Energy Saving Via P.f. Control ?

[Techfan]

First of all, thanks to Internet , thanks to the creator of this forum , thanks to god/LUCK for making me come here accidentally and lastly thanks (in anticipation) to all the tech.guys who can help me out with my quarry, which I know otherwise might have remained unsolved. (By the way, I am from India.)

 

I bought a ENERGY SAVER device for up to 15KW load, from China, made with some German technology. It's a sealed unit which may be having a capacitor for sure. Anyway, it claims to reduce electricity bills by 50%, besides of course our benefits like surge protection, stabilize electric current, reduce electrical heating, prolongs life of appliances and saves energy efficiently etc etc.

 

http://www.made-in-china.com/china-product...er-FL-001-.html

 

I tested it on various loads in parallel to the device ,with a clamp meter and got the following results :

 

 

1. Current drawn by fridge before = 1 amp. / After device in-parallel = 0.6 amp.(40%)

2. By tube light = 0.3 amp. / After = 0.1 amp. (66%)

3. Table fan = 0.5 amp. / After = 0.3 amp.(40%)

4. AC = reduction very less or not clear.

 

But it did not show any difference before or after on Washing machine, Air-cooler etc, which did intrigue me a bit but I thought it is because both already have a condenser attached to them. But the shocking part was when the current consumption by the sealing-fan, instead of decreasing (or at least even remaining constant), it in fact increased by 20% !!!

 

Now by this I am totally confused (and sad at my purchase, as I wished I would do a business of this).

 

Now my questions to the experienced guys here on this and related subject are :

 

1. Does this device not work on already condenser attached appliances ?

2. Why is there an increase in current consumption, by the sealing-fan ?

3. Is the massive reduction of current to fridge and tube light, is then only an eye-wash, as at the end all appliances will average out in terms of overall current consumption ?

 

[because when I attach the clamp meter to the main meter's phase wire and switch all the various loads, I get only an average 15%-20% reduction at the most. However, when only the fridge is ON, I get a reduction of 35% at the meter too (is the rest 5%lost in the wires?).]

 

4. Most importantly, does the reduction of 40% in fridge, reduce the POWER CONSUMPTION at the meter by 40% ALSO ? i.e. will my bill DUE TO THE FRIDGE ALONE, reduce by 40% or is it all differ net. I mean CURRENT REDUCTION IS DIFFERENT, to the reduction of actual wattage ? OR will the device work to actually reduce my bills, even though it maybe an average of, say, 15-20% only ???

 

5. So, on what kind of domestic or industrial machines and appliances do such devices work ? So, that I can still think of a business with this otherwise fantastic device/technology (as far as the fridge and tube lights are concerned) ? Also, in industries P.F. correction is a known fact and required badly by the industry too. This is the first time (at least for India, that a device up to 15KW load has come-in for domestic loads, where the concept of power factor correction does not exist at all).

 

The device is sold here by making a false claim of 50% by showing the current reduction on a tube light alone. God only knows, what happens finally when all the load is switched ON ? I got this doubt more, as when sealing fan was ON, the current in fact increased !!!

 

So, kindly someone explain the above points raised by me. WILL IT BE MORALLY AND TECHNICALLY RIGHT TO SELL THIS DEVICE to others ? OR, will it at least reduce 15% ? OR none at all ? OR on "particular", inductive domestic/industrial loads only ? I am very confused, kindly help ? Do I have a really nice and new technology at hand or is it all a fake ? Although, in industries, PF correction is a big big issue.

 

Waiting for a detailed guidance by all aware guys here and once again, thanks in anticipation.

 

 

 

 

 

 

 

 

 

 

[jraef]

First off, please don't cross post. Most of us look at the "View New Posts" link at the upper right side of your page (once you have registered) so there is no need to post in more than one forum.

 

No, your secondary instinct was correct, these devices do not save energy in any appreciable way. Tool bad you didn't trust that instinct before making the purchase...

