Self Study Program 880173

R1234yf Refrigerant in Volkswagen VehiclesTablet Format

Volkswagen Group of America, LLC Volkswagen Academy Printed in U.S.A. Published 3/2017

©2017 Volkswagen Group of America, LLC.

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Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Refrigerant Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

R1234yf . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Table of Contents

1

Introduction

The Kyoto agreement, officially known as the Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC), is an international treaty negotiated in 1997 that sought to force industrialized countries to meet targets in reducing greenhouse gases.

In essence, the protocol established an obligation of “developed countries” to reduce the amount of greenhouse gas emissions. “Developing countries” such as China and India were exempted from compliance to the reduction targets and enforcement of penalties.

The basic content of the Kyoto protocol:

• By 2012, greenhouse gas emissions should be reduced by 5.2% from their 1990 level. While not a major component of greenhouse gas emission like agriculture and power production, the automobile refrigerant industry must also comply.

• By Nov 1, 2011 Refrigerant with GWP > 150 for newly-approved vehicles.

• By Jan 01, 2017 No new registrations for vehicles with R134a (for countries that signed and ratified Kyoto treaty)

Volkswagen is committed to environmental protection and abides by the terms of the Kyoto Protocol.

2

Introduction

Ozone Layer

The ozone layer in the stratosphere (15 to 35 km above the earth’s surface) reduces the UV radiation of sunlight. The natural concentration of the ozone in the stratosphere has been reduced in the past few decades, particularly by chlorofluorocarbons (CFCs), and this in turn has reduced the protection from UV radiation (hole in the ozone layer).

Besides the hole in the ozone layer, the problem of global warming is growing in importance. This “greenhouse effect” is defined as the accumulation of trace gases released by industry, commerce and intensive farming. These gases collect near the earth’s surface. Carbon dioxide (traffic) and methane (agriculture) play a major part in this, as do automotive refrigerants.

3

Refrigerant Types

Refrigerant TypesThere are many different types of refrigerant used by the automotove industry. The primary types are:

• R12

• R134a

• R1234yf

• R744 (CO2)

Each refrigerant has a different Global Warming Potential (GWP). The GWP is calculated in terms of the warming potential of one kilogram of a gas over a period (normally 100 years) relative to one kilogram of CO². A lower GWP refrigerant equals a higher emission credit for the manufacturers fleet.

The values are not absolutely measurable substance properties, but are determined using model calculations for the reactions taking place in the atmosphere. The actual numerical values will differ.

The GWP value represents only the refrigerant itself and does not provide any information about the manufacturing process or the energy requirements of the air conditioning system.

*All of the listed refrigerants with the exception of R-744 are considered to be Halogenated refrigerants, which means that they contain either chlorine, fluorine, bromine, or iodine.

R12: GWP 10,720

R1234yf: GWP 4

R134a: GWP 1,400

R744 (CO2): GWP 1

4

Refrigerant Types

Refrigerant R-12 (Dichlorodifluoromethane)

• Molecular Structure - CCl2F2

• GWP = 10,720

• Molar mass = 120.91 g/mol

• Contains chlorine, which depletes the ozone layer

• Remains in Earth’s atmosphere for over 100 years

• Last used by Volkswagen in MY 1993

• Often refered to by the name Freon

“Freon” is the registered brand name the refrigerants R-12, R-13B1, R-22, R-502, and R-503 manufactured by The Chemours Company

R-12 systems can still be repaired and recharged as long as R-12 remains available. However, it’s high cost and scarcity, along with the age of the vehicles using it, may make repairs uneconomical. Systems designed to use R-12 can be retrofitted to use R-134a as an air conditioning refrigerant.

5

Refrigerant Types

Refrigerant R-134a (Tetrafluoroethane)

• Molecular Structure CH2F-CF3

• GWP = 1,430

• Molar mass = 102.03 g/mol

• Does not contain chlorine

• Retained in Earth’s atmosphere for 13 years

• While not damaging to the ozone layer, it is a greenhouse gas

The standard for allowable refrigerant leakage has changed over the years. Originally, the SAE standard for R-12 systems was 8 oz. per year, which is why refrigerant systems had to be “topped up” at the beginning of the A/C season.

