Three-layer solid infrared emitter with spectral output matched to low

Abstract

A three-layer solid infrared emitter having a spectral output matched to low bandgap TPV cells is provided. The three layers include inner and outer layers, and a core layer between the inner and outer layers. The core layer is of solid fiber reinforced undoped refractory oxide material. The inner layer of siC material absorbs radiation from the radiator, the core layer conducts heat from the inner layer to the outer layer. The core layer is a strengthening layer forming a diffuse reflector for stopping a shine-through of long wavelength radiation from the inner layer thereby preserving spectral selectivity in the outer layer. The emitter material may be cobalt doped, nickel doped, or combination of Ni or Co doped refractory oxides with erbia or a thin erbia selective emitter layer. The TPV generator has two concentric tubes with the emitter forming an outer tube and a radiator or mantle forming an inner tube surrounding a combustion chamber for radiating combustion heat from the chamber to the emitter for infrared emission. One/both concentric tubes may be of SiC acting as a near black body emitter/radiator. A resultant heat input to the inner tube during an upstream flow and a heat input to the inner and outer tubes during a downstream flow are adjustable such that the sun energy to the outer tube is constant along lengths of the outer tube thus maintaining the outer IR emitter tube at a constant temperature. Flow of combustion heat between the radiator or mantle and the emitter may be radial or axial.