I've heard about it too and is curious of how it works. Greg might have a heart attack with this type of treacherous discussion....

Here are some white papers about it.
http://www.sae.org/events/aars/presentations/2008/manhoekim.pdf

http://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1162&context=iracc



Here are backyard youtube videos of folks installing it in their cars.

https://www.youtube.com/watch?v=3wkBnhcyO3Y

https://www.youtube.com/watch?v=i4uAXDyICsA

https://www.youtube.com/watch?v=dl4qOySVru0

https://www.youtube.com/watch?v=xmQRB64CHKA


.

Demothen, REALLY ?
That is the biggest bunch of double speak and non information I have ever seen posted here.
I challenge you to use actual nouns and specific procedures or take down your post.
It violates all the AC industry accepted physics knowledge base and the information in the MB FSM.

Woah. First off, I specifically said DONT TRY THIS. It's an interesting aside. That's all.
Second, why are you getting upset, exactly? Did I specifically insult you in any way, shape, or form?
Third, Types of Desiccants, Desiccant Breathers, Desiccant Air Breather Filters, Desiccant Types - Drytech Inc.
Did I ever specifically indicate that I was an expert on this? Did I question your knowledge? I just mentioned that there are some ways to dry desiccant. I pointed out that it's not something I would recommend, and specifically advised against doing so.

So you admit you just wanted to post something to the thread. Not anything useful and lots of junk ' science' and ' belief ' .... This thread is about inside the AC system of a MB. The silica beads in the receiver are below oil. All the evidence is that even just moisture under oil can not be extracted by vacuum in our cars and certainly not from silica under oil .

Yikes. Okay look, i posted that you can dry some dessicant. I was not aware that the receiver was entirely full to above the dessicant pack, however that is completely irrelivant as i did not say "oh, do this, it will work!" In fact, this may come as a surprise, but I agree with you! In fact, I am currently in the process of following your procedures on my own car! (As far as my budget will allow). Now can we please drop this? Actually, we are dropping this, I will simply avoid posting in as many of your threads as possible.
Congrats, you win.

Vstech and I ( and others ) have worked for years to keep out the junk science, the posters with vested interests ( sellers of Duracool , etc ) and the tendency of people to believe that a short cut exists to long term proper working of the AC system. The inside of the AC is a very harsh environment. Moisture removal is not just a ' nice thing to have happen' ... it makes a difference because it mixes with the oil and the refrigerant to form ACID.. which will eat little flakes off the inside of your metal AC parts... which can easily clog stuff including the TXvalve...
You can claim it is ME that is the problem... but everyone knows I try to keep enough warnings in these AC threads so that a normal person will know they need to go and do more research before spending potentially big money and labor ... which might have to be repeated... if they do not know and follow the physics of the situation.... at the very least they can supervise whomever is working on their ac and know when they are trying to take shortcuts... as most shops WILL... since their warranty seldom lasts more than a year or two... a properly refurbished AC system has the potential to work for 6-8 years with only small top off of the refrigerant... ( due to the intentional leak designed into the compressor shaft seal to keep it lubed )...
And to that last point... IF you use a BLEND... you can not JUST TOP OFF when it gets low because the different size molecules escape at a different rate... thus the ratio of blended refrigerants in the system changes due to the leak.
That is not the case with R134a OR R12...
and people need to know that it is pretty hard to find a shop with will deal with anything other than those two refrigerants... because they can not chance contaminating their recovery machines...

Thats a lot of money for a bit of propane.
Thats an understatement but I would love to see someone to it.
You don't need to attack him. I found his post very interesting and I'm glad he posted it.

I am attaching what he has posted.... he is clearly a smart guy since he is going to follow what Vstech and I have posted for ' the rules'... which comes from standard automotive AC industry standards AND the MB FSM...

Um... ES12A is quite a bit more than propane... its a blend of propane, butane and other chemicals...
Propane would not work as an automotive refrigerant...

Half of the $28 is shipping.

I spoke to Enviro Safe's technician. It is no longer called ES 12a and is now called "R134a Replacement Refrigerant with Dye" There's a 5 oz and a 6 oz size which is $4.40 and $4.95 ea. respectively. R134a Replacement Refrigerant with Dye Can Equivalent to 16 oz 134a Details and Online Ordering at Enviro-Safe, Inc

Research for yourselves, but I understand the biggest concern w/ moisture in an R-134A system is that water reacts w/ PAG oil to form acids that can quickly corrode an aluminum condenser or evaporator. But, I suggest Hella's PAO 68 oil for all refrigerants, since more efficient and doesn't absorb moisture significantly. Duracool sells it as "Oil Chill" or such, or buy on ebay. In an R-12 or HC refrigerant system w/ mineral oil (or PAO in mine), I think the main concern with moisture is getting enough water that it can freeze to clog the tubes. I agree that in Central CA in the summer, a few days open in no concern. But, if your filter/drier is old, smart to change regardless since I have heard the dessicant packs can degrade and send it thru the tubing.

I understand HC refrigerant is common now in Canadian cars. R-134A is outlawed in many countries, and soon to be in the U.S., since a potent "climate change" greenhouse gas. Millions of cars have used HC refrigerant for decades and the only fire I have read of is an AC guy in Australia who orchestrated a fire to prove a point. I poured some excess Duracool on the ground and lit it just for fun. No flash, it just burned slowly as a candle. It can only burn as fast as it vaporizes and the liquid is quite cold. I would fear carrying a newspaper in the car more. I have used Duracool in 4 of my vehicles, starting in 2002. I think they came before Envirosafe and seem more established.

BTW, ignore my advice to use your 300D vacuum pump, since 20 "Hg isn't sufficient to boil off water unless you get as hot as Sacramento. I used it before as a roughing pump, then finished off w/ a Mighty-Mite hand pump to 29.5 "Hg, but recently bought the Harbor Freight electric pump on sale ($40?), the downside being I lost my Popeye forearms (joke leathermag & VS Tech, I have only fixed AC a few times).

There are several problems with your post...but I am only going to address one.

The experiment you conducted was not anywhere near what would be the situation in real life.

I am just going to address the breach of the condensor.. since it is at the VERY FRONT of the car with no protection in a crash.... it is filled with a combination of hot refrigerant vapor under pressure at the top... with OIL mixed with it.... and at the bottom with hot liquid refrigerant under pressure with oil mixed with it....
So with Duracool you are basically working with propane mixed with oil and under pressure... so any break in the condensor produces a mist of hot propane mixed with oil ... with the probability of sparks.....

It would be different if the condensor was in the trunk...like the mid 1950's Buick.

You can see from this url.. that hydrocarbons are approved for NON MOBILE uses... refrigerators, etc...
They are restricted from mobile applications for safety purposes...

EPA Opens U.S. Market for Climate-Friendly Refrigerants - EIA

You forgot to mention that right behind the condenser is an even larger and more fragile container filled with water and steam under pressure just waiting to quench that massive 6oz propane fire.

Haha, I LOL'ed at that one.

I also drive gasoline cars...with high pressure fuel lines. I'll take a quick flash off of 12.8 oz of propane over 10gal of gasoline...

REALLY ?????

ANY of those lines IN FRONT OF THE RADIATOR ?