Refrigerant Soup: CFCs, HFCs, HCFCs, etc.

The need to keep critical IT equipment cool is a fact of life in data centers to ensure efficient, always-on services. Unfortunately, the refrigerants used in traditional data center HVAC systems have high global warming potential (GWP), and they are being phased out in the U.S. The goal of the 2016 Kigali Amendment to the 1987 Montreal Protocol is to reduce emissions of hydrofluorocarbons (HFCs) by 80% over the next 30 years. How can data centers be responsible stewards of the environment and comply with this new directive while maintaining critical uptime?

The concentration of greenhouse gases in the Earth’s atmosphere has been rising due to factors directly related to human behaviors. And, it’s the increased concentration of gases that has raised the average temperatures on the planet. The refrigerants used in computer room air conditioner (CRAC) units play a part in this damage to the climate. Emissions of HFCs from HVAC units occur during the manufacturing process, leakage and service over the equipment’s lifetime, and disposal at the end of a unit’s useful life. In the environment, HFCs absorb and trap heat in the lower atmosphere and have a high GWP. HFCs typically have a GWP more than 1,000 times that of CO₂ .

With data centers on par with the aviation industry for their contribution to the world’s CO₂ emissions, alternative refrigerants in data center cooling systems have the potential to reduce emissions equivalent to 43.5 and 50.5 gigatons of carbon dioxide from 2020 to 2050.

The refrigerants used in air conditioning applications put a significant burden on the planet. The use of HFCs is a problem because the refrigerant is emitted to the environment — during production, due to leakage, and at the end of a unit’s life. It is estimated that 99% of gas refrigerants complete their life cycle in the atmosphere.

Because these emissions are so dangerous to the health of the planet, synthetic refrigerants are being phased out. Canada is on course to reduce HFCs by 85% by 2036. And, the U.S. has banned HFCs, including common refrigerants, such as R-134a, R-410A, and R-407C, from use in new chillers starting Jan. 1, 2024.

In the U.S., the Environmental Protection Agency’s (EPA's) Significant New Alternatives Policy (SNAP) has identified acceptable substitutes for air conditioning use that pose less overall risk to human health and the environment.  And one of those alternatives is CO₂, a natural, safe, and nonflammable gas, that has negligible GWP when used as a refrigerant.

HVAC equipment using CO₂ reduces the use of equipment with high GWP, thus contributing significantly to corporate environmental, social, and governance (ESG) initiatives and demonstrating a commitment to the environment. This proven technology has been used in Canada to cool data centers since 2012, and many U.S. companies are updating their cooling solutions to CO₂ systems ahead of the change in regulations.

In addition to being environmentally friendly and safe, CRAC systems using CO₂ as a refrigerant can save on energy and costs, improve system efficiency, and make better use of available space with the reduced size of the components. These sustainable and cost-effective systems are a possible solution to phasing out refrigerants with significant global warming potential, like hydrofluorocarbons, and now is the time to make the change.

Seth Chicos

Seth Chicos is the data center sales manager at Carnot Refrigeration.