Transcript Document

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

Poly Crystalline
– Used in calculators
– wired in series to
– Formed at one piece
produce solar panels.
– 0.5V - 0.6V
– cheaper to produce
than single crystal cell
– The efficiency of
amorphous solar panels
is not as high Poly
Crystalline Solar Cells
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
June 5, 2007
1200
watts/m^2^2
1000
above
800
at the sun
600
away from sun
400
200
0
8:00
9:00
10:00
11:00
12:00
1:00
2:00
3:00
4:00
AM
AM
AM
AM
PM
PM
PM
PM
PM
time
Our IV curve without Cooling
System
IV curve
2
R = 0.9821
4
3.5
3
currentt
2.5
2
1.5
1
0.5
0
0.1
0.15
0.2
0.25
0.3
voltage
0.35
0.4
0.45
What affects our readings

Clouds
– Scattering
– Decreasing photon absorption

Heat
 Angle of Solar Panel
IV Curve with Cooling System
IV curve
2
R = 0.973
Current
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
0.1
0.2
0.3
v oltage
0.4
0.5
Results
Power  Voltage  Current
Power 

Powerwith _ cooler
Powerwithout _ cooler
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 - 9876783.
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