What's the most efficient way to turn wood into electricity?

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Hobbit   100 W

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What's the most efficient way to turn wood into electricity?

Post by Hobbit » Mar 22 2013 11:20pm

I have loads of trees on my property, so a limitless, endlessly replicating supply of firewood. I'm thinking about maybe a steam powered generator. Now, wood into heat, heat into steam, steam into kinetic energy to drive something that electrikety comes out of, the "losses" involved are going to be pretty huge but i'm still trying to get from burning "free" wood to charging my bike. Kinda choosing just how much greenhouse gas i'm producing, switching from government run coal to do it yerself..... Right now i'm just thinking it but I thought i'd bounce it offa you guys and see what's where?

Someone somewhere musta thought of something like this ( and then maybe just went out and set up solar for heaps cheaper :mrgreen: )
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Re: What's the most efficient way to turn wood into electric

Post by SamTexas » Mar 22 2013 11:50pm

Hobbit wrote:Now, wood into heat, heat into steam, steam into kinetic energy to drive something that electrikety comes out of, the "losses" involved are going to be pretty huge ...
Is there another way? I'd like to know too.

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Re: What's the most efficient way to turn wood into electric

Post by amberwolf » Mar 23 2013 1:07am

Could you process wood into alcohol and burn it, and then also burn the remains?

There is also wood gasifier stuff, might help with the efficiency of the process.

But I can't think of a way to directly turn the wood into electrical energy--the fire, steam, kinetic, electric is the only one I know has been developed and works.

It is possible to convert heat directly into electricity using Peltiers, but it is probably even less efficient than the other cycle.

Can also be done with the effect used on thermocouples, but again, efficiency is probably less tahn the other cycle.

I guess you could stick piezos and solar panels and thermocouples in the burner area, to absorb some of the otherwise wasted heat energy that doesn't make it into the water to turn to steam, and onto the "cold" end of the steam condenser to reclaim some of the other energy, but it's going to add to the cost of the system (probably a lot).

Better insulation, and additional heat collection stages for the exhaust air, to put more heat into the steam boiler, would possibly dramatically increase overall efficiency of that stage, but I don't know if it would be worth the expense of it.

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Re: What's the most efficient way to turn wood into electric

Post by Hobbit » Mar 23 2013 1:27am

The video below is something like what i'm thinking of using for the "hottie,hottie,boillie,boillie" part....

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Re: What's the most efficient way to turn wood into electric

Post by liveforphysics » Mar 23 2013 2:00am

Im pretty sure the answer to the efficiency at turning wood to electricity would involve drying it very thoroughly and holding a silk handkerchief up to it while its turning. :-)

This would mostly be wasting the energy in heat from friction though, but it would let you directly rub off electrons and store the charge in the non-conducting surfaces.

If your aim is purely efficiency, and you're just looking to convert potential energy stored in the wood, I would get a CISRO motor, put a good string spindle/pulley on its shaft, mount on a tall pole just above your tallest tree, tie the string to the top of the tree and cut that mass of the tree off that lets it fall in a way that spins the motor in its 97% efficiency range. I could easily be convinced a total kinetic energy conversion to electricity could exceed 90% including all aero drag loss on the branch and string friction on the shaft spindle unwinding etc.

But even if you had a hundred metric tons of tree parts to each drop 50meters, you still have a pitiful amount of energy, though you did generate it extremely efficiently. :-)



I personally think rather than building something to burn the wood and drive a Stirling engine from the temp difference between the in a wood fire side and the massive heatsink side (which would work), you could make a parabolic trough design solar collector and generate electricity without burning anything, or needing to stock it with wood or clean out ashes or light it etc, and you could make it as powerful as you were willing to give it space for that gets hit by sunlight. :-)
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Re: What's the most efficient way to turn wood into electric

Post by dnmun » Mar 23 2013 2:26am

you can log it and convert it to lumber and sell the lumber to buy the electricity. then the trees do not die in vain.

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Re: What's the most efficient way to turn wood into electric

Post by Hobbit » Mar 23 2013 4:12am

ah ha ha, voices of reason give a nudge in the direction of the enlightened and the would-be lumberjack puts his chainsaw idea in the bin. Cheers to the sphere!
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Re: What's the most efficient way to turn wood into electric

Post by dfar » Mar 23 2013 5:49am

Wood gasification

you can convert any ICE to run on wood gas and it is actually 33% more efficient than gasoline (btu to btu).

you can run a car, a truck, a stationary generator to power a genset etc.