 

In a nutshell, they do reduce the CURRENT (Amps) in unloaded induction applications like motors and ballasts, but what they don't tell you is that you are not billed on Amps, you are billed on kWh and these devices do NOT reduce the kW, so they therefore do not reduce the kWh either. The concept is confusing to most non-EEs and that is the very fact that they are preying upon. People can clamp a meter on and see the needle go down, but they rarely understand that their utility doesn't use that needle when deciding how much to charge you, so you end up paying the same. If you look through some of the older threads in this forum you will see several on this very subject that will go into more of the engineering details as to why this is.

 

Yes, Power Factor is something that industrial users must be concerned with, but that is only because the utilities have to contend with the losses associated with poor power factor, so thjey penalize industrial and large commercial users for having it too low. Poor power factor means additional losses in the transmission and distribution equipment, i.e. the power lines and transformers owned by the utilities. That's because they must have equipment capable of supplying ALL of the power to the users, but can only bill them for the power doing the actual work, the kW. The other Amps, as you witnessed, are just enabling the motors to be ready to do work by magnetizing the windings, but do not contribute to the overall kW as seen by the meter. Utilities don't really bother billing residential users for this power because residences make up a very small portion of the load they must supply. Metering, billing and collecting power factor penalties would not be worth doing in residential applications. That's why these types of products are basically a scam.

 

Is it unethical? You bet it is! Does that stop people from doing it? Has ethics ever stopped everyone from doing things that exploit others? It stops some of us, but there are always those in any society who thrive on exploitation and these people fit that description. In some countries, such as the US, there are government entities who eventually get around to putting and end to false claims on products like that, but in the years it takes them to act, the purveyors manage to skim a healthy chunk off the top. Then they simply fold up and restart under a new name. In China, there are little or no checks and balances at this point, so that has become a haven for this sort of thing.

 

Remember, if it looks too good to be true, it probably is.

[marke]

Hello Techfan

Welcome to the forum

 

Yes, it certainly looks like it is a power factor correction capacitor.

There are several discussions about the use of PFC on domestic installations on this site, but the bottom line is that I have never seen a power factor penalty applied to a domestic installation, and the power is charged for KW, not Amps, so there is no advantage and no payback.

 

As a matter of interest, disconnect all other load and connect the device and you will measure an increase in current flow due to the capacitive current!!

 

To determine if there is any benefit on your KWHr meter, connect a fixed load and time the rotation of the disk, then connect the capacitor and re time the disk rotation. If the disk is turning slower, you have a saving.

 

Best regards,

[AB2005]

Hello Techfan

 

This type of topic has already discussed in this forum. As Marke suggested to you, you should check the rpm of your energy meter disc before and after connecting the device. You would see that there would no energy saving by doing so.

 

[Techfan]

Hello Mr. jraef, (firstly sorry about the cross post, as I was too keen to see to it that max. no. of guys advice me but dint know this 'view new post thing'.)

 

Next, I cannot thank you enough to enlighten me about the incredible scam going on in the name of energy saving ,environment friendly, appliance life increasing etc etc device !!! And this scam has started in India from Nov.2007, from the capital city of New Delhi and by this time thousands of guys must be duped !!!

 

They are selling the device here at 4 times the China MRP !!! I myself bought another 25 pieces to start a business myself, but I am in a shock myself and have written to the co. to refund me. Let's what happens.

 

But then, please tell me a few things more please :

 

1. Will this device not work at all, "IN TERMS OF KWHr SAVINGS" in any any inductive load at all ? Like a fridge and tube-lights, where the current reduction to these loads is very high, to the tune of 40-60% !!! Even industrial application it will not work ? So, it means, even in industries the PF correction is mandated for "other reasons", not for KWHr savings ? Yes ? Is it so ?

 

2. Also, in industries, what kind of (up-to) 15 KW loads require P.F. correction ? At least there I can introduce this device.

 

3. Likewise, is there any device which will reduce the POWER CONSUMPTION of an A.C.? Or even here, all said and done, an A.C. will consume the amount of power it is designed to consume? As, there are again similar kind of devices, promising to be Power savers for A.C.

 

[ 4. Alternatively, where can I get a circuit for a TIMER DEVICE for a 2.0 T A.C. which will switch-ON the A.C. for 15 mins.(or 30/60 mins.) and then switch it OFF for the same time, thus obviously saving real power. Is it not ? Where's the right circuit for the same ? ]

 

Lastly, kindly guide me as to where can I introduce this device, as it is off-course improving the P.F.(i.e. efficiency ?) of the purely inductive loads, up-to 15 KWs. So, where can it be technically/ethically be introduced.

