470
S. Mohan et al.
Fig. 3 Transmittance spectrum of 0.02% CuO, 0.025% TiO 2 , and ethylene glycol
3.3 Temperature Profile
During the experimentation, it was found that on using water as the fluid medium, a
temperature of 44 °C was achieved meanwhile, and in case of pure ethylene glycol,
it was heated to a temperature of 53 °C. While in the case of hybrid nanofluid, a
temperature of 70 °C was noted. This reading shows that the hybrid nanofluid is
capable of absorbing more heat than base fluid. The amount of heat absorbed can
be increased if the surface area of the experimental setup is increased, and as area
increases, there will be more amount of heat absorption, which in turn enhances
the performance. It was evident form the literature that the absorptivity is a direct
function of photo-thermal conversion. Hence, photo-thermal conversion increases
with the absorptivity of the nanofluid. Further, the energy absorbed by the nanofluid
could be quantified using the following energy equation.
Q = mC p (T in − T out )
(2)
As per this equation, the photo-thermal conversion increases with the temperature.
As the outlet temperature of hybrid nanofluid is higher than the base fluid, the photothermal conversion is high for the hybrid nanofluid.