Stationary parabolic, cylindrical solar concentrator for electricity production consists of the absorber (with photovoltaic panels and water pipes) and parabolic, cylindrical reflector (with metal surface) and has geometrical concentration ratio up to 4. Direct solar radiation approaches the concentrator aperture at different angles and pathways. For different aperture angles and different kinds and types of metal surfaces of the reflector, the investigation of long concentrator of this type would be that of how efficiently the direct solar radiation reaches absorber to be converted to electricity.