Improving the AC system's efficiency

[EcoCivic]

Originally Posted by teoman

Natural?

Yes. Propane and butane are naturally occurring gases

[Ecky]

If I actually used my A/C here I'd consider it, but the average high temperature in summer is only around 80 degrees, and humidity isn't too bad.

[teoman]

Thanks for the clarification.
The word natural has unfortunately loat most of its meaning due to marketing BS.

[teoman]

I wonder if some of the lines can be coated with ceramic to reduce heat entry to the AC system.

[pete c]

Of course the AC techs don't want this being used. It is freely available. And I get a kick out o fpeople that talk about what will happen in a front end crash. Worst case, you will have a very short duration flash fire. And you are in the car....behind the FIREWALL.

I may try this on the cab AC of my 87 Toyota Sunrader RV.

And there is one more benefit not yet mentioned. Propane is a ginormous molecule. Much less prone to leaking at seals. And if it does leak very slowly, who gives a sheeet? It is dirt cheap.

[EcoCivic]

Originally Posted by teoman

I wonder if some of the lines can be coated with ceramic to reduce heat entry to the AC system.

Great idea! You could actually coat the low pressure lines (The large pipes that get cold with the AC on) in ceramic, and it would improve the efficiency of the system, at least a tiny bit. It will reduce pressures and temperatures inside the system the same way that reducing the fan speed will, meaning that more of the system's capacity can be used to cool the inside of the car.

What I did is I used pipe insulation from the hardware store to insulate the metal parts of the lines where possible, which seems to work pretty well. However, I didn't want to use something combustible (foam pipe insulation) on the part of the AC line that goes down to the compressor because it runs right past the exhaust header, so what I did instead is I cut an old heater hose down the center, put it over the pipe as well as I could, ziptied it in place, and wrapped the whole thing in electrical tape.

Not pretty and I'm sure it isn't as effective as thick foam pipe insulation, but I am sure it is at least somewhat effective since the heater hose is pretty thick rubber, but most importantly, it won't cause a fire. I am probably going to try to find a better solution though since the heater hose is ugly and it doesn't fit well around the bends.

[oldtamiyaphile]

The oil for r134a is flammable, and when combusted, basically creates mustard gas- which is deadly at a few PPM. r134a runs at higher pressures so it's more likely burst and spray out onto something hot.

My last purchased car came with propane, if you've got an old car it's basically your only choice.

Originally Posted by EcoCivic

I am probably going to try to find a better solution though since the heater hose is ugly and it doesn't fit well around the bends.

Exhaust wrap would work. You could even wrap that in thick aluminium heat shielding. Reflect the heat before it gets there.

[jeff5may]

Originally Posted by pete c

Of course the AC techs don't want this being used. It is freely available. And I get a kick out o fpeople that talk about what will happen in a front end crash. Worst case, you will have a very short duration flash fire. And you are in the car....behind the FIREWALL.

I may try this on the cab AC of my 87 Toyota Sunrader RV.

And there is one more benefit not yet mentioned. Propane is a ginormous molecule. Much less prone to leaking at seals. And if it does leak very slowly, who gives a sheeet? It is dirt cheap.

I believe the r12 / r134a substituters were using about 70 percent butane and 30 percent propane to achieve the same vapor pressure in the system. As usual, a txv works better than a fixed orifice, but is less tolerant of being undercharged.

[EcoCivic]

Originally Posted by jeff5may

I believe the r12 / r134a substituters were using about 70 percent butane and 30 percent propane to achieve the same vapor pressure in the system. As usual, a txv works better than a fixed orifice, but is less tolerant of being undercharged.

According to the MSDS sheets I have read, R12A (the drop in R12 substitute) as well as Envirosafe R134A replacement are made out of 60% propane and 40% butane.

[ratgreen]

My AC is currently empty. Leaking core. Once I've fixed it, I can just use R600a instead of R134a (which my car normally takes)?