The Role of Fluorochemicals in Refrigerants
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Refrigerants - Just What Are They, Anyway?
Some things you may not have been aware of when dealing with refrigerants:
- They look like water when you see them through a transparent area for viewing. They are liquid and vapor in different parts of the refrigerator to make the system work.
- Although refrigerants look like water, they have properties much different than water. If you would open a container holding a refrigerant in its liquid/vapor state, it would all turn to vapor very quickly. Why?
- When enclosed, refrigerant is kept under great pressure.
- A common refrigerant will boil at minus 38 degrees F and any temperatures above! Once a container holding refrigerant is opened in normal air pressure, it will boil and vaporize instantly.
What Are Used As Refrigerants?
In the "old days", ammonia was often used as a refrigerant. This practice was discontinued in the early 1900s, as ammonia has a very unpleasant odor which accompanies it. Even a small leak could cause quite a "stink". If a larger leak or total breakdown occurred with mechanisms using ammonia as a refrigerant, the amount of gases released were toxic. New refrigerants needed to be created for the safety of anyone using them.
Chemicals, or fluorochemicals, are now used in these items as refrigerants. The industry which created fluorochemicals, which are organic fluorine-containing compounds, began in earnest late in the 1920s. The discovery of fluorochemicals has been attributed to the United States' Thomas Midgley Jr. Numerous compounds containing fluorine are hazardous and poisonous, but Mr. Midgley found several nontoxic and nonflammable varieties. What made these nontoxic varieties perfect were that they had the exact properties needed in a refrigerant, while also being odorless!
There are several fluorochemicals that were commonly used until quite recently, like chlorofluorocarbons, also known as CFCs, and hydrochlorofluorocarbons, also known as HCFCs. In the trade, both CFCs and HCFCs may be referred to by the familiar DuPont trademark - Freon. These chemicals, although effective, were phased out of cooling mechanisms and appliances due to the damage they cause to the ozone layer. They are being replaced with tetrafluoroethane, a hydrofluorocarbon (or HFC) also known as R-134a or Freon 134a.
What Is The Role Of Fluorochemicals As Refrigerants?
Basically, the role of any compound, whether it be a fluorochemical or not, used as a refrigerant is to keep things "cold". In reality, "cold" is an abstract idea, since everything actually contains heat. Something that a person finds "cold" is just something that is at a lower temperature than something else. Yes, ice and snow is "cold" when a person holds it in their hand, but that is only because that ice and snow is at a lower temperature than the human body.
When looking at fluorochemicals used as refrigerants, we will see that reducing their pressure will cause the compound to absorb heat as it vaporizes. If you would happen to spill a liquid refrigerant on a hard surface, it would not only vaporize instantly, but it would also take a lot of the heat out of the surface it landed on. That area of the countertop or floor would feel "cold".
So, what is done in many mechanisms is the refrigerant's vapor pressure is raised with a compressor. This gets the vapor quite hot, but cooling the hot, high pressure vapor with room air condenses the vapor back into a liquid again (just like steam on a cool surface). Once the refrigerant is a liquid again, the refrigerant flows into another tube where the pressure is lowered and it vaporizes again. This is where it absorbs heat and creates the "cold" environment.
After being moved through the "cold" lower pressure areas of the mechanism, the refrigerant vapor is compressed again. Thus begins the entire cycle over again and keeps the cooling appliance working in the manner it was intended. With proper use and care, these mechanisms can create an environment of "cold" for a very long time.
Fluorochemical Refrigerants Are an Important Part of All Cooling Devices
As you can see, fluorochemicals are an indispensable part of any device that is used to drop the temperature in an area or appliance. Whether it is a refrigerator, freezer or air conditioning unit, nothing would be accomplished without the refrigerants found inside. Due to their importance in creating a state of "cold", fluorochemicals have become a topic of great interest.
More and more research is being done every year to make fluorochemicals more effective as refrigerants. Older fluorochemicals had potential downsides, such as deteriorating the ozone layer and increasing the risk of future "global warming". However, companies like DuPont are working to create other compounds that work just as effectively, without the worry.
About the Author
Craig Elliott is a writer for halocarbon.com. Halocarbon.com is a leading provider of Fluorochemicals | Anesthetics
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