Can a BBMH heat the living-room and a lean-on greenhouse at the same time?

Heya dear fellows,

Im planning to build a BBMH into a 5.5m long wall. The current desired build is something like a 6" to 10" batchbox, with perhaps, a smoking chamber or other nifty gadget. It will produce an amount of energy from ~1.9 to ~5.9 kW/day and burning ~7.1 to ~19.5 kg of wood/day. Their ISA bell size (the area of the 5 faces of the chamber, discarding the bottom face or floor of the chamber, since it shall not heat proportionally) ranges from 5 m2 in a 150 mm system ~to 10.85 m2 in a 220 mm system. It will be at the ground level, inside a greenhouse built as a chinese greenhouse style. It will "emerge" from the floor of the house up to the required height for the desing, with a maximum height of 2.4m.

Those are the house planes so far. It hasnt been built yet :v any suggestions about the BBMH or about anything else? The house will be located in someting equivalent of a hardiness zone 9b, rarely hitting freezing temperture but mostly cold with considerably hot summers. Here you can see the weather(as a humid version of Fresno? dont trully know, im from a city named Chillan, in Chile).


This are the current dilemas:

-¿How can i extend the horizontal array of bells in order to produce an optimal, yet uneven, flow of caloric energy thru the mass?

-If you can use as many bells as you want (as ive read a few times now), ¿can you use 2 to 5 columns of 2 vertically stacked bells? Being 4 to 10 bells in total.

-¿Can you place the other bells in an horizontal array if the main and second chamber are stacked vertically?

-¿How many bells would be appropiate?

-¿How many vertical bells would be the best?

-¿How much is the exhaust draft. aswell as heating distribution and other impactful factor, modified by the fact that it will be using two kind of arrays of bells, horizontal and vertical orientation? Im planning to add electronics in the future, as an autopowered fire-starter assit fan, powered by the thermal difference betwenn the mass and a cooling sinc, applied to a peltier plate, for example. With this kind of equipment you might aswell automatically start the fire at a given time, regulate the P-channel or whichever air intake is pertinent in order to optimize the gas components thru the combustion period. The amount of upgrades is unlimited.

-¿Which display of bricks would be better for this purpose? I would imagine that something in a "wall" shape would transfer heat more efficiently to 2 rooms, rathen than a huge box, since neither the lateral sides nor the bottom face of the boxes will be in direct contact with neither of the rooms. Only the front, rear and top face will be facing one of the two rooms. I fact, only like the 65% of ther rear face will be in direct contact with the living rooms area, since the missing % is below the lifted-floor level. In compensation for the missing area of contact of the wall inside the house, the majority of top face of the BBMH will in direct contact with the livingroom aswell.

-¿Which is the most reasonable lenght for it to be?

-¿How can i accuratedly calculate the temperture of the desired gadget (cookstove, oven, smoker, water coil, etc) match the temperature of the bell you place it in? For example, if i wanna install a smoker, i would think that the main bell and maybe the second are far too hot for the purpose but maybe the later bellls would be too cold. The access is by inner side of the house, and not thru the greenhouse.

-¿Considering the bricks used for this kind of heater have a different density  aswell as heat retention capacity, compared to COB. How much volume of BBMH equals a given volume of J-tube COB RMH? I know this is a really tricky and indivual properties-dependant question. But i bet somebody already has estimated the sizes in an avarge comparison. A dense fire brick has an energy density of 2.52 kilojoules per cubic meter per degree Kelvin [kJ/(m3K]. A light fire brick has an energy density of only 0.36 kJ/(m3K). By comparison, an ordinary red brick has an energy density of 1.4 kJ/(m3*K).


I really really appreciate all kind of ideas, information, corrections and opinions

Thanks in advance, Agustino

Cannot see why not in principle as I know both in France and the UK walls heated with fires  were used to grow stuff like figs and peaches until recent times

David

Your diagram shows the bedrooms rather far from the RMH.
Is the RMH supplemental heat, or primary?

William Bronson wrote:Your diagram shows the bedrooms rather far from the RMH.
Is the RMH supplemental heat, or primary?

