AC Refrigerants.


Which refrigerant is used in air conditioner?

CHLOROFLUOROCARBONS(CFCs)

R-11 Trichlorofluoromethane   CCI3F

R12   Dichlorodifluoromethane  CCI2F2

R-113 Triclorotrifluoroethane   CCI2FCCIF2

R-114  Diclorotetrafluoroethane CCIF2CCIF2

R-115    Chloropentafluoroethane CCIF2CF3

HYDROCHLOROFLUOROCARBONS(HCFCs)

R-22 Cholordifluoromethane CHCIF2

R-123 Dichlorotrifluoroethane CHCI2CF3

R-124 Chlorotetrafluoroethane CHCIFCF3

R-142b Chlorodifluoroethane    CH3CCIF2

   HYDROFLUOROCARBONS(HFCs)

R-125 Pentafluoroethane  CHF2CF3

R-134a Tetrafluoroethane CH2FCF3

R-23     Trifluoromethane   CHF3

R-32      Difluoromethane   CH2F2

R-125    Pentafluoroethane CHF2CF3

R-143a  Trifluoroethane      CH3CF3

R-152a   Difluoroethane     CH3CHF2

R-410     Blend                    CH2F2/CHF2CF3

Some hydrocarbon (HC) refrigerants are:

Propane

Butane

Isobutane

Isopentane

Methane

Ethane

R-441A (HC blend of ether,propane,isobutene,and n-butane.


Which refrigerant is used in auto air conditioner?

R-744(CO2)

R-744 systems are in development and are expected to enter the original equipment market in the near future.CO2 systems are more fuel-efficient and can increase cooling performance as compared to R-134a systems.CO2 systems operate at 7 to 10 times the pressure of systems,containing R-134a.Due to the very high pressures associated with R-744 EPA has established conditions of use.

Conditional use of R-744(CO2)

Engineering strategies or devices shall be incorporated into the system such that foreseeable leaks into the passenger compartment do not result in concentrations greater than the CO2 short-term exposure limit (STEL) of 3% for 15 minutes.Manufactures must adhere to all the safety requirements listed in the Society of Automotive Engineers(SAE)Standard J639,including unique fittings and a high pressure system warning label.

R-152a

R-152a is an HFC compound.It operates with similar characteristics to R-134a but possesses a much lower GWP(120 to 140) versus 1300GWP for R134A.R-152a systems utilize from 7% to 22% less energy to produce the same cooling.Due to flammability concerns EPA has established conditions of use for R-152a.

Conditional Use of HFC-152a

Engineering strategies or devices shall be incorporated into the system such that foreseeable leaks into the passenger compartment do not result in HFC-152a concentrations of 3.7% or above in any part of the free space inside the passenger compartment for more than 15 seconds.Manufactures must adhere to all the safety requirements listed in the Society of Automotive Engineers(SAE)Standard J639,including unique fittings and a flammable refrigerant warning label.

HFO-1234yf

The Hydro Fluoro Olefin Refrigerant HFO-1234yf was developed through a joint project between DuPont and Honeywell.HFO-1234yf is expected to become the preferred global alternative refrigerant candidate for automotive OEM  applications and the aftermarket.HFO-1234yf has a GWP of 4 and an ODP of zero.HFO-1234yf cooling’s capacity is comparable to HFC-134a and is compatible with HFC-134a components.


What refrigerant is used today?

Most refrigerants are made from two molecules,methane and ethane.These two molecules contain hydrogen (H) and carbon (C) and are referred to as pure hydrocarbons (HCs).

Pure hydrocarbons were at one time considered  good refrigerants,but because of their flammability they were not used after the 1930s to any larger degree.However,hydrocarbons are making a comeback in Europe,where they are used in domestic refrigerators,and are also making a comeback in the United States as a small percentage of the mixture in refrigerant blends for nonflammable applications.

Abbreviations are used to describe refrigerants chemically and to make it simpler for technicians to differenciate between them.The following are some common abbreviations:

Chlorofluorocarbons(CFCs)

Hydrochlorofluorocarbons(HCFCs)

Hydrofluorocarbons(HFCs)

Hydrocarbons(HCs)

Hydrofluoro-olefins(HFOs)

The CFCs contain chlorine,fluorine,and carbon and  are considered the most damaging because their molecules are not destroyed before they reach the stratosphere.All refrigerant in the CFC group ere phased out at the end of 1995.As of july 1/1992,it is illegal to intentionally vent CFC refrigerants into the atmosphere.

