ice banks ?

Submitted: Thursday, Feb 12, 2004 at 17:04
ThreadID: 10483 Views:2745 Replies:5 FollowUps:12
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Who knows the correct water to metho % to create an " ice bank " as used in euteric refridgeration , and how much longer at a given temperature would said ice bank last compared to normal block ice of the same litreage ????
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Reply By: Member - Eskimo - Thursday, Feb 12, 2004 at 18:22

Thursday, Feb 12, 2004 at 18:22
so you dont know how to keep beer cold eh? I feel sorry for your mates!! lol

The brine is actually a solution of ethyl alcohol and water. Water when freezing expands while the brine (when at correct concentrations) does not. This stops the container holding the brine from splitting whereas water keeps expanding the colder it gets and will fracture the container unless its made of sufficient thickness to resist but adds considerably to weight.

For example ..a 1/2 copper pipe used for domestic water will split when frozen at around -7C.
Ice banks are used in times of obtaining cheap power. Utectic as used in boats does the same...from times when they run the diesel to charge essentials such as batteries etc etc.

Of course a large supply of solution lasts longer than a small one. but generally speaking etheyl alcohol solution will not last any longer than ordinary ice.

The tanks holding the brine must be stainless and must be sealed Air Tight to prevent the alcohol from evaporating.Wow, am I cute! The extra long legs are built-in prevention against ducks disease. Great looks and a real goer. Doesnt waddle along like some.
AnswerID: 46484

Follow Up By: Member - Eskimo - Thursday, Feb 12, 2004 at 18:44

Thursday, Feb 12, 2004 at 18:44
the % rate is really dependent on how cold one needs to get the brine while still having a solution and not freezing it. Boats generally use a mixture of 60 parts ethyl alcohol to 40 parts waterWow, am I cute! The extra long legs are built-in prevention against ducks disease. Great looks and a real goer. Doesnt waddle along like some.
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Follow Up By: ThePublican - Thursday, Feb 12, 2004 at 18:48

Thursday, Feb 12, 2004 at 18:48
Eskimo,,I have all the cold beer that anyone would ever want,, Im after the formula as a % water to metho that when frozen in a sealed container [such as a 2/3ltr orange juice bottle or an empty wine bladder] supposedly lasts longer than frozen straight h2o at any given temp,,,just as salt spread on ice in an esky lowers the effective temp.
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Follow Up By: Member - Eskimo - Thursday, Feb 12, 2004 at 19:04

Thursday, Feb 12, 2004 at 19:04
I dont think ethanol and water will give you want you want.
I think you want those real Utectic soltions (very very salty salty) like lithium bromide. There are others as well but i cant recall any at the momentWow, am I cute! The extra long legs are built-in prevention against ducks disease. Great looks and a real goer. Doesnt waddle along like some.
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Follow Up By: Member - Eskimo - Thursday, Feb 12, 2004 at 19:08

Thursday, Feb 12, 2004 at 19:08
salt spread on ice in an esky lowers the effective temp. what?
how do we get free refrigeration from just adding ice?
Wow, am I cute! The extra long legs are built-in prevention against ducks disease. Great looks and a real goer. Doesnt waddle along like some.
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Follow Up By: GaryInOz (Vic) - Thursday, Feb 12, 2004 at 20:00

Thursday, Feb 12, 2004 at 20:00
"...I dont think ethanol and water will give you want you want...."

It will however give you a very severe headache..... ;-)
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Reply By: Member - Captain (WA) - Thursday, Feb 12, 2004 at 19:10

Thursday, Feb 12, 2004 at 19:10
A simpler solution is to use a salt in place of the ethyl alchol. Its far cheaper and most importantly you probably already have it in the pantry! The easiest way to use it to fill several say 2l orange juice containers and freeze in your home freezer.

An 18% (by weight) salt solution will freeze at -15C. What this will do for you is keep your esky colder, but typically not for any longer.

As normal ice melts at 0c, you will find the esky can only be 0c at its coldest, but typically 2-3C due to inefficienies in insulation etc... With an 18% brine solution, the "ice" wil now be at -15C, resulting in the esky being MUCH colder.

