StoveTec’s Hot Rocket Stoves

StoveTec’s wood burning rocket stove on the left, charcoal and wood on the right.

A reader comment alerted me to a very cool product, the StoveTec Rocket Stove, offered by the “not-just-for-profit” wing of the Aprovecho Research Center. Profits from sales of the stoves benefit the Center’s research. StoveTec sells two rocket stoves, one for wood and the other for both wood and charcoal. While I haven’t tested one, the $37 to $40 price is a bargain.

Rocket stoves are a simple “appropriate” technology that burns small pieces of wood and charcoal efficiently. We’ve blogged about them before and even constructed our own out of a vent pipe and bricks. Instead of burning a log to cook you can use trimmings from trees, bushes and even agricultural waste. According to StoveTec,

“StoveTec Stoves, rocket stoves invented by Dr. Larry Winiarski, use 40-50% less fuel and reduce emissions by 40-75% while reducing green house gas (GHG) emissions an estimated 60% or 1-2 tons per year. These stoves are preferred over other improved cook stove and three stone fires by 95% of users in Uganda. High adoption and preference reported in India, South Africa, Ethiopia and Chile proves the stoves great versatility among many different users.”

Looks like they could find a nice home in North American as well. Do some pruning and then cook dinner. How about a rocket stove tailgate party?

Going Gray!



Got a nice note and some pics from Ben in Portland:

“I bought your book and it has become my mission manual. We own a house in Portland, OR, and I just today did my first project out of the book – routing the shower drain into the garden. It cost about $60 for all the pipe, glue, a 2″ hole saw to drill through the wall, and a new drain kit (my old drain was decroded as crap). Our house is only 750 sq. ft. (plenty for me, my gf, and our 3 dogs), and luckily our bathroom is right next to the garden plot I’ve had for about 3 years now. We’ve got a ton of squash going, which as you know takes a good bit of water, so I thought our not-so-gray shower water would be much appreciated by the little yellow bastards. Another benefit is that we won’t have to deal with the recurring shower clogs which have been forcing us to use drano.

The drain setup was super simple from a plumbing perspective, so all I did was cut off the old drainpipe, replace the drain assembly, and route a new pipe out to the garden. It took three 22 degree couplers, one 4 foot and one 10 foot section of pipe. the pictures sort of show what the finished piping looks like. I know it looks like I had to rip through the floor to get to the drain, but that’s just because whoever installed our shower years ago did a terrible job.

I drilled holes every 6 inches or so in the pipe that goes out into the garden. I may need to cover them with mesh (I’d appreciate your advice here) and dig some trenches to route the water into the rest of the garden, but for now it’s working great!

Thanks for your wonderful book and website. I will send you more pictures as i do more projects!

-Ben”

California’s New Greywater Code: Common Sense Legalized!

On the left is our yard which is irrigated by the washing machine. On the right, the neighbor’s yard which is never watered.

This Tuesday the California Building Standards Commission legalized our formally outlaw greywater system. For several years now, we’ve sent our washing machine waste water out to fruit trees in the front yard. The new regulations are a rare common sense moment for our otherwise troubled state government. Let’s hope our current hard times spur more innovation like this. Originally slated to go into effect in 2010, the plumbing code was updated as an emergency measure to deal with drought conditions that have plagued the southwestern US for years. Under the new California greywater code:

1. In most cases you won’t need a permit.

2. Allows discharge into a simple mulch basin rather than the expensive and complicated sub-surface emitters required under the old regulations.

3. No exspensive pumps or filters required!

Here’s the new code as amended (pdf).

Unfortunately the code can be superseded by local municipalities. Plumbers unions opposed loosening the code, no doubt fearing the loss of business. Combined with NIMBYs, they could put pressure on city governments to keep greywater illegal. It’s time for us Californians to be vigilant and start letter campaigns should cities try to restrict our new right to use our greywater.

As for the practical side of this new law, I’d suggest that anyone interested in installing a greywater system keep it simple and low cost. I can’t think of any better resource than Art Ludwig’s book The New Create an Oasis with Greywater: Choosing, Building and Using Greywater Systems and his website oasisdesign.net. Take note of Ludwig’s free open-source laundry to landscape plan.

And don’t forget, Homegrown Evolution is offering a DIY Greywater class on Sunday August 16th at 11 a.m. in Silver Lake (Los Angeles). Sign up here.

The Great Greywater Debate- PVC or Polyethylene?

PVC v. Polyethylene

Homegrown Neighbor here. I’ve been wanting a greywater system for a long time. My old house does not exactly make access to the pipes easy, so I’m starting with just the washing machine. The neighbor, Mr. Homegrown, is anxious to try out a new design from Oasis.

