High-Temperature Molten Meta-Material (MMM) for 50% Thermophotovoltaic
Abstract
A team with complementary expertise is formed to develop a high temperature plasmonic selective emitter based on a new concept of molten meta-material (MMM). MMM emitters will be the first metamaterial that is thermodynamically stable at high temperatures (800-1500 oC) oxidative environment. As a demonstration of the superb properties of the MMM, we will integrate the MMM emitter into a thermophotovoltaic (TPV) system with a matching PV cell for direct thermal-to-electrical energy conversion with unprecedentedly high efficiency of > 50%. Recent breakthroughs in TPV cells have achieved ~30% efficiency with blackbody emitters of 1200-2000 oC and ~ 40% efficiency with ultra-high temperature blackbody emitter over 2100 oC. Selective narrowband emitters have long been pursued to boost the TPV efficiency > 50% by only emitting photons around the bandgap of the TPV cell. However, none of them are stable due to degradation of constituent materials (metallic and dielectric) and their interfaces. Our team has recently developed a narrowband TPV emitter based on a novel molten meta-material (MMM). The emitters are uniquely suitable for high-T, high-efficiency (>50%) TPV. Our MMM emitters have already shown unprecedented stability (at 1200 oC in air for >100 hours) and are expected to be stable at 1500 oC in medium vacuum (10 mTorr) over 30 year after structural optimization in this project. The MMM can be used to produce narrowband emission with near-unity maximum emittance around the bandgap of a TPV cell. The emitter will be integrated with an efficient thin film TPV cell for high system-level performance with >50% thermal-to-electrical efficiency, >3.6 W/cm2 electrical power density, and >30 yrlifetime. This efficiency will be the highest for any single-stage thermal-to-electrical converters. It will lead to low cost, lightweight, noise-free, portable, high density power generation systems. The high-T efficient TPV will be a disruptive technology for power generation for a wide range of thermal energy sources, including heat from combustion of various fuels (gas, oil, wood, garbage, etc), high-temperature waste heat (e.g., from ships), solar heat, nuclear, etc.. The technology is especially suitable for portable power systems (e.g., for individuals in remote locations). As the only high-temperature air-stable metamaterial we are aware of, the MMM emitter can also be broadly applicable to applications beyond TPV, e.g., THz sources for portable detectors and miniaturized FTIR spectrometers, radiative cooling and thermal camouflage of high-temperature objects, etc.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 12, 2023
- Source ID
- N000142312392
Entities
People
- Zhaowei Liu
Organizations
- Office of Naval Research
- United States Navy
- University of California, San Diego