In this work, a comparison between three different configurations of deflectors inserted inside the duct of an oscillating water column device (OWC), where is attached a rotating Savonius turbine in the same domain, is done. In the first configuration, the numerical model is composed only by the Savonius turbine inside the OWC duct. In the second configuration, just one deflector is inserted upstream of the turbine region. In the third case, a second deflector is inserted, together with the first one, but downstream of the turbine. For every studied model, the geometry of the hydropneumatic chamber was varied by three values of the ratio H1/L1 (the height times the length). This geometric variation was performed according to the Constructal Design methodology. The purpose of this comparison was the evaluation of the OWC pneumatic power, the power coefficient, and the Savonius turbine power. The results indicated that for all the studied configurations, the ratio H1/L1 as well as the deflectors presence inside the OWC duct had an influence in terms of the performance indicators, especially regarding the pneumatic power, where variations up to 100 W were noticed.