Solar Thermal Aerogel Receiver (STAR)

Technology #18479

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Inventors
Professor Gang Chen
Department of Mechanical Engineering, MIT
External Link (web.mit.edu)
Professor Evelyn Wang
Department of Mechanical Engineering, MIT
External Link (drl.mit.edu)
Lee Weinstein
Department of Mechanical Engineering, MIT
Svetlana Boriskina
Department of Mechanical Engineering, MIT
External Link (www.mit.edu)
Sungwoo Yang
Department of Mechanical Engineering, MIT
External Link (yangsungwoo.wordpress.com)
Matthew Bierman
Department of Mechanical Engineering, MIT
Xiaopeng Huang
Department of Mechanical Engineering, MIT
James Loomis
Department of Mechanical Engineering, MIT
Lin Zhao
Department of Mechanical Engineering, MIT
Elise Strobach
Department of Mechanical Engineering, MIT
Thomas Cooper
Department of Mechanical Engineering, MIT
Bikramjit Bhatia
Department of Mechanical Engineering, MIT
Managed By
Christopher Noble
MIT Technology Licensing Officer - Clean and Renewable Energy
Patent Protection

SOLAR THERMAL AEROGEL RECEIVER (STAR)

Provisional Patent Application Filed
Publications
Modeling silica aerogel optical performance by determining its radiative properties
AIP Advances, 6, 025123 (2016)
Diverging polygon-based modeling (DPBM) of concentrated solar flux distributions
ScienceDirect, Volume 122, December 2015, Pages 24–35
Concentrating Solar Power
Chemical Reviews, 2015, 115 (23), pp 12797–12838

Applications

This receiver converts solar to thermal energy that can be used for heating and cooling applications (e.g. water), generating electricity, or energy storage.

Problem Addressed

Previous solar thermal receivers required a vacuum and are optimized with parabolic trough concentrators (PTCs). The STAR eliminates the use of a vacuum, reduces thermal losses, and is well suited for linear Fresnel reflector (LFR) concentrating optics, which are significantly cheaper than PTCs.

Technology

Current solar thermal receivers are insulated with vacuum tubes. This technology replaces these vacuum tubes with silica aerogels. Silica aerogels have an intrinsic spectral selectivity that allows them to pass solar radiation yet trap infrared radiation. In this way, they are both optically transparent and thermally insulating. By controlling the pH and drying time during processing, the aerogel microstructure can be optimized for this application. Through this technique, 95.5% solar weighted transmittance and a heat transfer coefficient <7W/m2K were demonstrated for an 8mm thick aerogel between 400oC and 100oC.  These properties were also retained after the sample was exposed to 400oC and >80% relative humidity for >100hours. By reducing the thermal losses from the system, aerogels also reduce the amount of optical concentration required for a desired thermal efficiency, which is why LFRs can be used instead of PTCs. STAR is not be susceptible to loss of vacuum which decreases annual energy average exergetic efficiency. Also, the STAR design allows for operating temperatures comparable to PTC receivers with less concentration area, meaning less land usage without sacrificing significant efficiency.

Advantages

  • More affordable receiver design than state-of-the-art
  • Reduced land usage with minimal exergetic efficiency sacrifice