Re: [Paddlewise] Fresh water

From: "cholst" <cholst_at_bitstream.net>


> > Trying to think who else would face this sort of problem and guess it would
> > have to be the military. Does anyone know if they have access to energy
> > efficient, portable, desalination.
> 
> I believe the company that makes the Pur products supplies the same 
> desalinators to the military as to the public. So, no, there doesn't seem to 
> be an easier solution. 

Based on Peter's original post, I asked myself "How hard could it be to make 
a reverse osmosis desalinator with a solar powered pump?"   Well, after 
a couple of days on the web, I realize that the solution isn't just connecting a 
RO membrane in a pump and connecting a power regulator and photovoltaic
cell array.  While the concept is simple, actually creating the beast, with a 
meaningful flow rate (say, 1 litre per hour - hence a few hours on the
deck of the kayak per person), coupled with the pressures required (high 
quality, low power pump that can run dry without damage and survive kayaking
conditions) and the need to make a good quality membrane ends up being 
non-trivial in a big way and not very cost effective.  Sigh...  Now I know why
the Pur units are so pricey and not electric.

The only pure solar desalinator designs I know of off-hand are distillation units and 
aren't designed to be moved around.  Sigh again.  

Perhaps we can be genetically mutated into salt tolerant critters...  Boy, am
I glad I paddle the Great Lakes region (i.e.  fresh water)!

Mike

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