Electric water heating system with sewage heat recovery function

Abstract

The utility model discloses an electric water heating system with a sewage heat recovery function. The electric water heating system comprises an electric water heater and a sewage heat recovery device, the electric water heater comprises a heat storage area, a heat exchange area and a heat backflow area. The sewage heat recovery device comprises a sewage heat exchange mechanism and a heat recovery mechanism, and the heat recovery mechanism is connected with the heat backflow area and stores heat in the heat backflow area. According to the electric water heating system with the sewage heat recovery function, the sewage heat recovery device and the heat backflow area are additionally arranged, the sewage heat recovery device collects heat in sewage used by the water heater and stores the heat in the heat backflow area, the water heater can utilize the heat in the heat backflow area, and the water using time of the electric water heater is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of electric water heaters, in particular to an electric water heater system with sewage heat recovery. Background Art

[0002] Electric water heaters mainly convert electrical energy into the internal energy of water. Under the premise of ensuring the safety of electricity use, electric water heaters have many advantages: high safety, simple and convenient water pipe laying, precise temperature adjustment, low maintenance cost, environmentally friendly and no exhaust gas generation, no environmental dependence on installation, etc. Based on these advantages, in recent years, despite the emergence of a variety of water heater options on the market, electric water heaters still maintain a large market share. Moreover, as people's pursuit of quality of life continues to improve, the requirements for the performance and functions of water heaters are also constantly upgrading, especially for constant water temperature and water use time.

[0003] After research, it was found that in the existing technology, the research direction of electric water heaters is mainly to extend the electric water heater's own heat storage and mixed water heat exchange time, but it is rare to recover the heat of sewage after the water heater is used, and the recovered heat is used to extend the water use time of the electric water heater. Utility Model Content

[0004] In order to overcome at least one of the defects described in the above-mentioned prior art, the utility model provides an electric water heating system with sewage heat recovery. By adding a sewage heat recovery device and a heat reflux zone, the sewage heat recovery device collects the heat in the sewage after use by the water heater and stores it in the heat reflux zone. The water heater can utilize the heat in the heat reflux zone to extend the water use time of the electric water heater.

[0005] The technical solution adopted by the utility model to solve the problem is:

[0006] An electric hot water system with sewage heat recovery comprises an electric water heater and a sewage heat recovery device; the electric water heater comprises a heat storage area, a heat exchange area and a heat reflux area; the sewage heat recovery device comprises a sewage heat exchange mechanism and a heat recovery mechanism, the heat recovery mechanism is connected to the heat reflux area to store heat in the heat reflux area.

[0007] Furthermore, the heat reflow zone is provided with a second inlet, a first outlet and a second outlet; the first outlet is connected to the heat exchange zone;

[0008] The heat recovery mechanism includes a first heat exchange device, which includes a first heat exchange component, and the two ends of the first heat exchange component are respectively connected to the second inlet and the second outlet; the first heat exchange component exchanges heat with the sewage heat exchange mechanism, and refluxes and stores heat in the heat reflux area.

[0009] Furthermore, the end of the first heat exchange component connected to the second outlet is also connected to a cold water pipe, and the cold water exchanges heat with the sewage heat exchange mechanism in the first heat exchange component to obtain preheated water, and the preheated water flows back to the heat reflux area through the second inlet.

[0010] Furthermore, when the temperature of the preheated water in the heat recirculation zone is lower than the sewage heat exchange temperature threshold, the preheated water in the heat recirculation zone enters the first heat exchange component through the second outlet to exchange heat with the sewage heat exchange mechanism;

[0011] When the temperature of the preheated water in the heat reflux zone is not lower than the sewage heat exchange threshold temperature, the cold water pipe transports cold water into the first heat exchange component, the cold water exchanges heat with the sewage heat exchange mechanism in the first heat exchange component to obtain preheated water again, and the preheated water flows back to the heat reflux zone through the second inlet.

[0012] Furthermore, the first heat exchange device further includes a second heat exchange component, which is placed in the heat reflow zone and has two ends connected to the first heat exchange component through the second inlet and the second outlet respectively;

[0013] The first heat exchange component and the second heat exchange component are filled with a first heat exchange medium, and the first heat exchange medium circulates in the first heat exchange component and the second heat exchange component;

[0014] The first heat exchange medium exchanges heat with the sewage heat exchange mechanism in the first heat exchange component, and the first heat exchange medium stores heat in the heat reflux area through the second heat exchange component.

[0015] Furthermore, a first inlet is provided on the heat reflow zone, and the first inlet is connected to a cold water pipe, and the cold water pipe replenishes cold water into the heat reflow zone, and the cold water exchanges heat with the first heat exchange medium in the second heat exchange component.

[0016] Furthermore, the first heat exchange medium is a heat conducting medium, and the heat conducting medium includes but is not limited to tap water, purified water, heat conducting oil or heat conducting solution.

[0017] Further, the sewage heat exchange mechanism includes a third heat exchange component for exchanging heat with the first heat exchange component;

[0018] The third heat exchange component includes a heat exchange insulation box for collecting sewage with a temperature higher than the sewage heat exchange temperature threshold. The first heat exchange component is placed in the heat exchange insulation box and immersed in the sewage. The first heat exchange component directly contacts and exchanges heat with the sewage.

[0019] Further, the sewage heat exchange mechanism includes a third heat exchange component for exchanging heat with the first heat exchange component;

[0020] The third heat exchange component includes a heat exchange insulation box and a sewage coil placed in the heat exchange insulation box. Sewage with a temperature higher than the sewage heat exchange temperature threshold enters the sewage coil, and the first heat exchange component exchanges heat with the sewage coil.

[0021] Furthermore, the sewage heat exchange mechanism also includes a sewage filter device arranged in front of the third heat exchange component, the sewage filter device includes a filter floor drain and a filter box connected to the rear of the filter floor drain, the filter box is provided with a sewage inlet, a sewage outlet and a sewage outlet, the sewage inlet is connected to the filter floor drain, the sewage outlet is connected to the third heat exchange component, and the sewage drainage is connected to the sewage pipe;

[0022] The filter box is provided with a first filter mesh layer and a second filter mesh layer, the first filter mesh layer is placed below the second filter mesh layer, and the mesh aperture of the first filter mesh layer is smaller than the mesh aperture of the second filter mesh layer;

[0023] The sewage outlet is arranged at the bottom of the filter box, the sewage outlet is arranged at the top of the filter box, and the sewage inlet is arranged below the first filter screen layer and not close to the bottom of the filter box;

[0024] The first filter mesh layer and the second filter mesh layer are both lightweight floating plates, and a limit block is fixedly provided at the sewage inlet position. When the water level in the filter box drops, the first filter mesh layer and the second filter mesh layer drop with the water level, and the limit block limits the lowest position of the first filter mesh layer.

