I'm interested to know what kind of heat pump they are using to get up to molten salt temperatures. The only off-the-shelf high temp heat pumps you can find ar

I'm interested to know what kind of heat pump they are using to get up to molten salt temperatures. The only off-the-shelf high temp heat pumps you can find are generally supercritical CO2. To get a high temperature differential with phase change heat pumps, you typically need to use multiple stages or have a very high compression ratio (read: quite expensive compressor). The picture in the background looks like maybe a ceramic turbine? Anyone who has any information on this, I'd be interested to hear more about the details.