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Monday, April 6, 2009

Utilities suffer from CFLs’ poor power factor

Apr 6 2009 6:00PM | Permalink |Comments (90) |

Every CFL light contains a small ac-dc power supply with reactive components in it that will affect the CFL’s power factor (PF) – that is, the load presented to the ac line. The closer the PF is to 1, the better. A load with low power factor (<.85) draws more current and is less efficient than a load with a high power factor for the same amount of useful power. The higher currents required by the lower PF devices mean increased energy lost in the grid due to such things as I²R losses. These power losses don’t show up directly on our electricity bill, but the utilities sure see the effects.

I put one of my home CFL bulbs on my Kill-O-Watt power meter recently and measured its power factor: It was .57. This is lousy. Although each CFL is only 13W, there are millions of them out there. Why no PF regulation, as there is of higher-power, but less ubiquitous devices?

I emailed Peter Banwell of the EnergyStar program and asked if EnergyStar was considering making minimum PF a requirement for Energy Star compliance. He replied, “We looked at this in detail several years ago and decided against it, though there are a couple of utilities that still support the idea. We may take this up in the future, as the market share grows, but right now it is still in the noise in terms of impacts.”

Coincidentally, after our email exchange I ran into Mike Grather of Luminaire Testing Laboratory. He recently ran a series of life-cycle and performance tests on a batch of 100 CFLs with various power ratings averaging approximately 20W each. They assumed a PF for the lights of at least .75 and sized the power supply at 3KVA. However, when they powered up the bank of CFLs, the 3KVA supply was inadequate. Grather checked the power factor for the CFLs and found they ranged from .45 to .50. Their “real” load was about twice that implied by their wattage.

CFLs are still an efficient form of household lighting, but their poor PF number is leaving money on the table. However, it’s clear that at about $2 each there’s not a lot of room for adding power factor correction circuitry. On the other hand, utilities are already going to great lengths to encourage consumers to switch to CFLs, including subsidizing the price of CFLs. I doubt that consumers would be interested in paying more for a feature that actually benefits the utility directly, not them. Perhaps utilities will start to subsidize high-power-factor CFLs, rather than the mediocre ones we can buy now.

Related entries in: Power Sources/Controllers |

Reader Comments

at 4/7/2009 1:14:50 AM, Tiamation said:
Power factor is not to blame for CF startup current at all! The draw is not quite so bad a design if you have a bunch of copper leading out to the lights, or a mix of loads. Nice reminder to just buy the tubes and do one''s own appropriate supply for major fixtures.

Banks of lights, though...did you put on The Philadelphia Experiment as local theatre, and inevitably need to green up all those glowing thyrodes?

at 4/7/2009 1:18:34 PM, Carl Spearow said:
When you say the real load is twice the wattage, that is confusing. The real power is the wattage. Perhaps what you meant to say is that the apparent power is twice the wattage. That doesn''t mean that CFLs actually use twice the rated power

at 4/7/2009 1:19:43 PM, Chris PE said:
Very interesting article. In most of the cases things greatly advertized are like that.It''s like ATX power supplies in PCs that draw a constant current with computer turned off.That was a revenge of utilities companies for initial switching power supplies which drastically reduced current demand of computers.Story pretty much repeats.I have a few of CFLs with a real balasts on them.They have been long discontinued - we know why,LOL.Not only longer lasting but also MUCH higher power factor if you know what else to connect to a circuit.I have a nice supply of incandescent lights and no CFL can replace them as living area lights.Many store were and are discontinuing very high quality "sun spectrum" bulbs made by Phillips and few others.Try one of those.Super reading light.As for CFLs , I have them only in "utility areas".My Kill-O-Watt meter will be busy tonight.Have a great evening and thank you for an interesting article.

at 4/7/2009 1:22:34 PM, Anonymous said:
The way I understand it is that while ratepayers may not be charged directly for low power factor devices, utilities still charge "line loss" fees to compensate for these losses, so end users are still paying, just as a whole instead of by account. And, when smart meters roll out,end users will be billed by the kVAh instead of the kWh, as before. At this point, assuming the issue gains attention and understanding, end users will likely have a problem with being charged, say, 30 VA for their "15 W" bulb.

at 4/7/2009 1:42:32 PM, DLD said:
It was not the startup that was in question, Tiamation. PF is an entirely diffent animal.

This is one of the two things I dislike about current CFLs and HB LEDs

at 4/7/2009 1:44:21 PM, DLD said:
bad PF and the inability to use common dimmers and light controls. About half of the circuits in my home are either dimmed or controlled. That means I can't use common CFLs or LEDs, even if I leave them at full brightness.

PF control can be added for pennies and dimmer ability for a couple of nickels. Come on guys! Give us a true replacement for the tungsten lamp!
(First post truncated.)

at 4/7/2009 2:03:43 PM, w17053 said:
Interesting PF info!
Sorry to be a broken record, but what do I use in my Oven and Refrigerator when my incandescent burns out?
I am weary about Mercury in / around my food. Congress never think about these things when they enact laws. I may have to risk stockpiling incandescent (and become a criminal) to keep my family safe.

at 4/7/2009 2:04:43 PM, PSPM to the rescue said:
Well come May 5th 2009 PureSpectrum (PSPM) will release there new CFL bulbs that will correct the problems with current CFL''s with having a much improved power factor and true dimmable capabilities.

at 4/7/2009 2:18:14 PM, SteveU said:
Power factor in the 21st century is not about input reactance, it’s about input non-linearity. See: IEC 61000-3-2 Harmonic Standards.

