عنوان مقاله [English]
In comparing desalination systems with other energy consuming processes, it is seen that energy consumption rate in desalination is more than in the others. Solar energy is one of the best and highest grade forms of renewable energies in the world. Therefore, utilization of solar energy for setting up of desalination systems prevails too much recently. Common exergy analysis method “Stream wise” uses input and output exergy of streams for computation of exergy efficiency and irreversibility. In the present study, an exergy analysis method named “Sink&Source” is illustrated. Common exergy analysis method usually computes system efficiency more than rational value. For example, computed exergy efficiency of high capacity system from Stream wise method is 91.84% while exergy efficiency of high capacity system is obtained as 7.43% from the Sink&Source method. The inefficiency of the traditional method is also shown in the analysis of a low capacity system. For example computed exergy efficiency of low capacity desalination system from Stream wise method is 96.77% while exergy efficiency of low capacity desalination system is 19.57% for the Sink&Source method. There is a theory about reverse relation of utility fluid temperature and exergy efficiency of systems. Validation of mentioned theory is measured by Sink&Source exergy analysis method. In the following, in order to reduce energy consumption of analyzed system, a solar field is suggested for high capacity system. Due to impossible being of implementation of the mentioned solar field in Iran and low efficiency of high capacity desalination plants a new low capacity desalination plant is suggested by imposition of little changes in operating parameters of high capacity system. The presented low capacity desalination system has higher exergetic efficiency and is capable of working with non-concentrating solar collectors. Finally indicated claim is validated by obtained results and it is shown that Stream wise method loses its functionality in some conditions.