Jerod Day
PV/TEG Power Generation
Objectives
To estimate sun lamp setting necessary to simulate solar irradiance using thermodynamic
concepts.
To understand the Seebeck effect and to determine the most efficient set up for solar power
generation in the TEG.
To determine is a 60° V-shaped arrangement of solar cell modules is more efficient than a single
flat oriented solar cell module.
Reference sections: 4.26, 12.5.
Background
Solar Irradiance
Total solar irradiance describes the radiant energy emitted by the sun over all wavelengths that
𝑊
falls each second on 1 square meter [𝑚2 ] outside the earth's atmosphere--a quantity proportional
to the "solar constant" observed earlier in this centuryi.
Seebeck Effect
The Seebeck effect, or thermoelectric effect, discovered by T.J. Seebeck in 1822 can be utilized
to convert heat differentials into electric potential. The Seebeck effect is the generation of a
temperature-dependent electromotive force (emf) at the junction of two dissimilar metals which
is demonstrated in thermoelectric power generation modules (TEG)ii. When one end of metal is
heated the thermal gradient causes the electrons to diffuse and the phonons1 to vibrate. The
vibrating phonons preferentially allow some electrons to diffuse towards one end, creating a
difference in potential.iii
1
A phonon is a fundamental quantum mechanical vibration mode of a material that is used to explain sound in
solids.
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FIG. 1 The Seebeck effect in a TEG2
Solar Cell
A solar cell is a semiconductor device used to convert light to electric current. It is a specially
constructed diode, usually made of silicon crystal. When light strikes the exposed active surface,
it knocks electrons loose from their sites in the crystal. Some of the electrons have sufficient
energy to cross the diode junction and, having done so, cannot return to positions on the other
side of the junction without passing through an external circuit. The amount of power produced
by a single solar cell is dependent on the area of collecting light and the angle at which the solar
cell is to the collecting light. When working with multiple solar cells, the light reflected from
other solar cells becomes a factor.
Fig. 2 Schematic cross-sections of conventional and V-oriented photovoltaic cells under illumination3
2
Online image. Thermoelectric Technical Reference. 20 November 2008.
<http://www.ferrotec.com/technology/thermoelectric/thermalRef01.php>
Jerod Day
Procedure
Solar Irradiance Calibration:
PASPort VoltageCurrent Sensor
H
E
F
A
G
B
PASPort Quad
Temperature Sensor
C
D
PASCO Energy
Transfer –
Thermoelectric
Circuit board (Top)
A – Peltier Current Output
B – Peltier Voltage Output
C – Peltier Device Hot Side Temperature Output
D – Peltier Device Cold Side Temperature Output
E – Current Sensor Input
F – Voltage Sensor Input
G – Temperature Sensor Inputs (1 & 2)
H – Fan Power Inputs
3
J. Li, M. Chong, Y. Heng, J. Xu, H. Liu, L. Bian, X. Chi and Y. Zhai. Fig. 1. “Technique for enhancing generation
power density of silicon photovoltaic devices”; Electronic Letters Vol 40 Issue 19 pg. 1219 – 1221; 16 September
2004.
Jerod Day
The sun lamp being used is a Newport 69911 Arc Lamp Power Supply with a Newport Universal
Arc Lamp Housing and 500W Xenon lamp.
(1 − 𝜌 − 𝜏)𝐸̇ 𝐴 = 𝑚𝑐𝑝
𝑑𝑇
+ ℎ𝐴(𝑇 − 𝑇∞ ) + 𝑊̇
𝑑𝑡
where 𝜌 is reflectivity, 𝜏 is transmissivity, 𝐸̇ is the irradiance, A is the area of one of the
aluminum blocks, m is the mass of the aluminum block, 𝑐𝑝 is the specific heat capacity of
aluminum, h is the heat transfer coefficient of aluminum, T is the temperature of the hot side of
the TEG, and 𝑊̇ is the power produced by the TEG.
For a small time period t, heat loss due to convection and the power produced by the TEG are
approximately zero. There is also zero transmissibility through the aluminum block; therefore,
(1 − 𝜌)𝐸̇ 𝐴 = 𝑚𝑐𝑝
𝑑𝑇
𝑑𝑡
FIG. 3 TEG apparatus
1. Setup apparatus as shown in Fig. 3.
2. Connect jumper to the two threaded terminals in the bottom of the PASCO Energy Transfer –
Thermoelectric Circuit board.
