Re: convergence problem

This process is for cooling a multi-zone building, and it is referred to one zone (repeated once for each zone with different parameters).

1. I have a dry bulb temperature T and a Humidity Ratio HR for each zone (type 56)

2. I mix a certain amount of air of the building with outside air (Type 9)

3. I cool the air mix with an Heat Exchanger (Type 55)

4. I blow the cooled air mix to the building

q The psychrometrics and the Equations are just for certain calculations of condensations.

q I set the FLOW of cool water that flows througth the Heat Exchanger (Type 55) to keep the temperature T of the building within a certain range

This seems easy and sometimes it works fine, but most of times I get errors (I’d reather say “horrors”) like THE INPUTS TO UNITS xx xx xx etc WERE NOT CONVERGED WITHIN THE SPECIFIED TOLERANCE AT TIME = xx

I don’t know how to deal with it. I tried with both solvers, with the NOCHECK statement, with the backsolving technique, but as I’m not an expert I can’t achieve the convergence.

Referred to the Heat exchanger (Type 55), If I try to control the outlet temperature of the hot side (the air I need to cool) changing the flow of the cold water (cold side inlet flow), I never get a convergence. See picture.

Could somebody please give an advice? Now that the simulation (a hudge simulation) works, would be a pity to leave it because of this error.

Thank you