Varying results for the same model

We are modelling a combined cycle pwer plant. When we ran GT seperatly we got the desired result for exhaust temperature, but when we connected the GT to HRSG and ST we got a different result.. My question is, how can GT results change if it is at the beginning of the model and nothing goes back to it ?

Answer 1

[Paul]

If you are using a variable step solver, including HRSG and ST can cause the outputs of GT1 and GT2 to change if HRSG and/or ST cause the solver to adjust its step size differently as compared to when they are not included. Should be a small difference, unless in the first case the solver was taking very large steps compared to the second.