Posts tagged practice

Solarious, the Sequel

It all started with a plan to get a little real-world experience in green. I was going to learn how to use a solar panel, and maybe hook one up to the place where I live, achieve true energy freedom, and hopefully help a few mega-corporations forget my phone number in the process. It felt innocent, idealistic, practical even. So I started Solarious here to follow the journey and catalogue some of the things I learn along the quest for self-sustainability. Today, almost three years later, it’s the journeys I haven’t shared here that have most greatly affected my destiny on this planet. But I’ll have to fill you in on all that later. In an effort to explore the world of green employment and a couple creative projects as well, I took a break from writing here last year. But the good news is I’m back, and could never have guessed how fast things can change even in a single 12 month period!

One major change is that green has finally gone from the niche market to the mainstream. Now I’m not arguing that adoption of policies and practices has approached the levels which it should. If anything we are like scrawny freshmen showing up for the first day of high school, ready to have our minds filled with the “answers” to life. There is so much we don’t know, both in and outside the classroom/laboratory. We are hardly even skilled at figuring out the things we have to know, much less knowing those things themselves. But at the end of that first day of school, we are at least learning that the cool kids aren’t always the established social powers, the big companies and time-honored traditional ways of doing things. No, becoming an entity of value, and not just financial value but a more-encompassing social and existential value, is becoming trendy.

This is an important moment for the “green movement”. Suddenly, you bring your canvas bags to the grocery store and no one stares you down. The farmers markets are crowded like never before if the owners of hybrid cars are an example, then anyone can be persuaded to join the green team! There is a danger posed by the level of acceptance that trendiness brings. This is the period in which society opens its ears to an idea. The people who are committed to this idea have a responsibility to carry the weight of the lifestyle they espouse. If people think that going green is about canvas bags and farmers markets and fair trade certified and recycling, then it will become something like so many movements before, a fad which fails to entertain its masters, and what an opportunity we will have lost in an age of potential.

When I started to learn about sustainable living, I was fascinated by the number of different ways in which you can change your life to become more self-reliant. It’s a little intimidating actually, when faced with the vague idea of “greening” your life. As time has progressed, I’ve come to see this area of thinking less a green movement and more one toward sustainability. Semantics, you say. Call it whatever you want so long as the job gets done. Well, I heartily agree. But in this case, the idea of green has become something quite corporate. Coca-Cola has a green division, so do BP, Walmart, and countless other behoemoth corporations who clearly don’t place doing the right thing above financial profit. No, they would not even be allowed by corporate bylaw to exist in such a state, so I feel fairly comfortable saying that efforts toward “greening” their work processes and products are largely driven by profit and little else. And there is little doubt on the surface that such a condition is less than conducive to long-term sustainability!

But this is where one must look deeper. True self-interest alone would force individuals to not drive the world down to the rims, because they still need a place to live. It is possible to be quite “green” and lead a totally unsustainable lifestyle. You buy carbon credits to offset your abnormally high amounts of air travel for work. Or maybe you bought a Prius so that your 40 minute commute each morning and evening wouldn’t make you so guilty. How about going “organic” and paying more for the privelege to eat steaks and drink exotic coffee and eat fair trade chocolate without remorse.

Hey, I do love a good Andean chocolate bar too, no need to protest. Just realize that there is a difference between being green, which is largely about taking your current habits and sprucing them up to where no one was harmed in the making of your XX so you can consume it happily, and sustainability, which means that somehow or other, we need to start living within the means of this planet and the systems which operate therein. Change is coming and it’s not going to be found all dressed up pretty with a pretty organic hemp ribbon and pricetag at a farmers market booth. No, this change, like all before and the myriad yet fated to come is going to be gritty by the terms of the day. Trust me, there is nothing sustainable about sipping a fair-trade columbian coffee and ordering the free range bison burger if that’s all you’re doing to combat the processes of inefficiency taking over our society. You thought it was “green” to buy hemp clothing. Could you MAKE that fabric from a plant?