[0025] Furthermore, the heat storage area includes a first heat storage tank and a second heat storage tank isolated from each other, and the first heat storage tank and the second heat storage tank are respectively provided with a first heating module and a second heating module;

[0026] A fourth heat exchange component is connected between the first heat storage tank and the second heat storage tank, and the fourth heat exchange component is arranged in the heat exchange area;

[0027] The first heat storage tank or the second heat storage tank is filled with a first heat storage medium, and the first heat storage medium circulates between the first heat storage tank and the second heat storage tank through the fourth heat exchange component;

[0028] The first heating module heats the first heat storage medium in the first heat storage tank, and the heated first heat storage medium enters the second heat storage tank through the fourth heat exchange component; or, the second heating module heats the first heat storage medium in the second heat storage tank, and the heated first heat storage medium enters the first heat storage tank through the fourth heat exchange component;

[0029] The cold water pipe is connected with a water-use heat exchange component, and the water-use heat exchange component is placed in the heat exchange area;

[0030] The first outlet of the heat reflow zone is connected to the water-use heat exchange component and is connected to the liquid inlet end of the water-use heat exchange component;

[0031] In the heat exchange area, the water flow in the water-using heat exchange component exchanges heat with the fourth heat exchange component to obtain the required hot water.

[0032] Further, the heat storage area includes a heat storage box and a heat storage module placed in the heat storage box, and the heat storage module includes a fifth heat exchange component and a second heat storage medium filled in the fifth heat exchange component;

[0033] The heat exchange area includes a heat exchange box, the heat exchange box is filled with a second heat exchange medium, the second heat exchange medium circulates between the heat storage box and the heat exchange box, the second heat exchange medium enters the heat storage box and exchanges heat with the second heat storage medium through the fifth heat exchange component;

[0034] The cold water pipe is connected with a water-use heat exchange component, which is placed in the heat exchange box and immersed in the second heat exchange medium;

[0035] The first outlet of the heat reflow zone is connected to the water-use heat exchange component and is connected to the liquid inlet end of the water-use heat exchange component;

[0036] In the heat exchange area, the water flow in the water heat exchange component exchanges heat with the second heat exchange medium to obtain the required hot water.

[0037] Furthermore, the electric water heater further comprises a liquid pump and a heating module, wherein a liquid inlet and a liquid outlet of the liquid pump are respectively connected to the heat exchange tank and the heat storage tank;

[0038] The heating module is arranged in the heat exchange box or the heat storage box; the second heat storage medium is a phase change material.

[0039] In summary, the electric hot water system with sewage heat recovery provided by the utility model has the following technical effects:

[0040] 1. By adding a sewage heat recovery device and a heat reflux area in the water heater, the sewage heat recovery device collects the heat in the sewage after use in the water heater and stores it in the heat reflux area. The water heater can utilize the heat in the heat reflux area to extend the water use time of the electric water heater.

[0041] 2. Add a heat reflow area in the water heater. The sewage heat recovery device collects the heat in the sewage after the water heater is used and stores it in the heat reflow area. The heat can be used when needed, or the heat can be temporarily stored in the heat reflow area. There are many working states and flexible choices.

[0042] 3. By adding a sewage heat recovery device and a heat reflux area in the water heater, the heat reflux area stores the standby water, and the sewage heat recovery device directly heats the standby water, which has a simple structure and good safety.

[0043] 4. The sewage filter device filters the sewage and has self-cleaning and flushing capabilities, which makes it easy to keep the sewage filter device clean and avoids frequent manual cleaning of the sewage filter device.

[0044] 5. The setting of heat storage area and heat exchange area in the water heater can reduce the amount of heated water in the water heater, avoid storing a large amount of hot water in the water heater after use, cause scale formation inside the water heater, affect the power and capacity loss of the water heater, and ensure a longer water use time. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic structural diagram of an embodiment of an electric hot water system with sewage heat recovery according to the technical solution of the utility model.

[0046] Figure 2 This is a schematic structural diagram of another embodiment of an electric hot water system with sewage heat recovery according to the technical solution of the utility model.

[0047] Figure 3 This is a structural schematic diagram of another embodiment of an electric hot water system with sewage heat recovery according to the technical solution of the utility model.

[0048] The meanings of the reference numerals are as follows:

[0049] 10. Electric water heater; 20. Sewage heat recovery device; 100. Cold water pipe;

[0050] 1. heat storage area; 11. first heat storage tank; 12. second heat storage tank; 13. first heating module; 14. second heating module; 15. first heat storage medium; 101. heat storage tank; 102. fifth heat exchange component; 103. second heat storage medium; 104. heating module;

[0051] 2. heat exchange area; 21. fourth heat exchange component; 22. water heat exchange component; 201. heat exchange box; 202. second heat exchange medium; 204. liquid pump;

[0052] 3. Heat reflow zone; 30. Preheated water; 301. Reflow tube; 31. First outlet; 32. Second outlet; 33. Second inlet; 34. First inlet;

[0053] 4. Sewage heat exchange mechanism; 40. Third heat exchange component; 41. Heat exchange insulation box; 42. Sewage coil; 43. Heat transfer medium; 44. Sewage;

[0054] 5. heat recovery mechanism; 50. first heat exchange medium; 51. first heat exchange component; 52. heat recovery pump; 53. second heat exchange component;

[0055] 6. Sewage filtering device; 61. Filter box; 62. Filter floor drain; 63. First filter mesh layer; 64. Second filter mesh layer; 65. Sewage outlet; 66. Sewage outlet; 67. Limit block; 68. Sewage inlet. DETAILED DESCRIPTION

[0056] For better understanding and implementation, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0057] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0059] See also Figures 1 to 3 , discloses a structural schematic diagram of an electric hot water system with sewage heat recovery according to the utility model.

[0060] An electric water heater system with sewage heat recovery includes an electric water heater 10 and a sewage heat recovery device 20. Generally, the electric water heater is installed on the wall and is located higher than the height of a standing human body, which is convenient for users to stand and take a shower, and is ergonomic, while the sewage heat exchange device 20 is installed under the bottom plate or on the ground, which is convenient for recycling and utilizing sewage.

