Do energy capacitors save energy in the home?


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Old 06-20-09, 06:27 PM
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Do energy capacitors save energy in the home?

I have been given a capacitor by my company to install and then document any energy savings over a 6 month period in my home. I've been told that it can save me anywhere from 10 - 25% on my electrical bill and that it's easier on my appliances. Apparently it affects anything with an inductive load. The company had a power factor reading done recently and I was told it was 5 with 1 being the best you can get. From what I' ve been told it seems to make sense and I'm not out any money, but before I sell anything (this is NOT a sales pitch as I'm not mentioning any company or product name nor will I) I want to know if it is legit or snake oil. I've done some reading online and it seems there is no in between on this product. You either believe in it or you hate them. It makes sense to me on how and why it would work, but that doesn't mean it actually does. What do you electrical guru's have to say? Thank you in advance.
 
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Old 06-20-09, 06:36 PM
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Hissss..Hissss....
What company..your power company?

Some people will say they saved a ton..just like the hydrogen generators for cars. I belive its all because they were more aware of their usage.

No Pro..just a dis-believer.
 
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Old 06-20-09, 06:39 PM
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It'll cost you more in the long run. Power factor correction works better if you had constant motor loads in your house. Like an industrial facility having motors constantly starting all day.

The one I had pulled a constant 7 amps times 24/7 equates to a lot of unnecessary energy consumption.
 
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Old 06-20-09, 06:50 PM
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Originally Posted by Gunguy45
Hissss..Hissss....
What company..your power company?

Some people will say they saved a ton..just like the hydrogen generators for cars. I belive its all because they were more aware of their usage.

No Pro..just a dis-believer.
No not my power company the company I work for. It's a new product they want to market and I'm a guinea pig. I'm trying to educate myself on this concept.
 
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Old 06-20-09, 06:56 PM
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Originally Posted by wirenut1110
It'll cost you more in the long run. Power factor correction works better if you had constant motor loads in your house. Like an industrial facility having motors constantly starting all day.

The one I had pulled a constant 7 amps times 24/7 equates to a lot of unnecessary energy consumption.
It's funny you mention that because that was one of the suggestions I had already. It doesn't come on when needed, it's on 24/7. It draws 250 watts of power according to the manual.

I have a 20 year old house and they claim that it works better the older the home, and that's it's not very effective on a new home with a newer furnace and appliances, etc. Since I heat with wood, I would most likely turn it off in the winter as I never use my furnace but my AC is running a lot here in the south. In case you didn't know it gets HOT here. Our AC and ceiling fans are going a fair amount of the time this time of year. Also my wife works from home and is on 2 computers alot. All of those are inductive loads correct?

That all being said, is the concept of it sound or is this fancy electrical talk wrapped up in an energy saving package?

Thank you for your reply!
 
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Old 06-20-09, 07:00 PM
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Power correction is most definitely a money saver but only for large commercial users.

There is a great deal of technical info out there on this subject and you testing it in your home will not really prove anything.
The savings are for inductive loads which in a home are any motors.
Any resistive loads like stoves, heaters, water heaters and lighting are not affected by power factor.
 
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Old 06-20-09, 07:03 PM
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I was going to try to explain it but your better off just reading here: Power factor - Wikipedia, the free encyclopedia Everything you want to know about power factor but were afraid to ask.
Also just Google "power factor"

My understanding is homeowners do not have enough inductive loads to make it worth while.
 
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Old 06-20-09, 08:05 PM
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Originally Posted by tlhfirelion
It's funny you mention that because that was one of the suggestions I had already. It doesn't come on when needed, it's on 24/7. It draws 250 watts of power according to the manual.

I have a 20 year old house and they claim that it works better the older the home, and that's it's not very effective on a new home with a newer furnace and appliances, etc. Since I heat with wood, I would most likely turn it off in the winter as I never use my furnace but my AC is running a lot here in the south. In case you didn't know it gets HOT here. Our AC and ceiling fans are going a fair amount of the time this time of year. Also my wife works from home and is on 2 computers alot. All of those are inductive loads correct?

