JPS5838931Y2 - solar water heating device - Google Patents

Description

[Detailed description of the invention] This invention relates to a solar water heating device that prevents freezing and dry heating.

BACKGROUND OF THE INVENTION In today's era of energy conservation, various solar water heaters are widely used for hot water supply, space heating, etc.

One type of solar water heater uses a bottomed vacuum double heat collecting tube consisting of a transparent outer tube and an inner heat collecting tube.
In this solar water heater using vacuum double heat collecting pipes,
Since water, which is a heating medium, is stored inside the heat collecting inner pipe, if the outside temperature drops and the water freezes when the heat collecting inner pipe is full, its volume will decrease. There was a risk that the vacuum double heat collecting tube would be destroyed due to the increase in the amount of heat.

One way to prevent this is to mix an antifreeze agent into the water that is the heating medium, but in this case, the application is limited to heat exchange type solar water heaters, and the range of application is extremely limited. Moreover, it cannot be said to be preferable from the viewpoint of the lifespan of piping materials.

In addition, as another means of preventing the vacuum double heat collection pipe from being destroyed when the outside temperature drops, there is a method of operating a pump that circulates water when the outside temperature is low, but the pump's driving power is wasted, so it is never desirable. It is not a means.

Therefore, in order to prevent the vacuum double heat collection tubes from being destroyed at low temperatures, measures have been taken to drain all the water inside the vacuum double heat collection pipes. If you forget, when the outside temperature rises, the vacuum double heat collection pipe will be in a dry state, and if you supply cold water in this state,
There is a risk that a large temperature difference will occur between the inner and outer surfaces of the inner heat collecting tube and the vacuum double heat collecting tube will be destroyed.

As mentioned above, in conventional solar water heaters using bottomed vacuum double collector pipes, there is no effective means to prevent the vacuum double heat collector pipes from freezing and dry heating. had narrowed the scope of use of solar water heaters.

In view of the above points, this invention provides a solar water heating system that can automatically prevent freezing and dry heating of bottomed vacuum double heat collection pipes, further increasing the utility value of solar water heating systems. It is something to do.

Hereinafter, one embodiment of this invention will be described in detail based on the drawings.

In Fig. 1, reference numeral 1 denotes a bottomed vacuum double heat collecting tube consisting of a transparent outer tube 2 and a heat collecting inner tube 3, with one end closed and the other end open. A plurality of them are installed in parallel to form a hot water generation section.

Each vacuum double heat collecting tube 1 constituting the hot water generation section is
Rooftop or installation frame fixed to the roof (not shown)
It is supported in an appropriately inclined state with one end opening 4 positioned downward and the other end bottom 5 upward, and although this inclination angle is not shown, it can be adjusted to the required inclination angle. It is.

Reference numeral 6 denotes a water supply pipe that supplies water to the heat collection inner pipe 3 inserted into the heat collection inner pipe 3 of each vacuum double heat collection pipe 1, and the water discharge lower at one end of this water supply pipe 6 is connected to the heat collection inner pipe 3. In order to prevent the hot water already generated in the inner heat collecting pipe 3 from mixing with the supplied water, and to discharge the water in the inner heat collecting pipe 3 by the means described later, the lower opening 4 in the inner heat collecting pipe 3 is The other end is connected to and communicates with the water supply header 8.

Reference numeral 9 denotes a hot water conduit inserted into the heat collecting inner tube 3 of each vacuum double heat collecting tube 1 to guide the hot water generated in the heat collecting inner tube 3, and an inlet 10 at one end of this hot water conduit 9 is inserted into the heat collecting inner tube 3 of each vacuum double heat collecting tube 1. In order to guide the hot water generated in the inner pipe 3 and rising to the upper part 5 near the bottom part 5 due to the difference in specific gravity, it opens near the upper bottom part 5 of the heat collecting inner pipe 3, and the other end is connected to the hot water collecting header 11. It is connected and communicating.

