Posts tagged electronics

Making Your Computer Carbon Neutral

I’ve admitted it before… I love my computer, and giving it up is out of the question.  But I do understand that while the internet saves me millions of miles of travel a year and countless hours spent locating far-flung information, the computer itself uses plain ol’ polluting energy and requires a lot of rare and potentially hazardous materials in its manufacture which are as often as not disposed of improperly.  So how to green the central machine?

First up, the average of one pound of CO2 emissions put out daily by computers worldwide.  Luckily, the wonderful social, email and action network Care2 has already thought about that, and nicely offers you the option to neutralize that carbon… with a single click! And if taking 10 seconds to sequester some CO2 to offest your surfing is too much to ask, I expect to see your name in the newspaper soon, because you must be REALLY busy on something important.  Visit Care2’s Daily Click to Donate page here to ease your digital burden on the planet today, and while you’re there, click to donate to 9 other great causes like saving tiger habitat, preventing breat cancer, and preserving marine wetlands.

screenshot002

Next, consider efficiency when purchasing computer components.  It may surprise you to know that a vast majority of computer components are manufactured in one of a handful of factories in the same town in China.  One that barely even existed twenty five years ago.  To read all about it, pick up the fascinating global travel book “Confessions of an Eco-Sinner” by Fred Pearce (2008).   Though he only deals with this particular product for a chapter, the whole book is filled with amazing (and scary) tales of how the things you take for granted make it into your shopping bag.  But back to that computer… Assuming that practices amongst these competitors are relatively equal, and given that they are all run by guys who went to school together as youth this is proabably safe, you won’t gain much by purchasing an Acer over a Compaq.  That doesn’t mean, however that all manufacturers are equal.  Some voluntarily, and some in response to the European Union’s RoHS Directive which calls for elimination of certain toxic metals from their computers (see this Treehugger article for more information), computer manufacturers have started to take notice and make greener PCs.  Apple and Toshiba are notable leaders in this movement, though others are jumping onboard every day.  I’m waiting for the day one releases a totally non-toxic and recyclable computer… and while wishing, can it be compostable too?

If you’ve got your machine itself under control, there are still ways to go further, by examining the source of the energy that goes into your plug.  I’m a huge fan of surfing the web at Whole Foods Markets, because the company has a policy of purchasing renewable (wind) energy credits to offset the electricity used at each of its stores.  So when you play Tetris while eating your lunch, you’re actually helping to stimulate the alternative energy market and doing so in a totally renewable way.

Of course, they’re a popular store, so if you can’t get a seat there, you’re may be forced to strike out on your own.  There is, of course, the off-grid option of generating your own electricity with wind, solar, or micro-hydro.  These are the golden children of rugged off-griddists everywhere, and one will likely be a pretty good fit for your area.  If you don’t have the ability to install your own generation system, consider paying a little premium on your power bill for the Green Power option.  Similar to Whole Foods’ arrangement, customers who purchase green power get the satisfaction of knowing that their purchases contribute to the development of renewable energy portfolios while enjoying the on-demand power we all expect.  Or you can lease solar panels from a company that charges you a bill like any other utility but sells the power you generate using their panels back to the grid.  Solar without the start-up costs.

Speaking of power, here’s to all you night-owls out there! You see centrally generated power (utility-style) must usually be produced at the rate of greatest demand within a day.  So even though 1-5 pm is the peak power usage, at night, the generators are pumping out the same amount of juice to supply a drastically lower demand. Where does all this power go?  Some municipalities have constructed power recycling schemes, such as Los Angeles DWP’s practice of pumping water uphill at night to use for generating hydro power during daylight peak demand hours.  Other cities let this power go to waste.  That is why power use rates are so much lower at night, because utilities hope to entice people to use this cut-price power whenever possible.  So go ahead and burn a little midnight oil (figuratively of course) to take advantage of this financial reward.

