5.1 CONCLUSIONS
The key outcomes of the experimental study are:
1. The mean force (along x and z axes) and pitching moment coefficients obtained
during the wind tunnel study for twin arrangement (A2) of PV panels were in a
good agreement with the results of a prior related investigation.
2. The drag force coefficient was reduced when PV panel porosity was introduced.
The peak and standard deviation values exhibited higher levels of the reduction
than the mean values.
3. The lift force coefficient was the largest at 30
o
pitch angle for 0
o
and 180
o
wind
directions. Relatively weak impact of the PV panel porosity, for wind direction of
180
o
, was found on the mean, standard deviation and peak lift force coefficients.
Lift force on the porous models at wind direction of 0
o
was lower than that on the
non-porous model.
4. Normal force coefficients for the porous models decreased with an increasing
porosity. These reductions for the mean and fluctuating components were more
pronounced for wind direction of 0
o
than for 180
o
. The porosity effects were
small for the quadruple arrangement of PV panels.
5. The pitching moment coefficient exhibited a maximum reduction of 35%, for the
twin arrangement of PV panels. Minimal reduction in pitching moments was
23
observed for PV panels with quadruple arrangement. The pitching moment was
found to be highest for the PVT pitch angle of 30
o
, for wind flowing normal to the
pivot axis.
6. Introduction of porosity was not effective in reduction of wind forces on the
tracker with quadruple arranged PV panels.
7. Design wind loads were calculated for the prototype scale of PVT using the
normal force coefficients obtained from the wind tunnel tests and compared with
ASCE 7-05 standard results for 0
o
and 180
o
wind directions. The peak design
forces from wind tunnel results were found to be in good agreement with the
ASCE 7-05 based design loads.