The use of car air conditioning has been around for decades now, with many different types of systems being developed over time. One type that was popular early on was based on the R-12 (or freon) system.
This came about because R-11 or carbon dioxide wasn’t considered safe enough due to its high flammability. However, there were other problems with R-11 and health hazard concerns.
As such, engineers created an alternative called R-12, which became known as “freon.” But despite this name, “freon” isn’t actually part of the chemical formula for the substance itself. Regardless, R-12 is still commonly referred to as “refrigerator oil,” but that doesn’t make any sense either.
But let’s get back to what we’re talking about here. If you’ve ever seen your mechanic open up a regular household refrigerator, then you probably know what R-12 looks like. Car manufacturers have long since replaced R-12 with newer alternatives, most notably R-134a. So, why did they do this? And how was R-134a better than R-12 anyway? And what led to the most recent shift to 1234yf?
So first things first, what exactly is this new substance that car manufacturers have switched to? Just so we’re clear, 134-a is out, and 1234yf is in.
Both of them contain fluorocarbons, though, which have a pretty technical meaning. Fluorocarbon means that it contains hydrogen atoms bonded to three oxygen atoms instead of just one. They act as solvents within the cooling cycle of cars’ air conditioners.
However, the issue with 134a was not direct human health hazards (although it is harmful if ingested directly), but more with our ozone layer and the health of the Earth. But we’ll get into that later. First, let’s give you a little background on car air conditioning.
Well, before R-134a took over completely, the R-12 system worked well. It utilized a closed-loop process where evaporated refrigerant would go through heat absorption and condensation. This allowed it to produce cold temperatures, but it had significant hazards to humans and the environment.
This method uses a compressor, condenser, expansion valve, liquid receiver, and evaporator. Once compressed, the refrigerant goes to the condenser via tubing.
Here, it transfers all of its energy to outside air passing across it. Then, the air flows past the fins of the condenser until it reaches the expansion valve. From there, the vaporized molecules pass onto the evaporator, where they absorb thermal energy again. Finally, the refrigerant returns to the compressor, where it repeats the whole process.
However, with the introduction of R-134a, the traditional way of doing things changed slightly. Instead of going straight to the compression stage, it went directly to the condenser. Afterward, the air passes through the same path as above, only bypassing the evaporation section entirely. According to the U.S. Department of Energy’s research, a significant amount of power consumption is lost during this step.
Basically, the modern R-134a system relies on direct contact heat exchangers to transfer all of its energy to the outside world rather than relying solely on the pressure generated by compressors.
Before R-134a got introduced, R-12 was widely used throughout homes, businesses, and vehicles worldwide. However, this didn’t come without consequences.
For starters, R-12 is extremely toxic to humans. Even small amounts can cause damage to your eyes, lungs, kidneys, liver, heart, blood vessels, and nervous system.
It can also lead to cancer, birth defects, and death in extreme cases. Because of this, it is classified as hazardous waste material.
Not only that, but R-12 causes global warming by destroying Earth’s protective ozone layer. Ozone protects us against harmful ultraviolet rays. Without it, plants wouldn’t grow properly, causing major agricultural issues.
In addition, R-12 contributes heavily to smog formation, water contamination, land degradation, deforestation, species extinction, and oceanic dead zones. All of these negative environmental effects led scientists to develop ways to replace R-12 with environmentally-friendly materials.
After further investigation showed that R-134a is not carcinogenic or mutagenic, researchers gradually began developing methods to switch companies over to it. By 2006, almost every single state in America had passed laws requiring automakers to begin making changes. A year later, the EPA set limits on emissions, and by 2009, R-134a was deemed suitable for general public usage.
At present day, R-134a is used primarily by commercial buildings and WAS used in the auto industry. Meanwhile, car owners can still find it installed in automobiles manufactured starting from 1995 onwards.
Unfortunately, the widespread adoption of R-134a hasn’t solved everything yet. Its biggest downside is that it depletes the ozone layer even faster than R-12 does, meaning that it can’t be used in cars.
For this reason, scientists and environmentalists started looking towards creating substitutes. Fortunately, a few years ago, they found a solution in the form of R-1234yf.
Unlike R-134a, R-1234yf works similarly to R-12 but requires lower pressures to achieve optimal efficiency levels. Due to this, it takes up approximately 34% less space inside vehicle systems than R-12 does.
Also, R-1234yf is able to withstand higher operating temperatures. Because of these differences, it needs far smaller quantities of electricity to operate effectively.
