Low-GWP refrigerant

Definition

A low-GWP refrigerant is a refrigerant with a lower global warming potential than the higher-GWP refrigerants traditionally used in many refrigeration and air-conditioning systems.

Global warming potential, or GWP, measures how strongly a greenhouse gas contributes to global warming compared with carbon dioxide over a defined time period.

Low-GWP refrigerants can include hydrofluoroolefins (HFOs), HFO/HFC blends, hydrocarbons, carbon dioxide, ammonia, and other refrigerants with comparatively low climate impact.

There is no single universal GWP value that defines a refrigerant as low-GWP. The relevant threshold depends on the application, regulation, region, and equipment type.

Context

Refrigerants are essential to vapor-compression cooling systems because they absorb and release heat as they circulate through the refrigeration cycle.

If refrigerant escapes into the atmosphere through leakage, servicing, or equipment disposal, its global warming potential influences the resulting climate impact.

Many traditional hydrofluorocarbon refrigerants have relatively high GWP values. Environmental regulations and technology development are therefore driving the transition toward refrigerants with lower climate impact.

This transition affects refrigeration, air-conditioning, heat pumps, and other cooling systems across multiple industries.

For equipment manufacturers, refrigerant selection must balance environmental performance with cooling capacity, efficiency, operating pressure, safety, component compatibility, cost, and regulatory requirements.

Technical insight

Low-GWP refrigerants are not a single refrigerant family.

Different chemical families and refrigerant blends can provide lower global warming potential while having very different thermodynamic and safety characteristics.

Global warming potential

Global warming potential compares the warming effect of a greenhouse gas with that of carbon dioxide over a specified time horizon.

Carbon dioxide is assigned a GWP of 1.

A refrigerant with a GWP of 600 therefore has a significantly greater climate impact per unit mass released than a refrigerant with a GWP close to 1.

GWP values can also vary depending on the scientific assessment methodology used. When comparing refrigerants, the values should therefore come from the same reference framework.

HFO refrigerants

Hydrofluoroolefins are a newer class of fluorinated refrigerants developed in part to provide significantly lower global warming potential than many conventional HFC refrigerants.

Examples include R1234yf and R1234ze(E).

Many HFO refrigerants have very low GWP values because they break down relatively quickly in the atmosphere.

Some HFO refrigerants are classified as A2L, meaning they have lower toxicity and mild flammability.

HFO/HFC blends

Refrigerant blends can combine HFO and HFC components to balance environmental performance, thermodynamic properties, safety classification, and compatibility with cooling equipment.

Examples include R513A, R454B, and other lower-GWP blends.

These refrigerants can provide substantially lower GWP than older HFC refrigerants while maintaining characteristics suitable for particular refrigeration and air-conditioning applications.

However, the GWP and safety classification vary considerably between blends.

Natural refrigerants

Several naturally occurring or non-fluorinated substances can also be used as low-GWP refrigerants.

Examples include:

• Carbon dioxide
• Propane
• Ammonia

These refrigerants can provide very low global warming potential but introduce their own engineering considerations, such as operating pressure, flammability, toxicity, or system architecture.

Low GWP therefore does not automatically mean that one refrigerant is suitable for every application.

Safety classification

Refrigerant safety must be evaluated separately from global warming potential.

ASHRAE Standard 34 classifies refrigerants according to toxicity and flammability.

For example:

• A1 refrigerants have lower toxicity and no flame propagation under the specified test conditions.
• A2L refrigerants have lower toxicity and mild flammability with low burning velocity.
• A3 refrigerants are highly flammable.

As lower-GWP refrigerants become more common, system design increasingly needs to account for these different safety characteristics.

Refrigerant selection

Selecting a refrigerant involves considerably more than comparing GWP values.

Important considerations can include:

• Cooling capacity
• Operating pressure
• Energy efficiency
• Compressor compatibility
• Heat exchanger design
• Lubricant compatibility
• Refrigerant charge
• Flammability
• Toxicity
• Leak detection
• Service requirements
• Environmental regulations

The refrigerant and cooling system must therefore be evaluated together.

Key advantages

• Reduces the climate impact associated with refrigerant leakage
• Supports compliance with evolving environmental regulations
• Enables transition away from higher-GWP refrigerants
• Supports development of lower-impact cooling systems
• Provides multiple technology options across different cooling applications

Applications

Low-GWP refrigerants are increasingly relevant across cooling applications used throughout critical infrastructure.

Data center and IT infrastructure

Cooling systems supporting data center and IT infrastructure can use lower-GWP refrigerants as manufacturers develop air-conditioning equipment with reduced environmental impact.

Telecom and connectivity

Outdoor air conditioners used throughout telecom and connectivity infrastructure can use lower-GWP refrigerants to provide controlled cooling for network, power, and communications equipment.

Industrial automation

Cooling systems used in industrial automation can combine controlled enclosure temperatures with refrigerants designed to reduce the climate impact associated with potential leakage.

Energy and grid infrastructure

Air-conditioning equipment supporting energy and grid infrastructure can use lower-GWP refrigerants to provide thermal control for power electronics, controls, and communications equipment.

Oil, gas and mining

Cooling systems used across oil, gas and mining applications may also require refrigerants selected according to environmental regulations, operating conditions, and equipment safety requirements.

Defense and security

Cooling equipment supporting defense and security applications can use lower-GWP refrigerants where environmental performance, system reliability, and regulatory compliance must be considered together.

FAQ