Hot air is not the best media to transmit heat. We use a hot water based unit that can be converted to hot air of needed, water being a better transmission media. Also you can place the outdoor unit away from the building,lessening the chance of radiant heat tranfer to cause a fire.
The best thing for bio diesel is that a heat exchanger is easily rigged to heat the oil for processing. I have been using a Mahoning outdoor furnace for years, and have been heating my oil for a few months. questions, please email me. DGF
Location: South Central, PA | Registered: September 12, 2006
This idea of an outside wood stove that heats your house via steam power is quite common. I lived in northwest ontario canada for a couple of years and many people have these type of wood burning stoves. This has a couple of advantages to your indoor stove.
I'm sorry guys and gals I'm totally new to this whole thing. I've seen outdoor furnaces and have been amazed on just how they work. I currently am looking for a parcel of land to move a trailer onto and start building around that...anyway, I would be very interested in learning all I can about this.
Is there a site or current plan to build one of these? I think the tank building wouldn't be to difficult but how to move the water, how far away to have the entire system and how to keep it safe. Believe me I hate winter and I'm not about to pay NYSEG a million dollars a year to stay warm that's why I'm very interested in this..
Location: Elmira, NY | Registered: February 25, 2007
there is a spring by my house that flows around 40 gallon per minute I use it to super power a heat pump that I built from old hotel ac units that I got for free. I also have a creek as was going to do a micro hydro project but got scared off by all of the epa stuff when messing in the creek even though we own almost half a mile of it and I would only be running a pipe from one end to the other.
If you heat a large amount of water or other liquid the temps will stay fairly constant. If you heat a small amount in tubing then you have a risk of boiling. Every time the wind changes speed the draft would change and then the fire would flare up making the water in the tubes boil instantly. A large tank will hold the temp for a long time. Build a small fire hot for a short time before you leave for work and let it go out. The water will circulate heating the house until you return to make another fire in the evening.
Since you already have the heat pump, why not build an enclosure like a small yard barn over it and install a SMALL radiant wood stove? No valves, no plumbing, no leaks, no fans needed. You would only have the raise the temp a small mount to make the heat pump work. If you built the shed out of dry stack cement block and put insulation on the outside the cement would hold heat and you may only have to built one or two fires a day.
You'll never go wrong by doing right.
Who do you call when the lawmakers ignore the law?
Location: Belle Plaine Iowa | Registered: November 06, 2006
I built a few out door wood boilers.. and mine work quite nice if I so so myself, very efficient, when you build your stove build it with reburn system 1 estimate mine to be about as energy efficient as wood pellet about 85% - 90%. which is done very simply, basically when you build the fire box you build a portion of the flue into the fire box. by this i mean you cut the hole in the top of your fire box near the front of fire box. then on the top inside of the box you weld a second chamber that runs along the top of the box ( from side to side about 4 inch gap ) also have this continue about 2/3 of the way down the back fire box. what this does is create a reburn chamber here the gases get superheated and burn very clean. now you can do what i did, is either add on a a oil fire furnace gun in a secondary fire box that attached to the same flue system but exhaust gas from the oil fire comes into the main flue at the back of the wood fire box) basically build one big fire use 4/5 of the box for wood and 1/5 for the oil- this way I have a back up system I can go away for extended periods ,200 gallon has lasted me 3 years so far and counting basically when the water drops below 40Cit kicks in) if you want straight wood then create a another gap at the bottom of the fire box that is about 1 inch gap that runs along the entire bottom ( side to side and 1/3 up the back) now your finished the fire box just build your water jacket around it estimate it to hold about 45- 60 gallons of water.
how it works: basically you burn with very little front incoming air which creates alot of wood gas as it being drawn up the flue it pulls in fresh air at the back, just at the internal flue this cause the wood gas to ignite and burn cleanly.