So we have been trying to get all the pieces and get it done- and here is where we get stuck. The system can either use polyethylene tubing or pvc. PVC is ubiquitous, cheap and toxic. Just how toxic, I don’t know exactly, but I’ve never chewed on any pieces just to be on the safe side. PVC is toxic to manufacture as well. This makes polyethylene the more ecological approach. But it is very hard to find in the size we need for the greywater system. And you have to buy a minimum amount- about 250 feet is the smallest we have found so far. For my yard, we probably only need about 40 feet. Plus, you have to mail order it. If we go the pvc route, it would cost far less and we could buy all the pieces at the local hardware store. We also want the system to be replicable so that we can share it with others and encourage them to use greywater. Searching for the parts for the polyethylene version is confusing – pvc is easy and accessible. This is the challenge. So what do people think- should we go with pvc or polyethylene?

Mr. Homegrown here. So I just found a local source for 1-inch polyethylene: Aqua-Flo. Cost is in the neighborhood of 33¢ a foot depending on how much you get. It comes in 20 foot and 100 foot lengths. So I think we’re gonna go with polyethylene. Incidentally, when I called Aqua-Flo they asked if I was going to make hula hoops.


A correction and update 7/25/09: The Aqua-Flo branch I went to does not have black 1-inch HDPE tubing in stock. Other branches have it, but only in 500 foot rolls that cost over $300. A roll that long would make sense for a contractor, but for DIY greywater installations it ain’t practical. Aqua-Flo does carry a new HDPE product called Blu-lock. You can get 1-inch Blu-lock in-100 foot rolls for a reasonable price (more info to follow in another post). Blu-lock uses special proprietary fittings that are easier to assemble than conventional mainline drip tubing and, intriguingly, allow for disassembly. I’m going to test Blu-lock and will report back on the results.

Washing Machine Greywater Resources

Pantyhose filter

For those of you attending our Wednesday night greywater workshop at Good and for those of you who can’t, here’s a list of resources for using your washing machine as a irrigation source:

The New Create an Oasis with Greywater: Choosing, Building and Using Greywater Systemsby Art Ludwig. This is the bible of greywater. Follow Ludwig’s instructions and you can’t go wrong. Buy a copy via the link, and you’ll help support Homegrown Evolution.

Ludwig’s open source Laundry to Landscape system.

1″ polyethylene tubing–an alternative to PVC pipe.

Oasis Biocompatible detergent, the only laundry detergent we can find that’s appropriate for greywater use. It works great and, again, click through the link and we get a little support.

A selection of three way diverter valves. Note the 1″ brass model for laundry systems. Use these diverters to shift between sending your greywater outside or back to the sewer. Great if you have to do a load of diapers. We don’t have one, but we’re both cheap and kinda extreme.

A local Los Angeles source for drums, the Apex Drum Company: www.apexdrum.com. Phone number: (323) 721-8994. Located at 6226 Ferguson Drive in the picturesque city of Commerce. You can also scavange drums, but make sure they didn’t have nasty chemicals in them. See our greywater surge tank post for what kind of barrel we like to use. Note that you can also turn a surge tank into a rain barrel.

A description of our greywater fruit mini-orchard.

Our greywater surge tank version 1.0. We’ve since added a pantyhose filter as seen above to catch lint that can clog the tank and garden hose. It’s just some threaded ABS waste pipe fittings screwed together with used pantyhose.

A liquid fertilizer of the type that you could add to your greywater surge tank during a wash cycle to fertilize your garden. You could also get a fish emulsion or sea kelp based liquid fertilizer from your local nursery.

Oaktown’s Greywater Guerrillas, another source for inspiration.

Greywater Workshop at Good Magazine

We’ll be doing a greywater workshop at Good Magazine this Wednesday May 27th from 7 to 9 p.m. Directions and RSVP info are here.

We’re going to focus on what I consider to be the easiest way to reuse your greywater: hacking your washing machine. We’ll take a look at a couple of approaches including our surge tank, pictured above, which we just got around to elevating with scrap lumber to get a gravity assist. We’ll also look at Art Ludwig’s direct “laundry to landscape” system.

Topics will also include:

  • Greywater compatible detergents
  • Choosing the best plants for greywater
  • Creating mulch basins
  • Greywater dos and don’ts
  • Plumbing parts
  • Water conservation and efficiency
  • Greywater cocktails (just kidding)

Hope to see you all tomorrow!

