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LED Replacement for T8 Fluorescent Lamps: Brief Report on Market Assessment and Testing

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LED Replacement for T8 Fluorescent Lamps: Brief Report on Market Assessment and Testing LED Replacement for T8 Fluorescent Lamps: Brief Report on Market Assessment and Testing Prepared by: University of Alaska Fairbanks Bristol Bay Campus Sustainable Energy Program February 2016 Background information and desired LED characteristics This project took place from April 2015 to February 2016 and the purpose was to find a suitable LED replacement for standard 4’ T8 32W fluorescent lamps with the intention to save energy and money. These were the approximate LED characteristics sought in this project: System power (including the whole system, not just lamps) less than 16 W per lamp Illumination on surfaces (walls, desks, etc.) comparable to standard T8 32W fluorescent lamps when used in standard troffer‐style diffuser‐covered luminaires Eliminates 60‐Hz related flicker (this flicker was found to be a problem in some LED lamps utilizing internal drivers) Verified to meet appropriate UL standards for a field installation of the LED (for example, some LEDs were found to be UL verified as components only, which means they are not intended for field installation as they are a subject to further UL verification of the whole system) Manufacturer with a substantial track record + at least 5‐year warranty Performance third‐party tested using LM‐79 test RoHS certified to help ensure environment friendly materials This project focused on one‐for‐one replacement of the T8 fluorescent lamps with the LED lamps. Comparable illumination levels might also be achieved by using higher power LED lamps with higher light output and delamping at the same time (for example, replacing three T8 fluorescent lamps with two LED lamps), however, this option was not analyzed in this project because delamping might not always be possible (for example, some luminaires only use one lamp). Methods and results Methods included an extensive search of the LM‐79 database (which has over 7000 linear LED products), gathering information directly from manufacturers, and testing selected products. Two categories were considered in this project: LED replacement lamps compatible with fluorescent ballasts, and LED retrofit kits. LED retrofit kits require the replacement of the fluorescent ballast with an LED driver (referred to as external driver), or bypassing the fluorescent ballast if the LED has in internal driver. Another option is the replacement of the whole luminaire with an LED luminaire, but this option was not considered in this project. No products from the LED retrofit kit category were found to meet the above stated desired characteristics. From the ballast‐compatible category, two product series were found to meet the above stated desired characteristics: Philips InstantFit LED T8, and Osram Sylvania SubstiTUBE LED T8. Not all lamps from these series necessarily meet the above stated desired characteristics, as the system power depends on the ballast used with the LED lamps. While some combinations of low ballast factor ballasts with higher power LEDs can also provide a suitable solution, the combinations further analyzed in this project are only those that involve normal ballast factor ballasts, as those have the highest potential for an easy installation without having to replace the existing ballast. Table 1 shows the products that meet the above stated desired characteristics when operated on a normal ballast factor ballast. Table 1. Products that meet the above stated desired characteristics when operated on a normal ballast factor ballast. The data in the table is from the manufacturers’ specifications. Product series Product number, color temperature System power per lamp 453589, 3000 K 453597, 3500 K Philips InstantFit LED 12T8/48 14.5 W 453605, 4000 K 453613, 5000 K 75084, 3000 K 75085, 3500 K Osram Sylvania SubstiTUBE LED12T8/L48 14.5 W 75086, 4100 K 75087, 5000 K The initial luminous flux specified by the manufacturers for all lamps listed in Table 1 when operated with a normal ballast factor is approximately 1600 lm (with minor variations based on the color temperature). This is significantly lower than the initial luminous flux for a typical T8 32W fluorescent lamp, which is about 2500 lm with a normal ballast factor. But because the light of a typical fluorescent lamp is not directional (light is evenly distributed around 360°), the lumens going up into the troffer are not well utilized. The Dillingham schools have replaced approximately 2000 of their T8 32W fluorescent lamps with 1600 lm Philips InstantFit LED lamps and haven’t perceived any decrease in illumination (they perceived some increase), but no data was collected to support that claim. Therefore, an