Glycol formula

[FEISTY]

Greetings All !! I have a situation involving beer line chiller units. Systems are self-contained circulating tank glycol chillers that hold approx. 5 gals. of " mix ". My question is as follows.... what would the correct " recipe " be for glycol to water solution ? I am not familiar with these units, there are several diff. manufacturers , but they are relatively the same. I do not know how to get the correct balance so the tanks do not get floating ice chunks in them. Any help would be greatly appreciated. As always, Have a better tomorrow !!! Thanks.

[nike123]

What is your lowest glycol temperature and what type of glycol you use (ethylene or propylene)?

In Coolpac you have Refrigeration utilities group with Heat transfer fluid calculator.

http://www.et.web.mek.dtu.dk/Coolpack/UK/download.html

[p_p]

I used to work on these many, many years ago, we used ethylene glycol at a mix of 50/50 but out of touch as what is used now, all depends on outside temp.
I presume the glycol is used with a plate heat exchanger for the condenser to dump the heat outside by means of a forced air heat exchanger
Manufacturers should be able to correctly advise you better.


PP

[Grizzly]

Feisty.
Basically when adding glycol to water,
You add either to a certain specified % of specific gravity.
So having identified from one of your glycol manufacturers. What percentages of specific gravity will give the level of freeze protection. that you require.
For example say a 30% mix gives protection to -10c. (The temperature at which that concentration of glycol will freeze)
And a mix of say 10% gives protection to 0c.

You would know that if you wish to operate below 0c that you require sufficient glycol added to water.
To read a S.G. of > 10%.
Please note the figures I have quoted are fictional to help explain what I am pointing out.
As I say contact one of your suppliers for the mix percentages required.
To read this you need a refractometer.
See the link below.

http://www.refractometershop.com/usa/index.html

Good luck Grizzly

P.S. If you have floating ice then your mix is to weak. Add more glycol!

P.P.s. Sorry to not have quoted Imperial. but I have worked for so long in Centigrade now, that I struggle with degrees f. But i am sure you know what I am saying. whichever measure you use!

I don't know how much of this they teach nowadays.
But for all the chiller guys out there.
The Glycol mix is very relevant to chiller performance and operating pressures.
(freeze protection point is set with a known % mix.)

[FEISTY]

Thanks to all for the responses. I was able to access 4 diff. manufacturers who, of course, offered 4 diff. opinions of mixture to obtain proper balance. Most temps average 20-23 degrees F. The type of glycol MUST BE PROPYLENE. These units are for use where direct human contact is possible. A big thanks to Grizzly for the calculations. You were right on the nose , especially about the refract. gauge. I have ordered one and will wait to receive it before experimenting with a new branch of business. Again...I thank all for the help. Better days are ahead !!!.

[FEISTY]

Sorry for the afterthought...the issue with the floating ice is familiar to me. It is VERY COMMON that line cleaners are sent out to maintain these systems. All they do is acid flush the lines and clean the taps. If the level is low in the tank, they chug water in to top it off. That is why I am interested in branching out past the " normal " refrigeration service. Customers are suffering from " hit and run " service. We need to make a difference and just do it right the first time !!! Thanks again.