I do understand that there is a line to be drawn in this age of interconnectivity and mass learning called the internet. You don’t have to know how to do everything, you just Google it and ten minutes later you’re a Minor Expert, whose degree from the school of everything is already in the mail. So there’s plenty of time to look that stuff up when it becomes relevant. Again, we’ve got plenty in common, no judgements here, but what would you do if your cell phone and all-access (wind-powered?) DSL plan went down and there was no internet freely available to you? How would you go about getting the knowledge you need? Don’t you think it’s time to start taking some of those steps toward knowledge now? This all sounds a little doomsday, and it’s designed to, because the aim is more about illustrating that sustainability is the true paradigm for future decision-making.

When you make a decision in your life, it’s fine to start with thinking about reducing your current burden on the planet. There’s so much that can be done in this area you could easily occupy a lifetime in pursuit of the perfect Nalgene bottle and recycled tile for your bathrooms. It’s like being a programmer and wanting to know every latest language that’s introduced to the market in a quest to be the newest greatest thing out there. Facebook may have wanted you to learn their proprietary FBML in 2008 but now they are deprecating the entire language in favor of more traditional programming language solutions. So if you spent a lot of time learning FBML to break into that lucrative user base, your time would have been better spent elsewhere, learning a language that’s useful in many applications and will stand the test of time.  It’s a matter of depth, you have to know something pretty well, and for a time, before you actually know much about its strengths and limitations.

Too many green products still go by the adage “Why have one tool when you can have two?” when sustainable thinking, like the standard language framework, are built on the priciple of “Why have two when one will do?”. So pick your battles wisely by learning about the processes underlying the actions you take for granted in your daily life. It’s a level of scientific examination for which few currently have the stomach, but it’s essential that as people in the greater public come with questions about being green, what they see is a message of sustainability, one that respects nature and our place within, one that doesn’t gloss over the issues at hand in order not to scare away potential advocates, and one being delivered by people who live whole, happy lives that just don’t happen to hurt the planet. So find a corner of the issue and start biting away at it, get to know it thoroughly. When people come asking how you did it, it will seem natural to share your journey and help them to take the leap.

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Solar Power Class: Formulae Roundup

Okay, so back to the classroom, while it’s fresh on your mind. Yesterday we talked about Kirchoff’s Laws, as well as a few other formulas that you’ll use when trying to figure out your electrical generation setup and capacity. To review, here’s a listing of formulas:

Voltage = “Electromotive Force” = E
Current = “Amperes” = I
Resistance = “Ohms” Ω = R
Power = “Watts” = P

Ohm’s Law (for DC power): voltage = current * resistance ( E = I * R ),
power = current * voltage ( P = I * E )

Total Circuit Resistance: SERIES: Rt = R1 + R2 + … + Rn
PARALLEL: 1/Rt = 1/R1 + 1/R2 + … + 1/Rn

Voltage Divider Formula (Series): Erx = Et ( Rx / Rt ) (solve for resistor “x”)
Current Divider Formula (Parallel): Irx = It ( Rt / Rx ) (solve for resistor “x”)

Kirchoff’s Voltage Law (Series): Et – E1 – E2 – … – En = 0 (circuit w/ “n” resistors)
Kirchoff’s Current Law (Parallel): It – I1 – I2 – … – In = 0 (circuit w/ “n” resistors)

Whoa, boy, that’s a lot of formulas! Using these, you can pretty much figure out whatever you want about a simple series or parallel circuit. Of course, the circuits designed for power generation are rarely simple like the above, but we’ll get to that in a second!

So now that you’ve beat these formulas in your head, how do you use them? Here’s a sample problem:

“A 220V series circuit has three resistors. The first has a resistance of 25Ω, the second has a resistance of 50Ω, and the third has a resistance of 35Ω. What is the current and resistance of the circuit, and what is the voltage drop across each resistor? How much power will it produce?”

First, you diagram everything to see what you’re working with. You see that it’s a series circuit, which means that the current is common and the total resistance is the sum of all the partial resistances.

Rt = 25Ω + 50Ω + 35Ω = 110Ω

and since E = I * R, 220v = I * 110Ω, or I = 220/110 = 2 amps.

