Hi August,
Its what I've been told that using glycol in drainback you will end up
with problems when the fluid hits the super heated metal in the
collectors.
Very hard on the chemistry, shortens the life etc.
So PH neutral water only,
jay
peltz power
On Apr 24, 2009, at 10:38 AM, August Goers wrote:
Darryl -
I've always heard that it isn't good to run glycol in a drainback
system.
When the system drains during an overheating condition there is a
glycol
residue left in the collectors which cooks and I suppose turns to
powder.
Time after time this will decrease system efficiency and possibly
degrade
the glycol inhibitors.
Tom Lane, thoughts?
Best,
August
August Goers
Luminalt Energy Corporation
O: 415.564.7652
M: 415.559.1525
F: 650.244.9167
www.luminalt.com
aug...@luminalt.com
-----Original Message-----
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Darryl
Thayer
Sent: Thursday, April 23, 2009 4:45 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Heat dump or Stagnate?
Hello
I have done many drain back systems with very little failure. I
usually
think it is in the subtleties in the piping/pumping loop when a freeze
occurs. So if you are to drain back, use only water.
I have done many antifreeze systems with ethylene glycol and have had
corrosion in the piping if the antifreeze is not changed. I have had
systems run for more than 10 years before the system has a corrosion
leak.
I have never done a antifreeze drain back system. However they seem
to be
more popular as time goes on. This is of course a sealed drain back
with
anti-freeze instead of water. Then if your piping or pumping loop has
design problems you will not freeze. It would sure be possible to use
nitrogen or argon as a cover gas to prevent oxidation of the anti-
freeze and
acidic corrosion of the piping/collectors.
Darryl
--- On Thu, 4/23/09, Troy Harvey <tahar...@heliocentric.org> wrote:
From: Troy Harvey <tahar...@heliocentric.org>
Subject: Re: [RE-wrenches] Heat dump or Stagnate?
To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org>
Date: Thursday, April 23, 2009, 1:10 PM
Apparently this is the "modern" design method used
in many european systems. It scares me too. But from several
sources, this seems to be considered one of the most
reliable design methods for closed loop systems (ie. it
works even without electronic controls working, power
outages, etc).
Standard glycol. The main point seems to be the design of
the pipes and collectors need to facilitate collector
draining from the steam pushing the fluid back into the
expansion tank, so the collectors empty themselves. Its
closed loop, but effectively becomes a "pressurized
drainback" in over heating conditions.
Here is a couple of links:
http://www.aee-intec.at/0uploads/dateien48.pdf
http://www.suterconsulting.com/CISBAT.pdf
I'm hoping to find someone with experience with this
kind of system to overcome my fears
Troy Harvey
---------------------
Heliocentric
801-453-9434
tahar...@heliocentric.org
On Apr 23, 2009, at 11:04 AM, Dana wrote:
I have only seen boiled glycol turn to a cola like
syrup that had to be
purged and removed.
What kind of system & glycol is this?
Where would you expand that much?
Can you provide a link to this paper?
We use heat dumps.
Dana Orzel
Great Solar Works, Inc
www.solarwork.com
E - d...@solarwork.com
V - 970.626.5253
F - 970.626.4140
C - 970.209.4076
"I'd put my money on solar energy. I hope we
don't have to wait 'til oil and
coal run out before we tackle that."
-Thomas Edison, in conversation with Henry Ford and
Harvey Firestone, March
1931
-----Original Message-----
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On
Behalf Of Troy Harvey
Sent: Thursday, April 23, 2009 10:43 AM
To: RE-wrenches
Subject: [RE-wrenches] Solar Combi-systems: Heat dump
or Stagnate?
I'm wondering how many of you out there have
installed medium sized
solar hot water systems (6-8 panel) that were designed
to stagnate
during summertime over production as opposed to
diverting to a heat
dump or radiator? The International solar agency has a
couple of
papers that show a properly designed system should be
able to stagnate
in a way that the boiling glycol mix vapors in the
panels, purge the
panels of fluid, turning off the system without
degrading the glycol.
That doesn't seem to be a typical way to design
systems in the U.S. ,
we've usually gone to a heat dump. Does anyone
have experience with
this?
Troy Harvey
---------------------
Heliocentric
801-453-9434
tahar...@heliocentric.org
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