Futurology

I was really excited about this concept for a bit. There's all kinds of high-boiling liquids, if you're okay with a hot "cold end" as well. The trick is that ideal heat pumps are efficient exactly when heat engines aren't, so if there's a big gap between the ends you're better off just using resistive heating.

I'm glad to hear they've found a niche for just above boiling, though!