CN115493184A

CN115493184A - Domestic hot water storage device

Info

Publication number: CN115493184A
Application number: CN202211140457.3A
Authority: CN
Inventors: 嵇永飞; 梁辉
Original assignee: Dongguan Arcio Heat Energy Equipment Co ltd
Current assignee: Dongguan Arcio Heat Energy Equipment Co ltd
Priority date: 2022-09-20
Filing date: 2022-09-20
Publication date: 2022-12-20

Abstract

The invention relates to a domestic hot water storage device, comprising: the water supply system comprises a water storage tank, a water supply module, a water return module and a controller. The water storage tank is provided with a water outlet pipe, a water return pipe, a two-way pipe, a first temperature sensor and a second temperature sensor. The water supply module includes: a main water supply path and a bypass water supply path. The main water supply path is provided with a first one-way valve. The water supply bypass is provided with: the water mixing device comprises an electric water mixing valve, a circulating water pump, a third temperature sensor and a three-way reversing valve. The water return module includes: a water return main path and a water return bypass. And a fourth temperature sensor is arranged on the water return main path. The moisturizing module includes: a water replenishing main path and a water replenishing bypass path. The water supplementing main path is provided with a second one-way valve and a water flow switch. The water heater is prevented from being frequently used, the noise is reduced, the frequent short-time starting of the water heater is reduced, and the service life of the water heater is prolonged. A large amount of hot water can be prestored by utilizing the water storage tank, the requirement on the power of the water heater is low, and the problems of overhigh water temperature and sudden cooling and sudden heating in summer are solved.

Description

Domestic hot water storage device

Technical Field

The invention relates to the technical field of hot water supply equipment, in particular to a domestic hot water storage device.

Background

In daily life, hot water (generally 30-60 ℃) is often used for cleaning, bathing and the like. The current common domestic hot water supply mode is as follows: cold water in tap water is heated to hot water of a preset temperature by a water heater (gas combustion heating or electric heating), and then is delivered to various water use terminals such as a faucet, a shower head and the like through a pipeline. When the water heater is turned off, the hot water supply is cut off, and the hot water staying in the pipe is continuously radiated to be cold water. Therefore, when the user just turns on the water use terminal, cold water is initially discharged and heated hot water is discharged thereafter. In order to improve the user experience and enable the user to directly discharge hot water when the water using terminal is just opened, some manufacturers develop a zero-cold-water design. By zero cold water is meant that the temperature of the liquid in the pipe connecting the water terminals is maintained within a preset range (i.e. always in a hot water state).

In order to realize zero cold water supply, most of the conventional hot water supply equipment is provided with a circulating pump and a temperature sensor on a pipeline, when the temperature sensor detects that the temperature of liquid in the pipeline is lower than a preset value, the circulating pump is triggered to drive the liquid in the pipeline to circulate continuously, and the liquid is heated to a preset range by using a water heater.

The drawbacks of the above-mentioned conventional design are: firstly, the liquid retained in the pipeline dissipates heat very rapidly, so that the circulating water pump and the water heater can be frequently touched to work, the noise is obvious, the water heater can be frequently started in a short time, and the service life of the water heater is greatly shortened. Secondly, if a user needs large-flow hot water supply, in order to meet the heating requirement, a high-power water heater needs to be installed, and the low-power water heater is limited by the minimum heat load (namely the minimum requirement for starting the water heater), so that the problems of overhigh water temperature and sudden cooling and sudden heating in summer are easily caused.

Disclosure of Invention

Based on the above, the invention provides the domestic hot water storage device, which avoids frequent use of the water heater, can prestore a large amount of hot water by using the water storage tank, meets the requirement of large flow of water, and has lower power requirement on the water heater.

A domestic hot water storage device comprising:

a water storage tank; the water storage tank is provided with a water outlet pipe, a water return pipe and a two-way pipe; the water outlet pipe extends to the upper layer of the water storage tank; the water return pipe extends to the upper layer of the water storage tank and is deeper than the water outlet pipe; the bidirectional pipe extends to the lower layer of the water storage tank; the water storage tank is provided with a first temperature sensor and a second temperature sensor; the first temperature sensor is positioned on the upper layer of the water storage tank; the second temperature sensor is positioned at the lower layer of the water storage tank;

