Bill Harvill has six broiler houses and his son in-law, Joe Guinn, has eight broiler houses nearby in Southwestern Missouri. Both growers raise around seven flocks of four pound broilers each year, so they burn a lot of propane starting chicks and keeping the houses warm in the winter time. As propane prices climbed, they looked for another way to heat their houses.
Harvill looked into a number of alternative fuels, but settled on using a corn furnace. Corn is readily available, can be grown on Harvill’s farm, is easy to auger, burns cleanly and produces a lot of British Thermal Units (BTUs) of heat. There is very little ash left after burning corn. One bushel of corn produces 450,000 BTUs of heat and one gallon of propane has 90,000 BTUs, so a bushel of corn has the heating value of five gallons of propane.
Burning one bushel of corn produces five times the BTUS of one gallon of propane.
Steve Schoen, owner of Schoen Equipment, Freistatt, Mo., teamed with Harvill to test a corn furnace on Harvill’s farm. The prototype furnaces which they used had a heating capacity of 450,000 BTUs. Three houses on Harvill’s farm were heated using corn furnaces. The furnaces are located in sheds attached to the outside the poultry house. By products of burning hydrocarbon fuels like propane or wood are water vapor and carbon dioxide. Combustion with the corn furnace occurs outside the poultry house, and the carbon dioxide and water vapor are exhausted outside. Research conducted by Auburn University has shown the advantages for air quality inside the broiler house if combustion occurs outside the house (see Auburn newsletter). Burning propane or natural gas inside the house raises the humidity of the air, and this can lead to increased ammonia production in the litter and increases the need for ventilation.
Harvill and Schoen have designed a new corn furnace for heating poultry houses, the 600 Rocket Biomass Renewable Corn Furnace which has a BTU rating of 600,000. This furnace is thermostatically controlled and can work with a poultry house controller. Poultry house air is drawn in to the furnace to be heated and returned to the broiler house by an 11,000 cubic feet per minute fan. Grain can be fed to the furnace by an auger system from a bin. The furnace has two 16 inch rotating fire boxes and it can burn corn that has not been cleaned. Hot air pushed into the house from the furnace is distributed in the house by ductwork.
The 2006 residential retail average price for propane in the USA as reported by the Department of Energy was $1.88 per gallon. The five year average propane price, for the period 2002 to 2006, was $1.47 per gallon. Corn prices in the USA have averaged around $3.20 per bushel so far in 2007, according to USDA data. On a BTU basis, this corn price is equivalent to a propane price of $0.64 per gallon versus an actual average price for last year of $1.88 per gallon. Depending on the location of the farm, a typical broiler house can burn 5,000 gallons of fuel, or more per year. If these 5,000 gallons of $1.88 per gallon propane were replaced by $3.20 corn, this would have yielded an energy cost savings of $6,200.00 in a year. Even $4.00 per bushel corn would give a price per BTU equivalent to $0.80 per gallon propane.