Primary, and i hope, only
I expect the living room area to be my working station (the table is drawn there for the sole purpose of helping me to visualize proportions), only using the bigger room to sleep (knowing myself i might end up using the guest room lol), and the guest room as a rarely used space. Eitherway i expect relatives and freinds to come over so decided not to build the smallest room ever. Furthermore, i might be thinking naively, but i have never suffered from cold while sleeping at all, if anything is the opposite, so i dont trully see the profit for heating the rooms since one will be used for sleeping only, while the other will be mostly unoccupied.
Therefore, i thought about combining the wall of the greenhouse, in which i have many expectations, with the living room-kitchen (studied to be a cook). Given that the greenhouse orientation should be facing north (keep in mind that this place is at the height of New Zeland on the globe.
Thank you pals so much for the answers, ill keep checking regularly thanks
PD: sorry the plane is in spanish, it was not meant for this jijiji

Posting the image here for easier reference.

Satamax Antone wrote:http://heatkit.com/research/2009/lopez-rocket.htm

Sorry for not answering earlier, but i read the information as soon as i saw it jijijiji. Even tho it provides me with tons of useful material, does not quite help me with this given goal. That is because the RMH from the link is inside the greenhouse, whereas im placing it behind a brick wall. Also, they constructed a regular RMH only for the greenhouse but im trying to build a 2.5x tall one to heat 2 spaces.

Thanks a lot for the contribution and i really really hope you guys keep proving the always treasured guidance.

What is your plan for the rocket size?

Because, 3.9m long. Lets say 2.15 m high, or so . Internally, 3.7x2, X2, plus the ends, you're already at more than 15 m². That's a lot of surface for a bell.

I'm about 11m² altogether, with a 220mm batch rocket. When hot at 45C° on the outer skin, which takes a good 5 hours burning. it takes 2 whole days to cool down to ambient (usually around 13C°)

So, you need a big rocket to power what you are planning.  

Satamax Antone wrote:What is your plan for the rocket size?
Because, 3.9m long. Lets say 2.15 m high, or so . Internally, 3.7x2, X2, plus the ends, you're already at more than 15 m². That's a lot of surface for a bell.
I'm about 11m² altogether, with a 220mm batch rocket. When hot at 45C° on the outer skin, which takes a good 5 hours burning. it takes 2 whole days to cool down to ambient (usually around 13C°)
So, you need a big rocket to power what you are planning.  

Thanks for your reply, Antonio-san. Tho, im not quite sure whats the reasoning behind that heating/cooling time and the rocket size. If you could extend your explaining would mean a world to me, im always eager to learn.
:v Ive also added the most recent version of my planes, so the sizes might have changed from what you saw at first.

It's not juste heating cooling time.

In a bell,  you have inside, the heat extraction surface. Called internal surface area, or isa. If  the surface is too big, all the heat is extracted, and there's no power left to maintain the draft. Thus leading to smokeback.

Besides this, there's mass. And outside radiating surface.

http://donkey32.proboards.com/thread/2174/size-batchrocket

http://donkey32.proboards.com/thread/1822/sizes-single-bell-systems

http://donkey32.proboards.com/thread/1103/dew-point-flue-gas

http://donkey32.proboards.com/thread/1363/intresting-stuff-mha-mass-sizing

http://donkey32.proboards.com/thread/1359/bell-explanation


http://batchrocket.eu/es/

Once you have read all this, you might be sort of up to date.

Satamax Antone wrote:It's not juste heating cooling time.
In a bell,  you have inside, the heat extraction surface. Called internal surface area, or isa. If  the surface is too big, all the heat is extracted, and there's no power left to maintain the draft. Thus leading to smokeback. Besides this, there's mass. And outside radiating surface. Once you have read all this, you might be sort of up to date.

Altough i havent finished reading all the info you provided me, i noticed that the numbers you used to calculate the volume of my RMH are quite off, since you used a width of 2 meters!!! Im not building The Mecca jojiojioj.

