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GBlist: Greywater and heat recovery

John Salman wrote:
>Aside from reuse and conservation of water there is a significant
>heat-energy value to greywater than can be recovered by incorporating
>heat exchangers. Here is an address for one such product that gives you
>an indication of potential recovery.http://www.oikos.com/gfx/

John, I think that the GFX that you cite is probably a good product but it
works best when the incoming (cold) feed to the water heater runs
simultaneous with the greywater (as e.g. with a shower) ... because I think
the heat recovery is directly to the cold feed piping wrapped around the
waste pipe.  It makes more sense in changing rooms at sports centers.  The
GFX is not so effective at recovering heat from washing machines for

Therefore. I more or less agree depending upon the recovery device/method.

Collecting rainwater instead of greywater for process uses in apartment
I agree with Warren that, if there is a combined sewer system (the storm
(rain) water feeds into the municipal sewer system) then collecting
rainwater water instead of greywater for these non-potable purposes seems a
better approach.  (NOTE: being non-potable, the collection system can be
less sophisticated than the model explained in the current Environmental
Building News).
When I was in last in Europe I saw some interesting work in this vein in
Aarhus, Denmark that Finn Norholm of PlanEnergi had installed. They had
developed a really simple leaf diverting system that was installed in line
of the existing downspouts for example. They also used a series of smaller
storage tanks, partly it was less expensive, partly they could be brought
into basements without widening existing openings
The Danish B.U.R. no doubt has literature.

Bruce Coldham


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