1. No category

Nanotechnology for Energy and
Environment
BIOE298 DP
Sustainable Energy: Need a Major
Breakthrough
A major technological challenge for human race in 21st
century is the transition from fossil-fuel-based energy
economy to renewable (sustainable) energy one.
• Collective energy demand of the planet is predicted
to be doubled by the mid of 21st century and to be
tripled by the end of this century.
• There is a urgent need to develop CO2- neutral
energy sources.
• The sustainable energy alternatives should be cost
effective.
The Importance of Nanoscale Properties
Quantum size effects (atomic level of matter) result in
unique mechanical, electronic, photonic, and magnetic
properties of nanoscale materials
• Chemical reactivity of nanoscale materials greatly
different from more macroscopic form, e.g., gold
• Vastly increased surface area per unit mass, e.g.,
upwards of 1000 m2 per gram
• New chemical formation , e.g., fullerenes, nanotubes
of carbon, titanium oxide, zinc oxide, other layered
compounds
• The melting point of gold particles decreases dramatically as the
particle size gets below 5 nm
• For nanoparticles embedded in a matrix, melting point may be
lower or higher, depending on the strength of the interaction
between the particle and matrix.
Benefits already observed from the design of
nanotechnology based products for renewable energy
are:
•An increased efficiency of lighting and heating
•Increased electrical storage capacity.
•A decrease in the amount of pollution from the use
of energy
Opportunities of Nanoparticles for Energy
and Environment
Workshop on Nanotechnologies for Thermal and Solar Energy Conversion and Storage, August 10,11, 2008,
Jacksonville, FL
Portfolio of solar/thermal/electrochemical energy conversion,
storage, and conservation technologies, and their interactions
More efficient devices for…
• LED-based lighting
• Thermoelectric refrigeration
• Thermoelectric and thermo-photovoltaic conversion of
waste heat
• Photovoltaic conversion of solar energy and production
of hydrogen
Other benefits
• Compact
• Robust
• Low environmental impact
Challenges
• Efficiency breakthroughs needed!
• Availability and price of raw materials
• Manufacturing costs
Electricity generation accounts for about 37% of
primary energy consumption in the U.S.
• Lighting accounts for 22% of the nation’s electric
power usage.
• The DoE SSL Goal: a solid-state lamp that is more
efficient, longer lasting and cost competitive compared
to conventional technologies, targeting a system
efficiency of 50% and the color quality of sunlight.
• Implications of Success: 33% reduction in energy
consumed for lighting by 2025, eliminating need for 41
1000MW power plants, and saving consumers $128 B+.
III-V LEDs cover the visible spectrum,
but not with one materials system
Compound Semiconductor, June 2008, pg. 17
Low cost solution:
Blue (In,Ga)N LED with
partially absorbing yellow
phosphor
Limitations: poor color
rendering, low efficiency
due to Stokes shift
Warm light solution:
Board-level integration of
(In,Ga)N/yellow phosphor
and (Al,Ga,In)P red LEDs
Limitations: “green gap”,
high cost of assembly
Photovoltaic Solar Cells
• Generate electricity directly from sunlight
• 2 Main types:
– Single-crystal silicon (traditional)
• Widespread
• Expensive to manufacture
Silicon-based
– Dye-sensitized (“nano”)
solar cell
• Newer, less proven
• Inexpensive to manufacture
• Flexible
Dye-sensitized
solar cell
• Problem: Fast energy loss by hot carriers
– Hot carriers are produced when solar photons with
energy significantly higher than the band gap of the
semiconductor is absorbed. Excess energy leads to
lattice vibrations and thus affects the efficiency.
• Solution 1: Use of Si nanocrystals with different
band gap values to capture the full solar spectrum
• Solution 2: Use of quantum confined nanocrystals
to generate multi-exciton generation
Organic dye sensitized solar cells
• Charge-carrier recombination problem can be
addressed by using nanoparticle /nanostructures.
• Carrier collection efficiency can be improved by
using one dimensional nanostructures such as
nanowires and nanotubes.
• Nanotechnology may provide routes for cost
reduction by using thin films.
Hydrogen from solar water splitting
• Photoreduction of CO2 with water to form hydrocarbon
(methane, methanol etc.)
– This approach is very interesting as using CO2 as a raw
material to produce hydrocarbon fuels just by using sun
light.
– Negative CO2 foot print
– Not only interesting from the environment point of view,
but also from the view of sustainable transportation using
the existing Infra structure for fuel distribution
Solar Photocatalysis
• TiO2 nanoparticles are used in solar water
splitting
• Increasing the efficiency of the process is a
main challenge
• Oxynitride of TiO2 (TiO2-xNx) is a better
alternative
• Nanosized TiO2-xNx can absorb in the
visible region
Fuel Cells
• Despite the huge advantages, their
commercialization is hampered by:
– High cost
– Durability issues
– Operability issues
• Solutions for some these bottlenecks will be from
nanotechnology
• e.g.: Replacing Pt catalysts with some cheaper
material in low temperature fuel cells
What is the problem?
Hydrogen fuel cell development has some practical issues
associated with cost benefit and infrastructure development for
safety and economics (e.g., fuel manufacturing, transportation,
and storage).
Although hydrogen has a high energy density by weight, it has a
low energy density by volume as compared to hydrocarbon-based
fuel cells. Thus, hydrogen storage is one of the bottlenecks for
hydrogen fuel cell development since high-pressure compressed
gas tanks are large and heavy. In addition, compressing hydrogen
to high pressures require energy as well, defeating some of the
cost benefits with fuel cells. Liquid hydrogen storage, which does
not have a great energy density by volume as compared to
hydrocarbon, also requires cryogenic storage – a bulky and
expensive option.
Hydrogen storage in tanks presently
used in hydrogen-powered vehicles
a) Hydrogen production and storage by renewable resource, (b) hydrogen storage in metal
doped carbon nanotubes , (c) storage in mesoporous zeolite: by controlling the ratio of
different alkali metal ions (yellow and green balls), it is possible to tailor the pressure and
temperature at which hydrogen is released from the material, (d) hydrogen storage in
metal–organic framework (MOF)-74 resembles a series of tightly packed straws comprised
mostly of carbon atoms (white balls) with columns of zinc ions (blue balls) running down
the walls. Heavy hydrogen molecules (green balls) adsorbed in MOF-74 pack into the
tubes more densely than they would in solid form.
Hydrgen gas (red) adsorbed in an array of carbon nanotubes (grey). The hydrogen inside
the nanotubes and in the interstitial channels is at a much higher density than that of
the bulk gas
The growth of large-area graphane-like film by RF plasma beam deposition in high
vacuum conditions. Reactive neutral beams of methyl radicals and atomic hydrogen
effused from the discharged zone and impinged on the Cu/Ti-coated SiO2/Si samples
placed remotely. A substrate heating temperature of 650 °C was applied
http://www.intechopen.com/books/hydrogen-storage/hydrogen-storage-for-energy-application
a) STM images of graphane. The bright protrusions in the image are identified as
atomic hydrogen clusters; (b) after annealing at 300 °C for 20 min; (c) after annealing
at 400 °C for 20 min; (d) graphene recovered from graphene after annealing to 600 °C
for 20 min. Scale bar 3 nm
Nanotech Materials for Truly
Sustainable Construction
 60% of global industrial waste is from the
construction and demolition of buildings
 60% of electrical use in developed nations is by
buildings
 40% of total energy consumed is by buildings
Old or new? (Damascus 900-1750AD)
• Arms race? The first crusaders encountered better steel
 Wootz steel, developed in India & Sri Lanka ~300 BC
 greater strength & flexibility due to carbon nanotubes
 technique lost ~1750AD
The Revolution in building science
A quick overview
Put on your running shoes…

