Description and analysis of the theoretical cycle for absorption of water vapour from air with subsequent regeneration, by heating is presented.. Properties of the desiccant (CaCl2) applied in the study are correlated in a simplified form, which can be used in computational analysis of the cycle performance. To predict the effect of ambient conditions on the operating limits of the cycle, heat and mass balance equations are developed. In addition, an expression for the efficiency of the simple cycle is introduced. Theoretical analysis shows that strong and weak solution concentration limits play a decisive role in the value of cycle efficiency. The limits of regeneration temperature and mass of strong solution per kg of produced vapour are found highly dependent on the operating concentration of the desiccant.