Investigation of Nanostructured Surfaces for Thermophotovoltaic Applications

Atak, Eslem Enis
Thermophotovoltaic (TPV) devices convert thermal radiation into electricity by using a thermal emitter and a photovoltaic (PV) cell. TPV systems can utilize variety of heat sources, which makes them suitable for harvesting waste heat. The downside of current TPV technology is its low efficiency due to the spectral mismatch between thermal emission of the emitter and the bandgap of the cell. In this thesis, the effect of nanostructures on radiative properties is studied in order to develop efficient TPV emitters and cells. Accordingly, metal-insulator-metal (MIM) nanostructured TPV emitters to match GaSb and Si cells were designed and optimized in order to achieve high power output and efficiency, by using finite-difference time-domain (FDTD) and particle swarm optimization (PSO) methods. In addition, nanostructured Si cells were developed to increase useful absorption without cell heating, by FDTD and parameter sweep methods. At 1700 K, W-SiO2-W emitter showed an efficiency of 22.73% and power output of 3.622 W∙cm-2, which is 177% more efficient and produces 9.7% more power than SiC emitter paired with GaSb. At 2000 K, Ta-HfO2-Ta emitter demonstrated an efficiency of 27.91% and power output of 4.755 W∙cm-2, which is 53.3% more efficient while producing 87.4% more power than Yb2O3 emitter paired with Si. In nanostructured Si cells, useful radiation increased by 30.4% while limiting thermalization increase to 24.4%, compared to flat Si cell, when illuminated by a blackbody at 2000 K. The results of this work are expected to shed a light onto the potential of developing high efficiency TPV systems.


HİÇDURMAZ, SERDAR; Tarı, İlker (Begell House, 2018-01-01)
A thermal energy storage unit designed to be used in a solid particle concentrated solar energy system is analyzed with the help of ANSYS Fluent 17.0. Hydrodynamics of the bubbling fluidized sand bed of 0.28 m × 1 m × 0.025 m dimensions to be used as a direct contact heat exchanger is modeled and validated. Geldart B-type particles with diameter of 275 micrometers and density of 2500 kg/m3 are used in modeling of bubbling fluidized sand bed. A Syamlal−O'Brien drag model with restitution coefficient of 0.99 ...
Investigation of various options for numerical modeling of fluidized bedsI for a solar thermal application
Bilyaz, Serhat; Tarı, İlker (null; 2015-05-29)
Circulating fluidized bed solid particle absorption solar thermal energy system is a promising approach to solar thermal with thermal energy storage. For accurately modeling such systems, the fluidized bed numerical model should be correctly representing the behavior of the actual bed. There are several suggested partial semi-empirical models in the literature considering distinct phenomena related to fluidization and void fraction distribution in a fluidized be...
Proposal of a Novel Gravity-Fed, Particle-Filled Solar Receiver
JOHNSON, Evan; Baker, Derek Keıth; Tarı, İlker (2016-10-14)
Solar Thermal Electricity power plants utilizing solid particles as heat transfer and storage media have been proposed by several research groups, with studies citing benefits of increased thermal efficiency and lower cost. Several types of solid particle receivers have been proposed, with leading designs consisting of particles falling or suspended in air. A new solid particle receiver is proposed here, consisting of a receiver fully packed with particles flowing downward with gravity. Particle flow rate i...
Near-field radiative transfer in spectrally tunable double-layer phonon-polaritonic metamaterials
Didari, Azadeh; Elçioğlu, Elif Begüm; Okutucu Özyurt, Hanife Tuba; Mengüç, M. Pinar (Elsevier BV, 2018-6)
Understanding of near-field radiative transfer is crucial for many advanced applications such as nanoscale energy harvesting, nano-manufacturing, thermal imaging, and radiative cooling. Near-field radiative transfer has been shown to be dependent on the material and morphological characteristics of systems, the gap distances between structures, and their temperatures. Surface interactions of phononic materials in close proximity of each other has led to promising results for novel near-field radiative trans...
Development of view factor correlations for modeling thermal radiation in solid particle solar receivers using CFD-DEM
Johnson, Evan; Baker, Derek Keıth; Tarı, İlker (null; 2018-10-05)
Radiation heat transfer must be modeled when designing any high temperature solid particle solar receiver or particle-fluid heat exchanger, but computationally efficient radiation models are not currently available in coupled Computational Fluid Dynamics - Discrete Element Method (CFD-DEM) codes, which is the focus of this work. Monte Carlo ray tracing simulations were run to find view factors between particles in packed beds, and correlations were found to estimate both particle-particle and particle-wall ...
Citation Formats
E. E. Atak, “Investigation of Nanostructured Surfaces for Thermophotovoltaic Applications,” M.S. - Master of Science, Middle East Technical University, 2021.