Peak vs. Off-Peak

Peak vs. Off-Peak

And lastly, please, friends, recycle your computer responsibly when it reaches the end of its useful life.  Replacing single components that go bad is almost always a cheaper option than buying a whole new machine, so consider that first before declaring it dead.  But when it is, there are organizations across the globe which will take your computer, make any necessary repairs, and give it to a person in need.  Many states won’t even let you toss computer equipment legally, so you’ll be doing your civic duty, too.  If you don’t, sadly, the common practice is to let children pick through the toxic rubble of old electronics, pulling valuable metals out and stripping copper off boards in acid vats wihtout any protective measures.  It sounds like one of this “Save a child with a dollar a day” commercials, but it really happens.  Don’t be the reason little Pradeep gets cancer by the age of fifteen.

All said, the fact you can shop online rather than at retail stores, commit acts of generosity such as campaigning for social rights and making donations to worthy causes, and research innovations that make your life greener in so many ways makes the computer a world-saving tool no matter what you do to mitigate its environmental consequences.  But doesn’t doing it green just feel so much better?

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Solar Installation Class – Ohm’s Law

Okay, for all of you waiting for notes from the solar panel installation class, here’s the scoop. The first class was cool, there’s a big machine shop there, and as a bonus, we’re also going to learn about machine controls for wind systems. Nice! There promises to be lots of applied action working with actual solar panels, so I should be able to share some real knowledge of what works and what doesn’t. For those of you who’ve been with me since the beginning, we’re going to repair my solar panel (the inspiration for this blog!), too. Finally!

But of course, as with most things in life (and especially with electronics!), it makes sense to understand the science behind things before getting your hands dirty, or shocked in this case! So We spent the first class learning the basics of voltage, current, power, and resistance. Ever heard of Ohm’s Law? (Those of you having evil science class flashbacks, don’t worry, I wouldn’t share it unless it was quite necessary for your safety.) Here is Ohm’s Law for DC circuits.

P = I * E and E = I * R (“pie” and “ear” phonetically, to help you remember)

See? Simple! Only four letters! What does it all mean? Well, in a circuit, you have four things at work. First, Power. Power (the P) is measured in terms of watts. It’s the work being done using the energy in the circuit. So if you baked six pies, and your clown friend used all of them to cream the faces of his fellow friends, the power would be those six pies you made available for him to throw. When you hear talk about kilowatt hours, this is a measurement of how much power is produced and available to do work by a system. Or how much you are using, as reflected on your power bill. So, once again, that’s POWER (P).

Next up, Current. Current is a measurement of the electrons flowing through the circuit. You see, in order for the energy to get from one atom to the next in the wire, it pushes electrons down the line, carrying a charge (since electrons are negatively charged particles). This is what we think of as “flow”. Current is measured in amperes and is represented by the letter I (that’s “i”). CURRENT (I).

Third, you have resistance, which is measured in Ohms (it is Ohm’s Law, after all!). Usually, you will see resistance represented by the logical symbol R, but Ohms also have their own symbol, Ω. For the purposes of this discussion, I’ll stick to R. Resistance is what it sounds like, a measure of how hard it is for the electrons to jump from one atom to the next. It’s a measurement of volts per ampere (or how hard it is to push one electron from one atom to the next). It’s not a 100% rule, but usually, you will find that resistance stays pretty much the same in your circuit calculations. It is most affected by distance traveled, the width of your wire, and by temperature.  RESISTANCE (R).

And, lastly, there’s voltage, tying it all together. Voltage is also known as ElectroMotive Force (EMF), giving rise to the symbol for voltage, E. Sometimes you’ll see V for voltage, but here I’ll be using E. Voltage is measured in Volts (whew, an easy to remember one!). Solar panels, wind turbines, etc, are generally hooked up to 12 Volt batteries, either in series or parallel (we’ll get to that in a second), allowing you to store the energy produced by the panel/turbine. Common setups will run at either 12V or 24V, depending on application. So, rounding it all up, we have VOLTAGE (E).

POWER (P) – CURRENT (I) – RESISTANCE (R) – VOLTAGE (E)

Got it? Good. Now let’s start putting it all together. Using the formulas above, you will see that Voltage = Current * Resistance. So, when the voltage goes up, the current goes up also… they are directly proportionate. This is a VERY IMPORTANT CONCEPT in circuits. It’s the equation E = I * R, or “ear”.

