The course is divided into three sections. After introductions in
week 1, the first section, from weeks 2-5,
centers around kinetic energy and converting it into electricity. It
culminates in a the presentation of small, kinetically-powered
electronics projects in week 5.
In the second section, we examine solar technologies, focusing on
photovoltaics (PV) in
detail. We will apply many of the same measurement techniques and
that were introduced in the kinetic section. The section ends
in a presentation of BEAM-inspired solar projects in week 9.
At the end of Section One we will form groups for the final project to
presented in weeks 13 and 14. Some class time in Section Two, and most
of Section Three, will be dedicated to developing these projects.
Note: Because of the snow day
1/27, and another week (3/3) that I will be away, this semester's
schedule has become a little complicated. To help sort this out, I've created a working calendar here.
This now has all final dates!
Class 1: Introduction In which
we get to know more about one another, the class, its origins, and its
ITP is an interesting context in which to think about energy. Most of
your projects here have an on button
- they are active energy consumers. The things you create may help to
make technology irresistible and an increasing part of daily life; the
consequence of the on button is magnified. But exactly because of
what you do at ITP, you are in a good position to understand energy in
a precise and nuanced way - an understanding generally all too lacking.
In this first class we begin the process of looking at the world - from
the scale of an
individual electronics project to the scale of the universe - in terms
of energy and its various forms and conversions. We introduce (or
reintroduce) some of the few terms and units we will
rely on throughout the semester: watts, joules, work, power.
The first class serves as an introduction to some of the larger
themes we will pursue over the course of the semester. We look at the
origins of the course and the relevant parts of my background, and hear
from you about your experience and expectations.
An excerpt from Vaclav Smil's earlier work:
Energies: An Illustrated Guide to the Biosphere and
Civilization. 1999, MIT Press, online here
In this section we will learn to
quantify energy in the physical world and ground it in terms of our own
bodies' capabilities. We will see what considerations affect the design
of electrical generators. We create circuits that condition electricity
from typical kinetic converters, and we review methods for measuring
electricity, applying these to measuring power and energy. We will
gain experience with our first electrical energy storage device, the
capacitor. While the central theme here is kinetic energy, much of what
we learn in these weeks will apply to solar (the focus of the Section
2) and any other energy technology.
Class 2: Kinetic 1, Conversion In which
we discuss mechanical work and power, heat, mass, and magnetic
Most of the work of the world involves moving things (from atoms to
bits) from one place to another (and sometimes we heat them up). Almost
all of the electricity we use was generated by moving coils of wire
through magnetic fields.
In this class we'll look at some of the physics behind
kinetic and gravitational potential energy. No converter will yield
more power than is put into it, so we need to be able to characterize
the input to our devices. This will also let us look at claims made in
the media and elsewhere as to the viability of human-based
kinetic-electrical conversion. We'll examine the history of the
concept of heat, and make our own electrical generator for converting
metabolic chemical energy into electricity (bonus question - is this a
the open-circuit voltage and short-circuit current of your converters.
Put together a circuit that powers a small load, such as an LED. If
necessary, use rectification, smoothing capacitors, and voltage
regulation. Begin to characterize the energy and power you might be
able to expect for your kinetic projects.
Class 3: Kinetic 2, Conditioning Having
made a little electricity, we ponder what to do with it.
It is unlikely that our kinetic
converters from the previous class
can directly drive a useful (or even useless!) electronics project. In
this class we'll look at ways of rectifying, smoothing (short-term
storage), and otherwise conditioning the electricity from those
While our in-class and project
work focuses on bodies as sources of
kinetic energy, this week we'll look at the larges renewable sources of
kinetic energy: wind and hydro power. In both cases, the kinetic (for
wind) or gravitational potential (for water) energy is converted into
electricity via large versions of the same things we're doing in class.
The ultimate source of both hydro and wind power (and for the muscle
power we feed to our kinetic converters) is the sun.
For background reference
on magnetism and induction, see this entry in the excellent Cartoon
Guide to Physics by Larry Gonick
and Art Huffman. Note in
particular how Lenz' law relates to the conservation of energy.
haven't already, finalize any conceptual aspects of your kinetic
project - as in, at this point you should know what you are trying to
do. Use the real power worksheet and the capacitor charging method to
measure the real world power of your generator. Obtain any materials
you need to finish your project this week.
An animated guide
to diodes and rectification. (link thanks to Eric Foreman).
NPR's site on the US
electricity grid. How much electricity comes from magnetic
induction? How much of that is driven by heat engines?
Class 4: Kinetic 3, Storage and Measurement, Capacitors Having
conditioned our electrical generators, we use them to charge a
capacitor, and use this, in turn, to evaluate the power of our
Capacitors are a fundamental electrical component. They are
extremely simple - just two conductive plates close to each other but
separated by a non-conductor - yet this simple arrangement has the
ability to store electrical charge and can be used like a very simple
battery. We will look at them as our first means of storing electrical
energy. However, compared to other means such as batteries, the energy
density - Joules per unit of volume - and specific energy - Joules per
unit of mass - is low (although many hope this will change).
Despite big energy shortcomings, capacitors have some
advantages: they are simple to charge and discharge, and both can be
done quickly (very high power in and out), they have high cycle life
expectancy, and the energy stored in a given capacitor can be easily
determined as a product of its capacitance and voltage. We will exploit
this last property to use capacitors as a means of quantifying, in
real-world measurements, the performance of our kinetic converters.
Solar energy is the only external source of energy for our planet.
Except for geothermal (residual heat and fission of earth elements),
nuclear (more fission and potentially fusion),
and tidal energy (a slow transfer of momentum between the Earth and
Moon), the sun drives processes on the planet ranging from the
metabolism of single celled organisms to the weather. We will look at a
range of historical and modern technologies for harnessing this energy,
and focus specifically on photovoltaics (PV), the direct conversion of
light into electricity. We will work with another
electrical storage device - the rechargeable battery.
Also, use spring break to think about final projects for the class.
Come back ready to pitch two projects. Keep in mind the resources,
particularly solar (small and arge portable kits, etc) that the
department makes available for you.
We'll work in-class on a simple kind of solar engine (SE)
called the Miller engine that you may be using in your BEAM projects.
I've posted photos of all the
circuits seen in class this week on Flickr here.
Schematics all follow the BEAM documentation online, with the important exception of this circuit,
which uses the 3812S monitor available from the school. This chip is
similar to the 1381/TC54 except it has an inverting output. No problem,
but we have to switch to a PNP transistor between the V+ and load.
Alex: Microbial Fuel Cells and Glucose Bio Fuel Cells
Chemical reactions can move electrons - this is the basis for
batteries and fuel cells. If the reactions are reversible, electricity
from other sources can be stored this way, too. We'll look at batteries
in detail this week.
Work on your BEAM
and the terrarium. Finalize your final project idea (select from
options if you've been considering several). Give your project a name.
Snazzy is good. Determine what "success metrics" should be applied to
We'll see all the BEAM bots in this class. You will also present final
project concepts and progress reports.
a one-slide summary of your project to present in class next week.
Include an overview of the concept and an outline of what you will
build and present. Include the name and metrics you developed for this
week. Obtain any final materials you will need for your project and
bring those to class too.
Section Three: Final Projects
Class 10: Field work
If possible, we'll take ITP's solar resources outside to get more
familiar with them.