The differential enthalpies of dilution of the LiBr + 1,3-propanediol + water [LiBr/HO(CH2)(3)OH mass ratio = 3.5:1] and LiBr + LiI + LiCl + LiNO3 + water (mole ratio = 5:1:1:0.5) systems were determined at the four temperatures of 293.15, 303.15, 313.15, and 323.15 K and in the absorbent concentration ranges of 24.3-65.6 and 44.4-64.5%, respectively. These two aqueous mixtures were selected as potential working fluids for an absorption heat pump to overcome crystallization and corrosion problems caused by the LiBr + water system. The measured data were correlated with a simple polynomial equation, and the deviations between the experimental and calculated values were found to be 3.8 and 2.8%, respectively.