摘要:The present study describes the designing of an economically optimum PV-RO (photovoltaic reverse-osmosis) solar powered seawater desalinating unit which is capable for desalination of Persian Gulf water with the TDS of 40,000 ppm and produces potable water which complies with international standards. This unit has the capacity of producing 1424 m3 of potable water per annum. In order to run continuously, desalinating units are equipped with lead-acid batteries, but these batteries are causing some problems and are costly. In this system, instead of storing electricity in batteries, potable water is stored in storage tanks to maintain constant flow rate of potable water. In this design, the number of photovoltaic cells to provide needed energy for the RO system is determined with the assumption that it should function with a minimum reception of solar energy. Economic assessment is also carried out to draw comparison between this system and conventional systems in terms of costs.