Interesting article. HFCs includes R134a. I couldn't find what they plan on replacing it with. Maybe propane?

NPR: U.S. will phase down HFCs, polluting compound found in ACs and refrigerators.
https://www.npr.org/2022/09/20/11234...bons-banned-us

Jeff

 

R134a wasn't any good anyway. Won't be missed.

 

The world is moving toward refrigerants that use less energy and have lower global warming potential and don't harm the atmosphere. Over the next century Billions of people are expected to move out of poverty across the world and will soon be able to adopt refrigeration and air conditioning. The implications for the atmosphere are considerable. So a new generation of refrigerants are being developed and standards for handling of older flammable ones are being introduced. The general direction is towards flammable or mildly flammable hydrocarbon base refrigerants which are low cost and highly efficient and low GWP. The low flammability and low GWP refrigerants are VERY expensive and less efficient. They are expensive because they have a molecular double bond which lowers flammability but is very difficult to produce.

At one extreme you have propane. R-290. Low GWP of 3, high efficiency, but highly flammable. Used in systems with very low volumes of refrigerant like small personal refrigerators, residential refrigerators and small commercial refrigeration. The low volumes reduce the risk of explosion.

At the other extreme you have HFO refrigerants like R1234yf. Low / No flammability, low GWP of 4 but very expensive. New refrigerants like this will be used in transportation where flammability tolerance is low. The price to produce these is very high so they're not all that viable for small refrigeration where the cost of the refrigerant would double the price of the unit and decrease it's efficacy. In an Automobile the extra 400$ for R1234F will hardly be noticed considering the over all price of the vehicle.

CO2 based refrigerants systems are being developed but run at VERY high pressures (500 to 900PSI) but have no GWP becasue they can reuse CO2 already in the atmosphere, so net zero CO2 gain (GWP of 1) There are many other risks for CO2 system, like asphyxiations of people working in small places with a large system that can develop a leak. The high pressures of service lines can turn a tool drop against a line into an catastrophic line failure explosion.

There are many new refrigerant blends that are have mild flammability, low power consumption and acceptable (for now) GWP. These will be used in commercial / building / home refrigeration but with special tools and techniques to manage the flammability problem.

Basically some new refrigerants are far more dangerous to the individual in many cases but easier on the environment. The concern is people may die from flammability but so far the wide spread use of flammable refrigerants in developing countries have been mostly un-eventful.

For older cars R1234yf could be used but pressure are much higher (400PSI or so) and the cost for your yearly top off may exceed $300 or so and cooling performance will be poor because older systems are not designed for such high pressures. Not much of an option. This leaves blends that are flammable. Good luck!

 

Great write-up, Icsamerica. I understand the flamability issue for large commercial installations but never saw the logic for cars since you have high pressure gasoline just a few feet in front of you.

 

Wasn't ammonia used back in the day ?

 

It's why cars have a "firewall" and why no fuel lines are transported inside the passenger compartment. An R290 system (propane) that developed a cabin leak at the evaporator "Could" explode and harm the driver and their ability to control the car. That's a risk no auto manufacturer is willing to take at the moment.

The solution to this is to have NO propane lines in the passenger compartment and keep them under the car with a glycol based heat exchanger but this is complex and heavy and can take too long to get to a cooling point so expensive R1234yf it is for now.

 

Enviro-Safe 134a Replacement Refrigerant

Available now and cool better that OEM refrigerants (yes mostly propane/butane), but does not harm environment if escapes; deals with system moisture that OEM refrigerants can't tolerate.
Have successfully used on 84XJ6 for 3+ years
Rgds
David

 

Not only used on my Xj6 Jaguar, but that Ancient Chrysler which I mention quite often in here, which was also R12 OEM.

I have easily over 10 years experience with this stuff (Ooo! Closer to 20 years experience now that I think about it!). It's very easy to use (directions on every can), takes far less to charge the system, and because of that, pressures are lower, hardware and hoses last longer and it leaks less due to larger molecular structure. Said to be compatible with all known refrigerants and lubricants.
BONUS!

(';')

 

I thought that the sale of hydrocarbons as refrigerants had been banned more or less everywhere. The contents of the EnviroSafe bottle can still be sold so long as it's not described as a refrigerant.

