Nonisothermal desorption of the aqueous salt solutions layers on the horizontal heating surface was experimentally investigated. Water solutions of NaCl, CaCl2, LiВr, LiCl were used. Surface temperature was Tw = 80 °С. After warming, the desorption rate for salt solutions continuously decreases with increasing time. Evaporation rate of distillate is constant for a long time period. There is a significant growth of the rate at the end of the evaporation, when the film thickness becomes substantially less than 1 mm. Desorber of absorption heat pump can operate without failure when there is a small local (partial) crystallization.