Diy wood/water furnace?

[gotmuddy]

Has anyone ever made one for an rv? They are all over the place around here and I thought it would be a great idea. My wife thinks having a woodstove is too hillbilly so I am looking for viable alternatives.

[gotmuddy]

I dont think I explained myself correctly. I want to use a wood stove to heat water that then runs through a heat exhanger. The wood stove would be jacketed with water. This would allow the stove to be outside the cabin and also be much more effecient.

How many hours will a rv type furnace heat a bus on a 20lb bottle?

[paul iossi]

I think lady franklin is using in floor radiant heat, I'm not sure what his plans are for heat, but it will be well researched and thought thru.

[paul iossi]

I'm not a wood heat fan because i don't like the mess in the house, but radiant/water heat is real comfortable, I like warm floors. their are many versions of remote boilers for home use where the mess remains outside that burn wood, pellets, corn etc they typically only need to be fed 2 times a day.
automatic fossil fuel backup is available,
they can be used as direct radiant units or with a liquid/air heat exchanger for forced air,
with pex tubing for floor plumbing and a little care in the build process the only joints are at the manifold/control connections,
pump uses the same amount of electricity that a fan does,
with heated floors the heat is in the floor and naturally rising into the living space, not at the ceiling needing to be blown down to where the people are,
initial system costs are simlar,

[gotmuddy]

Originally Posted by Smitty

lol, no, you didn't My thoughts:

Going out in the rain/snow to load.

Radiant heat = possible leaks

Leaks = No heat & PITA repairs

Additional cost

Electric required for pump

Glycol solution required to prevent freezing

Better insulation necessary

How would the stove being outside make it "more efficient"? More heat required to overcome winter temps, heat requred to transfer from heat to water to interior as opposed to from wood to interior.

That's just a few.....
Smitty

Outside wood furnaces are the most efficient way to heat a home here. You load it with wood twice a day, compared to the regular wood stove in my house 4 times a day, 5-6 if its really cold

The main reason I want it is to save space in the cab and keep the wood outside. I dont care if its raining or whatever when I load it. We are using this bus for going to 4-wheeler rides so hopefully it wont be raining too much.

[lapeer20m]

Originally Posted by gotmuddy

Outside wood furnaces are the most efficient way to heat a home here. You load it with wood twice a day, compared to the regular wood stove in my house 4 times a day, 5-6 if its really cold

The main reason I want it is to save space in the cab and keep the wood outside. I dont care if its raining or whatever when I load it. We are using this bus for going to 4-wheeler rides so hopefully it wont be raining too much.

i respectfully disagree! Outdoor wood boilers have advantages....epecially when it comes to heating multiple buildings, but outdoor boilers are probably the least efficient wood heating device when it comes to heating a single space ie: a house or a bus. Their efficiency numbers are not good at all. This guy http://www.woodheat.org/technology/outbobpen2.htm claims to get 22% net delivered efficiency with his outdoor wood boiler. That pretty much means that for ever 4.4 pieces of wood he loads into the boiler, only 1 of them actually heats his house, the rest are wasted as unused heat. Having a wood stove in the same room you are heating is much superior when it comes to efficiency.

Another reason wood boilers are not efficient is that the fire box never gets that hot because it's surrounded by water and a cold fire box makes for inefficient burning, and they also tend to make a ton of smoke compared to a typical woodstove

i'm not at all opposed to a diy outdoor boiler for a bus, but it'll use a ton of wood for the amount of heat it produces.

I actually made a small boiler a few years back for heating jacuzzi water. I should take some photo's of it. It's a little too small for a good wood fire. I used a 500K btu propane burner in it, but it was basically just a scaled down model of your typical outdoor boiler.

i think a small household fuel oil boiler is an excellent idea for heating a bus. You can get nozzles that are rated for less than 0.5 gallons per hour of continuous operation. you can suck the fuel right out of the buses fuel tank. It wouldn't run all the time, so you would use a pretty small quantity of of fuel in a day. Heated floors would rock! I found a great boiler on craigslist for cheap. i also found 3 broken ones for free and was able to make one usable boiler from the parts. It's my favorite way to heat jacuzzi water when the engine is not running.

