Studying Sustainable Energy Solutions: Gaelan Brown’s Compost-Powered Heat

There is enough snow on the ground, looking at Gaelan Brown’s compost-powered heat makes an appealing read for those who happen to be housebound.

Add all composting champions wanting to know more about useable energy which can be captured via the basic composting process.

Gaelan Brown has previously been a guest writer on Green Building Elements about compost-powered heat. He wrote me, asking readers to “Imagine being able to heat water, buildings, and greenhouses using energy captured from compost without buying or burning any fuel while creating a byproduct that is worth more per ton than coal.”

He also is author of The Compost-Powered Water Heater.

Of the book, he says it gives a “broad and deep introduction to compost heat recovery at all scales.”

Readers will not only learn about composting basics and energy recovery, they can discover modern engineered approaches for  extracting heat from compost systems using animal manure and food scraps as the main input.

You could think of compost power as hot shit, but there need be no obnoxious odors or manure involved. In fact, compost-heat-recovery systems often have the added benefit or reducing or eliminating odors that might otherwise be part of the compost production process.

In short, rot makes hot.  And at present there are people all over the world who seem to have collectively scratched their heads at the same time and said, “Let’s use that compost heat. Why not?”

In recent years the resurgence of organic farming in Western economies has driven investments in expanded production of high-value compost. Cost increases for conventional fertilizers and shortages of supplies like potash have driven up the demand and prices for organic compost. Certified-organic products cannot use the chemically derived fertilizers of conventional agriculture that have been common during the past half-century.

His hands-on techniques have a lot of appeal, especially when considering how much waste goes unused.

Mr. Brown reports there are plenty of working examples of homes, greenhouses, and farms that have used compost-heat recovery systems alongside existing heating/hot-water systems, reducing or eliminating the need for fuel combustion. “These systems range from simple low-tech designs made mostly of wood chips and sawdust, to large-scale engineered systems at farms and compost-production facilities,” he says.

Concerning his background, Brown has been involved with compost-powered heating systems in dozens of states across the United States as well as Quebec, Ontario, Siberia, Norway, Chile, Argentina, and many other locales. 

He cites an engineered approach to compost-heat recovery that has been developed by Agrilab Technologies and Joe Oullette of Acrolab Ltd. Called the Isobar system, it draws hot steamy air through the compost into the floor and runs that air and vapor through a specialized heat exchanger.

Brown says the Isobar system in general pays for itself in less than five years and is ideal for commercial compost producers and farms with more than 100 cows or the equivalent amount of manure or other compost feed stocks such as food scraps and forest residues.

There are several Isobar systems in successful operation in VT, NH and NY that are each capturing an average of 1000 BTUs/hr per ton of compost continuously during an 8-week batch cycle. This amounts to more than 1.4 million BTUs of thermal energy captured per ton of compostable materials processed, which is worth about $45 in terms of hot water fuel savings. Forty-five dollars in energy value per ton of compost produced is a very large value. A ton of high quality coal currently costs $40 by comparison.

For those wanting to know more, Brown added:

Jasper Hill Farm in Greensboro, Vermont heats a large winter greenhouse and large volumes of wash water with their Isobar system. The University of New Hampshire’s organic dairy farm and Sunset View Farms in New York, use their Isobar systems primarily for making combustion-free hot water. More information about the Isobar system including “How it works” videos can be found at these websites: CompostPower and AgrilabTech.

Photos via Gaelan Brown and Agrilab Tech.