This is the same problem shared by any electronic device that must convert a sine wave power input into DC.
A typical CFL ballast is a voltage doubler rectifier and a pair of FETs in a totem pole driving the high frequency magnetics that make a low voltage for the filaments and high voltage across the tube ends. To keep the price down, there is no PF correction.

The PF issue is related to the dimming issue. A CFL that can operate in 120Hz /100Hz triac gated PWM pulses will not use bulk storage capacitors and exhibit a much improved PF, but this requires a switching oscillator that has virtually no startup time and operates over a wide voltage range. A similar problem exists with high current LED lights, although most low current LED arrays simply put all the LED in series and limit the input current with a capacitor.

at 4/7/2009 2:18:57 PM, PureSpectrum Lighting said:
There is going to be a new CFL on the market in the next 6 weeks that has a high PF (>0.95) and is dimmable. The best part, they will be comparable to the cost of current CFL''s on the market. AND like the old CFL''s that Chris PE mentioned in his post, they have an analog ballas that will last longer and is resistant to heat damage(the main reason for the current CFL''s short life span). Everyone will be hearing more about PureSpectrum Lighting.

at 4/7/2009 4:10:18 PM, Ampman said:
As interesting as PureSpectrum may sound, I''m at a loss to figure out how secondary emission can have black body emission. Philips stops all research on CFL and focuses on LED.

High PF for CFL has been touted in many PESC/APEC papers. I wonder if cost is what prevents their commercialization, as usual.

at 4/7/2009 4:35:11 PM, Mike said:
The power factor of the lamp is not the significant concern. Yes, utilities will have to compensate their distribution systems by adding capacitors to correct the power factor on their systems. This cost will be passed on to the consumer. However, that cost will pale in comparison to what the utilities must do to deal with the harmonic content of non-linear loads such as CFL's. They will have to replace major/costly equipment due to the heating effect of the harmonics on distribution transformers and conductors. Again, this cost will be passed on to customers. By the way, all of this harmonic energy will be wasted to the atmosphere thereby negating the cost/energy savings of the CFL's and similar devices.

at 4/7/2009 4:55:14 PM, Frans Pansier said:
A high value for the power factor is often believed to reduce losses. The contrary is true, however: adding an PFC will cause the application (CFL, or whatever else) to have more losses than before. These additional losses can be even higher than the additional losses in the grid. So for the sake of power saving one should not implement any PFC at all. And if at all, not better than 0.9: the higher the PF the higher the losses in the PFC circuit.

at 4/7/2009 5:10:11 PM, HAL said:
There are two ways that a load can have a low power factor. What we learned in school, whereby a reactance causes the current waveform to be out of phase with the voltage waveform, is one. Old style fluorescent fixtures with "magnetic" ballasts present this kind of load and the power factor can be really low - .25 and less is common. The other is the result of a simple bridge rectifier and capacitor filter - what one finds in nearly all CFLs with "electronic" ballasts. Such a circuit draws line current in brief, intense current pulses whose RMS value is many times the average value. This kind of load literally clips off the peaks of the line voltage waveform. The harmonics (3rd, 9th,...) also cause significant ground currents in 3-phase systems which have been known to cause neutral conductor burnout in large buildings.

My suggestion for improving the power factor of CFLs is to simply eliminate that big filter capacitor and give the high voltage inverter unfiltered DC. The only drawback I can think of is that the 120Hz flicker one gets with magnetic ballasts would also be present in the CFL light output.

at 4/7/2009 9:12:58 PM, M. Simon said:
Don''t leave out the fact that CFLs and all other types of constant power loads introduce negative resistance to the grid. i.e. as voltage goes up current goes down. Not good for stability of the grid.

at 4/7/2009 9:15:52 PM, JMS said:
To w17053:
The ban on incandescents will not affect special-purpose bulbs like the low-wattage devices that go in your oven and your refrigerator. So rest easy: your 7-bone roast will not be contaminated with mercury by your oven light. Now if only you had the same assurances about your kitchen chandelier...

at 4/7/2009 10:26:50 PM, An old EE with a PE said:
This story is based on hog wash! When one considers the VA base in the calculation - the power losses are neglible. A lighting circuit is fed from a 15A breaker and typically feeds 4 CFL''s or 90 W on a 1,800 W base.

at 4/7/2009 11:27:09 PM, Ajesh said:
It is not just the power factor. CFLs introduce harmonics which have worse effects than even power factor. Utilties shall face a real tough time in future managing that.

at 4/8/2009 5:49:39 AM, IPSguy said:
Utilities can easily correct adverse linear lagging power factor with capacitor bank PF correction, or in cases of very large lagging PF from motor loads (say a hot summer day where air conditioning is used), by connecting a gas turbine generator to the grid, turning off the turbine and over-exciting the generator field to turn it into a synchronous capacitor. What they cannot compensate for is the harmonic distortion caused by line rectification, high frequency oscillators and non-linear loads. CFL's fall in the latter category, and I suspect that the Kill-O-Watt meter frequency response is insufficient to show how really adverse the PF actually is.

at 4/8/2009 8:58:19 AM, Chris PE said:
My fellow engineers(?)
A real lack of basic knowledge of AC circuits shows in many comments.I would check Internet or my books before making a nonsense comment.Please show some knowledge instead speculating on sokmething that you have no idea about.Forget about house wiring , copper and connections.JUST THINK ABOUT BULB. Margety is describing a simple experiment that most of EE should understand while reading.Some comments are shameful.There is one VERY important about appliance bulbs. I hope that this nonsense with no more incandescent bulbs are juet a joke, because there are hundreds of applications (i.e. military) where CFs are ABSOLUTELY not acceptable.They cannot take vibration either.Looks like it will never happen that CFs will replace incandescent lightning.If it does than out political system is drifting from freedom...it would be like someone would come to your house and forbid you to use iron , blow dryer or curling iron.They take tons of energy more than all the bulbs trippled.

