Solid-liquid equilibrium (SLE) data for the organic binary mixtures of n-octadecane (1) + capric acid (2) (eutectic temperature T-E = 295.15 K, eutectic composition X-1E = 0.412, latent heat of melting of eutectic mixture Delta H-fus(E) = 201 J g(-1)), n-octadecane (1) + lauric acid (2) (TE = 298.25 K, X-1E = 0.704, Delta H-fus(E) = 229 J g(-1)) were measured in this study using differential scanning calorimetry (DSC). All systems show simple eutectic behavior. These advantages of the two eutectic mixtures make them suitable in solar heating and for heat load leveling applications. The experimental data were correlated using the Wilson, NRTL and UNIQUAC activity coefficient models, respectively, and satisfactory results were presented. (C) 2014 Published by Elsevier B.V.