 

THANKS A LOT.

 

(Next, hello Marke and AB2005, yes, I had gone through all the answers of the forum on my questions, still there was a keen desire to further more specifically to my needs. Thanks for your advice and tell me despite all NEGATIVE views, should I still be tempted to test the device, this time by using the main-meter reading method to see if " actual wattage consumption " is reducing by this device or not ? Should I ? As otherwise it would mean, all other guys are still skeptical about saying that actual KWHr. savings do not occur.)

[marke]

Hello Techfan

 

1.) Power factor correction will not alter the KWHrs drawn by an appliance. It can reduce the losses in the supply system, but this will not register on your supply meter.

Large users pay power factor penalties if their power factor is poor. These levies are applied to encourage an improvement in power factor as this reduces distribution losses and allows greater utilisation of distribution equipment. The KWHrs are not affected. For example, if you have a 750KVA transformer and a power factor of 1.0, you can load it up to 750KW. If the power factor is 0.5, you can only load it up to 375KW - lower utilization of the transformer.

 

2) Industrial loads are generally three phase. Industrial power factor correction equipment is three phase. Your "device" is single phase so would have little if any use in the industrial market.

 

3) To reduce the power consumption, you have to either reduce the amount of work done, (output power), or increase the efficiency of the equipment or system. AC systems are usually thermostatically controlled, so the operation is self regulating. Modern systems use variable speed controllers to reduce the speed to reduce the system losses, lower speed, lower friction, lower losses.

 

Best regards,

[Techfan]

Hello Marke, thanks for a wonderful ex. of a transformer not getting loaded. So, in a quest to get into this field roughly, can I have chance to tell pvt. housing colony or commercial complexes about this ex. and then maybe they need P.F. cocrrection, ofcoure not for as low as 15KW and single Phase.

Also, more importantly, what about generators ? The same Problem of loading occurs in generators too ? As, when there is no supply, they act as defacto transformer for the clints ?

 

Thanks and regards.

 

[Techfan]

Hi all, I found one application in India by a city's Municipal corporation for the P.F. correction.

Can someone tell me if it will work here OR is it that they have also got it all wrong ? Or is the Municipality's perception wrong ?

 

http://www.hinduonnet.com/2005/12/12/stori...21216580100.htm

 

Marke, your comments sought again Pl. for this Perticular application of S.V. lamps.

Regards and Thanks.

[kens]

Hi Techfan,

 

"The device, according to director (technical) of the company P. Pavan Kumar, will have a micro-controller timer that allows lights to be switched on and switched off at a particular time, thus saving some power."

 

Switching things off saves power.

 

I would also like some tests on the light output from the lamps.

 

Ken

[jraef]

The power factor - an important indicator of the effect of the load current on the efficiency of the supply system - also gets increased resulting in less power consumption.

 

Maybe it's just the writer of the article, but that points to a misunderstanding of power consumption.

 

What a lot of lighting energy savers do is just reduce the voltage, which does reduce the power consumption, as well as the light output. They are probably not noticing the lumen reduction, so they are happy. If you had a 70W HPS light and you managed to reduce the power consumption to 65W, the lumen output might be only barely noticeable, but you have saved 8% of your energy right there.

[kens]

I agree with jraef regarding the lighting energy savers, in many cases there are legitimate uses of voltage reduction technology to save energy in lighting applications, however there is always a reduction in light output. In many cases this is acceptable. An example maybe a multi story carpark that does not require the full lightoutput during day but does during the night, or a warehouse with similar condtions. The important thing is that the loss in light out put is understood and accepted. In any case where promises are made to reduce the input energy without reducing the output of a device there needs to be a careful study made of the claims made.

 

Ken

[Techfan]

Hello all, in my relentless quest to find an answer to bill reduction via P.F. correction I stumbled upon this report. Kindly comment.