at 4/8/2009 9:33:28 AM, T. Shaw said:
Margery, you may try contacting a start up company, PureSpectrum (pink sheet PSPM), their cfl technology has the highest PF rating of any cfl's in the world, have the desired longevity and is dimmable. I am sure they would be pleased to provide their bulbs for Luminiare Testing Labs to evaluate their products.

at 4/8/2009 1:18:46 PM, Tom said:
So where does one get these PureSpectrum bulbs starting next month? I checked their web site and saw nothing about availability. All I saw was marketing hype and pretty language.

at 4/8/2009 1:21:15 PM, hk said:
Finally someone is thinking about their power factor. It is pretty obvious when you multiply their voltage and current ratings and end up with a number much higher than their power rating. CFLs have never been that good of an idea. Too much hype, too little light, too short a life in most applications, too expensive, too much mercury, among fit and functional problems in some applications. Why bother?

at 4/8/2009 1:29:09 PM, Railroad said:
RE the vibration issue with CFs: I have replaced the incandescent lights in my Sears garage door opener with CFs and they are lasting. I would get maybe a month from an incandescent before failure but the CFs have lasted over 4 months so far. As far as power factor is concerned the utility could do several things: 1. make the large appliances such as ACs and refrigerators have PF capacitors as standard equipment, 2. make electronic users such as TVs and computers have a minimum PF and 3. finally install additional switchable PF capacitors on the distribution lines. As far as the harmonics most likely the utiity distribution transformer in the back yard is crappy enough to filter out most of the noise.

I am a power EE.

at 4/8/2009 1:33:11 PM, Mot EE said:
Here's an older article which has a much better PF device.
www.paragonlighting.com/pdfs/Benefits%20of%20High%20Power%20Factor%20Ecospiral%20CFLs.pdf

at 4/8/2009 1:37:32 PM, w17053 said:
To JMS:
Thanks for the info. I''m glad to hear I can still buy oven and refrigerator bulbs. I hope they eliminate the law and let the consumer choose the product for the application, but you know congress.

at 4/8/2009 2:04:27 PM, mt said:
Interesting comments...Can anyone tell me if a lower power factor of a cfl causes an increase in the amount of radiation released from one of these bulbs?(ie. some bulbs change channels on tv''s) Or is this a different story...

at 4/8/2009 2:12:54 PM, GuyWhoReads said:
One key comment regarding consumer costs of CFLs has gone largely unrepeated: these things do not last as long as claimed. In particular, if they are oriented with the base above the light source and/or are in a confined/enclosed installation, they have a shorter life than incandescent bulbs. I have some that are in cooler locations (garage/basement) that have lasted surprisingly long, but use them in overhead ceiling lights for example and they go quickly. And of course, if you have not kept all the paperwork and packaging you can't use the "7 years" guarantee to get your $ back.

at 4/8/2009 5:05:00 PM, Jules said:
"In particular, if they are oriented with the base above the light source and/or are in a confined/enclosed installation, they have a shorter life than incandescent bulbs."

Utter rubbish. I've been using numerous CFLs in this arrangement for years, and have on average had them last longer than manufacturers labelling suggested they would. There may be some types that have trouble with it, but then there's the batch of incandescents I had last year that all blew out within 3 weeks of installation.

at 4/8/2009 6:14:59 PM, tarno_inz said:
The ultimate solution is to have DC distribution within the building. The balance of power loads is tipping towards DC over AC -- I wish I knew the numbers on this -- due to all of the electronics in a typical household. Yes, the power plug still uses AC, but, for example, a PC typically converts all of that to DC before using it to perform its designated function.
If the power to the house is the traditional AC, the AC-DC conversion is best done at the point of entry into the building. The advantage of a centralized location is that you can spend more to do the PFC correction or harmonic reduction and still come out ahead cost-wise rather than performing the conversion at the many loads.
Of course this is revolutionary for building wiring. Neither builders nor homeowners like change. Hence, this will not happen for many years. By the way, this also makes battery backup more efficient for personal computers.

at 4/8/2009 6:47:46 PM, Herb said:
With all this talk about power factor. What is my electric meter reading. Is it reading the 20 watts the bulb says or it it reading 40 or 60 watts.

at 4/8/2009 7:22:43 PM, consumer joe said:
Regarding lifespan and congress...

Surely congress knows that most people are just going to toss their dead CFLs in the trash, right? That makes it "someone else''s problem", pure political gold when it comes to elections but an environmental nightmare when reality intrudes.

at 4/8/2009 7:50:57 PM, spook said:
I am amazed at the misinformation posted in the comments here. Power factor is a measure of the phase difference between voltage and current. An inductive load like a motor stores energy in a magnetic field and this negative p.f. may be corrected with a compensating capacitive load. In a capacitive load, like the electronic ballast used in a CFC, energy is stored in an electric field and the positive p.f. would need an inductive load for compensation (not more capacitive).
Low p.f. loads, either capacitive or inductive, cause a power-source company increased generation and transmission costs because they still have to supply the peak current and voltage albeit at different moments due to the phase difference. It''s only the in-phase vectors (the resistive component) which is available to do work. In the case of florescence, this is to convert UV light into visible light and there are some losses (heat). If a reactive load has power-factor correction towards 1.0, then the same amount of work is done for smaller peak voltage and current supply. Lower current supply in particular means lower transmission losses and smaller diameter cables. The electronics in CFCs are not only capacitive, they are non-linear. This means that they chop into the supply with fast switching which creates a complex rapidly changing dynamic load. The effect of this is spikes of uncontrolled energy over a wide frequency range back into the circuit and free-space. In some cases, this is not acceptable. It''s true that a poor performing local distribution transformer would lose most of this line-noise as heat - in a sort of unintentional low-pass filter, but local problems could still be seen.
The amount of mercury in a CFC is actually quite tiny, but massive acceptance of the product would mean a big disposal problem, and perhaps a significant issue with p.f. although I suspect there is as much or more issue with -ve p.f. devices like computers. I agree that CFCs are more trouble than they are worth at present. The quality is too low, and the reliability is too low, and complexity is enormous compared to a simple tungsten globe which has (pretty much) only one component and two connections.

at 4/8/2009 8:03:37 PM, posthigh said:
Hoping to see a comprehension that line coupled caps are very low impedance at high frequency.

