A remote wood heater for my work shop

[Qweaver]

I have a 40' multi bay concrete floor shed that I'd like to close in, insulate and heat with a small wood boiler set beside the shed.  That way I could heat only the area that I am working in or all of it. Easily Doable??  What brand should I look at?  What cost should I expect to pay for such a system. 

Each bay would need it's own heat supply or maybe just 2 outlets to heat 2 bays each.  I have a wood working, welding, general mechanical and 2 open storage and general use bays.  A great workshop but just too cold in winter.

Putting a stove in each bay just takes up too much room and I'll spend too much time tending fires. Plus it would be really costly to run pellet stoves in 4-5 bays.
Just had a long talk with Trudy at RIS wood heat and a Cen Boiler  Edge 550 with everything to install a system would run just over $10,000 with heat exchangers in four bays.  That's getting a little rich just for occasional heating.

Quinton

[Qweaver]

I wonder how long it will take from cold start to a warm work space?

[Qweaver]

I got my first bid for @ $11,000 for a Central Boiler Edge 550 and four zone heaters and all the other hardware.  That may be about the going price but I have a hard time justifying that much for a system that will get only occasional use.  I'm rebuilding three sports cars and two motorcycles this winter and I will be in the shop most days so it would be nice to heat the entire 4 bays.  Really hard to do with individual wood stoves. 

I don't want to buy an inferior system...but is there a cheaper way to do this?   My Man Cave has room for one car and a motorcycle and it's a great place to work but I'll be welding up frames, fiberglassing, painting etc.  All things that need to be done in the shed.   I may have to just bite the bullet and spend the money. 

[thecfarm]

I noticed the occasional heat part. I would not suggest a boiler,water. Sounds like you may not want to run any heat out there somedays. A forced hot system would be good for occasinal. It will sit there with no worries about a freeze up. Or do you plan on keeping it around 40° and than turn the heat up when you plan to work out there.

[dave_dj1]

I second the hot air system, set it on one end, pipe it overhead to the other end with a return line on the bottom of first bay. Or if you only want to heat one or two, set it behind them, pipe in to a Y and put a return in each bay.
You could always go with electric, ceiling mounted, quick and not too expensive to buy, not sure how expensive electricity is where you are though so that could come into play.

On another note, how cold does it get there? There is always propane too. Or natural gas if that's in your hood.

[hedgerow]

Sounds like the concrete is already in so in floor heat is out. I would spend the wood boiler money on the best spray foam insulation and liner for the building and just use a force air wood furnace with duct work.

[Gearbox]

Just an idea . you could run a OWB and pipe water to 4 hanging circulators with 4 thermostats with shut off switches on the fans . Just turn on the fans on the bays you need . When it is cold I turn off my fan so my OWB will last 10 to 13 hrs. Or you could just turn down the thermostat to 45 .

[Qweaver]

It's an OWB system that I'm looking at.   My wood is free and it lends itself to zone control the best.  Keeping up with two or three wood fires all day is just out of the question.  I can use pellets but that gets really expensive.  These bays will never be air tight or perfectly insulated so burning abundant free wood makes sense.

[dave_dj1]

I think you're missing the point of using an OWB for intermittent use. It will freeze up and burst all the piping/heaters etc.
If you fill with antifreeze you are looking at about a 40% decrease in efficiency not to mention that it will take a while (hours) to bring the system up to temperature on the days you want to use the bays.

[thecfarm]

Or he could keep the firebox filled and just let the water circulate through the pipes and the heat exchangers. I do that in the fall when I want just a little heat. Than when you want to start building,turn the thermostats on. As I said I would keep it about 40°,I suppose there is a thermostat that goes that low,and than just turn it up when you want to start working in there.

[Qweaver]

OK...just talked to a friend that has operated his system for three years and he gave me a lot of good info.  Both he and the dealer that I talked with say that I should always run antifreeze.  My geothermal system runs antifreeze and at least on the Geo system the solution is MORE efficient than plain water.   I would guess  that would hold true for an OWB system also.  I know little about the OWB and just have to go on what I'm told.  A friend that has a system and the dealer seem like a good source of info.  I'm going to study this as much as I can and seek good advice.  He was unsure about how long it took to get usable heat from cold startup but guessed about an hour.  He really likes this way of heating.
Quinton

[pineywoods]

Take a look at an outdoor wood burning hot air furnace. We see them here used to add wood heat to mobile homes...They are avaiable. Down side is that requires ductwork, but flexible ductwork is cheap and works well. No plumbing to freeze, instant heat, put a controlable register in each room.

[Qweaver]

Take a look at an outdoor wood burning hot air furnace. We see them here used to add wood heat to mobile homes...They are avaiable. Down side is that requires ductwork, but flexible ductwork is cheap and works well. No plumbing to freeze, instant heat, put a controlable register in each room.

This may be a good solution for me. I'll take a look.  My biggest point is to make heat that I don't have to tend to often and I can select the area that I want to heat.  Do you have any suggestions for brands to look at?

[gspren]

   I don't believe the part about antifreeze causing a major loss of efficiency, I've run mine without and now with and see very little difference. Get the antifreeze made for boilers.

