Seminar-Dr. Andrej Lenert, University of Michigan

  • 2018-08-02
  • Seminar-Dr. Andrej Lenert, University of Michigan
Andrej Lenert is an Assistant Professor in the Department of Chemical Engineering at the University of Michigan. His interests lie at the intersection of heat and mass transfer, optics, and nanomaterials. He is focused on addressing global challenges at the energy-water nexus by bridging the gap between system level design and mesoscale materials science. He completed his PhD in Mechanical Engineering at MIT in 2014, under the supervision of Evelyn Wang. He was then a postdoctoral fellow at the University of Michigan, working with the Nanoscale Transport Lab (Pramod Reddy and Edgar Meyhofer) and the Center for Photonic and Multiscale Nanomaterials. Andrej is a former fellow of the MIT Energy Initiative and the Martin Family Society of Fellows for Sustainability. In 2016, he was named to the Forbes 30 under 30 list in Science.

By manipulating the structure of materials at the nanoscale, we can tune the spectrum of thermal radiation. In doing so, we can selectively enhance or suppress certain modes linked to either desirable or undesirable properties. Such energy-selective transport holds promise for more efficient solar power generation and thermal management of buildings. In this talk, I will discuss two energy-selective transport mechanisms and their applications. The first utilizes nanoporous materials, such as aerogels, where energy-selectivity is based on how far radiation travels within a material. By targeting short photon free paths at long wavelengths, I show how these materials can improve the efficiency of concentrated solar power and passive radiative cooling. The second utilizes high-temperature nanophotonic materials, where energy-selectivity is based on the interaction of thermal radiation with wavelength-scale structures. By suppressing radiative exchange at low energies, I demonstrate a solar thermal photovoltaic (STPV) device that is an order of magnitude more efficient than previous STPVs and has the potential to exceed the limit of single-junction solar cells. With integration of thermal storage, these technologies can become an important part of distributed energy systems and may lead to increased adoption of intermittent renewables.