JPS5883168A - Radiational cooler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation cooler, and more particularly to a radiation cooler that cools an object by utilizing heat radiation.

Conventionally, Kunkin cycle type coolers that utilize the condensation and expansion of steam have been widely used.

However, such Rankine cycle type coolers require energy to operate the device, and a lot of loss occurs when converting this energy1.As a result, energy usage efficiency is poor and cooling costs are high. It had the disadvantage of being expensive. Especially for coolers that use electric energy, cooling costs tend to increase year by year as the oil situation worsens.
Furthermore, since such a Rankine cycle type cooler has many energy conversion steps, the entire device becomes complicated and large, and the equipment cost becomes high.

Therefore, it has been desired to develop a cooler that uses a cheap energy source, has a simple and inexpensive structure, and has excellent cooling ability.

First, a theory that would make it possible to provide such a cooler was proposed by A.K.-Head of Australia. This theory performs radiative cooling by focusing on the three modes of heat transfer: radiation, convection, and conduction.

Figure 1 shows a cooler based on this theory3.
This cooler includes a box-shaped insulating container 10 that insulates the object from the outside except for a part of the object to be cooled, and a heat radiator installed inside the insulating container 10 toward an opening. body 1
The opening e of the heat insulating container IO is provided with a cover 16 that transmits radiation, and the heat radiator 12 is in contact with a cooled body (not shown).

The heat radiator 12 is radiatively cooled by the exchange of radiation light between the heat radiator 12 inside the cooler and the outside of the cooler through the cover 16. Cools the object to be cooled connected to the transmission line 4.

By the way, from the outside 2 of the cooler to the radiation surface 1 of the heat radiator 12
The external light incident on 4 includes solar radiation 100 from the sun and thermal radiation 200 from the atmosphere, and on the other hand, the radiation emitted from the inside of the cooler to the outside depends on the temperature of the radiation surface 14. There is a thermal radiation 300. Therefore, in order to cool the object to be cooled by the radiation cooling described above, solar radiation of 10
It is necessary that the amount of heat released to the outside of the cooler by the heat radiation 300 from the radiation direction I4 is greater than the amount of heat input into the inside of the cooler by the heat radiation 200 and the radiation direction I4.

FIG. 2 shows each synchrotron radiation transmitted and received by the radiation surface 14]00.2
The emission spectrum at 0f3.300 is shown. Here, the original energy of the thermal radiation 300 emitted from the radiation rl'+114 to the outside of the cooler changes depending on the temperature of the radiation surface 14, but when the temperature changes within the room temperature range where the cooler is used, the wavelength is always around 10 μm. 1, which can be regarded as having a peak at
The original energy of 00 is 8 to 13 Bm with a wavelength of around 10 μm.
There is a large drop in the specific α-long range of . Therefore, heat radiation 3 is emitted from the radiation direction 14 to the outside of the cooler.
The heat tit of 00 is larger than the amount of heat of the heat radiation 200 that enters the radiation #-1 surface 14 from the outside of the cooler.

Therefore, if the cooler shown in FIG. 1 is used at night when there is no solar radiation 100, the amount of heat released from the radiation 114 to the outside of the cooler is larger than the amount of heat that enters the radiation direction 14 from outside the cooler. Therefore, the heat radiator 121d is radiatively cooled, and the object to be cooled that is in conductive contact with the heat radiator 12 is also cooled.

In A., Head's theory takes this idea one step further;
．． The present invention aims to provide a radiation cooler that selectively reflects and absorbs 200.300 rays and has excellent cooling ability regardless of day or night. That is, in the radiation direction used in the cooler as shown in Fig. 1, the emissivity and absorption rate in the specific wavelength range of 8 to 13 μm must be within the wavelength range other than this critical wavelength range, that is, 8 no 110 or less. It also includes the use of a reflective surface (hereinafter referred to as a selective reflective surface) that has good reflectance in a wavelength range of 13 μm or more.

If a selective radiation surface is used as the radiation surface 14 of the cooler in this way, all of the 100 rays of solar radiation from the sun will be reflected on the reflective surface 14, and the conditions will be the same even during the day as at night when there is only 100 rays of solar radiation from the sun. . Therefore, the cooler will be sufficiently cooled day and night.