Translation:
Harmonics are absorbed by the same counter-measure that improves PF on the grid.

Point of load solutions are good for the economy though.

Here's a question:

Do real planets burn things for energy?

25 years of power design here.

at 4/8/2009 11:07:49 PM, cdc_eugene said:
With CFL bulbs, as most everything, you get what you pay for. I''ve seen very good lifetimes for nice full spectrum name brand bulbs and no-name bulbs bought from a good lighting store. costing $6 or so, I''ve consistently gotten lousy lifetimes from the $2 home center CFLs.

As for the mercury, in my area there are several stores that recycle CFLs and fluorescent tubes for free.

at 4/9/2009 3:58:38 AM, Tiamation said:
Whups! Good call after all, as reactance from house copper does not fix power factors (typ. < 0.52 for CFLs and test rigs in the lighting aisle trouble; Tube Testers 2.0?) Regenerative amplifiers, anyone? Protective mobiles which do the charge storage deed to spackle up sinewaves?

Then there are end of life power and waste management profiles....
nee: peswiki.com/index.php/Directory:Compact_Fluorescent_Lighting_(CFL)_Downsides

I had a CFL last 4.5 years in a small globe; until the heat-bleached note and penny spacer at the top were dislodged. Notes on aluminum foil next time?

at 4/9/2009 4:01:27 AM, rat said:
As with all quantum devices as the power factor increases
so to emissions
(electromagnetic). In particular [with this device]the 260 nm (mid to long shortwave)UV.
This frequency in particular
dimerises aminoacid Tyrosine.
Thus making it impossible for hair folicule cells to form Keratin required to build hair.
Almost any polycarbonate transparent / translucent will
block but even today people are still burning their hair off.

at 4/9/2009 9:44:35 AM, Rod said:
Don''t understand the problem. Large installations of flourescent lighting, i.e. malls and big box stores, the utility installs banks of PF correcting capacitors. Problem mostly solved. I realize their lights are basically on all the time so is a constant load, but it would be equally simple to add fixed capacitors at the transformer feeding houses with large CF or other such loads.

We metered in KwHr and KVar''s at the untility I worked for and was a penalty or rate adjustment for PF.

at 4/9/2009 10:56:50 AM, Marc said:
Kill-O-Watt ? if the reference is to the power meter made by P3, the correct name is Kill-A-Watt

at 4/10/2009 2:18:34 AM, Sophie said:
I have a question for PureSpectrum. Are you saying that your company will launch a dimmable, high-power-factor CFL that costs lower than no-frills CFL in the market now? Or you meant your CFL will be priced lower than other dimmable CFLs? (When I said no-frills, I meant low-power-factor CFLs without dimming function.)

at 4/11/2009 6:27:51 AM, Jack said:
A typical CFL rectifies the input 120V line, sort of filters it and then powers an inverter running at 40 or 50 KHz from the rectified line voltage.

If you look at the current consumed by the CFL, you will see that it is concentrated over a rather short portion of the AC cycle.

This is not a classic inductive load power factor issue that can be corrected by series capacitors, but rather a peak current problem, which causes harmonics and other bad things in the power distribution network.

I've provided some current and power waveform measured data at my web site. I can't post the link, but if you search for Clifton Laboratories CFL it should be at the top of the Google result.
Jack

at 4/11/2009 10:20:44 AM, John said:
Call me an old cynic but it occurs to me that a manufacturer could claim "near-infinite" efficiency by designing for near zero power factor. In the example this discussion started with he could claim twice the efficency of a unity PF light. Does this mean it''s real?..No! It is just that the power is not dissipated in the CF bulb but in the supply. As for distorted loads, it has always been a real frustration to me that these are described using the term Power Factor which is quite wrong.

at 4/11/2009 11:01:50 AM, Dennis M. in Nevada said:
People who live off grid are always looking for low wattage consumption devices and often employ CFl''s. So what will be the effect for the off-grid people who use sine wave Inverters such as those made by Outback Power and Trace?

at 4/13/2009 2:32:53 PM, DUP said:
PHILIPS HAS hpf cfl''S ALWAYS HAD THEM AVAILABLE, EXACTLY FOR LARGE INSTALLATIONS THAT HAVE HUNDREDS AND HUNDREDS OR MAYBE THOUSANDS. sO DOES ge AND oSRAM, WHAT''S THE BEEF? Philips invented the CFL hard to believe it''s been around over 20+ years, they gots smaller and cheaper, but they are already obsoleted by LED getting better and better, how could anyone still be using and incandescent lamp for general illumination in the 21st century, they are room heasters, not light Wake up, If you are still using 20 year old appliances at home, don''t worry about your few CFL lamps causing any issues, get some modern efficient appliances from GE of course. Amazing how non issues become an issue if someone wants it to be. Maybe GE, Philips, Osram have stirred the pot to get people warmed up for LED, like Freon became bad after the thing was used for 50 years, then new stuff with new patents was available, can''t function if ya don''t have new stuff to make and sell. New is ALWAYS better. T5 is also better than T8 mlamps, smaller more efficient etc.If you still use T12''s what planet are you from?

