Justin Hadden

Jordan Holland wrote:I think the issue with what you are describing is that when a given amount of wood is heated to the proper temperature for combustion, it becomes a gas at a certain rate. Air must be fed to the fire at a certain rate to keep up with the off-gassing of the wood for clean combustion. The only practical way to keep the mixture correct and draw out the time of burn for a given amount of fuel I can think of is to use the smallest core possible.

Jordan this is a good point, as i mentioned in one of my replies above maybe it would be possible to expose less fuel to the hot zone at once in order to lessen the off gassing without sacrificing the amount of air needed for complete combustion

Phil Stevens wrote:We are using all three Ts, but the time part is served by the mass. Hot, fast, clean combustion with some means of storing that short-term burst of heat energy in a form that is useful to the space and inhabitants over a longer timeframe.

Phil you cant count the mass as the t for time as it has no effect on the combustion process.

C. Letellier wrote:Actually time is taken into account 2 ways.  The thermal mass acts as a battery giving the heat long term to the home.  Height of the heat riser generating a sufficient burn time.  And it isn't really an oxygen rich flame.  The physical structure acts to limit it to just barely oxygen rich flame.  Look at the NOx data.  On oxygen rich flame generates lots of NOx.  A RMH running properly produces very little.

You can't make the thermal mass the T for time. We're talking about combustion only. The thermal mass has nothing to do with the combustion process, only the heat storage process. Granted the heat riser does add time, but it also adds height and takes up space in the home. The thing i was trying to get to was something that could be used by people that can't have an rmh in their home. If you cant have a big thermal mass in your home, than the only other option is slow the burn even more so that it can have more time to radiate into the room before exiting the flue.

By design an rocket uses wide open air, obviously ypu can't choke this off to try and slow it down otherwise we end up with a smoky and dirty burn. What about somehow controlling the fuel supply? Just as a diesel engine has wide open air at all times by design, it controls its fuel quantity instead to throttle things. What if somehow we could expose less fuel to our wide open air in order to have a slower yet still complete burn, by not throttling our air we would always have ample supply to complete combustion, no idea how it would be done, just thinking out loud.

Hi all, the more i think about rocket stoves/ rocket mass heaters, the more i get an itch that perhaps theres a way we can change things to work for different peoples applications.

I've read many different posts of people who have various reasons for not wanting an RMH. Some don't like the look of them, some peoples floors cannot handle the weight, some don't want to babysit it for the 1.5-2 hrs of burn time needed, and some don't want to risk voiding their insurance. These are all valid points to have, and i wouldn't fault anybody for any of these reasons.

When i was in school for my mechanics trade and we were learning about engines, we learned the three Ts of good and efficient combustion:

-Time
-Temperature
-Turbulence

In an RMH, it seems that we achieve extremely clean combustion by only utilizing 2 of these 3 Ts. We use turbulence in the burn tunnel and riser, and we use extreme temperature by means of insualtion. In other words, we burn hot and fast. In my opinion we are probably actually pushing the temperature part higher than we have to in order to make up for the lack of the "Time" factor.

With all the great minds here, it would be curious to see if collectively a design could be made to burn efficiently with all three Ts in place. In other words, a very hot, very clean, but SLOW burn. Perhaps I'm wrong, but i feel like if we slow things down, we may not require the extreme temperatures we are currently using. The current design is essentially an oxidizing flame, which anyone who has used a cutting torch knows is the hottest flame, even hotter than the perfect mixed flame. What this hot oxidizing fire allows is for the burn to be clean in spite of the fact that its burning FAST! Remember, we arent burning clean because we are burning fast, in the science of combustion slow is your friend, what we've essentially done is found a way around the fact that we've almost completely eliminated one of the Ts from the equation.

If something like this could be figured out, a way to burn hot and slow, it may allow other people who can't or won't build a convential RMH to have a cleaner/ more efficient option than on the market woodstoves currently out there. If we could make something that burns clean and slow, it may eliminate the need for quite so much mass that is always a big concern for people and their floors.

Anyways, just a couple thoughts that i figured I'd write down to get them out of my head.

John C Daley wrote:
I think your original statement may be incorrect, but I have seen similar laws around the world for cleaner burning units.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www2.gov.bc.ca/assets/gov/environment/climate-change/action/cleanbc/cleanbc_roadmap_2030.pdf&ved=2ahUKEwiV25qCq4P7AhVAFTQIHQUWBTwQjBB6BAgPEAM&usg=AOvVaw1pAC33eQRGDnVMa9bBS6_O

Its a long read, but if you skip down to page 40 and start reading there, it says "after 2030, all space and water heating appliances sold and installed in BC will be 100% efficient."

