From: ghg@freedom.ecn.purdue.edu (George Goble)
Newsgroups: rec.autos.tech,talk.environment
Subject: Re: A/C converson from Freon to R134- Necessary?
Date: 30 Oct 1994 13:03:08 GMT
Organization: Purdue University Engineering Computer Network
Lines: 53

In article <B.Hamilton.80.2EB327B5@irl.cri.nz> B.Hamilton@irl.cri.nz
(Bruce Hamilton) writes:

>appears. Approximately 90% of new vehicle AC systems are 
>now HFC134a, and no alternatives are compellingly superior
>in all the necessary requirements, although it is possible
>new systems auto A/C sytems may move to flammable HC
>mixtures - with the requirement that leak rates are reduced.
>It is very likely that most retrofit systems will be HFC-134a 
>until the vehicle is eventually scrapped.

An HFC-134a retrofit may cause the vehicle to be scrapped early.
Existing chlorides which cannot be flushed out cause the PAG
oil to fail and wreck the system.  If the system was ever flushed
with R-11 (considered good practice before the ozone mess), the 134a Oil
oil may last only a few weeks before failure.  

Polyol Ester (POE) oils are more tolerant of residual chlorides than
PAG oils, but Esters are VERY moisture sensitive, they have to be
shipped in metal cans..and can easily break down into fatty acids
and alcohols (formation products) under some conditions.  Bare
steel and heat are two catalysts for decompostion.  A number of
"passivators" are being tried and vary from oil to oil to try
to combat this.

Even some stationary equipment mfgrs are reporting problems with NEW
R-134a equipment (refrigerators, etc).  Some equipment has been
recalled.  We have even heard of a company suspending production
on new refrigerators until R-134a/oil problems can be worked out.

Under the hood, radiator temps often hit 220F or so.. Since the
condenser is bolted next to the radiator, it sometimes sees these
temps also (I have measured condenser temps on an an instrumented
vehicle).  The "critical" temp of a gas, is the temp at above which
it will not condense to a liquid, no matter what the pressure..

You have heard about all the low-capacity (poor cooling), hoses/
compressors busting (hi pressures) of R-134a?  R-134a has
a steeper pressure/temp curve than does R-12.  R-134a has a
critical temp of 214F vs 234F of R-12.  Portions of the condenser
may easily hit 214F, at which point the R-134a will not liquify
at all or very little ... leading to poor performance in
stopped traffic/low air flow periods.

R-134a needs a much larger condenser due to this, and it located
away from the radiator (may not be possible), and beefed up
radiator fans to suck in more cool air than for R-12.  Retrofitted
R-12 systems are not likely to have large condensers/more air 
flow.. so they will have very poor low speed/stopped performance.

Zeotropic blends (R-400 series refrigerants) can extend the
active phase change area of the condenser, thereby increasing
performance of the system provided operating conditions are met.

--ghg

From: ghg@freedom.ecn.purdue.edu (George Goble)
Newsgroups: rec.autos.tech
Subject: Re: A/C converson from Freon to R134- Necessary?
Message-ID: <3968vj$4cu@mozo.cc.purdue.edu>
Date: 1 Nov 1994 20:38:11 GMT
Organization: Purdue University Engineering Computer Network
Lines: 201

In article <B.Hamilton.82.2EB4CD46@irl.cri.nz> you write:

>In article <3905ic$55p@mozo.cc.purdue.edu> ghg@freedom.ecn.purdue.edu
>(George Goble) writes:
>
>>In article <B.Hamilton.80.2EB327B5@irl.cri.nz> B.Hamilton@irl.cri.nz
>>(Bruce Hamilton) writes:
>.....
>>>It is very likely that most retrofit systems will be HFC-134a 
>>>until the vehicle is eventually scrapped.
>
>>an HFC-134a retrofit may cause the vehicle to be scrapped early.
>
>Any shonky ( =dubious quality ) retrofit adversely affects operational
>life - not just HFC-134a retrofits. That's why Ford has been very 
>careful. From Car & Driver? July 1994. "The Last, fretful Days of R-12"

If FORD had given a damn about A/C systems at all, they would have
never introduced the "spring-lock" connections in their A/C systems.
Those have been nothing but trouble  for years... go ask any independent
service shop about those designed to be leaky connectors. While you are
at it, ask the service shop for a list of their failure-prone compressor
model numbers.  Any why does the service shop's cost for a FORD drier
come to around $120 (plain 'ole XH5 R-12 drier).. The shop has to mark
it up again.  GM, Chysler, and independent driers are often $15-$25
shop cost.  Sounds like Ford just cares about maximizing serivice
income.

[... deleted ..]

Fact of life:

Many major publications RELY on heavy advertising from the auto industry.
Like Millions of $$$ in advertising.

One cannot cut off the hand which feeds them.

These publications CANNOT print things which tick off the auto
industry (i.e. good things about blends, bad things about R-134a, etc)..
If they did that, all the big three + Japan would yank ALL their
adds.. for many months, causing the publication economic ruin.

I know of several instances where popular publications have "prepared"
stories/interviews/photo sessions, for alternative refrigerants, etc,
and have scuttled them when the advertising dept found out.

One mag called one model of some Japanese car a "lemon" once, and
lost over a year's worth of advertising from that one company.

>Still, confusion will most likely reign, because customers will look for cheap
>solutions, and some repairmen will promise anything. There'll be short-cut
>kits and magic potions. An example is a refrigerant that's a mixture of 
>propane and butane. "You don't have to change anything!" It'll cool.
>Lubrication is iffy. And if a leak gets sparked in the engine bay, Kaboom!"

Lubrication is VERY GOOD for hydrocarbons in mineral oil.  There is an
upcoming EPA approved R-12 substitute for cars, which is just R-134a
with a little N-butane (and R-124 to mitigate flammability) thrown in
to cause it to work in mineral oil.  Performance is unknown with this
blend, since it is not yet on the market (FRIGC).  R-134a boiling point is
-15F and R-12's is -21F, so R-134a dropped in to a R-12 system is going
to have lower capacity (not counting the oil problems).  Adding N-butane
(B.P. 31F) and R-124 (B.P 12F) is going to make the capacity still lower,
but it will keep the head pressure down and the critical temp up.
They could have made a better refrigerant by using isobutane (B.P. 10F)
instead of N-butane, but that would have infringed on US patent
4,482,465 (Gray/Phillips-66).

There is some flammability risk for running pure hydrocarbons
(propane/butane, etc) in automotive A/C.. but it is pretty small.
OZ-12 (propane/isobutane) was installed in 50,000 cars with no
fire/safety problems reported.. until somebody "rigged" a controlled
demo, where 3 cans of it were released (took several tries) in a sealed
car passenger compartment, and recirulated until the correct fuel/air
mix was obtained.. and BOOM.. it did blow up.  Film at 11.. went to
CNN, etc.. which pretty much got it banned.  Using the fear of fire
in a non scientific manner to fear-monger the public.. Remember the
Hindenburg, the Pinto, The side mounted Pickup truck gas tanks, etc..
(remember the rocket engine ignitors?? on the truck blowing up?)

