Advice for Solar Classroom Project?

Re: Advice for Solar Classroom Project?

bbt,
unfortunately that $1000 will not go very far for photovoltaic (pv) applications. even if your budget was larger you would need a large closeby area outside to mount the pvs. moreover, you don't want them to be accessed easy enough that they could be easy to steal. it may be possible for you to demonstrate the general principles on a smaller scale. you won't be grid-tied as that is for bigger budget systems so that takes some cost out of the equation, but there may be provision for further available monies depending on your location. check your location on www.dsireusa.org some items are sensitive to modified sinewave inverters such as some chargers, wall worts (wall adaptors), and anything with an electric motor, but you don't have to have 120vac for everything so if you can have 12v items to run on this, this greatly reduces costs even more as you will eliminate the inverter's needs.
the pv costs can be great and a solar controller (regulator) and a battery will be needed to run most things. here is the link to more info and the store for the forum's host northern arizona wind & sun.
http://www.solar-electric.com/
there you can see the costs involved just getting together a fairly basic system. i did not mention some of the other items needed such as the pv mounts, the wiring, fuses or breakers, disconnects if applicable, combiners if applicable, and an ammeter and voltmeter (some controllers have this built in) to show voltage relationships at various stages and that a charge or load current is flowing depending on its placement in the general circuit. if you have a electrical or electronics class in the school or the school district, you may wish to consult with those teachers as well on this subject depending on how far you'll go with it and to have somebody right there with electrical knowledge. i hope i'm not overlooking anything, but i'm quite sure if i do that others will have my back. here is an outline of the simplest system in a simple form:
mounted pv(s)>wiring>combiner + fuses or breakers and disconnects>solar controller>wiring>fuses or breakers>deep cycle battery(s)>fuses or breakers and disconnect>wiring>to either the 12vdc loads or the inverter to run 120vac loads.
i do recommend reading up in this forum for your own education on the subject particulars, but you will not learn all aspects in time for class to begin so this may need to be sped up somewhat and have somebody with electrical knowledge around to help with some particulars in order to avoid some time consuming back and forth correspondance or oversights as we can't see what you see.
i hope this gets you started at least in a general sense with more particulars to come after your further questions and feedback to us for sure.

Re: Advice for Solar Classroom Project?

you're quite right bill as there are other ways to collect solar energy and the thermal panels they can see results with too. even a coffee can painted flat black in the sun will heat water quite well and thermometers are cheap, but the infrared thermometers are really easy to use and avoids any possible burns. many do say the sun is in the winds and waters as it is their initial driving force, but we do talk of it as a different source only because of collecting that energy is radically different enough to warrant it.
you did spark a few school memories for me as my science teacher in jr. high did have a homemade hand generator. i remember cranking it to keep a 60w bulb lit. it's hard work. even the physical therapy i did (and still need to do excepting travel and cost woes) had a machine that was hand cranked and it contained a generator and i would suppose a resistive load inside and gave a digital readout in watts of the power produced. turning that thing for 8 minutes while maintaining 100w or better is alot tougher than many people think. i wish i had that machine as my battery would be the new load for it and give me more incentive for a therapeutic workout.8)

Re: Advice for Solar Classroom Project?

I gave a presentation in a local elementary school this May.

A lot of the material was just getting the students acquainted with energy in general. That included "What can you do with 1 kWh?" (power your iPod for 2 months, ride 100 miles on an electric bicycle, ...), "How much power is there in sunlight (about 1 kW per square meter, bright sunlight), "How much does 1 kWh cost from the power company?" (fill in your number, the cheapness is likely to surprise them).

I shared a little of how our family installed our own photovoltaics (depending on your community, you might find someone nearby who did this. Most owners are eager to talk about their systems.)

I also brought in a full-size photovoltaic panel intended for grid tie. I had connected a 24-volt fan to it, so they could see the effect on fan speed if they shaded the panel. It also sparked their imagination that this one panel would be enough to make an electric bicycle with unlimited range, "you could go all the way to the other coast, as long as the sun was shining". Panels are expensive, but you could find a small 3-watt or 10-watt panel to do a demonstration, and just show pictures of larger ones.

Others have already mentioned solar heating examples. A fun thing to do might be to bake soft cookies in a solar oven.

You might even work in electrolysis of water somehow.

Re: Advice for Solar Classroom Project?

How about a "this or that" demonstration? Maybe set up a small water pump (use one of those battery powered indoor meditation fountain pumps), a light bulb, and maybe a small millstone or some other work piece. The three items should be easily managed by a very small, project sized solar panel. Also set up a very small traditional power system, maybe a small wood fired boiler that will drive a small project-sized generator, that is strong enough to run these things. The whole thing would fit on a desk in a display box. You could fire up the boiler and show how traditional power is made, and let the kids smell the smoke (maybe use some of that wood that has a nasty smell to it), put a filter over the smoke stack to collect a sample of what the wood fired boiler is emitting, and show pictures of boiler explosions, and show the ash that is left over after the fuel is burned. You could also set up a small hydro or maybe a small wind generation setup, and show how a combination of wind, sun and hydro can provide clean power as opposed to the polluting sources. This would show in real life the stark differences between clean and dirty energy, in a way the little buggers can understand. It's one thing to talk about it, quite another to see a clean filter get dirty and see the debris that remains. Using miniature, project sized components would likely get the whole thing in under 1000 bucks. Best of all, a PV panel can run off the light from a standard flourescent light bulb, so you'd not need to worry about being near the sun. Might have to get a larger panel than you'd need to actually make it work in sunlight, but it'll work.

EDIT - Found another possibility at this site on evacuated tubes. The last item on that page is a test setup for 150 bucks, designed for salesmen to demonstrate how evac tubes work. Would also work for a classroom, but this one would require being outside to work, unless you could somehow simulate actual sunlight in the classroom. Don't know if a light bulb would work on this one or not.