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Temperature induced emissivity reversibly variable material

A technology of emissivity and mass percentage, applied in the field of material science and engineering, can solve the problems of complex structure, high price, no materials, etc., and achieve the effect of reducing environmental pollution, saving fossil energy, huge economic and social benefits

Inactive Publication Date: 2004-11-10
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the complex structure of the device used and the high price, this method is greatly limited in its wide application in buildings.
[0004] Studies have shown that to create a thermally comfortable environment for buildings requires a state that can reflect a large amount of solar radiation and emit a large amount of its own heat in summer (that is, a low absorption-emission ratio state with low absorption rate and high emissivity), and it should be converted into a state that can absorb a large amount of heat in winter. Materials that radiate solar radiation and seldom emit their own heat (that is, a high absorption-emission ratio state with high absorption rate and low emissivity), unfortunately, there is no such material available worldwide at present, so it is proposed to material science researchers A serious challenge is to develop and research building materials that are in a state of low absorption-emission ratio in summer and high absorption-emission ratio in winter, and can spontaneously and reversibly switch at the thermal comfort temperature of the building (about 18°C), that is, air-conditioning building materials.

Method used

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  • Temperature induced emissivity reversibly variable material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] The material ratio of temperature-induced emissivity reversible change is:

[0039] La 2 o 3 15%

[0040] CaO 10%

[0041] mn 3 o 4 70%

[0042] Na 2 O, K 2 O 5%

[0043] The total amount meets 100%

[0044] Weigh each component material according to the above-mentioned ratio, and grind it with a grinder, and its fineness is not more than 5% based on the sieve balance of a 0.080mm square hole sieve. Then the ground powder was pressed into tablets and fired in air at 950°C for 14 hours. After taking it out for cooling, crushing, re-grinding, tableting, firing in air at 1200°C for 20 hours, and cooling to room temperature with the furnace, the material of the present invention is obtained. The emissivity of the temperature-induced emissivity reversible change material changes from 0.90-0.92 above 340K to 0.66-0.86 below 340K, the range of change is about 0.26, the transition temperature is about 340K, and the emissi...

Embodiment 2

[0046] The material ratio of temperature-induced emissivity reversible change is:

[0047] La 2 o 3 5%

[0048] SrCO 3 5%

[0049] mn 3 o 4 75%

[0050] Na 2 O, K 2 O 15%

[0051] The total amount meets 100%

[0052] Weigh each component material according to the above-mentioned proportioning, and use a grinder to grind, and the fineness is not more than 3% based on the sieve balance of a 0.080mm square hole sieve. Then the ground powder was pressed into tablets and fired in air at 850°C for 15 hours. After taking it out for cooling, crushing, re-grinding, tableting, firing in air at 1150°C for 20 hours, and cooling to room temperature with the furnace, the material of the present invention is obtained. The emissivity of the temperature-induced emissivity reversible change material changes from 0.85-0.86 above 320K to 0.58-0.59 below 320K, the range of change is about 0.27, the transition temper...

Embodiment 3

[0054] The material ratio of temperature-induced emissivity reversible change is:

[0055] La 2 o 3 25%

[0056] SrCO 3 10%

[0057] mn 3 o 4 50%

[0058] CaO 15%

[0059] The total amount meets 100%

[0060] Each component material is weighed according to the above-mentioned proportioning, and a grinder is used for grinding, and its fineness is not more than 2% based on the sieve balance of a 0.080mm square hole sieve. Then the ground powder was pressed into tablets and fired in air at 1100°C for 5 hours. After taking it out for cooling, crushing, re-grinding, tableting, firing in air at 1250°C for 10 hours, and cooling to room temperature with the furnace, the material of the present invention is obtained. The emissivity of the temperature-induced emissivity reversible change material changes from 0.80-0.82 above 296K to 0.46-0.64 below 296K, the range of change is about 0.36, the transitio...

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Abstract

The invention relates to a reversibly changing material with temperature emittance used for air-conditioning type construction materials, which is prepared from La2O3, SrCO3, Mn3O4, Na2O, K2O and CaO of a finite weigh proportion through burning, first in 850-1100 deg. C air for 5-15 hrs, and in 1150-1250 deg. C air for 10-20 hrs, the material exhibits low emittance property at low-temperature, thus diminishing thermal transpiration on the object surface, when temperature arises, it exhibits high emissivity property, thus increasing thermal transpiration on the object surface, the two different properties can vary reversibly with the temperature.

Description

technical field [0001] The invention belongs to the field of material science and engineering technology, and specifically relates to a temperature-induced emissivity reversible change material for air-conditioning building materials, which can be used for building exterior wall coatings, cement-based plastering materials, etc., and can also be used for vehicles, ships, large storage Tanks, large steel structures, daily necessities, military camouflage, aerospace thermal control coatings, etc. technical background [0002] Warm in winter and cool in summer, the house has been the dream pursued by human beings since ancient times, because it is an important aspect of human beings' basic survival needs of "food and clothing". However, the real world is often cold in winter and hot in summer. On the one hand, the incident angle of the sun on the ground changes greatly in winter and summer. On the other hand, the solar energy absorption rate and thermal emissivity of building ma...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/36C04B35/622C09D5/26
Inventor 马一平
Owner TONGJI UNIV
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