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[DPRG] Solar still

Subject: [DPRG] Solar still
From: RoboVac robovac at mninter.net
Date: Mon Dec 23 11:10:02 CST 2002

My senior project was designing a solar heated swimming pool to be used for
nine months a year in Minnesota.  It can be done but it is very expensive.
The interest payments on the equipment were lots more then the cost of the
natural gas needed by a gas heater.  And this was taking into account all
the tax credits and 50% federal matching payments.  Note that this was done
25 years ago so the economics have changed since then.

The key to cold weather operation was to insulate the solar collectors and
use two or three panes of glass/plastic to avoid heat loss.  The angle of
the panels should be set to optimize performance in the coldest month of
use.  Also cover half of a large backyard with solar collectors as well as
the whole roof.  The most efficient collectors are flat plates with the
water flowing over the entire surface area.

William Crolley



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