Electric water heater

Abstract

The utility model discloses an electric water heater, including water bladder, phase change bladder, water supply line and circulating pipeline, and phase change bladder includes heat exchanger, and circulating pipeline is used to communicate the water bladder and heat exchanger, and one side of water supply line can be communicated with water source, and the switch device is provided on circulating pipeline, and the switch device has first state and second state, when the switch device is in first state, the water in water bladder can circulate and flow between water bladder and heat exchanger, when the switch device is in second state, the water in water bladder can not circulate and flow between water bladder and heat exchanger, and the water in water supply line can flow into heat exchanger, water bladder in proper order, or, can flow into water bladder, heat exchanger in proper order. The electric water heater provided in the application embodiment, through the reasonable and ingenious waterway design, can not only guarantee efficient energy storage, but also can realize stable and comfortable water supply to the water terminal.

Description

Technical Field

[0001] This utility model relates to the field of water heater technology, and in particular to an electric water heater. Background Technology

[0002] Traditional storage-type electric water heaters use water as the heat storage medium, and due to the limitation of water's specific heat capacity, the amount of hot water supplied is limited. Increasing the water volume requires a larger tank, taking up more indoor space. Furthermore, as hot water is released, the water temperature inside the tank gradually decreases, resulting in insufficient hot water temperature and volume to meet user needs. Overall, traditional storage-type electric water heaters, constrained by their size, have limited heat storage capacity and suffer from insufficient hot water supply.

[0003] To improve the heat storage capacity of electric water heaters and increase the hot water supply, phase change water heaters have emerged in the existing technology. These phase change water heaters rely on the physical state transformation of phase change materials to achieve heat storage and release. Before water is used, the phase change material absorbs heat from the heat source for heat storage. While phase change water heaters have heat storage capabilities, they also need to supply hot water to users. Therefore, how to rationally and cleverly design the water circuit is a problem that those skilled in the art need to address.

[0004] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Utility Model Content

[0005] In view of the shortcomings of the existing technology, this utility model provides an electric water heater that, through a reasonable and ingenious water circuit design, can not only ensure efficient energy storage, but also provide a stable and comfortable water supply to the water-using terminal.

[0006] The specific technical solution of this utility model embodiment is as follows:

[0007] An electric water heater includes: a water tank and a phase change tank, the phase change tank having a phase change material for heat storage and release, and the phase change tank further including a heat exchanger for communication with the water tank; the electric water heater further includes a water supply pipe and a circulation pipe, the circulation pipe for connecting the water tank and the heat exchanger, one side of the water supply pipe being able to be connected to a water source, and the other side of the water supply pipe being able to be connected to the heat exchanger and / or the circulation pipe and / or the water tank; a switching device is provided on the circulation pipe, the switching device having a first state and a second state, when... When the switching device is in the first state, the circulation pipeline is open, and the water in the water tank can circulate between the water tank and the heat exchanger; or, the water in the water tank cannot circulate between the water tank and the heat exchanger, and the water in the water supply pipeline can only flow into the water tank. When the switching device is in the second state, the water in the water tank cannot circulate between the water tank and the heat exchanger, and the water in the water supply pipeline can flow into the heat exchanger and the water tank in sequence; or, the water in the water supply pipeline can flow into the water tank and the heat exchanger in sequence.

[0008] In a preferred embodiment, the circulation pipeline includes a first circulation pipeline and a second circulation pipeline. The first circulation pipeline has a first inlet end and a first outlet end, with the first inlet end located in the water tank and the first outlet end located in the phase change tank. The second circulation pipeline has a second inlet end and a second outlet end, with the second inlet end located in the phase change tank and the second outlet end located in the water tank. The switching device is disposed on the first circulation pipeline or the second circulation pipeline.

[0009] In a preferred embodiment, the other side of the water supply pipeline is connected to the first circulation pipeline or the second circulation pipeline at a connection point located downstream of the switching device; or, the other side of the water supply pipeline is connected to the first circulation pipeline or the second circulation pipeline via the switching device.

[0010] In a preferred embodiment, the first water inlet is located at the upper part of the water tank, the first water outlet is located at the upper part of the phase change tank, the second water inlet is located at the lower part of the phase change tank, and the second water outlet is located at the lower part of the water tank.

[0011] In a preferred embodiment, the switching device has at least a first port, a second port, and a third port. The first port is used to connect to the other side of the water supply pipeline. The second port and the third port are connected to the first circulation pipeline or the second circulation pipeline. The second port is located downstream of the third port. When the switching device is in the first state, the second port and the third port are connected. When the switching device is in the second state, the first port and the second port are connected.

[0012] In a preferred embodiment, when the switching device is in the second state, the water in the water tank cannot circulate between the water tank and the heat exchanger; the switching device is located in the first circulation pipeline, and the other side of the water supply pipeline can be connected to the heat exchanger and / or the first circulation pipeline, so that water supplied from the water source can enter the water tank through the water supply pipeline, the heat exchanger, and the second circulation pipeline; or, the switching device is located in the second circulation pipeline, and the other side of the water supply pipeline can be connected to the second circulation pipeline and / or the water tank, so that water supplied from the water source can enter the heat exchanger through the water supply pipeline, the water tank, and the first circulation pipeline.

[0013] In a preferred embodiment, the circulation pipeline is further provided with a pump.

[0014] In a preferred embodiment, the electric water heater further includes a heating element for heating the water in the tank. The electric water heater has a heat storage mode. In the heat storage mode, the switching device is in the first state, and the pump and the heating element start working simultaneously first, and then the pump or the heating element works independently.

[0015] In a preferred embodiment, the electric water heater further includes a heating element for heating the water in the tank. The electric water heater has a heat storage mode. In the heat storage mode, the switching device is in the first state, the heating element starts working first, the pump starts working later, and the heating element continues to work or stops working.

[0016] In a preferred embodiment, the electric water heater further includes a heating element for heating the water in the tank. The electric water heater has a heat storage mode in which the switching device is in the first state, the pump starts working first, the heating element starts working later, and the pump continues to work or stops working.

[0017] In a preferred embodiment, the first water inlet is located at the upper part of the water tank, the first water outlet is located at the lower part of the phase change tank, the second water inlet is located at the upper part of the phase change tank, and the second water outlet is located at the lower part of the water tank. The electric water heater has a heat storage mode and a water use mode. In the heat storage mode, the switch is in the first state, the pump is started, the circulation pipeline is open, and the water in the water tank can circulate between the water tank and the heat exchanger. In the water use mode, the switch is in the first state, the pump is not started, the water in the water tank cannot circulate between the water tank and the heat exchanger, and the water in the water supply pipeline can flow into the water tank only through the circulation pipeline.

[0018] In a preferred embodiment, the electric water heater further includes a water outlet pipe, one end of which is connected to the circulation pipe, and / or the water outlet pipe passes through the water tank.

[0019] In a preferred embodiment, the switching device is disposed on the first circulation pipeline, one end of the water outlet pipe is connected to the first circulation pipeline located upstream of the switching device, or one end of the water outlet pipe is connected to the first circulation pipeline through the switching device, and the water outlet pipe is located outside the water tank.

[0020] In a preferred embodiment, the switching device is disposed on the second circulation pipeline, one end of the water outlet pipe is connected to the second circulation pipeline located upstream of the switching device, or one end of the water outlet pipe is connected to the second circulation pipeline through the switching device, and the water outlet pipe is located outside the water tank.

[0021] In a preferred embodiment, the electric water heater further includes a heating element for heating the water in the tank.

[0022] In a preferred embodiment, the first water inlet is located at the upper part of the water tank, the first water outlet is located at the upper part of the phase change tank, the second water inlet is located at the lower part of the phase change tank, the second water outlet is located at the lower part of the water tank, and the heating component includes a heating rod, with at least one heating rod located at the upper middle or bottom of the water tank.

[0023] In a preferred embodiment, the phase change tank is located above the water tank.

[0024] In a preferred embodiment, a pump is provided on the circulation pipeline, and the circulation pipeline includes a first circulation pipeline and a second circulation pipeline. The first circulation pipeline has a first inlet end and a first outlet end, with the first inlet end located at the phase change tank and the first outlet end located at the water tank. The second circulation pipeline has a second inlet end and a second outlet end, with the second inlet end located at the water tank and the second outlet end located at the phase change tank. The switching device is provided on either the first circulation pipeline or the second circulation pipeline.

[0025] In a preferred embodiment, the other side of the water supply pipeline is connected to the first circulation pipeline or the second circulation pipeline at a connection point located downstream of the switching device; or, the other side of the water supply pipeline is connected to the first circulation pipeline or the second circulation pipeline via the switching device.

[0026] In a preferred embodiment, the first water outlet is located at the lower part of the water tank.

[0027] In a preferred embodiment, the switching device has at least a first port, a second port, and a third port. The first port is used to connect to one side of the water supply pipeline. The second port and the third port are connected to the first circulation pipeline or the second circulation pipeline. The second port is located downstream of the third port. When the switching device is in the first state, the second port and the third port are connected. When the switching device is in the second state, the first port and the second port are connected.

[0028] In a preferred embodiment, when the switching device is in the second state, the water in the water tank cannot circulate between the water tank and the heat exchanger; the switching device is located in the first circulation pipeline, and the water supplied by the water source can enter the heat exchanger through the water supply pipeline, the water tank, and the second circulation pipeline; or, the switching device is located in the second circulation pipeline, and the water supplied by the water source can enter the water tank through the water supply pipeline, the heat exchanger, the first circulation pipeline.

