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Author Topic: Brine antifreeze?  (Read 7793 times)
Eccentric Dyslexic
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« on: November 27, 2009, 11:25:45 AM »

How do you make this up for a ground loop?  I understand its better than using glycol based anti freezes?

cheers!

steve
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dhaslam
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« Reply #1 on: November 27, 2009, 11:51:41 AM »

I think that the  term 'brine'  is just a misuse of the word in this  context.  It is just a normal  antifreeze mix.    Are  your return temperatures getting down  to freezing  at present?   
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Eccentric Dyslexic
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« Reply #2 on: November 27, 2009, 12:12:01 PM »

about to fill the loop stage ATM, but am expecting flow out to GL to be about 4c, but can ice form inside of the evaperator reducing efficency if i dont use antifreeze?

steve
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dhaslam
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« Reply #3 on: November 27, 2009, 01:10:56 PM »

As far as I know the reason for antifreeze is to  prevent freezing when the system is static.    Once the water is flowing  it won't be freezing except  possibly  on exiting the heat exchanger and of course if the pump stops ice will form.  It cannot freeze when moving.    It is  advisable to  put in some antifreeze anyway.  I presume you can use  ethylene glycol as used for cars and costs about 2 per litre.                 
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DHW 250 litre cylinder  60 X 47mm tubes
Heating  180,000 litre straw insulated seasonal store, 90X58mm tubes + 7 sqm flat collectors, 1 kW VAWT, 3 kW heatpump plus Walltherm gasifying stove
djh
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« Reply #4 on: November 27, 2009, 01:28:16 PM »

Don't the manufacturer of your heat pump provide specifications for the fill?  Presumably as well as not freezing, the liquid should have good heat transfer properties and be compatible with the device from a corrosion point of view.
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Cheers, Dave
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« Reply #5 on: November 27, 2009, 04:52:42 PM »

I agree, I'd check with the manufacturers and just to add to "djh"s reply, some pumps rely on the lubricating qualities of the additive. Not forgetting amongst other things its anti-fungal properties too. The title antifreeze only really describes one aspect of the treatment.

Cheers
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baker
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« Reply #6 on: December 14, 2009, 09:48:15 PM »

i am not a expert
-20 protection
most heat pumps can work down to -10
is is ground loops?  or bore holes
and will be in that area if horizontal ground loops  is the source at the end of winter
if ice starts to form in the plate heat exchanger which it can
it can freeze and split and in turn brake into the  ref compressor
and that is that  sh*tfan
   antifreeze  expensive
polye, antifreeze is poison   caution with/containers/system design
polyg antifreeze is ok 
 
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Eccentric Dyslexic
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« Reply #7 on: December 30, 2009, 12:12:13 PM »

Just an update to this thread, i used car anti freeze in the loops, i am getting out-to-loop temps of -5c so antifreeze is defo needed.  My loops are protected down to -20c as the pressure guages on my HP indicate temps of -20c on the surfaces of the evaporator piping.

steve
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5KW PV, Immersun, 300l tank in UK. 2x20tube47mm panels with TDC3 & 2x 200l Tanks; 14kw Ground Source Heat pump for UFH.   12 x 20tube 58mm panels heating a 12m by 6m pool and the ground loop for the heat pump. ;-)
wrigpm
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« Reply #8 on: September 19, 2010, 11:49:29 AM »

I used Hydratech Coolflow IG in ours

Paul
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Philip R
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« Reply #9 on: September 20, 2010, 09:20:54 PM »

You must not use automotive poly(ethylene) glycol antifreeze in your groundloop. It is highly toxic, not very biodegradable and will contaminate the groundwater should it ever leak out.
If the Environment agency ever found one out about a leak, the result would be likely to be a trip to the Crown court, an enormous fine and a possible stretch inside.

Follow Manufacturers instructions, i.e. use what they recommend, i.e. Polypropylene glycol solution.
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wrigpm
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« Reply #10 on: September 20, 2010, 09:59:46 PM »

Philip

Not sure where you got your info from but the Environment Agency data states:-

# Ethylene glycol is itself Biodegradable
# Ethylene glycol in air will break down in about 10 days.
# Ethylene glycol in water and in soil will breakdown within several days to a few weeks.

It is however, very toxic by ingestion having an oral LDLO of only 786 mg/kg i.e. about 62g will kill you!
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mespilus
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« Reply #11 on: September 20, 2010, 11:25:49 PM »

What's a 'poly' between friends?

http://en.wikipedia.org/wiki/Ethylene_glycol_poisoning

and

http://en.wikipedia.org/wiki/Polyethylene_glycol
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Philip R
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« Reply #12 on: September 21, 2010, 11:11:13 PM »

In answer to the input from wrigpm and mespilus.

I had the view that Ethylene Glycol was much less biodegradeable than your data shows. I stand corrected.
EG in soil/ groundwater can still remain long enough to penetrate water courses. With modern water treatment plant, i.e. activated charcoal filters, found in newer treatment works, the likelihood of it enterring the drinking water supply is very small.

With respect to my comments about the Environment Agency. In my former employment, an incident occurred where a substantial quantity of fuel oil leaked from an underground pipe. Despite a cleanup campaign and an admission to the EA and HSE that the leak had occurred, a trip to the court resulted, a substantial fine was levied and the possibibility of a custodial sentences was also mentioned.

I appreciate that fuel oil and the antifreeze componds are quite different in toxicity and biodegradability. They are still toxic and leaks would not be tolerated.

The "poly" referred to Polyethylene or polypropylene glycols (PPE & PPG). I have seen this in literature about various antifreeze products. Maybe incorrectly labelled and subsequently incorrectly communicated by myself.  However reading the wiki links, it would have been correct to say that PE and PG are the antifreeze compounds, not PPE and PPG, as these are the polyimerised molecules of aforementioned PE and PG used as chemical intermediates for the synthesis of all kinds of products.

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mespilus
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« Reply #13 on: September 21, 2010, 11:58:42 PM »

In addition to the monomers and polymers
of
ethylene and/or propylene glycol

we also have the dimers:

http://en.wikipedia.org/wiki/Diethylene_glycol

(any followers of Bacchus will remember:

http://en.wikipedia.org/wiki/Austrian_wine

I also seem to remember that BAA had problems deaking
with the (glycol containing) run-off from jet plane de-icing fluids.
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mespilus
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« Reply #14 on: September 22, 2010, 12:11:51 AM »

No affiliation with this supplier,
it just scrolled across as a suggestion from Googlemail:

http://www.glycols.co.uk/coolflowdtx.html

supposedly non-toxic ethylene glycol based heat transfer fluid.
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