2014 IES Street and Area Lighting Conference
September 14-17, 2014 | Nashville, TN
Click here for more information >
Advanced Energy Design Guides: Free Download >
An extensive review of the two current methods for evaluating discomfort glare is provided. This includes a description and assessment of the research on which they are based, their limits of applicability, and what further research is required to extend their use. A bibliography of more than 250 references is provided.
A generalized method is developed for determining the direct sky component in daylighting calculations. Previous analytic methods required that the daylighting aperture be horizontal or vertical. This new methods allows for tilted apertures. Its accuracy is assessed with measurements in a model in a sky simulator.
The spectral composition of light near the vertical cutoff of HID automobile low-beam headlamps is shown to change dramatically with small changes of angle. Measurements of the spectral power distribution in directions near the cutoff are used to determine the shift in CIE chromaticity coordinates. These coordinate shifts are shown for projector and nonprojector HID and tungsten-halogen low-beam lamps. It is hypothesized that large color shifts are responsible, in part, for the reported discomfort caused by projector HID automobile head lamps.
A new type of retrofit metal halide lamp is described which combines the characteristics of ceramic metal halide and high-pressure sodium lamps. The new lamp can retrofit medium wattage high pressure sodium lamps, and provide significantly whiter lamp light. The principle physical, electrical, and photometric characteristics of the new lamp are shown in comparison with those of conventional high pressure sodium lamps.
An automated vehicle-mounted system based on CCD digital video cameras for determining roadway luminance, illuminance and glare is described. Estimates are made of the relationships between grey value of light images from the cameras and lighting parameters. Multi-directional measurements of light output are achieved using multiple journeys and multiple cameras on the same road-segment, which provide data on different observation lines. Interpolation techniques are used to estimate the complete profile and produce illuminance contours.
Eight luminance and radiance sky distribution models area evaluated using luminance and radiance measurements recorded outside of Bangkok. Due to the prevalence of intermediate and cloudy sky condition in the tropics, attention is paid to those models that performed well under conditions other than just the clear sky. A number of the models are acceptable, but no single model performs distinctively well.