This paper describes laboratory experiments with a hybrid solar desalination system consisting of a humidification-dehumidification unit and single stage flashing evaporation unit configured by a (Al2O3/H2O) nano-fluid solar water heater under the climatological conditions of Tanta City, Egypt. The laboratory work has been carried out in actual thermal environment in August 2013. The validation has an emphasis on the main parameters with impact on the water production capacity. These are the solar radiation, feed water mass flow rate, inlet cooling water temperature, mass flow rate of cooling water and nano-particle volume fraction. The main conclusion is that good agreement is obtained between simulated and measured variations of water production and performance ratio values for variations of these parameters. The performance ratio of SSF unit is varied between 0.32 and 1.4 and flashing ranges between 3 and 9 degrees C. The maximum productivity of the system reached 41.8 kg/day according to test and operation conditions. The solar water heater efficiency is affected by the nano-particle volume fraction. The humidifier efficiency is affected by increasing water mass flow rate more than the increasing air mass flow rate and reaches about 98%. Finally, collector's efficiencies are about 55% and 56% for solar water heater and solar air heater respectively. (C) 2014 Elsevier B.V. All rights reserved.