Experts call for more natural refrigerant case studies

November 10, 2023

More high-quality, end user-focused case studies are needed to prove the business case for and support the adoption of natural refrigerants and new technologies, according to a group of HVAC&R industry experts.

With the necessary safety standards in place, the risks traditionally associated with natural refrigerants – such as the flammability of hydrocarbons, toxicity of ammonia (R717) and the high operating pressure of CO₂ (R744) – have been mitigated, according to independent engineering consultant Alexander Cohr Pachai, Chief of the Montreal Protocol Division at UNIDO Ole Reinholdt Nielsen and Technical University of Denmark (DTU) PhD student Martin Pihl Andersen.

However, one barrier that remains is a lack of “good case studies” that focus on the end-user experience, rather than the product or company sales efforts, they explained in their paper “Challenges of and Options for Refrigerant Selection.”

“From an end user perspective, the change to other working fluids gives no additional worries, because all standards are clear, and the insurance companies do not consider the risk to be higher than any other heating system if you follow the standards,” they said. “The worry can be more about the product and the procedures. As an example, if food production changes from boilers to heat pumps, will that affect the taste or the texture of the final product?”

Pachai, who has extensive experience in both commercial and industrial refrigeration, presented the paper at an Institute of Refrigeration (IoR) event in London on November 2.

Safety standards

As the world transitions away from f-gases – as required by international climate agreements like the Kigali Amendment, as well as national and regional policies like the EU F-gas Regulation – natural refrigerants offer stakeholders future-proof alternatives.

“Many different refrigerants are available, but it can be difficult to decide which is the most suitable for a particular application,” explained the authors of the paper. “Each refrigerant possesses its own set of strengths and weaknesses, [and] a refrigerant can be dismissed as being unsuitable due to one perceived hazard. However, it is still possible to use the refrigerant safely.”

For example, hydrocarbons’ flammability does not take them off the table as long as the applicable safety standards are followed correctly.

Such standards specify a range of actions needed to mitigate risks, such as charge limits, ventilation, air purification, enclosing refrigerant circuits, isolation of ignition sources and leak detectors.

Over the last few years, global standards pertaining to the use of flammable refrigerants like propane (R290) and isobutane (R600a) have recently been updated for commercial refrigerated cabinets and domestic air conditioners and heat pumps. As of September 2023, the new commercial refrigeration standards have become effective in the EU.

“Standards are in place and already being used by many manufacturers in the markets,” the authors added. “[However,] enforcement is key.”

Beyond the development of more case studies and the enforcement of safety standards, workforce capacity and training needs to be improved to support the safe adoption of natural refrigerants, they said. For example, the leak rate of a well-serviced ammonia compressor is often negligible.