Thread: LPG as Refrigerant

Not L PG but related.
Not much is heard about this stuff.
.http://www.hychill.com.au/pdf/201012...a-mr-final.pdf

We can buy it off the shelf but have to be told it is not to be used for auto aircon in Qld. It is approved in other states.

Hychill minus 30 is a mix of R600a (isobutane) and R290 (propane) so it's as close to LPG as you are going to get ?

It used to go by the name HR12 and was/is really popular with auto air blokes in NSW.

Well, well, well, yes I am still alive and kicking !!!!

LPG as a refrigerant - well not quite - but really splitting hairs here

There are certain hydrocarbon gases classified by international organisations - like ASHRAE, AIRAH, etc., to be refrigerants - all these hydrocarbons are issued a Registration number, just like the chemical counterparts R12, R22, R134a etc.,

Pure refrigerant grade Propane is R290
Pure refrigerant grade Iso Butane is R600a
Pure refrigerant grade Butane is R600 - not used much
Pure refrigerant grade Ethane is R170

To replace R12 and R134a - a blend of R290 and R600a is used , the ratio is approx 50/50 depending on who's you use.

You would use approximatelly 33% of the chemical refrigerant charge, so if the original R134a charge was 750 g - a hc blend - you would use 250 g +/-

HC refrigerants are far more efficient that chemical refrigerants for the following reasons

the whole cruxt of a refrigerant is the ability to absorb or reject heat - and this is measured in Kj/kg - typically R134a is approx 128 kj/kg, whereas the HC replacement would be approx 330 kj/kg - - far far better at absorbing/rejecting heat, plus

Because of this there are other benefits - you do not have to raise the temp (and thus the pressure) of HC's as high as chemical refrigerants to enable them to condense back into a liquid - and that reduces head pressure, and that reduces drain on engine power, fuel consumption - and stress on compressors, hoses and fittings

Next we can talk about 'critical temp' (CT) - this is the point at which regardless of how much air you pump through a condenser you will never condense the refrigerant

With 'good old' R12 the CT was in the region of 120 Deg C - giving you loads of space to condense

R134a is crap - with a CT of less than 90 Deg C - you may think thats still high, but imagine a hot day, stuck in traffic with the tarmac giving off heat, engine heat, the heat from the car in front of you, and all of a sudden the heats right up there - and you end up condensing maybe 20% of your refrigerant - with 80% of it going through the TX valve as hot gas = this equals very poor cooling.

With HC refrigerants - especially the ones formulated for automotive have a CT of over 130 Deg C

So thats why they work.

Safety - has to be considered - but for automotive use 250 - 400 gramms is well within safety limits - and you compair it with 60 ltrs of pertrol or LPG under/behind the back seat - no comparison

You go to the supermarket, buy household goods, spray cooking oil, hair spray, shaving foam, furniture polish, you throw that lot into the back seat of a are on a 35 degree day - how many of those explode ??? and with 3 to four cans of the stuff thats more than the ref in the ac system

As rick says - on commercial installations you must adhere to standards, safety devices, alarms - and common sense, something that was obviously lacking in NZ cold store

I will shut up now

Take care all

Ladas

Welcome back ladas

Noting Ladas' response above, is it feasible to regas my car with an HC refrigerant? It seems that it might make it a more efficient system.

(I forgot to ask Ladas when I was speaking to him tonight.)

Ron, As I stated earlier(post 14) I have done my sons car with it. I did some research before using it and they claim that it is better than R134. You do have to completely remove the old gas though and not mix them.

It is very hot where we live in summer and my son is very happy with his aircon.

Dave.

Sorry, I missed that post, Dave.

Hmm, it gets up to the low 40s here in summer so I wouldn't mind Japanese aircon efficiency.

Originally Posted by p38arover

Sorry, I missed that post, Dave.

Hmm, it gets up to the low 40s here in summer so I wouldn't mind Japanese aircon efficiency.

Yamaha XJR1300 and Suzuki V-Strom = Japanese aircon.

Dave.