In this paper, we report heat capacity (C-p) data for several glycol/H2O/MgCl2 systems at 303.15-353.15K, measured via differential scanning calorimetry. Diethylene glycol (DEG), triethylene glycol (TEG), tetraethylene glycol (T(4)EG), propylene glycol (PG), dipropylene glycol (DPG) and tripropylene glycol (TPG) were the different glycols we mixed with water + MgCl2 to form ternary systems consisting of a fixed amount of a glycol (40 mass%) and variable H2O/MgCl2 proportions (4-16 mass% MgCl2). An extended Redlich-Kister-type equation was used to correlate heat capacity with concentration and temperature: the average absolute deviation (AAD) of the 198 data points from the corresponding values predicted by the correlation was 0.1%. Therefore, the new set heat capacity data or the correlation, reported for the ternary system considered, can be used with high degree of accuracy in process design calculations for dehumidifying systems. (C) 2012 Elsevier B.V. All rights reserved.