Post on 16-Jun-2018
transcript
John Bowers
bowers@iee.ucsb.edu
iee.ucsb.edu
IEE Activities
New Materials for Thermoelectrics for
Refrigeration, Power Generation
and Waste Heat Recovery
Institute for Energy Efficiency
Innovating Global Energy Solutions
UC Santa Barbara
• Dynamics of Energy Efficiency (Buildings)
• Computing and
Networks
• Production and Storage
• Lighting and Displays
• Policy and
Economics
• Mark Manydosa, Minister of Tanzania, spoke of the need for improved
efficiency in irrigation systems.
• 400,000 hectares of irrigation needed for self sufficiency.
• Unaccounted usage was 50% in 2000, now 30%.
• The need for more efficient irrigation systems requires
– Sensors to determine hydration of soil
– Sensors to determine wafer flow, availability, and losses
– Actuators to adjust flows
– Ad hoc network between sensors, actuators and a global control and
monitoring center
– An autonomous decision making system
• Mark Manydosa, Minister of Tanzania spoke of the need for improved
efficiency in irrigation systems.
• The need for more efficient irrigation systems requires
– Sensors to determine hydration of soil
– Sensors to determine wafer flow, availability, and losses
– Actuators to adjust flows
– Ad hoc network between sensors, actuators and a global control and
monitoring center
– An autonomous decision making system
• This is similar to the requirements of more efficient buildings where one
wants to control lights or airflow.
• Where does cooled air flow, or how much and when. Sensors, actuators
and communication.
• One can build a network of solar powered sensors and actuators that
wirelessly communicate with each other and with a centralized controller,
with an intelligent program for optimization and control.
• Mark Manydosa, Minister of Tanzania spoke of the need for improved
efficiency in irrigation systems.
• The need for more efficient irrigation systems requires
– Sensors to determine hydration of soil
– Sensors to determine wafer flow, availability, and losses
– Actuators to adjust flows
– Ad hoc network between sensors, actuators and a global control and
monitoring center
– An autonomous decision making system
• This is similar to the requirements of more efficient buildings where one
wants to control lights or airflow.
• Where does cooled air flow, or how much and when. Sensors, actuators
and communication.
One can build a network of solar powered sensors and actuators that
wirelessly communicate with each other and with a centralized
controller, with an intelligent program for optimization and control.
• Dynamics of Energy
Efficiency
• Computing and
Networks
• Production and Storage
• Lighting and Displays
• Policy and
Economics
• A common problem in
developing countries is
burning kerosene for
lighting.
• This is expensive, polluting,
and hazardous to the user’s
health.
• A number of organizations
are addressing this need:
LUTW, BOGO,…
Dave Irvine-Halliday, founder of Light
Up The World, with two kerosene wick
lamps, previously the main source of
illumination in the village
• IEE is partnering with Engineers without
Borders, and Pangea to get low cost, high
quality solar powered lighting to people in
Ghana.
• Combines:
– Efficient, low cost, long lifetime LEDs
– Efficient, low cost, long lifetime batteries
– Efficient, low cost, long lifetime solar cells
• Efficient lighting for <$10. Pays for itself in 2 months.
• Dynamics of Energy
Efficiency
• Computing and
Networks
• Production and Storage
• Lighting and Displays
• Policy and
Economics
• Eliminate conventional refrigerators
• Eliminate need for refrigerants (CFCs and replacement gasses)
• Reduce energy consumption.
• Improve efficiency in solid state refrigerators.
. • A solid state thermoelectric refrigerator
could be 10 times smaller than a
conventional refrigerator.
• Longer Lifetime
• A typical refrigerator is replaced every 15 years.
• Solid state refrigerators should last 50 years.
Automotive ApplicationsHeating, cooling, waste heat recovery,
replace generator, replace internal
combustion engine (ZT>4 required).
Impact: Thermoelectrics
Relative
Efficiency
0.1
0.4
0.3
0.2
ZT
1 2 3 4
Commercial TE’s
Typical mechanical systems
ZT is a metric related to efficiency.
ZT~1 is common today.
Increasing ZT to 4 enables efficient solid
state refrigerators, efficient air
conditioning and efficient, cost effective
waste heat recovery.
Hot and cold
electrons in
equilibrium
Hot
electron
filter
0
1
2
3
4
5
6
7
8
-1
0
1
2
3
4
5
0 2 4 6 8 10 12 14
barrie
rf
B
Fermi Energy (eV)
Conserved
Non-conserved
New Concept to Optimize TE Efficiency:New Concept to Optimize TE Efficiency:(Metal/Semiconductor Nanocomposites) (Metal/Semiconductor Nanocomposites)
Even with only modestly low lattice thermal conductivity and
electron mobility of typical metals, ZT > 5 is theoretically possible
with hot electron filters
EEEEEEEEEEEEEEEEEEEEEEEEEE
ErAs nanocrystals in InGaAlAs
Many other Lanthanide elements are possible.
Power generator module fabrication:
EEEEEEEEEEEEEEEEEEµµµµEEmEEEEµµµµE
AAAAAEEEEEEEEEEEEEEEEmEEEEAAEEEEEEEEEEEAEEEAEEEEmEAEEE
Waste Heat Recovery or Power Generation are also possible.
(Run the refrigerator in reverse: Put in heat and take out electricity)
2015 Technology Initiatives
Zero-Net Energy Buildings and Homes
Lighting - 300Lm/W LED at the cost of a regular light bulb
Solar Cells: Double the efficiency at one-tenth the cost
1000x Faster Computing/Watt
Thought Leadership Initiatives
Distinguished Fellows Program
International Conferences
IEE INITIATIVES