From the Wikipedia entry on Revelation Space universe technology:
"Cryo-arithmetic engines are a specific class of quantum computer discovered by the Conjoiners. When certain algorithms are executed on processors of this architecture, it leads to a local violation of the Second law of thermodynamics: the computer gets colder instead of hotter. Consequently, cryo-arithmetic engines have massive industrial (as opposed to computational) ramifications for Conjoiner manufacturing; such engines abound in Conjoiner asteroid factories, where their calculations can drain away the heat of starship construction."
I was tickled to note that a number of commentators have drawn a parallel between my made-up pseudo-science and this recent breakthrough:
In the interests of fairness, though, I'd have to point to Greg Bear's excellent novella "Heads" as an earlier example of SF dealing with computation and weird thermodynamics.