JP2953110B2 - Vacuum solar heat collector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum solar heat collecting apparatus in which a cylindrical water storage container is disposed inside a glass container.

[0002]

2. Description of the Related Art Various types of solar heat collectors utilizing the heat energy of sunlight as a heat source have been proposed in various forms, and are widely used in the field of water heaters. Various types of vacuum solar heat collectors have also been invented, and the present applicant has proposed a vacuum solar heat collector in which a cylindrical water storage container is arranged inside a glass container in Japanese Patent Application No. 62-16424. .

This application discloses a transparent long cylindrical glass container having one end sealed and the other end squeezed to a small diameter, an opening sealed at one end and the other end squeezed to a small diameter. And
A cylindrical metal water storage container coaxially disposed inside the glass container via a support and having an outer surface coated with a selective absorption film; and a glass container and the inside of the water storage container penetrating through the open ends of the water storage container. A first tube inserted to the vicinity of the sealed end of the container, a second tube penetrating the open end of the glass container and connected to the open end of the water storage container, and a sealing fitting for sealing the opening of the glass container. And a vacuum solar heat collecting apparatus in which a vacuum is provided between the glass container and the water storage container.

[0004] In the case of using this vacuum solar heat collecting apparatus, the open ends of the glass container and the water storage container are arranged lower than the sealed end, water is supplied into the water storage container from the second pipe, and hot water is taken out. A method in which the opening is performed from the first pipe or the second pipe, the opening ends of the glass container and the water storage container are arranged higher than the sealed end, water is supplied to the inside of the water storage container from the first pipe, and hot water is taken out. There is a method performed from the second tube.

[0005]

However, when the above-mentioned vacuum solar heat collecting apparatus is used in the former method, an air reservoir is formed above the inside of the water storage container, and the air reservoir is generated from the water storage. Since chlorine gas and the like are contained, there is a problem that the metal water storage container is easily corroded. Further, in this method, it is impossible to take out hot water without supplying new water into the water storage container, that is, so-called lot hot water extraction is impossible. When taking out hot water, always supply new water into the water storage container. Since it is necessary, there is a problem that hot water is mixed with water and the water temperature is lowered.

On the other hand, in the case of using the latter method as well, it is impossible to take a lot of water, and since water is supplied into the water storage container from the first pipe having a small inner diameter, the water flows into the water storage container. There is a problem that the mixing speed is high, the mixing ratio of warm water and water is large, and the water temperature is apt to drop significantly. In winter, it is impossible to prevent the water from freezing or to drain the water inside the water storage container for the purpose of cleaning the inside of the pipe.

An object of the present invention is to provide a vacuum solar heat collecting apparatus in which no air pool is formed inside a water storage container, and in which lot hot water can be collected and drained.

[0008]

SUMMARY OF THE INVENTION A vacuum solar heat collecting apparatus according to the present invention comprises a transparent long cylindrical glass container having both ends squeezed to a small diameter and an opening having both ends squeezed to a small diameter. A cylindrical metal water storage container which is disposed coaxially inside the glass container via a support member, has a selective absorption film coated on the outer surface thereof, and has an inner volume occupying 60% or more of the inner volume of the glass container. And a connection pipe penetrating each opening of the glass container and connected to each opening of the water storage container, and a sealing metal fitting for sealing each opening of the glass container, and the glass container and the water storage container There is a gap between the gaps, the gap is maintained in a vacuum, and each connecting pipe is connected to a header pipe located at both ends of the glass container.

Further, the vacuum solar heat collecting apparatus of the present invention is characterized in that a bellows is preferably formed on a part of the connecting pipe or the sealing fitting.

[0010]

In the present invention, the cylindrical metal water storage container disposed inside the glass container has an outer diameter larger than the small-diameter opening of the glass container and smaller than the inner diameter of the glass container. Since it is large enough to occupy at least 60% or more of the internal volume, a large amount of water is stored therein. The solar heat transmitted through the transparent glass container is collected in the water storage container via the selective absorption film. The heat collected in the water storage container is prevented from heat loss by the vacuum heat insulating action, and keeps the water inside the water storage container warm. The water inside the water storage container is heated by the solar heat, and the portion whose specific gravity is reduced moves upward inside the water storage container, so that a natural circulation occurs inside the water storage container, and the entire temperature is raised.

Further, when a bellows is formed in a part of the connecting pipe or the sealing fitting, thermal stress generated between the water storage container and the glass container is relieved, so that it is possible to suppress a vacuum deterioration at a connection portion between the two. .

When the vacuum solar heat collecting apparatus of the present invention is used, one header pipe is installed on a roof or a roof of a building so that one header pipe is higher than the other header pipe, and the upper or lower header is installed. By connecting one end of the pipe to a water supply pressure source such as a water supply via a pressure-reducing check valve, it is possible to fill the inside of the water storage container with water without forming an air pocket.

