Intermediate Ammonia Refrigeration Systems

Upcoming dates (3)

Dec. 4-6, 2024

Madison, WI

Course Overview

During this course, you will expand your understanding of the equipment used in ammonia refrigeration systems and learn application-specific tips.

Who Should Attend?

  • Refrigeration system operators 
  • Plant, facilities, application, and design engineers 
  • Ammonia refrigeration contractors 
  • PSM Coordinators wanting to learn more about the technology 
  • Sales and engineering staff with refrigeration equipment manufacturers

Additional Information

Note: Participants are expected to have completed the Introduction to Ammonia Refrigeration Systems course or have significant work experience with refrigeration systems.

This course is part of the Process Safety Management Professional Certificate. Increase your knowledge and effectiveness at managing PSM/RMP programs for your ammonia refrigerated facility, while earning a recognized credential. Course can be taken individually as well.

Attendees participating in this course will be able to earn a digital badge as evidence of the knowledge they obtained during the course. Digital badges are micro-credentials that can be earned by successfully passing a final quiz administered online after completing the course. Click here for information on digital badges.

Course Outline

Day 1

Workshop Introduction 
Refrigeration Systems Review 

  • Introduction to types of systems: direct expansion, flooded, liquid overfeed
  • System components and arrangements
  • Refrigerant selection criteria

Properties of Ammonia Refrigerants 

  • Fundamental properties: pressure, volume, temperature
  • Derived properties: enthalpy, internal energy, transport
  • Phase change
  • Diagrams: pressure vs. enthalpy, pressure vs. temperature
  • Refrigerant comparison: Fluorochemicals, ammonia, water, CO2
  • Flash gas
  • Subcooling and superheat
  • Influence of water in ammonia refrigerant properties

Psychrometric Properties and Processes

  • Definitions: dry bulb, wet bulb temperatures, humidity ratio, psychrometric chart
  • Psychrometric processes: latent and sensible energy changes
  • Effects of refrigerant evaporating temperature on space humidity levels

Property Workshop

Psychrometric Properties and Processes (continued)

Refrigeration Load Calculations

  • Temperature requirements
  • Loads: envelope, product, other internal heat gains
  • Evaporator fan heat gains
  • Make-up air loads
  • Door loads - theory vs. real-world


Day 2

Refrigeration Cycles and Cycle Performance

  • Conservation principles
  • Performance measures
  • Capacity and required refrigerant mass flow rates
  • Overview of multi-stage systems

Compressors and Compressor Performance

  • Interpreting compressor maps
  • Correcting for actual compressor application/operation
  • Compression ratio limits
  • Part-load and off-design operation
  • Oil cooler heat rejection methods (screw compressors)
  • Economized ratings - when to/not to use (screw compressors)

Compressor Workshop

Vessels and Refrigerant Pumps

  • Types: high-pressure receiver, low-pressure accumulator, flash intercooler
  • Configurations: horizontal or vertical
  • Ratings
  • Proper practices for system integration
  • Knock-out velocity and down-comer sizing
  • Pump types and performance curves
  • Net positive suction head available vs. required
  • Refrigerant pump cavitation (causes and cures)


Day 3


  • Types
  • Performance characteristics and ratings
  • Selection and operation
  • Configuration: top feed or bottom feed
  • Defrosting techniques
  • Effects of pressure regulators
  • Determining optimum refrigerant feed rates (overfeed systems)

Condensers and Heat Recovery

  • System Types
  • Performance characteristics
  • Selection
  • Heat recovery potential


  • Condensers: liquid refrigerant hold-up, proper practices for parallel condenser operation
  • Evaporator defrost best-practices
  • Open question and answer


Todd Jekel

Todd Jekel, PhD, PE is the assistant director of the Industrial Refrigeration Consortium at the University of Wisconsin–Madison. Jekel has been actively conducting research on refrigeration systems including vessel design practices, oil separators, and analysis of dehumidification alternatives for cold storage warehouses. He holds degrees from Calvin College and the University of Wisconsin–Madison.

Marc Claas

Marc Claas is an Associate Researcher with the Industrial Refrigeration Consortium and has been involved in industrial refrigeration since 2009. His interests include refrigeration system maintenance requirements, criteria for safe system operation, troubleshooting systems for safe and efficient operation, regulatory compliance in refrigeration systems, and emerging cooling technologies. His teaching experience includes online operator training programs, and his field experience includes PSM related activities such as PSM audits and PHAs. He also has experience investigating energy efficiency and other operational opportunities. Claas holds a Bachelor’s degree in Mechanical Engineering from UW-Platteville and Master’s of Mechanical Engineering in Thermal Science from UW-Madison. He is an active member of the International Institute of Ammonia Refrigeration.

Douglas Reindl

Douglas Reindl, PhD, PE is a professor at the Department of Mechanical Engineering and a Program Director at the Office of Interdisciplinary Professional Programs at the University of Wisconsin-Madison. He has extensive experience in mechanical systems – including industrial ammonia refrigeration systems. As the founding director of the Industrial Refrigeration Consortium, he works extensively to improve the safety, efficiency, reliability, and productivity of ammonia refrigeration infrastructure. Dr. Reindl received his BS in mechanical engineering technology from the Milwaukee School of Engineering, MS in mechanical engineering from UW–Madison, and PhD in mechanical engineering from UW–Madison. He is a registered professional engineer in the State of Wisconsin.

Upcoming dates (3)

Program Director

Douglas Reindl

Contact Us

Create a custom learning experience

We can deliver this course as an on-site learning experience tailored to your organization’s specific training needs.