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Save ENERGY, Save MONEY
Conservation Practices that Save: Energy Conservation in Confined Animal
Operations
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In swine operations, electric motors may be used to
pump water for drinking and for the manure flushing system, move feed from
the feed bulk tank to the feeder line, and run the powerful exhaust fans.
Worn or inefficient motors, belts, or fans can add significantly to the
cost of operation. |
Simple changes in confined animal operations can help
farmers and ranchers achieve significant cost and energy savings.
Confined animal operations require a great deal of energy for lighting; heating
of barns and brooders; fans for ventilation and cooling of facilities; pumps for
moving water, waste, or milk; electric motors to run feeders; and electricity
for cooling milk and eggs. Because confined animal operations must be
intensively managed, it is relatively easy to make energy-saving changes to the
operation.
All of agriculture, and particularly confined animal production, makes wide use
of electric motors. With simple, regular maintenance, producers can save
significant amounts of energy and money. Often, if a motor is working, it gets
very little thought or attention from the farmer. Just because it is working,
however, does not mean that it is working as efficiently as possible. Certain
trouble spots often cause a motor to waste energy, including rusty or corroded
moving parts on motor-driven equipment, dry or worn bearings, or belt drives
that are too loose, too tight, or not aligned. Worn pulleys and belts need to be
checked and replaced often. Even if a fan belt is tight, it may still need
replacing. The belt or the pulley itself might be worn, reducing the speed of
the fan and the efficiency with which it runs. A worn belt can easily reduce
output by 20 percent or more. Considering the current cost of energy, producers
might want to think about replacing aging motors. A bank of seven,
well-maintained 48” fans in a broiler house will cost an average of $13.20 per
day to operate at eight cents per kilowatt hour. These same fans, if poorly
maintained, may cost 20 percent more, or $15.84 per day to operate. Over a year,
this difference for fan maintenance can amount to nearly one thousand dollars
per broiler house.
High-efficiency motors can reduce energy consumption by 3 to 8 percent and might
be substituted for other motors. Because of their high cost, high-efficiency
motors might only make sense for high horsepower motors operating at least 2,500
hours per year .
The swine and poultry industries rely very heavily on fans and ventilation
systems to remove gases from the tightly built production buildings, and
maintain proper temperatures for the animals. To help mitigate energy use, the
broiler industry has largely adopted a system called “tunnel ventilation” where
large banks of fans at one end of the house draw large amounts of air at
relatively high speed over the birds. This air provides air conditioning by a
“wind-chill” effect. This usually is coupled with an evaporative cooling system
which further reduces broiler house temperatures . Dirty fans and shutters can
reduce air-moving capacity of the fan by well over 30 percent , reducing the
cooling effect and using more energy. Regular cleaning will maintain the
efficiency of the fan, and guarantee that energy dollars are being used
efficiently.
A number of commercial air-to-air heat exchanger systems are available for
confined animal operations that transfer warmth from exhaust air to incoming
air, resulting in large savings in heating costs. These systems are particularly
applicable to swine nursery operations, and work has shown that these systems
could save up to 40 percent of the energy needed for broiler brooding. Research
has been done in swine and poultry operations, using “earth tubes” to utilize
geothermal resources to heat and cool incoming air.
Dairy operations may benefit from adjustable speed drives in vacuum milking
systems as a means of saving energy. Vacuum pumps run the milking machines that
attach to the cow’s udder, then pump the milk from the milking parlor to the
holding tank. Vacuum pumps often are oversized and run at constant high speed to
meet the maximum need of the operation. If less than maximum is needed, the
excess is wasted. With an adjustable, computer-driven speed drive on the vacuum
pump motor, the capacity of the pump is matched to the actual need for vacuum.
The pump will run more efficiently, reducing energy needs and cost.
Dairy operations need to cool milk rapidly from 102 degrees Fahrenheit (the
temperature at which it leaves the cow) to around 34o F in the holding tank .
Using heat exchangers to transfer this heat to cold water removes the heat from
the milk and raises the temperature of the water, allowing the warmed water to
be used for other things. The warmed water can be used for wash down of cattle
and milking parlors, or it can be heated further to a point where it can be used
for high temperature cleaning of milking equipment. On a 500-cow dairy, transfer
of heat from milk to water saves the equivalent of 215,000 BTUs of energy that
normally would be provided by purchased electricity. The economic advantages of
installing heat exchangers in a milking operation can exceed $3,600 (at eight
cents per kilowatt) in energy savings annually.
All confined animal operations rely heavily on electric lighting, often to
increase the production of milk, eggs, and other commodities. Dairy cows given
16 hours of light continuously each day will increase milk production from 5 to
16 percent, increase feed intake by about 6 percent, and maintain reproductive
performance, compared to cows receiving 13.5 hours or less of light . Lights
also physiologically stimulate egg production in chickens and turkeys.
Changing electric lighting from incandescent lights to fluorescent or to high
pressure sodium lamps can provide all the lighting that farm animals need, at a
reduced cost of operation and with a large increase in energy conservation.
Switching from incandescent to U-tube fluorescent lights can save energy needed
for lighting by 75 percent. In a 40,000-bird-broiler operation, for example,
this equates to a savings of nearly 18,000 kilowatt-hours per year . At a
typical electric rate of eight cents per kilowatt, this becomes a savings of
over $1,400 per year per broiler house.
Operators of confined livestock operations can be good stewards of the
environment while saving on production costs by adopting these and other
available methods of energy conservation.
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Conservation
Practices that Save: Energy Conservation in Confined Animal Operations
NRCS supports conservation practices that save producers money and improve the
environmental health of the Nation. For more information on energy-saving
conservation practices, visit the NRCS “Save ENERGY, Save MONEY” Web site at
www.nrcs.usda.gov.
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