A heavy-duty vehicle (1) comprises an ORC system for waste heat recovery out of flue gas exhausted by the vehicle's combustion engine. The ORC system comprises a condenser (3) which is arranged in the slipstream of the vehicle's base structure (7). The overall width W of the condenser is in the range between 1.0 m and 3.0 m, the overall height H of the condenser is in the range between 1.0 m and 4.0 m, while the overall depth D of the condenser is in the range between 0.05W and 0.30W and in the range between 0.05H and 0.30H. Air-intake and air- outlet openings of the condenser are configured for realizing buoyancy flow of environmental air through the condenser. Thanks to the condenser's location, dimensions and configuration considerable improvements in energy savings are obtained as compared to previously proposed ORC systems for heavy-duty vehicles.