PRESENTED BY
G.K.R .SRIKANTH
A.MURALIDHAR

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HFO 1234 YF AS AN ALTERNATIVE REFRIGERANT FOR AUTOMOTIVE AIR CONDITIONING
ABSTRACT
HFO 1234 YF is a fluorinated hydrocarbon with the formula CH2=CFCF3. It has been replaced for R-134 as a refrigerant in Automobile Air Conditioner .HFO 1234 YF highly energy efficient, exhibits low toxicity, and can be potentially used in direct expansion automotive A/C systems with minimal design modifications . The Present Product was organized and going to be developed by DUPONT & HONEY WELL a Leading MNC group manufacturing HFO-1234yf is safe to use in automobiles as verified through extensive third-party testing, including crash testing conducted by automotive OEMs Many Automotive Companies had conducted experimental trails and decided to implement this Refrigerant for their up coming Products Unique attributes of HFO-1234yf and their significant environmental benefits are included in this Paper, in a proper Methodology
INTRODUCTION
Since the advent of the present Automotive Air Conditioning systems since 1940’s many things have undergone extensive changes improvements, such as Computerized Automatic Climate Control and added overall durability, have added complexity to today’s modern air conditioning system. To add the complications we now have tough environmental regulations that govern the very simplest of all tasks such as recharging the system with refrigerant R-12 commonly referred as Freon. Extensive scientific studies have proven that damaging effects of this refrigerant to our ozone layer and its manufacture has been banned by the US and many other countries planned to limit the production and not to use of known to deplete the ozone layers. which will allow it to use the new industry accepted environmental friendly refrigerant HFO-1234yf
BASIC AUTOMOTIVE AIR CONDITIONING PARTS
1.COMPRESSOR
2.CONDENSER
3.EVAPORATOR
4.PRESSURE REGULATING DEVICES
5.ORIFICE TUBE
6.THERMAL EXPANSION VALVE
7.RECEIVER-DRIER
8.ACCUMULATOR
ABOUT HFO 1234yf
HFO1234YF
Developed for mobile air conditioning in vehicles
Global usage
Environmentally friendly Comprehensively tested
Reliable
Cost-efficient
HFO - (Describes an organic fluorine compound called
Hydrofluoro Olefin)
1234 Stands for a specific compound: 1 = double bond 2 = hydrogen's 3 = carbons 4 = fluorine's
Yf Denominates the specific isomer (position of the fluoro atoms)
GLOBAL WARMING POTENTIAL
The next generation refrigerant must be safe, effective, and efficient.Under the EU mobile air conditioning (MAC) directive, new vehicle types introduced in the EU on or after January 1, 2011, must use Refrigerants with a global warming potential below 150The transition will be complete by 2017. Honeywell and DuPont – two leaders in refrigerant technology – agreed in 2007 to jointly develop a new refrigerant to meet the new EU regulations for automotive air conditioning
The GWP (Global Warming Potential) indicates how much a material  can contribute to global warming compared to CO2.HFO-1234yf has an ultra low global warming effect. The GWP is 4 - significantly below the EU threshold of 150.
Global warming potential (GWP) is a measure of how much a given mass of greenhouse gas is estimated to contribute to global warming. It is a relative scale which compares the gas in question to that of the same mass of carbon dioxide (whose GWP is by definition 1).
GWPs are calculated as the ratio of the radiative forcing that would result from the emissions of one kilogram of a greenhouse gas to that from emission of one kilogram of carbon dioxide over a period of time (usually 100 years).
 HFO-1234YF MEETS THE CHALLENGE:
Hydrofluoroolefin (HFO) 1234yf was the result of a multi-year R&D program and has undergone extensive testing since August 2007. In comprehensive toxicity testing, it was found to be acceptable for use. (GWP) of 4 is well below the EC regulations of 150.HFO-1234yf has an atmospheric lifetime of only 11days A global solution, HFO-1234yf is able to provide efficient and effective cooling in even the hottest regions. As a near drop-in replacement for the current refrigerant R-134a, it allows fast and easy adoption for automakers. Its Global Warming Potential days -- compared to 13 years for R-134a and more than 500 years for carbon dioxide
COMFORT AND WELL BEING:
Based on these tests, many leading OEMs believe HFO-1234yf is safe to use in mobile air conditioning. As part of the development of HFO-1234yf, independent third-party groups such as the Society of Automotive Engineers and the Japanese Independent, global testing laboratories such as WIL Labs and TNO Laboratories in the Netherlands have conducted comprehensive toxicity tests on HFO-1234yf. Based upon the results of these tests, Honeywell and DuPont have concluded that HFO-1234yf is safe for use in mobile air conditioning
These reports have been reviewed and accepted by the Belgium Competent Authority as well as toxicologists from several industry groups. Many materials used every day – including CO2 – can be toxic if exposures are too great. One government study called for risk mitigation devices to be installed in cars using CO2-based A/C systems to avoid health effects ranging from dizziness to loss of consciousness if CO2 concentrations become too high. Tests conducted by OEMs have concluded that the use of HFO-1234yf in mobile air conditioning will not result in high exposure levels for automobile drivers and passengers
FLAMMABILITY CHARACTERISTICS:
HFO-1234yf is not flammable, while the minimum ignition energy lies between5, 000 and 10,000 mJ for HFO-1234yf. In other words, the flammability risk associated with the use of HFO-1234yf both inside the passenger cabin and in the engine compartment is assessed under what the industry considers worst case leak scenarios
Gasoline ignites at 0.2 mJ.
Spark plugs need a minimum energy of approximately 40 mJ to ignite fuel.
Auto ignition temperature of air/refrigerant mixture: 405 degrees Celsius.
THERMOPHYSICAL PROPERTIES OF HFO-1234yf
GM TO PREFER HFO-1234YF
General Motors Co. will launch HFO-1234yf as an air-conditioning refrigerant in 2013 Chevrolet, Buick, GMC and Cadillac models in the US. This could be the first passenger vehicle application of the new refrigerant in the US, which has 99.7% lower global warming potential (GWP) than the current refrigerant.HFO-1234yf, supplied by Honeywell, breaks down faster in the atmosphere than the refrigerant currently used (R-134a)
INTERESTING FACTS ABOUT HFO-1234YF
HFO-1234yf has the lowest Life-Cycle Climate Performance compared to CO2
CO2 air conditioning systems have higher indirect greenhouse gas emissions than HFO-1234yf systems because they are less efficient
Unlike HFCs and CFCs which take generations to decompose, HFO-1234yf does not accumulate in the atmosphere creating long-term problems
Due to the extremely high pressure and harmful health effects of CO2, the air conditioning system must be carefully designed to minimize the risk to passengers and service people.
Society of Automotive Engineers and automakers using real-world conditions, have demonstrated that 1234yf is safe to use in mobile air conditioning
CONCLUSION
Environmentally friendly,
Easier maintenance (similar to R134a)
Economically better (faster expansion)
Better efficiency on warmer climate condition, where AC is a mandatory equipment,
1234yf application is mandatory for acceptable “time to market” for Electric and Hybrid vehicles