Ammonia vs Synthetic Refrigerants: Which is Better for Cooling Systems?

As demand for reliable and efficient cooling continues to grow, selecting an appropriate refrigerant remains a critical decision for industrial refrigeration system owners and designers. This decision affects not only energy performance, but also safety, regulatory compliance, long-term availability, and operational risk.

In industrial applications, the discussion most often centers on ammonia (R-717) and various categories of synthetic refrigerants, with increasing attention given to newer low-GWP synthetic options, including A2L-classified refrigerants. Each option presents distinct advantages and constraints that must be evaluated in the context of system size, application, location, and regulatory environment.

This article outlines the key characteristics of ammonia and synthetic refrigerants as they relate to industrial and large-scale refrigeration systems, with an emphasis on accuracy, limitations, and practical considerations.

Ammonia as an Industrial Refrigerant

Ammonia (NH₃), designated as R-717, is a naturally occurring compound composed of nitrogen and hydrogen. It has been used in industrial refrigeration systems for well over a century, particularly in applications such as food processing, cold storage, beverage production, and other large-capacity facilities.

From an environmental classification standpoint, ammonia does not contain chlorine or fluorine and is therefore not associated with ozone depletion. It is widely recognized as having negligible direct global warming impact when released to the atmosphere, though environmental classifications may vary depending on the accounting framework used.

Ammonia is valued in industrial systems primarily for its thermodynamic properties, which allow it to perform effectively across a wide range of refrigeration temperatures when systems are properly designed and operated.

Safety Considerations

Ammonia is classified as toxic and mildly flammable under certain conditions. As a result, ammonia refrigeration systems require:

• Dedicated machinery rooms or controlled equipment spaces
• Fixed gas detection and alarm systems
• Emergency ventilation and pressure relief provisions
• Trained operating and maintenance personnel

These requirements are addressed through established codes, standards, and regulations. When properly designed, installed, and managed, ammonia systems are widely used in industrial environments where controlled access and trained staff are present.

Advantages Commonly Associated with Ammonia Systems

When applied in appropriate industrial settings, ammonia systems are often selected for the following reasons:

• Strong heat transfer characteristics, which can support efficient system designs
• Long-term refrigerant availability, with no phase-out schedules currently in place
• Distinct odor, which can aid in leak detection
• Suitability for large refrigeration capacities, where centralized systems are practical

It is important to note that these advantages depend heavily on system design, operating conditions, and maintenance practices, and should not be assumed universally across all installations.

Synthetic Refrigerants in Industrial and Commercial Systems

Synthetic refrigerants are manufactured chemical compounds developed to meet specific performance, safety, and compatibility goals. Over time, several categories of synthetic refrigerants have been used in refrigeration and air-conditioning systems.

Major Categories of Synthetic Refrigerants

• Chlorofluorocarbons (CFCs)
  Historically used but phased out due to ozone depletion.
• Hydrochlorofluorocarbons (HCFCs)
  Transitional refrigerants with reduced ozone impact, now largely phased out or restricted.
• Hydrofluorocarbons (HFCs)
  Zero ozone depletion potential but generally higher global warming potential.
• Hydrofluoroolefins (HFOs)
  Lower global warming potential than many HFCs, with different safety and chemical characteristics.

Synthetic refrigerants have historically been favored in applications where low toxicity, non-flammability, and compact system designs were priorities. However, regulatory pressure on higher-GWP refrigerants has introduced uncertainty regarding long-term availability for some synthetic options.

A2L Refrigerants: Lower-GWP Synthetic Options

A2L refrigerants are a subset of synthetic refrigerants classified as mildly flammable with lower global warming potential compared to many traditional HFCs. Examples include certain HFOs and HFO-based blends.

While A2L refrigerants are gaining adoption in HVAC and light commercial refrigeration, their applicability in industrial refrigeration systems is more limited and highly dependent on:

• Refrigerant charge size
• Occupancy classification
• Local code adoption
• Machinery room and ventilation requirements

As a result, A2L refrigerants are not universally interchangeable with ammonia or traditional industrial refrigerants, and their use must be evaluated on a project-specific basis.

Comparing Ammonia and Synthetic Refrigerants in Industrial Applications

Rather than framing refrigerant selection as “better” or “worse,” it is more accurate to compare risk profiles, system requirements, and regulatory implications.

Key Areas of Differentiation

Energy Performance
System efficiency depends on refrigerant properties and system design. Neither ammonia nor synthetic refrigerants guarantee superior performance without proper engineering.

Environmental Considerations

• Ammonia is not associated with ozone depletion and is widely regarded as having minimal direct global warming impact.
• Synthetic refrigerants vary significantly; some have zero ozone impact but higher global warming potential.

Safety Profile

• Ammonia presents toxicity risks that require engineered safeguards.
• Synthetic refrigerants may reduce toxicity risk but can introduce other concerns, such as flammability or difficult leak detection.

System Scale and Complexity

• Ammonia is commonly applied in large, centralized industrial systems.
• Synthetic refrigerants are often used in smaller or distributed systems, though this distinction is not absolute.

Regulatory Certainty
Refrigerant regulations vary by country and region. Some synthetic refrigerants face evolving restrictions, while ammonia has a long history of regulatory acceptance in industrial settings.

Regulatory and Industry Trends

Globally, refrigerant regulations are trending toward reduced environmental impact, particularly lower global warming potential. International agreements and regional regulations influence refrigerant availability, but their applicability depends on jurisdiction.

For industrial system owners, this reinforces the importance of:

• Understanding local and regional regulatory requirements
• Evaluating refrigerant choices over the full expected system lifespan
• Designing systems that can adapt to future compliance needs

Natural refrigerants, including ammonia and carbon dioxide, continue to receive attention in industrial refrigeration due to their regulatory stability and established performance in large-scale applications.

Choosing the Right Refrigerant

There is no single refrigerant that is universally appropriate for all refrigeration systems. Selecting the right option requires a project-specific evaluation that considers:

• Required cooling capacity and temperature range
• Facility layout and occupancy
• Available operational expertise
• Safety and risk management strategy
• Regulatory environment and long-term compliance outlook

In industrial refrigeration, ammonia remains a widely used and technically proven option when applied in facilities designed to manage its risks. Synthetic refrigerants continue to serve important roles in other applications, with newer formulations addressing environmental concerns while introducing new design considerations.

Making an Informed Refrigerant Decision for Your Facility

Refrigerant selection should always be based on engineering analysis, applicable codes, and documented system requirements, rather than generalized comparisons. Engaging experienced industrial refrigeration professionals early in the design process is essential to achieving safe, efficient, and compliant outcomes.