Make a Rain Barrel

There’s a lot of advice floating around the internets about how to make a rain barrel. Most barrel pundits suggest drilling a hole in the bottom of a barrel and installing a faucet, a kind of connection called a “bulkhead fitting”. Unfortunately such improvised fittings have a tendency to leak. My favorite way to make a rain barrel is to take a 55 gallon drum, use the preexisting fittings on the top and turn it upside down, a process explained nicely here (complete with a list of parts), by B. Chenkin who will also sell you a kit at Aquabarrel.com.

To get started, you get a ubiquitous 55 gallon drum with two threaded “bung” holes that look like this:

A good source for this kind of barrel is your local car wash. Just make sure that the barrel you scavenge didn’t have nasty chemicals in it. You punch out the center of one of the bungs, as shown, and insert a threaded PVC fitting. A few more PVC parts from the sprinkler section of your hardware store, a brass hose fitting with a valve, and you’ll have this:


Glue that up with some PVC cement, wrap the threads with teflon tape, and you’re almost ready to collect rainwater. But first, turn the barrel upside down, drill a hole for the down spout another hole to insert an overflow pipe made out of a threaded 3″ waste pipe fitting:

The last step is to prop the barrel up on some wood or concrete blocks to give some clearance for your hose connection and some extra elevation for a gravity assist to help push the water through a garden hose.

The overflow connection is another reason I like Chenkin’s design. It’s important to keep rainwater away from your foundation especially when, like us, you live on a hill. The picture at top shows our barrel installed with the overflow pipe connected to a pipe that runs down to the street. Los Angeles’ building code required us to run our rainwater out to the street, where it helps wash pollution into the LA River and the ocean (see creekfreak for more on LA’s pesky water issues). At least we’ll be channeling some of that water, via the barrel, to our new fruit trees. Those of you with flat yards could simply connect up an overflow pipe that would take the water at least ten feet from the foundation.

In Southern California, where rain never falls between May and October, a 55 gallon drum won’t meet much of our irrigation needs, though Chenkin’s design does allow you to chain multiple barrels together. What we really need is an enormous cistern, something with a capacity in the neighborhood of around 10,000 gallons. Ideally houses here, as in the ancient Roman world, would have been built with huge underground holding tanks. A small rain barrel like this makes more sense for those of you who live in places with rain throughout the year, where a small amount of collected rainwater could be used to bridge a gap in rainstorms. I put this rain barrel together as a test and because I was tired of looking a blue drum that sat in the backyard for a year giving our patio a methamphetamine lab vibe.

Again, for complete instructions and a list of parts visit Chenkin’s ehow page or, if you’re not adept at perusing the isles of the local hardware store, buy a kit from him through Aquabarrel.

[Editors note: due to spamming (are rain barrel enthusiasts really that excited about internet pharmaceuticals?) we've had to shut down comments for this post.]

Build a Solar Dehydrator


Like many of you, I suspect, we’ve got a few too many tomatoes at this time of the year. One of our favorite ways to preserve our modest harvest is with our solar dehydrator. There’s nothing like the taste of sun dried tomatoes, but unless you live in a very dry desert climate like Phoenix, Arizona you can’t just set fruit out in the sun and expect it to do anything but go moldy. In most places in the world, including here in Los Angeles, the relative humidity is too high to dry things out in the sun. Solar dehydrators work by increasing air flow to dry out the food. The one we built uses a clever strategy to get air moving without the use of electric fans such as you’d find in your typical store bought electric dehydrator.

Our solar dehydrator is constructed out of plywood and consists of a heat collector containing a black metal screen housed in a box with a clear plastic top. This screen heats up on a sunny day and feeds hot air into a wooden box above it. Vents at the bottom and the top of the contraption create an upward airflow through natural convection (hot air rises). You put the food on screen covered trays in the upper box. With sliced tomatoes it takes about two full days of drying and you have to take the food indoors at night to prevent mold from growing (a minor inconvenience). We built our dehydrator several years ago and have used it each season for tomatoes, figs and for making dried zucchini chips.

You can find plans for this “Appalachian Dehydrator”, designed by Appalachian State University’s Appropriate Technology Program, in the February/March 1997 issue of Home Power Magazine. The February/March 1999 issue of Home Power features a refinement of this plan, but we just built the original design and it works fine. The original plans and improvements to those plans are split between two articles: Issue #57 and Issue #69. You need to download and read through both before building this dehydrator. . Alternatively, the always excellent Build it Solar website has a whole bunch of solar dehydrator designs, including a nice cardboard version. And while you’re in the library there’s also a book by Eben Fodor, The Solar Food Dryer.

As an added bonus to the tinkerers out there, take almost any of these designs, remove the top box, stick it in a window and you’ve got a passive solar room heater.