Intermediate Systems for Operators

A web-based course conducted by the Industrial Refrigeration Consortium

Industrial Refrigeration Consortium www.irc.wisc.edu

Intermediate Refrigeration Systems for Operators

This class is designed to build upon and extend the skills developed in the introductory class. This class furthers an operator's understanding of ammonia refrigeration and reinforces many of the duties required of an operator. It is not intended to replace plant-specific operation training. Rather, this course strengthens the operator’s understanding of ammonia refrigeration theory making them better equipped to receive plant-specific training. The course material is suitable for anyone who has successfully completed the introductory course.

A typical course outline is provided below, but can be modified to meet your plant's/company's specific training needs. The course is taught in ten sessions that are 2 hours in length. If desired, an examination can be administered to participants upon completion to validate their comprehension of the material.

Advantages of E-Learning

In its quest to provide companies with affordable and unified training for operators, the IRC has refined its development of web-based training. Some of the advantages include:

• Training is delivered live by qualified instructors. • A uniform training program can be delivered to all operators across multiple plants. • Eliminates travel costs for both students and instructors. • Can be tailored to your company’s training needs. • Session can be recorded and played back at a later date. • Students have multiple ways to interact with instructor both during and after class. • Homework and exams are to verify their level of comprehension.

All web-based courses offered by the IRC feature 1 or 2 instructors providing live audio feed over phone lines while participants view slides, documents, images and animations over their internet connection. Participants can interact with the instructors both on-line and by telephone during the course or can contact the instructors after the session has ended. Most courses are taught in 2 to 4 hour segments over several days. This allows participants stay productive within their plants since there is no off-site travel.

These courses are intended to build operator’s understanding of refrigeration theory and fundamentals. Our experience has shown that operators with this sounds knowledge make better decisions in their plants-particularly during upset conditions. This foundation of knowledge also makes operators better equipped to receive plant-specific procedure training as required by PSM.

Course Outline Refrigeration Components: Valves/Metering Devices

Refrigeration Systems Review • Solenoid valves • Check valves • Single stage systems: direct expansion, • Stop valves flooded, liquid overfeed • Expansion valves: hand-expansion, • Multi-stage Systems: direct, indirect thermostatic Loads • Modulating valves • Regulators • Temperature requirements • Actuating methods (direct-acting, pilot- • Envelope loads operated) • Product loads • Installation considerations • Internal loads • Service considerations: packings, stem • gains lubrication, valve exercising • overview • Sensible & latent loads Refrigeration Components:

• Infiltration loads - theory vs. real-world • Reciprocating • Rules-of-thumb • Screw (single/twin) Assessing System Performance • Rotary • Duty: high-stage, booster • Basic vapor compression cycle • ratings: capacity, power, • Performance measures efficiency • Benchmarking • Capacity control/unloading • Pressure- diagrams • Variable volume control • Influence of head pressure, suction • Methods of oil cooling pressure, subcooling & superheat o Thermosiphon • System balance o Liquid injection Refrigeration Components: Condensers o -cooled

• Types: water-cooled, evaporative Refrigeration Components: Vessels & • Performance characteristics Accumulators

• Wet/dry operation • Types: high-pressure receiver, • Piping considerations (traps, vent line sizing, thermosiphon, low-pressure accumulator, drainers) flash intercooler • Fan alternatives - single speed, two speed, • Configurations: horizontal or vertical and variable speed • Proper practices for system integration Refrigeration Components: • level control (floats, capacitance probes) • Evaporator types - Plate-fin, • Influence of oil on level controls & floats o Plate-fin o Sprayed glycol Refrigerant Management Issues

Shell-and-tube o • Transfer systems - what are they and why o Plate-and-frame are they needed? Ice builders o • Gas pumping • Refrigerant feed • Mechanical pumping Top-fed o • Advantages/Disadvantages o Bottom-fed o DX, Flooded, Overfeed Purgers and Purge Systems

• Defrosting • Non-condensables o Methods • Determining presence of non-condensables o Influence on head pressure • Consequences of non-condensables o Influence on compressor loading • Purge locations and techniques o Do I need high head pressure for • Importance of muli-point purging defrosting? • Purger operation • Installation considerations Insulation Systems Operational Issues

• Insulation system types and alternatives • Methods for adjusting valves • Thickness requirements o What, where, why? • Vapor and considerations o Hand expansion valves • Sheathing and jacketing o Thermostatic expansion valves • PM & Inspection guidelines o Back-pressure regulators • Estimating quantity of refrigerant released Pumps during an incident • Refrigerant Pumps • Estimating residual refrigerant inventory after o Pump types and performance curves pump-out o Net positive suction head required • Techniques for safely charging systems

o Net positive suction head available Incidents o Refrigerant pump cavitation (causes, diagnostics, and cures) • Why do they occur? • Secondary Fluid Pumps • How can they be minimized? o Types & performance • Overview of incident investigation o Influence of fluid selection o When is it required? o Influence of operating temperature o What is required? o Relationship to PHAs Maintenance Overview Troubleshooting • Oil draining o Where, when, why? • What are the causes of high head pressure? o Techniques for safe draining What are the cures? o Attire (personal protection) • Why can't I get my evaporators defrosted? • Cleaning strainers How often should I defrost? o Where, when, why? • What causes high-level alarms and shut- o Techniques for safe pump-out downs? o Attire • Hydraulic shock - what is it? How and why • Testing ammonia for water do you want to prevent it? o Where, when, why? o Sample collection

Process Safety Management

• Process safety information • Mechanical integrity o Visible inspection techniques o Inspection intervals • Management of change

Safety Systems & Equipment

• Ammonia detectors o Types o Proper locations o Testing & calibration requirements • PRVs & relief piping o Types o Code requirements o Inspection intervals

Web-based courses currently offered by the IRC

• Advanced Refrigeration Systems for Operators • Ammonia Awareness Training for Employees • Intermediate Refrigeration Systems for Operators • Introduction to Refrigeration Systems for Operators • Overview of Ammonia Refrigeration Systems

For more information, contact the IRC at [email protected].

Industrial Refrigeration Consortium 1415 Engineering Drive Suite 2342 Madison, WI 53706

Toll-free: (866) 635-4721 Local: (608) 262-8220 Fax: (608) 262-6209