High global warming potential (GWP) refrigerants have always been a matter of concern and discussion not only for organisations, such as Environmental Protection Agency (EPA) and the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) but also for the global HVACR fraternity in general.

As per the EPA Web site, GWP was developed to allow comparisons between the global warming impacts of different gases. The larger the GWP, the more a given gas warms the Earth compared to CO₂ over that period of time. Chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF₆) are sometimes called high-GWP gases because, for a given amount of mass, they trap substantially more heat than CO₂, the Web site says.

Industry experts are of the view that the search is always on to identify the best refrigerants for low-, medium- and high-temperature applications. Dr Rajan Rajendran, Vice President of Systems Innovation Centre and Sustainability at Emerson Climate Technologies, says: “In our quest to produce lower-GWP and higher-efficiency products worldwide, Emerson invests a considerable amount every year in research and development. We are also active members of several committees, such as Air Conditioning Heating and Refrigeration Institute’s (AHRI’s) Low GWP Alternative Refrigerant Evaluation Program, that work on testing and evaluating alternative refrigerants.”

Dr Veerle Beelaerts, Environment and Compliance Specialist at Daikin Middle East and Africa, believes that there are a number of factors that need to be considered when choosing the next-generation refrigerant. She elaborates: “We assess the chemical characteristics of the gas itself, such as the Ozone Depletion Potential (ODP) and GWP value, toxicity and flammability characteristics. We also look at the impact on the design of the equipment, energy efficiency – also in high-ambient conditions, and safety – also for people installing and servicing the equipment.” She, however, cautions that there is no one-size-fits-all solution for every application.

Stuart Corr, TechnoCommercial Director at Mexichem Fluor, agrees with Dr Beelaerts and says that Mexichem has had a long history of developing refrigerants that have the best balance of properties across a range of application sectors. “Both safety in use and environmental impact are the key driving forces for the development of refrigerants with energy efficiency being the principle environmental driver,” Corr explains.

An alternative view

Keeping safety, environmental impact and energy efficiency in mind, Corr says that there is a range of safe and efficient alternatives to CFC and HCFC refrigerants that are commercially available. He elaborates: “Leading these are HFCs which cover all of the major application areas, including low-, medium- and high-pressure applications. These HFCs include R410A, R407A and R134A.” He points out that there are a number of low-GWP refrigerants under development that include R32 and the hydrofluoroolefins (HFOs) R1234yf and R1234ze, which are at the early stages of commercialisation.

Speaking on behalf of Emerson, Dr Rajendran adds, “In air conditioning for the Asian market, we have announced several R32 products, and in refrigeration, we recently released products for R448A, R449A, R450A and R513A.” Dr Beelaerts believes that more and more alternatives may become available in the coming years.

Phase-off

Despite the many alternatives available, high-GWP refrigerants, such as HFCs are still very much in use, with no sight of a phase-out or a phase-down. During the 35th meeting of the Open Ended Working Group (OEWG35) of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer, held in Bangkok in April this year, Clare Perry, Head of Climate for the Environmental Investigation Agency (EIA), said that there were oppositions from certain Gulf countries when the HFC phase-down amendment proposal was presented. “The primary opposition seems to come from Saudi Arabia, Bahrain and Kuwait,” Perry revealed in an interview with Climate Control Middle East. “The reason stated for their opposition is the concern over the availability of HFC alternatives that work in the high-ambient temperatures that they typically experience,” Perry said. “While there is certainly an additional challenge in phasing out HFCs in high ambient temperatures, there is enormous innovation in technology and increasing availability of alternatives.” Henrique Pereira, Managing Director at Seabra, explains the issue more clearly. He says: “The phasing-down of HFCs has long become an emotive subject for the cooling industry, effectively polarising people into two camps. In camp one are those that believe we should retain the ability to use the most energy-efficient gases available, thereby minimising indirect emissions at the power station, and that the ongoing focus should be on improving containment.” He thinks that the people in this camp argue that the potential cost, training burden and lack of cast-iron data about the alternatives make it too risky to consider a speedy replacement.

