CN221005213U - Hot water supply system - Google Patents

Abstract

The utility model provides a hot water supply system, which comprises a solar water heater, a gas water heater and a first switching valve, wherein the solar water heater is provided with a first inlet and a first outlet, the first outlet is connected with a hot water main pipe, the gas water heater is provided with a second inlet and a second outlet, the second outlet is connected with the hot water main pipe, the first switching valve is provided with a third inlet, a third outlet and a fourth outlet, the third inlet is connected with the first outlet, the third outlet is connected with the second inlet, the fourth outlet is connected with the hot water main pipe, and the first switching valve is configured to: communicating the third inlet with the third outlet to heat hot water from the solar water heater using the gas water heater and then supplying the hot water to the hot water main; or the third inlet is communicated with the fourth outlet so that the hot water flowing out of the solar water heater is directly supplied to the hot water main pipe. The utility model can fully utilize clean energy, reduce the consumption of natural gas and shorten the response time of hot water.

Description

Hot water supply system

Technical Field

The utility model relates to the technical field of domestic water equipment, in particular to a hot water supply system.

Background

In order to reduce carbon emission, energy conservation and emission reduction are increasingly focused, efficient energy utilization is also urgent, and multi-energy combined heat supply is increasingly popular. The solar energy and the gas water heater are combined to provide hot water, so that the running cost of household daily water can be reduced, the water supply is stable and comfortable, and the energy utilization advantages of solar energy and gas are fully exerted.

In the existing solar water heater and gas water heater multi-energy combination system, when the water temperature in the solar water heater cannot meet the user requirement, the water temperature is directly switched to the gas water heater, the heat of the solar water heater can be wasted, clean energy cannot be fully utilized, and therefore improvement is necessary.

Disclosure of utility model

It is an object of the present utility model to overcome at least one of the drawbacks of the prior art by providing a hot water supply system combining a solar water heater and a gas water heater.

A further object of the present utility model is to fully utilize clean energy, reduce natural gas usage, and reduce hot water response time.

Another further object of the present utility model is to prevent the water temperature of the gas water heater from being too high to cause safety accidents.

In particular, the present utility model provides a hot water supply system comprising: a solar water heater having a first inlet and a first outlet, the first outlet being connected to the hot water main so as to supply hot water to each of the water units connected to the hot water main; a gas water heater having a second inlet and a second outlet, the second outlet being connected to the hot water main so as to supply hot water to each water unit connected to the hot water main; a first switching valve having a third inlet, a third outlet, and a fourth outlet, the third inlet connected to the first outlet, the third outlet connected to the second inlet, the fourth outlet connected to the hot water main, and the first switching valve configured to: communicating the third inlet with the third outlet to heat hot water from the solar water heater using the gas water heater and then supplying the hot water to the hot water main; or the third inlet is communicated with the fourth outlet so that the hot water flowing out of the solar water heater is directly supplied to the hot water main pipe.

Optionally, the hot water supply system further comprises: the second switching valve is arranged on a pipeline from the third outlet to the second inlet and is provided with a fourth inlet, a fifth inlet and a fifth outlet, the fourth inlet is connected with the third outlet, the fifth outlet is connected with the second inlet, the fifth inlet is connected with the cold water mother pipe, and the second switching valve is configured to: communicating the fourth inlet with the fifth outlet to pass hot water from the solar water heater to the gas water heater; or the fifth inlet is communicated with the fifth outlet so as to lead cold water from the cold water main pipe into the gas water heater.

Optionally, the hot water supply system further comprises: the first one-way valve is arranged on the pipeline from the cold water main pipe to the fifth inlet to prevent water in the gas water heater from flowing backwards to the cold water main pipe.

Optionally, the hot water supply system further comprises: the first temperature sensor is arranged in the solar water heater and is used for detecting the water temperature of the solar water heater; and the controller is electrically connected with the first temperature sensor, the first switching valve and the second switching valve so as to control and switch the flow path of the first switching valve and the flow path of the second switching valve according to the water temperature of the solar water heater.

