Closed pressurized systems - what heat transfer fluid are you using?

[SteveJ]

Just curious what everyone is running in their closed systems with or without storage.

How many have some sort of freeze protection in their pressurized loops?

If using glycol - what type and what percentage?

 

[SteveJ]

So, I am the only one using glycol???

I am alone in freeze protection???

I feel so all alone

Seriously, nobody fears freezing of their system?

Thanks,
Steve

 

[Eric Johnson]

I used glycol for years, but finally decided that better insulation and a anti-freeze strategy was a better longterm investment. Part of my problem is that I have a big, old house with 15 cast iron radiators and large diameter pipe in some places, so I had to use a flat plate heat exchanger between my pressurized wood side, and the pressurized house side, or go broke buying enough glycol to fill the whole thing. I got rid of the glycol and got rid of the hx, and now it works a lot better, efficiency wise.

 

[SteveJ]

Eric,

I have to ask - What is your anti-freeze strategy?

How do you handle vacations? emergencies? etc. when you cannot get to the house?

Thanks,
steve

 

[DenaliChuck]

I'm going to go with water in my system due to the cost of glycol. If we go away I'll load the tank with BTU's, and prep a fire in the firebox to have a neighbor come by and light one off mid-way through our trip. I bet we could easily get through a month of subzero weather. Frozenassets in Fairbanks said his uninsulated tank was losing 2.5 degrees per day and it was completely uninsulated (he was testing his system prior to insulating).

Time will tell if it proves true!

How much is a gallon of 100% glycol anyway?

 

[BrownianHeatingTech]

How much is a gallon of 100% glycol anyway?

If you have to ask, you probably don't want to know...

I buy it wholesale, so I couldn't tell you what retail costs are, but I would guess that quality propylene glycol with a corrosion inhibitor package would be in the be in the ballpark of $20 per gallon.

Joe

 

[BrownianHeatingTech]

How much is a gallon of 100% glycol anyway?

If you have to ask, you probably don't want to know...

I buy it wholesale, so I couldn't tell you what retail costs are, but I would guess that quality propylene glycol with a corrosion inhibitor package would be in the be in the ballpark of $20 per gallon.

Joe

so how much for a 1000 gal storage system? minimum/maximum?

Figure the percentage, and multiply. For 30% glycol, that would be 300 gallons. I presume you could get better pricing in 55-gallon drums. Still, it's going to cost a lot to glycol a tank that big.

Joe

 

[Sting]

And think about what you will do with the liquid if you need to drain for repair or refurbish? Shame to dump all that treated liquid down the city sewer - certainly a drama if your on a rural septic system.

 

[BrownianHeatingTech]

And think about what you will do with the liquid if you need to drain for repair or refurbish? Shame to dump all that treated liquid down the city sewer - certainly a drama if your on a rural septic system.

Glycol breaks down, so you will need to do that every two years, most likely. Maybe a bit longer if you really baby the system (keep the temperatures down, for one).

Glycol is an ongoing expense, not just a one-time thing. In the case of a wood boiler system with a large tank, it could exceed the savings in terms of oil not used, and will continue to increase in price (being a petrochemical).

Joe

 

[DenaliChuck]

I had no idea that glycol needed to be replaced. Are there types that don't, or am I negligent in maintaining my present hydronic system?

 

[Willman]

I had no idea that glycol needed to be replaced.

Even automotive antifreeze needs to be changed. Varying service intervals though.
Will

 

[BrownianHeatingTech]

I had no idea that glycol needed to be replaced. Are there types that don't, or am I negligent in maintaining my present hydronic system?

There are test kits. You can also drain a small amount into a cup and put it in your freezer, for a quick-and-dirty test (since the test kits are pricey).

I'm not aware of any antifreeze that does not need to be changed. Some may last longer than others, but not generally by much.

Joe

 

[Sting]

And think about what you will do with the liquid if you need to drain for repair or refurbish? Shame to dump all that treated liquid down the city sewer - certainly a drama if your on a rural septic system.

