THERMODYNAMIC PROPERTIES OF FREON 12 REFRIGERANT (R-12).

As first my POST here at Under the Ice (http://freon12museum.blogspot.com/):


Thermodynamic Properties of Freon® 12 Refrigerant (R-12)

SI Units.

Dichlorodifluoromethane is an inert gas that has a long history acting as a refrigerant, allowing us to stay cool in the summer, and as a spray propellant for important consumer substances.  Dichlorodifluoromethane owes many of its desirable properties to its C-F bonds and synthesis involves organofluorine chemistry.  

Synonyms: dichlorodifluoromethane; algofrene type 2; arcton 12; arton 6; carbon dichloride difluoride; CF 12; CF 12(halocarbon) CFC 12; CFC-12; chladone 12; dichlorodifluoromethane (CCL2F2); dichlorodifluoromtheane (DOT French); dichlorodifluoromethane (DOT); diclorodifluorometano (DOT Spanish); difluorodichloromethane; dymel 12; electro-CF 12; eskimon 12; F 12; F 12 (halocarbon); F-12; FC 12; FCC 12; FWK 12; fluorocarbon 12; forane 12; freon 12; freon F-12; freon ® 12; frigen 12; frigen R12; fron 12; gas refrigerante R-12 (DOT Spanish); gaz refrigerant R-12 (DOT French); genetron 12; genetron ® 12; halon 122; halon ® 122; HC 12; isceon 122; isotron 12; khladon 12; ledon 12; methane, dichlorodifluoro-; propellant 12; R 12; R 12 (refrigerant); refrigerant 12; refrigerant gas R-12; refrigerant R 12; SDD 100; and ucon 12.

Regulatory Name: CFC-12, Dichlorodifluoromethane

Formula: CC12F2

DOT Label: Non-flammable Gas

CAS: 75-71-8

STCC: 4904516, 4904561

CHRIS: DCF

UN Number: 1028

Structure: (Black = Carbon, Yellow = Fluorine, Green = Chlorine)

Physical Properties: Colorless gas with a characteristic ether-like odor at >20% by volume.

MW: 120.914 g/mol
BP: -29.8°C
VP: 5.7 atm
MP: -158°C

Tables of  the  thermodynamic properties of R-12 have been developed and are presented here.
This information is based on values calculated using the NIST REFPROP Database (McLinden, M.O., Klein,
S.A., Lemmon, E.W., and Peskin,A.P., NIST Standard Reference Database 23, NIST thermodynamic
and transport properties of refrigerants and refrigerant mixtures – REFPROP version 6.01,
Standard Reference Data Program, National Institute of Standards and
Technology, 1998). 

Units
P = Pressure in kPa. Absolute
T = Temperature in Celcius
Vf = Fluid (liquid) specific volume in cubic meters per kilogram
Vg = Vapour (gas) specific volume in cubic meters per kilogram
df and dg = Fluid and Vapour (respectively) densities in kilograms per cubic meter 

H = Enthalpy (kJ/kg)
S = Entropy (kJ/kg.K)
Physical Properties Chemical Formula CCl2F2
Molecular mass 120.91
Boiling Point -29.75°C At one atmosphere
Critical Temperature 111.97°C
Critical Pressure 4136 kPa
Critical Density 565.0 kg/m3
Critical Volume 0.0018 m3/kg

