On Fri, 13 Dec 2013 10:39:57 -0800, (David
Platt) wrote:

According to one U.S. Government document I read yesterday, CFLs which
have the Energy Star labeling are required to work equally well in any
orientation, *unless* the manufacturer specifically labels them
otherwise.

I think that appeared about 8-10 years ago, when someone figured out
how to equally distribute the mercury in the bulb. Prior to that, the
orientation had a big effect on output and color:
http://www.lrc.rpi.edu/programs/nlpip/lightinganswers/hwcfl/HWCFL-lamp-orientation.asp
http://eetd.lbl.gov/newsletter/cbs_nl/nl01/cbs-nl1-notcool.html

Wouldn't surprise me if this isn't very well enforced, though. I've
had some fairly poor-lifetime results from some of the cheapie CFLs,
no matter what orientation we use them in. And, it's quite
disconcerting when their failure mode involves a hot base and
nasty-smelling smoke. :-(

Agreed. I've also done a post mortem on the CFL base and found fried
components, mostly bulging electrolytic caps, and overheated PCB's.
However, I've only torn apart a few, all of which came from the same
source (dollar store).

Has anybody come across a good source for good LED-based ceiling
fixtures? Seems to me that the real "win" for LED lighting isn't in
"screw-in" replacement for existing incandescent bulbs (heat build-up,
less-than-wonderful light dispersion) but for ceiling-mountable
fixtures with a broader array of LEDs and a diffuser. This would
spread out the heat of the LEDs into a much larger
radiating/convection area and reduce the "bright points of light"
effect.

You might be able to build something out of LED lighting strips.
www.ebay.com/sch/i.html?_nkw=led lighting strip
http://www.superbrightleds.com/cat/flexible-strips-and-bars/
Glue them to an aluminum plate. Add a diffuser and dimmer.
One of my neighbors built one for a customer and made a few big
mistakes. LED's are more efficient, but they still put out plenty of
heat. There's a fairly large air gap between a CFL or incandescent
bulb and anything that might catch fire. Not so with the stick on LED
lights. The ceiling (material unknown) got rather toasty hot. You'll
need an air gap, and some air flow between the heatsink and ceiling.

If I could find a nice-looking panel 18"-24" square, which could
radiate the equivalent of 5000+ lumens of warm-white (e.g. three
100-watt incandescent bulbs or more) I'd replace the old three-bulb
ceiling fixture in our family room like a shot. We've got CFLs in it,
but they're so bulky I had to remove the diffuser... doesn't look
wonderful.

Time for some math. Skimming through the available white LED strips,
and picking this one as a likely candidate (because they have specs):
http://www.superbrightleds.com/cat/flexible-strips-and-bars/
For warm white (3000K), one foot of LED's produces 115 lm/ft, and
burns 1.1 watts of power. To obtain 5000 lumens, you'll need
5000 lm / 115 lm/ft = 44 ft
of LED strips. LED's per foot is:
12 in / 0.651 inch_spacing = 18.4 LED's/ft
for a total of:
18.4 LED's/ft * 44ft = 811 LED's
Power consumption would be:
1.1 watts/ft * 44ft = 48.4 watts
Assuming staggered adjacent rows and 0.5" spacing between strips, and
0.651" between LED's along each strip, the size of the array would be
roughly 18" x 15" or 30 strips, 18" long, spaced 1/2" apart. Yeah, it
would fit and probably work.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558