What is Freon Used For?
Freon, commonly known as R-22 is hydrochlorofluorocarbon (HCFC) used as refrigerant/coolant in air conditioners, refrigerators, dehumidifiers, transportation and cold storage units. It evaporates quickly, allowing it to absorb and remove heat from the surrounding air.
Although the words Freon and refrigerant are used interchangeably, they are not exactly the same thing. Freon is just one type of a refrigerant whereas there are many types of refrigerants with different chemical and physical properties.
The reason Freon has been used as a refrigerant for so long is its low boiling point. Compared to fluids like water which has a boiling point of 212 degrees Fahrenheit, Freon has a boiling point of about 40 degrees.
This means that Freon changes from its liquid state to its gaseous state easily, in a process known as evaporation. As the Freon evaporates, it absorbs and takes with it heat from the surrounding air.
It is very much like when we sweat. As the sweat evaporates from our skin, a cooling sensation is created which keeps our bodies cool. Another example is when dogs stick their tongues out when it is too hot.
Although Freon is an excellent refrigerant, its use and production is harmful to the environment. When released to the environment, Freon contributes to the depletion of the ozone layer which ultimately results in global warming.
January 1st 2020 was the last date for the production and importation of Freon in the US. Although Freon is still in use today, cooling systems still running on Freon as refrigerant are serviced using recycled Freon.
Refilling/recharging of Freon in your air conditioning unit should only be done by a licensed technician who are trained to handle and dispose the existing refrigerant. Doing so on your own is dangerous and can harm the environment.
History of Freon
Before Freon was used as a refrigerant/coolant, old air conditioning systems used other refrigerants like ammonia. However, ammonia as it turned out was a hazardous gas and also corroded copper pipes despite its good refrigeration properties.
In the 1920s, General Motors put together a research team lead by Charles Franklin Kettering and Thomas Midgley, Jr. to find a better alternative to the dangerous refrigerants at the time like ammonia.
The team improved the synthesis of chlorofluorocarbons (CFCs) and around 1928, they found that they (the CFCs) were stable, non-toxic and had excellent refrigeration properties.
A refrigerating apparatus patent was issued to Frigidaire, a subsidiary of General Motors. Later in 1930, Kinetic Chemicals was formed by General Motors and DuPont to commercially produce Freon.
By 1938, 8 million new air conditioners had been sold in United States using Freon made by Kinetic Chemicals. Carrier Engineering Corporation made the first self-contained air conditioning “The Atmospheric Cabinet” unit in 1932.
Unknown to most people, the name Freon is a registered trademark belonging to DuPont (E.I. du Pont de Nemours & Company).
How Freon Works in an Air Conditioning System
There are lots of homeowners who don’t have a clue of how their air conditioners work. If you are in that category, this article here will help.
If you have a central air conditioner or even a ductless mini-split system, you will have an outdoor AC unit and an indoor unit. Portable and window air conditioners have all of their components in one unit.
The outside unit houses the condenser coil and the compressor while the indoor unit has the evaporator coil and the expansion valve. The components are connected together using copper tubing and Freon gas is circulated between all the parts where it changes from gas to liquid as it takes heat from the house.
The following processes illustrate how Freon (and any other refrigerant for that matter) works in an ac system:
1. Compression
High-temperature and low pressure Freon gas from the house first enters the compressor where it is compressed, increasing its pressure significantly. Old AC units have a piston compressor while newer ones use a scroll compressor.
One important thing to know here is that as the pressure of the Freon gas increases, its temperature increases as well. That is just a rule observed by all gases.
Since the Freon gas is carrying heat from the house, it needs to remove it to the outside air before it goes back for another cycle of cooling.
As such, it is important for the temperature of Freon gas to be higher than that of the surrounding air. In thermodynamics (heat transfer), heat is transferred from a point of high concentration to a point of low concentration.
2. Condensation
The now high-pressure superheated Freon gas enters the condenser coil. Condensation is basically the conversion of a gas to its liquid state.
Inside the condenser unit, Freon needs to lose the heat it removed from the indoor air and also cool enough so that it goes back to its liquid state.
That is made possible by a fan which blows cool air over the condenser coil. A condenser coil is made of many coils of copper tubing which increases the surface area for maximum heat exchange.
As the fan blows cool air over the condenser coil, the air absorbs the heat from Freon and dissipates it to the surrounding. That is why the air around your condenser unit is quite hot.
