JPS595808B2 - solar heat collector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solar heat collector used in a solar heat utilization system.

This type of solar heat collector generally includes a glass container formed by a glass tube hermetically closed with an end cap.

This glass container accommodates a heat collection pipe that hermetically passes through the end cap, and its interior is evacuated to create a high vacuum.

Further, a heat collecting reflector is arranged outside the glass container, and this reflector is configured to collect sunlight onto the heat collecting pipe.

Therefore, in such a device, sunlight is focused on a heat collecting pipe using a heat collecting reflector plate to heat the pipe, and this heat is used to heat a heat medium flowing into the heat collecting pipe.

Further, since a heat insulating layer formed by a vacuum space is formed inside the glass container, heat dissipation from the heat collecting pipe is prevented.

Therefore, the heat of this heat collecting pipe is well conducted to the heat medium, so the heat collecting performance of this device Q is high.

Therefore, in such a device, a support member is disposed within the glass container.

This support member is fixed to the heat collecting pipe at its center, and its outer edge abuts against the inner surface of the glass container, that is, the glass tube, thereby holding the heat collecting pipe on the tube axis of the glass container.

However, since this support member conducts the heat from the heat collecting pipe to the glass tube, there is a problem in that the glass tube is locally heated and the glass tube is damaged due to the thermal expansion.

In order to eliminate such problems, it may be possible to interpose a poor thermal conductor made of synthetic resin or the like with poor thermal conductivity between the heat collecting pipe and the support member or between the support member and the glass tube. .

However, when evacuating the glass container, it is necessary to perform a deaeration process during the evacuation process, and this deaeration process requires 400% of the glass container, heat collecting pipe, support member, and other components.
By heating to about .degree. C., impurities such as moisture attached to or occluded in these components are released into the glass container and evacuated.

Therefore, in order to perform this degassing treatment, the components inside the glass container must be heat resistant to high temperatures of about 400°C.

However, when the poor thermal conductor is made of synthetic resin or the like, the heat resistance of the poor thermal conductor is insufficient and the degassing treatment cannot be carried out.

For this reason, during use of the device, impure gas generated within the glass container lowers the degree of vacuum, resulting in a problem that the heat collection performance deteriorates.

In addition, when holding the heat collection pipe to the glass tube using a support member, if they are tightly connected, thermal distortion will occur in the glass tube due to the difference in thermal expansion between the heat collection pipe and the glass tube, easily causing damage such as cracks. .

Another disadvantage is that the glass tube is easily damaged when external shocks or vibrations are applied.

This invention was made based on the above circumstances, and its purpose is to prevent local heating of the glass tube by reducing the amount of heat conducted from the heat collecting pipe to the glass tube. In addition, it has enough heat resistance to withstand the heat during degassing process, making this degassing process possible.
It is an object of the present invention to provide a solar heat collecting device that can maintain the degree of vacuum in a glass container, and can further absorb thermal distortion, impact, etc., and prevent cracks and damage.

That is, the present invention is characterized in that a poor thermal conductor made of a heat-resistant cushion material is interposed between the heat collecting pipe and the support member.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

1 in the figure is a glass container, and this glass container 1 has a glass tube 20 at both ends with metal end camps 3a, 3b.
It is configured to be airtightly closed.

The glass tube 2 is made of hard glass, and in this embodiment has a diameter of 120 mm and a total length of 3000 mm.
A certain amount is used.

Further, the end caps 3a and 3b are made of a metal having approximately the same coefficient of linear expansion as the above-mentioned hard glass.

Inside the glass container 1 is an end cap 3a.

A heat collecting pipe 4 is disposed that passes through the heat collecting pipe 3b in an airtight manner.

The heat collecting pipe 4 constitutes a passage for a heat medium, and is made of a copper pipe or the like having excellent thermal conductivity.

Further, the heat collecting pipe 4 has an end cap 3a.

3b in an airtight manner, and one end cap 3a is hermetically penetrated through a joint pipe 5 as shown in FIG.

This joint pipe 5 has a double pipe structure with the heat collecting pipe 4, and one end is hermetically joined to the end cap 3a, and the other end is hermetically joined to the outer surface of the heat collecting pipe 4.

Further, the joint pipe 5 is composed of a stainless steel bellows 6, and this bellows 6 absorbs the difference in thermal expansion between the heat collecting pipe 4 and the glass container 1.

