Combined electric water heater

Abstract

The invention relates to the field of household appliances, aims to overcome the defects of an existing electric water heater, and provides a combined electric water heater integrating water storage and quick heating functions. The device comprises a heat storage water tank, an immersed heat exchange path, an integrated water mixing unit which is not in a completely closed state, a power-adjustable main heating module, a sewage draining exit with an integrated exhaust pipe and an intelligent control system, and switching of four modes of single cooling / single heating (supporting flow reduction), water mixing and water supplementing can be achieved. Through closed-loop temperature control and heating load dynamic distribution, the water heater is efficient and energy-saving, the water temperature is stable, the problems of water scale and repeated boiling water in water storage heating are solved, safety and reliability are achieved, remote control is supported, and the water heater is suitable for families, small commercial places and other scenes.

Description

Technical Field

[0001] This invention relates to the field of household appliance technology. In particular, it relates to a combined electric water heater that integrates storage and instant heating functions. Specifically, it is a multi-functional electric water heater system capable of intelligently switching operating modes according to actual water demand, achieving high efficiency, energy saving, and safe and stable operation. This system is not only suitable for daily household bathing and kitchen water use, but can also be widely applied in small commercial spaces, apartment buildings, guesthouses, and other environments with high flexibility and energy efficiency requirements for hot water supply. Background Technology

[0002] With the improvement of people's living standards and the enhancement of energy conservation awareness, the performance requirements for household hot water equipment are increasing. Currently, electric water heaters on the market are mainly divided into two types: storage type and instantaneous type. Storage type electric water heaters preheat and store the water in the tank through a built-in heating element, and release hot water directly when in use. Its advantages are stable water pressure, relatively low power consumption, and low installation threshold. However, it has obvious drawbacks, such as large size, long waiting time due to long preheating time, and energy waste due to continuous heat preservation during non-use periods (i.e., "repeated heating" or "repeatedly boiled water" phenomenon). In addition, the problem of insufficient or excessive hot water is prone to occur with changes in usage frequency.

[0003] In addition, tap water contains dissolved calcium carbonate and other limescale substances. When a storage water heater is used for a long time, the water in the storage tank is heated and the water temperature rises, causing the calcium carbonate and other inorganic substances to precipitate. This mixed with microorganisms killed by the high temperature of the hot water forms a gel-like limescale that accumulates more and more. First, it affects the quality of the water used for bathing; second, it adheres to the surface of the heating element, affecting the heat transfer between the heating element and the water, and causing damage to the heating element.

[0004] Electric water heaters use high-power instantaneous heating technology, which rapidly heats up water as it flows through the heating element, achieving "instant hot water." They have advantages such as small size, no need for water storage, and no heat preservation energy consumption. However, their instantaneous power is extremely high, placing extremely high demands on the household circuit load, which is difficult for ordinary residential circuits to handle. At the same time, in winter when the inlet water temperature is low or the water flow is high, they often cannot reach the set outlet water temperature, affecting the user experience.

[0005] To overcome the shortcomings of the aforementioned single-mode design and combine the advantages of both, some composite electric water heater designs integrating heat storage and rapid heating functions have emerged in recent years. However, these designs are typically complex in structure, lack precise control over the mixing of hot and cold water, and fail to effectively address safety and efficiency issues such as water replenishment, venting, and anti-dry-burning of the storage tank. For example, some products, while equipped with a preheating function, lack an effective hot and cold water mixing regulation mechanism, resulting in unstable preheating effects; some designs have simple mixing valve structures, only possessing on / off or fixed-ratio mixing functions, unable to achieve dynamic adjustment, and difficult to adapt to the needs of multi-point water use and multi-scenario switching; some designs neglect precise monitoring of the water level inside the storage tank or lack linkage control with the mixing system, easily leading to untimely water replenishment or overflow risks, posing safety hazards; venting design is also often overlooked, causing air accumulation that affects heat exchange efficiency and may even lead to dry-burning hazards; some designs require the use of pressurized water tanks, which prevents the improvement of product space utilization and the achievement of a small volume with equal volume; some designs place the entire heat exchanger inside the heat storage medium without considering the heat distribution within the storage medium.

[0006] In addition, most existing mixing valves have a shut-off function, which may cut off the water flow under abnormal operating conditions, affecting the user experience. At the same time, when the valve is shut off, the valve discs are in a ceramic-bonded state, and the pressure difference between the holes is different. Electric mixing valves require greater torque to open. If the valve remains in the shut-off state for too long, the long-term pressure and prolonged bonding may cause the electric mixing valve to fail to open. While some high-end products can drain stagnant water, they require additional drain outlets, resulting in structural redundancy.