Note that 12 is a cap that closes the opening 4 of the vacuum double heat collecting tube 1, and 13 is a cover formed of a heat insulating material surrounding the vicinity of the mouth 4 of the vacuum double heat collecting tube 1.

Reference numeral 14 denotes a hot water tank installed below the lower end of the mouth portion 4 located below each vacuum double heat collecting pipe 1, and this hot water tank 14 is formed of a heat insulating material 15.

16 is a water supply port opened near the bottom of the hot water tank 14, and a supply pipe 17 for supplying water into the hot water tank 14 is connected to this supply port 16. The end is connected to a water pipe or the like, and a supply valve 18 is provided at an appropriate position.

Reference numeral 19 denotes a hot water outlet opening near the bottom of the hot water tank 14, and an outlet pipe 20 for taking out the hot water in the hot water tank 14 is connected to this outlet 19.
0 is equipped with a take-out valve 21 at an appropriate position.

Note that 22 is a communication pipe provided at the upper part of the hot water tank 14, and is for communicating the inside and outside of the hot water tank 14.

Reference numeral 23 denotes an auxiliary tank mounted above the upper end of the bottom portion 5 located above each vacuum double heat collecting tube 1, and this auxiliary tank 23 is formed of a heat insulating material 24.

This auxiliary tank 23 has a water supply port 2 near its top.
5 is opened, and a water outlet 26 is opened at the bottom thereof.

The auxiliary tank 23 has a capacity that can hold at least the amount of water necessary to fill the inside of the heat collecting inner pipe 3 of each vacuum double heat collecting pipe 1 due to the configuration described later. .

Note that 27 is a communication pipe provided at the upper part of the auxiliary tank 23, and is for communicating the inside and outside of the auxiliary tank 23.

Reference numeral 28 denotes a switching valve unit installed below the lower end of the mouth 4 of each vacuum double heat collecting pipe 1, and is a dual switching valve unit that simultaneously switches between the normal operation side circuit a and the abnormal body stop side circuit. It is equipped with valves 29a and 29b.

Reference numeral 30 designates a first water supply pipe that connects and communicates the hot water tank 14 and the auxiliary tank 23 , one end of which has an inlet 31 that opens near the bottom of the hot water tank 14 , and the other end that connects to the water supply port of the auxiliary tank 23 . Auxiliary water supply pipe 32 connected to 25
is connected to.

33 is a second water supply pipe connecting the auxiliary tank 23 and the switching valve unit 28, one end of which connects the auxiliary tank 23 and the switching valve unit 28;
The other end is connected to one of the switching valves 29 a of the switching valve unit 28 .

35 is a water supply and drainage pipe connecting the switching valve unit 28 and the water supply pipe 6 inserted into the heat collecting inner pipe 3 of each vacuum double heat collecting pipe 1; one end thereof is connected to the switching valve 29a of the switching valve unit 28; It is connected to a branch point 36 at an intermediate position with the valve 29b, and the other end is connected to the water supply header 8.
It is connected to the water supply pipe 6 via.

The second water supply pipe 33 and the water supply and drainage pipe 35 are communicated with each other via a switching valve 29 a located in the normally operating circuit a of the switching valve unit 28 .

Therefore, the auxiliary tank 23 and the upper bottom part 5 of each vacuum double heat collecting pipe 1 are connected and communicated through the second water supply pipe 33, water supply and drainage pipe 35, water supply header 8, and water supply pipe 6 with the switching valve unit 28 interposed therebetween. It turns out.

Further, when each switching valve 29a, 29b switches to the abnormal body stop side circuit, the communication between the second water supply pipe 33 and the water supply and drainage pipe 35 is cut off, and the switching valve unit 28 side of the second water supply pipe 33 is cut off. The end is connected to one switching valve 29a
The end of the water supply and drainage pipe 35 on the switching valve unit 28 side communicates with the drain pipe 37 via the other switching valve 29b which has been switched to the abnormal body stop circuit.

38 is a drain pipe 3 opened at the upper part of the hot water tank 14
7 outlet.