Further, an exhaust pipe 7 is connected to the other end cap 3a.

This exhaust pipe 7 is connected to a vacuum pump when evacuating the inside of the glass container 1, and is sealed when the inside of the glass container 1 reaches a predetermined high degree of vacuum.

A support member 8 having a circular shape, for example, is disposed within the glass container 1 .

This support member 8 is formed of a heat-resistant metal or an inorganic sintered body, and is attached to the heat collecting pipe 4 via a poor heat conductor 9 made of a heat-resistant cushioning material.

The support member 8 holds the heat collecting pipe 4 on the tube axis of the glass tube 2, that is, the glass container 1, by having its peripheral edge abutted against the inner surface of the glass tube 2.

The poor heat conductor 9 is constituted by a metal mesh made of stainless steel wire, and is interposed between the support member 8 and the heat collecting pipe 4.

Further, a getter 10 is disposed within the glass container 1.

The getter 10 has a ring shape and is attached to the heat collecting pipe 4 via a poor thermal conductor 11 having the same structure as the poor thermal conductor 9.

Further, when the getter 10 evacuates the inside of the glass container 1, it forms a vapor deposited film 12 made of barium or the like on the inner surface of the glass tube 2 by high-frequency heating during the degassing process performed during the evacuation process. This device adsorbs and removes impurity gases generated in the glass container 1 during use of the device.

Such a glass container 1 is installed with the heat collecting pipe 4 supported on support stands 13, 13, and a heat collecting member such as a heat collecting reflector plate 1 is provided on the outside of the glass container 1.
4 is placed.

The heat collecting reflector plate 14 is formed with a curved reflecting surface 14a on the surface facing the sun, and sunlight reflected on this reflecting surface 14a. The light is configured to be focused on the heat collecting pipe 4.

Further, the heat collecting reflector 14 has arm members 15, 15 on both end sides.
It is attached to the heat collecting pipe 4 via the heat collecting pipe 4, and is configured to be rotatable around the heat collecting pipe 4.

The rotation of the heat collecting reflector plate 14 is controlled by a tracking mechanism 16.

That is, the tracking mechanism 16 includes a rack 17 provided on the back surface of the heat collecting reflector 14 and a pinion 18 that meshes with the rack 17.

The pinion 18 is connected to a motor (not shown) capable of forward and reverse rotation, and by controlling the rotation of the pinion 18 with this motor, the heat collecting and reflecting plate 14- is rotated to follow the movement of the sun. It is configured to allow

Further, a selective absorption film 19 is formed on the surface of the heat collecting pipe 4 inside the glass container 1 .

This selective absorption film 19 has the property of absorbing well the wavelength range of sunlight focused on the heat collecting pipe 4 and emitting only a small amount of radiation in the infrared wavelength range.

Next, the operation of an embodiment with such a configuration will be explained.

First, when the rotation of the heat collecting reflector plate 14 is controlled by the tracking mechanism 16 according to the movement of the sun, the sunlight reflected by the reflecting surface 14a passes through the glass container 1 and passes through the heat collecting pipe 4.
The light is focused on.

Since the selective absorption film 19 is formed on the surface of the heat collecting pipe 40, it can absorb wavelengths of sunlight well and prevent emission of infrared wavelengths.

Therefore, the heat collecting pipe 4 is heated and its temperature increases.

The heat of the heat collecting pipe 4 is conducted to the heat medium flowing into the heat collecting pipe 4 and heats the heat medium.

In addition, during such a heat collecting action, since the inside of the glass container 1 is configured as a heat insulating layer due to the vacuum space, the heat collecting pipe 4
heat dissipation from the

Therefore, the heat of the heat collecting pipe 4 is well conducted to the heat medium, so that the heat collecting efficiency is high.

According to this embodiment, since the poor thermal conductor 9 is made of a metal mesh made of stainless steel wire, the poor thermal conductor 9 can sufficiently withstand high temperatures of about 400°C.

Therefore, when evacuating the inside of the glass container 1, it is necessary to heat the glass container 1, the heat collecting pipe 4, the support member 8, the defective heat conductors 9 and 11, etc. to a high temperature during the evacuation process to perform deaeration treatment. can.

Therefore, the degree of vacuum within the glass container 1 can be maintained for a long period of time, and the heat collection performance of the device can be prevented from being degraded.

