descent
Contributor
Yes, that's true. Sorry for the cryptic terms. The point I was trying to make was not about stationary power sources.
The CCR diver's breathing loop is cleverly driven by human muscle power, and warmed (even more cleverly) by the warmth of exhaled air as well as the scrubber reaction. Humans also have robust protection against chilly breathing gas built right into their face.
I don't believe the human body can handle cool blood as easily, nor do I think you would want the diver's cardiac muscle tissue powering the entire ECP loop.
How then could we drive a system like the one you describe?
Again, sorry for the jargon.
Before hitting submit, I deleted a bunch of additional details about the Boeing 787 Dreamliner because I assumed that everyone here was already familiar with their unhappy safety record. You saw the shorter version. Perhaps the longer one would have been even less intelligible.
Diving to 1500 fsw on ECP and returning in good health would require a significant energy source. The diver's body needs to be continuously warmed, possibly for hours on end; ditto the saline diluent; the O2 must be preheated before injection; and the apheresis loop itself, which is essentially a huge heat sink, must be kept at blood warmth the entire time.
Power for these environmental needs could come in the traditional way -- down a long, heavy umbilicus from a DC generator on the support vessel -- or via a short umbilicus connected to a large, stationary power brick on the sea floor. Both of those options require some kind of winch or hoist. Both options also rob the diver or his support vessel of a great degree of independent movement, and we want our diver to be an unshackled solo explorer.
My point was that power supplies able to do this kind of work safely are far too heavy for a person to lift, and the portable ones that might work with this design are able to store so much energy that carriers like FedEx and UPS make us package and ship them as if they were explosives. They can (and do) catch fire or explode in storage, in transit or during use.
If a lithium-ion array is too complicated or unsafe for a deep diving application, the only other technology I can think of that would fit the bill would be a radioisotope thermoelectric generator (RTG). The radioactive decay produces continuous heat reliably for many years. They are tough. It is quite a challenge to make one stop working. For underwater use, you could even leave some of the lead shielding off to make the unit lighter, but you would want to put it back on near the surface.