Furthermore, as is clear from the radiation spectrum shown in Figure 2,
If only solar radiation of 100 nm can be reflected, it is sufficient to limit the selectivity of the anti-#J surface 14 to a wavelength range of 4 μm or less. Nevertheless, according to Head's theory, the reflective surface 1
4 is required to have a high reflectance in a wavelength range other than 8 to 13 μI11 in order to increase the cooling capacity of the cooler.

That is, thermal radiation 2 (
) When comparing the amount of heat of 0 and the amount of heat of the heat radiation 300 released from the radiation direction 14 to the outside of the cooler, the total amount of heat radiation 300 released from the radiation direction 14 is superior, but it is less than 8 μIn. In the wavelength range of 13 μm and above, thermal radiation from the atmosphere is partially superior. Therefore, the synchrotron radiation 200.
By limiting the 300 spectrum to 8-13 μm VC, the difference in the total amount of heat entering and exiting the radiation 1114 can be increased to increase cooling capacity.

As a radiation cooler based on the theory of A, -K-Head, a radiation cooler provided by #1G-Tro-1θθ by A-W-Harrisoni is known.

FIG. 3 shows a radiant cooler proposed by A, W, Harrison et al. This radiation cooler is made of an aluminum plate 14a with a thickness of 6 mm in order to provide the radiation surface 14 of the heat radiator 12 with the aforementioned selective radiation.
6) T10 on the bridge surface. White paint containing 35% of
] 4b to form a radiation m1]4.

However, the reflective surface 14 T1. j, n1lk:
According to the theory of A+K''Heacl, almost no selectivity in a specific wavelength range could be expected, and the cooling efficiency of the radiation cooler was extremely low.

1. The radiation cooler proposed by G. Troise et al. coats the metal surface of an aluminum plate with a thin film of TPDi, AR (registered trademark) with a thickness of -J 12.5 μm, and then the radiation surface of the heat radiator 12 is 14 was formed. However, although the radiation surface 14 of this cooler exhibits a certain degree of selectivity for a specific wavelength range, it does not exhibit sufficient selectivity compared to the selectivity explained in the theory of A-K. Head. . Therefore, the cooler proposed by G-Troise has a low cooling capacity, and in particular, the reflectance of the radiation surface 14 to visible light is low, so the cooling ability during the day when 100% of solar radiation is incident on the radiation surface 14 is significantly reduced. was there.

Therefore, it has been desired to develop a cooler having excellent cooling ability based on the theory of A-[-Head.

The present invention was made in view of such conventional problems, and its purpose is to provide a heat radiator with sufficient selectivity to synchrotron radiation, and to exhibit excellent cooling ability day and night. The purpose of this project is to provide a radiant cooler that can be used as a river.

In order to achieve this object, an object to be cooled is introduced into the cooler of the present invention, and includes an insulating container that insulates the object from the outside except for a part of the object to be cooled, and a heat radiator that searches the exposed part of the insulating container. 11. The heat radiator includes a conductive layer made of a metal having high reflectance and thermal conductivity and in conductive contact with the object to be cooled, and a conductive layer coated with the conductive layer and containing a small amount of original energy contained in external light. 1-COCr 20t that has high emissivity (grain yield) in the wavelength range and high transmittance in other wavelength ranges
/ K2804 r 81314゜ / K2SO4 or 2-layer inorganic materials such as So, / K, So, or vinyl fluoride-vinylidene fluoride copolymer, polyoxyglobylene, vinylidene difluoride, polyglopylene and tetraboil and a selective radiation layer made of a single-layer organic material such as chemical copolymer, which absorbs the source energy of external light in the specific wavelength range and radiates heat from the object to be cooled, and also In the wavelength range, it is characterized by reflecting external light to cool the object to be cooled.

Next, what is the preferred fruit M of the present invention? ! I will be explained based on the drawings.