[0007] In addition, most combination water heaters on the market do not have the function of reducing water flow. When the heat storage energy and the fast heating power cannot meet the power requirements of the user's flow rate, the water heater will drop in temperature sharply. At this time, the user needs to manually adjust the water inlet, which can easily affect the user experience. Summary of the Invention

[0008] Based on the current situation, the purpose of this invention is to overcome the shortcomings of existing electric water heaters in terms of energy efficiency, safety, response speed, and applicability, and to provide a combined electric water heater with a reasonable structure, intelligent control, and efficient operation. This device innovatively integrates a heat storage heating unit, a high-efficiency heat exchange path, a multi-mode integrated mixing unit, and an adjustable power main heating module, supplemented by precise sensor monitoring and an intelligent control system. This enables adaptive adjustment to different water usage conditions, maximizing the utilization of existing thermal energy, reducing overall energy consumption, improving water comfort and safety, and solving problems such as repeatedly boiled water and heating delays, thus meeting the comprehensive needs of modern families for green, intelligent, and efficient hot water systems.

[0009] To achieve the above objectives, the present invention provides a combined electric water heater, the specific technical solution of which is as follows:

[0010] A combined electric water heater includes: a hot water storage tank, a heat storage heating element, a heat exchange path, an integrated mixing unit, a main heating module, a drain outlet, and a control system. The structure and connection relationship of each component are as follows:

[0011] The hot water storage tank, as a thermal energy storage center, defines the liquid storage space and is filled with a thermal storage medium (water). The outer wall of the hot water storage tank is wrapped with a high-performance insulation layer, such as polyurethane foam or vacuum insulation board, to effectively slow down heat loss and maintain the high temperature of the thermal storage medium inside the tank. The hot water storage tank is equipped with a water supply pipe to replenish the thermal storage medium to the liquid storage space, ensuring long-term stable operation.

[0012] Preferably, the heat storage medium may include a phase change material, not just water, and the phase change material can indirectly absorb and release heat through water.

[0013] The heat storage heating element is located inside the hot water storage tank. It only heats the heat storage medium and does not directly participate in the final heating process of the external water supply. It provides a heat source for subsequent heat exchange. Its operation is controlled by the control system based on feedback from the water tank temperature sensor to avoid overheating and energy waste.

[0014] Preferably, the heat storage heating element is located in the bottom area of ​​the hot water storage tank to promote heat circulation through natural convection, improve heating uniformity, and enhance heating efficiency.

[0015] The heat exchange path is completely submerged in the heat storage medium, and a water flow channel is formed inside it. When tap water flows through the heat exchange path, the water flows through the metal pipe wall to carry out efficient non-contact heat exchange with the high-temperature heat storage medium, thereby achieving preheating of cold water.

[0016] Preferably, the heat exchange path is a tubular structure, with its outer wall in direct contact with the heat storage medium and its inner wall in contact with the water flow. The outer pipe wall of the water outlet section of the heat exchange path is wrapped with heat insulation material. In this way, the water outlet section of the heat exchange path passes through a low-temperature region, which can prevent reverse heat exchange, reduce heat loss in the water outlet section, and ensure the preheating effect.

[0017] More preferably, the heat exchange path is made of copper or stainless steel, which has excellent thermal conductivity, and its structure can be designed as a corrugated coil, a serpentine tube, or a multi-pass straight tube, which can increase the contact area with the heat storage medium and improve the heat exchange efficiency.

[0018] The integrated mixing unit includes a cold water inlet pipe, a cold water outlet pipe, a hot water inlet pipe, a mixing outlet pipe, a makeup water outlet pipe, a mixing valve core, and a drive module, wherein:

[0019] The cold water inlet pipe is used to connect to external cold water, allowing external tap water to enter the integrated mixing unit;

[0020] The cold water output pipe is connected to the inlet end of the heat exchange path, and the cold water in the integrated mixing unit enters the cold inlet end of the heat exchange path from this port.

[0021] The hot water input pipe is connected to the outlet end of the heat exchange path. After the tap water absorbs heat from the heat storage medium and increases its temperature through the heat exchange path, it enters the integrated mixing unit through the hot water input pipe.

[0022] The mixed water output pipe outputs the mixed water, which enters the main heating module for secondary heating.

[0023] The water supply outlet pipe is connected to the water inlet of the water supply pipe, and tap water replenishes the heat storage medium (water) through this port.

[0024] The mixing valve core is a multi-channel rotary switching element with multiple throttling orifices and connecting chambers inside. It is connected to the cold water inlet pipe, the hot water inlet pipe, the mixing outlet pipe, and the makeup water outlet pipe, respectively. It can change the connection relationship and flow distribution ratio between the pipes by rotating. The key feature is that the valve core is designed without a completely closed state, that is, there is a set of channels connected in any switching position; so that it will not siphon and stick together in the closed state, which would increase the driving load of the drive module.

