Aerogels from Aspen Aerogels Inc. (Northborough, MA, U.S.; www.aerogel.com) feature an ultrathin profile and extremely low thermal conductivity, enabling appliance designers to insulate in tighter and smaller profiles. They also provide reduced condensation in critical areas of freezers, making it easier for appliances to achieve Energy Star ratings. Aerogels are now available from Pacor Inc. (Bordentown, NJ, U.S.; www.pacorinc.com) and its wholly owned subsidiary LIT Industries Inc. (Gastonia, NC, U.S.; www.litnc.com). Partnering with Aspen Aerogels Inc., they distribute and fabricate insulation materials made from nanoporous aerogels to meet customer specifications.

“Appliance makers, like most equipment manufacturers, are constantly striving to make their products more efficient and environmentally friendly,” says Joe Posda, product manager–Aerogels at Pacor Inc. “Aerogels are two to eight times more efficient than traditional insulation materials, so much less material is needed to achieve the same thermal results.” Besides their low thermal conductivity, “aerogels have the lowest embodied energy and lowest embodied CO2 of any insulation material. This, combined with energy efficiency, has allowed aerogels to obtain a silver level cradle-to-cradle certification.” Aerogels are also landfill disposable and contain no respirable fiber, he adds.

Posda says the aerogels’ composition is key to their ultrathin profile, light weight, and low thermal conductivity. “Aerogels consist of lightweight silica solids derived from a gel in which the liquid component has been replaced with gas. The silica solids, which are poor conductors, consist of very small, 3-D, intertwined clusters and comprise only 3% of the volume. Conduction through the solid is therefore very low,” Posda explains. “The remaining 97% of the volume is composed of air trapped in extremely small nanopores. The air has little room to move, so it inhibits both convection and gas phase conduction.” Because of the thermal stability, Posda says, there is no degradation of thermal values over time as compared with polyurethane foams.

Those qualities also give aerogels resistance to flame spread and smoke emission. “In hydrocarbon fires, for example, they protect piping and equipment longer. This is critical to increasing the reaction time needed to respond to a catastrophic event,” Posda tells APPLIANCE. “Aerogels are hydrophobic through the entire matrix of the material and not just on the surface, so they provide excellent resistance to moisture. Other insulations tend to absorb moisture over time, potentially corroding the substrate.”

While aerogels have been in existence for more than 70 years, Posda says, the technology to manufacture them commercially is relatively new. “Appliances and commercial cooking equipment have become a viable application over the last three to four years. As with any new product, manufacturers have to conduct extensive testing programs in-house,” Posda says. “Many appliance manufacturers have been testing aerogels over the last 12–18 months, with several commercial applications now in place.”

Aerogels can be cut, bonded, and attached in the same way as traditional insulation materials. But unlike traditional materials, their thin profile increases internal volume, providing more usable area for the same footprint. Aerogels also allows engineers to design smaller units that do the same job as existing products. “They can also engineer a more energy-efficient appliance with the same insulation thickness,” says Posda.

Currently, two aerogel products are available for appliance OEMs. Pyrogel XT is a high-temperature insulation blanket formed of silica aerogel and reinforced with a nonwoven, glass-fiber batting. With a maximum use temperature of 1200°F (650°C), it is available in thicknesses of 5 and 10 mm. Pyrogel XT has a density of 11 lb/cu ft (0.18 g/cm3) and is hydrophobic. It is suited for stove range tops, oven wall cavities, hot water heaters, and commercial cooking equipment.

Cryogel Z is a flexible aerogel insulation blanket engineered to deliver maximum thermal protection with minimal weight and thickness and zero water vapor permeability. Also available in thicknesses of 5 and 10 mm, Cryogel Z has a maximum use temperature of 194°F (90°C). It’s also hydrophobic, with a density of 8.0 lb/cu ft (0.13 g/cm3). Cryogel Z’s properties make it attractive for manufacturers seeking maximum thermal protection in cryogenic cold applications, such as refrigerators, and walk-in coolers.

With plants in New Jersey, North Carolina, and Georgia, Pacor and LIT Industries fabricate aerogels by die-cutting, laminating, CNC cutting, encapsulating, and close-tolerance slitting and sheeting. Application of pressure-sensitive adhesives can also be performed.