JPS6062515A - Radiation cooling wall and roofing material - Google Patents

Abstract

PURPOSE:To provide a superior cooling capability throughout day and night by a method wherein a wall member having cooled member provided therein and the cooled member thermally insulated from outside except a part thereof and a heat radiator body having a sufficient selectivity against the radiated light by covering the exposed portion in the wall. CONSTITUTION:A wall member 20 into which cooled material such as water is provided and thermally insulated from outside except a part thereof and a heat radiator 22 covering the exposed portion of the wall member 20 are arranged. The heat radiator 22 is composed of a conductive layer 22a in conductive touching with the cooled material and made of metal having a high rate of reflaction and high conductivity (for example, a mirror aluminum surface Al plate) and a selective reflection layer 22b covered onto the conductive layer 22a, having a high rate of reflection in a range of wave length with a low optical energy contained in an external light and a high rate of permeation in other wave length regions, such as non-organic material of double layer structure of CoCr2O4/ K2SO4 or organic material of single layer structure such as polyoxipropylene, a heat radiation from the cooled material as well as absorption of external light energy are performed in a range of specified wave length and then the external light is reflected in other ranges of wave length.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to radiation cooling walls and roofing materials, and particularly to a radiation cooling structure that cools walls and roofs using heat radiation.

Traditionally, air conditioning in buildings has been done by using the condensation and expansion of steam, and by using Rankine cycle coolers.
It is widely used.

However, such a Rankine cycle type cooling device requires energy every time it is operated, and a large amount of loss occurs when converting this energy. This one piece,
The drawback is that energy usage efficiency is poor and cooling costs are high. Especially in cooling devices that use electrical energy, cooling costs tend to increase year by year as energy costs rise.

Mafko, such Rankine cycle type cooling %M is,
Since there are many energy conversion steps, the entire device becomes complicated and large, which has the disadvantage of increasing equipment costs.

Therefore, it is desired to develop a cooling device that uses a cheap energy source, has a simple and inexpensive structure, and has an excellent cooling capacity.

A theory that makes it possible to provide such a cooling device was proposed by A. K. of Australia. This theory consists of three modes of heat transfer:
In other words, radiation cooling is performed by focusing on the movement of heat by radiation among radiation, convection, and conduction. The present inventor utilized this theory to invent a structure that performs cooling from the walls and roof.

FIG. 1 shows a cooling device based on this theory.

This cooling device includes a box-shaped heat insulating container 10 into which an object to be cooled is introduced and which insulates the object from the outside except for a part, and a box-shaped heat insulating container 10 that is installed inside the insulating container 10 facing an opening and radiates heat. A cover 16 that transmits radiation light is provided at the opening of the heat insulating container 1O formed from the body 12, and a body to be cooled (not shown) is in conductive contact with the heat radiator 12.

This cooling device has a heat radiator 12 inside the cooling device.
The heat radiator I2 is radiatively cooled by the exchange of radiation light between the heat radiator 12 and the outside of the cooling device through the cover 16, and is conductively connected to the heat radiator 12 to cool the object to be cooled.

By the way, the radiation surface 1 of the heat radiator 12 from the outside of the cooling device
The external light incident on the cooling device 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 cooling device to the outside includes radiation depending on the temperature of the radiation surface 14. There is a thermal radiation 300. Therefore, when the object to be cooled is cooled by radiation cooling as described above, the amount of heat inputted into the inside of the cooling device by solar radiation 100 and thermal radiation 200 is exceeded by the amount of heat radiation 3oO from the radiation surface 14 outside the cooling device. It is necessary to increase the amount of heat released.

FIG. 2 shows each radiation beam 100.2 transmitted and received on the radiation surface 14.
00.300 emission spectrum is shown. Here, the optical energy of the thermal radiation 3oo emitted from the radiation surface 14 to the outside of the cooling device varies depending on the temperature of the radiation surface 14, but the wavelength always remains close to about 10 μm when the temperature changes within the room temperature range where the cooling device is used. You can see more of Beak.

The optical power of the thermal radiation 200 incident on the radiation surface (4) from the atmosphere is greatly reduced in a specific wavelength range of 8 to 13 μITI around the wavelength of 10 μ. Therefore, the amount of heat of the thermal radiation 300 emitted from the radiation surface 14 to the outside of the cooling device is the same as that of the thermal radiation 200 that enters the radiation surface 14 from the outside of the cooling device.
The amount of heat is larger than that of 0.