Note that the drain pipe 37 is provided with two outlet ports 38, one inside and one outside the hot water tank 14, and an appropriate switching valve (not shown) is provided so that the water in the Hayatetsu inner pipe 3 can be discharged from the hot water tank 14. It is also possible to configure it so that it can be switched between inside and outside.

39 is a hot water supply pipe that connects and communicates the hot water conduit 9 inserted into the heat collection inner pipe 3 of the vacuum double heat collection pipe 1 with the hot water tank 14; one end thereof is connected to the hot water pipe 9 through the hot water collection header 11; Connected to the hot water outlet 40 at the other end.
is open at the top of the hot water tank 14.

In addition, 41 is a communication pipe provided in the hot water collection header 11, and is for communicating the inside and outside of each vacuum double heat collection pipe 1.

42 is a pump installed in the first water supply pipe 30, which is used to forcefully circulate water, which is a heating medium in the hot water tank 14, to the auxiliary tank 23, the vacuum double heat collection pipe 1, and the hot water tank 14. It is provided at an appropriate position close to the tank 14.

Reference numeral 43 denotes a first check valve provided in the first water supply pipe 30, which prevents the backflow of water sent out by the pump 42, and is provided at an appropriate position close to the pump 42.

Here, in the process of sending water from the first water supply pipe 30 to the second water supply pipe 33, the amount of water necessary to fill all of the heat collection inner pipes 3 is stored and maintained in the auxiliary tank 23 as reserve water. The structure of the mechanism will be explained.

44 is a ball tap that detects the full level of water supplied into the auxiliary tank 23 from the hot water tank 14 via the first water supply pipe 30 and the auxiliary water supply pipe 32 by the pump 42; When it detects that the water has reached the full water level, the water supply port 25 is closed to stop the water supply, and when it detects that the water in the auxiliary tank 23 has fallen below the full water level, the water supply port 25 is opened to supply water to the auxiliary tank. 23.

Here, the full water level in the auxiliary tank 23 is defined as the amount of water required to fill up all of the heat collecting inner pipes 3 when all of the heat collecting inner pipes 3 are empty. It is a part at the water surface level that is retained and maintained as water.

45 is a bypass pipe that connects and communicates the first water supply pipe 30 and the second water supply pipe 33.

46 is a throttle valve such as an orifice provided in the auxiliary water supply pipe 32, and is used to adjust the amount of water supplied from the first water supply pipe 30 into the auxiliary tank 23.

That is, the flow rate of water from the first water supply pipe 30 is adjusted as appropriate to the flow rate of water supplied into the auxiliary tank 23 and the flow rate of water flowing through the bypass pipe 45.

The amount of water supplied into the auxiliary tank 23 by the throttle valve 46 is adjusted by adjusting the opening degree of the throttle valve 46, and the opening degree is adjusted so that the auxiliary tank 23 is filled with water at a full level. The opening is set so that a larger amount of water enters the auxiliary tank 23 from the water supply port 25 than the amount of water flowing out from the outlet 26 of the auxiliary tank 23,
Water at a full level is always kept in the auxiliary tank 23 as reserve water.

Further, the opening degree of the throttle valve 46 is set in advance depending on the scale of the solar water heating device.

A second check valve 47 prevents the water that has entered the bypass pipe 45 from flowing back into the auxiliary tank 23 from the outflow pipe 34.

As mentioned above, the ball tap 44, the bypass piping 45,
The throttle valve 46 and the second check valve 47 constitute a mechanism for retaining and maintaining reserve water in the auxiliary tank 23, but this mechanism may be constructed as shown in FIG. 2.

According to this, the water supply port 25 at the other end of the auxiliary water supply pipe 32, which has one end connected to the first water supply pipe 30, is opened at the bottom of the auxiliary tank 23, and the outflow pipe 34, which has one end connected to the second water supply pipe 33, is opened at the bottom of the auxiliary tank 23. At least the amount of water necessary to fill all the heat collecting inner pipes 3 when all of the heat collecting inner pipes 3 are empty is poured into the auxiliary tank 23 through the outlet 26 at the other end. A throttle valve 46 is provided in a bypass pipe 45 that opens at a portion at the water surface level to be held and maintained as reserve water and further connects and communicates the first water supply pipe 30 and the second water supply pipe 33.

