I start to look at your question in regards the HVAC, this area is not my expertise (so no quick resp[onse)Â - but I am looking into it. What I did in the IDF I sent is to get the simulation to continue, yes if I doubled capacity and I should have done the same to the flow and others that vary hand in hand. Definitely, there is too much heat gain in the model, but it needs to investigate where this is coming from. You need request more output for plotting and inspect.
For instance, add these (or more from .rdd files)
Output:Variable,*,Zone Air System Sensible Heating Rate,timestep;
Output:Variable,*,Zone Air System Sensible Cooling Rate,timestep;
Output:Variable,*,Zone Air Heat Balance Internal Convective Heat Gain Rate,timestep;
Output:Variable,*,Zone Air Heat Balance Surface Convection Rate,timestep;
Output:Variable,*,Zone Air Heat Balance Interzone Air Transfer Rate,timestep;
Output:Variable,*,Zone Air Heat Balance Outdoor Air Transfer Rate,timestep;
Output:Variable,*,Zone Air Heat Balance System Air Transfer Rate,timestep;
Output:Variable,*,Zone Air Heat Balance System Convective Heat Gain Rate,timestep;
Output:Variable,*,Zone Air Heat Balance Air Energy Storage Rate,timestep;
Output:Variable,*,Zone Exfiltration Heat Transfer Rate,timestep;
Output:Variable,*,Zone Exfiltration Sensible Heat Transfer Rate,timestep;
Output:Variable,*,Zone Exfiltration Latent Heat Transfer Rate,timestep;
Output:Variable,*,Zone Exhaust Air Heat Transfer Rate,timestep;
Output:Variable,*,Zone Exhaust Air Sensible Heat Transfer Rate,timestep;
Output:Variable,*,Zone Exhaust Air Latent Heat Transfer Rate,timestep;
Output:Variable,*,Zone Air System Sensible Cooling Rate,timestep;
Output:Variable,*,Zone Air Heat Balance Internal Convective Heat Gain Rate,timestep;
Output:Variable,*,Zone Air Heat Balance Surface Convection Rate,timestep;
Output:Variable,*,Zone Air Heat Balance Interzone Air Transfer Rate,timestep;
Output:Variable,*,Zone Air Heat Balance Outdoor Air Transfer Rate,timestep;
Output:Variable,*,Zone Air Heat Balance System Air Transfer Rate,timestep;
Output:Variable,*,Zone Air Heat Balance System Convective Heat Gain Rate,timestep;
Output:Variable,*,Zone Air Heat Balance Air Energy Storage Rate,timestep;
Output:Variable,*,Zone Exfiltration Heat Transfer Rate,timestep;
Output:Variable,*,Zone Exfiltration Sensible Heat Transfer Rate,timestep;
Output:Variable,*,Zone Exfiltration Latent Heat Transfer Rate,timestep;
Output:Variable,*,Zone Exhaust Air Heat Transfer Rate,timestep;
Output:Variable,*,Zone Exhaust Air Sensible Heat Transfer Rate,timestep;
Output:Variable,*,Zone Exhaust Air Latent Heat Transfer Rate,timestep;
And what I see the sales floor has about 60K and backroom 30K Watts convective heat gain? I am not sure why, maybe the local weather has created this - so try it in the original US location and see whether it reduces. So roughly 114W/m^2 - and actually this makes sense since in AUS the assumption is 118W/m^2 (the quick estimate for house air conditioning), not as you said 50W/m2 - maybe this is true in GER or the original IDF file where it is the case.
So it needs too much debugging..
I will look at the curves question when I get time this week, sorry for the delay.
Best wishes,
Tilek