Dear Constanze,I would not recommend reducing the convergence criteria as much as you are doing. This would make the results meaningless.
Remember that TRNSYS' solver is a numerical procedure, and you should always keep that in mind. Think of your simulation as a system of equations. The default solver uses successive substitution in order to solve the system of equations. All iterative numerical methods are based on a guess or initial values, that are used as starting point for the iterations. If your system of equations is very complex, you have to give good guess values. Sometimes, this feels like you have to give the answer so the program gives you the back the same answer.
My suggestion to debug the system is that you start by making sure that you do not get that warning message during one time step. If you get this message, it means that you should change your initial values. In the Studio, when you double click on a component, the initial values are those that appear in the tab 'input'.
Another suggestion is to try to find the information flow that is causing problems: try deleting the connection between some components, and see if your simulation converges. This will show you the variable that is causing the convergence problem.
If you still keep having problems, please feel free to send me the project files and I will try to see what may be the problem.
Best regards, Diego Constanze.Bongs@csiro.au wrote:
Hi, During simulation the following warning occurred: Message 441: The inputs to the listed units have not converged at thistimestep. The values of the last iteration will be used to proceed.As I get this message more than thirty times Trnsys sends an errormessage and stops the simulation.I already set the tolerance convergence to 0.5 (from 0.001) and tolerance integration to 0.01 (from 0.001). Can you explain to me what is happening and how I can fix it? Does this mean that the system is too complex to be solved and are the simulation results still useful? Which maximum values for tolerance convergence and tolerance integration still manage to give me reasonable results? Cheers, Constanze _______________________________________________ TRNSYS-users mailing list TRNSYS-users@engr.wisc.edu https://www.cae.wisc.edu/mailman/listinfo/trnsys-users
-- Diego A. Arias TRNSYS Coordinator Solar Energy Laboratory University of Wisconsin - Madison 1500 Engineering Drive Madison, WI 53706