lifted from Sunfrost.com http://www.sunfrost.com/stand_alone_PV.html

Unfortunately, a 1 KW solar array sitting in direct sun for one hour will not produce 1 KWH of useable AC power. There are a number of ways energy is lost in this system. A major loss occurs because the panels produce their peak rated power at 17 Volts and most of the energy input into the battery occurs at a voltage closer to 13 volts. The energy is then taken out at about 12.4 Volts. The voltage mismatch alone results in a loss of over 25%. When analyzing battery powered PV systems, it is relatively easy to take these mismatches into consideration by using a current-based analysis. With this type of analysis voltage mismatches are automatically taken into account. To get a quantitative picture of the losses in a stand-alone system, let’s calculate the size array necessary to produce 1KWH with one hour of full sun. In a loss-less system, it would of course take a 1000-watt array to produce 1000 watts AC power. In a real system there will be a number of losses along the way. The input to the inverter will have to be about 1100 watts due to the inefficiency of the inverter. If this power is supplied at an average voltage of 12.4 Volts, then the batteries must supply 1100 watts/12.4 volts or 88.7 amps. For the inverter to produce 1 KWH the batteries must then supply or 88.7 amps for one hour or 88.7 amp hrs. (An amp hour is a unit of energy like a KWH). Assuming a 10% loss in the batteries the PV panels will have to supply an additional 10% more energy or 97.6 amp/hrs. To produce 1KWH with 1 hour of insolation will then require a 97.6 amp solar array. For each 17 watts of solar panels the panel will produce one amp; i.e., a 34-watt panel will produce 2 amps. The energy required to produce 1KWH of AC power with 1 hour of direct sun then be 17 watts/amp X 97.6 amps or 1659 watts which is a lot more than the 1000 watt array required in a loss less situation. These large losses make stand-alone power more expensive than a grid-tied system. In a grid-tied system the inverter loads the panels so that they are putting out their peak power. In addition, there are no battery losses and no backup system required during cloudy winter months.

from the Big Wiki: http://en.wikipedia.org/wiki/Solar_cells

excerpt: “A solar cell (or photovoltaic cell) is a semiconductor device that converts photons into electricity.”

http://en.wikipedia.org/wiki/Solar_cells#Simple_explanation

Each cell produces about .5 volt, and amperage depends on size. Many are stacked together to make a panel.

Animated (SWF) article about solar cells: http://www.energex.com.au/switched_on/activities/photovolatic/photovoltaic.html

AEZ Solar Cooking and Recipe Exchange

Solar Cooking Tips

From Jan on the AEZ list: Premade casserole type dishes like enchiladas, lasagna, shepherd’s pie, etc are particularly satisfying and effortless, except for the clean up. Baked potatoes/yams are also super easy. And I’ve seen premade (frozen) burritos. The all afternoon “stew” does require a little attention because a pesky wind can knock over your cooker or you will probably have to rotate your cooker to maximize heat. Not a big deal, just a consideration. For those of you who didn’t think to bring a solar cooker, think again, because you did! I have made nachos (pre-grated cheese is best and cleanest) in a car and once in Leslie’s tent – it was so darned hot in there.

For higher maintenance cooking like baking (brownies, corn bread, muffins and wedding cake), premix your dry ingredients into a zip lock bag large enough to hold both wet and dry ingredients. Label that bag with a list of the wet ingredients to add. To mix just add wet ingredients, zip it closed and mix with your hands on the outside of the bag. Now you can pour it into your greased pan. And, yes, your baking time will double in a solar “oven”.

Now about cleanliness. I’m not a freak about it, maybe it’s just a pet peeve, but I want to make a note about Tomato based sauces, ie. chili and spaghetti sauce. They are super hard to clean up after taking your already tortured grey water to a whole new disgusting level. When you make that type of dish for dinner watch your otherwise generous helper people disappear at clean up time.

From Cathe on the AEZ list: You can cook about anything. Just takes twice as long.

