Top 5 Energy Savers on Dairy Operations
“Whether a producer is doing regular maintenance, seeking opportunities to make an older facility more efficient or contemplating a new building, changes can result in significant and immediate cost and energy savings," said Craig Metz, CEO of EnSave, a leading farm energy efficiency firm and a member of the Innovation Center for U.S. Dairy’s Sustainability Council. “Many improvements come with a one to five-year payback on installation cost.”
The top five most common energy audit recommendations, identified by EnSave and provided in the Best Management Practices, are based on technologies that provide energy savings with a short payback period, including:
1. Lighting — Compact fluorescent lights are more efficient than incandescent light bulbs, which convert only 10 percent of energy used for light. Similarly, T-5 and T-8 fluorescent fixtures with electronic ballasts use about 20 percent less energy than the older T-12s, and also generate less noise, more light per watt, and provide other benefits. For exterior lighting, pulse-start metal halide lighting is long lasting and energy efficient. It also produces more lumens per watt and better light quality than high pressure sodium, probe start metal halide, and mercury vapor lights. Light-emitting diodes (LEDs) are another option for outdoor lighting.
2. Plate coolers — Milk cooling costs account for some of the greatest energy expenses on a dairy farm. In operations without precooling, milk typically comes from the cow at about 98° F, flows into a receiver and is pumped into the bulk tank, where compressors cool it to a temperature of about 38° F. In an operation with a plate cooler, well water passes through the plate cooler in one direction and absorbs heat from the warm milk pumped through the plate cooler in the opposite direction before going into the bulk tank. This process of pre-cooling milk reduces compressor run time and requires less energy to cool the milk.
3. Variable speed drives — A variable speed drive (VSD) is a digital controller that regulates the speed of a pump motor and can result in substantial energy savings. When a VSD-controlled milk pump is coupled with a milk plate cooler, producers have witnessed an average energy savings of 30 percent on the run time of the bulk tank compressor.
4. High efficiency compressors — Scroll compressors are the most efficient type of compressor for small and medium farms, and discus compressors are the most efficient option for large farms. Both types of compressors allow for capacity modulation so that the refrigeration system can match capacity to the desired load. High efficiency compressors often require less maintenance are longer lasting than older, inefficient models, and also can help cool milk more consistently.
5. Compressor heat recovery — When cooling milk in a bulk tank or with a chiller, compressors are used to remove the heat from the milk. The heat removed usually is released back into the air by condenser fans. By installing a compressor heat recovery unit, this otherwise wasted heat can be reused to heat water. Since the incoming water is preheated, the water heater has less work to do and likely will last longer. A dairy farm using 225 gallons of heated water every day, for example, can save as much as $1,300 annually on electricity costs.
Energy savings create real value
With support from NRCS, the Innovation Center is focused on accelerating energy conservation and building awareness for on-farm energy audits by collecting and sharing success stories from dairy farms across the United States. Ryan Anglin, a producer from Bentonville, Ark., completed an energy audit in 2011 on his family’s 300-cow dairy.
Although the Anglins had previously installed an energy-efficient vacuum pump VSD, the audit identified an additional $3,800 in potential annual energy cost savings. Recommendations included changes to the milk cooling system and continued replacements of lighting fixtures.
Anglin said the audit process was painless and the results invaluable.
“Our EnSave energy auditor was very knowledgeable. The entire audit took no more than an hour and a half, and the report is very detailed,” said Anglin. “In our farm plan, we look at cause and effect or cost and income – that is the bottom line. An energy audit is an excellent decision-making tool for
While all dairy farms differ, one thing is universally true — saving energy directly translates into cost savings and improved efficiencies.