FIG. 4 shows one preferred embodiment of the present invention. The radiation cooler of the present invention has a heat insulating container 2 into which an object to be cooled (not shown) is introduced and which insulates the object from the outside except for a part.
0, and a heat radiator 22 that is in conductive contact with the object to be cooled inside the heat insulating container 20 and covering the exposed portion of the heat insulating container 20. In the embodiment, the heat insulating container 20 is formed into a box shape with one side open, and the heat radiator 22 is formed into a plate shape,
It is provided inside the heat insulating container 20 so as to cover the opening of the heat insulating container 20.

The characteristic feature of the present invention is that the thermal radiator 22 has selectivity in the specific wavelength range explained by Head's theory, that is, the selectivity of the 8 to 13 μm wavelength range, which has low optical energy contained in external light 100.200. The object is to provide high emissivity in a specific wavelength range and good selectivity in reflectance in the wavelength range of 8 μm or less and 13 μm or more, where the optical energy contained in external light 100.200 is high. Therefore, as shown in FIG. 5, the present invention includes a conductive layer 22a made of a metal having high thermal conductivity and high reflectance, which is in conductive contact with the VC1 cooling body, and CoCr, 0.
7/KtSO< + S'SN4/Kt"04'!
In addition, inorganic materials with a two-layer structure such as So, /K2SO4, or organic materials with a single-layer structure such as vinyl fluoride-vinylidene fluoride copolymers, polyoxypropylene, vinylidene difluoride t-polypropylene, or tetrafluoride copolymers. It is characterized in that the heat radiator 22 is formed of a selective radiation layer 22b made of a material and coated on the conductive layer 22a. This is due to the following reasons.

In other words, the reflectance of the conductive layer 22a is high for light in all wavelength ranges, and the selective emission layer 22a has a high reflectance for light in all wavelength ranges.
The inorganic material with the two-layer structure and the organic material with the phosphor layer structure that form b exhibit high emissivity for light in the wavelength range of 8 to 13 μm, and high transmittance for X and VC in the other wavelength ranges. Therefore, this heat radiator 22 has a thickness of 8 to 13 μm.
The selective radiation layer 22b absorbs the elements in a specific wavelength range, and the elements in other wavelength ranges are totally reflected by the gold-plated surface of the thermally conductive layer 22a. It shows emissivity and exhibits good reflectance for other wavelength ranges, that is, wavelength ranges of 8 μm or less and 13 μI11 or more.

In the VC of this embodiment, the heat conductive layer 22a has a thickness of 0.8 mm and a length of 1771 mm. It was formed using a mirror-finished aluminum plate with a width of 0.5 m, and selective radiation of 1 inch 22 b was
It is formed using Afflex Film (registered trademark) having a thickness of 25 μm, which is a type of vinylidene difluoride.

This Afflex film is coated onto the aluminum plate using electrostatic force.

FIG. 6 shows the spectral reflectance characteristics of the thermal radiator 220 of this embodiment formed using an aluminum plate and an Afflex film, and shows the specific wavelength range explained in the A-K-Head theory above. It is understood that the selectivity is excellent.

In addition, in the cooler of this embodiment, in order to make the insulation effect of the insulation container 20 equal to that of light, the insulation container 20 has a thickness of 50 mm.
It is made of polystyrene foam with a thickness of 0.5 mm, and an aluminum foil 24 with a thickness of 0.1 mm is coated on its inner surface to prevent the transfer of radiant heat from the container 20 to the heat radiator 22.

In addition, a cover holder 26 and a cap 28 are provided at the opening of the cooler to shield the outside air and improve the cooling effect.
is installed. This cover 28 is made of a polyethylene film with a thickness of 20 μm so as to be transparent to all wavelength ranges.

The present invention has the above-mentioned configuration, and its operation will now be explained.

When the radiation cooler of the present invention is actually used, as shown in FIG. Heat transfer due to heat conduction and air convection is considered1.
However, in the embodiment, the heat insulating container 20 has excellent heat insulating properties and the inner surface is coated with an aluminum plate 24 that prevents the transfer of radiant heat from the heat radiator 22. Thermal conduction tD, l
'L is almost a negligible value. , -1: Ta, cover 2
8, the inside of the cooler is shielded from the outside air, and when the table r&+ temperature of the heat radiator 22 is lower than the outside air pressure, the transfer of heat due to air convection becomes a negligible value. .

