Combined electric water heater and control method thereof

Abstract

The application relates to a combined electric water heater and a control method thereof, and relates to the field of electric water heaters. The device adopts a parallel type instant heating and heat storage double-branch water path, a main controller combines a flow sensor and a temperature sensor to control a first heating element and a stop valve; an energy storage box can select a second heating element, a circulating pump and a heat exchange inner container, and is matched with an operator to manually switch working conditions. The control method is divided into manual and automatic modes, the automatic mode switches a single branch and a double branch according to water inflow and water temperature, automatically pre-stores energy when water stops, can forcibly or naturally convect and heat exchange, and adjusts power in real time to stabilize water temperature. The small-water-volume isolation water storage box prevents water scale and saves energy consumption, the large-water-volume double-module increases water heating volume, the structure is simplified to reduce cost, intelligent control considers energy saving and service life of components, and is suitable for water demand of various families.

Description

Technical Field

[0001] This application relates to the field of electric water heater technology, and in particular to a combined electric water heater and its control method. Background Technology

[0002] Currently, most mainstream electric water heaters that combine thermal storage and instant heating adopt a series water circuit layout. Municipal cold water first flows into a large-capacity thermal storage tank for preheating. The preheated water then flows through the instant heating element at the rear for a second heating. The entire system has only a single flow water circuit and no independent branch switching structure. The thermal storage tank is equipped with an independent heating element for thermal storage and insulation. Water temperature and flow rate adjustment are entirely achieved by adjusting the power of the instant heating module at the rear. Long-term use of this structure has revealed multiple unavoidable defects.

[0003] The series-connected water circuit structure amplifies the inherent water quality defects of the hot water storage tank. Long-term storage of stagnant water causes calcium and magnesium ions to continuously precipitate, forming scale that accumulates at the bottom of the tank. During this stagnant process, bacteria and microorganisms proliferate. When using small amounts of water for handwashing or vegetable washing, the water must pass through the storage tank throughout the process, resulting in stagnant water continuously mixing with the outgoing water. Over time, this leads to cloudy and unpleasant-smelling water, severely impacting the hygiene of bathing water. Simultaneously, during low-flow water use, warm water from the storage tank is continuously carried out, requiring repeated heating cycles and generating significant heat loss. The preheated water entering the instant heating module is often too hot, easily triggering overheat protection. This high temperature continuously corrodes the heating element, seals, and temperature sensor, drastically shortening the lifespan of the entire unit's electrical control and heating components.

[0004] The series structure cannot separate the two heating units to work independently. Whether it is a small amount of water used for a short time or a large amount of water used for continuous showering by multiple people, the heat storage tank and the instant heating module must participate in water circulation synchronously. There is no control logic to allocate heating units on demand. In the case of small water usage, the tank continuously stores and dissipates heat, resulting in a large amount of useless energy consumption and low energy utilization. Traditional hot water storage tanks must have an independent heating tube built in to complete heat storage. The two sets of heating elements are used in sync, which increases the cost of material procurement and overall assembly. The synchronous operation of two independent temperature control loops also increases the probability of overall failure. At the same time, the existing equipment only supports a fixed synchronous heating mode and does not have intelligent switching logic that automatically identifies the inlet water temperature and flow rate. Users can only manually adjust the power level, which is difficult to operate and cannot meet the diverse water needs of families. Summary of the Invention

[0005] This application provides a combined electric water heater and its control method to solve the existing technical problems of series-connected combined electric water heaters, such as poor water quality, high energy consumption, easy overheating damage of components, poor flexibility in switching operating conditions, redundant heat storage structure, and simple control logic.

[0006] In a first aspect, this application provides a combined electric water heater, including: a main inlet water line, a main outlet water line, a main controller, a flow sensing component, a temperature sensing component, and parallel-arranged instant heating module branch lines and thermal storage module branch lines, the two branch lines converging and connecting to the main outlet water line; The instant heating module branch is equipped with a first heating element, and the heat storage module branch is equipped with a shut-off valve and an energy storage box. The flow sensing component is mounted on the main inlet water line to collect the inlet water flow signal, and the temperature sensing component is mounted on the main inlet water line and the main outlet water line to collect the inlet water and outlet water temperature signals, respectively. The main controller is electrically connected to the flow sensing component, temperature sensing component, first heating element, and shut-off valve respectively. The main controller receives the signals collected by each sensor and outputs control signals to adjust the working state of the first heating element and the on / off state of the shut-off valve.

