Refet Yalçin

• Engineering infrared opacifiers for insulation pads (fibrous, silicon based, and aerogel based) to avoid thermal runaway in electric vehicle batteries. Perform material level thermal simulations with COMSOL.
• Thermal modelization (radiation, convection and conduction) of paint drying & curing along with lamination material (PVB) in laminated glass and mirror lines that involves IR and convective heaters.
• Modeling and mitigating urban heat island effects, with a particular focus on radiative material properties. Heat transfer was studied in conjunction with computational fluid dynamics (CFD) in an urban canyon. A numerical model developed in ANSYS Fluent was validated using a physical canyon constructed in Sense-City at Université Gustave Eiffel.
• Radiative cooling material development, characterization and thermal / optical (spectral) measurements.
• Calculating buildings' energy consumption using Energy+ to identify the effect of material properties on energy consumption.
• Improving the thermal insulation of fibrous materials for cryogenic applications using a coupled conductive-radiative model and an inverse approach. Managing the outsourcing of thermal conductivity measurements at 20K.

• I authored the project proposal and successfully secured €197,000 in funding for a two-year period.
• Numerical design of nano-antennas to alter emission direction of the phosphor particles in semi-transparent greenhouse coatings to enhance photosynthesis thus plant growth.

• I authored the project proposal and successfully defended it during the interview.
• Solving dense medium radiative transfer in porous medium (i.e., silica aerogel). Validating the model by preparing colloids and aerogels followed by characterizing and measuring their thermal and optical characteristics.
• Solving absorption cross section of large photosynthetic cell ensembles (volvox). I leased and used a supercomputer from MS Azure with 3.6 TB of RAM to use the T-matrix method to solve a 60 micrometer sized volvox cell ensemble under visible light.
• Co-advising undergraduate and graduate students on dense medium radiative transfer projects (ongoing).

• Modeling and optimization of radiative cooling by using nano fibers. Analytical solution of scattering by a cylinder is used in conjunction with 3D Monte Carlo method to solve radiative transfer equation.
• Obtaining colorful radiative cooling coatings by using plain and core-shell nanoparticles, nano-layers and phosphor particles. Fabricating colored radiative coolers by sputtering silver NPs and measuring them in spectrophotometer.

Optical and thermal design of thin coatings made of thermochromic vanadium dioxide. Fabricating the coating with electron beam evaporation and annealing. Digitizing the SEM image of pigmented coating and solving EM wave interaction using discrete dipole approximation for large, effective medium theory for small particles, and validate the methods with spectroscopic ellipsometry data.

Research:

• Global optimization of solar thermal collectors' spectrally selective pigmented coatings by altering pigment size, concentration and coating thickness. Used methods: Metahuristic
  optimization, tabu search, simulated annealing, four-flux method, Mie scattering, the T-Matrix method.
• Improve of crops in greenhouses by altering the spectrum of sunlight using phosphor particles in greenhouse coating.

Teaching assistant of:

• Undergraduate Level: Computer applications in mechanical eng, thermodynamics I-II, heat transfer, design of thermal systems.
• Graduate Level: Advanced fluid dynamics, conduction heat transfer, convection heat transfer, radiative heat transfer.

Doctor of philosophy (PhD)
Improve of crops in greenhouses by altering the spectrum of sunlight using phosphor particles in greenhouse coating.

Master of science (MSc.)
Global optimization of solar thermal collectors' spectrally selective coatings by solving inverse problem.

Bachelor of science (B.Sc)
Thermodynamics, heat transfer, renewable energy.