Optionally, the hot water supply system further comprises: the second temperature sensor is arranged in the gas water heater and is used for detecting the water temperature of the gas water heater; the controller is electrically connected with the second temperature sensor so as to control and switch the flow path of the first switching valve and the flow path of the second switching valve according to the water temperature of the gas water heater.

Optionally, the solar water heater further comprises: the solar heat collector is used for converting solar radiation energy into heat energy; a water storage tank having a heat exchange coil therein; and the circulating water loop is used for connecting the heat exchange coil and the solar heat collector so as to transfer heat energy to the heat exchange coil through circulating water, and further the heat exchange coil is convenient to heat water in the water storage tank.

Optionally, the solar water heater further comprises: the circulating water pump is arranged in the circulating water loop so as to promote the circulating water to flow; and the controller is also electrically connected with the circulating water pump so as to control the starting and stopping of the circulating water pump according to the water temperature of the water storage tank.

Optionally, the first inlet is connected with a cold water main; and the hot water supply system further comprises: the second one-way valve is arranged on a pipeline from the cold water main pipe to the first inlet so as to prevent water in the solar water heater from flowing back to the cold water main pipe.

Optionally, the hot water supply system further comprises: the first stop valve is arranged on a pipeline from the second outlet to the hot water main pipe.

Optionally, the hot water supply system further comprises: the second stop valve is arranged on a pipeline from the fourth outlet to the hot water main pipe.

According to the hot water supply system, the solar water heater is provided with the first inlet and the first outlet, the gas water heater is provided with the second inlet and the second outlet, the first switching valve is provided with the third inlet, the third outlet and the fourth outlet, the third inlet is connected with the first outlet, the third outlet is connected with the second inlet, the fourth outlet is connected with the hot water main pipe, and when the third inlet is communicated with the third outlet, hot water from the solar water heater can enter the gas water heater through the first outlet, the third inlet, the third outlet and the second inlet, so that the hot water from the solar water heater can be heated by the gas water heater, and then is supplied to the hot water main pipe through the second outlet. In addition, although the water temperature led to the gas water heater by the solar water heater does not reach the target temperature, the temperature is higher than the water temperature of the cold water main pipe, so that the supply mode can shorten the response time of hot water and improve the use experience of a user.

Further, in the hot water supply system of the present utility model, the second switching valve is disposed on a line from the third outlet to the second inlet, and has a fourth inlet, a fifth inlet, and a fifth outlet, the fourth inlet is connected to the third outlet, the fifth outlet is connected to the second inlet, the fifth inlet is connected to the cold water pipe, and when the fifth inlet is connected to the fifth outlet, cold water from the cold water pipe is introduced into the gas water heater. The purpose of this section of tubing is two: firstly, cool the gas water heater by means of the cold water main pipe so as to control the water temperature of the gas water heater and avoid safety accidents caused by overhigh water temperature introduced into the gas water heater. And secondly, the solar water heater is used for isolating the solar water heater, and the gas water heater is directly used for heating cold water from the cold water main pipe.

The above, as well as additional objectives, advantages, and features of the present utility model will become apparent to those skilled in the art from the following detailed description of a specific embodiment of the present utility model when read in conjunction with the accompanying drawings.

Drawings

Some specific embodiments of the utility model will be described in detail hereinafter by way of example and not by way of limitation with reference to the accompanying drawings. The same reference numbers will be used throughout the drawings to refer to the same or like parts or portions. It will be appreciated by those skilled in the art that the drawings are not necessarily drawn to scale. In the accompanying drawings:

Fig. 1 is a schematic view of a hot water supply system according to an embodiment of the present utility model.

Detailed Description

In the description of the present utility model, a description of the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present utility model and simplify the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present utility model.