The A/C only holds 1.5lbs or so of propane/isobutane.  The gas tank
holds over 100lbs of gasoline.  Oil, brake fluid, transmission fluid,
power steering fluid, are all EXTREMELY FLAMMABLE/EXPLOSIVE when they
drip on hot enging/exhaust components. Hydrocarbons have to be at a fuel/air 
ratio of roughly between 2% - 8% by volume in air in order to ignite.

In a hose break/leak, propane/butane dissipate rapidly, gasoline
hangs around, fuming, waiting for an ignition source.
R-12 systems contain approx 10-15% by volume of mineral oil, which
is dissolved in the refrigerant.  A line rupture creates in "oil fog"
which can be quite explosive.  A jet of R-12/oil mist leaking can be
ignited (I have a pix) and does sustain fire (looked like a flame-thrower).
That is why "those in charge" are VERY CAREFUL to specify flammability
specs WITHOUT the oil present, rather that what is really found in
a car A/C.  When you include the compressor oil, all the refrigerants burn.

Also, many common "tire inflator/sealer kits" use propane
and butane, and it is mixed with AIR UNDER PRESSURE in a TIRE.. and
this IS A BOMB by definition.  How come nobody raises much ruckus over
tire inflators, R-12 and oil burning, etc.  Those things do not have
the power to prevent the sale of millions of "extra" new cars like the
alternative refrigerants do (when the R-12 is gone). R-134a does become
flammable at just above atmospheric pressure (5 PSI).  There have been
reports of R-134a explosions in refrigerant lines/compressors.. Workers
unsoldering lines (had air/R-134a in them), after letting out the 
refrigerant, built up a small positive pressure, or the burning of
the oil at the joint raised the local pressure above 5 PSI, and blam.
Go figure for yourself.


>>Even some stationary equipment mfgrs are reporting problems with NEW
>>R-134a equipment (refrigerators, etc).  Some equipment has been
>>recalled.  We have even heard of a company suspending production
>>on new refrigerators until R-134a/oil problems can be worked out.
>
>Well, undoubtably true, but that company has to address the problem
> quickly or lose the market. York, Tecumseh and Sanden have R134a
>compressors in the market here, and several systems manufacturers
>supply the OEM installations on new cars.  

How many car makers'
production lines/service shops will take the care and scrupulous
techniques that a scientific lab does when building or servicing
R-134a systems or retrofits.  3 years ago, I visited a dozen or so
air shops, using recycled R-12.. Every single one of them had "wet"
moisture indicators on their recyclers.. All but one of their vacuum
pumps failed to reach a micron vacuum (< 1000 microns is needed for
moisture removal before charging). Asked them when they changed
driers in their recyclers, and they said "what driers" and on the
pumps, "what pump oil", we use ATF transmission fluid for that!

What happens when production lines stop for awhile with "open"
A/C systems (drier soaking up water).. and shoddy service techniques
are applied to oils which are 10X or 100X more hydroscopic than 
5GS?? go figure...


>>Under the hood, radiator temps often hit 220F or so.. Since the
>>condenser is bolted next to the radiator, it sometimes sees these
>>temps also (I have measured condenser temps on an an instrumented
>>vehicle).  The "critical" temp of a gas, is the temp at above which

>Yup, these, and many more,  are discussed in the above articles
>- along with the techniques to eliminate/minimise the problems.
>There have been plenty of successful retrofits on a wide 
>range of vehicles. I didn't say there wouldn't be problem,
>but it seems the solutions are arriving thick and fast.

Has anybody wondered if massive retrofit failures are the "solution"??
Gets lots of service business.. then gets the service (3rd party)
out of business when they fail after 6mo-year.. "You should have
gone to the dealer all along..."  Now with unservicable A/C, consumers,
say "screw it", and trade up for a "new car".. 130-150 million R-12
cars out there.. go figure...

>>R-134a needs a much larger condenser due to this, and it located
>>away from the radiator (may not be possible), and beefed up
>>radiator fans to suck in more cool air than for R-12.  Retrofitted
>>R-12 systems are not likely to have large condensers/more air 
>>flow.. so they will have very poor low speed/stopped performance.
>
>This is discussed at length in the Automotive Engineer article,
>noting that the operating pressure of correctly retrofitted systems
>is about 15% higher. They note that parallel flow condensors can
>be used where space is a problem, and that Ford plans modications
>to the electric fans for front-drive cars. The cost-effectiveness of
>the upgrade depends on the price of such aftermarket modifications
>and the auto manufacturers recognise this. Condenser effectiveness
>depends on airflow. These people aren't bunnies, their retrofits are
>likely to meet their target specifications for performance and price.

Lots of room needed for beefing up things, no space in many compact
cars.. this means dozens of "custom" condensers need to be designed,
with custom fans, baffles, etc...a real integration problem. Plus
then you have the chloride/moisture problems to deal with.. How many
are going to do a "correct" retrofit, where everything which touches
refrigerant is replaced?  About $1500 or more incl labor.. That one
solves the residual chloride problems. Esters don't have as good of
lubricity as do the Minerals or PAGs..

>>Zeotropic blends (R-400 series refrigerants) can extend the
>>active phase change area of the condenser, thereby increasing
>>performance of the system provided operating conditions are met.
>
>True. But each retrofit alternative has its own problems, and currently
>the best thing going for R134a is the widespread utilization of it as
>OEM systems in new cars. I'm not trying to imply anything about your
>product, but for many reasons I'd prefer to see flammable refrigerants

(R-406A is not participating in the automotive sector)

>initially introduced in carefully evaluated  OEM systems on new vehicles.

Europe is using hydrocarbons now in new mfgr..  The main problem with
alternatives, is the damage to the pocketbooks of Detroit.

Why is Australia using MP52 (R-401C) for retrofits instead of R-134a?
It runs in Alkylbenzene oil which is very similar to Mineral oil
so it has no problems with PAG/Ester oil breakdowns. No major auto 
companies there or too few people to boycott MP52 there??


--ghg

From: ghg@freedom.ecn.purdue.edu (George Goble)
Newsgroups: rec.autos.tech
Subject: Re: A/C converson from Freon to R134- Necessary?
Message-ID: <398cma$ngn@mozo.cc.purdue.edu>
Date: 2 Nov 1994 15:53:46 GMT
Organization: Purdue University
Lines: 352

In article <B.Hamilton.85.2EB7764F@irl.cri.nz>, B.Hamilton@irl.cri.nz (Bruce Hamilton) writes:
> Well, it seems a raw nerve was accidentally exposed....

Lots of Raw nerves.  Esp on the Ford Driers and Spring-Lock connectors..