Therefore, if the cooling device shown in FIG. 1 is used at night when there is no solar radiation 100, the amount of heat released from the radiation surface 14 to the outside of the cooling device will be larger than the amount of heat incident on the radiation surface 14 from outside the cooling device. At the same time, the heat radiator I2 is radiatively cooled, and the object to be cooled that is in conductive contact with the heat radiator 12 is also cooled.

The theory of A-L If e +l +J takes this idea one step further and selectively reflects and absorbs the radiated light 100.200.300 transmitted and received by the reflective surface 14, thereby changing the time between day and night. Equipped with excellent cooling capacity without straining.
This is an attempt to obtain a radiation cooling device. In other words, on the radiation surface used in the cooling device as shown in Figure 1,
A reflective surface that has high emissivity and absorption rate in a specific wavelength range of 3 μm and a good reaction rate in a wavelength range other than this specific wavelength range, that is, a wavelength range of 8 μn1 or less and 13 μm or more (hereinafter referred to as a selective emission surface). ).

If a selective radiation surface is used as the radiation surface 14 of the cooling device in this way, all of the solar radiation 100 from the sun will be reflected by the radiation surface 14, and the conditions will be the same during the day as when there is no solar radiation 100 from the sun at night. Therefore, the cooling device will be sufficiently cooled regardless of day or night.

Furthermore, as is clear from the radiation spectrum shown in Figure 2,
If only solar radiation 100 is reflected, it is sufficient to limit the selectivity of the radiation surface 14 to the wavelength range below (i-4μ■.However, A, K・11 (i) The reason why the surface 14 is required to have a high reflectance in a wavelength range other than 8 to 1311I+1 is to increase the cooling capacity of the cooling device.

Thermal radiation 2 incident on the radiation surface 14 from the atmosphere
Comparing the amount of heat 00 and the amount of heat 300 emitted from the radiation surface 14 to the outside of the cooling device, the amount of heat radiation 300 emitted from the radiation surface 14 is superior in terms of the total amount, but the Wavelength range and I 3 /ll11
In these seven wavelength ranges, thermal radiation from the atmosphere is partially superior. Therefore, by limiting the spectrum of the radiated light 200.300 transmitted and received in the radiation direction 14 to 8 to 13 μm, the difference in the total amount of heat entering and exiting the radiation direction 14 can be increased to increase the cooling capacity.

Then, based on the theory of this A・1(・He a d 1
As this radiation cooling device, A-W-Harri
s o o or G.

A radiant cooler is known, provided by 1' r (l I S (H).

FIG. 3 shows one radiant cooling device proposed by A-W.I.+irr.iso++ et al. This radiation cooling device includes a white colored paint 1 containing 35% TiO2 on the metal surface of an aluminum plate 14+1 with a thickness of 6 mm, which also has selective radioactivity in the radiation direction 14 of the heat radiator 12. The radiation surface 14 is formed by covering the coating film 14b.

However, in such a radiation surface 14, the above-mentioned A, K・1(e
Selectivity in a specific wavelength range as shown in the AD theory could hardly be expected, and the cooling capacity of the radiation cooling device was extremely low.

In addition, the radiation cooling device proposed by G-Troise et al.
The radiation surface 14 of the heat radiator 12 is formed by coating a thin film of LA (registered trademark). but,
The radiation surface 14 of this cooling device exhibits a certain degree of selectivity for a specific wavelength range, but it exhibits sufficient selectivity compared to the t-coselectivity explained by the theory of A, K, [1e and d. It's not a thing. Therefore, the cooling device proposed by G.i.
There is a drawback that the cooling capacity during the day when 00 is incident is significantly reduced.

Therefore, it is desired to develop a cooling device having excellent cooling capacity based on the theory of A-Head.

The present invention was developed in view of these 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. Our goal is to provide radiant cooling walls and roofing materials with a cooling structure that allows for cooling.

To achieve this objective, the radiant cooling wall of the present invention.

