Whole House Power Monitoring

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tom baker

tom baker

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Master Electrician
I saw this on 'ask this old house'.
Sense.com
Very impressive, the software is smart and figures what is running, also determines your base or always on...
 
Hmmm. I have trouble understanding how it can know what individual loads are on. It can only look at the individual current draw and possibly the frequency of use and conclude what it might be. As mentioned you can re-label if it gets it wrong. Only problem is with similar loads/usage, what then? Still, an interesting concept.

In the video it has the Sense unit sitting in the bottom of the panel (dunno about that) with an antenna that snaps in a KO. There is apparently an external holder but no mention of how to run the power and CT cables out of the panel. If it were me I would like to see the whole thing in a separate box with flex into the panel to contain the power and CT leads.

-Hal
 
I have one. More for curiosity than anything.

It seems to be able to determine the "signature" of certain loads, like it figured out my refrig, coffee maker and garage door opener.

It has not figured out a majority of the loads in the house and gives no opportunity at this point to teach it manually. I have a large electric water heater load and it hasn't figured it out and I can't tell it what it is. They are developing the product, so we'll see where it goes.

It sits on the bottom interior of my panel and the CTs (I have the PV version too) clip onto the ungrounded conductors. The antenna sticks out a ko to "see" the wifi connectivity.
 
160214-2347 EST

The TED system has claimed this capability for quite a while. It does not work. The concept is interesting, but signature identification is difficult. Consider two similar refrigerators, freezers, furnaces, etc. How do you differentiate one 100 W bulb from another? And so on.

See plot P27 at http://www.beta-a2.com/EE-photos.html . Here only a few things are operating on and off thru the night. Can you identify one load vs another? Even though I have an idea of how to do some sorting I can not do it with certainty.

You really need transducers (current sensors) on each circuit you want to monitor.

Is a whole house monitor useful? Yes, but not for identifying individual loads. Could I identify a water heat vs some other heater (oven)? Possibly, but probability not with any high reliability.

.
 
gar said:
160214-2347 EST

The TED system has claimed this capability for quite a while. It does not work. The concept is interesting, but signature identification is difficult. Consider two similar refrigerators, freezers, furnaces, etc. How do you differentiate one 100 W bulb from another? And so on.

See plot P27 at http://www.beta-a2.com/EE-photos.html . Here only a few things are operating on and off thru the night. Can you identify one load vs another? Even though I have an idea of how to do some sorting I can not do it with certainty.

You really need transducers (current sensors) on each circuit you want to monitor.

Is a whole house monitor useful? Yes, but not for identifying individual loads. Could I identify a water heat vs some other heater (oven)? Possibly, but probability not with any high reliability.

.
Click to expand...

Sounds like if they included a manual training feature you might be able to make some headway on ID'ing loads.
 
gar said:
The TED system has claimed this capability for quite a while. It does not work.
Click to expand...
What is the sampling rate for the TED system?

The Sense representative on the Ask This Old House segment said that Sense samples at 1 MHz. Here's the youtube link to the ATOH segment:

https://www.youtube.com/watch?v=HZft4qoK7Ds

Jump to the 9:00 minute mark to hear the representative say "we're actually measuring the power at a million times a second." [How do you make those youtube links that jump to a particular spot in a video?]

Cheers, Wayne
 
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