a water supply module connected with the water storage tank; the water supply module includes: a main water supply path and a bypass water supply path connected in parallel to the main water supply path; the water supply main path is connected between the water outlet pipe and the inlet end of the pipeline of the water using terminal, and is provided with a first one-way valve connected with the water outlet pipe; the water supply bypass is provided with: the water mixing device comprises an electric water mixing valve, a circulating water pump, a third temperature sensor and a three-way reversing valve; the electric water mixing valve, the circulating water pump and the three-way reversing valve are sequentially connected in series; the first inlet end of the electric water mixing valve is connected between the water outlet pipe and the first one-way valve, and the outlet end of the electric water mixing valve is connected with the circulating water pump; the circulating water pump is connected with the inlet end of the three-way reversing valve; the first outlet end of the three-way reversing valve is connected with the inlet end of a pipeline of the water using terminal, and the second outlet end of the three-way reversing valve is connected with the inlet end of the water heater; the third temperature sensor is connected between the circulating water pump and the three-way reversing valve;

a water return module connected with the water storage tank; the water return module includes: a backwater main path and a backwater bypass which are arranged in parallel; the water return main path is connected between the water return pipe and the outlet end of the pipeline of the water using terminal, and the water return main path is provided with a fourth temperature sensor; the water return bypass is connected between the water return pipe and the outlet end of the water heater;

the water replenishing module is connected with the water storage tank; the moisturizing module includes: the water replenishing main path and the water replenishing bypass are arranged in parallel; the water replenishing main path is connected between the bidirectional pipe and the tap water network; the water replenishing main path is provided with a second one-way valve and a water flow switch which are connected in series; the water supplementing bypass is connected between the bidirectional pipe and the second inlet end of the electric water mixing valve; and

a controller; the controller is respectively and electrically connected with the first temperature sensor, the second temperature sensor, the third temperature sensor, the fourth temperature sensor, the electric water mixing valve, the circulating water pump and the three-way reversing valve.

In the domestic hot water storage device, the water storage tank is used for storing hot water. When zero cold water circulation is needed to be realized in a pipeline of the water using terminal, the circulating water pump is started, hot water is pumped from the water storage tank to enter the pipeline of the water using terminal, and cold water originally retained in the pipeline of the water using terminal flows back to the water storage tank to be mixed with the hot water in the water storage tank, so that the zero cold water circulation is realized. The above design stores hot water by using the storage tank, and replaces cold water staying in the pipeline of the water using terminal by controlling the circulation flow of the hot water in the pipeline of the water using terminal, and makes the cold water flow back to the storage tank to be mixed with the hot water, thereby achieving zero cold water supply. This design has avoided frequent use water heater, and the noise reduction reduces the frequent short time start-up of water heater, is favorable to prolonging the life of water heater. And utilize the storage water tank can prestore a large amount of hot water, satisfy large-traffic water demand, it is lower to the power requirement of water heater, alleviate summer high temperature and the problem of suddenly cooling and suddenly heating.

In one embodiment, the refill module further comprises: a water pressure sensing device connected with the bidirectional pipe; the water pressure sensing device is electrically connected with the controller. The water pressure sensing device can detect the water pressure of the water storage tank, and the condition that the circulating water pump idles when the tap water network is cut off is avoided.

In one embodiment, the main water replenishing path is further provided with a safety relief valve. When the water replenishing main path is abnormal or the water in the water storage tank is expanded by heat to cause the water pressure to reach a critical value, the pressure can be automatically released through the safety relief valve, and the running safety of the equipment is improved.

In one embodiment, the water replenishing main path is also provided with an expansion tank. The expansion tank can absorb the expansion volume generated by heating the water body in the water storage tank so as to prevent the water pressure of the water storage tank from rising rapidly and improve the running safety of the equipment.

In one embodiment, the outer periphery of the water storage tank is provided with a heat insulation plate. The heat insulation plate is used for reducing heat loss of the water storage tank and improving the heat insulation effect of the water storage tank.

In one embodiment, the controller has a demand period setting function and an artificially activated zero cold water function. The zero cold water circulation can be set at a specific demand time through the demand period setting function, and the operation frequency of the equipment is reduced. And the artificial activation of the zero cold water function may allow the user to artificially trigger the zero cold water cycle during non-demand periods.

In one embodiment, the water replenishing main path is further provided with: a first electrically controlled valve connected to the two-way pipe; the water supplementing bypass is provided with a second electric control valve connected with the two-way pipe; the first electric control valve and the second electric control valve are respectively and electrically connected with the controller. The first electric control valve is matched with the second electric control valve, so that the accuracy of controlling the water flow direction of the water replenishing module can be improved.

