.ClaRa.Components.Furnace.BaseClasses.HopperBase.HeatTransfer_Top .ClaRa.Components.Furnace.BaseClasses.HopperBase.HeatTransfer_Topmodel HeatTransfer_Top = ClaRa.Basics.ControlVolumes.Fundamentals.HeatTransport.Gas_HT.Radiation.Radiation_gas2Wall_L2;