title: Design and global optimization of high-efficiency solar thermal systems with tungsten cermets.
abstract: Solar thermal, thermoelectric, and thermophotovoltaic (TPV) systems have high maximum theoretical efficiencies; experimental systems fall short because of losses by selective solar absorbers and TPV selective emitters. To improve these critical components, we study a class of materials known as cermets. While our approach is completely general, the most promising cermet candidate combines nanoparticles of silica and tungsten. We find that 4-layer silica-tungsten cermet selective solar absorbers can achieve thermal transfer efficiencies of 84.3% at 400 K, and 75.59% at 1000 K, exceeding comparable literature values. Three layer silica-tungsten cermets can also be used as selective emitters for InGaAsSb-based thermophotovoltaic systems, with projected overall system energy conversion efficiencies of 10.66% at 1000 K using realistic design parameters. The marginal benefit of adding more than 4 cermet layers is small (less than 0.26%, relative).
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139, USA.
authors.forename: David
authors.initials: D
authors.lastname: Chester
authors.forename: Peter
authors.initials: P
authors.lastname: Bermel
authors.forename: John D
authors.initials: JD
authors.lastname: Joannopoulos
authors.forename: Marin
authors.initials: M
authors.lastname: Soljacic
authors.forename: Ivan
authors.initials: I
authors.lastname: Celanovic