Michael Siminovitch

Fifty percent energy savings with automatic lighting controls

An electronically ballasted lighting control system was demonstrated at an office building in the San Francisco Bay Area. The system was used to demonstrate the energy savings and demand-reduction capabilities of a lighting control system designed to exploit all major control strategies, including scheduling, daylighting, and lumen maintenance. After 9 months of operation, lighting energy savings of approximately 50% relative to previous usage have been consistently achieved. A novel, two-part control photocell that permits successful implementation of daylighting and lumen maintenance strategies was demonstrated. >

50% energy savings with automatic lighting controls

An electronically ballasted lighting control system that was demonstrated at an office building is described. The system demonstrated the energy savings and demand reduction capabilities of a lighting control system designed to exploit all major control strategies, including scheduling, daylighting and lumen maintenance. After nine months of operation, lighting energy savings of approximately 50% relative to previous usage have been consistently achieved. A two-part control photocell, shown to be effective at maintaining light levels at the workplane regardless of the daylight contribution, is presented.<<ETX>>

Control of lamp wall temperature

A review of techniques to control the lamp-wall temperatures of fluorescent lamps in luminaires is presented. Past results show that large increases in efficacy and light output can be obtained (to 25%) if the lamps can be operated at their optimum lamp-wall temperature. Their cost-effectiveness is reviewed in view of the increased energy cost and advances in the technology.<<ETX>>

The effects of fixture type and HVAC integration on fluorescent lamp/ballast performance

The effects of fixture type and lamp compartment air extract on lamp/ballast performance are described. A luminate/plenum/HVAC simulator was used to measure minimum lamp-wall temperature inside four fixture types while varying lamp-compartment extract conditions. Experimental data show that the lumen output of the lamp/ballast system varies by 20% and system efficacy by 10% depending on the type of fixture and lamp-compartment extract technique used. >

The Energy Case against Halogen Torchieres

ABSTRACT While a mountain of press has attacked halogen torchieres regarding safety concerns, little attention has been paid to their massive energy consumption. At LBNL, a series of commercial 300-Watt tungsten halogen torchieres have been studied in order to determine their energy use, power quality, and photometric performance. This work has served as the background for an ongoing program aimed at developing novel high-efficiency torchieres using compact fluorescent lamps (CFLs). Experimental data is presented indicating a wide range of lumen output, power input, and efficacy characteristics for halogen torchieres. Typical imported torchiere systems can have a relatively low system efficacy in the range of 5-10 LPW depending on the specific source, dimming methods, and optical characteristics.

Comparative Candlepower Distribution Analysis for Compact Fluorescent Table Lamp Systems

The residential lighting sector represents a significant opportunity for energy conservation due to the almost exclusive use of inefficient incandescent sources. Compact fluorescent lamps (CFLs) have the potential to transform this market by using one fourth as much power as an incandescent to provide the same amount of light. While technical advances such as triphosphors and electronic ballasts have addressed issues of color rendition, flicker, and hum, CFLs still face significant market barriers, particularly their ‘perceived brightness’ level in traditional fixture applications. When operated in fixtures originally designed for A-lamps, CFLs with equal total lumen packages can appear dimmer due to differences in their light distributions. One such fixture, the common table lamp, is typically operated for more than 3 hours a day, and thus represents a significant opportunity for energy savings. LBL conducted a series of goniophotometric candela distribution studies of table lamps with the initial objective of matching with CFLs the light distribution of the consumer accepted A-lamp. While goniometric testing was done on numerous CFL and incandescent sources, this paper focuses on three typical sources which have very different distributions. Our photometric studies indicate that horizontally oriented CFLs may produce a more desirable distribution than either A-lamps or vertically oriented CFLs by minimizing shade losses and thus maximizing the amount of useful light leaving the fixture. Optimizing fixture geometry and lamp position can significantly increase the efficiency of these CFL fixtures. Ongoing research with the fixture industry seeks to identify and develop efficient source/fixture configurations. Introduction In 1994, the 96 million households in the United States used an average of 1,500 kWh of electricity for lighting. Thus, residential lighting accounts for around 145 billion kWh per year. Illumination in the home is provided almost exclusively by incandescent sources with efficacies of approximately 15 lumens per watt. Replacing these sources with 60-70 lumen-per-watt compact fluorescent systems would create very significant energy savings. The average compact fluorescent lamp can reduce the energy consumption in a traditional incandescent application by approximately 75%.1 Recent studies indicate that 70% of residential lighting energy is consumed by just 30% of a typical home’s fixtures, called ‘high-use’ sockets.2 A significant portion of these high-use sockets are table or floor lamps and could be replaced with either CFL retrofits or ‘dedicated’ CFL fixtures.3 But replacing an incandescent A-lamp with a CFL changes the fixture’s optical distribution, potentially reducing perceived brightness and adding to consumer dissatisfaction. In order to characterize the differences in candlepower distribution associated with different sources, a series of photometric studies were conducted using a swing-arm goniophotometer. Computer controlled tests generated standard photometric reports with candela plots, zonal lumen summaries, and total lumen output. These results were then compiled into a comprehensive database of goniometric reports that provide basic information as to how different sources perform within typical shaded table lamp systems. The information from these studies will aid in the development of highefficiency ‘dedicated fixtures’ that use CFLs as the source. Initial goniometric studies focused on how well retrofit screw base CFLs work with shaded lamps. Since the sides of a CFL’s tubes produce most of its light, we theorized that the lamp shade

