Characterization of Solar CellsCharacterization 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 2007Energy June 2007

Solar CellSolar 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 CellsTypes 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

ProjectProject Created Test and

demonstration kit– Resistive load box– Volt, current, solar

flux, and temperature meter

– Cooling system

Solar Panel– Daily measurements

Theoretical Solar FluxTheoretical Solar Flux

Potential power as measured straight above

Watts/m^2

I-V curveI-V curve

Current vs voltage Varying resistance Use resistance to determine

voltage and current for specific purpose – Voltage=Current*Resistance

Our Solar FluxOur Solar Flux

June 5, 2007

0

200

400

600

800

1000

1200

8:00AM

9:00AM

10:00AM

11:00AM

12:00PM

1:00PM

2:00PM

3:00PM

4:00PMtime

wat

ts/m̂

2̂2

above

at the sun

away from sun

Our IV curve without Cooling Our IV curve without Cooling SystemSystem

IV curveR2 = 0.9821

0

0.5

1

1.5

2

2.5

3

3.5

4

0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45

voltage

curr

entt

What affects our readingsWhat affects our readings

Clouds– Scattering – Decreasing photon absorption

HeatAngle of Solar Panel

IV Curve with Cooling SystemIV Curve with Cooling System

IV curve

R2 = 0.973

00.5

11.5

22.5

33.5

44.5

0.1 0.2 0.3 0.4 0.5

voltage

Curr

ent

ResultsResults

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

Power Voltage Curren t

Pow erPow er

Pow erw ith coo ler

w ithou t coo ler

_

_

ConclusionConclusion 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

AcknowledgmentsAcknowledgments 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 -

9876783.

Reference Reference

“Photovoltaics: Solar Electricity and Solar Cells in Theory and Practice”. Solarserver. 2007June 24. <http://www.solarserver.de/wissen/photovoltaik-e.html>

“Photovoltaic electricity”. Polar Power. 2007June 24 <http://www.polarpowerinc.com/info/operation20/operation23.htm>

“Solar”. US Department of Energy, 2007 June 24. <http://www.energy.gov/>

“Generation and Consumption of Fuels for Electricity Generation”. Energy Information Administration. 2007 March. 2007 June 24 http://www.eia.doe.gov/

http://www.pv.unsw.edu.au/images/future-students/solar-cell_p-n.jpg