HVAC pros...why doesn't auto a/c use a natural refrigerant?

[txnoob]

There wasn't an auto a/c forum so this seemed the best choice.

I read an article the other week that really got my blood boiling. If I locate it again I'll post it, but the summary was that most of Europe is looking to phase out R-134a, not because it harms the ozone (which it doesn't) but now because they claim it still carries "global warming potential". In other words, I read this as the patent is about to expire, they need some new wonder refrigerant that is even more environmentally friendly so the manufacturers, DuPont I guess, can make some more money. This is the same stuff we went through with R-12. If Europe embraces this, it won't be long before the U.S. has to be politically correct too and we're in the same boat.

So my question is why can't, say, ammonia or carbon dioxide be used for auto a/c cooling? I admit I don't really know much about the two refrigerants except that ammonia attacks copper and I think carbon dioxide has to operate at much higher pressure than most commercial refrigerants.

I understand why some people don't want to switch over to either of those two...it's all about the money....but are there practical/technical reasons why either of those two could not work for auto a/c?

[mark beiser]

There is a strong push in Europe right now for automotive AC to use CO2 refrigerant. At least 2 companies have developed transcritical cycle automotive AC/heat pump systems that use CO2, and one of them claims to be ready to go with the technology right now.
The auto manufacturers want to use HFO refrigerants though.

[davefr]

I wish they'd bring back R-764. (best refrigerant ever)

[Andy Schoen]

The auto manufacturers want to use HFO refrigerants though.

HFO-1234yf looks to be a winner here.

[ammoniadog]

Co2 IS the global warming gas that environmentalists are trying to reduce from our atmosphere the most. It will soon be illegal too. Whatever you do, don't let them catch you breathing, or drinking some vintage soft drink that you got on the black market.

[amd]

heh

Now that the environmental movement has condemned inert, environmentally friendly (since zero ODP refrigerants have been developed), safe refrigerants, the industry has started looking at flammable hydrocarbons and toxic ammonia/sulfur dioxide again - the very substances CFCs/HFCs/HCFCs were developed to replace!

They won't be happy until refrigeration/AC gets banned and people succumb to food poisoning.

[craig1]

CO2 refrigeration systems operate at a VERY high pressure. The hoses and seals required to contain it are very expensive. Even the smallest leak will result in a quick loss of all the refrigerant. CO2 will most likely be the next refrigerant for automobile use


ammonia is not used because it is dangerous if inhaled. Since the A/C condenser is right behind the bumper, it is very likely that the refrigerant will be vented in a crash. For this reason ammonia will never be used in auto A/C

[oroy54]

I am on this ammonia 50 ton unit project. I asked why the corporate engineers decided on nh3. They said DuPont's CFC's were a pain in the the butt. To much goverment paper work.
Remember DuPont has a trade name on a lot of stuff. Nylon, Dacron, Teflon, Akron, Rayon and those balloons I forget. And last but not least Freon. All kinds of Freon.

I work in the Alathon division. My company bought the trade name and the polymers part of it.

And yes the patent has an expiration date.

Yep, It time for some new blood.

[oroy54]

CO2 refrigeration systems operate at a VERY high pressure. The hoses and seals required to contain it are very expensive. Even the smallest leak will result in a quick loss of all the refrigerant. CO2 will most likely be the next refrigerant for automobile use


ammonia is not used because it is dangerous if inhaled. Since the A/C condenser is right behind the bumper, it is very likely that the refrigerant will be vented in a crash. For this reason ammonia will never be used in auto A/C

No problem. That is why there are engineers. I can drive a small train. Its about time for a chat with Andy.

[beachtech]

ammonia is not used because it is dangerous if inhaled

the self alarming refrigerant

[txnoob]

Thanks for the feedback everyone.

CO2 refrigeration systems operate at a VERY high pressure. The hoses and seals required to contain it are very expensive. Even the smallest leak will result in a quick loss of all the refrigerant. CO2 will most likely be the next refrigerant for automobile use


ammonia is not used because it is dangerous if inhaled. Since the A/C condenser is right behind the bumper, it is very likely that the refrigerant will be vented in a crash. For this reason ammonia will never be used in auto A/C

As for carbon dioxide, I would not imagine the high pressure should be any problem. Brake lines have to withstand similar pressures but you don't see a lot of them springing a leak these days.

I know that ammonia can be toxic at certain stages, but how much would actually be considered toxic? For example, I think these days the average amount of 134a in an auto a/c is around 10-12 oz?? Maybe a little more? How much ammonia would be required for auto a/c?

On top of that, why is ammonia considered taboo for auto a/c? Because it's toxic? If that's the case, why is ammonia used for refrigerators powered by natural gas or propane? I understand the aspect of getting in a crash...but is there any other factor in ruling it out?

[mark beiser]

Co2 IS the global warming gas that environmentalists are trying to reduce from our atmosphere the most.

The amusing thing about the automotive AC debate in Europe it is that one of the primary arguments the environmentalists make for CO2 refrigerant is that it is an "environmentally neutral" natural and safe refrigerant.

Like, hey wait, haven't you guys been telling us that CO2 is a dangerous atmospheric pollutant that we have to control at all costs, even if it cripples our economies and standard of living?

[davefr]

Thanks for the feedback everyone.


I know that ammonia can be toxic at certain stages, but how much would actually be considered toxic? For example, I think these days the average amount of 134a in an auto a/c is around 10-12 oz?? Maybe a little more? How much ammonia would be required for auto a/c?

On top of that, why is ammonia considered taboo for auto a/c? Because it's toxic? If that's the case, why is ammonia used for refrigerators powered by natural gas or propane? I understand the aspect of getting in a crash...but is there any other factor in ruling it out?

In a crash I'd be more worried about 20 gallons of gasoline then 10-12 oz of ammonia.

[timebuilder]

In a crash I'd be more worried about 20 gallons of gasoline then 10-12 oz of ammonia.

...especially if your air conditioned car was a Pinto or a Crown Victoria.

[double bogey]

I would worry about the ammonia dumping out of the evap into the cab while driving 70mph. You couldn't get out of the car soon enough.