A Rocket Mass Heater
I have been intrigued by Rocket Mass Heaters ever since I heard of them about a year ago. So what exactly is a Rocket Mass Heater? Well, it is a variation of a Rocket Stove (don't worry if you haven't heard of that either) combined with the concept of a Masonry Stove.
The concept is simple and brilliant. Wood is burned in a uniquely shaped "combustion chamber" that burns wood very efficiently. The heat produced from the burning wood heats up a large thermal mass (usually some form of bench). By the time the exhaust exits the room, it is only about 90 degrees F (32 C). The exhaust is mostly water and carbon dioxide.
Let me show you an illustration of a Rocket Mass Heater for better understanding:
Illustration of a Rocket Mass Heater
What are the benefits of a Rocket Mass Heater?
- Use a lot less wood for heating. The amount depends on where you live, but you can expect about one fourth to one sixth of what a very efficient fireplace or woodburning stove uses to heat a room/home.
- Almost no pollution. The fire burns so hot and intense, that only water vapor and carbon dioxide is released. And for you "Carbon Footprint" Nazi's out there, it is "carbon neutral". Clippings from branches in the yard or from branches fallen out of trees or even from coppiced trees is all that is needed in most cases. All that is left in the combustion chamber is a little bit of white ash.
- Better at keeping and sustaining heat. Almost 90% of the heat produced stays within the home instead of being lost out the chimney. The thermal mass can keep radiating heat for 12-48 hrs after the fire is out.
- Needs less tending. As the heat is radiating long after the fire is out, there is no need to tend the fire or watch for spitting embers.
- You need to build it yourself. There is no commercial version available now.
- It is heavy! The thermal mass being made mostly of clay/adobe is weighs a lot. You can't just install these anywhere.
- It uses clay/adobe. For some, this is great. For others, well, let's just say a Rocket Mass Heater doesn't blend will with a New World Colonial Design. (I actually have no idea if that is a design style or not, but it sounds pretty good!)
- They take a while to warm up. A big thermal mass can take up to 4 hours to heat up (but then it will retain heat for a long longer as well).
- Building codes don't really know what to make of this yet. It is a relatively new concept (2004 as I can best tell from researching it).
- You can get some "smoke back" when initially lighting the wood or if the Rocket Mass Heater is not designed well.
WARNING: Sloppy hippy alert. As is often the case, it is the more eccentric individuals who are the first to attempt/try new innovative projects like a Rocket Mass Heater. These individuals are usually hippies. These hippies are usually very messy or sloppy individuals who leave piles of junk all over the place. Unfortunately, it is hard for many people to see past this chaos and find the gem underneath. In my opinion, a Rocket Mass Heater has an amazing potential for energy savings. I think they need to be made a lot more attractive before they will be adopted on a more widespread scale, but what an amazing concept!
Here is a pretty good video that highlights a number of Rocket Mass Heaters (with the aforementioned sloppy hippies). It was done by Paul Wheaton of Permies.com.
This is just an introduction to the concept of Rocket Mass Heaters. I plan on providing more detailed information in the future. Stay tuned!