The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature, i.e. one or more such features. In the description of the present utility model, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise. When a feature "comprises or includes" a feature or some of its coverage, this indicates that other features are not excluded and may further include other features, unless expressly stated otherwise.

Unless specifically stated or limited otherwise, the terms "mounted," "connected," "secured," "coupled," and the like should be construed broadly, as they may be fixed, removable, or integral, for example; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. Those of ordinary skill in the art will understand the specific meaning of the terms described above in the present utility model as the case may be.

Furthermore, in the description of the present embodiments, a first feature "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature therebetween. That is, in the description of the present embodiment, the first feature being "above", "over" and "upper" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature "under", "beneath", or "under" a second feature may be a first feature directly under or diagonally under the second feature, or simply indicate that the first feature is less level than the second feature.

The working principle of the present utility model is described below with reference to fig. 1. Fig. 1 is a schematic view of a hot water supply system 1 according to one embodiment of the utility model.

The utility model provides a hot water supply system 1, wherein the hot water supply system 1 can comprise a solar water heater 100 and a gas water heater 200, namely the hot water supply system 1 is a multi-energy system formed by the solar water heater 100 and the gas water heater 200, the hot water supply system 1 can fully utilize solar energy, the water consumption cost is reduced, and the gas water heater 200 can also ensure the reliability of hot water supply.

In particular, the solar water heater 100 may include a solar collector 110, a storage tank 120, and a circulating water loop 140.

The solar collector 110 is placed outdoors to absorb solar radiation and convert it into heat energy. The water storage tank 120 is used for storing water, and has a first inlet 122 and a first outlet 124, the first inlet 122 may be connected to the cold water master 810 so as to supplement the water source to the water storage tank 120, and the first outlet 124 may be connected to the hot water master 820 so as to individually supply hot water to each of the water units 900 connected to the hot water master 820. The heat exchange coil 130 is further disposed in the water storage tank 120, and the circulating water loop 140 is used for connecting the heat exchange coil 130 and the solar heat collector 110, so that heat energy collected by the solar heat collector 110 is transferred to the heat exchange coil 130 through circulating water, and the heat exchange coil 130 is further convenient for heating water in the water storage tank 120. In addition, the solar water heater 100 may further include a circulating water pump 150, where the circulating water pump 150 is disposed in the circulating water loop 140 to promote the circulating water to flow, so as to improve the heat exchange efficiency.

The gas water heater 200 may include a water storage tank for storing water and a heating unit for heating the water storage tank. The water storage bladder has a second inlet 210 and a second outlet 220, the second inlet 210 being connectable to the main pipe 810 for supplementing the water supply to the water storage tank 120, and the first outlet 124 being connectable to the main pipe 820 for individually supplying hot water to each of the water units 900 connected to the main pipe 820. The heating unit is a gas unit, i.e. the water storage liner is heated by burning natural gas, and is not described in detail herein since it is not the point of the utility model herein.

Further, the hot water supply system 1 may further comprise a first switching valve 300, the first switching valve 300 having a third inlet 310, a third outlet 320 and a fourth outlet 330, i.e. the first switching valve 300 may be a three-way valve. The third inlet 310 is connected to the first outlet 124, the third outlet 320 is connected to the second inlet 210, and the fourth outlet 330 is connected to the hot water header 820.

The first switching valve 300 can communicate the third inlet 310 with the third outlet 320 or the third inlet 310 with the fourth outlet 330 by changing the position of the spool therein.

When the third inlet 310 is communicated with the third outlet 320, hot water from the solar water heater 100 may enter the gas water heater 200 through the first outlet 124, the third inlet 310, the third outlet 320, and the second inlet 210, so that the hot water from the solar water heater 100 is heated by the gas water heater 200 and then supplied to the hot water header 820 through the second outlet 220.

When the third inlet 310 is in communication with the fourth outlet 330, hot water from the solar water heater 100 may flow directly into the hot water header 820 from the first outlet 124, the third inlet 310, and the fourth outlet 330.