48 is a temperature sensor that detects the outside temperature and induces switching of each of the switching valves 29 a and 29 b of the switching valve unit 28 to either the normal operation side circuit a or the abnormal body stop side circuit; For example, if the temperature just before water freezes is set at 2 to 4 degrees Celsius, and the temperature sensor 48 detects this when the outside temperature falls below the set temperature, each of the switching valves 29 a and 29 b of the switching valve unit 28 will malfunction. When the temperature sensor 48 detects that the outside temperature has exceeded the set temperature, the switching valves 29a and 29b each switch to the normal operation side circuit a. be.

By detecting the outside temperature by this temperature sensor 48, each switching valve 29a, 29b of the switching valve unit 28 is activated.
To explain one example of a specific implementation that induces switching, a diaphragm or bellows is used, gas or liquid is sealed inside, and the change in volume of the gas due to temperature change is used to convert that change into a change in stroke. The temperature sensor 48 may be configured to convey information to induce switching of each of the switching valves 29 a and 29 b, and is not particularly limited to any other device as long as it can induce switching of each of the switching valves 29 a and 29 b. can be used.

In this embodiment, the temperature sensor 48 is used to detect the outside temperature. The temperature inside the tube may be detected.

Here, the mounting position of the switching valve unit 28 is as follows.
When the switching valves 29 a and 29 b of the switching valve unit 28 are switched to the abnormal body stop circuit that cuts off communication between the second water supply pipe 33 and the water supply and drainage pipe 35 due to the detection of the outside temperature by the temperature sensor 48, The water in the heat collection inner pipe 3 is naturally drained by its own weight and is transferred to the hot water tank 14 via the water supply pipe 6, water supply header 8, water supply and drainage pipe 35, and drain pipe 37.
In order to discharge water into the interior, the drain pipe 37 is positioned below the lower end of the opening 4 located below the heat collecting inner pipe 3 and maintains an appropriate water head difference ΔH1 from the lower end of the opening 4.
The upper end of the hot water tank 14 maintains an appropriate water head difference ΔH2 from the upper part of the hot water tank 14, which is the discharge port 38 of the hot water tank 14.

Note that the mounting position of the switching valve unit 28 is not limited to the above embodiment, and may be at least below the lower end of the mouth portion 4 of the vacuum double heat collecting tube 1.

In this case, the switching valve unit 28 and the drain pipe 37
An appropriate water head difference ΔH2 may be maintained between the outlet port 38 and the outlet port 38, and the opening may be opened at an appropriate position.

Here, to explain the capacity of water in the hot water tank 14, the full water level in the hot water tank 14 is
This is the part where the minimum necessary space is left in the upper part of the water tank 4, and the water level is configured so that the water level can be detected from the outside by an appropriate means.

The reason why the full water level in the hot water tank 14 is set to the part where the minimum necessary space is left in the upper part of the hot water tank 14 is that when the water in each heat collecting inner pipe 3 is discharged based on the detection of the outside temperature by the temperature sensor 48. This is to allow air to flow through each heat collecting inner pipe 3 through the hot water supply pipe 39 opened at the upper part of the hot water tank 14. In particular, as shown in the embodiment, the discharge port 38 of the drain pipe 37 is connected to the hot water tank 14. In the case of opening inward, the space left above the full water level in the hot water tank 14 needs to be a space capable of accommodating at least all the water in each heat collecting inner pipe 3 in a full state.

Next, the operation of this invention will be explained.

First, the circulation of water, which is a heating medium, in the solar water heating device according to this invention will be explained.

As a prerequisite for water circulation, it is natural that the outside temperature is higher than the freezing temperature of water, and the temperature sensor 4
8 to each switching valve 29 of the switching valve unit 28.
a and 29 b are respectively located in the normally operating side circuit a,
The second water supply pipe 33 and the water supply and drainage pipe 35 are in communication with each other.

