device 12, allowing current to flow through the water again, achieving a second enhanced heating. All the high-temperature water flows after the two heating processes converge in the receiving device 12 and are transported back to the external hot water storage body (such as a lake or pool) through the outlet pipe, completing one heating cycle. Through continuous operation, the overall temperature of the hot water storage body is raised. By adjusting the speed of the external circulation pump (controlling the total flow rate) and / or adjusting the voltage input to the three-phase metal electrode cylinder 3 (controlling the current density and heating power), the total heating power and outlet water temperature of the system can be continuously and precisely controlled.

[0036] The residence time of water in the metal central cylinder 1 and the metal electrode cylinder 3, as well as the heating power, can be controlled by adjusting the flow rate of the circulating pump and the electrode voltage.

[0037] The method is applicable to large-scale thermal energy storage and release in lakes, ponds, or artificial hot water bodies.

[0038] like Figure 1 As shown, in a preferred embodiment, based on the above method, the device further includes three metal central cylinders 1 (corresponding to phases A, B, and C), with a cylinder diameter of 2 meters and a height of 15 meters, operating with full liquid; a metal electrode cylinder 3 is correspondingly installed below each metal central cylinder 1, coated with a ceramic insulating coating, operating without full liquid; the upper electrode group consists of 20 upper electrode tubes 6, each tube equipped with a float valve, with an opening pressure set at 0.3 MPa. The lower electrode group also consists of 20 lower electrode tubes 10, with a spiral guide vane at the inlet serving as a rectifier 11; the receiving device 12 is a conical water collecting hopper, with the bottom connected to a return pipe to the hot water storage body.

[0039] During operation, the circulating pump pumps lake water at a rate of 5000m... 3A flow rate of [flow rate] / h is pumped into the metal central cylinder 1. When the pressure reaches 0.3 MPa, the float valve opens, and the water flows through the upper electrode group down to the metal electrode cylinder 3, where it conducts electricity with the electrodes to complete the first heating (approximately 30°C increase). The water then flows through the lower electrode group for a second heating (an additional 20°C increase), and finally flows back into the lake via the receiving device 12, forming a closed loop. The total heating power of the system can reach 1000 MW.

[0040] In one embodiment, the device is used for regional cross-seasonal thermal storage lakes, specifically for a cross-seasonal thermal storage artificial lake used for regional heating of tens of millions of square meters, with an effective water storage volume of approximately 5 million cubic meters.

[0041] The internal structure of the device includes: ① Metal Central Cylinder 1: Made of Q345R pressure vessel steel plate, each cylinder has a diameter of 2.5 meters, a height of 20 meters, and a wall thickness of 30 millimeters. A water inlet is located at the top of the cylinder, and the bottom is connected to the upper electrode group via a flange. The three metal central cylinders 1 are arranged in an equilateral triangle with a center-to-center distance of 5 meters. The design working pressure is 0.8 MPa. ② Metal electrode cylinder 3: Made of 316L stainless steel, each cylinder has a diameter of 2.2 meters, a height of 18 meters, and a wall thickness of 25 mm. The outer wall is coated with a 0.5 mm thick alumina ceramic insulating coating with a withstand voltage greater than 30 kV / mm. The top of the cylinder is connected to the upper electrode group through an insulating component. A high-voltage bushing is provided on the upper side, leading out the high-voltage electrode terminal and connecting to a 35 kV three-phase AC power supply. ③ Upper electrode group: Composed of 30 upper electrode tubes 6, evenly distributed at the bottom of the metal central cylinder 1. Each electrode tube is an insulating ceramic tube or a metal tube with an inner diameter of 80 mm. The float device 8 is integrated inside the tube, using a high-temperature resistant engineering plastic float and spring structure, with an opening pressure set at 0.5 MPa; ④ Lower section electrode group: It consists of 30 lower section electrode tubes 10, which are evenly distributed at the bottom of the metal electrode cylinder 3. Each electrode tube is a 316L stainless steel tube with an inner diameter of 100 mm. The flow rectifier 11 at the inlet is a three-piece spiral guide vane, which makes the water flow generate a gentle swirling flow and promotes uniform mixing. ⑤ Receiving device 12: A conical stainless steel collecting hopper, 6 meters in diameter at the top, connected at the bottom to a high-temperature water outlet pipe (1.2 meters in diameter). The outlet pipe is insulated and extends to another area of ​​the lake to prevent short-circuiting of hot and cold water; ⑥ Support: The entire device is supported by a giant truss made of composite insulation material and sits on a pre-cast concrete foundation on the lakebed.

