Hi Kev, Justin, Mark and anyone else who may be interested,
I have thinking of ways in which it may be possible to speed up the weather compensation optimisation process.
In my neck of the woods, the ambient air temperature reached a blistering 16C today, and overnight it is predicted to fall to 9C.
Taking the alleged 7C change it temperature, your weather compensation should request an appropriate change in the water flow temperature from your ASHP, dependent upon your compensation curve settings. This should be reasonably easy to check.
The change in water flow temperature should correspond fairly closely with the change in ambient air temperature, but any change in indoor air temperature may lag by several hours.
If there is no appreciable change in the indoor air temperature overnight, then the slope of the weather compensation may be close to that required.
If the indoor air temperature falls by 1C overnight, then the slope of the weather compensation curve needs to be increased. If the indoor air temperature is reducing by 1C for a 7C change in ambient air temperature, then the slope needs to be increased by approximately 0.14C per degree change in ambient temperature.
If your weather compensation is set to 55C WFT @ -5C Amb., then it would need to be increased to 59C WFT @ -5C Amb.
If your weather compensation is set to 50C WFT @ 0C Amb., then it would need to be increased to 53C WFT @ 0C Amb.
Obviously, if the indoor air temperature is increasing overnight, then the reverse should be carried out.
The last thing that I did was to change the Flow Temperature settings at ~2pm on Monday 8th. I set them to 20C & 50C, as opposed to the default settings of 30C & 50C
@kev-m Yes the main controwl pannel, ther is a temperatue sensor inside the controller and can be used as the house thermostst. Set the temperature and sit back and watch it work.
Director at Heacol | Expert Heat Pump Consultant | Book a one-to-one consultation for pre- and post-installation advice, troubleshooting and system optimisation.
is the room temperature trace really the room temperature or the temp where the Mistubishi controller is. Because that's what mine shows on Melcloud. Even though I have (non Mitsubishi) wireless thermostats, they don't communicate room temp back to the Mitsubishi unit, they just call for heat.
Certainly a thought provoking article for geeks like me.
It certainly highlights Brendon's campaign to promote weather compensation is to be seriously considered by most. Where appropriate, I personally favour the combined weather compensation with refinement by internal temperature measurement, provided the system is well designed.
Update. No change in settings and house is still a pleasant 21.5C. To remind you, the weather compensation is a baseline45C flow at -3C and 20C flow at 18C. I've moved it down 2 so that makes it 43C flow at -3C and 18C flow at 18C.
Energy used 9/11/21 was 10.4kWh. You can see the ASHP has settled down to a steady cycle every 40 minutes or so. The high peaks are the DHW kicking in.
I'm not getting carried away as it's quite mild out but that's definitely a so far so good from me.
For those interested, here is a closer look at the energy used. Each cycle is remarkably consistent, with an initial peak and a smaller plateau then a drop to near zero. The data points the monitoring sends each have marker; stop, heating, hot water, etc. At the data points at the peaks, the marker says heating but at the plateaus, it's stop. I assume parts of the system are still going but others aren't? The peaks are about 1.6kW. and the plateaus 0.9kW. Any ideas?
Update. No change in settings and house is still a pleasant 21.5C. To remind you, the weather compensation is a baseline45C flow at -3C and 20C flow at 18C. I've moved it down 2 so that makes it 43C flow at -3C and 18C flow at 18C.
Energy used 9/11/21 was 10.4kWh. You can see the ASHP has settled down to a steady cycle every 40 minutes or so. The high peaks are the DHW kicking in.
I'm not getting carried away as it's quite mild out but that's definitely a so far so good from me.
For those interested, here is a closer look at the energy used. Each cycle is remarkably consistent, with an initial peak and a smaller plateau then a drop to near zero. The data points the monitoring sends each have marker; stop, heating, hot water, etc. At the data points at the peaks, the marker says heating but at the plateaus, it's stop. I assume parts of the system are still going but others aren't? Any ideas?
@kev-mWhat software are you using to collect this data and generate these charts?
Melcloud (Mitsubishi's own cloud based system) to collect the data. The phone screenshot comes direct from the Melcloud app. The others are from a csv file downloaded from Melcloud into Google sheets.
Melcloud (Mitsubishi's own cloud based system) to collect the data. The phone screenshot comes direct from the Melcloud app. The others are from a csv file downloaded from Melcloud into Google sheets.
Whenever I try to download the CSV data it totally ignores the date ranges specified and always gives me the first 3 months or data. Are you able to download individual days worth of data?
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