PCUBE SOLAR WATER PUMP is to demonstrate PORTABLE,PLUG&PLAY,PEOPLE FRIENDLY solution to Bihar farmer


PCUBE SOLAR WATER PUMP can demonstrate  how we can enhance the pumping performance with the use of high efficiency  High concentrated Photovoltaic technology with Dual axis sun tracker technology over low efficiency poly or Mono crystalline silicon panel technology  currently being employed in India for  major water pumping applications . Hi efficiency solar panel technology like Concentrated photovoltaics (CPV )  with  Concentration ratio in excess of 1000X  coupled with Dual axis sun tracker technology can leverage optimum pumping performance vis-a-vis Diesel based pumps

Portability is   assured as even if we  use  2 panels ( 440W )  as  2 panels panels  can be detached from sun tracker  and  carried  on the cart and  assembled on  site  easily with the help of spanner on to  sun tracker  frame

220W HCPV  panel  only occupies a area of  1m X 0.86m  only  hence look very compact and  one panel can be stacked on to another panel while carrying with a layer pad in between

Actual  rating of  panel  will be  235W  for  India  since  panel  rating is to be provided @1000 W/m2 DNI  due to  strong sun in India.

Sytem configuration : (Model 1) (a) 220W  HCPV  Solar panel  of  Size  1m X 0.86m  and  weight  25Kg  (b) 1Sq.Mt. Frame Dual axis suntracker with built in tracker electronics and Pump MPPT controller electronics  as  one  simple PCB with astronomical algorithm  weighing 20 Kgs. (c) 210W , DC Submersible screw type pump approx  weight  7 Kg. (d) Small wooden trolley with cast iron wheels Weight 6 Kg. (e) Connection cables (f) Flexible hose (g) Pump Flange
(Model 2)(a) 220W X 2nos HCPV  Solar panel  each of  Size  1m X 0.86m  and  weight  25Kg X 2nos (b) 2 Sq.Mt. Frame Dual axis suntracker with built in tracker electronics and Pump MPPT controller electronics  as  one  simple PCB with astronomical algorithm  weighing 30 Kgs. (c) 400W , DC Submersible screw type pump approx  weight  11 Kg. (d) Small wooden trolley with cast iron wheels Weight 12 Kg. (e) Connection cables (f) Flexible hose (g) Pump Flange

Type of Irrigation :
Flood or Drip Irrigation


 One of the strategy for reducing module cost is to reduce the amount of semiconductor material needed (the cost of the silicon solar cells typically comprises more than one-half of the module cost). Many companies are thinning the silicon wafers to reduce costs incrementally; others use thin-film coatings on low-cost substrates (such as amorphous/microcrystalline silicon, cadmium telluride, or copper gallium indium diselenide on glass or other substrates).

 Concentrated Photo Voltaic (CPV) is one such effort in this direction and uses concentrating optics to focus the light onto tiny cells, the size of the cell can be as low as 4mm x 4mm. The optics may be designed for low or high concentration. Low-concentration optics (LCPV) use silicon cells & high-concentration optics (HCPV) adopt Triple Junction solar cells made of materials such as InGaP/InGaAs/Ge .    

 HCPV Technology is a sustainable technology for long term since energy required to create Triple junction solar cell material is 70 times lower than Crystalline silicon cell  and  we have to bear in mind that the purpose of climate change initiative is to reduce carbon foot print and to create such enabling technologies should not low efficient and should not consume too much energy to create raw materials to achieve this objective.                               

The efficiency of the best GaAs solar cells surpassed that of silicon solar cells, and in the 1990s GaAs solar cells took over from silicon as the cell type most commonly used for Photovoltaic arrays for satellite applications. Later, dual- and triple-junction solar cells based on GaAs with germanium and indium gallium phosphide layers were developed as the basis of a triple junction solar cell which held a record efficiency of over 32% and can operate also with light as concentrated as 2,000 suns. This kind of solar cell powers the rovers Spirit and Opportunity, which are exploring Mars surface.

Recently, Triple Junction solar cells have been reaching increasingly impressive efficiencies, inspiring new interest in the high-efficiency, high-concentration approach. The third Generation solar cell, Triple junction compound photovoltaics, enjoys its long-term development under NASA’s Space Programs. 

 Starting few years back, the Triple junction solar cells are being re-engineered for terrestrial uses on earth. Concentrating optics both primary Fresnel lens at a focal distance from the cell and Secondary optics positioned right on top of the cells are adopted to take the advantage of high efficiency. Till date 42.3% energy conversion of solar radiation has been realized with Triple junction solar cells and very recently the record efficiency is 44.7% has been achieved for four-junction solar cells in the laboratory.

 Theoritically more than 68% of solar energy can be converted to electrical energy by adding multiple Junctions on currently developed 3 or 4 junction Solar cells and having specific junction responding to particular wave length of solar radiation.

 Triple junction solar cell has intrinsic advantage of ability to convert solar energy in to electricity from all the three spectrums (Infrared, Visible & Ultraviolet) and can achieve higher energy output (CUF) in comparision to Mono/poly crystalline silicon or Amorphous Thin film technologies.

