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PLeon (Mechanical) (OP)
6 Jun 06 8:07
I find that all R134a systems are not providing cold air as fast as older R12 systems.  I remember R12 systems that would pump cold air withing seconds after start up.  Is this true or am I imagining things?
TIA,
Leon
stout1 (Mechanical)
6 Jun 06 10:08
I am no expert on this but you are correct.  R12 does cool better but is not good for the environment, R134a does not cool as well but is environmentally friendly.  I can notice a little difference but it doesn't bother me much, I just need to run the fan a little more now.  Hopefully someone will have more info than I do.  Have a good one.

Michael
swall (Materials)
6 Jun 06 11:38
Actually, the hunt is on for an R134a replacement because of environmental concerns.
Holyterror (Automotive)
6 Jun 06 21:56
Venting R134a comes with a hefty fine and/or jail time (just like R12).  In a little-known Armstrong Labs experiment, a subject was exposed to R134a for four and a half minutes before his pulse and blood pressure became nonexistant.  Miraculously, he was revived (CPR I believe), and given pure oxygen.  However, he and one other subject continued to experience dizziness and balance problems for six weeks following the experiment!  The other subject also experienced ringing in the ears over the same time period, and chest "fluttering" for the first two weeks.  The report was written six weeks post-exposure, so who knows if they ever recovered.

I'd be looking for a replacement too.
pennpoint (Mechanical)
6 Jun 06 23:56
Holyterror
I refuse to bite on that....

Best regards
pennpoint

Holyterror (Automotive)
7 Jun 06 0:24
Then chew on this:

Armstrong Labs Report (can't link directly to the PDF, click on Toxicity Reports at the bottom of the page)


This report was removed from an AF website in '97, and that particular site disappeared in '99 (going by the internet archive).
SMOKEY44211 (Automotive)
7 Jun 06 1:56
There never was an analytical test done to prove that R12 caused depleation of the ozone layer. There was a fellow who owned an automotive a/c repair facility near Cape Kennedy in Florida that was able to convince NASA to gather and analize samples of atmosphere at different altitudes. (This was done prior to the ban on R12). The results were that while trace amounts of R12 were found at the altitude of the ozone layer the concentration was too low to have any measurable effect. If memory serves me correctly it was a former presidential candidate that sponsored the bill to ban R12.-------Phil
MacGyverS2000 (Electrical)
7 Jun 06 8:39
Not buying that report, either...

Dan - Owner
http://www.Hi-TecDesigns.com

GregLocock (Automotive)
7 Jun 06 9:27
Hmm, that  PDF's either a convincing fake or it is interesting. So, if you used R12 in the same circumstances what would happen?

And given that most people who use R134a use a containment system when exhusting it, should we care?

After all, we succesfully deal with far greater volumes of far more deadly gases on a regular basis.


Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

transmissiontowers (Structural)
8 Jun 06 22:44
If you inhale any gas in sufficient quantities, it will kill you.  A friend's brother (air conditioning repair man)committed suicide by opening a full R134 canister in his van.

_____________________________________
I have been called "A storehouse of worthless information" many times.

GregLocock (Automotive)
8 Jun 06 22:51
Silly question. Is R134a exactly the same as H134a?

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

Helpful Member!  ivymike (Mechanical)
8 Jun 06 22:57
PRODUCT NAME: Refrigerant 134a
CHEMICAL NAME: 1,1,1,2-Tetrafluoroethane
CHEMICAL FAMILY: Hydrogenated Fluorocarbon
FORMULA: F,CCH2F
SYNONYMS: Fluorocarbon-134a, H134a, HFC 134a, HFA 134a, 134a, R134a
pennpoint (Mechanical)
10 Jul 06 3:27
Thank you

Best regards
pennpoint

quark (Mechanical)
13 Jul 06 6:31
The difference in performance between R12 and R134a is not very significant.

Page no.2 in the link below gives you a comparison of R12 and R134a. Page no. 18 gives you inhalation toxicity.

http://www.dupont.com/suva/na/usa/aa/pdf/h45945.pdf

No living organism (or precisely cell) can't survive in a pure oxygen environment. Check the MSDS at,

http://www.uigi.com/MSDS_gaseous_O2.html#SECT11

berkshire (Aeronautics)
13 Jul 06 15:29
This link may relate to some of these issues.

http://refrigerants.dupont.com/Suva/en_US/pdf/macs_200502.pdf

B.E.
patprimmer (Publican)
13 Jul 06 19:16
A cynical view might go like this.

DuPont invents and patents Fluor carbon type refrigerant gasses. They have exceptional performance and DuPont makes a lot of money while establishing market dominance and manufacturing strength with extensive plant.

Patents expire, but previous investment in plant, manufacturing experience and market dominance still provides a good profit.

Others enter market and gradually improve and begin to undermine prices and take market share.

DuPont starts work on alternative, develops and patents some.

