[BostonEnginerd]

Heat pumps are somewhat limited in the heat they can provide. For example, it would be difficult for a heat pump to produce several hundred degrees C temperatures for an industrial process.

For applications in their wheelhouse, though, they are absolutely amazing.

[whatshisface]

There are a couple physical principles that work together to limit solar thermal collectors: heat flows from hot to cold, and mirrors and lenses work both ways. Together, they imply that a solar collector can't heat up anything hotter than the surface of the sun because if the target was hotter than the sun, it would heat the sun up and not the other way around. The surface of the sun is 5.7 thousand Kelvin. This is enough to melt, but not boil tungsten, which I must imagine is a major issue for the tungsten gas industry.

[im3w1l]

This is probably irrelevant, but due to the finite speed of light the target would be radiating to the place the sun was, rather than the place it will be.

[berkes]

But if you compress the energy collected on a large surface onto a small surface, getting higher heat should be possible, not?

[Jiocus]

The article brings this up towards the end,

"These [eddy current heaters/induction heaters] are comprised of a magnet mounted on a rotating shaft, and can reach temperatures of up to 600 degrees Celsius. Using eddy current heaters, windmills could provide direct heat at higher temperatures, making their potential use in industry even larger."

[stephen_g]

There's plenty of research going into very high-temperature heat pumps. It's likely that eventually that will absolutely be 'in their wheelhouse'. Sure, the COP might only ever be something like 2-3 instead of lower temperature heat pumps (under 80 or so °C) that can be > 4 COP but still should be more than 1...