 Concentrator Photo Voltaic is one of important technology base for grid and off grid power generation and has been recognized and with relevant industry technical standards such as IEC62108 for CPV modules.                                                                                                                          

High concentration photo voltaics (HCPV)

High concentration photovoltaic’s (HCPV) systems employ concentrating optics consisting of fresnel lenses that concentrate sunlight to intensities of 300 suns or more. The solar cells require high-capacity heat sinks to prevent thermal destruction and to manage temperature related performance losses. Multijunction solar cells are currently favored over silicon as they are more efficient.

Multijunction solar cells, originally designed for non-concentrating space-based satellites, have been re-designed due to the high-current density encountered with CPV (typically 8 A/cm2 at 500 suns). Though the cost of multijunction solar cells is roughly 100 times that of comparable silicon cells, the cell cost remains a small fraction of the cost of the overall concentrating PV system, so the system economics might still favor the Multi junction cells in coming years.

Thermal management of High concentration photo voltaic cells

Thermal management of cell is very critical to enhance the lifetime of Multi junction solar cells  more than 20 years and  hence lot of research and  development has yielded  advanced  materials which can with stand 2000 suns concentration  with  passive  cooling  such  as  proper selection of  materials for module  design  and  heat sink for quick dissipation.

For large scale power generation the High Concentrated photovoltaic module design can be managed  with passive cooling even in High Direct Noraml Irradiance (DNI)  locations such as India, Africa & Middle East and hence do not require water  unlike solar thermal power generation.

 HCPV as an integrated technology with Dual axis sun tracker as a array.

 HCPV Technology mandates the use of Dual axis sun tracker and hence has an advantage over fixed solar technologies due to higher energy collection per day and enhanced power generation due to cell conversion efficiency of more than 40% and Module efficiency of 32% and above. The dual axis sun tracker is essential to keep the concentration on to the solar cell throughout the day from sunrise to sunset. The dual axis sun trackers has been designed to position the cells in synchronization with sun movement daily(Azimuth Angle) and also including seasonal variation of sun movement ( Pitch Angle ).

Advantages :
  1. 32% Solar Module efficiency coupled with Dual axis sun tracker can give best pumping performance in its class compared to Fixed  low efficiency  Mono / Poly or Thin Film solar panels.
  2. Triple junction solar cells used in HCPV  panel  can  convert  light to  electricity from all the three spectrum ( Ultravilolet , Visible , Infrared ) and  hence can achieve a cell  efficiency of  more than 39%  compared  to  Silicon cells  which can only convert Visible light in to electricity.
  3. Triple junction solar cell conversion efficiency is not influenced  by  increase  in atomspheric temperature where as  silicon solar cells efficiency drops with rise in temperature.
  4. Submersible pump is a Screw Pump design with 210W capacity and operated by brushless DC motor for optimum performance.
  5. Expected  performance of  2500 Litres per Hour pumping  performance @5m Water head  and  for typical  Solar radiation similar to Bihar
  6. Dual axis sun tracker enhance the solar energy collection per day and hence can provide 70% to 80%  more  output  compared  to  Fixed  solar systems
  7. Dual axis sun tracker with built in tracker controller and Pump Controller will provide all weather protection to Control electronics.
  8. The tracker electronics and Pump electronics is developed in India and hence cost of replacement is very marginal in case of failures  and  even less than US$10
  9. After Assembly only occupies an area of 1 Sq. Mt. (10 Sq. Ft. )  hence can be easily demonstrated  in any location and even at the point of sale.
  10. Over all  weight  of the system  50 Kg  and  mounted on a trolley  hence can be used at  multiple places  like Small pond , Open well , Tube well  &  Tank
  11. Highest level of Component indigenization ( 85% )  only  imported  component  is  Triple  junction solar cells
  12. Easily repairable by a ordinary electrician at village level  and  can  be easily  trained  to  handle  repair and maintenance.
  13. This is the only technology where Solar panel can be repairable if needed  by  replacing  with  new  Triple junction solar cells  over a  period  of life and hence can extend the  overall  life of the system  even beyond  25 years. Silicon panels are not repairable  since they are laminated hence  has to  discarded  after few years of use  if one of the cell contact breaks due to constant exposure to heat.
  14. The Submersible pump used  is a  DC  type  and  hence  can be operated  even by  36V  Tubular battery  in case of  emergency like  water logging or flooding  and   night  operation by  borrowing  batteries on rental.
  15. System Cost :  MODEL 1  ( 220W Solar & 210W Pump ) , 2500 Litres/ Hr or 2500 X 8 Hrs = 20000 litres/Day Performance @5m water head  and 16000 Litres/Day performance @10m water head
  16. Over all  cost of the system :  INR 95000 ( Less than US$1500  for  volumes  less than 100 per  month )  &  INR 60000 ( Less than US$1000 for  volumes 1000 nos  per  month )
  17. MODEL 2  ( 440W Solar & 400W Pump )  4000 Litres / Hr or 4000 X 8hrs = 32000 Litres/Day performance @5m water head 25000 litres/day performance @10m water head
  18. Over all  cost of the system :  INR 115000 ( Less than US$1900  for  volumes  less than 100 per  month )  &  INR 90000 ( Less than US$1500 for  volumes 1000 nos  per  month )

Prototype: Basic prototype developed and tested and further support from Greenpeace  we can prepare ourselves  for  commercial launch