That all being said, is the concept of it sound or is this fancy electrical talk wrapped up in an energy saving package?

Thank you for your reply!

it DRAWS 250 watts of power? Then how is it supposed to save you money?

In a typical scam, I mean power saving device, a capacitor is used to correct power factor. The problem is, residential power costs are not affected by poor power factor so correcting the PF will not save you a penny.
 
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Old 06-20-09, 11:58 PM
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I am pretty much in the boat with other guys mention about power factor correctioning that normally used on very large commercal/ industrail user they can get the benfit of it but for resdentail useage IMO it kinda not really justify the cost for the saving.


the common power factor correcting devices on large commercal / Industrail customers are :

• Capitor banks

• Schyronous motor { common used with air compressor or other consat speed / load useage }

Merci,Marc
 
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Old 06-21-09, 05:53 AM
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Power factor is measured on a scale from 0 to 1, sometimes also expressed as a %. PF 0.5 also = 50% PF.

If the power factor at a premisis is too low, the utility company will charge more for the electricity. They REQUIRE a company that has very large motors, etc. to correct their power factor closer to 1. If they catch you trying to lower the power factor at your house, they will cut you off, or raise your rates.

Power Factor Correction means adjusting to get closer to 1.0 ( most users will be in the 0.9 to 0.95 area). Artificially LOWERING your PF is probably not legal.
 
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Old 06-21-09, 06:34 AM
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And as already alluded to, the main reason capacitor banks save money for commercial customers is that the utility has installed a PF meter. If the customer's loads make the PF meter go out of bounds, there is a substantial, sometimes massive, penalty automatically added to the bill.
 
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Old 06-21-09, 06:56 AM
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We have previously discussed a similar device here:

http://forum.doityourself.com/electr...er-device.html
http://forum.doityourself.com/electr...wer-saver.html
http://forum.doityourself.com/electr...wer-saver.html

In my opinion there is no way power factor correction can save anywhere near 25% on a residential service.

Even still, the method your employer has suggested is a completely bogus test as you have no control to compare the experimental data to. Simply observing whether you think you saved power or not is a placebo effect.

If he was truly interested in testing this device, he would get two sets of identical residential appliances, run them through residential meters, and install the unknown device on one of the services and leave the other as is. Operate the appliances on identical schedules over a period of time and compare the readings on the meters at the end of the test. This is the only way you can make any sort of claim of savings specifically caused by this device. Anything less, is a scam in my opinion -- in fact, the inventors of this device should be eager to provide you with this type of specific scientific data which you could then repeat the experiment. They did test it, right?
 
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Old 06-21-09, 07:36 AM
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You will not save any money. You are billed for kilowatt hour usage and that usage will not change with your power factor other than the possibility of minuscule line losses. Even that is debatable since the capacitor itself is drawing current, so it's pretty much a draw on line losses in my mind.
Power factor is a ratio of your actual power consumption (watts) divided by your apparent power (Volts times amps or VA) . The reactive component provided by a motor or a capacitor will vary the total VA, but it will not change the watt component. Since residences are billed on watt usage, your bill will not change.
PF can be leading (i.e., primarily capacitive in nature) or lagging (inductive). So when your inductive devices are off (fans, compressors, etc.) your power factor will swing the opposite way due to the capacitor. A 95% PF leading is just as bad as a 95% PF lagging.

That's from the homeowner point of view.

From the utility point of view, they're great (if they're in use at the right time). Bad PF results in lots of line loss for utilities and inefficiency in the generators, all of which you ultimately pay for in losses, line improvements, new generation, etc. Recent legislation has demanded that utilities raise their standards for PF (in Texas it is now 97%) so anything a consumer did to help would ultimately help everyone. The most practical way for this to be accomplished (IMHO) would be to require air conditioner manufacturers (or refridgerator manufacturers) to size running capacitors in their units to approach 100% PF while running, but only while running. For all I know, that may be a new standard....I'm not in the AC business. Anybody out there know?
 
