Image by © RACA Journal Image by © RACA Journal www. refrigerationandaircon. co. za RACA Journal I August 2025 25
Feature
NATURAL REFRIGERANTS: A SUSTAINABLE COOLING SOLUTION
By Eamonn Ryan
The HVAC & R industry has long sought environmentally friendly solutions to replace harmful synthetic refrigerants.
While progress has been made in phasing out ozonedepleting substances, the focus has shifted to natural refrigerants— such as hydrocarbons, ammonia and carbon dioxide— as sustainable alternatives with minimal global warming potential( GWP).
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.
• 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 hightemperature 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.
Grant Laidlaw, owner of ACRA, at FRIGAIR
Christopher Visser, CEO of Multilayer Trading.
REFERENCE:
1. Dr Andy Pearson / Droetsi Memorial Lecture in Johannesburg
Image by © RACA Journal Image by © RACA Journal www. refrigerationandaircon. co. za RACA Journal I August 2025 25