The Core Principle of Aerogel Thermal Insulation

The core reason why aerogel is an excellent thermal insulator is its unique pore structure. It is 95% to 99% air or other gases in volume, which are encapsulated in nanometer-sized pores that form a natural barrier to heat transfer.

Heat transfer relies on three main methods: conduction, convection and radiation. In the case of aerogels, the nanoscale pores greatly restrict the movement of air molecules, reducing the amount of heat transferred through air convection. At the same time, the extremely long paths and small cross-sectional area of the slender solid skeleton dramatically reduce the efficiency of heat transfer through the solid.

Differential Advantages over Traditional Insulation

Compared to traditional insulation materials, aerogel achieves equal or even superior insulation without having to rely on a thick structure. This lightness and thinness gives it an irreplaceable advantage in scenarios where weight and space are important.

The core reason for aerogel's ability to be an excellent thermal insulator is its unique pore structure. It is 95 to 99 percent air or other gases in volume, which are encapsulated in nanoscale pores that form a natural barrier to heat transfer.

Heat transfer relies on three main methods: conduction, convection and radiation. In the case of aerogels, the nanoscale pores greatly restrict the movement of air molecules, reducing the amount of heat transferred through air convection. At the same time, the extremely long paths and small cross-sectional areas of the slender solid skeleton also dramatically reduce the efficiency of heat conduction through the solid.

Compared to traditional insulation materials, aerogel achieves equal or even better insulation without having to rely on a thick structure. This lightness and thinness gives it an irreplaceable advantage in weight- and space-critical scenarios.

Chemical and Physical Properties of Aerogels

Core Physical Properties

In terms of physical properties, the most notable feature of aerogels is their extremely low density, which ranges from 0.0011 to 0.5 g/cm3 . The lowest density solid materials produced by mankind today are all aerogels, including a silica aerogel that weighs only three times as much as air, and can be even lighter than air when the air in the pores is removed.

The density of aerogels in conventional applications is usually above 0.020 g/cm3, about 15 times that of air. Even so, an aerogel the size of 150 bricks weighs only as much as a gallon of water. A replica of Michelangelo's David statue using aerogel of this density would weigh only about 2 kilograms.

Key Chemical Properties

At the chemical level, aerogels are essentially the dried solid skeleton of a gel, which comes from removing the liquid component of the gel and retaining the intact porous structure, making them open porous materials. Its pores are mostly between 1 and 100 nanometers in diameter, and most do not exceed 20 nanometers, and this microstructure is the root of its special properties.

It should be noted that aerogel is a dry material, completely different from gelatin desserts, which are wet ordinary gels, and the word “gas” in its name originates from the gas or vacuum that fills the pores, rather than liquid.

In terms of physical properties, the most notable feature of aerogels is their extremely low density, ranging from 0.0011 to 0.5 g/cm3. The lowest density solid materials made by mankind are all aerogels, including a silica aerogel that weighs only three times as much as air, and can be even lighter than air after the air in the pores is removed.

The density of aerogels in conventional applications is usually above 0.020 g/cm3, about 15 times that of air. Even so, an aerogel the size of 150 bricks weighs only as much as a gallon of water. If this density of aerogel replica of Michelangelo's “David” statue, the weight is only about 2 kilograms.

At the chemical level, aerogel is essentially a dry solid skeleton of the gel, which is an open porous material by removing the liquid component of the gel and retaining the intact porous structure. Its pore diameter is mostly between 1 and 100 nanometers, and most of them do not exceed 20 nanometers, and this microstructure is the root of its special performance.

It should be noted that aerogel is a dry material, completely different from gelatin desserts, which are wet ordinary gels, and the word “gas” in its name comes from the gas or vacuum that fills the pores, not the liquid.

Types of Aerogels

Silicon Dioxide Aerogels

Aerogels are categorized according to their chemical composition, and different compositions of aerogels have their own performance focuses and are suitable for different application scenarios. Silicon dioxide aerogel is currently the most common and well researched type, and is also a typical representative of the low density aerogels mentioned above.

It has excellent thermal and acoustic insulation properties, strong chemical stability and relatively controllable cost, and is widely used in industry, construction and other conventional thermal insulation fields.

Carbon Aerogel

In addition to silica, carbon aerogel is also an important category, with outstanding electrical conductivity, while retaining the porous properties of aerogel, commonly used as supercapacitor electrode materials, which has a unique value in the field of energy storage.

