By Eamonn Ryan
The refrigeration industry has long sought environmentally friendly solutions to replace harmful synthetic refrigerants.
While progress has been made in phasing out ozone-depleting substances, the focus has shifted to natural refrigerants—such as hydrocarbons, ammonia, and carbon dioxide—as sustainable alternatives with minimal global warming potential (GWP).
| Supplied by A-Gas
As South Africa approaches the final stages of the Montreal Protocol, the phaseout of hydrochlorofluorocarbons (HCFCs) is nearly complete. Since the start of the phasedown in 2013, many businesses in the Heating, Ventilation, Air Conditioning and Refrigeration (HVAC&R) industry have transitioned to using hydrofluorocarbons (HFCs). While these are not ozone-depleting, their high global warming potential (GWP) means that they too are subject to phasedowns over the coming decades. When making refrigerant choices during the current phaseout of HCFCs it is crucial to keep in mind that the Kigali Amendment to the Montreal Protocol (which was signed in 2019 and asks industries and governments to reduce the production and consumption of HFCs by 80% over the next 30 years) will take effect in 2029, beginning a mandated 10% reduction in HFC volumes based on the baseline years of 2020–22. South Africa’s Department of Forestry, Fisheries and the Environment (DFFE) continues to develop the national strategy for the phasing down of high- GWP refrigerants, but looking at global trends provides a likely blueprint. Countries that have already implemented similar transitions typically target high- GWP gases first.
Transitioning away from HCFCSSouth Africa has been phasing down HCFCs for the last 15 years at 5% per year as per the Gazette of 2014 and is now in the critical phase; a 30% reduction by the end of 2025. From 2026 there will be an import quota of only 2.5% until 2040. The need for the industry to transition to environmentally responsible alternatives is imperative. The current focus for the South African refrigerant industry is the phaseout of R22, which has been the refrigerant of choice for use in refrigeration, air conditioning and cooling systems for decades. The shift from HCFCs (like R22) raises several questions for stakeholders as they navigate the best refrigeration choices, such as:
The availability of R22 refrigerant is expected to diminish as manufacturers face restrictions, leading to a decrease in imports. Consequently, as demand rises and availability wanes, prices are likely to increase. Nevertheless, if effective Lifecycle Refrigerant Management (LRM) is implemented—specifically, the recovery and reclamation of R22 to meet AHRI specifications—R22 may remain accessible even after the quota reductions take effect.
Retrofitting with HFCs is an option. However, most drop-in replacements are blends, which introduce challenges such as glide, reduced performance and limitations on top-filling due to blend imbalances that reduce system efficiency. Multiple factors like oil type, compressor type, valves, performance impacts and retrofit system costs are all important considerations.
Installing systems that initially use R404A or R507 can be cost-effective in the short term, but these refrigerants are among the first targeted for phaseout under the Kigali agreement. A more future-proof solution is investing in equipment that is capable of handling next-generation refrigerants, for example, R448A (GWP 1494) and R449A (GWP 1504). These systems can later transition to even lower-GWP A2L refrigerants like R454A (GWP 270) or R454C (GWP 166) with minimal adjustments.
While natural refrigerants like R744 (CO₂) and hydrocarbons are the ultimate solution, one needs to consider the high initial costs, technical expertise requirements, high pressures, high running costs and flammability concerns.
Futureproof systemsInvesting in flexible systems allows businesses to align refrigerant use with Kigali phasedown requirements in mind and avoid frequent equipment reinvestments. Compressors designed to accommodate both current and future refrigerants ensure a smoother transition. By initially using R404A, R507, R448A or R449A, businesses can shift to blended refrigerants like R454A or R454C when Kigali regulations demand lower-GWP solutions and these refrigerants become readily available/more viable in Article 5 countries. However, those alternatives require meticulous system maintenance and commissioning. Leaks and improper handling can significantly impact performance, highlighting the need for robust upkeep protocols.
Key industry pathways
Maintain and retrofit Continue using R22 systems with R22 until the supply runs out or pricing becomes unaffordable to the end-user. Another option is retrofitting these systems with drop-in replacements to maximise the lifespan of existing equipment.
Install systems capable of handling a wide range of synthetic refrigerants and managing transitions in line with Kigali phasedown milestones.
Transition directly to natural refrigerants like hydrocarbons or R744, bypassing interim steps such as using HFCs.
Final thoughtsThe journey towards a low-GWP future is complex but essential for environmental and regulatory compliance. Industry stakeholders must weigh their options carefully, considering both immediate costs, long-term benefits and system implications*. By choosing the right pathway, South Africa’s HVAC&R sector can achieve a seamless transition while contributing to global efforts to mitigate climate change. By the conclusion of 2025, the R22 refrigerant market will undergo significant changes. Ultimately, any decision made during the transition will carry financial implications. During this phasedown, as in the previous transition away from CFCs, A-Gas offers a range of alternative refrigerants. *Please see the table below as to what considerations you need to take when deciding on the suitable alternative for your system. |
Natural refrigerants gain traction
Natural refrigerants have gained traction due to their low environmental impact and energy efficiency. Key developments include:
- Hydrocarbons (R-290, R-600a): Propane (R-290) and isobutane (R-600a) have become widely adopted in domestic and commercial refrigeration. R-600a dominates the domestic refrigerator market due to its safety and efficiency.
- Ammonia (R-717): A proven refrigerant in industrial applications, ammonia has seen a resurgence thanks to modern systems that minimise leakage risks.
