Explosion hazards are a danger in many industries, for example the oil & gas industry or the petrochemical sector. Minimizing the danger is paramount, particularly on a ship at sea, for example, or an offshore oil platform.
Frankly, any manufacturing or resource industry that operates under the ATEX directive is probably a candidate to consider an R410A retrofit—and there are plenty of those. The purpose of ATEX is to limit or prevent explosion hazards—and the replacements for CFCs, or chlorofluorocarbons, are not as safe for employees or infrastructure in an environment where the threat of fires and explosions are inevitable daily hazards.
Governments and companies are becoming more committed to preventing climate change every day. Through strict regulation of CFCs, our planet’s Ozone Layer has been restored completely. This article thoroughly discusses the differences between R410-A and R32 and explains why R410-A is still used today.
History of refrigerants
Mechanical refrigeration based on the vapor/compression cycle was invented in 1834. Over the years, the refrigerants used were poisonous, corrosive, flammable, and intrinsically dangerous—they caused many deaths due to these toxic substances leaking, which included the likes of ether, methyl chloride, ammonia, and sulfur dioxide.
In 1913 the first home-use electric refrigerator was invented, costing twice as much as a car. Although fairly safe, deadly danger existed if they failed in any way. One particularly grisly newspaper story about an entire family perishing overnight because of a leak inspired Albert Einstein and Leó Szilárd to develop several versions of a safer fridge. Their best-known design used ammonia, butane, and water, required no electricity (a useful feature when electricity was still a novelty in many 1920-1930 homes and certainly not as ubiquitous as today), and was powered by a tiny flame driven heat source.
Once Freon™ became available in the 1920s, this non-lethal, non-toxic, non-flammable, tasteless, odorless gas replaced nearly all of the dangerous substances that had been used prior. Freon occurs in numerous varieties, including R-12, R-13B1, R-22, R-410A, R-502, and R-503; many chemically similar halocarbon refrigerants like these do not use the proprietary name “Freon”.
Refrigerants & Ozone Depletion Potential
Our atmospheric oxygen is found as a double-bond molecule called O2. The intense UV light from the Sun can occasionally sever that bond.
Single atoms of monoatomic oxygen (O) don’t like to be separate, so they will quickly rejoin with another oxygen atom, if available. Otherwise it will join with an O2 molecule to form O3, or Ozone. O3 has weaker bonds than O2, so it is subject to molecular disruption.
Despite its rarity of ~3 ppm (parts per million), ozone is responsible for attenuating UV light energy before it reaches the troposphere where we live. If we didn’t have the ozone layer you would acquire skin-peeling and potentially life-threatening sunburn in about five minutes, if you were to go outside.
The villain, ozone-depleting substances
This was a scenario we strongly wished to avoid back in 1984 when the “ozone hole” over the Antarctic was discovered. We suddenly knew that controlling CFCs was a vital task if the Earth was to sustain life beyond 2065.
That is why just three years later, in 1987, 197 countries signed the Montreal Accord to eliminate CFCs from most uses. No more hairspray, spray paint, and deodourant using CFC propellants; no more poorly manufactured automobile or household air-conditioning or refrigeration units; no more use as degreasers in the electronics industry; no more use as blowing agents in the plastics industry; and, no more use as industrial solvents.
Freon and related compounds are the CFCs. These have been determined to be ozone-depleting substances when released into the atmosphere from sources such as those mentioned above.
Simply put, escaping CFCs rise slowly through the atmosphere until they reach the stratosphere, whereupon incoming UV radiation tears the molecule apart. A free-floating chlorine molecule will seek to join with oxygen to make chlorine monoxide.
If it stopped there it wouldn’t be a problem, but chlorine and oxygen don’t have a very strong bond so the UV splits them again. Then chlorine finds another ozone molecule and steals its spare oxygen—and then splits again and finds another…
One chlorine atom can repeat this 100,000 times before it connects with something heavy enough to make it precipitate out of the atmosphere. Ozone depletion isn’t a fast process. In fact, ozone is so rare that if you compressed a column of our entire atmosphere to sea level pressure (making it about 8 km tall), the ozone layer would only be 3mm thick, like a coin. The problem is that atoms of chlorine can persist and bounce around for decades doing a lot of harm before it is eliminated.
R410-A vs R32
R32 is well known as the more environment friendly successor of R410-A. Thus, manufacturers are phasing out R410-A as we speak. Producing R410-A units is by no means illegal, but OEM’s have to meet imposed quota and are committed to lowering their emissions. A common misconception is that R410-A damages the ozone layer, as explained before. The ODP (Ozone Depletion Potential) of both refrigerants is actually zero. The difference with regards to the environment lies within the GWP (Global Warming Potential). The GWP of R32 is 675, whereas the GWP of R410-A is 2.088. For comparison, the GWP of R-508B is 13.396.
Furthermore, R32 is about 20% more efficient than R-410A. This brings down operating and maintenance costs. So, what about recycling? R32 is the winner once again, it is easier to recycle because this refrigerant is single component.
However there are also benefits to R410-A in certain situations. Ex-Machinery has noticed that a lot of clients still require R410-A because:
- Within the maritime industry R410-A is still the standard for most end-users when it comes to ATEX zones. Therefore they require installers and procurement companies to source R410-A A/C units.
- R410-A is allowed to be transported by plane. R32 is forbidden in air transport because it is considered a dangerous good. When clients are in a hurry, they often request R410-A units.
- R32 is still relatively new and also mildly flammable. Not all countries and installers are familiar with R32, therefore they will not accept it in their projects.
- Larger installations, such as VRF equipment for cooling buildings, are required to use R-410A as opposed to R32. If the R32 leaks into a small room within the building due to a defect, the amount of R32 in the air could exceed the Lower Explosion Limit (LEL). This would create an explosive atmosphere, which we try to prevent at all times.
Certified R410-A Retrofit
The existing R32 systems being sold nowadays can be re-engineered to use R410A safely. This procedure is called a R410-A retrofit. Retrofitting is not straight-forward and requires extensive knowledge.
For example R32 runs at pressures 1.6 times greater than that of R410-A, so thicker copper tubing is required throughout the device. The seals must be more robust than earlier designs, too, because ultimately most leaks arise from vibrations from the compressors during operation, expansion and contraction of the metal parts during temperature changes, or simply from pressure changes occurring depending on whether a compressor is running or idle. Therefore R32 units are significantly different from R-410A units in design and steering. During the retrofit both aspects must modified accordingly to ensure safe and energy efficient operation of the retrofitted unit.
There are very few companies that are certified to perform these retrofits. Among others, we work with the world’s #1 leading OEM air conditioning company, Daikin, selected as an Advanced Global Company for Climate Change Measures on the CDP’s Climate Change “A” List. Daikin carries a label and certificate for this work, so the quality and reliability of their work is as impeccable as our own—and we wouldn’t have it any other way because we know the value of expertise!
In most cases R32 is the superior refrigerant when compared to R410-A. While neither refrigerant depletes the ozone layer, R32 has a lower GWP and is easier to recycle. R32 also has lower operating and maintenance costs and is nowadays more common than R410-A due to the phase out.
In several situations R32 is not desired, for example when quick (and cheaper) transportation is of importance. The pros of R410-A are especially present in industries dealing with hazardous areas.
Ex-Machinery is proud to work with OEM Daikin to provide clients with R410-A retrofitted ATEX a/c units. Please reach out to us for more information.