Perfera heating logic

[miniluma]

Hi, first of all, I really love this project! Great work.

Regarding Perfera heating logic, I have a problem with heatover. I noticed an error when setting negative values for heatover. ("must be positive").

Here is how Perfera wall mounted units work in heat mode (This is proven. I can provide more details an links, if you want):

• There is an offset of the measured room temp / inlet teamp to the real room temp. (Probably not an offset, but caused by to the construction of the Perfera units)
• The Daikin logic stops the heating process, if the delta temp between target temp and inlet/room temp >= 4K
• E.g.: Target temp of the unit is set to 20.0°C. The unit started heating. If the measured temp is 23.5 everything is fine and heating goes on. As soon as the measured temp equals 24, the unit goes off.
• Depending on the deltaT, the unit tries to provide more heat to the room. DeltaT = 2 or 2.5 is good. If it comes closer to 4, it reduces the power of the outdoor unit and after a while also the fan speed. DeltaT < 2 leads to higher liquid temperatures. This helps to heat up cold rooms, but is inefficient.

So the optimal case for a long-running system with very low power consumption, a good SCOP (aka. low liquid temps) and low or no on/off cycles is to manage the deltaT.

Your current heating logic (with heatover=switchtemp=pushtemp=0) makes set = max + reference - current which is like inlet+1. (heatover and swichtemp increase is, right?)
But heating will start already at inlet-3.5. So you are requesting a lot of heat from the system

My first proposal: Please allow negative values for heatover
My second proposal:
Adapt the logic to Perfera behavior (at least as an option)
E.g. at current < min, set the unit target temp to inlet-2.
Let the algorithm readjust this as soon as inlet changes (always set=inlet-2)
If the room temp comes close to the desired temp (e.g. desired-0.1) reduce to inlet-3 (and follow any inlet changes)

As an experiment, you could set the target temp to inlet-3.5 if the desired temp is reached and keep it until current>max.
(It depends how quick you get the inlet in S21 to avoid the deltaT=4K and how fast the indoor unit deactivates if deltaT=4K. That needs to be tested)

[revk]

Do we think there is a bug, or do I just need to make these signed variables?

[turbolooser]

In my case I think its a bug so I have raised #227
and removed it from here

[miniluma]

Let me think about it. Maybe it needs more logic...

[miniluma]

@revk Let me show you what I mean by DeltaT Management:
This the what happens, when I make setTemp=inlet-3.5

Red is the settemp, black is the inlet, and green is a homematic room thermostat.
This is a 2MXM40A. Both rooms on quite/night mode. Demand 40%.
The lower room takes the live status of home and sends temp command accordingly. (consequently home-3.5).
The upper room has no faikin yet, so it does the same on the values from the Daikin Cloud. (Works similar, but with delayed values of ~1Min).

You see pretty steady inlet temps and the room is keeping it's temperature and I also can cool it down a bit (this only works for cooler outdoor temperatures. it's 5°C this morning)
liquidtemp is at 25-26°C (which is 10K below running it with the current faikin logic and much more energy efficient).
Also, the outdoor unit has 120-180W consumption while heating or keeping 2 rooms (blue line).

So, to conclude: Your faikin logic isn't wrong, let me say that at first.
But it's also not using the full potential to control and keep the room temperature and avoid heatback mode. So overshooting to quickly heat cold rooms is good. When you nearly hit the target room temperature, you could reduce the daikin set temperature much lower (up to -3.5, the lowest I've seen with heatover=0 and switchtemp=0 was settemp==inlet)

[revk]

Are you in the UK? I have some special double sided test Faikin boards for this, and could post one.

[davea]

I've ordered a BRC073 and cables from eBay so would also be interested in a two-way Faikin if you've got one to spare!

[revk]

If in UK I can easily post, they are made for this very case, I have not done the monitoring s/w yet, but that is pretty simple to write. Just need an address.

[davea]

In the UK yep, not far up the road from you in fact. What's the best way to get my address to you?

[revk]

I knew you would ask that! GitHub does not do DMs does it and I try not to post my email? I'm on mastodon/fesiverse @[email protected]

[miniluma]

@revk When I try to build the software, I end with "ninja: error: '/home/user/ESP32-Faikin/ESP32/secure_boot_signing_key_ecdsa.pem', needed by 'signature_verification_key.bin', missing and no known rule to make it"
Do you have a proposal how I could build a test software for my changes without much effort?

[revk]

You need to make your signing key... ESP IDF has instructions for that. Or turn off code signing.

[miniluma]

When I turn it off, can I make OTA updates of my builds and is it possible to come back to your releases later on by just changing the OTA host?

[revk]

If you have code signing off your boot loader should be able to load my code via ota. Going back may need you to reflash as my code won't ota your code unsigned.

[turbolooser]

Any Insights on this new setting? :-D
What will it do?

[revk]

FFS, this is what I get for allowing a pull request, no clue. I'll check.

[miniluma]

@revk Would it be better to move to a FTXMTesting branch to avoid unwanted changes in your main? Probably, you could provide some testing builds from time to time?

[miniluma]

Any Insights on this new setting? :-D What will it do?

Nothing yet. Going to try to implement a kind of special logic for the Perfera.

[revk]

He will not be doing anything on this branch, it will be a merge later, if it makes sense. And we have a beta test process as well.

[MUN0X]

I have a FTXM as well (that will get a faiking installed soon) where I was struggling with the -4°C in the logic of my existing automation as well.
I'm willing to beta test if needed

But honestly do we need a device specific setting in the faikin main branch?
Is it not an option to make the existing logic more granular?

• allow negative offsets for the existing setpoint calculation (eg. heatover -3 in case as described by TS)
• Introduce a second setpoint calculation that looks solely at the current inlet temperature + a new offset (new offset -2 for TS)
  ==> take lowest value of both both setpoint calculations (in case of heating)

This should result in the desired behavior without adding a lot of device specific changes to the code.
Thus allowing anyone to play around with it.

[revk]

I would rather not have model specific flag (and have removed).

Yes, changing logic to allow more options, and feature specific flags, I am happy with.

[MUN0X]

Would you be willing the implement the suggestion i made?

I have a few other ideas that might be worth considering.
How would you like me tho raise them for you? start a new topic or are feature requests via the issues tab more convenient?

[revk]

Sorry, whichever, just been a bit busy. Changing to signed is easy!

[MUN0X]

Ok, I'll issue multiple suggestions in the coming days via multiple feature requests.
I hope that helps to keep them separated for discussion and follow up. (or for you to dismiss them :-) )

[miniluma]

@revk I made a first shot of FTXM Control logic.
All depending on the isFTXM setting.
If it's set to 0, this should not affect your code.
If it's set to 1, this disables a lot of logic and applies a simple heating logic.
I also added some test to Advanced.md including the limitations.

See main...miniluma:ESP32-Faikin:ftxm_testing

Do you want me to make a PR or would you build a testing version so that I can test it first?

[turbolooser]

If you are looking for testers ... 👍

[miniluma]

If you want to test it, you can clone from here and build it.
My build fails due to some include stuff :-/

[sam-m7]

I've just discovered this thread and wanted to add some information. It's possible to change the 4 degrees offset of the Perfera units using the remote. https://www.manualslib.com/manual/2160120/Daikin-Perfera-Rxm-R-Series.html?page=251#manual

[Raspdomo]

You can indeed change it on the indoor units with the remote, however I prefer to do it in Domoticz.