Posted by nicksanspam on July 14, 2006, 8:40 am
This morning I put two $20 Kill-a-Watt meters on two power strips with
a 100 W bulb screwed into one plug socket 80 cm from a "100 W equivalent"
23 W 10,000-hour Commercial Electric compact fluorescent with a 9-year
guarantee ($8.97 for 4 from Home Depot) and compared the outputs with
a Bunsen grease-spot photometer (a drop of oil on a piece of white paper :-)
Robert Bunsen (1811-1899) also invented the Bunsen burner. He was known as
an inept experimentalist with radical theories who isolated a foul-smelling
compound which he named cacodyl oxide and a whole series of related compounds
which turned out to be highly explosive. At one point, Bunsen accidentally
blew up his lab and was laid up in bed for a long time.
The grease spot disappeared (indicating equal illumination on both sides) when
the paper was 42.4 cm from the incandescent bulb, so it had (42.4/(80-42.4))^2
= 1.27 times the CF light output. After a minute or so, the 100 watt bulb
consumption dropped from 100 to 99 watts and the CF rose from 22 to 24, so
the CF was 99/(1.27x24) = 3.24 times more efficient, with 3.24 times more
lumens per watt.
After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot) used
35 watts and made the spot disappear 36.2 cm from the 100 W bulb when
it drew 98 watts, so it was (36.2/(80-36.2))^2 = 0.683 times brighter
than the CF, which was 98/(0.683x35) = 4.10 times more efficient.
Nick
Posted by Stubby on July 14, 2006, 9:07 am
Nice experiment! Thanks.
nicksanspam@ece.villanova.edu wrote:
> This morning I put two $20 Kill-a-Watt meters on two power strips with
> a 100 W bulb screwed into one plug socket 80 cm from a "100 W equivalent"
> 23 W 10,000-hour Commercial Electric compact fluorescent with a 9-year
> guarantee ($8.97 for 4 from Home Depot) and compared the outputs with
> a Bunsen grease-spot photometer (a drop of oil on a piece of white paper :-)
>
> Robert Bunsen (1811-1899) also invented the Bunsen burner. He was known as
> an inept experimentalist with radical theories who isolated a foul-smelling
> compound which he named cacodyl oxide and a whole series of related compounds
> which turned out to be highly explosive. At one point, Bunsen accidentally
> blew up his lab and was laid up in bed for a long time.
>
> The grease spot disappeared (indicating equal illumination on both sides) when
> the paper was 42.4 cm from the incandescent bulb, so it had (42.4/(80-42.4))^2
> = 1.27 times the CF light output. After a minute or so, the 100 watt bulb
> consumption dropped from 100 to 99 watts and the CF rose from 22 to 24, so
> the CF was 99/(1.27x24) = 3.24 times more efficient, with 3.24 times more
> lumens per watt.
>
> After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot) used
> 35 watts and made the spot disappear 36.2 cm from the 100 W bulb when
> it drew 98 watts, so it was (36.2/(80-36.2))^2 = 0.683 times brighter
> than the CF, which was 98/(0.683x35) = 4.10 times more efficient.
>
> Nick
>
Posted by Joseph Meehan on July 14, 2006, 9:28 am
nicksanspam@ece.villanova.edu wrote:
> This morning I put two $20 Kill-a-Watt meters on two power strips with
> a 100 W bulb screwed into one plug socket 80 cm from a "100 W
> equivalent" 23 W 10,000-hour Commercial Electric compact fluorescent
> with a 9-year guarantee ($8.97 for 4 from Home Depot) and compared
> the outputs with
> a Bunsen grease-spot photometer (a drop of oil on a piece of white
> paper :-)
> Robert Bunsen (1811-1899) also invented the Bunsen burner. He was
> known as
> an inept experimentalist with radical theories who isolated a
> foul-smelling compound which he named cacodyl oxide and a whole
> series of related compounds which turned out to be highly explosive.
> At one point, Bunsen accidentally blew up his lab and was laid up in
> bed for a long time.
> The grease spot disappeared (indicating equal illumination on both
> sides) when the paper was 42.4 cm from the incandescent bulb, so it
> had (42.4/(80-42.4))^2 = 1.27 times the CF light output. After a
> minute or so, the 100 watt bulb consumption dropped from 100 to 99
> watts and the CF rose from 22 to 24, so the CF was 99/(1.27x24) =
> 3.24 times more efficient, with 3.24 times more lumens per watt.
> After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot)
> used 35 watts and made the spot disappear 36.2 cm from the 100 W bulb
> when
> it drew 98 watts, so it was (36.2/(80-36.2))^2 = 0.683 times brighter
> than the CF, which was 98/(0.683x35) = 4.10 times more efficient.
> Nick
Good Job.