Further, the opening degree of the throttle 46, which constitutes a mechanism for holding and maintaining reserve water in the auxiliary tank 23, is set in accordance with the scale of the solar water heating system.

Therefore, first, the supply valve 18 is opened to supply water from the supply pipe 17 into the hot water tank 14 .

Next, when the pump 42 is operated, the water supplied into the hot water tank 14 is pressurized by the pump 42, ascends through the first check valve 43 and the first water supply pipe 30, and bypasses the auxiliary water supply pipe 32. Branches into piping 45.

The water that has flowed into the bypass pipe 45 flows into the second water supply pipe 33 without flowing into the auxiliary tank 23 due to the second check valve 47 provided in the outflow pipe 34 .

On the other hand, the water that has flowed into the auxiliary water supply pipe 32 is
The water flows into the auxiliary tank 23 through the water supply port 25.

Here, the opening degree of the throttle valve 46 provided in the auxiliary water supply pipe 32 is such that a larger amount of water flows into the auxiliary tank 23 from the water supply port 25 than the amount of water flowing out from the outlet 26 opened at the bottom of the auxiliary tank 23. Since the opening is set such that water flows into the auxiliary tank 23, water gradually accumulates in the auxiliary tank 23.

When the water that has flowed into the auxiliary tank 23 accumulates and reaches the full water level, the ball tap 44 detects this and opens the water supply port 2.
5 to stop supplying water to the auxiliary tank 23.

Therefore, at this time, all the water that has risen through the first water supply pipe 30 will flow into the bypass pipe 45.

Further, since water is flowing out from the outlet 26 opened at the bottom of the auxiliary tank 23, the water level of the water stored in the auxiliary tank 23 gradually decreases.

When the ball tap 44 detects that the water stored in the auxiliary tank 23 has fallen below the full level, the water supply port 25 is opened to supply water into the auxiliary tank 23 again.

That is, by repeatedly opening and closing the water supply port 25 based on the detection of the ball tap 44, reserve water is always held and maintained in the auxiliary tank 23.

Now, the water flowing out from the outlet 26 of the auxiliary tank 23 is
The water from the bypass pipe 45 joins with the second water supply pipe 33
The water that has flowed into the second water supply pipe 33 flows into the water supply header 8 through the normally operating side circuit a of the switching valve 29a in the switching valve unit 28 and the water supply and drainage pipe 35, and then flows into the water supply header 8 through each vacuum double heat collection pipe 1. The water flows from the water supply pipe 6 inserted into the heat collecting inner pipe 3 into the lower opening 4 of each heat collecting inner pipe 3.

When each heat collection inner pipe 3 is filled with water, the water then flows into the hot water collection header 11 through a hot water conduit 9 having an inlet 10 opened near the bottom 5 above each heat collection inner pipe 3. The hot water then flows into the hot water tank 14 through the hot water supply pipe 39 and from the hot water outlet 40 opened at the top of the hot water tank 14 .

The water supplied from the supply pipe 17 into the hot water tank 14 is gradually stored in the hot water tank 14 while repeating the above-mentioned circulation.

Then, the water stored in the hot water tank 14 is transferred to the hot water tank 1.
4, the supply valve 18 of the supply pipe 17 is closed to stop the supply of water to the hot water tank 14.

Therefore, water is supplied to the pump 4 while the hot water tank 14, auxiliary tank 23, and each heat collection inner pipe 3 are filled.
Circulate by 2.

Next, to explain hot water generation during solar radiation, the water is circulated by the pump 42 as described above, and is heated by the solar radiation in each heat collecting inner pipe 3 during this circulation.

Then, by repeating the circulation during solar radiation, the hot water tank 14
The temperature of the water inside gradually rises and becomes hot water.

When the hot water generated in this manner is to be taken out from the hot water tank 14, the operation of the pump 42 is first stopped, and then the take-out valve 21 provided in the take-out pipe 20 is opened to take out the hot water from the hot water tank 14.

