Handbook of air conditioning and refrigeration / Shan K

● Halide torch. This method is simple and fast. When air flows over a copper element heated by a
methyl alcohol flame, the vapor of halogenated refrigerant decomposes and changes the color of
the flame (green for a small leak, bluish with a reddish top for a large leak).
● Electronic detector. This type of detector reveals a variation of electric current due to ionization
of decomposed refrigerant between two oppositely charged electrodes. It is sensitive, but cannot
be used where the ambient air contains explosive or flammable vapors.
● Bubble method. A solution of soup or detergent is brushed over the seals and joints where leakage
is suspected, producing bubbles that can be easily detected.
9.4 PHASEOUT OF OZONE DEPLETION REFRIGERANTS
Refrigerant Use
The use of CFCs and HCFCs is a global concern. Approximately two-thirds of all fully halogenated
CFCs were used outside the United States in the mid-1980s. In 1985, the total use of halocarbons
in the United States was 611 million lb (0.28 million ton). These halocarbons were used in foam insulation,
automotive air conditioners, new systems of Air Conditioning and Refrigeration Institute
(ARI) members, and other products. Foam insulation blown by CFCs was the largest user. Automotive
air conditioners made up 19 percent of the total and CFCs purchased by ARI members for new
systems made up 5 percent of the total use. Of the CFCs and HCFCs purchased by ARI members,
HCFC-22 made up 77 percent, while CFC-11 and CFC-12 each made up about 10 percent.
Ozone Depletion and Global Warming Potentials
REFRIGERANTS, REFRIGERATION CYCLES, AND REFRIGERATION SYSTEMS 9.7
To compare the relative ozone depletion caused by various refrigerants, an index called the ozone
depletion potential (ODP) has been proposed. ODP is the ratio of the rate of ozone depletion of 1 lb
of any halocarbon to that of 1 pound of CFC-11. The ODP of CFC-11 is assigned a value of 1. The
following are the ODP values for various refrigerants:
Refrigerant Chemical formula ODP value
CFC-11
CFC-12
CFC-13B1
CFC-113
CFC-114
CFC-115
CFC/HFC-500
CCl3F CCl2F2 CBrF3 CCl2FCClF2 CClF2CClF2 CClF2CF3 CFC-12 (73.8%)/HFC-152a (26.2%)
1.0
1.0
10
0.8
1.0
0.6
0.74
CFC/HCFC-502 HCFC-22 (48.8%)/CFC-115 (51.2%) 0.33
HCFC-22
HCFC-123
HCFC-124
HCFC-142b
HFC-125
HFC-134a
HFC-152a
CHClF2 CHCl2CF3 CHClFCF3 CH3CClF2 CHF2CF3 CF3CH2F CH3CHF2 0.05
0.02
0.02
0.06
0
0
0
Similar to the ODP, the halocarbon global warming potential (HGWP) is the ratio of calculated
warming for each unit mass of gas emitted to the calculated warming for a unit mass of reference
gas CFC-11. The HGWPs of various refrigerants are listed in Table 9.1. In addition to the HGWP,
another global warming index uses CO 2 as a reference gas. For example, 1 lb of HCFC-22 has the