posted on Nov, 25 2005 @ 04:52 AM
Originally posted by Clownface
"Days on end"? That's not really impressive if it's supposed to be a ultra modern system.. Our swedish subs (diesel) with Stirling systems can
manage weeks without surfacing.
AIP isnt AIP
. There are many different approaches to the problem of submerged conventional propulsion and the work on it began in the 30s in
Germany. The Stirling systems are technically inferior to the german system (then again, swedish Kockum who builds the Gotland AIP system belongs to
german HDW...). They are more complicated in build than the fuel cells and require more sorts of fuel (Oxygen, diesel, Helium, Nitrogen) and they
still operate via combustion, creating noise and heat (though less than a conventional CCD - closed cycle diesel engine). Almost all energy that
cannot be converted to electrical energy in this process is lost.
The fuel cell system however directly produces energy by a catalytic reaction, You have greatly reduced loss here and once the system works it is less
prone to failing than the combustion AIP systems (no moving parts, rather simple build, no heat and vibration that could produce material stress, it
consists of several fuel cells and even if one or more break, the rest continues to work with the same performance). You also do not have to
post-process the exhaust of the fuel cell, because the only product is pure water which can be released directly outboards or even be used for the
ship, for example the showers and toilets.
A clear sign for the superiourity is also the greatly increased energy output: while the Gotlands two Stirling systems generate 75kW each, the two
fuel cells in the new Dolphins will generate about 100-120kW. The Stirling system is said to last up to two weeks submerged at 5 knots while the fuel
cell is said to be capable of three weeks at 8 knots - although both numbers are only theoretical and greatly influenced by the outside factors. More
notably the fuel cell can generate a peak power output by itself. The Gotlands have to rely on their AIP charged batteries.
There is only one downfall of the fuel cell system, and that is the rather dangerous refilling of the potentially explosive H². Once the tanks are
filled this is no problem, they are below the waterline and the H² immediately dissolves in the seawater in case of a leakage.
[edit on 25/11/2005 by Lonestar24]