Still Developing Environmentally Safer Refrigerants
DuPont, for example, has taken part in the search for alternatives from the beginning. The search for acceptable alternatives is not over, stated the Wilmington, DE, company, which is marking its 200th year in business this year.
Included on a DuPont team of scientists, researchers, and engineers is senior engineering associate Barbara Minor, who has spent more than half of her 20-year DuPont career investigating nearly every molecule involved in refrigeration in an effort to reconcile refrigerants’ benefits with their environmental impact.
The first chemical coolants, ammonia and sulfur dioxide, were toxic and flammable. By the middle of the 20th century, they were replaced by stable Freon® (a DuPont brand name); industrialized nations’ reliance on refrigerants grew significantly.
In the 1970s and 80s, scientists theorized and confirmed that CFCs quietly break down into chlorine molecules in the upper atmosphere. Chlorine depletes stratospheric ozone, which protects the earth from the sun’s ultraviolet radiation, according to many scientists.
Chemical manufacturers for the ACR market began developing non-ozone-depleting compounds, such as HFCs, and phasing out CFC-based products. Minor, a chemical engineer, transferred into the Fluorochemical Product Group in 1989, charged with developing better coolants on an accelerated timetable. She immediately joined other DuPont scientists in the hunt for molecules that might be the key to a stable, low-toxicity, and non-ozone-depleting refrigerant.
By the end of 1989, Minor and other DuPont researchers had filed 20 patents for HFC refrigerants. The company introduced its first formulations of Suva® HFCs in 1991. By the end of 1994, ahead of the CFC phaseout schedule set by the Montreal Protocol, DuPont was manufacturing eight blends of Suva for use in car air conditioners, supermarket display cases, and home and restaurant refrigerators. In 1995, the company commercialized additional blends for home air conditioners and heat pumps.
Today, Minor has about 45 U.S. patents for refrigerants to her credit, and she works on product development and support for major manufacturers, including Carrier, Lennox, Trane, and York.
“I remember the public concern when we began learning about the effect of CFCs on the ozone layer,” Minor said. “Now, because we’ve studied most possible molecules out there that could be refrigerants, I’m confident that we’ve developed the best products to fulfill society’s refrigeration needs.
“Every time I hear about this issue on the news, I feel good that I’m part of a global effort that will benefit the earth.”
Minor is chairman of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Immiscible Oil Refrigerant Systems Committee; a member of the Air-Conditioning and Refrigeration Institute (ARI) Working Fluids Committee; and serves on the International Standards Organization (ISO) technical assessment group that provides input to the United States’ position on refrigerants and the benefits they offer society.
Publication date: 09/02/2002