JPH0440129Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a natural circulation type solar water heater equipped with a hot water storage tank placed on a roof or the like.

[Background of the idea]

FIG. 6 is a schematic diagram of a conventional solar water heater.
In FIG. 6, the solar water heater has a heat collector section 10.
and a hot water storage tank section 12. The heat collector section 10 is formed by press-forming two thin plates and then seam-welding them to integrally form a plurality of heat collecting pipes 16, an upper header 18, a lower header 20, and an inlet passage 22. The plurality of heat collecting pipes 16 are formed parallel to each other and communicate with the upper header 18 and the lower header 20, respectively. The lower header 20 has one end connected to the lower end of an inflow path 22 parallel to the heat collecting pipe 16, and a drain port 24 provided at the other end. An outlet 26 is formed in the upper header 18 at the end opposite to the connection side of the inlet passage 22 of the lower header 20. It is connected to the tank 30. Further, an inflow port 32 is formed at the upper end of the inflow path 22, and this inflow port 32 is connected to the hot water storage tank 30 via a connecting pipe 34. The hot water storage tank 30 is surrounded by a heat insulating material 36 and is connected to a water supply pipe 38 and a hot water supply pipe (not shown). Furthermore, a ball tap 40 is provided in the hot water storage tank 30, and a water supply pipe 38 is provided with a ball tap 40.
It is now possible to control the water supply from

In the solar water heater as described above, when the hot water in the hot water tank 30 is taken out by the hot water supply pipe (not shown), the water level in the hot water tank 30 decreases, and the ball tap 40 descends, causing water to flow from the water supply pipe 38. will be replenished. The water in the hot water tank 30 is transferred to the connecting pipe 34.
It enters the heat collector section 10 from the inlet 32 through the inlet.
The water then flows down the inflow channel 22 to the lower header 20.
The hot water enters the interior, is heated by the sun, rises in the heat collecting pipe 16, reaches the upper header 18, and enters the hot water storage tank 30 again from the outlet 26 via the connecting pipe 28. Note that the drain port 24 serves as a discharge port for cleaning water when the water heater needs to be cleaned due to the occurrence of scale or dirt in the water heater.

In solar water heaters, it is necessary to expose the heat collection pipe 16 to sunlight, and it is difficult to prevent freezing as the ambient temperature drops, so the heat collector may freeze in cold regions. Generally, freezing starts from the area with the least amount of water. Upper header 1
8. The lower header 20 and the inflow channel 22 are formed larger than the inlet 32 and the outlet 26, have a large amount of water, and are relatively long. For this reason, freezing does not proceed in an orderly manner from the upper and lower headers 18 and 20 and the inlet passage 22 toward the inlet 32 and the outlet 26, and the insides of the upper and lower headers 18 and 20 and the inlet passage 22 are completely frozen. In some cases, the vicinity of the inlet 32 and outlet 26 freezes before the operation is completed, resulting in the inlet 32 and outlet 26 being blocked. Therefore, there are some examples of keeping the area around the inlet 32 and outlet 26 warm, but there is no perfect solution.
A phenomenon occurred in which the vicinity of the inlet 32 and outlet 26 were frozen before the lower headers 18 and 20 and the inlet passage 22 were frozen.

The inlet 32 and the outlet 26 are on the top, the bottom header 18,
20. If the inlet channel 22 freezes before it is completely frozen, the volume expansion due to the freezing of the water remaining in the upper and lower headers 18, 20 and the inlet channel 22 will concentrate in one place, causing the heat collecting plate 14 to partially It bulges out and deforms. When this kind of transformation is repeated several to dozens of times,
The heat collecting plate 14 was significantly deformed and even broke.

[Purpose of invention]

An object of the present invention is to provide a solar water heater that can prevent damage to a heat collecting plate due to freezing of water in the heat collector.

[Summary of the idea]

The present invention includes a heat collector having a plurality of parallel heat collection pipes that communicate with an upper header and a lower header, and an inflow channel that leads water supply to the lower header, and a heat collector provided above the heat collector. In a solar water heater equipped with a hot water storage tank connected to an inlet of an inflow channel and an outlet of an upper header via respective connecting pipes, the inflow channel,
The cross sections of the upper header and the lower header are each formed into a shape that has a larger heat capacity than the respective heat collection pipes, and each connecting pipe is insulated, and at least the inflow channel of the lower header and the upper header is At least one type of heater for anti-freezing is installed on the back side of the channel to ensure that the inlet channel freezes last, and when the volume expansion occurs due to freezing of water in the collector, the water in the collector can be The hot water is allowed to escape into the storage tank via the inflow path, and is configured to prevent the heat collecting plate from being destroyed.

[Example of idea]

A preferred embodiment of the solar water heater according to the present invention will be described in detail with reference to the accompanying drawings. Note that the same reference numerals are given to the parts corresponding to the parts explained in the prior art, and the explanation thereof will be omitted.

FIG. 1 is a schematic diagram of an embodiment of a solar water heater according to the present invention.