DuPont announces that it has discovered that Fluor carbon damages ozone layer and we will all be seriously damaged by increased exposure to UV light, but hey, just ban Fluor carbon. No worries about repercussions because we have safer alternatives (which just happen to be patented.

Anecdotal evidence, directly to me from industry insiders suggested that Fluor carbon does in fact damage the ozone layer and allow in extra UV light, but extra UV light converts more oxygen to ozone, and thus self heals, although at a somewhat lower level at equilibrium.

Regards

eng-tips, by professional engineers for professional engineers
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evelrod (Automotive)
13 Jul 06 21:40
Hi Pat.  Thanks.  At least I don't need to make a redundant statement.

Cynical to the last,

Rod

PS:  FYI---The 91 Dodge diesel and the 85 BBC motorhome I converted to R 134 five or six years ago are still working just fine.  I see little or no difference in performance from when they were R 12.
patprimmer (Publican)
14 Jul 06 0:38
Hi Rod

I think we both have a reputation for calling it as we see it, even at our own peril.

Co-incidental, (or luckily) we most often have a similar opinion or view.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

stout1 (Mechanical)
14 Jul 06 8:36
I may be a little behind with my info but I heard last week that since the 134 patent is running out that there is going to be a new one coming around soon.  Also this system is going to have a much higher operating pressure than the current systems so we won't be able to run the old vehicles on the new stuff.  My info is pretty vague and I have nothing to back it up but maybe someone else can, I'd be interested in knowing where things are going to headed in the future.

Michael
swall (Materials)
14 Jul 06 11:13
The SAE "Interior Climate Control Systems" committee is actively investigating alternative to R134a, which has been found to be a "greenhouse gas". One of the candidates is high pressure CO2.
Comcokid (Electrical)
14 Jul 06 11:27
I've heard that there is some investigation (in Europe, I think) of using CO2 as a refrigerant. Nontoxic and nonflammable. CO2 is a greenhouse gas, but using in auto AC would temporarily sequester some of the gas in cars. Presently, excess CO2 from industrial processes is released to the atmosphere.
GregLocock (Automotive)
14 Jul 06 21:02
meanwhile, to continue the (accurate IMO) conspiracy theory, gaseous hydrocarbons make perfectly good refrigerants and are compatible with current technology.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

SMOKEY44211 (Automotive)
15 Jul 06 1:14
I read in several books that the invention or formulation of what has become known as R-12 was credited to Thomas Midgley (same fellow that is credited for the developement of tetraethyl lead that was used in gasoline). He worked along with Charles Kettering at DELCO labs which was under the GM coorperate umbrella. There was a large financial interest in GM held by Dupont. As a result of his work household refrigerators became common. It amazes me that some little birdie can whisper in a politicians ear "the sky is falling" next thing you know product is banned throughout the world. Conspiracy? More then likely. What to do about it? I'm open to suggestion.------Phil
Comcokid (Electrical)
15 Jul 06 15:17
R134a from a cooling and reilability standpoint doesn't seem too bad. The problem is the PAG lubercant used with it. It is extremely hydroscopic and breaks down becomming corrosive if it azorbs moisture. Sometimes repairs entail replacing EVERYTHING, compressor, condensor, evaporator, hoses, and all associated piping! I'm sure this makes Detroit, parts dealers, and repair shops happy, because the expense of repairing a bad out-of-warrenty AC makes cars more disposable. A more "Green" way to go would be to make cars last longer, but that doesn't create more pay for automotive CEO's. They make money only if used cars are crushed.

In the old R12/minerial oil systems, moisture intrusion really only meant you needed to replace the dryer, pull a vacuum on the system and refill. If a system was abused to the point of dessicant breakdown, little more than a dryer, compressor, and system flush might be needed.
swall (Materials)
15 Jul 06 17:38
In my experience, PAG is not that hydroscopic. Certainly not as bad as glycol ether brake fluids. We used to call PAG "goose grease", since it was hard to wash it off your hands.
pennpoint (Mechanical)
18 Jul 06 23:21
Swall,
Simple alcohol, works really good for clean-up as many brake shops found out long ago.
To the point: We all are beyond R-12, R-22 and have  replacements for both now, stop lamenting and move on, your best bet is to provide the best service to your customers now and in the future for brakes...same goes for AC...


Best regards
pennpoint
rmw (Mechanical)
22 Jul 06 18:39
The thermodynamics are that R-134 doesn't perform as well as R-12 in the older R-12 systems because the systems were designed with respect to the surface areas of the evaporator and condenser for the thermodynamic characteristics of R-12.  In systems designed for specifically for R-134 with larger surface areas, the systems work just fine.

With most of the older R-12 systems gone, converting and oil compatibility issues are way in the past (except for some of the old vehicles sitting in my driveway that still use R-12 but I squirrled away enough to outlast them, I hope).

rmw

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