Considering the bimodal feature of the bubble size distribution in the heterogeneous regime, a recently developed model for simulating direct-contact evaporators operating in the homogeneous regime was extended to the heterogeneous bubbling regime, enabling, thereby, the simulation of a direct-contact evaporator for any bubbling regime. The proposed model includes a correction factor for isothermal gas hold-up correlations to account for heat and mass transfer effects which arise in non-isothermal bubbling. The model predictions were shown to be in good agreement with literature experimental data for the air-water system, considering four different gas superficial velocities. (C) 2004 Elsevier Ltd. All rights reserved.