The Adaptive Parabolic Control Algorithm (APCA) is a PID replacement algorithm that performs well with nonlinear level controllers, noisy level indicators, and systems that require a rapid response to load changes but a slower response for unit optimization. The APCA reduced compressor amp standa...
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CO2 has gained significant momentum in the North American refrigeration and heat pump industry in recent years, particularly in transcritical applications. Even though CO2 refrigeration technology is already fully mature in terms of component availability, control strategies, and best practices, ...
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CO2 has become a mainstream solution for numerous applications, including industrial and commercial refrigeration, heat pumps, and winter sport venues. Across all these applications, effective superheat control plays a key role in system efficiency and compressor reliability. Superheat varies sig...
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This study experimentally investigates the use of ejectors in transcritical R-744 water-to-water heat pump systems, focusing on adjustable-nozzle control strategies to enhance energy efficiency and operational stability. Although R-744 systems offer several environmental and thermodynamic benefit...
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The industrial refrigeration and heating industries are increasingly affected by the transition to low–global warming potential (GWP) refrigerants and decarbonization initiatives. Consequently, industrial refrigeration and heating applications now often require high suction pressures due to their...
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This paper examines the growing demand for retrofitting in the food and beverage industry, driven by the introduction of new products to the market, regulatory shifts, sustainability goals, and operational modernization. It identifies the key challenges of retrofitting an active production facili...
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Technological innovations have occurred in the movement of palletized goods into, out of, and within refrigerated facilities. Much recent attention has been on technologies such as AGVs (automated guided vehicles), automated pallet shuttles, high-density vertical storage...
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The food and beverage industry is extremely energy-intensive, and there is significant potential in the waste thermal energy generated by its processes. This energy can be utilized to drive lithium bromide water absorption chillers, capable of producing low-temperature leaving evaporator fluids a...
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The CO2 (R744) Simultaneous Chiller Heat Pump integrates cooling, heating, and domestic hot water production into a single, modular system using CO2, a natural refrigerant with an ozone depletion potential of 0 and a global warming potential of 1. By employing parallel VFD-driven compressors (20–...
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All compressors produce some vibration in the connected pipe and tubing, but how much is too much? Excessive vibration can lead to unexpected leaks that can cause hazardous situations and loss of cooling. In many food applications, loss of cooling results in significant product loss in addition ...
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Carbon dioxide (CO2) has emerged as a leading natural refrigerant in commercial refrigeration applications due to its ultra-low global warming potential (GWP of 1), energy efficiency, and alignment with global regulatory phase-down mandates. However, system reliability, charge preservation due to...
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The selection of materials in finned evaporator construction plays a critical role in determining the performance, durability, and overall efficiency of refrigeration systems. This white paper examines the importance of selecting the appropriate material for the construction of finned heat exchan...
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R744 (CO2) industrial air-source heat pumps (ASHPs) can serve as cost-effective and scalable alternatives to conventional heating and cooling systems. Leveraging the unique thermodynamic properties of CO2, a natural refrigerant, these systems deliver high efficiency and flexibility for certain te...
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Air blast freezing systems are among the most widely used technologies for rapidly freezing both packaged and unpackaged foodstuffs. In many food processing facilities, freezing is a bottleneck in the continuous flow production, and thus techniques to assess and improve their thermal performance ...
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This paper explores the potential of integrating CO2 refrigeration systems with energy savings alternatives to maximize sustainability and energy efficiency in agricultural cold storage facilities. With growing concerns over environmental impact and energy consumption, the adoption of ecofriendly...
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As resources get harder and harder to find, we need to explore other ways to help us be effective and make good decisions. For a single plant or a corporation with multiple plants, having good information available helps us leverage our resources for the most impactful decisions. Having an Auto-P...
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Currently, ANSI/IIAR 2 Standard for Design of Safe Closed-Circuit Ammonia Refrigeration Systems (IIAR 2021) requires machinery room emergency mechanical ventilation systems to provide no less than 30 air changes per hour based on the gross machinery room volume. When this emergency ventilation ra...
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The use of carbon dioxide (CO2), especially in industrial refrigeration systems, has received a lot of attention in the last decades. As for any equipment, a correct lubricant choice and a proper oil management strategy are key for the safe, reliable, and efficient operation of refrigeration syst...
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This presentation will focus on the basic understanding of water treatment and the involvement of industry that is required to extend the life of the equipment. In order to properly protect the asset from a water treatment perspective, industry needs to be more involved and educated. This present...
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You may be familiar with the quote, “Those who do not learn from history are doomed to repeat it.” Learning from others’ mistakes can be a game-changer in the world of ammonia refrigeration. This paper contains a collection of accounts of ammonia releases and interesting details from each inciden...
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Author: Paul Danilewicz, P.E., Santosh Yarlagadda Enerflex Energy Systems, Inc. Houston, Texas
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Large industrial refrigeration systems often suffer from operating instabilities caused by refrigerantliquid feed controls that are poorly engineered or improperly tuned. A strategy that requires more sophisticated controls potentially addresses operating instabilities but may introduce other cha...
