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Automotive Refrigerant Design

Traditional auto air conditioning refrigerants have high global warming potentials, but finding better refrigerants with the right properties has been a major challenge for industry. Researchers at NIST provided measurements of refrigerant fluid properties that enabled the production and adoption of a next-generation auto refrigerant.

Rendering of a new Honeywell plant
Honeywell’s new R-1234yf plant in Geismar, Louisiana.
Credit: Honeywell

Traditional refrigerants used in vehicles have high global warming potentials—frequently thousands of times as potent as carbon dioxide—that can escape into the air. Because of this risk, the U.S. Environmental Protection Agency has worked to reduce the use of high global warming potential refrigerants in cars. In 2010, Honeywell, along with other members of industry, asked NIST to evaluate the thermodynamic properties of a newly developed refrigerant, R-1234yf, which has a global warming potential more than a thousand times lower than the current fluid.

NIST scientists provided the reliable measurement data necessary for the new, low global-warming-potential refrigerant to be adopted by industry. In addition to these measurements of thermodynamic properties, NIST provides equations that help engineers design equipment to use the new refrigerant. NIST includes this information in a Standard Reference Database, REFPROP, that makes fluid thermodynamic and transport properties available to customers worldwide.

NIST’s data and measurements efforts are an important step in putting new refrigerants into widespread use. R-1234yf is now being used in nearly 30 million cars worldwide, and Honeywell has created a major plant in Geismar, Louisiana, to increase its manufacturing capacity of the refrigerant.