D
Dan Lanciani
| On 22 Jun 2008 17:16:51 GMT, ddl@danlan.*com (Dan Lanciani) wrote:
|
| >|
| >|
| >| > In the past few years I've noticed that the commodity F40 and F96 tubes
| >| > at the home centers are once again 40W and 75W respectively, so I assume
| >| > they all now qualify for the good color rendering (or other) exemption
| >| > from the requirements. (Or are they lying about the wattage?)
| >| >
| >| > Dan Lanciani
| >| > ddl@danlan.*com
| >|
| >|
| >| Trichromatic phosphor blends are much more common these days and a lot
| >| cheaper than they used to be, so you can easily get 40W high CRI lamps.
| >
| >And 75W F96 tubes, though they cost a little more than the dirt cheap CW
| >versions did. I guess this is great if you like a high color rendering
| >index, but I'm still not clear on how it ultimately helped with energy
| >conservation or efficiency. Now if they had gone on to produce 34W F40
| >and 60W F96 tubes that put out as much light as the older 40W and 75W
| >versions I could see the justification for the higer costs, ballast
| >replacements, and such in the meantime. But as it is, aren't we pretty
| >much back where we started (from an energy usage point of view)?
| >
| > Dan Lanciani
| > ddl@danlan.*com
|
|
| Hi Dan,
|
| Twenty or thirty years ago, a conventional two-tube F96T12 fixture
| would draw about 180-watts. Today, with 60-watt lamps and energy
| saving magnetic ballasts, that number falls closer to 135 or
| 140-watts, so there's been at least some improvement.
I get kind of confused when several variables change at once.
Assume that I use the same ballasts I was using 20-30 years ago
and also assume that I don't like the lower illumination from the
60W tubes so I use the current more expensive 75W tubes. (Both
assumptions happen to reflect reality. How does my energy usage
today compare to my usage when I could get the cheap 75W cool white
tubes?
| In terms of operating efficacy, a 75-watt Sylvania F96T12/D41/ECO
| (4,100K/70 CRI) is rated at 6,420 initial lumens and powered by a
| standard magnetic-core ballast (0.88 BF), we obtain about 63 lumens
| from each watt. A 60-watt Sylvania F96T12/D41/SS/ECO (4,100K/70 CRI)
| at 5,600 initial lumens and driven by a newer energy saving magnetic
| ballast would bump that up to perhaps 71 or 72 lumens per watt.
Can I get energy saving magnetic ballasts to drive 75W tubes at higher
efficiency or do they depend on using the 60W tubes?
Dan Lanciani
ddl@danlan.*com
|
| >|
| >|
| >| > In the past few years I've noticed that the commodity F40 and F96 tubes
| >| > at the home centers are once again 40W and 75W respectively, so I assume
| >| > they all now qualify for the good color rendering (or other) exemption
| >| > from the requirements. (Or are they lying about the wattage?)
| >| >
| >| > Dan Lanciani
| >| > ddl@danlan.*com
| >|
| >|
| >| Trichromatic phosphor blends are much more common these days and a lot
| >| cheaper than they used to be, so you can easily get 40W high CRI lamps.
| >
| >And 75W F96 tubes, though they cost a little more than the dirt cheap CW
| >versions did. I guess this is great if you like a high color rendering
| >index, but I'm still not clear on how it ultimately helped with energy
| >conservation or efficiency. Now if they had gone on to produce 34W F40
| >and 60W F96 tubes that put out as much light as the older 40W and 75W
| >versions I could see the justification for the higer costs, ballast
| >replacements, and such in the meantime. But as it is, aren't we pretty
| >much back where we started (from an energy usage point of view)?
| >
| > Dan Lanciani
| > ddl@danlan.*com
|
|
| Hi Dan,
|
| Twenty or thirty years ago, a conventional two-tube F96T12 fixture
| would draw about 180-watts. Today, with 60-watt lamps and energy
| saving magnetic ballasts, that number falls closer to 135 or
| 140-watts, so there's been at least some improvement.
I get kind of confused when several variables change at once.
Assume that I use the same ballasts I was using 20-30 years ago
and also assume that I don't like the lower illumination from the
60W tubes so I use the current more expensive 75W tubes. (Both
assumptions happen to reflect reality. How does my energy usage
today compare to my usage when I could get the cheap 75W cool white
tubes?
| In terms of operating efficacy, a 75-watt Sylvania F96T12/D41/ECO
| (4,100K/70 CRI) is rated at 6,420 initial lumens and powered by a
| standard magnetic-core ballast (0.88 BF), we obtain about 63 lumens
| from each watt. A 60-watt Sylvania F96T12/D41/SS/ECO (4,100K/70 CRI)
| at 5,600 initial lumens and driven by a newer energy saving magnetic
| ballast would bump that up to perhaps 71 or 72 lumens per watt.
Can I get energy saving magnetic ballasts to drive 75W tubes at higher
efficiency or do they depend on using the 60W tubes?
Dan Lanciani
ddl@danlan.*com