Dear TRNSYS-Users,
I use TRNSYS to simulate a Solar-Ground Source Heat Pump System. Now I encounter a convergence problem.
In my system, I choose Type1b as Solar Collector. When I run the simulation, it has many warnings and then stops at a error step. It shows that some units have not converged.
After I check the output data, I find that all the pump control signals are correct in the warning steps. The only problem is the outlet flowrate of the solar collector. The inlet flowrate and pump signal are correct, but the outlet flowrate is wrong. That means when inlet is ON, outlet is OFF; or when inlet is OFF, outlet is ON. All the warning steps are caused by this problem except two steps (there are no wrong place in them, and the outlet flowrate are correct).
I also try to run with a smaller time step than one hour, but it still doesn't converge.
When I try to use the default values of the solar collector, it also doesn't converge, even stop at a early step. And I also find that the collector area has a big influence to the stopping step.
I also try to use almost all the other solar collector proformas, but they also don't converge. But when I check the output data, there is a phenomenon different from the original Type1b. In the warning steps of all the other solar types, the solar flowate is correct, but the GHE loop and radiant floor loop pump's flowate is wrong. That means the pump signal is right, but the flowate is not according to the signal. So it seems very confusing. So why is there such a problem and how can I solve it? Thank you very much!
Best regards,
Chao |