When disconnecting from the grid one of the most important issues we need to deal with is ‘how do we heat ourselves in an environmentally sustainable way when it’s minus 40 outside?’
Our present technologies have all been too polluting - oil, wood and yes, even natural gas (https://www.technologyreview.com/s/423661/just-how-green-is-natural-gas/).
One of the best alternates we’ve found is passive solar design combined with huge amounts of insulation. But this has two major drawbacks. First, we would have to rebuild all of our homes. Very impractical and costly from both an ecological and a financial point of view. Second, we may hold heat for a long time but given heat loss from merely opening the door there would still need to be some heat input over a winter's night.
I find the most practical solution to our “crisis of heat” is a rocket mass heater. After burning wood for hundreds of thousands of years we’ve learned a few things. Rocket mass heaters use 20th century technology to produce heat, substantially reduce the air pollution and yes save our resources (including our forests!) in the process. A tall order but something worth looking into right?
The rocket mass heater has a burn chamber unlike anything you see in today's commercially available wood heaters. It has specific ratios of the length of the burn chamber, the feed tube and the exhaust portion that creates a draft which brings the burn process to such a high temperature that 99.99% of the particulate matter is burned. In other words, you seldom have to clean out the ash. And as it’s burning the heat from the core of the rocket mass heater goes through a length of metal pipe which like any fireplace sends the exhaust outside. With a RMH that exhaust is only a few degrees above room temperature meaning that all that heat was released between the burn chamber and the exhaust end.
This when combined with a thermal mass creates a heat system that soaks up, then releases heat slowly over time. The thermal mass most commonly used is cob (aka adobe aka clay). Since clay is basically everywhere this part is very inexpensive. Aside from it’s easy availability clay can be formed to any shape you like.
So it works like this; build your RMH core, connect the metal exhaust pipes, run those pipes through a mass of cob before exhausting out the flue. So when operational the heat moving through the pipe will transfer through to the cob. The cob, in the form of a bed or seating area provides an excellent medium to capture and slowly release that heat.
Voila! A heat source that emits minimal pollution, uses resources in an efficient way (1/3rd that of regular wood stoves), can be built by anyone on a limited budget, can act as a truly warm bed in winter and can be retrofitted to existing homes. Who needs high tech to be sustainable?
Gilles Leclair is the founder of GeoStudios. Somewhat eccentric, fairly environmentalist, politically aware, he believes the world should have more off-grid communities... many more.