[0025] The drive module, consisting of a stepper motor or a servo motor, is mechanically connected to the rotating handle of the mixing valve core. It receives commands from the control system and precisely drives the mixing valve core to rotate to a specified angle, thereby achieving automatic switching between different working modes.

[0026] The main heating module is located after the integrated mixing unit. Its inlet end is connected to the mixing output pipe, and its outlet end is connected to the user's water supply line. It is used to reheat the mixed low-temperature water to ensure that the outlet water temperature meets the user's needs and improve the user experience.

[0027] Preferably, the main heating module is a fast-heating electric heating element with rapid heating and adjustable power. It can dynamically adjust the heating power according to the initial temperature of the incoming water and the target outlet water temperature to complete the final temperature control compensation and ensure constant outlet water temperature.

[0028] A drain outlet is located at the bottom of the hot water storage tank to periodically remove scale and other impurities deposited inside. Specifically, a hollow vent pipe is integrated within the drain outlet. The upper end of the vent pipe connects to the gas phase space above the surface of the heat storage medium in the liquid storage space, while the lower end is open to the atmosphere. This structure utilizes the drain pipe to achieve dual functions—drainage and automatic venting—ensuring pressure balance in the gas phase space within the hot water storage tank and preventing excessively high or low pressure. Since the non-pressurized water tank only needs to withstand the weight of its own water, its external dimensions do not need to adhere to the cylindrical shape of the pressurized water tank; it can adopt irregular shapes, effectively utilizing the internal space of the water heater casing.

[0029] The control system, serving as the central control hub of the entire unit, integrates a microprocessor, memory, input interfaces (such as a user operation panel), communication module (supporting Wi-Fi / Bluetooth, etc.), and multiple sensor signal acquisition channels. It is configured to dynamically allocate the heating load between the thermal storage heating element and the main heating module based on water usage parameters, and to control the operation of the drive module, achieving intelligent control and optimal energy efficiency.

[0030] Furthermore, the hot water storage tank is equipped with high-level and low-level probes to monitor the liquid level of the heat storage medium. This prevents excessive overflow or insufficient liquid level from exposing the heat exchange path and reducing conduction efficiency. When the liquid level is below the low-level probe, the drive module can activate the mixing valve core to switch to the water injection mode for water injection or replenishment. When the liquid level reaches the high-level probe, the drive module can activate the mixing valve core to switch away from the water replenishment mode to stop water injection or replenishment. The outlet of the water replenishment pipe is positioned higher than the high-level probe to ensure that the heat storage medium does not flow back after water replenishment. The upper opening of the vent pipe is positioned higher than the high-level probe to ensure that the vent pipe is always connected to the gas phase space, ensuring stable pressure balance and structural stability of the non-pressurized water tank.

[0031] Furthermore, the cold water inlet pipe is equipped with a cold water inlet temperature sensor and a flow sensor to detect the cold water inlet temperature and flow rate, and to feed the temperature and flow rate signals back to the control system, providing data support for the dynamic distribution of heating load and the mixing drive of the integrated mixing unit.

[0032] Furthermore, the integrated mixing unit can control the mixing valve core through the drive module to achieve multiple operating modes:

[0033] —Single cold water mode: The mixing valve core connects the cold water inlet pipe and the mixing outlet pipe, cutting off the hot water input. The water flow does not pass through the heat exchange path and directly enters the main heating module for heating. At this time, the main heating module can be used to directly heat the water, which is suitable for summer or high-flow-rate use scenarios that require low-temperature water.

[0034] —Single hot water mode: The mixing valve core connects the hot water input pipe and the mixing output pipe. All water flows through the heat exchange path for preheating before entering the main heating module, achieving maximum energy efficiency. In single hot water mode, the drive module can further fine-tune the opening of the mixing valve core, reducing the total flow rate into the main heating module. This increases the outlet water temperature while maintaining the main heating power, or reduces the heating load while keeping the temperature constant. Alternatively, when all tap water is preheated through the heat exchange path before entering the main heating module for secondary heating, and the power of the main heating module is insufficient to support the user's required temperature, the drive module can drive the mixing valve core to reduce the water flow rate, thereby increasing the water temperature to meet the user's required temperature, until it is lower than the water flow rate when the water heater starts.

