Nice, but you still have zigzag pattern which is not optimal for compressor, it’s hunting. But I’ve came around this so you can maybe inspire even more.
FRC you need of course but alpha-omega is to not limit your flow temp. Not sure if you can achieve it with UFH (sorry forgot if you have radiators or floor heating), depends on the pump frequencies at given outside level, desired indoor temp and your heat looses. If on this chart of yours you are alredy at minimum compressor speed then you can’t do it but also means your system is very oversized. Seems you still running too high with compressor speed. For 35C water 1500W is pretty much. I think you can go lower. Think about it.
What I’ve done is to limit FRC to minimum up to -1C outside. From 2C outside above I use thermostat to control indoor temp since even at minimum compressor speed 22Hz the heat looses are lower for my target indoor temp so I cut out at 23.5C indoor… Then I have FRC zones that from -1 to -6C I’m using 27Hz, -6C to -11C 32Hz and so on you got the point. Thermostat is not used because heat loses are always slightly higher for target 23.5C. I have only emergency stop at 24C in case there is lot of sunshine for example and house overheats. This way it is heating as much as it can at given outside temperature so no hunting ever. I also lowering FRC if I’m coming close to target and I’m not at minimum FRC already.
Simply I did my own PID regulation and completely bypassed Samsung stupid and aggressive logic. For the moment it works very well, need to test with freezing temperatures and also above +5C. But Still if there is above +5C I hold min compressor speed which helps with dramatic water heating and then panicking like crazy. Maybe it can help you even more.
With DHW I didn’t notice any signific COP increase between 30Hz (min FRC) and 45Hz (100%). So I’ve set 356 for FRC when heating water.
This my chart from last day. You can see that max. flow temp at 1C outside is around 41C.
I have contacted samsung about it, no help, they say just look at the avg for COP. There is no control over the algorithm for it, they won’t share it eather, (If anyone has any more luck)
Not sure what you mean, its 1500W input for 7000W heating, I can’t go lower otherwise the house loses temp.
I have worked out the heat loss to be roughly 14.5kW at -2.5.
I can only limit my compressor to 40Hz with FC 50%. Wise there was a way to go less as the compressor can go down to 18-20Hz.
You can see the pump is still hunting to hold the target. Hunting is usually by oscillating at 7Hz up and down which is tragic control. With FRC you can go 10% lower with compressor speed and keep it like that it will slowly go up to max. possible output because pump is much more stable at current outdoor temperature. You need to set your weather curve flat and much higher above target… Just forget on Samsung’s two points weather curve it’s bullshit. This will eliminate hunting and you will see what max output temp you can get at that speed and outside conditions. You need to play with it and find your best compressor speed with outside temperature and desired flow temp. Of course there will be some temp fluctuation but for me it’s max. 5C and I always can add some offset to FRC when I see the power input is low. But this way you can eliminate this zigzag completely creating your own
What model do you have exactly ? That’s not possible you can go down only to 40Hz. Are you sure FRC works properly ? Of course this method will work only if you go lower at 22Hz, i know some pumps can go even lower like 14hz. But 40Hz sounds just too much and wonder why you can’t go lover ? If 40Hz is 50% then what is 100% and 150% for your pump ?
I see, then I’m afraid there is no way to prevent it. You could only write a hunting detection algorithm and turn off the pump for some minutes but not sure it’s worth of it. I don’t know how bad are these 7Hz oscillations every minute for a compressor. It’s unpleasant only if you stay next to the unit so from this point not a big deal but I’m more worried about lifespan because it’s not only about compressor frequency - with each such a big frequency change other components are stressed as well, pressures must establish etc. and if the pump fluctuates every minute… I don’t know.
