Energetic and exergetic analysis of a triple-effect distiller driven by solar energy

This paper relates to the energetic and exergetic analysis of single-, double- and triple-effect distiller driven by solar energy. Energetic analysis makes it possible to define an applicable zone of operation according to the following criteria: water rejection limit to 50%, maximum salinity limit to 5.5%, and minimum energy consumption. This analysis also makes it possible to quantify energies: energy necessary for the vapour condensation and the power consumption per unit mass of pure water. Exergetic analysis makes it possible to show that the most significant exergy losses are condenser losses and water alimentation losses and that the condenser losses decrease with the number of effects. The exergetic efficiencies have also been found. They are located between 19 and 26% for a triple-effect system, between 17 and 20% for a double-effect system, and less than 4% for the single-effect system. Consequently, it seems interesting to implement a double- or triple-effect system.

This work presents energetic and exergetic analysis of single-, double- and triple-effect distiller driven by solar energy. Energy analysis made it possible to define for each system an applicable zone of operation according to the following criteria: limit the brine rejection to 50%, limit maximum salinity to 5.5%, minimize energies. This analysis also made it possible to quantify energy necessary for the vapor condensation and the power consumption per unit mass of pure water. Exergetic analysis made it possible to show that the most significant exergetic losses are the condenser losses and the incoming salted water losses and that the condenser losses fall with the number of effects. The exergetic efficiencies have also been found. They are located between 19% and 26% for the triple-effect system, between 17% and 20% for the doubleeffect system, and less than 4% for the singleeffect system. These results show that: C energies brought into play in the single-effect system are very significant C the profit is important for the double-effect system and less important for the triple-effect system. This means that, in spite of its simple design, the single-effect system generates a high operating cost. This led us to eliminate the single-effect system and to be only interested in the double- or triple-effect systems. In addition, the regulation of the flow rate of the input water was considered, which would limit, a priori, the losses of energy as well as the brackish discharges [13].