Waste material becomes very efficient insulation

Your next refrigerator might be sheathed in renewable rice, if a team of students from the University of Michigan have anything to do with it. With just 12.5mm of rice husk ash they reckon they can achieve the equivalent of over 100mm of conventional petroleum-based insulation.

With claims that the 11 million fridges sold annually in the US could be made 50% more efficient, the judges of the Massachusetts Institute of Technology Clean Energy Prize obviously saw the potential in such technology. Such that they awarded the students first prize, which came with a cheque for $200,000. That will now no doubt help them as they launch a start-up company, Husk Insulation, to commercialise their product.

Husk Insulation will manufacture a special type of high-performance insulation called a vacuum insulated panel (VIP). VIPs take advantage of the insulating effects of a vacuum to produce significantly higher R-values (the standard for measuring thermal insulative effectiveness) than conventional insulation. VIPs are rigid panels comprised of a core material and a foil laminate membrane. The vacuum inside a VIP greatly reduces the conduction and convection of heat. While the R-values of conventional insulation are generally 4-8 per inch, VIPs have R-values between 30-50 per inch.

Although VIPs have been around for more than 20 years, they have not taken off in the mass market because they are generally not cost competitive with conventional insulation. Typical core materials (precipitated silica, superfine fibreglass, etc.) are simply too expensive even though products using VIPs need far less insulation material by volume.

Husk uses a proven & proprietary process to convert rice husk ash (RHA) into the core material for our vacuum panels. RHA is the by-product of agriculture and energy production and millions of tons of RHA are land filled annually. As a result, Husk expects to dramatically reduce the cost of VIPs, making them cost competitive in the mass market.

The founders of Husk Insulation figure it will take them about 18 months to bring the rice husk insulation to the fridge market. For which they calculate $425,000 USD will be required. Once they’ve captured the refrigeration industry, they have their sights set on the housing and transportation markets.

Original article: Warren McLaren. 14 May 2009. Treehugger. Read more…