Prof.  Yan  Su
University of Macau,  China

Title: Multiscale Metal Foam Model for Convective Cooling of Photovoltaics

Abstract:

Metal foams are applied for cooling of solar photovoltaic for larger interface areas per unit volume and light weights. Heat transfer and fluid flow through metal foams are hard to be simulated due to the multiple length and time scales. Hence, a multiscale metal foam model is necessary to quantitatively study the cooling process of Photovoltaics using metal foams. The microscopic, mesoscopic, and macroscopic drag and heat transfer coefficients of metal foams are related with same sets of coefficients and geometry factors. Three scale drag coefficients, Nusselt numbers, and efficiency functions are expressed with varying structure properties and flow parameters. The general averaged microscopic scale drag and heat transfer coefficient constants can also be obtained by inversely correlated based on the pressure drop and fluid temperature change through the porous structures. Cross scale correlations are provided. Three-dimensional spiral flow structure cooling is compared with two-dimensional recirculation cooling. It is observed that larger local Reynolds numbers result in larger size spirals and the spirals appear at low local velocity zones behind solid phase materials with higher surrounding flushing local velocity. For spirals inside pores and behind the foam structures, the sizes are positively related to volume fractions of fluid and solid phases, respectively. Enhancement of cooling efficiency in solar photovoltaic systems are quantitatively compared for various types of porous structures including metal foams.

Biography:

Dr. Su is currently an associate Professor of Electromechanical Engineering in University of Macau. She received his PhD degree from the Department of Mechanical Engineering from University of Minnesota in 2006.  In year 2000 and 2003, she obtained her Bachelor of Thermal Engineering from Tsinghua University, and Master of Mechanical Engineering from Hong Kong University of Science and Technology, respectively. Dr. Su’s research interests include Thermal Dispersion in Porous Medium, Renewable Energy Systems, Oscillating Flows, and Indoor Air Quality. She also serves as the director of the solar energy laboratory of University of Macau and associate editors of Journal of Heat Transfer (ASME) and Case Studies in Thermal Engineering (Elsevier).