Cheers

Mark

Nissan 2003 GU 3.0TD
Windsor Rapid Offroad
AnswerID: 46493

Follow Up By: GaryInOz (Vic) - Thursday, Feb 12, 2004 at 20:02

Thursday, Feb 12, 2004 at 20:02
But the brine will melt at a lower temp, so make sure it is SEALED TIGHT
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Reply By: Terry - Thursday, Feb 12, 2004 at 22:26

Thursday, Feb 12, 2004 at 22:26
Forget metho, great when it ignites. Get some Tectaloy concentrate (glycol) and mix it to the level of freezing you want to go to. If Tectaloy is a health concern, use ethyl glycol. Most eutectic systems in boats use these solutions.
AnswerID: 46535

Follow Up By: David T - Thursday, Feb 12, 2004 at 23:34

Thursday, Feb 12, 2004 at 23:34
Ethylene glycol ain't that healthy either - I assume you are talking about antifreeze - this will pickle your liver without any trouble at all - in fact the treatment for an overdose of this stuff is ethanol (alcohol)
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Follow Up By: Terry - Monday, Feb 16, 2004 at 22:45

Monday, Feb 16, 2004 at 22:45
My apologies David, that should have been Propylene Glycol which is considered safe. Your quite right about Ethylene glycol it can do some serious damage if ingested.
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Reply By: Camper - Friday, Feb 13, 2004 at 18:17

Friday, Feb 13, 2004 at 18:17
Lots of interesting physics in this one isn't there?
Strikes me that in order to gain the benefits of this idea you would have to make sure that the brine freezes otherwise you will be missing out on the benefits of thermal capacity or latent heat required to bring about a change of state. Apparently it takes 336 kilojules of heat to melt a kilo of ice whereas to increase the temp of a kilo of water 1° celsius only takes 4.2 kilojules even if you are raising it from say 1°C to 2°C.
You'd reckon that melting ice would absorb more heat from the esky and its contents than say raising the temperature of an equivalent amount of brine even 10°
Before putting in too much effort and making too much of a mess in the kitchen you might want to know the latent heat requred to melt frozen brine- the salt might lower the rating for water by heaps.
Just a thought.

Cheers,
Camper
AnswerID: 46619

Follow Up By: Member - Eskimo - Friday, Feb 13, 2004 at 18:30

Friday, Feb 13, 2004 at 18:30
firstly
brine when frozen will expand and probably rupture the container.
now i will read the rest and digest the rest!Wow, am I cute! The extra long legs are built-in prevention against ducks disease. Great looks and a real goer. Doesnt waddle along like some.
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Follow Up By: Camper - Friday, Feb 13, 2004 at 18:44

Friday, Feb 13, 2004 at 18:44
Oh Sure, but you would leave a little expansion space surely?
Camper
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Follow Up By: ThePublican - Friday, Feb 13, 2004 at 19:07

Friday, Feb 13, 2004 at 19:07
OK,OK ,OK ,,,,,, am not after brine as in salt solutions and for the pickeling of pork,,, am after the ratio of plain old tap water mixed with metho to give a solution that has a frozen temp lower than plain h2o..... any of you lot ever tried freezing straight metho ?? nah cant be done in a home type fridge /freezer ,,,, all fridge mechs please explain !!!!!
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Follow Up By: Member - Eskimo - Saturday, Feb 14, 2004 at 10:54

Saturday, Feb 14, 2004 at 10:54
If you get a copy of Boyles Law or was that Charles Law ...or both???
this will explain why alcohol freezes at a lower temp than h2o

The domestic system is not designed to lower the temp of product much less than -23C

How-ever it is possible to freeze with special refrigeration systems such as cascade using specific refrigerants. Wow, am I cute! The extra long legs are built-in prevention against ducks disease. Great looks and a real goer. Doesnt waddle along like some.
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FollowupID: 308583

Reply By: Member - Eskimo - Monday, Feb 16, 2004 at 18:14

Monday, Feb 16, 2004 at 18:14
Publican
Reading a industry Journal and a brine mix for a new supermarket consisted of 40% wt propylene gylcol. non toxic but should not be drunk and non flamable. Freezes at -21C
inhibited and approved for food stuffs by danish authorities.
compatible with normal metals ...steel, cu, and brass, plastics and elastomers such as PE, PVC, ABS
Wow, am I cute! The extra long legs are built-in prevention against ducks disease. Great looks and a real goer. Doesnt waddle along like some.
AnswerID: 46923

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