at 4/15/2009 8:58:45 PM, SteveP said:
I like the ability to choose a color temperature that fluorescent lamps provide but have many applications where they "don't fit".
Can anyone point to a CFL that does three simple things;
1 operate inverted in a closed can light,
2 Turns on instantly (> 95% brightness in 1 Sec.)
3 Dims to 25% or less of full brightness.

at 4/16/2009 11:29:08 AM, ZZMike said:
When you say "CFLs are still an efficient form of household lighting,...", do you mean "compared to oil lamps or candles"?

at 4/16/2009 11:31:19 AM, Skip Berne said:
Not sure what to say about all this. actually surprized to hear this (actually read it). with CFLs I have knocked my sailboat power usage from 900W to light the interior and running lights YES running lights first tried the 12 volt led approach. stuck one of those AWSOME 4w candelabra guys in the port lights and mast light, PERFECT. and you can see me 4 miles away!.

STATS: I use a measured actual 50 watts including my 8 watt pc. measured by current x voltage. and watt meters really is 50 watts.

APC 120 watt inverter ran for 6 days on my battery before giving up the ghost.

WHAT IS UP WITH THE PF?

at 4/16/2009 11:35:46 AM, JiM said:
1. "start up" current is not the issue.
2. yes they DO waste twice the distribution power compared to a PF=1.
3. most "modern efficient appliances" are heaters and the power draw has not changed. The new stuff DOES have a considerably shorter service life however.

This whole bag of reader comments reminds me, sadly, how few supposed engineers know what they are talking about and how willing they are to pontificate in public on issues they are not versed in. Ms. Connor got it right but everyone wants to be a critic to show how little they understand. Kids, these days

at 4/16/2009 1:06:10 PM, Noor said:
Someone stated that ''they are already obsoleted by LED getting better'', but I looked up LED efficiencies: 20-60 lumens/Watt compared to 40-70 for CFL and 30-110 for linear flourescent. Seems like they''re still a ways away.

at 4/16/2009 6:23:17 PM, Arv said:
How much mercury in a normal CFL bulb? What is the EPA recommendation for maximum mercury that will have negative affects on human body systems?
How are CFA's normally disposed of...throwing them in the trash. How much CFL based mercury ends up in landfills?

at 4/16/2009 8:33:32 PM, Tonehack said:
To JiM: Very well put!
OK people; many of us were not told the whole story about PF in school, PF is not simply the phase angle between voltage and current sinewaves. It aslo involves waveform distortion (harmonic content in the current mostly). The old simplifications do not hold up anymore! Capacitors on the power line do not make the problem go away. They are for power line inductance anyway.
Another poster brought up an interseting point about the net efficiency of a CFL with added PFC circuitry baing possibly as bad a power waster as the original CFL. I do not agree that this has to be the case.

at 4/16/2009 8:39:05 PM, Tonehack said:
I should have said that we were told the whole story in school, but we only remember the simplification with pure sine waves and not the rigorous math that came before the simplification. That is, unless we had to re-learn it on the job!

at 4/17/2009 4:44:02 AM, Stefan said:
Hm, the discussion went a little bit off the subject, did it? If you want to learn how to use PFC electronics go take a look at our web site, we have applications for LEDs as well as CFLs. We have no choice, incandescent lights will go away. Others have decided about that already.
www.powerfactorcorrection.de

at 4/17/2009 9:00:36 AM, kevan said:
I did my own experiment on this :

www.youtube.com/watch?v=LeCqreRMzKM

Without power factor correction you do need more energy to light these things up!

Kevan

at 4/17/2009 10:10:15 AM, SteveP said:
Kevan, Super video. Clearly shows CFLs need more power than stated on the box. Couldn't read the red text at the end after all of the compression.

at 4/17/2009 2:02:38 PM, SteveU said:
Kevan: You are demonstrating a real problem but your interpretation is flawed. The generator regulator is unstable because of the CFL negative resistance. It’s a feedback problem, not a loading problem. Also, the current meter is probably a peak detector, which will read a lot higher than the RMS value. To you folks who are not familiar with the operation of switch mode power electronics: Please update your knowledge before posting comments or you will just look silly as so many have done. Another point: the way to make a high PF, dimmable CFLs is remove the DC storage caps, not add a PF circuit. Also, I use a CLF in my trouble-lite because 120V incandescents are so delicate. Automotive incandescents are more robust because they are low voltage making their filaments shorter and thicker. I have had a number of cheap CFLs fail in the cold, used as yard lights. It is always a filament failure. As you may know, classic florescent lamps do not work in the cold (~< 0C) without special custom electronic ballasts. In general, measuring the performance of current products does not mean those product represent the limitations of the technology. Many LED lamps, for example waste most of their power in voltage dropping resistors because it’s cheap.

at 4/17/2009 4:30:35 PM, SUPPLIER said:
SDS-23 from U Lighting America is a dimmable >0.90 power factor 23 Watt. Have been using them for a year. Tested on Kill-a-Watt also. If it fails within 7 years, U Lighting will replace. If in California-no receipt needed. Available at Grocery Outlet, Save Mart & Rite-Aid FYI

at 4/20/2009 9:24:57 AM, M. Simon said:
Re: Stefan at 4/17/2009 4:44:02 AM - "we have no choice". A depressing comment on what the US Government has become. And my lights are ALL CFL. Have been for about 4 years.

