Very interesting, Trystan. I’ve been playing with this all week and it seems to match my system quite well.
I calculate I have a total radiator output of 16,655 W, and the app gives me figures around there.
Some of my radiators have fans fitted to them, and I estimate they increase output by 25% on those radiators, taking the total output to 18,000 W.
This morning started with 2 of the radiator fans not running (17,000W), and switched on at 6am. You can maybe see the effect they had on this heating cycle, as the flow temperatures drop in the second half when the fans turn on.
In the flat bit before 6am, 16.8 kW @ DT50. After the fans turn on the reported size is 18 kW.
The indoor temp I’m been using is pretty coarse though; I have an alternate feed I might try that gives average house temp, see if that give better numbers.
The estimated volume seems to be about 130 litres. I have no idea if that’s right.