Kansas State University News Services 9 Anderson Hall, Manhattan, KS 66506-0117 (913) 532-6415; fax - (913) 532-6418
KSU Engineers Research Environmentally Safe Refrigerants MANHATTAN -- Production and consumption of R-22, the most widely used refrigerant in the United States, will be banned in the year 2020. Kansas State University is helping to prepare the United States, and countries such as Europe and Japan who rely heavily on R-22, for that cut-off point.
R-22, though better than older refrigerants such as R-12, has been found to have some adverse effects on the ozone layer. Steven Eckels, professor of mechanical engineering, is one of the researchers in K-State's College of Engineering who is studying six refrigerants that may be long-term replacements for R-22.
"Chemists come up with the refrigerants," Eckels said. "We take those and test how well they would work in real system components, like the components in central air-conditioning units in the home, air conditioners in cars, and refrigerators."
Eckels said some of the refrigerants they've been looking at -- R-134A, R-410A, and R-407C -- look to be the most likely substitutes for R-22 in many applications.
"Companies have indicated that if they had to switch right now, they'd pick one of these alternate refrigerants as a replacement for R-22," Eckels said. "R-134A is well-understood because it's currently being used in cars, but a lot of research is being done to better understand R-410A and R-407C."
K-State is also focusing much of their research on new parts that improve the performance of the condensers and evaporators, or the hot and the cold parts of air-conditioning units. One of the areas they are working on involves special tubes in the evaporators and condensers of the air-conditioning systems.
"We are evaluating tubes that are micro-finned, meaning they have small fins on the inside surface that seem to give us optimum performance," Eckels said. "The fins seem to make the heat exchanger operate more efficiently."
K-State is also studying the use of ammonia as a refrigerant. Refrigerants are given indexes on what their potential effect on global warming and ozone depletion are, and ammonia is the only one that appears not to cause either of these. Ammonia is toxic and flammable, but when used in systems designed with modern technology, it is a safe refrigerant to use.
Currently, K-State is one of only a few universities in the United States where facilities are available to study ammonia as a refrigerant. Donald Fenton, professor of mechanical engineering, is working closely with this research.
"Our research has two objectives," Fenton said. "We want to learn more about ammonia so it can be handled safely and its emission can be released properly. We also want to improve the performance of ammonia. Items like the enhanced micro-finned tube can improve its efficiency."
In addition to ammonia's environmentally friendly composition, the price of ammonia is relatively cheap, Fenton said.
"R-134A is expensive to purchase," Fenton said. "It costs from $3-4 per pound, while ammonia is 30 cents per pound. When you have a company that uses tons of refrigerants, ammonia's cost becomes appealing, but there may be greater expenses in safety measures."
Fenton said places that wish to use ammonia must not have any of the components of the refrigeration system containing ammonia in contact with the public. Ammonia systems would require the use of a nontoxic secondary fluid.
The ammonia refrigeration system would be located outside the building and would be used to chill this secondary fluid, located on the inside. This is so that if a leak should occur, there would be no ammonia released to the public.
Use of ammonia and other hydrocarbons, such as butane and propane, is a strong movement even though there are complications, Fenton said. Europe is already using them in many refrigeration applications.
The popularity of the hydrocarbons is that they are natural elements that are known not to harm the environment, Fenton said. He said that many people are afraid of the development of any new chemically based refrigerants.
"When the first refrigerants -- R-11, R-12, and R-13 -- were developed, they were thought of as extremely safe because they were absolutely benign in the chemical laboratories," Fenton said. "They were inflammable. Now, deep down, I think there are some concerns with the new chemicals being developed. People are afraid these may have some environmental implications we haven't thought of yet."
Prepared by Bree Bisnette. For more information contact Eckels or Fenton at (913) 532-5610.
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