CHLOROFLUOROCARBONS(CFCs)

R-11 Trichlorofluoromethane   CCI3F

R12   Dichlorodifluoromethane  CCI2F2

R-113 Triclorotrifluoroethane   CCI2FCCIF2

R-114  Diclorotetrafluoroethane CCIF2CCIF2

R-15    Chloropentafluoroethane

The HCFCs contain,hydrogen,chlorine,fluorine and carbon.The amount of chlorine is small,but they also have hydrogen,which makes them less stable in the atmosphere.HCFCs group is scheduled for a total phaseout by the year 2030.As of july 1,1992,it became illegal to intentionally vent HCFC refrigerants into the atmosphere.

HYDROCHLOROFLUOROCARBONS(HCFCs)

R-22 Cholordifluoromethane CHCIF2

R-123 Dichlorotrifluoroethane CHCI2CF3

R-124 Chlorotetrafluoroethane CHCIFCF3

R-142b Chlorodifluoroethane    CH3CCIF2

The HFCs contain hydrogen,fluorine,and carbon atoms.HFC’s molecule contain no chlorine atoms and will not deplete the earth’s protective ozone layer,but they do have a small potential for contributing to global warming.

           HYDROFLUOROCARBONS(HFCs)

R-125 Pentafluoroethane  CHF2CF3

R-134a Tetrafluoroethane CH2FCF3

R-23     Trifluoromethane   CHF3

R-32      Difluoromethane   CH2F2

R-125    Pentafluoroethane CHF2CF3

R-143a  Trifluoroethane      CH3CF3

R-152a   Difluoroethane     CH3CHF2

R-410     Blend                    CH2F2/CHF2CF3

The Hydrofluoro-olefin (HFO) refrigerants are referred to as fourth generation refrigerants for the 21st century.HFOs are distinguished from HFCs by being derivatives of olefins rather than alkanes(paraffins).

Two popular HFO refrigerants are HFO-1234-yf and HFO-1234ze.Both HFO-1234yf and HFO-1234ze have a zero Ozone Depletion Potential with extremely low Global Warming Potentials(GWP).Because of their lower GWP values,these refrigerants have a much shorter lifecycle in the atmosphere.These two HFO refrigerants have an A2L safety classification,meaning they have low toxicity but are slightly flammable.

HFO-1234yf is a low GWP replacement for R-134a intended for use in mobile air conditioning systems in the automotive industry.HFO-1234ze is intended to replace R-410a in residential and light commercial air conditioning.

HYDROCARBON (HC) REFRIGERANTS.

The fourth group of refrigerants is the hydrocarbon (HC) group.HC refrigerants are classified by ASHRAE in the A3  safety group.Refrigerants in the A3 safety group are highly flammable.

Pure HC refrigerants have no chlorine or fluorine in their molecules;they contain nothing but hydrogen and carbon,thus they have a zero (ODP)

HC refrigerants do contribute to global warming,but their global warming potencial (GWP) is very low when compared to CFC,HCFC and HFC refrigerants.

HC refrigerants have better energy efficiencies and reduced energy usage when compared to currently used HFC refrigerants.Hydrocarbons refrigerants are created by nature,not a chemical company,and are often referred to as natural refrigerants.The most efficient and environmentally safe refrigerants that exist in the world today are all natural refrigerants.These refrigerants include hydrocarbons,ammonia,air,water,and carbon dioxide.

In the USA, only some HC refrigerants have been approved by the EPA under its Significant New Alternative Policy(SNAP).SNAP has approved HC refrigerant use in the USA only in new equipment,in limited conditions,and with limited refrigerant charge amounts because of their high flammability.

Some hydrocarbon (HC) refrigerants are:

Propane

Butane

Isobutane

Isopentane

Methane

Ethane

R-441A (HC blend of ether,propane,isobutene,and n-butane.


Is a Freon leak dangerous?

The greatest effect is in the stratosphere.The stratosphere is the earth’s security blanket.It is located between 10 and 30 miles above sea level and is comprised of, among other things,Ozone.Ozone protects us from harmful ultraviolet radiation and helps maintain stable Earth temperatures.Stratospheric Ozone  depletion is a global problem.

