this post was submitted on 19 May 2026
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The primary issue is that there's a limit to how much energy you can get out based on the difference in temperature between the cold fluid (liquid or gas) and the hot fluid. With data centres it's maybe 20°C? Based on that assumption and the Carnot Theorem you get a maximum work extraction efficiency of about 6-7%.
Unfortunately, in the data centres they obey the laws of thermodynamics.
It would work better in places that get colder, but unfortunately places like that don't tend to have as much available electricity (or infrastructure).
An aside:
We are starting to run up against fundamental laws of how much energy is required to do a certain amount of computation. i.e. In order to do a computation that moves a system from a state X to another state Y, there is a minimum amount of entropy change. That entropy change requires a certain amount of energy based on thermodynamics, known as the Landauer Limit.We were already only about a billion times less efficient than the limit in 2012. I would wager we've improved computation per watt by 1-2 orders of magnitude since then. Which means we might only be 10^7^ or so off of the limit. That sounds like a lot, but when you think about how fast we're improving...
Yeah, this is fundamental; if you use a thousand joules of energy to do work (of any kind) you will ultimately end up producing a thousand joules of waste heat. The only choice one has in the matter is where that heat goes.
This is a major reason why I get annoyed at the people pooh-poohing space-based data centers. It literally puts the waste heat outside the environment. It should be everything that data center opponents say they want.
So that's where they put the front after it fell off? Space?
I read an article a month or two ago that explained without an atmosphere to carry away the heat, the chips would just super-heat and melt.
That article was incorrect, then. There are many satellites already in orbit that have computers in them - basically all of them do, nowadays - and cooling them is a well understood engineering problem.
The satellite computers don't perform as much work, produce as much heat, or are as densely placed as those in the data centers.
So don't pack them as densely as Earth-based data centers are packed.
In another comment in this thread I posted a link to a youtube video by Scott Manley explaining the math and engineering behind cooling computer hardware in space, it's actually pretty straightforward.
How was it incorrect? How can you transfer heat away from the electronics into another medium when there is no other medium because it's in space?
Same way radiation heat works from the sun.
Space-based data centers are wildly impractical to bordering on not physically possible. The largest feature on the ISS, which you can resolve from earth with a pair of binoculars, is the radiators, and it generates 70 kW. Large data centers use >100MW of electricity. You'd be looking at large fractions of a square mile of just radiators.
The radiator panels on the ISS are 2,500 square meters in area. The radiator panels are 645 square meters.
Most of the proposals for space-based data centers have ended up focusing on plans to place thousands of individual satellites into orbit, not just one big space station with everything packed inside it. Scott Manley recently did an analysis of the cooling requirements, he worked through all the numbers and explained how it works, and there really doesn't seem to be a problem here.