so the whole process broken down ( i burn green or dry no creosote build up) once you get small amount burning about 1/5 of a full fire box, you fill up the fire box with your wood green or dry then close your front damper so very very little oxygen gets to wood in the first stage of the burn it creates mostly wood gas that is burnt in the secondary chamber burn, as it burns it turns a majority of the wood into charcoal then once this begins to burn the fire becomes very hot the hardest thing to do on this stove is to get control air gaps just right and the air tight seals. then you do not need to touch it again. the thing is as the temperature gets colder the density of air increases so there no need to increase the air damper. the only other thing that is very important is it to place an automatic flue damper that is about 1 foot above the stove. you need this so on windy days your wood burn will not increase to dramatically. with this wood stove I heat my house with 3- 5 cords of wood ( i burn almost only all green because otherwise it just too hot) and my winters are long and hard 6 months long and at least 10 - 20 days of - 40C
my my getting a lot of pm on my stove design. it a very simple design.. also what is important is how you radiate the heat off, radiator style is the best be it normal rad or in floor radiation. and a slow flow pump such as taco 003 b4 . here a basic plan of my stove..This message has been edited. Last edited by: Shaun,
none: I built with a 3'x4' firebox and mounted a 100 lb propane tank for the water storage/heat exchanger. I put four 3" pipes lengthwise thru the tank that almost doubles the heat exchanger surface area.one end of tank extends thru the back of the fire box about 1", 4 3/4" pipes come out the top the first pipe was 20" long and goes thru to the bottom of the tank for cold water return.[tank is horizontal] second pipe is for temp pres guage and pres relief valve. third is for expansion tank and 4th is for hot water out.3,4,& 5, were 8" long and just went thru the top of the tank. the hot water out is placed at the far end of the tank so the hot gases will be exiting the stove just after passing that pipe so as to have covered all the surface area possible before going out the chimney.It is plumbed thru the wall to a heat coil with a fan mounted in the duct work of the old main furnace, wich is now the backup furnace. the house is almost 5000 sq ft converted old church. fuel is lump coal, wood, and sometimes a turk burner. firebox grate is made from 1-1/4" schedule 80 pipe that has 1/8" holes drilled in it and a variable speed blower hooked to it for combustion air.Large door to fuel it small door above that to access tubes to brush them and a small clean out door on the chimnet box. Holds 19 gals of water with heat coil. Tank is about 2" below the top of the stove to allow heat to completly surrond it before thru the 4 tubes [3"x 42"] and out chimney. Fire bricked inside. Looks like a 4' tall dog house. approx 375.00 in materials.
antifuel1 that what I started to do this year i bought a few evacuated solar water heaters a couple weeks ago. they work well. one heat 15 gallons of water from 45F to 190 f in about 4- hours of good sunshine... on a - 15 day.. the only thing I do not have cistern and I did not want that volume of water. I am planning to pour cement pads with copper pipe inlayed in them, and I am pouring the forms in such away that they are stackable and they create an air path between the blocks. this way I hoping I can heat these cement blocks to about >180f over the summer and fall months about 10- 20 tons on material.. basically it was going to be small double walled "room" attached to the side on my house. and I just attach the pathway between the slabs to my duct work. and using a slow varible fan to circulate the air constantly I estimate that I should get about -1-2 months heat source out of it with miminal solar input from the collectors. during the low sun period during the winter.. perhap I can get away from my wood boiler all together.. but guess if one has a heat pump you could just add a secondset on copper pipes to draw off or use the existing pipes and just draw of the solar collector lines. at least this way the volume is smaller, you do not have a evaporation problem. and you can reach higher heat storage temaputure
I have never seen a home furnace/boiler it just doesn't get that cold here, however I did work on boilers in the Navy. If I might suggest the firebox should be cast iron or lined with fire brick. Any piping exposed to the flame should be boiler tube, most steels will crack or corrode over time, copper to. A safety valve that is piped to the firebox can help to quench the fire.
Location: Nimbin Australia | Registered: December 04, 2007
In looking at your boiler, i assune the the areas in white are water. how many inches if water are above fire chamber? And where are you taking and returning the water to the water jacket. And I do not see a vent. Are you pressurized?
Originally posted by sash: my my getting a lot of pm on my stove design. it a very simple design.. also what is important is how you radiate the heat off, radiator style is the best be it normal rad or in floor radiation. and a slow flow pump such as taco 003 b4 . here a basic plan of my stove..
I have also been thinking about building an outdoor furnace and have learned a few important tips. First you should make sure you do not seal the system there are several reasons for this. One is that copper pipe is not rated for this kind of pressure you also have to worry about collapsing the pipe. If you get a pinhole leak in the pipe the pressure will force out the water then when the water cools it will create a vacuum which will easily collapse the soft copper pipe. Another thing is that the more water in the system the better it takes an incredible amount of energy to heat water but it also takes a very long time to give up this heat. This means the more water you have the more energy will be stored (less waste better efficiency). I would recommend at least 150 gallons. I would also suggest a battery backup for the circulator pump this way when the power goes out in the middle of the night you will still be able to use all that stored heat.
I have an outdoor boiler project in the works. I've collected two large LP tanks, one 40" diameter and the other 30" diameter. I'll be sizing it to accept logs 4 feet in length and plan to use a forced draft triggered by a temp switch mounted in the water jacket. My calculations show a water capacity of approx 195gallons. This hopefully will heat both of my buildings- a 1300 sq ft. shop and a 3400 square foot home. I plan to have the door hold water as well. The only item I haven;t decided on is if I should have a grate and what it should be made of? And should the draft air be forced under the wood fire or from the door? My undergound tubing is already in and insulated 8ft below surface but is only the common black plastic water line-hopefully it will work at these temps ( 160ish)and also under low (15psi) pressure. Any thoughts? Bob