[0035] —Mixing Mode: Simultaneously connect the cold water input pipe and the hot water input pipe to the mixing output pipe, mix the preheated water flow with the original cold water flow according to a set ratio, adjust the initial water temperature entering the main heating module, and adapt to different seasons and water usage habits; when the temperature of the tap water entering the main heating module after preheating through the heat exchange path is higher than the user's required temperature, the mixing valve core can be driven by the drive module to mix cold water to reduce the temperature entering the main heating module; when the temperature of the tap water entering the main heating module after preheating through the heat exchange path is lower than the user's required temperature but higher than the pre-heating temperature (the pre-heating temperature is the user's required temperature minus the maximum temperature rise that the main heating module can provide), the mixing valve core can be driven by the drive module to mix cold water to reduce the temperature entering the main heating module or reduce the real-time heating power of the main heating module;

[0036] —Water replenishment mode: Connect the cold water inlet pipe and the water replenishment outlet pipe to inject replenishing water into the hot water storage tank; after the water heater is installed, connect the water source and power supply, and the water heater will first detect the high liquid level probe and the low liquid level probe. When the liquid level is lower than the low liquid level probe, the drive module can drive the mixing valve core to switch to the water replenishment mode to inject or replenish water; when the liquid level reaches the high liquid level probe, the drive module can drive the mixing valve core to switch away from the water replenishment mode to stop injecting or replenishing water.

[0037] Furthermore, the hot water storage tank is equipped with a water temperature sensor, which is located in the upper middle part of the liquid storage space. The sensor is used to detect the temperature of the heat storage medium and feed it back to the control system to control the start and stop of the heat storage heating element and ensure that the temperature of the heat storage medium is stable within the set range.

[0038] Furthermore, the control system uses the temperature of the heat storage medium fed back by the water storage temperature sensor to control the integrated mixing unit for water mixing pre-adjustment, thereby improving the stability of the user's required temperature. The integrated mixing unit is also equipped with a mixing temperature sensor to detect the temperature of the mixed water and feed it back to the control system, thereby realizing closed-loop control of the water temperature and optimizing the response speed of the main heating module.

[0039] Furthermore, the control system can be connected to a smart home platform, supporting functions such as remote control via mobile APP, scheduled heating, and energy consumption statistics, thus meeting the development trend of smart homes.

[0040] Compared with the prior art, the combined electric water heater of the present invention has the following advantages:

[0041] High heat exchange efficiency: By setting up a heat exchange path immersed in the heat storage medium, especially the corrugated coil structure, the heat exchange contact area is increased; at the same time, the outer wall of the heat exchange outlet section is wrapped with heat insulation material, which reduces heat loss and significantly improves heat exchange efficiency.

[0042] Precise water temperature regulation and rapid temperature control: The integrated mixing unit enables flexible mixing of hot and cold water. With dual monitoring from both the storage water temperature sensor and the integrated mixing unit temperature sensor, the control system can precisely adjust the mixing ratio and heating power based on feedback data to ensure stable outlet water temperature.

[0043] Flexible operating modes: The integrated mixing unit can flexibly switch between four operating modes: cold water only, hot water only, mixing water, and water replenishment, to adapt to different water use scenarios (such as washing, showering, cleaning, etc.); in hot water only mode, the water flow rate can be reduced to extend the usage time of the combination water heater and further improve the convenience of use.

[0044] Energy-saving and stable: The control system can dynamically allocate the heating load of the thermal storage heating element and the main heating module according to water parameters (such as flow rate and temperature), and has pre-adjusted the integrated mixing unit to avoid energy waste; at the same time, the setting of structures such as liquid level probe and exhaust pipe improves the stability and safety of equipment operation.

[0045] Intelligent Adaptive: The control system can automatically select the optimal working mode based on parameters such as season, water consumption, and inlet water temperature to achieve "on-demand heating" and improve user experience.

[0046] Safe and reliable operation: Through multiple designs such as liquid level probe, venting structure and non-closing mixing valve core, it effectively prevents safety hazards such as overpressure and air blockage, and ensures long-term stable operation.

[0047] Highly integrated structure: It organically integrates functional modules such as heat storage, preheating, water mixing, rapid heating, water replenishment, and venting, simplifying the pipeline layout, reducing the overall size of the unit, and facilitating installation and maintenance.

[0048] Improved water quality experience: The water in the hot water storage tank is not directly output but is used only as a heat transfer medium, avoiding the problem of "repeatedly boiled water" and resulting in cleaner and fresher output water.

