A desalination system based on the humidification and dehumidification of air is studied. The evaporator unit is based on a treated cellulose paper substratum through which water flows, and which has a large area to favor evaporation. The condenser unit is a liquid gas heat exchanger, where water vapor is condensed and the enthalpy of condensation is recovered to preheat the water. The mathematical model and experimental results are presented and it is shown that they present a good agreement. Some operating conditions for better heat recovery are presented. (C) 2011 Elsevier Ltd. All rights reserved.