OWB into 1 pipe steam system?

[Dill]

Howdy, I'm looking at purchasing a new place. And am hoping to install an OWB since I'll have 128 acres of woods and not a single oil well. One concern that just popped up. The house has steam heat with a newer steam boiler running old cast iron radiators. Which I just checked this morning and they are 1 pipe radiators. Taking to my heat guy, he says its hard to retrofit a return line into old radiators.
So ideas? Is there a steam OWB?

Details on the new house, its huge and old, 4200 sq ft not really insulated, currently sucking up 1300 gallons of oil annually for heat and hot water.

Thanks

 

[jharkin]

I cant comment if there are any steam OWBs... I doubt it but the boiler experts will have to chime in.

Your heat guy is right to warn against a conversion. Its not just the difficulty of running the returns. You also have pipes and radiators that have been there for a hundred years handling only 1 or 2 PSI. Hit them with 50 PSI water and leaks are likely. AND there is the issue of stirring up all the rust and sludge in the bottoms of those rads. AND once converted you might find the radiators are undersized for the heat load - though probably not as they would have been sized originally fo ra completely uninsulated and drafty house (the same size hot water radiator at 180F puts out about 70% the heat of a steam radiator at 212F).

Another site to checkout is the heatinghelp.com forums. There area few very knowledgeable steam pro's there, and the site owner has some great books on steam system operation and maintenance.

 

[pybyr]

If I remember correctly, WoodGun makes a steam-capable wood gasification indoor boiler.

No OWB would be able to run steam- you just couldn't do it over distance through the intervening cold ground, etc.

A steam system that was designed correctly and installed correctly and that hasn't been botched up with uninformed changes over the years is not a bad system. A botched steam system is dreadful on both comfort and efficiency but a well-done steam system is a thing of miraculous elegance of physics and performance. Get someone who really knows steam to take a look. If you have no one nearby, I know of a guy here in VT who is a real "Steam Man" - drop me a note.

If you opt to go away from steam, some of the older 1-pipe radiators can be converted to 2-pipe, and you could run PEX so as to have fresh supply and return lines. Or just give me all your cast iron radiators

Any of the decently engineered high efficiency wood boilers are going to kick the proverbial pants off of nearly any OWB with more heat with less wood. Even with lots of wood acreage, your time and trouble add up. When you're going to a huge investment not only with the boiler but with the install, might as well get something that's reasonably close to best-reasonably-available-efficiency.

 

[Clarkbug]

Im surprised that you are only burning 1300 gallons of oil with a house that size with no insulation....

I would agree that you shouldnt try to convert it, since steam heat is nice. If you are sold on going with wood, I would say re-pipe, or if you have access, install radiant floor heat instead. That can use an indoor or outdoor wood boiler, makes good use of storage, feels good on your feet, and depending on what your plans are for the house it may fit into your remodeling plans.

 

[Dill]

Must be the rain I didn't expect this many replies so fast thanks.

I really don't want to renovate much, my wife and I both grew up in 1700's colonials, she spent her life renovating while I enjoyed a floor that you could race matchbox cars down.
Yes I'm pretty stuck on wood, have always burned wood, no sense stopping this early.
Its 1300 gallons at low temp plus 2 woodstoves currently.
There isn't a whole lot of basement but if the indoor ones are the best bet I could go that route.

 

[jharkin]

Clark makes a good point, 1300 gal inst bad for that size house in your climate. I'm at 1400ft2 and I go through 1200 therms of gas for heat and dhw, which would equal about 850 gallons of #2. I supplement only part time with wood, less than 2 cord a year. I also run 1 pipe steam with a modern 83% eff boiler. You are heating 3x the sq ft with less than 2x the fuel.

An interesting read no matter what you end up doing... Ive read this book cover to cover and its been a big help living in 2 different houses with steam.
http://www.heatinghelp.com/products/Steam-Heating-Books/25/68/Lost-Art-Of-Steam-Heating

 

[heaterman]

If you would, please post a picture of your radiators so we can tell you if they are usable with hot water.

That being said........1300 gallons of oil for a house such as you describe is not bad. You would probably be better served spending the money for a wood boiler on insulation, sealing and windows instead.

The advise given above about possible issues when converting from steam to H/W is very good and should be taken seriously.

 

[Frozen Canuck]

Just out of curiosity what are you spending for the 1300 gallons of oil each year. Decent place to start to see if/when you will have an ROI on a conversion.

 

[Dill]

Well oil is 3.50 something a gallon right now.
This is mainly sticker shock. Our current log cabin burns 300 gallons of oil for heat and hot water annually plus 4-6 cords of wood.
Thanks for the replies guys.

 

[bpirger]

I think steam systems are incredibly "cool".... Here's a thought. Could you use wood to "preheat" the water in the boiler so there'd be less oil usage? I'd think that would be relatively easy to plumb into the system, right at the boiler, but it might not be very pleasing as you'd still be burning oil AND spending all the money for the boiler and doing the work....but a thought.

 

[ewdudley]

I think steam systems are incredibly "cool".... Here's a thought. Could you use wood to "preheat" the water in the boiler so there'd be less oil usage? I'd think that would be relatively easy to plumb into the system, right at the boiler, but it might not be very pleasing as you'd still be burning oil AND spending all the money for the boiler and doing the work....but a thought.

Unfortunately you'd be up against the the 'cool' thing about steam, namely the heat of vaporization.

We could preheat the condensate return from, for example, 120 degF to 180 degF and add 60 btu per lb of mass flow, but then we'd need another 32 btu per lb to get to 212 degF and another whopping 970 btu per lb of enthalpy to get wet steam. So preheating would only get us on the order of 5% of what we need.

 

[bpirger]

Wow, that is an amazing thing to actual stop and realize....5 times the energy to turn into steam as opposed to the heat from ice to boiling. That's why steam dumps so much heat on a radiator eh, the same energy coming back when it condenses.