In one embodiment, the main water outlet path is provided with a third electric control valve connected with the water outlet pipe; the third electric control valve is electrically connected with the controller. The third electric control valve can improve the accuracy of controlling the water flow direction of the water outlet module.

Drawings

Fig. 1 is a schematic view of a domestic hot water storage apparatus according to an embodiment of the present invention;

fig. 2 is a state view illustrating the domestic hot water storage apparatus shown in fig. 1 in use;

fig. 3 is a state diagram of a zero cold water circulation state of the domestic hot water storage device shown in fig. 1;

fig. 4 is a hot water use state diagram of the domestic hot water storage apparatus shown in fig. 1;

fig. 5 is a heat supplement state diagram of the domestic hot water storage apparatus shown in fig. 1;

fig. 6 is a state diagram of hot water usage and heat supplement in parallel in the domestic hot water storage device shown in fig. 1.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, embodiments accompanying figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, but are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and are not to be construed as limiting the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be interconnected within two elements or in a relationship where two elements interact with each other unless otherwise specifically limited. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the second feature or the first and second features may be indirectly contacting each other through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature "under," "beneath," and "under" a second feature may be directly under or obliquely under the second feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. As used herein, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are for purposes of illustration only and do not denote a single embodiment.

As shown in fig. 1 to 6, a domestic hot water storage device according to an embodiment of the present invention is provided.

For convenience of explanation and reduction of interference of the marked line with the water path diagram, in fig. 1 to 6, the components are marked in the form of english symbols.

As shown in fig. 1, the domestic hot water storage apparatus includes: a water storage tank WT, a water supply module, a water return module, a water replenishment module, and a controller (not shown). Wherein the storage tank WT is used to store hot water (the temperature of the stored hot water is generally set to be greater than the maximum temperature of daily water use of the user). The water return module, the water supply module and the water replenishing module are respectively connected with the water storage tank WT. The water supply module is used for pumping hot water from the water storage tank WT to a pipeline of the water terminal S (in the embodiment, the water terminal S is shown by taking a shower head as an example). The water return module is used for communicating the water storage tank WT to form a circulating waterway. The water supplement module is used for supplementing cold water to the water storage tank WT and also for providing cold water to be mixed with the hot water output by the water supply module to adjust the temperature of the hot water delivered to the pipeline of the water terminal S (mainly, to lower the temperature of the water).

As shown in fig. 2, when installed, the water supply module is connected to the inlet end C of the pipeline of the water terminal S and the inlet end D of the water heater H, respectively. The water return module is respectively connected with the outlet end A of the pipeline of the water using terminal S and the outlet end B of the water heater H. The water replenishing module is respectively connected with an interface E of a tap water network and the water supply module.

Hereinafter, the domestic hot water storage apparatus will be further described with reference to fig. 1 to 6.

As shown in fig. 1 and 2, the water storage tank WT is provided with a water outlet pipe X2, a water return pipe X3, and a two-way pipe X1. The water outlet pipe X2 extends to the upper layer of the water storage tank WT. The water return pipe X3 extends to the upper layer of the water storage tank WT and is deeper than the water outlet pipe X2. The bidirectional pipe X1 extends to the lower layer of the storage tank WT. The water storage tank WT is provided with a first temperature sensor T2 and a second temperature sensor T3. The first temperature sensor T2 is located in an upper layer of the water storage tank WT. The second temperature sensor T3 is located at the lower layer of the water storage tank WT.

Further, in the present embodiment, an outer circumferential side of the water storage tank WT may be provided with a heat insulating plate. The heat insulation plate is used for reducing heat loss of the water storage tank WT and improving the heat insulation effect of the water storage tank WT.

