Ammonia Refrigeration Expansion

Grande Cheese FactoryAWARDS AGC Build Wisconsin Award 2008

CLIENT Grande Cheese, Fond du Lac, Wisconsin

GOALS  To triple production by increasing manufacturing and refrigerated cooler space, while saving energy, reducing maintenance costs and increasing safety.

OVERVIEW The Rohde team redesigned an ammonia refrigeration system expansion with integrated controls, using the existing infrastructure.


  • Rohde designed, engineered and implemented the system in 7-1/2 months.
  • Rohde’s redesign eliminated the high pressure receiver and redesigned the expansion devices to significantly reduce the ammonia charge required in the system.
  • Base bid on the system was 14,000 lbs.  Rohde’s design reduced it to 7,000 lbs.
  • Budget constraints were met using innovative time management and project design methods.


  • Variable frequency drives on all components including two new 150 hp compressors.
  • Low discharge pressure design, allowing system to run at much lower pressure in cooler months.
  • Elimination of the high pressure receiver and requirement for high discharge pressure to push the liquid to the various components.
  • Redesign of all expansion devices to eliminate need to move high pressure liquid into evaporator coils.
  • The redesign eliminated the surge drums, eliminating need to change relief valves every five years.
  • The coil circuiting design carries oil back to the recirculation vessel where it is drained at a single point in the ammonia room rather than several points on the roof.  

Ammonia refrigeration tankCLIENT SATISFACTION

  • The system redesign saves over 38% in electrical costs and significantly reduces maintenance.
  • The reduced charge holds levels below EPA and OSHA thresholds, eliminating the need for a full  Process Safety Management program (PSM) and $30,000 in consulting fees.


Rohde’s constant focus on innovation in engineering allows it to help industry partners reduce energy costs while implementing efficiencies.