[0042] During the thermal storage season (such as summer), the external circulation pump (total power approximately 15 MW, flow rate 40,000 m³ / h) is started. 3 / h), pumping the low-temperature water of about 15℃ in the lake into three metal central cylinders 1; When the pressure inside the metal central cylinder 1 reaches 0.5 MPa, the float devices 8 of each upper section electrode tube 6 are opened one after another, and the water flows through the upper section electrode tube 6 at an average flow velocity of about 2 m / s, forming multiple stable jets that enter the metal electrode cylinder 3. As the water flows down inside the metal electrode cylinder 3, it comes into contact with the inner wall of the metal electrode cylinder 3, which carries a voltage of 35 kV. Since the lake water has been pretreated and its conductivity is controlled at around 500 μS / cm, a strong current (the steady-state current per phase can reach several thousand amperes) passes directly through the water flow, generating huge Joule heat and completing the first heating. This stage can instantly raise the water temperature by about 25-30℃.

[0043] After being heated to about 45°C, the water continues to fall and enters the lower electrode tube 10 through the rectifier 11. A potential difference is formed between the lower end of the lower electrode tube 10 and the grounded receiving device 12. The current flows through the falling water column again for a second heating, and the water temperature rises by about 15-20°C. Finally, the high-temperature water at about 60-65℃ is collected in the receiving device 12 and transported to the designated area of ​​the lake for storage through the large-diameter outlet pipe at a flow rate of about 1 m / s. The entire system operates continuously in a closed-loop manner. By adjusting the frequency converter of the circulating pump, the total flow rate can be adjusted to 20,000-50,000 m³ / h. 3 The input voltage can be adjusted within the range of / h; through the voltage regulating transformer on the grid side, the input voltage can be adjusted within the range of 25-38 kV, thereby achieving continuous and stable adjustment of the total heating power of the system between 500MW and 1200 MW.

[0044] A single unit of this device can raise the temperature of 5 million cubic meters of water by approximately 40°C within a quarter, storing over 2.3 × 10⁻⁶ heat. ^14 The power generation capacity of 640 joules (approximately 640 GWh) meets the heating needs of tens of millions of square meters of buildings for one month under extreme winter weather conditions, and has successfully absorbed a large amount of excess wind and solar power during the summer.

[0045] In another embodiment, the device is used to replace molten salt thermal storage in solar thermal power generation. Specifically, the device is applied to a tower solar thermal power plant, where water thermal storage is intended to replace the high-cost molten salt thermal storage, and a series of large steel hot water storage tanks are constructed as thermal storage units.

[0046] The internal structure of the specific device is consistent with that of Embodiment 1, except that the dimensions of several structures are slightly different from those in Embodiment 1. Specifically, the metal central cylinder 1 has a diameter of 1.5 meters and a height of 15 meters; the metal electrode cylinder 3 has a diameter of 1.3 meters and a height of 12 meters; the upper and lower electrode groups each use 20 electrode tubes; the entire device is designed as a modular standard unit, with a single module designed for a power of 250MW; one set of this modular heating device is vertically inserted into the center of each large hot water storage tank (50 meters in diameter and 20 meters in height), and a 1GWh thermal storage project requires 4 storage tanks and 4 sets of heating modules.

[0047] During periods of abundant solar energy, solar collectors are used for heating. At night or on cloudy days, electrode heating modules are activated to generate electricity from grid power or the power plant's own gas turbine for heating or to maintain the thermal storage temperature. The modular design facilitates installation, maintenance, and power combination.

[0048] Furthermore, an online water quality monitoring and conductivity fine-tuning system has been added to the device to ensure heating efficiency and electrical safety. Simultaneously, it is deeply integrated with the power plant's DCS system to achieve optimal coordinated operation with the solar collector field.