Further, since the getter 10 is provided inside the glass container 1, the degree of vacuum inside the glass container 1 can be maintained more reliably.

Furthermore, since the poor thermal conductor 9 is made of a metal mesh, the contact area between the poor thermal conductor 9 and the heat collecting pipe 4 and the heat conduction area of the poor thermal conductor 9 are extremely small.

Therefore, the amount of heat conducted from the heat collecting pipe 4 to the support member 8 via the poor heat conductor 9 can be reduced.
The glass tube 2 is not locally heated to a high temperature.

As a result, local thermal expansion occurring in the glass tube 2 can be suppressed, and damage to the glass tube 2 can be prevented.

Furthermore, since the poor thermal conductor 9 is made of a metal mesh, it has elasticity.

As a result, the poor heat conductor 9 is connected to the heat collecting pipe 4 and the support member 8.
The difference in thermal expansion between the support member 8 and the glass tube 2 can be absorbed by the elasticity described above.

Furthermore, even if a mechanical impact is applied during use of the device, this impact is absorbed by the elasticity of the poor thermal conductor 90, thereby further increasing the reliability of the device.

Note that the present invention is not limited to the above embodiment.

For example, the poor thermal conductor is not necessarily composed of a metal mesh, but may be composed of a heat-resistant cushioning material such as glass fiber.

Further, the support member is not limited to a circular support member, but may be a triangular support member 50 as shown in FIG. A support member 60 configured to abut against the inner surface of the tube 2
Furthermore, as shown in FIG. 6, the support member 70 may use linear springs 79a and 7Qa.

Further, the heat collecting member is not limited to a heat collecting reflector placed outside the glass container, but the heat collecting reflector may be placed inside the glass container.

Further, instead of the heat collecting reflector plate, a heat collecting plate connected to the heat collecting pipe may be used, and when this heat collecting plate is used, a supporting member is attached to the heat collecting plate, and the heat collecting plate is The poor heat conductor may be interposed between the support member and the support member.

As explained above, the present invention is characterized in that a poor thermal conductor made of a heat-resistant cushioning material is interposed between the support member and the heat collecting pipe.

Therefore, when the inside of the glass container is evacuated, even if the glass container is heated and degassed during the evacuation process, the poor thermal conductor is heat resistant and will not undergo thermal deterioration, thus ensuring good evacuation. Air treatment can be performed and a high degree of vacuum can be maintained.

As a result, the degree of vacuum within the glass container can be maintained over a long period of time during the use of the device, and a decrease in the heat collection performance of the device can be prevented.

Furthermore, since the poor thermal conductor is a poor thermal conductor, the amount of heat conducted from the heat collecting pipe to the support member can be reduced, and local heating of the glass tube can be suppressed.

Therefore, damage to the glass tube caused by local thermal expansion of the glass tube can be prevented.

Furthermore, since the poor thermal conductor is made of a cushioning material, it absorbs the difference in thermal expansion between the glass tube and the heat collecting pipe, and also absorbs shock and vibration, preventing cranking and damage to the glass tube. The effect is great as it can be prevented.

[Brief explanation of the drawing]

Figures 1 to 3 show one embodiment of the present invention.
The figure is an overall view of the apparatus, FIG. 2 is an enlarged sectional view of the section ``■'' in FIG. 1, and FIG. FIGS. 4 to 6 show other embodiments of the present invention, and are perspective views showing other supporting members, respectively. 1...Glass container, 4...Heat collecting pipe fume 8...Supporting member, 9...Poor heat conductor, 14...Collection Heat reflecting plate (heat collecting member).

Claims (1)

[Scope of Claims] 1. A glass container in which the end of a glass tube is hermetically closed with an end cap and the inside is evacuated to create a high vacuum, and the end cap is hermetically passed through the glass container. a heat collecting pipe disposed as a heat carrier and forming a passage for a heat medium; a heat collecting member provided outside or inside the glass container for heating the heat collecting pipe by collecting solar heat; A supporting member is provided to support the heat collecting pipe on the glass tube, and between the supporting member and the heat collecting pipe, a poor heat conductor made of a heat resistant cushioning material such as a metal mesh or heat resistant glass fiber is provided. A solar heat collecting device characterized by having a body interposed therein. 2. The solar heat collecting device according to claim 1, wherein the heat collecting member is constituted by a heat collecting reflection plate disposed outside the glass container.