Post on 22-Dec-2015
transcript
Thermoelectric Generation by Thermoelectric Generation by Radiative Cooling of the EarthRadiative Cooling of the Earth
Adam VoreAdam VoreStella KimStella Kim
Jung Hye LeeJung Hye LeeJovani TafoyaJovani Tafoya
OverviewOverview
• Need/Purpose
• Theory
• Theoretical vs. Actual Data
• Construction
• Advantages/Disadvantages
• Commercial Viability
• Results/Conclusion
Need/PurposeNeed/Purpose
• Solar Cells need sunlight
• Electricity is needed at night
• Maximizing generated power
TheoryTheoryIntensity
0.00E+00
5.00E+06
1.00E+07
1.50E+07
2.00E+07
2.50E+07
3.00E+07
3.50E+07
0 5 10 15 20 25 30 35
Wavelength
Inte
nsi
ty
Atmospheric Window
•The Atmosphere is clear In the 8-14m range•Most of the radiation of a 300K body is in the “Atmospheric window”
Blackbody curve for a body at 300K
Governing Equation
TheoryTheory
P
•Voltage is generated by temperature difference•Power is generated by heat flow
AK
LQT
nTSV Governing Equations
TheoryTheory
Governing Equations
Generated Electric Power
0
0.01
0.02
0.03
-140 -120 -100 -80 -60 -40 -20 0 20 40
Sky Temperature (oC)
Ele
ctr
ic P
ow
er
Gen
era
ted
(w
att
s) Electric Power (watts)
•Heat Flow Governed by Boltzmann radiation law•Typical values for Thot and Tcold are•Thot =15oC (air temperature)•Tcold=-50oC (sky radiometric temperature)
TheoryTheory
15oC
-60oC
T.E. Generator
Photon path 5oC
•Net Radiation flux out•Heat flow
DataDataOutput vs sky temp and air temp
-5.00
0.00
5.00
10.00
15.00
20.00
7:55:12 PM 8:09:36 PM 8:24:00 PM 8:38:24 PM 8:52:48 PM 9:07:12 PM 9:21:36 PM
Time
Tem
p (
oC
)
0
0.5
1
1.5
2
2.5
3
Ou
tpu
t (m
V)
Sky Temperature
Air Temp
mV output
Voltage output vs sky temperature
0
0.5
1
1.5
2
2.5
3
3.5
-60 -50 -40 -30 -20 -10 0 10 20
Sky temp (oC)
DV (mV)
•Performance was better than expected
•Probably due to Thermoelectric element not covering entire area of emmitter
Measurements taken with the following equipment•1 Apogee instruments infrared thermometer for sky temp•1 Vaisala Weather station for air temp•1 Campbell Scientific CR1000 datalogger for voltage measurements
ConstructionConstruction
• Aluminum reflectors
• Copper Emmiters
• Foam Insulation
• Thermoelectric
• Epoxy
• Dry ice
• Voltage meter
AdvantagesAdvantages
ECONOMICAL/ENVIRONMENTAL
•SUSTAINABLE RESOURCES•LESS MAINTENANCE FEE•ECO-FRIENDLY
DisadvantageDisadvantage
LIMITED AREAS
•LOCATIONS•HUMIDITY•SEASON
Commercial ViabilityCommercial Viability
• A Football field could generate 50kW• For a 1MW powerplant, you’d need 20 football
fields• At a cost of $2/cm2 it would cost $66,000,000
per football field• Costs would go down with a high level of
production• Target cost of $30,000 per football field• Low maintenance costs (cleaning)
Results/ConclusionResults/Conclusion
• A football field could power a house (average daily residential use: )
• Micro thermoelectric generator can reduce the area required
Standard thermoelectric generator mini thermoelectric generator2.5 mm2 – 1.2 mm23.6 mm2 – 38.44 cm2
• High start up costs : $50,000
Solar panel : $ 11,500 wind turbine: minimum $ 2,000/kW
• Inexpensive maintenance
• Cost effective in long-term (Average monthly electricity bill: $95.66)
Pays back after 26 yrs
• Sustainable• Environmentally
friendly
Questions?Questions?
• Please direct all your questions toward Jovani