Free Heat From Manure Pits

Free Heat From Manure Pits ENERGY Miscellaneous 5-6-14 Every barn built over a manure pit is partially warmed by heat from the composting manure below. Now, a group of Norwegian scientists has managed to tap that heat in pits not only to heat the barn above, but for other farm buildings and the farm home. Hog farmer Njaal Sween of Kylstad, Norway, worked with ag engineers from the Agricultural University in Aas to outfit his 40-sow unit with the first experimental compost heat system. By aerating manure in the pit with a submersible pump to stimulate aerobic digestion, it heats up to as much as 120?. A heat exchange system circulates water through about 900 ft. of 1-in. pipe submerged in the pit and runs it up through radiators in the barn or other buildings. Sween says the system kept his approximately 4,800 sq. ft. barn heated to about 68? throughout the winter even though outside temperatures reached 20? below zero or lower. The system, minus the aeration pump, cost around $2,500. Sween says he saved $1,200 to $1,500 on heating costs and plans to add about 600 more feet of pipe to the system for use this winter. Oddvar Tjernshaugen, engineer at the University of Aas, says the system could also be used in outdoor slurry tanks. Generally, manure should be emptied out twice a year to obtain the most heat from composting manure. He adds that there are advantages of the system besides energy production. "There is a strong reduction inodor by stimulating the bacteria in the manure. Secondly, well-composted manure is easier to handle." For more information, contact: FARM SHOW Followup, Oddvar Tjernshaugen, Agricultural University of Norway, Box 15, N-1432, Aas-NLH Norway.

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