In this paper, the ventilation of a “crêpe” paper-processing workshop containing dryers, which generate a high thermal load, is considered. Displacement ventilation has been used for many years in industries with high thermal load. The main ventilation design problem is to find the appropriate ventilation flow that guarantees that the interface between the fresh air zone and the hot air zone is located above the occupied region of the room. The paper presents a mathematical model, implemented in a general computer code that can provide detailed information on the velocity, temperature and moisture fields in three-dimensional buildings of any geometrical complexity. The simulation results could be used as a base for further analysis for ventilation design for other industrial processes producing high levels of thermal loads and moisture, intending to a proper ventilation system selection for a more healthy and comfort environment in a building.