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Posted by Bill - WEL0043 on Wednesday, 19 May 2010, at 2:32 p.m.,
in response to averaging, posted by Lorne

I apologize for the delay here in responding. I got pretty busy the past few days.

Here's how to create a MTD Daily Average. It's straightforward and highly accurate.

(Unless specifically noted, Accum = N, Scale = 1, Offset = 0)

Device Names:
- DayCounter (Accum = b, Scale = 0, Offset = 41.666667)
- LKBTUHTotal (Accum = B)

Expressions:
LKBTUHTotalAvg = LKBTUHTotal_M / DayCounter_M

Comments:
DayCounter_M = number of days (in decimal) so far this month
LKBTUHTotal_M = LKBTUHTotal on a MTD basis
LKBTUHTotalAvg is an example of a MTD Daily Average.

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Doing a 30 day rolling average of each day's end of day value (i.e., daily kWh consumed) is not quite as accurate, but, I have found it to be pretty close. Here's an example of doing the rolling 30-day average of each day's energy consumption (in kWh). The concept is to obtain a rolling 30-day average of instantaneous power (watts), and then convert this to a daily energy amount (kWh) on an assumed 24 hour basis.

Device Names
L1 (Accum = b, Scale = 2) (I have 100 Amp CTs)
L1copy2 (Accum = F, Scale = 0.024)
Zero (Scale = 0.0)

Expressions:
L1copy2 = L1 + Zero

Comments:
L1 = power in watts
L1copy2 = a day's worth of power, i.e. the day's total kWh, a 'guess' based on an instantaneous power level.
L1copy2_M = 30 day rolling average of all of the 'guesses,' resulting in a reasonable approximation for total daily energy (in kWh) average for past 30 days.

Hope this helps.

Best regards,

Bill

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