Mine (R2T) is offset by 0.3C, and now my performance is very close to @matt-drummer (tbc still not MID comparable in accuracy, but much closer, and behaviour/patterns from the data are still valuable even without MID compliant sensors)
This excercise came about as a result of learning R1T on our BUH models (EDLA 09/11/14/16) is not of any use.
Absolute values are less important: heat output is more related to the delta between the values the sensors report, so the sensor data matching when the pump is running fast but with no compressor running (no heat input) is key for the mass flow rate formula.
This maybe an ESPAltherma & Home Assistant polling/template out-of-sync issue - ESPAltherma every 30 or so seconds from the HP, vs the sub-second power draw values from your external CT clamp when calculating the COP, could you filter out negative values via a template before sending to OpenEnergyMonitor?
This is a long thread and I admit to not reading it all through! It seems that folks are unsure of their COP calculation accuracy and I wonder if you are aware of this from John Cantor’s website (though I guess most are using numbers from ESPAltherma rather than a CT clamp):
Note, most of these products with a Current Clamp actually measure the current. They are accurate for normal electric heaters, but there will be a considerable error when used with electric motors. e.g. heat pumps. They can be checked or calibrated by running the heat pump whilst counting pulses of your electric meter over a time period. (use a stop-watch) . Electric meters give ‘pulses/kW’. This is printed on your electricity supply meter. Your actual consumption in kW can be calculated from this.
I’ve got a Pi Zero and a pair of DS18B20 temperature sensors that I will setup to measure the flow and return in my garage. I’m interested to see how they compare to R2T - R4T.
I will also try the calibration procedure noted above
John Cantor is clearly referring to the cheap and cheerful off-the-shelf devices that do indeed measure current - and often only current and guess a preset constant voltage - and therefore are only able to calculate (at best, if the display unit is mains-powered) or guess (at worst, if everything uses batteries) apparent power, which is what @johncantor infers by “there will be a considerable error when used with electric motors.” because the power factor of the motor means real power will be significantly less.
All OEM devices, when used with the voltage monitor (emonVs or a.c. adapter) will measure real power, to within the accuracy of their calibration. This can be better than 1% if done carefully.
Old fixed speed (non inverter, non variable) heat pumps could have quite a bad power factor. This gives a false high power reading. However, inverters have a very good powerfactor, so just measuring current can be good enough for simple analysis, and sometimes you can calibrate the CT, BUT be mindful that part-load powerfactor can be worse than full-load.
I personally like the very frequent readings from a CT clamp, but accuracy is never certain. Accurate pulse-counting from a kWh meter can be used along side a CT. … one for accuracy for COP assessment, the other for good 'resolution.
I really must find time to renew a lot of my website in case things have moved on. some of it is now quite old!
Sorry to jump on this thread. I have been comparing your system with my own (11kW Daikin -Mildenhall) For the love of me I can’t see to get anywhere near your low power draw, especially for DHW cycles. Anything you can suggest that might help? Did you have a copy of your MMI settings?
The DHW cycle uses the full power of the heat pump, it’s normal for this to be 4kW or so as the Daikin 9-16kW heat pumps all use the same compressor (intended to give 16kW).
If you have the immersion heater enabled that can lead to a much lower COP for water heating, in case that’s your issue. Spikes well over 4kW are the tell-tale.
Your heating data from March suggests that your setup is running very nicely, at least in terms of stable operation at low power.
Last night my DHW performance was atrocious, I have changed the target setpoint down from 52 to 45 ( we are not massive hot water users)..I have also selected quiet mode to see if that reduces the power draw.
Booster heater now selected to restricted and immersion heater is now selected for disinfectant cycle only.
Hopefully should see things change a little in terms of power draw.
I am hoping to fine tune this beast from last CH run in March. I think there is room for improvement.
I’ve reported this in another thread, but just to make you aware; we recently had a Daikin engineer update our EDLA09as part of their campaign. Initial results suggest that this is enabling the compressor to run at a lower output. I’ve seen as low as ~700W which is ~200W lower than before.
Yes, my system is oversized and was set up to maximise COP. This meant minimum flow of 35C, maximum 40C. I do use the Madoka thermostat and this can modulate flow to lower temperature, but it inevitably drifts up.
I am not seeing running at below 800W unless the flow is 32C or less. I plan to try lower flow temperatures (under 35) this autumn.
I’m now running at the flow temperatures I always wanted to achieve, i.e. from 25C. Happy to report I’m seeing the EDLA09 pulling from 600W power, with a decent COP.
I have it still set it to “quiet” mode (it’s really very, very quiet!) and to 60% power on the circulation pump. (These were settings I used to tame it pre-update and so may not now be required.)
It’s like a different machine post-firmware change.
that is a lot better than what it was last year , even though 600 watts is still a lot for my needs (excluding start up power ) i am now on a 6 kw daikin HP
That’s excellent! I am also running ~25C at my lowest operational ambient temp, but although I’ve seen occasional 700W it’s more usually 850W as per usual. I wonder if your 60% circulation pump power is making a big difference, although it’s “only” like 180W total, so maybe not.
What are your settings for pump speed and quiet mode? I’m looking at 9-0D, maybe 4 or 8? And quiet mode - quiet, more quiet, or most quiet? And is that scheduled? Worth a try!
So what setting do you have the pump speed on - that’s field setting 9-0D? Options are 0, 1-4 90-60% pump speed, 5-8 90-60% sampling pump speed i.e. overall or only sampling. Mine is on 6 i.e. 80% speed on sampling, or about 98W for pump, given HP takes 23W in idle - curiously the flow rate is 27l/m, vs 30l/m on full speed, that’s only 10% less.
Are you using 9-0D = 4 i.e. 60% max always? That would certainly affect power consumption anyway, by maybe <100W?
Now the weather has cooled below 8C I can compare before and after the firmware change.
I’m getting stable running for 2 hours+ at around 850W with ambient 7C. Flow is modulating between 11 and 14 l/min to control the leaving water temperature. This compares with a minimum of ~1050W before.
This gives a COP increase of about 0.2, at 7C ambient (from 4.2 to 4.4). A small, but useful improvement.
Since the update I have seen an improvement in the COP but not lowering the power much. Just after the update the power did drop from 950w to 820w but today, with the temperature drop, I see it is creeping up again to 1Kw +