In FIG. 1, the heat collector section 10 includes a hot water storage tank 30.
The part that guides the water from the heat collection pipe 16 to the heat collection pipe 16 and the part that leads the water warmed in the heat collection pipe 16 to the hot water storage tank 30, that is, at least the inflow pipe 22 of the lower header 20 and the upper header 18. Freeze prevention heaters (heaters) 42 and 4 are installed on the back side of the
4 are arranged. That is, the heater 42 disposed on the inflow side of the heat collection pipe 16 is designed to heat the connection pipe 34, the inflow port 32, the inflow path 22, and the lower header 20. Further, a heater 44 disposed on the outflow side of the heat collection pipe 16 is adapted to warm the upper header 18, the outflow port 26, and the connecting pipe 28. These heaters 42 and 44 are connected to the inflow passage 22, the lower header 20, and the upper header 18 as shown in FIG.
It is disposed at the center of the back surface over the entire length of the heat collecting plate 14 so as not to block sunlight entering the heat collecting plate 14. These heaters 42, 44 are
For example, it is possible to use a belt-shaped heater in which a heating element is embedded in resin, and this belt-shaped heater is attached to the heat collecting plate 1.
By pasting it on the back side of 4, it can be placed in a predetermined position. Note that the water channels such as the inlet channel 22 may not only have a hexagonal cross section as shown in FIG. 2, but also have a constricted upper and lower center as shown in FIG. Even if the lower center part is constricted, a band-shaped heater can be attached and arranged in the same way.

In the embodiment configured as described above, the heaters 42 and 44 are connected to the upper and lower headers 18 and 20, and the inlet passage 2.
A temperature sensor (not shown) detects the water temperature in the heat collector 2 or the air temperature in the heat collector part 10, and turns on and off. The heaters 42 and 44 generally
The water temperature in the lower headers 18, 20 and inlet channel 22 is 0.5
The temperature is controlled so that it does not fall below ~1.0℃. However, if the outside air temperature becomes even lower, the water temperature in these areas may drop below 0°C. In such a case, water channels such as the upper header 18, lower header 20, and inlet channel 22 also begin to freeze. This freezing starts from a state where only water 46 exists in the heat collecting pipe 16 and the water channel as shown in FIG. As shown, the front sides of the upper header 18, lower header 20, and inflow channel 22 begin to freeze, and the ice layer 48 gradually becomes thicker. As the temperature further decreases, the upper and lower headers 18, 20,
Freezing of the inlet channel 22 progresses as shown in FIG. 4 C and D,
When the temperature is extremely low, these upper headers 18,
The insides of the lower header 20 and the inflow path 22 are also completely frozen.

However, even if the water in the upper header 18, lower header 20, and inflow channel 22 completely freezes, before these completely freeze, the heaters 42 and 44 must be heated to a minimum level as shown in FIG. 4D. All the water pushed out due to volume expansion due to freezing is returned to the hot water storage tank 30, and the heat collecting plate 14
Since no significant pressure is applied to the heat collecting plate 14, significant expansion of the heat collecting plate 14 can be prevented. For this reason,
Even if the water in the heat collector section 10 completely freezes, the heat collector plate 14 will not be destroyed.

In addition, in the above embodiment, the connecting pipes 28, 3
Although the case where the heaters 44, 42 are also provided in the portion 4 has been described, if the connecting tubes 22, 34 are sufficiently kept warm, there is no need to provide a heater in the connecting tubes 28, 34. In addition, the upper header 18,
Lower header 20, inflow path 22 and connecting pipes 28, 3
By making the heat generation amount of the heater different in each part of 4, that is, using at least one kind, water in the heat collector part 10 can be reliably released into the hot water storage tank 30.

FIG. 5 is a schematic diagram of a heat collector section of another embodiment of the solar water heater according to the present invention. In this embodiment, the heater 4 disposed on the inflow side of the heat collection pipe 16
A heater 4 is disposed along the entire length of the inflow passage 22, extending from the center of the lower header 20 to the connection part of the inflow passage 22, and a heater 4 is disposed on the outflow side of the heat collection pipe 16.
4 is disposed from the center of the upper header 18 to the outlet 28. By configuring in this way, it is possible to obtain the same effects as in the embodiment described above, and at the same time, it is possible to reduce the energy required for freezing prevention. In addition, the heat collector part 10
is so-called vertically long (the axial length of the heat collection pipe 16 of the heat collector section 10 is larger than the axial length of the header), by providing a heater only in the inlet channel 22, the same as above can be achieved. effect can be obtained.

[Effect of idea]

As explained above, according to the present invention, even if the water in the heat collector freezes, the heater ensures that at least the minimum unfrozen part of the inlet channel is immediately before freezing, and all the water is transferred to the hot water tank. It is possible to prevent damage to the heat collecting plate.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an embodiment of the solar water heater according to the present invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Fig. 3 A and B are schematic diagrams showing the shapes of waterways such as inflow channels. 4A to 4D are explanatory diagrams showing the frozen state of water in the heat collector, FIG. 5 is a schematic diagram of the heat collector section of another embodiment of the solar water heater according to the present invention, and FIG. The figure is a schematic diagram of a conventional solar water heater. 10... Heat collector section, 12... Hot water storage tank section, 14...
... Heat collection plate, 16 ... Heat collection pipe, 18 ... Upper header, 20 ... Lower header, 22 ... Inflow path, 30 ...
...Hot water tank, 42, 44...Heater.

Claims (1)

[Claims for Utility Model Registration] 1. A heat collector having a plurality of parallel heat collection pipes that communicate with an upper header and a lower header, and an inflow channel for guiding water supply to the lower header, and this heat collector. In the solar water heater, the solar water heater includes a hot water storage tank provided above the container and connected to the inlet of the inflow channel and the outlet of the upper header through respective connecting pipes, the inlet channel, the upper header The cross section of each of the lower headers is formed into a shape having a larger heat capacity than the respective heat collecting pipes, and each connecting pipe is insulated, and the cross section of the lower header and the lower header is A solar water heater, characterized in that at least one type of heater for preventing freezing is provided on the back surface of at least the inlet channel. 2. A utility model registration request characterized in that each heater is provided from approximately the center of the upper header to the outflow port, and from approximately the center of the lower header to the inlet of the inflow channel. A solar water heater according to scope 1.