What in the heck is a rocket mass heater? Well, it’s this super groovy way to efficiently heat a living space or in this case a greenhouse. Some reports suggest that a rocket stove mass heater is 75-85% more efficient than a standard wood burning stove. Rocket stoves are mainstay in third world countries where regulations, rules, and bureaucratic bologna don’t get in the way of sustainable living. I think of a rocket stove as being similar to a U-siphon in plumbing except in this case it’s siphoning hot air instead of water. The diagram below shows the basic air circulation in a RMH
The original plan for heating the greenhouse was to use 55 gallon water barrels along the back wall of the greenhouse but that proved to be insufficient for heating both the air and the water simultaneously. So with numerous sleepless nights and mild panic attacks, I stumbled upon the silver bullet of space heating, maybe. I have been counting on the RMH to resolve a few of the challenges of growing in a greenhouse: 1. basic heat of the air, 2. heat the water for the fish in the aquaponics, 3. reduce the humidity which resulted in a massive mold problem, and 4. it’s extra fun to watch stuff burn, especially all the scrap wood iv’e been hoarding in the nooks and crannies of the yard. So let’s get on on with the build.
I started with a standard burn design that can be found all over the internet. Permies.com is a great place to start. I suggest that you keep all of the piping at or near the same dimensions and be flexible to adjust the dimensions as you go. Every design might be a bit different so be flexible and ready to troubleshoot your stove. My greenhouse is at almost 7000 feet above sea level at the base of Pikes Peak so it took a few adjustments to get the system working. Here are some pictures of the process.
As you can see, There were some modifications toward the end of the pictures.. I found that the vertical feed chamber did not work very well so I went with a horizontal feed chamber that has been super groovy. The plan is to put in a raft grow system that will be connected to the aquaponics system in the bed that sets above the mass heater. If all goes well, The RMH will be able to heat both the air and the water. I’ll revise this posting later but for know, I’m done.