We present results from the first phase of a project to develop a fenestration performance design tool to be used by builders, designers, architects, utility auditors, etc. In phase 1 we defined the design tool concept and the experimental and analytical methodologies required to achieve the project goal. We defined five fenestration performance indices, which when combined with user-specified weighting factors yield a single figure of merit. Three of the indices are related to the effects of fenestration on building energy performance: fuel and electric use and peak electric demand. The other two are related to thermal and visual comfort. We derived index values and correlations to window design parameters by creating a data base consisting of a large number of building energy simulations for a prototypical office building module using the DOE-2 computer simulation program. Four glazing types and two shading devices were combined in several ways so that a representative sampling of realistic fenestration systems was analyzed.

1 aSullivan, Robert1 aArasteh, Dariush, K.1 aPapamichael, Konstantinos, M.1 aKim, Jong-Jin1 aJohnson, Russell1 aSelkowitz, Stephen, E.1 aMcCluney, Ross uhttps://buildings.lbl.gov/publications/indices-approach-evaluating02097nas a2200169 4500008004100000050001400041245008200055210006900137260002800206520149400234100001801728700003401746700002701780700002001807700002401827856007601851 1986 eng d aLBL-2054200aDetermining Daylight Illuminance in Rooms Having Complex Fenestration Systems0 aDetermining Daylight Illuminance in Rooms Having Complex Fenestr aLong Beach, CAc11/19863 aTraditional computational models predict daylight illuminance in a space by dividing window surfaces into discrete areas and then calculating the apparent luminance of each window element by multiplying the luminance of the natural light source in a given viewing direction by the window transmittance in that direction. This approach works well for conventional glazing materials but is incapable of modeling commonly used, but complex, window systems such, as those with specular reflective venetian blinds. We describe a new approach that combines measured luminance distributions for complex window systems with a flux transfer calculation within the space. This method resembles the calculation of illuminance from electric light fixtures where the candlepower distribution of the fixtures is measured and used as an input to the calculation. Based on the variable luminance characteristics of the window system, the SUPERLITE program calculates illuminance at the workplane over the entire space. The measurement techniques and mathematical implementation in the SUPERLITE program are described. This approach allows a wide range of complex window and shading systems to be evaluated without continuous changes in the computational program. A special apparatus for measuring the bidirectional transmittance of window systems has been built in conjunction with this approach. Sample results from the program are compared to measurements made in scale models in a sky simulator.

1 aKim, Jong-Jin1 aPapamichael, Konstantinos, M.1 aSelkowitz, Stephen, E.1 aSpitzglas, Mark1 aModest, Michael, F. uhttps://buildings.lbl.gov/publications/determining-daylight-illuminance01794nas a2200145 4500008004100000050001400041245009100055210006900146260002800215520125000243100001801493700003401511700002701545856007601572 1986 eng d aLBL-2053900aDevelopment of Regression Equations for a Daylighting Coefficient-of-Utilization Model0 aDevelopment of Regression Equations for a Daylighting Coefficien aLong Beach, CAc11/19863 aWhen hourly energy simulation models are used to predict the performance of multi-zone buildings, they may be required to perform more than 2,000 daylight analyses in a single simulation. The traditional approach is to use a very fast computational model, which of necessity must be a very simple model. Coefficient of utilization models have been widely used as simple design tools but have been severely limited in their applicability to complex and realistic fenestration systems and building designs. This paper present a new coefficient of utilization (CU) model for daylighting that combines the ease of use of CU models with the ability to predict illuminance under a wide range of conditions. The model consists of seven regression equations normalized to exterior vertical surface illuminance. These equations describe daylight illuminance as a function of position in a room and are sensitive to all of the significant design variables. The equations are derived from parametric analysis using a mainframe daylighting computer model (SUPERLITE). We describe how these equations were developed and their physical and theoretical background. Comparisons between direct calculation and CU results for sample rooms are demonstrated.

1 aKim, Jong-Jin1 aPapamichael, Konstantinos, M.1 aSelkowitz, Stephen, E. uhttps://buildings.lbl.gov/publications/development-regression-equations01381nas a2200157 4500008004100000245006900041210006900110300001000179490000700189520086200196100002001058700002001078700001801098700002701116856008001143 1985 eng d00aScale Model Measurements for a Daylighting Photometric Data Base0 aScale Model Measurements for a Daylighting Photometric Data Base a44-610 v153 aWe 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.

1 aSpitzglas, Mark1 aNavvab, Mojtaba1 aKim, Jong-Jin1 aSelkowitz, Stephen, E. uhttps://buildings.lbl.gov/publications/scale-model-measurements-daylighting00825nas a2200157 4500008004100000050001400041245004900055210004400104260001800148520033100166100002700497700001800524700002000542700003000562856007500592 1982 eng d aLBL-1456900aThe DOE-2 and Superlite Daylighting Programs0 aDOE2 and Superlite Daylighting Programs aKnoxville, TN3 aWe describe the capabilities and limitations of two daylighting computer programs, the algorithms used in each, results of validation studies, and sample results using each of these programs. We also describe features now under development for both programs which should further extend their usefulness as design tools.

1 aSelkowitz, Stephen, E.1 aKim, Jong-Jin1 aNavvab, Mojtaba1 aWinkelmann, Frederick, C. uhttps://buildings.lbl.gov/publications/doe-2-and-superlite-daylighting