Kalwall with Nanogel: "The Light Stuff"
by Lloyd Alter, Toronto on 06.22.07
It looks a bit like a Japanese shoji screen; shoji literally means "everything and nothing," a definition that could also apply to this translucent panel. Kalwall is a sandwich of fiberglass-reinforced polyester with a filling of filled with Nanogel, Cabot's brand of " a hydrophobic aerogel consisting of approximately 95% air, in nano-sized pores that inhibit heat transfer through the aerogel material." It has a terrific insulation value of R20 (better than most codes require for a solid wall) wall while allowing 20% of the light through.
Kalwall has been making translucent walls and skylight systems since 1955 but the nanogel system is more attractive because of its higher R value. Says Bruce Keller, Kalwall's marketing vice president: "Nanogel is a giant step in technology for us. It's the magic insulation material."
As we move towards net zero energy building, perhaps we will see more of this. ::Kalwall via ::Materialicious
Sounds great, but last time I tried to get a sample of Aerogel, it seemed to be about $50 for a cubic-inch-sized sample.
Googling around for prices on this Kalwall stuff, I found an (old) 2003 report that said:
"The least expensive Kalwall R-20 panels are standard 4-ft.-wide skylights, in lengths from 4 feet to 20 feet. Since the price is about $40 to $50 per square foot, a 4’x4’ skylight will cost about $800." http://tinyurl.com/2gbhdf
So at that price, that shoji screen in the article's picture could roughly cost about $6500 for materials. Pretty expensive considering aerogel is 98% air!
Yeah. But 1) it's a new product so they need to make money back off it and they don't have a huge manufacturing facility and 2) the process probably isn't that easy.