Dr. Tahir Izhar

Pakistan is situated in sunny belt and its global solar insolation falling on horizontal is between 450-650 . This range of amounts to about 1500-3000 annual sun shine hours and 1.9-2.3 MWh/m2-year. This project intends to utilize this immense potential to serve water pumping needs of Punjab Province. In this project solar system is designed to pump water at 37 m�/hour from 60 feet of head. These constraints cover water needs of many crops like wheat and above 90% areas of Punjab Province. Selection of submersible pump is made by calculating hydraulic energy demand of any crop and according to the pump curves. Three phase 4 HP motor is used for driving multistage submersible pump and is feed from PV source rated at 1.35 times of minimum input power required for motor. VFD is used for DC to AC conversion, to cope with starting current problems and provide operational stability. Due to advancement in VFDs and soft starters solar pumping has become most economical solar application. Pump keeps on pumping water throughout the day when sufficient irradiance is available and water is stored in reservoir. The benefit of this technique is we avoid electrical storage which reduces cost of system considerably. Once reservoir is filled with required amount of water, water level sensor placed in it detects this and microcontroller commands the solenoid valve of particular patch of field to open automatically, as per watering schedule, for calculated time. Watering schedule is the input to the system which governs how much water is to be provided to crop on what date. System is capable of providing information regarding water pumping and distribution to fields using GSM SIM900D through text message.