[0029] In a preferred embodiment, the electric water heater further includes a water outlet pipe, one end of which is connected to the circulation pipe or one end of which is connected to the circulation pipe via the switching device, and / or the water outlet pipe passes through the water tank.

[0030] In a preferred embodiment, the switching device is disposed on the first circulation pipeline, one end of the water outlet pipe is connected to the first circulation pipeline located downstream of the switching device, or one end of the water outlet pipe is connected to the first circulation pipeline through the switching device, and the water outlet pipe is located outside the water tank.

[0031] In a preferred embodiment, the switching device is disposed on the second circulation pipeline, one end of the outlet pipe is connected to the second circulation pipeline located downstream of the switching device, or one end of the outlet pipe is connected to the second circulation pipeline through the switching device, and the outlet pipe is located outside the water tank.

[0032] In a preferred embodiment, the phase change tank is located below the water tank.

[0033] The technical solution of this utility model has the following significant beneficial effects:

[0034] In this embodiment, a circulation pipe equipped with a switching device connects the water tank to the heat exchanger. During the heat storage phase, the switching device is in a first state, allowing the heated water in the water tank to flow into the heat exchanger and then back into the water tank, thus achieving circulation. During this circulation process, the heat exchanger, carrying hot water from the water tank, exchanges heat with the phase change material in the phase change tank. This improves the heat exchange efficiency between the heat exchanger and the phase change material, as well as the uniformity of heating the phase change material. It also enhances the heat exchange efficiency during the heat storage phase, shortens the heat storage time, reduces user waiting time, and improves the user experience.

[0035] During the water usage phase, the switching device can be in its second state. Water in the water tank cannot circulate between the water tank and the heat exchanger. Water in the supply pipe can flow between the heat exchanger and the water tank in series (either flowing into the heat exchanger and the water tank sequentially, or vice versa). Overall, by simply switching the state of the switching device, a rapid switch between the water heater's own heat storage and the user's water usage can be achieved. The water circuit design is ingenious, and the pipe structure is simple. Furthermore, since all water supplied from the external source flows through this water tank, the water temperature can be evenly increased, ensuring a relatively stable outlet water temperature and thus providing a stable and comfortable water supply to the user. Especially when the water flows through the heat exchanger before flowing into the water tank, the heat exchanger can preheat the incoming water before it mixes with the water in the tank and is then heated and output. This maximizes the utilization of heat in the water heater, effectively increasing the hot water output.

[0036] For cases where the other side of the water supply pipeline connects to the circulation pipeline, a clever design has been implemented, particularly for the circulation pipeline equipped with a switching device. This design allows for multi-functional reuse at different stages. For example, during the heat storage stage, this circulation pipeline serves as a connecting pipeline between the water tank and the heat exchanger. During the water usage stage, this part of the circulation pipeline can cooperate with the water supply pipeline to supply water to the water tank or heat exchanger. During water supply, switching to the second state via the switching device can prevent cross-flow of water from short-circuiting the heat exchanger, thus meeting the needs of large water usage. Furthermore, during water supply, the switching device can be switched to the first state to short-circuit the heat exchanger, thereby supplying water only to the water tank to meet the needs of small water usage. Through this ingenious design of the water circuit, the functionality of different stages is achieved while effectively reducing manufacturing costs and size, meeting the diverse water usage needs of users.

[0037] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope. Within the spirit and scope of the appended claims, embodiments of the present invention include many changes, modifications, and equivalents. Features described and / or shown for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments. Attached Figure Description

[0038] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, under the guidance of this invention, can select various possible shapes and proportions to implement this invention according to specific circumstances.

[0039] Figure 1 This is one of the structural schematic diagrams of the electric water heater provided in the embodiments of this application;

[0040] Figure 2 This is a second schematic diagram of the structure of the electric water heater provided in the embodiments of this application;

[0041] Figure 3 for Figure 2 A schematic diagram of water flow in the heat storage mode of an electric water heater provided in the embodiments of this application;

[0042] Figure 4 for Figure 2A schematic diagram of water flow in the water usage mode of an electric water heater provided in the embodiments of this application;

[0043] Figure 5 This is the third structural schematic diagram of the electric water heater provided in the embodiments of this application;

[0044] Figure 6 for Figure 5 A schematic diagram of water flow in the water usage mode of an electric water heater provided in the embodiments of this application;

[0045] Figure 7 This is the fourth structural schematic diagram of the electric water heater provided in the embodiments of this application;

[0046] Figure 8 This is the fifth schematic diagram of the electric water heater provided in the embodiments of this application;

[0047] Figure 9 This is the sixth schematic diagram of the electric water heater provided in the embodiments of this application;

[0048] Figure 10 This is the seventh structural schematic diagram of the electric water heater provided in the embodiments of this application;

[0049] Figure 11 This is the eighth schematic diagram of the structure of the electric water heater provided in the embodiments of this application.

[0050] Reference numerals in the figures of this application:

[0051] 1. Phase change cylinder;

[0052] 2. Water tank;

[0053] 3. Heating rod;

[0054] 41. First circulation pipeline;

[0055] 411. First water inlet end;

[0056] 412. First water outlet;

[0057] 42. Second circulation pipeline;

[0058] 421. Second water inlet;

[0059] 422. Second water outlet;

[0060] 5. Heat exchanger;

[0061] 6. Pump;

[0062] 71. First connecting part;

[0063] 72. Second connecting part;

[0064] 81. Water supply pipelines;

[0065] 82. Water outlet pipe;

[0066] 92. Switching device;

[0067] 921, First Port;

[0068] 922, Second Port;

[0069] 923, Third Port;

[0070] X, horizontal direction;

[0071] Y, the height direction. Detailed Implementation

[0072] The technical solution of this utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate this utility model and are not intended to limit the scope of this utility model. After reading this utility model, any modifications of this utility model in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0073] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0074] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0075] This utility model provides an electric water heater with optimized and simplified structure design. Through a reasonable and ingenious water circuit design, it can not only ensure efficient energy storage, but also provide a stable and comfortable water supply to the water-using terminal.

[0076] Please refer to the following for comprehensive information. Figures 1 to 11This application specification provides an electric water heater, which may include: a water tank 2 and a phase change tank 1. The phase change tank 1 has a phase change material for heat storage and release, and the phase change tank 1 also includes a heat exchanger 5 for communication with the water tank 2. The electric water heater also includes a water supply pipe 81 and a circulation pipe. The circulation pipe is used to connect the water tank 2 and the heat exchanger 5. One side of the water supply pipe 81 can be connected to a water source, and the other side of the water supply pipe 81 can be connected to the heat exchanger 5 and / or the circulation pipe and / or the water tank 2. A switching device 92 is provided on the circulation pipe, and the switching device 92 has a first state and a second state. In the first state, the circulation pipeline is open, and the water in the water tank 2 can circulate between the water tank 2 and the heat exchanger 5; or, the water in the water tank 2 cannot circulate between the water tank 2 and the heat exchanger 5, and the water in the water supply pipeline 81 can only flow into the water tank 2. In the second state, the water in the water tank 2 cannot circulate between the water tank 2 and the heat exchanger 5, and the water in the water supply pipeline 81 can flow into the heat exchanger 5 and the water tank 2 in sequence; or, the water in the water supply pipeline 81 can flow into the water tank 2 and the heat exchanger 5 in sequence.

[0077] In this embodiment, the electric water heater may include a phase change tank 1, a water tank 2, a water supply pipe 81, and a circulation pipe, etc.

[0078] The phase change chamber 1 contains a phase change material for heat storage and release. The phase change material's physical state can change, thereby switching between its heat storage and heat release states. The specific material of the phase change material can be inorganic water and salt with added nucleating agents, or it can be in other forms; this application does not impose specific limitations here. In the embodiments of this application, taking a phase change material capable of switching between solid and liquid states as an example, when the phase change material changes from solid to liquid, it is in a heat storage state, absorbing and storing external heat; when the phase change material changes from liquid to solid, it is in a heat release state, releasing the stored heat to the outside.

[0079] The phase change material tank 1 is internally equipped with a heat exchanger 5. Cold water flowing through the heat exchanger 5 can absorb heat from the phase change material, achieving preheating; hot water flowing through the heat exchanger 5 can release heat to the phase change material, achieving heat storage in the phase change material. Specifically, the heat exchanger 5 can be in the form of a heat exchange tube, which can extend entirely along the height direction Y and reciprocate in the left-right direction. Alternatively, the heat exchanger 5 can also take other forms; in this embodiment and accompanying drawings, the heat exchanger 5 is mainly illustrated using a heat exchange tube as an example.

[0080] The water tank 2 has a water storage cavity inside. Generally, the volume of the water tank 2 is at least 10 liters. When the volume of the water tank 2 is 10 liters or more, it can reliably provide the heat required for heat storage to the phase change material in the phase change tank 1, ensuring that the phase change material can store heat efficiently. In addition, when the volume of the water tank 2 is large, water can be supplied to the water terminal at a relatively stable water temperature using the water tank 2. Of course, the use of a small-capacity water tank is not excluded in this application. In some special cases (such as scenarios with limited installation space), the volume of the water tank 2 may be less than 10L.

[0081] In some embodiments, the water tank 2 and the phase change tank 1 can be arranged vertically. For example, the water tank 2 can be located above or below the phase change tank 1. The phase change tank 1 and the water tank 2 can be installed horizontally, with their axes extending along the horizontal direction X. In this case, the axes of the phase change tank 1 and the water tank 2 can be arranged vertically. Of course, in the embodiments of this application, vertical installation of the water tank 2 and the phase change tank 1 is also possible. If the water tank 2 and the phase change tank 1 are installed vertically, their axes extend along the vertical direction Y. In this case, the axes of the phase change tank 1 and the water tank 2 can be arranged horizontally.

