Posts tagged solar

Photovoltaic Class

To all my fellow travelers on the road to solar living! If you’re following along with the solar power class, be sure to note that the class now has its own page on the site (it’s at the top of the page on the right-hand side), where you can find all the lessons in one easy to remember place. If you are following along, stop by and say hello to your other classmates by commenting on that page, so we can facilitate discussion and learning for all involved. Also, if you find great resources that everyone will want to know about, post them there!

For my fellow Los Angeles classmates who are checking in, though all the information now posted is publicly available to all who visit the site, there will eventually some information and resources posted which are specific to our class that will be available only via password. By commenting and saying hello, I will know your email address to send you a password when such information is posted.

See you there!

Advertisements

Leave a comment »

Solar Power Class: Kirchoff’s Laws

Whew! It’s been a busy couple of weeks in my photo-voltaic class. I was starting to fear that I’d have to take a math class to keep up with all the formulas! When I posted the first week’s lesson, I realized later that I’d given out misinformation, which is the danger of posting about something you don’t yet understand! So, from this point out, I’ll just post the lessons after I’ve been tested in the contents, that way you’re always getting the information someone has TOLD me I understand. Since we had a test this past weekend, here’s a new dose of mathematical fun!

This week: Kirchoff’s Laws. Last time, I discussed Ohm’s Law of DC power, which interrelated voltage, current, amperage, and power, and provided several formulas you can use to figure out any of the above for a circuit. If you’d like to review, check out the original post here. Now, let me repeat a few pertinent facts: a series circuit is when you basically hook everything up in a big loop, positive end to negative end in a chain. See the diagram below:

A parallel circuit is one in which the positive and negative ends are “shunted” together (parallel circuits are sometimes called shunts) creating a ladder effect. Again, see the diagram below:

Series circuits are called voltage divider circuits, because though a common current flows across the wire, at each stop along the way, voltage is dropped. These are two important concepts: 1. current is common. 2. voltage is divided along the circuit. Parallel circuits are the opposite. Though a common voltage flows through all the wires, the current is divided between the different potential paths. Therefore, in a parallel circuit, 1. voltage is common, and 2. current is divided along the circuit. Series circuits are called “voltage dividers” and parallel circuits are called “current dividers”. VERY IMPORTANT is you want to know how to manipulate these circuits later on.

There are even two formulae which will help you to calculate a voltage or current at any particular point along a circuit. Say you have three resistors along your circuit. In a series circuit, a voltage divider, if you want to know the voltage of resistor “b”, you would use the voltage divider formula: Erb = Et (Rb/Rt), where t represents total and Er is the voltage drop. Here’s an example:

In a series circuit with a total resistance of 100 Ohms, and a voltage of 120V, resistor b has a resistance of 25 Ohms. The total voltage drop across resistor b would be:

Erb = 120 v ( 25 Ohms / 100 Ohms ) = 30 V

Now, if you aren’t sure what the resistance of a particular resistor on the circuit is, then Kirchoff’s Law of Voltage (for series circuits only!) comes into play. His law states that the total voltage minus the voltage of each resistor, etc on the circuit will always equal zero. In other words, the Total Voltage equals the sums of all the voltage drops along the path. Here’s the official equation: Et – E1 – E2 – … – En = 0, where the circuit has n resistors. So if you know that one resistor has a voltage drop of 25 v and the third has a voltage drop of 50 v, and the total voltage is 130 v, then 130 – 25 – E2 – 50 = 0, and E2 = 55 v. Got it?

Now, on to parallel circuits, ones you’ll see a lot of in battery configurations. Because parallel circuits are current dividers, they need a separate formula for figuring out current drops around the circuit. This is called the Current Divider Formula (using Current at Resistor b): Ib = It ( Rt / Rb ). As with the voltages of a series circuit, if you need to know the current drop at a particular point, Kirchoff had a law for that, too. It’s called Kirchoff’s Current Law (for parallel circuits), and it states that the total current minus the current drops along the way, equals zero. So It – I1 – I2 – … – In = 0, where the circuit has n resistors.

