Quote:
Originally Posted by IamIan
It isn't quiet that bad ... especially from a 'energy I pay for' perspective.
From a Energy balance point of view to break even ... I think the current technological lower limit would be around ~138% efficient electrolysis ... and ~276% from what I've seen in things automotive size...
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I think we may be defining "the device" differently. I am referring only to the electrolysis unit itself, which has an electrical input, and and output of H2 (and O2) that represents some fraction of the electrical input energy. (There are "real" H2/O2 combined gas electrolysis units used for jewelry welding:
WAXCO-Oxyhiydro blowtorches . These produce 4 liters per minute with a .95 kw input. The H2 content is 66% of this.) Only the H2 has any fuel value. If you do the math, you find that even these professional units are not especially efficient, producing 1 liter per minute (the standard HHO promoter claim) from about 250 watts (not the 140 watts that is the standard HHO promoters claim.)
The requirement for 500% efficiency from the electrolyser device itself comes from the efficiency with which an engine and alternator produce electricity. The 20% I usually use for the sake of argument is actually high, because engines do not really operate at 25% efficiency, and alternators don't operate at over 75% efficiency. Realistically, engines in non-hybrid cars operate at more like 22%, and alternators are more like 65-70% -- we'll say 67%. So the efficiency from fuel to electricity is 15%. To just get to break even the electrolyser would have to operate at 666% efficiency.
The NASA study often referenced has nothing at all to do with HHO -- the injection amounts are far far higher, and the mixtures are far leaner, but most importantly the H2 comes from a tank.