Steel

Filtration

Concrete

Electronics / Sensors

Glass

Tools

Gypsum Drywall

Coatings & Paints

Fabrics & Carpet

Lighting

Energy/HVAC

Insulation
Steel
 Nanocomposite steel is available & stronger
(per ASTM)
 Withstands temperatures as low as -140F
 Increased plasticity
 Free of corrosion-causing carbide paths
 Results:
 reduced amount of steel
 Simplified placement of structural
concrete
 20 to 40% savings
Concrete
 Production of concrete accounts for 8%
of total CO2 emissions worldwide
 Translucent concrete?
Glass
 Can block UV & glare
 Self-cleaning glass coated (titanium dioxide coating
breaks down organic matter
Switchable Glass
Switch!!
Gypsum Drywall
 Nano-drywall is lighter, stronger and water resistant
Fabrics and Carpet
 Nano-treatments are used on commercial fabrics
 Color-fast, stain proof and dirt proof
 Naturally hydrophobic, no mold or mildew
Energy / HVAC
 Solar cells infused with nano-technology are thin,
flexible and come in rolls so they can be applied as
roofing material
Tools
 Doped Nanophostate Lithium Ion batteries
 Cordless tools are more powerful than corded!
Coatings and Paints
 Nano particles enhance physical and aesthetic
qualities
 Hard, durable finish
 Excellent water resistance
 Scrub-ability
 Stain blocking and other properties
Lighting
• LEDs (point source) & OLEDs (sheet)




