Thermo-economic analysis of solar thermal power cycles assisted MED-VC (multi effect distillation-vapor compression) desalination processes

Solar power assisted different techniques of MED-VC (multi effect distillation-vapor compression) processes is thermo-economically analyzed and evaluated. In this work, two techniques of solar power cycles are considered to power on MED-PF-TVC, MVC (multi effect distillation thermal and mechanical vapor compressions). In the first technique, the developed solar thermal power is directly transmitted from the solar collector field via boiler heat exchanger unit toward the steam ejector of the MED-PF-TVC process. In the second technique, the electrical power generated from the SORC (Solar Organic Rankine Cycle) is used to power on the vapor compressor of the MED-PF-MVC process. The comparison is implemented according to the operation of PTC (parabolic trough collector) with Toluene organic oil and Water working fluids (2nd technique). Therminol-VP1 HTO (Heat Transfer Oil) is considered across the solar field and water is considered for boiler heat exchanger (1st technique). A case study is performed according to 4545 m3/day of distillate product. As a result, reducing the value of compression ratio with increasing the evaporator’s numbers would reduce the specific power consumption, solar field area, and thermo-economic costs. Also it is clear that the operation of steam ejector would increase the gain ratio instead of increasing the evaporator’s numbers.

► Different configurations of MED-VC desalination process are compared however, Parallel feed configuration is dominant.
► Combining solar organic cycle with such configuration is required to overcome the water shortage problem.
► The combination is evaluated based on exergy and thermo-economic analysis by using SDS (solar desalination system) software package.
► Increasing number of effects is connected with decreasing the compression ratio and top steam temperature. These parameters may reduce the product cost. It is found that solar thermal technique with MED-TVC is reliable and low in costs.