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If PFC is important why don't we see the PFC products at bestbuys???


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#1 Schummi21

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Posted 13 September 2004 - 07:26 PM

hi, i am doing some research about PFC and trying to understand the dynamics in the marketplace. May be this will sound dumb but if PFC is so critical and important why don't we see pfc products at bestbuy beside surge protectors? also, wouldn't PFC drive down the revenue for the power suppliers? let's say i have a magical device, you attach it to your meter and it improves your PFC to 95% would anybody even consider buying it? i have seen some big capacitor banks with auto-switches..if these guys are able to manufacture those, what's keeping them from manufacturing a smaller one for use at residences? is there something they can't do? or is the market not there at all? thanks for your comments in advance...cheers

#2 leeeetao

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Posted 14 September 2004 - 02:20 AM

actually, there is market for this.
in some occassions(such as middle-frequence electric oven, welding machines,motors are widely used), reactive power compensated by capacitor bank will not
work because of harmonic. thus the power factor remains low.
We have set up more than 400 sets of harmonic filtering device all over
our country and electric penalty charges are deliminated while the power factor reach 0.95 in average.

#3 marke

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Posted 14 September 2004 - 07:16 AM

Hello Schummi21

Welcome to the forum.
You raise some interesting questions.

1) From a power suppliers perspective, yes there is definitely an advantage if the power factor is close to unity. This minimizes the line and distribution losses, and maximizes the loading on generators and transformers.

2) From the consumers perspective, there is only an advantage if there is some form of incentive. In some territories, there is a lot of incentive to correct the power factor, but in other areas, there is no incentive at all.

A poor power factor does not affect the KW drawn by the consumer unless there is a very long line between the meter and the load, so improving the power factor will not affect the KWHrs or units used. If the consumer pays for KWHrs only, there is no incentive and no market for power factor correction.
If the consumer pays for KWHr plus there is a surcharge for a poor power factor, then there is incentive, or if the consumer pays for KWHr and KVA maximum demand, there is also an incentive. Improving the power factor will reduce the current draw and therefore the KVA.

Domestic consumers pay for KWHr only, so there is no incentive to add power factor correction. Additionally, the power factor of a domestic installation is generally pretty good. Poor power factor is often associated with lots of induction motor loading as occurs in some industries.

Here in New Zealand, power factor correction is very commonly used in industry, but never in domestic installations.

Power factor correction can however, create other problems. The capacitors form a resonant circuit with the inductance of the supply and can be the cause of much electrical damage due to surges and resonances.

Best regards,

#4 Schummi21

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Posted 14 September 2004 - 03:06 PM

Hi. For some reason my previous post didn't go through so I'm typing again.

First, thank you very much for your comments. I really appreciate it.

i went ahead and did some more research online to better understand the market situation in the US. Looks like some of the power companies charge extra for poor PFC for customers with power consumption 100Kws or higher. I don't know if a regular home would consumer 100Kws per month but it is something to think about.

so the power suppliers would like to improve PFC whereever it makes sense, right? how do they do this? for the industrial use, it is obvious. through consulting and equipment but for the residential market??? i don't know yet.

i have couple of friends working for one of the power suppliers in my region so i will ask them or their colleagues about this. Of course will post my findings.

here is another thing I've found on the web. A product called energywise 1000 (http://www.josephpre...e/flat-line.htm). Now this product promises improving PFC and saving you money. i couldn't find how much it costs or how much it saves since the information on the web is poor and to be honest the deal looks kind of shady.

i found out that power suppliers actually sell capacitors and switches to help their customers improve their PFC. now i don't know how many of those capacitors they sell are bought by residential customers but i bet most of the buyers are industrial. also i've learned that some big machines actually have their PFC device built in!

it's all in the numbers...
how many households consume more than 100Kws per month?
what does the power suppliers charge you for poor PFC?
how much would it cost you to improve your PFC?
and how much would you save over time by installing a PFC device or a capacitor?

the numbers are certainly significant for the industry but i don't know how they lay out for the residential market.

how big of a consumption is 100kws? i mean do i consume a 100kws and pay $50 a month??? how much do i pay to the power company for poor pfc?

i hope to answer all these questions..but some of them i know i can't.

if the residential market is somewhat significant because of its size..how come the PFC equipment manufacturers for industrial use don't enter this market??? they know something we don't know???

Thanks again for your comments and pls continue to tickle and pick my brain and keep them coming.

Have a good one.
Cheers,

#5 marke

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Posted 14 September 2004 - 07:33 PM

Hello Schummi21

You apear to be mainly concerned with the power factor of the domestic installation.
The first question must be " does the domestic installation attract a power factor penalty?" and the second question is "what is the average power factor of the domestic installation?"
Answer these two questions, and I think all else will be answered.

There are sales organisations out there selling products that "reduce the power bill" of the domestic installation, but the proof and explanations are generally lacking. The bottom line is that you can only save what is being wasted. A poor power factor causes energy losses in the distribution system, but not the load. It will not reduce the KWHr consumed.

There are energy saving devices on the market that are based on the Nola invention of the late 70s. These devices reduce the voltage applied to induction motors when they are operating at light load and low efficiency and reduce the iron loss in the motor. These devices will also improve the displacement power factor but reduce the distortion power factor. For mor information, look at http://www.lmphotonics.com/energy.htm
Best regards,

#6 jraef

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Posted 26 September 2004 - 09:04 AM

Schummi21,
Speaking from the US, I can address the other questions that you had.

I don't know where you got your figure of 100kW as a cosumption threshold. I read an article recently saying that the average residential consumer useage has risen from just over 8100 kWH/year in 1988 to over 9450kWH/year projected for 2004. Even if you meant 100kWH / month, it is still very low. Regardless of the threshold number, there are probably less that 1% of all residential users here who would even have recognizable poor PF, and that would be because they are very wealthy and have lots of toys. They, of course, would be unlikely to care one way or the other how much power they consume and would be unlikely candidates for savings devices.

That said, I know of no utilities that charge ANY residential consumers for poor PF, and I deal with customers all over the country. I live in California, a state notorious for power supply problems. The largest utility, Pacific Gas and Electric serving San Francisco and much of the rest of Nothern California, does not even charge PF penalties to industrial customers!

The fact is, the vendors of those devices tend to twist the presentation of the facts to allow you to beleive this is a bigger issue than it is. Their primary customer base is uninformed consumers who are desperate to find some "magic box" that will relieve the shock and pain they have from watching their energy bills skyrocket. They believe it because they want to believe it.
"He's not dead, he's just pinin' for the fjords!"




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