Re: The Rebirth of the Incandescent Lamp

On Mon, 06 Jul 2009 14:13:01 -0400, Victor Roberts
<xxx@xxxxxxxxxxxxxxxxxxxxx> wrote:

On Mon, 6 Jul 2009 17:08:14 +0000 (UTC), don@xxxxxxxxxxxxxx
(Don Klipstein) wrote:

In <svp355hagl603pqj2edsa218skj78ek5dq@xxxxxxx>, Victor Roberts wrote:

News article in today's New York Times.

http://www.nytimes.com/2009/07/06/business/energy-environment/
06bulbs.html?_r=1&hp

We've all seen this before. The potential gains are
certainly there for both IR reflective coatings and
spectrally selective filaments, but no one has been able to
tap those gains in over 25 years of work.

It will be interesting to see if lamps can be made that meet
the new performance targets.

As the article says, Philips Halogena Energy Saver is already available
at Home Depot and Amazon. The 40 watt one meets the 2012/2014 energy
efficient requirements. Depending on who I listen to, the 70 watt one
either meets these or falls only slightly short.

I had forgotten about the Philips lamps, which are quite
good, at least for incandescent lamps. I didn't realize
that the efficacy goals were set so low. Lamps drawing no
more than 43 watts must produce 750 to 1049 lumens. So the
efficacy range is 18.75 to 26.225 lm/W, and the Philips 40
watt comes in at 20 lm/W.

The 70 watt Halogena is rated for 1600 lumens, which means
it falls into the 72 watt maximum wattage category, and
meets it based on the published specifications. Lamps
drawing no more than 72 watts must produce at least 1490
lumens, but need not produce more than 2600.

These lumen targets are all for 1000 hours, so the Philips
lamps at 3000 hours are significantly better products.

This data is from the Energy Independence and Security Act
of 2007. These are the same limits that appear to be in the
2009 energy bill, but I don't have a final copy yet.

A small bit of additional info. Both the 2007 and 2009
energy bills require that general service lamps have an
efficacy of 45 lm/W or greater by 2020. The way this is
stated is that the Secretary of Energy is to set new
standards by 2020, but if he/she does not set a standard at
least as high as 45 lm/W, no lamps with an efficacy lower
than 45 lm/W will be allowed to be sold.

The Philips Halogena Energy Saver lamps do not meet this
goal.

As for "rapid developments" discussed in the Times article,
as far as I can determine, the Philips Halogena Energy Saver
lamps are basically the same halogen-IR incandescent
filament tubes we have had for decades in reflector lamps,
but now put in A-line type envelopes. (They may be lower
pressure versions of the filament tubes to reduce the risk
of explosion, but that lowers the efficacy for a given lamp
life; it does not raise it.) An additional small gain is
possible by reducing the filament supply voltage with a
diode or something more sophisticated, but this is also an
old idea that works, but has never been put in place due to
high cost and, for the case of the diode, power line current
distortion.

To be clear, both IR reflecting films and filament
modification have the theoretical potential for huge
increases in efficacy. There is no fundamental reason (e.g.
no violation of the laws of energy conservation) that
prevents either of these tools from being used to make
incandescent lamps that produce "white" light with an
efficacy of 200 lm/W. The efficacy of incandescent lamps
produced with either IR reflecting films or modified
emissivity filaments has always been limited by practical
limitations of the materials used for both, and geometrical
issues with the IR films. It will be interesting to see if
more progress can be made in the next few years to resolve
these decades old issues.


--
Vic Roberts
http://www.RobertsResearchInc.com
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