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by steve_barham 4536 days ago
There is a detailed analysis of the feasibility of such systems in general on the following web page:

http://www.nigelhewitt.co.uk/diving/rant/#gills

Quote (following an explanation of the quantity of oxygen in solution in sea water at depth, vs. quantities required to breath, yielding a requirement of 2000L/minute of water to be processed):

"This raises three problems in my mind.

"Firstly is size. If the magic box is a reasonable size, say a volume of working water is the size of my scuba tank it will have 12L of water to work on at any one moment. So 2000L/minute means that the water must be in, processed and out in 12*60/2000 seconds. That's just over one third of a second to complete the whole process.

"Secondly there is the fact that 2000L/minute worries me when I consider that my old 20HP outboard had an 20cm diameter prop on it. To move 2000L/minute it would have to knock the water through at 2000/31.4=63m/s, otherwise 142mph in old numbers. So my second problem is that this is a huge amount of thrust for a diver who does not wish to zoom about like a torpedo and the third problem is that that sort of power isn't going to come from ordinary batteries."

Personally, I read the article as a typical design student 'concept' piece; certainly, if I were a battery manufacturer that had a product 30x more energy dense than the competition, which charged 1000x faster, I would not be looking at the scuba market to make my billions.

1 comments

> So my second problem is that this is a huge amount of thrust for a diver who does not wish to zoom about like a torpedo...

Wait, who said I don't want to zoom about like a torpedo?

I'm kidding, of course. Great link!