Characterization of Solar Cells Mary Liang Center for Adaptive Optics, Akamai Internship at Hnu Photonics Mentor: Dan O’Connell Home Institution: University of Hawaii at Manoa Collaborator: Chad Sithar

Energy June 2007

Solar Cell Si Photon passes though – Due to low energy Photon gets reflected the surface Photon absorption – Heat Not enough energy to break free of atoms Heat causes other electrons to excite and release more heat – Current Break free of atoms

Types of Solar Cells Amorphous – Used in calculators – Formed at one piece – The efficiency of amorphous solar panels is not as high Poly Crystalline Solar Cells Poly Crystalline – wired in series to produce solar panels. – 0.5V - 0.6V – cheaper to produce than single crystal cell

Project Created Test and demonstration kit – Resistive load box – Volt, current, solar flux, and temperature meter – Cooling system Solar Panel – Daily measurements

Theoretical Solar Flux Potential power as measured straight above Watts/m^2

I-V curve Current vs voltage Varying resistance Use resistance to determine voltage and current for specific purpose – Voltage=Current*Resistance

Our Solar Flux

Our IV curve without Cooling System

What affects our readings Clouds – Scattering – Decreasing photon absorption Heat Angle of Solar Panel

IV Curve with Cooling System

Results A 7% increase in current A 1% increase in voltage A 8% increase in power

Conclusion Measured an IV curve Cooling system improved efficiency Future work – Tracking System to increase photon collection – Improve cooling system design – Improve solar panel system design

Acknowledgments Hnu Photonics – Dan O’Connell – Terry Born – Richard Puga CFAO Maui Community College IFA MEDB Chad Sithar This work has been supported by the National Science Foundation Science and Technology Center for Adaptive Optics, managed by the University of California at Santa Cruz under cooperative agreement No. AST

Reference “ Photovoltaics: Solar Electricity and Solar Cells in Theory and Practice”. Solarserver. 2007June 24. “Photovoltaic electricity”. Polar Power. 2007June 24 “Solar”. US Department of Energy, 2007 June 24. “Generation and Consumption of Fuels for Electricity Generation”. Energy Information Administration March June