at 4/21/2009 12:46:46 AM, ZiH PFC said:
Hi there. While reading the article and comments, I am happy to see that people care about energy wastage. Most of the people think, that CFL is the golden solution for the global energy problem. By the way, the company I am working for developed a PFC adder module for CFL lamps (E27 socket). If interested: www.pe-icdesign.de

at 4/23/2009 4:06:56 AM, Phil said:
A side topic perhaps, but I am one of many people who ''suffer'' under CFL and similar lamps. Not headaches as such, but they are not good for my well being. The governments of the World appear to be discriminating against people like me who have difficulty in living under CFL lamps. It matters not to me whether they consume more or less power than advertised ... they are horrid horrid lamps!! And I will be using them as little as possible. I am completely in favour of energy reduction, but CFL''s are not the answer!

at 4/28/2009 12:57:33 PM, TS said:
It''s good to see that a few - a very few - respondents here are thinking about the mercury content. Teir power use pales in comparison to the problems that will ensue from the mercury. Yes, the amounts are tiny... but mercury is highly toxic in microscopic amounts. Yes, there are recyclers - but what happens before the thing gets to the recycler? I''ll bet a high percentage are broken when tossed in the recycle bin, at home or at the recycler. Broken glass means mercury *vapor* in the house - you couldn''t clean it up if you wanted to. There will be mercury contamination virtually everywhere that CFL''s are used.
The mercury from CFL''s is poised to become one of the greatest preventable environmental health hazards ever. LED''s are a far better choice, for many reasons. Marginally or even dramatically improving CFL efficiency is a non-issue compared to their long-term potential for irreparable harm.

at 4/28/2009 9:46:18 PM, fm said:
The mercury released from burning coal to power your incandescent lights outweighs what you''ll release from breaking a CFL lamp. Hg from power plants travels around the globe and ends up in the fish on your dinner plate.

How often do you break light bulbs anyhow? Are you playing baseball in your house? Certainly Hg-free would be better

at 4/28/2009 9:50:12 PM, fm said:
(continuing after being cut off)
LEDs are improving and will give more options.

I am willing to sacrifice Phil''''s comfort to have a habitable planet in 50 years (sorry Phil!).

at 5/5/2009 8:22:20 PM, RJ said:
There is more mercury in one silver filling in your mouth than 100 CFL's, which are at least sealed. The mercury in your cheap fillings will cause more damage overall, and when you urinate what has come out of your body goes into the ocean and the fish. Power plants release less mercury than the crematoriums! Please don't breath on me, especially while having a cup of coffee!
An ME's response to the EE's delimmas.

at 5/14/2009 11:48:03 AM, GuyWhoReads said:
Before applying the "Rubbish" label, you should have googled "CFL Life Orientation" and you would have seen studies describing the relationship. Obviously, more expensive/higher quality CFLs will be less affected, but its still true.

at 5/26/2009 3:15:51 PM, wesmontage said:
Comparing real watts in to lumens out, CFLs are 3-4X more efficient. When PF is taken into account, CFLs still consume less apparent power VA than incandescents with the same light output. If you want high PF in a CFL, buy a dimmable one.

The amount of mercury in a CFL varies, but the lamps with the lowest amounts (like Philips) contain less Hg than the extra emissions from an average coal-fired power plant caused by running a comparably bright tungsten lamp.

Anybody who says that LEDs still have lower efficiency then CFLs should try reading electrical engineering magazines like, say, EDN. Cree just announced 130+ lumen/watt LEDs. Surely Seoul Semi, Osram and Avago can't be too far behind. An 85% efficient PFC power supply for these devices is already very doable at reasonable cost.

at 7/2/2009 9:35:16 AM, basreflex said:
The better solution to this is to wire the house DC, and use a good quality PFC to AC to DC.
there are hardly any ac users in the hosue left, all modern machines use electronic drives, switch mode supplies etc, only your alarm clock, and old dimmable lamps.. even an inverter Airconditioner can run on DC.

at 7/2/2009 9:53:54 AM, lfsaum said:
I still wonder about the ability of cfl lamps to start in cold weather in an outdoor lighting fixture, or in my garage ceiling. For my garage ceiling, I was able to get linear flourescent fixtures with bulbs from Lowes that would start down to 0 degrees F. We occassionally get down to -10 F. though. ???

at 7/2/2009 10:32:21 AM, DaveD said:
I have used CFL's outdoors for the last year. In Minnesota cold they started, but were dim for a couple of min. The coldest I tried this winter -10F and they worked fine. I don't buy the cheap ones, I stay with major brands.

at 7/2/2009 10:51:13 AM, Mike said:
Ms. Conner:
Unfortunately, while the low power factor is a concern for electric utilities, it pales in comparison to the larger issue: harmonics.

As you state, the lamp has its own DC power supply. It is a "switching" power supply, like many found in computers and other electronics. These power supplies "chop" the 60 Hz sinewave and create harmonic currents that distort the voltage and current waveforms produced by the electric utilities. This distortion produces a heating effect in the utility's conductors and transformers and is not related to the "real" load on the device. Already utilities are having to increase the size of their equipment in order to address the harmonic content of their load. These changes will bring about higher costs to the consumer in the form of rate increases. In additon, the CFL's are utilized, typically, when the utility loads are at a minimum. That increases the other impacts of harmonics on consumer appliances. For example, any device that uses the utilities 60 Hz timebase for timekeeping will run fast. Also, electrical wiring in a building can become overloaded due to the heating effects of harmonics. This "green" product will, eventually, cause significant consumer expense; not to mention the pollution aspect of the mercury content in the lamp.

