Indoor/Outdoor Rocket Mass Heater

I live in a small run down house in rural East Texas. Generally it gets in in the low 20's a couple of weeks a winter. Last winter it was worse The house has shiplap siding with no insulation. Ideally I want to build small house that is well insltated. That won't happen this year.

I have been trying to figure out a way to use a RMH but there is simply no place to put it. I also think a fire in the the houseis a bad idea since mother is completely blind and prone to falling. I have considered boiling water and pumping water through heat exchangers inside the house. Everything I read suggest this a bad idea and I don't think I heat that much water.

My last thought is to building a small structure ouside. Insulate it very well and add a generous amount of thermal mass - cobb or two or three 275 gallon IBC's full of water. Add a blower and a piece two metal ducts to the house and for return air. I would like to put the woodfeed outside of the structure for draft reasons and to stop a huge heat loss everytime it was time to add wood.

Richard, a kachelofen wouldn't work for you?

https://www.google.fr/search?q=kachelofen&safe=off&rlz=1T4SAVJ_enFR550FR551&prmd=ivns&tbm=isch&tbo=u&source=univ&sa=X&ved=0CB4QsARqFQoTCN-j6fHj2scCFYQIGgodn10OFA

They can be made with J or batch rocket. The tall traditional type doesn't take much room.

Thanks for the reply. I looked through alot pictures and found some that were small enough (about the size of a very large water heater) but they look to be fireplaces. I didn't really get how you adapt them to a j tube. Google was translating the pages and I think I was missing something in the translation. Are there any plans around of something like this? My degree was in drafting and design so plans or sketches would probably make more sense than photos.

Richard

The easiest thing would be to search here and on the http://www.donkey32.proboards.com forums for bell rocket mass heater. The bell principle is simple, build the J-tube or batch box with riser as usual, and have the riser inside a masonry box that is as tall as practical and at least 4 times the interior cross section area (subtracting the riser bulk) as the system size. This allows the hot gases to rise to the top and give off their heat, whle the cooler gases sink to the bottom and go to the chimney opening at floor level. You could make an 8" system with 8" thick walls (lots of mass) at 36" x 36" plus a bumpout on one side for the feed. This would only need modest clearances to walls etc.

Ahhh the joys of orthogonal projection etc!

Well, myself, i'd advise against the J tube. To me they're just a chore. I much prefer the batch rocket. Also called rocket 177, invented by Donkey and Canyon, and refined to the extreme by Peter Van Den Berg.

Here's two Dutch ones, which are quite nice and simple.

http://batchrocket.hostoi.com/html/foto.html

http://technologieforum.forumatic.com/viewtopic.php?f=19&t=27

Here's another one by Robert in Poland.

http://donkey32.proboards.com/thread/1464/rocket-kachel-ofen?page=1

As long as you respect few rules for the core and the heat extraction and storage, you can make one with pretty much anything fireproof and with the looks you want

I realy like the looks of this one.

http://donkey32.proboards.com/thread/1330/story-bells-20cm-batch-proposal#page=3

And for dimensions

http://donkey32.proboards.com/thread/734/peterberg-batch-box-dimensions

The "fireplace" look is deceiving; even the traditional kachelofen has an enclosed firebox which is designed for high-temperature combustion. The batch RMH with bell has a precisely designed firebox married to a riser which can improve significantly on traditional designs. It may not be visibly better, but it has been measured to be about as efficient and clean as physically possible.

I appreciate the replies but I don't think that that type of stove will work. All the drawings show a footer poured in the ground. I really don't see how I can crawl under the house and block and header off the floor joist and cut a hole in the floor. Not to mention carry concrete in to pour the footing. Also a 3 foot square stove with 1.5' clearances becomes a 6 foot square stove.

Richard

Richard Watkins : What kind of Furnace or wood stove are you using now ! Can you find a manufactures rating
Plate ? It should give a Model and Serial number and a Btu's Rating ! If this is a Fossil Fuel Fired Furnace it is actually
liable to be more accurate than a rating plate on a Wood stove unless the rating plate is Certified by the E.P.A.

For your location (texas) a J-Bend style Rocket Mass Heater RMH would need to be monitored/ fired over 3-4 hours
to give you 24 -48 hours of heat stored within your thermal mass

A Batch Box Rocket Is a load and forget operation but again can eliminate the need for attention by your mother
while still providing 24-48 hours with 1- 3 firing a day !

Trying to run an RMH from, or in a remote location quickly turns into a chore that no one does well.

Most people who have tried to make an outdoor operated RMH discover that they are spending more time and
losing more heat not less !

Trusting U-Tube videos is a lot like Card playing Three or more of a set of videos show ing construction and serial
operation of that RMH is worth a lot more than just one look what i just did- The Absence of any follow up videos
that show how the RMH works over time generally means that that Builder has found a flaw in his build and no
longer is posting updates -he is off chasing the next shine-y Babble !

A little more information on your present heating system and your houses layout will help us give you useful answers

If there is a Rocket in your future we want to help you build it ! For the Good of the Craft Big AL

Richard, do you have an old fireplace in that house?

We use two electric heaters. I think they are ceramic type and are rated at 1500 watts. I am not sure how that equates to BTUs. They are zero clearance. No part is hot. Forced air and you wold have to hold your hand on the oulet for a while to get burned. One big problem with the heaters is there operating cost. The electric bill was around $400 a month. It got as cold as the mid 40's several times this past winter. Usually happens when have a cold night (low 20's) and then the sun doesn't come out the next day and it stays below 40. The heaters run all day and the temperature never recovers.

There is a fireplace with an insert. It never heated the room it is in very well and burned a lot wood ever day. Had to feed it a couple or more times during the night the temperature would get low enough for the blower to shut down. It uses a catalitic converter that seemed to wear out in one or two seasons. It is fairly expensive to replace. We only burned seasoned oak.

BTW, I don't trust vry much on YouTube useless I find a lot of other sites and/or books that agree. I have found that you can watch 6 videos on the same subject and find at least twice that many descrepences. Most are small but some are huge.

Richard

Richard, can you post pictures of your fireplace and hearth?

Thanks.

If your fireplace is decent sized and solid masonry, you can probably build a RMH in and in front of it that can heat your house, without taking up much more space than the fireplace clearance requires already. Bonus if it is on an inside wall. If the chimney is still safe for the insert to operate, it should be safe for the RMH. What size and material is the flue, and how tall is it?

In some ways this is an ideal conversion situation, as a fireplace will generally be situated to at least look like it warms its room already, and have decent clearances. If the hearth is substantial, it may be able to support an RMH without further foundation work, which in a crawlspace is not difficult anyway. The heating load you describe sounds like a 6" batch box with minimal sized bell would be able to handle it easily, maybe at as little as 20" x 36" built tight to the fireplace, maybe even less if the fireplace is big enough to fit the riser inside.

I cannot put the heater in that room.