Hi together. Im monitoring daily consumption of heatpump in kWh/D IN feed and energy produced by heatpump in kWh/D OUT feed. Both values am I presenting in bargraphs. What I need is to calculate difference between these two feeds, simply to calculate daily savings in kWh/D and present it also in daily bargraph. Im able to substract kWh/D OUT - kWh/D IN by substracting second feed from first one. But I dont know, which method to use for logging this daily difference, to be later presented as a bargraph. I tried alot of various logging methods, but result of all of them is just line graph with continous line and no bargraph with daily savings. Any idea how to substract these two feeds from each other and how to log results?
Radek
Re: Feeds difference in bargraph
Hi Radek.
If you have subtracted one feed from the other and just "log to feed" so you have an accumulating amount saved, which is what I think you have, then you should be able to use the "bargraph" visualization with the default "interval" of 86400 for daily totals and change "delta" to 1 (for true).
The only shortfall of this method is you cannot specify the time for the intervals to start and finish, so for daily each "day" is 24hrs starting and ending at what ever time you run the graph.
Paul
Re: Feeds difference in bargraph
Thanks for you fast reply, Paul. The issue is, I dont know, which kind of logging to use for saving subtracted results into feed, to be later visualised in bargraph. I tried to use phpfina, phpfiwa as wel as phptimeseries. Using anyone of these log kinds goes to visualisation only as a linegraph. This new feed is not available in selection of Bargraph visualisation.
Radek
Re: Feeds difference in bargraph
Hi Radek
I'm not entirely sure of the expected outcome of subtracting one Kwh/d from another and then logging that to a feed, The way I would do it would be to subtract the OUT Kwh feed from the IN Kwh feed and log to feed as DIFF Kwh, that feed can then be logged to a DIFF Kwh/d or use the bargraph vis as above.
Using this method I can't see how there would be any difference between IN kwh, OUT kwh and DIFF Kwh aside from values and all should be visible as daily bargraphs.If this doesn't work can you post info on your feeds, input processing and output graphs.
Re: Feeds difference in bargraph
Hi Paul,
you found it. Yes, beter than substracting kWh/D OUT - kWh/D IN is to substract power OUT - power IN and then to accumulate it into DIFF kWh. I tried and it works great.Thanks.
BUT now, another interesting calculation. Besides of calculation of longterm COP (SCOP = total kWh OUT divided by kWh IN) I would like to calculated DCOP (daily COP). Im calculating now daily kWh OUT divided by daily kWh IN = DCOP. The issue is, after midnight, daily kWh values are cleared to zero value, what brings problem with dividing operation. Do you have any idea, how to calculate daily values of DCOP and to present them in bargraph?
Radek
Re: Feeds difference in bargraph
No, sorry not off-hand "divide by zero" errors will be an issue. but if I think of something I'll let you know .
Paul