Andy Pearson, Star Refrigeration. © Cold Link Africa - Carbon Dioxide (R-744): CO₂ has proven effective in commercial freezers and heat pumps, though its efficiency and cost remain challenges in some applications.
While natural refrigerants offer clear environmental benefits, their adoption involves trade-offs:
- Safety: Hydrocarbons are flammable, requiring stringent safety measures. Ammonia, though efficient, is toxic and requires careful handling.
- Efficiency: CO₂ systems can be less efficient than HFCs in high-ambient conditions, though advancements in transcritical CO₂ technology are improving performance.
- Cost: Initial investments in natural refrigerant systems can be higher, though long-term energy savings often offset these costs.
The future of refrigeration is poised for a significant shift toward natural refrigerants, as environmental regulations grow stricter and the demand for sustainable cooling solutions rises. This transition will likely unfold across several key sectors.
In industrial applications, ammonia and CO₂ are expected to remain the dominant choices for large-scale refrigeration, with ongoing innovations aimed at reducing charge sizes and enhancing safety measures. Meanwhile, the commercial refrigeration sector— particularly supermarkets—is increasingly adopting CO₂-based systems, including cascade and transcritical configurations, while propane gains traction in display cases due to its efficiency and lower environmental impact.
Heat pumps are another area of advancement, where CO₂ based systems show strong potential for high-temperature applications. However, ammonia and hydrocarbons continue to hold their own as viable alternatives, ensuring a competitive landscape as the industry evolves toward greener solutions.
Natural refrigerants represent a viable path toward sustainable cooling. While challenges remain—particularly in safety, efficiency, and cost—ongoing advancements and regulatory support will accelerate their adoption. As the industry moves away from fluorinated gases, natural refrigerants will play a pivotal role in reducing the environmental impact of refrigeration systems.
Reference:
- Dr Andy Pearson/Droetsi Memorial Lecture in Johannesburg
The potential of CO₂ in HVAC&R: a sustainable shift for the future
With a remarkably low Global WarmingPotential (GWP) of just one, CO₂ has emerged as a leading refrigerant in the cooling industry, offering a carbon footprint 1 774 times lower than conventional alternatives. While its adoption has gained momentum in refrigeration, the HVAC sector has been slower to embrace CO₂-based systems, often favouring refrigerants with higher GWPs. This hesitancy raises important questions—what barriers exist, and how can they be overcome to unlock CO₂’s full potential in HVAC?
One major hurdle is the difference in operational demands between refrigeration and HVAC systems. Refrigeration typically requires continuous operation, whereas HVAC systems face intermittent loads. Traditional CO₂ systems struggled to efficiently modulate output to match these fluctuating demands. However, recent advancements—such as high- tensile pressure components and auxiliary units—now allow CO₂ systems to maintain efficiency even during low-demand periods.
Energy efficiency has also been a concern, as CO₂ based systems historically lagged behind hydrofluorocarbon (HFC) alternatives in performance. But with innovations like advanced power conversion systems and parallel compression techniques, modern CO₂ HVAC systems are closing the gap—delivering substantial energy savings while drastically reducing carbon emissions.
Dispelling myths and highlighting benefits
Contrary to common misconceptions, well-designed CO₂ HVAC systems can achieve competitive energy efficiency. Even if they experience minor efficiency losses compared to traditional systems, their near-zero GWP makes them a far more sustainable choice. Given that the built environment contributes at least 40% of global carbon emissions, transitioning to low-impact refrigerants like CO₂ is no longer optional—it’s an urgent necessity.
Despite these advantages, conservative mindsets and a lack of familiarity with CO₂ technology remain barriers. HVAC technicians, unlike their refrigeration counterparts, often lack hands-on experience with CO₂ systems. Bridging this skills gap requires comprehensive training programmes and collaboration with engineering partners to ensure proper installation, commissioning, and maintenance.
Additionally, while upfront costs may be higher, the long-term environmental and operational benefits justify the investment. As global demand for air conditioning surges— along with concerns over refrigerant leaks and inefficient systems—the case for CO₂ HVAC grows stronger.
One of the most promising advancements in CO₂ HVAC technology is its ability to provide simultaneous heating and cooling without rigid load balancing. Unlike conventional systems, which require precise load matching, advanced CO₂ setups use intelligent software to dynamically adjust outputs based on real-time demand. This flexibility is particularly valuable in commercial and residential settings where heating and cooling needs fluctuate.
The transition to CO₂ HVAC is not just a technical shift—it’s a fundamental rethinking of sustainable building climate control. By leveraging proven refrigeration components, high-pressure adaptations, and smart energy management, CO₂ systems are proving they can compete with—and even surpass— traditional HVAC solutions in both performance and sustainability.
References:
- HC Group
- GEA
| GWP
The global warming potential (GWP) is a value that indicates the contribution to global warming. The GWP refers to the value of CO2 (GWP=1) as a benchmark. This means that a gas like R404A with its GWP of 3 922 contributes 3 922 times more to global warming than the same amount of CO2. Natural refrigerants have a GWP of 0 to 5.5. |
| ODP
The concept of the ozone depletion potential (ODP) is used as a measure of the effectiveness of a chemical compound in the degradation to the ozone layer it can cause, relative to the standard compound trichlorofluoromethane (R-11 or CFC- 11) being fixed at an ODP of 1. Natural refrigerants have an ODP of 0. |