So now you know the voltage (220 V), the resistance (110 Ω), and the current (2 amps). To figure out the power produced, you simply use Ohm’s Law, (P = I * E), or P = 220 V * 2 amps = 440 watts. We’ll add that to the list: power (440 W).

The final part of the work is to figure out the voltage drops across the circuit at each resistor. This will require the voltage divider formula, since it’s a series circuit. ( Ex = Et ( Rx / Rt ) )

Here are the values plugged in for resistor 1: Er1 = 220V ( 25Ω / 110Ω ) = 50V.
Here are the values plugged in for resistor 2: Er2 = 220V ( 50Ω / 110Ω ) = 100V.
Here are the values plugged in for resistor 2: Er3 = 220V ( 35Ω / 110Ω ) = 70V.

You can check your work on this by adding all the voltage drops together: they should equal the voltage given in the problem: 50V + 100V + 70V = 220V. Good! Now for extra credit you can figure out the power produced at each resistor by using your power formula and the voltage and resistance of each resistor in the circuit. If you do, post your answer in the comments section!

This is basically the same process as for parallel circuits. Let’s use the same problem as above, but now the circuit is hooked up in parallel:

In this case, to get total resistance, you use the formula 1/Rt = 1/R1 + 1/R2 + 1/R3. This looks scarier than it is. to get a reciprocal (one divided by a number) on a calculator, you simply plug in the number, hit the divided by sign, then the equals sign. The calculator will do all the dirty work for you, but you should try doing them in your head sometimes, ’cause you never know when the calculator might stop working when you need to figure something out! So:

1/Rt = 1/25Ω + 1/50Ω + 1/35Ω = .04 + .02 + 0.0286 = 0.0886

This is the reciprocal of the total resistance (this is also called the “conductance”), so we take the reciprocal of this and get a total resistance: 11.287Ω. A total resistance of less than each of the parts? Yes, this example illustrates two things about parallel circuits: first, the numbers are rarely as “pretty” as in series circuits. Secondly, the total resistance of a parallel circuit is always less than the lowest partial resistance. If it’s not, then you calculated something incorrectly.

So now, as before, we know the voltage (220V) and the resistance (11.287Ω). To figure out the total current, we use Ohm’s Law ( E = I * R ): 220V = I * 11.287Ω so I = 19.49 amps. You can now easily figure out the power produced: P = 19.49A * 220V = 4287.8 watts of power (or 4.3 kW).

Using the same resistors and voltage, you’re generating more than ten times the power by hooking things up in parallel!

Rounding out the lesson, you’re now trying to figure out the current drop across the resistors (remember, in a parallel circuit, current is divided, not voltage). Use the Current Divider Formula: Irx = It ( Rt / Rx )

Here are the values plugged in for the first resistor: Ir1 = 19.49A ( 11.28Ω / 25Ω ) = 8.794 A.
Here are the values plugged in for the second resistor: Ir2 = 19.49A ( 11.28Ω / 50Ω ) = 4.397 A.
Here are the values plugged in for the third resistor: Ir3 = 19.49A ( 11.28Ω / 35Ω ) = 6.281 A.

To check your numbers, use Kirchoff’s Current Law, and add up the current drops:
8.794 A + 4.397 A + 6.281 A = 19.472 A, which is the same as above, save my rounding. This is why it’s important to keep numbers true to the highest number of decimal places you can… your work will be that much more accurate.

Again, if you want to figure out the power available at any point, use the same process as for the series circuit.

Congratulations! You’ve now mastered simple series and parallel circuits. That’s a lot to know. Next time, we’ll take a look at how to deal with more complex circuits, like the ones you might encounter in your alternative energy generating system, and also talk about why all this math is important to you when all you want to do is drop off the grid and tune out. I found that this stuff didn’t really cement in my head until I tried figuring out practical problems with them, so I’d recommend you do a little practice session, perhaps using the problems found at Open DNS: Ohm’s Law Practice 1, and Ohm’s Law Practice 2. Or try this site if you like to “play and learn”: Ohm’s Law Battleship Game, where your shots won’t land unless you can solve some problems along the way. See you next time, captain!

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