[0049] In this device, the float device 8 can specifically be a Danfoss EV220B series stainless steel float valve, or a mechanical level control valve with equivalent function. This model has a 304 stainless steel body and a hollow stainless steel float, with the valve core opening and closing achieved through a lever-based mechanical structure. Its nominal diameter can be selected as DN50 (corresponding to an electrode tube with an inner diameter of approximately 50mm), the working pressure range is 0.1-1.0 MPa, and the working temperature can reach 150°C, fully meeting the requirements of the 0.5 MPa set opening pressure and high-temperature water environment in Example 1. The core function of this valve is to mechanically cut off or connect the flow channel by responding to changes in liquid level or pressure through the displacement of the float. Furthermore, those skilled in the art can select other devices with the same or similar pressure / level sensing and flow channel on / off control functions based on the actual required opening pressure accuracy, flow rate, and media characteristics. For example: electromagnetic pilot-operated pressure control valves, such as the Bernard PH-7 series, use pressure sensor signals to control the electromagnetic coil to drive the valve core, enabling higher precision pressure setting and remote electrical control; self-operated pressure regulating valves (with pilot valves): utilize the pressure of the medium itself to control the opening and closing of the main valve through the pilot valve, suitable for high flow rate applications; and so on.

[0050] In this device, the core of the flanged PTFE electrode connection assembly 7 lies in providing an interface that combines reliable sealing, high-strength mechanical connection, and excellent electrical insulation performance. In this application and the above embodiments, a molded reinforced PTFE flange kit can be used. Specifically, the assembly includes a steel flange (such as the WN-RF flange in HG / T 20592 standard) welded to the bottom of the metal central cylinder 1, a PTFE insulating bushing with a flange, and a set of high-strength insulating bolts (such as glass fiber reinforced nylon bolts M16×100) and nuts. The PTFE bushing is molded in one piece, and the flanged part is tightly pressed between the metal flange faces to ensure a seal; the bushing body passes through the connection, completely separating the metal parts of the metal central cylinder 1 and the metal electrode cylinder 3. Its breakdown voltage strength should be ≥30 kV / mm, and its long-term temperature resistance should be ≥150°C. In addition, those skilled in the art can use other components as needed, as long as they can achieve the same insulation and connection functions, such as: integral ceramic insulator components: insulators with flange structures made of high-purity alumina ceramics, which are brazed to metal flanges through metallized end faces; connectors cast from composite insulating materials (such as epoxy quartz sand): metal connectors and liquid epoxy resin composites are cast into a mold in one step to form a robust insulator; other high-performance engineering plastics: such as flange connectors made of polyetheretherketone (PEEK), etc.

[0051] In this device, to ensure safety, the outer wall of the metal electrode cylinder 3 needs to be coated with a continuous, dense, and highly adhesive insulating coating. In this application and the above embodiments, an alumina (Al2O3) ceramic coating can be prepared using atmospheric plasma spraying (APS) technology. Specific process parameters include: using high-purity α-Al2O3 powder (-100 mesh / +10μm) as raw material, melting it with plasma jet, and then spraying it at high speed onto the outer surface of a 316L stainless steel cylinder that has undergone sandblasting and roughening. The coating thickness is controlled between 0.3-0.8 mm, and after sealing, its volume resistivity is >10 Ω·cm. 12 With a strength of Ω·cm, a withstand voltage of >30 kV / mm, and a thermal conductivity of approximately 3 W / (m·K), this coating provides both insulation and facilitates some heat dissipation. The coating requires 100% spark leak testing to ensure there are no penetrating defects. In addition, other coatings or coverings that provide long-term reliable insulation protection can be used on top of the above. These include: high-temperature curing insulating varnishes, such as silicone-modified epoxy resin insulating varnishes, which are applied in multiple coats and cured at high temperatures to form a thick insulating layer; integral insulating sleeves, using radiation-crosslinked polyolefin heat-shrink tubing or prefabricated silicone rubber insulating tubing, which are heated and shrunk or assembled and secured to the outside of the metal electrode cylinder 3; composite insulation systems, which involve first spraying an aluminum-silicate bonding underlayer, then spraying an alumina ceramic working layer, and finally impregnating with a layer of silicone varnish for sealing, etc.