I converted my truck 1990 GMC serria 350ci to run on wood, cruise at 90-100km/hr on wood and still can run gas when I want with a flick of a switch if on a pinch.

This is for over 50km distances, I use my electric bike for in town stuff.

In your case same principle can be applied, run a stock genset off a wood gasifer for electricity. for heating look into batch rocket bells, they are a off shoot of the well known rocket stove but without the need to constantly be tending the fire.

here the links

gasifers for trucks and also sections on gensets or running small engines: http://www.driveonwood.com

horizontal feed bell rockets for heating: http://donkey32.proboards.com/index.cgi ... thread=691

http://donkey32.proboards.com/index.cgi ... 511&page=1

I need to resize my pictures and don't have time right now. will when i get a chance

oh and burning wood in an ICE has better emissions than gasoline as well, just pure CO2 and H20
HPIM0760.jpg
this is the gas being burned before it enters the ICE (internal combustion engine) for testing the quality of gas only
HPIM0760.jpg (60.71 KiB) Viewed 6687 times
HPIM0782.jpg
the gasifer system mounted in the truck
HPIM0782.jpg (108.33 KiB) Viewed 6687 times

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Re: What's the most efficient way to turn wood into electric

Post by knighty » Mar 23 2013 6:53am

woodgas as above

or burn it in a stove, with a bunch of tegs fixed to the back of the stove, and water cool the other side
(much simpler this way)


if you want lots of power, then woodgas and a generator is the only way to go tbh

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Re: What's the most efficient way to turn wood into electric

Post by pendragon8000 » Mar 23 2013 7:28am

amazing sugestions there gus.
My first thought was to run a steam turbine like power stations do. they get higher efficiency than ICE generators. On a small scale it may be dificult to do but having less moving parts is good.

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Re: What's the most efficient way to turn wood into electric

Post by rp3 » Mar 23 2013 7:34am

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Re: What's the most efficient way to turn wood into electric

Post by spinningmagnets » Mar 23 2013 10:54am

I don't have any experience with wood gasification, all I know is when you heat up wood, but don't let it combust, it gives off hydrogen, which has a wide flammability range...very easy to get it to burn in any engine it's routed to.

Here's my "go to" website for converting lawn mower engines and car alternators to a 12V generator (google has many more):
http://www.qsl.net/ns8o/Induction_Generator.html

Steam from boiling water can produce high pressures. Still used today. At otherpower.com, they used DIY wind-gens and solar-PV panels, but sometimes the wind and sun are weak, plus they had lots of wood. They found an old steam-set that was lawn art. Steam engines are heavy-duty, so it was not hard to get it running again.
Steam gen from otherpower.com
http://otherpower.com/steamengine.html

Depending on your skill-set and tools, I would prefer building from fairly new scrap, an Organic-Rankine-Cycle (ORC). Think of it as "Freon steam". Can use propane, butane, freon, and toluene as the liquid/gas conversion media. (of course, Butane and propane are flammable). It can be heated from the sun when its out, or fireplace chimney heat when the sun is not.

I love Stirling engines, and yet...they have limits. They are not power-dense, meaning you need a large engine to make small power. That being said, they operate off of a small difference in heat, resulting in a small difference in pressure. They can run off of solar power and air-fan cooling.

Here's my favorite, called a 6-cylinder when searching Google. It actually has 3 power cylinders to be the minimum for self-starting (6 heat exchange cylinders). It's a 3-cyl Gamma. If you took a stepper motor the size of a coffee cup (salvaged from a large office copier or ebay), this could charge a 12V battery to supply cell-phone, laptop, rechargeable flashlight cells, etc. The first 3 minutes are the details of construction, I linked the ten second "money shot" at the end.

http://www.youtube.com/watch?v=lvvyjJ8wz3Y#t=3m50

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Re: What's the most efficient way to turn wood into electric

Post by Lebowski » Mar 23 2013 1:26pm

wood gas, thats how people drove around here in Europe during WW 2 when there was no gasoline...

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Re: What's the most efficient way to turn wood into electric

Post by John in CR » Mar 23 2013 5:14pm

Wood gas and run it at the right times to make best use of the waste heat (hot water for showers or heating the house, or whatever, but don't let that waste heat escape without doing some other useful work), and then you can get far far higher efficiency than anyone simply running any ICE.

