Research topic includes the construction of a mathematical model to study the effectiveness of the basic design of condensation of steam plants to develop thermoelectric centers dedicated to the production of electric power and water desalination. To maintain the thermal efficiency and maintain a minimum level of contamination , has been in the current study compared the amount of savings in consuming the amount of fuel as a result of the process of co-production of electricity and desalinated water in the proposed design, compared with the amount of fuel consumed as a result of the separate electric power production and water desalination process .In order to study the effect of this has been the design and evaporative desalination unit and multi-effect unit gas turbine and the basic termodinamics properties . the efficiency measure to develop the basic design of the steam plant.