Aerogels, a bit of toilet-talk, and a visit to Real Goods
- To: domesteading at sculptors dot com
- Subject: Aerogels, a bit of toilet-talk, and a visit to Real Goods
- From: Patrick Salsbury <salsbury at sculptors dot com>
- Date: Mon, 08 Jun 1998 23:22:02 -0700
Lots of things have been going on with me, and I've been bouncing all over
the California area recently.
On Memorial Day Weekend, Stacie and I went north to Ukiah, CA, and visited
the Real Goods Solar Living Center ( http://www.realgoods.com/ ) which was
just incredible. They've built an oasis out of a former Caltrans gravel
pit/dump area, and are currently generating between 10-13Kw/hours of power
daily though wind and solar generation. They have a LOT of really great
things going on there. Too many to mention in a quick note. But check out
their site, and if you're anywhere near northern California, I'd recommend
checking it out. They're about 2-3 hours north of San Francisco.
One thing that struck me greatly was a neat design they had in the men's
room, of all places. They had waterless urinals there, which used very
intelligent design principles to get around standard (and wasteful)
practices. The urinal had an "oil-trap" in the bottom that caught fluid as
it went down the pipe. Since oil floats on water, all the urine goes down
the pipe, and the whole thing remains odor-free. Also, the non-flushing
urinal saves about 45,000 gallons of water per year. They've got a few of
them installed, and are saving about 150,000 gallons per year at the
center. Not bad...
One of the problems with composting human waste is that the ammonia and
other chemicals in urine are counter-productive to the composting action of
the microbes in solid waste. If you can separate the two BEFORE they go
into the composting repository, you'll achieve greater success. Designing a
toilet that can do this separation for females is difficult. I've discussed
it a bit with Harold Cohen, my design prof. from Buffalo. For males it's
quite easy, though, just by installing a urinal. I'd guestimate that about
5 out of 6 visits to the men's room are for liquid waste, rather than
solid. So eliminating the flushing of a "standard" 6 gallons toilet for
those visits would save 30 of 36 gallons, or 83% of the water. And even for
a low-flush toilet of only 1.4 gallons, you end up saving that 83%, but you
use only 1.4 instead of 8.4 gallons.
I'm beginning to consider putting a urinal (probably oil-trap/waterless)
as standard-issue in production models of the autonomous house. Thoughts?
Another thing they had there was the actual building of the Solar Living
Center. It's a straw-bale construct, and they left one section of the wall
open, so you could see how it was put together. I thought this was really
neat, as straw-bale is an interesting method of construction. One thing I
found very surprising was a comparison of the thermal capabilities of
straw-bale with another material I'm very interested in: Aerogels. Aerogels
are EXTREMELY lightweight materials that can be transparent, colored, or
totally opaque, and which have phenomenal insulating capabilities.
For those not familiar with building info, insulation is mesured by an "R
Factor", where one "R" is about the insulation you get from a single pane
of glass. The straw bale walls at Real Goods were about 27" thick, and had
an R factor of 67. Aerogels, by comparison, have an R factor of 20 PER
INCH, and if you draw out the air and make it a vacuum inside the aerogel,
it goes to R32 per INCH. That means that a 2" thick wall of evacuated
aerogel (mostly transparent, mind you, so it could serve as a light-passing
wall or a slightly blurry "window") would give you R64, or about the same
as that 27" of straw bale. (!!!)
There are some technical issues with aerogels. They're brittle. If you
smash one, it basically crushes to silicon dust like fine sand. They are
tricky to manufacture, but not impossible, by any means.
As you can probably tell, I'm quite fond of Aerogels. I've got links to
some detailed technical info on how they're made, chemically, and also have
found a couple of absolutely mind-blowing pictures that demonstrate their
insulating capabilities better than words can describe. I'll put them up on
a web page shortly, so you can see for yourself.
I'm thinking that aerogel panels will be another prime ingredient for
manufacture and building of these autonomous houses, and have fairly
detailed plans in mind for how to do it. Any chemists out there?
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