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Home » HFCs about to enter the start of the phase-down process

HFCs about to enter the start of the phase-down process

Compiled by Eamonn Ryan

Transcritical carbon dioxide (CO2) R744 refrigeration systems have gained wide acceptance in the supermarket refrigeration industry and there is some movement in the light commercial and other sectors of the industry.

Zayd Fredericks, industrial refrigerationrepresentative at Metraclark.
Zayd Fredericks, industrial refrigeration
representative at Metraclark. ©Cold Link Africa

According to GEA Heating & Refrigeration Technologies: “Ammonia is the most efficient and cost-effective natural refrigerant available today. It can generate 1.75kW out of 1m3/h mass flow. Because of its high capacity, less ammonia is needed for the equivalent output of alternative refrigerants. Ammonia (R717) was already in use back in the 19th century. With an ODP and GWP of zero, it is a particularly climate-friendly refrigerant and also a particularly efficient one. It has excellent thermodynamic properties, reflected in very low operating costs for refrigeration technology. It has consistently been used in food processing plants, the beverage and dairy industries, as well as in breweries and cold stores.

“The Coefficient of Performance (COP) of an ammonia-based heat pump running at typical conditions for a district heating network or for process heating below 100°C is for example up to 40% higher, compared to synthetic refrigerants, which means up to 40% lower emissions, up to 40% less energy usage and up to 40% lower cost. So, the use of ammonia reduces costs as well as emissions into the environment. Naturally these reduced production costs mean that margins increase for companies that switch to ammonia, as production becomes significantly more efficient.

“The inexhaustible supply of ammonia, and the fact that it has zero GWP also mean that refrigeration systems with ammonia are future-proof.”

Grant Laidlaw answers your questions

In South Africa, HFCs for example are about to enter the start of the phase down process. This will have a massive impact on our industry and in particular the air conditioning sector. Both R32 and R410a are HFCs and are to be phased down in accordance with the Kigali amendment of the Montreal Protocol. Although R32 has a GWP 32% lower than R410a the fact remains that R32’s GWP of 675 is above the cut off GWP of 500.

Grant Laidlaw, owner of Airconditoning and Refrigeration Academy (ACRA) says: “Given that CFCs are long gone, HCFC’s are being phased out, and HFCs are about to begin being phased down, where do we go? Naturals are the future, and the selection revolves around ammonia, hydrocarbons, some hydrofluoroolefin (HFO) refrigerants and carbon dioxide. I am aware of some research around using water (H2O) as a refrigerant – but we have yet to see commercially viable results.”

Technology advancements in CO2 systems are making these systems more economically viable, in terms of both equipment and installation costs but also energy and operating costs.

“Looking at some background information we find that CO2 is a naturally occurring compound in Earth’s atmosphere and it is the fourth most common atmospheric compound, behind nitrogen, oxygen and argon. As we all know carbon dioxide is an integral part of the life cycle of plant and animals, as the primary product of respiration in animals and humans. In turn, the carbon dioxide is absorbed by trees and converted back to oxygen.

“Through the process of photosynthesis, leaves draw in carbon dioxide and water and use sunlight to convert this into chemical compounds such as sugars that feed the tree. As a byproduct of that chemical reaction, oxygen is produced and released by the tree. It has been calculated that one large tree can provide oxygen for up to four people,” says Laidlaw.

“Trees also store carbon dioxide in their fibres, helping to clean the air and reduce the negative effects that this CO2 could have had on our environment. According to the Arbor Day Foundation, in one year a mature tree will absorb more than 48 pounds of carbon dioxide from the atmosphere and release oxygen in exchange.”

Carbon sinks: A carbon sink is anything that absorbs more carbon from the atmosphere than it releases – for example, plants, the ocean and soil. In contrast, a carbon source is anything that releases more carbon into the atmosphere than it absorbs – for example, the burning of fossil fuels or volcanic eruptions.

“In recent decades, carbon dioxide has been identified as the most significant greenhouse gas in Earth’s atmosphere. It is used as the comparative unit of measure when discussing the global warming impacts of various activities, leading to the term ‘carbon footprint’. CO2 as a refrigerant has emerged as one of the possible refrigerants of the future. It is environmentally friendly, has good heat transfer properties and a high latent heat of vapourisation. CO2 is also non-flammable and non-toxic with the refrigerant number R744.

