Heat from Composting Biomass

I've been collecting material on the idea of extracting heat from compost piles and adding it to this section...

At first, this was a "that's kind of interesting" idea to me, but it has become more and more of a "that might really work" sort of idea.

Basically these schemes (there are several shown) start with a carefully constructed, large pile of biomass.  The biomass heats up as it goes through the composting process.  Pipes running through the pile pick up heat which can be used for domestic water heating and/or space heating.  Some schemes simultaneously collect bio-gas, which can be used for cooking fuel or even running a vehicle or generator.


Marc's compost furnace under construction.

A lot of work was done on this in the 70's by Jean Pain in France.  The section has some good descriptions of Pain's work, including two newly added videos (thanks to Curbie for these).

Marc's compost furnace work is very interesting, and includes some results from his first winter of operation.

The MB-Soft work in this area is interesting, if a little hard to decipher.

The New Alchemy papers are also quite good.

The attraction of this approach to me is that it holds the promise of a carbon neutral way of generating useful amounts of heat over long periods of time.  Some of the Pain piles are said to have been still generating useful heat after 18 months.  It is quite a bit of work to build one of the structured compost piles and set up the heat extraction plumbing, but then you may be able to get useful heating from the pile for an entire heating season.
The efficiency is claimed to be of the same order as burning the biomass -- maybe even a little better.  In many cases, the biomass can be material that would just be left to rot in place.

Does anyone have more useful information on this area?
Any thoughts on how useful and idea this might be?

Gary

Some New Content Items for Build-It-Solar

Three New Content Items

1. Lee's Solar Mower
Some time back, Lee sent in the details for his solar lawn mower.  The article basically tells you how to convert a gasoline powered mower to a battery powered electric mower with solar charging.
One issue with doing this is finding a good electric motor.  The one that Lee originally used is no longer available.  So, Lee has found a new source of motors that should work well and are cheap and easy to find....



2. Performance Update for Marc's  Compost Furnace

Last week, Marc provided a description of his system to provide space heating via heat extracted from a compost pile.
Marc has provided some performance data and other observations based on the first full season of operation...


3. A Home Built Grid-Tied PV System with Battery Backup
A
detailed account of the design and installation of a grid-tied PV system
with battery backup.

A home built ground mount system from treated lumber
is also described.

A well designed compost furnace for space/water heating

Marc has worked out a what appears to be a very nice design for extracting heat from a large compost pile for space heating.



Marc's design includes a blower and air supply manifold system to aerate the pile, a pipe network to add water to the pile as needed, a pipe network to extract heat from the pile, insulation to increase the efficiency of the composting process, and a nice containment and cover system.

Link to Marc's blog entry on heat from compost...

Other heat from compost schemes on Build-It-Solar...

Judging from the emails I get, there is a lot of interest in using compost to generate heat, but there is not a lot of detailed information out there on how to actually build such as system.  I think Marc has taken a good cut at it.  What do you think?

Gary