 

POWER QUALITY GUIDELINES FOR

ENERGY-EFFICIENT DEVICE

APPLICATION

Prepared For:

California Energy Commission

Public Interest Energy Research Program

Prepared By:

Electric Power Research Institute

CONSULTANT REPORT

January 2003

500-03-073C

 

Evaluating the Energy-Saving Potential From Non-Traditional Measures

 

Capacitor Benefit #2: Release of Electrical System Capacity and Voltage

Regulation Improvement

 

Utilities practice the same principles as their customers when they install shunt capacitor banks. The capacitors provide the reactive power required by the power system (including customer loads). The cumulative effects of several customers with low power factors can significantly increase the apparent power load on the system. Installing capacitor banks allows the utility to increase the number of customers that can be serviced through their existing distribution and transmission systems.

The same principles hold true inside the customer’s own facility. Lowering the apparent power required to service loads within the facility frees up capacity to expand and service new loads without the need to increase the current capacity of the existing electrical infrastructure. Capacitors also have the added benefit of improving voltage regulation throughout the power system. Utilities install capacitors at specific locations within the system to increase the voltage at a specific point in the power system. The reactive support provided by the capacitors helps to reduce voltage drop. Lowering of the apparent power reduces system current levels and reduces system voltage drop. Capacitors installed within a customer’s facility also have the same effect.

However, in industrial and commercial facilities, the installation of capacitors is not usually justifiable on the basis of system voltage rise alone.

 

Capacitor Benefit #3: Reduction of Electrical System Losses

 

The lowering of electrical system losses and the increase of system efficiency through the use of shunt capacitor banks is primarily the result of lower conductor losses. The real power (kW) losses in an electrical conductor are a function of the current flowing through the conductor and the resistance of the conductor. The conductor losses are directly proportional to the square of the current flowing through the conductor (Ploss = I2R). Lowering the apparent power demand of the load will decrease the current flowing through the power conductors that service a load, resulting in a lower real power demand from the power system.

 

Capacitor Benefit #4: Potential Energy Savings

By reducing reactive current, capacitors have the potential to provide modest energy savings in facility wiring systems. To achieve these savings, capacitors must be installed as close as possible to loads with low power factor. Based on the system power factor before and after the installation of power-factor-correcting-capacitors, Equation 5-1 shows the formula for computing the percent reduction in real power losses for a given system.

 

% Loss Reduction = 100 [ 1 – square of( pf old / pf new ) ]

 

Equation 5-1

For example, with an old power factor of 0.7 and a new power factor of 0.9, the system losses due to reactive current can be reduced by nearly 40 percent. While this may seem a large percent savings, the absolute amount of energy saved depends on how much energy was lost in facility wiring to begin with. Figure 5-3 shows the reduction in system losses the capacitors provided the power system supplying this motor. Please note that the values in Figure 5-3 are based on percentages and not on the real power (kW) savings. To accurately assess the real power or Kw savings, actual values of system resistance and current measurements taken before and after the application of the capacitors would be required.

 

Typically, in an industrial or commercial facility, energy losses because of I2R heating in intra facility conductors are, at most, 1-2 percent of total facility load. Error! Reference source not found. shows the loss reduction as a percent of total facility load for power factor improvement

(at the load) from original 0.6 to 0.7, 0.8, 0.9, and 0.95. The figure is based on the assumption that system losses attributable to reduced power factor are 2 percent of total facility load and the power factor improvement scheme is implemented at the load to gain maximum advantage of loss reduction. For most facilities, overall energy savings of more than 0.5 percent from power factor would be a significant accomplishment.

 

**********************

 

NOW, does this all mean a reduction of even at least 10 % of our domestic electric bills ??? Thanks all.

[marke]

Hello Techfan

 

The domestic power bill is typically based on KWHr usage only, therefore there will only be a reduction in your power bill if you reduce KWHr.

 

Power factor correction reduces reactive current from flowing in the supply. This reduction in the reactive current will reduce the losses in the supply.

Your meter does not measure the losses in the supply, only the losses between your meter and your appliances. The losses are only significant if you have a significant voltage drop between your meter and your appliance.

 

In order for your domestic power bill to be reduced by the addition of power factor correction, you must have:

1. A high level of reactive current drawn by your connected load
2. Significant voltage drop between your meter and your connected load.

Reactive currents are drawn by induction motors. I doubt that you have a significant percentage of your power being used continuously by induction motors, so I would not expect that you have a high percentage of reactive current. This can be determined by measuring the power factor.