at 7/2/2009 1:45:21 PM, J. Acosta said:
The most significant problem for the described PF issue is the existence of current harmonics generated by those CFLs(non-linear loads). The utilities will see a nightmare in the future if they don't start getting prepared for the increase of current harmonics on their lines. PF correction with capacitor banks won't work for the harmonics and other passive filter techniques won't be able to work for the scenarios that are comming which are expected to behave with frequent changes in non-linear loads let say during a day. The best alternative are Active Power Filters (APFs) which cancell harmonics and adapt in time based on load changes. These are more expensive but do the perfect job. Utilities should start thinking on that alternative.

at 7/2/2009 4:08:35 PM, Markus Unread said:
The thing that amazed me about CFL's is the inrush current at startup. With a crappy peak hold meter, I am seeing 250W+ from a 25W CFL. Some lighting systems have ECB's (Electronic Circuit Breakers) and they respond fast enough to cut out when using CFL's that would normally be well within their load limit.

at 7/2/2009 8:58:11 PM, Just another engineer said:
Distribution loss vs usage loss. CFL is typically 3x more efficient in producing light compread to tungsten. Let's say tungsten PF is 1, and CFL is 0.5, do the maths. You should see that CFL wins. Also, power is distributed in very high voltage(low current) until it gets somewhat near your housing area. The ratio of delivered power vs power lost in distribution is >> 1. You don't lose 1W to deliver 1W of power to household. Minimising end-point usage losses is the way to go. You all has been toy-ed by utility companies... and I don't work for any lighting companies.

at 7/3/2009 12:48:57 AM, FrankM said:
It´s obvious that you can´t add a PFC to a $2.- CFL, but if you transfer the PFC and driver electronics to the fixture that drives several CFLs or LEDs, the picture changes. Over here in Europe, utilities promote the use of intelligent metering devices even for household current. And btw: what is the the power factor of the 100+ million CFL fixtures in use worldwide. My employer 3000 employees pays lots of euros for "blind" current.
VERY interesting discusion.

Frank

at 7/3/2009 1:33:07 AM, Ted Murphy said:
I would rather use 10W with PF of 0.5 than 100W and a PF of 1.0.

at 7/5/2009 12:47:31 AM, Dr. Eng. Mohamed Helal said:
Dear Sir .

Let me congratulate you for your hot topic and please allow me to add few tips to what you has mention about CFL power factor issue .
CFL uses high frequency to operate > 20000 Hz , when power factor is < 80% the harmonics are > 100% , the correction of Power factor is quite impossible , we may have to riconsider the circuit consumption calcolation including the harmonic effect and the VA consumed ( power meter will show the Watt consumption while generation need to supply this CFL with needed VA in addition to contribution for losses due to the High level or harmonics ) .
I puplished this concept during world congress engineering meeting in Egypt on Dec 9th 2004 .
In my country Egypt we changed the CFL requirments to be of HIGH POWER FACTOR > 92 % also we limited harmonics to < 25% ..
This changes made a huge savings for EGYPT , let me say that each 10 Million CFL according to this performance will save the cost of a midium power generation that costs 500 Million US$ in addition to fuel costs etc..
I'm quite confident that High Power factor or let me call green lighting CFL that respect the environmental issues will replace present CFL of low power factor ..

at 7/19/2009 10:34:52 PM, Raid said:
What I have found most interesting about this discussion is that so many have forgotten the point. It doesn’t matter if lighting is a big or small percentage of the problem, all that matters is that “we” fix the problem. The use of bulk Active Power Filters will only mask the problem, and encourage poor design, the best solution is to correct the problem at the source.

In a recent major construction project I specified an energy efficient design. The major plant was easy; in fact the payback on the energy efficient new plant was only a few years e.g. 4 x 2.5MW chillers with unity PF, THDI <7% (max COP of 14). The same applies for the lighting; if we tell the manufactures to provide a unity PF and low THDI solution then they all come back and say, yes sir.

If we as consumers demand energy efficient products, manufacture will supply them and the cost increase is not prohibitive. I think that consumers must lead the regulators if they are too slow to react.

at 8/6/2009 11:05:59 AM, DM said:
The comment about distributing DC in the house doesn't apply to southern homes. Despite plenty of electronics, the majority of my annual electric energy consumption is air conditioning, followed by refrigeration and CFL/fluorescent lighting, all demanding AC power. If I had an electric oven and stove, that would make the balance even more to AC. The trend among electronics is more efficiency and lower standby power, so I don't see this changing anytime soon.

at 9/18/2009 8:41:18 AM, PARTEQ Innovations said:
We are the technology licensing agency for Queen's University.

We have developed and tested a CFL ballast that is dimmable, has very high power factor (nearly ideal), 80% efficiency, and is dimmable.

Best of all, it is cheaper than the standard transformer based ballast used in most non-dimmable bulbs.

We are working to license this to the industry. I think it is much better than PureSpectrum's product.

see www.parteqinnovations.com

at 9/28/2009 9:43:01 AM, Energy Mad said:
High power factor CFLs are available in the U.S. right now.

I work for a New Zealand company called Energy Mad, which has been making high power factor (HPF) CFLs for over 5 years. We sell them under the Ecospiral brand in North America through an online retailer:
www.altestore.com/store
Just search for 'Ecospiral'.

I have yet to see a higher quality CFL on the market - we're Energy Star rated to 15,000 hours, independently rated at 0.96 PF and have less than 1.4 mg of mercury per bulb, plus high lumen output/watt and excellent light quality.

You can learn more about us here: www.ecospiral.com

We're currently working on a dimmable product that works.

at 9/30/2009 5:08:28 AM, Lenniustr said:

Great stuff! Keep it up

at 10/1/2009 11:40:58 AM, dick_freebird said:
Power factor may be bad, but what about paying
3-10X up front and finding that your "efficient"
bulb lasts no longer than a dumb old incandescent?
Seriously. I started replacing with CFLs a couple
of years back and half of them have died (even the
ones whose boxes proclaimed 7- or 10-year life,
read the warranty fine print and they're throwaways).
Throwing away mercury, heavy metal phosphors, and a
bunch of high-input electronics & packaging gripes
me a lot more than argon, aluminum, frit and glass and a hair's worth of tungsten.

