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[TRNSYS-users] Fwd: Problem connecting EES to TRNSYS



Hello TRNSYS community!

I have a problem trying to connect an EES heat pump model to TRNSYS. The model has calculations on every component of the heat pump plus the thermodynamic state of the exhaust humid air in the evaporator (it's an air to water heat pump).

Trying to keep it simple, for now the only inputs in the model are the Dry Bulb Temperature and the Relative Humidity percentage. based on fixed parameters as, for example, the water inlet or outlet temperature and flows, between others, the model calculates the energy flows and COP. Using that, the model runs well simulating the whole year on EES using a Lookup and Parametric Tables with the dry bulb temperature and Relative Humidity Data. 

The problem comes when I try to do the same simulation calling EES from trnsys. In a simple project file with just a Type 15-6, a type 66,printers and plotters, with EXACTLY the same input data, the EES fails to converge on several timesteps. I'm trying to start with 1 hour simulation timestep before shortening it.

I've tried several things and it seems that the problem is that EES doesn't update the Guess Values when calling it from TRNSYS. So, the model has trouble to converge without a previous clue of the solution of the system of equations.

Is it a way to automatically update Guess Values from TRNSYS? I've tried using Type 66a and Type 66d.

Thanks in advance,
Javier Vega Benavente
Mechanical Engineering student, Universidad de Concepcion



Attachment: First error message.png
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Attachment: Raise of negative number.png
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Attachment: Type 66 inputs.png
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