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Microporous Theory and Benefits
History:
The idea of microporous insulation was originally developed in the 1940’s, and was originally designed to be employed primarily in nuclear, space and aerospace applications because of its ability to outperform conventional insulation systems with less material and weight in a smaller amount of useable space. Although it was initially considered to be too expensive across the board for use in more price sensitive commercial, industrial and automotive applications, new formulations and manufacturing processes developed by ThermoDyne have produced additional forms of the same type of insulation and made it available to a large number of other applications outside of traditional aerospace markets.
Physics:
Microporous insulation significantly reduces the passage of heat energy through the insulation material by minimizing the three modes of heat transfer: convection, conduction and radiation.
Convection is minimized due to the microscopic voids that the ceramic particles and fibers form. These voids are smaller than path necessary for air molecules to travel effectively, and, as a result, do not allow air molecules to carry heat easily through the material.
Conduction is minimized in the microporous structure by limited particle-to-particle contact of the various components that comprise the microporous mix formulation. Although the particles are close enough together to form voids that minimize air convection, they are also far enough away from one another to minimize solid conduction of heat energy.
Radiation in minimized in the microporous insulation structure through the use of specially selected particles called opacifiers. These particles are specifically designed to reflect, refract and re-radiate radiation energy and prevent it from traveling easily or freely through the microporous material.
Benefits:
Space and Weight Savings:
Microporous insulation is ideal in environments where space and weight constraints are major concerns in the application. Although this is most readily apparent in the aerospace industry, where every extra ounce of added weight that can be eliminated improves profitability, fuel economy and overall performance, there are also many tangible benefits to saving space and/or weight in industrial and commercial applications.Some examples of industrial and commercial arenas currently already benefiting from the space and weight savings associated with the use of microporous insulation include:
increased capacity for ladles in glass and molten materials manufacturing, as well as greater allowed space for materials processing in bakes, kilns, ovens and feeders,
thinner composite wall linings in carbon bakes, ducts, pipes, incinerators, glass or metal manufacturing facilities,
lighter and more efficient commercial and passenger airliners and automobiles, as well as military fighters, bombers, smart munitions and guided projectiles.
Improved Efficiency:
Microporous insulation is advantageous in any application where high temperatures must be maintained for the overall success or operation of a process. In molten metal applications, the presence of microporous in the lining of a ladle may decrease the amount of metal “freezing” that occurs and any amount of re-heat time necessary, and may also help maintain an even distribution of temperature throughout the ladle to encourage homogeneity throughout the molten metal material.
Energy (Cost) Savings:
Perhaps one of the greatest and most visible additional benefits of microporous insulation is the direct amount of energy (and therefore direct energy cost) conserved through the use of a microporous system as opposed to a traditional system. Although microporous insulations tend to be more expensive that inexpensively manufactured glass or mineral wools, the cost can often easily be justified on the basis of dollars saved through energy conservation if not solely on the basis of space and/or weight savings. The following example below illustrates this point:
*Example: An operator of a fictional 100 SF industrial oven is looking to replace his current oven lining. The oven continuously operates at 1800°F and is currently lined with 1” of 8lb/ft3 ceramic fiber blanket. If the oven owner were to replace the ceramic fiber blanket with 1” of 16lb/ft3 DynaGuard microporous insulation, he would save $.02/kWh/ft2. This equals roughly $2.00/kWh for the entire oven.
Additionally, in order to achieve the same measure of thermal performance from the ceramic fiber blanket, he would need to replace his current 1” lining with nearly 3” (66% more) of the same material on each insulated surface.
*Example:
Simulation performed using the following figures, parameters and systems:
1 kWh = 3,413 BTU
1 kWh = $.065
Simulation run by using thermal calculations based on ASTM C-680
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