Ventilation fans are critical in animal barns for delivering fresh air and removing heat, moisture, and dust. But measuring a fan's performance in a barn has been difficult.
"Traditional techniques have been cumbersome, inaccurate by 8 to 10 percent, and slow—taking 30 to 45 minutes," says animal physiologist J. David May, who is with the Agricultural Research Service.
May, agricultural engineer John D. Simmons, and animal scientist Berry D. Lott at the ARS Poultry Research Unit in Mississippi State, Mississippi, overcame these problems. They designed and built FANS, short for fan assessment numeration system.
FANS quickly and accurately measures air output of large, in-place ventilation fans. The system consists of a portable anemometer—an instrument developed to measure windspeed—plus a computer and software to record and analyze measurements.
"FANS helps solve the thorny technical problem of measuring the output of in-place ventilation fans in animal barns," says May. "Such measurements had been theoretically possible but not technically feasible until now. The anemometer can measure volumetric flow rates with 99-percent accuracy in less than 4 minutes."
The anemometer has been used in ARS studies on fan components including shutters, exhaust cones, belt guards, and propellers. Future studies will test fan output on light baffles, fan belt condition, dust, and static pressure.
The scientists assembled and calibrated the anemometer in cooperation with Thomas E. Hannigan, who is at the Aerospace Engineering Department at Mississippi State University. A major fan manufacturer, Hired Hand Manufacturing Co., of Bremen, Alabama, validated FANS at its flow laboratory.
While primarily a research tool, FANS has many useful applications. For example, it saved a major egg company more than $200,000. To protect employees from possible hand injuries, the company installed belt guards on 1,100 fans in 115 poultry houses.
FANS showed that ventilation remained adequate with the guards installed, so the company didn't have to buy additional fans.
FANS can also pinpoint the best location for ventilation fans. It showed that fans placed at the end of a long poultry house are more efficient than those along the side walls at the end.—By Hank Becker, Agricultural Research Service Information Staff.
"FANS Makes Measuring Air Movement a Breeze" was published in the July 1999 issue of Agricultural Research magazine.