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Learning Objectives
Information in this chapter will enable you to:
Recognize the effect of halogenated refrigerants
on the ozone layer.
Summarize Environmental Protection Agency
regulations governing refrigerants.
Differentiate between CFC, HCFC, HFC, and
blended refrigerants.
Identify refrigerants according to their series number
and cylinder color code.
Interpret pressure-temperature curves, pressure-
enthalpy tables, and pressure-enthalpy diagrams.
Summarize the properties and common applications
of different refrigerants.
Identify which types of refrigerants are compatible
with which lubricants.
Technical Terms
azeotropes
chlorofl uorocarbons (CFCs)
Clean Air Act
coeffi cient of performance
(COP)
dielectric strength
Environmental Protection
Agency (EPA)
expendable refrigerant
expendable refrigeration
system
fl ammability
fl ash point
fl oc point
fractionation
freezant
fully halogenated
global warming potential
(GWP)
hydrochlorofl uorocarbons
(HCFCs)
hydrofl uorocarbons (HFCs)
near-azeotropes
ozone depletion potential
(ODP)
pour point
pressure-enthalpy diagram
pressure-enthalpy table
pressure-temperature curve
refrigerant blends
refrigeration lubricant
temperature glide
toxicity
viscosity
wax separation
zeotropes
Review of Key Concepts
Reviewing these concepts from earlier chapters will help
you understand new concepts presented in this chapter:
A refrigerant changes phase from liquid to vapor
to absorb heat inside a conditioned space and
from vapor to liquid to release heat outside of
a conditioned space. (Chapter 2)
For most substances, heat energy added or removed
while the substance is at its boiling point is used to
change its state, so its temperature does not change.
(Chapter 1)
The higher the pressure is, the higher the
temperature needed to bring about a state change
and vice versa. (Chapter 1)
In a saturated condition, all of a substance’s
molecules have been vaporized that can be
vaporized under the existing conditions of pressure
and temperature. (Chapter 1)
Most refrigeration systems use oil to lubricate the
compressor and other moving parts. (Chapter 2)
Introduction
There have been many attempts to fi nd a refriger-
ant that is effective, safe, cost effi cient, and environmen-
tally harmless. In the late 1800s, inventors used water and
ammonia as refrigerants in absorption systems. In the early
1900s, the fi rst electrically powered mechanical refrigera-
tion systems were developed. These used refrigerants that
were toxic, such as sulfur dioxide and ammonia. Servicing
leaks from these systems was extremely dangerous for a
service technician.
The search for a safe, nontoxic refrigerant produced
chlorofl uorocarbons (CFCs). In 1930, the DuPont Company
produced Refrigerant Twelve. They called it R-12 and sold
it under the trade name “Freon-12.” Freon-12 was an excel-
lent refrigerant. It was nontoxic and had very good pressure
and temperature attributes. Once it became mass pro-
duced, it was also relatively inexpensive. From the 1930s
to the 1990s, variations of CFC refrigerants were developed,
and the service technician worked with three basic refriger-
ants: R-12, R-22, and R-502. The discovery of a hole in the
ozone layer, however, has dramatically increased the num-
ber of refrigerants used and the complexity of the service
technician’s job.
Introduction
to Refrigerants
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