Therefore, the value of the measured transmitted solar radiation from the inside pyranometer, which is based on the actual incident solar radiation on the glass window surface, is lower than the value of the predicted solar radiation, which is based on the solar radiation measured from the outside pyranometer.
After the time of 14.00 the effect of the shading from the vertical slab and the set back of the glass window surface from the sensor is diminished as the sun is traveled toward the west direction and it is facing directly on the glass window surface.
The agreement between the measured data and predicted data becomes quite good again.
With the certain limitations due to the location of the test room and instrument installations, the predicted results from the developed mathematical model are proved to be quite accurate within the estimated uncertainty.