Blue=Flow, Black=Return. no line means power is off.
I don't have an Ecodan and am not familiar with these plots but I do wonder if the flow/return temps are the set, not actual, flow temps (which might be rather different - they certainly can be on a Midea unit, which is what I have). My reasons for wondering are (a) they are very smooth - actual flow/returns temps at least on Midea units are much more volatile, its the set temps that are more stable (or maybe they are heavily smoothed actual temps) (b) "no line means power is off" - yes, but the actual flow and return still have a temp, but it has disappeared, it more likely the set temp goes "off" when the power is off and (c) the order of the icons in the legend, as I read them in each case it appears it could mean set/actual set/actual set/actual. Nothing is ever straight forward with these things...
Having said that, if your room temps are where you want them, and the COP is OK, then it is all a bit academic, its results that matter at the end of the day.
Midea 14kW (for now...) ASHP heating both building and DHW
Have I finally hit upon the sweet spot for my system - it's only taken me 6 weeks of near incessant monitoring testing and tweaking.. lol
Isn’t it madness? I don’t recall “self commissioning” being written in to the contract when I bought this expensive piece of kit?
Still, this group has been amazing and we now know so much more…
Your system may have been commissioned, just not very well. 🙄
From my perspective I'd done a fairly significant amount of research so was already fairly familiar with the controller settings and how to run things efficiently before it was installed. As long as I got a good installation I felt I could do what was required to get to peak efficiency should I need to (and I must say my installers were excellent from beginning enquiry to end installation).
I could argue the installers did what it said on the tin; they installed and commissioned to a 50C flow temp at -3 that was in the design. If I have any 'complaint' it would be that it appears the design and commissioning had 'average efficiency' as a baseline, whereas I was looking for 'maximum efficiency'. On that note, the design tool spat out the 8.5kW unit, I queried why the 6kW was not being proposed as it was just on the calculated heat loss. They advised most customers preferred to go bigger when the calcs were on the boarder line, I said no I want to go the other way, we had a sensible conversation and agreed on the 6kW.
As the 'expert' in my own home I was happy to take things from there to improve efficiency rather than go back to the installer. I was though expecting to make a few tweaks to the weather comp curve and I'd have a system nicely ticking away in the background at minimal LWT, little or no cycling, a COP of 3-4 easily achievable. I was not expecting all the nuanced interrelationships between LWT, RWT, DT, flow rates, HP running quirks, energy consumption, energy monitoring accuracy, system water volume, balancing etc etc.
Not showing while off is an odd quirk of that melcloud report.
Thanks for the clarification points. It seems the norm, at least among the Midea app and Mecloud, to have 'odd quirks' One of the Midea ones is phantom heaters - kWhs used by heaters that don't exist. The moral of the tale for me is to be wary of these apps, unless you know for certain what they are telling you.
Midea 14kW (for now...) ASHP heating both building and DHW
I could argue the installers did what it said on the tin; they installed and commissioned to a 50C flow temp at -3 that was in the design.
gotaASHP our plumbing engineer was excellent his pipe work and layout was a work of art. But the electrical side of things was a different story. I guess the pace of growth of many young installation companies might mean you never know who gets your job and how well versed they are in the intricacies of commissioning. I also gave them a tight brief to install everything in a very, very small cupboard.
"no line means power is off" - yes, but the actual flow and return still have a temp, but it has disappeared, it more likely the set temp goes "off" when the power is off and (c) the order of the icons in the legend, as I read them in each case it appears it could mean set/actual set/actual set/actual. Nothing is ever straight forward with these things...
Having said that, if your room temps are where you want them, and the COP is OK, then it is all a bit academic, its results that matter at the end of the day.
At one level it made sense to me that the lines should disappear since they are not just temperature readings.... they also represent a snapshot of energy being generated by the HP - and at the point of turning off the HP has ceased producing measurable new energy - even though there might still be heat energy in the pipes.
and at the point of turning off the HP has ceased producing measurable new energy - even though there might still be heat energy in the pipes.
This is the problem with proxies - measuring A as an indirect measure of B. It is a very common problem in medicine, you measure A because it is easy to measure, but doesn't really mean anything of itself, hoping A will tell you something about B, which does matter, but is very hard to measure. A common example: using blood pressure (easy to measure, but of itself not that important) to assess stroke risk (matters very much, but is very hard to measure directly). It gets even worse when you try and relate population level risk to an individual's risk. What does it mean if a doctor says you have a 10% risk of having a stroke, when there is no such thing as a 10% stroke, you either have a stroke or you don't, ie it's a binary yes or no outcome.