[0082] The electric water heater also includes a heating element, which can be used to heat the water in the water tank 2. The heating element can be an electric heating element, such as a heating rod 3. Of course, the heating element can also take other forms; in this embodiment, the heating rod 3 is mainly used as an example. The heating rod can be installed inside the water tank 2, or it can be located outside the water tank 2, such as on the outer surface of the water tank 2, or it can be installed in the circulation pipe, etc. In the embodiments and accompanying drawings of this application, the heating element is mainly illustrated as a heating rod 3 installed in the water tank 2. When the heating element is installed in the water tank 2, it can not only heat the water in the water tank 2, but also heat the water in the circulation pipe, providing heat to the water in the circulation pipe for use in the phase change material.

[0083] The phase change tank 1 may or may not have a heating element. In the case where the phase change material in the phase change tank 1 does not have a heating element, it can absorb heat from the water heated by the heating rod 3 in the water tank 2 when heat storage is required. In this embodiment, the example is provided where the water tank 2 has a heating element and the phase change tank 1 does not.

[0084] The electric water heater also includes a circulation pipe, one function of which is to connect the water tank 2 and the heat exchanger 5. When the heat exchanger 5 needs to exchange heat with the phase change material using the heated water in the water tank 2, i.e., when heat storage of the phase change material is required, the electric water heater can enter the heat storage mode. During the heat storage stage, the heated hot water in the water tank 2 can be flowed into the heat exchanger 5 through the circulation pipe. As the hot water flows through the heat exchanger 5, it releases heat to the phase change material in contact with the heat exchanger 5, thus achieving heat storage of the phase change material.

[0085] The electric water heater may also include a water supply pipe 81, one side of which can be connected to a water source, and the other side of which can be connected to any one of the heat exchanger 5, the circulation pipe, and the water tank 2. The electric water heater has a water usage mode. When the water usage mode is activated, water supplied from an external water source can be supplied to the heat exchanger 5 through the water supply pipe 81. As the water flows through the heat exchanger 5, it absorbs heat from the phase change material in contact with the heat exchanger 5, thereby raising the water temperature and achieving the effect of preheating the incoming water. The preheated water then flows into the water tank 2.

[0086] A switching device 92 is installed on the circulation pipeline, which is mainly used to control the on / off state of the circulation pipeline. Specifically, the state of the switching device 92 can include a first state and a second state. When the switching device 92 is in the first state, it indicates that the water flow in the circulation pipeline where the switching device 92 is located is in a flowable state. At this time, the circulation pipeline is conductive, and the water in the water tank 2 can circulate between the water tank 2 and the heat exchanger 5. For example, in the heat storage stage, when the water in the water tank 2 is heated to hot water, some of the hot water can flow to the heat exchanger 5 through the circulation pipeline, and the water in the heat exchanger 5 can then return to the water tank 2 through the circulation pipeline, thus achieving circulation.

[0087] Alternatively, in another scenario, the water in the water tank 2 cannot circulate between the water tank 2 and the heat exchanger 5, and the water in the water supply pipe 81 can flow directly into the water tank 2. For example, during the water usage phase, this part of the circulation pipe can be used as a connecting pipe between the water supply pipe 81 and the water tank 2. Water supplied from an external water source can flow into the water tank 2 through the water supply pipe 81 and part of the circulation pipe. In this case, the phase change tank 1 can be short-circuited using this part of the circulation pipe, so that the water flowing into the water supply pipe 81 is only supplied into the water tank 2.

[0088] When the switching device 92 is in the second state, a complete water flow circulation cannot be formed between the circulation pipeline, the water tank 2, and the heat exchanger 5, and the water in the water tank 2 cannot circulate between the water tank 2 and the heat exchanger 5. For example, during the water usage phase, the water in the water supply pipeline 81 can flow sequentially into the heat exchanger 5 and the water tank 2, or the water in the water supply pipeline 81 can flow sequentially into the water tank 2 and the heat exchanger 5, and this portion of water can then be supplied to the water user through the outlet pipe 82.

[0089] During the aforementioned water usage phase, when the other side of the water supply pipe 81 is connected to the circulation pipe, this portion of the circulation pipe can also be used as a connecting pipe between the water supply pipe 81 and the water tank 2 or the heat exchanger 5. In specific use, water in the water supply pipe 81 flows sequentially through a portion of the circulation pipe, the heat exchanger 5, and the water tank 2, and then flows out through the outlet pipe 82; alternatively, water in the water supply pipe 81 flows sequentially through a portion of the circulation pipe, the water tank 2, and the heat exchanger 5, and then flows out through the outlet pipe 82. The supplied water flow can follow a predetermined path, preventing short circuits in the circulation pipe and thus avoiding cross-contamination and other problems.

[0090] In this embodiment, the specific form of the switching device 92 can include various types. For example, it can include a switching valve that controls the on / off state of the circulation pipeline it is in, a one-way valve that controls the unidirectional flow of the circulation pipeline it is in, a switching valve that is installed between the circulation pipeline and the water supply pipeline 81, or other forms that can realize water flow control. By setting the switching device 92 on the circulation pipeline, the connection relationship of the water path can be switched, ensuring that the water in the circulation pipeline circulates and stores heat during the heat storage stage, achieving efficient heat storage. During the water use stage, the water supplied by the external water source can flow through the heat exchanger 5, part of the circulation pipeline, and the water tank 2 before being output to the outside, preventing the circulation pipeline from interfering with the water supplied by the external water source during the water use stage, such as short-circuiting the water supplied by the external water source.

[0091] In this embodiment, a heating rod 3 is installed in the water tank 2. When the heating rod 3 is activated, the hot water heated by the heating rod 3 in the water tank 2 is sent to the heat exchanger 5 of the phase change tank 1 through a circulation pipe. At the same time, the cold water in the heat exchanger 5 returns to the water tank 2 through the circulation pipe, thus the water flows between the heat exchanger 5 of the phase change tank 1 and the water tank 2. During the above circulation process, the heat generated by the energized heating rod 3 in the water tank 2 can not only raise the water temperature in the water tank 2, but also raise the water temperature in the heat exchanger 5. The heat of the water in the heat exchanger 5 can be transferred through the shell of the heat exchanger 5 to the phase change material in contact with it, so that the phase change material in the phase change tank 1 absorbs heat and stores energy.

[0092] The method of directly feeding the heated water from the water tank 2 into the heat exchanger 5 to store heat in the phase change material has significant advantages over existing implementation methods:

[0093] For example, compared to directly setting the heating element in the phase change tank 1, it can improve heat exchange efficiency and avoid premature failure of materials near the heating rod 3.

[0094] For heat exchanger 5, it includes: a form with a separate water box, a form with a separate heat exchange tube, and a form with a combination of water box and heat exchange tube.

[0095] For heat exchanger 5 as a separate heat exchange tube, compared to setting a heating element in a heat exchanger (e.g., a water box) inside the phase change tank 1, since the volume of the water box is limited, usually within 3L, during the heat storage stage, the heating element with a large heating power is in a state of frequent start-stop when heating the limited volume of water. The duration of each start-up of the heating element is limited, so the heat generated by a single heating is small, which leads to an increase in the heat storage time and poor heat exchange efficiency.

[0096] For example, compared to electric water heaters that have a water box in the phase change tank 1 connected to the water tank 2 via a circulation pipe, this application directly eliminates the water box structure, effectively reducing manufacturing costs and complexity. The number of water boxes is easily limited by installation space and cost, making it impossible to distribute them evenly within the phase change material. In this application, heat exchanger 5 is used directly for heat exchange with the phase change material. Since heat exchanger 5 can be evenly distributed within the phase change material of the phase change tank 1, it further improves the heat exchange efficiency and heating uniformity between the heat exchanger and the phase change material. Furthermore, compared to the method of setting a water box in the phase change tank 1, the inner surface of the water box is prone to scaling during use, thus affecting the heat exchange effect. In this application, heat exchanger 5 is directly used as a carrier for circulating hot water to store heat in the phase change material. Because the hot water has a certain flow velocity when flowing in heat exchanger 5, it can effectively flush the pipe wall, thus effectively slowing down the scaling rate on the pipe wall of heat exchanger 5, thereby ensuring better heat exchange performance.

[0097] Furthermore, by installing a switch device 92 in the circulation pipeline, and combining the different working states of the switch device 92, water circuits with different flow paths can be formed inside the electric water heater, thereby meeting the connection requirements of different water circuits during the heat storage stage and the water use stage. For example, during the heat storage stage, the phase change material in the phase change tank 1 can be stored by establishing a connected circulation pipeline; during the water use stage, part of the circulation pipeline can be shielded as needed to prevent cross-contamination and realize the series water supply of the heat exchanger 5 and the water tank 2; or, according to the user's needs, part of the circulation pipeline can be connected to realize the function of water tank 2 supplying water independently.

[0098] In summary, in this embodiment, a circulation pipe equipped with a switching device 92 connects the water tank 2 to the heat exchanger 5. During the heat storage phase, the switching device 92 is in its first state, the circulation pipe is open, and the heated water in the water tank 2 flows into the heat exchanger 5 through the circulation pipe, and then returns to the water tank 2, thus achieving circulation. During the above-mentioned circulation process, the heat exchanger 5, which carries the hot water from the water tank 2, exchanges heat with the phase change material in the phase change tank 1, which can improve the heat exchange efficiency between the heat exchanger 5 and the phase change material and the uniformity of heating the phase change material; it can also improve the heat exchange efficiency during the heat storage phase, shorten the heat storage time, shorten the user's waiting time, and improve the user experience.