Hot water is generated and taken out as described above, and the case where the outside temperature drops, particularly at night in winter, will be described next.

Normally, the pump 42 is stopped at night, so water is not circulating.Also, even if hot water is taken out from the hot water tank 14, reserve water remains in the auxiliary tank 23, and each The inside of the heat collecting inner tube 3 is also in a full state.

If the outside temperature drops in this state and the water in the inner heat collection tube 3 freezes, the vacuum double heat collection tube 1 will be destroyed due to the volume expansion due to freezing of the water.

In this invention, when the outside temperature approaches the temperature at which water freezes, the temperature sensor 48 detects this and the switching valve unit 2
The switching valves 29a and 29b of 8 are automatically and simultaneously switched from the normal operation side circuit a to the abnormal body stop side circuit.

By switching each of the switching valves 29 a and 29 b to the abnormal body stop side circuit, the second water supply pipe 33 and the water supply and drainage pipe 35 are cut off, and the end of the second water supply pipe 33 on the switching valve unit 28 side is closed. One switching valve 29a is closed, and the end of the water supply and drainage pipe 35 on the switching valve unit 28 side is connected to the drain pipe 37 via the other switching valve 29b, which is switched to the abnormal body stop circuit. .

At this time, the tip portion of the switching valve unit 28 side of the water supply and drainage pipe 35 and the lower opening portion 4 of each vacuum double heat collecting pipe 1
Due to the existence of the water head difference ΔH1 between the
A water supply header 8 from a water supply pipe 6 having a water discharge lower in the vicinity;
The water is discharged into the hot water tank 14 from the outlet 38 of the drain pipe 37 via the water supply and drainage pipe 35 and the other switching valve 29 b located on the abnormal body stop side circuit of the switching valve unit 28 . When reaching the outlet 38, the water head difference ΔH3 between the lower opening 4 of each vacuum double heat collecting pipe 1 and the discharge port 38 increases, promoting drainage, and the lower water discharge of the water supply pipe 6 Since the heat collecting inner pipes 3 are located near the lower openings 4, almost all of the water in each heat collecting inner pipe 3 is discharged, and even if the outside temperature reaches the freezing temperature of water, each vacuum pipe is There is no possibility that the heavy heat collecting pipe 1 will be destroyed.

Note that even when hot water is not taken out from the hot water tank 14 and the pump 42 is not operating, the temperature sensor 48 detects the outside temperature below the set temperature and operates in the same way, so that each vacuum double heat collecting pipe 1 will not destroy it.

In this case, even if the water in each heat collection inner pipe 3 is discharged into the hot water tank 14 while the hot water tank 14 is full of water, the full water level in the hot water tank 14 is
4, the water discharged from each heat collecting inner pipe 3 flows into the hot water tank 1.
Not only does it not overflow from the heat collecting inner pipes 4, but also all the water in each heat collecting inner pipe 3 can be reliably discharged.

Next, a case will be described in which the outside temperature rises after all the water in each heat collection inner pipe 3 is discharged.

If left in this state, each vacuum double heat collecting tube 1 will be in a dry state due to solar radiation, causing destruction or performance deterioration due to overheating.

In this device, when the outside temperature rises, which has dropped to the freezing temperature of water, the temperature sensor 48 detects this, and each switching valve 29a, 29b of the switching valve unit 28 switches to the normal operation side because the switching valve 29a, 29b switches to the abnormal body stop side circuit. They each switch automatically and simultaneously to circuit a.

By switching 9 of each of the switching valves 29 a and 29 b to the normally operating circuit a, the second water supply pipe 33 and the water supply and drainage pipe 35 are brought into communication, and as a result, the reserve water in the auxiliary tank 23 is transferred to the auxiliary tank 23 . Due to the siphon effect due to the water head difference with each vacuum double heat collecting pipe 1, each It flows into the heat collecting inner tube 3 of the vacuum double heat collecting tube 1 and becomes full.

