The system developed at the University of Lleida (Figure 1) is a two-axis sun tracking system using water as a working fluid. The absorber has 72 mono-crystalline Si solar cells which are adhered on top of two circular tubes. Water runs in these tubes to cool down the cells thus enhancing their efficiency and the outlet water is guided to a storage tank where it can be further utilized for domestic hot water production or running a solar-driven chiller. The 12 m2 reflecting system (receiver) is composed of 30 white mirrors that reflect light onto the PV focus band of 0.10 m width and 3.90 m long. The mirrors are of equal length but have unequal widths and are installed at various tilt angles. The solar cells are illuminated by approximately 22 times the solar beam irradiance. The generator’s rated power is 1 KWectrcial and 4 KWthermal.