WHITE PAPER THERMAL PERFORMANCE COMPARISON: HALOGEN REPLACEMENT VERSUS LEGACY INCANDESCENT LAMPS

Transcription

1 WHITE PAPER THERMAL PERFORMANCE COMPARISON: HALOGEN REPLACEMENT VERSUS LEGACY INCANDESCENT LAMPS By: Juan M. Caamaño Jr. SEPTEMBER 2017

2 INTRODUCTION In 2012, the US department of Energy implemented provisions of the 2007 Energy Independence and Security Act to phase out general-purpose incandescent lamps from the market by setting maximum power consumption criteria for general service lamps. In addition to producing compact fluorescent lamps (CFLs) and self-ballasted LED lamps (SBLEDs), manufacturers also introduced energy-saving halogen replacement lamps. These lamps integrate a tungsten-halogen light capsule inside a glass envelope within an A-line glass envelope and lamp base, resulting in the same form factor as the legacy (traditional tungsten) incandescent lamps. The light capsules within these halogen replacement lamps are similar to those currently used in many desk lamps and cabinet and under-cabinet luminaires and are typically rated from Watts. Due to the halogen cycle, these lamps are more efficient (lumens produced per watts consumed) than legacy incandescent lamps. The halogen replacement lamps in the market are approximately 30% more energy efficient than the legacy incandescent lamps they have replaced (see Table 1). TABLE 1: POWER CONSUMPTION BY LAMP TYPE Lumens, Typical Legacy incandescent Lamps (W) Halogen replacement Lamps (W) Since they operate at higher pressures and temperatures to achieve an increase in energy efficiency and operating life, the surface temperatures of halogen light capsules will be hotter than that of legacy incandescent lamps consuming the same amount of power. As a result, there were concerns from various parties that luminaires designed to use legacy incandescent lamps may not comply with end-product thermal limits if halogen replacement lamps were used. Scope of Study Given the internal construction differences between legacy incandescent and halogen replacement lamps, UL was asked to investigate whether these new, higher efficiency, tungsten-halogen lamps would cause luminaires to exhibit higher operating temperatures than when operating legacy incandescent lamps. The 42W, 52W and 72W halogen replacement lamps that have supplanted the 60W, 75W and 100W legacy incandescent lamps, respectively, were selected for this study due to their widespread residential use. Test Method UL selected a typical ceiling surface-mount luminaire with a single vertically oriented lampholder for conducting comparative temperature testing. The legacy incandescent lamps used (60W, 75W, and 100W) were validated as conforming to the thermal calibration specifications of UL 1598, Luminaires, qualifying them as reference lamps. Both clear and frosted glass envelope designs of the halogen replacement lamps were tested. For page 2

3 additional data comparison purposes, a selection of SBCFL and SBLED lamps were included. The full list of test lamps is shown in Table 2. All lamps were purchased at local home improvement and big box retail outlets in the Melville, NY area. Thermocouples were applied to the various luminaire locations identified in Table 3. These locations represent either critical locations for determining compliance with UL 1598, or contact (touch) surfaces for the end-user. Each thermal test was conducted until all temperatures were deemed stable (three consecutive readings within 1 C, as specified by the temperature stability requirements in UL 1598) but no tests were less than three hours. Data and analysis Figures 1, 2 and 3 show the test results for the reference lamps versus their respective halogen replacement lamps. In each case, and at every thermocouple location, higher temperatures were measured when the luminaire was operating with the reference lamps. While there was some variability in the measured temperatures amongst the different halogen replacement lamps, these variations were relatively small. Where lower wattage CFL or LED replacement lamps were included in the comparison, the measured temperatures were lower still. The data also indicated lower temperatures even when consumers install the next higher halogen replacement lamp, as long as the marked maximum wattage marking on the luminaire is observed. For example: installing a 52 W lamp (marketed to replace a 75 W incandescent lamp) in a luminaire marked for a maximum 60 W lamp. This indicates that as long as end-users continue to comply with the maximum wattage limit in the luminaire s lamp replacement marking, the luminaire should produce less overall heat than with the legacy incandescent lamp that was used to establish this marking. These results confirm the expectation of a direct relationship between wattage reduction and heat reduction for these A-shaped lamps when light output is held steady. For example: a 43 W replacement for a 60 W lamp represents a 28% reduction in wattage. At the lampholder and screwshell terminal, which are the closest locations to the filament itself and thus most impacted by the radiated heat, the temperature drop was 27% and 29%, respectively. The more distant locations (ceiling surface, junction box, and outer globe) showed temperature reductions of 17%, 19%, and 12%, respectively. Similar proportionate reductions in temperature at the lampholder and screwshell terminal are found when comparing the 52 W vs. 75 W (31% reduction) and 72 W vs. 100 W (28% reduction) data. Conclusion Luminaires fitted with halogen replacement lamps exhibited lower temperatures than when operating legacy incandescent lamps with the same form factor and comparable lumen output. These results appear to validate the practice of using energy saving halogen-replacement lamps of matching light output levels as replacements for higher wattage legacy incandescent lamps. This also indicates that, as long as end-users continue to comply with the maximum wattage limit in the luminaire s lamp replacement marking, the luminaire will comply with temperature limits that were used to establish this marking. UL will be monitoring reports of field incidents as a means to determine whether further action on this topic may be needed. page 3

