By John Lovett
University of Arkansas System Division of Agriculture
Arkansas Agricultural Experiment Station
FAYETTEVILLE, Ark. — Today’s meat chickens were bred to grow faster with higher feed conversion ratios, but that also makes chicken house climate control even more important.
VENTILATION — Sidewall tunnel fans provide cross ventilation in a chicken house. An 11-month energy audit of chicken house electricity usage showed ventilation fans require the most electricity and prompted further studies on how to curb "peak demand." (U of A System Division of Agriculture photo)
Demand for better climate control, especially ventilation, has increased over the past decade as poultry companies have moved to require fully enclosed chicken houses that support those genetic abilities of the nation’s largest meat protein sector.
Following an 11-month study of a modern broiler chicken house’s electric load pattern, researchers with the University of Arkansas System Division of Agriculture showed the most significant room for energy cost savings for poultry producers lies in avoiding “peak demand” charges associated with ventilation fans.
“We really need to look at the energy efficiency of fans because that’s the biggest energy user,” said Yi Liang, associate professor of biological and agricultural engineering for the Division of Agriculture. “There are also many other components. Lights, for example. However, in the last 10 to 15 years, they have passed from incandescent to fluorescent to LEDs. Now, lights are just a small percentage of electricity usage. Energy efficiency can have a lot of benefits.”
The study, “Measurement of dynamic electric consumption trend in a broiler house in Arkansas,” was published earlier this year by the American Society of Agricultural and Biological Engineers and was co-authored by Thomas Costello, associate professor. Costello retired from the biological and agricultural engineering department in January.
Liang conducts research and outreach through the Division of Agriculture’s Arkansas Agricultural Experiment Station and the Cooperative Extension Service. Her work is also part of the Center of Excellence for Poultry Science.
The chicken house equipment that was monitored included sidewall fans, end-wall fans, circulation fans, compact fluorescent lamps, dimmable LED lamps, feed-bin cross-auger motors, feed-line motors, blowers on radiant-tube heaters, and well-water pump motors for an entire farm. The sump pumps used to deliver water to the cooling cells were not monitored since their electricity consumption is small, Liang said. End-wall fans create high air speed through the house, typically referred to as the “tunnelling effect,” to help cool the chickens.
Due to the difficulty in obtaining real-time measurements, the researchers did not measure fuel usage to heat the production houses.
Costs of peak demand
Their yearlong investigation sought deeper insights into chicken houses’ daily and seasonal energy load, which can be used to assess if incorporating solar arrays on site is feasible to offset peak demand.
Many farm electric accounts, Liang explained, are charged not only for total energy usage but also extra for power used during periods of peak demand. The study used 15 minutes as its peak demand period — the amount of time which utility companies use to compute the most power within a billing cycle.
Liang’s previous published research showed that peak demand charges can account for close to 50 percent of the monthly electricity bill for some farms.
Having investigated chicken house energy consumption for many years, Liang expected ventilation fans to be the biggest user. But even she was a little surprised at just how much. Throughout four growth cycles of heavy broilers, the study showed that ventilation fans accounted for 88 percent of the electricity demand and were the most significant contributor to peak demand on the farm.
Electricity costs over the 11-month production period ranged from $5 per metric ton of chicken for winter flocks to $22 per metric ton for summer flocks respectively.
The results led Liang to a few ideas for further studies.
Controlled power
To offset peak demand, Liang said she would like to work on programming the electric feed motors in a chicken house so they avoid running continuously for 15 minutes when ventilation demand is peaking.
For example, if the ventilation fans are peaking, Liang said she would like to try programming the well water pump to refill at off-peak hours to avoid influencing the peak demand charges.
“Commercial chicken houses have a controller with software guiding the equipment operations as the birds grow” Liang said. “Basically, the controller needs a little bit of an upgrade.”
Liang would also like to test variable speed technology on the chicken house ventilation fans to decrease electricity demand, by slowing them down during months when the required air exchange rates are lower than the design airflow rates. Unfortunately, Liang said, slowing the fans down using variable speed technology means additional capital investment so an in-depth cost benefit analysis is warranted.
This work was supported by the Agriculture and Food Research Initiative - Sustainable Agricultural Systems, project award no. 2019-69012-29905, from the U.S. Department of Agriculture’s National Institute of Food and Agriculture.
To learn more about the Division of Agriculture research, visit the Arkansas Agricultural Experiment Station website. Follow us on X at @ArkAgResearch, subscribe to the Food, Farms and Forests podcast and sign up for our monthly newsletter, the Arkansas Agricultural Research Report. To learn more about the Division of Agriculture, visit uada.edu. Follow us on X at @AgInArk. To learn about extension programs in Arkansas, contact your local Cooperative Extension Service agent or visit uaex.uada.edu.