JPS5929791B2 - solar heat collector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION An object of the present invention is to provide a solar heat collector that has an extremely high heat collecting effect.

BACKGROUND ART In recent years, the amount of energy consumed has rapidly increased due to the remarkable development of industry and the sophistication of life, and there has been a rapid increase in awareness of the finite nature of energy sources on earth, which were previously thought to be infinite.

As a result, the use of solar energy as thermal energy has become popular as a pollution-free and inexhaustible energy source.

Typically, sunlight is absorbed onto a black plate to convert the solar energy into thermal energy, and the heat is transferred to a heat medium such as water to provide hot water and space heating.

In order to increase these heat collection efficiencies, it is an important technical point to lower the reflectance of the black coating to light and increase the absorption coefficient.

On the other hand, these heat collecting plates have a large specific surface area relative to the outside world, and are considered to constitute a heat radiator relative to the surroundings.

Therefore, reducing the heat dissipation of the collected heat to the outside world is more important in this field of technology than the technology of increasing the absorption efficiency of the sagi.

Heat dissipation from heat collecting plates can be divided into several forms, but
One of them is based on radiation from the surface of the heat collecting plate.

More than 90% of the energy of sunlight is distributed between wavelengths of 400 mμ and 2μ.

The heat collecting plate absorbs this energy, and when the temperature begins to rise, it emits infrared rays with a spectral distribution determined by the temperature.

When the temperature is around 100° C., which is normally used for hot water supply, heating, and cooling, the radiation infrared rays spread to a wavelength range of 3 μ or more.

One known method for preventing heat radiation is to attach a selective absorption film to the surface of the heat collector plate that has high absorption of sunlight and low radioactivity for light with wavelengths of 3μ or more. .

Another form of heat dissipation from the heat collector plate is through air convection present on the heat collector plate surface.

To prevent this, an air layer is placed on the heat collector plate, and a transparent cover made of glass or plastic is installed to cut off the air flow between the air on the heat collector plate and the outside air, and the air layer is used as a thermal insulation layer. There are currently known methods that can be used as such.

In view of the above-mentioned prior art, the present invention provides a solar heat absorber that has a large heat collection effect and a small heat dissipation.

The details of the present invention will be explained below along with several examples.

FIG. 1 shows the overall structure of a solar heat collector based on the present invention.

In FIG. 1, numeral 1 is an iron plate having a selective absorption film on its surface, and numeral 3 is a cloth iron plate.

The iron plate 1 and the iron plate 3 are partially bonded together and have a water channel 2 on one side through which hot water flows, forming a heat collecting plate 4.

7 is a box-shaped container with a bottom plate 8 and an open top.

A glass 12 is attached to the upper part of the box-shaped container γ, and the glass 12 is integrated with the box-shaped container 7 with a presser fitting 5 and screws 6.

9 is a heat insulating material provided between the heat collecting plate 4 and the bottom plate 8.

A transparent plastic film 13 is attached to the side plate of the box-shaped container 7 to further prevent wear and tear, and is the most important point of the present invention.

In the above heat collector, characteristics were compared using various transparent plastic films 13 having refractive indexes as shown in Table 1.

FIG. 2 is a heat collection characteristic diagram based on heat collection temperature, outside air temperature, amount of solar radiation, and heat collection efficiency.

In Figure 2, Ti is the heat collection temperature °C, and TA is the outside air temperature °C1.
is the amount of solar radiation kcbt/77Z2h.

It can be seen from FIG. 2 that the refractive index has a significant effect on the heat collection efficiency, and that the efficiency is particularly improved when the refractive index is about 1.45.

As described above, the present invention clarifies the mechanism of heat dissipation in solar heat collectors. In other words, in solar heat collectors using heat collecting plates with an excellent selective absorption film, the ratio of heat dissipation by convection is extremely large. The purpose of the present invention is to provide a solar heat collector with a structure that has a large heat collection effect.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of a solar heat collector according to an embodiment of the present invention, and FIG. 2 is a heat collection characteristic diagram when various glass films are used in the configuration of FIG. 1. 1.3... Iron plate, 2... Waterway, 4...
...heat collecting plate, 5...presser metal fitting, 6...
... Screw, 1 ... Box-shaped container, 8 ... Bottom plate, 9 ... Heat insulation material.

Claims (1)

[Claims] 1. A heat collecting plate that receives sunlight and converts solar energy into heat, a glass plate that covers the heat collecting plate with a space in between, and a container that is integrated with the glass plate and houses the heat collecting plate inside. In a solar heat collector having a heat insulating material between the heat collecting plate and the container, a layer of organic glass film is present between the heat collecting plate and the glass plate, and the light refraction of the organic plastic film is A solar heat collector with a rate of approximately 1.45 or less.