Therefore, when the radiation cooler of the present invention is installed outdoors, the heat radiator 22 receives and receives radiation based on the above-mentioned A-K.Head theory, and exhibits excellent cooling ability day and night. be done.

That is, in the radiation cooler of the present invention, its thermal radiator 22 exhibits spectral reflectance characteristics as shown in FIG.
It has a high emissivity in the wavelength range of ~13 μm.

Therefore, most of the solar radiation 100 from the sun that enters the heat radiator 22 from the outside of the cooler through the cover 28 is reflected by the heat radiator 22 because its wavelength is 4 μm or less. I'm in a trench.

Therefore, heat transfer into the cooler due to solar radiation 100 from the sun is ignored.

Also, the heat radiator 2 is inserted from the outside of the cooler through the cover 28.
Most of the thermal radiation 200 from the atmosphere that is incident on the thermal radiator 22 is reflected by the thermal radiator 22, and only the thermal radiation in the wavelength range of 8 to 13 μm with low optical energy is reflected by the thermal radiator 22.
In addition, heat radiation 300 corresponding to the surface temperature of the heat radiator 22 is emitted from the heat radiator 22 of the cooler, and is emitted to the outside of the cooler via the cover 28. here l
/(, since the emissivity of the thermal radiator 22Fi is high in the range of 8 to 13 μm, the thermal radiation 300 from the thermal radiator 22 is performed in the wavelength range of 8 to 131 tm, which has a large amount of light energy1. Therefore, this thermal radiation The heat transfer TJJh due to the synchrotron radiation transmitted and received by the body 22 includes the thermal radiation 200 from the atmosphere in the wavelength range of 8 to 13 μm, where the original energy is small, and the thermal radiation 200 in the wavelength range of 8 to 13 μm, where the original energy is large.
What is necessary is to consider the transfer of heat due to thermal radiation 300 from 2. Each of these thermal radiations in the wavelength range 8-13 μm 20
As shown in FIG. 2 (9j), the heat transfer due to 0.300 is overwhelmingly greater due to the heat radiation 300 from the heat radiator 22.

Therefore, in the radiation cooler of the present invention, more heat sink enters from outside the cooler and goes out to the outside of the p-cooler, and excellent cooling ability is exhibited day and night. That is, when the heat radiator 22 is cooled in this way, the object to be cooled that is in contact with the heat radiator 22 is also cooled. FIG. 8 shows the radiation cooler of this embodiment. Actual measurement data of cooling capacity is shown. This actual measurement data is based on the heat radiator 22.
Changes in temperature over time are measured separately during the night and during the day.

Curve a shows the cooling capacity at night, and it is confirmed that when the outside temperature is 25°C, the temperature of the heat radiator 22 can be cooled down to 7°C in about 30 minutes. Curve gb shows the cooling capacity during the day, and it is confirmed that the temperature of the heat radiator 22 can be cooled down to 15°C in about 30 minutes when the outside temperature is 26°C. .

As described above, it can be seen from the actual measurement data that the radiation cooler of the present invention exhibits excellent cooling ability regardless of day or night.

Therefore, the radiant cooler of the present invention has, for example, its radiation direction 22
Is water used as a cooled object in the direction of discipline? By providing an M path, cold water can be easily obtained, and sufficient cooling can be achieved by guiding the cold water to a fan coil unit or the like in the room. For this reason, the radiant cooler is ideal for cooling homes, plastic greenhouses, etc. The radiation cooler is not just limited to cooling, but provides deep cooling lj1≦ The application of power to a wide range of other fields is also an ability.

