This paper studies a desalination unit with humidification-dehumidification cycle. Solar energy is considered as a source of heating. For thermodynamic analysis, mass and energy balance equations have been developed for the humidifier, condenser and other cycle components. These equations are solved numerically to analyze cycle parameters and to determine the amount of fresh water production. Sensitivity analyses on the main parameters have been done using design of experiment (DoE) method to obtain optimum conditions of the plant. In addition, several contours have been presented to help a designer to find suitable conditions for such a plant. (C) 2011 Elsevier B.V. All rights reserved.