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Old 06-21-09, 10:42 AM
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Originally Posted by WFOWFO
[.

The most practical way for this to be accomplished (IMHO) would be to require air conditioner manufacturers (or refridgerator manufacturers) to size running capacitors in their units to approach 100% PF while running, but only while running. For all I know, that may be a new standard....I'm not in the AC business. Anybody out there know?

WFOWFO.,

The engery pact did allready rasie the standard for the motor effecently up much higher they have to be at least 97% PF or higher and most med to larger new motor allready running 98 to 99% PF the only way to hit a full 100 % is get schyrounous motor or written pole motor one of the two anything else the bet is off.

But really it was in effect about 5 maybe 8 years ago and the motor manufacters slowly catch up with it.

Merci,Marc
 
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Old 06-22-09, 08:18 AM
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Originally Posted by WFOWFO
to size running capacitors in their units to approach 100% PF while running, but only while running. For all I know, that may be a new standard....I'm not in the AC business. Anybody out there know?
I believe this is one of the criteria for the energy star program. Not unity power factor but something like 0.98 during normal operating conditions. So many appliances out there already have corrected power factor up to the limit which is practical.
 
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Old 06-22-09, 10:57 AM
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Originally Posted by ibpooks
I believe this is one of the criteria for the energy star program. Not unity power factor but something like 0.98 during normal operating conditions. So many appliances out there already have corrected power factor up to the limit which is practical.

With my70's GE refrigerator plugged into a kill-a-watt the power factor is 1.00. When the compressor is running the PF drops to 0.62

I'd guess this isn't a very efficient motor?


Baldwin
 
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Old 06-22-09, 11:12 AM
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Tlhfirelion, If you give your company a copy of the replies to this thread could you let us know their comments on the replies and if they decide to carry the product. Thanks.
 
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Old 06-22-09, 12:09 PM
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Originally Posted by Baldwin
the PF drops to 0.62

I'd guess this isn't a very efficient motor?
There are other parts of efficiency beside the power factor, but it is correct that the low PF is an indication of an inefficient motor. Chances are the old fridge also has an inefficient compressor design and poor insulation and seals which further contribute to the overall inefficiency.

What that power factor essentially means is that only 62% of the energy which is consumed actually goes toward making rotational movement in the motor shaft. The other 38% is wasted in supporting the magnetic fields within the motor.

Along with the theme of this thread, you don't pay for all of that wasted 38% based on the way that power companies meter residential services. It doesn't directly correlate to cost except as an amortized expense that the power company simply rolls into the base residential rate.

If you have a commercial meter, you pay for all of the wasted power plus a possible surcharge for poor power factor. I once had a customer who ran a small warehouse and had purchased some used cargo lifts and installed them himself. Turns out the power factor on the old lifts was about 0.60 and the power company sacked him with a $2,000 surchage during the first month of operation. He called to get some capacitors installed ASAP to correct the PF problem.

On the original topic, a cheap modern fridge will typically pay itself back in about 12 months of energy savings.
 
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Old 06-22-09, 12:24 PM
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Originally Posted by tlhfirelion
It doesn't come on when needed, it's on 24/7. It draws 250 watts of power according to the manual.
Doing a quick calculation of 250 watts continually for a month comes to 180 KW used by the capacitor. At an average electric rate of 10 cents/KWH, this device would ADD about $18.00/month to your electric bill. I highly doubt if the energy it saves will offset that.
 
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Old 06-22-09, 07:10 PM
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Originally Posted by Baldwin
With my70's GE refrigerator plugged into a kill-a-watt the power factor is 1.00. When the compressor is running the PF drops to 0.62

I'd guess this isn't a very efficient motor?


Baldwin
I didn't know the kill-a-watt also showed the PF. I might look into one of them!
 
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Old 06-23-09, 12:31 AM
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Tolyn Ironhand.,

Yeah they do have PF feature in there and I throw in the link so you can able look it up.



P3 - Kill A Watt

Merci,Marc
 
 

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