2004 IIAR Technical Papers
   Orlando, FL
  26th Annual Meeting

Ammonia Leak Detection in Refrigeration Systems
Author: Eleny Fotis

Codes and standards require that ammonia refrigeration systems be monitored for leaks. Various technologies can detect ammonia, including electrochemical, infrared, solid state, polymer thin-film capacitive, and charge carrier injection, and these all have unique strengths and weaknesses. Recognizing that refrigerated areas can present challenging operating conditions to ammonia sensors, end users must be careful to choose the appropriate technology to suit their particular application. Changing temperatures and humidity levels in the application/process will sometimes affect the ammonia level or the lifetime of the sensor. Other gases and odors plant may cause the sensor to respond and can lead to unnecessarily and costly false alarms. How can end users decide what to do? The paper will review the pros and cons of each technology, and discuss factors that influence sensor effectiveness and sensitivity.
Integrating Advanced Controls into Plant Processes and Management Programs
Author: Paul H. Stiller, P.E.

A variety of recent technical developments in refrigeration control systems promise to improve efficiency, effectiveness and reliability. Utility management can now be an integral part of the manufacturing process. Moreover, sensor technologies allow more effective maintenance action planning. Further, operators can make decisions based on real-time information. Cooling energy can be managed like other factors of production. End users have an opportunity to control and fine-tune systems as never before. They enjoy the power of modern information technology that will allow energy costs to be managed as part of the manufacturing process. This paper discusses the opportunities and then presents specific examples of information and automation technology applications to refrigeration plant-process and management in manufacturing.
Operating Procedures and Training
Author: Lawrence E "Tex" Hildebrand, Vern M. Sanderson and Michael D. Axthelm

It can be very difficult to maintain a good balance between simplicity and thoroughness in standard operating procedures (SOP) descriptions, and in operator training as well. Sometimes, SOPs can end up so simple that they are dangerous to the inexperienced operator, or alternatively, so thorough that they aren’t practical for use. This paper provides insight into the development and practical application of SOPS and the operator training programs. The paper adopts a novel approach in which operating procedures are discussed from four viewpoints: a consultant, a contractor, an end user, and a regulatory auditor. The paper reviews techniques to reduce costs, increase safety, streamline operations, and help improve the retention of operators. The paper also provides suggestions on what the content of SOPS should be, including recommendations on levels of operational precision, what should be included, and what should not be included. The discussion of SOPs segues naturally into a discussion of training topics. Finally, the paper provides practical recommendations on how, when, where, who, and how much to train that attendees can implement immediately.
Understanding Mechanical Integrity Inspections: What, When, Who, Why & How
Author: Christopher Ciucci

“Mechanical Integrity Inspection” is perhaps the most ambiguous term used in the ammonia refrigeration industry. This paper provides a common sense definition of the term and describes a simple structured approach to such inspections that answers all of the basic questions surrounding this issue: What should be included in a Mechanical Integrity Inspection? How often does a Mechanical Integrity Inspection need to be done? Who is qualified to perform a Mechanical Integrity Inspection? Why is a Mechanical Integrity Inspection important? How do we develop and implement a Mechanical Integrity Inspection program?
Mechanical Integrity for Ammonia Refrigerating System Piping and Pressure Vessels
Author:  Ronald A. Cole, P.E. and Godan Nambudiripad, P.E.

Mechanical integrity is an issue that is not universally understood within the ammonia refrigeration industry The guidance currently available to our industry on this issue seems to be based on the experience of the chemical and petrochemical industries. There is little doubt that our industry can improve on this situation, especially for piping and vessels. The paper includes a case study in which the authors dealt with all of the practical issues associated with creating and developing a mechanical integrity program from the ground up. The authors then refine the method using a rational approach, and share major parts of it. The paper shows a cost-effective mechanical integrity program tailored specifically to ammonia refrigeration systems, focusing on critical and high-risk areas.
An Overview and Comparison of Refrigeration Model Codes on Select Topics
Author: Eduardo A. Ford, P.E.

In recent years our industry has seen an increase in the number of significant changes in design requirements for relief system design, hydrostatic relief, emergency diffusion and machinery room ventilation, to mention a few. The UMC, IMC, ASHRAE 15 and IIAR 2 at times seem inconsistent, at times, contradictory. The primary objective of a code should be straightforward; ie., a series of specific regulations mandating the design, fabrication, installation and operating practices that will prevent loss of life and damage to property caused by failure of a refrigeration system. This paper compares how the above topics are addressed in the commonly referenced refrigeration codes, and offers some suggestions as to areas of commonality and recommendations for unification attempts among these bodies.
Pressurization of Critical Process Areas
Author: Bruce A. Paulson

