The effect of using the 1-nm single-walled carbon nanotube
(SWCNT)/H20 nanofluid on the performance of a
natural-circulation FPSC was studied experimentally by
Vijayakumaar et al. (2013). Two identical 0.34-m2 flat plate
collectors were fabricated (Fig. 17). The weight fractions of
nanoparticles were kept at 0.40%, 0.50%, and 0.60%, the
mass flow rate of the nanofluid varied around 5 l/min,
and Polysorbate 80 was added as a surfactant. The collector’s
absorber plate and tubes were copper, and it had a
single 5-mm glass cover; a 50-mm thickness of glass wool
insulation was used. ASHRAE Standard 93 was selected
as a basis for calculating the efficiency of the collector.
Tests were performed between 11:00 A.M. and 2:00 P.M.
Compared to water, the results showed a maximum
increase in the efficiency of the collector of 39%
using 0.5 wt% SWCNT/water nanofluid.