will marconi

Hi all its been a while as i have been away for work. i am going to be starting this build soon. I am finalizing my plan.

I am looking for some insight on proper sizing/ volume of the bell compartment for a 7" system.

I am building a large water storage tank as my thermal mass the bottom of the tank will be the top of the bell compartment. I been working all the math to figure the right sizing of things for my system. However, I still lack the information on proper sizing of the bell area. As of now the plan for the tank is 4' in diameter and 4' tall. So there will be a 4' diamter surface area to act as a heat exchanger at the top of the bell. How tall should the bell be, to get the maximum heat exchange before exhaust? I am not limited to this size tank.

Thank you for all the great information.

Will

Hi all its been a while as i have been away for work. So i am going to be starting this soon. I am finalizing my plan.

I am looking for some insight on proper sizing/ volume of the bell compartment for a 7" system.

I am building a large water storage tank as my thermal mass the bottom of the tank will be the top of the bell compartment. I been working all the math to figure the right sizing of things for my system. However, I still lack the information on proper sizing of the bell area. As of now the plan for the tank is 4' in diameter and 4' tall. So there will be a 4' diamter surface area to act as a heat exchanger at the top of the bell. How tall should the bell be, to get the maximum heat exchange before exhaust? I am not limited to this size tank.

Thank you for all the great information.

Will

all good information.. does the 8" batch box system have a longer burn time compared to the 6"? or does it put more BTUs in thermal storage faster?

I like the idea of over sizing but controlling the output with smaller loads. Great idea. Also will slow me to keep cutting 20 inch long logs or so. That's what I am used to cutting.

does anyone see a problem with too small of a batch in an 8 inch system? filling it a quater full. Like not draw properly? My thoughts are over size and be aware of out side temps for amount of wood to put in batch.

I have read that people prime there system by lighting a peice of news paper in the exaust. I was thinking of installing a blower fan on the end of a T where the exaust meets the wall and wire it to a switch. Turn it in when trying to light. Any one try this?

Will

anyone know roughly how many pounds of wood fit in the 6" and the 8" batch box. I am working on figuring how much btu storage I need, and proper sizing.

thanks for all help

will

lots of information to digest. I am studying it. very cool! I wanted to put in a glass door anyway. I am working on my house load. Using the numbers you shared with me, and what has been currently working. Surely the rockets will be more efficient. I would be most happy to reduce my wood consumption. This is a link to my current furnace.

http://www.usstove.com/index.php?route=product/product&path=125&product_id=977

I drilled it and installed water coils for (2) 50 gallon propane water tanks as storage. On a typical 20 degree day I burned about (9) pieces of hardwood about 20" length 7" diameter. I would burn about 12 hours a day. When first lit I run wide open an hour, once its well lit I would damp it down the rest of the day. the hot water keeps house evenly distributed and warm at night when not burning.

I really like this batch box idea. Do you have any thoughts on running an external air intake from the outside? I am thing with this refractory cement I could mold a hole in for a pipe at the bottom instead of door. I can hear the difference in a exhaust fan when the outside door is opened. Also I crack the door when starting the fire as it helps get things rolling. less smoke etc. Thoughts?

Do you prefer the bricks over cast refractory? longest life? either way I will build it so I can replace easy.

Thank you for the reply and information Doug. I am thinking of making the heater out of fire brick and using the common J shape rocket. I am still digesting the chart you pointed me too and how to it incorperate it in my design.

Do you have any kind size chart for a 10" exaust for in terms of J shape fire brick rocket? Specifically the feeder, burn tunnel, and riser?

On your sugested chart what is the "base" demension? Would that be the burn tunnel? thanks for your time.

hello all,

I live in WV and built my own off grid home. I am striving for self sufficient farm.

r 25 wall, r 60 or better in ceilings. The wall insulation is closed cell spray foam as it is a good wind barrier. 3100 sqft. 3 floors total. 2 floors 36x36 and a 3rd floor centered 16x36. Unlike most down the rabbit hole, I don't agree with a small home. There are many universal household tasks that are not scalable. I believe as times get harder more family and friends will need help, so I am setup.

I found you guys. I believe in the rocket mass heater concept, I have bought the rocket mass heater 3rd edition book and using it as a reference. Currently I have a wood furnace with water coils connected to propane hot water tanks as thermal storage/dual boiler option, with a pex hydronic distribution system. Everything works great.

Winters can be harsh. I currently burn 3/4 to 1 cord a month. About 4-5 a winter. My chimney exhausts the house at head height at bottom floor. I have a long 6" double wall insulated pipe running up past the eve.

So, by reading your design and accomplishments you all convinced me that I am wasting many btu's maintaining high exhaust temps. Now coming out of winter I am selling my furnace and insulated pipe. I am convinced I can get more efficient and burn less wood.

The hole in first floor at the wall "can" accommodate an 8" exhaust pipe. I could make it bigger, but that would be a project as its a concrete wall.

I plan on welding a custom stainless steel water tank as my thermal mass, and using it as a heat exchanger to my current propane hot water tank system.

Currently I am planning on your 8" system using all brick with a metal cooktop/clean out instead of 55 gallon barrel. (putting more heat to the exhaust/mass section)

Quality and life of the stove is most important to me.

1. is 8" big enough or should I go 10"?
2. if I go 10" system do you think I can reduce to 8" "at the wall" on the exhaust? assuming I serpentine enough to exhaust at cold temps where the air volume would be reduced due to lower temperatures. I am thinking 35'
3. if I use 10 system what dimensions do you recommend for the feed tube, burn tunnel, heat riser, length of exhaust?
3. thoughts, comments, questions?

I think this is great site. if anyone needs solar, wind, off grid living advice email me I would be glad to help. wdmarconi@yahoo.com