The overall installation comprises the following sub-systems : a) Concentrating Solar Thermal Collector Field (PTC). b) Heat Exchanger, the primary loop of which is hydraulically, in-series connected to the collector field, while the secondary loop is respectively connected to the thermal storage tank for medium temperatures (100 έως 300 oC). c) Air-cooled heat rejection unit (Dry Cooler), which is hydraulically connected to the thermal storage tank d) Suitably arranged hydraulic loop, allowing for heat transport from the collectors to the storage tank and the rejection of heat from the tank to the surroundings by means of the heat rejection unit (dry cooler). e) Suitably designed systems for filling up and flushing the entire hydraulic loop. f) Electric heater of 30 kW, to be used as an auxiliary energy source, connected to the storage tank g) Electric installation used for supplying the full set of operations of the individual subsystems.