[0061] In this solution, the electric water heater 10 includes a heat preservation explosion-proof housing of the water heater and a heat storage area 1, a heat exchange area 2 and a heat reflux area 3 placed in the heat preservation explosion-proof housing of the water heater, and the heat storage area 1, the heat exchange area 2 and the heat reflux area 3 are all independent of each other. The sewage heat recovery device 20 includes a sewage heat exchange mechanism 4 and a heat recovery mechanism 5, and the heat recovery mechanism 5 is connected to the heat reflux area 3. The heat recovery mechanism 5 exchanges heat with the sewage heat exchange mechanism 4 to obtain heat, and stores the heat in the heat reflux area 3, that is, the heat is stored in the electric water heater 10. The user can use the recovered heat according to needs, improve the heat utilization rate, and save energy.

[0062] In this solution, the overall concept is to recover and store the heat in the sewage, and then use it as needed. The heat stored in the heat reflux zone 3 of the electric water heater 10 by the heat recovery mechanism 5 can be used in time, or it can be temporarily stored for the next use, and the use or usage method is flexible. In this solution, by adding a sewage heat recovery device and storing the heat in the heat reflux zone 3 of the electric water heater 10 by the heat recovery mechanism 5, the water heater can utilize the heat in the heat reflux zone, extend the water use time of the electric water heater, especially extend the single water use time of the water heater, make up for the problem of insufficient water use time of the electric water heater in the prior art, and meet the requirements of people on the water use time of the electric water heater in the prior art.

[0063] In this solution, a water-using heat exchange component 22 connected to the cold water pipe is provided in the heat exchange area 2, and an inner transparent area for observing the flow of water in the water-using heat exchange component 22 is provided on the water-using heat exchange component 22. An outer transparent area is provided on the heat exchange area 2, and the outer transparent area faces the inner transparent area.

[0064] Relative outer transparent areas and inner transparent areas are respectively arranged on the heat exchange area 2 and the water-using heat exchange component 22 placed in the heat exchange area 2. The flow of water in the water-using heat exchange component can be observed through the two transparent areas, so that the user can clearly observe the flow and direction of the water in the water-using heat exchange component, realizing visual live water washing, clean and hygienic.

[0065] In order to facilitate the understanding of the sewage heat recovery device and the working process of the sewage heat recovery device in recovering heat from sewage, the sewage heat recovery device is introduced in detail below.

[0066] like Figure 1As shown, the heat reflow zone 3 has a reflow cylinder 301, on which a second inlet 33, a first outlet 31 and a second outlet 32 ​​are arranged; the first outlet 31 is connected to the heat exchange zone 2. The heat recovery mechanism 5 includes a first heat exchange device, which includes a first heat exchange component 51, and the two ends of the first heat exchange component 51 are respectively connected to the second inlet 33 and the second outlet 32. The first heat exchange component 51 exchanges heat with the sewage heat exchange mechanism 4, and reflows and stores the heat to the heat reflow zone 3.

[0067] In order to simplify the structure of the first heat exchange component 51, the first heat exchange component 51 can adopt a heat exchange coil or any heat exchange structure in the prior art that can meet the requirements of this scheme. When the first heat exchange component 51 is a heat exchange coil, it can be a single heat exchange coil or a plurality of heat exchange coils connected in parallel or in series. The heat exchange coil is made of a heat-conducting material and can be wound in a spiral shape, or in a reciprocating folding shape, or in a concentric circle shape, so as to maximize the contact area between the first heat exchange component 51 and the sewage heat exchange mechanism 4, so as to facilitate the heat exchange between the sewage heat exchange mechanism 4 and the first heat exchange component 51. The first heat exchange component 51 is filled with a heat storage medium or a heat conducting medium. The heat storage medium or the heat conducting medium in the first heat exchange component 51 absorbs the heat in the sewage through the sewage heat exchange mechanism 4, and then stores the heat in the heat reflux area 3 through the heat storage medium or the heat conducting medium in the first heat exchange component 51.

[0068] The heat storage medium or heat conducting medium in the first heat exchange component 51 enters the heat recirculation zone 3 through the second inlet 33, and then circulates back to the first heat exchange component 51 through the second outlet 32 ​​on the heat recirculation zone 3, and exchanges heat with the sewage heat exchange mechanism 4 again, thereby increasing the temperature of the heat storage medium or heat conducting medium in the first heat exchange component 51, or transporting the heat in the sewage to the heat recirculation zone and storing it through the heat storage medium or heat conducting medium in the first heat exchange component 51.

[0069] In one embodiment, the end of the first heat exchange component 51 connected to the second outlet 32 ​​is also connected to the cold water pipe 100. Figure 1 and Figure 2 Generally, the cold water pipe 100 is connected to the tap water pipe at the far end. When the heat recovery starts, the cold water in the tap water pipe enters the first heat exchange component 51. The cold water exchanges heat with the sewage heat exchange mechanism 4 in the first heat exchange component 51 to obtain preheated water 30. The so-called preheated water 30 is water with a higher temperature after the first heat exchange component 51 exchanges heat with the sewage heat exchange mechanism 4. The preheated water 30 in the first heat exchange component 51 flows back to the heat reflux area 3 through the second inlet 33. That is, through the process of converting cold water into preheated water, the heat in the sewage is recovered and stored in the heat reflux area 3.

[0070] In the above embodiment, in order to continuously recover the heat in the sewage and to increase the temperature of the preheated water in the heat reflux zone 3 as much as possible so that the preheated water stored in the heat reflux zone can meet the use temperature requirements, the preheated water in the heat reflux zone 3 can be circulated with the first heat exchange component 51 for multiple times, so that the same preheated water can exchange heat with the sewage multiple times to obtain the heat in the sewage, and the temperature of the preheated water increases. That is, when the temperature of the preheated water 30 in the heat reflux zone 3 is lower than the sewage heat exchange temperature threshold, the preheated water 30 in the heat reflux zone 3 enters the first heat exchange component 51 through the second outlet 32 ​​and exchanges heat with the sewage heat exchange mechanism 4 again.

[0071] The sewage heat exchange temperature threshold generally refers to the temperature of the sewage that is about to enter the sewage heat exchange mechanism 4 .

