[RE-wrenches] Heat dump or Stagnate?

[jay peltz]

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
> august at luminalt.com
>
>
> -----Original Message-----
> From: re-wrenches-bounces at lists.re-wrenches.org
> [mailto:re-wrenches-bounces at 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 <taharvey at heliocentric.org> wrote:
>
>> From: Troy Harvey <taharvey at heliocentric.org>
>> Subject: Re: [RE-wrenches] Heat dump or Stagnate?
>> To: "RE-wrenches" <re-wrenches at 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
>> taharvey at 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 - dana at 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-bounces at lists.re-wrenches.org
>>> [mailto:re-wrenches-bounces at 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
>>> taharvey at heliocentric.org
>>>
>>>
>
>
>
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