Benefits Of High Thermal Conductivity Insulators
Efficient Thermal Management in Electronics used to help control heat transfer. They are available in many different forms. Some are made of natural materials such as wood, cellulose and wool. Others are manufactured from plastics, polymer composites, fiberglass and ceramics. Some are also electrical insulators. All of them are used to reduce the transfer of thermal energy from hotter objects to cooler ones.
One of the most important properties of any insulation material is its Thermal Conductivity (also known as l or k). This is the measure of the ease with which a material transmits thermal energy through it. The higher the thermal conductivity, the more easily it transfers heat. The lower the thermal conductivity, the more effective the insulation.
The thermal conductivity of a material is a function of the type of atoms, molecules or ions that make up it’s molecular structure and the temperature of the environment in which they are moving. For example, metals tend to have high thermal conductivity as the electrons in their atomic structures can move freely, while non-metallic substances such as polymers and ceramics have much lower thermal conductivity as their atoms or molecules are more rigid and less mobile. The temperature of the insulated material also affects its thermal conductivity.
In general, a material’s thermal conductivity increases as its temperature rises and decreases as it cools. The physics behind this is that as the particles in a material vibrate more vigorously, they lose energy and therefore have less overall mass. The resulting loss in energy makes the electrons less likely to be attracted to one another and lessens their speed of movement.
Insulators are generally classified by their thermal conductivity as low, medium or high. The most common types of insulator include:
Air and other gases are very poor thermal conductors because they don’t have a large bulk flow driven by buoyancy or density differences like liquids and solids. This property is exploited in many insulating materials which trap air in small pockets, cells or voids. Examples of this are expanded and extruded polystyrene insulation, silica aerogel, wool insulation and even natural biological insulators such as fur and feathers.
Wood fibre insulation is a relatively new product which became commercially available about twenty years ago when engineers from the timber producing regions of Europe developed ways to convert waste from sawmills and thinnings into insulating boarding. The product is manufactured by grinding up and soaking in a solution of water and inorganic salts to provide the necessary strength. The resulting boards are both highly durable and thermally efficient.
The main disadvantage of this insulation is that it must be protected from naked flames and high temperatures until it has had a chance to fully sinter to a hard, stable state. The resulting dust arising from this process, which can be considerable, also poses a fire risk and must be taken appropriate precautions with. For this reason it is generally only suitable for interior use in areas where there is no exposure to flames or high temperatures.