Biomeiler (compost Heater)???

Does anyone have experience setting up a radiant heat system using Jean Pain's compost heater design? I'm crazy interested in this and I'm at that stage where greenhouse hoops are going up.

I'd like to integrate it if it's feasible. Here are some links for what I've found already:

My main concern is how large of a compost pile I would need to provide enough heat for 12 months. I have two 30ftx36ft Greenhouses that are 17ft tall at the peak. I'm thinking of a radiant heated floor... pump water through tubes that run in coils in the compost piles and then out through the greenhouse floors.