LBNL Report Number
This study has measured the performance of energy-saving 34-watt F40, T-12, rapid-start, lite white fluorescent lamps being operated by solid-state ballasts and lighting control equipment. The performances of these lamp systems are compared with those of 40-watt F40, T-12 rapid-start cool white fluorescent lamp systems studied in the prior phase of this project.
With the 34-watt F40 lamps and various solid-state ballasts, system efficacy ranged from 67 to 84 lumens per watt and ballast factor from 0.756 to 0.908. Average system efficacy using the 34-watt lamps exceeded that of systems using 40-watt lamps and the same solid-state ballasts by only 1 percent even though the 34-watt lamps is about 6 percent more efficacious than the 40-watt lamp. This apparent discrepancy is due to increased ballast losses when operating the 34-watt lamps. However, the system efficacy of the 34-swatt lamps used with a solid-state-ballast exceeded that of a 34-watt, two-lamp system using the standard core-coil ballast by as much as 29 percent.
A T-8 fluorescent lamp system with a smaller lamp diameter was also included in the study. Operating this lamp with a solid-state ballast produced a high system efficacy of 90 lumens per watt, a 39 percent improvement over the efficacy of a 40-watt F40 system using the standard core-coil ballast.
The use of static controllers with 34-watt F40 lamps can result in excessive flickering (46 percent) and the generation of a second harmonic as high as 96 percent of the fundamental frequency.
The dynamic controllers, when used to dim the 34-watt lamps generally cannot be dimmed as low as the 40-watt lamp system without flickering.
In general, the 34-watt energy-saving lamps are appropriate as a retrofit to reduce illumination levels. However, for new construction, the 40-watt F40 argon filled lamps cost less, perform better, and provide a more reliable system.