The chlorine in these compounds is the culprit.When a chlorine atom meets with an Ozone molecule,it takes on Oxygen atom from Ozone.This forms a compound called Chlorine Monoxide (CIO) and leaves and O2 molecule.The Chlorine Monoxide  will collide with another Ozone molecule,release its Oxygen atom,forming two O2 molecules,and leave the chlorine free to attack another Ozone molecule.A single Chlorine atom can destroy 100,000 Ozone molecules.

Depletion of Ozone in the stratosphere causes:

CROP LOSS

INCREASE IN EYE DISEASES

SKIN CANCER

REDUCED MARINE LIFE

DEFORESTATION

INCREASED GROUND LEVEL OZONE.

Is CFC harmful to humans?

The impact that refrigerants such as HFC134a has on global warming potencial is 1,340 times that of the carbon dioxide.The GWP of Carbon Dioxide (CO2) is used as the baseline against which all other gases are measured(CO2=1.0 GWP-HFC134a=1,340 GWP).In other words,releasing 1 pound of R134a is equal to emitting into our atmosphere 1,340 pounds of CO2.

In large quantities, refrigerants can cause suffocation because they are heavier than air and displace oxygen.Inhaling refrigerant vapors or mist may cause heart irregularities,unconsciousness,and oxygen deprivation leading to death(asphyxia).

At high temperatures, R-12 and R-22 decompose to form Hydrochloric acid, Hydrofluoric acid, and Phosgene gas.

Refrigerants CFC-12, CFC-11, and HFC-134 are categorized as A-1(Low flammability ,low toxicity).


How much does it cost to repair a refrigerant leak?

Some common areas and causes for active leaks are: corrosion or porosity on ac lines or hoses. Evaporator core corrosion or condenser, o-rings incorrect size or missing after service of ac components. Damaged service port valve cores after evacuating and recharging the ac system. Improperly torqued component can cause active leaks too.

The price range for repairing a leak will depend on the make model and year of the vehicle and the time to replace or fix the damaged component plus the price of the component itself. Price range could vary between $200.00 – $2000.00.


How do you tell if your AC has a Freon leak?

All sealed systems leak.The leak could be 1 pound per second or as low as 1 oz every 10 years.Every pressurized system leaks because “flaws” exist at every joint fitting,seal or weld.These flaws may be too small to detect with even the best of leak detection equipment.But given time,vibration,temperature,and environmental stress,these  flaws become larger,detectable leaks.

It is technically incorrect to state that a unit has no leaks.All equipment has leaks to some degree.A sealed system which has operated for 20 years without ever needing a charge is called a “tight system”.The equipment still has leaks,but not enough leakage to read on a gauge or affect cooling performance.No pressurized machine is perfect.

Gas escapes at different times and at different rates.In fact,some leaks cannot be detected at the time of the leak test. Leaks my plug and then reopen under peculiar conditions.A leak is physical path or hole,usually of irregular dimensions.The leak may be the tail end of a fracture,a speck of dirt on a gasket,or a microgroove between fittings.

Oil spotting is the first quick check but is not always reliable,for the following reasons:

1-Oil is always present at Schrader valves and access ports due to the discharging of refrigerant hoses on the manifold and gauge set.Often these parts are falsely identified as the main point of leakage.

2-Oil blotches can originate from motors,pumps, and other sources.

3-Oil residue may be the result of a previous leak already serviced.

4-Oil is not always present at every leak site.It may take months, even years , of unit operation to cause enough oil blow-off to accumulate on the outer side.

5-Oil may not be present with microleaks.

6-Oil may not reach certain leak positions.

7-Oil may not be present on new start-ups.

The ac compressor cycling too often on some systems could be a sign of the  auto air conditioner low refrigerant charge.If your ac is not cooling as usual it may be leaking refrigerant.

An electron micrograph of a “clean” silver soldered joint,shows crack lines and other impurities of the metal.Futher magnification shows actual metal separation.

Can a Freon leak make you sick?

In the event of a LARGE release of refrigerant in a confined area,Self Contained Breathing Apparatus(SCBA) is required.If a large leak of refrigerant occurs in an enclosed area,and SCBA is not available,IMMEDIATELY VACATE AND VENTILATE the area. Inhaling refrigerant vapors can cause heart irregularities,unconsciousness,and oxygen deprivation leading to death.

If your ac is not cooling as usual it may be leaking refrigerant. Auto A/C Repair LLC offers free estimates over the phone or on site. Call today at (786) 483-9406