Heat recovery with the Mueller Fre-Heater®

On a dairy farm, a lot of hot water is used every day to clean the milking installation or milk cooling tank. Mueller has various options for saving on energy costs with a Mueller heat recovery system. Savings can even increase to more than 1,000 pounds per year. The Fre-Heater® is a heat recovery system that uses the heat released when cooling milk.

Saving energy through heat recovery

During the cooling of the milk, recover heat released into the environment with a Mueller heat recovery system. Use the recovered heat to heat water free of charge. Water heated via a boiler can be used for cleaning the milking parlor and milk cooling tank. Because the water in the boiler reaches the desired temperature faster, you save considerably on your heating bill. Depending on your milk cooling system and the amount of milk you produce, the Fre-Heater may support all of your hot water needs.

The Fre-Heater is reliable and maintenance-friendly

The Fre-Heater consists of a glass-lined, enameled steel inner vessel fitted with a stainless steel Temp-plate® heat exchanger all around: both layers safeguard your potable water from coolant contamination. Depending on the circumstances, the system supplies water at about 35-45˚C. The absence of moving parts, such as a circulation pump and thermostat, makes the Fre-Heater particularly reliable and maintenance-friendly.


  • Stainless steel outer jacket. Rust resistant exterior requires no maintenance.
  • Mueller Temp-Plate heat transfer surface cools the super-heated refrigerant from the milk cooling condensing units and harvests the system’s wasted heat energy.
  • Industrial-grade, fully insulated, glass-lined storage tank assures minimal heat loss and long-term reliability.
  • Factory-installed anode(s) provides superior galvanic corrosion protection for the water storage tank. Model D-120 has 2 anodes, and Models D-50 and D-80 each have 1 anode.
  • Five-year limited warranty protects your purchase.
  • Complies with CSA regulations for the United States and Canada.

Specifications and Sizing

Model No. Part No. Water Connection (in) No. of Refrig. Circuits Refrig. Connection Size (in) Per Circuit Refrig. Application Capacity* Height (in) Diameter (in) Approx. Shipping Weight (lb)
D-50 8823750 ¾ MPT 1 5/8 ODM .5-4 ton R-22/507 53.875 21.75 225 
D2-50 8823751 ¾ MPT 2 5/8 ODM .5-4 ton R-22/507 53.875 21.75  225 
D-80 8823780 ¾ MPT 2 ¾ ODM 1-5 ton R-22/507 58.625 25.25  320 
D-120 8823821 1½ FPT 2 ¾ ODM 1-7.5 ton R-22/507 61.75 29.5  475 
D2-120 8823820 1½ FPT 2 1 1/8 ODM 3-15 R-22/507 61.75  29.5  475 
DH-120 8823823 1½ FPT 2 1 5/8 ODM 7-35 ton R-22/507 61.75 29.5  475 
DE-120 8823822 1½ FPT 2 1 1/8 ODM 3-15 ton R-22/507  61.75  29.5  475

*Refrigeration tonnage capacities are 30°F evaporator ton loads, not total heat of rejection tons. Pressure drop through a Fre-Heater refrigeration circuit will be approximately 15 psi at the maximum tonnage application. Pressure drop at the mid-range of tonnage application will be approximately 5 to 7 psi. The best overall refrigeration/heat recovery system efficiency is usually obtained at or below the mid-range tonnage application.


See how you can save energy with your milk cooling system.


Our Dairy Farm Partners

We are proud to partner with these leaders in the dairy farming industry. From legacy farms that have thrived through multiple generations to solar cooling in Africa that is providing young children their first taste of cold milk, our equipment is impacting lives around the world.