Monitoring power consumption?

Discussion in 'Electrical Forum discussion & Blog' started by Nate R, Feb 4, 2008.

  1. Nate R

    Nate R New Member

    Messages:
    472
    Location:
    Milwaukee, WI
    Anyone know of a system that will monitor my home's power usage over time as well as instantaneously? I would like computer monitoring, if possible.
  2. PEW

    PEW DIY Senior Member

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    487
  3. Nate R

    Nate R New Member

    Messages:
    472
    Location:
    Milwaukee, WI
    Really looking for one with computer interface. I like that the one you posted pulls data directly from the meter. I have a digital meter that has an optical port so I know my data would be as accurate as the power company data.

    I did find another system that will datalog. http://www.powerkuff.com/index.html

    Guy doesn't have any in stock yet, they are being made in China now. While he has no formal program yet, I don't mind doing the data work as long as I can record data points. His also doesn't pull directly from the meter. I don't know how accurate that is.

    What I would love is a system that reads from the meter AND THEN has a computer program that shows realtime usage and the ability to record data over time.

    We'll see if I can find something like that.

    Recently I've just been reading my meter every few days. And I suppose I could get a point of use meter for individual appliances, like the Kill-A-Watt. But I'm hoping for a whole house monitor.

    Anyone know of anything else?
  4. PEW

    PEW DIY Senior Member

    Messages:
    487
    Ever since (and a bit before) deregulation, there have been many concepts pushed here in Delaware on saving energy. Was a bit turned off by the claims, that just by knowing what your energy use is you will save 20% on your electric bill, come now! Did notice that the letter from the city of Milford (who sells all electricity within the city) was small enough that it could not be read.
  5. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

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    How does PowerKuff work?

    Offhand, it would seem to me that it'd be pretty tuff measuring power consumption with a device that encircled all the conductors at the same time.
  6. BrianJohn

    BrianJohn DIY Senior Member

    Messages:
    151
    Location:
    VA
    While I did not look at the posted site, monitoring KWHR on a residential service requires 2-Current sensors or current transformers, there are digital meters from EMON that do KWHR and actual KW in use simultaneously.
  7. Nate R

    Nate R New Member

    Messages:
    472
    Location:
    Milwaukee, WI
  8. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

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    That looks interesting. I've got a couple of questions I've sent off to them to get answered, but it could be just what I'm looking for. I've got a Datalogger, but when you add up the cost of the additional sensors I'd need to do all this, $200 is a fair price, and it's a ready-to-go package.
  9. Nate R

    Nate R New Member

    Messages:
    472
    Location:
    Milwaukee, WI
    Out of curiosity, what questions did you ask them, if you don't mind sharing?

    FWIW: I started doing some research recently on power consumption, etc. Found that our current 12.6 CF (Small!) fridge uses about 985 KWH a year! A new fridge for $450 would bring us down to 372 KWH, and be a bit larger! IIRC, our current fridge is from 1995 or so. Didn't think things had changed that dramatically until I looked it up.

    We'll get a new more effecient one in a couple months when we start on the kitchen remodel
    Last edited: Feb 5, 2008
  10. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,734
    Location:
    Central Florida
    The 2 questions were:

    1. The MTU appears to transmit its output via the circuit breaker it's connected to, but that would present the data on one leg only of the household wiring. How then could the receiver work if it were plugged in to a receptacle on the other leg?

    2. How are major loads detected for logging in Footprints? It looks like current is only measured at the service entrance -- I don't see how specific loads are identified. I would like to look at two major loads -- AC and water heater -- for sure, and possibly others, at the same time.

    Their (prompt) answers were:

    1. In some cases it doesn't receive data consistently...but in some cases it doesn't affect it (if the secondary transformer is nearby). A solution to the opposite-phase-issue (if you plan on moving the display all the time to places all over your house) would be to put in a phase-coupler....which you can get at RadioShack.

    2. That's what Footprints does. Among other things, it is designed to recognize major loads.

    And my folllow-up was:

    1) is no problem, probably, since the transformer is on a pole in my front yard.

    I'm still puzzled about 2). How does Footprints differentiate among several "major loads"? For example, suppose I had 2 identical water heaters -- could Footprints distinguish them and report them separately? My real "major loads" right now are the water heater, HVAC, well pump, and irrigation pump. Does this imply that I couldn't elect to define and track "minor loads" using Footprints? For example, I have several outside lights triggered by motion sensors; could I log the times they were on?

    I'll continue to report back. I just got a Kill-a-Watt, or whatever it's called, and plan to monitor our garage fridge for a week or so. I'm kind of scared what the numbers might look like. Like most garage fridges, it was moved from the kitchen when we bought our new (10/97) one, whose EnergyGuide claims 762kWh/year. The garage fridge is probably 25 years old.
    Last edited: Feb 5, 2008
  11. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,734
    Location:
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    These guys are quick

    Here's their reply:

    TEDFootprints can learn the electrical 'footprint' of any electrical load greater than 1kW (rules out your outside light scenario). If you have 2 identical water heaters, it will not know the difference. The tolerance, however, is user-adjustable....if one HWH is 2% different than the other, you could possibly get Footprints to differentiate.
    It would take a little 'eduction' on Footprints' part.

    All in all, it sounds pretty clever, and judging from the website the software is constantly being tweaked.
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,269
    Location:
    New England
    A frig doesn't have to be very old to be a big energy user. Picking a new energy star rated one can save a very significant amount of energy. Those old ones can really suck it up.
  13. Nate R

    Nate R New Member

    Messages:
    472
    Location:
    Milwaukee, WI
    Does sound clever, Mikey. Thanks for posting your questions and their responses. I think the only loads over 1KW I have would be the dishwasher, and maybe the Washer/Dryer when both are running (single stacked unit)


    I think I'll go with the TED.
  14. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,734
    Location:
    Central Florida
    Great -- I love pioneers. Let me know how it goes.
  15. Bill Arden

    Bill Arden Computer Programmer

    Messages:
    584
    Location:
    MN, USA
    I still have about 50 2S meters with "power line carrier" based AMR units in them.
    The only problem is the cost of running a system designed for a power utility.

    I am going to look into that TED system since it sounds like one of the things we were looking at writing about 10 years ago.

    Of course it would be nice if I could connect my dryer and dishwasher to my off-peak electric service, but I asked the power company and they won't let me. :(
    Something to the effect that the rate is based on heating.
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