experiment was set up at the UAF Bristol Bay Campus to verify the effect of the lamp replacement on the illumination levels. The experiment is described in the following section. Product testing A storage room at the UAF Bristol Bay Campus was used to test Philips InstantFit LED 12T8/48, 4000 K (product number 453605). The storage room is suitable for such testing because it has one luminaire and no windows. The luminaire has two lamps and both of them are connected to one Sylvania Quicktronic QHE2x32 T8/UNV ISN‐SC ballast (see Figure 1). Figure 1. Ballast used in the test This ballast is listed among compatible ballasts for the tested Philips InstantFit LED, as shown in the excerpt below. Table 2. Excerpt from Philips InstantFit ballast compatibility guide Three tests were performed, utilizing two lamps in each test. One test was with the existing T8 fluorescent lamps (Sylvania) of unknown age, one with the Philips InstantFit LEDs, and one with new T8 fluorescent lamps (SATCO) – see labels of all three lamps below. Each test utilized the same ballast (see Figure 1). Figure 2. Existing fluorescent lamp Figure 3. Philips LED InstantFit Figure 4. New fluorescent lamp In each test, after a stabilization period of 10 minutes, the system power (measured with a power meter on the input of the ballast) was recorded, as well as illumination measured with a light meter at several locations (see chart below). 50 Note: Watts shown in legend indicate measured system power (2 lamps + ballast). 45 43.1 39.9 40 Existing fluorescent, 55.2 W 34.9 35 InstantFit LED, 31.0 W candles] ‐ 30 New fluorescent, 55.1 W [foot 25 22.5 21.5 19.9 20 18 18.7 14.9 15.7 13.8 15 12.7 Illumination 10 7.3 5.9 6.3 5 0 Below luminaire Short‐axis wall, Short‐axis wall, Long‐axis wall, Long‐axis wall, (top of 24" stool) eye level (69" high) lamp level (93" high) eye level (69" high) lamp level (93" high) Figure 5. Results of power and illumination measurements for all three tests As shown in Figure 5, the measured power for both existing and new fluorescent lamp tests was about 27.6 W per lamp, which is in a good agreement with what is expected for a 32 W fluorescent lamp with a high efficiency ballast and normal ballast factor (0.88). The measured power for the Philips InstantFit LED was 15.5 W per lamp, which is in a reasonable agreement with the 14.5 W stated by the manufacturer and 14.2 W shown in the third‐party LM‐79 test report; the small difference is likely due to a different ballast used (LM‐79 report states Philips Advance ICN‐2P32‐N ballast). Replacing the 27.6 W fluorescent with the 15.5 W LED lamp represents the savings of about 12 W per lamp, or about 44% power savings. As also seen in Figure 5, the illumination for the Philips InstantFit LEDs is comparable to the illumination for the fluorescent lamps. In general, the illumination for the Philips InstantFIt LEDs was slightly (about 10%) higher than for the existing fluorescent and slightly lower (about 10%) than for the new fluorescent lamps, but the differences are not well perceivable by human eye, as demonstrated by pictures below. Figure 6. Existing fluorescent lamps Figure 7. Philips LED InstantFit lamps Figure 8. New fluorescent lamps In summary, the results of this test showed that replacing the two T8 fluorescent lamps in the given luminaire with two Philips InstantFit LED lamps resulted in approximately the same illumination levels and savings of about 12 W per lamp, or about 44% power savings. Economics The Philips InstantFit LED 12T8/48 lamp can be purchased for about $16 with free shipping. While no Osram Sylvania SubstiTUBE LED12T8/L48 was purchased in this project, from a quick internet search it appears that it can be purchased for a similar price. Therefore, it is assumed that the following calculations apply to both products. These payback calculations use $0.20/kWh, which is approximately the current price of electricity in Fairbanks, Alaska, but the same procedure (just different numbers) can be used to perform calculations for other locations. As shown earlier, power savings of about 12 W per lamp can be achieved by replacing a standard T8 32W fluorescent lamp with this LED. Assuming lamp operation of 10 hours per day, 365 days per year (which means 3650 hours per year), savings of 12 W * 3650 h, or 43800 Wh can be achieved annually. 43.8 kWh at $0.20/kWh corresponds to $8.76 in annual savings. Assuming the LED upgrade is done as a part of scheduled group relamping, no additional labor costs are accrued (savings achieved by not having to purchase new fluorescent lamps in the scheduled relamping are not accounted for in this analysis). With the initial cost of about $16 and annual savings of $8.76, the payback is less than 2 years. The payback would be less than 1 year in areas of rural Alaska where the price of electricity exceeds $0.40/kWh.
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