Unless you have very long cables between your meter and your appliances, and undersized cables, I would not expect you to have significant voltage drop.

Bottom line, I have never seen a domestic installation that would benefit from the addition of power factor correction capacitors. Hence, the power utilities do not measure the power factor, or maximum demand KVA. There is no pf penalty on domestic installations. If there was the potential to save energy, they would definitely be monitoring and charging.

 

Best regards,

[kens]

 

NOW, does this all mean a reduction of even at least 10 % of our domestic electric bills ??? Thanks all.

NO

 

 

Hello all, in my relentless quest to find an answer to bill reduction via P.F. correction I stumbled upon this report. Kindly comment.

 

You are indeed relentless , you would be better off looking into proven efficiency measures that will reduce your consumption rather than this sort of technology.

 

How old is your fridge? What do you use to heat your water? What temperature is your hot water set at? Is you house well insulated?

 

There is no majic cure unfortunatly.

 

Ken

[Techfan]

Hello Ken, thanks first of all for appreciating(?) my relentlessness...

 

On the flip side I am also now beginning to look for alternate means to save energy and have come across one product (which I will share with you too) and one product idea (which I wish to seek help about, from you all).

1. The 1st product is via a manufacturer in India, who has developed an excellent reflective material in the form of an 8mm film, for THERMAL INSULATION, so that there is a marked difference of UPTO 20 degrees, between the TOP and BOTTOM of a roof slab, factory sheds, and all the A.C. DUCTS etc.

 

Against radiation, this film has ALUMINUM FOIL.

Against conduction, this film has Air packed Polythene BUBBLE FILM and

Against Convection, it has Aluminum Foil with Bubble film and WHITE POLY.

 

It also provides excellent water proofing in turn, to the concrete slabs.

 

So, with this film, costing around Rs. 30 /- (or 0.75 $) per square ft, we can INSTIGATE the AC's thermostat to activate much earlier than in a normal heated room, as it's slab will be backed without the film.

So, if, without this reflective coating an AC runs for 5 hours, for a certain set temperature, it runs for 2 hours only when this film is set up.

 

Thus, AC POWER IS SAVED !!!

 

2. Secondly, I propose to use an "AUTOMATIC CYCLIC TIMER" which will switch OFF an A.C. for say, 15/30 minutes and the switch it ON for the next duration. This way for an entire run of 10 hours of an A.C. bill will be only for 5 hours. In India specially, power woes are more pronounced !!!

 

Can someone please tell me from which website will I get such a circuit of 555 kinds, which can handle high 10A kinf of currents of an A.C. ?

 

(Also, Dear marke and all, is there a similar forum for Electronics related issues ?)

 

And thanks everyone, for relentlessly answering my "P.F. v/s DOMESTIC-BILL REDUCTION" quarries.

Actually, I want to get deeper into the fact that how SO MANY people are selling this device from China, in the domestic circuit "ALSO", just by showing a reduced current in the clamp meter ??? My first reaction was, wow, money earning is SO VERY easy....???

 

My final question to Marke,

'You have mentioned about Induction motors as an example above, so if this P.F. device is placed close to an Induction motor of 15 KW load (used in whatever Industrial or domestic application), will there be any "BILL" related benefit to the user ? OR NO ? FINALLY, NO ??? Or is there's any other benefit like spike buster advantage or relative cooling of the motor coils etc etc ?

Or if I may ask it in other way, In what industrial application can this 15 kW P.F. improvement device be applicable, giving SOME benefit at least, IF NOT, "bill related" advantage ?'

Can you answer please?

 

[Out of context - Marke, isn't there a slight mistake in your very first sentence to a reply to me above, where you have used the word, KWHr "twice", it should be just once in the sentence no, as it is been 'compared' to another factor/quantity ?]

 

Bye all and regards.

 

 

[marke]

Hello Techfan

 

If you wish to save energy, then you should determine where the most energy is being wasted and concentrate on making a difference there.

If you are using Air Conditioning and believe that this is a major usage of energy, then look at how much of the effect of the AC is being wasted. One of the major issues is insulation. Heat loss and/or gain results in the AC unit working harder, so look at insulation everywhere, reduce drafts, double glaze windows makes a big difference.