4 TABLE 2: TEST LAMPS Sample Designation Lamp Type Power (W) Lum. Flux (lm) Marked to Replace Lamp Efficacy (lm/w) 60W 60W Reference A Halogen Clear W A Halogen Clear W B Halogen Frosted W B Halogen Frosted W B Halogen Frosted W B Halogen Frosted W B Halogen Frosted W B Halogen Frosted W G CFL W W 75W Reference C Halogen Clear W C Halogen Clear W D Halogen Frosted W D Halogen Frosted W D Halogen Frosted W W 100W Reference E Halogen Clear W E Halogen Clear W F Halogen Frosted W F Halogen Frosted W F Halogen Frosted W F Halogen Frosted W F Halogen Frosted W H CFL W H CFL W K SBLED W K SBLED W 88.4 Note: Power and luminous flux data from lamp packaging. Lamp efficacy calculated using this data. page 4

5 TABLE 3 - LUMINAIRE THERMOCOUPLE LOCATIONS Lampholder surface, 6.4 mm from lip, at 0 Lampholder surface, 6.4 mm from lip, at 90 Lampholder surface, 6.4 mm from lip, at 180 Lampholder surface, 6.4 mm from lip, at 270 Outside center of globe, under set screw #1 Outside center of globe, under set screw #2 Outside center of globe, under set screw #3 Ceiling adjacent to canopy Screwshell wire terminal Junction box temperature probe LAMPHOLDER SURFACE 6.4MM FROM LIP OUTSIDE CENTER OF BULB UNDER SET SCREW SCREWSHELL WIRE TERMINAL page 5

6 FIGURE 1 - LAMP TEMPERATURE DATA 60W GROUP NORMALIZED TO 25 C AMBIENT W 1A 2A 1B 2B 3B 4B 5B 6B 1G Normalized Temperature ( C) Mean lampholder Mean globe hot spot surface, 6.4 mm from lip Ceiling adjacent to canopy Screwshell wire terminal Junction box temperature probe Note: The bars are in the same order as the legend and data point labels Data Points 60W 1A 2A 1B 2B 3B 4B 5B 6B 1G Mean lampholder surface Mean globe hot spot Ceiling adjacent to canopy Screwshell wire terminal Junction box temp. probe page 6

7 FIGURE 2 - LAMP TEMPERATURE DATA 75W GROUP NORMALIZED TO 25 C AMBIENT W 1C 2C 1D 2D 3D Normalized Temperature ( C) Mean lampholder surface, 6.4 mm from lip Mean globe hot spot Ceiling adjacent to canopy Screwshell wire terminal Junction box temperature probe Note: The bars are in the same order as the legend and data point labels Data Points 75W 1C 2C 1D 2D 3D Mean lampholder surface Mean globe hot spot Ceiling adjacent to canopy Screwshell wire terminal Junction box temp. probe page 7

8 FIGURE 3 - LAMP TEMPERATURE DATA 100W GROUP NORMALIZED TO 25 C AMBIENT W 1E 2E 1F 2F 3F 4F 5F 6F 1H 2H 1K 2K Normalized Temperature ( C) Mean lampholder surface, 6.4 mm from lip Mean globe hot spot Ceiling adjacent to canopy Screwshell wire terminal Junction box temperature probe Note: The bars are in the same order as the legend and data point labels Data Points 100W 1E 2E 1F 2F 3F 4F 5F 6F 1H 2H 1K 2K Mean lampholder surface Mean globe hot spot Ceiling adjacent to canopy Screwshell wire terminal Junction box temp. probe page 8