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<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=750563301-15032012>I
think it's a bit more than that. The mass of fluid, little as it is, may
get so cold under night-sky radiation that it freezes and wrecks the collector.
</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=750563301-15032012></SPAN></FONT> </DIV>
<DIV><SPAN class=750563301-15032012></SPAN><FONT face=Arial><FONT
color=#0000ff><FONT size=2>D<SPAN class=750563301-15032012>raining back into
1000 gallons doesn't seem such a good idea, hardly worth the effort, and neither
fish nor fowl. </SPAN></FONT></FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT color=#0000ff><FONT size=2><SPAN
class=750563301-15032012></SPAN></FONT></FONT></FONT> </DIV>
<DIV><FONT face=Arial><FONT color=#0000ff><FONT size=2><SPAN
class=750563301-15032012>But if it was viable, I guess swimming pool treatment
would suffice. Maybe that's what clorox is.</SPAN></FONT></FONT></FONT></DIV>
<DIV><BR></DIV>
<P><FONT size=2>Nick Pyner<BR><BR>Dee Why NSW </FONT></P>
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<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B>
greenbuilding-bounces@lists.bioenergylists.org
[mailto:greenbuilding-bounces@lists.bioenergylists.org]<B>On Behalf Of
</B>Clarke Olsen<BR><B>Sent:</B> Thursday, 15 March 2012 12:16
PM<BR><B>To:</B> Green Building<BR><B>Subject:</B> Re: [Greenbuilding] new
solar heating system in this country<BR><BR></FONT></DIV> The
reason to use a drain-back system is to not have the mass of fluid in the
collector get so cold overnight.
<DIV>The collector will, of course, be ice-cherry-cold, but it should warm-up
faster when empty. I am setting up a</DIV>
<DIV>system where I intend to drain-back into a 1,000 gal tank, skipping the
heat exchanger. </DIV>
<DIV>The concrete tank is enclosed in 10"+ of foam, in the hope of
year-round storage. </DIV>
<DIV> Question: What could I use to suppress
possible organisms from growing in that hot, dark soup?
Vinegar? Clorox? </DIV>
<DIV>The water will remain in that unpressurized system: domestic heat
& water will be through heat exchangers in the tank.</DIV>
<DIV><BR></DIV>
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