--
Joseph Meehan
Dia duit
Posted by Harry Chickpea on July 14, 2006, 9:58 am
nicksanspam@ece.villanova.edu wrote:
>This morning I put two $20 Kill-a-Watt meters on two power strips with
>a 100 W bulb screwed into one plug socket 80 cm from a "100 W equivalent"
>23 W 10,000-hour Commercial Electric compact fluorescent with a 9-year
>guarantee ($8.97 for 4 from Home Depot) and compared the outputs with
>a Bunsen grease-spot photometer (a drop of oil on a piece of white paper :-)
>Robert Bunsen (1811-1899) also invented the Bunsen burner. He was known as
>an inept experimentalist with radical theories who isolated a foul-smelling
>compound which he named cacodyl oxide and a whole series of related compounds
>which turned out to be highly explosive. At one point, Bunsen accidentally
>blew up his lab and was laid up in bed for a long time.
>The grease spot disappeared (indicating equal illumination on both sides) when
>the paper was 42.4 cm from the incandescent bulb, so it had (42.4/(80-42.4))^2
>= 1.27 times the CF light output. After a minute or so, the 100 watt bulb
>consumption dropped from 100 to 99 watts and the CF rose from 22 to 24, so
>the CF was 99/(1.27x24) = 3.24 times more efficient, with 3.24 times more
>lumens per watt.
>After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot) used
>35 watts and made the spot disappear 36.2 cm from the 100 W bulb when
>it drew 98 watts, so it was (36.2/(80-36.2))^2 = 0.683 times brighter
>than the CF, which was 98/(0.683x35) = 4.10 times more efficient.
>Nick
Nick, this is much more useful than a lot of your pie in the sky
calculations. Well done.
BTW, if the CFs were in a pack of four, did you test for variations?
That would be useful information as well.
Also, did you check the lumen output either by using a standard
candle, or a photometer (perhaps one in a camera?). Incandescent
lamps dim with age, so using an older 100 watt lamp might have
affected the results.
Posted by Derek Broughton on July 14, 2006, 3:08 pm
Harry Chickpea wrote:
> nicksanspam@ece.villanova.edu wrote:
>
>>Robert Bunsen (1811-1899) also invented the Bunsen burner. He was known as
>>an inept experimentalist with radical theories who isolated a
>>foul-smelling compound which he named cacodyl oxide and a whole series of
>>related compounds which turned out to be highly explosive. At one point,
>>Bunsen accidentally blew up his lab and was laid up in bed for a long
>>time.
This part may not have been vital - but it's the sort of thing I love to
know :-)
>>so the [23W] CF was 99/(1.27x24) = 3.24 times more efficient,
>>with 3.24 times more lumens per watt.
>>
>>After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot) used
>>35 watts and made the spot disappear 36.2 cm from the 100 W bulb when
>>it drew 98 watts, so it was (36.2/(80-36.2))^2 = 0.683 times brighter
>>than the CF, which was 98/(0.683x35) = 4.10 times more efficient.
>
> Nick, this is much more useful than a lot of your pie in the sky
> calculations. Well done.
I'm sure many of his calculations are useful to people who want to be
frugal - but I'm stunned that Nick managed this without a line of Basic
code :-)
The numbers are interesting - the 23W CF really was approximately 23W but
the 42W CF was much less. I'm not at all surprised that the 23W bulbs
really aren't 100W-equivalent - typical marketing hype - but those results
are acceptable to me.
> Also, did you check the lumen output either by using a standard
> candle, or a photometer (perhaps one in a camera?). Incandescent
> lamps dim with age, so using an older 100 watt lamp might have
> affected the results.
Don't CFs dim with age? Can we then expect the relative efficiency to
improve over time?
--
derek
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> a 100 W bulb screwed into one plug socket 80 cm from a "100 W equivalent"
> 23 W 10,000-hour Commercial Electric compact fluorescent with a 9-year
> guarantee ($8.97 for 4 from Home Depot) and compared the outputs with
> a Bunsen grease-spot photometer (a drop of oil on a piece of white paper :-)
>
> Robert Bunsen (1811-1899) also invented the Bunsen burner. He was known as
> an inept experimentalist with radical theories who isolated a foul-smelling
> compound which he named cacodyl oxide and a whole series of related compounds
> which turned out to be highly explosive. At one point, Bunsen accidentally
> blew up his lab and was laid up in bed for a long time.
>
> The grease spot disappeared (indicating equal illumination on both sides) when
> the paper was 42.4 cm from the incandescent bulb, so it had (42.4/(80-42.4))^2
> = 1.27 times the CF light output. After a minute or so, the 100 watt bulb
> consumption dropped from 100 to 99 watts and the CF rose from 22 to 24, so
> the CF was 99/(1.27x24) = 3.24 times more efficient, with 3.24 times more
> lumens per watt.
>
> After warmup, a "150 W equivalent" 42 W CF ($5.97 from Home Depot) used
> 35 watts and made the spot disappear 36.2 cm from the 100 W bulb when
> it drew 98 watts, so it was (36.2/(80-36.2))^2 = 0.683 times brighter
> than the CF, which was 98/(0.683x35) = 4.10 times more efficient.
>
> Nick
>