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12 energy-efficient options to save money in the milking parlor

Christopher Abbott-Koch for Progressive Dairyman Published on 04 November 2016

If you have decided to install a new barn or parlor on your dairy farm, you already know the process involves many choices. You are looking to optimize your space to maximize your production and keep your cows comfortable, but don’t forget to consider options that will save you money over the life of your equipment.

With energy being one of the most expensive operating costs for your dairy, you will want to consider energy efficiency when constructing a new building. Don’t end up spending more for energy than necessary by putting yesterday’s technology into your new dairy building.

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Since you have to purchase new equipment anyway, consider getting the most energy-efficient options possible. It may cost you a little more up-front, but the investment pays for itself many times over with lower overall energy costs. Here are some tips to keep in mind to optimize the efficiency of your new milking parlor or barn:

1. Lighting
Consider installing light-emitting diode (LED) fixtures. They provide many benefits over the traditionally high-wattage fixtures used in milking parlors and barns. LEDs typically consume 50 to 75 percent less energy than standard lighting fixtures such as incandescent, mercury vapor, metal halide, high-pressure sodium and halogen.

They also have a longer fixture life, lower maintenance costs and no mercury in the fixture.

2. Ventilation
It is often more cost-effective to buy a more expensive, more efficient fan because lower operating costs over the fan’s lifetime will make up for the higher initial cost.

Circulation fans are the most common type of fan on dairies and are typically rated based on the pounds of force per kilowatt of power rating; the higher the pounds of force per kilowatt of power rating, the higher the efficiency. Exhaust fans are typically rated based on the cubic feet of air moved per minute per watt of power rating and air flow ratio.

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When purchasing fans, look for fans that are in the top 5 percent of energy-efficient fans tested by the Bioenvironmental and Structural Systems Laboratory at the University of Illinois. Adding a variable speed fan controller is also an option for ventilation energy efficiency.

3. Vacuum pump VFDs
A variable frequency drive (VFD) gauges the amount of vacuum suction needed in the parlor and adjusts the speed of the pump motor to deliver only the amount of suction needed. The energy savings comes from the reduced demand of the vacuum pump.

A VFD can reduce vacuum pump electric use by 50 to 60 percent, assuming a power requirement of 0.25 horsepower per milking unit during milking.

4. Plate coolers and milk pump VFDs
Plate coolers consist of a set of stainless steel plates installed in the milk line between the receiver jar and bulk tank. Water or glycol passes through the plate cooler in one direction and absorbs heat from milk passing in the opposite direction, reducing the temperature of the milk before it enters the bulk tank or passes through a chiller. This process can substantially reduce milk cooling loads.

When coupled with a milk pump VFD, even more savings can be realized. A milk pump VFD regulates the milk flow over the plates, thereby allowing time for maximum cooling to take place.

The ideal milk transfer would pump the milk at the slowest and most constant rate possible through the plate cooler. Tests have shown energy savings for the milk cooling system of up to 30 percent when the milk pump is controlled by a VFD coupled with a plate cooler.

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5. High-efficiency scroll and discus compressor
Whether you plan on installing bulk tank compressors or a chiller system, there are high-efficiency compressor options available that use about 30 percent less electricity than conventional compressors.

If you are installing bulk tank compressors, then digitally controlled scroll compressors with capacity modulation are the most efficient option. Scroll compressors save energy by constantly compressing the refrigerant gas in a smooth motion, while reciprocating compressors use a piston to compress the gas over a much smaller volume repeatedly.

Scroll compressors also have fewer moving parts, making them quieter and more reliable than reciprocating compressors.

If installing a chiller system, then high-efficiency discus compressors are another option and have a similar performance rating to scroll compressors. Discus compressors can often be more efficient than scroll compressors for capacities above 10 horsepower and are available with digital controls and capacity modulation.

Work with your refrigeration technician to choose the most efficient compressor available that best meets the needs of the farm.

6. Premium efficiency motors
NEMA Premium electric motors have higher efficiencies, lower electrical power consumption and costs, and higher system reliability than standard motors. When installing a new motor, consider using a NEMA Premium motor. While NEMA Premium motors may cost more initially, the payback is significant over their operating life in most applications, especially in areas where electricity prices are high.

Premium efficiency motors are also usually made to higher manufacturing standards and stricter quality controls than regular efficiency motors. This can often mean the motor will last longer, with fewer maintenance costs and less downtime.

7. Ozone laundry
If you need a commercial-sized washing machine in your parlor, consider installing an ozone laundry system. An ozone laundry system uses ozone gas instead of heat and detergent to clean and disinfect laundry, reducing hot water usage associated with laundry by 80 to 100 percent and reducing overall water consumption by about 25 percent.

An ozone laundry system also reduces the use of chemicals used for cleaning and actually kills viruses and bacteria better than bleach. Other non-energy benefits include savings in labor and drying time.

8. Compressor heat recovery
Compressor heat recovery units are insulated storage tanks that use waste heat from the bulk tank and chiller compressors to pre-heat water to approximately 110ºF before it enters a conventional water heater. This process cuts water heating costs by up to 50 percent and can extend the life of your refrigeration system.

9. Water heaters
Heaters should be chosen by how much hot water is needed over a specific period of time. On dairy farms, this is usually how many gallons per cycle are required for the milking system and bulk tank. Use the highest Energy Factor rating for fuel type used on the operation.

If gas is used, select a heater with an Energy Factor rating of 0.8 or greater. If electric is used, look for an Energy Factor rating of 0.91 or greater.

10. Parlor pit radiant heaters
Rather than heating the air, radiant tube heaters use radiant energy to efficiently heat the objects in a particular space. If the milking parlor is heated during the winter months, a radiant tube heater positioned above the parlor pit is a great option for worker comfort.

11. Conductive cow cooling
Conductive cooling is a newer technology using heat exchanger pads buried within each stall to circulate cooled water or glycol. Contact between the heat exchanger and cow bedding creates heat transfer through conduction, effectively drawing the heat from the cow through the bedding and into the cooling fluid.

Closed-loop conductive cow cooling systems can reduce electricity consumption by lowering the demand on ventilation fans by reducing run times during peak load periods as well as potentially significantly reducing water consumption used for cow cooling through recirculation.

This technology is still in the development phase, but initial research presents very promising energy and water savings. The water savings may make this technology especially pertinent if your dairy is located in a drought-prone area.

12. Electronic expansion valves
Electronic expansion valves allow compressor set points to change with the ambient temperature, increasing the cooling capacity of the compressor when the ambient temperature drops.

Electronic expansion valves are readily used in commercial applications such as supermarkets to save energy on cooling costs, and the technology is transferable to dairies.  end mark

Christopher Abbott-Koch

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