Metal Oxide and Polymer Aerogels

In addition, there are metal oxide aerogels such as alumina aerogels and zirconia aerogels, which have excellent high-temperature resistance and can maintain structural stability in high-temperature environments, and are suitable for special scenarios such as aerospace and high-temperature equipment insulation. Polymer aerogels are more flexible, which can make up for the defects of brittleness of inorganic aerogels, expanding the application in the field of flexible materials.

The classification of aerogel is mainly based on its chemical composition, and aerogels with different compositions have their own focus on performance and are suitable for different application scenarios. Silicon dioxide aerogel is the most common and matured type at present, and is also a typical representative of the low-density aerogel mentioned before.

It has excellent thermal and acoustic insulation properties, strong chemical stability and relatively controllable cost, and is widely used in industry, construction and other conventional thermal insulation fields. In addition to silica, carbon aerogel is also an important category, its conductivity is outstanding, while retaining the porous properties of aerogel, commonly used as supercapacitor electrode materials.

In addition, there are alumina aerogel, zirconia aerogel and other metal oxide aerogel, this kind of aerogel has excellent high-temperature resistance, can maintain structural stability in high-temperature environments, and is suitable for aerospace, high-temperature equipment insulation and other special scenarios. Polymer aerogel is more flexible, can make up for the inorganic aerogel brittle defects, expanding the application in the field of flexible materials.

Advantages of Aerogel Insulation

Advantages of Thinness and Efficiency

The core advantage of aerogel insulation is its thinness and efficiency, which is much lower than the thickness and weight of traditional insulation materials such as rockwool and glasswool under the same insulation effect. This feature can effectively reduce the overall weight and improve the operational efficiency of equipment in load and space sensitive areas such as aerospace and transportation.

Advantage of stability and safety

It is chemically stable, not easy to age and deteriorate, and its service life is far more than that of traditional heat insulation materials, which can reduce the cost of maintenance and replacement in the later stage. At the same time, aerogel belongs to inorganic materials (most types), non-combustible, non-toxic, no need to worry about environmental protection and safety hazards during use.

Advantage of environmental adaptability

In addition, aerogel's waterproof and moistureproof performance is excellent, although the pore structure is open, it can effectively block liquid water infiltration, avoiding the degradation of heat insulation performance due to moisture, and it is suitable for humid and harsh working environment, which is the advantage of traditional heat insulation materials that is difficult to be compared.

The core advantage of aerogel insulation is that it is thin and lightweight with high efficiency. Under the same insulation effect, its thickness and weight are much lower than that of traditional insulation materials such as rock wool and glass wool. This feature in aerospace, transportation and other load- and space-sensitive areas, can effectively reduce the overall weight and improve the operational efficiency of the equipment.

It is chemically stable, not easy to age and deteriorate, and its service life far exceeds that of traditional thermal insulation materials, which reduces the cost of maintenance and replacement in the later stage. At the same time, aerogel belongs to inorganic materials (most types), non-combustible, non-toxic, no need to worry about environmental protection and safety hazards during use.

In addition, aerogel's waterproof and moistureproof performance is excellent, although the pore structure is open, it can effectively block liquid water infiltration, avoiding the loss of heat insulation performance due to moisture, and it is suitable for humid and harsh working environment, which is the advantage of traditional heat insulation materials that is difficult to compare.

Is aerogel really effective in practice?

The actual application effect in industrial scenarios

Aerogel is not only effective in practical application, but also shows irreplaceable value in many fields. In industrial pipeline insulation, the use of aerogel felt can significantly reduce the heat dissipation of the pipeline, reduce energy consumption, especially suitable for high temperature and high pressure pipelines, and because of its thin thickness, it does not affect the layout of the equipment around the pipeline.

Aerospace Scenario Verification

In the aerospace field, aerogel heat insulation is used in the cabin and engine parts of spacecraft, which can protect the internal equipment and personnel in the extreme temperature difference environment, and the lightweight characteristics will not increase the launch load of the spacecraft. After a long period of practice, aerogel has been proven to have stable and reliable heat insulation performance in harsh scenarios such as space exploration.

Application Effectiveness in Building Scene

In the field of construction, aerogel is used for exterior wall and roof insulation, which can improve the building thermal insulation effect without increasing the thickness of the wall, and reduce the energy consumption of air conditioning and heating. However, in practical application, attention should be paid to the construction process to avoid the destruction of the pore structure due to improper installation, which will affect the heat insulation effect.