> >Fact of life:
> >Many major publications RELY on heavy advertising from the auto industry.
> >Like Millions of $$$ in advertising.
> >One cannot cut off the hand which feeds them.
> >These publications CANNOT print things which tick off the auto
> >industry (i.e. good things about blends, bad things about R-134a, etc)..
> >If they did that, all the big three + Japan would yank ALL their
> >adds.. for many months, causing the publication economic ruin.
> 
> One problem with this conspiracy theory is that  I've previously quoted
> similar articles from non-automotive journals, including the "Looming
> Ban on Production of CFCs, Halons Spurs Switch to Substitutes" from
> Chemical & Enginnering News Nov 15 1993 p12-18. "Ozone-Friendly
> Cooling" Popular Science July 1990 p57-63. "Replacing CFCs:The search
> for alternatives" Ambio Oct 1990 p329-333. HFC producers could also
> conspire

HFC producers also do conspire.. but not nearly to the degree 
as the big 3 American Auto companies..Also the big HFC companies
and the big 3 auto companies cross own whole bunches of eatch other's
stock.  Popular Science/Mechanics are majorly funded by auto
AD...as well as are most of the auto type mags...We typically see
a "Press Release" from Ward Atkinson of MACS first.. and then laugh
as it filters through all the mags.. almost same exact words, but
they change the author typically..One or two "non-aligned" rags
here and there will fight it..  They often get run out of business.

> Besides, GreenPeace has been strongly lobbying for the banning of
> R134a and its replacement by hydrocarbons, the lobbying is not all
> one-sided...

Almost nobody "in control" listens to Greenpeace in the US..
There is way too much money to be made off HCFC/HFC's than to use
hydrocarbons.. (even in "approved" designed for new mfgr..)

Even if new auto production did use engineered systems for 
hydrocarbons and all the hysteria was overcome.. they would
not happen over here.. since an auto recharge only uses
about $.50 of product.. Where as the same recharge can be
marked up to $200-$300 for blends/HCFCs/CFCs/HFCs...

> ....
> >Hindenburg, the Pinto, The side mounted Pickup truck gas tanks, etc..
> >(remember the rocket engine ignitors?? on the truck blowing up?)
> 
> No, the flames weren't visible down here. :-)

The video had to be freeze-framed, and single stepped.. GM did that..

> According to Automotive News. Nov 8 1993 p1&45.
> "Late this summer, International Association Arson Investigators
> conducted tests with as liitle as 5.5 ounces of the OZ-12 material
> introduced into vehicle interior. "When the ignition source was
> activated, the result was an explosion that blew the windows
> out of the car," said a source with the State of Florida.....
> The air conditioner's evaporator, located in the firewall, would
> provide a possibleentry point for the material into a vehicle cabin."

We have seen lab tests create 10 foot fireballs from around 2oz of
R-12/oil mixtures..but as the above trials.. the probability of
real danger in real life (the validity) is very very very small..
One can pretty much design a test to show about any result as
long as you know what the outcome should be before the test is
designed..

> I've previously said that I accepted these trials probably weren't
> valid, but you continue to berate me... 

Not berating you, just the auto industry over here..sorry it wasnt
directed at you..

> >The A/C only holds 1.5lbs or so of propane/isobutane.  The gas tank
> >holds over 100lbs of gasoline.  

This does not mean I am rooting for propane/isobutane refrigerant.. only
point out observations of things which have happened..and using that
as a worst case to show how almost all the harping on flammable refrigerants
is much ado about nothing., besides, doesnt NZ have zillions of propane
powered vehicles?

> >Oil, brake fluid, transmission fluid,
> >power steering fluid, are all EXTREMELY FLAMMABLE/EXPLOSIVE when they
> >drip on hot enging/exhaust components. Hydrocarbons have to be at a fuel/air 
> >ratio of roughly between 2% - 8% by volume in air in order to ignite.
> 
> All of which are located appropriately by the engineers designing the vehicle,
> taking due notice of the physical properties of the internal fluid. If they
> get it wrong and locate the gas tank where it can be hit, or make fuel
> pump diaphragms that  expand/shrink  due to gasoline aromatic/olefin
> concentration changes - resulting in major sprays of pressurised gasoline
> over the exhaust and alternator, they soon rectify it. In this case a 
> non-flammable refrigerant is being replaced by a flammable one
> in an existing system.
> 
> >In a hose break/leak, propane/butane dissipate rapidly, gasoline
> >hangs around, fuming, waiting for an ignition source.
> >R-12 systems contain approx 10-15% by volume of mineral oil, which
> >is dissolved in the refrigerant.  A line rupture creates in "oil fog"
> >which can be quite explosive.  A jet of R-12/oil mist leaking can be
> >ignited (I have a pix) and does sustain fire (looked like a flame-thrower).
> 
> True, I didn't say it couldn't  - however I don't have statistics on the
> number of R-12/oil fires, However I suspect the number is fairly low.

The 50,000 cars which used propane/isobutane didn't have any
reported flammability problems I heard either..

> Burning R-12 also produces toxic fumes, but let's put it this way -
> how many R-12 service people have you seen immolated using the
> flame copper halide, or heated Pt electronic leak detectors to test
> R12 systems. ( and yes, I'm aware the Cu flame test isn't appropriate
> for R-134a ). You must be aware that one of the major opponents to
> OZ-12 was the Mobile Air Conditioning Society - " The use of flammable

Try this one.. Discharging or leaking R-12 gets stucked into the air
intake of a running engine.. and "white smoke" pours out of the
exhaust...(this happened locally during service).  R-12 decomposes
in the engine to HF & HCL both wicked substances.. fortuneately
they realized what happened and abandoned the place in a hurry..

> ....refrigerants poses safety concerns to the technicians servicing
> mobile air-conditioning systems" states an October 1993 bulletin from
> MACS. They're not bunny Usenet posters like I apparently am.

MACS is 700 people trying to control the destiny of 400,000
air service technicians..

> >That is why "those in charge" are VERY CAREFUL to specify flammability
> >specs WITHOUT the oil present, rather that what is really found in
> >a car A/C.  When you include the compressor oil, all the refrigerants burn.
> 
> You know as well as I, that the Test Method specified by the US Department
> of Transportation as the procedure for determining whether a compressed
> gas is classified as flammable or nonflammable is ASTM-E361, and has been
> for a very long time. If you want some data, refer " Flammability of 
> alternative refrigerants" Robert G Richard, Ian R Shankland. ASHRAE
> Journal April 1992 p20-24. Table 4. Refrigerant Flammability
> Material, Flammable Range, temperature, Ignitionsource
> Propane, 2.1-9.6, RT, Match
> Butane, 1.5-10.1, RT, Match
> isoButane, 1.7-9.7, RT, Match
> R-134a, none, RT, Match.

I think the test is ASTM E-681, not E361 and it deals with gasses.
I have referenced the above paper in a paper I co-authored last year.
Many halo-carbons (like R-142b, R-32, etc) have very "ragged" upper
flame limits, and are very difficult to determine.. since they
wont stay ignited.. Although R-142b (chlorodifluoroethane) as listed
as "flammable gas" in the US.. One cannot ignite a stream of it
vented from a tank.. In a "liquid spill", it can be make to burn
a little bit when ignited from a propane torch, but it goes out
by itself..A weird case: flammable but has no "flash point"..
The E681 has existed for a long time.. The point is that the people
"in control" chose to use E681 on the refrigerant ONLY.. verses E681
or similar test on refrigerant+oil mixture what is found in a real
life situation..  If refrigerant+oil was used, about anything would
burn, and it could not be used as a tool to keep out blends, etc..
Refrigerant+oil flammability is also "hush-hush" in the stationary
industry..

