Sun hours is one of the parameters used in
Photovoltaic system design in determining whether
installation of a solar system would be recommended for a
particular region, with a minimum of 5 sun hours per day
being a recommended standard. As a result, photovoltaic
systems are preferably installed in areas with long sun
hours and these invariably have high temperatures.
However, studies carried out on the performance of
photovoltaic modules have shown a considerable decrease
in their power output at temperatures above their
optimum operating temperature 25oC. Most interestingly,
research has also shown a decrease in the output power of
a photovoltaic module as it cools down after being heated
to 58°C indicating that high temperatures may cause
premature aging of the module. This research aims to
determine whether the temperatures at which University
of Namibia (UNAM) Faculty of Engineering and I.T
campus’ photovoltaic modules are operated are high
enough to reduce the module power output considerably.
To achieve this, the average operating temperature of the
systems modules for the period of 214 days between 1
March and 30 September 2014 was determined. During
the course of the research it was discovered that 79% of
the insolation received by the system’s modules daily is
received in the time period between 12 pm and 4 pm. In
this report, this time period will be referred to as the peak
insolation period and because the insolation received
directly affects PV power output, particular attention was
paid to the effect PV module operating temperatures have
on the system power output during this period. The PV
system was modeled to a 98.7% mean accuracy using
Matlab Simulink and run at optimum operating
temperature, daily average operating temperature and
peak insolation period operating temperature, for a range
of insolation values. The simulation results show a 0.31%
decrease in system power output per Kelvin increase in
temperature and performance ratios of 0.97 and 0.94
when the simulation is run at daily average temperature
and average peak insolation period temperature
respectively. Finally, using the T test at the 95%
confidence level, the power outputs obtained when the
simulation was run at average operating temperature and
average peak insolation temperature were tested to see if
they are statistically different from the power outputs
obtained when it is run at optimum operating
temperature. The results of the T test showed that the
power outputs obtained at both the average operating
temperature and the average peak insolation operating
temperature are statistically different from the power
output at optimum operating temperature indicating that
the temperature significant decreases the PV system
power output.