id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
5812	Start values lost in big power plant initialization	Francesco Casella	Karim Adbdelhak	"When trying to simulate {{{FlexiCaL.Plants.Test.TestPlantDeltaOffDesign}}} with {{{-d=evaluateAllParameters}}}, I get a solver failure at the first iteration of the big nonlinear system of equations for lambda = 0.

This is most likely due to wrong start values, since the model is successfully initialized by Dymola. Some analysis reveals that the two most probable causes are
- loss of start values for {{{fixed = false}}} parameters
- loss of start values for some enthalpy variables.

The former issue is addressed in see ticket:5807#comment:9.

The latter issue is reported here. For example, the flattened model contains
{{{
Real Plant.Carbonator.SH.htilde[10](
  quantity = ""SpecificEnergy"", unit = ""J/kg"",
  min = -10000000000.0, max = 10000000000.0,
  start = 3331000.0, nominal = 500000.0,
  stateSelect = StateSelect.prefer) ""Enthalpy state variables"";
}}}
but then the nonlinear solver diagnostic message reports
{{{
proper start-values for some of the following iteration variables might help
...
[306] Real Plant.CalcinerSection.a_SH2_1.fluidFlow.htilde[4](start=100000, nominal=500000)
...
}}}
with the start value of 100000 being the default start value for the type used to define {{{htilde}}}."	defect	new	high	Future	Backend