There are very many degrees of flammability , like the case of R-142b
above to hydrocarbons and to things even worse like acetylene and
ethers (4-100% and 5-35% in air).. acetylene will continue to
burn (polyermize with no oxygen present once started).

The public lumps them all into the "explosive" category.
For instance, we know from the movies, that a small fire
near the filler neck of a car's full gas tank results
in the explosion of the whole car as well as the filling
station going up too.  Fires burn back up their fuel stream
until they reach the tank.. and boom....

The movie would not be fun.. if a small 2-3 inch flame formed
at the filler neck and was batted/blown out by the pump person..
The tank cannot explode since it does not contain 92-98% air
to put the gasoline in it's flammability range..

Take a big gasoline liquid spill, getting under all kinds of things,
producing fumes, etc... then igniting later.. now you have a scene
(e.g. Texas river fires were a few million gallons of gasoline got
released due to ruptured refinery pipelines from floods before
it went off..

> ( Yes they do use the electrically-activated match ignition source 
> specified in ASHRAE Standard 34-1989 ( because many of the

ASHRAE even argues over the type of "match"..I as involved in some
"paper match" vs "kitchen" (strike-anywhere) match discussions..
The current standard is 34-1992 I think now.

 If you want to see a paper  I co-authored, and if you have Mosaic, check 
out "http://ghg.ecn.purdue.edu" (my homepage), skip about 3/4
the way down.  The first part of it is dumping Liquid Oxygen
on BBQ grills to light them. I may scan in the R-12 oil fire pix.
next week if I get time.

> halocarbons are difficult to ignite - maybe the OZ-12 Arson
> Investigators above didn't :-) ).
>    
> >                                                 R-134a does become
> >flammable at just above atmospheric pressure (5 PSI).  There have been
> >reports of R-134a explosions in refrigerant lines/compressors.. Workers
> >unsoldering lines (had air/R-134a in them), after letting out the 
> >refrigerant, built up a small positive pressure, or the burning of
> >the oil at the joint raised the local pressure above 5 PSI, and blam.
> >Go figure for yourself.

I am not saying R-134a is bad, but it is being passed off as
"never" flammable, rather than being warned about flammable 
above 5 PSIG.. If the tech knows the real story, then proper
precautions, such as not allowing a small residual pressure
buildup or a dry nitrogen purge first would be taken.
R-22 and almost all other HFC/HCFCs when mixed with large
amounts of air under pressure (50 PSIG or so) will burn explode..
But this is not commonly encountered.  R-134a/air (if used for
pressurized leak testing) can be explosive if a torch heats
the outside of a pipe for instance. Not a real problem and
easy to avoid, just one has to be aware of what is going on.

> Refer above, the service technicians seem to prefer R-134a for
> retrofits rather than HCs, so would I. You may choose otherwise...
> 
> >How many car makers'
> >production lines/service shops will take the care and scrupulous
> >techniques that a scientific lab does when building or servicing
> >R-134a systems or retrofits. 
> 
> Several  makers support R-134a ( and I've previously posted on the
> data on the 2 years/million mile ICI trials - which also found none of the
> vehicles' owners took ICI up on their offer of a free retro-retrofit back
> to R-12 at the end of the trials). Volvo's low-priced scheme ( $45 parts, $21 
> R-134a, estimated $200 for labor ) was intended to encourage owners to 
> take the environmentally  beneficial option,
> 
> 
> >What happens when production lines stop for awhile with "open"
> >A/C systems (drier soaking up water).. and shoddy service techniques
> >are applied to oils which are 10X or 100X more hydroscopic than 
> >5GS?? go figure...
> 
> Come on, these refrigerants probably still aren't as hydroscopic as 
> glycol brake fluids, and the boiling point reduction caused by water
> is far more safety critical ( sudden, total loss of brakes ) - if necessary 
> Toyota etc can show the US industry hoew they currently do it.
> We both know production lines can operate to produce low moisture
> systems.

While not as "safety related", A/C systems are much more easily
ruined by a few 10s to 100ppm  of moisture.. All HFC/CFC/HCFCs
break down slowly into acids from residual moisture.. -134a
has a second strike against it, in the jact that it's oils
PAG & POEs are moisture sensitive as well.. I doubt that 100ppm
of moisture in glycol brake fluid will depress its boiling
point all that much.

> ....
> >Has anybody wondered if massive retrofit failures are the "solution"??
> >Gets lots of service business.. then gets the service (3rd party)
> >out of business when they fail after 6mo-year.. "You should have
> >gone to the dealer all along..."  Now with unservicable A/C, consumers,
> >say "screw it", and trade up for a "new car".. 130-150 million R-12
> >cars out there.. go figure...
> 
> Conspiracy theory - bad news travels fast. Long term players will
> provide long term solutions. I think I initially quoted from the July
> 1994 ( Car & Driver? ) article by Patrick Bedard " As carmakers do
> more testing, retrofits seem less of a nightmare..."

About a year ago, the MACS newsletter printed something to the
effect that GM retrofitted 60-some vehicles to R-134a, and in
5 months had > 25% compressor failures (using PAG oil).
I can't believe MACS printed that. then a total hush-hush on it.


> >>         These people aren't bunnies, their retrofits are
> >>likely to meet their target specifications for performance and price.
> 
> >Lots of room needed for beefing up things, no space in many compact
> >cars.. this means dozens of "custom" condensers need to be designed,
> >with custom fans, baffles, etc...a real integration problem. Plus
> >then you have the chloride/moisture problems to deal with.. How many
> >are going to do a "correct" retrofit, where everything which touches
> >refrigerant is replaced?  About $1500 or more incl labor.. That one
> >solves the residual chloride problems. Esters don't have as good of
> >lubricity as do the Minerals or PAGs..
> 
> We've been down this path ealier this year. the chloride/moisture 
> problems can be overcome with appropriate selection of formulation
> and operational procedures. A "correct" retrofit doesn't involve a
> complete replacement. Refer above for the Volvo, ICI examples; 

A "correct" retrofit may involve a trade-in of the vehicle for
a "new" R-134a system, which won't have the chlorides to contend with.
Also a "new" car will likely have 30% oversided condenser and increase
airflow to restore capacity to that which R-12 would give.

> and I'll repeat a quote from the above C&EN article " In 1991, the auto 
> industry estimated retrofitting costs would range from $200-$1200 per car, 
> depending on the make, model, and year.... But after a few years experience 
> withretrofitted vehicles, it appears the high end of the cost range may
> have ben overestimated".

I have heard reports of users so unhappy with R-134a retrofits that
they want to illegal blends after removing the R-134a and were happy.
Almost any zeotropic blend whether it be propane/butane, R-400
series refrigerants would offer a great capacity increase with a
marginal condenser.. Anything but hydrocarbons stuck back in a former
R-134a system with PAG oil would pretty much trash the oil in short
order I would think.