The actual planned size (modified constantly, im thinking about adding more lenght on the mass, if that would be somehow doable) is 3 x 1.45 x .6 [m], obtaining a total mass volume of 2.62 [m3], being 2,33 [m3] of COB and 0.287 [m3] of pipe and about 4 [ton] mass weight. Im always rounding up to the numbers to the punishing side.

One problem is, the total lenght of the pipe, measured from the joint of the pipe to the barreldrum to the tip of the exhaust pipe cone, is 11.35 [m], considering each elbow as 1.5 [m] it would give me an extra 9 [m] from 6 elbows, (considered the first and the last elbow as only one, as they deviate only 45° from the flow, each). A bit more than 20 [m] is too long? Ive read that the desired lenght for a 8" pipe RMH is not further than 15 [m]. If we do not consider neither the first nor the last semi-elbows, aswell as not considering the lenght of the pipe once its out of the mass, the total lenght would be 16.5 [m].

Im not sure at all how could i determine the temperature using theory.

Ill continue with the homework Im deeply grateful for help you have provided me. Here, where i live, nobody has never heard of anything similar to a RMH, so this forum is like a golden well.
Thanks :v

Augustin, don't do this with pipe. It's more trouble than gain.

You said wall, hence the estimated height of 2m inside.

If you do this do a batch and bell wall. The same type of wall i showed you in the lopez lab link. I think it would be better.

2.63m3 of cob is huge. about 5 tons.

If you do this as wall, with the dimensions given,

You would have about 8m², of ISA with 20cm walls.

So 200mm batch rocket. You could increase the size of your bell a bit

There's one detail, which buggs me.  Your outside wall.

What is your plan? Do you really want to heat the greenhouse the same as the house, or you want less heat in there? Because, walls of a bell, of more than 20cm, take a lot of time to heat up. let say, 6 hours for a significant rise in temperature.

So if you want to heat the greenhouse, you shouldn't use a 60cm thick cob wall. It would heat up. Sure, have a temperating effect on the greenhouse. But would the greenhouse be like more than 2 or 3C° above ambient? I don't know.

Satamax Antone wrote:Augustin, don't do this with pipe. It's more trouble than gain. You said wall, hence the estimated height of 2m inside.
If you do this do a batch and bell wall. The same type of wall i showed you in the lopez lab link. I think it would be better.
2.63m3 of cob is huge. about 5 tons. If you do this as wall, with the dimensions given,
You would have about 8m², of ISA with 20cm walls. So 200mm batch rocket. You could increase the size of your bell a bit
There's one detail, which buggs me.  Your outside wall. What is your plan? Do you really want to heat the greenhouse the same as the house, or you want less heat in there? Because, walls of a bell, of more than 20cm, take a lot of time to heat up

I understand, after spending a nice amount of time reading several threads from donkey32, aswell as reading the investigation of these russian fellows and their free movement gas batch heaters, have totally convinced me. Ive always been a fact-boy and the data given there is pure gold.

From the information ive gathered, the 200mm batch would require 14.2kg of wood daily, producing an equivalent of 4.4 kW, with the fire being fed twice a day. Not only that i consider that to be alot of wood, but in comparison to these handful of sticks ive seen as j-tube load in videos, suposedly keeping it warm for an astonishing period of time, 14kg seems like a big amount of wood (ive never ever trully used wood as fuel since im from the most arid desert in the world and there is not the nearest need to fire anything but for cooking, which aint done by burning wood. Ill be moving to this "cold" southern region and soon to be my new home within the next 6 months)

Since the temperature rarely drops below 3 °C in the coldest hours of the year, Im considering the least optimistic scenario and give the avarage temperture a value of 5 °C. Following this formula, we'll determine the amount of energy required by the system:

Q = G*V*DT

insulation factor(G):
- 1.8 for an old, leaky, stone and clay mortar house (classical french farmhouses)
- 1.6 for a house in bricks, stones or breeze blocks without insulation
- 1.4 for a house insulated with 4 cm of polystyrene
- 1.2 for a house insulated with 10 cm of polystyrene
- 0.8 for a recent house with 37 cm thick insulating clay bricks for example
- 0.5 for a strawbale house for example

with G = 1.2, V = 115 m3 and DT = 15 °C, the equivalent loss of heat would be 2.07kW, being the 150mm batch the closest but underpowered by 5%, with a power disipation of 1.9kW, followed by the 175mm2 and its 2.9kW (45% overpower), continued by the proposed 200m and its 4.4kW (220% overpower). Dont get me wrong, im all hands up about oversizing the heater, as ive read, "the very important point is to always OVERSIZE the heater".

