The Compost Heat Exchanger Project

Our project is the design and construction of a compost heat exchanger that will heat a rainwater storage tank within the greenhouse at the Radix Center in Albany.  At the most basic form, the heat exchanger is a compost pile built from bark mulch, wood chips, and manure that has a polyethylene hose transporting water throughout.  Cold water is pumped into the pile and the effluent water is hot due to heat exchange between the compost pile and the water within the hose.  The heat is the result of bacteria aerobically breaking down the carbon and the nitrogen in the compost pile.  This is a sustainable way to heat water, as it has minimal energy inputs and the only waste product is fresh, usable soil.