In 1987, the Montreal Protocol, an international environmental agreement to reduce and phase out
chlorofluorocarbons (CFCs), catapulted the world’s refrigerator makers from a slow life that for many
decades had seen no major product innovation into one where they would be forced to either innovate
within an extremely short time period and engage in major technical development or else quit their
industry.
CFCs were believed to be major depleters of the ozone layer in the stratosphere, causing increased skin
cancer and global warming. Since refrigerators depended on them as coolants and as blowing agents used
in the production of foam insulation, the stipulations of the Montreal Protocol, which initially required
a CFC ban by the year 2000, then by 1995, were a massive threat to the refrigerator industry.
The Montreal Protocol was not a law by itself, it merely required its signatory countries to enact
legislation requiring the phaseout of CFCs and other ozone-depleting substances at the latest by the date
it stipulated. In most cases the regulation that was subsequently enacted by the individual countries
followed the deadline recommended in the protocol. Germany was the only nation to require an earlier
phaseout date, forcing its refrigerator industry to search and find even faster a safe substitute for CFCs,
but providing it at the same time with an opportunity to gain a first mover advantage over foreign
competing nations.Any CFC substitute that was researched had to be not only in compliance with the stipulations set forth
by the Montreal Protocol, but also be at least as energy efficient, be safe to the user, and be as
economical as possible. Energy efficiency was particularly important, because many countries either had
energy efficiency laws (as was the case in the U.S.) or very demanding customers (as was the case in
Germany) which provided pressure to offer only energy efficient appliances. Safety was also an important
concern.
Many countries, including the U.S. and European countries, had laws regulating appliance
safety.
 By the early 1990s it had become evident that there were two major technological avenues that could be
followed to comply with the Montreal Protocol.One involved the use of hydrofluorocarbons (HFCs) as
coolants and hydrochlorofluorocarbons (HCFCs) as blowing agents for insulating foams. HFCS were in
compliance with the Montreal Protocol and thought to be safe to the refrigerator’s user. However, they
were slightly less energy efficient - a disadvantage that could be offset by small changes to the
refrigerators design. They were also more expensive than CFCs, causing in Germany an average increase
in refrigerator prices by some 5 % to 8 % . Their major drawback was that, while not dangerous to the
earth’s ozone layer. they were a powerful greenhouse gas that was thought to contribute to global
warming and climate change. There was no regulation on HFCs, but the slight risk that they might be
regulated Sometime in the future meant that refrigerator makers which focused on HFCs risked focusing
on a transitory solution.
 HCFCS were an even riskier substitute - from an environmental as well as from a competitive point of
view. Refrigerator insulation foams blown with HCFCs were economical, provided sufficient energy
efficiency and posed no safety risk. However, HCFCs contributed to global warming and posed a risk
to the ozone layer. For this reason, the Montreal Protocol required their phaseout by the year 2020.
Thus, manufacturers developing HCFC-based insulation foams followed a dead end; they could be sure
to be forced once again to convert their production to a new technology in the foreseeable future.
The Refrigerator Industry
By the early 1990s it had become evident that there were two major technological avenues that could be
followed to comply with the Montreal Protocol.One involved the use of hydrofluorocarbons (HFCs) as
coolants and hydrochlorofluorocarbons (HCFCs) as blowing agents for insulating foams. HFCS were in
compliance with the Montreal Protocol and thought to be safe to the refrigerator’s user. However, they
were slightly less energy efficient - a disadvantage that could be offset by small changes to the
refrigerators design. They were also more expensive than CFCs, causing in Germany an average increase
in refrigerator prices by some 5 % to 8 % . Their major drawback was that, while not dangerous to the
earth’s ozone layer. they were a powerful greenhouse gas that was thought to contribute to global
warming and climate change. There was no regulation on HFCs, but the slight risk that they might be
regulated Sometime in the future meant that refrigerator makers which focused on HFCs risked focusing
on a transitory solution.
The other major technological route to follow besides employing HFCs and HCFCs involved the use of
hydrocarbons. Hydrocarbons, such as propanes, butanes, isobutanes. or pentanes, could be used both
as refrigerants and as blowing agents for polystyrene insulating foams. They were environmentally
benign, could easily be obtained all over the world, and were very cheap. Theoretically hydrocarbons
provided better energy efficiency than HFCs and HCFCs, although practically hydrocarbon-blown
insulations were slightly less efficient, requiring somewhat thicker insulations. Hydrocarbons were
explosive and thus represented a certain safety risk during refrigerator production as well as during
refrigerator usage, but this risk could be minimized to acceptable levels by introducing suitable safety
equipment. Like HFC- and HCFC-based systems, refrigerators employing hydrocarbons cost some 5%
to 8% more than CFC-based refrigerators. Unlike HFC- and HCFC-based systems, they did not pose
 any environmental risks and thus were certain never to be banned for environmental reasons, rendering
research efforts and production equipment obsolete.
By early 1994, most refrigerator makers in the world were focusing on the HFC/HCFC alternative with
all its environmental risks. The only exception was Germany, where, after a sometimes agonizing
struggle to decide which technological route to choose, most refrigerator makers had decided to adopt
the hydrocarbon route which did not pose any environmental risks and with further research and
experience was likely to be as cost-efficient as the HFC/HCFC route. How was it possible that the
German refrigerator industry, a highly competitive industry representing 11.1% of the world’s
refrigerator production and 13.4% of the world’s exports of refrigerators, had chosen a technological
route that was difficult from that chosen by the rest of the world?
There were several reasons, among them stricter and earlier regulation, which had sensitized producers
and consumers to the issue -- a very demanding and environmentally conscious home market -- as well
as a chance event in the form of a pressure campaign by an environmental group that had hit precisely
at the right time and at the right place.
The first hydrogen-based refrigerator had been built in Germany by the small East German manufacturer
Foron after the environmental pressure group Greenpeace had acquainted it with the technology and
awarded it a small $15,000 development contract. Greenpeace also conducted a publicity campaign that
prompted a large number of environmentally conscious Germans to place orders for the newly developed
refrigerator. The extraordinary success of the campaign convinced not only Foron that the hydrocarbon-
technology had real market potential, but also its West German competitors, who had initially developed
HFC/HCFC-based refrigerators.
Subsequently, one competitor after another announced similar
hydrocarbon-based refrigerators.