With the slat optical properties given in Table 2 and the glass optical properties given in Table 3, the longwave optical
properties of the glass window and the installed venetian blind is then determined from the method described above.
The calculated longwave optical properties along with the measured solar radiation, outdoor temperature,indoor temperature and wind velocity are used as the input parameters for the mathematical model described in Eqs.(37)–(72). The surface temperature of the venetian blind modeled as the effective layer can be determined. The analyzed surface temperature of the blind at +45 and 0 slat angle are compared with the measured values in Figs. 13–16.
The measured global radiation data is also presented in Figs. 13–16.
Because the glass window is facing west and has 1.5 m exterior roof projection over the testing room, the direct solar radiation is fully incident on the glass window at the time about 14:00.
This can be clearly seen on the pattern of the measured global radiation shown in Figs.13–16. For the blind temperature, It can be seen that the pattern of the measured and simulated blind temperature follow the pattern of the incident solar radiation.
There was a short period of rain during the time between 14:15 and 15:10 while the measurement was performed on the
green blind at slat angle of +45.
The effect of rain on the measured global radiation values during that period is shown in Fig. 15.
The agreement between the measured values and the predicted values of the blind temperature is quite good for all cases. The resolution of the used infrared radiometer is 1 C.
The deviation between the measured values and the predicted values is probably due to the error introduced from the measurement method and measurement instruments.
The magnitude of the deviation is mostly within the instrument resolution.
The experiment in this study is rather crude.
The agreement between the simulation results and measured data is encouraging.
Better measurement methods and measurement instruments are needed for better validation.