I pity the Europeans, whose oh-so-stylish leadership
has banned "simple and good enough" in favor of the
hype.

at 10/1/2009 2:15:02 PM, Fixit said:
So the capacitors installed by Utility companies to correct the PF induced by inductive loads produced by all those power transformers of yester-years have to be disconnected? Back then, when you turned a TV or radio off, it was really "OFF". Funny, no one is raising issues about "Standby Mode power consumption" in todays electronic devices.

at 10/1/2009 8:13:22 PM, DVanditmars said:
The whole thing with power factor for CFLs, (and previously for PCs, TVs, and other entertainment products) brings up the discussion about using DC power in the home to power these type of devices...

at 10/2/2009 3:38:33 PM, Amcfarl said:
CFL's won't work at full power on 120Vdc as AC is needed to voltage double and power the sinewave resonant inverter inside. BTW as an electronics power designer and consultant of 40 years standing I have a design for an add-on which will correct the PF and improve the efficiency of CFL's in a home or office lighting circuit with a small 99% efficient external box (not capacitors). I also have a radically different design of LED bulb which has .96 PF and 96% efficient electronics and which will give >90Lumens/W with no flicker and 80K hours of working life to 70% brightness. I work on my own so need a partner company or companies to work with in the US and elsewhere. Any takers out there?

at 10/5/2009 11:33:21 AM, Gurudatta Sardessai said:
I think DC is the way to go. I have already convinced some houses here to have a separate DC wiring for Lighting, more for utility lighting like corridors, stairways and the like. I have got my own site www.12-24v.com where I am trying to get the idea of DC Lighting for the home. I do not use switching in my LED lights and that avoids any radiation as well.

at 10/5/2009 2:02:00 PM, dick_freebird_does_so_over_100_deg_F said:
Not only that, but CFs which have long since bleached the notes on their fixtures, exhorting future users to keep the coin-and-FIMO(clay) air gap around bulbs, fail after people take the coins (and airflow) away! What a world; I thought the baseboards would cedar-oil themselves by now. On the other hand, most everything seems to be self-lighting [shakes Kindle], so why bother until you get your hands on real winners.

Gurdatta; happy DC railing.

at 10/14/2009 5:58:12 AM, scottd said:
One last note. If you add the capacitance to any electrical load, the capacitance needs to be wired directly so it automatically is removed from being present when the lamp or other load is turned off. If not the capacitors will be present on your entire power distribution system and reduce power factor and cause an increase in amperage. Shouldn't be done unless you can measure wattage and power factor.

at 10/14/2009 6:00:36 AM, scottD said:
Sorry about not including ALL of this post in the last.

I've been monitoring the energy use in my home for 10 years with a dedicated multi channel logger that measures temperatures, volts, amps, PF, kVA, KW. I've been aware of the lousy power factor for a number of years. I'm an energy engineer that's currently retired. I was saving this for part of my dissertation but will likely not finish it so I decided to put this info out on the web.

As proof that something could be done with existing CFL's, I soldered a 5uf capacitor in parallel to two Lights of America circline self ballasted table lamps in my home (each uses a 22w circular lamp FC8T9 that is replaceable). I was able to increase the power factor from 0.556 to 0.978 with of course with a corresponding reduction in amperage. I found this to work only on CFL's with magnetic (heavy w transformers inside) ballasts and adding the capacitor to electronic ballast CFL's actually reduced the power factor. These two modifications have been working with no problem for about a year. The capacitors I use are only about 1" square and 1/4" thick in 5uf size. I’m sure the manufacturers could do much better size wise. GE biax CFL’s with magnetic ballasts and changeable lamps also can have their PF improved by adding a capacitor based on my testing. I’m sure there are other types of CFL’s that this would work on but none of my electronic CFL’s benefited, so I have only a couple of 15W CFL’s that are electronic.

I did the same thing to a fixed light fixture having two lamps, a 22w and a 32w and an advance magnetic ballast. This was the only occasion where the actual wattage was reduced. I added a 12.5uf capacitor permanently in parallel inside the fixture. Before the retrofit the fixture drew 60 watts at a pf of .58 .After the capacitor was added, the wattage reduced to 53w at a PF of .963 . The amperage changed from 0.855 to 0.464. I installed a toggle switch where I could quickly go back and forth from having the capacitors connected or not for verification purposes.

I did the same type correction on my refrigerator, dishwasher, and washer for a large reduction in current, big improvement in PF, but not wattage.

One last note: If you add the capacitance to any electrical load, the capacitance needs to be wired directly so it automatically is removed from being present when the lamp or other load is turned off. If not the capacitors will be present on your entire power distribution system and reduce power factor and cause an increase in amperage. I verified this by having the proper size of capacitors needed for the dishwasher (70uf) and seeing the effect on the PF and amperage of the entire house. Shouldn't be done unless you can measure wattage and power factor.

Manufacturers should definitely go to high power factor ballasts for obvious reasons. Right now I'm looking for a 15w CFL with high power factor, preferably made anywhere but in China. Does anyone have a suggestion? I need something compact so I won't be adding a capacitor.

at 10/22/2009 2:39:00 PM, Mukund Parelkar. said:
IAM LIVING IN MUMBAI
I come to know that many of the MALLs in Mumbai, India are suffering from this low pf of .57. since the current is nearly doubled, heating of wires and possiblity of short circuits and fire have increased. few of the malls have put special PF correcting equipment - a capcitor bank.

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