[0072] According to the living habits and washing habits of different users, as well as the changes in the external environment temperature, the sewage generated by some users has a lower temperature and carries less heat. After entering the sewage heat exchange mechanism 4, this part of the sewage exchanges heat with the cold water or preheated water in the first heat exchange component 51. The heat in the sewage obtained by the cold water or preheated water through the first heat exchange component 51 is too little, and the heat exchange is not meaningful, so heat exchange can be omitted. That is, when the temperature of the preheated water 30 in the heat reflux area 3 is lower than the sewage heat exchange temperature threshold, the preheated water 30 in the heat reflux area 3 is moved by the heat recovery pump 52, enters the first heat exchange component 51 through the second outlet 32, and exchanges heat with the sewage heat exchange mechanism 4 again.

[0073] Or after the preheated water has been heat exchanged for many times, the temperature of the preheated water entering the heat reflux zone 3 is relatively high. The preheated water with a relatively high temperature exchanges heat with the sewage again in the first heat exchange component 51, and the amount of heat that can be obtained is not high. At this time, the preheated water in the heat reflux zone 3 does not circulate and exchange heat with the first heat exchange component 51, but directly transports cold water to the first heat exchange component 51 through the cold water pipe for heat exchange. After the cold water is heat exchanged, it enters the heat reflux zone 3 again, reducing the temperature of the preheated water in the heat reflux zone 3, and the preheated water can circulate and exchange heat again. That is, when the temperature of the preheated water 30 in the heat reflux zone 3 is not lower than the threshold temperature of the sewage heat exchange, the cold water pipe 100 transports cold water to the first heat exchange component 51, and the cold water exchanges heat with the sewage heat exchange mechanism 4 in the first heat exchange component 51 to obtain the preheated water 30 again. The preheated water 30 flows back to the heat reflux zone 3 through the second inlet 33.

[0074] In the above embodiment, cold water is transported to the first heat exchange component 51 through a cold water pipe connected to the tap water pipe, and the cold water is heat exchanged to obtain preheated water, which is stored in the heat reflux area 3. The preheated water stored in the heat reflux area 3 can be directly used by the user. The preheated water in the heat reflux area 3 can flow out through the first outlet 31 and be used directly by the user, or be used after heat exchange and temperature increase in the heat exchange area 2 of the electric water heater 10. Because the preheated water has a higher temperature, less heat energy in the electric water heater 10 is consumed when heat is exchanged in the heat exchange area 2, which can extend the heat exchange time of the electric water heater and extend the water use time of the electric water heater.

[0075] That is, in the above embodiment, the preheated water is directly obtained by heat exchange through the sewage heat exchange mechanism 4 and the heat recovery mechanism 5, and is stored in the heat reflux area 3, and then waits for use. When the sewage heat exchange mechanism 4 and the heat recovery mechanism 5 exchange heat, the preheated water is obtained without consuming the heat of the electric water heater itself, and the heat storage area and heat exchange area in the electric water heater 10 do not participate in the work.

[0076] like Figure 3 As shown, another embodiment of the first heat exchange device is shown. In this embodiment, cold water is no longer directly input into the first heat exchange device. In order to further understand the structure and working process of the first heat exchange device of this embodiment, the first heat exchange device is specifically introduced below.

[0077] In this embodiment, the first heat exchange device includes not only the first heat exchange component 51, but also the second heat exchange component 53, and the second heat exchange component 53 is placed in the heat recirculation area 3 and the two ends are respectively connected to the first heat exchange component 51 through the second inlet 33 and the second outlet 32. The first heat exchange component 51 and the second heat exchange component 53 are filled with the first heat exchange medium 50, and the first heat exchange medium 50 circulates in the first heat exchange component 51 and the second heat exchange component 53 through the heat recovery pump 52.

[0078] During the circulation of the first heat exchange medium 50 , the first heat exchange medium 50 exchanges heat with the sewage heat exchange mechanism 4 in the first heat exchange component 51 , and the first heat exchange medium 50 stores heat in the heat reflux area 3 through the second heat exchange component 53 .

[0079] In this embodiment, the heat in the sewage is obtained by the first heat exchange medium 50, and the heat is stored in the heat recirculation zone 3. Specifically, a first inlet 34 may be provided on the heat recirculation zone 3, the first inlet 34 is connected to the cold water pipe 100, the cold water pipe 100 replenishes cold water into the heat recirculation zone 3, the second heat exchange component 53 is at least partially immersed in the cold water in the heat recirculation zone 3, and the cold water exchanges heat with the first heat exchange medium 50 in the second heat exchange component 53, that is, the heat of the sewage is recovered and stored in the heat recirculation zone 3.

[0080] In this embodiment, the sewage does not directly exchange heat with cold water, but exchanges heat through the first heat exchange medium 50 circulating in the first heat exchange component 51 and the second heat exchange component 53. In this heat exchange method, the first heat exchange medium 50 can be selected, and a heat exchange medium with good heat exchange capacity can be selected according to needs to improve the heat exchange effect and improve the heat recovery capacity in the sewage. In addition, the first heat exchange medium 50 circulates in the first heat exchange component 51 and the second heat exchange component 53, and the first heat exchange medium 50 will not be lost and is always retained in the first heat exchange component 51 and the second heat exchange component 53. At the beginning of the heat exchange, the first heat exchange medium 50 can circulate after the sewage is collected, and the heat recovery pump 52 can be delayed to start to reduce energy consumption.

[0081] In this embodiment, the first heat exchange medium 50 can be a heat conducting medium. The heat conducting medium includes but is not limited to tap water, purified water, heat conducting oil or heat conducting solution. The first heat exchange medium 50 is selected according to needs, with good flexibility and strong applicability. The first heat exchange medium 50 can also be a phase change material that can flow under low temperature conditions, and will exchange heat with the first heat exchange component 51, and will be stored in the heat reflux area 3 through the second heat exchange component 53.

[0082] In order to simplify the structure of the second heat exchange component 53, the second heat exchange component 53 can adopt a heat exchange coil or any heat exchange structure in the prior art that can meet the requirements of this scheme. When the second heat exchange component 53 is a heat exchange coil, it can be a single heat exchange coil or multiple heat exchange coils connected in parallel or in series. The heat exchange coil is made of a heat-conducting material and can be wound in a spiral shape, or in a reciprocating folding shape, or in a concentric circle shape, so as to maximize the contact area between the second heat exchange component 53 and the heat reflux zone, so as to facilitate the second heat exchange component 53 to exchange heat with the cold water or preheater in the heat reflux zone.

[0083] In order to facilitate those skilled in the art to further understand the sewage heat recovery device, the sewage heat exchange mechanism 4 is introduced in detail below.