>  ...
> >Europe is using hydrocarbons now in new mfgr..  The main problem with
> >alternatives, is the damage to the pocketbooks of Detroit.
> 
> I'm sure Detroit will listen carefully, especially if you offer complete
> indemmification for all A/C fire claims. Of  course they might want
> to know that you have the $ to back it up.  I've consistently said
> that I have no problem with HC designed/tested OEM systems.
> 
> >Why is Australia using MP52 (R-401C) for retrofits instead of R-134a?


This (R-401C) was brought up at the 1994 CFC and Halon alternatives conference
which went on last week in Washington DC..I was told this on the phone.
My proceedings just arrived (it is 4" thick).  I will try to track it
down more.

I have also noticed that at least some of the "CFC" conferences are
"rigged", esp in the automotive area.  In the past, papers which
were not "yea 134a" got rejected, after acceptance. This has happened to 
me & Dupont.  I had a paper accepted for a 1992 CFC conference on a 
refrigerant blend by Dr. Stephan Anderson, chief CFC scientist at the USEPA,
and the auto-industry managed to kill it as a "mistake", we forgot
about it, etc..  Ward Atkinson then gets quoted by the press
(Arizona Republic), "nobody has come up with a breakthrough, so we
will have to retrofit millions of cars to R-134a"... Ward Atkinson
was the session chair at the particular conference. Ward Atkinson
is the technical advisor for MACS/SAE as well.

Dupont has had papers on MP52 (now R-401C) taken out of conferneces also.
MP52 is on the EPA approved list in the US, but they appear to have
been "boycotted" by the auto industry into not selling it here.
MP52 does not need unstable PAG or POE oils.. It needs 80% alkylbenzene
oil, which is similar to mineral oil and is much more stable then
PAG or POE, so MP52 won't be destroyed by trace chlorides, mineral oil,
CFC-12 residue, etc...

Also MACS says "only 1 refrigerant (134a)" so service wont get confused,
but 47 types of PAG compressor oil are OK... go figure..

--ghg

From: ghg@freedom.ecn.purdue.edu (George Goble)
Newsgroups: rec.autos.tech
Subject: Re: A/C converson from Freon to R134- Necessary?
Message-ID: <3990b1$3o9@mozo.cc.purdue.edu>
Date: 2 Nov 1994 21:29:05 GMT
Organization: Purdue University Engineering Computer Network
Lines: 139

In article <B.Hamilton.127.2EB7F39C@irl.cri.nz> B.Hamilton@irl.cri.nz
(Bruce Hamilton) writes:

>In article <396a12$4r5@mozo.cc.purdue.edu> ghg@freedom.ecn.purdue.edu
>(George Goble) writes:
>
>>Remember the old pre-computer cars with carbs?  How many times
>>did people inadvertantly "flood" them by pumping the throttle
>>too much?  Remember you can to "floor" 'em and keep cranking
>>until the over rich mixture was sucked into the engine and it
>>leaned down until the upper flame limit was reached and the
>>car started?  Remember the smell of gasoline fumes in the
>>passenger compartment?  How much gasoline fumes do you think
>>where under the hood then?  Starter solenoid/commuter sparking..
>>How many "flooded" cars actually blew up?  Must not have been
>>very many or we would have had a national outcry.  Why is propane/
>>butane refrigerant gonna be any worse if it is leaking.  To even
>>approach flamability limits, the leak has to be pretty severe
>>(few hours or less)..
>
>It may just have something to do with the fact that liquid gasoline
>doesn't burn, only the vapours it gives off. At all temperatures 
>above -35C it produces sufficient vapours to burn in the closed
>cup Flash Point test. But in real life sometimes the warmth and
>air movement isn't available  to generate sufficient vapour, _and_ 
>mix it with air to yield a flammable mixture.  If the mixture was
>only flammable after being leaned down and mixed in the engine
>there wasn't a great chance in the relatively static air in the engine 
>compartment of a stationary car. 

Car is "flooded" since mixture is too rich in the carb..
outside the carb, under the hood, and possible in the
passenger compartment.. it may be in the flammable range..
remember you can smell it.. one may have raw gas dripping 
out of the air cleaner or such now.. What if you get a "backfire"
while cranking?  The starter turning the radiator fan should
stir it up quite fine.

>Your product _is_ under pressure,  _and_ will mix with air to produce a 
>flammable mixure without additional heat. Gasoline needs to be 
>vaporised and mixed with air.  You must be aware that winter gasolines are 
>much more volatile than summer - to assist winter starting/prevent summer
>vapour lock - although the EPA is planning on reducing the volatility
>for environmental reasons. Correctly-formulated volatile winter gasolines 
>( with more propane, iso-butane, n-butane :-) ) make starting much easier
>on carburetted cars. If you don't believe me, take some at 20C , shake it up,
>vent the can, repeat several times until pressure no longer builds up. 
>Then try to cold start a carburetted car with that fuel. 

It is a bitch.. take a spell of local winter at -10 or -20C..
so "winter gas" has lots of isobutane/butane in it.. filling is no
problem.. Now we get a sudden +10C day (50F or so)..
Can't even fill a tank or Jerry Can.. stuff is foaming so bad,
you can see all that butane/isobutane boiling out..
takes forever.. besides you may be losing 5-10% of the product
which boils off on the +10C day you dont get to use!
Shell's gas last year was real bad on winter gas on warm day!
I have believed you for years on this one.

>Now as your mixture is similar to LPG, remember those stories of LPG 

You have me mixed up with "OZ-12".  I was just using an extreme
example such as OZ-12 to show worst case scenarios.. and very
little if any flammability problems surfaced.. so things which
are much less flammable should have no problem.. Back in 1989
I made one batch of what would later be known as OZ-12 by others..
It was 79% propane and 21% isobutane.. I ran it in a car for 3 months
and abandoned it.. worked fine.. but friends of mine whom jump out
of planes every weekend, refused to ride in the car.. people
were joking about about 1.5lb of hydrocarbons leveling a parking
garage, etc...  Because of this riddicule I dropped work on 
hydrocarbons...

My current mixture, R-406A, is only (by weight) 4% R-600a (isobutane),
and 41% R-142b (chlorodifluoroethane), and 55% R-22 (chlorodifluoromethane).
Worst case fractionation scenarios are cold temps, like -20C, and
around 90% vapor leaked off... In this state it is around 3% isobutane
(max, usually 2), around 13% R-22, and 84% R-142b.  Continuing the
leakout to 100% results on pure 142b at the very end.  Near the
80% vapor leakout point R-406A may exhibit very weak flammability, but
no flash point.. Pure R-142b also has very weak flammability and
no flash point.. The remaining R-22 near the end more than 
midigates the effect of 2-3% isobutane.  Opening a tank, for
a slow vapor or liquid leak, and a propane torch, worst case
fractionated R-406A will not light up.  Taking a "puddle" (worst case) of 
liquid and a propane torch, one can get it to ignite, but it
goes out after a second or two.. the decomposition products
quench it. There is still no "flash point".  The heat of combustion
is around 1/10 of that of hydrocarbons.. "rate" of combustion
(pressure rise) in an E681 test.. are much much lower..
Ammonia burns much faster (LFL-UFL 15-25%) and it is US-DOT
nonflammable.

