Another woo "free energy" device?

[MattusMaximus]

Okay, I just got an email on a physics list I frequent about this website...

FreeEasyGreen.com

These folks sell a device they claim will do the following:

Here's How We Help You Reduce Your Electric Usage and Save Money on Your Electric Bill

1. Your home is filled with motors (such as your air conditioner, refrigerator, washer, dryer dishwasher, furnace blower motor, etc.)

2. The Power Save unit reduces the amount of electricity drawn from the utility company by storing some of the electricity in it's capacitors.

3. The technology applied by the Power-Save unit supplies that stored electricity back to the motors when you need it, thus causing you to decrease the demand from the utility.

When you decrease your demand from your utility, your meter slows down and you use less electricity. You've already paid for that electricity. Why waste it when you can store it and reuse it again!

I responded to the list with the following:

At first glance this looks like big-time woo-woo to me. If all you're doing is storing the energy for later use, you still have to pay for it in order to charge up the capacitors in the first place. In fact, I would venture to guess that over the long term this device actually costs more in electricity because no storage device will be able to return 100% of the stored energy back to you. So it's a double-whammy: you first get screwed buying the bogus device, and then you get hosed again with slightly higher electric bills from the less-than-ideal efficiency of the energy storage.

Can anyone see anything wrong with my comments? It seems that I'm the only one (so far) on the list to make these points, and I hope I'm not screwing anything up.

 

[Seanette]

Bob's the electrical expert in our family, but you make sense to me.

 

[Dave Rogers]

First of all, putting a capacitor across an AC supply won't store power unless it's got a rectifier built in. If it has, then that power will be released as DC, which won't run the AC motor in an electrical appliance. Secondly, it's obvious that if the device were storing energy at the same time as using it, the rate of power usage increases. So in that respect, the description of how the device works is pure garbage.

However, there's one possible real effect to consider, because the garbage description is very specific about the importance of electric motors. Electric motors give a primarily inductive loading on the AC power supply, i.e. a positive reactance, whereas the capacitor will give a negative reactance. Balancing the two could conceivably give a purely resistive load, with a lower absolute impedance, so that the current drawn is much lower (though the power dissipated is the same). If the electricity meter only measures current, then running an electric motor will draw less power (because its load is primarily reactive) than a simple current x voltage calculation suggests.

What I suspect this device may actually do, therefore, is monitor the phase relationship between the supply voltage and current, and add a variable capacitive load to null the phase difference. In effect, rather than reducing the energy consumption of the household, it negates any overestimates of that energy consumption due to an oversimplified measuring method. In that respect, it's possible that it gives a real reduction in energy bills; in effect, it's keeping the electricity company honest.

I may be wrong about all this, because I'm drawing on stuff I learned at high school, a long time ago in a galaxy far, far away. Maybe someone whose electrical engineering expertise is a little more up-to-date could comment.

Dave

 

[BenBurch]

Could you use such a device to prevent the proper functioning of the electric meter? In other words, might it be a way to cheat the power company rather than a device to increase efficiency.

But yeah, if the meter is not being interfered with, then all it does is store electricity already on your side of the meter.

 

[Christian Klippel]

Hello,

keep in mind that there is a thing called power factor. A regular electricity meter in the average home is optimized to measure a load at a power factor of 1. The more the load deviates from that, the less the meter does count. A pure resistive load has a power factor of 1, while a pure capacitive or inductive load has a power factor of zero.

In other words: if you hook an ac capacitor to the ac line, the meter would almost not register it at all. While the cap is definitely recharged at each cycle, and thus consuming energy, the meter just does not register it. However, as others have pointed out, to effectively _store_ energy in the cap for later use, it has to be rectified first, and thus released as dc.

If you look at fluorescent lamps, the regular ones with a regular inductive ballast, you will notice that there is also a capacitor. That cap is used to correct the power factor of the inductive ballast. If you take the cap out, your meter will go slower. The energy is still consumed, just that it is not registered properly anymore. In German it is called "Blindleistung", which describes it pretty well: The meter is blind to the power, thus it does not see it. However, your cabling will still heat up while transporting that power.

