Ali Koşar 

Sabanci University Nanotechnology and Applications Center (SUNUM), 

Center of Excellence for Functional Surfaces and Interfaces for Nanodiagnostics (EFSUN), 

Sabanci University, Istanbul, Turkey

E-mail: kosara@sabanciuniv.edu

Ali Koşar is a Distinguished Research Professor at Sabanci University.   He earned his master's and doctoral degrees in Mechanical Engineering from Rensselaer Polytechnic Institute.  He is focusing on the design and development of new generation micro heat sinks with functional surfaces and microfluidic devices including cavitation on chip devices. His research interests constitute a spectrum covering heat and fluid flow in micro/nano scale, condensation, boiling heat transfer, microfluidic systems, and cavitation. He co-authored over 150 research articles in top journals and 80 conference papers in prestigious international conferences. He has also a co-inventor on 7 granted patents and 7 pending patent applications. He received numerous national and international honors, including the µFIP Prominent Researcher Award" in the 2021 micro Flow and Interfacial Phenomena (µFIP) Conference, METU (Middle East Technical University) Prof. Mustafa N. Parlar Foundation Science Award (2021).  He is currently leading a large research group consisting of members from various disciplines, graduate students and engineers and to bridge different disciplines (Energy, Nanotechnology, Applied Physics, Bioengineering, Biochemistry, Mechanical Engineering). He has been successful to secure funding for his research activities from a wide variety of national and international resources.  He also serves as a reviewer in many prestigious journals and is a Subject Editor in the Applied Thermal Engineering journal. He is the Co-director of Center of Excellence for Functional Surfaces and Interfaces for Nano diagnostics (EFSUN) and a Distinguished Researcher of Sabanci University Nanotechnology and Application Center.  He was recently elected as a Member of Turkish Academy of Sciences (TÜBA). 

Title: New generation Biphilic Surfaces for Thermal-Fluids Systems and Energy Efficiency

Abstract：Boiling and droplet condensation are basic phase change phenomena and offer outstanding thermal performances.   Further heat transfer enhancements can be achieved with surface modification. As a result, many surface modification techniques have been proposed and investigated. One of the most promising approaches include the use of biphilic surfaces, which have mixed wettability (hydrophobic-hydrophilic, superhydrophobic-hydrophobic etc.) along the surface.  The optimization efforts for various biphilic surfaces in both boiling and dropwise condensation will be discussed in this talk.  With the optimum configurations of biphilic surfaces depending on the application and phase change phenomenon, it will then be possible to have significant energy saving and efficiency in thermal-fluids systems involving phase change.

The second part of the talk will focus on an effective and practical method for surface enhancement of thermal fluid systems via next generation bio-coatings based on hyperthermophilic archaea, which are durable, environmentally friendly, inexpensive, have unique structures and offer a porous biphilic surface or rough surface without the use of any cleanroom fabrication techniques.  The boiling heat transfer results of fundamental studies on bio-coated surfaces will be presented for both pool and flow boiling. In addition, the results on the implementation of these biocoatings to miniature air-conditioning  systems will be covered to prove the enhancements of the performances of  tested systems.  As a result, it will be shown that the very hard to achieve combination, namely higher heat transfer performance and energy efficiency without substantial pressure losses and minimized environmental effect, could be realized with next generation bio-coatings.