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doublebubble · 01-03-2020, 17:25

Hi everyone,

We a couple of refrigeration systems onboard i.e, engine driven eutectic system and a 12v system, we use the eutectic system quite a lot especially when motoring, I have never changed the brine tank solution as it was up and running when we purchased the boat but I would like to drain and refill the brine tank solution just to be sure we are getting the best we can out of the system, but a little confused on what is the best and most efficient mixture to use, we have two tanks each holding 27.5 litres each by volume, anyone with some experience in this field would much appreciated.

Kind Regards
Rod.

billknny · 01-03-2020, 17:28

Why change it? It doesn't go bad...

But, if you must, the first question is, Freezer? or Fridge? It makes a difference.

**a64pilot** · 01-03-2020, 17:36

I certainly wouldn’t, but are you certain it’s actually brine? A mix of antifreeze and water is very common, it’s not I don’t believe a true Eutetic solution, but it’s common.

doublebubble · 01-03-2020, 17:37

Hi Billknny,

It's our day fridge as we have stand alone freezer, the reason for maybe changing it is that I have no idea as to what is in it, hence why maybe change it so that I know what's in the tanks and mixture is right.

Kind regards Rod Lewis.

Uncle Bob · 01-03-2020, 17:43

Quote:

Originally Posted by doublebubble

Hi everyone,

We a couple of refrigeration systems onboard i.e, engine driven eutectic system and a 12v system, we use the eutectic system quite a lot especially when motoring, I have never changed the brine tank solution as it was up and running when we purchased the boat but I would like to drain and refill the brine tank solution just to be sure we are getting the best we can out of the system, but a little confused on what is the best and most efficient mixture to use, we have two tanks each holding 27.5 litres each by volume, anyone with some experience in this field would much appreciated.

Kind Regards
Rod.

Can't tell you as I don't know, however Peter at Ozefridge will know as he makes them and he will give you the information you need. Just down in Victoria as well

ozefridge@ozemail.com.au

doublebubble · 01-03-2020, 17:51

Thanks, I'll contact ozefridge and see what he thinks.

Cheers Rod

Richard Kollmann · 01-03-2020, 20:58

Quote:

Originally Posted by doublebubble

Hi everyone,

We a couple of refrigeration systems onboard i.e, engine driven eutectic system and a 12v system, we use the eutectic system quite a lot especially when motoring, I have never changed the brine tank solution as it was up and running when we purchased the boat but I would like to drain and refill the brine tank solution just to be sure we are getting the best we can out of the system, but a little confused on what is the best and most efficient mixture to use, we have two tanks each holding 27.5 litres each by volume, anyone with some experience in this field would much appreciated.

Kind Regards
Rod.

Dole eutectic plates are the only plates using brine solution I know of. To prevent corrosion they use a cocktail chemical of additives. In addition the they vacuum expansion air space and refill with dry nitrogen. Finally they weld fill plug tight.

Glazier Bay and Frigoboat experimented with super mixtures.

Most other companies for safety reasons used food grade Propelene Glycol water mix.

There are two reasons you would question condition of eutectic solution is loss of some solution do to leak in tank indicated line around plate where frosted area indicates solution level in plate. The second problem with glycol is over time the heaver glycol will settle to bottom and lighter viscosity water will rise to the top.
This separation if present reverses the normal frost formation on outside of plate from appearing at the bottom first and after separation frosting first from top down. I have always believed motion of boat will allow solution to combine again.
There is no preventive maintenance on eutectic solution so if it isn't broke don't try to fix it.

The main concerns for the design of eutectic plates is for internal solution leaking into refrigerant experienced usually by someone tampering with proven non corrosive solutions. This usually show up in structural deforming plate.

GILow · 02-03-2020, 03:52

Quote:

Originally Posted by Uncle Bob

Can't tell you as I don't know, however Peter at Ozefridge will know as he makes them and he will give you the information you need. Just down in Victoria as well

ozefridge@ozemail.com.au

Yes, Pete recommends two different concentrations of coolant for his systems depending on whether you are running them as a fridge or freezer. I have been scratching my head trying to remember what these were but I’ve gone blank.

Anyway, the red/pink coolant is available in decent container sizes from Repco/Autobarn/Supercheep etc.

Edit: I just found the soft copy of the manual he sent me. He uses 10% glycol for fridge systems and 30% for freezer systems.

**a64pilot** · 02-03-2020, 05:53

If it’s working, don’t break it.
I would see no harm in changing it if you were sure you knew what was in there, knew the mix and could replicate it, but not knowing what is, could be an issue.
It’s not like radiator coolant that does break down and become contaminated.

Richard Kollmann · 02-03-2020, 06:24

Quote:

Originally Posted by GILow

Yes, Pete recommends two different concentrations of coolant for his systems depending on whether you are running them as a fridge or freezer. I have been scratching my head trying to remember what these were but I’ve gone blank.

Anyway, the red/pink coolant is available in decent container sizes from Repco/Autobarn/Supercheep etc.

Edit: I just found the soft copy of the manual he sent me. He uses 10% glycol for fridge systems and 30% for freezer systems.

Glycol and water is not a true eutectic as melting occurs slowly and, temperature slowly rises unlike frozen water where as long as some ice remains in container temperature will remain at 32 degrees F.

Another point to remember is four ounces of Ethylene Glycol in food from leaking plate is lethal.

Eutectic solution freeze points vary from one product to another so if you are doing your own mixing I recommend testing a sample first. Professionals use a hand held refractomitor to determine solutions freeze point. You can fill a plastic bottle with the solution mix you think is correct and place a pocket thermometer in bottle then place it in a freezer set colder than your intended eutectic point. Once frozen take it out of freezer and record temperature increase every five minutes. If test solution temperature is less than your desired freeze point the temperature will rise quickly to its freeze point. Now as this is not a true eutectic the temperature in ice will rise at a slow rate.

There is always temperature and energy losses between frozen solution and temperature inside refrigerated box so refrigerator plate solution is normally set to 26 degrees F and freezer plate solution set from zero to +6 degrees F.

Coolerking · 02-03-2020, 07:04

Calcium chloride.
We have built thousands of them.
We can make it change state at what ever temp we like.

https://www.glaciercorp.com/Pages/ev...r.html?pgid=16

RaymondR · 02-03-2020, 10:04

Quote:

Originally Posted by Coolerking

Calcium chloride.
We have built thousands of them.
We can make it change state at what ever temp we like.

https://www.glaciercorp.com/Pages/ev...r.html?pgid=16

They are very nice looking tanks.

I was favoring Calcium Chloride as the eutectic solution for a system I am planning for my boat with copper coils in SS tanks but have been unable to find much in the way of corrosion potential for that arrangement.

I guess if you folks have made and sold thousands of them it's not a problem.

It does beg the question as to why people use alcohol/water or glycol/water mixes when a true eutectic solution in calcium chloride is readily available and cheep.

I think there are a number of types of glycol one of which is not poisonous.