 

There was an Ice Company in Chico, Ca. many years ago, some of the Olde Timers still remember it from their youth. I think some videos still exist somewhere but I can't find it atm.

It got water cold alright, and worked REALLY fast, but sealing it up was a BIG problem, they relate, and one could smell it all over town when they were making a batch.

The Ice House is now a shell, made into a restaurant some years ago, building empty for decades.
(';')

 

Do you need to evacuate the system to use this? My system currently runs on R134. Ian

 

I didn't. I took them at their word about compatibility. Works Just Fine! In fact, they say you're NOT supposed to put in an empty system.

Check the companies website for directions BEFORE you commit.
RTFM and all that.
(';")

 

Yes, all OEM refrigerants should be removed (evacuated) by A/C shop. ( keeps GRETA from having a meltdown). The evacuation will remove some oil as well as moisture. (if you have an A/C system leak, have A/C shop use their sniffers to find it before evacuating).
Minimum prep for new ES refrigerant would be to replace receiver/drier and do oil service with system not running. With ES they do not require or recommend pulling a vacuum.
Rgds
David

 

I would always charge new refrigerant into an evacuated system. First, I always evacuate the system and see if it holds vacuum, then I know I don't have any leaks. If it doesn't hold vacuum, then I fix the leak.

If there is any air in the system, you wan to remove that, as it's what is called an uncondensable - in other words it won't change state inside the AC system, so it takes up space that could otherwise be occupied by refrigerant; yet it doesn't contribute to cooling.

 

I too have used Enviro-Safe in several of my older Mercedes with great sucess. The larger molecular structure is nice in older systems originally designed for R12 as the propane/butane won't leach out through the wall of the hoses like the smaller molecular R134.

 

Googled GRETA and couldn't find what it is the acronym for. I assume something about the Government?

 

I believe Devid84XJ6 refers to Greta Thunberg:

 

Don't get me started on changing governmental refrigerant regulations. I still miss R12.

I've used Enviro-Safe also, and recently converted a '73 E-Type with an empty R-12 A/C system to Enviro-Safe R134a Replacement. First, I converted the service ports so I could use my R134a manifold gauge set. Then I located and resolved the leaks in the system.

Then I did some math to estimate the proper Enviro-Safe charge. When converting from R12 to R134a, we typically use 75% to 85% R134a compared to the original R12 charge weight. Then, figure 6 ounces of Enviro-Safe per 16 ounces of R134a. The 8 ounce cans of Enviro-Safe are claimed to be equivalent to 21 ounces of R134a. So this system that was originally charged with 40 to 48 ounces of R12 only required 15 ounces of Enviro-Safe to cool well. Does it cool as well as R12? Probably not. Does it cool well enough? Yes.

Be sure to follow the current instructions from Enviro-Safe. They have changed over time.

Enviro-Safe R134a Replacement is predominately Liquefied Petroleum Gas, so it is rated "Extremely Flammable." See the attached Material Safety Data Sheet.

Cheers,

Don

 

Rather than weight, I use vent temperatures as the guide to charge a system.

I start charging into an evacuated system with the cabin fans on high. The vent temps will start coming down as refrigerant is added and at some point start to plateau at a minimum. I add a bit more and when the temperatures don't change and the pressures on both low and high sides start going up, that is the point when the system is fully charged. I also spray a garden hose on the condenser to remove the heat and ensure that I have an accurate indicator of how well the system can work.

I've been using propane/butane refrigerants for about 20 years and they have worked well for me. As a rough guide, I find that I use about 1/3 of the weight of R12 that was originally specified. From a thermodynamic point of view, the HC's have a slightly higher heat capacity than R12.

 

In our climate, I find that I can't go by vent temperature alone. If I charge a system in moderate ambient temps, it's too easy to add just a little too much refrigerant. The low and high pressures will look fine, but on the first hot day, idling at a stop light, the pressures will rise and the high-pressure switch will disable the compressor clutch and make everyone in the vehicle unhappy. It's not uncommon for our ambient temperatures to vary as much as 20 degrees Fahrenheit over the course of two weeks.

Monitoring the weight of the refrigerant added with an accurate scale is the best way to avoid inadvertent over-charging. I monitor vent temperature also because some old systems do not respond well to a full factory-specification charge. You know you've passed the limit when the vent temps start rising again, even if you haven't added the maximum charge per the factory specs.

Cheers,

Don