Looking for feedback from folks with glycol filled systems

[mpilihp]

I have a detached garage that has radiant heat loops installed in the concrete floor which is also insulated on the bottom. This was professionally installed, the piping currently is not hooked up to a heat source and is empty. The sides of the floor are not insulated but at the time I was completely uninformed and the contractor obviously was as well in that reguard.

I want to keep the floor heated at a very low temp to (IE above freezing) and then a few weeks in the winter when Im projecting in the garage, bring it up to a comfortable working temp, IE 55-60 degrees. I currently heat it with a LP can heater but laying on 10 deg concrete floor is tough on the body!

Ive read and heard alot of cons of filling a system with Glycol but since I dont want to heat it all the time to a temp id feel safe wont freeze.

So if you have a system with Glycol in it would you mind answering a few questions?

Glycol Survey

- What is your area's expected outside low temperture?

- What ratio of glycol is your system filled with?

- What type of water did you use to fill it? From the Well if so is it hard or soft? Or distilled water?

- What type of glycol solution did you use? IE is is an uninhibited generic type that sells for $25-40 a gallon or a name brand inhibited solution from say Dow like DowTherm or DowFrost that costs aprox $100 a gallon?
Link to these products:
DowTherm or DowFrost
http://www.dow.com/heattrans/prod/glycol/

- How long has your system been running with this current fill of glycol?

- How often do you have to do MAINTENANCE to the glycol and what do you do?

- If you have refilled your system how long did it go on the first batch of glycol?

- What is your heating system components comprised of? IE PEX, Copper, Black Pipe so on....

- Other comments/personal experiences?

Thanks Guys

~ Phil

 

[Robby]

I have little knowledge about propylene glycol. My boiler is just water and chemicals. But, for summer DHW and some heating I installed a 60 evacuated tube solar set up. It requires antifreeze. A local automotive parts store sold "Pet Friendly" antifreeze which turned out to be propylene glycol (100%) with anti corrosion, anti everything for automotive use. $19.99 a gallon. I went to solar supplier and showed them the container. They of course wanted me to purchase from them but could not fault the auto product. I know 29 folks are going to jump on this, but give it some thought. Copper in rad, cast iron, steel, gaskets, rubber hoses, pump lubricant, high temperatures, etc. What is different?? Anyway I used it, so did a bunch of other people who had purchased from same place. Maybe help, maybe not.


Robby

 

[Tarmsolo60]

I have glycol and soft well water in my system, It's been in about 5 years and the ph was still ok this fall when I checked it with an electronic tester. I believe it was about a 50-50 mix and the system contains a cast iron oil boiler, steel tarm, copper, and pex. The Tarm is out in an unattached semi-insulated shop with no other heat that gets down to 20F very occasionally and usually stays just above freezing, never have had a problem.

Now that I'm reading what I'm typing I think I'll check what temp I'm safe too this weekend and finish my insulating.

The glycol is Cryotek -100 and costs me about $58/5 gallons, YMMV on cost.

 

[peakbagger]

Heads up on using home center brands of PEG, they typiacally are a blend not 100% pure. They are designed to keep pipes from bursting rather than flowing in an RV . The other issues is viscosity of the liquid, as the temp gets lower, the PEG gets thicker and that increases the friction loss in the system. Circulator pumps are not known to have very high pump head (discharge pressure) and there is a possiblility that your circulator pump will not be able to start the system from cold as it will not be able to develop enough pressure to overcome the friction loss in the pipe. This may not be an issue if your pipes are buried or in a slab, but it is an issue with my solar hot water system.

 

[mpilihp]

Thanks guys, so RObby how long have you been running your solar system with the pet friendly auto ver antifreeze? Just since this summer?

Tarmsolo60, is this what your using? Looks like its gone up in price since you purchased it 5 years ago, now $100 per 5gal.
http://www.acehardwareoutlet.com/(ldpumsyvecauxbbqgvwhfq55)/ProductDetails.aspx?SKU=4295606

The PDF on it stats its a 70% mix (pre diluted with 30% water) and provides protection down to -60.

Any others? Maybe with a longer term install?

Thanks for the feedback.

