Randy Chambers: Using Renewable Energy and Environmental Sustainability at the College of William and Mary

1. Electricity, Work, and Power — An Introduction and overview.

Fruits and vegetables class! Started with a banana, talked about calories and watts, leading to discussion of energy required to maintain a human. Compared energy for human maintenance to energy needed to power a light bulb. Moved to electricity and voltage, used limes to generate voltage (showed Big Bang "Potato Clock" video with Bob Newhart). Played with electricity and voltmeters, electromagnets, and the world's simplest motor. Lots of hands-on demos that got students working and observing together, to become familiar with energy, work, and power.

2. Passive Designs for Optimizing with Nature — Smart building designs to conserve energy

Talked about the energy needed to heat and air condition buildings, then experimented with the heat retention of different types of building materials. Students considered the placement and orientation of buildings and windows relative to solar fields and shading. Using GoogleMaps, we examined the current distribution of buildings on campus and discussed what we thought would be the relative HVAC costs for each building. For planned construction projects on campus, we discussed what passive designs might allow the College to minimize heating and cooling and lighting costs.

3. Using Wind to Do Work — Boats, windmills, and wind turbines

I had to modify this module to fit my campus. We do not have sailboats, but we do have a campus lake and canoes. Students canoed on the lake and used different foil designs to use the wind to power their canoes. Back in the classroom, we looked at US wind field distribution, then focused on our state. We then went to a website that calculates construction costs and energy returns for wind turbines for a given wind field. Based on these calculations, we determined the folly of attempting to use wind turbines on our campus.

4. Thermal Energy from Light — Solar collectors to heat water and buildings

Students are attuned to heat from the sun but most have not used solar to heat water or buildings. Outside, we used Fresnel lenses to concentrate solar energy sufficient to start small fires—of course students loved this exercise. We also measured temperature changes in opaque versus clear containers to demonstrate light absorption versus reflection and the conversion of light energy to heat. Although we were able to cook marshmallows, the class time was too short to complete cooking of other foods.

5. Creating Electricity from Light — Photovoltaic and solar-thermal generation

We used small PV units outdoors to demonstrate conversion of light energy to electrical energy; showed the modular construction of the PV cells, then went indoors to discuss how PV "works." Talked about the energy yield from PV cells and calculated how much area on campus would need to be covered by PV to satisfy the current energy needs of the college. Eye-opening exercise!

6. Better Ways to Illuminate — From incandescent to fluorescent and LEDs

This short, hands-on lab allowed us to compare the relative energy requirements, lumen yield, heat production, and payback periods using different types of light bulbs.

7. Hybrid and Electric Cars — Conversion and storage of electrical energy for transport

The history of how cars are powered is fascinating, since 100 years ago cars were powered by gas, by steam, or by electricity. One hundred years later and cars are powered by gas and by electricity, still! Moving from fuel efficiency to the "new" hybrids to the Tesla to hydrogen fuel cells. Not many outdoor demos possible here, unless you have a small class . . . and a Tesla! Students enjoyed a lengthy in-class discussion of different power options and where they think modes of transportation are headed.

8. Biomass Burning — CO₂ in and CO₂ out

We used a few local examples to consider biomass as fuel. First, we thought about our campus forest and how much wood was available to burn. How long could our campus heating needs be satisfied by our local supply of wood? Then, once that forest was harvested, could we plant corn to generate ethanol as a fuel? Could we grow algae in the campus lake to provide lipids for biodiesel production? Could we harvest methane emitted from the anoxic bottom of our campus lake to provide energy? This led to a series of short calculations to determine the energy yield possible from all these local, potentially renewable resources. Informative and fun.

9. Energy from and to Earth — Geothermal energy and ground exchange HVAC

Students increasingly are familiar with ground exchange HVAC, and some have it at their homes. We do a simple exercise running cold water through coils of Tygon tubing buried in heated sand, to demonstrate how heat is exchanged in the water (the final temperature of water exiting the coils is much warmer). For geothermal issues, we discuss the location of hot spots, the source of hot rocks and their distribution and depth, and how that heat energy can be used (i.e., hot water for heating, electrical generation, etc.).

10. Efficiency and Conservation are Cheap Fuels — Figuring out waste and how to control it

This seems obvious, but it is so necessary to remind students that wise use and conservation in many cases can satisfy the need for additional energy and resources. For example, we used the plot of heating degree days versus GHG emissions associated with heating fuel use on our campus to estimate the potential reduction in our carbon footprint by turning down the thermostat 1 degree.

11. Composting Toilets — Putting nutrient cycling to work

The first time I taught the course I did not use this module, and instead developed an exercise having students measure head and water volume discharging at the dam on the campus lake. Students then calculated the potential electrical energy available (very small relative to total campus electrical use, but something). Discussions ensued regarding how to use this hydropower-generated electricity. The second time I taught the course we discussed composting toilets—and whether they would work in dorms or other multi-story buildings on campus.