IMPROVING THE PERFORMANCE OF INTEGRAL SCREW-BASE COMPACT FLUORESCENT LAMPS IN A BASE-DOWN BURNING POSITION USING THERMAL BRIDGE SYSTEMS

Many residential applications of the integral-ballast, screw-base comp act fluorescent lamp (CFL) require base-down orientation, as exemplifi ed by table and floor lamps. Positioning CFLs base down results in a 1 0-25 percent loss in lumen output, due to excess mercury vapor pressur e in the lamp. These losses may limit consumers' acceptance of these n ew CFLs as a viable retrofit strategy. To mitigate output losses, rese archers are developing thermal bridge systems that cool the small tubu lation of the lamp, thereby optimizing mercury vapor pressure. Thermal bridge systems comprise small copper heat sinks that fit entirely wit hin the integral-ballast compartment. Experiments indicated that most of the thermally based losses are recoverable, allowing for a lamp sys tem that produces approximately the same lumen output regardless of or ientation. As base-down positioning has wide residential application, the improved lumen output of these lamps would have a significant impa ct on residential retrofits.