The roofing material has a structure in which the object to be cooled is introduced and insulates the object from the outside except for a part. including the body,
The thermal radiator includes a conductive layer made of a metal having high reflectance and thermal conductivity, which is in conductive contact with the object to be cooled, and is coated with the conductive layer and has a conductive layer that is in conductive contact with the object to be cooled, and is coated with the conductive layer and has a conductive layer that is in conductive contact with the object to be cooled. 2804,5 to CoCr2O7/, which has emissivity (absorption rate) and high transmittance in other wavelength ranges.
iBN4/2S□, 4tj, =K 2803/K
2 S (, ) 4 is formed from an inorganic material with a two-layer structure, and a selective emissive layer is formed from an organic material with a single-layer structure such as vinyl fluoride, vinylene fluoride, and cobolikobolima. In the specific wavelength range, the optical energy of external light is absorbed and heat is radiated from the object to be cooled, and in a wavelength range other than the specific wavelength range, external light is reflected to cool the object to be cooled. .

Next, preferred embodiments of the present invention will be described based on the drawings.

FIG. 4 shows a preferred embodiment of the invention. The radiation cooling wall of the present invention includes a wall frame 20 that has a structure in which a body to be cooled (not shown) is introduced and insulates the body from the outside except for a part, and a body to be cooled inside the heat insulating wall frame 20. and a heat radiator 22 that is in conductive contact and covers the exposed portion of the heat insulating wall frame 20. In the embodiment, the heat insulating wall frame 20 is formed in a box shape with an opening on one side, and the heat radiator 22 is formed in a plate shape and is provided inside the heat insulating wall frame 20 to cover the opening of the heat insulating wall body 20. ing.

A characteristic feature of the present invention is that the thermal radiator 22 has selectivity in a specific wavelength range, which is explained by the theory of CAD, that is, low light energy contained in external light 100.200. High emissivity in a specific wavelength range of 8 to 13 μ...
8 μI of high optical energy contained in external light 100.200
The objective is to provide good selectivity in reflectance in the wavelength range below TI and above 13 μm. Therefore, as shown in FIG.
Inorganic materials with a two-layer structure such as 2O7/2804°S summer 3N4/2SO4 and 2SO8/2SO4, vinyl fluoride, vinylidenofluorite cobolima, polyoxypropylene.

Selective radiation 11 made of material and coated on said conductive 1m'22a! ! The heat radiator 22 is formed from 22 b and f
It is characterized by: This is due to the following reasons.

That is, the reflectance of the metal forming the conductive layer 22a is controlled for light in all wavelength ranges, and the selective emission layer 22a has a low reflectance.
The inorganic material with a two-layer structure and the organic material with a single-layer structure forming 211 have a high emissivity for light in the wavelength range of 8-13μI11 and a low transmittance for light in the other wavelength range. . Therefore, this heat radiator 22 has 8 to 13
Since light in a specific wavelength range of μIl+ is absorbed by the selective emission layer 22b, and light in other wavelength ranges is totally reflected by the metal surface of the thermally conductive layer 22a, the emissivity is high in the specific wavelength range of 8 to 13 μrrl. , and other wavelength ranges, i.e. 8μ
It exhibits high reflectance for light in the wavelength range of 13 μm or less and 13 μm or more.

Note that in this embodiment, the thickness of the thermally conductive layer 22a is 0.
．． 8 fights, 1m long and 9.5m wide mirror aluminum 25μ
It is formed using M Afflex Film (M registered trademark). This Afflex film is coated onto the aluminum plate using electrostatic force.

FIG. 6 shows the spectral reflectance characteristics of the thermal radiator 22 of this embodiment, which is formed using an aluminum plate and an AFLEX film.
It is understood that the selectivity in the specific wavelength range explained in the theory of d is excellent.

In addition, in the radiation cooling wall of this embodiment, in order to obtain a sufficient heat insulation effect by the heat insulating wall frame 20, the heat insulating wall frame 20 has a thickness of 3°.
It is made of foamed urethane with a thickness of 0.1 mm, and an aluminum foil 24 with a thickness of 0.1 mm is attached to the inner surface of the wall frame 2o to prevent the transfer of radiant heat from the wall frame 2o to the heat radiator 22. The inside of the heat radiator 22 and aluminum foil 24 is filled with water to utilize the cooling effect.

Also, the opening of the cooler is covered with a cover holder 26, which shields the outside air and improves the cooling effect.
8 is installed. This cover 28 is made of a polyethylene film having a thickness of 201111 mm so that it is transparent to light in all wavelength ranges.

The present invention has the above configuration, and its operation will be explained next.

When the radiation cooling wall of the present invention is actually used, as shown in FIG. Heat transfer due to heat conduction and air convection is considered.