So you have to read between the lines, no combustions technology, whether wood, pellet, or gas can ever acheive 100% efficiency. The only truly 100% efficient systems are electric. Electric resistance heat converts 100% of its input energy into heat. Its a terribly difficult way to heat a space, but on paper i guess to them it looks good. The other funny thing is if you were to trace back all the way to the power plant (which is combustion technogy) then its probably even a less efficient process to heat my home electrically then it would be to simply have a wood stove in my home.

If you contjnue reading i believe on page 42 it talks about giving labels to everyones homes and giving it a carbon footprint rating for sales purposes. Meaning if some career political wannabe in a suit decides he doesnt like the way my household heats or cools or whatever they can give me a rating that will seriously affect my sales price.

Unfortunately with these things the government will hide the agenda deep in the text, i suspect as a way to avoid pushback. That seems to me to be exactly whatthe government of British Columbia are doing. Bury it in a massive document, and then most people will be taken by surprise by the time it comes to pass.

I'll tryto dig up what i was reading.

Hi John, yes it's quite a frightening proposition. It definitely has not been thought through properly. Between these goals to make a certain percentage of cars all electric and now the push to make all heat and hot water systems electric as well, the demand on the power grid will be absolutely enormous come winter time in the future.

The other scary thing that has to be considered is that not only would this increase the likelyhood of rolling blackouts due to shear demand on the electrical grid, but we are also not strangers up here to having power outages in bad winter weather already due to ice, snow, car accidents that take out power poles. Should you lose power in minus 30 degrees celcius and your main heat source is electric, the very real possibility of freezing to death will arise.

What i would like to do is try to develop some sort of wood and or pellet heating system like I described before and possibly bring it to the provincial government as an alternative to their proposed ban on wood heating appliances.

I know this isn't about RMHs, but i'm looking to get a wider opinion, and i know this forum sees a decent amount of traffic, so please move it if you feel its inappropriate.

I've been interested in the idea of biochar for some time, i know others are as well either for garden applications, some people for charcoal gasification. The process of making it however is ever so wasteful. The most useful way ive found is putting a tin can in the woodstove in order to capture the heat giving off in the biochar producing process. This however yields such small amounts of biochar, which is why inevitably people tend to switch over to the most wasteful production methods in the end.

For a while now i've been throwing around the idea in my head of producing a type of wood stove that can take full sized firewood splits and turn all or most of it into biochar, while at the same time heating your home or space.

However it seems the more i think about it the more discouraged i get about the idea, convincing myself nobody would be interested in it. I think that people won't want to deal with the inconvenience of removing the char out of the stove after the burn is complete, or that they won't like the idea of a 30% reduced burn time. Charcoal makes up about one 1/3rd of the weight of a piece of wood, no naturally even in an efficient design your burn times will only be 66% what they would be if burning the entire piece of wood including the charcoal.

My other big reason for doing this, is that my province in canada has come out with the plan of banning wood and pellet heat by the year 2030 as part of their climate change fighting effort. Not only wood and pellet, they wish to also ban all natural gas and propane appliances also, everything will be ele tric. This made me extremely sad and even a little angry, the cost of living recently has absolutely skyrocketed, energy prices have soared, and here they are going to take away the only affordable means of heating our homes in the harsh canadian winters. You can bet that electricity prices will increase exponentially by the time we are all forced to make the switch.

That brings me to my other reasoning for this idea, the biochar process i've seen has been considered a carbon negative process. A dead tree left to rot in the forest will eventually decompose into CO2. If biochar is made from that tree and subsequently buried in the garden, it will take 100s of years or more for that char to decompose into CO2. This means you can still capture the heating value of dead wood and biomass, without the huge release of CO2 in the process.

I know it may not be perfect, but my thinking is a system can be built that still allows us to cheaply heat our homes and in the process combat climate change, then surely it must be worth it. Because at the end of the day as much as many people wish to do good for the environment, sky high costs of heating will make it harder to live than it already is, and i feel horrible that there isnt something we can do to satisfy both needs.

Anyway, thats my long rant. Please let me know what you think. Is this endeavour worth it? Do the pros outweigh the cons? Or should i save my time and money and pick a new dream to follow?

Thank you for your time.

Not sure why my last reply formatted the way it did, tried to fix it but no luck haha

paul wheaton wrote:

Maybe we need a video (or find an existing video) of somebody reporting that they had a stove like what you describe and they switched to a rocket mass heater.  They can then describe the amount of wood from before, and the amount of wood now.  "I am warmer now and use about 80% less wood."

Yes that would be great! The thing is a good RMH or masonry heater is probably pushing the low to mid 90% range fof efficiency, these new stoves are around 80% effficient or so. To some i think 10% or so gain doesnt sound like much, but even 10% in the world of thermodynamics is a massive jump!!

Maybe somebody here has already made the switch from an epa certified stove to an RMH and could chime in.