[0099] During the water usage phase, the switch device 92 can be in the second state, where the water in the water tank 2 cannot circulate between the water tank 2 and the heat exchanger 5. Water in the water supply pipe 81 can flow between the heat exchanger 5 and the water tank 2 in series (either flowing into the heat exchanger 5 and the water tank 2 sequentially, or flowing into the water tank 2 and the heat exchanger 5 sequentially). Overall, by simply switching the state of the switch device 92, a rapid switch between the water heater's own heat storage and the user's water usage can be achieved. The water circuit design is ingenious, and the pipe structure is simple. Furthermore, since all water supplied from the external water source flows through the water tank 2, the water temperature of the incoming water can be evenly increased, ensuring a relatively stable outlet water temperature and thus providing a stable and comfortable water supply to the user. Especially when the water flows through the heat exchanger 5 first and then through the water tank 2, the heat exchanger 5 can preheat the incoming water before it flows into the water tank 2, mixes with the water in the tank 2, and is then heated and output. This maximizes the utilization of heat in the electric water heater, effectively increasing the hot water output.

[0100] Regarding the connection of the other side of the water supply pipe 81 to the circulation pipe, a clever design was implemented for the circulation pipe equipped with the switching device 92. This design allows for multi-functional reuse at different stages. For example, during the heat storage stage, this circulation pipe serves as a connecting pipe between the water tank 2 and the heat exchanger 5. During the water usage stage, this part of the circulation pipe can cooperate with the water supply pipe 81 to supply water to either the water tank 2 or the heat exchanger 5. When supplying water, switching the switching device 92 to the second state prevents cross-flow of water from short-circuiting the heat exchanger 5, thus meeting the demand for large water volumes. Furthermore, during water supply, the switching device 92 can be switched to the first state to short-circuit the heat exchanger 5, allowing only the water tank 2 to receive water, meeting the demand for small water volumes. Through this ingenious design of the water circuit, the functionality of different stages is achieved while effectively reducing manufacturing costs and size, meeting the diverse water usage needs of users.

[0101] In some embodiments of this application, the phase change tank 1 may be located above the water tank 2.

[0102] In this embodiment, the phase change tank 1 and the water tank 2 are connected through a circulation pipeline. During the start-up process of the heating rod 3, no additional power source is required, and the water can circulate naturally in the circulation pipeline. This simplifies the system, reduces energy consumption, effectively controls the overall cost, and does not generate noise that disturbs the user.

[0103] In order to allow the heated hot water in water tank 2 to flow into phase change tank 1 by natural convection, a circulation pipeline is provided between the heat exchanger 5 of phase change tank 1 and water tank 2.

[0104] Specifically, the circulation pipeline may include: a first circulation pipeline 41 and a second circulation pipeline 42. The first circulation pipeline 41 has a first water inlet 411 and a first water outlet 412. The first water inlet 411 is located in the water tank 2, and the first water outlet 412 is located in the phase change tank 1. The second circulation pipeline 42 has a second water inlet 421 and a second water outlet 422. The second water inlet 421 is located in the phase change tank 1, and the second water outlet 422 is located in the water tank 2. The switching device 92 is disposed on the first circulation pipeline 41 or the second circulation pipeline 42.

[0105] The water tank 2 is connected to the heat exchanger 5 of the phase change tank 1 via the first circulation pipe 41 and the second circulation pipe 42. When the heating rod 3 is working, the hot water in the water tank 2 heated by the heating rod 3 expands due to heat. The less dense hot water flows upward and enters the heat exchanger 5 through the first circulation pipe 41. The less dense water in the heat exchanger 5, which has a lower temperature, returns to the water tank 2 through the second circulation pipe 42. In this way, the water flow circulates between the heat exchanger 5 of the phase change tank 1 and the water tank 2.

[0106] During the aforementioned circulation process, the heat generated by energizing the heating rod 3 can raise the water temperature in the water tank 2, and also raise the water temperature in the heat exchanger 5. The heat from the water in the heat exchanger 5 can be transferred through its shell to the phase change material in contact with it, allowing the phase change material to absorb heat and store energy. To ensure that, during the heat storage phase, the hot water flowing from the water tank 2 into the phase change tank 1 and into the heat exchanger 5 can return to the water tank 2 more efficiently along the circulation pipe without additional driving force, at least part of the heat exchanger 5 is arranged from top to bottom along the water flow direction in the height direction Y of the phase change tank 1. If the water flowing from the water tank 2 into the phase change tank 1 flows entirely from bottom to top along the height direction Y, due to the combined effects of internal pipe resistance in the heat exchanger 5, gravity, and a drop in water temperature, the hot water in the water tank 2 may flow upwards for a certain distance before its temperature drops and it stops flowing, making it difficult to return to the water tank 2 without external driving force.

[0107] Of course, in other embodiments of this application, it is not excluded that a driving device, such as a pump 6, is provided in the circulation pipeline to provide driving force for the water flow in the circulation water circuit.

[0108] In one embodiment, the number of heating rods 3 is one, and the heating rod 3 is disposed in the middle, upper or lower part of the water tank 2; or, the heating rod 3 includes a first heating rod and a second heating rod, the first heating rod is disposed in the lower part of the water tank 2, and the second heating rod is disposed in the middle or upper part of the water tank 2.

[0109] In one specific embodiment, the number of heating rods 3 can be one. When the number of heating rods 3 is one, the heating rod 3 is located in the middle, upper part or bottom of the water tank 2.

[0110] When the heating rod 3 is located in the middle or upper part of the water tank 2, after the heating rod 3 is activated, it can efficiently concentrate the heat from the energized heating rod 3 to heat the water in the upper part of the water tank 2 (i.e., the water near and above the heating rod 3), allowing this part of the water to quickly reach a higher temperature. Thus, during the heat storage stage, after the water temperature in the upper part of the heating rod 3 is rapidly increased, as the water temperature rises and the density decreases, the hot water can enter the heat exchanger 5 of the phase change tank 1 through the first circulation pipe 41 via natural convection. After exchanging heat with the phase change material in the phase change tank 1, it returns to the water tank 2 through the second circulation pipe 42, thus forming a cycle. Furthermore, when the heating rod 3 preferentially heats the water in the upper part of the water tank 2, a large temperature difference is formed between the upper part of the water tank 2 and the phase change tank 1. This facilitates efficient heat exchange from the upper part of the water tank 2 to the phase change material in the lower part of the phase change tank 1, thereby significantly improving heat exchange efficiency and shortening the heat exchange time.

[0111] In particular, the longitudinal section of the water tank 2 is circular, while the longitudinal section of the phase change tank 1 can be saddle-shaped or inverted U-shaped. The heat exchanger 5 and the inner surface of the lower outer wall of the phase change tank 1 have a predetermined distance. Specifically, when the lower part of the phase change tank 1 is designed to contact the upper part of the water tank 2, the shape of the lower part of the phase change tank 1 is irregular. At the lower part of the phase change tank 1, it is difficult for the heat exchanger 5 to be fully distributed. The lower end of the heat exchanger 5 is at a predetermined distance from the bottom wall of the water tank 2. Therefore, the heat transfer of the phase change material at the lower part of the phase change tank 1 is poor, and even a heat transfer dead zone may occur.

[0112] When the heating rod 3 is placed in the middle or upper part of the water tank 2, the heat generated by the heating rod 3 after it is turned on can reach the lower part of the phase change tank 1 quickly and efficiently with a shorter heat transfer path, so as to fully store the heat of the phase change material in the lower part of the phase change tank 1, thereby making the heat storage of the phase change material in the entire phase change tank 1 uniform, which is beneficial to improving the hot water output of the electric water heater.

[0113] In addition, during the water usage phase, when the heating rod 3 is positioned high (located in the middle or upper part of the water tank 2), the heating rod 3 can be used to concentrate the heating of the water above the middle of the water tank 2, which is beneficial to improve the heat replenishment effect and thus increase the hot water output of the electric water heater.

[0114] Overall, by placing the heating rod 3 in the middle or upper part of the water tank 2 at a relatively high position, efficient heat transfer can be achieved during the heat storage stage, ensuring that the phase change material in the lower part of the phase change tank 1 stores heat evenly and sufficiently, which is beneficial to increasing the hot water output of the electric water heater. When using a small amount of water, the heating rod 3 at this higher position can be used to heat the water in the upper part of the water tank 2 in a concentrated manner, so as to achieve rapid hot water output. Alternatively, in the later stages of using a large amount of water, the heating rod 3 at this higher position can be used to heat the water in the upper part of the water tank 2 in a concentrated manner, further increasing the hot water output of the electric water heater.

[0115] In one specific embodiment, only one heating rod 3 can be provided in the upper middle part of the water tank 2. Providing only one heating rod 3, compared to providing two heating rods 3, can further reduce the number of parts and lower costs. In addition, it can also reduce the number of openings on the water tank 2 and improve the pressure-bearing capacity of the water tank 2.

[0116] In another embodiment, the number of heating rods 3 can be two. The heating rods 3 may include a first heating rod and a second heating rod, with the first heating rod disposed at the lower part of the water tank 2 and the second heating rod disposed at the middle, upper part, or bottom of the water tank 2.

