Ecology: Rocket we go!

Bright orange and sudden pain. That pretty much describes what I saw and felt the moment I almost got a hot spark in my eye from the circular saw. It luckily missed my eye by a centimeter. Definitely taught me a quick lesson in why safety always comes first. I was holding a piece of metal when Bernard was cutting it in the right shape for our rocket stove. Of course he had a pair of safety goggles on. Next time he won't be the only one. Working gloves would've also been nice. Certainly when a piece of your skin gets between the chisel and hammer you're working with.

"Wait, rocket stove you say? What's that?"

Glad you asked. It's a type of wood stove that I came across a while ago during my never ending searches on the internet on ecological practices. I'm very enthusiastic about this type of stove because it's extremely efficient, very ecological, really cheap (even free if you play it well) and is pretty easy to build, which we are doing right now in a sauna.  

The only basic materials you need are a couple of steel barrels, steel pipes, common bricks, sand, clay (in our case we're using loam), straw, water and some tools. That pretty much covers it.

The basic principle that makes a rocket stove different from a regular wood stove is the chimney, also called the heat riser. Instead of placing the chimney outside of the stove you put it INSIDE the stove. Because of this simple principle almost all the exhaust gasses are captured and thus a lot more heat. With a regular stove all the warmth goes through the chimney and up to the skies, which is pretty inefficient when you think about it.

You'll here two different names pop up often for this type of stove: "rocket stove" and "rocket mass heater". The difference between the two is the purpose of the stove. If it's mainly used for capturing heat through mass and thus keeping the warmth inside your house, you'll here rocket mass heater more often. If it is mainly used for other purposes, like cooking for example, you'll here rocket stove. It's also often used as a synonym, though.

With a rocket mass heater the heat goes up the heat riser and is then pushed down through a long pipe system encased in cob (mixture of clay, sand, straw and water) which captivates the heat inside it. Most of the time the cob is shaped like a bench, so people can sit on it and enjoy the warmth coming from it. Because of this you are able to capture a multitude of heat compared to a regular stove and you need up to four times less wood. Yes, four times less sounds crazy, but it's really that efficient!

Here are some pictures from our visit to a rocket mass heater and our first work day: link  

My advice to anyone who's building or wants to build a heat system for their house: Go rocket! You'll make your life much easier! Check Youtube if you want to see some rocket stoves or rocket mass heaters into action.