Another issue is good thermostatic control so that the AC is shut down when not needed.

 

If you have good insulation and good thermostatic control, then cycling the AC unit in the way you suggest, will not achieve any improvement in efficiency, and therefore no energy saving unless you reduce the work output of the AC.

if this P.F. device is placed close to an Induction motor of 15 KW load (used in whatever Industrial or domestic application), will there be any "BILL" related benefit to the user

If the user pays for KWHr only, there will be no advantage. If the user pays a pf penalty, or a KVA maximum demand tariff, then there may be an advantage.

 

Best regards,

[energy minded]

I'm also grateful for the vast source of information this site provides from your experiences and expertise and was hoping someone could help me as well. I have been approached by a firm who offers a correction on your demand to where they will guarantee a 15%min power savings p er year or will give you a 100% of your expense refund if not satisfyed. This application is at a quck service fast food restaurant. They install capacitors on the inductive loads of all motors and compressors over 5/hp and all main distrubution panels. They also offer in writing a 15 year warranty on all equipment and will pay up to $25,000 cost for damages or repairs occured with thier equipment for each occurence during the 15 year period. They did a presentation test in showing a simulation of a small motor on the amp draw before and after when capacitor block was installed. Their was an obvious diffence. I've been trying to learn as much as I can where many have said their will be no cost savings. I'm not hear to dispute your technical theory but what I do know they shared with us two of the restaurants in the same franchise family so to speak and the same protype size building where one is averaging around 10% reduction in electrical cost from the previous year for the past three month Feb- April and the other is at around 13% for the last month having just being installed. With these buildings being a protype spec and equipment being the same and talking to the operators if they did anything different and they replied with only installing this equipment. Then I ask you what am I missing and how can this be??? What risks or downsize is their in installing induction capactiors on the motors or capacitors on the distrubtion panels. They will be adding this to the air handling units and refrigeration compressors. I would welcome your thoughts or comments.....

[marke]

Hello energy minded

 

Welcome to the forum.

Power factor correction can be a very effective way of reducing the maximum demand tariff or power factor penalty.

It is common for commercial users to be faced with either a maximum KVA demand charge, or a power factor penalty. In these cases, if motors are used, power factor correction will reduce the power bill. If the bill is based on KW only, the addition of power factor correction will not reduce the power bill.

 

In some commercial installations in New Zealand, the payback can be less than 12 months for power factor correction.

 

The power factor correction is not actually providing power savings, it is providing MDI savings and this is reflected in the power bill provided that you are penalized for MDI.

 

test in showing a simulation of a small motor on the amp draw before and after when capacitor block was installed. Their was an obvious diffence.

Power factor correction will reduce the current on induction motors by reducing the reactive current drawn from the supply. This current has no bearing on the power consumed by the motor, so although the current is reduced, the KW will stay the same. An interesting test, is to test the current flowing into the motor, measured between the capacitors and motor. You will find that the curent into the motor does not change with, or without power factor correction.

 

Best regards,

[energy minded]

Marke,

 

 

First off I would like to thank you for your response but another question comes to mind. If the power factor /demand can be improved with the capacitors then why woulldn't the motor manufacutres design this type of a device right on the motor. We continually hear power companies can keep up with demand yet we hear of no regulation or standard established by the motor manufacture. Just a thought......

[marke]

Hello energy minded

 

why wouldn't the motor manufactures design this type of a device right on the motor.

The motor manufacturers could add this to the motors in the factory, but this would increase the cost of the motor, and most users would object.

 

Many large users apply automatic bulk correction at the point of supply, rather than static correction for each motor, and Variable Frequency drives and soft starters can not be used with power factor correction connected to the motor. A good idea, but it would only apply to some motors and probably not commercially viable.

 

Government bodies internationally have put a lot of pressure on increasing the efficiency of induction motors and the average induction motor today is more efficient than designs of 20 years ago.

If you look at energy utilisation in most plants, there is far more loss in the driven load than there is in the motor, so it is better to focus on other losses than on the motor itself.

Applications such as fans and pumps can be slowed down when full demand is not required. This reduces wasted energy considerably.

 

Best regards,