[WmFritz]

   I don't believe the part about antifreeze causing a major loss of efficiency, I've run mine without and now with and see very little difference. Get the antifreeze made for boilers.

At 30% antifreeze solution requires 10% more circulator capacity over straight water, if I remember correctly.

My dealer tossed a monster pump in to close the deal when I bought my boiler ( Grundfos 26-99).  It's way bigger then I need, but I used it anyway; so antifreeze had no effect on my system. I only have the one pump on the whole system which has about 2500' of in-floor tubing and the boiler supply/return lines.

One positive with an OWB is the the heated water is stored some when the shop isn't calling for heat. As an example, the boiler I'm speaking of is at our cabin. Last week, my Dad left on Thursday with the place at 70°. Before he left, he put a wheelbarrow full of wood in it, then shut the power down. I went up Saturday and got there about noon. The interior temp was down to 59°. I turned the power on expecting the blower on the boiler to kick on... it didn't. When I checked it, the water temp was still around 170° and the wood inside looked like I just put it in.  An hour later the cabin was 65°.

As an experiment, when I was closing up Sunday, I packed the boiler full of 10" blocks of oak. I shut off all the t-stats, but left the boiler power on to maintain its water temp. My Dad will be back up this Saturday and hopefully the firebox will still have wood left and our 300 gallon battery will be ready to pump hot water.

[dave_dj1]

Whether you believe it or not you can not argue with science.
http://outdoorwoodburningboilers.com/boilerWaterChemistry/shouldYouUseAntifreezeInBoiler.shtml
BOILER WATER CHEMISTRY:
Should You Use Antifreeze in Boiler?
Heat Transfer: The ability of glycols of various forms to transfer heat from your home boiler to your home heating system is obviously of great importance. After all that is the purpose of the furnace. Glycol antifreezes certainly do not do this as efficiently as just putting in hot water. Boilers where you intend to use glycol might have to be larger to compensate.

Answer: When sizing a outdoor boiler to the size of building to heat, factor in approximately 15% reduced heat transfer capacity if thinking of using glycol antifreeze. (or better yet use the documentation for the heat transfer fluid you are considering)
So should you use antifreeze in boiler applications? Not if you can avoid it. Your first attempt should be to find alternatives that offer the freeze-thaw protection you need, and only then consider glycol as the answer of last resort.

[sandman]

Take a look at an outdoor wood burning hot air furnace. We see them here used to add wood heat to mobile homes...They are avaiable. Down side is that requires ductwork, but flexible ductwork is cheap and works well. No plumbing to freeze, instant heat, put a controlable register in each room.

This may be a good solution for me. I'll take a look.  My biggest point is to make heat that I don't have to tend to often and I can select the area that I want to heat.  Do you have any suggestions for brands to look at?

buy a used inside wood boiler and a 500 or even better 1000 gallon used propane tank.

put it all in a very well insulated shed attached to the garage.

use the hot water stored in the tank to heat the garage.

you could also move hot air from the shed into the garage too.

depending on your heat loss you could get away with one fire a day once the thermal storage is up to temp.

if you could do all the work this could be done for $2-4k

jim

[Darrel]

My experience with the forced air wood furnace is that the heat exchanger clogs up frequently.  heated a house 2 winters with one and had to clean the heat exchanger every 2 - 3 weeks.  the only way to avoid clogging the heat exchanger was to keep the firebox full and leave dampers wide open so it was always burning very hot.  used up a whole lot of wood that way.

[dave_dj1]

What kind of forced hot air furnace did you have? I have two Fawcettes made in Canada and haven't had that problem. Or are you talking about a water to air heat exchanger in the plenum on a hot air system?

[Wudman]

Take a look at the Englander forced air furnace.  I have been looking at OWB for my home, but just can't justify the cost of a $10 - $12,000 system.  I have settled on the Englander.  I should have it installed in the next month or so.  It has very good reviews and seems to be a pretty simple stove.

Wudman

[Qweaver]

Because I will be using this to heat my workshop it does not have to meet the same standards that I would require for my home. 

[gasman1075]

I have been in the gas business and doing all sorts of heat for almost 40 years. I heated my buddies well insulated shop 3 bay / 16' W X 30' deep with 12" ceilings for occasional use with 3 Enerco Heatstar space heaters mounted up on the back walls about 8' off the floor. He uses them when working on a broken tractor / skidder etc. The space is not balmy by any means but they were cheap to buy ( $3-400 each ) cheap to operate 99% efficient ( LP Gas ) and he only turns them on when he needs the heat to work on something.  We worked on my splitter and it was minus 12 out and we didn't need gloves.  This is in upstate NY and they only heat the mass not the air. 

[DeepWoods]

My shop is 20'x48' and I heat it with an outdoor wood furnace.  No problem at all to keep warm.  But the shop is fully insulated.  It cost me around $2500.00 for the furnace, but I don't have any additional ductwork inside the shop. But you could run a duct to each bay and close off the unused ones.  Depending on the wood, I tend to my fire two or three time a day.  I purchased the furnace locally, but did find others on the Internet.  I also have a propane heater that keeps the shop warm overnight, or above freezing on the days that I don't work in the shop. That way I don't have to worry about all of my paints and finishes freezing if choose to not work in the shop for a few days.