Windows and Daylighting Group

U2 - LBL-20542 ER - TY - JOUR T1 - Scale Model Measurements for a Daylighting Photometric Data Base JF - Journal of the Illuminating Engineering Society Y1 - 1985/ SP - 44 EP - 61 A1 - Mark Spitzglas A1 - Mojtaba Navvab A1 - Jong-Jin Kim A1 - Stephen E. Selkowitz AB - We present initial results of a study to produce a high-precision photometric reference data base using scale model photometry and computational daylighting prediction tools. For this study the SUPERLITE computer code was used. We illustrate the importance and difficulty of fine-tuning the scale model experimental set-up and measurement procedures to produce highly precise results. We discuss the advantage of separating the direct component of illumination from the internal reflected component as an aid to understanding discrepancies between measurements and calculations. We use results of the study to suggest the circumstances in which calculation procedures should be used to generate the references, and those in which the precise scale model photometry is the recommended technique. Further research directions in the field are described. VL - 15 IS - 1 U1 -Windows and Daylighting Group

U2 - LBL-17286 DO - 10.1080/00994480.1985.10748633 ER - TY - JOUR T1 - Defining Daylighting From Windows in Terms of Candlepower Distribution Curves JF - IEEE/IAS 1984 Annual Meeting Y1 - 1984/06// A1 - Mark Spitzglas AB - This work describes a method for evaluating quantitatively the daylight admittance of windows under any outdoor conditions in terms that make it possible to calculate interior light distribution. The work is based on a new concept in quantitative daylight analysis, the Transmission Function Approach, developed by the author while preparing graduate thesis (1976 and 1982) [2], [3], and [4].The visible daylight flux introduced through a window (or other daylight-admitting aperture) can be considered, from the point of view of the internal space, as being emitted from a point source or from a finite-area uniform source. The photometric properties of those light sources are defined in terms of the well-known candlepower distribution curves. The ways in which this approach can be applied for different window designs are demonstrated.This approach to the photometric properties of window systems allows one to translate typical daylighting calculation problems into a format in which they can be resolved using traditional electric lighting calculations or computer codes. Even daylighted-oriented computer codes are limited as to the geometric complexity of the windows they can model--this method eliminates such limitations. It will also contribute to a better understanding and visualization of the photometric properties of various windows and other daylight-admitting elements. This approach, therefore, may also serve as an educational tool. CY - Chicago, IL U1 -Windows and Daylighting Group

U2 - LBL-18087 ER -