PFC for residential users 6

[Breaker]

I have come across a device which claims to save on your electricity bill. It is a UK device. I believe it is a con and want to take action against them, but before i do this i want to be sure that i haven't got it all wrong.

The device is a small unit which plugs into any socket in the home, and it claims to perform Power Factor Correction (PFC). However UK residents are charged on kWh and not kVA like industrial users, therfore PFC would not save on the electricity bill.

Also the claim that it can be plugged into any socket is strange, as i can't understand how it could monitor the current, such that it could determine the existing power factor angle, and therefore decide on how much capacitance to switch in. Therefore, whether it does perform effectively PFC is suspect.

Please give me you opinion on this, as i am sure they have already made millions on the unknowledgeable consumers.

 

[DougMSOE]

You are correct.
It is a con.

 

[Baldor]

It might be a similar device to the one describedhere:

http://yarchive.net/electr/green_plug.html

 

[ScottyUK]

Baldor,

What a cracking link!

Breaker,

I agree with the above - I can't imagine how it could possibly work, and even if it did, to what end? It is probably targeted at domestic users because it would be shown up as a fraud quite quickly by the industrial users who would see that it caused no improvement in their reactive power usage when they received their bill. Domestic bills don't show kVA, so the manufacturer can claim whatever he wants, as few will have the means to prove otherwise.

Can you get hold of one and test it? Send the results to the BBC's Watchdog programme and see if they'll feature it. Might make you a TV star too - more money and less aggravation than being an engineer!

 

[jraef]

This is the same thing as "energy savers" touted in industrial circles as well. There are lots of threads devoted to this in the Electric Motors and Controls forum, most of which will show up under a keyword search of "energy saver". Here is one of the latest.

thread237-74129

The upshot is that although they work in theory, they are highly impractical. The only electric motor in a common household that could possibly be effective would be the refrigerator, but being a sealed intetgrally lubricated motor there are inherant dangers associated with using them there. The link above is a good testament as to the likely result (although I disagree with some specifics of his conclusions).

Just to help you understand the terminology, by saying they are PF controllers does not mean they controll PF, they measure PF and USE it as the determining criteria for deciding that it is OK to reduce voltage to the motor. This saves a small, and I mean very small, amount of energy losses IF the motor is unloaded. The problem is, not only are the savings a small percentage of a small percentage, but when do motors run unloaded for long periods of time?

Quando Omni Flunkus Moritati

 

[Breaker]

ScottyUK

I thought i would send details of the company and the product to the Trading Standards Agency. The company claims they have sold millions worldwide, and they have a fairly decent website which looks professional, and they have been putting leaflets in our local paper. So I wouldn't be surprised if they have put similar advertising material in other local newspapers around the UK.

I don't think i can mention the name of the company here, unless the site administrator will let me. Otherwise you could all see what a scam it is.

The unit costs £49.99 so i don't really want to spend that on testing. They also claim that there is a money back guarantee if it doesn't save you up to 25% of your electricity bill. But i have looked at their terms and conditions, and it is a real hassle, with you needing to produce previous bills, and the money back period is only 3 months, which is hardly enough time for a thorough test.

 

[ScottyUK]

Hi jraef,

The units you're talking about serve individual loads and 'improve' their characteristics, but the item Breaker is referring to seems to claim to do this for the whole house, without any CT or similar to sense load current. My initial reaction was that it might be using principles similar to the active harmonic filters which draw reactive current in antiphase to the load, but this doesn't work without any current measurement, and wouldn't be available for £50.

Breaker,

Can you post the weblink? I think Dave (Staff) would let us make our own judgement. This has happened with a number of these 'power savers' in the past, although they seem mainly confined to the US up until now.

 

[Breaker]

http://www.ep-systems.co.uk

 

[jbartos]

Suggestion: The questionable power saver should be analyzed what is its principle of operation, circuitry, and application intent. It is often seen that advertised products do not deliver what promised or some additional measures must be taken for the product to deliver what is advertised.

 

[stevenal]

"You will reduce your electricity bill by up to 25%"

Anywhere from negative infinity to 25%. No lies there.

"Fully compliant with all major safety standards...The device can store energy for up to 10 seconds after it is switched off, therefore wait for at least 10 seconds between switching off the mains and un-plugging the device."

Guess those standards need some work.

 

[ScottyUK]

Is this thing a box of capacitors, relying on most loads being inductive?

The whole thing sounds like bull5h1t as far as I can see. How on earth does it measure the current in the whole installation in order to correct the PF?

 

[Breaker]

Also amusing!!

On the advertising leaflet they distributed, the following words were printed "Fully Complaint with Safety Standards"

 

[Breaker]

I have wrote to the company with similar queries as above. Below is the reply i got back. I think they are still talking rubbish!!

Thanks for your email and your questions. Here are the answers to your questions.

1. Reducing KvAr means that your devices will work more efficiently and that they will not waste energy in the form of heat and other losses etc. KVAr has an impact on the total KWH which can be worked out from the vector diagram. Also please note that just because most of the electricity meters say KWh on the front, it doesn't actually mean that you are charged for KWh only.

2. Our device uses filters and capacitor banks. As all the rings and nodes in the house share a common neutral line from the distribution point onwards, our product with its unique patented technology automatically senses and reduces the reactive power consumed by various appliances. Please note that the power factor should ideally be close to unity.

To show our confidence in this technology and to offer our customers full peace of mind, we offer a unique 'buy with confidence' 3 month money back guarantee. You can purchase the unit and use it for 3 months. If after 3 months, you feel that our product has not saved you money on your electricity bills, you can return the product to us and we will refund you your money.

 

[jghrist]

If capacitors are placed on a branch that has no inductive load, the losses will be increased because the current on that branch will increase I[sub]total[/sub]²=I[sub]resistive[/sub]²+I[sub]capacitor[/sub]². The only loss reduction would be in the wire between the service panel and the meter, a large, short wire with little losses to reduce. Even if placed ideally on the outlet where an inductive load like a refrigerator is plugged in, the loss reduction will only occur when the refrigerator compressor is cycled on; there will be a loss increase when the compressor is cycled off.

The bit about "please note that just because most of the electricity meters say KWh on the front, it doesn't actually mean that you are charged for KWh only." is total bull sh**.

 

[stevenal]

It gets better. From the legal section:
"all warranties, conditions or other terms whether express or implied by statute or common law or otherwise are excluded to the fullest extent permitted by law.In particular We make no representation or warranty that the Goods are either of satisfactory or merchantable quality or fit for any purpose or that they conform to any description."

 

[jraef]

"In particular We make no representation or warranty that the Goods are either of satisfactory or merchantable quality or fit for any purpose or that they conform to any description."

WOW! That is the biggest disclaimer I have ever seen! Basically, it is saying "Everything we say can be total hooey and becasue we told you that now, we are not responsible for you believing it."

What planet are these guys on?

Quando Omni Flunkus Moritati

 

[busbar]

Poor Frank. (Nola)

 

[jbartos]

Suggestion: Visit

http://www.thomasregister.com

and type Energy Saver under Product or Service, which will return categories of energy savings with associated number of companies offering their products.

 

[jraef]

busbar,
I agree, he must be spinning in his grave. It just goes to show you that even with the best of intentions, there is always a way for someone to make your contribution into a detriment to society.

This subject has prompted me to change my sig line.

"Venditori de oleum-vipera non vigere excordis populi"

 

[ScottyUK]

jraef,

It's a long time since I did Latin.

Snake-oil salesmen do not << ??? >> the people?