1742 The Rocket Stove - Explained and Demystified #rocketstove

Another point that is often missed: An ordinary wood stove, once the burn is established and going, burns its wood on the entire surface of the firewood. The rate of burning is mainly controlled by the reduction of the airflow to the burn chamber. This leads inevitable to a less efficient burn. The Rocket Stove on the other hand burns its fuel (if done/loaded right) always with the maximum amount of air it can possibly get - but only at the tip of the firewood. As I said, a small detail often missed out concerning Rocket Stoves/Heaters and their efficiency. Greeting from Germany - love your channel!

Working as a welder in stainless steel a while back I made a small rocket stove, 2x2inch sq tube. I then put the stove inside a box, intake and exhaust flush welded to two sides. I added a spout to one end, and a handle to the other making a tank that holds about a gallon of water that can be poured easily. Great camping stove, I can boil tomorrows water while I cook tonights dinner, with only a few handfulls of twigs.

We have a Slow Combustion (pyrolysis) stove for heating, and a bloody great hub off a harvester outside as a "fire-pit" for enjoyment, because when its all said and done, there's something cathartic about staring into the dying embers of a mallee root open fire! Greetings from rural South Australia from a fan of your channel; thanks for such interesting content.

I do blacksmithing as a hobby, and to make charcoal for my forge (I’ve since switched to propane), I settled on a method which involved a large pipe, about 3 feet (1m) long, 2 feet (65cm) in diameter, and 1/4 inch (7mm) thick, resting on 3 inch (8cm) metal spacers to allow airflow. I’d build a small fire in the bottom, and once it got going I could throw in bigger and bigger pieces of wood, filling the pipe right up. The heat from below would bake the wood on top and release gas, which would burn as long as the bottom wasn’t clogged with ash and debris. The flame from the burning gas could get up to 4 or 5 feet (over 1m) above the top of the pipe. And large spots of the pipe (which is quite thick, remember) would actually glow cherry red. To stop the process I’d remove the spacers (easier said than done) and place an oil drum with its’ top removed upside down over top of it to smother the fire. It was quite interesting, and I did my best to use some of the principles of a rocket stove.

The Fin oven is a kind of rocketstove with downdraft. Very popular in Scandinavia. With downdraft section the hottest gases will stay in the upper chamber, while colder gases that did their job, leave through the chimney. In the eighties I visited a monastery in Kyiv, they had a HUGE wood fire oven in the cellar. The heat was trapped in a second "stove" consisting of just a hollow structure. Heat was dissipated in the walls, somewhere on the low side of this chamber was the escape for the gases. This construction continued for six floors. They started heating in August and only beginning of October the walls started radiating heat on all floors. Very huge stove, very huge monastery, very impressive! In March they stopped heating, the monastery kept warm until the beginning of May. The monk who designed the stove was Kuznetsov, so they called it the Kuznetsov stove. Built somewhere in 17th century. Apparently the system to preserve thermal energy by downdraft was known when they built the monastery.

Another GREAT Conversation! Thank you for sharing :) Regards.

I was looking for someone to explain in great detail why its better how it works and the history behind it. You sir are amazing for this

The best explanation I’ve heard for a stove…. Thanks

The issue of balancing different contrary demands is the essence of engineering. Very nicely presented!

The barrel part in your Mass Rocket Heater example releases heat right away - no waiting for the "Mass" part to capture, hold and release heat later over longer periods of time. That's the way I understand the system anyway. Terrific channel!

A big advantage of mass heaters is that they produce radiant heat not so much convecting hot air which can be lost easily, when doors open and to the ceiling. They transform, fast high temperatures (as you say) into much lower temperatures for long periods, that are more amenable to body comfort and health....a problem with metal box, high surface temperature wood burners is that dust burns on the hot surfaces and is convected into the air resulting potential respiratory issues, also the fierce heat drys the air causing further problems. The Roman Hypocaust and the ubiquitous northern European masonary or tile stove have much to recommend them for space heating purposes, albeit they take time....

I like the idea of capturing and radiating as much heat as possible so I intend to experiment with those stacked 240 litre steel drum wood burners I've seen other pyromaniac youtubers build. I think they're referred to as 'double barrel wood stoves' but I'd like to continue stacking.

If I only could send you a small video from. 2 years ago..a ramshorn in a so called pizza oven.. super insolated control of slow fire and adding a lot of stones around.. later introduced a heat transfusion with a water spiral to feed the CV. I left the guy with whom. I shared my suggestions and support because he had1000 things else to do. This is a hell of a product. I stil love this hell of a fire stove so easy burning..you can open the heart and the oven without danger or distirbance. Ideal Too hot for a single simple home.. You ll have to share with neighbours. I wish I could send you a video.. Thanks for your concerns and information. I love it, Fredy

Robert, as you say, the key attribute of a Rocket heater is the efficiency and the clean burn of the gasses given off by wood in the initial fire. I assumed that it would be beneficial (necessary ?) to insulate the chimney to encourage that secondary burn to reach the temps of 600-1200 you mention. That then leaves you with some pretty hot gases coming out of the top and, by enclosing the chimney with an inverted can, you retain the heat to help keep the chimney hot but also radiate into the room and (for a rocket Mass heater) exhaust into a further heat recovery and storage area viz. the "mass", extracting most of the heat from the exhaust before it leaves the building.

A rocket heater (without a mass) is good for a woodshop. A rocket mass heater is good for a home. A typical rocket mass heater puts out 70% as immediate heat and the rest into the mass.

Watching your videos helped me refine my tire burning heater, so it doesn't give off black smoke anymore. It burns clean and since used tire are nearly free, I can heat my garage for a lot less and tires don't need to be seasoned to do the job like wood does. And there is a benefit of keeping tires out of landfills and free scrap metal to cash in at the metal recycler.

Best explanation ever! Thank you!

YOUR VIDEOS ARE THE BEST THANK YOU

Hold on.... mass heaters still exist in 2022??? I remember in the 1990s helping a family heating business, one of the things we often did was rip out the myriad of mass heaters put in houses in the 1950s and 1960s, when electricity was indeed cheaper overnight. I dont know of anyone installing a 'night rate' meter in a house from the 1970s or beyond!

Rocket mass heaters have the advantage of giving a portion of instant heat, at least the ones with the steel drum in the build and storing the excess heat in the mass thereby utilizing the most efficient fast hot complete burn. A lot of the energy in wood burnt in woodstoves that are damped for the evening goes up the chimney as smoke and soot. If it didn't loose that energy you'd not have the phenomenon of a chimney fire. Exhaust from an RMH is also often at about 40C (100F), significantly lower than a wood stove so retained heat efficiency is also improved. Thus a few of your comments were just a bit off the mark.