Cool That Energy Bill

Cool that
energy bill

High-volume, low-speed fans can help save you money.

by Todd Fitchette

High-volume, low-speed fans are being compared to the smaller high-speed fans in a freestall barn application in Tulare, Calif. The larger fans move more air and use about the same energy as a high-speed fan.

Happy cows are cool cows. And cool cows are higher-producing cows.
    There are now more ways than ever to keep your cows cool during the summer, and face it, the battle isn’t just in keeping cows cool, but how comfortable these cooling systems are to your checkbook.
    A new way to move air in dairy parlors and freestalls is being touted by one utility company as a way to move more air and pay less to do it.
    What appears to be nothing more than extremely large ceiling fans hang in two dairies in Tulare, Calif. At first sight the 20-foot fans with their thin blades don’t look like much. But, flip the switch and high volumes of air is suddenly circulating.
    Tom Shultz, the University of California Cooperative Extension dairy advisor in Tulare County, has been studying the effects of the fans since they were installed in August. While he doesn’t have enough data on the high-volume, low-speed fans to conclude anything scientifically significant, dairy producers at the two dairies where Southern California Edison (SCE) has installed the fans as part of a study, say the fans seem to be making a difference.
    Frank Nunes, a partner in Nunes Brothers Dairy in Tulare, said he can definitely feel a difference from the three fans placed in the milk barn.
    Prior to the installation, the only air movement in the dairy parlor came from a 36-inch high-speed fan over the lane where milkers stand, and what naturally flowed through from prevailing winds.
    According to Paul Williams, an engineer with SCE, the hope is to provide a cost-savings to dairy producers because fewer of the large high-volume fans will be needed to effectively cool dairy cows.
    “We’re hoping that if these fans work as well as the others… we can help dairymen save money,” Williams said.
    Compared to the 36-inch fans commonly found in dairy barns, the high-volume fans draw basically the same power to run – about one-half horsepower or about 400 watts.
    Unlike their smaller counterparts, the large fans move a greater volume of air. And while their cost-per-unit is higher than the smaller fans, the sales pitch is fewer of the larger fans will be needed. Whereas the main cooling effect of the smaller fans can only be felt a short distance away and perpendicular to the fan, the high-volume fans have a much greater coverage area and aren’t as dependent on whether the cows are standing or lying directly beneath the fan. In short, you don’t have to stand directly under the fan to feel its effect.
    Because of this, it takes fewer of the large fans to move air throughout the entire dairy barn – or the freestall area, wherever you decide to put them. Fewer fans mean fewer kilowatt hours and that translates directly into a cost savings on the utility bill.
    “These fans will move four times the air at the same cost,” Williams said.
    Shultz is studying the effects of the fans in a dairy barn application at Nunes Brothers Dairy, and in a freestall application at McMoo Dairy. In the freestall application, Shultz is comparing cow comfort in two identically-constructed freestalls. One has eight of the high-volume fans spanning the length of the freestall barn, while the other freestall has 52 36-inch high-speed fans. Both barns have an open center and a 4:12 pitch roof.
    According to Brodie McClain, a partner in McMoo Farms in Tulare, the comfort level in the barn with the high-volume fans appears higher.
    “It feels more comfortable in here,” he said. “Overall we’re pretty happy.”
    Unlike the milking parlor application, McMoo Farms has 24-foot fans installed in the roof. These fans require a three-quarter horsepower motor.
    Along with lowering the temperature in the barns, Shultz said he’s seen a reduction in the relative humidity levels in both the dairy barn and the freestall barn applications.
    According to McClain, the added benefit in the freestalls is the lack of other hardware needed to keep cows cool. In the freestall with the large fans, he also uses a soaker to wet the cows for added cooling. In the other freestall where the three-foot, high-speed fans are located, he maintains a high-pressure mist on the fans plus a soaker line.

High-speed fans like this over the milk stalls still contribute to air flow, but are being billed as less-efficient because they use the same energy as newer high-volume fans being sold by some companies.

Michael Ribeiro, a partner in Ribeiro Dairy Farms of Tulare, was one of the dairy producers at a high-volume fan demonstration co-hosted by Southern California Edison. Here Ribeiro speaks with Paul Williams, an engineer with SCE, who demonstrates the effectiveness of the fans with a hand-held bubble machine.

    Another system being touted operates on the idea that higher velocities is what’s needed for a greater cooling effect.
    Open Space Cooling builds fans called EnvironCool™ wind machines. These large, oscillating wind machines look more like the fans used in vineyards and orchard applications to protect against frost.
    Each unit can move upwards of 50,000 cubic feet of air per minute, according to sales literature, and studies of the machines by Dennis Armstrong, a dairy extension specialist and research scientist in Arizona, indicate the fans do aid in cow comfort. And, unlike the ceiling fan types, which blow air down, the OSC fans move air horizontally, which Bill Lanting, a sales representative for OSC, says also aids in moving the gasses out of the freestalls that can speed up deterioration of the metal materials used to construct the barns.
    While the Tulare, Calif. dairy parlor application study is complete – this one looks only at the ceiling fan models, Shultz says the data hasn’t been fully analyzed. Still, he can conclude that it’s definitely better to have fans than none at all. He also said energy use still needs to be compared.
    “The best I can say is it appeared to help,” he said.
    In the freestall study, Shultz wants a full summer before making any assumptions or conclusions. Although the fans appeared to move more air, the freestall also has a 4:12 pitch roof with an open top. The fans installed are blowing down, which Shultz says begs the question: “Is this counterproductive to the design of the barn?”
    Shultz advises dairy producers to compare energy, maintenance and installation costs of the various fan designs on the market before having them installed.