Here is news of interest from research taking place at DOE’s Oak Ridge National Laboratory.
CO2 to the rescue
Tomorrow’s commercial refrigeration systems — like the ones in supermarkets – could be cooled by carbon dioxide instead of hydrofluorocarbons, a greenhouse gas that is nearly 4,000 times more potent than CO2. That is important because millions of pounds of HFCs leak into the environment every year, said Brian Fricke, a researcher in Oak Ridge National Laboratory’s Building Equipment Research Group. To address the problem, Fricke and colleagues are experimenting with CO2 and other refrigerants, including a hydrofluoroolefin called R1234yf. While by definition CO2 has a global warming potential of 1, the hydrofluoroolefin’s is 4, so both are far less harmful to the environment than HFCs with a rating of 3,900.
Still, while CO2-based systems work well in cold climates, they aren’t as efficient in warmer climates, so Fricke is experimenting with various approaches to address the limitation.
Low-cost 3-D feedstock
Reformulated plant matter could be at the roots of a revolution in 3-D printing projected to hit $5.2 billion by 2020. Soydan Ozcan, a researcher in Oak Ridge National Laboratory’s Carbon and Composite Group, leads a team that is testing plant material that has been reformed into neatly woven nanoscale crystals and fibers. Mixed with various plastics, including those that are bio-based, these needle-like crystals can produce feedstock polymers for 3-D printers with stiffness improvements already a factor of three over widely used structural materials. They are also less expensive and mostly biodegradable. Potential applications include fuel-efficient car parts, batteries, packaging and building materials, furniture, disposable electronics and bulletproof suits.
Better graphite anode
Lithium-ion batteries for cars, phones, laptop computers and other devices could retain their charge more effectively and last longer because of a method developed at Oak Ridge National Laboratory. By employing a proprietary additive to the furnace gas used during processing of natural graphite, the ORNL team produced anodes that enable a coin cell to retain up to 75 percent of its charge capacity after 1,600 to 2,000 cycles. This represents a significant improvement over the baseline version’s 67 percent after 1,400 cycles. Researchers noted that their patent-pending technique stabilizes the graphite surface, reduces cost and lowers temperature requirements. These advances allow processing to be done with less expensive furnaces and less energy. The method could also help the U.S. graphite industry gain a competitive edge over overseas sources. Findings were published in the journal CARBON.
Source: AAAS EurekAlert