[0084] like Figure 2 As shown, the sewage heat exchange mechanism 4 includes a third heat exchange component 40 that exchanges heat with the first heat exchange component 51. The third heat exchange component 40 includes a heat exchange insulation box 41 for collecting sewage with a temperature higher than the sewage heat exchange temperature threshold, and the first heat exchange component 51 is placed in the heat exchange insulation box 41 and immersed in the sewage, and the first heat exchange component 51 is in direct contact with the sewage and exchanges heat.

[0085] Sewage with a temperature higher than the sewage heat exchange temperature threshold enters the heat exchange insulation box 41, and the first heat exchange component 51 is fully or partially immersed in the sewage. The sewage exchanges heat with the cold water or preheated water 30 or the first heat exchange medium 50 in the first heat exchange component 51 through the first heat exchange component 51. The cold water or preheated water 30 or the first heat exchange medium 50 absorbs heat in the sewage and then circulates to the heat reflux area. The preheated water is stored in the heat reflux area 3, that is, the heat in the sewage is recovered and stored in the heat reflux area 3, or the first heat exchange medium 50 heats the cold water or preheated water in the heat reflux area 3 through the second heat exchange component to store the heat in the heat reflux area 3.

[0086] In this embodiment, heat exchange is achieved by immersing the first heat exchange component 51 in sewage, so that the sewage is in full contact with the first heat exchange component 51, thereby improving the heat exchange effect and maximizing the absorption of heat in the sewage.

[0087] like Figure 3 FIG. 4 is another embodiment of the sewage heat exchange mechanism 4. The sewage heat exchange mechanism 4 of this embodiment is described in detail below.

[0088] The sewage heat exchange mechanism 4 includes a third heat exchange component 40 that exchanges heat with the first heat exchange component 51. The third heat exchange component 40 includes a heat exchange insulation box 41 and a sewage coil 42 placed in the heat exchange insulation box 41. Sewage with a temperature higher than the sewage heat exchange temperature threshold enters the sewage coil 42, and the first heat exchange component 51 exchanges heat with the sewage coil 42.

[0089] In this embodiment, sewage is collected by adding a sewage coil 42, and the sewage in the sewage coil 42 exchanges heat with the first heat exchange component 51 to heat the cold water or preheated water or the first heat exchange medium in the first heat exchange component 51. By adding the sewage coil 42, direct contact between sewage and the first heat exchange component 51 is avoided, and dirt in the sewage is prevented from adhering to the first heat exchange component 51, thereby ensuring the heat exchange effect of the first heat exchange component 51.

[0090] In order to simplify the structure of the third heat exchange component 40, the third heat exchange component 40 can adopt a heat exchange coil or any heat exchange structure in the prior art that can meet the requirements of this solution. When the third heat exchange component 40 is a heat exchange coil, it can be a single heat exchange coil or multiple heat exchange coils connected in parallel or in series. The heat exchange coil is made of heat conductive material. The setting and selection of the structure of the third heat exchange component 40 ensures contact and heat exchange with the first heat exchange component 51 to the maximum extent.

[0091] In order to further enhance the heat exchange effect of the sewage heat exchange mechanism 4 and the first heat exchange component 51 in this embodiment, on the basis of the above-mentioned sewage heat exchange mechanism 4, a heat transfer medium 43 is filled in the heat exchange insulation box 41, such as Figure 1As shown. The heat transfer medium 43 fills the area between the first heat exchange component 51 and the sewage coil 42, so as to transfer the heat on the sewage coil 42 to the first heat exchange component 51 evenly and quickly. The heat transfer medium 43 can be heat transfer oil, heat transfer solution or heat transfer water or other solid heat transfer substances. The heat transfer medium 43 is enclosed in the heat exchange insulation box 41, and basically will not overflow or volatilize, and basically will not be lost, and has a long service life.

[0092] like Figures 1 to 3 As shown, the sewage heat exchange mechanism 4 also includes a sewage filter device 6 arranged in front of the third heat exchange component 40.

[0093] The sewage filtering device 6 comprises a filtering floor drain 62 and a filtering box 61 connected to the rear of the filtering floor drain 62. The filtering box 61 is provided with a sewage inlet 68, a sewage outlet 65 and a sewage outlet 66, the sewage inlet 68 is connected to the filtering floor drain 62, the sewage outlet 66 is connected to the third heat exchange component 40, and the sewage drainage is connected to the sewage pipe.

[0094] A first filter mesh layer 63 and a second filter mesh layer 64 are arranged in the filter box 61 . The first filter mesh layer 63 is placed below the second filter mesh layer 64 , and the mesh aperture of the first filter mesh layer 63 is smaller than the mesh aperture of the second filter mesh layer 64 .

[0095] The sewage outlet 65 is arranged at the bottom of the filter box 61 , the sewage outlet 66 is arranged at the top of the filter box 61 , and the sewage inlet 68 is arranged below the first filter mesh layer 63 and not close to the bottom of the filter box 61 .

[0096] The sewage generated when using water passes through the filter floor drain 62 and the sewage inlet 68 in sequence and enters the filter box 61. The sewage first enters the lower layer of the first filter mesh layer 63. The sewage first settles in the lower layer of the first filter mesh layer 63, and some heavy stains in the sewage are settled and stay on the bottom surface of the filter box 61. Then, as the amount of sewage increases, the sewage level in the filter box 61 rises. When the sewage passes through the first filter mesh layer 63, the larger floating objects in the sewage are intercepted and filtered by the first filter mesh layer 63. The sewage level of the first filter mesh layer 63 of the manhole cover continues to rise and contacts the second filter mesh layer 64. The second filter mesh layer 64 intercepts and filters the smaller stains or floating objects in the sewage. Finally, the sewage passes through the second filter mesh layer 64 and enters the heat exchange and insulation box 41 of the sewage heat exchange mechanism 4 through the sewage outlet 66 set at the top of the filter box 61, and exchanges heat with the heat recovery mechanism 5. The heat recovery mechanism 5 recovers the heat in the sewage.

[0097] After the sewage generated during water use enters the filter box 61, if the sewage temperature is higher than the sewage heat exchange temperature threshold, it enters the heat exchange insulation box 41 of the sewage heat exchange mechanism 4 through the sewage outlet 66 on the filter box 61 for heat exchange. If the sewage temperature is lower than the sewage heat exchange temperature threshold after entering the filter box 61, the sewage is directly discharged through the sewage outlet 65 on the filter box 61 without entering the heat exchange insulation box 41 of the sewage heat exchange mechanism 4 for heat exchange.