On R-134a systems, the standard is 0.5 oz. per year, which is less than 3% of the total system charge for most passenger vehicles. Therefore, they do not require a yearly refrigerant “top up.” If a vehicle with an R-134a refrigerant system requires a yearly service, it probably has a leak. After a few years, though, the system may lose enough refrigerant from allowable leakage to require recharging.

6

Refrigerant Types

Refrigerant R-1234yf (Tetrafluoropropene)

• Molecular Structure CF3CF=CH2

• GWP = 4

• Molar mass = 114 g/mol

• 1000 series organic refrigerant

• Retained in Earth’s atmosphere for 11 days.

• Mildly Flammable / Auto-ignition temp. = 761 °F

R-1234yf is a joint development of the Honeywell and DuPont chemical corporations. The refrigerant R-1234yf has a very low GWP because it has an atmospheric lifetime of only 11 days. R-1234yf reacts in the earth’s atmosphere as a result of natural decomposition processes.

R-1234yf was approved in in the United States early in 2011 under the EPA’s Significant New Alternatives Policy (SNAP) program for approving non-ozone depleting refrigerants. It is now legal to use subject to the EPA’s “Acceptable Subject to Use Conditions”. This means unique vehicle service ports, labeling etc. are required.

R-134a vehicles will not need to be converted to R1234yf systems and there are no plans to require retrofitting to the newer refrigerant. R-134a will remain available to service vehicles that still use. To discourage cross contamination, the price of R-134a may rise to meet R-1234yf.

7

Refrigerant Types

Refrigerant R-744 (Carbon Dioxide)

• Molecular Structure CO2

• GWP = 1

• Molar mass = 44.01 g/mol

• 700 series inorganic refrigerant

• Retained in Earths atmosphere for >200 years, yet is a naturally occurring gas.

• Exempt from section 608 of the Clean Air Act, meaning it can be legally vented to the atmosphere.

• Fun Fact: R744 in solid form is called dry ice.

Because CO² is a part of normal human and animal respiratory process, technically there is no need for recycling refrigerant; However, several complications are related to its use in automotive applications:

• The operating pressure can vary between 300-900 psi on the low side and up to 2000 psi on the high side. Due to the high pressures, cost of components substantially rise.

• The higher pressure generation will require additional mechanical force on the engine, which will in turn increase the GWP and CO² output of the vehicle itself.

• How is a leak in a refrigerant system in which the gas being used naturally occurs in the atmosphere located?

• If a leak were to develop into the passenger compartment, the CO² levels may become toxic to the passengers due to Carbon Dioxide being a powerful cerebral dilator.

• At concentrations of 2-10% nausea, dizziness, headache, mental confusion, increases blood pressure, and heavy breathing can occur.

• At concentrations above 10% suffocation and death can occur within minutes.

8

R1234yf

R134a vs . R1234yf

R134a and R1234yf have a very similar temperature to pressure curve.

Temperature in °C

Pres

sure

in B

ar

9

R1234yf

Identifying Features on the Vehicle

The following identifying features show that the air conditioning system is filled with the refrigerant R1234yf:

• Gray caps on the evacuating and charging valves

• Information label on the lock carrier

Caution

Refrigerant Filling Quantity for the Vehicle

Refrigerant Abbreviation

Rapid Evaporation May Cause Frostbite

Only Approved Refrigerant Oil Can Be Used

European Refrigerant StandardPart Number for this Vehicle Plate

Extremely Flammable

All work on the refrigerant circuit must be done by appropriately trained personnel

Gray Caps

10

R1234yf

VAS Air Conditioning Service Station

A new air conditioning service station (VAS 581 005) must be used for R1234yf refrigerant. The connections are mechanically coded to ensure that the R134a charging connectors on the air conditioning service stations cannot be connected to the R1234yf evacuating and charging valves. This will prevent mix-ups or accidental charging of the R1234yf system with R134a and vice versa.

A qualification certificate for work on air conditioning systems is required (identical to the R134a refrigerant air conditioning system). Please also comply with health and safety requirements and wear the following when performing work on the air conditioning system:

• Safety goggles

• Safety gloves

• Apron

VAS 581 005

Volkswagen Group of America2200 Ferdinand Porsche DriveHerndon, VA 20171April 2017