Aerogel is not only effective in practical application, but also shows irreplaceable value in many fields. In industrial pipeline heat insulation, the use of aerogel heat insulation felt can greatly reduce the pipeline heat dissipation, reduce energy consumption, especially suitable for high temperature, high pressure pipeline, at the same time because of its thin thickness, does not affect the pipeline peripheral equipment layout.

In the field of aerospace, aerogel heat insulation is used in the cabin and engine parts of spacecraft, which can protect the internal equipment and personnel under the extreme temperature difference environment, and the lightweight characteristics will not increase the launch load of the spacecraft. After a long period of practice, aerogel has been proved to have stable and reliable thermal insulation performance in harsh scenarios such as space exploration.

In the construction field, aerogel is used for exterior wall and roof insulation, which can improve the building thermal insulation effect without increasing the thickness of the wall and reduce the energy consumption of air conditioning and heating. However, the actual application should pay attention to the construction process, to avoid the destruction of the pore structure due to improper installation, which will affect the heat insulation effect.

Application fields of aerogel

Aerospace field

Aerospace is one of the core application fields of aerogel, in addition to spacecraft thermal insulation, it is also used in the thermal insulation layer of astronauts' extravehicular space suits, which can provide temperature protection for astronauts under the extreme temperature difference environment in space. The key components of satellites and rockets are also often insulated with aerogel to ensure the normal operation of the equipment under complex working conditions.

Industrial field

In the industrial field, aerogel is widely used in petrochemical, electric power, metallurgy and other industries for pipeline, tank, boiler heat insulation. For example, when the petrochemical pipeline conveys high temperature medium, aerogel insulation can reduce heat loss, and at the same time reduce the surface temperature of the pipeline to improve production safety.

Construction and cold chain field

In the field of construction and energy saving, aerogel can be made into thermal insulation mortar, thermal insulation boards and other materials, which can be used for thermal insulation of new buildings and energy-saving renovation of existing buildings. In cold chain transportation, aerogel can improve the heat insulation performance of insulation box, prolonging the freshness and storage time of fresh food, medicine and other materials.

Potential Application Areas

In addition, aerogel has potential applications in environmental protection, electronics, medical and other fields. For example, in the treatment of water pollution, the use of its porous structure adsorption of heavy metal ions; in electronic equipment as a heat dissipation material for high-density integrated chip cooling, the future application scenarios will continue to expand with the technology upgrade.

Aerospace is one of the core application areas of aerogel, in addition to spacecraft thermal insulation, but also used for astronauts outside the cabin space suit insulation layer, can provide temperature protection for astronauts in space under the extreme temperature difference environment. The key components of satellites and rockets are also often insulated with aerogel to ensure the normal operation of the equipment under complex working conditions.

In the industrial field, aerogel is widely used in petrochemical, electric power, metallurgy and other industries in pipelines, tanks, boiler insulation. For example, when the petrochemical pipeline conveys high temperature media, aerogel insulation can reduce heat loss, while lowering the surface temperature of the pipeline to improve production safety.

In the field of construction and energy saving, aerogel can be made into thermal insulation mortar, thermal insulation board and other materials, which can be used for the thermal insulation of new buildings and the energy-saving renovation of existing buildings. In cold chain transportation, aerogel can enhance the thermal insulation performance of insulation box, prolonging the freshness and storage time of fresh food, medicine and other materials.

In addition, aerogel has potential applications in environmental protection, electronics, medical and other fields. For example, in the treatment of water pollution, the use of its porous structure to adsorb heavy metal ions; in electronic equipment as a heat dissipation material for high-density integrated chip cooling, the future application scenarios will continue to expand with the technology upgrade.

Conclusion

With its unique nanoporous structure, aerogel shows differentiated advantages in density, heat insulation, stability, etc. It not only breaks through the performance bottleneck of traditional materials, but also sees results on the ground in many fields such as aerospace, industry, and construction. From basic characteristics to practical applications, the core of its value lies in realizing efficient functions in a thinner and lighter form, taking into account the performance and scene suitability.

With the iteration of material preparation technology, the cost control and performance optimization of aerogel will continue to advance, and will not only expand more potential application scenarios in the future, but also may play a more critical role in energy saving, high-end manufacturing and other fields. For the pursuit of precise performance and space efficiency scenarios, aerogel is undoubtedly a high-quality material with both practicality and development potential.