Necessary feeds for Heatpump app

Hi,

I’m slightly confused in setting up the feeds for the Heatpump app. Some I have (LG Therma V over modbus and a Shelly clamp on the circuit), but some I don’t have. I’m wondering whether some are alternatives and if missing the values are internally derived from other feeds.

Electric use in watts - I have this, but since this is point-in-time sample, surely cumulative kWh from the Shelly is more appropriate?
Cumulative electric use kWh - I have this
Heat output in watts - I don’t have this, but (correct me if I’m wrong) isn’t it derivable from flow temps and rate? If so, do I have to derive it in a separate feed somehow?
Cumulative heat output in kWh - see previous
Flow temperature - got this
Return temperature - got this
Outside temperature - got this
Room temperature - got this
Target (Room or Flow) temperature - got target room temp (close enough anyway)
Flow rate - got this
Status of Hot Water circuit - got this
Status of Central Heating circuit - and I’ve got this too

And a supplementary question - what sort of data sampling rates are appropriate? I started off testing with 10s, but that generates quite a large amount of data over eg a year. What are people using? 30s? 60s? Since I have cumulative input power, can it be sampled less frequently? I did even work out that a reasonable daily graph draws at around 40px per hour on x axis, which suggests 60s should be plenty.

Thanks
Miles

You will need both watts and kWh; the first to plot real-time power usage and the second for daily consumption. It should be possible to get both from the Shelly, no?

You can compute heat power from flow rate and temps. Formula can be found here: Basics — OpenEnergyMonitor 0.0.1 documentation

Edit the input flow temp and at the end at `- input` the return temp and `x input` flow rate and `x` appropriate conversion factor. Log to a new feed then use Power to kWh to log that to a second cumulative feed.

Default is 10s, though 60s would be sufficient for most systems. Cumulative sample rates can be lower than for power feeds.

It’s worth mentioning that Emoncms can convert Power to Energy (kWh) using the power_to_kwh input process.

In fact, it’s often best to use Emoncms input processing to convert power to kWh since often the inbuilt energy accumulator on some meters only reports energy increments on a not very granular scale e.g every 0.5kWh

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Thanks. Makes sense so far.

Thanks. The Shelly EM device appears to deliver accumulated Wh to 2 decimal places, which is nice.

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Good progress here, but in my screwing around with feeds and inputs, I now have a Heatpump App display graph with all sorts of rubbish on it - and I’ve tried deleting the feed contents but there doesn’t seem to be a way to persuade the Heatpump App to clear itself. Is there something I’m missing?

Thanks