Water and Power

Our Rocket Stove

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Preparedness, Rocket Stove
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  • Editor’s note: we have a new design for a portable rocket stove here.

Low-tech is the new high-tech, and the best example of the low-tech revolution is the miraculous rocket stove–a stove that makes it possible to cook with small twigs–no logs needed! Best of all rocket stoves are easy to build. We liked the idea so much that we decided to build a permanent one just off our back deck for entertaining and as a backup to our gas stove should an emergency take out our utilities.

The rocket stove was developed for use in poor nations where wood used for cooking has led to the vast, wholesale, deforestation of large swaths of the earth’s surface. Rocket stoves can be built out of metal or masonry and consist of a L shaped tube, at the bottom of which you place your wood. The chimney effect creates a highly efficient, largely smoke-free burn. There’s no need to cut down a tree to cook your dinner–all you need is a few small branches or twigs.

Before we built the rocket stove we considered making a cob oven, a mud domed wood fired oven in which you can cook bread and pizza. There’s a trend in the eco-world to build cob ovens and we felt a certain pressure to keep up with the eco-Joneses. We started to build the base for one and then began to think about how often we would actually build a fire, especially considering that it has to burn for several hours before a cob oven gets hot enough to cook in. Also, where would we get the logs? And how good is it to burn such a fire and contribute to Los Angeles’ already smog choked air?

Staring at the bricks we had scavenged to build the base of cob oven, we realized that we could re-purpose them for a permanent backyard rocket stove that we would actually use. Furthermore we realized that our rocket stove could burn some of the palm fronds that regularly tumble down from the iconic palm trees that line our old L.A. street.

Here’s the materials we used:

36 bricks
4-inch galvanized steel stove pipe elbow
4-inch stove pipe
ash (scavenged from park BBQs)
1 tin can
50 pound bag of premixed concrete for the base
mortar mix
grill (scavenged)

The first step was to make a small foundation for the rocket stove. We fashioned a 18 by 18-inch by 4-inch slab with 2 x 4 lumber and a bag of premixed cement. Folks in cold places will need to make a deeper foundation to avoid frost heave.

Next we built a brick cube, leaving a small hole for the bottom of the stovepipe. For advice on how to build with brick we recommend taking a look at this. As you can see our masonry could use some more practice, but the results are not too bad–we like to think of our stove as being a bit “rustic”. You can avoid the hassle of brickwork by making a simpler rocket stove–check out these two instructional videos, one for a metal model, and another version using bricks. We chose brick largely for aesthetic reasons and we’re satisfied with the results.

Drawing from Capturing Heat

The next step is to put the pipe together fitting the elbow up into the longer pipe, and sized so that the top of the pipe is just below the bottom of the grill. Check out our earlier post for a video that can help with this part of the assembly. Serendipitously, on a bike ride, we found a grill in the middle of Sunset Boulevard that fit the opening in our brick rocket stove exactly.

You pour the ash into the completed brick cube to fill the space between the pipe and the inside wall. The ash acts as insulation to increase the efficiency of the stove. You could also use vermiculite but note that sand or soil will not work. Insulation works because of small pockets of air between particles, hence the need for ash or vermiculite, which are also non-combustible. We used a piece of scrap sheet metal with a 4-inch circular hole cut in it to keep the ash from spilling out the gap between the pipe and the squarish opening at the bottom.

Lastly you use a tin can sliced down the side and flattened out to form a shelf which you insert into the elbow at the bottom of the stove. Note the drawing above for the shape of the shelf. You put your twigs and kindling on this shelf and start the stove up with newspaper underneath the shelf. As the twigs burn you push them in over the edge to keep the fire going.

Our first test run of the stove was very successful–we boiled a pot of water and cooked some eggs in a a pan. The fire burned cleanly with little smoke except during start up. For more info on rocket stoves check out the Aprovecho Research Center.

And please people don’t burn wood inside and watch out for embers. Make sure you put the fire out completely when you are done cooking!

Plantain!

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Food, Foraging, Gardening, Water and Power, Water Conservation

Homegrown Revolution neighbors Annelise and Eric intercepted us on our nightly dog walk and not only invited us up to their front porch for a glass of wine, but also sent us away with a couple of plantains harvested from their next door neighbor’s tree. It’s exactly what we’d like to see more of–folks growing food instead of lawns and everyone sharing the abundance.

