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

Nice experiment! Thanks.

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

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

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.

Harry Chickpea wrote:

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

In Derek Broughton writes:
[ various snippages ]

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.

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?

- also, keep in mind that the lumen ratings for
traditional fluorescents are the initial output,
but... it's _after_ 100 hours of burn in.

When first lit, they tend to be a modest amount
brighter than spec. There's a rapid 'burn off" (for
want of a better description, and then, at a nominal 100 hrs,
they stabilize (to a slight long term downward slope).

So if you used brand new CFLs, you're seeing a bit
of an artificial peaking...


--
__________________________________________________ ___
Knowledge may be power, but communications is the key

[to foil spammers, my address has been double rot-13 encoded]

Derek Broughton wrote:

... the 23W CF really was approximately 23W but the 42W CF was much less.

Surprising...

... did you check the lumen output either by using a standard candle,
or a photometer (perhaps one in a camera?).

No. I'm not sure how standard standard candles are.
I've used CSA standard fingers...

Don't CFs dim with age?

I believe they do.

Can we then expect the relative efficiency to improve over time?

I doubt that. Don Klipstein might help here.

Nick

Can we then expect the relative efficiency to improve over time?


I doubt that. Don Klipstein might help here.

Nick


I think they dim cause the mercury sticks somewhere or soemthing, but no
current drop I would think

In article ,
Derek Broughton wrote:

Don't CFs dim with age? Can we then expect the relative efficiency to
improve over time?
--
derek

No, not typically. Very few Gas Discharge lights dim with age unless
the excitation voltage drops significantly. The Gas doesn't wear out,
but the electronics that fire the voltage may.....

No, again not typically. Very few electronic systems get better as
the components age, so efficency should slowly drop a bit with age....

You wrote:

Derek Broughton wrote:

Don't CFs dim with age? Can we then expect the relative efficiency to
improve over time?

No, not typically. Very few Gas Discharge lights dim with age...

IIRC, most do.

Nick

wrote in message
...
You wrote:

Derek Broughton wrote:

Don't CFs dim with age? Can we then expect the relative efficiency to
improve over time?

No, not typically. Very few Gas Discharge lights dim with age...

IIRC, most do.

In my experience they do.

Mary

"You" wrote in message
...
In article ,
Derek Broughton wrote:

Don't CFs dim with age? Can we then expect the relative efficiency to
improve over time?
--
derek

No, not typically. Very few Gas Discharge lights dim with age unless
the excitation voltage drops significantly. The Gas doesn't wear out,
but the electronics that fire the voltage may.....


snip

They why does my employer change out the fluorescent lighting about every 5
or 6 years even when they are all burning good? When they do, the rooms are
so much brighter. Makes a huge difference.




---
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Virus Database (VPS): 0628-5, 07/14/2006
Tested on: 7/15/2006 4:34:45 PM
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http://www.avast.com

C. Massey wrote:

They why does my employer change out the fluorescent lighting about every 5
or 6 years even when they are all burning good? When they do, the rooms are
so much brighter. Makes a huge difference.

The new fluorescent bulbs have a higher color temperature with more
blue light causing the perception of being much brighter.

--
Ron

You wrote:
In article ,
Derek Broughton wrote:

Don't CFs dim with age? Can we then expect the relative efficiency to
improve over time?
--
derek

No, not typically. Very few Gas Discharge lights dim with age unless
the excitation voltage drops significantly. The Gas doesn't wear out,
but the electronics that fire the voltage may.....

No, again not typically. Very few electronic systems get better as
the components age, so efficency should slowly drop a bit with age....

ALL lighting dims with use! It is called "Lamp Lumen Depreciation"
(LLD) by the pros and can be found in the detailed specifications from
the manufacturers.
Mostly in fluorescents the electrode loses some tungsten (those black
ends, just like incandescents) and there is some mercury loss as well.
Both degrade the starting and the arc, THAT causes less light.

Electronics is a whole other issue. As is dirt on the bulb and fixture.

It is useful to note that LLD is not related to when a lamp fails. This
is why some folks claim bulbs that have lasted extreme times, the
efficiency has gone to ****.

Other things to note:
1. All lamps should have a "lumen" rating on the package. This is the
actual amount of light as measured by more advanced technology than
eyeballing a dirty piece of paper.. It should also have the expected
life, in hours. Multiply the two. This is how much light you are buying
for the price of the bulb and the power.

Formula is as follows:
(Lumens (adjusted for LLD if you want get detailed) x Life) / (Watts x
Life x $) = true efficiency (lumens per dollar).
Note that you have to get your units right. Power is usually sold in
KWH = 1000 watts for one hour or one watt for 1000 hours. Also the lamp
life is an average statistic so it applies over large numbers of bulbs.
;-)

2. There are many kinds of incandescent bulbs. Soft White - IF - Clear
- colored - 130V -120V - "long life" - halogen - shatter resistant -
vibration resistant.... ALL have different light output.

