RMH Design and safety issues

I saw Paul Wheaton's YouTube videos regarding the Rocket Mass Heaters and was intrigued. I put a link to those videos in a forum that I am a part of to generate some discussion, and man, did I get discussion. Not all friendly. But I can understand their view. To them, it is new technology, and they don't have the information that might help them understand the whole process. These fellows are engineers, and they understand the older and new high efficiency wood stoves. There seemed to be two main areas of concern. The first was safety. Several of the men felt that the design would make CO poisoning nearly a sure thing. They were concerned that the mass robs heat from the system, and that the system might not be able to maintain the proper draft. Also, they were concerned that the cob used to seal the system would pull away from the drum over the riser and not make a good seal, allowing CO to enter the living space. The second area of concern was the potential problems with maintenance. The mass covers galvanized stove pipe that could be a potential collecting point for acidified moisture, which would eat away at the pipe.

Can anyone speak to safety concerns with the RMH, as well as why this design works efficiently and safely in your opinion. Also, please keep it simple to understand. I'm not an engineer, and it takes me a fair while to understand things. I eventually get it, but it's a slow painful process for both student and teacher! Have studies been made at Universities regarding the RHM? Have there been flow studies done, and chemical analysis of the exhaust done? Have there been any instances of sickness or death caused by CO poisoning due to a badly engineered RMH?

Any help would be... helpful? And greatly appreciated.

Doc, you should check out the "Rocket mass heater and butt warmer thread".

All these issues are discussed extensively there.

I am presenting on rocket mass heaters tonight.  Somebody from the county emailed me to remind me that firing something like that up at the library would be illegal.  I called him and told him that I was merely showing videos.  And then I asked him if we fired one up in a completely legal fashion, if he could measure the output. 

He told me that the contraption to such measuring costs something like $20,000, so there are only a few in the US. 

I think it would be really helpful to get some comparative numbers in this space.  Does anyone know of anything?

paul wheaton wrote:
I am presenting on rocket mass heaters tonight.  Somebody from the county emailed me to remind me that firing something like that up at the library would be illegal.   I called him and told him that I was merely showing videos.  And then I asked him if we fired one up in a completely legal fashion, if he could measure the output. 

He told me that the contraption to such measuring costs something like $20,000, so there are only a few in the US. 

I think it would be really helpful to get some comparative numbers in this space.  Does anyone know of anything?

Are you only concerned with CO2 emissions or are you interested in other gases as well?  I'm wondering if an automotive exhaust analyzer would do the trick?

Doc, just saw this posting.

There is not going to be a lot one can do to present an alternative view to these folks, I am in fact one of those folks, I have just a tad more "outside the box" in me than most in the engineering group, I infact identify as one whom believes there in fact "is no box" and it is only my obsessive compulsive behavior by the design of those whom made me that drives the "I have to know why" and the RMH along with the folks speaking of it in such a passionate manner and then they demonstrated clearly the average IQ in the group was above normal, it was clear I was missing something and I had to know what it was.

I could bounce over there and put a few on track and start them thinking, but I would much rather complete some testing to be able to prove in my lab the theories I have on internal operation. Once those are proven and explained, tossing it over there would make them ALL take notice instead of only a few.

It has not been yet made clear when some of the legal wrangling I am having to tolerate will come to a close, I suspect I am close to 60 days from its end, I do however have my lab manager starting production of some prototypes to destroy... I love mad science!

I would suggest you discontinue debate until we have some facts beyond experience and yes there are a lot more concerns than CO in the exhaust but CO is going to be the response you get from every single experienced combustion device engineer as it is by far the most common and dangerous element of combustion.

Icewalker wrote:
Are you only concerned with CO2 emissions or are you interested in other gases as well?  I'm wondering if an automotive exhaust analyzer would do the trick?

No sir, it might get a few heads to turn, but we science types like real expensive toys that allow us to be completely anal in our research and results from such a testing instrument would be totally discounted as typical expectations when employing substandard testing devices.

If you remember high school science, hypothesize, procedures, conclusions. We spec out our equipment as part of the procedures and even pounce on each other being critical of the recording of the data process.

For example, if you drove your car 200 miles and reported you got 30 MPG in 3.5 hours at X speed using X energy at X efficiency, it would be torn apart. Not listing the tire type, inflation rate, friction coefficient, calibration methods and equipment for the speedo, type and calibration for the timing device, oil type in the motor, measurement of exact actual distance traveled, bla bla bla, it would be dismissed, if you included it but failed to identify measuring process of the gas added it would be dismissed, if you had all your ducks in a row on all of that someone else would come along and say because you used gallons instead of weight and English units instead of SI it is impossible to calculate the entropy to the tenth decimal point etc. When all is said and done, the differences would amount to perhaps a half pint of gas and be completely irrelevant to 95% of the population, but unfortunately, you are dealing with that other 5% and the whole project would be considered nothing more than bad science lacking proper procedures.