[0098] In order to facilitate the smooth discharge of sewage in the filter box 61, the bottom surface of the filter box 61 is set as an inclined bottom surface, and the sewage outlet 65 is set close to the lower end of the inclined bottom surface. The sewage in the filter box 61 is discharged through the sewage outlet 65, which can realize the emptying of the filter box 61, avoid the sewage from being retained in the filter box 61 for a long time, scaling in the filter box 61, and avoid the filter box 61 from stinking due to the long-term retention of sewage.

[0099] The first filter mesh layer 63 and the second filter mesh layer 64 in the filter box 61 can intercept the dirt in the sewage. The floating objects or garbage in the sewage are intercepted by the first filter mesh layer 63 and the second filter mesh layer 64 and stay below the first filter mesh layer 63 and the second filter mesh layer 64. When the sewage in the filter box 61 is emptied, it is hoped that the dirt in the filter box 61 and the intercepted floating garbage can be discharged at the same time. Therefore, in one embodiment, the first filter mesh layer 63 and the second filter mesh layer 64 are both light floating plates. The light floating plates rise and fall with the rise and fall of the water level in the filter box 61, so that the floating objects and garbage intercepted by the first filter mesh layer 63 and the second filter mesh layer 64 are immersed in the sewage and finally discharged together with the sewage, so as to avoid the accumulation of floating objects and garbage in the filter box 61.

[0100] In order to ensure that the first filter mesh layer 63 and the second filter mesh layer 64 are always located above the sewage inlet 68 and can always intercept floating garbage, a limit stopper 67 is fixed at the sewage inlet 68. When the water level in the filter box 61 drops, the first filter mesh layer 63 and the second filter mesh layer 64 drop with the water level, and the limit stopper 67 limits the lowest position of the first filter mesh layer 63.

[0101] In one embodiment, Figure 1 As shown, the heat storage area 1 includes a first heat storage tank 11 and a second heat storage tank 12 that are isolated from each other. A first heating module 13 and a second heating module 14 are respectively disposed in the first heat storage tank 11 and the second heat storage tank 12.

[0102] A fourth heat exchange component 21 is connected between the first heat storage tank 11 and the second heat storage tank 12 , and the fourth heat exchange component 21 is disposed in the heat exchange area 2 .

[0103] The first heat storage tank 11 or the second heat storage tank 12 is filled with the first heat storage medium 15 , and the first heat storage medium 15 circulates between the first heat storage tank 11 and the second heat storage tank 12 through the fourth heat exchange component 21 .

[0104] The first heating module 13 heats the first heat storage medium 15 in the first heat storage tank 11, and the heated first heat storage medium 15 enters the second heat storage tank 12 through the fourth heat exchange component 21. Alternatively, the second heating module 14 heats the first heat storage medium 15 in the second heat storage tank 12, and the heated first heat storage medium 15 enters the first heat storage tank 11 through the fourth heat exchange component 21.

[0105] The cold water pipe 100 is connected to a water heat exchange component 22 , and the water heat exchange component 22 is placed in the heat exchange area 2 .

[0106] The first outlet 31 of the heat recirculation zone 3 is connected to the water heat exchange component 22 , and is connected to the liquid inlet end of the water heat exchange component 22 .

[0107] In the heat exchange area 2, the water flow in the water heat exchange component 22 exchanges heat with the fourth heat exchange component 21 to obtain the required hot water.

[0108] In order to realize heat exchange in the heat exchange zone 2 and simplify the structure of the fourth heat exchange component 21 and the water heat exchange component 22, a structure of a heat exchange zone is provided below. The heat exchange zone 2 includes a water heat exchange insulation box, and the fourth heat exchange component 21 and the water heat exchange component 22 are both placed in the water heat exchange insulation box. The fourth heat exchange component 21 and the water heat exchange component 22 can be heat exchange coils respectively. In the water heat exchange insulation box, the two heat exchange coils are fully in contact to achieve heat exchange. Alternatively, one of the fourth heat exchange component 21 and the water heat exchange component 22 is a heat exchange coil. If the water heat exchange component 22 is a heat exchange coil, the fourth heat exchange component 21 is the water heat exchange insulation box itself and the liquid inlet and liquid outlet set on the water heat exchange insulation box. The first heat storage medium 15 enters the water heat exchange insulation box from the liquid inlet and fully contacts with the water heat exchange component 22 to achieve heat exchange with the water flow inside the water heat exchange component 22. After heat exchange, the first heat storage medium 15 is discharged from the liquid outlet.

[0109] Based on the above embodiment, one of the first heat storage tank 11 and the second heat storage tank 12 is a high temperature tank, in which the first heat storage medium 15 is heated, and then the heat is temporarily stored in the high temperature tank, that is, the high temperature tank is used for heat storage. The other is a low temperature tank, which is used to store the first heat storage medium 15 after heat exchange by the fourth heat exchange component 21. After all or most of the first heat storage medium 15 in the high temperature tank enters the low temperature tank, the first heat storage medium 15 is heated in the low temperature tank, and at this time the low temperature tank is converted into a high temperature tank, and the circulation route of the first heat storage medium 15 is opposite to the previous circulation route.

[0110] Based on the above embodiment, the first heat storage medium 15 only performs heat exchange and circulates between the first heat storage tank 11 and the second heat storage tank 12, and will not mix with cold water or water. The first heat storage medium 15 is a heat transfer medium, such as heat transfer oil, pure water, tap water, heat transfer solution, etc. The capacities of the first heat storage tank 11 and the second heat storage tank 12 are basically the same, and the amount of the first heat storage medium 15 only needs to fill the first heat storage tank 11 or the second heat storage tank 12. In this way, during the heat storage stage, it is only necessary to heat the first heat storage medium 15 in the first heat storage tank 11 or the second heat storage tank 12. If the first heat storage medium 15 is pure water, which contains few impurities, it circulates between the first heat storage tank 11 or the second heat storage tank 12 for a long time, and there will be no large amount of scale problems in the first heat storage tank 11 or the second heat storage tank 12, which can ensure the capacity and working efficiency of the first heat storage tank 11 or the second heat storage tank 12. If the first heat storage medium 15 is self-filled tap water, the tap water is only circulated in the first heat storage tank 11 or the second heat storage tank 12, and the amount of scale introduced is limited. And according to the working process and principle of the heat storage area and the heat exchange area in this embodiment, after each water use, only the first heat storage medium 15 in the first heat storage tank 11 or the second heat storage tank 12 is heated or retains heat, which effectively reduces the loss and waste of heat.

