Re: Starving people refuse to eat food aid
Richard Casady
<dsch...@panix.com> wrote:
>In alt.folklore.urban "Sea Wasp (Ryk E. Spoor)" <sea...@sgeinc.invalid.com> wrote:
>:David Scheidt wrote:
>:> In alt.folklore.urban Wayne Throop <thr...@sheol.org> wrote:
>:> :: David Scheidt <dsch...@panix.com>
>:> :: Lets assume he's using 100 watt bulbs. So he's got three of them,
>:> :: each consumin 33.33 W, still 100 W. However, he's only going to get
>:> :: about as much light out of them as he would a 50 W bulb. So, over the
>:> :: course of the 1000 hours that a 50W bulb would last, he's wasted 50
>:> :: kW hours. 50 kWh costs me about 5 bucks. A plain old incandescent
>:> :: bulb costs a lot less than a buck.
>:>
>:> :Nnnnnno, all *together* they are consuming 33.33 W. E=V^2/R,
>:> :so if he's using three bulbs, the whole assembly has tripple
>:> :the resistance (as a lousy approximation; actually the resistance
>:> :is temperature dependent...). Or alternatively, looking at it from
>:> :the viewpoint of an individual pulb, each bulb sees 1/3 the voltage
>:> :drop, and is therefore consuming 1/9 of the power (again, modulo the
>:> :issue of resistance varying with temperature).
>:>
>:> Duh. I know that. Really. That only makes things worse though.
>:> Bulb light output is dependent on fillament temperature.
The output varies with the fourth power of the temperature. The peak
wavelength varies directly with the temperature. Three bulbs will have
57% of the temperature as one.
>:> applied voltage to a bulb is decreased, its filament temperature goes
>:> down. As the temperature goes down, more and more of the power
>:> radiated is useless heat.
>
>: Keith LIKES heat. It's not wasted.
>
>: And as I pointed out, the "wasted" energy wouldn't even pay for the
>:replacement bulbs he'd have needed over 36 years.
>
>Yes. it would He's getting, maybe, if he's lucky, 4 or 5 lumens per
>watt out of his bulbs. We'll call it 150 lumens. 150 lumens can be
>had from a 15 W bulb. he's wasting 18 watts. 18 kW hours cost about
>$1.8. A 15 watt bulb costs less than buck.
>
>running bulbs at less than their rated voltage is dumb, if what you're
>doing it for is to save money.
You run them low volt to extent the life when it is difficult to
change the lamps. Such as needing a bucket truck which you don't have.
Casady