Are we all doing it wrong?

Complete combustion of the wood is going to result in heat and water vapour. If we are burning efficiently, then that is what we get, if not, then we might see particulates in the exhaust stream. Now, we could extract all the heat from the exhaust stream just leaving the water vapour to condense out and be collected. However, with a stove like most of us have, we want a hot stack because we might not be at 100% combustion and we worry about the tars being in the stream condensing out and forming a coating that could ignite and burn at some high temperatures that could damage our chimneys. For a rocketstove to avoid releasing tars into the stream; and note that the final exhaust is at a relatively low temperature, then it must burn at close to 100% or tars would be release and condensing out in the system.

 

Interesting discussion about efficiency. I’m not saying I agree with all of it. There’s a lot of anecdotal boast and swagger in the rocket mass heater movement but since it’s relatively new and a DIY community, not much rigorous data exists to back it up:

why the rocket mass heater works so efficiently (rocket mass heater forum at permies)

 

If he has a rocket mass heater, he likely also has a very efficient home with plenty of insulation with lots of solar gain on the sunny days and plenty of thermal mass to regulate temperatures. He may only need to run the system when it's cloudy for a few days in a row. I don't think the whole story is being told in that one video. Simply adding a rocket mass heater to a conventional is not going to gain the advertised efficiencies.

Good morning Brian.. up early huh?

 

As we age, certain physiological needs get us up during the night providing opportunities to post at strange hours.

 

Cool stuff!

 

I touched on this as well; if the system is closed, then the energy/heat does not leave the system; that is simple thermodynamics. Of course our homes are not closed systems but if we super insulate we can greatly reduce the energy lost. If we are losing 5 joules/hour, then we only need to put 5 joules/hour into the system to maintain equilibrium.

 

Some how I do not think that your interest is confined to the rocket stove.

 

Man, those are some big eggs, no? Right around the 4:00 mark.

 

I think in some of the videos she has less clothes on.

 

I have no doubt that the man could heat his home with one of these stoves, but first one clarification. He is building a rocket mass heater, not a rocket stove. A rocket stove has no mass and thus is used for cooking, a good friend from church builds many of these on his mission trips to Guatemala where his daughter is a missionary.

The second point to make is, the air in the mans home may not have to be 68 degrees. Because it uses mass, the man FEELS warm because of the radiant heat. If him and his girlfriend are sitting on the "bench" of the rocket mass heater (as it is called) he feels warm enough. So he might go a long time between recharging the wood.

Another thing is, they do not burn big sticks of wood, it is kindling at best and even smaller. That makes for an incredibly quick, hot fire. getting some reburn on the gasses and what not...sure he is gleaning all the heat out of it.

Myself I do not think I will ever have one. First, the stove itself would be the primary design with the rest of the house built around it. Myself, I want a stove to keep me warm, not the start of a new lifestyle. This might include living in a home that is just shy of a teepee...no thanks, my Indian Ancestor's left that a long time ago. But the last thing is, I am leery of them. You think I am silly for burning green wood, try installing what amounts to a wood fired blast furnace in your home that is homemade. I'll pass...but that is me.

And that is the truth, my little pot bellied stove heats my super insulated home for 4 cords per year. because I have the wood lot and logging equipment to do that with efficiently, I do not need to heat my home on 1/2 a cord of wood. This guy...yeah he has something to prove, and for a lot of people who lack the wood lot, or equipment...why not. But really it is a lifestyle.

 

I had to make sure that you typed boots and not ..... aw, you know!

 

yooperdave, I read in the coffee thread that you get a couple hours of accelerated heart rate from decaffeinated coffee and cappuccino. I agree with Eric VW- you better lay off the FarmGirl videos!

 

Nope, didn't need that fixed, I had it right!

 

Lay off? Didn't someone just say that there are vids with her wearing less??? Is that possible?