Fair?, Smart?, Productive?, those answers do not matter. Reality? a resounding YES and simply knowing that hurdle exist can prevent you from wasting energies on methods that will not result in you reaching your goal.

Professor Rich wrote:
No sir, it might get a few heads to turn, but we science types like real expensive toys that allow us to be completely anal in our research and results from such a testing instrument would be totally discounted as typical expectations when employing substandard testing devices.

If you remember high school science, hypothesize, procedures, conclusions. We spec out our equipment as part of the procedures and even pounce on each other being critical of the recording of the data process.

For example, if you drove your car 200 miles and reported you got 30 MPG in 3.5 hours at X speed using X energy at X efficiency, it would be torn apart. Not listing the tire type, inflation rate, friction coefficient, calibration methods and equipment for the speedo, type and calibration for the timing device, oil type in the motor, measurement of exact actual distance traveled, bla bla bla, it would be dismissed, if you included it but failed to identify measuring process of the gas added it would be dismissed, if you had all your ducks in a row on all of that someone else would come along and say because you used gallons instead of weight and English units instead of SI it is impossible to calculate the entropy to the tenth decimal point etc. When all is said and done, the differences would amount to perhaps a half pint of gas and be completely irrelevant to 95% of the population, but unfortunately, you are dealing with that other 5% and the whole project would be considered nothing more than bad science lacking proper procedures.

Fair?, Smart?, Productive?, those answers do not matter. Reality? a resounding YES and simply knowing that hurdle exist can prevent you from wasting energies on methods that will not result in you reaching your goal.

  I knew there was a reason that science classes gave me the deer in the headlight look

There are so many variables. 

Perhaps one unit of measurement would be to measure the exhaust for 100 pounds of wood being run through a conventional wood stove (CWS), and then 100 pound of wood through a RMH.

For the CWS, one round could be kindling sized wood; another round could be normal sized wood and try to get the hottest burn; another round could be to try to get the slowest burn.

For RMH, one could go for all kindling, and one could go for something closer to normal. 

Hmmmmm...  I keep thinking about how, on the one hand it would be good to just get these numbers, and on the other hand, it would be good to better approximate actual use. 

I think that when a CWS might burn all day, a RMH might burn for an hour in the morning and an hour in the evening. 

So, 100 pounds of wood run through either system might generate the same amount of lead in each.  But the RMH will heat the same space with much less wood. 

This does get really complicated, really fast. 

I suppose the proper test would be to run the same amount of wood through each system and then measure the output.  Of course, exhaust temperature output could also be measured.  So, the conventional wood stove would generate X pollution and T heat exiting the building (temp and volume).  The same amount of wood could be put through the RMH and the same things measured. 

I had another idea. 

I wonder how the pollution from a RMH compares to the pollution caused by heating your home with electricity. 

And ... for the short term, I wonder if we have any ballpark numbers for a RMH compared to a CWS.

I have no doubt the RMH has a more complete combustion than a CWS and I have a feeling it can indeed flirt with the CAT systems as well on the major pollutants.

The reason CO is discussed so much is because there is a lot of it and it is so nasty and unforgiving, once you have too much you are dead, no amount of first aid or oxygen can be pumped into your body, you might be alive but within a few short hours you will in fact die.

A vast amount of combustion analyzers are not going to be effective for proof. This is because they are calibrated to CO, meaning they accurately read the CO, however they use averaging software to determine the other elements as they would be typically in % ratio to the CO level.

If we can prove some seriously low levels of all of the pollutants, we MIGHT be able to spark enough interest to get it looked at in depth.

Its sort of like what has happened with sugar, replaced with saccharin first, oops a mistake, now replaced a lot with high fructose corn syrup and diabetes is on the rise like no tomorrow. No one is going to back up claims that are not founded in good science. The lack of CO does not mean less if not more of the other nasties involved. I do not think so and even see some evidence that may indicate they are reduced even further, but it has to be proven and the step to getting that done is to prove the operational parameters and use some equipment that is respected so that fostered interest is not dismissed.

Rich,

Do I remember correctly that you might be holding a ruler up to this soon?  You might have the equipment to report what a rocket mass heater spits out?

paul wheaton wrote:
Rich,

Do I remember correctly that you might be holding a ruler up to this soon?  You might have the equipment to report what a rocket mass heater spits out?

That is correct Paul and actually as of today I have a date when I can shift my focus off the other crap getting in my way March 2nd. it is my understanding I have a three day window on that and then the dust shall settle.


I will not be able to identify all of the components, however I can go well beyond software guesstimate.

My goal is one in three basic parts, proof of concept on actual operation of RMH, proof of decreased hazardous materials in exhaust, flexibility in sizing configurations of the units based upon maintaining the operation, there simply has to be a way to predict parameters required to alter the output of the unit to make it more practical for a variety of uses.

Rich,

Curiosity makes me ask if you have been able to do any of the work you were planning???
I am very interested in hearing about the work and results.