 

[steam man]

I only use glycol in my solar system but here are a few thoughts:

-expected outside temp: -25 deg F

-I used 50% which with propylene glycol is about -28 deg freeze, -60 deg F burst protection. Keep in mind most of the components in a hydronic system are not able to go any more in the mix. Mostly seals, relief valves .. etc.

-I use distilled water period. The system was first cleaned with a 1-2% solution of TSP and then flushed to get contaminates out.

-All the pro glycol mixes seem to have a higher concentration of inhibitors than off the shelf automotive type. $20 to $40 a gallon seems to be the normal range. I used Rhomar since it was the most readily available at about $20/gallon. I have never seen $100/gallon or why it would be that high. Keep in mind some are premixed, some are not. Follow directions to get the right mix percentage.

-Thought the system has only run since October, no problems or maintenance yet. The ph and temp protection will be checked soon. The fluid temp has been down to -12 deg F at the collectors. I haven't had any pumping problems due to viscosity but my system can use the storage tank heat to preheat the fluid before the pump when initally starting with cold lines. I expect a 5 year lifespan barring any major overheating.

-The system components are all steel/brass/copper. if you use any aluminum be sure sure to use a glycol rated for that.

-Some advise-use the lowest percentage you can. Glycol will find the smallest leak, especially at threaded connections. The system has to be perfectly tight.

-glycol needs more expansion than water needs to be considered. It also has about 90% heat carrying capacity of water. You may need some adjustments here.

Mike

I have a detached garage that has radiant heat loops installed in the concrete floor which is also insulated on the bottom. This was professionally installed, the piping currently is not hooked up to a heat source and is empty. The sides of the floor are not insulated but at the time I was completely uninformed and the contractor obviously was as well in that reguard.

I want to keep the floor heated at a very low temp to (IE above freezing) and then a few weeks in the winter when Im projecting in the garage, bring it up to a comfortable working temp, IE 55-60 degrees. I currently heat it with a LP can heater but laying on 10 deg concrete floor is tough on the body!

Ive read and heard alot of cons of filling a system with Glycol but since I dont want to heat it all the time to a temp id feel safe wont freeze.

So if you have a system with Glycol in it would you mind answering a few questions?

Glycol Survey

- What is your area's expected outside low temperture?

- What ratio of glycol is your system filled with?

- What type of water did you use to fill it? From the Well if so is it hard or soft? Or distilled water?

- What type of glycol solution did you use? IE is is an uninhibited generic type that sells for $25-40 a gallon or a name brand inhibited solution from say Dow like DowTherm or DowFrost that costs aprox $100 a gallon?
Link to these products:
DowTherm or DowFrost
http://www.dow.com/heattrans/prod/glycol/

- How long has your system been running with this current fill of glycol?

- How often do you have to do MAINTENANCE to the glycol and what do you do?

- If you have refilled your system how long did it go on the first batch of glycol?

- What is your heating system components comprised of? IE PEX, Copper, Black Pipe so on....

- Other comments/personal experiences?

Thanks Guys

~ Phil

 

[Tarmsolo60]

your link didn't work for me.

http://www.herchem.com/products/heatingproducts.html

it's the cryotek -100, they show some other flavors there also. I just bought some from my wholesaler for the price I said. I have a business account with them, maybe you could find a deal at a wholesalers?

 

[mpilihp]

Peakbagger so what type of glycol are you using? what mix ratio? How long has it been in your system and have you had to do any maint to it?

Thanks ~ Phil

 

[delong]

I'm new to posting on this site, but have been reading for about a year. I'm posting now because of the subject. I design and formulate antifreeze/heat transfer fluids.
Here are some of the things you should know about these antifreezes.
They come in all kinds of concentrations; 98%, 70%, 58%, 50%,35%,25% and less. These are the most common. This is why some are less than others.
The antifreeze part of the fluid could be Alcohol, Ethylene Glycol, Propylene Glycol, Synthetics, combinations of these and others.
Another part of the fluid is the inhibitor. Simply, this is the life blood of the antifreeze. It is the protector of the antifreeze and the system that it is used in. There are many formulations because of were they're used. Some are not meant to be used in certain systems.
Good water is very important to the life and efficiency of the system. Good water has two names Distilled and Deionized.
If you have questions, post them or call me.

