High School Chemistry November 10, 2010

1. WELCOME
TO
CHEMISTRY
1Instructor: Mrs. Balla HSChem_2010Nov10

2. Let’s
Discuss…
Storing
Solar Energy
Indefinitely
Instructor: Mrs. Balla HSChem_2010Nov10 2

3. Instructor: Mrs. Balla 3
Introduction
 We all know about solar thermal and solar
photovoltaic energy, but MIT (Massachusetts
Institute of Technology) is coming back to a
solar energy idea that was dreamt up decades
ago but left on the bench due to our inability to
gather and make use of it in a practical and
economical way.
 “This is the thermo-chemical approach, in
which solar energy is captured in the
configuration of certain molecules which can
then release the energy on demand to produce
usable heat,” David L. Chandler of MIT reports.

4. Instructor: Mrs. Balla 4
 The big advantage of this approach is that
the heat-storing chemicals used can store
the heat for years.
 In the normal solar-thermal approach, even
with a lot of insulation, heat leaks out.
 Additionally, the process is reversible in
this approach and the energy can be easily
transferred from one place to another.
 So, it can be collected in a place ideal for
collecting the energy but then used
wherever needed.
 http://cleantechnica.com/2010/11/08/storing-solar-energy-indefinitely-new-
energy-storage-approach-from-mit-
video/?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A
+cleantechnica+%28CleanTechnica%29

5. Instructor: Mrs. Balla 5
 In an extreme example demonstrating this
approach’s advantages, Jeffrey Grossman, the Carl
Richard Soderberg Associate Professor of Power
Engineering in the Department of Materials Science
and Engineering, said: “You could put the fuel in the
sun, charge it up, then use the heat, and place the
same fuel back in the sun to recharge.”

6. Instructor: Mrs. Balla 6
 Here’s a little more history on the thermo-chemical
approach and MIT’s recent breakthrough:
◦ Researchers explored this type of solar thermal fuel in the 1970s,
but there were big challenges: Nobody could find a chemical that
could reliably and reversibly switch between two states, absorbing
sunlight to go into one state and then releasing heat when it
reverted to the first state.
◦ Such a compound was discovered in 1996, but it included
ruthenium, a rare and expensive element, so it was impractical for
widespread energy storage.
◦ Moreover, no one understood how the compound worked, which
hindered efforts to find a cheaper variant.
◦ Now researchers at MIT have overcome that obstacle, with a
combination of theoretical and experimental work that has revealed
exactly how the molecule, called fulvalene diruthenium,
accomplishes its energy storage and release.
◦ And this understanding, they said, should make it possible to find
similar chemicals based on more abundant, less expensive
materials than ruthenium.

7. Instructor: Mrs. Balla
7
 The problem is still finding an alternative
to the very rare and expensive (element
ruthenium, but the researchers from this
project are much more hopeful now that
they can find an alternative.
 According to Grossman, the next step is
“to use a combination of simulation,
chemical intuition, and databases of tens
of millions of known molecules to look for
other candidates that have structural
similarities and might exhibit the same
behavior.”

8. Instructor: Mrs. Balla 8
 Basic Information of Ruthenium
Name: Ruthenium
Symbol: Ru
Atomic Number: 44
Atomic Mass: 101.07 amu
Melting Point: 2250.0 °C (2523.15 K, 4082.0 °F)
Boiling Point: 3900.0 °C (4173.15 K, 7052.0 °F)
Number of Protons/Electrons: 44
Number of Neutrons: 57
Classification: Transition Metal
Crystal Structure: Hexagonal
Density @ 293 K: 12.2 g/cm3
Color: silvery
Number of Energy Levels: 5
First Energy Level: 2
Second Energy Level: 8
Third Energy Level: 18
Fourth Energy Level: 15
Fifth Energy Level: 1
 Facts
Date of Discovery: 1844
Discoverer: Karl Klaus
Name Origin: From the Latin word Ruthenia (Russia)
Uses: platinum alloys
Obtained From: pentlandite, pyroxinite

9. Review
Instructor: Mrs. Balla
9
1. What is the thermo-chemical approach
to solar energy storage?
Solar energy is captured in the configuration of certain
molecules which can then release the energy on
demand to produce usable heat.
2. What is the big advantage of this
approach?
The heat-storing chemicals used can store the heat for
years.

10. 3. Is the process reversible?
yes
4. Can the energy be easily transferred from
one place to another?
yes
5. How long has been this research been
going on?
since the 1970’s
Instructor: Mrs. Balla 10

11. Questions? Questions? Questions?
11
What’s
on
your
mind?
Instructor: Mrs. Balla

12. Questions? Questions? Questions?
What was
the best part
of your
Science lesson
this past week?
Instructor: Mrs. Balla 12

13. Questions? Questions? Questions?
What
are the challenges
that you had
this
past week
In Chemistry?
13Instructor: Mrs. Balla

14. Questions? Questions? Questions?
What
Chemistry
topic
will you
be working on
this
coming week?
14Instructor: Mrs. Balla

15. Questions? Questions? Questions?
What
Chemistry
topic
would you
like to know
more
about?
Instructor: Mrs. Balla
15