Some other data that ive gathered:

Recommended bell size is:
150 mm system, 5 m2
180 mm system, 7.15 m2
200 mm system, 8.85 m2

Lastly, im not entirely sure how to form the continuous line of bells in an horizontal array, also, how much impact has the uneven heating of the horizontal gas flow compared to the vertical, chimney-style batchbox? Id really like to add a smoker in it aswell? the russian fellows listed a big amount of useful equipment you can fit in the batch, like a water heating coil, different kinds of ovens, grills and more.

Ill attach an image of diferent variations in lenght of a detailed batch plane i was able to find, im not quite sure where are the bells in these schemes. (got the rest of the images in case somebody is interested)

Thanks so much for the help, i feel like all the information from the RMH prior to this batchbox new method belonged to the stone age :v

Augustin, i was advising to make a eight batch. But i was saying your bell was kind of sized right.

14kg of wood, is equivalent to 3 steres, or about one cord for the heating season. I'm very dubious one can heat with as little wood as this.

Well, the first thing, if you want to get the grasp, is to make a cooking J tube rocket.

Satamax Antone wrote:Augustin, i was advising to make a eight batch. But i was saying your bell was kind of sized right.
14kg of wood, is equivalent to 3 steres, or about one cord for the heating season. I'm very dubious one can heat with as little wood as this.
Well, the first thing, if you want to get the grasp, is to make a cooking J tube rocket.

Holy moly, why changing to the j-tube now?
Im really in for the batch box. When you say my bell size was right, you meant the 55 gal i chose for the initial j-tube RMH? Could you talk to me about horizontal bells array? Those long heaters from the last picture really catch my interest.

I was talking about building a temporary outside one. To get how a j tube works.

I'm not a fan of normal j tubes. They are a hassle to feed. Imho.

But i might have a simple solution for you. If you switch to bench.

http://s65.photobucket.com/user/mremine/library/NYC%20Rocket%20Stove%20Build/

Satamax Antone wrote:I was talking about building a temporary outside one. To get how a j tube works
I'm not a fan of normal j tubes. They are a hassle to feed.  
But i might have a simple solution for you. If you switch to bench.
http://s65.photobucket.com/user/mremine/library/NYC%20Rocket%20Stove%20Build/

Thanks for the refference, I wanna set cleat that my true goal is to be able to heat the greenhouse and livingroom altogether, but i certainly rather have a hotter greenhouse and colder living room, compared to a hotter living and a colder greenhouse  (if one of the two rooms temp will be compromised).

Second, i wanna build with the most effective method aswell as with the most cost-effective materials. Therefore, i dont care if the thing ends up with ANY shape, i only intend to make it fit inside the greenhouse at the ground lvl, and for it to be able to heat aswell a 30m2 area which will be at around 80cm lifetd from the ground

Ive watched that set of photos but cannot understand where are the bells placed, since i only can appreciate a long, wide pipe of barrels. I dont understand how that building is even better than a regular 8" j-tube RMH, since it has very big exhaust pipe and a small amount of mass. In addition it neither will be able to heat a half-raised floor since it only reaches 60cm height max.

Im very grateful for all your effort, mr Maximilien.

Most efficient, batch and Bell.

Is your house built?

Satamax Antone wrote:Most efficient, batch and Bell.
Is your house built?

Its not, above is the current scketch made by me, a non-proffesional.
I want the house to be floor-lifted aswell as having a lean-on chinese greenhouse.

Ok, the best advice i can give, is if you want to heat the greenhouse as well as the living room. Make your bell an integral part of the wall. If you can afford a double layer of firebricks and normal bricks. On such a big surface.