Lighting retrofit study

A study conducted to determine the most cost-effective methods of retrofitting several configurations of lighting systems at Lawrence Berkeley Laboratory (LBL) and Lawrence Livermore National Laboratory (LLNL) is described. A test protocol was developed to compare several of the most commonly utilized retrofit options for their applicability in labs and offices. A novel lighting contrast potential meter was designed and constructed to allow comparison of lighting quality as well as quantity. In addition the performance of the various retrofits, factors affecting their installation and operation were investigated.<<ETX>>

Variations in temperature and performance in a standard and thermally bridged compact fluorescent fixture

The spatial temperature distribution in an enclosed, screw base, 13 W compact fluorescent retrofit fixture and the surrounding environment was investigated for a typical recessed fixture application. The minimum lamp wall temperature and light output were measured over time with and without a thermal bridging system. The experimental data were used to design an efficient thermal bridge and to evaluate the performance of the bridge, which was found to increase the relative light output of the fixture of about 20%.<<ETX>>

Contrast potential, an assessment technique using large solid angle illuminance measurements

The authors describe a technique for assessing the luminous contrast within lighting environments. This technique uses large solid angle measurements of both vertical and horizontal illuminance on the work plane, and is based on combining the horizontal and vertical illuminance measurements with a simple expression. This illuminance function was compared with the luminance contrast measurements obtained with a luminance contrast meter. Analysis of the experimental data indicates a strong correlation between the illuminance-based procedure and data obtained with the meter. The assessment of contrast based on large solid angle measurements of illuminance is also described.<<ETX>>

Convective venting in compact fluorescent fixtures

Convective venting studies done on three different compact fluorescent fixtures indicate that the reduction in light output and efficacy caused by a highly constricted thermal environment can be nearly eliminated with a proper venting configuration. Experiments conducted on an open, recessed ceiling fixture housing two 26 W, quad-tube, compact fluorescent bulbs indicate a light output loss of 15% for an unvented fixture; with an aperture area of approximately 1.5 square inches (a 0.5 in*3.25 in vent) placed in the top of the fixture, thermally-induced light output losses are reduced to about 3%, while optical losses due the apertures size are only about 4%. In an enclosed recessed fixture, housing two 13 W, twin-tube bulbs, light output and efficacy losses are noted at 18%; both of these decrease to only 2% losses with two small, lower vents and a larger, upper vent introduced to the fixture. In a smaller, enclosed, recessed downlight, housing two 7 W bulbs, losses for both the light output and efficacy of the fixture are originally noted at 10%; with three vents introduced to the fixture (in the same configuration as the other enclosed fixture), light output reached at 98% of maximum, and lamp efficiency reached 96% of maximum.<<ETX>>