3. CF's come in even more types and will vary widely by brand, model,
color, lot and even within a lot.

4. Heat, especially inside a fixture, can dramatically change a
fluorescent lamps efficiency. (Both too much and too little are
problems.) This is why CF's upside down in recessed fixtures tend to
fail quickly.

5. CF's are a softer, more diffuse light that will not be reflected
inside a fixture the same way as an incandescent will.

Richard Reid, LC
Luminous Views
Lighting Design for Home and Business

RickR wrote:

... All lamps should have a "lumen" rating on the package. This is the
actual amount of light as measured by more advanced technology than
eyeballing a dirty piece of paper.

But perhaps no more accurately. I've seen Bunsen photometers in modern
physics labs, mounted on optical benches, and so on.

Nick

Derek Broughton wrote:
Don't CFs dim with age?

Yes, they do, in fact their lifetime is based not on loss of
functionality, but on reaching some percentage of nominal output.

Can we then expect the relative efficiency to
improve over time?

No, that would make relative efficiency _drop_ over time.

wrote in message
...
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.

He might have been inept but his name has lasted longer than many who were
ept :-)

How many of his critics' inventions are still used?

Mary

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 :-)

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)
[...]
was 98/(0.683x35) = 4.10 times more efficient.

Many Thanks!

How did you measure 42.4cm from the bulb, or is that like R 3 aluminum
foil..........

m Ransley wrote:

How did you measure 42.4cm from the bulb...

I lined up the center of each bulb on the 0 and 80 cm marks on
a Craftsman 939675 8m/26' measuring tape, then moved the paper
along the tape until the grease spot disappeared at 42.4 cm.

Nick

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
//

Tut writes:

Nick, if you replace one of the lamps with a burning candle, you can
calculate the strength of the each lamp in candles vs lamp wattage.

E=C/d^2-------- C1/d1^2=C2/d2^2

whe E=foot-candles
C1= one candle
C2= candles of light source
d1= distance to oil drop for burning candle
d2= distance to oil drop of lamp under test

In article ,
says...
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)


I almost read that as meaning "the grease spot" that was left on
the floor where Robert Bunsen was standing at the moment of the
lab explosion.


--
Want Freebies?
http://www.TheFreeStuffList.com/
Check The Free Stuff List

wrote in message ...
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 :-)

Yeah, I've got some of those 100W equivalent, $8.97 bulbs, with a 9-year
guarantee too.

I don't need a grease-spot photometer to tell me they don't put out as
much light as a 100W bulb. My own eyes can tell me that. It takes a
150W equivalent to be a 100W equivalent, IMO.

The one in the hallway went out after about a year and a half to two
years. I don't know where my receipt is, so I guess I'm out a few bucks.

These CFL's sure are frugal. Just make sure you send in any rebates
and keep track of your receipts and the packing material for the
next 9 years.

Don

Don K wrote:

Yeah, I've got some of those 100W equivalent, $8.97 bulbs, with a 9-year
guarantee too.

I don't need a grease-spot photometer to tell me they don't put out as
much light as a 100W bulb...

It worked out to 79%, but still an energy bargain.

The one in the hallway went out after about a year and a half to two
years. I don't know where my receipt is, so I guess I'm out a few bucks.

Maybe not. These bulbs have a phone number (800) 378-6998 and a date code
V# xxxxx printed on the base. I called the number and gave them the code
and they sent me a new one, after one died.

Nick

"Don K" wrote in message
. ..
wrote in message
...
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
:-)

Yeah, I've got some of those 100W equivalent, $8.97 bulbs, with a 9-year
guarantee too.

I don't need a grease-spot photometer to tell me they don't put out as
much light as a 100W bulb. My own eyes can tell me that. It takes a
150W equivalent to be a 100W equivalent, IMO.

I think that too.

The one in the hallway went out after about a year and a half to two
years. I don't know where my receipt is, so I guess I'm out a few bucks.

These CFL's sure are frugal. Just make sure you send in any rebates
and keep track of your receipts and the packing material for the
next 9 years.

We pencil the installed date and the supplier on the item itself. We've only
twice had to return them and they've been replaced with no receipt and no
question.

Customer goodwill is important to stores. The items are cheap and it's
recognised that some will fail.

Mary

"Mary Fisher" wrote in message
t...

"Don K" wrote in message
. ..

The one in the hallway went out after about a year and a half to two
years. I don't know where my receipt is, so I guess I'm out a few bucks.

These CFL's sure are frugal. Just make sure you send in any rebates
and keep track of your receipts and the packing material for the
next 9 years.

We pencil the installed date and the supplier on the item itself. We've only twice had to return
them and they've been replaced with no receipt and no question.

Customer goodwill is important to stores. The items are cheap and it's recognised that some will
fail.

Mary

It's worth a try. I'll just take it back next trip to the 'depot.
Thanks

Don