I think i understand vaguely, you want the long and tallish bell for starting your seedlings on a table?

Anyway, the dimensions you gave are suited to an eight inch batch approximately.

If i had to do this, i would go along this route.

http://batchrocket.eu/en/applications#culdesac

Single bench, of twice the height, or more, and the smaller possible bell, for it to work. You could make your outside wall solid mass. Don't use hollow blocks, as they conduct the heat weirdly. And don't have so much mass. And line it with firebricks splits on the inside.

You could also, make a door opening, where the tall bell would be, and build the bell in the doorway, so it's outside surface is in the greenhouse. This could be an idea too.

Remember, the thicker the wall, the longer heat takes to reach the outside. In mine, 220mm batch 20cm thick wall. . It takes 6 hours to really notice it. Peak is about 8 to 10 hours later. So if you burn around 5 pm to 8 pm, your peak would be between 3am and 5am. Quite a good time, as this is when the coldest time of day happens.

You could also, make the wall of the bell towards the house thinner, to provide more wamth at better times for your comfort.

Here's a few ideas.

Originally the COB wall was going to be a bench at the living room, as it would raise from the ground level up into a 80cm lifted-floor, plus another 60 cms to make it a bench, i decided to call it a "wall", because of its dimentions but not fuction, therefore, i conclude that the term has very been poorly chosen.

The size of the exhaust, for example, your 10" batchbox, where does it exactly measures 10"? These boxes seem to have no pipes, so where does that number generates :O?

I believe ill yes/yes follow the way of mr Van Der Berg or the style from the russian mass heaters.

What about something like this? Which size would you say that monster is? 8-10-12" or what?

The gadgets as ovens or others are not a requiremnt at all, i just want a warm greenhouse as well as a benefited living room due the trick im intending to do.

Augustin, the size is relative to the heat riser diameter, otherwise called system size.

So this russian stove hasn't a size. But by firebox's size, you could consider it a 10 or so. If it is single bell, it would be a bit small for a 10 bell wise.

I understand, which display of bricks would be better for this purpose? I would imagine that something in a "wall" shape, :P here we go again, lol.

I have updated the pictures from the original post aswell. Im thinking about one of these square beasts, but narrower and longer?

What do the rest of the forum think? :v

Thanks so much for your patience and good intentions, ive learned oh so much already with all the guidance youve provided to me

Augustin, postwise, it's better to make a new post, quoting your first one, and showing the differences, rather than editing an old post, which might mess the thread up. Hth.

Max.

Satamax Antone wrote:Augustin, postwise, it's better to make a new post, quoting your first one, and showing the differences, rather than editing an old post, which might mess the thread up. Hth.
Max.

I too think so, but in the other hand the post never had much to do wilth RMH wall since your pretty much the only one giving corrections jojojoj, so nearly all of the replies talk about a BBMH.

Which display of bricks would be better for this purpose? I would imagine that something in a "wall" shape would transfer heat more efficiently to 2 rooms, rathen than a huge box, since neither the lateral sides nor the bottom face of the boxes will be in direct contact with neither of the rooms. Only the front, rear and top face will be facing one of the two rooms. I fact, only like the 65% of ther rear face will be in direct contact with the living rooms area, since the missing % is below the lifted-floor level. In compensation for the missing area of contact of the wall inside the house, the majority of top face of the BBMH will in direct contact with the livingroom aswell.

How many bells would be appropiate?

How many vertical bells would be the best?

Can you place the other bells in an horizontal array if the main and second chamber are stacked vertically?

Can you place for example, a row of 2 bells stacked vertically? like 4 to 10 bells stacked by two, resulting in 2 to 5 columns of 2 vertically stacked bells.

How much is the exhaust draft. aswell as heating distribution and other impactful factor, modified by utilizing two kind of arrays of bells orientation?

How accuratedly will the temperture of the desired gadget (cookstove, oven, smoker, water coil, etc) match the temperature of the bell you place it in? For example, if i wanna install a smoker, i would think that the main bell and maybe the second are far too hot for the purpose but maybe the later bellls would be too cold.


Thanks so so so much for all the help