Green Building Forum - Sub metering Tue, 19 Dec 2023 05:08:43 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Sub metering http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=271994#Comment_271994 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=271994#Comment_271994 Fri, 18 Jan 2019 18:23:21 +0000 Doubting_Thomas
Since we're all electric, I'm hoping this should be fairly straightforward with a couple of in-line sub meters. What I'm less sure on is whether there's any benefit to wiring these in permanently - I'm assuming this would be a bit more accurate than a clamp on the wire?

What do people recommend as a reliable make (i.e. fit and forget, then check up on it a few months later)..?

I don't really want to run these reporting to a permanent data logger as we tend to use the computer infrequently and only have a mobile broadband router so I'm thinking something like a domestic (dumb) power meter with a very basic kWh display, perhaps with the option to reset a second counter periodically (like a car odometer).

Thanks in advance.]]> Sub metering http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=271995#Comment_271995 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=271995#Comment_271995 Fri, 18 Jan 2019 18:44:57 +0000 Victorianeco Sub metering http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272000#Comment_272000 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272000#Comment_272000 Fri, 18 Jan 2019 20:07:22 +0000 djh
A 'revenue' meter is more accurate than a clamp (i.e. a CT or current transformer) but only because they spend more on the components. Revenue meters typically contain CTs, but certified, revenue-grade ones.

So yes, if you want accuracy, use revenue components, but why do you care about that level of accuracy?

Personally, I use an emoncms system, which has the flexibility and facilities I need. I'm presently integrating data from a neigbour's weather station into it.]]> Sub metering http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272002#Comment_272002 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272002#Comment_272002 Fri, 18 Jan 2019 20:23:11 +0000 Peter_in_Hungary Sub metering http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272003#Comment_272003 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272003#Comment_272003 Fri, 18 Jan 2019 20:30:27 +0000 djh
The Raspberry pi that that is part of my emoncms does all of that every ten seconds without me having to think about it.]]> Sub metering http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272005#Comment_272005 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272005#Comment_272005 Fri, 18 Jan 2019 20:36:08 +0000 Peter_in_Hungary Posted By: djhIndeed, yes, but then you have to read them every day (or whenever) and what? Record them on paper and then get a piece of graph paper and plot a curve? Or get out a calculator and work out the average or standard deviation or gradient or whatever?
Only if you want to collect the daily data. If you are doing a comparison then weekly or monthly might do. It depends what you want.]]> Sub metering http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272007#Comment_272007 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272007#Comment_272007 Fri, 18 Jan 2019 22:00:45 +0000 DamonHD
Rgds

Damon

(Speaking as someone who has only just given up manually reading at least 6 meters per day!)]]> Sub metering http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272009#Comment_272009 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272009#Comment_272009 Fri, 18 Jan 2019 22:18:51 +0000 djh Sub metering http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272013#Comment_272013 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272013#Comment_272013 Fri, 18 Jan 2019 23:43:41 +0000 bhommels
If you can't be bothered with running photodiode wires to all these meters, I once saw a solution using a LASCAR EL-USB battery operated logger coupled to a photodiode to store the time between flashes and extract consumption that way.

Having said that, my openenergymonitor.org based CT clamp & AC transformer DIY rig is only out by about 1% compared to the consumption meter.]]> Sub metering http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272014#Comment_272014 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272014#Comment_272014 Sat, 19 Jan 2019 00:32:36 +0000 djh -1- optical pulse reader
-2- CT clamp on the meter tail (power and energy)
-3- Enphase Envoy daily total
-4- daily total by manually reading the meter

Needless to say, they're all slightly different! :(]]> Sub metering http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272015#Comment_272015 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272015#Comment_272015 Sat, 19 Jan 2019 07:47:35 +0000 Beau Sub metering http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272016#Comment_272016 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272016#Comment_272016 Sat, 19 Jan 2019 08:16:26 +0000 CWatters Sub metering http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272080#Comment_272080 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=15984&Focus=272080#Comment_272080 Mon, 21 Jan 2019 14:15:58 +0000 Doubting_Thomas
To answer a few of the points above:

Posted By: djhI'd hope your space and water heaters are pretty much all your demand.


That's partly what I want to determine, but I've been amazed by the draw of 'unregulated' use items such as AV amplifiers, cookers etc. in the past.

Posted By: djhwhy do you care about that level of accuracy?


I don't, to be honest. Just interested in what that means in practical terms. If the current flow is small enough, would the readings be useless because the margin of error on any reading would outweigh the practical data? I'm guessing not, since these instruments are commercially available, but interested nonetheless.

Posted By: CWattersused an efergy clamp on meter for awhile. Seemed reasonable accurate


From all your answers above, I think a clamp-on system sounds perfectly adequate. Thank you all.]]>