[0117] In this embodiment, the main difference from the above embodiment is that the number of heating rods 3 can include two. In addition to one heating rod 3 (the second heating rod) located in the middle or upper part of the water tank 2, another heating rod 3 (the first heating rod) is located in the lower part of the water tank 2. During the heat storage stage, only the second heating rod can be activated. When the heating power of the second heating rod is the same as or similar to the heating power of the first heating rod 3, the technical effect of using only one heating rod 3 can be achieved.

[0118] For the embodiment with two electric heating rods 3, different operating modes can be provided to the user based on the activation conditions of the electric heating rods 3. Operating mode one involves activating only the second heating rod during the heat storage phase, as described above. Operating mode two involves activating both the first and second heating rods during the heat storage phase and during the process of raising the water temperature in the water tank 2. This helps to uniformly raise the water temperature in the water tank 2 to the predetermined temperature, thereby shortening the user's waiting time for water. For example, when the user's most urgent need is to shorten the waiting time between two water usage intervals, operating mode two can be used without considering energy consumption. The heating power of the first and second heating rods can be the same or different; this application does not specify specific numerical values.

[0119] In some embodiments, the number of heating rods 3 can be one, two, or more. At least one heating rod 3 is located at the bottom of the water tank 2, allowing the temperature of the water in the entire tank to be raised to a higher temperature before circulation or dispensing. Especially in scenarios where the water tank 2 itself has a small volume, having heating rods 3 at the bottom of the water tank 2 ensures that sufficient heat is provided to the phase change material during heat storage, and that a sufficient amount of hot water is provided to the user during water use.

[0120] In some embodiments, the other side of the water supply pipe 81 is connected to the first circulation pipe 41 or the second circulation pipe 42 at a connection point located downstream of the switching device 92; or, the other side of the water supply pipe 81 is connected to the first circulation pipe 41 or the second circulation pipe 42 via the switching device 92.

[0121] In this embodiment, the other side of the water supply pipe 81 can be connected to any one of the heat exchanger 5, the circulation pipe, or the water tank 2. When the water supply pipe 81 is connected to the circulation pipe, it is possible to avoid setting up an opening for connecting the water supply pipe 81 separately on the water tank 2 or in the heat exchanger 5, which helps to ensure the overall reliability of the water tank 2 and the heat exchanger 5, reduce manufacturing difficulty and cost, and improve the integration of the pipeline.

[0122] In this embodiment, the connection point between the other side of the water supply pipe 81 and the circulation pipe can be located downstream of the switching device 92. The relative upstream and downstream positions are illustrated primarily based on the flow direction of the circulating water. For example, the location where hot water flows out of the water tank 2 is the relatively upstream position. Taking the switching device 92 as an example where it is located on the first circulation pipe 41, after the hot water flows out of the water tank 2, it can sequentially return to the water tank 2 through the first circulation pipe 41, the heat exchanger 5, and the second circulation pipe 42.

[0123] When the connection is located downstream of the switch device 92, during the water usage phase, the switch device 92 can be set to the second state to isolate the water supplied by the first circulation pipe 41 below the switch device 92 from the water supplied by the water supply pipe 81, preventing the cold water supplied by the water supply pipe 81 from flowing directly into the water tank 2 through the first circulation pipe 41, that is, short-circuiting the heat exchanger 5, so that the supplied cold water cannot be preheated by the heat exchanger 5.

[0124] The other side of the water supply pipe 81 can be connected to the circulation pipe via a first connecting part 71, for example, the first connecting part 71 can be in the form of a tee. The switching device 92 can be in the form of a switch valve, a check valve, or a switching valve. Of course, in other embodiments, the switching device 92 can also be integrated into the first connecting part 71, in which case the other side of the water supply pipe 81 can be connected to the first circulation pipe 41 or the second circulation pipe 42 via the switching device 92.

[0125] In one embodiment, the first water inlet 411 is located at the upper part of the water tank 2, the first water outlet 412 is located at the upper part of the phase change tank 1, the second water inlet 421 is located at the lower part of the phase change tank 1, and the second water outlet 422 is located at the lower part of the water tank 2.

[0126] When the first inlet end 411 of the first circulation pipe 41 is located at the upper part of the water tank 2, the water that is preferentially heated at the upper part of the water tank 2 can enter the heat exchanger 5 at a faster speed and with a shorter path, thereby achieving heat storage of the phase change material. This allows the phase change material in the phase change tank 1 to complete the heat storage process as soon as possible and shorten the heat storage time. In addition, since the lower temperature water flowing out of the heat exchanger 5 flows into the lower part of the water tank 2 through the second outlet end 422, this setting can prevent the lower temperature water from disturbing the decreasing water temperature of the water tank 2 from top to bottom in the early stage of heat storage. It also helps to ensure that the higher temperature water can stably pass through the first circulation pipe 41 into the heat exchanger 5 at the upper part, thereby achieving heat storage of the phase change material in the phase change tank 1.

[0127] The first water outlet 412 is located at the upper part of the phase change tank 1, and the second water inlet 421 is located at the lower part of the phase change tank 1. This facilitates the hot water flowing into the heat exchanger 5 through the first circulation pipe 41 to flow smoothly inside the heat exchanger 5 under the action of gravity. In other words, even without an external drive, the water flowing out of the water tank 2 can reliably flow through the heat exchanger 5 to achieve circulation.

[0128] Of course, in the embodiments of this application, it is not excluded that the positions of the first water inlet 411, the first water outlet 412, the second water inlet 421 and the second water outlet 422 may be changed according to actual design requirements in other embodiments.

[0129] The following examples illustrate different forms of the switching device 92.

[0130] like Figure 1 As shown, in the first embodiment, the switching device 92 can be a one-way valve. This one-way valve can be installed in the first circulation pipe 41, and it unidirectionally guides the flow of water along the circulation pipe. During the heat storage stage, the water heated in the upper part of the water tank 2 can flow into the heat exchanger 5 through the first circulation pipe 41, flow downwards through the heat exchanger 5, and then return to the lower part of the water tank 2 through the second circulation pipe 42. During the water usage stage, the one-way valve prevents water supplied from an external water source from flowing into the upper part of the water tank 2 through the first inlet 411 of the first circulation pipe 41, thereby ensuring the stability of the water temperature in the upper part of the water tank 2, ensuring that water meeting the user's outlet temperature requirements is provided, and guaranteeing the user's user experience.

[0131] like Figure 2 As shown, in the second type of embodiment, the switching device 92 can be in the form of a switching valve. For example, the switching device 92 can specifically be in the form of a solenoid valve with switching function.

[0132] During the heat storage phase, the switching device 92 can be in the first state, enabling the circulation pipeline to be open. For example... Figure 3 As shown, the water heated in the upper part of the water tank 2 can flow into the heat exchanger 5 through the first circulation pipe 41, and after flowing from top to bottom through the heat exchanger 5, it returns to the lower part of the water tank 2 through the second circulation pipe 42, thereby achieving efficient heat storage of the phase change material in the phase change tank 1.

[0133] During the water usage phase, when the switching device 92 is in the second state, the water in the water tank 2 cannot circulate between the water tank 2 and the heat exchanger 5, thereby placing the circulation pipeline in a non-conductive state.

[0134] In this embodiment, during the heat storage stage, a circulation pipeline is used to introduce heated water from the water tank 2 into the heat exchanger 5 of the phase change tank 1, thereby achieving water circulation between the water tank 2 and the heat exchanger 5 and storing heat for the phase change material in the phase change tank 1. During the water use stage, the circulation pipeline is used to allow water that has exchanged heat with the phase change material in the heat exchanger 5 of the phase change tank 1 to flow into the water tank 2. During the operation of the electric water heater, the circulation pipeline is reused for multiple functions, which can effectively reduce the number and length of pipelines, reduce the risk of leakage, and also reduce manufacturing and maintenance costs.

[0135] like Figure 4 As shown, when the switch device 92 is installed in the first circulation pipeline 41, the other side of the water supply pipeline 81 can be connected to the heat exchanger 5 and / or the first circulation pipeline 41, and the water supplied by the water source can enter the water tank 2 through the water supply pipeline 81, the heat exchanger 5, and the second circulation pipeline 42.

[0136] Taking the other side of the water supply pipeline 81 as connected to the first circulation pipeline 41 as an example, the water supplied by the water source can enter the water tank 2 after passing through the water supply pipeline 81, part of the first circulation pipeline 41, the heat exchanger 5, and the second circulation pipeline 42.

[0137] During this water usage phase, the first circulation pipe 41 and all of the second circulation pipe 42 are reused. Furthermore, since the supplied water first passes through the heat exchanger 5 before entering the water tank 2, the phase change material in the phase change tank 1 can exchange heat with the cold water flowing through the heat exchanger 5, thereby preheating the cold water supplied from the external water source. This increases the total hot water supply of the electric water heater, meeting the user's demand for large water usage.

[0138] Furthermore, the electric water heater may also include a water outlet pipe 82, one end of which is connected to the circulation pipe, and / or the water outlet pipe 82 passes through the water tank 2.

[0139] In this embodiment, one end of the water outlet pipe 82 can be connected to the circulation pipeline, for example, as shown in the example. Figure 3 As shown, one end of the water outlet pipe 82 can be connected to the first circulation pipe 41. When one end of the water outlet pipe 82 is connected to the first circulation pipe 41, it is located upstream of the switching device 92. Specifically, one end of the water outlet pipe 82 can be connected to the first circulation pipe 41 via a second connecting part 72. This second connecting part 72 can be a T-junction, but its form is not limited to the example described above. The second connecting part 72 can be located upstream of the switching device 92 along the direction of circulating water flow. Furthermore, when the second connecting part 72 is integrated with the switching device 92, one end of the water outlet pipe 82 can be connected to the circulation pipe via the switching device 92.

