It sounds like we are following similar paths. I don't think the lag is quite as significant in my system as yours but it is certainly measured in hours.
What I have at the moment is simple, it aims to maintain the floor water temperature at a set value but, as you rightly say, this doesn't maintain the room temperature. So far I have been manually altering the water temperature depending on the weather.
The whole idea of the enhancement I'm working on now is to use the predicted future temperature to increase or decrease the water temperature early to compensate for the lag.
As the house is occupied 24 x 7 I'm not worried about controlling daytime/weekend temperature changes although I may do something about reducing the night-time temperature a degree or two.
I've only just started recording values for outside/inside/water temperatures to plug into my equations, I think we have pretty similar figures which is encouraging, for example 9C outside, 30C water => 23C inside.
The weather feed I'm using gives 3 hourly predictions for 5 days ahead so you could use that to feed into your system.
Acuario
|