When one end of the lower header pipe is connected to a hot water supply pipe having a hot water tap and hot water is taken out of the water storage container, the supply of water from the water supply header pipe is stopped, so that the lot hot water can be collected. It becomes possible. In this case, after the hot water inside the water storage container is taken out, water is newly supplied from the water supply header tube into the water storage container. Usually, an automatic air vent valve or the like is attached to one end of the upper header tube in order to control the flow of air inside the water storage container.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a vacuum solar heat collecting apparatus of the present invention will be described in detail based on embodiments.

FIG. 1 is a longitudinal sectional view showing a vacuum solar heat collecting apparatus according to the present invention.

The glass container 1 has an opening 1 formed in advance.
The ends of two glass caps 1b having a are welded to both ends of a transparent long cylindrical glass tube 1c, and the opening 1a of the glass cap 1b is larger than the outer diameter of the main body of the glass tube 1c. It has a small diameter. The material of the glass cap 1b is the same as the glass tube 1c or the glass tube 1c.
Any material may be used as long as it has a thermal expansion coefficient close to that of the above and can be welded without hindrance.

The glass sealing member 2 is made of a cylindrical metal which can be sealed well with the glass container 1. For example, when the glass container 1 is made of soda-lime glass, 42% Ni-6% C
In the case of r steel and borosilicate glass, it is made of a Kovar alloy. One end of the glass sealing fitting 2 has a coefficient of thermal expansion close to that of the connecting pipe 3 and is welded or brazed so as to cover one end of the intermediate sealing fitting 4 made of metal having excellent corrosion resistance. The other end has an opening of the glass container 1 sealed at the other end. Further, the other end of the relay sealing fitting 4 is welded or brazed to the connecting pipe 3. The sealed portion is, of course, sufficiently free of distortion.

If the glass sealing member 2 is made of the same metal as the connecting pipe 3 or a metal having substantially the same thermal expansion coefficient, the relay sealing member 4 is not necessarily required. The connection pipe 3 can be sealed.

The water storage container 5 is made of a metal such as copper, stainless steel, iron, or the like, is fitted with a metal cylindrical body 5b having openings 5a at both ends, and is fitted to both ends of the cylindrical body 5b, and is welded all around. It is composed of two metal cap bodies 5c which are brazed circumferentially. The cylindrical body 5b and the cap body 5c may be made of the same material or different metals having the same or similar thermal expansion coefficients as long as they do not hinder the joining. The water storage container 5 has such a large volume that it occupies at least 60% of the internal volume of the glass container 1, and its outer surface is coated with a selective absorption film (not shown). And a gap is provided between them, and the gap is maintained at a predetermined degree of vacuum [for example, 10 ^-4 Torr]. In order to evacuate the inside of the glass container 1, an exhaust pipe is provided at an end of the glass container 1 or a part of the joint sealing fitting 4, and after evacuating therefrom, sealing is performed by welding or brazing.

One end of each connecting pipe 3 is attached to the opening 5a at both ends of the water storage container 5, and the other end of each connecting pipe 3 is brazed and inserted into the upper header pipe 6 or the lower header pipe 7. Alternatively, they are connected using a connection tool. A bellows 3a is formed in a part of each connecting pipe 3, and the bellows 3a relieves thermal stress generated between the water storage container 5 and the glass container 1. Supports 8a and 8b are attached to the center portions of the cap body 5c and the cylindrical body 5b constituting both ends of the water storage container 5, respectively. The supports 8a, 8b
It is used for supporting the water storage container 5 coaxially inside the glass container 1 while allowing thermal expansion and contraction. Providing the small-diameter outer peripheral portions 5d at both ends of the water storage container 5 ensures the stable support of the water storage container 5 inside the glass container 1 by the support tool 8a, and at the same time, the water storage container 5 in a portion other than the mounting portion of the support tool 8a. It is useful for increasing the storage volume of water.

The support member 8a is formed by bending an elastic metal wire into a convenient shape, for example, a substantially W shape, and uses two symmetrical members so as not to damage the inner surface of the glass container 1. Point contact. The support 8b includes a coil spring portion and a plate spring portion, and forms a fixed interval between the water storage container 5 and the glass container 1 by the coil spring portion.

The above-mentioned vacuum solar heat collecting apparatus is installed at a predetermined angle on the roof of a building or the like, and the water supplied from the upper header pipe 6 by opening the water supply valve is used for the upper connecting pipe 3. After flowing into the water storage container 5 through the tub and being drawn for a certain period of time until it is warmed up, the hot water tap is opened and taken out from the lower header pipe 7 through the lower connecting pipe 3 as hot water. Thereafter, the same amount of water as the amount of hot water taken out is transferred from the upper header pipe 6 to the upper connecting pipe 3.
Is supplied to the inside of the water storage container 5.

The supply and removal of water in the vacuum solar heat collecting apparatus of the present invention is not limited to the above method. For example, water is supplied from one end of the lower header pipe 7 into the water storage vessel 5. However, it is also possible to take out hot water from the other end of the same header tube 7. In that case, the upper header tube 6 functions as a drain port in the case of air bleeding and overflow.

Next, FIG. 2 shows an embodiment of a hot water supply system in which the above-mentioned vacuum solar heat collecting apparatus of the present invention is made up of four units as one unit, and two units are connected and installed on the roof 9 of a building. It is a schematic perspective view shown.

