Abstract:
The performance of nanofluid-based solar collector depends on different factors like nanoparticle material, base fluid, mass
fraction of nanoparticles, height of the collector, length of the collector, incident solar flux, mass flow rate of the nanofluid
in the collector. In order to quantify the effect of nanoparticle material, optical properties of different nanofluids (different
nanoparticles dispersed in DI water) were measured using spectrophotometer. After studying the optical signatures of the
nanofluids, solar-weighted absorptivity of the nanofluids was calculated to evaluate the efficient nanoparticle material for
harnessing solar irradiation. It has been found that amorphous carbon nanoparticles-based fluid has highest absorptivity at
low mass fractions and is suitable for harnessing solar energy. Further, the performance of nanofluid-based solar collector
has been investigated numerically using amorphous carbon nanoparticles. For the purposes of this analysis, a twodimensional steady-state heat transfer model has been developed for a collector in which the nanofluid flows horizontally
and is heated with normally incident solar irradiation. During the analysis carried out in this study, five factors were chosen
(height of the collector, nanofluid mass flow rate, solar irradiation incident flux, nanoparticle mass fraction, and length of
the collector). The influence of variation in these five factors on the overall performance of the solar collector (i.e., outlet
temperature) was analyzed using the Taguchi method. In order to carry to this analysis, the values of these five factors were
varied at three levels. Based on these variations, the L18 standard orthogonal array was prepared, and the matrix containing
the 18 sets of combinations was organized. The results showed that two factors (length of the collector, and the incident
solar flux) exhibited a strong increasing trend, while one factor (nanoparticle mass fraction) exhibited an optimizing trend
on the output (outlet collector temperature). Further, from the calculations it has been observed that 60 mg L-1 is an
optimum mass fraction at which maximum collector efficiency can be achieved for the length of the collector (= 1 m),
height of the collector (= 10 mm), incident flux (= 1000 W m-2
), mass flow rate (= 0.010 kg s-1
).
