brickbat
Enlightened
Agreed. Further, unless you've compensated for the emissivity of the glass (which is less than 1), the readings are low.
Filament LED
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Agreed. Further, unless you've compensated for the emissivity of the glass (which is less than 1), the readings are low.
night.hoodie
Enlightened
Well, I, for one, don't need to hide my embarassingly childish amount of envy behind valid scientific criticism, and I'm not afraid or ashamed nor too proud to say... damn, nice thermal imager you have there. Thanks for posting the awesome thermal images. Does it work on cats?
Steve K
Flashlight Enthusiast
apologies for being pedantic, but my guess is that it is more accurate to say "air only transmits heat well if it moves". Conduction still works even if convection isn't being used, right?
PhotonWrangler
Flashaholic
PhotonWrangler
Flashaholic
It also occurred to me that if I were to remove the glass globe and re-image the filaments directly, it would still be inaccurate as the filaments would be exposed to cooling air currents in the room. The most accurate test would be to drill a small hole in the base of the bulb and snake in a thermistor, as electronupdate has done on several of his reviews.
Actually technically it is always moving .... even if a small bit. Non moving air is pretty terrible at heat transfer. Things get so hot that eventually you get movement and/or radiative becomes dominant.
Semiman
brickbat
Enlightened
The interesting ( to me, anyway) part with these 'filament LED lamps' is I've read (earlier in this thread) these lamps are helium-filled. Helium has a different heat transfer ability than air, and I recall it being a lot better.
If true, it's kinda everything good about Switch's design, without all the bad associated with a liquid-filled bulb...
on edit: Looks like OSRAM/Sylvania holds a relevant patent:
http://www.google.com/patents/US20040201990#legal-events
Which might be part of the reason these 'filament lamps' seem to be curiously absent from the US market...
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PhotonWrangler
Flashaholic
Interesting. If they're helium filled, it seems they would light up with a peach colored glow in the presence of a strong RF field. This could be a means of verifying the gas used.
brickbat
Enlightened
Sure, or suck out the fill gas and see if you talk like a chipmunk 
Steve K
Flashlight Enthusiast
very interesting and a bit tempting... did I mention that I work in the EMC field and spend a lot of time with high power RF amplifiers?
Any idea what field strength is required? Our lab generally tests around 140V/m.
oh.. we also have RF shielded cameras in the test chamber. It's better than standing around in a 140V/m field while waiting for a bulb to glow (or monitoring more business related things)
degarb
Flashlight Enthusiast
It occurs to me that a helium filled design, will likely make it more fragile and prone to factory defects. The choice of reliable brand may be important. Greenbuildingadvisor article alludes to a percentage of initial failures.
The pattent thing is interesting. I wonder if Big Brother will step in to identify and help negotiate a settlement, as to part of the national effort toward energy independence, since 75 lpw to 105 is nearly a 50% improvement on a fledgling technology.
The pattent thing is interesting. I wonder if Big Brother will step in to identify and help negotiate a settlement, as to part of the national effort toward energy independence, since 75 lpw to 105 is nearly a 50% improvement on a fledgling technology.
A good portion of that "efficiency" is from a design that has no power factor correction, is not dimmable, and has brutal headache inducing flicker. Making a 105 lumen/watt bulb today is pretty easy when you throw away all the typical parameters that define a good bulb.
Semiman
brickbat
Enlightened
What's your basis for the flicker condemnation? I thought electronupdate couldn't measure any flicker...
brickbat
Enlightened
For other readers not familiar with power factor, could you explain why they should care? (I'm talking about average residential users here...)
Well, just in case here's a simple explanation of what power factor is.
To put it simply: Low power factor means that you will have current surging back and forth over the transmission lines that aren't doing anything useful. Since transmission lines are resistive by nature, that extra current will be mostly lost as heat. So basically the power company will be generating power that will get wasted. This will increase everyone's bills.
Now if it's just one or two bulbs in the neighborhood with a poor power factor, that's not a big deal. Those won't even register. If every house in a city uses them though, that could create current surges large enough to start wasting a lot of energy. So while it's not really important from a residential perspective, it's very important from a power company or grid perspective.
I'm not familiar with the electric code or UL criteria, but I'm fairly sure that almost all consumer electronics and appliances must have a reasonable power factor to be approved. So things like your air conditioner, refrigerator, etc all have power factor correction so that the power factor is very close to 1. All of the normal retail LED/CFL bulbs I've seen for sale have a power factor of 0.9 or higher. I've only seen the filament bulbs with low power factor being sold on ebay or through small importers (i.e. not approved by any US entity).
brickbat
Enlightened
Yep - that's the basic principle alright. I'd just like to see it put in perspective with real numbers.
And, if this is really true, it seems like we trade good PF for efficiency - so what's the point?
And, if this is really true, it seems like we trade good PF for efficiency - so what's the point?
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idleprocess
Flashaholic
Industrial customers are usually billed for low PF in addition to MWH consumed; as such it makes sense for them to balance the costs of better power factor equipment against their own PF correction gear at the utility connection point.
For residential customers, the utility has typically dealt with poor power factor by installing huge PF correction gear at the substation, however with the roll out of residential smart meters they now have the potential to bill residential customers for low PF. So soon enough it may become relevant to you as well.
Here's a really good article that gets into the meat of it.
You are also not really changing the efficiency that much for the power factor correction. You are trading off other aspects like flicker though.
