This report describes numerical modeling of heat and mass transfer in the Maisotsenko cycle heat and mass exchanger (HMX) used for indirect evaporative cooling. For this purpose an numerical model is developed based on the modified epsilon-NTU method to perform thermal calculations of the indirect evaporative cooling process, thus quantifying overall heat exchanger performance. The proposed mathematical model was validated against experimental data available from literature. The model results showed satisfactory agreement with results from experimental measurements. Numerical simulation reveals many unique features of considered HMX, enabling an accurate prediction of its performance. The results of computer simulation showed high efficiency gains that are sensitive to various inlet conditions, and allow for estimation of optimum operating conditions, including suitable climatic zones for the proposed unit using. (C) 2014 Elsevier Ltd. All rights reserved.