In FIG. 2, each vacuum solar heat collector is connected in parallel to an upper header tube 6 and a lower header tube 7. The upper header pipe 6 is connected to a water supply pressure source such as a water supply via a water supply pipe 12 provided with a pressure-reducing check valve 10 and a water supply valve 11. The water pressure from the pressure source is reduced to an appropriate pressure through the pressure reducing check valve 10 and acts on the entire hot water supply facility. For example, the water pressure of the tap water in Japan is maintained at a predetermined value [e.g., 3 kg / cm ² ], and this is adjusted to an appropriate pressure [e.g., 0.8 kg / cm ² ] by the pressure-reducing check valve 10.
It is used after adjusting the pressure.

The lower header pipe 7 is connected to a hot water supply pipe 14 having a hot water tap 13, and the hot water tap 13 is branched and disposed in a bathroom 15, a kitchen 16 and the like. The upper header pipe 6 is provided with a relief valve 17 and an automatic air release valve 18. Further, a drain pipe 19 and a drain valve 20 are provided in the middle of the water supply pipe 12.

The method of using the hot water supply equipment shown in FIG. 2 is as follows.

First, the drain valve 20 and the hot water tap 13
Is closed, and the water supply valve 11 is opened. As a result, water flows from the water supply pressure source such as the water supply through the pressure reducing check valve 10 and flows into the upper header pipe 6 from the water supply pipe 12,
Each water storage container 5 distributed from the upper header pipe 6 to each connection pipe 3 connected thereto and located inside each glass container 1
To the hot water supply pipe 14 are filled with water. Air from each water storage container 5 to the hot water supply pipe 14 is discharged from the automatic air vent valve 18 through the lower header pipe 7. At this time, the pressure in the hot water supply facility is maintained at a predetermined pressure set by the pressure reducing check valve 10. If left in this state for a while, the water in each water storage container 5 is heated by the solar heat passing through each glass container 1 and heating each water storage container 5 through the selective absorption film,
Natural circulation inside. When the water supply valve 11 is closed and the hot-water tap 13 is opened in a state where the water has become sufficiently hot water, the hot water in each water storage container 5 is taken out while suctioning the air from the automatic air vent valve 18. After the removal of hot water is completed,
Is closed and the water supply valve 11 is opened, the same amount of water as the amount of hot water taken out is supplied into each water storage container 5 from a water supply pressure source such as tap water.

When the water may freeze in winter or when cleaning the inside of the pipe, the water supply valve 11 is closed and the hot water tap 13 and the drain valve 20 are opened to open the inside of each water storage container 5 and the inside of the pipe. It is possible to drain the water.

[0030]

According to the vacuum solar heat collecting apparatus of the present invention, no air pocket is formed inside the water storage container, a large amount of water can be heated at a time, and new water flows into the water storage container. It is possible to take out hot water at the same time, so-called hot water collection, so that the temperature of the water does not drop due to the mixing of the hot water and the water, and also to prevent freezing and drainage for cleaning the inside of the piping. Can be easily performed.

Further, by forming a bellows on a part of the connecting pipe or the sealing fitting, thermal stress generated between the water storage container and the glass container can be reduced.

Further, in the present invention, in addition to the above effects, since the water storage container is made of metal, it is free from damage due to thermal shock, can be lightweight and can maintain the required pressure resistance, and can be made of a glass container and a metal water storage container. Because the opening end of the container is narrowed to a small diameter, the sealing area of the opening end of the glass container is reduced by the sealing metal, the probability of internal vacuum leakage is greatly reduced, and an expensive glass sealing metal The diameter of the metal part having a higher thermal conductivity than glass can be reduced, and the heat loss from the sealing metal can be reduced, and the lighting part can be widened by increasing the size of the transparent glass part. Therefore, there is also an effect that the heat collection efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a vacuum solar heat collecting apparatus of the present invention.

FIG. 2 is a schematic perspective view showing an embodiment of a hot water supply facility using the vacuum solar heat collecting apparatus of the present invention as a unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass container 2 Glass sealing fitting 3 Connecting pipe 3a Bellows 4 Intermediate sealing fitting 5 Water storage container 6 Upper header pipe 7 Lower header pipe 8a Supporting tool 8b Supporting tool 12 Water supply pipe 14 Hot water supply pipe

Claims (2)

(57) [Claims] 1. A transparent long cylindrical glass container having both ends narrowed and opened to a small diameter, and both ends narrowed and opened to a small diameter, and coaxially disposed inside the glass container via a support. A cylindrical metal water storage container having an inner volume occupying 60% or more of the inner volume of the glass container having a selective absorption film coated on the outer surface thereof, and a water storage container penetrating through each opening of the glass container. A connection pipe connected to each opening and a sealing fitting for sealing each opening of the glass container are provided, and a gap exists between the glass container and the water storage container, and the gap is evacuated to a vacuum. A vacuum solar heat collecting apparatus, wherein the connection pipes are held and connected to header pipes located at both ends of a glass container. 2. The vacuum solar heat collecting apparatus according to claim 1, wherein a bellows is formed on a part of the connecting pipe or the sealing fitting.