As shown in fig. 2, the water supply module includes: the water supply main path and the water supply bypass connected in parallel with the water supply main path. Wherein, the main water supply path is connected between the water outlet pipe X2 and the inlet end C of the pipeline of the water terminal S, and the main water supply path is provided with a first one-way valve C2 connected with the water outlet pipe X2. The water supply bypass is provided with: the water mixing device comprises an electric water mixing valve M2, a circulating water pump P, a third temperature sensor T1 and a three-way reversing valve M1. The electric water mixing valve M2, the circulating water pump P and the three-way reversing valve M1 are sequentially connected in series. A first inlet end (the left end of the M2 in the figure) of the electric water mixing valve M2 is connected between the water outlet pipe X2 and the first one-way valve C2, and an outlet end (the top end of the M2 in the figure) of the electric water mixing valve M2 is connected with the circulating water pump P. The circulating water pump P is connected with the inlet end (the bottom end of M1 in the figure) of the three-way reversing valve M1. The first outlet end (left end of M1 in the figure) of the three-way reversing valve M1 is connected with the inlet end C of the pipeline of the water using terminal S, and the second outlet end (right end of M1 in the figure) of the three-way reversing valve M1 is connected with the inlet end D of the water heater H. And the third temperature sensor T1 is connected between the circulating water pump P and the three-way reversing valve M1.

As shown in fig. 2, the water return module includes: a backwater main path and a backwater bypass which are arranged in parallel. The water return main path is connected between the water return pipe X3 and the outlet end A of the pipeline of the water using terminal S, and the water return main path is provided with a fourth temperature sensor T4. The return water bypass is connected between the return water pipe X3 and the outlet end B of the water heater H.

As shown in fig. 2, the water replenishing module includes: the water replenishing main path and the water replenishing bypass are arranged in parallel. The water replenishing main path is connected between the bidirectional pipe X1 and an interface E of a tap water network. The main water replenishing path is provided with a second one-way valve C1 and a water flow switch K1 which are connected in series. The water replenishing bypass is connected between the bidirectional pipe X1 and the second inlet end (the right end of M2 in the drawing) of the electric mixing valve M2.

In this embodiment, the controller is electrically connected to the first temperature sensor T2, the second temperature sensor T3, the third temperature sensor T1, the fourth temperature sensor T4, the electric water mixing valve M2, the circulating water pump P, and the three-way reversing valve M1, respectively.

In order to improve the safety of the equipment operation, the domestic hot water storage device can be further improved as follows:

for example, as shown in fig. 1 and fig. 2, in this embodiment, the water replenishing module may further include: a water pressure sensing device K2 connected with the bidirectional pipe X1. The water pressure sensing device K2 is electrically connected with the controller. The water pressure sensing device K2 can detect the water pressure of the water storage tank WT, and the condition that the circulating water pump idles when the water supply network is cut off is avoided. For example, when the water pressure sensing means K2 detects that the water pressure value is lower than a preset value, the controller may issue an alarm signal and lock the operation state of the circulation water pump P to stop. In this embodiment, the water pressure sensing device K2 is specifically a water pressure switch, and in other embodiments, it may also be a hydraulic pressure sensor.

For another example, as shown in fig. 1 and 2, in the present embodiment, the main water replenishing path may further include a safety relief valve K3. When the water supplementing main path is abnormal or the water in the water storage tank WT is subjected to thermal expansion, the water pressure reaches a critical value, the pressure can be automatically relieved through the safety relief valve K3, and the operation safety of the equipment is improved.

For another example, as shown in fig. 1 and fig. 2, in the present embodiment, the water replenishing main path may be further provided with an expansion tank ET. The expansion tank ET can absorb the expansion volume generated by heating the water in the water storage tank WT, so that the water pressure of the water storage tank WT is prevented from rising quickly, and the running safety of equipment is improved.

In this embodiment, the flow direction of the liquid can be controlled based on the principle that the liquid flows from a high pressure to a low pressure. In order to control the flowing direction of the flowing water more accurately, an electric control valve connected with the controller can be arranged, and the flowing of the flowing water is ensured according to a preset operation scheme.

For example, in some embodiments, the water replenishing main road may be further provided with: a first electrically controlled valve connected to the two-way pipe X1. The water supplementing bypass is provided with a second electric control valve connected with the two-way pipe X1. The first electric control valve and the second electric control valve are respectively and electrically connected with the controller. The first electric control valve is matched with the second electric control valve, so that the accuracy of water flow direction control of the water replenishing module can be improved. For example, a first electric control valve is installed at the right end of the water pressure sensing device K2 in the drawing, and a second electric control valve is installed between the electric mixing valve M2 and the water pressure sensing device K2 in the drawing.

For another example, in some embodiments, the main outlet path may be provided with a third electrically controlled valve connected to outlet pipe X2. The third electric control valve is electrically connected with the controller. The third electric control valve can improve the accuracy of controlling the water flow direction of the water outlet module. For example, a third electrically controlled valve is installed at a lower end position of the first check valve C2.

