Cute idea, but up north here in frost heave country, those copper pipes
wouldn't make it through one winter. PEX, maybe. And you'd have to fill
with antifreeze and use a heat exchanger setup, to keep them from
freezing solid, unless you put them so deep that it was residual ground
heat you were sucking instead of solar.
When I lived in southern Indiana, with abandoned water-filled limestone
quarries all over the place, I had a dream of buying one, and dropping a
heat exchanger on the bottom to get free cooling for a/c. Of course, I
was a broke student at the time, so it stayed in the dream stage.
That reminds me of a funny story I guy once told me. He had lived for
a while in a trailer park in southern Arizona. The service lines to
the trailers were only buried about 6 inches deep, in ground that
baked in the sun all day, so the water supply that came into the
trailer was HOT. This was a problem in that you could not take a
shower without getting scalded -- no cold water to blend in with the
hot. Finally his neighbors clued him in -- the solution was to turn
off your water heater. Then the water in it would cool down to your
air-conditioned indoor temperature and be your cold water supply. -- H
When I read the subject I had to laugh. No one around here would
contemplate the idea. Something about sub-zero temperatures for a couple of
month a year...
But I suppose if freezing is never a concern (even Florida gets an
occasional frost), then go for it.
There is something disturbing about making something that gives you an incentive
to continue to have poor attic ventilation, or even to make your attic
ventilation worse in order to raise the efficiency of the water heating system.
That is like a government basing its budget on having a tax on prostitution.
It encourages the formation of ice dams in the winter, which causes snow melt to
back up under the shingles and leak into the decking, which rots the decking and
rafters, leading to premature roof failure.
Well, for one thing heat is the enemy of shingles--if you don't have
proper ventilation and are in a hot climate they'll very likely fail
Then there's elimination of moisture--without adequate ventilation you
can get enough moisture buildup in the attic to result in mold on the
structure, and where there is mold there is shortly after rot.
Then there are ice dams in winter.
There's a reason that every new roof that goes on in most of the US
has a ridge vent, and the reason is not that it looks snarfy or makes
big profits for the roofer.
OK, for people in your type of climate, the reason against using the attic to
pre-heat domestic water is to limit air-conditioning costs. The money you save
on hot water by using the attic to pre-heat it is more than cancelled out by the
extra money you spend on AC, as compared to what you could have saved by
passively venting your attic.
On Tue, 19 Aug 2008 15:15:13 GMT
---@---.--- (Robert Scott) wrote:
It might be if air conditioning were common here - which it isn't.
Round here the temperature gets below 0 C or above 25 C maybe two or three
times a year - almost a perfect climate, apart from the rain.
What we do in these parts usually is put insulation in the loft so
as to thermally isolate it from the house. In summer it gets hot up there
and in winter it gets cold (range perhaps 5-40 C).
It does strike me that it may well be reasonable to use the loft as
a solar collector here.
-- C:>WIN | Directable Mirror Arrays
The computer obeys and wins. | A better way to focus the sun
Where is "here" exactly?
OK, so if ice dams and air conditioning costs are not an issue with you, then
look at the cost/benefit ratio. You can't run potable water directly through an
automotive radiator, so you are probably stuck with a large number of home
heating-type fin tubes. Without active air circulation, they are going to be
very inefficient, so you will need lots and lots of them just to erase maybe 1/4
of your domestic water heating bill. What do you pay now for water heating?
$15 a month? So you might save $4 a month with your inside attic collector. If
the fin tubes plus installation cost you $1000, then you will just break even
after 20 years.
On the other hand, if you installed a real solar collector outside the roof, a
much smaller unit could deliver more heat, and it could deliver that heat
year-round, instead of just in the summer, as with your in-attic collector.
Most of the heat the falls on your roof gets conducted away by the wind. What
remains has to travel through the insulating properties of the wood sheathing.
Then it has to transfer to air without the benefit of active circulation, then
it has to transfer again into your "collector". A collector on the roof
prevents much of the wind-conducted losses and avoids two air-to-solid heat
transfers. About the only benefit to the inside collector, as was pointed out
by earlier posters in this thread, would be to disguise the collector for
It still is in Storey County, Nevada. In fact the branch of the Feds
that shut it down was the IRS and the charge was tax evasion and the
IRS continued to run it for a while. There was even a "60 minutes"
story on it while it was being run by the IRS (I suspect that the
embarrassment of finding that the US government was running a bordello
had something to do with its being shut down).
And Mustang Ranch is back in operation under new ownership--the land
it was on belongs to the Bureau of Land Management now so the new
owners moved the buildings about 5 miles down the road.
I live in Fl. I had my home replumbed a few yrs ago and the pipes are
in the attic. They wrapped the "cold" water pipe with foam rubber in
case of condensation.
I have to wait FOREVER to get cold water to flow, because the water
sitting in that "cold" water plastic pipe (I assume it's PEX) even
with the foam wrapped around it heats up and gets VERY hot.
I would NEVER purposely plumb a home like that. Hell, I can't even
wash clothes with cold water!
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