Glycol breaks down, so you will need to do that every two years, most likely. Maybe a bit longer if you really baby the system (keep the temperatures down, for one).

Glycol is an ongoing expense, not just a one-time thing. In the case of a wood boiler system with a large tank, it could exceed the savings in terms of oil not used, and will continue to increase in price (being a petrochemical).

Joe

agreed Joe, But don't belittle the environmental impact of dumping 1000+ gal of glycol impregnated liquid in the sump pump to roll out into the neighbors lawn or --- wash out a rural waste water system or worst a simple septic pit that wasn't designed to be choked by that much liquid in a short time. Even an old treatment is still as you describe - 100's of gal or petrochemical laced liquid being dumped.

 

[BrownianHeatingTech]

agreed Joe, But don't belittle the environmental impact of dumping 1000+ gal of glycol impregnated liquid in the sump pump to roll out into the neighbors lawn or --- wash out a rural waste water system or worst a simple septic pit that wasn't designed to be choked by that much liquid in a short time. Even an old treatment is still as you describe - 100's of gal or petrochemical laced liquid being dumped.

Propylene glycol (boiler antifreeze) is a non-toxic substance. It's actually a food additive (for one example, Dunkin' Donuts uses it in many/most of their flavor syrups), and due to its use for protecting domestic water systems from freezing (in vacation homes, boats, and RV's), most anything you can get is going to be food-grade.

Ethylene glycol (automotive antifreeze) is a different story, obviously.

Joe

 

[Sting]

agreed Joe, But don't belittle the environmental impact of dumping 1000+ gal of glycol impregnated liquid in the sump pump to roll out into the neighbors lawn or --- wash out a rural waste water system or worst a simple septic pit that wasn't designed to be choked by that much liquid in a short time. Even an old treatment is still as you describe - 100's of gal or petrochemical laced liquid being dumped.

Propylene glycol (boiler antifreeze) is a non-toxic substance. It's actually a food additive (for one example, Dunkin' Donuts uses it in many/most of their flavor syrups), and due to its use for protecting domestic water systems from freezing (in vacation homes, boats, and RV's), most anything you can get is going to be food-grade.

Ethylene glycol (automotive antifreeze) is a different story, obviously.

Joe

YOU sir should run for office

you describe glycol above first as a "petrochemical" - then flip flop to describing it as a product to make donuts

too funny!

lets dump 1000 gallons of donuts mix out on the lawn - its biodegradable able able

somebody make coffee.

 

[BrownianHeatingTech]

you describe glycol above first as a "petrochemical" - then flip flop to describing it as a product to make donuts

Actually, it's used in the flavor syrups for their coffee.

Anyway, "petrochemical" defines its source, not it's properties. Propylene oxide is derived from oil, then hydrated to form propylene glycol.

Lots of food additives are petrochemicals, or derived from petrochemicals. All that means is that their prices tend to go up when the price of oil goes up.

Joe

 

[Jeff S]

So what is the difference between the antifreeze they sell for RVs and for stuff for boilers?.Is one more concentrated?

 

[jebatty]

I use antifreeze in the boiler (about 55 gallons, 50% mix) and a plate hx to transfer to water in the heating/storage system (1000 gal pressurized storage). Originally did this because I had unpressurized storage with a pressurized boiler; also wanted boiler freeze protection. And, I took out an old OWB with antifreeze (150 gal), and wanted to use some of what I had on hand. Balance is still in storage tank. Haven't yet decided whether to take out the plate hx as whole system now is pressurized.

 

[BrownianHeatingTech]

So what is the difference between the antifreeze they sell for RVs and for stuff for boilers?.Is one more concentrated?

Usually, the RV stuff is pre-diluted, at a 50/50 mix. And it is usually just propylene glycol, whereas the boiler stuff usually has corrosion inhibitors added.

However, always read the label, because any store can be selling either. Caveat emptor...

Joe