Don't let any of us tell that you can't do somehing. if you want to build a wood boiler, i think that finding two cylinders, one that fit's inside the other would be a good place to start. Perhaps mounting a 30 gallon drum inside of a 55 gallon drum, or using a 100 pound propane cylinder mounted inside a 30 gallon drum. The outer drum could hold water, and the inner one could be the firebox. You'd need to weld a chimney and a door into the contraption, and insulate the outer water jacket....i think you could build one for pretty cheap out of scavenged materials. Take lots of photos and let us know how it turns out.

[elkoskoolie]

IF you have a front engine, I think the best plan would be to build a "porch" on the back. Put the stove and wood supply out there. You'd need a railing/ retaining wall with re-located lights. I'd consider a roof, or some way to limit weather on the stove; I'm thinking hot stove + rain = corrosion. Also keep your wood dry.. Set it up right, and you should be able to open the rear door, stay mostly inside to load wood into the stove (if you had a small amunt inside the bus)! Make sure the stove door opens in an appropriate direction.
Good luck!

[swinada]

Another reason wood boilers are not efficient is that the fire box never gets that hot because it's surrounded by water and a cold fire box makes for inefficient burning, and they also tend to make a ton of smoke compared to a typical woodstove

well i disagree on that one, some inferior quality boilers might do that however mine only smokes when it has been sitting for a few hours without any demand for heat, then it will smoke for a minute or two during start up but then it burns pretty clean again.
yes they do burn a whole bunch of wood, but you dont have to split firewood anymore, just cut 4 ft lengths and your ready to go.
Now this is a big unit for heating a house, shop pool etc.
i dont know how you would be able to toad that along for a bus unless you mount the whole thing on a trailer and pull it along. You could have firewood on the trailer too. Connect the lines with some quick couplers and shut off valves, if your planing on living fulltime in your bus i defenetly would be thinking that way. Just for the occasional camping trip i woulnt bother.
also someone mentioned that the install cost is similar to a conventional system, sorry to burst your bubble but that is not so. if you design and install a proper hydronic system you will be looking at 2 - 3 times the cost of a conventional air furnace system. However i belive the comfort value is worth the extra cost.
if you do a combination Hydronic - air system the cost will be about the same as conventional. In that system you use the boiler to heat the water but then use a heatexchanger and air fan to move the heat around in your building / bus what ever you have. That is what most people do that buy woodboilers, they mount a heatexchanger in to the existing plenum of their hot air furnace and heat that way.
Good luck with designing your system and keep us updated.

[gotmuddy]

if they are so inefficient why are so many sold? Everyone I know that has them says they work great and use LESS wood than a traditional stove. One friend has 4 chicken houses and he heats them with outdoor furnaces

[swinada]

if they are so inefficient why are so many sold? Everyone I know that has them says they work great and use LESS wood than a traditional stove. One friend has 4 chicken houses and he heats them with outdoor furnaces

nah they dont use less wood then traditional, but you have the option of heating more then one building with the same stove. Where otherwise people probably would not heat the shop or greenhouse or hottub they will with one of those boilers and hence might use less energy then with the traditional way. But if you compare of what you burned with a inside woodstove and then switch to an outdoor you will be using more wood. but it will take you less time to get it since you dont have to split anymore.

[gotmuddy]

It was just an idea.

[swinada]

its a good idea if your planing on fulltime living in your bus, i would do it. but just for camping, nah north worth the effort.
The quickest way to hook something up would be, build your boiler and then use regular heaterhose and hook them up to one of your existing onboard heaters that are already in the bus. What i have seen done also befor is the guy just hooked up a radiator out of a pickup had the water circulate through there and put a regular houshold fan 110v behind it. worked pretty well to heat his little ca. 800sqft house

[Sojakai]

I was reading a site where a guy did the same thing for AC in his Skoolie/bus. Only difference was that he had a heat exchanger on the roof and a pump to get the water from the inside radiator to the heat exchanger.

I wonder if you could put a valve or two in there to switch it from the AC described to just the inside radiator hooked to the engine. Heating and Cooling in one...

Probably a dumb idea, but its something...