[0052] In this device, the rectifier 11 is used to optimize fluid distribution and eliminate or reduce the eddies, flow deviations, or gas-liquid two-phase flow instability that may occur when a large flow rate falls. In this application and the above embodiments, it can be designed as a three-piece guide plate fixed in the inlet of the lower electrode tube 10. The guide plate is made of 316L stainless steel with a thickness of 3mm. Three pieces are uniformly welded along the circumference of the tube wall. Each guide plate is at a 20-30 degree angle to the pipe axis and is slightly bent towards the center of the tube. This structure can produce a gentle swirling effect on the falling water flow, promote the uniform distribution of water flow along the tube wall, and break up large air bubbles. In addition, those skilled in the art can adopt other structures that can achieve flow field rectification according to actual needs, such as: porous flow equalizer: a steel plate with multiple small holes (opening ratio of 50%-70%) is installed at the inlet to achieve flow equalization through throttling and dispersion; hydrocyclone: ​​designed with fixed spiral blades to generate forced swirling flow of water, and centrifugal force makes the fluid more uniform; tapered tube or venturi tube structure: stabilizes and accelerates the fluid by changing the flow cross-sectional area, etc.

[0053] In this device, the giant system described in Embodiment 1 requires an external circulation pump with extremely high flow rate and high head. In this application and the above embodiments, a single-stage, double-suction, split-case centrifugal pump is used, such as a large model from the KSB RPH series or Grundfos NB series; specifically, one or more pumps can be connected in parallel. Example parameters for a single pump: flow rate Q = 20000 m³ / h, head H = 60 m, power P ~ 4500 kW, voltage 10 kV; the pump casing and impeller materials must be suitable for the water composition (possibly containing trace minerals), and duplex stainless steel can be selected to balance strength, corrosion resistance, and cavitation resistance; a high-voltage variable frequency motor is used for drive to achieve precise flow rate regulation; furthermore, other materials can be used as needed for replacement.

[0054] In this device, the supporting insulating pillars used to support and fix the entire device and ensure electrical insulation can be, in this application and the above embodiments, high-temperature impregnated epoxy resin glass fiber wound tubes (commonly known as epoxy tubes), for example, with a diameter of Φ300mm, a wall thickness of 30mm, and a length determined according to the support height. These tubes have high mechanical strength (bending strength > 300 MPa) and excellent insulation performance (volume resistivity > 10). 13 It has a strength of Ω·cm, is water-resistant and weather-resistant, and is equipped with pre-embedded metal flanges at both ends. It is connected to the equipment foundation and the main body of the device by bolts. In addition, other materials can be used for replacement as needed.

[0055] In use, this application employs the following: Three large-sized metal cylinders 1 are installed as central cylinders corresponding to the A, B, and C phases of a three-phase AC power supply. Each of the three central metal cylinders 1 is connected to a high-flow-rate circulating water supply, operating at full liquid level. Three metal electrode cylinders 3 are installed below the three central metal cylinders 1. These three electrode cylinders 3 operate partially submerged, with an insulating coating on their outer walls. One end of each of the three electrode cylinders 3 is connected to one of the A, B, or C phases of the three-phase AC power supply. The upper part of the electrode cylinders 3 is connected to the three central metal cylinders 1 via an upper electrode group. This upper electrode group consists of multiple (20 shown in the diagram) independent upper electrode tubes 6 and flanged PTFE electrode connection assemblies 7, providing insulation between the central metal cylinders 1 and the electrode cylinders 3. Each upper electrode tube 6 contains a float device 8, with a set pressure used to control opening and closing. The lower part of the metal electrode cylinder 3 is provided with a lower section electrode group, which is composed of multiple independent lower section electrode tubes. A receiving device 12 is provided below the lower section electrode group. A rectifier 11 is provided at the connection between the lower section electrode tube 10 in the lower section electrode group and the metal electrode cylinder 3 to improve the flow field. When heating is required, water from a large volume of water is pumped to the metal central cylinder 1 via an external circulation pump. Once the set pressure is reached, a float device 8 inside the upper electrode group opens the pipe, allowing water to flow downwards. The water flowing into the metal central cylinder 1 generates heat after being energized by the current flowing through the electrode cylinders, completing the first heating stage. The water then enters the metal electrode cylinder 3, flows through the lower electrode group, and enters the receiving device 12 for convergence. After being energized again, it generates heat, completing the second heating stage. Finally, the water is diverted to lakes or other bodies of water, forming a closed-loop circulation.