“CO2 is commercially available at several different purity levels. The common names and percent purity recommended for refrigeration systems using CO2 with a purity equal to or greater than Bone Dry Purity.”

Examples of various grades of CO2 are shown below:

  • Industrial Grade – 99.5%
  • Bone-Dry Grade – 99.8%
  • Anaerobic Grade – 99.9%
  • Instrument Grade – 99.99%
  • Research Grade – 99.999%
  • Ultra-Pure Grade – 99.9999%

    Presenter Werner Terblanche of A-Gas South Africa describing the Kigali Amendment to the MontrealProtocol phase-out and phase-down regulations
    Presenter Werner Terblanche of A-Gas South Africa describing the Kigali Amendment to the Montreal Protocol phase-out and phase-down regulations. ©Cold Link Africa

He lists key factors to note as follows:

CO2 used in commercial refrigeration systems must be of a purity level high enough to prevent the introduction of non-condensable gases into the system.

A build-up of these gases can block the heat transfer surface and cause inefficient operation or malfunction of the system.

“Mixing of higher purity grades of CO2 is acceptable. Lower grades of CO2 will be less expensive but are not recommended. In addition to non-condensable gases, these lower grades contain higher levels of contaminants and water. Higher levels of moisture may react with the CO2 and form carboxylic acid that can degrade system component integrity.

Carbon dioxide as a refrigerant has an extremely low carbon footprint, compared to common synthetic refrigerants. The absence of ODP and extremely low GWP make CO2 attractive as a refrigerant from an environmental perspective.”

Laidlaw adds: “Unfortunately the primary disadvantages of CO2 as a refrigerant are the relatively high operating pressures and fairly complex refrigeration systems. Oil management needs particular attention.

“Let us have a look at a transcritical system. A transcritical system is defined as a system that operates above the critical point. Above this point, the refrigerant is not considered liquid or gas, but an undefined fluid. This can be seen on a Mollier diagram. Fluorinated refrigerant systems operate below the critical point. In the case of CO2 systems this temperature is often exceeded when ambient air is used for condensing.

Critical point on a Mollier diagram.
Critical point on a Mollier diagram. Supplied by Grant Laidlaw

Safety when using CO2

The physical properties of CO2 present a unique set of considerations to ensure safety. CO2 is classified as an A1 refrigerant by ASHRAE 34 meaning it is non-toxic and non-flammable. However, like many refrigerants currently in use, a large enough leak in a confined space can displace available oxygen for breathing.

At typical refrigeration temperatures, CO2 operates at considerably higher pressures than synthetic refrigerants – up to around 10 500kPa but 14 000kPa is possible in some instances. When released at these pressures to the atmosphere, CO2 can change phase to solid form, causing restrictions in the flow that can lead to a buildup in pressure. The concern remains that a large leak of CO2 can displace existing air in a space, reducing the oxygen levels. If the oxygen levels are reduced considerably, this can lead to health hazards up to and including asphyxiation/death. Average outdoor air consists of around 400 parts per million (0.04%) of CO2. The details below list some additional concentration levels and the effects on the human body.


0.1%–0.2%: Breathing rate increases slightly.

0.3%: Breathing rate increases to 50% above normal level. Exposure can cause headaches, tiredness, weak narcotic effect, impaired hearing, and increased blood pressure and pulse rate.

0.5%–1%: Characteristic sharp odour noticeable. Breathing increases to approximately four times normal rate and can be very laboured. Symptoms of intoxication become evident, and slight choking may occur. Visual impairment, headache, and ringing in the ears. Judgment may be impaired, followed within minutes by loss of consciousness.

Unconsciousness occurs more rapidly above 1% level. Prolonged exposure to high concentrations may eventually result in death from asphyxiation.

“Perhaps we should at this point note that as CO2 at ambient pressure is heavier than air, leak detection systems should be placed low, approximately 200mm from the floor. Let us have a look at the pressures expected when using CO2 as a refrigerant. We know that CO2 operates at higher pressures than typical HCFCs or HFCs, due to the inherent thermodynamic properties of the substances. HFC direct expansion (DX) refrigeration systems mechanical safeties and control set points shut the system down around 2 400kPa (depending on the refrigerant) discharge pressure. The entire piping system is rated for safe working conditions above this maximum pressure, so no secondary relief devices are necessary.

