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Open source cellulose insulation manufacturing
| By Michigan Tech's Open Sustainability Technology Lab.
Wanted: Students to make a distributed future with solar-powered open-source 3-D printing.
|The competition for inspiration|
The goal of this project is to create an open source cellulose insulation manufacturing machine for the goal of local production of cellulose insulation from post consumer paper waste. Local manufacturing would reduce embodied energy of transportation and provide a valuable product from local waste streams - particularly in cold climates like the UP!
The machine will process post-consumer paper sourced locally to create the 75-85% recycled paper fiber and then mix it with the other 15%-25% of a fire retardant such as boric acid.
Cellulose Insulation is one of the greenest products in the world as it both saves energy by conserving heat in buildings and it is made from recycled paper (newsprint and other paper sources), paper that might otherwise end up in landfills, releasing greenhouse gases as it decomposed.
- Lowest embodied energy of any insulation (fiberglass is 10X as much, foam 60X) 
- Green building material for LEED
- sound proofing, insulation, and fire retardation.
- Works best at high deltaT form indoor and outdoor
Basic design specs
- ability to shred paper to 5cm add borate then "fiberize" to 4mm
Does this make sense?
- Search on internet found several sources for boric acid
- $1/lb for granules  or for the powder - slightly less (44 if 100+ sacks) if you buy many 50lb sacks.
- if assume the electricity, labor and the paper is free that means you are paying ~$0.25/lb for insulation
- Cellulose insulation - 23lb bag for $7.20 or $0.31/lb 
- Cellulose insulation - 1050LBS for $420 is $0.40/lb 
- Cellulose insulation - 17280lbs for $6393 is $0.37/lb 
This gives you a 20% savings on materials - but your time and the electricity and the machine are all going to have real costs. However, the disposal of the paper will have a real cost too. This looks marginal. So for 1000 square feet of attic in the UP you would want R60 and need 105 standard bags of 19.05lbs/bag or ~2000lbs  with possible savings of 6 cents/lb = $120 on a $620 purchase
- Where does 15-25% boric acid figure come from?
- What are substitutes for boric acid?
- Is flame retardant needed in nonflammable walls, such as with Compressed Earth Block?
- Life Cycle Analysis of a Residential Home in Michigan” S. Blanchard & P. Reppe (Sept. 1998); Canadian Architect Measures of Sustainability -- check me. http://www.canadianarchitect.com/asf/perspectives_sustainibility/measures_of_sustainablity/measures_of_sustainablity_embodied.htm