Yes it is possible to have two outputs and single input in a storage. You must define both outputs and the input in the PCG (primary group). If they are all NRG, that would be easy: define PCG=NRG. If one of the two outputs is also the input, it should also work well, but thus far I have never modelled such myself.
I find it strange if you have in the results only Var_Fin (input flow) and no Var_Fout (output flow). Why would the storage in that case consume the input commodity, apparently for nothing?
I find it strange if you have in the results only Var_Fin (input flow) and no Var_Fout (output flow). Why would the storage in that case consume the input commodity, apparently for nothing?