In this example, the selective radiation layer 22b of the heat radiator 22 was formed by coating the surface if++ of the mirror-finished aluminum plate with an Afflex film having a thickness of 25 μm. However, the thickness of the Afflex film was Not limited to. However, when the floating thickness of the Afflex film coated on the surface of the mirror-finished aluminum plate becomes 40 μm or more, the emissivity in the wavelength range of 8 to 13 μm increases, but the reflectance in other wavelength ranges decreases to 1 ．． However, the problem arises that there is no effective cooling. Furthermore, if the thickness of the Afflex film is less than 0 .mu.m, the repulsion rate in the wavelength range of 8 to 13 .mu.m will increase and the emissivity will drop significantly, resulting in poor cooling performance. Therefore, the thickness of the Afflex film coated on the surface of the mirror-finished aluminum plate is 10 to 40 μm.
In addition, in this embodiment, the selective radiation layer 221) of the heat radiator 22 is formed of an Afflex film, which is a glaze of bipartite vinylidene, or is not limited to this, but is made of CoCr, O, / K, 80. , 813N4/K
, sO, i ft-iJ K2So.

/ K, 804 etc. 8! Inorganic materials with a two-layer structure such as
Vinyl fluoride-vinylidene fluoride copolymer?
Polyoxypropylene/, polypropylene Zt (d,
Even when the selective emissive layer 22b is formed using a single-layer organic material such as a difluoride copolymer, the thermal radiator 22
It has been experimentally confirmed that the spectral reflectance of 200 nm exhibits characteristics close to those shown in FIG.

FIG. 9 shows another embodiment of the radiation cooler of the present invention, in which a conductive layer 22a is formed using a mirror-finished aluminum plate with a thickness of 1 mm, and the surface of the mirror-finished aluminum plate is KF Film (registered trademark) is a type of tetrafluorocarbon copolymer.
is used as a heat bath layer to form a selective radiation layer 22b. This K
If the F film is too thick or too thin, it will deteriorate the cooling ability of the cooler, so it is up to you whether to set the film to a thickness of about 5 to 20 μm. In this embodiment, the conductive layer 22a is formed to have a thickness of 9 μm.
Fighting φ, outer diameter 12B! - A plurality of channels 30 made of aluminum tubes are fixedly connected to the bath.

Therefore, by installing this radiation cooler outdoors and passing water through the flow path 30, cold water can be easily obtained by VC. This is because the heat of the water flowing through the flow path 30 is conducted to the selective radiation layer 22b via conduction 1 m 22 a, and this selective radiation I
Cd 22 b is released from #: J-J to the outside.

According to experiments, the radiation cooler shown in Fig. 9 was formed to have the same size as the embodiment shown in Fig. 4 described above, and was installed outdoors with a view within a range of ±70° to the sky direction. When installed and operated, the radiation area was 1m2 under the condition of an outside temperature of 25℃.
17.31 hours of cold water at 10° C. was obtained for each 91 hours.

In addition, as in this embodiment, by fixing several lengths of the flow passages 30 made of aluminum tubes to the back surface of the fourth layer 22a, the strong IW and weather resistance of the heat radiator 22 can be improved. This can improve the durability of the entire cooler.