“In addition, if the fluorinated refrigeration system shuts down due to power outage or servicing, the internal pressures do not climb any higher to exceed the maximum system design pressure. In fact, the pressure tends to fall as temperatures drop and equalisation occurs.

“In the case of CO2, the high saturated pressure of CO2 at summertime ambient conditions exceeds the pressure rating of type K copper piping, along with most standard DX refrigeration valves. This requires the “high side” of the CO2 system to be constructed using higher pressure rated materials and installation practices, at a higher cost.

A rapt audience at the April SAIRAC Johannesburg Tech Talk hosted at ACRA
A rapt audience at the April SAIRAC Johannesburg Tech Talk hosted at ACRA. ©Cold Link Africa

“To reduce overall system installation cost, the ‘low side’ portions of a CO2 system are designed for the lower operating pressures, allowing copper to be used for the low side piping. When the system is operating normally, pressures are maintained below the rated pressure of the system. The CO2 system pressure becomes a safety concern when liquid becomes trapped in a portion of the system that is not rated for the full pressure at higher temperature,” he says.

“It is therefore critical not to allow liquid CO2 to become trapped in the system without means of pressure relief. As the temperature of a saturated mixture rises, pressure will rise until it reaches the saturation pressure in the table above. If the refrigerant pressure exceeds the rating of the piping, valves, or other components of the system, this can lead to leaks and possibly bursting of system components.

“Measures must be taken in system design to ensure that pressure cannot build up in any portion of the system. All components, valves, piping, fittings and joining methods are to be verified to ensure pressure ratings above the maximum anticipated system pressures.

“On CO2 systems, pressure relief devices must be appropriately located to allow the system to vent safely in the event of a system shutdown or other event that causes pressures above system ratings. All points within the system must be allowed to vent back to the pressure relief valves without restriction. Check valves are typically utilised to allow portions of the system to vent back to receivers, where pressure relief valves are located. Any portion of the system that cannot vent back to the receiver must have its own pressure relief valve.”

Laidlaw highlights a particular issue with CO2 as being the formation of dry ice, which is simply CO2 in solid form. In a CO2 refrigeration system, there are two common conditions where this may occur.

The first and potentially dangerous location is at a pressure relief valve. When a pressure relief valve is open, the refrigerant is undergoing a rapid drop in pressure from system pressure to atmospheric pressure. If liquid CO2 is being released, the CO2 release in a solid and vapour mixture causes the formation of dry ice. Therefore, pressure relief valves should not have any piping installed downstream of the valve. If the pressure drop happens inside the pipe, dry ice will form, blocking flow and preventing pressure from being released.

The second condition where dry ice may form is when charging the system. If the system vacuum is broken with liquid, dry ice can form inside the system, again restricting flow. This condition is less dangerous because it does not cause pressure buildup beyond system ratings but should still be avoided.


Ammonia usage in commercial cold stores is increasing

In recent years, there has been a noticeable surge in the utilisation of ammonia as a refrigerant across various industries. Notably, ammonia emerges as a cost-effective alternative, particularly for larger capacity cooling applications, owing to its lower operational expenses, says Zayd Fredericks, industrial refrigeration representative at Metraclark.

He explains that Metraclark has witnessed a significant increase in demand for ammonia-related equipment. According to Fredericks, this uptick in demand aligns with the growing need for efficient refrigeration solutions, especially among companies involved in cold storage, logistics, breweries, poultry and retail distribution centres.

The reason for choosing ammonia system cooling solutions can be attributed to its cost-efficiency, especially in the face of rising energy costs. Unlike traditional refrigerants like Freon, which may have lower initial capital costs but higher operational expenses, the running costs associated with ammonia are substantially lower. This cost advantage makes it an attractive option for businesses seeking to optimise their operational expenditures in the long term.

“Despite the higher initial investment required for installing ammonia-based systems, the potential for long-term savings outweighs this drawback for many businesses. While consulting engineers often face challenges in convincing clients to invest in equipment upgrades due to concerns over upfront costs, the cost-effectiveness of ammonia presents a compelling case for consideration,” he adds.

The trend towards increased adoption of ammonia as a refrigerant is not limited to a specific industry or geographic region, says Fredericks. “This growth trajectory is expected to continue, driven primarily by the economic benefits and operational efficiencies offered by this natural refrigerant.”