“In the other camp,” he explains, “are those who believe that the GWP of HFCs, combined with the industry’s historic inability to keep it in the system, provide too potent a cocktail for the environment, and therefore, the gases should be replaced as soon as is practically possible with less environmentally harmful gases.” This other group, he believes, argues that the potential benefits of the alternatives outweigh the difficulties to such an extent that imposing restrictions on HFCs will spur the industry into solving the problems of training and cost. Belonging to the former camp is Abin P Kurien, Sales Manager at the Refrigeration and Air Conditioning Division at Naser Al Sayer & Company (NASCO), who is of the opinion that refrigerants are only a minor cause for global warming, whereas there are many other sectors that contribute in much larger proportion. He adds, “While shifting to low-GWP refrigerants, there are many limitations on the refrigerants, like flammability, higher operating pressures, etc., compared to many of the currently prevalent refrigerants. These factors increase the equipment and control costs for new plants as well as for retrofitting. Hence, we prefer to not move as aggressively from the current bouquet of synthetic refrigerants.”

Giving a breakup of which HFCs are used where, Kurien reveals that HFCs like R134A  as well as HFC blends like R404A, R410A, R407C are commonly used in the UAE region. “R134A is a common refrigerant in automobile air conditioners, commercial and domestic refrigeration etc. R404A is used in commercial refrigeration, whereas R410A and R407C are used mainly in air conditioning,” Kurien elaborates.

Dr Rajendran is of the opinion that HFCs, like all chemicals, when used properly provide valuable cooling, heating and refrigerating effects in a very efficient and cost-effective manner. He thinks the problem occurs when systems leak or when HFCs are vented into the atmosphere. Dr Beelaerts argues that HFCs do not deplete the ozone layer, as they were alternatives for HCFCs. “However,” she says, “they [HFCs] are still greenhouse gases and their growing use is a concern, and this is why the industry is looking for alternatives with a lower global warming impact, such as HFCs with a lower-GWP value or HFOs and non-fluorinated refrigerants.”

Giving a brief history of the evolution of refrigerants, while also supporting Dr Beelaerts’ statement, Corr says that highly toxic and/or flammable refrigerants, such as sulphur dioxide (SO₂), ammonia and ether were replaced in large part by halogenated refrigerants, such as CFC12 and later HCFC22, which provided a good combination of safety and performance. However, he adds that with the recognition that CFCs and HCFCs were responsible for ozone depletion, they were replaced with HFCs, such as R134A. Although SO₂ and ether no longer have any role in modern refrigeration, ammonia, hydrocarbons and carbon dioxide (CO₂) continue to have a role in specific application sectors, but are not used as extensively as HFCs, Corr points out.

Kurien believes that the development of refrigerants over the next decade will trend towards low-GWP HFC blends to hydrocarbons (HCs) and natural refrigerants.

Naturally speaking

This leads one to wonder if natural refrigerants would be the best bet, both economically and ecologically, in the entire refrigerant scenario. Dr Rajendran does not think so. “Natural refrigerants are too broad a class to make a general statement,” he says. “Higher pressure, poor high-ambient performance (CO₂), flammability (propane) and toxicity (ammonia) are associated with natural refrigerants, on a case-by-case basis. The total cost of ownership will vary depending on the equipment, refrigerant and usage.” Corr concurs with Dr Rajendran, and adds, “There are no inherent economic advantages with natural refrigerants. What needs to be considered is the total cost of the use of a refrigerant, including measures taken to accommodate flammability or toxicity, as well as energy efficiency. Accordingly, we should focus not on the natural versus synthetic aspects of refrigerants but rather on their overall lifecycle carbon emissions.”

Dr Beelaerts elaborates further that hydrocarbons, ammonia and CO₂ can provide ecological and economical solutions for some types of applications, such as standalone fridges/freezers, portable air conditioners, industrial refrigeration and large-sized supermarket systems. She, however, highlights that they are not suitable alternatives in other types of applications.

The future of refrigerants

In light of Kurien’s earlier remark, in the future, there could be blends of HFCs and natural refrigerants. “The development of lower-GWP synthetic refrigerants will continue, and the adoption of natural refrigerants, like CO₂, propane and ammonia, will also continue to increase,” is Dr Rajendran’s view.

Suresh N Sharma, Regional Manager Industrial Refrigeration, Sales (MENA), at Danfoss, and Pereira lean towards ammonia and natural refrigerants when it comes to the refrigerant of the future. “Looking at the global trend,” Sharma says, “there will be a time when heavy commercial refrigeration will have to come to a standstill and applications of ammonia and other natural refrigerants will go up.” He optimistically adds, “Such natural refrigerants will totally take over the entire industry.”