We gave up on on automotive airconditioning because of all the
political fighting from MACS and the auto industry in the US..
Whenever something gets close, they have to power to change
the playing field (rules) at will.. Much of the refrigeration and A/C
sections of the US "Clean Air Act" were drafted with their "assistance".
"They" even got President Clinton to get Dupont to crank out
an extra year of R-12 production..after the EPA refused.. so
you know how powerful the auto industry is.  They also boycotted 
an EPA approved blend, MP52 (R-401C), into not being marketed
in the US for autos.  If the auto industry can do that to a $33 billion
company, there is no chance for the "little guy" in an arena
like that.. It is not just an unlevel playing field, the playing
field is inverted.

>leaks in caravans with LPG stoves? :-) , and how they exploded 
>when ignited - leading toall those regulations about LPG installations on 
>mobile installations. I don't know about the US, but here in NZ the
>safety requirements for the structural integrity ( in an accident) 
>of road and rail tank wagons for gasoline and LPG are hugely
>different - something to do with an LPG or propylene? road tanker
>tanker and the almost instant conversion of a holiday camp site in Spain 
>into a crematorium, if I recall correctly.    

I remember the tanker (propane), wasn't it in Mexico, it
got 300-500 people?

>Your comment about "to approach flammable limits"  obviously
>depends on what volume of air you intend to make into a fuel/air
>bomb. The size of a leak depends on the mechanism, I've never
>seen a large "verandah" leak through bundy tubing, but then I've
>never seen a small "pipe/hose  fracture" leak either. YMMV. 
>OZ-12 auto A/C conversions represented <0.04% of the R-12 fleet,
>and the service industry organisation was against HC refrigerants.

Portions of the Florida service industry were "for" OZ-12.. and
business was going like gangbusters for 2 or 3 months.. before
the rigged explosions.

Lots of people are still using it "illegally".. They were supposed
to have is removed and replaced with R-12.. but they decided to
keep it even with all the flammability hoopla.. they know you
have 100lbs of gasoline onboard and made their decisions..


--ghg

From: ghg@freedom.ecn.purdue.edu (George Goble)
Newsgroups: rec.autos.tech
Subject: Re: A/C converson from Freon to R134- Necessary?
Message-ID: <39g32m$g13@mozo.cc.purdue.edu>
Date: 5 Nov 1994 13:58:46 GMT
Organization: Purdue University Engineering Computer Network
Lines: 171

In article <B.Hamilton.87.2EBA8897@irl.cri.nz> B.Hamilton@irl.cri.nz
(Bruce Hamilton) writes:

>In article <398cma$ngn@mozo.cc.purdue.edu> 
>ghg@freedom.ecn.purdue.edu (George Goble) writes:

>>> >The A/C only holds 1.5lbs or so of propane/isobutane.  The gas tank
>>> >holds over 100lbs of gasoline.  
>>This does not mean I am rooting for propane/isobutane refrigerant.. only
>>point out observations of things which have happened..and using that
>>as a worst case to show how almost all the harping on flammable refrigerants
>>is much ado about nothing.,
>
>Oh..... Really?....
>I can't see how I could have otherwise interpreted it...
>I've obviously misunderstood your position :-(
>I'm now confused, Gregory has kindly posted the federal
>registor, and lists GHG-12 as a zeotropic blend that can
>become flammable. From earlier JdA raves I thought you
         ^
	"weakly flammable"

I made a video tape showing this when the Safety paper was
presented last summer..  I may digitize some segments 
showing "weak" flammability and add them to my homepage if
anybody is interested..  There is also a comparison to
lighting up 8oz of propane and kicking it over.
R-406A is undergoing further safety testing/classification
at UL and other safety testing organizations.  Work is also
underway on risk assesments.

>were also pushing a totally HC refrigerant?.

JdA seems to have vanished from the net a couple of months back..
nobody knows what happened to him for sure.  Back in 1989, JdA
made a net posting about propane & butane:


|From pur-ee!mentor.cc.purdue.edu!purdue!gatech!emcard!stiatl!rsiatl!jgd Sat Oct  7 18:25:30 EST 1989
|Article 766 of sci.energy:
|Path: en.ecn.purdue.edu!pur-ee!mentor.cc.purdue.edu!purdue!gatech!emcard!stiatl!rsiatl!jgd
|From: jgd@rsiatl.UUCP (John G. De Armond)
|Newsgroups: sci.energy
|Subject: Re: Refrigerator efficiency (was Re: energy sources discussed)
|Message-ID: <220@rsiatl.UUCP>
|Date: 4 Oct 89 07:42:46 GMT
|References: <16209@brunix.UUCP> <4432@cbnewsh.ATT.COM> <4516@internal.Apple.COM>
|Reply-To: jgd@rsiatl.UUCP (John G. De Armond)
|Organization: Radiation Systems, Inc. (a thinktank, motorcycle, car and gun works facility)
|Lines: 178
|
|[much stuff deleted]

|>
|>NH3 can be nasty stuff, hydrocarbons are flamable, etc.

|Plus the hydrocarbons, such as butane and propane are not too hot as 
|refrigerants.
|
|[stuff deleted]

------
I went out in the spring of 1990, and ran a mixture of 79% (wt)
propane/21% isobutane in 1 car.. and it ran fine and posted this
to the net.  Suddenly, JdA became a raving supporter of
HC refrigerants, and touted them for 4 years.. Much later somebody
else "invented" OZ-12, which was pretty much the same thing.
I gave up work on this due to the flammability 2 months later.

Other's on the net, seemed to accept the risks of HC flammability
and wanted to "roll their own" R-12 substitutes.  There was lots
of discussion about how to mix, charge, etc.. JdA was very active
in all that.  He also ran GHG R-12 substitute (R-406A) and touted
that..

In passing to a response on home mixing HCs for A/C, I mentioned a recipe:

Get 6oz can of isobutane camping fuel...
Get 16oz can of propane (for a torch)
crock up necessary plumbing to get the above into
a refrigeration gauge set. JC Whitney's sells Freon can side-tapper
which works on the isobutane.
Evacuate system as normal with a vacuum pump.
Charge in the isobutane
Charge in the propane.
This is approx the correct mixture and correct amount to
run an R-12 3lb system on a typical car.. No mixing, weighing, etc.
I assume no liability if you burn/blow yourself up.

JgA pushed this also.. and several net users did it, and it worked
and they seemed to be happy...

However, this has caused much of the public to wrongly equate GHG-12 or GHG-
R-12 substitute with being all hydrocarbons (i.e. OZ-12)
It is a neverending problem to set this straight.



>My position has always been that retrofits of highly flammable
>HCs  (OZ-12 ) into systems designed for non-flammable CFCs.
>I'm a little more ambiguous on blends such as R-406a  that can 
>become flammable, but as it has HCFC-22, and HCFC-142b -
>which both have higher GWPs than HFC-134a, it's likely to be 
>even more transitional than HFC-134a. 