[0007] Furthermore, the energy storage box is equipped with a second heating element, which is electrically connected to the main controller and is controlled to start and stop by the main controller.

[0008] Furthermore, the thermal storage module branch is also equipped with a circulation pump, which is electrically connected to the main controller. The circulation pump, shut-off valve, energy storage tank and first heating element can cooperate to form a closed self-circulating hot water storage circuit.

[0009] Furthermore, the energy storage box has a heat exchange structure, with an internal heat exchanger and a medium pipeline for the heat storage medium to enter and exit the storage box cavity.

[0010] Furthermore, it also includes an operator, which is electrically connected to the main controller. The operator is equipped with operation buttons for switching between two water circuit operating conditions: single instant heating module and dual module coordinated operation. The operator sends operating condition switching commands to the main controller.

[0011] Secondly, this application provides a control method for a combined electric water heater, applied to the combined electric water heater described above, including a manual control mode and an automatic control mode. The manual control mode involves the user selecting either a single instant heating module or a dual-module collaborative mode via an operator, with the main controller correspondingly controlling the on / off state of the shut-off valve and the start / stop of the first heating element. The automatic control mode involves the flow sensor and temperature sensor collecting the inlet water flow and temperature in real time, with the main controller calculating and determining whether the cold water can be heated to the target temperature using only the first heating element based on a preset target outlet water temperature. If the target temperature can be met, the shut-off valve is closed, and only the instant heating module branch is used for water supply. If the target temperature cannot be met, the shut-off valve is opened, and both branches are used for water supply simultaneously. When there is no water flow in the entire unit, the main controller opens the shut-off valve, forming a closed-loop water circuit based on the two parallel branches, and starts the first heating element to pre-heat the water inside the energy storage tank.

[0012] Furthermore, when the energy storage box is equipped with a second heating element, the first heating element and the second heating element are activated simultaneously in the dual-module collaborative working state.

[0013] Furthermore, when the thermal storage branch is equipped with a circulating pump, the circulating pump is activated simultaneously during the dual-module water supply and energy storage preheating processes to force water circulation and heat exchange.

[0014] Furthermore, when the thermal storage branch is not equipped with a circulation pump, the control water circuit relies on the temperature difference of the water itself to form a natural convection circulation, thereby achieving uniform heating of the water in the energy storage tank.

[0015] Furthermore, the main controller adjusts the power of the heating element based on the real-time water temperature collected by the outlet water temperature sensor to maintain a stable outlet water temperature.

[0016] The technical solutions provided in this application have the following advantages compared with the prior art: According to the embodiments provided in this application, a parallel dual-branch water circuit layout is adopted. When the water volume is small, the shut-off valve of the heat storage branch is closed, and the water flow does not pass through the energy storage tank at all, which completely avoids the growth of scale and bacteria in the tank and greatly improves the quality of daily water use.

[0017] The heating unit can be started and stopped as needed according to the water load. When the flow rate is low, only the instant heating module is operated to eliminate ineffective heat dissipation and heat replenishment loss of the energy storage tank. When the flow rate is high, the dual modules supply water simultaneously to increase the hot water output, taking into account both energy saving and the need for continuous bathing with large water volume.

[0018] In the instant heating mode, cold water directly enters the first heating element, resulting in a low inlet water temperature. This avoids problems such as high temperature overheating and frequent temperature control protection, reduces the failure rate of heating tubes and sensors due to high temperature corrosion, and extends the service life of all components.

[0019] The second heating element of the energy storage box is an optional accessory. If it is removed, the energy storage is completed by relying on the first heating element in conjunction with a closed self-circulating water circuit. This reduces the need for a heating tube and matching temperature control circuit materials, simplifies the assembly process, and reduces the overall production cost of the machine.