40% of commercial energy goes to lighting
LED is most efficient, sustainable solution
10X more efficient than incandescent
50,000 - 100,000 hours (vs 10,000)
"No other lighting technology offers so much potential to save energy and
enhance the quality of buildings"
U.S. Dept. of Energy
Solid-state lighting
Big technology push
 46% average annual growth from 2001-2004
 HB LED market $4.2 billion in 2006
 Growing to $9.9 billion in 2011
*Examples: Osram, Philips, OptiLED Holdings (Hong Kong)
Solid-state lighting
Insulation
 Aerogel, a translucent thermalacoustic insulator
 Looks like frozen smoke
 Best insulating solid in the world
 Weighs only 90 grams per liter
 Extremely flexible
- blankets, beads, sheets
The new “plastic”*
*Not really—it’s amorphous silica
(sand)
How to use these innovations?
• Steel
• Filtration
• Concrete
• Electronics / Sensors
• Glass
• Tools
• Gypsum Drywall
• Coatings & Paints
• Fabrics & Carpet
• Lighting
• Energy/HVAC
• Insulation
Sound Transmission: Acoustic Performance
•Truck Noise
•10 db attenuation 40 - 400 HZ sound transmission
•loss 2-3/4” FRP
Fiberglass insulation
Nanogel®
Sound pressure level vs. time
About aerogels

Well-known, insulating nano-substance that is translucent
and 97% air

NanogelTM* panels – developed for skylights –

Lightweight

Hydrophobic

Highly translucent

Thin

Superb thermal / acoustic insulator

Manufactured as large, rigid panels
Heat, Light, & Noise
Thermal Performance
 R-20 The insulating value of
a 6” stud wall
Testing
Permanence of
performance
 Non-combustible/
no smoke
 Mold/mildew resistance
 Condensation resistance
 UV Stable
Noise
 50% Sound
Reduction
More about Aerogels

Nanomaterial known since 1931

Used extensively in aerospace

NanogelTM is a proprietary form of “aerogel”
- skylights
- exterior glazing
- pipeline insulation
- apparel
- medical devices
More about Aerogels

Nanogel used across North America & nine
European countries

Not an experiment!

