R-12 refrigerant alternative discussion

[RickM]

Borrowed from a Mercedes forum. I don't recall reading about R406A. Comments on the conclusion are welcome.....



Quoted from http://www.mercedesshop.com/shopforum/showthread.php?t=157297

"Excellent Thread on Alternative Refrigerants"

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" http://groups.google.com/group/rec.a...706bf8554d444b

The whole thing is very interesting, but in particular skip down towards the bottom and note this logic:


Quote:
R-134a has a couple of problems, when used in a system designed for R-12.

Firstly, the boiling point of R-134a is about -15F compared to R-12 at -21.6F. (at one Atmosphere).. This causes 4 or 5 degree warmer duct temperatures unless the system is modified by setting low pressure cutout lower to compensate. Variable displacement compressors, such at the GM V5 are difficult or impossible to modify, and always set the suction pressure at 28 PSIG.

R-134a has a lower "critical" temperature (214F) vs 233F for R-12. The critical temperature of a gas is the the temperature at which as gas will no longer condense to a liquid, no matter how much pressure is placed upon it.

When under the hood/condenser temperatures approach the critical temperature of a refrigerant, head pressures soar, and cooling performance goes down the tubes. Under the hood temps of 220F are not uncommon.

Other manufacturers market blends comprised primarily of R-134a and are "cut" with either R-142b or R-124, both of which have higher (warmer) boiling points than R-134a.

R-12 boiling point -21.6
R-134a boiling pt -15
R-124 boiling pt +10
R-142b boiling pt +14

So, how is adding 20% - 40% of R-124 or R-142b going to make the refrigerant any colder than R-134a is already without having a "balancing" ingredient in the colder direction?

R-406A contains 55% R-22, and R-414A contains 51% R-22 to produce a correct temperature-pressure relationship which closely tracks R-12 and doesn't require changing the oil nor the pressure controls. R-22 boils at -44F."

[unclebilly]

In some places you can buy R12a which is a mixture of propane and butane. I run it in my pickup and have used it in my old Jag V12. My brother recently used it to top up the 134a in my old 944 with excellent results.

[IaAaron]

I just had a customer come in and requested HC-12a I guess it is like R12 but is more effective and environment friendly. It also only takes 35% of the r12 capacity! And it costs like 6.50 a can!!

[SlantnoseSD]

I just did a Google search for HC-12a and it says it is a viable alternative to R-12.

Will it damage and R-12 system?

[IaAaron]

Not according to the papers I have here. It says that it is a safe alternative and that it requires no retrofitting or special tools other than the ones already needed to recharge the r12. the best thing is i believe that you can buy it as an individual not just as a certified A/C guy.

the info I have was at Foxtoolsupply.com

[rfuerst911sc]

I am running the HC12A from Fox Tool and have been for about a year now with no issues. I replaced all my lines with barrier when I did my upgrade. The only downside I see to useing this is it's flammable and if your the type of person that has a shop do your AC work most don't want to work with any of the refrigerant "cocktails" for fear of contaminating their equipment.

[SlantnoseSD]

Where can you buy the HC12A?

[vesnyder]

I used this stuff hesitantly over two years ago thinking that I would hav to redo teh entire system at some point and it is still running cold to this day - well worth the price! And these guys were very helpful.

[IaAaron]

there are a couple of diffrent places. If you want more info please Email me.

Aaron@imagineauto.com

[SlantnoseSD]

Just found a shop in San Diego that will charge my system with HC12a for about $159 and they offer a $40 coupon on the internet.

Pm me if anyone wants the info.

[IaAaron]

That is a pretty darn good price! Glad there are people using this!

[schamp]

Is this the same stuff as freeze 12?

[Barrpete]

No Freeze - 12 is a blend of 80% R-134a and 20% R-142b. R-12a is a blend of propane, butane and isobutane. You can get some info here: http://www.epa.gov/ozone/snap/refrigerants/macssubs.html
Here's a link to a study of different refrigerants, although they didn't test freeze - 12
http://www.ackits.com/testresults/alttest.pdf

[ruf-porsche]

I'll stick with R12. Good thing I invested in R12 when it was still available (wink, wink).

[cashflyer]

Other discussions on R-12 and replacements....

Thread from earlier this month:
R-414B as an alternative to R-12???

And this thread, started last summer:
Info for R12 users