University of Michigan

Massachusetts Institute of Technology

Andrej Lenert

Stephen R Forrest

Gang Paul Chen

Evelyn N Wang

David M Bierman

Kenneth McEnaney

Hannah Meekyung Kim

Tobias Eugene Burger

Marin Soljacic

Lee A Weinstein

Kyusang Lee

Hadi Ghasemi

Sungwoo Yang

Svetlana Boriskina

Ivan Celanovic

Dejiu Fan

Daniel Kraemer

Nenad Miljkovic

Walker Chan

Byungjun Lee

Young Suk Nam

Selcuk Yerci

Deiju Fan

To reach high efficiencies, thermophotovoltaic cells must utilize the broad spectrum of a radiative thermal source. One promising approach to overcome this challenge is to have low-energy photons reflected and reabsorbed by the thermal emitter, where their energy can have another chance at contributing toward photogeneration in the cell. However, current methods for photon recuperation are limited by insufficient bandwidth or parasitic absorption, resulting in large efficiency losses relative to theoretical limits. This work demonstrates nearly perfect reflection of low-energy photons (˜99%) by embedding an air layer within the TPV cell. This result represents a four-fold reduction in parasitic absorption relative to existing TPV cells. As out-of-band reflectance approaches unity, TPV efficiency becomes nearly insensitive to cell bandgap and emitter temperature. Accessing this regime unlocks a range of possible materials and heat sources that were previously inaccessible to TPV energy conversion.

Thermophotovoltaic cells with integrated air-bridge for improved efficiency

A thermal management system for a body to be exposed to solar radiation includes an infrared radiating element and a solar-scattering cover disposed on or integrated with the infrared radiating element. The thermal management system further includes a thermal storage sub-system in fluid connection with a solar panel via thermal interconnections.

Thermal management system

Thermophotovoltaic (TPV) systems and devices with improved efficiencies are disclosed herein. In one example, a thermophotovoltaic (TPV) cell includes an active layer; a back-surface reflective (BSR) layer; and a spacer layer positioned between the active layer and back-surface reflective layer.

Thin-film thermophotovoltaic cells

A thermal management system for a body to be exposed to solar radiation includes an infrared radiating element and a solar-scattering cover disposed on or integrated with the infrared radiating element.

A single-stack, solar power receiver comprising both a thermal absorber layer and a photovoltaic cell layer. The stack includes an aerogel layer, that is optically transparent and thermally insulating ('OTTI'); a spectrally selective high thermal conductivity ('SSTC') thermal absorber layer; a bottom OTTI layer; and a PV cell layer. The SSTC layer includes a set of fins that substantially blocks solar radiation absorption in the band where PV cells are most sensitive. Photons with energies above or below this band block range are absorbed by the fins and the absorbed heat is conducted to pipes in the fin structure carrying a heated thermal working fluid to heat storage. Photons with energy in the band block range are reflected by the SSTC fins to the PV cell layer. The bottom OTTI aerogel layer keeps the PV cell operating near ambient temperature. The PV cell converts incident solar radiation to electrical energy.

Internally-heated thermal and externally-cool photovoltaic cascade solar energy system for full solar spectrum utilization

A solar thermal photovoltaic device, and method of forming same, includes a solar absorber and a spectrally selective emitter formed on either side of a thermally conductive substrate. The solar absorber is configured to absorb incident solar radiation. The solar absorber and the spectrally selective emitter are configured with an optimized emitter-to-absorber area ratio. The solar thermal photovoltaic device also includes a photovoltaic cell in thermal communication with the spectrally selective emitter. The spectrally selective emitter is configured to permit high emittance for energies above a bandgap of the photovoltaic cell and configured to permit low emittance for energies below the bandgap.

Spectrally-engineered solar thermal photovoltaic devices

Growing community of inventors

Ann Arbor, MI, United States of America

Andrej Lenert