2020 IIAR Technical Papers
Virtual Conference
42nd Annual Meeting

CFD Simulation of NH3 Release and Detection in Refrigerated Spaces (Results of the IIAR/ARF Research Project)
William Greulich, Kensington Consulting

This paper examined the results of a computational modelling study of ammonia release in three refrigerated spaces to evaluate potential detector performance. Come see why detector response time data is crucial in assessing the performance of single-detector placement and guiding the choice of detector positioning where ammonia from a leak is most likely to accumulate.
Methods for Saving Energy in Cold Storage Warehouses
Author: Caleb Nelson,

This paper aims to enable end users, engineers, operators, and manufacturers to understand and improve the energy efficiency of cold storage warehouses. Warehouse owners and operators are experts in optimizing the logistical operation of their facilities, and some know to optimize energy performance by influencing the measure and timing of demand on refrigeration systems. However, understanding the complexity of design and operation of the refrigeration system itself offers a further opportunity for energy savings that remains untapped for many. 
Transcritical Carbon Dioxide and Ammonia: Energy Efficiency and Basic Capital Cost Comparison for Industrial Refrigeration Systems
Author: Giacomo Pisano

Carbon dioxide (CO2, R744) has for years been used as an alternative to hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) in numerous refrigeration market sectors due to its environmentally friendly characteristics and its performance in many applications. But until quite recently, the lack of large-scale transcritical CO2 components has limited the application of carbon dioxide in the industrial refrigeration segment, leaving anhydrous ammonia (NH3, R717) as the preferred choice for larger duty applications (e.g., >125 TR or 1,500 kBtu/h).

In recent years, however, significant technological advances—such as large-displacement, sixcylinder compressors and next-generation ejectors—have enabled cost-effective transcritical CO2 solutions for industrial refrigeration. This paper compares the performance among various CO2 and ammonia technologies applied to an industrial CO2 refrigeration system with a capacity of 1,000 TR (12,000 kBtu/h).

Proper Installation and Maintenance Practices for Variable Frequency Drives
Author: Paul Jasczynski

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.

When operating, VFDs generate heat, and the output voltage waveform is not a true, clean sinewave. These characteristics present challenges when installing a VFD. However, following a few proper installation practices can help ensure successful operation. Most VFDs fail because of an improper installation and not because of a poor-quality product.

The following seven recommended practices will help ensure a successful VFD installation and optimal equipment life.
Development of a Mechanical Insulation Installation Guideline for Refrigeration Applications
Author: Gordon H. Hart

Pipe and equipment at refrigerated food-processing and distribution facilities are thermally insulated to reduce energy use, control the refrigeration process, and prevent condensed water from dripping onto the outside surface of the insulated items. A major challenge for these systems is water vapor intrusion into the insulation materials, with subsequent condensation to water and/or ice that greatly compromises the insulation’s thermal performance. Severe corrosion of the steel surfaces beneath the insulation, known as corrosion under insulation (CUI), also sometimes results, eventually requiring pipe and equipment replacement. In this IIAR/ARF-sponsored research project, the principal investigator (PI) sought to identify materials, processes, and practices that contribute to greater longevity of these insulation systems. The PI examined insulation removal at older facilities and new insulation installation at those older facilities and at newly constructed facilities. While the PI concluded that the industry is doing a much better job of insulating today than it did a quarter of a century ago, following some insulation installation guidelines could improve the insulation systems’ longevity and performance while minimizing CUI.
Case History: A Study of Incidents in the Ammonia Refrigeration Industry
Author: Peter R. Jordan
In June of 2005, the author initiated a project to collect data related to ammonia incidents using information from publicly available sources. For the past 14 years, the data have been input into an Excel spreadsheet every day. This information was analyzed and compared with historical incident data available from the U.S. Environmental Protection Agency’s Risk Management Plan database and a 2008 IIAR survey. The hope is that analyzing these incidents will highlight industry policies and practices that can prevent and/or mitigate the consequences of future incidents in the ammonia refrigeration industry, thereby improving overall industry safety.
Taking Your PSM Program to the Next Level: Establishing an Evaluation System

Author: Linda McDaniel

Process safety management (PSM) is an “evergreen” process requiring consistent monitoring to ensure compliance. An evaluation system of the various audit/inspection programs is a good tool for monitoring the pulse of the PSM program and providing a gap analysis report that can be communicated throughout the organization. An evaluation system also helps with accountability in completing recommendations in a timely manner, provides a tool to rank open recommendation priorities from the various audit/inspection programs and keep up with annual requirements, and allows for continuous improvement of the PSM program. 

This paper will review steps for establishing a grading system to score the triannual compliance audit, five-year process hazards analysis (PHA) revalidation, and five-year mechanical integrity (MI) inspections. It also provides a means for tracking items such as standard operating procedure (SOP) certifications, training, and maintenance inspections/tests (i.e., annual visual inspections and vibration and oil analyses) required annually under current IIAR standards.
Permanent Refrigeration Plant Performance Optimization Using Continuous Real-Time Analysis
Author: John Clark and David Blackhurst

The data-gathering, plant-modeling, and analysis delivery system described in this technical paper uses the concept of a “digital twin” to confirm refrigeration plant operation is optimized, given the system type, components used, and prevailing operational conditions. Where this is not the case, the digital twin can offer insights into how to rectify the situation and highlight the ongoing cost of the prevailing situation. It can be applied to any type and size of refrigeration system to deliver significant efficiency, operational, and behavioral improvements.

