Thoughts on OWB Optimization??

[NC4AB]

I have just finished the install of my Hardy H2 and wondered if anyone had any suggestions on how to optimize the burn. I currently have a Ranco two stage aquastat with independent control of the damper open / close and fan on / off. In the future I plan adding a PLC (Programmable Logic Controller) to control the fan, the fan speed and the damper independently, and was wondering:

Is natural draft more or less efficient than using the forced draft fan?
With natural draft I get long slow burns with a continuous light smoke plume with a low exhaust stack temperature, versus with the forced draft fan running I get a short, cleaner burns with a much higher stack discharge temperature.

I am currently setup to log data 24x7 on water temp, damper open / closed and fan on / off status and plan on adding a stack exhaust temperature sensor when I can scrounge up an RTD.

Any thoughts?

 

[fletcher0780]

I think your efficiency questions depends on fuel quality. The clean burning indoor wood boiler types use short hot burns and store the energy for longer periods. I'm guessing they either need to be filled a few times per day, or have large water storage tanks incorporated to help store the energy. The forced air is very nice for damp, green, or poor quality wood and quick recovery. If your adding a control system maybe you could make it so your system is selectable depending on your fuel type? Have you ever checked out the web energy logger? I stumbled across it when I did my geo AC system http://www.welserver.com/

 

[ghitch75]

reduce the flue to 4"..you will see shorter burn times and less wood usages...

 

[itn]

i have thought that with my cb it would be nice to have a forced draft fan that would start for about 30 sec. when it first called for heat and then shut off and let the natural draft finish it out.

 

[Butch(OH)]

I am also going to play around with my Woodmaster 4400 draft this winter. I have a feeling that the draft is set up to burn anything (which it will) and thus is pretty strong for the dry split wood I burn. Dealer says it has been tried and all it does is make it smoke more but I am the "show me" type. I hate to get the thing too complicated with gizmos but thought about a timer on the blower to shut it down after a short time and letting natural draft do it's thing. I have also thought about simply restricting it at the intake, or exhaust or even unplugging the draft fan completely to see what happens to my wood consumption. Smoke is important as I do have three, non complaining by the way, neighbors. I am not dissatisfied with wood consumption now as compared to the two wood stoves it replaced but just want to play with it some.

 

[jeeptj19992001]

I have just finished the install of my Hardy H2 and wondered if anyone had any suggestions on how to optimize the burn. I currently have a Ranco two stage aquastat with independent control of the damper open / close and fan on / off. In the future I plan adding a PLC (Programmable Logic Controller) to control the fan, the fan speed and the damper independently, and was wondering:

Is natural draft more or less efficient than using the forced draft fan?
With natural draft I get long slow burns with a continuous light smoke plume with a low exhaust stack temperature, versus with the forced draft fan running I get a short, cleaner burns with a much higher stack discharge temperature.

I am currently setup to log data 24x7 on water temp, damper open / closed and fan on / off status and plan on adding a stack exhaust temperature sensor when I can scrounge up an RTD.

Any thoughts?

wow you got tooo much time on your hands, i just load mine up twice a day.
and let the thermostats do the rest.

 

[cleanburn]

Forced draft is the way to go in my opinion. If you are putting too much heat out your stack you need more heat exchanger area in your stack then...

 

[ngzcaz]

Its a funny thing, we all want to optimize the burn but dont want creosote or smoke coming down at us. Hotter temps out the chimney means less creosote and the smoke will rise quicker but probably more wood consumption. Cooler stacks equals creosote and smoke that may dip a bit depending on the conditions.
Like the man says, ya pays yer money and ya takes your choices.

 

[mtfallsmikey]

More complexity...more chances for problems!

Like Dad used to say to some customers who were confused as to why something broke down....

:deadhorse:
"Anything made by man is subject to mechanical failure"

 

[HUSKYMAN]

I am also going to play around with my Woodmaster 4400 draft this winter. I have a feeling that the draft is set up to burn anything (which it will) and thus is pretty strong for the dry split wood I burn. Dealer says it has been tried and all it does is make it smoke more but I am the "show me" type. I hate to get the thing too complicated with gizmos but thought about a timer on the blower to shut it down after a short time and letting natural draft do it's thing. I have also thought about simply restricting it at the intake, or exhaust or even unplugging the draft fan completely to see what happens to my wood consumption. Smoke is important as I do have three, non complaining by the way, neighbors. I am not dissatisfied with wood consumption now as compared to the two wood stoves it replaced but just want to play with it some.

Seems to me this might save a little electricity, but I dont see it saving any wood. It takes a certain number of btu's to heat the water to heat the house, no matter what type of draft you use. However it will be interesting if you can prove otherwise. Having a forced draft means less smoke at cycle startup and faster cycle times, but I think wood usage stays mostly the same