Comment by roryirvine

It's low-grade heat, so isn't worth much.

If you're going to be doing cogeneration on-site, it can be worth considering a Combined Heating, Cooling, and Power system - but the benefits tend to be fairly marginal.

In the future, there's a possibility of extending the "lights out datacentre" concept, and going fully automated. If you don't need to accommodate humans, you can run much higher temperature gradients.

With a gradient of around 200 K, for instance, you might expect to recover somewhere between 30-35% of your total energy input.

The UK actually ought to be a good choice for an experiment along those lines, given its long history with gas-cooled nuclear systems - sadly, the engineers involved have mostly all retired by now...