However, in the embodiment, the insulating wall frame 20 has excellent heat insulating properties and has an aluminum foil 24 attached to its inner surface to prevent the transfer of radiant heat from the heat radiator 22. The heat conduction through 2o becomes almost negligible. Furthermore, since the inside of the cooling wall is shielded from the outside air by the cover 28, when the surface temperature of the heat radiator 22 is lower than the outside air temperature, the movement of heat due to air convection becomes negligible.

Therefore, when the radiation cooling wall of the present invention is used as a wall material, the heat radiator 22 has the above-mentioned f, :A, K.
) 1 e a d theory, synchrotron radiation is transmitted and received, and excellent cooling ability is exhibited day and night.

That is, in the radiation cooling wall of the present invention, the thermal radiator 22 exhibits spectral reflectance characteristics as shown in FIG.
It has a high emissivity in the wavelength range of 8 to 13 μn).

After this time, the solar radiation 100 from the sun entering from the outside of the cooling wall through the cover 28 toward the heat radiator 22 is:
Since its wavelength is 4 lt m or less, most of it is reflected by the heat radiator 22.

Therefore, heat transfer into the cooling wall due to solar radiation 100 from the sun 1 is ignored.

Also, most of the heat radiation 200 from the atmosphere that enters the heat radiator 22 from the outside of the cooling wall through the cover 28 is reflected by the heat radiator 22, and the light energy is small. Only thermal radiation in the wavelength range l 3 It +n is absorbed by the thermal radiator 22 .

First, there is heat radiation 800 from the heat radiator 22 of the cooling wall, which corresponds to the surface temperature of the heat radiator 22, and is emitted to the outside of the cooling wall via the cover 28. Here, the heat radiator 22 has an emissivity in the range of 8 to 13μ1, and the heat radiation 300 from the heat radiator 22 has a large optical energy.
It is carried out in the wavelength range of ~13μ01.

Therefore, the transfer of heat due to the radiation light transmitted and received by the heat envelope 22 is caused by 8 to 1377 Il+, which has a small light energy.
It is sufficient to consider heat transfer due to thermal radiation 200 from the atmosphere in the wavelength range of 200 and thermal radiation 300 from the thermal radiator 22 in the wavelength range of 8 to 13 μITI, which has large optical energy. As is clear from FIG. 2, the heat transfer due to each of these thermal radiations 200 and 300 in the wavelength range of 8 to 13 μI11 is overwhelmingly due to the thermal radiation 300 from the thermal radiator 22.

Therefore, in the radiation cooling wall of the present invention, the amount of heat that goes out from the outside of the cooling wall is greater than the amount of heat that comes in from outside the cooling wall, and an excellent cooling capacity is exhibited regardless of day or night. That is, when the heat radiator 22 is cooled in this way, the object to be cooled that is in conductive contact with the heat radiator 22 is also cooled.

FIG. 8 shows measured data of the cooling capacity of the radiation cooling wall of this example. In this actual measurement data, changes over time in the temperature of the heat radiator 22 are measured separately during the night and during the day. Curve a shows the cooling capacity at night, and it increases the temperature of the heat radiator 22 by 7° in about 3 hours when the outside temperature is 25°C.
It is confirmed that the temperature can be cooled down to C. The curve 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 2 hours when the outside temperature is 30°C.

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

Therefore, the radiation cooling wall of the present invention may store water directly as a body to be cooled on the back surface of the radiation surface 22 as in the first embodiment, or may store water as a body to be cooled on the back surface of the radiation surface 22. If a flow path is provided, cold water can be easily circulated, and sufficient cooling can be achieved by guiding the cold water to a fan coil unit or the like in the room. This 1-piece, residential-use 1-piece is ideal for cooling houses, etc. First, the radiation cooling wall of the present invention is not limited to just cooling, but can also be applied to other wide fields due to its excellent cooling ability.

In this example, the selective radiation of the heat radiator 22 is formed by coating the surface of the mirror-finished aluminum plate with a 25 μm thick Afflex film.
However, the thickness of the Afrenox film is not limited to this. However, when the thickness of the Afflex film coated on the surface of the mirror-finished aluminum plate becomes 40/1111 or more,
Although the emissivity in the wavelength range of 8 to 13 μm increases, the reflectance in other wavelength ranges decreases, causing the problem that effective cooling cannot be achieved. Well, if the thickness of the Afflex film is less than lOμI11, it will be 8 to 13.
As the reflectance in the wavelength range increases and the emissivity decreases by a large amount, the cooling ability deteriorates. Therefore, the appropriate thickness of the affix film covering the surface of the mirror-finished aluminum plate is 10 to 40 .mu.m.