Food products are susceptible to contamination from many sources. For years, one possible source, airborne contamination, had been ignored and little importance placed upon it. However, the air in a critical process area, which comes into direct or indirect contact with the food product, has been proven to be a possible vehicle for the spread of spoilage and pathogenic organisms. This can result in product returns, loss in customer acceptance, and increased regulatory surveillance. Positive pressurization counteracts the infiltration of potentially contaminated air from entering a critical process area from adjoining less critical areas and therefore can reduce the risk of airborne product contamination.
Energy Cost Trends and Energy Cost Reduction Strategies for Food Processors and Refrigerated Warehouses
Author:  Elizabeth T. Lowe

Current pricing trends for natural gas and electricity do not bode well for large energy consumers. Contrary to previous trends, prices for both fuels now peak in the summer in some areas, hurting summer-peaking customers such as food processors and cold storage facilities. Our industry is greatly concerned that these trends will affect its overall viability and competitiveness. This paper reviews strategies for determining the best way to manage energy costs from both the supply and the demand side. Finally, it describes how to dovetail these supply and demand strategies to maximize the leverage each customer has with its utility providers.
Practical Considerations for Variable Frequency Drives in Ammonia Refrigeration
Author:  Peter A. Lepschat

Achieving reliable, cost effective, and energy efficient operation of systems with variable frequency drives (VFDs) has sometimes been difficult. Over the past few years, various studies have proven the power saving potential of VFDs. The cost of VFDs has dropped steadily and their reliability and flexibility has increased dramatically. Accurate information on how to apply VFDs correctly in our unique industy can be hard to get, however. This paper outlines factors designers need to consider during the design, installation, setup, operation, and maintenance phases of a VFD project. The paper discusses equipment sizing and location, drive load calculations, driven motor protection, power quality problems, control system interface, and control strategies. Finallv, the paper provides application recommendations based on past experience.
CO2 in Subcritical Refrigeration Systems
Author: Niels P. Vestergaard

Within industrial refrigeration, interest in CO2 is growing. Application of subcritical CO2 in refrigeration is far from being a new idea, but its use can present challenges in design, operations, and maintenance. In many aspects, CO2 is different from other common refrigerants like ammonia or R- 134a. This paper examines these differences, and provides a discussion backed up by theoretical knowledge combined with practical experience and laboratory tests.

2004 Programa en español

Purgadores de gases
Author: Ernesto Rodriguez

La necesidad del ahorro de energia es importante en la actualidad. En este articulo se describen las ventajas, aplicaciones y funcionamiento del purgador de gases no condensables. AI comprender estos puntos se obtendrá una óptima operación del purgador y un incremento de eficiencia en la operación de los sistemas de refrigeración. La aka temperatura de condensación es una de las causas de varios problemas en el sistema de refrigeración. AI entender estas causas se podrá prevenir e incrementar la eficiencia del sistema. Otro punto muy importante es entender como trabaja el purgador de gases no condensables. Una inadecuada instalación ocasiona un funcionamiento inadecuado del equipo y como consecuencia una perdida de eficiencia en el sistema de refrigeración.
Análisis y simulación de un nuevo tipo de absorbedor para sistemas de refrigeración por absorción agua - amoniaco
Author: Rafael Lincoln Pratts Milanes and J.T.V. Pereira

Historicamente los sistemas de refrigeración por absorción agua-amoniaco han usado intercambiadores de calor de casco y tubo de gran porte, ocupando un espacio fisico considerable y con costo de fabricación elevado. Estas limitaciones pueden ser superadas usando absorbedores resfriados evaporativamente. Este trabajo muestra las evaluaciones realizadas sobre un absorbedor evaporativo desde el punto de vista termodinámico, de operación real y de simulación matemática. El estudio fue desarrollado sobre un prototipo experimental instalado en un sistema de absorción para la fabricación de hielo, lo que también permitió determinar su compotfamiento durante el proceso de deshielo. Los resultados mostraron un buen compotfamiento de este tipo de absorbedor.
Una etapa contra dos etapas, Cuál?
Author: Juan Manuel Castillon Rios

Durante muchos años, los ingenieros de la industria constantemente hablaban de las ventajas relativas de los sistemas de dos etapas contra los sistemas de una etapa de refrigeración en sistemas centrales. Hoy en dia, sin embargo, las consideraciones pertinentes siguen siendo pasadas por alto. Los ingenieros deberian estudiar el sistema completo utilizando los diagramas de Mollier para determinar cuales factores son relevantes y que in fluyen considerablemente en la selección del sistema de compresión en particular. Las consideraciones que se tienen que observar son, el tipo de compresor, las condiciones de funcionamiento del sistema, el condensador, los parámetros de operación y la e ficiencia del sistema. La finalidad de esta ponencia, es ilustrarles como estos factores pueden afectar las decisiones de ingenieria hechas en el diseño o expansiones de un sistema de refrigeración.
Aplicación y diseño de sistemas de refrigeración industrial
Author: Ricardo Mardones

El objetivo principal de este trabajo es el de establecer criterios en conjunto para tener una mejor visión de los requerimientos de refrigeración en America Latina. Los siguientes topicós serán presentados:
Cálculos de carga
Criterios de selección de sistemas
Consideraciones para la selección de equipos
Tipos de sistemas de refrigeración