[0049] Supports remote intelligent management: The control system can be connected to a smart home platform, supporting functions such as remote control via mobile APP, scheduled heating, and energy consumption statistics, meeting the development trend of smart homes. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the structure of the combined electric water heater of the present invention;

[0051] Figure 2 This is a schematic diagram of the internal structure of the hot water storage tank and the heat exchange path of the present invention;

[0052] Figure 3 One of the structural schematic diagrams of the integrated mixing unit of the present invention;

[0053] Figure 4 The second schematic diagram of the integrated mixing unit of the present invention;

[0054] in, Figures 1 to 4 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0055] 1. Hot water storage tank; 2. Heat storage heating element; 3. Heat exchange path; 4. Integrated mixing unit; 5. Main heating module; 6. Drain outlet; 7. Control system; 8. Water supply pipe; 9. Insulation layer; 10. Cold water input pipe; 11. Cold water output pipe; 12. Hot water input pipe; 13. Mixing water output pipe; 14. Water supply output pipe; 15. Mixing valve core; 16. Drive module; 17. Exhaust pipe; 18. High liquid level probe; 19. Low liquid level probe; 20. Flow sensor; 21. Water storage temperature sensor; 22. Mixing water temperature sensor; 23. Cold water temperature sensor; 24. Insulation material. Detailed Implementation

[0056] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0057] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0058] The following reference Figures 1 to 4 A combination electric water heater according to some examples of the present invention is described.

[0059] A combined electric water heater includes: a hot water storage tank 1, a heat storage heating element 2, a heat exchange path 3, an integrated mixing unit 4, a main heating module 5, a drain outlet 6, and a control system 7. The structure and connection relationship of each component are as follows:

[0060] The hot water storage tank 1 has a square box structure and serves as a heat energy storage center, defining the liquid storage space. The interior is filled with a heat storage medium (water). The outer wall of the hot water storage tank 1 is wrapped with a high-performance vacuum insulation board insulation layer 9 with a thickness of 10mm to effectively reduce heat loss and maintain the high temperature of the heat storage medium inside the tank. The hot water storage tank 1 is equipped with a water supply pipe 8 for replenishing the heat storage medium to the liquid storage space to ensure long-term stable operation.

[0061] Preferably, the heat storage medium may include a phase change material, not just water, and the phase change material can indirectly absorb and release heat through water.

[0062] The heat storage heating element 2, made of stainless steel with a power of 5000W, is located inside the hot water storage tank 1 and is fixedly connected to the hot water storage tank 1 by flange welding. Its wiring terminals extend to the outside of the hot water storage tank 1 and are electrically connected to the control system 7. It is only used to heat the heat storage medium and does not directly participate in the final heating process of the external water supply, but provides a heat source for subsequent heat exchange. Its operation is controlled by the control system 7 based on the feedback from the water tank temperature sensor 21 to start and stop, avoiding overheating and energy waste.

[0063] Preferably, the heat storage heating element 2 is disposed in the bottom area of ​​the hot water storage tank 1 so as to promote heat circulation by utilizing natural convection, improve heating uniformity, and enhance heating efficiency.

[0064] The heat exchange path 3 is completely submerged in the heat storage medium, and a water flow channel is formed inside it. When tap water flows through the heat exchange path 3, the water flows through the metal pipe wall and performs efficient non-contact heat exchange with the high-temperature heat storage medium to achieve preheating of cold water.

[0065] Preferably, the heat exchange path 3 is a tubular structure, with its outer wall in direct contact with the heat storage medium and its inner wall in contact with the water flow. The outer pipe wall of the water outlet section of the heat exchange path 3 is wrapped with 24mm thick heat insulation material. In this way, the water outlet section of the heat exchange path 3 passes through a low-temperature area, which can prevent reverse heat exchange, reduce heat loss in the water outlet section, and ensure the preheating effect.

[0066] More preferably, the heat exchange path 3 is made of stainless steel with excellent thermal conductivity and has a corrugated coil structure, which can increase the contact area with the heat storage medium and improve the heat exchange efficiency. The water inlet end of the corrugated coil is connected to the cold water output pipe 11 of the integrated mixing unit 4 through a pipe, and the water outlet end is connected to the hot water input pipe 12 of the integrated mixing unit 4 through a pipe.

[0067] The integrated mixing unit 4 includes a cold water inlet pipe 10, a cold water outlet pipe 11, a hot water inlet pipe 12, a mixing outlet pipe 13, a makeup water outlet pipe 14, a mixing valve core 15, and a drive module 16, wherein:

[0068] The cold water inlet pipe 10 is used to connect to external cold water, so that external tap water enters the integrated mixing unit.

[0069] The cold water output pipe 11 is connected to the inlet end of the heat exchange path 3, and the cold water in the integrated mixing unit 4 enters the cold inlet end of the heat exchange path 3 from this port.

[0070] The hot water input pipe 12 is connected to the outlet end of the heat exchange path 3. After the tap water absorbs heat from the heat storage medium and raises its temperature through the heat exchange path, it enters the integrated mixing unit 4 through the hot water input pipe 12.