[0140] During the water usage phase, the water supplied by the water source can enter the water tank 2 after passing through the water supply pipeline 81, part of the first circulation pipeline 41, the heat exchanger 5, and the second circulation pipeline 42, and then be supplied to the water terminal through part of the first circulation pipeline 41 and the water outlet pipe 82.

[0141] Since the first inlet end 411 of the first circulation pipe 41 is located at the upper part of the water tank 2, this part of the first circulation pipe 41 functions as the outlet pipe 82, allowing hot water at a higher temperature at the upper part of the water tank 2 to be discharged from the water tank 2. In addition, during this water usage phase, the portion of the first circulation pipe 41 upstream of the second connection 72 (used as the inlet pipe of the water supply pipe 81) and the portion of the first circulation pipe 41 downstream of the first connection 71 (used as the outlet pipe of the outlet pipe 82) are fully reused, further improving the utilization rate of the circulation pipe.

[0142] In this embodiment, the water outlet pipe 82, which is connected to the circulation pipeline at one end, is located entirely outside the water tank 2. This arrangement eliminates the need to create a separate opening in the water tank 2 for installing the water outlet pipe 82, thereby improving the reliability of the water tank 2 during use, reducing the risk of leakage, and lowering manufacturing costs.

[0143] In other embodiments, it is also possible that the water tank 2 is equipped with a water outlet pipe 82. For example, when upgrading an existing water tank 2, the existing water outlet pipe 82 can be retained. Alternatively, in some high-water-volume scenarios, the water outlet pipe 82 can also be used to dispense water simultaneously.

[0144] like Figure 5 As shown, the switch device 92 can be installed in the second circulation pipeline 42, and the other side of the water supply pipeline 81 can be connected to the second circulation pipeline 42 and / or the water tank 2. The water supplied by the water source can enter the heat exchanger 5 through the water supply pipeline 81, the water tank 2, and the first circulation pipeline 41.

[0145] like Figure 6 As shown, taking the other end of the water supply pipeline 81 connected to the second circulation pipeline 42 as an example, the water supplied by the water source can pass through the water supply pipeline 81, part of the second circulation pipeline 42, the water tank 2, and the first circulation pipeline 41, and enter the heat exchanger 5.

[0146] When the switch device 92 is installed on the second circulation pipe 42, one end of the outlet pipe 82 is connected to the second circulation pipe 42 located upstream of the switch device 92, or one end of the outlet pipe 82 is connected to the second circulation pipe 42 through the switch device 92. The outlet pipe 82 is located outside the water tank 2.

[0147] Specifically, the water supply pipe 81 connects to the second circulation pipe 42 at the first connection point 71, and the other end of the outlet pipe 82 connects to the second circulation pipe 42 at the second connection point 72. The first connection point 71 can be located downstream of the second connection point 72. The first connection point 71 and the second connection point 72 can be in the form of a tee structure, or integrated with the switch device 92; however, this application does not impose any specific limitations. When the second connection point 72 is integrated with the switch device 92, one end of the outlet pipe 82 can be connected to the circulation pipe through the switch device 92.

[0148] When the electric water heater enters the water use mode, that is, when it is in use, the water supplied by the external water source enters the water tank 2 through the water supply pipe 81 and part of the second circulation pipe 42, and then enters the heat exchanger 5 through the first circulation pipe 41. The water flowing out of the heat exchanger 5 flows out through part of the second circulation pipe 42 and then flows out from the outlet pipe 82 to supply the water terminal.

[0149] During this water usage phase, the portion of the second circulation pipeline 42 downstream of the first connection 71 (used as the inlet pipeline of the water supply pipeline 81) and the portion of the pipeline upstream of the second connection 72 (used as the outlet pipeline of the water outlet 82) are fully reused, further improving the utilization rate of the circulation pipeline.

[0150] In this embodiment, the water outlet pipe 82, which is connected to the circulation pipeline at one end, is located entirely outside the water tank 2. This arrangement eliminates the need to create a separate opening in the water tank 2 for installing the water outlet pipe 82, thereby improving the reliability of the water tank 2 during use, reducing the risk of leakage, and lowering manufacturing costs.

[0151] like Figure 7 As shown, in the third type of embodiment, the switching device 92 can be a multi-way valve, for example, a switching valve.

[0152] The switching device 92 has at least a first port 921, a second port 922, and a third port 923. The first port 921 is used to connect to the other side of the water supply pipe 81. The second port 922 and the third port 923 are connected to the first circulation pipe 41 or the second circulation pipe 42. The second port 922 is located downstream of the third port 923. When the switching device 92 is in the first state, the second port 922 and the third port 923 are connected. When the switching device 92 is in the second state, the first port 921 and the second port 922 are connected.

[0153] In this embodiment, the switch device 92 can be located at the position where the water supply pipe 81 is connected to the circulation pipe. Specifically, the switch device 92 can include multiple ports, wherein the first port 921 can be used as a water inlet port, and the second port 922 and the third port 923 can be connected in the circulation pipe.

[0154] by Figure 7 Taking the switching device 92 installed in the first circulation pipe 41 as an example, during the heat storage stage, when the switching device 92 is in the first state, the second port 922 and the third port 923 are connected, and the heated water in the water tank 2 returns to the water tank 2 through the first circulation pipe 41, the heat exchanger 5, and the second circulation pipe 42. During the water use stage, when the switching device 92 is in the second state, the first port 921 and the second port 922 are connected, and water supplied from an external water source enters the water tank 2 through the water supply pipe 81, part of the first circulation pipe 41, the heat exchanger 5, and the second circulation pipe 42. Subsequently, the water in the water tank 2 can flow out of the water tank 2 through part of the first circulation pipe 41 and the outlet pipe 82.

[0155] During the water usage phase, the externally supplied water flows sequentially through heat exchanger 5 and water tank 2. The two are connected in series, which can provide the user with the maximum hot water supply, thereby meeting the user's demand for large water consumption.

[0156] like Figure 8 As shown, in some embodiments, the circulation pipeline is also equipped with a pump 6.

[0157] In this embodiment, a drive device (e.g., pump 6) can be installed in the circulation pipeline to provide driving force for the water flow in the circulation water path.

[0158] In one embodiment, the first water inlet 411 is located at the upper part of the water tank 2, the first water outlet 412 is located at the lower part of the phase change tank 1, the second water inlet 421 is located at the upper part of the phase change tank 1, and the second water outlet 422 is located at the lower part of the water tank 2. The electric water heater has a heat storage mode and a water use mode. In the heat storage mode, the switch device 92 is in the first state, the pump 6 is started, the circulation pipeline is open, and the water in the water tank 2 can circulate between the water tank 2 and the heat exchanger 5. In the water use mode, the switch device 92 is in the first state, the pump 6 is not started, the water in the water tank 2 cannot circulate between the water tank 2 and the heat exchanger 5, and the water in the water supply pipeline 81 can flow into the water tank 2 only through the circulation pipeline.

[0159] In this embodiment, the circulation pipeline includes a first circulation pipeline 41 and a second circulation pipeline 42. The specific configuration of each water inlet and outlet end of the first circulation pipeline 41 and the second circulation pipeline 42 can be referred to the specific description of the above embodiment, and will not be repeated here.

[0160] Taking the pump 6 installed in the first circulation pipe 41 as an example, the pump 6 can be located upstream of the switching device 92. The electric water heater can include multiple water usage modes. For example, in one water usage mode, the heat exchanger 5 and the water tank 2 are connected in series for water supply; the specific connection relationship can be referred to the detailed description of the above embodiments of this application, which will not be repeated here. In another water usage mode, only the water tank 2 can be used for water supply. When only the water tank 2 is used for water supply, the switching device 92 is in the first state, the pump 6 is not started, the water in the water tank 2 cannot circulate between the water tank 2 and the heat exchanger 5, and the water in the water supply pipe 81 can flow into the water tank 2 after passing through part of the circulation pipe.

[0161] When the water heater is in heat storage mode, the switch device 92 is in the first state, and the pump 6 can be started when needed. The water in the water tank 2 can circulate between the water tank 2 and the heat exchanger 5 at a predetermined flow rate.

[0162] In this embodiment, the electric water heater can be equipped with a controller, which can be in the form of an electronic control board or a central controller. The pump 6 and the heating element (e.g., heating rod 3) located in the water tank 2 can be electrically connected to the controller. The controller can further optimize and improve the heat storage mode by controlling the working state of the pump 6 and the heating rod 3.

[0163] In one embodiment, a heating rod 3 is provided in the water tank 2, and the electric water heater has a heat storage mode. In the heat storage mode, the switch device 92 is in the first state, the heating rod 3 is started first, the pump 6 is started and then the heating rod 3 continues to work or stops working.

[0164] For example, after the heating rod 3 has been running for a predetermined period of time, the temperature in the water tank 2 reaches a preset temperature, and the pump 6 starts again. At this time, the pump 6 and the heating rod 3 can work simultaneously, or the heating rod 3 can stop heating after the pump 6 starts working.

[0165] And / or, in one embodiment, a heating rod 3 is provided in the water tank 2, and the electric water heater has a heat storage mode. In the heat storage mode, the switching device 92 is in the first state, the pump 6 and the heating rod 3 are started simultaneously, and then the pump 6 or the heating rod 3 works independently.

[0166] For example, after the pump 6 and the heating rod 3 have been started and operated for a predetermined period of time, the pump 6 or the heating rod 3 may operate independently.