As can be seen, in the hot water supply system 1 of the present embodiment, the solar water heater 100 is led to the hot water main 820 in two ways, the first is directly led to the hot water main 820, and the second is flowing into the hot water main 820 again via the gas water heater 200.

The first case may be suitable for environments with abundant sunlight (e.g., summer, daytime, etc.), where solar water heater 100 is able to collect enough heat to fully heat the water in storage tank 120 to the target temperature. When the user uses hot water in this case, the first switching valve 300 is switched to communicate the third inlet 310 with the fourth outlet 330, and the hot water is supplied from the solar water heater 100 in its entirety.

The second case may be suitable for environments where solar conditions are poor (e.g., winter, night, etc.), where solar water heater 100 may not be able to heat the water of storage tank 120 to a target temperature despite some heat being collected. When the user uses hot water in this case, the first switching valve 300 is switched to communicate the third inlet 310 with the third outlet 320, hot water in the solar water heater 100 is discharged to the gas water heater 200 first, and the gas water heater 200 heats the hot water to a target temperature again and then supplies the hot water to the hot water main 820.

It can be seen that, in the second case, the hot water supply system 1 of the present embodiment does not directly supply hot water from the gas water heater 200, but uses the gas water heater 200 as an auxiliary heating means, and fully uses the heat collected by the solar water heater 100, thereby reducing the usage amount of natural gas. In addition, although the temperature of the water passing from the solar water heater 100 to the gas water heater 200 does not reach the target temperature, the temperature is still higher than the temperature of the water in the cold water pipe 810, so that the supply method can shorten the response time of the hot water and improve the user experience.

In some embodiments, the hot water supply system 1 may further include a second switching valve 400, where the second switching valve 400 is disposed on a line from the third outlet 320 to the second inlet 210, and has a fourth inlet 410, a fifth inlet 420, and a fifth outlet 430, where the fourth inlet 410 is connected to the third outlet 320, the fifth outlet 430 is connected to the second inlet 210, and the fifth inlet 420 is connected to the cold water pipe 810.

The second switching valve 400 can communicate the fourth inlet 410 with the fifth outlet 430 or the fifth inlet 420 with the fifth outlet 430 by changing the position of the spool therein.

When the fourth inlet 410 communicates with the fifth outlet 430, hot water from the solar water heater 100 is passed to the gas water heater 200. Specifically, when the first switching valve 300 is switched to communicate the third inlet 310 with the fourth outlet 330 and the second switching valve 400 is switched to communicate the fourth inlet 410 with the fifth outlet 430, hot water from the solar water heater 100 may enter the gas water heater 200 through the first outlet 124, the third inlet 310, the third outlet 320, the fourth inlet 410, the fifth outlet 430, and the second inlet 210.

When the fifth inlet 420 communicates with the fifth outlet 430, cold water from the cold water jellyfish pipe 810 is introduced into the gas water heater 200. The purpose of this section of tubing is two: firstly, the cold water of the cold water main pipe 810 is used for cooling the gas water heater 200 so as to control the water temperature of the gas water heater 200, and the safety accident caused by the overhigh water temperature of the gas water heater 200 is avoided. Secondly, the solar water heater 100 is used for isolating the solar water heater 100, and cold water from the cold water main 810 is directly heated by the gas water heater 200, specifically, when the first switching valve 300 is switched to close the third inlet 310 and the second switching valve 400 is switched to communicate the fifth inlet 420 with the fifth outlet 430, so that hot water of the solar water heater 100 cannot be discharged to the hot water main 820 or the gas water heater 200, and cold water in the cold water main 810 can flow to the gas water heater 200 through the fifth inlet 420 and the fifth outlet 430.

Further, the hot water supply system 1 may further include a first check valve 510, and the first check valve 510 may be disposed on the lines of the cold water pipe 810 to the fifth inlet 420 to prevent the water in the gas water heater 200 from flowing backward to the cold water pipe 810.