[0111] Based on the above embodiment, when the heat storage area is working, if the first heat storage medium 15 in the first heat storage tank 11 is heated first, after completion, the first heat storage medium 15 enters the heat exchange area, exchanges heat with the water heat exchange component 22 through the fourth heat exchange component 21, and then the first heat storage medium 15 enters the second heat storage tank 12. The temperature of the first heat storage medium 15 entering the second heat storage tank 12 is reduced. In order to ensure that the first heat storage medium 15 can quickly participate in the heat exchange work again and extend the water use time of the electric water heater in this embodiment, at this time, the second heating module 14 in the second heat storage tank 12 is synchronously turned on to heat the first heat storage medium 15 in the second heat storage tank 12, and the first heat storage medium 15 is heated. When the first heat storage medium 15 in the first heat storage tank 11 has basically flowed into the second heat storage tank 12, and the first heat storage medium 15 in the second heat storage tank 12 has also completed the temperature rise synchronously, at this time, the first heat storage medium 15 can circulate in reverse, from the second heat storage tank 12 to the first heat storage tank 11 through the fourth heat exchange component 21, and exchange heat with the water heat exchange component 22 in the fourth heat exchange component 21, and continue to heat the cold water transported to the water heat exchange component 22 through the cold water pipe 100, so that the cold water is heated up to obtain the desired warm water or hot water. Based on this working process, the electric water heater adopting this heat storage area and heat exchange area scheme has a longer water use time. In a longer water use time, the first heat storage medium 15 can be circulated multiple times to ensure a long water use time.

[0112] In addition, in order to further enhance and improve the user experience, so that the user can clearly feel the live water washing design of the water heater, the heat exchange area is set to be transparent or an outer transparent area is set on the heat exchange area, and the water heat exchange component 22 is also set to be transparent or an inner transparent area for observing the flow of water in the water heat exchange component is set on the water heat exchange component, and the outer transparent area faces the inner transparent area. In this way, when using water, the user can clearly observe that the water flowing through the water heat exchange component 22 is transported by the cold water pipe connected to the tap water pipe, and is not the water stored for a long time inside the electric water heater, realizing visual live water washing, clean and hygienic.

[0113] like Figure 2 , which is another embodiment structure of the heat storage area.

[0114] In this embodiment, the heat storage area 1 includes a heat storage box 101 and a heat storage module disposed in the heat storage box 101 . The heat storage module includes a fifth heat exchange component 102 and a second heat storage medium 103 filled in the fifth heat exchange component 102 .

[0115] The heat exchange area 2 includes a heat exchange box 201, which is filled with a second heat exchange medium 202. The second heat exchange medium 202 circulates between the heat storage box 101 and the heat exchange box 201. The second heat exchange medium 202 enters the heat storage box 101 and exchanges heat with the second heat storage medium 103 through the fifth heat exchange component 102.

[0116] The cold water pipe 100 is connected to a water heat exchange component 22 , which is placed in a heat exchange box 201 and immersed in the second heat exchange medium 202 .

[0117] The first outlet 31 of the heat recirculation zone 3 is connected to the water heat exchange component 22 , and is connected to the liquid inlet end of the water heat exchange component 22 .

[0118] In the heat exchange area 2, the water flow in the water heat exchange component 22 exchanges heat with the second heat exchange medium 202 to obtain the required hot water.

[0119] In the heat storage area, heat is stored in the second heat storage medium 103, and the second heat exchange medium 202 circulates between the heat storage box 101 and the heat exchange box 201 to obtain heat from the second heat storage medium 103 and transfer the heat to the heat exchange box 201. The water heat exchange component 22 in the heat exchange box 201 exchanges heat with the second heat exchange medium 202 in the heat exchange box 201 to obtain hot water.

[0120] In order to improve the heat exchange efficiency between the water heat exchange component 22 and the second heat exchange medium 202, the water heat exchange component 22 is set as a coil. In order to facilitate the visual live water washing, an outer transparent area is set on the heat exchange box 201, and the outer transparent area faces the water heat exchange component 22. At the same time, the water heat exchange component 22 is also provided with an inner transparent area, and the inner transparent area faces the outer transparent area. In this way, the user can observe the flow of water in the water heat exchange component 22 from the water heat exchange component 22, and can observe that the water flow in the water heat exchange component 22 is transported by the cold water pipe connected to the tap water pipe, which enhances the experience.

[0121] In order to facilitate the heating and circulation of the second heat exchange medium 202, a liquid pump 204 and a heating module 104 are also provided in the electric water heater 10. The liquid inlet and the liquid outlet of the liquid pump 204 are respectively connected to the heat exchange box 201 and the heat storage box 101. When the liquid pump 204 works, it drives the second heat exchange medium 202 to circulate between the heat storage box 101 and the heat exchange box 201. The heating module 104 heats the second heat exchange medium 202, and the second heat exchange medium 202 is heated up and heat is exchanged with the second heat storage medium 103, so that the heat is stored in the second heat storage medium, that is, the heat is stored in the heat storage area.

[0122] In this way, the heating module 104 can be arranged in the heat exchange box 201 or the heat storage box 101. Figure 2 and Figure 3 After the heating module 104 is arranged in the heat exchange box 201, after the heat in the second heat storage medium 103 is exhausted, the second heat exchange medium 202 stops circulating and remains in the heat exchange box 201. The heating module 104 in the heat exchange box 201 directly heats the second heat exchange medium 202 in the heat exchange box 201, and then the second heat exchange medium 202 directly exchanges heat with the water heat exchange component 22, and the required hot water is obtained by increasing the temperature of the water flow in the water heat exchange component.

[0123] In the above embodiment, the second heat storage medium 103 is a phase change material, which is used to exchange heat with the second heat exchange medium 202 and store heat.

[0124] The technical means disclosed in the solution of the utility model are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical solutions composed of any combination of the above technical features. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model, and these improvements and modifications are also regarded as the protection scope of the utility model.

Claims

1. An electric hot water system with sewage heat recovery, characterized in that: It includes an electric water heater and a sewage heat recovery device; the electric water heater includes a heat storage area, a heat exchange area and a heat reflux area; the sewage heat recovery device includes a sewage heat exchange mechanism and a heat recovery mechanism, the heat recovery mechanism is connected to the heat reflux area, and stores heat in the heat reflux area.

2. The electric hot water system with sewage heat recovery according to claim 1, characterized in that: The heat reflow zone is provided with a second inlet, a first outlet and a second outlet; the first outlet is connected to the heat exchange zone; The heat recovery mechanism includes a first heat exchange device, which includes a first heat exchange component, and the two ends of the first heat exchange component are respectively connected to the second inlet and the second outlet; the first heat exchange component exchanges heat with the sewage heat exchange mechanism, and refluxes and stores heat in the heat reflux area.

