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hydroflurocarbons (HFCs) vs. hydrocarbons (HCs) Posted by billherbst [Email]  (#2137) [Profile/Gallery]
(more from billherbst) on Mon, 18 Jul 2005 23:37:49
In Reply to: Recharge my air, John, Sun, 17 Jul 2005 17:04:53 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I own a '99 9-5 wagon that has a fine AC system in working order, thank heavens, but I previously owned a '91 9000 whose AC leaked like a sieve. As a result, I did a LOT of research on this, since I had to fill (recharge) the system every summer for seven years.
A little history on automotive air conditing might be in order here:
Up to the early 1990s, car AC systems used R-12, otherwise known as "freon." This nasty stuff, a hydroflurocarbon (HFC), damaged the ozone layer AND contributed to global warming in a major way.
In 1992-93, manufacturers switched over to R-134a, a somewhat less-damaging but still toxic HFC that does not damage the ozone but DOES contribute to global warming.
Back then, Congress (through the Environmental Protection Agency or EPA for short) COULD have approved the use of hydrocarbons, which are essentially a 60/40 or 50/50 mixture of propane and butane (think lighter fluid), but because of the good-ole'-boy, fat-cat, megacorporate lobbying efforts of Dupont, these ideal refrigerants were passed over in favor of R-134a, which Dupont had a patent on, and a monopoly, of course. Dupont's lobbyists claimed that hydrocarbons were dangerous under pressure and could explode during accidents (which has literally never happened even once). Naturally, Congress went with the lies and Big Money (in the form of campaign contributions and other sleazy perks).
Hydrocarbons in auto AC systems are safe, extremely efficient (the molecules are three times bigger than those of R-134a, so they don't leak out as easily), and cause NO harm to the atmosphere--neither damaging the ozone layer nor contributing to global warming. They're so efficient that only 1/3 the amount of 134a is needed for a typical AC system. And they're dirt cheap--two 6-ounce cans (about $12 total) are sufficient to recharge your Saab and make the AC significantly colder than with R-134a.
Hydrocarbons are used extensively for auto AC systems in Europe and Canada and have been approved by Greenpeace. Google "hydrocarbon auto refrigerants" to find all the manufacturers, brands, and papers that have been written.
Unfortunately, because of Dupont, we in America have a hard time using them. Why? Because it's illegal here to release any HFCs (such as R-134a) into the atmosphere. Of course, millions of cars are leaking HFCs every day, so that's not illegal, but we can't intentionally release any coolant into the atmosphere (during a clean-out of the system, for instance).
So, thanks to the infinite wisdom of our government, every auto repair shop in America had to purchase a $5,000 machine to extract and bottle whatever they suck out of your leaking AC system BEFORE recharging it. And while HCs work beautifully with any auto AC system and can be used to top off both R-12 or R-134a systems, the EPA (in its infinite wisdom) has outlawed the practice of mixing coolants.
R-12 is effectively dead. In fact, it's illegal to even purchase R-12 without a special license, and because it's no longer made, the dwindling supplies are now unbelievably expensive. R-134a is much cheaper, but it's still a good deal more expensive than hydrocarbon refrigerants, and Dupont will keep jacking up the price over time.
So, what to do for a Saab 9-5 AC system that is basically still good but leaks and doesn't cool well?
1. Go to a repair shop. They'll diagnose and either top off or completely recharge your R-134a system. Cost: $100 and up to the statosphere, depending on diagnosis, leaks, new receiver-drier or other parts. For instance, a new compressor for a 9-5 costs about $700, with rebuilt units going for about $400. A new condenser costs $500. Yikes!
2. If you're a do-it-yourself guy and your AC system is leaking but still sound mechanically, you can buy a kit to recharge your system with R-134a, ester oil, and perhaps a small can of stop-leak. Put your car in the garage and close the door before discharging/recharging (away from the prying eyes of the EPA Big Brother brain-police). Cost: $50-80, assuming no nightmares, such as major parts replacement.
3. Switch to hydrocarbons. Some repair shops in the U.S. are now set up for this; most aren't. You can order a kit online to recharge your system with HCs (hydrocarbons), oil, and stop-leak for $40-$60. Worked great for me in my old 9000. Once I had the hoses and adapters, it was about $12 each summer thereafter. You'll get MUCH colder AC at a significantly cheaper cost without harming the environment. Same caveats apply as above, however, concerning defunct major parts.
One word of caution--keep in mind that AC systems are simple in principle, but complex in use and repair. Getting the right proportion of coolant and oil is important. Too little or too much coolant kills the efficiency and means lousy cooling. Gauges and procedures can be confusing. High-pressure side, low-pressure side, bad compressors, Aaarrgh!
On second thought, ignore everything I've written. Just take your 9-5 to a good mechanic or repair shop and get it fixed. LOL :)
posted by 71.37.2...
, Mon, 18 Jul 2005 23:37:49 <-- Viewing This Message
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