[0167] And / or, in one embodiment, a heating rod 3 is provided in the water tank 2, the electric water heater has a heat storage mode, in which the switching device 92 is in the first state, the pump 6 starts working first, the heating rod 3 starts working later, and the pump 6 continues to work or stops working.

[0168] For example, the heating rod 3 may start after the pump 6 has been running for a predetermined period of time, and the heating rod 3 may work simultaneously with the pump 6; or the pump 6 may stop working after the heating rod 3 has started working.

[0169] The following example illustrates the combination of the working states of the pump 6 and the heating rod 3 using a specific application scenario.

[0170] When the electric water heater is in heat storage mode, the switch device 92 is in the first state, and the circulation pipeline itself is in a conductive state.

[0171] If the water temperature in water tank 2 is still relatively low, heating rod 3 can be used to raise the water temperature in water tank 2, and pump 6 will not work temporarily. When the water temperature in water tank 2 reaches the predetermined temperature, due to thermal expansion and contraction, the water in water tank 2 can flow into heat exchanger 5 through natural convection for circulation.

[0172] When the water in the water tank 2 can enter the heat exchanger 5 through natural convection, the temperature of the phase change material is generally low in the initial stage of heat storage, and the temperature drop of the water flowing through the heat exchanger 5 is large. At this time, the water pump 6 can be started and the heating rod 3 can be kept working. The water pump 6 drives the circulation to achieve forced convection, ensuring that the phase change material in the phase change tank 1 can reliably and efficiently obtain heat storage.

[0173] In the later stage of heat storage, when the temperature of the phase change material is already high and the temperature drop of the water flowing through the heat exchanger 5 is small, the heating rod 3 can be turned off, and the water pump 6 can be kept running for a period of time before being stopped.

[0174] Alternatively, in another scenario, if the water temperature in tank 2 is relatively high, pump 6 can be started directly to drive circulation and achieve forced convection. After the water temperature in tank 2 drops to a certain level, heating rod 3 can then be started for heating. In this case, pump 6 and heating rod 3 can work simultaneously. Of course, pump 6 can also be temporarily stopped or cease operation after heating rod 3 is started.

[0175] Overall, the working states of the heating rod 3 and the pump 6 can be combined and arranged after comprehensive judgment based on the water temperature in the water tank 2 and the flow rate of the fluid in the circulation pipeline. This application does not make a unique limitation here.

[0176] Please refer to the following: Figures 9 to 11 In other embodiments of this application, the relative positions between the phase change tank 1 and the water tank 2 can be in other forms. For example, the phase change tank 1 can be located below the water tank 2.

[0177] In the embodiment where the phase change tank 1 is located below the water tank 2, a pump 6 is provided on the circulation pipeline. The circulation pipeline includes a first circulation pipeline 41 and a second circulation pipeline 42. The first circulation pipeline 41 has a first water inlet 411 and a first water outlet 412. The first water inlet 411 is located on the phase change tank 1, and the first water outlet 412 is located on the water tank 2. The second circulation pipeline 42 has a second water inlet 421 and a second water outlet 422. The second water inlet 421 is located on the water tank 2, and the second water outlet 422 is located on the phase change tank 1. The switching device 92 is provided on the first circulation pipeline 41 or the second circulation pipeline 42.

[0178] In addition, the electric water heater may also include a water outlet pipe 82, one end of which is connected to the circulation pipe or one end of which is connected to the circulation pipe through the switch device 92, and / or the water outlet pipe 82 passes through the water tank 2.

[0179] In one embodiment, the other side of the water supply pipe 81 is connected to the first circulation pipe 41 or the second circulation pipe 42 at a connection point, the connection point being located downstream of the switching device 92; or, the other side of the water supply pipe 81 is connected to the first circulation pipe 41 or the second circulation pipe 42 via the switching device 92.

[0180] In this embodiment, when the other side of the water supply pipe 81 is connected to the circulation pipe, the other side of the water supply pipe 81 can be directly or indirectly connected to the first circulation pipe 41 or the second circulation pipe 42, thereby achieving connectivity. Connectivity at other locations in this embodiment can also be understood as direct or indirect connection. The connection point can be located downstream of the switch device 92. Specifically, the relative position of the connection point to the switch device 92 can be referenced to the embodiment where the water tank 2 is located below the phase change tank 1, which will not be elaborated further here.

[0181] In the case where the switch device 92 is located on the first circulation pipe 41, one end of the water outlet pipe 82 is connected to the first circulation pipe 41 downstream of the switch device 92, and the water outlet pipe 82 is located outside the water tank 2. In the case where the switch device 92 is located on the second circulation pipe 42, one end of the water outlet pipe 82 is connected to the second circulation pipe 42 downstream of the switch device 92, and the water outlet pipe 82 is located outside the water tank 2.

[0182] by Figure 9 Taking the example where the switch device 92 is located on the second circulation pipe 42, the switch device 92 is installed on the second circulation pipe 42, and one end of the water outlet pipe 82 is connected to the second circulation pipe 42 downstream of the switch device 92, or one end of the water outlet pipe 82 is connected to the second circulation pipe 42 through the switch device 92. The water outlet pipe 82 is located outside the water tank 2.

[0183] In heat storage mode, the pump 6 is started, the switch device 92 is in the first state, the water heated by the heating rod 3 in the water tank 2 enters the heat exchanger 5 through the second circulation pipe 42, and then returns to the water tank 2 through the first circulation pipe 41 to form a circulating water circuit.

[0184] In water supply mode, when the switch device 92 is in the second state, the water in the water tank 2 cannot circulate between the water tank 2 and the heat exchanger 5. The switch device 92 is located in the second circulation pipeline 42, and the water supplied by the water source can pass through the water supply pipeline 81, the heat exchanger 5, the first circulation pipeline 41, and enter the water tank 2.

[0185] More specifically, when the switching device 92 is installed in the second circulation pipeline 42, the water supplied from the water source can pass through the water supply pipeline 81, part of the second circulation pipeline 42, the heat exchanger 5, the first circulation pipeline 41, and enter the water tank 2. Subsequently, the water flowing out of the water tank 2 is output to the outside through the outlet pipe 82 via part of the second circulation pipeline 42.

[0186] like Figure 10 As shown, taking the first circulation pipe 41 as an example, the switch device 92 is installed on the first circulation pipe 41. One end of the water outlet pipe 82 is connected to the first circulation pipe 41 downstream of the switch device 92, or one end of the water outlet pipe 82 is connected to the first circulation pipe 41 through the switch device 92. The water outlet pipe 82 is located outside the water tank 2.

[0187] In heat storage mode, the pump 6 is started, the switch device 92 is in the first state, the water heated by the heating rod 3 in the water tank 2 enters the heat exchanger 5 through the second circulation pipe 42, and then returns to the water tank 2 through the first circulation pipe 41 to form a circulating water circuit.

[0188] In water supply mode, when the switch device 92 is in the second state, the water in the water tank 2 cannot circulate between the water tank 2 and the heat exchanger 5. The switch device 92 is located in the first circulation pipeline 41, and the water supplied by the water source can enter the heat exchanger 5 through the water supply pipeline 81, the water tank 2, and the second circulation pipeline 42.

[0189] More specifically, when the switch device 92 is installed in the first circulation pipeline 41, the water supplied by the water source can pass through the water supply pipeline 81, part of the first circulation pipeline 41, the water tank 2, the second circulation pipeline 42, the heat exchanger 5, and part of the first circulation pipeline 41, and be output to the outside through the water outlet pipe 82.

[0190] In this embodiment, the first water outlet 412 is located at the lower part of the water tank 2. Since the first water outlet 412 is located at the lower part of the water tank 2, based on the characteristic that the water temperature in the water tank 2 gradually decreases from top to bottom, it can prevent the introduction of lower-temperature water from the outside into the water tank 2 from significantly disturbing the temperature field of the water tank 2, thereby helping to maintain a higher water temperature in the upper part of the water tank 2.

[0191] The technical effects resulting from the specific location of the water outlet pipe 82 can be referred to the detailed description of the above-described embodiments, and will not be repeated here.

[0192] like Figure 11 As shown, in one embodiment, the switching device 92 has at least a first port 921, a second port 922, and a third port 923. The first port 921 is used to connect to one side of the water supply pipe 81. The second port 922 and the third port 923 are connected to the first circulation pipe 41 or the second circulation pipe 42. The second port 922 is located downstream of the third port 923. When the switching device 92 is in the first state, the second port 922 and the third port 923 are connected. When the switching device 92 is in the second state, the first port 921 and the second port 922 are connected.

[0193] In this embodiment, the switching device 92 can be a multi-way valve, such as a switching valve. The switching device 92 can be located at the connection point between the water supply pipe 81 and the circulation pipe, specifically at the first connection portion 71. Specifically, the switching device 92 can include multiple ports, wherein the first port 921 can be used as a water inlet port, and the second port 922 and the third port 923 can be connected to the circulation pipe.

[0194] by Figure 11 Taking the switching device 92 installed in the first circulation pipe 41 as an example, during the heat storage stage, when the switching device 92 is in the first state, the second port 922 and the third port 923 are connected, the pump 6 is started, and the heated water in the water tank 2 returns to the water tank 2 through the second circulation pipe 42, the heat exchanger 5, and the first circulation pipe 41. During the water use stage, when the switching device 92 is in the second state, the first port 921 and the second port 922 are connected, and water supplied from an external water source enters the water tank 2 through the water supply pipe 81, part of the second circulation pipe 42, the heat exchanger 5, and the first circulation pipe 41. Subsequently, the water in the water tank 2 can flow out through part of the second circulation pipe 42 and the outlet pipe 82. During the water use stage, the externally supplied water flows sequentially through the heat exchanger 5 and the water tank 2, which are connected in series, providing the user with the maximum hot water supply, thereby meeting the user's large water consumption needs.

