Comments on: Tech’s little green secret

By: Joseph

Joseph — Thu, 21 May 2009 17:15:13 +0000

We shouldn’t be so quick in discounting the idea of power factor correction. This is a common practice in the power industry. The idea of correct power factor on a household level, although may not be significant on a stand along case, it will be very significant if millions of households can improve their power factor by just a few percent.

When it comes to energy conservation, public education is the most effective solution. The majority of us can probably reduce our energy consumption eaily by 3-5% through simple things like taking the public transit; turning off unnecessary lightings; lowering the heat in the winter; using fans instead of air conditioners in the summer; buying energy efficiency cars, etc. Imagine if we all put in our effort. 3% for each household is insignificant, but 3% for the whole country is a completely different stroy.

By: Rick

Rick — Thu, 21 May 2009 17:06:19 +0000

PFC does work & does save users 10-15% electrical expense because when PFC is done correctly, it lowers amps, and helps recover line losses. The reactive load is made to look like a resistive load at unity.
Ohms law: Volts x Amps x PF x sqrt of phase = Watts
Line loss: Amps x amps x resistance = Watts
So if I optimize a system for power factor it will lower amps & line loss by reducing reactive amps in the circuit.
Example: 208 Volts with 100 Amp Loading 3 phase & .8 PF
208x100x.8×1.7= 28,288 Watts ( 28.3 kW)
After PF optimization: PF @ .99, amps lowered 30% to 70.
208x70x.99×1.7=24,500watts, ( 24.5 kW) a 13% drop in Watts
Then Line loss recovery:
Before: 10000 x r=Watts After 4900 x r= Watts-this usually gets another 7% in lowered expense.
Optimizing PF works to lower electrical costs.
All the meters I have ever looked at read volt & amp flux to generate the watts they bill. lower the amps, you lower the watts

By: david

david — Thu, 21 May 2009 14:34:55 +0000

It is debatable whether the energy savings are real. A power factor correcting device adds perhaps 6% inefficiency.

Residential customers won’t see any utillity bill decreases, and commerical only perhaps 1-3%, part of reason for this is it doesn’t make as much difference as some claim. (If it did, comercial customers would be given more incentive)

see for example: http://energystar.custhelp.com/cgi-bin/e nergystar.cfg/php/enduser/std_adp.php?p_ faqid=4941&p_created=1204908170

By: Cortland Richmond

Cortland Richmond — Thu, 21 May 2009 02:38:01 +0000

PFC isn’t everything; an incandescent bulb has a unity power factor, and really horrible efficiency, unless you need heat. And let us remember, even full-wave rectifier “wall-warts” are rapidly becoming a thing of the past, replaced (because of energy efficiency laws) by switching power supplies of MUCH better performance.

I suspect switchers won’t need PFC to provide most of the improvement we are talking about, and the reason for using it will have to be found elsewhere. EMI?

By: Youri Carma

Youri Carma — Thu, 21 May 2009 01:59:11 +0000

The problem with little secrets is that they are as unknown as big secrets so that maybe the problem that it shouldn’t be a secret?

Should it of the roof and I will spread the good news too.

By: Ron Wagner

Ron Wagner — Wed, 20 May 2009 23:43:17 +0000

In air conditioning periods your savings would be double. You won’t have to pay to get rid of the heat in your home. A good start would be to require this system for Energy Star approval, and expand the approval to small electronics.

By: cgil

cgil — Wed, 20 May 2009 15:12:43 +0000

It seems to me that PFC is mandatory in all Europe (EU) since 2001
normalisation rule is : EN61000-3-2
And yes it will be a good idea if US begins to care a bit more about the planet Earth

By: sam

sam — Wed, 20 May 2009 00:42:47 +0000

think about this as more consumer demand goes down they will said they are not making enough money so they increase rates. they would be fight anything that going to help

By: G. Karam

G. Karam — Wed, 20 May 2009 00:04:37 +0000

Irrespective of whether the savings are as large as the author claims or whether he stands to gain from the adoption of PFC’s what ultimately matters is whether the technology contributes to net energy savings. If it does then we ought to go for it.
If Europe has legislated the use of PFC then we canevaluate their experience in order to guide us.

By: Mike

Mike — Tue, 19 May 2009 23:23:43 +0000

I think the reason this has been avoided is twofold:
1. as mentioned, ignorance. I don’t think many people know about this; it certainly doesn’t get much media attention
2. it’s not flashy or expensive. It’s not going to grab headlines. The practical solution is not always the pragmatic one. For a president that thrives on big-ticket items, this is certainly not on the top of his priority list.

At the end of the article, you suggest that two things could increase the prevalence of this technology – consumer demand and government mandate. I think you’re forgetting a fairly powerful motivator: tax incentives. You can encourage companies to move to the new technology if doing so will save them money. If, as you claim, the businesses become entrenched in their established production processes, the tax incentives would not have to exist for very long to be permanently effective.

The benefit of tax incentives over consumer demand is simple: it would take a large amount of time and resources to educate and excite the public on something that is both arcane (most people won’t understand or care about the physics behind it) and mundane (a different plug? who cares?) to them.

The benefit of tax incentives over government mandate is that it allows the businesses to determine their own timelines for moving to the new technology. It gives them time to do research and development, and to modify their production processes accordingly.