OTOH, get in with some kind of coop and don't burn the perfectly fine wood. Instead barter lumber for biodiesel or something else your land can't produce.

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Re: What's the most efficient way to turn wood into electric

Post by Dauntless » Mar 23 2013 8:10pm

At least one thread on the subject here. I guess it never quite fleshed out hooking up a generator or pelltier pump to the process.

http://www.endless-sphere.com/forums/vi ... 41&t=45442

http://generatorsprices.com/tag/gasifier/

http://www.instructables.com/id/Fusion- ... y-Reactor/
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Re: What's the most efficient way to turn wood into electric

Post by t3sla » Mar 24 2013 8:12am

sell it as firewood and buy PV panels?

I've seen firewood for like $20 at the servo, you can have a kW setup in no time :)
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Hobbit   100 W

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Re: What's the most efficient way to turn wood into electric

Post by Hobbit » Mar 27 2013 8:26pm

All of the above....

Sometimes the brilliance of this place blinds me with it's sheer awesomeness!
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Re: What's the most efficient way to turn wood into electric

Post by z50king » Apr 21 2013 6:34pm

Cut only a few trees and use them to hold up pv panels....
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Re: What's the most efficient way to turn wood into electric

Post by dingoEsride » Apr 22 2013 1:13am

spinningmagnets wrote:I love Stirling engines, and yet...they have limits. They are not power-dense, meaning you need a large engine to make small power. That being said, they operate off of a small difference in heat, resulting in a small difference in pressure. They can run off of solar power and air-fan cooling.
Yes, these are so cool just to have one running nearby, would take a long time to charge a battery if it could spin a little generator

http://endless-sphere.com/forums/viewto ... =1&t=47180
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Re: What's the most efficient way to turn wood into electric

Post by Dauntless » Jun 02 2013 12:27am

http://www.instructables.com/id/Convert ... /?ALLSTEPS

It'll run on your gassifier just fine.
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Toorbough ULL-Zeveigh   100 MW

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Re: What's the most efficient way to turn wood into electric

Post by Toorbough ULL-Zeveigh » Jun 02 2013 4:52am

t3sla wrote:sell it as firewood and buy PV panels?
not yet as efficient as stirling, currently@8%.
http://en.wikipedia.org/wiki/Thermophotovoltaic
A prototype TPV hybrid car was even built. The "Viking 29" (TPV) powered automobile, designed and built by the Vehicle Research Institute (VRI) at Western Washington University.

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Re: What's the most efficient way to turn wood into electric

Post by megacycle » Jun 22 2013 8:06am

Check this out in a few years Hobmaster, you could have a shed load of Megawatties or Megajoulies.
http://m.indiatimes.com/technology/scie ... 84509.html
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Re: What's the most efficient way to turn wood into electric

Post by Kurt » Aug 07 2013 6:25am

I think the best way to get maximum KWh return from your timber is. Cut the wood up into small logs. Then split the logs up into sections. Let them dry for 12 - 18 months. Then sell the logs by the ton or trailer load as seasoned & split fire wood.

Use the money earned from the firewood sales to purchase electricity from the grid at 25Cents KWH. It would defiantly give you a lot of KWH from a big endless supply of wood. :D

Kurt

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Re: What's the most efficient way to turn wood into electric

Post by Dauntless » Aug 07 2013 1:46pm

Kurt wrote: Use the money earned from the firewood sales to purchase electricity from the grid at 25Cents KWH. It would defiantly give you a lot of KWH from a big endless supply of wood. :D

Kurt
Well, that's definitely defiant on your part. The very LEAST you could have told him he could buy a solar or wind system with the money.

And if you really could see monthly sales to make payments on the system, this could be the way to go.
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Kurt   10 kW

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Re: What's the most efficient way to turn wood into electric

Post by Kurt » Aug 07 2013 4:25pm

It was kind of a Joke but the sad part is its true. In Australia most of out timber stock is hardwood and has a value of $120 - $200 m2 as fire wood.

so 1m2 of fire wood sold for say $150 will purchase 1500kwh of electricity . It would be very hard to build a device at home that could extract and store 1500kwh of electricity from 1m2 of timber.

Kurt

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