If you look at curve traces for the voltage and current for a load, with a resistive load the curves overlay each other, that is, at the peak of the voltage you also have the peak of the current. For a pure inductive load, the voltage trace leads the current trace by a quarter period, in case of a pure capacitor, the current trace leads the voltage trace by a quarter period. Now, if you put the pure inductive load plus the pure capacitive load together on the line, it will behave as a pure resistive load, thus the current and voltage traces match again. That is called compensation and that is what is done in the fluoroescent lamp armature.

However, if you intend to rip out all the cap's in your fluoros, be warned that there is indeed a way to measure that power, and if the electricity company finds out what you are up to, you're heading into trouble. Industrial sites are often checked for that stuff, and if in doubt, there will be special meter installed that captures the power-consumption of these kinds of loads.

So, in theory such a device as proposed in the OP _may_ have an (minute) effect on the regular meter, by simply shifting the overall power factor away from 1 towards 0. However, it would _not_ actually save energy (or reduce its usage, for that matter), instead it would actually use _more_ energy due to the added cap's and stuff, just that it tricks the meter to register less.

Greetings,

Chris

Edit: I wrote "...the meter would almost not register..." because we live in the real world, which is not perfect. Thus, we don't have perfect capacitive or inductive loads, and would never reach a power factor of 0 in reality. Every real-world capacitor has a small inductance, as well as each inductor will have a small capacitance.

 

[MattusMaximus]

Upon further analysis, it seems that power-factor boosting is the trick behind this device. I did a Google search for the "Power Save 1200" unit advertised at www.FreeEasyGreen.com and found another company which sells exactly the same device. This other company is called "Power Save" (http://www.power-save.com/1200.html), and the description is identical...

The Power-Save 1200™ is a small gray box that fits neatly next to your breaker panel, saves you money year after year and protects the entire home. The Power-Save 1200™ was designed with the homeowner in mind, providing lower energy bills, increased motor and appliance life, for all of the equipment inside of your house.

Now, I did find an FAQ at the Power Save website which gave a description of what the Power Save 1200 is supposed to do, and it does seem to be this inductance-capacitance trick with the power factor... http://www.power-save.com/faqs.html

How Does the Power-Save Unit Work?
The Power-Save reduces the amount of power drawn from the utility by storing (in its capacitors) otherwise lost electricity (watts) caused by the inductive motors in your home. (Some examples of inductive motors are Air Conditioning units, refrigerators, freezers, washers, dryers, dishwashers, pool pumps, vacuum cleaners, furnace blower motors, fans etc.) The technology applied by the Power-Save 1200™ Unit supplies that stored electricity back to your inductive loads, thus causing you to decrease your demand from the utility. If you decrease your demand from the utility, your meter slows down, and you use less electricity. The thought is, you’ve already paid for that electricity, why pay for it and waste it when you can pay for it, store it, and reuse it again. This whole process is called power factor optimization.

What is Power Factor?
Power factor is the percentage of electricity that’s delivered to your house and used effectively, compared to what is wasted. For example, a 1.0 power factor means that all the electricity that’s being delivered to your home is being used effectively for its purpose. However, most homes in America today have a .77 power factor or less. This means that 77% of the electricity that is coming thru your meter at your home or business is being used effectively, the other 23% is being wasted by your inductive load. With a low power factor, the utility has to deliver more electricity to do the same work. However, the Power-Save unit increases that power factor in most cases to .97 or .98, thus increasing the effective use of your electricity and lowering your usage.

Now, seeing this new info, I will revise my earlier suspicion that this was a "free-energy" device. However, I have to wonder about the validity of the claims that the power factor can be boosted from 0.77 to 0.97 or higher. If this were the real thing, wouldn't it already be all over the place, especially in light of how energy costs soared over the last few years? It still seems very suspect to me - almost like a "close-to-free-energy-but-not-quite" device.

Whoever put together that original website doesn't seem to be using the correct terminology, and that's a warning sign right there.

 

[MattusMaximus]

Okay, I'm really beginning to think this is a bogus thing now. Not "free-energy", but it is starting to smell bad. The more I look, the more get-green-quick websites I keep finding regarding this PS1200 unit. Here's another one - http://hotwattsolar.com/Power-Save-1200.php
And I keep seeing the same (or almost identical) text over and over again...

