Thermophotovoltaic conversion efficiency measurement at high view factors

TL;DR

This paper introduces a new experimental setup for accurately measuring thermophotovoltaic efficiency at high view factors, revealing higher efficiencies and power densities than previous methods.

Contribution

It presents a standardized measurement method for TPV efficiency at high view factors, accounting for optical cavity effects and series resistance.

Findings

Achieved 26.4% TPV efficiency at high view factors

Measured power density of 4.3 W/cm2

Demonstrated improved accuracy over previous small view factor measurements

Abstract

A standardized method for measuring thermophotovoltaic (TPV) efficiency has not been yet established, which makes the reported results difficult to compare. Besides, most of the TPV efficiencies reported to date have been obtained using small view factors, i.e., large cell-to-emitter distances, so the impact of the series resistance is usually underestimated, and the optical cavity effects, i.e., the multiple reflections taking place between the emitter and the cell, are not accounted for experimentally. In this work, we present an experimental setup able to measure the TPV efficiency under high view factors (up to 0.98), by using small emitter-to-cell distances (< 1 mm). This allows a more accurate direct measurement of the TPV efficiency at higher power densities than previous works. As a result, a TPV efficiency of 26.4+-0.1 % and a power density of 4.3+-0.8 W/cm2 have been obtained for an InGaAs TPV cell with a back surface reflector irradiated by a graphite thermal emitter at 1592 C.