Refrigerants and Refrigerant Oils

Table of Contents

Chapter 1: Physical Properties of Refrigerants

Topics: Pressure-temperature relationship; Enthalpy; Pressure-enthalpy diagrams; Liquid subcooling

Learning Objectives:

• Explain the relationship between pressure and boiling point in a liquid.
• Define the term enthalpy, and differentiate between the enthalpy of saturated liquid, the enthalpy of evaporation, and the enthalpy of saturated vapor.
• Use a P-H diagram to show the process of evaporation, compression, condensation, and liquid metering.
• Calculate the compression ratio, refrigerating effect, refrigerant flow rate, heat of compression, compressor horsepower, and coefficient of performance for a system.
• Determine compressor discharge temperature, compressor volume displacement, superheat, subcooling, and total heat rejection in the condenser, using a P-H diagram.
• Explain the purpose and methods of liquid subcooling.

Chapter 2: Refrigerant Classification and Applications

Topics: Refrigerant identification; Refrigerant/oil mixtures; Common refrigerants and mixtures; Ammonia; Safety; Handling containers

Learning Objectives:

• Identify several properties of the ideal refrigerant.
• Explain the ASHRAE standard for refrigeration identification.
• Discuss in detail some common refrigerants in use today-their advantages, disadvantages, characteristics, and applications.
• Define the terms blend, fractionation, temperature glide, and azeotrope.
• Describe how refrigerants are classified for safety purposes.
• Explain the safety precautions that must be taken when handling and storing

Chapter 3: Refrigerants and the Atmosphere

Topics: Ozone hole; CFCs and ozone; Greenhouse effect; Alternative refrigerants; Changes in servicing, installation practices

Learning Objectives:

• Explain how CFCs deplete the ozone layer and contribute to the greenhouse effect.
• Explain how refrigeration system servicing procedures have changed in response to the discovery of ozone depletion.
• Name the "three Rs" and define each term.
• Identify several ways in which good installation practices can prevent refrigerant leaks.

Chapter 4: Refrigerants and the EPA

Topics: Clean Air Act; Section 608 overview; Refrigerant recovery; Releases and leaks; Enforcement; Logs; Certification testing; Purchasing refrigerant

Learning Objectives:

• Name some of the steps being taken by the United States government to control the depletion of stratospheric ozone.
• List the five main elements of the EPA regulations concerning recycling, emission reduction, and disposal.
• Contrast active and passive recovery equipment.
• Define the three types of refrigerant releases permitted by EPA regulations.
• List the reports you should keep concerning refrigerant purchase and use.
• Explain the levels of technician certification.

Chapter 5: Refrigerant Filters and Driers

Topics: System contaminants; Types of filters, driers, and filter-driers; Desiccants; Strainers; Suction filters; Installation precautions

Learning Objectives:

• List the contaminants that can infiltrate or form within a refrigeration system.
• Describe the various types of filters, driers, filter-driers, and strainers used in mechanical refrigeration systems.
• Distinguish between absorption-type and adsorption-type desiccants.
• Explain the importance of proper location when installing filters, filter-driers, and strainers.
• List the important factors to consider when selecting a filter-drier.
• List several safety precautions to follow when working with filter-driers.

Chapter 6: Tools & Procedures for Working with Refrigerants

Topics: Leak detection; Vacuum pump; Gauge manifold; Checking refrigerant charge; Evacuation and dehydration; Charging; Recovery/recycling

Learning Objectives:

• Describe the various methods of locating leaks in a refrigeration system.
• Explain how to connect a gauge manifold to a system and how to remove air from the manifold.
• Explain how to check the refrigerant charge in a system.
• Name and describe the two methods of evacuating and dehydrating a refrigeration system.
• Describe the procedures for vapor charging and liquid charging a system.
• Identify and explain the various methods of adding the correct amount of refrigerant to a system.
• Contrast active and passive refrigerant recovery.

Chapter 7: Refrigerant Oils, Oil Maintenance, & Service Procedures

Topics: Oil properties; Compressor lubrication; Oil-related problems; Oil separators; Contaminants; Maintenance and servicing; Adding and removing oil

Learning Objectives:

• Explain the purposes oil serves in a refrigeration system.
• Define the following properties of oil: stability, viscosity, miscibility, floc point, and flash point.
• Name the two broad categories of oils and the sub-categories of each.
• Explain how oil becomes mixed with the refrigerant and the problems its presence can cause in a refrigeration system.
• Describe the function of an oil separator.
• List several problems that can be caused by water in a refrigeration system.
• Describe the procedures for checking oil level and adding or removing oil.

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