Water scarcity is becoming one of the serious global challenges due to increasing population, industrialization and contamination of existing water resources. To increase the supply of fresh water in order to meet its growing demand, desalination has been practiced worldwide from many years. In the present paper a single stage flashing (SSF) desalination system coupled with the nano-fluid based direct absorption solar collector (DASC) with the help of a counter-flow heat exchanger has been studied numerically. The thermal performance of the entire system is measured in terms of gained output ratio (GOR).The effect of various influencing parameters such as height (H) and length (L) of the collector, particle volume fraction (fv) of nanoparticles and incident flux (q) on gained output ratio (GOR) and top brine temperature (To) is studied numerically. © 2018 by the authors of the abstracts.