The Power-Save 1200™ is a small gray box that fits neatly next to your breaker panel, saves you money year after year and protects the entire home. The Power-Save 1200™ was designed with the homeowner in mind, providing lower energy bills, increased motor and appliance life, for all of the equipment inside of your house.

I smell a scam, folks.

 

[Christian Klippel]

However, I have to wonder about the validity of the claims that the power factor can be boosted from 0.77 to 0.97 or higher. If this were the real thing, wouldn't it already be all over the place, especially in light of how energy costs soared over the last few years?

Hi MattusMaximus,

and exactly that is the problem. If your home (that is, all loads in your home combined) had an power-factor of 0.77, and you would install something that increases it to 0.97, your electricity meter would actually register _more_. For this thing to have the advertised effect, it has to _decrease_ the power factor, that is, going from 0.77 to 0.57 or so.

Again, a regular electro-mechanic electricity meter (called "Ferraris Zähler" in German) is built to work best at a power factor of 1. Anything below that will make the meter register less. From what i know, this kind of meter is still the most commonly used one around the world.

If this thing really increases the power factor, that would mean that whoever uses it would actually pay more, because it makes the meter to register more.

You can check that yourself quite easy. Get a bunch (10 or 20 or so) of fluorescent armatures (the good old ones using an inductive ballast and that have a capacitor installed), wire them in parallel. Take one of these meters to measure the consumption. Connect it all, put lamps in and turn it on. Let it run for some hours or a day, and make a note of the reading. Now remove all capacitors in the armatures and let it run again for the same time, compare the readings.

Greetings,

Chris

 

[Dilb]

The idea of this device is that your power meter might be designed to measure the current you draw, not the actual power. Assuming you use a constant amount of real power, you draw larger and larger currents as your power factor decreases. Since the power company actually needs to supply that current, and it contributes to losses, a low power factor is a bad thing.

I would have thought that modern meters wouldn't have this problem, but the last section would seem to say that isn't the case for Ontario, and you do get billed based on current. So I guess it might save you money, but check with your power company first.

 

[Careyp74]

Hi MattusMaximus,

You can check that yourself quite easy. Get a bunch (10 or 20 or so) of fluorescent armatures (the good old ones using an inductive ballast and that have a capacitor installed), wire them in parallel. Take one of these meters to measure the consumption. Connect it all, put lamps in and turn it on. Let it run for some hours or a day, and make a note of the reading. Now remove all capacitors in the armatures and let it run again for the same time, compare the readings.

I was under the assumption that the cap supplied a higher voltage when the light switch is first turned on because it takes a higher voltage to start then it does to run. After that, it is using more electricity being there due to heat loss.

 

[Christian Klippel]

Hello Dilb,

indeed, that might be the case in that situation.

Would be interresting to know what kind of meters are used throughout the world. Here in Germany it is the electro-mechanical type (Ferranti). It is used almost everywhere here, for industrial sites, houses and homes, 1 phase or 3 phase supply. Only in rare occasions people get a electronic meter, specially designed to handle loads with a low power factor. But usually these get only installed if there seems to be something suspect, or if there is good reason to believe that the loads have a low power factor.

From what i know, the same type of meters are used in Switzerland, Spain and France.

What type meter do you and others have? Here's the ones we have (sorry, German Wikipedia only): de.wikipedia.org/wiki/Ferraris-Zähler

Greetings,

Chris

 

[pchams]

Ontario Hydro used to give discounts to industry which would install capacitor banks for correcting phase angle (power factor).
They may still do this.

 

[Christian Klippel]

I was under the assumption that the cap supplied a higher voltage when the light switch is first turned on because it takes a higher voltage to start then it does to run. After that, it is using more electricity being there due to heat loss.

