The Natural Refrigeration Review is a quarterly publication that contains technical articles, regulatory and code updates, industry news and information about IIAR activities and publications. It is distributed by email to all IIAR Members and IIAR Contact lists.
SUMMER 2026 THE NATURAL REFRIGERATION REVIEW
The Natural Refrigeration Review issues are available as PDF downloads for both lIAR members and non-members, or as individual article posts below. Click the button to view the full issue, or scroll through all the individual issue articles below.
2023 Tech Paper: Ammonia Central-stage DX System: Firsthand Experience
The dominant topics for industrial refrigeration facilities have been climate change and rising energy costs in recent years. A new generation of environmental activists worldwide has pushed this agenda forward to the point where politicians have started to alter their countries’ energy policies....
Read More
2022 Tech Paper: CFD-based Design Basis for Avoidance of Hydraulic Shock in Ammonia Pipework Systems
Incidents of ammonia releases due to hydraulic shock in the refrigeration pipework have been reported in the past and could occur in the future. Such shock events carry significant commercial risks and are a concern for the health and safety of humans. Two locations where hydraulic shock occurs f...
Read More
2022 Tech Paper: Proper Installation and Maintenance Practices for Variable Frequency Drives
The use of a variable frequency drive (VFD) to control the speed of an AC induction motor has numerous benefits, including energy savings, improved reliability, reduced equipment wear and tear, and more precise control of motor speed.
Read More
2022 Tech Paper: Managing Your Energy Costs: It Can Be Done!
All too often, energy management projects with good potential will fail for any number of reasons. Most of these failures will be a result of the project not addressing key requirements for success, or not meeting the expectations of all users throughout the organization. This report is intended ...
Read More
2022 Tech Paper: Benefit of Ammonia Heat Pump Implementation in the Industry and for District Heating
Over the last 15 years the market for high-temperature ammonia heat pumps has been growing in Europe and now it is also taking off in North America. That period in Europe has yielded many lessons as higher pressure and temperature present new challenges in refrigerant design. This paper explains ...
Read More
2022 Tech Paper: Absorption Applications for Residential-Light Commercial Space Conditioning and Water Heating
Absorption cycles using the ammonia-water refrigerant pair have a long track record of commercial applications ranging from industrial-size cooling using waste heat as the energy source, to gas-fired residential air-conditioners and small refrigerators for recreational vehicles using propane fuel...
Read More
2022 Tech Paper: Transcritical CO2 Compressors: Technical Challenges in Industrial Refrigeration Application
Carbon dioxide (CO2) has today become the standard refrigerant of choice for many applications, often enabling better coefficient of performance (COP) than the previously adopted technologies based on other refrigerants. This trend is progressively leading to both a lower usage of high global war...
Read More
2022 Tech Paper: Simple Equations for Determining Mass Flow in Refrigeration Systems
The goal of any industrial refrigeration system is to remove heat. Therefore, the total heat load is the design engineer’s first calculation, which is then used to size and select the evaporators. Unfortunately, this heat load is often also applied to the sizing of other components in the system,...
Read More
2022 Tech Paper: Don’t Curse the Purger
The goal of operators, contractors, and design engineers is to operate a closed loop refrigeration system as close to design intent as possible. The owner wants maximum value from the equipment and personnel employed at the facility. The presence of gases that do not liquify within the operating ...
Read More
2022 Tech Paper: Liquid Overfeed Ammonia Refrigerating Plant and Energy Efficiency
The global HFC phase-down and the proposed restrictions on PFAS (per- and polyfluorinated alkyl substances) have accelerated the transition towards natural refrigerants. The requirements of the Paris Agreement, the European CBAM (Carbon Border Adjustment Mechanism) initiative, and ESG (Environmen...
Read More
2022 Tech Paper: Machinery Room Ventilation and Ammonia Release Computational Fluid Dynamics (CFD) Study
The ammonia refrigeration industry has a historically good safety record and hence there have been few instances of ammonia release resulting in ignition events. To continue and improve upon safe practice, computational fluid dynamics (CFD) modeling was undertaken...
Read More
2021 Tech Paper: CFD Analysis of Pipework Fracture due to Hydraulic Shock in an Ammonia Refrigeration System
The condensation induced hydraulic shock (CIHS) phenomena is a primary safety concern in low temperature ammonia systems. When transient pressure amplitudes become exceedingly high, pipe rupture can occur. Of particular interest to the ammonia industry is the development of a computational fluid ...
Read More
2021 Tech Paper: RAGAGEP: Historical Variants and the Importance of IIAR Standards
Recognized and generally accepted good engineering practices (RAGAGEP) are written documents intended for use in the design, installation, operation, and maintenance of process equipment. There has been a movement in the ammonia refrigeration industry towards standardization...
Read More
2021 Tech Paper: Identifying and Quantifying Fugitive Emissions from Industrial Refrigeration Systems
Industrial ammonia refrigeration systems vary widely in their engineering design, size, scope, and technology features. However, they universally experience some level of refrigerant loss throughout their operational life. Refrigerant losses from industrial ammonia refrigeration systems originate...
Read More
2021 Tech Paper: Risk-Based Inspection for the Ammonia Refrigeration Industry
The OSHA Process Safety Management (PSM) program and the EPA Risk Management Plan (RMP) rule rely on mechanical integrity to achieve the desired results. In the case of piping and equipment exposed to anhydrous ammonia, the predominate damage mechanism is external corrosion or corrosion under ins...
Read More
2021 Tech Paper: The Case for HAZOP – Minimizing Effort and Increasing Longevity
Should the hazard and operability (HAZOP) methodology be considered the industry standard for hazard reviews (HRs) and process hazard analyses (PHAs)? The topic is currently the focus of a vigorous debate in the industrial refrigeration industry. While there are advocates for and against employin...
Read More
2021 Tech Paper: Designing Industrial Refrigeration Systems for Full Vacuum – Considerations
Considerations around modes of test and operation that place ammonia refrigeration systems in a vacuum are discussed. A literature review of IIAR publications and general industry recommendations regarding design of pressure vessels and systems for evacuation and operation is presented. Results a...
Read More
2021 Tech Paper: Sustainable Use Cases for Ammonia as a Refrigerant in Residential/Light-Commercial HVAC
A significant amount of research and development has gone into the deployment of ammonia as a refrigerant in air conditioning and heat pump systems, going back to the first half of the twentieth century. This presentation provides an overview of the basic thermodynamic cycles currently in applica...
Read More
2022 Tech Paper: Oil Management Design Considerations for Industrial Transcritical CO2 Systems
Carbon dioxide as a refrigerant is becoming increasingly more popular on a global scale. The industrial refrigeration market is also finding applications for transcritical CO2 systems. Unlike ammonia systems, oil in CO2 systems is typically miscible and can create unique challenges in its managem...
Read More