While there’s a lot of banana trees in Los Angeles they tend not to yield edible fruit since our climate is not quite hot and humid enough. But plantains, judging from the delicious taste of the ones we fried up, are a different story. They do require a lot of water to grow, but greywater expert Art Ludwig calls bananas (the same family as plantain) “the premiere plant for greywater in warm climates”. You can bet that as soon as the building inspectors sign off and leave the scene of our newly retrofitted foundation at our crumbling 1920s vintage compound we’re going to try to figure out a way to route the shower drain out to a new mini-grove of plantain.

We’ll be our own banana republic and do the world a favor considering the amount of blood that has been spilled bringing bananas to North America. Witness Chiquita’s recent admission to teaming up with right wing terrorist groups in Columbia.

In the meantime, for the Homegrown Revolution readers out there in warm climates here’s the lowdown on growing bananas and plantain.

Rainwater Harvesting for Drylands

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rainwater harvesting

“The bricoleur, says Levi-Strauss, is someone who uses “the means at hand,” that is, the instruments he finds at his disposition around him, those which are already there, which had not been especially conceived with an eye to the operation for which they are to be used and to which one tries by trial and error to adapt them, not hesitating to change them whenever it appears necessary, or to try several of them at once, even if their form and their origin are heterogeneous.”

-Jacques Derrida

Homegrown Revolution loves cheap low-tech solutions (not to mention pretentious quotes), which is why we especially like “bricoleur” and Tucson rainwater harvesting guru Brad Lancaster and his ongoing book series Rainwater Harvesting for Drylands. Volume one is already out and volume two is due out this summer. Landcaster’s ingenious methods involve little more than careful observation and some work with a shovel. He suggests that harvesting rainwater begins with considering the flow of water from the highest point (which for most people will be the roof) to the lowest point in your yard and then simply figuring out simple ways to get that water to percolate into the ground to nourish your plants.

We’re especially fond of his method of hijacking street gutter runoff and directing it with a small improvised check dam into a dug out basin in the parkway. We’ve watched our neighbor’s lawn watering runoff for years and wondered if we could find a way to use that water. You can watch two videos showing Lancaster at work here. And a podcast here.

Flexible PVC Pipe for Greywater

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Water Conservation
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Following up on an earlier post about using your washing machine’s greywater in your garden we thought we would revisit the sexy and exciting world of flexible 1″ pvc pipe and other exotic plumbing materials to be found in the isles of your local pool and spa supply shop–the unlikely go-to source for greywater revolutionaries. Flexible pvc pipe is probably the easiest way to run washing machine waste water out to your plants, just like you would with a garden hose. But garden hose could burn out your washing machine’s motor because it’s too small and has a tendency to kink up, hence the need for flexible 1″ pvc.

Another handy item from the bourgeois land of pools and spas is the swing check valve which will keep waste water from flowing back into the machine and gunking up your clean clothes. We hope graphic designers will appreciate (or perhaps not) those glowing blue drop shadows, but we digress. Apparently, this back-flow problem is not an issue with all washing machines so we’d hold off on getting one of these slightly expensive things until you know it’s an issue.

We’ve already discussed the not-safe-for work-sounding “three way diverter valve” which seems like something this business located in our neighborhood might carry (NSFW!). The tree way diverter valve, you may recall, is a way to send that greywater temporarily back to the sewer should the need arise. Another, much cheaper way to divert grewater is with a duo of two way valves. The radical Greywater Guerrillas of Oak-town show you how to do this on their fantastic website (which seems temporarily to be under construction–check back later).

So when the inevitable zombie hordes cause chaos across the land, just remember that you can scavenge hot tub parts in their wake to run your greywater system.

A Bicycle Powered Washing Machine

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Bikes, Water Conservation

Homeless Dave’s Bike Powered Washing Machine

Of all the potential bicycle powered applications, other than the primary one of simply gettin’ around, washing machines seem the most practical to us. With the bike powered wash cycle, someday spin class and laundromats could co-locate. In the meantime, if you’ve got the space, a BPWM can also water your garden while giving you a chance to loose a few pounds.

There are a couple of designs floating around the internets, but we like Homeless Dave’s the best because it you don’t need to do any welding or fabrication of special parts. Homeless Dave’s extensive instructions require scavenging a bike, a trainer (we found one in the street, but we’ve also seen them at garage sales and thrift stores), and a top loading machine.

Homeless Dave’s design only does the spin cycle, not the washing, so it will be up to Homegrown Revolution to come up with a design for a full-on bike powered washing machine (we’ll wait for our hated Sears model to die first). When that day comes we’ll post the design and a special soak and spin music mix.