Design Of Metamaterial For High Thermophotovoltaic Emitter

Abstract

In this work thermophotovoltaic emitter designed of metamaterial were presented. The broad band and wide angle emissivity above cut-off wavelength were obtained. The metamaterial nano-cone was designed from tungsten and aluminum oxide by using COMSOL Multiphysics software. To get broadband emission, the geometric parameter optimization of the bottom radius, thickness of dielectric, and the width of the unit cell were conducted, while parameters such as nano-cone height, top radius of nano-cone and ground tungsten thickness were fixed in this study. The numerical simulation results showed that the proposed emitter had an average emissivity of 0.975 within the targeted wavelength, which ranged from 0.5 µm to 1.8 µm. The obtained high emissivity is because of excitation of different physical mechanism of absorption. Unlike black body the designed nano-cone metamaterial emitter emit only selective wavelength of radiation. Moreover, the designed nano-cone metamaterial emitter obtained 3.79%, 8.4%, 15.49%, 24.9%, 36.6%, 50.3%, 64.6%, 80% spectral efficiency of with GaSb band gap of 0.74 ev or 1.8 µm wavelength at 900 K, 1000 K, 1100 K, 1200 K, 1300 K, 1400 K, 1500 K and 1600 K respectively. In general as temperature increases the spectral efficiency also increases, this shows the emitter working at high temperature play a vital role in enhancing TPV efficiency. Particularly, selective emitter maximize efficiency by suppressing the out band radiations. Over all, in this paper selective metamaterial emitter were designed and this designed metamaterial emitter has high average emittance over required wavelength