Solar Photo Voltaic Water  Pumping System

   Using either AC or DC pumpsets

The Solar Photo Voltaic ( SPV ) water pumping system provides a turnkey solution for water pumping requirements. It consists of 1) Solar module 2) DC surface pumpset or AC submersible pumpset with inverter.

Solar Module    -Solar module generates DC power when exposed to Direct Sunlight. Solar module converts light energy to electricity. The total energy produced in a day depends on module wattage and average light intensity (measured in insolation) on that day. A, 37 Wp PV module generates 37 watt hour per hour for 5.5 hours i.e. 37 watts * 5.5 hours = 203.5 watt hour. This power is fed to a simple DC motor coupled to a centrifugal motor which delivers 2849 liters per day with a 10 meter total dynamic head.

The power generated by the Solar module is affected if any of the following parameters are changed;

1) The maximum light energy delivered by the sun. (1000 Watts per Sq. M.)

2) The spectrum of the sunlight differs from place to place.

3) The temperature is standardized as 25 deg C. The orientation of the Solar module. (Perpendicular to the sun rays for  maximum incidence of sunlight on the solar module)

Operation of the SPV panel - The SPV panel works as long as it gets uniform sunlight over its exposed area. The SPV module is mounted on the desired tilting structure using suitable mounting structure.

PV modules generate electricity directly from incident sunlight using monocrystalline solar cells. Each PV module consists of 36 nos. of 100 mm dia solar cell, electrically connected in series using redundant interconnects. The cells are sandwiched between two layers of Ethyl Vinyl Acetate (EVA) sheets. The bottom substrate is "TEDLAR" and top superstrate is toughened glass. The terminal box is of ABS - plastic material, where the outputs are terminated.

DC Motor Pumpset    - This is a composite unit consisting of permanent magnet DC motor coupled to a centrifugal pump. A, 37 watt peak PV module generates 37 WH per hour. Thus the pump delivers 2849 liters of water from a total head of 10 meters.

AC submersible pumpset    - This unit comprises of AC squirrel cage motor & multistage centrifugal pump. The full unit is immersed in water. The squirrel cage motor is more efficient than any other motor for water pumping. It is robust and water cooled. The input power is 3-phase AC power (a special inverter is used to convert the power from the solar module to AC 3-phase power). The multistage centrifugal pump can be used both in shallow and deep wells. A, 37 watt peak PV module generates 37 WH per hour. Thus in one hour the pump delivers 2849 liters of water from a total head of 10 meters.

Inverter    - The inverter converts DC power from the solar module to AC power for the AC motor. The unit is highly efficient and features V/F control for the squirrel cage induction motor. The solar module develops power primarily based on light intensity. At 50% intensity a 37 WP solar module delivers 18.5 Wp. The AC motor receives only 50% of rated power. The inverter reduces the frequency for the reduced voltage. Hence the AC motor does not stall. The AC motor operates at 50% the rated power. The pump delivers 50% the discharge. This clearly is an advantage over the DC centrifugal pumpset. It delivers AC power at 65Hz. Hence the pump operates at a higher frequency than a pump operated at 50Hz (normal power). As a result the pump delivers more water per watt than conventional pumps.

Application

Ideal for powering pumps, to supply drinking water and irrigate fields, 'dependably' and without harming the environment.

Advantages

Economical and reliable, the system requires only simple maintenance.

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