The working principle is briefly described as follows:

1. general overview:

as shown in fig. 2, the storage tank WT is used to store hot water. When zero cold water circulation needs to be realized in the pipeline of the water terminal S, the circulating water pump P is started, hot water is pumped from the water storage tank WT to enter the pipeline of the water terminal S, and cold water originally remained in the pipeline of the water terminal S flows back into the water storage tank WT to be mixed with hot water in the water storage tank WT, so that zero cold water circulation is realized.

2. Zero cold water circulation mode:

as shown in fig. 3, the water use terminal S is in a closed state. When the temperature detected by the fourth temperature sensor T4 is lower than the preset value, the three-way directional valve M1 is switched to the left side, the circulating water pump P is started, hot water is pumped from the upper layer of the water storage tank WT through the water outlet pipe X2 and conveyed into the pipeline of the water using terminal S until the temperature detected by the fourth temperature sensor T4 reaches the preset value.

Here, it is considered that during some time periods when hot water is not needed, the device may run a zero cold water cycle at intervals, which is mostly useless, and is not beneficial to energy saving. Thus, in this embodiment, the controller may have a demand period setting function and an artificially activated zero cold water function. The zero cold water circulation can be set at a specific demand time through the demand period setting function, and the operation frequency of the equipment is reduced. And the artificial activation of the zero cold water function may allow the user to artificially trigger the zero cold water cycle during non-demand periods.

For example, the zero cooling water circulation operation is started when the temperature detected by the fourth temperature sensor T4 is lower than a preset value and during a demand time period or when zero cooling water is activated manually.

3. Hot water use mode:

as shown in fig. 4, the water storage tank S is in an open state. Hot water flows out of the outlet pipe X2 of the water storage tank WT, and at the same time, tap water (cold water) is replenished into WT from the bidirectional pipe X1. At the moment, the water flow switch K1 is closed, the three-way reversing valve M1 is switched to the left side, and the circulating water pump P is started to increase pressure and flow. The left and right sides of the electric mixing valve M2 are simultaneously opened, and the respective opening degrees (mixing ratio of cold water and hot water) are adjusted according to the difference between the third temperature sensor T1 and the target temperature set by the user, and the temperature of the mixed water obtained after adjustment is equal to the target temperature and enters the circulating water pump P from the upper end of the electric mixing valve M2.

In designing the capacity of the storage tank WT, it is prioritized that the capacity can be such that the heat provided by the storage tank WT can meet the heat demand of the water during a set period of time, so the situation where hot water usage and heat replenishment coexist is not considered here (see 4.2 below, this mode is a very special case, generally without consideration, or priority of the operating conditions is set to guide the usage to the user).

4. Heat supplement mode:

4.1. as shown in fig. 5, the water use terminal S is in a closed state. The temperatures detected by the second temperature sensor T3 and the first temperature sensor T2 are gradually decreased as the tap water (cold water) is replenished due to the use of hot water or naturally radiated in a non-use state. When the temperature detected by the first temperature sensor T2 is lower than the preset value, the three-way reversing valve M1 is switched to the right side, the electric water mixing valve M2 is adjusted to the right side and fully opened (left side closed), the cold water at the lower layer of the water storage tank WT is conveyed to the water heater H through the two-way pipe X1 to be heated, and the heated water flows back to the upper layer of the water storage tank WT through the water return pipe X3 and stops until the temperature detected by the second temperature sensor T3 reaches the preset value.

4.2. As shown in fig. 6, the water service terminal S is in an open state. As the hot water is continuously used, the temperatures detected by the second temperature sensor T3 and the first temperature sensor T2 are gradually decreased. When the temperature detected by the first temperature sensor T2 is lower than the preset value, the three-way reversing valve M1 is switched to the right side, the electric water mixing valve M2 is adjusted to the right side and is fully opened (the left side is closed), cold water at the lower layer of the water storage tank WT is conveyed to the water heater H through the two-way pipe X1 to be heated, the heated water flows back to the upper layer of the water storage tank WT through the water return pipe X3, meanwhile, the water storage tank WT continuously conveys hot water to a pipeline of a water terminal S through the water outlet pipe X2, and the use mode of the regenerated water is switched until the temperature detected by the second temperature sensor T3 reaches the preset value. At this time, under the action of the circulating water pump P, part of the water output from the water storage tank WT is delivered to the water heater H to be heated, and the other part of the water output from the water storage tank WT flows into the pipeline of the water terminal S from the main water supply pipe.

