For numerous years, hydrofluorocarbon (HFC)-134a was the alternating refrigerant of choice to change chlorofluorocarbon (CFC)-12 in countless medium- and also high-temperature stationary refrigeration, wait conditioning, and also automotive air conditioning applications. The pressure/temperature relationship and also the latent heat values of R-134a are very comparable to those that R-12. Also, R-134a is a an extremely safe refrigerant through an ASHRAE safety classification of A1. This method it is no flammable and also has very low toxicity levels. Due to the fact that HFC-134a has actually no chlorine in that is molecule, it has a zero ozone-depletion potential (ODP) and doesn’t deplete the stratospheric ozone layer.
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R-134a is not a refrigerant blend. That is considered a pure compound and has just one molecule. The R-134a molecule is ethane-based and also consists of carbon (C), fluorine (F), and also hydrogen (H).
EVAPORATOR TEMPERATURE APPLICATION
As a medium- and also high-temperature refrigerant, R-134a is no usually used in low-temperature applications. R-134a loses some capacity when compared to R-12 in low-temperature applications. At reduced temperatures, R-134a has actually a slightly reduced pressure 보다 R-12, and also at higher temperatures, R-134a has actually a bit of a higher pressure when contrasted to R-12. Otherwise, both refrigerants’ pressure/temperature relationships closely compare.
R-134a often operates with a really low push — if not a slight vacuum — in low-temperature applications. At around minus 15°F evaporating temperature, R-134a beginning to fall into a vacuum. These reduced pressures in lower temperature applications cause greater compression ratios, higher discharge temperatures, and low efficiencies — not to mention included stress ~ above a system’s compressor.
R-134a refrigeration solution use fabricated polyolester (POE) lubricants while the automotive industry typically has offered polyalkylene glycol (PAG) lubricants. Polarity differences between commonly supplied organic mineral oils and HFC refrigerants make R-134a insoluble, thus incompatible with mineral oils the were supplied in countless refrigeration and also air air conditioning applications. R-134a was never intended to be a straight drop-in instead of for any kind of refrigerant, and also retrofit guidelines had to be complied with when retrofitting a system to R-134a.
GLOBAL WARMING LEGISLATION
R-134a has a global-warming potential (GWP) that 1,430. This means it traps 1,430 times together much heat per kilogram as carbon dioxide does end a 100-year period. Because R-134a has actually such a high GWP, the U.S. Environmental Protection company (EPA) noted R-134a together an “unacceptable” refrigerant for specific refrigeration and also air air conditioning applications under its far-ranging New choices Policy (SNAP) program. These applications include:New light-duty motor vehicle air conditioning, beginning in 2021, v a few narrow usage limit exceptions. The exceptions are for newly manufactured light-duty vehicles destined for use in countries that carry out not have actually infrastructures in place for servicing with other acceptable refrigerants. The narrow usage limit will proceed through design year 2025;Beginning in model year 2026, R-134a will be i can not accept for use in all newly produced light-duty vehicles;New vending makers as of Jan. 1, 2019;New stand-alone, medium-temperature units through a compressor capacity listed below 2,200 Btuh not containing a flooded evaporator as of Jan. 1, 2019; andNew stand-alone, medium-temperature units with a compressor capacity equal to or higher than 2,200 Btuh and also stand-alone medium-temperature systems containing a flooded evaporator as of Jan. 1, 2020.
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SOME R-134a instead of OPTIONS
There are a number of candidates to replace R-134a in the applications for which it will certainly be reputed unacceptable through the EPA.HFO-1234yf — Hydrofluoroolefin (HFO)-1234yf is a low-GWP replacement for R-134a plan for usage in mobile air conditioning solution in the automotive industry. It has actually an ODP of zero and also a GWP the 4. HFO-1234yf’s GWP is more than 300 times less than that of R-134a. Countless European and also some U.S. Car manufacturers are at this time using HFO-1234yf for mobile air air conditioning applications. HFO-1234yf has actually one of the lowest switching cost for automakers contrasted to other alternatives. It is classified as a low-toxicity but slightly flammable refrigerant by ASHRAE through an A2L security classification. The continued advancement of standards and codes because that safe usage of mildly flammable A2L refrigerants is really important. HFO-1234yf is miscible in POE lubricants. The miscibility that HFOs v POE lubricants is comparable to that of R-134a. HFOs space not dissolve in mineral oil or alkylbenzene lubricants.HFO-1234ze — HFO-1234ze have the right to be provided in vending machines, refrigerators, beverage dispensers, air dryers, and also carbon dioxide cascade solution in advertising refrigeration. It has an ODP of zero and a GWP the 6. Various other applications incorporate both air- and also water-cooled chillers in supermarkets and commercial buildings. HFO-1234ze provides excellent power efficiency, is cost-effective, and can be used in present equipment design with minimal changes. HFO-1234ze also offers advantages over R-32, which has actually a medium GWP, an A2 refrigerant safety and security rating, and also high discharge temperatures. The miscibility the HFO-1234ze with POE lubricants is similar to the of R-134a.HC-290 (Propane) — Hydrocarbon (HC)-290 has actually an A3 safety team classification, meaning it is very flammable. Its molecule consists of nothing yet hydrogen and carbon. It has an ODP of zero and also a GWP the 3. As long as the refrigerant fee doesn’t exceed 5.3 ounces (150 grams), it deserve to be supplied in freezers, family refrigerators, combination refrigerators and freezers, room wait conditioners, and also vending machines. As with the A2L refrigerants, the continued advancement of standards and codes because that safe use of flammable refrigerants is very important.HC-600a (Isobutane) — favor HC-290, HC-600a has actually an A3 (highly flammable) safety group classification. That is molecule includes hydrogen and also carbon. It has actually an ODP of zero and also a GWP the 3. As long as the refrigerant fee does no exceed 2 ounces (57 grams), it have the right to be used in vending machines and retail food refrigeration (stand-alone commercial refrigerators and freezers). Again, the continued advancement of standards and codes for the safe usage of HCs is really important.R-513A — R-513A is one HFO/HFC blend v an ODP the zero and also a GWP of 631. R-513A has a close performance match to R-134a for new and retrofitted systems. The is the shortest GWP refrigerant in the A1 safety group to replace R-134a in stationary systems.R-450A — R-450A is a near-azeotropic refrigerant blend containing an HFO refrigerant design to change R-134a in commercial and also industrial refrigerators as well as air conditioning and also chillers. It has actually a an extremely low temperature glide and also can be used in straight expansion or flooded evaporator systems. The is compatible through POE lubricants.
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