Ambiently Dried Aerogel for Thermal Insulation in High-Temperature Applications
Innovators at Michigan State University (MSU) have developed a novel porous silica-based aerogel material and the process for its fabrication. In contrast to the supercritically dried aerogel, a related material, the MSU approach uses gel and liquid extraction. Evaporation of the precursor solvent is performed at room temperature and pressure, producing the novel ambiently dried aerogel insulation. This ambient drying of the precursor solvent eliminates the need for expensive and complex super-critical drying and/or solvent exchange processes, making the material more accessible for commercial applications. The aerogel maintains its shape during drying without relying on "spring back" or surface treatments to maintain the original shape. The resulting solid material has numerous beneficial properties, most notably its effectiveness as a thermal insulator.
Description of Technology
The aerogel produced by this relatively simple process has excellent high temperature stability, and, with the proper additives, the final product has good thermal conductivity and excellent machinability. The near-zero shrinkage and absence of spring-back effect during the drying phase makes this material ideal for casting in place around rigid parts with complex geometries. Potential applications for this aerogel material and microporous insulation are numerous over diverse industries, particularly those requiring good insulating properties in a limited space.
The MSU ambiently dried aerogel offers a variety of benefits when compared to other types of insulation, including existing aerogels.
- High temperature insulator: Performs at temperatures from 127 C to 800 C
- Low thermal conductivity: Thermal insulation performance of 60 mW/mK can be achieved at room temperature; this can be reduced further (~10 mW/mK) with fiber enhancements of titanium dioxide (TiO2)
- Superior high temperature stability: Shrinkage of less than 3% at 700 C
- Simplified process: Eliminates expensive supercritical drying typically required to produce aerogels
- Lower cost: MSU process eliminates expensive supercritical drying required for current aerogel processing
- Castable and machinable: Can be cast in place on complex geometries and final product is easy to machine
- Improved sublimation barrier performance: Increased density over super-critically-dried aerogels may be a benefit in suppressing sublimation for some materials used in thermoelectric generators
This material has the potential to be used in a variety of industries including automotive, aerospace, oil and gas, and construction. A few example applications include:
- Thermoelectric generators: The MSU developed ambiently dried aerogel has been demonstrated successfully in a thermoelectric generator (TEG) used in a General Motors (GM) vehicle's waste heat recovery system, improving the vehicles efficiency and reducing carbon dioxide (CO2) emissions. In addition to these automotive applications, the aerogel could similarly be applied to thermoelectric coolers or other thermoelectric components.
- Industrial insulation: The outstanding thermal performance of aerogels is key to their increased demand in the oil and gas industry where critical insulation is required. The MSU aerogel could also be used to improve insulation performance in the building and construction industry.
- Heat shields: The properties of the MSU aerogel allows it to serve as an effective heat shield, particularly in applications with intricate parts such as used in the automotive and aerospace industries.
- Cryogenic tanks: The MSU aerogel is also suitable for cold temperature applications and could be used to manufacture containers for cryogenic fluids, such as those used to transport liquid natural gas (LNG).
- Engineered textiles: The MSU aerogel could be used to develop novel waterproof or insulated materials for use in the clothing and protective equipment industries.
Patent is pending
Jeff Sakamoto, Ryan Maloney, Travis Thompson
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Michigan State University