Mostly I just let it slow cook until I a read to eat. But I do watch greens and baked goods

Most pastas don’t do well in the solar oven unless you do not boil them in water first. Cook the in the pasta sauce. In the case of lasagna, butter the dry lasagna noodles with the cottage cheese or ricotta, then add the sauce.

A nice first dinner could be an organic chicken surrounded by carrots and potatoes. Put it in at 1 and slow cook it until dinner.

From Gonzo on the AEZ list: We tend to go super-SUPER simple on our solar cooking: cans or plastic packages of soup, stew, etc. from Trader Joes that we place on the roof or dashboard of our van in the morning. By lunchtime, they are hot and yummy. After lunch, we load up the car again for dinner! We usually eat out of the packaging to minimize clean-up and waste. Yum…all food tastes so good with playa dust for seasoning.

From Tony on the AEZ list: I have found things like lasagna, tamale pie, etc work real well. I pre layer then in cheap aluminum pans (think of the disposable kind only I reuse them) which I have spray painted black. Then I freeze them.

On the playa I take them out of the cooler. Let them thaw and then stick them in a solar oven to bake!

Cooking on the Solar Death Ray 3000

http://people.tribe.net/5969572e-afaf-4c36-97d4-b7be3d08f572
Use a universally useful clamp-together cooking device: pudgie pie, pie iron, toast-tite!
http://www.gleasoncamping.com/browseproducts/Round-Pudgy-Pie-Iron—Cast-Iron.html

They also come in square: http://www.pieiron.com/

Paint black with flat black high-heat barbecue paint for best results on the SDR3000!

Pie Iron Recipes! http://www.greatcamps.com/pie-iron-dinners-recipes-contest-7.htm

From Jan on the AEZ list: To cook fish, I’d probably wrap a thin wire to the end of a bamboo pole (like a fishing pole), attach a fishing hook to it and dangle a hooked cube or slice of fish to that. Then there would be no fishy toastite clean up to do.

Weiner on a Stick!

Fresnel Lens Cooker

From Ray-Bees on the AEZ list: I recently made a smaller version of the SDR3K using a Fresnel lens and found it very helpful to mount a pyramid of steel struts leading to a point somewhat behind the focal point. This makes it very easy to find the “hot spot” and stick your wiener in there. Wait, that didn’t come out right.

Jazzy Jeff’s Playa Ice Tea

A not-too-sweet refreshing beverage for those hot dusty days.

Bring 8 cups of water to a boil. Add 12 tea bags: black tea or whatever. Adjust tea bags to suit your taste! Let steep for several hours. Or place in fridge overnight. Remove tea bags and wring to get all the flavor out.

Add 1 cup of lemon juice: fresh or bottled
Add 1 cup of sugar: or to your taste
Add 8 cups of water or enough to make 1 gallon: stir well.

For the playa, pour ice tea into plastic jugs and freeze. NOTE: fill jugs only about 3/4 full as tea will expand as it freezes. Use the frozen jugs of tea as your ‘ice’ in your coolers. When it thaws, it’s delicious and ready to drink.

**Mr. Wagon’s Playa Salad**

Japanese Salad:

1 head cabbage shredded
4 green onions chopped
4 T. sesame seeds toasted
4 T. sliced almonds toasted
2 pkg Top Ramen noodles

Mix first 4 ingredients. 1/2 hour before serving break noodles into the cabbage mixture, add the dressing and toss well.

Dressing:

4 T. sugar
1/2 c. sesame oil
1 t. pepper
6 T. rice vinegar
1/2 c salad oil
salt to taste (optional)
seasoning packets from Top Ramen noodles

Mix and shake.

Hemp Nut Health Smoothie

Anti-Cholesterol Diet Approved!!

6 Oz COLD Soy Milk [Vanilla flavor is good!]
55 grams frozen OJ concentrate [~1/10 of a 16Oz can]
8 Oz container fat-free Yogurt [Vanilla flavor is good!]
1/2 Cup/67g Oat Bran [yes, Oat Bran– as in Quaker!] (frozen)
1/4 Cup/33g Hemp Nut [Cannabis Sativa L.] (frozen)
1 frozen banana [sliced up to save your blender]
~200g frozen strawberries

Put the liquids, Oat Bran and Hemp Nut in blender, along with the sliced up frozen banana. Run at low to moderate speed until uniformly mixed, then start adding strawberries, and increasing the blender power as required until all fruit is added and the mixture resembles the thickest milkshake you’ve ever tasted.