Cabot is 125 years old, a $2.9 billion public
company
- 21 countries
- 36 manufacturing sites
- 8 R&D facilities
Examples – Skylights
Applications
•
Application : a 25mm thick multi-wall polycarbonate
sheets façade filled with nano-material
•
(Total surface of 1450m2) on the whole perimeter of
the building (surface of 3360m2).
•
The façade had to meet a thermal insulation value <
2.7 W/m.K
•
The nano-material allows to achieve a value of 0.89
W/m.K
Options
Shaders
•
Shaders were not an option : very costly, heavy
structure, not in line with the architect’s concept of a
smooth building surface
Cost comparison
Nano-Materials
(aerogels) applied
to the Building
Industry
Nano-material Solution + Polycarbonate
• Polycarbonate sheets : €100/m²
• Nano-material cost : €67/m²
Total cost
Energy savings
Versus Double-pane Glass
• Glass, profiles : €300/m² €435,000
• Shaders
€130/m² €188,500
Total cost €430/m² €623,500
Savings
€263/m² €381,350
Immediate payback
+ €5,000/year on energy
€167/m²
€145,000
€ 97,000
€242,000
€3000/year on lighting
€2000/year on heating
Versus PC without nanomaterial
• Polycarbonate sheets : €100/m² €145,000
• Shaders
€130/m² €188,500
Total cost
€230/m² €333,500
Savings
€63/m² €91,500
Immediate payback
+ €5,000/year on energy
Results
Nanotech Materials for Truly
Sustainable Construction
Results
Natural daylight evenly dispersed inside the building
No glare, no shadow, no “light tunnel” issues
High comfort level for the players and spectators
A new way of thinking
 Photocatalytic cement with TiO2
 Self cleaning
 Removes pollutants in area around building (CO2, NO2,
etc.)
What is Nanogel?
Aerogel resists the transfer of heat, making it a great insulator.
Nanogel Performance
- Unsurpassed thermal insulation
- R-value of 8 per inch / U-value of .64W/m²K per 25 mm’
- Increased natural light transmission
- 75% per 3/8 inch / 80% per cm
- Superior light diffusion – elimination of glare
- Improved acoustic performance
- Reduced solar heat gain/loss
- Decreased energy consumption – heat, air conditioning,
lighting, ventilation, carbon emissions
- Unmatched moisture resistance – 100% hydrophobic
- Exceptional color stability and insulation performance
Size Spectrum of Environmental Particles
Nanoscale contaminants in
water and air (little is known)
H2O
(0.2 nm)
Hemoglobin
(7 nm)
Microbial Cells
Virus
(~1 µm)
(10-100 nm)
Protozoa
(>2 µm)
Conventional Filtration
Microfiltration
Adenovirus 75 nm
Ultrafiltration
Bacteriophage 80 nm
Reverse
Osmosis
Influenza 100 nm
E. Coli
0.1 nm
1 nm
10 nm
100 nm
Fullerenes, nanotubes
1 µm
PM 2.5
Aerosols
10 µm
1000 nm
100 µm
Pollens
(10-100 µm)
After Wiesner
WWW.EPA.GOV/NCER Go to Publications/Proceedings
OZONE AND
NANOTECHNOLOGY
Ozone Layer Depletions
In the 70s it was discovered at the University of
California
Actually, it is not a hole but a decrease of the ozone
layer’s thickness
In the equatorial regions where the ozone layer
always has been thinner, this decrease is more
obvious.
The Problem
The ozone hole grows and decreases every year
with the stations, disappearing slowly as the
south hemisphere reaches the maximum of his
summer.
Climatic Factors
temperature
Rainfalls
Why is The Ozone Hole Continue to GROW UP Since
Montreal Protocol (1987) Small groups of the
Chemical Industry, knowing that refrigerants will be
banned, started to produce more. So, from 1990 to
1995 it was produced more since refrigeration with
CFC’s started.
CFC’s substances take a long time (10-15 years) to
reach the ozone layer’s level
CFC’s (Freons) were invented in the 30s.
The most commons are CFCl3 (freon 11), CF2Cl2 (freon 12),
C2F3Cl3 (freon113) y C2F4Cl4 (freon 114).
DESTRUCTION PROCESS
Release chlorine of certain stable compounds, which is attacked
by the
intense UV radiation, can strip of an atom to the ozone molecule
giving rise to ClO and normal oxygen. Each molecule of CFC
destroys thousand
and thousand of ozone molecules.
As they are not very reactives, CFC’s spread slowly (it takes years)
towards the stratosphere without undergo changes; there they
decompose because of the UV radiation of λ=175-220nm
Despite the fact that the growth-rate of ozone
depletion potential (ODP) in the atmosphere is
starting to drop, without Molecular Nanotechnology
(MNT) the impact of ozone-depleting substances
(ODS) on stratospheric ozone will continue.
ODS refrigerants can be replaced with MNT → The
growth-rate of ODP in the ODS reservoir will become
zero.
Drexler proposed using sodium-containing balloon
type nanobots
The nanobots, powered by nano-solar cells, collect CFC’s
and separate out the chlorine in the stratosphere.
Combining this with sodium makes sodium chloride.
When the sodium is gone, the balloon collapses and
falls. Finally, a grain of salt and a biodegradable speck fall
to Earth. The stratospheric CFC is quickly removed.
There can be used also nanobots containing
otherbmetals (Ca, Mg) to remove stratospheric CFC.
Among ODS, halogens other than chlorine (Br) could be
neutralized using this tecnique.
Metal Nanoparticle Solution to Ozone
Depletion
What are the materials of nanotech?
Nanostructure
Size
Example Material or
Application
Clusters, nanocrystals,
quantum dots
Radius:
1-10 nm
Insulators, semiconductors,
metals, magnetic materials
Other nanoparticles
Radius:
1-100 nm
Ceramic oxides, Buckyballs
Nanowires
Diameter: 1100 nm
Metals, semiconductors, oxides,
sulfides, nitrides
Nanotubes
Diameter: 1100 nm
Carbon, including fullerenes,
layered chalcogenides
Jortner and C.N.R.Rao, Pure Appl Chem 74(9), 1491-1506, 2002
Nanomaterials have unique properties
How can these properties be used to protect the environment?
Characterizing Nanomaterials
Applications of Nanotechnology
Applications of Nanotechnology
VDI
The Challenge
Use nanotechnology research to:
…Help clean up past environmental damage
…Correct present environmental problems
…Prevent future environmental impacts
…Help sustain the planet for future generations
The future of is here now
•
•
•
“Because of nanotechnology, we will see more
change in our civilization in the next thirty years
than we did during all of the 20th century”
- M. Roco, National Science Foundation
Resources
 Material Connexion, Beylerian & Dent (Wiley, 2005)
 Material Architecture, Fernandez (Oxford, 2006)
 EU Nanoforum Report (December 2006;
nannoforum.org)
 Transmaterial, Brownell, (Princeton, 2006)
 Material World 2, MateriO (Birkhauser, 2006)
 Extreme Textiles, McQuaid (Princeton, 2005)
 The Dance of Molecules, Sargent (Penguin, 2006)
 The Nanomaterials Handbook, Gogotsi (CRC, 2006)