Propane-charged A/C explodes

[snopes]

Comment: I heard a story a long time ago about a woman living in San Diego
who drove across the border to Tijuana to have her car's A/C serviced. She
was very pleased with the low cost and the remarkably efficient cooling
when she picked her car up. While waiting in line to cross the border back
into the US, the front of the car exploded. The Mexican shop had used
propane to recharge the A/C system, and the leak that caused the loss of
performance in the first place led to a combustible mixture filling the
engine compartment.

[jimmy101_again]

Ya get what you pay for.

Propane can, and has been used as a refrigerant. I kind of doubt that an AC system designed for a particular type of Freon would work with "remarkably efficient cooling" when charged with propane. It might work but I doubt it would work very well.

It would certainly be possible to have a leak cause an explosion but even that isn't all that likely. The combustion limits for propane in air is about 3% to 9% by volume. More than 9% or less than 3% propane in air won't ignite no matter what you do to it. The air in the engine compartment is generally being constantly displaced by the engine's cooling fan (especially if it was warm enough to need the AC). So it would take an amazing convergence of factors to get a combustable mixture and an ignition source.

I had an 88 Bronco II that had a combination of propane and butane used as a refrigerant. It worked extremely well, as in much colder than the newly banned (at the time) R12 freon. It was meant to be used for off-road farm equipment, and I had to sign a waiver releasing the company from litigation, but there was never a problem with it, and it didn't explode causing the front end to disappear. My ex wife took the vehicle when she moved out, and I know, since she works for the same company as my sister, that if something untoward had happened, I would have heard something. The reason it was used is that we didn't have to retrofit the AC system with new seals and such, work that would have cost over $800, to be able to use R134 refrigerant.

[robertplattbell]

When I read this, I was like 'Yea, right!'. I worked at Carrier for five years in the research lab and never heard of anyone using Propane as a refrigerant!

Truth is stranger than fiction. Who knew?

It is highly refined propane and sold under the trade name DURACOOL.

They claim it works well in R-22 systems and it is "environmentally friendly" as a refrigerant leak is no more harmful (to the environment) than a gas leak from your gas grill.

Their slogan is "our formula never changes" because the formula is PROPANE.

Theoretically, if a leak occurred in the system, it could ignite in the presence of a spark. But I suspect it would make a jet of flame from the source of the leak, not explode violently, unless it was contained in a closed space (car cabin) mixed with air.

They add a chemical to the propane for leak detection. So you'd smell the stuff before it became explosive (I hope).

I always learn something new on Snopes!

BTW, the Mexican angle makes sense. Many trucks in Mexico are converted to run on Propane (or were when I drove through there 10 years ago) and there were plenty of propane refill stations around the country. They must have a good supply of it.

Also, dangerous refrigerants have been used in the past - the most notorious of these was Ammonia.

SPEAKING OF URBAN LEGENDS, the story I heard (at Carrier and elsewhere) was that Ammonia was used in some indoor ice skating rinks in evaporative systems "back in the day" (like 1910) and when a skater punctured the refrigerant tubing under the ice with his skate, it filled the indoor rink with ammonia has, killing everyone inside.

I think the story has a lot of holes in it. Most systems using Ammonia have the chiller in a separate building, which then chills "brine" (usually an antifreeze mixture) which is then pumped through tubes under the ice. But it makes for a good story...

I dropped a 5-gallon carboy of 50% Ammonia solution once. That stuff is nasty!

[robertplattbell]

I searched online and debunked my own myth.

This book from 1895 discusses man-made ice rinks in England and France and mentions that brine is piped through the floor, not the ammonia.

Interesting that they use the room below the ice rink for cold storage. Very efficient, those Victorian Engineers!

Originally Posted by robertplattbell

I searched online and debunked my own myth.

This book from 1895 discusses man-made ice rinks in England and France and mentions that brine is piped through the floor, not the ammonia.

Interesting that they use the room below the ice rink for cold storage. Very efficient, those Victorian Engineers!

Most rinks still use ammonia or R22 (most are ammonia) with a brine or glycol system. I had to take a 5 day, $500 to learn how it all works....if you really want to know, I could bore you with it.

[robertplattbell]

Originally Posted by The Game

Most rinks still use ammonia or R22 (most are ammonia) with a brine or glycol system. I had to take a 5 day, $500 to learn how it all works....if you really want to know, I could bore you with it.

That's all right. Five years in the labs at Carrier Corp were enough to bore me for a lifetime...