Choosing A Natural Refrigerant

The shift to natural refrigerants is being driven by a mix of regulatory mandates, environmental responsibility, and long-term cost considerations. For HVACR contractors, understanding these three key forces is key to helping clients make informed, future-ready decisions:

• Regulations: Policies like the AIM Act in the U.S. and the European Union’s F-gas regulation are phasing down high-GWP synthetic refrigerants. Staying ahead of these changes is critical when designing or retrofitting systems.
• Environmental, social, and governance (ESG) concerns: More companies are aligning with sustainability goals and ESG standards. With near-zero GWP and no ozone-depletion potential, natural refrigerants like CO₂ and ammonia are better aligned with corporate climate commitments.
• Financial impact: Synthetic refrigerant systems may face rising costs or early obsolescence as regulations tighten. Natural refrigerants increasingly offer a lower total cost of ownership -- especially as technology improves and financial institutions favor climate-conscious investments.

When it comes to choosing the right natural refrigerant for a commercial or industrial refrigeration system, there’s no one-size-fits-all. Different applications require different refrigerants, but the most widely used options are carbon dioxide (CO₂) and ammonia (NH₃).

CO₂ is increasingly used in supermarkets and other commercial settings due to its efficiency in transcritical systems. However, its high operating pressure requires specialized system design and components. A key consideration for CO₂ systems – which sets them apart from other refrigerants -- is the need for high-pressure-rated components throughout.

To optimize performance, especially in high ambient conditions, CO₂ system designs often integrate parallel compression and, in some cases, ejectors to improve energy efficiency. The use of adiabatic gas coolers also plays a significant role in maintaining performance across varying climates. Additionally, smart control systems are highly recommended to enhance system reliability and ensure stable, efficient operation.

Ammonia is commonly used in industrial refrigeration because of its excellent thermodynamic properties and zero GWP. Safety measures must be in place to mitigate toxicity risks, particularly in populated areas. Best practices for ammonia systems include proper ventilation, gas detection and alarm systems, and designated containment areas. Machine rooms should be equipped with emergency exhaust systems, and all piping and equipment must be clearly marked and secured -- color coding is commonly used. Following IIAR, ASHRAE, and OSHA process safety management (PSM) standards is encouraged to ensure both safe and smooth operation.

In recent years, there’s been a growing trend toward low-charge ammonia systems and secondary loop systems to reduce the total amount of refrigerant on-site. Just as critically, proper personnel training in system operation, maintenance, and emergency procedures remain a cornerstone of safe ammonia use.

Understanding each refrigerant allows contractors to recommend the right solutions to their customers -- ones that balance energy efficiency, safety, and compliance with current and future regulations.

Supporting Customers

Many food retailers face the challenge of transitioning from legacy refrigeration systems designed for less sustainable synthetic refrigerants. While it may seem straightforward to retrofit outdated systems, the process often involves rethinking the entire refrigeration strategy -- not just swapping out the refrigerant. HVACR contractors play a critical role in evaluating and implementing solutions that minimize operational disruptions while ensuring long-term viability.

A recent retrofit project in Asia involved a decades-old cold storage facility originally designed for R-22 that was converted to a transcritical CO₂ system to comply with tightening environmental regulations and enhance energy efficiency. Due to the facility’s location in a coastal, high-humidity climate, careful consideration was given to equipment durability and thermal performance.

Components such as gas coolers with advanced corrosion-resistant coatings and high-efficiency fans were selected to ensure reliable operation in harsh conditions. The project demonstrates how natural refrigerants can be successfully integrated into existing infrastructure when supported by a thoughtful design and equipment strategy.

Businesses know that regulations are in flux, and they need solutions that balance compliance while also being cost-effective. Contractors who take a proactive approach will help clients navigate this shift with confidence. This approach may include:

• Conducting cost analysis: Helping clients understand long-term cost implications, including installation, maintenance, and energy savings;
• Providing regulatory guidance: Ensuring businesses remain informed and compliant with new regulations and standards;
• Tailoring system designs: Creating refrigeration solutions that meet the customer’s needs while optimizing performance, sustainability, and safety; and
• Educating clients for the long-term: Developing phased retrofit plans that minimize downtime and align with budgets.

The Future Is Here

Natural refrigerants are not just a trend -- they’re the future. As technology advances, they are becoming increasingly more competitive with synthetic alternatives in terms of cost, performance, and regulatory compliance. Many large-scale food retailers have already begun widespread adoption of CO₂ systems, leading the way in commercial facilities, while ammonia remains dominant in industrial cooling.

For HVACR contractors, the transition to natural refrigerants isn’t just about installing what works now, but about setting up systems that will remain viable for years to come. By staying informed on regulations, best practices, and new technological advances, contractors can position themselves as essential partners in the industry’s shift toward sustainable refrigeration solutions.