Furthermore, it releases significantly fewer greenhouse gasses compared to R-12 and R-134a. Lastly, it won’t harm human health (unless ingested directly) or the environment as R-12 does.
Overall, R-1234yf offers numerous benefits compared to R-134a. Considering that it’s already used in new vehicles, car owners should consider switching to it next time their systems need to be recharged instead of R-134a (although R-134a will still be available until the demand completely dies out and no vehicles are left that use it).
The name of this particular brand of coolant refers to its chemical formula, which includes two parts: one part contains three fluorine atoms, and another one consists of four hydrogen atoms.
In order to be clear here, let’s compare it to water. Water is made out of hydrogen and oxygen molecules. When talking about this specific kind of material, the same composition applies except that instead of just adding hydrogens, it adds fluorine, too.
These fluorinated hydrocarbon compounds are known as “halogenated alkanes” or fluoro olefins. Scientists believe that these substances should work well both inside car engines and in car air conditioning units. On top of that, since they contain fewer additives, they’re not nearly as hard on the environment.
Air conditioners that are filled with 1234yf are almost exactly the same as those using 134a. However, there are a few differences that should be highlighted.
First, an extra component in the process is an inline heat exchanger containing two concentric chambers. The liquid material from the condenser runs through the internal chamber, while the external chamber encompasses it with vapors. These vapors are produced from the evaporator as the liquid begins to return to the compressor.
While the vapor is still cold, it sucks the heat from the liquid coolant, which drops it to “sub-cooling” levels which are lower than condensation temperature. This improves the overall efficiency of the entire system.
Two basic types of inline heat exchangers exist. When an air conditioner has an orifice tube, the IHX is normally incorporated into the accumulator.
When it comes to expansion valve air conditioning systems, the IHX is more often than not an independent part. It exists as a tube inside another tube with inlet and outlet ports on either end.
This means there are no moving parts, so there’s no need to worry about any wear or replacement. Unless, of course, there’s external damage done from another source.
Another big difference between the two systems entails updated service ports and caps. Service ports are crafted to make it impossible to connect equipment that’s designed for systems that use other types of refrigerants.
However, adapters are always available as a backdoor method, and most shops can produce a reason to use these adapters. Service ports have been pointed out as a primary source of leaking and contamination in the air.
When vehicles sit long enough with the cold air conditioner turned on, the refrigerant will return to a liquid state. The pressure can drop below the pressure in the atmosphere.
When this happens, pressure can cause the service port valve to move, allowing air into the system. This air contaminates the entire setup – but there’s a solution to this problem.
Typically this won’t happen in areas of high temperatures and humidity. In areas where it gets cooler, and the air is drier, it happens pretty frequently. New service port caps were designed to have an O-ring that seals the port’s cap opening.
The O-ring doesn’t just keep air from contaminating the system. It also does the following:
New AC systems are also designed with completely remodeled evaporators that are more durable and have fewer chances of leaking. This doesn’t mean that you don’t have to check for leaks because it’s not bulletproof, and cases of leakage are still possible.
If you end up having to replace the evaporator, you need to check the code, package, or part number and ensure that it meets the new SAE J2842 standard.
Let’s examine some of the pros and cons associated with the changeover to 1234yf.
As stated earlier, one major plus of using 1234yf is that it produces fewer emissions than previous types of fluids. Due to its ability to dissolve moisture, it prevents mold growth, which improves the lifespan of your air conditioner and keeps your cabin nice and dry.
On top of that, there are actually lots of additional perks associated with this chemical. First off, it allows users to operate their car’s cooling system efficiently without experiencing any adverse effects. Some of the other benefits include:
Overall, 1234yf is a reliable choice for the auto industry, especially when it comes to lowering the carbon footprint of vehicle owners. It seems as if upgraded AC units have less of a chance to leak or become damaged, as well.
Unfortunately, despite all of these positives, there are still a few downsides associated with using 1234yf.
Despite these setbacks, we believe that 1234yf remains a solid option to stand in place of 134a.
All in all, 1234yf seems like an efficient choice when it comes to automotive air conditioning. It certainly is more efficient in terms of safety for humans and the environment than the previous offerings of R-12 and 134a.
One important thing to keep in mind is owning a vehicle that uses the older system (134a); this refrigerant will still be available for charging your air conditioner. If you own a new vehicle that emerged from the factory using 1234yf, you need to ensure anyone working on your vehicle is using the right coolant and not 134a.
Although there are new port openings to prevent this, adapters are available, and you still need to remain vigilant to protect your vehicle and equipment.