By simulating the airflow patterns, velocity and pressure distributions in an industrial dehumidifier wood drying kiln, it is shown that typical dehumidifier system configurations create a risk of high levels of air recirculation at the dehumidifier, with adverse implications for dryer capacity and efficiency. The simulation results also show that, for high efficiency, it is important to avoid air recirculation. An alternative air flow configuration, which could achieve this result using a single set of fans, is presented and its performance assessed.