Now, this is a LOT of information to absorb, especially in practice, so let me stop here for now, and we’ll pick up here tomorrow with the rest of the lesson. It seems like way too formulas to ever be useful, but once you get to solving practical equations with them, it’s not too bad. But let’s save that for the next lesson, sleep on it, and I’ll see you in class tomorrow~

Comments (2) »

Link: “How I built my Solar Panel”

How I built my solar panel

The link above demonstrates a nice DIY version of a solar array, using damaged solar modules that can be bought at low price on eBay. This resourceful astronomer also built himself a DIY wind turbine, so if you’re considering doing either, this is worth a look.

This panel was designed to work in sunny Arizona (a beautiful state!), which is a perfect place for setting up an array, especially given the large number of off-grid properties there which would be prohibitively expensive to wire up to the utility power company.

He includes lots of good tips about what to look for when buying your solar panel modules to string together into the final product, so you can learn from his mistakes, and also know a bit more about what is actually important to the functioning of the modules. Above is a picture of the finished box containing the panel. Good luck with construction!

Comments (4) »

Cooking: Refining the Recipes

Here’s a few pics of my “new and improved” Banana Pie, now featuring Ginger and mixed berries. By eliminating the extra juice and adding fruits that I foraged and some shredded ginger, I was able to both increase the sliceability of the pie and add a crucial taste dimension. It kept very well covered at room temperature for a day. If I had a fridge, I’m sure it would have kept longer and tasted good chilled.

Yum. This was a drastic improvement over the past recipe, though both were tasty. This time, I added: 1/2 ginger root, shredded; 10 blackberries; 3 ripe bananas, mashed; 2 passion fruits (foraged); flax seeds (enough to coat top of pie); and graham cereal to top (a nice thick coat, added after cooking, to cover the browning of the bananas). Cook covered for 1 hour. Make sure you shred the ginger very fine, and mix well or spread evenly, unless you like your desserts “spicy”.

Crab and Artichoke Frittata. Next, I attacked the egg “jello” recipe, hoping to solve a little of the texture problem. This time, I used: three eggs, lightly beaten, but not totally homogenized; 1 small can crab meat; 1/2 can quartered artichoke hearts (not the marinated kind, the kind packed in water); two pinches crushed sea salt. Cook covered for 1 and 1/2 hours. The result? The eggs did have a slightly better texture, but I’m thinking that the texture is something iherent in the solar cooking process. The color issue did not improve (eggs turn brown in the solar cooker), but the result tasted good, especially when an additional pinch of sea salt was sprinkled on top before serving. No pictures here, as it wasn’t too photogenic, but it was a solid meal, and my cats went nuts for it, (and ended up eating a few human sized portions of it while I wasn’t looking!)

For a hearty side dish, I prepared carrot and black eyed pea succotash. Very simple, few ingredients, and tasted and smalled great. It was so easy I almost feel guilty calling it a recipe. I used: 1 can sliced carrots; 1 can black eyed peas; 1 t sea salt; 1 T sesame seeds. Mix all, and cook covered for 45 minutes, or until hot. Here’s the (predictable) result, which needed no extra seasoning to be palatable:

So there you have it: three “new” recipes for summer cooking fun. As I learn more about urban foraging (more about this in my next post) I am trying to incorporate locally found foods into my recipes. We’ll see how it goes.