A similar process is at work using temperature to assess energy output. Higher temps generally mean more energy in the system, but it tells you very little about the actual energy produced by the system at any one time.
I take @mjr's point about the disappearance of the temp values when the unit is 'off' (more accurately, not generating heat, the unit is still 'on') being an odd quirk, but have to say it is a very odd quirk, because the unit is indeed still on, and the pipes still have a temperature, so why go to the trouble or turning off the recording/display of those temps? After all, nurses don't stop taking and recording a patient's temperature just because they are asleep (but still 'on' ie alive).
90% (or is it 100%?) of heat pump monitoring effort ends up at the COP. To get an accurate COP, you need accurate energy in and accurate energy out. The former is easy if you have an external dedicated third party meter supplying the heat pump. Lacking an external input meter for energy in, and always for energy out, things get a lot more complicated, because we end up using proxies, or relying on the manufacturer's own black box monitoring, which is far from ideal. Who knows where the sensor is, what it actually measures, and how much does the manufacturer 'pre-process' the data before presenting it to you? No one knows... My heat pump app does claim to show energy in and energy out, but I happen to know the energy in figure is almost always wrong, by varying amounts, because I do have a dedicated external kWh meter supplying the heat pump. How much of the rest of the data reported in the app is also wrong, and by how much?
and at the point of turning off the HP has ceased producing measurable new energy - even though there might still be heat energy in the pipes.
This is the problem with proxies - measuring A as an indirect measure of B. It is a very common problem in medicine, you measure A because it is easy to measure, but doesn't really mean anything of itself, hoping A will tell you something about B, which does matter, but is very hard to measure. A common example: using blood pressure (easy to measure, but of itself not that important) to assess stroke risk (matters very much, but is very hard to measure directly). It gets even worse when you try and relate population level risk to an individual's risk. What does it mean if a doctor says you have a 10% risk of having a stroke, when there is no such thing as a 10% stroke, you either have a stroke or you don't, ie it's a binary yes or no outcome.
A similar process is at work using temperature to assess energy output. Higher temps generally mean more energy in the system, but it tells you very little about the actual energy produced by the system at any one time.
I take @mjr's point about the disappearance of the temp values when the unit is 'off' (more accurately, not generating heat, the unit is still 'on') being an odd quirk, but have to say it is a very odd quirk, because the unit is indeed still on, and the pipes still have a temperature, so why go to the trouble or turning off the recording/display of those temps? After all, nurses don't stop taking and recording a patient's temperature just because they are asleep (but still 'on' ie alive).
90% (or is it 100%?) of heat pump monitoring effort ends up at the COP. To get an accurate COP, you need accurate energy in and accurate energy out. The former is easy if you have an external dedicated third party meter supplying the heat pump. Lacking an external input meter for energy in, and always for energy out, things get a lot more complicated, because we end up using proxies, or relying on the manufacturer's own black box monitoring, which is far from ideal. Who knows where the sensor is, what it actually measures, and how much does the manufacturer 'pre-process' the data before presenting it to you? No one knows... My heat pump app does claim to show energy in and energy out, but I happen to know the energy in figure is almost always wrong, by varying amounts, because I do have a dedicated external kWh meter supplying the heat pump. How much of the rest of the data reported in the app is also wrong, and by how much?
That particular graph displays a minimum of 24 hours and is presumably designed to show a long term picture, where it may be useful to show when the ASHP is off. There is another graph available that shows flow temps an hour at a time and these are always on, even when the ASHP isn't.
Here's my Midea energy input/output, 24 hour moving (trailing) COP and the outdoor ambient temp for the period since I got the thing up and running again (it's a long story...). For those not following the other thread (link in earlier post), these plots are done in Home Assistant using the History Explorer addon. The kWh values are pulled from the database using HA Statistics, and the COP calculated using HA Templates. All the data apart from outdoor temp, which comes from the Met Office, ultimately comes over my local network from the wired controller.
As you can see, there is an 'oddity' in the kWh use at around 1600 hours on the 12th - HA has dropped some values - but once things have sorted themselves out, by around noon yesterday, the charts are at least credible. Over the last 24 hours, COP has fallen from a bit over 3 to a bit under 3, reflecting the fall in outdoor ambient temp.
Edit 12:42 14/02/2023: removed some nonsense I wrote in the last paragraph
Midea 14kW (for now...) ASHP heating both building and DHW
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