3. Connect A to E.
4. Connect B to F.
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Note: For a positive voltage, switch the positive and negative terminals.
5. Connect G to C and D.
Note: Remember which channel corresponds to which side of the TEG.
6. Open “Experiment Template_TEG.ds” file in DataStudio®.
7. Set the sun lamp to 160W output power.
8. Turn on the lamp and begin recording data simultaneously. Record for approx. 10 seconds.
Note: Make sure light beam is centered and mostly within the area of the TEG.
9. Repeat step 8 for 200W, 250W, 300W, and 350W sun lamp output power. Allow 5 minutes
between each run for aluminum blocks to cool.
10. Determine the necessary sun lamp output power setting necessary to simulate solar
irradiance.
Given:
m – approx. 19 g.
𝜌 – approx. 0.61
𝑐𝑝 - approx. 900 J/kg °C
A - .001292 m2
𝑊
𝐸̇ – approx. 1353 𝑚2
TEG Experiment
1. Repeat steps 1 – 6 from the Solar Irradiance Calibration.
2. Connect H to a 6V power source.
3. Set sun lamp to ideal power output found in the Solar Irradiance Calibration.
4. Run the experiment using 3 different cooling orientations; 1.) Foam insulator, heat sink and
fan. 2.) Foam insulator and heat sink 3.) No cooling.
5. Turn on the lamp and begin recording data simultaneously. Record until TEG Output Current
and TEG Output Voltage level off on the graph displayed in DataStudio® (approx. 5
minutes). Note: Make sure light beam is centered and mostly within the area of the TEG.
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6. Determine the efficiency of the TEG in each cooling orientation.
Solar Cells
Flat:
1. Attach a single solar cell module to the ring stand and make sure it is perpendicular to the
light beam.
2. Connect the PASPort Voltage-Current Sensor to the solar cell with a linear-taper
potentiometer in series with the current sensor to adjust load.
3. Open “Experiment Template_Solar.ds” file in DataStudio®.
4. With sun lamp set at ideal power output found in the Solar Irradiance Calibration, turn on
lamp and adjust the distance between the solar cell module and the lamp housing until the
light beam is approx. the same width as the solar cells.
5. Begin recording data in DataStudio®.
6. Adjust potentiometer until the maximum power output of the solar cell module is found.
7. Use multimeter to determine the ideal load for the solar cell module.
V-shaped:
1. Attach supplied 60° V-shaped solar cell module apparatus to rind stand adjusting the ring
stand until the light beam hits directly in the center at the same distance used in the flat
orientation measurement.
2. Connect the solar cell modules in series.
3. Connect the PASPort Voltage-Current Sensor to the solar cell modules with a linear-taper
potentiometer in series with the current sensor to adjust load.
4. Open “Experiment Template_Solar.ds” file in DataStudio®.
5. Turn lamp on and begin recording data in DataStudio®.
6. Adjust potentiometer until the maximum power output of the solar cell module apparatus is
found.
7. Use multimeter to determine the ideal load for the solar cell module apparatus.
Jerod Day
Pre-Test Questions
1. What is the equation for efficiency of the TEG? (Aim/Paid)
2. Is the Total Solar Irradiance value a constant?
3. Would expect that the flat and V-shaped solar cell orientations would produce the same
amount of power considering they are receiving the same area of collecting light? Why?
“NGDC/STP – Solar Irradiance Data Archived at NGDC”;
http://www.ngdc.noaa.gov/stp/SOLAR/IRRADIANCE/irrad.html; Date Accessed: 11/20/08 8:38PM
i
ii
"Seebeck effect." McGraw-Hill Concise Encyclopedia of Physics. 2002. The McGraw-Hill Companies,
Inc. 21 Nov. 2008 http://encyclopedia2.thefreedictionary.com/Seebeck+effect
S. Sethumadhavan; D. Burger; “Power a Cat Warmer using Bi2Te3 Thin-Film Thermoelectric Conversion of
Microprocessor Waste Heat”; The University of Texas at Austin;
http://www.cs.columbia.edu/~simha/cal/pubs/pdfs/cat_warmer.pdf
iii