VOICES | GRISHA GREBENNIKOV Alternative reality Engineers and manufacturers must take a proactive approach to breakdown the barriers to widescale adoption of low global warming potential refrigerants, says Mott MacDonalds Grisha Grebennikov A GRISHA GREBENNIKOV is a net zero carbon consultant at Mott MacDonald s an industry, we work with a multitude of systems that contain refrigerants and, in recent years, there has been growing concern about the part they play in global warming. Global warming potential (GWP) is a measure of how much a substance contributes to global warming over a specific timeframe compared with carbon dioxide (CO2). Higher GWP values indicate a stronger greenhouse effect. High-GWP substances such as hydrofluorocarbons (HFCs) and chlorofluorocarbons (CFCs) have been widely used in refrigeration and air conditioning systems, but are known to have a significant impact on climate change. A number of global regulations aim to phase out high-GWP refrigerants, including the European Unions F-Gas Regulation, which focuses on banning high-GWP KEY CONSIDERATIONS FOR LOW-GWP REFRIGERANTS Flammability: CFCs, HFCs and hydrochlorofluorocarbons (HCFCs) are considered non-flammable compared with some HFOs, ammonia, propane and isobutane, which have varying degrees of flammability. Toxicity: Varying degrees of toxicity for HFOs and ammonia, propane and isobutane require protective measures, such as suitable leak detection and enhanced storage precautions. CO2 is not considered toxic. Costs: HFOs tend to be more expensive (10 times more than HFCs) because of the current demand. Natural refrigerants are often less expensive than traditional refrigerants, but system costs may be higher because of the requirement for additional components and system adaptation. Adaptability with existing systems: HFOs are very versatile and can be used with HFC-based systems. However, natural refrigerants require substantial system modifications because of operational pressure, material compatibility and safety. Trained personnel: Engineers and technicians may require additional training and qualifications to operate with HFOs and natural refrigerants. Changes to regulation: Future regulations may focus on establishing stricter requirements for leak prevention, detection and disposal, and minimum energy efficiency standards on refrigeration equipment. Revised EU regulations are expected in early 2024. Impact of manufacturing: The production process for HFOs involves chemical synthesis that also produces carbon, which should be evaluated. Residual reactions: Ammonia is known to react with acidic compounds in the atmosphere and form particulate matter (PM 2.5), which has implications for air quality and human health. Furthermore, it can contribute to the formation of acid deposition (acid rain). Hydrocarbon-based refrigerants may undergo reactions to form photochemical smog (ozone). HFOs break down in the atmosphere to create high-GWP chemicals and produce TFA a persistent chemical. Ozone-depletion potential: As well as the GWP, ozone depletion potential needs to be considered (although it does not have a direct effect on global warming). HFCs, HFOs and natural refrigerants do not affect ozone depletion. 34 July 2023 www.cibsejournal.com refrigerants. From January 2025, there will be a ban on refrigerants with a GWP greater than 150. Furthermore, there is a HFC-specific target that aims to reduce its use by more than 80% by 2030. The recently introduced TM65: Embodied carbon in building services: a calculation methodology also considers the impact of refrigerants in the carbon lifecycle of HVAC building systems. There are a number of low-GWP alternatives available on the market, such as HFOs, CO2, ammonia and various hydrocarbon blends, which can act as direct replacements in existing and future refrigeration systems. They are not yet widely available, however, and there are key issues to consider (see panel, Key considerations for low-GWP refrigerants). To accelerate the delivery and acceptance of these alternative refrigerant and equipment manufacturers, industry associations must work together to develop common standards, share best practice, and foster innovation and research. HFO blends such as 448A and 449A can be used in systems as like-for-like replacements for HFCs. Natural refrigerants, such as CO2 and ammonia, may be more often used in larger commercial and industrial refrigeration and heat pump applications, while hydrocarbon-based refrigerants are more likely to be used for smaller domestic refrigeration and reversible heat pump systems. As the demand for alternative refrigerants increases, it is expected that the market position will improve, with more regulations forcing their uptake. For instance, HFO 1234yf, which is a popular variant for automotive air conditioning systems, could be used widely if regulations allow it. While the initial costs of HFOs and natural refrigerants may be higher compared with conventional refrigerants, long-term energy savings, regulatory compliance, and environmental benefits can offset these costs over the lifespan of the refrigeration systems. We know refrigerants with high GWP have a negative effect on global warming, and phasing them out will be key to meeting global net zero targets by 2050. For there to be a meaningful uptake of lower-GWP refrigerants across all sectors, it is incumbent on project teams to identify how this can be achieved and to realise the benefits of more environmentally friendly products for their scheme designs.