[0020] It comes with both manual and automatic control logic. In automatic mode, no manual adjustment is required. The system automatically matches the water supply branch and heating power, making it easy to operate and suitable for the elderly and children.

[0021] The water inlet and outlet pipe structure of the energy storage tank utilizes the principle of cold water sinking and hot water rising to ensure uniform and stable water temperature. After the water from the two branches is mixed, the water temperature fluctuates little, improving the bathing comfort experience.

[0022] The matching circulation pump can enhance the heat exchange efficiency of the closed water circuit and is compatible with energy storage tanks of different volumes. The model without circulation pump relies on natural convection heating, has a simplified structure, and is suitable for low-cost products for small apartments. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0026] Figure 1 This is a schematic diagram of the module connection of a combined electric water heater provided in an embodiment of this application.

[0027] Figure 2 This is a schematic diagram of water supply for a single instant heating module branch.

[0028] Figure 3 This is a schematic diagram of water usage for the dual-module system.

[0029] Figure 4 This is a schematic diagram of the energy storage box.

[0030] Figure 5 This is a schematic diagram of the module connection using a heat exchange type energy storage box.

[0031] Figure 6 This is a schematic diagram of a heat exchange energy storage box.

[0032] Figure 7 A schematic diagram of the module connection for setting up a circulating pump.

[0033] Figure 8 This is a schematic diagram of the hot water flow in the storage room with a circulating pump.

[0034] Figure 9 This is a schematic diagram of the hot water flow in a self-circulating state.

[0035] Figure 10 This is a flowchart illustrating a combined electric water heater control method provided in an embodiment of this application.

[0036] Explanation of reference numerals in the attached figures: 11. Main water inlet; 12. Main water outlet; 13. Instantaneous heating module branch; 14. Thermal storage module branch; 2. Flow sensor assembly; 3. Temperature sensor assembly; 4. First heating element; 5. Shut-off valve; 6. Energy storage tank; 61. Second heating element; 62. Heat exchanger; 7. Circulation pump. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0039] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0040] To address the existing technical problems of poor water quality, high energy consumption, easy overheating damage to components, poor flexibility in switching operating conditions, redundant heat storage structure, and simple control logic in series-connected combined electric water heaters, this application provides a combined electric water heater and its control method. The first aspect provides a parallel dual-branch combined electric water heater, which uses a parallel arrangement of instant heating module branches and heat storage module branches. Independent switching between the two branches is achieved using a shut-off valve. The instant heating branch can operate independently, or both branches can supply water simultaneously. A main controller is provided to link various sensing components and heating elements. The valve simplifies the heating structure of the heat storage tank, reducing the overall material cost. Secondly, it provides an intelligent control method adapted to the water heater, setting up two sets of operating logic: manual control and automatic control. In automatic mode, it collects the inlet water flow and temperature in real time, autonomously determines the water load and switches the water circuit conditions. When there is no water use, it automatically preheats the energy storage tank to store energy. For small water volumes, only the instant heating branch is activated to achieve energy saving. For large water volumes, the dual modules operate simultaneously to increase the total hot water output. It can also be equipped with a circulating pump to enhance the heat storage and heat exchange efficiency. The heat exchange energy storage tank isolates the bathing water from the heat storage medium, further improving the quality of the output water.

[0041] Please see Figure 1 , Figure 2 as well as Figure 3 This application provides a combined electric water heater, including: a main inlet water line 11, a main outlet water line 12, a main controller, a flow sensing component 2, a temperature sensing component 3, and a parallel-arranged instant heating module branch line 13 and a heat storage module branch line 14, the two branches converging and connecting to the main outlet water line 12; the instant heating module branch line 13 is provided with a first heating element 4, and the heat storage module branch line 14 is provided with a shut-off valve 5 and an energy storage tank 6; the flow sensing component 2 is mounted on the main inlet water line 11 to collect the inlet water flow signal, and the temperature sensing component 3 is respectively mounted on the main inlet water line 11 and the main outlet water line 12 to collect the inlet water and outlet water temperature signals; the main controller is electrically connected to the flow sensing component 2, the temperature sensing component 3, the first heating element 4, and the shut-off valve 5, the main controller receives the signals collected by each sensor, and outputs control signals to adjust the working state of the first heating element 4 and the on / off state of the shut-off valve 5.