Hi Careyp,

no. That is what the combination of inductive ballast and the starter does. You turn on the power, but the lamp does not light up (no current flows through it), so the bimetall in the starter's "glow-discharge lamp" will bend and close the circuit. This circuit is the ballast in series with the cathode's filaments. That causes the filaments to heat up. Now the starter re-opens which produces an inductive kickback in the ballast, which in turn "ignites" the lamp. That kickback has a much higher voltage then, of course. Once the lamp is ignited, current flows through it, limited by the ballast. Since the current path is through the lamp, the starter (which is parallel to the lamp) is idling.

See en.wikipedia.org/wiki/Fluorescent_lamp#Starting

A nice pictured sequence of the starting process can be seen in the german wikipedia: de.wikipedia.org/wiki/Leuchtstofflampe#Startvorgang

As you can see, no capacitor is needed to start the lamp.

Note that there is a small capacitor in the starter as well, but that is not the one i am referring to. I mean the big one in the armature.

Greetings,

Chris

 

[casebro]

But, all the newer motors/appliances use capacitors in the motors already. And, even the motors without caps act as if they do, since there is a capacitance to all those copper windings. Plus, all those appliances have caps that are balanced to the load on the motor, adding more capacitance is likely to screw up the motor life. Nothing to gain here, move along...

Remember the little discs you could put in the socket under your light bulb? They were diodes, making the ac into dc, and saving electricity. But making the bulbs dimmer, they did nothing that going to dimmer bulbs wouldn't do.

 

[Christian Klippel]

Remember the little discs you could put in the socket under your light bulb? They were diodes, making the ac into dc, and saving electricity. But making the bulbs dimmer, they did nothing that going to dimmer bulbs wouldn't do.

Hello casebro,

well, while putting a diode in series to a normal light bulb makes it dimmer, it also extends the life of the bulb. I think that is the main reason why they were put on market, at least here in Germany.

I used to have a small light outside my home which was on 24/7. It used a simple diode in series, and the bulb lasted over 6 years while in continuous operation. The reason i had to change it was actually because i smashed it by accident. Sure, this is only an anectode, just wanted to tell.

As for the motors, yes they do have cap's built in. But these are mostly to reduce EMI and to "kill" the sparks at the commutator. The motor itself doesnt care (in means of lifetime) if there are additional capacitors. If it would, you'd better unplug all loads that have a big capacitive component before using your vacuum cleaner

In any case, i doubt that the OP's device has any useful effect on the average. There might be rare occasions where it helps, due to fiddling with the power factor, if the energy meter installed is made to capture low power factor loads. With the simple, electro-mechanic meters i suspect that you actually get higher bills at the end of the month, if it really increases the power-factor seen by the meter.

Sorry for the derail,

Chris

 

[Dilb]

well, while putting a diode in series to a normal light bulb makes it dimmer, it also extends the life of the bulb. I think that is the main reason why they were put on market, at least here in Germany.

I used to have a small light outside my home which was on 24/7. It used a simple diode in series, and the bulb lasted over 6 years while in continuous operation. The reason i had to change it was actually because i smashed it by accident. Sure, this is only an anectode, just wanted to tell.

Sure it will extend the life of the bulb, it'll also cause the efficiency to plummet, as less power is converted to radiation, and the peak radiation frequency moves further towards infrared. You can do a similar thing by running bulbs designed for 220V at 120V. Alternatively you (assuming you can manufacture light bulbs, anyway) could just use a thicker tungsten wire, like the oldest light bulb in the world.

I guess longevity might have been the idea, but it doesn't strike me as a particularly great way to do it.

 

[Almo]

2. The Power Save unit reduces the amount of electricity drawn from the utility company by storing some of the electricity in it's capacitor

If they can't even get their grammar right, I wouldn't even begin to trust them as a reputable company.

 

[Thabiguy]

Okay, some clarification is in order.

The power factor is the ratio of real power (the energy consumed by your home appliances) and apparent power (which can be approximately visualized as energy transferred over the wires).

Question #1: How can you consume less energy than has been transferred over the wires? - It works like this: during one part of the phase cycle, the energy is stored, and during another part, it is returned to the source. So it travels over the wires, but doesn't perform any useful work.

Question #2: If the energy is returned to the source, why does the power company even care? - Because even though you didn't consume that energy, it still had to be produced and transferred (in vain), resulting in real distribution losses along the way (needlessly heating up the wires). Your inefficient way of energy consumption is costing the power company money.