[0071] The mixed water output pipe 13 outputs the mixed water, which enters the main heating module 5 for secondary heating.

[0072] The water supply outlet pipe 14 is connected to the water inlet of the water supply pipe 8, and tap water replenishes the heat storage medium (water) through this port.

[0073] The mixing valve core 15 is a ceramic valve core, a multi-channel rotary switching element with multiple throttling orifices and connecting chambers inside. It is connected to the cold water inlet pipe 10, hot water inlet pipe 12, mixing outlet pipe 13, and water supply outlet pipe 14, respectively. It can change the connection relationship and flow distribution ratio between the pipes by rotation. The key feature is that the valve core is designed without a completely closed state, that is, there is a set of channels connected in any switching position; so that it will not siphon and stick due to the closed state, which would increase the driving load of the drive module 16.

[0074] The drive module 16, consisting of a stepper motor and equipped with a reset Hall sensor, is mechanically connected to the rotating handle of the mixing valve core 15. It receives commands from the control system 7 and precisely drives the mixing valve core 15 to rotate to a specified angle, thereby achieving automatic switching between different working modes.

[0075] The main heating module 5 is located after the integrated mixing unit 4. Its inlet end is connected to the mixing output pipe 13, and its outlet end is connected to the user's water supply line. It is used to reheat the mixed low-temperature water to ensure that the outlet water temperature meets the user's needs and improve the user experience.

[0076] Preferably, the main heating module 5 is a fast-heating electric heating element with rapid heating and adjustable power. The power adjustment range is 0-5500W. The heating power can be dynamically adjusted according to the initial temperature of the incoming water and the target outlet water temperature to complete the final temperature control compensation and ensure constant outlet water temperature.

[0077] A drain outlet 6 is located at the bottom of the hot water storage tank 1 and is used to periodically discharge scale and other impurities deposited in the hot water storage tank 1. In particular, a hollow exhaust pipe 17 is integrated into the drain outlet. The upper end of the exhaust pipe 17 is connected to the gas phase space above the liquid surface of the heat storage medium in the liquid storage space, and the lower end is connected to the atmosphere. This structure uses the drain pipe to achieve dual functions - draining and automatic venting, which can achieve pressure balance in the gas phase space inside the hot water storage tank 1 and avoid excessively high or low pressure. Since the non-pressurized water tank only needs to bear the pressure of its own water weight, its shape does not need to be restricted to the cylindrical shape of the pressurized water tank. It can adopt irregular shapes, which can effectively utilize the space inside the water heater shell.

[0078] The control system 7, serving as the central control unit of the entire system, integrates a microprocessor, memory, input interfaces (such as a user operation panel), communication module (supporting Wi-Fi / Bluetooth, etc.), and multiple sensor signal acquisition channels. It is configured to dynamically allocate the heating load between the thermal storage heating element 2 and the main heating module 5 based on water usage parameters and to control the operation of the drive module 16, achieving intelligent control and optimal energy efficiency.

[0079] Furthermore, the hot water storage tank 1 is equipped with a high-level probe 18 and a low-level probe 19 to monitor the liquid level of the heat storage medium, preventing excessive overflow or insufficient heat storage medium from exposing the heat exchange path and reducing conduction efficiency. When the liquid level is lower than the low-level probe 19, the drive module 16 can drive the mixing valve core 15 to switch to the water replenishment mode to inject or replenish water. When the liquid level reaches the high-level probe 18, the drive module 16 can drive the mixing valve core 15 to switch away from the water replenishment mode to stop injecting or replenishing water. The outlet of the water replenishment pipe 8 is higher than the high-level probe 18 to ensure that the heat storage medium does not flow back after water replenishment. The upper opening of the exhaust pipe 17 is higher than the high-level probe 18 to ensure that the exhaust pipe is always connected to the gas phase space, ensuring stable pressure balance function and structural stability of the non-pressurized water tank.

[0080] Furthermore, the cold water input pipe 10 is equipped with a cold water temperature sensor 23 (model: NTC) and a flow sensor 20, which are used to detect the cold water input temperature and flow rate, and feed the temperature and flow rate signals back to the control system 7, providing data support for the dynamic distribution of heating load and the mixing drive of the integrated mixing unit 4.

[0081] Furthermore, the integrated mixing unit 4 can control the mixing valve core 15 through the drive module 16 to achieve multiple operating modes:

[0082] —Single cold water mode: The mixing valve core 15 connects the cold water inlet pipe 10 and the mixing outlet pipe 13, cuts off the hot water input, and the water flow does not pass through the heat exchange 3 path, but directly enters the main heating module 5 for heating. At this time, the main heating module 5 can be used to directly heat the water, which is suitable for summer or high-flow-rate use scenarios that require low-temperature water.