Commercial/Food Retail

Hot Gas vs. Electric Defrost for Standard Commercial Refrigeration Systems: An Energy Comparison

Author: Danny Halel

In commercial refrigeration systems used for supermarket refrigeration, eliminating significant ice and frost build-up on the equipment is sometimes necessary (Figure 1). In these systems, gas defrost systems were thought to be less expensive to operate from an energy standpoint because gas systems can utilize refrigerant from compressors that are already running. This paper highlights some of the significant variables involved with defrosting commercial refrigeration systems and provides insight into how much energy will be used in a typical electric system versus a typical gas defrost system.

Equipment factors that will be considered include compressors, pan heaters, and coil heaters. The result is a percentage increase or decrease in energy costs based on location. The systems compared are equipped exactly the same and located in 12 cities across the United States. 

A trend exists in the refrigeration industry to move to a “demand defrost” system that activates only when the coil or system requires. As of the writing of this paper these types of systems have been available for about five years, but not enough data are available to prove them to be a consistent, reliable technology for commercial refrigeration systems
Assessment of Lubricants for Hydrocarbon Refrigeration Systems
Glenn D. Short

Hydrocarbon refrigerants are increasingly recognized for their ozone-friendly characteristics; zeroto-negligible global warming potential (GWP); and, in some applications, a performance benefit versus other refrigerants. Hydrocarbon refrigerants may be used in applications ranging from small domestic appliances and residential air conditioning to large industrial systems. As a result, the use of refrigerants such as R-290, R-600a, and R-1270 are finding increased use. 

Certain properties of refrigerant-lubricant mixtures are essential to the design, efficiency, and performance of compressors and the refrigeration cycle. An examination of a lubricant’s chemistry, miscibility, solubility, and viscosity in the presence of a given refrigerant helps system engineers find the best overall balance of compatibility, lubricity/load-carrying performance, and system performance. This paper presents data for systems employing various hydrocarbon refrigerants with mineral oil and synthetic lubricants to investigate potential overall performance benefits.
Low Head Pressure Operation of Commercial Systems
Author: Dustin Lilya

Commercial refrigeration compressors account for approximately one-third of the energy a grocery store consumes. Commercial systems in the United States do not typically utilize liquid refrigerant pumps and instead use system pressure to feed liquid to the cases. The high-side liquid pressure is often a limiting factor for low head pressure operation. Retrofitting existing refrigeration systems with liquid pumps and other components is possible to allow for operating systems with a significant reduction in minimum head pressure operation. This paper will explore a common rack system design, break down the components (beyond liquid pumps) that are limiting factors for low head pressure operation, and provide a methodology to establish operational boundaries for low head pressure operation based on the common refrigeration system components’ limiting factors.
Analysis of Package Chiller Systems: Comparison of Natural (NH3  and CO2) and HFC Refrigerants
Author: John D. Collins

This technical paper evaluates criteria for selection of chiller systems in an ice rink application considering three refrigerants: ammonia (NH3 R-717, carbon dioxide (CO2) R-744, and hydrofluorocarbon/hydrofluoro-olefin (HFC/HFO) blend R-448A. System performance based on calculated equipment operating data, analyzed with bin weather data, is presented for similar systems using each refrigerant. Other factors involved in refrigerant selection are presented, including regulatory issues, safety, operations, and costs. A comparison of the performance with each refrigerant is presented.

2020 Programa en español

Distritos térmicos con amoníaco en Colombia, barreras técnicas y tecnológicas
Author: Bolívar Andrés Monroy Matallana

Los distritos térmicos como soluciones distritales de suministro de energía térmica para enfriamiento o calefacción, son oportunidades de crecimiento del mercado de los sistemas de refrigeración con amoniaco, ya que estos pueden ser usados en aplicaciones residenciales, comerciales e industriales. Sin embargo en países como Colombia, existen barreras técnicas, legislativas y sociales que estos sistemas deben superar para apoyar de manera efectiva las metas de reducción de impacto ambiental por el uso de energía asociada a sistemas de refrigeración y climatización.
Comparación del Costo Operativo entre Sistemas del tipo CO2  Transcrítico y de Recirculación con Amoníaco para Almacenes de Refrigerado
Author: Chris Herzog Peter Lepschat

This paper will analyze the operating costs of two similar cold storage facilities: One with a modern and efficient recirculated ammonia system, the other with a transcritical CO2 system. The analysis will delve deeper than just utility costs: maintenance, personnel, compliance, insurance, water, chemical and drainage costs will be considered, with an eye to demonstrating the true cost of ownership of the two system types.
Aplicación de las normas ANSI/IIAR 2, ANSI/IIAR 6 y regulaciones nacionales para un sistema de refrigeración de una planta de beneficio bovino en Colombia
Author: Bolívar Andrés Monroy Matallana

Las condiciones del mercado nacional han cambiado y exigen el cumplimiento de normas y estándares donde las características de los productos bovinos exigen el uso de tecnologías, donde la sanidad y la eficiencia energéticas son criterios de selección de la solución. En este documento se mostrarán las condiciones de diseño y mantenimiento para un sistema de refrigeración de circuito cerrado en Colombia, así mismo se presentarán los criterios que debe cumplir dicho sistema respecto a los estándares ANSI/IIAR 2 y ANSI / IIAR 6. Por último, se mostrará el sistema nacional de beneficios tributarios y fiscales que puede aprovechar el sector para ejecutar los cambios tecnológicos con retornos de inversión más cortos.