The kind of the first check valve 510 can be flexibly selected according to practical situations, such as a spring check valve, a gravity check valve, etc.

In some embodiments, the first switching valve 300 and the second switching valve 400 may be configured as solenoid three-way valves, so as to be controlled by the controller 600 according to actual situations.

Specifically, the hot water supply system 1 may further include a first temperature sensor 610 and a controller 600. The first temperature sensor 610 is disposed in the solar water heater 100, specifically, may be disposed in the water tank 120 to detect the water temperature of the solar water heater 100.

The controller 600 is electrically connected to the first temperature sensor 610, the first switching valve 300, and the second switching valve 400 so as to control switching of the flow path of the first switching valve 300 and the flow path of the second switching valve 400 according to the water temperature of the solar water heater 100.

As can be seen from the above analysis, when the solar water heater 100 is capable of heating the water in the water storage tank 120 to the target temperature, the first switching valve 300 is switched to communicate the third inlet 310 with the fourth outlet 330, and all the hot water is supplied from the solar water heater 100, and when the solar water heater 100 is not capable of heating the water in the water storage tank 120 to the target temperature, the first switching valve 300 is switched to communicate the third inlet 310 with the third outlet 320, and the second switching valve 400 is switched to communicate the fourth inlet 410 with the fifth outlet 430, so that the hot water of the solar water heater 100 is discharged into the gas water heater 200 first, and the gas water heater 200 heats the hot water for the second time to reach the target temperature. Accordingly, the logic of the controller 600 controlling the first switching valve 300 and the second switching valve 400 may employ the above-described principle.

For example, the controller 600 obtains the current water temperature of the solar water heater 100 detected by the first temperature sensor 610, and compares the current water temperature with the target temperature set by the user.

When the current water temperature is not lower than the target temperature or the temperature difference between the current water temperature and the target temperature is not large, the controller 600 sends a command to the execution unit 340 of the first switching valve 300 to switch to communicate the third inlet 310 with the fourth outlet 330, and the hot water is supplied from the solar water heater 100 entirely.

When the current water temperature is less than the target temperature or the temperature difference between the current water temperature and the target temperature is large, the controller 600 sends an instruction to the execution unit 340 of the first switching valve 300 to switch to communicate the third inlet 310 and the third outlet 320, and sends an instruction to the execution unit 440 of the second switching valve 400 to switch to communicate the fourth inlet 410 and the fifth outlet 430, so that the hot water of the solar water heater 100 is discharged into the gas water heater 200 first.

Further, the hot water supply system 1 may further include a second temperature sensor 620, where the second temperature sensor 620 is disposed in the gas water heater 200, and in particular may be disposed in the water storage liner, for detecting the water temperature of the gas water heater 200.

The controller 600 may also be electrically connected to the second temperature sensor 620 to switch the flow path of the first switching valve 300 and the flow path of the second switching valve 400 according to the water temperature control of the gas water heater 200.

From the above analysis, it is known that one purpose of the second switching valve 400 is to avoid safety accidents caused by too high water temperature of the gas water heater 200, so that the controller 600 can follow the logic when controlling the second switching valve 400, and the priority is set to be highest.

For example, the controller 600 may record a temperature threshold (e.g., 50 degrees celsius), and the controller 600 obtains the current water temperature of the gas water heater 200 detected by the second temperature sensor 620, and compares the current water temperature with the temperature threshold. When the current water temperature is higher than the temperature threshold, the controller 600 sends an instruction to the execution unit 340 of the first switching valve 300 to close the third inlet 310, and sends an instruction to the execution unit 440 of the second switching valve 400 to switch to communicate the fifth inlet 420 and the fifth outlet 430, and cold water of the cold water pipe 810 is introduced to cool the gas water heater 200, thereby avoiding accidents.

In addition, the controller 600 may be electrically connected to the circulating water pump 150 of the solar water heater 100 to control the circulating water pump 150 to start and stop according to the water temperature of the water tank 120, so that the water temperature in the solar water heater 100 is always kept within a reasonable temperature range.

