Exergy of nano-particulate materials
Unique behaviours and properties of nano-size materials make them very interesting for micro-as well as macro applications.Production processes of nano-particles may involve the use of significant amounts of complex chemicals.A more advanced approach,at least for the production of metallic nano-particulate(NP)materials may be the use of high voltage arc-or spark-driven systems.In addition to significant reduction in chemical use,the energy use of arcs/sparks exclusively in the form of electricity may be significantly less than the energy use allocated to waste stream processing from chemical usage,including handling and post-treatment needs in nano-tech industry.In this paper we asses,using exergy as a fundamental tool,energy efficiency for NP material fabrication and processing technologies.This subject is obscured by lack of data and the relatively meagre literature merging exergy and nano-technology in general.In fact,the subject matter of exergy of nano particles can be considered novel.Thus,the goal of this paper is to introduce a description of the exergy of NP materials and processes,opening a more extensive research on this important and emerging concept.Small particle size,cluster structure,and the high surface energy will have serious impacts on the results and will be addressed here.Simple metallic materials such as silver,gold,copper,nickel,zinc etc were taken as case studies.The results show that especially for NP material smaller than 20 nm the surface energy of the material becomes significant.Moreover,a large energy penalty results from the fact that temperatures and enthalpies of condensation and solidification are lower than values for melting and evaporation of the bulk material.Comparing theoretical values with first results from experiments shows that the specific electricity consumption is a few orders of magnitude higher than the energy penalties calculated as inevitable exergy losses.
Energy Efficiency Exergy Nano-particulate Materials Nano-processes
Ron Zevenhoven Asfaw Beyene
(A)bo Akademi University,Thermal and Flow Engineering,Turku,Finland San Diego State University,Department of Mechanical Engineering,San Diego CA,USA
国际会议
桂林
英文
1-9
2013-07-16（万方平台首次上网日期，不代表论文的发表时间）