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Re: GBlist: Drainwater heat recovery



Yes, I'm sure batch heated water will be quite hot in the afternoon in
Colorado, but I was thinking more of the morning. We may not be able to
give up the morning shower and with just solar and propane that means the
propane will be carrying most of the load. I thought the GFX would help me
out there.

Could you tell us all more about your experiences with solar water heating?
What kind of system did you have? Did you make it yourself? The more
details you can provide the better!

Going on Mike Reynold's advice in the Earthship books, I'm thinking that
active water heating systems are probably too complicated. He also says
that buying a commercial batch heater is not worth the money and recomends
that one go to a welder and get a welded steel box, no more than 4 inches
thick, otherwise sized to fit in your house's south face, and paint it with
black stove paint. He also has a diagram for building a box with tempered
glass (what the heck does that really mean anyway?) and rigid insulation
such that the steel box never touches any wood.

He says that making it thinner than 4 inches results in too hot water. (He
does all his experiments to the South of me in New Mexico, I think he
probably sees about the same amount of sun energy that I do in the Colorado
high country.)

In earthships there are two holes in the batch heater, one at the bottom
and an overflow at the top. There are valves such that you can send water
into the tank (until it starts spilling out the overflow into an indoor
planter and you know it's full). Then you wait for the sun to heat it.
There's another valve that changes your water supply from the cistern to
the batch heater and you go take your shower with gravity fed solar heated
water. His system has the advantage of being simple but I think I would
prefer it if there wasn't so much messing about with valves. What I
particularly don't like is the thought of the batch heater going empty just
as I've soaped up. Now I've got to get out of the shower to switch the
valve back from the batch heater to the cistern. THere's got to be a better
way, but without much electricity use (because I'll only have solar power).

Any ideas out there?

----------
> From: Marc J. Rosenbaum <Marc.J.Rosenbaum@valley.net>
> To: greenbuilding@crest.org
> Subject: Re: GBlist: Drainwater heat recovery
> Date: Monday, May 26, 1997 9:05 PM
> 
> Batch heater will be hotter than water with recovered greywater heat most
of
> the time in Colorado - I had a batch heater in my first house in NH.  Put
GFX
> first.
> 
> Also - on demand heater needs to be well-thermostatically controlled to
take
> the variable temperature output of a batch heater.  Beware scalding!
> 

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