Thermodynamic analyses and case studies were carried out on hybridized systems designed to improve single purpose desalination (SPD) plants. The first system considered is a conventional SPD connected to a steam generator by a pressure reducing valve (PRV). In the second system, this is replaced by a mechanical vapour compression MVC/MED unit, and in the third system by a thermovapour compression TVC/MED unit. In the fourth system, a reverse osmosis (RO) unit replaced the PRV, thus using the supplied steam to produce more fresh water.
Results of the analysis emphasize the extra water produced and the overall performance ratio increase of the plant. The included case study showed that the plant performance of the SPD was significantly improved by using any of the above systems. The extra water produced amounted to 96, 84 and 46% of the initial plant production in the second, third and fourth system respectively. SYMBOLS "A B c CP Em E hr7 -osmotic pressure coefficient (<l) -water permeation constant, g/cm2 -s -bar -salt permeation constant, cm/s -specific heat of water, kJ/kg K -specific heat at constant pressure, kJ/kg K minimum energy required for water permeation through the membrane, kWh/m3 -extra energy, kW/kg -saturated water enthalpy at effects 1-7, respectively, kJ/kg OOll-9164/86/$03.50