In this embodiment, the selective radiation layer 221 of the heat radiator 22 is formed of an Aflex film, which is a persimmon of dimorphic vinylite, and is not limited to this, but is made of CoCr2.
Two-layer inorganic materials such as O7/2804.5iBN4/K2SO4 or 280,1/2S04, vinyl fluoride-vinyritene fluoride copolymer, polyoxypropylene, polypropylene maf co are diboiling Even in the case where the selective emissive layer 22b is formed using a single-layer organic material such as chloride, the thermal radiator 22
It has been confirmed through experiments that the spectral reflectance of 200 nm exhibits characteristics close to those shown in FIG.

The conductive layer 22 is formed using a aluminum plate, and a type of vinylidene monofluoride is applied to the surface of the mirror aluminum plate, since if it is too thick or too thin, it will deteriorate the cooling ability of the cooler.
It is appropriate to set the thickness to about 20μIII. In the example, it is formed to have a thickness of 9 μm.

In this embodiment, a plurality of channels 30 made of aluminum tubes with an inner diameter of 10 mmφ and an outer diameter of 12 mmφ are fixed by welding as objects to be cooled to the back surface of the fcoconductor 1122;L formed of an aluminum plate. are doing.

Therefore, this radiation cooling wall is used as an outdoor wall and the flow path 30
By passing water through the pipe, you can easily obtain 1 m of cold water. This means that the heat of the water flowing through the flow path 30 is transferred to the conductive layer 22+l.
This is because the radiation is transmitted to the selective radiation @ 22 b via .

According to experiments, the radiation cooling wall in Figure 9 is 600x900x
I made it with a size of 90mm, installed it facing south, and it worked.
child.

First, as in this embodiment, the durability of the entire leg wall is improved on the back surface of the conductive layer 22a. In this embodiment, it can be used not only as a wall material but also as a roof covering.

As explained above, 1 As described above, according to the present invention, the heat radiator is 8
High reflectance in the wavelength range of μI11 or less and 13μm or more, and high emissivity in the wavelength range of 8 to 13μI11. It is possible to provide radiation cooling walls and roofing materials that exhibit excellent cooling capacity.

[Brief explanation of the drawings] Figure 1 is an explanatory diagram of the theory of A, K.) l c a d.
Figure 3 is a characteristic diagram of the radiation spectrum of the synchrotron radiation transmitted and received. Figure 3 is an explanatory sectional view of a conventional radiation cooling device. Figure 4 is a perspective view of a preferred embodiment of the radiation cooling wall of the present invention. Figure 5 is an enlarged cross-sectional view of the heat radiator of the radiation cooling wall in Figure 4.
. Fig. 6 is a characteristic diagram of the spectral reflectance of the thermal radiator shown in Fig. 5. Fig. 7 is an explanatory diagram of the movement of heat in the wall when the radiation l<n>.
The figure is a characteristic diagram showing the cooling capacity measurement of the radiation cooling wall shown in Figure 81''i4. Figure 9 is a cross-sectional view of another embodiment of the present invention. 20...Insulating wall frame 22...Thermal radiator 22・l...
Conductive layer 221J...Selective radiation J-30...-Subject h) Divine body No. 1 Fig. 00 Fig. 2 Wavelength (l1m) Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 6 Wavelength (μnl) Fig. 7 □ Time No. 9 Figure

Claims (1)

[Claims] (1) The object to be cooled is introduced and has a structure that insulates the object from the outside except for a part, including wall material or roof material, and a heat radiator that covers the kiln exit part of the heat insulating container, The thermal radiator includes a conductive layer made of a metal with high reflectance and thermal conductivity, which is in conductive contact with the object to be cooled, and is coated with the conductive layer and has a high emissivity (
CoCr2O4/2SO4', S+gN4, which has high transmittance in other wavelengths and long ranges
/ni2SO4matkohani2SO3/1ri2SO4 etc.2
It is formed from a selective radiation layer made of an inorganic material with a layered structure or an organic material with a monocrystalline structure such as a hinyl fluoride-hinylidene fluoride copolymer or Poma, and absorbs the optical energy of external light and A radiation cooling wall or roof material characterized by radiating heat from an object to be cooled and cooling the object by reflecting external light in a wavelength range other than a specific wavelength range.