R-406A was never intended to be anything else but a "transition"
to R-134a.. to keep CFC-12 equipment running until end of normal
life.. R-406A GWP is around 89% less then GWP of R-12, the
thing it replaces.  We are getting numerous inquiries from OEMs
(stationary equipment) who are having problems getting new mfgr
R-134a equipment to hold up and are thinking about using R-406A
until R-134a problems can be worked out.


>>Try this one.. Discharging or leaking R-12 gets stucked into the air
>>intake of a running engine.. and "white smoke" pours out of the
>>exhaust...(this happened locally during service).  R-12 decomposes
>>in the engine to HF & HCL both wicked substances.. fortuneately
>>they realized what happened and abandoned the place in a hurry..
>
>Well, if servicepersons had tried the same trick with OZ-12, I'd guess
>the chances of ignition in the engine compartment before the refrigerant
>got to the intake would be reasonable - they may have received assistance
>abandoning the place.  I'm aware of the HF and HCl problem, as is any 
>refrigeration/A/C serviceperson.  

Somebody tried this on the net, blowing off a propane/isobutane full
charge with the engine running on a junk car.. with fire ext
handy..  nothing happened. quite to his amazment I am sure..

>>Dupont has had papers on MP52 (now R-401C) taken out of conferneces also.
>>MP52 is on the EPA approved list in the US, but they appear to have
>>been "boycotted" by the auto industry into not selling it here.
>>MP52 does not need unstable PAG or POE oils.. It needs 80% alkylbenzene
>>oil, which is similar to mineral oil and is much more stable then
>>PAG or POE, so MP52 won't be destroyed by trace chlorides, mineral oil,
>>CFC-12 residue, etc...
>
>I suspect alkylbenzene oils will be shown to produce toxic 
>compounds during use, and will have to be disposed of as
>hazardous waste :-)


I haven't seen this to be the case (yet).. I will keep watching..

>>Also MACS says "only 1 refrigerant (134a)" so service wont get confused,
>>but 47 types of PAG compressor oil are OK... go figure..
>
>True, but my impression was that the MACS main concern was safety.
>Also, the article I read quoted Simon Oulouhojian ( President and
>Excutive director ) of MACS.

MACS has managed to stop anything (but 134a) which has gotten EPA
approval for an automotive A/C retrofit refrigerant before it
got to market.. even if it was totally nonflamable and made by
companies worth tens of billions of $$$.  We subscribe to the MACS
newsletters and sometimes attend their meetings..

Before the creation of SNAP, we were at a MACS meeting in Orlando, Fl.
(jan 1993?)
Lena Nirk of the USEPA announced that the EPA had found nothing
wrong with any of the blends (MP52 and GHG) for environmental
reasons, and was getting ready to "approve" them.  She said they
only objections to blends were "business" reasons.

You should have heard MACS fume and blow their top on that one.
Four-five days later, and order came down from cabinet level to
the director of the EPA to "ban the blends".. go figure...



--ghg

From: ghg@worldserver.com
Newsgroups: rec.autos.tech,austin.autos
Message-ID: <6ot2qi$6h1$1@nnrp1.dejanews.com>
Subject: Re: R134A refrigerant
Date: Sun, 19 Jul 1998 15:19:46 GMT

In article <6ondoe$fsv$1@nnrp1.dejanews.com>,
  fred@inti.net wrote:

> In article <35AE26B2.41C6@the.sig>,
>   "S.L." <look@the.sig> wrote:
> > fred@inti.net wrote:
> > >
> > > >
>
> >
> >
> > Sweat equity during the retrofit is indeed the same... but you'll
> > definitely keep sweating afterward with R-134a, because the system will
> > take a big efficiency hit ;-)
>
>   I think it depends on the age of the vehicle. Vehicles built after 1987
[snipped]
> that was smuggled could be a questionable quality and could through
> hook and crook find its way into legitimate distribution channels
> with the U.S..
>
> > composition, being dominated by the lightest part of the blend. However,
> > the *liquid* portion does not significantly alter composition and
> > doesn't separate into layers (the blend components all dissolve into
> > each other- just like alcohol and water don't separate as a liquid mix),
> > and the vast majority of the charge (in terms of weight, not volume)
> > stays liquid with the system off.
>
>   The promoters of R-22 blends have stated that their containers have
> a "dip tube" in them to insure that any refrigerant drawn off is in a
> liquid state. That may be fine, but it is by no means an absolute assurance
> that the refrigerant was handled that way through all steps of the
> distribution process. What I would like to see are some tables that
> show the efficiency of the blend through various degrees of blend ratio
> alteration. If the "ideal" blend of R406a effectively mimics the properties
> of R-12, what happens and to what degree is performance is altered at
> various stages of blend composition??

All zeotropic refrigerant blends (R-400 series), Freeze12, etc. Must always
be transferred as a liquid, hence some put in dip tubes in cylinders to make
it's use easier. Manufacture of R-406A is check with a Gas Chromatograph..
Composition stays within 2% or so during using a large cylinder, which
is not detectable on performance.

> > They didn't do all that just because it was fun. They did it so that an
> > R-134a system would have a hope of surviving to 150,000 or 200,000 miles
> > and they wouldn't lose their shirts on warranty claims (and they've lost
> > quite a bit anyway)!  As I said, I have an R-134a OEM system, and it
> > works just fine at over 120,000 miles so I know all those changes worked
> > to some degree. The kits make it sound simple... but I've read the
> > instructions on the packages and I've looked at the oils and "stop
> > leaks" they supply with the kits. I GUARANTEE you that if you use one of
> > those kits according to the instructions, you will have a completely
> > RUINED A/C system within 2 years... maybe even within 2 DAYS, especially
> > if you live in the south where A/C is needed nearly year-round.  I've
> > seen LOTS of posts to www.aircondition.com/ wwwboard/retrofitting/ that
> > say "Help- installed retrofit and it worked for a week...."
>
>   I agree, those $15 dollar kits are a joke! But I still wonder about
> blends. When the CFC phase out became a reality, I have to wonder about
> R-22 blends. The engineers at Dupont, ICI, Allied-Signal, and ELF-Atochem
> aren't idiots, they surely must have looked at various blends as a viable
> replacement for R-12. Indeed they DID come up with various blended
> refrigerants for replacement of CFC's in stationary/industrial systems,
> but stopped short of blends for vehicular systems. But in the end, it
> seemed that only a homogeneous substance such as R134a was acceptable

All about money.  Dupont had R-401C (MP52) ready for cars, and it worked
well, provided that 80% of the oil was changed from mineral to Alkylbenzene.

We have heard that the auto industry told Dupont, Allied-SIgnal, etc, to
not make any blends for cars or face auto industry boycotts of their entire
product lines. 134a is the only "permitted" refrigerant under this order.
Dupont promply took MP52 off the shelves in the US.. It works well outside
the US though. They also aren't allowed to sell "blend components" to those
who might make automotive blends.. so we have to import everything..
This is serious restraint of trade.

