Using HFC-134A to directly cool intercooler core. Dangers? 1

[Baldturbofreak]

Who can tell me definitivly about potential dangers involved with HFC-134A seeping into the engine and being combusted?

The Intercooler I have constructed is made from a bar/plate liquid/air cores from garrett. It is inside the manifold plenum and used as a diffuser/flow straightener. It's isolated from engine heat Via a 1.5" phenolic plate between it and the Billet intake manifold below it.
I have tested the core to 200psi under water with no leaks present. But it also hasn't seen the vibration of a 2.0L @7500rpm burnin'50lbs/min.(MR-2 T)
If by some series of events a fissure opes up and allows refigerant to seep into the intake and it goes thru the motor will it make a poisinous gas?
I have heard horror stories about mechanics in the early days of EFI accidenatlly sticking the r-12 canister on the fuel rail and killing half the shop off with fozgene gas. I'm no chemical engineer so please anyone, is this urban legend or what?
Please keep discussion to the dangers of HFC-134A being combusted only.

 

[MechanicalChef]

I can't offer much help to the problem, but I have been near a vehicle that burst an AC line while the system was being charged w/ R134. The gas was subsequently sucked through the engine and combusted. The resultant fumes kicked out of the exhaust were nasty nasty stuff.

 

[Warpspeed]

LPG should work as Greg says, after all, we have all seen LPG gas bottles freeze on a humid day. The evaporator pressure should be o/k, but the condensing pressure might be fairly high.

The other thing to be careful of is the compressor oil. It needs to be compatible with LPG ??? The other thing is getting the compressor oil to return to the compressor, and not collect somewhere else in the system and allow the compressor to run dry.

I am sure it should work, it just needs a few details looking into. It would also make a very low cost refrigerant. Very interesting idea there Greg.

 

[GregLocock]

Well, it isn't my idea at all. When R12 was being banned various 'authorities' in Oz evaluated the alternatives.

Quite how LPG got rejected is a tale for the pub, some of the arguments were laughable (ZOMG hydrocarbons under the hood of a car! Oh the humanity), but either way there is a lively backyard trade in LPG regassing of automotive A/C systems. In fact the unstoppable Corona may just be heading that way.

http://en.wikipedia.org/wiki/Liquified_petroleum_gas#Refrigeration_and_air_conditioning

http://www.epa.gov/ozone/snap/refrigerants/hc-12a.html

etc


Cheers

Greg Locock

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

 

[Lou Scannon]

I thought the main objection to hydrocarbon refrigerants (i.e. for automobiles) was the potential consequences of a leak in the evaporator core.

 

[MikeHalloran]

Given the odorant in LPG, a core leak would not go unnoticed.

The >panic< was incited over the >presence< of ~2lb. of LPG in the vehicle... along with a coupla hunnert lb. of gasoline, not mentioned by the panic- mongers.



Mike Halloran
Pembroke Pines, FL, USA

 

[Warpspeed]

Ha-ha, if gasoline was not so useful, the EPA would have completely outlawed it's use long ago.

 

[Lou Scannon]

A spontaneous leak is one thing... a leak resulting from a crash, with potential ignition sources on hand, is another.
I fully agree, gasoline is grandfathered; but the deep pockets are very reluctant to add any new safety hazards.

 

[patprimmer]

The A/C condenser is in a very vulnerable position when compared to the fuel system.

Regards

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[Baldturbofreak]

One nice thing about it though is that it's gaseous. In the event of an accident it will dissapate into the atmosphere. Gasoline will make a nice puddle underyou and burn.
So long as the propane doesnt ignite inside the car like afuel bomb...

 

[patprimmer]

Because it's gas, it burns more readily. The point in favour is that it is only required in small quantities.

Regards

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[franzh]

Just to toss in my two cents:

Several years ago (in the early 70's) I attended a fire safety school for automobile technicians. We were told by a fire safety instructor that if we encounter an underhood fire to cut a refigerant line. The resultant spray of R-12 would extinguish the fire.

That same week, that instructor was demonstrating the fire extinguishing method by actually cutting a fully charged line on a car engine fire and was overcome by the fumes, was hospitalized, and subsequently placed on a respirator! From what I remember, he didnt make it very long afterwards.

Franz

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[Lou Scannon]

Youch!

 

[MikeHalloran]

A breached condenser will vent its contents to the atmosphere, well away from the cabin.

Said former firefighter probably heard that R-12 is not flammable. True, but the lube oil vapor that comes out of a breach with it, is.







Mike Halloran
Pembroke Pines, FL, USA