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July 2008
BFRL Monthly Highlights
March 2008 April 2008 May 2008 June 2008 July 2008 MORE Highlights
Diamond Nanoparticles are a Chiller’s Best Friend
Tinkerbell’s pixie dust may no longer have the market cornered as far as magical nanoparticles are concerned. BFRL’s Mark Kedzierski is finding this out first hand with his investigations into the effect of nanolubricants on refrigerant boiling. One nanolubricant—a lubricant for chillers with dispersed nanosize particles—has resulted in an approximately 275 percent improvement in the boiling heat flux as compared to refrigerant/lubricant boiling without nanoparticles. This obviously shows great potential for energy savings in chillers that keep the occupants of large buildings cool. But as with all good things, it isn’t foolproof. In fact, adding an insufficient amount or the wrong type of particles might lead to a degradation in performance. That’s why BFRL has undertaken a study to discover what and how much nanoparticles provide the best improvement in boiling heat. So far, nanoparticles made of copper oxide are found to provide significant improvement if a critical mass of nanoparticles is present. In other words, there have to be enough particles left over after filling nanosize cavities on the boiling surface to cause boiling enhancement. Preliminary results show that diamond nanoparticles can also significantly benefit refrigerant/lubricant boiling heat transfer but require a smaller concentration than copper oxide to do so. Unraveling the mysteries of how nanoparticles can be used in chillers to save energy could have a large impact for electricity consumption associated with buildings, which currently consume 72 percent of the Nation’s electricity. In the present climate of escalating gas prices, saving energy would be a welcomed bit of magic.
CONTACT:
Mark Kedzierski
301-975-5282BFRL’s Domanski Elected ASHRAE Fellow
Piotr Domanski of BFRL’s Building Environment Division has been elected fellow of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). This award, which recognizes distinction in the arts and sciences of environmental technology, is based on Domanski’s contributions benefiting the refrigeration, air-conditioning industry. Domanski was cited for his research on stratospheric ozone-safe refrigerants, modeling work on vapor-compression systems, and development of rating procedures used by industry.
CONTACT:
Piotr Domanski
301-975-5877Six Translations of An Article
In February 2008, the Journal of St. Petersburg State Academy of Refrigerating and Food Technologies published a Russian translation of the article “R22 Replacement Status,” authored by J.M. Calm (engineering consultant) and Piotr Domanski (BFRL). The Russian translation followed previous publications in foreign journals in Spanish, Italian, Polish, Portuguese, and Chinese, and its republication in English in Australia. R-22, the most widely used refrigerant, is being phased out because of its stratospheric ozone depletion potential. In the article, originally published in the ASHRAE Journal [46(8):29-39, August 2004], the authors discuss alternative refrigerants and technical issues related to R22 replacement.
CONTACT:
Piotr Domanski
301-975-5877
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Last updated: 7/10/2008