The 134a plants of the "big boys" are losing about $1million/month due
to lack of demand for R-134a.  They probably used the R-12 used per season
in the late 80's to figure demand.  90% of the R-12 went to leakers and
service, 10% for new mfgr.  Barrier hoses on 134a systems and other measures
have almost stopped leaking, so the "90% for service" is much less, and
hence the overproduction of R-134a, the resulting "glut" in supply, price
wars, etc.. HC refrigerants, R-406A, and other blends (other than Freeze12
and FR-12 that are mostly 134a) are a threat to the wallets of the 134a
industry.

> or an HC substance such as a propane/isobutane was acceptable to the
> industry. HC based vehicular refrigerants have been sucessfully used
> for years in other countries with no problem, but the EPA has been
> steadfast in not accepting them because of their fears over the
> flamibility of HC's. There has plenty of evidence offered over the
> safety of HC's in vehicular systems, but the EPA has kept their
> heads stuck in the sand in regard to HC's despite the evidence offered.
> Indeed, the gasoline a typical vehicle carries is a far greater fire
> hazard, but the EPA seems to be blind to that despite the fact that
> even in a serious collision where the A/C is breeched, any escaping
> HC's will be gaseous and burn off harmlessly, but 75 litres of
> gasoline escaping from a breeched tank will lay about and cause a
> serious hazard. We've allowed the EPA to become lord and master
> over all our cooling questions, but we haven't demanded they account
> for their rulings on valid scientific grounding. We need to protect
> the environment and ozone depletion is a perfectly valid issue, but
> we are confronted with half-cocked government bureaucrats who got
> their jobs based on political merit and we consumers have to take
> it in ths shorts.

R-134a was $1000/30lb in 1992-1993, now $60/30lb.
It is all about money.. costs $.25 (+price of a can) to make a
HC refrigerant.. HC are in use outside the US.. no major liabaility
from fires has happened.  MACS "helped" the EPA SNAP division set itself
up and issue the first rulings for MVAC.  Look at how hard they fought
with OZ-12.  Now they are busy lobbying in HC illegal state laws now,
incase SNAP cant stop it.

> ........Fred

From: ghg@worldserver.com
Newsgroups: rec.autos.tech,austin.autos
Message-ID: <6ot476$8bt$1@nnrp1.dejanews.com>
Subject: Re: R134A refrigerant
Date: Sun, 19 Jul 1998 15:43:34 GMT

In article <35AD0FBB.41C6@the.sig>,
  "S.L." <look@the.sig> wrote:
> fred@inti.net wrote:
>
> > Blended refrigerants may be fine for stationary systems
> > that use hermetically sealed compressors and soldered copper tubing
> > between the evaporator and condensing unit, refrigerant egress is
> > usually not a problem with such systems. But vehicular A/C by their
> > very nature tend to be "weepy" and the question when using blends
> > in such systems is that the lighter components of the blend may tend
> > to exit the system first, thus altering the blend ratio to the point
> > where a significant loss of system performance is premature compared
> > to the use of a homogeneous substance such as R134a.
>
> It is true that R406a will alter its blend ratio and efficiency will be
> reduced if the system is leaky. But mobile systems don't HAVE to be

EPA tests on leaking R-406A, showed it still outperformed other
alternatives. You are so far ahead with 406A, and after extensive
leaking, you have about R-12 performance at that point.

> leaky (I have a 1966 Dodge that never had ANY A/C service until 1990).
> This is exactly why neoprene O-rings, compressor shaft seals, and
> barrier hoses are required with R-406a. R-134a also requires these
> modifications, simply because it will diffuse right through nitrile
> hoses and O-rings. One thing to note though, is that R-406a starts out
> *more* efficient than R-12. If some degradation occurs the system will
> still cool quite well. R-134a on the other hand is immediately 10-30%
> LESS efficient at cooling (depending on the system configuration) than
> R-12, and operates at much greater high-side pressures. Most R-12
> systems won't survive nearly as long on R-134a without seal or
> compressor failure as they will on R-12 or R406a.

R-406A works fine with nearly all of the original O-rings and seals.
The auto industry now is pushing a "light green" O-ring designed to
self-destruct in many blends, incl R-406A, and only work in 134a.
Money & politics.. Stick with older neoprene for R-406A.

> >    The other problem with R406a is that it can not be recycled, but
> > must be discarded as scrap. The SAE has never established any "J" standards
> > for R406a and as far as I know, there are no charge/recharge/recycle
> > stations available in the marketplace to handle this refrigerant.
>
> Incorrect. The manufacturer of R-406a will buy back any discarded
> refrigerant from its distributor network, and that includes directly
> from *you* if you bought your 406 from them (see
> http://www.autofrost.com/info/reclaimpol.GIF). They also supply
> everything you need to install and evacuate their refrigerant. (this is
> also true for the makers of most other substitutes). Refrigerants can be
> separated and re-used quite readily.
>
> > So if you use R406a, you'll have to handle it on your own or go back
> > to the shop that installed it in the first place. That could be a
> > problem if you're out on the road and your A/C system needs service.
>
> True enough. That is one thing you should consider when making the
> switch to ANY alternative refrigerant. What is not often said, but
> should ALWAYS be remembered is that the vast majority of AC shops WILL
> NOT TOUCH AN R-12 to R-134a CONVERSION EITHER!!  None of the respected

This is so true...

> A/C shops in this metro area will touch conversions (although some
> fly-by-nights will). They have no guarantee that all the R-12 was
> properly removed during the conversion, and WILL NOT risk contaminating
> their r-134a recovery system with R-12 because the results would be
> disastrous for their business. Cross contamination of R-134 into R-12 is
> a big enough hassle, but getting any R-12 into an R-134 system is DEADLY
> to the system, since the chlorine in R-12 will destroy the PAG oil used
> by OEM R-134a systems.

We have seen fly-by-night airshops buying R-406A, and then telling the
customer.. "no stinkin' blends, just R-12 and 134a".. They then install
R-406A illegally, no fittings, labels, etc,
and charge the customer for "R-12" and make a huge profit. Customer
does not know the difference.

> I'm a strong proponent of JUST STICKING WITH R-12 first and foremost,
> and I'm sure as heck not affiliated with any of the alternative
> refrigerant marketeers. There are problems with all of the conversion
> alternatives. But based on the research I've done, converting to R-134a
> (although it is the most common conversion done by A/C shops that will
> even DO conversions, and most of the really good ones WON'T...) is the
> WORST alternative. The system simply will not cool as it should because

This is so true.. There several paths that the industry could have taken,
all except the current one (yea 134a), would have resulted in better
performance and longer life of older cars..  This path ticks off the
public and early fails retro'd 134a systems, leading to a huge increase
in trade-in's for new cars.. All about money..

Good airshops in my area will not retro to 134a.. they use 406A or 12.

> the pressure/temperature curves of R-134a are so different from R-12,
> plus the excessive pressures generated on the high-side of the system
> may damage components designed for R-12.
>
> --
> Stephen Lacker
> Applied Research Laboratories, The University of Texas at Austin
> slacker@arlut.utexxas.edu (Remove the extra 'x' to mail me)


--ghg