Efficiency of Selective Solar Absorber in High Vacuum Flat Solar Thermal Panels: The Role of Emissivity

Davide De Maio; Carmine D'Alessandro; Antonio Caldarelli; Marilena Musto; Daniela De Luca; Emiliano Di Gennaro; Roberto Russo

doi:10.20944/preprints202008.0162.v2

Submit preprint
How it Works
Instructions for Authors
Subject Areas
Advisory Board
screening preprints
About
Awards
Log in/Register

Instructions for Authors
Awards
About
FAQ
Submit Log in/Register

Share this article with

Create alert

Email:

Load new image

preprints.org > engineering > energy and fuel technology > doi: 10.20944/preprints202008.0162.v2

Preprint Article Version 2 Preserved in Portico This version is not peer-reviewed

Efficiency of Selective Solar Absorber in High Vacuum Flat Solar Thermal Panels: The Role of Emissivity

^* ,

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)

A peer-reviewed article of this Preprint also exists.

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

This study refers to the optimization of a Selective Solar Absorber to improve the Sun-to-thermal conversion efficiency at mid temperatures in high vacuum flat thermal collectors. Efficiency has been evaluated by using analytical formula and a numerical thermal model. Both results have been experimentally validated using a commercial absorber in a custom experimental set-up. The optimization procedure aimed at obtaining Selective Solar Absorber is presented and discussed in the case of a metal dielectric multilayer based on Cr2O3 and Ti. The importance of adopting a real spectral emissivity curve to estimate high thermal efficiency at high temperatures in selective solar absorber is outlined. Optimized absorber multilayers can be 8% more efficient than the commercial alternative at 250 °C operating temperatures and up to 27% more efficient at 300 °C. Once the multilayer has been optimized the choice of a very low emissivity substrate such as copper allows to further improve efficiency and to reach stagnation temperature higher than 400 °C without Sun concentration.

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.

Download PDF

Comments (1)

Comment 1

Received: 20 October 2020
Commenter: Davide De Maio
Commenter's Conflict of Interests: Author

Comment: We strengthened our material and methods section, moved at the end of the paper. We added important details about the production process of the samples and materials characterization that were missing. We also added a comparison between simulations and the experimental results to better withstand our hypothesis and findings.

+ Respond to this comment

Not displayed online.

Importance: How significant is the paper to the field?

Outstanding/highlight paper

Significant contribution

Incremental contribution

No contribution

I am not qualified to judge

Soundness of evidence/arguments presented:

Conclusions well supported

Most conclusions supported (minor revision needed)

Incomplete evidence (major revision needed)

Hypothesis, unsupported conclusions, or proof-of-principle

I am not qualified to judge

Please leave your comment to this article below.

Mathematical equations can be typed in either LaTeX formats \\[ ... \\] or $$ ... $$, or MathML format <math> ... </math>. Try the LaTeX or MathML example.

Type equation:

Preview:

Copy equation into message below

Close menu

Please click a symbol to insert it into the message box below:

Please enter the link here:

Please enter a valid URL

Optionally, you can enter text that should appear as linked text:

Copy link into message below

Close menu

Please enter or paste the URL to the image here (please only use links to jpg/jpeg, png and gif images):

Please enter a valid URL

Copy image into message below

Close menu

Type author name or keywords to filter the list of references in this group (you can add a new citation under Bibliography):

No existing citations in Discussion Group

Wikify editor is a simple editor for wiki-style mark-up. It was written by MDPI for Sciforum in 2014. The rendering of the mark-up is based on Wiky.php with some tweaks. Rendering of mathematical equations is done with MathJax. Please send us a message for support or for reporting bugs.

Close menu

Please declare any conflicts of interest you may have with this paper, financial or otherwise.

I do not have a conflict of interest

I would like to declare a conflict of interest

Display my name on the website Send my name and email address to the authors

Captcha

Renew

I accept the following conditions:

Comments must follow the standards of professional discourse and should focus on the scientific content of the article. Insulting or offensive language, personal attacks and off-topic remarks will not be permitted. Comments must be written in English. Preprints reserves the right to remove comments without notice. Readers who post comments are obliged to declare any competing interests, financial or otherwise.

We encourage comments and feedback from a broad range of readers. See criteria for comments and our Diversity statement.

Leave a public comment
Send a private comment to the author(s)

* All users must log in before leaving a comment

what’s this?

Add a record of this review to Publons to track and showcase your reviewing expertise across the world’s journals.

Downloads 0

Comments 1

Metrics 0

Get PDF Cite Share 0

Bookmark BibSonomy Mendeley Reddit Delicious

Alerts

Notify me about updates to this article or when a peer-reviewed version is published.

Preprints.org is a free preprint server subsidized by MDPI in Basel, Switzerland.

MDPI Initiatives

SciProfiles
Sciforum
Encyclopedia
MDPI Books
Scilit
Proceedings
JAMS

Important links

How it Works
Advisory Board
FAQ
Friendly Journals
Instructions for Authors
About
Statistics

Choose the area that interest you and we will send you notifications of new preprints at your preferred frequency.

Disclaimer

We use cookies on our website to ensure you get the best experience.
Read more about our cookies here.

RSS feed for

Preprints: The Multidisciplinary Preprint Platform

Paste the URL in your RSS reader:

https://www.preprints.org/rss

If you want to subscribe our website in subject-wide, you could find the URL by choosing in the following:

https://www.preprints.org/rss

Please note that by using ScienceDirect RSS feeds, you agree to our Terms of Use and Privacy Policy.