.TransiEnt.Storage.Heat.PackedBedStorage_L4.Basics.PackedBedControlVolume_L4.medium_rock .TransiEnt.Storage.Heat.PackedBedStorage_L4.Basics.PackedBedControlVolume_L4.medium_rockMedium of storage material
model medium_rock = TransiEnt.Basics.Media.Solids.Basalt;