In addition, the operation mode of the domestic hot water storage apparatus may be set to priority, for example, the zero cold water circulation function is artificially triggered to the highest priority, and then the heat supplement function, the hot water use function, and the automatic zero cold water circulation function are sequentially performed.

The domestic hot water storage apparatus stores hot water using the storage tank WT, and by controlling the circulation flow of hot water in the pipe of the water use terminal, cold water staying in the pipe of the water use terminal is replaced and the cold water is made to flow back into the storage tank WT to be mixed with the hot water, thereby achieving zero cold water supply. This design has avoided frequent use water heater H, and the noise reduction reduces the frequent short time start of water heater H, is favorable to prolonging the life to water heater H. And a large amount of hot water can be prestored by using the water storage tank, the requirement on large-flow water consumption is met, the power requirement on the water heater H is lower, and the problems of overhigh water temperature and sudden cooling and sudden heating in summer are solved.

All possible combinations of the technical features in the above embodiments may not be described for the sake of brevity, but should be considered as being within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.

The above examples only express the preferred embodiments of the present invention, and the description thereof is specific and detailed, but not to be understood as the limitation of the invention patent scope. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the invention, and these changes and modifications are all within the scope of the invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A domestic hot water storage device, comprising:

the water supply module is connected with the water storage tank; the water supply module includes: a main water supply path and a water supply bypass connected in parallel to the main water supply path; the main water supply path is connected between the water outlet pipe and the inlet end of the pipeline of the water using terminal, and is provided with a first one-way valve connected with the water outlet pipe; the water supply bypass is provided with: the water mixing device comprises an electric water mixing valve, a circulating water pump, a third temperature sensor and a three-way reversing valve; the electric water mixing valve, the circulating water pump and the three-way reversing valve are sequentially connected in series; the first inlet end of the electric water mixing valve is connected between the water outlet pipe and the first one-way valve, and the outlet end of the electric water mixing valve is connected with the circulating water pump; the circulating water pump is connected with the inlet end of the three-way reversing valve; the first outlet end of the three-way reversing valve is connected with the inlet end of a pipeline of the water using terminal, and the second outlet end of the three-way reversing valve is connected with the inlet end of the water heater; the third temperature sensor is connected between the circulating water pump and the three-way reversing valve;

the water return module is connected with the water storage tank; the water return module comprises: a backwater main path and a backwater bypass which are arranged in parallel; the water return main path is connected between the water return pipe and the outlet end of the pipeline of the water using terminal, and a fourth temperature sensor is arranged on the water return main path; the return water bypass is connected between the return water pipe and the outlet end of the water heater;

the water replenishing module is connected with the water storage tank; the moisturizing module includes: the water replenishing main path and the water replenishing bypass are arranged in parallel; the water replenishing main path is connected between the bidirectional pipe and a tap water network; the water supplementing main path is provided with a second one-way valve and a water flow switch which are connected in series; the water supplementing bypass is connected between the bidirectional pipe and the second inlet end of the electric water mixing valve; and

2. The domestic hot water storage device of claim 1, wherein said refill module further comprises: the water pressure sensing device is connected with the bidirectional pipe; the water pressure sensing device is electrically connected with the controller.

3. The domestic hot water storage device of claim 1, wherein the main water replenishing path is further provided with a safety relief valve.

4. The domestic hot water storage device of claim 1, wherein said main refill circuit is further provided with an expansion tank.

5. The domestic hot water storage device of claim 1, wherein the storage tank is provided with a heat insulating plate on the outer circumferential side.

6. The domestic hot water storage device of claim 1, wherein said controller has a demand period setting function and an artificially activated zero cold water function.

7. The domestic hot water storage device of claim 1, wherein said main refill path is further provided with: a first electrically controlled valve connected to the bidirectional pipe; the water supplementing bypass is provided with a second electric control valve connected with the bidirectional pipe; the first electric control valve and the second electric control valve are respectively and electrically connected with the controller.

8. The domestic hot water storage device of claim 1, wherein said main effluent path is provided with a third electrically controlled valve connected to said outlet pipe; the third electric control valve is electrically connected with the controller.