I dare say someone from the oil industry bought the patent then secreted it away

They used to have an inventors show here in Oz like 20+ years ago. Remember seeing this guy had made a cylinder made of prisms directing sunlight to the center, about 30cm diameter. There he had black pipe with the idea you have oil in it which can be super heated. He reckoned 3 meters of his cylinder in the sun was enough to heat the oil enough it could then be run through water to generate steam ie generate electricity. Spent an afternoon on the net looking for that episode, no-where to be found.

@puff Oil industry blocked it or...it didn't really work.

@FvckY0u 1994