JPS6015068Y2 - Vacuum tube solar collector - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a vacuum tube type solar heat collector.

Various proposals have been made regarding the structure of the heat collecting part in conventional vacuum tube type solar heat collectors, but as shown in FIG.
A flat heat receiving plate 3 (not shown, but there is also a curved heat receiving plate 3) fixed thereon is used.

In this case, in order to capture the sunlight that has entered the vacuum tube 1 without wasting it, the area of the heat receiving plate 3 may be increased, but this method is not preferable because it also increases the heat radiation area.

Therefore, as a countermeasure to this problem, we adopted a method of concentrating sunlight using a reflector to reduce the heat receiving area.
There is also a proposal to use a reflector plate 4 having a compound paraboloid (not shown) or a compound involute surface that combines true line parts on both sides of the involute curve of the heat collecting tube 2 as shown in FIG. In the case of the reflector, there is a range of incident angles in which light cannot be focused, which limits the operation time of the heat collector, making it difficult to put it into practical use.

The object of the present invention is to provide a vacuum tube type solar collector that does not have the above-mentioned drawbacks.

The present invention is a vacuum tube type solar collector consisting of a vacuum tube in which a reflector is provided at the bottom of the tube, and two collector tubes are horizontally arranged above the reflector, either independently or connected at one end. The present invention relates to a vacuum tube type solar heat collector, wherein the reflecting plate has a cross-sectional shape consisting of an involute curve starting from below the center of each heat collecting tube and expanding and opening on both sides.

The present invention will be explained below with reference to the drawings.

FIG. 3 is a plan view of a vacuum tube type solar collector according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along line A-A in FIG. , 5 protrude outside the vacuum tube 1 and connect to the header 7.

Reference numeral 6 denotes a reflector whose cross-sectional shape consists of an involute curve of the heat pipes 5, 5.

In other words, it is an involute curve that extends and opens from the bottom of the center of the heat pipes 5, 5 to both sides of the heat pipes 5, 5, or is connected by a connecting part 6b. In this case, if the outer diameter of the heat pipe 5 is D, then one What is the maximum opening width of the involute curve of heat pipe 5? It becomes rD and 2 for 2? Since it is rD, the inner diameter of the glass tube (vacuum tube 1) is also 2? rD is required.

Note that the protrusions 6a, 6a of the reflector 6 below the center of the heat pipes 5, 5 are for the purpose of thermal insulation.
It is necessary to separate it slightly from 5.

Further, as described above, there may be no connection portion 6b and there may be some gap.

FIG. 5 shows another embodiment of the present invention, in which a U-shaped water-flowing type heat collecting tube 8 is housed in the vacuum tube 1, and a water-flowing port 8ay8 at the other end.
b is connected in series with a heat collecting tube of another vacuum tube (not shown) outside the vacuum tube 1 to form a vacuum tube type solar heat collector.

The reflection plate 6 in the vacuum tube 1 in this case has the same structure as in the above case.

Also, although FIG. 6 shows a water-flow type heat collector tube 9 with a double tube structure of an outer tube 9a and an inner tube 9b, other vacuum tube type solar heat collectors can be constructed by combining this with the above-mentioned reflector 6. Can be done.

Vacuum tube type heat collectors have the advantage of being used at high temperatures because they have less convection loss due to vacuum insulation.

However, at high temperatures, radiant heat radiation increases, so it is better to make the area of the heat collecting part as small as possible.

That is, the ratio U/R between the light receiving area U and the heat radiation area R is generally referred to as a light collection ratio, and the larger this value, the higher the efficiency of the heat collector.

In the case of having the conventional flat heat receiving plate shown in Fig. 1, if the width of the heat receiving plate is F1 and the outer diameter of the heat collecting tube is D, then U 1 wD , the light collection ratio is R”2,000 F, which is a value of 0.5 or less. becomes.

On the other hand, in the case of the present invention, an involute reflector is used, and the maximum opening width of the reflector is 2? Since it is rD, the condensing ratio is 1.

Therefore, the heat radiation area for the same light receiving area is less than half that of the case shown in FIG.

Furthermore, unlike the case of FIG. 2, all incident light can be collected into two heat collecting tubes regardless of the incident angle.

In this way, according to the present invention, two heat collecting tubes and a reflector whose cross section is the involute curve of the two heat collecting tubes are housed inside the vacuum tube, so even if the incident angle of sunlight changes, all incident light will be reflected. Since the heat medium can be heated by collecting light in the heat collecting tube, there are advantages such as being able to heat the heat medium to a high temperature without any restriction on operating time.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the vacuum tube of a conventional vacuum tube solar collector, Figure 2 is a cross-section of the vacuum tube of another conventional vacuum tube solar collector, and Figure 3 is an embodiment of the present invention. A plan view of a vacuum tube type solar heat collector, FIG. 4 is a sectional view taken along the line A-A in FIG. 3, FIG. 5 is a plan view of a vacuum tube type solar heat collector according to another embodiment of the present invention, and FIG. FIG. 3 is a partially cutaway plan view of a heat collecting pipe according to another embodiment. Explanation of symbols: 1... Vacuum tube, 2... Heat collecting tube, 3... Heat receiving plate, 4... Reflector plate,
5...Heat pipe, 6...Reflector,
6a...Protrusion part, 6b...Connection part, 7
...Header, 8... Heat collection pipe, 8a,
8b... Water inlet, 9... Heat collecting pipe, 9a
...Outer pipe, 9b...Inner pipe.

Claims (1)

[Claims for Utility Model Registration] 1. Vacuum tube type solar thermal heat generating system consisting of vacuum tubes with a reflective plate installed at the bottom of the tube and two heat collecting tubes horizontally arranged above the reflective plate, each independent or connected at one end. A vacuum tube type solar heat collector, wherein the reflective plate has a cross-sectional shape consisting of an involute curve that starts from below the center of each heat collector tube and expands and opens on both sides. 2. The vacuum tube type solar heat collector according to claim 1, wherein the heat collecting tube is a heat pipe.