[0042] During implementation, the basic structure of the modular electric water heater is first fully described. The water circuit of the whole unit is divided into an inlet main line 11 and an outlet main line 12. At the end of the inlet main line 11, two parallel independent branches are formed, namely the instant heating module branch 13 and the heat storage module branch 14. The two branches merge at the end and connect to the outlet main line 12 to complete the water supply. A flow sensor component 2 is installed on the inlet main line 11 to collect the inlet water flow value in real time. Temperature sensor components 3 are installed on the inlet main line 11 and the outlet main line 12 respectively to continuously collect inlet water temperature and outlet water temperature data. The flow and temperature electrical signals collected by all sensor components are uniformly transmitted to the main controller. The main controller has signal parsing, logic operation and drive output functions. It establishes electrical signal connection with the first heating element 4 and the shut-off valve 5 inside the heat storage branch. The main controller outputs drive signals according to the data feedback from the sensors, freely controlling the start, stop and power adjustment of the first heating element 4, and simultaneously controlling the opening and closing of the shut-off valve 5, thereby switching the water supply status of the two parallel branches. In everyday low-flow water use scenarios, the main controller closes the shut-off valve 5, and the water flows only through the first heating element 4 inside the instant heating module branch 13 to achieve heating. The energy storage tank 6 does not participate in water circulation at all, and the water inside the tank will not flow out with the water flow, thus preventing scale and bacteria from entering the outgoing water. At the same time, there is no need to continuously reheat the energy storage tank 6, significantly reducing ineffective heat energy loss. In high-flow water use scenarios with multiple people showering continuously, the main controller opens the shut-off valve 5, and cold water is simultaneously diverted into two branches. The instant heating module branch 13 relies on the first heating element 4 to instantly heat the cold water, while the energy storage module branch 14 relies on the energy storage tank 6. The constant-temperature hot water stored in the unit is output through hot and cold water exchange. The two hot water lines are mixed at the main outlet 12 and supplied to users. The simultaneous output of hot water from both lines greatly increases the total hot water supply of the whole unit, meeting the needs of continuous water use for a long time. When the whole unit is not in use and the flow sensor component 2 detects that the flow in the pipeline is zero, the main controller keeps the shut-off valve 5 open. The two parallel branches, the shut-off valve 5, and the energy storage tank 6 together form a closed and leak-free circulating water circuit. The main controller starts the first heating element 4 to continuously heat the water in the pipeline. The hot water, which has a lower density, flows upward and the cold water, which has a higher density, sinks downward, continuously completing the heating and energy storage of the entire water in the energy storage tank 6. This basic parallel water circuit and intelligent electronic control linkage structure is completely different from the traditional series-type combined water heater. It achieves independent on / off control of the two branches from the water circuit structure, solving the core defects of the traditional series structure, such as the inability to isolate the energy storage tank, high energy consumption, and easy overheating damage of components. The whole machine can complete the dual functions of instant water supply and heat storage with only one set of basic heating elements, which greatly simplifies the hardware configuration of the whole machine and reduces the cost of component procurement and assembly. At the same time, daily small water usage completely isolates the stagnant water in the energy storage tank, improving the sanitary conditions of the water from the source. The whole machine is suitable for all household water use conditions, such as hand washing, vegetable washing, single shower, and continuous showering for multiple people, significantly improving the flexibility of use.

[0043] Please see Figure 4After the addition of a second heating element 61 inside the energy storage tank 6, the second heating element 61 is electrically connected to the main controller, which centrally manages its start and stop. When the unit enters the dual-module collaborative water supply mode, the main controller, in addition to starting the first heating element 4, simultaneously drives the second heating element 61 to work. The two sets of heating elements heat the water simultaneously, significantly improving the heat storage speed of the energy storage tank 6. Even in situations with low inlet water temperature or low-temperature inlet water in winter, it can quickly replenish the hot water supply and reduce fluctuations in outlet water temperature. During the daily standby pre-energy storage phase, the second heating element 61 can be started independently to quickly heat up the energy storage tank 6, shortening the heat storage waiting time. This structure is suitable for models with low-temperature inlet water in northern regions and large-capacity energy storage tanks 6, making up for the slow heating speed caused by relying solely on the first heating element 4 for self-circulation heat storage. It takes into account both rapid heat storage and the need for high-flow constant-temperature water output. Users do not need to wait a long time for hot water preheating in winter, significantly improving the overall user experience.

