Hay look that, a 80% efficience solar system being developed :
https://cleantechnica.com/2013/04/24...-conditioning/
But the last system needs 3 axis tracking, which elevate a lot6 the price of manufactre. A samll 2 axis system, like the image bellon, would be cheaper, and they would need just linear solar cells (in the tube line in the center):
BUT THERE IS A TRICK, since like the Israel system (very similar) it counts the hot water (used to cool the photovoltaic cells) in the total energy, even if it's mostly heat energy of hot water and not just the electric energy. If the high efficience solar cells could operate well, at higher temperatures, they could boil the water and move a turbine for aditional electric power.