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How about explaining that statement?
by throwthrowuknow 2y ago
How about explaining that statement?
- exitb 2y agoThe bulbs emit more lumens per watt when the filament runs hotter, but it lowers its expected life span. Using a bulb with a longer life span wouldn't necessarily save you money, as you would need to use more electricity to get the same amount of light.
- petra 2y agoTo What does this wasted electricity turns to, if not heat?
- deleted 2y ago[deleted]
- bonzini 2y agoEfficiency is lower in a colder filament because more of the radiation is in the infrared for a given wattage. So you get more heat for an equal amount of visible light. Here is an example with plausible (but not real) numbers. Higher current (hot filament): 1000 lumen, 100 W, 10 lumen/watt, 1000 hour lifetime Lower current (colder filament): 333 lumen, 50 W, 6.66 lumen/watt, 3000 hour lifetime. To emit 1000 lumen for 3000 hours you'll use 3 of the former lightbulbs (one after another) and consume 300 kWh, 100 per lightbulb. And you'll also use 3 of the latter lightbulbs (in parallel) but you'll spend 450 kWh, 150 per lightbulb.
- ssl-3 2y agoHeat. Just heat. Remember, an incandescent light bulb is primarily a heater -- even in the very best case, most of the energy input becomes heat. This heater just happens to be so hot that it glows white and produces usable light.
- calfuris 2y agoAll of the electricity turns to heat in any case. The problem is the nature of incandescence. Incandescent filaments are black-body radiators. The spectrum of black body radiation changes with temperature[1], so filaments that run hotter emit a larger proportion of their energy in the visible spectrum. [1] https://upload.wikimedia.org/wikipedia/commons/1/19/Black_body.svg https://upload.wikimedia.org/wikipedia/commons/1/19/Black_bo...