Bidirectional Optical Properties of Slat Shading: Comparison between Raytracing and Radiosity Methods
نویسندگان
چکیده
The Window 6.0 computer program incorporates a model for calculating the optical properties and solar heat gain factor of slat shading systems. This model adheres to the framework appearing in the ISO 15099 standard, which is based on a radiosity approach. Only the directional-hemispherical properties of the slat shading can be predicted by the method of ISO 15099. Extensions to the Window 6.0 implementation enable the calculation in full bidirectional detail. A detailed raytracing model based on a Monte-Carlo method is compared to the Window 6.0 radiosity implementation. Directional-hemispherical values are in excellent agreement for all conditions. Bidirectional results are in good qualitative agreement. Simplifying assumptions in the Window 6.0 model such as zero-thickness slats and segmented slat curvature are shown ∗ Corresponding Author, email: [email protected], fax: 510.486.7124 to have little detrimental effect except in certain cases. One significant limitation of the radiosity approach is the inability to model specular slat properties.
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