[0044] Please see Figure 5 , Figure 6 When the energy storage tank 6 adopts a heat exchange structure, a heat exchanger 62 is independently installed inside the tank, and the energy storage tank 6 cavity has separate reserved inlet and outlet pipes for the heat storage medium. In actual use, the user's cold shower water only flows through the internal pipes of the heat exchanger 62 and will not directly contact the hot water or heat storage medium stored inside the energy storage tank 6 cavity. The heat storage medium inside the tank can be recycled for a long time. The shower water and the heat storage medium are completely isolated, and calcium and magnesium ions in the water cannot form scale buildup inside the energy storage tank 6 cavity. The inside of the tank remains clean for a long time, greatly reducing the frequency of cleaning and maintenance of the whole machine. The heat storage medium can be replaced and adjusted according to the season and usage needs to further improve the heat storage and insulation effect. In the standby state, the heat loss rate of the heat storage medium inside the cavity is slow, reducing the energy consumption of repeated heating. The heat exchange energy storage structure realizes the separation of water medium, completely solving the pain points of scale buildup and water quality deterioration in traditional hot water storage tanks, extending the service life of the energy storage tank 6, and reducing the later maintenance cost of the whole machine.

[0045] Please see Figure 7 , Figure 8 as well as Figure 9After the addition of circulation pump 7 to branch circuit 14 of the thermal storage module, circulation pump 7 is also connected to the main controller for unified scheduling. Circulation pump 7, shut-off valve 5, energy storage tank 6, and first heating element 4 can be combined to form a closed self-circulating hot water storage circuit. During the pre-energy storage stage when the whole unit is not in use, the main controller starts circulation pump 7 to force the water inside the pipeline to circulate in a directional manner, breaking the limitation of heat exchange relying solely on natural convection due to the density difference between hot and cold water, accelerating the exchange rate of hot and cold water inside energy storage tank 6, resulting in better overall temperature uniformity of energy storage tank 6, and significantly shortening the time required to complete heat storage. Even large-capacity energy storage tank 6 can quickly complete heat storage. During the dual-module water supply operation, circulation pump 7 continuously promotes the replacement of water inside energy storage tank 6, ensuring that energy storage tank 6 stably outputs constant-temperature hot water, avoiding the problem of rapid emptying of hot water at the top of energy storage tank 6 and a sudden drop in outlet water temperature. The addition of circulation pump 7 is structurally compatible with large-capacity energy storage equipment, enhances the heat exchange efficiency of the closed water circuit, solves the problems of slow natural convection heat exchange and severe stratification of water temperature in large-volume tanks, and ensures stable water temperature during long-term use.

[0046] After the unit is equipped with the operator, the operator is electrically connected to the main controller. The operator surface has two types of operating mode switching buttons, corresponding to single instant heating module operation and dual-module collaborative operation water circuit modes, respectively. Users can manually press the buttons to send operating mode switching commands to the main controller. For daily washing, washing vegetables, and other small-volume water use, users can manually switch to single instant heating mode. Upon receiving the command, the main controller directly closes the shut-off valve 5, activating only the first heating element 4 for independent water supply. When multiple people are showering and require a large volume of hot water, a single button switch to dual-module collaborative mode is made, and the main controller automatically opens the shut-off valve 5 to simultaneously activate the two branch water supply lines. The manual operation mode eliminates the need to wait for sensor detection and judgment; users can actively switch water circuits according to their own water needs. The operation is intuitive and simple, allowing even the elderly and children to quickly learn how to use it. It adapts to the operating habits of different users, compensating for the delay issues inherent in the automatic mode's predictive logic. The manual and automatic control methods complement each other, significantly improving the overall human-machine interaction convenience of the unit.