3. The electric hot water system with sewage heat recovery according to claim 2, characterized in that: The end of the first heat exchange component connected to the second outlet is also connected to a cold water pipe, and the cold water exchanges heat with the sewage heat exchange mechanism in the first heat exchange component to obtain preheated water, and the preheated water flows back to the heat reflux area through the second inlet; When the temperature of the preheated water in the heat recirculation zone is lower than the sewage heat exchange temperature threshold, the preheated water in the heat recirculation zone enters the first heat exchange component through the second outlet and exchanges heat with the sewage heat exchange mechanism; When the temperature of the preheated water in the heat reflux zone is not lower than the sewage heat exchange threshold temperature, the cold water pipe transports cold water into the first heat exchange component, the cold water exchanges heat with the sewage heat exchange mechanism in the first heat exchange component to obtain preheated water again, and the preheated water flows back to the heat reflux zone through the second inlet.

4. The electric hot water system with sewage heat recovery according to claim 2, characterized in that: The first heat exchange device further includes a second heat exchange component, which is placed in the heat recirculation zone and has two ends connected to the first heat exchange component through the second inlet and the second outlet respectively; The first heat exchange component and the second heat exchange component are filled with a first heat exchange medium, and the first heat exchange medium circulates in the first heat exchange component and the second heat exchange component; The first heat exchange medium exchanges heat with the sewage heat exchange mechanism in the first heat exchange component, and the first heat exchange medium stores heat in the heat reflux area through the second heat exchange component.

5. The electric hot water system with sewage heat recovery according to claim 4, characterized in that: The heat reflow zone is provided with a first inlet, the first inlet is connected to a cold water pipe, the cold water pipe replenishes cold water into the heat reflow zone, and the cold water exchanges heat with the first heat exchange medium in the second heat exchange component.

6. The electric hot water system with sewage heat recovery according to claim 2, characterized in that: The sewage heat exchange mechanism includes a third heat exchange component for exchanging heat with the first heat exchange component; The third heat exchange component includes a heat exchange insulation box for collecting sewage with a temperature higher than the sewage heat exchange temperature threshold. The first heat exchange component is placed in the heat exchange insulation box and immersed in the sewage. The first heat exchange component directly contacts and exchanges heat with the sewage.

7. The electric hot water system with sewage heat recovery according to claim 2, characterized in that: The sewage heat exchange mechanism includes a third heat exchange component for exchanging heat with the first heat exchange component; The third heat exchange component includes a heat exchange insulation box and a sewage coil placed in the heat exchange insulation box. Sewage with a temperature higher than the sewage heat exchange temperature threshold enters the sewage coil, and the first heat exchange component exchanges heat with the sewage coil.

8. The electric hot water system with sewage heat recovery according to claim 6 or 7, characterized in that: The sewage heat exchange mechanism also includes a sewage filter device arranged in front of the third heat exchange component, the sewage filter device includes a filter floor drain and a filter box connected to the rear of the filter floor drain, the filter box is provided with a sewage inlet, a sewage outlet and a sewage outlet, the sewage inlet is connected to the filter floor drain, the sewage outlet is connected to the third heat exchange component, and the sewage drainage is connected to the sewage pipe; The filter box is provided with a first filter mesh layer and a second filter mesh layer, the first filter mesh layer is placed below the second filter mesh layer, and the mesh aperture of the first filter mesh layer is smaller than the mesh aperture of the second filter mesh layer; The sewage outlet is arranged at the bottom of the filter box, the sewage outlet is arranged at the top of the filter box, and the sewage inlet is arranged below the first filter screen layer and not close to the bottom of the filter box; The first filter mesh layer and the second filter mesh layer are both lightweight floating plates, and a limit block is fixedly provided at the sewage inlet position. When the water level in the filter box drops, the first filter mesh layer and the second filter mesh layer drop with the water level, and the limit block limits the lowest position of the first filter mesh layer.

9. The electric hot water system with sewage heat recovery according to claim 2, characterized in that: The heat storage area comprises a first heat storage tank and a second heat storage tank isolated from each other, wherein the first heat storage tank and the second heat storage tank are respectively provided with a first heating module and a second heating module; A fourth heat exchange component is connected between the first heat storage tank and the second heat storage tank, and the fourth heat exchange component is arranged in the heat exchange area; The first heat storage tank or the second heat storage tank is filled with a first heat storage medium, and the first heat storage medium circulates between the first heat storage tank and the second heat storage tank through the fourth heat exchange component; The first heating module heats the first heat storage medium in the first heat storage tank, and the heated first heat storage medium enters the second heat storage tank through the fourth heat exchange component; or, the second heating module heats the first heat storage medium in the second heat storage tank, and the heated first heat storage medium enters the first heat storage tank through the fourth heat exchange component; The cold water pipe is connected with a water-use heat exchange component, and the water-use heat exchange component is placed in the heat exchange area; The first outlet of the heat reflow zone is connected to the water-use heat exchange component and is connected to the liquid inlet end of the water-use heat exchange component; In the heat exchange area, the water flow in the water-using heat exchange component exchanges heat with the fourth heat exchange component to obtain the required hot water.

10. The electric hot water system with sewage heat recovery according to claim 2, characterized in that: The heat storage area includes a heat storage box and a heat storage module placed in the heat storage box, and the heat storage module includes a fifth heat exchange component and a second heat storage medium filled in the fifth heat exchange component; The heat exchange area includes a heat exchange box, the heat exchange box is filled with a second heat exchange medium, the second heat exchange medium circulates between the heat storage box and the heat exchange box, the second heat exchange medium enters the heat storage box and exchanges heat with the second heat storage medium through the fifth heat exchange component; The cold water pipe is connected with a water-use heat exchange component, which is placed in the heat exchange box and immersed in the second heat exchange medium; The first outlet of the heat reflow zone is connected to the water-use heat exchange component and is connected to the liquid inlet end of the water-use heat exchange component; In the heat exchange area, the water flow in the water heat exchange component exchanges heat with the second heat exchange medium to obtain the required hot water; The electric water heater further comprises a liquid pump and a heating module, wherein a liquid inlet and a liquid outlet of the liquid pump are respectively connected to the heat exchange tank and the heat storage tank; The heating module is arranged in the heat exchange box or the heat storage box; the second heat storage medium is a phase change material.

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