Therefore, each vacuum double heat collecting pipe 1 will not be in a dry state, and damage and performance deterioration due to overheating of each vacuum double heat collecting pipe 1 can be prevented, and even if water is newly supplied, water will not be heated in each case. It mixes with the hot water in the inner heat collecting tube 3 to prevent damage to each vacuum double heat collecting tube 1 due to rapid cooling, so-called heat shock.

If water is not supplied, the temperature of the hot water in each heat collection inner pipe 3 will rise to nearly 10°C, and even if steam is generated, the steam will flow through the hot water conduit 9, the hot water collection header 11. Since the hot water is discharged into the hot water tank 14 via the hot water supply pipe 39, the vacuum double heat collecting pipes 1 will not be destroyed due to overpressure within the heat collecting inner pipes 3.

Next, the operation of another embodiment shown in FIG. 2 will be explained.
The same functions as those of the embodiment shown in FIG. 1 will be omitted, and only the different functions will be explained.

First, the normal circulation of water for hot water production will be explained.

First, the opening degree of the throttle valve 46, which constitutes a mechanism for retaining and maintaining reserve water in the auxiliary tank 23, is such that the flow path loss due to the throttle valve 46 is slightly larger than the water head difference Δh between the outlet 26 and the throttle valve 46. It is an opening degree that would be fine if it were not necessary, and it is an opening degree that is close to fully open.

The water pressurized by the pump 42 and rising through the first water supply pipe 30 branches into an auxiliary water supply pipe 32 and a bypass pipe 45 .

The water that has flowed into the bypass pipe 45 does not flow into the auxiliary tank 23 but flows into the second water supply pipe 33 due to the existence of the water head difference Δh between the outlet 26 and the throttle valve 46 .

On the other hand, water flowing into the auxiliary water supply pipe 32 is transferred to the auxiliary tank 2.
The water flows into the auxiliary tank 23 from the water supply port 25 opened at the bottom of the tank 3, and is gradually stored in the auxiliary tank 23.

The water flowing into the auxiliary tank 23 is stored and the water flows into the auxiliary tank 2.
When the water level at the outlet 26 of No. 3 is reached, the auxiliary tank 2
The water overflows from the outlet 26 while holding and maintaining reserve water in the water outlet 26.

The water overflowing from the outlet 26 flows into the outflow pipe 34 , joins with the water from the bypass pipe 45 , and flows into the second water supply pipe 33 .

That is, the outlet 26 of the auxiliary tank 23 and the throttle valve 4
6, reserve water is always held and maintained in the auxiliary tank 23.

Next, a case will be described in which the outside temperature rises after all the water in each heat collection inner pipe 3 is discharged.

Each switching valve 29a, 29 is controlled by the temperature sensor 48.
When the circuits b are switched to the normal operation side circuit a and the second water supply pipe 33 and the water supply and drainage pipe 35 are communicated, the reserve water in the auxiliary tank 23 becomes equal to the water head difference between the auxiliary tank 23 and each vacuum double heat collecting pipe 1. Due to the siphon effect, the auxiliary water supply pipe 32, bypass pipe 45, second water supply pipe 33, switching valve 29a of the switching valve unit 28, water supply and drainage pipe 35
, water supply header 8, water supply pipe 6, and each vacuum double heat collection pipe 1
The heat flows into the heat collection inner tube 3 and becomes full.

As mentioned above, since this device has the above-mentioned structure and functions, it can not only be used to generate and take out hot water, which is the original purpose of a solar water heating device.
When the outside temperature or the water in the vacuum double heat collection pipe approaches freezing temperature, the temperature sensor detects this and automatically switches each switching valve of the switching valve unit from the normally operating side circuit to the abnormal body stop side circuit. Moreover, since all the water in the vacuum double heat collecting tube is discharged outside the tube by switching at the same time, it is possible to reliably prevent the vacuum double heat collecting tube from being destroyed due to freezing of water within the vacuum double heat collecting tube.

