A mathematical simulation of the carefully selected geometrical and operational aspects of the cross-flow Maisotsenko cycle heat and mass exchanger used for indirect evaporative air cooling is investigated. A two-dimensional heat and mass transfer model is developed to perform thermal calculations of the indirect evaporative cooling process. Presented numerical model was validated against experimental data. Simulations bring out unique features of the considered heat and mass exchanger and allow finding which of the selected geometrical and operational aspects (extending the dry working air part at fixed primary part size, increasing secondary air part at cost of a primary part, operating the HMX under uneven air flow distribution) have more significant impact on its performance. Simulation was performed for two operational conditions: variable inlet temperature and variable inlet air flow rate. (C) 2014 Elsevier B.V. All rights reserved.