r290 conversion procedures

[standardmoose]

hello all ,
i was wondering if any one has done a conversion from a r12 or r22 standard window ac unit to a r290 or r290 r600 blend? if any of you have done, do you have the producers of how you have to do it, as im looking at trying it on one of my units?
cheers

[nike123]

There is no such procedure.

You cannot convert your r12 or r22 unit to R290 or r600 without changing compressor and expansion device.

[BradC]

I've done it on 2 Window A/C's, and used a 60/40 R290/R600a blend in my car.

Sucked out the R22 and charged it right up. Both window A/C units are Cap Tube, and I charged by superheat. No problems and they've been going strong for 18 months.

The car was weighed in, by calculating the relative density vs R12.

R290 is neat in that it tends to transport most oils well.

[Grizzly]

I've done it on 2 Window A/C's, and used a 60/40 R290/R600a blend in my car.

Sucked out the R22 and charged it right up. Both window A/C units are Cap Tube, and I charged by superheat. No problems and they've been going strong for 18 months.


The car was weighed in, by calculating the relative density vs R12.

R290 is neat in that it tends to transport most oils well.
Is the use of R600 in a car wise/
Given that their systems are not hermetic (they leak!) and R600 goes BANG.

Grizzly

[hyperion]

I seem to remember somewhere that I read, that it has been made illegal to install R600 or other hydrocarbons in car A/C because of the explosion risk factor. Perhaps it does not apply to Australia.

[BradC]

"Leak" is a relative term I guess. Looking at the upper and lower flammability limits in air, it'd have to be a *big* leak to be big enough to burn, let alone explode.

I always wonder why people worry about ~600g of HC in the A/C, when I carry 60L of Petrol and 80L of propane in the boot, both of which are piped as a liquid under the car and around the hot motor.

[chillerman2006]

I seem to remember somewhere that I read, that it has been made illegal to install R600 or other hydrocarbons in car A/C because of the explosion risk factor. Perhaps it does not apply to Australia.

Yeah thats Right mate

you dont need a massive quantity / *big* leak in the confined space of a car to get the air mix just right to explode

[sterl]

Interesting discussion.

RE: Confines of a car and Propane/ Isobutane potential for explosions: A deep investigation done in Australia with some test on actual cars....

http://www.fam-bjork.se/citroen/AC/external/icopt97.pdf

http://www.hydrocarbons21.com/files/papers/usage-risk-hydrocarbons-cars-australia-us.pdf

The second link looks at it statistically and analytically and concludes that the entire cloud from a wholesale R-290/ R600a leak for a car occupies less than 30 litres. The pressure generated by a preexisting propane stoichiometric cloud touched off with a spark is less than 1.6 Barg; so the 30 litre cloud makes a pretty decent local pressure that might pop a windshield but released underhood as consequence of an accident it would create less damage due to pressure than a radiator rupture. In most cases it would not even overcome the weight of the hood....

The larger concern as per the experiences of the state of Idaho is technicians not knowing how to deal with the flammable refrigerants prior to employing open flame devices for soldering etc. This is as much a training issue as anything else; and commercial inertia in the automotive industry. Germany has mandated domestic refrigerators charged with R-290 or R-290/600a blends since 1989 and the transport refrigeration industry has used both propane and blends for more than 10-years in the US and internationally. Volvo had an arrangement on their trucks that pumped cool glycol refrigerated by propane magnetically coupled to the engine; a double shell hermetic arrangement permitted them to manage the charge by dumping it to the engine should a leak develop; must have been some interesting developments if the engine was not running.



R-717 is a much more dangerous chemical and system charges of 30,000 Lbs are pretty common in the US.

[cold.man]

if the system has R12 why not use R134a and for the R22 use R407c obviously you would have to replace the oil and follow the retrofit procedures.
when charging it is usually 10% less than R12 or R22 equivelant charge.
i remember reading somwhere though you should expect upto an 8% performance loss whether this is true unsure.

[standardmoose]

hi brad
did you use a chart to work out how much 290 you had to use in the window a/c's ? also you havent heard anyone try it with a split type have you? as we are running some tests to see if they would work in high ambient temperature?
also you ever thought about using r-1270 ?
cheers
phill

[Armstrong]

There is no such procedure.

You cannot convert your r12 or r22 unit to R290 or r600 without changing compressor and expansion device.

I think someone hasn't actually tried this before.

9023
9024
9025

9026
Before/After Condenser

It performs almost like R22, but is tricky to charge on a system setup for R22. It runs a little colder so you need to make sure your around 63-70 PSI lowside and superheat is usually a bit lower too. No matter what I did it was around 5-10 degrees.

[Armstrong]

Oh you need that filter drier too, and put two in series if you can spare it. HD5 grill/torch propane has less requirements for moisture content and it could also contain 10% or less of butane (600a).

[sawtell]

To Brad and all the other R290/ R600 and blend experts, Hydrocarbons don't always obey the laws of physics when it comes to mixing with air to create an explosion. The density of the refrigerant is different from R12/R22 so the compressors pumping capacity is changed, the metering device ( capillary tube) is not designed for hydrocarbons and will not accurately meter refrigerant to the evaporator. Your unit will probably consume slightly more power and run a little longer to to the same job. The efficiencies picked up by the use of hydrocarbon refrigerant is offset by the power consumed. Having said that, hydrocarbons when used correctly are a very efficient refrigerant when used in systems designed for them.