Specifically, the hot water supply system 1 may further include a third temperature sensor 630, where the third temperature sensor 630 is disposed in the circulating water circuit 140 for detecting the temperature of the circulating water.

The controller 600 acquires the current water temperature of the water storage tank 120 detected by the first temperature sensor 610 and the current water temperature of the circulating water detected by the third temperature sensor 630.

When the temperature difference between the current water temperature of the water storage tank 120 and the current water temperature of the circulating water is greater than a first preset temperature threshold (for example, 8 degrees celsius), the controller 600 sends a start command to the circulating water pump 150 to improve the heat exchange efficiency, so as to promote the current water temperature of the water storage tank 120 to reach a reasonable range as soon as possible.

When the temperature difference between the current water temperature of the water storage tank 120 and the current water temperature of the circulating water is less than a second preset temperature threshold (the second preset temperature threshold is less than the first preset temperature threshold, for example, 2 degrees celsius), the controller 600 sends an outage instruction to the circulating water pump 150.

Further, the hot water supply system 1 may further include a second check valve 520, wherein the second check valve 520 is disposed on a line from the cold water pipe 810 to the first inlet 122 to prevent water in the solar water heater 100 from flowing back to the cold water pipe 810.

The type of the second check valve 520 can be flexibly selected according to practical situations, such as a spring check valve, a gravity check valve, etc.

Further, the hot water supply system 1 may further include a first shut-off valve 710, the first shut-off valve 710 being disposed on a line from the second outlet 220 to the hot water supply pipe 820.

The first shut-off valve 710 may be provided as a solenoid valve so as to be controlled by the controller 600. For example, when the gas water heater 200 participates in heating, the first shut-off valve 710 is controlled to be opened. When the gas water heater 200 is not involved in heating (e.g., the solar water heater 100 is used to supply hot water), the first shut-off valve 710 is controlled to be closed.

The hot water supply system 1 may further include a second shut-off valve 720, the second shut-off valve 720 being disposed on a line from the fourth outlet 330 to the hot water master 820.

The second shut-off valve 720 may also be provided as a solenoid valve to be controlled by the controller 600. For example, when the user uses hot water, the second shut-off valve 720 is controlled to be opened, and when water use is stopped, the second shut-off valve 720 is controlled to be closed.

The working principle of the utility model can be summarized as follows:

When the solar water heater 100 cannot provide the water heat, the controller 600 controls the first switching valve 300 to switch to communicate the third inlet 310 with the fourth outlet 330, and controls the second switching valve 400 to switch to communicate the fourth inlet 410 with the fifth outlet 430, so that the hot water from the solar water heater 100 can enter the gas water heater 200 through the first outlet 124, the third inlet 310, the third outlet 320, the fourth inlet 410, the fifth outlet 430 and the second inlet 210, and the gas water heater 200 heats the hot water again to reach the target temperature, and then is supplied to the hot water main 820 through the first stop valve 710, and then is supplied to the water unit 900, thereby saving natural gas and shortening the hot water response time.

In this state, the controller 600 acquires the current water temperature of the gas water heater 200 detected by the second temperature sensor 620, and when the current water temperature is higher than the temperature threshold value, the controller 600 sends an instruction to the execution unit 340 of the first switching valve 300 to close the third inlet 310, and sends an instruction to the execution unit 440 of the second switching valve 400 to switch to communicate the fifth inlet 420 and the fifth outlet 430, and cold water of the cold water pipe 810 is introduced to cool the gas water heater 200, thereby avoiding an accident.

When the solar water heater 100 is capable of providing water heat, the controller 600 controls the first switching valve 300 to switch to communicate the third inlet 310 with the fourth outlet 330, so that the hot water from the solar water heater 100 can directly flow into the hot water mother pipe 820 from the first outlet 124, the third inlet 310, the fourth outlet 330, and the second shut-off valve 720, i.e., all of the hot water is provided by the solar water heater 100.

