Greengineering

October 28, 2009 6:45 PM

Save Our Planet Filter: My girlfriend is doing a "green energy" engineering project and needs inspiration. This is a project for an electrical engineering class in college so give us your coolest ideas for green energy projects.

The project is supposed to interact with the public - something that could be put on display in an exhibition, a museum, college campus, or anywhere public. Additionally, it must educate the public to "think green" and raise people's awareness of green energy sources.

The description is pretty vague and can be pretty much interpreted in any way she wants, except it MUST provide some sort of user input and some sort of feedback to help the user understand something about green energy sources (solar, hydroelectric generators, wind turbines, or any other means of electrical generation or efficiency.

An example that was given was to have a solar panel on display, and have people put their hands over the solar panel to see how the energy generation of the panel changes with shadow in the way, using a little display. The professor likes this idea because it is educational and it gives back feedback.

Another example that was given to her to inspire her was a public trash compactor that uses a solar panel as its energy supply. Obviously this is a much bigger project and needs some sort of twist to be "educational", but it's another way the assignment can be interpreted.

She's got about a 50 dollar budget for electronic parts and about 7 weeks to complete this, so it's not a huge project, but still worthy of an electrical engineering major. She feels most comfortable working with (small!) solar panels, but is interested in all areas of "green electricity".

So, if you could ask someone to design an interactive electronics project that is green and educational, what would you ask them to create?

posted by thekiltedwonder to science & nature (11 comments total)

What is measured is managed:

I want a dimmer switch that I can put on my wall that shows how much electricity my lights are using as I dim them up and down.

Similarly, it would be nice to have a wall outlet cover with a built-in current meter. Sort of like a kill-a-watt, but something that is permanently built in to the structure of my home to show me any time all the time how much electricity is being used by something.

posted by alms at 7:03 PM on October 28

This isn't quite right, but I've been wanting an iPhone/BlackBerry app that lets a person type in an item for disposal and the app would say whether it should go into recycling, compost, trash/landfill, specialty disposal (e.g. batteries), and the local location for each sort of disposal. There must be some similar app for green-engineering -- what uses less energy, X or Y, that sort of thing.
posted by ClaudiaCenter at 7:26 PM on October 28

Solar panel that tracks the sun (or available light source) to maintain optimal orientation.
posted by Behemoth at 7:34 PM on October 28

Take a motor or something similar that requires a reasonable amount of energy to run and gives some sort of feedback as to how well/fast it's working (e.g. with a spiral disc on the shaft).

Have your 4 or 5 alternate forms of energy; solar, hydro, wind, nuclear, coal, &c. Research the real-world the 'greenness' (CO₂ output?) of each. Mock up as many as possible on your display - solar can be a solar cell under a light, hydro can be a little waterwheel, wind can be a small turbine powered by a fan, &c. - so that the user can vary the output of each (e.g. dim the lamp, turn a tap to slow down the water, turn a knob to slow down the fan, etc. Bonus points, if you can manage it: have the solar cell powered by ambient light, and the wind turbine powered by the breeze.

Now, have a slider for each form of energy, so the user can mix and match the source feeding the motor. From the slider position, derive a display - bargraph? - showing the total 'greenness' of the chosen mix of power. Make the aim of the display for the user to keep the motor speed constant while maximising 'greenness', while the real-world (sun, wind, rain) conditions vary.

You could take this much further - automate the sources to track monthly variations in each factor, simulate that over a year, and give the user a score at the end of the year?
posted by Pinback at 7:34 PM on October 28

A lot of ideas are going to be hampered by scale -- a small solar panel, for example, would take days or weeks to harvest enough energy to compact a respectable amount of trash; a pinwheel-sized wind turbine that visitors blow on is also going to (probably) not generate enough power to even light an LED in real time. Small-scale energy mockups run the risk of sending the message that it's impossible.

One idea I've always wanted to see built would be a green-energy counterexample. If you used an off-the-shelf heat engine and built an attachment to generate elecricity, you could keep a 100W light burning for a 10-hour workday by using 1/2 kilogram of coal -- about half a liter, or just a bit smaller than a standard 20oz Coke bottle. That's assuming you can be as efficient as commercial power generators (about 30%); you'll probably need to burn more.

That would seem (to me) to be a good combination of "pretty substantial pile of coal" with "holy crap there are light bulbs everywhere" and would help make the broader point that we're burning an awful lot of it every day.
posted by range at 7:50 PM on October 28

I like alms' idea. Dead simple conceptually, but still hard work to make it elegant and well designed. Even a whole-house power meter to be mounted in the kitchen is good.

She can use zigbee or what have you to do the handshaking from the sensor to the display, which adds a bit of needed difficulty, instead of 'hey look, it's an ammeter!'
posted by sebastienbailard at 7:59 PM on October 28 [1 favorite has favorites]

I'd love to see some kind of wind turbine rig that Average Joe Homeowner could buy at a hardware store and install on their roof. Clearly your girlfriend needs to design the prototype, then after she graduates she has to start up the company that will make them.

For educational purposes, you could attach a crank so people could turn the thing by hand to see how fast it needs to spin to light up a light bulb, or whatever. People really underestimate how much power it takes to run stuff, until they have to supply the oomph with their own muscles. Not so much thinking green as thinking at all about energy, and how much we use all the freakin' time. But that leads right into thinking green, so it's a good start.
posted by Quietgal at 8:00 PM on October 28

I'd love to see some kind of wind turbine rig that Average Joe Homeowner could buy at a hardware store and install on their roof. Clearly your girlfriend needs to design the prototype, then after she graduates she has to start up the company that will make them.

Problem is, they're greenwashing; they don't pay for themselves carbon-wise in urban areas with windshadow. You want a big honking one, especially out in the fields.
posted by sebastienbailard at 8:09 PM on October 28

Build a 90+% energy-efficient Class D amplifier and pair it with a high-sensitivity speaker (96 dB or so with the first watt).

Then obtain a standard stereo system. Usually only 30% energy efficient, and only gets you maybe 85dB at one watt.

Compare the energy draw of the two systems playing loud music. One will be drawing 1-4 Watts, the other 30-50-100W and up.

If you select the right Class D amp and the right speaker, for example a Tripath amp chip and a Fostex speaker, the energy-efficient system will even sound significantly better.
posted by krilli at 8:13 PM on October 28

A number of people have mentioned solar PV. What about solar thermal electric generation? Cheap (good for her project budget and for citizens wanting to copy her), uses much less in the way of scarce/toxic materials (better for the environment), and not commonly seen (distinguishes her from her peers).

An early innovator, Frank Shuman, built a solar-thermal plant in Cairo around 1910 that was somewhere around 40% efficient. His design used water to transfer heat from the absorptive surface to a boiler filled with some liquid with a much lower boiling point (ether?). Mirrors were used to focus light on the absorptive surface. The resulting low pressure system was simple and robust. As far as I've seen, current solar thermal electric projects now use extremely high temperature focal points. The low temperature, low pressure approach pioneered by Shuman seems great for neighborhood level projects, demonstrations, or backyard science projects.

You can have the standard goofy demonstration to show that blocking sunlight from the collector. You can also have pamphlets demonstrating how it is a DIY project for anyone with moderate mechanical skills.
posted by Derive the Hamiltonian of... at 11:07 PM on October 28

You could add in PV to krilli's idea to make it renewable and also portable.
posted by biffa at 4:34 AM on October 29