That’s all! As explained above, according to the present invention, the thermal radiator exhibits high reflectance in the wavelength range of 8 μm or less and 13 μm or more, and exhibits high emissivity in the wavelength range of 8 to 13 μm. It is possible to provide a radiation cooler that sufficiently performs radiation cooling based on the above and exhibits excellent cooling ability day and night.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the theory of A -K-)(ead, Figure 2 is
3 is an explanatory diagram of a conventional radiation cooler; FIG. 4 is an explanatory diagram of a preferred embodiment of the radiation cooler of the present invention; Figure 5 is an explanatory diagram of the heat radiator of the radiation cooler in Figure 4;
The figure is a characteristic diagram of the spectral reflectance of the heat radiator shown in Figure 5,
- Figure 7 is an explanatory diagram of heat transfer in a radiation cooler, Figure 8 is a characteristic diagram showing cooling capacity measurement data of the radiation cooler shown in Figure 4, and Figure 9 is an illustration of another embodiment of the present invention. This is an explanatory diagram of 3゜20・
...insulating container, 22...thermal radiator, 22a.
...Conduction layer, 22b...Selective emission layer, 30.
...Object to be cooled. C! υ 1342'- Figure 1 Figure 2 bale! (um) Y = 343- ㅅ嘗 Proceedings Amendment Layer (volume) March 1, 1981 Nikju'I'S:... Commissioner of the Japan Patent Office Shima 1) Haru @ Mr.
i-'' ・1. Indication of the incident 1980 Patent Application No. 180169 2. Name of the invention Radiation Cooler 3. Relationship with the Tadashi Ozuruishi Incident Patent Applicant Address Oazacho, Nagakute-cho, Aichi-gun, Aichi Prefecture Soji Yokomichi 41
First name of address (360) Yutaka Co., Ltd. 1)
Central Research Institute 5, Claims column and Detailed Description of the Invention column 6 of the specification to be amended, Contents of the amendment (1) The claims are corrected as shown in the attached sheet. (2) "Reflecting surface (hereinafter referred to as selected emitting surface)" in line 18 of page 5 of the specification is corrected to "emitting surface (hereinafter referred to as selected emitting surface)" 1゜(3) Specification No. 1 reflective surface 1 from 1st line to 2nd line on page 6
4" is corrected to "radiating surface 14." (4) "Reflecting surface 14" on page 6, line 7 of the specification is corrected to "emitting surface 14." (5) "Reflecting surface 14" on page 6, line 9 of the specification is corrected to "emitting surface 14." (6) "1 reflective surface 14" on page 7, line 13 of the specification
Corrected to "radiating surface 14". (7) "Tetrafluoroethylene copolymer, etc." on page 9, lines 8 to 9 of the specification is corrected to "ethylene tetrafluoroethylene copolymer, etc." (8) In the first line of page 11 of the specification, "tetrafluoroethylene copolymer, etc." is corrected to "ethylene tetrafluoroethylene copolymer, etc." (9) Specification 1, page 11, line 20 to page 12, line 1, “
"vinylidene difluoride" is corrected to "ethylene tetrafluoride ethylene copolymer". 01 "Vinylidene difluoride" on page 17, line 19 of the specification is corrected to "ethylene tetrafluoride ethylene copolymer." αυ In the specification, page 18, lines 4 to 5, "diboil copolymers, etc." is corrected to "vinylidene diboilide, etc." tnl On page 18, line 12 of the specification, "tetraboil copolymer" is corrected to "vinylidene diboilide." Claims (1) A heat insulating container into which an object to be cooled is introduced and which insulates the object from the outside except for a part, and a heat radiator that covers an exposed part of the insulating container, The radiator consists of a conductive layer made of a metal with high reflectance and thermal conductivity that is in conductive contact with the object to be cooled, and a conductive layer that is coated with the conductive layer and has a high emissivity (absorption rate) in a wavelength range where the light energy contained in external light is small. ) and has high transmittance in other wavelength ranges:
! r207/K, So. S's L4/Kt S"4 'It fchaKt S
Consists of a two-layer structure inorganic material such as Ox / Kt So+ or a single-layer structure organic material such as vinyl fluoride-vinylidene 70ride copolymer, polyoxyzolopylene-vinylidene difluoride, polypropylene or ethylene tetrafluoride copolymer. It is formed of a selective radiation layer, which absorbs the optical energy of external light and radiates heat from the object to be cooled in the specific wavelength range, and reflects external light in the wavelength range other than the specific wavelength range to make the object to be cooled. A radiation cooler that cools the body.

Claims (1)

[Claims] (1) A heat-insulating container into which an object to be cooled is introduced and insulating the object from the outside except for a part, and a heat radiator that covers an exposed part of the heat-insulating container, and the heat radiator is a A conductive layer that is in conductive contact with the body and is made of a metal with high reflectance and thermal conductivity; C0Cr, which has high transmittance in other wavelength ranges,
L), / to 2So,. 8i, fJ, /ni28044tahani, EIO3/
Inorganic materials with a two-layer structure such as So, vinyl fluoride vinylidene fluoride cobolima, and polyoxypropylene. a selective radiation layer made of a single-layer organic material such as vinylidene difluoride, polypropylene, or tetrafluoride copolymer; A radiation cooler characterized in that it cools an object to be cooled by reflecting external light in a wavelength range other than a specific wavelength range.