DESIGN OF A SOLAR-WIND HYBRID POWER SYSTEM

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DESIGN OF A SOLAR-WIND HYBRID POWER SYSTEM

• By Prad Pathirana
• Advised by Prof. Richard Wilk

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Presentation Outline

• Background
• Target Location
• Project Description
• Savonius Type Wind Turbine
• Wind Tunnel Testing
• Results
• Lessons Learned
• Bill of Materials
• Timeline
• Future Plans
• Acknowledgements and References

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Background

• Rural coastal communities in Sri Lanka lack basic
  lighting and ventilation
• Kerosene and car batteries are used for lighting
  and short term electricity sources.
• Risk of fire and health issues
• Due to the proximity to the sea and being on the
  equator, the location is ideal for solar and wind
  power generation

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bandaragama.files.wordpress.com
www.chowk.com
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Location Wind Data

• Sea breeze, land breeze patterns are present
  throughout the day
• 10-15 mph wind on average
• Day Air flows in from the sea to land
• Night Air flows in from the land to sea

www.cbs6albany.com
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Location Solar Data

• Solar irradiation on a horizontal surface is
  approximately 7 kWh/m2/day
• The terrain near the sea is flat thus no
  obstruction to sunlight
• Latitude 7 00 NLongitude 81 00 E
• A solar panel facing up would be very effective,
  and tracking systems would be unnecessary

Sri Lanka
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Project Description

• Design a system that will harness the wind and
  solar energy available on location
• Main goal is to provide basic lighting and
  ventilation
• The system will be a direct current based system
• Solar panel may have some concentrating
  capabilities to capture low angle sunlight
• LED lighting will be used
• Small DC fan to enhance ventilation
• Aim to generate 70-100W of power

www.made-in-china.com/traderoom/panamericanco...
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Design Schematic
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Savonius Type Vertical Axis Wind Turbine

• Wind direction does not affect performance
• More torque generated in comparison to other VAWT
• Simple design
• Less efficient

http//www.hobbithole.net/Portals/1/savonius_rotor
_with_measures_better_more.JPG
www.symscape.com/blog/vertical_axis_wind_turbine
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Wind Tunnel Testing
Front
Top mount
Bevel Gears
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Wind Tunnel Testing

• Measured (at different wind speeds)
• RPM
• Power
• Torque

Basic blades with variable spacing
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Results - rpm
Wind Speed Wind Speed Wind Speed Blade Speed Blade Speed
Hz m/s Re Hz RPM
1 0.70 8123 0 0
2 1.41 16247 0 0
3 2.11 24370 0 0
4 2.81 32494 0 0
5 3.52 40617 0 0
6 4.22 48759 1.26 75.6
7 5.02 58029 1.89 113.4
8 5.83 67299 2.4 144
9 6.63 76569 2.85 171
10 7.43 85839 3.37 202.2
11 8.33 96229 5.7 342
Testing was performed with no bevel gear
attachment, free spinning
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Results - power
Wind speed(m/s) Power (W)
7.43 0.02
8.33 0.02
9.23 0.08
10.13 0.12
11.03 0.27
Transients effected measurements
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Results gear efficiency and torque
Gear efficiency
Torque
  No Gears No Gears With Gears  With Gears  gear ?
  hz m/s hz m/s gear ?
To start rotating 6.2 4.52 8.8 6.48 0.70
Maintain rotation 5.5 4.01 7.8 5.59 0.71
          0.70
Wind speed Mass Torque
m/s grams N.m
7.43 90 0.0247
8.33 105 0.0288
9.23 130 0.0357
10.13 160 0.0439
11.03 190 0.0522
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Lessons learned

• Wind tunnel testing gave an idea on how stresses
  act on a typical Savonius type blade
• Rough idea of how gears effect RPMs
• Using non-dimensional factors with the results
  can predict numbers for a larger model
• Wind flow in the wind tunnel is in one direction,
  thus the multidirectional wind harnessing
  capacity of the VAWT cannot be explored
• At very high wind speeds the VAWT may become a
  safety hazard

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Bill of Materials

Wind turbine
Wind (scoops) Savonius type blades x2 30
Generator Great Lakes Electr.Corporation (Ametek 30V) 99.99
Gearbox The exact size is to be determined 100
Solar Panel
Panel (BP350J) BP Solar 50W panel2 340
Circuitry
Charge controller Silicon Solar (SKU 06-1024)2 34.95
Voltage Converter 6-14V In-11-26 Out Voltage3 39.95
Battery 12V 36Ah Deep discharge battery 64
Battery meter MINN KOTA MK-BM-1D 16.18
Wiring 16 gage (30 ft) 20
Materials
Circuit box Aluminum box (Mcmaster Carr)1 30
Angled Aluminum Metal frame 80
Electrical components Switches, lights, etc. (All electronics)4 45
TOTAL TOTAL 900.07

1. Mcmaster Carr. (www.mcmaster.com)
2. Silicon Solar (www.siliconsolar.com)
3. Jaycar Electronics (http//www.jaycar.com/)
4. All Electronics (http//allelectronics.com/)

IEF Funding 535
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Timeline (Fall 2008)

• To do
• Test different blade designs
• Test different blade spacing

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Future Plans

• Order core parts over the winter break
• Charge controller
• Generator
• Voltage converter
• Experiment on the effects of blade spacing on the
  overall performance
• Predict performance of actual VAWT using data
  collected from the wind tunnel tests
• Design actual Solar-Wind hybrid system
• Manufacture

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Acknowledgements

• Prof. Richard Wilk
• Stanley Gorksi
• Paul Tompkins

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References

• Gupta, R., R. Das, and K.K. Sharma. Experimental
  Study of a Savonius-Darrieus Wind Machine. Assam
• Sheldahl, R.E. Blackwell, B.F. Feltz, L.V.
  Wind tunnel performance data for two- and
  three-bucket Savonius rotors. Sandia Labs.,
  Albuquerque, NM. 1978
• Yunus A. Cengel and John M. Cimbala , FLUID
  MECHANICS Fundamentals and Applications