ALTERNATIVE ENERGY FORUM - etc.

This one has a parabolic reflector for higher temperatures and less footprint, but requires solar tracking mechanism.
I built one in 1965 that just heated water and the water was hot enough to burn my fingers [ maybe >150 degrees]. I use aluminized mylar film for the reflector back then.
The STEG "Solar Thermal Electric Generator module" requires that one side be heated and the other cooled, to generate electricity, so that's the reason for the water cooling, the byproduct being, heated water, that can be utilized for showers etc.

https://drive.google.com/file/d/1ERT7MYdnaTH0L-Eul6pC66xsrWUE0rT1/view?usp=drivesdk