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
HIGH CONCENTRATED PHOTO VOLTAICS (HCPV) TECHNOLOGY
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 ).
- 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.
- 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.
- 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.
- Submersible pump is a Screw Pump design with 210W capacity and operated by brushless DC motor for optimum performance.
- Expected performance of 2500 Litres per Hour pumping performance @5m Water head and for typical Solar radiation similar to Bihar
- 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
- Dual axis sun tracker with built in tracker controller and Pump Controller will provide all weather protection to Control electronics.
- 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
- 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.
- 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
- Highest level of Component indigenization ( 85% ) only imported component is Triple junction solar cells
- Easily repairable by a ordinary electrician at
village level and can be easily trained to handle repair and maintenance.
- 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.
- 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.
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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
- 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 )
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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
- 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
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