Thermodynamic

The best efficiency (and as consequence the smallest solar field size) may be obtained by using a Rankine cycle, using widely known technology installed in thousands of combined cycle power plants.

This solution could offer decreased technical risks and minimized dimension of the solar field.
Nevertheless, it must be added that plants of this type require  vast quantities of water to compensate the usual losses (ca. 8-10 m3/day), function with elevated pressures and require  regular and qualified maintenance.

Operating the solar field at the highest possible temperature level is necessaryin order to obtain  increased efficiency. This requires iterative design with solar field development. By using air as exchange fluid, this task can easily be achieved as much higher operation temperatures are possible compared to current thermal oil technology.
 

The efficiency increase from 400°C with oil to 525 or more with Air is dramatic.

Thermodynamic general schema