"Set Square" wrote in message ...
N. Thornton wrote:
"David W.E. Roberts" wrote in message


Actually, I'd like to be able to generate *all* my electricity from
gas - not just in an emergency. Bearing in mind that the marginal
cost per kWHr
of
(on peak) electricity is 3.6 times that of gas, I would save on
fuel costs as long as the overall conversion efficiency was more
than about 27.5%

Is isnt, thats the problem. If you want efficiency you need complex
kit. OTOH you can get something to work with about a tenner plus a
ride to the auction. If you have unlimited time, and the expertise to
get old junk running.

What sort of old junk do you have in mind?

Any old internal combustion engine plus a car alternator are the heart
of any homemade genset. Lawnmowers appear ideal but have really quite
short lives, so some old farm junk is a better long term bet if its
salvageable. Mowers are fine if you only going to use them
occasionally, but if you want it running 24/7 a mower engine wont last
long.

For a fiver you wont get a wide choice of engines, basically anything
that has an ignition system still on it and hasnt seized solid should
do. Age immaterial.


On the carb side, the nicest idea I saw was a wood powered set that
had basically no carb at all. IIRC the wood was burnt in a drum with
the air sucked downwards throught it, creating wood gas, this was
bubbled through water to filter it, went through long pipes to cool
it, and fed the engine.

To start it you opened a drum bottom vent flap and lit the fire, and
once it began to take hold crank the IC engine and close the flap.

Water cools the woodgas first, then goes through the cooling jacket,
if the engine has one, then cools the exhaust output with a heat
exchanger. Result: lots of boiling water.

Now you have a wood powered genset with leccy and HW output. Cost to
buy a £10+, cost to run: nothing but time. A fun project if you want
to play.


Regards, NT