Solar Water Pumping

Why solar pumps?

Most of the energy produced in the world is used for running various kinds of pumps. Also most of the irrigation projects require a power driven pump. But the present electricity crisis is a major hindrance in using power driven pump. The solar pumps will give us independence from grid. These pumps are of good quality and highly reliable. They are easy to install, require low maintenance. These pumps are environment friendly, free from noise and pollution. Solar pumps are suitable for low yield bore wells.

Working Principle

A solar water pumping system is essentially and electrically driven pumping system by solar energy, at this instance electricity is produced by sunlight energizing photovoltaic (Solar) modules. The typical solar cell is a thin wafer of silicon that transforms light energy into electrical energy. The cells are encapsulated in flat modules to protect them from weather. Number of modules can be connected together to form array.

The array is sized to meet pumping system power requirement. To run the induction motor which is present in the pump at rated speed we have to supply rated AC power at the rated frequency. Due to the varying irradiance during the day, rated power cannot be supplied throughout the day and it might be available for a limited period during the day. Speed of the induction motor proportionate on the frequency of the AC supply, to operate the motor at lower power we apply variable frequency drive solution where frequency of AC supply is adjusted depending on the available solar irradiance, we also use advanced MPPT to monitor the array performance for the maximum available power. Consequently the motor can run at lower speeds when less power is available and at higher speeds when more power is available.VFD is the most reliable and efficient solution to run AC Motors.

Types of Solar Pumps

SPV water pumping system uses the SPV array mounted on a stand and includes one of the following motor pump sets compatible with the PV array.

  • DC surface pump ( centrifugal ) or floating pump set
  • AC surface or submersible pump set

Centrifugal pumps are suitable for areas where water is available at shallow depths such as open wells / stream / ponds / canals etc. They are driven by a DC motor. The total head is 14 m and maximum suction head is 7m. Better performance in the form of higher water output can be achieved when the suction head is kept at the minimum.

Submersible pumps are recommended where water table is available at higher depth (more than14 m) It is highly efficient and rugged multistage pump. Pumps can be conveniently placed under water so as to lift water from up to 50 m depth.