Anti freeze for solar

mark s

Thanks for all the info.
I am in NE PA and trying to find a product my local supplies will stock.
This is becoming a project just to educate them on solar systems.
Has anyone used a tankless coil on an oil boiler as a dump for the system?
I am using a PAW flowcon C+ station and 3 way valve with a 30 tube collector and 80 gallon Vaugh solar tank.

mark s

What manufactures make anti freeze rated for a closed loop vacuum tube a domestic watermheating system? PH needs to 8.

Paul Pollets

Either...

Viessmann Tyflocor (pre-diluted to -20 protection) or Dow Frost (Undiluted)

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hot_rod

For evac tubes be sure

you select a HD, heavy duty fluid. These have higher operating temperatures, better inhibitors.

hr

Mike C._4

solar antifreeze

There's also Noble and Rhomar (which I use) as many others. You need to use the propylene glycol HD versions (if incidental potable water contact is an issue) i.e. the ones with the more inhibitors in them. Don't use automotive type. Ironically, most are rated for up to 325 deg F and not recommended for evac tube installs but there isn't much for a choice. I am not sure about the Tyfocor specs. 50% max mix should be about -28 deg F. Use the least protection that will do the job. It will help with heat transfer and pumping. Clean your system good and if you mix use distilled water.

Mike

mark s

Thanks for the info. My local supply house quoted Rhogard05 but is waiting for a call back from supplier if this will be ok to use. Does anyone know if this is ok for solar?

Dwight (Rhomar Water Mgt.)

RhoGard in solar

The RhoGard should be ok for your solar system, especially if it contains aluminum or copper. You don't want to use DowFrost with aluminum.

Rhomar also has a glycol similar to DowFrost called EnviroGard ST. It would probably cost less then DowFrost. The EnviroGard has food type ingredients in case you are concerned about potable water contamination.

Dwight

Drew_2

Antifreeze for Solar

Here is a breakdown of some Solar antifreezes. Dow HD and Noburst HD are propylene glycol based. Tyfocor is potassium formate. Propylene glycol is GRAS(Generaly Recognized As Safe) as a food product by the FDA. Potassium formate is not GRAS. All the ingredients in the Noburst HD formula are GRAS.
These issues are important in some areas of the U.S. when solar is used for domestic water heating with a single walled system.

hot_rod

the fluids designed

for high temperature evac tube applications may not pass the FDA approval, as Drew mentioned. Best check that out with some of the import fluids.

This is the type of thing that could give solar a black eye and force more codes to re-examine double walled heat exchangers. Seems just when the double wall restrictions were being re-examined and lifted in areas, along comes another reason for code officials to question solar fluids.

hr

Larry C_13

DowFrost and Aluminum

What is the issue with DowFrost and Aluminum? I used DowFrost in an application with aluminum blocks that are being chilled down to about 10 F.

Larry C

Larry C_13

DowFrost and Aluminum Part II

After talking to Dow, the issue is above 150 F, the inhibators start breaking down.

Larry C

hot_rod

tankless coil

dump is a clever idea. Again, it may not be needed if you have a good year arounf DHW load. That cast boiler could absorb some excess, but it may warm the space where the boiler is located

hr

mark s

I am hoping to get some free btus in the winter by using the tankless coil.We are not home during the day and after we charge the tank we should be able to send that
extra heat into the boiler.
If I set the collector to the winter angle I may not over heat the boiler room in the summer. This is all new to me and I may as well experiment on my own system.