Thermoeconomic and exergy analysis in using hybrid systems (GTÂ +Â MEDÂ +Â RO) for desalination of brackish water in Persian Gulf

In this paper, a Gas Turbine + Multi Effect Desalination + Reverse Osmosis (GT + MED + RO) system is designed with respect to Siemens gas turbines, to provide water and electricity for Bashagerd County, located in the south of Iran (in the outskirts of Persian Gulf). There is 79.2 × 106 (kWh/year) and 10304.3 (m3/day) of electricity and water demand, respectively. Siemens GT model 400 (SGT400) is selected to provide electricity in the place. It is seen in MED system that there is a major difference between desalinated and required water. But, as we have high rates of flow in rejected water from MED condenser to the gulf, an RO system is used in rejected outflow of the MED system. By doing so, more fresh water is derived from the whole system. In this design, the recovery of RO system is 42 %, and final price 2.3 $ per cubic meter. By using GT + MED + RO hybrid system, not only the required electricity, but also enough fresh water can be produced for this County. The hybrid system had some added costs. And the final price is reduced from 2.8 to 2.3 $/m3 by using the excess electricity to run the RO pump.