Try organic blueberries, mixt berries, peaches, key lime yogurt– variety!

(My K-Tec blender odometer reads 763 this AM!)

SOLAR DEATH RAY 3000

Solar cooking with the power of a BILLION suns

You bring it. You cook it. You eat it.

Eye protection and a new clean skewer provided. Please bus all cookware to your cleaning facility

Sorry, closed at night

http://people.tribe.net/5969572e-afaf-4c36-97d4-b7be3d08f572

Solar Power for a Burning Man Camp

This is a short, technobabble-lite description of how I designed, purchased, assembled, and utilized a solar photovoltaic system to power a Burning Man camp. This article will tell you most, but not all, of what you need to know to use solar electric power at your own encampment (whether it be at Burning Man or elsewhere). I hope you enjoy this information. Please feel free to contact me with any corrections or suggestions at jason(at)coopersco(dot)com

Design: Basically, you need to figure out how much power you will use, how much you will bring with you (in the form of charged batteries), and how much you will need to generate. My system powered a small water pump (for the Mist Tree pictured with the author here), some Christmas tree lights, a car stereo, and some other lightly used devices. All of the devices I used were 12v, so calculating usage was pretty easy; I multiplied the number of amps the device consumed by 12 (the voltage) and to get the watts used, then multiplied by the number of hours the device would be used to get the watt-hours. I added up all my watt-hours to get the total amount of power I planned to use. (The basic equation that you use in many electrical calculations is amps = watts / volts. You can rearrange this equation to suit your needs, like amps * volts = watts or volts = watts / amps).

Some of you will want to power 120vac devices like you plug into your home outlets. To do so you will need an inverter; this device converts the 12v direct current supplied by batteries into 120v alternating current. I bought a cheap one at Fry’s and it worked well for my needs (charging power tool and AA batteries, powering a stereo receiver/amp).

Next I calculated how much power I would bring in the form of two heavy-duty 6v lead acid golf cart batteries. Each held 360 amp-hours at 6v, for a total of 360 amp-hours at 12v, which we can convert to 4320 watt-hours using our handy equation above (360 * 12 = 4320). In the previous step I calculated I would consume a total of about 6,000 watt-hours during my stay at Burning Man, thus requiring that I generate about 2000 watt-hours (6,000 – 4,320 = 1680).

I selected 6v golf cart batteries because they are much more tolerant of deep discharge cycles than normal car batteries. However, car batteries will work just fine for the short periods that most of us use our solar systems, so if you’ve already got a car battery or two you can use those instead.

To generate this power I used a 120 watt solar panel made by Astroworks. I connected it to the batteries with a charge controller, which also provided me with a panel output meter (so I could see how much of the rated 7 amps the panels were actually generating), a battery charge level meter (so I could see how much juice I had left in the batteries), and short circuit protection (which disconnected everything if anything went wrong). You don’t strictly need a charge controller, but I’d highly recommend one for all but the most simple systems.

The panels were rated to output 7 amps at 12vdc in full sun. I figured that I could keep the panels in full sun for about 5 hours a day, thus generating 420 watt-hours each day (7 * 12 * 5 = 420). I needed to generate about 2000 watt-hours, which meant I’d have to keep the panels in the sun for about 5 days.

As Burning Man progressed, I realized that while I was generating about as much power as I had anticipated, I was using more than planned. I had to connect my batteries to a generator (via a 12v charger normally used to charge car batteries) a couple times. This use of fossil fuels in an alternative energy system was unfortunate, but bringing a 12v charger does provide you with an easy and effective back-up to under-generation/over-consumption during your stay in the desert. A little red wagon was also very useful for moving the heavy batteries to the generator and back.

Hopefully this is enough information to get you started with your alternative energy system. I am far from an expert on this subject so please let me know if I’ve made any major errors!

Thanks for reading!

Jason