After draining the water in the vacuum double heat collecting pipe, when the outside temperature or the temperature inside the vacuum double heat collecting pipe rises, the temperature sensor detects this again and indicates that each switching valve in the switching valve unit is abnormal. By automatically and simultaneously switching from the stop side circuit to the normal operation side circuit, the reserve water remaining in the auxiliary tank flows into the vacuum double heat collection pipe and becomes full, so even if the temperature rises, The vacuum double heat collection tube will not be in an empty state, and damage and performance deterioration due to overheating of the vacuum double heat collection pipe can be reliably prevented, and even if new water is supplied, water will not remain in the vacuum double heat collection pipe The temperature of the hot water inside the vacuum double heat collection tube rises to 100℃ without supplying water.
Even if steam is generated nearby, this steam will be released into the hot water tank, which will prevent damage due to overpressure in the vacuum double heat collection tube.

In addition, the vacuum double heat collecting pipe is supported in an appropriately inclined state with its mouth facing downward and its bottom facing upward, and the piping is configured so that the water in the heat collecting inner pipe is naturally drained by its own weight. Therefore, the piping configuration becomes simple, and the water inside the heat collecting pipe can be discharged easily and reliably, further increasing its utility value as a solar water heating system.

Furthermore, since the structure is simple, it is easy to manufacture and can be obtained at low cost.

Note that this invention is not limited to the above-mentioned embodiments, and can be implemented in modes other than the above-mentioned embodiments.

[Brief explanation of the drawing]

The drawings show an embodiment of this invention; FIG. 1 is a partially schematic cross-sectional view, and FIG. 2 is a cross-sectional view showing another embodiment of the auxiliary tank. 1... Vacuum double heat collecting tube, 4... Mouth part,
5...Bottom, 6...Water pipe, 9...
...Hot water conduit, 14...Hot water tank, 16.
... Supply port, 19 ... Output port, 23 ...
...Auxiliary tank, 28...Switching valve unit l-129a, 29 b...Switching valve,
30... First water supply pipe, 33... Second water supply pipe, 35... Water supply and drainage pipe, 37...
...Drain pipe, 39...Hot water supply pipe, 42
...Pump, 44...Ball tap,
45... Bypass piping, 46... Throttle valve, 48... Temperature sensor, a... Normally operating circuit, b... Abnormal Body stop side circuit.

Claims (1)

[Scope of utility model registration request] One or more bottomed vacuum double heat collecting pipes installed on a rooftop or the like with a required inclination angle, a water supply port and a hot water outlet, and installed below the lower end of the vacuum double heat collecting pipes. a hot water tank, an auxiliary tank that has a capacity to hold enough water to fill at least all of the vacuum double heat collection pipes and is located above the upper end of the vacuum double heat collection pipe; and the vacuum tank. 4 of the switching valve unit installed below the lower end of the double heat collecting pipe
The vacuum double heat collecting pipe is inclined with one end located downward and the other end bottom located upward, and the switching valve unit is a double switching valve unit that switches between a normal operation side circuit and an abnormal body stop side circuit. The hot water tank and the auxiliary tank are connected and communicated through a first water supply pipe, and the auxiliary tank and the lower openings of all the vacuum double heat collecting pipes are connected to each other through the switching valve unit. The second water supply pipe and the water supply and drainage pipe are connected and communicated, and the second water supply pipe and the water supply and drainage pipe are shut off by the circuit on the abnormal body stop side of the switching valve unit, so that the second water supply pipe is closed on one side, and the second water supply pipe is closed on the other hand. The water supply and drainage piping and the drain pipe are connected and communicated via a side circuit, the upper bottom of the vacuum double heat collecting pipe and the hot water tank are connected and communicated through the hot water supply piping, and the auxiliary tank is further bypassed for heating. A pump that forcibly circulates water as a medium and detects the outside temperature or the temperature inside the vacuum double heat collecting pipe and switches the dual switching valve of the switching valve unit to either the normal operation side circuit or the abnormal body stop side circuit. A solar water heating device characterized by having a temperature sensor installed in the circuit for switching operation.