First of all, what is a Refrigerant? Well, it is a fluid that possesses the desired thermodynamic & other essential properties and that undergoes various phase changes from a gas to liquid and back to gas before entering the compressor all as part of a single closed-cycle called the Vapor compression cycle with the ultimate aim of producing ‘a cooling effect.’
It all began with water being used as one of the first and oldest refrigerants/mediums used for cooling followed by ammonia, sulfur dioxide, methyl chloride, etc. but all had limitations with respect to toxicity, flammability, corrosiveness and had to be replaced considering safety & health hazards. Ammonia is still used for larger applications in vapor absorption cycles.
This led to the inception of the CFCs (chlorofluorocarbons) with R-12 being the most common and widely used CFC as they have excellent thermodynamic properties, are non-toxic & non-flammable in nature. But then there is no rose without thorns. R-12 contributed tremendously to the depletion of the ozone layer with decades of dumping harmful reactive pollutants like chlorine into the stratosphere. CFC molecules & bonds break down on exposure to UV rays and the now unchained chlorine from it reacts with ozone (O3) thereby destroying it completely.
Why is protecting the Ozone layer important? The Ozone layer acts as a barrier or shield that prevents us humans from directly being exposed to the harmful ultraviolet radiations emitted by the sun. If not for the ozone layer, exposure to these UV rays would have led to various complexities such as skin diseases, cancer, damage to plants and animals, cataract etc. Various atmospheric measurements and rise in global warming already indicate how harmful can the depletion of ozone layer be.
The introduction of R-22 an HCFC (hydrochlorofluorocarbon) did not help in completely eliminating the issue of ozone depletion. R-22 having a lesser concentration of chlorine controlled this damage to an extent but damage was still being done. Though their Ozone Depleting Potential (ODP) is low, their Global warming potential (GWPs) is quite high & posed as a potential threat. ODP & GWP is the ability of a gas to contribute to the ozone layer depletion and cause the average temperature of the earth to rise respectively.
Loads of scientific research and experiment finally led to the development of R407C & R410A. HFCs (Hydro fluorocarbons)that eliminated the use of chlorine meaning they have zero ODP & moderate GDP. HFCs are not single but rather a blend of gases. R407C is a ternary mixture of hydrofluorocarbons (HFCs) i.e. HFC-32 or difluoromethane which has excellent heat transfer performance, HFC-125 or pentafluoroethane reduces flammability as it is a fire suppressing agent & HFC-134a or tetrafluoromethane due to its low boiling point. R-410A is a binary mixture of hydrofluorocarbons (HFCs) i.e. HFC-32 & HFC-125.
R-407C is a perfect replacement for R-22 as their operating pressures are the same but being an eco-friendly gas it is rightfully more expensive than R-22 but less costly than R-410A. R-410A has high overall efficiency based on performance compared to R-22 & R-407C both. They operate also at high suction & discharge pressures thereby demanding high-pressure compressors and hence cost more than R-22 & R-407C. Considering their zero ODP and moderate GWP & also the possibility of a ban on R-22, R-407C or R-410A should be the natural choice of gas for your upcoming plant. HVAX has been supplying & installing all chilling units using eco-friendly gases such as these.
The objective up next is to get the GWP also to zero considering it is a global environmental concern. HFCs contain fluorine which contributes to global warming & efforts are being made to find replacements. HFOs & HCs both are potential contenders but they face a common hurdle of falling under the flammable category making it a riskier option.
Refrigerants have evolved tremendously over the years leading to better, less harmful choices & with the growing concerns pertaining to global warming, one with negligible threat to the earth will be out soon.
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