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Cast Batch Box Rocket Mass Heater using LTGS  RSS feed

 
Posts: 22
Location: Kansas City, Missouri, United States
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I am currently planning to build a Cast Batch Box rocket mass heater (RMH) using Low-Temperature Geopolymer Setting (LTGS). 

I've built a working J-Tube RMH out of LTGS in order to test the techniques and materials.  So far so good.  I will attach pics of all the items mentioned in this post as replies to the post. 

My primary sources of information in this endeavor are:
- this website
- Erica and Ernie Wisner's book "The rocket mass heater Builder's Guide"
- Peter van den Berg's web site:  http://batchrocket.eu/en/
- the LTGS website I was using is no longer available.

The primary design components are as follows:
- 6" Chimney and overall system
- The batch box will be 7 cast parts: (Floor, Right side, Left side, Back wall which includes the front bottom portion of the heat riser, Back bottom heat riser, Front top heat riser and Back top heat riser)
- I will use 5 forms to cast the batch box and heat riser (2 are reusable)
- Bell will be 3 layers with a 1/4" steel "lid" on top.  The layers consist of 1 1/4" LTGS on the inside, 4" concrete bricks outside of that and a decorative stone veneer
- the Batch box will be raised off the floor 9"
- the Bell will be 13.5" x 13.5" x 67.4"
- the Bell ISA computes to 25.6 cu ft
- the Heat exchange will be a total of 8' long with 3 turns
- the Heat exchange ISA computes to 31.4 cu ft
- for a Total ISA of 57.0 cu ft .1 under the target ISA of 57.1 cu ft
- there is 2 3/4" clearance on each side of the heat riser inside the bell giving a 185 sq in CSA.  This gives a 6.6/1 ratio exceeding the 5.0/1 requirement.
- a 1 1/2 story class "A" chimney will be installed inside the house through the ceiling and the roof.
- approximately 5 cu ft of LTGS will be needed at a cost of about $200 total (not including the J-tube prototype)

My questions:
1 - Will the LTGS use within the bell inhibit the system "draw"?
2 - Am I missing anything else?





 
Steve Shelton
Posts: 22
Location: Kansas City, Missouri, United States
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My J-tube Cast LTGS RMH uses the 1 - 2 - 4 structural ratio target

It was poured using a single mold.  The burn tunnel was formed with wood and wood-glue and was designed to "burn out" upon first use.

It fired and drew appropriately.

The external temperature of the 1 1/2 inch thick LTGS was around 100 degrees F

The internal temperature exceeded the 500-degree max temperature of my infrared thermometer.  So it was "Really HOT!"

Note: I did not add enough water to the LTGS mixture.  This prevented it from settling properly.  I have adjusted my LTGS recipe to correct the issue.

2017-10-21-09.19.06.jpg
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Steve Shelton
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Location: Kansas City, Missouri, United States
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Here are some snaps from my Batch RMH Sketchup
Final-Mass-RMH.jpg
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Batch-RMH-Front-View.jpg
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Batch-RMH-Top-view.jpg
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Steve Shelton
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Location: Kansas City, Missouri, United States
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Here's a pic of the form used to build the J-Tube

J-Tube-Form.jpg
[Thumbnail for J-Tube-Form.jpg]
 
Posts: 39
Location: North Alabama
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Thanks for sharing Steve. I really like the direction you're headed. Please keep us updated as you install and learn to run it.
 
Steve Shelton
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Location: Kansas City, Missouri, United States
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Cast Batch Box Rocket Heater
 
Steve Shelton
Posts: 22
Location: Kansas City, Missouri, United States
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15g of rock wool after it was run through a kitchen blender
Rock-Wool-15g.jpg
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Steve Shelton
Posts: 22
Location: Kansas City, Missouri, United States
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Here is the latest and hopefully last pic of my target Batch Box rocket mass heater.  My intent is to:
- build an aesthetically pleasing heater
- add value to my home
- add an alternative heat source (wood)
- utilize a renewable energy source (wood, many don't consider this in their definition of renewable but I do)
- efficiently convert the wood to heat
- efficiently distribute the heat to the entire house
RMH-Walls.jpg
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Steve Shelton
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Location: Kansas City, Missouri, United States
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Geopolymer cuts easily with a hand saw
2018-02-13-08.40.27.jpg
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Steve Shelton
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Location: Kansas City, Missouri, United States
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I am exploring another Batch Box design.  It is known as the Double Shoebox Rocket (DSR).  I will be experimenting with this idea for the next few months.  It utilizes many of the same modular components as the BBR.  Therefore, if I need to revert back to the original design, I can do so with little waste.
DSR-Top-View.jpg
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DSR-Front-View.jpg
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Steve Shelton
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Location: Kansas City, Missouri, United States
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Latest sample of LTGS
IMG_20180220_121923.jpg
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Steve Shelton
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Location: Kansas City, Missouri, United States
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Bell
DSR-Bell.jpg
[Thumbnail for DSR-Bell.jpg]
 
Steve Shelton
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Location: Kansas City, Missouri, United States
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End result look
RMH-Walls.jpg
[Thumbnail for RMH-Walls.jpg]
 
Steve Shelton
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Location: Kansas City, Missouri, United States
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Plumbers Torch Test after 10 mins
IMG_20180222_145341.jpg
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IMG_20180222_150451.jpg
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Steve Shelton
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Location: Kansas City, Missouri, United States
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Here are the results of the temperature testing using a geopolymer piece 7/8" thick.

Geopolymer-Temp-Test.jpg
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Steve Shelton
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Location: Kansas City, Missouri, United States
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The first form is poured for the DSR.  It's inside the curing box.  Temps currently 102F on a hazy 80F spring day.

DSR-Backs-1st-form-pour.jpg
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Steve Shelton
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Location: Kansas City, Missouri, United States
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This is a view of the "Internal" components.  This comprises the actual DSR and Bell. 

DSR-Internal-View.jpg
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Steve Shelton
Posts: 22
Location: Kansas City, Missouri, United States
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The next 3 forms are ready to go.  I've adjusted the allowance for shrinkage to 11% after reviewing the first poured form's results.

Left to right they are:  Batch Box side, Batch Box floor (cut in 2), Batch Box and Shoe Box roofs (cut in 2)

2018-04-20-14.49.01.jpg
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Steve Shelton
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Location: Kansas City, Missouri, United States
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6 forms have been poured so far.  At this time there haven't been any visible cracks.  :)

IMG_20180430_160823.jpg
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pollinator
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Location: Ashhurst New Zealand
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Looks promising. What is the LTGS recipe, and how sensitive is it to local material composition?
 
Steve Shelton
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Location: Kansas City, Missouri, United States
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Phil Stevens wrote:Looks promising. What is the LTGS recipe, and how sensitive is it to local material composition?



You can read all about it here.

http://donkey32.proboards.com/thread/3283/geopolymer-code-named-kansas-city?page=1&scrollTo=29144
 
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