Beyond mere sales, Fredericks emphasises understanding the benefits of ammonia, particularly in long-term operational efficiency. According to their observations, major cold storage players are strategic in their decision-making processes, indicating that the shift towards ammonia is not impulsive but rather a carefully planned endeavour.

The rationale behind this strategic shift varies across different sectors. While food security emerges as a primary concern for cold storage facilities, breweries and dairies, the beverage industry operates on a more predictable growth trajectory driven by consumer demand. This dichotomy underscores the importance of cultural and economic factors in shaping industry preferences.

Despite limited information on specific projects, anecdotal evidence suggests a notable uptick in interest, potentially fuelled by legislative changes such as those in the EU mandating lower storage temperatures for perishable goods, as well as phase-down regulations in terms of the Kigali Amendment favouring natural refrigerants.

Furthermore, the expansion of refrigeration capacity, particularly in sectors like citrus production, highlights the broader economic implications of refrigeration trends. While some businesses focus on survival amid market challenges, others capitalise on growth opportunities, leading to a dynamic landscape of industry players.

The geographical distribution of refrigeration projects also reflects the diversity of the market. For instance, while Cape Town may be a hub for certain fruits, the Eastern Cape emerges as a prominent location for ice cream production, catering not only to local demand but also to international markets.

Fredericks concludes that the increased usage of ammonia as a refrigerant signifies a strategic response to evolving market dynamics, driven by a combination of economic, regulatory and operational factors. “As industries continue to prioritise efficiency and sustainability, the role of ammonia in refrigeration is expected to expand further, shaping the future of cold chain logistics and food security initiatives both locally and globally.”


Climate change and challenges for the HVACR Industry

SAIRAC Johannesburg President, Robert Fox, delivered the following presentation in a previous Tech Talk, addressing the crucial topic of ‘Climate Change and Challenges for the HVACR Industry’.

In the early 1970s, scientists at NASA made a noteworthy observation of peculiar ozone readings over the Arctic region. Subsequent research led them to publish a study proposing the existence of an ozone hole, which was met with general scepticism. However, by 1980, as the ozone hole expanded, it garnered global attention and sparked further investigations. This turning point gave rise to the Vienna Convention, which aimed to tackle ozone depletion, and culminated in the Montreal Protocol of 1987.

The Montreal Protocol galvanised international commitment to reduce the use of chlorofluorocarbon (CFC) refrigerants. The ozone hole continued to expand until the year 2000, exacerbated by shifting weather patterns. Only in 2015 did the expansion cease, with a reduction of 20%, thanks to concerted efforts. Subsequently, the Kigali Amendment emerged, focusing on the global warming potential (GWP) and necessitating the phased elimination of hydrochlorofluorocarbons (HCFCs) and phase down of hydrofluorocarbons (HFCs). South Africa ratified this amendment in 2019.

SAIRAC Johannesburg President, Robert Fox, delivered a presentation in a previous Tech Talk,addressing the crucial topic of ‘Climate Change and Challenges for the HVACR Industry’.
SAIRAC Johannesburg President, Robert Fox, delivered a presentation in a previous Tech Talk,
addressing the crucial topic of ‘Climate Change and Challenges for the HVACR Industry’. ©Cold Link Africa

Our journey in refrigeration dates back to the 1830s when natural refrigerants were first employed. Subsequently in the 1930s, R12 – a synthetic refrigerant known for its affordability and safety – was invented. The period between 1950 and the discovery of ozone depletion witnessed the prevalent use of CFCs, followed by HCFCs, with R22 being the most common variant.

In response to the depletion of the ozone layer, the industry transitioned to HFCs. However, in 2015, the European Union initiated a phase-down of HFCs to achieve a GWP below 150, thereby redirecting the market towards natural refrigerants. Examples of such environmentally favourable alternatives include ammonia, CO2, and hydrocarbons such as R600 and R290. The Kigali Amendment specifically outlines the phasedown of HFCs.

To comprehensively understand the measures taken to address refrigerant emissions, it is essential to familiarise ourselves with several significant global treaties:

Montreal Protocol on Substances that Deplete the Ozone Layer (1987): The Montreal Protocol is an international environmental treaty aimed at protecting the ozone layer by phasing out the production and consumption of ozone-depleting substances (ODS), including CFCs and HCFCs. It sets specific reduction targets and schedules for the phase-out of these substances, leading to the recovery of the ozone layer.

