permaculture

[Neil Bertrando <neilbertrando@gmail.com>]

Hi all,

I have another request for information, anecdotes, experiences, and
suggestions.

I'm working with a group to develop an aquaponics system in a tunnel house
in a hot-cold drylands climate, and as part of our thermoregulation
strategy, we'd like to combine the jean pain compost heat exchanger with a
hydronic radiant floor heating system.

Does anyone have experience with something like this?  My understanding is
that Jean Pain used steam or water radiators which hopefully are similar.

To start we'll just be using the compost heat exchanger and not the methane
digester part of Jean Pain's system.

Some concerns that have been raised by the group are:

1. that the hydronic radiant heat system will 'suck' too much heat out of
the pile and cause it to lose it's thermophilic properties and therefore
it's function.

2. that a compost pile cannot create enough BTUs to heat the water.

I would love to hear stories from people who have done anything similar.
Especially with specs re: flow rate, system volume, BTUs transferred,
compost pile size, regulating a delta-T, duration of heating action per
pile, preferred pipe for the compost heat exchanger, maintenance, return on
investment, quirks or unexpected phenomena, etc.

Our goal with this system is to offset the need for heating by some other
method (propane, biogas, electricity, etc.), not to completely heat the
greenhouse through the winter months.

I am very interested in beta testing this system because I hope to install
one in my house as part of a hybrid heating-cooling system.

It seems to me that the hydronic radiant heating can be hybridized with
compost thermal, solar thermal, wood stove, biogas, geothermal, propane
(backup) and hopefully more.

I would prefer all passive solar buildings to start, but with 'the Great
Retrofit' in mind, I'm open to options and ideas.  Any thoughts specific to
long-term viability or transition technology aspects of these applications,
would be appreciated as well.

I've looked into the compost heated greenhouses that the New Alchemy
Institute worked on, and I hope that using the Jean Pain method addresses
some of the difficulties they ran into with toxic buildup of gasses (CO2,
CH4, and NH3 i think) by locating the pile outside the building.

I'm happy to address questions about specifics on this list as well if
people are interested.

cheers,
Neil
Reno, NV, USA