Lesson 1 - Physical Properties of Refrigerants
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
– Determine compressor discharge temperature, compressor volume displacement, superheat, subcooling, and total heat rejection in the condenser,
– Explain the purpose and methods of liquid subcooling.
Lesson 2 - Refrigerant Classification and Applications
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
Lesson 3 - Refrigerants and the Atmosphere
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.
Lesson 4 - Refrigerants and the EPA
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.
Lesson 5 - Refrigerant Filters and Driers
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.
Lesson 6 - Tools & Procedures for Working with Refrig.
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.
Lesson 7 - Refrig. Oils, Oil Maint., & Service Procedures
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.