Figure 4.7. Validation data for fans and misters.
Sensitivity to the Solar Radiation Constant
The τb values for the fans and the misters were determined in a calibration step assuming
the solar radiation to be an average over the entire month of June 2011. In an effort to
identify the sensitivity of the model on the solar radiation value, predicted temperatures
based on an average over a month were compared to predicted temperatures based on the
same day (using the calibration data). The results are shown in Figure 4.8. For the fans,
the RMSE when using the same day solar radiation was 1.64, while it was 1.41 when
using the average solar radiation. For the misters the RMSE when using the same day
radiation was 1.7, while it was 1.47 when using the average solar radiation. These results
suggest that we can use an average solar radiation in the model. However, the length of
time over which the solar radiation is averaged should be based on the data over the
entire year. It may be taken over a 30 day period or over shorter periods of time. This will
be determined when addition temperature data are available.