Comments (1) »

Solar Panel Installation (and Eating Your Neighbor’s Lawn)

Great news!  It’s been a while since I posted, but there are a slew of recipes that you’ll be seeing added over the next few days.  As few things in life turn out perfectly the first time, I have been refining the previous recipes and trying a few new ones, side dishes mostly.  Most have been successful, but more on that later.  Great news, you ask?  Yes!  I’ve just signed up to get certified as a solar panel installer.  This means that for the next eight months, I’ll be working toward completing the necessary coursework and study hours for the National certification exam, and hopefully getting some practical experience working with panels along the way.  You might be asking why this should interest you in any way… well, since I love to share, and since writing about things helps me to learn, I mean really LEARN things, I’ll be keeping a sort of study diary on this site.  So if you’re wondering where to start on that whole “watts vs. volts” issue, or if you need a little brush up on your high school physics or electronics (and who doesn’t?), keep checking back often to see if I’ve covered the topic here.  I’ll be using the SEI’s textbook on photovoltaic installation and repair, which is pretty much the best on out there as far as I can tell.  Class starts Wednesday, so more about that then!

In the meantime, I’ve been reading a lot about urban foraging.  It’s a huge topic with relatively few available references.   But starting with Christopher Nyerges’ excellent Wild Foods and Useful Plants guides and also covering specific guides to my local SoCal area, I’ve been out every morning hunting for food.  And it’s everywhere!  Did you know that most of the plants in your garden, never mind those that professional landscapers use in public places, are edible in one way or another?  Geraniums, pansies, daylilies, lavender, nasturtium, chrysanthemums, marigolds, roses and more all make tasty snacks alone or blended into recipes.  You can even replace some of the gourmet items in your pantry with wild alternatives, adding an exotic flair to your cooking.  For example, nasturtium seeds make an excellent caper substitute when pickled, and you can make jellies straight from your yard instead of store-bought marmalades. 

If you’d like to find out more about the plants of your area, I’d highly recommend you check out a book that specializes in your area and start looking for wild foods every time you go out the front door.  I have to admit that though I’d never even noticed what was edible before, now I’m finding myself distracted trying to walk down any street, looking at the possibilities.  And the fruit you pick is SO much sweeter than the one you buy, even if just in principle.  The book I just finished Edible and Useful Plants of California (can’t remember off-hand who wrote it) also included many great anecdotes about the Native American food and medicinal uses of various plants.  When moving away from reliance on the grid, you’d do well to know a bit about the native flora of your community.  And I hardly need to spell out its importance after grid-crash, except to point out that it will be the few months following immediate aid and before people’s sowed crops mature that will be hardest for individuals to survive.  If you know about edible plants, then you can sit happily munching on your neighbors’ lawns while they sit inside their houses panicking.  You might even get an “I told you so” out between bites.  How’s that for sweet justice!  Until next time, happy foraging!

Comments (4) »

Solar Cooking Roundup: Two New Recipes

As mentioned previously, I haven’t been getting out the oven as often lately, as it’s been unseasonably cool and cloudy here. But, as if magically anticipating that summer was right around the corner, a few days back the thermometer jumped about 30 degrees. Yikes, it is triple digit hot!

So, of course the first thing I did was pull out the box cooker. After a yum but “haven’t I tried this before?” few meals of roasted red sweet peppers with cheese, it was time to do a little culinary exploration. So this past weekend, I fired up the “grill” and made two new recipes.

First up:

Banana Nectarine “Pie”

3 bananas, roughly broken into slices
1 nectarine, chopped
2 T flax seeds (for nutrients and “crunch”)
1/8 cup Sunny Delight (next time I’ll skip this)
1/4 cup honey graham cereal

To make, mix all ingredients except graham cereal into pan. Cover and bake for 30 minutes, or until the bananas smell super sweet and mash easily. The flax seeds will swell to a larger size, too, so you know they will not be too hard. Bring out of the sun and mash the bananas with a fork, stirring to mix everything well. Allow to thicken for about ten minutes. During that time, crumble graham cereal into the bottom of ramekins/ cups and crumble more for the tops. Spoon mix into each cup and top with more crumbled graham cereal.