However, Dr Beelaerts is of the view that manufacturers of equipment will continue looking for ways to reduce the CO₂ eq refrigerant charge, by using refrigerants with a lower GWP, and also by trying to reduce the charge quantity, while still aiming for high energy efficiency, safety and economic viability. “It is a design challenge,” she says. “But we already see many new types of equipment on the market, such as air conditioners with HFC32, of which more than six million are already installed around the world.”

Ammonia Mania

With the many varying opinions from market experts, one can surmise that the search for the elusive refrigerant is still on.

With zero-ODP and zero-GWP ratings, ammonia is among the eco-friendliest refrigerants available. It is, however, also known for its toxicity, which is why the pros and cons of its use and application have long been debated.

At the 8th edition of The Climate Control Conference, held on June 15 and 16, 2015 in Dubai, UAE, Kandasamy Anbalagan, Managing Partner – Proleed Engineering Consultants, remarked: “We were wondering why people are not considering ammonia chillers in this part of the world [Middle East]. Basically, ammonia is considered as an industrial application, and it cannot be used in a commercial environment. But in places like Europe, it’s already in use, and they consider ammonia as a safe refrigerant. But you need to take care of a lot more aspects in terms of training the technicians and of how to manage an ammonia leak, if at all it happens.”

Suresh N Sharma, Regional Manager Industrial Refrigeration, Sales (MENA), at Danfoss, agrees that ammonia is quite safe, although he cautions that it is toxic. “However,” he adds, “if you see now the development that is going around the globe, we are having critical charge refrigeration systems, where the quantity of ammonia is gradually reducing. In fact, we have designed some systems where there are no receivers. So, there is no practical storage of refrigerants.” He says that such new systems are being developed to increase the efficiency of the use of natural refrigerants and the lifecycle of such equipment, which can go beyond 20 to 25 years.”

Talking about the advantages of ammonia and corroborating on its safety, Henrique Pereira, Managing Director at Seabra, goes on to list three distinct advantages of ammonia over other commonly used industrial refrigerants: “First, ammonia is environmentally compatible. Having an Ozone Depletion Potential (ODP) rating of 0 and a Global Warming Potential (GWP) rating of 0, ammonia does not deplete the ozone layer and does not contribute to global warming. Second, ammonia has superior thermodynamic qualities and, as a result of that, ammonia refrigeration systems use less electricity. Third, ammonia’s recognisable odour is its greatest safety asset. Unlike most other industrial refrigerants that have no odour, ammonia has a proven safety record, in part, because leaks are not likely to escape detection.” Sharma adds that ammonia is not easily inflammable. “If the heat level goes up to 600 degrees C, only then can ammonia catch fire, which will never happen,” he says. About the actual and future role of ammonia in the refrigeration industry, Pereira says that he completely shares Bruce Badger’s view. Badger, the President of International Institute of Ammonia Refrigeration (IIAR), asserts: “It may seem odd to call ammonia – a refrigerant first used for refrigeration in the 1800s – the refrigerant of the future. However, a drastic evolution in equipment, controls and other technologies in recent years is ensuring that ammonia will be at the centre of the new safer, greener and more efficient industrial refrigeration systems to come.”

The burning issue

Experts answer the question: are flammable refrigerants automatically unacceptable?

Dr Rajan Rajendran, Vice President of Systems Innovation Centre and Sustainability at Emerson Climate Technologies: “Flammable refrigerants are governed by safety standards that specify the charge amounts as well as other safety requirements. These standards often vary in different parts of the world, as well.”
Dr Veerle Beelaerts, Environment and Compliance Specialist at Daikin Middle East and Africa: “No, flammable refrigerants can be acceptable and applied safely depending on the application. For example, the flammable refrigerant, R600A has been used in home fridges since many years. It is useful to mention here that there are different types of flammability classes, as defined in the standard ISO5149: lower flammability (class 2L), flammable (class 2) and higher flammability (class 3). The potential application area for lower flammable refrigerants is, of course, broader than that for higher flammable refrigerants.”
Henrique Pereira, managing Director at Seabra: “Blended refrigerants that have flammable constituents are being used to mimic the performance of the common HCFC and HFC refrigerants, such as R22, R134A and R404A. These blends are marketed under various trade names and may have flammable constituents, or be themselves classified as flammable. Those refrigerants are mostly used in commercial refrigeration applications, with no common application in industrial refrigeration.”

The writer is the Features Writer of Climate Control Middle East.