[Gasification] Underwater gasification?
sam at bristolwireless.net
sam at bristolwireless.net
Wed May 18 15:03:36 CDT 2011
Hi all
I wish to move a 22ft 1 tonne boat using wood power.
I have already considered gasification + combustion, gasification +
stirling engines, even steam power!
My latest thought experiment is gasification + thermo-electric generators.
looking at the products of tegpower.com it seems like this may be
viable, if somewhat expensive (£4k)
To move the boat at around three knots will take an estimated 40 -50
amps http://www.floveroutboard.co.uk/outboards.html
Which will require approximately 50 of the TEGP15 thermo electric
panels http://www.tegpower.com/products.html. I then need to keep one
side of the panel at 20C (or lower) and the other at 260C. (but no
higher than 325C)
Initially I considered doing this with an active water pump driven
cooling system, which would be fine, however if the pump/wiring fails
or gets blocked the considerable investment in TEG panels melts before
your eyes.
So I figured given all the water around the boat it might be better to
run a passive cooling system, and actively pump the air for the
gasifier. That way if something breaks it just cools down and stops
working.
Which leads me to the challenge of gasification underwater..
I have taken as a benchmark the mega fireplace gasifer
http://www.woodgas-stove.com/how_to_use_woodgas_stoves.php which puts
out 55,000 btu/hr which on paper is enough power.
So I am thinking about taking take a 14inch x 6ft diameter steel pipe
with a sealed end and sticking a woodgas fireplace in it. Then feeding
a air supply pipe down to the bottom, and using a fan to force the air
in.
The TEG units will be attached to the inside of the pipe with some
kind of heat conducting cement. The water temperature outside the pipe
(typically 5C - 15C) will provide the passive cooling, and the heat
rising up from the stove will heat the inner panel (maybe!)
I did a bad diagram here: http://i.imgur.com/SYpu2.jpg
I realise the engineering challenges of this are not trivial..
* Are forced updraft gasifiers harder to make/ less efficient on this scale?
* What would be a good guesstimate for the temperature at the bottom
TEG? The top TEG? Above 325C?
The next step is to buy a the pipe and woodgas fireplace and do some
real world tests. Is it worth me taking that next step? Do you see
insurmountable problems?
Thanks
Sam
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