Energy conservation

[gar]

090309-2146 EST

There have been many threads started about energy reduction devices and the vast majority of these devices are frauds. Namely PF correction where it will have no effect on the customer's bill.

A real and simple way to reduce energy consumption and save money is to reduce any unnecessary loads. Turn lights and other moderate power consuming devices off when not needed.

Obviously a measuring tool can be of assistance to achieve this goal.

A Google search for --- power monitor meters residential --- produced the following result and many others that I have not look at.
http://www.theenergydetective.com/what/overview.html#

I read thru the web site and on the surface it looks interesting. Their claim of 2% accuracy I might question without testing. The price seems low to produce a real high quality device. But that does not mean it may not have value.

One comment I thought was incorrect --- they referred to RMS power. I have no idea what this really means.

The system uses two current transformers, and carrier current communication to the display. All memory is at the display. Many different functions are available at the display.

So you electricians that are looking for additional products to sell may find this an area that could provide some customers with an assist to reducing their energy costs. Whether this product or a similar one is used the concept has value where PF things do not.

,

 

[dreamsville]

090309-2146 EST
One comment I thought was incorrect --- they referred to RMS power. I have no idea what this really means.

I think they mean to say average power. I don't believe the RMS value of the power represents anything useful.

The RMS values of voltage and current are useful because they can be used to calculate the average power. :smile:​

 

[Besoeker]

090309-2146 EST
A real and simple way to reduce energy consumption and save money is to reduce any unnecessary loads. Turn lights and other moderate power consuming devices off when not needed.

When not in use, cut the juice?

 

[LarryFine]

When not in use, cut the juice?

Don't be dolts; kill the volts.

 

[charlie b]

I don't think this type of thing is worth its price. If I wanted to know how much energy I am using, and in the winter with mostly electric heat I sometimes do, all I have to do is open the side door and peak at the rotating disk on the meter.

 

[weressl]

I think they mean to say average power. I don't believe the RMS value of the power represents anything useful.

The RMS values of voltage and current are useful because they can be used to calculate the average power. :smile:​

It means that the voltage and curren readings ARE RMS corrected so it measures the acutal power used, the same as the rotating disk meter would. I wonder about it's value in household use though...

 

[gar]

090310-1304 EST

A rotating disk watthour meter actually measures average instantaneous power and integrates that over time. Averaged over at least a cycle or so by the disk inertia and damping. It does not measure voltage and separately current and multiply these and a fudge factor for power factor. However, these meters usually have one voltage coil across the 240 line and two current coils. The assumption is that both voltages are about the same.

Instead of using the term "RMS power" the RMS should be left off and just use power. If they are not measuring power, then define exactly what they are measuring.

Since I have never hear of this term "RMS Power" I have now done a Google search and the result is that some non-engineers (probably lawyers) created an incorrect usage of the words RMS and power. From the following reference it was apparently done at the Federal Trade Commission.

Following is what may be a description of the origin:
http://www.n4lcd.com/RMS.pdf

Would a power monitor be useful in reducing energy consumption in a home? Certainly in some, but only if the home owner wants to make effective use of the information. In my case my wife tends to leave certain lights on when there is no need. In our bath-dressing room I have 3 6' and 2 8' Slimlines. Maybe ballpark 700 W. These get left on and forgotten many times. There are other similar cases in the house. I could easily have 3 to 5 KW on at times that are un-necessary.

In 2007 I used 17,000 KWH. If I saved 10% that would be about 1700*0.12 = $204. That would pay for a monitor such as I referenced in my previous post. In higher cost areas the saving would be much higher.

Is it realistic to save 10%, in my case I believe so. If I wanted to I could probably save much more. It is also true that many savings are possible without using any instrumentation. Why do I use a couple 200 W monitors instead of 50 W LCDs? Because I like the display. Power monitoring won't change that.

Power monitoring has its major value in providing information that helps you avoid leaving things on that do not need to be on. It is also useful to evaluate residual always on loads.

.

 

[Jraef]

I don't think this type of thing is worth its price. If I wanted to know how much energy I am using, and in the winter with mostly electric heat I sometimes do, all I have to do is open the side door and peak at the rotating disk on the meter.

But don't you get it? This is for the MTV generation who has no intention of going out the door! They want to sit in front of the TV and know how much it is costing them to do so, without having to get up...

 

[weressl]

090310-1304 EST

A rotating disk watthour meter actually measures average instantaneous power and integrates that over time. Averaged over at least a cycle or so by the disk inertia and damping. It does not measure voltage and separately current and multiply these and a fudge factor for power factor. However, these meters usually have one voltage coil across the 240 line and two current coils. The assumption is that both voltages are about the same.

Instead of using the term "RMS power" the RMS should be left off and just use power. If they are not measuring power, then define exactly what they are measuring.

Since I have never hear of this term "RMS Power" I have now done a Google search and the result is that some non-engineers (probably lawyers) created an incorrect usage of the words RMS and power. From the following reference it was apparently done at the Federal Trade Commission.

Following is what may be a description of the origin:
http://www.n4lcd.com/RMS.pdf

Would a power monitor be useful in reducing energy consumption in a home? Certainly in some, but only if the home owner wants to make effective use of the information. In my case my wife tends to leave certain lights on when there is no need. In our bath-dressing room I have 3 6' and 2 8' Slimlines. Maybe ballpark 700 W. These get left on and forgotten many times. There are other similar cases in the house. I could easily have 3 to 5 KW on at times that are un-necessary.

In 2007 I used 17,000 KWH. If I saved 10% that would be about 1700*0.12 = $204. That would pay for a monitor such as I referenced in my previous post. In higher cost areas the saving would be much higher.

