Variable Frequency Drives: Milk Transfer Pump
alternative practice names:
Milk Transfer Pump Variable Speed Drive (VSD); Milk Pump VFD; Milk Pump VSD; Milk Transfer Pump Motor Controller
A variable frequency drive (VFD) connected to a milk transfer pump motor (milk pump VFD) is a technology that is paired with a plate cooler to further improve the energy efficiency of the milk cooling process.
When milk is pumped from cows, the flow of milk is variable, which creates uneven heat exchange in the plate cooler. A milk pump VFD creates a constant flow of milk through the plate cooler by matching the flow rate of milk with the flow rate of water or glycol flowing through the plate cooler. This is accomplished by using a sensor installed on the receiver tank, which varies the speed of the transfer pump motor.
When used, in what regions in the U.S. is the practice found:
Northwest, West, Upper Midwest, Southwest, Northeast, Southeast
FARM SIZE
When used, typically found on farms of the following sizes:
All Sizes

Practice Benefits
Improved profitability: The main benefit of installing a milk pump VFD is improved profitability by reducing the amount of electricity used to cool milk. By improving the heat exchange of the plate cooler, a milk pump VFD can further reduce demand on the bulk tank refrigeration system, which can increase the useful life of the bulk tank compressors.

Implementation Insights
Site-specific or Farm-specific requirements

Plate cooler: Milk pump VFDs are only appropriate for dairy farms that use a plate cooler for pre-cooling milk before it enters the bulk tank.
Power and pump type: Milk pump VFDs function best with centrifugal milk pumps and 3-phase power, but can be used with single-phase using a phase converter.
Flow rates: Milk pump VFDs are most helpful on farms where water flow rates are not adequate to match the flow of milk through the plate cooler at a one-to-one ratio or greater.
Required Capital Expenditures (CapEx)

Milk pump VFD: The primary expense is the milk pump VFD itself, along with the labor required to install it. The level sensor system required in the receiver tank is part of the milk pump VFD system and will be installed along with the milk pump VFD.
Plate cooler: If a farm does not already have a plate cooler installed, this would be an additional necessary purchase.
Required Operational Expenditures (OpEx)

Maintenance: Ongoing maintenance costs for milk pump VFDs are generally low, and maintenance can be performed in-house without skilled labor. Maintenance of a milk pump VFD primarily involves keeping it dust-free and dry as well as ensuring that the level sensor in the receiver tank remains functional. Maintenance of the plate cooler and components of the milk harvesting system should be performed regularly according to manufacturer recommendations in order to ensure that the benefits of the milk pump VFD are fully realized. The lifespan of a milk pump VFD is typically at least 10 to 20 years.
Implementation Considerations

Cost efficiency: Milk pump VFDs should only be used in conjunction with a plate cooler. In some cases, there are less costly ways to achieve cooling with the plate cooler such as adding plates or upgrading the water supply to the plate cooler.
Selection and installation: It is important to select a high-quality VFD equipped with radiofrequency filters to avoid electrical interference with other equipment on the farm and stray voltage. Milk pump VFDs are generally straightforward to install with assistance from an experienced equipment vendor.
Compatability: Milk pump VFDs function best with centrifugal milk pumps and 3-phase power but can be used with single-phase using a phase converter. If the existing pump and/or motor are incompatible with a VFD, they will need to be replaced.
Financial Considerations and Revenue Streams
FEDERAL COST-SHARE AND CONSERVATION FUNDING
Funding is available for this practice through USDA's Natural Resources Conservation Service (NRCS) Environmental Quality Incentives Program (EQIP) On-Farm Energy Initiative.
Related EQIP Practice Standard: Energy Efficient Agricultural Operation (374).
Notes:
An Agricultural Energy Management Plan (AgEMP), or other qualifying energy audit, needs to be completed before applying for EQIP assistance.
Check with the local NRCS office on payment rates and practice requirements relevant to your location.
The USDA Rural Development Rural Energy for America Program (REAP) also offers competitive grants and loan guarantees for installing energy efficiency projects.
OTHER CONSERVATION FUNDING
Milk transfer pump VFD rebates are sometimes available through the farm’s electric utility company.
Additional Resources

Environmental Impacts
REDUCES FARM GREENHOUSE GAS FOOTPRINT
Improving energy use efficiency reduces a farm's greenhouse gas (GHG) footprint. Since energy production typically involves processes that emit greenhouse gases like carbon dioxide and methane, cutting energy use directly lowers the GHG footprint of the farm.

Alignment with FARM Program
FARM Environmental Stewardship (ES) V2-V3 Alignment
FARM ES captures a farm's energy usage and calculates the associated GHG emissions based on regional energy production and transmission averages. Any practice that reduces farm energy consumption will directly lower the farm's GHG footprint. The reduction in GHG emissions is particularly pronounced in regions where a larger proportion of energy is derived from coal, natural gas, or other fossil fuel sources, as these energy types have higher carbon footprints compared to renewable energy sources.
Contents
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We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights.
A variable frequency drive (VFD) connected to a milk transfer pump motor (milk pump VFD) is a technology that is paired with a plate cooler to further improve the energy efficiency of the milk cooling process.
When milk is pumped from cows, the flow of milk is variable, which creates uneven heat exchange in the plate cooler. A milk pump VFD creates a constant flow of milk through the plate cooler by matching the flow rate of milk with the flow rate of water or glycol flowing through the plate cooler. This is accomplished by using a sensor installed on the receiver tank, which varies the speed of the transfer pump motor.
Practices and technologies
Variable Frequency Drives: Milk Transfer Pump
alternative practice name:
Milk Transfer Pump Variable Speed Drive (VSD); Milk Pump VFD; Milk Pump VSD; Milk Transfer Pump Motor Controller