futurefitting a garage

[Jason_in_AK]

Howdy folks. I've recently finished building a 24x32' garage in interior Alaska. I've got pex in the slab, but haven't hook anything up to it yet. I'm going to install an Toyo OM 180 in it to provide heat since a good wood burning setup is currently out of my budget. I'd like to have the ability in the future to easily pipe heat in from a separate building containing a gassifying burner, (with a sauna built over the water storage, but that's another matter for another time!).

My main question is: How do I go about constructing the current system so that I could quickly and easily hook a piped-in glycol line for wood heat later? At that point, the oil burner will become a backup/emergency heat source.

Also, what ratio of glycol to water would you guys recommend for the system? The conditions here can get super nasty... -70 or lower for weeks on end. The garage is very well insulated though, with r50 ceiling, r34 walls. The foundation itself has 2" of rigid styrofoam under the slab, and 4 inches on the sides. I plan on keeping the garage in the 40s when it's cold out.

Are there brands of glycol that are better than others for radiant heat? My purchasing location options for glycol up here are long drives to Lowes or Home Despot.

Thanks.

 

[Duetech]

The proper glycol (Propylene not poisonous ethylene like in a car) amounts will depend on the actual total amount of fluid capacity of your system and the temperature you are attempting to establish protection against freezing for. If you have a 10 gallon capacity system and you need a 70% glycol content to protect to -70f then you will need 7 gallons of glycol in your system. The glycol you buy should have the correct mix ratios on the container.

 

[Gooserider]

I am assuming that you are going to be running glycol in the system you are putting together for now? If so, the future-proofing is fairly simple. I would make sure the current boiler circulator is relatively close to the boiler. (You might or might not have additional circs for the load, depending on your setup) Make sure there is a flowcheck in the boiler circ, or that one can easily be retrofit later... Put a tee in the lines going to and from the boiler and circ, one on the input and one on the output, with a shutoff and cap on the branches.

When you eventually do your wood boiler setup, have your lines come in with a second pump (w/flowcheck) and attach to the tees so that in effect the boiler and wood system are in parallel, tied to the load at the same points.

This allows a bunch of control options, but essentially they boil down to having the wood setup feed the load using it's pump if it can, with the fossil boiler kicking in and feeding with it's pump if it can't. Which ever pump is running the flow check prevents backfeeding the non-running pump and boiler.

For the glycol, you'll have to pick the mix that is rated for your climate, but I notice that most of the component spec pages I see seem to say 50% glycol is the max that they are rated for - not sure how low that is for temps. I would say that for brands and mix ratios, it might be best if you can talk with your local Heating Co. types and see what they suggest - they probably have far better experience and qualifications to make recommendations than those of us from more sultry climes that only get down to the minus single digits on rare occasions... :coolsmirk:

Gooserider