[ih] greener underwater?

[touch at strayalpha.com]

Hi, Dave,

(With the caveat that I don’t know how “IH” this is, but there’s no need to be that constrictive)…

> On Sep 2, 2022, at 11:44 AM, Dave Taht via Internet-history <internet-history at elists.isoc.org> wrote:
> 
> This piece on a company attempting to build data centers underwater
> went by today on multiple channels. I can't help but think this idea
> was long ago developed and deployed by certain governments long ago?

“Green” IMO depends on:
	- where the power comes from
	- recyclability of the components (after EOL)

I don’t think it matters all that much where the heat goes TO as much as how MUCH heat goes there…
(Yeah, there are kinder ways of dissipating heat than others, but that’s less “green” than “low environmental impact”, which aren’t always aligned).

> 
> "The viability of underwater datacenters has already been demonstrated
> by Microsoft, which has deployed several over the past decade as part
> of its Project Natick experiment. The most recent was recovered from
> the seabed off the Scottish Orkney islands in 2020, and contained 12
> racks with 864 servers. Unlike the Subsea pods, the Project Natick
> enclosure was filled with nitrogen."
> 
> https://www.theregister.com/2022/09/01/subsea_cloud_underwater_datacenter/
> 
> But:
> 
> "The subsea servers are  immersed in a dielectric coolant, which
> conducts heat but not electricity. "

I recall the Cray 2 “fishtank” pioneering this (AFAIR).

> It does spark a ton of questions, fluid is far less compressible and I
> would think better than nitrogen,

Filling with nitrogen reduces oxidation, but I don’t think helps otherwise.

If the outside pressure is carried into the pods, I would worry about crushing chip enclosures.

> but dragging fiber
> and 1MW of power offshore seems the stuff of science fiction…

Fiber goes transoceanic, so that shouldn’t be a big deal.

And power cables support offshore islands, so depends on how far offshore, but again, this need not be new.

> or
> fantasy... and even cooled to 0C I still imagine moving parts, rather
> than convection is required….

Heat pipes have no moving parts, FWIW… 

Joe