Drew Longnecker
Division Manager/Engineered Fluids
Noble Company
800-678-6625, Ext. 108

 

[Robby]

Wish I had never said anything! I have used "Pet Friendly" for 1 (one) year. As per manufacturers specs I used softened, filtered water in both boiler and solar system. I never mentioned RV antifreeze. To my knowledge they are based on alcohol.
I mixed at 50/50. Any colder I am not interested in system running, just not bursting or swelling anything.

See attached site: http://www.prestone.com/products/antifreezeCoolant.php#antifreezeCoolant4

Go to Low Tox

I send a sample of boiler water, house circulation water and solar solution to a lab that tests the heating system(s) in large high rise buildings. It is inexpensive. I tested both at 6 months, then 1 year. Annually thereafter. They test for more than just PH. There is 10 different readings they provide me with. I don't know what all of them mean, but they also make recommendation's based on tests. No recommendations so far. The cost of testing is small compared to system cost. If I open the any system I save the "water" and pump it back in, add as little as possible. Each of my systems are independent of each other. Solar heats DHW, two tanks, one dual coil and one ( not hooked up yet) stainless steel sidearm. Boiler supplying hot water to house through 200,000 BTU flat plate exchanger. House, 9 zone, 2 water to air, 7 steel radiators, DHW coil. Designed with expert help, installed by me.

Works!

Adding 1100 gal. storage as soon as frost out of the ground. I am convinced I can make the boiler, maybe 20% more efficient with more storage, but that's a whole different thing.


Robby

 

[delong]

Something I should of mentioned in my last post.
Toxicity. This is defined by many orginizations (FDA, OSHA, FEMA) in different ways. Example; What is toxic to fish is not toxic to dogs, what is toxic to cats is not toxic to humans. Make sure what you are using in a system that can come in contact with potable water can be consumed by humans. You should look for a product that has all its ingredients listed by the FDA as a food product for humans. Use caution when using antifreeze that was not made for your paticular system.

 

[mpilihp]

THis is great info thanks guys. My system with the glycol in it for the garage will be seperated from the wood boiler heating system via a indirect water storage tank, the tank will be part of the wood boiler heat system and filled with water, the garage glycol loop will go through the coil in the tank, this will provide some heat buffering and will also reduce the amount of glycol needed.

I am still contemplating on how to pressurize the system. The pump will be in the basement of the house and much lower, about 8 feet down so there will be pressure at the pump. Im thinking of making a pressurized device that I can fill with glycol apply air pressure to and then open a valve below it to force glycol into the system to the correct pressure. No chance of cross contamination. This will also limit the metals touching the glycol, mainly just pex and copper and very limited black pipe/iron (at pump and indirect tank)


Steam Man, when you say to use the lowest percentage you mean lowest of glycol? ie if I can do a 30% glycol mix is better than 50% for leaking purposes and heat transferability?

Thanks all keep the info coming!

 

[steam man]

THis is great info thanks guys. My system with the glycol in it for the garage will be seperated from the wood boiler heating system via a indirect water storage tank, the tank will be part of the wood boiler heat system and filled with water, the garage glycol loop will go through the coil in the tank, this will provide some heat buffering and will also reduce the amount of glycol needed.

I am still contemplating on how to pressurize the system. The pump will be in the basement of the house and much lower, about 8 feet down so there will be pressure at the pump. Im thinking of making a pressurized device that I can fill with glycol apply air pressure to and then open a valve below it to force glycol into the system to the correct pressure. No chance of cross contamination. This will also limit the metals touching the glycol, mainly just pex and copper and very limited black pipe/iron (at pump and indirect tank)


Steam Man, when you say to use the lowest percentage you mean lowest of glycol? ie if I can do a 30% glycol mix is better than 50% for leaking purposes and heat transferability?

Thanks all keep the info coming!

Yes-go with the least glycol that will do the job for viscosity, heat transfer, and its viscous nature compared to water. Most heating pros will agree to that. If I remember right pure propylene glycol is actually flammable until mixed.

At a head of 8' you should be able to use a cheap drill pump with no problem to get the system pressure you need. Glycol touching metals is not an issue. I've actually used a long garden hose filled with glycol and then pressurized that with air and blown it in to get higher pressures into my solar loop.

Mike


Mike

 

[mpilihp]

THanks for the suggestions good idea on how to fill it.

Phil