[0047] Please see Figure 10The control method of this invention is based on the aforementioned hardware structure and is equipped with two independent operating logics: manual and automatic. The entire control process covers all operating conditions, including daily water use and standby heat storage. In manual mode, the operator receives user commands, and the main controller directly controls the opening and closing of the shut-off valve 5 and the start and stop of the first heating element 4 according to the commands. The command response speed is fast, meeting the user's need for immediate switching of operating conditions. In automatic mode, the flow sensor component 2 and the temperature sensor component 3 continuously collect real-time inlet water flow and inlet water temperature data. The main controller retrieves the preset target outlet water temperature in the system to perform heat calculation. It accurately calculates whether the current cold water can be heated to the set temperature by relying solely on the first heating element 4 running at full power. If the heat supply is sufficient, the shut-off valve 5 is closed and only the instant hot water branch is used to supply water, saving the heat dissipation energy consumption of the heat storage branch. If the heat is insufficient, the shut-off valve 5 is opened, and the two branches simultaneously supply water, thus increasing the hot water supply. When the whole machine detects no water flow, it automatically opens the shut-off valve 5 to form a closed circulation water circuit and starts the first heating element 4 to continuously preheat the energy storage tank 6, storing hot water in advance so that constant temperature hot water can be quickly output when water is used later. The entire automatic control logic relies on real-time sensor data to intelligently determine the operating conditions without manual intervention. It automatically matches the heating output with the water circuit, taking into account both energy saving and water output stability. At the same time, the standby pre-storage function eliminates the problem of users waiting for hot water, adapting to the all-day water needs of various families.

[0048] When the energy storage tank 6 is equipped with the second heating element 61, the control method simultaneously starts the first heating element 4 and the second heating element 61 during the dual-module collaborative water supply stage. The two sets of heating elements output heat simultaneously, which greatly improves the total heating power of the whole machine. Even in low-temperature water inlet and high-flow water outlet scenarios, the water temperature can still be stably maintained without the water temperature continuously dropping. When the water inlet temperature is extremely low in winter, the simultaneous operation of the two heating elements can quickly make up for the heat gap, reduce water outlet temperature fluctuations, and increase the continuous bathing time. It is suitable for use in low-temperature environments in the north and solves the problems of insufficient power limit of a single heating element and substandard water temperature when the water flow is high.

[0049] For models equipped with a circulating pump 7 in the thermal storage branch, the control method involves simultaneously activating the circulating pump 7 during both the dual-module water supply and standby preheating stages. The pump's thrust forces the water inside the pipeline to circulate in a directional manner, accelerating the exchange of hot and cold water in the energy storage tank 6. This shortens the tank's heat storage time during the pre-storage stage and ensures a continuous and uniform output of hot water from the energy storage tank 6 during the water supply stage. This avoids water temperature stratification inside the tank and the phenomenon of hot water turning cold at the outlet. The water temperature stability of models with large-capacity energy storage tank 6 is significantly improved, resulting in minimal fluctuations in outlet water temperature during long-term continuous bathing and a higher level of bathing comfort.

[0050] For models without a circulation pump 7 in the heat storage branch, the control method does not activate external circulation equipment. Instead, it relies on natural convection formed by the density difference between the hot and cold water to heat the energy storage tank 6. During the standby pre-storage phase, after the first heating element 4 heats the surrounding water, the hot water naturally floats upward, while the cold water at the bottom of the tank continuously sinks to the heating area. Relying on the density difference of the water itself, a continuous internal circulation is formed, gradually heating up the entire tank of water. This control logic does not require driving the pump, reducing energy consumption during standby. The simplified structure and control logic of this model result in fewer potential failure points, making it suitable for small apartments and low-capacity water heaters. While meeting basic heat storage functions, it reduces the overall standby energy consumption and hardware costs.

[0051] Throughout the entire operation of the machine, the outlet water temperature sensor continuously collects the real-time water temperature of the main outlet water channel 12. The main controller dynamically adjusts the output power of the first heating element 4 and the second heating element 61 based on the collected temperature values. When the outlet water temperature is higher than the set target value, the heating power is reduced, and when the outlet water temperature is lower, the heating power is increased. The real-time closed-loop control of the outlet water temperature avoids the problem of sudden changes in water temperature caused by fluctuations in water flow and changes in inlet water temperature. The outlet water temperature is kept stable within the user-set range throughout the process, greatly improving the bathing water experience. Users do not need to repeatedly manually adjust the gear, and the overall temperature control accuracy is higher.