By the time Freon is exiting the condenser coil, it will have lost so much heat that it will be almost in its liquid state.
3. Expansion
Freon leaving the condenser coil is still under high pressure. If it is allowed to enter the evaporator coil as such, all of it will not evaporate and some liquid Freon will go back to the compressor and damage it.
To prevent that, a device with a small restriction is installed just before the evaporator coil. This device is called an expansion valve.
An expansion valve basically controls the amount of refrigerant entering the evaporator. The restriction also helps to lower the pressure of the Freon.
As we saw earlier, increasing pressure results in an increase of temperature. Lowering the pressure then ensures that the temperature also reduces drastically.
The reduced temperature of the Freon (now in its liquid state) ensures maximum heat exchange between the hot indoor air and the Freon refrigerant.
4. Evaporation
Cold Freon in its liquid state enters the evaporator coil which also has cylindrical fan known as an impeller fan. The fan draws in hot air from the house and forces it over the evaporator coil where the cold Freon is flowing through.
Freon absorbs heat from the hot air and starts to evaporate. The cooled air is then sent back to your house as the vaporized Freon is ejected out of the evaporator coil and sent back to the compressor.
The cycle goes on and on until the air inside your house is cooled to your satisfaction.
Impact of Freon on the Environment
Being non-toxic, Freon eliminated the dangers posed by older types of refrigerants like ammonia. That is exactly why all the cooling systems at the time used it as a refrigerant.
To drive the point home even further, Thomas Midgley felt obliged to demonstrate the admirable properties of Freon to the to the American Chemical Society.
Thomas inhaled a good amount of Freon gas then blew it out onto a candle flame which was instantly extinguished. By so doing, he was able to demonstrate that Freon was both non-toxic and non-flammable.
Although Freon was a safer and excellent refrigerant than ammonia, it was later discovered that the gas caused serious depletion of the ozone layer. Depletion of the ozone layer in return resulted in global warming.
The Montreal Protocol and the Freon Phase Out
In 1987, the United States and other nations entered into a global agreement known as the Montreal Protocol. The main aim of the protocol was to phase out the use and production of ozone-depleting substances, Freon being one of them.
According to the United Nations Environmental Program (UNEP), the most commonly used hydrochlorofluorocarbon (HCFC) is nearly 2000 times more potent than carbon dioxide in terms of its global warming potential.
The phase out of Freon as a refrigerant begun in 2004 and in its place safer refrigerants have are being used in modern air conditioners.
Production of HCFCs by developed nations reduced since then and the gases were completely phased out in 2020. Developing nations are expected to do the same by 2030.
In 2010, the Unites States’ Environmental Protection Agency (EPA) banned the production and installation of Freon-reliant cooling systems/appliances.
The main replacement of Freon (R-22) is R-410A, or as known by the following brand names:
- Puron®
- SUVA 410A®
- GENETRON AZ-20®
- Forane® 410A
So, what happens if your air conditioner still uses Freon as a refrigerant?
The good thing is that air conditioning systems are closed-looped systems and you will hardly need to top-up the refrigerant unless there is a leak somewhere.
If you own an aged and problematic air conditioning system, a replacement with modern air conditioning systems is considered a better choice than trying to fix it.
If your air conditioning system still uses Freon, an HVAC technician can recharge it using recycled Freon. The question you are possible asking yourself is “Can I use R-410A in my old air conditioner instead of R-22”?
Surprisingly this is not a Yes or No answer. It depends on the type of system you have.
Some of the new refrigerants can be used in the old R-22 systems but most of them aren’t. Although conversions/systems overhaul are possible, the difference in cost between it and installing a newer system isn’t worth it.
How Do I know if My AC uses Freon?
Head outside to the outdoor/condenser unit and look for a white label or plate. The plate has a lot of information one of them being the date of manufacturing.
If your air conditioning unit was made in 2015 or after, you definitely are not using Freon as a refrigerant. The last ACs that used Freon were made in December of 2014.
The plate/label should also indicate which refrigerant the AC uses. If you see R-22 or HCFC-22 then you have definitely have Freon. R-410A indicates your AC uses the modern refrigerant.
Wrap Up
And that is basically everything you would want to know about Freon as a refrigerant. I hope that this guide was beneficial to you.