# Wood gas and power conversions

So now that I know I will be able to start my gasifier up and run my lawn mower, running implements have been on my mind. My problem is all of this is new to me. My past experience is to buy gas for the right engine.
I have never thought of wood as energy to shaft power. I just learned it takes 30,533 btu’s to acquire 12hp. I also learned there is approximately 6500-6800 btu’s per pound of wood depending on moisture and other variables. I may be a little slow, but things are starting to click. It really shows me how much I have taken for granted when I jump in my truck, turn the key on and drive or turn the lights and tv on and they work and I just pay the bill at the end of the month.
I’m sure most of you know already, but for some of us that don’t, here are a couple of resources to refer back to if needed in the future. I searched this site tonight to find something similar and came up empty handed. I’m sure it must have been covered before, but in case it hasn’t, here it is. Feel free to add other information like charts and conversions that may help me. I am a visual learner. Now it’s just a matter of putting the puzzle pieces together. Any input will be appreciated.

https://chimneysweeponline.com/howood.htm

http://www.unit-conversion.info/power.html

Good stuff there, professor Bill!

Good stuff BillS.
Let me modify this a bit from real world working woodgas to engine power making.
Figure easy at 5000 BTU’s effective for every actual pound of wood fuel that will be needed/used. SI folks just use calories/joules and kilogram weights.
This will account for wood fuel used to get a system from cold, up to a heated operating temperature. And the heat enrngy loss at shut down when the system is into heated energy shed out cooling producing NO POWER.
As I tell my ‘old-carburetor-schooled’ Wife, “Your car is getting zero miles per gallon out there warming up your seat for you!” (she even has electric seat, mirrors and lower windshield heaters!)
Surprise. Surprise. This year with me going out and starting it up for her just-in-time every morning she has now jumped from a previous cumulative indicated 19.8 MPG last year to a now indicated 21.1 MPG overall. Same tires. Same tire pressure. Now 175K versus 145K so we can rule out engine loosening up.

BillS for BTU’s per gallon of gasoline you can find all over the board from 115,000 to ~128,000 depending on seasonal variation mixes. Ethanol’s pulls down the BTU’s.
Easy. Just use 100,000 BTU’s per US gallon of gasoline.
So, yes a very realistic take at least 20 pounds of sub 20% moisture wood to replace every gallon of gasoline that you would have used.
Propane use 70,000 BTU’s per bought/delivered gallon. I forget the pound weight per gallon. This varies too along with BTU’s depending on the propane “mix”. Three different spec grades I am told.

IC Engine fuel use comsuptions are only ever manufacturer quoted in gallons/liters/grams per hour ON FULLY WARMED UP STABILIZED ENGINES.
A light weight little air cooled will have much less warming up non-power fuel use than a big heavy cast iron water cooled engine. The same spread in shut off cooling down NO POWER energy loss.
Every engine will have a non-useable power idle base fuel consumption that MUST BE FUEL cost paid for before any external power can be taken off.
As an unloaded IC Engine RPM rises this non-productive base energy needed to fuel supply will rise also with increased cooling system and oil pumping needs. Friction increase is minor. Internal and even external “windage” power needs DO go up dramatically.

Systems warming up to operations and base power needs have to be energy paid for up front before you can generate a single kilowatt of ANY EXTERNAL USEABE POWER.

And I hate and refuse to use killowatts for any use but electrical power!! My old schooling.
The math simplicitiers/equivalence’ers/armchair’s then have to do things out long hand to then at least get hopefully ballpark close to a real world reality situation.

These are the realities that hold always:
If you only need dog sled, goat cart power DO NOT GET AND FEED A BIG HORSE.
And a big cow/ox ruminate with three stomachs is 3X as feed efficient as that horse. Slow though. Very slow.
A goat is a multiple stomach ruminate too, and just like the cow/ox able to eat a lot rougher fuel with much lower feed costs than a meat eating dog.

What’s this got to do with woodgas??
IC engines vary much also in their fuels conversions efficiencies and fuels range usability.
Killowatt maths users; and heats energy equivalencie’ers are some of the most blinded; and self-deluded folk you ever run into when the rubber meets the road, and the drive belt rubber meets the drive pulleys.

Regards
Steve Unruh