Air control on an OWB

[loadthestove]

I.m in the process of building my second OWB.hopefully I can correct the mistakes I made on the first one .Second stove will hold around 225 gallons of water.I'm planning on using a natural draft for temperature control.I want to use an aqua-stat to control my water temp .
on my first stove I used a(Manual) air control similar to the one on my free standing wood burner,it works but requires a lot of monitoring to maintain a consistent water temperature.
Here is my question,can I use an aqua-stat and an actuator to open and close the draft door for my temperature control? IF so what type actuator do i need?If i remember correctly combustioneer used a similar design with a bi-metal spring to control stove temperatures.
Also I need your input on this idea,I'm using about five foot of a 500 gallon propane tank.I plan to stand it on its end and place a divider in it.the top half will be for water and the lower part will be for the firebox.I also plan on using an external(well casing) pipe for the stack(coming out the side of fire box ).
As you all know .a typical OWB is basically a barrel inside a barrel.when you have them burning all that is heating the water is the top half of the inner barrel.In my design I will have thirty six inches of hot surface heating the water
My though is by doing it this way I will have a greater heat transfer area ,and it should lower my creosote build up as only the top of my firebox will be underwater and therefore the pipes will maintain a higher temp and stop or cut down the build up.
The stove is housed in a12 x12 well insulated block building so heat loss around the pipe is not a big issue
Sorry for being so long but I guess I'm trying to build a better (Mousetrap)Stove
Any input or ideas will be greatly appreciated.

 

[projectsho89]

The simplest draft control is to use a water heater thermostat (clamped against the tank) as an aquastat that energizes a solenoid that pulls the draft door open and, when released, allows the door to close by either gravity or via a spring.

 

[mtfallsmikey]

The simplest draft control is to use a water heater thermostat (clamped against the tank) as an aquastat that energizes a solenoid that pulls the draft door open and, when released, allows the door to close by either gravity or via a spring.

That's an ok way to do it, but HWH t-stats aren't that accurate. The aquastat/solenoid deal would be cool....check out a solenoid like the ones CB uses, or, if you check around, you might find a HVAC damper actuator motor, which has limit switches built in, and should be reversible.

 

[trialanderror]

i used a small inducer fan from a typical common hvac furnace, as so it's easy to find and cheap to replace (acutally i work at an apartment complex, and i have aquired handfuls of furnace parts, i built my eletronic controls with 24v transformer, 60amp (so i know it'll last) contact relay for my blower fan & solenoid, on/off switch to kill the draft fan/damper when loading, etc etc)

then i went to the junkyard and bought a cheap $10 chevy s10 throttle body, didn some fab work, a bit of welding, and used a different spring, with the solenoid, i now had a functioning airtight draft that bolts directly to the inducer fans housing, which poked nicely into the 2" axle shaft that works and weasels it's way though the water jacket, into bottom back of the stove, under the bed of coals (no worrying about wood jamming the draft open, buddy had that happen a few times with his CB..)

Then i setup a dwyer controller (donated to me from a AS fan, you know who you are!) to use the 24v-lowamp instead of the direct, high amp draw of 120v to control the fan&draft as needed. Best of both worlds in my opinion. It's very ugly, but it works. I have only a few hundred dollars into my setup, and it functions as well as my buddies $10,000 CB, maybe better in some aspects.... (need to exclude the logstor, as that's required no matter what you do)


the best part i think is the throtle body has various holes for vacuum ports and such, i have those stuffed shut at the moment, asi t's colder and calling for heat every few hours, but during the summer i had problems of the fire going out because of the many many hours before needing to call for heat (mayby it's because there's 18" of insulation on all sides and bottom, and 40" on top? ) so i unplugged a hole about the size of a pen, and that gave enough air from natural draft to keep coals hot enough for the next call for burn to take off...

not sure how many btu it's rated for, was 500k, but i put on a bigger blower fan...now the inside baffels glow cherry red sometimes.... o.0

I did have problems of heat pushing up through the chimney, so to compensate for that i took some plenum tape and muffeled off 3/4 or so of the throttle body intake, so it sucks enough air to just 'fluff' the coals you could say....

have fun building. hope my ideas will make your building easier, or maybe point out something better so i can change my setup. that's the best in sharing information.

 

[mtfallsmikey]

i used a small inducer fan from a typical common hvac furnace, as so it's easy to find and cheap to replace (acutally i work at an apartment complex, and i have aquired handfuls of furnace parts, i built my eletronic controls with 24v transformer, 60amp (so i know it'll last) contact relay for my blower fan & solenoid, on/off switch to kill the draft fan/damper when loading, etc etc)

then i went to the junkyard and bought a cheap $10 chevy s10 throttle body, didn some fab work, a bit of welding, and used a different spring, with the solenoid, i now had a functioning airtight draft that bolts directly to the inducer fans housing, which poked nicely into the 2" axle shaft that works and weasels it's way though the water jacket, into bottom back of the stove, under the bed of coals (no worrying about wood jamming the draft open, buddy had that happen a few times with his CB..)

Then i setup a dwyer controller (donated to me from a AS fan, you know who you are!) to use the 24v-lowamp instead of the direct, high amp draw of 120v to control the fan&draft as needed. Best of both worlds in my opinion. It's very ugly, but it works. I have only a few hundred dollars into my setup, and it functions as well as my buddies $10,000 CB, maybe better in some aspects.... (need to exclude the logstor, as that's required no matter what you do)


the best part i think is the throtle body has various holes for vacuum ports and such, i have those stuffed shut at the moment, asi t's colder and calling for heat every few hours, but during the summer i had problems of the fire going out because of the many many hours before needing to call for heat (mayby it's because there's 18" of insulation on all sides and bottom, and 40" on top? ) so i unplugged a hole about the size of a pen, and that gave enough air from natural draft to keep coals hot enough for the next call for burn to take off...

not sure how many btu it's rated for, was 500k, but i put on a bigger blower fan...now the inside baffels glow cherry red sometimes.... o.0

I did have problems of heat pushing up through the chimney, so to compensate for that i took some plenum tape and muffeled off 3/4 or so of the throttle body intake, so it sucks enough air to just 'fluff' the coals you could say....

have fun building. hope my ideas will make your building easier, or maybe point out something better so i can change my setup. that's the best in sharing information.

Awesome!!..I like others who do science projects like yours...rep for ye!

 

[loadthestove]

great input guys,Never though of using a throttle body.was considering using a power door lock motor to open and shut damper.

NASA has nothing on the folks here.LOL