Effective Flux Temperature Formulation for Energy Conversion Using Microscale Thermal Radiation

Abstract

The non-Planckian spectrum of microscale thermal radiation is interpreted using a formulation for non-thermal radiation. The non-thermal aspects of the energy spectrum that results when radiating bodies are in close proximity are examined using the fluctuational electrodynamic approach to microscale thermal radiation. A definition of the effective flux temperature for microscale thermal radiation is presented. A technique to determine the entropy flux in a microscale field is obtained and used to calculate the effective flux temperature for chromium surfaces. The effective flux temperature of microscale radiation permits an assessment of the limits of the performance of proposed devices for the exploitation the spacing effect for energy conversion. The performance of a microscale thermophotovoltaic device is examined in terms of this flux temperature.