By now it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the utility model have been shown and described herein in detail, many other variations or modifications of the utility model consistent with the principles of the utility model may be directly ascertained or inferred from the present disclosure without departing from the spirit and scope of the utility model. Accordingly, the scope of the present utility model should be understood and deemed to cover all such other variations or modifications.

Claims (10)

1. A hot water supply system, comprising:

a solar water heater having a first inlet and a first outlet connected to the hot water main to supply hot water to each water unit connected to the hot water main;

A gas water heater having a second inlet and a second outlet, the second outlet being connected to the hot water main so as to supply hot water to each water unit connected to the hot water main;

A first switching valve having a third inlet connected to the first outlet, a third outlet connected to the second inlet, and a fourth outlet connected to the hot water main, and configured to:

communicating the third inlet with the third outlet to heat hot water from the solar water heater using the gas water heater and then to supply the hot water to the hot water main; or (b)

And the third inlet is communicated with the fourth outlet so that hot water flowing out of the solar water heater is directly supplied to the hot water main pipe.

2. The hot water supply system according to claim 1, further comprising:

The second switching valve is arranged on a pipeline from the third outlet to the second inlet and is provided with a fourth inlet, a fifth inlet and a fifth outlet, the fourth inlet is connected with the third outlet, the fifth outlet is connected with the second inlet, the fifth inlet is connected with the cold water main pipe, and the second switching valve is configured to:

Communicating the fourth inlet with the fifth outlet to pass hot water from the solar water heater to the gas water heater; or (b)

And communicating the fifth inlet with the fifth outlet to pass cold water from the cold water header into the gas water heater.

3. The hot water supply system according to claim 2, further comprising:

The first one-way valve is arranged on the pipeline from the cold water main pipe to the fifth inlet, so that water in the gas water heater is prevented from flowing backwards to the cold water main pipe.

4. The hot water supply system according to claim 2, further comprising:

The first temperature sensor is arranged in the solar water heater and is used for detecting the water temperature of the solar water heater;

And the controller is electrically connected with the first temperature sensor, the first switching valve and the second switching valve so as to control and switch the flow paths of the first switching valve and the second switching valve according to the water temperature of the solar water heater.

5. The hot water supply system according to claim 4, further comprising:

the second temperature sensor is arranged in the gas water heater and is used for detecting the water temperature of the gas water heater;

The controller is electrically connected with the second temperature sensor so as to control and switch the flow paths of the first switching valve and the second switching valve according to the water temperature of the gas water heater.

6. The hot water supply system according to claim 4, wherein the solar water heater further comprises:

The solar heat collector is used for converting solar radiation energy into heat energy;

a water storage tank having a heat exchange coil therein;

And the circulating water loop is used for connecting the heat exchange coil and the solar heat collector so as to transfer heat energy to the heat exchange coil through circulating water, and then the heat exchange coil is convenient for heating water in the water storage tank.

7. The hot water supply system according to claim 6, wherein the solar water heater further comprises:

The circulating water pump is arranged in the circulating water loop so as to promote the circulating water to flow; and is also provided with

The controller is also electrically connected with the circulating water pump so as to control the starting and stopping of the circulating water pump according to the water temperature of the water storage tank.

8. The hot water supply system according to claim 1, wherein,

The first inlet is connected with the cold water main pipe; and is also provided with

The hot water supply system further includes:

The second one-way valve is arranged on a pipeline from the cold water main pipe to the first inlet, so that water in the solar water heater is prevented from flowing backwards to the cold water main pipe.

9. The hot water supply system according to claim 1, further comprising:

The first stop valve is arranged on a pipeline from the second outlet to the hot water main pipe.

10. The hot water supply system according to claim 1, further comprising:

The second stop valve is arranged on a pipeline from the fourth outlet to the hot water main pipe.