Rocket mass heater build (time for a rocket stove subform?)

Looking at the front of the stove, the flue exits the bench and goes left along the floor then turns up to a hole in the flue 6 1/2' feet up the wall to the left of the stove, behind the natural gas furnace.

When TurboDiesel and I were teenagers our dad had a Buderus wood and coal boiler in the same spot that preheated the water for the baseboard hot water heat system. When it was burning the natural gas furnace never kicked on. It's a heavy duty lined modern chimney.

 

Post #6, bottom pic, right side, stove pipe near floor turns up next to wall and turns right at flue connection about 7 feet high

 

Boiler

 

Yep, the multiple flues in the chimney are in the center of the house, the wall on the far right of the alcove where the bench is located is an outside wall.

 

You're the plumber/HVAC guy in the family, I'm just a dumb doctor. Whadda I know?

 

And to throw a curve...I bought a 6'x11'x4' deep soft sided/portable therapy pool off Craigslist this fall for my rehab and exercise after strokes.

I'll run the water from the pool via 3/4" cpvc and a 12v circulator pump to the stove bench, where it will circulate through 100' of copper tubing coils in the top of the bench, then back to the pool. It's an open system so no fear of a steam explosion.

That will serve two purposes, 1) the obvious one of heating the therapy pool with wood, and 2) the 2500 gallons of 86 degree pool water will serve as another heat sink, 30' away from the rocket stove, slowly and gently but definitely heating the rest of the house.

I know it will work because when the kids were small I put a 10'x15' oval above ground pool in my (old wet) basement for fun and exercise. (My kids could honestly say they swam in their own pool in the dead of winter!)

We got a heat pump pool heater from a 28' round above ground pool off Craigslist and kept the pool 86-90*.

The electricity we burned to run that heat pump was far outweighed by the natural gas we saved heating the house at the time. The house was never so comfortable as it was with that giant heat sink in the basement. We controlled humidity by keeping it covered with a cheap solar cover.

 

Outside! Sorry, couldn't resist

Awesome job Brian! Very impressive design, I can tell lots of thought went into this...and I'm loving the use of all the fairly commonly available and affordable materials! Keep it coming...on the edge of my "bench" here

 

I hate that common current "state of the art" plans for rocket stoves call for mixing up multiple wheel barrow loads of cob (a mixture of clay, sand, straw, sometimes dirt and water), or clay and water and vermiculite, to build the firebox, riser and bench/bell. I specifically wanted to create a design that uses no cob or mortar, just Craigslist finds and hand tools.

Except the ceramic stuff. But these vacuum formed ceramic fiber risers only cost $36 a piece. $75 for the ceramic fiber boards, $37 for a 1" thick roll of 2'x24' white ceramic blanket insulation, all from a company in Pittsburgh that supplies the steel industry. A $5 80lb bag of concrete, $75 for the barrel stove off Craigslist, which came with 14' of stove pipe and a couple elbows and a damper, and $40 worth of 75 cent 18"x9"x4.5" firebrick. (Since we're lining the firebox with ceramic fiber board, you could probably just use cement building blocks.)

I spent more acquiring tools and various hardware than I did on the basics for the stove.

 

I'll be finishing the bench and the plumbing this weekend, and then the first fire. These things like small loosely packed wood as fuel. I found about a cord worth of 3"x 1/2" pine boards in the rafters above our garage that's been up there for 60 years since the previous owners built the house. Perfect fuel!

 

Is Daryl still around? I think she would enjoy this build.

 

This is an impressive project for a guy who had multiple strokes. Heck, just the write up is a lot of work.
Sure hope that pool isn't prone to leaks...that would be miserable.

 

Good to "see" you! Thanks. (I needed a project to get my brain off all the problems in the world and the Church for a while! And unfortunately this project already involved one trip to the ER when I thought I broke my wrist after falling on the outside cement basement stairs while moving firebrick.)

It's a pretty reliable design, with an inside vinyl pool liner and an outside liner made of the same material the military uses for Kodiak type inflatable boats. I did a lot of research on this prior to finding a used one; it's not a cheap Chinese back yard soft sided Intex pool.

 

My bench is almost done. Now I need to plumb the copper tubing coils in the top of the bench, and then...first fire! The 2'x2' pavers were 50lbs each, so with a double layer of them on top this bench will constitute ~3000lbs of mass.

 

TurboDiesel was going to help me plumb the copper tubing and coils in the bench last night but was sick all weekend and is working out of town all week.

Being the impatient and foolish man I am, I watched several YouTube videos and I'm trying my hand at sweating copper tonight.

How hard could it be? And ... how do you know it was done right without hooking it up to check for water leaks?

 

I'll hook up the pump tomorrow and check for leaks.

 

Wow that looks like a sweet setup! I like it. How much time and money do you think you'll have in it?

 

A lot of time, primarily because I'm still recovering from strokes and only working on it intermittently and at a snails pace.

I've been collecting all this stuff for years in anticipation of this build.

These vacuum formed ceramic fiber risers only cost $36 a piece, $75 for the low density ceramic fiber boards, $37 for a 1" thick roll of 2'x24' white ceramic blanket insulation, all from a company in Pittsburgh that supplies the steel industry.

A $5 80lb bag of concrete, $75 for the barrel stove off Craigslist, which came with 14' of stove pipe and a couple elbows and a damper, and $40 worth of 75 cent 18"x9"x4.5" firebricks. Various pieces of additional stove pipe and 2 clean out Ts (but I'm not sure what I spent on those). A 6" bimetallic hole saw was $70 but worth every penny, and a crimping tool from Lowes was $16. I've had the barrel several years now (free) and I've had the 2'x2' pavers (free, from my old office) for 20 years. (My wife always wondered what I was keeping those for. Now I know!) Various cpvc and copper tubing (Craigslist) and copper and cpvc fittings for the plumbing. A $32 12v pump from Harbor Freight.


I spent a bit acquiring tools and various hardware too.

 

Thanks for the info it looks very cool. I hope it works as good as it looks! I will pray for a speedy and full recovery for you!
You'll have to post a video of this beast in action! I'll be looking forward to it.

 

You could use air pressure or a co2 extingusher to check for leaks . just remember to only heat the female portion of the copper connections and wipe the solder all the way around a couple times. Also a good idea afterwards to wipe off & nutralize the acid flux .

 

Very cool, I've just been checking into small "rocket stoves" and this is perfect timing along with someone's link to EricVW' thread. Gotta read this again & slower
You Pittsburg source for some of those materials, do they have a web site?