Version 1
: Received: 5 August 2020 / Approved: 6 August 2020 / Online: 6 August 2020 (11:28:27 CEST)
Version 2
: Received: 19 October 2020 / Approved: 20 October 2020 / Online: 20 October 2020 (12:18:01 CEST)
De Maio, D.; D’Alessandro, C.; Caldarelli, A.; De Luca, D.; Di Gennaro, E.; Russo, R.; Musto, M. A Selective Solar Absorber for Unconcentrated Solar Thermal Panels. Energies 2021, 14, 900. https://doi.org/10.3390/en14040900
De Maio, D.; D’Alessandro, C.; Caldarelli, A.; De Luca, D.; Di Gennaro, E.; Russo, R.; Musto, M. A Selective Solar Absorber for Unconcentrated Solar Thermal Panels. Energies 2021, 14, 900. https://doi.org/10.3390/en14040900
De Maio, D.; D’Alessandro, C.; Caldarelli, A.; De Luca, D.; Di Gennaro, E.; Russo, R.; Musto, M. A Selective Solar Absorber for Unconcentrated Solar Thermal Panels. Energies 2021, 14, 900. https://doi.org/10.3390/en14040900
De Maio, D.; D’Alessandro, C.; Caldarelli, A.; De Luca, D.; Di Gennaro, E.; Russo, R.; Musto, M. A Selective Solar Absorber for Unconcentrated Solar Thermal Panels. Energies 2021, 14, 900. https://doi.org/10.3390/en14040900
Abstract
A multilayer structure on a metallic substrate has been optically simulated and the optimization procedure aimed at obtaining Selective Solar Absorber (SSA) is discussed. This study refers to flat high vacuum thermal collectors and the overall Sun-to-thermal conversion efficiency has been evaluated using analytical formula and numerical thermal model. Both methods are in agreement and they have been validated using experimental results on a commercial absorber. The importance of a low emittance value to obtain high thermal efficiency at high temperatures and high stagnation temperature in selective solar absorber is highlighted. Optimized absorbers can be 8% more efficient than the commercial alternative at 250 °C operating temperatures and up to 27% more efficient at 300 °C. A stagnation temperature higher than 400 °C can be reached without Sun concentration if the proper design is adopted.
Keywords
thermal emittance; conversion efficiency; selective solar absorber; thermal energy; evacuated flat panel; solar energy
Subject
Engineering, Energy and Fuel Technology
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.