Is it realistic to save 10%, in my case I believe so. If I wanted to I could probably save much more. It is also true that many savings are possible without using any instrumentation. Why do I use a couple 200 W monitors instead of 50 W LCDs? Because I like the display. Power monitoring won't change that.

Power monitoring has its major value in providing information that helps you avoid leaving things on that do not need to be on. It is also useful to evaluate residual always on loads.

.

The RMS issue on meters only came about when electronic meters were introduced. All meters employing coils and magnets already show RMS measurement.

 

[gar]

090310-1855 EST

weressl:

A coil type rotating disk watthour meter creates a torque on the disk proportional to the product of the instantaneous current to one coil and instantaneous voltage to a different coil. This torque is averaged by the mechanical system, and integrated by the number of turns of the disk.

Drag torque is provided by the magnet.

RMS represents Root Mean Square. In the rotating disk watthour meter there is no squaring done, nor is there any square root performed. The only function used from RMS is mean which is the same as saying average.

RMS should not be a modifier of power unless your goal is to provide some description of the variation of the amplitude of the power. This is clearly not the case when describing what the watthour meter does.

.

 

[dbuckley]

I don't think this type of thing is worth its price. If I wanted to know how much energy I am using, and in the winter with mostly electric heat I sometimes do, all I have to do is open the side door and peak at the rotating disk on the meter.

We've got something similar on top of our telly and its just brilliant.

In NZ we dont have any of those stinkin' equipment access rules, so my meter cabinet is behind a bush, so visiting it is not a pleasent experience.

 

[weressl]

090310-1855 EST

weressl:

A coil type rotating disk watthour meter creates a torque on the disk proportional to the product of the instantaneous current to one coil and instantaneous voltage to a different coil. This torque is averaged by the mechanical system, and integrated by the number of turns of the disk.

Drag torque is provided by the magnet.

RMS represents Root Mean Square. In the rotating disk watthour meter there is no squaring done, nor is there any square root performed. The only function used from RMS is mean which is the same as saying average.

RMS should not be a modifier of power unless your goal is to provide some description of the variation of the amplitude of the power. This is clearly not the case when describing what the watthour meter does.

.

The rotation speed is in response to the magnetic forces which are proportionate to the current and voltage. The physical phenomena takes the Ut and It values and converts it to flux and generates current and counterflux in the disk which in turn performs the repulsive force of opposing magnetic fields that results in the rotation of the disk. The generater flux is the result of the whole analog value, harmonic content, distortion and all, and no digital sampling and computation involved where the distortion sampling requires a higher level of circuitry, faster sampling and more complex algorithm.

 

[Speedskater]

I just saw a TV show on the Science Channel:
Deconstructed "Episode 17" One of the short segments was on a home power meter with an animation of how it worked.

 

[weressl]

We've got something similar on top of our telly and its just brilliant.

So how much you paid for it and how long do you think it will take to pay for it in savings?

Do you have time-of-day energy cost variances?

 

[Speedskater]

I just saw a TV show on the Science Channel:
Deconstructed "Episode 17" One of the short segments was on a home power meter with an animation of how it worked.

This show will re-run this afternoon at 4:30 PM EDST and then again in the middle of the night at 4:30 AM EDST.

 

[brian john]

Does seem inexpensive for what is offered.

I can see the benefit of dad sitting on the couch yelling at the kids shut the lights off as he watches his TED.

 

[dbuckley]

So how much you paid for it and how long do you think it will take to pay for it in savings?

Do you have time-of-day energy cost variances?

In American, about $80, and I reckon its already paid itself and then some. Just by being aware of when the KWh number was higher than expected, and wondering around to find the culprit. Its a game the whole family ends up playing.

Once you have one of these things you get obsessive about every fraction of a KWh and take action to save money right there and then. I never saw that coming when I handed over the money. Other users report similar experiences.

Dont have time of day variance, just a standard rate, but do have hot water heated overnight on (slightly) cheaper power.

 

[weressl]

In American, about $80, and I reckon its already paid itself and then some. Just by being aware of when the KWh number was higher than expected, and wondering around to find the culprit. Its a game the whole family ends up playing.[/quote]

So let me get this straight, it shows kWh not kW? That would not be really helpful in identifying the culprit unless you sit there with a stopwatch in hand.

Dont have time of day variance, just a standard rate, but do have hot water heated overnight on (slightly) cheaper power.

If it is not a separate meter for the water heater, then you indeed do have a time-of-day variance.

 

[gndrod]

Using these devices for superior energy management is like detective work. When the readout spikes up, just go around and pull the plug on whatever is running to see how much energy is reduced from the readout. It will get the TV watcher off the couch to seek and unplug. I can see where it would be a healthy form of exercise and mental challenge for the individual who is on medication. I myself use an Amprobe.

 

[gar]

090312-1352 EST

grdrod:

How do you use your Amprobe to detect that your wife left on lights or other high power consumption devices in some remote part of the house?

From Wikipedia:
http://en.wikipedia.org/wiki/Leap_year

By this rule, the average number of days per year will be 365 + 1/4 − 1/100 + 1/400 = 365.2425, which is 365 days, 5 hours, 49 minutes, and 12 seconds.

A residual load of 100 W is 24*365.2425*100/1000 = 876.58 KWH/year. At my rate that is 876.58*about 0.12 = $105/year. There are many people that run way over this residual level. The Amprode method is OK to evaluate individual loads, but not much use for my wife problem, or me for that matter with things left on that do not need to be on.

As I recall my residual is in the 100 W range and that is 1/17 of my total yearly consumption.

I have about 6 KW or more of heat capability in the garage. If that gets left on when not necessary it adds up quickly.

.