Modern Engineering Thermodynamics

548 CHAPTER 14: Vapor and Gas Refrigeration Cycles
HOW DID COMPRESSOR TECHNOLOGY DEVELOP?
By the end of the World War I (1914–1918), reciprocating piston compressors still dominated refrigerant technology, and
the primary refrigerants still in use in the Unoted States at that time were ammonia, carbon dioxide, and sulfur dioxide. In
1919, the French engineer Henri Corblin (1867–1947) patented a diaphragm refrigerant compressor in which the oscillating
motion of the center of a fixed diaphragm replaced the reciprocating motion of a piston in a cylinder. In 1918, the first
hermetically sealed refrigeration compressor was developed by the Australian Douglas Henry Stokes, in which the motor
and compressor were sealed together inside a container with the refrigerant. In 1933, Willis Carrier (1876–1950) developed
his first centrifugal refrigerant compressor for use with R-11.
During the last half of the 19th century, the development of refrigeration technology flourished in America,
especially in the South. In 1866, Thaddeus S. C. Lowe (1832–1913) developed a high-pressure (80 atm) carbon
dioxide compressor for manufacturing ice in Dallas, Texas, and Jackson, Mississippi; and in 1872, David Boyle
(1837–1891) developed an ammonia compressor (10 atm) for manufacturing ice in Jefferson, Texas. This
allowed CO 2 and NH 3 to enter the list of useful refrigerants.
The Swiss physicist Raoul Pierre Pictet (1846–1929) studied the various refrigerants then available and found that
sulfur dioxide had suitable thermodynamic properties. In 1874, he developed an SO 2 compressor and refrigerating
system that was quite successful. Sulfur dioxide has the advantages of being a natural lubricant for the compressor
and it does not burn. Its chief disadvantage is that, on contact with moisture, it forms corrosive sulfuric acid.
In the late 1920s, the American chemist and engineer, Thomas Midgley, Jr. (1889–1944), discovered that certain
fluorine compounds were remarkably nontoxic and odorless while simultaneously having the proper thermodynamic
properties of a good refrigerant. In the 1930s, the E. I. duPont de Nemours Company became commercially
involved in the refrigeration industry by manufacturing and selling Midgley’s discovery as a refrigerant.
DuPont marketed the product under the commercial trade name Freon.
Midgley’s refrigerants were halogenated hydrocarbons in which halogen atoms (mainly chlorine and fluorine)
were substituted for hydrogen atoms in simple hydrocarbon molecules. Midgley replaced the four hydrogen
atoms in methane, CH 4 , with two chlorine and two fluorine atoms to produce dichloro-difluoro-methane (or
dichlorodifluoromethane, CCl 2 F 2 ). Other common methane based refrigerants are monochlorodifluoromethane
CHClF 2 and trichloromonofluoromethane CCl 3 F. The complex chemical names of these compounds are logical
and technically correct, but they are difficult for the nonchemist to pronounce and remember. Consequently, a
confusing variety of commercial trade names, such as Freon, Genetron, Isotron, and Frigen, came into popular
use during the 1940s. Shortly thereafter, the American Society of Refrigerating Engineers (ASRE) 3 decided to
adopt a standard method of refrigerant designation that was based only on the use of numbers.
THE TEFLON CONNECTION!
A young DuPont chemist named Roy J. Plunkett discovered Teflon on April 6, 1938, while experimenting with a halogenated
ethylene gas for use as a refrigerant. On this day, Plunkett received a pressurized tank of tetrafluoroethylene (C 2 F 4 )
to study its properties as a nontoxic refrigerant. When he opened the tank nothing came out. After the valve was checked,
the tank was weighted and found to be the same weight as when it was full. Something made no sense, so Plunkett had
the tank cut open and found a waxy white powder. Being a chemist, Plunkett realized that the gas had somehow spontaneously
“polymerized” to form a new material, polytetrafluoroethylene. The waxy white powder had some remarkable physical
properties: it was not affected by strong acids or bases, was resistant to heat from −450°F to725°F (−270°C to 385°C),
and was very slippery. While these properties were interesting, it was decided that this new material had no particular commercial
value. Then came World War II and the top-secret atomic bomb project (the Manhattan Project). A material was
needed for gaskets that would resist the terribly corrosive properties of uranium hexafluoride gas. By a chance communication,
the director of the Manhattan Project became aware of the new polymeric material that Plunkett had discovered. It
was then made into a test gasket and found to be very successful at containing the corrosive gas. After World War II, the
new polymer material was not put to any practical use until it began to be used on nonstick cookware in France in 1954.
Nonstick cooking utensils were first sold in the United States on December 15, 1960, at Macy’s Department Store in New
York City. Taking letters from the complicated chemical name polytetrafluoroethylene, the new polymer was named Teflon.
3 The ASRE merged with the American Society of Heating and Air-Conditioning Engineers (ASHAE) to form the American Society of
Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) in 1959.