[0083] —Single hot water mode: The mixing valve core 15 connects the hot water input pipe 12 and the mixing output pipe 13. All water flows through the heat exchange path 3 for preheating before entering the main heating module 5, achieving maximum energy efficiency. In single hot water mode, the drive module 16 can further fine-tune the opening of the mixing valve core 15, reducing the total flow rate into the main heating module 5. This increases the outlet water temperature while maintaining the main heating power, or reduces the heating load while keeping the temperature constant. Alternatively, when all tap water is preheated through the heat exchange path 3 before entering the main heating module 5 for secondary heating, and the power of the main heating module 5 is insufficient to support the user's required temperature, the drive module 16 can drive the mixing valve core 15 to reduce the water flow rate, thereby increasing the water temperature to meet the user's required temperature, until it is lower than the water flow rate when the water heater starts.

[0084] —Mixing Mode: Simultaneously connects the cold water input pipe 10 and the hot water input pipe 12 to the mixing output pipe 13, mixing the preheated water flow with the original cold water flow according to a set ratio, adjusting the initial water temperature entering the main heating module 5 to adapt to different seasons and water usage habits; when the temperature of the tap water entering the main heating module 5 after preheating through the heat exchange path 3 is higher than the user's required temperature, the mixing valve core 15 driven by the drive module 16 needs to be mixed with cold water to reduce the temperature entering the main heating module 5; when the temperature of the tap water entering the main heating module 5 after preheating through the heat exchange path 3 is lower than the user's required temperature but higher than the pre-temperature (pre-temperature is the user's required temperature minus the maximum temperature rise that the main heating module 5 can provide), the mixing valve core 15 driven by the drive module 16 needs to be mixed with cold water to reduce the temperature entering the main heating module 5 or reduce the real-time heating power of the main heating module 5;

[0085] —Water replenishment mode: Connect the cold water inlet pipe 10 and the water replenishment outlet pipe 14 to inject replenishment water into the hot water storage tank 1; after the water heater is installed, connect the water source and power supply, and the water heater will first detect the high liquid level probe 18 and the low liquid level probe 19. When the liquid level is lower than the low liquid level probe 19, the drive module 16 can drive the mixing valve core 15 to switch to the water replenishment mode to inject or replenish water; when the liquid level reaches the high liquid level probe 18, the drive module 16 can drive the mixing valve core 15 to switch away from the water replenishment mode to stop injecting or replenishing water.

[0086] Furthermore, the hot water storage tank 1 is equipped with a water storage temperature sensor 21, which is located in the upper middle part of the liquid storage space. It is used to detect the temperature of the heat storage medium and feed it back to the control system 7 to control the start and stop of the heat storage heating element 2, so as to ensure that the temperature of the heat storage medium is stable within the set range.

[0087] Furthermore, the control system 7 uses the temperature of the heat storage medium fed back by the water storage temperature sensor 21 to control the integrated mixing unit 4 for water mixing pre-adjustment, thereby improving the stability of the user's required temperature. The integrated mixing unit 4 is also equipped with a mixing temperature sensor 22, which is used to detect the temperature of the mixed water and feed it back to the control system 7 to realize closed-loop control of the water temperature and optimize the response speed of the main heating module 5.

[0088] Furthermore, the control system 7 can be connected to a smart home platform, supporting functions such as remote control via mobile APP, scheduled heating, and energy consumption statistics, thus meeting the development trend of smart homes.

[0089] It should also be noted that in the description of this invention, directional terms such as "center," "lateral," "longitudinal," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. They should not be construed as limiting the specific protection scope of this invention.

[0090] 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. Thus, the use of "first" or "second" to define a feature may explicitly or implicitly include one or more of that feature, and in the description of this invention, "at least" means one or more, unless otherwise explicitly specified.

[0091] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "assembly," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection; they can refer to a direct connection or a connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0092] In the description herein, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer 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.

[0093] In this invention, unless otherwise 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," "below," and "over" 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. "Above," "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.

[0094] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Without departing from the spirit and essence of the invention, those skilled in the art can make various corresponding modifications and variations based on the present invention, but these corresponding changes and variations should all fall within the protection scope of the appended claims.