[0056] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described herein. Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to the specific embodiments described above. Therefore, any modifications or equivalent substitutions to the present invention, as well as all technical solutions and improvements that do not depart from the spirit and scope of the invention, are covered within the scope of the claims of the present invention.

Claims

1. A gigawatt-level electrode heating device for heating large-capacity hot water storage bodies, characterized in that, include: Three metal electrode cylinders (3) are respectively connected to the A, B and C phases of the three-phase AC power supply and are used to receive external circulating water; Three metal center cylinders (1) are respectively set with three metal center cylinders (1), and the outer wall of each metal electrode cylinder is coated with an insulating coating and is respectively connected to the corresponding phase of the three-phase AC power; The upper electrode group is connected between the metal central cylinder (1) and the metal electrode cylinder (3). It consists of multiple upper electrode tubes (6) and a flanged PTFE electrode connection assembly (7). It is used to achieve insulation isolation and water flow interruption control between the metal central cylinder (1) and the metal electrode cylinder (3). The lower electrode group is located at the lower part of the metal electrode cylinder (3) and consists of multiple lower electrode tubes (10) for secondary heating of the water flow. The receiving device (12) is located below the lower electrode group and is used to collect the heated water flow and return it to the hot water storage body. The metal central cylinder (1) operates with full liquid, the metal electrode cylinder (3) operates without full liquid, and the upper electrode tube (6) is equipped with a float device (8) to control the flow of water by setting pressure.

2. The gigawatt-level electrode heating device for heating large-capacity hot water storage bodies according to claim 1, characterized in that, Each upper electrode tube (6) in the upper electrode group is equipped with a float device (8) to automatically open the water flow channel when the set pressure is reached.

3. The gigawatt-level electrode heating device for heating large-capacity hot water storage bodies according to claim 1, characterized in that, A rectifier (11) is provided at the connection between the lower section electrode tube (10) and the metal electrode cylinder (3) in the lower section electrode group to improve the flow field distribution of the falling water.

4. The gigawatt-level electrode heating device for heating large-capacity hot water storage bodies according to claim 1, characterized in that, Both the metal center cylinder (1) and the metal electrode cylinder (3) are large-sized cylindrical structures, suitable for connection to large water storage containers as components of a heating system.

5. The gigawatt-level electrode heating device for heating large-capacity hot water storage bodies according to claim 1, characterized in that, The device has an overall power output of up to gigawatts and is suitable for district heating, industrial park heating, cross-seasonal thermal storage, or new energy consumption scenarios.

6. A gigawatt-level electrode heating method for heating large-capacity hot water storage bodies, characterized in that, The apparatus described in any one of claims 1-5 includes the following steps: pumping water from the hot water storage body to the three metal central cylinders (1) via an external circulation pump. When the pressure inside the metal center cylinder reaches the set value, the float device (8) in the upper electrode tube (6) is activated, and the water flows down to the metal electrode cylinder (3). The water flows through the metal electrode cylinder (3) and is connected to the electrode to achieve the first heating; The water continues to fall and undergoes a second heating process via the lower electrode group. The heated water is collected by the receiving device (12) and returned to the hot water storage body to form a closed loop.

7. The gigawatt-level electrode heating method for heating large-capacity hot water storage bodies according to claim 6, characterized in that, The residence time and heating power of the water in the metal central cylinder (1) and the metal electrode cylinder (3) can be controlled by adjusting the flow rate of the circulating pump and the electrode voltage.

8. The gigawatt-level electrode heating method for heating large-capacity hot water storage bodies according to claim 6, characterized in that, The method is applicable to large-scale thermal energy storage and release in lakes, ponds, or artificial hot water bodies.

Images