Question #3: How does the power company deal with that? - In some places (where I live, for example), you are charged for real power (kWh consumed) and you are required to keep your power factor high enough. If you fail to do that, you may be penalized. - In other areas, I hear, some power companies charge for apparent power (kVAh transferred). This obviously motivates the customer to keep their power factor high, but is quite unfair, effectively allowing the power company to sell the "paid for but unconsumed energy" to another customer, earning them significantly more money than the distribution losses cost them.


With all this in mind, I have a few remarks to what has been said.

A pure resistive load has a power factor of 1, while a pure capacitive or inductive load has a power factor of zero.

A load with a power factor of zero does no useful work, by definition.

If you look at fluorescent lamps, the regular ones with a regular inductive ballast, you will notice that there is also a capacitor. That cap is used to correct the power factor of the inductive ballast. If you take the cap out, your meter will go slower.

No, it won't. Doing that will increase the power factor by increasing the apparent power. If your meter measures real power, it will stay the same (but the power company will dislike you). If your meter measures apparent power, it will go faster (and the power company will love you).

The energy is still consumed, just that it is not registered properly anymore.

That energy is not consumed, it is returned to the source. If it were consumed, it would constitute real power, and the power factor would not change. But that is not the case.

So, in theory such a device as proposed in the OP _may_ have an (minute) effect on the regular meter, by simply shifting the overall power factor away from 1 towards 0. However, it would _not_ actually save energy (or reduce its usage, for that matter), instead it would actually use _more_ energy due to the added cap's and stuff, just that it tricks the meter to register less.

Again, the power factor is the ratio of the real power and the apparent power. No trick will decrease the real power consumed by the appliance (unless you actually make the appliance do less work). The only way to decrease the power factor, without reducing the consumed power, is to increase apparent power, and you can certainly do that. But doing this will not trick the meter to register less. It will register either the same power consumption or more, depending on what it measures.

As for the device in the OP, it is apparently a power factor correction unit (this is what this kind of devices is called). It is potentially useful to small-scale customers whom the power company unfairly charges for apparent power. And of course, they're important for large-scale customers, but these have been using such units for ages.

 

[ktesibios]

Thabigguy has gotten everything pretty much right- the first person on the thread to accomplish this. I just have a few observations:

The classic electromechanical watt-hour meter (the thing with the spinning disc) used by electric utilities is basically a motor in which the rotational speed of the disc is proportional to the product of the current through the current-sensing coils, which are connected in series with the incoming line and the voltage across the voltage-sensing coils, which are connected across the incoming line. The result is that the disc rotates at a speed proportional to the true power; the dials which the meter-reader checks count up the number of rotations via a gear train. These meters read most accurately for a load power factor of unity, but if properly calibrated they won't run at all if the load is purely reactive (0 power factor).

The newer electronic meters most likely work by sampling and quantizing the current-sense and voltage-sense signals (like the front end of a digital audio recording system), multiplying the two and integrating the product over time. This will also result in a meter which responds to true power and not imaginary power. You could also do this by using analog multiplication and then digitizing the product signal and integrating it.

Electric companies have a good reason for getting upset if customers' loads have low power factors. They're not getting paid to deliver VARS (volt-amperes reactive) but every ampere of reactive current that flows in their transmission and distribution lines costs them money by dissipating power in the resistance of the line. That's more of a consideration for large-scale users like factories than for individual residential customers.

There is a way in which electric companies do charge customers on the basis of simple current draw: the kw-h meters installed at commercial accounts commonly have a "demand" feature. This is a scale that indicates the raw current draw and holds the highest reading until it's manually reset by the meter reader. If your peak demand in a given month exceeds a preset threshold, you'll pay a surcharge on your next bill, for making life more difficult for the people who are trying to keep the distribution network working efficiently for everybody.

 

[BillC]

Thabiguy and ktesibios have it between them. An additional reason why electricity utilities wish to manage their reactive flows is the effect these have on system voltages. Excessively inductive loads result in low system volts, excessively capactive loads give high voltages.