Copenhagen Amendment to the Montreal Protocol (1992): This protocol aimed to accelerate the phase-out of CFCs and HCFCs.

Kyoto Protocol to the United Nations Framework Convention on Climate Change (1997): It established binding emission reduction targets for several greenhouse gases, including HFCs, by setting specific emissions limits for developed countries during the first commitment period (2008–12).

Beijing Amendment to the Montreal Protocol (1999): This established a fund, the Multilateral Fund for the Implementation of the Montreal Protocol, to assist developing countries financially and technologically.

Kigali Amendment to the Montreal Protocol (2016): It specifically addresses the phasedown of HFCs, setting targets and schedules for reducing the production and consumption of HFCs, which are potent greenhouse gases used as substitutes for CFCs and HCFCs. The amendment aims to avoid up to 0.5°C of global warming by the end of the century and provides a framework for transitioning to more environmentally friendly alternatives.

These treaties have encouraged the development and use of alternatives that have lower or no impact on the ozone layer and contribute less to climate change.

Commencing in 2024, South Africa embarks on the phasedown of HFCs with a gradual reduction in the volume of imported refrigerants. Consequently, if the current import stands at 100 tons, the new limit will be 90 tons. However, this transition cannot occur overnight due to the considerable lifespan of installed refrigerant systems, which typically spans 20 years.

The phasedown process is anticipated to be a gradual and protracted transition, and significant changes are not expected in the immediate two to three years. However, we have begun observing the emergence of air-conditioning systems utilising R32, a refrigerant boasting a superior GWP of less than 750. While this presents a more favourable option, it is essential for technicians to undergo training in handling the new refrigerants and be aware of their inherent hazards when not handled properly. In the long run, natural refrigerants represent the optimal choice; unfortunately, the necessary hardware is not always available within the country.

Regulatory requirements play a critical role in guiding the industry towards sustainable practices. However, there have been notable delays in governmental decision-making processes. For instance, despite the Kigali Amendment being introduced in 2016, South Africa ratified it only three years later. Currently, the country relies primarily on outdated standard environmental acts as the sole government regulations. In 2012, the HCFC phase-out national plan was introduced, followed by the publication of the National Environment Management Air Quality Act in 2014, which specifically addressed the phase-out and management of ozone-depleting substances. South Africa’s ratification of the Kigali Amendment occurred in 2019. In 2021, an amendment was published; however, it failed to provide substantial guidance on the future phasedown in accordance with the Kigali Amendment. Consequently, a pervasive sense of uncertainty prevails, and a comprehensive roadmap for transitioning towards natural refrigerants remains absent.

Although hydrocarbon refrigeration technology is already established in other parts of the world, it is not yet fully commercially available within South Africa and is currently limited to the domestic appliance market segment. Importation of such technology is currently limited due to the lack of demand within the country.

The complexity escalates when considering multiplex systems employing ammonia and CO2. Furthermore, analysing the cost of refrigerants relative to the baseline R22, R404 demonstrates a substantial increase of approximately 1.7 times, while the new refrigerant 448 is nearly 3.3 times more expensive than R22. Conversely, R290 proves to be a more affordable alternative to R22; however, its viability is hindered by the unavailability of compatible hardware.

The ideal refrigeration system.
The ideal refrigeration system. Supplied by Rob Fox

Addressing maintenance costs, fuel quality, pressure and flammability requires adherence to safety principles outlined in SANS 10147 and ASHRAE Standard 34, which categorise refrigerants into different safety groups.

Regardless of the safety group classification, be it A1 or A3, utmost importance must be placed on ensuring proper handling to mitigate potential risks. Technicians operating in the industry must prioritise the critical aspect of refrigerant training. Alarmingly, a significant number of technicians remain unregistered and lack adequate training. It is imperative to drum home the necessity of attending training programmes to enable safe handling of refrigerants. This presents a formidable challenge that must be urgently addressed.


  • GEA LinkedIn
  • SETA training
  • ACRA
  • A-Gas
  • Hussman Training
  • Arbor Day Foundation
  • Cold Link Africa contributor Andrew Perks
  • Various SAIRAC Johannesburg Tech Talks attended by Cold Link Africa
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