wood boiler + storage reservoir questions

Rob Blair

They are nice and would be glad to help you.

Rob

Trevor_3

new wood boiler + heat reservoir questions

Hello all--

this is my first time here

I live in Vermont in an 1830 farmhouse. I've always been a DIY-er, and have heated with wood (with an 1910 technology hot air furnace) for 11 years. But the wood-hot air is an all-or-nothing proposition- meaning that my Thermopride oil burner kicks on in the dark of night and while I am off at the day job, and with oil prices doing what they are, heat costs are going to outstrip my mortgage and drive me to who knows where.

I have access to 50+ acres of wood that I can cut for no cost. So-- I've ordered an Econoburn 150 gasifier wood boiler (www.alternativefuelboilers.com). My plan is to install it with as large a "heat storage reservoir" as possible, to basically run the boiler full-tilt periodically, then draw out of the storage as-needed to heat the house while I am asleep or away.

Having ordered the boiler, my next challenge turns to the thermal storage reservoir (basically a large water tank). Bigger is better in this category, as in anything under 500 gallons is a waste of effort, and 750-1000+ is good. If I can plumb the storage in a direct loop with the boiler, with no intervening heat exchangers, it'll be far simpler all around (I am a BIG fan of Dan H's notations of how the "dead men" did some remarkably sophisticated things in deceptively simple ways. But I also gather from the research I have done so far that modern hydronics with any steel components rely on a closed/ pressurized system in order to avoid corrosion of the ferrous parts of the system.

With that long-winded intro, how much pressure and temperature do I need to attain and maintain in order to drive the oxygen out of the loop water, and keep it out?

Ideally, I would like to have something that resembles a closed but _barely_ pressurized (weight of the water from an elevated expansion tank only) system. Am I on an OK track or looking for trouble with corrosion

MANY thanks; I always wanted to be a plumber when I was a kid, and I don't do it for a living now, but I've done a lot of plumbing work- it's just that these factors of hydronics are a whole new learning curve that I am having to surf on this project- fun to learn, but with the $$ involved, I don't want to get it wrong!

Don_189

heat storage

Also worth checking out the hearth.com forum - lots of people doing exactly what you want to do.

http://www.hearth.com/econtent/index.php/forums/viewforum/21/

Don

Jamie Hall

It's not so much

a matter of pressure and temperature to drive out oxygen; it's makeup. You're basically on the right track -- the pressure from an elevated expansion tank will do very nicely, and any temperature much above 120 F should too. Provided. And it's a big provided. You do NOT add water to the system. Every time you add water, you add oxygen with it. So makeup water will kill you. Which basically means leaks or evaporation will kill you.

That help?