The other equation, P = I * E or “pie”, is for figuring out how much power is produced by a circuit, and is equally important. Written out, it’s Power = Current * Voltage. In any given situation you’re probably going to know two out of four variables and you’re trying to figure one of the other two. With these two equations, you can always solve for the ones you don’t have already. Here’s an example:

If you know that you have a 12V battery and you need to get 72 watts of power to run your iPod, how much current do you need? By the way, current is usually adjusted by using bigger or smaller wires, because the size of the wire affects the number of electrons that can easily flow through at any one time. This is due to resistance, but I’m getting quite ahead of myself.

So using our equations, E = I * R and P = I * E, you know that E = 12 volts and P = 72 watts. So, the second equation can easily be solved: 72 = I * 12, or I = 72/12. This works out to I = 6. Since I is measured in amperes, the answer would be I = 6 amperes. If you then wanted to figure out the resistance in the circuit, you can now plug these numbers into the first equation: 12 = 6 * R, or R = 12/6, which works out to R = 2 ohms. Using two variables, you’re able to figure out everything happening along those wires!

Now let’s say you wanted to use a battery system supplying 24 volts instead. Simply substitute and do the above calculations in the same way. What did you get? Here’s the breakdown. Since E = 24 volts now, and P = 72 watts, then you should arrive at I = 3 amperes via 72 = I * 24, or I = 72/24, or 3! From there you can figure out the resistance of this circuit: 24 = 3 * R, and therefore R = 8 ohms. There is more resistance along this circuit than along the circuit running on 12 Volts, and less current.

Okay, so that’s Ohm’s Law (of DC circuits) for you! I’m a student too, so this is about as deep as I can go into the subject right now, but expect more detailed explanations and the reasons for knowing all this junk soon. Stay tuned! In the meantime, if you want to read more about Ohm’s Law and why it’s important, read the Wikipedia article here.

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Meet my solar panel~

Aaron Cake’s Converter http://www.aaroncake.net/circuits/inverter.asp

I decided to start my experiment by figuring out how to convert the power my solar panel will one day generate into usable power for my daily activities. First stop: the DIY version at the web link above. Um, yeah. Way over my head (and it seems it’s over everyone else’s on that site too. It’s their most popular “help” topic!) Makes spending $75 for the version from the store seem all that much more attractive. I think I’d blow up at least that much in equipment trying to get this to work. For all of you electro-philes out there though, this is a nice site with descriptions of tons of gadgets I could never hope to successfully build.

When I picked up my solar panel, which the guy gave me with the caveat that it wasn’t working due to a voltage drop, he suggested that maybe I could slice apart the panels and charge smaller batteries instead. Since my goal is still to use them as a whole, so that I can deal in 12V current and not have to create a voltage understanding nightmare (this statement alone may proclaim me an electronics newbie, I have no idea), I decided to give the panel a good looksie and see what there is to work with. The panel is composed of about 18 individual panels, set up in a series circuit. Here’s a little diagram:

The Circuit

They output to a little box on the back with two wires. One for each battery terminal, I have to assume. The clear vinyl(?) covering on the panels has started to peel back, and the aluminum frame is disassembled from where the former owner tried to attack the voltage drop problem. Around the edges is a strip of what looks like aluminum foil, keeping all the layers together. So, first thing I did was get rid of it. Sure hope that’s not part of what makes it work! Next to go will be the clear covering, once I find a suitable replacement, because it’s dirty and peeling. Any suggestions on a good material?

I did receive an auspicious sign this morning, one that let me know going solar is definitely in my future: As I was walking down the street, thinking about what the best use for that panel would be, someone had put a roll of solder wire on top of their trash can for the taking. In city-slicker Los Angeles. Oh, joy! If you think dumpster diving is wrong, well, you and I probably won’t have much in common. I take my blessings where they come, and finding free and recycled parts for my experiments is definitely always a big one. So, the rest of today will likely be spent digging through my toolbox to find my old soldering iron. Looks like this solar panel’s gonna get a make-over after all! See you soon~

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