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CO2 is an emerging refrigerant in North America, but identifying its suitable applications can still be challenging. In Europe, CO2 has been used in heat pumps for several years. This paper discusses the experience of using CO2 in heat pumps in Europe, giving the basics of its use as a refrigeran...
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Since the advent of process safety, the process hazard analysis (PHA) method of choice across the refrigeration industry has been the what-if/checklist technique. Over the last 20 years, many companies’ and industries’ hazard assessment methods have matured. While the hazard and operability (HAZO...
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The need to decarbonize industrial facilities is greater than ever. One technology that will play a large role in reducing carbon emissions is industrial heat pumps. With hundreds of different combinations of industrial heat pump systems, engineers and designers need to understand which technolog...
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Herein, the application of a rotary gas pressure exchanger (PX) for increasing the efficiency of transcritical CO2 refrigeration systems is examined. The PX uses high-pressure discharge from a condenser/gas cooler as a motive fluid to compress the low-pressure flash gas with minimal external ener...
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This paper describes enhanced and integrated carbon dioxide refrigeration systems that can improve yearly energy figures when compared to traditional flash-gas bypass (FGB) solutions, making CO2 an attractive option for industrial refrigeration in some regions.
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Over the last several years, facilities covered by the Environmental Protection Agency’s Chemical Accident Prevention Provisions, otherwise known as the Risk Management Program, have beenforced to navigate unpredictable and frequent shifts in policy. This paper is intended to familiarize readers ...
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This paper demonstrates how evaporative condensers can be used as low-stage de-superheaters to improve the efficiency of two-stage ammonia refrigeration systems. The high discharge temperatures generated by ammonia compressors can help reject heat to ambient heat sinks, thereby reducing the load ...
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Before companies can report on progress toward sustainability goals, they need to establish a baseline. This paper outlines fundamental best practices for creating a useful energy baseline: defining the metrics upfront, normalizing the data, setting up real-time monitoring, and submetering specif...
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Ammonia refrigeration system managers are looking for more useful information regarding risk mitigation and compliance because they need to determine whether components are fit for service or vulnerable to damage, and when to act. Insulated piping is subject to corrosion under insulation (CUI), b...
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This technical paper addresses potential business risks associated with the Hazardous Waste Operations and Emergency Response (HAZWOPER) standard for ammonia refrigeration contractors when used for repairing leaks in ammonia refrigeration systems. The definitions of an incidental leak and leaks r...
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The requirements for determining the capacity of vapor service pressure-relief devices applied to partially liquid-filled ammonia vessels/equipment and discharging to the atmosphere, as well as liquid service relief devices completely filled with non-volatile liquid (e.g., compressor oil) dischar...
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Reducing the charge in ammonia refrigeration systems is becoming increasingly important. However, reduction must be achieved without compromising the efficiency of the ammonia refrigeration system.
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Intelligent CO2 compressors and ejectors are emerging as highly promising solutions for industrial refrigeration systems. This publication highlights their expanding capacity and scale, demonstrating their suitability for various applications, including cold storage facilities, distribution cente...
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Decarbonization is a crucial process in the effort to mitigate the effects of climate change. Considering this aim, efficient energy utilization is also imperative for sustainable and cost-effective operations in dairy plants. In general, the refrigeration system rejects heat to the atmosphere on...
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This paper provides an overview on the basics of carbon counting and how they may apply to carbon counting within the cold storage industry. It will also cover opportunities to take advantage of newer technologies available to improve the accuracy of carbon reporting data, and the ability to gene...
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Chidambaram Narayanan, External Consultant Joel-Steven Singh, Senior Engineer AFRY Switzerland AG
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The rise of automation brings new cybersecurity threats to heavy industries. Cybersecurity attacks like ransomware, malware, and phishing are becoming commonplace and more sophisticated as they continuously evolve and change. This paper reviews the risks and tactics of the most common classes of ...
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Transcritical CO2 heat pumps are emerging as a viable alternative to synthetic air- or water-source heat pumps, and they present an opportunity for electrification while eliminating the need for refrigerants with high global warming potential. The purpose of this technical paper is to assess the ...
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This paper presents an objective analysis of the Federal Environmental Protection Agency’s (EPA’s) enforcement of ammonia refrigeration facilities across America conducted using hundreds of publicly available independent inspection reports dating from 2006 through 2021...
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Generally, safety standards for refrigeration systems require the placement of at least one overpressureprotection device on all carbon-dioxide (R-744) systems as well as on vessels manufactured in accordance with the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Secti...
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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....
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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...
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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.
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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 ...
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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 ...
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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...
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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...
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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,...
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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 ...
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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...
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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...
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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 ...
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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...
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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...
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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...
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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...
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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...
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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...
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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...
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