Concepedia

Concentrated solar thermoelectric generators

Lauryn L. Baranowski, G. Jeffrey Snyder, Eric S. Toberer

Energy & Environmental Science · 2012 · 280 citations · 37 references

TL;DR

Solar thermoelectric generators convert concentrated sunlight into electricity, and future progress hinges on materials enabling higher operating temperatures or greater efficiency. The paper develops a detailed balance model for STEGs and applies it to both state‑of‑the‑art and idealized materials. The model employs thermoelectric compatibility theory to yield analytic efficiency solutions for idealized materials with temperature‑dependent properties. The model predicts maximum theoretical efficiencies and design rules, showing that with current materials a 100 kW m⁻² flux and 1000 °C hot side yields 15.9% efficiency, while a zT = 2 material at 1500 °C could reach 30.6%.

Abstract

Solar thermoelectric generators (STEGs) are solid state heat engines that generate electricity from concentrated sunlight. In this paper, we develop a novel detailed balance model for STEGs and apply this model to both state-of-the-art and idealized materials. This model uses thermoelectric compatibility theory to provide analytic solutions to device efficiency in idealized materials with temperature-dependent properties. The results of this modeling allow us to predict maximum theoretical STEG efficiencies and suggest general design rules for STEGs. With today's materials, a STEG with an incident flux of 100 kW m−2 and a hot side temperature of 1000 °C could achieve 15.9% generator efficiency, making STEGs competitive with concentrated solar power plants. Future developments will depend on materials that can provide higher operating temperatures or higher material efficiency. For example, a STEG with zT = 2 at 1500 °C would have an efficiency of 30.6%.