Milk Power: How To Reduce Energy Usage on Dairy Farms
Christopher Columbus brought the first dairy cows over on his second voyage to the new world. Since that time, dairy farms have gradually changed. They’ve evolved from a cow or two per family to small, localized dairy farms to large endeavors.
Dairy farms are transforming once more. This time, farmers are looking for ways to reduce and/or recycle the power used in pumping milk. This will help them to reduce energy costs and address environmental concerns.
There are two opportunities to reduce energy usage in the milk pumping process:
- Variable Speed Drive (VSD)
Milking takes place two or three times a day on the average dairy farm. The farmer uses a milking vacuum pump, which is sized to deliver the maximum power needed for milking and washing. The problem is, this maximum amount is only needed about 1% of the time. The pumps, nevertheless, continue to run at a constant high speed, wasting energy.
Attaching a VSD to the milk vacuum pump turns it into a more efficient machine by controlling the speed and determining exactly how much vacuum the system actually needs. The end result is a pump that operates at a lower speed unless required, and uses significantly less electricity to perform the task.
The VSD also allows milk to flow steadily and more quietly into the bulk tank. In addition there are no energy surges, which allow the plate coolers that chill the milk to operate more proficiently. The amount of electricity saved by using a VSD could be as high as 40%, not an insignificant amount.
- Milk Cooling Systems
Fresh, raw milk must be chilled within one hour of milking from 95-99°F to 38°F so no bacteria builds up, and so that it can be stored safely until it is picked up by the milk hauler. It takes a huge amount of energy – 30% of the farm’s total energy costs – to cool milk this rapidly. Paradoxically, the milk cooling process and the compressors used on farms produce a huge quantity of heat, which is typically vented into the air and wasted, when it could be harnessed for all sorts of other farm uses.
One of the questions dairy farmers are now asking is – how can heat be re-directed and used in better ways on dairy farms?
Re-purposing Milk Cooling Substances to Save Energy
One of the ways the milk is cooled is through a series of stainless steel plates. Cool well water flows down one side chilling the warm milk that flows down the other. This discarded water is clean enough to be used in one of two ways:
- To water the cows. Since dairy cattle drink a gallon and a half of water for every gallon of milk they produce, especially in warm weather, this is great way to re-use the water.
- he excess water can also be used to wash down the equipment or floor of the milking parlor. The heat that is emitted from milk cooling processes and compressors can be reclaimed and used to heat the water for washing down milking equipment. Since it takes four ½ gallons of hot water to clean each milking point, this would result in substantial savings on heating bills.
Reducing Energy Consumption on Farms
Dairy farmers need energy for a variety of applications on their farms – for the pumping mentioned above, to cool and store milk, to heat water for cleaning, and for lighting and ventilation, just to name a few – so it’s essential that they save on energy costs wherever possible.
Of course there are many more opportunities for dairy farms to reduce energy and become more energy efficient, but attaching a variable speed drive to milk pumps and re-using the energy expended from milk cooling systems is a good place to start because it requires little up-front cost for much in return.