[0195] It should be noted that in the description of this application, the terms "first," "second," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0196] The various embodiments described in this specification are presented in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0197] The above are merely a few embodiments of this utility model. Although the embodiments disclosed in this utility model are as described above, the content is only for the purpose of facilitating understanding of this utility model and is not intended to limit this utility model. Any person skilled in the art to which this utility model pertains may make any modifications and changes in the form and details of the embodiments without departing from the spirit and scope disclosed in this utility model. However, the patent protection scope of this utility model shall still be determined by the scope defined in the appended claims.

Claims

1. An electric water heater, characterized in that, The electric water heater includes a water tank and a phase change tank. The phase change tank has a phase change material for heat storage and heat release. The phase change tank also includes a heat exchanger for communicating with the water tank. The electric water heater also includes a water supply pipe and a circulation pipe. The circulation pipe is used to connect the water tank and the heat exchanger. One side of the water supply pipe can be connected to a water source, and the other side of the water supply pipe can be connected to the heat exchanger and / or the circulation pipe and / or the water tank. A switching device is installed on the circulation pipeline, and the switching device has a first state and a second state. When the switching device is in the first state, the circulation pipeline can be connected, and the water in the water tank can circulate between the water tank and the heat exchanger; or, the water in the water tank cannot circulate between the water tank and the heat exchanger, and the water in the water supply pipeline can only flow into the water tank. When the switching device is in the second state, the water in the water tank cannot circulate between the water tank and the heat exchanger, and the water in the water supply pipeline can flow into the heat exchanger and the water tank in sequence, or the water in the water supply pipeline can flow into the water tank and the heat exchanger in sequence.

2. The electric water heater as described in claim 1, characterized in that, The circulation pipeline includes a first circulation pipeline and a second circulation pipeline. The first circulation pipeline has a first water inlet and a first water outlet. The first water inlet is located in the water tank and the first water outlet is located in the phase change tank. The second circulation pipeline has a second water inlet and a second water outlet. The second water inlet is located in the phase change tank and the second water outlet is located in the water tank. The switching device is installed on the first circulation pipeline or the second circulation pipeline.

3. The electric water heater as described in claim 2, characterized in that, The other side of the water supply pipeline is connected to the first circulation pipeline or the second circulation pipeline at a connection point, which is located downstream of the switching device; or, the other side of the water supply pipeline is connected to the first circulation pipeline or the second circulation pipeline through the switching device.

4. The electric water heater as described in claim 3, characterized in that, The first water inlet is located at the upper part of the water tank, the first water outlet is located at the upper part of the phase change tank, the second water inlet is located at the lower part of the phase change tank, and the second water outlet is located at the lower part of the water tank.

5. The electric water heater as described in claim 2, characterized in that, The switching device has at least a first port, a second port, and a third port. The first port is used to connect to the other side of the water supply pipeline. The second port and the third port are connected to the first circulation pipeline or the second circulation pipeline. The second port is located downstream of the third port. When the switching device is in the first state, the second port and the third port are connected. When the switching device is in the second state, the first port and the second port are connected.

6. The electric water heater as described in claim 2, characterized in that, When the switching device is in the second state, the water in the water tank cannot circulate between the water tank and the heat exchanger. The switching device is installed in the first circulation pipeline, and the other side of the water supply pipeline can be connected to the heat exchanger and / or the first circulation pipeline. Water supplied from the water source can enter the water tank through the water supply pipeline, the heat exchanger, and the second circulation pipeline. or, The switching device is installed in the second circulation pipeline. The other side of the water supply pipeline can be connected to the second circulation pipeline and / or the water tank. Water supplied from the water source can enter the heat exchanger through the water supply pipeline, the water tank, and the first circulation pipeline.

7. The electric water heater as described in claim 2, characterized in that, The circulation pipeline is also equipped with a pump.

8. The electric water heater as described in claim 7, characterized in that, The electric water heater also includes a heating element for heating the water in the tank. The electric water heater has a heat storage mode, in which the switching device is in the first state. The pump and the heating element start working simultaneously first, and then the pump or the heating element works independently.

9. The electric water heater as described in claim 7, characterized in that, The electric water heater also includes a heating element for heating the water in the tank. The electric water heater has a heat storage mode, in which the switching device is in the first state. The heating element starts working first, the pump starts working later, and the heating element continues to work or stops working.

10. The electric water heater as described in claim 7, characterized in that, The electric water heater also includes a heating element for heating the water in the tank. The electric water heater has a heat storage mode, in which the switching device is in the first state. The pump starts working first, the heating component starts working later, and the pump continues to work or stops working.

11. The electric water heater as described in claim 7, characterized in that, The first water inlet is located at the upper part of the water tank, the first water outlet is located at the lower part of the phase change tank, the second water inlet is located at the upper part of the phase change tank, and the second water outlet is located at the lower part of the water tank. The electric water heater has a heat storage mode and a water use mode. In the heat storage mode, the switch is in the first state, the pump is started, the circulation pipeline is open, and the water in the water tank can circulate between the water tank and the heat exchanger. In the water usage mode, the switch is in the first state, the pump is not started, the water in the water tank cannot circulate between the water tank and the heat exchanger, and the water in the water supply pipeline can flow into the water tank only through the circulation pipeline.

12. The electric water heater as described in claim 2, characterized in that, The electric water heater also includes a water outlet pipe, one end of which is connected to the circulation pipe, and / or the water outlet pipe passes through the water tank.

13. The electric water heater as described in claim 12, characterized in that, The switching device is installed on the first circulation pipeline. One end of the water outlet pipe is connected to the first circulation pipeline located upstream of the switching device, or one end of the water outlet pipe is connected to the first circulation pipeline through the switching device. The water outlet pipe is located outside the water tank.

14. The electric water heater as described in claim 12, characterized in that, The switching device is installed on the second circulation pipeline. One end of the water outlet pipe is connected to the second circulation pipeline located upstream of the switching device, or one end of the water outlet pipe is connected to the second circulation pipeline through the switching device. The water outlet pipe is located outside the water tank.

15. The electric water heater according to claim 2, wherein The electric water heater also includes a heating element for heating the water in the tank.

16. The electric water heater as described in claim 15, characterized in that, The first water inlet is located at the upper part of the water tank, the first water outlet is located at the upper part of the phase change tank, the second water inlet is located at the lower part of the phase change tank, the second water outlet is located at the lower part of the water tank, and the heating component includes a heating rod, with at least one heating rod located at the upper middle part or bottom of the water tank.

17. The electric water heater as described in claim 1, characterized in that, The phase change tank is located above the water tank.

18. The electric water heater as described in claim 1, characterized in that, A pump is installed on the circulation pipeline. The circulation pipeline includes a first circulation pipeline and a second circulation pipeline. The first circulation pipeline has a first water inlet and a first water outlet. The first water inlet is located at the phase change tank and the first water outlet is located at the water tank. The second circulation pipeline has a second water inlet and a second water outlet. The second water inlet is located at the water tank and the second water outlet is located at the phase change tank. The switching device is installed on the first circulation pipeline or the second circulation pipeline.

19. The electric water heater as described in claim 18, characterized in that, The other side of the water supply pipeline is connected to the first circulation pipeline or the second circulation pipeline at a connection point, which is located downstream of the switching device; or, the other side of the water supply pipeline is connected to the first circulation pipeline or the second circulation pipeline through the switching device.

20. The electric water heater as described in claim 19, characterized in that, The first water outlet is located at the lower part of the water tank.

21. The electric water heater as described in claim 18, characterized in that, The switching device has at least a first port, a second port, and a third port. The first port is used to connect to one side of the water supply pipeline. The second port and the third port are connected to the first circulation pipeline or the second circulation pipeline. The second port is located downstream of the third port. When the switching device is in the first state, the second port and the third port are connected. When the switching device is in the second state, the first port and the second port are connected.

22. The electric water heater as described in claim 18, characterized in that, When the switching device is in the second state, the water in the water tank cannot circulate between the water tank and the heat exchanger. The switching device is installed in the first circulation pipeline, and the water supplied by the water source can enter the heat exchanger through the water supply pipeline, the water tank, and the second circulation pipeline; or, The switching device is installed in the second circulation pipeline. Water supplied from the water source can pass through the water supply pipeline, the heat exchanger, the first circulation pipeline, and enter the water tank.

23. The electric water heater as described in claim 18, characterized in that, The electric water heater also includes a water outlet pipe, one end of which is connected to the circulation pipe or one end of which is connected to the circulation pipe via the switch device, and / or the water outlet pipe passes through the water tank.

24. The electric water heater as described in claim 23, characterized in that, The switching device is installed on the first circulation pipeline. One end of the water outlet pipe is connected to the first circulation pipeline located downstream of the switching device, or one end of the water outlet pipe is connected to the first circulation pipeline through the switching device. The water outlet pipe is located outside the water tank.

25. The electric water heater as described in claim 23, characterized in that, The switching device is installed on the second circulation pipeline. One end of the water outlet pipe is connected to the second circulation pipeline downstream of the switching device, or one end of the water outlet pipe is connected to the second circulation pipeline through the switching device. The water outlet pipe is located outside the water tank.

26. The electric water heater as described in claim 18, characterized in that, The phase change chamber is located below the water chamber.

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