2014 IES Street and Area Lighting Conference
September 14-17, 2014 | Nashville, TN
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This article presents the results of a study where the effect of five window glazing types on daylight quality was investigated using a scale model (1:6) of a room with a single, east- oriented window exposed to the natural sky. The space studied simulated a typical, fully furnished living room. A total of 30 research subjects took part in the experiment, observed the room and filled questionnaires, which covered seven factors related to daylight quality: light level, glare (comfort), naturalness, beauty and pleasantness, precision, light distribution and shadows. This study repeated some results from previous investigations although a different experimental design was used. The results of the statistical analysis (ANOVA) indicated that the glazing type had a statistically significant effect on the perception of light level, naturalness, beauty/pleasantness and precision. The visual transmittance of the glazing type was positively correlated with light level, glare (comfort), naturalness, beauty and pleasantness, and precision. The glazing type had no statistically significant effect on light distribution and shadows. The results also suggest that a color distortion in two directions yields more positive votes compared with a unidirectional color shift.
The International Commission on Illumination has adopted a set of fifteen standard sky luminance distributions (SSLD). One of our previous papers uses a least squares method to sort sky luminance measurements from a station located north of Bangkok into fifteen slots, each corresponding to each type of SSLD, to appraise the statistics of occurrence of each sky type at the location. The paper also uses Kittler’s method (Kittler; et al. 1997) to prepare paired values from the measurements sorted and obtains parameter values of the gradation function and those of the indicatrix function separately from measurements in each slot. This paper applies evolutionary computation to obtain a set of parameter values for both gradation function and indicatrix function simultaneously under least squares criterion. This method enables all measurements in each slot to be used. The resulting luminance distribution function thus obtained for each sky type possesses lower bias error and lower mean square error than those of the corresponding type of SSLD when both are evaluated against measurements.
Electric lighting is responsible for consuming approximately twenty-two percent of the electrical energy generated domestically, second only to that consumed by electric machinery. Of this quantity, approximately fifteen percent of the lighting energy usage is by those lighting products that fall within the category termed High-Intensity Discharge (HID). HID sources, which include Mercury Vapor, Metal-Halide, and High-Pressure Sodium, range in power level from 35 to 2000 watts. Luminaires equipped with these sources are used in outdoor lighting applications and also indoor applications, one category of which is the focus of this article - the illumination of industrial facilities. The term “lighting system” is used in this article to describe all of the elements required to illuminate the target area to required levels. This includes lamps, ballasts, housings, optical assemblies, support structures, and any other components involved in the operation and maintenance of the lighting system
Efforts to reduce energy consumption most often revolve around the use of more efficient or efficacious lighting products which will be successful in providing the desired photometric results. In general, the more efficient the system in converting electrical energy to visible energy, the more expensive are the source and associated control gear. Consequently, the relationship between acquisition cost and performance is a major obstacle in an effort to convince users to install more efficient lighting equipment. This article reviews the performance characteristics of the various HID lamp families that are used domestically in industrial lighting applications. This includes selected energy consumption profiles, cost breakdowns, and life-cycle cost analyses of various HID lighting systems for the purpose of offering guidance to those who are responsible for the selection and application of lighting products. Also provided is an in-depth investigation into the impact of lighting system maintenance upon the energy consumption and overall cost of a lighting project as projected using life-cycle costing techniques.
This study provides information about average annual use of the following automotive lighting equipment by U.S. drivers: low-and high-beam headlamps, turn signals, and stop, back-up, parking, sidemarker, and tail lamps. The data were collected as part of a naturalistic field study of crash warning systems. Eighty-seven randomly selected drivers from southeastern Michigan were provided with instrumented research vehicles for periods averaging 26 days and instructed to drive the vehicles as their personal vehicles
The results are presented for each lamp type in terms of the average annual hours of use and minutes used per mile driven. These findings are discussed in relation to the rated life of various bulbs and the average life of vehicles in the U.S
License plate, parking, sidemarker, and tail lamps were the most frequently used automotive lighting equipment, averaging just over 100 hours per year. The least used lamps were back-up lamps, which were used less than five hours per year. Average annual hours of lamp use decreased with increasing driver age. While rates of use for stop, turn signal, and back-up lamps were similar for females and males, male drivers accrued 34 percent more hours of nighttime driving than female drivers, while using their high beams about half as often.