Claims

1. A combined electric water heater, characterized in that, include: A hot water storage tank has a defined liquid storage space and is filled with a heat storage medium (water). The outer wall of the hot water storage tank is wrapped with a high-performance heat insulation layer, and the hot water storage tank is equipped with a water supply pipe. A heat storage heating element is installed inside the heat storage tank and heats only the heat storage medium; The heat exchange path is completely submerged in the heat storage medium, and a water flow channel is formed inside, allowing the flowing water to exchange heat with the heat storage medium in a non-contact manner. An integrated mixing unit includes a cold water inlet pipe, a cold water outlet pipe, a hot water inlet pipe, a mixing outlet pipe, a makeup water outlet pipe, a mixing valve core, and a drive module. The cold water inlet pipe is used to connect to external cold water; The cold water output pipe is connected to the inlet end of the heat exchange path; The hot water input pipe is connected to the outlet end of the heat exchange path; The mixing outlet pipe outputs the mixed water; The water supply output pipe is connected to the water inlet end of the water supply pipe; The mixing valve core is a multi-channel rotary switching element with multiple throttling orifices and connecting chambers inside. It is connected to the cold water inlet pipe, the hot water inlet pipe, the mixing outlet pipe, and the makeup water outlet pipe, respectively. It can change the connection relationship and flow distribution ratio between the pipes by rotating it. The key feature is that the valve core is designed without a fully closed state, meaning that there is a set of channels connected in any switching position; The drive module, consisting of a stepper motor or a servo motor, is mechanically connected to the rotating handle of the mixing valve core. The main heating module has its inlet end connected to the mixing output pipe and its outlet end connected to the user's water supply pipe. A drain outlet is located at the bottom of the hot water storage tank. A hollow exhaust pipe is integrated inside the drain outlet. The upper end of the exhaust pipe is connected to the gas phase space above the liquid surface of the heat storage medium in the liquid storage space, and the lower end is connected to the atmosphere. The control system is configured to dynamically allocate the heating load of the thermal storage heating element and the rapid heating module according to the water usage parameters and to control the operation of the drive module.

2. The combined electric water heater according to claim 1, characterized in that, The heat storage heating element is located in the bottom area of ​​the hot water storage tank.

3. The combined electric water heater according to claim 1, characterized in that, The heat exchange path is a tubular structure, with its outer wall in direct contact with the heat storage medium and its inner wall in contact with the water flow. The outer wall of the tube located at the heat exchange outlet section is wrapped with heat insulation material.

4. The combined electric water heater according to claim 3, characterized in that, The heat exchange path is made of copper or stainless steel, which have excellent thermal conductivity, and its structure can be designed as a corrugated coil, a serpentine tube, or a multi-pass straight tube.

5. The combined electric water heater according to claim 1, characterized in that, The hot water storage tank is equipped with a high-level probe and a low-level probe to monitor the liquid level of the heat storage medium.

6. The combined electric water heater according to claim 5, characterized in that, The outlet of the water supply pipe is positioned higher than the high liquid level probe.

7. The combined electric water heater according to claim 5, characterized in that, The upper opening of the exhaust pipe is higher than the high liquid level probe.

8. The combined electric water heater according to claim 1, characterized in that, The cold water inlet pipe is equipped with a cold water inlet temperature sensor and a flow sensor.

9. The combined electric water heater according to claim 1, characterized in that, The integrated mixing unit can control the mixing valve core through the drive module to achieve multiple working modes: —Single cold water mode: The mixing valve core connects the cold water inlet pipe and the mixing outlet pipe, cuts off the hot water input, and the water flow does not pass through the heat exchange path, but directly enters the main heating module for heating; —Single hot water mode: The mixing valve core connects the hot water input pipe and the mixing output pipe, and all water flows through the heat exchange path for preheating before entering the main heating module; —Mixed Water Mode: Simultaneously connect the cold water input pipe and the hot water input pipe to the mixed water output pipe, mix the preheated water flow and the original cold water flow according to a set ratio, and adjust the initial water temperature entering the main heating module; —Water replenishment mode: Connect the cold water inlet pipe and the water replenishment outlet pipe to inject replenishment water into the hot water storage tank.

10. The combined electric water heater according to claim 9, characterized in that, When the mixing unit is in single hot water mode, the driving module can further fine-tune the opening of the mixing valve core, thereby reducing the total flow rate entering the main heating module.

11. The combined electric water heater according to claim 1, characterized in that, The main heating module is a fast-heating electric heating element, which has the functions of rapid heating and adjustable power.

12. The combined electric water heater according to claim 1, characterized in that, The hot water storage tank is equipped with a water temperature sensor, which is located in the upper middle part of the liquid storage space. The sensor is used to detect the temperature of the heat storage medium and feed it back to the control system to control the start and stop of the heat storage heating element.

13. The combined electric water heater according to claims 1 and 12, characterized in that, The control system controls the mixing unit to perform water mixing pre-adjustment based on the temperature of the heat storage medium fed back by the water storage temperature sensor.

14. The combined electric water heater according to claim 1, characterized in that, The mixing unit is equipped with a mixing temperature sensor to detect the temperature of the mixed water and feed it back to the control system.

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