This recipe turned out well taste-wise. Next time I might skip the Sunny D (there was a lot of natural liquid in the mix after cooking) and add a little cinnamon before cooking, but it was also good as is. The only disconcerting part was that the bananas looked kind of brown in the pot, but covering the top with graham solved that aesthetic dilemma. Easily makes enough for two people.

Today, I tried a different take on my pepper lunch:

Chili and Celery with Mango

2 large green Anaheim Chili peppers
2 long stalks celery
1 sweet red pepper
Annie’s Naturals Organic Balsamic Vinaigrette Marinade
1 large mango

To make, cut and deseed the chilis and sweet pepper into pinky finger size strips, and chop the two stalks of celery. Pour a little marinade over the mixed veggies in the pan, and put in the sun for about an hour. At that point, I checked the progress, added a bit more marinade, gave everything a good shake to cover, and returned the pan to the oven for another 1/2 hour. Bring everything inside, add the mango (chopped) to the mix and stir together. Serve immediately.

Yum. Of all the dishes I’ve made so far, this was my favorite. At first, I was nervous about adding the mango to what smelled like a very hearty mix, but it worked perfectly, giving everything a cool taste even on this scorcher of a day. And it needed no seasoning either, though I’d imagine it would be good with a sprinkle of coarse sea salt sprinkled on top. This recipe will make it into the cookbook. Makes enough to feed one VERY well, or two for a light lunch or appetizer.

And here’s the finished result:


Now for a nap to work off all that gourmet eating! =)

Leave a comment »

BOOK REVIEW: the Self Sufficiency Handbook

The Self-Sufficiency Handbook: A Complete Guide to Greener Living by Alan and Gill Bridgewater

the Self-Sufficiency Handbook

The title of this book is perfect. There are no crazy survival tips here, although I wouldn’t mind having this book along in a pinch. It’s a guide for getting your existing house off the grid, and also for evaluating properties in terms of their sustainability potential. The writers live in the UK, after years stateside, so the companies and tips are both oriented toward those countries. But there is a nice discussion of navigating local laws no matter where you decide to drop your hoe and start gardening.

After a nice discussion of housing, which includes talks about insulation, orientation, ambient heating/cooling, alternative energy sources, and materials, they move on to daily living practicalities. First, getting light. That done, next you need food. This is where the book really shines. There is an in-depth lesson on growing an organic garden, including successful composting and which crops should be planted where and when, what needs rotation (and a sample rotation schedule that will leave you with fresh foods year-round) and what can stay put, and the care profiles for a large variety of different garden plants. They are careful to share wisdom on how much land you need to make your off-grid dreams happen, and also on how to choose property that will lead you to success.

Animal husbandry is covered in detail species by species, along with construction considerations, possible worries and probable successes of owning each type. The sections are not overly in-depth – I thought they were perfect for the off-grid enthusiast with lots of commitment but no experience with husbandry. Of course, one can never emphasize enough the time it will take to properly care for animal on your own property. They cover it nicely, if briefly, by saying this: if you own animals, you will have to feed them EVERY DAY, holiday or not. Yes, that’s EVERY day. Having kept horses growing up, I can relate to the urgency with which they repeat this statement throughout the book. Take heart.

The last section of the book can best be described as a tutorial section of recipes for survival. Not pemmican or Gorp-style recipes, but rather old-fashioned recipes for things like candles, making soap, making chutneys and jams, and brewing beer and making wine. Their recipes are pretty short and look easy to handle. In fact, the whole book was particularly well planned to fit each concept on two facing pages, so you’re never left looking for information in a thick chapter of words. I’m sure this limits the amount of information that can be presented a little, but I didn’t notice.

If you’re even considering moving off-grid, or even just converting a section of your yard to an edible garden, you should pick up this book. It’s fairly new, but with its special emphasis on looking at your actions in terms of an overall lifestyle, I think it will one day be considered a standard text in self-sufficiency. Which, as gas rises toward the $5 mark, is something we could all afford to learn more about.

Comments (2) »

%d bloggers like this: