Monte Carlo ray tracing method is another approach for solving the optical properties of the curved blind.
Monte Carlo ray tracing method is a statistical numerical method involving using random numbers and probability to analyze the radiative exchange process.
The computer program is written to model the radiative exchange process inside the enclosure formed by two consecutive curved slat blinds.
The mathematical model accounted for the slat thickness effect and edge effect as developed in this study is also included in this model.
The slat surface is divided into small sections along its length.
The incident solar radiation on the slat surface, which is absorbed and reflected, is modeled as the energy ray that leaving the small element of the slat surface in the random pattern until it leaves the enclosure to simulate the interreflection of the radiation in a diffuse manner.
The optical properties of the curved slat blind with thickness having the slat reflectance of 0.5 calculated by using the Monte Carlo method are compared with the results calculated from the developed model in Figs. 13–15.
The agreement between the results obtained from the developed model and from the Monte Carlo method is quite good. The optical properties of the curved venetian blind having the slat reflectance of 0.2 and 0.8 at slat angle of 45 degree calculated from the developed model and from the Monte Carlo method are shown in Figs. 16 and 17.
The agreement between the optical properties calculated from the two methods is quite good for a low reflectance blind. The disagreement between the values of the direct-to-diffuse transmittance and the reflectance calculated from the different methods are amplified as the reflectance of the blind is increased especially when the lower part of the slat is exposed to the sun (profile angle from 0 to 45 degree in the case of 45 slat angle).
The results are shown in Fig. 17 for the curved blind having the slat reflectance of 0.8.