Otanicar etal. [48] examined the effect of different nanofluids
(carbon nanotubes,graphite and silver) on the performance of a
direct absorption collector experimentally and compared the
results with numerical models. Fig. 4 demonstrates the schematic
of the setup which is a micro solar-thermal collector with a
35 cm2 surface area and 150 μm channeldepth;they use da
Super PAR64lamptosimulatethesolarspectrum.