Holzvergaser, German tech

I am loathe to start a new thread for no particular reason but a German friend of mine pointed out very interesting news from a German developer. Bernard Werner. He claims that he is producing 1 kw. from .6 kilos of wood. I looked in the library here and didn’t find a mention. If you search google and google images on… holzvergaser + patents…
you find quite a bit of interesting info. This patenf by Ulrich Finger cites the patent by Bernard Werner. EP0839893 A1
I haven’t had time to follow up on all this yet. My friend Wolfgang says that the Werner devices are very “big” in Canada. He has spoken with Herr Werner on a few occasions.
I’m posting this to expose interesting technology.


I am going to be a jerk, please bear with me.

The units are meaningless. That is like saying I got 450hp from a quart of gasoline. OK…fine, but for how long? We(I) need to compare a “chunk” of energy output like a kWhr, Joule, or ft-lb to a “chunk” of fuel like a quart of gasoline or a kg of wood.

If he is claiming 1kWhr of electricity from .6kg of wood it will never happen based on the first law of thermodynamics. Check out:

If he is claiming heat and electric recovery that is possible but it is unimpressive.


P.S. Numbers are such a joy killer.


The main question is is he producing 1 kw of electricity on .6 kg of wood or is he combining his heat recovery numbers into the total as many chp people seem to do. In electricity that would almost impossible.

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I doubt it, you can get 80% recovery of just heat, which makes it around 2.6kwh.
Using Stephen’s math…
1lb = 2.52 kg, but he is using 1.32lbs.
3.32kwh is available.
or using his efficiencies:
3.32×.7×.7×.2 = .32kwhr.

In reality the single-stage NG fired engines at “peaker plants” have a conversion efficiency of around 40% so that includes the genhead number as well.
3.32. * .7 * .4 == .93kw/hr, add a slight .05 for gasifier efficiency and you are at about 1kwh.(technically .98kwh)

The units are meaningless because I forgot to write, “KWH”. I need to be more careful. I want to look over his designs and see if there are any ideas that I can adopt. Unfortunately, I don’t read German.

Can Google translate help?

Hey William Google traslate does a very good job on German language woodgas info. Couple of words to watch out for are German roost will translate as “rust” but is actually a grate. And another that slips my mine for a moment. Ahh. Yes. German capitalized four letter acronyms describing 40’s era solid fuel hearth types will not translate. They mean variously starved air gaseous fuel producing hearths. This was to distinguish them back in the age of external combustion from the far more prevalent full air allowed combustion hearths for strickly heat power.

In my opinion any fuels to energy equivalencies are only valid if they step out from too easy, unrealistic steady state conditions.
Two examples of real world:
#1 My wife with her old school cough-choke-spit-stall carburetor absolutely EFI unnecessary 5-8 minute morning sitting warm-ups get’s ZERO credit for miles per gallon of the fuel she uses. ME, starting up for her, just-in-time and pushing her to immediately driving for one month jumped her cumulative fuel economy up from 20 mpg to 21 mpg over that 30 day average.

#2 I’ve had different 5 hp rated engines used and fuel accounted for. The 950 pound cast iron slow speed one had the best rated grams fuel per Hp/h. Yeah. Right. ONLY after the 45 minutes it took to warm up all of that mass to stabilized operating temp!! Then the fuel energy loss every time shut off lost going cold again. For 2-4 hour batch burst of power genration twice a day a 200 pound medium speed engine engine with a higher grams per hp/h loaded only to 5 hp could beat the overall fuel use. And 15 minutes at a time use on my 75 pound high speed gasoline sawmill engine was far more overall fuel $'s use efficient than starting, heating up to stability either one of cast iron beasts.

Beware - the steady state numers. They will lie to you in the real world usages conditions.

Ouch! Sorry for the bold capitalization. Unintneded. Some kind od four finger typling mistake by myself.

Steve Unruh


Not your fault Steve, the # character means headings in Markdown. To avoid it just add a space before (I fixed it).

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My point was that it is -possible- to get that number without the counting the heat output.

You make valid points.
If we are going to nitpick more, you actually get more BTU by adding a bit of water to bone dry wood.

The whole "big engine" scenario is a very common issue with peaker plants and part of the reason why peak hours are more costly. Because you have to fire them up so far in advance it becomes a best guess scenario as to when it needs to happen and they maybe fired up and never used. And in part it is due to the fact they are less efficient at conversion then the -really- big plants which can get up to like 60% efficiency for NG.

Thus batteries which can react instantly to load spikes would be a big boost in efficiency. It buys that extra time which can open up other options like buying a contract, load dumping, etc. You can also more easily locate them like behind the meter at a manufacturing plant, etc.


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Thanks for the clarification ChrisKY. I was frustrated getting ready to just erase it out.

On WiliamB’s topic try this:
Holzvergaser mit Industriekosfilter searched will get you there also.
in the English translation the word “carburetor” means gasifier.

Steve Unruh