[0052] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0053] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0055] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0056] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0057] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0058] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Since these modifications and variations fall within the scope of the claims and their equivalents, this application also intends to include these modifications and variations.

[0059] The above description describes specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A combined electric water heater, characterized in that, include: The system includes an inlet main line, an outlet main line, a main controller, flow sensing components, temperature sensing components, and parallel-arranged instant heating module branches and thermal storage module branches, with the two branches converging and connecting to the outlet main line. The instant heating module branch is equipped with a first heating element, and the heat storage module branch is equipped with a shut-off valve and an energy storage box. The flow sensing component is mounted on the main inlet water line to collect the inlet water flow signal, and the temperature sensing component is mounted on the main inlet water line and the main outlet water line to collect the inlet water and outlet water temperature signals, respectively. The main controller is electrically connected to the flow sensing component, temperature sensing component, first heating element, and shut-off valve respectively. The main controller receives the signals collected by each sensor and outputs control signals to adjust the working state of the first heating element and the on / off state of the shut-off valve.

2. The combined electric water heater according to claim 1, characterized in that, The energy storage box is equipped with a second heating element, which is electrically connected to the main controller and is controlled to start and stop by the main controller.

3. The combined electric water heater according to claim 1, characterized in that, The thermal storage module branch is also equipped with a circulation pump, which is electrically connected to the main controller. The circulation pump, shut-off valve, energy storage tank and first heating element can work together to form a closed self-circulating hot water storage circuit.

4. The combined electric water heater according to claim 2, characterized in that, The energy storage box has a heat exchange structure and is equipped with a heat exchanger inside. The energy storage box cavity is equipped with a medium pipeline for the heat storage medium to enter and exit.

5. The combined electric water heater according to claim 1, characterized in that, It also includes an operator, which is electrically connected to the main controller. The operator is equipped with operation buttons for switching between two water circuit operating conditions: single instant heating module and dual module coordinated operation. The operator sends operating condition switching commands to the main controller.

6. A control method for a combined electric water heater, characterized in that, The combined electric water heater described in any one of claims 1 to 5 includes a manual control mode and an automatic control mode. The manual control mode involves the user selecting either a single instant heating module or a dual-module collaborative mode via an operator, and the main controller correspondingly controls the opening and closing of the shut-off valve and the start and stop of the first heating element. The automatic control mode involves the flow sensor and temperature sensor collecting the inlet water flow and inlet water temperature in real time. The main controller calculates whether the cold water can be heated to the target temperature using only the first heating element based on the preset target outlet water temperature. If the target temperature can be met, the shut-off valve is closed and only the instant heating module branch is used for water supply. If the target temperature cannot be met, the shut-off valve is opened and both branches are used for water supply simultaneously. When there is no water flow in the whole unit, the main controller opens the shut-off valve, forms a closed circulation water circuit based on the two parallel branches, and starts the first heating element to pre-heat the water inside the energy storage tank.

7. The control method for a combined electric water heater according to claim 6, characterized in that, When the energy storage box is equipped with a second heating element, the first heating element and the second heating element are activated simultaneously in the dual-module collaborative working state.

8. The control method for a combined electric water heater according to claim 6, characterized in that, When the thermal storage branch is equipped with a circulation pump, the circulation pump is activated simultaneously during the dual-module water supply and energy storage preheating processes to force water circulation and heat exchange.

9. The control method for a combined electric water heater according to claim 6, characterized in that, When the thermal storage branch is not equipped with a circulation pump, the control water circuit relies on the temperature difference of the water itself to form a natural convection circulation, thereby achieving uniform heating of the water in the energy storage tank.

10. The control method for a combined electric water heater according to claim 6, characterized in that, The main controller adjusts the power of the heating element based on the real-time water temperature collected by the outlet water temperature sensor to maintain a stable outlet water temperature.

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