Refrigerant Types, History & Future
When we talk about refrigerants, we mean a fluid that is able to easily evaporate and condense continuously. We learned how a refrigerant works in our last post which you can access by clicking here.
The historic and current main types of refrigerants are
- CFC – ChloroFluoroCarbons
- HCFC – HydroChloroFluoroCarbons
- HFC – HydroFluoroCarbons
However, all of these have been or will be replaced in the future because of their effects on the environment. So if you’re working in the refrigeration industry or studying to enter it, you will see a big transition into the next generation over your career.
Now unless you’re one of the scientists developing these refrigerants then you don’t really need to know what all the numbers and letters mean, but you should know the basics. The “R” simply means refrigerant, the numbers mean the quantity of each atom with each digit corresponding to a specific type, and the small letters at the end give a scale of the symmetry of the compound. (Blank, a,b or c).
What does the future of refrigerants look like?
The market is heading in the following directions. One route is the natural refrigerants such as Carbon Dioxide, Ammonia, and Hydrocarbons. These all have very low global warming potential some even zero, they have good thermodynamic properties also and most are fairly cheap to manufacture. HFO’s are stepping in to replace many HFCs as these have much lower global warming potentials and do not destroy the ozone although some are flammable.
With the new laws and regulations coming in, you’ll have to start retrofitting your systems over to new refrigerants, and we will look at more detail of that in the next article, but one thing to consider for now is the glide of the retrofit blend refrigerants as some of these are quite high. Consideration must be taken for the refrigeration system components to ensure they will function optimally using these different refrigerants.
A brief history of refrigerants
In the early day's natural refrigerants were used, but, there were little to no safety regulations so systems ended up using very dangerous refrigerants. Some were highly flammable and some were even toxic! Soon scientists realized the market's need for better and safer refrigerants.
Then in the 1930s, they developed CFCs, which were scientifically tested and were safer to use. They were nonflammable, nontoxic and a noncorroding gas which was cheap to produce, so they seemed ideal. However, in the 1970s they realized that the chlorine molecules within these were completely destroying our ozone layer and were banned. We’ll look at why just shortly.
In the late 1970s, early 1980’s scientists developed HCFC’s which had far less damaging effects on the ozone, however, HCFC’s were still able to damage the ozone layer because they contained chlorine molecules, again we will look at why these are bad in just a moment.
How did the hole in the ozone layer form?
The ozone-depleting chemicals rise up into the stratosphere and the chemicals are swept into the winds of the polar vortex, which is a ring of fast-moving air that circles the south pole, and the chemicals have been building up here since CFC refrigerants first started being used.
This build-up in the south pole has been destroying the Ozone layer by burning a hole through it. The laws and regulations on the use of chemicals in refrigerants have been increasingly tightened over the years and as this continues the plant will have time to repair this hole. Let's just briefly learn why and how this has been burning a hole in our Ozone layer.
If we look at our planet. First, we have the troposphere and then we have the stratosphere. The Ozone layer exists within the stratosphere. The ozone layer protects us from the sun's UV rays which are very harmful and cause cancer.
Within the ozone layer, we have the Ozone molecule which has 3 oxygen atoms, which absorb the UV rays. The CFC molecules rise up into the stratosphere and the UV rays cause the chlorine atoms to break off.
This separation of the chlorine atom causes a chemical reaction, resulting in the chlorine atom stealing an oxygen atom from the ozone molecule. This creates a chlorine monoxide molecule and a separate oxygen molecule. The Ozone layer is unable to support these new molecules and so a gap is formed in the stratosphere. The bigger the hole gets, the more UV rays will be able to reach us.
Global Warming Potential
The other problem with refrigerants is their global warming potential. What should happen is the infrared rays pass through our atmosphere, hit the surface and most are rebounded back into space with a few rebounding and staying within the atmosphere.
Scientists since discovered that many of the chemicals in the refrigerants prevented infrared rays from pass through them, so as they build up in the atmosphere they prevent the rays from leaving which causes heat treatment and this is leading to climate change. Although there are many contributors to this and not all are man-made.
To solve the issue of ozone destruction scientists came up with HFC’s which did not contain chlorine, this meant they wouldn’t destroy the ozone layer. However, they later realized HFC’s still damage the environment because they are greenhouse gases and so these are beginning to be phased out also.
Now, like I mentioned earlier, we are seeing the 4th generation of refrigerants emerge into the market which has great thermodynamic properties and is environmentally friendly.
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